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        let mut removed_buffer_ids = Vec::new();
2049
2050        while let Some(excerpt_id) = excerpt_ids.next() {
2051            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2052            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2053            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2054
2055            if let Some(mut excerpt) = cursor.item() {
2056                if excerpt.id != excerpt_id {
2057                    continue;
2058                }
2059                let mut old_start = cursor.start().1;
2060
2061                // Skip over the removed excerpt.
2062                'remove_excerpts: loop {
2063                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2064                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2065                        if buffer_state.excerpts.is_empty() {
2066                            log::debug!(
2067                                "removing buffer and diff for buffer {}",
2068                                excerpt.buffer_id
2069                            );
2070                            buffers.remove(&excerpt.buffer_id);
2071                            removed_buffer_ids.push(excerpt.buffer_id);
2072                        }
2073                    }
2074                    cursor.next(&());
2075
2076                    // Skip over any subsequent excerpts that are also removed.
2077                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2078                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2079                        if let Some(next_excerpt) = cursor.item() {
2080                            if next_excerpt.locator == *next_locator {
2081                                excerpt_ids.next();
2082                                excerpt = next_excerpt;
2083                                continue 'remove_excerpts;
2084                            }
2085                        }
2086                    }
2087
2088                    break;
2089                }
2090
2091                // When removing the last excerpt, remove the trailing newline from
2092                // the previous excerpt.
2093                if cursor.item().is_none() && old_start.value > 0 {
2094                    old_start.value -= 1;
2095                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2096                }
2097
2098                // Push an edit for the removal of this run of excerpts.
2099                let old_end = cursor.start().1;
2100                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2101                edits.push(Edit {
2102                    old: old_start..old_end,
2103                    new: new_start..new_start,
2104                });
2105            }
2106        }
2107        let suffix = cursor.suffix(&());
2108        let changed_trailing_excerpt = suffix.is_empty();
2109        new_excerpts.append(suffix, &());
2110        drop(cursor);
2111        snapshot.excerpts = new_excerpts;
2112        for buffer_id in removed_buffer_ids {
2113            self.diffs.remove(&buffer_id);
2114            snapshot.diffs.remove(&buffer_id);
2115        }
2116
2117        if changed_trailing_excerpt {
2118            snapshot.trailing_excerpt_update_count += 1;
2119        }
2120
2121        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2122        cx.emit(Event::Edited {
2123            singleton_buffer_edited: false,
2124            edited_buffer: None,
2125        });
2126        cx.emit(Event::ExcerptsRemoved { ids });
2127        cx.notify();
2128    }
2129
2130    pub fn wait_for_anchors<'a>(
2131        &self,
2132        anchors: impl 'a + Iterator<Item = Anchor>,
2133        cx: &mut Context<Self>,
2134    ) -> impl 'static + Future<Output = Result<()>> {
2135        let borrow = self.buffers.borrow();
2136        let mut error = None;
2137        let mut futures = Vec::new();
2138        for anchor in anchors {
2139            if let Some(buffer_id) = anchor.buffer_id {
2140                if let Some(buffer) = borrow.get(&buffer_id) {
2141                    buffer.buffer.update(cx, |buffer, _| {
2142                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2143                    });
2144                } else {
2145                    error = Some(anyhow!(
2146                        "buffer {buffer_id} is not part of this multi-buffer"
2147                    ));
2148                    break;
2149                }
2150            }
2151        }
2152        async move {
2153            if let Some(error) = error {
2154                Err(error)?;
2155            }
2156            for future in futures {
2157                future.await?;
2158            }
2159            Ok(())
2160        }
2161    }
2162
2163    pub fn text_anchor_for_position<T: ToOffset>(
2164        &self,
2165        position: T,
2166        cx: &App,
2167    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2168        let snapshot = self.read(cx);
2169        let anchor = snapshot.anchor_before(position);
2170        let buffer = self
2171            .buffers
2172            .borrow()
2173            .get(&anchor.buffer_id?)?
2174            .buffer
2175            .clone();
2176        Some((buffer, anchor.text_anchor))
2177    }
2178
2179    fn on_buffer_event(
2180        &mut self,
2181        buffer: Entity<Buffer>,
2182        event: &language::BufferEvent,
2183        cx: &mut Context<Self>,
2184    ) {
2185        cx.emit(match event {
2186            language::BufferEvent::Edited => Event::Edited {
2187                singleton_buffer_edited: true,
2188                edited_buffer: Some(buffer.clone()),
2189            },
2190            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2191            language::BufferEvent::Saved => Event::Saved,
2192            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2193            language::BufferEvent::Reloaded => Event::Reloaded,
2194            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2195            language::BufferEvent::LanguageChanged => {
2196                Event::LanguageChanged(buffer.read(cx).remote_id())
2197            }
2198            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2199            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2200            language::BufferEvent::Closed => Event::Closed,
2201            language::BufferEvent::Discarded => Event::Discarded,
2202            language::BufferEvent::CapabilityChanged => {
2203                self.capability = buffer.read(cx).capability();
2204                Event::CapabilityChanged
2205            }
2206            language::BufferEvent::Operation { .. } => return,
2207        });
2208    }
2209
2210    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2211        self.sync(cx);
2212        let mut snapshot = self.snapshot.borrow_mut();
2213        let diff = diff.read(cx);
2214        let buffer_id = diff.buffer_id;
2215        let diff = diff.snapshot(cx);
2216        snapshot.diffs.insert(buffer_id, diff);
2217    }
2218
2219    fn buffer_diff_changed(
2220        &mut self,
2221        diff: Entity<BufferDiff>,
2222        range: Range<text::Anchor>,
2223        cx: &mut Context<Self>,
2224    ) {
2225        self.sync(cx);
2226
2227        let diff = diff.read(cx);
2228        let buffer_id = diff.buffer_id;
2229        let buffers = self.buffers.borrow();
2230        let Some(buffer_state) = buffers.get(&buffer_id) else {
2231            return;
2232        };
2233
2234        let buffer = buffer_state.buffer.read(cx);
2235        let diff_change_range = range.to_offset(buffer);
2236
2237        let new_diff = diff.snapshot(cx);
2238        let mut snapshot = self.snapshot.borrow_mut();
2239        let base_text_changed = snapshot
2240            .diffs
2241            .get(&buffer_id)
2242            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2243
2244        snapshot.diffs.insert(buffer_id, new_diff);
2245
2246        let mut excerpt_edits = Vec::new();
2247        for locator in &buffer_state.excerpts {
2248            let mut cursor = snapshot
2249                .excerpts
2250                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2251            cursor.seek_forward(&Some(locator), Bias::Left, &());
2252            if let Some(excerpt) = cursor.item() {
2253                if excerpt.locator == *locator {
2254                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2255                    if diff_change_range.end < excerpt_buffer_range.start
2256                        || diff_change_range.start > excerpt_buffer_range.end
2257                    {
2258                        continue;
2259                    }
2260                    let excerpt_start = cursor.start().1;
2261                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2262                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2263                        diff_change_range
2264                            .start
2265                            .saturating_sub(excerpt_buffer_range.start),
2266                    );
2267                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2268                        diff_change_range
2269                            .end
2270                            .saturating_sub(excerpt_buffer_range.start),
2271                    );
2272                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2273                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2274                    excerpt_edits.push(Edit {
2275                        old: edit_start..edit_end,
2276                        new: edit_start..edit_end,
2277                    });
2278                }
2279            }
2280        }
2281
2282        self.sync_diff_transforms(
2283            &mut snapshot,
2284            excerpt_edits,
2285            DiffChangeKind::DiffUpdated {
2286                base_changed: base_text_changed,
2287            },
2288        );
2289        cx.emit(Event::Edited {
2290            singleton_buffer_edited: false,
2291            edited_buffer: None,
2292        });
2293    }
2294
2295    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2296        self.buffers
2297            .borrow()
2298            .values()
2299            .map(|state| state.buffer.clone())
2300            .collect()
2301    }
2302
2303    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2304        self.buffers
2305            .borrow()
2306            .get(&buffer_id)
2307            .map(|state| state.buffer.clone())
2308    }
2309
2310    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2311        self.point_to_buffer_offset(point, cx)
2312            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2313    }
2314
2315    pub fn settings_at<'a, T: ToOffset>(&self, point: T, cx: &'a App) -> Cow<'a, LanguageSettings> {
2316        let mut language = None;
2317        let mut file = None;
2318        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2319            let buffer = buffer.read(cx);
2320            language = buffer.language_at(offset);
2321            file = buffer.file();
2322        }
2323        language_settings(language.map(|l| l.name()), file, cx)
2324    }
2325
2326    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2327        self.buffers
2328            .borrow()
2329            .values()
2330            .for_each(|state| f(&state.buffer))
2331    }
2332
2333    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2334        if let Some(title) = self.title.as_ref() {
2335            return title.into();
2336        }
2337
2338        if let Some(buffer) = self.as_singleton() {
2339            if let Some(file) = buffer.read(cx).file() {
2340                return file.file_name(cx).to_string_lossy();
2341            }
2342        }
2343
2344        "untitled".into()
2345    }
2346
2347    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2348        self.title = Some(title);
2349        cx.notify();
2350    }
2351
2352    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2353    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2354        for buffer_state in self.buffers.borrow().values() {
2355            buffer_state
2356                .buffer
2357                .update(cx, |buffer, _cx| buffer.refresh_preview());
2358        }
2359    }
2360
2361    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2362    pub fn preserve_preview(&self, cx: &App) -> bool {
2363        self.buffers
2364            .borrow()
2365            .values()
2366            .all(|state| state.buffer.read(cx).preserve_preview())
2367    }
2368
2369    #[cfg(any(test, feature = "test-support"))]
2370    pub fn is_parsing(&self, cx: &App) -> bool {
2371        self.as_singleton().unwrap().read(cx).is_parsing()
2372    }
2373
2374    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2375        let buffer_id = diff.read(cx).buffer_id;
2376        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2377        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2378    }
2379
2380    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2381        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2382    }
2383
2384    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2385        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2386    }
2387
2388    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2389        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2390    }
2391
2392    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2393        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2394        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2395    }
2396
2397    pub fn all_diff_hunks_expanded(&self) -> bool {
2398        self.snapshot.borrow().all_diff_hunks_expanded
2399    }
2400
2401    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2402        self.read(cx)
2403            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2404            .nth(1)
2405            .is_some()
2406    }
2407
2408    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2409        let snapshot = self.read(cx);
2410        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2411        let offset_range = range.to_offset(&snapshot);
2412        cursor.seek(&offset_range.start, Bias::Left, &());
2413        while let Some(item) = cursor.item() {
2414            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2415                break;
2416            }
2417            if item.hunk_info().is_some() {
2418                return true;
2419            }
2420            cursor.next(&());
2421        }
2422        false
2423    }
2424
2425    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2426        let snapshot = self.read(cx);
2427        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2428        for range in ranges {
2429            let range = range.to_point(&snapshot);
2430            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2431            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2432            let start = start.saturating_sub(1);
2433            let end = snapshot.len().min(end + 1);
2434            cursor.seek(&start, Bias::Right, &());
2435            while let Some(item) = cursor.item() {
2436                if *cursor.start() >= end {
2437                    break;
2438                }
2439                if item.hunk_info().is_some() {
2440                    return true;
2441                }
2442                cursor.next(&());
2443            }
2444        }
2445        false
2446    }
2447
2448    pub fn expand_or_collapse_diff_hunks_inner(
2449        &mut self,
2450        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2451        expand: bool,
2452        cx: &mut Context<Self>,
2453    ) {
2454        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2455            return;
2456        }
2457        self.sync(cx);
2458        let mut snapshot = self.snapshot.borrow_mut();
2459        let mut excerpt_edits = Vec::new();
2460        for (range, end_excerpt_id) in ranges {
2461            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2462                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2463                    continue;
2464                }
2465                let start = Anchor::in_buffer(
2466                    diff_hunk.excerpt_id,
2467                    diff_hunk.buffer_id,
2468                    diff_hunk.buffer_range.start,
2469                );
2470                let end = Anchor::in_buffer(
2471                    diff_hunk.excerpt_id,
2472                    diff_hunk.buffer_id,
2473                    diff_hunk.buffer_range.end,
2474                );
2475                let start = snapshot.excerpt_offset_for_anchor(&start);
2476                let end = snapshot.excerpt_offset_for_anchor(&end);
2477                excerpt_edits.push(text::Edit {
2478                    old: start..end,
2479                    new: start..end,
2480                });
2481            }
2482        }
2483
2484        self.sync_diff_transforms(
2485            &mut snapshot,
2486            excerpt_edits,
2487            DiffChangeKind::ExpandOrCollapseHunks { expand },
2488        );
2489        cx.emit(Event::DiffHunksToggled);
2490        cx.emit(Event::Edited {
2491            singleton_buffer_edited: false,
2492            edited_buffer: None,
2493        });
2494    }
2495
2496    pub fn expand_or_collapse_diff_hunks(
2497        &mut self,
2498        ranges: Vec<Range<Anchor>>,
2499        expand: bool,
2500        cx: &mut Context<Self>,
2501    ) {
2502        let snapshot = self.snapshot.borrow().clone();
2503        let ranges = ranges.iter().map(move |range| {
2504            let end_excerpt_id = range.end.excerpt_id;
2505            let range = range.to_point(&snapshot);
2506            let mut peek_end = range.end;
2507            if range.end.row < snapshot.max_row().0 {
2508                peek_end = Point::new(range.end.row + 1, 0);
2509            };
2510            (range.start..peek_end, end_excerpt_id)
2511        });
2512        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2513    }
2514
2515    pub fn resize_excerpt(
2516        &mut self,
2517        id: ExcerptId,
2518        range: Range<text::Anchor>,
2519        cx: &mut Context<Self>,
2520    ) {
2521        self.sync(cx);
2522
2523        let mut snapshot = self.snapshot.borrow_mut();
2524        let locator = snapshot.excerpt_locator_for_id(id);
2525        let mut new_excerpts = SumTree::default();
2526        let mut cursor = snapshot
2527            .excerpts
2528            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2529        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2530
2531        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2532        new_excerpts.append(prefix, &());
2533
2534        let mut excerpt = cursor.item().unwrap().clone();
2535        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2536
2537        excerpt.range.context.start = range.start;
2538        excerpt.range.context.end = range.end;
2539        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2540
2541        excerpt.text_summary = excerpt
2542            .buffer
2543            .text_summary_for_range(excerpt.range.context.clone());
2544
2545        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2546        let old_start_offset = cursor.start().1;
2547        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2548        let edit = Edit {
2549            old: old_start_offset..old_start_offset + old_text_len,
2550            new: new_start_offset..new_start_offset + new_text_len,
2551        };
2552
2553        if let Some(last_edit) = edits.last_mut() {
2554            if last_edit.old.end == edit.old.start {
2555                last_edit.old.end = edit.old.end;
2556                last_edit.new.end = edit.new.end;
2557            } else {
2558                edits.push(edit);
2559            }
2560        } else {
2561            edits.push(edit);
2562        }
2563
2564        new_excerpts.push(excerpt, &());
2565
2566        cursor.next(&());
2567
2568        new_excerpts.append(cursor.suffix(&()), &());
2569
2570        drop(cursor);
2571        snapshot.excerpts = new_excerpts;
2572
2573        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2574        cx.emit(Event::Edited {
2575            singleton_buffer_edited: false,
2576            edited_buffer: None,
2577        });
2578        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2579        cx.notify();
2580    }
2581
2582    pub fn expand_excerpts(
2583        &mut self,
2584        ids: impl IntoIterator<Item = ExcerptId>,
2585        line_count: u32,
2586        direction: ExpandExcerptDirection,
2587        cx: &mut Context<Self>,
2588    ) {
2589        if line_count == 0 {
2590            return;
2591        }
2592        self.sync(cx);
2593        let mut snapshot = self.snapshot.borrow_mut();
2594
2595        let ids = ids.into_iter().collect::<Vec<_>>();
2596        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2597        let mut new_excerpts = SumTree::default();
2598        let mut cursor = snapshot
2599            .excerpts
2600            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2601        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2602
2603        for locator in &locators {
2604            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2605            new_excerpts.append(prefix, &());
2606
2607            let mut excerpt = cursor.item().unwrap().clone();
2608            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2609
2610            let up_line_count = if direction.should_expand_up() {
2611                line_count
2612            } else {
2613                0
2614            };
2615
2616            let start_row = excerpt
2617                .range
2618                .context
2619                .start
2620                .to_point(&excerpt.buffer)
2621                .row
2622                .saturating_sub(up_line_count);
2623            let start_point = Point::new(start_row, 0);
2624            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2625
2626            let down_line_count = if direction.should_expand_down() {
2627                line_count
2628            } else {
2629                0
2630            };
2631
2632            let mut end_point = excerpt.buffer.clip_point(
2633                excerpt.range.context.end.to_point(&excerpt.buffer)
2634                    + Point::new(down_line_count, 0),
2635                Bias::Left,
2636            );
2637            end_point.column = excerpt.buffer.line_len(end_point.row);
2638            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2639            excerpt.max_buffer_row = end_point.row;
2640
2641            excerpt.text_summary = excerpt
2642                .buffer
2643                .text_summary_for_range(excerpt.range.context.clone());
2644
2645            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2646            let old_start_offset = cursor.start().1;
2647            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2648            let edit = Edit {
2649                old: old_start_offset..old_start_offset + old_text_len,
2650                new: new_start_offset..new_start_offset + new_text_len,
2651            };
2652
2653            if let Some(last_edit) = edits.last_mut() {
2654                if last_edit.old.end == edit.old.start {
2655                    last_edit.old.end = edit.old.end;
2656                    last_edit.new.end = edit.new.end;
2657                } else {
2658                    edits.push(edit);
2659                }
2660            } else {
2661                edits.push(edit);
2662            }
2663
2664            new_excerpts.push(excerpt, &());
2665
2666            cursor.next(&());
2667        }
2668
2669        new_excerpts.append(cursor.suffix(&()), &());
2670
2671        drop(cursor);
2672        snapshot.excerpts = new_excerpts;
2673
2674        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2675        cx.emit(Event::Edited {
2676            singleton_buffer_edited: false,
2677            edited_buffer: None,
2678        });
2679        cx.emit(Event::ExcerptsExpanded { ids });
2680        cx.notify();
2681    }
2682
2683    fn sync(&self, cx: &App) {
2684        let mut snapshot = self.snapshot.borrow_mut();
2685        let mut excerpts_to_edit = Vec::new();
2686        let mut non_text_state_updated = false;
2687        let mut is_dirty = false;
2688        let mut has_deleted_file = false;
2689        let mut has_conflict = false;
2690        let mut edited = false;
2691        let mut buffers = self.buffers.borrow_mut();
2692        for buffer_state in buffers.values_mut() {
2693            let buffer = buffer_state.buffer.read(cx);
2694            let version = buffer.version();
2695            let non_text_state_update_count = buffer.non_text_state_update_count();
2696
2697            let buffer_edited = version.changed_since(&buffer_state.last_version);
2698            let buffer_non_text_state_updated =
2699                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2700            if buffer_edited || buffer_non_text_state_updated {
2701                buffer_state.last_version = version;
2702                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2703                excerpts_to_edit.extend(
2704                    buffer_state
2705                        .excerpts
2706                        .iter()
2707                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2708                );
2709            }
2710
2711            edited |= buffer_edited;
2712            non_text_state_updated |= buffer_non_text_state_updated;
2713            is_dirty |= buffer.is_dirty();
2714            has_deleted_file |= buffer
2715                .file()
2716                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2717            has_conflict |= buffer.has_conflict();
2718        }
2719        if edited {
2720            snapshot.edit_count += 1;
2721        }
2722        if non_text_state_updated {
2723            snapshot.non_text_state_update_count += 1;
2724        }
2725        snapshot.is_dirty = is_dirty;
2726        snapshot.has_deleted_file = has_deleted_file;
2727        snapshot.has_conflict = has_conflict;
2728
2729        for (id, diff) in self.diffs.iter() {
2730            if snapshot.diffs.get(&id).is_none() {
2731                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2732            }
2733        }
2734
2735        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2736
2737        let mut edits = Vec::new();
2738        let mut new_excerpts = SumTree::default();
2739        let mut cursor = snapshot
2740            .excerpts
2741            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2742
2743        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2744            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2745            let old_excerpt = cursor.item().unwrap();
2746            let buffer = buffer.read(cx);
2747            let buffer_id = buffer.remote_id();
2748
2749            let mut new_excerpt;
2750            if buffer_edited {
2751                edits.extend(
2752                    buffer
2753                        .edits_since_in_range::<usize>(
2754                            old_excerpt.buffer.version(),
2755                            old_excerpt.range.context.clone(),
2756                        )
2757                        .map(|edit| {
2758                            let excerpt_old_start = cursor.start().1;
2759                            let excerpt_new_start =
2760                                ExcerptOffset::new(new_excerpts.summary().text.len);
2761                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2762                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2763                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2764                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2765                            Edit {
2766                                old: old_start..old_end,
2767                                new: new_start..new_end,
2768                            }
2769                        }),
2770                );
2771
2772                new_excerpt = Excerpt::new(
2773                    old_excerpt.id,
2774                    locator.clone(),
2775                    buffer_id,
2776                    buffer.snapshot(),
2777                    old_excerpt.range.clone(),
2778                    old_excerpt.has_trailing_newline,
2779                );
2780            } else {
2781                new_excerpt = old_excerpt.clone();
2782                new_excerpt.buffer = buffer.snapshot();
2783            }
2784
2785            new_excerpts.push(new_excerpt, &());
2786            cursor.next(&());
2787        }
2788        new_excerpts.append(cursor.suffix(&()), &());
2789
2790        drop(cursor);
2791        snapshot.excerpts = new_excerpts;
2792
2793        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2794    }
2795
2796    fn sync_diff_transforms(
2797        &self,
2798        snapshot: &mut MultiBufferSnapshot,
2799        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2800        change_kind: DiffChangeKind,
2801    ) {
2802        if excerpt_edits.is_empty() {
2803            return;
2804        }
2805
2806        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2807        let mut old_diff_transforms = snapshot
2808            .diff_transforms
2809            .cursor::<(ExcerptOffset, usize)>(&());
2810        let mut new_diff_transforms = SumTree::default();
2811        let mut old_expanded_hunks = HashSet::default();
2812        let mut output_edits = Vec::new();
2813        let mut output_delta = 0_isize;
2814        let mut at_transform_boundary = true;
2815        let mut end_of_current_insert = None;
2816
2817        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2818        while let Some(edit) = excerpt_edits.next() {
2819            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2820            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2821                excerpts.prev(&());
2822            }
2823
2824            // Keep any transforms that are before the edit.
