1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod position;
   6mod transaction;
   7
   8use self::transaction::History;
   9
  10pub use anchor::{Anchor, AnchorRangeExt, Offset};
  11pub use position::{TypedOffset, TypedPoint, TypedRow};
  12
  13use anyhow::{Result, anyhow};
  14use buffer_diff::{
  15    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  16    DiffHunkStatusKind,
  17};
  18use clock::ReplicaId;
  19use collections::{BTreeMap, Bound, HashMap, HashSet};
  20use gpui::{App, Context, Entity, EntityId, EventEmitter};
  21use itertools::Itertools;
  22use language::{
  23    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  24    CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, DiskState, File,
  25    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  26    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  27    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  28    language_settings::{LanguageSettings, language_settings},
  29};
  30
  31#[cfg(any(test, feature = "test-support"))]
  32use gpui::AppContext as _;
  33
  34use rope::DimensionPair;
  35use smallvec::SmallVec;
  36use smol::future::yield_now;
  37use std::{
  38    any::type_name,
  39    borrow::Cow,
  40    cell::{Cell, Ref, RefCell},
  41    cmp, fmt,
  42    future::Future,
  43    io,
  44    iter::{self, FromIterator},
  45    mem,
  46    ops::{Range, RangeBounds, Sub},
  47    rc::Rc,
  48    str,
  49    sync::Arc,
  50    time::Duration,
  51};
  52use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, Summary, TreeMap};
  53use text::{
  54    BufferId, Edit, LineIndent, TextSummary,
  55    locator::Locator,
  56    subscription::{Subscription, Topic},
  57};
  58use theme::SyntaxTheme;
  59use util::post_inc;
  60
  61pub use self::path_key::PathKey;
  62
  63#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  64pub struct ExcerptId(u32);
  65
  66/// One or more [`Buffers`](Buffer) being edited in a single view.
  67///
  68/// See <https://zed.dev/features#multi-buffers>
  69pub struct MultiBuffer {
  70    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  71    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  72    snapshot: RefCell<MultiBufferSnapshot>,
  73    /// Contains the state of the buffers being edited
  74    buffers: HashMap<BufferId, BufferState>,
  75    /// Mapping from path keys to their excerpts.
  76    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  77    /// Mapping from excerpt IDs to their path key.
  78    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  79    /// Mapping from buffer IDs to their diff states
  80    diffs: HashMap<BufferId, DiffState>,
  81    subscriptions: Topic,
  82    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  83    singleton: bool,
  84    /// The history of the multi-buffer.
  85    history: History,
  86    /// The explicit title of the multi-buffer.
  87    /// If `None`, it will be derived from the underlying path or content.
  88    title: Option<String>,
  89    /// The writing capability of the multi-buffer.
  90    capability: Capability,
  91    buffer_changed_since_sync: Rc<Cell<bool>>,
  92}
  93
  94#[derive(Clone, Debug, PartialEq, Eq)]
  95pub enum Event {
  96    ExcerptsAdded {
  97        buffer: Entity<Buffer>,
  98        predecessor: ExcerptId,
  99        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 100    },
 101    ExcerptsRemoved {
 102        ids: Vec<ExcerptId>,
 103        removed_buffer_ids: Vec<BufferId>,
 104    },
 105    ExcerptsExpanded {
 106        ids: Vec<ExcerptId>,
 107    },
 108    ExcerptsEdited {
 109        excerpt_ids: Vec<ExcerptId>,
 110        buffer_ids: Vec<BufferId>,
 111    },
 112    DiffHunksToggled,
 113    Edited {
 114        edited_buffer: Option<Entity<Buffer>>,
 115    },
 116    TransactionUndone {
 117        transaction_id: TransactionId,
 118    },
 119    Reloaded,
 120    LanguageChanged(BufferId),
 121    Reparsed(BufferId),
 122    Saved,
 123    FileHandleChanged,
 124    DirtyChanged,
 125    DiagnosticsUpdated,
 126    BufferDiffChanged,
 127}
 128
 129/// A diff hunk, representing a range of consequent lines in a multibuffer.
 130#[derive(Debug, Clone, PartialEq, Eq)]
 131pub struct MultiBufferDiffHunk {
 132    /// The row range in the multibuffer where this diff hunk appears.
 133    pub row_range: Range<MultiBufferRow>,
 134    /// The buffer ID that this hunk belongs to.
 135    pub buffer_id: BufferId,
 136    /// The range of the underlying buffer that this hunk corresponds to.
 137    pub buffer_range: Range<text::Anchor>,
 138    /// The excerpt that contains the diff hunk.
 139    pub excerpt_id: ExcerptId,
 140    /// The range within the buffer's diff base that this hunk corresponds to.
 141    pub diff_base_byte_range: Range<usize>,
 142    /// Whether or not this hunk also appears in the 'secondary diff'.
 143    pub secondary_status: DiffHunkSecondaryStatus,
 144}
 145
 146impl MultiBufferDiffHunk {
 147    pub fn status(&self) -> DiffHunkStatus {
 148        let kind = if self.buffer_range.start == self.buffer_range.end {
 149            DiffHunkStatusKind::Deleted
 150        } else if self.diff_base_byte_range.is_empty() {
 151            DiffHunkStatusKind::Added
 152        } else {
 153            DiffHunkStatusKind::Modified
 154        };
 155        DiffHunkStatus {
 156            kind,
 157            secondary: self.secondary_status,
 158        }
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (0..0)
 163            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 164    }
 165
 166    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 167        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 168        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 169        start..end
 170    }
 171}
 172
 173pub type MultiBufferPoint = Point;
 174type ExcerptOffset = TypedOffset<Excerpt>;
 175type ExcerptPoint = TypedPoint<Excerpt>;
 176
 177#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 178#[serde(transparent)]
 179pub struct MultiBufferRow(pub u32);
 180
 181impl MultiBufferRow {
 182    pub const MIN: Self = Self(0);
 183    pub const MAX: Self = Self(u32::MAX);
 184}
 185
 186impl std::ops::Add<usize> for MultiBufferRow {
 187    type Output = Self;
 188
 189    fn add(self, rhs: usize) -> Self::Output {
 190        MultiBufferRow(self.0 + rhs as u32)
 191    }
 192}
 193
 194pub trait ToOffset: 'static + fmt::Debug {
 195    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 196    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 197}
 198
 199pub trait ToPoint: 'static + fmt::Debug {
 200    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 201    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 202}
 203
 204struct BufferState {
 205    buffer: Entity<Buffer>,
 206    last_version: RefCell<clock::Global>,
 207    last_non_text_state_update_count: Cell<usize>,
 208    excerpts: Vec<Locator>,
 209    _subscriptions: [gpui::Subscription; 2],
 210}
 211
 212struct DiffState {
 213    diff: Entity<BufferDiff>,
 214    _subscription: gpui::Subscription,
 215}
 216
 217impl DiffState {
 218    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 219        DiffState {
 220            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 221                BufferDiffEvent::DiffChanged { changed_range } => {
 222                    if let Some(changed_range) = changed_range.clone() {
 223                        this.buffer_diff_changed(diff, changed_range, cx)
 224                    }
 225                    cx.emit(Event::BufferDiffChanged);
 226                }
 227                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 228                _ => {}
 229            }),
 230            diff,
 231        }
 232    }
 233}
 234
 235/// The contents of a [`MultiBuffer`] at a single point in time.
 236#[derive(Clone, Default)]
 237pub struct MultiBufferSnapshot {
 238    excerpts: SumTree<Excerpt>,
 239    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 240    diff_transforms: SumTree<DiffTransform>,
 241    non_text_state_update_count: usize,
 242    edit_count: usize,
 243    is_dirty: bool,
 244    has_deleted_file: bool,
 245    has_conflict: bool,
 246    /// immutable fields
 247    singleton: bool,
 248    excerpt_ids: SumTree<ExcerptIdMapping>,
 249    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 250    trailing_excerpt_update_count: usize,
 251    all_diff_hunks_expanded: bool,
 252    show_headers: bool,
 253}
 254
 255#[derive(Debug, Clone)]
 256enum DiffTransform {
 257    BufferContent {
 258        summary: TextSummary,
 259        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 260    },
 261    DeletedHunk {
 262        summary: TextSummary,
 263        buffer_id: BufferId,
 264        hunk_info: DiffTransformHunkInfo,
 265        base_text_byte_range: Range<usize>,
 266        has_trailing_newline: bool,
 267    },
 268}
 269
 270#[derive(Clone, Copy, Debug)]
 271struct DiffTransformHunkInfo {
 272    excerpt_id: ExcerptId,
 273    hunk_start_anchor: text::Anchor,
 274    hunk_secondary_status: DiffHunkSecondaryStatus,
 275}
 276
 277impl Eq for DiffTransformHunkInfo {}
 278
 279impl PartialEq for DiffTransformHunkInfo {
 280    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 281        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 282    }
 283}
 284
 285impl std::hash::Hash for DiffTransformHunkInfo {
 286    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 287        self.excerpt_id.hash(state);
 288        self.hunk_start_anchor.hash(state);
 289    }
 290}
 291
 292#[derive(Clone)]
 293pub struct ExcerptInfo {
 294    pub id: ExcerptId,
 295    pub buffer: BufferSnapshot,
 296    pub buffer_id: BufferId,
 297    pub range: ExcerptRange<text::Anchor>,
 298    pub end_row: MultiBufferRow,
 299}
 300
 301impl std::fmt::Debug for ExcerptInfo {
 302    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 303        f.debug_struct(type_name::<Self>())
 304            .field("id", &self.id)
 305            .field("buffer_id", &self.buffer_id)
 306            .field("path", &self.buffer.file().map(|f| f.path()))
 307            .field("range", &self.range)
 308            .finish()
 309    }
 310}
 311
 312/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 313#[derive(Debug)]
 314pub struct ExcerptBoundary {
 315    pub prev: Option<ExcerptInfo>,
 316    pub next: ExcerptInfo,
 317    /// The row in the `MultiBuffer` where the boundary is located
 318    pub row: MultiBufferRow,
 319}
 320
 321impl ExcerptBoundary {
 322    pub fn starts_new_buffer(&self) -> bool {
 323        match (self.prev.as_ref(), &self.next) {
 324            (None, _) => true,
 325            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 326        }
 327    }
 328}
 329
 330#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 331pub struct ExpandInfo {
 332    pub direction: ExpandExcerptDirection,
 333    pub excerpt_id: ExcerptId,
 334}
 335
 336#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 337pub struct RowInfo {
 338    pub buffer_id: Option<BufferId>,
 339    pub buffer_row: Option<u32>,
 340    pub multibuffer_row: Option<MultiBufferRow>,
 341    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 342    pub expand_info: Option<ExpandInfo>,
 343}
 344
 345/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 346#[derive(Clone)]
 347struct Excerpt {
 348    /// The unique identifier for this excerpt
 349    id: ExcerptId,
 350    /// The location of the excerpt in the [`MultiBuffer`]
 351    locator: Locator,
 352    /// The buffer being excerpted
 353    buffer_id: BufferId,
 354    /// A snapshot of the buffer being excerpted
 355    buffer: BufferSnapshot,
 356    /// The range of the buffer to be shown in the excerpt
 357    range: ExcerptRange<text::Anchor>,
 358    /// The last row in the excerpted slice of the buffer
 359    max_buffer_row: BufferRow,
 360    /// A summary of the text in the excerpt
 361    text_summary: TextSummary,
 362    has_trailing_newline: bool,
 363}
 364
 365/// A public view into an `Excerpt` in a [`MultiBuffer`].
 366///
 367/// Contains methods for getting the [`Buffer`] of the excerpt,
 368/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 369#[derive(Clone)]
 370pub struct MultiBufferExcerpt<'a> {
 371    excerpt: &'a Excerpt,
 372    diff_transforms: sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<usize>>,
 373    offset: usize,
 374    excerpt_offset: ExcerptDimension<usize>,
 375    buffer_offset: usize,
 376}
 377
 378#[derive(Clone, Debug)]
 379struct ExcerptIdMapping {
 380    id: ExcerptId,
 381    locator: Locator,
 382}
 383
 384/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 385/// These ranges are relative to the buffer itself
 386#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 387pub struct ExcerptRange<T> {
 388    /// The full range of text to be shown in the excerpt.
 389    pub context: Range<T>,
 390    /// The primary range of text to be highlighted in the excerpt.
 391    /// In a multi-buffer search, this would be the text that matched the search
 392    pub primary: Range<T>,
 393}
 394
 395impl<T: Clone> ExcerptRange<T> {
 396    pub fn new(context: Range<T>) -> Self {
 397        Self {
 398            context: context.clone(),
 399            primary: context,
 400        }
 401    }
 402}
 403
 404#[derive(Clone, Debug, Default)]
 405pub struct ExcerptSummary {
 406    excerpt_id: ExcerptId,
 407    /// The location of the last [`Excerpt`] being summarized
 408    excerpt_locator: Locator,
 409    widest_line_number: u32,
 410    text: TextSummary,
 411}
 412
 413#[derive(Debug, Clone)]
 414pub struct DiffTransformSummary {
 415    input: TextSummary,
 416    output: TextSummary,
 417}
 418
 419#[derive(Clone)]
 420pub struct MultiBufferRows<'a> {
 421    point: Point,
 422    is_empty: bool,
 423    is_singleton: bool,
 424    cursor: MultiBufferCursor<'a, Point>,
 425}
 426
 427pub struct MultiBufferChunks<'a> {
 428    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 429    diff_transforms: Cursor<'a, 'static, DiffTransform, Dimensions<usize, ExcerptOffset>>,
 430    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 431    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 432    buffer_chunk: Option<Chunk<'a>>,
 433    range: Range<usize>,
 434    excerpt_offset_range: Range<ExcerptOffset>,
 435    excerpt_chunks: Option<ExcerptChunks<'a>>,
 436    language_aware: bool,
 437}
 438
 439pub struct ReversedMultiBufferChunks<'a> {
 440    cursor: MultiBufferCursor<'a, usize>,
 441    current_chunks: Option<rope::Chunks<'a>>,
 442    start: usize,
 443    offset: usize,
 444}
 445
 446pub struct MultiBufferBytes<'a> {
 447    range: Range<usize>,
 448    cursor: MultiBufferCursor<'a, usize>,
 449    excerpt_bytes: Option<text::Bytes<'a>>,
 450    has_trailing_newline: bool,
 451    chunk: &'a [u8],
 452}
 453
 454pub struct ReversedMultiBufferBytes<'a> {
 455    range: Range<usize>,
 456    chunks: ReversedMultiBufferChunks<'a>,
 457    chunk: &'a [u8],
 458}
 459
 460#[derive(Clone)]
 461struct DiffTransforms<D> {
 462    output_dimension: OutputDimension<D>,
 463    excerpt_dimension: ExcerptDimension<D>,
 464}
 465
 466impl<'a, D: TextDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<D> {
 467    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
 468        Self {
 469            output_dimension: OutputDimension::zero(cx),
 470            excerpt_dimension: <ExcerptDimension<D> as Dimension<'a, DiffTransformSummary>>::zero(
 471                cx,
 472            ),
 473        }
 474    }
 475
 476    fn add_summary(
 477        &mut self,
 478        summary: &'a DiffTransformSummary,
 479        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
 480    ) {
 481        self.output_dimension.add_summary(summary, cx);
 482        self.excerpt_dimension.add_summary(summary, cx);
 483    }
 484}
 485
 486#[derive(Clone)]
 487struct MultiBufferCursor<'a, D: TextDimension> {
 488    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<D>>,
 489    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<D>>,
 490    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 491    cached_region: Option<MultiBufferRegion<'a, D>>,
 492}
 493
 494#[derive(Clone)]
 495struct MultiBufferRegion<'a, D: TextDimension> {
 496    buffer: &'a BufferSnapshot,
 497    is_main_buffer: bool,
 498    diff_hunk_status: Option<DiffHunkStatus>,
 499    excerpt: &'a Excerpt,
 500    buffer_range: Range<D>,
 501    range: Range<D>,
 502    has_trailing_newline: bool,
 503}
 504
 505struct ExcerptChunks<'a> {
 506    excerpt_id: ExcerptId,
 507    content_chunks: BufferChunks<'a>,
 508    has_footer: bool,
 509}
 510
 511#[derive(Debug)]
 512struct BufferEdit {
 513    range: Range<usize>,
 514    new_text: Arc<str>,
 515    is_insertion: bool,
 516    original_indent_column: Option<u32>,
 517    excerpt_id: ExcerptId,
 518}
 519
 520#[derive(Clone, Copy, Debug, PartialEq)]
 521enum DiffChangeKind {
 522    BufferEdited,
 523    DiffUpdated { base_changed: bool },
 524    ExpandOrCollapseHunks { expand: bool },
 525}
 526
 527#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 528pub enum ExpandExcerptDirection {
 529    Up,
 530    Down,
 531    UpAndDown,
 532}
 533
 534impl ExpandExcerptDirection {
 535    pub fn should_expand_up(&self) -> bool {
 536        match self {
 537            ExpandExcerptDirection::Up => true,
 538            ExpandExcerptDirection::Down => false,
 539            ExpandExcerptDirection::UpAndDown => true,
 540        }
 541    }
 542
 543    pub fn should_expand_down(&self) -> bool {
 544        match self {
 545            ExpandExcerptDirection::Up => false,
 546            ExpandExcerptDirection::Down => true,
 547            ExpandExcerptDirection::UpAndDown => true,
 548        }
 549    }
 550}
 551
 552#[derive(Clone, Debug, PartialEq)]
 553pub struct IndentGuide {
 554    pub buffer_id: BufferId,
 555    pub start_row: MultiBufferRow,
 556    pub end_row: MultiBufferRow,
 557    pub depth: u32,
 558    pub tab_size: u32,
 559    pub settings: IndentGuideSettings,
 560}
 561
 562impl IndentGuide {
 563    pub fn indent_level(&self) -> u32 {
 564        self.depth * self.tab_size
 565    }
 566}
 567
 568impl MultiBuffer {
 569    pub fn new(capability: Capability) -> Self {
 570        Self::new_(
 571            capability,
 572            MultiBufferSnapshot {
 573                show_headers: true,
 574                ..MultiBufferSnapshot::default()
 575            },
 576        )
 577    }
 578
 579    pub fn without_headers(capability: Capability) -> Self {
 580        Self::new_(capability, Default::default())
 581    }
 582
 583    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 584        let mut this = Self::new_(
 585            buffer.read(cx).capability(),
 586            MultiBufferSnapshot {
 587                singleton: true,
 588                ..MultiBufferSnapshot::default()
 589            },
 590        );
 591        this.singleton = true;
 592        this.push_excerpts(
 593            buffer,
 594            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 595            cx,
 596        );
 597        this
 598    }
 599
 600    #[inline]
 601    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
 602        Self {
 603            snapshot: RefCell::new(snapshot),
 604            buffers: Default::default(),
 605            diffs: HashMap::default(),
 606            subscriptions: Topic::default(),
 607            singleton: false,
 608            capability,
 609            title: None,
 610            excerpts_by_path: Default::default(),
 611            paths_by_excerpt: Default::default(),
 612            buffer_changed_since_sync: Default::default(),
 613            history: History::default(),
 614        }
 615    }
 616
 617    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 618        let mut buffers = HashMap::default();
 619        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 620        for (buffer_id, buffer_state) in self.buffers.iter() {
 621            buffer_state.buffer.update(new_cx, |buffer, _| {
 622                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 623            });
 624            buffers.insert(
 625                *buffer_id,
 626                BufferState {
 627                    buffer: buffer_state.buffer.clone(),
 628                    last_version: buffer_state.last_version.clone(),
 629                    last_non_text_state_update_count: buffer_state
 630                        .last_non_text_state_update_count
 631                        .clone(),
 632                    excerpts: buffer_state.excerpts.clone(),
 633                    _subscriptions: [
 634                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 635                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 636                    ],
 637                },
 638            );
 639        }
 640        let mut diff_bases = HashMap::default();
 641        for (buffer_id, diff) in self.diffs.iter() {
 642            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 643        }
 644        Self {
 645            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 646            buffers: buffers,
 647            excerpts_by_path: Default::default(),
 648            paths_by_excerpt: Default::default(),
 649            diffs: diff_bases,
 650            subscriptions: Default::default(),
 651            singleton: self.singleton,
 652            capability: self.capability,
 653            history: self.history.clone(),
 654            title: self.title.clone(),
 655            buffer_changed_since_sync,
 656        }
 657    }
 658
 659    pub fn set_group_interval(&mut self, group_interval: Duration) {
 660        self.history.set_group_interval(group_interval);
 661    }
 662
 663    pub fn with_title(mut self, title: String) -> Self {
 664        self.title = Some(title);
 665        self
 666    }
 667
 668    pub fn read_only(&self) -> bool {
 669        self.capability == Capability::ReadOnly
 670    }
 671
 672    /// Returns an up-to-date snapshot of the MultiBuffer.
 673    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 674        self.sync(cx);
 675        self.snapshot.borrow().clone()
 676    }
 677
 678    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 679        self.sync(cx);
 680        self.snapshot.borrow()
 681    }
 682
 683    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 684        if self.singleton {
 685            Some(self.buffers.values().next().unwrap().buffer.clone())
 686        } else {
 687            None
 688        }
 689    }
 690
 691    pub fn is_singleton(&self) -> bool {
 692        self.singleton
 693    }
 694
 695    pub fn subscribe(&mut self) -> Subscription {
 696        self.subscriptions.subscribe()
 697    }
 698
 699    pub fn is_dirty(&self, cx: &App) -> bool {
 700        self.read(cx).is_dirty()
 701    }
 702
 703    pub fn has_deleted_file(&self, cx: &App) -> bool {
 704        self.read(cx).has_deleted_file()
 705    }
 706
 707    pub fn has_conflict(&self, cx: &App) -> bool {
 708        self.read(cx).has_conflict()
 709    }
 710
 711    // The `is_empty` signature doesn't match what clippy expects
 712    #[allow(clippy::len_without_is_empty)]
 713    pub fn len(&self, cx: &App) -> usize {
 714        self.read(cx).len()
 715    }
 716
 717    pub fn is_empty(&self) -> bool {
 718        self.buffers.is_empty()
 719    }
 720
 721    pub fn edit<I, S, T>(
 722        &mut self,
 723        edits: I,
 724        autoindent_mode: Option<AutoindentMode>,
 725        cx: &mut Context<Self>,
 726    ) where
 727        I: IntoIterator<Item = (Range<S>, T)>,
 728        S: ToOffset,
 729        T: Into<Arc<str>>,
 730    {
 731        if self.read_only() || self.buffers.is_empty() {
 732            return;
 733        }
 734        self.sync_mut(cx);
 735        let edits = edits
 736            .into_iter()
 737            .map(|(range, new_text)| {
 738                let mut range = range.start.to_offset(self.snapshot.get_mut())
 739                    ..range.end.to_offset(self.snapshot.get_mut());
 740                if range.start > range.end {
 741                    mem::swap(&mut range.start, &mut range.end);
 742                }
 743                (range, new_text.into())
 744            })
 745            .collect::<Vec<_>>();
 746
 747        return edit_internal(self, edits, autoindent_mode, cx);
 748
 749        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 750        fn edit_internal(
 751            this: &mut MultiBuffer,
 752            edits: Vec<(Range<usize>, Arc<str>)>,
 753            mut autoindent_mode: Option<AutoindentMode>,
 754            cx: &mut Context<MultiBuffer>,
 755        ) {
 756            let original_indent_columns = match &mut autoindent_mode {
 757                Some(AutoindentMode::Block {
 758                    original_indent_columns,
 759                }) => mem::take(original_indent_columns),
 760                _ => Default::default(),
 761            };
 762
 763            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
 764                edits,
 765                this.snapshot.get_mut(),
 766                &original_indent_columns,
 767            );
 768
 769            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
 770            for (buffer_id, mut edits) in buffer_edits {
 771                buffer_ids.push(buffer_id);
 772                edits.sort_by_key(|edit| edit.range.start);
 773                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
 774                    let mut edits = edits.into_iter().peekable();
 775                    let mut insertions = Vec::new();
 776                    let mut original_indent_columns = Vec::new();
 777                    let mut deletions = Vec::new();
 778                    let empty_str: Arc<str> = Arc::default();
 779                    while let Some(BufferEdit {
 780                        mut range,
 781                        mut new_text,
 782                        mut is_insertion,
 783                        original_indent_column,
 784                        excerpt_id,
 785                    }) = edits.next()
 786                    {
 787                        while let Some(BufferEdit {
 788                            range: next_range,
 789                            is_insertion: next_is_insertion,
 790                            new_text: next_new_text,
 791                            excerpt_id: next_excerpt_id,
 792                            ..
