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 remove_excerpts(
1544        &mut self,
1545        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1546        cx: &mut Context<Self>,
1547    ) {
1548        self.sync_mut(cx);
1549        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1550        if ids.is_empty() {
1551            return;
1552        }
1553        self.buffer_changed_since_sync.replace(true);
1554
1555        let mut snapshot = self.snapshot.get_mut();
1556        let mut new_excerpts = SumTree::default();
1557        let mut cursor = snapshot
1558            .excerpts
1559            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1560        let mut edits = Vec::new();
1561        let mut excerpt_ids = ids.iter().copied().peekable();
1562        let mut removed_buffer_ids = Vec::new();
1563
1564        while let Some(excerpt_id) = excerpt_ids.next() {
1565            self.paths_by_excerpt.remove(&excerpt_id);
1566            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1567            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1568            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
1569
1570            if let Some(mut excerpt) = cursor.item() {
1571                if excerpt.id != excerpt_id {
1572                    continue;
1573                }
1574                let mut old_start = cursor.start().1;
1575
1576                // Skip over the removed excerpt.
1577                'remove_excerpts: loop {
1578                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
1579                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1580                        if buffer_state.excerpts.is_empty() {
1581                            log::debug!(
1582                                "removing buffer and diff for buffer {}",
1583                                excerpt.buffer_id
1584                            );
1585                            self.buffers.remove(&excerpt.buffer_id);
1586                            removed_buffer_ids.push(excerpt.buffer_id);
1587                        }
1588                    }
1589                    cursor.next();
1590
1591                    // Skip over any subsequent excerpts that are also removed.
1592                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1593                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1594                        if let Some(next_excerpt) = cursor.item()
1595                            && next_excerpt.locator == *next_locator
1596                        {
1597                            excerpt_ids.next();
1598                            excerpt = next_excerpt;
1599                            continue 'remove_excerpts;
1600                        }
1601                    }
1602
1603                    break;
1604                }
1605
1606                // When removing the last excerpt, remove the trailing newline from
1607                // the previous excerpt.
1608                if cursor.item().is_none() && old_start.value > 0 {
1609                    old_start.value -= 1;
1610                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
1611                }
1612
1613                // Push an edit for the removal of this run of excerpts.
1614                let old_end = cursor.start().1;
1615                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1616                edits.push(Edit {
1617                    old: old_start..old_end,
1618                    new: new_start..new_start,
1619                });
1620            }
1621        }
1622        let suffix = cursor.suffix();
1623        let changed_trailing_excerpt = suffix.is_empty();
1624        new_excerpts.append(suffix, ());
1625        drop(cursor);
1626        snapshot.excerpts = new_excerpts;
1627        for buffer_id in &removed_buffer_ids {
1628            self.diffs.remove(buffer_id);
1629            snapshot.diffs.remove(buffer_id);
1630        }
1631
1632        if changed_trailing_excerpt {
1633            snapshot.trailing_excerpt_update_count += 1;
1634        }
1635
1636        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
1637        if !edits.is_empty() {
1638            self.subscriptions.publish(edits);
1639        }
1640        cx.emit(Event::Edited {
1641            edited_buffer: None,
1642        });
1643        cx.emit(Event::ExcerptsRemoved {
1644            ids,
1645            removed_buffer_ids,
1646        });
1647        cx.notify();
1648    }
1649
1650    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1651        &self,
1652        anchors: Anchors,
1653        cx: &mut Context<Self>,
1654    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1655        let mut error = None;
1656        let mut futures = Vec::new();
1657        for anchor in anchors {
1658            if let Some(buffer_id) = anchor.buffer_id {
1659                if let Some(buffer) = self.buffers.get(&buffer_id) {
1660                    buffer.buffer.update(cx, |buffer, _| {
1661                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1662                    });
1663                } else {
1664                    error = Some(anyhow!(
1665                        "buffer {buffer_id} is not part of this multi-buffer"
1666                    ));
1667                    break;
1668                }
1669            }
1670        }
1671        async move {
1672            if let Some(error) = error {
1673                Err(error)?;
1674            }
1675            for future in futures {
1676                future.await?;
1677            }
1678            Ok(())
1679        }
1680    }
1681
1682    pub fn text_anchor_for_position<T: ToOffset>(
1683        &self,
1684        position: T,
1685        cx: &App,
1686    ) -> Option<(Entity<Buffer>, language::Anchor)> {
1687        let snapshot = self.read(cx);
1688        let anchor = snapshot.anchor_before(position);
1689        let buffer = self.buffers.get(&anchor.buffer_id?)?.buffer.clone();
1690        Some((buffer, anchor.text_anchor))
1691    }
1692
1693    fn on_buffer_event(
1694        &mut self,
1695        buffer: Entity<Buffer>,
1696        event: &language::BufferEvent,
1697        cx: &mut Context<Self>,
1698    ) {
1699        use language::BufferEvent;
1700        cx.emit(match event {
1701            BufferEvent::Edited => Event::Edited {
1702                edited_buffer: Some(buffer),
1703            },
1704            BufferEvent::DirtyChanged => Event::DirtyChanged,
1705            BufferEvent::Saved => Event::Saved,
1706            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1707            BufferEvent::Reloaded => Event::Reloaded,
1708            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
1709            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
1710            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1711            BufferEvent::CapabilityChanged => {
1712                self.capability = buffer.read(cx).capability();
1713                return;
1714            }
1715            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1716        });
1717    }
1718
1719    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1720        let diff = diff.read(cx);
1721        let buffer_id = diff.buffer_id;
1722        let diff = diff.snapshot(cx);
1723        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
1724    }
1725
1726    fn buffer_diff_changed(
1727        &mut self,
1728        diff: Entity<BufferDiff>,
1729        range: Range<text::Anchor>,
1730        cx: &mut Context<Self>,
1731    ) {
1732        self.sync_mut(cx);
1733
1734        let diff = diff.read(cx);
1735        let buffer_id = diff.buffer_id;
1736        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
1737            return;
1738        };
1739        self.buffer_changed_since_sync.replace(true);
1740
1741        let buffer = buffer_state.buffer.read(cx);
1742        let diff_change_range = range.to_offset(buffer);
1743
1744        let new_diff = diff.snapshot(cx);
1745        let mut snapshot = self.snapshot.get_mut();
1746        let base_text_changed = snapshot
1747            .diffs
1748            .get(&buffer_id)
1749            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
1750
1751        snapshot.diffs.insert(buffer_id, new_diff);
1752
1753        let mut excerpt_edits = Vec::new();
1754        for locator in &buffer_state.excerpts {
1755            let mut cursor = snapshot
1756                .excerpts
1757                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1758            cursor.seek_forward(&Some(locator), Bias::Left);
1759            if let Some(excerpt) = cursor.item()
1760                && excerpt.locator == *locator
1761            {
1762                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
1763                if diff_change_range.end < excerpt_buffer_range.start
1764                    || diff_change_range.start > excerpt_buffer_range.end
1765                {
1766                    continue;
1767                }
1768                let excerpt_start = cursor.start().1;
1769                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
1770                let diff_change_start_in_excerpt = ExcerptOffset::new(
1771                    diff_change_range
1772                        .start
1773                        .saturating_sub(excerpt_buffer_range.start),
1774                );
1775                let diff_change_end_in_excerpt = ExcerptOffset::new(
1776                    diff_change_range
1777                        .end
1778                        .saturating_sub(excerpt_buffer_range.start),
1779                );
1780                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
1781                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
1782                excerpt_edits.push(Edit {
1783                    old: edit_start..edit_end,
1784                    new: edit_start..edit_end,
1785                });
1786            }
1787        }
1788
1789        let edits = Self::sync_diff_transforms(
1790            &mut snapshot,
1791            excerpt_edits,
1792            DiffChangeKind::DiffUpdated {
1793                base_changed: base_text_changed,
1794            },
1795        );
1796        if !edits.is_empty() {
1797            self.subscriptions.publish(edits);
1798        }
1799        cx.emit(Event::Edited {
1800            edited_buffer: None,
1801        });
1802    }
1803
1804    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
1805        self.buffers
1806            .values()
1807            .map(|state| state.buffer.clone())
1808            .collect()
1809    }
1810
1811    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
1812        self.buffers.keys().copied().collect()
1813    }
1814
1815    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
1816        self.buffers
1817            .get(&buffer_id)
1818            .map(|state| state.buffer.clone())
1819    }
1820
1821    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
1822        self.point_to_buffer_offset(point, cx)
1823            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
1824    }
1825
1826    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
1827        let buffer_id = self
1828            .snapshot
1829            .borrow()
1830            .excerpts
1831            .first()
1832            .map(|excerpt| excerpt.buffer.remote_id());
1833        buffer_id
1834            .and_then(|buffer_id| self.buffer(buffer_id))
1835            .map(|buffer| {
1836                let buffer = buffer.read(cx);
1837                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
1838            })
1839            .unwrap_or_else(move || self.language_settings_at(0, cx))
1840    }
1841
1842    pub fn language_settings_at<'a, T: ToOffset>(
1843        &'a self,
1844        point: T,
1845        cx: &'a App,
1846    ) -> Cow<'a, LanguageSettings> {
1847        let mut language = None;
1848        let mut file = None;
1849        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
1850            let buffer = buffer.read(cx);
1851            language = buffer.language_at(offset);
1852            file = buffer.file();
1853        }
1854        language_settings(language.map(|l| l.name()), file, cx)
1855    }
1856
1857    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
1858        self.buffers.values().for_each(|state| f(&state.buffer))
1859    }
1860
1861    pub fn explicit_title(&self) -> Option<&str> {
1862        self.title.as_deref()
1863    }
1864
1865    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
1866        if let Some(title) = self.title.as_ref() {
1867            return title.into();
1868        }
1869
1870        if let Some(buffer) = self.as_singleton() {
1871            let buffer = buffer.read(cx);
1872
1873            if let Some(file) = buffer.file() {
1874                return file.file_name(cx).into();
1875            }
1876
1877            if let Some(title) = self.buffer_content_title(buffer) {
1878                return title;
1879            }
1880        };
1881
1882        "untitled".into()
1883    }
1884
1885    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
1886        let mut is_leading_whitespace = true;
1887        let mut count = 0;
1888        let mut prev_was_space = false;
1889        let mut title = String::new();
1890
1891        for ch in buffer.snapshot().chars() {
1892            if is_leading_whitespace && ch.is_whitespace() {
1893                continue;
1894            }
1895
1896            is_leading_whitespace = false;
1897
1898            if ch == '\n' || count >= 40 {
1899                break;
1900            }
1901
1902            if ch.is_whitespace() {
1903                if !prev_was_space {
1904                    title.push(' ');
1905                    count += 1;
1906                    prev_was_space = true;
1907                }
1908            } else {
1909                title.push(ch);
1910                count += 1;
1911                prev_was_space = false;
1912            }
1913        }
1914
1915        let title = title.trim_end().to_string();
1916
1917        if title.is_empty() {
1918            return None;
1919        }
1920
1921        Some(title.into())
1922    }
1923
1924    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
1925        self.title = Some(title);
1926        cx.notify();
1927    }
1928
1929    /// Preserve preview tabs containing this multibuffer until additional edits occur.
1930    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
1931        for buffer_state in self.buffers.values() {
1932            buffer_state
1933                .buffer
1934                .update(cx, |buffer, _cx| buffer.refresh_preview());
1935        }
1936    }
1937
1938    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
1939    pub fn preserve_preview(&self, cx: &App) -> bool {
1940        self.buffers
1941            .values()
1942            .all(|state| state.buffer.read(cx).preserve_preview())
1943    }
1944
1945    #[cfg(any(test, feature = "test-support"))]
1946    pub fn is_parsing(&self, cx: &App) -> bool {
1947        self.as_singleton().unwrap().read(cx).is_parsing()
1948    }
1949
1950    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1951        let buffer_id = diff.read(cx).buffer_id;
1952        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
1953        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
1954    }
1955
1956    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
1957        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
1958    }
1959
1960    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
1961        self.expand_or_collapse_diff_hunks(ranges, true, cx);
1962    }
1963
1964    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
1965        self.expand_or_collapse_diff_hunks(ranges, false, cx);
1966    }
1967
1968    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
1969        self.snapshot.get_mut().all_diff_hunks_expanded = true;
1970        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
1971    }
1972
1973    pub fn all_diff_hunks_expanded(&self) -> bool {
1974        self.snapshot.borrow().all_diff_hunks_expanded
1975    }
1976
1977    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
1978        self.snapshot.get_mut().all_diff_hunks_expanded = false;
1979        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
1980    }
1981
1982    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
1983        self.read(cx)
1984            .diff_hunks_in_range(Anchor::min()..Anchor::max())
1985            .nth(1)
1986            .is_some()
1987    }
1988
1989    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
1990        let snapshot = self.read(cx);
1991        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
1992        let offset_range = range.to_offset(&snapshot);
1993        cursor.seek(&offset_range.start, Bias::Left);
1994        while let Some(item) = cursor.item() {
1995            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
1996                break;
1997            }
1998            if item.hunk_info().is_some() {
1999                return true;
2000            }
2001            cursor.next();
2002        }
2003        false
2004    }
2005
2006    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2007        let snapshot = self.read(cx);
2008        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2009        for range in ranges {
2010            let range = range.to_point(&snapshot);
2011            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2012            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2013            let start = start.saturating_sub(1);
2014            let end = snapshot.len().min(end + 1);
2015            cursor.seek(&start, Bias::Right);
2016            while let Some(item) = cursor.item() {
2017                if *cursor.start() >= end {
2018                    break;
2019                }
2020                if item.hunk_info().is_some() {
2021                    return true;
2022                }
2023                cursor.next();
2024            }
2025        }
2026        false
2027    }
2028
2029    pub fn expand_or_collapse_diff_hunks_inner(
2030        &mut self,
2031        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2032        expand: bool,
2033        cx: &mut Context<Self>,
2034    ) {
2035        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2036            return;
2037        }
2038        self.sync_mut(cx);
2039        let mut snapshot = self.snapshot.get_mut();
2040        let mut excerpt_edits = Vec::new();
2041        let mut last_hunk_row = None;
2042        for (range, end_excerpt_id) in ranges {
2043            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2044                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2045                    continue;
2046                }
2047                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2048                    continue;
2049                }
2050                let start = Anchor::in_buffer(
2051                    diff_hunk.excerpt_id,
2052                    diff_hunk.buffer_id,
2053                    diff_hunk.buffer_range.start,
2054                );
2055                let end = Anchor::in_buffer(
2056                    diff_hunk.excerpt_id,
2057                    diff_hunk.buffer_id,
2058                    diff_hunk.buffer_range.end,
2059                );
2060                let start = snapshot.excerpt_offset_for_anchor(&start);
2061                let end = snapshot.excerpt_offset_for_anchor(&end);
2062                last_hunk_row = Some(diff_hunk.row_range.start);
2063                excerpt_edits.push(text::Edit {
2064                    old: start..end,
2065                    new: start..end,
2066                });
2067            }
2068        }
2069
2070        let edits = Self::sync_diff_transforms(
2071            &mut snapshot,
2072            excerpt_edits,
2073            DiffChangeKind::ExpandOrCollapseHunks { expand },
2074        );
2075        if !edits.is_empty() {
2076            self.subscriptions.publish(edits);
2077        }
2078        cx.emit(Event::DiffHunksToggled);
2079        cx.emit(Event::Edited {
2080            edited_buffer: None,
2081        });
2082    }
2083
2084    pub fn expand_or_collapse_diff_hunks(
2085        &mut self,
2086        ranges: Vec<Range<Anchor>>,
2087        expand: bool,
2088        cx: &mut Context<Self>,
2089    ) {
2090        let snapshot = self.snapshot.borrow().clone();
2091        let ranges = ranges.iter().map(move |range| {
2092            let end_excerpt_id = range.end.excerpt_id;
2093            let range = range.to_point(&snapshot);
2094            let mut peek_end = range.end;
2095            if range.end.row < snapshot.max_row().0 {
2096                peek_end = Point::new(range.end.row + 1, 0);
2097            };
2098            (range.start..peek_end, end_excerpt_id)
2099        });
2100        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2101    }
2102
2103    pub fn resize_excerpt(
2104        &mut self,
2105        id: ExcerptId,
2106        range: Range<text::Anchor>,
2107        cx: &mut Context<Self>,
2108    ) {
2109        self.sync_mut(cx);
2110
2111        let mut snapshot = self.snapshot.get_mut();
2112        let locator = snapshot.excerpt_locator_for_id(id);
2113        let mut new_excerpts = SumTree::default();
2114        let mut cursor = snapshot
2115            .excerpts
2116            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2117        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2118
2119        let prefix = cursor.slice(&Some(locator), Bias::Left);
2120        new_excerpts.append(prefix, ());
2121
2122        let mut excerpt = cursor.item().unwrap().clone();
2123        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2124
2125        excerpt.range.context.start = range.start;
2126        excerpt.range.context.end = range.end;
2127        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2128
2129        excerpt.text_summary = excerpt
2130            .buffer
2131            .text_summary_for_range(excerpt.range.context.clone());
2132
2133        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2134        let old_start_offset = cursor.start().1;
2135        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2136        let edit = Edit {
2137            old: old_start_offset..old_start_offset + old_text_len,
2138            new: new_start_offset..new_start_offset + new_text_len,
2139        };
2140
2141        if let Some(last_edit) = edits.last_mut() {
2142            if last_edit.old.end == edit.old.start {
2143                last_edit.old.end = edit.old.end;
2144                last_edit.new.end = edit.new.end;
2145            } else {
2146                edits.push(edit);
2147            }
2148        } else {
2149            edits.push(edit);
2150        }
2151
2152        new_excerpts.push(excerpt, ());
2153
2154        cursor.next();
2155
2156        new_excerpts.append(cursor.suffix(), ());
2157
2158        drop(cursor);
2159        snapshot.excerpts = new_excerpts;
2160
2161        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2162        if !edits.is_empty() {
2163            self.subscriptions.publish(edits);
2164        }
2165        cx.emit(Event::Edited {
2166            edited_buffer: None,
2167        });
2168        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2169        cx.notify();
2170    }
2171
2172    pub fn expand_excerpts(
2173        &mut self,
2174        ids: impl IntoIterator<Item = ExcerptId>,
2175        line_count: u32,
2176        direction: ExpandExcerptDirection,
2177        cx: &mut Context<Self>,
2178    ) {
2179        if line_count == 0 {
2180            return;
2181        }
2182        self.sync_mut(cx);
2183        if !self.excerpts_by_path.is_empty() {
2184            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2185            return;
2186        }
2187        let mut snapshot = self.snapshot.get_mut();
2188
2189        let ids = ids.into_iter().collect::<Vec<_>>();
2190        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2191        let mut new_excerpts = SumTree::default();
2192        let mut cursor = snapshot
2193            .excerpts
2194            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2195        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2196
2197        for locator in &locators {
2198            let prefix = cursor.slice(&Some(locator), Bias::Left);
2199            new_excerpts.append(prefix, ());
2200
2201            let mut excerpt = cursor.item().unwrap().clone();
2202            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2203
2204            let up_line_count = if direction.should_expand_up() {
2205                line_count
2206            } else {
2207                0
2208            };
2209
2210            let start_row = excerpt
2211                .range
2212                .context
2213                .start
2214                .to_point(&excerpt.buffer)
2215                .row
2216                .saturating_sub(up_line_count);
2217            let start_point = Point::new(start_row, 0);
2218            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2219
2220            let down_line_count = if direction.should_expand_down() {
2221                line_count
2222            } else {
2223                0
2224            };
2225
2226            let mut end_point = excerpt.buffer.clip_point(
2227                excerpt.range.context.end.to_point(&excerpt.buffer)
2228                    + Point::new(down_line_count, 0),
2229                Bias::Left,
2230            );
2231            end_point.column = excerpt.buffer.line_len(end_point.row);
2232            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2233            excerpt.max_buffer_row = end_point.row;
2234
2235            excerpt.text_summary = excerpt
2236                .buffer
2237                .text_summary_for_range(excerpt.range.context.clone());
2238
2239            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2240            let old_start_offset = cursor.start().1;
2241            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2242            let edit = Edit {
2243                old: old_start_offset..old_start_offset + old_text_len,
2244                new: new_start_offset..new_start_offset + new_text_len,
2245            };
2246
2247            if let Some(last_edit) = edits.last_mut() {
2248                if last_edit.old.end == edit.old.start {
2249                    last_edit.old.end = edit.old.end;
2250                    last_edit.new.end = edit.new.end;
2251                } else {
2252                    edits.push(edit);
2253                }
2254            } else {
2255                edits.push(edit);
2256            }
2257
2258            new_excerpts.push(excerpt, ());
2259
2260            cursor.next();
2261        }
2262
2263        new_excerpts.append(cursor.suffix(), ());
2264
2265        drop(cursor);
2266        snapshot.excerpts = new_excerpts;
2267
2268        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2269        if !edits.is_empty() {
2270            self.subscriptions.publish(edits);
2271        }
2272        cx.emit(Event::Edited {
2273            edited_buffer: None,
2274        });
2275        cx.emit(Event::ExcerptsExpanded { ids });
2276        cx.notify();
2277    }
2278
2279    fn sync(&self, cx: &App) {
2280        let changed = self.buffer_changed_since_sync.replace(false);
2281        if !changed {
2282            return;
2283        }
2284        let edits = Self::sync_(
2285            &mut self.snapshot.borrow_mut(),
2286            &self.buffers,
2287            &self.diffs,
2288            cx,
2289        );
2290        if !edits.is_empty() {
2291            self.subscriptions.publish(edits);
2292        }
2293    }
2294
2295    fn sync_mut(&mut self, cx: &App) {
2296        let changed = self.buffer_changed_since_sync.replace(false);
2297        if !changed {
2298            return;
2299        }
2300        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2301
2302        if !edits.is_empty() {
2303            self.subscriptions.publish(edits);
2304        }
2305    }
2306
2307    fn sync_(
2308        snapshot: &mut MultiBufferSnapshot,
2309        buffers: &HashMap<BufferId, BufferState>,
2310        diffs: &HashMap<BufferId, DiffState>,
2311        cx: &App,
2312    ) -> Vec<Edit<usize>> {
2313        let MultiBufferSnapshot {
2314            excerpts,
2315            diffs: buffer_diff,
2316            diff_transforms: _,
2317            non_text_state_update_count,
2318            edit_count,
2319            is_dirty,
2320            has_deleted_file,
2321            has_conflict,
2322            singleton: _,
2323            excerpt_ids: _,
2324            replaced_excerpts: _,
2325            trailing_excerpt_update_count: _,
2326            all_diff_hunks_expanded: _,
2327            show_headers: _,
2328        } = snapshot;
2329        *is_dirty = false;
2330        *has_deleted_file = false;
2331        *has_conflict = false;
2332
2333        let mut excerpts_to_edit = Vec::new();
2334        let mut non_text_state_updated = false;
2335        let mut edited = false;
2336        for buffer_state in buffers.values() {
2337            let buffer = buffer_state.buffer.read(cx);
2338            let version = buffer.version();
2339            let non_text_state_update_count = buffer.non_text_state_update_count();
2340
2341            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2342            let buffer_non_text_state_updated =
2343                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2344            if buffer_edited || buffer_non_text_state_updated {
2345                *buffer_state.last_version.borrow_mut() = version;
2346                buffer_state
2347                    .last_non_text_state_update_count
2348                    .set(non_text_state_update_count);
2349                excerpts_to_edit.extend(
2350                    buffer_state
2351                        .excerpts
2352                        .iter()
2353                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2354                );
2355            }
2356
2357            edited |= buffer_edited;
2358            non_text_state_updated |= buffer_non_text_state_updated;
2359            *is_dirty |= buffer.is_dirty();
2360            *has_deleted_file |= buffer
2361                .file()
2362                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
2363            *has_conflict |= buffer.has_conflict();
2364        }
2365        if edited {
2366            *edit_count += 1;
2367        }
2368        if non_text_state_updated {
2369            *non_text_state_update_count += 1;
2370        }
2371
2372        for (id, diff) in diffs.iter() {
2373            if buffer_diff.get(id).is_none() {
2374                buffer_diff.insert(*id, diff.diff.read(cx).snapshot(cx));
2375            }
2376        }
2377
2378        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2379
2380        let mut edits = Vec::new();
2381        let mut new_excerpts = SumTree::default();
2382        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2383
2384        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2385            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2386            let old_excerpt = cursor.item().unwrap();
2387            let buffer = buffer.read(cx);
2388            let buffer_id = buffer.remote_id();
2389
2390            let mut new_excerpt;
2391            if buffer_edited {
2392                edits.extend(
2393                    buffer
2394                        .edits_since_in_range::<usize>(
2395                            old_excerpt.buffer.version(),
2396                            old_excerpt.range.context.clone(),
2397                        )
2398                        .map(|edit| {
2399                            let excerpt_old_start = cursor.start().1;
2400                            let excerpt_new_start =
2401                                ExcerptOffset::new(new_excerpts.summary().text.len);
2402                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2403                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2404                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2405                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2406                            Edit {
2407                                old: old_start..old_end,
2408                                new: new_start..new_end,
2409                            }
2410                        }),
2411                );
2412
2413                new_excerpt = Excerpt::new(
2414                    old_excerpt.id,
2415                    locator.clone(),
2416                    buffer_id,
2417                    buffer.snapshot(),
2418                    old_excerpt.range.clone(),
2419                    old_excerpt.has_trailing_newline,
2420                );
2421            } else {
2422                new_excerpt = old_excerpt.clone();
2423                new_excerpt.buffer = buffer.snapshot();
2424            }
2425
2426            new_excerpts.push(new_excerpt, ());
2427            cursor.next();
2428        }
2429        new_excerpts.append(cursor.suffix(), ());
2430
2431        drop(cursor);
2432        *excerpts = new_excerpts;
2433        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2434    }
2435
2436    fn sync_diff_transforms(
2437        snapshot: &mut MultiBufferSnapshot,
2438        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2439        change_kind: DiffChangeKind,
2440    ) -> Vec<Edit<usize>> {
2441        if excerpt_edits.is_empty() {
2442            return vec![];
2443        }
2444
2445        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2446        let mut old_diff_transforms = snapshot
2447            .diff_transforms
2448            .cursor::<Dimensions<ExcerptOffset, usize>>(());
2449        let mut new_diff_transforms = SumTree::default();
2450        let mut old_expanded_hunks = HashSet::default();
2451        let mut output_edits = Vec::new();
2452        let mut output_delta = 0_isize;
2453        let mut at_transform_boundary = true;
2454        let mut end_of_current_insert = None;
2455
2456        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2457        while let Some(edit) = excerpt_edits.next() {
2458            excerpts.seek_forward(&edit.new.start, Bias::Right);
2459            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2460                excerpts.prev();
2461            }
2462
2463            // Keep any transforms that are before the edit.