2825            if at_transform_boundary {
2826                at_transform_boundary = false;
2827                let transforms_before_edit =
2828                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2829                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2830                if let Some(transform) = old_diff_transforms.item() {
2831                    if old_diff_transforms.end(&()).0 == edit.old.start
2832                        && old_diff_transforms.start().0 < edit.old.start
2833                    {
2834                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2835                        old_diff_transforms.next(&());
2836                    }
2837                }
2838            }
2839
2840            // Compute the start of the edit in output coordinates.
2841            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2842            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2843            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2844
2845            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2846                &edit,
2847                &mut excerpts,
2848                &mut old_diff_transforms,
2849                &mut new_diff_transforms,
2850                &mut end_of_current_insert,
2851                &mut old_expanded_hunks,
2852                &snapshot,
2853                change_kind,
2854            );
2855
2856            // Compute the end of the edit in output coordinates.
2857            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2858            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2859            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2860            let edit_new_end =
2861                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2862            let output_edit = Edit {
2863                old: edit_old_start..edit_old_end,
2864                new: edit_new_start..edit_new_end,
2865            };
2866
2867            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2868            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2869            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2870                output_edits.push(output_edit);
2871            }
2872
2873            // If this is the last edit that intersects the current diff transform,
2874            // then recreate the content up to the end of this transform, to prepare
2875            // for reusing additional slices of the old transforms.
2876            if excerpt_edits.peek().map_or(true, |next_edit| {
2877                next_edit.old.start >= old_diff_transforms.end(&()).0
2878            }) {
2879                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2880                    && match old_diff_transforms.item() {
2881                        Some(DiffTransform::BufferContent {
2882                            inserted_hunk_info: Some(hunk),
2883                            ..
2884                        }) => excerpts.item().is_some_and(|excerpt| {
2885                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2886                        }),
2887                        _ => true,
2888                    };
2889
2890                let mut excerpt_offset = edit.new.end;
2891                if !keep_next_old_transform {
2892                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2893                    old_diff_transforms.next(&());
2894                }
2895
2896                old_expanded_hunks.clear();
2897                self.push_buffer_content_transform(
2898                    &snapshot,
2899                    &mut new_diff_transforms,
2900                    excerpt_offset,
2901                    end_of_current_insert,
2902                );
2903                at_transform_boundary = true;
2904            }
2905        }
2906
2907        // Keep any transforms that are after the last edit.
2908        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2909
2910        // Ensure there's always at least one buffer content transform.
2911        if new_diff_transforms.is_empty() {
2912            new_diff_transforms.push(
2913                DiffTransform::BufferContent {
2914                    summary: Default::default(),
2915                    inserted_hunk_info: None,
2916                },
2917                &(),
2918            );
2919        }
2920
2921        self.subscriptions.publish(output_edits);
2922        drop(old_diff_transforms);
2923        drop(excerpts);
2924        snapshot.diff_transforms = new_diff_transforms;
2925        snapshot.edit_count += 1;
2926
2927        #[cfg(any(test, feature = "test-support"))]
2928        snapshot.check_invariants();
2929    }
2930
2931    #[allow(clippy::too_many_arguments)]
2932    fn recompute_diff_transforms_for_edit(
2933        &self,
2934        edit: &Edit<TypedOffset<Excerpt>>,
2935        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2936        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2937        new_diff_transforms: &mut SumTree<DiffTransform>,
2938        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2939        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2940        snapshot: &MultiBufferSnapshot,
2941        change_kind: DiffChangeKind,
2942    ) -> bool {
2943        log::trace!(
2944            "recomputing diff transform for edit {:?} => {:?}",
2945            edit.old.start.value..edit.old.end.value,
2946            edit.new.start.value..edit.new.end.value
2947        );
2948
2949        // Record which hunks were previously expanded.
2950        while let Some(item) = old_diff_transforms.item() {
2951            if let Some(hunk_info) = item.hunk_info() {
2952                log::trace!(
2953                    "previously expanded hunk at {}",
2954                    old_diff_transforms.start().0
2955                );
2956                old_expanded_hunks.insert(hunk_info);
2957            }
2958            if old_diff_transforms.end(&()).0 > edit.old.end {
2959                break;
2960            }
2961            old_diff_transforms.next(&());
2962        }
2963
2964        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2965        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2966        if old_expanded_hunks.is_empty()
2967            && change_kind == DiffChangeKind::BufferEdited
2968            && !all_diff_hunks_expanded
2969        {
2970            return false;
2971        }
2972
2973        // Visit each excerpt that intersects the edit.
2974        let mut did_expand_hunks = false;
2975        while let Some(excerpt) = excerpts.item() {
2976            // Recompute the expanded hunks in the portion of the excerpt that
2977            // intersects the edit.
2978            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2979                let buffer = &excerpt.buffer;
2980                let excerpt_start = *excerpts.start();
2981                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2982                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2983                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2984                let edit_buffer_start =
2985                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2986                let edit_buffer_end =
2987                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2988                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2989                let edit_anchor_range =
2990                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2991
2992                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2993                    if hunk.is_created_file() && !all_diff_hunks_expanded {
2994                        continue;
2995                    }
2996
2997                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2998                    if hunk_buffer_range.start < excerpt_buffer_start {
2999                        log::trace!("skipping hunk that starts before excerpt");
3000                        continue;
3001                    }
3002
3003                    let hunk_info = DiffTransformHunkInfo {
3004                        excerpt_id: excerpt.id,
3005                        hunk_start_anchor: hunk.buffer_range.start,
3006                        hunk_secondary_status: hunk.secondary_status,
3007                    };
3008
3009                    let hunk_excerpt_start = excerpt_start
3010                        + ExcerptOffset::new(
3011                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3012                        );
3013                    let hunk_excerpt_end = excerpt_end.min(
3014                        excerpt_start
3015                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3016                    );
3017
3018                    self.push_buffer_content_transform(
3019                        snapshot,
3020                        new_diff_transforms,
3021                        hunk_excerpt_start,
3022                        *end_of_current_insert,
3023                    );
3024
3025                    // For every existing hunk, determine if it was previously expanded
3026                    // and if it should currently be expanded.
3027                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3028                    let should_expand_hunk = match &change_kind {
3029                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3030                            was_previously_expanded || all_diff_hunks_expanded
3031                        }
3032                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3033                            let intersects = hunk_buffer_range.is_empty()
3034                                || hunk_buffer_range.end > edit_buffer_start;
3035                            if *expand {
3036                                intersects || was_previously_expanded || all_diff_hunks_expanded
3037                            } else {
3038                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3039                            }
3040                        }
3041                        _ => was_previously_expanded || all_diff_hunks_expanded,
3042                    };
3043
3044                    if should_expand_hunk {
3045                        did_expand_hunks = true;
3046                        log::trace!(
3047                            "expanding hunk {:?}, excerpt:{:?}",
3048                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3049                            excerpt.id
3050                        );
3051
3052                        if !hunk.diff_base_byte_range.is_empty()
3053                            && hunk_buffer_range.start >= edit_buffer_start
3054                            && hunk_buffer_range.start <= excerpt_buffer_end
3055                        {
3056                            let base_text = diff.base_text();
3057                            let mut text_cursor =
3058                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3059                            let mut base_text_summary =
3060                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3061
3062                            let mut has_trailing_newline = false;
3063                            if base_text_summary.last_line_chars > 0 {
3064                                base_text_summary += TextSummary::newline();
3065                                has_trailing_newline = true;
3066                            }
3067
3068                            new_diff_transforms.push(
3069                                DiffTransform::DeletedHunk {
3070                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3071                                    summary: base_text_summary,
3072                                    buffer_id: excerpt.buffer_id,
3073                                    hunk_info,
3074                                    has_trailing_newline,
3075                                },
3076                                &(),
3077                            );
3078                        }
3079
3080                        if !hunk_buffer_range.is_empty() {
3081                            *end_of_current_insert =
3082                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3083                        }
3084                    }
3085                }
3086            }
3087
3088            if excerpts.end(&()) <= edit.new.end {
3089                excerpts.next(&());
3090            } else {
3091                break;
3092            }
3093        }
3094
3095        did_expand_hunks || !old_expanded_hunks.is_empty()
3096    }
3097
3098    fn append_diff_transforms(
3099        &self,
3100        new_transforms: &mut SumTree<DiffTransform>,
3101        subtree: SumTree<DiffTransform>,
3102    ) {
3103        if let Some(DiffTransform::BufferContent {
3104            inserted_hunk_info,
3105            summary,
3106        }) = subtree.first()
3107        {
3108            if self.extend_last_buffer_content_transform(
3109                new_transforms,
3110                *inserted_hunk_info,
3111                *summary,
3112            ) {
3113                let mut cursor = subtree.cursor::<()>(&());
3114                cursor.next(&());
3115                cursor.next(&());
3116                new_transforms.append(cursor.suffix(&()), &());
3117                return;
3118            }
3119        }
3120        new_transforms.append(subtree, &());
3121    }
3122
3123    fn push_diff_transform(
3124        &self,
3125        new_transforms: &mut SumTree<DiffTransform>,
3126        transform: DiffTransform,
3127    ) {
3128        if let DiffTransform::BufferContent {
3129            inserted_hunk_info: inserted_hunk_anchor,
3130            summary,
3131        } = transform
3132        {
3133            if self.extend_last_buffer_content_transform(
3134                new_transforms,
3135                inserted_hunk_anchor,
3136                summary,
3137            ) {
3138                return;
3139            }
3140        }
3141        new_transforms.push(transform, &());
3142    }
3143
3144    fn push_buffer_content_transform(
3145        &self,
3146        old_snapshot: &MultiBufferSnapshot,
3147        new_transforms: &mut SumTree<DiffTransform>,
3148        end_offset: ExcerptOffset,
3149        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3150    ) {
3151        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3152            (end_offset.min(insertion_end_offset), Some(hunk_info))
3153        });
3154        let unchanged_region = [(end_offset, None)];
3155
3156        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3157        {
3158            let start_offset = new_transforms.summary().excerpt_len();
3159            if end_offset <= start_offset {
3160                continue;
3161            }
3162            let summary_to_add = old_snapshot
3163                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3164
3165            if !self.extend_last_buffer_content_transform(
3166                new_transforms,
3167                inserted_hunk_info,
3168                summary_to_add,
3169            ) {
3170                new_transforms.push(
3171                    DiffTransform::BufferContent {
3172                        summary: summary_to_add,
3173                        inserted_hunk_info,
3174                    },
3175                    &(),
3176                )
3177            }
3178        }
3179    }
3180
3181    fn extend_last_buffer_content_transform(
3182        &self,
3183        new_transforms: &mut SumTree<DiffTransform>,
3184        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3185        summary_to_add: TextSummary,
3186    ) -> bool {
3187        let mut did_extend = false;
3188        new_transforms.update_last(
3189            |last_transform| {
3190                if let DiffTransform::BufferContent {
3191                    summary,
3192                    inserted_hunk_info: inserted_hunk_anchor,
3193                } = last_transform
3194                {
3195                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3196                        *summary += summary_to_add;
3197                        did_extend = true;
3198                    }
3199                }
3200            },
3201            &(),
3202        );
3203        did_extend
3204    }
3205}
3206
3207#[cfg(any(test, feature = "test-support"))]
3208impl MultiBuffer {
3209    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3210        let buffer = cx.new(|cx| Buffer::local(text, cx));
3211        cx.new(|cx| Self::singleton(buffer, cx))
3212    }
3213
3214    pub fn build_multi<const COUNT: usize>(
3215        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3216        cx: &mut gpui::App,
3217    ) -> Entity<Self> {
3218        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3219        for (text, ranges) in excerpts {
3220            let buffer = cx.new(|cx| Buffer::local(text, cx));
3221            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3222                context: range,
3223                primary: None,
3224            });
3225            multi.update(cx, |multi, cx| {
3226                multi.push_excerpts(buffer, excerpt_ranges, cx)
3227            });
3228        }
3229
3230        multi
3231    }
3232
3233    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3234        cx.new(|cx| Self::singleton(buffer, cx))
3235    }
3236
3237    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3238        cx.new(|cx| {
3239            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3240            let mutation_count = rng.gen_range(1..=5);
3241            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3242            multibuffer
3243        })
3244    }
3245
3246    pub fn randomly_edit(
3247        &mut self,
3248        rng: &mut impl rand::Rng,
3249        edit_count: usize,
3250        cx: &mut Context<Self>,
3251    ) {
3252        use util::RandomCharIter;
3253
3254        let snapshot = self.read(cx);
3255        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3256        let mut last_end = None;
3257        for _ in 0..edit_count {
3258            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3259                break;
3260            }
3261
3262            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3263            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3264            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3265            last_end = Some(end);
3266
3267            let mut range = start..end;
3268            if rng.gen_bool(0.2) {
3269                mem::swap(&mut range.start, &mut range.end);
3270            }
3271
3272            let new_text_len = rng.gen_range(0..10);
3273            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3274
3275            edits.push((range, new_text.into()));
3276        }
3277        log::info!("mutating multi-buffer with {:?}", edits);
3278        drop(snapshot);
3279
3280        self.edit(edits, None, cx);
3281    }
3282
3283    pub fn randomly_edit_excerpts(
3284        &mut self,
3285        rng: &mut impl rand::Rng,
3286        mutation_count: usize,
3287        cx: &mut Context<Self>,
3288    ) {
3289        use rand::prelude::*;
3290        use std::env;
3291        use util::RandomCharIter;
3292
3293        let max_excerpts = env::var("MAX_EXCERPTS")
3294            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3295            .unwrap_or(5);
3296
3297        let mut buffers = Vec::new();
3298        for _ in 0..mutation_count {
3299            if rng.gen_bool(0.05) {
3300                log::info!("Clearing multi-buffer");
3301                self.clear(cx);
3302                continue;
3303            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3304                let ids = self.excerpt_ids();
3305                let mut excerpts = HashSet::default();
3306                for _ in 0..rng.gen_range(0..ids.len()) {
3307                    excerpts.extend(ids.choose(rng).copied());
3308                }
3309
3310                let line_count = rng.gen_range(0..5);
3311
3312                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3313
3314                self.expand_excerpts(
3315                    excerpts.iter().cloned(),
3316                    line_count,
3317                    ExpandExcerptDirection::UpAndDown,
3318                    cx,
3319                );
3320                continue;
3321            }
3322
3323            let excerpt_ids = self.excerpt_ids();
3324            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3325                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3326                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3327                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3328                    let buffer = buffers.last().unwrap().read(cx);
3329                    log::info!(
3330                        "Creating new buffer {} with text: {:?}",
3331                        buffer.remote_id(),
3332                        buffer.text()
3333                    );
3334                    buffers.last().unwrap().clone()
3335                } else {
3336                    self.buffers
3337                        .borrow()
3338                        .values()
3339                        .choose(rng)
3340                        .unwrap()
3341                        .buffer
3342                        .clone()
3343                };
3344
3345                let buffer = buffer_handle.read(cx);
3346                let buffer_text = buffer.text();
3347                let ranges = (0..rng.gen_range(0..5))
3348                    .map(|_| {
3349                        let end_ix =
3350                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3351                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3352                        ExcerptRange {
3353                            context: start_ix..end_ix,
3354                            primary: None,
3355                        }
3356                    })
3357                    .collect::<Vec<_>>();
3358                log::info!(
3359                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3360                    buffer_handle.read(cx).remote_id(),
3361                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3362                    ranges
3363                        .iter()
3364                        .map(|r| &buffer_text[r.context.clone()])
3365                        .collect::<Vec<_>>()
3366                );
3367
3368                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3369                log::info!("Inserted with ids: {:?}", excerpt_id);
3370            } else {
3371                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3372                let mut excerpts_to_remove = excerpt_ids
3373                    .choose_multiple(rng, remove_count)
3374                    .cloned()
3375                    .collect::<Vec<_>>();
3376                let snapshot = self.snapshot.borrow();
3377                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3378                drop(snapshot);
3379                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3380                self.remove_excerpts(excerpts_to_remove, cx);
3381            }
3382        }
3383    }
3384
3385    pub fn randomly_mutate(
3386        &mut self,
3387        rng: &mut impl rand::Rng,
3388        mutation_count: usize,
3389        cx: &mut Context<Self>,
3390    ) {
3391        use rand::prelude::*;
3392
3393        if rng.gen_bool(0.7) || self.singleton {
3394            let buffer = self
3395                .buffers
3396                .borrow()
3397                .values()
3398                .choose(rng)
3399                .map(|state| state.buffer.clone());
3400
3401            if let Some(buffer) = buffer {
3402                buffer.update(cx, |buffer, cx| {
3403                    if rng.gen() {
3404                        buffer.randomly_edit(rng, mutation_count, cx);
3405                    } else {
3406                        buffer.randomly_undo_redo(rng, cx);
3407                    }
3408                });
3409            } else {
3410                self.randomly_edit(rng, mutation_count, cx);
3411            }
3412        } else {
3413            self.randomly_edit_excerpts(rng, mutation_count, cx);
3414        }
3415
3416        self.check_invariants(cx);
3417    }
3418
3419    fn check_invariants(&self, cx: &App) {
3420        self.read(cx).check_invariants();
3421    }
3422}
3423
3424impl EventEmitter<Event> for MultiBuffer {}
3425
3426impl MultiBufferSnapshot {
3427    pub fn text(&self) -> String {
3428        self.chunks(0..self.len(), false)
3429            .map(|chunk| chunk.text)
3430            .collect()
3431    }
3432
3433    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3434        self.reversed_chunks_in_range(0..position.to_offset(self))
3435            .flat_map(|c| c.chars().rev())
3436    }
3437
3438    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3439        let mut cursor = self.cursor::<usize>();
3440        cursor.seek(&range.end);
3441        let current_chunks = cursor.region().as_ref().map(|region| {
3442            let start_overshoot = range.start.saturating_sub(region.range.start);
3443            let end_overshoot = range.end - region.range.start;
3444            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3445            let start = region.buffer_range.start + start_overshoot;
3446            region.buffer.reversed_chunks_in_range(start..end)
3447        });
3448        ReversedMultiBufferChunks {
3449            cursor,
3450            current_chunks,
3451            start: range.start,
3452            offset: range.end,
3453        }
3454    }
3455
3456    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3457        let offset = position.to_offset(self);
3458        self.text_for_range(offset..self.len())
3459            .flat_map(|chunk| chunk.chars())
3460    }
3461
3462    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3463        self.chunks(range, false).map(|chunk| chunk.text)
3464    }
3465
3466    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3467        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3468            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3469    }
3470
3471    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3472    where
3473        T: ToOffset,
3474    {
3475        let position = position.to_offset(self);
3476        position == self.clip_offset(position, Bias::Left)
3477            && self
3478                .bytes_in_range(position..self.len())
