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                || region.range.start == range.end && region.range.start > range.start
3546            {
3547                return None;
3548            }
3549            cursor.next_excerpt();
3550            Some(region.excerpt.buffer_id)
3551        })
3552    }
3553
3554    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3555        &self,
3556        ranges: impl Iterator<Item = Range<T>>,
3557    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3558        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3559    }
3560
3561    pub fn range_to_buffer_ranges<T: ToOffset>(
3562        &self,
3563        range: Range<T>,
3564    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3565        let start = range.start.to_offset(&self);
3566        let end = range.end.to_offset(&self);
3567
3568        let mut cursor = self.cursor::<usize>();
3569        cursor.seek(&start);
3570
3571        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3572        while let Some(region) = cursor.region() {
3573            if region.range.start > end {
3574                break;
3575            }
3576            if region.is_main_buffer {
3577                let start_overshoot = start.saturating_sub(region.range.start);
3578                let end_overshoot = end.saturating_sub(region.range.start);
3579                let start = region
3580                    .buffer_range
3581                    .end
3582                    .min(region.buffer_range.start + start_overshoot);
3583                let end = region
3584                    .buffer_range
3585                    .end
3586                    .min(region.buffer_range.start + end_overshoot);
3587                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3588                    *excerpt_id == region.excerpt.id && prev_range.end == start
3589                }) {
3590                    prev.1.end = end;
3591                } else {
3592                    result.push((region.buffer, start..end, region.excerpt.id));
3593                }
3594            }
3595            cursor.next();
3596        }
3597        result
3598    }
3599
3600    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3601        &self,
3602        range: Range<T>,
3603    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3604        let start = range.start.to_offset(&self);
3605        let end = range.end.to_offset(&self);
3606
3607        let mut cursor = self.cursor::<usize>();
3608        cursor.seek(&start);
3609
3610        std::iter::from_fn(move || {
3611            let region = cursor.region()?;
3612            if region.range.start > end {
3613                return None;
3614            }
3615            let start_overshoot = start.saturating_sub(region.range.start);
3616            let end_overshoot = end.saturating_sub(region.range.start);
3617            let start = region
3618                .buffer_range
3619                .end
3620                .min(region.buffer_range.start + start_overshoot);
3621            let end = region
3622                .buffer_range
3623                .end
3624                .min(region.buffer_range.start + end_overshoot);
3625
3626            let region_excerpt_id = region.excerpt.id;
3627            let deleted_hunk_anchor = if region.is_main_buffer {
3628                None
3629            } else {
3630                Some(self.anchor_before(region.range.start))
3631            };
3632            let result = (
3633                region.buffer,
3634                start..end,
3635                region_excerpt_id,
3636                deleted_hunk_anchor,
3637            );
3638            cursor.next();
3639            Some(result)
3640        })
3641    }
3642
3643    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3644    /// coordinates.
3645    ///
3646    /// The given callback will be called for every excerpt intersecting the given range. It will
3647    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3648    /// The callback should return an iterator of metadata items from that buffer, each paired
3649    /// with a buffer range.
3650    ///
3651    /// The returned iterator yields each of these metadata items, paired with its range in
3652    /// multi-buffer coordinates.
3653    fn lift_buffer_metadata<'a, D, M, I>(
3654        &'a self,
3655        query_range: Range<D>,
3656        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3657    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3658    where
3659        I: Iterator<Item = (Range<D>, M)> + 'a,
3660        D: TextDimension + Ord + Sub<D, Output = D>,
3661    {
3662        let max_position = D::from_text_summary(&self.text_summary());
3663        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3664        let mut cursor = self.cursor::<D>();
3665
3666        // Find the excerpt and buffer offset where the given range ends.
3667        cursor.seek(&query_range.end);
3668        let mut range_end = None;
3669        while let Some(region) = cursor.region() {
3670            if region.is_main_buffer {
3671                let mut buffer_end = region.buffer_range.start;
3672                let overshoot = if query_range.end > region.range.start {
3673                    query_range.end - region.range.start
3674                } else {
3675                    D::default()
3676                };
3677                buffer_end.add_assign(&overshoot);
3678                range_end = Some((region.excerpt.id, buffer_end));
3679                break;
3680            }
3681            cursor.next();
3682        }
3683
3684        cursor.seek(&query_range.start);
3685
3686        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3687            if region.range.start > D::zero(&()) {
3688                cursor.prev()
3689            }
3690        }
3691
3692        iter::from_fn(move || loop {
3693            let excerpt = cursor.excerpt()?;
3694
3695            // If we have already retrieved metadata for this excerpt, continue to use it.
3696            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3697                .as_mut()
3698                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3699            {
3700                Some(metadata)
3701            }
3702            // Otherwise, compute the intersection of the input range with the excerpt's range,
3703            // and retrieve the metadata for the resulting range.
3704            else {
3705                let region = cursor.region()?;
3706                let mut buffer_start;
3707                if region.is_main_buffer {
3708                    buffer_start = region.buffer_range.start;
3709                    if query_range.start > region.range.start {
3710                        let overshoot = query_range.start - region.range.start;
3711                        buffer_start.add_assign(&overshoot);
3712                    }
3713                    buffer_start = buffer_start.min(region.buffer_range.end);
3714                } else {
3715                    buffer_start = cursor.main_buffer_position()?;
3716                };
3717                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3718                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3719                    if excerpt.id == end_excerpt_id {
3720                        buffer_end = buffer_end.min(end_buffer_offset);
3721                    }
3722                }
3723
3724                if let Some(iterator) =
3725                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3726                {
3727                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3728                } else {
3729                    None
3730                }
3731            };
3732
3733            // Visit each metadata item.
3734            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3735            {
3736                // Find the multibuffer regions that contain the start and end of
3737                // the metadata item's range.
3738                if metadata_buffer_range.start > D::default() {
3739                    while let Some(region) = cursor.region() {
3740                        if region.is_main_buffer
3741                            && (region.buffer_range.end >= metadata_buffer_range.start
3742                                || cursor.is_at_end_of_excerpt())
3743                        {
3744                            break;
3745                        }
3746                        cursor.next();
3747                    }
3748                }
3749                let start_region = cursor.region()?;
3750                while let Some(region) = cursor.region() {
3751                    if region.is_main_buffer
3752                        && (region.buffer_range.end > metadata_buffer_range.end
3753                            || cursor.is_at_end_of_excerpt())
3754                    {
3755                        break;
3756                    }
3757                    cursor.next();
3758                }
3759                let end_region = cursor.region();
3760
3761                // Convert the metadata item's range into multibuffer coordinates.
3762                let mut start_position = start_region.range.start;
3763                let region_buffer_start = start_region.buffer_range.start;
3764                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3765                {
3766                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3767                    start_position = start_position.min(start_region.range.end);
3768                }
3769
3770                let mut end_position = max_position;
3771                if let Some(end_region) = &end_region {
3772                    end_position = end_region.range.start;
3773                    debug_assert!(end_region.is_main_buffer);
3774                    let region_buffer_start = end_region.buffer_range.start;
3775                    if metadata_buffer_range.end > region_buffer_start {
3776                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3777                    }
3778                    end_position = end_position.min(end_region.range.end);
3779                }
3780
3781                if start_position <= query_range.end && end_position >= query_range.start {
3782                    return Some((start_position..end_position, metadata, excerpt));
3783                }
3784            }
3785            // When there are no more metadata items for this excerpt, move to the next excerpt.
3786            else {
3787                current_excerpt_metadata.take();
3788                cursor.next_excerpt();
3789            }
3790        })
3791    }
3792
3793    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3794        let offset = position.to_offset(self);
3795
3796        // Go to the region containing the given offset.
3797        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3798        cursor.seek(&DimensionPair {
3799            key: offset,
3800            value: None,
3801        });
3802        let mut region = cursor.region()?;
3803        if region.range.start.key == offset || !region.is_main_buffer {
3804            cursor.prev();
3805            region = cursor.region()?;
3806        }
3807
3808        // Find the corresponding buffer offset.
3809        let overshoot = if region.is_main_buffer {
3810            offset - region.range.start.key
3811        } else {
3812            0
3813        };
3814        let mut max_buffer_offset = region
3815            .buffer
3816            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3817
3818        loop {
3819            let excerpt = cursor.excerpt()?;
3820            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3821            let buffer_offset = excerpt_end.min(max_buffer_offset);
3822            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3823            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3824
3825            if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3826                for hunk in diff.hunks_intersecting_range_rev(
3827                    excerpt.range.context.start..buffer_end,
3828                    &excerpt.buffer,
3829                ) {
3830                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3831                    if hunk.row_range.end >= buffer_end_row {
3832                        continue;
3833                    }
3834
3835                    let hunk_start = Point::new(hunk.row_range.start, 0);
3836                    let hunk_end = Point::new(hunk.row_range.end, 0);
3837
3838                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3839                        key: hunk_range.start,
3840                        value: None,
3841                    });
3842
3843                    let mut region = cursor.region()?;
3844                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3845                    {
3846                        cursor.prev();
3847                        region = cursor.region()?;
3848                    }
3849
3850                    let overshoot = if region.is_main_buffer {
3851                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3852                    } else {
3853                        Point::zero()
3854                    };
3855                    let start = region.range.start.value.unwrap() + overshoot;
3856
3857                    while let Some(region) = cursor.region() {
3858                        if !region.is_main_buffer
3859                            || region.buffer_range.end.value.unwrap() <= hunk_end
3860                        {
3861                            cursor.next();
3862                        } else {
3863                            break;
3864                        }
3865                    }
3866
3867                    let end = if let Some(region) = cursor.region() {
3868                        let overshoot = if region.is_main_buffer {
3869                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3870                        } else {
3871                            Point::zero()
3872                        };
3873                        region.range.start.value.unwrap() + overshoot
3874                    } else {
3875                        self.max_point()
3876                    };
3877
3878                    return Some(MultiBufferDiffHunk {
3879                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3880                        buffer_id: excerpt.buffer_id,
3881                        excerpt_id: excerpt.id,
3882                        buffer_range: hunk.buffer_range.clone(),
3883                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3884                        secondary_status: hunk.secondary_status,
3885                    });
3886                }
3887            }
3888
3889            cursor.prev_excerpt();
3890            max_buffer_offset = usize::MAX;
3891        }
3892    }
3893
3894    pub fn has_diff_hunks(&self) -> bool {
3895        self.diffs.values().any(|diff| !diff.is_empty())
3896    }
3897
3898    pub fn surrounding_word<T: ToOffset>(
3899        &self,
3900        start: T,
3901        for_completion: bool,
3902    ) -> (Range<usize>, Option<CharKind>) {
3903        let mut start = start.to_offset(self);
3904        let mut end = start;
3905        let mut next_chars = self.chars_at(start).peekable();
3906        let mut prev_chars = self.reversed_chars_at(start).peekable();
3907
3908        let classifier = self
3909            .char_classifier_at(start)
3910            .for_completion(for_completion);
3911
3912        let word_kind = cmp::max(
3913            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3914            next_chars.peek().copied().map(|c| classifier.kind(c)),
3915        );
3916
3917        for ch in prev_chars {
3918            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3919                start -= ch.len_utf8();
3920            } else {
3921                break;
3922            }
3923        }
3924
3925        for ch in next_chars {
3926            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3927                end += ch.len_utf8();
3928            } else {
3929                break;
3930            }
3931        }
3932
3933        (start..end, word_kind)
3934    }
3935
3936    pub fn is_singleton(&self) -> bool {
3937        self.singleton
3938    }
3939
3940    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3941        if self.singleton {
3942            self.excerpts
3943                .iter()
3944                .next()
3945                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3946        } else {
3947            None
3948        }
3949    }
3950
3951    pub fn len(&self) -> usize {
3952        self.diff_transforms.summary().output.len
3953    }
3954
3955    pub fn is_empty(&self) -> bool {
3956        self.excerpts.summary().text.len == 0
3957    }
3958
3959    pub fn widest_line_number(&self) -> u32 {
3960        self.excerpts.summary().widest_line_number + 1
3961    }
3962
3963    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3964        let range = range.start.to_offset(self)..range.end.to_offset(self);
3965        let mut excerpts = self.cursor::<usize>();
3966        excerpts.seek(&range.start);
3967
3968        let mut chunk;
3969        let mut has_trailing_newline;
3970        let excerpt_bytes;
3971        if let Some(region) = excerpts.region() {
3972            let mut bytes = region.buffer.bytes_in_range(
3973                region.buffer_range.start + range.start - region.range.start
3974                    ..(region.buffer_range.start + range.end - region.range.start)
3975                        .min(region.buffer_range.end),
3976            );
3977            chunk = bytes.next().unwrap_or(&[][..]);
3978            excerpt_bytes = Some(bytes);
3979            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3980            if chunk.is_empty() && has_trailing_newline {
3981                chunk = b"\n";
3982                has_trailing_newline = false;
3983            }
3984        } else {
3985            chunk = &[][..];
3986            excerpt_bytes = None;
3987            has_trailing_newline = false;
3988        };
3989
3990        MultiBufferBytes {
3991            range,
3992            cursor: excerpts,
3993            excerpt_bytes,
3994            has_trailing_newline,
3995            chunk,
3996        }
3997    }
3998
3999    pub fn reversed_bytes_in_range<T: ToOffset>(
4000        &self,
4001        range: Range<T>,
4002    ) -> ReversedMultiBufferBytes {
4003        let range = range.start.to_offset(self)..range.end.to_offset(self);
4004        let mut chunks = self.reversed_chunks_in_range(range.clone());
4005        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4006        ReversedMultiBufferBytes {
4007            range,
4008            chunks,
4009            chunk,
4010        }
4011    }
4012
4013    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4014        let mut cursor = self.cursor::<Point>();
