multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{anyhow, Result};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{channel::mpsc, SinkExt};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    language_settings::{language_settings, IndentGuideSettings, LanguageSettings},
  21    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  22    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  23    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  24    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  25    Unclipped,
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  47use text::{
  48    locator::Locator,
  49    subscription::{Subscription, Topic},
  50    BufferId, Edit, LineIndent, TextSummary,
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    buffers_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    diffs: HashMap<BufferId, DiffState>,
  72    // all_diff_hunks_expanded: bool,
  73    subscriptions: Topic,
  74    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  75    singleton: bool,
  76    history: History,
  77    title: Option<String>,
  78    capability: Capability,
  79}
  80
  81#[derive(Clone, Debug, PartialEq, Eq)]
  82pub enum MultiOrSingleBufferOffsetRange {
  83    Single(Range<usize>),
  84    Multi(Range<usize>),
  85}
  86
  87#[derive(Clone, Debug, PartialEq, Eq)]
  88pub enum Event {
  89    ExcerptsAdded {
  90        buffer: Entity<Buffer>,
  91        predecessor: ExcerptId,
  92        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  93    },
  94    ExcerptsRemoved {
  95        ids: Vec<ExcerptId>,
  96    },
  97    ExcerptsExpanded {
  98        ids: Vec<ExcerptId>,
  99    },
 100    ExcerptsEdited {
 101        excerpt_ids: Vec<ExcerptId>,
 102        buffer_ids: Vec<BufferId>,
 103    },
 104    DiffHunksToggled,
 105    Edited {
 106        singleton_buffer_edited: bool,
 107        edited_buffer: Option<Entity<Buffer>>,
 108    },
 109    TransactionUndone {
 110        transaction_id: TransactionId,
 111    },
 112    Reloaded,
 113    ReloadNeeded,
 114
 115    LanguageChanged(BufferId),
 116    CapabilityChanged,
 117    Reparsed(BufferId),
 118    Saved,
 119    FileHandleChanged,
 120    Closed,
 121    Discarded,
 122    DirtyChanged,
 123    DiagnosticsUpdated,
 124}
 125
 126/// A diff hunk, representing a range of consequent lines in a multibuffer.
 127#[derive(Debug, Clone, PartialEq, Eq)]
 128pub struct MultiBufferDiffHunk {
 129    /// The row range in the multibuffer where this diff hunk appears.
 130    pub row_range: Range<MultiBufferRow>,
 131    /// The buffer ID that this hunk belongs to.
 132    pub buffer_id: BufferId,
 133    /// The range of the underlying buffer that this hunk corresponds to.
 134    pub buffer_range: Range<text::Anchor>,
 135    /// The excerpt that contains the diff hunk.
 136    pub excerpt_id: ExcerptId,
 137    /// The range within the buffer's diff base that this hunk corresponds to.
 138    pub diff_base_byte_range: Range<usize>,
 139    /// Whether or not this hunk also appears in the 'secondary diff'.
 140    pub secondary_status: DiffHunkSecondaryStatus,
 141}
 142
 143impl MultiBufferDiffHunk {
 144    pub fn status(&self) -> DiffHunkStatus {
 145        let kind = if self.buffer_range.start == self.buffer_range.end {
 146            DiffHunkStatusKind::Deleted
 147        } else if self.diff_base_byte_range.is_empty() {
 148            DiffHunkStatusKind::Added
 149        } else {
 150            DiffHunkStatusKind::Modified
 151        };
 152        DiffHunkStatus {
 153            kind,
 154            secondary: self.secondary_status,
 155        }
 156    }
 157}
 158
 159#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 160pub struct PathKey {
 161    namespace: &'static str,
 162    path: Arc<Path>,
 163}
 164
 165impl PathKey {
 166    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 167        Self { namespace, path }
 168    }
 169
 170    pub fn path(&self) -> &Arc<Path> {
 171        &self.path
 172    }
 173}
 174
 175pub type MultiBufferPoint = Point;
 176type ExcerptOffset = TypedOffset<Excerpt>;
 177type ExcerptPoint = TypedPoint<Excerpt>;
 178
 179#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 180#[serde(transparent)]
 181pub struct MultiBufferRow(pub u32);
 182
 183impl MultiBufferRow {
 184    pub const MIN: Self = Self(0);
 185    pub const MAX: Self = Self(u32::MAX);
 186}
 187
 188impl std::ops::Add<usize> for MultiBufferRow {
 189    type Output = Self;
 190
 191    fn add(self, rhs: usize) -> Self::Output {
 192        MultiBufferRow(self.0 + rhs as u32)
 193    }
 194}
 195
 196#[derive(Clone)]
 197struct History {
 198    next_transaction_id: TransactionId,
 199    undo_stack: Vec<Transaction>,
 200    redo_stack: Vec<Transaction>,
 201    transaction_depth: usize,
 202    group_interval: Duration,
 203}
 204
 205#[derive(Clone)]
 206struct Transaction {
 207    id: TransactionId,
 208    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 209    first_edit_at: Instant,
 210    last_edit_at: Instant,
 211    suppress_grouping: bool,
 212}
 213
 214pub trait ToOffset: 'static + fmt::Debug {
 215    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 216}
 217
 218pub trait ToOffsetUtf16: 'static + fmt::Debug {
 219    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 220}
 221
 222pub trait ToPoint: 'static + fmt::Debug {
 223    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 224}
 225
 226pub trait ToPointUtf16: 'static + fmt::Debug {
 227    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 228}
 229
 230struct BufferState {
 231    buffer: Entity<Buffer>,
 232    last_version: clock::Global,
 233    last_non_text_state_update_count: usize,
 234    excerpts: Vec<Locator>,
 235    _subscriptions: [gpui::Subscription; 2],
 236}
 237
 238struct DiffState {
 239    diff: Entity<BufferDiff>,
 240    _subscription: gpui::Subscription,
 241}
 242
 243impl DiffState {
 244    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 245        DiffState {
 246            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 247                BufferDiffEvent::DiffChanged { changed_range } => {
 248                    if let Some(changed_range) = changed_range.clone() {
 249                        this.buffer_diff_changed(diff, changed_range, cx)
 250                    }
 251                }
 252                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 253            }),
 254            diff,
 255        }
 256    }
 257}
 258
 259/// The contents of a [`MultiBuffer`] at a single point in time.
 260#[derive(Clone, Default)]
 261pub struct MultiBufferSnapshot {
 262    singleton: bool,
 263    excerpts: SumTree<Excerpt>,
 264    excerpt_ids: SumTree<ExcerptIdMapping>,
 265    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 266    diff_transforms: SumTree<DiffTransform>,
 267    trailing_excerpt_update_count: usize,
 268    all_diff_hunks_expanded: bool,
 269    non_text_state_update_count: usize,
 270    edit_count: usize,
 271    is_dirty: bool,
 272    has_deleted_file: bool,
 273    has_conflict: bool,
 274    show_headers: bool,
 275}
 276
 277#[derive(Debug, Clone)]
 278enum DiffTransform {
 279    BufferContent {
 280        summary: TextSummary,
 281        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 282    },
 283    DeletedHunk {
 284        summary: TextSummary,
 285        buffer_id: BufferId,
 286        hunk_info: DiffTransformHunkInfo,
 287        base_text_byte_range: Range<usize>,
 288        has_trailing_newline: bool,
 289    },
 290}
 291
 292#[derive(Clone, Copy, Debug)]
 293struct DiffTransformHunkInfo {
 294    excerpt_id: ExcerptId,
 295    hunk_start_anchor: text::Anchor,
 296    hunk_secondary_status: DiffHunkSecondaryStatus,
 297}
 298
 299impl Eq for DiffTransformHunkInfo {}
 300
 301impl PartialEq for DiffTransformHunkInfo {
 302    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 303        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 304    }
 305}
 306
 307impl std::hash::Hash for DiffTransformHunkInfo {
 308    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 309        self.excerpt_id.hash(state);
 310        self.hunk_start_anchor.hash(state);
 311    }
 312}
 313
 314#[derive(Clone)]
 315pub struct ExcerptInfo {
 316    pub id: ExcerptId,
 317    pub buffer: BufferSnapshot,
 318    pub buffer_id: BufferId,
 319    pub range: ExcerptRange<text::Anchor>,
 320    pub end_row: MultiBufferRow,
 321}
 322
 323impl std::fmt::Debug for ExcerptInfo {
 324    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 325        f.debug_struct(type_name::<Self>())
 326            .field("id", &self.id)
 327            .field("buffer_id", &self.buffer_id)
 328            .field("path", &self.buffer.file().map(|f| f.path()))
 329            .field("range", &self.range)
 330            .finish()
 331    }
 332}
 333
 334/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 335#[derive(Debug)]
 336pub struct ExcerptBoundary {
 337    pub prev: Option<ExcerptInfo>,
 338    pub next: Option<ExcerptInfo>,
 339    /// The row in the `MultiBuffer` where the boundary is located
 340    pub row: MultiBufferRow,
 341}
 342
 343impl ExcerptBoundary {
 344    pub fn starts_new_buffer(&self) -> bool {
 345        match (self.prev.as_ref(), self.next.as_ref()) {
 346            (None, _) => true,
 347            (Some(_), None) => false,
 348            (Some(prev), Some(next)) => prev.buffer_id != next.buffer_id,
 349        }
 350    }
 351}
 352
 353#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 354pub struct RowInfo {
 355    pub buffer_id: Option<BufferId>,
 356    pub buffer_row: Option<u32>,
 357    pub multibuffer_row: Option<MultiBufferRow>,
 358    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 359}
 360
 361/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 362#[derive(Clone)]
 363struct Excerpt {
 364    /// The unique identifier for this excerpt
 365    id: ExcerptId,
 366    /// The location of the excerpt in the [`MultiBuffer`]
 367    locator: Locator,
 368    /// The buffer being excerpted
 369    buffer_id: BufferId,
 370    /// A snapshot of the buffer being excerpted
 371    buffer: BufferSnapshot,
 372    /// The range of the buffer to be shown in the excerpt
 373    range: ExcerptRange<text::Anchor>,
 374    /// The last row in the excerpted slice of the buffer
 375    max_buffer_row: BufferRow,
 376    /// A summary of the text in the excerpt
 377    text_summary: TextSummary,
 378    has_trailing_newline: bool,
 379}
 380
 381/// A public view into an `Excerpt` in a [`MultiBuffer`].
 382///
 383/// Contains methods for getting the [`Buffer`] of the excerpt,
 384/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 385#[derive(Clone)]
 386pub struct MultiBufferExcerpt<'a> {
 387    excerpt: &'a Excerpt,
 388    diff_transforms:
 389        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 390    offset: usize,
 391    excerpt_offset: ExcerptDimension<usize>,
 392    buffer_offset: usize,
 393}
 394
 395#[derive(Clone, Debug)]
 396struct ExcerptIdMapping {
 397    id: ExcerptId,
 398    locator: Locator,
 399}
 400
 401/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 402/// These ranges are relative to the buffer itself
 403#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 404pub struct ExcerptRange<T> {
 405    /// The full range of text to be shown in the excerpt.
 406    pub context: Range<T>,
 407    /// The primary range of text to be highlighted in the excerpt.
 408    /// In a multi-buffer search, this would be the text that matched the search
 409    pub primary: Option<Range<T>>,
 410}
 411
 412#[derive(Clone, Debug, Default)]
 413pub struct ExcerptSummary {
 414    excerpt_id: ExcerptId,
 415    /// The location of the last [`Excerpt`] being summarized
 416    excerpt_locator: Locator,
 417    widest_line_number: u32,
 418    text: TextSummary,
 419}
 420
 421#[derive(Debug, Clone)]
 422pub struct DiffTransformSummary {
 423    input: TextSummary,
 424    output: TextSummary,
 425}
 426
 427#[derive(Clone)]
 428pub struct MultiBufferRows<'a> {
 429    point: Point,
 430    is_empty: bool,
 431    cursor: MultiBufferCursor<'a, Point>,
 432}
 433
 434pub struct MultiBufferChunks<'a> {
 435    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 436    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 437    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 438    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 439    buffer_chunk: Option<Chunk<'a>>,
 440    range: Range<usize>,
 441    excerpt_offset_range: Range<ExcerptOffset>,
 442    excerpt_chunks: Option<ExcerptChunks<'a>>,
 443    language_aware: bool,
 444}
 445
 446pub struct ReversedMultiBufferChunks<'a> {
 447    cursor: MultiBufferCursor<'a, usize>,
 448    current_chunks: Option<rope::Chunks<'a>>,
 449    start: usize,
 450    offset: usize,
 451}
 452
 453pub struct MultiBufferBytes<'a> {
 454    range: Range<usize>,
 455    cursor: MultiBufferCursor<'a, usize>,
 456    excerpt_bytes: Option<text::Bytes<'a>>,
 457    has_trailing_newline: bool,
 458    chunk: &'a [u8],
 459}
 460
 461pub struct ReversedMultiBufferBytes<'a> {
 462    range: Range<usize>,
 463    chunks: ReversedMultiBufferChunks<'a>,
 464    chunk: &'a [u8],
 465}
 466
 467#[derive(Clone)]
 468struct MultiBufferCursor<'a, D: TextDimension> {
 469    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 470    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 471    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 472    cached_region: Option<MultiBufferRegion<'a, D>>,
 473}
 474
 475#[derive(Clone)]
 476struct MultiBufferRegion<'a, D: TextDimension> {
 477    buffer: &'a BufferSnapshot,
 478    is_main_buffer: bool,
 479    diff_hunk_status: Option<DiffHunkStatus>,
 480    excerpt: &'a Excerpt,
 481    buffer_range: Range<D>,
 482    range: Range<D>,
 483    has_trailing_newline: bool,
 484}
 485
 486struct ExcerptChunks<'a> {
 487    excerpt_id: ExcerptId,
 488    content_chunks: BufferChunks<'a>,
 489    footer_height: usize,
 490}
 491
 492#[derive(Debug)]
 493struct BufferEdit {
 494    range: Range<usize>,
 495    new_text: Arc<str>,
 496    is_insertion: bool,
 497    original_start_column: u32,
 498    excerpt_id: ExcerptId,
 499}
 500
 501#[derive(Clone, Copy, Debug, PartialEq)]
 502enum DiffChangeKind {
 503    BufferEdited,
 504    DiffUpdated { base_changed: bool },
 505    ExpandOrCollapseHunks { expand: bool },
 506}
 507
 508#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 509pub enum ExpandExcerptDirection {
 510    Up,
 511    Down,
 512    UpAndDown,
 513}
 514
 515impl ExpandExcerptDirection {
 516    pub fn should_expand_up(&self) -> bool {
 517        match self {
 518            ExpandExcerptDirection::Up => true,
 519            ExpandExcerptDirection::Down => false,
 520            ExpandExcerptDirection::UpAndDown => true,
 521        }
 522    }
 523
 524    pub fn should_expand_down(&self) -> bool {
 525        match self {
 526            ExpandExcerptDirection::Up => false,
 527            ExpandExcerptDirection::Down => true,
 528            ExpandExcerptDirection::UpAndDown => true,
 529        }
 530    }
 531}
 532
 533#[derive(Clone, Debug, PartialEq)]
 534pub struct IndentGuide {
 535    pub buffer_id: BufferId,
 536    pub start_row: MultiBufferRow,
 537    pub end_row: MultiBufferRow,
 538    pub depth: u32,
 539    pub tab_size: u32,
 540    pub settings: IndentGuideSettings,
 541}
 542
 543impl IndentGuide {
 544    pub fn indent_level(&self) -> u32 {
 545        self.depth * self.tab_size
 546    }
 547}
 548
 549impl MultiBuffer {
 550    pub fn new(capability: Capability) -> Self {
 551        Self {
 552            snapshot: RefCell::new(MultiBufferSnapshot {
 553                show_headers: true,
 554                ..MultiBufferSnapshot::default()
 555            }),
 556            buffers: RefCell::default(),
 557            diffs: HashMap::default(),
 558            subscriptions: Topic::default(),
 559            singleton: false,
 560            capability,
 561            title: None,
 562            buffers_by_path: Default::default(),
 563            history: History {
 564                next_transaction_id: clock::Lamport::default(),
 565                undo_stack: Vec::new(),
 566                redo_stack: Vec::new(),
 567                transaction_depth: 0,
 568                group_interval: Duration::from_millis(300),
 569            },
 570        }
 571    }
 572
 573    pub fn without_headers(capability: Capability) -> Self {
 574        Self {
 575            snapshot: Default::default(),
 576            buffers: Default::default(),
 577            buffers_by_path: Default::default(),
 578            diffs: HashMap::default(),
 579            subscriptions: Default::default(),
 580            singleton: false,
 581            capability,
 582            history: History {
 583                next_transaction_id: Default::default(),
 584                undo_stack: Default::default(),
 585                redo_stack: Default::default(),
 586                transaction_depth: 0,
 587                group_interval: Duration::from_millis(300),
 588            },
 589            title: Default::default(),
 590        }
 591    }
 592
 593    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 594        let mut buffers = HashMap::default();
 595        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 596            buffers.insert(
 597                *buffer_id,
 598                BufferState {
 599                    buffer: buffer_state.buffer.clone(),
 600                    last_version: buffer_state.last_version.clone(),
 601                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 602                    excerpts: buffer_state.excerpts.clone(),
 603                    _subscriptions: [
 604                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 605                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 606                    ],
 607                },
 608            );
 609        }
 610        let mut diff_bases = HashMap::default();
 611        for (buffer_id, diff) in self.diffs.iter() {
 612            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 613        }
 614        Self {
 615            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 616            buffers: RefCell::new(buffers),
 617            buffers_by_path: Default::default(),
 618            diffs: diff_bases,
 619            subscriptions: Default::default(),
 620            singleton: self.singleton,
 621            capability: self.capability,
 622            history: self.history.clone(),
 623            title: self.title.clone(),
 624        }
 625    }
 626
 627    pub fn with_title(mut self, title: String) -> Self {
 628        self.title = Some(title);
 629        self
 630    }
 631
 632    pub fn read_only(&self) -> bool {
 633        self.capability == Capability::ReadOnly
 634    }
 635
 636    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 637        let mut this = Self::new(buffer.read(cx).capability());
 638        this.singleton = true;
 639        this.push_excerpts(
 640            buffer,
 641            [ExcerptRange {
 642                context: text::Anchor::MIN..text::Anchor::MAX,
 643                primary: None,
 644            }],
 645            cx,
 646        );
 647        this.snapshot.borrow_mut().singleton = true;
 648        this
 649    }
 650
 651    /// Returns an up-to-date snapshot of the MultiBuffer.
 652    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 653        self.sync(cx);
 654        self.snapshot.borrow().clone()
 655    }
 656
 657    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 658        self.sync(cx);
 659        self.snapshot.borrow()
 660    }
 661
 662    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 663        if self.singleton {
 664            return Some(
 665                self.buffers
 666                    .borrow()
 667                    .values()
 668                    .next()
 669                    .unwrap()
 670                    .buffer
 671                    .clone(),
 672            );
 673        } else {
 674            None
 675        }
 676    }
 677
 678    pub fn is_singleton(&self) -> bool {
 679        self.singleton
 680    }
 681
 682    pub fn subscribe(&mut self) -> Subscription {
 683        self.subscriptions.subscribe()
 684    }
 685
 686    pub fn is_dirty(&self, cx: &App) -> bool {
 687        self.read(cx).is_dirty()
 688    }
 689
 690    pub fn has_deleted_file(&self, cx: &App) -> bool {
 691        self.read(cx).has_deleted_file()
 692    }
 693
 694    pub fn has_conflict(&self, cx: &App) -> bool {
 695        self.read(cx).has_conflict()
 696    }
 697
 698    // The `is_empty` signature doesn't match what clippy expects
 699    #[allow(clippy::len_without_is_empty)]
 700    pub fn len(&self, cx: &App) -> usize {
 701        self.read(cx).len()
 702    }
 703
 704    pub fn is_empty(&self) -> bool {
 705        self.buffers.borrow().is_empty()
 706    }
 707
 708    pub fn symbols_containing<T: ToOffset>(
 709        &self,
 710        offset: T,
 711        theme: Option<&SyntaxTheme>,
 712        cx: &App,
 713    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 714        self.read(cx).symbols_containing(offset, theme)
 715    }
 716
 717    pub fn edit<I, S, T>(
 718        &self,
 719        edits: I,
 720        autoindent_mode: Option<AutoindentMode>,
 721        cx: &mut Context<Self>,
 722    ) where
 723        I: IntoIterator<Item = (Range<S>, T)>,
 724        S: ToOffset,
 725        T: Into<Arc<str>>,
 726    {
 727        let snapshot = self.read(cx);
 728        let edits = edits
 729            .into_iter()
 730            .map(|(range, new_text)| {
 731                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 732                if range.start > range.end {
 733                    mem::swap(&mut range.start, &mut range.end);
 734                }
 735                (range, new_text.into())
 736            })
 737            .collect::<Vec<_>>();
 738
 739        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 740
 741        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 742        fn edit_internal(
 743            this: &MultiBuffer,
 744            snapshot: Ref<MultiBufferSnapshot>,
 745            edits: Vec<(Range<usize>, Arc<str>)>,
 746            mut autoindent_mode: Option<AutoindentMode>,
 747            cx: &mut Context<MultiBuffer>,
 748        ) {
 749            if this.read_only() || this.buffers.borrow().is_empty() {
 750                return;
 751            }
 752
 753            let original_start_columns = match &mut autoindent_mode {
 754                Some(AutoindentMode::Block {
 755                    original_start_columns,
 756                }) => mem::take(original_start_columns),
 757                _ => Default::default(),
 758            };
 759
 760            let (buffer_edits, edited_excerpt_ids) =
 761                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_start_columns);
 762            drop(snapshot);
 763
 764            let mut buffer_ids = Vec::new();
 765            for (buffer_id, mut edits) in buffer_edits {
 766                buffer_ids.push(buffer_id);
 767                edits.sort_by_key(|edit| edit.range.start);
 768                this.buffers.borrow()[&buffer_id]
 769                    .buffer
 770                    .update(cx, |buffer, cx| {
 771                        let mut edits = edits.into_iter().peekable();
 772                        let mut insertions = Vec::new();
 773                        let mut original_indent_columns = Vec::new();
 774                        let mut deletions = Vec::new();
 775                        let empty_str: Arc<str> = Arc::default();
 776                        while let Some(BufferEdit {
 777                            mut range,
 778                            mut new_text,
 779                            mut is_insertion,
 780                            original_start_column: original_indent_column,
 781                            excerpt_id,
 782                        }) = edits.next()
 783                        {
 784                            while let Some(BufferEdit {
 785                                range: next_range,
 786                                is_insertion: next_is_insertion,
 787                                new_text: next_new_text,
 788                                excerpt_id: next_excerpt_id,
 789                                ..
 790                            }) = edits.peek()
 791                            {
 792                                if range.end >= next_range.start {
 793                                    range.end = cmp::max(next_range.end, range.end);
 794                                    is_insertion |= *next_is_insertion;
 795                                    if excerpt_id == *next_excerpt_id {
 796                                        new_text = format!("{new_text}{next_new_text}").into();
 797                                    }
 798                                    edits.next();
 799                                } else {
 800                                    break;
 801                                }
 802                            }
 803
 804                            if is_insertion {
 805                                original_indent_columns.push(original_indent_column);
 806                                insertions.push((
 807                                    buffer.anchor_before(range.start)
 808                                        ..buffer.anchor_before(range.end),
 809                                    new_text.clone(),
 810                                ));
 811                            } else if !range.is_empty() {
 812                                deletions.push((
 813                                    buffer.anchor_before(range.start)
 814                                        ..buffer.anchor_before(range.end),
 815                                    empty_str.clone(),
 816                                ));
 817                            }
 818                        }
 819
 820                        let deletion_autoindent_mode =
 821                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 822                                Some(AutoindentMode::Block {
 823                                    original_start_columns: Default::default(),
 824                                })
 825                            } else {
 826                                autoindent_mode.clone()
 827                            };
 828                        let insertion_autoindent_mode =
 829                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 830                                Some(AutoindentMode::Block {
 831                                    original_start_columns: original_indent_columns,
 832                                })
 833                            } else {
 834                                autoindent_mode.clone()
 835                            };
 836
 837                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 838                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 839                    })
 840            }
 841
 842            cx.emit(Event::ExcerptsEdited {
 843                excerpt_ids: edited_excerpt_ids,
 844                buffer_ids,
 845            });
 846        }
 847    }
 848
 849    fn convert_edits_to_buffer_edits(
 850        &self,
 851        edits: Vec<(Range<usize>, Arc<str>)>,
 852        snapshot: &MultiBufferSnapshot,
 853        original_start_columns: &[u32],
 854    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 855        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 856        let mut edited_excerpt_ids = Vec::new();
 857        let mut cursor = snapshot.cursor::<usize>();
 858        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 859            let original_start_column = original_start_columns.get(ix).copied().unwrap_or(0);
 860
 861            cursor.seek(&range.start);
 862            let mut start_region = cursor.region().expect("start offset out of bounds");
 863            if !start_region.is_main_buffer {
 864                cursor.next();
 865                if let Some(region) = cursor.region() {
 866                    start_region = region;
 867                } else {
 868                    continue;
 869                }
 870            }
 871
 872            if range.end < start_region.range.start {
 873                continue;
 874            }
 875
 876            if range.end > start_region.range.end {
 877                cursor.seek_forward(&range.end);
 878            }
 879            let mut end_region = cursor.region().expect("end offset out of bounds");
 880            if !end_region.is_main_buffer {
 881                cursor.prev();
 882                if let Some(region) = cursor.region() {
 883                    end_region = region;
 884                } else {
 885                    continue;
 886                }
 887            }
 888
 889            if range.start > end_region.range.end {
 890                continue;
 891            }
 892
 893            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 894            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 895            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 896                .min(start_region.buffer_range.end);
 897            let buffer_end =
 898                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 899
 900            if start_region.excerpt.id == end_region.excerpt.id {
 901                if start_region.is_main_buffer {
 902                    edited_excerpt_ids.push(start_region.excerpt.id);
 903                    buffer_edits
 904                        .entry(start_region.buffer.remote_id())
 905                        .or_default()
 906                        .push(BufferEdit {
 907                            range: buffer_start..buffer_end,
 908                            new_text,
 909                            is_insertion: true,
 910                            original_start_column,
 911                            excerpt_id: start_region.excerpt.id,
 912                        });
 913                }
 914            } else {
 915                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 916                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 917                if start_region.is_main_buffer {
 918                    edited_excerpt_ids.push(start_region.excerpt.id);
 919                    buffer_edits
 920                        .entry(start_region.buffer.remote_id())
 921                        .or_default()
 922                        .push(BufferEdit {
 923                            range: start_excerpt_range,
 924                            new_text: new_text.clone(),
 925                            is_insertion: true,
 926                            original_start_column,
 927                            excerpt_id: start_region.excerpt.id,
 928                        });
 929                }
 930                if end_region.is_main_buffer {
 931                    edited_excerpt_ids.push(end_region.excerpt.id);
 932                    buffer_edits
 933                        .entry(end_region.buffer.remote_id())
 934                        .or_default()
 935                        .push(BufferEdit {
 936                            range: end_excerpt_range,
 937                            new_text: new_text.clone(),
 938                            is_insertion: false,
 939                            original_start_column,
 940                            excerpt_id: end_region.excerpt.id,
 941                        });
 942                }
 943
 944                cursor.seek(&range.start);
 945                cursor.next_excerpt();
 946                while let Some(region) = cursor.region() {
 947                    if region.excerpt.id == end_region.excerpt.id {
 948                        break;
 949                    }
 950                    if region.is_main_buffer {
 951                        edited_excerpt_ids.push(region.excerpt.id);
 952                        buffer_edits
 953                            .entry(region.buffer.remote_id())
 954                            .or_default()
 955                            .push(BufferEdit {
 956                                range: region.buffer_range,
 957                                new_text: new_text.clone(),
 958                                is_insertion: false,
 959                                original_start_column,
 960                                excerpt_id: region.excerpt.id,
 961                            });
 962                    }
 963                    cursor.next_excerpt();
 964                }
 965            }
 966        }
 967        (buffer_edits, edited_excerpt_ids)
 968    }
 969
 970    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
 971    where
 972        I: IntoIterator<Item = Range<S>>,
 973        S: ToOffset,
 974    {
 975        let snapshot = self.read(cx);
 976        let empty = Arc::<str>::from("");
 977        let edits = ranges
 978            .into_iter()
 979            .map(|range| {
 980                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 981                if range.start > range.end {
 982                    mem::swap(&mut range.start, &mut range.end);
 983                }
 984                (range, empty.clone())
 985            })
 986            .collect::<Vec<_>>();
 987
 988        return autoindent_ranges_internal(self, snapshot, edits, cx);
 989
 990        fn autoindent_ranges_internal(
 991            this: &MultiBuffer,
 992            snapshot: Ref<MultiBufferSnapshot>,
 993            edits: Vec<(Range<usize>, Arc<str>)>,
 994            cx: &mut Context<MultiBuffer>,
 995        ) {
 996            if this.read_only() || this.buffers.borrow().is_empty() {
 997                return;
 998            }
 999
1000            let (buffer_edits, edited_excerpt_ids) =
1001                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1002            drop(snapshot);
1003
1004            let mut buffer_ids = Vec::new();
1005            for (buffer_id, mut edits) in buffer_edits {
1006                buffer_ids.push(buffer_id);
1007                edits.sort_unstable_by_key(|edit| edit.range.start);
1008
1009                let mut ranges: Vec<Range<usize>> = Vec::new();
1010                for edit in edits {
1011                    if let Some(last_range) = ranges.last_mut() {
1012                        if edit.range.start <= last_range.end {
1013                            last_range.end = last_range.end.max(edit.range.end);
1014                            continue;
1015                        }
1016                    }
1017                    ranges.push(edit.range);
1018                }
1019
1020                this.buffers.borrow()[&buffer_id]
1021                    .buffer
1022                    .update(cx, |buffer, cx| {
1023                        buffer.autoindent_ranges(ranges, cx);
1024                    })
1025            }
1026
1027            cx.emit(Event::ExcerptsEdited {
1028                excerpt_ids: edited_excerpt_ids,
1029                buffer_ids,
1030            });
1031        }
1032    }
1033
1034    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1035    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1036    // Panics if the given position is invalid.