3479                .flatten()
3480                .copied()
3481                .take(needle.len())
3482                .eq(needle.bytes())
3483    }
3484
3485    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3486        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3487    }
3488
3489    pub fn diff_hunks_in_range<T: ToPoint>(
3490        &self,
3491        range: Range<T>,
3492    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3493        let query_range = range.start.to_point(self)..range.end.to_point(self);
3494        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3495            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
3496                log::debug!("no diff found for {:?}", buffer.remote_id());
3497                return None;
3498            };
3499            let buffer_start = buffer.anchor_before(buffer_range.start);
3500            let buffer_end = buffer.anchor_after(buffer_range.end);
3501            Some(
3502                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3503                    .filter_map(|hunk| {
3504                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3505                            return None;
3506                        }
3507                        Some((hunk.range.clone(), hunk))
3508                    }),
3509            )
3510        })
3511        .filter_map(move |(range, hunk, excerpt)| {
3512            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3513            {
3514                return None;
3515            }
3516            let end_row = if range.end.column == 0 {
3517                range.end.row
3518            } else {
3519                range.end.row + 1
3520            };
3521            Some(MultiBufferDiffHunk {
3522                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3523                buffer_id: excerpt.buffer_id,
3524                excerpt_id: excerpt.id,
3525                buffer_range: hunk.buffer_range.clone(),
3526                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3527                secondary_status: hunk.secondary_status,
3528            })
3529        })
3530    }
3531
3532    pub fn excerpt_ids_for_range<T: ToOffset>(
3533        &self,
3534        range: Range<T>,
3535    ) -> impl Iterator<Item = ExcerptId> + '_ {
3536        let range = range.start.to_offset(self)..range.end.to_offset(self);
3537        let mut cursor = self.cursor::<usize>();
3538        cursor.seek(&range.start);
3539        std::iter::from_fn(move || {
3540            let region = cursor.region()?;
3541            if region.range.start >= range.end {
3542                return None;
3543            }
3544            cursor.next_excerpt();
3545            Some(region.excerpt.id)
3546        })
3547    }
3548
3549    pub fn buffer_ids_for_range<T: ToOffset>(
3550        &self,
3551        range: Range<T>,
3552    ) -> impl Iterator<Item = BufferId> + '_ {
3553        let range = range.start.to_offset(self)..range.end.to_offset(self);
3554        let mut cursor = self.cursor::<usize>();
3555        cursor.seek(&range.start);
3556        std::iter::from_fn(move || {
3557            let region = cursor.region()?;
3558            if region.range.start > range.end
3559                || region.range.start == range.end && region.range.start > range.start
3560            {
3561                return None;
3562            }
3563            cursor.next_excerpt();
3564            Some(region.excerpt.buffer_id)
3565        })
3566    }
3567
3568    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3569        &self,
3570        ranges: impl Iterator<Item = Range<T>>,
3571    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3572        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3573    }
3574
3575    pub fn range_to_buffer_ranges<T: ToOffset>(
3576        &self,
3577        range: Range<T>,
3578    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3579        let start = range.start.to_offset(&self);
3580        let end = range.end.to_offset(&self);
3581
3582        let mut cursor = self.cursor::<usize>();
3583        cursor.seek(&start);
3584
3585        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3586        while let Some(region) = cursor.region() {
3587            if region.range.start > end {
3588                break;
3589            }
3590            if region.is_main_buffer {
3591                let start_overshoot = start.saturating_sub(region.range.start);
3592                let end_overshoot = end.saturating_sub(region.range.start);
3593                let start = region
3594                    .buffer_range
3595                    .end
3596                    .min(region.buffer_range.start + start_overshoot);
3597                let end = region
3598                    .buffer_range
3599                    .end
3600                    .min(region.buffer_range.start + end_overshoot);
3601                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3602                    *excerpt_id == region.excerpt.id && prev_range.end == start
3603                }) {
3604                    prev.1.end = end;
3605                } else {
3606                    result.push((region.buffer, start..end, region.excerpt.id));
3607                }
3608            }
3609            cursor.next();
3610        }
3611        result
3612    }
3613
3614    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3615        &self,
3616        range: Range<T>,
3617    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3618        let start = range.start.to_offset(&self);
3619        let end = range.end.to_offset(&self);
3620
3621        let mut cursor = self.cursor::<usize>();
3622        cursor.seek(&start);
3623
3624        std::iter::from_fn(move || {
3625            let region = cursor.region()?;
3626            if region.range.start > end {
3627                return None;
3628            }
3629            let start_overshoot = start.saturating_sub(region.range.start);
3630            let end_overshoot = end.saturating_sub(region.range.start);
3631            let start = region
3632                .buffer_range
3633                .end
3634                .min(region.buffer_range.start + start_overshoot);
3635            let end = region
3636                .buffer_range
3637                .end
3638                .min(region.buffer_range.start + end_overshoot);
3639
3640            let region_excerpt_id = region.excerpt.id;
3641            let deleted_hunk_anchor = if region.is_main_buffer {
3642                None
3643            } else {
3644                Some(self.anchor_before(region.range.start))
3645            };
3646            let result = (
3647                region.buffer,
3648                start..end,
3649                region_excerpt_id,
3650                deleted_hunk_anchor,
3651            );
3652            cursor.next();
3653            Some(result)
3654        })
3655    }
3656
3657    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3658    /// coordinates.
3659    ///
3660    /// The given callback will be called for every excerpt intersecting the given range. It will
3661    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3662    /// The callback should return an iterator of metadata items from that buffer, each paired
3663    /// with a buffer range.
3664    ///
3665    /// The returned iterator yields each of these metadata items, paired with its range in
3666    /// multi-buffer coordinates.
3667    fn lift_buffer_metadata<'a, D, M, I>(
3668        &'a self,
3669        query_range: Range<D>,
3670        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3671    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3672    where
3673        I: Iterator<Item = (Range<D>, M)> + 'a,
3674        D: TextDimension + Ord + Sub<D, Output = D>,
3675    {
3676        let max_position = D::from_text_summary(&self.text_summary());
3677        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3678        let mut cursor = self.cursor::<D>();
3679
3680        // Find the excerpt and buffer offset where the given range ends.
3681        cursor.seek(&query_range.end);
3682        let mut range_end = None;
3683        while let Some(region) = cursor.region() {
3684            if region.is_main_buffer {
3685                let mut buffer_end = region.buffer_range.start;
3686                let overshoot = if query_range.end > region.range.start {
3687                    query_range.end - region.range.start
3688                } else {
3689                    D::default()
3690                };
3691                buffer_end.add_assign(&overshoot);
3692                range_end = Some((region.excerpt.id, buffer_end));
3693                break;
3694            }
3695            cursor.next();
3696        }
3697
3698        cursor.seek(&query_range.start);
3699
3700        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3701            if region.range.start > D::zero(&()) {
3702                cursor.prev()
3703            }
3704        }
3705
3706        iter::from_fn(move || loop {
3707            let excerpt = cursor.excerpt()?;
3708
3709            // If we have already retrieved metadata for this excerpt, continue to use it.
3710            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3711                .as_mut()
3712                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3713            {
3714                Some(metadata)
3715            }
3716            // Otherwise, compute the intersection of the input range with the excerpt's range,
3717            // and retrieve the metadata for the resulting range.
3718            else {
3719                let region = cursor.region()?;
3720                let mut buffer_start;
3721                if region.is_main_buffer {
3722                    buffer_start = region.buffer_range.start;
3723                    if query_range.start > region.range.start {
3724                        let overshoot = query_range.start - region.range.start;
3725                        buffer_start.add_assign(&overshoot);
3726                    }
3727                    buffer_start = buffer_start.min(region.buffer_range.end);
3728                } else {
3729                    buffer_start = cursor.main_buffer_position()?;
3730                };
3731                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3732                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3733                    if excerpt.id == end_excerpt_id {
3734                        buffer_end = buffer_end.min(end_buffer_offset);
3735                    }
3736                }
3737
3738                if let Some(iterator) =
3739                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3740                {
3741                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3742                } else {
3743                    None
3744                }
3745            };
3746
3747            // Visit each metadata item.
3748            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3749            {
3750                // Find the multibuffer regions that contain the start and end of
3751                // the metadata item's range.
3752                if metadata_buffer_range.start > D::default() {
3753                    while let Some(region) = cursor.region() {
3754                        if region.is_main_buffer
3755                            && (region.buffer_range.end >= metadata_buffer_range.start
3756                                || cursor.is_at_end_of_excerpt())
3757                        {
3758                            break;
3759                        }
3760                        cursor.next();
3761                    }
3762                }
3763                let start_region = cursor.region()?;
3764                while let Some(region) = cursor.region() {
3765                    if region.is_main_buffer
3766                        && (region.buffer_range.end > metadata_buffer_range.end
3767                            || cursor.is_at_end_of_excerpt())
3768                    {
3769                        break;
3770                    }
3771                    cursor.next();
3772                }
3773                let end_region = cursor.region();
3774
3775                // Convert the metadata item's range into multibuffer coordinates.
3776                let mut start_position = start_region.range.start;
3777                let region_buffer_start = start_region.buffer_range.start;
3778                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3779                {
3780                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3781                    start_position = start_position.min(start_region.range.end);
3782                }
3783
3784                let mut end_position = max_position;
3785                if let Some(end_region) = &end_region {
3786                    end_position = end_region.range.start;
3787                    debug_assert!(end_region.is_main_buffer);
3788                    let region_buffer_start = end_region.buffer_range.start;
3789                    if metadata_buffer_range.end > region_buffer_start {
3790                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3791                    }
3792                    end_position = end_position.min(end_region.range.end);
3793                }
3794
3795                if start_position <= query_range.end && end_position >= query_range.start {
3796                    return Some((start_position..end_position, metadata, excerpt));
3797                }
3798            }
3799            // When there are no more metadata items for this excerpt, move to the next excerpt.
3800            else {
3801                current_excerpt_metadata.take();
3802                cursor.next_excerpt();
3803            }
3804        })
3805    }
3806
3807    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3808        let offset = position.to_offset(self);
3809
3810        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3811        cursor.seek(&DimensionPair {
3812            key: offset,
3813            value: None,
3814        });
3815        cursor.seek_to_start_of_current_excerpt();
3816        let excerpt = cursor.excerpt()?;
3817
3818        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3819        let current_position = self
3820            .anchor_before(offset)
3821            .text_anchor
3822            .to_offset(&excerpt.buffer);
3823        let excerpt_end = excerpt
3824            .buffer
3825            .anchor_before(excerpt_end.min(current_position));
3826
3827        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3828            for hunk in diff.hunks_intersecting_range_rev(
3829                excerpt.range.context.start..excerpt_end,
3830                &excerpt.buffer,
3831            ) {
3832                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3833                if hunk_end >= current_position {
3834                    continue;
3835                }
3836                let start =
3837                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3838                        .to_point(&self);
3839                return Some(MultiBufferRow(start.row));
3840            }
3841        }
3842
3843        loop {
3844            cursor.prev_excerpt();
3845            let excerpt = cursor.excerpt()?;
3846
3847            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3848                continue;
3849            };
3850            let mut hunks =
3851                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3852            let Some(hunk) = hunks.next() else {
3853                continue;
3854            };
3855            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3856                .to_point(&self);
3857            return Some(MultiBufferRow(start.row));
3858        }
3859    }
3860
3861    pub fn has_diff_hunks(&self) -> bool {
3862        self.diffs.values().any(|diff| !diff.is_empty())
3863    }
3864
3865    pub fn surrounding_word<T: ToOffset>(
3866        &self,
3867        start: T,
3868        for_completion: bool,
3869    ) -> (Range<usize>, Option<CharKind>) {
3870        let mut start = start.to_offset(self);
3871        let mut end = start;
3872        let mut next_chars = self.chars_at(start).peekable();
3873        let mut prev_chars = self.reversed_chars_at(start).peekable();
3874
3875        let classifier = self
3876            .char_classifier_at(start)
3877            .for_completion(for_completion);
3878
3879        let word_kind = cmp::max(
3880            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3881            next_chars.peek().copied().map(|c| classifier.kind(c)),
3882        );
3883
3884        for ch in prev_chars {
3885            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3886                start -= ch.len_utf8();
3887            } else {
3888                break;
3889            }
3890        }
3891
3892        for ch in next_chars {
3893            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3894                end += ch.len_utf8();
3895            } else {
3896                break;
3897            }
3898        }
3899
3900        (start..end, word_kind)
3901    }
3902
3903    pub fn is_singleton(&self) -> bool {
3904        self.singleton
3905    }
3906
3907    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3908        if self.singleton {
3909            self.excerpts
3910                .iter()
3911                .next()
3912                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3913        } else {
3914            None
3915        }
3916    }
3917
3918    pub fn len(&self) -> usize {
3919        self.diff_transforms.summary().output.len
3920    }
3921
3922    pub fn is_empty(&self) -> bool {
3923        self.excerpts.summary().text.len == 0
3924    }
3925
3926    pub fn widest_line_number(&self) -> u32 {
3927        self.excerpts.summary().widest_line_number + 1
3928    }
3929
3930    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3931        let range = range.start.to_offset(self)..range.end.to_offset(self);
3932        let mut excerpts = self.cursor::<usize>();
3933        excerpts.seek(&range.start);
3934
3935        let mut chunk;
3936        let mut has_trailing_newline;
3937        let excerpt_bytes;
3938        if let Some(region) = excerpts.region() {
3939            let mut bytes = region.buffer.bytes_in_range(
3940                region.buffer_range.start + range.start - region.range.start
3941                    ..(region.buffer_range.start + range.end - region.range.start)
3942                        .min(region.buffer_range.end),
3943            );
3944            chunk = bytes.next().unwrap_or(&[][..]);
3945            excerpt_bytes = Some(bytes);
3946            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3947            if chunk.is_empty() && has_trailing_newline {
3948                chunk = b"\n";
3949                has_trailing_newline = false;
3950            }
3951        } else {
3952            chunk = &[][..];
3953            excerpt_bytes = None;
3954            has_trailing_newline = false;
3955        };
3956
3957        MultiBufferBytes {
3958            range,
3959            cursor: excerpts,
3960            excerpt_bytes,
3961            has_trailing_newline,
3962            chunk,
3963        }
3964    }
3965
3966    pub fn reversed_bytes_in_range<T: ToOffset>(
3967        &self,
3968        range: Range<T>,
3969    ) -> ReversedMultiBufferBytes {
3970        let range = range.start.to_offset(self)..range.end.to_offset(self);
3971        let mut chunks = self.reversed_chunks_in_range(range.clone());
3972        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3973        ReversedMultiBufferBytes {
3974            range,
3975            chunks,
3976            chunk,
3977        }
3978    }
3979
3980    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
3981        let mut cursor = self.cursor::<Point>();
3982        cursor.seek(&Point::new(start_row.0, 0));
3983        let mut result = MultiBufferRows {
3984            point: Point::new(0, 0),
3985            is_empty: self.excerpts.is_empty(),
3986            cursor,
3987        };
3988        result.seek(start_row);
3989        result
3990    }
3991
3992    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
3993        let mut chunks = MultiBufferChunks {
3994            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3995            range: 0..0,
3996            excerpts: self.excerpts.cursor(&()),
3997            diff_transforms: self.diff_transforms.cursor(&()),
3998            diffs: &self.diffs,
3999            diff_base_chunks: None,
4000            excerpt_chunks: None,
4001            buffer_chunk: None,
4002            language_aware,
4003        };
4004        let range = range.start.to_offset(self)..range.end.to_offset(self);
4005        chunks.seek(range);
4006        chunks
4007    }
4008
4009    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4010        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4011    }
4012
4013    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4014        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4015    }
4016
4017    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4018        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4019    }
4020
4021    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4022        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4023            buffer.clip_point_utf16(Unclipped(point), bias)
4024        })
4025    }
4026
4027    pub fn offset_to_point(&self, offset: usize) -> Point {
4028        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4029    }
4030
4031    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4032        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4033    }
4034
4035    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4036        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4037    }
4038
4039    pub fn point_to_offset(&self, point: Point) -> usize {
4040        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4041    }
4042
4043    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4044        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4045    }
4046
4047    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4048        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4049    }
4050
4051    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4052        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4053    }
4054
4055    fn clip_dimension<D>(
4056        &self,
4057        position: D,
4058        bias: Bias,
4059        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4060    ) -> D
4061    where
4062        D: TextDimension + Ord + Sub<D, Output = D>,
4063    {
4064        let mut cursor = self.cursor();
4065        cursor.seek(&position);
4066        if let Some(region) = cursor.region() {
4067            if position >= region.range.end {
4068                return region.range.end;
4069            }
4070            let overshoot = position - region.range.start;
4071            let mut buffer_position = region.buffer_range.start;
4072            buffer_position.add_assign(&overshoot);
4073            let clipped_buffer_position =
4074                clip_buffer_position(&region.buffer, buffer_position, bias);
4075            let mut position = region.range.start;
4076            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4077            position
4078        } else {
4079            D::from_text_summary(&self.text_summary())
4080        }
4081    }
4082
4083    fn convert_dimension<D1, D2>(
4084        &self,
4085        key: D1,
4086        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4087    ) -> D2
4088    where
4089        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4090        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4091    {
4092        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4093        cursor.seek(&DimensionPair { key, value: None });
4094        if let Some(region) = cursor.region() {
4095            if key >= region.range.end.key {
4096                return region.range.end.value.unwrap();
4097            }
4098            let start_key = region.range.start.key;
4099            let start_value = region.range.start.value.unwrap();
4100            let buffer_start_key = region.buffer_range.start.key;
4101            let buffer_start_value = region.buffer_range.start.value.unwrap();
4102            let mut buffer_key = buffer_start_key;
4103            buffer_key.add_assign(&(key - start_key));
4104            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4105            let mut result = start_value;
4106            result.add_assign(&(buffer_value - buffer_start_value));
4107            result
4108        } else {
4109            D2::from_text_summary(&self.text_summary())
4110        }
4111    }
4112
4113    pub fn point_to_buffer_offset<T: ToOffset>(
4114        &self,
4115        point: T,
4116    ) -> Option<(&BufferSnapshot, usize)> {
4117        let offset = point.to_offset(self);
4118        let mut cursor = self.cursor::<usize>();
4119        cursor.seek(&offset);
4120        let region = cursor.region()?;
4121        let overshoot = offset - region.range.start;
4122        let buffer_offset = region.buffer_range.start + overshoot;
4123        Some((region.buffer, buffer_offset))
4124    }
4125
4126    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4127        let mut cursor = self.cursor::<Point>();
4128        cursor.seek(&point);
4129        let region = cursor.region()?;
4130        let overshoot = point - region.range.start;
4131        let buffer_offset = region.buffer_range.start + overshoot;
4132        Some((region.buffer, buffer_offset, region.is_main_buffer))
4133    }
4134
4135    pub fn suggested_indents(
4136        &self,
4137        rows: impl IntoIterator<Item = u32>,
4138        cx: &App,
4139    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4140        let mut result = BTreeMap::new();
4141
4142        let mut rows_for_excerpt = Vec::new();
4143        let mut cursor = self.cursor::<Point>();
4144        let mut rows = rows.into_iter().peekable();
4145        let mut prev_row = u32::MAX;
4146        let mut prev_language_indent_size = IndentSize::default();
4147
4148        while let Some(row) = rows.next() {
4149            cursor.seek(&Point::new(row, 0));
4150            let Some(region) = cursor.region() else {
4151                continue;
4152            };
4153
4154            // Retrieve the language and indent size once for each disjoint region being indented.
