multi_buffer.rs

   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::{self, AddAssign, 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
 173/// A zero-indexed point in a multibuffer consisting of a row and column.
 174#[derive(Copy, Clone, Default, Eq, Ord, PartialOrd, PartialEq)]
 175pub struct MultiBufferPoint(Point);
 176
 177impl fmt::Debug for MultiBufferPoint {
 178    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 179        f.write_fmt(format_args!(
 180            "MultiBufferPoint({}, {})",
 181            self.row().0,
 182            self.column()
 183        ))
 184    }
 185}
 186
 187impl ops::Add for MultiBufferPoint {
 188    type Output = Self;
 189
 190    fn add(self, other: Self) -> Self::Output {
 191        MultiBufferPoint(self.0 + other.0)
 192    }
 193}
 194
 195impl ops::AddAssign for MultiBufferPoint {
 196    fn add_assign(&mut self, other: Self) {
 197        self.0 += other.0;
 198    }
 199}
 200
 201impl ops::Sub for MultiBufferPoint {
 202    type Output = Self;
 203
 204    fn sub(self, other: Self) -> Self::Output {
 205        MultiBufferPoint(self.0 - other.0)
 206    }
 207}
 208
 209impl MultiBufferPoint {
 210    pub const MAX: Self = Self(Point::MAX);
 211
 212    pub fn new(row: MultiBufferRow, column: u32) -> Self {
 213        Self(Point::new(row.0, column))
 214    }
 215
 216    pub fn zero() -> Self {
 217        Self::new(MultiBufferRow(0), 0)
 218    }
 219
 220    pub fn is_zero(&self) -> bool {
 221        self.0.is_zero()
 222    }
 223
 224    pub fn row(self) -> MultiBufferRow {
 225        MultiBufferRow(self.0.row)
 226    }
 227
 228    pub fn column(self) -> u32 {
 229        self.0.column
 230    }
 231
 232    pub fn row_mut(&mut self) -> &mut u32 {
 233        &mut self.0.row
 234    }
 235
 236    pub fn column_mut(&mut self) -> &mut u32 {
 237        &mut self.0.column
 238    }
 239
 240    pub fn from_point(point: Point) -> Self {
 241        Self(point)
 242    }
 243
 244    // pub fn to_point(self, map: &DisplaySnapshot) -> Point {
 245    //     map.display_point_to_point(self, Bias::Left)
 246    // }
 247
 248    // pub fn to_offset(self, map: &DisplaySnapshot, bias: Bias) -> usize {
 249    //     let wrap_point = map.block_snapshot.to_wrap_point(self.0, bias);
 250    //     let tab_point = map.wrap_snapshot().to_tab_point(wrap_point);
 251    //     let fold_point = map.tab_snapshot().to_fold_point(tab_point, bias).0;
 252    //     let inlay_point = fold_point.to_inlay_point(map.fold_snapshot());
 253    //     map.inlay_snapshot()
 254    //         .to_buffer_offset(map.inlay_snapshot().to_offset(inlay_point))
 255    // }
 256}
 257
 258type ExcerptOffset = TypedOffset<Excerpt>;
 259type ExcerptPoint = TypedPoint<Excerpt>;
 260
 261#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 262#[serde(transparent)]
 263pub struct MultiBufferRow(pub u32);
 264
 265impl MultiBufferRow {
 266    pub const MIN: Self = Self(0);
 267    pub const MAX: Self = Self(u32::MAX);
 268}
 269
 270impl std::ops::Add<usize> for MultiBufferRow {
 271    type Output = Self;
 272
 273    fn add(self, rhs: usize) -> Self::Output {
 274        MultiBufferRow(self.0 + rhs as u32)
 275    }
 276}
 277
 278impl std::ops::Sub<usize> for MultiBufferRow {
 279    type Output = Self;
 280
 281    fn sub(self, rhs: usize) -> Self::Output {
 282        MultiBufferRow(self.0 - rhs as u32)
 283    }
 284}
 285impl std::ops::Add for MultiBufferRow {
 286    type Output = Self;
 287
 288    fn add(self, rhs: Self) -> Self::Output {
 289        MultiBufferRow(self.0 + rhs.0)
 290    }
 291}
 292
 293impl std::ops::Sub<Self> for MultiBufferRow {
 294    type Output = Self;
 295
 296    fn sub(self, rhs: Self) -> Self::Output {
 297        MultiBufferRow(self.0 - rhs.0)
 298    }
 299}
 300
 301impl fmt::Display for MultiBufferRow {
 302    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 303        write!(f, "{}", self.0)
 304    }
 305}
 306
 307pub trait ToOffset: 'static + fmt::Debug {
 308    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 309    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 310}
 311
 312pub trait ToPoint: 'static + fmt::Debug {
 313    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferPoint;
 314    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 315}
 316
 317struct BufferState {
 318    buffer: Entity<Buffer>,
 319    last_version: RefCell<clock::Global>,
 320    last_non_text_state_update_count: Cell<usize>,
 321    excerpts: Vec<Locator>,
 322    _subscriptions: [gpui::Subscription; 2],
 323}
 324
 325struct DiffState {
 326    diff: Entity<BufferDiff>,
 327    _subscription: gpui::Subscription,
 328}
 329
 330impl DiffState {
 331    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 332        DiffState {
 333            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 334                BufferDiffEvent::DiffChanged { changed_range } => {
 335                    if let Some(changed_range) = changed_range.clone() {
 336                        this.buffer_diff_changed(diff, changed_range, cx)
 337                    }
 338                    cx.emit(Event::BufferDiffChanged);
 339                }
 340                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 341                _ => {}
 342            }),
 343            diff,
 344        }
 345    }
 346}
 347
 348/// The contents of a [`MultiBuffer`] at a single point in time.
 349#[derive(Clone, Default)]
 350pub struct MultiBufferSnapshot {
 351    excerpts: SumTree<Excerpt>,
 352    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 353    diff_transforms: SumTree<DiffTransform>,
 354    non_text_state_update_count: usize,
 355    edit_count: usize,
 356    is_dirty: bool,
 357    has_deleted_file: bool,
 358    has_conflict: bool,
 359    /// immutable fields
 360    singleton: bool,
 361    excerpt_ids: SumTree<ExcerptIdMapping>,
 362    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 363    trailing_excerpt_update_count: usize,
 364    all_diff_hunks_expanded: bool,
 365    show_headers: bool,
 366}
 367
 368#[derive(Debug, Clone)]
 369enum DiffTransform {
 370    BufferContent {
 371        summary: TextSummary,
 372        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 373    },
 374    DeletedHunk {
 375        summary: TextSummary,
 376        buffer_id: BufferId,
 377        hunk_info: DiffTransformHunkInfo,
 378        base_text_byte_range: Range<usize>,
 379        has_trailing_newline: bool,
 380    },
 381}
 382
 383#[derive(Clone, Copy, Debug)]
 384struct DiffTransformHunkInfo {
 385    excerpt_id: ExcerptId,
 386    hunk_start_anchor: text::Anchor,
 387    hunk_secondary_status: DiffHunkSecondaryStatus,
 388}
 389
 390impl Eq for DiffTransformHunkInfo {}
 391
 392impl PartialEq for DiffTransformHunkInfo {
 393    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 394        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 395    }
 396}
 397
 398impl std::hash::Hash for DiffTransformHunkInfo {
 399    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 400        self.excerpt_id.hash(state);
 401        self.hunk_start_anchor.hash(state);
 402    }
 403}
 404
 405#[derive(Clone)]
 406pub struct ExcerptInfo {
 407    pub id: ExcerptId,
 408    pub buffer: BufferSnapshot,
 409    pub buffer_id: BufferId,
 410    pub range: ExcerptRange<text::Anchor>,
 411    pub end_row: MultiBufferRow,
 412}
 413
 414impl std::fmt::Debug for ExcerptInfo {
 415    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 416        f.debug_struct(type_name::<Self>())
 417            .field("id", &self.id)
 418            .field("buffer_id", &self.buffer_id)
 419            .field("path", &self.buffer.file().map(|f| f.path()))
 420            .field("range", &self.range)
 421            .finish()
 422    }
 423}
 424
 425/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 426#[derive(Debug)]
 427pub struct ExcerptBoundary {
 428    pub prev: Option<ExcerptInfo>,
 429    pub next: ExcerptInfo,
 430    /// The row in the `MultiBuffer` where the boundary is located
 431    pub row: MultiBufferRow,
 432}
 433
 434impl ExcerptBoundary {
 435    pub fn starts_new_buffer(&self) -> bool {
 436        match (self.prev.as_ref(), &self.next) {
 437            (None, _) => true,
 438            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 439        }
 440    }
 441}
 442
 443#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 444pub struct ExpandInfo {
 445    pub direction: ExpandExcerptDirection,
 446    pub excerpt_id: ExcerptId,
 447}
 448
 449#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 450pub struct RowInfo {
 451    pub buffer_id: Option<BufferId>,
 452    pub buffer_row: Option<u32>,
 453    pub multibuffer_row: Option<MultiBufferRow>,
 454    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 455    pub expand_info: Option<ExpandInfo>,
 456}
 457
 458/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 459#[derive(Clone)]
 460struct Excerpt {
 461    /// The unique identifier for this excerpt
 462    id: ExcerptId,
 463    /// The location of the excerpt in the [`MultiBuffer`]
 464    locator: Locator,
 465    /// The buffer being excerpted
 466    buffer_id: BufferId,
 467    /// A snapshot of the buffer being excerpted
 468    buffer: BufferSnapshot,
 469    /// The range of the buffer to be shown in the excerpt
 470    range: ExcerptRange<text::Anchor>,
 471    /// The last row in the excerpted slice of the buffer
 472    max_buffer_row: BufferRow,
 473    /// A summary of the text in the excerpt
 474    text_summary: TextSummary,
 475    has_trailing_newline: bool,
 476}
 477
 478/// A public view into an `Excerpt` in a [`MultiBuffer`].
 479///
 480/// Contains methods for getting the [`Buffer`] of the excerpt,
 481/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 482#[derive(Clone)]
 483pub struct MultiBufferExcerpt<'a> {
 484    excerpt: &'a Excerpt,
 485    diff_transforms: sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<usize, usize>>,
 486    offset: usize,
 487    excerpt_offset: ExcerptDimension<usize>,
 488    buffer_offset: usize,
 489}
 490
 491#[derive(Clone, Debug)]
 492struct ExcerptIdMapping {
 493    id: ExcerptId,
 494    locator: Locator,
 495}
 496
 497/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 498/// These ranges are relative to the buffer itself
 499#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 500pub struct ExcerptRange<T> {
 501    /// The full range of text to be shown in the excerpt.
 502    pub context: Range<T>,
 503    /// The primary range of text to be highlighted in the excerpt.
 504    /// In a multi-buffer search, this would be the text that matched the search
 505    pub primary: Range<T>,
 506}
 507
 508impl<T: Clone> ExcerptRange<T> {
 509    pub fn new(context: Range<T>) -> Self {
 510        Self {
 511            context: context.clone(),
 512            primary: context,
 513        }
 514    }
 515}
 516
 517#[derive(Clone, Debug, Default)]
 518pub struct ExcerptSummary {
 519    excerpt_id: ExcerptId,
 520    /// The location of the last [`Excerpt`] being summarized
 521    excerpt_locator: Locator,
 522    widest_line_number: u32,
 523    text: TextSummary,
 524}
 525
 526#[derive(Debug, Clone)]
 527pub struct DiffTransformSummary {
 528    input: TextSummary,
 529    output: TextSummary,
 530}
 531
 532#[derive(Clone)]
 533pub struct MultiBufferRows<'a> {
 534    point: MultiBufferPoint,
 535    is_empty: bool,
 536    is_singleton: bool,
 537    cursor: MultiBufferCursor<'a, Point, MultiBufferPoint>,
 538}
 539
 540pub struct MultiBufferChunks<'a> {
 541    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 542    diff_transforms: Cursor<'a, 'static, DiffTransform, Dimensions<usize, ExcerptOffset>>,
 543    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 544    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 545    buffer_chunk: Option<Chunk<'a>>,
 546    range: Range<usize>,
 547    excerpt_offset_range: Range<ExcerptOffset>,
 548    excerpt_chunks: Option<ExcerptChunks<'a>>,
 549    language_aware: bool,
 550}
 551
 552pub struct ReversedMultiBufferChunks<'a> {
 553    cursor: MultiBufferCursor<'a, usize, usize>,
 554    current_chunks: Option<rope::Chunks<'a>>,
 555    start: usize,
 556    offset: usize,
 557}
 558
 559pub struct MultiBufferBytes<'a> {
 560    range: Range<usize>,
 561    cursor: MultiBufferCursor<'a, usize, usize>,
 562    excerpt_bytes: Option<text::Bytes<'a>>,
 563    has_trailing_newline: bool,
 564    chunk: &'a [u8],
 565}
 566
 567pub struct ReversedMultiBufferBytes<'a> {
 568    range: Range<usize>,
 569    chunks: ReversedMultiBufferChunks<'a>,
 570    chunk: &'a [u8],
 571}
 572
 573struct DiffTransforms<LBD, MBD> {
 574    output_dimension: OutputDimension<MBD>,
 575    excerpt_dimension: ExcerptDimension<LBD>,
 576}
 577
 578impl<LBD, MBD> Clone for DiffTransforms<LBD, MBD>
 579where
 580    ExcerptDimension<LBD>: Clone,
 581    OutputDimension<MBD>: Clone,
 582{
 583    fn clone(&self) -> Self {
 584        Self {
 585            output_dimension: self.output_dimension.clone(),
 586            excerpt_dimension: self.excerpt_dimension.clone(),
 587        }
 588    }
 589}
 590
 591impl<'a, LBD, MBD> Dimension<'a, DiffTransformSummary> for DiffTransforms<LBD, MBD>
 592where
 593    ExcerptDimension<LBD>: Dimension<'a, DiffTransformSummary>,
 594    OutputDimension<MBD>: Dimension<'a, DiffTransformSummary>,
 595{
 596    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
 597        Self {
 598            output_dimension: OutputDimension::zero(cx),
 599            excerpt_dimension: ExcerptDimension::zero(cx),
 600        }
 601    }
 602
 603    fn add_summary(
 604        &mut self,
 605        summary: &'a DiffTransformSummary,
 606        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
 607    ) {
 608        self.output_dimension.add_summary(summary, cx);
 609        self.excerpt_dimension.add_summary(summary, cx);
 610    }
 611}
 612
 613#[derive(Clone)]
 614struct MultiBufferCursor<'a, LBD, MBD> {
 615    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<LBD>>,
 616    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<LBD, MBD>>,
 617    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 618    cached_region: Option<MultiBufferRegion<'a, LBD, MBD>>,
 619}
 620
 621#[derive(Clone)]
 622struct MultiBufferRegion<'a, LBD, MBD> {
 623    buffer: &'a BufferSnapshot,
 624    is_main_buffer: bool,
 625    diff_hunk_status: Option<DiffHunkStatus>,
 626    excerpt: &'a Excerpt,
 627    buffer_range: Range<LBD>,
 628    range: Range<MBD>,
 629    has_trailing_newline: bool,
 630}
 631
 632struct ExcerptChunks<'a> {
 633    excerpt_id: ExcerptId,
 634    content_chunks: BufferChunks<'a>,
 635    has_footer: bool,
 636}
 637
 638#[derive(Debug)]
 639struct BufferEdit {
 640    range: Range<usize>,
 641    new_text: Arc<str>,
 642    is_insertion: bool,
 643    original_indent_column: Option<u32>,
 644    excerpt_id: ExcerptId,
 645}
 646
 647#[derive(Clone, Copy, Debug, PartialEq)]
 648enum DiffChangeKind {
 649    BufferEdited,
 650    DiffUpdated { base_changed: bool },
 651    ExpandOrCollapseHunks { expand: bool },
 652}
 653
 654#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 655pub enum ExpandExcerptDirection {
 656    Up,
 657    Down,
 658    UpAndDown,
 659}
 660
 661impl ExpandExcerptDirection {
 662    pub fn should_expand_up(&self) -> bool {
 663        match self {
 664            ExpandExcerptDirection::Up => true,
 665            ExpandExcerptDirection::Down => false,
 666            ExpandExcerptDirection::UpAndDown => true,
 667        }
 668    }
 669
 670    pub fn should_expand_down(&self) -> bool {
 671        match self {
 672            ExpandExcerptDirection::Up => false,
 673            ExpandExcerptDirection::Down => true,
 674            ExpandExcerptDirection::UpAndDown => true,
 675        }
 676    }
 677}
 678
 679#[derive(Clone, Debug, PartialEq)]
 680pub struct IndentGuide {
 681    pub buffer_id: BufferId,
 682    pub start_row: MultiBufferRow,
 683    pub end_row: MultiBufferRow,
 684    pub depth: u32,
 685    pub tab_size: u32,
 686    pub settings: IndentGuideSettings,
 687}
 688
 689impl IndentGuide {
 690    pub fn indent_level(&self) -> u32 {
 691        self.depth * self.tab_size
 692    }
 693}
 694
 695impl MultiBuffer {
 696    pub fn new(capability: Capability) -> Self {
 697        Self::new_(
 698            capability,
 699            MultiBufferSnapshot {
 700                show_headers: true,
 701                ..MultiBufferSnapshot::default()
 702            },
 703        )
 704    }
 705
 706    pub fn without_headers(capability: Capability) -> Self {
 707        Self::new_(capability, Default::default())
 708    }
 709
 710    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 711        let mut this = Self::new_(
 712            buffer.read(cx).capability(),
 713            MultiBufferSnapshot {
 714                singleton: true,
 715                ..MultiBufferSnapshot::default()
 716            },
 717        );
 718        this.singleton = true;
 719        this.push_excerpts(
 720            buffer,
 721            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 722            cx,
 723        );
 724        this
 725    }
 726
 727    #[inline]
 728    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
 729        Self {
 730            snapshot: RefCell::new(snapshot),
 731            buffers: Default::default(),
 732            diffs: HashMap::default(),
 733            subscriptions: Topic::default(),
 734            singleton: false,
 735            capability,
 736            title: None,
 737            excerpts_by_path: Default::default(),
 738            paths_by_excerpt: Default::default(),
 739            buffer_changed_since_sync: Default::default(),
 740            history: History::default(),
 741        }
 742    }
 743
 744    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 745        let mut buffers = HashMap::default();
 746        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 747        for (buffer_id, buffer_state) in self.buffers.iter() {
 748            buffer_state.buffer.update(new_cx, |buffer, _| {
 749                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 750            });
 751            buffers.insert(
 752                *buffer_id,
 753                BufferState {
 754                    buffer: buffer_state.buffer.clone(),
 755                    last_version: buffer_state.last_version.clone(),
 756                    last_non_text_state_update_count: buffer_state
 757                        .last_non_text_state_update_count
 758                        .clone(),
 759                    excerpts: buffer_state.excerpts.clone(),
 760                    _subscriptions: [
 761                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 762                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 763                    ],
 764                },
 765            );
 766        }
 767        let mut diff_bases = HashMap::default();
 768        for (buffer_id, diff) in self.diffs.iter() {
 769            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 770        }
 771        Self {
 772            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 773            buffers: buffers,
 774            excerpts_by_path: Default::default(),
 775            paths_by_excerpt: Default::default(),
 776            diffs: diff_bases,
 777            subscriptions: Default::default(),
 778            singleton: self.singleton,
 779            capability: self.capability,
 780            history: self.history.clone(),
 781            title: self.title.clone(),
 782            buffer_changed_since_sync,
 783        }
 784    }
 785
 786    pub fn set_group_interval(&mut self, group_interval: Duration) {
 787        self.history.set_group_interval(group_interval);
 788    }
 789
 790    pub fn with_title(mut self, title: String) -> Self {
 791        self.title = Some(title);
 792        self
 793    }
 794
 795    pub fn read_only(&self) -> bool {
 796        self.capability == Capability::ReadOnly
 797    }
 798
 799    /// Returns an up-to-date snapshot of the MultiBuffer.
 800    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 801        self.sync(cx);
 802        self.snapshot.borrow().clone()
 803    }
 804
 805    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 806        self.sync(cx);
 807        self.snapshot.borrow()
 808    }
 809
 810    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 811        if self.singleton {
 812            Some(self.buffers.values().next().unwrap().buffer.clone())
 813        } else {
 814            None
 815        }
 816    }
 817
 818    pub fn is_singleton(&self) -> bool {
 819        self.singleton
 820    }
 821
 822    pub fn subscribe(&mut self) -> Subscription {
 823        self.subscriptions.subscribe()
 824    }
 825
 826    pub fn is_dirty(&self, cx: &App) -> bool {
 827        self.read(cx).is_dirty()
 828    }
 829
 830    pub fn has_deleted_file(&self, cx: &App) -> bool {
 831        self.read(cx).has_deleted_file()
 832    }
 833
 834    pub fn has_conflict(&self, cx: &App) -> bool {
 835        self.read(cx).has_conflict()
 836    }
 837
 838    // The `is_empty` signature doesn't match what clippy expects
 839    #[allow(clippy::len_without_is_empty)]
 840    pub fn len(&self, cx: &App) -> usize {
 841        self.read(cx).len()
 842    }
 843
 844    pub fn is_empty(&self) -> bool {
 845        self.buffers.is_empty()
 846    }
 847
 848    pub fn edit<I, S, T>(
 849        &mut self,
 850        edits: I,
 851        autoindent_mode: Option<AutoindentMode>,
 852        cx: &mut Context<Self>,
 853    ) where
 854        I: IntoIterator<Item = (Range<S>, T)>,
 855        S: ToOffset,
 856        T: Into<Arc<str>>,
 857    {
 858        if self.read_only() || self.buffers.is_empty() {
 859            return;
 860        }
 861        self.sync_mut(cx);
 862        let edits = edits
 863            .into_iter()
 864            .map(|(range, new_text)| {
 865                let mut range = range.start.to_offset(self.snapshot.get_mut())
 866                    ..range.end.to_offset(self.snapshot.get_mut());
 867                if range.start > range.end {
 868                    mem::swap(&mut range.start, &mut range.end);
 869                }
 870                (range, new_text.into())
 871            })
 872            .collect::<Vec<_>>();
 873
 874        return edit_internal(self, edits, autoindent_mode, cx);
 875
 876        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 877        fn edit_internal(
 878            this: &mut MultiBuffer,
 879            edits: Vec<(Range<usize>, Arc<str>)>,
 880            mut autoindent_mode: Option<AutoindentMode>,
 881            cx: &mut Context<MultiBuffer>,
 882        ) {
 883            let original_indent_columns = match &mut autoindent_mode {
 884                Some(AutoindentMode::Block {
 885                    original_indent_columns,
 886                }) => mem::take(original_indent_columns),
 887                _ => Default::default(),
 888            };
 889
 890            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
 891                edits,
 892                this.snapshot.get_mut(),
 893                &original_indent_columns,
 894            );
 895
 896            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
 897            for (buffer_id, mut edits) in buffer_edits {
 898                buffer_ids.push(buffer_id);
 899                edits.sort_by_key(|edit| edit.range.start);
 900                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
 901                    let mut edits = edits.into_iter().peekable();
 902                    let mut insertions = Vec::new();
 903                    let mut original_indent_columns = Vec::new();
 904                    let mut deletions = Vec::new();
 905                    let empty_str: Arc<str> = Arc::default();
 906                    while let Some(BufferEdit {
 907                        mut range,
 908                        mut new_text,
 909                        mut is_insertion,
 910                        original_indent_column,
 911                        excerpt_id,
 912                    }) = edits.next()
 913                    {
 914                        while let Some(BufferEdit {
 915                            range: next_range,
 916                            is_insertion: next_is_insertion,
 917                            new_text: next_new_text,
 918                            excerpt_id: next_excerpt_id,
 919                            ..
 920                        }) = edits.peek()
 921                        {
 922                            if range.end >= next_range.start {
 923                                range.end = cmp::max(next_range.end, range.end);
 924                                is_insertion |= *next_is_insertion;
 925                                if excerpt_id == *next_excerpt_id {
 926                                    new_text = format!("{new_text}{next_new_text}").into();
 927                                }
 928                                edits.next();
 929                            } else {
 930                                break;
 931                            }
 932                        }
 933
 934                        if is_insertion {
 935                            original_indent_columns.push(original_indent_column);
 936                            insertions.push((
 937                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 938                                new_text.clone(),
 939                            ));
 940                        } else if !range.is_empty() {
 941                            deletions.push((
 942                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 943                                empty_str.clone(),
 944                            ));
 945                        }
 946                    }
 947
 948                    let deletion_autoindent_mode =
 949                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 950                            Some(AutoindentMode::Block {
 951                                original_indent_columns: Default::default(),
 952                            })
 953                        } else {
 954                            autoindent_mode.clone()
 955                        };
 956                    let insertion_autoindent_mode =
 957                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 958                            Some(AutoindentMode::Block {
 959                                original_indent_columns,
 960                            })
 961                        } else {
 962                            autoindent_mode.clone()
 963                        };
 964
 965                    buffer.edit(deletions, deletion_autoindent_mode, cx);
 966                    buffer.edit(insertions, insertion_autoindent_mode, cx);
 967                })
 968            }
 969
 970            cx.emit(Event::ExcerptsEdited {
 971                excerpt_ids: edited_excerpt_ids,
 972                buffer_ids,
 973            });
 974        }
 975    }
 976
 977    fn convert_edits_to_buffer_edits(
 978        edits: Vec<(Range<usize>, Arc<str>)>,
 979        snapshot: &MultiBufferSnapshot,
 980        original_indent_columns: &[Option<u32>],
 981    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 982        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 983        let mut edited_excerpt_ids = Vec::new();
 984        let mut cursor = snapshot.cursor::<usize, usize>();
 985        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 986            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 987
 988            cursor.seek(&range.start);
 989            let mut start_region = cursor.region().expect("start offset out of bounds");
 990            if !start_region.is_main_buffer {
 991                cursor.next();
 992                if let Some(region) = cursor.region() {
 993                    start_region = region;
 994                } else {
 995                    continue;
 996                }
 997            }
 998
 999            if range.end < start_region.range.start {
1000                continue;
1001            }
1002
1003            if range.end > start_region.range.end {
1004                cursor.seek_forward(&range.end);
1005            }
1006            let mut end_region = cursor.region().expect("end offset out of bounds");
1007            if !end_region.is_main_buffer {
1008                cursor.prev();
1009                if let Some(region) = cursor.region() {
1010                    end_region = region;
1011                } else {
1012                    continue;
1013                }
1014            }
1015
1016            if range.start > end_region.range.end {
1017                continue;
1018            }
1019
1020            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1021            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1022            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1023                .min(start_region.buffer_range.end);
1024            let buffer_end =
1025                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1026
1027            if start_region.excerpt.id == end_region.excerpt.id {
1028                if start_region.is_main_buffer {
1029                    edited_excerpt_ids.push(start_region.excerpt.id);
1030                    buffer_edits
1031                        .entry(start_region.buffer.remote_id())
1032                        .or_default()
1033                        .push(BufferEdit {
1034                            range: buffer_start..buffer_end,
1035                            new_text,
1036                            is_insertion: true,
1037                            original_indent_column,
1038                            excerpt_id: start_region.excerpt.id,
1039                        });
1040                }
1041            } else {
1042                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1043                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1044                if start_region.is_main_buffer {
1045                    edited_excerpt_ids.push(start_region.excerpt.id);
1046                    buffer_edits
1047                        .entry(start_region.buffer.remote_id())
1048                        .or_default()
1049                        .push(BufferEdit {
1050                            range: start_excerpt_range,
1051                            new_text: new_text.clone(),
1052                            is_insertion: true,
1053                            original_indent_column,
1054                            excerpt_id: start_region.excerpt.id,
1055                        });
1056                }
1057                if end_region.is_main_buffer {
1058                    edited_excerpt_ids.push(end_region.excerpt.id);
1059                    buffer_edits
1060                        .entry(end_region.buffer.remote_id())
1061                        .or_default()
1062                        .push(BufferEdit {
1063                            range: end_excerpt_range,
1064                            new_text: new_text.clone(),
1065                            is_insertion: false,
1066                            original_indent_column,
1067                            excerpt_id: end_region.excerpt.id,
1068                        });
1069                }
1070
1071                cursor.seek(&range.start);
1072                cursor.next_excerpt();
1073                while let Some(region) = cursor.region() {
1074                    if region.excerpt.id == end_region.excerpt.id {
1075                        break;
1076                    }
1077                    if region.is_main_buffer {
1078                        edited_excerpt_ids.push(region.excerpt.id);
1079                        buffer_edits
1080                            .entry(region.buffer.remote_id())
1081                            .or_default()
1082                            .push(BufferEdit {
1083                                range: region.buffer_range,
1084                                new_text: new_text.clone(),
1085                                is_insertion: false,
1086                                original_indent_column,
1087                                excerpt_id: region.excerpt.id,
1088                            });
1089                    }
1090                    cursor.next_excerpt();
1091                }
1092            }
1093        }
1094        (buffer_edits, edited_excerpt_ids)
1095    }
1096
1097    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1098    where
1099        I: IntoIterator<Item = Range<S>>,
1100        S: ToOffset,
1101    {
1102        if self.read_only() || self.buffers.is_empty() {
1103            return;
1104        }
1105        self.sync_mut(cx);
1106        let empty = Arc::<str>::from("");
1107        let edits = ranges
1108            .into_iter()
1109            .map(|range| {
1110                let mut range = range.start.to_offset(self.snapshot.get_mut())
1111                    ..range.end.to_offset(&self.snapshot.get_mut());
1112                if range.start > range.end {
1113                    mem::swap(&mut range.start, &mut range.end);
1114                }
1115                (range, empty.clone())
1116            })
1117            .collect::<Vec<_>>();
1118
1119        return autoindent_ranges_internal(self, edits, cx);
1120
1121        fn autoindent_ranges_internal(
1122            this: &mut MultiBuffer,
1123            edits: Vec<(Range<usize>, Arc<str>)>,
1124            cx: &mut Context<MultiBuffer>,
1125        ) {
1126            let (buffer_edits, edited_excerpt_ids) =
1127                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1128
1129            let mut buffer_ids = Vec::new();
1130            for (buffer_id, mut edits) in buffer_edits {
1131                buffer_ids.push(buffer_id);
1132                edits.sort_unstable_by_key(|edit| edit.range.start);
1133
1134                let mut ranges: Vec<Range<usize>> = Vec::new();
1135                for edit in edits {
1136                    if let Some(last_range) = ranges.last_mut()
1137                        && edit.range.start <= last_range.end
1138                    {
1139                        last_range.end = last_range.end.max(edit.range.end);
1140                        continue;
1141                    }
1142                    ranges.push(edit.range);
1143                }
1144
1145                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1146                    buffer.autoindent_ranges(ranges, cx);
1147                })
1148            }
1149
1150            cx.emit(Event::ExcerptsEdited {
1151                excerpt_ids: edited_excerpt_ids,
1152                buffer_ids,
1153            });
1154        }
1155    }
1156
1157    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1158    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1159    /// Panics if the given position is invalid.