 793                        }) = edits.peek()
 794                        {
 795                            if range.end >= next_range.start {
 796                                range.end = cmp::max(next_range.end, range.end);
 797                                is_insertion |= *next_is_insertion;
 798                                if excerpt_id == *next_excerpt_id {
 799                                    new_text = format!("{new_text}{next_new_text}").into();
 800                                }
 801                                edits.next();
 802                            } else {
 803                                break;
 804                            }
 805                        }
 806
 807                        if is_insertion {
 808                            original_indent_columns.push(original_indent_column);
 809                            insertions.push((
 810                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 811                                new_text.clone(),
 812                            ));
 813                        } else if !range.is_empty() {
 814                            deletions.push((
 815                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 816                                empty_str.clone(),
 817                            ));
 818                        }
 819                    }
 820
 821                    let deletion_autoindent_mode =
 822                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 823                            Some(AutoindentMode::Block {
 824                                original_indent_columns: Default::default(),
 825                            })
 826                        } else {
 827                            autoindent_mode.clone()
 828                        };
 829                    let insertion_autoindent_mode =
 830                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 831                            Some(AutoindentMode::Block {
 832                                original_indent_columns,
 833                            })
 834                        } else {
 835                            autoindent_mode.clone()
 836                        };
 837
 838                    buffer.edit(deletions, deletion_autoindent_mode, cx);
 839                    buffer.edit(insertions, insertion_autoindent_mode, cx);
 840                })
 841            }
 842
 843            cx.emit(Event::ExcerptsEdited {
 844                excerpt_ids: edited_excerpt_ids,
 845                buffer_ids,
 846            });
 847        }
 848    }
 849
 850    fn convert_edits_to_buffer_edits(
 851        edits: Vec<(Range<usize>, Arc<str>)>,
 852        snapshot: &MultiBufferSnapshot,
 853        original_indent_columns: &[Option<u32>],
 854    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 855        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 856        let mut edited_excerpt_ids = Vec::new();
 857        let mut cursor = snapshot.cursor::<usize>();
 858        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 859            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 860
 861            cursor.seek(&range.start);
 862            let mut start_region = cursor.region().expect("start offset out of bounds");
 863            if !start_region.is_main_buffer {
 864                cursor.next();
 865                if let Some(region) = cursor.region() {
 866                    start_region = region;
 867                } else {
 868                    continue;
 869                }
 870            }
 871
 872            if range.end < start_region.range.start {
 873                continue;
 874            }
 875
 876            if range.end > start_region.range.end {
 877                cursor.seek_forward(&range.end);
 878            }
 879            let mut end_region = cursor.region().expect("end offset out of bounds");
 880            if !end_region.is_main_buffer {
 881                cursor.prev();
 882                if let Some(region) = cursor.region() {
 883                    end_region = region;
 884                } else {
 885                    continue;
 886                }
 887            }
 888
 889            if range.start > end_region.range.end {
 890                continue;
 891            }
 892
 893            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 894            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 895            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 896                .min(start_region.buffer_range.end);
 897            let buffer_end =
 898                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 899
 900            if start_region.excerpt.id == end_region.excerpt.id {
 901                if start_region.is_main_buffer {
 902                    edited_excerpt_ids.push(start_region.excerpt.id);
 903                    buffer_edits
 904                        .entry(start_region.buffer.remote_id())
 905                        .or_default()
 906                        .push(BufferEdit {
 907                            range: buffer_start..buffer_end,
 908                            new_text,
 909                            is_insertion: true,
 910                            original_indent_column,
 911                            excerpt_id: start_region.excerpt.id,
 912                        });
 913                }
 914            } else {
 915                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 916                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 917                if start_region.is_main_buffer {
 918                    edited_excerpt_ids.push(start_region.excerpt.id);
 919                    buffer_edits
 920                        .entry(start_region.buffer.remote_id())
 921                        .or_default()
 922                        .push(BufferEdit {
 923                            range: start_excerpt_range,
 924                            new_text: new_text.clone(),
 925                            is_insertion: true,
 926                            original_indent_column,
 927                            excerpt_id: start_region.excerpt.id,
 928                        });
 929                }
 930                if end_region.is_main_buffer {
 931                    edited_excerpt_ids.push(end_region.excerpt.id);
 932                    buffer_edits
 933                        .entry(end_region.buffer.remote_id())
 934                        .or_default()
 935                        .push(BufferEdit {
 936                            range: end_excerpt_range,
 937                            new_text: new_text.clone(),
 938                            is_insertion: false,
 939                            original_indent_column,
 940                            excerpt_id: end_region.excerpt.id,
 941                        });
 942                }
 943
 944                cursor.seek(&range.start);
 945                cursor.next_excerpt();
 946                while let Some(region) = cursor.region() {
 947                    if region.excerpt.id == end_region.excerpt.id {
 948                        break;
 949                    }
 950                    if region.is_main_buffer {
 951                        edited_excerpt_ids.push(region.excerpt.id);
 952                        buffer_edits
 953                            .entry(region.buffer.remote_id())
 954                            .or_default()
 955                            .push(BufferEdit {
 956                                range: region.buffer_range,
 957                                new_text: new_text.clone(),
 958                                is_insertion: false,
 959                                original_indent_column,
 960                                excerpt_id: region.excerpt.id,
 961                            });
 962                    }
 963                    cursor.next_excerpt();
 964                }
 965            }
 966        }
 967        (buffer_edits, edited_excerpt_ids)
 968    }
 969
 970    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
 971    where
 972        I: IntoIterator<Item = Range<S>>,
 973        S: ToOffset,
 974    {
 975        if self.read_only() || self.buffers.is_empty() {
 976            return;
 977        }
 978        self.sync_mut(cx);
 979        let empty = Arc::<str>::from("");
 980        let edits = ranges
 981            .into_iter()
 982            .map(|range| {
 983                let mut range = range.start.to_offset(self.snapshot.get_mut())
 984                    ..range.end.to_offset(&self.snapshot.get_mut());
 985                if range.start > range.end {
 986                    mem::swap(&mut range.start, &mut range.end);
 987                }
 988                (range, empty.clone())
 989            })
 990            .collect::<Vec<_>>();
 991
 992        return autoindent_ranges_internal(self, edits, cx);
 993
 994        fn autoindent_ranges_internal(
 995            this: &mut MultiBuffer,
 996            edits: Vec<(Range<usize>, Arc<str>)>,
 997            cx: &mut Context<MultiBuffer>,
 998        ) {
 999            let (buffer_edits, edited_excerpt_ids) =
1000                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1001
1002            let mut buffer_ids = Vec::new();
1003            for (buffer_id, mut edits) in buffer_edits {
1004                buffer_ids.push(buffer_id);
1005                edits.sort_unstable_by_key(|edit| edit.range.start);
1006
1007                let mut ranges: Vec<Range<usize>> = Vec::new();
1008                for edit in edits {
1009                    if let Some(last_range) = ranges.last_mut()
1010                        && edit.range.start <= last_range.end
1011                    {
1012                        last_range.end = last_range.end.max(edit.range.end);
1013                        continue;
1014                    }
1015                    ranges.push(edit.range);
1016                }
1017
1018                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1019                    buffer.autoindent_ranges(ranges, cx);
1020                })
1021            }
1022
1023            cx.emit(Event::ExcerptsEdited {
1024                excerpt_ids: edited_excerpt_ids,
1025                buffer_ids,
1026            });
1027        }
1028    }
1029
1030    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1031    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1032    /// Panics if the given position is invalid.
1033    pub fn insert_empty_line(
1034        &mut self,
1035        position: impl ToPoint,
1036        space_above: bool,
1037        space_below: bool,
1038        cx: &mut Context<Self>,
1039    ) -> Point {
1040        let multibuffer_point = position.to_point(&self.read(cx));
1041        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1042        self.start_transaction(cx);
1043        let empty_line_start = buffer.update(cx, |buffer, cx| {
1044            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1045        });
1046        self.end_transaction(cx);
1047        multibuffer_point + (empty_line_start - buffer_point)
1048    }
1049
1050    pub fn set_active_selections(
1051        &self,
1052        selections: &[Selection<Anchor>],
1053        line_mode: bool,
1054        cursor_shape: CursorShape,
1055        cx: &mut Context<Self>,
1056    ) {
1057        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1058            Default::default();
1059        let snapshot = self.read(cx);
1060        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1061        for selection in selections {
1062            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1063            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1064
1065            cursor.seek(&Some(start_locator), Bias::Left);
1066            while let Some(excerpt) = cursor.item()
1067                && excerpt.locator <= *end_locator
1068            {
1069                let mut start = excerpt.range.context.start;
1070                let mut end = excerpt.range.context.end;
1071                if excerpt.id == selection.start.excerpt_id {
1072                    start = selection.start.text_anchor;
1073                }
1074                if excerpt.id == selection.end.excerpt_id {
1075                    end = selection.end.text_anchor;
1076                }
1077                selections_by_buffer
1078                    .entry(excerpt.buffer_id)
1079                    .or_default()
1080                    .push(Selection {
1081                        id: selection.id,
1082                        start,
1083                        end,
1084                        reversed: selection.reversed,
1085                        goal: selection.goal,
1086                    });
1087
1088                cursor.next();
1089            }
1090        }
1091
1092        for (buffer_id, buffer_state) in self.buffers.iter() {
1093            if !selections_by_buffer.contains_key(buffer_id) {
1094                buffer_state
1095                    .buffer
1096                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1097            }
1098        }
1099
1100        for (buffer_id, mut selections) in selections_by_buffer {
1101            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1102                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1103                let mut selections = selections.into_iter().peekable();
1104                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1105                    let mut selection = selections.next()?;
1106                    while let Some(next_selection) = selections.peek() {
1107                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1108                            let next_selection = selections.next().unwrap();
1109                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1110                                selection.end = next_selection.end;
1111                            }
1112                        } else {
1113                            break;
1114                        }
1115                    }
1116                    Some(selection)
1117                }));
1118                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1119            });
1120        }
1121    }
1122
1123    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1124        for buffer in self.buffers.values() {
1125            buffer
1126                .buffer
1127                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1128        }
1129    }
1130
1131    pub fn push_excerpts<O>(
1132        &mut self,
1133        buffer: Entity<Buffer>,
1134        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1135        cx: &mut Context<Self>,
1136    ) -> Vec<ExcerptId>
1137    where
1138        O: text::ToOffset,
1139    {
1140        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1141    }
1142
1143    fn merge_excerpt_ranges<'a>(
1144        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1145    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1146        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1147        let mut counts: Vec<usize> = Vec::new();
1148        for range in expanded_ranges {
1149            if let Some(last_range) = merged_ranges.last_mut() {
1150                debug_assert!(
1151                    last_range.context.start <= range.context.start,
1152                    "Last range: {last_range:?} Range: {range:?}"
1153                );
1154                if last_range.context.end >= range.context.start
1155                    || last_range.context.end.row + 1 == range.context.start.row
1156                {
1157                    last_range.context.end = range.context.end.max(last_range.context.end);
1158                    *counts.last_mut().unwrap() += 1;
1159                    continue;
1160                }
1161            }
1162            merged_ranges.push(range.clone());
1163            counts.push(1);
1164        }
1165        (merged_ranges, counts)
1166    }
1167
1168    pub fn insert_excerpts_after<O>(
1169        &mut self,
1170        prev_excerpt_id: ExcerptId,
1171        buffer: Entity<Buffer>,
1172        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1173        cx: &mut Context<Self>,
1174    ) -> Vec<ExcerptId>
1175    where
1176        O: text::ToOffset,
1177    {
1178        let mut ids = Vec::new();
1179        let mut next_excerpt_id =
1180            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1181                last_entry.id.0 + 1
1182            } else {
1183                1
1184            };
1185        self.insert_excerpts_with_ids_after(
1186            prev_excerpt_id,
1187            buffer,
1188            ranges.into_iter().map(|range| {
1189                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1190                ids.push(id);
1191                (id, range)
1192            }),
1193            cx,
1194        );
1195        ids
1196    }
1197
1198    pub fn insert_excerpts_with_ids_after<O>(
1199        &mut self,
1200        prev_excerpt_id: ExcerptId,
1201        buffer: Entity<Buffer>,
1202        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1203        cx: &mut Context<Self>,
1204    ) where
1205        O: text::ToOffset,
1206    {
1207        assert_eq!(self.history.transaction_depth(), 0);
1208        let mut ranges = ranges.into_iter().peekable();
1209        if ranges.peek().is_none() {
1210            return Default::default();
1211        }
1212
1213        self.sync_mut(cx);
1214
1215        let buffer_snapshot = buffer.read(cx).snapshot();
1216        let buffer_id = buffer_snapshot.remote_id();
1217
1218        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1219            self.buffer_changed_since_sync.replace(true);
1220            buffer.update(cx, |buffer, _| {
1221                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1222            });
1223            BufferState {
1224                last_version: RefCell::new(buffer_snapshot.version().clone()),
1225                last_non_text_state_update_count: Cell::new(
1226                    buffer_snapshot.non_text_state_update_count(),
1227                ),
1228                excerpts: Default::default(),
1229                _subscriptions: [
1230                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1231                    cx.subscribe(&buffer, Self::on_buffer_event),
1232                ],
1233                buffer: buffer.clone(),
1234            }
1235        });
1236
1237        let mut snapshot = self.snapshot.get_mut();
1238
1239        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1240        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1241        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1242        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1243        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1244
1245        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1246        new_excerpts.update_last(
1247            |excerpt| {
1248                excerpt.has_trailing_newline = true;
1249            },
1250            (),
1251        );
1252
1253        let next_locator = if let Some(excerpt) = cursor.item() {
1254            excerpt.locator.clone()
1255        } else {
1256            Locator::max()
1257        };
1258
1259        let mut excerpts = Vec::new();
1260        while let Some((id, range)) = ranges.next() {
1261            let locator = Locator::between(&prev_locator, &next_locator);
1262            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1263                buffer_state.excerpts.insert(ix, locator.clone());
1264            }
1265            let range = ExcerptRange {
1266                context: buffer_snapshot.anchor_before(&range.context.start)
1267                    ..buffer_snapshot.anchor_after(&range.context.end),
1268                primary: buffer_snapshot.anchor_before(&range.primary.start)
1269                    ..buffer_snapshot.anchor_after(&range.primary.end),
1270            };
1271            excerpts.push((id, range.clone()));
1272            let excerpt = Excerpt::new(
1273                id,
1274                locator.clone(),
1275                buffer_id,
1276                buffer_snapshot.clone(),
1277                range,
1278                ranges.peek().is_some() || cursor.item().is_some(),
1279            );
1280            new_excerpts.push(excerpt, ());
1281            prev_locator = locator.clone();
1282
1283            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1284                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1285            }
1286            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1287        }
1288
1289        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1290
1291        let suffix = cursor.suffix();
1292        let changed_trailing_excerpt = suffix.is_empty();
1293        new_excerpts.append(suffix, ());
1294        drop(cursor);
1295        snapshot.excerpts = new_excerpts;
1296        snapshot.excerpt_ids = new_excerpt_ids;
1297        if changed_trailing_excerpt {
1298            snapshot.trailing_excerpt_update_count += 1;
1299        }
1300
1301        let edits = Self::sync_diff_transforms(
1302            &mut snapshot,
1303            vec![Edit {
1304                old: edit_start..edit_start,
1305                new: edit_start..edit_end,
1306            }],
1307            DiffChangeKind::BufferEdited,
1308        );
1309        if !edits.is_empty() {
1310            self.subscriptions.publish(edits);
1311        }
1312
1313        cx.emit(Event::Edited {
1314            edited_buffer: None,
1315        });
1316        cx.emit(Event::ExcerptsAdded {
1317            buffer,
1318            predecessor: prev_excerpt_id,
1319            excerpts,
1320        });
1321        cx.notify();
1322    }
1323
1324    pub fn clear(&mut self, cx: &mut Context<Self>) {
1325        self.sync_mut(cx);
1326        let ids = self.excerpt_ids();
1327        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1328        self.excerpts_by_path.clear();
1329        self.paths_by_excerpt.clear();
1330        let MultiBufferSnapshot {
1331            excerpts,
1332            diffs: _,
1333            diff_transforms: _,
1334            non_text_state_update_count: _,
1335            edit_count: _,
1336            is_dirty,
1337            has_deleted_file,
1338            has_conflict,
1339            singleton: _,
1340            excerpt_ids: _,
1341            replaced_excerpts,
1342            trailing_excerpt_update_count,
1343            all_diff_hunks_expanded: _,
1344            show_headers: _,
1345        } = self.snapshot.get_mut();
1346        let start = ExcerptOffset::new(0);
1347        let prev_len = ExcerptOffset::new(excerpts.summary().text.len);
1348        *excerpts = Default::default();
1349        *trailing_excerpt_update_count += 1;
1350        *is_dirty = false;
1351        *has_deleted_file = false;
1352        *has_conflict = false;
1353        replaced_excerpts.clear();
1354
1355        let edits = Self::sync_diff_transforms(
1356            self.snapshot.get_mut(),
1357            vec![Edit {
1358                old: start..prev_len,
1359                new: start..start,
1360            }],
1361            DiffChangeKind::BufferEdited,
1362        );
1363        if !edits.is_empty() {
1364            self.subscriptions.publish(edits);
1365        }
1366        cx.emit(Event::Edited {
1367            edited_buffer: None,
1368        });
1369        cx.emit(Event::ExcerptsRemoved {
1370            ids,
1371            removed_buffer_ids,
1372        });
1373        cx.notify();
1374    }
1375
1376    pub fn excerpts_for_buffer(
1377        &self,
1378        buffer_id: BufferId,
1379        cx: &App,
1380    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1381        let mut excerpts = Vec::new();
1382        let snapshot = self.read(cx);
1383        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1384        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1385            for locator in locators {
1386                cursor.seek_forward(&Some(locator), Bias::Left);
1387                if let Some(excerpt) = cursor.item()
1388                    && excerpt.locator == *locator
1389                {
1390                    excerpts.push((excerpt.id, excerpt.range.clone()));
1391                }
1392            }
1393        }
1394
1395        excerpts
1396    }
1397
1398    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1399        let snapshot = self.read(cx);
1400        let mut excerpts = snapshot
1401            .excerpts
1402            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
1403        let mut diff_transforms = snapshot
1404            .diff_transforms
1405            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
1406        diff_transforms.next();
1407        let locators = self
1408            .buffers
1409            .get(&buffer_id)
1410            .into_iter()
1411            .flat_map(|state| &state.excerpts);
1412        let mut result = Vec::new();
1413        for locator in locators {
1414            excerpts.seek_forward(&Some(locator), Bias::Left);
1415            if let Some(excerpt) = excerpts.item()
1416                && excerpt.locator == *locator
1417            {
1418                let excerpt_start = excerpts.start().1.clone();
1419                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1420
1421                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1422                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
1423                let start = diff_transforms.start().1.0 + overshoot;
1424
1425                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1426                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
1427                let end = diff_transforms.start().1.0 + overshoot;
1428
1429                result.push(start..end)
1430            }
1431        }
1432        result
1433    }
1434
1435    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1436        self.snapshot
1437            .borrow()
1438            .excerpts
1439            .iter()
1440            .map(|entry| entry.buffer_id)
1441            .collect()
1442    }
1443
1444    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1445        self.snapshot
1446            .borrow()
1447            .excerpts
1448            .iter()
1449            .map(|entry| entry.id)
1450            .collect()
1451    }
1452
1453    pub fn excerpt_containing(
1454        &self,
1455        position: impl ToOffset,
1456        cx: &App,
1457    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1458        let snapshot = self.read(cx);
1459        let offset = position.to_offset(&snapshot);
1460
1461        let mut cursor = snapshot.cursor::<usize>();
1462        cursor.seek(&offset);
1463        cursor
1464            .excerpt()
1465            .or_else(|| snapshot.excerpts.last())
1466            .map(|excerpt| {
1467                (
1468                    excerpt.id,
1469                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
1470                    excerpt.range.context.clone(),
1471                )
1472            })
1473    }
1474
1475    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1476        if let Some(buffer_id) = anchor.buffer_id {
1477            self.buffer(buffer_id)
1478        } else {
1479            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
1480            Some(buffer)
1481        }
1482    }
1483
1484    // If point is at the end of the buffer, the last excerpt is returned
1485    pub fn point_to_buffer_offset<T: ToOffset>(
1486        &self,
1487        point: T,
1488        cx: &App,
1489    ) -> Option<(Entity<Buffer>, usize)> {
1490        let snapshot = self.read(cx);
1491        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1492        Some((
1493            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1494            offset,
1495        ))
1496    }
1497
1498    // If point is at the end of the buffer, the last excerpt is returned
1499    pub fn point_to_buffer_point<T: ToPoint>(
1500        &self,
1501        point: T,
1502        cx: &App,
1503    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1504        let snapshot = self.read(cx);
1505        let (buffer, point, is_main_buffer) =
1506            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1507        Some((
1508            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1509            point,
1510            is_main_buffer,
1511        ))
1512    }
1513
1514    pub fn buffer_point_to_anchor(
1515        &self,
1516        buffer: &Entity<Buffer>,
1517        point: Point,
1518        cx: &App,
1519    ) -> Option<Anchor> {
1520        let mut found = None;
1521        let snapshot = buffer.read(cx).snapshot();
1522        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1523            let start = range.context.start.to_point(&snapshot);
1524            let end = range.context.end.to_point(&snapshot);
1525            if start <= point && point < end {
1526                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1527                break;
1528            }
1529            if point < start {
1530                found = Some((start, excerpt_id));
1531            }
1532            if point > end {
1533                found = Some((end, excerpt_id));
1534            }
1535        }
1536
1537        found.map(|(point, excerpt_id)| {
1538            let text_anchor = snapshot.anchor_after(point);
1539            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
1540        })
1541    }
1542
1543    pub fn buffer_anchor_to_anchor(
1544        &self,
1545        buffer: &Entity<Buffer>,
1546        anchor: text::Anchor,
1547        cx: &App,
1548    ) -> Option<Anchor> {
1549        let snapshot = buffer.read(cx).snapshot();
1550        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1551            if range.context.start.cmp(&anchor, &snapshot).is_le()
1552                && range.context.end.cmp(&anchor, &snapshot).is_ge()
1553            {
1554                return Some(Anchor::in_buffer(excerpt_id, snapshot.remote_id(), anchor));
1555            }
1556        }
1557
1558        None
1559    }
1560
1561    pub fn remove_excerpts(
1562        &mut self,
1563        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1564        cx: &mut Context<Self>,
1565    ) {
1566        self.sync_mut(cx);
1567        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1568        if ids.is_empty() {
1569            return;
1570        }
1571        self.buffer_changed_since_sync.replace(true);
1572
1573        let mut snapshot = self.snapshot.get_mut();
1574        let mut new_excerpts = SumTree::default();
1575        let mut cursor = snapshot
1576            .excerpts
1577            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1578        let mut edits = Vec::new();
1579        let mut excerpt_ids = ids.iter().copied().peekable();
1580        let mut removed_buffer_ids = Vec::new();
1581
1582        while let Some(excerpt_id) = excerpt_ids.next() {
1583            self.paths_by_excerpt.remove(&excerpt_id);
1584            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1585            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1586            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
1587
1588            if let Some(mut excerpt) = cursor.item() {
1589                if excerpt.id != excerpt_id {
1590                    continue;
1591                }
1592                let mut old_start = cursor.start().1;
1593
1594                // Skip over the removed excerpt.
1595                'remove_excerpts: loop {
1596                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
1597                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1598                        if buffer_state.excerpts.is_empty() {
1599                            log::debug!(
1600                                "removing buffer and diff for buffer {}",
1601                                excerpt.buffer_id
1602                            );
1603                            self.buffers.remove(&excerpt.buffer_id);
1604                            removed_buffer_ids.push(excerpt.buffer_id);
1605                        }
1606                    }
1607                    cursor.next();
1608
1609                    // Skip over any subsequent excerpts that are also removed.
1610                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1611                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1612                        if let Some(next_excerpt) = cursor.item()
1613                            && next_excerpt.locator == *next_locator
1614                        {
1615                            excerpt_ids.next();
1616                            excerpt = next_excerpt;
1617                            continue 'remove_excerpts;
1618                        }
1619                    }
1620
1621                    break;
1622                }
1623
1624                // When removing the last excerpt, remove the trailing newline from
1625                // the previous excerpt.
1626                if cursor.item().is_none() && old_start.value > 0 {
1627                    old_start.value -= 1;
1628                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
1629                }
1630
1631                // Push an edit for the removal of this run of excerpts.