4155            let single_indent_size = if row.saturating_sub(1) == prev_row {
4156                prev_language_indent_size
4157            } else {
4158                region
4159                    .buffer
4160                    .language_indent_size_at(Point::new(row, 0), cx)
4161            };
4162            prev_language_indent_size = single_indent_size;
4163            prev_row = row;
4164
4165            let start_buffer_row = region.buffer_range.start.row;
4166            let start_multibuffer_row = region.range.start.row;
4167            let end_multibuffer_row = region.range.end.row;
4168
4169            rows_for_excerpt.push(row);
4170            while let Some(next_row) = rows.peek().copied() {
4171                if end_multibuffer_row > next_row {
4172                    rows_for_excerpt.push(next_row);
4173                    rows.next();
4174                } else {
4175                    break;
4176                }
4177            }
4178
4179            let buffer_rows = rows_for_excerpt
4180                .drain(..)
4181                .map(|row| start_buffer_row + row - start_multibuffer_row);
4182            let buffer_indents = region
4183                .buffer
4184                .suggested_indents(buffer_rows, single_indent_size);
4185            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4186                (
4187                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4188                    indent,
4189                )
4190            });
4191            result.extend(multibuffer_indents);
4192        }
4193
4194        result
4195    }
4196
4197    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4198        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4199            let mut size = buffer.indent_size_for_line(range.start.row);
4200            size.len = size
4201                .len
4202                .min(range.end.column)
4203                .saturating_sub(range.start.column);
4204            size
4205        } else {
4206            IndentSize::spaces(0)
4207        }
4208    }
4209
4210    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4211        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4212            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4213        } else {
4214            LineIndent::spaces(0)
4215        }
4216    }
4217
4218    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4219        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4220
4221        if self.settings_at(0, cx).extend_comment_on_newline {
4222            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4223                let delimiters = language_scope.line_comment_prefixes();
4224                for delimiter in delimiters {
4225                    if *self
4226                        .chars_at(Point::new(row.0, indent.len() as u32))
4227                        .take(delimiter.chars().count())
4228                        .collect::<String>()
4229                        .as_str()
4230                        == **delimiter
4231                    {
4232                        indent.push_str(&delimiter);
4233                        break;
4234                    }
4235                }
4236            }
4237        }
4238
4239        indent
4240    }
4241
4242    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4243    where
4244        T: ToOffset,
4245    {
4246        for char in self.reversed_chars_at(position) {
4247            if !char.is_whitespace() {
4248                return false;
4249            }
4250            if char == '\n' {
4251                return true;
4252            }
4253        }
4254        return true;
4255    }
4256
4257    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4258        while row.0 > 0 {
4259            row.0 -= 1;
4260            if !self.is_line_blank(row) {
4261                return Some(row);
4262            }
4263        }
4264        None
4265    }
4266
4267    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4268        if let Some((_, range)) = self.buffer_line_for_row(row) {
4269            range.end.column - range.start.column
4270        } else {
4271            0
4272        }
4273    }
4274
4275    pub fn buffer_line_for_row(
4276        &self,
4277        row: MultiBufferRow,
4278    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4279        let mut cursor = self.cursor::<Point>();
4280        let point = Point::new(row.0, 0);
4281        cursor.seek(&point);
4282        let region = cursor.region()?;
4283        let overshoot = point.min(region.range.end) - region.range.start;
4284        let buffer_point = region.buffer_range.start + overshoot;
4285        if buffer_point.row > region.buffer_range.end.row {
4286            return None;
4287        }
4288        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4289        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4290            .min(region.buffer_range.end);
4291        Some((region.buffer, line_start..line_end))
4292    }
4293
4294    pub fn max_point(&self) -> Point {
4295        self.text_summary().lines
4296    }
4297
4298    pub fn max_row(&self) -> MultiBufferRow {
4299        MultiBufferRow(self.text_summary().lines.row)
4300    }
4301
4302    pub fn text_summary(&self) -> TextSummary {
4303        self.diff_transforms.summary().output
4304    }
4305
4306    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4307    where
4308        D: TextDimension,
4309        O: ToOffset,
4310    {
4311        let range = range.start.to_offset(self)..range.end.to_offset(self);
4312        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4313        cursor.seek(&range.start, Bias::Right, &());
4314
4315        let Some(first_transform) = cursor.item() else {
4316            return D::from_text_summary(&TextSummary::default());
4317        };
4318
4319        let diff_transform_start = cursor.start().0;
4320        let diff_transform_end = cursor.end(&()).0;
4321        let diff_start = range.start;
4322        let start_overshoot = diff_start - diff_transform_start;
4323        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4324
4325        let mut result = match first_transform {
4326            DiffTransform::BufferContent { .. } => {
4327                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4328                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4329                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4330            }
4331            DiffTransform::DeletedHunk {
4332                buffer_id,
4333                base_text_byte_range,
4334                has_trailing_newline,
4335                ..
4336            } => {
4337                let buffer_start = base_text_byte_range.start + start_overshoot;
4338                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4339                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4340                    panic!("{:?} is in non-existent deleted hunk", range.start)
4341                };
4342
4343                let include_trailing_newline =
4344                    *has_trailing_newline && range.end >= diff_transform_end;
4345                if include_trailing_newline {
4346                    buffer_end -= 1;
4347                }
4348
4349                let mut summary =
4350                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4351
4352                if include_trailing_newline {
4353                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4354                }
4355
4356                summary
4357            }
4358        };
4359        if range.end < diff_transform_end {
4360            return result;
4361        }
4362
4363        cursor.next(&());
4364        result.add_assign(&D::from_text_summary(&cursor.summary(
4365            &range.end,
4366            Bias::Right,
4367            &(),
4368        )));
4369
4370        let Some(last_transform) = cursor.item() else {
4371            return result;
4372        };
4373
4374        let overshoot = range.end - cursor.start().0;
4375        let suffix = match last_transform {
4376            DiffTransform::BufferContent { .. } => {
4377                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4378                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4379            }
4380            DiffTransform::DeletedHunk {
4381                base_text_byte_range,
4382                buffer_id,
4383                has_trailing_newline,
4384                ..
4385            } => {
4386                let buffer_end = base_text_byte_range.start + overshoot;
4387                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4388                    panic!("{:?} is in non-existent deleted hunk", range.end)
4389                };
4390
4391                let mut suffix = base_text
4392                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4393                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4394                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4395                }
4396                suffix
4397            }
4398        };
4399
4400        result.add_assign(&suffix);
4401        result
4402    }
4403
4404    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4405    where
4406        D: TextDimension,
4407    {
4408        // let mut range = range.start..range.end;
4409        let mut summary = D::zero(&());
4410        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4411        cursor.seek(&range.start, Bias::Right, &());
4412        if let Some(excerpt) = cursor.item() {
4413            let mut end_before_newline = cursor.end(&());
4414            if excerpt.has_trailing_newline {
4415                end_before_newline -= ExcerptOffset::new(1);
4416            }
4417
4418            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4419            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4420            let end_in_excerpt =
4421                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4422            summary.add_assign(
4423                &excerpt
4424                    .buffer
4425                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4426            );
4427
4428            if range.end > end_before_newline {
4429                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4430            }
4431
4432            cursor.next(&());
4433        }
4434
4435        if range.end > *cursor.start() {
4436            summary.add_assign(
4437                &cursor
4438                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4439                    .0,
4440            );
4441            if let Some(excerpt) = cursor.item() {
4442                range.end = cmp::max(*cursor.start(), range.end);
4443
4444                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4445                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4446                summary.add_assign(
4447                    &excerpt
4448                        .buffer
4449                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4450                );
4451            }
4452        }
4453
4454        summary
4455    }
4456
4457    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4458    where
4459        D: TextDimension + Ord + Sub<D, Output = D>,
4460    {
4461        self.summaries_for_anchors([anchor])[0]
4462    }
4463
4464    fn resolve_summary_for_anchor<D>(
4465        &self,
4466        anchor: &Anchor,
4467        excerpt_position: D,
4468        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4469    ) -> D
4470    where
4471        D: TextDimension + Ord + Sub<D, Output = D>,
4472    {
4473        loop {
4474            let transform_end_position = diff_transforms.end(&()).0 .0;
4475            let at_transform_end =
4476                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4477            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4478                diff_transforms.next(&());
4479                continue;
4480            }
4481
4482            let mut position = diff_transforms.start().1 .0;
4483            match diff_transforms.item() {
4484                Some(DiffTransform::DeletedHunk {
4485                    buffer_id,
4486                    base_text_byte_range,
4487                    ..
4488                }) => {
4489                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4490                        if let Some(base_text) =
4491                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4492                        {
4493                            if base_text.can_resolve(&diff_base_anchor) {
4494                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4495                                if base_text_offset >= base_text_byte_range.start
4496                                    && base_text_offset <= base_text_byte_range.end
4497                                {
4498                                    let position_in_hunk = base_text
4499                                        .text_summary_for_range::<D, _>(
4500                                            base_text_byte_range.start..base_text_offset,
4501                                        );
4502                                    position.add_assign(&position_in_hunk);
4503                                } else if at_transform_end {
4504                                    diff_transforms.next(&());
4505                                    continue;
4506                                }
4507                            }
4508                        }
4509                    }
4510                }
4511                _ => {
4512                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4513                        diff_transforms.next(&());
4514                        continue;
4515                    }
4516                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4517                    position.add_assign(&overshoot);
4518                }
4519            }
4520
4521            return position;
4522        }
4523    }
4524
4525    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4526        let mut cursor = self
4527            .excerpts
4528            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4529        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4530
4531        cursor.seek(&Some(locator), Bias::Left, &());
4532        if cursor.item().is_none() {
4533            cursor.next(&());
4534        }
4535
4536        let mut position = cursor.start().1;
4537        if let Some(excerpt) = cursor.item() {
4538            if excerpt.id == anchor.excerpt_id {
4539                let excerpt_buffer_start = excerpt
4540                    .buffer
4541                    .offset_for_anchor(&excerpt.range.context.start);
4542                let excerpt_buffer_end =
4543                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4544                let buffer_position = cmp::min(
4545                    excerpt_buffer_end,
4546                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4547                );
4548                if buffer_position > excerpt_buffer_start {
4549                    position.value += buffer_position - excerpt_buffer_start;
4550                }
4551            }
4552        }
4553        position
4554    }
4555
4556    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4557    where
4558        D: TextDimension + Ord + Sub<D, Output = D>,
4559        I: 'a + IntoIterator<Item = &'a Anchor>,
4560    {
4561        let mut anchors = anchors.into_iter().peekable();
4562        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4563        let mut diff_transforms_cursor = self
4564            .diff_transforms
4565            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4566        diff_transforms_cursor.next(&());
4567
4568        let mut summaries = Vec::new();
4569        while let Some(anchor) = anchors.peek() {
4570            let excerpt_id = anchor.excerpt_id;
4571            let excerpt_anchors = iter::from_fn(|| {
4572                let anchor = anchors.peek()?;
4573                if anchor.excerpt_id == excerpt_id {
4574                    Some(anchors.next().unwrap())
4575                } else {
4576                    None
4577                }
4578            });
4579
4580            let locator = self.excerpt_locator_for_id(excerpt_id);
4581            cursor.seek_forward(locator, Bias::Left, &());
4582            if cursor.item().is_none() {
4583                cursor.next(&());
4584            }
4585
4586            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4587            if let Some(excerpt) = cursor.item() {
4588                if excerpt.id != excerpt_id {
4589                    let position = self.resolve_summary_for_anchor(
4590                        &Anchor::min(),
4591                        excerpt_start_position,
4592                        &mut diff_transforms_cursor,
4593                    );
4594                    summaries.extend(excerpt_anchors.map(|_| position));
4595                    continue;
4596                }
4597                let excerpt_buffer_start =
4598                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4599                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4600                for (buffer_summary, anchor) in excerpt
4601                    .buffer
4602                    .summaries_for_anchors_with_payload::<D, _, _>(
4603                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4604                    )
4605                {
4606                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4607                    let mut position = excerpt_start_position;
4608                    if summary > excerpt_buffer_start {
4609                        position.add_assign(&(summary - excerpt_buffer_start));
4610                    }
4611
4612                    if position > diff_transforms_cursor.start().0 .0 {
4613                        diff_transforms_cursor.seek_forward(
4614                            &ExcerptDimension(position),
4615                            Bias::Left,
4616                            &(),
4617                        );
4618                    }
4619
4620                    summaries.push(self.resolve_summary_for_anchor(
4621                        anchor,
4622                        position,
4623                        &mut diff_transforms_cursor,
4624                    ));
4625                }
4626            } else {
4627                diff_transforms_cursor.seek_forward(
4628                    &ExcerptDimension(excerpt_start_position),
4629                    Bias::Left,
4630                    &(),
4631                );
4632                let position = self.resolve_summary_for_anchor(
4633                    &Anchor::max(),
4634                    excerpt_start_position,
4635                    &mut diff_transforms_cursor,
4636                );
4637                summaries.extend(excerpt_anchors.map(|_| position));
4638            }
4639        }
4640
4641        summaries
4642    }
4643
4644    pub fn dimensions_from_points<'a, D>(
4645        &'a self,
4646        points: impl 'a + IntoIterator<Item = Point>,
4647    ) -> impl 'a + Iterator<Item = D>
4648    where
4649        D: TextDimension + Sub<D, Output = D>,
4650    {
4651        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4652        cursor.seek(&DimensionPair {
4653            key: Point::default(),
4654            value: None,
4655        });
4656        let mut points = points.into_iter();
4657        iter::from_fn(move || {
4658            let point = points.next()?;
4659
4660            cursor.seek_forward(&DimensionPair {
4661                key: point,
4662                value: None,
4663            });
4664
4665            if let Some(region) = cursor.region() {
4666                let overshoot = point - region.range.start.key;
4667                let buffer_point = region.buffer_range.start.key + overshoot;
4668                let mut position = region.range.start.value.unwrap();
4669                position.add_assign(
4670                    &region
4671                        .buffer
4672                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4673                );
4674                return Some(position);
4675            } else {
4676                return Some(D::from_text_summary(&self.text_summary()));
4677            }
4678        })
4679    }
4680
4681    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4682    where
4683        I: 'a + IntoIterator<Item = &'a Anchor>,
4684    {
4685        let mut anchors = anchors.into_iter().enumerate().peekable();
4686        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4687        cursor.next(&());
4688
4689        let mut result = Vec::new();
4690
4691        while let Some((_, anchor)) = anchors.peek() {
4692            let old_excerpt_id = anchor.excerpt_id;
4693
4694            // Find the location where this anchor's excerpt should be.
4695            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4696            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4697
4698            if cursor.item().is_none() {
4699                cursor.next(&());
4700            }
4701
4702            let next_excerpt = cursor.item();
4703            let prev_excerpt = cursor.prev_item();
4704
4705            // Process all of the anchors for this excerpt.