1037    pub fn insert_empty_line(
1038        &mut self,
1039        position: impl ToPoint,
1040        space_above: bool,
1041        space_below: bool,
1042        cx: &mut Context<Self>,
1043    ) -> Point {
1044        let multibuffer_point = position.to_point(&self.read(cx));
1045        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1046        self.start_transaction(cx);
1047        let empty_line_start = buffer.update(cx, |buffer, cx| {
1048            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1049        });
1050        self.end_transaction(cx);
1051        multibuffer_point + (empty_line_start - buffer_point)
1052    }
1053
1054    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1055        self.start_transaction_at(Instant::now(), cx)
1056    }
1057
1058    pub fn start_transaction_at(
1059        &mut self,
1060        now: Instant,
1061        cx: &mut Context<Self>,
1062    ) -> Option<TransactionId> {
1063        if let Some(buffer) = self.as_singleton() {
1064            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1065        }
1066
1067        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1068            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1069        }
1070        self.history.start_transaction(now)
1071    }
1072
1073    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1074        self.end_transaction_at(Instant::now(), cx)
1075    }
1076
1077    pub fn end_transaction_at(
1078        &mut self,
1079        now: Instant,
1080        cx: &mut Context<Self>,
1081    ) -> Option<TransactionId> {
1082        if let Some(buffer) = self.as_singleton() {
1083            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1084        }
1085
1086        let mut buffer_transactions = HashMap::default();
1087        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1088            if let Some(transaction_id) =
1089                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1090            {
1091                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1092            }
1093        }
1094
1095        if self.history.end_transaction(now, buffer_transactions) {
1096            let transaction_id = self.history.group().unwrap();
1097            Some(transaction_id)
1098        } else {
1099            None
1100        }
1101    }
1102
1103    pub fn edited_ranges_for_transaction<D>(
1104        &self,
1105        transaction_id: TransactionId,
1106        cx: &App,
1107    ) -> Vec<Range<D>>
1108    where
1109        D: TextDimension + Ord + Sub<D, Output = D>,
1110    {
1111        let Some(transaction) = self.history.transaction(transaction_id) else {
1112            return Vec::new();
1113        };
1114
1115        let mut ranges = Vec::new();
1116        let snapshot = self.read(cx);
1117        let buffers = self.buffers.borrow();
1118        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1119
1120        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1121            let Some(buffer_state) = buffers.get(buffer_id) else {
1122                continue;
1123            };
1124
1125            let buffer = buffer_state.buffer.read(cx);
1126            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1127                for excerpt_id in &buffer_state.excerpts {
1128                    cursor.seek(excerpt_id, Bias::Left, &());
1129                    if let Some(excerpt) = cursor.item() {
1130                        if excerpt.locator == *excerpt_id {
1131                            let excerpt_buffer_start =
1132                                excerpt.range.context.start.summary::<D>(buffer);
1133                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1134                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1135                            if excerpt_range.contains(&range.start)
1136                                && excerpt_range.contains(&range.end)
1137                            {
1138                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1139
1140                                let mut start = excerpt_start;
1141                                start.add_assign(&(range.start - excerpt_buffer_start));
1142                                let mut end = excerpt_start;
1143                                end.add_assign(&(range.end - excerpt_buffer_start));
1144
1145                                ranges.push(start..end);
1146                                break;
1147                            }
1148                        }
1149                    }
1150                }
1151            }
1152        }
1153
1154        ranges.sort_by_key(|range| range.start);
1155        ranges
1156    }
1157
1158    pub fn merge_transactions(
1159        &mut self,
1160        transaction: TransactionId,
1161        destination: TransactionId,
1162        cx: &mut Context<Self>,
1163    ) {
1164        if let Some(buffer) = self.as_singleton() {
1165            buffer.update(cx, |buffer, _| {
1166                buffer.merge_transactions(transaction, destination)
1167            });
1168        } else if let Some(transaction) = self.history.forget(transaction) {
1169            if let Some(destination) = self.history.transaction_mut(destination) {
1170                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1171                    if let Some(destination_buffer_transaction_id) =
1172                        destination.buffer_transactions.get(&buffer_id)
1173                    {
1174                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1175                            state.buffer.update(cx, |buffer, _| {
1176                                buffer.merge_transactions(
1177                                    buffer_transaction_id,
1178                                    *destination_buffer_transaction_id,
1179                                )
1180                            });
1181                        }
1182                    } else {
1183                        destination
1184                            .buffer_transactions
1185                            .insert(buffer_id, buffer_transaction_id);
1186                    }
1187                }
1188            }
1189        }
1190    }
1191
1192    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1193        self.history.finalize_last_transaction();
1194        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1195            buffer.update(cx, |buffer, _| {
1196                buffer.finalize_last_transaction();
1197            });
1198        }
1199    }
1200
1201    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1202    where
1203        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1204    {
1205        self.history
1206            .push_transaction(buffer_transactions, Instant::now(), cx);
1207        self.history.finalize_last_transaction();
1208    }
1209
1210    pub fn group_until_transaction(
1211        &mut self,
1212        transaction_id: TransactionId,
1213        cx: &mut Context<Self>,
1214    ) {
1215        if let Some(buffer) = self.as_singleton() {
1216            buffer.update(cx, |buffer, _| {
1217                buffer.group_until_transaction(transaction_id)
1218            });
1219        } else {
1220            self.history.group_until(transaction_id);
1221        }
1222    }
1223
1224    pub fn set_active_selections(
1225        &self,
1226        selections: &[Selection<Anchor>],
1227        line_mode: bool,
1228        cursor_shape: CursorShape,
1229        cx: &mut Context<Self>,
1230    ) {
1231        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1232            Default::default();
1233        let snapshot = self.read(cx);
1234        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1235        for selection in selections {
1236            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1237            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1238
1239            cursor.seek(&Some(start_locator), Bias::Left, &());
1240            while let Some(excerpt) = cursor.item() {
1241                if excerpt.locator > *end_locator {
1242                    break;
1243                }
1244
1245                let mut start = excerpt.range.context.start;
1246                let mut end = excerpt.range.context.end;
1247                if excerpt.id == selection.start.excerpt_id {
1248                    start = selection.start.text_anchor;
1249                }
1250                if excerpt.id == selection.end.excerpt_id {
1251                    end = selection.end.text_anchor;
1252                }
1253                selections_by_buffer
1254                    .entry(excerpt.buffer_id)
1255                    .or_default()
1256                    .push(Selection {
1257                        id: selection.id,
1258                        start,
1259                        end,
1260                        reversed: selection.reversed,
1261                        goal: selection.goal,
1262                    });
1263
1264                cursor.next(&());
1265            }
1266        }
1267
1268        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1269            if !selections_by_buffer.contains_key(buffer_id) {
1270                buffer_state
1271                    .buffer
1272                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1273            }
1274        }
1275
1276        for (buffer_id, mut selections) in selections_by_buffer {
1277            self.buffers.borrow()[&buffer_id]
1278                .buffer
1279                .update(cx, |buffer, cx| {
1280                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1281                    let mut selections = selections.into_iter().peekable();
1282                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1283                        let mut selection = selections.next()?;
1284                        while let Some(next_selection) = selections.peek() {
1285                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1286                                let next_selection = selections.next().unwrap();
1287                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1288                                    selection.end = next_selection.end;
1289                                }
1290                            } else {
1291                                break;
1292                            }
1293                        }
1294                        Some(selection)
1295                    }));
1296                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1297                });
1298        }
1299    }
1300
1301    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1302        for buffer in self.buffers.borrow().values() {
1303            buffer
1304                .buffer
1305                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1306        }
1307    }
1308
1309    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1310        let mut transaction_id = None;
1311        if let Some(buffer) = self.as_singleton() {
1312            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1313        } else {
1314            while let Some(transaction) = self.history.pop_undo() {
1315                let mut undone = false;
1316                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1317                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1318                        undone |= buffer.update(cx, |buffer, cx| {
1319                            let undo_to = *buffer_transaction_id;
1320                            if let Some(entry) = buffer.peek_undo_stack() {
1321                                *buffer_transaction_id = entry.transaction_id();
1322                            }
1323                            buffer.undo_to_transaction(undo_to, cx)
1324                        });
1325                    }
1326                }
1327
1328                if undone {
1329                    transaction_id = Some(transaction.id);
1330                    break;
1331                }
1332            }
1333        }
1334
1335        if let Some(transaction_id) = transaction_id {
1336            cx.emit(Event::TransactionUndone { transaction_id });
1337        }
1338
1339        transaction_id
1340    }
1341
1342    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1343        if let Some(buffer) = self.as_singleton() {
1344            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1345        }
1346
1347        while let Some(transaction) = self.history.pop_redo() {
1348            let mut redone = false;
1349            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1350                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1351                    redone |= buffer.update(cx, |buffer, cx| {
1352                        let redo_to = *buffer_transaction_id;
1353                        if let Some(entry) = buffer.peek_redo_stack() {
1354                            *buffer_transaction_id = entry.transaction_id();
1355                        }
1356                        buffer.redo_to_transaction(redo_to, cx)
1357                    });
1358                }
1359            }
1360
1361            if redone {
1362                return Some(transaction.id);
1363            }
1364        }
1365
1366        None
1367    }
1368
1369    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1370        if let Some(buffer) = self.as_singleton() {
1371            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1372        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1373            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1374                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1375                    buffer.update(cx, |buffer, cx| {
1376                        buffer.undo_transaction(*transaction_id, cx)
1377                    });
1378                }
1379            }
1380        }
1381    }
1382
1383    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1384        if let Some(buffer) = self.as_singleton() {
1385            buffer.update(cx, |buffer, _| {
1386                buffer.forget_transaction(transaction_id);
1387            });
1388        } else if let Some(transaction) = self.history.forget(transaction_id) {
1389            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1390                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1391                    state.buffer.update(cx, |buffer, _| {
1392                        buffer.forget_transaction(buffer_transaction_id);
1393                    });
1394                }
1395            }
1396        }
1397    }
1398
1399    pub fn push_excerpts<O>(
1400        &mut self,
1401        buffer: Entity<Buffer>,
1402        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1403        cx: &mut Context<Self>,
1404    ) -> Vec<ExcerptId>
1405    where
1406        O: text::ToOffset,
1407    {
1408        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1409    }
1410
1411    pub fn push_excerpts_with_context_lines<O>(
1412        &mut self,
1413        buffer: Entity<Buffer>,
1414        ranges: Vec<Range<O>>,
1415        context_line_count: u32,
1416        cx: &mut Context<Self>,
1417    ) -> Vec<Range<Anchor>>
1418    where
1419        O: text::ToPoint + text::ToOffset,
1420    {
1421        let buffer_id = buffer.read(cx).remote_id();
1422        let buffer_snapshot = buffer.read(cx).snapshot();
1423        let (excerpt_ranges, range_counts) =
1424            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1425
1426        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1427
1428        let mut anchor_ranges = Vec::new();
1429        let mut ranges = ranges.into_iter();
1430        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1431            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1432                let start = Anchor {
1433                    buffer_id: Some(buffer_id),
1434                    excerpt_id,
1435                    text_anchor: buffer_snapshot.anchor_after(range.start),
1436                    diff_base_anchor: None,
1437                };
1438                let end = Anchor {
1439                    buffer_id: Some(buffer_id),
1440                    excerpt_id,
1441                    text_anchor: buffer_snapshot.anchor_after(range.end),
1442                    diff_base_anchor: None,
1443                };
1444                start..end
1445            }))
1446        }
1447        anchor_ranges
1448    }
1449
1450    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1451        let excerpt_id = self.buffers_by_path.get(path)?.first()?;
1452        let snapshot = self.snapshot(cx);
1453        let excerpt = snapshot.excerpt(*excerpt_id)?;
1454        Some(Anchor::in_buffer(
1455            *excerpt_id,
1456            excerpt.buffer_id,
1457            excerpt.range.context.start,
1458        ))
1459    }
1460
1461    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1462        self.buffers_by_path.keys()
1463    }
1464
1465    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1466    pub fn set_excerpts_for_path(
1467        &mut self,
1468        path: PathKey,
1469        buffer: Entity<Buffer>,
1470        ranges: Vec<Range<Point>>,
1471        context_line_count: u32,
1472        cx: &mut Context<Self>,
1473    ) -> bool {
1474        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1475
1476        let mut insert_after = self
1477            .buffers_by_path
1478            .range(..path.clone())
1479            .next_back()
1480            .map(|(_, value)| *value.last().unwrap())
1481            .unwrap_or(ExcerptId::min());
1482        let existing = self.buffers_by_path.get(&path).cloned().unwrap_or_default();
1483
1484        let (new, _) = build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1485
1486        let mut new_iter = new.into_iter().peekable();
1487        let mut existing_iter = existing.into_iter().peekable();
1488
1489        let mut new_excerpt_ids = Vec::new();
1490        let mut to_remove = Vec::new();
1491        let mut to_insert = Vec::new();
1492        let mut added_a_new_excerpt = false;
1493        let snapshot = self.snapshot(cx);
1494
1495        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1496        excerpts_cursor.next(&());
1497
1498        loop {
1499            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1500                (Some(new), Some(existing)) => (new, existing),
1501                (None, None) => break,
1502                (None, Some(_)) => {
1503                    to_remove.push(existing_iter.next().unwrap());
1504                    continue;
1505                }
1506                (Some(_), None) => {
1507                    added_a_new_excerpt = true;
1508                    to_insert.push(new_iter.next().unwrap());
1509                    continue;
1510                }
1511            };
1512            let locator = snapshot.excerpt_locator_for_id(*existing);
1513            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1514            let existing_excerpt = excerpts_cursor.item().unwrap();
1515            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1516                to_remove.push(existing_iter.next().unwrap());
1517                to_insert.push(new_iter.next().unwrap());
1518                continue;
1519            }
1520
1521            let existing_start = existing_excerpt
1522                .range
1523                .context
1524                .start
1525                .to_point(&buffer_snapshot);
1526            let existing_end = existing_excerpt
1527                .range
1528                .context
1529                .end
1530                .to_point(&buffer_snapshot);
1531
1532            if existing_end < new.context.start {
1533                to_remove.push(existing_iter.next().unwrap());
1534                continue;
1535            } else if existing_start > new.context.end {
1536                to_insert.push(new_iter.next().unwrap());
1537                continue;
1538            }
1539
1540            // maybe merge overlapping excerpts?
1541            // it's hard to distinguish between a manually expanded excerpt, and one that
1542            // got smaller because of a missing diff.
1543            if existing_start == new.context.start && existing_end == new.context.end {
1544                new_excerpt_ids.append(&mut self.insert_excerpts_after(
1545                    insert_after,
1546                    buffer.clone(),
1547                    mem::take(&mut to_insert),
1548                    cx,
1549                ));
1550                insert_after = existing_iter.next().unwrap();
1551                new_excerpt_ids.push(insert_after);
1552                new_iter.next();
1553            } else {
1554                to_remove.push(existing_iter.next().unwrap());
1555                to_insert.push(new_iter.next().unwrap());
1556            }
1557        }
1558
1559        new_excerpt_ids.append(&mut self.insert_excerpts_after(
1560            insert_after,
1561            buffer,
1562            to_insert,
1563            cx,
1564        ));
1565        self.remove_excerpts(to_remove, cx);
1566        if new_excerpt_ids.is_empty() {
1567            self.buffers_by_path.remove(&path);
1568        } else {
1569            self.buffers_by_path.insert(path, new_excerpt_ids);
1570        }
1571
1572        added_a_new_excerpt
1573    }
1574
1575    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1576        self.buffers_by_path.keys().cloned()
1577    }
1578
1579    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1580        if let Some(to_remove) = self.buffers_by_path.remove(&path) {
1581            self.remove_excerpts(to_remove, cx)
1582        }
1583    }
1584
1585    pub fn push_multiple_excerpts_with_context_lines(
1586        &self,
1587        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1588        context_line_count: u32,
1589        cx: &mut Context<Self>,
1590    ) -> Task<Vec<Range<Anchor>>> {
1591        use futures::StreamExt;
1592
1593        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1594
1595        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1596
1597        for (buffer, ranges) in buffers_with_ranges {
1598            let (buffer_id, buffer_snapshot) =
1599                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1600
1601            buffer_ids.push(buffer_id);
1602
1603            cx.background_spawn({
1604                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1605
1606                async move {
1607                    let (excerpt_ranges, counts) =
1608                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1609                    excerpt_ranges_tx
1610                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1611                        .await
1612                        .ok();
1613                }
1614            })
1615            .detach()
1616        }
1617
1618        cx.spawn(move |this, mut cx| async move {
1619            let mut results_by_buffer_id = HashMap::default();
1620            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1621                excerpt_ranges_rx.next().await
1622            {
1623                results_by_buffer_id
1624                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1625            }
1626
1627            let mut multi_buffer_ranges = Vec::default();
1628            'outer: for buffer_id in buffer_ids {
1629                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1630                    results_by_buffer_id.remove(&buffer_id)
1631                else {
1632                    continue;
1633                };
1634
1635                let mut ranges = ranges.into_iter();
1636                let mut range_counts = range_counts.into_iter();
1637                for excerpt_ranges in excerpt_ranges.chunks(100) {
1638                    let excerpt_ids = match this.update(&mut cx, |this, cx| {
1639                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1640                    }) {
1641                        Ok(excerpt_ids) => excerpt_ids,
1642                        Err(_) => continue 'outer,
1643                    };
1644
1645                    for (excerpt_id, range_count) in
1646                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1647                    {
1648                        for range in ranges.by_ref().take(range_count) {
1649                            let start = Anchor {
1650                                buffer_id: Some(buffer_id),
1651                                excerpt_id,
1652                                text_anchor: range.start,
1653                                diff_base_anchor: None,
1654                            };
1655                            let end = Anchor {
1656                                buffer_id: Some(buffer_id),
1657                                excerpt_id,
1658                                text_anchor: range.end,
1659                                diff_base_anchor: None,
1660                            };
1661                            multi_buffer_ranges.push(start..end);
1662                        }
1663                    }
1664                }
1665            }
1666
1667            multi_buffer_ranges
1668        })
1669    }
1670
1671    pub fn insert_excerpts_after<O>(
1672        &mut self,
1673        prev_excerpt_id: ExcerptId,
1674        buffer: Entity<Buffer>,
1675        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1676        cx: &mut Context<Self>,
1677    ) -> Vec<ExcerptId>
1678    where
1679        O: text::ToOffset,
1680    {
1681        let mut ids = Vec::new();
1682        let mut next_excerpt_id =
1683            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1684                last_entry.id.0 + 1
1685            } else {
1686                1
1687            };
1688        self.insert_excerpts_with_ids_after(
1689            prev_excerpt_id,
1690            buffer,
1691            ranges.into_iter().map(|range| {
1692                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1693                ids.push(id);
1694                (id, range)
1695            }),
1696            cx,
1697        );
1698        ids
1699    }
1700
1701    pub fn insert_excerpts_with_ids_after<O>(
1702        &mut self,
1703        prev_excerpt_id: ExcerptId,
1704        buffer: Entity<Buffer>,
1705        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1706        cx: &mut Context<Self>,
1707    ) where
1708        O: text::ToOffset,
1709    {
1710        assert_eq!(self.history.transaction_depth, 0);
1711        let mut ranges = ranges.into_iter().peekable();
1712        if ranges.peek().is_none() {
1713            return Default::default();
1714        }
1715
1716        self.sync(cx);
1717
1718        let buffer_id = buffer.read(cx).remote_id();
1719        let buffer_snapshot = buffer.read(cx).snapshot();
1720
1721        let mut buffers = self.buffers.borrow_mut();
1722        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1723            last_version: buffer_snapshot.version().clone(),
1724            last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1725            excerpts: Default::default(),
1726            _subscriptions: [
1727                cx.observe(&buffer, |_, _, cx| cx.notify()),
1728                cx.subscribe(&buffer, Self::on_buffer_event),
1729            ],
1730            buffer: buffer.clone(),
1731        });
1732
1733        let mut snapshot = self.snapshot.borrow_mut();
1734
1735        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1736        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1737        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1738        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1739        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1740
1741        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1742        new_excerpts.update_last(
1743            |excerpt| {
1744                excerpt.has_trailing_newline = true;
1745            },
1746            &(),
1747        );
1748
1749        let next_locator = if let Some(excerpt) = cursor.item() {
1750            excerpt.locator.clone()
1751        } else {
1752            Locator::max()
1753        };
1754
1755        let mut excerpts = Vec::new();
1756        while let Some((id, range)) = ranges.next() {
1757            let locator = Locator::between(&prev_locator, &next_locator);
1758            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1759                buffer_state.excerpts.insert(ix, locator.clone());
1760            }
1761            let range = ExcerptRange {
1762                context: buffer_snapshot.anchor_before(&range.context.start)
1763                    ..buffer_snapshot.anchor_after(&range.context.end),
1764                primary: range.primary.map(|primary| {
1765                    buffer_snapshot.anchor_before(&primary.start)
1766                        ..buffer_snapshot.anchor_after(&primary.end)
1767                }),
1768            };
1769            excerpts.push((id, range.clone()));
1770            let excerpt = Excerpt::new(
1771                id,
1772                locator.clone(),
1773                buffer_id,
1774                buffer_snapshot.clone(),
1775                range,
1776                ranges.peek().is_some() || cursor.item().is_some(),
1777            );
1778            new_excerpts.push(excerpt, &());
1779            prev_locator = locator.clone();
1780
1781            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1782                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1783            }
1784            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1785        }
1786
1787        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1788
1789        let suffix = cursor.suffix(&());
1790        let changed_trailing_excerpt = suffix.is_empty();
1791        new_excerpts.append(suffix, &());
1792        drop(cursor);
1793        snapshot.excerpts = new_excerpts;
1794        snapshot.excerpt_ids = new_excerpt_ids;
1795        if changed_trailing_excerpt {
1796            snapshot.trailing_excerpt_update_count += 1;
1797        }
1798
1799        self.sync_diff_transforms(
1800            &mut snapshot,
1801            vec![Edit {
1802                old: edit_start..edit_start,
1803                new: edit_start..edit_end,
1804            }],
1805            DiffChangeKind::BufferEdited,
1806        );
1807        cx.emit(Event::Edited {
1808            singleton_buffer_edited: false,
1809            edited_buffer: None,
1810        });
1811        cx.emit(Event::ExcerptsAdded {
1812            buffer,
1813            predecessor: prev_excerpt_id,
1814            excerpts,
1815        });
1816        cx.notify();
1817    }
1818
1819    pub fn clear(&mut self, cx: &mut Context<Self>) {
1820        self.sync(cx);
1821        let ids = self.excerpt_ids();
1822        self.buffers.borrow_mut().clear();
1823        let mut snapshot = self.snapshot.borrow_mut();
1824        let start = ExcerptOffset::new(0);
1825        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
1826        snapshot.excerpts = Default::default();
1827        snapshot.trailing_excerpt_update_count += 1;
1828        snapshot.is_dirty = false;
1829        snapshot.has_deleted_file = false;
1830        snapshot.has_conflict = false;
1831
1832        self.sync_diff_transforms(
1833            &mut snapshot,
1834            vec![Edit {
1835                old: start..prev_len,
1836                new: start..start,
1837            }],
1838            DiffChangeKind::BufferEdited,
1839        );
1840        cx.emit(Event::Edited {
1841            singleton_buffer_edited: false,
1842            edited_buffer: None,
1843        });
1844        cx.emit(Event::ExcerptsRemoved { ids });
1845        cx.notify();
1846    }
1847
1848    pub fn excerpts_for_buffer(
1849        &self,
1850        buffer_id: BufferId,
1851        cx: &App,
1852    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1853        let mut excerpts = Vec::new();
1854        let snapshot = self.read(cx);
1855        let buffers = self.buffers.borrow();
1856        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1857        for locator in buffers
1858            .get(&buffer_id)
1859            .map(|state| &state.excerpts)
1860            .into_iter()
1861            .flatten()
1862        {
1863            cursor.seek_forward(&Some(locator), Bias::Left, &());
1864            if let Some(excerpt) = cursor.item() {
1865                if excerpt.locator == *locator {
1866                    excerpts.push((excerpt.id, excerpt.range.clone()));
1867                }
1868            }
1869        }
1870
1871        excerpts
1872    }
1873
1874    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1875        let snapshot = self.read(cx);
1876        let buffers = self.buffers.borrow();
1877        let mut excerpts = snapshot
1878            .excerpts
1879            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
1880        let mut diff_transforms = snapshot
1881            .diff_transforms
1882            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
1883        diff_transforms.next(&());
1884        let locators = buffers
1885            .get(&buffer_id)
1886            .into_iter()
1887            .flat_map(|state| &state.excerpts);
1888        let mut result = Vec::new();
1889        for locator in locators {
1890            excerpts.seek_forward(&Some(locator), Bias::Left, &());
1891            if let Some(excerpt) = excerpts.item() {
1892                if excerpt.locator == *locator {
1893                    let excerpt_start = excerpts.start().1.clone();
1894                    let excerpt_end =
1895                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1896
1897                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
1898                    let overshoot = excerpt_start.0 - diff_transforms.start().0 .0;
1899                    let start = diff_transforms.start().1 .0 + overshoot;
1900
1901                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
1902                    let overshoot = excerpt_end.0 - diff_transforms.start().0 .0;
1903                    let end = diff_transforms.start().1 .0 + overshoot;
1904
1905                    result.push(start..end)
1906                }
1907            }
1908        }
1909        result
1910    }
1911
1912    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1913        self.snapshot
1914            .borrow()
1915            .excerpts
1916            .iter()
1917            .map(|entry| entry.buffer_id)
1918            .collect()
1919    }
1920
1921    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1922        self.snapshot
1923            .borrow()
1924            .excerpts
1925            .iter()
1926            .map(|entry| entry.id)
1927            .collect()
1928    }
1929
1930    pub fn excerpt_containing(
1931        &self,
1932        position: impl ToOffset,
1933        cx: &App,
1934    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1935        let snapshot = self.read(cx);
1936        let offset = position.to_offset(&snapshot);
1937
1938        let mut cursor = snapshot.cursor::<usize>();
1939        cursor.seek(&offset);
1940        cursor
1941            .excerpt()
1942            .or_else(|| snapshot.excerpts.last())
1943            .map(|excerpt| {
1944                (
1945                    excerpt.id,
1946                    self.buffers
1947                        .borrow()
1948                        .get(&excerpt.buffer_id)
1949                        .unwrap()
1950                        .buffer
1951                        .clone(),
1952                    excerpt.range.context.clone(),
1953                )
1954            })
1955    }
1956
1957    // If point is at the end of the buffer, the last excerpt is returned
1958    pub fn point_to_buffer_offset<T: ToOffset>(
1959        &self,
1960        point: T,
1961        cx: &App,
1962    ) -> Option<(Entity<Buffer>, usize)> {
1963        let snapshot = self.read(cx);
1964        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1965        Some((
1966            self.buffers
1967                .borrow()
1968                .get(&buffer.remote_id())?