1632                let old_end = cursor.start().1;
1633                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1634                edits.push(Edit {
1635                    old: old_start..old_end,
1636                    new: new_start..new_start,
1637                });
1638            }
1639        }
1640        let suffix = cursor.suffix();
1641        let changed_trailing_excerpt = suffix.is_empty();
1642        new_excerpts.append(suffix, ());
1643        drop(cursor);
1644        snapshot.excerpts = new_excerpts;
1645        for buffer_id in &removed_buffer_ids {
1646            self.diffs.remove(buffer_id);
1647            snapshot.diffs.remove(buffer_id);
1648        }
1649
1650        if changed_trailing_excerpt {
1651            snapshot.trailing_excerpt_update_count += 1;
1652        }
1653
1654        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
1655        if !edits.is_empty() {
1656            self.subscriptions.publish(edits);
1657        }
1658        cx.emit(Event::Edited {
1659            edited_buffer: None,
1660        });
1661        cx.emit(Event::ExcerptsRemoved {
1662            ids,
1663            removed_buffer_ids,
1664        });
1665        cx.notify();
1666    }
1667
1668    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1669        &self,
1670        anchors: Anchors,
1671        cx: &mut Context<Self>,
1672    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1673        let mut error = None;
1674        let mut futures = Vec::new();
1675        for anchor in anchors {
1676            if let Some(buffer_id) = anchor.buffer_id {
1677                if let Some(buffer) = self.buffers.get(&buffer_id) {
1678                    buffer.buffer.update(cx, |buffer, _| {
1679                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1680                    });
1681                } else {
1682                    error = Some(anyhow!(
1683                        "buffer {buffer_id} is not part of this multi-buffer"
1684                    ));
1685                    break;
1686                }
1687            }
1688        }
1689        async move {
1690            if let Some(error) = error {
1691                Err(error)?;
1692            }
1693            for future in futures {
1694                future.await?;
1695            }
1696            Ok(())
1697        }
1698    }
1699
1700    pub fn text_anchor_for_position<T: ToOffset>(
1701        &self,
1702        position: T,
1703        cx: &App,
1704    ) -> Option<(Entity<Buffer>, language::Anchor)> {
1705        let snapshot = self.read(cx);
1706        let anchor = snapshot.anchor_before(position);
1707        let buffer = self.buffers.get(&anchor.buffer_id?)?.buffer.clone();
1708        Some((buffer, anchor.text_anchor))
1709    }
1710
1711    fn on_buffer_event(
1712        &mut self,
1713        buffer: Entity<Buffer>,
1714        event: &language::BufferEvent,
1715        cx: &mut Context<Self>,
1716    ) {
1717        use language::BufferEvent;
1718        cx.emit(match event {
1719            BufferEvent::Edited => Event::Edited {
1720                edited_buffer: Some(buffer),
1721            },
1722            BufferEvent::DirtyChanged => Event::DirtyChanged,
1723            BufferEvent::Saved => Event::Saved,
1724            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1725            BufferEvent::Reloaded => Event::Reloaded,
1726            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
1727            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
1728            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1729            BufferEvent::CapabilityChanged => {
1730                self.capability = buffer.read(cx).capability();
1731                return;
1732            }
1733            BufferEvent::Operation { .. }
1734            | BufferEvent::ReloadNeeded
1735            | BufferEvent::EncodingChanged => return,
1736        });
1737    }
1738
1739    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1740        let diff = diff.read(cx);
1741        let buffer_id = diff.buffer_id;
1742        let diff = diff.snapshot(cx);
1743        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
1744    }
1745
1746    fn buffer_diff_changed(
1747        &mut self,
1748        diff: Entity<BufferDiff>,
1749        range: Range<text::Anchor>,
1750        cx: &mut Context<Self>,
1751    ) {
1752        self.sync_mut(cx);
1753
1754        let diff = diff.read(cx);
1755        let buffer_id = diff.buffer_id;
1756        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
1757            return;
1758        };
1759        self.buffer_changed_since_sync.replace(true);
1760
1761        let buffer = buffer_state.buffer.read(cx);
1762        let diff_change_range = range.to_offset(buffer);
1763
1764        let new_diff = diff.snapshot(cx);
1765        let mut snapshot = self.snapshot.get_mut();
1766        let base_text_changed = snapshot
1767            .diffs
1768            .get(&buffer_id)
1769            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
1770
1771        snapshot.diffs.insert(buffer_id, new_diff);
1772
1773        let mut excerpt_edits = Vec::new();
1774        for locator in &buffer_state.excerpts {
1775            let mut cursor = snapshot
1776                .excerpts
1777                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1778            cursor.seek_forward(&Some(locator), Bias::Left);
1779            if let Some(excerpt) = cursor.item()
1780                && excerpt.locator == *locator
1781            {
1782                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
1783                if diff_change_range.end < excerpt_buffer_range.start
1784                    || diff_change_range.start > excerpt_buffer_range.end
1785                {
1786                    continue;
1787                }
1788                let excerpt_start = cursor.start().1;
1789                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
1790                let diff_change_start_in_excerpt = ExcerptOffset::new(
1791                    diff_change_range
1792                        .start
1793                        .saturating_sub(excerpt_buffer_range.start),
1794                );
1795                let diff_change_end_in_excerpt = ExcerptOffset::new(
1796                    diff_change_range
1797                        .end
1798                        .saturating_sub(excerpt_buffer_range.start),
1799                );
1800                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
1801                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
1802                excerpt_edits.push(Edit {
1803                    old: edit_start..edit_end,
1804                    new: edit_start..edit_end,
1805                });
1806            }
1807        }
1808
1809        let edits = Self::sync_diff_transforms(
1810            &mut snapshot,
1811            excerpt_edits,
1812            DiffChangeKind::DiffUpdated {
1813                base_changed: base_text_changed,
1814            },
1815        );
1816        if !edits.is_empty() {
1817            self.subscriptions.publish(edits);
1818        }
1819        cx.emit(Event::Edited {
1820            edited_buffer: None,
1821        });
1822    }
1823
1824    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
1825        self.buffers
1826            .values()
1827            .map(|state| state.buffer.clone())
1828            .collect()
1829    }
1830
1831    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
1832        self.buffers.keys().copied().collect()
1833    }
1834
1835    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
1836        self.buffers
1837            .get(&buffer_id)
1838            .map(|state| state.buffer.clone())
1839    }
1840
1841    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
1842        self.point_to_buffer_offset(point, cx)
1843            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
1844    }
1845
1846    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
1847        let buffer_id = self
1848            .snapshot
1849            .borrow()
1850            .excerpts
1851            .first()
1852            .map(|excerpt| excerpt.buffer.remote_id());
1853        buffer_id
1854            .and_then(|buffer_id| self.buffer(buffer_id))
1855            .map(|buffer| {
1856                let buffer = buffer.read(cx);
1857                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
1858            })
1859            .unwrap_or_else(move || self.language_settings_at(0, cx))
1860    }
1861
1862    pub fn language_settings_at<'a, T: ToOffset>(
1863        &'a self,
1864        point: T,
1865        cx: &'a App,
1866    ) -> Cow<'a, LanguageSettings> {
1867        let mut language = None;
1868        let mut file = None;
1869        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
1870            let buffer = buffer.read(cx);
1871            language = buffer.language_at(offset);
1872            file = buffer.file();
1873        }
1874        language_settings(language.map(|l| l.name()), file, cx)
1875    }
1876
1877    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
1878        self.buffers.values().for_each(|state| f(&state.buffer))
1879    }
1880
1881    pub fn explicit_title(&self) -> Option<&str> {
1882        self.title.as_deref()
1883    }
1884
1885    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
1886        if let Some(title) = self.title.as_ref() {
1887            return title.into();
1888        }
1889
1890        if let Some(buffer) = self.as_singleton() {
1891            let buffer = buffer.read(cx);
1892
1893            if let Some(file) = buffer.file() {
1894                return file.file_name(cx).into();
1895            }
1896
1897            if let Some(title) = self.buffer_content_title(buffer) {
1898                return title;
1899            }
1900        };
1901
1902        "untitled".into()
1903    }
1904
1905    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
1906        let mut is_leading_whitespace = true;
1907        let mut count = 0;
1908        let mut prev_was_space = false;
1909        let mut title = String::new();
1910
1911        for ch in buffer.snapshot().chars() {
1912            if is_leading_whitespace && ch.is_whitespace() {
1913                continue;
1914            }
1915
1916            is_leading_whitespace = false;
1917
1918            if ch == '\n' || count >= 40 {
1919                break;
1920            }
1921
1922            if ch.is_whitespace() {
1923                if !prev_was_space {
1924                    title.push(' ');
1925                    count += 1;
1926                    prev_was_space = true;
1927                }
1928            } else {
1929                title.push(ch);
1930                count += 1;
1931                prev_was_space = false;
1932            }
1933        }
1934
1935        let title = title.trim_end().to_string();
1936
1937        if title.is_empty() {
1938            return None;
1939        }
1940
1941        Some(title.into())
1942    }
1943
1944    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
1945        self.title = Some(title);
1946        cx.notify();
1947    }
1948
1949    /// Preserve preview tabs containing this multibuffer until additional edits occur.
1950    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
1951        for buffer_state in self.buffers.values() {
1952            buffer_state
1953                .buffer
1954                .update(cx, |buffer, _cx| buffer.refresh_preview());
1955        }
1956    }
1957
1958    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
1959    pub fn preserve_preview(&self, cx: &App) -> bool {
1960        self.buffers
1961            .values()
1962            .all(|state| state.buffer.read(cx).preserve_preview())
1963    }
1964
1965    #[cfg(any(test, feature = "test-support"))]
1966    pub fn is_parsing(&self, cx: &App) -> bool {
1967        self.as_singleton().unwrap().read(cx).is_parsing()
1968    }
1969
1970    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1971        let buffer_id = diff.read(cx).buffer_id;
1972        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
1973        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
1974    }
1975
1976    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
1977        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
1978    }
1979
1980    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
1981        self.expand_or_collapse_diff_hunks(ranges, true, cx);
1982    }
1983
1984    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
1985        self.expand_or_collapse_diff_hunks(ranges, false, cx);
1986    }
1987
1988    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
1989        self.snapshot.get_mut().all_diff_hunks_expanded = true;
1990        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
1991    }
1992
1993    pub fn all_diff_hunks_expanded(&self) -> bool {
1994        self.snapshot.borrow().all_diff_hunks_expanded
1995    }
1996
1997    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
1998        self.snapshot.get_mut().all_diff_hunks_expanded = false;
1999        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2000    }
2001
2002    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2003        self.read(cx)
2004            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2005            .nth(1)
2006            .is_some()
2007    }
2008
2009    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2010        let snapshot = self.read(cx);
2011        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2012        let offset_range = range.to_offset(&snapshot);
2013        cursor.seek(&offset_range.start, Bias::Left);
2014        while let Some(item) = cursor.item() {
2015            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2016                break;
2017            }
2018            if item.hunk_info().is_some() {
2019                return true;
2020            }
2021            cursor.next();
2022        }
2023        false
2024    }
2025
2026    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2027        let snapshot = self.read(cx);
2028        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2029        for range in ranges {
2030            let range = range.to_point(&snapshot);
2031            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2032            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2033            let start = start.saturating_sub(1);
2034            let end = snapshot.len().min(end + 1);
2035            cursor.seek(&start, Bias::Right);
2036            while let Some(item) = cursor.item() {
2037                if *cursor.start() >= end {
2038                    break;
2039                }
2040                if item.hunk_info().is_some() {
2041                    return true;
2042                }
2043                cursor.next();
2044            }
2045        }
2046        false
2047    }
2048
2049    pub fn expand_or_collapse_diff_hunks_inner(
2050        &mut self,
2051        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2052        expand: bool,
2053        cx: &mut Context<Self>,
2054    ) {
2055        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2056            return;
2057        }
2058        self.sync_mut(cx);
2059        let mut snapshot = self.snapshot.get_mut();
2060        let mut excerpt_edits = Vec::new();
2061        let mut last_hunk_row = None;
2062        for (range, end_excerpt_id) in ranges {
2063            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2064                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2065                    continue;
2066                }
2067                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2068                    continue;
2069                }
2070                let start = Anchor::in_buffer(
2071                    diff_hunk.excerpt_id,
2072                    diff_hunk.buffer_id,
2073                    diff_hunk.buffer_range.start,
2074                );
2075                let end = Anchor::in_buffer(
2076                    diff_hunk.excerpt_id,
2077                    diff_hunk.buffer_id,
2078                    diff_hunk.buffer_range.end,
2079                );
2080                let start = snapshot.excerpt_offset_for_anchor(&start);
2081                let end = snapshot.excerpt_offset_for_anchor(&end);
2082                last_hunk_row = Some(diff_hunk.row_range.start);
2083                excerpt_edits.push(text::Edit {
2084                    old: start..end,
2085                    new: start..end,
2086                });
2087            }
2088        }
2089
2090        let edits = Self::sync_diff_transforms(
2091            &mut snapshot,
2092            excerpt_edits,
2093            DiffChangeKind::ExpandOrCollapseHunks { expand },
2094        );
2095        if !edits.is_empty() {
2096            self.subscriptions.publish(edits);
2097        }
2098        cx.emit(Event::DiffHunksToggled);
2099        cx.emit(Event::Edited {
2100            edited_buffer: None,
2101        });
2102    }
2103
2104    pub fn expand_or_collapse_diff_hunks(
2105        &mut self,
2106        ranges: Vec<Range<Anchor>>,
2107        expand: bool,
2108        cx: &mut Context<Self>,
2109    ) {
2110        let snapshot = self.snapshot.borrow().clone();
2111        let ranges = ranges.iter().map(move |range| {
2112            let end_excerpt_id = range.end.excerpt_id;
2113            let range = range.to_point(&snapshot);
2114            let mut peek_end = range.end;
2115            if range.end.row < snapshot.max_row().0 {
2116                peek_end = Point::new(range.end.row + 1, 0);
2117            };
2118            (range.start..peek_end, end_excerpt_id)
2119        });
2120        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2121    }
2122
2123    pub fn resize_excerpt(
2124        &mut self,
2125        id: ExcerptId,
2126        range: Range<text::Anchor>,
2127        cx: &mut Context<Self>,
2128    ) {
2129        self.sync_mut(cx);
2130
2131        let mut snapshot = self.snapshot.get_mut();
2132        let locator = snapshot.excerpt_locator_for_id(id);
2133        let mut new_excerpts = SumTree::default();
2134        let mut cursor = snapshot
2135            .excerpts
2136            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2137        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2138
2139        let prefix = cursor.slice(&Some(locator), Bias::Left);
2140        new_excerpts.append(prefix, ());
2141
2142        let mut excerpt = cursor.item().unwrap().clone();
2143        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2144
2145        excerpt.range.context.start = range.start;
2146        excerpt.range.context.end = range.end;
2147        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2148
2149        excerpt.text_summary = excerpt
2150            .buffer
2151            .text_summary_for_range(excerpt.range.context.clone());
2152
2153        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2154        let old_start_offset = cursor.start().1;
2155        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2156        let edit = Edit {
2157            old: old_start_offset..old_start_offset + old_text_len,
2158            new: new_start_offset..new_start_offset + new_text_len,
2159        };
2160
2161        if let Some(last_edit) = edits.last_mut() {
2162            if last_edit.old.end == edit.old.start {
2163                last_edit.old.end = edit.old.end;
2164                last_edit.new.end = edit.new.end;
2165            } else {
2166                edits.push(edit);
2167            }
2168        } else {
2169            edits.push(edit);
2170        }
2171
2172        new_excerpts.push(excerpt, ());
2173
2174        cursor.next();
2175
2176        new_excerpts.append(cursor.suffix(), ());
2177
2178        drop(cursor);
2179        snapshot.excerpts = new_excerpts;
2180
2181        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2182        if !edits.is_empty() {
2183            self.subscriptions.publish(edits);
2184        }
2185        cx.emit(Event::Edited {
2186            edited_buffer: None,
2187        });
2188        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2189        cx.notify();
2190    }
2191
2192    pub fn expand_excerpts(
2193        &mut self,
2194        ids: impl IntoIterator<Item = ExcerptId>,
2195        line_count: u32,
2196        direction: ExpandExcerptDirection,
2197        cx: &mut Context<Self>,
2198    ) {
2199        if line_count == 0 {
2200            return;
2201        }
2202        self.sync_mut(cx);
2203        if !self.excerpts_by_path.is_empty() {
2204            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2205            return;
2206        }
2207        let mut snapshot = self.snapshot.get_mut();
2208
2209        let ids = ids.into_iter().collect::<Vec<_>>();
2210        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2211        let mut new_excerpts = SumTree::default();
2212        let mut cursor = snapshot
2213            .excerpts
2214            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2215        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2216
2217        for locator in &locators {
2218            let prefix = cursor.slice(&Some(locator), Bias::Left);
2219            new_excerpts.append(prefix, ());
2220
2221            let mut excerpt = cursor.item().unwrap().clone();
2222            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2223
2224            let up_line_count = if direction.should_expand_up() {
2225                line_count
2226            } else {
2227                0
2228            };
2229
2230            let start_row = excerpt
2231                .range
2232                .context
2233                .start
2234                .to_point(&excerpt.buffer)
2235                .row
2236                .saturating_sub(up_line_count);
2237            let start_point = Point::new(start_row, 0);
2238            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2239
2240            let down_line_count = if direction.should_expand_down() {
2241                line_count
2242            } else {
2243                0
2244            };
2245
2246            let mut end_point = excerpt.buffer.clip_point(
2247                excerpt.range.context.end.to_point(&excerpt.buffer)
2248                    + Point::new(down_line_count, 0),
2249                Bias::Left,
2250            );
2251            end_point.column = excerpt.buffer.line_len(end_point.row);
2252            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2253            excerpt.max_buffer_row = end_point.row;
2254
2255            excerpt.text_summary = excerpt
2256                .buffer
2257                .text_summary_for_range(excerpt.range.context.clone());
2258
2259            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2260            let old_start_offset = cursor.start().1;
2261            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2262            let edit = Edit {
2263                old: old_start_offset..old_start_offset + old_text_len,
2264                new: new_start_offset..new_start_offset + new_text_len,
2265            };
2266
2267            if let Some(last_edit) = edits.last_mut() {
2268                if last_edit.old.end == edit.old.start {
2269                    last_edit.old.end = edit.old.end;
2270                    last_edit.new.end = edit.new.end;
2271                } else {
2272                    edits.push(edit);
2273                }
2274            } else {
2275                edits.push(edit);
2276            }
2277
2278            new_excerpts.push(excerpt, ());
2279
2280            cursor.next();
2281        }
2282
2283        new_excerpts.append(cursor.suffix(), ());
2284
2285        drop(cursor);
2286        snapshot.excerpts = new_excerpts;
2287
2288        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2289        if !edits.is_empty() {
2290            self.subscriptions.publish(edits);
2291        }
2292        cx.emit(Event::Edited {
2293            edited_buffer: None,
2294        });
2295        cx.emit(Event::ExcerptsExpanded { ids });
2296        cx.notify();
2297    }
2298
2299    fn sync(&self, cx: &App) {
2300        let changed = self.buffer_changed_since_sync.replace(false);
2301        if !changed {
2302            return;
2303        }
2304        let edits = Self::sync_(
2305            &mut self.snapshot.borrow_mut(),
2306            &self.buffers,
2307            &self.diffs,
2308            cx,
2309        );
2310        if !edits.is_empty() {
2311            self.subscriptions.publish(edits);
2312        }
2313    }
2314
2315    fn sync_mut(&mut self, cx: &App) {
2316        let changed = self.buffer_changed_since_sync.replace(false);
2317        if !changed {
2318            return;
2319        }
2320        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2321
2322        if !edits.is_empty() {
2323            self.subscriptions.publish(edits);
2324        }
2325    }
2326
2327    fn sync_(
2328        snapshot: &mut MultiBufferSnapshot,
2329        buffers: &HashMap<BufferId, BufferState>,
2330        diffs: &HashMap<BufferId, DiffState>,
2331        cx: &App,
2332    ) -> Vec<Edit<usize>> {
2333        let MultiBufferSnapshot {
2334            excerpts,
2335            diffs: buffer_diff,
2336            diff_transforms: _,
2337            non_text_state_update_count,
2338            edit_count,
2339            is_dirty,
2340            has_deleted_file,
2341            has_conflict,
2342            singleton: _,
2343            excerpt_ids: _,
2344            replaced_excerpts: _,
2345            trailing_excerpt_update_count: _,
2346            all_diff_hunks_expanded: _,
2347            show_headers: _,
2348        } = snapshot;
2349        *is_dirty = false;
2350        *has_deleted_file = false;
2351        *has_conflict = false;
2352
2353        let mut excerpts_to_edit = Vec::new();
2354        let mut non_text_state_updated = false;
2355        let mut edited = false;
2356        for buffer_state in buffers.values() {
2357            let buffer = buffer_state.buffer.read(cx);
2358            let version = buffer.version();
2359            let non_text_state_update_count = buffer.non_text_state_update_count();
2360
2361            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2362            let buffer_non_text_state_updated =
2363                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2364            if buffer_edited || buffer_non_text_state_updated {
2365                *buffer_state.last_version.borrow_mut() = version;
2366                buffer_state
2367                    .last_non_text_state_update_count
2368                    .set(non_text_state_update_count);
2369                excerpts_to_edit.extend(
2370                    buffer_state
2371                        .excerpts
2372                        .iter()
2373                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2374                );
2375            }
2376
2377            edited |= buffer_edited;
2378            non_text_state_updated |= buffer_non_text_state_updated;
2379            *is_dirty |= buffer.is_dirty();
2380            *has_deleted_file |= buffer
2381                .file()
2382                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
2383            *has_conflict |= buffer.has_conflict();
2384        }
2385        if edited {
2386            *edit_count += 1;
2387        }
2388        if non_text_state_updated {
2389            *non_text_state_update_count += 1;
2390        }
2391
2392        for (id, diff) in diffs.iter() {
2393            if buffer_diff.get(id).is_none() {
2394                buffer_diff.insert(*id, diff.diff.read(cx).snapshot(cx));
2395            }
2396        }
2397
2398        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2399
2400        let mut edits = Vec::new();
2401        let mut new_excerpts = SumTree::default();
2402        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2403
2404        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2405            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2406            let old_excerpt = cursor.item().unwrap();
2407            let buffer = buffer.read(cx);
2408            let buffer_id = buffer.remote_id();
2409
2410            let mut new_excerpt;
2411            if buffer_edited {
2412                edits.extend(
2413                    buffer
2414                        .edits_since_in_range::<usize>(
2415                            old_excerpt.buffer.version(),
2416                            old_excerpt.range.context.clone(),
2417                        )
2418                        .map(|edit| {
2419                            let excerpt_old_start = cursor.start().1;
2420                            let excerpt_new_start =
2421                                ExcerptOffset::new(new_excerpts.summary().text.len);
2422                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2423                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2424                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2425                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2426                            Edit {
2427                                old: old_start..old_end,
2428                                new: new_start..new_end,
2429                            }
2430                        }),
2431                );
2432
2433                new_excerpt = Excerpt::new(
2434                    old_excerpt.id,
2435                    locator.clone(),
2436                    buffer_id,
2437                    buffer.snapshot(),
2438                    old_excerpt.range.clone(),
2439                    old_excerpt.has_trailing_newline,
2440                );
2441            } else {
2442                new_excerpt = old_excerpt.clone();
2443                new_excerpt.buffer = buffer.snapshot();
2444            }
2445
2446            new_excerpts.push(new_excerpt, ());
2447            cursor.next();
2448        }
2449        new_excerpts.append(cursor.suffix(), ());
2450
2451        drop(cursor);
2452        *excerpts = new_excerpts;
2453        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2454    }
2455
2456    fn sync_diff_transforms(
2457        snapshot: &mut MultiBufferSnapshot,
2458        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2459        change_kind: DiffChangeKind,
2460    ) -> Vec<Edit<usize>> {
2461        if excerpt_edits.is_empty() {
2462            return vec![];
2463        }
2464
2465        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2466        let mut old_diff_transforms = snapshot
2467            .diff_transforms
2468            .cursor::<Dimensions<ExcerptOffset, usize>>(());
2469        let mut new_diff_transforms = SumTree::default();
2470        let mut old_expanded_hunks = HashSet::default();
2471        let mut output_edits = Vec::new();
2472        let mut output_delta = 0_isize;
2473        let mut at_transform_boundary = true;
2474        let mut end_of_current_insert = None;
2475
2476        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2477        while let Some(edit) = excerpt_edits.next() {
2478            excerpts.seek_forward(&edit.new.start, Bias::Right);
2479            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2480                excerpts.prev();
2481            }
2482
2483            // Keep any transforms that are before the edit.
2484            if at_transform_boundary {
2485                at_transform_boundary = false;
2486                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2487                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2488                if let Some(transform) = old_diff_transforms.item()
2489                    && old_diff_transforms.end().0 == edit.old.start
2490                    && old_diff_transforms.start().0 < edit.old.start
2491                {
2492                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2493                    old_diff_transforms.next();
2494                }
2495            }
2496
2497            // Compute the start of the edit in output coordinates.
2498            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2499            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2500            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2501
2502            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2503                &edit,
2504                &mut excerpts,
2505                &mut old_diff_transforms,
2506                &mut new_diff_transforms,
2507                &mut end_of_current_insert,
2508                &mut old_expanded_hunks,
2509                snapshot,
2510                change_kind,
2511            );
2512
2513            // Compute the end of the edit in output coordinates.
2514            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2515            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2516            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2517            let edit_new_end =
2518                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2519            let output_edit = Edit {
2520                old: edit_old_start..edit_old_end,
2521                new: edit_new_start..edit_new_end,
2522            };
2523
2524            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2525            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2526            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2527                output_edits.push(output_edit);
2528            }
2529
2530            // If this is the last edit that intersects the current diff transform,
2531            // then recreate the content up to the end of this transform, to prepare
2532            // for reusing additional slices of the old transforms.
2533            if excerpt_edits
2534                .peek()
2535                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2536            {
2537                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2538                    && match old_diff_transforms.item() {
2539                        Some(DiffTransform::BufferContent {
2540                            inserted_hunk_info: Some(hunk),
2541                            ..
2542                        }) => excerpts.item().is_some_and(|excerpt| {
2543                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2544                        }),
2545                        _ => true,
2546                    };
2547
2548                let mut excerpt_offset = edit.new.end;
2549                if !keep_next_old_transform {
2550                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2551                    old_diff_transforms.next();
2552                }
2553
2554                old_expanded_hunks.clear();
2555                Self::push_buffer_content_transform(
2556                    snapshot,
2557                    &mut new_diff_transforms,
2558                    excerpt_offset,
2559                    end_of_current_insert,
2560                );
2561                at_transform_boundary = true;
2562            }
2563        }
2564
2565        // Keep any transforms that are after the last edit.
2566        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2567
2568        // Ensure there's always at least one buffer content transform.
2569        if new_diff_transforms.is_empty() {
2570            new_diff_transforms.push(
2571                DiffTransform::BufferContent {
2572                    summary: Default::default(),
2573                    inserted_hunk_info: None,
2574                },
2575                (),
2576            );
2577        }
2578
2579        drop(old_diff_transforms);
2580        drop(excerpts);
2581        snapshot.diff_transforms = new_diff_transforms;
2582        snapshot.edit_count += 1;
2583
2584        #[cfg(any(test, feature = "test-support"))]
2585        snapshot.check_invariants();
2586        output_edits
2587    }
2588
2589    fn recompute_diff_transforms_for_edit(
2590        edit: &Edit<TypedOffset<Excerpt>>,
2591        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2592        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
2593        new_diff_transforms: &mut SumTree<DiffTransform>,
2594        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2595        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2596        snapshot: &MultiBufferSnapshot,
2597        change_kind: DiffChangeKind,
2598    ) -> bool {
2599        log::trace!(
2600            "recomputing diff transform for edit {:?} => {:?}",
2601            edit.old.start.value..edit.old.end.value,
2602            edit.new.start.value..edit.new.end.value
2603        );
2604
2605        // Record which hunks were previously expanded.