4015        cursor.seek(&Point::new(start_row.0, 0));
4016        let mut result = MultiBufferRows {
4017            point: Point::new(0, 0),
4018            is_empty: self.excerpts.is_empty(),
4019            cursor,
4020        };
4021        result.seek(start_row);
4022        result
4023    }
4024
4025    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4026        let mut chunks = MultiBufferChunks {
4027            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4028            range: 0..0,
4029            excerpts: self.excerpts.cursor(&()),
4030            diff_transforms: self.diff_transforms.cursor(&()),
4031            diffs: &self.diffs,
4032            diff_base_chunks: None,
4033            excerpt_chunks: None,
4034            buffer_chunk: None,
4035            language_aware,
4036        };
4037        let range = range.start.to_offset(self)..range.end.to_offset(self);
4038        chunks.seek(range);
4039        chunks
4040    }
4041
4042    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4043        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4044    }
4045
4046    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4047        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4048    }
4049
4050    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4051        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4052    }
4053
4054    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4055        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4056            buffer.clip_point_utf16(Unclipped(point), bias)
4057        })
4058    }
4059
4060    pub fn offset_to_point(&self, offset: usize) -> Point {
4061        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4062    }
4063
4064    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4065        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4066    }
4067
4068    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4069        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4070    }
4071
4072    pub fn point_to_offset(&self, point: Point) -> usize {
4073        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4074    }
4075
4076    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4077        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4078    }
4079
4080    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4081        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4082    }
4083
4084    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4085        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4086    }
4087
4088    fn clip_dimension<D>(
4089        &self,
4090        position: D,
4091        bias: Bias,
4092        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4093    ) -> D
4094    where
4095        D: TextDimension + Ord + Sub<D, Output = D>,
4096    {
4097        let mut cursor = self.cursor();
4098        cursor.seek(&position);
4099        if let Some(region) = cursor.region() {
4100            if position >= region.range.end {
4101                return region.range.end;
4102            }
4103            let overshoot = position - region.range.start;
4104            let mut buffer_position = region.buffer_range.start;
4105            buffer_position.add_assign(&overshoot);
4106            let clipped_buffer_position =
4107                clip_buffer_position(&region.buffer, buffer_position, bias);
4108            let mut position = region.range.start;
4109            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4110            position
4111        } else {
4112            D::from_text_summary(&self.text_summary())
4113        }
4114    }
4115
4116    fn convert_dimension<D1, D2>(
4117        &self,
4118        key: D1,
4119        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4120    ) -> D2
4121    where
4122        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4123        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4124    {
4125        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4126        cursor.seek(&DimensionPair { key, value: None });
4127        if let Some(region) = cursor.region() {
4128            if key >= region.range.end.key {
4129                return region.range.end.value.unwrap();
4130            }
4131            let start_key = region.range.start.key;
4132            let start_value = region.range.start.value.unwrap();
4133            let buffer_start_key = region.buffer_range.start.key;
4134            let buffer_start_value = region.buffer_range.start.value.unwrap();
4135            let mut buffer_key = buffer_start_key;
4136            buffer_key.add_assign(&(key - start_key));
4137            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4138            let mut result = start_value;
4139            result.add_assign(&(buffer_value - buffer_start_value));
4140            result
4141        } else {
4142            D2::from_text_summary(&self.text_summary())
4143        }
4144    }
4145
4146    pub fn point_to_buffer_offset<T: ToOffset>(
4147        &self,
4148        point: T,
4149    ) -> Option<(&BufferSnapshot, usize)> {
4150        let offset = point.to_offset(self);
4151        let mut cursor = self.cursor::<usize>();
4152        cursor.seek(&offset);
4153        let region = cursor.region()?;
4154        let overshoot = offset - region.range.start;
4155        let buffer_offset = region.buffer_range.start + overshoot;
4156        Some((region.buffer, buffer_offset))
4157    }
4158
4159    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4160        let mut cursor = self.cursor::<Point>();
4161        cursor.seek(&point);
4162        let region = cursor.region()?;
4163        let overshoot = point - region.range.start;
4164        let buffer_offset = region.buffer_range.start + overshoot;
4165        Some((region.buffer, buffer_offset, region.is_main_buffer))
4166    }
4167
4168    pub fn suggested_indents(
4169        &self,
4170        rows: impl IntoIterator<Item = u32>,
4171        cx: &App,
4172    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4173        let mut result = BTreeMap::new();
4174
4175        let mut rows_for_excerpt = Vec::new();
4176        let mut cursor = self.cursor::<Point>();
4177        let mut rows = rows.into_iter().peekable();
4178        let mut prev_row = u32::MAX;
4179        let mut prev_language_indent_size = IndentSize::default();
4180
4181        while let Some(row) = rows.next() {
4182            cursor.seek(&Point::new(row, 0));
4183            let Some(region) = cursor.region() else {
4184                continue;
4185            };
4186
4187            // Retrieve the language and indent size once for each disjoint region being indented.
4188            let single_indent_size = if row.saturating_sub(1) == prev_row {
4189                prev_language_indent_size
4190            } else {
4191                region
4192                    .buffer
4193                    .language_indent_size_at(Point::new(row, 0), cx)
4194            };
4195            prev_language_indent_size = single_indent_size;
4196            prev_row = row;
4197
4198            let start_buffer_row = region.buffer_range.start.row;
4199            let start_multibuffer_row = region.range.start.row;
4200            let end_multibuffer_row = region.range.end.row;
4201
4202            rows_for_excerpt.push(row);
4203            while let Some(next_row) = rows.peek().copied() {
4204                if end_multibuffer_row > next_row {
4205                    rows_for_excerpt.push(next_row);
4206                    rows.next();
4207                } else {
4208                    break;
4209                }
4210            }
4211
4212            let buffer_rows = rows_for_excerpt
4213                .drain(..)
4214                .map(|row| start_buffer_row + row - start_multibuffer_row);
4215            let buffer_indents = region
4216                .buffer
4217                .suggested_indents(buffer_rows, single_indent_size);
4218            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4219                (
4220                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4221                    indent,
4222                )
4223            });
4224            result.extend(multibuffer_indents);
4225        }
4226
4227        result
4228    }
4229
4230    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4231        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4232            let mut size = buffer.indent_size_for_line(range.start.row);
4233            size.len = size
4234                .len
4235                .min(range.end.column)
4236                .saturating_sub(range.start.column);
4237            size
4238        } else {
4239            IndentSize::spaces(0)
4240        }
4241    }
4242
4243    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4244        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4245            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4246        } else {
4247            LineIndent::spaces(0)
4248        }
4249    }
4250
4251    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4252        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4253
4254        if self.settings_at(0, cx).extend_comment_on_newline {
4255            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4256                let delimiters = language_scope.line_comment_prefixes();
4257                for delimiter in delimiters {
4258                    if *self
4259                        .chars_at(Point::new(row.0, indent.len() as u32))
4260                        .take(delimiter.chars().count())
4261                        .collect::<String>()
4262                        .as_str()
4263                        == **delimiter
4264                    {
4265                        indent.push_str(&delimiter);
4266                        break;
4267                    }
4268                }
4269            }
4270        }
4271
4272        indent
4273    }
4274
4275    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4276    where
4277        T: ToOffset,
4278    {
4279        for char in self.reversed_chars_at(position) {
4280            if !char.is_whitespace() {
4281                return false;
4282            }
4283            if char == '\n' {
4284                return true;
4285            }
4286        }
4287        return true;
4288    }
4289
4290    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4291        while row.0 > 0 {
4292            row.0 -= 1;
4293            if !self.is_line_blank(row) {
4294                return Some(row);
4295            }
4296        }
4297        None
4298    }
4299
4300    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4301        if let Some((_, range)) = self.buffer_line_for_row(row) {
4302            range.end.column - range.start.column
4303        } else {
4304            0
4305        }
4306    }
4307
4308    pub fn buffer_line_for_row(
4309        &self,
4310        row: MultiBufferRow,
4311    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4312        let mut cursor = self.cursor::<Point>();
4313        let point = Point::new(row.0, 0);
4314        cursor.seek(&point);
4315        let region = cursor.region()?;
4316        let overshoot = point.min(region.range.end) - region.range.start;
4317        let buffer_point = region.buffer_range.start + overshoot;
4318        if buffer_point.row > region.buffer_range.end.row {
4319            return None;
4320        }
4321        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4322        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4323            .min(region.buffer_range.end);
4324        Some((region.buffer, line_start..line_end))
4325    }
4326
4327    pub fn max_point(&self) -> Point {
4328        self.text_summary().lines
4329    }
4330
4331    pub fn max_row(&self) -> MultiBufferRow {
4332        MultiBufferRow(self.text_summary().lines.row)
4333    }
4334
4335    pub fn text_summary(&self) -> TextSummary {
4336        self.diff_transforms.summary().output
4337    }
4338
4339    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4340    where
4341        D: TextDimension,
4342        O: ToOffset,
4343    {
4344        let range = range.start.to_offset(self)..range.end.to_offset(self);
4345        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4346        cursor.seek(&range.start, Bias::Right, &());
4347
4348        let Some(first_transform) = cursor.item() else {
4349            return D::from_text_summary(&TextSummary::default());
4350        };
4351
4352        let diff_transform_start = cursor.start().0;
4353        let diff_transform_end = cursor.end(&()).0;
4354        let diff_start = range.start;
4355        let start_overshoot = diff_start - diff_transform_start;
4356        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4357
4358        let mut result = match first_transform {
4359            DiffTransform::BufferContent { .. } => {
4360                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4361                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4362                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4363            }
4364            DiffTransform::DeletedHunk {
4365                buffer_id,
4366                base_text_byte_range,
4367                has_trailing_newline,
4368                ..
4369            } => {
4370                let buffer_start = base_text_byte_range.start + start_overshoot;
4371                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4372                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4373                    panic!("{:?} is in non-existent deleted hunk", range.start)
4374                };
4375
4376                let include_trailing_newline =
4377                    *has_trailing_newline && range.end >= diff_transform_end;
4378                if include_trailing_newline {
4379                    buffer_end -= 1;
4380                }
4381
4382                let mut summary =
4383                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4384
4385                if include_trailing_newline {
4386                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4387                }
4388
4389                summary
4390            }
4391        };
4392        if range.end < diff_transform_end {
4393            return result;
4394        }
4395
4396        cursor.next(&());
4397        result.add_assign(&D::from_text_summary(&cursor.summary(
4398            &range.end,
4399            Bias::Right,
4400            &(),
4401        )));
4402
4403        let Some(last_transform) = cursor.item() else {
4404            return result;
4405        };
4406
4407        let overshoot = range.end - cursor.start().0;
4408        let suffix = match last_transform {
4409            DiffTransform::BufferContent { .. } => {
4410                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4411                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4412            }
4413            DiffTransform::DeletedHunk {
4414                base_text_byte_range,
4415                buffer_id,
4416                has_trailing_newline,
4417                ..
4418            } => {
4419                let buffer_end = base_text_byte_range.start + overshoot;
4420                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4421                    panic!("{:?} is in non-existent deleted hunk", range.end)
4422                };
4423
4424                let mut suffix = base_text
4425                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4426                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4427                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4428                }
4429                suffix
4430            }
4431        };
4432
4433        result.add_assign(&suffix);
4434        result
4435    }
4436
4437    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4438    where
4439        D: TextDimension,
4440    {
4441        // let mut range = range.start..range.end;
4442        let mut summary = D::zero(&());
4443        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4444        cursor.seek(&range.start, Bias::Right, &());
4445        if let Some(excerpt) = cursor.item() {
4446            let mut end_before_newline = cursor.end(&());
4447            if excerpt.has_trailing_newline {
4448                end_before_newline -= ExcerptOffset::new(1);
4449            }
4450
4451            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4452            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4453            let end_in_excerpt =
4454                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4455            summary.add_assign(
4456                &excerpt
4457                    .buffer
4458                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4459            );
4460
4461            if range.end > end_before_newline {
4462                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4463            }
4464
4465            cursor.next(&());
4466        }
4467
4468        if range.end > *cursor.start() {
4469            summary.add_assign(
4470                &cursor
4471                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4472                    .0,
4473            );
4474            if let Some(excerpt) = cursor.item() {
4475                range.end = cmp::max(*cursor.start(), range.end);
4476
4477                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4478                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4479                summary.add_assign(
4480                    &excerpt
4481                        .buffer
4482                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4483                );
4484            }
4485        }
4486
4487        summary
4488    }
4489
4490    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4491    where
4492        D: TextDimension + Ord + Sub<D, Output = D>,
4493    {
4494        self.summaries_for_anchors([anchor])[0]
4495    }
4496
4497    fn resolve_summary_for_anchor<D>(
4498        &self,
4499        anchor: &Anchor,
4500        excerpt_position: D,
4501        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4502    ) -> D
4503    where
4504        D: TextDimension + Ord + Sub<D, Output = D>,
4505    {
4506        loop {
4507            let transform_end_position = diff_transforms.end(&()).0 .0;
4508            let at_transform_end =
4509                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4510            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4511                diff_transforms.next(&());
4512                continue;
4513            }
4514
4515            let mut position = diff_transforms.start().1 .0;
4516            match diff_transforms.item() {
4517                Some(DiffTransform::DeletedHunk {
4518                    buffer_id,
4519                    base_text_byte_range,
4520                    ..