1969                .buffer
1970                .clone(),
1971            offset,
1972        ))
1973    }
1974
1975    // If point is at the end of the buffer, the last excerpt is returned
1976    pub fn point_to_buffer_point<T: ToPoint>(
1977        &self,
1978        point: T,
1979        cx: &App,
1980    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1981        let snapshot = self.read(cx);
1982        let point = point.to_point(&snapshot);
1983        let mut cursor = snapshot.cursor::<Point>();
1984        cursor.seek(&point);
1985
1986        cursor.region().and_then(|region| {
1987            if !region.is_main_buffer {
1988                return None;
1989            }
1990
1991            let overshoot = point - region.range.start;
1992            let buffer_point = region.buffer_range.start + overshoot;
1993            let buffer = self.buffers.borrow()[&region.buffer.remote_id()]
1994                .buffer
1995                .clone();
1996            Some((buffer, buffer_point, region.excerpt.id))
1997        })
1998    }
1999
2000    pub fn buffer_point_to_anchor(
2001        &self,
2002        buffer: &Entity<Buffer>,
2003        point: Point,
2004        cx: &App,
2005    ) -> Option<Anchor> {
2006        let mut found = None;
2007        let snapshot = buffer.read(cx).snapshot();
2008        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2009            let start = range.context.start.to_point(&snapshot);
2010            let end = range.context.end.to_point(&snapshot);
2011            if start <= point && point < end {
2012                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2013                break;
2014            }
2015            if point < start {
2016                found = Some((start, excerpt_id));
2017            }
2018            if point > end {
2019                found = Some((end, excerpt_id));
2020            }
2021        }
2022
2023        found.map(|(point, excerpt_id)| {
2024            let text_anchor = snapshot.anchor_after(point);
2025            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2026        })
2027    }
2028
2029    pub fn remove_excerpts(
2030        &mut self,
2031        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2032        cx: &mut Context<Self>,
2033    ) {
2034        self.sync(cx);
2035        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2036        if ids.is_empty() {
2037            return;
2038        }
2039
2040        let mut buffers = self.buffers.borrow_mut();
2041        let mut snapshot = self.snapshot.borrow_mut();
2042        let mut new_excerpts = SumTree::default();
2043        let mut cursor = snapshot
2044            .excerpts
2045            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2046        let mut edits = Vec::new();
2047        let mut excerpt_ids = ids.iter().copied().peekable();
2048
2049        while let Some(excerpt_id) = excerpt_ids.next() {
2050            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2051            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2052            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2053
2054            if let Some(mut excerpt) = cursor.item() {
2055                if excerpt.id != excerpt_id {
2056                    continue;
2057                }
2058                let mut old_start = cursor.start().1;
2059
2060                // Skip over the removed excerpt.
2061                'remove_excerpts: loop {
2062                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2063                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2064                        if buffer_state.excerpts.is_empty() {
2065                            log::debug!(
2066                                "removing buffer and diff for buffer {}",
2067                                excerpt.buffer_id
2068                            );
2069                            buffers.remove(&excerpt.buffer_id);
2070                            self.diffs.remove(&excerpt.buffer_id);
2071                        }
2072                    }
2073                    cursor.next(&());
2074
2075                    // Skip over any subsequent excerpts that are also removed.
2076                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2077                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2078                        if let Some(next_excerpt) = cursor.item() {
2079                            if next_excerpt.locator == *next_locator {
2080                                excerpt_ids.next();
2081                                excerpt = next_excerpt;
2082                                continue 'remove_excerpts;
2083                            }
2084                        }
2085                    }
2086
2087                    break;
2088                }
2089
2090                // When removing the last excerpt, remove the trailing newline from
2091                // the previous excerpt.
2092                if cursor.item().is_none() && old_start.value > 0 {
2093                    old_start.value -= 1;
2094                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2095                }
2096
2097                // Push an edit for the removal of this run of excerpts.
2098                let old_end = cursor.start().1;
2099                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2100                edits.push(Edit {
2101                    old: old_start..old_end,
2102                    new: new_start..new_start,
2103                });
2104            }
2105        }
2106        let suffix = cursor.suffix(&());
2107        let changed_trailing_excerpt = suffix.is_empty();
2108        new_excerpts.append(suffix, &());
2109        drop(cursor);
2110        snapshot.excerpts = new_excerpts;
2111
2112        if changed_trailing_excerpt {
2113            snapshot.trailing_excerpt_update_count += 1;
2114        }
2115
2116        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2117        cx.emit(Event::Edited {
2118            singleton_buffer_edited: false,
2119            edited_buffer: None,
2120        });
2121        cx.emit(Event::ExcerptsRemoved { ids });
2122        cx.notify();
2123    }
2124
2125    pub fn wait_for_anchors<'a>(
2126        &self,
2127        anchors: impl 'a + Iterator<Item = Anchor>,
2128        cx: &mut Context<Self>,
2129    ) -> impl 'static + Future<Output = Result<()>> {
2130        let borrow = self.buffers.borrow();
2131        let mut error = None;
2132        let mut futures = Vec::new();
2133        for anchor in anchors {
2134            if let Some(buffer_id) = anchor.buffer_id {
2135                if let Some(buffer) = borrow.get(&buffer_id) {
2136                    buffer.buffer.update(cx, |buffer, _| {
2137                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2138                    });
2139                } else {
2140                    error = Some(anyhow!(
2141                        "buffer {buffer_id} is not part of this multi-buffer"
2142                    ));
2143                    break;
2144                }
2145            }
2146        }
2147        async move {
2148            if let Some(error) = error {
2149                Err(error)?;
2150            }
2151            for future in futures {
2152                future.await?;
2153            }
2154            Ok(())
2155        }
2156    }
2157
2158    pub fn text_anchor_for_position<T: ToOffset>(
2159        &self,
2160        position: T,
2161        cx: &App,
2162    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2163        let snapshot = self.read(cx);
2164        let anchor = snapshot.anchor_before(position);
2165        let buffer = self
2166            .buffers
2167            .borrow()
2168            .get(&anchor.buffer_id?)?
2169            .buffer
2170            .clone();
2171        Some((buffer, anchor.text_anchor))
2172    }
2173
2174    fn on_buffer_event(
2175        &mut self,
2176        buffer: Entity<Buffer>,
2177        event: &language::BufferEvent,
2178        cx: &mut Context<Self>,
2179    ) {
2180        cx.emit(match event {
2181            language::BufferEvent::Edited => Event::Edited {
2182                singleton_buffer_edited: true,
2183                edited_buffer: Some(buffer.clone()),
2184            },
2185            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2186            language::BufferEvent::Saved => Event::Saved,
2187            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2188            language::BufferEvent::Reloaded => Event::Reloaded,
2189            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2190            language::BufferEvent::LanguageChanged => {
2191                Event::LanguageChanged(buffer.read(cx).remote_id())
2192            }
2193            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2194            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2195            language::BufferEvent::Closed => Event::Closed,
2196            language::BufferEvent::Discarded => Event::Discarded,
2197            language::BufferEvent::CapabilityChanged => {
2198                self.capability = buffer.read(cx).capability();
2199                Event::CapabilityChanged
2200            }
2201            language::BufferEvent::Operation { .. } => return,
2202        });
2203    }
2204
2205    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2206        self.sync(cx);
2207        let mut snapshot = self.snapshot.borrow_mut();
2208        let diff = diff.read(cx);
2209        let buffer_id = diff.buffer_id;
2210        let diff = diff.snapshot(cx);
2211        snapshot.diffs.insert(buffer_id, diff);
2212    }
2213
2214    fn buffer_diff_changed(
2215        &mut self,
2216        diff: Entity<BufferDiff>,
2217        range: Range<text::Anchor>,
2218        cx: &mut Context<Self>,
2219    ) {
2220        self.sync(cx);
2221
2222        let diff = diff.read(cx);
2223        let buffer_id = diff.buffer_id;
2224        let buffers = self.buffers.borrow();
2225        let Some(buffer_state) = buffers.get(&buffer_id) else {
2226            return;
2227        };
2228
2229        let buffer = buffer_state.buffer.read(cx);
2230        let diff_change_range = range.to_offset(buffer);
2231
2232        let new_diff = diff.snapshot(cx);
2233        let mut snapshot = self.snapshot.borrow_mut();
2234        let base_text_changed = snapshot
2235            .diffs
2236            .get(&buffer_id)
2237            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2238
2239        snapshot.diffs.insert(buffer_id, new_diff);
2240
2241        let mut excerpt_edits = Vec::new();
2242        for locator in &buffer_state.excerpts {
2243            let mut cursor = snapshot
2244                .excerpts
2245                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2246            cursor.seek_forward(&Some(locator), Bias::Left, &());
2247            if let Some(excerpt) = cursor.item() {
2248                if excerpt.locator == *locator {
2249                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2250                    if diff_change_range.end < excerpt_buffer_range.start
2251                        || diff_change_range.start > excerpt_buffer_range.end
2252                    {
2253                        continue;
2254                    }
2255                    let excerpt_start = cursor.start().1;
2256                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2257                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2258                        diff_change_range
2259                            .start
2260                            .saturating_sub(excerpt_buffer_range.start),
2261                    );
2262                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2263                        diff_change_range
2264                            .end
2265                            .saturating_sub(excerpt_buffer_range.start),
2266                    );
2267                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2268                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2269                    excerpt_edits.push(Edit {
2270                        old: edit_start..edit_end,
2271                        new: edit_start..edit_end,
2272                    });
2273                }
2274            }
2275        }
2276
2277        self.sync_diff_transforms(
2278            &mut snapshot,
2279            excerpt_edits,
2280            DiffChangeKind::DiffUpdated {
2281                base_changed: base_text_changed,
2282            },
2283        );
2284        cx.emit(Event::Edited {
2285            singleton_buffer_edited: false,
2286            edited_buffer: None,
2287        });
2288    }
2289
2290    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2291        self.buffers
2292            .borrow()
2293            .values()
2294            .map(|state| state.buffer.clone())
2295            .collect()
2296    }
2297
2298    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2299        self.buffers
2300            .borrow()
2301            .get(&buffer_id)
2302            .map(|state| state.buffer.clone())
2303    }
2304
2305    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2306        self.point_to_buffer_offset(point, cx)
2307            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2308    }
2309
2310    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2311        let buffer_id = self
2312            .snapshot
2313            .borrow()
2314            .excerpts
2315            .first()
2316            .map(|excerpt| excerpt.buffer.remote_id());
2317        buffer_id
2318            .and_then(|buffer_id| self.buffer(buffer_id))
2319            .map(|buffer| {
2320                let buffer = buffer.read(cx);
2321                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2322            })
2323            .unwrap_or_else(move || self.language_settings_at(0, cx))
2324    }
2325
2326    pub fn language_settings_at<'a, T: ToOffset>(
2327        &'a self,
2328        point: T,
2329        cx: &'a App,
2330    ) -> Cow<'a, LanguageSettings> {
2331        let mut language = None;
2332        let mut file = None;
2333        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2334            let buffer = buffer.read(cx);
2335            language = buffer.language_at(offset);
2336            file = buffer.file();
2337        }
2338        language_settings(language.map(|l| l.name()), file, cx)
2339    }
2340
2341    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2342        self.buffers
2343            .borrow()
2344            .values()
2345            .for_each(|state| f(&state.buffer))
2346    }
2347
2348    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2349        if let Some(title) = self.title.as_ref() {
2350            return title.into();
2351        }
2352
2353        if let Some(buffer) = self.as_singleton() {
2354            if let Some(file) = buffer.read(cx).file() {
2355                return file.file_name(cx).to_string_lossy();
2356            }
2357        }
2358
2359        "untitled".into()
2360    }
2361
2362    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2363        self.title = Some(title);
2364        cx.notify();
2365    }
2366
2367    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2368    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2369        for buffer_state in self.buffers.borrow().values() {
2370            buffer_state
2371                .buffer
2372                .update(cx, |buffer, _cx| buffer.refresh_preview());
2373        }
2374    }
2375
2376    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2377    pub fn preserve_preview(&self, cx: &App) -> bool {
2378        self.buffers
2379            .borrow()
2380            .values()
2381            .all(|state| state.buffer.read(cx).preserve_preview())
2382    }
2383
2384    #[cfg(any(test, feature = "test-support"))]
2385    pub fn is_parsing(&self, cx: &App) -> bool {
2386        self.as_singleton().unwrap().read(cx).is_parsing()
2387    }
2388
2389    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2390        let buffer_id = diff.read(cx).buffer_id;
2391        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2392        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2393    }
2394
2395    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2396        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2397    }
2398
2399    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2400        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2401    }
2402
2403    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2404        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2405    }
2406
2407    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2408        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2409        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2410    }
2411
2412    pub fn all_diff_hunks_expanded(&self) -> bool {
2413        self.snapshot.borrow().all_diff_hunks_expanded
2414    }
2415
2416    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2417        self.read(cx)
2418            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2419            .nth(1)
2420            .is_some()
2421    }
2422
2423    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2424        let snapshot = self.read(cx);
2425        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2426        let offset_range = range.to_offset(&snapshot);
2427        cursor.seek(&offset_range.start, Bias::Left, &());
2428        while let Some(item) = cursor.item() {
2429            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2430                break;
2431            }
2432            if item.hunk_info().is_some() {
2433                return true;
2434            }
2435            cursor.next(&());
2436        }
2437        false
2438    }
2439
2440    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2441        let snapshot = self.read(cx);
2442        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2443        for range in ranges {
2444            let range = range.to_point(&snapshot);
2445            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2446            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2447            let start = start.saturating_sub(1);
2448            let end = snapshot.len().min(end + 1);
2449            cursor.seek(&start, Bias::Right, &());
2450            while let Some(item) = cursor.item() {
2451                if *cursor.start() >= end {
2452                    break;
2453                }
2454                if item.hunk_info().is_some() {
2455                    return true;
2456                }
2457                cursor.next(&());
2458            }
2459        }
2460        false
2461    }
2462
2463    pub fn expand_or_collapse_diff_hunks_inner(
2464        &mut self,
2465        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2466        expand: bool,
2467        cx: &mut Context<Self>,
2468    ) {
2469        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2470            return;
2471        }
2472        self.sync(cx);
2473        let mut snapshot = self.snapshot.borrow_mut();
2474        let mut excerpt_edits = Vec::new();
2475        for (range, end_excerpt_id) in ranges {
2476            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2477                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2478                    continue;
2479                }
2480                let start = Anchor::in_buffer(
2481                    diff_hunk.excerpt_id,
2482                    diff_hunk.buffer_id,
2483                    diff_hunk.buffer_range.start,
2484                );
2485                let end = Anchor::in_buffer(
2486                    diff_hunk.excerpt_id,
2487                    diff_hunk.buffer_id,
2488                    diff_hunk.buffer_range.end,
2489                );
2490                let start = snapshot.excerpt_offset_for_anchor(&start);
2491                let end = snapshot.excerpt_offset_for_anchor(&end);
2492                excerpt_edits.push(text::Edit {
2493                    old: start..end,
2494                    new: start..end,
2495                });
2496            }
2497        }
2498
2499        self.sync_diff_transforms(
2500            &mut snapshot,
2501            excerpt_edits,
2502            DiffChangeKind::ExpandOrCollapseHunks { expand },
2503        );
2504        cx.emit(Event::DiffHunksToggled);
2505        cx.emit(Event::Edited {
2506            singleton_buffer_edited: false,
2507            edited_buffer: None,
2508        });
2509    }
2510
2511    pub fn expand_or_collapse_diff_hunks(
2512        &mut self,
2513        ranges: Vec<Range<Anchor>>,
2514        expand: bool,
2515        cx: &mut Context<Self>,
2516    ) {
2517        let snapshot = self.snapshot.borrow().clone();
2518        let ranges = ranges.iter().map(move |range| {
2519            let end_excerpt_id = range.end.excerpt_id;
2520            let range = range.to_point(&snapshot);
2521            let mut peek_end = range.end;
2522            if range.end.row < snapshot.max_row().0 {
2523                peek_end = Point::new(range.end.row + 1, 0);
2524            };
2525            (range.start..peek_end, end_excerpt_id)
2526        });
2527        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2528    }
2529
2530    pub fn resize_excerpt(
2531        &mut self,
2532        id: ExcerptId,
2533        range: Range<text::Anchor>,
2534        cx: &mut Context<Self>,
2535    ) {
2536        self.sync(cx);
2537
2538        let mut snapshot = self.snapshot.borrow_mut();
2539        let locator = snapshot.excerpt_locator_for_id(id);
2540        let mut new_excerpts = SumTree::default();
2541        let mut cursor = snapshot
2542            .excerpts
2543            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2544        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2545
2546        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2547        new_excerpts.append(prefix, &());
2548
2549        let mut excerpt = cursor.item().unwrap().clone();
2550        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2551
2552        excerpt.range.context.start = range.start;
2553        excerpt.range.context.end = range.end;
2554        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2555
2556        excerpt.text_summary = excerpt
2557            .buffer
2558            .text_summary_for_range(excerpt.range.context.clone());
2559
2560        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2561        let old_start_offset = cursor.start().1;
2562        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2563        let edit = Edit {
2564            old: old_start_offset..old_start_offset + old_text_len,
2565            new: new_start_offset..new_start_offset + new_text_len,
2566        };
2567
2568        if let Some(last_edit) = edits.last_mut() {
2569            if last_edit.old.end == edit.old.start {
2570                last_edit.old.end = edit.old.end;
2571                last_edit.new.end = edit.new.end;
2572            } else {
2573                edits.push(edit);
2574            }
2575        } else {
2576            edits.push(edit);
2577        }
2578
2579        new_excerpts.push(excerpt, &());
2580
2581        cursor.next(&());
2582
2583        new_excerpts.append(cursor.suffix(&()), &());
2584
2585        drop(cursor);
2586        snapshot.excerpts = new_excerpts;
2587
2588        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2589        cx.emit(Event::Edited {
2590            singleton_buffer_edited: false,
2591            edited_buffer: None,
2592        });
2593        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2594        cx.notify();
2595    }
2596
2597    pub fn expand_excerpts(
2598        &mut self,
2599        ids: impl IntoIterator<Item = ExcerptId>,
2600        line_count: u32,
2601        direction: ExpandExcerptDirection,
2602        cx: &mut Context<Self>,
2603    ) {
2604        if line_count == 0 {
2605            return;
2606        }
2607        self.sync(cx);
2608        let mut snapshot = self.snapshot.borrow_mut();
2609
2610        let ids = ids.into_iter().collect::<Vec<_>>();
2611        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2612        let mut new_excerpts = SumTree::default();
2613        let mut cursor = snapshot
2614            .excerpts
2615            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2616        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2617
2618        for locator in &locators {
2619            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2620            new_excerpts.append(prefix, &());
2621
2622            let mut excerpt = cursor.item().unwrap().clone();
2623            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2624
2625            let up_line_count = if direction.should_expand_up() {
2626                line_count
2627            } else {
2628                0
2629            };
2630
2631            let start_row = excerpt
2632                .range
2633                .context
2634                .start
2635                .to_point(&excerpt.buffer)
2636                .row
2637                .saturating_sub(up_line_count);
2638            let start_point = Point::new(start_row, 0);
2639            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2640
2641            let down_line_count = if direction.should_expand_down() {
2642                line_count
2643            } else {
2644                0
2645            };
2646
2647            let mut end_point = excerpt.buffer.clip_point(
2648                excerpt.range.context.end.to_point(&excerpt.buffer)
2649                    + Point::new(down_line_count, 0),
2650                Bias::Left,
2651            );
2652            end_point.column = excerpt.buffer.line_len(end_point.row);
2653            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2654            excerpt.max_buffer_row = end_point.row;
2655
2656            excerpt.text_summary = excerpt
2657                .buffer
2658                .text_summary_for_range(excerpt.range.context.clone());
2659
2660            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2661            let old_start_offset = cursor.start().1;
2662            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2663            let edit = Edit {
2664                old: old_start_offset..old_start_offset + old_text_len,
2665                new: new_start_offset..new_start_offset + new_text_len,
2666            };
2667
2668            if let Some(last_edit) = edits.last_mut() {
2669                if last_edit.old.end == edit.old.start {
2670                    last_edit.old.end = edit.old.end;
2671                    last_edit.new.end = edit.new.end;
2672                } else {
2673                    edits.push(edit);
2674                }
2675            } else {
2676                edits.push(edit);
2677            }
2678
2679            new_excerpts.push(excerpt, &());
2680
2681            cursor.next(&());
2682        }
2683
2684        new_excerpts.append(cursor.suffix(&()), &());
2685
2686        drop(cursor);
2687        snapshot.excerpts = new_excerpts;
2688
2689        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2690        cx.emit(Event::Edited {
2691            singleton_buffer_edited: false,
2692            edited_buffer: None,
2693        });
2694        cx.emit(Event::ExcerptsExpanded { ids });
2695        cx.notify();
2696    }
2697
2698    fn sync(&self, cx: &App) {
2699        let mut snapshot = self.snapshot.borrow_mut();
2700        let mut excerpts_to_edit = Vec::new();
2701        let mut non_text_state_updated = false;
2702        let mut is_dirty = false;
2703        let mut has_deleted_file = false;
2704        let mut has_conflict = false;
2705        let mut edited = false;
2706        let mut buffers = self.buffers.borrow_mut();
2707        for buffer_state in buffers.values_mut() {
2708            let buffer = buffer_state.buffer.read(cx);
2709            let version = buffer.version();
2710            let non_text_state_update_count = buffer.non_text_state_update_count();
2711
2712            let buffer_edited = version.changed_since(&buffer_state.last_version);
2713            let buffer_non_text_state_updated =
2714                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2715            if buffer_edited || buffer_non_text_state_updated {
2716                buffer_state.last_version = version;
2717                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2718                excerpts_to_edit.extend(
2719                    buffer_state
2720                        .excerpts
2721                        .iter()
2722                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2723                );
2724            }
2725
2726            edited |= buffer_edited;
2727            non_text_state_updated |= buffer_non_text_state_updated;
2728            is_dirty |= buffer.is_dirty();
2729            has_deleted_file |= buffer
2730                .file()
2731                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2732            has_conflict |= buffer.has_conflict();
2733        }
2734        if edited {
2735            snapshot.edit_count += 1;
2736        }
2737        if non_text_state_updated {
2738            snapshot.non_text_state_update_count += 1;
2739        }
2740        snapshot.is_dirty = is_dirty;
2741        snapshot.has_deleted_file = has_deleted_file;
2742        snapshot.has_conflict = has_conflict;
2743
2744        snapshot.diffs.retain(|_, _| false);
2745        for (id, diff) in self.diffs.iter() {
2746            snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2747        }
2748
2749        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2750
2751        let mut edits = Vec::new();
2752        let mut new_excerpts = SumTree::default();
2753        let mut cursor = snapshot
2754            .excerpts
2755            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2756
2757        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2758            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2759            let old_excerpt = cursor.item().unwrap();
2760            let buffer = buffer.read(cx);
2761            let buffer_id = buffer.remote_id();
2762
2763            let mut new_excerpt;
2764            if buffer_edited {
2765                edits.extend(
2766                    buffer
2767                        .edits_since_in_range::<usize>(
2768                            old_excerpt.buffer.version(),
2769                            old_excerpt.range.context.clone(),
2770                        )
2771                        .map(|edit| {
2772                            let excerpt_old_start = cursor.start().1;
2773                            let excerpt_new_start =
2774                                ExcerptOffset::new(new_excerpts.summary().text.len);
2775                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2776                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2777                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2778                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2779                            Edit {
2780                                old: old_start..old_end,
2781                                new: new_start..new_end,
2782                            }
2783                        }),
2784                );
2785
2786                new_excerpt = Excerpt::new(
2787                    old_excerpt.id,
2788                    locator.clone(),
2789                    buffer_id,
2790                    buffer.snapshot(),
2791                    old_excerpt.range.clone(),
2792                    old_excerpt.has_trailing_newline,
2793                );
2794            } else {
2795                new_excerpt = old_excerpt.clone();
2796                new_excerpt.buffer = buffer.snapshot();
2797            }
2798
2799            new_excerpts.push(new_excerpt, &());
2800            cursor.next(&());
2801        }
2802        new_excerpts.append(cursor.suffix(&()), &());
2803
2804        drop(cursor);
2805        snapshot.excerpts = new_excerpts;
2806
2807        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2808    }
2809
2810    fn sync_diff_transforms(
2811        &self,
2812        snapshot: &mut MultiBufferSnapshot,
2813        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2814        change_kind: DiffChangeKind,
2815    ) {
2816        if excerpt_edits.is_empty() {
2817            return;
2818        }
2819
2820        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
2821        let mut old_diff_transforms = snapshot
2822            .diff_transforms
2823            .cursor::<(ExcerptOffset, usize)>(&());
2824        let mut new_diff_transforms = SumTree::default();
2825        let mut old_expanded_hunks = HashSet::default();
2826        let mut output_edits = Vec::new();
2827        let mut output_delta = 0_isize;
2828        let mut at_transform_boundary = true;
2829        let mut end_of_current_insert = None;
2830
2831        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2832        while let Some(edit) = excerpt_edits.next() {
2833            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
2834            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2835                excerpts.prev(&());
2836            }
2837
2838            // Keep any transforms that are before the edit.
