multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp::{self, Ordering},
  40    fmt,
  41    future::Future,
  42    io,
  43    iter::{self, FromIterator},
  44    mem,
  45    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  46    rc::Rc,
  47    str,
  48    sync::{Arc, OnceLock},
  49    time::Duration,
  50};
  51use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  52use text::{
  53    BufferId, Edit, LineIndent, TextSummary,
  54    locator::Locator,
  55    subscription::{Subscription, Topic},
  56};
  57use theme::SyntaxTheme;
  58use ztracing::instrument;
  59
  60pub use self::path_key::{PathExcerptInsertResult, PathKey};
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68/// One or more [`Buffers`](Buffer) being edited in a single view.
  69///
  70/// See <https://zed.dev/features#multi-buffers>
  71pub struct MultiBuffer {
  72    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  73    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  74    snapshot: RefCell<MultiBufferSnapshot>,
  75    /// Contains the state of the buffers being edited
  76    buffers: BTreeMap<BufferId, BufferState>,
  77    /// Mapping from buffer IDs to their diff states
  78    diffs: HashMap<BufferId, DiffState>,
  79    subscriptions: Topic<MultiBufferOffset>,
  80    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  81    singleton: bool,
  82    /// The history of the multi-buffer.
  83    history: History,
  84    /// The explicit title of the multi-buffer.
  85    /// If `None`, it will be derived from the underlying path or content.
  86    title: Option<String>,
  87    /// The writing capability of the multi-buffer.
  88    capability: Capability,
  89    buffer_changed_since_sync: Rc<Cell<bool>>,
  90}
  91
  92#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
  93pub struct PathKeyIndex(u64);
  94
  95pub struct ExcerptInfo {
  96    path_key: PathKey,
  97    buffer_id: BufferId,
  98    range: ExcerptRange<text::Anchor>,
  99}
 100
 101#[derive(Clone, Debug, PartialEq, Eq)]
 102pub enum Event {
 103    BufferUpdated {
 104        buffer: Entity<Buffer>,
 105        path_key: PathKey,
 106        ranges: Vec<Range<text::Anchor>>,
 107    },
 108    BuffersRemoved {
 109        removed_buffer_ids: Vec<BufferId>,
 110    },
 111    BuffersEdited {
 112        buffer_ids: Vec<BufferId>,
 113    },
 114    DiffHunksToggled,
 115    Edited {
 116        edited_buffer: Option<Entity<Buffer>>,
 117    },
 118    TransactionUndone {
 119        transaction_id: TransactionId,
 120    },
 121    Reloaded,
 122    LanguageChanged(BufferId, bool),
 123    Reparsed(BufferId),
 124    Saved,
 125    FileHandleChanged,
 126    DirtyChanged,
 127    DiagnosticsUpdated,
 128    BufferDiffChanged,
 129}
 130
 131/// A diff hunk, representing a range of consequent lines in a multibuffer.
 132#[derive(Debug, Clone, PartialEq, Eq)]
 133pub struct MultiBufferDiffHunk {
 134    /// The row range in the multibuffer where this diff hunk appears.
 135    pub row_range: Range<MultiBufferRow>,
 136    /// The buffer ID that this hunk belongs to.
 137    pub buffer_id: BufferId,
 138    /// The range of the underlying buffer that this hunk corresponds to.
 139    pub buffer_range: Range<text::Anchor>,
 140    /// The range within the buffer's diff base that this hunk corresponds to.
 141    pub diff_base_byte_range: Range<BufferOffset>,
 142    /// The status of this hunk (added/modified/deleted and secondary status).
 143    pub status: DiffHunkStatus,
 144    /// The word diffs for this hunk.
 145    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 146}
 147
 148impl MultiBufferDiffHunk {
 149    pub fn status(&self) -> DiffHunkStatus {
 150        self.status
 151    }
 152
 153    pub fn is_created_file(&self) -> bool {
 154        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 155            && self.buffer_range.start.is_min()
 156            && self.buffer_range.end.is_max()
 157    }
 158
 159    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 160        let start = Anchor::text(self.buffer_range.start);
 161        let end = Anchor::text(self.buffer_range.end);
 162        start..end
 163    }
 164}
 165
 166pub type MultiBufferPoint = Point;
 167type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 168type ExcerptPoint = ExcerptDimension<Point>;
 169
 170#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 171#[serde(transparent)]
 172pub struct MultiBufferRow(pub u32);
 173
 174impl MultiBufferRow {
 175    pub const MIN: Self = Self(0);
 176    pub const MAX: Self = Self(u32::MAX);
 177}
 178
 179impl ops::Add<usize> for MultiBufferRow {
 180    type Output = Self;
 181
 182    fn add(self, rhs: usize) -> Self::Output {
 183        MultiBufferRow(self.0 + rhs as u32)
 184    }
 185}
 186
 187pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 188    type TextDimension: TextDimension;
 189    fn from_summary(summary: &MBTextSummary) -> Self;
 190
 191    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 192
 193    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 194}
 195
 196// todo(lw): MultiBufferPoint
 197impl MultiBufferDimension for Point {
 198    type TextDimension = Point;
 199    fn from_summary(summary: &MBTextSummary) -> Self {
 200        summary.lines
 201    }
 202
 203    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 204        *self += *other;
 205    }
 206
 207    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 208        *self += summary.lines;
 209    }
 210}
 211
 212// todo(lw): MultiBufferPointUtf16
 213impl MultiBufferDimension for PointUtf16 {
 214    type TextDimension = PointUtf16;
 215    fn from_summary(summary: &MBTextSummary) -> Self {
 216        summary.lines_utf16()
 217    }
 218
 219    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 220        *self += *other;
 221    }
 222
 223    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 224        *self += summary.lines_utf16();
 225    }
 226}
 227
 228#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 229pub struct MultiBufferOffset(pub usize);
 230
 231impl fmt::Display for MultiBufferOffset {
 232    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 233        write!(f, "{}", self.0)
 234    }
 235}
 236
 237impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 238    type Sampler = MultiBufferOffsetUniformSampler;
 239}
 240
 241pub struct MultiBufferOffsetUniformSampler {
 242    sampler: rand::distr::uniform::UniformUsize,
 243}
 244
 245impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 246    type X = MultiBufferOffset;
 247
 248    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 249    where
 250        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 251        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 252    {
 253        let low = *low_b.borrow();
 254        let high = *high_b.borrow();
 255        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 256        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 257    }
 258
 259    #[inline] // if the range is constant, this helps LLVM to do the
 260    // calculations at compile-time.
 261    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 262    where
 263        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 264        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 265    {
 266        let low = *low_b.borrow();
 267        let high = *high_b.borrow();
 268        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 269        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 270    }
 271
 272    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 273        MultiBufferOffset(self.sampler.sample(rng))
 274    }
 275}
 276impl MultiBufferDimension for MultiBufferOffset {
 277    type TextDimension = usize;
 278    fn from_summary(summary: &MBTextSummary) -> Self {
 279        summary.len
 280    }
 281
 282    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 283        self.0 += *other;
 284    }
 285
 286    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 287        *self += summary.len;
 288    }
 289}
 290impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 291    type TextDimension = OffsetUtf16;
 292    fn from_summary(summary: &MBTextSummary) -> Self {
 293        MultiBufferOffsetUtf16(summary.len_utf16)
 294    }
 295
 296    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 297        self.0 += *other;
 298    }
 299
 300    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 301        self.0 += summary.len_utf16;
 302    }
 303}
 304
 305#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 306pub struct BufferOffset(pub usize);
 307
 308impl TextDimension for BufferOffset {
 309    fn from_text_summary(summary: &TextSummary) -> Self {
 310        BufferOffset(usize::from_text_summary(summary))
 311    }
 312    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 313        BufferOffset(usize::from_chunk(chunk))
 314    }
 315    fn add_assign(&mut self, other: &Self) {
 316        TextDimension::add_assign(&mut self.0, &other.0);
 317    }
 318}
 319impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 320    fn zero(cx: ()) -> Self {
 321        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 322    }
 323
 324    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 325        usize::add_summary(&mut self.0, summary, cx);
 326    }
 327}
 328
 329impl Sub for BufferOffset {
 330    type Output = usize;
 331
 332    fn sub(self, other: BufferOffset) -> Self::Output {
 333        self.0 - other.0
 334    }
 335}
 336
 337impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 338    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 339        self.0 += other.key;
 340    }
 341}
 342
 343impl language::ToPoint for BufferOffset {
 344    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 345        self.0.to_point(snapshot)
 346    }
 347}
 348
 349impl language::ToPointUtf16 for BufferOffset {
 350    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 351        self.0.to_point_utf16(snapshot)
 352    }
 353}
 354
 355impl language::ToOffset for BufferOffset {
 356    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 357        self.0.to_offset(snapshot)
 358    }
 359}
 360
 361impl language::ToOffsetUtf16 for BufferOffset {
 362    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 363        self.0.to_offset_utf16(snapshot)
 364    }
 365}
 366
 367#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 368pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 369
 370impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 371    type Output = MultiBufferOffsetUtf16;
 372
 373    fn add(self, rhs: usize) -> Self::Output {
 374        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 375    }
 376}
 377
 378impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 379    type Output = Self;
 380
 381    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 382        MultiBufferOffsetUtf16(self.0 + rhs)
 383    }
 384}
 385
 386impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 387    fn add_assign(&mut self, rhs: OffsetUtf16) {
 388        self.0 += rhs;
 389    }
 390}
 391
 392impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 393    fn add_assign(&mut self, rhs: usize) {
 394        self.0.0 += rhs;
 395    }
 396}
 397
 398impl Sub for MultiBufferOffsetUtf16 {
 399    type Output = OffsetUtf16;
 400
 401    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 402        self.0 - other.0
 403    }
 404}
 405
 406impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 407    type Output = MultiBufferOffsetUtf16;
 408
 409    fn sub(self, other: OffsetUtf16) -> Self::Output {
 410        MultiBufferOffsetUtf16(self.0 - other)
 411    }
 412}
 413
 414#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 415pub struct BufferOffsetUtf16(pub OffsetUtf16);
 416
 417impl MultiBufferOffset {
 418    const ZERO: Self = Self(0);
 419    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 420        self.0.saturating_sub(other.0)
 421    }
 422    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 423        MultiBufferOffset(self.0.saturating_sub(other))
 424    }
 425}
 426
 427impl ops::Sub for MultiBufferOffset {
 428    type Output = usize;
 429
 430    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 431        self.0 - other.0
 432    }
 433}
 434
 435impl ops::Sub<usize> for MultiBufferOffset {
 436    type Output = Self;
 437
 438    fn sub(self, other: usize) -> Self::Output {
 439        MultiBufferOffset(self.0 - other)
 440    }
 441}
 442
 443impl ops::SubAssign<usize> for MultiBufferOffset {
 444    fn sub_assign(&mut self, other: usize) {
 445        self.0 -= other;
 446    }
 447}
 448
 449impl ops::Add<usize> for BufferOffset {
 450    type Output = Self;
 451
 452    fn add(self, rhs: usize) -> Self::Output {
 453        BufferOffset(self.0 + rhs)
 454    }
 455}
 456
 457impl ops::AddAssign<usize> for BufferOffset {
 458    fn add_assign(&mut self, other: usize) {
 459        self.0 += other;
 460    }
 461}
 462
 463impl ops::Add<usize> for MultiBufferOffset {
 464    type Output = Self;
 465
 466    fn add(self, rhs: usize) -> Self::Output {
 467        MultiBufferOffset(self.0 + rhs)
 468    }
 469}
 470
 471impl ops::AddAssign<usize> for MultiBufferOffset {
 472    fn add_assign(&mut self, other: usize) {
 473        self.0 += other;
 474    }
 475}
 476
 477impl ops::Add<isize> for MultiBufferOffset {
 478    type Output = Self;
 479
 480    fn add(self, rhs: isize) -> Self::Output {
 481        MultiBufferOffset((self.0 as isize + rhs) as usize)
 482    }
 483}
 484
 485impl ops::Add for MultiBufferOffset {
 486    type Output = Self;
 487
 488    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 489        MultiBufferOffset(self.0 + rhs.0)
 490    }
 491}
 492
 493impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 494    fn add_assign(&mut self, other: MultiBufferOffset) {
 495        self.0 += other.0;
 496    }
 497}
 498
 499pub trait ToOffset: 'static + fmt::Debug {
 500    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 501    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 502}
 503
 504pub trait ToPoint: 'static + fmt::Debug {
 505    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 506    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 507}
 508
 509struct BufferState {
 510    buffer: Entity<Buffer>,
 511    last_version: RefCell<clock::Global>,
 512    last_non_text_state_update_count: Cell<usize>,
 513    _subscriptions: [gpui::Subscription; 2],
 514}
 515
 516struct DiffState {
 517    diff: Entity<BufferDiff>,
 518    main_buffer: Option<Entity<language::Buffer>>,
 519    _subscription: gpui::Subscription,
 520}
 521
 522impl DiffState {
 523    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 524        DiffStateSnapshot {
 525            diff: self.diff.read(cx).snapshot(cx),
 526            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 527        }
 528    }
 529}
 530
 531#[derive(Clone)]
 532struct DiffStateSnapshot {
 533    diff: BufferDiffSnapshot,
 534    main_buffer: Option<language::BufferSnapshot>,
 535}
 536
 537impl std::ops::Deref for DiffStateSnapshot {
 538    type Target = BufferDiffSnapshot;
 539
 540    fn deref(&self) -> &Self::Target {
 541        &self.diff
 542    }
 543}
 544
 545impl DiffState {
 546    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 547        DiffState {
 548            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 549                BufferDiffEvent::DiffChanged(DiffChanged {
 550                    changed_range,
 551                    base_text_changed_range: _,
 552                    extended_range,
 553                }) => {
 554                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 555                    let range = if use_extended {
 556                        extended_range.clone()
 557                    } else {
 558                        changed_range.clone()
 559                    };
 560                    if let Some(range) = range {
 561                        this.buffer_diff_changed(diff, range, cx)
 562                    }
 563                    cx.emit(Event::BufferDiffChanged);
 564                }
 565                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 566                _ => {}
 567            }),
 568            diff,
 569            main_buffer: None,
 570        }
 571    }
 572
 573    fn new_inverted(
 574        diff: Entity<BufferDiff>,
 575        main_buffer: Entity<language::Buffer>,
 576        cx: &mut Context<MultiBuffer>,
 577    ) -> Self {
 578        let weak_main_buffer = main_buffer.downgrade();
 579        DiffState {
 580            _subscription: cx.subscribe(&diff, {
 581                move |this, diff, event, cx| {
 582                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 583                        return;
 584                    };
 585                    match event {
 586                        BufferDiffEvent::DiffChanged(DiffChanged {
 587                            changed_range: _,
 588                            base_text_changed_range,
 589                            extended_range: _,
 590                        }) => {
 591                            this.inverted_buffer_diff_changed(
 592                                diff,
 593                                main_buffer,
 594                                base_text_changed_range.clone(),
 595                                cx,
 596                            );
 597                            cx.emit(Event::BufferDiffChanged);
 598                        }
 599                        BufferDiffEvent::LanguageChanged => {
 600                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 601                        }
 602                        _ => {}
 603                    }
 604                }
 605            }),
 606            diff,
 607            main_buffer: Some(main_buffer),
 608        }
 609    }
 610}
 611
 612/// The contents of a [`MultiBuffer`] at a single point in time.
 613#[derive(Clone, Default)]
 614pub struct MultiBufferSnapshot {
 615    excerpts: SumTree<Excerpt>,
 616    path_keys_by_buffer: TreeMap<BufferId, PathKey>,
 617    path_keys_by_index: TreeMap<PathKeyIndex, PathKey>,
 618    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 619    diff_transforms: SumTree<DiffTransform>,
 620    non_text_state_update_count: usize,
 621    edit_count: usize,
 622    is_dirty: bool,
 623    has_deleted_file: bool,
 624    has_conflict: bool,
 625    has_inverted_diff: bool,
 626    singleton: bool,
 627    trailing_excerpt_update_count: usize,
 628    all_diff_hunks_expanded: bool,
 629    show_deleted_hunks: bool,
 630    use_extended_diff_range: bool,
 631    show_headers: bool,
 632}
 633
 634#[derive(Debug, Clone)]
 635enum DiffTransform {
 636    BufferContent {
 637        summary: MBTextSummary,
 638        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 639    },
 640    DeletedHunk {
 641        summary: TextSummary,
 642        buffer_id: BufferId,
 643        hunk_info: DiffTransformHunkInfo,
 644        base_text_byte_range: Range<usize>,
 645        has_trailing_newline: bool,
 646    },
 647}
 648
 649#[derive(Clone, Copy, Debug)]
 650struct DiffTransformHunkInfo {
 651    buffer_id: BufferId,
 652    hunk_start_anchor: text::Anchor,
 653    hunk_secondary_status: DiffHunkSecondaryStatus,
 654    is_logically_deleted: bool,
 655}
 656
 657impl Eq for DiffTransformHunkInfo {}
 658
 659impl PartialEq for DiffTransformHunkInfo {
 660    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 661        self.buffer_id == other.buffer_id && self.hunk_start_anchor == other.hunk_start_anchor
 662    }
 663}
 664
 665impl std::hash::Hash for DiffTransformHunkInfo {
 666    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 667        self.buffer_id.hash(state);
 668        self.hunk_start_anchor.hash(state);
 669    }
 670}
 671
 672#[derive(Clone)]
 673pub struct ExcerptBoundaryInfo {
 674    pub buffer: Arc<BufferSnapshot>,
 675    pub buffer_id: BufferId,
 676    pub range: ExcerptRange<text::Anchor>,
 677    pub end_row: MultiBufferRow,
 678}
 679
 680impl std::fmt::Debug for ExcerptBoundaryInfo {
 681    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 682        f.debug_struct(type_name::<Self>())
 683            .field("buffer_id", &self.buffer_id)
 684            .field("path", &self.buffer.file().map(|f| f.path()))
 685            .field("range", &self.range)
 686            .finish()
 687    }
 688}
 689
 690/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 691#[derive(Debug)]
 692pub struct ExcerptBoundary {
 693    pub prev: Option<ExcerptBoundaryInfo>,
 694    pub next: ExcerptBoundaryInfo,
 695    /// The row in the `MultiBuffer` where the boundary is located
 696    pub row: MultiBufferRow,
 697}
 698
 699impl ExcerptBoundary {
 700    pub fn starts_new_buffer(&self) -> bool {
 701        match (self.prev.as_ref(), &self.next) {
 702            (None, _) => true,
 703            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 704        }
 705    }
 706}
 707
 708#[derive(Clone, Debug, PartialEq, Eq)]
 709pub struct ExpandInfo {
 710    pub direction: ExpandExcerptDirection,
 711    pub excerpt_range: Range<text::Anchor>,
 712}
 713
 714#[derive(Clone, Debug, Default, PartialEq, Eq)]
 715pub struct RowInfo {
 716    pub buffer_id: Option<BufferId>,
 717    pub buffer_row: Option<u32>,
 718    pub multibuffer_row: Option<MultiBufferRow>,
 719    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 720    pub expand_info: Option<ExpandInfo>,
 721    pub wrapped_buffer_row: Option<u32>,
 722}
 723
 724/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 725#[derive(Clone)]
 726pub(crate) struct Excerpt {
 727    /// The location of the excerpt in the [`MultiBuffer`]
 728    pub(crate) path_key: PathKey,
 729    pub(crate) path_key_index: PathKeyIndex,
 730    /// A snapshot of the buffer being excerpted
 731    pub(crate) buffer: Arc<BufferSnapshot>,
 732    /// The range of the buffer to be shown in the excerpt
 733    pub(crate) range: ExcerptRange<text::Anchor>,
 734
 735    /// The last row in the excerpted slice of the buffer
 736    pub(crate) max_buffer_row: BufferRow,
 737    /// A summary of the text in the excerpt
 738    pub(crate) text_summary: TextSummary,
 739    pub(crate) has_trailing_newline: bool,
 740}
 741
 742/// A public view into an `Excerpt` in a [`MultiBuffer`].
 743///
 744/// Contains methods for getting the [`Buffer`] of the excerpt,
 745/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 746#[derive(Clone)]
 747pub struct MultiBufferExcerpt<'a> {
 748    excerpt: &'a Excerpt,
 749    diff_transforms:
 750        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 751    /// The offset in the multibuffer considering diff transforms.
 752    offset: MultiBufferOffset,
 753    /// The offset in the multibuffer without diff transforms.
 754    excerpt_offset: ExcerptOffset,
 755    buffer_offset: BufferOffset,
 756}
 757
 758/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 759/// These ranges are relative to the buffer itself
 760#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 761pub struct ExcerptRange<T> {
 762    /// The full range of text to be shown in the excerpt.
 763    pub context: Range<T>,
 764    /// The primary range of text to be highlighted in the excerpt.
 765    /// In a multi-buffer search, this would be the text that matched the search
 766    pub primary: Range<T>,
 767}
 768
 769impl<T: Clone> ExcerptRange<T> {
 770    pub fn new(context: Range<T>) -> Self {
 771        Self {
 772            context: context.clone(),
 773            primary: context,
 774        }
 775    }
 776}
 777
 778impl ExcerptRange<text::Anchor> {
 779    pub fn contains(&self, t: &text::Anchor, snapshot: &BufferSnapshot) -> bool {
 780        self.context.start.cmp(t, snapshot).is_le() && self.context.end.cmp(t, snapshot).is_ge()
 781    }
 782}
 783
 784#[derive(Clone, Debug)]
 785pub struct ExcerptSummary {
 786    path_key: PathKey,
 787    /// End of the excerpt
 788    max_anchor: text::Anchor,
 789    widest_line_number: u32,
 790    text: MBTextSummary,
 791    count: usize,
 792}
 793
 794impl ExcerptSummary {
 795    pub fn min() -> Self {
 796        ExcerptSummary {
 797            path_key: PathKey::min(),
 798            max_anchor: text::Anchor::MIN,
 799            widest_line_number: 0,
 800            text: MBTextSummary::default(),
 801            count: 0,
 802        }
 803    }
 804
 805    pub fn len(&self) -> ExcerptOffset {
 806        ExcerptDimension(self.text.len)
 807    }
 808}
 809
 810#[derive(Debug, Clone)]
 811pub struct DiffTransformSummary {
 812    input: MBTextSummary,
 813    output: MBTextSummary,
 814}
 815
 816/// Summary of a string of text.
 817#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 818pub struct MBTextSummary {
 819    /// Length in bytes.
 820    pub len: MultiBufferOffset,
 821    /// Length in UTF-8.
 822    pub chars: usize,
 823    /// Length in UTF-16 code units
 824    pub len_utf16: OffsetUtf16,
 825    /// A point representing the number of lines and the length of the last line.
 826    ///
 827    /// In other words, it marks the point after the last byte in the text, (if
 828    /// EOF was a character, this would be its position).
 829    pub lines: Point,
 830    /// How many `char`s are in the first line
 831    pub first_line_chars: u32,
 832    /// How many `char`s are in the last line
 833    pub last_line_chars: u32,
 834    /// How many UTF-16 code units are in the last line
 835    pub last_line_len_utf16: u32,
 836    /// The row idx of the longest row
 837    pub longest_row: u32,
 838    /// How many `char`s are in the longest row
 839    pub longest_row_chars: u32,
 840}
 841
 842impl From<TextSummary> for MBTextSummary {
 843    fn from(summary: TextSummary) -> Self {
 844        MBTextSummary {
 845            len: MultiBufferOffset(summary.len),
 846            chars: summary.chars,
 847            len_utf16: summary.len_utf16,
 848            lines: summary.lines,
 849            first_line_chars: summary.first_line_chars,
 850            last_line_chars: summary.last_line_chars,
 851            last_line_len_utf16: summary.last_line_len_utf16,
 852            longest_row: summary.longest_row,
 853            longest_row_chars: summary.longest_row_chars,
 854        }
 855    }
 856}
 857
 858impl From<MBTextSummary> for TextSummary {
 859    fn from(summary: MBTextSummary) -> Self {
 860        TextSummary {
 861            len: summary.len.0,
 862            chars: summary.chars,
 863            len_utf16: summary.len_utf16,
 864            lines: summary.lines,
 865            first_line_chars: summary.first_line_chars,
 866            last_line_chars: summary.last_line_chars,
 867            last_line_len_utf16: summary.last_line_len_utf16,
 868            longest_row: summary.longest_row,
 869            longest_row_chars: summary.longest_row_chars,
 870        }
 871    }
 872}
 873
 874impl From<&str> for MBTextSummary {
 875    fn from(text: &str) -> Self {
 876        MBTextSummary::from(TextSummary::from(text))
 877    }
 878}
 879
 880impl MultiBufferDimension for MBTextSummary {
 881    type TextDimension = TextSummary;
 882
 883    fn from_summary(summary: &MBTextSummary) -> Self {
 884        *summary
 885    }
 886
 887    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 888        *self += *summary;
 889    }
 890
 891    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 892        *self += *summary;
 893    }
 894}
 895
 896impl AddAssign for MBTextSummary {
 897    fn add_assign(&mut self, other: MBTextSummary) {
 898        let joined_chars = self.last_line_chars + other.first_line_chars;
 899        if joined_chars > self.longest_row_chars {
 900            self.longest_row = self.lines.row;
 901            self.longest_row_chars = joined_chars;
 902        }
 903        if other.longest_row_chars > self.longest_row_chars {
 904            self.longest_row = self.lines.row + other.longest_row;
 905            self.longest_row_chars = other.longest_row_chars;
 906        }
 907
 908        if self.lines.row == 0 {
 909            self.first_line_chars += other.first_line_chars;
 910        }
 911
 912        if other.lines.row == 0 {
 913            self.last_line_chars += other.first_line_chars;
 914            self.last_line_len_utf16 += other.last_line_len_utf16;
 915        } else {
 916            self.last_line_chars = other.last_line_chars;
 917            self.last_line_len_utf16 = other.last_line_len_utf16;
 918        }
 919
 920        self.chars += other.chars;
 921        self.len += other.len;
 922        self.len_utf16 += other.len_utf16;
 923        self.lines += other.lines;
 924    }
 925}
 926
 927impl AddAssign<TextSummary> for MBTextSummary {
 928    fn add_assign(&mut self, other: TextSummary) {
 929        *self += MBTextSummary::from(other);
 930    }
 931}
 932
 933impl MBTextSummary {
 934    pub fn lines_utf16(&self) -> PointUtf16 {
 935        PointUtf16 {
 936            row: self.lines.row,
 937            column: self.last_line_len_utf16,
 938        }
 939    }
 940}
 941
 942impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 943where
 944    K: MultiBufferDimension,
 945    V: MultiBufferDimension,
 946{
 947    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 948
 949    fn from_summary(summary: &MBTextSummary) -> Self {
 950        Self {
 951            key: K::from_summary(summary),
 952            value: Some(V::from_summary(summary)),
 953        }
 954    }
 955
 956    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 957        self.key.add_text_dim(&summary.key);
 958        if let Some(value) = &mut self.value {
 959            if let Some(other_value) = summary.value.as_ref() {
 960                value.add_text_dim(other_value);
 961            }
 962        }
 963    }
 964
 965    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 966        self.key.add_mb_text_summary(summary);
 967        if let Some(value) = &mut self.value {
 968            value.add_mb_text_summary(summary);
 969        }
 970    }
 971}
 972
 973#[derive(Clone)]
 974pub struct MultiBufferRows<'a> {
 975    point: Point,
 976    is_empty: bool,
 977    is_singleton: bool,
 978    cursor: MultiBufferCursor<'a, Point, Point>,
 979}
 980
 981pub struct MultiBufferChunks<'a> {
 982    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 983    diff_transforms:
 984        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 985    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 986    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 987    buffer_chunk: Option<Chunk<'a>>,
 988    range: Range<MultiBufferOffset>,
 989    excerpt_offset_range: Range<ExcerptOffset>,
 990    excerpt_chunks: Option<ExcerptChunks<'a>>,
 991    language_aware: bool,
 992}
 993
 994pub struct ReversedMultiBufferChunks<'a> {
 995    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 996    current_chunks: Option<rope::Chunks<'a>>,
 997    start: MultiBufferOffset,
 998    offset: MultiBufferOffset,
 999}
1000
1001pub struct MultiBufferBytes<'a> {
1002    range: Range<MultiBufferOffset>,
1003    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1004    excerpt_bytes: Option<text::Bytes<'a>>,
1005    has_trailing_newline: bool,
1006    chunk: &'a [u8],
1007}
1008
1009pub struct ReversedMultiBufferBytes<'a> {
1010    range: Range<MultiBufferOffset>,
1011    chunks: ReversedMultiBufferChunks<'a>,
1012    chunk: &'a [u8],
1013}
1014
1015#[derive(Clone)]
1016struct DiffTransforms<MBD> {
1017    output_dimension: OutputDimension<MBD>,
1018    excerpt_dimension: ExcerptDimension<MBD>,
1019}
1020
1021impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1022    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1023        Self {
1024            output_dimension: OutputDimension::zero(cx),
1025            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1026                cx,
1027            ),
1028        }
1029    }
1030
1031    fn add_summary(
1032        &mut self,
1033        summary: &'a DiffTransformSummary,
1034        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1035    ) {
1036        self.output_dimension.add_summary(summary, cx);
1037        self.excerpt_dimension.add_summary(summary, cx);
1038    }
1039}
1040
1041#[derive(Clone)]
1042struct MultiBufferCursor<'a, MBD, BD> {
1043    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1044    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1045    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1046    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1047}
1048
1049#[derive(Clone)]
1050struct MultiBufferRegion<'a, MBD, BD> {
1051    buffer: &'a BufferSnapshot,
1052    is_main_buffer: bool,
1053    diff_hunk_status: Option<DiffHunkStatus>,
1054    excerpt: &'a Excerpt,
1055    buffer_range: Range<BD>,
1056    range: Range<MBD>,
1057    has_trailing_newline: bool,
1058}
1059
1060struct ExcerptChunks<'a> {
1061    content_chunks: BufferChunks<'a>,
1062    has_footer: bool,
1063}
1064
1065#[derive(Debug)]
1066struct BufferEdit {
1067    range: Range<BufferOffset>,
1068    new_text: Arc<str>,
1069    is_insertion: bool,
1070    original_indent_column: Option<u32>,
1071}
1072
1073#[derive(Clone, Copy, Debug, PartialEq)]
1074enum DiffChangeKind {
1075    BufferEdited,
1076    DiffUpdated { base_changed: bool },
1077    ExpandOrCollapseHunks { expand: bool },
1078}
1079
1080#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1081pub enum ExpandExcerptDirection {
1082    Up,
1083    Down,
1084    UpAndDown,
1085}
1086
1087impl ExpandExcerptDirection {
1088    pub fn should_expand_up(&self) -> bool {
1089        match self {
1090            ExpandExcerptDirection::Up => true,
1091            ExpandExcerptDirection::Down => false,
1092            ExpandExcerptDirection::UpAndDown => true,
1093        }
1094    }
1095
1096    pub fn should_expand_down(&self) -> bool {
1097        match self {
1098            ExpandExcerptDirection::Up => false,
1099            ExpandExcerptDirection::Down => true,
1100            ExpandExcerptDirection::UpAndDown => true,
1101        }
1102    }
1103}
1104
1105#[derive(Clone, Debug, PartialEq)]
1106pub struct IndentGuide {
1107    pub buffer_id: BufferId,
1108    pub start_row: MultiBufferRow,
1109    pub end_row: MultiBufferRow,
1110    pub depth: u32,
1111    pub tab_size: u32,
1112    pub settings: IndentGuideSettings,
1113}
1114
1115impl IndentGuide {
1116    pub fn indent_level(&self) -> u32 {
1117        self.depth * self.tab_size
1118    }
1119}
1120
1121impl MultiBuffer {
1122    pub fn new(capability: Capability) -> Self {
1123        Self::new_(
1124            capability,
1125            MultiBufferSnapshot {
1126                show_headers: true,
1127                show_deleted_hunks: true,
1128                ..MultiBufferSnapshot::default()
1129            },
1130        )
1131    }
1132
1133    pub fn without_headers(capability: Capability) -> Self {
1134        Self::new_(
1135            capability,
1136            MultiBufferSnapshot {
1137                show_deleted_hunks: true,
1138                ..MultiBufferSnapshot::default()
1139            },
1140        )
1141    }
1142
1143    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1144        let mut this = Self::new_(
1145            buffer.read(cx).capability(),
1146            MultiBufferSnapshot {
1147                singleton: true,
1148                show_deleted_hunks: true,
1149                ..MultiBufferSnapshot::default()
1150            },
1151        );
1152        this.singleton = true;
1153        this.set_excerpts_for_path(
1154            PathKey::sorted(0),
1155            buffer.clone(),
1156            [Point::zero()..buffer.read(cx).max_point()],
1157            0,
1158            cx,
1159        );
1160        this
1161    }
1162
1163    #[inline]
1164    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1165        Self {
1166            snapshot: RefCell::new(snapshot),
1167            buffers: Default::default(),
1168            diffs: HashMap::default(),
1169            subscriptions: Topic::default(),
1170            singleton: false,
1171            capability,
1172            title: None,
1173            buffer_changed_since_sync: Default::default(),
1174            history: History::default(),
1175        }
1176    }
1177
1178    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1179        let mut buffers = BTreeMap::default();
1180        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1181        for (buffer_id, buffer_state) in self.buffers.iter() {
1182            buffer_state.buffer.update(new_cx, |buffer, _| {
1183                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1184            });
1185            buffers.insert(
1186                *buffer_id,
1187                BufferState {
1188                    buffer: buffer_state.buffer.clone(),
1189                    last_version: buffer_state.last_version.clone(),
1190                    last_non_text_state_update_count: buffer_state
1191                        .last_non_text_state_update_count
1192                        .clone(),
1193                    _subscriptions: [
1194                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1195                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1196                    ],
1197                },
1198            );
1199        }
1200        let mut diff_bases = HashMap::default();
1201        for (buffer_id, diff) in self.diffs.iter() {
1202            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1203        }
1204        Self {
1205            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1206            buffers,
1207            diffs: diff_bases,
1208            subscriptions: Default::default(),
1209            singleton: self.singleton,
1210            capability: self.capability,
1211            history: self.history.clone(),
1212            title: self.title.clone(),
1213            buffer_changed_since_sync,
1214        }
1215    }
1216
1217    pub fn set_group_interval(&mut self, group_interval: Duration) {
1218        self.history.set_group_interval(group_interval);
1219    }
1220
1221    pub fn with_title(mut self, title: String) -> Self {
1222        self.title = Some(title);
1223        self
1224    }
1225
1226    pub fn read_only(&self) -> bool {
1227        !self.capability.editable()
1228    }
1229
1230    pub fn capability(&self) -> Capability {
1231        self.capability
1232    }
1233
1234    /// Returns an up-to-date snapshot of the MultiBuffer.
