multi_buffer.rs

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