2839            if at_transform_boundary {
2840                at_transform_boundary = false;
2841                let transforms_before_edit =
2842                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
2843                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2844                if let Some(transform) = old_diff_transforms.item() {
2845                    if old_diff_transforms.end(&()).0 == edit.old.start
2846                        && old_diff_transforms.start().0 < edit.old.start
2847                    {
2848                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
2849                        old_diff_transforms.next(&());
2850                    }
2851                }
2852            }
2853
2854            // Compute the start of the edit in output coordinates.
2855            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2856            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2857            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2858
2859            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
2860                &edit,
2861                &mut excerpts,
2862                &mut old_diff_transforms,
2863                &mut new_diff_transforms,
2864                &mut end_of_current_insert,
2865                &mut old_expanded_hunks,
2866                &snapshot,
2867                change_kind,
2868            );
2869
2870            // Compute the end of the edit in output coordinates.
2871            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2872            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2873            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2874            let edit_new_end =
2875                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2876            let output_edit = Edit {
2877                old: edit_old_start..edit_old_end,
2878                new: edit_new_start..edit_new_end,
2879            };
2880
2881            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2882            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2883            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2884                output_edits.push(output_edit);
2885            }
2886
2887            // If this is the last edit that intersects the current diff transform,
2888            // then recreate the content up to the end of this transform, to prepare
2889            // for reusing additional slices of the old transforms.
2890            if excerpt_edits.peek().map_or(true, |next_edit| {
2891                next_edit.old.start >= old_diff_transforms.end(&()).0
2892            }) {
2893                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2894                    && match old_diff_transforms.item() {
2895                        Some(DiffTransform::BufferContent {
2896                            inserted_hunk_info: Some(hunk),
2897                            ..
2898                        }) => excerpts.item().is_some_and(|excerpt| {
2899                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2900                        }),
2901                        _ => true,
2902                    };
2903
2904                let mut excerpt_offset = edit.new.end;
2905                if !keep_next_old_transform {
2906                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
2907                    old_diff_transforms.next(&());
2908                }
2909
2910                old_expanded_hunks.clear();
2911                self.push_buffer_content_transform(
2912                    &snapshot,
2913                    &mut new_diff_transforms,
2914                    excerpt_offset,
2915                    end_of_current_insert,
2916                );
2917                at_transform_boundary = true;
2918            }
2919        }
2920
2921        // Keep any transforms that are after the last edit.
2922        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
2923
2924        // Ensure there's always at least one buffer content transform.
2925        if new_diff_transforms.is_empty() {
2926            new_diff_transforms.push(
2927                DiffTransform::BufferContent {
2928                    summary: Default::default(),
2929                    inserted_hunk_info: None,
2930                },
2931                &(),
2932            );
2933        }
2934
2935        self.subscriptions.publish(output_edits);
2936        drop(old_diff_transforms);
2937        drop(excerpts);
2938        snapshot.diff_transforms = new_diff_transforms;
2939        snapshot.edit_count += 1;
2940
2941        #[cfg(any(test, feature = "test-support"))]
2942        snapshot.check_invariants();
2943    }
2944
2945    #[allow(clippy::too_many_arguments)]
2946    fn recompute_diff_transforms_for_edit(
2947        &self,
2948        edit: &Edit<TypedOffset<Excerpt>>,
2949        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2950        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
2951        new_diff_transforms: &mut SumTree<DiffTransform>,
2952        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2953        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2954        snapshot: &MultiBufferSnapshot,
2955        change_kind: DiffChangeKind,
2956    ) -> bool {
2957        log::trace!(
2958            "recomputing diff transform for edit {:?} => {:?}",
2959            edit.old.start.value..edit.old.end.value,
2960            edit.new.start.value..edit.new.end.value
2961        );
2962
2963        // Record which hunks were previously expanded.
2964        while let Some(item) = old_diff_transforms.item() {
2965            if let Some(hunk_info) = item.hunk_info() {
2966                log::trace!(
2967                    "previously expanded hunk at {}",
2968                    old_diff_transforms.start().0
2969                );
2970                old_expanded_hunks.insert(hunk_info);
2971            }
2972            if old_diff_transforms.end(&()).0 > edit.old.end {
2973                break;
2974            }
2975            old_diff_transforms.next(&());
2976        }
2977
2978        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2979        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2980        if old_expanded_hunks.is_empty()
2981            && change_kind == DiffChangeKind::BufferEdited
2982            && !all_diff_hunks_expanded
2983        {
2984            return false;
2985        }
2986
2987        // Visit each excerpt that intersects the edit.
2988        let mut did_expand_hunks = false;
2989        while let Some(excerpt) = excerpts.item() {
2990            // Recompute the expanded hunks in the portion of the excerpt that
2991            // intersects the edit.
2992            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2993                let buffer = &excerpt.buffer;
2994                let excerpt_start = *excerpts.start();
2995                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2996                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2997                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2998                let edit_buffer_start =
2999                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3000                let edit_buffer_end =
3001                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3002                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3003                let edit_anchor_range =
3004                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3005
3006                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3007                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3008                        continue;
3009                    }
3010
3011                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3012                    if hunk_buffer_range.start < excerpt_buffer_start {
3013                        log::trace!("skipping hunk that starts before excerpt");
3014                        continue;
3015                    }
3016
3017                    let hunk_info = DiffTransformHunkInfo {
3018                        excerpt_id: excerpt.id,
3019                        hunk_start_anchor: hunk.buffer_range.start,
3020                        hunk_secondary_status: hunk.secondary_status,
3021                    };
3022
3023                    let hunk_excerpt_start = excerpt_start
3024                        + ExcerptOffset::new(
3025                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3026                        );
3027                    let hunk_excerpt_end = excerpt_end.min(
3028                        excerpt_start
3029                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3030                    );
3031
3032                    self.push_buffer_content_transform(
3033                        snapshot,
3034                        new_diff_transforms,
3035                        hunk_excerpt_start,
3036                        *end_of_current_insert,
3037                    );
3038
3039                    // For every existing hunk, determine if it was previously expanded
3040                    // and if it should currently be expanded.
3041                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3042                    let should_expand_hunk = match &change_kind {
3043                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3044                            was_previously_expanded || all_diff_hunks_expanded
3045                        }
3046                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3047                            let intersects = hunk_buffer_range.is_empty()
3048                                || hunk_buffer_range.end > edit_buffer_start;
3049                            if *expand {
3050                                intersects || was_previously_expanded || all_diff_hunks_expanded
3051                            } else {
3052                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3053                            }
3054                        }
3055                        _ => was_previously_expanded || all_diff_hunks_expanded,
3056                    };
3057
3058                    if should_expand_hunk {
3059                        did_expand_hunks = true;
3060                        log::trace!(
3061                            "expanding hunk {:?}, excerpt:{:?}",
3062                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3063                            excerpt.id
3064                        );
3065
3066                        if !hunk.diff_base_byte_range.is_empty()
3067                            && hunk_buffer_range.start >= edit_buffer_start
3068                            && hunk_buffer_range.start <= excerpt_buffer_end
3069                        {
3070                            let base_text = diff.base_text();
3071                            let mut text_cursor =
3072                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3073                            let mut base_text_summary =
3074                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3075
3076                            let mut has_trailing_newline = false;
3077                            if base_text_summary.last_line_chars > 0 {
3078                                base_text_summary += TextSummary::newline();
3079                                has_trailing_newline = true;
3080                            }
3081
3082                            new_diff_transforms.push(
3083                                DiffTransform::DeletedHunk {
3084                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3085                                    summary: base_text_summary,
3086                                    buffer_id: excerpt.buffer_id,
3087                                    hunk_info,
3088                                    has_trailing_newline,
3089                                },
3090                                &(),
3091                            );
3092                        }
3093
3094                        if !hunk_buffer_range.is_empty() {
3095                            *end_of_current_insert =
3096                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3097                        }
3098                    }
3099                }
3100            }
3101
3102            if excerpts.end(&()) <= edit.new.end {
3103                excerpts.next(&());
3104            } else {
3105                break;
3106            }
3107        }
3108
3109        did_expand_hunks || !old_expanded_hunks.is_empty()
3110    }
3111
3112    fn append_diff_transforms(
3113        &self,
3114        new_transforms: &mut SumTree<DiffTransform>,
3115        subtree: SumTree<DiffTransform>,
3116    ) {
3117        if let Some(DiffTransform::BufferContent {
3118            inserted_hunk_info,
3119            summary,
3120        }) = subtree.first()
3121        {
3122            if self.extend_last_buffer_content_transform(
3123                new_transforms,
3124                *inserted_hunk_info,
3125                *summary,
3126            ) {
3127                let mut cursor = subtree.cursor::<()>(&());
3128                cursor.next(&());
3129                cursor.next(&());
3130                new_transforms.append(cursor.suffix(&()), &());
3131                return;
3132            }
3133        }
3134        new_transforms.append(subtree, &());
3135    }
3136
3137    fn push_diff_transform(
3138        &self,
3139        new_transforms: &mut SumTree<DiffTransform>,
3140        transform: DiffTransform,
3141    ) {
3142        if let DiffTransform::BufferContent {
3143            inserted_hunk_info: inserted_hunk_anchor,
3144            summary,
3145        } = transform
3146        {
3147            if self.extend_last_buffer_content_transform(
3148                new_transforms,
3149                inserted_hunk_anchor,
3150                summary,
3151            ) {
3152                return;
3153            }
3154        }
3155        new_transforms.push(transform, &());
3156    }
3157
3158    fn push_buffer_content_transform(
3159        &self,
3160        old_snapshot: &MultiBufferSnapshot,
3161        new_transforms: &mut SumTree<DiffTransform>,
3162        end_offset: ExcerptOffset,
3163        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3164    ) {
3165        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3166            (end_offset.min(insertion_end_offset), Some(hunk_info))
3167        });
3168        let unchanged_region = [(end_offset, None)];
3169
3170        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3171        {
3172            let start_offset = new_transforms.summary().excerpt_len();
3173            if end_offset <= start_offset {
3174                continue;
3175            }
3176            let summary_to_add = old_snapshot
3177                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3178
3179            if !self.extend_last_buffer_content_transform(
3180                new_transforms,
3181                inserted_hunk_info,
3182                summary_to_add,
3183            ) {
3184                new_transforms.push(
3185                    DiffTransform::BufferContent {
3186                        summary: summary_to_add,
3187                        inserted_hunk_info,
3188                    },
3189                    &(),
3190                )
3191            }
3192        }
3193    }
3194
3195    fn extend_last_buffer_content_transform(
3196        &self,
3197        new_transforms: &mut SumTree<DiffTransform>,
3198        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3199        summary_to_add: TextSummary,
3200    ) -> bool {
3201        let mut did_extend = false;
3202        new_transforms.update_last(
3203            |last_transform| {
3204                if let DiffTransform::BufferContent {
3205                    summary,
3206                    inserted_hunk_info: inserted_hunk_anchor,
3207                } = last_transform
3208                {
3209                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3210                        *summary += summary_to_add;
3211                        did_extend = true;
3212                    }
3213                }
3214            },
3215            &(),
3216        );
3217        did_extend
3218    }
3219}
3220
3221#[cfg(any(test, feature = "test-support"))]
3222impl MultiBuffer {
3223    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3224        let buffer = cx.new(|cx| Buffer::local(text, cx));
3225        cx.new(|cx| Self::singleton(buffer, cx))
3226    }
3227
3228    pub fn build_multi<const COUNT: usize>(
3229        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3230        cx: &mut gpui::App,
3231    ) -> Entity<Self> {
3232        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3233        for (text, ranges) in excerpts {
3234            let buffer = cx.new(|cx| Buffer::local(text, cx));
3235            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
3236                context: range,
3237                primary: None,
3238            });
3239            multi.update(cx, |multi, cx| {
3240                multi.push_excerpts(buffer, excerpt_ranges, cx)
3241            });
3242        }
3243
3244        multi
3245    }
3246
3247    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3248        cx.new(|cx| Self::singleton(buffer, cx))
3249    }
3250
3251    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3252        cx.new(|cx| {
3253            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3254            let mutation_count = rng.gen_range(1..=5);
3255            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3256            multibuffer
3257        })
3258    }
3259
3260    pub fn randomly_edit(
3261        &mut self,
3262        rng: &mut impl rand::Rng,
3263        edit_count: usize,
3264        cx: &mut Context<Self>,
3265    ) {
3266        use util::RandomCharIter;
3267
3268        let snapshot = self.read(cx);
3269        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3270        let mut last_end = None;
3271        for _ in 0..edit_count {
3272            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3273                break;
3274            }
3275
3276            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3277            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3278            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3279            last_end = Some(end);
3280
3281            let mut range = start..end;
3282            if rng.gen_bool(0.2) {
3283                mem::swap(&mut range.start, &mut range.end);
3284            }
3285
3286            let new_text_len = rng.gen_range(0..10);
3287            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3288
3289            edits.push((range, new_text.into()));
3290        }
3291        log::info!("mutating multi-buffer with {:?}", edits);
3292        drop(snapshot);
3293
3294        self.edit(edits, None, cx);
3295    }
3296
3297    pub fn randomly_edit_excerpts(
3298        &mut self,
3299        rng: &mut impl rand::Rng,
3300        mutation_count: usize,
3301        cx: &mut Context<Self>,
3302    ) {
3303        use rand::prelude::*;
3304        use std::env;
3305        use util::RandomCharIter;
3306
3307        let max_excerpts = env::var("MAX_EXCERPTS")
3308            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3309            .unwrap_or(5);
3310
3311        let mut buffers = Vec::new();
3312        for _ in 0..mutation_count {
3313            if rng.gen_bool(0.05) {
3314                log::info!("Clearing multi-buffer");
3315                self.clear(cx);
3316                continue;
3317            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3318                let ids = self.excerpt_ids();
3319                let mut excerpts = HashSet::default();
3320                for _ in 0..rng.gen_range(0..ids.len()) {
3321                    excerpts.extend(ids.choose(rng).copied());
3322                }
3323
3324                let line_count = rng.gen_range(0..5);
3325
3326                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3327
3328                self.expand_excerpts(
3329                    excerpts.iter().cloned(),
3330                    line_count,
3331                    ExpandExcerptDirection::UpAndDown,
3332                    cx,
3333                );
3334                continue;
3335            }
3336
3337            let excerpt_ids = self.excerpt_ids();
3338            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
3339                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
3340                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3341                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3342                    let buffer = buffers.last().unwrap().read(cx);
3343                    log::info!(
3344                        "Creating new buffer {} with text: {:?}",
3345                        buffer.remote_id(),
3346                        buffer.text()
3347                    );
3348                    buffers.last().unwrap().clone()
3349                } else {
3350                    self.buffers
3351                        .borrow()
3352                        .values()
3353                        .choose(rng)
3354                        .unwrap()
3355                        .buffer
3356                        .clone()
3357                };
3358
3359                let buffer = buffer_handle.read(cx);
3360                let buffer_text = buffer.text();
3361                let ranges = (0..rng.gen_range(0..5))
3362                    .map(|_| {
3363                        let end_ix =
3364                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3365                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3366                        ExcerptRange {
3367                            context: start_ix..end_ix,
3368                            primary: None,
3369                        }
3370                    })
3371                    .collect::<Vec<_>>();
3372                log::info!(
3373                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3374                    buffer_handle.read(cx).remote_id(),
3375                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3376                    ranges
3377                        .iter()
3378                        .map(|r| &buffer_text[r.context.clone()])
3379                        .collect::<Vec<_>>()
3380                );
3381
3382                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3383                log::info!("Inserted with ids: {:?}", excerpt_id);
3384            } else {
3385                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3386                let mut excerpts_to_remove = excerpt_ids
3387                    .choose_multiple(rng, remove_count)
3388                    .cloned()
3389                    .collect::<Vec<_>>();
3390                let snapshot = self.snapshot.borrow();
3391                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3392                drop(snapshot);
3393                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3394                self.remove_excerpts(excerpts_to_remove, cx);
3395            }
3396        }
3397    }
3398
3399    pub fn randomly_mutate(
3400        &mut self,
3401        rng: &mut impl rand::Rng,
3402        mutation_count: usize,
3403        cx: &mut Context<Self>,
3404    ) {
3405        use rand::prelude::*;
3406
3407        if rng.gen_bool(0.7) || self.singleton {
3408            let buffer = self
3409                .buffers
3410                .borrow()
3411                .values()
3412                .choose(rng)
3413                .map(|state| state.buffer.clone());
3414
3415            if let Some(buffer) = buffer {
3416                buffer.update(cx, |buffer, cx| {
3417                    if rng.gen() {
3418                        buffer.randomly_edit(rng, mutation_count, cx);
3419                    } else {
3420                        buffer.randomly_undo_redo(rng, cx);
3421                    }
3422                });
3423            } else {
3424                self.randomly_edit(rng, mutation_count, cx);
3425            }
3426        } else {
3427            self.randomly_edit_excerpts(rng, mutation_count, cx);
3428        }
3429
3430        self.check_invariants(cx);
3431    }
3432
3433    fn check_invariants(&self, cx: &App) {
3434        self.read(cx).check_invariants();
3435    }
3436}
3437
3438impl EventEmitter<Event> for MultiBuffer {}
3439
3440impl MultiBufferSnapshot {
3441    pub fn text(&self) -> String {
3442        self.chunks(0..self.len(), false)
3443            .map(|chunk| chunk.text)
3444            .collect()
3445    }
3446
3447    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3448        self.reversed_chunks_in_range(0..position.to_offset(self))
3449            .flat_map(|c| c.chars().rev())
3450    }
3451
3452    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3453        let mut cursor = self.cursor::<usize>();
3454        cursor.seek(&range.end);
3455        let current_chunks = cursor.region().as_ref().map(|region| {
3456            let start_overshoot = range.start.saturating_sub(region.range.start);
3457            let end_overshoot = range.end - region.range.start;
3458            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3459            let start = region.buffer_range.start + start_overshoot;
3460            region.buffer.reversed_chunks_in_range(start..end)
3461        });
3462        ReversedMultiBufferChunks {
3463            cursor,
3464            current_chunks,
3465            start: range.start,
3466            offset: range.end,
3467        }
3468    }
3469
3470    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3471        let offset = position.to_offset(self);
3472        self.text_for_range(offset..self.len())
3473            .flat_map(|chunk| chunk.chars())
3474    }
3475
3476    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3477        self.chunks(range, false).map(|chunk| chunk.text)
3478    }
3479
3480    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3481        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3482            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3483    }
3484
3485    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3486    where
3487        T: ToOffset,
3488    {
3489        let position = position.to_offset(self);
3490        position == self.clip_offset(position, Bias::Left)
3491            && self
3492                .bytes_in_range(position..self.len())
3493                .flatten()
3494                .copied()
3495                .take(needle.len())
3496                .eq(needle.bytes())
3497    }
3498
3499    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3500        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3501    }
3502
3503    pub fn diff_hunks_in_range<T: ToPoint>(
3504        &self,
3505        range: Range<T>,
3506    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3507        let query_range = range.start.to_point(self)..range.end.to_point(self);
3508        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3509            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
3510                log::debug!("no diff found for {:?}", buffer.remote_id());
3511                return None;
3512            };
3513            let buffer_start = buffer.anchor_before(buffer_range.start);
3514            let buffer_end = buffer.anchor_after(buffer_range.end);
3515            Some(
3516                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3517                    .filter_map(|hunk| {
3518                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3519                            return None;
3520                        }
3521                        Some((hunk.range.clone(), hunk))
3522                    }),
3523            )
3524        })
3525        .filter_map(move |(range, hunk, excerpt)| {
3526            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3527            {
3528                return None;
3529            }
3530            let end_row = if range.end.column == 0 {
3531                range.end.row
3532            } else {
3533                range.end.row + 1
3534            };
3535            Some(MultiBufferDiffHunk {
3536                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3537                buffer_id: excerpt.buffer_id,
3538                excerpt_id: excerpt.id,
3539                buffer_range: hunk.buffer_range.clone(),
3540                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3541                secondary_status: hunk.secondary_status,
3542            })
3543        })
3544    }
3545
3546    pub fn excerpt_ids_for_range<T: ToOffset>(
3547        &self,
3548        range: Range<T>,
3549    ) -> impl Iterator<Item = ExcerptId> + '_ {
3550        let range = range.start.to_offset(self)..range.end.to_offset(self);
3551        let mut cursor = self.cursor::<usize>();
3552        cursor.seek(&range.start);
3553        std::iter::from_fn(move || {
3554            let region = cursor.region()?;
3555            if region.range.start >= range.end {
3556                return None;
3557            }
3558            cursor.next_excerpt();
3559            Some(region.excerpt.id)
3560        })
3561    }
3562
3563    pub fn buffer_ids_for_range<T: ToOffset>(
3564        &self,
3565        range: Range<T>,
3566    ) -> impl Iterator<Item = BufferId> + '_ {
3567        let range = range.start.to_offset(self)..range.end.to_offset(self);
3568        let mut cursor = self.cursor::<usize>();
3569        cursor.seek(&range.start);
3570        std::iter::from_fn(move || {
3571            let region = cursor.region()?;
3572            if region.range.start > range.end
3573                || region.range.start == range.end && region.range.start > range.start
3574            {
3575                return None;
3576            }
3577            cursor.next_excerpt();
3578            Some(region.excerpt.buffer_id)
3579        })
3580    }
3581
3582    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3583        &self,
3584        ranges: impl Iterator<Item = Range<T>>,
3585    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3586        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3587    }
3588
3589    pub fn range_to_buffer_ranges<T: ToOffset>(
3590        &self,
3591        range: Range<T>,
3592    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3593        let start = range.start.to_offset(&self);
3594        let end = range.end.to_offset(&self);
3595
3596        let mut cursor = self.cursor::<usize>();
3597        cursor.seek(&start);
3598
3599        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3600        while let Some(region) = cursor.region() {
3601            if region.range.start > end {
3602                break;
3603            }
3604            if region.is_main_buffer {
3605                let start_overshoot = start.saturating_sub(region.range.start);
3606                let end_overshoot = end.saturating_sub(region.range.start);
3607                let start = region
3608                    .buffer_range
3609                    .end
3610                    .min(region.buffer_range.start + start_overshoot);
3611                let end = region
3612                    .buffer_range
3613                    .end
3614                    .min(region.buffer_range.start + end_overshoot);
3615                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3616                    *excerpt_id == region.excerpt.id && prev_range.end == start
3617                }) {
3618                    prev.1.end = end;
3619                } else {
3620                    result.push((region.buffer, start..end, region.excerpt.id));
3621                }
3622            }
3623            cursor.next();
3624        }
3625        result
3626    }
3627
3628    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3629        &self,
3630        range: Range<T>,
3631    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3632        let start = range.start.to_offset(&self);
3633        let end = range.end.to_offset(&self);
3634
3635        let mut cursor = self.cursor::<usize>();
3636        cursor.seek(&start);
3637
3638        std::iter::from_fn(move || {
3639            let region = cursor.region()?;
3640            if region.range.start > end {
3641                return None;
3642            }
3643            let start_overshoot = start.saturating_sub(region.range.start);
3644            let end_overshoot = end.saturating_sub(region.range.start);
3645            let start = region
3646                .buffer_range
3647                .end
3648                .min(region.buffer_range.start + start_overshoot);
3649            let end = region
3650                .buffer_range
3651                .end
3652                .min(region.buffer_range.start + end_overshoot);
3653
3654            let region_excerpt_id = region.excerpt.id;
3655            let deleted_hunk_anchor = if region.is_main_buffer {
3656                None
3657            } else {
3658                Some(self.anchor_before(region.range.start))
3659            };
3660            let result = (
3661                region.buffer,
3662                start..end,
3663                region_excerpt_id,
3664                deleted_hunk_anchor,
3665            );
3666            cursor.next();
3667            Some(result)
3668        })
3669    }
3670
3671    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3672    /// coordinates.
3673    ///
3674    /// The given callback will be called for every excerpt intersecting the given range. It will
3675    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3676    /// The callback should return an iterator of metadata items from that buffer, each paired
3677    /// with a buffer range.
3678    ///
3679    /// The returned iterator yields each of these metadata items, paired with its range in
3680    /// multi-buffer coordinates.
3681    fn lift_buffer_metadata<'a, D, M, I>(
3682        &'a self,
3683        query_range: Range<D>,
3684        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3685    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3686    where
3687        I: Iterator<Item = (Range<D>, M)> + 'a,
3688        D: TextDimension + Ord + Sub<D, Output = D>,
3689    {
3690        let max_position = D::from_text_summary(&self.text_summary());
3691        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3692        let mut cursor = self.cursor::<D>();
3693
3694        // Find the excerpt and buffer offset where the given range ends.
3695        cursor.seek(&query_range.end);
3696        let mut range_end = None;
3697        while let Some(region) = cursor.region() {
3698            if region.is_main_buffer {
3699                let mut buffer_end = region.buffer_range.start;
3700                let overshoot = if query_range.end > region.range.start {
3701                    query_range.end - region.range.start
3702                } else {
3703                    D::default()
3704                };
3705                buffer_end.add_assign(&overshoot);
3706                range_end = Some((region.excerpt.id, buffer_end));
3707                break;
3708            }
3709            cursor.next();
3710        }
3711
3712        cursor.seek(&query_range.start);
3713
3714        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3715            if region.range.start > D::zero(&()) {
3716                cursor.prev()
3717            }
3718        }
3719
3720        iter::from_fn(move || loop {
3721            let excerpt = cursor.excerpt()?;
3722
3723            // If we have already retrieved metadata for this excerpt, continue to use it.