1235    #[ztracing::instrument(skip_all)]
1236    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1237        self.sync(cx);
1238        self.snapshot.borrow().clone()
1239    }
1240
1241    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1242        self.sync(cx);
1243        self.snapshot.borrow()
1244    }
1245
1246    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1247        if self.singleton {
1248            Some(self.buffers.values().next().unwrap().buffer.clone())
1249        } else {
1250            None
1251        }
1252    }
1253
1254    pub fn is_singleton(&self) -> bool {
1255        self.singleton
1256    }
1257
1258    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1259        self.subscriptions.subscribe()
1260    }
1261
1262    pub fn is_dirty(&self, cx: &App) -> bool {
1263        self.read(cx).is_dirty()
1264    }
1265
1266    pub fn has_deleted_file(&self, cx: &App) -> bool {
1267        self.read(cx).has_deleted_file()
1268    }
1269
1270    pub fn has_conflict(&self, cx: &App) -> bool {
1271        self.read(cx).has_conflict()
1272    }
1273
1274    // The `is_empty` signature doesn't match what clippy expects
1275    #[allow(clippy::len_without_is_empty)]
1276    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1277        self.read(cx).len()
1278    }
1279
1280    pub fn is_empty(&self) -> bool {
1281        self.buffers.is_empty()
1282    }
1283
1284    pub fn edit<I, S, T>(
1285        &mut self,
1286        edits: I,
1287        autoindent_mode: Option<AutoindentMode>,
1288        cx: &mut Context<Self>,
1289    ) where
1290        I: IntoIterator<Item = (Range<S>, T)>,
1291        S: ToOffset,
1292        T: Into<Arc<str>>,
1293    {
1294        self.edit_internal(edits, autoindent_mode, true, cx);
1295    }
1296
1297    pub fn edit_non_coalesce<I, S, T>(
1298        &mut self,
1299        edits: I,
1300        autoindent_mode: Option<AutoindentMode>,
1301        cx: &mut Context<Self>,
1302    ) where
1303        I: IntoIterator<Item = (Range<S>, T)>,
1304        S: ToOffset,
1305        T: Into<Arc<str>>,
1306    {
1307        self.edit_internal(edits, autoindent_mode, false, cx);
1308    }
1309
1310    fn edit_internal<I, S, T>(
1311        &mut self,
1312        edits: I,
1313        autoindent_mode: Option<AutoindentMode>,
1314        coalesce_adjacent: bool,
1315        cx: &mut Context<Self>,
1316    ) where
1317        I: IntoIterator<Item = (Range<S>, T)>,
1318        S: ToOffset,
1319        T: Into<Arc<str>>,
1320    {
1321        if self.read_only() || self.buffers.is_empty() {
1322            return;
1323        }
1324        self.sync_mut(cx);
1325        let edits = edits
1326            .into_iter()
1327            .map(|(range, new_text)| {
1328                let mut range = range.start.to_offset(self.snapshot.get_mut())
1329                    ..range.end.to_offset(self.snapshot.get_mut());
1330                if range.start > range.end {
1331                    mem::swap(&mut range.start, &mut range.end);
1332                }
1333                (range, new_text.into())
1334            })
1335            .collect::<Vec<_>>();
1336
1337        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1338
1339        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1340        fn edit_internal(
1341            this: &mut MultiBuffer,
1342            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1343            mut autoindent_mode: Option<AutoindentMode>,
1344            coalesce_adjacent: bool,
1345            cx: &mut Context<MultiBuffer>,
1346        ) {
1347            let original_indent_columns = match &mut autoindent_mode {
1348                Some(AutoindentMode::Block {
1349                    original_indent_columns,
1350                }) => mem::take(original_indent_columns),
1351                _ => Default::default(),
1352            };
1353
1354            let buffer_edits = MultiBuffer::convert_edits_to_buffer_edits(
1355                edits,
1356                this.snapshot.get_mut(),
1357                &original_indent_columns,
1358            );
1359
1360            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1361            for (buffer_id, mut edits) in buffer_edits {
1362                buffer_ids.push(buffer_id);
1363                edits.sort_by_key(|edit| edit.range.start);
1364                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1365                    let mut edits = edits.into_iter().peekable();
1366                    let mut insertions = Vec::new();
1367                    let mut original_indent_columns = Vec::new();
1368                    let mut deletions = Vec::new();
1369                    let empty_str: Arc<str> = Arc::default();
1370                    while let Some(BufferEdit {
1371                        mut range,
1372                        mut new_text,
1373                        mut is_insertion,
1374                        original_indent_column,
1375                    }) = edits.next()
1376                    {
1377                        while let Some(BufferEdit {
1378                            range: next_range,
1379                            is_insertion: next_is_insertion,
1380                            new_text: next_new_text,
1381                            ..
1382                        }) = edits.peek()
1383                        {
1384                            let should_coalesce = if coalesce_adjacent {
1385                                range.end >= next_range.start
1386                            } else {
1387                                range.end > next_range.start
1388                            };
1389
1390                            if should_coalesce {
1391                                range.end = cmp::max(next_range.end, range.end);
1392                                is_insertion |= *next_is_insertion;
1393                                new_text = format!("{new_text}{next_new_text}").into();
1394                                edits.next();
1395                            } else {
1396                                break;
1397                            }
1398                        }
1399
1400                        if is_insertion {
1401                            original_indent_columns.push(original_indent_column);
1402                            insertions.push((
1403                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1404                                new_text.clone(),
1405                            ));
1406                        } else if !range.is_empty() {
1407                            deletions.push((
1408                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1409                                empty_str.clone(),
1410                            ));
1411                        }
1412                    }
1413
1414                    let deletion_autoindent_mode =
1415                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1416                            Some(AutoindentMode::Block {
1417                                original_indent_columns: Default::default(),
1418                            })
1419                        } else {
1420                            autoindent_mode.clone()
1421                        };
1422                    let insertion_autoindent_mode =
1423                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1424                            Some(AutoindentMode::Block {
1425                                original_indent_columns,
1426                            })
1427                        } else {
1428                            autoindent_mode.clone()
1429                        };
1430
1431                    if coalesce_adjacent {
1432                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1433                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1434                    } else {
1435                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1436                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1437                    }
1438                })
1439            }
1440
1441            cx.emit(Event::BuffersEdited { buffer_ids });
1442        }
1443    }
1444
1445    fn convert_edits_to_buffer_edits(
1446        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1447        snapshot: &MultiBufferSnapshot,
1448        original_indent_columns: &[Option<u32>],
1449    ) -> HashMap<BufferId, Vec<BufferEdit>> {
1450        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1451        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1452        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1453            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1454
1455            cursor.seek(&range.start);
1456            let mut start_region = cursor.region().expect("start offset out of bounds");
1457            if !start_region.is_main_buffer {
1458                cursor.next();
1459                if let Some(region) = cursor.region() {
1460                    start_region = region;
1461                } else {
1462                    continue;
1463                }
1464            }
1465
1466            if range.end < start_region.range.start {
1467                continue;
1468            }
1469
1470            let start_region = start_region.clone();
1471            if range.end > start_region.range.end {
1472                cursor.seek_forward(&range.end);
1473            }
1474            let mut end_region = cursor.region().expect("end offset out of bounds");
1475            if !end_region.is_main_buffer {
1476                cursor.prev();
1477                if let Some(region) = cursor.region() {
1478                    end_region = region;
1479                } else {
1480                    continue;
1481                }
1482            }
1483
1484            if range.start > end_region.range.end {
1485                continue;
1486            }
1487
1488            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1489            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1490            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1491                .min(start_region.buffer_range.end);
1492            let buffer_end =
1493                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1494
1495            if start_region.excerpt == end_region.excerpt {
1496                if start_region.buffer.capability == Capability::ReadWrite
1497                    && start_region.is_main_buffer
1498                {
1499                    buffer_edits
1500                        .entry(start_region.buffer.remote_id())
1501                        .or_default()
1502                        .push(BufferEdit {
1503                            range: buffer_start..buffer_end,
1504                            new_text,
1505                            is_insertion: true,
1506                            original_indent_column,
1507                        });
1508                }
1509            } else {
1510                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1511                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1512                if start_region.buffer.capability == Capability::ReadWrite
1513                    && start_region.is_main_buffer
1514                {
1515                    buffer_edits
1516                        .entry(start_region.buffer.remote_id())
1517                        .or_default()
1518                        .push(BufferEdit {
1519                            range: start_excerpt_range,
1520                            new_text: new_text.clone(),
1521                            is_insertion: true,
1522                            original_indent_column,
1523                        });
1524                }
1525                if end_region.buffer.capability == Capability::ReadWrite
1526                    && end_region.is_main_buffer
1527                {
1528                    buffer_edits
1529                        .entry(end_region.buffer.remote_id())
1530                        .or_default()
1531                        .push(BufferEdit {
1532                            range: end_excerpt_range,
1533                            new_text: new_text.clone(),
1534                            is_insertion: false,
1535                            original_indent_column,
1536                        });
1537                }
1538                let end_region_excerpt = end_region.excerpt.clone();
1539
1540                cursor.seek(&range.start);
1541                cursor.next_excerpt();
1542                while let Some(region) = cursor.region() {
1543                    if region.excerpt == &end_region_excerpt {
1544                        break;
1545                    }
1546                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1547                        buffer_edits
1548                            .entry(region.buffer.remote_id())
1549                            .or_default()
1550                            .push(BufferEdit {
1551                                range: region.buffer_range.clone(),
1552                                new_text: new_text.clone(),
1553                                is_insertion: false,
1554                                original_indent_column,
1555                            });
1556                    }
1557                    cursor.next_excerpt();
1558                }
1559            }
1560        }
1561        buffer_edits
1562    }
1563
1564    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1565    where
1566        I: IntoIterator<Item = Range<S>>,
1567        S: ToOffset,
1568    {
1569        if self.read_only() || self.buffers.is_empty() {
1570            return;
1571        }
1572        self.sync_mut(cx);
1573        let empty = Arc::<str>::from("");
1574        let edits = ranges
1575            .into_iter()
1576            .map(|range| {
1577                let mut range = range.start.to_offset(self.snapshot.get_mut())
1578                    ..range.end.to_offset(&self.snapshot.get_mut());
1579                if range.start > range.end {
1580                    mem::swap(&mut range.start, &mut range.end);
1581                }
1582                (range, empty.clone())
1583            })
1584            .collect::<Vec<_>>();
1585
1586        return autoindent_ranges_internal(self, edits, cx);
1587
1588        fn autoindent_ranges_internal(
1589            this: &mut MultiBuffer,
1590            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1591            cx: &mut Context<MultiBuffer>,
1592        ) {
1593            let buffer_edits =
1594                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1595
1596            let mut buffer_ids = Vec::new();
1597            for (buffer_id, mut edits) in buffer_edits {
1598                buffer_ids.push(buffer_id);
1599                edits.sort_unstable_by_key(|edit| edit.range.start);
1600
1601                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1602                for edit in edits {
1603                    if let Some(last_range) = ranges.last_mut()
1604                        && edit.range.start <= last_range.end
1605                    {
1606                        last_range.end = last_range.end.max(edit.range.end);
1607                        continue;
1608                    }
1609                    ranges.push(edit.range);
1610                }
1611
1612                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1613                    buffer.autoindent_ranges(ranges, cx);
1614                })
1615            }
1616
1617            cx.emit(Event::BuffersEdited { buffer_ids });
1618        }
1619    }
1620
1621    pub fn set_active_selections(
1622        &self,
1623        selections: &[Selection<Anchor>],
1624        line_mode: bool,
1625        cursor_shape: CursorShape,
1626        cx: &mut Context<Self>,
1627    ) {
1628        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1629            Default::default();
1630        let snapshot = self.read(cx);
1631        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(());
1632        for selection in selections {
1633            let Some(start) = snapshot.anchor_seek_target(selection.start) else {
1634                continue;
1635            };
1636            let Some(end) = snapshot.anchor_seek_target(selection.end) else {
1637                continue;
1638            };
1639
1640            cursor.seek(&start, Bias::Left);
1641            while let Some(excerpt) = cursor.item()
1642                && sum_tree::SeekTarget::cmp(&end, &cursor.position, ()).is_gt()
1643            {
1644                let start = text::Anchor::max(
1645                    &excerpt.range.context.start,
1646                    &selection.start.text_anchor().unwrap_or(text::Anchor::MIN),
1647                    &excerpt.buffer,
1648                )
1649                .clone();
1650                let end = text::Anchor::min(
1651                    &excerpt.range.context.end,
1652                    &selection.end.text_anchor().unwrap_or(text::Anchor::MAX),
1653                    &excerpt.buffer,
1654                )
1655                .clone();
1656                selections_by_buffer
1657                    .entry(excerpt.buffer.remote_id())
1658                    .or_default()
1659                    .push(Selection {
1660                        id: selection.id,
1661                        start,
1662                        end,
1663                        reversed: selection.reversed,
1664                        goal: selection.goal,
1665                    });
1666
1667                cursor.next();
1668            }
1669        }
1670
1671        for (buffer_id, buffer_state) in self.buffers.iter() {
1672            if !selections_by_buffer.contains_key(buffer_id) {
1673                buffer_state
1674                    .buffer
1675                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1676            }
1677        }
1678
1679        for (buffer_id, selections) in selections_by_buffer {
1680            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1681                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1682            });
1683        }
1684    }
1685
1686    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1687        for buffer in self.buffers.values() {
1688            buffer
1689                .buffer
1690                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1691        }
1692    }
1693
1694    #[instrument(skip_all)]
1695    fn merge_excerpt_ranges<'a>(
1696        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1697    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1698        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1699        let mut counts: Vec<usize> = Vec::new();
1700        for range in expanded_ranges {
1701            if let Some(last_range) = merged_ranges.last_mut() {
1702                assert!(
1703                    last_range.context.start <= range.context.start,
1704                    "ranges must be sorted: {last_range:?} <= {range:?}"
1705                );
1706                if last_range.context.end >= range.context.start
1707                    || last_range.context.end.row + 1 == range.context.start.row
1708                {
1709                    last_range.context.end = range.context.end.max(last_range.context.end);
1710                    *counts.last_mut().unwrap() += 1;
1711                    continue;
1712                }
1713            }
1714            merged_ranges.push(range.clone());
1715            counts.push(1);
1716        }
1717        (merged_ranges, counts)
1718    }
1719
1720    pub fn clear(&mut self, cx: &mut Context<Self>) {
1721        self.sync_mut(cx);
1722        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1723        let MultiBufferSnapshot {
1724            excerpts,
1725            diffs: _,
1726            diff_transforms: _,
1727            non_text_state_update_count: _,
1728            edit_count: _,
1729            is_dirty,
1730            has_deleted_file,
1731            has_conflict,
1732            has_inverted_diff,
1733            singleton: _,
1734            trailing_excerpt_update_count,
1735            all_diff_hunks_expanded: _,
1736            show_deleted_hunks: _,
1737            use_extended_diff_range: _,
1738            show_headers: _,
1739            path_keys_by_buffer: _,
1740        } = self.snapshot.get_mut();
1741        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1742        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1743        *excerpts = Default::default();
1744        *trailing_excerpt_update_count += 1;
1745        *is_dirty = false;
1746        *has_deleted_file = false;
1747        *has_conflict = false;
1748        *has_inverted_diff = false;
1749
1750        let edits = Self::sync_diff_transforms(
1751            self.snapshot.get_mut(),
1752            vec![Edit {
1753                old: start..prev_len,
1754                new: start..start,
1755            }],
1756            DiffChangeKind::BufferEdited,
1757        );
1758        if !edits.is_empty() {
1759            self.subscriptions.publish(edits);
1760        }
1761        cx.emit(Event::Edited {
1762            edited_buffer: None,
1763        });
1764        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1765        cx.notify();
1766    }
1767
1768    #[ztracing::instrument(skip_all)]
1769    pub fn excerpts_for_buffer(
1770        &self,
1771        buffer_id: BufferId,
1772        cx: &App,
1773    ) -> Vec<ExcerptRange<text::Anchor>> {
1774        let mut excerpts = Vec::new();
1775        let snapshot = self.read(cx);
1776        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id).cloned() else {
1777            return excerpts;
1778        };
1779
1780        let mut cursor = snapshot.excerpts.cursor::<PathKey>(());
1781        cursor.seek_forward(&path_key, Bias::Left);
1782
1783        while let Some(item) = cursor.item()
1784            && item.path_key == path_key
1785        {
1786            excerpts.push(item.range.clone());
1787            cursor.next()
1788        }
1789        excerpts
1790    }
1791
1792    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1793        let snapshot = self.read(cx);
1794        let mut excerpts = snapshot
1795            .excerpts
1796            .cursor::<Dimensions<PathKey, ExcerptPoint>>(());
1797        let mut diff_transforms = snapshot
1798            .diff_transforms
1799            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1800        diff_transforms.next();
1801        let mut result = Vec::new();
1802        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id) else {
1803            return result;
1804        };
1805
1806        while let Some(excerpt) = excerpts.item()
1807            && &excerpt.path_key == path_key
1808        {
1809            let excerpt_start = excerpts.start().1;
1810            let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1811
1812            diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1813            let overshoot = excerpt_start - diff_transforms.start().0;
1814            let start = diff_transforms.start().1 + overshoot;
1815
1816            diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1817            let overshoot = excerpt_end - diff_transforms.start().0;
1818            let end = diff_transforms.start().1 + overshoot;
1819
1820            result.push(start.0..end.0);
1821            excerpts.next()
1822        }
1823        result
1824    }
1825
1826    // todo!() this seems bogus
1827    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1828        self.snapshot
1829            .borrow()
1830            .excerpts
1831            .iter()
1832            .map(|entry| entry.buffer.remote_id())
1833            .collect()
1834    }
1835
1836    pub fn excerpt_containing(&self, position: impl ToOffset, cx: &App) -> Option<ExcerptInfo> {
1837        let snapshot = self.read(cx);
1838        let offset = position.to_offset(&snapshot);
1839
1840        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1841        cursor.seek(&offset);
1842        let excerpt = cursor.excerpt().or(snapshot.excerpts.last())?;
1843        Some(ExcerptInfo {
1844            path_key: excerpt.path_key.clone(),
1845            buffer_id: excerpt.buffer.remote_id(),
1846            range: excerpt.range.clone(),
1847        })
1848    }
1849
1850    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1851        let buffer_id = match anchor {
1852            Anchor::Min => self.snapshot(cx).excerpts.first()?.buffer.remote_id(),
1853            Anchor::Max => self.snapshot(cx).excerpts.last()?.buffer.remote_id(),
1854            Anchor::Text { buffer_id, .. } => buffer_id,
1855        };
1856        self.buffer(buffer_id)
1857    }
1858
1859    // If point is at the end of the buffer, the last excerpt is returned
1860    pub fn point_to_buffer_offset<T: ToOffset>(
1861        &self,
1862        point: T,
1863        cx: &App,
1864    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1865        let snapshot = self.read(cx);
1866        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1867        Some((
1868            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1869            offset,
1870        ))
1871    }
1872
1873    // If point is at the end of the buffer, the last excerpt is returned
1874    pub fn point_to_buffer_point<T: ToPoint>(
1875        &self,
1876        point: T,
1877        cx: &App,
1878    ) -> Option<(Entity<Buffer>, Point)> {
1879        let snapshot = self.read(cx);
1880        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1881        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1882    }
1883
1884    pub fn buffer_point_to_anchor(
1885        &self,
1886        // todo(lw): We shouldn't need this?
1887        buffer: &Entity<Buffer>,
1888        point: Point,
1889        cx: &App,
1890    ) -> Option<Anchor> {
1891        let mut found = None;
1892        let snapshot = buffer.read(cx).snapshot();
1893        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1894            let start = range.context.start.to_point(&snapshot);
1895            let end = range.context.end.to_point(&snapshot);
1896            if start <= point && point < end {
1897                found = Some(snapshot.clip_point(point, Bias::Left));
1898                break;
1899            }
1900            if point < start {
1901                found = Some(start);
1902            }
1903            if point > end {
1904                found = Some(end);
1905            }
1906        }
1907
1908        Some(Anchor::text(snapshot.anchor_after(found?)))
1909    }
1910
1911    pub fn buffer_anchor_to_anchor(
1912        &self,
1913        // todo(lw): We shouldn't need this?
1914        buffer: &Entity<Buffer>,
1915        anchor: text::Anchor,
1916        cx: &App,
1917    ) -> Option<Anchor> {
1918        let snapshot = buffer.read(cx).snapshot();
1919        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1920            if range.contains(&anchor, &snapshot) {
1921                return Some(Anchor::text(anchor));
1922            }
1923        }
1924
1925        None
1926    }
1927
1928    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1929        &self,
1930        anchors: Anchors,
1931        cx: &mut Context<Self>,
1932    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1933        let mut error = None;
1934        let mut futures = Vec::new();
1935        for anchor in anchors {
1936            if let Some(text_anchor) = anchor.text_anchor() {
1937                if let Some(buffer) = self.buffers.get(&text_anchor.buffer_id.unwrap()) {
1938                    buffer.buffer.update(cx, |buffer, _| {
1939                        futures.push(buffer.wait_for_anchors([text_anchor]))
1940                    });
1941                } else {
1942                    error = Some(anyhow!(
1943                        "buffer {:?} is not part of this multi-buffer",
1944                        text_anchor.buffer_id
1945                    ));
1946                    break;
1947                }
1948            }
1949        }
1950        async move {
1951            if let Some(error) = error {
1952                Err(error)?;
1953            }
1954            for future in futures {
1955                future.await?;
1956            }
1957            Ok(())
1958        }
1959    }
1960
1961    pub fn text_anchor_for_position<T: ToOffset>(
1962        &self,
1963        position: T,
1964        cx: &App,
1965    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1966        let snapshot = self.read(cx);
1967        let anchor = snapshot.anchor_before(position).text_anchor()?;
1968        let buffer = self.buffers.get(&anchor.buffer_id.unwrap())?.buffer.clone();
1969        Some((buffer, anchor))
1970    }
1971
1972    fn on_buffer_event(
1973        &mut self,
1974        buffer: Entity<Buffer>,
1975        event: &language::BufferEvent,
1976        cx: &mut Context<Self>,
1977    ) {
1978        use language::BufferEvent;
1979        let buffer_id = buffer.read(cx).remote_id();
1980        cx.emit(match event {
1981            BufferEvent::Edited => Event::Edited {
1982                edited_buffer: Some(buffer),
1983            },
1984            BufferEvent::DirtyChanged => Event::DirtyChanged,
1985            BufferEvent::Saved => Event::Saved,
1986            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1987            BufferEvent::Reloaded => Event::Reloaded,
1988            BufferEvent::LanguageChanged(has_language) => {
1989                Event::LanguageChanged(buffer_id, *has_language)
1990            }
1991            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1992            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1993            BufferEvent::CapabilityChanged => {
1994                self.capability = buffer.read(cx).capability();
1995                return;
1996            }
1997            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1998        });
1999    }
2000
2001    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2002        let diff = diff.read(cx);
2003        let buffer_id = diff.buffer_id;
2004        let diff = DiffStateSnapshot {
2005            diff: diff.snapshot(cx),
2006            main_buffer: None,
2007        };
2008        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2009    }
2010
2011    fn inverted_buffer_diff_language_changed(
2012        &mut self,
2013        diff: Entity<BufferDiff>,
2014        main_buffer: Entity<language::Buffer>,
2015        cx: &mut Context<Self>,
2016    ) {
2017        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2018        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2019        let diff = diff.read(cx);
2020        let diff = DiffStateSnapshot {
2021            diff: diff.snapshot(cx),
2022            main_buffer: Some(main_buffer_snapshot),
2023        };
2024        self.snapshot
2025            .get_mut()
2026            .diffs
2027            .insert(base_text_buffer_id, diff);
2028    }
2029
2030    fn buffer_diff_changed(
2031        &mut self,
2032        diff: Entity<BufferDiff>,
2033        range: Range<text::Anchor>,
2034        cx: &mut Context<Self>,
2035    ) {
2036        self.sync_mut(cx);
2037
2038        let diff = diff.read(cx);
2039        let buffer_id = diff.buffer_id;
2040
2041        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2042            return;
2043        };
2044        let new_diff = DiffStateSnapshot {
2045            diff: diff.snapshot(cx),
2046            main_buffer: None,
2047        };
2048        let mut snapshot = self.snapshot.get_mut();
2049        let base_text_changed = snapshot
2050            .diffs
2051            .get(&buffer_id)
2052            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2053        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2054
2055        let buffer = buffer_state.buffer.read(cx);
2056        let diff_change_range = range.to_offset(buffer);
2057
2058        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2059        let edits = Self::sync_diff_transforms(
2060            &mut snapshot,
2061            excerpt_edits,
2062            DiffChangeKind::DiffUpdated {
2063                base_changed: base_text_changed,
2064            },
2065        );
2066        if !edits.is_empty() {
2067            self.subscriptions.publish(edits);
2068        }
2069        cx.emit(Event::Edited {
2070            edited_buffer: None,
2071        });
2072    }
2073
2074    fn inverted_buffer_diff_changed(
2075        &mut self,
2076        diff: Entity<BufferDiff>,
2077        main_buffer: Entity<language::Buffer>,
2078        diff_change_range: Option<Range<usize>>,
2079        cx: &mut Context<Self>,
2080    ) {
2081        self.sync_mut(cx);
2082
2083        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2084        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2085            return;
2086        };
2087
2088        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2089        let diff = diff.read(cx);
2090        let new_diff = DiffStateSnapshot {
2091            diff: diff.snapshot(cx),
2092            main_buffer: Some(main_buffer_snapshot),
2093        };
2094        let mut snapshot = self.snapshot.get_mut();
2095        snapshot
2096            .diffs
2097            .insert_or_replace(base_text_buffer_id, new_diff);
2098
2099        let Some(diff_change_range) = diff_change_range else {
2100            return;
2101        };
2102
2103        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2104        let edits = Self::sync_diff_transforms(
2105            &mut snapshot,
2106            excerpt_edits,
2107            DiffChangeKind::DiffUpdated {
2108                // We don't read this field for inverted diffs.