1160    pub fn insert_empty_line(
1161        &mut self,
1162        position: impl ToPoint,
1163        space_above: bool,
1164        space_below: bool,
1165        cx: &mut Context<Self>,
1166    ) -> MultiBufferPoint {
1167        let multibuffer_point = position.to_point(&self.read(cx));
1168        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1169        self.start_transaction(cx);
1170        let empty_line_start = buffer.update(cx, |buffer, cx| {
1171            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1172        });
1173        self.end_transaction(cx);
1174        multibuffer_point + MultiBufferPoint(empty_line_start - buffer_point)
1175    }
1176
1177    pub fn set_active_selections(
1178        &self,
1179        selections: &[Selection<Anchor>],
1180        line_mode: bool,
1181        cursor_shape: CursorShape,
1182        cx: &mut Context<Self>,
1183    ) {
1184        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1185            Default::default();
1186        let snapshot = self.read(cx);
1187        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1188        for selection in selections {
1189            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1190            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1191
1192            cursor.seek(&Some(start_locator), Bias::Left);
1193            while let Some(excerpt) = cursor.item()
1194                && excerpt.locator <= *end_locator
1195            {
1196                let mut start = excerpt.range.context.start;
1197                let mut end = excerpt.range.context.end;
1198                if excerpt.id == selection.start.excerpt_id {
1199                    start = selection.start.text_anchor;
1200                }
1201                if excerpt.id == selection.end.excerpt_id {
1202                    end = selection.end.text_anchor;
1203                }
1204                selections_by_buffer
1205                    .entry(excerpt.buffer_id)
1206                    .or_default()
1207                    .push(Selection {
1208                        id: selection.id,
1209                        start,
1210                        end,
1211                        reversed: selection.reversed,
1212                        goal: selection.goal,
1213                    });
1214
1215                cursor.next();
1216            }
1217        }
1218
1219        for (buffer_id, buffer_state) in self.buffers.iter() {
1220            if !selections_by_buffer.contains_key(buffer_id) {
1221                buffer_state
1222                    .buffer
1223                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1224            }
1225        }
1226
1227        for (buffer_id, mut selections) in selections_by_buffer {
1228            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1229                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1230                let mut selections = selections.into_iter().peekable();
1231                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1232                    let mut selection = selections.next()?;
1233                    while let Some(next_selection) = selections.peek() {
1234                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1235                            let next_selection = selections.next().unwrap();
1236                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1237                                selection.end = next_selection.end;
1238                            }
1239                        } else {
1240                            break;
1241                        }
1242                    }
1243                    Some(selection)
1244                }));
1245                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1246            });
1247        }
1248    }
1249
1250    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1251        for buffer in self.buffers.values() {
1252            buffer
1253                .buffer
1254                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1255        }
1256    }
1257
1258    pub fn push_excerpts<O>(
1259        &mut self,
1260        buffer: Entity<Buffer>,
1261        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1262        cx: &mut Context<Self>,
1263    ) -> Vec<ExcerptId>
1264    where
1265        O: text::ToOffset,
1266    {
1267        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1268    }
1269
1270    fn merge_excerpt_ranges<'a>(
1271        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1272    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1273        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1274        let mut counts: Vec<usize> = Vec::new();
1275        for range in expanded_ranges {
1276            if let Some(last_range) = merged_ranges.last_mut() {
1277                debug_assert!(
1278                    last_range.context.start <= range.context.start,
1279                    "Last range: {last_range:?} Range: {range:?}"
1280                );
1281                if last_range.context.end >= range.context.start
1282                    || last_range.context.end.row + 1 == range.context.start.row
1283                {
1284                    last_range.context.end = range.context.end.max(last_range.context.end);
1285                    *counts.last_mut().unwrap() += 1;
1286                    continue;
1287                }
1288            }
1289            merged_ranges.push(range.clone());
1290            counts.push(1);
1291        }
1292        (merged_ranges, counts)
1293    }
1294
1295    pub fn insert_excerpts_after<O>(
1296        &mut self,
1297        prev_excerpt_id: ExcerptId,
1298        buffer: Entity<Buffer>,
1299        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1300        cx: &mut Context<Self>,
1301    ) -> Vec<ExcerptId>
1302    where
1303        O: text::ToOffset,
1304    {
1305        let mut ids = Vec::new();
1306        let mut next_excerpt_id =
1307            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1308                last_entry.id.0 + 1
1309            } else {
1310                1
1311            };
1312        self.insert_excerpts_with_ids_after(
1313            prev_excerpt_id,
1314            buffer,
1315            ranges.into_iter().map(|range| {
1316                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1317                ids.push(id);
1318                (id, range)
1319            }),
1320            cx,
1321        );
1322        ids
1323    }
1324
1325    pub fn insert_excerpts_with_ids_after<O>(
1326        &mut self,
1327        prev_excerpt_id: ExcerptId,
1328        buffer: Entity<Buffer>,
1329        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1330        cx: &mut Context<Self>,
1331    ) where
1332        O: text::ToOffset,
1333    {
1334        assert_eq!(self.history.transaction_depth(), 0);
1335        let mut ranges = ranges.into_iter().peekable();
1336        if ranges.peek().is_none() {
1337            return Default::default();
1338        }
1339
1340        self.sync_mut(cx);
1341
1342        let buffer_snapshot = buffer.read(cx).snapshot();
1343        let buffer_id = buffer_snapshot.remote_id();
1344
1345        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1346            self.buffer_changed_since_sync.replace(true);
1347            buffer.update(cx, |buffer, _| {
1348                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1349            });
1350            BufferState {
1351                last_version: RefCell::new(buffer_snapshot.version().clone()),
1352                last_non_text_state_update_count: Cell::new(
1353                    buffer_snapshot.non_text_state_update_count(),
1354                ),
1355                excerpts: Default::default(),
1356                _subscriptions: [
1357                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1358                    cx.subscribe(&buffer, Self::on_buffer_event),
1359                ],
1360                buffer: buffer.clone(),
1361            }
1362        });
1363
1364        let mut snapshot = self.snapshot.get_mut();
1365
1366        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1367        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1368        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1369        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1370        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1371
1372        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1373        new_excerpts.update_last(
1374            |excerpt| {
1375                excerpt.has_trailing_newline = true;
1376            },
1377            (),
1378        );
1379
1380        let next_locator = if let Some(excerpt) = cursor.item() {
1381            excerpt.locator.clone()
1382        } else {
1383            Locator::max()
1384        };
1385
1386        let mut excerpts = Vec::new();
1387        while let Some((id, range)) = ranges.next() {
1388            let locator = Locator::between(&prev_locator, &next_locator);
1389            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1390                buffer_state.excerpts.insert(ix, locator.clone());
1391            }
1392            let range = ExcerptRange {
1393                context: buffer_snapshot.anchor_before(&range.context.start)
1394                    ..buffer_snapshot.anchor_after(&range.context.end),
1395                primary: buffer_snapshot.anchor_before(&range.primary.start)
1396                    ..buffer_snapshot.anchor_after(&range.primary.end),
1397            };
1398            excerpts.push((id, range.clone()));
1399            let excerpt = Excerpt::new(
1400                id,
1401                locator.clone(),
1402                buffer_id,
1403                buffer_snapshot.clone(),
1404                range,
1405                ranges.peek().is_some() || cursor.item().is_some(),
1406            );
1407            new_excerpts.push(excerpt, ());
1408            prev_locator = locator.clone();
1409
1410            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1411                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1412            }
1413            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1414        }
1415
1416        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
1417
1418        let suffix = cursor.suffix();
1419        let changed_trailing_excerpt = suffix.is_empty();
1420        new_excerpts.append(suffix, ());
1421        drop(cursor);
1422        snapshot.excerpts = new_excerpts;
1423        snapshot.excerpt_ids = new_excerpt_ids;
1424        if changed_trailing_excerpt {
1425            snapshot.trailing_excerpt_update_count += 1;
1426        }
1427
1428        let edits = Self::sync_diff_transforms(
1429            &mut snapshot,
1430            vec![Edit {
1431                old: edit_start..edit_start,
1432                new: edit_start..edit_end,
1433            }],
1434            DiffChangeKind::BufferEdited,
1435        );
1436        if !edits.is_empty() {
1437            self.subscriptions.publish(edits);
1438        }
1439
1440        cx.emit(Event::Edited {
1441            edited_buffer: None,
1442        });
1443        cx.emit(Event::ExcerptsAdded {
1444            buffer,
1445            predecessor: prev_excerpt_id,
1446            excerpts,
1447        });
1448        cx.notify();
1449    }
1450
1451    pub fn clear(&mut self, cx: &mut Context<Self>) {
1452        self.sync_mut(cx);
1453        let ids = self.excerpt_ids();
1454        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1455        self.excerpts_by_path.clear();
1456        self.paths_by_excerpt.clear();
1457        let MultiBufferSnapshot {
1458            excerpts,
1459            diffs: _,
1460            diff_transforms: _,
1461            non_text_state_update_count: _,
1462            edit_count: _,
1463            is_dirty,
1464            has_deleted_file,
1465            has_conflict,
1466            singleton: _,
1467            excerpt_ids: _,
1468            replaced_excerpts,
1469            trailing_excerpt_update_count,
1470            all_diff_hunks_expanded: _,
1471            show_headers: _,
1472        } = self.snapshot.get_mut();
1473        let start = ExcerptOffset::new(0);
1474        let prev_len = ExcerptOffset::new(excerpts.summary().text.len);
1475        *excerpts = Default::default();
1476        *trailing_excerpt_update_count += 1;
1477        *is_dirty = false;
1478        *has_deleted_file = false;
1479        *has_conflict = false;
1480        replaced_excerpts.clear();
1481
1482        let edits = Self::sync_diff_transforms(
1483            self.snapshot.get_mut(),
1484            vec![Edit {
1485                old: start..prev_len,
1486                new: start..start,
1487            }],
1488            DiffChangeKind::BufferEdited,
1489        );
1490        if !edits.is_empty() {
1491            self.subscriptions.publish(edits);
1492        }
1493        cx.emit(Event::Edited {
1494            edited_buffer: None,
1495        });
1496        cx.emit(Event::ExcerptsRemoved {
1497            ids,
1498            removed_buffer_ids,
1499        });
1500        cx.notify();
1501    }
1502
1503    pub fn excerpts_for_buffer(
1504        &self,
1505        buffer_id: BufferId,
1506        cx: &App,
1507    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1508        let mut excerpts = Vec::new();
1509        let snapshot = self.read(cx);
1510        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1511        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1512            for locator in locators {
1513                cursor.seek_forward(&Some(locator), Bias::Left);
1514                if let Some(excerpt) = cursor.item()
1515                    && excerpt.locator == *locator
1516                {
1517                    excerpts.push((excerpt.id, excerpt.range.clone()));
1518                }
1519            }
1520        }
1521
1522        excerpts
1523    }
1524
1525    pub fn excerpt_ranges_for_buffer(
1526        &self,
1527        buffer_id: BufferId,
1528        cx: &App,
1529    ) -> Vec<Range<MultiBufferPoint>> {
1530        let snapshot = self.read(cx);
1531        let mut excerpts = snapshot
1532            .excerpts
1533            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
1534        let mut diff_transforms = snapshot
1535            .diff_transforms
1536            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<MultiBufferPoint>>>(());
1537        diff_transforms.next();
1538        let locators = self
1539            .buffers
1540            .get(&buffer_id)
1541            .into_iter()
1542            .flat_map(|state| &state.excerpts);
1543        let mut result = Vec::new();
1544        for locator in locators {
1545            excerpts.seek_forward(&Some(locator), Bias::Left);
1546            if let Some(excerpt) = excerpts.item()
1547                && excerpt.locator == *locator
1548            {
1549                let excerpt_start = excerpts.start().1.clone();
1550                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1551
1552                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1553                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
1554                let mut start = diff_transforms.start().1.0;
1555                start.add_distance(overshoot);
1556
1557                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1558                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
1559                let mut end = diff_transforms.start().1.0;
1560                end.add_distance(overshoot);
1561
1562                result.push(start..end)
1563            }
1564        }
1565        result
1566    }
1567
1568    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1569        self.snapshot
1570            .borrow()
1571            .excerpts
1572            .iter()
1573            .map(|entry| entry.buffer_id)
1574            .collect()
1575    }
1576
1577    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1578        self.snapshot
1579            .borrow()
1580            .excerpts
1581            .iter()
1582            .map(|entry| entry.id)
1583            .collect()
1584    }
1585
1586    pub fn excerpt_containing(
1587        &self,
1588        position: impl ToOffset,
1589        cx: &App,
1590    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1591        let snapshot = self.read(cx);
1592        let offset = position.to_offset(&snapshot);
1593
1594        let mut cursor = snapshot.cursor::<usize, usize>();
1595        cursor.seek(&offset);
1596        cursor
1597            .excerpt()
1598            .or_else(|| snapshot.excerpts.last())
1599            .map(|excerpt| {
1600                (
1601                    excerpt.id,
1602                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
1603                    excerpt.range.context.clone(),
1604                )
1605            })
1606    }
1607
1608    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1609        if let Some(buffer_id) = anchor.buffer_id {
1610            self.buffer(buffer_id)
1611        } else {
1612            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
1613            Some(buffer)
1614        }
1615    }
1616
1617    // If point is at the end of the buffer, the last excerpt is returned
1618    pub fn point_to_buffer_offset<T: ToOffset>(
1619        &self,
1620        point: T,
1621        cx: &App,
1622    ) -> Option<(Entity<Buffer>, usize)> {
1623        let snapshot = self.read(cx);
1624        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1625        Some((
1626            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1627            offset,
1628        ))
1629    }
1630
1631    // If point is at the end of the buffer, the last excerpt is returned
1632    pub fn point_to_buffer_point<T: ToPoint>(
1633        &self,
1634        point: T,
1635        cx: &App,
1636    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1637        let snapshot = self.read(cx);
1638        let (buffer, point, is_main_buffer) =
1639            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1640        Some((
1641            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1642            point,
1643            is_main_buffer,
1644        ))
1645    }
1646
1647    pub fn buffer_point_to_anchor(
1648        &self,
1649        buffer: &Entity<Buffer>,
1650        point: Point,
1651        cx: &App,
1652    ) -> Option<Anchor> {
1653        let mut found = None;
1654        let snapshot = buffer.read(cx).snapshot();
1655        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1656            let start = range.context.start.to_point(&snapshot);
1657            let end = range.context.end.to_point(&snapshot);
1658            if start <= point && point < end {
1659                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1660                break;
1661            }
1662            if point < start {
1663                found = Some((start, excerpt_id));
1664            }
1665            if point > end {
1666                found = Some((end, excerpt_id));
1667            }
1668        }
1669
1670        found.map(|(point, excerpt_id)| {
1671            let text_anchor = snapshot.anchor_after(point);
1672            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
1673        })
1674    }
1675
1676    pub fn remove_excerpts(
1677        &mut self,
1678        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1679        cx: &mut Context<Self>,
1680    ) {
1681        self.sync_mut(cx);
1682        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1683        if ids.is_empty() {
1684            return;
1685        }
1686        self.buffer_changed_since_sync.replace(true);
1687
1688        let mut snapshot = self.snapshot.get_mut();
1689        let mut new_excerpts = SumTree::default();
1690        let mut cursor = snapshot
1691            .excerpts
1692            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1693        let mut edits = Vec::new();
1694        let mut excerpt_ids = ids.iter().copied().peekable();
1695        let mut removed_buffer_ids = Vec::new();
1696
1697        while let Some(excerpt_id) = excerpt_ids.next() {
1698            self.paths_by_excerpt.remove(&excerpt_id);
1699            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1700            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1701            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
1702
1703            if let Some(mut excerpt) = cursor.item() {
1704                if excerpt.id != excerpt_id {
1705                    continue;
1706                }
1707                let mut old_start = cursor.start().1;
1708
1709                // Skip over the removed excerpt.
1710                'remove_excerpts: loop {
1711                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
1712                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1713                        if buffer_state.excerpts.is_empty() {
1714                            log::debug!(
1715                                "removing buffer and diff for buffer {}",
1716                                excerpt.buffer_id
1717                            );
1718                            self.buffers.remove(&excerpt.buffer_id);
1719                            removed_buffer_ids.push(excerpt.buffer_id);
1720                        }
1721                    }
1722                    cursor.next();
1723
1724                    // Skip over any subsequent excerpts that are also removed.
1725                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1726                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1727                        if let Some(next_excerpt) = cursor.item()
1728                            && next_excerpt.locator == *next_locator
1729                        {
1730                            excerpt_ids.next();
1731                            excerpt = next_excerpt;
1732                            continue 'remove_excerpts;
1733                        }
1734                    }
1735
1736                    break;
1737                }
1738
1739                // When removing the last excerpt, remove the trailing newline from
1740                // the previous excerpt.
1741                if cursor.item().is_none() && old_start.value > 0 {
1742                    old_start.value -= 1;
1743                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
1744                }
1745
1746                // Push an edit for the removal of this run of excerpts.
