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    subscription::{Subscription, Topic},
  58};
  59use theme::SyntaxTheme;
  60use ztracing::instrument;
  61
  62pub use self::path_key::PathKey;
  63
  64pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  65
  66pub fn excerpt_context_lines(cx: &App) -> u32 {
  67    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  68}
  69
  70/// One or more [`Buffers`](Buffer) being edited in a single view.
  71///
  72/// See <https://zed.dev/features#multi-buffers>
  73pub struct MultiBuffer {
  74    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  75    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  76    snapshot: RefCell<MultiBufferSnapshot>,
  77    /// Contains the state of the buffers being edited
  78    buffers: BTreeMap<BufferId, BufferState>,
  79    /// Mapping from buffer IDs to their diff states
  80    diffs: HashMap<BufferId, DiffState>,
  81    subscriptions: Topic<MultiBufferOffset>,
  82    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  83    singleton: bool,
  84    /// The history of the multi-buffer.
  85    history: History,
  86    /// The explicit title of the multi-buffer.
  87    /// If `None`, it will be derived from the underlying path or content.
  88    title: Option<String>,
  89    /// The writing capability of the multi-buffer.
  90    capability: Capability,
  91    buffer_changed_since_sync: Rc<Cell<bool>>,
  92}
  93
  94#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
  95pub struct PathKeyIndex(u64);
  96
  97#[derive(Clone, Debug, PartialEq, Eq)]
  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<ExcerptRange<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>> {
1714        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1715        for range in expanded_ranges {
1716            if let Some(last_range) = merged_ranges.last_mut() {
1717                assert!(
1718                    last_range.context.start <= range.context.start,
1719                    "ranges must be sorted: {last_range:?} <= {range:?}"
1720                );
1721                if last_range.context.end >= range.context.start
1722                    || last_range.context.end.row + 1 == range.context.start.row
1723                {
1724                    last_range.context.end = range.context.end.max(last_range.context.end);
1725                    continue;
1726                }
1727            }
1728            merged_ranges.push(range.clone());
1729        }
1730        merged_ranges
1731    }
1732
1733    pub fn clear(&mut self, cx: &mut Context<Self>) {
1734        self.sync_mut(cx);
1735        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1736        let MultiBufferSnapshot {
1737            excerpts,
1738            diffs: _,
1739            diff_transforms: _,
1740            non_text_state_update_count: _,
1741            edit_count: _,
1742            is_dirty,
1743            has_deleted_file,
1744            has_conflict,
1745            has_inverted_diff,
1746            singleton: _,
1747            trailing_excerpt_update_count,
1748            all_diff_hunks_expanded: _,
1749            show_deleted_hunks: _,
1750            use_extended_diff_range: _,
1751            show_headers: _,
1752            path_keys_by_buffer: _,
1753            path_keys_by_index: _,
1754            buffers,
1755        } = self.snapshot.get_mut();
1756        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1757        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1758        *excerpts = Default::default();
1759        *buffers = Default::default();
1760        *trailing_excerpt_update_count += 1;
1761        *is_dirty = false;
1762        *has_deleted_file = false;
1763        *has_conflict = false;
1764        *has_inverted_diff = false;
1765
1766        let edits = Self::sync_diff_transforms(
1767            self.snapshot.get_mut(),
1768            vec![Edit {
1769                old: start..prev_len,
1770                new: start..start,
1771            }],
1772            DiffChangeKind::BufferEdited,
1773        );
1774        if !edits.is_empty() {
1775            self.subscriptions.publish(edits);
1776        }
1777        cx.emit(Event::Edited {
1778            edited_buffer: None,
1779        });
1780        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1781        cx.notify();
1782    }
1783
1784    #[ztracing::instrument(skip_all)]
1785    pub fn excerpts_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<ExcerptInfo> {
1786        let snapshot = self.read(cx);
1787        snapshot
1788            .excerpts_for_buffer(buffer_id)
1789            .map(|excerpt| excerpt.info())
1790            .collect()
1791    }
1792
1793    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1794        let snapshot = self.read(cx);
1795        let mut excerpts = snapshot
1796            .excerpts
1797            .cursor::<Dimensions<PathKey, ExcerptPoint>>(());
1798        let mut diff_transforms = snapshot
1799            .diff_transforms
1800            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1801        diff_transforms.next();
1802        let mut result = Vec::new();
1803        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id) else {
1804            return result;
1805        };
1806
1807        while let Some(excerpt) = excerpts.item()
1808            && &excerpt.path_key == path_key
1809        {