2109                base_changed: false,
2110            },
2111        );
2112        if !edits.is_empty() {
2113            self.subscriptions.publish(edits);
2114        }
2115        cx.emit(Event::Edited {
2116            edited_buffer: None,
2117        });
2118    }
2119
2120    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2121        self.buffers.values().map(|state| state.buffer.clone())
2122    }
2123
2124    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2125        self.all_buffers_iter().collect()
2126    }
2127
2128    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2129        self.buffers.keys().copied()
2130    }
2131
2132    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2133        self.all_buffer_ids_iter().collect()
2134    }
2135
2136    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2137        self.buffers
2138            .get(&buffer_id)
2139            .map(|state| state.buffer.clone())
2140    }
2141
2142    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2143        self.point_to_buffer_offset(point, cx)
2144            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2145    }
2146
2147    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2148        let buffer_id = self
2149            .snapshot
2150            .borrow()
2151            .excerpts
2152            .first()
2153            .map(|excerpt| excerpt.buffer.remote_id());
2154        buffer_id
2155            .and_then(|buffer_id| self.buffer(buffer_id))
2156            .map(|buffer| {
2157                let buffer = buffer.read(cx);
2158                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2159            })
2160            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2161    }
2162
2163    pub fn language_settings_at<'a, T: ToOffset>(
2164        &'a self,
2165        point: T,
2166        cx: &'a App,
2167    ) -> Cow<'a, LanguageSettings> {
2168        let mut language = None;
2169        let mut file = None;
2170        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2171            let buffer = buffer.read(cx);
2172            language = buffer.language_at(offset);
2173            file = buffer.file();
2174        }
2175        language_settings(language.map(|l| l.name()), file, cx)
2176    }
2177
2178    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2179        self.buffers.values().for_each(|state| f(&state.buffer))
2180    }
2181
2182    pub fn explicit_title(&self) -> Option<&str> {
2183        self.title.as_deref()
2184    }
2185
2186    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2187        if let Some(title) = self.title.as_ref() {
2188            return title.into();
2189        }
2190
2191        if let Some(buffer) = self.as_singleton() {
2192            let buffer = buffer.read(cx);
2193
2194            if let Some(file) = buffer.file() {
2195                return file.file_name(cx).into();
2196            }
2197
2198            if let Some(title) = self.buffer_content_title(buffer) {
2199                return title;
2200            }
2201        };
2202
2203        "untitled".into()
2204    }
2205
2206    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2207        let mut is_leading_whitespace = true;
2208        let mut count = 0;
2209        let mut prev_was_space = false;
2210        let mut title = String::new();
2211
2212        for ch in buffer.snapshot().chars() {
2213            if is_leading_whitespace && ch.is_whitespace() {
2214                continue;
2215            }
2216
2217            is_leading_whitespace = false;
2218
2219            if ch == '\n' || count >= 40 {
2220                break;
2221            }
2222
2223            if ch.is_whitespace() {
2224                if !prev_was_space {
2225                    title.push(' ');
2226                    count += 1;
2227                    prev_was_space = true;
2228                }
2229            } else {
2230                title.push(ch);
2231                count += 1;
2232                prev_was_space = false;
2233            }
2234        }
2235
2236        let title = title.trim_end().to_string();
2237
2238        if title.is_empty() {
2239            return None;
2240        }
2241
2242        Some(title.into())
2243    }
2244
2245    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2246        self.title = Some(title);
2247        cx.notify();
2248    }
2249
2250    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2251    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2252        for buffer_state in self.buffers.values() {
2253            buffer_state
2254                .buffer
2255                .update(cx, |buffer, _cx| buffer.refresh_preview());
2256        }
2257    }
2258
2259    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2260    pub fn preserve_preview(&self, cx: &App) -> bool {
2261        self.buffers
2262            .values()
2263            .all(|state| state.buffer.read(cx).preserve_preview())
2264    }
2265
2266    #[cfg(any(test, feature = "test-support"))]
2267    pub fn is_parsing(&self, cx: &App) -> bool {
2268        self.as_singleton().unwrap().read(cx).is_parsing()
2269    }
2270
2271    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2272        let buffer_id = diff.read(cx).buffer_id;
2273
2274        if let Some(existing_diff) = self.diff_for(buffer_id)
2275            && diff.entity_id() == existing_diff.entity_id()
2276        {
2277            return;
2278        }
2279
2280        self.buffer_diff_changed(
2281            diff.clone(),
2282            text::Anchor::min_max_range_for_buffer(buffer_id),
2283            cx,
2284        );
2285        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2286    }
2287
2288    pub fn add_inverted_diff(
2289        &mut self,
2290        diff: Entity<BufferDiff>,
2291        main_buffer: Entity<language::Buffer>,
2292        cx: &mut Context<Self>,
2293    ) {
2294        let snapshot = diff.read(cx).base_text(cx);
2295        let base_text_buffer_id = snapshot.remote_id();
2296        let diff_change_range = 0..snapshot.len();
2297        self.snapshot.get_mut().has_inverted_diff = true;
2298        self.inverted_buffer_diff_changed(
2299            diff.clone(),
2300            main_buffer.clone(),
2301            Some(diff_change_range),
2302            cx,
2303        );
2304        self.diffs.insert(
2305            base_text_buffer_id,
2306            DiffState::new_inverted(diff, main_buffer, cx),
2307        );
2308    }
2309
2310    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2311        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2312    }
2313
2314    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2315        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2316    }
2317
2318    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2319        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2320    }
2321
2322    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2323        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2324        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2325    }
2326
2327    pub fn all_diff_hunks_expanded(&self) -> bool {
2328        self.snapshot.borrow().all_diff_hunks_expanded
2329    }
2330
2331    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2332        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2333        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2334    }
2335
2336    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2337        self.snapshot.get_mut().show_deleted_hunks = show;
2338
2339        self.sync_mut(cx);
2340
2341        let old_len = self.snapshot.borrow().len();
2342
2343        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2344        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2345
2346        let new_len = self.snapshot.borrow().len();
2347
2348        self.subscriptions.publish(vec![Edit {
2349            old: MultiBufferOffset(0)..old_len,
2350            new: MultiBufferOffset(0)..new_len,
2351        }]);
2352
2353        cx.emit(Event::DiffHunksToggled);
2354        cx.emit(Event::Edited {
2355            edited_buffer: None,
2356        });
2357    }
2358
2359    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2360        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2361    }
2362
2363    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2364        self.read(cx)
2365            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2366            .nth(1)
2367            .is_some()
2368    }
2369
2370    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2371        let snapshot = self.read(cx);
2372        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2373        let offset_range = range.to_offset(&snapshot);
2374        cursor.seek(&offset_range.start, Bias::Left);
2375        while let Some(item) = cursor.item() {
2376            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2377                break;
2378            }
2379            if item.hunk_info().is_some() {
2380                return true;
2381            }
2382            cursor.next();
2383        }
2384        false
2385    }
2386
2387    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2388        let snapshot = self.read(cx);
2389        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2390        for range in ranges {
2391            let range = range.to_point(&snapshot);
2392            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2393            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2394                .min(snapshot.len());
2395            cursor.seek(&start, Bias::Right);
2396            while let Some(item) = cursor.item() {
2397                if *cursor.start() >= end {
2398                    break;
2399                }
2400                if item.hunk_info().is_some() {
2401                    return true;
2402                }
2403                cursor.next();
2404            }
2405        }
2406        false
2407    }
2408
2409    pub fn expand_or_collapse_diff_hunks_inner(
2410        &mut self,
2411        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2412        expand: bool,
2413        cx: &mut Context<Self>,
2414    ) -> Vec<Edit<MultiBufferOffset>> {
2415        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2416            return Vec::new();
2417        }
2418        self.sync_mut(cx);
2419        let mut snapshot = self.snapshot.get_mut();
2420        let mut excerpt_edits = Vec::new();
2421        let mut last_hunk_row = None;
2422        for (range, end_excerpt_id) in ranges {
2423            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2424                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2425                    continue;
2426                }
2427                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2428                    continue;
2429                }
2430                let start = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2431                let end = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2432                let start = snapshot.excerpt_offset_for_anchor(&start);
2433                let end = snapshot.excerpt_offset_for_anchor(&end);
2434                last_hunk_row = Some(diff_hunk.row_range.start);
2435                excerpt_edits.push(text::Edit {
2436                    old: start..end,
2437                    new: start..end,
2438                });
2439            }
2440        }
2441
2442        Self::sync_diff_transforms(
2443            &mut snapshot,
2444            excerpt_edits,
2445            DiffChangeKind::ExpandOrCollapseHunks { expand },
2446        )
2447    }
2448
2449    pub fn expand_or_collapse_diff_hunks(
2450        &mut self,
2451        ranges: Vec<Range<Anchor>>,
2452        expand: bool,
2453        cx: &mut Context<Self>,
2454    ) {
2455        let snapshot = self.snapshot.borrow().clone();
2456        let ranges = ranges.iter().map(move |range| {
2457            let end_excerpt_id = range.end.excerpt_id;
2458            let range = range.to_point(&snapshot);
2459            let mut peek_end = range.end;
2460            if range.end.row < snapshot.max_row().0 {
2461                peek_end = Point::new(range.end.row + 1, 0);
2462            };
2463            (range.start..peek_end, end_excerpt_id)
2464        });
2465        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2466        if !edits.is_empty() {
2467            self.subscriptions.publish(edits);
2468        }
2469        cx.emit(Event::DiffHunksToggled);
2470        cx.emit(Event::Edited {
2471            edited_buffer: None,
2472        });
2473    }
2474
2475    pub fn resize_excerpt(
2476        &mut self,
2477        id: ExcerptId,
2478        range: Range<text::Anchor>,
2479        cx: &mut Context<Self>,
2480    ) {
2481        self.sync_mut(cx);
2482
2483        let mut snapshot = self.snapshot.get_mut();
2484        let locator = snapshot.excerpt_locator_for_id(id);
2485        let mut new_excerpts = SumTree::default();
2486        let mut cursor = snapshot
2487            .excerpts
2488            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2489        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2490
2491        let prefix = cursor.slice(&Some(locator), Bias::Left);
2492        new_excerpts.append(prefix, ());
2493
2494        let mut excerpt = cursor.item().unwrap().clone();
2495        let old_text_len = excerpt.text_summary.len;
2496
2497        excerpt.range.context.start = range.start;
2498        excerpt.range.context.end = range.end;
2499        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2500
2501        excerpt.text_summary = excerpt
2502            .buffer
2503            .text_summary_for_range(excerpt.range.context.clone());
2504
2505        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2506        let old_start_offset = cursor.start().1;
2507        let new_text_len = excerpt.text_summary.len;
2508        let edit = Edit {
2509            old: old_start_offset..old_start_offset + old_text_len,
2510            new: new_start_offset..new_start_offset + new_text_len,
2511        };
2512
2513        if let Some(last_edit) = edits.last_mut() {
2514            if last_edit.old.end == edit.old.start {
2515                last_edit.old.end = edit.old.end;
2516                last_edit.new.end = edit.new.end;
2517            } else {
2518                edits.push(edit);
2519            }
2520        } else {
2521            edits.push(edit);
2522        }
2523
2524        new_excerpts.push(excerpt, ());
2525
2526        cursor.next();
2527
2528        new_excerpts.append(cursor.suffix(), ());
2529
2530        drop(cursor);
2531        snapshot.excerpts = new_excerpts;
2532
2533        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2534        if !edits.is_empty() {
2535            self.subscriptions.publish(edits);
2536        }
2537        cx.emit(Event::Edited {
2538            edited_buffer: None,
2539        });
2540        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2541        cx.notify();
2542    }
2543
2544    pub fn expand_excerpts(
2545        &mut self,
2546        ids: impl IntoIterator<Item = ExcerptId>,
2547        line_count: u32,
2548        direction: ExpandExcerptDirection,
2549        cx: &mut Context<Self>,
2550    ) {
2551        if line_count == 0 {
2552            return;
2553        }
2554        self.sync_mut(cx);
2555        if !self.excerpts_by_path.is_empty() {
2556            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2557            return;
2558        }
2559        let mut snapshot = self.snapshot.get_mut();
2560
2561        let ids = ids.into_iter().collect::<Vec<_>>();
2562        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2563        let mut new_excerpts = SumTree::default();
2564        let mut cursor = snapshot
2565            .excerpts
2566            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2567        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2568
2569        for locator in &locators {
2570            let prefix = cursor.slice(&Some(locator), Bias::Left);
2571            new_excerpts.append(prefix, ());
2572
2573            let mut excerpt = cursor.item().unwrap().clone();
2574            let old_text_len = excerpt.text_summary.len;
2575
2576            let up_line_count = if direction.should_expand_up() {
2577                line_count
2578            } else {
2579                0
2580            };
2581
2582            let start_row = excerpt
2583                .range
2584                .context
2585                .start
2586                .to_point(&excerpt.buffer)
2587                .row
2588                .saturating_sub(up_line_count);
2589            let start_point = Point::new(start_row, 0);
2590            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2591
2592            let down_line_count = if direction.should_expand_down() {
2593                line_count
2594            } else {
2595                0
2596            };
2597
2598            let mut end_point = excerpt.buffer.clip_point(
2599                excerpt.range.context.end.to_point(&excerpt.buffer)
2600                    + Point::new(down_line_count, 0),
2601                Bias::Left,
2602            );
2603            end_point.column = excerpt.buffer.line_len(end_point.row);
2604            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2605            excerpt.max_buffer_row = end_point.row;
2606
2607            excerpt.text_summary = excerpt
2608                .buffer
2609                .text_summary_for_range(excerpt.range.context.clone());
2610
2611            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2612            let old_start_offset = cursor.start().1;
2613            let new_text_len = excerpt.text_summary.len;
2614            let edit = Edit {
2615                old: old_start_offset..old_start_offset + old_text_len,
2616                new: new_start_offset..new_start_offset + new_text_len,
2617            };
2618
2619            if let Some(last_edit) = edits.last_mut() {
2620                if last_edit.old.end == edit.old.start {
2621                    last_edit.old.end = edit.old.end;
2622                    last_edit.new.end = edit.new.end;
2623                } else {
2624                    edits.push(edit);
2625                }
2626            } else {
2627                edits.push(edit);
2628            }
2629
2630            new_excerpts.push(excerpt, ());
2631
2632            cursor.next();
2633        }
2634
2635        new_excerpts.append(cursor.suffix(), ());
2636
2637        drop(cursor);
2638        snapshot.excerpts = new_excerpts;
2639
2640        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2641        if !edits.is_empty() {
2642            self.subscriptions.publish(edits);
2643        }
2644        cx.emit(Event::Edited {
2645            edited_buffer: None,
2646        });
2647        cx.emit(Event::ExcerptsExpanded { ids });
2648        cx.notify();
2649    }
2650
2651    #[ztracing::instrument(skip_all)]
2652    fn sync(&self, cx: &App) {
2653        let changed = self.buffer_changed_since_sync.replace(false);
2654        if !changed {
2655            return;
2656        }
2657        let edits = Self::sync_from_buffer_changes(
2658            &mut self.snapshot.borrow_mut(),
2659            &self.buffers,
2660            &self.diffs,
2661            cx,
2662        );
2663        if !edits.is_empty() {
2664            self.subscriptions.publish(edits);
2665        }
2666    }
2667
2668    fn sync_mut(&mut self, cx: &App) {
2669        let changed = self.buffer_changed_since_sync.replace(false);
2670        if !changed {
2671            return;
2672        }
2673        let edits =
2674            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2675
2676        if !edits.is_empty() {
2677            self.subscriptions.publish(edits);
2678        }
2679    }
2680
2681    fn sync_from_buffer_changes(
2682        snapshot: &mut MultiBufferSnapshot,
2683        buffers: &BTreeMap<BufferId, BufferState>,
2684        diffs: &HashMap<BufferId, DiffState>,
2685        cx: &App,
2686    ) -> Vec<Edit<MultiBufferOffset>> {
2687        let MultiBufferSnapshot {
2688            excerpts,
2689            buffer_paths: _,
2690            diffs: buffer_diff,
2691            diff_transforms: _,
2692            non_text_state_update_count,
2693            edit_count,
2694            is_dirty,
2695            has_deleted_file,
2696            has_conflict,
2697            has_inverted_diff: _,
2698            singleton: _,
2699            trailing_excerpt_update_count: _,
2700            all_diff_hunks_expanded: _,
2701            show_deleted_hunks: _,
2702            use_extended_diff_range: _,
2703            show_headers: _,
2704        } = snapshot;
2705        *is_dirty = false;
2706        *has_deleted_file = false;
2707        *has_conflict = false;
2708
2709        if !diffs.is_empty() {
2710            let mut diffs_to_add = Vec::new();
2711            for (id, diff) in diffs {
2712                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2713                // and use the diff hunk base text ranges to compute diff transforms.
2714                // Those base text ranges are usize, so make sure if the base text changed
2715                // we also update the diff snapshot so that we don't use stale offsets
2716                if buffer_diff.get(id).is_none_or(|existing_diff| {
2717                    if existing_diff.main_buffer.is_none() {
2718                        return false;
2719                    }
2720                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2721                    base_text.remote_id() != existing_diff.base_text().remote_id()
2722                        || base_text
2723                            .version()
2724                            .changed_since(existing_diff.base_text().version())
2725                }) {
2726                    if diffs_to_add.capacity() == 0 {
2727                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2728                        // meaning re-allocations will be fairly expensive
2729                        diffs_to_add.reserve(diffs.len());
2730                    }
2731                    diffs_to_add.push((*id, diff.snapshot(cx)));
2732                }
2733            }
2734            buffer_diff.extend(diffs_to_add);
2735        }
2736
2737        let mut excerpts_to_edit = Vec::new();
2738        let mut non_text_state_updated = false;
2739        let mut edited = false;
2740        for buffer_state in buffers.values() {
2741            let buffer = buffer_state.buffer.read(cx);
2742            let version = buffer.version();
2743            let non_text_state_update_count = buffer.non_text_state_update_count();
2744
2745            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2746            let buffer_non_text_state_updated =
2747                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2748            if buffer_edited || buffer_non_text_state_updated {
2749                *buffer_state.last_version.borrow_mut() = version;
2750                buffer_state
2751                    .last_non_text_state_update_count
2752                    .set(non_text_state_update_count);
2753                excerpts_to_edit.extend(
2754                    buffer_state
2755                        .excerpts
2756                        .iter()
2757                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2758                );
2759            }
2760
2761            edited |= buffer_edited;
2762            non_text_state_updated |= buffer_non_text_state_updated;
2763            *is_dirty |= buffer.is_dirty();
2764            *has_deleted_file |= buffer
2765                .file()
2766                .is_some_and(|file| file.disk_state().is_deleted());
2767            *has_conflict |= buffer.has_conflict();
2768        }
2769        if edited {
2770            *edit_count += 1;
2771        }
2772        if non_text_state_updated {
2773            *non_text_state_update_count += 1;
2774        }
2775
2776        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
2777
2778        let mut edits = Vec::new();
2779        let mut new_excerpts = SumTree::default();
2780        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2781
2782        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2783            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2784            let old_excerpt = cursor.item().unwrap();
2785            let buffer = buffer.read(cx);
2786            let buffer_id = buffer.remote_id();
2787            let mut new_excerpt;
2788            if buffer_edited {
2789                edits.extend(
2790                    buffer
2791                        .edits_since_in_range::<usize>(
2792                            old_excerpt.buffer.version(),
2793                            old_excerpt.range.context.clone(),
2794                        )
2795                        .map(|edit| {
2796                            let excerpt_old_start = cursor.start().1;
2797                            let excerpt_new_start =
2798                                ExcerptDimension(new_excerpts.summary().text.len);
2799                            let old_start = excerpt_old_start + edit.old.start;
2800                            let old_end = excerpt_old_start + edit.old.end;
2801                            let new_start = excerpt_new_start + edit.new.start;
2802                            let new_end = excerpt_new_start + edit.new.end;
2803                            Edit {
2804                                old: old_start..old_end,
2805                                new: new_start..new_end,
2806                            }
2807                        }),
2808                );
2809
2810                new_excerpt = Excerpt::new(
2811                    old_excerpt.id,
2812                    locator.clone(),
2813                    buffer_id,
2814                    Arc::new(buffer.snapshot()),
2815                    old_excerpt.range.clone(),
2816                    old_excerpt.has_trailing_newline,
2817                );
2818            } else {
2819                new_excerpt = old_excerpt.clone();
2820                new_excerpt.buffer = Arc::new(buffer.snapshot());
2821            }
2822
2823            new_excerpts.push(new_excerpt, ());
2824            cursor.next();
2825        }
2826        new_excerpts.append(cursor.suffix(), ());
2827
2828        drop(cursor);
2829        *excerpts = new_excerpts;
2830
2831        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2832    }
2833
2834    fn sync_diff_transforms(
2835        snapshot: &mut MultiBufferSnapshot,
2836        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2837        change_kind: DiffChangeKind,
2838    ) -> Vec<Edit<MultiBufferOffset>> {
2839        if excerpt_edits.is_empty() {
2840            return vec![];
2841        }
2842
2843        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2844        let mut old_diff_transforms = snapshot
2845            .diff_transforms
2846            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2847        let mut new_diff_transforms = SumTree::default();
2848        let mut old_expanded_hunks = HashSet::default();
2849        let mut output_edits = Vec::new();
2850        let mut output_delta = 0_isize;
2851        let mut at_transform_boundary = true;
2852        let mut end_of_current_insert = None;
2853
2854        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2855        while let Some(edit) = excerpt_edits.next() {
2856            excerpts.seek_forward(&edit.new.start, Bias::Right);
2857            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2858                excerpts.prev();
2859            }
2860
2861            // Keep any transforms that are before the edit.
2862            if at_transform_boundary {
2863                at_transform_boundary = false;
2864                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2865                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2866                if let Some(transform) = old_diff_transforms.item()
2867                    && old_diff_transforms.end().0 == edit.old.start
2868                    && old_diff_transforms.start().0 < edit.old.start
2869                {
2870                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2871                    old_diff_transforms.next();
2872                }
2873            }
2874
2875            // Compute the start of the edit in output coordinates.
2876            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2877            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2878            let edit_new_start =
2879                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2880
2881            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2882                &edit,
2883                &mut excerpts,
2884                &mut old_diff_transforms,
2885                &mut new_diff_transforms,
2886                &mut end_of_current_insert,
2887                &mut old_expanded_hunks,
2888                snapshot,
2889                change_kind,
2890            );
2891
2892            // Compute the end of the edit in output coordinates.
2893            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2894            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2895            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2896            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2897            let output_edit = Edit {
2898                old: edit_old_start..edit_old_end,
2899                new: edit_new_start..edit_new_end,
2900            };
2901
2902            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2903            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2904            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2905                output_edits.push(output_edit);
2906            }
2907
2908            // If this is the last edit that intersects the current diff transform,
2909            // then recreate the content up to the end of this transform, to prepare
2910            // for reusing additional slices of the old transforms.
2911            if excerpt_edits
2912                .peek()
2913                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2914            {
2915                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2916                    && match old_diff_transforms.item() {
2917                        Some(DiffTransform::BufferContent {
2918                            inserted_hunk_info: Some(hunk),
2919                            ..
2920                        }) => excerpts.item().is_some_and(|excerpt| {
2921                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2922                                && diff.main_buffer.is_some()
2923                            {
2924                                return true;
2925                            }
2926                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2927                        }),
2928                        _ => true,
2929                    };
2930
2931                let mut excerpt_offset = edit.new.end;
2932                if !keep_next_old_transform {
2933                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2934                    old_diff_transforms.next();
2935                }
2936
2937                old_expanded_hunks.clear();
2938                Self::push_buffer_content_transform(
2939                    snapshot,
2940                    &mut new_diff_transforms,
2941                    excerpt_offset,
2942                    end_of_current_insert,
2943                );
2944                at_transform_boundary = true;
2945            }
2946        }
2947
2948        // Keep any transforms that are after the last edit.
2949        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2950
2951        // Ensure there's always at least one buffer content transform.
2952        if new_diff_transforms.is_empty() {
2953            new_diff_transforms.push(
2954                DiffTransform::BufferContent {
2955                    summary: Default::default(),
2956                    inserted_hunk_info: None,
2957                },
2958                (),
2959            );
2960        }
2961
2962        drop(old_diff_transforms);
2963        drop(excerpts);
2964        snapshot.diff_transforms = new_diff_transforms;
2965        snapshot.edit_count += 1;
2966
2967        #[cfg(any(test, feature = "test-support"))]
2968        snapshot.check_invariants();
2969        output_edits
2970    }
2971
2972    fn recompute_diff_transforms_for_edit(
2973        edit: &Edit<ExcerptOffset>,
2974        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2975        old_diff_transforms: &mut Cursor<
2976            DiffTransform,
2977            Dimensions<ExcerptOffset, MultiBufferOffset>,
2978        >,
2979        new_diff_transforms: &mut SumTree<DiffTransform>,
2980        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2981        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2982        snapshot: &MultiBufferSnapshot,
2983        change_kind: DiffChangeKind,
2984    ) -> bool {
2985        log::trace!(
2986            "recomputing diff transform for edit {:?} => {:?}",
2987            edit.old.start..edit.old.end,
2988            edit.new.start..edit.new.end
2989        );
2990
2991        // Record which hunks were previously expanded.
2992        while let Some(item) = old_diff_transforms.item() {
2993            if let Some(hunk_info) = item.hunk_info() {
2994                log::trace!(
2995                    "previously expanded hunk at {:?}",
2996                    old_diff_transforms.start()
2997                );
2998                old_expanded_hunks.insert(hunk_info);
2999            }
3000            if old_diff_transforms.end().0 > edit.old.end {
3001                break;
3002            }
3003            old_diff_transforms.next();
3004        }
3005
3006        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3007        // For inverted diffs, hunks are always shown, so we can't skip this.
3008        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3009        if old_expanded_hunks.is_empty()
3010            && change_kind == DiffChangeKind::BufferEdited
3011            && !all_diff_hunks_expanded
3012            && !snapshot.has_inverted_diff
3013        {
3014            return false;
3015        }
3016
3017        // Visit each excerpt that intersects the edit.
3018        let mut did_expand_hunks = false;
3019        while let Some(excerpt) = excerpts.item() {
3020            // Recompute the expanded hunks in the portion of the excerpt that
3021            // intersects the edit.
3022            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3023                let buffer = &excerpt.buffer;
3024                let excerpt_start = *excerpts.start();
3025                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3026                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3027                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3028                let edit_buffer_start =
3029                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3030                let edit_buffer_end =
3031                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3032                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3033
3034                if let Some(main_buffer) = &diff.main_buffer {
3035                    for hunk in diff.hunks_intersecting_base_text_range(
3036                        edit_buffer_start..edit_buffer_end,
3037                        main_buffer,
3038                    ) {
3039                        did_expand_hunks = true;
3040                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3041                        if hunk_buffer_range.start < excerpt_buffer_start {
3042                            log::trace!("skipping hunk that starts before excerpt");
3043                            continue;
3044                        }
3045                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3046                        let hunk_excerpt_start = excerpt_start
3047                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3048                        let hunk_excerpt_end = excerpt_end
3049                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3050                        Self::push_buffer_content_transform(
3051                            snapshot,
3052                            new_diff_transforms,
3053                            hunk_excerpt_start,
3054                            *end_of_current_insert,
3055                        );
3056                        if !hunk_buffer_range.is_empty() {
3057                            let hunk_info = DiffTransformHunkInfo {
3058                                excerpt_id: excerpt.id,
3059                                hunk_start_anchor: hunk.buffer_range.start,
3060                                hunk_secondary_status: hunk.secondary_status,
3061                                is_logically_deleted: true,
3062                            };
3063                            *end_of_current_insert =
3064                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3065                        }
3066                    }
3067                } else {
3068                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3069                        ..buffer.anchor_after(edit_buffer_end);
3070                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3071                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3072                            continue;
3073                        }
3074
3075                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3076                        if hunk_buffer_range.start < excerpt_buffer_start {
3077                            log::trace!("skipping hunk that starts before excerpt");
3078                            continue;
3079                        }
3080
3081                        let hunk_info = DiffTransformHunkInfo {
3082                            excerpt_id: excerpt.id,
3083                            hunk_start_anchor: hunk.buffer_range.start,
3084                            hunk_secondary_status: hunk.secondary_status,
3085                            is_logically_deleted: false,
3086                        };
3087
3088                        let hunk_excerpt_start = excerpt_start
3089                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3090                        let hunk_excerpt_end = excerpt_end
3091                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3092
3093                        Self::push_buffer_content_transform(
3094                            snapshot,
3095                            new_diff_transforms,
3096                            hunk_excerpt_start,
3097                            *end_of_current_insert,
3098                        );
3099
3100                        // For every existing hunk, determine if it was previously expanded
3101                        // and if it should currently be expanded.