3724            let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3725                .as_mut()
3726                .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3727            {
3728                Some(metadata)
3729            }
3730            // Otherwise, compute the intersection of the input range with the excerpt's range,
3731            // and retrieve the metadata for the resulting range.
3732            else {
3733                let region = cursor.region()?;
3734                let mut buffer_start;
3735                if region.is_main_buffer {
3736                    buffer_start = region.buffer_range.start;
3737                    if query_range.start > region.range.start {
3738                        let overshoot = query_range.start - region.range.start;
3739                        buffer_start.add_assign(&overshoot);
3740                    }
3741                    buffer_start = buffer_start.min(region.buffer_range.end);
3742                } else {
3743                    buffer_start = cursor.main_buffer_position()?;
3744                };
3745                let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3746                if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3747                    if excerpt.id == end_excerpt_id {
3748                        buffer_end = buffer_end.min(end_buffer_offset);
3749                    }
3750                }
3751
3752                if let Some(iterator) =
3753                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3754                {
3755                    Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3756                } else {
3757                    None
3758                }
3759            };
3760
3761            // Visit each metadata item.
3762            if let Some((metadata_buffer_range, metadata)) = metadata_iter.and_then(Iterator::next)
3763            {
3764                // Find the multibuffer regions that contain the start and end of
3765                // the metadata item's range.
3766                if metadata_buffer_range.start > D::default() {
3767                    while let Some(region) = cursor.region() {
3768                        if region.is_main_buffer
3769                            && (region.buffer_range.end >= metadata_buffer_range.start
3770                                || cursor.is_at_end_of_excerpt())
3771                        {
3772                            break;
3773                        }
3774                        cursor.next();
3775                    }
3776                }
3777                let start_region = cursor.region()?;
3778                while let Some(region) = cursor.region() {
3779                    if region.is_main_buffer
3780                        && (region.buffer_range.end > metadata_buffer_range.end
3781                            || cursor.is_at_end_of_excerpt())
3782                    {
3783                        break;
3784                    }
3785                    cursor.next();
3786                }
3787                let end_region = cursor.region();
3788
3789                // Convert the metadata item's range into multibuffer coordinates.
3790                let mut start_position = start_region.range.start;
3791                let region_buffer_start = start_region.buffer_range.start;
3792                if start_region.is_main_buffer && metadata_buffer_range.start > region_buffer_start
3793                {
3794                    start_position.add_assign(&(metadata_buffer_range.start - region_buffer_start));
3795                    start_position = start_position.min(start_region.range.end);
3796                }
3797
3798                let mut end_position = max_position;
3799                if let Some(end_region) = &end_region {
3800                    end_position = end_region.range.start;
3801                    debug_assert!(end_region.is_main_buffer);
3802                    let region_buffer_start = end_region.buffer_range.start;
3803                    if metadata_buffer_range.end > region_buffer_start {
3804                        end_position.add_assign(&(metadata_buffer_range.end - region_buffer_start));
3805                    }
3806                    end_position = end_position.min(end_region.range.end);
3807                }
3808
3809                if start_position <= query_range.end && end_position >= query_range.start {
3810                    return Some((start_position..end_position, metadata, excerpt));
3811                }
3812            }
3813            // When there are no more metadata items for this excerpt, move to the next excerpt.
3814            else {
3815                current_excerpt_metadata.take();
3816                cursor.next_excerpt();
3817            }
3818        })
3819    }
3820
3821    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferDiffHunk> {
3822        let offset = position.to_offset(self);
3823
3824        // Go to the region containing the given offset.
3825        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3826        cursor.seek(&DimensionPair {
3827            key: offset,
3828            value: None,
3829        });
3830        let mut region = cursor.region()?;
3831        if region.range.start.key == offset || !region.is_main_buffer {
3832            cursor.prev();
3833            region = cursor.region()?;
3834        }
3835
3836        // Find the corresponding buffer offset.
3837        let overshoot = if region.is_main_buffer {
3838            offset - region.range.start.key
3839        } else {
3840            0
3841        };
3842        let mut max_buffer_offset = region
3843            .buffer
3844            .clip_offset(region.buffer_range.start.key + overshoot, Bias::Right);
3845
3846        loop {
3847            let excerpt = cursor.excerpt()?;
3848            let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3849            let buffer_offset = excerpt_end.min(max_buffer_offset);
3850            let buffer_end = excerpt.buffer.anchor_before(buffer_offset);
3851            let buffer_end_row = buffer_end.to_point(&excerpt.buffer).row;
3852
3853            if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3854                for hunk in diff.hunks_intersecting_range_rev(
3855                    excerpt.range.context.start..buffer_end,
3856                    &excerpt.buffer,
3857                ) {
3858                    let hunk_range = hunk.buffer_range.to_offset(&excerpt.buffer);
3859                    if hunk.range.end >= Point::new(buffer_end_row, 0) {
3860                        continue;
3861                    }
3862
3863                    let hunk_start = hunk.range.start;
3864                    let hunk_end = hunk.range.end;
3865
3866                    cursor.seek_to_buffer_position_in_current_excerpt(&DimensionPair {
3867                        key: hunk_range.start,
3868                        value: None,
3869                    });
3870
3871                    let mut region = cursor.region()?;
3872                    while !region.is_main_buffer || region.buffer_range.start.key >= hunk_range.end
3873                    {
3874                        cursor.prev();
3875                        region = cursor.region()?;
3876                    }
3877
3878                    let overshoot = if region.is_main_buffer {
3879                        hunk_start.saturating_sub(region.buffer_range.start.value.unwrap())
3880                    } else {
3881                        Point::zero()
3882                    };
3883                    let start = region.range.start.value.unwrap() + overshoot;
3884
3885                    while let Some(region) = cursor.region() {
3886                        if !region.is_main_buffer
3887                            || region.buffer_range.end.value.unwrap() <= hunk_end
3888                        {
3889                            cursor.next();
3890                        } else {
3891                            break;
3892                        }
3893                    }
3894
3895                    let end = if let Some(region) = cursor.region() {
3896                        let overshoot = if region.is_main_buffer {
3897                            hunk_end.saturating_sub(region.buffer_range.start.value.unwrap())
3898                        } else {
3899                            Point::zero()
3900                        };
3901                        region.range.start.value.unwrap() + overshoot
3902                    } else {
3903                        self.max_point()
3904                    };
3905
3906                    return Some(MultiBufferDiffHunk {
3907                        row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
3908                        buffer_id: excerpt.buffer_id,
3909                        excerpt_id: excerpt.id,
3910                        buffer_range: hunk.buffer_range.clone(),
3911                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3912                        secondary_status: hunk.secondary_status,
3913                    });
3914                }
3915            }
3916
3917            cursor.prev_excerpt();
3918            max_buffer_offset = usize::MAX;
3919        }
3920    }
3921
3922    pub fn has_diff_hunks(&self) -> bool {
3923        self.diffs.values().any(|diff| !diff.is_empty())
3924    }
3925
3926    pub fn surrounding_word<T: ToOffset>(
3927        &self,
3928        start: T,
3929        for_completion: bool,
3930    ) -> (Range<usize>, Option<CharKind>) {
3931        let mut start = start.to_offset(self);
3932        let mut end = start;
3933        let mut next_chars = self.chars_at(start).peekable();
3934        let mut prev_chars = self.reversed_chars_at(start).peekable();
3935
3936        let classifier = self
3937            .char_classifier_at(start)
3938            .for_completion(for_completion);
3939
3940        let word_kind = cmp::max(
3941            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3942            next_chars.peek().copied().map(|c| classifier.kind(c)),
3943        );
3944
3945        for ch in prev_chars {
3946            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3947                start -= ch.len_utf8();
3948            } else {
3949                break;
3950            }
3951        }
3952
3953        for ch in next_chars {
3954            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3955                end += ch.len_utf8();
3956            } else {
3957                break;
3958            }
3959        }
3960
3961        (start..end, word_kind)
3962    }
3963
3964    pub fn is_singleton(&self) -> bool {
3965        self.singleton
3966    }
3967
3968    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3969        if self.singleton {
3970            self.excerpts
3971                .iter()
3972                .next()
3973                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3974        } else {
3975            None
3976        }
3977    }
3978
3979    pub fn len(&self) -> usize {
3980        self.diff_transforms.summary().output.len
3981    }
3982
3983    pub fn is_empty(&self) -> bool {
3984        self.excerpts.summary().text.len == 0
3985    }
3986
3987    pub fn widest_line_number(&self) -> u32 {
3988        self.excerpts.summary().widest_line_number + 1
3989    }
3990
3991    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
3992        let range = range.start.to_offset(self)..range.end.to_offset(self);
3993        let mut excerpts = self.cursor::<usize>();
3994        excerpts.seek(&range.start);
3995
3996        let mut chunk;
3997        let mut has_trailing_newline;
3998        let excerpt_bytes;
3999        if let Some(region) = excerpts.region() {
4000            let mut bytes = region.buffer.bytes_in_range(
4001                region.buffer_range.start + range.start - region.range.start
4002                    ..(region.buffer_range.start + range.end - region.range.start)
4003                        .min(region.buffer_range.end),
4004            );
4005            chunk = bytes.next().unwrap_or(&[][..]);
4006            excerpt_bytes = Some(bytes);
4007            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4008            if chunk.is_empty() && has_trailing_newline {
4009                chunk = b"\n";
4010                has_trailing_newline = false;
4011            }
4012        } else {
4013            chunk = &[][..];
4014            excerpt_bytes = None;
4015            has_trailing_newline = false;
4016        };
4017
4018        MultiBufferBytes {
4019            range,
4020            cursor: excerpts,
4021            excerpt_bytes,
4022            has_trailing_newline,
4023            chunk,
4024        }
4025    }
4026
4027    pub fn reversed_bytes_in_range<T: ToOffset>(
4028        &self,
4029        range: Range<T>,
4030    ) -> ReversedMultiBufferBytes {
4031        let range = range.start.to_offset(self)..range.end.to_offset(self);
4032        let mut chunks = self.reversed_chunks_in_range(range.clone());
4033        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4034        ReversedMultiBufferBytes {
4035            range,
4036            chunks,
4037            chunk,
4038        }
4039    }
4040
4041    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4042        let mut cursor = self.cursor::<Point>();
4043        cursor.seek(&Point::new(start_row.0, 0));
4044        let mut result = MultiBufferRows {
4045            point: Point::new(0, 0),
4046            is_empty: self.excerpts.is_empty(),
4047            cursor,
4048        };
4049        result.seek(start_row);
4050        result
4051    }
4052
4053    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4054        let mut chunks = MultiBufferChunks {
4055            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4056            range: 0..0,
4057            excerpts: self.excerpts.cursor(&()),
4058            diff_transforms: self.diff_transforms.cursor(&()),
4059            diffs: &self.diffs,
4060            diff_base_chunks: None,
4061            excerpt_chunks: None,
4062            buffer_chunk: None,
4063            language_aware,
4064        };
4065        let range = range.start.to_offset(self)..range.end.to_offset(self);
4066        chunks.seek(range);
4067        chunks
4068    }
4069
4070    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4071        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4072    }
4073
4074    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4075        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4076    }
4077
4078    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4079        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4080    }
4081
4082    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4083        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4084            buffer.clip_point_utf16(Unclipped(point), bias)
4085        })
4086    }
4087
4088    pub fn offset_to_point(&self, offset: usize) -> Point {
4089        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4090    }
4091
4092    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4093        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4094    }
4095
4096    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4097        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4098    }
4099
4100    pub fn point_to_offset(&self, point: Point) -> usize {
4101        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4102    }
4103
4104    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4105        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4106    }
4107
4108    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4109        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4110    }
4111
4112    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4113        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4114    }
4115
4116    fn clip_dimension<D>(
4117        &self,
4118        position: D,
4119        bias: Bias,
4120        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4121    ) -> D
4122    where
4123        D: TextDimension + Ord + Sub<D, Output = D>,
4124    {
4125        let mut cursor = self.cursor();
4126        cursor.seek(&position);
4127        if let Some(region) = cursor.region() {
4128            if position >= region.range.end {
4129                return region.range.end;
4130            }
4131            let overshoot = position - region.range.start;
4132            let mut buffer_position = region.buffer_range.start;
4133            buffer_position.add_assign(&overshoot);
4134            let clipped_buffer_position =
4135                clip_buffer_position(&region.buffer, buffer_position, bias);
4136            let mut position = region.range.start;
4137            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4138            position
4139        } else {
4140            D::from_text_summary(&self.text_summary())
4141        }
4142    }
4143
4144    fn convert_dimension<D1, D2>(
4145        &self,
4146        key: D1,
4147        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4148    ) -> D2
4149    where
4150        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4151        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4152    {
4153        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4154        cursor.seek(&DimensionPair { key, value: None });
4155        if let Some(region) = cursor.region() {
4156            if key >= region.range.end.key {
4157                return region.range.end.value.unwrap();
4158            }
4159            let start_key = region.range.start.key;
4160            let start_value = region.range.start.value.unwrap();
4161            let buffer_start_key = region.buffer_range.start.key;
4162            let buffer_start_value = region.buffer_range.start.value.unwrap();
4163            let mut buffer_key = buffer_start_key;
4164            buffer_key.add_assign(&(key - start_key));
4165            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4166            let mut result = start_value;
4167            result.add_assign(&(buffer_value - buffer_start_value));
4168            result
4169        } else {
4170            D2::from_text_summary(&self.text_summary())
4171        }
4172    }
4173
4174    pub fn point_to_buffer_offset<T: ToOffset>(
4175        &self,
4176        point: T,
4177    ) -> Option<(&BufferSnapshot, usize)> {
4178        let offset = point.to_offset(self);
4179        let mut cursor = self.cursor::<usize>();
4180        cursor.seek(&offset);
4181        let region = cursor.region()?;
4182        let overshoot = offset - region.range.start;
4183        let buffer_offset = region.buffer_range.start + overshoot;
4184        Some((region.buffer, buffer_offset))
4185    }
4186
4187    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point, bool)> {
4188        let mut cursor = self.cursor::<Point>();
4189        cursor.seek(&point);
4190        let region = cursor.region()?;
4191        let overshoot = point - region.range.start;
4192        let buffer_offset = region.buffer_range.start + overshoot;
4193        Some((region.buffer, buffer_offset, region.is_main_buffer))
4194    }
4195
4196    pub fn suggested_indents(
4197        &self,
4198        rows: impl IntoIterator<Item = u32>,
4199        cx: &App,
4200    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4201        let mut result = BTreeMap::new();
4202
4203        let mut rows_for_excerpt = Vec::new();
4204        let mut cursor = self.cursor::<Point>();
4205        let mut rows = rows.into_iter().peekable();
4206        let mut prev_row = u32::MAX;
4207        let mut prev_language_indent_size = IndentSize::default();
4208
4209        while let Some(row) = rows.next() {
4210            cursor.seek(&Point::new(row, 0));
4211            let Some(region) = cursor.region() else {
4212                continue;
4213            };
4214
4215            // Retrieve the language and indent size once for each disjoint region being indented.
4216            let single_indent_size = if row.saturating_sub(1) == prev_row {
4217                prev_language_indent_size
4218            } else {
4219                region
4220                    .buffer
4221                    .language_indent_size_at(Point::new(row, 0), cx)
4222            };
4223            prev_language_indent_size = single_indent_size;
4224            prev_row = row;
4225
4226            let start_buffer_row = region.buffer_range.start.row;
4227            let start_multibuffer_row = region.range.start.row;
4228            let end_multibuffer_row = region.range.end.row;
4229
4230            rows_for_excerpt.push(row);
4231            while let Some(next_row) = rows.peek().copied() {
4232                if end_multibuffer_row > next_row {
4233                    rows_for_excerpt.push(next_row);
4234                    rows.next();
4235                } else {
4236                    break;
4237                }
4238            }
4239
4240            let buffer_rows = rows_for_excerpt
4241                .drain(..)
4242                .map(|row| start_buffer_row + row - start_multibuffer_row);
4243            let buffer_indents = region
4244                .buffer
4245                .suggested_indents(buffer_rows, single_indent_size);
4246            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4247                (
4248                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4249                    indent,
4250                )
4251            });
4252            result.extend(multibuffer_indents);
4253        }
4254
4255        result
4256    }
4257
4258    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4259        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4260            let mut size = buffer.indent_size_for_line(range.start.row);
4261            size.len = size
4262                .len
4263                .min(range.end.column)
4264                .saturating_sub(range.start.column);
4265            size
4266        } else {
4267            IndentSize::spaces(0)
4268        }
4269    }
4270
4271    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4272        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4273            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4274        } else {
4275            LineIndent::spaces(0)
4276        }
4277    }
4278
4279    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4280        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4281
4282        if self.language_settings(cx).extend_comment_on_newline {
4283            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4284                let delimiters = language_scope.line_comment_prefixes();
4285                for delimiter in delimiters {
4286                    if *self
4287                        .chars_at(Point::new(row.0, indent.len() as u32))
4288                        .take(delimiter.chars().count())
4289                        .collect::<String>()
4290                        .as_str()
4291                        == **delimiter
4292                    {
4293                        indent.push_str(&delimiter);
4294                        break;
4295                    }
4296                }
4297            }
4298        }
4299
4300        indent
4301    }
4302
4303    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4304    where
4305        T: ToOffset,
4306    {
4307        for char in self.reversed_chars_at(position) {
4308            if !char.is_whitespace() {
4309                return false;
4310            }
4311            if char == '\n' {
4312                return true;
4313            }
4314        }
4315        return true;
4316    }
4317
4318    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4319        while row.0 > 0 {
4320            row.0 -= 1;
4321            if !self.is_line_blank(row) {
4322                return Some(row);
4323            }
4324        }
4325        None
4326    }
4327
4328    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4329        if let Some((_, range)) = self.buffer_line_for_row(row) {
4330            range.end.column - range.start.column
4331        } else {
4332            0
4333        }
4334    }
4335
4336    pub fn buffer_line_for_row(
4337        &self,
4338        row: MultiBufferRow,
4339    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4340        let mut cursor = self.cursor::<Point>();
4341        let point = Point::new(row.0, 0);
4342        cursor.seek(&point);
4343        let region = cursor.region()?;
4344        let overshoot = point.min(region.range.end) - region.range.start;
4345        let buffer_point = region.buffer_range.start + overshoot;
4346        if buffer_point.row > region.buffer_range.end.row {
4347            return None;
4348        }
4349        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4350        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4351            .min(region.buffer_range.end);
4352        Some((region.buffer, line_start..line_end))
4353    }
4354
4355    pub fn max_point(&self) -> Point {
4356        self.text_summary().lines
4357    }
4358
4359    pub fn max_row(&self) -> MultiBufferRow {
4360        MultiBufferRow(self.text_summary().lines.row)
4361    }
4362
4363    pub fn text_summary(&self) -> TextSummary {
4364        self.diff_transforms.summary().output
4365    }
4366
4367    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4368    where
4369        D: TextDimension,
4370        O: ToOffset,
4371    {
4372        let range = range.start.to_offset(self)..range.end.to_offset(self);
4373        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4374        cursor.seek(&range.start, Bias::Right, &());
4375
4376        let Some(first_transform) = cursor.item() else {
4377            return D::from_text_summary(&TextSummary::default());
4378        };
4379
4380        let diff_transform_start = cursor.start().0;
4381        let diff_transform_end = cursor.end(&()).0;
4382        let diff_start = range.start;
4383        let start_overshoot = diff_start - diff_transform_start;
4384        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4385
4386        let mut result = match first_transform {
4387            DiffTransform::BufferContent { .. } => {
4388                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4389                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4390                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4391            }
4392            DiffTransform::DeletedHunk {
4393                buffer_id,
4394                base_text_byte_range,
4395                has_trailing_newline,
4396                ..
4397            } => {
4398                let buffer_start = base_text_byte_range.start + start_overshoot;
4399                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4400                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4401                    panic!("{:?} is in non-existent deleted hunk", range.start)
4402                };
4403
4404                let include_trailing_newline =
4405                    *has_trailing_newline && range.end >= diff_transform_end;
4406                if include_trailing_newline {
4407                    buffer_end -= 1;
4408                }
4409
4410                let mut summary =
4411                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4412
4413                if include_trailing_newline {
4414                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4415                }
4416
4417                summary
4418            }
4419        };
4420        if range.end < diff_transform_end {
4421            return result;
4422        }
4423
4424        cursor.next(&());
4425        result.add_assign(&D::from_text_summary(&cursor.summary(
4426            &range.end,
4427            Bias::Right,
4428            &(),
4429        )));
4430
4431        let Some(last_transform) = cursor.item() else {
4432            return result;
4433        };
4434
4435        let overshoot = range.end - cursor.start().0;
4436        let suffix = match last_transform {
4437            DiffTransform::BufferContent { .. } => {
4438                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4439                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4440            }
4441            DiffTransform::DeletedHunk {
4442                base_text_byte_range,
4443                buffer_id,
4444                has_trailing_newline,
4445                ..
4446            } => {
4447                let buffer_end = base_text_byte_range.start + overshoot;
4448                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4449                    panic!("{:?} is in non-existent deleted hunk", range.end)
4450                };
4451
4452                let mut suffix = base_text
4453                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4454                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4455                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4456                }
4457                suffix
4458            }
4459        };
4460
4461        result.add_assign(&suffix);
4462        result
4463    }
4464
4465    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4466    where
4467        D: TextDimension,
4468    {
4469        // let mut range = range.start..range.end;
4470        let mut summary = D::zero(&());
4471        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4472        cursor.seek(&range.start, Bias::Right, &());
4473        if let Some(excerpt) = cursor.item() {
4474            let mut end_before_newline = cursor.end(&());
4475            if excerpt.has_trailing_newline {
4476                end_before_newline -= ExcerptOffset::new(1);
4477            }
4478
4479            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4480            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4481            let end_in_excerpt =
4482                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4483            summary.add_assign(
4484                &excerpt
4485                    .buffer
4486                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4487            );
4488
4489            if range.end > end_before_newline {
4490                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4491            }
4492
4493            cursor.next(&());
4494        }
4495
4496        if range.end > *cursor.start() {
4497            summary.add_assign(
4498                &cursor
4499                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4500                    .0,
4501            );
4502            if let Some(excerpt) = cursor.item() {
4503                range.end = cmp::max(*cursor.start(), range.end);
4504
4505                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4506                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4507                summary.add_assign(
4508                    &excerpt
4509                        .buffer
4510                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4511                );
4512            }
4513        }
4514
4515        summary
4516    }
4517
4518    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4519    where
4520        D: TextDimension + Ord + Sub<D, Output = D>,
4521    {
4522        self.summaries_for_anchors([anchor])[0]
4523    }
4524
4525    fn resolve_summary_for_anchor<D>(
4526        &self,
4527        anchor: &Anchor,
4528        excerpt_position: D,
4529        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4530    ) -> D
4531    where
4532        D: TextDimension + Ord + Sub<D, Output = D>,
4533    {
4534        loop {
4535            let transform_end_position = diff_transforms.end(&()).0 .0;
4536            let at_transform_end =
4537                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4538            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4539                diff_transforms.next(&());
4540                continue;
4541            }
4542
4543            let mut position = diff_transforms.start().1 .0;
4544            match diff_transforms.item() {
4545                Some(DiffTransform::DeletedHunk {
4546                    buffer_id,
4547                    base_text_byte_range,
4548                    ..
4549                }) => {
4550                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4551                        if let Some(base_text) =
4552                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4553                        {
4554                            if base_text.can_resolve(&diff_base_anchor) {
4555                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4556                                if base_text_offset >= base_text_byte_range.start
4557                                    && base_text_offset <= base_text_byte_range.end
4558                                {
4559                                    let position_in_hunk = base_text
4560                                        .text_summary_for_range::<D, _>(
4561                                            base_text_byte_range.start..base_text_offset,
4562                                        );
4563                                    position.add_assign(&position_in_hunk);
4564                                } else if at_transform_end {
4565                                    diff_transforms.next(&());
4566                                    continue;
4567                                }
4568                            }
4569                        }
4570                    }
4571                }
4572                _ => {
4573                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4574                        diff_transforms.next(&());
4575                        continue;
4576                    }
4577                    let overshoot = excerpt_position - diff_transforms.start().0 .0;
4578                    position.add_assign(&overshoot);
4579                }
4580            }
4581
4582            return position;
4583        }
4584    }
4585
4586    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4587        let mut cursor = self
4588            .excerpts
4589            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4590        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4591
4592        cursor.seek(&Some(locator), Bias::Left, &());
4593        if cursor.item().is_none() {
4594            cursor.next(&());
4595        }
4596
4597        let mut position = cursor.start().1;
4598        if let Some(excerpt) = cursor.item() {
4599            if excerpt.id == anchor.excerpt_id {
4600                let excerpt_buffer_start = excerpt
4601                    .buffer
4602                    .offset_for_anchor(&excerpt.range.context.start);
4603                let excerpt_buffer_end =
4604                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4605                let buffer_position = cmp::min(
4606                    excerpt_buffer_end,
4607                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4608                );
4609                if buffer_position > excerpt_buffer_start {
4610                    position.value += buffer_position - excerpt_buffer_start;
4611                }
4612            }
4613        }
4614        position
4615    }
4616
4617    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4618    where
4619        D: TextDimension + Ord + Sub<D, Output = D>,
4620        I: 'a + IntoIterator<Item = &'a Anchor>,
4621    {
4622        let mut anchors = anchors.into_iter().peekable();
4623        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4624        let mut diff_transforms_cursor = self
4625            .diff_transforms
4626            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4627        diff_transforms_cursor.next(&());
4628
4629        let mut summaries = Vec::new();
4630        while let Some(anchor) = anchors.peek() {
4631            let excerpt_id = anchor.excerpt_id;
4632            let excerpt_anchors = iter::from_fn(|| {
4633                let anchor = anchors.peek()?;
4634                if anchor.excerpt_id == excerpt_id {
4635                    Some(anchors.next().unwrap())
4636                } else {
4637                    None
4638                }
4639            });
4640
4641            let locator = self.excerpt_locator_for_id(excerpt_id);
4642            cursor.seek_forward(locator, Bias::Left, &());
4643            if cursor.item().is_none() {
4644                cursor.next(&());
4645            }
4646
4647            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4648            if let Some(excerpt) = cursor.item() {
4649                if excerpt.id != excerpt_id {
4650                    let position = self.resolve_summary_for_anchor(
4651                        &Anchor::min(),
4652                        excerpt_start_position,
4653                        &mut diff_transforms_cursor,
4654                    );
4655                    summaries.extend(excerpt_anchors.map(|_| position));
4656                    continue;
4657                }
4658                let excerpt_buffer_start =
4659                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4660                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4661                for (buffer_summary, anchor) in excerpt
4662                    .buffer
4663                    .summaries_for_anchors_with_payload::<D, _, _>(
4664                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4665                    )
4666                {
4667                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4668                    let mut position = excerpt_start_position;
4669                    if summary > excerpt_buffer_start {
4670                        position.add_assign(&(summary - excerpt_buffer_start));
4671                    }
4672
4673                    if position > diff_transforms_cursor.start().0 .0 {
4674                        diff_transforms_cursor.seek_forward(
4675                            &ExcerptDimension(position),
4676                            Bias::Left,
4677                            &(),
4678                        );
4679                    }
4680
4681                    summaries.push(self.resolve_summary_for_anchor(
4682                        anchor,
4683                        position,
4684                        &mut diff_transforms_cursor,
4685                    ));
4686                }
4687            } else {
4688                diff_transforms_cursor.seek_forward(
4689                    &ExcerptDimension(excerpt_start_position),
4690                    Bias::Left,
4691                    &(),
4692                );
4693                let position = self.resolve_summary_for_anchor(
4694                    &Anchor::max(),
4695                    excerpt_start_position,
4696                    &mut diff_transforms_cursor,
4697                );
4698                summaries.extend(excerpt_anchors.map(|_| position));
4699            }
4700        }
4701
4702        summaries
4703    }
4704
4705    pub fn dimensions_from_points<'a, D>(
4706        &'a self,
4707        points: impl 'a + IntoIterator<Item = Point>,
4708    ) -> impl 'a + Iterator<Item = D>
4709    where
4710        D: TextDimension + Sub<D, Output = D>,
4711    {
4712        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4713        cursor.seek(&DimensionPair {
4714            key: Point::default(),
4715            value: None,
4716        });
4717        let mut points = points.into_iter();
4718        iter::from_fn(move || {
4719            let point = points.next()?;
4720
4721            cursor.seek_forward(&DimensionPair {
4722                key: point,
4723                value: None,
4724            });
4725
4726            if let Some(region) = cursor.region() {
4727                let overshoot = point - region.range.start.key;
4728                let buffer_point = region.buffer_range.start.key + overshoot;
4729                let mut position = region.range.start.value.unwrap();
4730                position.add_assign(
4731                    &region
4732                        .buffer
4733                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4734                );
4735                return Some(position);
4736            } else {
4737                return Some(D::from_text_summary(&self.text_summary()));
4738            }
4739        })
4740    }
4741
4742    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4743    where
4744        I: 'a + IntoIterator<Item = &'a Anchor>,
4745    {
4746        let mut anchors = anchors.into_iter().enumerate().peekable();
4747        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4748        cursor.next(&());
4749
4750        let mut result = Vec::new();
4751
4752        while let Some((_, anchor)) = anchors.peek() {
4753            let old_excerpt_id = anchor.excerpt_id;
4754
4755            // Find the location where this anchor's excerpt should be.