2464            if at_transform_boundary {
2465                at_transform_boundary = false;
2466                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2467                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2468                if let Some(transform) = old_diff_transforms.item()
2469                    && old_diff_transforms.end().0 == edit.old.start
2470                    && old_diff_transforms.start().0 < edit.old.start
2471                {
2472                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2473                    old_diff_transforms.next();
2474                }
2475            }
2476
2477            // Compute the start of the edit in output coordinates.
2478            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2479            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2480            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2481
2482            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2483                &edit,
2484                &mut excerpts,
2485                &mut old_diff_transforms,
2486                &mut new_diff_transforms,
2487                &mut end_of_current_insert,
2488                &mut old_expanded_hunks,
2489                snapshot,
2490                change_kind,
2491            );
2492
2493            // Compute the end of the edit in output coordinates.
2494            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2495            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2496            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2497            let edit_new_end =
2498                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2499            let output_edit = Edit {
2500                old: edit_old_start..edit_old_end,
2501                new: edit_new_start..edit_new_end,
2502            };
2503
2504            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2505            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2506            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2507                output_edits.push(output_edit);
2508            }
2509
2510            // If this is the last edit that intersects the current diff transform,
2511            // then recreate the content up to the end of this transform, to prepare
2512            // for reusing additional slices of the old transforms.
2513            if excerpt_edits
2514                .peek()
2515                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2516            {
2517                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2518                    && match old_diff_transforms.item() {
2519                        Some(DiffTransform::BufferContent {
2520                            inserted_hunk_info: Some(hunk),
2521                            ..
2522                        }) => excerpts.item().is_some_and(|excerpt| {
2523                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2524                        }),
2525                        _ => true,
2526                    };
2527
2528                let mut excerpt_offset = edit.new.end;
2529                if !keep_next_old_transform {
2530                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2531                    old_diff_transforms.next();
2532                }
2533
2534                old_expanded_hunks.clear();
2535                Self::push_buffer_content_transform(
2536                    snapshot,
2537                    &mut new_diff_transforms,
2538                    excerpt_offset,
2539                    end_of_current_insert,
2540                );
2541                at_transform_boundary = true;
2542            }
2543        }
2544
2545        // Keep any transforms that are after the last edit.
2546        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2547
2548        // Ensure there's always at least one buffer content transform.
2549        if new_diff_transforms.is_empty() {
2550            new_diff_transforms.push(
2551                DiffTransform::BufferContent {
2552                    summary: Default::default(),
2553                    inserted_hunk_info: None,
2554                },
2555                (),
2556            );
2557        }
2558
2559        drop(old_diff_transforms);
2560        drop(excerpts);
2561        snapshot.diff_transforms = new_diff_transforms;
2562        snapshot.edit_count += 1;
2563
2564        #[cfg(any(test, feature = "test-support"))]
2565        snapshot.check_invariants();
2566        output_edits
2567    }
2568
2569    fn recompute_diff_transforms_for_edit(
2570        edit: &Edit<TypedOffset<Excerpt>>,
2571        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2572        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
2573        new_diff_transforms: &mut SumTree<DiffTransform>,
2574        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2575        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2576        snapshot: &MultiBufferSnapshot,
2577        change_kind: DiffChangeKind,
2578    ) -> bool {
2579        log::trace!(
2580            "recomputing diff transform for edit {:?} => {:?}",
2581            edit.old.start.value..edit.old.end.value,
2582            edit.new.start.value..edit.new.end.value
2583        );
2584
2585        // Record which hunks were previously expanded.
2586        while let Some(item) = old_diff_transforms.item() {
2587            if let Some(hunk_info) = item.hunk_info() {
2588                log::trace!(
2589                    "previously expanded hunk at {}",
2590                    old_diff_transforms.start().0
2591                );
2592                old_expanded_hunks.insert(hunk_info);
2593            }
2594            if old_diff_transforms.end().0 > edit.old.end {
2595                break;
2596            }
2597            old_diff_transforms.next();
2598        }
2599
2600        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2601        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2602        if old_expanded_hunks.is_empty()
2603            && change_kind == DiffChangeKind::BufferEdited
2604            && !all_diff_hunks_expanded
2605        {
2606            return false;
2607        }
2608
2609        // Visit each excerpt that intersects the edit.
2610        let mut did_expand_hunks = false;
2611        while let Some(excerpt) = excerpts.item() {
2612            // Recompute the expanded hunks in the portion of the excerpt that
2613            // intersects the edit.
2614            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2615                let buffer = &excerpt.buffer;
2616                let excerpt_start = *excerpts.start();
2617                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2618                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2619                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2620                let edit_buffer_start =
2621                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2622                let edit_buffer_end =
2623                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2624                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2625                let edit_anchor_range =
2626                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2627
2628                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2629                    if hunk.is_created_file() && !all_diff_hunks_expanded {
2630                        continue;
2631                    }
2632
2633                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2634                    if hunk_buffer_range.start < excerpt_buffer_start {
2635                        log::trace!("skipping hunk that starts before excerpt");
2636                        continue;
2637                    }
2638
2639                    let hunk_info = DiffTransformHunkInfo {
2640                        excerpt_id: excerpt.id,
2641                        hunk_start_anchor: hunk.buffer_range.start,
2642                        hunk_secondary_status: hunk.secondary_status,
2643                    };
2644
2645                    let hunk_excerpt_start = excerpt_start
2646                        + ExcerptOffset::new(
2647                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2648                        );
2649                    let hunk_excerpt_end = excerpt_end.min(
2650                        excerpt_start
2651                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2652                    );
2653
2654                    Self::push_buffer_content_transform(
2655                        snapshot,
2656                        new_diff_transforms,
2657                        hunk_excerpt_start,
2658                        *end_of_current_insert,
2659                    );
2660
2661                    // For every existing hunk, determine if it was previously expanded
2662                    // and if it should currently be expanded.
2663                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2664                    let should_expand_hunk = match &change_kind {
2665                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2666                            was_previously_expanded || all_diff_hunks_expanded
2667                        }
2668                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2669                            let intersects = hunk_buffer_range.is_empty()
2670                                || hunk_buffer_range.end > edit_buffer_start;
2671                            if *expand {
2672                                intersects || was_previously_expanded || all_diff_hunks_expanded
2673                            } else {
2674                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
2675                            }
2676                        }
2677                        _ => was_previously_expanded || all_diff_hunks_expanded,
2678                    };
2679
2680                    if should_expand_hunk {
2681                        did_expand_hunks = true;
2682                        log::trace!(
2683                            "expanding hunk {:?}, excerpt:{:?}",
2684                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2685                            excerpt.id
2686                        );
2687
2688                        if !hunk.diff_base_byte_range.is_empty()
2689                            && hunk_buffer_range.start >= edit_buffer_start
2690                            && hunk_buffer_range.start <= excerpt_buffer_end
2691                        {
2692                            let base_text = diff.base_text();
2693                            let mut text_cursor =
2694                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2695                            let mut base_text_summary =
2696                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2697
2698                            let mut has_trailing_newline = false;
2699                            if base_text_summary.last_line_chars > 0 {
2700                                base_text_summary += TextSummary::newline();
2701                                has_trailing_newline = true;
2702                            }
2703
2704                            new_diff_transforms.push(
2705                                DiffTransform::DeletedHunk {
2706                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2707                                    summary: base_text_summary,
2708                                    buffer_id: excerpt.buffer_id,
2709                                    hunk_info,
2710                                    has_trailing_newline,
2711                                },
2712                                (),
2713                            );
2714                        }
2715
2716                        if !hunk_buffer_range.is_empty() {
2717                            *end_of_current_insert =
2718                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2719                        }
2720                    }
2721                }
2722            }
2723
2724            if excerpts.end() <= edit.new.end {
2725                excerpts.next();
2726            } else {
2727                break;
2728            }
2729        }
2730
2731        did_expand_hunks || !old_expanded_hunks.is_empty()
2732    }
2733
2734    fn append_diff_transforms(
2735        new_transforms: &mut SumTree<DiffTransform>,
2736        subtree: SumTree<DiffTransform>,
2737    ) {
2738        if let Some(DiffTransform::BufferContent {
2739            inserted_hunk_info,
2740            summary,
2741        }) = subtree.first()
2742            && Self::extend_last_buffer_content_transform(
2743                new_transforms,
2744                *inserted_hunk_info,
2745                *summary,
2746            )
2747        {
2748            let mut cursor = subtree.cursor::<()>(());
2749            cursor.next();
2750            cursor.next();
2751            new_transforms.append(cursor.suffix(), ());
2752            return;
2753        }
2754        new_transforms.append(subtree, ());
2755    }
2756
2757    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
2758        if let DiffTransform::BufferContent {
2759            inserted_hunk_info: inserted_hunk_anchor,
2760            summary,
2761        } = transform
2762            && Self::extend_last_buffer_content_transform(
2763                new_transforms,
2764                inserted_hunk_anchor,
2765                summary,
2766            )
2767        {
2768            return;
2769        }
2770        new_transforms.push(transform, ());
2771    }
2772
2773    fn push_buffer_content_transform(
2774        old_snapshot: &MultiBufferSnapshot,
2775        new_transforms: &mut SumTree<DiffTransform>,
2776        end_offset: ExcerptOffset,
2777        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2778    ) {
2779        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
2780            (end_offset.min(insertion_end_offset), Some(hunk_info))
2781        });
2782        let unchanged_region = [(end_offset, None)];
2783
2784        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
2785        {
2786            let start_offset = new_transforms.summary().excerpt_len();
2787            if end_offset <= start_offset {
2788                continue;
2789            }
2790            let summary_to_add = old_snapshot
2791                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
2792
2793            if !Self::extend_last_buffer_content_transform(
2794                new_transforms,
2795                inserted_hunk_info,
2796                summary_to_add,
2797            ) {
2798                new_transforms.push(
2799                    DiffTransform::BufferContent {
2800                        summary: summary_to_add,
2801                        inserted_hunk_info,
2802                    },
2803                    (),
2804                )
2805            }
2806        }
2807    }
2808
2809    fn extend_last_buffer_content_transform(
2810        new_transforms: &mut SumTree<DiffTransform>,
2811        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
2812        summary_to_add: TextSummary,
2813    ) -> bool {
2814        let mut did_extend = false;
2815        new_transforms.update_last(
2816            |last_transform| {
2817                if let DiffTransform::BufferContent {
2818                    summary,
2819                    inserted_hunk_info: inserted_hunk_anchor,
2820                } = last_transform
2821                    && *inserted_hunk_anchor == new_inserted_hunk_info
2822                {
2823                    *summary += summary_to_add;
2824                    did_extend = true;
2825                }
2826            },
2827            (),
2828        );
2829        did_extend
2830    }
2831}
2832
2833fn build_excerpt_ranges(
2834    ranges: impl IntoIterator<Item = Range<Point>>,
2835    context_line_count: u32,
2836    buffer_snapshot: &BufferSnapshot,
2837) -> Vec<ExcerptRange<Point>> {
2838    ranges
2839        .into_iter()
2840        .map(|range| {
2841            let start_row = range.start.row.saturating_sub(context_line_count);
2842            let start = Point::new(start_row, 0);
2843            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
2844            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
2845            ExcerptRange {
2846                context: start..end,
2847                primary: range,
2848            }
2849        })
2850        .collect()
2851}
2852
2853#[cfg(any(test, feature = "test-support"))]
2854impl MultiBuffer {
2855    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
2856        let buffer = cx.new(|cx| Buffer::local(text, cx));
2857        cx.new(|cx| Self::singleton(buffer, cx))
2858    }
2859
2860    pub fn build_multi<const COUNT: usize>(
2861        excerpts: [(&str, Vec<Range<Point>>); COUNT],
2862        cx: &mut gpui::App,
2863    ) -> Entity<Self> {
2864        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
2865        for (text, ranges) in excerpts {
2866            let buffer = cx.new(|cx| Buffer::local(text, cx));
2867            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
2868            multi.update(cx, |multi, cx| {
2869                multi.push_excerpts(buffer, excerpt_ranges, cx)
2870            });
2871        }
2872
2873        multi
2874    }
2875
2876    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
2877        cx.new(|cx| Self::singleton(buffer, cx))
2878    }
2879
2880    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
2881        cx.new(|cx| {
2882            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
2883            let mutation_count = rng.random_range(1..=5);
2884            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
2885            multibuffer
2886        })
2887    }
2888
2889    pub fn randomly_edit(
2890        &mut self,
2891        rng: &mut impl rand::Rng,
2892        edit_count: usize,
2893        cx: &mut Context<Self>,
2894    ) {
2895        use util::RandomCharIter;
2896
2897        let snapshot = self.read(cx);
2898        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
2899        let mut last_end = None;
2900        for _ in 0..edit_count {
2901            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
2902                break;
2903            }
2904
2905            let new_start = last_end.map_or(0, |last_end| last_end + 1);
2906            let end =
2907                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
2908            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
2909            last_end = Some(end);
2910
2911            let mut range = start..end;
2912            if rng.random_bool(0.2) {
2913                mem::swap(&mut range.start, &mut range.end);
2914            }
2915
2916            let new_text_len = rng.random_range(0..10);
2917            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
2918
2919            edits.push((range, new_text.into()));
2920        }
2921        log::info!("mutating multi-buffer with {:?}", edits);
2922        drop(snapshot);
2923
2924        self.edit(edits, None, cx);
2925    }
2926
2927    pub fn randomly_edit_excerpts(
2928        &mut self,
2929        rng: &mut impl rand::Rng,
2930        mutation_count: usize,
2931        cx: &mut Context<Self>,
2932    ) {
2933        use rand::prelude::*;
2934        use std::env;
2935        use util::RandomCharIter;
2936
2937        let max_excerpts = env::var("MAX_EXCERPTS")
2938            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
2939            .unwrap_or(5);
2940
2941        let mut buffers = Vec::new();
2942        for _ in 0..mutation_count {
2943            if rng.random_bool(0.05) {
2944                log::info!("Clearing multi-buffer");
2945                self.clear(cx);
2946                continue;
2947            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
2948                let ids = self.excerpt_ids();
2949                let mut excerpts = HashSet::default();
2950                for _ in 0..rng.random_range(0..ids.len()) {
2951                    excerpts.extend(ids.choose(rng).copied());
2952                }
2953
2954                let line_count = rng.random_range(0..5);
2955
2956                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
2957
2958                self.expand_excerpts(
2959                    excerpts.iter().cloned(),
2960                    line_count,
2961                    ExpandExcerptDirection::UpAndDown,
2962                    cx,
2963                );
2964                continue;
2965            }
2966
2967            let excerpt_ids = self.excerpt_ids();
2968            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
2969                let buffer_handle = if rng.random() || self.buffers.is_empty() {
2970                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
2971                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
2972                    let buffer = buffers.last().unwrap().read(cx);
2973                    log::info!(
2974                        "Creating new buffer {} with text: {:?}",
2975                        buffer.remote_id(),
2976                        buffer.text()
2977                    );
2978                    buffers.last().unwrap().clone()
2979                } else {
2980                    self.buffers.values().choose(rng).unwrap().buffer.clone()
2981                };
2982
2983                let buffer = buffer_handle.read(cx);
2984                let buffer_text = buffer.text();
2985                let ranges = (0..rng.random_range(0..5))
2986                    .map(|_| {
2987                        let end_ix =
2988                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
2989                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
2990                        ExcerptRange::new(start_ix..end_ix)
2991                    })
2992                    .collect::<Vec<_>>();
2993                log::info!(
2994                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
2995                    buffer_handle.read(cx).remote_id(),
2996                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
2997                    ranges
2998                        .iter()
2999                        .map(|r| &buffer_text[r.context.clone()])
3000                        .collect::<Vec<_>>()
3001                );
3002
3003                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3004                log::info!("Inserted with ids: {:?}", excerpt_id);
3005            } else {
3006                let remove_count = rng.random_range(1..=excerpt_ids.len());
3007                let mut excerpts_to_remove = excerpt_ids
3008                    .choose_multiple(rng, remove_count)
3009                    .cloned()
3010                    .collect::<Vec<_>>();
3011                let snapshot = self.snapshot.borrow();
3012                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3013                drop(snapshot);
3014                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3015                self.remove_excerpts(excerpts_to_remove, cx);
3016            }
3017        }
3018    }
3019
3020    pub fn randomly_mutate(
3021        &mut self,
3022        rng: &mut impl rand::Rng,
3023        mutation_count: usize,
3024        cx: &mut Context<Self>,
3025    ) {
3026        use rand::prelude::*;
3027
3028        if rng.random_bool(0.7) || self.singleton {
3029            let buffer = self
3030                .buffers
3031                .values()
3032                .choose(rng)
3033                .map(|state| state.buffer.clone());
3034
3035            if let Some(buffer) = buffer {
3036                buffer.update(cx, |buffer, cx| {
3037                    if rng.random() {
3038                        buffer.randomly_edit(rng, mutation_count, cx);
3039                    } else {
3040                        buffer.randomly_undo_redo(rng, cx);
3041                    }
3042                });
3043            } else {
3044                self.randomly_edit(rng, mutation_count, cx);
3045            }
3046        } else {
3047            self.randomly_edit_excerpts(rng, mutation_count, cx);
3048        }
3049
3050        self.check_invariants(cx);
3051    }
3052
3053    fn check_invariants(&self, cx: &App) {
3054        self.read(cx).check_invariants();
3055    }
3056}
3057
3058impl EventEmitter<Event> for MultiBuffer {}
3059
3060impl MultiBufferSnapshot {
3061    pub fn text(&self) -> String {
3062        self.chunks(0..self.len(), false)
3063            .map(|chunk| chunk.text)
3064            .collect()
3065    }
3066
3067    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3068        self.reversed_chunks_in_range(0..position.to_offset(self))
3069            .flat_map(|c| c.chars().rev())
3070    }
3071
3072    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3073        let mut cursor = self.cursor::<usize>();
3074        cursor.seek(&range.end);
3075        let current_chunks = cursor.region().as_ref().map(|region| {
3076            let start_overshoot = range.start.saturating_sub(region.range.start);
3077            let end_overshoot = range.end - region.range.start;
3078            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3079            let start = region.buffer_range.start + start_overshoot;
3080            region.buffer.reversed_chunks_in_range(start..end)
3081        });
3082        ReversedMultiBufferChunks {
3083            cursor,
3084            current_chunks,
3085            start: range.start,
3086            offset: range.end,
3087        }
3088    }
3089
3090    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3091        let offset = position.to_offset(self);
3092        self.text_for_range(offset..self.len())
3093            .flat_map(|chunk| chunk.chars())
3094    }
3095
3096    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3097        self.chunks(range, false).map(|chunk| chunk.text)
3098    }
3099
3100    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3101        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3102            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3103    }
3104
3105    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3106    where
3107        T: ToOffset,
3108    {
3109        let position = position.to_offset(self);
3110        position == self.clip_offset(position, Bias::Left)
3111            && self
3112                .bytes_in_range(position..self.len())
3113                .flatten()
3114                .copied()
3115                .take(needle.len())
3116                .eq(needle.bytes())
3117    }
3118
3119    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3120        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3121    }
3122
3123    pub fn diff_hunks_in_range<T: ToPoint>(
3124        &self,
3125        range: Range<T>,
3126    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3127        let query_range = range.start.to_point(self)..range.end.to_point(self);
3128        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3129            let diff = self.diffs.get(&buffer.remote_id())?;
3130            let buffer_start = buffer.anchor_before(buffer_range.start);
3131            let buffer_end = buffer.anchor_after(buffer_range.end);
3132            Some(
3133                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3134                    .filter_map(|hunk| {
3135                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3136                            return None;
3137                        }
3138                        Some((hunk.range.clone(), hunk))
3139                    }),
3140            )
3141        })
3142        .filter_map(move |(range, hunk, excerpt)| {
3143            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3144            {
3145                return None;
3146            }
3147            let end_row = if range.end.column == 0 {
3148                range.end.row
3149            } else {
3150                range.end.row + 1
3151            };
3152            Some(MultiBufferDiffHunk {
3153                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3154                buffer_id: excerpt.buffer_id,
3155                excerpt_id: excerpt.id,