3102                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3103                        let should_expand_hunk = match &change_kind {
3104                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3105                                was_previously_expanded || all_diff_hunks_expanded
3106                            }
3107                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3108                                let intersects = hunk_buffer_range.is_empty()
3109                                    || hunk_buffer_range.end > edit_buffer_start;
3110                                if *expand {
3111                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3112                                } else {
3113                                    !intersects
3114                                        && (was_previously_expanded || all_diff_hunks_expanded)
3115                                }
3116                            }
3117                            _ => was_previously_expanded || all_diff_hunks_expanded,
3118                        };
3119
3120                        if should_expand_hunk {
3121                            did_expand_hunks = true;
3122                            log::trace!(
3123                                "expanding hunk {:?}, excerpt:{:?}",
3124                                hunk_excerpt_start..hunk_excerpt_end,
3125                                excerpt.id
3126                            );
3127
3128                            if !hunk.diff_base_byte_range.is_empty()
3129                                && hunk_buffer_range.start >= edit_buffer_start
3130                                && hunk_buffer_range.start <= excerpt_buffer_end
3131                                && snapshot.show_deleted_hunks
3132                            {
3133                                let base_text = diff.base_text();
3134                                let mut text_cursor =
3135                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3136                                let mut base_text_summary = text_cursor
3137                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3138
3139                                let mut has_trailing_newline = false;
3140                                if base_text_summary.last_line_chars > 0 {
3141                                    base_text_summary += TextSummary::newline();
3142                                    has_trailing_newline = true;
3143                                }
3144
3145                                new_diff_transforms.push(
3146                                    DiffTransform::DeletedHunk {
3147                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3148                                        summary: base_text_summary,
3149                                        buffer_id: excerpt.buffer_id,
3150                                        hunk_info,
3151                                        has_trailing_newline,
3152                                    },
3153                                    (),
3154                                );
3155                            }
3156
3157                            if !hunk_buffer_range.is_empty() {
3158                                *end_of_current_insert =
3159                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3160                            }
3161                        }
3162                    }
3163                }
3164            }
3165
3166            if excerpts.end() <= edit.new.end {
3167                excerpts.next();
3168            } else {
3169                break;
3170            }
3171        }
3172
3173        did_expand_hunks || !old_expanded_hunks.is_empty()
3174    }
3175
3176    fn append_diff_transforms(
3177        new_transforms: &mut SumTree<DiffTransform>,
3178        subtree: SumTree<DiffTransform>,
3179    ) {
3180        if let Some(DiffTransform::BufferContent {
3181            inserted_hunk_info,
3182            summary,
3183        }) = subtree.first()
3184            && Self::extend_last_buffer_content_transform(
3185                new_transforms,
3186                *inserted_hunk_info,
3187                *summary,
3188            )
3189        {
3190            let mut cursor = subtree.cursor::<()>(());
3191            cursor.next();
3192            cursor.next();
3193            new_transforms.append(cursor.suffix(), ());
3194            return;
3195        }
3196        new_transforms.append(subtree, ());
3197    }
3198
3199    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3200        if let DiffTransform::BufferContent {
3201            inserted_hunk_info: inserted_hunk_anchor,
3202            summary,
3203        } = transform
3204            && Self::extend_last_buffer_content_transform(
3205                new_transforms,
3206                inserted_hunk_anchor,
3207                summary,
3208            )
3209        {
3210            return;
3211        }
3212        new_transforms.push(transform, ());
3213    }
3214
3215    fn push_buffer_content_transform(
3216        old_snapshot: &MultiBufferSnapshot,
3217        new_transforms: &mut SumTree<DiffTransform>,
3218        end_offset: ExcerptOffset,
3219        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3220    ) {
3221        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3222            (end_offset.min(insertion_end_offset), Some(hunk_info))
3223        });
3224        let unchanged_region = [(end_offset, None)];
3225
3226        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3227        {
3228            let start_offset = new_transforms.summary().excerpt_len();
3229            if end_offset <= start_offset {
3230                continue;
3231            }
3232            let summary_to_add = old_snapshot
3233                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3234
3235            if !Self::extend_last_buffer_content_transform(
3236                new_transforms,
3237                inserted_hunk_info,
3238                summary_to_add,
3239            ) {
3240                new_transforms.push(
3241                    DiffTransform::BufferContent {
3242                        summary: summary_to_add,
3243                        inserted_hunk_info,
3244                    },
3245                    (),
3246                )
3247            }
3248        }
3249    }
3250
3251    fn extend_last_buffer_content_transform(
3252        new_transforms: &mut SumTree<DiffTransform>,
3253        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3254        summary_to_add: MBTextSummary,
3255    ) -> bool {
3256        let mut did_extend = false;
3257        new_transforms.update_last(
3258            |last_transform| {
3259                if let DiffTransform::BufferContent {
3260                    summary,
3261                    inserted_hunk_info: inserted_hunk_anchor,
3262                } = last_transform
3263                    && *inserted_hunk_anchor == new_inserted_hunk_info
3264                {
3265                    *summary += summary_to_add;
3266                    did_extend = true;
3267                }
3268            },
3269            (),
3270        );
3271        did_extend
3272    }
3273
3274    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3275        let snapshot = self.snapshot(cx);
3276        let excerpt_id = range.end.excerpt_id;
3277        let point_range = range.to_point(&snapshot);
3278        let expand = !self.single_hunk_is_expanded(range, cx);
3279        let edits =
3280            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3281        if !edits.is_empty() {
3282            self.subscriptions.publish(edits);
3283        }
3284        cx.emit(Event::DiffHunksToggled);
3285        cx.emit(Event::Edited {
3286            edited_buffer: None,
3287        });
3288    }
3289}
3290
3291fn build_excerpt_ranges(
3292    ranges: impl IntoIterator<Item = Range<Point>>,
3293    context_line_count: u32,
3294    buffer_snapshot: &BufferSnapshot,
3295) -> Vec<ExcerptRange<Point>> {
3296    ranges
3297        .into_iter()
3298        .map(|range| {
3299            let start_row = range.start.row.saturating_sub(context_line_count);
3300            let start = Point::new(start_row, 0);
3301            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3302            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3303            ExcerptRange {
3304                context: start..end,
3305                primary: range,
3306            }
3307        })
3308        .collect()
3309}
3310
3311#[cfg(any(test, feature = "test-support"))]
3312impl MultiBuffer {
3313    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3314        let buffer = cx.new(|cx| Buffer::local(text, cx));
3315        cx.new(|cx| Self::singleton(buffer, cx))
3316    }
3317
3318    pub fn build_multi<const COUNT: usize>(
3319        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3320        cx: &mut gpui::App,
3321    ) -> Entity<Self> {
3322        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3323        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3324            let buffer = cx.new(|cx| Buffer::local(text, cx));
3325            let snapshot = buffer.read(cx).snapshot();
3326            let excerpt_ranges = ranges
3327                .into_iter()
3328                .map(ExcerptRange::new)
3329                .collect::<Vec<_>>();
3330            multi.update(cx, |multi, cx| {
3331                multi.set_excerpt_ranges_for_path(
3332                    PathKey::sorted(ix as u64),
3333                    buffer,
3334                    &snapshot,
3335                    excerpt_ranges,
3336                    cx,
3337                )
3338            });
3339        }
3340
3341        multi
3342    }
3343
3344    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3345        cx.new(|cx| Self::singleton(buffer, cx))
3346    }
3347
3348    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3349        cx.new(|cx| {
3350            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3351            let mutation_count = rng.random_range(1..=5);
3352            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3353            multibuffer
3354        })
3355    }
3356
3357    pub fn randomly_edit(
3358        &mut self,
3359        rng: &mut impl rand::Rng,
3360        edit_count: usize,
3361        cx: &mut Context<Self>,
3362    ) {
3363        use util::RandomCharIter;
3364
3365        let snapshot = self.read(cx);
3366        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3367        let mut last_end = None;
3368        for _ in 0..edit_count {
3369            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3370                break;
3371            }
3372
3373            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3374            let end =
3375                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3376            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3377            last_end = Some(end);
3378
3379            let mut range = start..end;
3380            if rng.random_bool(0.2) {
3381                mem::swap(&mut range.start, &mut range.end);
3382            }
3383
3384            let new_text_len = rng.random_range(0..10);
3385            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3386
3387            edits.push((range, new_text.into()));
3388        }
3389        log::info!("mutating multi-buffer with {:?}", edits);
3390        drop(snapshot);
3391
3392        self.edit(edits, None, cx);
3393    }
3394
3395    pub fn randomly_edit_excerpts(
3396        &mut self,
3397        rng: &mut impl rand::Rng,
3398        mutation_count: usize,
3399        cx: &mut Context<Self>,
3400    ) {
3401        use rand::prelude::*;
3402        use std::env;
3403        use util::RandomCharIter;
3404
3405        let max_excerpts = env::var("MAX_EXCERPTS")
3406            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3407            .unwrap_or(5);
3408
3409        let mut buffers = Vec::new();
3410        for _ in 0..mutation_count {
3411            if rng.random_bool(0.05) {
3412                log::info!("Clearing multi-buffer");
3413                self.clear(cx);
3414                continue;
3415            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3416                let ids = self.excerpt_ids();
3417                let mut excerpts = HashSet::default();
3418                for _ in 0..rng.random_range(0..ids.len()) {
3419                    excerpts.extend(ids.choose(rng).copied());
3420                }
3421
3422                let line_count = rng.random_range(0..5);
3423
3424                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3425
3426                self.expand_excerpts(
3427                    excerpts.iter().cloned(),
3428                    line_count,
3429                    ExpandExcerptDirection::UpAndDown,
3430                    cx,
3431                );
3432                continue;
3433            }
3434
3435            let excerpt_ids = self.excerpt_ids();
3436            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3437                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3438                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3439                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3440                    let buffer = buffers.last().unwrap().read(cx);
3441                    log::info!(
3442                        "Creating new buffer {} with text: {:?}",
3443                        buffer.remote_id(),
3444                        buffer.text()
3445                    );
3446                    buffers.last().unwrap().clone()
3447                } else {
3448                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3449                };
3450
3451                let buffer = buffer_handle.read(cx);
3452                let buffer_text = buffer.text();
3453                let ranges = (0..rng.random_range(0..5))
3454                    .map(|_| {
3455                        let end_ix =
3456                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3457                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3458                        ExcerptRange::new(start_ix..end_ix)
3459                    })
3460                    .collect::<Vec<_>>();
3461                log::info!(
3462                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3463                    buffer_handle.read(cx).remote_id(),
3464                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3465                    ranges
3466                        .iter()
3467                        .map(|r| &buffer_text[r.context.clone()])
3468                        .collect::<Vec<_>>()
3469                );
3470
3471                let excerpt_id =
3472                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3473                log::info!("Inserted with ids: {:?}", excerpt_id);
3474            } else {
3475                let remove_count = rng.random_range(1..=excerpt_ids.len());
3476                let mut excerpts_to_remove = excerpt_ids
3477                    .choose_multiple(rng, remove_count)
3478                    .cloned()
3479                    .collect::<Vec<_>>();
3480                let snapshot = self.snapshot.borrow();
3481                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3482                drop(snapshot);
3483                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3484                self.remove_excerpts(excerpts_to_remove, cx);
3485            }
3486        }
3487    }
3488
3489    pub fn randomly_mutate(
3490        &mut self,
3491        rng: &mut impl rand::Rng,
3492        mutation_count: usize,
3493        cx: &mut Context<Self>,
3494    ) {
3495        use rand::prelude::*;
3496
3497        if rng.random_bool(0.7) || self.singleton {
3498            let buffer = self
3499                .buffers
3500                .values()
3501                .choose(rng)
3502                .map(|state| state.buffer.clone());
3503
3504            if let Some(buffer) = buffer {
3505                buffer.update(cx, |buffer, cx| {
3506                    if rng.random() {
3507                        buffer.randomly_edit(rng, mutation_count, cx);
3508                    } else {
3509                        buffer.randomly_undo_redo(rng, cx);
3510                    }
3511                });
3512            } else {
3513                self.randomly_edit(rng, mutation_count, cx);
3514            }
3515        } else {
3516            self.randomly_edit_excerpts(rng, mutation_count, cx);
3517        }
3518
3519        self.check_invariants(cx);
3520    }
3521
3522    fn check_invariants(&self, cx: &App) {
3523        self.read(cx).check_invariants();
3524    }
3525}
3526
3527impl EventEmitter<Event> for MultiBuffer {}
3528
3529impl MultiBufferSnapshot {
3530    pub fn text(&self) -> String {
3531        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3532            .map(|chunk| chunk.text)
3533            .collect()
3534    }
3535
3536    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3537        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3538            .flat_map(|c| c.chars().rev())
3539    }
3540
3541    fn reversed_chunks_in_range(
3542        &self,
3543        range: Range<MultiBufferOffset>,
3544    ) -> ReversedMultiBufferChunks<'_> {
3545        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3546        cursor.seek(&range.end);
3547        let current_chunks = cursor.region().as_ref().map(|region| {
3548            let start_overshoot = range.start.saturating_sub(region.range.start);
3549            let end_overshoot = range.end - region.range.start;
3550            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3551            let start = region.buffer_range.start + start_overshoot;
3552            region.buffer.reversed_chunks_in_range(start..end)
3553        });
3554        ReversedMultiBufferChunks {
3555            cursor,
3556            current_chunks,
3557            start: range.start,
3558            offset: range.end,
3559        }
3560    }
3561
3562    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3563        let offset = position.to_offset(self);
3564        self.text_for_range(offset..self.len())
3565            .flat_map(|chunk| chunk.chars())
3566    }
3567
3568    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3569        self.chunks(range, false).map(|chunk| chunk.text)
3570    }
3571
3572    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3573        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3574            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3575    }
3576
3577    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3578    where
3579        T: ToOffset,
3580    {
3581        let position = position.to_offset(self);
3582        position == self.clip_offset(position, Bias::Left)
3583            && self
3584                .bytes_in_range(position..self.len())
3585                .flatten()
3586                .copied()
3587                .take(needle.len())
3588                .eq(needle.bytes())
3589    }
3590
3591    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3592        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3593    }
3594
3595    pub fn diff_hunks_in_range<T: ToPoint>(
3596        &self,
3597        range: Range<T>,
3598    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3599        let query_range = range.start.to_point(self)..range.end.to_point(self);
3600        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3601            let diff = self.diffs.get(&buffer.remote_id())?;
3602            let iter = if let Some(main_buffer) = &diff.main_buffer {
3603                let buffer_start = buffer.point_to_offset(buffer_range.start);
3604                let buffer_end = buffer.point_to_offset(buffer_range.end);
3605                itertools::Either::Left(
3606                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3607                        .map(move |hunk| (hunk, buffer, true)),
3608                )
3609            } else {
3610                let buffer_start = buffer.anchor_before(buffer_range.start);
3611                let buffer_end = buffer.anchor_after(buffer_range.end);
3612                itertools::Either::Right(
3613                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3614                        .map(move |hunk| (hunk, buffer, false)),
3615                )
3616            };
3617            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3618                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3619                    return None;
3620                }
3621                let range = if is_inverted {
3622                    hunk.diff_base_byte_range.to_point(&buffer)
3623                } else {
3624                    hunk.range.clone()
3625                };
3626                Some((range, (hunk, is_inverted)))
3627            }))
3628        })
3629        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3630            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3631            {
3632                return None;
3633            }
3634            let end_row = if range.end.column == 0 {
3635                range.end.row
3636            } else {
3637                range.end.row + 1
3638            };
3639
3640            let word_diffs =
3641                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3642                    .then(|| {
3643                        let mut word_diffs = Vec::new();
3644
3645                        if self.show_deleted_hunks || is_inverted {
3646                            let hunk_start_offset = if is_inverted {
3647                                Anchor::text(
3648                                    excerpt.id,
3649                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3650                                )
3651                                .to_offset(self)
3652                            } else {
3653                                Anchor::text(excerpt.id, hunk.buffer_range.start).to_offset(self)
3654                            };
3655
3656                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3657                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3658                            }));
3659                        }
3660
3661                        if !is_inverted {
3662                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3663                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3664                            }));
3665                        }
3666                        word_diffs
3667                    })
3668                    .unwrap_or_default();
3669
3670            let buffer_range = if is_inverted {
3671                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3672                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3673            } else {
3674                hunk.buffer_range.clone()
3675            };
3676            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3677                DiffHunkStatusKind::Deleted
3678            } else if hunk.diff_base_byte_range.is_empty() {
3679                DiffHunkStatusKind::Added
3680            } else {
3681                DiffHunkStatusKind::Modified
3682            };
3683            Some(MultiBufferDiffHunk {
3684                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3685                buffer_id: excerpt.buffer_id,
3686                excerpt_id: excerpt.id,
3687                buffer_range,
3688                word_diffs,
3689                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3690                    ..BufferOffset(hunk.diff_base_byte_range.end),
3691                status: DiffHunkStatus {
3692                    kind: status_kind,
3693                    secondary: hunk.secondary_status,
3694                },
3695            })
3696        })
3697    }
3698
3699    fn excerpts_for_range<T: ToOffset>(
3700        &self,
3701        range: Range<T>,
3702    ) -> impl Iterator<Item = &Excerpt> + '_ {
3703        let range = range.start.to_offset(self)..range.end.to_offset(self);
3704        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3705        cursor.seek(&range.start);
3706        std::iter::from_fn(move || {
3707            let region = cursor.region()?;
3708            if region.range.start > range.end
3709                || region.range.start == range.end && region.range.start > range.start
3710            {
3711                return None;
3712            }
3713            let excerpt = region.excerpt;
3714            cursor.next_excerpt_forwards();
3715            Some(excerpt)
3716        })
3717    }
3718
3719    pub fn excerpt_ids_for_range<T: ToOffset>(
3720        &self,
3721        range: Range<T>,
3722    ) -> impl Iterator<Item = ExcerptId> + '_ {
3723        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3724    }
3725
3726    pub fn buffer_ids_for_range<T: ToOffset>(
3727        &self,
3728        range: Range<T>,
3729    ) -> impl Iterator<Item = BufferId> + '_ {
3730        self.excerpts_for_range(range)
3731            .map(|excerpt| excerpt.buffer_id)
3732    }
3733
3734    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3735    ///
3736    /// The passed in anchors must be ordered.
3737    pub fn text_anchors_to_visible_anchors(
3738        &self,
3739        anchors: impl IntoIterator<Item = text::Anchor>,
3740    ) -> Vec<Option<Anchor>> {
3741        let anchors = anchors.into_iter();
3742        let mut result = Vec::with_capacity(anchors.size_hint().0);
3743        let mut anchors = anchors.peekable();
3744        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
3745        'anchors: while let Some(anchor) = anchors.peek() {
3746            let Some(buffer_id) = anchor.buffer_id else {
3747                anchors.next();
3748                result.push(None);
3749                continue 'anchors;
3750            };
3751            let mut same_buffer_anchors =
3752                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3753
3754            if let Some(locators) = self.buffer_paths.get(&buffer_id) {
3755                let Some(mut next) = same_buffer_anchors.next() else {
3756                    continue 'anchors;
3757                };
3758                'excerpts: for locator in locators.iter() {
3759                    if cursor.seek_forward(&Some(locator), Bias::Left)
3760                        && let Some(excerpt) = cursor.item()
3761                    {
3762                        loop {
3763                            // anchor is before the first excerpt
3764                            if excerpt
3765                                .range
3766                                .context
3767                                .start
3768                                .cmp(&next, &excerpt.buffer)
3769                                .is_gt()
3770                            {
3771                                // so we skip it and try the next anchor
3772                                result.push(None);
3773                                match same_buffer_anchors.next() {
3774                                    Some(anchor) => next = anchor,
3775                                    None => continue 'anchors,
3776                                }
3777                            // anchor is within the excerpt
3778                            } else if excerpt
3779                                .range
3780                                .context
3781                                .end
3782                                .cmp(&next, &excerpt.buffer)
3783                                .is_ge()
3784                            {
3785                                // record it and all following anchors that are within
3786                                result.push(Some(Anchor::text(excerpt.id, next)));
3787                                result.extend(
3788                                    same_buffer_anchors
3789                                        .peeking_take_while(|a| {
3790                                            excerpt
3791                                                .range
3792                                                .context
3793                                                .end
3794                                                .cmp(a, &excerpt.buffer)
3795                                                .is_ge()
3796                                        })
3797                                        .map(|a| Some(Anchor::text(excerpt.id, a))),
3798                                );
3799                                match same_buffer_anchors.next() {
3800                                    Some(anchor) => next = anchor,
3801                                    None => continue 'anchors,
3802                                }
3803                            // anchor is after the excerpt, try the next one
3804                            } else {
3805                                continue 'excerpts;
3806                            }
3807                        }
3808                    }
3809                }
3810                // account for `next`
3811                result.push(None);
3812            }
3813            result.extend(same_buffer_anchors.map(|_| None));
3814        }
3815
3816        result
3817    }
3818
3819    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3820        &self,
3821        ranges: impl Iterator<Item = Range<T>>,
3822    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3823        ranges.flat_map(|range| {
3824            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3825                .into_iter()
3826        })
3827    }
3828
3829    pub fn range_to_buffer_ranges<R, T>(
3830        &self,
3831        range: R,
3832    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
3833    where
3834        R: RangeBounds<T>,
3835        T: ToOffset,
3836    {
3837        self.range_to_buffer_ranges_with_context(range)
3838            .into_iter()
3839            .map(|(buffer, range, id, _context)| (buffer, range, id))
3840            .collect()
3841    }
3842
3843    pub fn range_to_buffer_ranges_with_context<R, T>(
3844        &self,
3845        range: R,
3846    ) -> Vec<(
3847        &BufferSnapshot,
3848        Range<BufferOffset>,
3849        ExcerptId,
3850        Range<text::Anchor>,
3851    )>
3852    where
3853        R: RangeBounds<T>,
3854        T: ToOffset,
3855    {
3856        let start = match range.start_bound() {
3857            Bound::Included(start) => start.to_offset(self),
3858            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3859            Bound::Unbounded => MultiBufferOffset::ZERO,
3860        };
3861        let end_bound = match range.end_bound() {
3862            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3863            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3864            Bound::Unbounded => Bound::Unbounded,
3865        };
3866        let bounds = (Bound::Included(start), end_bound);
3867
3868        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3869        cursor.seek(&start);
3870
3871        let mut result: Vec<(
3872            &BufferSnapshot,
3873            Range<BufferOffset>,
3874            ExcerptId,
3875            Range<text::Anchor>,
3876        )> = Vec::new();
3877        while let Some(region) = cursor.region() {
3878            let dominated_by_end_bound = match end_bound {
3879                Bound::Included(end) => region.range.start > end,
3880                Bound::Excluded(end) => region.range.start >= end,
3881                Bound::Unbounded => false,
3882            };
3883            if dominated_by_end_bound {
3884                break;
3885            }
3886            if region.is_main_buffer {
3887                let start_overshoot = start.saturating_sub(region.range.start);
3888                let end_offset = match end_bound {
3889                    Bound::Included(end) | Bound::Excluded(end) => end,
3890                    Bound::Unbounded => region.range.end,
3891                };
3892                let end_overshoot = end_offset.saturating_sub(region.range.start);
3893                let start = region
3894                    .buffer_range
3895                    .end
3896                    .min(region.buffer_range.start + start_overshoot);
3897                let end = region
3898                    .buffer_range
3899                    .end
3900                    .min(region.buffer_range.start + end_overshoot);
3901                let context = region.excerpt.range.context.clone();
3902                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
3903                    *excerpt_id == region.excerpt.id && prev_range.end == start
3904                }) {
3905                    prev.1.end = end;
3906                } else {
3907                    result.push((region.buffer, start..end, region.excerpt.id, context));
3908                }
3909            }
3910            cursor.next();
3911        }
3912
3913        if let Some(excerpt) = cursor.excerpt() {
3914            let dominated_by_prev_excerpt =
3915                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
3916            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3917                let excerpt_position = self.len();
3918                if bounds.contains(&excerpt_position) {
3919                    let buffer_offset =
3920                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
3921                    let context = excerpt.range.context.clone();
3922                    result.push((
3923                        &excerpt.buffer,
3924                        buffer_offset..buffer_offset,
3925                        excerpt.id,
3926                        context,
3927                    ));
3928                }
3929            }
3930        }
3931
3932        result
3933    }
3934
3935    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3936        &self,
3937        range: Range<T>,
3938    ) -> impl Iterator<
3939        Item = (
3940            &BufferSnapshot,
3941            Range<BufferOffset>,
3942            ExcerptId,
3943            Option<Anchor>,
3944        ),
3945    > + '_ {
3946        let start = range.start.to_offset(self);
3947        let end = range.end.to_offset(self);
3948
3949        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3950        cursor.seek(&start);
3951
3952        std::iter::from_fn(move || {
3953            let region = cursor.region()?;
3954            if region.range.start > end {
3955                return None;
3956            }
3957            let start_overshoot = start.saturating_sub(region.range.start);
3958            let end_overshoot = end.saturating_sub(region.range.start);
3959            let start = region
3960                .buffer_range
3961                .end
3962                .min(region.buffer_range.start + start_overshoot);
3963            let end = region
3964                .buffer_range
3965                .end
3966                .min(region.buffer_range.start + end_overshoot);
3967
3968            let region_excerpt_id = region.excerpt.id;
3969            let deleted_hunk_anchor = if region.is_main_buffer {
3970                None
3971            } else {
3972                Some(self.anchor_before(region.range.start))
3973            };
3974            let result = (
3975                region.buffer,
3976                start..end,
3977                region_excerpt_id,
3978                deleted_hunk_anchor,
3979            );
3980            cursor.next();
3981            Some(result)
3982        })
3983    }
3984
3985    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3986    /// coordinates.
3987    ///
3988    /// The given callback will be called for every excerpt intersecting the given range. It will
3989    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3990    /// The callback should return an iterator of metadata items from that buffer, each paired
3991    /// with a buffer range.
3992    ///
3993    /// The returned iterator yields each of these metadata items, paired with its range in
3994    /// multi-buffer coordinates.
3995    fn lift_buffer_metadata<'a, MBD, M, I>(
3996        &'a self,
3997        query_range: Range<MBD>,
3998        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3999    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4000    where
4001        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4002        MBD: MultiBufferDimension
4003            + Ord
4004            + Sub<Output = MBD::TextDimension>
4005            + ops::Add<MBD::TextDimension, Output = MBD>
4006            + ops::AddAssign<MBD::TextDimension>,
4007        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4008            + ops::Add<Output = MBD::TextDimension>
4009            + AddAssign<MBD::TextDimension>
4010            + Ord,
4011    {
4012        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4013        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4014
4015        // Find the excerpt and buffer offset where the given range ends.
4016        cursor.seek(&query_range.end);
4017        let mut range_end = None;
4018        while let Some(region) = cursor.region() {
4019            if region.is_main_buffer {
4020                let mut buffer_end = region.buffer_range.start;
4021                let overshoot = if query_range.end > region.range.start {
4022                    query_range.end - region.range.start
4023                } else {
4024                    <MBD::TextDimension>::default()
4025                };
4026                buffer_end = buffer_end + overshoot;
4027                range_end = Some((region.excerpt.id, buffer_end));
4028                break;
4029            }
4030            cursor.next();
4031        }
4032
4033        cursor.seek(&query_range.start);
4034
4035        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4036            && region.range.start > MBD::default()
4037        {
4038            cursor.prev()
4039        } else if let Some(region) = cursor.region()
4040            && region.is_main_buffer
4041            && region.diff_hunk_status.is_some()
4042        {
4043            cursor.prev();
4044            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4045                cursor.next();
4046            }
4047        }
4048
4049        iter::from_fn(move || {
4050            loop {
4051                let excerpt = cursor.excerpt()?;
4052
4053                // If we have already retrieved metadata for this excerpt, continue to use it.
4054                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4055                    .as_mut()
4056                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4057                {
4058                    Some(metadata)
4059                }
4060                // Otherwise, compute the intersection of the input range with the excerpt's range,
4061                // and retrieve the metadata for the resulting range.
4062                else {
4063                    let region = cursor.region()?;
4064                    let mut buffer_start;
4065                    if region.is_main_buffer {
4066                        buffer_start = region.buffer_range.start;
4067                        if query_range.start > region.range.start {
4068                            let overshoot = query_range.start - region.range.start;
4069                            buffer_start = buffer_start + overshoot;
4070                        }
4071                        buffer_start = buffer_start.min(region.buffer_range.end);
4072                    } else {
4073                        buffer_start = cursor.main_buffer_position()?;
4074                    };
4075                    let mut buffer_end = excerpt
4076                        .range
4077                        .context
4078                        .end
4079                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4080                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4081                        && excerpt.id == end_excerpt_id
4082                    {
4083                        buffer_end = buffer_end.min(end_buffer_offset);
4084                    }
4085
4086                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4087                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4088                    })
4089                };
4090
4091                // Visit each metadata item.
4092                if let Some((metadata_buffer_range, metadata)) =
4093                    metadata_iter.and_then(Iterator::next)
4094                {
4095                    // Find the multibuffer regions that contain the start and end of
4096                    // the metadata item's range.
4097                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4098                        while let Some(region) = cursor.region() {
4099                            if (region.is_main_buffer
4100                                && (region.buffer_range.end >= metadata_buffer_range.start
4101                                    || cursor.is_at_end_of_excerpt()))
4102                                || (!region.is_main_buffer
4103                                    && region.buffer_range.start == metadata_buffer_range.start)
4104                            {
4105                                break;
4106                            }
4107                            cursor.next();
4108                        }
4109                    }
4110                    let start_region = cursor.region()?.clone();
4111                    while let Some(region) = cursor.region() {
4112                        if region.is_main_buffer
4113                            && (region.buffer_range.end > metadata_buffer_range.end
4114                                || cursor.is_at_end_of_excerpt())
4115                        {
4116                            break;
4117                        }
4118                        cursor.next();
4119                    }
4120                    let end_region = cursor.region();
4121
4122                    // Convert the metadata item's range into multibuffer coordinates.
4123                    let mut start_position = start_region.range.start;
4124                    let region_buffer_start = start_region.buffer_range.start;
4125                    if start_region.is_main_buffer
4126                        && metadata_buffer_range.start > region_buffer_start
4127                    {
4128                        start_position =
4129                            start_position + (metadata_buffer_range.start - region_buffer_start);
4130                        start_position = start_position.min(start_region.range.end);
4131                    }
4132
4133                    let mut end_position = self.max_position();
4134                    if let Some(end_region) = &end_region {
4135                        end_position = end_region.range.start;
4136                        debug_assert!(end_region.is_main_buffer);
4137                        let region_buffer_start = end_region.buffer_range.start;
4138                        if metadata_buffer_range.end > region_buffer_start {
4139                            end_position =
4140                                end_position + (metadata_buffer_range.end - region_buffer_start);
4141                        }
4142                        end_position = end_position.min(end_region.range.end);
4143                    }
4144
4145                    if start_position <= query_range.end && end_position >= query_range.start {
4146                        return Some((start_position..end_position, metadata, excerpt));
4147                    }
4148                }
4149                // When there are no more metadata items for this excerpt, move to the next excerpt.
