multi_buffer.rs

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