1747                let old_end = cursor.start().1;
1748                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1749                edits.push(Edit {
1750                    old: old_start..old_end,
1751                    new: new_start..new_start,
1752                });
1753            }
1754        }
1755        let suffix = cursor.suffix();
1756        let changed_trailing_excerpt = suffix.is_empty();
1757        new_excerpts.append(suffix, ());
1758        drop(cursor);
1759        snapshot.excerpts = new_excerpts;
1760        for buffer_id in &removed_buffer_ids {
1761            self.diffs.remove(buffer_id);
1762            snapshot.diffs.remove(buffer_id);
1763        }
1764
1765        if changed_trailing_excerpt {
1766            snapshot.trailing_excerpt_update_count += 1;
1767        }
1768
1769        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
1770        if !edits.is_empty() {
1771            self.subscriptions.publish(edits);
1772        }
1773        cx.emit(Event::Edited {
1774            edited_buffer: None,
1775        });
1776        cx.emit(Event::ExcerptsRemoved {
1777            ids,
1778            removed_buffer_ids,
1779        });
1780        cx.notify();
1781    }
1782
1783    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1784        &self,
1785        anchors: Anchors,
1786        cx: &mut Context<Self>,
1787    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1788        let mut error = None;
1789        let mut futures = Vec::new();
1790        for anchor in anchors {
1791            if let Some(buffer_id) = anchor.buffer_id {
1792                if let Some(buffer) = self.buffers.get(&buffer_id) {
1793                    buffer.buffer.update(cx, |buffer, _| {
1794                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1795                    });
1796                } else {
1797                    error = Some(anyhow!(
1798                        "buffer {buffer_id} is not part of this multi-buffer"
1799                    ));
1800                    break;
1801                }
1802            }
1803        }
1804        async move {
1805            if let Some(error) = error {
1806                Err(error)?;
1807            }
1808            for future in futures {
1809                future.await?;
1810            }
1811            Ok(())
1812        }
1813    }
1814
1815    pub fn text_anchor_for_position<T: ToOffset>(
1816        &self,
1817        position: T,
1818        cx: &App,
1819    ) -> Option<(Entity<Buffer>, language::Anchor)> {
1820        let snapshot = self.read(cx);
1821        let anchor = snapshot.anchor_before(position);
1822        let buffer = self.buffers.get(&anchor.buffer_id?)?.buffer.clone();
1823        Some((buffer, anchor.text_anchor))
1824    }
1825
1826    fn on_buffer_event(
1827        &mut self,
1828        buffer: Entity<Buffer>,
1829        event: &language::BufferEvent,
1830        cx: &mut Context<Self>,
1831    ) {
1832        use language::BufferEvent;
1833        cx.emit(match event {
1834            BufferEvent::Edited => Event::Edited {
1835                edited_buffer: Some(buffer),
1836            },
1837            BufferEvent::DirtyChanged => Event::DirtyChanged,
1838            BufferEvent::Saved => Event::Saved,
1839            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1840            BufferEvent::Reloaded => Event::Reloaded,
1841            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
1842            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
1843            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1844            BufferEvent::CapabilityChanged => {
1845                self.capability = buffer.read(cx).capability();
1846                return;
1847            }
1848            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1849        });
1850    }
1851
1852    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1853        let diff = diff.read(cx);
1854        let buffer_id = diff.buffer_id;
1855        let diff = diff.snapshot(cx);
1856        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
1857    }
1858
1859    fn buffer_diff_changed(
1860        &mut self,
1861        diff: Entity<BufferDiff>,
1862        range: Range<text::Anchor>,
1863        cx: &mut Context<Self>,
1864    ) {
1865        self.sync_mut(cx);
1866
1867        let diff = diff.read(cx);
1868        let buffer_id = diff.buffer_id;
1869        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
1870            return;
1871        };
1872        self.buffer_changed_since_sync.replace(true);
1873
1874        let buffer = buffer_state.buffer.read(cx);
1875        let diff_change_range = range.to_offset(buffer);
1876
1877        let new_diff = diff.snapshot(cx);
1878        let mut snapshot = self.snapshot.get_mut();
1879        let base_text_changed = snapshot
1880            .diffs
1881            .get(&buffer_id)
1882            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
1883
1884        snapshot.diffs.insert(buffer_id, new_diff);
1885
1886        let mut excerpt_edits = Vec::new();
1887        for locator in &buffer_state.excerpts {
1888            let mut cursor = snapshot
1889                .excerpts
1890                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
1891            cursor.seek_forward(&Some(locator), Bias::Left);
1892            if let Some(excerpt) = cursor.item()
1893                && excerpt.locator == *locator
1894            {
1895                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
1896                if diff_change_range.end < excerpt_buffer_range.start
1897                    || diff_change_range.start > excerpt_buffer_range.end
1898                {
1899                    continue;
1900                }
1901                let excerpt_start = cursor.start().1;
1902                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
1903                let diff_change_start_in_excerpt = ExcerptOffset::new(
1904                    diff_change_range
1905                        .start
1906                        .saturating_sub(excerpt_buffer_range.start),
1907                );
1908                let diff_change_end_in_excerpt = ExcerptOffset::new(
1909                    diff_change_range
1910                        .end
1911                        .saturating_sub(excerpt_buffer_range.start),
1912                );
1913                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
1914                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
1915                excerpt_edits.push(Edit {
1916                    old: edit_start..edit_end,
1917                    new: edit_start..edit_end,
1918                });
1919            }
1920        }
1921
1922        let edits = Self::sync_diff_transforms(
1923            &mut snapshot,
1924            excerpt_edits,
1925            DiffChangeKind::DiffUpdated {
1926                base_changed: base_text_changed,
1927            },
1928        );
1929        if !edits.is_empty() {
1930            self.subscriptions.publish(edits);
1931        }
1932        cx.emit(Event::Edited {
1933            edited_buffer: None,
1934        });
1935    }
1936
1937    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
1938        self.buffers
1939            .values()
1940            .map(|state| state.buffer.clone())
1941            .collect()
1942    }
1943
1944    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
1945        self.buffers.keys().copied().collect()
1946    }
1947
1948    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
1949        self.buffers
1950            .get(&buffer_id)
1951            .map(|state| state.buffer.clone())
1952    }
1953
1954    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
1955        self.point_to_buffer_offset(point, cx)
1956            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
1957    }
1958
1959    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
1960        let buffer_id = self
1961            .snapshot
1962            .borrow()
1963            .excerpts
1964            .first()
1965            .map(|excerpt| excerpt.buffer.remote_id());
1966        buffer_id
1967            .and_then(|buffer_id| self.buffer(buffer_id))
1968            .map(|buffer| {
1969                let buffer = buffer.read(cx);
1970                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
1971            })
1972            .unwrap_or_else(move || self.language_settings_at(0, cx))
1973    }
1974
1975    pub fn language_settings_at<'a, T: ToOffset>(
1976        &'a self,
1977        point: T,
1978        cx: &'a App,
1979    ) -> Cow<'a, LanguageSettings> {
1980        let mut language = None;
1981        let mut file = None;
1982        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
1983            let buffer = buffer.read(cx);
1984            language = buffer.language_at(offset);
1985            file = buffer.file();
1986        }
1987        language_settings(language.map(|l| l.name()), file, cx)
1988    }
1989
1990    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
1991        self.buffers.values().for_each(|state| f(&state.buffer))
1992    }
1993
1994    pub fn explicit_title(&self) -> Option<&str> {
1995        self.title.as_deref()
1996    }
1997
1998    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
1999        if let Some(title) = self.title.as_ref() {
2000            return title.into();
2001        }
2002
2003        if let Some(buffer) = self.as_singleton() {
2004            let buffer = buffer.read(cx);
2005
2006            if let Some(file) = buffer.file() {
2007                return file.file_name(cx).into();
2008            }
2009
2010            if let Some(title) = self.buffer_content_title(buffer) {
2011                return title;
2012            }
2013        };
2014
2015        "untitled".into()
2016    }
2017
2018    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2019        let mut is_leading_whitespace = true;
2020        let mut count = 0;
2021        let mut prev_was_space = false;
2022        let mut title = String::new();
2023
2024        for ch in buffer.snapshot().chars() {
2025            if is_leading_whitespace && ch.is_whitespace() {
2026                continue;
2027            }
2028
2029            is_leading_whitespace = false;
2030
2031            if ch == '\n' || count >= 40 {
2032                break;
2033            }
2034
2035            if ch.is_whitespace() {
2036                if !prev_was_space {
2037                    title.push(' ');
2038                    count += 1;
2039                    prev_was_space = true;
2040                }
2041            } else {
2042                title.push(ch);
2043                count += 1;
2044                prev_was_space = false;
2045            }
2046        }
2047
2048        let title = title.trim_end().to_string();
2049
2050        if title.is_empty() {
2051            return None;
2052        }
2053
2054        Some(title.into())
2055    }
2056
2057    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2058        self.title = Some(title);
2059        cx.notify();
2060    }
2061
2062    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2063    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2064        for buffer_state in self.buffers.values() {
2065            buffer_state
2066                .buffer
2067                .update(cx, |buffer, _cx| buffer.refresh_preview());
2068        }
2069    }
2070
2071    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2072    pub fn preserve_preview(&self, cx: &App) -> bool {
2073        self.buffers
2074            .values()
2075            .all(|state| state.buffer.read(cx).preserve_preview())
2076    }
2077
2078    #[cfg(any(test, feature = "test-support"))]
2079    pub fn is_parsing(&self, cx: &App) -> bool {
2080        self.as_singleton().unwrap().read(cx).is_parsing()
2081    }
2082
2083    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2084        let buffer_id = diff.read(cx).buffer_id;
2085        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2086        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2087    }
2088
2089    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2090        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2091    }
2092
2093    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2094        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2095    }
2096
2097    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2098        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2099    }
2100
2101    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2102        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2103        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2104    }
2105
2106    pub fn all_diff_hunks_expanded(&self) -> bool {
2107        self.snapshot.borrow().all_diff_hunks_expanded
2108    }
2109
2110    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2111        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2112        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2113    }
2114
2115    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2116        self.read(cx)
2117            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2118            .nth(1)
2119            .is_some()
2120    }
2121
2122    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2123        let snapshot = self.read(cx);
2124        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2125        let offset_range = range.to_offset(&snapshot);
2126        cursor.seek(&offset_range.start, Bias::Left);
2127        while let Some(item) = cursor.item() {
2128            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2129                break;
2130            }
2131            if item.hunk_info().is_some() {
2132                return true;
2133            }
2134            cursor.next();
2135        }
2136        false
2137    }
2138
2139    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2140        let snapshot = self.read(cx);
2141        let mut cursor = snapshot.diff_transforms.cursor::<usize>(());
2142        for range in ranges {
2143            let range = range.to_point(&snapshot);
2144            let start = snapshot.point_to_offset(MultiBufferPoint::new(range.start.row(), 0));
2145            let end = snapshot.point_to_offset(MultiBufferPoint::new(range.end.row() + 1, 0));
2146            let start = start.saturating_sub(1);
2147            let end = snapshot.len().min(end + 1);
2148            cursor.seek(&start, Bias::Right);
2149            while let Some(item) = cursor.item() {
2150                if *cursor.start() >= end {
2151                    break;
2152                }
2153                if item.hunk_info().is_some() {
2154                    return true;
2155                }
2156                cursor.next();
2157            }
2158        }
2159        false
2160    }
2161
2162    pub fn expand_or_collapse_diff_hunks_inner(
2163        &mut self,
2164        ranges: impl IntoIterator<Item = (Range<MultiBufferPoint>, ExcerptId)>,
2165        expand: bool,
2166        cx: &mut Context<Self>,
2167    ) {
2168        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2169            return;
2170        }
2171        self.sync_mut(cx);
2172        let mut snapshot = self.snapshot.get_mut();
2173        let mut excerpt_edits = Vec::new();
2174        let mut last_hunk_row = None;
2175        for (range, end_excerpt_id) in ranges {
2176            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2177                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2178                    continue;
2179                }
2180                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2181                    continue;
2182                }
2183                let start = Anchor::in_buffer(
2184                    diff_hunk.excerpt_id,
2185                    diff_hunk.buffer_id,
2186                    diff_hunk.buffer_range.start,
2187                );
2188                let end = Anchor::in_buffer(
2189                    diff_hunk.excerpt_id,
2190                    diff_hunk.buffer_id,
2191                    diff_hunk.buffer_range.end,
2192                );
2193                let start = snapshot.excerpt_offset_for_anchor(&start);
2194                let end = snapshot.excerpt_offset_for_anchor(&end);
2195                last_hunk_row = Some(diff_hunk.row_range.start);
2196                excerpt_edits.push(text::Edit {
2197                    old: start..end,
2198                    new: start..end,
2199                });
2200            }
2201        }
2202
2203        let edits = Self::sync_diff_transforms(
2204            &mut snapshot,
2205            excerpt_edits,
2206            DiffChangeKind::ExpandOrCollapseHunks { expand },
2207        );
2208        if !edits.is_empty() {
2209            self.subscriptions.publish(edits);
2210        }
2211        cx.emit(Event::DiffHunksToggled);
2212        cx.emit(Event::Edited {
2213            edited_buffer: None,
2214        });
2215    }
2216
2217    pub fn expand_or_collapse_diff_hunks(
2218        &mut self,
2219        ranges: Vec<Range<Anchor>>,
2220        expand: bool,
2221        cx: &mut Context<Self>,
2222    ) {
2223        let snapshot = self.snapshot.borrow().clone();
2224        let ranges = ranges.iter().map(move |range| {
2225            let end_excerpt_id = range.end.excerpt_id;
2226            let range = range.to_point(&snapshot);
2227            let mut peek_end = range.end;
2228            if range.end.row() < snapshot.max_row() {
2229                peek_end = MultiBufferPoint::new(range.end.row() + 1, 0);
2230            };
2231            (range.start..peek_end, end_excerpt_id)
2232        });
2233        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2234    }
2235
2236    pub fn resize_excerpt(
2237        &mut self,
2238        id: ExcerptId,
2239        range: Range<text::Anchor>,
2240        cx: &mut Context<Self>,
2241    ) {
2242        self.sync_mut(cx);
2243
2244        let mut snapshot = self.snapshot.get_mut();
2245        let locator = snapshot.excerpt_locator_for_id(id);
2246        let mut new_excerpts = SumTree::default();
2247        let mut cursor = snapshot
2248            .excerpts
2249            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2250        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2251
2252        let prefix = cursor.slice(&Some(locator), Bias::Left);
2253        new_excerpts.append(prefix, ());
2254
2255        let mut excerpt = cursor.item().unwrap().clone();
2256        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2257
2258        excerpt.range.context.start = range.start;
2259        excerpt.range.context.end = range.end;
2260        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2261
2262        excerpt.text_summary = excerpt
2263            .buffer
2264            .text_summary_for_range(excerpt.range.context.clone());
2265
2266        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2267        let old_start_offset = cursor.start().1;
2268        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2269        let edit = Edit {
2270            old: old_start_offset..old_start_offset + old_text_len,
2271            new: new_start_offset..new_start_offset + new_text_len,
2272        };
2273
2274        if let Some(last_edit) = edits.last_mut() {
2275            if last_edit.old.end == edit.old.start {
2276                last_edit.old.end = edit.old.end;
2277                last_edit.new.end = edit.new.end;
2278            } else {
2279                edits.push(edit);
2280            }
2281        } else {
2282            edits.push(edit);
2283        }
2284
2285        new_excerpts.push(excerpt, ());
2286
2287        cursor.next();
2288
2289        new_excerpts.append(cursor.suffix(), ());
2290
2291        drop(cursor);
2292        snapshot.excerpts = new_excerpts;
2293
2294        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2295        if !edits.is_empty() {
2296            self.subscriptions.publish(edits);
2297        }
2298        cx.emit(Event::Edited {
2299            edited_buffer: None,
2300        });
2301        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2302        cx.notify();
2303    }
2304
2305    pub fn expand_excerpts(
2306        &mut self,
2307        ids: impl IntoIterator<Item = ExcerptId>,
2308        line_count: u32,
2309        direction: ExpandExcerptDirection,
2310        cx: &mut Context<Self>,
2311    ) {
2312        if line_count == 0 {
2313            return;
2314        }
2315        self.sync_mut(cx);
2316        if !self.excerpts_by_path.is_empty() {
2317            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2318            return;
2319        }
2320        let mut snapshot = self.snapshot.get_mut();
2321
2322        let ids = ids.into_iter().collect::<Vec<_>>();
2323        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2324        let mut new_excerpts = SumTree::default();
2325        let mut cursor = snapshot
2326            .excerpts
2327            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2328        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2329
2330        for locator in &locators {
2331            let prefix = cursor.slice(&Some(locator), Bias::Left);
2332            new_excerpts.append(prefix, ());
2333
2334            let mut excerpt = cursor.item().unwrap().clone();
2335            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2336
2337            let up_line_count = if direction.should_expand_up() {
2338                line_count
2339            } else {
2340                0
2341            };
2342
2343            let start_row = excerpt
2344                .range
2345                .context
2346                .start
2347                .to_point(&excerpt.buffer)
2348                .row
2349                .saturating_sub(up_line_count);
2350            let start_point = Point::new(start_row, 0);
2351            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2352
2353            let down_line_count = if direction.should_expand_down() {
2354                line_count
2355            } else {
2356                0
2357            };
2358
2359            let mut end_point = excerpt.buffer.clip_point(
2360                excerpt.range.context.end.to_point(&excerpt.buffer)
2361                    + Point::new(down_line_count, 0),
2362                Bias::Left,
2363            );
2364            end_point.column = excerpt.buffer.line_len(end_point.row);
2365            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2366            excerpt.max_buffer_row = end_point.row;
2367
2368            excerpt.text_summary = excerpt
2369                .buffer
2370                .text_summary_for_range(excerpt.range.context.clone());
2371
2372            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2373            let old_start_offset = cursor.start().1;
2374            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2375            let edit = Edit {
2376                old: old_start_offset..old_start_offset + old_text_len,
2377                new: new_start_offset..new_start_offset + new_text_len,
2378            };
2379
2380            if let Some(last_edit) = edits.last_mut() {
2381                if last_edit.old.end == edit.old.start {
2382                    last_edit.old.end = edit.old.end;
2383                    last_edit.new.end = edit.new.end;
2384                } else {
2385                    edits.push(edit);
2386                }
2387            } else {
2388                edits.push(edit);
2389            }
2390
2391            new_excerpts.push(excerpt, ());
2392
2393            cursor.next();
2394        }
2395
2396        new_excerpts.append(cursor.suffix(), ());
2397
2398        drop(cursor);
2399        snapshot.excerpts = new_excerpts;
2400
2401        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2402        if !edits.is_empty() {
2403            self.subscriptions.publish(edits);
2404        }
2405        cx.emit(Event::Edited {
2406            edited_buffer: None,
2407        });
2408        cx.emit(Event::ExcerptsExpanded { ids });
2409        cx.notify();
2410    }
2411
2412    fn sync(&self, cx: &App) {
2413        let changed = self.buffer_changed_since_sync.replace(false);
2414        if !changed {
2415            return;
2416        }
2417        let edits = Self::sync_(
2418            &mut self.snapshot.borrow_mut(),
2419            &self.buffers,
2420            &self.diffs,
2421            cx,
2422        );
2423        if !edits.is_empty() {
2424            self.subscriptions.publish(edits);
2425        }
2426    }
2427
2428    fn sync_mut(&mut self, cx: &App) {
2429        let changed = self.buffer_changed_since_sync.replace(false);
2430        if !changed {
2431            return;
2432        }
2433        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2434
2435        if !edits.is_empty() {
2436            self.subscriptions.publish(edits);
2437        }
2438    }
2439
2440    fn sync_(
2441        snapshot: &mut MultiBufferSnapshot,
2442        buffers: &HashMap<BufferId, BufferState>,
2443        diffs: &HashMap<BufferId, DiffState>,
2444        cx: &App,
2445    ) -> Vec<Edit<usize>> {
2446        let MultiBufferSnapshot {
2447            excerpts,
2448            diffs: buffer_diff,
2449            diff_transforms: _,
2450            non_text_state_update_count,
2451            edit_count,
2452            is_dirty,
2453            has_deleted_file,
2454            has_conflict,
2455            singleton: _,
2456            excerpt_ids: _,
2457            replaced_excerpts: _,
2458            trailing_excerpt_update_count: _,
2459            all_diff_hunks_expanded: _,
2460            show_headers: _,
2461        } = snapshot;
2462        *is_dirty = false;
2463        *has_deleted_file = false;
2464        *has_conflict = false;
2465
2466        let mut excerpts_to_edit = Vec::new();
2467        let mut non_text_state_updated = false;
2468        let mut edited = false;
2469        for buffer_state in buffers.values() {
2470            let buffer = buffer_state.buffer.read(cx);
2471            let version = buffer.version();
2472            let non_text_state_update_count = buffer.non_text_state_update_count();
2473
2474            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2475            let buffer_non_text_state_updated =
2476                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2477            if buffer_edited || buffer_non_text_state_updated {
2478                *buffer_state.last_version.borrow_mut() = version;
2479                buffer_state
2480                    .last_non_text_state_update_count
2481                    .set(non_text_state_update_count);
2482                excerpts_to_edit.extend(
2483                    buffer_state
2484                        .excerpts
2485                        .iter()
2486                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2487                );
2488            }
2489
2490            edited |= buffer_edited;
2491            non_text_state_updated |= buffer_non_text_state_updated;
2492            *is_dirty |= buffer.is_dirty();
2493            *has_deleted_file |= buffer
2494                .file()
2495                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
2496            *has_conflict |= buffer.has_conflict();
2497        }
2498        if edited {
2499            *edit_count += 1;
2500        }
2501        if non_text_state_updated {
2502            *non_text_state_update_count += 1;
2503        }
2504
2505        for (id, diff) in diffs.iter() {
2506            if buffer_diff.get(id).is_none() {
2507                buffer_diff.insert(*id, diff.diff.read(cx).snapshot(cx));
2508            }
2509        }
2510
2511        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2512
2513        let mut edits = Vec::new();
2514        let mut new_excerpts = SumTree::default();
2515        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2516
2517        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2518            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2519            let old_excerpt = cursor.item().unwrap();
2520            let buffer = buffer.read(cx);
2521            let buffer_id = buffer.remote_id();
2522
2523            let mut new_excerpt;
2524            if buffer_edited {
2525                edits.extend(
2526                    buffer
2527                        .edits_since_in_range::<usize>(
2528                            old_excerpt.buffer.version(),
2529                            old_excerpt.range.context.clone(),
2530                        )
2531                        .map(|edit| {
2532                            let excerpt_old_start = cursor.start().1;
2533                            let excerpt_new_start =
2534                                ExcerptOffset::new(new_excerpts.summary().text.len);
2535                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2536                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2537                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2538                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2539                            Edit {
2540                                old: old_start..old_end,
2541                                new: new_start..new_end,
2542                            }
2543                        }),
2544                );
2545
2546                new_excerpt = Excerpt::new(
2547                    old_excerpt.id,
2548                    locator.clone(),
2549                    buffer_id,
2550                    buffer.snapshot(),
2551                    old_excerpt.range.clone(),
2552                    old_excerpt.has_trailing_newline,
2553                );
2554            } else {
2555                new_excerpt = old_excerpt.clone();
2556                new_excerpt.buffer = buffer.snapshot();
2557            }
2558
2559            new_excerpts.push(new_excerpt, ());
2560            cursor.next();
2561        }
2562        new_excerpts.append(cursor.suffix(), ());
2563
2564        drop(cursor);
2565        *excerpts = new_excerpts;
2566        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2567    }
2568
2569    fn sync_diff_transforms(
2570        snapshot: &mut MultiBufferSnapshot,
2571        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2572        change_kind: DiffChangeKind,
2573    ) -> Vec<Edit<usize>> {
2574        if excerpt_edits.is_empty() {
2575            return vec![];
2576        }
2577
2578        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2579        let mut old_diff_transforms = snapshot
2580            .diff_transforms
2581            .cursor::<Dimensions<ExcerptOffset, usize>>(());
2582        let mut new_diff_transforms = SumTree::default();
2583        let mut old_expanded_hunks = HashSet::default();
2584        let mut output_edits = Vec::new();
2585        let mut output_delta = 0_isize;
2586        let mut at_transform_boundary = true;
2587        let mut end_of_current_insert = None;
2588
2589        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2590        while let Some(edit) = excerpt_edits.next() {
2591            excerpts.seek_forward(&edit.new.start, Bias::Right);
2592            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2593                excerpts.prev();
2594            }
2595
2596            // Keep any transforms that are before the edit.
2597            if at_transform_boundary {
2598                at_transform_boundary = false;
2599                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2600                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2601                if let Some(transform) = old_diff_transforms.item()
2602                    && old_diff_transforms.end().0 == edit.old.start
2603                    && old_diff_transforms.start().0 < edit.old.start
2604                {
2605                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2606                    old_diff_transforms.next();
2607                }
2608            }
2609
2610            // Compute the start of the edit in output coordinates.
2611            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2612            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2613            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
2614
2615            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2616                &edit,
2617                &mut excerpts,
2618                &mut old_diff_transforms,
2619                &mut new_diff_transforms,
2620                &mut end_of_current_insert,
2621                &mut old_expanded_hunks,
2622                snapshot,
2623                change_kind,
2624            );
2625
2626            // Compute the end of the edit in output coordinates.
2627            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2628            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2629            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2630            let edit_new_end =
2631                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2632            let output_edit = Edit {
2633                old: edit_old_start..edit_old_end,
2634                new: edit_new_start..edit_new_end,
2635            };
2636
2637            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2638            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2639            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2640                output_edits.push(output_edit);
2641            }
2642
2643            // If this is the last edit that intersects the current diff transform,
2644            // then recreate the content up to the end of this transform, to prepare
2645            // for reusing additional slices of the old transforms.
2646            if excerpt_edits
2647                .peek()
2648                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2649            {
2650                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2651                    && match old_diff_transforms.item() {
2652                        Some(DiffTransform::BufferContent {
2653                            inserted_hunk_info: Some(hunk),
2654                            ..
2655                        }) => excerpts.item().is_some_and(|excerpt| {
2656                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2657                        }),
2658                        _ => true,
2659                    };
2660
2661                let mut excerpt_offset = edit.new.end;
2662                if !keep_next_old_transform {
2663                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2664                    old_diff_transforms.next();
2665                }
2666
2667                old_expanded_hunks.clear();
2668                Self::push_buffer_content_transform(
2669                    snapshot,
2670                    &mut new_diff_transforms,
2671                    excerpt_offset,
2672                    end_of_current_insert,
2673                );
2674                at_transform_boundary = true;
2675            }
2676        }
2677
2678        // Keep any transforms that are after the last edit.
2679        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2680
2681        // Ensure there's always at least one buffer content transform.
2682        if new_diff_transforms.is_empty() {
2683            new_diff_transforms.push(
2684                DiffTransform::BufferContent {
2685                    summary: Default::default(),
2686                    inserted_hunk_info: None,
2687                },
2688                (),
2689            );
2690        }
2691
2692        drop(old_diff_transforms);
2693        drop(excerpts);
2694        snapshot.diff_transforms = new_diff_transforms;
2695        snapshot.edit_count += 1;
2696
2697        #[cfg(any(test, feature = "test-support"))]
2698        snapshot.check_invariants();
2699        output_edits
2700    }
2701
2702    fn recompute_diff_transforms_for_edit(
2703        edit: &Edit<TypedOffset<Excerpt>>,
2704        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
2705        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
2706        new_diff_transforms: &mut SumTree<DiffTransform>,
2707        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
2708        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2709        snapshot: &MultiBufferSnapshot,
2710        change_kind: DiffChangeKind,
2711    ) -> bool {
2712        log::trace!(
2713            "recomputing diff transform for edit {:?} => {:?}",
2714            edit.old.start.value..edit.old.end.value,
2715            edit.new.start.value..edit.new.end.value
2716        );
2717
2718        // Record which hunks were previously expanded.
2719        while let Some(item) = old_diff_transforms.item() {
2720            if let Some(hunk_info) = item.hunk_info() {
2721                log::trace!(
2722                    "previously expanded hunk at {}",
2723                    old_diff_transforms.start().0
2724                );
2725                old_expanded_hunks.insert(hunk_info);
2726            }
2727            if old_diff_transforms.end().0 > edit.old.end {
2728                break;
2729            }
2730            old_diff_transforms.next();
2731        }
2732
2733        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2734        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2735        if old_expanded_hunks.is_empty()
2736            && change_kind == DiffChangeKind::BufferEdited
2737            && !all_diff_hunks_expanded
2738        {
2739            return false;
2740        }
2741
2742        // Visit each excerpt that intersects the edit.
2743        let mut did_expand_hunks = false;
2744        while let Some(excerpt) = excerpts.item() {
2745            // Recompute the expanded hunks in the portion of the excerpt that
2746            // intersects the edit.
2747            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2748                let buffer = &excerpt.buffer;
2749                let excerpt_start = *excerpts.start();
2750                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
2751                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2752                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2753                let edit_buffer_start =
2754                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
2755                let edit_buffer_end =
2756                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
2757                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2758                let edit_anchor_range =
2759                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
2760
2761                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2762                    if hunk.is_created_file() && !all_diff_hunks_expanded {
2763                        continue;
2764                    }
2765
2766                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2767                    if hunk_buffer_range.start < excerpt_buffer_start {
2768                        log::trace!("skipping hunk that starts before excerpt");
2769                        continue;
2770                    }
2771
2772                    let hunk_info = DiffTransformHunkInfo {
2773                        excerpt_id: excerpt.id,
2774                        hunk_start_anchor: hunk.buffer_range.start,
2775                        hunk_secondary_status: hunk.secondary_status,
2776                    };
2777
2778                    let hunk_excerpt_start = excerpt_start
2779                        + ExcerptOffset::new(
2780                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
2781                        );
2782                    let hunk_excerpt_end = excerpt_end.min(
2783                        excerpt_start
2784                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
2785                    );
2786
2787                    Self::push_buffer_content_transform(
2788                        snapshot,
2789                        new_diff_transforms,
2790                        hunk_excerpt_start,
2791                        *end_of_current_insert,
2792                    );
2793
2794                    // For every existing hunk, determine if it was previously expanded
2795                    // and if it should currently be expanded.