4756            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4757            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4758
4759            if cursor.item().is_none() {
4760                cursor.next(&());
4761            }
4762
4763            let next_excerpt = cursor.item();
4764            let prev_excerpt = cursor.prev_item();
4765
4766            // Process all of the anchors for this excerpt.
4767            while let Some((_, anchor)) = anchors.peek() {
4768                if anchor.excerpt_id != old_excerpt_id {
4769                    break;
4770                }
4771                let (anchor_ix, anchor) = anchors.next().unwrap();
4772                let mut anchor = *anchor;
4773
4774                // Leave min and max anchors unchanged if invalid or
4775                // if the old excerpt still exists at this location
4776                let mut kept_position = next_excerpt
4777                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
4778                    || old_excerpt_id == ExcerptId::max()
4779                    || old_excerpt_id == ExcerptId::min();
4780
4781                // If the old excerpt no longer exists at this location, then attempt to
4782                // find an equivalent position for this anchor in an adjacent excerpt.
4783                if !kept_position {
4784                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4785                        if excerpt.contains(&anchor) {
4786                            anchor.excerpt_id = excerpt.id;
4787                            kept_position = true;
4788                            break;
4789                        }
4790                    }
4791                }
4792
4793                // If there's no adjacent excerpt that contains the anchor's position,
4794                // then report that the anchor has lost its position.
4795                if !kept_position {
4796                    anchor = if let Some(excerpt) = next_excerpt {
4797                        let mut text_anchor = excerpt
4798                            .range
4799                            .context
4800                            .start
4801                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4802                        if text_anchor
4803                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4804                            .is_gt()
4805                        {
4806                            text_anchor = excerpt.range.context.end;
4807                        }
4808                        Anchor {
4809                            buffer_id: Some(excerpt.buffer_id),
4810                            excerpt_id: excerpt.id,
4811                            text_anchor,
4812                            diff_base_anchor: None,
4813                        }
4814                    } else if let Some(excerpt) = prev_excerpt {
4815                        let mut text_anchor = excerpt
4816                            .range
4817                            .context
4818                            .end
4819                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4820                        if text_anchor
4821                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4822                            .is_lt()
4823                        {
4824                            text_anchor = excerpt.range.context.start;
4825                        }
4826                        Anchor {
4827                            buffer_id: Some(excerpt.buffer_id),
4828                            excerpt_id: excerpt.id,
4829                            text_anchor,
4830                            diff_base_anchor: None,
4831                        }
4832                    } else if anchor.text_anchor.bias == Bias::Left {
4833                        Anchor::min()
4834                    } else {
4835                        Anchor::max()
4836                    };
4837                }
4838
4839                result.push((anchor_ix, anchor, kept_position));
4840            }
4841        }
4842        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4843        result
4844    }
4845
4846    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4847        self.anchor_at(position, Bias::Left)
4848    }
4849
4850    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4851        self.anchor_at(position, Bias::Right)
4852    }
4853
4854    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4855        let offset = position.to_offset(self);
4856
4857        // Find the given position in the diff transforms. Determine the corresponding
4858        // offset in the excerpts, and whether the position is within a deleted hunk.
4859        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4860        diff_transforms.seek(&offset, Bias::Right, &());
4861
4862        if offset == diff_transforms.start().0 && bias == Bias::Left {
4863            if let Some(prev_item) = diff_transforms.prev_item() {
4864                match prev_item {
4865                    DiffTransform::DeletedHunk { .. } => {
4866                        diff_transforms.prev(&());
4867                    }
4868                    _ => {}
4869                }
4870            }
4871        }
4872        let offset_in_transform = offset - diff_transforms.start().0;
4873        let mut excerpt_offset = diff_transforms.start().1;
4874        let mut diff_base_anchor = None;
4875        if let Some(DiffTransform::DeletedHunk {
4876            buffer_id,
4877            base_text_byte_range,
4878            has_trailing_newline,
4879            ..
4880        }) = diff_transforms.item()
4881        {
4882            let diff = self.diffs.get(buffer_id).expect("missing diff");
4883            if offset_in_transform > base_text_byte_range.len() {
4884                debug_assert!(*has_trailing_newline);
4885                bias = Bias::Right;
4886            } else {
4887                diff_base_anchor = Some(
4888                    diff.base_text()
4889                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4890                );
4891                bias = Bias::Left;
4892            }
4893        } else {
4894            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4895        };
4896
4897        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
4898            return Anchor {
4899                buffer_id: Some(buffer_id),
4900                excerpt_id: *excerpt_id,
4901                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
4902                diff_base_anchor,
4903            };
4904        }
4905
4906        let mut excerpts = self
4907            .excerpts
4908            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
4909        excerpts.seek(&excerpt_offset, Bias::Right, &());
4910        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4911            excerpts.prev(&());
4912        }
4913        if let Some(excerpt) = excerpts.item() {
4914            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4915            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
4916                overshoot -= 1;
4917                bias = Bias::Right;
4918            }
4919
4920            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4921            let text_anchor =
4922                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4923            Anchor {
4924                buffer_id: Some(excerpt.buffer_id),
4925                excerpt_id: excerpt.id,
4926                text_anchor,
4927                diff_base_anchor,
4928            }
4929        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4930            Anchor::min()
4931        } else {
4932            Anchor::max()
4933        }
4934    }
4935
4936    /// Returns an anchor for the given excerpt and text anchor,
4937    /// returns None if the excerpt_id is no longer valid.
4938    pub fn anchor_in_excerpt(
4939        &self,
4940        excerpt_id: ExcerptId,
4941        text_anchor: text::Anchor,
4942    ) -> Option<Anchor> {
4943        let locator = self.excerpt_locator_for_id(excerpt_id);
4944        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4945        cursor.seek(locator, Bias::Left, &());
4946        if let Some(excerpt) = cursor.item() {
4947            if excerpt.id == excerpt_id {
4948                let text_anchor = excerpt.clip_anchor(text_anchor);
4949                drop(cursor);
4950                return Some(Anchor {
4951                    buffer_id: Some(excerpt.buffer_id),
4952                    excerpt_id,
4953                    text_anchor,
4954                    diff_base_anchor: None,
4955                });
4956            }
4957        }
4958        None
4959    }
4960
4961    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4962        Some(self.excerpt(excerpt_id)?.range.context.clone())
4963    }
4964
4965    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4966        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4967            true
4968        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4969            excerpt.buffer.can_resolve(&anchor.text_anchor)
4970        } else {
4971            false
4972        }
4973    }
4974
4975    pub fn excerpts(
4976        &self,
4977    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4978        self.excerpts
4979            .iter()
4980            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4981    }
4982
4983    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
4984        let excerpts = self.excerpts.cursor(&());
4985        let diff_transforms = self.diff_transforms.cursor(&());
4986        MultiBufferCursor {
4987            excerpts,
4988            diff_transforms,
4989            diffs: &self.diffs,
4990            cached_region: None,
4991        }
4992    }
4993
4994    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4995        let start_locator = self.excerpt_locator_for_id(id);
4996        let mut excerpts = self
4997            .excerpts
4998            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
4999        excerpts.seek(&Some(start_locator), Bias::Left, &());
5000        excerpts.prev(&());
5001
5002        let mut diff_transforms = self
5003            .diff_transforms
5004            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5005        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5006        if diff_transforms.end(&()).1 < excerpts.start().1 {
5007            diff_transforms.next(&());
5008        }
5009
5010        let excerpt = excerpts.item()?;
5011        Some(MultiBufferExcerpt {
5012            excerpt,
5013            offset: diff_transforms.start().0 .0,
5014            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5015            excerpt_offset: excerpts.start().1.clone(),
5016            diff_transforms,
5017        })
5018    }
5019
5020    pub fn excerpt_boundaries_in_range<R, T>(
5021        &self,
5022        range: R,
5023    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5024    where
5025        R: RangeBounds<T>,
5026        T: ToOffset,
5027    {
5028        let start_offset;
5029        let start = match range.start_bound() {
5030            Bound::Included(start) => {
5031                start_offset = start.to_offset(self);
5032                Bound::Included(start_offset)
5033            }
5034            Bound::Excluded(_) => {
5035                panic!("not supported")
5036            }
5037            Bound::Unbounded => {
5038                start_offset = 0;
5039                Bound::Unbounded
5040            }
5041        };
5042        let end = match range.end_bound() {
5043            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5044            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5045            Bound::Unbounded => Bound::Unbounded,
5046        };
5047        let bounds = (start, end);
5048
5049        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5050        cursor.seek(&DimensionPair {
5051            key: start_offset,
5052            value: None,
5053        });
5054
5055        if cursor
5056            .region()
5057            .is_some_and(|region| bounds.contains(&region.range.start.key))
5058        {
5059            cursor.prev_excerpt();
5060        } else {
5061            cursor.seek_to_start_of_current_excerpt();
5062        }
5063        let mut prev_region = cursor.region();
5064
5065        cursor.next_excerpt();
5066
5067        let mut visited_end = false;
5068        iter::from_fn(move || loop {
5069            if self.singleton {
5070                return None;
5071            }
5072
5073            let next_region = cursor.region();
5074            cursor.next_excerpt();
5075
5076            let next_region_start = if let Some(region) = &next_region {
5077                if !bounds.contains(&region.range.start.key) {
5078                    prev_region = next_region;
5079                    continue;
5080                }
5081                region.range.start.value.unwrap()
5082            } else {
5083                if !bounds.contains(&self.len()) {
5084                    return None;
5085                }
5086                self.max_point()
5087            };
5088            let next_region_end = if let Some(region) = cursor.region() {
5089                region.range.start.value.unwrap()
5090            } else {
5091                self.max_point()
5092            };
5093
5094            let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5095                id: region.excerpt.id,
5096                buffer: region.excerpt.buffer.clone(),
5097                buffer_id: region.excerpt.buffer_id,
5098                range: region.excerpt.range.clone(),
5099                end_row: MultiBufferRow(next_region_start.row),
5100            });
5101
5102            let next = next_region.as_ref().map(|region| ExcerptInfo {
5103                id: region.excerpt.id,
5104                buffer: region.excerpt.buffer.clone(),
5105                buffer_id: region.excerpt.buffer_id,
5106                range: region.excerpt.range.clone(),
5107                end_row: if region.excerpt.has_trailing_newline {
5108                    MultiBufferRow(next_region_end.row - 1)
5109                } else {
5110                    MultiBufferRow(next_region_end.row)
5111                },
5112            });
5113
5114            if next.is_none() {
5115                if visited_end {
5116                    return None;
5117                } else {
5118                    visited_end = true;
5119                }
5120            }
5121
5122            let row = MultiBufferRow(next_region_start.row);
5123
5124            prev_region = next_region;
5125
5126            return Some(ExcerptBoundary { row, prev, next });
5127        })
5128    }
5129
5130    pub fn edit_count(&self) -> usize {
5131        self.edit_count
5132    }
5133
5134    pub fn non_text_state_update_count(&self) -> usize {
5135        self.non_text_state_update_count
5136    }
5137
5138    /// Returns the smallest enclosing bracket ranges containing the given range or
5139    /// None if no brackets contain range or the range is not contained in a single
5140    /// excerpt
5141    ///
5142    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5143    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5144        &self,
5145        range: Range<T>,
5146        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5147    ) -> Option<(Range<usize>, Range<usize>)> {
5148        let range = range.start.to_offset(self)..range.end.to_offset(self);
5149        let mut excerpt = self.excerpt_containing(range.clone())?;
5150        let buffer = excerpt.buffer();
5151        let excerpt_buffer_range = excerpt.buffer_range();
5152
5153        // Filter to ranges contained in the excerpt
5154        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5155            excerpt_buffer_range.contains(&open.start)
5156                && excerpt_buffer_range.contains(&close.end)
5157                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5158        };
5159
5160        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5161            excerpt.map_range_to_buffer(range),
5162            Some(&range_filter),
5163        )?;
5164
5165        Some((
5166            excerpt.map_range_from_buffer(open),
5167            excerpt.map_range_from_buffer(close),
5168        ))
5169    }
5170
5171    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5172    /// not contained in a single excerpt
5173    pub fn enclosing_bracket_ranges<T: ToOffset>(
5174        &self,
5175        range: Range<T>,
5176    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5177        let range = range.start.to_offset(self)..range.end.to_offset(self);
5178        let mut excerpt = self.excerpt_containing(range.clone())?;
5179
5180        Some(
5181            excerpt
5182                .buffer()
5183                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5184                .filter_map(move |pair| {
5185                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5186                        Some((
5187                            excerpt.map_range_from_buffer(pair.open_range),
5188                            excerpt.map_range_from_buffer(pair.close_range),
5189                        ))
5190                    } else {
5191                        None
5192                    }
5193                }),
5194        )
5195    }
5196
5197    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5198    /// not contained in a single excerpt
5199    pub fn text_object_ranges<T: ToOffset>(
5200        &self,
5201        range: Range<T>,
5202        options: TreeSitterOptions,
5203    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5204        let range = range.start.to_offset(self)..range.end.to_offset(self);
5205        self.excerpt_containing(range.clone())
5206            .map(|mut excerpt| {
5207                excerpt
5208                    .buffer()
5209                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5210                    .filter_map(move |(range, text_object)| {
5211                        if excerpt.contains_buffer_range(range.clone()) {
5212                            Some((excerpt.map_range_from_buffer(range), text_object))
5213                        } else {
5214                            None
5215                        }
5216                    })
5217            })
5218            .into_iter()
5219            .flatten()
5220    }
5221
5222    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5223    /// not contained in a single excerpt
5224    pub fn bracket_ranges<T: ToOffset>(
5225        &self,
5226        range: Range<T>,
5227    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5228        let range = range.start.to_offset(self)..range.end.to_offset(self);
5229        let mut excerpt = self.excerpt_containing(range.clone())?;
5230
5231        Some(
5232            excerpt
5233                .buffer()
5234                .bracket_ranges(excerpt.map_range_to_buffer(range))
5235                .filter_map(move |pair| {
5236                    let buffer_range = pair.open_range.start..pair.close_range.end;
5237                    if excerpt.contains_buffer_range(buffer_range) {
5238                        Some((
5239                            excerpt.map_range_from_buffer(pair.open_range),
5240                            excerpt.map_range_from_buffer(pair.close_range),
5241                        ))
5242                    } else {
5243                        None
5244                    }
5245                }),
5246        )
5247    }
5248
5249    pub fn redacted_ranges<'a, T: ToOffset>(
5250        &'a self,
5251        range: Range<T>,
5252        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5253    ) -> impl Iterator<Item = Range<usize>> + 'a {
5254        let range = range.start.to_offset(self)..range.end.to_offset(self);
5255        self.lift_buffer_metadata(range, move |buffer, range| {
5256            if redaction_enabled(buffer.file()) {
5257                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5258            } else {
5259                None
5260            }
5261        })
5262        .map(|(range, _, _)| range)
5263    }
5264
5265    pub fn runnable_ranges(
5266        &self,
5267        range: Range<Anchor>,
5268    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5269        let range = range.start.to_offset(self)..range.end.to_offset(self);
5270        self.lift_buffer_metadata(range, move |buffer, range| {
5271            Some(
5272                buffer
5273                    .runnable_ranges(range.clone())
5274                    .filter(move |runnable| {
5275                        runnable.run_range.start >= range.start
5276                            && runnable.run_range.end < range.end
5277                    })
5278                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5279            )
5280        })
5281        .map(|(run_range, runnable, _)| language::RunnableRange {
5282            run_range,
5283            ..runnable
5284        })
5285    }
5286
5287    pub fn line_indents(
5288        &self,
5289        start_row: MultiBufferRow,
5290        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5291    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5292        let max_point = self.max_point();
5293        let mut cursor = self.cursor::<Point>();
5294        cursor.seek(&Point::new(start_row.0, 0));
5295        iter::from_fn(move || {
5296            let mut region = cursor.region()?;
5297            while !buffer_filter(&region.excerpt.buffer) {
5298                cursor.next();
5299                region = cursor.region()?;
5300            }
5301            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5302            let buffer_start_row =
5303                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5304
5305            let buffer_end_row = if region.is_main_buffer
5306                && (region.has_trailing_newline || region.range.end == max_point)
5307            {
5308                region.buffer_range.end.row
5309            } else {
5310                region.buffer_range.end.row.saturating_sub(1)
5311            };
5312
5313            let line_indents = region
5314                .buffer
5315                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5316            cursor.next();
5317            return Some(line_indents.map(move |(buffer_row, indent)| {
5318                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5319                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5320            }));
5321        })
5322        .flatten()
5323    }
5324
5325    pub fn reversed_line_indents(
5326        &self,
5327        end_row: MultiBufferRow,
5328        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5329    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5330        let max_point = self.max_point();
5331        let mut cursor = self.cursor::<Point>();
5332        cursor.seek(&Point::new(end_row.0, 0));
5333        iter::from_fn(move || {
5334            let mut region = cursor.region()?;
5335            while !buffer_filter(&region.excerpt.buffer) {
5336                cursor.prev();
5337                region = cursor.region()?;
5338            }
5339
5340            let buffer_start_row = region.buffer_range.start.row;
5341            let buffer_end_row = if region.is_main_buffer
5342                && (region.has_trailing_newline || region.range.end == max_point)
5343            {
5344                region.buffer_range.end.row + 1
5345            } else {
5346                region.buffer_range.end.row
5347            };
5348
5349            let overshoot = end_row.0 - region.range.start.row;
5350            let buffer_end_row =
5351                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5352
5353            let line_indents = region
5354                .buffer
5355                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5356            cursor.prev();
5357            return Some(line_indents.map(move |(buffer_row, indent)| {
5358                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5359                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5360            }));
5361        })
5362        .flatten()
5363    }
5364
5365    pub async fn enclosing_indent(
5366        &self,
5367        mut target_row: MultiBufferRow,
5368    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5369        let max_row = MultiBufferRow(self.max_point().row);
5370        if target_row >= max_row {
5371            return None;
5372        }
5373
5374        let mut target_indent = self.line_indent_for_row(target_row);
5375
5376        // If the current row is at the start of an indented block, we want to return this
5377        // block as the enclosing indent.
5378        if !target_indent.is_line_empty() && target_row < max_row {
5379            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5380            if !next_line_indent.is_line_empty()
5381                && target_indent.raw_len() < next_line_indent.raw_len()
5382            {
5383                target_indent = next_line_indent;
5384                target_row.0 += 1;
5385            }
5386        }
5387
5388        const SEARCH_ROW_LIMIT: u32 = 25000;
5389        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5390        const YIELD_INTERVAL: u32 = 100;
5391
5392        let mut accessed_row_counter = 0;
5393
5394        // If there is a blank line at the current row, search for the next non indented lines
5395        if target_indent.is_line_empty() {
5396            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5397            let end =
5398                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5399
5400            let mut non_empty_line_above = None;
5401            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5402                if row < start {
5403                    break;
5404                }
5405                accessed_row_counter += 1;
5406                if accessed_row_counter == YIELD_INTERVAL {
5407                    accessed_row_counter = 0;
5408                    yield_now().await;
5409                }
5410                if !indent.is_line_empty() {
5411                    non_empty_line_above = Some((row, indent));
5412                    break;
5413                }
5414            }
5415
5416            let mut non_empty_line_below = None;
5417            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5418                if row > end {
5419                    break;
5420                }
5421                accessed_row_counter += 1;
5422                if accessed_row_counter == YIELD_INTERVAL {
5423                    accessed_row_counter = 0;
5424                    yield_now().await;
5425                }
5426                if !indent.is_line_empty() {
5427                    non_empty_line_below = Some((row, indent));
5428                    break;
5429                }
5430            }
5431
5432            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5433                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5434                    if above_indent.raw_len() >= below_indent.raw_len() {
5435                        (above_row, above_indent)
5436                    } else {
5437                        (below_row, below_indent)
5438                    }
5439                }
5440                (Some(above), None) => above,
5441                (None, Some(below)) => below,
5442                _ => return None,
5443            };
5444
5445            target_indent = indent;
5446            target_row = row;
5447        }
5448
5449        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5450        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5451
5452        let mut start_indent = None;
5453        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5454            if row < start {
5455                break;
5456            }
5457            accessed_row_counter += 1;
5458            if accessed_row_counter == YIELD_INTERVAL {
5459                accessed_row_counter = 0;
5460                yield_now().await;
5461            }
5462            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5463                start_indent = Some((row, indent));
5464                break;
5465            }
5466        }
5467        let (start_row, start_indent_size) = start_indent?;
5468
5469        let mut end_indent = (end, None);
5470        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5471            if row > end {
5472                break;
5473            }
5474            accessed_row_counter += 1;
5475            if accessed_row_counter == YIELD_INTERVAL {
5476                accessed_row_counter = 0;
5477                yield_now().await;
5478            }
5479            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5480                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5481                break;
5482            }
5483        }
5484        let (end_row, end_indent_size) = end_indent;
5485
5486        let indent = if let Some(end_indent_size) = end_indent_size {
5487            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5488                start_indent_size
5489            } else {
5490                end_indent_size
5491            }
5492        } else {
5493            start_indent_size
5494        };
5495
5496        Some((start_row..end_row, indent))
5497    }
5498
5499    pub fn indent_guides_in_range<T: ToPoint>(
5500        &self,
5501        range: Range<T>,
5502        ignore_disabled_for_language: bool,
5503        cx: &App,
5504    ) -> impl Iterator<Item = IndentGuide> {
5505        let range = range.start.to_point(self)..range.end.to_point(self);
5506        let start_row = MultiBufferRow(range.start.row);
5507        let end_row = MultiBufferRow(range.end.row);
5508
5509        let mut row_indents = self.line_indents(start_row, |buffer| {
5510            let settings =
5511                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5512            settings.indent_guides.enabled || ignore_disabled_for_language
5513        });
5514
5515        let mut result = Vec::new();
5516        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5517
5518        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5519            if first_row > end_row {
5520                break;
5521            }
5522            let current_depth = indent_stack.len() as u32;
5523
5524            let settings =
5525                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5526            let tab_size = settings.tab_size.get() as u32;
5527
5528            // When encountering empty, continue until found useful line indent
5529            // then add to the indent stack with the depth found
5530            let mut found_indent = false;
5531            let mut last_row = first_row;
5532            if line_indent.is_line_empty() {
5533                while !found_indent {
5534                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5535                        break;
5536                    };
5537                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5538                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5539                        break;
5540                    }
5541
5542                    if new_line_indent.is_line_empty() {
5543                        continue;
5544                    }
5545                    last_row = target_row.min(end_row);
5546                    line_indent = new_line_indent;
5547                    found_indent = true;
5548                    break;
5549                }
5550            } else {
5551                found_indent = true
5552            }
5553
5554            let depth = if found_indent {
5555                line_indent.len(tab_size) / tab_size
5556                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5557            } else {
5558                current_depth
5559            };
5560
5561            match depth.cmp(&current_depth) {
5562                cmp::Ordering::Less => {
5563                    for _ in 0..(current_depth - depth) {
5564                        let mut indent = indent_stack.pop().unwrap();
5565                        if last_row != first_row {
5566                            // In this case, we landed on an empty row, had to seek forward,
5567                            // and discovered that the indent we where on is ending.