3156                buffer_range: hunk.buffer_range.clone(),
3157                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3158                secondary_status: hunk.secondary_status,
3159            })
3160        })
3161    }
3162
3163    pub fn excerpt_ids_for_range<T: ToOffset>(
3164        &self,
3165        range: Range<T>,
3166    ) -> impl Iterator<Item = ExcerptId> + '_ {
3167        let range = range.start.to_offset(self)..range.end.to_offset(self);
3168        let mut cursor = self.cursor::<usize>();
3169        cursor.seek(&range.start);
3170        std::iter::from_fn(move || {
3171            let region = cursor.region()?;
3172            if region.range.start >= range.end {
3173                return None;
3174            }
3175            cursor.next_excerpt();
3176            Some(region.excerpt.id)
3177        })
3178    }
3179
3180    pub fn buffer_ids_for_range<T: ToOffset>(
3181        &self,
3182        range: Range<T>,
3183    ) -> impl Iterator<Item = BufferId> + '_ {
3184        let range = range.start.to_offset(self)..range.end.to_offset(self);
3185        let mut cursor = self.cursor::<usize>();
3186        cursor.seek(&range.start);
3187        std::iter::from_fn(move || {
3188            let region = cursor.region()?;
3189            if region.range.start > range.end
3190                || region.range.start == range.end && region.range.start > range.start
3191            {
3192                return None;
3193            }
3194            cursor.next_excerpt();
3195            Some(region.excerpt.buffer_id)
3196        })
3197    }
3198
3199    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3200        &self,
3201        ranges: impl Iterator<Item = Range<T>>,
3202    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3203        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3204    }
3205
3206    pub fn range_to_buffer_ranges<T: ToOffset>(
3207        &self,
3208        range: Range<T>,
3209    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3210        let start = range.start.to_offset(self);
3211        let end = range.end.to_offset(self);
3212
3213        let mut cursor = self.cursor::<usize>();
3214        cursor.seek(&start);
3215
3216        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3217        while let Some(region) = cursor.region() {
3218            if region.range.start > end {
3219                break;
3220            }
3221            if region.is_main_buffer {
3222                let start_overshoot = start.saturating_sub(region.range.start);
3223                let end_overshoot = end.saturating_sub(region.range.start);
3224                let start = region
3225                    .buffer_range
3226                    .end
3227                    .min(region.buffer_range.start + start_overshoot);
3228                let end = region
3229                    .buffer_range
3230                    .end
3231                    .min(region.buffer_range.start + end_overshoot);
3232                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3233                    *excerpt_id == region.excerpt.id && prev_range.end == start
3234                }) {
3235                    prev.1.end = end;
3236                } else {
3237                    result.push((region.buffer, start..end, region.excerpt.id));
3238                }
3239            }
3240            cursor.next();
3241        }
3242        result
3243    }
3244
3245    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3246        &self,
3247        range: Range<T>,
3248    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3249        let start = range.start.to_offset(self);
3250        let end = range.end.to_offset(self);
3251
3252        let mut cursor = self.cursor::<usize>();
3253        cursor.seek(&start);
3254
3255        std::iter::from_fn(move || {
3256            let region = cursor.region()?;
3257            if region.range.start > end {
3258                return None;
3259            }
3260            let start_overshoot = start.saturating_sub(region.range.start);
3261            let end_overshoot = end.saturating_sub(region.range.start);
3262            let start = region
3263                .buffer_range
3264                .end
3265                .min(region.buffer_range.start + start_overshoot);
3266            let end = region
3267                .buffer_range
3268                .end
3269                .min(region.buffer_range.start + end_overshoot);
3270
3271            let region_excerpt_id = region.excerpt.id;
3272            let deleted_hunk_anchor = if region.is_main_buffer {
3273                None
3274            } else {
3275                Some(self.anchor_before(region.range.start))
3276            };
3277            let result = (
3278                region.buffer,
3279                start..end,
3280                region_excerpt_id,
3281                deleted_hunk_anchor,
3282            );
3283            cursor.next();
3284            Some(result)
3285        })
3286    }
3287
3288    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3289    /// coordinates.
3290    ///
3291    /// The given callback will be called for every excerpt intersecting the given range. It will
3292    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3293    /// The callback should return an iterator of metadata items from that buffer, each paired
3294    /// with a buffer range.
3295    ///
3296    /// The returned iterator yields each of these metadata items, paired with its range in
3297    /// multi-buffer coordinates.
3298    fn lift_buffer_metadata<'a, D, M, I>(
3299        &'a self,
3300        query_range: Range<D>,
3301        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3302    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3303    where
3304        I: Iterator<Item = (Range<D>, M)> + 'a,
3305        D: TextDimension + Ord + Sub<D, Output = D>,
3306    {
3307        let max_position = D::from_text_summary(&self.text_summary());
3308        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3309        let mut cursor = self.cursor::<D>();
3310
3311        // Find the excerpt and buffer offset where the given range ends.
3312        cursor.seek(&query_range.end);
3313        let mut range_end = None;
3314        while let Some(region) = cursor.region() {
3315            if region.is_main_buffer {
3316                let mut buffer_end = region.buffer_range.start;
3317                let overshoot = if query_range.end > region.range.start {
3318                    query_range.end - region.range.start
3319                } else {
3320                    D::default()
3321                };
3322                buffer_end.add_assign(&overshoot);
3323                range_end = Some((region.excerpt.id, buffer_end));
3324                break;
3325            }
3326            cursor.next();
3327        }
3328
3329        cursor.seek(&query_range.start);
3330
3331        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3332            && region.range.start > D::zero(())
3333        {
3334            cursor.prev()
3335        }
3336
3337        iter::from_fn(move || {
3338            loop {
3339                let excerpt = cursor.excerpt()?;
3340
3341                // If we have already retrieved metadata for this excerpt, continue to use it.
3342                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3343                    .as_mut()
3344                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3345                {
3346                    Some(metadata)
3347                }
3348                // Otherwise, compute the intersection of the input range with the excerpt's range,
3349                // and retrieve the metadata for the resulting range.
3350                else {
3351                    let region = cursor.region()?;
3352                    let mut buffer_start;
3353                    if region.is_main_buffer {
3354                        buffer_start = region.buffer_range.start;
3355                        if query_range.start > region.range.start {
3356                            let overshoot = query_range.start - region.range.start;
3357                            buffer_start.add_assign(&overshoot);
3358                        }
3359                        buffer_start = buffer_start.min(region.buffer_range.end);
3360                    } else {
3361                        buffer_start = cursor.main_buffer_position()?;
3362                    };
3363                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3364                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
3365                        && excerpt.id == end_excerpt_id
3366                    {
3367                        buffer_end = buffer_end.min(end_buffer_offset);
3368                    }
3369
3370                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
3371                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
3372                    })
3373                };
3374
3375                // Visit each metadata item.
3376                if let Some((metadata_buffer_range, metadata)) =
3377                    metadata_iter.and_then(Iterator::next)
3378                {
3379                    // Find the multibuffer regions that contain the start and end of
3380                    // the metadata item's range.
3381                    if metadata_buffer_range.start > D::default() {
3382                        while let Some(region) = cursor.region() {
3383                            if region.is_main_buffer
3384                                && (region.buffer_range.end >= metadata_buffer_range.start
3385                                    || cursor.is_at_end_of_excerpt())
3386                            {
3387                                break;
3388                            }
3389                            cursor.next();
3390                        }
3391                    }
3392                    let start_region = cursor.region()?;
3393                    while let Some(region) = cursor.region() {
3394                        if region.is_main_buffer
3395                            && (region.buffer_range.end > metadata_buffer_range.end
3396                                || cursor.is_at_end_of_excerpt())
3397                        {
3398                            break;
3399                        }
3400                        cursor.next();
3401                    }
3402                    let end_region = cursor.region();
3403
3404                    // Convert the metadata item's range into multibuffer coordinates.
3405                    let mut start_position = start_region.range.start;
3406                    let region_buffer_start = start_region.buffer_range.start;
3407                    if start_region.is_main_buffer
3408                        && metadata_buffer_range.start > region_buffer_start
3409                    {
3410                        start_position
3411                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
3412                        start_position = start_position.min(start_region.range.end);
3413                    }
3414
3415                    let mut end_position = max_position;
3416                    if let Some(end_region) = &end_region {
3417                        end_position = end_region.range.start;
3418                        debug_assert!(end_region.is_main_buffer);
3419                        let region_buffer_start = end_region.buffer_range.start;
3420                        if metadata_buffer_range.end > region_buffer_start {
3421                            end_position
3422                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
3423                        }
3424                        end_position = end_position.min(end_region.range.end);
3425                    }
3426
3427                    if start_position <= query_range.end && end_position >= query_range.start {
3428                        return Some((start_position..end_position, metadata, excerpt));
3429                    }
3430                }
3431                // When there are no more metadata items for this excerpt, move to the next excerpt.
3432                else {
3433                    current_excerpt_metadata.take();
3434                    if let Some((end_excerpt_id, _)) = range_end
3435                        && excerpt.id == end_excerpt_id
3436                    {
3437                        return None;
3438                    }
3439                    cursor.next_excerpt();
3440                }
3441            }
3442        })
3443    }
3444
3445    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3446        let offset = position.to_offset(self);
3447
3448        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
3449        cursor.seek(&DimensionPair {
3450            key: offset,
3451            value: None,
3452        });
3453        cursor.seek_to_start_of_current_excerpt();
3454        let excerpt = cursor.excerpt()?;
3455
3456        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3457        let current_position = self
3458            .anchor_before(offset)
3459            .text_anchor
3460            .to_offset(&excerpt.buffer);
3461        let excerpt_end = excerpt
3462            .buffer
3463            .anchor_before(excerpt_end.min(current_position));
3464
3465        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3466            for hunk in diff.hunks_intersecting_range_rev(
3467                excerpt.range.context.start..excerpt_end,
3468                &excerpt.buffer,
3469            ) {
3470                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3471                if hunk_end >= current_position {
3472                    continue;
3473                }
3474                let start =
3475                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3476                        .to_point(self);
3477                return Some(MultiBufferRow(start.row));
3478            }
3479        }
3480
3481        loop {
3482            cursor.prev_excerpt();
3483            let excerpt = cursor.excerpt()?;
3484
3485            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3486                continue;
3487            };
3488            let mut hunks =
3489                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3490            let Some(hunk) = hunks.next() else {
3491                continue;
3492            };
3493            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3494                .to_point(self);
3495            return Some(MultiBufferRow(start.row));
3496        }
3497    }
3498
3499    pub fn has_diff_hunks(&self) -> bool {
3500        self.diffs.values().any(|diff| !diff.is_empty())
3501    }
3502
3503    pub fn is_inside_word<T: ToOffset>(
3504        &self,
3505        position: T,
3506        scope_context: Option<CharScopeContext>,
3507    ) -> bool {
3508        let position = position.to_offset(self);
3509        let classifier = self
3510            .char_classifier_at(position)
3511            .scope_context(scope_context);
3512        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
3513        let prev_char_kind = self
3514            .reversed_chars_at(position)
3515            .next()
3516            .map(|c| classifier.kind(c));
3517        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
3518    }
3519
3520    pub fn surrounding_word<T: ToOffset>(
3521        &self,
3522        start: T,
3523        scope_context: Option<CharScopeContext>,
3524    ) -> (Range<usize>, Option<CharKind>) {
3525        let mut start = start.to_offset(self);
3526        let mut end = start;
3527        let mut next_chars = self.chars_at(start).peekable();
3528        let mut prev_chars = self.reversed_chars_at(start).peekable();
3529
3530        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3531
3532        let word_kind = cmp::max(
3533            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3534            next_chars.peek().copied().map(|c| classifier.kind(c)),
3535        );
3536
3537        for ch in prev_chars {
3538            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3539                start -= ch.len_utf8();
3540            } else {
3541                break;
3542            }
3543        }
3544
3545        for ch in next_chars {
3546            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3547                end += ch.len_utf8();
3548            } else {
3549                break;
3550            }
3551        }
3552
3553        (start..end, word_kind)
3554    }
3555
3556    pub fn char_kind_before<T: ToOffset>(
3557        &self,
3558        start: T,
3559        scope_context: Option<CharScopeContext>,
3560    ) -> Option<CharKind> {
3561        let start = start.to_offset(self);
3562        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3563        self.reversed_chars_at(start)
3564            .next()
3565            .map(|ch| classifier.kind(ch))
3566    }
3567
3568    pub fn is_singleton(&self) -> bool {
3569        self.singleton
3570    }
3571
3572    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3573        if self.singleton {
3574            self.excerpts
3575                .iter()
3576                .next()
3577                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3578        } else {
3579            None
3580        }
3581    }
3582
3583    pub fn len(&self) -> usize {
3584        self.diff_transforms.summary().output.len
3585    }
3586
3587    pub fn is_empty(&self) -> bool {
3588        self.excerpts.summary().text.len == 0
3589    }
3590
3591    pub fn widest_line_number(&self) -> u32 {
3592        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
3593        self.excerpts.summary().widest_line_number + 1
3594    }
3595
3596    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
3597        let range = range.start.to_offset(self)..range.end.to_offset(self);
3598        let mut excerpts = self.cursor::<usize>();
3599        excerpts.seek(&range.start);
3600
3601        let mut chunk;
3602        let mut has_trailing_newline;
3603        let excerpt_bytes;
3604        if let Some(region) = excerpts.region() {
3605            let mut bytes = region.buffer.bytes_in_range(
3606                region.buffer_range.start + range.start - region.range.start
3607                    ..(region.buffer_range.start + range.end - region.range.start)
3608                        .min(region.buffer_range.end),
3609            );
3610            chunk = bytes.next().unwrap_or(&[][..]);
3611            excerpt_bytes = Some(bytes);
3612            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3613            if chunk.is_empty() && has_trailing_newline {
3614                chunk = b"\n";
3615                has_trailing_newline = false;
3616            }
3617        } else {
3618            chunk = &[][..];
3619            excerpt_bytes = None;
3620            has_trailing_newline = false;
3621        };
3622
3623        MultiBufferBytes {
3624            range,
3625            cursor: excerpts,
3626            excerpt_bytes,
3627            has_trailing_newline,
3628            chunk,
3629        }
3630    }
3631
3632    pub fn reversed_bytes_in_range<T: ToOffset>(
3633        &self,
3634        range: Range<T>,
3635    ) -> ReversedMultiBufferBytes<'_> {
3636        let range = range.start.to_offset(self)..range.end.to_offset(self);
3637        let mut chunks = self.reversed_chunks_in_range(range.clone());
3638        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3639        ReversedMultiBufferBytes {
3640            range,
3641            chunks,
3642            chunk,
3643        }
3644    }
3645
3646    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
3647        let mut cursor = self.cursor::<Point>();
3648        cursor.seek(&Point::new(start_row.0, 0));
3649        let mut result = MultiBufferRows {
3650            point: Point::new(0, 0),
3651            is_empty: self.excerpts.is_empty(),
3652            is_singleton: self.is_singleton(),
3653            cursor,
3654        };
3655        result.seek(start_row);
3656        result
3657    }
3658
3659    pub fn chunks<T: ToOffset>(
3660        &self,
3661        range: Range<T>,
3662        language_aware: bool,
3663    ) -> MultiBufferChunks<'_> {
3664        let mut chunks = MultiBufferChunks {
3665            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3666            range: 0..0,
3667            excerpts: self.excerpts.cursor(()),
3668            diff_transforms: self.diff_transforms.cursor(()),
3669            diffs: &self.diffs,
3670            diff_base_chunks: None,
3671            excerpt_chunks: None,
3672            buffer_chunk: None,
3673            language_aware,
3674        };
3675        let range = range.start.to_offset(self)..range.end.to_offset(self);
3676        chunks.seek(range);
3677        chunks
3678    }
3679
3680    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3681        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3682    }
3683
3684    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
3685        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3686    }
3687
3688    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3689        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3690    }
3691
3692    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3693        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3694            buffer.clip_point_utf16(Unclipped(point), bias)
3695        })
3696    }
3697
3698    pub fn offset_to_point(&self, offset: usize) -> Point {
3699        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3700    }
3701
3702    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3703        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3704    }
3705
3706    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
3707        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3708    }
3709
3710    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
3711        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
3712    }
3713
3714    pub fn point_to_offset(&self, point: Point) -> usize {
3715        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3716    }
3717
3718    pub fn point_to_offset_utf16(&self, point: Point) -> OffsetUtf16 {
3719        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
3720    }
3721
3722    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3723        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3724    }
3725
3726    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3727        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3728    }
3729
3730    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3731        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3732    }
3733
3734    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> OffsetUtf16 {
3735        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
3736    }
3737
3738    fn clip_dimension<D>(
3739        &self,
3740        position: D,
3741        bias: Bias,
3742        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
3743    ) -> D
3744    where
3745        D: TextDimension + Ord + Sub<D, Output = D>,
3746    {
3747        let mut cursor = self.cursor();
3748        cursor.seek(&position);
3749        if let Some(region) = cursor.region() {
3750            if position >= region.range.end {
3751                return region.range.end;
3752            }
3753            let overshoot = position - region.range.start;
3754            let mut buffer_position = region.buffer_range.start;
3755            buffer_position.add_assign(&overshoot);
3756            let clipped_buffer_position =
3757                clip_buffer_position(region.buffer, buffer_position, bias);
3758            let mut position = region.range.start;
3759            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
3760            position
3761        } else {
3762            D::from_text_summary(&self.text_summary())
3763        }
3764    }
3765
3766    fn convert_dimension<D1, D2>(
3767        &self,
3768        key: D1,
3769        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
3770    ) -> D2
3771    where
3772        D1: TextDimension + Ord + Sub<D1, Output = D1>,
3773        D2: TextDimension + Ord + Sub<D2, Output = D2>,
3774    {
3775        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
3776        cursor.seek(&DimensionPair { key, value: None });
3777        if let Some(region) = cursor.region() {
3778            if key >= region.range.end.key {
3779                return region.range.end.value.unwrap();
3780            }
3781            let start_key = region.range.start.key;
3782            let start_value = region.range.start.value.unwrap();
3783            let buffer_start_key = region.buffer_range.start.key;
3784            let buffer_start_value = region.buffer_range.start.value.unwrap();
3785            let mut buffer_key = buffer_start_key;
3786            buffer_key.add_assign(&(key - start_key));
3787            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
3788            let mut result = start_value;
3789            result.add_assign(&(buffer_value - buffer_start_value));
3790            result
3791        } else {
3792            D2::from_text_summary(&self.text_summary())
3793        }
3794    }
3795
3796    pub fn point_to_buffer_offset<T: ToOffset>(
3797        &self,
3798        point: T,
3799    ) -> Option<(&BufferSnapshot, usize)> {
3800        let offset = point.to_offset(self);
3801        let mut cursor = self.cursor::<usize>();
3802        cursor.seek(&offset);
3803        let region = cursor.region()?;
3804        let overshoot = offset - region.range.start;
3805        let buffer_offset = region.buffer_range.start + overshoot;
3806        if buffer_offset == region.buffer.len() + 1
3807            && region.has_trailing_newline
3808            && !region.is_main_buffer
3809        {
3810            let main_buffer_position = cursor.main_buffer_position()?;
3811            let buffer_snapshot = &cursor.excerpt()?.buffer;
3812            // remove this assert once we figure out the cause of the panics for #40453
3813            buffer_snapshot
3814                .text
3815                .as_rope()
3816                .assert_char_boundary(main_buffer_position);
3817            return Some((buffer_snapshot, main_buffer_position));
3818        } else if buffer_offset > region.buffer.len() {
3819            return None;
3820        }
3821        // remove this assert once we figure out the cause of the panics for #40453
3822        region
3823            .buffer
3824            .text
3825            .as_rope()
3826            .assert_char_boundary(buffer_offset);
3827        Some((region.buffer, buffer_offset))
3828    }
3829
3830    pub fn point_to_buffer_point(
3831        &self,
3832        point: Point,
3833    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
3834        let mut cursor = self.cursor::<Point>();
3835        cursor.seek(&point);
3836        let region = cursor.region()?;
3837        let overshoot = point - region.range.start;
3838        let buffer_point = region.buffer_range.start + overshoot;
3839        let excerpt = cursor.excerpt()?;
3840        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
3841            && region.has_trailing_newline
3842            && !region.is_main_buffer
3843        {
3844            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
3845        } else if buffer_point > region.buffer.max_point() {
3846            return None;
3847        }
3848        Some((region.buffer, buffer_point, excerpt.id))
3849    }
3850
3851    pub fn suggested_indents(
3852        &self,
3853        rows: impl IntoIterator<Item = u32>,
3854        cx: &App,
3855    ) -> BTreeMap<MultiBufferRow, IndentSize> {
3856        let mut result = BTreeMap::new();
3857
3858        let mut rows_for_excerpt = Vec::new();
3859        let mut cursor = self.cursor::<Point>();
3860        let mut rows = rows.into_iter().peekable();
3861        let mut prev_row = u32::MAX;
3862        let mut prev_language_indent_size = IndentSize::default();
3863
3864        while let Some(row) = rows.next() {
3865            cursor.seek(&Point::new(row, 0));
3866            let Some(region) = cursor.region() else {
3867                continue;
3868            };
3869
3870            // Retrieve the language and indent size once for each disjoint region being indented.