2796                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2797                    let should_expand_hunk = match &change_kind {
2798                        DiffChangeKind::DiffUpdated { base_changed: true } => {
2799                            was_previously_expanded || all_diff_hunks_expanded
2800                        }
2801                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2802                            let intersects = hunk_buffer_range.is_empty()
2803                                || hunk_buffer_range.end > edit_buffer_start;
2804                            if *expand {
2805                                intersects || was_previously_expanded || all_diff_hunks_expanded
2806                            } else {
2807                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
2808                            }
2809                        }
2810                        _ => was_previously_expanded || all_diff_hunks_expanded,
2811                    };
2812
2813                    if should_expand_hunk {
2814                        did_expand_hunks = true;
2815                        log::trace!(
2816                            "expanding hunk {:?}, excerpt:{:?}",
2817                            hunk_excerpt_start.value..hunk_excerpt_end.value,
2818                            excerpt.id
2819                        );
2820
2821                        if !hunk.diff_base_byte_range.is_empty()
2822                            && hunk_buffer_range.start >= edit_buffer_start
2823                            && hunk_buffer_range.start <= excerpt_buffer_end
2824                        {
2825                            let base_text = diff.base_text();
2826                            let mut text_cursor =
2827                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2828                            let mut base_text_summary =
2829                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
2830
2831                            let mut has_trailing_newline = false;
2832                            if base_text_summary.last_line_chars > 0 {
2833                                base_text_summary += TextSummary::newline();
2834                                has_trailing_newline = true;
2835                            }
2836
2837                            new_diff_transforms.push(
2838                                DiffTransform::DeletedHunk {
2839                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
2840                                    summary: base_text_summary,
2841                                    buffer_id: excerpt.buffer_id,
2842                                    hunk_info,
2843                                    has_trailing_newline,
2844                                },
2845                                (),
2846                            );
2847                        }
2848
2849                        if !hunk_buffer_range.is_empty() {
2850                            *end_of_current_insert =
2851                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2852                        }
2853                    }
2854                }
2855            }
2856
2857            if excerpts.end() <= edit.new.end {
2858                excerpts.next();
2859            } else {
2860                break;
2861            }
2862        }
2863
2864        did_expand_hunks || !old_expanded_hunks.is_empty()
2865    }
2866
2867    fn append_diff_transforms(
2868        new_transforms: &mut SumTree<DiffTransform>,
2869        subtree: SumTree<DiffTransform>,
2870    ) {
2871        if let Some(DiffTransform::BufferContent {
2872            inserted_hunk_info,
2873            summary,
2874        }) = subtree.first()
2875            && Self::extend_last_buffer_content_transform(
2876                new_transforms,
2877                *inserted_hunk_info,
2878                *summary,
2879            )
2880        {
2881            let mut cursor = subtree.cursor::<()>(());
2882            cursor.next();
2883            cursor.next();
2884            new_transforms.append(cursor.suffix(), ());
2885            return;
2886        }
2887        new_transforms.append(subtree, ());
2888    }
2889
2890    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
2891        if let DiffTransform::BufferContent {
2892            inserted_hunk_info: inserted_hunk_anchor,
2893            summary,
2894        } = transform
2895            && Self::extend_last_buffer_content_transform(
2896                new_transforms,
2897                inserted_hunk_anchor,
2898                summary,
2899            )
2900        {
2901            return;
2902        }
2903        new_transforms.push(transform, ());
2904    }
2905
2906    fn push_buffer_content_transform(
2907        old_snapshot: &MultiBufferSnapshot,
2908        new_transforms: &mut SumTree<DiffTransform>,
2909        end_offset: ExcerptOffset,
2910        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2911    ) {
2912        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
2913            (end_offset.min(insertion_end_offset), Some(hunk_info))
2914        });
2915        let unchanged_region = [(end_offset, None)];
2916
2917        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
2918        {
2919            let start_offset = new_transforms.summary().excerpt_len();
2920            if end_offset <= start_offset {
2921                continue;
2922            }
2923            let summary_to_add = old_snapshot
2924                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
2925
2926            if !Self::extend_last_buffer_content_transform(
2927                new_transforms,
2928                inserted_hunk_info,
2929                summary_to_add,
2930            ) {
2931                new_transforms.push(
2932                    DiffTransform::BufferContent {
2933                        summary: summary_to_add,
2934                        inserted_hunk_info,
2935                    },
2936                    (),
2937                )
2938            }
2939        }
2940    }
2941
2942    fn extend_last_buffer_content_transform(
2943        new_transforms: &mut SumTree<DiffTransform>,
2944        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
2945        summary_to_add: TextSummary,
2946    ) -> bool {
2947        let mut did_extend = false;
2948        new_transforms.update_last(
2949            |last_transform| {
2950                if let DiffTransform::BufferContent {
2951                    summary,
2952                    inserted_hunk_info: inserted_hunk_anchor,
2953                } = last_transform
2954                    && *inserted_hunk_anchor == new_inserted_hunk_info
2955                {
2956                    *summary += summary_to_add;
2957                    did_extend = true;
2958                }
2959            },
2960            (),
2961        );
2962        did_extend
2963    }
2964}
2965
2966fn build_excerpt_ranges(
2967    ranges: impl IntoIterator<Item = Range<Point>>,
2968    context_line_count: u32,
2969    buffer_snapshot: &BufferSnapshot,
2970) -> Vec<ExcerptRange<Point>> {
2971    ranges
2972        .into_iter()
2973        .map(|range| {
2974            let start_row = range.start.row.saturating_sub(context_line_count);
2975            let start = Point::new(start_row, 0);
2976            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
2977            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
2978            ExcerptRange {
2979                context: start..end,
2980                primary: range,
2981            }
2982        })
2983        .collect()
2984}
2985
2986#[cfg(any(test, feature = "test-support"))]
2987impl MultiBuffer {
2988    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
2989        let buffer = cx.new(|cx| Buffer::local(text, cx));
2990        cx.new(|cx| Self::singleton(buffer, cx))
2991    }
2992
2993    pub fn build_multi<const COUNT: usize>(
2994        excerpts: [(&str, Vec<Range<Point>>); COUNT],
2995        cx: &mut gpui::App,
2996    ) -> Entity<Self> {
2997        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
2998        for (text, ranges) in excerpts {
2999            let buffer = cx.new(|cx| Buffer::local(text, cx));
3000            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3001            multi.update(cx, |multi, cx| {
3002                multi.push_excerpts(buffer, excerpt_ranges, cx)
3003            });
3004        }
3005
3006        multi
3007    }
3008
3009    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3010        cx.new(|cx| Self::singleton(buffer, cx))
3011    }
3012
3013    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3014        cx.new(|cx| {
3015            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3016            let mutation_count = rng.random_range(1..=5);
3017            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3018            multibuffer
3019        })
3020    }
3021
3022    pub fn randomly_edit(
3023        &mut self,
3024        rng: &mut impl rand::Rng,
3025        edit_count: usize,
3026        cx: &mut Context<Self>,
3027    ) {
3028        use util::RandomCharIter;
3029
3030        let snapshot = self.read(cx);
3031        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3032        let mut last_end = None;
3033        for _ in 0..edit_count {
3034            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3035                break;
3036            }
3037
3038            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3039            let end =
3040                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3041            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3042            last_end = Some(end);
3043
3044            let mut range = start..end;
3045            if rng.random_bool(0.2) {
3046                mem::swap(&mut range.start, &mut range.end);
3047            }
3048
3049            let new_text_len = rng.random_range(0..10);
3050            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3051
3052            edits.push((range, new_text.into()));
3053        }
3054        log::info!("mutating multi-buffer with {:?}", edits);
3055        drop(snapshot);
3056
3057        self.edit(edits, None, cx);
3058    }
3059
3060    pub fn randomly_edit_excerpts(
3061        &mut self,
3062        rng: &mut impl rand::Rng,
3063        mutation_count: usize,
3064        cx: &mut Context<Self>,
3065    ) {
3066        use rand::prelude::*;
3067        use std::env;
3068        use util::RandomCharIter;
3069
3070        let max_excerpts = env::var("MAX_EXCERPTS")
3071            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3072            .unwrap_or(5);
3073
3074        let mut buffers = Vec::new();
3075        for _ in 0..mutation_count {
3076            if rng.random_bool(0.05) {
3077                log::info!("Clearing multi-buffer");
3078                self.clear(cx);
3079                continue;
3080            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3081                let ids = self.excerpt_ids();
3082                let mut excerpts = HashSet::default();
3083                for _ in 0..rng.random_range(0..ids.len()) {
3084                    excerpts.extend(ids.choose(rng).copied());
3085                }
3086
3087                let line_count = rng.random_range(0..5);
3088
3089                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3090
3091                self.expand_excerpts(
3092                    excerpts.iter().cloned(),
3093                    line_count,
3094                    ExpandExcerptDirection::UpAndDown,
3095                    cx,
3096                );
3097                continue;
3098            }
3099
3100            let excerpt_ids = self.excerpt_ids();
3101            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3102                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3103                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3104                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3105                    let buffer = buffers.last().unwrap().read(cx);
3106                    log::info!(
3107                        "Creating new buffer {} with text: {:?}",
3108                        buffer.remote_id(),
3109                        buffer.text()
3110                    );
3111                    buffers.last().unwrap().clone()
3112                } else {
3113                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3114                };
3115
3116                let buffer = buffer_handle.read(cx);
3117                let buffer_text = buffer.text();
3118                let ranges = (0..rng.random_range(0..5))
3119                    .map(|_| {
3120                        let end_ix =
3121                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3122                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3123                        ExcerptRange::new(start_ix..end_ix)
3124                    })
3125                    .collect::<Vec<_>>();
3126                log::info!(
3127                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3128                    buffer_handle.read(cx).remote_id(),
3129                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3130                    ranges
3131                        .iter()
3132                        .map(|r| &buffer_text[r.context.clone()])
3133                        .collect::<Vec<_>>()
3134                );
3135
3136                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3137                log::info!("Inserted with ids: {:?}", excerpt_id);
3138            } else {
3139                let remove_count = rng.random_range(1..=excerpt_ids.len());
3140                let mut excerpts_to_remove = excerpt_ids
3141                    .choose_multiple(rng, remove_count)
3142                    .cloned()
3143                    .collect::<Vec<_>>();
3144                let snapshot = self.snapshot.borrow();
3145                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3146                drop(snapshot);
3147                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3148                self.remove_excerpts(excerpts_to_remove, cx);
3149            }
3150        }
3151    }
3152
3153    pub fn randomly_mutate(
3154        &mut self,
3155        rng: &mut impl rand::Rng,
3156        mutation_count: usize,
3157        cx: &mut Context<Self>,
3158    ) {
3159        use rand::prelude::*;
3160
3161        if rng.random_bool(0.7) || self.singleton {
3162            let buffer = self
3163                .buffers
3164                .values()
3165                .choose(rng)
3166                .map(|state| state.buffer.clone());
3167
3168            if let Some(buffer) = buffer {
3169                buffer.update(cx, |buffer, cx| {
3170                    if rng.random() {
3171                        buffer.randomly_edit(rng, mutation_count, cx);
3172                    } else {
3173                        buffer.randomly_undo_redo(rng, cx);
3174                    }
3175                });
3176            } else {
3177                self.randomly_edit(rng, mutation_count, cx);
3178            }
3179        } else {
3180            self.randomly_edit_excerpts(rng, mutation_count, cx);
3181        }
3182
3183        self.check_invariants(cx);
3184    }
3185
3186    fn check_invariants(&self, cx: &App) {
3187        self.read(cx).check_invariants();
3188    }
3189}
3190
3191impl EventEmitter<Event> for MultiBuffer {}
3192
3193impl MultiBufferSnapshot {
3194    pub fn text(&self) -> String {
3195        self.chunks(0..self.len(), false)
3196            .map(|chunk| chunk.text)
3197            .collect()
3198    }
3199
3200    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3201        self.reversed_chunks_in_range(0..position.to_offset(self))
3202            .flat_map(|c| c.chars().rev())
3203    }
3204
3205    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3206        let mut cursor = self.cursor::<usize, usize>();
3207        cursor.seek(&range.end);
3208        let current_chunks = cursor.region().as_ref().map(|region| {
3209            let start_overshoot = range.start.saturating_sub(region.range.start);
3210            let end_overshoot = range.end - region.range.start;
3211            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3212            let start = region.buffer_range.start + start_overshoot;
3213            region.buffer.reversed_chunks_in_range(start..end)
3214        });
3215        ReversedMultiBufferChunks {
3216            cursor,
3217            current_chunks,
3218            start: range.start,
3219            offset: range.end,
3220        }
3221    }
3222
3223    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3224        let offset = position.to_offset(self);
3225        self.text_for_range(offset..self.len())
3226            .flat_map(|chunk| chunk.chars())
3227    }
3228
3229    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3230        self.chunks(range, false).map(|chunk| chunk.text)
3231    }
3232
3233    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3234        self.text_for_range(
3235            MultiBufferPoint::new(row, 0)..MultiBufferPoint::new(row, self.line_len(row)),
3236        )
3237        .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3238    }
3239
3240    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3241    where
3242        T: ToOffset,
3243    {
3244        let position = position.to_offset(self);
3245        position == self.clip_offset(position, Bias::Left)
3246            && self
3247                .bytes_in_range(position..self.len())
3248                .flatten()
3249                .copied()
3250                .take(needle.len())
3251                .eq(needle.bytes())
3252    }
3253
3254    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3255        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3256    }
3257
3258    pub fn diff_hunks_in_range<T: ToPoint>(
3259        &self,
3260        range: Range<T>,
3261    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3262        let query_range = range.start.to_point(self)..range.end.to_point(self);
3263        self.lift_buffer_metadata::<Point, _, _, _>(
3264            query_range.clone(),
3265            move |buffer, buffer_range| {
3266                let diff = self.diffs.get(&buffer.remote_id())?;
3267                let buffer_start = buffer.anchor_before(buffer_range.start);
3268                let buffer_end = buffer.anchor_after(buffer_range.end);
3269                Some(
3270                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3271                        .filter_map(|hunk| {
3272                            if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3273                                return None;
3274                            }
3275                            Some((hunk.range.clone(), hunk))
3276                        }),
3277                )
3278            },
3279        )
3280        .filter_map(move |(range, _, hunk, excerpt)| {
3281            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3282            {
3283                return None;
3284            }
3285            let end_row = if range.end.column() == 0 {
3286                range.end.row()
3287            } else {
3288                range.end.row() + 1
3289            };
3290            Some(MultiBufferDiffHunk {
3291                row_range: range.start.row()..end_row,
3292                buffer_id: excerpt.buffer_id,
3293                excerpt_id: excerpt.id,
3294                buffer_range: hunk.buffer_range.clone(),
3295                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3296                secondary_status: hunk.secondary_status,
3297            })
3298        })
3299    }
3300
3301    pub fn excerpt_ids_for_range<T: ToOffset>(
3302        &self,
3303        range: Range<T>,
3304    ) -> impl Iterator<Item = ExcerptId> + '_ {
3305        let range = range.start.to_offset(self)..range.end.to_offset(self);
3306        let mut cursor = self.cursor::<usize, usize>();
3307        cursor.seek(&range.start);
3308        std::iter::from_fn(move || {
3309            let region = cursor.region()?;
3310            if region.range.start >= range.end {
3311                return None;
3312            }
3313            cursor.next_excerpt();
3314            Some(region.excerpt.id)
3315        })
3316    }
3317
3318    pub fn buffer_ids_for_range<T: ToOffset>(
3319        &self,
3320        range: Range<T>,
3321    ) -> impl Iterator<Item = BufferId> + '_ {
3322        let range = range.start.to_offset(self)..range.end.to_offset(self);
3323        let mut cursor = self.cursor::<usize, usize>();
3324        cursor.seek(&range.start);
3325        std::iter::from_fn(move || {
3326            let region = cursor.region()?;
3327            if region.range.start > range.end
3328                || region.range.start == range.end && region.range.start > range.start
3329            {
3330                return None;
3331            }
3332            cursor.next_excerpt();
3333            Some(region.excerpt.buffer_id)
3334        })
3335    }
3336
3337    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3338        &self,
3339        ranges: impl Iterator<Item = Range<T>>,
3340    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3341        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3342    }
3343
3344    pub fn range_to_buffer_ranges<T: ToOffset>(
3345        &self,
3346        range: Range<T>,
3347    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3348        let start = range.start.to_offset(self);
3349        let end = range.end.to_offset(self);
3350
3351        let mut cursor = self.cursor::<usize, usize>();
3352        cursor.seek(&start);
3353
3354        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3355        while let Some(region) = cursor.region() {
3356            if region.range.start > end {
3357                break;
3358            }
3359            if region.is_main_buffer {
3360                let start_overshoot = start.saturating_sub(region.range.start);
3361                let end_overshoot = end.saturating_sub(region.range.start);
3362                let start = region
3363                    .buffer_range
3364                    .end
3365                    .min(region.buffer_range.start + start_overshoot);
3366                let end = region
3367                    .buffer_range
3368                    .end
3369                    .min(region.buffer_range.start + end_overshoot);
3370                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3371                    *excerpt_id == region.excerpt.id && prev_range.end == start
3372                }) {
3373                    prev.1.end = end;
3374                } else {
3375                    result.push((region.buffer, start..end, region.excerpt.id));
3376                }
3377            }
3378            cursor.next();
3379        }
3380        result
3381    }
3382
3383    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3384        &self,
3385        range: Range<T>,
3386    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3387        let start = range.start.to_offset(self);
3388        let end = range.end.to_offset(self);
3389
3390        let mut cursor = self.cursor::<usize, usize>();
3391        cursor.seek(&start);
3392
3393        std::iter::from_fn(move || {
3394            let region = cursor.region()?;
3395            if region.range.start > end {
3396                return None;
3397            }
3398            let start_overshoot = start.saturating_sub(region.range.start);
3399            let end_overshoot = end.saturating_sub(region.range.start);
3400            let start = region
3401                .buffer_range
3402                .end
3403                .min(region.buffer_range.start + start_overshoot);
3404            let end = region
3405                .buffer_range
3406                .end
3407                .min(region.buffer_range.start + end_overshoot);
3408
3409            let region_excerpt_id = region.excerpt.id;
3410            let deleted_hunk_anchor = if region.is_main_buffer {
3411                None
3412            } else {
3413                Some(self.anchor_before(region.range.start))
3414            };
3415            let result = (
3416                region.buffer,
3417                start..end,
3418                region_excerpt_id,
3419                deleted_hunk_anchor,
3420            );
3421            cursor.next();
3422            Some(result)
3423        })
3424    }
3425
3426    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3427    /// coordinates.
3428    ///
3429    /// The given callback will be called for every excerpt intersecting the given range. It will
3430    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3431    /// The callback should return an iterator of metadata items from that buffer, each paired
3432    /// with a buffer range.
3433    ///
3434    /// The returned iterator yields each of these metadata items, paired with its range in
3435    /// multi-buffer coordinates.
3436    fn lift_buffer_metadata<'a, LBD, MBD, M, I>(
3437        &'a self,
3438        query_range: Range<MBD>,
3439        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<LBD>) -> Option<I>,
3440    ) -> impl Iterator<Item = (Range<MBD>, Range<LBD>, M, &'a Excerpt)> + 'a
3441    where
3442        LBD: LangBufferDimension,
3443        MBD: MultiBufferDimension<Distance = LBD::Distance> + 'a,
3444        I: Iterator<Item = (Range<LBD>, M)> + 'a,
3445    {
3446        let max_position = MBD::max_position(self);
3447        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3448        let mut cursor = self.cursor::<LBD, MBD>();
3449
3450        // Find the excerpt and buffer offset where the given range ends.
3451        cursor.seek(&query_range.end);
3452        let mut range_end = None;
3453        while let Some(region) = cursor.region() {
3454            if region.is_main_buffer {
3455                let mut buffer_end = region.buffer_range.start;
3456                let overshoot = if query_range.end > region.range.start {
3457                    query_range.end.distance_to(region.range.start)
3458                } else {
3459                    LBD::Distance::default()
3460                };
3461                buffer_end.add_distance(overshoot);
3462                range_end = Some((region.excerpt.id, buffer_end));
3463                break;
3464            }
3465            cursor.next();
3466        }
3467
3468        cursor.seek(&query_range.start);
3469
3470        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3471            && region.range.start > MBD::default()
3472        {
3473            cursor.prev()
3474        }
3475
3476        iter::from_fn(move || {
3477            loop {
3478                let excerpt = cursor.excerpt()?;
3479
3480                // If we have already retrieved metadata for this excerpt, continue to use it.
3481                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3482                    .as_mut()
3483                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3484                {
3485                    Some(metadata)
3486                }
3487                // Otherwise, compute the intersection of the input range with the excerpt's range,
3488                // and retrieve the metadata for the resulting range.
3489                else {
3490                    let region = cursor.region()?;
3491                    let mut buffer_start;
3492                    if region.is_main_buffer {
3493                        buffer_start = region.buffer_range.start;
3494                        if query_range.start > region.range.start {
3495                            let overshoot = query_range.start.distance_to(region.range.start);
3496                            buffer_start.add_distance(overshoot);
3497                        }
3498                        buffer_start = buffer_start.min(region.buffer_range.end);
3499                    } else {
3500                        buffer_start = cursor.main_buffer_position()?;
3501                    };
3502                    let mut buffer_end = excerpt.range.context.end.summary::<LBD>(&excerpt.buffer);
3503                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
3504                        && excerpt.id == end_excerpt_id
3505                    {
3506                        buffer_end = buffer_end.min(end_buffer_offset);
3507                    }
3508
3509                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
3510                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
3511                    })
3512                };
3513
3514                // Visit each metadata item.
3515                if let Some((metadata_buffer_range, metadata)) =
3516                    metadata_iter.and_then(Iterator::next)
3517                {
3518                    // Find the multibuffer regions that contain the start and end of
3519                    // the metadata item's range.
3520                    if metadata_buffer_range.start > LBD::default() {
3521                        while let Some(region) = cursor.region() {
3522                            if region.is_main_buffer
3523                                && (region.buffer_range.end >= metadata_buffer_range.start
3524                                    || cursor.is_at_end_of_excerpt())
3525                            {
3526                                break;
3527                            }
3528                            cursor.next();
3529                        }
3530                    }
3531                    let start_region = cursor.region()?;
3532                    while let Some(region) = cursor.region() {
3533                        if region.is_main_buffer
3534                            && (region.buffer_range.end > metadata_buffer_range.end
3535                                || cursor.is_at_end_of_excerpt())
3536                        {
3537                            break;
3538                        }
3539                        cursor.next();
3540                    }
3541                    let end_region = cursor.region();
3542
3543                    // Convert the metadata item's range into multibuffer coordinates.
3544                    let mut start_position = start_region.range.start;
3545                    let region_buffer_start = start_region.buffer_range.start;
3546                    if start_region.is_main_buffer
3547                        && metadata_buffer_range.start > region_buffer_start
3548                    {
3549                        start_position.add_distance(
3550                            metadata_buffer_range.start.distance_to(region_buffer_start),
3551                        );
3552                        start_position = start_position.min(start_region.range.end);
3553                    }
3554
3555                    let mut end_position = max_position;
3556                    if let Some(end_region) = &end_region {
3557                        end_position = end_region.range.start;
3558                        debug_assert!(end_region.is_main_buffer);
3559                        let region_buffer_start = end_region.buffer_range.start;
3560                        if metadata_buffer_range.end > region_buffer_start {
3561                            end_position.add_distance(
3562                                metadata_buffer_range.end.distance_to(region_buffer_start),
3563                            );
3564                        }
3565                        end_position = end_position.min(end_region.range.end);
3566                    }
3567
3568                    if start_position <= query_range.end && end_position >= query_range.start {
3569                        return Some((
3570                            start_position..end_position,
3571                            metadata_buffer_range,
3572                            metadata,
3573                            excerpt,
3574                        ));
3575                    }
3576                }
3577                // When there are no more metadata items for this excerpt, move to the next excerpt.
3578                else {
3579                    current_excerpt_metadata.take();
3580                    if let Some((end_excerpt_id, _)) = range_end
3581                        && excerpt.id == end_excerpt_id
3582                    {
3583                        return None;
3584                    }
3585                    cursor.next_excerpt();
3586                }
3587            }
3588        })
3589    }
3590
3591    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3592        let offset = position.to_offset(self);
3593
3594        let mut cursor =
3595            self.cursor::<usize, DimensionPair<usize, OutputDimension<MultiBufferPoint>>>();
3596        cursor.seek(&DimensionPair {
3597            key: offset,
3598            value: None,
3599        });
3600        cursor.seek_to_start_of_current_excerpt();
3601        let excerpt = cursor.excerpt()?;
3602
3603        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3604        let current_position = self
3605            .anchor_before(offset)
3606            .text_anchor
3607            .to_offset(&excerpt.buffer);
3608        let excerpt_end = excerpt
3609            .buffer
3610            .anchor_before(excerpt_end.min(current_position));
3611
3612        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3613            for hunk in diff.hunks_intersecting_range_rev(
3614                excerpt.range.context.start..excerpt_end,
3615                &excerpt.buffer,
3616            ) {
3617                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3618                if hunk_end >= current_position {
3619                    continue;
3620                }
3621                let start =
3622                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3623                        .to_point(self);
3624                return Some(start.row());
3625            }
3626        }
3627
3628        loop {
3629            cursor.prev_excerpt();
3630            let excerpt = cursor.excerpt()?;
3631
3632            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3633                continue;
3634            };
3635            let mut hunks =
3636                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3637            let Some(hunk) = hunks.next() else {
3638                continue;
3639            };
3640            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3641                .to_point(self);
3642            return Some(start.row());
3643        }
3644    }
3645
3646    pub fn has_diff_hunks(&self) -> bool {
3647        self.diffs.values().any(|diff| !diff.is_empty())
3648    }
3649
3650    pub fn is_inside_word<T: ToOffset>(
3651        &self,
3652        position: T,
3653        scope_context: Option<CharScopeContext>,
3654    ) -> bool {
3655        let position = position.to_offset(self);
3656        let classifier = self
3657            .char_classifier_at(position)
3658            .scope_context(scope_context);
3659        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
3660        let prev_char_kind = self
3661            .reversed_chars_at(position)
3662            .next()
3663            .map(|c| classifier.kind(c));
3664        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
3665    }
3666
3667    pub fn surrounding_word<T: ToOffset>(
3668        &self,
3669        start: T,
3670        scope_context: Option<CharScopeContext>,
3671    ) -> (Range<usize>, Option<CharKind>) {
3672        let mut start = start.to_offset(self);
3673        let mut end = start;
3674        let mut next_chars = self.chars_at(start).peekable();
3675        let mut prev_chars = self.reversed_chars_at(start).peekable();
3676
3677        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3678
3679        let word_kind = cmp::max(
3680            prev_chars.peek().copied().map(|c| classifier.kind(c)),
3681            next_chars.peek().copied().map(|c| classifier.kind(c)),
3682        );
3683
3684        for ch in prev_chars {
3685            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3686                start -= ch.len_utf8();
3687            } else {
3688                break;
3689            }
3690        }
3691
3692        for ch in next_chars {
3693            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
3694                end += ch.len_utf8();
3695            } else {
3696                break;
3697            }
3698        }
3699
3700        (start..end, word_kind)
3701    }
3702
3703    pub fn char_kind_before<T: ToOffset>(
3704        &self,
3705        start: T,
3706        scope_context: Option<CharScopeContext>,
3707    ) -> Option<CharKind> {
3708        let start = start.to_offset(self);
3709        let classifier = self.char_classifier_at(start).scope_context(scope_context);
3710        self.reversed_chars_at(start)
3711            .next()
3712            .map(|ch| classifier.kind(ch))
3713    }
3714
3715    pub fn is_singleton(&self) -> bool {
3716        self.singleton
3717    }
3718
3719    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
3720        if self.singleton {
3721            self.excerpts
3722                .iter()
3723                .next()
3724                .map(|e| (&e.id, e.buffer_id, &e.buffer))
3725        } else {
3726            None
3727        }
3728    }
3729
3730    pub fn len(&self) -> usize {
3731        self.diff_transforms.summary().output.len
3732    }
3733
3734    pub fn is_empty(&self) -> bool {
3735        self.excerpts.summary().text.len == 0
3736    }
3737
3738    pub fn widest_line_number(&self) -> u32 {
3739        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
3740        self.excerpts.summary().widest_line_number + 1
3741    }
3742
3743    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
3744        let range = range.start.to_offset(self)..range.end.to_offset(self);
3745        let mut excerpts = self.cursor::<usize, usize>();
3746        excerpts.seek(&range.start);
3747
3748        let mut chunk;
3749        let mut has_trailing_newline;
3750        let excerpt_bytes;
3751        if let Some(region) = excerpts.region() {
3752            let mut bytes = region.buffer.bytes_in_range(
3753                region.buffer_range.start + range.start - region.range.start
3754                    ..(region.buffer_range.start + range.end - region.range.start)
3755                        .min(region.buffer_range.end),
3756            );
3757            chunk = bytes.next().unwrap_or(&[][..]);
3758            excerpt_bytes = Some(bytes);
3759            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
3760            if chunk.is_empty() && has_trailing_newline {
3761                chunk = b"\n";
3762                has_trailing_newline = false;
3763            }
3764        } else {
3765            chunk = &[][..];
3766            excerpt_bytes = None;
3767            has_trailing_newline = false;
3768        };
3769
3770        MultiBufferBytes {
3771            range,
3772            cursor: excerpts,
3773            excerpt_bytes,
3774            has_trailing_newline,
3775            chunk,
3776        }
3777    }
3778
3779    pub fn reversed_bytes_in_range<T: ToOffset>(
3780        &self,
3781        range: Range<T>,
3782    ) -> ReversedMultiBufferBytes<'_> {
3783        let range = range.start.to_offset(self)..range.end.to_offset(self);
3784        let mut chunks = self.reversed_chunks_in_range(range.clone());
3785        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
3786        ReversedMultiBufferBytes {
3787            range,
3788            chunks,
3789            chunk,
3790        }
3791    }
3792
3793    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
3794        let mut cursor = self.cursor::<Point, MultiBufferPoint>();
3795        cursor.seek(&MultiBufferPoint::new(start_row, 0));
3796        let mut result = MultiBufferRows {
3797            point: MultiBufferPoint::new(MultiBufferRow(0), 0),
3798            is_empty: self.excerpts.is_empty(),
3799            is_singleton: self.is_singleton(),
3800            cursor,
3801        };
3802        result.seek(start_row);
3803        result
3804    }
3805
3806    pub fn chunks<T: ToOffset>(
3807        &self,
3808        range: Range<T>,
3809        language_aware: bool,
3810    ) -> MultiBufferChunks<'_> {
3811        let mut chunks = MultiBufferChunks {
3812            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
3813            range: 0..0,
3814            excerpts: self.excerpts.cursor(()),
3815            diff_transforms: self.diff_transforms.cursor(()),
3816            diffs: &self.diffs,
3817            diff_base_chunks: None,
3818            excerpt_chunks: None,
3819            buffer_chunk: None,
3820            language_aware,
3821        };
3822        let range = range.start.to_offset(self)..range.end.to_offset(self);
3823        chunks.seek(range);
3824        chunks
3825    }
3826
3827    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
3828        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
3829    }
3830
3831    pub fn clip_point(&self, point: MultiBufferPoint, bias: Bias) -> MultiBufferPoint {
3832        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
3833    }
3834
3835    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
3836        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
3837    }
3838
3839    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
3840        self.clip_dimension(point.0, bias, |buffer, point, bias| {
3841            buffer.clip_point_utf16(Unclipped(point), bias)
3842        })
3843    }
3844
3845    pub fn offset_to_point(&self, offset: usize) -> MultiBufferPoint {
3846        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
3847    }
3848
3849    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
3850        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
3851    }
3852
3853    pub fn point_to_point_utf16(&self, point: MultiBufferPoint) -> PointUtf16 {
3854        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
3855    }
3856
3857    pub fn point_utf16_to_point(&self, point: PointUtf16) -> MultiBufferPoint {
3858        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
3859    }
3860
3861    pub fn point_to_offset(&self, point: MultiBufferPoint) -> usize {
3862        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
3863    }
3864
3865    pub fn point_to_offset_utf16(&self, point: MultiBufferPoint) -> OffsetUtf16 {
3866        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
3867    }
3868
3869    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
3870        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
3871    }
3872
3873    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
3874        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
3875    }
3876
3877    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
3878        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
3879    }
3880
3881    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> OffsetUtf16 {
3882        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
3883    }
3884
3885    fn clip_dimension<'a, LBD, MBD>(
3886        &'a self,
3887        position: MBD,
3888        bias: Bias,
3889        clip_buffer_position: fn(&text::BufferSnapshot, LBD, Bias) -> LBD,
3890    ) -> MBD
3891    where
3892        LBD: LangBufferDimension,
3893        MBD: MultiBufferDimension<Distance = LBD::Distance>,
3894    {
3895        let mut cursor = self.cursor::<LBD, MBD>();
3896        cursor.seek(&position);
3897        if let Some(region) = cursor.region() {
3898            if position >= region.range.end {
3899                return region.range.end;
3900            }
3901            let overshoot = position.distance_to(region.range.start);
3902            let mut buffer_position = region.buffer_range.start;
3903            buffer_position.add_distance(overshoot);
3904            let clipped_buffer_position =
3905                clip_buffer_position(region.buffer, buffer_position, bias);
3906            let mut position = region.range.start;
3907            position.add_distance(clipped_buffer_position.distance_to(region.buffer_range.start));
3908            position
3909        } else {
3910            MBD::max_position(self)
3911        }
3912    }
3913
3914    fn convert_dimension<'a, MBD, LBD, MBD2, LBD2>(
3915        &'a self,
3916        position: MBD,
3917        convert_buffer_dimension: fn(&text::BufferSnapshot, LBD) -> LBD2,
3918    ) -> MBD2
3919    where
3920        MBD: MultiBufferDimension<Distance = LBD::Distance>,
3921        LBD: LangBufferDimension,
3922        MBD2: MultiBufferDimension<Distance = LBD2>,
3923        LBD2: LangBufferDimension<Distance = LBD2>,
3924    {
3925        let mut cursor = self.cursor::<DimensionPair<LBD, LBD2>, DimensionPair<MBD, MBD2>>();
3926        cursor.seek(&DimensionPair {
3927            key: position,
3928            value: None,
3929        });
3930        if let Some(region) = cursor.region() {
3931            if position >= region.range.end.key {
3932                return region.range.end.value.unwrap();
3933            }
3934            let region_start = region.range.start.key;
3935            let mut buffer_position = region.buffer_range.start.key;
3936            buffer_position.add_distance(position.distance_to(region_start));
3937            let buffer_position_in_2 = convert_buffer_dimension(region.buffer, buffer_position);
3938            let mut result = region.range.start.value.unwrap();
3939            result.add_distance(
3940                buffer_position_in_2.distance_to(region.buffer_range.start.value.unwrap()),
3941            );
3942            result
3943        } else {
3944            MBD2::max_position(&self)
3945        }
3946    }
3947
3948    pub fn point_to_buffer_offset<T: ToOffset>(
3949        &self,
3950        point: T,
3951    ) -> Option<(&BufferSnapshot, usize)> {
3952        let offset = point.to_offset(self);
3953        let mut cursor = self.cursor::<usize, usize>();
3954        cursor.seek(&offset);
3955        let region = cursor.region()?;
3956        let overshoot = offset - region.range.start;
3957        let buffer_offset = region.buffer_range.start + overshoot;
3958        if buffer_offset == region.buffer.len() + 1
3959            && region.has_trailing_newline
3960            && !region.is_main_buffer
3961        {
3962            let main_buffer_position = cursor.main_buffer_position()?;
3963            let buffer_snapshot = &cursor.excerpt()?.buffer;
3964            // remove this assert once we figure out the cause of the panics for #40453
3965            buffer_snapshot
3966                .text
3967                .as_rope()
3968                .assert_char_boundary(main_buffer_position);
3969            return Some((buffer_snapshot, main_buffer_position));
3970        } else if buffer_offset > region.buffer.len() {
3971            return None;
3972        }
3973        // remove this assert once we figure out the cause of the panics for #40453
3974        region
3975            .buffer
3976            .text
3977            .as_rope()
3978            .assert_char_boundary(buffer_offset);
3979        Some((region.buffer, buffer_offset))
3980    }
3981
3982    pub fn point_to_buffer_point(
3983        &self,
3984        point: MultiBufferPoint,
3985    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
3986        let mut cursor = self.cursor::<Point, MultiBufferPoint>();
3987        cursor.seek(&point);
3988        let region = cursor.region()?;
3989        let overshoot = point.distance_to(region.range.start);
3990        let mut buffer_point = region.buffer_range.start;
3991        buffer_point.add_distance(overshoot);
3992        let excerpt = cursor.excerpt()?;
3993        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
3994            && region.has_trailing_newline
3995            && !region.is_main_buffer
3996        {
3997            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
3998        } else if buffer_point > region.buffer.max_point() {
3999            return None;
4000        }
4001        Some((region.buffer, buffer_point, excerpt.id))
4002    }
4003
4004    pub fn suggested_indents(
4005        &self,
4006        rows: impl IntoIterator<Item = MultiBufferRow>,
4007        cx: &App,
4008    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4009        let mut result = BTreeMap::new();
4010
4011        let mut rows_for_excerpt = Vec::new();
4012        let mut cursor = self.cursor::<Point, MultiBufferPoint>();
4013        let mut rows = rows.into_iter().peekable();
4014        let mut prev_row = u32::MAX;
4015        let mut prev_language_indent_size = IndentSize::default();
4016
4017        while let Some(row) = rows.next() {
4018            cursor.seek(&MultiBufferPoint::new(row, 0));
4019            let Some(region) = cursor.region() else {
4020                continue;
4021            };
4022
4023            // Retrieve the language and indent size once for each disjoint region being indented.