4150                else {
4151                    current_excerpt_metadata.take();
4152                    if let Some((end_excerpt_id, _)) = range_end
4153                        && excerpt.id == end_excerpt_id
4154                    {
4155                        return None;
4156                    }
4157                    cursor.next_excerpt_forwards();
4158                }
4159            }
4160        })
4161    }
4162
4163    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4164        let offset = position.to_offset(self);
4165
4166        let mut cursor = self
4167            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4168            );
4169        cursor.seek(&DimensionPair {
4170            key: offset,
4171            value: None,
4172        });
4173        cursor.seek_to_start_of_current_excerpt();
4174        let excerpt = cursor.excerpt()?;
4175
4176        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4177        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4178        let current_position = self
4179            .anchor_before(offset)
4180            .text_anchor
4181            .to_offset(&excerpt.buffer);
4182
4183        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4184            if let Some(main_buffer) = &diff.main_buffer {
4185                for hunk in diff
4186                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4187                {
4188                    if hunk.diff_base_byte_range.end >= current_position {
4189                        continue;
4190                    }
4191                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4192                    let start = Anchor::text(excerpt.id, hunk_start).to_point(self);
4193                    return Some(MultiBufferRow(start.row));
4194                }
4195            } else {
4196                let excerpt_end = excerpt
4197                    .buffer
4198                    .anchor_before(excerpt_end.min(current_position));
4199                for hunk in diff.hunks_intersecting_range_rev(
4200                    excerpt.range.context.start..excerpt_end,
4201                    &excerpt.buffer,
4202                ) {
4203                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4204                    if hunk_end >= current_position {
4205                        continue;
4206                    }
4207                    let start = Anchor::text(excerpt.id, hunk.buffer_range.start).to_point(self);
4208                    return Some(MultiBufferRow(start.row));
4209                }
4210            }
4211        }
4212
4213        loop {
4214            cursor.prev_excerpt();
4215            let excerpt = cursor.excerpt()?;
4216
4217            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4218                continue;
4219            };
4220            if let Some(main_buffer) = &diff.main_buffer {
4221                let Some(hunk) = diff
4222                    .hunks_intersecting_base_text_range_rev(
4223                        excerpt.range.context.to_offset(&excerpt.buffer),
4224                        main_buffer,
4225                    )
4226                    .next()
4227                else {
4228                    continue;
4229                };
4230                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4231                let start = Anchor::text(excerpt.id, hunk_start).to_point(self);
4232                return Some(MultiBufferRow(start.row));
4233            } else {
4234                let Some(hunk) = diff
4235                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4236                    .next()
4237                else {
4238                    continue;
4239                };
4240                let start = Anchor::text(excerpt.id, hunk.buffer_range.start).to_point(self);
4241                return Some(MultiBufferRow(start.row));
4242            }
4243        }
4244    }
4245
4246    pub fn has_diff_hunks(&self) -> bool {
4247        self.diffs.values().any(|diff| !diff.is_empty())
4248    }
4249
4250    pub fn is_inside_word<T: ToOffset>(
4251        &self,
4252        position: T,
4253        scope_context: Option<CharScopeContext>,
4254    ) -> bool {
4255        let position = position.to_offset(self);
4256        let classifier = self
4257            .char_classifier_at(position)
4258            .scope_context(scope_context);
4259        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4260        let prev_char_kind = self
4261            .reversed_chars_at(position)
4262            .next()
4263            .map(|c| classifier.kind(c));
4264        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4265    }
4266
4267    pub fn surrounding_word<T: ToOffset>(
4268        &self,
4269        start: T,
4270        scope_context: Option<CharScopeContext>,
4271    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4272        let mut start = start.to_offset(self);
4273        let mut end = start;
4274        let mut next_chars = self.chars_at(start).peekable();
4275        let mut prev_chars = self.reversed_chars_at(start).peekable();
4276
4277        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4278
4279        let word_kind = cmp::max(
4280            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4281            next_chars.peek().copied().map(|c| classifier.kind(c)),
4282        );
4283
4284        for ch in prev_chars {
4285            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4286                start -= ch.len_utf8();
4287            } else {
4288                break;
4289            }
4290        }
4291
4292        for ch in next_chars {
4293            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4294                end += ch.len_utf8();
4295            } else {
4296                break;
4297            }
4298        }
4299
4300        (start..end, word_kind)
4301    }
4302
4303    pub fn char_kind_before<T: ToOffset>(
4304        &self,
4305        start: T,
4306        scope_context: Option<CharScopeContext>,
4307    ) -> Option<CharKind> {
4308        let start = start.to_offset(self);
4309        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4310        self.reversed_chars_at(start)
4311            .next()
4312            .map(|ch| classifier.kind(ch))
4313    }
4314
4315    pub fn is_singleton(&self) -> bool {
4316        self.singleton
4317    }
4318
4319    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4320        if self.singleton {
4321            self.excerpts
4322                .iter()
4323                .next()
4324                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4325        } else {
4326            None
4327        }
4328    }
4329
4330    pub fn len(&self) -> MultiBufferOffset {
4331        self.diff_transforms.summary().output.len
4332    }
4333
4334    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4335        MBD::from_summary(&self.text_summary())
4336    }
4337
4338    pub fn is_empty(&self) -> bool {
4339        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4340    }
4341
4342    pub fn widest_line_number(&self) -> u32 {
4343        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4344        self.excerpts.summary().widest_line_number + 1
4345    }
4346
4347    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4348        let range = range.start.to_offset(self)..range.end.to_offset(self);
4349        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4350        excerpts.seek(&range.start);
4351
4352        let mut chunk;
4353        let mut has_trailing_newline;
4354        let excerpt_bytes;
4355        if let Some(region) = excerpts.region() {
4356            let mut bytes = region.buffer.bytes_in_range(
4357                region.buffer_range.start + (range.start - region.range.start)
4358                    ..(region.buffer_range.start + (range.end - region.range.start))
4359                        .min(region.buffer_range.end),
4360            );
4361            chunk = bytes.next().unwrap_or(&[][..]);
4362            excerpt_bytes = Some(bytes);
4363            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4364            if chunk.is_empty() && has_trailing_newline {
4365                chunk = b"\n";
4366                has_trailing_newline = false;
4367            }
4368        } else {
4369            chunk = &[][..];
4370            excerpt_bytes = None;
4371            has_trailing_newline = false;
4372        };
4373
4374        MultiBufferBytes {
4375            range,
4376            cursor: excerpts,
4377            excerpt_bytes,
4378            has_trailing_newline,
4379            chunk,
4380        }
4381    }
4382
4383    pub fn reversed_bytes_in_range<T: ToOffset>(
4384        &self,
4385        range: Range<T>,
4386    ) -> ReversedMultiBufferBytes<'_> {
4387        let range = range.start.to_offset(self)..range.end.to_offset(self);
4388        let mut chunks = self.reversed_chunks_in_range(range.clone());
4389        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4390        ReversedMultiBufferBytes {
4391            range,
4392            chunks,
4393            chunk,
4394        }
4395    }
4396
4397    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4398        let mut cursor = self.cursor::<Point, Point>();
4399        cursor.seek(&Point::new(start_row.0, 0));
4400        let mut result = MultiBufferRows {
4401            point: Point::new(0, 0),
4402            is_empty: self.excerpts.is_empty(),
4403            is_singleton: self.is_singleton(),
4404            cursor,
4405        };
4406        result.seek(start_row);
4407        result
4408    }
4409
4410    pub fn chunks<T: ToOffset>(
4411        &self,
4412        range: Range<T>,
4413        language_aware: bool,
4414    ) -> MultiBufferChunks<'_> {
4415        let mut chunks = MultiBufferChunks {
4416            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4417                ..ExcerptDimension(MultiBufferOffset::ZERO),
4418            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4419            excerpts: self.excerpts.cursor(()),
4420            diff_transforms: self.diff_transforms.cursor(()),
4421            diffs: &self.diffs,
4422            diff_base_chunks: None,
4423            excerpt_chunks: None,
4424            buffer_chunk: None,
4425            language_aware,
4426        };
4427        let range = range.start.to_offset(self)..range.end.to_offset(self);
4428        chunks.seek(range);
4429        chunks
4430    }
4431
4432    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4433        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4434    }
4435
4436    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4437        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4438    }
4439
4440    pub fn clip_offset_utf16(
4441        &self,
4442        offset: MultiBufferOffsetUtf16,
4443        bias: Bias,
4444    ) -> MultiBufferOffsetUtf16 {
4445        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4446    }
4447
4448    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4449        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4450            buffer.clip_point_utf16(Unclipped(point), bias)
4451        })
4452    }
4453
4454    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4455        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4456    }
4457
4458    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4459        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4460    }
4461
4462    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4463        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4464    }
4465
4466    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4467        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4468    }
4469
4470    #[instrument(skip_all)]
4471    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4472        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4473    }
4474
4475    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4476        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4477    }
4478
4479    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4480        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4481    }
4482
4483    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4484        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4485    }
4486
4487    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4488        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4489    }
4490
4491    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4492        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4493    }
4494
4495    fn clip_dimension<MBD, BD>(
4496        &self,
4497        position: MBD,
4498        bias: Bias,
4499        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4500    ) -> MBD
4501    where
4502        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4503        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4504    {
4505        let mut cursor = self.cursor::<MBD, BD>();
4506        cursor.seek(&position);
4507        if let Some(region) = cursor.region() {
4508            if position >= region.range.end {
4509                return region.range.end;
4510            }
4511            let overshoot = position - region.range.start;
4512            let mut buffer_position = region.buffer_range.start;
4513            buffer_position += overshoot;
4514            let clipped_buffer_position =
4515                clip_buffer_position(region.buffer, buffer_position, bias);
4516            let mut position = region.range.start;
4517            position += clipped_buffer_position - region.buffer_range.start;
4518            position
4519        } else {
4520            self.max_position()
4521        }
4522    }
4523
4524    #[instrument(skip_all)]
4525    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4526        &self,
4527        key: MBR1,
4528        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4529    ) -> MBR2
4530    where
4531        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4532        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4533        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4534        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4535    {
4536        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4537        cursor.seek(&DimensionPair { key, value: None });
4538        if let Some(region) = cursor.region() {
4539            if key >= region.range.end.key {
4540                return region.range.end.value.unwrap();
4541            }
4542            let start_key = region.range.start.key;
4543            let start_value = region.range.start.value.unwrap();
4544            let buffer_start_key = region.buffer_range.start.key;
4545            let buffer_start_value = region.buffer_range.start.value.unwrap();
4546            let mut buffer_key = buffer_start_key;
4547            buffer_key += key - start_key;
4548            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4549            let mut result = start_value;
4550            result += buffer_value - buffer_start_value;
4551            result
4552        } else {
4553            self.max_position()
4554        }
4555    }
4556
4557    pub fn point_to_buffer_offset<T: ToOffset>(
4558        &self,
4559        point: T,
4560    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4561        let offset = point.to_offset(self);
4562        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4563        cursor.seek(&offset);
4564        let region = cursor.region()?;
4565        let overshoot = offset - region.range.start;
4566        let buffer_offset = region.buffer_range.start + overshoot;
4567        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4568            && region.has_trailing_newline
4569            && !region.is_main_buffer
4570        {
4571            let main_buffer_position = cursor.main_buffer_position()?;
4572            let buffer_snapshot = &cursor.excerpt()?.buffer;
4573            return Some((buffer_snapshot, main_buffer_position));
4574        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4575            return None;
4576        }
4577        Some((region.buffer, buffer_offset))
4578    }
4579
4580    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4581        let mut cursor = self.cursor::<Point, Point>();
4582        cursor.seek(&point);
4583        let region = cursor.region()?;
4584        let overshoot = point - region.range.start;
4585        let buffer_point = region.buffer_range.start + overshoot;
4586        let excerpt = cursor.excerpt()?;
4587        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4588            && region.has_trailing_newline
4589            && !region.is_main_buffer
4590        {
4591            return Some((&excerpt.buffer, cursor.main_buffer_position()?));
4592        } else if buffer_point > region.buffer.max_point() {
4593            return None;
4594        }
4595        Some((region.buffer, buffer_point))
4596    }
4597
4598    pub fn suggested_indents(
4599        &self,
4600        rows: impl IntoIterator<Item = u32>,
4601        cx: &App,
4602    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4603        let mut result = BTreeMap::new();
4604        self.suggested_indents_callback(
4605            rows,
4606            &mut |row, indent| {
4607                result.insert(row, indent);
4608                ControlFlow::Continue(())
4609            },
4610            cx,
4611        );
4612        result
4613    }
4614
4615    // move this to be a generator once those are a thing
4616    pub fn suggested_indents_callback(
4617        &self,
4618        rows: impl IntoIterator<Item = u32>,
4619        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4620        cx: &App,
4621    ) {
4622        let mut rows_for_excerpt = Vec::new();
4623        let mut cursor = self.cursor::<Point, Point>();
4624        let mut rows = rows.into_iter().peekable();
4625        let mut prev_row = u32::MAX;
4626        let mut prev_language_indent_size = IndentSize::default();
4627
4628        while let Some(row) = rows.next() {
4629            cursor.seek(&Point::new(row, 0));
4630            let Some(region) = cursor.region() else {
4631                continue;
4632            };
4633
4634            // Retrieve the language and indent size once for each disjoint region being indented.
4635            let single_indent_size = if row.saturating_sub(1) == prev_row {
4636                prev_language_indent_size
4637            } else {
4638                region
4639                    .buffer
4640                    .language_indent_size_at(Point::new(row, 0), cx)
4641            };
4642            prev_language_indent_size = single_indent_size;
4643            prev_row = row;
4644
4645            let start_buffer_row = region.buffer_range.start.row;
4646            let start_multibuffer_row = region.range.start.row;
4647            let end_multibuffer_row = region.range.end.row;
4648
4649            rows_for_excerpt.push(row);
4650            while let Some(next_row) = rows.peek().copied() {
4651                if end_multibuffer_row > next_row {
4652                    rows_for_excerpt.push(next_row);
4653                    rows.next();
4654                } else {
4655                    break;
4656                }
4657            }
4658
4659            let buffer_rows = rows_for_excerpt
4660                .drain(..)
4661                .map(|row| start_buffer_row + row - start_multibuffer_row);
4662            let buffer_indents = region
4663                .buffer
4664                .suggested_indents(buffer_rows, single_indent_size);
4665            for (row, indent) in buffer_indents {
4666                if cb(
4667                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4668                    indent,
4669                )
4670                .is_break()
4671                {
4672                    return;
4673                }
4674            }
4675        }
4676    }
4677
4678    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4679        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4680            let mut size = buffer.indent_size_for_line(range.start.row);
4681            size.len = size
4682                .len
4683                .min(range.end.column)
4684                .saturating_sub(range.start.column);
4685            size
4686        } else {
4687            IndentSize::spaces(0)
4688        }
4689    }
4690
4691    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4692        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4693            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4694        } else {
4695            LineIndent::spaces(0)
4696        }
4697    }
4698
4699    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4700        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4701
4702        if self.language_settings(cx).extend_comment_on_newline
4703            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4704        {
4705            let delimiters = language_scope.line_comment_prefixes();
4706            for delimiter in delimiters {
4707                if *self
4708                    .chars_at(Point::new(row.0, indent.len() as u32))
4709                    .take(delimiter.chars().count())
4710                    .collect::<String>()
4711                    .as_str()
4712                    == **delimiter
4713                {
4714                    indent.push_str(delimiter);
4715                    break;
4716                }
4717            }
4718        }
4719
4720        indent
4721    }
4722
4723    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4724    where
4725        T: ToOffset,
4726    {
4727        for char in self.reversed_chars_at(position) {
4728            if !char.is_whitespace() {
4729                return false;
4730            }
4731            if char == '\n' {
4732                return true;
4733            }
4734        }
4735        true
4736    }
4737
4738    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4739        while row.0 > 0 {
4740            row.0 -= 1;
4741            if !self.is_line_blank(row) {
4742                return Some(row);
4743            }
4744        }
4745        None
4746    }
4747
4748    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4749        if let Some((_, range)) = self.buffer_line_for_row(row) {
4750            range.end.column - range.start.column
4751        } else {
4752            0
4753        }
4754    }
4755
4756    pub fn buffer_line_for_row(
4757        &self,
4758        row: MultiBufferRow,
4759    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4760        let mut cursor = self.cursor::<Point, Point>();
4761        let point = Point::new(row.0, 0);
4762        cursor.seek(&point);
4763        let region = cursor.region()?;
4764        let overshoot = point.min(region.range.end) - region.range.start;
4765        let buffer_point = region.buffer_range.start + overshoot;
4766        if buffer_point.row > region.buffer_range.end.row {
4767            return None;
4768        }
4769        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4770        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4771            .min(region.buffer_range.end);
4772        Some((region.buffer, line_start..line_end))
4773    }
4774
4775    pub fn max_point(&self) -> Point {
4776        self.text_summary().lines
4777    }
4778
4779    pub fn max_row(&self) -> MultiBufferRow {
4780        MultiBufferRow(self.text_summary().lines.row)
4781    }
4782
4783    pub fn text_summary(&self) -> MBTextSummary {
4784        self.diff_transforms.summary().output
4785    }
4786
4787    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4788    where
4789        MBD: MultiBufferDimension + AddAssign,
4790        O: ToOffset,
4791    {
4792        let range = range.start.to_offset(self)..range.end.to_offset(self);
4793        let mut cursor = self
4794            .diff_transforms
4795            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4796        cursor.seek(&range.start, Bias::Right);
4797
4798        let Some(first_transform) = cursor.item() else {
4799            return MBD::from_summary(&MBTextSummary::default());
4800        };
4801
4802        let diff_transform_start = cursor.start().0;
4803        let diff_transform_end = cursor.end().0;
4804        let diff_start = range.start;
4805        let start_overshoot = diff_start - diff_transform_start;
4806        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4807
4808        let mut result = match first_transform {
4809            DiffTransform::BufferContent { .. } => {
4810                let excerpt_start = cursor.start().1 + start_overshoot;
4811                let excerpt_end = cursor.start().1 + end_overshoot;
4812                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4813            }
4814            DiffTransform::DeletedHunk {
4815                buffer_id,
4816                base_text_byte_range,
4817                has_trailing_newline,
4818                ..
4819            } => {
4820                let buffer_start = base_text_byte_range.start + start_overshoot;
4821                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4822                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4823                    panic!("{:?} is in non-existent deleted hunk", range.start)
4824                };
4825
4826                let include_trailing_newline =
4827                    *has_trailing_newline && range.end >= diff_transform_end;
4828                if include_trailing_newline {
4829                    buffer_end -= 1;
4830                }
4831
4832                let mut summary = base_text
4833                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4834
4835                if include_trailing_newline {
4836                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4837                        &TextSummary::newline(),
4838                    ))
4839                }
4840
4841                let mut result = MBD::default();
4842                result.add_text_dim(&summary);
4843                result
4844            }
4845        };
4846        if range.end < diff_transform_end {
4847            return result;
4848        }
4849
4850        cursor.next();
4851        result.add_mb_text_summary(
4852            &cursor
4853                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4854                .0,
4855        );
4856
4857        let Some(last_transform) = cursor.item() else {
4858            return result;
4859        };
4860
4861        let overshoot = range.end - cursor.start().0;
4862        let suffix = match last_transform {
4863            DiffTransform::BufferContent { .. } => {
4864                let end = cursor.start().1 + overshoot;
4865                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4866            }
4867            DiffTransform::DeletedHunk {
4868                base_text_byte_range,
4869                buffer_id,
4870                has_trailing_newline,
4871                ..
4872            } => {
4873                let buffer_end = base_text_byte_range.start + overshoot;
4874                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4875                    panic!("{:?} is in non-existent deleted hunk", range.end)
4876                };
4877
4878                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4879                    base_text_byte_range.start..buffer_end,
4880                );
4881                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4882                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4883                        &TextSummary::from("\n"),
4884                    ))
4885                }
4886
4887                let mut result = MBD::default();
4888                result.add_text_dim(&suffix);
4889                result
4890            }
4891        };
4892
4893        result += suffix;
4894        result
4895    }
4896
4897    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4898    where
4899        MBD: MultiBufferDimension + AddAssign,
4900    {
4901        let mut summary = MBD::default();
4902        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4903        cursor.seek(&range.start, Bias::Right);
4904        if let Some(excerpt) = cursor.item() {
4905            let mut end_before_newline = cursor.end();
4906            if excerpt.has_trailing_newline {
4907                end_before_newline -= 1;
4908            }
4909
4910            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4911            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4912            let end_in_excerpt =
4913                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4914            summary.add_text_dim(
4915                &excerpt
4916                    .buffer
4917                    .text_summary_for_range::<MBD::TextDimension, _>(
4918                        start_in_excerpt..end_in_excerpt,
4919                    ),
4920            );
4921
4922            if range.end > end_before_newline {
4923                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4924            }
4925
4926            cursor.next();
4927        }
4928
4929        if range.end > *cursor.start() {
4930            summary += cursor
4931                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4932                .0;
4933            if let Some(excerpt) = cursor.item() {
4934                range.end = cmp::max(*cursor.start(), range.end);
4935
4936                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4937                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4938                summary.add_text_dim(
4939                    &excerpt
4940                        .buffer
4941                        .text_summary_for_range::<MBD::TextDimension, _>(
4942                            excerpt_start..end_in_excerpt,
4943                        ),
4944                );
4945            }
4946        }
4947
4948        summary
4949    }
4950
4951    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4952    where
4953        MBD: MultiBufferDimension
4954            + Ord
4955            + Sub<Output = MBD::TextDimension>
4956            + Sub<MBD::TextDimension, Output = MBD>
4957            + AddAssign<MBD::TextDimension>
4958            + Add<MBD::TextDimension, Output = MBD>,
4959        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4960    {
4961        let target = self.anchor_seek_target(*anchor);
4962        let Some((_, text_anchor, _)) = anchor.text_anchor() else {
4963            if anchor.is_min() {
4964                return MBD::default();
4965            } else {
4966                return MBD::from_summary(&self.text_summary());
4967            }
4968        };
4969
4970        let (start, _, item) = self
4971            .excerpts
4972            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4973        let start = MBD::from_summary(&start.text);
4974
4975        let excerpt_start_position = ExcerptDimension(start);
4976        if self.diff_transforms.is_empty() {
4977            if let Some(excerpt) = item {
4978                if !excerpt.contains(anchor) {
4979                    return excerpt_start_position.0;
4980                }
4981                let excerpt_buffer_start = excerpt
4982                    .range
4983                    .context
4984                    .start
4985                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4986                let excerpt_buffer_end = excerpt
4987                    .range
4988                    .context
4989                    .end
4990                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4991                let buffer_summary = text_anchor.summary::<MBD::TextDimension>(&excerpt.buffer);
4992                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4993                let mut position = excerpt_start_position;
4994                if summary > excerpt_buffer_start {
4995                    position += summary - excerpt_buffer_start;
4996                }
4997
4998                position.0
4999            } else {
5000                excerpt_start_position.0
5001            }
5002        } else {
5003            let mut diff_transforms_cursor = self
5004                .diff_transforms
5005                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5006            diff_transforms_cursor.next();
5007
5008            if let Some(excerpt) = item {
5009                if !excerpt.contains(anchor) {
5010                    return self.summary_for_excerpt_position_without_hunks(
5011                        Bias::Left,
5012                        excerpt_start_position,
5013                        &mut diff_transforms_cursor,
5014                    );
5015                }
5016                let excerpt_buffer_start = excerpt
5017                    .range
5018                    .context
5019                    .start
5020                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5021                let excerpt_buffer_end = excerpt
5022                    .range
5023                    .context
5024                    .end
5025                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5026                let buffer_summary = text_anchor.summary::<MBD::TextDimension>(&excerpt.buffer);
5027                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5028                let mut position = excerpt_start_position;
5029                if summary > excerpt_buffer_start {
5030                    position += summary - excerpt_buffer_start;
5031                }
5032
5033                if diff_transforms_cursor.start().0 < position {
5034                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5035                }
5036                self.summary_for_anchor_with_excerpt_position(
5037                    text_anchor,
5038                    anchor.diff_base_anchor(),
5039                    position,
5040                    &mut diff_transforms_cursor,
5041                    &excerpt.buffer,
5042                )
5043            } else {
5044                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5045                self.summary_for_excerpt_position_without_hunks(
5046                    Bias::Right,
5047                    excerpt_start_position,
5048                    &mut diff_transforms_cursor,
5049                )
5050            }
5051        }
5052    }
5053
5054    /// Maps an anchor's excerpt-space position to its output-space position by
5055    /// walking the diff transforms. The cursor is shared across consecutive
5056    /// calls, so it may already be partway through the transform list.
5057    fn summary_for_anchor_with_excerpt_position<MBD>(
5058        &self,
5059        text_anchor: text::Anchor,
5060        diff_base_anchor: Option<text::Anchor>,
5061        excerpt_position: ExcerptDimension<MBD>,
5062        diff_transforms: &mut Cursor<
5063            DiffTransform,
5064            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5065        >,
5066        excerpt_buffer: &text::BufferSnapshot,
5067    ) -> MBD
5068    where
5069        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5070    {
5071        loop {
5072            let transform_end_position = diff_transforms.end().0;
5073            let item = diff_transforms.item();
5074            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5075
5076            // A right-biased anchor at a transform boundary belongs to the
5077            // *next* transform, so advance past the current one.
5078            if text_anchor.bias == Bias::Right && at_transform_end {
5079                diff_transforms.next();
5080                continue;
5081            }
5082
5083            let mut position = diff_transforms.start().1;
5084            match item {
5085                Some(DiffTransform::DeletedHunk {
5086                    buffer_id,
5087                    base_text_byte_range,
5088                    hunk_info,
5089                    ..
5090                }) => {
5091                    if let Some(diff_base_anchor) = &diff_base_anchor
5092                        && let Some(base_text) =
5093                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5094                        && diff_base_anchor.is_valid(&base_text)
5095                    {
5096                        // The anchor carries a diff-base position — resolve it
5097                        // to a location inside the deleted hunk.
5098                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5099                        if base_text_offset >= base_text_byte_range.start
5100                            && base_text_offset <= base_text_byte_range.end
5101                        {
5102                            let position_in_hunk = base_text
5103                                .text_summary_for_range::<MBD::TextDimension, _>(
5104                                    base_text_byte_range.start..base_text_offset,
5105                                );
5106                            position.0.add_text_dim(&position_in_hunk);
5107                        } else if at_transform_end {
5108                            // diff_base offset falls outside this hunk's range;
5109                            // advance to see if the next transform is a better fit.
5110                            diff_transforms.next();
5111                            continue;
5112                        }
5113                    } else if at_transform_end
5114                        && text_anchor
5115                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5116                            .is_gt()
5117                    {
5118                        // The anchor has no (valid) diff-base position, so it
5119                        // belongs in the buffer content, not in the deleted
5120                        // hunk. However, after an edit deletes the text between
5121                        // the hunk boundary and this anchor, both resolve to
5122                        // the same excerpt_position—landing us here on the
5123                        // DeletedHunk left behind by the shared cursor. Use the
5124                        // CRDT ordering to detect that the anchor is strictly
5125                        // *past* the hunk boundary and skip to the following
5126                        // BufferContent.
5127                        diff_transforms.next();
5128                        continue;
5129                    }
5130                }
5131                _ => {
5132                    // On a BufferContent (or no transform). If the anchor
5133                    // carries a diff_base_anchor it needs a DeletedHunk, so
5134                    // advance to find one.
5135                    if at_transform_end && diff_base_anchor.is_some() {
5136                        diff_transforms.next();
5137                        continue;
5138                    }
5139                    let overshoot = excerpt_position - diff_transforms.start().0;
5140                    position += overshoot;
5141                }
5142            }
5143
5144            return position.0;
5145        }
5146    }
5147
5148    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5149    fn summary_for_excerpt_position_without_hunks<MBD>(
5150        &self,
5151        bias: Bias,
5152        excerpt_position: ExcerptDimension<MBD>,
5153        diff_transforms: &mut Cursor<
5154            DiffTransform,
5155            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5156        >,
5157    ) -> MBD
5158    where
5159        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5160    {
5161        loop {
5162            let transform_end_position = diff_transforms.end().0;
5163            let item = diff_transforms.item();
5164            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5165
5166            // A right-biased anchor at a transform boundary belongs to the
5167            // *next* transform, so advance past the current one.