4521                }) => {
4522                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4523                        if let Some(base_text) =
4524                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4525                        {
4526                            if base_text.can_resolve(&diff_base_anchor) {
4527                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4528                                if base_text_offset >= base_text_byte_range.start
4529                                    && base_text_offset <= base_text_byte_range.end
4530                                {
4531                                    let position_in_hunk = base_text
4532                                        .text_summary_for_range::<D, _>(
4533                                            base_text_byte_range.start..base_text_offset,
4534                                        );
4535                                    position.add_assign(&position_in_hunk);
4536                                } else if at_transform_end {
4537                                    diff_transforms.next(&());
4538                                    continue;
4539                                }
4540                            }
4541                        }
4542                    }
4543                }
4544                _ => {
4545                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4546                        diff_transforms.next(&());
4547                        continue;
4548                    }
4549                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4550                    position.add_assign(&overshoot);
4551                }
4552            }
4553
4554            return position;
4555        }
4556    }
4557
4558    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4559        let mut cursor = self
4560            .excerpts
4561            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4562        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4563
4564        cursor.seek(&Some(locator), Bias::Left, &());
4565        if cursor.item().is_none() {
4566            cursor.next(&());
4567        }
4568
4569        let mut position = cursor.start().1;
4570        if let Some(excerpt) = cursor.item() {
4571            if excerpt.id == anchor.excerpt_id {
4572                let excerpt_buffer_start = excerpt
4573                    .buffer
4574                    .offset_for_anchor(&excerpt.range.context.start);
4575                let excerpt_buffer_end =
4576                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4577                let buffer_position = cmp::min(
4578                    excerpt_buffer_end,
4579                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4580                );
4581                if buffer_position > excerpt_buffer_start {
4582                    position.value += buffer_position - excerpt_buffer_start;
4583                }
4584            }
4585        }
4586        position
4587    }
4588
4589    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4590    where
4591        D: TextDimension + Ord + Sub<D, Output = D>,
4592        I: 'a + IntoIterator<Item = &'a Anchor>,
4593    {
4594        let mut anchors = anchors.into_iter().peekable();
4595        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4596        let mut diff_transforms_cursor = self
4597            .diff_transforms
4598            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4599        diff_transforms_cursor.next(&());
4600
4601        let mut summaries = Vec::new();
4602        while let Some(anchor) = anchors.peek() {
4603            let excerpt_id = anchor.excerpt_id;
4604            let excerpt_anchors = iter::from_fn(|| {
4605                let anchor = anchors.peek()?;
4606                if anchor.excerpt_id == excerpt_id {
4607                    Some(anchors.next().unwrap())
4608                } else {
4609                    None
4610                }
4611            });
4612
4613            let locator = self.excerpt_locator_for_id(excerpt_id);
4614            cursor.seek_forward(locator, Bias::Left, &());
4615            if cursor.item().is_none() {
4616                cursor.next(&());
4617            }
4618
4619            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4620            if let Some(excerpt) = cursor.item() {
4621                if excerpt.id != excerpt_id {
4622                    let position = self.resolve_summary_for_anchor(
4623                        &Anchor::min(),
4624                        excerpt_start_position,
4625                        &mut diff_transforms_cursor,
4626                    );
4627                    summaries.extend(excerpt_anchors.map(|_| position));
4628                    continue;
4629                }
4630                let excerpt_buffer_start =
4631                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4632                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4633                for (buffer_summary, anchor) in excerpt
4634                    .buffer
4635                    .summaries_for_anchors_with_payload::<D, _, _>(
4636                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4637                    )
4638                {
4639                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4640                    let mut position = excerpt_start_position;
4641                    if summary > excerpt_buffer_start {
4642                        position.add_assign(&(summary - excerpt_buffer_start));
4643                    }
4644
4645                    if position > diff_transforms_cursor.start().0 .0 {
4646                        diff_transforms_cursor.seek_forward(
4647                            &ExcerptDimension(position),
4648                            Bias::Left,
4649                            &(),
4650                        );
4651                    }
4652
4653                    summaries.push(self.resolve_summary_for_anchor(
4654                        anchor,
4655                        position,
4656                        &mut diff_transforms_cursor,
4657                    ));
4658                }
4659            } else {
4660                diff_transforms_cursor.seek_forward(
4661                    &ExcerptDimension(excerpt_start_position),
4662                    Bias::Left,
4663                    &(),
4664                );
4665                let position = self.resolve_summary_for_anchor(
4666                    &Anchor::max(),
4667                    excerpt_start_position,
4668                    &mut diff_transforms_cursor,
4669                );
4670                summaries.extend(excerpt_anchors.map(|_| position));
4671            }
4672        }
4673
4674        summaries
4675    }
4676
4677    pub fn dimensions_from_points<'a, D>(
4678        &'a self,
4679        points: impl 'a + IntoIterator<Item = Point>,
4680    ) -> impl 'a + Iterator<Item = D>
4681    where
4682        D: TextDimension + Sub<D, Output = D>,
4683    {
4684        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4685        cursor.seek(&DimensionPair {
4686            key: Point::default(),
4687            value: None,
4688        });
4689        let mut points = points.into_iter();
4690        iter::from_fn(move || {
4691            let point = points.next()?;
4692
4693            cursor.seek_forward(&DimensionPair {
4694                key: point,
4695                value: None,
4696            });
4697
4698            if let Some(region) = cursor.region() {
4699                let overshoot = point - region.range.start.key;
4700                let buffer_point = region.buffer_range.start.key + overshoot;
4701                let mut position = region.range.start.value.unwrap();
4702                position.add_assign(
4703                    &region
4704                        .buffer
4705                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4706                );
4707                return Some(position);
4708            } else {
4709                return Some(D::from_text_summary(&self.text_summary()));
4710            }
4711        })
4712    }
4713
4714    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4715    where
4716        I: 'a + IntoIterator<Item = &'a Anchor>,
4717    {
4718        let mut anchors = anchors.into_iter().enumerate().peekable();
4719        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4720        cursor.next(&());
4721
4722        let mut result = Vec::new();
4723
4724        while let Some((_, anchor)) = anchors.peek() {
4725            let old_excerpt_id = anchor.excerpt_id;
4726
4727            // Find the location where this anchor's excerpt should be.
4728            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4729            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4730
4731            if cursor.item().is_none() {
4732                cursor.next(&());
4733            }
4734
4735            let next_excerpt = cursor.item();
4736            let prev_excerpt = cursor.prev_item();
4737
4738            // Process all of the anchors for this excerpt.
4739            while let Some((_, anchor)) = anchors.peek() {
4740                if anchor.excerpt_id != old_excerpt_id {
4741                    break;
4742                }
4743                let (anchor_ix, anchor) = anchors.next().unwrap();
4744                let mut anchor = *anchor;
4745
4746                // Leave min and max anchors unchanged if invalid or
4747                // if the old excerpt still exists at this location
4748                let mut kept_position = next_excerpt
4749                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4750                    || old_excerpt_id == ExcerptId::max()
4751                    || old_excerpt_id == ExcerptId::min();
4752
4753                // If the old excerpt no longer exists at this location, then attempt to
4754                // find an equivalent position for this anchor in an adjacent excerpt.
4755                if !kept_position {
4756                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4757                        if excerpt.contains(&anchor) {
4758                            anchor.excerpt_id = excerpt.id;
4759                            kept_position = true;
4760                            break;
4761                        }
4762                    }
4763                }
4764
4765                // If there's no adjacent excerpt that contains the anchor's position,
4766                // then report that the anchor has lost its position.
4767                if !kept_position {
4768                    anchor = if let Some(excerpt) = next_excerpt {
4769                        let mut text_anchor = excerpt
4770                            .range
4771                            .context
4772                            .start
4773                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4774                        if text_anchor
4775                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4776                            .is_gt()
4777                        {
4778                            text_anchor = excerpt.range.context.end;
4779                        }
4780                        Anchor {
4781                            buffer_id: Some(excerpt.buffer_id),
4782                            excerpt_id: excerpt.id,
4783                            text_anchor,
4784                            diff_base_anchor: None,
4785                        }
4786                    } else if let Some(excerpt) = prev_excerpt {
4787                        let mut text_anchor = excerpt
4788                            .range
4789                            .context
4790                            .end
4791                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4792                        if text_anchor
4793                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4794                            .is_lt()
4795                        {
4796                            text_anchor = excerpt.range.context.start;
4797                        }
4798                        Anchor {
4799                            buffer_id: Some(excerpt.buffer_id),
4800                            excerpt_id: excerpt.id,
4801                            text_anchor,
4802                            diff_base_anchor: None,
4803                        }
4804                    } else if anchor.text_anchor.bias == Bias::Left {
4805                        Anchor::min()
4806                    } else {
4807                        Anchor::max()
4808                    };
4809                }
4810
4811                result.push((anchor_ix, anchor, kept_position));
4812            }
4813        }
4814        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4815        result
4816    }
4817
4818    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4819        self.anchor_at(position, Bias::Left)
4820    }
4821
4822    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4823        self.anchor_at(position, Bias::Right)
4824    }
4825
4826    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4827        let offset = position.to_offset(self);
4828
4829        // Find the given position in the diff transforms. Determine the corresponding
4830        // offset in the excerpts, and whether the position is within a deleted hunk.
4831        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4832        diff_transforms.seek(&offset, Bias::Right, &());
4833
4834        if offset == diff_transforms.start().0 && bias == Bias::Left {
4835            if let Some(prev_item) = diff_transforms.prev_item() {
4836                match prev_item {
4837                    DiffTransform::DeletedHunk { .. } => {
4838                        diff_transforms.prev(&());
4839                    }
4840                    _ => {}
4841                }
4842            }
4843        }
4844        let offset_in_transform = offset - diff_transforms.start().0;
4845        let mut excerpt_offset = diff_transforms.start().1;
4846        let mut diff_base_anchor = None;
4847        if let Some(DiffTransform::DeletedHunk {
4848            buffer_id,
4849            base_text_byte_range,
4850            has_trailing_newline,
4851            ..
4852        }) = diff_transforms.item()
4853        {
4854            let diff = self.diffs.get(buffer_id).expect("missing diff");
4855            if offset_in_transform > base_text_byte_range.len() {
4856                debug_assert!(*has_trailing_newline);
4857                bias = Bias::Right;
4858            } else {
4859                diff_base_anchor = Some(
4860                    diff.base_text()
4861                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4862                );
4863                bias = Bias::Left;
4864            }
4865        } else {
4866            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4867        };
4868
4869        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4870            return Anchor {
4871                buffer_id: Some(buffer_id),
4872                excerpt_id: *excerpt_id,
4873                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4874                diff_base_anchor,
4875            };
4876        }
4877
4878        let mut excerpts = self
4879            .excerpts
4880            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4881        excerpts.seek(&excerpt_offset, Bias::Right, &());
4882        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4883            excerpts.prev(&());
4884        }
4885        if let Some(excerpt) = excerpts.item() {
4886            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4887            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4888                overshoot -= 1;
4889                bias = Bias::Right;
4890            }
4891
4892            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4893            let text_anchor =
4894                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4895            Anchor {
4896                buffer_id: Some(excerpt.buffer_id),
4897                excerpt_id: excerpt.id,
4898                text_anchor,
4899                diff_base_anchor,
4900            }
4901        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4902            Anchor::min()
4903        } else {
4904            Anchor::max()
4905        }
4906    }
4907
4908    /// Returns an anchor for the given excerpt and text anchor,
4909    /// returns None if the excerpt_id is no longer valid.