4706            while let Some((_, anchor)) = anchors.peek() {
4707                if anchor.excerpt_id != old_excerpt_id {
4708                    break;
4709                }
4710                let (anchor_ix, anchor) = anchors.next().unwrap();
4711                let mut anchor = *anchor;
4712
4713                // Leave min and max anchors unchanged if invalid or
4714                // if the old excerpt still exists at this location
4715                let mut kept_position = next_excerpt
4716                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4717                    || old_excerpt_id == ExcerptId::max()
4718                    || old_excerpt_id == ExcerptId::min();
4719
4720                // If the old excerpt no longer exists at this location, then attempt to
4721                // find an equivalent position for this anchor in an adjacent excerpt.
4722                if !kept_position {
4723                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4724                        if excerpt.contains(&anchor) {
4725                            anchor.excerpt_id = excerpt.id;
4726                            kept_position = true;
4727                            break;
4728                        }
4729                    }
4730                }
4731
4732                // If there's no adjacent excerpt that contains the anchor's position,
4733                // then report that the anchor has lost its position.
4734                if !kept_position {
4735                    anchor = if let Some(excerpt) = next_excerpt {
4736                        let mut text_anchor = excerpt
4737                            .range
4738                            .context
4739                            .start
4740                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4741                        if text_anchor
4742                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4743                            .is_gt()
4744                        {
4745                            text_anchor = excerpt.range.context.end;
4746                        }
4747                        Anchor {
4748                            buffer_id: Some(excerpt.buffer_id),
4749                            excerpt_id: excerpt.id,
4750                            text_anchor,
4751                            diff_base_anchor: None,
4752                        }
4753                    } else if let Some(excerpt) = prev_excerpt {
4754                        let mut text_anchor = excerpt
4755                            .range
4756                            .context
4757                            .end
4758                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4759                        if text_anchor
4760                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4761                            .is_lt()
4762                        {
4763                            text_anchor = excerpt.range.context.start;
4764                        }
4765                        Anchor {
4766                            buffer_id: Some(excerpt.buffer_id),
4767                            excerpt_id: excerpt.id,
4768                            text_anchor,
4769                            diff_base_anchor: None,
4770                        }
4771                    } else if anchor.text_anchor.bias == Bias::Left {
4772                        Anchor::min()
4773                    } else {
4774                        Anchor::max()
4775                    };
4776                }
4777
4778                result.push((anchor_ix, anchor, kept_position));
4779            }
4780        }
4781        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4782        result
4783    }
4784
4785    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4786        self.anchor_at(position, Bias::Left)
4787    }
4788
4789    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4790        self.anchor_at(position, Bias::Right)
4791    }
4792
4793    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4794        let offset = position.to_offset(self);
4795
4796        // Find the given position in the diff transforms. Determine the corresponding
4797        // offset in the excerpts, and whether the position is within a deleted hunk.
4798        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4799        diff_transforms.seek(&offset, Bias::Right, &());
4800
4801        if offset == diff_transforms.start().0 && bias == Bias::Left {
4802            if let Some(prev_item) = diff_transforms.prev_item() {
4803                match prev_item {
4804                    DiffTransform::DeletedHunk { .. } => {
4805                        diff_transforms.prev(&());
4806                    }
4807                    _ => {}
4808                }
4809            }
4810        }
4811        let offset_in_transform = offset - diff_transforms.start().0;
4812        let mut excerpt_offset = diff_transforms.start().1;
4813        let mut diff_base_anchor = None;
4814        if let Some(DiffTransform::DeletedHunk {
4815            buffer_id,
4816            base_text_byte_range,
4817            has_trailing_newline,
4818            ..
4819        }) = diff_transforms.item()
4820        {
4821            let diff = self.diffs.get(buffer_id).expect("missing diff");
4822            if offset_in_transform > base_text_byte_range.len() {
4823                debug_assert!(*has_trailing_newline);
4824                bias = Bias::Right;
4825            } else {
4826                diff_base_anchor = Some(
4827                    diff.base_text()
4828                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4829                );
4830                bias = Bias::Left;
4831            }
4832        } else {
4833            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4834        };
4835
4836        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4837            return Anchor {
4838                buffer_id: Some(buffer_id),
4839                excerpt_id: *excerpt_id,
4840                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4841                diff_base_anchor,
4842            };
4843        }
4844
4845        let mut excerpts = self
4846            .excerpts
4847            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4848        excerpts.seek(&excerpt_offset, Bias::Right, &());
4849        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4850            excerpts.prev(&());
4851        }
4852        if let Some(excerpt) = excerpts.item() {
4853            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4854            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4855                overshoot -= 1;
4856                bias = Bias::Right;
4857            }
4858
4859            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4860            let text_anchor =
4861                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4862            Anchor {
4863                buffer_id: Some(excerpt.buffer_id),
4864                excerpt_id: excerpt.id,
4865                text_anchor,
4866                diff_base_anchor,
4867            }
4868        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4869            Anchor::min()
4870        } else {
4871            Anchor::max()
4872        }
4873    }
4874
4875    /// Returns an anchor for the given excerpt and text anchor,
4876    /// returns None if the excerpt_id is no longer valid.
4877    pub fn anchor_in_excerpt(
4878        &self,
4879        excerpt_id: ExcerptId,
4880        text_anchor: text::Anchor,
4881    ) -> Option<Anchor> {
4882        let locator = self.excerpt_locator_for_id(excerpt_id);
4883        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4884        cursor.seek(locator, Bias::Left, &());
4885        if let Some(excerpt) = cursor.item() {
4886            if excerpt.id == excerpt_id {
4887                let text_anchor = excerpt.clip_anchor(text_anchor);
4888                drop(cursor);
4889                return Some(Anchor {
4890                    buffer_id: Some(excerpt.buffer_id),
4891                    excerpt_id,
4892                    text_anchor,
4893                    diff_base_anchor: None,
4894                });
4895            }
4896        }
4897        None
4898    }
4899
4900    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4901        Some(self.excerpt(excerpt_id)?.range.context.clone())
4902    }
4903
4904    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4905        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4906            true
4907        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4908            excerpt.buffer.can_resolve(&anchor.text_anchor)
4909        } else {
4910            false
4911        }
4912    }
4913
4914    pub fn excerpts(
4915        &self,
4916    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4917        self.excerpts
4918            .iter()
4919            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4920    }
4921
4922    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4923        let excerpts = self.excerpts.cursor(&());
4924        let diff_transforms = self.diff_transforms.cursor(&());
4925        MultiBufferCursor {
4926            excerpts,
4927            diff_transforms,
4928            diffs: &self.diffs,
4929            cached_region: None,
4930        }
4931    }
4932
4933    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4934        let start_locator = self.excerpt_locator_for_id(id);
4935        let mut excerpts = self
4936            .excerpts
4937            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4938        excerpts.seek(&Some(start_locator), Bias::Left, &());
4939        excerpts.prev(&());
4940
4941        let mut diff_transforms = self
4942            .diff_transforms
4943            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4944        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4945        if diff_transforms.end(&()).1 < excerpts.start().1 {
4946            diff_transforms.next(&());
4947        }
4948
4949        let excerpt = excerpts.item()?;
4950        Some(MultiBufferExcerpt {
4951            excerpt,
4952            offset: diff_transforms.start().0 .0,
4953            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4954            excerpt_offset: excerpts.start().1.clone(),
4955            diff_transforms,
4956        })
4957    }
4958
4959    pub fn excerpt_boundaries_in_range<R, T>(
4960        &self,
4961        range: R,
4962    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4963    where
4964        R: RangeBounds<T>,
4965        T: ToOffset,
4966    {
4967        let start_offset;
4968        let start = match range.start_bound() {
4969            Bound::Included(start) => {
4970                start_offset = start.to_offset(self);
4971                Bound::Included(start_offset)
4972            }
4973            Bound::Excluded(_) => {
4974                panic!("not supported")
4975            }
4976            Bound::Unbounded => {
4977                start_offset = 0;
4978                Bound::Unbounded
4979            }
4980        };
4981        let end = match range.end_bound() {
4982            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4983            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4984            Bound::Unbounded => Bound::Unbounded,
4985        };
4986        let bounds = (start, end);
4987
4988        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4989        cursor.seek(&DimensionPair {
4990            key: start_offset,
4991            value: None,
4992        });
4993
4994        if cursor
4995            .region()
4996            .is_some_and(|region| bounds.contains(&region.range.start.key))
4997        {
4998            cursor.prev_excerpt();
4999        } else {
5000            cursor.seek_to_start_of_current_excerpt();
5001        }
5002        let mut prev_region = cursor.region();
5003
5004        cursor.next_excerpt();
5005
5006        let mut visited_end = false;
5007        iter::from_fn(move || loop {
5008            if self.singleton {
5009                return None;
5010            }
5011
5012            let next_region = cursor.region();
5013            cursor.next_excerpt();
5014
5015            let next_region_start = if let Some(region) = &next_region {
5016                if !bounds.contains(&region.range.start.key) {
5017                    prev_region = next_region;
5018                    continue;
5019                }
5020                region.range.start.value.unwrap()
5021            } else {
5022                if !bounds.contains(&self.len()) {
5023                    return None;
5024                }
5025                self.max_point()
5026            };
5027            let next_region_end = if let Some(region) = cursor.region() {
5028                region.range.start.value.unwrap()
5029            } else {
5030                self.max_point()
5031            };
5032
5033            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5034                id: region.excerpt.id,
5035                buffer: region.excerpt.buffer.clone(),
5036                buffer_id: region.excerpt.buffer_id,
5037                range: region.excerpt.range.clone(),
5038                end_row: MultiBufferRow(next_region_start.row),
5039            });
5040
5041            let next = next_region.as_ref().map(|region| ExcerptInfo {
5042                id: region.excerpt.id,
5043                buffer: region.excerpt.buffer.clone(),
5044                buffer_id: region.excerpt.buffer_id,
5045                range: region.excerpt.range.clone(),
5046                end_row: if region.excerpt.has_trailing_newline {
5047                    MultiBufferRow(next_region_end.row - 1)
5048                } else {
5049                    MultiBufferRow(next_region_end.row)
5050                },
5051            });
5052
5053            if next.is_none() {
5054                if visited_end {
5055                    return None;
5056                } else {
5057                    visited_end = true;
5058                }
5059            }
5060
5061            let row = MultiBufferRow(next_region_start.row);
5062
5063            prev_region = next_region;
5064
5065            return Some(ExcerptBoundary { row, prev, next });
5066        })
5067    }
5068
5069    pub fn edit_count(&self) -> usize {
5070        self.edit_count
5071    }
5072
5073    pub fn non_text_state_update_count(&self) -> usize {
5074        self.non_text_state_update_count
5075    }
5076
5077    /// Returns the smallest enclosing bracket ranges containing the given range or
5078    /// None if no brackets contain range or the range is not contained in a single
5079    /// excerpt
5080    ///
5081    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5082    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5083        &self,
5084        range: Range<T>,
5085        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5086    ) -> Option<(Range<usize>, Range<usize>)> {
5087        let range = range.start.to_offset(self)..range.end.to_offset(self);
5088        let mut excerpt = self.excerpt_containing(range.clone())?;
5089        let buffer = excerpt.buffer();
5090        let excerpt_buffer_range = excerpt.buffer_range();
5091
5092        // Filter to ranges contained in the excerpt
5093        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5094            excerpt_buffer_range.contains(&open.start)
5095                && excerpt_buffer_range.contains(&close.end)
5096                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5097        };
5098
5099        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5100            excerpt.map_range_to_buffer(range),
5101            Some(&range_filter),
5102        )?;
5103
5104        Some((
5105            excerpt.map_range_from_buffer(open),
5106            excerpt.map_range_from_buffer(close),
5107        ))
5108    }
5109
5110    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5111    /// not contained in a single excerpt
5112    pub fn enclosing_bracket_ranges<T: ToOffset>(
5113        &self,
5114        range: Range<T>,
5115    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5116        let range = range.start.to_offset(self)..range.end.to_offset(self);
5117        let mut excerpt = self.excerpt_containing(range.clone())?;
5118
5119        Some(
5120            excerpt
5121                .buffer()
5122                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5123                .filter_map(move |pair| {
5124                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5125                        Some((
5126                            excerpt.map_range_from_buffer(pair.open_range),
5127                            excerpt.map_range_from_buffer(pair.close_range),
5128                        ))
5129                    } else {
5130                        None
5131                    }
5132                }),
5133        )
5134    }
5135
5136    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5137    /// not contained in a single excerpt
5138    pub fn text_object_ranges<T: ToOffset>(
5139        &self,
5140        range: Range<T>,
5141        options: TreeSitterOptions,
5142    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5143        let range = range.start.to_offset(self)..range.end.to_offset(self);
5144        self.excerpt_containing(range.clone())
5145            .map(|mut excerpt| {
5146                excerpt
5147                    .buffer()
5148                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5149                    .filter_map(move |(range, text_object)| {
5150                        if excerpt.contains_buffer_range(range.clone()) {
5151                            Some((excerpt.map_range_from_buffer(range), text_object))
5152                        } else {
5153                            None
5154                        }
5155                    })
5156            })
5157            .into_iter()
5158            .flatten()
5159    }
5160
5161    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5162    /// not contained in a single excerpt
5163    pub fn bracket_ranges<T: ToOffset>(
5164        &self,
5165        range: Range<T>,
5166    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5167        let range = range.start.to_offset(self)..range.end.to_offset(self);
5168        let mut excerpt = self.excerpt_containing(range.clone())?;
5169
5170        Some(
5171            excerpt
5172                .buffer()
5173                .bracket_ranges(excerpt.map_range_to_buffer(range))
5174                .filter_map(move |pair| {
5175                    let buffer_range = pair.open_range.start..pair.close_range.end;
5176                    if excerpt.contains_buffer_range(buffer_range) {
5177                        Some((
5178                            excerpt.map_range_from_buffer(pair.open_range),
5179                            excerpt.map_range_from_buffer(pair.close_range),
5180                        ))
5181                    } else {
5182                        None
5183                    }
5184                }),
5185        )
5186    }
5187
5188    pub fn redacted_ranges<'a, T: ToOffset>(
5189        &'a self,
5190        range: Range<T>,
5191        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5192    ) -> impl Iterator<Item = Range<usize>> + 'a {
5193        let range = range.start.to_offset(self)..range.end.to_offset(self);
5194        self.lift_buffer_metadata(range, move |buffer, range| {
5195            if redaction_enabled(buffer.file()) {
5196                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5197            } else {
5198                None
5199            }
5200        })
5201        .map(|(range, _, _)| range)
5202    }
5203
5204    pub fn runnable_ranges(
5205        &self,
5206        range: Range<Anchor>,
5207    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5208        let range = range.start.to_offset(self)..range.end.to_offset(self);
5209        self.lift_buffer_metadata(range, move |buffer, range| {
5210            Some(
5211                buffer
5212                    .runnable_ranges(range.clone())
5213                    .filter(move |runnable| {
5214                        runnable.run_range.start >= range.start
5215                            && runnable.run_range.end < range.end
5216                    })
5217                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5218            )
5219        })
5220        .map(|(run_range, runnable, _)| language::RunnableRange {
5221            run_range,
5222            ..runnable
5223        })
5224    }
5225
5226    pub fn line_indents(
5227        &self,
5228        start_row: MultiBufferRow,
5229        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5230    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5231        let max_point = self.max_point();
5232        let mut cursor = self.cursor::<Point>();
5233        cursor.seek(&Point::new(start_row.0, 0));
5234        iter::from_fn(move || {
5235            let mut region = cursor.region()?;
5236            while !buffer_filter(&region.excerpt.buffer) {
5237                cursor.next();
5238                region = cursor.region()?;
5239            }
5240            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5241            let buffer_start_row =
5242                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5243
5244            let buffer_end_row = if region.is_main_buffer
5245                && (region.has_trailing_newline || region.range.end == max_point)
5246            {
5247                region.buffer_range.end.row
5248            } else {
5249                region.buffer_range.end.row.saturating_sub(1)
5250            };
5251
5252            let line_indents = region
5253                .buffer
5254                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5255            cursor.next();
5256            return Some(line_indents.map(move |(buffer_row, indent)| {
5257                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5258                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5259            }));
5260        })
5261        .flatten()
5262    }
5263
5264    pub fn reversed_line_indents(
5265        &self,
5266        end_row: MultiBufferRow,
5267        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5268    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5269        let max_point = self.max_point();
5270        let mut cursor = self.cursor::<Point>();
5271        cursor.seek(&Point::new(end_row.0, 0));
5272        iter::from_fn(move || {
5273            let mut region = cursor.region()?;
5274            while !buffer_filter(&region.excerpt.buffer) {
5275                cursor.prev();
5276                region = cursor.region()?;
5277            }
5278
5279            let buffer_start_row = region.buffer_range.start.row;
5280            let buffer_end_row = if region.is_main_buffer
5281                && (region.has_trailing_newline || region.range.end == max_point)
5282            {
5283                region.buffer_range.end.row + 1
5284            } else {
5285                region.buffer_range.end.row
5286            };
5287
5288            let overshoot = end_row.0 - region.range.start.row;
5289            let buffer_end_row =
5290                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5291
5292            let line_indents = region
5293                .buffer
5294                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5295            cursor.prev();
5296            return Some(line_indents.map(move |(buffer_row, indent)| {
5297                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5298                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5299            }));
5300        })
5301        .flatten()
5302    }
5303
5304    pub async fn enclosing_indent(
5305        &self,
5306        mut target_row: MultiBufferRow,
5307    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5308        let max_row = MultiBufferRow(self.max_point().row);
5309        if target_row >= max_row {
5310            return None;
5311        }
5312
5313        let mut target_indent = self.line_indent_for_row(target_row);
5314
5315        // If the current row is at the start of an indented block, we want to return this
5316        // block as the enclosing indent.