3871            let single_indent_size = if row.saturating_sub(1) == prev_row {
3872                prev_language_indent_size
3873            } else {
3874                region
3875                    .buffer
3876                    .language_indent_size_at(Point::new(row, 0), cx)
3877            };
3878            prev_language_indent_size = single_indent_size;
3879            prev_row = row;
3880
3881            let start_buffer_row = region.buffer_range.start.row;
3882            let start_multibuffer_row = region.range.start.row;
3883            let end_multibuffer_row = region.range.end.row;
3884
3885            rows_for_excerpt.push(row);
3886            while let Some(next_row) = rows.peek().copied() {
3887                if end_multibuffer_row > next_row {
3888                    rows_for_excerpt.push(next_row);
3889                    rows.next();
3890                } else {
3891                    break;
3892                }
3893            }
3894
3895            let buffer_rows = rows_for_excerpt
3896                .drain(..)
3897                .map(|row| start_buffer_row + row - start_multibuffer_row);
3898            let buffer_indents = region
3899                .buffer
3900                .suggested_indents(buffer_rows, single_indent_size);
3901            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
3902                (
3903                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
3904                    indent,
3905                )
3906            });
3907            result.extend(multibuffer_indents);
3908        }
3909
3910        result
3911    }
3912
3913    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
3914        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3915            let mut size = buffer.indent_size_for_line(range.start.row);
3916            size.len = size
3917                .len
3918                .min(range.end.column)
3919                .saturating_sub(range.start.column);
3920            size
3921        } else {
3922            IndentSize::spaces(0)
3923        }
3924    }
3925
3926    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
3927        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
3928            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
3929        } else {
3930            LineIndent::spaces(0)
3931        }
3932    }
3933
3934    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
3935        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
3936
3937        if self.language_settings(cx).extend_comment_on_newline
3938            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
3939        {
3940            let delimiters = language_scope.line_comment_prefixes();
3941            for delimiter in delimiters {
3942                if *self
3943                    .chars_at(Point::new(row.0, indent.len() as u32))
3944                    .take(delimiter.chars().count())
3945                    .collect::<String>()
3946                    .as_str()
3947                    == **delimiter
3948                {
3949                    indent.push_str(delimiter);
3950                    break;
3951                }
3952            }
3953        }
3954
3955        indent
3956    }
3957
3958    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
3959    where
3960        T: ToOffset,
3961    {
3962        for char in self.reversed_chars_at(position) {
3963            if !char.is_whitespace() {
3964                return false;
3965            }
3966            if char == '\n' {
3967                return true;
3968            }
3969        }
3970        true
3971    }
3972
3973    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
3974        while row.0 > 0 {
3975            row.0 -= 1;
3976            if !self.is_line_blank(row) {
3977                return Some(row);
3978            }
3979        }
3980        None
3981    }
3982
3983    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
3984        if let Some((_, range)) = self.buffer_line_for_row(row) {
3985            range.end.column - range.start.column
3986        } else {
3987            0
3988        }
3989    }
3990
3991    pub fn buffer_line_for_row(
3992        &self,
3993        row: MultiBufferRow,
3994    ) -> Option<(&BufferSnapshot, Range<Point>)> {
3995        let mut cursor = self.cursor::<Point>();
3996        let point = Point::new(row.0, 0);
3997        cursor.seek(&point);
3998        let region = cursor.region()?;
3999        let overshoot = point.min(region.range.end) - region.range.start;
4000        let buffer_point = region.buffer_range.start + overshoot;
4001        if buffer_point.row > region.buffer_range.end.row {
4002            return None;
4003        }
4004        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4005        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4006            .min(region.buffer_range.end);
4007        Some((region.buffer, line_start..line_end))
4008    }
4009
4010    pub fn max_point(&self) -> Point {
4011        self.text_summary().lines
4012    }
4013
4014    pub fn max_row(&self) -> MultiBufferRow {
4015        MultiBufferRow(self.text_summary().lines.row)
4016    }
4017
4018    pub fn text_summary(&self) -> TextSummary {
4019        self.diff_transforms.summary().output
4020    }
4021
4022    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4023    where
4024        D: TextDimension,
4025        O: ToOffset,
4026    {
4027        let range = range.start.to_offset(self)..range.end.to_offset(self);
4028        let mut cursor = self
4029            .diff_transforms
4030            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4031        cursor.seek(&range.start, Bias::Right);
4032
4033        let Some(first_transform) = cursor.item() else {
4034            return D::from_text_summary(&TextSummary::default());
4035        };
4036
4037        let diff_transform_start = cursor.start().0;
4038        let diff_transform_end = cursor.end().0;
4039        let diff_start = range.start;
4040        let start_overshoot = diff_start - diff_transform_start;
4041        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4042
4043        let mut result = match first_transform {
4044            DiffTransform::BufferContent { .. } => {
4045                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4046                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4047                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4048            }
4049            DiffTransform::DeletedHunk {
4050                buffer_id,
4051                base_text_byte_range,
4052                has_trailing_newline,
4053                ..
4054            } => {
4055                let buffer_start = base_text_byte_range.start + start_overshoot;
4056                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4057                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4058                    panic!("{:?} is in non-existent deleted hunk", range.start)
4059                };
4060
4061                let include_trailing_newline =
4062                    *has_trailing_newline && range.end >= diff_transform_end;
4063                if include_trailing_newline {
4064                    buffer_end -= 1;
4065                }
4066
4067                let mut summary =
4068                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4069
4070                if include_trailing_newline {
4071                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4072                }
4073
4074                summary
4075            }
4076        };
4077        if range.end < diff_transform_end {
4078            return result;
4079        }
4080
4081        cursor.next();
4082        result.add_assign(&D::from_text_summary(
4083            &cursor.summary(&range.end, Bias::Right),
4084        ));
4085
4086        let Some(last_transform) = cursor.item() else {
4087            return result;
4088        };
4089
4090        let overshoot = range.end - cursor.start().0;
4091        let suffix = match last_transform {
4092            DiffTransform::BufferContent { .. } => {
4093                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4094                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4095            }
4096            DiffTransform::DeletedHunk {
4097                base_text_byte_range,
4098                buffer_id,
4099                has_trailing_newline,
4100                ..
4101            } => {
4102                let buffer_end = base_text_byte_range.start + overshoot;
4103                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4104                    panic!("{:?} is in non-existent deleted hunk", range.end)
4105                };
4106
4107                let mut suffix = base_text
4108                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4109                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4110                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4111                }
4112                suffix
4113            }
4114        };
4115
4116        result.add_assign(&suffix);
4117        result
4118    }
4119
4120    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4121    where
4122        D: TextDimension,
4123    {
4124        let mut summary = D::zero(());
4125        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4126        cursor.seek(&range.start, Bias::Right);
4127        if let Some(excerpt) = cursor.item() {
4128            let mut end_before_newline = cursor.end();
4129            if excerpt.has_trailing_newline {
4130                end_before_newline -= ExcerptOffset::new(1);
4131            }
4132
4133            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4134            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4135            let end_in_excerpt =
4136                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4137            summary.add_assign(
4138                &excerpt
4139                    .buffer
4140                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4141            );
4142
4143            if range.end > end_before_newline {
4144                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4145            }
4146
4147            cursor.next();
4148        }
4149
4150        if range.end > *cursor.start() {
4151            summary.add_assign(
4152                &cursor
4153                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4154                    .0,
4155            );
4156            if let Some(excerpt) = cursor.item() {
4157                range.end = cmp::max(*cursor.start(), range.end);
4158
4159                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4160                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4161                summary.add_assign(
4162                    &excerpt
4163                        .buffer
4164                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4165                );
4166            }
4167        }
4168
4169        summary
4170    }
4171
4172    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4173    where
4174        D: TextDimension + Ord + Sub<D, Output = D>,
4175    {
4176        self.summaries_for_anchors([anchor])[0]
4177    }
4178
4179    fn resolve_summary_for_anchor<D>(
4180        &self,
4181        anchor: &Anchor,
4182        excerpt_position: D,
4183        diff_transforms: &mut Cursor<
4184            DiffTransform,
4185            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4186        >,
4187    ) -> D
4188    where
4189        D: TextDimension + Ord + Sub<D, Output = D>,
4190    {
4191        loop {
4192            let transform_end_position = diff_transforms.end().0.0;
4193            let at_transform_end =
4194                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4195            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4196                diff_transforms.next();
4197                continue;
4198            }
4199
4200            let mut position = diff_transforms.start().1.0;
4201            match diff_transforms.item() {
4202                Some(DiffTransform::DeletedHunk {
4203                    buffer_id,
4204                    base_text_byte_range,
4205                    ..
4206                }) => {
4207                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4208                        && let Some(base_text) =
4209                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4210                        && base_text.can_resolve(diff_base_anchor)
4211                    {
4212                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4213                        if base_text_offset >= base_text_byte_range.start
4214                            && base_text_offset <= base_text_byte_range.end
4215                        {
4216                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4217                                base_text_byte_range.start..base_text_offset,
4218                            );
4219                            position.add_assign(&position_in_hunk);
4220                        } else if at_transform_end {
4221                            diff_transforms.next();
4222                            continue;
4223                        }
4224                    }
4225                }
4226                _ => {
4227                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4228                        diff_transforms.next();
4229                        continue;
4230                    }
4231                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4232                    position.add_assign(&overshoot);
4233                }
4234            }
4235
4236            return position;
4237        }
4238    }
4239
4240    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4241        let mut cursor = self
4242            .excerpts
4243            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
4244        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4245
4246        cursor.seek(&Some(locator), Bias::Left);
4247        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
4248            cursor.prev();
4249        }
4250
4251        let mut position = cursor.start().1;
4252        if let Some(excerpt) = cursor.item()
4253            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
4254        {
4255            let excerpt_buffer_start = excerpt
4256                .buffer
4257                .offset_for_anchor(&excerpt.range.context.start);
4258            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4259            let buffer_position = cmp::min(
4260                excerpt_buffer_end,
4261                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4262            );
4263            if buffer_position > excerpt_buffer_start {
4264                position.value += buffer_position - excerpt_buffer_start;
4265            }
4266        }
4267        position
4268    }
4269
4270    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4271        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4272            excerpt_id = *replacement;
4273        }
4274        excerpt_id
4275    }
4276
4277    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4278    where
4279        D: TextDimension + Ord + Sub<D, Output = D>,
4280        I: 'a + IntoIterator<Item = &'a Anchor>,
4281    {
4282        let mut anchors = anchors.into_iter().peekable();
4283        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4284        let mut diff_transforms_cursor = self
4285            .diff_transforms
4286            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(());
4287        diff_transforms_cursor.next();
4288
4289        let mut summaries = Vec::new();
4290        while let Some(anchor) = anchors.peek() {
4291            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4292
4293            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
4294                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
4295            });
4296
4297            let locator = self.excerpt_locator_for_id(excerpt_id);
4298            cursor.seek_forward(locator, Bias::Left);
4299            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
4300                cursor.prev();
4301            }
4302
4303            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4304            if let Some(excerpt) = cursor.item() {
4305                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4306                    let position = self.resolve_summary_for_anchor(
4307                        &Anchor::min(),
4308                        excerpt_start_position,
4309                        &mut diff_transforms_cursor,
4310                    );
4311                    summaries.extend(excerpt_anchors.map(|_| position));
4312                    continue;
4313                }
4314                let excerpt_buffer_start =
4315                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4316                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4317                for (buffer_summary, anchor) in excerpt
4318                    .buffer
4319                    .summaries_for_anchors_with_payload::<D, _, _>(
4320                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4321                    )
4322                {
4323                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4324                    let mut position = excerpt_start_position;
4325                    if summary > excerpt_buffer_start {
4326                        position.add_assign(&(summary - excerpt_buffer_start));
4327                    }
4328
4329                    if position > diff_transforms_cursor.start().0.0 {
4330                        diff_transforms_cursor
4331                            .seek_forward(&ExcerptDimension(position), Bias::Left);
4332                    }
4333
4334                    summaries.push(self.resolve_summary_for_anchor(
4335                        anchor,
4336                        position,
4337                        &mut diff_transforms_cursor,
4338                    ));
4339                }
4340            } else {
4341                diff_transforms_cursor
4342                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
4343                let position = self.resolve_summary_for_anchor(
4344                    &Anchor::max(),
4345                    excerpt_start_position,
4346                    &mut diff_transforms_cursor,
4347                );
4348                summaries.extend(excerpt_anchors.map(|_| position));
4349            }
4350        }
4351
4352        summaries
4353    }
4354
4355    pub fn dimensions_from_points<'a, D>(
4356        &'a self,
4357        points: impl 'a + IntoIterator<Item = Point>,
4358    ) -> impl 'a + Iterator<Item = D>
4359    where
4360        D: TextDimension + Sub<D, Output = D>,
4361    {
4362        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4363        cursor.seek(&DimensionPair {
4364            key: Point::default(),
4365            value: None,
4366        });
4367        let mut points = points.into_iter();
4368        iter::from_fn(move || {
4369            let point = points.next()?;
4370
4371            cursor.seek_forward(&DimensionPair {
4372                key: point,
4373                value: None,
4374            });
4375
4376            if let Some(region) = cursor.region() {
4377                let overshoot = point - region.range.start.key;
4378                let buffer_point = region.buffer_range.start.key + overshoot;
4379                let mut position = region.range.start.value.unwrap();
4380                position.add_assign(
4381                    &region
4382                        .buffer
4383                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4384                );
4385                if point == region.range.end.key && region.has_trailing_newline {
4386                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4387                }
4388                Some(position)
4389            } else {
4390                Some(D::from_text_summary(&self.text_summary()))
4391            }
4392        })
4393    }
4394
4395    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4396    where
4397        I: 'a + IntoIterator<Item = &'a Anchor>,
4398    {
4399        let mut anchors = anchors.into_iter().enumerate().peekable();
4400        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4401        cursor.next();
4402
4403        let mut result = Vec::new();
4404
4405        while let Some((_, anchor)) = anchors.peek() {
4406            let old_excerpt_id = anchor.excerpt_id;
4407
4408            // Find the location where this anchor's excerpt should be.
4409            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4410            cursor.seek_forward(&Some(old_locator), Bias::Left);
4411
4412            let next_excerpt = cursor.item();
4413            let prev_excerpt = cursor.prev_item();
4414
4415            // Process all of the anchors for this excerpt.
4416            while let Some((anchor_ix, &anchor)) =
4417                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
4418            {
4419                let mut anchor = anchor;
4420
4421                // Leave min and max anchors unchanged if invalid or
4422                // if the old excerpt still exists at this location
4423                let mut kept_position = next_excerpt
4424                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
4425                    || old_excerpt_id == ExcerptId::max()
4426                    || old_excerpt_id == ExcerptId::min();
4427
4428                // If the old excerpt no longer exists at this location, then attempt to
4429                // find an equivalent position for this anchor in an adjacent excerpt.