4910    pub fn anchor_in_excerpt(
4911        &self,
4912        excerpt_id: ExcerptId,
4913        text_anchor: text::Anchor,
4914    ) -> Option<Anchor> {
4915        let locator = self.excerpt_locator_for_id(excerpt_id);
4916        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4917        cursor.seek(locator, Bias::Left, &());
4918        if let Some(excerpt) = cursor.item() {
4919            if excerpt.id == excerpt_id {
4920                let text_anchor = excerpt.clip_anchor(text_anchor);
4921                drop(cursor);
4922                return Some(Anchor {
4923                    buffer_id: Some(excerpt.buffer_id),
4924                    excerpt_id,
4925                    text_anchor,
4926                    diff_base_anchor: None,
4927                });
4928            }
4929        }
4930        None
4931    }
4932
4933    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4934        Some(self.excerpt(excerpt_id)?.range.context.clone())
4935    }
4936
4937    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4938        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4939            true
4940        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4941            excerpt.buffer.can_resolve(&anchor.text_anchor)
4942        } else {
4943            false
4944        }
4945    }
4946
4947    pub fn excerpts(
4948        &self,
4949    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4950        self.excerpts
4951            .iter()
4952            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4953    }
4954
4955    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4956        let excerpts = self.excerpts.cursor(&());
4957        let diff_transforms = self.diff_transforms.cursor(&());
4958        MultiBufferCursor {
4959            excerpts,
4960            diff_transforms,
4961            diffs: &self.diffs,
4962            cached_region: None,
4963        }
4964    }
4965
4966    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4967        let start_locator = self.excerpt_locator_for_id(id);
4968        let mut excerpts = self
4969            .excerpts
4970            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4971        excerpts.seek(&Some(start_locator), Bias::Left, &());
4972        excerpts.prev(&());
4973
4974        let mut diff_transforms = self
4975            .diff_transforms
4976            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
4977        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
4978        if diff_transforms.end(&()).1 < excerpts.start().1 {
4979            diff_transforms.next(&());
4980        }
4981
4982        let excerpt = excerpts.item()?;
4983        Some(MultiBufferExcerpt {
4984            excerpt,
4985            offset: diff_transforms.start().0 .0,
4986            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4987            excerpt_offset: excerpts.start().1.clone(),
4988            diff_transforms,
4989        })
4990    }
4991
4992    pub fn excerpt_boundaries_in_range<R, T>(
4993        &self,
4994        range: R,
4995    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4996    where
4997        R: RangeBounds<T>,
4998        T: ToOffset,
4999    {
5000        let start_offset;
5001        let start = match range.start_bound() {
5002            Bound::Included(start) => {
5003                start_offset = start.to_offset(self);
5004                Bound::Included(start_offset)
5005            }
5006            Bound::Excluded(_) => {
5007                panic!("not supported")
5008            }
5009            Bound::Unbounded => {
5010                start_offset = 0;
5011                Bound::Unbounded
5012            }
5013        };
5014        let end = match range.end_bound() {
5015            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5016            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5017            Bound::Unbounded => Bound::Unbounded,
5018        };
5019        let bounds = (start, end);
5020
5021        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5022        cursor.seek(&DimensionPair {
5023            key: start_offset,
5024            value: None,
5025        });
5026
5027        if cursor
5028            .region()
5029            .is_some_and(|region| bounds.contains(&region.range.start.key))
5030        {
5031            cursor.prev_excerpt();
5032        } else {
5033            cursor.seek_to_start_of_current_excerpt();
5034        }
5035        let mut prev_region = cursor.region();
5036
5037        cursor.next_excerpt();
5038
5039        let mut visited_end = false;
5040        iter::from_fn(move || loop {
5041            if self.singleton {
5042                return None;
5043            }
5044
5045            let next_region = cursor.region();
5046            cursor.next_excerpt();
5047
5048            let next_region_start = if let Some(region) = &next_region {
5049                if !bounds.contains(&region.range.start.key) {
5050                    prev_region = next_region;
5051                    continue;
5052                }
5053                region.range.start.value.unwrap()
5054            } else {
5055                if !bounds.contains(&self.len()) {
5056                    return None;
5057                }
5058                self.max_point()
5059            };
5060            let next_region_end = if let Some(region) = cursor.region() {
5061                region.range.start.value.unwrap()
5062            } else {
5063                self.max_point()
5064            };
5065
5066            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5067                id: region.excerpt.id,
5068                buffer: region.excerpt.buffer.clone(),
5069                buffer_id: region.excerpt.buffer_id,
5070                range: region.excerpt.range.clone(),
5071                end_row: MultiBufferRow(next_region_start.row),
5072            });
5073
5074            let next = next_region.as_ref().map(|region| ExcerptInfo {
5075                id: region.excerpt.id,
5076                buffer: region.excerpt.buffer.clone(),
5077                buffer_id: region.excerpt.buffer_id,
5078                range: region.excerpt.range.clone(),
5079                end_row: if region.excerpt.has_trailing_newline {
5080                    MultiBufferRow(next_region_end.row - 1)
5081                } else {
5082                    MultiBufferRow(next_region_end.row)
5083                },
5084            });
5085
5086            if next.is_none() {
5087                if visited_end {
5088                    return None;
5089                } else {
5090                    visited_end = true;
5091                }
5092            }
5093
5094            let row = MultiBufferRow(next_region_start.row);
5095
5096            prev_region = next_region;
5097
5098            return Some(ExcerptBoundary { row, prev, next });
5099        })
5100    }
5101
5102    pub fn edit_count(&self) -> usize {
5103        self.edit_count
5104    }
5105
5106    pub fn non_text_state_update_count(&self) -> usize {
5107        self.non_text_state_update_count
5108    }
5109
5110    /// Returns the smallest enclosing bracket ranges containing the given range or
5111    /// None if no brackets contain range or the range is not contained in a single
5112    /// excerpt
5113    ///
5114    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5115    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5116        &self,
5117        range: Range<T>,
5118        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5119    ) -> Option<(Range<usize>, Range<usize>)> {
5120        let range = range.start.to_offset(self)..range.end.to_offset(self);
5121        let mut excerpt = self.excerpt_containing(range.clone())?;
5122        let buffer = excerpt.buffer();
5123        let excerpt_buffer_range = excerpt.buffer_range();
5124
5125        // Filter to ranges contained in the excerpt
5126        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5127            excerpt_buffer_range.contains(&open.start)
5128                && excerpt_buffer_range.contains(&close.end)
5129                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5130        };
5131
5132        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5133            excerpt.map_range_to_buffer(range),
5134            Some(&range_filter),
5135        )?;
5136
5137        Some((
5138            excerpt.map_range_from_buffer(open),
5139            excerpt.map_range_from_buffer(close),
5140        ))
5141    }
5142
5143    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5144    /// not contained in a single excerpt
5145    pub fn enclosing_bracket_ranges<T: ToOffset>(
5146        &self,
5147        range: Range<T>,
5148    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5149        let range = range.start.to_offset(self)..range.end.to_offset(self);
5150        let mut excerpt = self.excerpt_containing(range.clone())?;
5151
5152        Some(
5153            excerpt
5154                .buffer()
5155                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5156                .filter_map(move |pair| {
5157                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5158                        Some((
5159                            excerpt.map_range_from_buffer(pair.open_range),
5160                            excerpt.map_range_from_buffer(pair.close_range),
5161                        ))
5162                    } else {
5163                        None
5164                    }
5165                }),
5166        )
5167    }
5168
5169    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5170    /// not contained in a single excerpt
5171    pub fn text_object_ranges<T: ToOffset>(
5172        &self,
5173        range: Range<T>,
5174        options: TreeSitterOptions,
5175    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5176        let range = range.start.to_offset(self)..range.end.to_offset(self);
5177        self.excerpt_containing(range.clone())
5178            .map(|mut excerpt| {
5179                excerpt
5180                    .buffer()
5181                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5182                    .filter_map(move |(range, text_object)| {
5183                        if excerpt.contains_buffer_range(range.clone()) {
5184                            Some((excerpt.map_range_from_buffer(range), text_object))
5185                        } else {
5186                            None
5187                        }
5188                    })
5189            })
5190            .into_iter()
5191            .flatten()
5192    }
5193
5194    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5195    /// not contained in a single excerpt
5196    pub fn bracket_ranges<T: ToOffset>(
5197        &self,
5198        range: Range<T>,
5199    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5200        let range = range.start.to_offset(self)..range.end.to_offset(self);
5201        let mut excerpt = self.excerpt_containing(range.clone())?;
5202
5203        Some(
5204            excerpt
5205                .buffer()
5206                .bracket_ranges(excerpt.map_range_to_buffer(range))
5207                .filter_map(move |pair| {
5208                    let buffer_range = pair.open_range.start..pair.close_range.end;
5209                    if excerpt.contains_buffer_range(buffer_range) {
5210                        Some((
5211                            excerpt.map_range_from_buffer(pair.open_range),
5212                            excerpt.map_range_from_buffer(pair.close_range),
5213                        ))
5214                    } else {
5215                        None
5216                    }
5217                }),
5218        )
5219    }
5220
5221    pub fn redacted_ranges<'a, T: ToOffset>(
5222        &'a self,
5223        range: Range<T>,
5224        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5225    ) -> impl Iterator<Item = Range<usize>> + 'a {
5226        let range = range.start.to_offset(self)..range.end.to_offset(self);
5227        self.lift_buffer_metadata(range, move |buffer, range| {
5228            if redaction_enabled(buffer.file()) {
5229                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5230            } else {
5231                None
5232            }
5233        })
5234        .map(|(range, _, _)| range)
5235    }
5236
5237    pub fn runnable_ranges(
5238        &self,
5239        range: Range<Anchor>,
5240    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5241        let range = range.start.to_offset(self)..range.end.to_offset(self);
5242        self.lift_buffer_metadata(range, move |buffer, range| {
5243            Some(
5244                buffer
5245                    .runnable_ranges(range.clone())
5246                    .filter(move |runnable| {
5247                        runnable.run_range.start >= range.start
5248                            && runnable.run_range.end < range.end
5249                    })
5250                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5251            )
5252        })
5253        .map(|(run_range, runnable, _)| language::RunnableRange {
5254            run_range,
5255            ..runnable
5256        })
5257    }
5258
5259    pub fn line_indents(
5260        &self,
5261        start_row: MultiBufferRow,
5262        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5263    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5264        let max_point = self.max_point();
5265        let mut cursor = self.cursor::<Point>();
5266        cursor.seek(&Point::new(start_row.0, 0));
5267        iter::from_fn(move || {
5268            let mut region = cursor.region()?;
5269            while !buffer_filter(&region.excerpt.buffer) {
5270                cursor.next();
5271                region = cursor.region()?;
5272            }
5273            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5274            let buffer_start_row =
5275                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5276
5277            let buffer_end_row = if region.is_main_buffer
5278                && (region.has_trailing_newline || region.range.end == max_point)
5279            {
5280                region.buffer_range.end.row
5281            } else {
5282                region.buffer_range.end.row.saturating_sub(1)
5283            };
5284
5285            let line_indents = region
5286                .buffer
5287                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5288            cursor.next();
5289            return Some(line_indents.map(move |(buffer_row, indent)| {
5290                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5291                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5292            }));
5293        })
5294        .flatten()
5295    }
5296
5297    pub fn reversed_line_indents(
5298        &self,
5299        end_row: MultiBufferRow,
5300        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5301    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5302        let max_point = self.max_point();
5303        let mut cursor = self.cursor::<Point>();
5304        cursor.seek(&Point::new(end_row.0, 0));
5305        iter::from_fn(move || {
5306            let mut region = cursor.region()?;
5307            while !buffer_filter(&region.excerpt.buffer) {
5308                cursor.prev();
5309                region = cursor.region()?;
5310            }
5311
5312            let buffer_start_row = region.buffer_range.start.row;
5313            let buffer_end_row = if region.is_main_buffer
5314                && (region.has_trailing_newline || region.range.end == max_point)
5315            {
5316                region.buffer_range.end.row + 1
5317            } else {
5318                region.buffer_range.end.row
5319            };
5320
5321            let overshoot = end_row.0 - region.range.start.row;
5322            let buffer_end_row =
5323                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5324
5325            let line_indents = region
5326                .buffer
5327                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5328            cursor.prev();
5329            return Some(line_indents.map(move |(buffer_row, indent)| {
5330                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5331                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5332            }));
5333        })
5334        .flatten()
5335    }
5336
5337    pub async fn enclosing_indent(
5338        &self,
5339        mut target_row: MultiBufferRow,
5340    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5341        let max_row = MultiBufferRow(self.max_point().row);
5342        if target_row >= max_row {
5343            return None;
5344        }
5345
5346        let mut target_indent = self.line_indent_for_row(target_row);
5347
5348        // If the current row is at the start of an indented block, we want to return this
5349        // block as the enclosing indent.
5350        if !target_indent.is_line_empty() && target_row < max_row {
5351            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5352            if !next_line_indent.is_line_empty()
5353                && target_indent.raw_len() < next_line_indent.raw_len()
5354            {
5355                target_indent = next_line_indent;
5356                target_row.0 += 1;
5357            }
5358        }
5359
5360        const SEARCH_ROW_LIMIT: u32 = 25000;
5361        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5362        const YIELD_INTERVAL: u32 = 100;
5363
5364        let mut accessed_row_counter = 0;
5365
5366        // If there is a blank line at the current row, search for the next non indented lines
5367        if target_indent.is_line_empty() {
5368            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5369            let end =
5370                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5371
5372            let mut non_empty_line_above = None;
5373            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5374                if row < start {
5375                    break;
5376                }
5377                accessed_row_counter += 1;
5378                if accessed_row_counter == YIELD_INTERVAL {
5379                    accessed_row_counter = 0;
5380                    yield_now().await;
5381                }
5382                if !indent.is_line_empty() {
5383                    non_empty_line_above = Some((row, indent));
5384                    break;
5385                }
5386            }
5387
5388            let mut non_empty_line_below = None;
5389            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5390                if row > end {
5391                    break;
5392                }
5393                accessed_row_counter += 1;
5394                if accessed_row_counter == YIELD_INTERVAL {
5395                    accessed_row_counter = 0;
5396                    yield_now().await;
5397                }
5398                if !indent.is_line_empty() {
5399                    non_empty_line_below = Some((row, indent));
5400                    break;
5401                }
5402            }
5403
5404            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5405                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5406                    if above_indent.raw_len() >= below_indent.raw_len() {
5407                        (above_row, above_indent)
5408                    } else {
5409                        (below_row, below_indent)
5410                    }
5411                }
5412                (Some(above), None) => above,
5413                (None, Some(below)) => below,
5414                _ => return None,
5415            };
5416
5417            target_indent = indent;
5418            target_row = row;
5419        }
5420
5421        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5422        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5423
5424        let mut start_indent = None;
5425        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5426            if row < start {
5427                break;
5428            }
5429            accessed_row_counter += 1;
5430            if accessed_row_counter == YIELD_INTERVAL {
5431                accessed_row_counter = 0;
5432                yield_now().await;
5433            }
5434            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5435                start_indent = Some((row, indent));
5436                break;
5437            }
5438        }
5439        let (start_row, start_indent_size) = start_indent?;
5440
5441        let mut end_indent = (end, None);
5442        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5443            if row > end {
5444                break;
5445            }
5446            accessed_row_counter += 1;
5447            if accessed_row_counter == YIELD_INTERVAL {
5448                accessed_row_counter = 0;
5449                yield_now().await;
5450            }
5451            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5452                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5453                break;
5454            }
5455        }
5456        let (end_row, end_indent_size) = end_indent;
5457
5458        let indent = if let Some(end_indent_size) = end_indent_size {
5459            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5460                start_indent_size
5461            } else {
5462                end_indent_size
5463            }
5464        } else {
5465            start_indent_size
5466        };
5467
5468        Some((start_row..end_row, indent))
5469    }
5470
5471    pub fn indent_guides_in_range<T: ToPoint>(
5472        &self,
5473        range: Range<T>,
5474        ignore_disabled_for_language: bool,
5475        cx: &App,
5476    ) -> impl Iterator<Item = IndentGuide> {
5477        let range = range.start.to_point(self)..range.end.to_point(self);
5478        let start_row = MultiBufferRow(range.start.row);
5479        let end_row = MultiBufferRow(range.end.row);
5480
5481        let mut row_indents = self.line_indents(start_row, |buffer| {
5482            let settings =
5483                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5484            settings.indent_guides.enabled || ignore_disabled_for_language
5485        });
5486
5487        let mut result = Vec::new();
5488        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5489
5490        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5491            if first_row > end_row {
5492                break;
5493            }
5494            let current_depth = indent_stack.len() as u32;
5495
5496            let settings =
5497                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5498            let tab_size = settings.tab_size.get() as u32;
5499
5500            // When encountering empty, continue until found useful line indent
5501            // then add to the indent stack with the depth found
5502            let mut found_indent = false;
5503            let mut last_row = first_row;
5504            if line_indent.is_line_empty() {
5505                while !found_indent {
5506                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5507                        break;
5508                    };
5509                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5510                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5511                        break;
5512                    }
5513
5514                    if new_line_indent.is_line_empty() {
5515                        continue;
5516                    }
5517                    last_row = target_row.min(end_row);
5518                    line_indent = new_line_indent;
5519                    found_indent = true;
5520                    break;
5521                }
5522            } else {
5523                found_indent = true
5524            }
5525
5526            let depth = if found_indent {
5527                line_indent.len(tab_size) / tab_size
5528                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5529            } else {
5530                current_depth
5531            };
5532
5533            match depth.cmp(&current_depth) {
5534                cmp::Ordering::Less => {
5535                    for _ in 0..(current_depth - depth) {
5536                        let mut indent = indent_stack.pop().unwrap();
5537                        if last_row != first_row {
5538                            // In this case, we landed on an empty row, had to seek forward,
5539                            // and discovered that the indent we where on is ending.