5568                            // This means that the last display row must
5569                            // be on line that ends this indent range, so we
5570                            // should display the range up to the first non-empty line
5571                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5572                        }
5573
5574                        result.push(indent)
5575                    }
5576                }
5577                cmp::Ordering::Greater => {
5578                    for next_depth in current_depth..depth {
5579                        indent_stack.push(IndentGuide {
5580                            buffer_id: buffer.remote_id(),
5581                            start_row: first_row,
5582                            end_row: last_row,
5583                            depth: next_depth,
5584                            tab_size,
5585                            settings: settings.indent_guides,
5586                        });
5587                    }
5588                }
5589                _ => {}
5590            }
5591
5592            for indent in indent_stack.iter_mut() {
5593                indent.end_row = last_row;
5594            }
5595        }
5596
5597        result.extend(indent_stack);
5598        result.into_iter()
5599    }
5600
5601    pub fn trailing_excerpt_update_count(&self) -> usize {
5602        self.trailing_excerpt_update_count
5603    }
5604
5605    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5606        self.point_to_buffer_offset(point)
5607            .and_then(|(buffer, _)| buffer.file())
5608    }
5609
5610    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5611        self.point_to_buffer_offset(point)
5612            .and_then(|(buffer, offset)| buffer.language_at(offset))
5613    }
5614
5615    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5616        self.excerpts
5617            .first()
5618            .map(|excerpt| &excerpt.buffer)
5619            .map(|buffer| {
5620                language_settings(
5621                    buffer.language().map(|language| language.name()),
5622                    buffer.file(),
5623                    cx,
5624                )
5625            })
5626            .unwrap_or_else(move || self.language_settings_at(0, cx))
5627    }
5628
5629    pub fn language_settings_at<'a, T: ToOffset>(
5630        &'a self,
5631        point: T,
5632        cx: &'a App,
5633    ) -> Cow<'a, LanguageSettings> {
5634        let mut language = None;
5635        let mut file = None;
5636        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5637            language = buffer.language_at(offset);
5638            file = buffer.file();
5639        }
5640        language_settings(language.map(|l| l.name()), file, cx)
5641    }
5642
5643    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5644        self.point_to_buffer_offset(point)
5645            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5646    }
5647
5648    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5649        self.point_to_buffer_offset(point)
5650            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5651            .unwrap_or_default()
5652    }
5653
5654    pub fn language_indent_size_at<T: ToOffset>(
5655        &self,
5656        position: T,
5657        cx: &App,
5658    ) -> Option<IndentSize> {
5659        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5660        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5661    }
5662
5663    pub fn is_dirty(&self) -> bool {
5664        self.is_dirty
5665    }
5666
5667    pub fn has_deleted_file(&self) -> bool {
5668        self.has_deleted_file
5669    }
5670
5671    pub fn has_conflict(&self) -> bool {
5672        self.has_conflict
5673    }
5674
5675    pub fn has_diagnostics(&self) -> bool {
5676        self.excerpts
5677            .iter()
5678            .any(|excerpt| excerpt.buffer.has_diagnostics())
5679    }
5680
5681    pub fn diagnostic_group(
5682        &self,
5683        buffer_id: BufferId,
5684        group_id: usize,
5685    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5686        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5687            if buffer.remote_id() != buffer_id {
5688                return None;
5689            };
5690            Some(
5691                buffer
5692                    .diagnostic_group(group_id)
5693                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5694            )
5695        })
5696        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5697    }
5698
5699    pub fn diagnostics_in_range<'a, T>(
5700        &'a self,
5701        range: Range<T>,
5702    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5703    where
5704        T: 'a
5705            + text::ToOffset
5706            + text::FromAnchor
5707            + TextDimension
5708            + Ord
5709            + Sub<T, Output = T>
5710            + fmt::Debug,
5711    {
5712        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5713            Some(
5714                buffer
5715                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5716                    .map(|entry| (entry.range, entry.diagnostic)),
5717            )
5718        })
5719        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5720    }
5721
5722    pub fn syntax_ancestor<T: ToOffset>(
5723        &self,
5724        range: Range<T>,
5725    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5726        let range = range.start.to_offset(self)..range.end.to_offset(self);
5727        let mut excerpt = self.excerpt_containing(range.clone())?;
5728        let node = excerpt
5729            .buffer()
5730            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5731        let node_range = node.byte_range();
5732        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5733            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5734        } else {
5735            MultiOrSingleBufferOffsetRange::Single(node_range)
5736        };
5737        Some((node, range))
5738    }
5739
5740    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5741        let (excerpt_id, _, buffer) = self.as_singleton()?;
5742        let outline = buffer.outline(theme)?;
5743        Some(Outline::new(
5744            outline
5745                .items
5746                .into_iter()
5747                .flat_map(|item| {
5748                    Some(OutlineItem {
5749                        depth: item.depth,
5750                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5751                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5752                        text: item.text,
5753                        highlight_ranges: item.highlight_ranges,
5754                        name_ranges: item.name_ranges,
5755                        body_range: item.body_range.and_then(|body_range| {
5756                            Some(
5757                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5758                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5759                            )
5760                        }),
5761                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5762                            Some(
5763                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5764                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5765                            )
5766                        }),
5767                    })
5768                })
5769                .collect(),
5770        ))
5771    }
5772
5773    pub fn symbols_containing<T: ToOffset>(
5774        &self,
5775        offset: T,
5776        theme: Option<&SyntaxTheme>,
5777    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5778        let anchor = self.anchor_before(offset);
5779        let excerpt_id = anchor.excerpt_id;
5780        let excerpt = self.excerpt(excerpt_id)?;
5781        Some((
5782            excerpt.buffer_id,
5783            excerpt
5784                .buffer
5785                .symbols_containing(anchor.text_anchor, theme)
5786                .into_iter()
5787                .flatten()
5788                .flat_map(|item| {
5789                    Some(OutlineItem {
5790                        depth: item.depth,
5791                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
5792                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
5793                        text: item.text,
5794                        highlight_ranges: item.highlight_ranges,
5795                        name_ranges: item.name_ranges,
5796                        body_range: item.body_range.and_then(|body_range| {
5797                            Some(
5798                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5799                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5800                            )
5801                        }),
5802                        annotation_range: item.annotation_range.and_then(|body_range| {
5803                            Some(
5804                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
5805                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
5806                            )
5807                        }),
5808                    })
5809                })
5810                .collect(),
5811        ))
5812    }
5813
5814    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5815        if id == ExcerptId::min() {
5816            Locator::min_ref()
5817        } else if id == ExcerptId::max() {
5818            Locator::max_ref()
5819        } else {
5820            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5821            cursor.seek(&id, Bias::Left, &());
5822            if let Some(entry) = cursor.item() {
5823                if entry.id == id {
5824                    return &entry.locator;
5825                }
5826            }
5827            panic!("invalid excerpt id {:?}", id)
5828        }
5829    }
5830
5831    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5832    fn excerpt_locators_for_ids(
5833        &self,
5834        ids: impl IntoIterator<Item = ExcerptId>,
5835    ) -> SmallVec<[Locator; 1]> {
5836        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5837        sorted_ids.sort_unstable();
5838        let mut locators = SmallVec::new();
5839
5840        while sorted_ids.last() == Some(&ExcerptId::max()) {
5841            sorted_ids.pop();
5842            if let Some(mapping) = self.excerpt_ids.last() {
5843                locators.push(mapping.locator.clone());
5844            }
5845        }
5846
5847        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
5848        if sorted_ids.peek() == Some(&ExcerptId::min()) {
5849            sorted_ids.next();
5850            if let Some(mapping) = self.excerpt_ids.first() {
5851                locators.push(mapping.locator.clone());
5852            }
5853        }
5854
5855        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
5856        for id in sorted_ids {
5857            if cursor.seek_forward(&id, Bias::Left, &()) {
5858                locators.push(cursor.item().unwrap().locator.clone());
5859            } else {
5860                panic!("invalid excerpt id {:?}", id);
5861            }
5862        }
5863
5864        locators.sort_unstable();
5865        locators
5866    }
5867
5868    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5869        Some(self.excerpt(excerpt_id)?.buffer_id)
5870    }
5871
5872    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5873        Some(&self.excerpt(excerpt_id)?.buffer)
5874    }
5875
5876    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5877        let mut cursor = self
5878            .excerpts
5879            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
5880        let locator = self.excerpt_locator_for_id(excerpt_id);
5881        if cursor.seek(&Some(locator), Bias::Left, &()) {
5882            let start = cursor.start().1.clone();
5883            let end = cursor.end(&()).1;
5884            let mut diff_transforms = self
5885                .diff_transforms
5886                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
5887            diff_transforms.seek(&start, Bias::Left, &());
5888            let overshoot = start.0 - diff_transforms.start().0 .0;
5889            let start = diff_transforms.start().1 .0 + overshoot;
5890            diff_transforms.seek(&end, Bias::Right, &());
5891            let overshoot = end.0 - diff_transforms.start().0 .0;
5892            let end = diff_transforms.start().1 .0 + overshoot;
5893            Some(start..end)
5894        } else {
5895            None
5896        }
5897    }
5898
5899    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5900        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5901        let locator = self.excerpt_locator_for_id(excerpt_id);
5902        if cursor.seek(&Some(locator), Bias::Left, &()) {
5903            if let Some(excerpt) = cursor.item() {
5904                return Some(excerpt.range.context.clone());
5905            }
5906        }
5907        None
5908    }
5909
5910    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5911        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5912        let locator = self.excerpt_locator_for_id(excerpt_id);
5913        cursor.seek(&Some(locator), Bias::Left, &());
5914        if let Some(excerpt) = cursor.item() {
5915            if excerpt.id == excerpt_id {
5916                return Some(excerpt);
5917            }
5918        }
5919        None
5920    }
5921
5922    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5923    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
5924        let range = range.start.to_offset(self)..range.end.to_offset(self);
5925        let mut cursor = self.cursor::<usize>();
5926        cursor.seek(&range.start);
5927
5928        let start_excerpt = cursor.excerpt()?;
5929        if range.end != range.start {
5930            cursor.seek_forward(&range.end);
5931            if cursor.excerpt()?.id != start_excerpt.id {
5932                return None;
5933            }
5934        }
5935
5936        cursor.seek_to_start_of_current_excerpt();
5937        let region = cursor.region()?;
5938        let offset = region.range.start;
5939        let buffer_offset = region.buffer_range.start;
5940        let excerpt_offset = cursor.excerpts.start().clone();
5941        Some(MultiBufferExcerpt {
5942            diff_transforms: cursor.diff_transforms,
5943            excerpt: start_excerpt,
5944            offset,
5945            buffer_offset,
5946            excerpt_offset,
5947        })
5948    }
5949
5950    pub fn selections_in_range<'a>(
5951        &'a self,
5952        range: &'a Range<Anchor>,
5953        include_local: bool,
5954    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5955        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
5956        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5957        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5958        cursor.seek(start_locator, Bias::Left, &());
5959        cursor
5960            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5961            .flat_map(move |excerpt| {
5962                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5963                if excerpt.id == range.start.excerpt_id {
5964                    query_range.start = range.start.text_anchor;
5965                }
5966                if excerpt.id == range.end.excerpt_id {
5967                    query_range.end = range.end.text_anchor;
5968                }
5969
5970                excerpt
5971                    .buffer
5972                    .selections_in_range(query_range, include_local)
5973                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5974                        selections.map(move |selection| {
5975                            let mut start = Anchor {
5976                                buffer_id: Some(excerpt.buffer_id),
5977                                excerpt_id: excerpt.id,
5978                                text_anchor: selection.start,
5979                                diff_base_anchor: None,
5980                            };
5981                            let mut end = Anchor {
5982                                buffer_id: Some(excerpt.buffer_id),
5983                                excerpt_id: excerpt.id,
5984                                text_anchor: selection.end,
5985                                diff_base_anchor: None,
5986                            };
5987                            if range.start.cmp(&start, self).is_gt() {
5988                                start = range.start;
5989                            }
5990                            if range.end.cmp(&end, self).is_lt() {
5991                                end = range.end;
5992                            }
5993
5994                            (
5995                                replica_id,
5996                                line_mode,
5997                                cursor_shape,
5998                                Selection {
5999                                    id: selection.id,
6000                                    start,
6001                                    end,
6002                                    reversed: selection.reversed,
6003                                    goal: selection.goal,
6004                                },
6005                            )
6006                        })
6007                    })
6008            })
6009    }
6010
6011    pub fn show_headers(&self) -> bool {
6012        self.show_headers
6013    }
6014
6015    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6016        self.diffs.get(&buffer_id)
6017    }
6018}
6019
6020#[cfg(any(test, feature = "test-support"))]
6021impl MultiBufferSnapshot {
6022    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6023        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6024        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6025        start..end
6026    }
6027
6028    #[cfg(any(test, feature = "test-support"))]
6029    fn check_invariants(&self) {
6030        let excerpts = self.excerpts.items(&());
6031        let excerpt_ids = self.excerpt_ids.items(&());
6032
6033        for (ix, excerpt) in excerpts.iter().enumerate() {
6034            if ix == 0 {
6035                if excerpt.locator <= Locator::min() {
6036                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6037                }
6038            } else if excerpt.locator <= excerpts[ix - 1].locator {
6039                panic!("excerpts are out-of-order: {:?}", excerpts);
6040            }
6041        }
6042
6043        for (ix, entry) in excerpt_ids.iter().enumerate() {
6044            if ix == 0 {
6045                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6046                    panic!("invalid first excerpt id {:?}", entry.id);
6047                }
6048            } else if entry.id <= excerpt_ids[ix - 1].id {
6049                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6050            }
6051        }
6052
6053        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6054            panic!(
6055                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6056                self.excerpts.summary().text.len,
6057                self.diff_transforms.summary().input,
6058                self.diff_transforms.items(&()),
6059            );
6060        }
6061
6062        let mut prev_transform: Option<&DiffTransform> = None;
6063        for item in self.diff_transforms.iter() {
6064            if let DiffTransform::BufferContent {
6065                summary,
6066                inserted_hunk_info,
6067            } = item
6068            {
6069                if let Some(DiffTransform::BufferContent {
6070                    inserted_hunk_info: prev_inserted_hunk_info,
6071                    ..
6072                }) = prev_transform
6073                {
6074                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6075                        panic!(
6076                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6077                            self.diff_transforms.items(&()));
6078                    }
6079                }
6080                if summary.len == 0 && !self.is_empty() {
6081                    panic!("empty buffer content transform");
6082                }
6083            }
6084            prev_transform = Some(item);
6085        }
6086    }
6087}
6088
6089impl<'a, D> MultiBufferCursor<'a, D>
6090where
6091    D: TextDimension + Ord + Sub<D, Output = D>,
6092{
6093    fn seek(&mut self, position: &D) {
6094        self.cached_region.take();
6095        self.diff_transforms
6096            .seek(&OutputDimension(*position), Bias::Right, &());
6097        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6098            self.diff_transforms.prev(&());
6099        }
6100
6101        let mut excerpt_position = self.diff_transforms.start().1 .0;
6102        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6103            let overshoot = *position - self.diff_transforms.start().0 .0;
6104            excerpt_position.add_assign(&overshoot);
6105        }
6106
6107        self.excerpts
6108            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6109        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6110            self.excerpts.prev(&());
6111        }
6112    }
6113
6114    fn seek_forward(&mut self, position: &D) {
6115        self.cached_region.take();
6116        self.diff_transforms
6117            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6118        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0 .0 {
6119            self.diff_transforms.prev(&());
6120        }
6121
6122        let overshoot = *position - self.diff_transforms.start().0 .0;
6123        let mut excerpt_position = self.diff_transforms.start().1 .0;
6124        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6125            excerpt_position.add_assign(&overshoot);
6126        }
6127
6128        self.excerpts
6129            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6130        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6131            self.excerpts.prev(&());
6132        }
6133    }
6134
6135    fn seek_to_buffer_position_in_current_excerpt(&mut self, position: &D) {
6136        self.cached_region.take();
6137        if let Some(excerpt) = self.excerpts.item() {
6138            let excerpt_start = excerpt.range.context.start.summary::<D>(&excerpt.buffer);
6139            let position_in_excerpt = *position - excerpt_start;
6140            let mut excerpt_position = self.excerpts.start().0;
6141            excerpt_position.add_assign(&position_in_excerpt);
6142            self.diff_transforms
6143                .seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
6144            if self.diff_transforms.item().is_none() {
6145                self.diff_transforms.next(&());
6146            }
6147        }
6148    }
6149
6150    fn next_excerpt(&mut self) {
6151        self.excerpts.next(&());
6152        self.seek_to_start_of_current_excerpt();
6153    }
6154
6155    fn prev_excerpt(&mut self) {
6156        self.excerpts.prev(&());
6157        self.seek_to_start_of_current_excerpt();
6158    }
6159
6160    fn seek_to_start_of_current_excerpt(&mut self) {
6161        self.cached_region.take();
6162        self.diff_transforms
6163            .seek(self.excerpts.start(), Bias::Left, &());
6164        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6165            && self.diff_transforms.start().1 < *self.excerpts.start()
6166            && self.diff_transforms.next_item().is_some()
6167        {
6168            self.diff_transforms.next(&());
6169        }
6170    }
6171
6172    fn next(&mut self) {
6173        self.cached_region.take();
6174        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6175            cmp::Ordering::Less => self.diff_transforms.next(&()),
6176            cmp::Ordering::Greater => self.excerpts.next(&()),
6177            cmp::Ordering::Equal => {
6178                self.diff_transforms.next(&());
6179                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6180                    || self.diff_transforms.item().is_none()
6181                {
6182                    self.excerpts.next(&());
6183                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6184                    self.diff_transforms.item()
6185                {
6186                    if self
6187                        .excerpts
6188                        .item()
6189                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6190                    {
6191                        self.excerpts.next(&());
6192                    }
6193                }
6194            }
6195        }
6196    }
6197
6198    fn prev(&mut self) {
6199        self.cached_region.take();
6200        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6201            cmp::Ordering::Less => self.excerpts.prev(&()),
6202            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6203            cmp::Ordering::Equal => {
6204                self.diff_transforms.prev(&());
6205                if self.diff_transforms.start().1 < *self.excerpts.start()
6206                    || self.diff_transforms.item().is_none()
6207                {
6208                    self.excerpts.prev(&());
6209                }
6210            }
6211        }
6212    }
6213
6214    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6215        if self.cached_region.is_none() {
6216            self.cached_region = self.build_region();
6217        }
6218        self.cached_region.clone()
6219    }
6220
6221    fn is_at_end_of_excerpt(&mut self) -> bool {
6222        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6223            return false;
6224        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6225            || self.diff_transforms.item().is_none()
6226        {
6227            return true;
6228        }
6229
6230        let next_transform = self.diff_transforms.next_item();
6231        next_transform.map_or(true, |next_transform| match next_transform {
6232            DiffTransform::BufferContent { .. } => true,
6233            DiffTransform::DeletedHunk { hunk_info, .. } => self
6234                .excerpts
6235                .item()
6236                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6237        })
6238    }
6239
6240    fn main_buffer_position(&self) -> Option<D> {
6241        let excerpt = self.excerpts.item()?;
6242        let buffer = &excerpt.buffer;
6243        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6244        let mut buffer_start = buffer_context_start;
6245        let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6246        buffer_start.add_assign(&overshoot);
6247        Some(buffer_start)
6248    }
6249
6250    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6251        let excerpt = self.excerpts.item()?;
6252        match self.diff_transforms.item()? {
6253            DiffTransform::DeletedHunk {
6254                buffer_id,
6255                base_text_byte_range,
6256                has_trailing_newline,
6257                hunk_info,
6258                ..
6259            } => {
6260                let diff = self.diffs.get(&buffer_id)?;
6261                let buffer = diff.base_text();
6262                let mut rope_cursor = buffer.as_rope().cursor(0);
6263                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6264                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6265                let mut buffer_end = buffer_start;
6266                buffer_end.add_assign(&buffer_range_len);
6267                let start = self.diff_transforms.start().0 .0;
6268                let end = self.diff_transforms.end(&()).0 .0;
6269                return Some(MultiBufferRegion {
6270                    buffer,
6271                    excerpt,
6272                    has_trailing_newline: *has_trailing_newline,
6273                    is_main_buffer: false,
6274                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6275                        hunk_info.hunk_secondary_status,
6276                    )),
6277                    buffer_range: buffer_start..buffer_end,
6278                    range: start..end,
6279                });
6280            }
6281            DiffTransform::BufferContent {
6282                inserted_hunk_info, ..