4024            let single_indent_size = if row.0.saturating_sub(1) == prev_row {
4025                prev_language_indent_size
4026            } else {
4027                // FIXME these are mutlibuffer rows used for lang buffers??
4028                region
4029                    .buffer
4030                    .language_indent_size_at(Point::new(row.0, 0), cx)
4031            };
4032            prev_language_indent_size = single_indent_size;
4033            prev_row = row.0;
4034
4035            let start_buffer_row = region.buffer_range.start.row;
4036            let start_multibuffer_row = region.range.start.row();
4037            let end_multibuffer_row = region.range.end.row();
4038
4039            rows_for_excerpt.push(row);
4040            while let Some(next_row) = rows.peek().copied() {
4041                if end_multibuffer_row > next_row {
4042                    rows_for_excerpt.push(next_row);
4043                    rows.next();
4044                } else {
4045                    break;
4046                }
4047            }
4048
4049            let buffer_rows = rows_for_excerpt
4050                .drain(..)
4051                .map(|row| start_buffer_row + row.0 - start_multibuffer_row.0);
4052            let buffer_indents = region
4053                .buffer
4054                .suggested_indents(buffer_rows, single_indent_size);
4055            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4056                (
4057                    MultiBufferRow(start_multibuffer_row.0 + row - start_buffer_row),
4058                    indent,
4059                )
4060            });
4061            result.extend(multibuffer_indents);
4062        }
4063
4064        result
4065    }
4066
4067    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4068        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4069            let mut size = buffer.indent_size_for_line(range.start.row);
4070            size.len = size
4071                .len
4072                .min(range.end.column)
4073                .saturating_sub(range.start.column);
4074            size
4075        } else {
4076            IndentSize::spaces(0)
4077        }
4078    }
4079
4080    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4081        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4082            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4083        } else {
4084            LineIndent::spaces(0)
4085        }
4086    }
4087
4088    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4089        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4090
4091        if self.language_settings(cx).extend_comment_on_newline
4092            && let Some(language_scope) = self.language_scope_at(MultiBufferPoint::new(row, 0))
4093        {
4094            let delimiters = language_scope.line_comment_prefixes();
4095            for delimiter in delimiters {
4096                if *self
4097                    .chars_at(MultiBufferPoint::new(row, indent.len() as u32))
4098                    .take(delimiter.chars().count())
4099                    .collect::<String>()
4100                    .as_str()
4101                    == **delimiter
4102                {
4103                    indent.push_str(delimiter);
4104                    break;
4105                }
4106            }
4107        }
4108
4109        indent
4110    }
4111
4112    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4113    where
4114        T: ToOffset,
4115    {
4116        for char in self.reversed_chars_at(position) {
4117            if !char.is_whitespace() {
4118                return false;
4119            }
4120            if char == '\n' {
4121                return true;
4122            }
4123        }
4124        true
4125    }
4126
4127    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4128        while row.0 > 0 {
4129            row.0 -= 1;
4130            if !self.is_line_blank(row) {
4131                return Some(row);
4132            }
4133        }
4134        None
4135    }
4136
4137    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4138        if let Some((_, range)) = self.buffer_line_for_row(row) {
4139            range.end.column - range.start.column
4140        } else {
4141            0
4142        }
4143    }
4144
4145    pub fn buffer_line_for_row(
4146        &self,
4147        row: MultiBufferRow,
4148    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4149        let mut cursor = self.cursor::<Point, MultiBufferPoint>();
4150        let point = MultiBufferPoint::new(row, 0);
4151        cursor.seek(&point);
4152        let region = cursor.region()?;
4153        let overshoot = point.min(region.range.end).distance_to(region.range.start);
4154        let mut buffer_point = region.buffer_range.start;
4155        buffer_point.add_distance(overshoot);
4156        if buffer_point.row > region.buffer_range.end.row {
4157            return None;
4158        }
4159        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4160        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4161            .min(region.buffer_range.end);
4162        Some((region.buffer, line_start..line_end))
4163    }
4164
4165    pub fn max_point(&self) -> MultiBufferPoint {
4166        MultiBufferPoint(self.text_summary().lines)
4167    }
4168
4169    pub fn max_row(&self) -> MultiBufferRow {
4170        MultiBufferRow(self.text_summary().lines.row)
4171    }
4172
4173    pub fn text_summary(&self) -> TextSummary {
4174        self.diff_transforms.summary().output
4175    }
4176
4177    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4178    where
4179        D: TextDimension,
4180        O: ToOffset,
4181    {
4182        let range = range.start.to_offset(self)..range.end.to_offset(self);
4183        let mut cursor = self
4184            .diff_transforms
4185            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4186        cursor.seek(&range.start, Bias::Right);
4187
4188        let Some(first_transform) = cursor.item() else {
4189            return D::from_text_summary(&TextSummary::default());
4190        };
4191
4192        let diff_transform_start = cursor.start().0;
4193        let diff_transform_end = cursor.end().0;
4194        let diff_start = range.start;
4195        let start_overshoot = diff_start - diff_transform_start;
4196        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4197
4198        let mut result = match first_transform {
4199            DiffTransform::BufferContent { .. } => {
4200                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4201                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4202                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4203            }
4204            DiffTransform::DeletedHunk {
4205                buffer_id,
4206                base_text_byte_range,
4207                has_trailing_newline,
4208                ..
4209            } => {
4210                let buffer_start = base_text_byte_range.start + start_overshoot;
4211                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4212                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4213                    panic!("{:?} is in non-existent deleted hunk", range.start)
4214                };
4215
4216                let include_trailing_newline =
4217                    *has_trailing_newline && range.end >= diff_transform_end;
4218                if include_trailing_newline {
4219                    buffer_end -= 1;
4220                }
4221
4222                let mut summary =
4223                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4224
4225                if include_trailing_newline {
4226                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4227                }
4228
4229                summary
4230            }
4231        };
4232        if range.end < diff_transform_end {
4233            return result;
4234        }
4235
4236        cursor.next();
4237        result.add_assign(&D::from_text_summary(
4238            &cursor.summary(&range.end, Bias::Right),
4239        ));
4240
4241        let Some(last_transform) = cursor.item() else {
4242            return result;
4243        };
4244
4245        let overshoot = range.end - cursor.start().0;
4246        let suffix = match last_transform {
4247            DiffTransform::BufferContent { .. } => {
4248                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4249                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4250            }
4251            DiffTransform::DeletedHunk {
4252                base_text_byte_range,
4253                buffer_id,
4254                has_trailing_newline,
4255                ..
4256            } => {
4257                let buffer_end = base_text_byte_range.start + overshoot;
4258                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4259                    panic!("{:?} is in non-existent deleted hunk", range.end)
4260                };
4261
4262                let mut suffix = base_text
4263                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4264                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4265                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4266                }
4267                suffix
4268            }
4269        };
4270
4271        result.add_assign(&suffix);
4272        result
4273    }
4274
4275    fn text_summary_for_excerpt_offset_range<'a, D>(&self, mut range: Range<ExcerptOffset>) -> D
4276    where
4277        D: TextDimension,
4278    {
4279        let mut summary = D::zero(());
4280        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4281        cursor.seek(&range.start, Bias::Right);
4282        if let Some(excerpt) = cursor.item() {
4283            let mut end_before_newline = cursor.end();
4284            if excerpt.has_trailing_newline {
4285                end_before_newline -= ExcerptOffset::new(1);
4286            }
4287
4288            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4289            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4290            let end_in_excerpt =
4291                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4292            summary.add_assign(
4293                &excerpt
4294                    .buffer
4295                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4296            );
4297
4298            if range.end > end_before_newline {
4299                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4300            }
4301
4302            cursor.next();
4303        }
4304
4305        if range.end > *cursor.start() {
4306            summary.add_assign(
4307                &cursor
4308                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4309                    .0,
4310            );
4311            if let Some(excerpt) = cursor.item() {
4312                range.end = cmp::max(*cursor.start(), range.end);
4313
4314                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4315                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4316                summary.add_assign(
4317                    &excerpt
4318                        .buffer
4319                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4320                );
4321            }
4322        }
4323
4324        summary
4325    }
4326
4327    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4328    where
4329        MBD: MultiBufferDimension<
4330            LangBufferDimension : LangBufferDimension,
4331            Distance = <<MBD as MultiBufferDimension>::LangBufferDimension as LangBufferDimension>::Distance,
4332        >,
4333    {
4334        self.summaries_for_anchors([anchor])[0]
4335    }
4336
4337    fn resolve_summary_for_anchor<LBD, MBD>(
4338        &self,
4339        anchor: &Anchor,
4340        excerpt_position: LBD,
4341        diff_transforms: &mut Cursor<
4342            DiffTransform,
4343            Dimensions<ExcerptDimension<LBD>, OutputDimension<MBD>>,
4344        >,
4345    ) -> MBD
4346    where
4347        LBD: LangBufferDimension,
4348        MBD: MultiBufferDimension<Distance = LBD::Distance>,
4349    {
4350        loop {
4351            let transform_end_position = diff_transforms.end().0.0;
4352            let at_transform_end =
4353                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4354            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4355                diff_transforms.next();
4356                continue;
4357            }
4358
4359            let mut position = diff_transforms.start().1.0;
4360            match diff_transforms.item() {
4361                Some(DiffTransform::DeletedHunk {
4362                    buffer_id,
4363                    base_text_byte_range,
4364                    ..
4365                }) => {
4366                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4367                        && let Some(base_text) =
4368                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4369                        && base_text.can_resolve(diff_base_anchor)
4370                    {
4371                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4372                        if base_text_offset >= base_text_byte_range.start
4373                            && base_text_offset <= base_text_byte_range.end
4374                        {
4375                            let position_in_hunk = base_text
4376                                .text_summary_for_range::<MBD::Distance, _>(
4377                                    base_text_byte_range.start..base_text_offset,
4378                                );
4379                            position.add_distance(position_in_hunk);
4380                        } else if at_transform_end {
4381                            diff_transforms.next();
4382                            continue;
4383                        }
4384                    }
4385                }
4386                _ => {
4387                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4388                        diff_transforms.next();
4389                        continue;
4390                    }
4391                    let overshoot = excerpt_position.distance_to(diff_transforms.start().0.0);
4392                    position.add_distance(overshoot);
4393                }
4394            }
4395
4396            return position;
4397        }
4398    }
4399
4400    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4401        let mut cursor = self
4402            .excerpts
4403            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
4404        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4405
4406        cursor.seek(&Some(locator), Bias::Left);
4407        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
4408            cursor.prev();
4409        }
4410
4411        let mut position = cursor.start().1;
4412        if let Some(excerpt) = cursor.item()
4413            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
4414        {
4415            let excerpt_buffer_start = excerpt
4416                .buffer
4417                .offset_for_anchor(&excerpt.range.context.start);
4418            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4419            let buffer_position = cmp::min(
4420                excerpt_buffer_end,
4421                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4422            );
4423            if buffer_position > excerpt_buffer_start {
4424                position.value += buffer_position - excerpt_buffer_start;
4425            }
4426        }
4427        position
4428    }
4429
4430    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4431        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4432            excerpt_id = *replacement;
4433        }
4434        excerpt_id
4435    }
4436
4437    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
4438    where
4439        MBD: MultiBufferDimension<
4440            LangBufferDimension : LangBufferDimension,
4441            Distance = <<MBD as MultiBufferDimension>::LangBufferDimension as LangBufferDimension>::Distance,
4442        >,
4443        I: 'a + IntoIterator<Item = &'a Anchor>,
4444    {
4445        let mut anchors = anchors.into_iter().peekable();
4446        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4447        let mut diff_transforms_cursor = self
4448            .diff_transforms
4449            .cursor::<Dimensions<ExcerptDimension<MBD::LangBufferDimension>, OutputDimension<MBD>>>(
4450                (),
4451            );
4452        diff_transforms_cursor.next();
4453
4454        let mut summaries = Vec::new();
4455        while let Some(anchor) = anchors.peek() {
4456            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4457
4458            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
4459                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
4460            });
4461
4462            let locator = self.excerpt_locator_for_id(excerpt_id);
4463            cursor.seek_forward(locator, Bias::Left);
4464            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
4465                cursor.prev();
4466            }
4467
4468            let excerpt_start_position =
4469                MBD::LangBufferDimension::from_text_summary(&cursor.start().text);
4470            if let Some(excerpt) = cursor.item() {
4471                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4472                    let position = self.resolve_summary_for_anchor(
4473                        &Anchor::min(),
4474                        excerpt_start_position,
4475                        &mut diff_transforms_cursor,
4476                    );
4477                    summaries.extend(excerpt_anchors.map(|_| position));
4478                    continue;
4479                }
4480                let excerpt_buffer_start = excerpt
4481                    .range
4482                    .context
4483                    .start
4484                    .summary::<MBD::LangBufferDimension>(&excerpt.buffer);
4485                let excerpt_buffer_end = excerpt
4486                    .range
4487                    .context
4488                    .end
4489                    .summary::<MBD::LangBufferDimension>(&excerpt.buffer);
4490                for (buffer_summary, anchor) in excerpt
4491                    .buffer
4492                    .summaries_for_anchors_with_payload::<MBD::LangBufferDimension, _, _>(
4493                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4494                    )
4495                {
4496                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4497                    let mut position = excerpt_start_position;
4498                    if summary > excerpt_buffer_start {
4499                        position.add_distance(summary.distance_to(excerpt_buffer_start));
4500                    }
4501
4502                    if position > diff_transforms_cursor.start().0.0 {
4503                        diff_transforms_cursor
4504                            .seek_forward(&ExcerptDimension(position), Bias::Left);
4505                    }
4506
4507                    summaries.push(self.resolve_summary_for_anchor(
4508                        anchor,
4509                        position,
4510                        &mut diff_transforms_cursor,
4511                    ));
4512                }
4513            } else {
4514                diff_transforms_cursor
4515                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
4516                let position = self.resolve_summary_for_anchor(
4517                    &Anchor::max(),
4518                    excerpt_start_position,
4519                    &mut diff_transforms_cursor,
4520                );
4521                summaries.extend(excerpt_anchors.map(|_| position));
4522            }
4523        }
4524
4525        summaries
4526    }
4527
4528    pub fn dimensions_from_points<'a, D>(
4529        &'a self,
4530        points: impl 'a + IntoIterator<Item = MultiBufferPoint>,
4531    ) -> impl 'a + Iterator<Item = D>
4532    where
4533        D: TextDimension + Sub<D, Output = D>,
4534    {
4535        let mut cursor = self.cursor::<Point, DimensionPair<MultiBufferPoint, D>>();
4536        cursor.seek(&DimensionPair {
4537            key: Default::default(),
4538            value: None,
4539        });
4540        let mut points = points.into_iter();
4541        iter::from_fn(move || {
4542            let point = points.next()?;
4543
4544            cursor.seek_forward(&DimensionPair {
4545                key: point,
4546                value: None,
4547            });
4548
4549            if let Some(region) = cursor.region() {
4550                let overshoot = point.distance_to(region.range.start.key);
4551                let mut buffer_point = region.buffer_range.start;
4552                buffer_point.add_distance(overshoot);
4553                let mut position = region.range.start.value.unwrap();
4554                position.add_assign(
4555                    &region
4556                        .buffer
4557                        .text_summary_for_range(region.buffer_range.start..buffer_point),
4558                );
4559                if point == region.range.end.key && region.has_trailing_newline {
4560                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4561                }
4562                Some(position)
4563            } else {
4564                Some(D::from_text_summary(&self.text_summary()))
4565            }
4566        })
4567    }
4568
4569    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4570    where
4571        I: 'a + IntoIterator<Item = &'a Anchor>,
4572    {
4573        let mut anchors = anchors.into_iter().enumerate().peekable();
4574        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4575        cursor.next();
4576
4577        let mut result = Vec::new();
4578
4579        while let Some((_, anchor)) = anchors.peek() {
4580            let old_excerpt_id = anchor.excerpt_id;
4581
4582            // Find the location where this anchor's excerpt should be.
4583            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4584            cursor.seek_forward(&Some(old_locator), Bias::Left);
4585
4586            let next_excerpt = cursor.item();
4587            let prev_excerpt = cursor.prev_item();
4588
4589            // Process all of the anchors for this excerpt.
4590            while let Some((anchor_ix, &anchor)) =
4591                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
4592            {
4593                let mut anchor = anchor;
4594
4595                // Leave min and max anchors unchanged if invalid or
4596                // if the old excerpt still exists at this location
4597                let mut kept_position = next_excerpt
4598                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
4599                    || old_excerpt_id == ExcerptId::max()
4600                    || old_excerpt_id == ExcerptId::min();
4601
4602                // If the old excerpt no longer exists at this location, then attempt to
4603                // find an equivalent position for this anchor in an adjacent excerpt.
4604                if !kept_position {
4605                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4606                        if excerpt.contains(&anchor) {
4607                            anchor.excerpt_id = excerpt.id;
4608                            kept_position = true;
4609                            break;
4610                        }
4611                    }
4612                }
4613
4614                // If there's no adjacent excerpt that contains the anchor's position,
4615                // then report that the anchor has lost its position.
4616                if !kept_position {
4617                    anchor = if let Some(excerpt) = next_excerpt {
4618                        let mut text_anchor = excerpt
4619                            .range
4620                            .context
4621                            .start
4622                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4623                        if text_anchor
4624                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4625                            .is_gt()
4626                        {
4627                            text_anchor = excerpt.range.context.end;
4628                        }
4629                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4630                    } else if let Some(excerpt) = prev_excerpt {
4631                        let mut text_anchor = excerpt
4632                            .range
4633                            .context
4634                            .end
4635                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4636                        if text_anchor
4637                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4638                            .is_lt()
4639                        {
4640                            text_anchor = excerpt.range.context.start;
4641                        }
4642                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4643                    } else if anchor.text_anchor.bias == Bias::Left {
4644                        Anchor::min()
4645                    } else {
4646                        Anchor::max()
4647                    };
4648                }
4649
4650                result.push((anchor_ix, anchor, kept_position));
4651            }
4652        }
4653        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4654        result
4655    }
4656
4657    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
4658        self.anchor_at(position, Bias::Left)
4659    }
4660
4661    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
4662        self.anchor_at(position, Bias::Right)
4663    }
4664
4665    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
4666        let offset = position.to_offset(self);
4667
4668        // Find the given position in the diff transforms. Determine the corresponding
4669        // offset in the excerpts, and whether the position is within a deleted hunk.
4670        let mut diff_transforms = self
4671            .diff_transforms
4672            .cursor::<Dimensions<usize, ExcerptOffset>>(());
4673        diff_transforms.seek(&offset, Bias::Right);
4674
4675        if offset == diff_transforms.start().0
4676            && bias == Bias::Left
4677            && let Some(DiffTransform::DeletedHunk { .. }) = diff_transforms.prev_item()
4678        {
4679            diff_transforms.prev();
4680        }
4681        let offset_in_transform = offset - diff_transforms.start().0;
4682        let mut excerpt_offset = diff_transforms.start().1;
4683        let mut diff_base_anchor = None;
4684        if let Some(DiffTransform::DeletedHunk {
4685            buffer_id,
4686            base_text_byte_range,
4687            has_trailing_newline,
4688            ..
4689        }) = diff_transforms.item()
4690        {
4691            let diff = self.diffs.get(buffer_id).expect("missing diff");
4692            if offset_in_transform > base_text_byte_range.len() {
4693                debug_assert!(*has_trailing_newline);
4694                bias = Bias::Right;
4695            } else {
4696                diff_base_anchor = Some(
4697                    diff.base_text()
4698                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
4699                );
4700                bias = Bias::Left;
4701            }
4702        } else {
4703            excerpt_offset += ExcerptOffset::new(offset_in_transform);
4704        };
4705
4706        let mut excerpts = self
4707            .excerpts
4708            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
4709        excerpts.seek(&excerpt_offset, Bias::Right);
4710        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
4711            excerpts.prev();
4712        }
4713        if let Some(excerpt) = excerpts.item() {
4714            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
4715            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
4716                overshoot -= 1;
4717                bias = Bias::Right;
4718            }
4719
4720            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4721            let text_anchor =
4722                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
4723            let anchor = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor);
4724            match diff_base_anchor {
4725                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
4726                None => anchor,
4727            }
4728        } else if excerpt_offset.is_zero() && bias == Bias::Left {
4729            Anchor::min()
4730        } else {
4731            Anchor::max()
4732        }
4733    }
4734
4735    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
4736    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
4737        let (excerpt, buffer, _) = self.as_singleton()?;
4738        Some(Anchor::in_buffer(*excerpt, buffer, text_anchor))
4739    }
4740
4741    /// Returns an anchor for the given excerpt and text anchor,
4742    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4743    pub fn anchor_range_in_excerpt(
4744        &self,
4745        excerpt_id: ExcerptId,
4746        text_anchor: Range<text::Anchor>,
4747    ) -> Option<Range<Anchor>> {
4748        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4749        let excerpt = self.excerpt(excerpt_id)?;
4750
4751        Some(
4752            self.anchor_in_excerpt_(excerpt, text_anchor.start)?