5540                            // This means that the last display row must
5541                            // be on line that ends this indent range, so we
5542                            // should display the range up to the first non-empty line
5543                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5544                        }
5545
5546                        result.push(indent)
5547                    }
5548                }
5549                cmp::Ordering::Greater => {
5550                    for next_depth in current_depth..depth {
5551                        indent_stack.push(IndentGuide {
5552                            buffer_id: buffer.remote_id(),
5553                            start_row: first_row,
5554                            end_row: last_row,
5555                            depth: next_depth,
5556                            tab_size,
5557                            settings: settings.indent_guides,
5558                        });
5559                    }
5560                }
5561                _ => {}
5562            }
5563
5564            for indent in indent_stack.iter_mut() {
5565                indent.end_row = last_row;
5566            }
5567        }
5568
5569        result.extend(indent_stack);
5570        result.into_iter()
5571    }
5572
5573    pub fn trailing_excerpt_update_count(&self) -> usize {
5574        self.trailing_excerpt_update_count
5575    }
5576
5577    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5578        self.point_to_buffer_offset(point)
5579            .and_then(|(buffer, _)| buffer.file())
5580    }
5581
5582    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5583        self.point_to_buffer_offset(point)
5584            .and_then(|(buffer, offset)| buffer.language_at(offset))
5585    }
5586
5587    pub fn settings_at<'a, T: ToOffset>(
5588        &'a self,
5589        point: T,
5590        cx: &'a App,
5591    ) -> Cow<'a, LanguageSettings> {
5592        let mut language = None;
5593        let mut file = None;
5594        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5595            language = buffer.language_at(offset);
5596            file = buffer.file();
5597        }
5598        language_settings(language.map(|l| l.name()), file, cx)
5599    }
5600
5601    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5602        self.point_to_buffer_offset(point)
5603            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5604    }
5605
5606    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5607        self.point_to_buffer_offset(point)
5608            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5609            .unwrap_or_default()
5610    }
5611
5612    pub fn language_indent_size_at<T: ToOffset>(
5613        &self,
5614        position: T,
5615        cx: &App,
5616    ) -> Option<IndentSize> {
5617        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5618        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5619    }
5620
5621    pub fn is_dirty(&self) -> bool {
5622        self.is_dirty
5623    }
5624
5625    pub fn has_deleted_file(&self) -> bool {
5626        self.has_deleted_file
5627    }
5628
5629    pub fn has_conflict(&self) -> bool {
5630        self.has_conflict
5631    }
5632
5633    pub fn has_diagnostics(&self) -> bool {
5634        self.excerpts
5635            .iter()
5636            .any(|excerpt| excerpt.buffer.has_diagnostics())
5637    }
5638
5639    pub fn diagnostic_group(
5640        &self,
5641        buffer_id: BufferId,
5642        group_id: usize,
5643    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5644        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5645            if buffer.remote_id() != buffer_id {
5646                return None;
5647            };
5648            Some(
5649                buffer
5650                    .diagnostic_group(group_id)
5651                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5652            )
5653        })
5654        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5655    }
5656
5657    pub fn diagnostics_in_range<'a, T>(
5658        &'a self,
5659        range: Range<T>,
5660    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5661    where
5662        T: 'a
5663            + text::ToOffset
5664            + text::FromAnchor
5665            + TextDimension
5666            + Ord
5667            + Sub<T, Output = T>
5668            + fmt::Debug,
5669    {
5670        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5671            Some(
5672                buffer
5673                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5674                    .map(|entry| (entry.range, entry.diagnostic)),
5675            )
5676        })
5677        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5678    }
5679
5680    pub fn syntax_ancestor<T: ToOffset>(
5681        &self,
5682        range: Range<T>,
5683    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5684        let range = range.start.to_offset(self)..range.end.to_offset(self);
5685        let mut excerpt = self.excerpt_containing(range.clone())?;
5686        let node = excerpt
5687            .buffer()
5688            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5689        let node_range = node.byte_range();
5690        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5691            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5692        } else {
5693            MultiOrSingleBufferOffsetRange::Single(node_range)
5694        };
5695        Some((node, range))
5696    }
5697
5698    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5699        let (excerpt_id, _, buffer) = self.as_singleton()?;
5700        let outline = buffer.outline(theme)?;
5701        Some(Outline::new(
5702            outline
5703                .items
5704                .into_iter()
5705                .flat_map(|item| {
5706                    Some(OutlineItem {
5707                        depth: item.depth,
5708                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5709                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5710                        text: item.text,
5711                        highlight_ranges: item.highlight_ranges,
5712                        name_ranges: item.name_ranges,
5713                        body_range: item.body_range.and_then(|body_range| {
5714                            Some(
5715                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5716                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5717                            )
5718                        }),
5719                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5720                            Some(
5721                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5722                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5723                            )
5724                        }),
5725                    })
5726                })
5727                .collect(),
5728        ))
5729    }
5730
5731    pub fn symbols_containing<T: ToOffset>(
5732        &self,
5733        offset: T,
5734        theme: Option<&SyntaxTheme>,
5735    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5736        let anchor = self.anchor_before(offset);
5737        let excerpt_id = anchor.excerpt_id;
5738        let excerpt = self.excerpt(excerpt_id)?;
5739        Some((
5740            excerpt.buffer_id,
5741            excerpt
5742                .buffer
5743                .symbols_containing(anchor.text_anchor, theme)
5744                .into_iter()
5745                .flatten()
5746                .flat_map(|item| {
5747                    Some(OutlineItem {
5748                        depth: item.depth,
5749                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5750                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5751                        text: item.text,
5752                        highlight_ranges: item.highlight_ranges,
5753                        name_ranges: item.name_ranges,
5754                        body_range: item.body_range.and_then(|body_range| {
5755                            Some(
5756                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5757                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5758                            )
5759                        }),
5760                        annotation_range: item.annotation_range.and_then(|body_range| {
5761                            Some(
5762                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5763                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5764                            )
5765                        }),
5766                    })
5767                })
5768                .collect(),
5769        ))
5770    }
5771
5772    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5773        if id == ExcerptId::min() {
5774            Locator::min_ref()
5775        } else if id == ExcerptId::max() {
5776            Locator::max_ref()
5777        } else {
5778            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5779            cursor.seek(&id, Bias::Left, &());
5780            if let Some(entry) = cursor.item() {
5781                if entry.id == id {
5782                    return &entry.locator;
5783                }
5784            }
5785            panic!("invalid excerpt id {:?}", id)
5786        }
5787    }
5788
5789    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5790    fn excerpt_locators_for_ids(
5791        &self,
5792        ids: impl IntoIterator<Item = ExcerptId>,
5793    ) -> SmallVec<[Locator; 1]> {
5794        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5795        sorted_ids.sort_unstable();
5796        let mut locators = SmallVec::new();
5797
5798        while sorted_ids.last() == Some(&ExcerptId::max()) {
5799            sorted_ids.pop();
5800            if let Some(mapping) = self.excerpt_ids.last() {
5801                locators.push(mapping.locator.clone());
5802            }
5803        }
5804
5805        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5806        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5807            sorted_ids.next();
5808            if let Some(mapping) = self.excerpt_ids.first() {
5809                locators.push(mapping.locator.clone());
5810            }
5811        }
5812
5813        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5814        for id in sorted_ids {
5815            if cursor.seek_forward(&id, Bias::Left, &()) {
5816                locators.push(cursor.item().unwrap().locator.clone());
5817            } else {
5818                panic!("invalid excerpt id {:?}", id);
5819            }
5820        }
5821
5822        locators.sort_unstable();
5823        locators
5824    }
5825
5826    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5827        Some(self.excerpt(excerpt_id)?.buffer_id)
5828    }
5829
5830    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5831        Some(&self.excerpt(excerpt_id)?.buffer)
5832    }
5833
5834    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5835        let mut cursor = self
5836            .excerpts
5837            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5838        let locator = self.excerpt_locator_for_id(excerpt_id);
5839        if cursor.seek(&Some(locator), Bias::Left, &()) {
5840            let start = cursor.start().1.clone();
5841            let end = cursor.end(&()).1;
5842            let mut diff_transforms = self
5843                .diff_transforms
5844                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5845            diff_transforms.seek(&start, Bias::Left, &());
5846            let overshoot = start.0 - diff_transforms.start().0 .0;
5847            let start = diff_transforms.start().1 .0 + overshoot;
5848            diff_transforms.seek(&end, Bias::Right, &());
5849            let overshoot = end.0 - diff_transforms.start().0 .0;
5850            let end = diff_transforms.start().1 .0 + overshoot;
5851            Some(start..end)
5852        } else {
5853            None
5854        }
5855    }
5856
5857    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5858        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5859        let locator = self.excerpt_locator_for_id(excerpt_id);
5860        if cursor.seek(&Some(locator), Bias::Left, &()) {
5861            if let Some(excerpt) = cursor.item() {
5862                return Some(excerpt.range.context.clone());
5863            }
5864        }
5865        None
5866    }
5867
5868    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5869        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5870        let locator = self.excerpt_locator_for_id(excerpt_id);
5871        cursor.seek(&Some(locator), Bias::Left, &());
5872        if let Some(excerpt) = cursor.item() {
5873            if excerpt.id == excerpt_id {
5874                return Some(excerpt);
5875            }
5876        }
5877        None
5878    }
5879
5880    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5881    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5882        let range = range.start.to_offset(self)..range.end.to_offset(self);
5883        let mut cursor = self.cursor::<usize>();
5884        cursor.seek(&range.start);
5885
5886        let start_excerpt = cursor.excerpt()?;
5887        if range.end != range.start {
5888            cursor.seek_forward(&range.end);
5889            if cursor.excerpt()?.id != start_excerpt.id {
5890                return None;
5891            }
5892        }
5893
5894        cursor.seek_to_start_of_current_excerpt();
5895        let region = cursor.region()?;
5896        let offset = region.range.start;
5897        let buffer_offset = region.buffer_range.start;
5898        let excerpt_offset = cursor.excerpts.start().clone();
5899        Some(MultiBufferExcerpt {
5900            diff_transforms: cursor.diff_transforms,
5901            excerpt: start_excerpt,
5902            offset,
5903            buffer_offset,
5904            excerpt_offset,
5905        })
5906    }
5907
5908    pub fn selections_in_range<'a>(
5909        &'a self,
5910        range: &'a Range<Anchor>,
5911        include_local: bool,
5912    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5913        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5914        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5915        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5916        cursor.seek(start_locator, Bias::Left, &());
5917        cursor
5918            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5919            .flat_map(move |excerpt| {
5920                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5921                if excerpt.id == range.start.excerpt_id {
5922                    query_range.start = range.start.text_anchor;
5923                }
5924                if excerpt.id == range.end.excerpt_id {
5925                    query_range.end = range.end.text_anchor;
5926                }
5927
5928                excerpt
5929                    .buffer
5930                    .selections_in_range(query_range, include_local)
5931                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5932                        selections.map(move |selection| {
5933                            let mut start = Anchor {
5934                                buffer_id: Some(excerpt.buffer_id),
5935                                excerpt_id: excerpt.id,
5936                                text_anchor: selection.start,
5937                                diff_base_anchor: None,
5938                            };
5939                            let mut end = Anchor {
5940                                buffer_id: Some(excerpt.buffer_id),
5941                                excerpt_id: excerpt.id,
5942                                text_anchor: selection.end,
5943                                diff_base_anchor: None,
5944                            };
5945                            if range.start.cmp(&start, self).is_gt() {
5946                                start = range.start;
5947                            }
5948                            if range.end.cmp(&end, self).is_lt() {
5949                                end = range.end;
5950                            }
5951
5952                            (
5953                                replica_id,
5954                                line_mode,
5955                                cursor_shape,
5956                                Selection {
5957                                    id: selection.id,
5958                                    start,
5959                                    end,
5960                                    reversed: selection.reversed,
5961                                    goal: selection.goal,
5962                                },
5963                            )
5964                        })
5965                    })
5966            })
5967    }
5968
5969    pub fn show_headers(&self) -> bool {
5970        self.show_headers
5971    }
5972
5973    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5974        self.diffs.get(&buffer_id)
5975    }
5976}
5977
5978#[cfg(any(test, feature = "test-support"))]
5979impl MultiBufferSnapshot {
5980    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5981        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
5982        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
5983        start..end
5984    }
5985
5986    #[cfg(any(test, feature = "test-support"))]
5987    fn check_invariants(&self) {
5988        let excerpts = self.excerpts.items(&());
5989        let excerpt_ids = self.excerpt_ids.items(&());
5990
5991        for (ix, excerpt) in excerpts.iter().enumerate() {
5992            if ix == 0 {
5993                if excerpt.locator <= Locator::min() {
5994                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5995                }
5996            } else if excerpt.locator <= excerpts[ix - 1].locator {
5997                panic!("excerpts are out-of-order: {:?}", excerpts);
5998            }
5999        }
6000
6001        for (ix, entry) in excerpt_ids.iter().enumerate() {
6002            if ix == 0 {
6003                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6004                    panic!("invalid first excerpt id {:?}", entry.id);
6005                }
6006            } else if entry.id <= excerpt_ids[ix - 1].id {
6007                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6008            }
6009        }
6010
6011        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6012            panic!(
6013                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6014                self.excerpts.summary().text.len,
6015                self.diff_transforms.summary().input,
6016                self.diff_transforms.items(&()),
6017            );
6018        }
6019
6020        let mut prev_transform: Option<&DiffTransform> = None;
6021        for item in self.diff_transforms.iter() {
6022            if let DiffTransform::BufferContent {
6023                summary,
6024                inserted_hunk_info,
6025            } = item
6026            {
6027                if let Some(DiffTransform::BufferContent {
6028                    inserted_hunk_info: prev_inserted_hunk_info,
6029                    ..