5168            if bias == Bias::Right && at_transform_end {
5169                diff_transforms.next();
5170                continue;
5171            }
5172
5173            let mut position = diff_transforms.start().1;
5174            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5175                let overshoot = excerpt_position - diff_transforms.start().0;
5176                position += overshoot;
5177            }
5178
5179            return position.0;
5180        }
5181    }
5182
5183    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5184        let Some((_, text_anchor, _)) = anchor.text_anchor() else {
5185            if anchor.is_min() {
5186                return ExcerptOffset::default();
5187            } else {
5188                return self.excerpts.summary().len();
5189            }
5190        };
5191        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5192        let target = self.anchor_seek_target(*anchor);
5193
5194        cursor.seek(&target, Bias::Left);
5195        if cursor.item().is_none() && anchor.is_max() {
5196            cursor.prev();
5197        }
5198
5199        let mut position = cursor.start().len();
5200        if let Some(excerpt) = cursor.item()
5201            && (excerpt.contains(anchor) || anchor.is_max())
5202        {
5203            let excerpt_buffer_start = excerpt
5204                .buffer
5205                .offset_for_anchor(&excerpt.range.context.start);
5206            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5207            let buffer_position = cmp::min(
5208                excerpt_buffer_end,
5209                excerpt.buffer.offset_for_anchor(&text_anchor),
5210            );
5211            if buffer_position > excerpt_buffer_start {
5212                position += buffer_position - excerpt_buffer_start;
5213            }
5214        }
5215        position
5216    }
5217
5218    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5219        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5220            excerpt_id = *replacement;
5221        }
5222        excerpt_id
5223    }
5224
5225    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5226    where
5227        MBD: MultiBufferDimension
5228            + Ord
5229            + Sub<Output = MBD::TextDimension>
5230            + AddAssign<MBD::TextDimension>,
5231        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5232        I: 'a + IntoIterator<Item = &'a Anchor>,
5233    {
5234        let mut anchors = anchors.into_iter().peekable();
5235        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5236        let mut diff_transforms_cursor = self
5237            .diff_transforms
5238            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5239        diff_transforms_cursor.next();
5240
5241        let mut summaries = Vec::new();
5242        while let Some(anchor) = anchors.peek() {
5243            let anchor = **anchor;
5244            let target = self.anchor_seek_target(anchor);
5245
5246            cursor.seek_forward(&target, Bias::Left);
5247
5248            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5249                cursor
5250                    .item()
5251                    .is_some_and(|excerpt| excerpt.contains(&anchor))
5252            });
5253
5254            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5255            if let Some(excerpt) = cursor.item() {
5256                if !excerpt.contains(&anchor) {
5257                    let position = self.summary_for_excerpt_position_without_hunks(
5258                        Bias::Left,
5259                        excerpt_start_position,
5260                        &mut diff_transforms_cursor,
5261                    );
5262                    summaries.extend(excerpt_anchors.map(|_| position));
5263                    continue;
5264                }
5265                let excerpt_buffer_start = excerpt
5266                    .range
5267                    .context
5268                    .start
5269                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5270                let excerpt_buffer_end = excerpt
5271                    .range
5272                    .context
5273                    .end
5274                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5275                for (buffer_summary, (text_anchor, diff_base_anchor)) in excerpt
5276                    .buffer
5277                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5278                    excerpt_anchors.filter_map(|a| {
5279                        let (_, text_anchor, diff_base_anchor) = a.text_anchor()?;
5280                        Some((text_anchor, (text_anchor, diff_base_anchor)))
5281                    }),
5282                ) {
5283                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5284                    let mut position = excerpt_start_position;
5285                    if summary > excerpt_buffer_start {
5286                        position += summary - excerpt_buffer_start;
5287                    }
5288
5289                    if diff_transforms_cursor.start().0 < position {
5290                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5291                    }
5292
5293                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5294                        text_anchor,
5295                        diff_base_anchor,
5296                        position,
5297                        &mut diff_transforms_cursor,
5298                        &excerpt.buffer,
5299                    ));
5300                }
5301            } else {
5302                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5303                let position = self.summary_for_excerpt_position_without_hunks(
5304                    Bias::Right,
5305                    excerpt_start_position,
5306                    &mut diff_transforms_cursor,
5307                );
5308                summaries.extend(excerpt_anchors.map(|_| position));
5309            }
5310        }
5311
5312        summaries
5313    }
5314
5315    pub fn dimensions_from_points<'a, MBD>(
5316        &'a self,
5317        points: impl 'a + IntoIterator<Item = Point>,
5318    ) -> impl 'a + Iterator<Item = MBD>
5319    where
5320        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5321    {
5322        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5323        cursor.seek(&DimensionPair {
5324            key: Point::default(),
5325            value: None,
5326        });
5327        let mut points = points.into_iter();
5328        iter::from_fn(move || {
5329            let point = points.next()?;
5330
5331            cursor.seek_forward(&DimensionPair {
5332                key: point,
5333                value: None,
5334            });
5335
5336            if let Some(region) = cursor.region() {
5337                let overshoot = point - region.range.start.key;
5338                let buffer_point = region.buffer_range.start + overshoot;
5339                let mut position = region.range.start.value.unwrap();
5340                position.add_text_dim(
5341                    &region
5342                        .buffer
5343                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5344                );
5345                if point == region.range.end.key && region.has_trailing_newline {
5346                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5347                }
5348                Some(position)
5349            } else {
5350                Some(MBD::from_summary(&self.text_summary()))
5351            }
5352        })
5353    }
5354
5355    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5356    where
5357        I: 'a + IntoIterator<Item = &'a Anchor>,
5358    {
5359        let mut anchors = anchors.into_iter().enumerate().peekable();
5360        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5361        cursor.next();
5362
5363        let mut result = Vec::new();
5364
5365        while let Some((_, anchor)) = anchors.peek() {
5366            let old_excerpt_id = anchor.excerpt_id;
5367
5368            // Find the location where this anchor's excerpt should be.
5369            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5370            cursor.seek_forward(&Some(old_locator), Bias::Left);
5371
5372            let next_excerpt = cursor.item();
5373            let prev_excerpt = cursor.prev_item();
5374
5375            // Process all of the anchors for this excerpt.
5376            while let Some((anchor_ix, &anchor)) =
5377                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5378            {
5379                let mut anchor = anchor;
5380
5381                // Leave min and max anchors unchanged if invalid or
5382                // if the old excerpt still exists at this location
5383                let mut kept_position = next_excerpt
5384                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5385                    || old_excerpt_id == ExcerptId::max()
5386                    || old_excerpt_id == ExcerptId::min();
5387
5388                // If the old excerpt no longer exists at this location, then attempt to
5389                // find an equivalent position for this anchor in an adjacent excerpt.
5390                if !kept_position {
5391                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5392                        if excerpt.contains(&anchor) {
5393                            anchor.excerpt_id = excerpt.id;
5394                            kept_position = true;
5395                            break;
5396                        }
5397                    }
5398                }
5399
5400                // If there's no adjacent excerpt that contains the anchor's position,
5401                // then report that the anchor has lost its position.
5402                if !kept_position {
5403                    anchor = if let Some(excerpt) = next_excerpt {
5404                        let mut text_anchor = excerpt
5405                            .range
5406                            .context
5407                            .start
5408                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5409                        if text_anchor
5410                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5411                            .is_gt()
5412                        {
5413                            text_anchor = excerpt.range.context.end;
5414                        }
5415                        Anchor::text(excerpt.id, text_anchor)
5416                    } else if let Some(excerpt) = prev_excerpt {
5417                        let mut text_anchor = excerpt
5418                            .range
5419                            .context
5420                            .end
5421                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5422                        if text_anchor
5423                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5424                            .is_lt()
5425                        {
5426                            text_anchor = excerpt.range.context.start;
5427                        }
5428                        Anchor::text(excerpt.id, text_anchor)
5429                    } else if anchor.text_anchor.bias == Bias::Left {
5430                        Anchor::min()
5431                    } else {
5432                        Anchor::max()
5433                    };
5434                }
5435
5436                result.push((anchor_ix, anchor, kept_position));
5437            }
5438        }
5439        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5440        result
5441    }
5442
5443    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5444        self.anchor_at(position, Bias::Left)
5445    }
5446
5447    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5448        self.anchor_at(position, Bias::Right)
5449    }
5450
5451    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5452        let offset = position.to_offset(self);
5453
5454        // Find the given position in the diff transforms. Determine the corresponding
5455        // offset in the excerpts, and whether the position is within a deleted hunk.
5456        let mut diff_transforms = self
5457            .diff_transforms
5458            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5459        diff_transforms.seek(&offset, Bias::Right);
5460
5461        if offset == diff_transforms.start().0
5462            && bias == Bias::Left
5463            && let Some(prev_item) = diff_transforms.prev_item()
5464            && let DiffTransform::DeletedHunk { .. } = prev_item
5465        {
5466            diff_transforms.prev();
5467        }
5468        let offset_in_transform = offset - diff_transforms.start().0;
5469        let mut excerpt_offset = diff_transforms.start().1;
5470        let mut diff_base_anchor = None;
5471        if let Some(DiffTransform::DeletedHunk {
5472            buffer_id,
5473            base_text_byte_range,
5474            has_trailing_newline,
5475            ..
5476        }) = diff_transforms.item()
5477        {
5478            let diff = self.diffs.get(buffer_id).expect("missing diff");
5479            if offset_in_transform > base_text_byte_range.len() {
5480                debug_assert!(*has_trailing_newline);
5481                bias = Bias::Right;
5482            } else {
5483                diff_base_anchor = Some(
5484                    diff.base_text()
5485                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5486                );
5487                bias = Bias::Left;
5488            }
5489        } else {
5490            excerpt_offset += MultiBufferOffset(offset_in_transform);
5491        };
5492
5493        let mut excerpts = self
5494            .excerpts
5495            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5496        excerpts.seek(&excerpt_offset, Bias::Right);
5497        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5498            excerpts.prev();
5499        }
5500        if let Some(excerpt) = excerpts.item() {
5501            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5502            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5503                overshoot -= 1;
5504                bias = Bias::Right;
5505            }
5506
5507            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5508            let text_anchor =
5509                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5510            let anchor = Anchor::text(excerpt.id, text_anchor);
5511            match diff_base_anchor {
5512                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5513                None => anchor,
5514            }
5515        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5516        {
5517            Anchor::min()
5518        } else {
5519            Anchor::max()
5520        }
5521    }
5522
5523    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5524    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5525        let (excerpt, buffer, _) = self.as_singleton()?;
5526        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5527            Some(Anchor::text(excerpt, text_anchor))
5528        } else {
5529            None
5530        }
5531    }
5532
5533    /// Returns an anchor for the given excerpt and text anchor,
5534    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5535    pub fn anchor_range_in_excerpt(
5536        &self,
5537        excerpt_id: ExcerptId,
5538        text_anchor: Range<text::Anchor>,
5539    ) -> Option<Range<Anchor>> {
5540        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5541
5542        Some(
5543            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5544                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5545        )
5546    }
5547
5548    /// Returns an anchor for the given excerpt and text anchor,
5549    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5550    pub fn anchor_in_excerpt(
5551        &self,
5552        excerpt_id: ExcerptId,
5553        text_anchor: text::Anchor,
5554    ) -> Option<Anchor> {
5555        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5556        Self::anchor_in_excerpt_(excerpt, text_anchor)
5557    }
5558
5559    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5560    pub fn anchors_in_excerpt(
5561        &self,
5562        excerpt_id: ExcerptId,
5563        text_anchors: impl IntoIterator<Item = text::Anchor>,
5564    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5565        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5566        Some(
5567            text_anchors
5568                .into_iter()
5569                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5570        )
5571    }
5572
5573    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5574        match text_anchor.buffer_id {
5575            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5576            Some(_) => return None,
5577            None if text_anchor.is_max() || text_anchor.is_min() => {
5578                return Some(Anchor::text(excerpt.id, text_anchor));
5579            }
5580            None => return None,
5581        }
5582
5583        let context = &excerpt.range.context;
5584        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5585            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5586        {
5587            return None;
5588        }
5589
5590        Some(Anchor::text(excerpt.id, text_anchor))
5591    }
5592
5593    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5594        Some(self.excerpt(excerpt_id)?.range.context.clone())
5595    }
5596
5597    pub fn excerpt_range_for_excerpt(
5598        &self,
5599        excerpt_id: ExcerptId,
5600    ) -> Option<ExcerptRange<text::Anchor>> {
5601        Some(self.excerpt(excerpt_id)?.range.clone())
5602    }
5603
5604    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5605        if anchor.is_min() || anchor.is_max() {
5606            // todo(lw): should be `!self.is_empty()`
5607            true
5608        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5609            excerpt.buffer.can_resolve(&anchor.text_anchor)
5610        } else {
5611            false
5612        }
5613    }
5614
5615    pub fn excerpts(
5616        &self,
5617    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5618        self.excerpts
5619            .iter()
5620            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5621    }
5622
5623    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5624    where
5625        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5626        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5627    {
5628        let excerpts = self.excerpts.cursor(());
5629        let diff_transforms = self.diff_transforms.cursor(());
5630        MultiBufferCursor {
5631            excerpts,
5632            diff_transforms,
5633            diffs: &self.diffs,
5634            cached_region: OnceCell::new(),
5635        }
5636    }
5637
5638    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5639        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5640        let mut excerpts = self
5641            .excerpts
5642            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5643        excerpts.seek(&Some(start_locator), Bias::Left);
5644        excerpts.prev();
5645
5646        let mut diff_transforms = self
5647            .diff_transforms
5648            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5649        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5650        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5651            diff_transforms.next();
5652        }
5653
5654        let excerpt = excerpts.item()?;
5655        Some(MultiBufferExcerpt {
5656            excerpt,
5657            offset: diff_transforms.start().output_dimension.0,
5658            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5659            excerpt_offset: excerpts.start().1,
5660            diff_transforms,
5661        })
5662    }
5663
5664    pub fn excerpt_boundaries_in_range<R, T>(
5665        &self,
5666        range: R,
5667    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5668    where
5669        R: RangeBounds<T>,
5670        T: ToOffset,
5671    {
5672        let start_offset;
5673        let start = match range.start_bound() {
5674            Bound::Included(start) => {
5675                start_offset = start.to_offset(self);
5676                Bound::Included(start_offset)
5677            }
5678            Bound::Excluded(_) => {
5679                panic!("not supported")
5680            }
5681            Bound::Unbounded => {
5682                start_offset = MultiBufferOffset::ZERO;
5683                Bound::Unbounded
5684            }
5685        };
5686        let end = match range.end_bound() {
5687            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5688            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5689            Bound::Unbounded => Bound::Unbounded,
5690        };
5691        let bounds = (start, end);
5692        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5693        cursor.seek(&DimensionPair {
5694            key: start_offset,
5695            value: None,
5696        });
5697
5698        if cursor
5699            .fetch_excerpt_with_range()
5700            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5701        {
5702            cursor.prev_excerpt();
5703        } else {
5704            cursor.seek_to_start_of_current_excerpt();
5705        }
5706        let mut prev_region = cursor
5707            .fetch_excerpt_with_range()
5708            .map(|(excerpt, _)| excerpt);
5709
5710        cursor.next_excerpt_forwards();
5711
5712        iter::from_fn(move || {
5713            loop {
5714                if self.singleton {
5715                    return None;
5716                }
5717
5718                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5719                cursor.next_excerpt_forwards();
5720                if !bounds.contains(&next_range.start.key) {
5721                    prev_region = Some(next_excerpt);
5722                    continue;
5723                }
5724
5725                let next_region_start = next_range.start.value.unwrap();
5726                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5727                    range.start.value.unwrap()
5728                } else {
5729                    self.max_point()
5730                };
5731
5732                let prev = prev_region.as_ref().map(|region| ExcerptBoundaryInfo {
5733                    id: region.id,
5734                    buffer: region.buffer.clone(),
5735                    buffer_id: region.buffer_id,
5736                    range: region.range.clone(),
5737                    end_row: MultiBufferRow(next_region_start.row),
5738                });
5739
5740                let next = ExcerptBoundaryInfo {
5741                    id: next_excerpt.id,
5742                    buffer: next_excerpt.buffer.clone(),
5743                    buffer_id: next_excerpt.buffer_id,
5744                    range: next_excerpt.range.clone(),
5745                    end_row: if next_excerpt.has_trailing_newline {
5746                        MultiBufferRow(next_region_end.row - 1)
5747                    } else {
5748                        MultiBufferRow(next_region_end.row)
5749                    },
5750                };
5751
5752                let row = MultiBufferRow(next_region_start.row);
5753
5754                prev_region = Some(next_excerpt);
5755
5756                return Some(ExcerptBoundary { row, prev, next });
5757            }
5758        })
5759    }
5760
5761    pub fn edit_count(&self) -> usize {
5762        self.edit_count
5763    }
5764
5765    pub fn non_text_state_update_count(&self) -> usize {
5766        self.non_text_state_update_count
5767    }
5768
5769    /// Returns the smallest enclosing bracket ranges containing the given range or
5770    /// None if no brackets contain range or the range is not contained in a single
5771    /// excerpt
5772    ///
5773    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5774    #[ztracing::instrument(skip_all)]
5775    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5776        &self,
5777        range: Range<T>,
5778        range_filter: Option<
5779            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5780        >,
5781    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5782        let range = range.start.to_offset(self)..range.end.to_offset(self);
5783        let mut excerpt = self.excerpt_containing(range.clone())?;
5784        let buffer = excerpt.buffer();
5785        let excerpt_buffer_range = excerpt.buffer_range();
5786
5787        // Filter to ranges contained in the excerpt
5788        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5789            excerpt_buffer_range.contains(&BufferOffset(open.start))
5790                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5791                && range_filter.is_none_or(|filter| {
5792                    filter(
5793                        buffer,
5794                        BufferOffset(open.start)..BufferOffset(close.end),
5795                        BufferOffset(close.start)..BufferOffset(close.end),
5796                    )
5797                })
5798        };
5799
5800        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5801            excerpt.map_range_to_buffer(range),
5802            Some(&range_filter),
5803        )?;
5804
5805        Some((
5806            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5807            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5808        ))
5809    }
5810
5811    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5812    /// not contained in a single excerpt
5813    pub fn enclosing_bracket_ranges<T: ToOffset>(
5814        &self,
5815        range: Range<T>,
5816    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5817    {
5818        let range = range.start.to_offset(self)..range.end.to_offset(self);
5819        let mut excerpt = self.excerpt_containing(range.clone())?;
5820
5821        Some(
5822            excerpt
5823                .buffer()
5824                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5825                .filter_map(move |pair| {
5826                    let open_range =
5827                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5828                    let close_range =
5829                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5830                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5831                        Some((
5832                            excerpt.map_range_from_buffer(open_range),
5833                            excerpt.map_range_from_buffer(close_range),
5834                        ))
5835                    } else {
5836                        None
5837                    }
5838                }),
5839        )
5840    }
5841
5842    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5843    /// not contained in a single excerpt
5844    pub fn text_object_ranges<T: ToOffset>(
5845        &self,
5846        range: Range<T>,
5847        options: TreeSitterOptions,
5848    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5849        let range = range.start.to_offset(self)..range.end.to_offset(self);
5850        self.excerpt_containing(range.clone())
5851            .map(|mut excerpt| {
5852                excerpt
5853                    .buffer()
5854                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5855                    .filter_map(move |(range, text_object)| {
5856                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5857                        if excerpt.contains_buffer_range(range.clone()) {
5858                            Some((excerpt.map_range_from_buffer(range), text_object))
5859                        } else {
5860                            None
5861                        }
5862                    })
5863            })
5864            .into_iter()
5865            .flatten()
5866    }
5867
5868    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5869    /// not contained in a single excerpt
5870    pub fn bracket_ranges<T: ToOffset>(
5871        &self,
5872        range: Range<T>,
5873    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5874    {
5875        let range = range.start.to_offset(self)..range.end.to_offset(self);
5876        let mut excerpt = self.excerpt_containing(range.clone())?;
5877        Some(
5878            excerpt
5879                .buffer()
5880                .bracket_ranges(excerpt.map_range_to_buffer(range))
5881                .filter_map(move |pair| {
5882                    let open_range =
5883                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5884                    let close_range =
5885                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5886                    excerpt
5887                        .contains_buffer_range(open_range.start..close_range.end)
5888                        .then(|| BracketMatch {
5889                            open_range: excerpt.map_range_from_buffer(open_range),
5890                            close_range: excerpt.map_range_from_buffer(close_range),
5891                            color_index: pair.color_index,
5892                            newline_only: pair.newline_only,
5893                            syntax_layer_depth: pair.syntax_layer_depth,
5894                        })
5895                })
5896                .map(BracketMatch::bracket_ranges),
5897        )
5898    }
5899
5900    pub fn redacted_ranges<'a, T: ToOffset>(
5901        &'a self,
5902        range: Range<T>,
5903        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5904    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5905        let range = range.start.to_offset(self)..range.end.to_offset(self);
5906        self.lift_buffer_metadata(range, move |buffer, range| {
5907            if redaction_enabled(buffer.file()) {
5908                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5909            } else {
5910                None
5911            }
5912        })
5913        .map(|(range, _, _)| range)
5914    }
5915
5916    pub fn runnable_ranges(
5917        &self,
5918        range: Range<Anchor>,
5919    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5920        let range = range.start.to_offset(self)..range.end.to_offset(self);
5921        self.lift_buffer_metadata(range, move |buffer, range| {
5922            Some(
5923                buffer
5924                    .runnable_ranges(range.clone())
5925                    .filter(move |runnable| {
5926                        runnable.run_range.start >= range.start
5927                            && runnable.run_range.end < range.end
5928                    })
5929                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5930            )
5931        })
5932        .map(|(run_range, runnable, _)| (run_range, runnable))
5933    }
5934
5935    pub fn line_indents(
5936        &self,
5937        start_row: MultiBufferRow,
5938        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5939    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5940        let max_point = self.max_point();
5941        let mut cursor = self.cursor::<Point, Point>();
5942        cursor.seek(&Point::new(start_row.0, 0));
5943        iter::from_fn(move || {
5944            let mut region = cursor.region()?;
5945            while !buffer_filter(&region.excerpt.buffer) {
5946                cursor.next();
5947                region = cursor.region()?;
5948            }
5949            let region = cursor.region()?;
5950            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5951            let buffer_start_row =
5952                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5953
5954            let buffer_end_row = if region.is_main_buffer
5955                && (region.has_trailing_newline || region.range.end == max_point)
5956            {
5957                region.buffer_range.end.row
5958            } else {
5959                region.buffer_range.end.row.saturating_sub(1)
5960            };
5961
5962            let line_indents = region
5963                .buffer
5964                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5965            let region_buffer_row = region.buffer_range.start.row;
5966            let region_row = region.range.start.row;
5967            let region_buffer = &region.excerpt.buffer;
5968            cursor.next();
5969            Some(line_indents.map(move |(buffer_row, indent)| {
5970                let row = region_row + (buffer_row - region_buffer_row);
5971                (MultiBufferRow(row), indent, region_buffer.as_ref())
5972            }))
5973        })
5974        .flatten()
5975    }
5976
5977    pub fn reversed_line_indents(
5978        &self,
5979        end_row: MultiBufferRow,
5980        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5981    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5982        let max_point = self.max_point();
5983        let mut cursor = self.cursor::<Point, Point>();
5984        cursor.seek(&Point::new(end_row.0, 0));
5985        iter::from_fn(move || {
5986            let mut region = cursor.region()?;
5987            while !buffer_filter(&region.excerpt.buffer) {
5988                cursor.prev();
5989                region = cursor.region()?;
5990            }
5991            let region = cursor.region()?;
5992
5993            let buffer_start_row = region.buffer_range.start.row;
5994            let buffer_end_row = if region.is_main_buffer
5995                && (region.has_trailing_newline || region.range.end == max_point)
5996            {
5997                region.buffer_range.end.row + 1
5998            } else {
5999                region.buffer_range.end.row
6000            };
6001
6002            let overshoot = end_row.0 - region.range.start.row;
6003            let buffer_end_row =
6004                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6005
6006            let line_indents = region
6007                .buffer
6008                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6009            let region_buffer_row = region.buffer_range.start.row;
6010            let region_row = region.range.start.row;
6011            let region_buffer = &region.excerpt.buffer;
6012            cursor.prev();
6013            Some(line_indents.map(move |(buffer_row, indent)| {
6014                let row = region_row + (buffer_row - region_buffer_row);
6015                (MultiBufferRow(row), indent, region_buffer.as_ref())
6016            }))
6017        })
6018        .flatten()
6019    }
6020
6021    pub async fn enclosing_indent(
6022        &self,
6023        mut target_row: MultiBufferRow,
6024    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6025        let max_row = MultiBufferRow(self.max_point().row);
6026        if target_row >= max_row {
6027            return None;
6028        }
6029
6030        let mut target_indent = self.line_indent_for_row(target_row);
6031
6032        // If the current row is at the start of an indented block, we want to return this
6033        // block as the enclosing indent.
6034        if !target_indent.is_line_empty() && target_row < max_row {
6035            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6036            if !next_line_indent.is_line_empty()
6037                && target_indent.raw_len() < next_line_indent.raw_len()
6038            {
6039                target_indent = next_line_indent;
6040                target_row.0 += 1;
6041            }
6042        }
6043
6044        const SEARCH_ROW_LIMIT: u32 = 25000;
6045        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6046        const YIELD_INTERVAL: u32 = 100;
6047
6048        let mut accessed_row_counter = 0;
6049
6050        // If there is a blank line at the current row, search for the next non indented lines
6051        if target_indent.is_line_empty() {
6052            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6053            let end =
6054                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6055
6056            let mut non_empty_line_above = None;
6057            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6058                if row < start {
6059                    break;
6060                }
6061                accessed_row_counter += 1;
6062                if accessed_row_counter == YIELD_INTERVAL {
6063                    accessed_row_counter = 0;
6064                    yield_now().await;
6065                }
6066                if !indent.is_line_empty() {
6067                    non_empty_line_above = Some((row, indent));
6068                    break;
6069                }
6070            }
6071
6072            let mut non_empty_line_below = None;
6073            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6074                if row > end {
6075                    break;
6076                }
6077                accessed_row_counter += 1;
6078                if accessed_row_counter == YIELD_INTERVAL {
6079                    accessed_row_counter = 0;
6080                    yield_now().await;
6081                }
6082                if !indent.is_line_empty() {
6083                    non_empty_line_below = Some((row, indent));
6084                    break;
6085                }
6086            }
6087
6088            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6089                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6090                    if above_indent.raw_len() >= below_indent.raw_len() {
6091                        (above_row, above_indent)
6092                    } else {
6093                        (below_row, below_indent)
6094                    }
6095                }
6096                (Some(above), None) => above,
6097                (None, Some(below)) => below,
6098                _ => return None,
6099            };
6100
6101            target_indent = indent;
6102            target_row = row;
6103        }
6104
6105        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6106        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6107
6108        let mut start_indent = None;
6109        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6110            if row < start {
6111                break;
6112            }
6113            accessed_row_counter += 1;
6114            if accessed_row_counter == YIELD_INTERVAL {
6115                accessed_row_counter = 0;
6116                yield_now().await;
6117            }
6118            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6119                start_indent = Some((row, indent));
6120                break;
6121            }
6122        }
6123        let (start_row, start_indent_size) = start_indent?;
6124
6125        let mut end_indent = (end, None);
6126        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6127            if row > end {
6128                break;
6129            }
6130            accessed_row_counter += 1;
6131            if accessed_row_counter == YIELD_INTERVAL {
6132                accessed_row_counter = 0;
6133                yield_now().await;
6134            }
6135            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6136                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6137                break;
6138            }
6139        }
6140        let (end_row, end_indent_size) = end_indent;
6141
6142        let indent = if let Some(end_indent_size) = end_indent_size {
6143            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6144                start_indent_size
6145            } else {
6146                end_indent_size
6147            }
6148        } else {
6149            start_indent_size
6150        };
6151
6152        Some((start_row..end_row, indent))
6153    }
6154
6155    pub fn indent_guides_in_range<T: ToPoint>(
6156        &self,
6157        range: Range<T>,
6158        ignore_disabled_for_language: bool,
6159        cx: &App,
6160    ) -> impl Iterator<Item = IndentGuide> {
6161        let range = range.start.to_point(self)..range.end.to_point(self);
6162        let start_row = MultiBufferRow(range.start.row);
6163        let end_row = MultiBufferRow(range.end.row);
6164
6165        let mut row_indents = self.line_indents(start_row, |buffer| {
6166            let settings =
6167                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6168            settings.indent_guides.enabled || ignore_disabled_for_language
6169        });
6170
6171        let mut result = Vec::new();
6172        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6173
6174        let mut prev_settings = None;
6175        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6176            if first_row > end_row {
6177                break;
6178            }
6179            let current_depth = indent_stack.len() as u32;
6180
6181            // Avoid retrieving the language settings repeatedly for every buffer row.
6182            if let Some((prev_buffer_id, _)) = &prev_settings
6183                && prev_buffer_id != &buffer.remote_id()
6184            {
6185                prev_settings.take();
6186            }
6187            let settings = &prev_settings
6188                .get_or_insert_with(|| {
6189                    (
6190                        buffer.remote_id(),
6191                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6192                    )
6193                })
6194                .1;
6195            let tab_size = settings.tab_size.get();
6196
6197            // When encountering empty, continue until found useful line indent
6198            // then add to the indent stack with the depth found
6199            let mut found_indent = false;
6200            let mut last_row = first_row;
6201            if line_indent.is_line_blank() {
6202                while !found_indent {
6203                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6204                        break;
6205                    };
6206                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6207                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6208                        break;
6209                    }
6210
6211                    if new_line_indent.is_line_blank() {
6212                        continue;
6213                    }
6214                    last_row = target_row.min(end_row);
6215                    line_indent = new_line_indent;
6216                    found_indent = true;
6217                    break;
6218                }
6219            } else {
6220                found_indent = true
6221            }
6222
6223            let depth = if found_indent {
6224                line_indent.len(tab_size) / tab_size
6225            } else {
6226                0
6227            };
6228
6229            match depth.cmp(&current_depth) {
6230                cmp::Ordering::Less => {
6231                    for _ in 0..(current_depth - depth) {
6232                        let mut indent = indent_stack.pop().unwrap();
6233                        if last_row != first_row {
6234                            // In this case, we landed on an empty row, had to seek forward,
6235                            // and discovered that the indent we where on is ending.