5317        if !target_indent.is_line_empty() && target_row < max_row {
5318            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5319            if !next_line_indent.is_line_empty()
5320                && target_indent.raw_len() < next_line_indent.raw_len()
5321            {
5322                target_indent = next_line_indent;
5323                target_row.0 += 1;
5324            }
5325        }
5326
5327        const SEARCH_ROW_LIMIT: u32 = 25000;
5328        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5329        const YIELD_INTERVAL: u32 = 100;
5330
5331        let mut accessed_row_counter = 0;
5332
5333        // If there is a blank line at the current row, search for the next non indented lines
5334        if target_indent.is_line_empty() {
5335            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5336            let end =
5337                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5338
5339            let mut non_empty_line_above = None;
5340            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5341                if row < start {
5342                    break;
5343                }
5344                accessed_row_counter += 1;
5345                if accessed_row_counter == YIELD_INTERVAL {
5346                    accessed_row_counter = 0;
5347                    yield_now().await;
5348                }
5349                if !indent.is_line_empty() {
5350                    non_empty_line_above = Some((row, indent));
5351                    break;
5352                }
5353            }
5354
5355            let mut non_empty_line_below = None;
5356            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5357                if row > end {
5358                    break;
5359                }
5360                accessed_row_counter += 1;
5361                if accessed_row_counter == YIELD_INTERVAL {
5362                    accessed_row_counter = 0;
5363                    yield_now().await;
5364                }
5365                if !indent.is_line_empty() {
5366                    non_empty_line_below = Some((row, indent));
5367                    break;
5368                }
5369            }
5370
5371            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5372                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5373                    if above_indent.raw_len() >= below_indent.raw_len() {
5374                        (above_row, above_indent)
5375                    } else {
5376                        (below_row, below_indent)
5377                    }
5378                }
5379                (Some(above), None) => above,
5380                (None, Some(below)) => below,
5381                _ => return None,
5382            };
5383
5384            target_indent = indent;
5385            target_row = row;
5386        }
5387
5388        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5389        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5390
5391        let mut start_indent = None;
5392        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5393            if row < start {
5394                break;
5395            }
5396            accessed_row_counter += 1;
5397            if accessed_row_counter == YIELD_INTERVAL {
5398                accessed_row_counter = 0;
5399                yield_now().await;
5400            }
5401            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5402                start_indent = Some((row, indent));
5403                break;
5404            }
5405        }
5406        let (start_row, start_indent_size) = start_indent?;
5407
5408        let mut end_indent = (end, None);
5409        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5410            if row > end {
5411                break;
5412            }
5413            accessed_row_counter += 1;
5414            if accessed_row_counter == YIELD_INTERVAL {
5415                accessed_row_counter = 0;
5416                yield_now().await;
5417            }
5418            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5419                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5420                break;
5421            }
5422        }
5423        let (end_row, end_indent_size) = end_indent;
5424
5425        let indent = if let Some(end_indent_size) = end_indent_size {
5426            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5427                start_indent_size
5428            } else {
5429                end_indent_size
5430            }
5431        } else {
5432            start_indent_size
5433        };
5434
5435        Some((start_row..end_row, indent))
5436    }
5437
5438    pub fn indent_guides_in_range<T: ToPoint>(
5439        &self,
5440        range: Range<T>,
5441        ignore_disabled_for_language: bool,
5442        cx: &App,
5443    ) -> impl Iterator<Item = IndentGuide> {
5444        let range = range.start.to_point(self)..range.end.to_point(self);
5445        let start_row = MultiBufferRow(range.start.row);
5446        let end_row = MultiBufferRow(range.end.row);
5447
5448        let mut row_indents = self.line_indents(start_row, |buffer| {
5449            let settings =
5450                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5451            settings.indent_guides.enabled || ignore_disabled_for_language
5452        });
5453
5454        let mut result = Vec::new();
5455        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5456
5457        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5458            if first_row > end_row {
5459                break;
5460            }
5461            let current_depth = indent_stack.len() as u32;
5462
5463            let settings =
5464                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5465            let tab_size = settings.tab_size.get() as u32;
5466
5467            // When encountering empty, continue until found useful line indent
5468            // then add to the indent stack with the depth found
5469            let mut found_indent = false;
5470            let mut last_row = first_row;
5471            if line_indent.is_line_empty() {
5472                while !found_indent {
5473                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5474                        break;
5475                    };
5476                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5477                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5478                        break;
5479                    }
5480
5481                    if new_line_indent.is_line_empty() {
5482                        continue;
5483                    }
5484                    last_row = target_row.min(end_row);
5485                    line_indent = new_line_indent;
5486                    found_indent = true;
5487                    break;
5488                }
5489            } else {
5490                found_indent = true
5491            }
5492
5493            let depth = if found_indent {
5494                line_indent.len(tab_size) / tab_size
5495                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5496            } else {
5497                current_depth
5498            };
5499
5500            match depth.cmp(&current_depth) {
5501                cmp::Ordering::Less => {
5502                    for _ in 0..(current_depth - depth) {
5503                        let mut indent = indent_stack.pop().unwrap();
5504                        if last_row != first_row {
5505                            // In this case, we landed on an empty row, had to seek forward,
5506                            // and discovered that the indent we where on is ending.
5507                            // This means that the last display row must
5508                            // be on line that ends this indent range, so we
5509                            // should display the range up to the first non-empty line
5510                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5511                        }
5512
5513                        result.push(indent)
5514                    }
5515                }
5516                cmp::Ordering::Greater => {
5517                    for next_depth in current_depth..depth {
5518                        indent_stack.push(IndentGuide {
5519                            buffer_id: buffer.remote_id(),
5520                            start_row: first_row,
5521                            end_row: last_row,
5522                            depth: next_depth,
5523                            tab_size,
5524                            settings: settings.indent_guides,
5525                        });
5526                    }
5527                }
5528                _ => {}
5529            }
5530
5531            for indent in indent_stack.iter_mut() {
5532                indent.end_row = last_row;
5533            }
5534        }
5535
5536        result.extend(indent_stack);
5537        result.into_iter()
5538    }
5539
5540    pub fn trailing_excerpt_update_count(&self) -> usize {
5541        self.trailing_excerpt_update_count
5542    }
5543
5544    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5545        self.point_to_buffer_offset(point)
5546            .and_then(|(buffer, _)| buffer.file())
5547    }
5548
5549    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5550        self.point_to_buffer_offset(point)
5551            .and_then(|(buffer, offset)| buffer.language_at(offset))
5552    }
5553
5554    pub fn settings_at<'a, T: ToOffset>(
5555        &'a self,
5556        point: T,
5557        cx: &'a App,
5558    ) -> Cow<'a, LanguageSettings> {
5559        let mut language = None;
5560        let mut file = None;
5561        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5562            language = buffer.language_at(offset);
5563            file = buffer.file();
5564        }
5565        language_settings(language.map(|l| l.name()), file, cx)
5566    }
5567
5568    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5569        self.point_to_buffer_offset(point)
5570            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5571    }
5572
5573    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5574        self.point_to_buffer_offset(point)
5575            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5576            .unwrap_or_default()
5577    }
5578
5579    pub fn language_indent_size_at<T: ToOffset>(
5580        &self,
5581        position: T,
5582        cx: &App,
5583    ) -> Option<IndentSize> {
5584        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5585        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5586    }
5587
5588    pub fn is_dirty(&self) -> bool {
5589        self.is_dirty
5590    }
5591
5592    pub fn has_deleted_file(&self) -> bool {
5593        self.has_deleted_file
5594    }
5595
5596    pub fn has_conflict(&self) -> bool {
5597        self.has_conflict
5598    }
5599
5600    pub fn has_diagnostics(&self) -> bool {
5601        self.excerpts
5602            .iter()
5603            .any(|excerpt| excerpt.buffer.has_diagnostics())
5604    }
5605
5606    pub fn diagnostic_group(
5607        &self,
5608        buffer_id: BufferId,
5609        group_id: usize,
5610    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5611        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5612            if buffer.remote_id() != buffer_id {
5613                return None;
5614            };
5615            Some(
5616                buffer
5617                    .diagnostic_group(group_id)
5618                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5619            )
5620        })
5621        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5622    }
5623
5624    pub fn diagnostics_in_range<'a, T>(
5625        &'a self,
5626        range: Range<T>,
5627    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5628    where
5629        T: 'a
5630            + text::ToOffset
5631            + text::FromAnchor
5632            + TextDimension
5633            + Ord
5634            + Sub<T, Output = T>
5635            + fmt::Debug,
5636    {
5637        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5638            Some(
5639                buffer
5640                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5641                    .map(|entry| (entry.range, entry.diagnostic)),
5642            )
5643        })
5644        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5645    }
5646
5647    pub fn syntax_ancestor<T: ToOffset>(
5648        &self,
5649        range: Range<T>,
5650    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5651        let range = range.start.to_offset(self)..range.end.to_offset(self);
5652        let mut excerpt = self.excerpt_containing(range.clone())?;
5653        let node = excerpt
5654            .buffer()
5655            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5656        let node_range = node.byte_range();
5657        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5658            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5659        } else {
5660            MultiOrSingleBufferOffsetRange::Single(node_range)
5661        };
5662        Some((node, range))
5663    }
5664
5665    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5666        let (excerpt_id, _, buffer) = self.as_singleton()?;
5667        let outline = buffer.outline(theme)?;
5668        Some(Outline::new(
5669            outline
5670                .items
5671                .into_iter()
5672                .flat_map(|item| {
5673                    Some(OutlineItem {
5674                        depth: item.depth,
5675                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5676                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5677                        text: item.text,
5678                        highlight_ranges: item.highlight_ranges,
5679                        name_ranges: item.name_ranges,
5680                        body_range: item.body_range.and_then(|body_range| {
5681                            Some(
5682                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5683                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5684                            )
5685                        }),
5686                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5687                            Some(
5688                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5689                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5690                            )
5691                        }),
5692                    })
5693                })
5694                .collect(),
5695        ))
5696    }
5697
5698    pub fn symbols_containing<T: ToOffset>(
5699        &self,
5700        offset: T,
5701        theme: Option<&SyntaxTheme>,
5702    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5703        let anchor = self.anchor_before(offset);
5704        let excerpt_id = anchor.excerpt_id;
5705        let excerpt = self.excerpt(excerpt_id)?;
5706        Some((
5707            excerpt.buffer_id,
5708            excerpt
5709                .buffer
5710                .symbols_containing(anchor.text_anchor, theme)
5711                .into_iter()
5712                .flatten()
5713                .flat_map(|item| {
5714                    Some(OutlineItem {
5715                        depth: item.depth,
5716                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5717                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5718                        text: item.text,
5719                        highlight_ranges: item.highlight_ranges,
5720                        name_ranges: item.name_ranges,
5721                        body_range: item.body_range.and_then(|body_range| {
5722                            Some(
5723                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5724                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5725                            )
5726                        }),
5727                        annotation_range: item.annotation_range.and_then(|body_range| {
5728                            Some(
5729                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5730                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5731                            )
5732                        }),
5733                    })
5734                })
5735                .collect(),
5736        ))
5737    }
5738
5739    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5740        if id == ExcerptId::min() {
5741            Locator::min_ref()
5742        } else if id == ExcerptId::max() {
5743            Locator::max_ref()
5744        } else {
5745            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5746            cursor.seek(&id, Bias::Left, &());
5747            if let Some(entry) = cursor.item() {
5748                if entry.id == id {
5749                    return &entry.locator;
5750                }
5751            }
5752            panic!("invalid excerpt id {:?}", id)
5753        }
5754    }
5755
5756    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5757    fn excerpt_locators_for_ids(
5758        &self,
5759        ids: impl IntoIterator<Item = ExcerptId>,
5760    ) -> SmallVec<[Locator; 1]> {
5761        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5762        sorted_ids.sort_unstable();
5763        let mut locators = SmallVec::new();
5764
5765        while sorted_ids.last() == Some(&ExcerptId::max()) {
5766            sorted_ids.pop();
5767            if let Some(mapping) = self.excerpt_ids.last() {
5768                locators.push(mapping.locator.clone());
5769            }
5770        }
5771
5772        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5773        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5774            sorted_ids.next();
5775            if let Some(mapping) = self.excerpt_ids.first() {
5776                locators.push(mapping.locator.clone());
5777            }
5778        }
5779
5780        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5781        for id in sorted_ids {
5782            if cursor.seek_forward(&id, Bias::Left, &()) {
5783                locators.push(cursor.item().unwrap().locator.clone());
5784            } else {
5785                panic!("invalid excerpt id {:?}", id);
5786            }
5787        }
5788
5789        locators.sort_unstable();
5790        locators
5791    }
5792
5793    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5794        Some(self.excerpt(excerpt_id)?.buffer_id)
5795    }
5796
5797    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5798        Some(&self.excerpt(excerpt_id)?.buffer)
5799    }
5800
5801    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5802        let mut cursor = self
5803            .excerpts
5804            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5805        let locator = self.excerpt_locator_for_id(excerpt_id);
5806        if cursor.seek(&Some(locator), Bias::Left, &()) {
5807            let start = cursor.start().1.clone();
5808            let end = cursor.end(&()).1;
5809            let mut diff_transforms = self
5810                .diff_transforms
5811                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5812            diff_transforms.seek(&start, Bias::Left, &());
5813            let overshoot = start.0 - diff_transforms.start().0 .0;
5814            let start = diff_transforms.start().1 .0 + overshoot;
5815            diff_transforms.seek(&end, Bias::Right, &());
5816            let overshoot = end.0 - diff_transforms.start().0 .0;
5817            let end = diff_transforms.start().1 .0 + overshoot;
5818            Some(start..end)
5819        } else {
5820            None
5821        }
5822    }
5823
5824    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5825        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5826        let locator = self.excerpt_locator_for_id(excerpt_id);
5827        if cursor.seek(&Some(locator), Bias::Left, &()) {
5828            if let Some(excerpt) = cursor.item() {
5829                return Some(excerpt.range.context.clone());
5830            }
5831        }
5832        None
5833    }
5834
5835    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5836        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5837        let locator = self.excerpt_locator_for_id(excerpt_id);
5838        cursor.seek(&Some(locator), Bias::Left, &());
5839        if let Some(excerpt) = cursor.item() {
5840            if excerpt.id == excerpt_id {
5841                return Some(excerpt);
5842            }
5843        }
5844        None
5845    }
5846
5847    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5848    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5849        let range = range.start.to_offset(self)..range.end.to_offset(self);
5850        let mut cursor = self.cursor::<usize>();
5851        cursor.seek(&range.start);
5852
5853        let start_excerpt = cursor.excerpt()?;
5854        if range.end != range.start {
5855            cursor.seek_forward(&range.end);
5856            if cursor.excerpt()?.id != start_excerpt.id {
5857                return None;
5858            }
5859        }
5860
5861        cursor.seek_to_start_of_current_excerpt();
5862        let region = cursor.region()?;
5863        let offset = region.range.start;
5864        let buffer_offset = region.buffer_range.start;
5865        let excerpt_offset = cursor.excerpts.start().clone();
5866        Some(MultiBufferExcerpt {
5867            diff_transforms: cursor.diff_transforms,
5868            excerpt: start_excerpt,
5869            offset,
5870            buffer_offset,
5871            excerpt_offset,
5872        })
5873    }
5874
5875    pub fn selections_in_range<'a>(
5876        &'a self,
5877        range: &'a Range<Anchor>,
5878        include_local: bool,
5879    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5880        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5881        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5882        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5883        cursor.seek(start_locator, Bias::Left, &());
5884        cursor
5885            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5886            .flat_map(move |excerpt| {
5887                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5888                if excerpt.id == range.start.excerpt_id {
5889                    query_range.start = range.start.text_anchor;
5890                }
5891                if excerpt.id == range.end.excerpt_id {
5892                    query_range.end = range.end.text_anchor;
5893                }
5894
5895                excerpt
5896                    .buffer
5897                    .selections_in_range(query_range, include_local)
5898                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5899                        selections.map(move |selection| {
5900                            let mut start = Anchor {
5901                                buffer_id: Some(excerpt.buffer_id),
5902                                excerpt_id: excerpt.id,
5903                                text_anchor: selection.start,
5904                                diff_base_anchor: None,
5905                            };
5906                            let mut end = Anchor {
5907                                buffer_id: Some(excerpt.buffer_id),
5908                                excerpt_id: excerpt.id,
5909                                text_anchor: selection.end,
5910                                diff_base_anchor: None,
5911                            };
5912                            if range.start.cmp(&start, self).is_gt() {
5913                                start = range.start;
5914                            }
5915                            if range.end.cmp(&end, self).is_lt() {
5916                                end = range.end;
5917                            }
5918
5919                            (
5920                                replica_id,
5921                                line_mode,
5922                                cursor_shape,
5923                                Selection {
5924                                    id: selection.id,
5925                                    start,
5926                                    end,
5927                                    reversed: selection.reversed,
5928                                    goal: selection.goal,
5929                                },
5930                            )
5931                        })
5932                    })
5933            })
5934    }
5935
5936    pub fn show_headers(&self) -> bool {
5937        self.show_headers
5938    }
5939
5940    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5941        self.diffs.get(&buffer_id)
5942    }
5943}
5944
5945#[cfg(any(test, feature = "test-support"))]
5946impl MultiBufferSnapshot {
5947    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5948        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5949        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5950        start..end
5951    }
5952
5953    #[cfg(any(test, feature = "test-support"))]
5954    fn check_invariants(&self) {
5955        let excerpts = self.excerpts.items(&());
5956        let excerpt_ids = self.excerpt_ids.items(&());
5957
5958        for (ix, excerpt) in excerpts.iter().enumerate() {
5959            if ix == 0 {
5960                if excerpt.locator <= Locator::min() {
5961                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5962                }
5963            } else if excerpt.locator <= excerpts[ix - 1].locator {
5964                panic!("excerpts are out-of-order: {:?}", excerpts);
5965            }
5966        }
5967
5968        for (ix, entry) in excerpt_ids.iter().enumerate() {
5969            if ix == 0 {
5970                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
5971                    panic!("invalid first excerpt id {:?}", entry.id);
5972                }
5973            } else if entry.id <= excerpt_ids[ix - 1].id {
5974                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5975            }
5976        }
5977
5978        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5979            panic!(
5980                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5981                self.excerpts.summary().text.len,
5982                self.diff_transforms.summary().input,
5983                self.diff_transforms.items(&()),
5984            );
5985        }
5986
5987        let mut prev_transform: Option<&DiffTransform> = None;
5988        for item in self.diff_transforms.iter() {
5989            if let DiffTransform::BufferContent {
5990                summary,
5991                inserted_hunk_info,
5992            } = item
5993            {
5994                if let Some(DiffTransform::BufferContent {
5995                    inserted_hunk_info: prev_inserted_hunk_info,
5996                    ..