6030                }) = prev_transform
6031                {
6032                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6033                        panic!(
6034                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6035                            self.diff_transforms.items(&()));
6036                    }
6037                }
6038                if summary.len == 0 && !self.is_empty() {
6039                    panic!("empty buffer content transform");
6040                }
6041            }
6042            prev_transform = Some(item);
6043        }
6044    }
6045}
6046
6047impl<'a, D> MultiBufferCursor<'a, D>
6048where
6049    D: TextDimension + Ord + Sub<D, Output = D>,
6050{
6051    fn seek(&mut self, position: &D) {
6052        self.cached_region.take();
6053        self.diff_transforms
6054            .seek(&OutputDimension(*position), Bias::Right, &());
6055        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6056            self.diff_transforms.prev(&());
6057        }
6058
6059        let mut excerpt_position = self.diff_transforms.start().1 .0;
6060        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6061            let overshoot = *position - self.diff_transforms.start().0 .0;
6062            excerpt_position.add_assign(&overshoot);
6063        }
6064
6065        self.excerpts
6066            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6067        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6068            self.excerpts.prev(&());
6069        }
6070    }
6071
6072    fn seek_forward(&mut self, position: &D) {
6073        self.cached_region.take();
6074        self.diff_transforms
6075            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6076        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6077            self.diff_transforms.prev(&());
6078        }
6079
6080        let overshoot = *position - self.diff_transforms.start().0 .0;
6081        let mut excerpt_position = self.diff_transforms.start().1 .0;
6082        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6083            excerpt_position.add_assign(&overshoot);
6084        }
6085
6086        self.excerpts
6087            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6088        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6089            self.excerpts.prev(&());
6090        }
6091    }
6092
6093    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
6094        self.cached_region.take();
6095        if let Some(excerpt) = self.excerpts.item() {
6096            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
6097            let position_in_excerpt = *position - excerpt_start;
6098            let mut excerpt_position = self.excerpts.start().0;
6099            excerpt_position.add_assign(&position_in_excerpt);
6100            self.diff_transforms
6101                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
6102            if self.diff_transforms.item().is_none() {
6103                self.diff_transforms.next(&());
6104            }
6105        }
6106    }
6107
6108    fn next_excerpt(&mut self) {
6109        self.excerpts.next(&());
6110        self.seek_to_start_of_current_excerpt();
6111    }
6112
6113    fn prev_excerpt(&mut self) {
6114        self.excerpts.prev(&());
6115        self.seek_to_start_of_current_excerpt();
6116    }
6117
6118    fn seek_to_start_of_current_excerpt(&mut self) {
6119        self.cached_region.take();
6120        self.diff_transforms
6121            .seek(self.excerpts.start(), Bias::Left, &());
6122        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6123            && self.diff_transforms.start().1 < *self.excerpts.start()
6124            && self.diff_transforms.next_item().is_some()
6125        {
6126            self.diff_transforms.next(&());
6127        }
6128    }
6129
6130    fn next(&mut self) {
6131        self.cached_region.take();
6132        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6133            cmp::Ordering::Less => self.diff_transforms.next(&()),
6134            cmp::Ordering::Greater => self.excerpts.next(&()),
6135            cmp::Ordering::Equal => {
6136                self.diff_transforms.next(&());
6137                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6138                    || self.diff_transforms.item().is_none()
6139                {
6140                    self.excerpts.next(&());
6141                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6142                    self.diff_transforms.item()
6143                {
6144                    if self
6145                        .excerpts
6146                        .item()
6147                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6148                    {
6149                        self.excerpts.next(&());
6150                    }
6151                }
6152            }
6153        }
6154    }
6155
6156    fn prev(&mut self) {
6157        self.cached_region.take();
6158        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6159            cmp::Ordering::Less => self.excerpts.prev(&()),
6160            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6161            cmp::Ordering::Equal => {
6162                self.diff_transforms.prev(&());
6163                if self.diff_transforms.start().1 < *self.excerpts.start()
6164                    || self.diff_transforms.item().is_none()
6165                {
6166                    self.excerpts.prev(&());
6167                }
6168            }
6169        }
6170    }
6171
6172    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6173        if self.cached_region.is_none() {
6174            self.cached_region = self.build_region();
6175        }
6176        self.cached_region.clone()
6177    }
6178
6179    fn is_at_end_of_excerpt(&mut self) -> bool {
6180        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6181            return false;
6182        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6183            || self.diff_transforms.item().is_none()
6184        {
6185            return true;
6186        }
6187
6188        let next_transform = self.diff_transforms.next_item();
6189        next_transform.map_or(true, |next_transform| match next_transform {
6190            DiffTransform::BufferContent { .. } => true,
6191            DiffTransform::DeletedHunk { hunk_info, .. } => self
6192                .excerpts
6193                .item()
6194                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6195        })
6196    }
6197
6198    fn main_buffer_position(&self) -> Option<D> {
6199        let excerpt = self.excerpts.item()?;
6200        let buffer = &excerpt.buffer;
6201        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6202        let mut buffer_start = buffer_context_start;
6203        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6204        buffer_start.add_assign(&overshoot);
6205        Some(buffer_start)
6206    }
6207
6208    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6209        let excerpt = self.excerpts.item()?;
6210        match self.diff_transforms.item()? {
6211            DiffTransform::DeletedHunk {
6212                buffer_id,
6213                base_text_byte_range,
6214                has_trailing_newline,
6215                hunk_info,
6216                ..
6217            } => {
6218                let diff = self.diffs.get(&buffer_id)?;
6219                let buffer = diff.base_text();
6220                let mut rope_cursor = buffer.as_rope().cursor(0);
6221                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6222                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6223                let mut buffer_end = buffer_start;
6224                buffer_end.add_assign(&buffer_range_len);
6225                let start = self.diff_transforms.start().0 .0;
6226                let end = self.diff_transforms.end(&()).0 .0;
6227                return Some(MultiBufferRegion {
6228                    buffer,
6229                    excerpt,
6230                    has_trailing_newline: *has_trailing_newline,
6231                    is_main_buffer: false,
6232                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6233                        hunk_info.hunk_secondary_status,
6234                    )),
6235                    buffer_range: buffer_start..buffer_end,
6236                    range: start..end,
6237                });
6238            }
6239            DiffTransform::BufferContent {
6240                inserted_hunk_info, ..
6241            } => {
6242                let buffer = &excerpt.buffer;
6243                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6244
6245                let mut start = self.diff_transforms.start().0 .0;
6246                let mut buffer_start = buffer_context_start;
6247                if self.diff_transforms.start().1 < *self.excerpts.start() {
6248                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6249                    start.add_assign(&overshoot);
6250                } else {
6251                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6252                    buffer_start.add_assign(&overshoot);
6253                }
6254
6255                let mut end;
6256                let mut buffer_end;
6257                let has_trailing_newline;
6258                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6259                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6260                    end = self.diff_transforms.end(&()).0 .0;
6261                    buffer_end = buffer_context_start;
6262                    buffer_end.add_assign(&overshoot);
6263                    has_trailing_newline = false;
6264                } else {
6265                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6266                    end = self.diff_transforms.start().0 .0;
6267                    end.add_assign(&overshoot);
6268                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6269                    has_trailing_newline = excerpt.has_trailing_newline;
6270                };
6271
6272                Some(MultiBufferRegion {
6273                    buffer,
6274                    excerpt,
6275                    has_trailing_newline,
6276                    is_main_buffer: true,
6277                    diff_hunk_status: inserted_hunk_info
6278                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6279                    buffer_range: buffer_start..buffer_end,
6280                    range: start..end,
6281                })
6282            }
6283        }
6284    }
6285
6286    fn excerpt(&self) -> Option<&'a Excerpt> {
6287        self.excerpts.item()
6288    }
6289}
6290
6291impl History {
6292    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6293        self.transaction_depth += 1;
6294        if self.transaction_depth == 1 {
6295            let id = self.next_transaction_id.tick();
6296            self.undo_stack.push(Transaction {
6297                id,
6298                buffer_transactions: Default::default(),
6299                first_edit_at: now,
6300                last_edit_at: now,
6301                suppress_grouping: false,
6302            });
6303            Some(id)
6304        } else {
6305            None
6306        }
6307    }
6308
6309    fn end_transaction(
6310        &mut self,
6311        now: Instant,
6312        buffer_transactions: HashMap<BufferId, TransactionId>,
6313    ) -> bool {
6314        assert_ne!(self.transaction_depth, 0);
6315        self.transaction_depth -= 1;
6316        if self.transaction_depth == 0 {
6317            if buffer_transactions.is_empty() {
6318                self.undo_stack.pop();
6319                false
6320            } else {
6321                self.redo_stack.clear();
6322                let transaction = self.undo_stack.last_mut().unwrap();
6323                transaction.last_edit_at = now;
6324                for (buffer_id, transaction_id) in buffer_transactions {
6325                    transaction
6326                        .buffer_transactions
6327                        .entry(buffer_id)
6328                        .or_insert(transaction_id);
6329                }
6330                true
6331            }
6332        } else {
6333            false
6334        }
6335    }
6336
6337    fn push_transaction<'a, T>(
6338        &mut self,
6339        buffer_transactions: T,
6340        now: Instant,
6341        cx: &Context<MultiBuffer>,
6342    ) where
6343        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6344    {
6345        assert_eq!(self.transaction_depth, 0);
6346        let transaction = Transaction {
6347            id: self.next_transaction_id.tick(),
6348            buffer_transactions: buffer_transactions
6349                .into_iter()
6350                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6351                .collect(),
6352            first_edit_at: now,
6353            last_edit_at: now,
6354            suppress_grouping: false,
6355        };
6356        if !transaction.buffer_transactions.is_empty() {
6357            self.undo_stack.push(transaction);
6358            self.redo_stack.clear();
6359        }
6360    }
6361
6362    fn finalize_last_transaction(&mut self) {
6363        if let Some(transaction) = self.undo_stack.last_mut() {
6364            transaction.suppress_grouping = true;
6365        }
6366    }
6367
6368    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6369        if let Some(ix) = self
6370            .undo_stack
6371            .iter()
6372            .rposition(|transaction| transaction.id == transaction_id)
6373        {
6374            Some(self.undo_stack.remove(ix))
6375        } else if let Some(ix) = self
6376            .redo_stack
6377            .iter()
6378            .rposition(|transaction| transaction.id == transaction_id)
6379        {
6380            Some(self.redo_stack.remove(ix))
6381        } else {
6382            None
6383        }
6384    }
6385
6386    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6387        self.undo_stack
6388            .iter()
6389            .find(|transaction| transaction.id == transaction_id)
6390            .or_else(|| {
6391                self.redo_stack
6392                    .iter()
6393                    .find(|transaction| transaction.id == transaction_id)
6394            })
6395    }
6396
6397    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6398        self.undo_stack
6399            .iter_mut()
6400            .find(|transaction| transaction.id == transaction_id)
6401            .or_else(|| {
6402                self.redo_stack
6403                    .iter_mut()
6404                    .find(|transaction| transaction.id == transaction_id)
6405            })
6406    }
6407
6408    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6409        assert_eq!(self.transaction_depth, 0);
6410        if let Some(transaction) = self.undo_stack.pop() {
6411            self.redo_stack.push(transaction);
6412            self.redo_stack.last_mut()
6413        } else {
6414            None
6415        }
6416    }
6417
6418    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6419        assert_eq!(self.transaction_depth, 0);
6420        if let Some(transaction) = self.redo_stack.pop() {
6421            self.undo_stack.push(transaction);
6422            self.undo_stack.last_mut()
6423        } else {
6424            None
6425        }
6426    }
6427
6428    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6429        let ix = self
6430            .undo_stack
6431            .iter()
6432            .rposition(|transaction| transaction.id == transaction_id)?;
6433        let transaction = self.undo_stack.remove(ix);
6434        self.redo_stack.push(transaction);
6435        self.redo_stack.last()
6436    }
6437
6438    fn group(&mut self) -> Option<TransactionId> {
6439        let mut count = 0;
6440        let mut transactions = self.undo_stack.iter();
6441        if let Some(mut transaction) = transactions.next_back() {
6442            while let Some(prev_transaction) = transactions.next_back() {
6443                if !prev_transaction.suppress_grouping
6444                    && transaction.first_edit_at - prev_transaction.last_edit_at
6445                        <= self.group_interval
6446                {
6447                    transaction = prev_transaction;
6448                    count += 1;
6449                } else {
6450                    break;
6451                }
6452            }
6453        }
6454        self.group_trailing(count)
6455    }
6456
6457    fn group_until(&mut self, transaction_id: TransactionId) {
6458        let mut count = 0;
6459        for transaction in self.undo_stack.iter().rev() {
6460            if transaction.id == transaction_id {
6461                self.group_trailing(count);
6462                break;
6463            } else if transaction.suppress_grouping {
6464                break;
6465            } else {
6466                count += 1;
6467            }
6468        }
6469    }
6470
6471    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6472        let new_len = self.undo_stack.len() - n;
6473        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6474        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6475            if let Some(transaction) = transactions_to_merge.last() {