6283            } => {
6284                let buffer = &excerpt.buffer;
6285                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6286
6287                let mut start = self.diff_transforms.start().0 .0;
6288                let mut buffer_start = buffer_context_start;
6289                if self.diff_transforms.start().1 < *self.excerpts.start() {
6290                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1 .0;
6291                    start.add_assign(&overshoot);
6292                } else {
6293                    let overshoot = self.diff_transforms.start().1 .0 - self.excerpts.start().0;
6294                    buffer_start.add_assign(&overshoot);
6295                }
6296
6297                let mut end;
6298                let mut buffer_end;
6299                let has_trailing_newline;
6300                if self.diff_transforms.end(&()).1 .0 < self.excerpts.end(&()).0 {
6301                    let overshoot = self.diff_transforms.end(&()).1 .0 - self.excerpts.start().0;
6302                    end = self.diff_transforms.end(&()).0 .0;
6303                    buffer_end = buffer_context_start;
6304                    buffer_end.add_assign(&overshoot);
6305                    has_trailing_newline = false;
6306                } else {
6307                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1 .0;
6308                    end = self.diff_transforms.start().0 .0;
6309                    end.add_assign(&overshoot);
6310                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6311                    has_trailing_newline = excerpt.has_trailing_newline;
6312                };
6313
6314                Some(MultiBufferRegion {
6315                    buffer,
6316                    excerpt,
6317                    has_trailing_newline,
6318                    is_main_buffer: true,
6319                    diff_hunk_status: inserted_hunk_info
6320                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6321                    buffer_range: buffer_start..buffer_end,
6322                    range: start..end,
6323                })
6324            }
6325        }
6326    }
6327
6328    fn excerpt(&self) -> Option<&'a Excerpt> {
6329        self.excerpts.item()
6330    }
6331}
6332
6333impl History {
6334    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6335        self.transaction_depth += 1;
6336        if self.transaction_depth == 1 {
6337            let id = self.next_transaction_id.tick();
6338            self.undo_stack.push(Transaction {
6339                id,
6340                buffer_transactions: Default::default(),
6341                first_edit_at: now,
6342                last_edit_at: now,
6343                suppress_grouping: false,
6344            });
6345            Some(id)
6346        } else {
6347            None
6348        }
6349    }
6350
6351    fn end_transaction(
6352        &mut self,
6353        now: Instant,
6354        buffer_transactions: HashMap<BufferId, TransactionId>,
6355    ) -> bool {
6356        assert_ne!(self.transaction_depth, 0);
6357        self.transaction_depth -= 1;
6358        if self.transaction_depth == 0 {
6359            if buffer_transactions.is_empty() {
6360                self.undo_stack.pop();
6361                false
6362            } else {
6363                self.redo_stack.clear();
6364                let transaction = self.undo_stack.last_mut().unwrap();
6365                transaction.last_edit_at = now;
6366                for (buffer_id, transaction_id) in buffer_transactions {
6367                    transaction
6368                        .buffer_transactions
6369                        .entry(buffer_id)
6370                        .or_insert(transaction_id);
6371                }
6372                true
6373            }
6374        } else {
6375            false
6376        }
6377    }
6378
6379    fn push_transaction<'a, T>(
6380        &mut self,
6381        buffer_transactions: T,
6382        now: Instant,
6383        cx: &Context<MultiBuffer>,
6384    ) where
6385        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6386    {
6387        assert_eq!(self.transaction_depth, 0);
6388        let transaction = Transaction {
6389            id: self.next_transaction_id.tick(),
6390            buffer_transactions: buffer_transactions
6391                .into_iter()
6392                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6393                .collect(),
6394            first_edit_at: now,
6395            last_edit_at: now,
6396            suppress_grouping: false,
6397        };
6398        if !transaction.buffer_transactions.is_empty() {
6399            self.undo_stack.push(transaction);
6400            self.redo_stack.clear();
6401        }
6402    }
6403
6404    fn finalize_last_transaction(&mut self) {
6405        if let Some(transaction) = self.undo_stack.last_mut() {
6406            transaction.suppress_grouping = true;
6407        }
6408    }
6409
6410    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6411        if let Some(ix) = self
6412            .undo_stack
6413            .iter()
6414            .rposition(|transaction| transaction.id == transaction_id)
6415        {
6416            Some(self.undo_stack.remove(ix))
6417        } else if let Some(ix) = self
6418            .redo_stack
6419            .iter()
6420            .rposition(|transaction| transaction.id == transaction_id)
6421        {
6422            Some(self.redo_stack.remove(ix))
6423        } else {
6424            None
6425        }
6426    }
6427
6428    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6429        self.undo_stack
6430            .iter()
6431            .find(|transaction| transaction.id == transaction_id)
6432            .or_else(|| {
6433                self.redo_stack
6434                    .iter()
6435                    .find(|transaction| transaction.id == transaction_id)
6436            })
6437    }
6438
6439    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6440        self.undo_stack
6441            .iter_mut()
6442            .find(|transaction| transaction.id == transaction_id)
6443            .or_else(|| {
6444                self.redo_stack
6445                    .iter_mut()
6446                    .find(|transaction| transaction.id == transaction_id)
6447            })
6448    }
6449
6450    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6451        assert_eq!(self.transaction_depth, 0);
6452        if let Some(transaction) = self.undo_stack.pop() {
6453            self.redo_stack.push(transaction);
6454            self.redo_stack.last_mut()
6455        } else {
6456            None
6457        }
6458    }
6459
6460    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6461        assert_eq!(self.transaction_depth, 0);
6462        if let Some(transaction) = self.redo_stack.pop() {
6463            self.undo_stack.push(transaction);
6464            self.undo_stack.last_mut()
6465        } else {
6466            None
6467        }
6468    }
6469
6470    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6471        let ix = self
6472            .undo_stack
6473            .iter()
6474            .rposition(|transaction| transaction.id == transaction_id)?;
6475        let transaction = self.undo_stack.remove(ix);
6476        self.redo_stack.push(transaction);
6477        self.redo_stack.last()
6478    }
6479
6480    fn group(&mut self) -> Option<TransactionId> {
6481        let mut count = 0;
6482        let mut transactions = self.undo_stack.iter();
6483        if let Some(mut transaction) = transactions.next_back() {
6484            while let Some(prev_transaction) = transactions.next_back() {
6485                if !prev_transaction.suppress_grouping
6486                    && transaction.first_edit_at - prev_transaction.last_edit_at
6487                        <= self.group_interval
6488                {
6489                    transaction = prev_transaction;
6490                    count += 1;
6491                } else {
6492                    break;
6493                }
6494            }
6495        }
6496        self.group_trailing(count)
6497    }
6498
6499    fn group_until(&mut self, transaction_id: TransactionId) {
6500        let mut count = 0;
6501        for transaction in self.undo_stack.iter().rev() {
6502            if transaction.id == transaction_id {
6503                self.group_trailing(count);
6504                break;
6505            } else if transaction.suppress_grouping {
6506                break;
6507            } else {
6508                count += 1;
6509            }
6510        }
6511    }
6512
6513    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6514        let new_len = self.undo_stack.len() - n;
6515        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6516        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6517            if let Some(transaction) = transactions_to_merge.last() {
6518                last_transaction.last_edit_at = transaction.last_edit_at;
6519            }
6520            for to_merge in transactions_to_merge {
6521                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6522                    last_transaction
6523                        .buffer_transactions
6524                        .entry(*buffer_id)
6525                        .or_insert(*transaction_id);
6526                }
6527            }
6528        }
6529
6530        self.undo_stack.truncate(new_len);
6531        self.undo_stack.last().map(|t| t.id)
6532    }
6533}
6534
6535impl Excerpt {
6536    fn new(
6537        id: ExcerptId,
6538        locator: Locator,
6539        buffer_id: BufferId,
6540        buffer: BufferSnapshot,
6541        range: ExcerptRange<text::Anchor>,
6542        has_trailing_newline: bool,
6543    ) -> Self {
6544        Excerpt {
6545            id,
6546            locator,
6547            max_buffer_row: range.context.end.to_point(&buffer).row,
6548            text_summary: buffer
6549                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6550            buffer_id,
6551            buffer,
6552            range,
6553            has_trailing_newline,
6554        }
6555    }
6556
6557    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6558        let content_start = self.range.context.start.to_offset(&self.buffer);
6559        let chunks_start = content_start + range.start;
6560        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6561
6562        let footer_height = if self.has_trailing_newline
6563            && range.start <= self.text_summary.len
6564            && range.end > self.text_summary.len
6565        {
6566            1
6567        } else {
6568            0
6569        };
6570
6571        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6572
6573        ExcerptChunks {
6574            excerpt_id: self.id,
6575            content_chunks,
6576            footer_height,
6577        }
6578    }
6579
6580    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6581        let content_start = self.range.context.start.to_offset(&self.buffer);
6582        let chunks_start = content_start + range.start;
6583        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6584        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6585        excerpt_chunks.footer_height = if self.has_trailing_newline
6586            && range.start <= self.text_summary.len
6587            && range.end > self.text_summary.len
6588        {
6589            1
6590        } else {
6591            0
6592        };
6593    }
6594
6595    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6596        if text_anchor
6597            .cmp(&self.range.context.start, &self.buffer)
6598            .is_lt()
6599        {
6600            self.range.context.start
6601        } else if text_anchor
6602            .cmp(&self.range.context.end, &self.buffer)
6603            .is_gt()
6604        {
6605            self.range.context.end
6606        } else {
6607            text_anchor
6608        }
6609    }
6610
6611    fn contains(&self, anchor: &Anchor) -> bool {
6612        Some(self.buffer_id) == anchor.buffer_id
6613            && self
6614                .range
6615                .context
6616                .start
6617                .cmp(&anchor.text_anchor, &self.buffer)
6618                .is_le()
6619            && self
6620                .range
6621                .context
6622                .end
6623                .cmp(&anchor.text_anchor, &self.buffer)
6624                .is_ge()
6625    }
6626
6627    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6628    fn buffer_start_offset(&self) -> usize {
6629        self.range.context.start.to_offset(&self.buffer)
6630    }
6631
6632    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6633    fn buffer_end_offset(&self) -> usize {
6634        self.buffer_start_offset() + self.text_summary.len
6635    }
6636}
6637
6638impl<'a> MultiBufferExcerpt<'a> {
6639    pub fn id(&self) -> ExcerptId {
6640        self.excerpt.id
6641    }
6642
6643    pub fn buffer_id(&self) -> BufferId {
6644        self.excerpt.buffer_id
6645    }
6646
6647    pub fn start_anchor(&self) -> Anchor {
6648        Anchor {
6649            buffer_id: Some(self.excerpt.buffer_id),
6650            excerpt_id: self.excerpt.id,
6651            text_anchor: self.excerpt.range.context.start,
6652            diff_base_anchor: None,
6653        }
6654    }
6655
6656    pub fn end_anchor(&self) -> Anchor {
6657        Anchor {
6658            buffer_id: Some(self.excerpt.buffer_id),
6659            excerpt_id: self.excerpt.id,
6660            text_anchor: self.excerpt.range.context.end,
6661            diff_base_anchor: None,
6662        }
6663    }
6664
6665    pub fn buffer(&self) -> &'a BufferSnapshot {
6666        &self.excerpt.buffer
6667    }
6668
6669    pub fn buffer_range(&self) -> Range<usize> {
6670        self.buffer_offset
6671            ..self
6672                .excerpt
6673                .range
6674                .context
6675                .end
6676                .to_offset(&self.excerpt.buffer.text)
6677    }
6678
6679    pub fn start_offset(&self) -> usize {
6680        self.offset
6681    }
6682
6683    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6684    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6685        self.map_range_to_buffer(offset..offset).start
6686    }
6687
6688    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6689    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6690        self.diff_transforms
6691            .seek(&OutputDimension(range.start), Bias::Right, &());
6692        let start = self.map_offset_to_buffer_internal(range.start);
6693        let end = if range.end > range.start {
6694            self.diff_transforms
6695                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6696            self.map_offset_to_buffer_internal(range.end)
6697        } else {
6698            start
6699        };
6700        start..end
6701    }
6702
6703    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6704        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6705        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6706            excerpt_offset.0 += offset - self.diff_transforms.start().0 .0;
6707        };
6708        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6709        self.buffer_offset + offset_in_excerpt
6710    }
6711
6712    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6713    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6714        self.map_range_from_buffer(buffer_offset..buffer_offset)
6715            .start
6716    }
6717
6718    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6719    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6720        if buffer_range.start < self.buffer_offset {
6721            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6722            return buffer_range;
6723        }
6724        let overshoot = buffer_range.start - self.buffer_offset;
6725        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6726        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6727        if excerpt_offset.0 < self.diff_transforms.start().1 .0 {
6728            log::warn!("Attempting to map a range from a buffer offset that starts before the current buffer offset");
6729            return buffer_range;
6730        }
6731        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6732        let start = self.diff_transforms.start().0 .0 + overshoot;
6733
6734        let end = if buffer_range.end > buffer_range.start {
6735            let overshoot = buffer_range.end - self.buffer_offset;
6736            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6737            self.diff_transforms
6738                .seek_forward(&excerpt_offset, Bias::Right, &());
6739            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1 .0;
6740            self.diff_transforms.start().0 .0 + overshoot
6741        } else {
6742            start
6743        };
6744
6745        start..end
6746    }
6747
6748    /// Returns true if the entirety of the given range is in the buffer's excerpt
6749    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6750        range.start >= self.excerpt.buffer_start_offset()
6751            && range.end <= self.excerpt.buffer_end_offset()
6752    }
6753
6754    pub fn max_buffer_row(&self) -> u32 {
6755        self.excerpt.max_buffer_row
6756    }
6757}
6758
6759impl ExcerptId {
6760    pub fn min() -> Self {
6761        Self(0)
6762    }
6763
6764    pub fn max() -> Self {
6765        Self(usize::MAX)
6766    }
6767
6768    pub fn to_proto(&self) -> u64 {
6769        self.0 as _
6770    }
6771
6772    pub fn from_proto(proto: u64) -> Self {
6773        Self(proto as _)
6774    }
6775
6776    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6777        let a = snapshot.excerpt_locator_for_id(*self);
6778        let b = snapshot.excerpt_locator_for_id(*other);
6779        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6780    }
6781}
6782
6783impl From<ExcerptId> for usize {
6784    fn from(val: ExcerptId) -> Self {
6785        val.0
6786    }
6787}
6788
6789impl fmt::Debug for Excerpt {
6790    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6791        f.debug_struct("Excerpt")
6792            .field("id", &self.id)
6793            .field("locator", &self.locator)
6794            .field("buffer_id", &self.buffer_id)
6795            .field("range", &self.range)
6796            .field("text_summary", &self.text_summary)
6797            .field("has_trailing_newline", &self.has_trailing_newline)
6798            .finish()
6799    }
6800}
6801
6802impl sum_tree::Item for Excerpt {
6803    type Summary = ExcerptSummary;
6804
6805    fn summary(&self, _cx: &()) -> Self::Summary {
6806        let mut text = self.text_summary;
6807        if self.has_trailing_newline {
6808            text += TextSummary::from("\n");
6809        }
6810        ExcerptSummary {
6811            excerpt_id: self.id,
6812            excerpt_locator: self.locator.clone(),
6813            widest_line_number: self.max_buffer_row,
6814            text,
6815        }
6816    }
6817}
6818
6819impl sum_tree::Item for ExcerptIdMapping {
6820    type Summary = ExcerptId;
6821
6822    fn summary(&self, _cx: &()) -> Self::Summary {
6823        self.id
6824    }
6825}
6826
6827impl sum_tree::KeyedItem for ExcerptIdMapping {
6828    type Key = ExcerptId;
6829
6830    fn key(&self) -> Self::Key {
6831        self.id
6832    }
6833}
6834
6835impl DiffTransform {
6836    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6837        match self {
6838            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6839            DiffTransform::BufferContent {
6840                inserted_hunk_info, ..
6841            } => *inserted_hunk_info,
6842        }
6843    }
6844}
6845
6846impl sum_tree::Item for DiffTransform {
6847    type Summary = DiffTransformSummary;
6848
6849    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
6850        match self {
6851            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6852                input: *summary,
6853                output: *summary,
6854            },
6855            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6856                input: TextSummary::default(),
6857                output: *summary,
6858            },
6859        }
6860    }
6861}
6862
6863impl DiffTransformSummary {
6864    fn excerpt_len(&self) -> ExcerptOffset {
6865        ExcerptOffset::new(self.input.len)
6866    }
6867}
6868
6869impl sum_tree::Summary for DiffTransformSummary {
6870    type Context = ();
6871
6872    fn zero(_: &Self::Context) -> Self {
6873        DiffTransformSummary {
6874            input: TextSummary::default(),
6875            output: TextSummary::default(),
6876        }
6877    }
6878
6879    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
6880        self.input += &summary.input;
6881        self.output += &summary.output;
6882    }
6883}
6884
6885impl sum_tree::Summary for ExcerptId {
6886    type Context = ();
6887
6888    fn zero(_cx: &()) -> Self {
6889        Default::default()
6890    }
6891
6892    fn add_summary(&mut self, other: &Self, _: &()) {
6893        *self = *other;
6894    }
6895}
6896
6897impl sum_tree::Summary for ExcerptSummary {
6898    type Context = ();
6899
6900    fn zero(_cx: &()) -> Self {
6901        Default::default()
6902    }
6903
6904    fn add_summary(&mut self, summary: &Self, _: &()) {
6905        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6906        self.excerpt_locator = summary.excerpt_locator.clone();
6907        self.text.add_summary(&summary.text, &());
6908        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6909    }
6910}
6911
6912impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6913    fn zero(_cx: &()) -> Self {
6914        Default::default()
6915    }
6916
6917    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6918        self.value += summary.text.len;
6919    }
6920}
6921
6922impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6923    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6924        Ord::cmp(&self.value, &cursor_location.text.len)
6925    }
6926}
6927
6928impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6929    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
6930        Ord::cmp(&Some(self), cursor_location)
6931    }
6932}
6933
6934impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6935    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
6936        Ord::cmp(self, &cursor_location.excerpt_locator)
6937    }
6938}
6939
6940impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6941    fn zero(_cx: &()) -> Self {
6942        Default::default()
6943    }
6944
6945    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6946        self.value += summary.text.lines;
6947    }
6948}
6949
6950impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6951    for ExcerptDimension<D>
6952{
6953    fn zero(_: &()) -> Self {
6954        ExcerptDimension(D::default())
6955    }
6956
6957    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6958        self.0.add_assign(&D::from_text_summary(&summary.text))
6959    }
6960}
6961
6962impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6963    fn zero(_cx: &()) -> Self {
6964        Default::default()
6965    }
6966
6967    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6968        *self = Some(&summary.excerpt_locator);
6969    }
6970}
6971
6972impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6973    fn zero(_cx: &()) -> Self {
6974        Default::default()
6975    }
6976
6977    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
6978        *self = Some(summary.excerpt_id);
6979    }
6980}
6981
6982#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6983struct ExcerptDimension<T>(T);
6984
6985#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6986struct OutputDimension<T>(T);
6987
6988impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6989    fn zero(_: &()) -> Self {
6990        ExcerptOffset::new(0)
6991    }
6992
6993    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
6994        self.value += summary.input.len;
6995    }
6996}
6997
6998impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6999    fn zero(_: &()) -> Self {
7000        ExcerptPoint::new(0, 0)
7001    }
7002
7003    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7004        self.value += summary.input.lines;
7005    }
7006}
7007
7008impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7009    for ExcerptDimension<D>
7010{
7011    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7012        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7013    }
7014}
7015
7016impl<D: TextDimension + Ord>
7017    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7018    for ExcerptDimension<D>
7019{
7020    fn cmp(
7021        &self,
7022        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7023        _: &(),
7024    ) -> cmp::Ordering {
7025        Ord::cmp(&self.0, &cursor_location.1 .0)
7026    }
7027}
7028
7029impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7030    fn zero(_: &()) -> Self {
7031        ExcerptDimension(D::default())
7032    }
7033
7034    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7035        self.0.add_assign(&D::from_text_summary(&summary.input))
7036    }
7037}
7038
7039impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7040    fn zero(_: &()) -> Self {
7041        OutputDimension(D::default())
7042    }
7043
7044    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7045        self.0.add_assign(&D::from_text_summary(&summary.output))
7046    }
7047}
7048
7049impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7050    fn zero(_: &()) -> Self {
7051        TextSummary::default()
7052    }
7053
7054    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7055        *self += summary.output
7056    }
7057}
7058
7059impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7060    fn zero(_: &()) -> Self {
7061        0
7062    }
7063
7064    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7065        *self += summary.output.len
7066    }
7067}
7068
7069impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7070    fn zero(_: &()) -> Self {
7071        Point::new(0, 0)
7072    }
7073
7074    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7075        *self += summary.output.lines
7076    }
7077}
7078
7079impl MultiBufferRows<'_> {
7080    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7081        self.point = Point::new(row, 0);
7082        self.cursor.seek(&self.point);
7083    }
7084}
7085
7086impl Iterator for MultiBufferRows<'_> {
7087    type Item = RowInfo;
7088
7089    fn next(&mut self) -> Option<Self::Item> {
7090        if self.is_empty && self.point.row == 0 {
7091            self.point += Point::new(1, 0);
7092            return Some(RowInfo {
7093                buffer_id: None,
7094                buffer_row: Some(0),
7095                multibuffer_row: Some(MultiBufferRow(0)),
7096                diff_status: None,
7097            });
7098        }
7099
7100        let mut region = self.cursor.region()?;
7101        while self.point >= region.range.end {
7102            self.cursor.next();
7103            if let Some(next_region) = self.cursor.region() {
7104                region = next_region;
7105            } else {
7106                if self.point == self.cursor.diff_transforms.end(&()).0 .0 {
7107                    let multibuffer_row = MultiBufferRow(self.point.row);
7108                    self.point += Point::new(1, 0);
7109                    let last_excerpt = self
7110                        .cursor
7111                        .excerpts
7112                        .item()
7113                        .or(self.cursor.excerpts.prev_item())?;
7114                    let last_row = last_excerpt
7115                        .range
7116                        .context
7117                        .end
7118                        .to_point(&last_excerpt.buffer)
7119                        .row;
7120                    return Some(RowInfo {
7121                        buffer_id: Some(last_excerpt.buffer_id),
7122                        buffer_row: Some(last_row),
7123                        multibuffer_row: Some(multibuffer_row),
7124                        diff_status: None,
7125                    });
7126                } else {
7127                    return None;
7128                }
7129            };
7130        }
7131
7132        let overshoot = self.point - region.range.start;
7133        let buffer_point = region.buffer_range.start + overshoot;
7134        let result = Some(RowInfo {
7135            buffer_id: Some(region.buffer.remote_id()),
7136            buffer_row: Some(buffer_point.row),
7137            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7138            diff_status: region
7139                .diff_hunk_status
7140                .filter(|_| self.point < region.range.end),
7141        });
7142        self.point += Point::new(1, 0);
7143        result
7144    }
7145}
7146
7147impl<'a> MultiBufferChunks<'a> {
7148    pub fn offset(&self) -> usize {
7149        self.range.start
7150    }
7151
7152    pub fn seek(&mut self, range: Range<usize>) {
7153        self.diff_transforms.seek(&range.end, Bias::Right, &());
7154        let mut excerpt_end = self.diff_transforms.start().1;
7155        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7156            let overshoot = range.end - self.diff_transforms.start().0;
7157            excerpt_end.value += overshoot;
7158        }
7159
7160        self.diff_transforms.seek(&range.start, Bias::Right, &());
7161        let mut excerpt_start = self.diff_transforms.start().1;
7162        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7163            let overshoot = range.start - self.diff_transforms.start().0;
7164            excerpt_start.value += overshoot;
7165        }
7166
7167        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7168        self.buffer_chunk.take();
7169        self.range = range;
7170    }
7171
7172    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7173        self.excerpt_offset_range = new_range.clone();
7174        self.excerpts.seek(&new_range.start, Bias::Right, &());
7175        if let Some(excerpt) = self.excerpts.item() {
7176            let excerpt_start = *self.excerpts.start();
7177            if let Some(excerpt_chunks) = self
7178                .excerpt_chunks
7179                .as_mut()
7180                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7181            {
7182                excerpt.seek_chunks(
7183                    excerpt_chunks,
7184                    (self.excerpt_offset_range.start - excerpt_start).value
7185                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7186                );
7187            } else {
7188                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7189                    (self.excerpt_offset_range.start - excerpt_start).value
7190                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7191                    self.language_aware,
7192                ));
7193            }
7194        } else {
7195            self.excerpt_chunks = None;
7196        }
7197    }
7198
7199    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7200        loop {
7201            if self.excerpt_offset_range.is_empty() {
7202                return None;
7203            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7204                self.excerpt_offset_range.start.value += chunk.text.len();
7205                return Some(chunk);
7206            } else {
7207                self.excerpts.next(&());
7208                let excerpt = self.excerpts.item()?;
7209                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7210                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7211                    self.language_aware,
7212                ));
7213            }
7214        }
7215    }
7216}
7217
7218impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7219    type Item = &'a str;
7220
7221    fn next(&mut self) -> Option<Self::Item> {
7222        let mut region = self.cursor.region()?;
7223        if self.offset == region.range.start {
7224            self.cursor.prev();
7225            region = self.cursor.region()?;
7226            let start_overshoot = self.start.saturating_sub(region.range.start);
7227            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7228                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7229            ));
7230        }
7231
7232        if self.offset == region.range.end && region.has_trailing_newline {
7233            self.offset -= 1;
7234            Some("\n")
7235        } else {
7236            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7237            self.offset -= chunk.len();
7238            Some(chunk)
7239        }
7240    }
7241}
7242
7243impl<'a> Iterator for MultiBufferChunks<'a> {
7244    type Item = Chunk<'a>;
7245
7246    fn next(&mut self) -> Option<Chunk<'a>> {
7247        if self.range.start >= self.range.end {
7248            return None;
7249        }
7250        if self.range.start == self.diff_transforms.end(&()).0 {
7251            self.diff_transforms.next(&());
7252        }
7253
7254        let diff_transform_start = self.diff_transforms.start().0;
7255        let diff_transform_end = self.diff_transforms.end(&()).0;
7256        debug_assert!(self.range.start < diff_transform_end);
7257
7258        let diff_transform = self.diff_transforms.item()?;
7259        match diff_transform {
7260            DiffTransform::BufferContent { .. } => {
7261                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7262                    chunk
7263                } else {
7264                    let chunk = self.next_excerpt_chunk().unwrap();
7265                    self.buffer_chunk.insert(chunk)
7266                };
7267
7268                let chunk_end = self.range.start + chunk.text.len();
7269                let diff_transform_end = diff_transform_end.min(self.range.end);
7270
7271                if diff_transform_end < chunk_end {
7272                    let (before, after) =
7273                        chunk.text.split_at(diff_transform_end - self.range.start);
7274                    self.range.start = diff_transform_end;
7275                    chunk.text = after;
7276                    Some(Chunk {
7277                        text: before,
7278                        ..chunk.clone()
7279                    })
7280                } else {
7281                    self.range.start = chunk_end;
7282                    self.buffer_chunk.take()
7283                }
7284            }
7285            DiffTransform::DeletedHunk {
7286                buffer_id,
7287                base_text_byte_range,
7288                has_trailing_newline,
7289                ..
7290            } => {
7291                let base_text_start =
7292                    base_text_byte_range.start + self.range.start - diff_transform_start;
7293                let base_text_end =
7294                    base_text_byte_range.start + self.range.end - diff_transform_start;
7295                let base_text_end = base_text_end.min(base_text_byte_range.end);
7296
7297                let mut chunks = if let Some((_, mut chunks)) = self
7298                    .diff_base_chunks
7299                    .take()
7300                    .filter(|(id, _)| id == buffer_id)
7301                {
7302                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7303                    {
7304                        chunks.seek(base_text_start..base_text_end);
7305                    }
7306                    chunks
7307                } else {
7308                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7309                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7310                };
7311
7312                let chunk = if let Some(chunk) = chunks.next() {
7313                    self.range.start += chunk.text.len();
7314                    self.diff_base_chunks = Some((*buffer_id, chunks));
7315                    chunk
7316                } else {
7317                    debug_assert!(has_trailing_newline);
7318                    self.range.start += "\n".len();
7319                    Chunk {
7320                        text: "\n",
7321                        ..Default::default()
7322                    }
7323                };
7324                Some(chunk)
7325            }
7326        }
7327    }
7328}
7329
7330impl MultiBufferBytes<'_> {
7331    fn consume(&mut self, len: usize) {
7332        self.range.start += len;
7333        self.chunk = &self.chunk[len..];
7334
7335        if !self.range.is_empty() && self.chunk.is_empty() {
7336            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7337                self.chunk = chunk;
7338            } else if self.has_trailing_newline {
7339                self.has_trailing_newline = false;
7340                self.chunk = b"\n";
7341            } else {
7342                self.cursor.next();
7343                if let Some(region) = self.cursor.region() {
7344                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7345                        region.buffer_range.start
7346                            ..(region.buffer_range.start + self.range.end - region.range.start)
7347                                .min(region.buffer_range.end),
7348                    );
7349                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7350                    self.excerpt_bytes = Some(excerpt_bytes);
7351                    self.has_trailing_newline =
7352                        region.has_trailing_newline && self.range.end >= region.range.end;
7353                    if self.chunk.is_empty() && self.has_trailing_newline {
7354                        self.has_trailing_newline = false;
7355                        self.chunk = b"\n";
7356                    }
7357                }
7358            }
7359        }
7360    }
7361}
7362
7363impl<'a> Iterator for MultiBufferBytes<'a> {
7364    type Item = &'a [u8];
7365
7366    fn next(&mut self) -> Option<Self::Item> {
7367        let chunk = self.chunk;
7368        if chunk.is_empty() {
7369            None
7370        } else {
7371            self.consume(chunk.len());
7372            Some(chunk)
7373        }
7374    }
7375}
7376
7377impl io::Read for MultiBufferBytes<'_> {
7378    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7379        let len = cmp::min(buf.len(), self.chunk.len());
7380        buf[..len].copy_from_slice(&self.chunk[..len]);
7381        if len > 0 {
7382            self.consume(len);
7383        }
7384        Ok(len)
7385    }
7386}
7387
7388impl io::Read for ReversedMultiBufferBytes<'_> {
7389    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7390        let len = cmp::min(buf.len(), self.chunk.len());
7391        buf[..len].copy_from_slice(&self.chunk[..len]);
7392        buf[..len].reverse();
7393        if len > 0 {
7394            self.range.end -= len;
7395            self.chunk = &self.chunk[..self.chunk.len() - len];
7396            if !self.range.is_empty() && self.chunk.is_empty() {
7397                if let Some(chunk) = self.chunks.next() {
7398                    self.chunk = chunk.as_bytes();
7399                }
7400            }
7401        }
7402        Ok(len)
7403    }
7404}
7405
7406impl<'a> Iterator for ExcerptChunks<'a> {
7407    type Item = Chunk<'a>;
7408
7409    fn next(&mut self) -> Option<Self::Item> {
7410        if let Some(chunk) = self.content_chunks.next() {
7411            return Some(chunk);
7412        }
7413
7414        if self.footer_height > 0 {
7415            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7416            self.footer_height = 0;
7417            return Some(Chunk {
7418                text,
7419                ..Default::default()
7420            });
7421        }
7422
7423        None
7424    }
7425}
7426
7427impl ToOffset for Point {
7428    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7429        snapshot.point_to_offset(*self)
7430    }
7431}
7432
7433impl ToOffset for usize {
7434    #[track_caller]
7435    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7436        assert!(*self <= snapshot.len(), "offset is out of range");
7437        *self
7438    }
7439}
7440
7441impl ToOffset for OffsetUtf16 {
7442    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7443        snapshot.offset_utf16_to_offset(*self)
7444    }
7445}
7446
7447impl ToOffset for PointUtf16 {
7448    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7449        snapshot.point_utf16_to_offset(*self)
7450    }
7451}
7452
7453impl ToOffsetUtf16 for OffsetUtf16 {
7454    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7455        *self
7456    }
7457}
7458
7459impl ToOffsetUtf16 for usize {
7460    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7461        snapshot.offset_to_offset_utf16(*self)
7462    }
7463}
7464
7465impl ToPoint for usize {
7466    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7467        snapshot.offset_to_point(*self)
7468    }
7469}
7470
7471impl ToPoint for Point {
7472    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7473        *self
7474    }
7475}
7476
7477impl ToPointUtf16 for usize {
7478    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7479        snapshot.offset_to_point_utf16(*self)
7480    }
7481}
7482
7483impl ToPointUtf16 for Point {
7484    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7485        snapshot.point_to_point_utf16(*self)
7486    }
7487}
7488
7489impl ToPointUtf16 for PointUtf16 {
7490    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7491        *self
7492    }
7493}
7494
7495impl From<ExcerptId> for EntityId {
7496    fn from(id: ExcerptId) -> Self {
7497        EntityId::from(id.0 as u64)
7498    }
7499}
7500
7501pub fn build_excerpt_ranges<T>(
7502    buffer: &BufferSnapshot,
7503    ranges: &[Range<T>],
7504    context_line_count: u32,
7505) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7506where
7507    T: text::ToPoint,
7508{
7509    let max_point = buffer.max_point();
7510    let mut range_counts = Vec::new();
7511    let mut excerpt_ranges = Vec::new();
7512    let mut range_iter = ranges
7513        .iter()
7514        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7515        .peekable();
7516    while let Some(range) = range_iter.next() {
7517        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7518        let row = (range.end.row + context_line_count).min(max_point.row);
7519        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7520
7521        let mut ranges_in_excerpt = 1;
7522
7523        while let Some(next_range) = range_iter.peek() {
7524            if next_range.start.row <= excerpt_end.row + context_line_count {
7525                let row = (next_range.end.row + context_line_count).min(max_point.row);
7526                excerpt_end = Point::new(row, buffer.line_len(row));
7527
7528                ranges_in_excerpt += 1;
7529                range_iter.next();
7530            } else {
7531                break;
7532            }
7533        }
7534
7535        excerpt_ranges.push(ExcerptRange {
7536            context: excerpt_start..excerpt_end,
7537            primary: Some(range),
7538        });
7539        range_counts.push(ranges_in_excerpt);
7540    }
7541
7542    (excerpt_ranges, range_counts)
7543}