5997                }) = prev_transform
5998                {
5999                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6000                        panic!(
6001                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6002                            self.diff_transforms.items(&()));
6003                    }
6004                }
6005                if summary.len == 0 && !self.is_empty() {
6006                    panic!("empty buffer content transform");
6007                }
6008            }
6009            prev_transform = Some(item);
6010        }
6011    }
6012}
6013
6014impl<'a, D> MultiBufferCursor<'a, D>
6015where
6016    D: TextDimension + Ord + Sub<D, Output = D>,
6017{
6018    fn seek(&mut self, position: &D) {
6019        self.cached_region.take();
6020        self.diff_transforms
6021            .seek(&OutputDimension(*position), Bias::Right, &());
6022        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6023            self.diff_transforms.prev(&());
6024        }
6025
6026        let mut excerpt_position = self.diff_transforms.start().1 .0;
6027        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6028            let overshoot = *position - self.diff_transforms.start().0 .0;
6029            excerpt_position.add_assign(&overshoot);
6030        }
6031
6032        self.excerpts
6033            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6034        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6035            self.excerpts.prev(&());
6036        }
6037    }
6038
6039    fn seek_forward(&mut self, position: &D) {
6040        self.cached_region.take();
6041        self.diff_transforms
6042            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6043        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6044            self.diff_transforms.prev(&());
6045        }
6046
6047        let overshoot = *position - self.diff_transforms.start().0 .0;
6048        let mut excerpt_position = self.diff_transforms.start().1 .0;
6049        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6050            excerpt_position.add_assign(&overshoot);
6051        }
6052
6053        self.excerpts
6054            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6055        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6056            self.excerpts.prev(&());
6057        }
6058    }
6059
6060    fn next_excerpt(&mut self) {
6061        self.excerpts.next(&());
6062        self.seek_to_start_of_current_excerpt();
6063    }
6064
6065    fn prev_excerpt(&mut self) {
6066        self.excerpts.prev(&());
6067        self.seek_to_start_of_current_excerpt();
6068    }
6069
6070    fn seek_to_start_of_current_excerpt(&mut self) {
6071        self.cached_region.take();
6072        self.diff_transforms
6073            .seek(self.excerpts.start(), Bias::Left, &());
6074        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6075            && self.diff_transforms.start().1 < *self.excerpts.start()
6076            && self.diff_transforms.next_item().is_some()
6077        {
6078            self.diff_transforms.next(&());
6079        }
6080    }
6081
6082    fn next(&mut self) {
6083        self.cached_region.take();
6084        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6085            cmp::Ordering::Less => self.diff_transforms.next(&()),
6086            cmp::Ordering::Greater => self.excerpts.next(&()),
6087            cmp::Ordering::Equal => {
6088                self.diff_transforms.next(&());
6089                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6090                    || self.diff_transforms.item().is_none()
6091                {
6092                    self.excerpts.next(&());
6093                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6094                    self.diff_transforms.item()
6095                {
6096                    if self
6097                        .excerpts
6098                        .item()
6099                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6100                    {
6101                        self.excerpts.next(&());
6102                    }
6103                }
6104            }
6105        }
6106    }
6107
6108    fn prev(&mut self) {
6109        self.cached_region.take();
6110        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6111            cmp::Ordering::Less => self.excerpts.prev(&()),
6112            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6113            cmp::Ordering::Equal => {
6114                self.diff_transforms.prev(&());
6115                if self.diff_transforms.start().1 < *self.excerpts.start()
6116                    || self.diff_transforms.item().is_none()
6117                {
6118                    self.excerpts.prev(&());
6119                }
6120            }
6121        }
6122    }
6123
6124    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6125        if self.cached_region.is_none() {
6126            self.cached_region = self.build_region();
6127        }
6128        self.cached_region.clone()
6129    }
6130
6131    fn is_at_end_of_excerpt(&mut self) -> bool {
6132        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6133            return false;
6134        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6135            || self.diff_transforms.item().is_none()
6136        {
6137            return true;
6138        }
6139
6140        let next_transform = self.diff_transforms.next_item();
6141        next_transform.map_or(true, |next_transform| match next_transform {
6142            DiffTransform::BufferContent { .. } => true,
6143            DiffTransform::DeletedHunk { hunk_info, .. } => self
6144                .excerpts
6145                .item()
6146                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6147        })
6148    }
6149
6150    fn main_buffer_position(&self) -> Option<D> {
6151        let excerpt = self.excerpts.item()?;
6152        let buffer = &excerpt.buffer;
6153        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6154        let mut buffer_start = buffer_context_start;
6155        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6156        buffer_start.add_assign(&overshoot);
6157        Some(buffer_start)
6158    }
6159
6160    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6161        let excerpt = self.excerpts.item()?;
6162        match self.diff_transforms.item()? {
6163            DiffTransform::DeletedHunk {
6164                buffer_id,
6165                base_text_byte_range,
6166                has_trailing_newline,
6167                hunk_info,
6168                ..
6169            } => {
6170                let diff = self.diffs.get(&buffer_id)?;
6171                let buffer = diff.base_text();
6172                let mut rope_cursor = buffer.as_rope().cursor(0);
6173                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6174                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6175                let mut buffer_end = buffer_start;
6176                buffer_end.add_assign(&buffer_range_len);
6177                let start = self.diff_transforms.start().0 .0;
6178                let end = self.diff_transforms.end(&()).0 .0;
6179                return Some(MultiBufferRegion {
6180                    buffer,
6181                    excerpt,
6182                    has_trailing_newline: *has_trailing_newline,
6183                    is_main_buffer: false,
6184                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6185                        hunk_info.hunk_secondary_status,
6186                    )),
6187                    buffer_range: buffer_start..buffer_end,
6188                    range: start..end,
6189                });
6190            }
6191            DiffTransform::BufferContent {
6192                inserted_hunk_info, ..
6193            } => {
6194                let buffer = &excerpt.buffer;
6195                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6196
6197                let mut start = self.diff_transforms.start().0 .0;
6198                let mut buffer_start = buffer_context_start;
6199                if self.diff_transforms.start().1 < *self.excerpts.start() {
6200                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6201                    start.add_assign(&overshoot);
6202                } else {
6203                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6204                    buffer_start.add_assign(&overshoot);
6205                }
6206
6207                let mut end;
6208                let mut buffer_end;
6209                let has_trailing_newline;
6210                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6211                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6212                    end = self.diff_transforms.end(&()).0 .0;
6213                    buffer_end = buffer_context_start;
6214                    buffer_end.add_assign(&overshoot);
6215                    has_trailing_newline = false;
6216                } else {
6217                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6218                    end = self.diff_transforms.start().0 .0;
6219                    end.add_assign(&overshoot);
6220                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6221                    has_trailing_newline = excerpt.has_trailing_newline;
6222                };
6223
6224                Some(MultiBufferRegion {
6225                    buffer,
6226                    excerpt,
6227                    has_trailing_newline,
6228                    is_main_buffer: true,
6229                    diff_hunk_status: inserted_hunk_info
6230                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6231                    buffer_range: buffer_start..buffer_end,
6232                    range: start..end,
6233                })
6234            }
6235        }
6236    }
6237
6238    fn excerpt(&self) -> Option<&'a Excerpt> {
6239        self.excerpts.item()
6240    }
6241}
6242
6243impl History {
6244    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6245        self.transaction_depth += 1;
6246        if self.transaction_depth == 1 {
6247            let id = self.next_transaction_id.tick();
6248            self.undo_stack.push(Transaction {
6249                id,
6250                buffer_transactions: Default::default(),
6251                first_edit_at: now,
6252                last_edit_at: now,
6253                suppress_grouping: false,
6254            });
6255            Some(id)
6256        } else {
6257            None
6258        }
6259    }
6260
6261    fn end_transaction(
6262        &mut self,
6263        now: Instant,
6264        buffer_transactions: HashMap<BufferId, TransactionId>,
6265    ) -> bool {
6266        assert_ne!(self.transaction_depth, 0);
6267        self.transaction_depth -= 1;
6268        if self.transaction_depth == 0 {
6269            if buffer_transactions.is_empty() {
6270                self.undo_stack.pop();
6271                false
6272            } else {
6273                self.redo_stack.clear();
6274                let transaction = self.undo_stack.last_mut().unwrap();
6275                transaction.last_edit_at = now;
6276                for (buffer_id, transaction_id) in buffer_transactions {
6277                    transaction
6278                        .buffer_transactions
6279                        .entry(buffer_id)
6280                        .or_insert(transaction_id);
6281                }
6282                true
6283            }
6284        } else {
6285            false
6286        }
6287    }
6288
6289    fn push_transaction<'a, T>(
6290        &mut self,
6291        buffer_transactions: T,
6292        now: Instant,
6293        cx: &Context<MultiBuffer>,
6294    ) where
6295        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6296    {
6297        assert_eq!(self.transaction_depth, 0);
6298        let transaction = Transaction {
6299            id: self.next_transaction_id.tick(),
6300            buffer_transactions: buffer_transactions
6301                .into_iter()
6302                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6303                .collect(),
6304            first_edit_at: now,
6305            last_edit_at: now,
6306            suppress_grouping: false,
6307        };
6308        if !transaction.buffer_transactions.is_empty() {
6309            self.undo_stack.push(transaction);
6310            self.redo_stack.clear();
6311        }
6312    }
6313
6314    fn finalize_last_transaction(&mut self) {
6315        if let Some(transaction) = self.undo_stack.last_mut() {
6316            transaction.suppress_grouping = true;
6317        }
6318    }
6319
6320    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6321        if let Some(ix) = self
6322            .undo_stack
6323            .iter()
6324            .rposition(|transaction| transaction.id == transaction_id)
6325        {
6326            Some(self.undo_stack.remove(ix))
6327        } else if let Some(ix) = self
6328            .redo_stack
6329            .iter()
6330            .rposition(|transaction| transaction.id == transaction_id)
6331        {
6332            Some(self.redo_stack.remove(ix))
6333        } else {
6334            None
6335        }
6336    }
6337
6338    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6339        self.undo_stack
6340            .iter()
6341            .find(|transaction| transaction.id == transaction_id)
6342            .or_else(|| {
6343                self.redo_stack
6344                    .iter()
6345                    .find(|transaction| transaction.id == transaction_id)
6346            })
6347    }
6348
6349    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6350        self.undo_stack
6351            .iter_mut()
6352            .find(|transaction| transaction.id == transaction_id)
6353            .or_else(|| {
6354                self.redo_stack
6355                    .iter_mut()
6356                    .find(|transaction| transaction.id == transaction_id)
6357            })
6358    }
6359
6360    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6361        assert_eq!(self.transaction_depth, 0);
6362        if let Some(transaction) = self.undo_stack.pop() {
6363            self.redo_stack.push(transaction);
6364            self.redo_stack.last_mut()
6365        } else {
6366            None
6367        }
6368    }
6369
6370    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6371        assert_eq!(self.transaction_depth, 0);
6372        if let Some(transaction) = self.redo_stack.pop() {
6373            self.undo_stack.push(transaction);
6374            self.undo_stack.last_mut()
6375        } else {
6376            None
6377        }
6378    }
6379
6380    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6381        let ix = self
6382            .undo_stack
6383            .iter()
6384            .rposition(|transaction| transaction.id == transaction_id)?;
6385        let transaction = self.undo_stack.remove(ix);
6386        self.redo_stack.push(transaction);
6387        self.redo_stack.last()
6388    }
6389
6390    fn group(&mut self) -> Option<TransactionId> {
6391        let mut count = 0;
6392        let mut transactions = self.undo_stack.iter();
6393        if let Some(mut transaction) = transactions.next_back() {
6394            while let Some(prev_transaction) = transactions.next_back() {
6395                if !prev_transaction.suppress_grouping
6396                    && transaction.first_edit_at - prev_transaction.last_edit_at
6397                        <= self.group_interval
6398                {
6399                    transaction = prev_transaction;
6400                    count += 1;
6401                } else {
6402                    break;
6403                }
6404            }
6405        }
6406        self.group_trailing(count)
6407    }
6408
6409    fn group_until(&mut self, transaction_id: TransactionId) {
6410        let mut count = 0;
6411        for transaction in self.undo_stack.iter().rev() {
6412            if transaction.id == transaction_id {
6413                self.group_trailing(count);
6414                break;
6415            } else if transaction.suppress_grouping {
6416                break;
6417            } else {
6418                count += 1;
6419            }
6420        }
6421    }
6422
6423    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6424        let new_len = self.undo_stack.len() - n;
6425        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6426        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6427            if let Some(transaction) = transactions_to_merge.last() {
6428                last_transaction.last_edit_at = transaction.last_edit_at;
6429            }
6430            for to_merge in transactions_to_merge {
6431                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6432                    last_transaction
6433                        .buffer_transactions
6434                        .entry(*buffer_id)
6435                        .or_insert(*transaction_id);
6436                }
6437            }
6438        }
6439
6440        self.undo_stack.truncate(new_len);
6441        self.undo_stack.last().map(|t| t.id)
6442    }
6443}
6444
6445impl Excerpt {
6446    fn new(
6447        id: ExcerptId,
6448        locator: Locator,
6449        buffer_id: BufferId,
6450        buffer: BufferSnapshot,
6451        range: ExcerptRange<text::Anchor>,
6452        has_trailing_newline: bool,
6453    ) -> Self {
6454        Excerpt {
6455            id,
6456            locator,
6457            max_buffer_row: range.context.end.to_point(&buffer).row,
6458            text_summary: buffer
6459                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6460            buffer_id,
6461            buffer,
6462            range,
6463            has_trailing_newline,
6464        }
6465    }
6466
6467    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6468        let content_start = self.range.context.start.to_offset(&self.buffer);
6469        let chunks_start = content_start + range.start;
6470        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6471
6472        let footer_height = if self.has_trailing_newline
6473            && range.start <= self.text_summary.len
6474            && range.end > self.text_summary.len
6475        {
6476            1
6477        } else {
6478            0
6479        };
6480
6481        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6482
6483        ExcerptChunks {
6484            excerpt_id: self.id,
6485            content_chunks,
6486            footer_height,
6487        }
6488    }
6489
6490    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6491        let content_start = self.range.context.start.to_offset(&self.buffer);
6492        let chunks_start = content_start + range.start;
6493        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6494        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6495        excerpt_chunks.footer_height = if self.has_trailing_newline
6496            && range.start <= self.text_summary.len
6497            && range.end > self.text_summary.len
6498        {
6499            1
6500        } else {
6501            0
6502        };
6503    }
6504
6505    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6506        if text_anchor
6507            .cmp(&self.range.context.start, &self.buffer)
6508            .is_lt()
6509        {
6510            self.range.context.start
6511        } else if text_anchor
6512            .cmp(&self.range.context.end, &self.buffer)
6513            .is_gt()
6514        {
6515            self.range.context.end
6516        } else {
6517            text_anchor
6518        }
6519    }
6520
6521    fn contains(&self, anchor: &Anchor) -> bool {
6522        Some(self.buffer_id) == anchor.buffer_id
6523            && self
6524                .range
6525                .context
6526                .start
6527                .cmp(&anchor.text_anchor, &self.buffer)
6528                .is_le()
6529            && self
6530                .range
6531                .context
6532                .end
6533                .cmp(&anchor.text_anchor, &self.buffer)
6534                .is_ge()
6535    }
6536
6537    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6538    fn buffer_start_offset(&self) -> usize {
6539        self.range.context.start.to_offset(&self.buffer)
6540    }
6541
6542    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6543    fn buffer_end_offset(&self) -> usize {
6544        self.buffer_start_offset() + self.text_summary.len
6545    }
6546}
6547
6548impl<'a> MultiBufferExcerpt<'a> {
6549    pub fn id(&self) -> ExcerptId {
6550        self.excerpt.id
6551    }
6552
6553    pub fn buffer_id(&self) -> BufferId {
6554        self.excerpt.buffer_id
6555    }
6556
6557    pub fn start_anchor(&self) -> Anchor {
6558        Anchor {
6559            buffer_id: Some(self.excerpt.buffer_id),
6560            excerpt_id: self.excerpt.id,
6561            text_anchor: self.excerpt.range.context.start,
6562            diff_base_anchor: None,
6563        }
6564    }
6565
6566    pub fn end_anchor(&self) -> Anchor {
6567        Anchor {
6568            buffer_id: Some(self.excerpt.buffer_id),
6569            excerpt_id: self.excerpt.id,
6570            text_anchor: self.excerpt.range.context.end,
6571            diff_base_anchor: None,
6572        }
6573    }
6574
6575    pub fn buffer(&self) -> &'a BufferSnapshot {
6576        &self.excerpt.buffer
6577    }
6578
6579    pub fn buffer_range(&self) -> Range<usize> {
6580        self.buffer_offset
6581            ..self
6582                .excerpt
6583                .range
6584                .context
6585                .end
6586                .to_offset(&self.excerpt.buffer.text)
6587    }
6588
6589    pub fn start_offset(&self) -> usize {
6590        self.offset
6591    }
6592
6593    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6594    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6595        self.map_range_to_buffer(offset..offset).start
6596    }
6597
6598    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6599    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6600        self.diff_transforms
6601            .seek(&OutputDimension(range.start), Bias::Right, &());
6602        let start = self.map_offset_to_buffer_internal(range.start);
6603        let end = if range.end > range.start {
6604            self.diff_transforms
6605                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6606            self.map_offset_to_buffer_internal(range.end)
6607        } else {
6608            start
6609        };
6610        start..end
6611    }
6612
6613    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6614        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6615        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6616            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6617        };
6618        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6619        self.buffer_offset + offset_in_excerpt
6620    }
6621
6622    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6623    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6624        self.map_range_from_buffer(buffer_offset..buffer_offset)
6625            .start
6626    }
6627
6628    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6629    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6630        if buffer_range.start < self.buffer_offset {
6631            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6632            return buffer_range;
6633        }
6634        let overshoot = buffer_range.start - self.buffer_offset;
6635        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6636        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6637        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6638            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6639            return buffer_range;
6640        }
6641        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6642        let start = self.diff_transforms.start().0 .0 + overshoot;
6643
6644        let end = if buffer_range.end > buffer_range.start {
6645            let overshoot = buffer_range.end - self.buffer_offset;
6646            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6647            self.diff_transforms
6648                .seek_forward(&excerpt_offset, Bias::Right, &());
6649            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6650            self.diff_transforms.start().0 .0 + overshoot
6651        } else {
6652            start
6653        };
6654
6655        start..end
6656    }
6657
6658    /// Returns true if the entirety of the given range is in the buffer's excerpt
6659    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6660        range.start >= self.excerpt.buffer_start_offset()
6661            && range.end <= self.excerpt.buffer_end_offset()
6662    }
6663
6664    pub fn max_buffer_row(&self) -> u32 {
6665        self.excerpt.max_buffer_row
6666    }
6667}
6668
6669impl ExcerptId {
6670    pub fn min() -> Self {
6671        Self(0)
6672    }
6673
6674    pub fn max() -> Self {
6675        Self(usize::MAX)
6676    }
6677
6678    pub fn to_proto(&self) -> u64 {
6679        self.0 as _
6680    }
6681
6682    pub fn from_proto(proto: u64) -> Self {
6683        Self(proto as _)
6684    }
6685
6686    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6687        let a = snapshot.excerpt_locator_for_id(*self);
6688        let b = snapshot.excerpt_locator_for_id(*other);
6689        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6690    }
6691}
6692
6693impl From<ExcerptId> for usize {
6694    fn from(val: ExcerptId) -> Self {
6695        val.0
6696    }
6697}
6698
6699impl fmt::Debug for Excerpt {
6700    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6701        f.debug_struct("Excerpt")
6702            .field("id", &self.id)
6703            .field("locator", &self.locator)
6704            .field("buffer_id", &self.buffer_id)
6705            .field("range", &self.range)
6706            .field("text_summary", &self.text_summary)
6707            .field("has_trailing_newline", &self.has_trailing_newline)
6708            .finish()
6709    }
6710}
6711
6712impl sum_tree::Item for Excerpt {
6713    type Summary = ExcerptSummary;
6714
6715    fn summary(&self, _cx: &()) -> Self::Summary {
6716        let mut text = self.text_summary;
6717        if self.has_trailing_newline {
6718            text += TextSummary::from("\n");
6719        }
6720        ExcerptSummary {
6721            excerpt_id: self.id,
6722            excerpt_locator: self.locator.clone(),
6723            widest_line_number: self.max_buffer_row,
6724            text,
6725        }
6726    }
6727}
6728
6729impl sum_tree::Item for ExcerptIdMapping {
6730    type Summary = ExcerptId;
6731
6732    fn summary(&self, _cx: &()) -> Self::Summary {
6733        self.id
6734    }
6735}
6736
6737impl sum_tree::KeyedItem for ExcerptIdMapping {
6738    type Key = ExcerptId;
6739
6740    fn key(&self) -> Self::Key {
6741        self.id
6742    }
6743}
6744
6745impl DiffTransform {
6746    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6747        match self {
6748            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6749            DiffTransform::BufferContent {
6750                inserted_hunk_info, ..
