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