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