multi_buffer.rs

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