6751            } => *inserted_hunk_info,
6752        }
6753    }
6754}
6755
6756impl sum_tree::Item for DiffTransform {
6757    type Summary = DiffTransformSummary;
6758
6759    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6760        match self {
6761            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6762                input: *summary,
6763                output: *summary,
6764            },
6765            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6766                input: TextSummary::default(),
6767                output: *summary,
6768            },
6769        }
6770    }
6771}
6772
6773impl DiffTransformSummary {
6774    fn excerpt_len(&self) -> ExcerptOffset {
6775        ExcerptOffset::new(self.input.len)
6776    }
6777}
6778
6779impl sum_tree::Summary for DiffTransformSummary {
6780    type Context = ();
6781
6782    fn zero(_: &Self::Context) -> Self {
6783        DiffTransformSummary {
6784            input: TextSummary::default(),
6785            output: TextSummary::default(),
6786        }
6787    }
6788
6789    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6790        self.input += &summary.input;
6791        self.output += &summary.output;
6792    }
6793}
6794
6795impl sum_tree::Summary for ExcerptId {
6796    type Context = ();
6797
6798    fn zero(_cx: &()) -> Self {
6799        Default::default()
6800    }
6801
6802    fn add_summary(&mut self, other: &Self, _: &()) {
6803        *self = *other;
6804    }
6805}
6806
6807impl sum_tree::Summary for ExcerptSummary {
6808    type Context = ();
6809
6810    fn zero(_cx: &()) -> Self {
6811        Default::default()
6812    }
6813
6814    fn add_summary(&mut self, summary: &Self, _: &()) {
6815        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6816        self.excerpt_locator = summary.excerpt_locator.clone();
6817        self.text.add_summary(&summary.text, &());
6818        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6819    }
6820}
6821
6822impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6823    fn zero(_cx: &()) -> Self {
6824        Default::default()
6825    }
6826
6827    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6828        self.value += summary.text.len;
6829    }
6830}
6831
6832impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6833    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6834        Ord::cmp(&self.value, &cursor_location.text.len)
6835    }
6836}
6837
6838impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6839    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6840        Ord::cmp(&Some(self), cursor_location)
6841    }
6842}
6843
6844impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6845    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6846        Ord::cmp(self, &cursor_location.excerpt_locator)
6847    }
6848}
6849
6850impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6851    fn zero(_cx: &()) -> Self {
6852        Default::default()
6853    }
6854
6855    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6856        self.value += summary.text.lines;
6857    }
6858}
6859
6860impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6861    for ExcerptDimension<D>
6862{
6863    fn zero(_: &()) -> Self {
6864        ExcerptDimension(D::default())
6865    }
6866
6867    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6868        self.0.add_assign(&D::from_text_summary(&summary.text))
6869    }
6870}
6871
6872impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6873    fn zero(_cx: &()) -> Self {
6874        Default::default()
6875    }
6876
6877    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6878        *self = Some(&summary.excerpt_locator);
6879    }
6880}
6881
6882impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6883    fn zero(_cx: &()) -> Self {
6884        Default::default()
6885    }
6886
6887    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6888        *self = Some(summary.excerpt_id);
6889    }
6890}
6891
6892#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6893struct ExcerptDimension<T>(T);
6894
6895#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6896struct OutputDimension<T>(T);
6897
6898impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6899    fn zero(_: &()) -> Self {
6900        ExcerptOffset::new(0)
6901    }
6902
6903    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6904        self.value += summary.input.len;
6905    }
6906}
6907
6908impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6909    fn zero(_: &()) -> Self {
6910        ExcerptPoint::new(0, 0)
6911    }
6912
6913    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6914        self.value += summary.input.lines;
6915    }
6916}
6917
6918impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6919    for ExcerptDimension<D>
6920{
6921    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6922        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6923    }
6924}
6925
6926impl<D: TextDimension + Ord>
6927    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6928    for ExcerptDimension<D>
6929{
6930    fn cmp(
6931        &self,
6932        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6933        _: &(),
6934    ) -> cmp::Ordering {
6935        Ord::cmp(&self.0, &cursor_location.1 .0)
6936    }
6937}
6938
6939impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6940    fn zero(_: &()) -> Self {
6941        ExcerptDimension(D::default())
6942    }
6943
6944    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6945        self.0.add_assign(&D::from_text_summary(&summary.input))
6946    }
6947}
6948
6949impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6950    fn zero(_: &()) -> Self {
6951        OutputDimension(D::default())
6952    }
6953
6954    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6955        self.0.add_assign(&D::from_text_summary(&summary.output))
6956    }
6957}
6958
6959impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6960    fn zero(_: &()) -> Self {
6961        TextSummary::default()
6962    }
6963
6964    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6965        *self += summary.output
6966    }
6967}
6968
6969impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6970    fn zero(_: &()) -> Self {
6971        0
6972    }
6973
6974    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6975        *self += summary.output.len
6976    }
6977}
6978
6979impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6980    fn zero(_: &()) -> Self {
6981        Point::new(0, 0)
6982    }
6983
6984    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6985        *self += summary.output.lines
6986    }
6987}
6988
6989impl MultiBufferRows<'_> {
6990    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6991        self.point = Point::new(row, 0);
6992        self.cursor.seek(&self.point);
6993    }
6994}
6995
6996impl Iterator for MultiBufferRows<'_> {
6997    type Item = RowInfo;
6998
6999    fn next(&mut self) -> Option<Self::Item> {
7000        if self.is_empty && self.point.row == 0 {
7001            self.point += Point::new(1, 0);
7002            return Some(RowInfo {
7003                buffer_id: None,
7004                buffer_row: Some(0),
7005                multibuffer_row: Some(MultiBufferRow(0)),
7006                diff_status: None,
7007            });
7008        }
7009
7010        let mut region = self.cursor.region()?;
7011        while self.point >= region.range.end {
7012            self.cursor.next();
7013            if let Some(next_region) = self.cursor.region() {
7014                region = next_region;
7015            } else {
7016                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7017                    let multibuffer_row = MultiBufferRow(self.point.row);
7018                    self.point += Point::new(1, 0);
7019                    let last_excerpt = self
7020                        .cursor
7021                        .excerpts
7022                        .item()
7023                        .or(self.cursor.excerpts.prev_item())?;
7024                    let last_row = last_excerpt
7025                        .range
7026                        .context
7027                        .end
7028                        .to_point(&last_excerpt.buffer)
7029                        .row;
7030                    return Some(RowInfo {
7031                        buffer_id: Some(last_excerpt.buffer_id),
7032                        buffer_row: Some(last_row),
7033                        multibuffer_row: Some(multibuffer_row),
7034                        diff_status: None,
7035                    });
7036                } else {
7037                    return None;
7038                }
7039            };
7040        }
7041
7042        let overshoot = self.point - region.range.start;
7043        let buffer_point = region.buffer_range.start + overshoot;
7044        let result = Some(RowInfo {
7045            buffer_id: Some(region.buffer.remote_id()),
7046            buffer_row: Some(buffer_point.row),
7047            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7048            diff_status: region
7049                .diff_hunk_status
7050                .filter(|_| self.point < region.range.end),
7051        });
7052        self.point += Point::new(1, 0);
7053        result
7054    }
7055}
7056
7057impl<'a> MultiBufferChunks<'a> {
7058    pub fn offset(&self) -> usize {
7059        self.range.start
7060    }
7061
7062    pub fn seek(&mut self, range: Range<usize>) {
7063        self.diff_transforms.seek(&range.end, Bias::Right, &());
7064        let mut excerpt_end = self.diff_transforms.start().1;
7065        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7066            let overshoot = range.end - self.diff_transforms.start().0;
7067            excerpt_end.value += overshoot;
7068        }
7069
7070        self.diff_transforms.seek(&range.start, Bias::Right, &());
7071        let mut excerpt_start = self.diff_transforms.start().1;
7072        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7073            let overshoot = range.start - self.diff_transforms.start().0;
7074            excerpt_start.value += overshoot;
7075        }
7076
7077        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7078        self.buffer_chunk.take();
7079        self.range = range;
7080    }
7081
7082    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7083        self.excerpt_offset_range = new_range.clone();
7084        self.excerpts.seek(&new_range.start, Bias::Right, &());
7085        if let Some(excerpt) = self.excerpts.item() {
7086            let excerpt_start = *self.excerpts.start();
7087            if let Some(excerpt_chunks) = self
7088                .excerpt_chunks
7089                .as_mut()
7090                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7091            {
7092                excerpt.seek_chunks(
7093                    excerpt_chunks,
7094                    (self.excerpt_offset_range.start - excerpt_start).value
7095                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7096                );
7097            } else {
7098                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7099                    (self.excerpt_offset_range.start - excerpt_start).value
7100                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7101                    self.language_aware,
7102                ));
7103            }
7104        } else {
7105            self.excerpt_chunks = None;
7106        }
7107    }
7108
7109    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7110        loop {
7111            if self.excerpt_offset_range.is_empty() {
7112                return None;
7113            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7114                self.excerpt_offset_range.start.value += chunk.text.len();
7115                return Some(chunk);
7116            } else {
7117                self.excerpts.next(&());
7118                let excerpt = self.excerpts.item()?;
7119                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7120                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7121                    self.language_aware,
7122                ));
7123            }
7124        }
7125    }
7126}
7127
7128impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7129    type Item = &'a str;
7130
7131    fn next(&mut self) -> Option<Self::Item> {
7132        let mut region = self.cursor.region()?;
7133        if self.offset == region.range.start {
7134            self.cursor.prev();
7135            region = self.cursor.region()?;
7136            let start_overshoot = self.start.saturating_sub(region.range.start);
7137            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7138                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7139            ));
7140        }
7141
7142        if self.offset == region.range.end && region.has_trailing_newline {
7143            self.offset -= 1;
7144            Some("\n")
7145        } else {
7146            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7147            self.offset -= chunk.len();
7148            Some(chunk)
7149        }
7150    }
7151}
7152
7153impl<'a> Iterator for MultiBufferChunks<'a> {
7154    type Item = Chunk<'a>;
7155
7156    fn next(&mut self) -> Option<Chunk<'a>> {
7157        if self.range.start >= self.range.end {
7158            return None;
7159        }
7160        if self.range.start == self.diff_transforms.end(&()).0 {
7161            self.diff_transforms.next(&());
7162        }
7163
7164        let diff_transform_start = self.diff_transforms.start().0;
7165        let diff_transform_end = self.diff_transforms.end(&()).0;
7166        debug_assert!(self.range.start < diff_transform_end);
7167
7168        let diff_transform = self.diff_transforms.item()?;
7169        match diff_transform {
7170            DiffTransform::BufferContent { .. } => {
7171                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7172                    chunk
7173                } else {
7174                    let chunk = self.next_excerpt_chunk().unwrap();
7175                    self.buffer_chunk.insert(chunk)
7176                };
7177
7178                let chunk_end = self.range.start + chunk.text.len();
7179                let diff_transform_end = diff_transform_end.min(self.range.end);
7180
7181                if diff_transform_end < chunk_end {
7182                    let (before, after) =
7183                        chunk.text.split_at(diff_transform_end - self.range.start);
7184                    self.range.start = diff_transform_end;
7185                    chunk.text = after;
7186                    Some(Chunk {
7187                        text: before,
7188                        ..chunk.clone()
7189                    })
7190                } else {
7191                    self.range.start = chunk_end;
7192                    self.buffer_chunk.take()
7193                }
7194            }
7195            DiffTransform::DeletedHunk {
7196                buffer_id,
7197                base_text_byte_range,
7198                has_trailing_newline,
7199                ..
7200            } => {
7201                let base_text_start =
7202                    base_text_byte_range.start + self.range.start - diff_transform_start;
7203                let base_text_end =
7204                    base_text_byte_range.start + self.range.end - diff_transform_start;
7205                let base_text_end = base_text_end.min(base_text_byte_range.end);
7206
7207                let mut chunks = if let Some((_, mut chunks)) = self
7208                    .diff_base_chunks
7209                    .take()
7210                    .filter(|(id, _)| id == buffer_id)
7211                {
7212                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7213                    {
7214                        chunks.seek(base_text_start..base_text_end);
7215                    }
7216                    chunks
7217                } else {
7218                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7219                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7220                };
7221
7222                let chunk = if let Some(chunk) = chunks.next() {
7223                    self.range.start += chunk.text.len();
7224                    self.diff_base_chunks = Some((*buffer_id, chunks));
7225                    chunk
7226                } else {
7227                    debug_assert!(has_trailing_newline);
7228                    self.range.start += "\n".len();
7229                    Chunk {
7230                        text: "\n",
7231                        ..Default::default()
7232                    }
7233                };
7234                Some(chunk)
7235            }
7236        }
7237    }
7238}
7239
7240impl MultiBufferBytes<'_> {
7241    fn consume(&mut self, len: usize) {
7242        self.range.start += len;
7243        self.chunk = &self.chunk[len..];
7244
7245        if !self.range.is_empty() && self.chunk.is_empty() {
7246            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7247                self.chunk = chunk;
7248            } else if self.has_trailing_newline {
7249                self.has_trailing_newline = false;
7250                self.chunk = b"\n";
7251            } else {
7252                self.cursor.next();
7253                if let Some(region) = self.cursor.region() {
7254                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7255                        region.buffer_range.start
7256                            ..(region.buffer_range.start + self.range.end - region.range.start)
7257                                .min(region.buffer_range.end),
7258                    );
7259                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7260                    self.excerpt_bytes = Some(excerpt_bytes);
7261                    self.has_trailing_newline =
7262                        region.has_trailing_newline && self.range.end >= region.range.end;
7263                    if self.chunk.is_empty() && self.has_trailing_newline {
7264                        self.has_trailing_newline = false;
7265                        self.chunk = b"\n";
7266                    }
7267                }
7268            }
7269        }
7270    }
7271}
7272
7273impl<'a> Iterator for MultiBufferBytes<'a> {
7274    type Item = &'a [u8];
7275
7276    fn next(&mut self) -> Option<Self::Item> {
7277        let chunk = self.chunk;
7278        if chunk.is_empty() {
7279            None
7280        } else {
7281            self.consume(chunk.len());
7282            Some(chunk)
7283        }
7284    }
7285}
7286
7287impl io::Read for MultiBufferBytes<'_> {
7288    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7289        let len = cmp::min(buf.len(), self.chunk.len());
7290        buf[..len].copy_from_slice(&self.chunk[..len]);
7291        if len > 0 {
7292            self.consume(len);
7293        }
7294        Ok(len)
7295    }
7296}
7297
7298impl io::Read for ReversedMultiBufferBytes<'_> {
7299    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7300        let len = cmp::min(buf.len(), self.chunk.len());
7301        buf[..len].copy_from_slice(&self.chunk[..len]);
7302        buf[..len].reverse();
7303        if len > 0 {
7304            self.range.end -= len;
7305            self.chunk = &self.chunk[..self.chunk.len() - len];
7306            if !self.range.is_empty() && self.chunk.is_empty() {
7307                if let Some(chunk) = self.chunks.next() {
7308                    self.chunk = chunk.as_bytes();
7309                }
7310            }
7311        }
7312        Ok(len)
7313    }
7314}
7315
7316impl<'a> Iterator for ExcerptChunks<'a> {
7317    type Item = Chunk<'a>;
7318
7319    fn next(&mut self) -> Option<Self::Item> {
7320        if let Some(chunk) = self.content_chunks.next() {
7321            return Some(chunk);
7322        }
7323
7324        if self.footer_height > 0 {
7325            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7326            self.footer_height = 0;
7327            return Some(Chunk {
7328                text,
7329                ..Default::default()
7330            });
7331        }
7332
7333        None
7334    }
7335}
7336
7337impl ToOffset for Point {
7338    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7339        snapshot.point_to_offset(*self)
7340    }
7341}
7342
7343impl ToOffset for usize {
7344    #[track_caller]
7345    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7346        assert!(*self <= snapshot.len(), "offset is out of range");
7347        *self
7348    }
7349}
7350
7351impl ToOffset for OffsetUtf16 {
7352    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7353        snapshot.offset_utf16_to_offset(*self)
7354    }
7355}
7356
7357impl ToOffset for PointUtf16 {
7358    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7359        snapshot.point_utf16_to_offset(*self)
7360    }
7361}
7362
7363impl ToOffsetUtf16 for OffsetUtf16 {
7364    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7365        *self
7366    }
7367}
7368
7369impl ToOffsetUtf16 for usize {
7370    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7371        snapshot.offset_to_offset_utf16(*self)
7372    }
7373}
7374
7375impl ToPoint for usize {
7376    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7377        snapshot.offset_to_point(*self)
7378    }
7379}
7380
7381impl ToPoint for Point {
7382    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7383        *self
7384    }
7385}
7386
7387impl ToPointUtf16 for usize {
7388    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7389        snapshot.offset_to_point_utf16(*self)
7390    }
7391}
7392
7393impl ToPointUtf16 for Point {
7394    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7395        snapshot.point_to_point_utf16(*self)
7396    }
7397}
7398
7399impl ToPointUtf16 for PointUtf16 {
7400    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7401        *self
7402    }
7403}
7404
7405impl From<ExcerptId> for EntityId {
7406    fn from(id: ExcerptId) -> Self {
7407        EntityId::from(id.0 as u64)
7408    }
7409}
7410
7411pub fn build_excerpt_ranges<T>(
7412    buffer: &BufferSnapshot,
7413    ranges: &[Range<T>],
7414    context_line_count: u32,
7415) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7416where
7417    T: text::ToPoint,
7418{
7419    let max_point = buffer.max_point();
7420    let mut range_counts = Vec::new();
7421    let mut excerpt_ranges = Vec::new();
7422    let mut range_iter = ranges
7423        .iter()
7424        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7425        .peekable();
7426    while let Some(range) = range_iter.next() {
7427        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7428        let row = (range.end.row + context_line_count).min(max_point.row);
7429        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7430
7431        let mut ranges_in_excerpt = 1;
7432
7433        while let Some(next_range) = range_iter.peek() {
7434            if next_range.start.row <= excerpt_end.row + context_line_count {
7435                let row = (next_range.end.row + context_line_count).min(max_point.row);
7436                excerpt_end = Point::new(row, buffer.line_len(row));
7437
7438                ranges_in_excerpt += 1;
7439                range_iter.next();
7440            } else {
7441                break;
7442            }
7443        }
7444
7445        excerpt_ranges.push(ExcerptRange {
7446            context: excerpt_start..excerpt_end,
7447            primary: Some(range),
7448        });
7449        range_counts.push(ranges_in_excerpt);
7450    }
7451
7452    (excerpt_ranges, range_counts)
7453}