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