6476                last_transaction.last_edit_at = transaction.last_edit_at;
6477            }
6478            for to_merge in transactions_to_merge {
6479                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6480                    last_transaction
6481                        .buffer_transactions
6482                        .entry(*buffer_id)
6483                        .or_insert(*transaction_id);
6484                }
6485            }
6486        }
6487
6488        self.undo_stack.truncate(new_len);
6489        self.undo_stack.last().map(|t| t.id)
6490    }
6491}
6492
6493impl Excerpt {
6494    fn new(
6495        id: ExcerptId,
6496        locator: Locator,
6497        buffer_id: BufferId,
6498        buffer: BufferSnapshot,
6499        range: ExcerptRange<text::Anchor>,
6500        has_trailing_newline: bool,
6501    ) -> Self {
6502        Excerpt {
6503            id,
6504            locator,
6505            max_buffer_row: range.context.end.to_point(&buffer).row,
6506            text_summary: buffer
6507                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6508            buffer_id,
6509            buffer,
6510            range,
6511            has_trailing_newline,
6512        }
6513    }
6514
6515    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6516        let content_start = self.range.context.start.to_offset(&self.buffer);
6517        let chunks_start = content_start + range.start;
6518        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6519
6520        let footer_height = if self.has_trailing_newline
6521            && range.start <= self.text_summary.len
6522            && range.end > self.text_summary.len
6523        {
6524            1
6525        } else {
6526            0
6527        };
6528
6529        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6530
6531        ExcerptChunks {
6532            excerpt_id: self.id,
6533            content_chunks,
6534            footer_height,
6535        }
6536    }
6537
6538    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6539        let content_start = self.range.context.start.to_offset(&self.buffer);
6540        let chunks_start = content_start + range.start;
6541        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6542        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6543        excerpt_chunks.footer_height = if self.has_trailing_newline
6544            && range.start <= self.text_summary.len
6545            && range.end > self.text_summary.len
6546        {
6547            1
6548        } else {
6549            0
6550        };
6551    }
6552
6553    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6554        if text_anchor
6555            .cmp(&self.range.context.start, &self.buffer)
6556            .is_lt()
6557        {
6558            self.range.context.start
6559        } else if text_anchor
6560            .cmp(&self.range.context.end, &self.buffer)
6561            .is_gt()
6562        {
6563            self.range.context.end
6564        } else {
6565            text_anchor
6566        }
6567    }
6568
6569    fn contains(&self, anchor: &Anchor) -> bool {
6570        Some(self.buffer_id) == anchor.buffer_id
6571            && self
6572                .range
6573                .context
6574                .start
6575                .cmp(&anchor.text_anchor, &self.buffer)
6576                .is_le()
6577            && self
6578                .range
6579                .context
6580                .end
6581                .cmp(&anchor.text_anchor, &self.buffer)
6582                .is_ge()
6583    }
6584
6585    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6586    fn buffer_start_offset(&self) -> usize {
6587        self.range.context.start.to_offset(&self.buffer)
6588    }
6589
6590    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6591    fn buffer_end_offset(&self) -> usize {
6592        self.buffer_start_offset() + self.text_summary.len
6593    }
6594}
6595
6596impl<'a> MultiBufferExcerpt<'a> {
6597    pub fn id(&self) -> ExcerptId {
6598        self.excerpt.id
6599    }
6600
6601    pub fn buffer_id(&self) -> BufferId {
6602        self.excerpt.buffer_id
6603    }
6604
6605    pub fn start_anchor(&self) -> Anchor {
6606        Anchor {
6607            buffer_id: Some(self.excerpt.buffer_id),
6608            excerpt_id: self.excerpt.id,
6609            text_anchor: self.excerpt.range.context.start,
6610            diff_base_anchor: None,
6611        }
6612    }
6613
6614    pub fn end_anchor(&self) -> Anchor {
6615        Anchor {
6616            buffer_id: Some(self.excerpt.buffer_id),
6617            excerpt_id: self.excerpt.id,
6618            text_anchor: self.excerpt.range.context.end,
6619            diff_base_anchor: None,
6620        }
6621    }
6622
6623    pub fn buffer(&self) -> &'a BufferSnapshot {
6624        &self.excerpt.buffer
6625    }
6626
6627    pub fn buffer_range(&self) -> Range<usize> {
6628        self.buffer_offset
6629            ..self
6630                .excerpt
6631                .range
6632                .context
6633                .end
6634                .to_offset(&self.excerpt.buffer.text)
6635    }
6636
6637    pub fn start_offset(&self) -> usize {
6638        self.offset
6639    }
6640
6641    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6642    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6643        self.map_range_to_buffer(offset..offset).start
6644    }
6645
6646    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6647    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6648        self.diff_transforms
6649            .seek(&OutputDimension(range.start), Bias::Right, &());
6650        let start = self.map_offset_to_buffer_internal(range.start);
6651        let end = if range.end > range.start {
6652            self.diff_transforms
6653                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6654            self.map_offset_to_buffer_internal(range.end)
6655        } else {
6656            start
6657        };
6658        start..end
6659    }
6660
6661    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6662        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6663        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6664            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6665        };
6666        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6667        self.buffer_offset + offset_in_excerpt
6668    }
6669
6670    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6671    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6672        self.map_range_from_buffer(buffer_offset..buffer_offset)
6673            .start
6674    }
6675
6676    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6677    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6678        if buffer_range.start < self.buffer_offset {
6679            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6680            return buffer_range;
6681        }
6682        let overshoot = buffer_range.start - self.buffer_offset;
6683        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6684        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6685        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6686            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6687            return buffer_range;
6688        }
6689        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6690        let start = self.diff_transforms.start().0 .0 + overshoot;
6691
6692        let end = if buffer_range.end > buffer_range.start {
6693            let overshoot = buffer_range.end - self.buffer_offset;
6694            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6695            self.diff_transforms
6696                .seek_forward(&excerpt_offset, Bias::Right, &());
6697            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6698            self.diff_transforms.start().0 .0 + overshoot
6699        } else {
6700            start
6701        };
6702
6703        start..end
6704    }
6705
6706    /// Returns true if the entirety of the given range is in the buffer's excerpt
6707    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6708        range.start >= self.excerpt.buffer_start_offset()
6709            && range.end <= self.excerpt.buffer_end_offset()
6710    }
6711
6712    pub fn max_buffer_row(&self) -> u32 {
6713        self.excerpt.max_buffer_row
6714    }
6715}
6716
6717impl ExcerptId {
6718    pub fn min() -> Self {
6719        Self(0)
6720    }
6721
6722    pub fn max() -> Self {
6723        Self(usize::MAX)
6724    }
6725
6726    pub fn to_proto(&self) -> u64 {
6727        self.0 as _
6728    }
6729
6730    pub fn from_proto(proto: u64) -> Self {
6731        Self(proto as _)
6732    }
6733
6734    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6735        let a = snapshot.excerpt_locator_for_id(*self);
6736        let b = snapshot.excerpt_locator_for_id(*other);
6737        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6738    }
6739}
6740
6741impl From<ExcerptId> for usize {
6742    fn from(val: ExcerptId) -> Self {
6743        val.0
6744    }
6745}
6746
6747impl fmt::Debug for Excerpt {
6748    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6749        f.debug_struct("Excerpt")
6750            .field("id", &self.id)
6751            .field("locator", &self.locator)
6752            .field("buffer_id", &self.buffer_id)
6753            .field("range", &self.range)
6754            .field("text_summary", &self.text_summary)
6755            .field("has_trailing_newline", &self.has_trailing_newline)
6756            .finish()
6757    }
6758}
6759
6760impl sum_tree::Item for Excerpt {
6761    type Summary = ExcerptSummary;
6762
6763    fn summary(&self, _cx: &()) -> Self::Summary {
6764        let mut text = self.text_summary;
6765        if self.has_trailing_newline {
6766            text += TextSummary::from("\n");
6767        }
6768        ExcerptSummary {
6769            excerpt_id: self.id,
6770            excerpt_locator: self.locator.clone(),
6771            widest_line_number: self.max_buffer_row,
6772            text,
6773        }
6774    }
6775}
6776
6777impl sum_tree::Item for ExcerptIdMapping {
6778    type Summary = ExcerptId;
6779
6780    fn summary(&self, _cx: &()) -> Self::Summary {
6781        self.id
6782    }
6783}
6784
6785impl sum_tree::KeyedItem for ExcerptIdMapping {
6786    type Key = ExcerptId;
6787
6788    fn key(&self) -> Self::Key {
6789        self.id
6790    }
6791}
6792
6793impl DiffTransform {
6794    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6795        match self {
6796            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6797            DiffTransform::BufferContent {
6798                inserted_hunk_info, ..
6799            } => *inserted_hunk_info,
6800        }
6801    }
6802}
6803
6804impl sum_tree::Item for DiffTransform {
6805    type Summary = DiffTransformSummary;
6806
6807    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6808        match self {
6809            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6810                input: *summary,
6811                output: *summary,
6812            },
6813            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6814                input: TextSummary::default(),
6815                output: *summary,
6816            },
6817        }
6818    }
6819}
6820
6821impl DiffTransformSummary {
6822    fn excerpt_len(&self) -> ExcerptOffset {
6823        ExcerptOffset::new(self.input.len)
6824    }
6825}
6826
6827impl sum_tree::Summary for DiffTransformSummary {
6828    type Context = ();
6829
6830    fn zero(_: &Self::Context) -> Self {
6831        DiffTransformSummary {
6832            input: TextSummary::default(),
6833            output: TextSummary::default(),
6834        }
6835    }
6836
6837    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6838        self.input += &summary.input;
6839        self.output += &summary.output;
6840    }
6841}
6842
6843impl sum_tree::Summary for ExcerptId {
6844    type Context = ();
6845
6846    fn zero(_cx: &()) -> Self {
6847        Default::default()
6848    }
6849
6850    fn add_summary(&mut self, other: &Self, _: &()) {
6851        *self = *other;
6852    }
6853}
6854
6855impl sum_tree::Summary for ExcerptSummary {
6856    type Context = ();
6857
6858    fn zero(_cx: &()) -> Self {
6859        Default::default()
6860    }
6861
6862    fn add_summary(&mut self, summary: &Self, _: &()) {
6863        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6864        self.excerpt_locator = summary.excerpt_locator.clone();
6865        self.text.add_summary(&summary.text, &());
6866        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6867    }
6868}
6869
6870impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6871    fn zero(_cx: &()) -> Self {
6872        Default::default()
6873    }
6874
6875    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6876        self.value += summary.text.len;
6877    }
6878}
6879
6880impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6881    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6882        Ord::cmp(&self.value, &cursor_location.text.len)
6883    }
6884}
6885
6886impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6887    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6888        Ord::cmp(&Some(self), cursor_location)
6889    }
6890}
6891
6892impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6893    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6894        Ord::cmp(self, &cursor_location.excerpt_locator)
6895    }
6896}
6897
6898impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6899    fn zero(_cx: &()) -> Self {
6900        Default::default()
6901    }
6902
6903    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6904        self.value += summary.text.lines;
6905    }
6906}
6907
6908impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6909    for ExcerptDimension<D>
6910{
6911    fn zero(_: &()) -> Self {
6912        ExcerptDimension(D::default())
6913    }
6914
6915    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6916        self.0.add_assign(&D::from_text_summary(&summary.text))
6917    }
6918}
6919
6920impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6921    fn zero(_cx: &()) -> Self {
6922        Default::default()
6923    }
6924
6925    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6926        *self = Some(&summary.excerpt_locator);
6927    }
6928}
6929
6930impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6931    fn zero(_cx: &()) -> Self {
6932        Default::default()
6933    }
6934
6935    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6936        *self = Some(summary.excerpt_id);
6937    }
6938}
6939
6940#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6941struct ExcerptDimension<T>(T);
6942
6943#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6944struct OutputDimension<T>(T);
6945
6946impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6947    fn zero(_: &()) -> Self {
6948        ExcerptOffset::new(0)
6949    }
6950
6951    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6952        self.value += summary.input.len;
6953    }
6954}
6955
6956impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6957    fn zero(_: &()) -> Self {
6958        ExcerptPoint::new(0, 0)
6959    }
6960
6961    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6962        self.value += summary.input.lines;
6963    }
6964}
6965
6966impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6967    for ExcerptDimension<D>
6968{
6969    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
6970        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6971    }
6972}
6973
6974impl<D: TextDimension + Ord>
6975    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
6976    for ExcerptDimension<D>
6977{
6978    fn cmp(
6979        &self,
6980        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
6981        _: &(),
6982    ) -> cmp::Ordering {
6983        Ord::cmp(&self.0, &cursor_location.1 .0)
6984    }
6985}
6986
6987impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6988    fn zero(_: &()) -> Self {
6989        ExcerptDimension(D::default())
6990    }
6991
6992    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6993        self.0.add_assign(&D::from_text_summary(&summary.input))
6994    }
6995}
6996
6997impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6998    fn zero(_: &()) -> Self {
6999        OutputDimension(D::default())
7000    }
7001
7002    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7003        self.0.add_assign(&D::from_text_summary(&summary.output))
7004    }
7005}
7006
7007impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7008    fn zero(_: &()) -> Self {
7009        TextSummary::default()
7010    }
7011
7012    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7013        *self += summary.output
7014    }
7015}
7016
7017impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7018    fn zero(_: &()) -> Self {
7019        0
7020    }
7021
7022    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7023        *self += summary.output.len
7024    }
7025}
7026