4753                ..self.anchor_in_excerpt_(excerpt, text_anchor.end)?,
4754        )
4755    }
4756
4757    /// Returns an anchor for the given excerpt and text anchor,
4758    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
4759    pub fn anchor_in_excerpt(
4760        &self,
4761        excerpt_id: ExcerptId,
4762        text_anchor: text::Anchor,
4763    ) -> Option<Anchor> {
4764        let excerpt_id = self.latest_excerpt_id(excerpt_id);
4765        let excerpt = self.excerpt(excerpt_id)?;
4766        self.anchor_in_excerpt_(excerpt, text_anchor)
4767    }
4768
4769    fn anchor_in_excerpt_(&self, excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
4770        match text_anchor.buffer_id {
4771            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
4772            Some(_) => return None,
4773            None if text_anchor == text::Anchor::MAX || text_anchor == text::Anchor::MIN => {
4774                return Some(Anchor::in_buffer(
4775                    excerpt.id,
4776                    excerpt.buffer_id,
4777                    text_anchor,
4778                ));
4779            }
4780            None => return None,
4781        }
4782
4783        let context = &excerpt.range.context;
4784        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
4785            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
4786        {
4787            return None;
4788        }
4789
4790        Some(Anchor::in_buffer(
4791            excerpt.id,
4792            excerpt.buffer_id,
4793            text_anchor,
4794        ))
4795    }
4796
4797    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
4798        Some(self.excerpt(excerpt_id)?.range.context.clone())
4799    }
4800
4801    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
4802        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
4803            true
4804        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
4805            excerpt.buffer.can_resolve(&anchor.text_anchor)
4806        } else {
4807            false
4808        }
4809    }
4810
4811    pub fn excerpts(
4812        &self,
4813    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
4814        self.excerpts
4815            .iter()
4816            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
4817    }
4818
4819    fn cursor<'a, LBD, MBD>(&'a self) -> MultiBufferCursor<'a, LBD, MBD>
4820    where
4821        MBD: MultiBufferDimension<Distance = LBD::Distance>,
4822        LBD: LangBufferDimension,
4823    {
4824        let excerpts = self.excerpts.cursor(());
4825        let diff_transforms = self.diff_transforms.cursor(());
4826        MultiBufferCursor {
4827            excerpts,
4828            diff_transforms,
4829            diffs: &self.diffs,
4830            cached_region: None,
4831        }
4832    }
4833
4834    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
4835        let start_locator = self.excerpt_locator_for_id(excerpt_id);
4836        let mut excerpts = self
4837            .excerpts
4838            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(());
4839        excerpts.seek(&Some(start_locator), Bias::Left);
4840        excerpts.prev();
4841
4842        let mut diff_transforms = self
4843            .diff_transforms
4844            .cursor::<DiffTransforms<usize, usize>>(());
4845        diff_transforms.seek(&excerpts.start().1, Bias::Left);
4846        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
4847            diff_transforms.next();
4848        }
4849
4850        let excerpt = excerpts.item()?;
4851        Some(MultiBufferExcerpt {
4852            excerpt,
4853            offset: diff_transforms.start().output_dimension.0,
4854            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
4855            excerpt_offset: excerpts.start().1.clone(),
4856            diff_transforms,
4857        })
4858    }
4859
4860    pub fn excerpt_boundaries_in_range<R, T>(
4861        &self,
4862        range: R,
4863    ) -> impl Iterator<Item = ExcerptBoundary> + '_
4864    where
4865        R: RangeBounds<T>,
4866        T: ToOffset,
4867    {
4868        let start_offset;
4869        let start = match range.start_bound() {
4870            Bound::Included(start) => {
4871                start_offset = start.to_offset(self);
4872                Bound::Included(start_offset)
4873            }
4874            Bound::Excluded(_) => {
4875                panic!("not supported")
4876            }
4877            Bound::Unbounded => {
4878                start_offset = 0;
4879                Bound::Unbounded
4880            }
4881        };
4882        let end = match range.end_bound() {
4883            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4884            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4885            Bound::Unbounded => Bound::Unbounded,
4886        };
4887        let bounds = (start, end);
4888
4889        let mut cursor = self.cursor::<usize, DimensionPair<usize, Point>>();
4890        cursor.seek(&DimensionPair {
4891            key: start_offset,
4892            value: None,
4893        });
4894
4895        if cursor
4896            .region()
4897            .is_some_and(|region| bounds.contains(&region.range.start.key))
4898        {
4899            cursor.prev_excerpt();
4900        } else {
4901            cursor.seek_to_start_of_current_excerpt();
4902        }
4903        let mut prev_region = cursor.region();
4904
4905        cursor.next_excerpt();
4906
4907        iter::from_fn(move || {
4908            loop {
4909                if self.singleton {
4910                    return None;
4911                }
4912
4913                let next_region = cursor.region()?;
4914                cursor.next_excerpt();
4915                if !bounds.contains(&next_region.range.start.key) {
4916                    prev_region = Some(next_region);
4917                    continue;
4918                }
4919
4920                let next_region_start = next_region.range.start.value.unwrap();
4921                let next_region_end = if let Some(region) = cursor.region() {
4922                    region.range.start.value.unwrap()
4923                } else {
4924                    self.max_point().0
4925                };
4926
4927                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
4928                    id: region.excerpt.id,
4929                    buffer: region.excerpt.buffer.clone(),
4930                    buffer_id: region.excerpt.buffer_id,
4931                    range: region.excerpt.range.clone(),
4932                    end_row: MultiBufferRow(next_region_start.row),
4933                });
4934
4935                let next = ExcerptInfo {
4936                    id: next_region.excerpt.id,
4937                    buffer: next_region.excerpt.buffer.clone(),
4938                    buffer_id: next_region.excerpt.buffer_id,
4939                    range: next_region.excerpt.range.clone(),
4940                    end_row: if next_region.excerpt.has_trailing_newline {
4941                        MultiBufferRow(next_region_end.row - 1)
4942                    } else {
4943                        MultiBufferRow(next_region_end.row)
4944                    },
4945                };
4946
4947                let row = MultiBufferRow(next_region_start.row);
4948
4949                prev_region = Some(next_region);
4950
4951                return Some(ExcerptBoundary { row, prev, next });
4952            }
4953        })
4954    }
4955
4956    pub fn edit_count(&self) -> usize {
4957        self.edit_count
4958    }
4959
4960    pub fn non_text_state_update_count(&self) -> usize {
4961        self.non_text_state_update_count
4962    }
4963
4964    /// Returns the smallest enclosing bracket ranges containing the given range or
4965    /// None if no brackets contain range or the range is not contained in a single
4966    /// excerpt
4967    ///
4968    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
4969    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
4970        &self,
4971        range: Range<T>,
4972        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
4973    ) -> Option<(Range<usize>, Range<usize>)> {
4974        let range = range.start.to_offset(self)..range.end.to_offset(self);
4975        let mut excerpt = self.excerpt_containing(range.clone())?;
4976        let buffer = excerpt.buffer();
4977        let excerpt_buffer_range = excerpt.buffer_range();
4978
4979        // Filter to ranges contained in the excerpt
4980        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
4981            excerpt_buffer_range.contains(&open.start)
4982                && excerpt_buffer_range.contains(&close.end)
4983                && range_filter.is_none_or(|filter| filter(buffer, open, close))
4984        };
4985
4986        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
4987            excerpt.map_range_to_buffer(range),
4988            Some(&range_filter),
4989        )?;
4990
4991        Some((
4992            excerpt.map_range_from_buffer(open),
4993            excerpt.map_range_from_buffer(close),
4994        ))
4995    }
4996
4997    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
4998    /// not contained in a single excerpt
4999    pub fn enclosing_bracket_ranges<T: ToOffset>(
5000        &self,
5001        range: Range<T>,
5002    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5003        let range = range.start.to_offset(self)..range.end.to_offset(self);
5004        let mut excerpt = self.excerpt_containing(range.clone())?;
5005
5006        Some(
5007            excerpt
5008                .buffer()
5009                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5010                .filter_map(move |pair| {
5011                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5012                        Some((
5013                            excerpt.map_range_from_buffer(pair.open_range),
5014                            excerpt.map_range_from_buffer(pair.close_range),
5015                        ))
5016                    } else {
5017                        None
5018                    }
5019                }),
5020        )
5021    }
5022
5023    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5024    /// not contained in a single excerpt
5025    pub fn text_object_ranges<T: ToOffset>(
5026        &self,
5027        range: Range<T>,
5028        options: TreeSitterOptions,
5029    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5030        let range = range.start.to_offset(self)..range.end.to_offset(self);
5031        self.excerpt_containing(range.clone())
5032            .map(|mut excerpt| {
5033                excerpt
5034                    .buffer()
5035                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5036                    .filter_map(move |(range, text_object)| {
5037                        if excerpt.contains_buffer_range(range.clone()) {
5038                            Some((excerpt.map_range_from_buffer(range), text_object))
5039                        } else {
5040                            None
5041                        }
5042                    })
5043            })
5044            .into_iter()
5045            .flatten()
5046    }
5047
5048    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5049    /// not contained in a single excerpt
5050    pub fn bracket_ranges<T: ToOffset>(
5051        &self,
5052        range: Range<T>,
5053    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5054        let range = range.start.to_offset(self)..range.end.to_offset(self);
5055        let mut excerpt = self.excerpt_containing(range.clone())?;
5056
5057        Some(
5058            excerpt
5059                .buffer()
5060                .bracket_ranges(excerpt.map_range_to_buffer(range))
5061                .filter_map(move |pair| {
5062                    let buffer_range = pair.open_range.start..pair.close_range.end;
5063                    if excerpt.contains_buffer_range(buffer_range) {
5064                        Some((
5065                            excerpt.map_range_from_buffer(pair.open_range),
5066                            excerpt.map_range_from_buffer(pair.close_range),
5067                        ))
5068                    } else {
5069                        None
5070                    }
5071                }),
5072        )
5073    }
5074
5075    pub fn redacted_ranges<'a, T: ToOffset>(
5076        &'a self,
5077        range: Range<T>,
5078        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5079    ) -> impl Iterator<Item = Range<usize>> + 'a {
5080        let range = range.start.to_offset(self)..range.end.to_offset(self);
5081        self.lift_buffer_metadata::<usize, _, _, _>(range, move |buffer, range| {
5082            if redaction_enabled(buffer.file()) {
5083                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5084            } else {
5085                None
5086            }
5087        })
5088        .map(|(range, _, _, _)| range)
5089    }
5090
5091    pub fn runnable_ranges(
5092        &self,
5093        range: Range<Anchor>,
5094    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5095        let range = range.start.to_offset(self)..range.end.to_offset(self);
5096        self.lift_buffer_metadata(range, move |buffer, range| {
5097            Some(
5098                buffer
5099                    .runnable_ranges(range.clone())
5100                    .filter(move |runnable| {
5101                        runnable.run_range.start >= range.start
5102                            && runnable.run_range.end < range.end
5103                    })
5104                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5105            )
5106        })
5107        .map(|(_, run_range, runnable, _)| language::RunnableRange {
5108            run_range,
5109            ..runnable
5110        })
5111    }
5112
5113    pub fn line_indents(
5114        &self,
5115        start_row: MultiBufferRow,
5116        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5117    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5118        let max_point = self.max_point();
5119        let mut cursor = self.cursor::<Point, MultiBufferPoint>();
5120        cursor.seek(&MultiBufferPoint::new(start_row, 0));
5121        iter::from_fn(move || {
5122            let mut region = cursor.region()?;
5123            while !buffer_filter(&region.excerpt.buffer) {
5124                cursor.next();
5125                region = cursor.region()?;
5126            }
5127            let overshoot = start_row.0.saturating_sub(region.range.start.row().0);
5128            let buffer_start_row =
5129                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5130
5131            let buffer_end_row = if region.is_main_buffer
5132                && (region.has_trailing_newline || region.range.end == max_point)
5133            {
5134                region.buffer_range.end.row
5135            } else {
5136                region.buffer_range.end.row.saturating_sub(1)
5137            };
5138
5139            let line_indents = region
5140                .buffer
5141                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5142            cursor.next();
5143            Some(line_indents.map(move |(buffer_row, indent)| {
5144                let row = region.range.start.row().0 + (buffer_row - region.buffer_range.start.row);
5145                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5146            }))
5147        })
5148        .flatten()
5149    }
5150
5151    pub fn reversed_line_indents(
5152        &self,
5153        end_row: MultiBufferRow,
5154        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5155    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5156        let max_point = self.max_point();
5157        let mut cursor = self.cursor::<Point, MultiBufferPoint>();
5158        cursor.seek(&MultiBufferPoint::new(end_row, 0));
5159        iter::from_fn(move || {
5160            let mut region = cursor.region()?;
5161            while !buffer_filter(&region.excerpt.buffer) {
5162                cursor.prev();
5163                region = cursor.region()?;
5164            }
5165
5166            let buffer_start_row = region.buffer_range.start.row;
5167            let buffer_end_row = if region.is_main_buffer
5168                && (region.has_trailing_newline || region.range.end == max_point)
5169            {
5170                region.buffer_range.end.row + 1
5171            } else {
5172                region.buffer_range.end.row
5173            };
5174
5175            let overshoot = end_row - region.range.start.row();
5176            let buffer_end_row =
5177                (region.buffer_range.start.row + overshoot.0 + 1).min(buffer_end_row);
5178
5179            let line_indents = region
5180                .buffer
5181                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5182            cursor.prev();
5183            Some(line_indents.map(move |(buffer_row, indent)| {
5184                let row = region.range.start.row().0 + (buffer_row - region.buffer_range.start.row);
5185                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5186            }))
5187        })
5188        .flatten()
5189    }
5190
5191    pub async fn enclosing_indent(
5192        &self,
5193        mut target_row: MultiBufferRow,
5194    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5195        let max_row = self.max_point().row();
5196        if target_row >= max_row {
5197            return None;
5198        }
5199
5200        let mut target_indent = self.line_indent_for_row(target_row);
5201
5202        // If the current row is at the start of an indented block, we want to return this
5203        // block as the enclosing indent.
5204        if !target_indent.is_line_empty() && target_row < max_row {
5205            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5206            if !next_line_indent.is_line_empty()
5207                && target_indent.raw_len() < next_line_indent.raw_len()
5208            {
5209                target_indent = next_line_indent;
5210                target_row.0 += 1;
5211            }
5212        }
5213
5214        const SEARCH_ROW_LIMIT: u32 = 25000;
5215        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5216        const YIELD_INTERVAL: u32 = 100;
5217
5218        let mut accessed_row_counter = 0;
5219
5220        // If there is a blank line at the current row, search for the next non indented lines
5221        if target_indent.is_line_empty() {
5222            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5223            let end =
5224                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5225
5226            let mut non_empty_line_above = None;
5227            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5228                if row < start {
5229                    break;
5230                }
5231                accessed_row_counter += 1;
5232                if accessed_row_counter == YIELD_INTERVAL {
5233                    accessed_row_counter = 0;
5234                    yield_now().await;
5235                }
5236                if !indent.is_line_empty() {
5237                    non_empty_line_above = Some((row, indent));
5238                    break;
5239                }
5240            }
5241
5242            let mut non_empty_line_below = None;
5243            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5244                if row > end {
5245                    break;
5246                }
5247                accessed_row_counter += 1;
5248                if accessed_row_counter == YIELD_INTERVAL {
5249                    accessed_row_counter = 0;
5250                    yield_now().await;
5251                }
5252                if !indent.is_line_empty() {
5253                    non_empty_line_below = Some((row, indent));
5254                    break;
5255                }
5256            }
5257
5258            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5259                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5260                    if above_indent.raw_len() >= below_indent.raw_len() {
5261                        (above_row, above_indent)
5262                    } else {
5263                        (below_row, below_indent)
5264                    }
5265                }
5266                (Some(above), None) => above,
5267                (None, Some(below)) => below,
5268                _ => return None,
5269            };
5270
5271            target_indent = indent;
5272            target_row = row;
5273        }
5274
5275        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5276        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5277
5278        let mut start_indent = None;
5279        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5280            if row < start {
5281                break;
5282            }
5283            accessed_row_counter += 1;
5284            if accessed_row_counter == YIELD_INTERVAL {
5285                accessed_row_counter = 0;
5286                yield_now().await;
5287            }
5288            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5289                start_indent = Some((row, indent));
5290                break;
5291            }
5292        }
5293        let (start_row, start_indent_size) = start_indent?;
5294
5295        let mut end_indent = (end, None);
5296        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5297            if row > end {
5298                break;
5299            }
5300            accessed_row_counter += 1;
5301            if accessed_row_counter == YIELD_INTERVAL {
5302                accessed_row_counter = 0;
5303                yield_now().await;
5304            }
5305            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5306                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5307                break;
5308            }
5309        }
5310        let (end_row, end_indent_size) = end_indent;
5311
5312        let indent = if let Some(end_indent_size) = end_indent_size {
5313            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5314                start_indent_size
5315            } else {
5316                end_indent_size
5317            }
5318        } else {
5319            start_indent_size
5320        };
5321
5322        Some((start_row..end_row, indent))
5323    }
5324
5325    pub fn indent_guides_in_range<T: ToPoint>(
5326        &self,
5327        range: Range<T>,
5328        ignore_disabled_for_language: bool,
5329        cx: &App,
5330    ) -> impl Iterator<Item = IndentGuide> {
5331        let range = range.start.to_point(self)..range.end.to_point(self);
5332        let start_row = range.start.row();
5333        let end_row = range.end.row();
5334
5335        let mut row_indents = self.line_indents(start_row, |buffer| {
5336            let settings =
5337                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5338            settings.indent_guides.enabled || ignore_disabled_for_language
5339        });
5340
5341        let mut result = Vec::new();
5342        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5343
5344        let mut prev_settings = None;
5345        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5346            if first_row > end_row {
5347                break;
5348            }
5349            let current_depth = indent_stack.len() as u32;
5350
5351            // Avoid retrieving the language settings repeatedly for every buffer row.
5352            if let Some((prev_buffer_id, _)) = &prev_settings
5353                && prev_buffer_id != &buffer.remote_id()
5354            {
5355                prev_settings.take();
5356            }
5357            let settings = &prev_settings
5358                .get_or_insert_with(|| {
5359                    (
5360                        buffer.remote_id(),
5361                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5362                    )
5363                })
5364                .1;
5365            let tab_size = settings.tab_size.get();
5366
5367            // When encountering empty, continue until found useful line indent
5368            // then add to the indent stack with the depth found
5369            let mut found_indent = false;
5370            let mut last_row = first_row;
5371            if line_indent.is_line_blank() {
5372                while !found_indent {
5373                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5374                        break;
5375                    };
5376                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5377                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5378                        break;
5379                    }
5380
5381                    if new_line_indent.is_line_blank() {
5382                        continue;
5383                    }
5384                    last_row = target_row.min(end_row);
5385                    line_indent = new_line_indent;
5386                    found_indent = true;
5387                    break;
5388                }
5389            } else {
5390                found_indent = true
5391            }
5392
5393            let depth = if found_indent {
5394                line_indent.len(tab_size) / tab_size
5395            } else {
5396                0
5397            };
5398
5399            match depth.cmp(&current_depth) {
5400                cmp::Ordering::Less => {
5401                    for _ in 0..(current_depth - depth) {
5402                        let mut indent = indent_stack.pop().unwrap();
5403                        if last_row != first_row {
5404                            // In this case, we landed on an empty row, had to seek forward,
5405                            // and discovered that the indent we where on is ending.
5406                            // This means that the last display row must
5407                            // be on line that ends this indent range, so we
5408                            // should display the range up to the first non-empty line
5409                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5410                        }
5411
5412                        result.push(indent)
5413                    }
5414                }
5415                cmp::Ordering::Greater => {
5416                    for next_depth in current_depth..depth {
5417                        indent_stack.push(IndentGuide {
5418                            buffer_id: buffer.remote_id(),
5419                            start_row: first_row,
5420                            end_row: last_row,
5421                            depth: next_depth,
5422                            tab_size,
5423                            settings: settings.indent_guides.clone(),
5424                        });
5425                    }
5426                }
5427                _ => {}
5428            }
5429
5430            for indent in indent_stack.iter_mut() {
5431                indent.end_row = last_row;
5432            }
5433        }
5434
5435        result.extend(indent_stack);
5436        result.into_iter()
5437    }
5438
5439    pub fn trailing_excerpt_update_count(&self) -> usize {
5440        self.trailing_excerpt_update_count
5441    }
5442
5443    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5444        self.point_to_buffer_offset(point)
5445            .and_then(|(buffer, _)| buffer.file())
5446    }
5447
5448    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5449        self.point_to_buffer_offset(point)
5450            .and_then(|(buffer, offset)| buffer.language_at(offset))
5451    }
5452
5453    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5454        self.excerpts
5455            .first()
5456            .map(|excerpt| &excerpt.buffer)
5457            .map(|buffer| {
5458                language_settings(
5459                    buffer.language().map(|language| language.name()),
5460                    buffer.file(),
5461                    cx,
5462                )
5463            })
5464            .unwrap_or_else(move || self.language_settings_at(0, cx))
5465    }
5466
5467    pub fn language_settings_at<'a, T: ToOffset>(
5468        &'a self,
5469        point: T,
5470        cx: &'a App,
5471    ) -> Cow<'a, LanguageSettings> {
5472        let mut language = None;
5473        let mut file = None;
5474        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5475            language = buffer.language_at(offset);
5476            file = buffer.file();
5477        }
5478        language_settings(language.map(|l| l.name()), file, cx)
5479    }
5480
5481    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5482        self.point_to_buffer_offset(point)
5483            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5484    }
5485
5486    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5487        self.point_to_buffer_offset(point)
5488            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5489            .unwrap_or_default()
5490    }
5491
5492    pub fn language_indent_size_at<T: ToOffset>(
5493        &self,
5494        position: T,
5495        cx: &App,
5496    ) -> Option<IndentSize> {
5497        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5498        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5499    }
5500
5501    pub fn is_dirty(&self) -> bool {
5502        self.is_dirty
5503    }
5504
5505    pub fn has_deleted_file(&self) -> bool {
5506        self.has_deleted_file
5507    }
5508
5509    pub fn has_conflict(&self) -> bool {
5510        self.has_conflict
5511    }
5512
5513    pub fn has_diagnostics(&self) -> bool {
5514        self.excerpts
5515            .iter()
5516            .any(|excerpt| excerpt.buffer.has_diagnostics())
5517    }
5518
5519    pub fn diagnostic_group(
5520        &self,
5521        buffer_id: BufferId,
5522        group_id: usize,
5523    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
5524        self.lift_buffer_metadata::<Point, MultiBufferPoint, _, _>(
5525            MultiBufferPoint::zero()..self.max_point(),
5526            move |buffer, range| {
5527                if buffer.remote_id() != buffer_id {
5528                    return None;
5529                };
5530                Some(
5531                    buffer
5532                        .diagnostics_in_range(range, false)
5533                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
5534                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
5535                )
5536            },
5537        )
5538        .map(|(_, range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5539    }
5540
5541    pub fn diagnostics_in_range<'a, T>(
5542        &'a self,
5543        range: Range<T>,
5544    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, T>> + 'a
5545    where
5546        T: 'a + text::ToOffset + text::FromAnchor + Ord + Sub<Output = T> + fmt::Debug + Default,
5547        T: MultiBufferDimension<Distance = usize>,
5548    {
5549        self.lift_buffer_metadata::<usize, _, _, _>(range, move |buffer, buffer_range| {
5550            Some(
5551                buffer
5552                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5553                    .map(|entry| (entry.range, entry.diagnostic)),
5554            )
5555        })
5556        .map(|(range, _, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5557    }
5558
5559    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD, LBD>(
5560        &'a self,
5561        range: Range<MBD>,
5562    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, LBD>)> + 'a
5563    where
5564        MBD: MultiBufferDimension<Distance = LBD::Distance> + 'a,
5565        LBD: LangBufferDimension + text::ToOffset + text::FromAnchor,
5566    {
5567        self.lift_buffer_metadata::<LBD, MBD, _, _>(range, move |buffer, buffer_range| {
5568            Some(
5569                buffer
5570                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5571                    .map(|entry| (entry.range, entry.diagnostic)),
5572            )
5573        })
5574        .map(|(_, range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
5575    }
5576
5577    pub fn syntax_ancestor<T: ToOffset>(
5578        &self,
5579        range: Range<T>,
5580    ) -> Option<(tree_sitter::Node<'_>, Range<usize>)> {
5581        let range = range.start.to_offset(self)..range.end.to_offset(self);
5582        let mut excerpt = self.excerpt_containing(range.clone())?;
5583        let node = excerpt
5584            .buffer()
5585            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5586        let node_range = node.byte_range();
5587        if !excerpt.contains_buffer_range(node_range.clone()) {
5588            return None;
5589        };
5590        Some((node, excerpt.map_range_from_buffer(node_range)))
5591    }
5592
5593    pub fn syntax_next_sibling<T: ToOffset>(
5594        &self,
5595        range: Range<T>,
5596    ) -> Option<tree_sitter::Node<'_>> {
5597        let range = range.start.to_offset(self)..range.end.to_offset(self);
5598        let mut excerpt = self.excerpt_containing(range.clone())?;
5599        excerpt
5600            .buffer()
5601            .syntax_next_sibling(excerpt.map_range_to_buffer(range))
5602    }
5603
5604    pub fn syntax_prev_sibling<T: ToOffset>(
5605        &self,
5606        range: Range<T>,
5607    ) -> Option<tree_sitter::Node<'_>> {
5608        let range = range.start.to_offset(self)..range.end.to_offset(self);
5609        let mut excerpt = self.excerpt_containing(range.clone())?;
5610        excerpt
5611            .buffer()
5612            .syntax_prev_sibling(excerpt.map_range_to_buffer(range))
5613    }
5614
5615    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5616        let (excerpt_id, _, buffer) = self.as_singleton()?;
5617        let outline = buffer.outline(theme);
5618        Some(Outline::new(
5619            outline
5620                .items
5621                .into_iter()
5622                .flat_map(|item| {
5623                    Some(OutlineItem {
5624                        depth: item.depth,
5625                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
5626                        text: item.text,
5627                        highlight_ranges: item.highlight_ranges,
5628                        name_ranges: item.name_ranges,
5629                        body_range: item.body_range.and_then(|body_range| {
5630                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
5631                        }),
5632                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5633                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
5634                        }),
5635                    })
5636                })
5637                .collect(),
5638        ))
5639    }
5640
5641    pub fn symbols_containing<T: ToOffset>(
5642        &self,
5643        offset: T,
5644        theme: Option<&SyntaxTheme>,
5645    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5646        let anchor = self.anchor_before(offset);
5647        let excerpt_id = anchor.excerpt_id;
5648        let excerpt = self.excerpt(excerpt_id)?;
5649        let buffer_id = excerpt.buffer_id;
5650        Some((
5651            buffer_id,
5652            excerpt
5653                .buffer
5654                .symbols_containing(anchor.text_anchor, theme)
5655                .into_iter()
5656                .flat_map(|item| {
5657                    Some(OutlineItem {
5658                        depth: item.depth,
5659                        range: Anchor::range_in_buffer(excerpt_id, buffer_id, item.range),
5660                        text: item.text,
5661                        highlight_ranges: item.highlight_ranges,
5662                        name_ranges: item.name_ranges,
5663                        body_range: item.body_range.map(|body_range| {
5664                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5665                        }),
5666                        annotation_range: item.annotation_range.map(|body_range| {
5667                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
5668                        }),
5669                    })
5670                })
5671                .collect(),
5672        ))
5673    }
5674
5675    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
5676        if id == ExcerptId::min() {
5677            Locator::min_ref()
5678        } else if id == ExcerptId::max() {
5679            Locator::max_ref()
5680        } else {
5681            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
5682            if let Some(entry) = item
5683                && entry.id == id
5684            {
5685                return &entry.locator;
5686            }
5687            panic!("invalid excerpt id {id:?}")
5688        }
5689    }
5690
5691    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
5692    fn excerpt_locators_for_ids(
5693        &self,
5694        ids: impl IntoIterator<Item = ExcerptId>,
5695    ) -> SmallVec<[Locator; 1]> {
5696        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
5697        sorted_ids.sort_unstable();
5698        sorted_ids.dedup();
5699        let mut locators = SmallVec::new();
5700
5701        while sorted_ids.last() == Some(&ExcerptId::max()) {
5702            sorted_ids.pop();
5703            locators.push(Locator::max());
5704        }
5705
5706        let mut sorted_ids = sorted_ids.into_iter().peekable();
5707        locators.extend(
5708            sorted_ids
5709                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
5710                .map(|_| Locator::min()),
5711        );
5712
5713        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
5714        for id in sorted_ids {
5715            if cursor.seek_forward(&id, Bias::Left) {
5716                locators.push(cursor.item().unwrap().locator.clone());
5717            } else {
5718                panic!("invalid excerpt id {:?}", id);
5719            }
5720        }
5721
5722        locators.sort_unstable();
5723        locators
5724    }
5725
5726    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
5727        Some(self.excerpt(excerpt_id)?.buffer_id)
5728    }
5729
5730    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
5731        Some(&self.excerpt(excerpt_id)?.buffer)
5732    }
5733
5734    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<MultiBufferPoint>> {
5735        let mut cursor = self
5736            .excerpts
5737            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
5738        let locator = self.excerpt_locator_for_id(excerpt_id);
5739        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
5740        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5741            sought_exact = true;
5742            cursor.prev();
5743        } else if excerpt_id == ExcerptId::min() {
5744            sought_exact = true;
5745        }
5746        if sought_exact {
5747            let start = cursor.start().1.clone();
5748            let end = cursor.end().1;
5749            let mut diff_transforms = self
5750                .diff_transforms
5751                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<MultiBufferPoint>>>(
5752                    (),
5753                );
5754            diff_transforms.seek(&start, Bias::Left);
5755            let overshoot = start.0 - diff_transforms.start().0.0;
5756            let mut start = diff_transforms.start().1.0;
5757            start.add_distance(overshoot);
5758            diff_transforms.seek(&end, Bias::Right);
5759            let overshoot = end.0 - diff_transforms.start().0.0;
5760            let mut end = diff_transforms.start().1.0;
5761            end.add_distance(overshoot);
5762            Some(start..end)
5763        } else {
5764            None
5765        }
5766    }
5767
5768    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
5769        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5770        let locator = self.excerpt_locator_for_id(excerpt_id);
5771        cursor.seek(&Some(locator), Bias::Left);
5772        if let Some(excerpt) = cursor.item()
5773            && excerpt.id == excerpt_id
5774        {
5775            return Some(excerpt);
5776        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5777            cursor.prev();
5778            return cursor.item();
5779        }
5780        None
5781    }
5782
5783    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
5784    pub fn excerpt_containing<T: ToOffset>(
5785        &self,
5786        range: Range<T>,
5787    ) -> Option<MultiBufferExcerpt<'_>> {
5788        let range = range.start.to_offset(self)..range.end.to_offset(self);
5789        let mut cursor = self.cursor::<usize, usize>();
5790        cursor.seek(&range.start);
5791
5792        let start_excerpt = cursor.excerpt()?;
5793        if range.end != range.start {
5794            cursor.seek_forward(&range.end);
5795            if cursor.excerpt()?.id != start_excerpt.id {
5796                return None;
5797            }
5798        }
5799
5800        cursor.seek_to_start_of_current_excerpt();
5801        let region = cursor.region()?;
5802        let offset = region.range.start;
5803        let buffer_offset = start_excerpt.buffer_start_offset();
5804        let excerpt_offset = cursor.excerpts.start().clone();
5805        Some(MultiBufferExcerpt {
5806            diff_transforms: cursor.diff_transforms,
5807            excerpt: start_excerpt,
5808            offset,
5809            buffer_offset,
5810            excerpt_offset,
5811        })
5812    }
5813
5814    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
5815        if let Some(id) = anchor.buffer_id {
5816            return Some(id);
5817        }
5818        let excerpt = self.excerpt_containing(anchor..anchor)?;
5819        Some(excerpt.buffer_id())
5820    }
5821
5822    pub fn selections_in_range<'a>(
5823        &'a self,
5824        range: &'a Range<Anchor>,
5825        include_local: bool,
5826    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
5827        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5828        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
5829        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
5830        cursor.seek(start_locator, Bias::Left);
5831        cursor
5832            .take_while(move |excerpt| excerpt.locator <= *end_locator)
5833            .flat_map(move |excerpt| {
5834                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
5835                if excerpt.id == range.start.excerpt_id {
5836                    query_range.start = range.start.text_anchor;
5837                }
5838                if excerpt.id == range.end.excerpt_id {
5839                    query_range.end = range.end.text_anchor;
5840                }
5841
5842                excerpt
5843                    .buffer
5844                    .selections_in_range(query_range, include_local)
5845                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
5846                        selections.map(move |selection| {
5847                            let mut start =
5848                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.start);
5849                            let mut end =
5850                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.end);
5851                            if range.start.cmp(&start, self).is_gt() {
5852                                start = range.start;
5853                            }
5854                            if range.end.cmp(&end, self).is_lt() {
5855                                end = range.end;
5856                            }
5857
5858                            (
5859                                replica_id,
5860                                line_mode,
5861                                cursor_shape,
5862                                Selection {
5863                                    id: selection.id,
5864                                    start,
5865                                    end,
5866                                    reversed: selection.reversed,
5867                                    goal: selection.goal,
5868                                },
5869                            )
5870                        })
5871                    })
5872            })
5873    }
5874
5875    pub fn show_headers(&self) -> bool {
5876        self.show_headers
5877    }
5878
5879    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
5880        self.diffs.get(&buffer_id)
5881    }
5882
5883    /// Visually annotates a position or range with the `Debug` representation of a value. The
5884    /// callsite of this function is used as a key - previous annotations will be removed.