6236                            // This means that the last display row must
6237                            // be on line that ends this indent range, so we
6238                            // should display the range up to the first non-empty line
6239                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6240                        }
6241
6242                        result.push(indent)
6243                    }
6244                }
6245                cmp::Ordering::Greater => {
6246                    for next_depth in current_depth..depth {
6247                        indent_stack.push(IndentGuide {
6248                            buffer_id: buffer.remote_id(),
6249                            start_row: first_row,
6250                            end_row: last_row,
6251                            depth: next_depth,
6252                            tab_size,
6253                            settings: settings.indent_guides.clone(),
6254                        });
6255                    }
6256                }
6257                _ => {}
6258            }
6259
6260            for indent in indent_stack.iter_mut() {
6261                indent.end_row = last_row;
6262            }
6263        }
6264
6265        result.extend(indent_stack);
6266        result.into_iter()
6267    }
6268
6269    pub fn trailing_excerpt_update_count(&self) -> usize {
6270        self.trailing_excerpt_update_count
6271    }
6272
6273    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6274        self.point_to_buffer_offset(point)
6275            .and_then(|(buffer, _)| buffer.file())
6276    }
6277
6278    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6279        self.point_to_buffer_offset(offset)
6280            .and_then(|(buffer, offset)| buffer.language_at(offset))
6281    }
6282
6283    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6284        self.excerpts
6285            .first()
6286            .map(|excerpt| &excerpt.buffer)
6287            .map(|buffer| {
6288                language_settings(
6289                    buffer.language().map(|language| language.name()),
6290                    buffer.file(),
6291                    cx,
6292                )
6293            })
6294            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6295    }
6296
6297    pub fn language_settings_at<'a, T: ToOffset>(
6298        &'a self,
6299        point: T,
6300        cx: &'a App,
6301    ) -> Cow<'a, LanguageSettings> {
6302        let mut language = None;
6303        let mut file = None;
6304        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6305            language = buffer.language_at(offset);
6306            file = buffer.file();
6307        }
6308        language_settings(language.map(|l| l.name()), file, cx)
6309    }
6310
6311    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6312        self.point_to_buffer_offset(point)
6313            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6314    }
6315
6316    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6317        self.point_to_buffer_offset(point)
6318            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6319            .unwrap_or_default()
6320    }
6321
6322    pub fn language_indent_size_at<T: ToOffset>(
6323        &self,
6324        position: T,
6325        cx: &App,
6326    ) -> Option<IndentSize> {
6327        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6328        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6329    }
6330
6331    pub fn is_dirty(&self) -> bool {
6332        self.is_dirty
6333    }
6334
6335    pub fn has_deleted_file(&self) -> bool {
6336        self.has_deleted_file
6337    }
6338
6339    pub fn has_conflict(&self) -> bool {
6340        self.has_conflict
6341    }
6342
6343    pub fn has_diagnostics(&self) -> bool {
6344        self.excerpts
6345            .iter()
6346            .any(|excerpt| excerpt.buffer.has_diagnostics())
6347    }
6348
6349    pub fn diagnostic_group(
6350        &self,
6351        buffer_id: BufferId,
6352        group_id: usize,
6353    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6354        self.lift_buffer_metadata::<Point, _, _>(
6355            Point::zero()..self.max_point(),
6356            move |buffer, range| {
6357                if buffer.remote_id() != buffer_id {
6358                    return None;
6359                };
6360                Some(
6361                    buffer
6362                        .diagnostics_in_range(range, false)
6363                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6364                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6365                )
6366            },
6367        )
6368        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6369    }
6370
6371    pub fn diagnostics_in_range<'a, MBD>(
6372        &'a self,
6373        range: Range<MBD>,
6374    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6375    where
6376        MBD::TextDimension: 'a
6377            + text::ToOffset
6378            + text::FromAnchor
6379            + Sub<Output = MBD::TextDimension>
6380            + fmt::Debug
6381            + ops::Add<Output = MBD::TextDimension>
6382            + ops::AddAssign
6383            + Ord,
6384        MBD: MultiBufferDimension
6385            + Ord
6386            + Sub<Output = MBD::TextDimension>
6387            + ops::Add<MBD::TextDimension, Output = MBD>
6388            + ops::AddAssign<MBD::TextDimension>
6389            + 'a,
6390    {
6391        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6392            Some(
6393                buffer
6394                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6395                    .map(|entry| (entry.range, entry.diagnostic)),
6396            )
6397        })
6398        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6399    }
6400
6401    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6402        &'a self,
6403        range: Range<MBD>,
6404    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6405    where
6406        MBD: MultiBufferDimension
6407            + Ord
6408            + Sub<Output = MBD::TextDimension>
6409            + ops::Add<MBD::TextDimension, Output = MBD>
6410            + ops::AddAssign<MBD::TextDimension>,
6411        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6412            + ops::Add<Output = MBD::TextDimension>
6413            + text::ToOffset
6414            + text::FromAnchor
6415            + AddAssign<MBD::TextDimension>
6416            + Ord,
6417    {
6418        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6419            Some(
6420                buffer
6421                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6422                    .map(|entry| (entry.range, entry.diagnostic)),
6423            )
6424        })
6425        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6426    }
6427
6428    pub fn syntax_ancestor<T: ToOffset>(
6429        &self,
6430        range: Range<T>,
6431    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6432        let range = range.start.to_offset(self)..range.end.to_offset(self);
6433        let mut excerpt = self.excerpt_containing(range.clone())?;
6434        let node = excerpt
6435            .buffer()
6436            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6437        let node_range = node.byte_range();
6438        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6439        if !excerpt.contains_buffer_range(node_range.clone()) {
6440            return None;
6441        };
6442        Some((node, excerpt.map_range_from_buffer(node_range)))
6443    }
6444
6445    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6446        let (excerpt_id, _, buffer) = self.as_singleton()?;
6447        let outline = buffer.outline(theme);
6448        Some(Outline::new(
6449            outline
6450                .items
6451                .into_iter()
6452                .flat_map(|item| {
6453                    Some(OutlineItem {
6454                        depth: item.depth,
6455                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6456                        source_range_for_text: self
6457                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6458                        text: item.text,
6459                        highlight_ranges: item.highlight_ranges,
6460                        name_ranges: item.name_ranges,
6461                        body_range: item.body_range.and_then(|body_range| {
6462                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6463                        }),
6464                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6465                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6466                        }),
6467                    })
6468                })
6469                .collect(),
6470        ))
6471    }
6472
6473    pub fn symbols_containing<T: ToOffset>(
6474        &self,
6475        offset: T,
6476        theme: Option<&SyntaxTheme>,
6477    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6478        let anchor = self.anchor_before(offset);
6479        let excerpt @ &Excerpt {
6480            id: excerpt_id,
6481            buffer_id,
6482            ref buffer,
6483            ..
6484        } = self.excerpt(anchor.excerpt_id)?;
6485        if cfg!(debug_assertions) {
6486            match anchor.text_anchor.buffer_id {
6487                // we clearly are hitting this according to sentry, but in what situations can this occur?
6488                Some(anchor_buffer_id) => {
6489                    assert_eq!(
6490                        anchor_buffer_id, buffer_id,
6491                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6492                    )
6493                }
6494                None => assert!(anchor.is_max()),
6495            }
6496        };
6497        Some((
6498            buffer_id,
6499            buffer
6500                .symbols_containing(anchor.text_anchor, theme)
6501                .into_iter()
6502                .flat_map(|item| {
6503                    Some(OutlineItem {
6504                        depth: item.depth,
6505                        source_range_for_text: Anchor::range_in_buffer(
6506                            excerpt_id,
6507                            item.source_range_for_text,
6508                        ),
6509                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6510                        text: item.text,
6511                        highlight_ranges: item.highlight_ranges,
6512                        name_ranges: item.name_ranges,
6513                        body_range: item
6514                            .body_range
6515                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6516                        annotation_range: item
6517                            .annotation_range
6518                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6519                    })
6520                })
6521                .collect(),
6522        ))
6523    }
6524
6525    fn anchor_seek_target(&self, anchor: Anchor) -> AnchorSeekTarget {
6526        match anchor {
6527            Anchor::Min => AnchorSeekTarget::Min,
6528            Anchor::Max => AnchorSeekTarget::Max,
6529            Anchor::Text { path, .. } => {
6530                let path_key = self.path_for_anchor(anchor);
6531                let snapshot = self.buffer_for_path(path_key);
6532
6533                Some(AnchorSeekTarget::Text {
6534                    path_key: path_key.clone(),
6535                    anchor: anchor.text_anchor().unwrap(),
6536                    snapshot: snapshot.cloned(),
6537                })
6538            }
6539        }
6540    }
6541
6542    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6543        self.try_excerpt_locator_for_id(id)
6544            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6545    }
6546
6547    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6548        if id == ExcerptId::min() {
6549            Some(Locator::min_ref())
6550        } else if id == ExcerptId::max() {
6551            Some(Locator::max_ref())
6552        } else {
6553            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6554            if let Some(entry) = item
6555                && entry.id == id
6556            {
6557                return Some(&entry.locator);
6558            }
6559            None
6560        }
6561    }
6562
6563    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6564    fn excerpt_locators_for_ids(
6565        &self,
6566        ids: impl IntoIterator<Item = ExcerptId>,
6567    ) -> SmallVec<[Locator; 1]> {
6568        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6569        sorted_ids.sort_unstable();
6570        sorted_ids.dedup();
6571        let mut locators = SmallVec::new();
6572
6573        while sorted_ids.last() == Some(&ExcerptId::max()) {
6574            sorted_ids.pop();
6575            locators.push(Locator::max());
6576        }
6577
6578        let mut sorted_ids = sorted_ids.into_iter().peekable();
6579        locators.extend(
6580            sorted_ids
6581                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6582                .map(|_| Locator::min()),
6583        );
6584
6585        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6586        for id in sorted_ids {
6587            if cursor.seek_forward(&id, Bias::Left) {
6588                locators.push(cursor.item().unwrap().locator.clone());
6589            } else {
6590                panic!("invalid excerpt id {:?}", id);
6591            }
6592        }
6593
6594        locators.sort_unstable();
6595        locators
6596    }
6597
6598    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6599        Some(self.excerpt(excerpt_id)?.buffer_id)
6600    }
6601
6602    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6603        Some(&self.excerpt(excerpt_id)?.buffer)
6604    }
6605
6606    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6607        todo!()
6608    }
6609
6610    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6611        self.path_keys_by_buffer.get(&buffer_id)
6612    }
6613
6614    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6615        self.buffer_for_path(self.path_keys_by_buffer.get(&id)?)
6616    }
6617
6618    pub fn try_path_for_anchor(&self, anchor: Anchor) -> Option<PathKey> {
6619        match anchor {
6620            Anchor::Min => Some(
6621                self.excerpts
6622                    .first()
6623                    .map(|excerpt| excerpt.path_key.clone())
6624                    .unwrap_or(PathKey::min()),
6625            ),
6626            Anchor::Max => Some(
6627                self.excerpts
6628                    .last()
6629                    .map(|excerpt| excerpt.path_key.clone())
6630                    .unwrap_or(PathKey::min()),
6631            ),
6632            Anchor::Text { path, .. } => self.path_keys_by_index.get(&path).cloned(),
6633        }
6634    }
6635
6636    pub fn path_for_anchor(&self, anchor: Anchor) -> PathKey {
6637        self.try_path_for_anchor(anchor)
6638            .expect("invalid anchor: path was never added to multibuffer")
6639    }
6640
6641    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6642        let mut cursor = self
6643            .excerpts
6644            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6645        let locator = self.excerpt_locator_for_id(excerpt_id);
6646        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6647        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6648            sought_exact = true;
6649            cursor.prev();
6650        } else if excerpt_id == ExcerptId::min() {
6651            sought_exact = true;
6652        }
6653        if sought_exact {
6654            let start = cursor.start().1;
6655            let end = cursor.end().1;
6656            let mut diff_transforms = self
6657                .diff_transforms
6658                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6659            diff_transforms.seek(&start, Bias::Left);
6660            let overshoot = start - diff_transforms.start().0;
6661            let start = diff_transforms.start().1 + overshoot;
6662            diff_transforms.seek(&end, Bias::Right);
6663            let overshoot = end - diff_transforms.start().0;
6664            let end = diff_transforms.start().1 + overshoot;
6665            Some(start.0..end.0)
6666        } else {
6667            None
6668        }
6669    }
6670
6671    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6672    /// to have the latest excerpt id for the one passed in and will also remap
6673    /// `ExcerptId::max()` to the corresponding excertp ID.
6674    ///
6675    /// Callers of this function should generally use the resulting excerpt's `id` field
6676    /// afterwards.
6677    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6678        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6679        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
6680        let (_, _, item) =
6681            self.excerpts
6682                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
6683        if let Some(excerpt) = item
6684            && excerpt.id == excerpt_id
6685        {
6686            return Some(excerpt);
6687        } else if item.is_none() && excerpt_id == ExcerptId::max() {
6688            return self.excerpts.last();
6689        }
6690        None
6691    }
6692
6693    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6694    pub fn excerpt_containing<T: ToOffset>(
6695        &self,
6696        range: Range<T>,
6697    ) -> Option<MultiBufferExcerpt<'_>> {
6698        let range = range.start.to_offset(self)..range.end.to_offset(self);
6699        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6700        cursor.seek(&range.start);
6701
6702        let start_excerpt = cursor.excerpt()?;
6703        if range.end != range.start {
6704            cursor.seek_forward(&range.end);
6705            if cursor.excerpt()?.id != start_excerpt.id {
6706                return None;
6707            }
6708        }
6709
6710        cursor.seek_to_start_of_current_excerpt();
6711        let region = cursor.region()?;
6712        let offset = region.range.start;
6713        let buffer_offset = start_excerpt.buffer_start_offset();
6714        let excerpt_offset = *cursor.excerpts.start();
6715        Some(MultiBufferExcerpt {
6716            diff_transforms: cursor.diff_transforms,
6717            excerpt: start_excerpt,
6718            offset,
6719            buffer_offset,
6720            excerpt_offset,
6721        })
6722    }
6723
6724    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6725        if let Some(id) = anchor.text_anchor.buffer_id {
6726            return Some(id);
6727        }
6728        let excerpt = self.excerpt_containing(anchor..anchor)?;
6729        Some(excerpt.buffer_id())
6730    }
6731
6732    pub fn selections_in_range<'a>(
6733        &'a self,
6734        range: &'a Range<Anchor>,
6735        include_local: bool,
6736    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6737        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6738        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6739        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6740        cursor.seek(start_locator, Bias::Left);
6741        cursor
6742            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6743            .flat_map(move |excerpt| {
6744                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6745                if excerpt.id == range.start.excerpt_id {
6746                    query_range.start = range.start.text_anchor;
6747                }
6748                if excerpt.id == range.end.excerpt_id {
6749                    query_range.end = range.end.text_anchor;
6750                }
6751
6752                excerpt
6753                    .buffer
6754                    .selections_in_range(query_range, include_local)
6755                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6756                        selections.map(move |selection| {
6757                            let mut start = Anchor::text(excerpt.id, selection.start);
6758                            let mut end = Anchor::text(excerpt.id, selection.end);
6759                            if range.start.cmp(&start, self).is_gt() {
6760                                start = range.start;
6761                            }
6762                            if range.end.cmp(&end, self).is_lt() {
6763                                end = range.end;
6764                            }
6765
6766                            (
6767                                replica_id,
6768                                line_mode,
6769                                cursor_shape,
6770                                Selection {
6771                                    id: selection.id,
6772                                    start,
6773                                    end,
6774                                    reversed: selection.reversed,
6775                                    goal: selection.goal,
6776                                },
6777                            )
6778                        })
6779                    })
6780            })
6781    }
6782
6783    pub fn show_headers(&self) -> bool {
6784        self.show_headers
6785    }
6786
6787    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6788        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6789    }
6790
6791    pub fn all_diff_hunks_expanded(&self) -> bool {
6792        self.all_diff_hunks_expanded
6793    }
6794
6795    /// Visually annotates a position or range with the `Debug` representation of a value. The
6796    /// callsite of this function is used as a key - previous annotations will be removed.
6797    #[cfg(debug_assertions)]
6798    #[track_caller]
6799    pub fn debug<V, R>(&self, ranges: &R, value: V)
6800    where
6801        R: debug::ToMultiBufferDebugRanges,
6802        V: std::fmt::Debug,
6803    {
6804        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6805    }
6806
6807    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6808    /// debug annotations with the same key will be removed. The key is also used to determine the
6809    /// annotation's color.
6810    #[cfg(debug_assertions)]
6811    #[track_caller]
6812    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6813    where
6814        K: std::hash::Hash + 'static,
6815        R: debug::ToMultiBufferDebugRanges,
6816        V: std::fmt::Debug,
6817    {
6818        let text_ranges = ranges
6819            .to_multi_buffer_debug_ranges(self)
6820            .into_iter()
6821            .flat_map(|range| {
6822                self.range_to_buffer_ranges(range.start..=range.end)
6823                    .into_iter()
6824                    .map(|(buffer, range, _excerpt_id)| {
6825                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6826                    })
6827            })
6828            .collect();
6829        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6830            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6831        });
6832    }
6833
6834    fn excerpt_edits_for_diff_change(
6835        &self,
6836        buffer_state: &BufferState,
6837        diff_change_range: Range<usize>,
6838    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6839        let mut excerpt_edits = Vec::new();
6840        for locator in &buffer_state.excerpts {
6841            let mut cursor = self
6842                .excerpts
6843                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6844            cursor.seek_forward(&Some(locator), Bias::Left);
6845            if let Some(excerpt) = cursor.item()
6846                && excerpt.locator == *locator
6847            {
6848                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6849                if diff_change_range.end < excerpt_buffer_range.start
6850                    || diff_change_range.start > excerpt_buffer_range.end
6851                {
6852                    continue;
6853                }
6854                let excerpt_start = cursor.start().1;
6855                let excerpt_len = excerpt.text_summary.len;
6856                let diff_change_start_in_excerpt = diff_change_range
6857                    .start
6858                    .saturating_sub(excerpt_buffer_range.start);
6859                let diff_change_end_in_excerpt = diff_change_range
6860                    .end
6861                    .saturating_sub(excerpt_buffer_range.start);
6862                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6863                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6864                excerpt_edits.push(Edit {
6865                    old: edit_start..edit_end,
6866                    new: edit_start..edit_end,
6867                });
6868            }
6869        }
6870        excerpt_edits
6871    }
6872
6873    fn excerpt_ranges_for_path(
6874        &self,
6875        path_key: &PathKey,
6876    ) -> impl Iterator<Item = ExcerptRange<text::Anchor>> {
6877        todo!()
6878    }
6879}
6880
6881#[cfg(any(test, feature = "test-support"))]
6882impl MultiBufferSnapshot {
6883    pub fn random_byte_range(
6884        &self,
6885        start_offset: MultiBufferOffset,
6886        rng: &mut impl rand::Rng,
6887    ) -> Range<MultiBufferOffset> {
6888        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6889        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6890        start..end
6891    }
6892
6893    #[cfg(any(test, feature = "test-support"))]
6894    fn check_invariants(&self) {
6895        let excerpts = self.excerpts.items(());
6896        let excerpt_ids = self.excerpt_ids.items(());
6897
6898        for (ix, excerpt) in excerpts.iter().enumerate() {
6899            if ix == 0 {
6900                if excerpt.locator <= Locator::min() {
6901                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6902                }
6903            } else if excerpt.locator <= excerpts[ix - 1].locator {
6904                panic!("excerpts are out-of-order: {:?}", excerpts);
6905            }
6906        }
6907
6908        for (ix, entry) in excerpt_ids.iter().enumerate() {
6909            if ix == 0 {
6910                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6911                    panic!("invalid first excerpt id {:?}", entry.id);
6912                }
6913            } else if entry.id <= excerpt_ids[ix - 1].id {
6914                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6915            }
6916        }
6917
6918        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6919            panic!(
6920                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6921                self.excerpts.summary().text,
6922                self.diff_transforms.summary().input,
6923                self.diff_transforms.items(()),
6924            );
6925        }
6926
6927        let mut prev_transform: Option<&DiffTransform> = None;
6928        for item in self.diff_transforms.iter() {
6929            if let DiffTransform::BufferContent {
6930                summary,
6931                inserted_hunk_info,
6932            } = item
6933            {
6934                if let Some(DiffTransform::BufferContent {
6935                    inserted_hunk_info: prev_inserted_hunk_info,
6936                    ..
6937                }) = prev_transform
6938                    && *inserted_hunk_info == *prev_inserted_hunk_info
6939                {
6940                    panic!(
6941                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6942                        self.diff_transforms.items(())
6943                    );
6944                }
6945                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6946                    panic!("empty buffer content transform");
6947                }
6948            }
6949            prev_transform = Some(item);
6950        }
6951    }
6952}
6953
6954impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6955where
6956    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6957    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6958{
6959    #[instrument(skip_all)]
6960    fn seek(&mut self, position: &MBD) {
6961        let position = OutputDimension(*position);
6962        self.cached_region.take();
6963        self.diff_transforms.seek(&position, Bias::Right);
6964        if self.diff_transforms.item().is_none()
6965            && self.diff_transforms.start().output_dimension == position
6966        {
6967            self.diff_transforms.prev();
6968        }
6969
6970        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6971        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6972            let overshoot = position - self.diff_transforms.start().output_dimension;
6973            excerpt_position += overshoot;
6974        }
6975
6976        self.excerpts.seek(&excerpt_position, Bias::Right);
6977        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6978            self.excerpts.prev();
6979        }
6980    }
6981
6982    fn seek_forward(&mut self, position: &MBD) {
6983        let position = OutputDimension(*position);
6984        self.cached_region.take();
6985        self.diff_transforms.seek_forward(&position, Bias::Right);
6986        if self.diff_transforms.item().is_none()
6987            && self.diff_transforms.start().output_dimension == position
6988        {
6989            self.diff_transforms.prev();
6990        }
6991
6992        let overshoot = position - self.diff_transforms.start().output_dimension;
6993        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6994        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6995            excerpt_position += overshoot;
6996        }
6997
6998        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6999        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7000            self.excerpts.prev();
7001        }
7002    }
7003
7004    fn next_excerpt(&mut self) {
7005        self.excerpts.next();
7006        self.seek_to_start_of_current_excerpt();
7007    }
7008
7009    fn prev_excerpt(&mut self) {
7010        self.excerpts.prev();
7011        self.seek_to_start_of_current_excerpt();
7012    }
7013
7014    fn seek_to_start_of_current_excerpt(&mut self) {
7015        self.cached_region.take();
7016
7017        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7018            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7019            && self.diff_transforms.next_item().is_some()
7020        {
7021            self.diff_transforms.next();
7022        }
7023    }
7024
7025    fn next_excerpt_forwards(&mut self) {
7026        self.excerpts.next();
7027        self.seek_to_start_of_current_excerpt_forward();
7028    }
7029
7030    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7031        self.cached_region.take();
7032
7033        if self
7034            .diff_transforms
7035            .seek_forward(self.excerpts.start(), Bias::Left)
7036            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7037            && self.diff_transforms.next_item().is_some()
7038        {
7039            self.diff_transforms.next();
7040        }
7041    }
7042
7043    fn next(&mut self) {
7044        self.cached_region.take();
7045        match self
7046            .diff_transforms
7047            .end()
7048            .excerpt_dimension
7049            .cmp(&self.excerpts.end())
7050        {
7051            cmp::Ordering::Less => self.diff_transforms.next(),
7052            cmp::Ordering::Greater => self.excerpts.next(),
7053            cmp::Ordering::Equal => {
7054                self.diff_transforms.next();
7055                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7056                    || self.diff_transforms.item().is_none()
7057                {
7058                    self.excerpts.next();
7059                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7060                    self.diff_transforms.item()
7061                    && self
7062                        .excerpts
7063                        .item()
7064                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7065                {
7066                    self.excerpts.next();
7067                }
7068            }
7069        }
7070    }
7071
7072    fn prev(&mut self) {
7073        self.cached_region.take();
7074        match self
7075            .diff_transforms
7076            .start()
7077            .excerpt_dimension
7078            .cmp(self.excerpts.start())
7079        {
7080            cmp::Ordering::Less => self.excerpts.prev(),
7081            cmp::Ordering::Greater => self.diff_transforms.prev(),
7082            cmp::Ordering::Equal => {
7083                self.diff_transforms.prev();
7084                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7085                    || self.diff_transforms.item().is_none()
7086                {
7087                    self.excerpts.prev();
7088                }
7089            }
7090        }
7091    }
7092
7093    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7094        self.cached_region
7095            .get_or_init(|| self.build_region())
7096            .as_ref()
7097    }
7098
7099    fn is_at_start_of_excerpt(&mut self) -> bool {
7100        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7101            return false;
7102        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7103            return true;
7104        }
7105
7106        self.diff_transforms.prev();
7107        let prev_transform = self.diff_transforms.item();
7108        self.diff_transforms.next();
7109
7110        prev_transform.is_none_or(|next_transform| {
7111            matches!(next_transform, DiffTransform::BufferContent { .. })
7112        })
7113    }
7114
7115    fn is_at_end_of_excerpt(&self) -> bool {
7116        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7117            return false;
7118        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7119            || self.diff_transforms.item().is_none()
7120        {
7121            return true;
7122        }
7123
7124        let next_transform = self.diff_transforms.next_item();
7125        next_transform.is_none_or(|next_transform| match next_transform {
7126            DiffTransform::BufferContent { .. } => true,
7127            DiffTransform::DeletedHunk { hunk_info, .. } => self
7128                .excerpts
7129                .item()
7130                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7131        })
7132    }
7133
7134    fn main_buffer_position(&self) -> Option<BD> {
7135        let excerpt = self.excerpts.item()?;
7136        let buffer = &excerpt.buffer;
7137        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7138        let mut buffer_start = buffer_context_start;
7139        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7140        buffer_start += overshoot;
7141        Some(buffer_start)
7142    }
7143
7144    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7145        let excerpt = self.excerpts.item()?;
7146        match self.diff_transforms.item()? {
7147            DiffTransform::DeletedHunk {
7148                buffer_id,
7149                base_text_byte_range,
7150                has_trailing_newline,
7151                hunk_info,
7152                ..
7153            } => {
7154                let diff = self.diffs.get(buffer_id)?;
7155                let buffer = diff.base_text();
7156                let mut rope_cursor = buffer.as_rope().cursor(0);
7157                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7158                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7159                let mut buffer_end = buffer_start;
7160                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7161                let start = self.diff_transforms.start().output_dimension.0;
7162                let end = self.diff_transforms.end().output_dimension.0;
7163                Some(MultiBufferRegion {
7164                    buffer,
7165                    excerpt,
7166                    has_trailing_newline: *has_trailing_newline,
7167                    is_main_buffer: false,
7168                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7169                        hunk_info.hunk_secondary_status,
7170                    )),
7171                    buffer_range: buffer_start..buffer_end,
7172                    range: start..end,
7173                })
7174            }
7175            DiffTransform::BufferContent {
7176                inserted_hunk_info, ..
7177            } => {
7178                let buffer = &excerpt.buffer;
7179                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7180
7181                let mut start = self.diff_transforms.start().output_dimension.0;
7182                let mut buffer_start = buffer_context_start;
7183                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7184                    let overshoot =
7185                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7186                    start += overshoot;
7187                } else {
7188                    let overshoot =
7189                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7190                    buffer_start += overshoot;
7191                }
7192
7193                let mut end;
7194                let mut buffer_end;
7195                let has_trailing_newline;
7196                let transform_end = self.diff_transforms.end();
7197                if transform_end.excerpt_dimension < self.excerpts.end() {
7198                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7199                    end = transform_end.output_dimension.0;
7200                    buffer_end = buffer_context_start;
7201                    buffer_end += overshoot;
7202                    has_trailing_newline = false;
7203                } else {
7204                    let overshoot =
7205                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7206                    end = self.diff_transforms.start().output_dimension.0;
7207                    end += overshoot;
7208                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7209                    has_trailing_newline = excerpt.has_trailing_newline;
7210                };
7211
7212                let diff_hunk_status = inserted_hunk_info.map(|info| {
7213                    if info.is_logically_deleted {
7214                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7215                    } else {
7216                        DiffHunkStatus::added(info.hunk_secondary_status)
7217                    }
7218                });
7219
7220                Some(MultiBufferRegion {
7221                    buffer,
7222                    excerpt,
7223                    has_trailing_newline,
7224                    is_main_buffer: true,
7225                    diff_hunk_status,
7226                    buffer_range: buffer_start..buffer_end,
7227                    range: start..end,
7228                })
7229            }
7230        }
7231    }
7232
7233    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7234        let excerpt = self.excerpts.item()?;
7235        match self.diff_transforms.item()? {
7236            &DiffTransform::DeletedHunk { .. } => {
7237                let start = self.diff_transforms.start().output_dimension.0;
7238                let end = self.diff_transforms.end().output_dimension.0;
7239                Some((excerpt, start..end))
7240            }
7241            DiffTransform::BufferContent { .. } => {
7242                let mut start = self.diff_transforms.start().output_dimension.0;
7243                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7244                    let overshoot =
7245                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7246                    start += overshoot;
7247                }
7248
7249                let mut end;
7250                let transform_end = self.diff_transforms.end();
7251                if transform_end.excerpt_dimension < self.excerpts.end() {
7252                    end = transform_end.output_dimension.0;
7253                } else {
7254                    let overshoot =
7255                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7256                    end = self.diff_transforms.start().output_dimension.0;
7257                    end += overshoot;
7258                };
7259
7260                Some((excerpt, start..end))
7261            }
7262        }
7263    }
7264
7265    fn excerpt(&self) -> Option<&'a Excerpt> {
7266        self.excerpts.item()
7267    }
7268}
7269
7270impl Excerpt {
7271    fn new(
7272        path_key: PathKey,
7273        buffer: Arc<BufferSnapshot>,
7274        range: ExcerptRange<text::Anchor>,
7275        has_trailing_newline: bool,
7276    ) -> Self {
7277        Excerpt {
7278            path_key,
7279            max_buffer_row: range.context.end.to_point(&buffer).row,
7280            text_summary: buffer
7281                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7282            buffer,
7283            range,
7284            has_trailing_newline,
7285        }
7286    }
7287
7288    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7289        let content_start = self.range.context.start.to_offset(&self.buffer);
7290        let chunks_start = content_start + range.start;
7291        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7292
7293        let has_footer = self.has_trailing_newline
7294            && range.start <= self.text_summary.len
7295            && range.end > self.text_summary.len;
7296
7297        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7298
7299        ExcerptChunks {
7300            content_chunks,
7301            has_footer,
7302        }
7303    }
7304
7305    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7306        let content_start = self.range.context.start.to_offset(&self.buffer);
7307        let chunks_start = content_start + range.start;
7308        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7309        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7310        excerpt_chunks.has_footer = self.has_trailing_newline
7311            && range.start <= self.text_summary.len
7312            && range.end > self.text_summary.len;
7313    }
7314
7315    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7316        if text_anchor
7317            .cmp(&self.range.context.start, &self.buffer)
7318            .is_lt()
7319        {
7320            self.range.context.start
7321        } else if text_anchor
7322            .cmp(&self.range.context.end, &self.buffer)
7323            .is_gt()
7324        {
7325            self.range.context.end
7326        } else {
7327            text_anchor
7328        }
7329    }
7330
7331    // todo!() this always rejects min/max right now, is that right?