2606        while let Some(item) = old_diff_transforms.item() {
2607            if let Some(hunk_info) = item.hunk_info() {
2608                log::trace!(
2609                    "previously expanded hunk at {}",
2610                    old_diff_transforms.start().0
2611                );
2612                old_expanded_hunks.insert(hunk_info);
2613            }
2614            if old_diff_transforms.end().0 > edit.old.end {
2615                break;
2616            }
2617            old_diff_transforms.next();
2618        }
2619
2620        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2621        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2622        if old_expanded_hunks.is_empty()
2623            && change_kind == DiffChangeKind::BufferEdited
2624            && !all_diff_hunks_expanded
2625        {
2626            return false;
2627        }
2628
2629        // Visit each excerpt that intersects the edit.
2630        let mut did_expand_hunks = false;
2631        while let Some(excerpt) = excerpts.item() {
2632            // Recompute the expanded hunks in the portion of the excerpt that
2633            // intersects the edit.
2634            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2635                let buffer = &excerpt.buffer;
2636                let excerpt_start = *excerpts.start();
2637                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2638                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2639                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2640                let edit_buffer_start =
2641                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2642                let edit_buffer_end =
2643                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2644                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2645                let edit_anchor_range =
2646                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2647
2648                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2649                    if hunk.is_created_file() && !all_diff_hunks_expanded {
2650                        continue;
2651                    }
2652
2653                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2654                    if hunk_buffer_range.start < excerpt_buffer_start {
2655                        log::trace!("skipping hunk that starts before excerpt");
2656                        continue;
2657                    }
2658
2659                    let hunk_info = DiffTransformHunkInfo {
2660                        excerpt_id: excerpt.id,
2661                        hunk_start_anchor: hunk.buffer_range.start,
2662                        hunk_secondary_status: hunk.secondary_status,
2663                    };
2664
2665                    let hunk_excerpt_start = excerpt_start
2666                        + ExcerptOffset::new(
2667                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2668                        );
2669                    let hunk_excerpt_end = excerpt_end.min(
2670                        excerpt_start
2671                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2672                    );
2673
2674                    Self::push_buffer_content_transform(
2675                        snapshot,
2676                        new_diff_transforms,
2677                        hunk_excerpt_start,
2678                        *end_of_current_insert,
2679                    );
2680
2681                    // For every existing hunk, determine if it was previously expanded
2682                    // and if it should currently be expanded.
2683                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2684                    let should_expand_hunk = match &change_kind {
2685                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2686                            was_previously_expanded || all_diff_hunks_expanded
2687                        }
2688                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2689                            let intersects = hunk_buffer_range.is_empty()
2690                                || hunk_buffer_range.end > edit_buffer_start;
2691                            if *expand {
2692                                intersects || was_previously_expanded || all_diff_hunks_expanded
2693                            } else {
2694                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
2695                            }
2696                        }
2697                        _ => was_previously_expanded || all_diff_hunks_expanded,
2698                    };
2699
2700                    if should_expand_hunk {
2701                        did_expand_hunks = true;
2702                        log::trace!(
2703                            "expanding hunk {:?}, excerpt:{:?}",
2704                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2705                            excerpt.id
2706                        );
2707
2708                        if !hunk.diff_base_byte_range.is_empty()
2709                            && hunk_buffer_range.start >= edit_buffer_start
2710                            && hunk_buffer_range.start <= excerpt_buffer_end
2711                        {
2712                            let base_text = diff.base_text();
2713                            let mut text_cursor =
2714                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2715                            let mut base_text_summary =
2716                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2717
2718                            let mut has_trailing_newline = false;
2719                            if base_text_summary.last_line_chars > 0 {
2720                                base_text_summary += TextSummary::newline();
2721                                has_trailing_newline = true;
2722                            }
2723
2724                            new_diff_transforms.push(
2725                                DiffTransform::DeletedHunk {
2726                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2727                                    summary: base_text_summary,
2728                                    buffer_id: excerpt.buffer_id,
2729                                    hunk_info,
2730                                    has_trailing_newline,
2731                                },
2732                                (),
2733                            );
2734                        }
2735
2736                        if !hunk_buffer_range.is_empty() {
2737                            *end_of_current_insert =
2738                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2739                        }
2740                    }
2741                }
2742            }
2743
2744            if excerpts.end() <= edit.new.end {
2745                excerpts.next();
2746            } else {
2747                break;
2748            }
2749        }
2750
2751        did_expand_hunks || !old_expanded_hunks.is_empty()
2752    }
2753
2754    fn append_diff_transforms(
2755        new_transforms: &mut SumTree<DiffTransform>,
2756        subtree: SumTree<DiffTransform>,
2757    ) {
2758        if let Some(DiffTransform::BufferContent {
2759            inserted_hunk_info,
2760            summary,
2761        }) = subtree.first()
2762            && Self::extend_last_buffer_content_transform(
2763                new_transforms,
2764                *inserted_hunk_info,
2765                *summary,
2766            )
2767        {
2768            let mut cursor = subtree.cursor::<()>(());
2769            cursor.next();
2770            cursor.next();
2771            new_transforms.append(cursor.suffix(), ());
2772            return;
2773        }
2774        new_transforms.append(subtree, ());
2775    }
2776
2777    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
2778        if let DiffTransform::BufferContent {
2779            inserted_hunk_info: inserted_hunk_anchor,
2780            summary,
2781        } = transform
2782            && Self::extend_last_buffer_content_transform(
2783                new_transforms,
2784                inserted_hunk_anchor,
2785                summary,
2786            )
2787        {
2788            return;
2789        }
2790        new_transforms.push(transform, ());
2791    }
2792
2793    fn push_buffer_content_transform(
2794        old_snapshot: &MultiBufferSnapshot,
2795        new_transforms: &mut SumTree<DiffTransform>,
2796        end_offset: ExcerptOffset,
2797        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2798    ) {
2799        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
2800            (end_offset.min(insertion_end_offset), Some(hunk_info))
2801        });
2802        let unchanged_region = [(end_offset, None)];
2803
2804        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
2805        {
2806            let start_offset = new_transforms.summary().excerpt_len();
2807            if end_offset <= start_offset {
2808                continue;
2809            }
2810            let summary_to_add = old_snapshot
2811                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
2812
2813            if !Self::extend_last_buffer_content_transform(
2814                new_transforms,
2815                inserted_hunk_info,
2816                summary_to_add,
2817            ) {
2818                new_transforms.push(
2819                    DiffTransform::BufferContent {
2820                        summary: summary_to_add,
2821                        inserted_hunk_info,
2822                    },
2823                    (),
2824                )
2825            }
2826        }
2827    }
2828
2829    fn extend_last_buffer_content_transform(
2830        new_transforms: &mut SumTree<DiffTransform>,
2831        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
2832        summary_to_add: TextSummary,
2833    ) -> bool {
2834        let mut did_extend = false;
2835        new_transforms.update_last(
2836            |last_transform| {
2837                if let DiffTransform::BufferContent {
2838                    summary,
2839                    inserted_hunk_info: inserted_hunk_anchor,
2840                } = last_transform
2841                    && *inserted_hunk_anchor == new_inserted_hunk_info
2842                {
2843                    *summary += summary_to_add;
2844                    did_extend = true;
2845                }
2846            },
2847            (),
2848        );
2849        did_extend
2850    }
2851}
2852
2853fn build_excerpt_ranges(
2854    ranges: impl IntoIterator<Item = Range<Point>>,
2855    context_line_count: u32,
2856    buffer_snapshot: &BufferSnapshot,
2857) -> Vec<ExcerptRange<Point>> {
2858    ranges
2859        .into_iter()
2860        .map(|range| {
2861            let start_row = range.start.row.saturating_sub(context_line_count);
2862            let start = Point::new(start_row, 0);
2863            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
2864            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
2865            ExcerptRange {
2866                context: start..end,
2867                primary: range,
2868            }
2869        })
2870        .collect()
2871}
2872
2873#[cfg(any(test, feature = "test-support"))]
2874impl MultiBuffer {
2875    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
2876        let buffer = cx.new(|cx| Buffer::local(text, cx));
2877        cx.new(|cx| Self::singleton(buffer, cx))
2878    }
2879
2880    pub fn build_multi<const COUNT: usize>(
2881        excerpts: [(&str, Vec<Range<Point>>); COUNT],
2882        cx: &mut gpui::App,
2883    ) -> Entity<Self> {
2884        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
2885        for (text, ranges) in excerpts {
2886            let buffer = cx.new(|cx| Buffer::local(text, cx));
2887            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
2888            multi.update(cx, |multi, cx| {
2889                multi.push_excerpts(buffer, excerpt_ranges, cx)
2890            });
2891        }
2892
2893        multi
2894    }
2895
2896    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
2897        cx.new(|cx| Self::singleton(buffer, cx))
2898    }
2899
2900    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
2901        cx.new(|cx| {
2902            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
2903            let mutation_count = rng.random_range(1..=5);
2904            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
2905            multibuffer
2906        })
2907    }
2908
2909    pub fn randomly_edit(
2910        &mut self,
2911        rng: &mut impl rand::Rng,
2912        edit_count: usize,
2913        cx: &mut Context<Self>,
2914    ) {
2915        use util::RandomCharIter;
2916
2917        let snapshot = self.read(cx);
2918        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
2919        let mut last_end = None;
2920        for _ in 0..edit_count {
2921            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
2922                break;
2923            }
2924
2925            let new_start = last_end.map_or(0, |last_end| last_end + 1);
2926            let end =
2927                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
2928            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
2929            last_end = Some(end);
2930
2931            let mut range = start..end;
2932            if rng.random_bool(0.2) {
2933                mem::swap(&mut range.start, &mut range.end);
2934            }
2935
2936            let new_text_len = rng.random_range(0..10);
2937            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
2938
2939            edits.push((range, new_text.into()));
2940        }
2941        log::info!("mutating multi-buffer with {:?}", edits);
2942        drop(snapshot);
2943
2944        self.edit(edits, None, cx);
2945    }
2946
2947    pub fn randomly_edit_excerpts(
2948        &mut self,
2949        rng: &mut impl rand::Rng,
2950        mutation_count: usize,
2951        cx: &mut Context<Self>,
2952    ) {
2953        use rand::prelude::*;
2954        use std::env;
2955        use util::RandomCharIter;
2956
2957        let max_excerpts = env::var("MAX_EXCERPTS")
2958            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
2959            .unwrap_or(5);
2960
2961        let mut buffers = Vec::new();
2962        for _ in 0..mutation_count {
2963            if rng.random_bool(0.05) {
2964                log::info!("Clearing multi-buffer");
2965                self.clear(cx);
2966                continue;
2967            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
2968                let ids = self.excerpt_ids();
2969                let mut excerpts = HashSet::default();
2970                for _ in 0..rng.random_range(0..ids.len()) {
2971                    excerpts.extend(ids.choose(rng).copied());
2972                }
2973
2974                let line_count = rng.random_range(0..5);
2975
2976                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
2977
2978                self.expand_excerpts(
2979                    excerpts.iter().cloned(),
2980                    line_count,
2981                    ExpandExcerptDirection::UpAndDown,
2982                    cx,
2983                );
2984                continue;
2985            }
2986
2987            let excerpt_ids = self.excerpt_ids();
2988            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
2989                let buffer_handle = if rng.random() || self.buffers.is_empty() {
2990                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
2991                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
2992                    let buffer = buffers.last().unwrap().read(cx);
2993                    log::info!(
2994                        "Creating new buffer {} with text: {:?}",
2995                        buffer.remote_id(),
2996                        buffer.text()
2997                    );
2998                    buffers.last().unwrap().clone()
2999                } else {
3000                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3001                };
3002
3003                let buffer = buffer_handle.read(cx);
3004                let buffer_text = buffer.text();
3005                let ranges = (0..rng.random_range(0..5))
3006                    .map(|_| {
3007                        let end_ix =
3008                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3009                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3010                        ExcerptRange::new(start_ix..end_ix)
3011                    })
3012                    .collect::<Vec<_>>();
3013                log::info!(
3014                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3015                    buffer_handle.read(cx).remote_id(),
3016                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3017                    ranges
3018                        .iter()
3019                        .map(|r| &buffer_text[r.context.clone()])
3020                        .collect::<Vec<_>>()
3021                );
3022
3023                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3024                log::info!("Inserted with ids: {:?}", excerpt_id);
3025            } else {
3026                let remove_count = rng.random_range(1..=excerpt_ids.len());
3027                let mut excerpts_to_remove = excerpt_ids
3028                    .choose_multiple(rng, remove_count)
3029                    .cloned()
3030                    .collect::<Vec<_>>();
3031                let snapshot = self.snapshot.borrow();
3032                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3033                drop(snapshot);
3034                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3035                self.remove_excerpts(excerpts_to_remove, cx);
3036            }
3037        }
3038    }
3039
3040    pub fn randomly_mutate(
3041        &mut self,
3042        rng: &mut impl rand::Rng,
3043        mutation_count: usize,
3044        cx: &mut Context<Self>,
3045    ) {
3046        use rand::prelude::*;
3047
3048        if rng.random_bool(0.7) || self.singleton {
3049            let buffer = self
3050                .buffers
3051                .values()
3052                .choose(rng)
3053                .map(|state| state.buffer.clone());
3054
3055            if let Some(buffer) = buffer {
3056                buffer.update(cx, |buffer, cx| {
3057                    if rng.random() {
3058                        buffer.randomly_edit(rng, mutation_count, cx);
3059                    } else {
3060                        buffer.randomly_undo_redo(rng, cx);
3061                    }
3062                });
3063            } else {
3064                self.randomly_edit(rng, mutation_count, cx);
3065            }
3066        } else {
3067            self.randomly_edit_excerpts(rng, mutation_count, cx);
3068        }
3069
3070        self.check_invariants(cx);
3071    }
3072
3073    fn check_invariants(&self, cx: &App) {
3074        self.read(cx).check_invariants();
3075    }
3076}
3077
3078impl EventEmitter<Event> for MultiBuffer {}
3079
3080impl MultiBufferSnapshot {
3081    pub fn text(&self) -> String {
3082        self.chunks(0..self.len(), false)
3083            .map(|chunk| chunk.text)
3084            .collect()
3085    }
3086
3087    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3088        self.reversed_chunks_in_range(0..position.to_offset(self))
3089            .flat_map(|c| c.chars().rev())
3090    }
3091
3092    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3093        let mut cursor = self.cursor::<usize>();
3094        cursor.seek(&range.end);
3095        let current_chunks = cursor.region().as_ref().map(|region| {
3096            let start_overshoot = range.start.saturating_sub(region.range.start);
3097            let end_overshoot = range.end - region.range.start;
3098            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3099            let start = region.buffer_range.start + start_overshoot;
3100            region.buffer.reversed_chunks_in_range(start..end)
3101        });
3102        ReversedMultiBufferChunks {
3103            cursor,
3104            current_chunks,
3105            start: range.start,
3106            offset: range.end,
3107        }
3108    }
3109
3110    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3111        let offset = position.to_offset(self);
3112        self.text_for_range(offset..self.len())
3113            .flat_map(|chunk| chunk.chars())
3114    }
3115
3116    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3117        self.chunks(range, false).map(|chunk| chunk.text)
3118    }
3119
3120    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3121        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3122            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3123    }
3124
3125    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3126    where
3127        T: ToOffset,
3128    {
3129        let position = position.to_offset(self);
3130        position == self.clip_offset(position, Bias::Left)
3131            && self
3132                .bytes_in_range(position..self.len())
3133                .flatten()
3134                .copied()
3135                .take(needle.len())
3136                .eq(needle.bytes())
3137    }
3138
3139    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3140        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3141    }
3142
3143    pub fn diff_hunks_in_range<T: ToPoint>(
3144        &self,
3145        range: Range<T>,
3146    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3147        let query_range = range.start.to_point(self)..range.end.to_point(self);
3148        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3149            let diff = self.diffs.get(&buffer.remote_id())?;
3150            let buffer_start = buffer.anchor_before(buffer_range.start);
3151            let buffer_end = buffer.anchor_after(buffer_range.end);
3152            Some(
3153                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3154                    .filter_map(|hunk| {
3155                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3156                            return None;
3157                        }
3158                        Some((hunk.range.clone(), hunk))
3159                    }),
3160            )
3161        })
3162        .filter_map(move |(range, hunk, excerpt)| {
3163            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3164            {
3165                return None;
3166            }
3167            let end_row = if range.end.column == 0 {
3168                range.end.row
3169            } else {
3170                range.end.row + 1
3171            };
3172            Some(MultiBufferDiffHunk {
3173                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3174                buffer_id: excerpt.buffer_id,
3175                excerpt_id: excerpt.id,
3176                buffer_range: hunk.buffer_range.clone(),
3177                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3178                secondary_status: hunk.secondary_status,
3179            })
3180        })
3181    }
3182
3183    pub fn excerpt_ids_for_range<T: ToOffset>(
3184        &self,
3185        range: Range<T>,
3186    ) -> impl Iterator<Item = ExcerptId> + '_ {
3187        let range = range.start.to_offset(self)..range.end.to_offset(self);
3188        let mut cursor = self.cursor::<usize>();
3189        cursor.seek(&range.start);
3190        std::iter::from_fn(move || {
3191            let region = cursor.region()?;
3192            if region.range.start >= range.end {
3193                return None;
3194            }
3195            cursor.next_excerpt();
3196            Some(region.excerpt.id)
3197        })
3198    }
3199
3200    pub fn buffer_ids_for_range<T: ToOffset>(
3201        &self,
3202        range: Range<T>,
3203    ) -> impl Iterator<Item = BufferId> + '_ {
3204        let range = range.start.to_offset(self)..range.end.to_offset(self);
3205        let mut cursor = self.cursor::<usize>();
3206        cursor.seek(&range.start);
3207        std::iter::from_fn(move || {
3208            let region = cursor.region()?;
3209            if region.range.start > range.end
3210                || region.range.start == range.end && region.range.start > range.start
3211            {
3212                return None;
3213            }
3214            cursor.next_excerpt();
3215            Some(region.excerpt.buffer_id)
3216        })
3217    }
3218
3219    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3220        &self,
3221        ranges: impl Iterator<Item = Range<T>>,
3222    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3223        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3224    }
3225
3226    pub fn range_to_buffer_ranges<T: ToOffset>(
3227        &self,
3228        range: Range<T>,
3229    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3230        let start = range.start.to_offset(self);
3231        let end = range.end.to_offset(self);
3232
3233        let mut cursor = self.cursor::<usize>();
3234        cursor.seek(&start);
3235
3236        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3237        while let Some(region) = cursor.region() {
3238            if region.range.start > end {
3239                break;
3240            }
3241            if region.is_main_buffer {
3242                let start_overshoot = start.saturating_sub(region.range.start);
3243                let end_overshoot = end.saturating_sub(region.range.start);
3244                let start = region
3245                    .buffer_range
3246                    .end
3247                    .min(region.buffer_range.start + start_overshoot);
3248                let end = region
3249                    .buffer_range
3250                    .end
3251                    .min(region.buffer_range.start + end_overshoot);
3252                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3253                    *excerpt_id == region.excerpt.id && prev_range.end == start
3254                }) {
3255                    prev.1.end = end;
3256                } else {
3257                    result.push((region.buffer, start..end, region.excerpt.id));
3258                }
3259            }
3260            cursor.next();
3261        }
3262        result
3263    }
3264
3265    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3266        &self,
3267        range: Range<T>,
3268    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3269        let start = range.start.to_offset(self);
3270        let end = range.end.to_offset(self);
3271
3272        let mut cursor = self.cursor::<usize>();
3273        cursor.seek(&start);
3274
3275        std::iter::from_fn(move || {
3276            let region = cursor.region()?;
3277            if region.range.start > end {
3278                return None;
3279            }
3280            let start_overshoot = start.saturating_sub(region.range.start);
3281            let end_overshoot = end.saturating_sub(region.range.start);
3282            let start = region
3283                .buffer_range
3284                .end
3285                .min(region.buffer_range.start + start_overshoot);
3286            let end = region
3287                .buffer_range
3288                .end
3289                .min(region.buffer_range.start + end_overshoot);
3290
3291            let region_excerpt_id = region.excerpt.id;
3292            let deleted_hunk_anchor = if region.is_main_buffer {
3293                None
3294            } else {
3295                Some(self.anchor_before(region.range.start))
3296            };
3297            let result = (
3298                region.buffer,
3299                start..end,
3300                region_excerpt_id,
3301                deleted_hunk_anchor,
3302            );
3303            cursor.next();
3304            Some(result)
3305        })
3306    }
3307
3308    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3309    /// coordinates.
3310    ///
3311    /// The given callback will be called for every excerpt intersecting the given range. It will
3312    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3313    /// The callback should return an iterator of metadata items from that buffer, each paired
3314    /// with a buffer range.
3315    ///
3316    /// The returned iterator yields each of these metadata items, paired with its range in
3317    /// multi-buffer coordinates.
3318    fn lift_buffer_metadata<'a, D, M, I>(
3319        &'a self,
3320        query_range: Range<D>,
3321        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3322    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3323    where
3324        I: Iterator<Item = (Range<D>, M)> + 'a,
3325        D: TextDimension + Ord + Sub<D, Output = D>,
3326    {
3327        let max_position = D::from_text_summary(&self.text_summary());
3328        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3329        let mut cursor = self.cursor::<D>();
3330
3331        // Find the excerpt and buffer offset where the given range ends.
3332        cursor.seek(&query_range.end);
3333        let mut range_end = None;
3334        while let Some(region) = cursor.region() {
3335            if region.is_main_buffer {
3336                let mut buffer_end = region.buffer_range.start;
3337                let overshoot = if query_range.end > region.range.start {
3338                    query_range.end - region.range.start
3339                } else {
3340                    D::default()
3341                };
3342                buffer_end.add_assign(&overshoot);
3343                range_end = Some((region.excerpt.id, buffer_end));
3344                break;
3345            }
3346            cursor.next();
3347        }
3348
3349        cursor.seek(&query_range.start);
3350
3351        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3352            && region.range.start > D::zero(())
3353        {
3354            cursor.prev()
3355        }
3356
3357        iter::from_fn(move || {
3358            loop {
3359                let excerpt = cursor.excerpt()?;
3360
3361                // If we have already retrieved metadata for this excerpt, continue to use it.
3362                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3363                    .as_mut()
3364                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3365                {
3366                    Some(metadata)
3367                }
3368                // Otherwise, compute the intersection of the input range with the excerpt's range,
3369                // and retrieve the metadata for the resulting range.
3370                else {
3371                    let region = cursor.region()?;
3372                    let mut buffer_start;
3373                    if region.is_main_buffer {
3374                        buffer_start = region.buffer_range.start;
3375                        if query_range.start > region.range.start {
3376                            let overshoot = query_range.start - region.range.start;
3377                            buffer_start.add_assign(&overshoot);
3378                        }
3379                        buffer_start = buffer_start.min(region.buffer_range.end);
3380                    } else {
3381                        buffer_start = cursor.main_buffer_position()?;
3382                    };
3383                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3384                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
3385                        && excerpt.id == end_excerpt_id
3386                    {
3387                        buffer_end = buffer_end.min(end_buffer_offset);
3388                    }
3389
3390                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
3391                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
3392                    })
3393                };
3394
3395                // Visit each metadata item.
3396                if let Some((metadata_buffer_range, metadata)) =
3397                    metadata_iter.and_then(Iterator::next)
3398                {
3399                    // Find the multibuffer regions that contain the start and end of
3400                    // the metadata item's range.
3401                    if metadata_buffer_range.start > D::default() {
3402                        while let Some(region) = cursor.region() {
3403                            if region.is_main_buffer
3404                                && (region.buffer_range.end >= metadata_buffer_range.start
3405                                    || cursor.is_at_end_of_excerpt())
3406                            {
3407                                break;
3408                            }
3409                            cursor.next();
3410                        }
3411                    }
3412                    let start_region = cursor.region()?;
3413                    while let Some(region) = cursor.region() {
3414                        if region.is_main_buffer
3415                            && (region.buffer_range.end > metadata_buffer_range.end
3416                                || cursor.is_at_end_of_excerpt())
3417                        {
3418                            break;
3419                        }
3420                        cursor.next();
3421                    }
3422                    let end_region = cursor.region();
3423
3424                    // Convert the metadata item's range into multibuffer coordinates.
3425                    let mut start_position = start_region.range.start;
3426                    let region_buffer_start = start_region.buffer_range.start;
3427                    if start_region.is_main_buffer
3428                        && metadata_buffer_range.start > region_buffer_start
3429                    {
3430                        start_position
3431                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
3432                        start_position = start_position.min(start_region.range.end);
3433                    }
3434
3435                    let mut end_position = max_position;
3436                    if let Some(end_region) = &end_region {
3437                        end_position = end_region.range.start;
3438                        debug_assert!(end_region.is_main_buffer);
3439                        let region_buffer_start = end_region.buffer_range.start;
3440                        if metadata_buffer_range.end > region_buffer_start {
3441                            end_position
3442                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
3443                        }
3444                        end_position = end_position.min(end_region.range.end);
3445                    }
3446
3447                    if start_position <= query_range.end && end_position >= query_range.start {
3448                        return Some((start_position..end_position, metadata, excerpt));
3449                    }
3450                }
3451                // When there are no more metadata items for this excerpt, move to the next excerpt.