5885    #[cfg(debug_assertions)]
5886    #[track_caller]
5887    pub fn debug<V, R>(&self, ranges: &R, value: V)
5888    where
5889        R: debug::ToMultiBufferDebugRanges,
5890        V: std::fmt::Debug,
5891    {
5892        self.debug_with_key(std::panic::Location::caller(), ranges, value);
5893    }
5894
5895    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
5896    /// debug annotations with the same key will be removed. The key is also used to determine the
5897    /// annotation's color.
5898    #[cfg(debug_assertions)]
5899    #[track_caller]
5900    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
5901    where
5902        K: std::hash::Hash + 'static,
5903        R: debug::ToMultiBufferDebugRanges,
5904        V: std::fmt::Debug,
5905    {
5906        let text_ranges = ranges
5907            .to_multi_buffer_debug_ranges(self)
5908            .into_iter()
5909            .flat_map(|range| {
5910                self.range_to_buffer_ranges(range).into_iter().map(
5911                    |(buffer, range, _excerpt_id)| {
5912                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
5913                    },
5914                )
5915            })
5916            .collect();
5917        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
5918            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
5919        });
5920    }
5921}
5922
5923#[cfg(any(test, feature = "test-support"))]
5924impl MultiBufferSnapshot {
5925    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
5926        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
5927        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
5928        start..end
5929    }
5930
5931    #[cfg(any(test, feature = "test-support"))]
5932    fn check_invariants(&self) {
5933        let excerpts = self.excerpts.items(());
5934        let excerpt_ids = self.excerpt_ids.items(());
5935
5936        for (ix, excerpt) in excerpts.iter().enumerate() {
5937            if ix == 0 {
5938                if excerpt.locator <= Locator::min() {
5939                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
5940                }
5941            } else if excerpt.locator <= excerpts[ix - 1].locator {
5942                panic!("excerpts are out-of-order: {:?}", excerpts);
5943            }
5944        }
5945
5946        for (ix, entry) in excerpt_ids.iter().enumerate() {
5947            if ix == 0 {
5948                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
5949                    panic!("invalid first excerpt id {:?}", entry.id);
5950                }
5951            } else if entry.id <= excerpt_ids[ix - 1].id {
5952                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
5953            }
5954        }
5955
5956        if self.diff_transforms.summary().input != self.excerpts.summary().text {
5957            panic!(
5958                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
5959                self.excerpts.summary().text.len,
5960                self.diff_transforms.summary().input,
5961                self.diff_transforms.items(()),
5962            );
5963        }
5964
5965        let mut prev_transform: Option<&DiffTransform> = None;
5966        for item in self.diff_transforms.iter() {
5967            if let DiffTransform::BufferContent {
5968                summary,
5969                inserted_hunk_info,
5970            } = item
5971            {
5972                if let Some(DiffTransform::BufferContent {
5973                    inserted_hunk_info: prev_inserted_hunk_info,
5974                    ..
5975                }) = prev_transform
5976                    && *inserted_hunk_info == *prev_inserted_hunk_info
5977                {
5978                    panic!(
5979                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
5980                        self.diff_transforms.items(())
5981                    );
5982                }
5983                if summary.len == 0 && !self.is_empty() {
5984                    panic!("empty buffer content transform");
5985                }
5986            }
5987            prev_transform = Some(item);
5988        }
5989    }
5990}
5991
5992fn add_d_to_bd<LBD, MBD>(bd: &mut LBD, d: MBD)
5993where
5994    LBD: AddAssign<MBD>,
5995{
5996    *bd += d;
5997}
5998
5999fn add_bd_to_d<LBD, MBD>(d: &mut MBD, bd: LBD)
6000where
6001    MBD: AddAssign<LBD>,
6002{
6003    *d += bd;
6004}
6005
6006impl<'a, LBD, MBD> MultiBufferCursor<'a, LBD, MBD>
6007where
6008    LBD: LangBufferDimension,
6009    MBD: MultiBufferDimension<Distance = LBD::Distance>,
6010{
6011    fn seek(&mut self, position: &MBD) {
6012        self.cached_region.take();
6013        self.diff_transforms
6014            .seek(&OutputDimension(*position), Bias::Right);
6015        if self.diff_transforms.item().is_none()
6016            && *position == self.diff_transforms.start().output_dimension.0
6017        {
6018            self.diff_transforms.prev();
6019        }
6020
6021        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6022        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6023            let overshoot = position.distance_to(self.diff_transforms.start().output_dimension.0);
6024            excerpt_position.add_distance(overshoot);
6025        }
6026
6027        self.excerpts
6028            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
6029        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6030            self.excerpts.prev();
6031        }
6032    }
6033
6034    fn seek_forward(&mut self, position: &MBD) {
6035        self.cached_region.take();
6036        self.diff_transforms
6037            .seek_forward(&OutputDimension(*position), Bias::Right);
6038        if self.diff_transforms.item().is_none()
6039            && *position == self.diff_transforms.start().output_dimension.0
6040        {
6041            self.diff_transforms.prev();
6042        }
6043
6044        let overshoot = position.distance_to(self.diff_transforms.start().output_dimension.0);
6045        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6046        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6047            excerpt_position.add_distance(overshoot);
6048        }
6049
6050        self.excerpts
6051            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
6052        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6053            self.excerpts.prev();
6054        }
6055    }
6056
6057    fn next_excerpt(&mut self) {
6058        self.excerpts.next();
6059        self.seek_to_start_of_current_excerpt();
6060    }
6061
6062    fn prev_excerpt(&mut self) {
6063        self.excerpts.prev();
6064        self.seek_to_start_of_current_excerpt();
6065    }
6066
6067    fn seek_to_start_of_current_excerpt(&mut self) {
6068        self.cached_region.take();
6069        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6070        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6071            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6072            && self.diff_transforms.next_item().is_some()
6073        {
6074            self.diff_transforms.next();
6075        }
6076    }
6077
6078    fn next(&mut self) {
6079        self.cached_region.take();
6080        match self
6081            .diff_transforms
6082            .end()
6083            .excerpt_dimension
6084            .cmp(&self.excerpts.end())
6085        {
6086            cmp::Ordering::Less => self.diff_transforms.next(),
6087            cmp::Ordering::Greater => self.excerpts.next(),
6088            cmp::Ordering::Equal => {
6089                self.diff_transforms.next();
6090                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6091                    || self.diff_transforms.item().is_none()
6092                {
6093                    self.excerpts.next();
6094                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6095                    self.diff_transforms.item()
6096                    && self
6097                        .excerpts
6098                        .item()
6099                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6100                {
6101                    self.excerpts.next();
6102                }
6103            }
6104        }
6105    }
6106
6107    fn prev(&mut self) {
6108        self.cached_region.take();
6109        match self
6110            .diff_transforms
6111            .start()
6112            .excerpt_dimension
6113            .cmp(self.excerpts.start())
6114        {
6115            cmp::Ordering::Less => self.excerpts.prev(),
6116            cmp::Ordering::Greater => self.diff_transforms.prev(),
6117            cmp::Ordering::Equal => {
6118                self.diff_transforms.prev();
6119                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6120                    || self.diff_transforms.item().is_none()
6121                {
6122                    self.excerpts.prev();
6123                }
6124            }
6125        }
6126    }
6127
6128    fn region(&mut self) -> Option<MultiBufferRegion<'a, LBD, MBD>> {
6129        if self.cached_region.is_none() {
6130            self.cached_region = self.build_region();
6131        }
6132        self.cached_region.clone()
6133    }
6134
6135    fn is_at_start_of_excerpt(&mut self) -> bool {
6136        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6137            return false;
6138        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6139            return true;
6140        }
6141
6142        self.diff_transforms.prev();
6143        let prev_transform = self.diff_transforms.item();
6144        self.diff_transforms.next();
6145
6146        prev_transform.is_none_or(|next_transform| {
6147            matches!(next_transform, DiffTransform::BufferContent { .. })
6148        })
6149    }
6150
6151    fn is_at_end_of_excerpt(&mut self) -> bool {
6152        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6153            return false;
6154        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6155            || self.diff_transforms.item().is_none()
6156        {
6157            return true;
6158        }
6159
6160        let next_transform = self.diff_transforms.next_item();
6161        next_transform.is_none_or(|next_transform| match next_transform {
6162            DiffTransform::BufferContent { .. } => true,
6163            DiffTransform::DeletedHunk { hunk_info, .. } => self
6164                .excerpts
6165                .item()
6166                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6167        })
6168    }
6169
6170    fn main_buffer_position(&self) -> Option<LBD> {
6171        let excerpt = self.excerpts.item()?;
6172        let buffer = &excerpt.buffer;
6173        let buffer_context_start = excerpt.range.context.start.summary::<LBD>(buffer);
6174        let mut buffer_start = buffer_context_start;
6175        let overshoot = self
6176            .diff_transforms
6177            .end()
6178            .excerpt_dimension
6179            .0
6180            .distance_to(self.excerpts.start().0);
6181        buffer_start.add_distance(overshoot);
6182        Some(buffer_start)
6183    }
6184
6185    fn build_region(&self) -> Option<MultiBufferRegion<'a, LBD, MBD>> {
6186        let excerpt = self.excerpts.item()?;
6187        match self.diff_transforms.item()? {
6188            DiffTransform::DeletedHunk {
6189                buffer_id,
6190                base_text_byte_range,
6191                has_trailing_newline,
6192                hunk_info,
6193                ..
6194            } => {
6195                let diff = self.diffs.get(buffer_id)?;
6196                let buffer = diff.base_text();
6197                let mut rope_cursor = buffer.as_rope().cursor(0);
6198                let buffer_start = rope_cursor.summary::<LBD>(base_text_byte_range.start);
6199                let buffer_range_len =
6200                    rope_cursor.summary::<LBD::Distance>(base_text_byte_range.end);
6201                let mut buffer_end = buffer_start;
6202                buffer_end.add_distance(buffer_range_len);
6203                let start = self.diff_transforms.start().output_dimension.0;
6204                let end = self.diff_transforms.end().output_dimension.0;
6205                Some(MultiBufferRegion {
6206                    buffer,
6207                    excerpt,
6208                    has_trailing_newline: *has_trailing_newline,
6209                    is_main_buffer: false,
6210                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6211                        hunk_info.hunk_secondary_status,
6212                    )),
6213                    buffer_range: buffer_start..buffer_end,
6214                    range: start..end,
6215                })
6216            }
6217            DiffTransform::BufferContent {
6218                inserted_hunk_info, ..
6219            } => {
6220                let buffer = &excerpt.buffer;
6221                let buffer_context_start = excerpt.range.context.start.summary::<LBD>(buffer);
6222
6223                let mut start = self.diff_transforms.start().output_dimension.0;
6224                let mut buffer_start = buffer_context_start;
6225                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6226                    let overshoot = self
6227                        .excerpts
6228                        .start()
6229                        .0
6230                        .distance_to(self.diff_transforms.start().excerpt_dimension.0);
6231                    start.add_distance(overshoot);
6232                } else {
6233                    let overshoot = self
6234                        .diff_transforms
6235                        .start()
6236                        .excerpt_dimension
6237                        .0
6238                        .distance_to(self.excerpts.start().0);
6239                    buffer_start.add_distance(overshoot);
6240                }
6241
6242                let mut end;
6243                let mut buffer_end;
6244                let has_trailing_newline;
6245                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6246                    let overshoot = self
6247                        .diff_transforms
6248                        .end()
6249                        .excerpt_dimension
6250                        .0
6251                        .distance_to(self.excerpts.start().0);
6252                    end = self.diff_transforms.end().output_dimension.0;
6253                    buffer_end = buffer_context_start;
6254                    buffer_end.add_distance(overshoot);
6255                    has_trailing_newline = false;
6256                } else {
6257                    let overshoot = self
6258                        .excerpts
6259                        .end()
6260                        .0
6261                        .distance_to(self.diff_transforms.start().excerpt_dimension.0);
6262                    end = self.diff_transforms.start().output_dimension.0;
6263                    end.add_distance(overshoot);
6264                    buffer_end = excerpt.range.context.end.summary::<LBD>(buffer);
6265                    has_trailing_newline = excerpt.has_trailing_newline;
6266                };
6267
6268                Some(MultiBufferRegion {
6269                    buffer,
6270                    excerpt,
6271                    has_trailing_newline,
6272                    is_main_buffer: true,
6273                    diff_hunk_status: inserted_hunk_info
6274                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6275                    buffer_range: buffer_start..buffer_end,
6276                    range: start..end,
6277                })
6278            }
6279        }
6280    }
6281
6282    fn excerpt(&self) -> Option<&'a Excerpt> {
6283        self.excerpts.item()
6284    }
6285}
6286
6287impl Excerpt {
6288    fn new(
6289        id: ExcerptId,
6290        locator: Locator,
6291        buffer_id: BufferId,
6292        buffer: BufferSnapshot,
6293        range: ExcerptRange<text::Anchor>,
6294        has_trailing_newline: bool,
6295    ) -> Self {
6296        Excerpt {
6297            id,
6298            locator,
6299            max_buffer_row: range.context.end.to_point(&buffer).row,
6300            text_summary: buffer
6301                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6302            buffer_id,
6303            buffer,
6304            range,
6305            has_trailing_newline,
6306        }
6307    }
6308
6309    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6310        let content_start = self.range.context.start.to_offset(&self.buffer);
6311        let chunks_start = content_start + range.start;
6312        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6313
6314        let has_footer = self.has_trailing_newline
6315            && range.start <= self.text_summary.len
6316            && range.end > self.text_summary.len;
6317
6318        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6319
6320        ExcerptChunks {
6321            excerpt_id: self.id,
6322            content_chunks,
6323            has_footer,
6324        }
6325    }
6326
6327    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6328        let content_start = self.range.context.start.to_offset(&self.buffer);
6329        let chunks_start = content_start + range.start;
6330        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6331        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6332        excerpt_chunks.has_footer = self.has_trailing_newline
6333            && range.start <= self.text_summary.len
6334            && range.end > self.text_summary.len;
6335    }
6336
6337    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6338        if text_anchor
6339            .cmp(&self.range.context.start, &self.buffer)
6340            .is_lt()
6341        {
6342            self.range.context.start
6343        } else if text_anchor
6344            .cmp(&self.range.context.end, &self.buffer)
6345            .is_gt()
6346        {
6347            self.range.context.end
6348        } else {
6349            text_anchor
6350        }
6351    }
6352
6353    fn contains(&self, anchor: &Anchor) -> bool {
6354        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
6355            && self
6356                .range
6357                .context
6358                .start
6359                .cmp(&anchor.text_anchor, &self.buffer)
6360                .is_le()
6361            && self
6362                .range
6363                .context
6364                .end
6365                .cmp(&anchor.text_anchor, &self.buffer)
6366                .is_ge()
6367    }
6368
6369    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6370    fn buffer_start_offset(&self) -> usize {
6371        self.range.context.start.to_offset(&self.buffer)
6372    }
6373
6374    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6375    fn buffer_end_offset(&self) -> usize {
6376        self.buffer_start_offset() + self.text_summary.len
6377    }
6378}
6379
6380impl<'a> MultiBufferExcerpt<'a> {
6381    pub fn id(&self) -> ExcerptId {
6382        self.excerpt.id
6383    }
6384
6385    pub fn buffer_id(&self) -> BufferId {
6386        self.excerpt.buffer_id
6387    }
6388
6389    pub fn start_anchor(&self) -> Anchor {
6390        Anchor::in_buffer(
6391            self.excerpt.id,
6392            self.excerpt.buffer_id,
6393            self.excerpt.range.context.start,
6394        )
6395    }
6396
6397    pub fn end_anchor(&self) -> Anchor {
6398        Anchor::in_buffer(
6399            self.excerpt.id,
6400            self.excerpt.buffer_id,
6401            self.excerpt.range.context.end,
6402        )
6403    }
6404
6405    pub fn buffer(&self) -> &'a BufferSnapshot {
6406        &self.excerpt.buffer
6407    }
6408
6409    pub fn buffer_range(&self) -> Range<usize> {
6410        self.buffer_offset
6411            ..self
6412                .excerpt
6413                .range
6414                .context
6415                .end
6416                .to_offset(&self.excerpt.buffer.text)
6417    }
6418
6419    pub fn start_offset(&self) -> usize {
6420        self.offset
6421    }
6422
6423    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6424    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6425        self.map_range_to_buffer(offset..offset).start
6426    }
6427
6428    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6429    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6430        self.diff_transforms
6431            .seek(&OutputDimension(range.start), Bias::Right);
6432        let start = self.map_offset_to_buffer_internal(range.start);
6433        let end = if range.end > range.start {
6434            self.diff_transforms
6435                .seek_forward(&OutputDimension(range.end), Bias::Right);
6436            self.map_offset_to_buffer_internal(range.end)
6437        } else {
6438            start
6439        };
6440        start..end
6441    }
6442
6443    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6444        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
6445        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6446            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
6447        };
6448        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6449        self.buffer_offset + offset_in_excerpt
6450    }
6451
6452    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6453    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6454        self.map_range_from_buffer(buffer_offset..buffer_offset)
6455            .start
6456    }
6457
6458    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6459    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6460        if buffer_range.start < self.buffer_offset {
6461            log::warn!(
6462                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6463            );
6464            return buffer_range;
6465        }
6466        let overshoot = buffer_range.start - self.buffer_offset;
6467        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6468        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
6469        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
6470            log::warn!(
6471                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6472            );
6473            return buffer_range;
6474        }
6475        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6476        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
6477
6478        let end = if buffer_range.end > buffer_range.start {
6479            let overshoot = buffer_range.end - self.buffer_offset;
6480            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6481            self.diff_transforms
6482                .seek_forward(&excerpt_offset, Bias::Right);
6483            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
6484            self.diff_transforms.start().output_dimension.0 + overshoot
6485        } else {
6486            start
6487        };
6488
6489        start..end
6490    }
6491
6492    /// Returns true if the entirety of the given range is in the buffer's excerpt
6493    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6494        range.start >= self.excerpt.buffer_start_offset()
6495            && range.end <= self.excerpt.buffer_end_offset()
6496    }
6497
6498    pub fn max_buffer_row(&self) -> u32 {
6499        self.excerpt.max_buffer_row
6500    }
6501}
6502
6503impl ExcerptId {
6504    pub fn min() -> Self {
6505        Self(0)
6506    }
6507
6508    pub fn max() -> Self {
6509        Self(u32::MAX)
6510    }
6511
6512    pub fn to_proto(self) -> u64 {
6513        self.0 as _
6514    }
6515
6516    pub fn from_proto(proto: u64) -> Self {
6517        Self(proto as _)
6518    }
6519
6520    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6521        let a = snapshot.excerpt_locator_for_id(*self);
6522        let b = snapshot.excerpt_locator_for_id(*other);
6523        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6524    }
6525}
6526
6527impl From<ExcerptId> for usize {
6528    fn from(val: ExcerptId) -> Self {
6529        val.0 as usize
6530    }
6531}
6532
6533impl fmt::Debug for Excerpt {
6534    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6535        f.debug_struct("Excerpt")
6536            .field("id", &self.id)
6537            .field("locator", &self.locator)
6538            .field("buffer_id", &self.buffer_id)
6539            .field("range", &self.range)
6540            .field("text_summary", &self.text_summary)
6541            .field("has_trailing_newline", &self.has_trailing_newline)
6542            .finish()
6543    }
6544}
6545
6546impl sum_tree::Item for Excerpt {
6547    type Summary = ExcerptSummary;
6548
6549    fn summary(&self, _cx: ()) -> Self::Summary {
6550        let mut text = self.text_summary;
6551        if self.has_trailing_newline {
6552            text += TextSummary::from("\n");
6553        }
6554        ExcerptSummary {
6555            excerpt_id: self.id,
6556            excerpt_locator: self.locator.clone(),
6557            widest_line_number: self.max_buffer_row,
6558            text,
6559        }
6560    }
6561}
6562
6563impl sum_tree::Item for ExcerptIdMapping {
6564    type Summary = ExcerptId;
6565
6566    fn summary(&self, _cx: ()) -> Self::Summary {
6567        self.id
6568    }
6569}
6570
6571impl sum_tree::KeyedItem for ExcerptIdMapping {
6572    type Key = ExcerptId;
6573
6574    fn key(&self) -> Self::Key {
6575        self.id
6576    }
6577}
6578
6579impl DiffTransform {
6580    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6581        match self {
6582            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6583            DiffTransform::BufferContent {
6584                inserted_hunk_info, ..