4430                if !kept_position {
4431                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4432                        if excerpt.contains(&anchor) {
4433                            anchor.excerpt_id = excerpt.id;
4434                            kept_position = true;
4435                            break;
4436                        }
4437                    }
4438                }
4439
4440                // If there's no adjacent excerpt that contains the anchor's position,
4441                // then report that the anchor has lost its position.
4442                if !kept_position {
4443                    anchor = if let Some(excerpt) = next_excerpt {
4444                        let mut text_anchor = excerpt
4445                            .range
4446                            .context
4447                            .start
4448                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4449                        if text_anchor
4450                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4451                            .is_gt()
4452                        {
4453                            text_anchor = excerpt.range.context.end;
4454                        }
4455                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4456                    } else if let Some(excerpt) = prev_excerpt {
4457                        let mut text_anchor = excerpt
4458                            .range
4459                            .context
4460                            .end
4461                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4462                        if text_anchor
4463                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4464                            .is_lt()
4465                        {
4466                            text_anchor = excerpt.range.context.start;
4467                        }
4468                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4469                    } else if anchor.text_anchor.bias == Bias::Left {
4470                        Anchor::min()
4471                    } else {
4472                        Anchor::max()
4473                    };
4474                }
4475
4476                result.push((anchor_ix, anchor, kept_position));
4477            }
4478        }
4479        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4480        result
4481    }
4482
4483    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4484        self.anchor_at(position, Bias::Left)
4485    }
4486
4487    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4488        self.anchor_at(position, Bias::Right)
4489    }
4490
4491    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4492        let offset = position.to_offset(self);
4493
4494        // Find the given position in the diff transforms. Determine the corresponding
4495        // offset in the excerpts, and whether the position is within a deleted hunk.
4496        let mut diff_transforms = self
4497            .diff_transforms
4498            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4499        diff_transforms.seek(&offset, Bias::Right);
4500
4501        if offset == diff_transforms.start().0
4502            && bias == Bias::Left
4503            && let Some(prev_item) = diff_transforms.prev_item()
4504            && let DiffTransform::DeletedHunk { .. } = prev_item
4505        {
4506            diff_transforms.prev();
4507        }
4508        let offset_in_transform = offset - diff_transforms.start().0;
4509        let mut excerpt_offset = diff_transforms.start().1;
4510        let mut diff_base_anchor = None;
4511        if let Some(DiffTransform::DeletedHunk {
4512            buffer_id,
4513            base_text_byte_range,
4514            has_trailing_newline,
4515            ..
4516        }) = diff_transforms.item()
4517        {
4518            let diff = self.diffs.get(buffer_id).expect("missing diff");
4519            if offset_in_transform > base_text_byte_range.len() {
4520                debug_assert!(*has_trailing_newline);
4521                bias = Bias::Right;
4522            } else {
4523                diff_base_anchor = Some(
4524                    diff.base_text()
4525                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4526                );
4527                bias = Bias::Left;
4528            }
4529        } else {
4530            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4531        };
4532
4533        let mut excerpts = self
4534            .excerpts
4535            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
4536        excerpts.seek(&excerpt_offset, Bias::Right);
4537        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4538            excerpts.prev();
4539        }
4540        if let Some(excerpt) = excerpts.item() {
4541            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4542            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
4543                overshoot -= 1;
4544                bias = Bias::Right;
4545            }
4546
4547            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4548            let text_anchor =
4549                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4550            let anchor = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor);
4551            match diff_base_anchor {
4552                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
4553                None => anchor,
4554            }
4555        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4556            Anchor::min()
4557        } else {
4558            Anchor::max()
4559        }
4560    }
4561
4562    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
4563    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
4564        let (excerpt, buffer, _) = self.as_singleton()?;
4565        Some(Anchor::in_buffer(*excerpt, buffer, text_anchor))
4566    }
4567
4568    /// Returns an anchor for the given excerpt and text anchor,
4569    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4570    pub fn anchor_range_in_excerpt(
4571        &self,
4572        excerpt_id: ExcerptId,
4573        text_anchor: Range<text::Anchor>,
4574    ) -> Option<Range<Anchor>> {
4575        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4576        let excerpt = self.excerpt(excerpt_id)?;
4577
4578        Some(
4579            self.anchor_in_excerpt_(excerpt, text_anchor.start)?
4580                ..self.anchor_in_excerpt_(excerpt, text_anchor.end)?,
4581        )
4582    }
4583
4584    /// Returns an anchor for the given excerpt and text anchor,
4585    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4586    pub fn anchor_in_excerpt(
4587        &self,
4588        excerpt_id: ExcerptId,
4589        text_anchor: text::Anchor,
4590    ) -> Option<Anchor> {
4591        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4592        let excerpt = self.excerpt(excerpt_id)?;
4593        self.anchor_in_excerpt_(excerpt, text_anchor)
4594    }
4595
4596    fn anchor_in_excerpt_(&self, excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
4597        match text_anchor.buffer_id {
4598            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
4599            Some(_) => return None,
4600            None if text_anchor == text::Anchor::MAX || text_anchor == text::Anchor::MIN => {
4601                return Some(Anchor::in_buffer(
4602                    excerpt.id,
4603                    excerpt.buffer_id,
4604                    text_anchor,
4605                ));
4606            }
4607            None => return None,
4608        }
4609
4610        let context = &excerpt.range.context;
4611        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
4612            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
4613        {
4614            return None;
4615        }
4616
4617        Some(Anchor::in_buffer(
4618            excerpt.id,
4619            excerpt.buffer_id,
4620            text_anchor,
4621        ))
4622    }
4623
4624    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4625        Some(self.excerpt(excerpt_id)?.range.context.clone())
4626    }
4627
4628    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4629        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4630            true
4631        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4632            excerpt.buffer.can_resolve(&anchor.text_anchor)
4633        } else {
4634            false
4635        }
4636    }
4637
4638    pub fn excerpts(
4639        &self,
4640    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4641        self.excerpts
4642            .iter()
4643            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4644    }
4645
4646    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
4647        let excerpts = self.excerpts.cursor(());
4648        let diff_transforms = self.diff_transforms.cursor(());
4649        MultiBufferCursor {
4650            excerpts,
4651            diff_transforms,
4652            diffs: &self.diffs,
4653            cached_region: None,
4654        }
4655    }
4656
4657    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4658        let start_locator = self.excerpt_locator_for_id(excerpt_id);
4659        let mut excerpts = self
4660            .excerpts
4661            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(());
4662        excerpts.seek(&Some(start_locator), Bias::Left);
4663        excerpts.prev();
4664
4665        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(());
4666        diff_transforms.seek(&excerpts.start().1, Bias::Left);
4667        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
4668            diff_transforms.next();
4669        }
4670
4671        let excerpt = excerpts.item()?;
4672        Some(MultiBufferExcerpt {
4673            excerpt,
4674            offset: diff_transforms.start().output_dimension.0,
4675            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4676            excerpt_offset: excerpts.start().1.clone(),
4677            diff_transforms,
4678        })
4679    }
4680
4681    pub fn excerpt_boundaries_in_range<R, T>(
4682        &self,
4683        range: R,
4684    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4685    where
4686        R: RangeBounds<T>,
4687        T: ToOffset,
4688    {
4689        let start_offset;
4690        let start = match range.start_bound() {
4691            Bound::Included(start) => {
4692                start_offset = start.to_offset(self);
4693                Bound::Included(start_offset)
4694            }
4695            Bound::Excluded(_) => {
4696                panic!("not supported")
4697            }
4698            Bound::Unbounded => {
4699                start_offset = 0;
4700                Bound::Unbounded
4701            }
4702        };
4703        let end = match range.end_bound() {
4704            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4705            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4706            Bound::Unbounded => Bound::Unbounded,
4707        };
4708        let bounds = (start, end);
4709
4710        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4711        cursor.seek(&DimensionPair {
4712            key: start_offset,
4713            value: None,
4714        });
4715
4716        if cursor
4717            .region()
4718            .is_some_and(|region| bounds.contains(&region.range.start.key))
4719        {
4720            cursor.prev_excerpt();
4721        } else {
4722            cursor.seek_to_start_of_current_excerpt();
4723        }
4724        let mut prev_region = cursor.region();
4725
4726        cursor.next_excerpt();
4727
4728        iter::from_fn(move || {
4729            loop {
4730                if self.singleton {
4731                    return None;
4732                }
4733
4734                let next_region = cursor.region()?;
4735                cursor.next_excerpt();
4736                if !bounds.contains(&next_region.range.start.key) {
4737                    prev_region = Some(next_region);
4738                    continue;
4739                }
4740
4741                let next_region_start = next_region.range.start.value.unwrap();
4742                let next_region_end = if let Some(region) = cursor.region() {
4743                    region.range.start.value.unwrap()
4744                } else {
4745                    self.max_point()
4746                };
4747
4748                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4749                    id: region.excerpt.id,
4750                    buffer: region.excerpt.buffer.clone(),
4751                    buffer_id: region.excerpt.buffer_id,
4752                    range: region.excerpt.range.clone(),
4753                    end_row: MultiBufferRow(next_region_start.row),
4754                });
4755
4756                let next = ExcerptInfo {
4757                    id: next_region.excerpt.id,
4758                    buffer: next_region.excerpt.buffer.clone(),
4759                    buffer_id: next_region.excerpt.buffer_id,
4760                    range: next_region.excerpt.range.clone(),
4761                    end_row: if next_region.excerpt.has_trailing_newline {
4762                        MultiBufferRow(next_region_end.row - 1)
4763                    } else {
4764                        MultiBufferRow(next_region_end.row)
4765                    },
4766                };
4767
4768                let row = MultiBufferRow(next_region_start.row);
4769
4770                prev_region = Some(next_region);
4771
4772                return Some(ExcerptBoundary { row, prev, next });
4773            }
4774        })
4775    }
4776
4777    pub fn edit_count(&self) -> usize {
4778        self.edit_count
4779    }
4780
4781    pub fn non_text_state_update_count(&self) -> usize {
4782        self.non_text_state_update_count
4783    }
4784
4785    /// Returns the smallest enclosing bracket ranges containing the given range or
4786    /// None if no brackets contain range or the range is not contained in a single
4787    /// excerpt
4788    ///
4789    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4790    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4791        &self,
4792        range: Range<T>,
4793        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4794    ) -> Option<(Range<usize>, Range<usize>)> {
4795        let range = range.start.to_offset(self)..range.end.to_offset(self);
4796        let mut excerpt = self.excerpt_containing(range.clone())?;
4797        let buffer = excerpt.buffer();
4798        let excerpt_buffer_range = excerpt.buffer_range();
4799
4800        // Filter to ranges contained in the excerpt
4801        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4802            excerpt_buffer_range.contains(&open.start)
4803                && excerpt_buffer_range.contains(&close.end)
4804                && range_filter.is_none_or(|filter| filter(buffer, open, close))
4805        };
4806
4807        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4808            excerpt.map_range_to_buffer(range),
4809            Some(&range_filter),
4810        )?;
4811
4812        Some((
4813            excerpt.map_range_from_buffer(open),
4814            excerpt.map_range_from_buffer(close),
4815        ))
4816    }
4817
4818    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4819    /// not contained in a single excerpt
4820    pub fn enclosing_bracket_ranges<T: ToOffset>(
4821        &self,
4822        range: Range<T>,
4823    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4824        let range = range.start.to_offset(self)..range.end.to_offset(self);
4825        let mut excerpt = self.excerpt_containing(range.clone())?;
4826
4827        Some(
4828            excerpt
4829                .buffer()
4830                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
4831                .filter_map(move |pair| {
4832                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
4833                        Some((
4834                            excerpt.map_range_from_buffer(pair.open_range),
4835                            excerpt.map_range_from_buffer(pair.close_range),
4836                        ))
4837                    } else {
4838                        None
4839                    }
4840                }),
4841        )
4842    }
4843
4844    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4845    /// not contained in a single excerpt
4846    pub fn text_object_ranges<T: ToOffset>(
4847        &self,
4848        range: Range<T>,
4849        options: TreeSitterOptions,
4850    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
4851        let range = range.start.to_offset(self)..range.end.to_offset(self);
4852        self.excerpt_containing(range.clone())
4853            .map(|mut excerpt| {
4854                excerpt
4855                    .buffer()
4856                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
4857                    .filter_map(move |(range, text_object)| {
4858                        if excerpt.contains_buffer_range(range.clone()) {
4859                            Some((excerpt.map_range_from_buffer(range), text_object))
4860                        } else {
4861                            None
4862                        }
4863                    })
4864            })
4865            .into_iter()
4866            .flatten()
4867    }
4868
4869    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
4870    /// not contained in a single excerpt
4871    pub fn bracket_ranges<T: ToOffset>(
4872        &self,
4873        range: Range<T>,
4874    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
4875        let range = range.start.to_offset(self)..range.end.to_offset(self);
4876        let mut excerpt = self.excerpt_containing(range.clone())?;
4877
4878        Some(
4879            excerpt
4880                .buffer()
4881                .bracket_ranges(excerpt.map_range_to_buffer(range))
4882                .filter_map(move |pair| {
4883                    let buffer_range = pair.open_range.start..pair.close_range.end;
4884                    if excerpt.contains_buffer_range(buffer_range) {
4885                        Some((
4886                            excerpt.map_range_from_buffer(pair.open_range),
4887                            excerpt.map_range_from_buffer(pair.close_range),
4888                        ))
4889                    } else {
4890                        None
4891                    }
4892                }),
4893        )
4894    }
4895
4896    pub fn redacted_ranges<'a, T: ToOffset>(
4897        &'a self,
4898        range: Range<T>,
4899        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
4900    ) -> impl Iterator<Item = Range<usize>> + 'a {
4901        let range = range.start.to_offset(self)..range.end.to_offset(self);
4902        self.lift_buffer_metadata(range, move |buffer, range| {
4903            if redaction_enabled(buffer.file()) {
4904                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
4905            } else {
4906                None
4907            }
4908        })
4909        .map(|(range, _, _)| range)
4910    }
4911
4912    pub fn runnable_ranges(
4913        &self,
4914        range: Range<Anchor>,
4915    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
4916        let range = range.start.to_offset(self)..range.end.to_offset(self);
4917        self.lift_buffer_metadata(range, move |buffer, range| {
4918            Some(
4919                buffer
4920                    .runnable_ranges(range.clone())
4921                    .filter(move |runnable| {
4922                        runnable.run_range.start >= range.start
4923                            && runnable.run_range.end < range.end
4924                    })
4925                    .map(|runnable| (runnable.run_range.clone(), runnable)),
4926            )
4927        })
4928        .map(|(run_range, runnable, _)| language::RunnableRange {
4929            run_range,
4930            ..runnable
4931        })
4932    }
4933
4934    pub fn line_indents(
4935        &self,
4936        start_row: MultiBufferRow,
4937        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
4938    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
4939        let max_point = self.max_point();
4940        let mut cursor = self.cursor::<Point>();
4941        cursor.seek(&Point::new(start_row.0, 0));
4942        iter::from_fn(move || {
4943            let mut region = cursor.region()?;
4944            while !buffer_filter(&region.excerpt.buffer) {
4945                cursor.next();
4946                region = cursor.region()?;
4947            }
4948            let overshoot = start_row.0.saturating_sub(region.range.start.row);
4949            let buffer_start_row =
4950                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
4951
4952            let buffer_end_row = if region.is_main_buffer
4953                && (region.has_trailing_newline || region.range.end == max_point)
4954            {
4955                region.buffer_range.end.row
4956            } else {
4957                region.buffer_range.end.row.saturating_sub(1)
4958            };
4959
4960            let line_indents = region
4961                .buffer
4962                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
4963            cursor.next();
4964            Some(line_indents.map(move |(buffer_row, indent)| {
4965                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
4966                (MultiBufferRow(row), indent, &region.excerpt.buffer)
4967            }))
4968        })
4969        .flatten()
4970    }
4971
4972    pub fn reversed_line_indents(
4973        &self,
4974        end_row: MultiBufferRow,
4975        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
4976    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
4977        let max_point = self.max_point();
4978        let mut cursor = self.cursor::<Point>();
4979        cursor.seek(&Point::new(end_row.0, 0));
4980        iter::from_fn(move || {
4981            let mut region = cursor.region()?;
4982            while !buffer_filter(&region.excerpt.buffer) {
4983                cursor.prev();
4984                region = cursor.region()?;
4985            }
4986
4987            let buffer_start_row = region.buffer_range.start.row;
4988            let buffer_end_row = if region.is_main_buffer
4989                && (region.has_trailing_newline || region.range.end == max_point)
4990            {
4991                region.buffer_range.end.row + 1
4992            } else {
4993                region.buffer_range.end.row
4994            };
4995
4996            let overshoot = end_row.0 - region.range.start.row;
4997            let buffer_end_row =
4998                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
4999
5000            let line_indents = region
5001                .buffer
5002                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5003            cursor.prev();
5004            Some(line_indents.map(move |(buffer_row, indent)| {
5005                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5006                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5007            }))
5008        })
5009        .flatten()
5010    }
5011
5012    pub async fn enclosing_indent(
5013        &self,
5014        mut target_row: MultiBufferRow,
5015    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5016        let max_row = MultiBufferRow(self.max_point().row);
5017        if target_row >= max_row {
5018            return None;
5019        }
5020
5021        let mut target_indent = self.line_indent_for_row(target_row);
5022
5023        // If the current row is at the start of an indented block, we want to return this
5024        // block as the enclosing indent.
5025        if !target_indent.is_line_empty() && target_row < max_row {
5026            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5027            if !next_line_indent.is_line_empty()
5028                && target_indent.raw_len() < next_line_indent.raw_len()
5029            {
5030                target_indent = next_line_indent;
5031                target_row.0 += 1;
5032            }
5033        }
5034
5035        const SEARCH_ROW_LIMIT: u32 = 25000;
5036        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5037        const YIELD_INTERVAL: u32 = 100;
5038
5039        let mut accessed_row_counter = 0;
5040
5041        // If there is a blank line at the current row, search for the next non indented lines
5042        if target_indent.is_line_empty() {
5043            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5044            let end =
5045                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5046
5047            let mut non_empty_line_above = None;
5048            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5049                if row < start {
5050                    break;
5051                }
5052                accessed_row_counter += 1;
5053                if accessed_row_counter == YIELD_INTERVAL {
5054                    accessed_row_counter = 0;
5055                    yield_now().await;
5056                }
5057                if !indent.is_line_empty() {
5058                    non_empty_line_above = Some((row, indent));
5059                    break;
5060                }
5061            }
5062
5063            let mut non_empty_line_below = None;
5064            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5065                if row > end {
5066                    break;
5067                }
5068                accessed_row_counter += 1;
5069                if accessed_row_counter == YIELD_INTERVAL {
5070                    accessed_row_counter = 0;
5071                    yield_now().await;
5072                }
5073                if !indent.is_line_empty() {
5074                    non_empty_line_below = Some((row, indent));
5075                    break;
5076                }
5077            }
5078
5079            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5080                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5081                    if above_indent.raw_len() >= below_indent.raw_len() {
5082                        (above_row, above_indent)
5083                    } else {
5084                        (below_row, below_indent)
5085                    }
5086                }
5087                (Some(above), None) => above,
5088                (None, Some(below)) => below,
5089                _ => return None,
5090            };
5091
5092            target_indent = indent;
5093            target_row = row;
5094        }
5095
5096        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5097        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5098
5099        let mut start_indent = None;
5100        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5101            if row < start {
5102                break;
5103            }
5104            accessed_row_counter += 1;
5105            if accessed_row_counter == YIELD_INTERVAL {
5106                accessed_row_counter = 0;
5107                yield_now().await;
5108            }
5109            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5110                start_indent = Some((row, indent));
5111                break;
5112            }
5113        }
5114        let (start_row, start_indent_size) = start_indent?;
5115
5116        let mut end_indent = (end, None);
5117        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5118            if row > end {
5119                break;
5120            }
5121            accessed_row_counter += 1;
5122            if accessed_row_counter == YIELD_INTERVAL {
5123                accessed_row_counter = 0;
5124                yield_now().await;
5125            }
5126            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5127                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5128                break;
5129            }
5130        }
5131        let (end_row, end_indent_size) = end_indent;
5132
5133        let indent = if let Some(end_indent_size) = end_indent_size {
5134            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5135                start_indent_size
5136            } else {
5137                end_indent_size
5138            }
5139        } else {
5140            start_indent_size
5141        };
5142
5143        Some((start_row..end_row, indent))
5144    }
5145
5146    pub fn indent_guides_in_range<T: ToPoint>(
5147        &self,
5148        range: Range<T>,
5149        ignore_disabled_for_language: bool,
5150        cx: &App,
5151    ) -> impl Iterator<Item = IndentGuide> {
5152        let range = range.start.to_point(self)..range.end.to_point(self);
5153        let start_row = MultiBufferRow(range.start.row);
5154        let end_row = MultiBufferRow(range.end.row);
5155
5156        let mut row_indents = self.line_indents(start_row, |buffer| {
5157            let settings =
5158                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5159            settings.indent_guides.enabled || ignore_disabled_for_language
5160        });
5161
5162        let mut result = Vec::new();
5163        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5164
5165        let mut prev_settings = None;
5166        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5167            if first_row > end_row {
5168                break;
5169            }
5170            let current_depth = indent_stack.len() as u32;
5171
5172            // Avoid retrieving the language settings repeatedly for every buffer row.
