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