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