5173            if let Some((prev_buffer_id, _)) = &prev_settings
5174                && prev_buffer_id != &buffer.remote_id()
5175            {
5176                prev_settings.take();
5177            }
5178            let settings = &prev_settings
5179                .get_or_insert_with(|| {
5180                    (
5181                        buffer.remote_id(),
5182                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5183                    )
5184                })
5185                .1;
5186            let tab_size = settings.tab_size.get();
5187
5188            // When encountering empty, continue until found useful line indent
5189            // then add to the indent stack with the depth found
5190            let mut found_indent = false;
5191            let mut last_row = first_row;
5192            if line_indent.is_line_blank() {
5193                while !found_indent {
5194                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5195                        break;
5196                    };
5197                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5198                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5199                        break;
5200                    }
5201
5202                    if new_line_indent.is_line_blank() {
5203                        continue;
5204                    }
5205                    last_row = target_row.min(end_row);
5206                    line_indent = new_line_indent;
5207                    found_indent = true;
5208                    break;
5209                }
5210            } else {
5211                found_indent = true
5212            }
5213
5214            let depth = if found_indent {
5215                line_indent.len(tab_size) / tab_size
5216            } else {
5217                0
5218            };
5219
5220            match depth.cmp(&current_depth) {
5221                cmp::Ordering::Less => {
5222                    for _ in 0..(current_depth - depth) {
5223                        let mut indent = indent_stack.pop().unwrap();
5224                        if last_row != first_row {
5225                            // In this case, we landed on an empty row, had to seek forward,
5226                            // and discovered that the indent we where on is ending.
5227                            // This means that the last display row must
5228                            // be on line that ends this indent range, so we
5229                            // should display the range up to the first non-empty line
5230                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5231                        }
5232
5233                        result.push(indent)
5234                    }
5235                }
5236                cmp::Ordering::Greater => {
5237                    for next_depth in current_depth..depth {
5238                        indent_stack.push(IndentGuide {
5239                            buffer_id: buffer.remote_id(),
5240                            start_row: first_row,
5241                            end_row: last_row,
5242                            depth: next_depth,
5243                            tab_size,
5244                            settings: settings.indent_guides.clone(),
5245                        });
5246                    }
5247                }
5248                _ => {}
5249            }
5250
5251            for indent in indent_stack.iter_mut() {
5252                indent.end_row = last_row;
5253            }
5254        }
5255
5256        result.extend(indent_stack);
5257        result.into_iter()
5258    }
5259
5260    pub fn trailing_excerpt_update_count(&self) -> usize {
5261        self.trailing_excerpt_update_count
5262    }
5263
5264    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5265        self.point_to_buffer_offset(point)
5266            .and_then(|(buffer, _)| buffer.file())
5267    }
5268
5269    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5270        self.point_to_buffer_offset(point)
5271            .and_then(|(buffer, offset)| buffer.language_at(offset))
5272    }
5273
5274    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5275        self.excerpts
5276            .first()
5277            .map(|excerpt| &excerpt.buffer)
5278            .map(|buffer| {
5279                language_settings(
5280                    buffer.language().map(|language| language.name()),
5281                    buffer.file(),
5282                    cx,
5283                )
5284            })
5285            .unwrap_or_else(move || self.language_settings_at(0, cx))
5286    }
5287
5288    pub fn language_settings_at<'a, T: ToOffset>(
5289        &'a self,
5290        point: T,
5291        cx: &'a App,
5292    ) -> Cow<'a, LanguageSettings> {
5293        let mut language = None;
5294        let mut file = None;
5295        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5296            language = buffer.language_at(offset);
5297            file = buffer.file();
5298        }
5299        language_settings(language.map(|l| l.name()), file, cx)
5300    }
5301
5302    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5303        self.point_to_buffer_offset(point)
5304            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5305    }
5306
5307    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5308        self.point_to_buffer_offset(point)
5309            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5310            .unwrap_or_default()
5311    }
5312
5313    pub fn language_indent_size_at<T: ToOffset>(
5314        &self,
5315        position: T,
5316        cx: &App,
5317    ) -> Option<IndentSize> {
5318        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5319        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5320    }
5321
5322    pub fn is_dirty(&self) -> bool {
5323        self.is_dirty
5324    }
5325
5326    pub fn has_deleted_file(&self) -> bool {
5327        self.has_deleted_file
5328    }
5329
5330    pub fn has_conflict(&self) -> bool {
5331        self.has_conflict
5332    }
5333
5334    pub fn has_diagnostics(&self) -> bool {
5335        self.excerpts
5336            .iter()
5337            .any(|excerpt| excerpt.buffer.has_diagnostics())
5338    }
5339
5340    pub fn diagnostic_group(
5341        &self,
5342        buffer_id: BufferId,
5343        group_id: usize,
5344    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
5345        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
5346            if buffer.remote_id() != buffer_id {
5347                return None;
5348            };
5349            Some(
5350                buffer
5351                    .diagnostics_in_range(range, false)
5352                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
5353                    .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
5354            )
5355        })
5356        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5357    }
5358
5359    pub fn diagnostics_in_range<'a, T>(
5360        &'a self,
5361        range: Range<T>,
5362    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, T>> + 'a
5363    where
5364        T: 'a
5365            + text::ToOffset
5366            + text::FromAnchor
5367            + TextDimension
5368            + Ord
5369            + Sub<T, Output = T>
5370            + fmt::Debug,
5371    {
5372        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5373            Some(
5374                buffer
5375                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5376                    .map(|entry| (entry.range, entry.diagnostic)),
5377            )
5378        })
5379        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5380    }
5381
5382    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
5383        &'a self,
5384        range: Range<T>,
5385    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, T>)> + 'a
5386    where
5387        T: 'a
5388            + text::ToOffset
5389            + text::FromAnchor
5390            + TextDimension
5391            + Ord
5392            + Sub<T, Output = T>
5393            + fmt::Debug,
5394    {
5395        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5396            Some(
5397                buffer
5398                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5399                    .map(|entry| (entry.range, entry.diagnostic)),
5400            )
5401        })
5402        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
5403    }
5404
5405    pub fn syntax_ancestor<T: ToOffset>(
5406        &self,
5407        range: Range<T>,
5408    ) -> Option<(tree_sitter::Node<'_>, Range<usize>)> {
5409        let range = range.start.to_offset(self)..range.end.to_offset(self);
5410        let mut excerpt = self.excerpt_containing(range.clone())?;
5411        let node = excerpt
5412            .buffer()
5413            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5414        let node_range = node.byte_range();
5415        if !excerpt.contains_buffer_range(node_range.clone()) {
5416            return None;
5417        };
5418        Some((node, excerpt.map_range_from_buffer(node_range)))
5419    }
5420
5421    pub fn syntax_next_sibling<T: ToOffset>(
5422        &self,
5423        range: Range<T>,
5424    ) -> Option<tree_sitter::Node<'_>> {
5425        let range = range.start.to_offset(self)..range.end.to_offset(self);
5426        let mut excerpt = self.excerpt_containing(range.clone())?;
5427        excerpt
5428            .buffer()
5429            .syntax_next_sibling(excerpt.map_range_to_buffer(range))
5430    }
5431
5432    pub fn syntax_prev_sibling<T: ToOffset>(
5433        &self,
5434        range: Range<T>,
5435    ) -> Option<tree_sitter::Node<'_>> {
5436        let range = range.start.to_offset(self)..range.end.to_offset(self);
5437        let mut excerpt = self.excerpt_containing(range.clone())?;
5438        excerpt
5439            .buffer()
5440            .syntax_prev_sibling(excerpt.map_range_to_buffer(range))
5441    }
5442
5443    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5444        let (excerpt_id, _, buffer) = self.as_singleton()?;
5445        let outline = buffer.outline(theme);
5446        Some(Outline::new(
5447            outline
5448                .items
5449                .into_iter()
5450                .flat_map(|item| {
5451                    Some(OutlineItem {
5452                        depth: item.depth,
5453                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
5454                        text: item.text,
5455                        highlight_ranges: item.highlight_ranges,
5456                        name_ranges: item.name_ranges,
5457                        body_range: item.body_range.and_then(|body_range| {
5458                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
5459                        }),
5460                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5461                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
5462                        }),
5463                    })
5464                })
5465                .collect(),
5466        ))
5467    }
5468
5469    pub fn symbols_containing<T: ToOffset>(
5470        &self,
5471        offset: T,
5472        theme: Option<&SyntaxTheme>,
5473    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5474        let anchor = self.anchor_before(offset);
5475        let excerpt_id = anchor.excerpt_id;
5476        let excerpt = self.excerpt(excerpt_id)?;
5477        let buffer_id = excerpt.buffer_id;
5478        Some((
5479            buffer_id,
5480            excerpt
5481                .buffer
5482                .symbols_containing(anchor.text_anchor, theme)
5483                .into_iter()
5484                .flat_map(|item| {
5485                    Some(OutlineItem {
5486                        depth: item.depth,
5487                        range: Anchor::range_in_buffer(excerpt_id, buffer_id, item.range),
5488                        text: item.text,
5489                        highlight_ranges: item.highlight_ranges,
5490                        name_ranges: item.name_ranges,
5491                        body_range: item.body_range.map(|body_range| {
5492                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5493                        }),
5494                        annotation_range: item.annotation_range.map(|body_range| {
5495                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5496                        }),
5497                    })
5498                })
5499                .collect(),
5500        ))
5501    }
5502
5503    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5504        if id == ExcerptId::min() {
5505            Locator::min_ref()
5506        } else if id == ExcerptId::max() {
5507            Locator::max_ref()
5508        } else {
5509            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
5510            if let Some(entry) = item
5511                && entry.id == id
5512            {
5513                return &entry.locator;
5514            }
5515            panic!("invalid excerpt id {id:?}")
5516        }
5517    }
5518
5519    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5520    fn excerpt_locators_for_ids(
5521        &self,
5522        ids: impl IntoIterator<Item = ExcerptId>,
5523    ) -> SmallVec<[Locator; 1]> {
5524        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5525        sorted_ids.sort_unstable();
5526        sorted_ids.dedup();
5527        let mut locators = SmallVec::new();
5528
5529        while sorted_ids.last() == Some(&ExcerptId::max()) {
5530            sorted_ids.pop();
5531            locators.push(Locator::max());
5532        }
5533
5534        let mut sorted_ids = sorted_ids.into_iter().peekable();
5535        locators.extend(
5536            sorted_ids
5537                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
5538                .map(|_| Locator::min()),
5539        );
5540
5541        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
5542        for id in sorted_ids {
5543            if cursor.seek_forward(&id, Bias::Left) {
5544                locators.push(cursor.item().unwrap().locator.clone());
5545            } else {
5546                panic!("invalid excerpt id {:?}", id);
5547            }
5548        }
5549
5550        locators.sort_unstable();
5551        locators
5552    }
5553
5554    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5555        Some(self.excerpt(excerpt_id)?.buffer_id)
5556    }
5557
5558    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5559        Some(&self.excerpt(excerpt_id)?.buffer)
5560    }
5561
5562    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
5563        let mut cursor = self
5564            .excerpts
5565            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
5566        let locator = self.excerpt_locator_for_id(excerpt_id);
5567        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
5568        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5569            sought_exact = true;
5570            cursor.prev();
5571        } else if excerpt_id == ExcerptId::min() {
5572            sought_exact = true;
5573        }
5574        if sought_exact {
5575            let start = cursor.start().1.clone();
5576            let end = cursor.end().1;
5577            let mut diff_transforms = self
5578                .diff_transforms
5579                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
5580            diff_transforms.seek(&start, Bias::Left);
5581            let overshoot = start.0 - diff_transforms.start().0.0;
5582            let start = diff_transforms.start().1.0 + overshoot;
5583            diff_transforms.seek(&end, Bias::Right);
5584            let overshoot = end.0 - diff_transforms.start().0.0;
5585            let end = diff_transforms.start().1.0 + overshoot;
5586            Some(start..end)
5587        } else {
5588            None
5589        }
5590    }
5591
5592    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5593        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5594        let locator = self.excerpt_locator_for_id(excerpt_id);
5595        cursor.seek(&Some(locator), Bias::Left);
5596        if let Some(excerpt) = cursor.item()
5597            && excerpt.id == excerpt_id
5598        {
5599            return Some(excerpt);
5600        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5601            cursor.prev();
5602            return cursor.item();
5603        }
5604        None
5605    }
5606
5607    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5608    pub fn excerpt_containing<T: ToOffset>(
5609        &self,
5610        range: Range<T>,
5611    ) -> Option<MultiBufferExcerpt<'_>> {
5612        let range = range.start.to_offset(self)..range.end.to_offset(self);
5613        let mut cursor = self.cursor::<usize>();
5614        cursor.seek(&range.start);
5615
5616        let start_excerpt = cursor.excerpt()?;
5617        if range.end != range.start {
5618            cursor.seek_forward(&range.end);
5619            if cursor.excerpt()?.id != start_excerpt.id {
5620                return None;
5621            }
5622        }
5623
5624        cursor.seek_to_start_of_current_excerpt();
5625        let region = cursor.region()?;
5626        let offset = region.range.start;
5627        let buffer_offset = start_excerpt.buffer_start_offset();
5628        let excerpt_offset = cursor.excerpts.start().clone();
5629        Some(MultiBufferExcerpt {
5630            diff_transforms: cursor.diff_transforms,
5631            excerpt: start_excerpt,
5632            offset,
5633            buffer_offset,
5634            excerpt_offset,
5635        })
5636    }
5637
5638    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
5639        if let Some(id) = anchor.buffer_id {
5640            return Some(id);
5641        }
5642        let excerpt = self.excerpt_containing(anchor..anchor)?;
5643        Some(excerpt.buffer_id())
5644    }
5645
5646    pub fn selections_in_range<'a>(
5647        &'a self,
5648        range: &'a Range<Anchor>,
5649        include_local: bool,
5650    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5651        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5652        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5653        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5654        cursor.seek(start_locator, Bias::Left);
5655        cursor
5656            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5657            .flat_map(move |excerpt| {
5658                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5659                if excerpt.id == range.start.excerpt_id {
5660                    query_range.start = range.start.text_anchor;
5661                }
5662                if excerpt.id == range.end.excerpt_id {
5663                    query_range.end = range.end.text_anchor;
5664                }
5665
5666                excerpt
5667                    .buffer
5668                    .selections_in_range(query_range, include_local)
5669                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5670                        selections.map(move |selection| {
5671                            let mut start =
5672                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.start);
5673                            let mut end =
5674                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.end);
5675                            if range.start.cmp(&start, self).is_gt() {
5676                                start = range.start;
5677                            }
5678                            if range.end.cmp(&end, self).is_lt() {
5679                                end = range.end;
5680                            }
5681
5682                            (
5683                                replica_id,
5684                                line_mode,
5685                                cursor_shape,
5686                                Selection {
5687                                    id: selection.id,
5688                                    start,
5689                                    end,
5690                                    reversed: selection.reversed,
5691                                    goal: selection.goal,
5692                                },
5693                            )
5694                        })
5695                    })
5696            })
5697    }
5698
5699    pub fn show_headers(&self) -> bool {
5700        self.show_headers
5701    }
5702
5703    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5704        self.diffs.get(&buffer_id)
5705    }
5706
5707    /// Visually annotates a position or range with the `Debug` representation of a value. The
5708    /// callsite of this function is used as a key - previous annotations will be removed.
5709    #[cfg(debug_assertions)]
5710    #[track_caller]
5711    pub fn debug<V, R>(&self, ranges: &R, value: V)
5712    where
5713        R: debug::ToMultiBufferDebugRanges,
5714        V: std::fmt::Debug,
5715    {
5716        self.debug_with_key(std::panic::Location::caller(), ranges, value);
5717    }
5718
5719    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
5720    /// debug annotations with the same key will be removed. The key is also used to determine the
5721    /// annotation's color.
5722    #[cfg(debug_assertions)]
5723    #[track_caller]
5724    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
5725    where
5726        K: std::hash::Hash + 'static,
5727        R: debug::ToMultiBufferDebugRanges,
5728        V: std::fmt::Debug,
5729    {
5730        let text_ranges = ranges
5731            .to_multi_buffer_debug_ranges(self)
5732            .into_iter()
5733            .flat_map(|range| {
5734                self.range_to_buffer_ranges(range).into_iter().map(
5735                    |(buffer, range, _excerpt_id)| {
5736                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
5737                    },
5738                )
5739            })
5740            .collect();
5741        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
5742            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
5743        });
5744    }
5745}
5746
5747#[cfg(any(test, feature = "test-support"))]
5748impl MultiBufferSnapshot {
5749    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5750        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
5751        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
5752        start..end
5753    }
5754
5755    #[cfg(any(test, feature = "test-support"))]
5756    fn check_invariants(&self) {
5757        let excerpts = self.excerpts.items(());
5758        let excerpt_ids = self.excerpt_ids.items(());
5759
5760        for (ix, excerpt) in excerpts.iter().enumerate() {
5761            if ix == 0 {
5762                if excerpt.locator <= Locator::min() {
5763                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5764                }
5765            } else if excerpt.locator <= excerpts[ix - 1].locator {
5766                panic!("excerpts are out-of-order: {:?}", excerpts);
5767            }
5768        }
5769
5770        for (ix, entry) in excerpt_ids.iter().enumerate() {
5771            if ix == 0 {
5772                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
5773                    panic!("invalid first excerpt id {:?}", entry.id);
5774                }
5775            } else if entry.id <= excerpt_ids[ix - 1].id {
5776                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5777            }
5778        }
5779
5780        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5781            panic!(
5782                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5783                self.excerpts.summary().text.len,
5784                self.diff_transforms.summary().input,
5785                self.diff_transforms.items(()),
5786            );
5787        }
5788
5789        let mut prev_transform: Option<&DiffTransform> = None;
5790        for item in self.diff_transforms.iter() {
5791            if let DiffTransform::BufferContent {
5792                summary,
5793                inserted_hunk_info,
5794            } = item
5795            {
5796                if let Some(DiffTransform::BufferContent {
5797                    inserted_hunk_info: prev_inserted_hunk_info,
5798                    ..