6585            } => *inserted_hunk_info,
6586        }
6587    }
6588}
6589
6590impl sum_tree::Item for DiffTransform {
6591    type Summary = DiffTransformSummary;
6592
6593    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
6594        match self {
6595            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6596                input: *summary,
6597                output: *summary,
6598            },
6599            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6600                input: TextSummary::default(),
6601                output: *summary,
6602            },
6603        }
6604    }
6605}
6606
6607impl DiffTransformSummary {
6608    fn excerpt_len(&self) -> ExcerptOffset {
6609        ExcerptOffset::new(self.input.len)
6610    }
6611}
6612
6613impl sum_tree::ContextLessSummary for DiffTransformSummary {
6614    fn zero() -> Self {
6615        DiffTransformSummary {
6616            input: TextSummary::default(),
6617            output: TextSummary::default(),
6618        }
6619    }
6620
6621    fn add_summary(&mut self, other: &Self) {
6622        self.input += other.input;
6623        self.output += other.output;
6624    }
6625}
6626
6627impl sum_tree::ContextLessSummary for ExcerptId {
6628    fn zero() -> Self {
6629        Self(0)
6630    }
6631
6632    fn add_summary(&mut self, summary: &Self) {
6633        *self = cmp::max(*self, *summary);
6634    }
6635}
6636
6637impl sum_tree::ContextLessSummary for ExcerptSummary {
6638    fn zero() -> Self {
6639        Self::default()
6640    }
6641
6642    fn add_summary(&mut self, summary: &Self) {
6643        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6644        self.excerpt_locator = summary.excerpt_locator.clone();
6645        Summary::add_summary(&mut self.text, &summary.text, ());
6646        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6647    }
6648}
6649
6650impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6651    fn zero(_cx: ()) -> Self {
6652        Default::default()
6653    }
6654
6655    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6656        self.value += summary.text.len;
6657    }
6658}
6659
6660impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
6661    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6662        Ord::cmp(&self.value, &cursor_location.text.len)
6663    }
6664}
6665
6666impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
6667    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
6668        Ord::cmp(&Some(self), cursor_location)
6669    }
6670}
6671
6672impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
6673    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
6674        Ord::cmp(self, &cursor_location.excerpt_locator)
6675    }
6676}
6677
6678impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
6679    fn zero(_cx: ()) -> Self {
6680        Default::default()
6681    }
6682
6683    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6684        self.value += summary.text.lines;
6685    }
6686}
6687
6688impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
6689    fn zero(_cx: ()) -> Self {
6690        Default::default()
6691    }
6692
6693    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6694        *self = Some(&summary.excerpt_locator);
6695    }
6696}
6697
6698impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
6699    fn zero(_cx: ()) -> Self {
6700        Default::default()
6701    }
6702
6703    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6704        *self = Some(summary.excerpt_id);
6705    }
6706}
6707
6708/// A dimension that compares to a `DiffTransforms::excerpt_dimension`
6709#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6710struct ExcerptDimension<T>(T);
6711
6712/// A dimension that compares to a `DiffTransforms::output_dimension`
6713#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
6714struct OutputDimension<T>(T);
6715
6716impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
6717    fn zero(_: ()) -> Self {
6718        ExcerptOffset::new(0)
6719    }
6720
6721    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6722        self.value += summary.input.len;
6723    }
6724}
6725
6726impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
6727    fn zero(_: ()) -> Self {
6728        ExcerptPoint::new(0, 0)
6729    }
6730
6731    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6732        self.value += summary.input.lines;
6733    }
6734}
6735
6736impl<'a, LBD: TextDimension> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<LBD> {
6737    fn zero(_: ()) -> Self {
6738        ExcerptDimension(LBD::default())
6739    }
6740
6741    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6742        TextDimension::add_assign(&mut self.0, &LBD::from_text_summary(&summary.text))
6743    }
6744}
6745
6746impl<LBD: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
6747    for ExcerptDimension<LBD>
6748{
6749    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
6750        Ord::cmp(&self.0, &LBD::from_text_summary(&cursor_location.input))
6751    }
6752}
6753
6754impl<'a, LBD: LangBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
6755    for ExcerptDimension<LBD>
6756{
6757    fn zero(_: ()) -> Self {
6758        ExcerptDimension(LBD::default())
6759    }
6760
6761    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6762        TextDimension::add_assign(&mut self.0, &LBD::from_text_summary(&summary.input))
6763    }
6764}
6765
6766impl<LBD: LangBufferDimension, MBD: MultiBufferDimension>
6767    sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<LBD, MBD>>
6768    for ExcerptDimension<LBD>
6769{
6770    fn cmp(&self, cursor_location: &DiffTransforms<LBD, MBD>, _: ()) -> cmp::Ordering {
6771        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
6772    }
6773}
6774
6775impl<'a, LBD: LangBufferDimension, MBD: MultiBufferDimension>
6776    sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<LBD, MBD>>
6777    for OutputDimension<MBD>
6778{
6779    fn cmp(&self, cursor_location: &DiffTransforms<LBD, MBD>, _: ()) -> cmp::Ordering {
6780        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
6781    }
6782}
6783
6784impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
6785    for OutputDimension<MBD>
6786{
6787    fn zero(_: ()) -> Self {
6788        OutputDimension(MBD::default())
6789    }
6790
6791    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6792        self.0.add_diff_transform_summary(summary);
6793    }
6794}
6795
6796trait MultiBufferDimension: Ord + Copy {
6797    type Distance: Default;
6798    type LangBufferDimension;
6799    fn default() -> Self;
6800    fn max_position(multi_buffer: &MultiBufferSnapshot) -> Self;
6801    fn distance_to(self, to: Self) -> Self::Distance;
6802    fn add_distance(&mut self, distance: Self::Distance);
6803    fn add_diff_transform_summary(&mut self, summary: &DiffTransformSummary);
6804}
6805trait LangBufferDimension: Default + TextDimension + Ord {
6806    type Distance: Default + TextDimension;
6807    fn distance_to(self, to: Self) -> Self::Distance;
6808    fn add_distance(&mut self, distance: Self::Distance);
6809}
6810
6811impl MultiBufferDimension for MultiBufferPoint {
6812    type Distance = Point;
6813    type LangBufferDimension = Point;
6814    fn default() -> Self {
6815        MultiBufferPoint(Point::default())
6816    }
6817    fn max_position(multi_buffer: &MultiBufferSnapshot) -> Self {
6818        multi_buffer.max_point()
6819    }
6820    fn distance_to(self, to: Self) -> Self::Distance {
6821        self.0 - to.0
6822    }
6823    fn add_distance(&mut self, distance: Self::Distance) {
6824        self.0 += distance;
6825    }
6826    fn add_diff_transform_summary(&mut self, summary: &DiffTransformSummary) {
6827        TextDimension::add_assign(&mut self.0, &Point::from_text_summary(&summary.output))
6828    }
6829}
6830impl MultiBufferDimension for usize {
6831    type Distance = usize;
6832    type LangBufferDimension = usize;
6833    fn default() -> Self {
6834        Default::default()
6835    }
6836    fn max_position(multi_buffer: &MultiBufferSnapshot) -> Self {
6837        multi_buffer.text_summary().len
6838    }
6839    fn distance_to(self, to: Self) -> Self::Distance {
6840        self - to
6841    }
6842    fn add_distance(&mut self, distance: Self::Distance) {
6843        *self += distance;
6844    }
6845    fn add_diff_transform_summary(&mut self, summary: &DiffTransformSummary) {
6846        TextDimension::add_assign(self, &usize::from_text_summary(&summary.output))
6847    }
6848}
6849impl MultiBufferDimension for PointUtf16 {
6850    type Distance = PointUtf16;
6851    type LangBufferDimension = PointUtf16;
6852    fn default() -> Self {
6853        Default::default()
6854    }
6855    fn max_position(multi_buffer: &MultiBufferSnapshot) -> Self {
6856        multi_buffer.text_summary().lines_utf16()
6857    }
6858    fn distance_to(self, to: Self) -> Self::Distance {
6859        self - to
6860    }
6861    fn add_distance(&mut self, distance: Self::Distance) {
6862        *self += distance;
6863    }
6864    fn add_diff_transform_summary(&mut self, summary: &DiffTransformSummary) {
6865        TextDimension::add_assign(self, &PointUtf16::from_text_summary(&summary.output))
6866    }
6867}
6868impl MultiBufferDimension for OffsetUtf16 {
6869    type Distance = OffsetUtf16;
6870    type LangBufferDimension = OffsetUtf16;
6871    fn default() -> Self {
6872        Default::default()
6873    }
6874    fn max_position(multi_buffer: &MultiBufferSnapshot) -> Self {
6875        multi_buffer.text_summary().len_utf16
6876    }
6877    fn distance_to(self, to: Self) -> Self::Distance {
6878        self - to
6879    }
6880    fn add_distance(&mut self, distance: Self::Distance) {
6881        *self += distance;
6882    }
6883    fn add_diff_transform_summary(&mut self, summary: &DiffTransformSummary) {
6884        TextDimension::add_assign(self, &OffsetUtf16::from_text_summary(&summary.output))
6885    }
6886}
6887impl<MBD, T> MultiBufferDimension for DimensionPair<MBD, T>
6888where
6889    Self: Copy,
6890    MBD: MultiBufferDimension,
6891{
6892    type Distance = MBD::Distance;
6893    type LangBufferDimension = DimensionPair<MBD::LangBufferDimension, T>;
6894    fn default() -> Self {
6895        DimensionPair {
6896            key: MBD::default(),
6897            value: None,
6898        }
6899    }
6900    fn max_position(multi_buffer: &MultiBufferSnapshot) -> Self {
6901        DimensionPair {
6902            key: MBD::max_position(multi_buffer),
6903            value: None,
6904        }
6905    }
6906    fn distance_to(self, to: Self) -> Self::Distance {
6907        self.key.distance_to(to.key)
6908    }
6909    fn add_distance(&mut self, distance: Self::Distance) {
6910        self.key.add_distance(distance);
6911    }
6912    fn add_diff_transform_summary(&mut self, summary: &DiffTransformSummary) {
6913        self.key.add_diff_transform_summary(summary);
6914    }
6915}
6916
6917impl LangBufferDimension for usize {
6918    type Distance = usize;
6919    fn distance_to(self, to: Self) -> Self::Distance {
6920        self - to
6921    }
6922    fn add_distance(&mut self, distance: Self::Distance) {
6923        *self += distance;
6924    }
6925}
6926impl LangBufferDimension for Point {
6927    type Distance = Point;
6928    fn distance_to(self, to: Self) -> Self::Distance {
6929        self - to
6930    }
6931    fn add_distance(&mut self, distance: Self::Distance) {
6932        *self += distance;
6933    }
6934}
6935impl LangBufferDimension for PointUtf16 {
6936    type Distance = PointUtf16;
6937    fn distance_to(self, to: Self) -> Self::Distance {
6938        self - to
6939    }
6940    fn add_distance(&mut self, distance: Self::Distance) {
6941        *self += distance;
6942    }
6943}
6944impl LangBufferDimension for OffsetUtf16 {
6945    type Distance = OffsetUtf16;
6946    fn distance_to(self, to: Self) -> Self::Distance {
6947        self - to
6948    }
6949    fn add_distance(&mut self, distance: Self::Distance) {
6950        *self += distance;
6951    }
6952}
6953impl<LBD, T> LangBufferDimension for DimensionPair<LBD, T>
6954where
6955    Self: Copy,
6956    T: TextDimension,
6957    LBD: LangBufferDimension,
6958{
6959    type Distance = LBD::Distance;
6960    fn distance_to(self, to: Self) -> Self::Distance {
6961        self.key.distance_to(to.key)
6962    }
6963    fn add_distance(&mut self, distance: Self::Distance) {
6964        self.key.add_distance(distance);
6965    }
6966}
6967
6968impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
6969    fn zero(_: ()) -> Self {
6970        TextSummary::default()
6971    }
6972
6973    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6974        *self += summary.output
6975    }
6976}
6977
6978impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
6979    fn zero(_: ()) -> Self {
6980        0
6981    }
6982
6983    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6984        *self += summary.output.len
6985    }
6986}
6987
6988impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferPoint {
6989    fn zero(_: ()) -> Self {
6990        MultiBufferPoint::new(MultiBufferRow(0), 0)
6991    }
6992
6993    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
6994        *self += MultiBufferPoint(summary.output.lines)
6995    }
6996}
6997
6998impl MultiBufferRows<'_> {
6999    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7000        self.point = MultiBufferPoint(Point::new(row, 0));
7001        self.cursor.seek(&self.point);
7002    }
7003}
7004
7005impl Iterator for MultiBufferRows<'_> {
7006    type Item = RowInfo;
7007
7008    fn next(&mut self) -> Option<Self::Item> {
7009        if self.is_empty && self.point.row() == MultiBufferRow(0) {
7010            self.point += MultiBufferPoint::new(MultiBufferRow(1), 0);
7011            return Some(RowInfo {
7012                buffer_id: None,
7013                buffer_row: Some(0),
7014                multibuffer_row: Some(MultiBufferRow(0)),
7015                diff_status: None,
7016                expand_info: None,
7017            });
7018        }
7019
7020        let mut region = self.cursor.region()?;
7021        while self.point >= region.range.end {
7022            self.cursor.next();
7023            if let Some(next_region) = self.cursor.region() {
7024                region = next_region;
7025            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7026                let multibuffer_row = self.point.row();
7027                let last_excerpt = self
7028                    .cursor
7029                    .excerpts
7030                    .item()
7031                    .or(self.cursor.excerpts.prev_item())?;
7032                let last_row = last_excerpt
7033                    .range
7034                    .context
7035                    .end
7036                    .to_point(&last_excerpt.buffer)
7037                    .row;
7038
7039                let first_row = last_excerpt
7040                    .range
7041                    .context
7042                    .start
7043                    .to_point(&last_excerpt.buffer)
7044                    .row;
7045
7046                let expand_info = if self.is_singleton {
7047                    None
7048                } else {
7049                    let needs_expand_up = first_row == last_row
7050                        && last_row > 0
7051                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7052                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7053
7054                    if needs_expand_up && needs_expand_down {
7055                        Some(ExpandExcerptDirection::UpAndDown)
7056                    } else if needs_expand_up {
7057                        Some(ExpandExcerptDirection::Up)
7058                    } else if needs_expand_down {
7059                        Some(ExpandExcerptDirection::Down)
7060                    } else {
7061                        None
7062                    }
7063                    .map(|direction| ExpandInfo {
7064                        direction,
7065                        excerpt_id: last_excerpt.id,
7066                    })
7067                };
7068                self.point += MultiBufferPoint::new(MultiBufferRow(1), 0);
7069                return Some(RowInfo {
7070                    buffer_id: Some(last_excerpt.buffer_id),
7071                    buffer_row: Some(last_row),
7072                    multibuffer_row: Some(multibuffer_row),
7073                    diff_status: None,
7074                    expand_info,
7075                });
7076            } else {
7077                return None;
7078            };
7079        }
7080
7081        let overshoot = self.point - region.range.start;
7082        let buffer_point = region.buffer_range.start + overshoot.0;
7083        let expand_info = if self.is_singleton {
7084            None
7085        } else {
7086            let needs_expand_up = self.point.row() == region.range.start.row()
7087                && self.cursor.is_at_start_of_excerpt()
7088                && buffer_point.row > 0;
7089            let needs_expand_down = (region.excerpt.has_trailing_newline
7090                && self.point.row() + 1 == region.range.end.row()
7091                || !region.excerpt.has_trailing_newline
7092                    && self.point.row() == region.range.end.row())
7093                && self.cursor.is_at_end_of_excerpt()
7094                && buffer_point.row < region.buffer.max_point().row;
7095
7096            if needs_expand_up && needs_expand_down {
7097                Some(ExpandExcerptDirection::UpAndDown)
7098            } else if needs_expand_up {
7099                Some(ExpandExcerptDirection::Up)
7100            } else if needs_expand_down {
7101                Some(ExpandExcerptDirection::Down)
7102            } else {
7103                None
7104            }
7105            .map(|direction| ExpandInfo {
7106                direction,
7107                excerpt_id: region.excerpt.id,
7108            })
7109        };
7110
7111        let result = Some(RowInfo {
7112            buffer_id: Some(region.buffer.remote_id()),
7113            buffer_row: Some(buffer_point.row),
7114            multibuffer_row: Some(self.point.row()),
7115            diff_status: region
7116                .diff_hunk_status
7117                .filter(|_| self.point < region.range.end),
7118            expand_info,
7119        });
7120        self.point += MultiBufferPoint::new(MultiBufferRow(1), 0);
7121        result
7122    }
7123}
7124
7125impl<'a> MultiBufferChunks<'a> {
7126    pub fn offset(&self) -> usize {
7127        self.range.start
7128    }
7129
7130    pub fn seek(&mut self, range: Range<usize>) {
7131        self.diff_transforms.seek(&range.end, Bias::Right);
7132        let mut excerpt_end = self.diff_transforms.start().1;
7133        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7134            let overshoot = range.end - self.diff_transforms.start().0;
7135            excerpt_end.value += overshoot;
7136        }
7137
7138        self.diff_transforms.seek(&range.start, Bias::Right);
7139        let mut excerpt_start = self.diff_transforms.start().1;
7140        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7141            let overshoot = range.start - self.diff_transforms.start().0;
7142            excerpt_start.value += overshoot;
7143        }
7144
7145        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7146        self.buffer_chunk.take();
7147        self.range = range;
7148    }
7149
7150    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7151        self.excerpt_offset_range = new_range.clone();
7152        self.excerpts.seek(&new_range.start, Bias::Right);
7153        if let Some(excerpt) = self.excerpts.item() {
7154            let excerpt_start = *self.excerpts.start();
7155            if let Some(excerpt_chunks) = self
7156                .excerpt_chunks
7157                .as_mut()
7158                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7159            {
7160                excerpt.seek_chunks(
7161                    excerpt_chunks,
7162                    (self.excerpt_offset_range.start - excerpt_start).value
7163                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7164                );
7165            } else {
7166                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7167                    (self.excerpt_offset_range.start - excerpt_start).value
7168                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7169                    self.language_aware,
7170                ));
7171            }
7172        } else {
7173            self.excerpt_chunks = None;
7174        }
7175    }
7176
7177    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7178        loop {
7179            if self.excerpt_offset_range.is_empty() {
7180                return None;
7181            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7182                self.excerpt_offset_range.start.value += chunk.text.len();
7183                return Some(chunk);
7184            } else {
7185                self.excerpts.next();
7186                let excerpt = self.excerpts.item()?;
7187                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7188                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7189                    self.language_aware,
7190                ));
7191            }
7192        }
7193    }
7194}
7195
7196impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7197    type Item = &'a str;
7198
7199    fn next(&mut self) -> Option<Self::Item> {
7200        let mut region = self.cursor.region()?;
7201        if self.offset == region.range.start {
7202            self.cursor.prev();
7203            region = self.cursor.region()?;
7204            let start_overshoot = self.start.saturating_sub(region.range.start);
7205            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7206                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7207            ));
7208        }
7209
7210        if self.offset == region.range.end && region.has_trailing_newline {
7211            self.offset -= 1;
7212            Some("\n")
7213        } else {
7214            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7215            self.offset -= chunk.len();
7216            Some(chunk)
7217        }
7218    }
7219}
7220
7221impl<'a> Iterator for MultiBufferChunks<'a> {
7222    type Item = Chunk<'a>;
7223
7224    fn next(&mut self) -> Option<Chunk<'a>> {
7225        if self.range.start >= self.range.end {
7226            return None;
7227        }
7228        if self.range.start == self.diff_transforms.end().0 {
7229            self.diff_transforms.next();
7230        }
7231
7232        let diff_transform_start = self.diff_transforms.start().0;
7233        let diff_transform_end = self.diff_transforms.end().0;
7234        debug_assert!(self.range.start < diff_transform_end);
7235
7236        let diff_transform = self.diff_transforms.item()?;
7237        match diff_transform {
7238            DiffTransform::BufferContent { .. } => {
7239                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7240                    chunk
7241                } else {
7242                    let chunk = self.next_excerpt_chunk().unwrap();
7243                    self.buffer_chunk.insert(chunk)
7244                };
7245
7246                let chunk_end = self.range.start + chunk.text.len();
7247                let diff_transform_end = diff_transform_end.min(self.range.end);
7248
7249                if diff_transform_end < chunk_end {
7250                    let split_idx = diff_transform_end - self.range.start;
7251                    let (before, after) = chunk.text.split_at(split_idx);
7252                    self.range.start = diff_transform_end;
7253                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7254                    let chars = chunk.chars & mask;
7255                    let tabs = chunk.tabs & mask;
7256
7257                    chunk.text = after;
7258                    chunk.chars = chunk.chars >> split_idx;
7259                    chunk.tabs = chunk.tabs >> split_idx;
7260
7261                    Some(Chunk {
7262                        text: before,
7263                        chars,
7264                        tabs,
7265                        ..chunk.clone()
7266                    })
7267                } else {
7268                    self.range.start = chunk_end;
7269                    self.buffer_chunk.take()
7270                }
7271            }
7272            DiffTransform::DeletedHunk {
7273                buffer_id,
7274                base_text_byte_range,
7275                has_trailing_newline,
7276                ..
7277            } => {
7278                let base_text_start =
7279                    base_text_byte_range.start + self.range.start - diff_transform_start;
7280                let base_text_end =
7281                    base_text_byte_range.start + self.range.end - diff_transform_start;
7282                let base_text_end = base_text_end.min(base_text_byte_range.end);
7283
7284                let mut chunks = if let Some((_, mut chunks)) = self
7285                    .diff_base_chunks
7286                    .take()
7287                    .filter(|(id, _)| id == buffer_id)
7288                {
7289                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7290                    {
7291                        chunks.seek(base_text_start..base_text_end);
7292                    }
7293                    chunks
7294                } else {
7295                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7296                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7297                };
7298
7299                let chunk = if let Some(chunk) = chunks.next() {
7300                    self.range.start += chunk.text.len();
7301                    self.diff_base_chunks = Some((*buffer_id, chunks));
7302                    chunk
7303                } else {
7304                    debug_assert!(has_trailing_newline);
7305                    self.range.start += "\n".len();
7306                    Chunk {
7307                        text: "\n",
7308                        chars: 1u128,
7309                        ..Default::default()
7310                    }
7311                };
7312                Some(chunk)
7313            }
7314        }
7315    }
7316}
7317
7318impl MultiBufferBytes<'_> {
7319    fn consume(&mut self, len: usize) {
7320        self.range.start += len;
7321        self.chunk = &self.chunk[len..];
7322
7323        if !self.range.is_empty() && self.chunk.is_empty() {
7324            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7325                self.chunk = chunk;
7326            } else if self.has_trailing_newline {
7327                self.has_trailing_newline = false;
7328                self.chunk = b"\n";
7329            } else {
7330                self.cursor.next();
7331                if let Some(region) = self.cursor.region() {
7332                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7333                        region.buffer_range.start
7334                            ..(region.buffer_range.start + self.range.end - region.range.start)
7335                                .min(region.buffer_range.end),
7336                    );
7337                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7338                    self.excerpt_bytes = Some(excerpt_bytes);
7339                    self.has_trailing_newline =
7340                        region.has_trailing_newline && self.range.end >= region.range.end;
7341                    if self.chunk.is_empty() && self.has_trailing_newline {
7342                        self.has_trailing_newline = false;
7343                        self.chunk = b"\n";
7344                    }
7345                }
7346            }
7347        }
7348    }
7349}
7350
7351impl<'a> Iterator for MultiBufferBytes<'a> {
7352    type Item = &'a [u8];
7353
7354    fn next(&mut self) -> Option<Self::Item> {
7355        let chunk = self.chunk;
7356        if chunk.is_empty() {
7357            None
7358        } else {
7359            self.consume(chunk.len());
7360            Some(chunk)
7361        }
7362    }
7363}
7364
7365impl io::Read for MultiBufferBytes<'_> {
7366    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7367        let len = cmp::min(buf.len(), self.chunk.len());
7368        buf[..len].copy_from_slice(&self.chunk[..len]);
7369        if len > 0 {
7370            self.consume(len);
7371        }
7372        Ok(len)
7373    }
7374}
7375
7376impl io::Read for ReversedMultiBufferBytes<'_> {
7377    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7378        let len = cmp::min(buf.len(), self.chunk.len());
7379        buf[..len].copy_from_slice(&self.chunk[..len]);
7380        buf[..len].reverse();
7381        if len > 0 {
7382            self.range.end -= len;
7383            self.chunk = &self.chunk[..self.chunk.len() - len];
7384            if !self.range.is_empty()
7385                && self.chunk.is_empty()
7386                && let Some(chunk) = self.chunks.next()
7387            {
7388                self.chunk = chunk.as_bytes();
7389            }
7390        }
7391        Ok(len)
7392    }
7393}
7394
7395impl<'a> Iterator for ExcerptChunks<'a> {
7396    type Item = Chunk<'a>;
7397
7398    fn next(&mut self) -> Option<Self::Item> {
7399        if let Some(chunk) = self.content_chunks.next() {
7400            return Some(chunk);
7401        }
7402
7403        if self.has_footer {
7404            let text = "\n";
7405            let chars = 0b1;
7406            self.has_footer = false;
7407            return Some(Chunk {
7408                text,
7409                chars,
7410                ..Default::default()
7411            });
7412        }
7413
7414        None
7415    }
7416}
7417
7418impl ToOffset for MultiBufferPoint {
7419    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7420        snapshot.point_to_offset(*self)
7421    }
7422    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7423        snapshot.point_to_offset_utf16(*self)
7424    }
7425}
7426
7427impl ToOffset for usize {
7428    #[track_caller]
7429    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7430        assert!(
7431            *self <= snapshot.len(),
7432            "offset {} is greater than the snapshot.len() {}",
7433            *self,
7434            snapshot.len(),
7435        );
7436        *self
7437    }
7438    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7439        snapshot.offset_to_offset_utf16(*self)
7440    }
7441}
7442
7443impl ToOffset for OffsetUtf16 {
7444    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7445        snapshot.offset_utf16_to_offset(*self)
7446    }
7447
7448    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7449        *self
7450    }
7451}
7452
7453impl ToOffset for PointUtf16 {
7454    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7455        snapshot.point_utf16_to_offset(*self)
7456    }
7457    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7458        snapshot.point_utf16_to_offset_utf16(*self)
7459    }
7460}
7461
7462impl ToPoint for usize {
7463    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferPoint {
7464        snapshot.offset_to_point(*self)
7465    }
7466    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7467        snapshot.offset_to_point_utf16(*self)
7468    }
7469}
7470
7471impl ToPoint for MultiBufferPoint {
7472    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> MultiBufferPoint {
7473        *self
7474    }
7475    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7476        snapshot.point_to_point_utf16(*self)
7477    }
7478}
7479
7480impl ToPoint for PointUtf16 {
7481    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferPoint {
7482        snapshot.point_utf16_to_point(*self)
7483    }
7484    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7485        *self
7486    }
7487}
7488
7489impl From<ExcerptId> for EntityId {
7490    fn from(id: ExcerptId) -> Self {
7491        EntityId::from(id.0 as u64)
7492    }
7493}
7494
7495#[cfg(debug_assertions)]
7496pub mod debug {
7497    use super::*;
7498
7499    pub trait ToMultiBufferDebugRanges {
7500        fn to_multi_buffer_debug_ranges(&self, snapshot: &MultiBufferSnapshot)
7501        -> Vec<Range<usize>>;
7502    }
7503
7504    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
7505        fn to_multi_buffer_debug_ranges(
7506            &self,
7507            snapshot: &MultiBufferSnapshot,
7508        ) -> Vec<Range<usize>> {
7509            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
7510        }
7511    }
7512
7513    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
7514        fn to_multi_buffer_debug_ranges(
7515            &self,
7516            snapshot: &MultiBufferSnapshot,
7517        ) -> Vec<Range<usize>> {
7518            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
7519                .to_multi_buffer_debug_ranges(snapshot)
7520        }
7521    }
7522
7523    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
7524        fn to_multi_buffer_debug_ranges(
7525            &self,
7526            snapshot: &MultiBufferSnapshot,
7527        ) -> Vec<Range<usize>> {
7528            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7529        }
7530    }
7531
7532    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
7533        fn to_multi_buffer_debug_ranges(
7534            &self,
7535            snapshot: &MultiBufferSnapshot,
7536        ) -> Vec<Range<usize>> {
7537            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7538        }
7539    }
7540
7541    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
7542        fn to_multi_buffer_debug_ranges(
7543            &self,
7544            snapshot: &MultiBufferSnapshot,
7545        ) -> Vec<Range<usize>> {
7546            self.iter()
7547                .map(|item| {
7548                    let offset = item.to_offset(snapshot);
7549                    offset..offset
7550                })
7551                .collect()
7552        }
7553    }
7554
7555    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
7556        fn to_multi_buffer_debug_ranges(
7557            &self,
7558            snapshot: &MultiBufferSnapshot,
7559        ) -> Vec<Range<usize>> {
7560            self.iter()
7561                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
7562                .collect()
7563        }
7564    }
7565}