3452                else {
3453                    current_excerpt_metadata.take();
3454                    if let Some((end_excerpt_id, _)) = range_end
3455                        && excerpt.id == end_excerpt_id
3456                    {
3457                        return None;
3458                    }
3459                    cursor.next_excerpt();
3460                }
3461            }
3462        })
3463    }
3464
3465    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3466        let offset = position.to_offset(self);
3467
3468        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3469        cursor.seek(&DimensionPair {
3470            key: offset,
3471            value: None,
3472        });
3473        cursor.seek_to_start_of_current_excerpt();
3474        let excerpt = cursor.excerpt()?;
3475
3476        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3477        let current_position = self
3478            .anchor_before(offset)
3479            .text_anchor
3480            .to_offset(&excerpt.buffer);
3481        let excerpt_end = excerpt
3482            .buffer
3483            .anchor_before(excerpt_end.min(current_position));
3484
3485        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3486            for hunk in diff.hunks_intersecting_range_rev(
3487                excerpt.range.context.start..excerpt_end,
3488                &excerpt.buffer,
3489            ) {
3490                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3491                if hunk_end >= current_position {
3492                    continue;
3493                }
3494                let start =
3495                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3496                        .to_point(self);
3497                return Some(MultiBufferRow(start.row));
3498            }
3499        }
3500
3501        loop {
3502            cursor.prev_excerpt();
3503            let excerpt = cursor.excerpt()?;
3504
3505            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3506                continue;
3507            };
3508            let mut hunks =
3509                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3510            let Some(hunk) = hunks.next() else {
3511                continue;
3512            };
3513            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3514                .to_point(self);
3515            return Some(MultiBufferRow(start.row));
3516        }
3517    }
3518
3519    pub fn has_diff_hunks(&self) -> bool {
3520        self.diffs.values().any(|diff| !diff.is_empty())
3521    }
3522
3523    pub fn is_inside_word<T: ToOffset>(
3524        &self,
3525        position: T,
3526        scope_context: Option<CharScopeContext>,
3527    ) -> bool {
3528        let position = position.to_offset(self);
3529        let classifier = self
3530            .char_classifier_at(position)
3531            .scope_context(scope_context);
3532        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
3533        let prev_char_kind = self
3534            .reversed_chars_at(position)
3535            .next()
3536            .map(|c| classifier.kind(c));
3537        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
3538    }
3539
3540    pub fn surrounding_word<T: ToOffset>(
3541        &self,
3542        start: T,
3543        scope_context: Option<CharScopeContext>,
3544    ) -> (Range<usize>, Option<CharKind>) {
3545        let mut start = start.to_offset(self);
3546        let mut end = start;
3547        let mut next_chars = self.chars_at(start).peekable();
3548        let mut prev_chars = self.reversed_chars_at(start).peekable();
3549
3550        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3551
3552        let word_kind = cmp::max(
3553            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3554            next_chars.peek().copied().map(|c| classifier.kind(c)),
3555        );
3556
3557        for ch in prev_chars {
3558            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3559                start -= ch.len_utf8();
3560            } else {
3561                break;
3562            }
3563        }
3564
3565        for ch in next_chars {
3566            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3567                end += ch.len_utf8();
3568            } else {
3569                break;
3570            }
3571        }
3572
3573        (start..end, word_kind)
3574    }
3575
3576    pub fn char_kind_before<T: ToOffset>(
3577        &self,
3578        start: T,
3579        scope_context: Option<CharScopeContext>,
3580    ) -> Option<CharKind> {
3581        let start = start.to_offset(self);
3582        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3583        self.reversed_chars_at(start)
3584            .next()
3585            .map(|ch| classifier.kind(ch))
3586    }
3587
3588    pub fn is_singleton(&self) -> bool {
3589        self.singleton
3590    }
3591
3592    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3593        if self.singleton {
3594            self.excerpts
3595                .iter()
3596                .next()
3597                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3598        } else {
3599            None
3600        }
3601    }
3602
3603    pub fn len(&self) -> usize {
3604        self.diff_transforms.summary().output.len
3605    }
3606
3607    pub fn is_empty(&self) -> bool {
3608        self.excerpts.summary().text.len == 0
3609    }
3610
3611    pub fn widest_line_number(&self) -> u32 {
3612        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
3613        self.excerpts.summary().widest_line_number + 1
3614    }
3615
3616    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
3617        let range = range.start.to_offset(self)..range.end.to_offset(self);
3618        let mut excerpts = self.cursor::<usize>();
3619        excerpts.seek(&range.start);
3620
3621        let mut chunk;
3622        let mut has_trailing_newline;
3623        let excerpt_bytes;
3624        if let Some(region) = excerpts.region() {
3625            let mut bytes = region.buffer.bytes_in_range(
3626                region.buffer_range.start + range.start - region.range.start
3627                    ..(region.buffer_range.start + range.end - region.range.start)
3628                        .min(region.buffer_range.end),
3629            );
3630            chunk = bytes.next().unwrap_or(&[][..]);
3631            excerpt_bytes = Some(bytes);
3632            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3633            if chunk.is_empty() && has_trailing_newline {
3634                chunk = b"\n";
3635                has_trailing_newline = false;
3636            }
3637        } else {
3638            chunk = &[][..];
3639            excerpt_bytes = None;
3640            has_trailing_newline = false;
3641        };
3642
3643        MultiBufferBytes {
3644            range,
3645            cursor: excerpts,
3646            excerpt_bytes,
3647            has_trailing_newline,
3648            chunk,
3649        }
3650    }
3651
3652    pub fn reversed_bytes_in_range<T: ToOffset>(
3653        &self,
3654        range: Range<T>,
3655    ) -> ReversedMultiBufferBytes<'_> {
3656        let range = range.start.to_offset(self)..range.end.to_offset(self);
3657        let mut chunks = self.reversed_chunks_in_range(range.clone());
3658        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3659        ReversedMultiBufferBytes {
3660            range,
3661            chunks,
3662            chunk,
3663        }
3664    }
3665
3666    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
3667        let mut cursor = self.cursor::<Point>();
3668        cursor.seek(&Point::new(start_row.0, 0));
3669        let mut result = MultiBufferRows {
3670            point: Point::new(0, 0),
3671            is_empty: self.excerpts.is_empty(),
3672            is_singleton: self.is_singleton(),
3673            cursor,
3674        };
3675        result.seek(start_row);
3676        result
3677    }
3678
3679    pub fn chunks<T: ToOffset>(
3680        &self,
3681        range: Range<T>,
3682        language_aware: bool,
3683    ) -> MultiBufferChunks<'_> {
3684        let mut chunks = MultiBufferChunks {
3685            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3686            range: 0..0,
3687            excerpts: self.excerpts.cursor(()),
3688            diff_transforms: self.diff_transforms.cursor(()),
3689            diffs: &self.diffs,
3690            diff_base_chunks: None,
3691            excerpt_chunks: None,
3692            buffer_chunk: None,
3693            language_aware,
3694        };
3695        let range = range.start.to_offset(self)..range.end.to_offset(self);
3696        chunks.seek(range);
3697        chunks
3698    }
3699
3700    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3701        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3702    }
3703
3704    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3705        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3706    }
3707
3708    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3709        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3710    }
3711
3712    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3713        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3714            buffer.clip_point_utf16(Unclipped(point), bias)
3715        })
3716    }
3717
3718    pub fn offset_to_point(&self, offset: usize) -> Point {
3719        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3720    }
3721
3722    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3723        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3724    }
3725
3726    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3727        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3728    }
3729
3730    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
3731        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
3732    }
3733
3734    pub fn point_to_offset(&self, point: Point) -> usize {
3735        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3736    }
3737
3738    pub fn point_to_offset_utf16(&self, point: Point) -> OffsetUtf16 {
3739        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
3740    }
3741
3742    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3743        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3744    }
3745
3746    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3747        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3748    }
3749
3750    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3751        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3752    }
3753
3754    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> OffsetUtf16 {
3755        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
3756    }
3757
3758    fn clip_dimension<D>(
3759        &self,
3760        position: D,
3761        bias: Bias,
3762        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
3763    ) -> D
3764    where
3765        D: TextDimension + Ord + Sub<D, Output = D>,
3766    {
3767        let mut cursor = self.cursor();
3768        cursor.seek(&position);
3769        if let Some(region) = cursor.region() {
3770            if position >= region.range.end {
3771                return region.range.end;
3772            }
3773            let overshoot = position - region.range.start;
3774            let mut buffer_position = region.buffer_range.start;
3775            buffer_position.add_assign(&overshoot);
3776            let clipped_buffer_position =
3777                clip_buffer_position(region.buffer, buffer_position, bias);
3778            let mut position = region.range.start;
3779            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
3780            position
3781        } else {
3782            D::from_text_summary(&self.text_summary())
3783        }
3784    }
3785
3786    fn convert_dimension<D1, D2>(
3787        &self,
3788        key: D1,
3789        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
3790    ) -> D2
3791    where
3792        D1: TextDimension + Ord + Sub<D1, Output = D1>,
3793        D2: TextDimension + Ord + Sub<D2, Output = D2>,
3794    {
3795        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
3796        cursor.seek(&DimensionPair { key, value: None });
3797        if let Some(region) = cursor.region() {
3798            if key >= region.range.end.key {
3799                return region.range.end.value.unwrap();
3800            }
3801            let start_key = region.range.start.key;
3802            let start_value = region.range.start.value.unwrap();
3803            let buffer_start_key = region.buffer_range.start.key;
3804            let buffer_start_value = region.buffer_range.start.value.unwrap();
3805            let mut buffer_key = buffer_start_key;
3806            buffer_key.add_assign(&(key - start_key));
3807            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
3808            let mut result = start_value;
3809            result.add_assign(&(buffer_value - buffer_start_value));
3810            result
3811        } else {
3812            D2::from_text_summary(&self.text_summary())
3813        }
3814    }
3815
3816    pub fn point_to_buffer_offset<T: ToOffset>(
3817        &self,
3818        point: T,
3819    ) -> Option<(&BufferSnapshot, usize)> {
3820        let offset = point.to_offset(self);
3821        let mut cursor = self.cursor::<usize>();
3822        cursor.seek(&offset);
3823        let region = cursor.region()?;
3824        let overshoot = offset - region.range.start;
3825        let buffer_offset = region.buffer_range.start + overshoot;
3826        if buffer_offset == region.buffer.len() + 1
3827            && region.has_trailing_newline
3828            && !region.is_main_buffer
3829        {
3830            let main_buffer_position = cursor.main_buffer_position()?;
3831            let buffer_snapshot = &cursor.excerpt()?.buffer;
3832            // remove this assert once we figure out the cause of the panics for #40453
3833            buffer_snapshot
3834                .text
3835                .as_rope()
3836                .assert_char_boundary(main_buffer_position);
3837            return Some((buffer_snapshot, main_buffer_position));
3838        } else if buffer_offset > region.buffer.len() {
3839            return None;
3840        }
3841        // remove this assert once we figure out the cause of the panics for #40453
3842        region
3843            .buffer
3844            .text
3845            .as_rope()
3846            .assert_char_boundary(buffer_offset);
3847        Some((region.buffer, buffer_offset))
3848    }
3849
3850    pub fn point_to_buffer_point(
3851        &self,
3852        point: Point,
3853    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
3854        let mut cursor = self.cursor::<Point>();
3855        cursor.seek(&point);
3856        let region = cursor.region()?;
3857        let overshoot = point - region.range.start;
3858        let buffer_point = region.buffer_range.start + overshoot;
3859        let excerpt = cursor.excerpt()?;
3860        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
3861            && region.has_trailing_newline
3862            && !region.is_main_buffer
3863        {
3864            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
3865        } else if buffer_point > region.buffer.max_point() {
3866            return None;
3867        }
3868        Some((region.buffer, buffer_point, excerpt.id))
3869    }
3870
3871    pub fn suggested_indents(
3872        &self,
3873        rows: impl IntoIterator<Item = u32>,
3874        cx: &App,
3875    ) -> BTreeMap<MultiBufferRow, IndentSize> {
3876        let mut result = BTreeMap::new();
3877
3878        let mut rows_for_excerpt = Vec::new();
3879        let mut cursor = self.cursor::<Point>();
3880        let mut rows = rows.into_iter().peekable();
3881        let mut prev_row = u32::MAX;
3882        let mut prev_language_indent_size = IndentSize::default();
3883
3884        while let Some(row) = rows.next() {
3885            cursor.seek(&Point::new(row, 0));
3886            let Some(region) = cursor.region() else {
3887                continue;
3888            };
3889
3890            // Retrieve the language and indent size once for each disjoint region being indented.
3891            let single_indent_size = if row.saturating_sub(1) == prev_row {
3892                prev_language_indent_size
3893            } else {
3894                region
3895                    .buffer
3896                    .language_indent_size_at(Point::new(row, 0), cx)
3897            };
3898            prev_language_indent_size = single_indent_size;
3899            prev_row = row;
3900
3901            let start_buffer_row = region.buffer_range.start.row;
3902            let start_multibuffer_row = region.range.start.row;
3903            let end_multibuffer_row = region.range.end.row;
3904
3905            rows_for_excerpt.push(row);
3906            while let Some(next_row) = rows.peek().copied() {
3907                if end_multibuffer_row > next_row {
3908                    rows_for_excerpt.push(next_row);
3909                    rows.next();
3910                } else {
3911                    break;
3912                }
3913            }
3914
3915            let buffer_rows = rows_for_excerpt
3916                .drain(..)
3917                .map(|row| start_buffer_row + row - start_multibuffer_row);
3918            let buffer_indents = region
3919                .buffer
3920                .suggested_indents(buffer_rows, single_indent_size);
3921            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
3922                (
3923                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
3924                    indent,
3925                )
3926            });
3927            result.extend(multibuffer_indents);
3928        }
3929
3930        result
3931    }
3932
3933    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
3934        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3935            let mut size = buffer.indent_size_for_line(range.start.row);
3936            size.len = size
3937                .len
3938                .min(range.end.column)
3939                .saturating_sub(range.start.column);
3940            size
3941        } else {
3942            IndentSize::spaces(0)
3943        }
3944    }
3945
3946    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
3947        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3948            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
3949        } else {
3950            LineIndent::spaces(0)
3951        }
3952    }
3953
3954    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
3955        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
3956
3957        if self.language_settings(cx).extend_comment_on_newline
3958            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
3959        {
3960            let delimiters = language_scope.line_comment_prefixes();
3961            for delimiter in delimiters {
3962                if *self
3963                    .chars_at(Point::new(row.0, indent.len() as u32))
3964                    .take(delimiter.chars().count())
3965                    .collect::<String>()
3966                    .as_str()
3967                    == **delimiter
3968                {
3969                    indent.push_str(delimiter);
3970                    break;
3971                }
3972            }
3973        }
3974
3975        indent
3976    }
3977
3978    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
3979    where
3980        T: ToOffset,
3981    {
3982        for char in self.reversed_chars_at(position) {
3983            if !char.is_whitespace() {
3984                return false;
3985            }
3986            if char == '\n' {
3987                return true;
3988            }
3989        }
3990        true
3991    }
3992
3993    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
3994        while row.0 > 0 {
3995            row.0 -= 1;
3996            if !self.is_line_blank(row) {
3997                return Some(row);
3998            }
3999        }
4000        None
4001    }
4002
4003    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4004        if let Some((_, range)) = self.buffer_line_for_row(row) {
4005            range.end.column - range.start.column
4006        } else {
4007            0
4008        }
4009    }
4010
4011    pub fn buffer_line_for_row(
4012        &self,
4013        row: MultiBufferRow,
4014    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4015        let mut cursor = self.cursor::<Point>();
4016        let point = Point::new(row.0, 0);
4017        cursor.seek(&point);
4018        let region = cursor.region()?;
4019        let overshoot = point.min(region.range.end) - region.range.start;
4020        let buffer_point = region.buffer_range.start + overshoot;
4021        if buffer_point.row > region.buffer_range.end.row {
4022            return None;
4023        }
4024        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4025        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4026            .min(region.buffer_range.end);
4027        Some((region.buffer, line_start..line_end))
4028    }
4029
4030    pub fn max_point(&self) -> Point {
4031        self.text_summary().lines
4032    }
4033
4034    pub fn max_row(&self) -> MultiBufferRow {
4035        MultiBufferRow(self.text_summary().lines.row)
4036    }
4037
4038    pub fn text_summary(&self) -> TextSummary {
4039        self.diff_transforms.summary().output
4040    }
4041
4042    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4043    where
4044        D: TextDimension,
4045        O: ToOffset,
4046    {
4047        let range = range.start.to_offset(self)..range.end.to_offset(self);
4048        let mut cursor = self
4049            .diff_transforms
4050            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4051        cursor.seek(&range.start, Bias::Right);
4052
4053        let Some(first_transform) = cursor.item() else {
4054            return D::from_text_summary(&TextSummary::default());
4055        };
4056
4057        let diff_transform_start = cursor.start().0;
4058        let diff_transform_end = cursor.end().0;
4059        let diff_start = range.start;
4060        let start_overshoot = diff_start - diff_transform_start;
4061        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4062
4063        let mut result = match first_transform {
4064            DiffTransform::BufferContent { .. } => {
4065                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4066                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4067                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4068            }
4069            DiffTransform::DeletedHunk {
4070                buffer_id,
4071                base_text_byte_range,
4072                has_trailing_newline,
4073                ..
4074            } => {
4075                let buffer_start = base_text_byte_range.start + start_overshoot;
4076                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4077                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4078                    panic!("{:?} is in non-existent deleted hunk", range.start)
4079                };
4080
4081                let include_trailing_newline =
4082                    *has_trailing_newline && range.end >= diff_transform_end;
4083                if include_trailing_newline {
4084                    buffer_end -= 1;
4085                }
4086
4087                let mut summary =
4088                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4089
4090                if include_trailing_newline {
4091                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4092                }
4093
4094                summary
4095            }
4096        };
4097        if range.end < diff_transform_end {
4098            return result;
4099        }
4100
4101        cursor.next();
4102        result.add_assign(&D::from_text_summary(
4103            &cursor.summary(&range.end, Bias::Right),
4104        ));
4105
4106        let Some(last_transform) = cursor.item() else {
4107            return result;
4108        };
4109
4110        let overshoot = range.end - cursor.start().0;
4111        let suffix = match last_transform {
4112            DiffTransform::BufferContent { .. } => {
4113                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4114                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4115            }
4116            DiffTransform::DeletedHunk {
4117                base_text_byte_range,
4118                buffer_id,
4119                has_trailing_newline,
4120                ..
4121            } => {
4122                let buffer_end = base_text_byte_range.start + overshoot;
4123                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4124                    panic!("{:?} is in non-existent deleted hunk", range.end)
4125                };
4126
4127                let mut suffix = base_text
4128                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4129                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4130                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4131                }
4132                suffix
4133            }
4134        };
4135
4136        result.add_assign(&suffix);
4137        result
4138    }
4139
4140    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4141    where
4142        D: TextDimension,
4143    {
4144        let mut summary = D::zero(());
4145        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4146        cursor.seek(&range.start, Bias::Right);
4147        if let Some(excerpt) = cursor.item() {
4148            let mut end_before_newline = cursor.end();
4149            if excerpt.has_trailing_newline {
4150                end_before_newline -= ExcerptOffset::new(1);
4151            }
4152
4153            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4154            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4155            let end_in_excerpt =
4156                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4157            summary.add_assign(
4158                &excerpt
4159                    .buffer
4160                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4161            );
4162
4163            if range.end > end_before_newline {
4164                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4165            }
4166
4167            cursor.next();
4168        }
4169
4170        if range.end > *cursor.start() {
4171            summary.add_assign(
4172                &cursor
4173                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4174                    .0,
4175            );
4176            if let Some(excerpt) = cursor.item() {
4177                range.end = cmp::max(*cursor.start(), range.end);
4178
4179                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4180                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4181                summary.add_assign(
4182                    &excerpt
4183                        .buffer
4184                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4185                );
4186            }
4187        }
4188
4189        summary
4190    }
4191
4192    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4193    where
4194        D: TextDimension + Ord + Sub<D, Output = D>,
4195    {
4196        self.summaries_for_anchors([anchor])[0]
4197    }
4198
4199    fn resolve_summary_for_anchor<D>(
4200        &self,
4201        anchor: &Anchor,
4202        excerpt_position: D,
4203        diff_transforms: &mut Cursor<
4204            DiffTransform,
4205            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4206        >,
4207    ) -> D
4208    where
4209        D: TextDimension + Ord + Sub<D, Output = D>,
4210    {
4211        loop {
4212            let transform_end_position = diff_transforms.end().0.0;
4213            let at_transform_end =
4214                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4215            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4216                diff_transforms.next();
4217                continue;
4218            }
4219
4220            let mut position = diff_transforms.start().1.0;
4221            match diff_transforms.item() {
4222                Some(DiffTransform::DeletedHunk {
4223                    buffer_id,
4224                    base_text_byte_range,
4225                    ..
4226                }) => {
4227                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4228                        && let Some(base_text) =
4229                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4230                        && base_text.can_resolve(diff_base_anchor)
4231                    {
4232                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4233                        if base_text_offset >= base_text_byte_range.start
4234                            && base_text_offset <= base_text_byte_range.end
4235                        {
4236                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4237                                base_text_byte_range.start..base_text_offset,
4238                            );
4239                            position.add_assign(&position_in_hunk);
4240                        } else if at_transform_end {
4241                            diff_transforms.next();
4242                            continue;
4243                        }
4244                    }
4245                }
4246                _ => {
4247                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4248                        diff_transforms.next();
4249                        continue;
4250                    }
4251                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4252                    position.add_assign(&overshoot);
4253                }
4254            }
4255
4256            return position;
4257        }
4258    }
4259
4260    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4261        let mut cursor = self
4262            .excerpts
4263            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
4264        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4265
4266        cursor.seek(&Some(locator), Bias::Left);
4267        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
4268            cursor.prev();
4269        }
4270
4271        let mut position = cursor.start().1;
4272        if let Some(excerpt) = cursor.item()
4273            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
4274        {
4275            let excerpt_buffer_start = excerpt
4276                .buffer
4277                .offset_for_anchor(&excerpt.range.context.start);
4278            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4279            let buffer_position = cmp::min(
4280                excerpt_buffer_end,
4281                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4282            );
4283            if buffer_position > excerpt_buffer_start {
4284                position.value += buffer_position - excerpt_buffer_start;
4285            }
4286        }
4287        position
4288    }
4289
4290    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4291        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4292            excerpt_id = *replacement;
4293        }
4294        excerpt_id
4295    }
4296
4297    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4298    where
4299        D: TextDimension + Ord + Sub<D, Output = D>,
4300        I: 'a + IntoIterator<Item = &'a Anchor>,
4301    {
4302        let mut anchors = anchors.into_iter().peekable();
4303        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4304        let mut diff_transforms_cursor = self
4305            .diff_transforms
4306            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(());
4307        diff_transforms_cursor.next();
4308
4309        let mut summaries = Vec::new();
4310        while let Some(anchor) = anchors.peek() {
4311            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4312
4313            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
4314                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
4315            });
4316
4317            let locator = self.excerpt_locator_for_id(excerpt_id);
4318            cursor.seek_forward(locator, Bias::Left);
4319            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
4320                cursor.prev();
4321            }
4322
4323            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4324            if let Some(excerpt) = cursor.item() {
4325                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4326                    let position = self.resolve_summary_for_anchor(
4327                        &Anchor::min(),
4328                        excerpt_start_position,
4329                        &mut diff_transforms_cursor,
4330                    );
4331                    summaries.extend(excerpt_anchors.map(|_| position));
4332                    continue;
4333                }
4334                let excerpt_buffer_start =
4335                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4336                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4337                for (buffer_summary, anchor) in excerpt
4338                    .buffer
4339                    .summaries_for_anchors_with_payload::<D, _, _>(
4340                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4341                    )
4342                {
4343                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4344                    let mut position = excerpt_start_position;
4345                    if summary > excerpt_buffer_start {
4346                        position.add_assign(&(summary - excerpt_buffer_start));
4347                    }
4348
4349                    if position > diff_transforms_cursor.start().0.0 {
4350                        diff_transforms_cursor
4351                            .seek_forward(&ExcerptDimension(position), Bias::Left);
4352                    }
4353
4354                    summaries.push(self.resolve_summary_for_anchor(
4355                        anchor,
4356                        position,
4357                        &mut diff_transforms_cursor,
4358                    ));
4359                }
4360            } else {
4361                diff_transforms_cursor
4362                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
4363                let position = self.resolve_summary_for_anchor(
4364                    &Anchor::max(),
4365                    excerpt_start_position,
4366                    &mut diff_transforms_cursor,
4367                );
4368                summaries.extend(excerpt_anchors.map(|_| position));
4369            }
4370        }
4371
4372        summaries
4373    }
4374
4375    pub fn dimensions_from_points<'a, D>(
4376        &'a self,
4377        points: impl 'a + IntoIterator<Item = Point>,
4378    ) -> impl 'a + Iterator<Item = D>
4379    where
4380        D: TextDimension + Sub<D, Output = D>,
4381    {
4382        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4383        cursor.seek(&DimensionPair {
4384            key: Point::default(),
4385            value: None,
4386        });
4387        let mut points = points.into_iter();
4388        iter::from_fn(move || {
4389            let point = points.next()?;
4390
4391            cursor.seek_forward(&DimensionPair {
4392                key: point,
4393                value: None,
4394            });
4395
4396            if let Some(region) = cursor.region() {
4397                let overshoot = point - region.range.start.key;
4398                let buffer_point = region.buffer_range.start.key + overshoot;
4399                let mut position = region.range.start.value.unwrap();
4400                position.add_assign(
4401                    &region
4402                        .buffer
4403                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4404                );
4405                if point == region.range.end.key && region.has_trailing_newline {
4406                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4407                }
4408                Some(position)
4409            } else {
4410                Some(D::from_text_summary(&self.text_summary()))
4411            }
4412        })
4413    }
4414
4415    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4416    where
4417        I: 'a + IntoIterator<Item = &'a Anchor>,
4418    {
4419        let mut anchors = anchors.into_iter().enumerate().peekable();
4420        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4421        cursor.next();
4422
4423        let mut result = Vec::new();
4424
4425        while let Some((_, anchor)) = anchors.peek() {
4426            let old_excerpt_id = anchor.excerpt_id;
4427
4428            // Find the location where this anchor's excerpt should be.
4429            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4430            cursor.seek_forward(&Some(old_locator), Bias::Left);
4431
4432            let next_excerpt = cursor.item();
4433            let prev_excerpt = cursor.prev_item();
4434
4435            // Process all of the anchors for this excerpt.