7332    pub(crate) fn contains(&self, anchor: &Anchor) -> bool {
7333        let Some((path, text_anchor, _)) = anchor.text_anchor() else {
7334            return false;
7335        };
7336        self.path_key_index == path && self.range.contains(&text_anchor, &self.buffer)
7337    }
7338
7339    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7340    fn buffer_start_offset(&self) -> BufferOffset {
7341        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7342    }
7343
7344    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7345    fn buffer_end_offset(&self) -> BufferOffset {
7346        self.buffer_start_offset() + self.text_summary.len
7347    }
7348}
7349
7350impl PartialEq for Excerpt {
7351    fn eq(&self, other: &Self) -> bool {
7352        self.buffer.remote_id() == other.buffer.remote_id()
7353            && self.range.context == other.range.context
7354    }
7355}
7356
7357impl<'a> MultiBufferExcerpt<'a> {
7358    pub fn id(&self) -> ExcerptId {
7359        self.excerpt.id
7360    }
7361
7362    pub fn buffer_id(&self) -> BufferId {
7363        self.excerpt.buffer_id
7364    }
7365
7366    pub fn start_anchor(&self) -> Anchor {
7367        Anchor::text(self.excerpt.id, self.excerpt.range.context.start)
7368    }
7369
7370    pub fn end_anchor(&self) -> Anchor {
7371        Anchor::text(self.excerpt.id, self.excerpt.range.context.end)
7372    }
7373
7374    pub fn buffer(&self) -> &'a BufferSnapshot {
7375        &self.excerpt.buffer
7376    }
7377
7378    pub fn buffer_range(&self) -> Range<BufferOffset> {
7379        self.buffer_offset
7380            ..BufferOffset(
7381                self.excerpt
7382                    .range
7383                    .context
7384                    .end
7385                    .to_offset(&self.excerpt.buffer.text),
7386            )
7387    }
7388
7389    pub fn start_offset(&self) -> MultiBufferOffset {
7390        self.offset
7391    }
7392
7393    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7394    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7395        self.map_range_to_buffer(offset..offset).start
7396    }
7397
7398    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7399    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7400        self.diff_transforms
7401            .seek(&OutputDimension(range.start), Bias::Right);
7402        let start = self.map_offset_to_buffer_internal(range.start);
7403        let end = if range.end > range.start {
7404            self.diff_transforms
7405                .seek_forward(&OutputDimension(range.end), Bias::Right);
7406            self.map_offset_to_buffer_internal(range.end)
7407        } else {
7408            start
7409        };
7410        start..end
7411    }
7412
7413    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7414        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7415        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7416            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7417        };
7418        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7419        self.buffer_offset + offset_in_excerpt
7420    }
7421
7422    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7423    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7424        self.map_range_from_buffer(buffer_offset..buffer_offset)
7425            .start
7426    }
7427
7428    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7429    pub fn map_range_from_buffer(
7430        &mut self,
7431        buffer_range: Range<BufferOffset>,
7432    ) -> Range<MultiBufferOffset> {
7433        if buffer_range.start < self.buffer_offset {
7434            log::warn!(
7435                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7436            );
7437            return self.offset..self.offset;
7438        }
7439        let overshoot = buffer_range.start - self.buffer_offset;
7440        let excerpt_offset = self.excerpt_offset + overshoot;
7441        let excerpt_seek_dim = excerpt_offset;
7442        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7443        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7444            log::warn!(
7445                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7446            );
7447            return self.offset..self.offset;
7448        }
7449        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7450        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7451
7452        let end = if buffer_range.start < buffer_range.end {
7453            let overshoot = buffer_range.end - self.buffer_offset;
7454            let excerpt_offset = self.excerpt_offset + overshoot;
7455            let excerpt_seek_dim = excerpt_offset;
7456            self.diff_transforms
7457                .seek_forward(&excerpt_seek_dim, Bias::Right);
7458            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7459            // todo(lw): Clamp end to the excerpt boundaries
7460            self.diff_transforms.start().output_dimension.0 + overshoot
7461        } else {
7462            start
7463        };
7464
7465        start..end
7466    }
7467
7468    /// Returns true if the entirety of the given range is in the buffer's excerpt
7469    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7470        range.start >= self.excerpt.buffer_start_offset()
7471            && range.end <= self.excerpt.buffer_end_offset()
7472    }
7473
7474    /// Returns true if any part of the given range is in the buffer's excerpt
7475    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7476        range.start <= self.excerpt.buffer_end_offset()
7477            && range.end >= self.excerpt.buffer_start_offset()
7478    }
7479
7480    pub fn max_buffer_row(&self) -> u32 {
7481        self.excerpt.max_buffer_row
7482    }
7483}
7484
7485impl fmt::Debug for Excerpt {
7486    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7487        f.debug_struct("Excerpt")
7488            .field("path_key", &self.path_key)
7489            .field("range", &self.range)
7490            .field("text_summary", &self.text_summary)
7491            .field("has_trailing_newline", &self.has_trailing_newline)
7492            .finish()
7493    }
7494}
7495
7496impl sum_tree::Item for Excerpt {
7497    type Summary = ExcerptSummary;
7498
7499    fn summary(&self, _cx: ()) -> Self::Summary {
7500        let mut text = self.text_summary;
7501        if self.has_trailing_newline {
7502            text += TextSummary::from("\n");
7503        }
7504        ExcerptSummary {
7505            path_key: self.path_key,
7506            max_anchor: self.range.context.end,
7507            widest_line_number: self.max_buffer_row,
7508            text: text.into(),
7509            count: 1,
7510        }
7511    }
7512}
7513
7514impl DiffTransform {
7515    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7516        match self {
7517            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7518            DiffTransform::BufferContent {
7519                inserted_hunk_info, ..
7520            } => *inserted_hunk_info,
7521        }
7522    }
7523}
7524
7525impl sum_tree::Item for DiffTransform {
7526    type Summary = DiffTransformSummary;
7527
7528    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7529        match self {
7530            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7531                input: *summary,
7532                output: *summary,
7533            },
7534            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7535                input: MBTextSummary::default(),
7536                output: summary.into(),
7537            },
7538        }
7539    }
7540}
7541
7542impl DiffTransformSummary {
7543    fn excerpt_len(&self) -> ExcerptOffset {
7544        ExcerptDimension(self.input.len)
7545    }
7546}
7547
7548impl sum_tree::ContextLessSummary for DiffTransformSummary {
7549    fn zero() -> Self {
7550        DiffTransformSummary {
7551            input: MBTextSummary::default(),
7552            output: MBTextSummary::default(),
7553        }
7554    }
7555
7556    fn add_summary(&mut self, other: &Self) {
7557        self.input += other.input;
7558        self.output += other.output;
7559    }
7560}
7561
7562impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7563    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7564        PathKey::min()
7565    }
7566
7567    fn add_summary(
7568        &mut self,
7569        summary: &'_ ExcerptSummary,
7570        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7571    ) {
7572        *self = summary.path_key.clone();
7573    }
7574}
7575
7576impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7577    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7578        MultiBufferOffset::ZERO
7579    }
7580
7581    fn add_summary(
7582        &mut self,
7583        summary: &'_ ExcerptSummary,
7584        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7585    ) {
7586        self += summary.text.len
7587    }
7588}
7589
7590impl sum_tree::ContextLessSummary for ExcerptSummary {
7591    fn zero() -> Self {
7592        Self::min()
7593    }
7594
7595    fn add_summary(&mut self, summary: &Self) {
7596        debug_assert!(
7597            summary.path_key >= self.path_key,
7598            "Path keys must be in ascending order: {:?} > {:?}",
7599            summary.path_key,
7600            self.path_key
7601        );
7602
7603        self.path_key = summary.path_key.clone();
7604        self.max_anchor = summary.max_anchor;
7605        self.text += summary.text;
7606        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7607        self.count += summary.count;
7608    }
7609}
7610
7611// todo!() should this take a lifetime?
7612enum AnchorSeekTarget {
7613    Min,
7614    Max,
7615    Text {
7616        path_key: PathKey,
7617        anchor: text::Anchor,
7618        // None when the buffer no longer exists in the multibuffer
7619        snapshot: Option<BufferSnapshot>,
7620    },
7621}
7622
7623impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7624    fn cmp(
7625        &self,
7626        cursor_location: &ExcerptSummary,
7627        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7628    ) -> cmp::Ordering {
7629        match self {
7630            AnchorSeekTarget::Min => Ordering::Less,
7631            AnchorSeekTarget::Max => Ordering::Greater,
7632            AnchorSeekTarget::Text {
7633                path_key,
7634                anchor,
7635                snapshot,
7636            } => {
7637                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7638                if path_comparison.is_ne() {
7639                    path_comparison
7640                } else if let Some(snapshot) = snapshot {
7641                    anchor.cmp(&cursor_location.max_anchor, snapshot)
7642                } else {
7643                    // shouldn't happen because we expect this buffer not to have any excerpts
7644                    Ordering::Equal
7645                }
7646            }
7647        }
7648    }
7649}
7650
7651impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7652    fn cmp(
7653        &self,
7654        cursor_location: &ExcerptSummary,
7655        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7656    ) -> cmp::Ordering {
7657        todo!()
7658    }
7659}
7660
7661impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7662where
7663    MBD: MultiBufferDimension + Default,
7664{
7665    fn zero(_: ()) -> Self {
7666        ExcerptDimension(MBD::default())
7667    }
7668
7669    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7670        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7671    }
7672}
7673
7674#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7675struct OutputDimension<T>(T);
7676
7677impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7678    fn eq(&self, other: &T) -> bool {
7679        self.0 == *other
7680    }
7681}
7682
7683impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7684    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7685        self.0.partial_cmp(other)
7686    }
7687}
7688
7689impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7690where
7691    T: ops::Sub<U, Output = R>,
7692{
7693    type Output = R;
7694
7695    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7696        self.0 - other.0
7697    }
7698}
7699
7700impl<R, T, U> ops::Add<U> for OutputDimension<T>
7701where
7702    T: ops::Add<U, Output = R>,
7703{
7704    type Output = OutputDimension<R>;
7705
7706    fn add(self, other: U) -> Self::Output {
7707        OutputDimension(self.0 + other)
7708    }
7709}
7710
7711impl<T, U> AddAssign<U> for OutputDimension<T>
7712where
7713    T: AddAssign<U>,
7714{
7715    fn add_assign(&mut self, other: U) {
7716        self.0 += other;
7717    }
7718}
7719
7720impl<T, U> SubAssign<U> for OutputDimension<T>
7721where
7722    T: SubAssign<U>,
7723{
7724    fn sub_assign(&mut self, other: U) {
7725        self.0 -= other;
7726    }
7727}
7728
7729#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7730struct ExcerptDimension<T>(T);
7731
7732impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7733    fn eq(&self, other: &T) -> bool {
7734        self.0 == *other
7735    }
7736}
7737
7738impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7739    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7740        self.0.partial_cmp(other)
7741    }
7742}
7743
7744impl ExcerptOffset {
7745    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7746        self.0.saturating_sub(other.0)
7747    }
7748}
7749
7750impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7751where
7752    T: ops::Sub<U, Output = R>,
7753{
7754    type Output = R;
7755
7756    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7757        self.0 - other.0
7758    }
7759}
7760
7761impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7762where
7763    T: ops::Add<U, Output = R>,
7764{
7765    type Output = ExcerptDimension<R>;
7766
7767    fn add(self, other: U) -> Self::Output {
7768        ExcerptDimension(self.0 + other)
7769    }
7770}
7771
7772impl<T, U> AddAssign<U> for ExcerptDimension<T>
7773where
7774    T: AddAssign<U>,
7775{
7776    fn add_assign(&mut self, other: U) {
7777        self.0 += other;
7778    }
7779}
7780
7781impl<T, U> SubAssign<U> for ExcerptDimension<T>
7782where
7783    T: SubAssign<U>,
7784{
7785    fn sub_assign(&mut self, other: U) {
7786        self.0 -= other;
7787    }
7788}
7789
7790impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7791    fn zero(_: ()) -> Self {
7792        MultiBufferOffset::ZERO
7793    }
7794
7795    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7796        *self += summary.output.len;
7797    }
7798}
7799
7800impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7801    for ExcerptDimension<MBD>
7802where
7803    MBD: MultiBufferDimension + Ord,
7804{
7805    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7806        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7807    }
7808}
7809
7810impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7811    for ExcerptDimension<MBD>
7812where
7813    MBD: MultiBufferDimension + Ord,
7814{
7815    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7816        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7817    }
7818}
7819
7820impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7821    for ExcerptDimension<MBD>
7822{
7823    fn zero(_: ()) -> Self {
7824        ExcerptDimension(MBD::default())
7825    }
7826
7827    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7828        self.0.add_mb_text_summary(&summary.input)
7829    }
7830}
7831
7832impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7833    for OutputDimension<MBD>
7834where
7835    MBD: MultiBufferDimension + Ord,
7836{
7837    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7838        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7839    }
7840}
7841
7842impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7843    for OutputDimension<MBD>
7844{
7845    fn zero(_: ()) -> Self {
7846        OutputDimension(MBD::default())
7847    }
7848
7849    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7850        self.0.add_mb_text_summary(&summary.output)
7851    }
7852}
7853
7854impl MultiBufferRows<'_> {
7855    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7856        self.point = Point::new(row, 0);
7857        self.cursor.seek(&self.point);
7858    }
7859}
7860
7861impl Iterator for MultiBufferRows<'_> {
7862    type Item = RowInfo;
7863
7864    fn next(&mut self) -> Option<Self::Item> {
7865        if self.is_empty && self.point.row == 0 {
7866            self.point += Point::new(1, 0);
7867            return Some(RowInfo {
7868                buffer_id: None,
7869                buffer_row: Some(0),
7870                multibuffer_row: Some(MultiBufferRow(0)),
7871                diff_status: None,
7872                expand_info: None,
7873                wrapped_buffer_row: None,
7874            });
7875        }
7876
7877        let mut region = self.cursor.region()?.clone();
7878        while self.point >= region.range.end {
7879            self.cursor.next();
7880            if let Some(next_region) = self.cursor.region() {
7881                region = next_region.clone();
7882            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7883                let multibuffer_row = MultiBufferRow(self.point.row);
7884                let last_excerpt = self
7885                    .cursor
7886                    .excerpts
7887                    .item()
7888                    .or(self.cursor.excerpts.prev_item())?;
7889                let last_row = last_excerpt
7890                    .range
7891                    .context
7892                    .end
7893                    .to_point(&last_excerpt.buffer)
7894                    .row;
7895
7896                let first_row = last_excerpt
7897                    .range
7898                    .context
7899                    .start
7900                    .to_point(&last_excerpt.buffer)
7901                    .row;
7902
7903                let expand_info = if self.is_singleton {
7904                    None
7905                } else {
7906                    let needs_expand_up = first_row == last_row
7907                        && last_row > 0
7908                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7909                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7910
7911                    if needs_expand_up && needs_expand_down {
7912                        Some(ExpandExcerptDirection::UpAndDown)
7913                    } else if needs_expand_up {
7914                        Some(ExpandExcerptDirection::Up)
7915                    } else if needs_expand_down {
7916                        Some(ExpandExcerptDirection::Down)
7917                    } else {
7918                        None
7919                    }
7920                    .map(|direction| ExpandInfo {
7921                        direction,
7922                        excerpt_id: last_excerpt.id,
7923                    })
7924                };
7925                self.point += Point::new(1, 0);
7926                return Some(RowInfo {
7927                    buffer_id: Some(last_excerpt.buffer_id),
7928                    buffer_row: Some(last_row),
7929                    multibuffer_row: Some(multibuffer_row),
7930                    diff_status: None,
7931                    wrapped_buffer_row: None,
7932                    expand_info,
7933                });
7934            } else {
7935                return None;
7936            };
7937        }
7938
7939        let overshoot = self.point - region.range.start;
7940        let buffer_point = region.buffer_range.start + overshoot;
7941        let expand_info = if self.is_singleton {
7942            None
7943        } else {
7944            let needs_expand_up = self.point.row == region.range.start.row
7945                && self.cursor.is_at_start_of_excerpt()
7946                && buffer_point.row > 0;
7947            let needs_expand_down = (region.excerpt.has_trailing_newline
7948                && self.point.row + 1 == region.range.end.row
7949                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7950                && self.cursor.is_at_end_of_excerpt()
7951                && buffer_point.row < region.buffer.max_point().row;
7952
7953            if needs_expand_up && needs_expand_down {
7954                Some(ExpandExcerptDirection::UpAndDown)
7955            } else if needs_expand_up {
7956                Some(ExpandExcerptDirection::Up)
7957            } else if needs_expand_down {
7958                Some(ExpandExcerptDirection::Down)
7959            } else {
7960                None
7961            }
7962            .map(|direction| ExpandInfo {
7963                direction,
7964                excerpt_id: region.excerpt.id,
7965            })
7966        };
7967
7968        let result = Some(RowInfo {
7969            buffer_id: Some(region.buffer.remote_id()),
7970            buffer_row: Some(buffer_point.row),
7971            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7972            diff_status: region
7973                .diff_hunk_status
7974                .filter(|_| self.point < region.range.end),
7975            expand_info,
7976            wrapped_buffer_row: None,
7977        });
7978        self.point += Point::new(1, 0);
7979        result
7980    }
7981}
7982
7983impl<'a> MultiBufferChunks<'a> {
7984    pub fn offset(&self) -> MultiBufferOffset {
7985        self.range.start
7986    }
7987
7988    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7989        self.diff_transforms.seek(&range.end, Bias::Right);
7990        let mut excerpt_end = self.diff_transforms.start().1;
7991        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7992            let overshoot = range.end - self.diff_transforms.start().0;
7993            excerpt_end += overshoot;
7994        }
7995
7996        self.diff_transforms.seek(&range.start, Bias::Right);
7997        let mut excerpt_start = self.diff_transforms.start().1;
7998        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7999            let overshoot = range.start - self.diff_transforms.start().0;
8000            excerpt_start += overshoot;
8001        }
8002
8003        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8004        self.buffer_chunk.take();
8005        self.range = range;
8006    }
8007
8008    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8009        self.excerpt_offset_range = new_range.clone();
8010        self.excerpts.seek(&new_range.start, Bias::Right);
8011        if let Some(excerpt) = self.excerpts.item() {
8012            let excerpt_start = *self.excerpts.start();
8013            if let Some(excerpt_chunks) = self
8014                .excerpt_chunks
8015                .as_mut()
8016                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8017            {
8018                excerpt.seek_chunks(
8019                    excerpt_chunks,
8020                    (self.excerpt_offset_range.start - excerpt_start)
8021                        ..(self.excerpt_offset_range.end - excerpt_start),
8022                );
8023            } else {
8024                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8025                    (self.excerpt_offset_range.start - excerpt_start)
8026                        ..(self.excerpt_offset_range.end - excerpt_start),
8027                    self.language_aware,
8028                ));
8029            }
8030        } else {
8031            self.excerpt_chunks = None;
8032        }
8033    }
8034
8035    #[ztracing::instrument(skip_all)]
8036    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8037        loop {
8038            if self.excerpt_offset_range.is_empty() {
8039                return None;
8040            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8041                self.excerpt_offset_range.start += chunk.text.len();
8042                return Some(chunk);
8043            } else {
8044                self.excerpts.next();
8045                let excerpt = self.excerpts.item()?;
8046                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8047                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8048                    self.language_aware,
8049                ));
8050            }
8051        }
8052    }
8053}
8054
8055impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8056    type Item = &'a str;
8057
8058    fn next(&mut self) -> Option<Self::Item> {
8059        let mut region = self.cursor.region()?;
8060        if self.offset == region.range.start {
8061            self.cursor.prev();
8062            region = self.cursor.region()?;
8063            let start_overshoot = self.start.saturating_sub(region.range.start);
8064            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8065                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8066            ));
8067        }
8068
8069        if self.offset == region.range.end && region.has_trailing_newline {
8070            self.offset -= 1;
8071            Some("\n")
8072        } else {
8073            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8074            self.offset -= chunk.len();
8075            Some(chunk)
8076        }
8077    }
8078}
8079
8080impl<'a> Iterator for MultiBufferChunks<'a> {
8081    type Item = Chunk<'a>;
8082
8083    #[ztracing::instrument(skip_all)]
8084    fn next(&mut self) -> Option<Chunk<'a>> {
8085        if self.range.start >= self.range.end {
8086            return None;
8087        }
8088        if self.range.start == self.diff_transforms.end().0 {
8089            self.diff_transforms.next();
8090        }
8091
8092        let diff_transform_start = self.diff_transforms.start().0;
8093        let diff_transform_end = self.diff_transforms.end().0;
8094        debug_assert!(
8095            self.range.start < diff_transform_end,
8096            "{:?} < {:?} of ({1:?}..{2:?})",
8097            self.range.start,
8098            diff_transform_end,
8099            diff_transform_start
8100        );
8101
8102        let diff_transform = self.diff_transforms.item()?;
8103        match diff_transform {
8104            DiffTransform::BufferContent { .. } => {
8105                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8106                    chunk
8107                } else {
8108                    let chunk = self.next_excerpt_chunk().unwrap();
8109                    self.buffer_chunk.insert(chunk)
8110                };
8111
8112                let chunk_end = self.range.start + chunk.text.len();
8113                let diff_transform_end = diff_transform_end.min(self.range.end);
8114
8115                if diff_transform_end < chunk_end {
8116                    let split_idx = diff_transform_end - self.range.start;
8117                    let (before, after) = chunk.text.split_at(split_idx);
8118                    self.range.start = diff_transform_end;
8119                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8120                    let chars = chunk.chars & mask;
8121                    let tabs = chunk.tabs & mask;
8122                    let newlines = chunk.newlines & mask;
8123
8124                    chunk.text = after;
8125                    chunk.chars = chunk.chars >> split_idx;
8126                    chunk.tabs = chunk.tabs >> split_idx;
8127                    chunk.newlines = chunk.newlines >> split_idx;
8128
8129                    Some(Chunk {
8130                        text: before,
8131                        chars,
8132                        tabs,
8133                        newlines,
8134                        ..chunk.clone()
8135                    })
8136                } else {
8137                    self.range.start = chunk_end;
8138                    self.buffer_chunk.take()
8139                }
8140            }
8141            DiffTransform::DeletedHunk {
8142                buffer_id,
8143                base_text_byte_range,
8144                has_trailing_newline,
8145                ..
8146            } => {
8147                let base_text_start =
8148                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8149                let base_text_end =
8150                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8151                let base_text_end = base_text_end.min(base_text_byte_range.end);
8152
8153                let mut chunks = if let Some((_, mut chunks)) = self
8154                    .diff_base_chunks
8155                    .take()
8156                    .filter(|(id, _)| id == buffer_id)
8157                {
8158                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8159                    {
8160                        chunks.seek(base_text_start..base_text_end);
8161                    }
8162                    chunks
8163                } else {
8164                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8165                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8166                };
8167
8168                let chunk = if let Some(chunk) = chunks.next() {
8169                    self.range.start += chunk.text.len();
8170                    self.diff_base_chunks = Some((*buffer_id, chunks));
8171                    chunk
8172                } else {
8173                    debug_assert!(has_trailing_newline);
8174                    self.range.start += "\n".len();
8175                    Chunk {
8176                        text: "\n",
8177                        chars: 1u128,
8178                        newlines: 1u128,
8179                        ..Default::default()
8180                    }
8181                };
8182                Some(chunk)
8183            }
8184        }
8185    }
8186}
8187
8188impl MultiBufferBytes<'_> {
8189    fn consume(&mut self, len: usize) {
8190        self.range.start += len;
8191        self.chunk = &self.chunk[len..];
8192
8193        if !self.range.is_empty() && self.chunk.is_empty() {
8194            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8195                self.chunk = chunk;
8196            } else if self.has_trailing_newline {
8197                self.has_trailing_newline = false;
8198                self.chunk = b"\n";
8199            } else {
8200                self.cursor.next();
8201                if let Some(region) = self.cursor.region() {
8202                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8203                        region.buffer_range.start
8204                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8205                                .min(region.buffer_range.end),
8206                    );
8207                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8208                    self.excerpt_bytes = Some(excerpt_bytes);
8209                    self.has_trailing_newline =
8210                        region.has_trailing_newline && self.range.end >= region.range.end;
8211                    if self.chunk.is_empty() && self.has_trailing_newline {
8212                        self.has_trailing_newline = false;
8213                        self.chunk = b"\n";
8214                    }
8215                }
8216            }
8217        }
8218    }
8219}
8220
8221impl<'a> Iterator for MultiBufferBytes<'a> {
8222    type Item = &'a [u8];
8223
8224    fn next(&mut self) -> Option<Self::Item> {
8225        let chunk = self.chunk;
8226        if chunk.is_empty() {
8227            None
8228        } else {
8229            self.consume(chunk.len());
8230            Some(chunk)
8231        }
8232    }
8233}
8234
8235impl io::Read for MultiBufferBytes<'_> {
8236    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8237        let len = cmp::min(buf.len(), self.chunk.len());
8238        buf[..len].copy_from_slice(&self.chunk[..len]);
8239        if len > 0 {
8240            self.consume(len);
8241        }
8242        Ok(len)
8243    }
8244}
8245
8246impl io::Read for ReversedMultiBufferBytes<'_> {
8247    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8248        let len = cmp::min(buf.len(), self.chunk.len());
8249        buf[..len].copy_from_slice(&self.chunk[..len]);
8250        buf[..len].reverse();
8251        if len > 0 {
8252            self.range.end -= len;
8253            self.chunk = &self.chunk[..self.chunk.len() - len];
8254            if !self.range.is_empty()
8255                && self.chunk.is_empty()
8256                && let Some(chunk) = self.chunks.next()
8257            {
8258                self.chunk = chunk.as_bytes();
8259            }
8260        }
8261        Ok(len)
8262    }
8263}
8264
8265impl<'a> Iterator for ExcerptChunks<'a> {
8266    type Item = Chunk<'a>;
8267
8268    fn next(&mut self) -> Option<Self::Item> {
8269        if let Some(chunk) = self.content_chunks.next() {
8270            return Some(chunk);
8271        }
8272
8273        if self.has_footer {
8274            let text = "\n";
8275            let chars = 0b1;
8276            let newlines = 0b1;
8277            self.has_footer = false;
8278            return Some(Chunk {
8279                text,
8280                chars,
8281                newlines,
8282                ..Default::default()
8283            });
8284        }
8285
8286        None
8287    }
8288}
8289
8290impl ToOffset for Point {
8291    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8292        snapshot.point_to_offset(*self)
8293    }
8294    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8295        snapshot.point_to_offset_utf16(*self)
8296    }
8297}
8298
8299impl ToOffset for MultiBufferOffset {
8300    #[track_caller]
8301    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8302        assert!(
8303            *self <= snapshot.len(),
8304            "offset {} is greater than the snapshot.len() {}",
8305            self.0,
8306            snapshot.len().0,
8307        );
8308        *self
8309    }
8310    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8311        snapshot.offset_to_offset_utf16(*self)
8312    }
8313}
8314
8315impl ToOffset for MultiBufferOffsetUtf16 {
8316    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8317        snapshot.offset_utf16_to_offset(*self)
8318    }
8319
8320    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8321        *self
8322    }
8323}
8324
8325impl ToOffset for PointUtf16 {
8326    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8327        snapshot.point_utf16_to_offset(*self)
8328    }
8329    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8330        snapshot.point_utf16_to_offset_utf16(*self)
8331    }
8332}
8333
8334impl ToPoint for MultiBufferOffset {
8335    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8336        snapshot.offset_to_point(*self)
8337    }
8338    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8339        snapshot.offset_to_point_utf16(*self)
8340    }
8341}
8342
8343impl ToPoint for Point {
8344    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8345        *self
8346    }
8347    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8348        snapshot.point_to_point_utf16(*self)
8349    }
8350}
8351
8352impl ToPoint for PointUtf16 {
8353    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8354        snapshot.point_utf16_to_point(*self)
8355    }
8356    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8357        *self
8358    }
8359}
8360
8361#[cfg(debug_assertions)]
8362pub mod debug {
8363    use super::*;
8364
8365    pub trait ToMultiBufferDebugRanges {
8366        fn to_multi_buffer_debug_ranges(
8367            &self,
8368            snapshot: &MultiBufferSnapshot,
8369        ) -> Vec<Range<MultiBufferOffset>>;
8370    }
8371
8372    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8373        fn to_multi_buffer_debug_ranges(
8374            &self,
8375            snapshot: &MultiBufferSnapshot,
8376        ) -> Vec<Range<MultiBufferOffset>> {
8377            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8378        }
8379    }
8380
8381    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8382        fn to_multi_buffer_debug_ranges(
8383            &self,
8384            snapshot: &MultiBufferSnapshot,
8385        ) -> Vec<Range<MultiBufferOffset>> {
8386            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8387                .to_multi_buffer_debug_ranges(snapshot)
8388        }
8389    }
8390
8391    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8392        fn to_multi_buffer_debug_ranges(
8393            &self,
8394            snapshot: &MultiBufferSnapshot,
8395        ) -> Vec<Range<MultiBufferOffset>> {
8396            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8397        }
8398    }
8399
8400    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8401        fn to_multi_buffer_debug_ranges(
8402            &self,
8403            snapshot: &MultiBufferSnapshot,
8404        ) -> Vec<Range<MultiBufferOffset>> {
8405            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8406        }
8407    }
8408
8409    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8410        fn to_multi_buffer_debug_ranges(
8411            &self,
8412            snapshot: &MultiBufferSnapshot,
8413        ) -> Vec<Range<MultiBufferOffset>> {
8414            self.iter()
8415                .map(|item| {
8416                    let offset = item.to_offset(snapshot);
8417                    offset..offset
8418                })
8419                .collect()
8420        }
8421    }
8422
8423    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8424        fn to_multi_buffer_debug_ranges(
8425            &self,
8426            snapshot: &MultiBufferSnapshot,
8427        ) -> Vec<Range<MultiBufferOffset>> {
8428            self.iter()
8429                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8430                .collect()
8431        }
8432    }
8433}