5799                }) = prev_transform
5800                    && *inserted_hunk_info == *prev_inserted_hunk_info
5801                {
5802                    panic!(
5803                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
5804                        self.diff_transforms.items(())
5805                    );
5806                }
5807                if summary.len == 0 && !self.is_empty() {
5808                    panic!("empty buffer content transform");
5809                }
5810            }
5811            prev_transform = Some(item);
5812        }
5813    }
5814}
5815
5816impl<'a, D> MultiBufferCursor<'a, D>
5817where
5818    D: TextDimension + Ord + Sub<D, Output = D>,
5819{
5820    fn seek(&mut self, position: &D) {
5821        self.cached_region.take();
5822        self.diff_transforms
5823            .seek(&OutputDimension(*position), Bias::Right);
5824        if self.diff_transforms.item().is_none()
5825            && *position == self.diff_transforms.start().output_dimension.0
5826        {
5827            self.diff_transforms.prev();
5828        }
5829
5830        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5831        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5832            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5833            excerpt_position.add_assign(&overshoot);
5834        }
5835
5836        self.excerpts
5837            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
5838        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5839            self.excerpts.prev();
5840        }
5841    }
5842
5843    fn seek_forward(&mut self, position: &D) {
5844        self.cached_region.take();
5845        self.diff_transforms
5846            .seek_forward(&OutputDimension(*position), Bias::Right);
5847        if self.diff_transforms.item().is_none()
5848            && *position == self.diff_transforms.start().output_dimension.0
5849        {
5850            self.diff_transforms.prev();
5851        }
5852
5853        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
5854        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
5855        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
5856            excerpt_position.add_assign(&overshoot);
5857        }
5858
5859        self.excerpts
5860            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
5861        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
5862            self.excerpts.prev();
5863        }
5864    }
5865
5866    fn next_excerpt(&mut self) {
5867        self.excerpts.next();
5868        self.seek_to_start_of_current_excerpt();
5869    }
5870
5871    fn prev_excerpt(&mut self) {
5872        self.excerpts.prev();
5873        self.seek_to_start_of_current_excerpt();
5874    }
5875
5876    fn seek_to_start_of_current_excerpt(&mut self) {
5877        self.cached_region.take();
5878        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
5879        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
5880            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
5881            && self.diff_transforms.next_item().is_some()
5882        {
5883            self.diff_transforms.next();
5884        }
5885    }
5886
5887    fn next(&mut self) {
5888        self.cached_region.take();
5889        match self
5890            .diff_transforms
5891            .end()
5892            .excerpt_dimension
5893            .cmp(&self.excerpts.end())
5894        {
5895            cmp::Ordering::Less => self.diff_transforms.next(),
5896            cmp::Ordering::Greater => self.excerpts.next(),
5897            cmp::Ordering::Equal => {
5898                self.diff_transforms.next();
5899                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
5900                    || self.diff_transforms.item().is_none()
5901                {
5902                    self.excerpts.next();
5903                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
5904                    self.diff_transforms.item()
5905                    && self
5906                        .excerpts
5907                        .item()
5908                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
5909                {
5910                    self.excerpts.next();
5911                }
5912            }
5913        }
5914    }
5915
5916    fn prev(&mut self) {
5917        self.cached_region.take();
5918        match self
5919            .diff_transforms
5920            .start()
5921            .excerpt_dimension
5922            .cmp(self.excerpts.start())
5923        {
5924            cmp::Ordering::Less => self.excerpts.prev(),
5925            cmp::Ordering::Greater => self.diff_transforms.prev(),
5926            cmp::Ordering::Equal => {
5927                self.diff_transforms.prev();
5928                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
5929                    || self.diff_transforms.item().is_none()
5930                {
5931                    self.excerpts.prev();
5932                }
5933            }
5934        }
5935    }
5936
5937    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
5938        if self.cached_region.is_none() {
5939            self.cached_region = self.build_region();
5940        }
5941        self.cached_region.clone()
5942    }
5943
5944    fn is_at_start_of_excerpt(&mut self) -> bool {
5945        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
5946            return false;
5947        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
5948            return true;
5949        }
5950
5951        self.diff_transforms.prev();
5952        let prev_transform = self.diff_transforms.item();
5953        self.diff_transforms.next();
5954
5955        prev_transform.is_none_or(|next_transform| {
5956            matches!(next_transform, DiffTransform::BufferContent { .. })
5957        })
5958    }
5959
5960    fn is_at_end_of_excerpt(&mut self) -> bool {
5961        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
5962            return false;
5963        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
5964            || self.diff_transforms.item().is_none()
5965        {
5966            return true;
5967        }
5968
5969        let next_transform = self.diff_transforms.next_item();
5970        next_transform.is_none_or(|next_transform| match next_transform {
5971            DiffTransform::BufferContent { .. } => true,
5972            DiffTransform::DeletedHunk { hunk_info, .. } => self
5973                .excerpts
5974                .item()
5975                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
5976        })
5977    }
5978
5979    fn main_buffer_position(&self) -> Option<D> {
5980        let excerpt = self.excerpts.item()?;
5981        let buffer = &excerpt.buffer;
5982        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
5983        let mut buffer_start = buffer_context_start;
5984        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
5985        buffer_start.add_assign(&overshoot);
5986        Some(buffer_start)
5987    }
5988
5989    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
5990        let excerpt = self.excerpts.item()?;
5991        match self.diff_transforms.item()? {
5992            DiffTransform::DeletedHunk {
5993                buffer_id,
5994                base_text_byte_range,
5995                has_trailing_newline,
5996                hunk_info,
5997                ..
5998            } => {
5999                let diff = self.diffs.get(buffer_id)?;
6000                let buffer = diff.base_text();
6001                let mut rope_cursor = buffer.as_rope().cursor(0);
6002                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6003                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6004                let mut buffer_end = buffer_start;
6005                buffer_end.add_assign(&buffer_range_len);
6006                let start = self.diff_transforms.start().output_dimension.0;
6007                let end = self.diff_transforms.end().output_dimension.0;
6008                Some(MultiBufferRegion {
6009                    buffer,
6010                    excerpt,
6011                    has_trailing_newline: *has_trailing_newline,
6012                    is_main_buffer: false,
6013                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6014                        hunk_info.hunk_secondary_status,
6015                    )),
6016                    buffer_range: buffer_start..buffer_end,
6017                    range: start..end,
6018                })
6019            }
6020            DiffTransform::BufferContent {
6021                inserted_hunk_info, ..
6022            } => {
6023                let buffer = &excerpt.buffer;
6024                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6025
6026                let mut start = self.diff_transforms.start().output_dimension.0;
6027                let mut buffer_start = buffer_context_start;
6028                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6029                    let overshoot =
6030                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6031                    start.add_assign(&overshoot);
6032                } else {
6033                    let overshoot =
6034                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6035                    buffer_start.add_assign(&overshoot);
6036                }
6037
6038                let mut end;
6039                let mut buffer_end;
6040                let has_trailing_newline;
6041                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6042                    let overshoot =
6043                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6044                    end = self.diff_transforms.end().output_dimension.0;
6045                    buffer_end = buffer_context_start;
6046                    buffer_end.add_assign(&overshoot);
6047                    has_trailing_newline = false;
6048                } else {
6049                    let overshoot =
6050                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6051                    end = self.diff_transforms.start().output_dimension.0;
6052                    end.add_assign(&overshoot);
6053                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6054                    has_trailing_newline = excerpt.has_trailing_newline;
6055                };
6056
6057                Some(MultiBufferRegion {
6058                    buffer,
6059                    excerpt,
6060                    has_trailing_newline,
6061                    is_main_buffer: true,
6062                    diff_hunk_status: inserted_hunk_info
6063                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6064                    buffer_range: buffer_start..buffer_end,
6065                    range: start..end,
6066                })
6067            }
6068        }
6069    }
6070
6071    fn excerpt(&self) -> Option<&'a Excerpt> {
6072        self.excerpts.item()
6073    }
6074}
6075
6076impl Excerpt {
6077    fn new(
6078        id: ExcerptId,
6079        locator: Locator,
6080        buffer_id: BufferId,
6081        buffer: BufferSnapshot,
6082        range: ExcerptRange<text::Anchor>,
6083        has_trailing_newline: bool,
6084    ) -> Self {
6085        Excerpt {
6086            id,
6087            locator,
6088            max_buffer_row: range.context.end.to_point(&buffer).row,
6089            text_summary: buffer
6090                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6091            buffer_id,
6092            buffer,
6093            range,
6094            has_trailing_newline,
6095        }
6096    }
6097
6098    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6099        let content_start = self.range.context.start.to_offset(&self.buffer);
6100        let chunks_start = content_start + range.start;
6101        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6102
6103        let has_footer = self.has_trailing_newline
6104            && range.start <= self.text_summary.len
6105            && range.end > self.text_summary.len;
6106
6107        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6108
6109        ExcerptChunks {
6110            excerpt_id: self.id,
6111            content_chunks,
6112            has_footer,
6113        }
6114    }
6115
6116    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6117        let content_start = self.range.context.start.to_offset(&self.buffer);
6118        let chunks_start = content_start + range.start;
6119        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6120        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6121        excerpt_chunks.has_footer = self.has_trailing_newline
6122            && range.start <= self.text_summary.len
6123            && range.end > self.text_summary.len;
6124    }
6125
6126    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6127        if text_anchor
6128            .cmp(&self.range.context.start, &self.buffer)
6129            .is_lt()
6130        {
6131            self.range.context.start
6132        } else if text_anchor
6133            .cmp(&self.range.context.end, &self.buffer)
6134            .is_gt()
6135        {
6136            self.range.context.end
6137        } else {
6138            text_anchor
6139        }
6140    }
6141
6142    fn contains(&self, anchor: &Anchor) -> bool {
6143        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
6144            && self
6145                .range
6146                .context
6147                .start
6148                .cmp(&anchor.text_anchor, &self.buffer)
6149                .is_le()
6150            && self
6151                .range
6152                .context
6153                .end
6154                .cmp(&anchor.text_anchor, &self.buffer)
6155                .is_ge()
6156    }
6157
6158    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6159    fn buffer_start_offset(&self) -> usize {
6160        self.range.context.start.to_offset(&self.buffer)
6161    }
6162
6163    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6164    fn buffer_end_offset(&self) -> usize {
6165        self.buffer_start_offset() + self.text_summary.len
6166    }
6167}
6168
6169impl<'a> MultiBufferExcerpt<'a> {
6170    pub fn id(&self) -> ExcerptId {
6171        self.excerpt.id
6172    }
6173
6174    pub fn buffer_id(&self) -> BufferId {
6175        self.excerpt.buffer_id
6176    }
6177
6178    pub fn start_anchor(&self) -> Anchor {
6179        Anchor::in_buffer(
6180            self.excerpt.id,
6181            self.excerpt.buffer_id,
6182            self.excerpt.range.context.start,
6183        )
6184    }
6185
6186    pub fn end_anchor(&self) -> Anchor {
6187        Anchor::in_buffer(
6188            self.excerpt.id,
6189            self.excerpt.buffer_id,
6190            self.excerpt.range.context.end,
6191        )
6192    }
6193
6194    pub fn buffer(&self) -> &'a BufferSnapshot {
6195        &self.excerpt.buffer
6196    }
6197
6198    pub fn buffer_range(&self) -> Range<usize> {
6199        self.buffer_offset
6200            ..self
6201                .excerpt
6202                .range
6203                .context
6204                .end
6205                .to_offset(&self.excerpt.buffer.text)
6206    }
6207
6208    pub fn start_offset(&self) -> usize {
6209        self.offset
6210    }
6211
6212    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6213    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6214        self.map_range_to_buffer(offset..offset).start
6215    }
6216
6217    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6218    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6219        self.diff_transforms
6220            .seek(&OutputDimension(range.start), Bias::Right);
6221        let start = self.map_offset_to_buffer_internal(range.start);
6222        let end = if range.end > range.start {
6223            self.diff_transforms
6224                .seek_forward(&OutputDimension(range.end), Bias::Right);
6225            self.map_offset_to_buffer_internal(range.end)
6226        } else {
6227            start
6228        };
6229        start..end
6230    }
6231
6232    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6233        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
6234        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6235            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
6236        };
6237        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6238        self.buffer_offset + offset_in_excerpt
6239    }
6240
6241    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6242    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6243        self.map_range_from_buffer(buffer_offset..buffer_offset)
6244            .start
6245    }
6246
6247    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6248    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6249        if buffer_range.start < self.buffer_offset {
6250            log::warn!(
6251                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6252            );
6253            return buffer_range;
6254        }
6255        let overshoot = buffer_range.start - self.buffer_offset;
6256        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6257        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
6258        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
6259            log::warn!(
6260                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6261            );
6262            return buffer_range;
6263        }
6264        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6265        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
6266
6267        let end = if buffer_range.end > buffer_range.start {
6268            let overshoot = buffer_range.end - self.buffer_offset;
6269            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6270            self.diff_transforms
6271                .seek_forward(&excerpt_offset, Bias::Right);
6272            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6273            self.diff_transforms.start().output_dimension.0 + overshoot
6274        } else {
6275            start
6276        };
6277
6278        start..end
6279    }
6280
6281    /// Returns true if the entirety of the given range is in the buffer's excerpt
6282    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6283        range.start >= self.excerpt.buffer_start_offset()
6284            && range.end <= self.excerpt.buffer_end_offset()
6285    }
6286
6287    pub fn max_buffer_row(&self) -> u32 {
6288        self.excerpt.max_buffer_row
6289    }
6290}
6291
6292impl ExcerptId {
6293    pub fn min() -> Self {
6294        Self(0)
6295    }
6296
6297    pub fn max() -> Self {
6298        Self(u32::MAX)
6299    }
6300
6301    pub fn to_proto(self) -> u64 {
6302        self.0 as _
6303    }
6304
6305    pub fn from_proto(proto: u64) -> Self {
6306        Self(proto as _)
6307    }
6308
6309    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6310        let a = snapshot.excerpt_locator_for_id(*self);
6311        let b = snapshot.excerpt_locator_for_id(*other);
6312        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6313    }
6314}
6315
6316impl From<ExcerptId> for usize {
6317    fn from(val: ExcerptId) -> Self {
6318        val.0 as usize
6319    }
6320}
6321
6322impl fmt::Debug for Excerpt {
6323    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6324        f.debug_struct("Excerpt")
6325            .field("id", &self.id)
6326            .field("locator", &self.locator)
6327            .field("buffer_id", &self.buffer_id)
6328            .field("range", &self.range)
6329            .field("text_summary", &self.text_summary)
6330            .field("has_trailing_newline", &self.has_trailing_newline)
6331            .finish()
6332    }
6333}
6334
6335impl sum_tree::Item for Excerpt {
6336    type Summary = ExcerptSummary;
6337
6338    fn summary(&self, _cx: ()) -> Self::Summary {
6339        let mut text = self.text_summary;
6340        if self.has_trailing_newline {
6341            text += TextSummary::from("\n");
6342        }
6343        ExcerptSummary {
6344            excerpt_id: self.id,
6345            excerpt_locator: self.locator.clone(),
6346            widest_line_number: self.max_buffer_row,
6347            text,
6348        }
6349    }
6350}
6351
6352impl sum_tree::Item for ExcerptIdMapping {
6353    type Summary = ExcerptId;
6354
6355    fn summary(&self, _cx: ()) -> Self::Summary {
6356        self.id
6357    }
6358}
6359
6360impl sum_tree::KeyedItem for ExcerptIdMapping {
6361    type Key = ExcerptId;
6362
6363    fn key(&self) -> Self::Key {
6364        self.id
6365    }
6366}
6367
6368impl DiffTransform {
6369    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6370        match self {
6371            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6372            DiffTransform::BufferContent {
6373                inserted_hunk_info, ..
6374            } => *inserted_hunk_info,
6375        }
6376    }
6377}
6378
6379impl sum_tree::Item for DiffTransform {
6380    type Summary = DiffTransformSummary;
6381
6382    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
6383        match self {
6384            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6385                input: *summary,
6386                output: *summary,
6387            },
6388            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6389                input: TextSummary::default(),
6390                output: *summary,
6391            },
6392        }
6393    }
6394}
6395
6396impl DiffTransformSummary {
6397    fn excerpt_len(&self) -> ExcerptOffset {
6398        ExcerptOffset::new(self.input.len)
6399    }
6400}
6401
6402impl sum_tree::ContextLessSummary for DiffTransformSummary {
6403    fn zero() -> Self {
6404        DiffTransformSummary {
6405            input: TextSummary::default(),
6406            output: TextSummary::default(),
6407        }
6408    }
6409
6410    fn add_summary(&mut self, other: &Self) {
6411        self.input += other.input;
6412        self.output += other.output;
6413    }
6414}
6415
6416impl sum_tree::ContextLessSummary for ExcerptId {
6417    fn zero() -> Self {
6418        Self(0)
6419    }
6420
6421    fn add_summary(&mut self, summary: &Self) {
6422        *self = cmp::max(*self, *summary);
6423    }
6424}
6425
6426impl sum_tree::ContextLessSummary for ExcerptSummary {
6427    fn zero() -> Self {
6428        Self::default()
6429    }
6430
6431    fn add_summary(&mut self, summary: &Self) {
6432        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6433        self.excerpt_locator = summary.excerpt_locator.clone();
6434        Summary::add_summary(&mut self.text, &summary.text, ());
6435        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6436    }
6437}
6438
6439impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6440    fn zero(_cx: ()) -> Self {
6441        Default::default()
6442    }
6443
6444    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6445        self.value += summary.text.len;
6446    }
6447}
6448
6449impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6450    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6451        Ord::cmp(&self.value, &cursor_location.text.len)
6452    }
6453}
6454
6455impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6456    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
6457        Ord::cmp(&Some(self), cursor_location)
6458    }
6459}
6460
6461impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6462    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6463        Ord::cmp(self, &cursor_location.excerpt_locator)
6464    }
6465}
6466
6467impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6468    fn zero(_cx: ()) -> Self {
6469        Default::default()
6470    }
6471
6472    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6473        self.value += summary.text.lines;
6474    }
6475}
6476
6477impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
6478    for ExcerptDimension<D>
6479{
6480    fn zero(_: ()) -> Self {
6481        ExcerptDimension(D::default())
6482    }
6483
6484    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6485        self.0.add_assign(&D::from_text_summary(&summary.text))
6486    }
6487}
6488
6489impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6490    fn zero(_cx: ()) -> Self {
6491        Default::default()
6492    }
6493
6494    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6495        *self = Some(&summary.excerpt_locator);
6496    }
6497}
6498
6499impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6500    fn zero(_cx: ()) -> Self {
6501        Default::default()
6502    }
6503
6504    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6505        *self = Some(summary.excerpt_id);
6506    }
6507}
6508
6509#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6510struct ExcerptDimension<T>(T);
6511
6512#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6513struct OutputDimension<T>(T);
6514
6515impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6516    fn zero(_: ()) -> Self {
6517        ExcerptOffset::new(0)
6518    }
6519
6520    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6521        self.value += summary.input.len;
6522    }
6523}
6524
6525impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6526    fn zero(_: ()) -> Self {
6527        ExcerptPoint::new(0, 0)
6528    }
6529
6530    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6531        self.value += summary.input.lines;
6532    }
6533}
6534
6535impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6536    for ExcerptDimension<D>
6537{
6538    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
6539        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
6540    }
6541}
6542
6543impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6544    for ExcerptDimension<D>
6545{
6546    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6547        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
6548    }
6549}
6550
6551impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
6552    fn zero(_: ()) -> Self {
6553        ExcerptDimension(D::default())
6554    }
6555
6556    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6557        self.0.add_assign(&D::from_text_summary(&summary.input))
6558    }
6559}
6560
6561impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
6562    for OutputDimension<D>
6563{
6564    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: ()) -> cmp::Ordering {
6565        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
6566    }
6567}
6568
6569impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
6570    fn zero(_: ()) -> Self {
6571        OutputDimension(D::default())
6572    }
6573
6574    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6575        self.0.add_assign(&D::from_text_summary(&summary.output))
6576    }
6577}
6578
6579impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6580    fn zero(_: ()) -> Self {
6581        TextSummary::default()
6582    }
6583
6584    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6585        *self += summary.output
6586    }
6587}
6588
6589impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6590    fn zero(_: ()) -> Self {
6591        0
6592    }
6593
6594    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6595        *self += summary.output.len