4436            while let Some((anchor_ix, &anchor)) =
4437                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
4438            {
4439                let mut anchor = anchor;
4440
4441                // Leave min and max anchors unchanged if invalid or
4442                // if the old excerpt still exists at this location
4443                let mut kept_position = next_excerpt
4444                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
4445                    || old_excerpt_id == ExcerptId::max()
4446                    || old_excerpt_id == ExcerptId::min();
4447
4448                // If the old excerpt no longer exists at this location, then attempt to
4449                // find an equivalent position for this anchor in an adjacent excerpt.
4450                if !kept_position {
4451                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4452                        if excerpt.contains(&anchor) {
4453                            anchor.excerpt_id = excerpt.id;
4454                            kept_position = true;
4455                            break;
4456                        }
4457                    }
4458                }
4459
4460                // If there's no adjacent excerpt that contains the anchor's position,
4461                // then report that the anchor has lost its position.
4462                if !kept_position {
4463                    anchor = if let Some(excerpt) = next_excerpt {
4464                        let mut text_anchor = excerpt
4465                            .range
4466                            .context
4467                            .start
4468                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4469                        if text_anchor
4470                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4471                            .is_gt()
4472                        {
4473                            text_anchor = excerpt.range.context.end;
4474                        }
4475                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4476                    } else if let Some(excerpt) = prev_excerpt {
4477                        let mut text_anchor = excerpt
4478                            .range
4479                            .context
4480                            .end
4481                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4482                        if text_anchor
4483                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4484                            .is_lt()
4485                        {
4486                            text_anchor = excerpt.range.context.start;
4487                        }
4488                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4489                    } else if anchor.text_anchor.bias == Bias::Left {
4490                        Anchor::min()
4491                    } else {
4492                        Anchor::max()
4493                    };
4494                }
4495
4496                result.push((anchor_ix, anchor, kept_position));
4497            }
4498        }
4499        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4500        result
4501    }
4502
4503    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4504        self.anchor_at(position, Bias::Left)
4505    }
4506
4507    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4508        self.anchor_at(position, Bias::Right)
4509    }
4510
4511    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4512        let offset = position.to_offset(self);
4513
4514        // Find the given position in the diff transforms. Determine the corresponding
4515        // offset in the excerpts, and whether the position is within a deleted hunk.
4516        let mut diff_transforms = self
4517            .diff_transforms
4518            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4519        diff_transforms.seek(&offset, Bias::Right);
4520
4521        if offset == diff_transforms.start().0
4522            && bias == Bias::Left
4523            && let Some(prev_item) = diff_transforms.prev_item()
4524            && let DiffTransform::DeletedHunk { .. } = prev_item
4525        {
4526            diff_transforms.prev();
4527        }
4528        let offset_in_transform = offset - diff_transforms.start().0;
4529        let mut excerpt_offset = diff_transforms.start().1;
4530        let mut diff_base_anchor = None;
4531        if let Some(DiffTransform::DeletedHunk {
4532            buffer_id,
4533            base_text_byte_range,
4534            has_trailing_newline,
4535            ..
4536        }) = diff_transforms.item()
4537        {
4538            let diff = self.diffs.get(buffer_id).expect("missing diff");
4539            if offset_in_transform > base_text_byte_range.len() {
4540                debug_assert!(*has_trailing_newline);
4541                bias = Bias::Right;
4542            } else {
4543                diff_base_anchor = Some(
4544                    diff.base_text()
4545                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4546                );
4547                bias = Bias::Left;
4548            }
4549        } else {
4550            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4551        };
4552
4553        let mut excerpts = self
4554            .excerpts
4555            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
4556        excerpts.seek(&excerpt_offset, Bias::Right);
4557        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4558            excerpts.prev();
4559        }
4560        if let Some(excerpt) = excerpts.item() {
4561            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4562            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
4563                overshoot -= 1;
4564                bias = Bias::Right;
4565            }
4566
4567            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4568            let text_anchor =
4569                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4570            let anchor = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor);
4571            match diff_base_anchor {
4572                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
4573                None => anchor,
4574            }
4575        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4576            Anchor::min()
4577        } else {
4578            Anchor::max()
4579        }
4580    }
4581
4582    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
4583    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
4584        let (excerpt, buffer, _) = self.as_singleton()?;
4585        Some(Anchor::in_buffer(*excerpt, buffer, text_anchor))
4586    }
4587
4588    /// Returns an anchor for the given excerpt and text anchor,
4589    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4590    pub fn anchor_range_in_excerpt(
4591        &self,
4592        excerpt_id: ExcerptId,
4593        text_anchor: Range<text::Anchor>,
4594    ) -> Option<Range<Anchor>> {
4595        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4596        let excerpt = self.excerpt(excerpt_id)?;
4597
4598        Some(
4599            self.anchor_in_excerpt_(excerpt, text_anchor.start)?
4600                ..self.anchor_in_excerpt_(excerpt, text_anchor.end)?,
4601        )
4602    }
4603
4604    /// Returns an anchor for the given excerpt and text anchor,
4605    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4606    pub fn anchor_in_excerpt(
4607        &self,
4608        excerpt_id: ExcerptId,
4609        text_anchor: text::Anchor,
4610    ) -> Option<Anchor> {
4611        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4612        let excerpt = self.excerpt(excerpt_id)?;
4613        self.anchor_in_excerpt_(excerpt, text_anchor)
4614    }
4615
4616    fn anchor_in_excerpt_(&self, excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
4617        match text_anchor.buffer_id {
4618            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
4619            Some(_) => return None,
4620            None if text_anchor == text::Anchor::MAX || text_anchor == text::Anchor::MIN => {
4621                return Some(Anchor::in_buffer(
4622                    excerpt.id,
4623                    excerpt.buffer_id,
4624                    text_anchor,
4625                ));
4626            }
4627            None => return None,
4628        }
4629
4630        let context = &excerpt.range.context;
4631        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
4632            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
4633        {
4634            return None;
4635        }
4636
4637        Some(Anchor::in_buffer(
4638            excerpt.id,
4639            excerpt.buffer_id,
4640            text_anchor,
4641        ))
4642    }
4643
4644    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4645        Some(self.excerpt(excerpt_id)?.range.context.clone())
4646    }
4647
4648    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4649        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4650            true
4651        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4652            excerpt.buffer.can_resolve(&anchor.text_anchor)
4653        } else {
4654            false
4655        }
4656    }
4657
4658    pub fn excerpts(
4659        &self,
4660    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4661        self.excerpts
4662            .iter()
4663            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4664    }
4665
4666    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
4667        let excerpts = self.excerpts.cursor(());
4668        let diff_transforms = self.diff_transforms.cursor(());
4669        MultiBufferCursor {
4670            excerpts,
4671            diff_transforms,
4672            diffs: &self.diffs,
4673            cached_region: None,
4674        }
4675    }
4676
4677    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4678        let start_locator = self.excerpt_locator_for_id(excerpt_id);
4679        let mut excerpts = self
4680            .excerpts
4681            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(());
4682        excerpts.seek(&Some(start_locator), Bias::Left);
4683        excerpts.prev();
4684
4685        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(());
4686        diff_transforms.seek(&excerpts.start().1, Bias::Left);
4687        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
4688            diff_transforms.next();
4689        }
4690
4691        let excerpt = excerpts.item()?;
4692        Some(MultiBufferExcerpt {
4693            excerpt,
4694            offset: diff_transforms.start().output_dimension.0,
4695            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4696            excerpt_offset: excerpts.start().1.clone(),
4697            diff_transforms,
4698        })
4699    }
4700
4701    pub fn excerpt_boundaries_in_range<R, T>(
4702        &self,
4703        range: R,
4704    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4705    where
4706        R: RangeBounds<T>,
4707        T: ToOffset,
4708    {
4709        let start_offset;
4710        let start = match range.start_bound() {
4711            Bound::Included(start) => {
4712                start_offset = start.to_offset(self);
4713                Bound::Included(start_offset)
4714            }
4715            Bound::Excluded(_) => {
4716                panic!("not supported")
4717            }
4718            Bound::Unbounded => {
4719                start_offset = 0;
4720                Bound::Unbounded
4721            }
4722        };
4723        let end = match range.end_bound() {
4724            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4725            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4726            Bound::Unbounded => Bound::Unbounded,
4727        };
4728        let bounds = (start, end);
4729
4730        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4731        cursor.seek(&DimensionPair {
4732            key: start_offset,
4733            value: None,
4734        });
4735
4736        if cursor
4737            .region()
4738            .is_some_and(|region| bounds.contains(&region.range.start.key))
4739        {
4740            cursor.prev_excerpt();
4741        } else {
4742            cursor.seek_to_start_of_current_excerpt();
4743        }
4744        let mut prev_region = cursor.region();
4745
4746        cursor.next_excerpt();
4747
4748        iter::from_fn(move || {
4749            loop {
4750                if self.singleton {
4751                    return None;
4752                }
4753
4754                let next_region = cursor.region()?;
4755                cursor.next_excerpt();
4756                if !bounds.contains(&next_region.range.start.key) {
4757                    prev_region = Some(next_region);
4758                    continue;
4759                }
4760
4761                let next_region_start = next_region.range.start.value.unwrap();
4762                let next_region_end = if let Some(region) = cursor.region() {
4763                    region.range.start.value.unwrap()
4764                } else {
4765                    self.max_point()
4766                };
4767
4768                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4769                    id: region.excerpt.id,
4770                    buffer: region.excerpt.buffer.clone(),
4771                    buffer_id: region.excerpt.buffer_id,
4772                    range: region.excerpt.range.clone(),
4773                    end_row: MultiBufferRow(next_region_start.row),
4774                });
4775
4776                let next = ExcerptInfo {
4777                    id: next_region.excerpt.id,
4778                    buffer: next_region.excerpt.buffer.clone(),
4779                    buffer_id: next_region.excerpt.buffer_id,
4780                    range: next_region.excerpt.range.clone(),
4781                    end_row: if next_region.excerpt.has_trailing_newline {
4782                        MultiBufferRow(next_region_end.row - 1)
4783                    } else {
4784                        MultiBufferRow(next_region_end.row)
4785                    },
4786                };
4787
4788                let row = MultiBufferRow(next_region_start.row);
4789
4790                prev_region = Some(next_region);
4791
4792                return Some(ExcerptBoundary { row, prev, next });
4793            }
4794        })
4795    }
4796
4797    pub fn edit_count(&self) -> usize {
4798        self.edit_count
4799    }
4800
4801    pub fn non_text_state_update_count(&self) -> usize {
4802        self.non_text_state_update_count
4803    }
4804
4805    /// Returns the smallest enclosing bracket ranges containing the given range or
4806    /// None if no brackets contain range or the range is not contained in a single
4807    /// excerpt
4808    ///
4809    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4810    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4811        &self,
4812        range: Range<T>,
4813        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4814    ) -> Option<(Range<usize>, Range<usize>)> {
4815        let range = range.start.to_offset(self)..range.end.to_offset(self);
4816        let mut excerpt = self.excerpt_containing(range.clone())?;
4817        let buffer = excerpt.buffer();
4818        let excerpt_buffer_range = excerpt.buffer_range();
4819
4820        // Filter to ranges contained in the excerpt
4821        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4822            excerpt_buffer_range.contains(&open.start)
4823                && excerpt_buffer_range.contains(&close.end)
4824                && range_filter.is_none_or(|filter| filter(buffer, open, close))
4825        };
4826
4827        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4828            excerpt.map_range_to_buffer(range),
4829            Some(&range_filter),
4830        )?;
4831
4832        Some((
4833            excerpt.map_range_from_buffer(open),
4834            excerpt.map_range_from_buffer(close),
4835        ))
4836    }
4837
4838    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4839    /// not contained in a single excerpt
4840    pub fn enclosing_bracket_ranges<T: ToOffset>(
4841        &self,
4842        range: Range<T>,
4843    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4844        let range = range.start.to_offset(self)..range.end.to_offset(self);
4845        let mut excerpt = self.excerpt_containing(range.clone())?;
4846
4847        Some(
4848            excerpt
4849                .buffer()
4850                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
4851                .filter_map(move |pair| {
4852                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
4853                        Some((
4854                            excerpt.map_range_from_buffer(pair.open_range),
4855                            excerpt.map_range_from_buffer(pair.close_range),
4856                        ))
4857                    } else {
4858                        None
4859                    }
4860                }),
4861        )
4862    }
4863
4864    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4865    /// not contained in a single excerpt
4866    pub fn text_object_ranges<T: ToOffset>(
4867        &self,
4868        range: Range<T>,
4869        options: TreeSitterOptions,
4870    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
4871        let range = range.start.to_offset(self)..range.end.to_offset(self);
4872        self.excerpt_containing(range.clone())
4873            .map(|mut excerpt| {
4874                excerpt
4875                    .buffer()
4876                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
4877                    .filter_map(move |(range, text_object)| {
4878                        if excerpt.contains_buffer_range(range.clone()) {
4879                            Some((excerpt.map_range_from_buffer(range), text_object))
4880                        } else {
4881                            None
4882                        }
4883                    })
4884            })
4885            .into_iter()
4886            .flatten()
4887    }
4888
4889    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
4890    /// not contained in a single excerpt
4891    pub fn bracket_ranges<T: ToOffset>(
4892        &self,
4893        range: Range<T>,
4894    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4895        let range = range.start.to_offset(self)..range.end.to_offset(self);
4896        let mut excerpt = self.excerpt_containing(range.clone())?;
4897
4898        Some(
4899            excerpt
4900                .buffer()
4901                .bracket_ranges(excerpt.map_range_to_buffer(range))
4902                .filter_map(move |pair| {
4903                    let buffer_range = pair.open_range.start..pair.close_range.end;
4904                    if excerpt.contains_buffer_range(buffer_range) {
4905                        Some((
4906                            excerpt.map_range_from_buffer(pair.open_range),
4907                            excerpt.map_range_from_buffer(pair.close_range),
4908                        ))
4909                    } else {
4910                        None
4911                    }
4912                }),
4913        )
4914    }
4915
4916    pub fn redacted_ranges<'a, T: ToOffset>(
4917        &'a self,
4918        range: Range<T>,
4919        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
4920    ) -> impl Iterator<Item = Range<usize>> + 'a {
4921        let range = range.start.to_offset(self)..range.end.to_offset(self);
4922        self.lift_buffer_metadata(range, move |buffer, range| {
4923            if redaction_enabled(buffer.file()) {
4924                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
4925            } else {
4926                None
4927            }
4928        })
4929        .map(|(range, _, _)| range)
4930    }
4931
4932    pub fn runnable_ranges(
4933        &self,
4934        range: Range<Anchor>,
4935    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
4936        let range = range.start.to_offset(self)..range.end.to_offset(self);
4937        self.lift_buffer_metadata(range, move |buffer, range| {
4938            Some(
4939                buffer
4940                    .runnable_ranges(range.clone())
4941                    .filter(move |runnable| {
4942                        runnable.run_range.start >= range.start
4943                            && runnable.run_range.end < range.end
4944                    })
4945                    .map(|runnable| (runnable.run_range.clone(), runnable)),
4946            )
4947        })
4948        .map(|(run_range, runnable, _)| language::RunnableRange {
4949            run_range,
4950            ..runnable
4951        })
4952    }
4953
4954    pub fn line_indents(
4955        &self,
4956        start_row: MultiBufferRow,
4957        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
4958    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
4959        let max_point = self.max_point();
4960        let mut cursor = self.cursor::<Point>();
4961        cursor.seek(&Point::new(start_row.0, 0));
4962        iter::from_fn(move || {
4963            let mut region = cursor.region()?;
4964            while !buffer_filter(&region.excerpt.buffer) {
4965                cursor.next();
4966                region = cursor.region()?;
4967            }
4968            let overshoot = start_row.0.saturating_sub(region.range.start.row);
4969            let buffer_start_row =
4970                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
4971
4972            let buffer_end_row = if region.is_main_buffer
4973                && (region.has_trailing_newline || region.range.end == max_point)
4974            {
4975                region.buffer_range.end.row
4976            } else {
4977                region.buffer_range.end.row.saturating_sub(1)
4978            };
4979
4980            let line_indents = region
4981                .buffer
4982                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
4983            cursor.next();
4984            Some(line_indents.map(move |(buffer_row, indent)| {
4985                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
4986                (MultiBufferRow(row), indent, &region.excerpt.buffer)
4987            }))
4988        })
4989        .flatten()
4990    }
4991
4992    pub fn reversed_line_indents(
4993        &self,
4994        end_row: MultiBufferRow,
4995        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
4996    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
4997        let max_point = self.max_point();
4998        let mut cursor = self.cursor::<Point>();
4999        cursor.seek(&Point::new(end_row.0, 0));
5000        iter::from_fn(move || {
5001            let mut region = cursor.region()?;
5002            while !buffer_filter(&region.excerpt.buffer) {
5003                cursor.prev();
5004                region = cursor.region()?;
5005            }
5006
5007            let buffer_start_row = region.buffer_range.start.row;
5008            let buffer_end_row = if region.is_main_buffer
5009                && (region.has_trailing_newline || region.range.end == max_point)
5010            {
5011                region.buffer_range.end.row + 1
5012            } else {
5013                region.buffer_range.end.row
5014            };
5015
5016            let overshoot = end_row.0 - region.range.start.row;
5017            let buffer_end_row =
5018                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5019
5020            let line_indents = region
5021                .buffer
5022                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5023            cursor.prev();
5024            Some(line_indents.map(move |(buffer_row, indent)| {
5025                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5026                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5027            }))
5028        })
5029        .flatten()
5030    }
5031
5032    pub async fn enclosing_indent(
5033        &self,
5034        mut target_row: MultiBufferRow,
5035    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5036        let max_row = MultiBufferRow(self.max_point().row);
5037        if target_row >= max_row {
5038            return None;
5039        }
5040
5041        let mut target_indent = self.line_indent_for_row(target_row);
5042
5043        // If the current row is at the start of an indented block, we want to return this
5044        // block as the enclosing indent.
5045        if !target_indent.is_line_empty() && target_row < max_row {
5046            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5047            if !next_line_indent.is_line_empty()
5048                && target_indent.raw_len() < next_line_indent.raw_len()
5049            {
5050                target_indent = next_line_indent;
5051                target_row.0 += 1;
5052            }
5053        }
5054
5055        const SEARCH_ROW_LIMIT: u32 = 25000;
5056        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5057        const YIELD_INTERVAL: u32 = 100;
5058
5059        let mut accessed_row_counter = 0;
5060
5061        // If there is a blank line at the current row, search for the next non indented lines
5062        if target_indent.is_line_empty() {
5063            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5064            let end =
5065                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5066
5067            let mut non_empty_line_above = None;
5068            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5069                if row < start {
5070                    break;
5071                }
5072                accessed_row_counter += 1;
5073                if accessed_row_counter == YIELD_INTERVAL {
5074                    accessed_row_counter = 0;
5075                    yield_now().await;
5076                }
5077                if !indent.is_line_empty() {
5078                    non_empty_line_above = Some((row, indent));
5079                    break;
5080                }
5081            }
5082
5083            let mut non_empty_line_below = None;
5084            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5085                if row > end {
5086                    break;
5087                }
5088                accessed_row_counter += 1;
5089                if accessed_row_counter == YIELD_INTERVAL {
5090                    accessed_row_counter = 0;
5091                    yield_now().await;
5092                }
5093                if !indent.is_line_empty() {
5094                    non_empty_line_below = Some((row, indent));
5095                    break;
5096                }
5097            }
5098
5099            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5100                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5101                    if above_indent.raw_len() >= below_indent.raw_len() {
5102                        (above_row, above_indent)
5103                    } else {
5104                        (below_row, below_indent)
5105                    }
5106                }
5107                (Some(above), None) => above,
5108                (None, Some(below)) => below,
5109                _ => return None,
5110            };
5111
5112            target_indent = indent;
5113            target_row = row;
5114        }
5115
5116        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5117        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5118
5119        let mut start_indent = None;
5120        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5121            if row < start {
5122                break;
5123            }
5124            accessed_row_counter += 1;
5125            if accessed_row_counter == YIELD_INTERVAL {
5126                accessed_row_counter = 0;
5127                yield_now().await;
5128            }
5129            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5130                start_indent = Some((row, indent));
5131                break;
5132            }
5133        }
5134        let (start_row, start_indent_size) = start_indent?;
5135
5136        let mut end_indent = (end, None);
5137        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5138            if row > end {
5139                break;
5140            }
5141            accessed_row_counter += 1;
5142            if accessed_row_counter == YIELD_INTERVAL {
5143                accessed_row_counter = 0;
5144                yield_now().await;
5145            }
5146            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5147                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5148                break;
5149            }
5150        }
5151        let (end_row, end_indent_size) = end_indent;
5152
5153        let indent = if let Some(end_indent_size) = end_indent_size {
5154            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5155                start_indent_size
5156            } else {
5157                end_indent_size
5158            }
5159        } else {
5160            start_indent_size
5161        };
5162
5163        Some((start_row..end_row, indent))
5164    }
5165
5166    pub fn indent_guides_in_range<T: ToPoint>(
5167        &self,
5168        range: Range<T>,
5169        ignore_disabled_for_language: bool,
5170        cx: &App,
5171    ) -> impl Iterator<Item = IndentGuide> {
5172        let range = range.start.to_point(self)..range.end.to_point(self);
5173        let start_row = MultiBufferRow(range.start.row);
5174        let end_row = MultiBufferRow(range.end.row);
5175
5176        let mut row_indents = self.line_indents(start_row, |buffer| {
5177            let settings =
5178                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5179            settings.indent_guides.enabled || ignore_disabled_for_language
5180        });
5181
5182        let mut result = Vec::new();
5183        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5184
5185        let mut prev_settings = None;
5186        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5187            if first_row > end_row {
5188                break;
5189            }
5190            let current_depth = indent_stack.len() as u32;
5191
5192            // Avoid retrieving the language settings repeatedly for every buffer row.
5193            if let Some((prev_buffer_id, _)) = &prev_settings
5194                && prev_buffer_id != &buffer.remote_id()
5195            {
5196                prev_settings.take();
5197            }
5198            let settings = &prev_settings
5199                .get_or_insert_with(|| {
5200                    (
5201                        buffer.remote_id(),
5202                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5203                    )
5204                })
5205                .1;
5206            let tab_size = settings.tab_size.get();
5207
5208            // When encountering empty, continue until found useful line indent
5209            // then add to the indent stack with the depth found
5210            let mut found_indent = false;
5211            let mut last_row = first_row;
5212            if line_indent.is_line_blank() {
5213                while !found_indent {
5214                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5215                        break;
5216                    };
5217                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5218                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5219                        break;
5220                    }
5221
5222                    if new_line_indent.is_line_blank() {
5223                        continue;
5224                    }
5225                    last_row = target_row.min(end_row);
5226                    line_indent = new_line_indent;
5227                    found_indent = true;
5228                    break;
5229                }
5230            } else {
5231                found_indent = true
5232            }
5233
5234            let depth = if found_indent {
5235                line_indent.len(tab_size) / tab_size
5236            } else {
5237                0
5238            };
5239
5240            match depth.cmp(&current_depth) {
5241                cmp::Ordering::Less => {
5242                    for _ in 0..(current_depth - depth) {
5243                        let mut indent = indent_stack.pop().unwrap();
5244                        if last_row != first_row {
5245                            // In this case, we landed on an empty row, had to seek forward,
5246                            // and discovered that the indent we where on is ending.