7027impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7028    fn zero(_: &()) -> Self {
7029        Point::new(0, 0)
7030    }
7031
7032    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7033        *self += summary.output.lines
7034    }
7035}
7036
7037impl MultiBufferRows<'_> {
7038    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7039        self.point = Point::new(row, 0);
7040        self.cursor.seek(&self.point);
7041    }
7042}
7043
7044impl Iterator for MultiBufferRows<'_> {
7045    type Item = RowInfo;
7046
7047    fn next(&mut self) -> Option<Self::Item> {
7048        if self.is_empty && self.point.row == 0 {
7049            self.point += Point::new(1, 0);
7050            return Some(RowInfo {
7051                buffer_id: None,
7052                buffer_row: Some(0),
7053                multibuffer_row: Some(MultiBufferRow(0)),
7054                diff_status: None,
7055            });
7056        }
7057
7058        let mut region = self.cursor.region()?;
7059        while self.point >= region.range.end {
7060            self.cursor.next();
7061            if let Some(next_region) = self.cursor.region() {
7062                region = next_region;
7063            } else {
7064                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7065                    let multibuffer_row = MultiBufferRow(self.point.row);
7066                    self.point += Point::new(1, 0);
7067                    let last_excerpt = self
7068                        .cursor
7069                        .excerpts
7070                        .item()
7071                        .or(self.cursor.excerpts.prev_item())?;
7072                    let last_row = last_excerpt
7073                        .range
7074                        .context
7075                        .end
7076                        .to_point(&last_excerpt.buffer)
7077                        .row;
7078                    return Some(RowInfo {
7079                        buffer_id: Some(last_excerpt.buffer_id),
7080                        buffer_row: Some(last_row),
7081                        multibuffer_row: Some(multibuffer_row),
7082                        diff_status: None,
7083                    });
7084                } else {
7085                    return None;
7086                }
7087            };
7088        }
7089
7090        let overshoot = self.point - region.range.start;
7091        let buffer_point = region.buffer_range.start + overshoot;
7092        let result = Some(RowInfo {
7093            buffer_id: Some(region.buffer.remote_id()),
7094            buffer_row: Some(buffer_point.row),
7095            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7096            diff_status: region
7097                .diff_hunk_status
7098                .filter(|_| self.point < region.range.end),
7099        });
7100        self.point += Point::new(1, 0);
7101        result
7102    }
7103}
7104
7105impl<'a> MultiBufferChunks<'a> {
7106    pub fn offset(&self) -> usize {
7107        self.range.start
7108    }
7109
7110    pub fn seek(&mut self, range: Range<usize>) {
7111        self.diff_transforms.seek(&range.end, Bias::Right, &());
7112        let mut excerpt_end = self.diff_transforms.start().1;
7113        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7114            let overshoot = range.end - self.diff_transforms.start().0;
7115            excerpt_end.value += overshoot;
7116        }
7117
7118        self.diff_transforms.seek(&range.start, Bias::Right, &());
7119        let mut excerpt_start = self.diff_transforms.start().1;
7120        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7121            let overshoot = range.start - self.diff_transforms.start().0;
7122            excerpt_start.value += overshoot;
7123        }
7124
7125        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7126        self.buffer_chunk.take();
7127        self.range = range;
7128    }
7129
7130    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7131        self.excerpt_offset_range = new_range.clone();
7132        self.excerpts.seek(&new_range.start, Bias::Right, &());
7133        if let Some(excerpt) = self.excerpts.item() {
7134            let excerpt_start = *self.excerpts.start();
7135            if let Some(excerpt_chunks) = self
7136                .excerpt_chunks
7137                .as_mut()
7138                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7139            {
7140                excerpt.seek_chunks(
7141                    excerpt_chunks,
7142                    (self.excerpt_offset_range.start - excerpt_start).value
7143                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7144                );
7145            } else {
7146                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7147                    (self.excerpt_offset_range.start - excerpt_start).value
7148                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7149                    self.language_aware,
7150                ));
7151            }
7152        } else {
7153            self.excerpt_chunks = None;
7154        }
7155    }
7156
7157    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7158        loop {
7159            if self.excerpt_offset_range.is_empty() {
7160                return None;
7161            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7162                self.excerpt_offset_range.start.value += chunk.text.len();
7163                return Some(chunk);
7164            } else {
7165                self.excerpts.next(&());
7166                let excerpt = self.excerpts.item()?;
7167                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7168                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7169                    self.language_aware,
7170                ));
7171            }
7172        }
7173    }
7174}
7175
7176impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7177    type Item = &'a str;
7178
7179    fn next(&mut self) -> Option<Self::Item> {
7180        let mut region = self.cursor.region()?;
7181        if self.offset == region.range.start {
7182            self.cursor.prev();
7183            region = self.cursor.region()?;
7184            let start_overshoot = self.start.saturating_sub(region.range.start);
7185            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7186                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7187            ));
7188        }
7189
7190        if self.offset == region.range.end && region.has_trailing_newline {
7191            self.offset -= 1;
7192            Some("\n")
7193        } else {
7194            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7195            self.offset -= chunk.len();
7196            Some(chunk)
7197        }
7198    }
7199}
7200
7201impl<'a> Iterator for MultiBufferChunks<'a> {
7202    type Item = Chunk<'a>;
7203
7204    fn next(&mut self) -> Option<Chunk<'a>> {
7205        if self.range.start >= self.range.end {
7206            return None;
7207        }
7208        if self.range.start == self.diff_transforms.end(&()).0 {
7209            self.diff_transforms.next(&());
7210        }
7211
7212        let diff_transform_start = self.diff_transforms.start().0;
7213        let diff_transform_end = self.diff_transforms.end(&()).0;
7214        debug_assert!(self.range.start < diff_transform_end);
7215
7216        let diff_transform = self.diff_transforms.item()?;
7217        match diff_transform {
7218            DiffTransform::BufferContent { .. } => {
7219                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7220                    chunk
7221                } else {
7222                    let chunk = self.next_excerpt_chunk().unwrap();
7223                    self.buffer_chunk.insert(chunk)
7224                };
7225
7226                let chunk_end = self.range.start + chunk.text.len();
7227                let diff_transform_end = diff_transform_end.min(self.range.end);
7228
7229                if diff_transform_end < chunk_end {
7230                    let (before, after) =
7231                        chunk.text.split_at(diff_transform_end - self.range.start);
7232                    self.range.start = diff_transform_end;
7233                    chunk.text = after;
7234                    Some(Chunk {
7235                        text: before,
7236                        ..chunk.clone()
7237                    })
7238                } else {
7239                    self.range.start = chunk_end;
7240                    self.buffer_chunk.take()
7241                }
7242            }
7243            DiffTransform::DeletedHunk {
7244                buffer_id,
7245                base_text_byte_range,
7246                has_trailing_newline,
7247                ..
7248            } => {
7249                let base_text_start =
7250                    base_text_byte_range.start + self.range.start - diff_transform_start;
7251                let base_text_end =
7252                    base_text_byte_range.start + self.range.end - diff_transform_start;
7253                let base_text_end = base_text_end.min(base_text_byte_range.end);
7254
7255                let mut chunks = if let Some((_, mut chunks)) = self
7256                    .diff_base_chunks
7257                    .take()
7258                    .filter(|(id, _)| id == buffer_id)
7259                {
7260                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7261                    {
7262                        chunks.seek(base_text_start..base_text_end);
7263                    }
7264                    chunks
7265                } else {
7266                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7267                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7268                };
7269
7270                let chunk = if let Some(chunk) = chunks.next() {
7271                    self.range.start += chunk.text.len();
7272                    self.diff_base_chunks = Some((*buffer_id, chunks));
7273                    chunk
7274                } else {
7275                    debug_assert!(has_trailing_newline);
7276                    self.range.start += "\n".len();
7277                    Chunk {
7278                        text: "\n",
7279                        ..Default::default()
7280                    }
7281                };
7282                Some(chunk)
7283            }
7284        }
7285    }
7286}
7287
7288impl MultiBufferBytes<'_> {
7289    fn consume(&mut self, len: usize) {
7290        self.range.start += len;
7291        self.chunk = &self.chunk[len..];
7292
7293        if !self.range.is_empty() && self.chunk.is_empty() {
7294            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7295                self.chunk = chunk;
7296            } else if self.has_trailing_newline {
7297                self.has_trailing_newline = false;
7298                self.chunk = b"\n";
7299            } else {
7300                self.cursor.next();
7301                if let Some(region) = self.cursor.region() {
7302                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7303                        region.buffer_range.start
7304                            ..(region.buffer_range.start + self.range.end - region.range.start)
7305                                .min(region.buffer_range.end),
7306                    );
7307                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7308                    self.excerpt_bytes = Some(excerpt_bytes);
7309                    self.has_trailing_newline =
7310                        region.has_trailing_newline && self.range.end >= region.range.end;
7311                    if self.chunk.is_empty() && self.has_trailing_newline {
7312                        self.has_trailing_newline = false;
7313                        self.chunk = b"\n";
7314                    }
7315                }
7316            }
7317        }
7318    }
7319}
7320
7321impl<'a> Iterator for MultiBufferBytes<'a> {
7322    type Item = &'a [u8];
7323
7324    fn next(&mut self) -> Option<Self::Item> {
7325        let chunk = self.chunk;
7326        if chunk.is_empty() {
7327            None
7328        } else {
7329            self.consume(chunk.len());
7330            Some(chunk)
7331        }
7332    }
7333}
7334
7335impl io::Read for MultiBufferBytes<'_> {
7336    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7337        let len = cmp::min(buf.len(), self.chunk.len());
7338        buf[..len].copy_from_slice(&self.chunk[..len]);
7339        if len > 0 {
7340            self.consume(len);
7341        }
7342        Ok(len)
7343    }
7344}
7345
7346impl io::Read for ReversedMultiBufferBytes<'_> {
7347    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7348        let len = cmp::min(buf.len(), self.chunk.len());
7349        buf[..len].copy_from_slice(&self.chunk[..len]);
7350        buf[..len].reverse();
7351        if len > 0 {
7352            self.range.end -= len;
7353            self.chunk = &self.chunk[..self.chunk.len() - len];
7354            if !self.range.is_empty() && self.chunk.is_empty() {
7355                if let Some(chunk) = self.chunks.next() {
7356                    self.chunk = chunk.as_bytes();
7357                }
7358            }
7359        }
7360        Ok(len)
7361    }
7362}
7363
7364impl<'a> Iterator for ExcerptChunks<'a> {
7365    type Item = Chunk<'a>;
7366
7367    fn next(&mut self) -> Option<Self::Item> {
7368        if let Some(chunk) = self.content_chunks.next() {
7369            return Some(chunk);
7370        }
7371
7372        if self.footer_height > 0 {
7373            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7374            self.footer_height = 0;
7375            return Some(Chunk {
7376                text,
7377                ..Default::default()
7378            });
7379        }
7380
7381        None
7382    }
7383}
7384
7385impl ToOffset for Point {
7386    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7387        snapshot.point_to_offset(*self)
7388    }
7389}
7390
7391impl ToOffset for usize {
7392    #[track_caller]
7393    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7394        assert!(*self <= snapshot.len(), "offset is out of range");
7395        *self
7396    }
7397}
7398
7399impl ToOffset for OffsetUtf16 {
7400    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7401        snapshot.offset_utf16_to_offset(*self)
7402    }
7403}
7404
7405impl ToOffset for PointUtf16 {
7406    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7407        snapshot.point_utf16_to_offset(*self)
7408    }
7409}
7410
7411impl ToOffsetUtf16 for OffsetUtf16 {
7412    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7413        *self
7414    }
7415}
7416
7417impl ToOffsetUtf16 for usize {
7418    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7419        snapshot.offset_to_offset_utf16(*self)
7420    }
7421}
7422
7423impl ToPoint for usize {
7424    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7425        snapshot.offset_to_point(*self)
7426    }
7427}
7428
7429impl ToPoint for Point {
7430    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7431        *self
7432    }
7433}
7434
7435impl ToPointUtf16 for usize {
7436    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7437        snapshot.offset_to_point_utf16(*self)
7438    }
7439}
7440
7441impl ToPointUtf16 for Point {
7442    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7443        snapshot.point_to_point_utf16(*self)
7444    }
7445}
7446
7447impl ToPointUtf16 for PointUtf16 {
7448    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7449        *self
7450    }
7451}
7452
7453impl From<ExcerptId> for EntityId {
7454    fn from(id: ExcerptId) -> Self {
7455        EntityId::from(id.0 as u64)
7456    }
7457}
7458
7459pub fn build_excerpt_ranges<T>(
7460    buffer: &BufferSnapshot,
7461    ranges: &[Range<T>],
7462    context_line_count: u32,
7463) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7464where
7465    T: text::ToPoint,
7466{
7467    let max_point = buffer.max_point();
7468    let mut range_counts = Vec::new();
7469    let mut excerpt_ranges = Vec::new();
7470    let mut range_iter = ranges
7471        .iter()
7472        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7473        .peekable();
7474    while let Some(range) = range_iter.next() {
7475        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7476        let row = (range.end.row + context_line_count).min(max_point.row);
7477        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7478
7479        let mut ranges_in_excerpt = 1;
7480
7481        while let Some(next_range) = range_iter.peek() {
7482            if next_range.start.row <= excerpt_end.row + context_line_count {
7483                let row = (next_range.end.row + context_line_count).min(max_point.row);
7484                excerpt_end = Point::new(row, buffer.line_len(row));
7485
7486                ranges_in_excerpt += 1;
7487                range_iter.next();
7488            } else {
7489                break;
7490            }
7491        }
7492
7493        excerpt_ranges.push(ExcerptRange {
7494            context: excerpt_start..excerpt_end,
7495            primary: Some(range),
7496        });
7497        range_counts.push(ranges_in_excerpt);
7498    }
7499
7500    (excerpt_ranges, range_counts)
7501}