6596    }
6597}
6598
6599impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
6600    fn zero(_: ()) -> Self {
6601        Point::new(0, 0)
6602    }
6603
6604    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6605        *self += summary.output.lines
6606    }
6607}
6608
6609impl MultiBufferRows<'_> {
6610    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
6611        self.point = Point::new(row, 0);
6612        self.cursor.seek(&self.point);
6613    }
6614}
6615
6616impl Iterator for MultiBufferRows<'_> {
6617    type Item = RowInfo;
6618
6619    fn next(&mut self) -> Option<Self::Item> {
6620        if self.is_empty && self.point.row == 0 {
6621            self.point += Point::new(1, 0);
6622            return Some(RowInfo {
6623                buffer_id: None,
6624                buffer_row: Some(0),
6625                multibuffer_row: Some(MultiBufferRow(0)),
6626                diff_status: None,
6627                expand_info: None,
6628            });
6629        }
6630
6631        let mut region = self.cursor.region()?;
6632        while self.point >= region.range.end {
6633            self.cursor.next();
6634            if let Some(next_region) = self.cursor.region() {
6635                region = next_region;
6636            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
6637                let multibuffer_row = MultiBufferRow(self.point.row);
6638                let last_excerpt = self
6639                    .cursor
6640                    .excerpts
6641                    .item()
6642                    .or(self.cursor.excerpts.prev_item())?;
6643                let last_row = last_excerpt
6644                    .range
6645                    .context
6646                    .end
6647                    .to_point(&last_excerpt.buffer)
6648                    .row;
6649
6650                let first_row = last_excerpt
6651                    .range
6652                    .context
6653                    .start
6654                    .to_point(&last_excerpt.buffer)
6655                    .row;
6656
6657                let expand_info = if self.is_singleton {
6658                    None
6659                } else {
6660                    let needs_expand_up = first_row == last_row
6661                        && last_row > 0
6662                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
6663                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
6664
6665                    if needs_expand_up && needs_expand_down {
6666                        Some(ExpandExcerptDirection::UpAndDown)
6667                    } else if needs_expand_up {
6668                        Some(ExpandExcerptDirection::Up)
6669                    } else if needs_expand_down {
6670                        Some(ExpandExcerptDirection::Down)
6671                    } else {
6672                        None
6673                    }
6674                    .map(|direction| ExpandInfo {
6675                        direction,
6676                        excerpt_id: last_excerpt.id,
6677                    })
6678                };
6679                self.point += Point::new(1, 0);
6680                return Some(RowInfo {
6681                    buffer_id: Some(last_excerpt.buffer_id),
6682                    buffer_row: Some(last_row),
6683                    multibuffer_row: Some(multibuffer_row),
6684                    diff_status: None,
6685                    expand_info,
6686                });
6687            } else {
6688                return None;
6689            };
6690        }
6691
6692        let overshoot = self.point - region.range.start;
6693        let buffer_point = region.buffer_range.start + overshoot;
6694        let expand_info = if self.is_singleton {
6695            None
6696        } else {
6697            let needs_expand_up = self.point.row == region.range.start.row
6698                && self.cursor.is_at_start_of_excerpt()
6699                && buffer_point.row > 0;
6700            let needs_expand_down = (region.excerpt.has_trailing_newline
6701                && self.point.row + 1 == region.range.end.row
6702                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
6703                && self.cursor.is_at_end_of_excerpt()
6704                && buffer_point.row < region.buffer.max_point().row;
6705
6706            if needs_expand_up && needs_expand_down {
6707                Some(ExpandExcerptDirection::UpAndDown)
6708            } else if needs_expand_up {
6709                Some(ExpandExcerptDirection::Up)
6710            } else if needs_expand_down {
6711                Some(ExpandExcerptDirection::Down)
6712            } else {
6713                None
6714            }
6715            .map(|direction| ExpandInfo {
6716                direction,
6717                excerpt_id: region.excerpt.id,
6718            })
6719        };
6720
6721        let result = Some(RowInfo {
6722            buffer_id: Some(region.buffer.remote_id()),
6723            buffer_row: Some(buffer_point.row),
6724            multibuffer_row: Some(MultiBufferRow(self.point.row)),
6725            diff_status: region
6726                .diff_hunk_status
6727                .filter(|_| self.point < region.range.end),
6728            expand_info,
6729        });
6730        self.point += Point::new(1, 0);
6731        result
6732    }
6733}
6734
6735impl<'a> MultiBufferChunks<'a> {
6736    pub fn offset(&self) -> usize {
6737        self.range.start
6738    }
6739
6740    pub fn seek(&mut self, range: Range<usize>) {
6741        self.diff_transforms.seek(&range.end, Bias::Right);
6742        let mut excerpt_end = self.diff_transforms.start().1;
6743        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6744            let overshoot = range.end - self.diff_transforms.start().0;
6745            excerpt_end.value += overshoot;
6746        }
6747
6748        self.diff_transforms.seek(&range.start, Bias::Right);
6749        let mut excerpt_start = self.diff_transforms.start().1;
6750        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6751            let overshoot = range.start - self.diff_transforms.start().0;
6752            excerpt_start.value += overshoot;
6753        }
6754
6755        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
6756        self.buffer_chunk.take();
6757        self.range = range;
6758    }
6759
6760    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
6761        self.excerpt_offset_range = new_range.clone();
6762        self.excerpts.seek(&new_range.start, Bias::Right);
6763        if let Some(excerpt) = self.excerpts.item() {
6764            let excerpt_start = *self.excerpts.start();
6765            if let Some(excerpt_chunks) = self
6766                .excerpt_chunks
6767                .as_mut()
6768                .filter(|chunks| excerpt.id == chunks.excerpt_id)
6769            {
6770                excerpt.seek_chunks(
6771                    excerpt_chunks,
6772                    (self.excerpt_offset_range.start - excerpt_start).value
6773                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6774                );
6775            } else {
6776                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6777                    (self.excerpt_offset_range.start - excerpt_start).value
6778                        ..(self.excerpt_offset_range.end - excerpt_start).value,
6779                    self.language_aware,
6780                ));
6781            }
6782        } else {
6783            self.excerpt_chunks = None;
6784        }
6785    }
6786
6787    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
6788        loop {
6789            if self.excerpt_offset_range.is_empty() {
6790                return None;
6791            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
6792                self.excerpt_offset_range.start.value += chunk.text.len();
6793                return Some(chunk);
6794            } else {
6795                self.excerpts.next();
6796                let excerpt = self.excerpts.item()?;
6797                self.excerpt_chunks = Some(excerpt.chunks_in_range(
6798                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
6799                    self.language_aware,
6800                ));
6801            }
6802        }
6803    }
6804}
6805
6806impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
6807    type Item = &'a str;
6808
6809    fn next(&mut self) -> Option<Self::Item> {
6810        let mut region = self.cursor.region()?;
6811        if self.offset == region.range.start {
6812            self.cursor.prev();
6813            region = self.cursor.region()?;
6814            let start_overshoot = self.start.saturating_sub(region.range.start);
6815            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
6816                region.buffer_range.start + start_overshoot..region.buffer_range.end,
6817            ));
6818        }
6819
6820        if self.offset == region.range.end && region.has_trailing_newline {
6821            self.offset -= 1;
6822            Some("\n")
6823        } else {
6824            let chunk = self.current_chunks.as_mut().unwrap().next()?;
6825            self.offset -= chunk.len();
6826            Some(chunk)
6827        }
6828    }
6829}
6830
6831impl<'a> Iterator for MultiBufferChunks<'a> {
6832    type Item = Chunk<'a>;
6833
6834    fn next(&mut self) -> Option<Chunk<'a>> {
6835        if self.range.start >= self.range.end {
6836            return None;
6837        }
6838        if self.range.start == self.diff_transforms.end().0 {
6839            self.diff_transforms.next();
6840        }
6841
6842        let diff_transform_start = self.diff_transforms.start().0;
6843        let diff_transform_end = self.diff_transforms.end().0;
6844        debug_assert!(self.range.start < diff_transform_end);
6845
6846        let diff_transform = self.diff_transforms.item()?;
6847        match diff_transform {
6848            DiffTransform::BufferContent { .. } => {
6849                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
6850                    chunk
6851                } else {
6852                    let chunk = self.next_excerpt_chunk().unwrap();
6853                    self.buffer_chunk.insert(chunk)
6854                };
6855
6856                let chunk_end = self.range.start + chunk.text.len();
6857                let diff_transform_end = diff_transform_end.min(self.range.end);
6858
6859                if diff_transform_end < chunk_end {
6860                    let split_idx = diff_transform_end - self.range.start;
6861                    let (before, after) = chunk.text.split_at(split_idx);
6862                    self.range.start = diff_transform_end;
6863                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
6864                    let chars = chunk.chars & mask;
6865                    let tabs = chunk.tabs & mask;
6866
6867                    chunk.text = after;
6868                    chunk.chars = chunk.chars >> split_idx;
6869                    chunk.tabs = chunk.tabs >> split_idx;
6870
6871                    Some(Chunk {
6872                        text: before,
6873                        chars,
6874                        tabs,
6875                        ..chunk.clone()
6876                    })
6877                } else {
6878                    self.range.start = chunk_end;
6879                    self.buffer_chunk.take()
6880                }
6881            }
6882            DiffTransform::DeletedHunk {
6883                buffer_id,
6884                base_text_byte_range,
6885                has_trailing_newline,
6886                ..
6887            } => {
6888                let base_text_start =
6889                    base_text_byte_range.start + self.range.start - diff_transform_start;
6890                let base_text_end =
6891                    base_text_byte_range.start + self.range.end - diff_transform_start;
6892                let base_text_end = base_text_end.min(base_text_byte_range.end);
6893
6894                let mut chunks = if let Some((_, mut chunks)) = self
6895                    .diff_base_chunks
6896                    .take()
6897                    .filter(|(id, _)| id == buffer_id)
6898                {
6899                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
6900                    {
6901                        chunks.seek(base_text_start..base_text_end);
6902                    }
6903                    chunks
6904                } else {
6905                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
6906                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
6907                };
6908
6909                let chunk = if let Some(chunk) = chunks.next() {
6910                    self.range.start += chunk.text.len();
6911                    self.diff_base_chunks = Some((*buffer_id, chunks));
6912                    chunk
6913                } else {
6914                    debug_assert!(has_trailing_newline);
6915                    self.range.start += "\n".len();
6916                    Chunk {
6917                        text: "\n",
6918                        chars: 1u128,
6919                        ..Default::default()
6920                    }
6921                };
6922                Some(chunk)
6923            }
6924        }
6925    }
6926}
6927
6928impl MultiBufferBytes<'_> {
6929    fn consume(&mut self, len: usize) {
6930        self.range.start += len;
6931        self.chunk = &self.chunk[len..];
6932
6933        if !self.range.is_empty() && self.chunk.is_empty() {
6934            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
6935                self.chunk = chunk;
6936            } else if self.has_trailing_newline {
6937                self.has_trailing_newline = false;
6938                self.chunk = b"\n";
6939            } else {
6940                self.cursor.next();
6941                if let Some(region) = self.cursor.region() {
6942                    let mut excerpt_bytes = region.buffer.bytes_in_range(
6943                        region.buffer_range.start
6944                            ..(region.buffer_range.start + self.range.end - region.range.start)
6945                                .min(region.buffer_range.end),
6946                    );
6947                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
6948                    self.excerpt_bytes = Some(excerpt_bytes);
6949                    self.has_trailing_newline =
6950                        region.has_trailing_newline && self.range.end >= region.range.end;
6951                    if self.chunk.is_empty() && self.has_trailing_newline {
6952                        self.has_trailing_newline = false;
6953                        self.chunk = b"\n";
6954                    }
6955                }
6956            }
6957        }
6958    }
6959}
6960
6961impl<'a> Iterator for MultiBufferBytes<'a> {
6962    type Item = &'a [u8];
6963
6964    fn next(&mut self) -> Option<Self::Item> {
6965        let chunk = self.chunk;
6966        if chunk.is_empty() {
6967            None
6968        } else {
6969            self.consume(chunk.len());
6970            Some(chunk)
6971        }
6972    }
6973}
6974
6975impl io::Read for MultiBufferBytes<'_> {
6976    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
6977        let len = cmp::min(buf.len(), self.chunk.len());
6978        buf[..len].copy_from_slice(&self.chunk[..len]);
6979        if len > 0 {
6980            self.consume(len);
6981        }
6982        Ok(len)
6983    }
6984}
6985
6986impl io::Read for ReversedMultiBufferBytes<'_> {
6987    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
6988        let len = cmp::min(buf.len(), self.chunk.len());
6989        buf[..len].copy_from_slice(&self.chunk[..len]);
6990        buf[..len].reverse();
6991        if len > 0 {
6992            self.range.end -= len;
6993            self.chunk = &self.chunk[..self.chunk.len() - len];
6994            if !self.range.is_empty()
6995                && self.chunk.is_empty()
6996                && let Some(chunk) = self.chunks.next()
6997            {
6998                self.chunk = chunk.as_bytes();
6999            }
7000        }
7001        Ok(len)
7002    }
7003}
7004
7005impl<'a> Iterator for ExcerptChunks<'a> {
7006    type Item = Chunk<'a>;
7007
7008    fn next(&mut self) -> Option<Self::Item> {
7009        if let Some(chunk) = self.content_chunks.next() {
7010            return Some(chunk);
7011        }
7012
7013        if self.has_footer {
7014            let text = "\n";
7015            let chars = 0b1;
7016            self.has_footer = false;
7017            return Some(Chunk {
7018                text,
7019                chars,
7020                ..Default::default()
7021            });
7022        }
7023
7024        None
7025    }
7026}
7027
7028impl ToOffset for Point {
7029    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7030        snapshot.point_to_offset(*self)
7031    }
7032    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7033        snapshot.point_to_offset_utf16(*self)
7034    }
7035}
7036
7037impl ToOffset for usize {
7038    #[track_caller]
7039    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7040        assert!(
7041            *self <= snapshot.len(),
7042            "offset {} is greater than the snapshot.len() {}",
7043            *self,
7044            snapshot.len(),
7045        );
7046        *self
7047    }
7048    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7049        snapshot.offset_to_offset_utf16(*self)
7050    }
7051}
7052
7053impl ToOffset for OffsetUtf16 {
7054    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7055        snapshot.offset_utf16_to_offset(*self)
7056    }
7057
7058    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7059        *self
7060    }
7061}
7062
7063impl ToOffset for PointUtf16 {
7064    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7065        snapshot.point_utf16_to_offset(*self)
7066    }
7067    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7068        snapshot.point_utf16_to_offset_utf16(*self)
7069    }
7070}
7071
7072impl ToPoint for usize {
7073    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7074        snapshot.offset_to_point(*self)
7075    }
7076    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7077        snapshot.offset_to_point_utf16(*self)
7078    }
7079}
7080
7081impl ToPoint for Point {
7082    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7083        *self
7084    }
7085    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7086        snapshot.point_to_point_utf16(*self)
7087    }
7088}
7089
7090impl ToPoint for PointUtf16 {
7091    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7092        snapshot.point_utf16_to_point(*self)
7093    }
7094    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7095        *self
7096    }
7097}
7098
7099impl From<ExcerptId> for EntityId {
7100    fn from(id: ExcerptId) -> Self {
7101        EntityId::from(id.0 as u64)
7102    }
7103}
7104
7105#[cfg(debug_assertions)]
7106pub mod debug {
7107    use super::*;
7108
7109    pub trait ToMultiBufferDebugRanges {
7110        fn to_multi_buffer_debug_ranges(&self, snapshot: &MultiBufferSnapshot)
7111        -> Vec<Range<usize>>;
7112    }
7113
7114    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
7115        fn to_multi_buffer_debug_ranges(
7116            &self,
7117            snapshot: &MultiBufferSnapshot,
7118        ) -> Vec<Range<usize>> {
7119            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
7120        }
7121    }
7122
7123    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
7124        fn to_multi_buffer_debug_ranges(
7125            &self,
7126            snapshot: &MultiBufferSnapshot,
7127        ) -> Vec<Range<usize>> {
7128            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
7129                .to_multi_buffer_debug_ranges(snapshot)
7130        }
7131    }
7132
7133    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
7134        fn to_multi_buffer_debug_ranges(
7135            &self,
7136            snapshot: &MultiBufferSnapshot,
7137        ) -> Vec<Range<usize>> {
7138            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7139        }
7140    }
7141
7142    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
7143        fn to_multi_buffer_debug_ranges(
7144            &self,
7145            snapshot: &MultiBufferSnapshot,
7146        ) -> Vec<Range<usize>> {
7147            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7148        }
7149    }
7150
7151    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
7152        fn to_multi_buffer_debug_ranges(
7153            &self,
7154            snapshot: &MultiBufferSnapshot,
7155        ) -> Vec<Range<usize>> {
7156            self.iter()
7157                .map(|item| {
7158                    let offset = item.to_offset(snapshot);
7159                    offset..offset
7160                })
7161                .collect()
7162        }
7163    }
7164
7165    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
7166        fn to_multi_buffer_debug_ranges(
7167            &self,
7168            snapshot: &MultiBufferSnapshot,
7169        ) -> Vec<Range<usize>> {
7170            self.iter()
7171                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
7172                .collect()
7173        }
7174    }
7175}
7176
7177#[cfg(feature = "test-support")]
7178pub fn randomly_mutate_multibuffer_with_diffs(
7179    multibuffer: Entity<MultiBuffer>,
7180    buffers: &mut Vec<Entity<Buffer>>,
7181    base_texts: &mut HashMap<BufferId, String>,
7182    needs_diff_calculation: &mut bool,
7183    mut rng: rand::rngs::StdRng,
7184    cx: &mut gpui::TestAppContext,
7185) {
7186    use rand::Rng as _;
7187    use rand::seq::IndexedRandom as _;
7188
7189    let excerpt_ids = multibuffer.read_with(cx, |multibuffer, _| multibuffer.excerpt_ids());
7190    match rng.random_range(0..100) {
7191        0..=14 if !buffers.is_empty() => {
7192            let buffer = buffers.choose(&mut rng).unwrap();
7193            buffer.update(cx, |buf, cx| {
7194                let edit_count = rng.random_range(1..5);
7195                log::info!("editing buffer");
7196                buf.randomly_edit(&mut rng, edit_count, cx);
7197                *needs_diff_calculation = true;
7198            });
7199        }
7200        15..=19 if !excerpt_ids.is_empty() => {
7201            multibuffer.update(cx, |multibuffer, cx| {
7202                let ids = multibuffer.excerpt_ids();
7203                let mut excerpts = HashSet::default();
7204                for _ in 0..rng.random_range(0..ids.len()) {
7205                    excerpts.extend(ids.choose(&mut rng).copied());
7206                }
7207
7208                let line_count = rng.random_range(0..5);
7209
7210                log::info!("Expanding excerpts by {line_count} lines");
7211                multibuffer.expand_excerpts(
7212                    excerpts.iter().cloned(),
7213                    line_count,
7214                    ExpandExcerptDirection::UpAndDown,
7215                    cx,
7216                );
7217            });
7218        }
7219        20..=29 if !excerpt_ids.is_empty() => {
7220            let mut ids_to_remove = vec![];
7221            for _ in 0..rng.random_range(1..=3) {
7222                let Some(id) = excerpt_ids.choose(&mut rng) else {
7223                    break;
7224                };
7225                ids_to_remove.push(*id);
7226            }
7227            let snapshot = multibuffer.read_with(cx, |multibuffer, cx| multibuffer.snapshot(cx));
7228            ids_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
7229            drop(snapshot);
7230            multibuffer.update(cx, |multibuffer, cx| {
7231                multibuffer.remove_excerpts(ids_to_remove, cx)
7232            });
7233        }
7234        56..=85 if *needs_diff_calculation => {
7235            multibuffer.update(cx, |multibuffer, cx| {
7236                for buffer in multibuffer.all_buffers() {
7237                    let snapshot = buffer.read(cx).snapshot();
7238                    multibuffer
7239                        .diff_for(snapshot.remote_id())
7240                        .unwrap()
7241                        .update(cx, |diff, cx| {
7242                            log::info!("recalculating diff for buffer {:?}", snapshot.remote_id(),);
7243                            diff.recalculate_diff_sync(snapshot.text, cx);
7244                        });
7245                }
7246                *needs_diff_calculation = false;
7247            });
7248        }
7249        _ => {
7250            let buffer_handle = if buffers.is_empty() || rng.random_bool(0.4) {
7251                let mut base_text = util::RandomCharIter::new(&mut rng)
7252                    .take(256)
7253                    .collect::<String>();
7254
7255                let buffer = cx.new(|cx| Buffer::local(base_text.clone(), cx));
7256                text::LineEnding::normalize(&mut base_text);
7257                base_texts.insert(
7258                    buffer.read_with(cx, |buffer, _| buffer.remote_id()),
7259                    base_text,
7260                );
7261                buffers.push(buffer);
7262                buffers.last().unwrap()
7263            } else {
7264                buffers.choose(&mut rng).unwrap()
7265            };
7266
7267            let prev_excerpt_id = multibuffer
7268                .read_with(cx, |multibuffer, cx| multibuffer.excerpt_ids())
7269                .choose(&mut rng)
7270                .copied()
7271                .unwrap_or(ExcerptId::max());
7272
7273            let range = buffer_handle.read_with(cx, |buffer, _| {
7274                let end_row = rng.random_range(0..=buffer.max_point().row);
7275                let start_row = rng.random_range(0..=end_row);
7276                let end_ix = buffer.point_to_offset(Point::new(end_row, 0));
7277                let start_ix = buffer.point_to_offset(Point::new(start_row, 0));
7278
7279                log::info!(
7280                    "Inserting excerpt for buffer {}: {:?}[{:?}] = {:?}",
7281                    buffer.remote_id(),
7282                    buffer.text(),
7283                    start_ix..end_ix,
7284                    &buffer.text()[start_ix..end_ix]
7285                );
7286
7287                start_ix..end_ix
7288            });
7289
7290            multibuffer.update(cx, |multibuffer, cx| {
7291                let id = buffer_handle.read(cx).remote_id();
7292                if multibuffer.diff_for(id).is_none() {
7293                    let base_text = base_texts.get(&id).unwrap();
7294                    let diff =
7295                        cx.new(|cx| BufferDiff::new_with_base_text(base_text, buffer_handle, cx));
7296                    multibuffer.add_diff(diff, cx)
7297                }
7298            });
7299
7300            multibuffer.update(cx, |multibuffer, cx| {
7301                multibuffer
7302                    .insert_excerpts_after(
7303                        prev_excerpt_id,
7304                        buffer_handle.clone(),
7305                        [ExcerptRange::new(range.clone())],
7306                        cx,
7307                    )
7308                    .pop()
7309                    .unwrap()
7310            });
7311        }
7312    }
7313}