5247                            // This means that the last display row must
5248                            // be on line that ends this indent range, so we
5249                            // should display the range up to the first non-empty line
5250                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5251                        }
5252
5253                        result.push(indent)
5254                    }
5255                }
5256                cmp::Ordering::Greater => {
5257                    for next_depth in current_depth..depth {
5258                        indent_stack.push(IndentGuide {
5259                            buffer_id: buffer.remote_id(),
5260                            start_row: first_row,
5261                            end_row: last_row,
5262                            depth: next_depth,
5263                            tab_size,
5264                            settings: settings.indent_guides.clone(),
5265                        });
5266                    }
5267                }
5268                _ => {}
5269            }
5270
5271            for indent in indent_stack.iter_mut() {
5272                indent.end_row = last_row;
5273            }
5274        }
5275
5276        result.extend(indent_stack);
5277        result.into_iter()
5278    }
5279
5280    pub fn trailing_excerpt_update_count(&self) -> usize {
5281        self.trailing_excerpt_update_count
5282    }
5283
5284    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5285        self.point_to_buffer_offset(point)
5286            .and_then(|(buffer, _)| buffer.file())
5287    }
5288
5289    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5290        self.point_to_buffer_offset(point)
5291            .and_then(|(buffer, offset)| buffer.language_at(offset))
5292    }
5293
5294    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5295        self.excerpts
5296            .first()
5297            .map(|excerpt| &excerpt.buffer)
5298            .map(|buffer| {
5299                language_settings(
5300                    buffer.language().map(|language| language.name()),
5301                    buffer.file(),
5302                    cx,
5303                )
5304            })
5305            .unwrap_or_else(move || self.language_settings_at(0, cx))
5306    }
5307
5308    pub fn language_settings_at<'a, T: ToOffset>(
5309        &'a self,
5310        point: T,
5311        cx: &'a App,
5312    ) -> Cow<'a, LanguageSettings> {
5313        let mut language = None;
5314        let mut file = None;
5315        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5316            language = buffer.language_at(offset);
5317            file = buffer.file();
5318        }
5319        language_settings(language.map(|l| l.name()), file, cx)
5320    }
5321
5322    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5323        self.point_to_buffer_offset(point)
5324            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5325    }
5326
5327    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5328        self.point_to_buffer_offset(point)
5329            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5330            .unwrap_or_default()
5331    }
5332
5333    pub fn language_indent_size_at<T: ToOffset>(
5334        &self,
5335        position: T,
5336        cx: &App,
5337    ) -> Option<IndentSize> {
5338        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5339        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5340    }
5341
5342    pub fn is_dirty(&self) -> bool {
5343        self.is_dirty
5344    }
5345
5346    pub fn has_deleted_file(&self) -> bool {
5347        self.has_deleted_file
5348    }
5349
5350    pub fn has_conflict(&self) -> bool {
5351        self.has_conflict
5352    }
5353
5354    pub fn has_diagnostics(&self) -> bool {
5355        self.excerpts
5356            .iter()
5357            .any(|excerpt| excerpt.buffer.has_diagnostics())
5358    }
5359
5360    pub fn diagnostic_group(
5361        &self,
5362        buffer_id: BufferId,
5363        group_id: usize,
5364    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
5365        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
5366            if buffer.remote_id() != buffer_id {
5367                return None;
5368            };
5369            Some(
5370                buffer
5371                    .diagnostics_in_range(range, false)
5372                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
5373                    .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
5374            )
5375        })
5376        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5377    }
5378
5379    pub fn diagnostics_in_range<'a, T>(
5380        &'a self,
5381        range: Range<T>,
5382    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, T>> + 'a
5383    where
5384        T: 'a
5385            + text::ToOffset
5386            + text::FromAnchor
5387            + TextDimension
5388            + Ord
5389            + Sub<T, Output = T>
5390            + fmt::Debug,
5391    {
5392        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5393            Some(
5394                buffer
5395                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5396                    .map(|entry| (entry.range, entry.diagnostic)),
5397            )
5398        })
5399        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5400    }
5401
5402    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
5403        &'a self,
5404        range: Range<T>,
5405    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, T>)> + 'a
5406    where
5407        T: 'a
5408            + text::ToOffset
5409            + text::FromAnchor
5410            + TextDimension
5411            + Ord
5412            + Sub<T, Output = T>
5413            + fmt::Debug,
5414    {
5415        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5416            Some(
5417                buffer
5418                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5419                    .map(|entry| (entry.range, entry.diagnostic)),
5420            )
5421        })
5422        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
5423    }
5424
5425    pub fn syntax_ancestor<T: ToOffset>(
5426        &self,
5427        range: Range<T>,
5428    ) -> Option<(tree_sitter::Node<'_>, Range<usize>)> {
5429        let range = range.start.to_offset(self)..range.end.to_offset(self);
5430        let mut excerpt = self.excerpt_containing(range.clone())?;
5431        let node = excerpt
5432            .buffer()
5433            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5434        let node_range = node.byte_range();
5435        if !excerpt.contains_buffer_range(node_range.clone()) {
5436            return None;
5437        };
5438        Some((node, excerpt.map_range_from_buffer(node_range)))
5439    }
5440
5441    pub fn syntax_next_sibling<T: ToOffset>(
5442        &self,
5443        range: Range<T>,
5444    ) -> Option<tree_sitter::Node<'_>> {
5445        let range = range.start.to_offset(self)..range.end.to_offset(self);
5446        let mut excerpt = self.excerpt_containing(range.clone())?;
5447        excerpt
5448            .buffer()
5449            .syntax_next_sibling(excerpt.map_range_to_buffer(range))
5450    }
5451
5452    pub fn syntax_prev_sibling<T: ToOffset>(
5453        &self,
5454        range: Range<T>,
5455    ) -> Option<tree_sitter::Node<'_>> {
5456        let range = range.start.to_offset(self)..range.end.to_offset(self);
5457        let mut excerpt = self.excerpt_containing(range.clone())?;
5458        excerpt
5459            .buffer()
5460            .syntax_prev_sibling(excerpt.map_range_to_buffer(range))
5461    }
5462
5463    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5464        let (excerpt_id, _, buffer) = self.as_singleton()?;
5465        let outline = buffer.outline(theme);
5466        Some(Outline::new(
5467            outline
5468                .items
5469                .into_iter()
5470                .flat_map(|item| {
5471                    Some(OutlineItem {
5472                        depth: item.depth,
5473                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
5474                        source_range_for_text: self
5475                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
5476                        text: item.text,
5477                        highlight_ranges: item.highlight_ranges,
5478                        name_ranges: item.name_ranges,
5479                        body_range: item.body_range.and_then(|body_range| {
5480                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
5481                        }),
5482                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5483                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
5484                        }),
5485                    })
5486                })
5487                .collect(),
5488        ))
5489    }
5490
5491    pub fn symbols_containing<T: ToOffset>(
5492        &self,
5493        offset: T,
5494        theme: Option<&SyntaxTheme>,
5495    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5496        let anchor = self.anchor_before(offset);
5497        let excerpt_id = anchor.excerpt_id;
5498        let excerpt = self.excerpt(excerpt_id)?;
5499        let buffer_id = excerpt.buffer_id;
5500        Some((
5501            buffer_id,
5502            excerpt
5503                .buffer
5504                .symbols_containing(anchor.text_anchor, theme)
5505                .into_iter()
5506                .flat_map(|item| {
5507                    Some(OutlineItem {
5508                        depth: item.depth,
5509                        source_range_for_text: Anchor::range_in_buffer(
5510                            excerpt_id,
5511                            buffer_id,
5512                            item.source_range_for_text,
5513                        ),
5514                        range: Anchor::range_in_buffer(excerpt_id, buffer_id, item.range),
5515                        text: item.text,
5516                        highlight_ranges: item.highlight_ranges,
5517                        name_ranges: item.name_ranges,
5518                        body_range: item.body_range.map(|body_range| {
5519                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5520                        }),
5521                        annotation_range: item.annotation_range.map(|body_range| {
5522                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5523                        }),
5524                    })
5525                })
5526                .collect(),
5527        ))
5528    }
5529
5530    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5531        if id == ExcerptId::min() {
5532            Locator::min_ref()
5533        } else if id == ExcerptId::max() {
5534            Locator::max_ref()
5535        } else {
5536            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
5537            if let Some(entry) = item
5538                && entry.id == id
5539            {
5540                return &entry.locator;
5541            }
5542            panic!("invalid excerpt id {id:?}")
5543        }
5544    }
5545
5546    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5547    fn excerpt_locators_for_ids(
5548        &self,
5549        ids: impl IntoIterator<Item = ExcerptId>,
5550    ) -> SmallVec<[Locator; 1]> {
5551        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5552        sorted_ids.sort_unstable();
5553        sorted_ids.dedup();
5554        let mut locators = SmallVec::new();
5555
5556        while sorted_ids.last() == Some(&ExcerptId::max()) {
5557            sorted_ids.pop();
5558            locators.push(Locator::max());
5559        }
5560
5561        let mut sorted_ids = sorted_ids.into_iter().peekable();
5562        locators.extend(
5563            sorted_ids
5564                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
5565                .map(|_| Locator::min()),
5566        );
5567
5568        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
5569        for id in sorted_ids {
5570            if cursor.seek_forward(&id, Bias::Left) {
5571                locators.push(cursor.item().unwrap().locator.clone());
5572            } else {
5573                panic!("invalid excerpt id {:?}", id);
5574            }
5575        }
5576
5577        locators.sort_unstable();
5578        locators
5579    }
5580
5581    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5582        Some(self.excerpt(excerpt_id)?.buffer_id)
5583    }
5584
5585    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5586        Some(&self.excerpt(excerpt_id)?.buffer)
5587    }
5588
5589    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5590        let mut cursor = self
5591            .excerpts
5592            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
5593        let locator = self.excerpt_locator_for_id(excerpt_id);
5594        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
5595        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5596            sought_exact = true;
5597            cursor.prev();
5598        } else if excerpt_id == ExcerptId::min() {
5599            sought_exact = true;
5600        }
5601        if sought_exact {
5602            let start = cursor.start().1.clone();
5603            let end = cursor.end().1;
5604            let mut diff_transforms = self
5605                .diff_transforms
5606                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
5607            diff_transforms.seek(&start, Bias::Left);
5608            let overshoot = start.0 - diff_transforms.start().0.0;
5609            let start = diff_transforms.start().1.0 + overshoot;
5610            diff_transforms.seek(&end, Bias::Right);
5611            let overshoot = end.0 - diff_transforms.start().0.0;
5612            let end = diff_transforms.start().1.0 + overshoot;
5613            Some(start..end)
5614        } else {
5615            None
5616        }
5617    }
5618
5619    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5620        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5621        let locator = self.excerpt_locator_for_id(excerpt_id);
5622        cursor.seek(&Some(locator), Bias::Left);
5623        if let Some(excerpt) = cursor.item()
5624            && excerpt.id == excerpt_id
5625        {
5626            return Some(excerpt);
5627        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5628            cursor.prev();
5629            return cursor.item();
5630        }
5631        None
5632    }
5633
5634    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5635    pub fn excerpt_containing<T: ToOffset>(
5636        &self,
5637        range: Range<T>,
5638    ) -> Option<MultiBufferExcerpt<'_>> {
5639        let range = range.start.to_offset(self)..range.end.to_offset(self);
5640        let mut cursor = self.cursor::<usize>();
5641        cursor.seek(&range.start);
5642
5643        let start_excerpt = cursor.excerpt()?;
5644        if range.end != range.start {
5645            cursor.seek_forward(&range.end);
5646            if cursor.excerpt()?.id != start_excerpt.id {
5647                return None;
5648            }
5649        }
5650
5651        cursor.seek_to_start_of_current_excerpt();
5652        let region = cursor.region()?;
5653        let offset = region.range.start;
5654        let buffer_offset = start_excerpt.buffer_start_offset();
5655        let excerpt_offset = cursor.excerpts.start().clone();
5656        Some(MultiBufferExcerpt {
5657            diff_transforms: cursor.diff_transforms,
5658            excerpt: start_excerpt,
5659            offset,
5660            buffer_offset,
5661            excerpt_offset,
5662        })
5663    }
5664
5665    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
5666        if let Some(id) = anchor.buffer_id {
5667            return Some(id);
5668        }
5669        let excerpt = self.excerpt_containing(anchor..anchor)?;
5670        Some(excerpt.buffer_id())
5671    }
5672
5673    pub fn selections_in_range<'a>(
5674        &'a self,
5675        range: &'a Range<Anchor>,
5676        include_local: bool,
5677    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5678        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5679        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5680        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5681        cursor.seek(start_locator, Bias::Left);
5682        cursor
5683            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5684            .flat_map(move |excerpt| {
5685                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5686                if excerpt.id == range.start.excerpt_id {
5687                    query_range.start = range.start.text_anchor;
5688                }
5689                if excerpt.id == range.end.excerpt_id {
5690                    query_range.end = range.end.text_anchor;
5691                }
5692
5693                excerpt
5694                    .buffer
5695                    .selections_in_range(query_range, include_local)
5696                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5697                        selections.map(move |selection| {
5698                            let mut start =
5699                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.start);
5700                            let mut end =
5701                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.end);
5702                            if range.start.cmp(&start, self).is_gt() {
5703                                start = range.start;
5704                            }
5705                            if range.end.cmp(&end, self).is_lt() {
5706                                end = range.end;
5707                            }
5708
5709                            (
5710                                replica_id,
5711                                line_mode,
5712                                cursor_shape,
5713                                Selection {
5714                                    id: selection.id,
5715                                    start,
5716                                    end,
5717                                    reversed: selection.reversed,
5718                                    goal: selection.goal,
5719                                },
5720                            )
5721                        })
5722                    })
5723            })
5724    }
5725
5726    pub fn show_headers(&self) -> bool {
5727        self.show_headers
5728    }
5729
5730    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5731        self.diffs.get(&buffer_id)
5732    }
5733
5734    /// Visually annotates a position or range with the `Debug` representation of a value. The
5735    /// callsite of this function is used as a key - previous annotations will be removed.
5736    #[cfg(debug_assertions)]
5737    #[track_caller]
5738    pub fn debug<V, R>(&self, ranges: &R, value: V)
5739    where
5740        R: debug::ToMultiBufferDebugRanges,
5741        V: std::fmt::Debug,
5742    {
5743        self.debug_with_key(std::panic::Location::caller(), ranges, value);
5744    }
5745
5746    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
5747    /// debug annotations with the same key will be removed. The key is also used to determine the
5748    /// annotation's color.
5749    #[cfg(debug_assertions)]
5750    #[track_caller]
5751    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
5752    where
5753        K: std::hash::Hash + 'static,
5754        R: debug::ToMultiBufferDebugRanges,
5755        V: std::fmt::Debug,
5756    {
5757        let text_ranges = ranges
5758            .to_multi_buffer_debug_ranges(self)
5759            .into_iter()
5760            .flat_map(|range| {
5761                self.range_to_buffer_ranges(range).into_iter().map(
5762                    |(buffer, range, _excerpt_id)| {
5763                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
5764                    },
5765                )
5766            })
5767            .collect();
5768        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
5769            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
5770        });
5771    }
5772}
5773
5774#[cfg(any(test, feature = "test-support"))]
5775impl MultiBufferSnapshot {
5776    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5777        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
5778        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
5779        start..end
5780    }
5781
5782    #[cfg(any(test, feature = "test-support"))]
5783    fn check_invariants(&self) {
5784        let excerpts = self.excerpts.items(());
5785        let excerpt_ids = self.excerpt_ids.items(());
5786
5787        for (ix, excerpt) in excerpts.iter().enumerate() {
5788            if ix == 0 {
5789                if excerpt.locator <= Locator::min() {
5790                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5791                }
5792            } else if excerpt.locator <= excerpts[ix - 1].locator {
5793                panic!("excerpts are out-of-order: {:?}", excerpts);
5794            }
5795        }
5796
5797        for (ix, entry) in excerpt_ids.iter().enumerate() {
5798            if ix == 0 {
5799                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
5800                    panic!("invalid first excerpt id {:?}", entry.id);
5801                }
5802            } else if entry.id <= excerpt_ids[ix - 1].id {
5803                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5804            }
5805        }
5806
5807        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5808            panic!(
5809                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5810                self.excerpts.summary().text.len,
5811                self.diff_transforms.summary().input,
5812                self.diff_transforms.items(()),
5813            );
5814        }
5815
5816        let mut prev_transform: Option<&DiffTransform> = None;
5817        for item in self.diff_transforms.iter() {
5818            if let DiffTransform::BufferContent {
5819                summary,
5820                inserted_hunk_info,
5821            } = item
5822            {
5823                if let Some(DiffTransform::BufferContent {
5824                    inserted_hunk_info: prev_inserted_hunk_info,
5825                    ..
5826                }) = prev_transform
5827                    && *inserted_hunk_info == *prev_inserted_hunk_info
5828                {
5829                    panic!(
5830                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
5831                        self.diff_transforms.items(())
5832                    );
5833                }
5834                if summary.len == 0 && !self.is_empty() {
5835                    panic!("empty buffer content transform");
5836                }
5837            }
5838            prev_transform = Some(item);
5839        }
5840    }
5841}
5842
5843impl<'a, D> MultiBufferCursor<'a, D>
5844where
5845    D: TextDimension + Ord + Sub<D, Output = D>,
5846{
5847    fn seek(&mut self, position: &D) {
5848        self.cached_region.take();
5849        self.diff_transforms
5850            .seek(&OutputDimension(*position), Bias::Right);
5851        if self.diff_transforms.item().is_none()
5852            && *position == self.diff_transforms.start().output_dimension.0
5853        {
5854            self.diff_transforms.prev();
5855        }
5856
5857        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5858        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5859            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5860            excerpt_position.add_assign(&overshoot);
5861        }
5862
5863        self.excerpts
5864            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
5865        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5866            self.excerpts.prev();
5867        }
5868    }
5869
5870    fn seek_forward(&mut self, position: &D) {
5871        self.cached_region.take();
5872        self.diff_transforms
5873            .seek_forward(&OutputDimension(*position), Bias::Right);
5874        if self.diff_transforms.item().is_none()
5875            && *position == self.diff_transforms.start().output_dimension.0
5876        {
5877            self.diff_transforms.prev();
5878        }
5879
5880        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5881        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5882        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5883            excerpt_position.add_assign(&overshoot);
5884        }
5885
5886        self.excerpts
5887            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
5888        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5889            self.excerpts.prev();
5890        }
5891    }
5892
5893    fn next_excerpt(&mut self) {
5894        self.excerpts.next();
5895        self.seek_to_start_of_current_excerpt();
5896    }
5897
5898    fn prev_excerpt(&mut self) {
5899        self.excerpts.prev();
5900        self.seek_to_start_of_current_excerpt();
5901    }
5902
5903    fn seek_to_start_of_current_excerpt(&mut self) {
5904        self.cached_region.take();
5905        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
5906        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
5907            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
5908            && self.diff_transforms.next_item().is_some()
5909        {
5910            self.diff_transforms.next();
5911        }
5912    }
5913
5914    fn next(&mut self) {
5915        self.cached_region.take();
5916        match self
5917            .diff_transforms
5918            .end()
5919            .excerpt_dimension
5920            .cmp(&self.excerpts.end())
5921        {
5922            cmp::Ordering::Less => self.diff_transforms.next(),
5923            cmp::Ordering::Greater => self.excerpts.next(),
5924            cmp::Ordering::Equal => {
5925                self.diff_transforms.next();
5926                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
5927                    || self.diff_transforms.item().is_none()
5928                {
5929                    self.excerpts.next();
5930                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
5931                    self.diff_transforms.item()
5932                    && self
5933                        .excerpts
5934                        .item()
5935                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
5936                {
5937                    self.excerpts.next();
5938                }
5939            }
5940        }
5941    }
5942
5943    fn prev(&mut self) {
5944        self.cached_region.take();
5945        match self
5946            .diff_transforms
5947            .start()
5948            .excerpt_dimension
5949            .cmp(self.excerpts.start())
5950        {
5951            cmp::Ordering::Less => self.excerpts.prev(),
5952            cmp::Ordering::Greater => self.diff_transforms.prev(),
5953            cmp::Ordering::Equal => {
5954                self.diff_transforms.prev();
5955                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
5956                    || self.diff_transforms.item().is_none()
5957                {
5958                    self.excerpts.prev();
5959                }
5960            }
5961        }
5962    }
5963
5964    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
5965        if self.cached_region.is_none() {
5966            self.cached_region = self.build_region();
5967        }
5968        self.cached_region.clone()
5969    }
5970
5971    fn is_at_start_of_excerpt(&mut self) -> bool {
5972        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
5973            return false;
5974        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
5975            return true;
5976        }
5977
5978        self.diff_transforms.prev();
5979        let prev_transform = self.diff_transforms.item();
5980        self.diff_transforms.next();
5981
5982        prev_transform.is_none_or(|next_transform| {
5983            matches!(next_transform, DiffTransform::BufferContent { .. })
5984        })
5985    }
5986
5987    fn is_at_end_of_excerpt(&mut self) -> bool {
5988        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
5989            return false;
5990        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
5991            || self.diff_transforms.item().is_none()
5992        {
5993            return true;
5994        }
5995
5996        let next_transform = self.diff_transforms.next_item();
5997        next_transform.is_none_or(|next_transform| match next_transform {
5998            DiffTransform::BufferContent { .. } => true,
5999            DiffTransform::DeletedHunk { hunk_info, .. } => self
6000                .excerpts
6001                .item()
6002                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6003        })
6004    }
6005
6006    fn main_buffer_position(&self) -> Option<D> {
6007        let excerpt = self.excerpts.item()?;
6008        let buffer = &excerpt.buffer;
6009        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6010        let mut buffer_start = buffer_context_start;
6011        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6012        buffer_start.add_assign(&overshoot);
6013        Some(buffer_start)
6014    }
6015
6016    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6017        let excerpt = self.excerpts.item()?;
6018        match self.diff_transforms.item()? {
6019            DiffTransform::DeletedHunk {
6020                buffer_id,
6021                base_text_byte_range,
6022                has_trailing_newline,
6023                hunk_info,
6024                ..
6025            } => {
6026                let diff = self.diffs.get(buffer_id)?;
6027                let buffer = diff.base_text();
6028                let mut rope_cursor = buffer.as_rope().cursor(0);
6029                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6030                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6031                let mut buffer_end = buffer_start;
6032                buffer_end.add_assign(&buffer_range_len);
6033                let start = self.diff_transforms.start().output_dimension.0;
6034                let end = self.diff_transforms.end().output_dimension.0;
6035                Some(MultiBufferRegion {
6036                    buffer,
6037                    excerpt,
6038                    has_trailing_newline: *has_trailing_newline,
6039                    is_main_buffer: false,
6040                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6041                        hunk_info.hunk_secondary_status,
6042                    )),
6043                    buffer_range: buffer_start..buffer_end,
6044                    range: start..end,
6045                })
6046            }
6047            DiffTransform::BufferContent {
6048                inserted_hunk_info, ..
6049            } => {
6050                let buffer = &excerpt.buffer;
6051                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6052
6053                let mut start = self.diff_transforms.start().output_dimension.0;
6054                let mut buffer_start = buffer_context_start;
6055                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6056                    let overshoot =
6057                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6058                    start.add_assign(&overshoot);
6059                } else {
6060                    let overshoot =
6061                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6062                    buffer_start.add_assign(&overshoot);
6063                }
6064
6065                let mut end;
6066                let mut buffer_end;
6067                let has_trailing_newline;
6068                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6069                    let overshoot =
6070                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6071                    end = self.diff_transforms.end().output_dimension.0;
6072                    buffer_end = buffer_context_start;
6073                    buffer_end.add_assign(&overshoot);
6074                    has_trailing_newline = false;
6075                } else {
6076                    let overshoot =
6077                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6078                    end = self.diff_transforms.start().output_dimension.0;
6079                    end.add_assign(&overshoot);
6080                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6081                    has_trailing_newline = excerpt.has_trailing_newline;
6082                };
6083
6084                Some(MultiBufferRegion {
6085                    buffer,
6086                    excerpt,
6087                    has_trailing_newline,
6088                    is_main_buffer: true,
6089                    diff_hunk_status: inserted_hunk_info
6090                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6091                    buffer_range: buffer_start..buffer_end,
6092                    range: start..end,
6093                })
6094            }
6095        }
6096    }
6097
6098    fn excerpt(&self) -> Option<&'a Excerpt> {
6099        self.excerpts.item()
6100    }
6101}
6102
6103impl Excerpt {
6104    fn new(
6105        id: ExcerptId,
6106        locator: Locator,
6107        buffer_id: BufferId,
6108        buffer: BufferSnapshot,
6109        range: ExcerptRange<text::Anchor>,
6110        has_trailing_newline: bool,
6111    ) -> Self {
6112        Excerpt {
6113            id,
6114            locator,
6115            max_buffer_row: range.context.end.to_point(&buffer).row,
6116            text_summary: buffer
6117                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6118            buffer_id,
6119            buffer,
6120            range,
6121            has_trailing_newline,
6122        }
6123    }
6124
6125    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6126        let content_start = self.range.context.start.to_offset(&self.buffer);
6127        let chunks_start = content_start + range.start;
6128        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6129
6130        let has_footer = self.has_trailing_newline
6131            && range.start <= self.text_summary.len
6132            && range.end > self.text_summary.len;
6133
6134        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6135
6136        ExcerptChunks {
6137            excerpt_id: self.id,
6138            content_chunks,
6139            has_footer,
6140        }
6141    }
6142
6143    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6144        let content_start = self.range.context.start.to_offset(&self.buffer);
6145        let chunks_start = content_start + range.start;
6146        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6147        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6148        excerpt_chunks.has_footer = self.has_trailing_newline
6149            && range.start <= self.text_summary.len
6150            && range.end > self.text_summary.len;
6151    }
6152
6153    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6154        if text_anchor
6155            .cmp(&self.range.context.start, &self.buffer)
6156            .is_lt()
6157        {
6158            self.range.context.start
6159        } else if text_anchor
6160            .cmp(&self.range.context.end, &self.buffer)
6161            .is_gt()
6162        {
6163            self.range.context.end
6164        } else {
6165            text_anchor
6166        }
6167    }
6168
6169    fn contains(&self, anchor: &Anchor) -> bool {
6170        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
6171            && self
6172                .range
6173                .context
6174                .start
6175                .cmp(&anchor.text_anchor, &self.buffer)
6176                .is_le()
6177            && self
6178                .range
6179                .context
6180                .end
6181                .cmp(&anchor.text_anchor, &self.buffer)
6182                .is_ge()
6183    }
6184
6185    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6186    fn buffer_start_offset(&self) -> usize {
6187        self.range.context.start.to_offset(&self.buffer)
6188    }
6189
6190    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6191    fn buffer_end_offset(&self) -> usize {
6192        self.buffer_start_offset() + self.text_summary.len
6193    }
6194}
6195
6196impl<'a> MultiBufferExcerpt<'a> {
6197    pub fn id(&self) -> ExcerptId {
6198        self.excerpt.id
6199    }
6200
6201    pub fn buffer_id(&self) -> BufferId {
6202        self.excerpt.buffer_id
6203    }
6204
6205    pub fn start_anchor(&self) -> Anchor {
6206        Anchor::in_buffer(
6207            self.excerpt.id,
6208            self.excerpt.buffer_id,
6209            self.excerpt.range.context.start,
6210        )
6211    }
6212
6213    pub fn end_anchor(&self) -> Anchor {
6214        Anchor::in_buffer(
6215            self.excerpt.id,
6216            self.excerpt.buffer_id,
6217            self.excerpt.range.context.end,
6218        )
6219    }
6220
6221    pub fn buffer(&self) -> &'a BufferSnapshot {
6222        &self.excerpt.buffer
6223    }
6224
6225    pub fn buffer_range(&self) -> Range<usize> {
6226        self.buffer_offset
6227            ..self
6228                .excerpt
6229                .range
6230                .context
6231                .end
6232                .to_offset(&self.excerpt.buffer.text)
6233    }
6234
6235    pub fn start_offset(&self) -> usize {
6236        self.offset
6237    }
6238
6239    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6240    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6241        self.map_range_to_buffer(offset..offset).start
6242    }
6243
6244    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6245    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6246        self.diff_transforms
6247            .seek(&OutputDimension(range.start), Bias::Right);
6248        let start = self.map_offset_to_buffer_internal(range.start);
6249        let end = if range.end > range.start {
6250            self.diff_transforms
6251                .seek_forward(&OutputDimension(range.end), Bias::Right);
6252            self.map_offset_to_buffer_internal(range.end)
6253        } else {
6254            start
6255        };
6256        start..end
6257    }
6258
6259    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6260        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
6261        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6262            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
6263        };
6264        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6265        self.buffer_offset + offset_in_excerpt
6266    }
6267
6268    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6269    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6270        self.map_range_from_buffer(buffer_offset..buffer_offset)
6271            .start
6272    }
6273
6274    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6275    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6276        if buffer_range.start < self.buffer_offset {
6277            log::warn!(
6278                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6279            );
6280            return buffer_range;
6281        }
6282        let overshoot = buffer_range.start - self.buffer_offset;
6283        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6284        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
6285        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
6286            log::warn!(
6287                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6288            );
6289            return buffer_range;
6290        }
6291        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6292        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
6293
6294        let end = if buffer_range.end > buffer_range.start {
6295            let overshoot = buffer_range.end - self.buffer_offset;
6296            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6297            self.diff_transforms
6298                .seek_forward(&excerpt_offset, Bias::Right);
6299            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6300            self.diff_transforms.start().output_dimension.0 + overshoot
6301        } else {
6302            start
6303        };
6304
6305        start..end
6306    }
6307
6308    /// Returns true if the entirety of the given range is in the buffer's excerpt
6309    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6310        range.start >= self.excerpt.buffer_start_offset()
6311            && range.end <= self.excerpt.buffer_end_offset()
6312    }
6313
6314    pub fn max_buffer_row(&self) -> u32 {
6315        self.excerpt.max_buffer_row
6316    }
6317}
6318
6319impl ExcerptId {
6320    pub fn min() -> Self {
6321        Self(0)
6322    }
6323
6324    pub fn max() -> Self {
6325        Self(u32::MAX)
6326    }
6327
6328    pub fn to_proto(self) -> u64 {
6329        self.0 as _
6330    }
6331
6332    pub fn from_proto(proto: u64) -> Self {
6333        Self(proto as _)
6334    }
6335
6336    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6337        let a = snapshot.excerpt_locator_for_id(*self);
6338        let b = snapshot.excerpt_locator_for_id(*other);
6339        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6340    }
6341}
6342
6343impl From<ExcerptId> for usize {
6344    fn from(val: ExcerptId) -> Self {
6345        val.0 as usize
6346    }
6347}
6348
6349impl fmt::Debug for Excerpt {
6350    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6351        f.debug_struct("Excerpt")
6352            .field("id", &self.id)
6353            .field("locator", &self.locator)
6354            .field("buffer_id", &self.buffer_id)
6355            .field("range", &self.range)
6356            .field("text_summary", &self.text_summary)
6357            .field("has_trailing_newline", &self.has_trailing_newline)
6358            .finish()
6359    }
6360}
6361
6362impl sum_tree::Item for Excerpt {
6363    type Summary = ExcerptSummary;
6364
6365    fn summary(&self, _cx: ()) -> Self::Summary {
6366        let mut text = self.text_summary;
6367        if self.has_trailing_newline {
6368            text += TextSummary::from("\n");
6369        }
6370        ExcerptSummary {
6371            excerpt_id: self.id,
6372            excerpt_locator: self.locator.clone(),
6373            widest_line_number: self.max_buffer_row,
6374            text,
6375        }
6376    }
6377}
6378
6379impl sum_tree::Item for ExcerptIdMapping {
6380    type Summary = ExcerptId;
6381
6382    fn summary(&self, _cx: ()) -> Self::Summary {
6383        self.id
6384    }
6385}
6386
6387impl sum_tree::KeyedItem for ExcerptIdMapping {
6388    type Key = ExcerptId;
6389
6390    fn key(&self) -> Self::Key {
6391        self.id
6392    }
6393}
6394
6395impl DiffTransform {
6396    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6397        match self {
6398            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6399            DiffTransform::BufferContent {
6400                inserted_hunk_info, ..
6401            } => *inserted_hunk_info,
6402        }
6403    }
6404}
6405
6406impl sum_tree::Item for DiffTransform {
6407    type Summary = DiffTransformSummary;
6408
6409    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
6410        match self {
6411            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6412                input: *summary,
6413                output: *summary,
6414            },
6415            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6416                input: TextSummary::default(),
6417                output: *summary,
6418            },
6419        }
6420    }
6421}
6422
6423impl DiffTransformSummary {
6424    fn excerpt_len(&self) -> ExcerptOffset {
6425        ExcerptOffset::new(self.input.len)
6426    }
6427}
6428
6429impl sum_tree::ContextLessSummary for DiffTransformSummary {
6430    fn zero() -> Self {
6431        DiffTransformSummary {
6432            input: TextSummary::default(),
6433            output: TextSummary::default(),
6434        }
6435    }
6436
6437    fn add_summary(&mut self, other: &Self) {
6438        self.input += other.input;
6439        self.output += other.output;
6440    }
6441}
6442
6443impl sum_tree::ContextLessSummary for ExcerptId {
6444    fn zero() -> Self {
6445        Self(0)
6446    }
6447
6448    fn add_summary(&mut self, summary: &Self) {
6449        *self = cmp::max(*self, *summary);
6450    }
6451}
6452
6453impl sum_tree::ContextLessSummary for ExcerptSummary {
6454    fn zero() -> Self {
6455        Self::default()
6456    }
6457
6458    fn add_summary(&mut self, summary: &Self) {
6459        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6460        self.excerpt_locator = summary.excerpt_locator.clone();
6461        Summary::add_summary(&mut self.text, &summary.text, ());
6462        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6463    }
6464}
6465
6466impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6467    fn zero(_cx: ()) -> Self {
6468        Default::default()
6469    }
6470
6471    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6472        self.value += summary.text.len;
6473    }
6474}
6475
6476impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6477    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6478        Ord::cmp(&self.value, &cursor_location.text.len)
6479    }
6480}
6481
6482impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6483    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
6484        Ord::cmp(&Some(self), cursor_location)
6485    }
6486}
6487
6488impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6489    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6490        Ord::cmp(self, &cursor_location.excerpt_locator)
6491    }
6492}
6493
6494impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6495    fn zero(_cx: ()) -> Self {
6496        Default::default()
6497    }
6498
6499    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6500        self.value += summary.text.lines;
6501    }
6502}
6503
6504impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6505    for ExcerptDimension<D>
6506{
6507    fn zero(_: ()) -> Self {
6508        ExcerptDimension(D::default())
6509    }
6510
6511    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6512        self.0.add_assign(&D::from_text_summary(&summary.text))
6513    }
6514}
6515
6516impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6517    fn zero(_cx: ()) -> Self {
6518        Default::default()
6519    }
6520
6521    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6522        *self = Some(&summary.excerpt_locator);
6523    }
6524}
6525
6526impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6527    fn zero(_cx: ()) -> Self {
6528        Default::default()
6529    }
6530
6531    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6532        *self = Some(summary.excerpt_id);
6533    }
6534}
6535
6536#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6537struct ExcerptDimension<T>(T);
6538
6539#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6540struct OutputDimension<T>(T);
6541
6542impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6543    fn zero(_: ()) -> Self {
6544        ExcerptOffset::new(0)
6545    }
6546
6547    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6548        self.value += summary.input.len;
6549    }
6550}
6551
6552impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6553    fn zero(_: ()) -> Self {
6554        ExcerptPoint::new(0, 0)
6555    }
6556
6557    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6558        self.value += summary.input.lines;
6559    }
6560}
6561
6562impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6563    for ExcerptDimension<D>
6564{
6565    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
6566        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6567    }
6568}
6569
6570impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6571    for ExcerptDimension<D>
6572{
6573    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6574        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
6575    }
6576}
6577
6578impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6579    fn zero(_: ()) -> Self {
6580        ExcerptDimension(D::default())
6581    }
6582
6583    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6584        self.0.add_assign(&D::from_text_summary(&summary.input))
6585    }
6586}
6587
6588impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6589    for OutputDimension<D>
6590{
6591    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6592        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
6593    }
6594}
6595
6596impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6597    fn zero(_: ()) -> Self {
6598        OutputDimension(D::default())
6599    }
6600
6601    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6602        self.0.add_assign(&D::from_text_summary(&summary.output))
6603    }
6604}
6605
6606impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6607    fn zero(_: ()) -> Self {
6608        TextSummary::default()
6609    }
6610
6611    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6612        *self += summary.output
6613    }
6614}
6615
6616impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6617    fn zero(_: ()) -> Self {
6618        0
6619    }
6620
6621    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6622        *self += summary.output.len
6623    }
6624}
6625
6626impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6627    fn zero(_: ()) -> Self {
6628        Point::new(0, 0)
6629    }
6630
6631    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6632        *self += summary.output.lines
6633    }
6634}
6635
6636impl MultiBufferRows<'_> {
6637    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6638        self.point = Point::new(row, 0);
6639        self.cursor.seek(&self.point);
6640    }
6641}
6642
6643impl Iterator for MultiBufferRows<'_> {
6644    type Item = RowInfo;
6645
6646    fn next(&mut self) -> Option<Self::Item> {
6647        if self.is_empty && self.point.row == 0 {
6648            self.point += Point::new(1, 0);
6649            return Some(RowInfo {
6650                buffer_id: None,
6651                buffer_row: Some(0),
6652                multibuffer_row: Some(MultiBufferRow(0)),
6653                diff_status: None,
6654                expand_info: None,
6655            });
6656        }
6657
6658        let mut region = self.cursor.region()?;
6659        while self.point >= region.range.end {
6660            self.cursor.next();
6661            if let Some(next_region) = self.cursor.region() {
6662                region = next_region;
6663            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
6664                let multibuffer_row = MultiBufferRow(self.point.row);
6665                let last_excerpt = self
6666                    .cursor
6667                    .excerpts
6668                    .item()
6669                    .or(self.cursor.excerpts.prev_item())?;
6670                let last_row = last_excerpt
6671                    .range
6672                    .context
6673                    .end
6674                    .to_point(&last_excerpt.buffer)
6675                    .row;
6676
6677                let first_row = last_excerpt
6678                    .range
6679                    .context
6680                    .start
6681                    .to_point(&last_excerpt.buffer)
6682                    .row;
6683
6684                let expand_info = if self.is_singleton {
6685                    None
6686                } else {
6687                    let needs_expand_up = first_row == last_row
6688                        && last_row > 0
6689                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
6690                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
6691
6692                    if needs_expand_up && needs_expand_down {
6693                        Some(ExpandExcerptDirection::UpAndDown)
6694                    } else if needs_expand_up {
6695                        Some(ExpandExcerptDirection::Up)
6696                    } else if needs_expand_down {
6697                        Some(ExpandExcerptDirection::Down)
6698                    } else {
6699                        None
6700                    }
6701                    .map(|direction| ExpandInfo {
6702                        direction,
6703                        excerpt_id: last_excerpt.id,
6704                    })
6705                };
6706                self.point += Point::new(1, 0);
6707                return Some(RowInfo {
6708                    buffer_id: Some(last_excerpt.buffer_id),
6709                    buffer_row: Some(last_row),
6710                    multibuffer_row: Some(multibuffer_row),
6711                    diff_status: None,
6712                    expand_info,
6713                });
6714            } else {
6715                return None;
6716            };
6717        }
6718
6719        let overshoot = self.point - region.range.start;
6720        let buffer_point = region.buffer_range.start + overshoot;
6721        let expand_info = if self.is_singleton {
6722            None
6723        } else {
6724            let needs_expand_up = self.point.row == region.range.start.row
6725                && self.cursor.is_at_start_of_excerpt()
6726                && buffer_point.row > 0;
6727            let needs_expand_down = (region.excerpt.has_trailing_newline
6728                && self.point.row + 1 == region.range.end.row
6729                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
6730                && self.cursor.is_at_end_of_excerpt()
6731                && buffer_point.row < region.buffer.max_point().row;
6732
6733            if needs_expand_up && needs_expand_down {
6734                Some(ExpandExcerptDirection::UpAndDown)
6735            } else if needs_expand_up {
6736                Some(ExpandExcerptDirection::Up)
6737            } else if needs_expand_down {
6738                Some(ExpandExcerptDirection::Down)
6739            } else {
6740                None
6741            }
6742            .map(|direction| ExpandInfo {
6743                direction,
6744                excerpt_id: region.excerpt.id,
6745            })
6746        };
6747
6748        let result = Some(RowInfo {
6749            buffer_id: Some(region.buffer.remote_id()),
6750            buffer_row: Some(buffer_point.row),
6751            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6752            diff_status: region
6753                .diff_hunk_status
6754                .filter(|_| self.point < region.range.end),
6755            expand_info,
6756        });
6757        self.point += Point::new(1, 0);
6758        result
6759    }
6760}
6761
6762impl<'a> MultiBufferChunks<'a> {
6763    pub fn offset(&self) -> usize {
6764        self.range.start
6765    }
6766
6767    pub fn seek(&mut self, range: Range<usize>) {
6768        self.diff_transforms.seek(&range.end, Bias::Right);
6769        let mut excerpt_end = self.diff_transforms.start().1;
6770        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6771            let overshoot = range.end - self.diff_transforms.start().0;
6772            excerpt_end.value += overshoot;
6773        }
6774
6775        self.diff_transforms.seek(&range.start, Bias::Right);
6776        let mut excerpt_start = self.diff_transforms.start().1;
6777        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6778            let overshoot = range.start - self.diff_transforms.start().0;
6779            excerpt_start.value += overshoot;
6780        }
6781
6782        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
6783        self.buffer_chunk.take();
6784        self.range = range;
6785    }
6786
6787    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
6788        self.excerpt_offset_range = new_range.clone();
6789        self.excerpts.seek(&new_range.start, Bias::Right);
6790        if let Some(excerpt) = self.excerpts.item() {
6791            let excerpt_start = *self.excerpts.start();
6792            if let Some(excerpt_chunks) = self
6793                .excerpt_chunks
6794                .as_mut()
6795                .filter(|chunks| excerpt.id == chunks.excerpt_id)
6796            {
6797                excerpt.seek_chunks(
6798                    excerpt_chunks,
6799                    (self.excerpt_offset_range.start - excerpt_start).value
6800                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6801                );
6802            } else {
6803                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6804                    (self.excerpt_offset_range.start - excerpt_start).value
6805                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6806                    self.language_aware,
6807                ));
6808            }
6809        } else {
6810            self.excerpt_chunks = None;
6811        }
6812    }
6813
6814    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
6815        loop {
6816            if self.excerpt_offset_range.is_empty() {
6817                return None;
6818            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
6819                self.excerpt_offset_range.start.value += chunk.text.len();
6820                return Some(chunk);
6821            } else {
6822                self.excerpts.next();
6823                let excerpt = self.excerpts.item()?;
6824                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6825                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
6826                    self.language_aware,
6827                ));
6828            }
6829        }
6830    }
6831}
6832
6833impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
6834    type Item = &'a str;
6835
6836    fn next(&mut self) -> Option<Self::Item> {
6837        let mut region = self.cursor.region()?;
6838        if self.offset == region.range.start {
6839            self.cursor.prev();
6840            region = self.cursor.region()?;
6841            let start_overshoot = self.start.saturating_sub(region.range.start);
6842            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
6843                region.buffer_range.start + start_overshoot..region.buffer_range.end,
6844            ));
6845        }
6846
6847        if self.offset == region.range.end && region.has_trailing_newline {
6848            self.offset -= 1;
6849            Some("\n")
6850        } else {
6851            let chunk = self.current_chunks.as_mut().unwrap().next()?;
6852            self.offset -= chunk.len();
6853            Some(chunk)
6854        }
6855    }
6856}
6857
6858impl<'a> Iterator for MultiBufferChunks<'a> {
6859    type Item = Chunk<'a>;
6860
6861    fn next(&mut self) -> Option<Chunk<'a>> {
6862        if self.range.start >= self.range.end {
6863            return None;
6864        }
6865        if self.range.start == self.diff_transforms.end().0 {
6866            self.diff_transforms.next();
6867        }
6868
6869        let diff_transform_start = self.diff_transforms.start().0;
6870        let diff_transform_end = self.diff_transforms.end().0;
6871        debug_assert!(self.range.start < diff_transform_end);
6872
6873        let diff_transform = self.diff_transforms.item()?;
6874        match diff_transform {
6875            DiffTransform::BufferContent { .. } => {
6876                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
6877                    chunk
6878                } else {
6879                    let chunk = self.next_excerpt_chunk().unwrap();
6880                    self.buffer_chunk.insert(chunk)
6881                };
6882
6883                let chunk_end = self.range.start + chunk.text.len();
6884                let diff_transform_end = diff_transform_end.min(self.range.end);
6885
6886                if diff_transform_end < chunk_end {
6887                    let split_idx = diff_transform_end - self.range.start;
6888                    let (before, after) = chunk.text.split_at(split_idx);
6889                    self.range.start = diff_transform_end;
6890                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
6891                    let chars = chunk.chars & mask;
6892                    let tabs = chunk.tabs & mask;
6893
6894                    chunk.text = after;
6895                    chunk.chars = chunk.chars >> split_idx;
6896                    chunk.tabs = chunk.tabs >> split_idx;
6897
6898                    Some(Chunk {
6899                        text: before,
6900                        chars,
6901                        tabs,
6902                        ..chunk.clone()
6903                    })
6904                } else {
6905                    self.range.start = chunk_end;
6906                    self.buffer_chunk.take()
6907                }
6908            }
6909            DiffTransform::DeletedHunk {
6910                buffer_id,
6911                base_text_byte_range,
6912                has_trailing_newline,
6913                ..
6914            } => {
6915                let base_text_start =
6916                    base_text_byte_range.start + self.range.start - diff_transform_start;
6917                let base_text_end =
6918                    base_text_byte_range.start + self.range.end - diff_transform_start;
6919                let base_text_end = base_text_end.min(base_text_byte_range.end);
6920
6921                let mut chunks = if let Some((_, mut chunks)) = self
6922                    .diff_base_chunks
6923                    .take()
6924                    .filter(|(id, _)| id == buffer_id)
6925                {
6926                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
6927                    {
6928                        chunks.seek(base_text_start..base_text_end);
6929                    }
6930                    chunks
6931                } else {
6932                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
6933                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
6934                };
6935
6936                let chunk = if let Some(chunk) = chunks.next() {
6937                    self.range.start += chunk.text.len();
6938                    self.diff_base_chunks = Some((*buffer_id, chunks));
6939                    chunk
6940                } else {
6941                    debug_assert!(has_trailing_newline);
6942                    self.range.start += "\n".len();
6943                    Chunk {
6944                        text: "\n",
6945                        chars: 1u128,
6946                        ..Default::default()
6947                    }
6948                };
6949                Some(chunk)
6950            }
6951        }
6952    }
6953}
6954
6955impl MultiBufferBytes<'_> {
6956    fn consume(&mut self, len: usize) {
6957        self.range.start += len;
6958        self.chunk = &self.chunk[len..];
6959
6960        if !self.range.is_empty() && self.chunk.is_empty() {
6961            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
6962                self.chunk = chunk;
6963            } else if self.has_trailing_newline {
6964                self.has_trailing_newline = false;
6965                self.chunk = b"\n";
6966            } else {
6967                self.cursor.next();
6968                if let Some(region) = self.cursor.region() {
6969                    let mut excerpt_bytes = region.buffer.bytes_in_range(
6970                        region.buffer_range.start
6971                            ..(region.buffer_range.start + self.range.end - region.range.start)
6972                                .min(region.buffer_range.end),
6973                    );
6974                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
6975                    self.excerpt_bytes = Some(excerpt_bytes);
6976                    self.has_trailing_newline =
6977                        region.has_trailing_newline && self.range.end >= region.range.end;
6978                    if self.chunk.is_empty() && self.has_trailing_newline {
6979                        self.has_trailing_newline = false;
6980                        self.chunk = b"\n";
6981                    }
6982                }
6983            }
6984        }
6985    }
6986}
6987
6988impl<'a> Iterator for MultiBufferBytes<'a> {
6989    type Item = &'a [u8];
6990
6991    fn next(&mut self) -> Option<Self::Item> {
6992        let chunk = self.chunk;
6993        if chunk.is_empty() {
6994            None
6995        } else {
6996            self.consume(chunk.len());
6997            Some(chunk)
6998        }
6999    }
7000}
7001
7002impl io::Read for MultiBufferBytes<'_> {
7003    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7004        let len = cmp::min(buf.len(), self.chunk.len());
7005        buf[..len].copy_from_slice(&self.chunk[..len]);
7006        if len > 0 {
7007            self.consume(len);
7008        }
7009        Ok(len)
7010    }
7011}
7012
7013impl io::Read for ReversedMultiBufferBytes<'_> {
7014    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7015        let len = cmp::min(buf.len(), self.chunk.len());
7016        buf[..len].copy_from_slice(&self.chunk[..len]);
7017        buf[..len].reverse();
7018        if len > 0 {
7019            self.range.end -= len;
7020            self.chunk = &self.chunk[..self.chunk.len() - len];
7021            if !self.range.is_empty()
7022                && self.chunk.is_empty()
7023                && let Some(chunk) = self.chunks.next()
7024            {
7025                self.chunk = chunk.as_bytes();
7026            }
7027        }
7028        Ok(len)
7029    }
7030}
7031
7032impl<'a> Iterator for ExcerptChunks<'a> {
7033    type Item = Chunk<'a>;
7034
7035    fn next(&mut self) -> Option<Self::Item> {
7036        if let Some(chunk) = self.content_chunks.next() {
7037            return Some(chunk);
7038        }
7039
7040        if self.has_footer {
7041            let text = "\n";
7042            let chars = 0b1;
7043            self.has_footer = false;
7044            return Some(Chunk {
7045                text,
7046                chars,
7047                ..Default::default()
7048            });
7049        }
7050
7051        None
7052    }
7053}
7054
7055impl ToOffset for Point {
7056    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7057        snapshot.point_to_offset(*self)
7058    }
7059    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7060        snapshot.point_to_offset_utf16(*self)
7061    }
7062}
7063
7064impl ToOffset for usize {
7065    #[track_caller]
7066    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7067        assert!(
7068            *self <= snapshot.len(),
7069            "offset {} is greater than the snapshot.len() {}",
7070            *self,
7071            snapshot.len(),
7072        );
7073        *self
7074    }
7075    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7076        snapshot.offset_to_offset_utf16(*self)
7077    }
7078}
7079
7080impl ToOffset for OffsetUtf16 {
7081    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7082        snapshot.offset_utf16_to_offset(*self)
7083    }
7084
7085    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7086        *self
7087    }
7088}
7089
7090impl ToOffset for PointUtf16 {
7091    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7092        snapshot.point_utf16_to_offset(*self)
7093    }
7094    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7095        snapshot.point_utf16_to_offset_utf16(*self)
7096    }
7097}
7098
7099impl ToPoint for usize {
7100    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7101        snapshot.offset_to_point(*self)
7102    }
7103    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7104        snapshot.offset_to_point_utf16(*self)
7105    }
7106}
7107
7108impl ToPoint for Point {
7109    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7110        *self
7111    }
7112    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7113        snapshot.point_to_point_utf16(*self)
7114    }
7115}
7116
7117impl ToPoint for PointUtf16 {
7118    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7119        snapshot.point_utf16_to_point(*self)
7120    }
7121    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7122        *self
7123    }
7124}
7125
7126impl From<ExcerptId> for EntityId {
7127    fn from(id: ExcerptId) -> Self {
7128        EntityId::from(id.0 as u64)
7129    }
7130}
7131
7132#[cfg(debug_assertions)]
7133pub mod debug {
7134    use super::*;
7135
7136    pub trait ToMultiBufferDebugRanges {
7137        fn to_multi_buffer_debug_ranges(&self, snapshot: &MultiBufferSnapshot)
7138        -> Vec<Range<usize>>;
7139    }
7140
7141    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
7142        fn to_multi_buffer_debug_ranges(
7143            &self,
7144            snapshot: &MultiBufferSnapshot,
7145        ) -> Vec<Range<usize>> {
7146            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
7147        }
7148    }
7149
7150    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
7151        fn to_multi_buffer_debug_ranges(
7152            &self,
7153            snapshot: &MultiBufferSnapshot,
7154        ) -> Vec<Range<usize>> {
7155            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
7156                .to_multi_buffer_debug_ranges(snapshot)
7157        }
7158    }
7159
7160    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
7161        fn to_multi_buffer_debug_ranges(
7162            &self,
7163            snapshot: &MultiBufferSnapshot,
7164        ) -> Vec<Range<usize>> {
7165            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7166        }
7167    }
7168
7169    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
7170        fn to_multi_buffer_debug_ranges(
7171            &self,
7172            snapshot: &MultiBufferSnapshot,
7173        ) -> Vec<Range<usize>> {
7174            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7175        }
7176    }
7177
7178    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
7179        fn to_multi_buffer_debug_ranges(
7180            &self,
7181            snapshot: &MultiBufferSnapshot,
7182        ) -> Vec<Range<usize>> {
7183            self.iter()
7184                .map(|item| {
7185                    let offset = item.to_offset(snapshot);
7186                    offset..offset
7187                })
7188                .collect()
7189        }
7190    }
7191
7192    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
7193        fn to_multi_buffer_debug_ranges(
7194            &self,
7195            snapshot: &MultiBufferSnapshot,
7196        ) -> Vec<Range<usize>> {
7197            self.iter()
7198                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
7199                .collect()
7200        }
7201    }
7202}