1810            let excerpt_start = excerpts.start().1;
1811            let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1812
1813            diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1814            let overshoot = excerpt_start - diff_transforms.start().0;
1815            let start = diff_transforms.start().1 + overshoot;
1816
1817            diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1818            let overshoot = excerpt_end - diff_transforms.start().0;
1819            let end = diff_transforms.start().1 + overshoot;
1820
1821            result.push(start.0..end.0);
1822            excerpts.next()
1823        }
1824        result
1825    }
1826
1827    pub fn excerpt_containing(&self, position: impl ToOffset, cx: &App) -> Option<ExcerptInfo> {
1828        let snapshot = self.read(cx);
1829        let offset = position.to_offset(&snapshot);
1830
1831        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1832        cursor.seek(&offset);
1833        let excerpt = cursor.excerpt().or(snapshot.excerpts.last())?;
1834        Some(excerpt.info())
1835    }
1836
1837    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1838        match anchor {
1839            Anchor::Min => Some(self.snapshot(cx).excerpts.first()?.buffer(self)),
1840            Anchor::Excerpt(excerpt_anchor) => self.buffer(excerpt_anchor.buffer_id),
1841            Anchor::Max => Some(self.snapshot(cx).excerpts.first()?.buffer(self)),
1842        }
1843    }
1844
1845    // If point is at the end of the buffer, the last excerpt is returned
1846    pub fn point_to_buffer_offset<T: ToOffset>(
1847        &self,
1848        point: T,
1849        cx: &App,
1850    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1851        let snapshot = self.read(cx);
1852        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1853        Some((
1854            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1855            offset,
1856        ))
1857    }
1858
1859    // If point is at the end of the buffer, the last excerpt is returned
1860    pub fn point_to_buffer_point<T: ToPoint>(
1861        &self,
1862        point: T,
1863        cx: &App,
1864    ) -> Option<(Entity<Buffer>, Point)> {
1865        let snapshot = self.read(cx);
1866        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1867        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1868    }
1869
1870    pub fn buffer_point_to_anchor(
1871        &self,
1872        // todo(lw): We shouldn't need this?
1873        buffer: &Entity<Buffer>,
1874        point: Point,
1875        cx: &App,
1876    ) -> Option<Anchor> {
1877        let mut found = None;
1878        let snapshot = buffer.read(cx).snapshot();
1879        let text_anchor = snapshot.anchor_after(&point);
1880        for excerpt in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1881            if excerpt.range.contains(&text_anchor, &snapshot) {
1882                found = Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
1883                break;
1884            }
1885            if excerpt
1886                .range
1887                .context
1888                .start
1889                .cmp(&text_anchor, &snapshot)
1890                .is_gt()
1891            {
1892                found = Some(Anchor::in_buffer(
1893                    excerpt.path_key_index,
1894                    excerpt.range.context.start,
1895                ));
1896                break;
1897            }
1898            found = Some(Anchor::in_buffer(
1899                excerpt.path_key_index,
1900                excerpt.range.context.end,
1901            ));
1902        }
1903
1904        found
1905    }
1906
1907    pub fn buffer_anchor_to_anchor(
1908        &self,
1909        // todo(lw): We shouldn't need this?
1910        buffer: &Entity<Buffer>,
1911        anchor: text::Anchor,
1912        cx: &App,
1913    ) -> Option<Anchor> {
1914        let snapshot = buffer.read(cx).snapshot();
1915        for excerpt in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1916            if excerpt.range.contains(&anchor, &snapshot) {
1917                return Some(Anchor::in_buffer(excerpt.path_key_index, anchor));
1918            }
1919        }
1920
1921        None
1922    }
1923
1924    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1925        &self,
1926        anchors: Anchors,
1927        cx: &mut Context<Self>,
1928    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1929        let mut error = None;
1930        let mut futures = Vec::new();
1931        for anchor in anchors {
1932            if let Some(excerpt_anchor) = anchor.excerpt_anchor() {
1933                if let Some(buffer) = self.buffers.get(&excerpt_anchor.buffer_id) {
1934                    buffer.buffer.update(cx, |buffer, _| {
1935                        futures.push(buffer.wait_for_anchors([excerpt_anchor.text_anchor()]))
1936                    });
1937                } else {
1938                    error = Some(anyhow!(
1939                        "buffer {:?} is not part of this multi-buffer",
1940                        excerpt_anchor.buffer_id
1941                    ));
1942                    break;
1943                }
1944            }
1945        }
1946        async move {
1947            if let Some(error) = error {
1948                Err(error)?;
1949            }
1950            for future in futures {
1951                future.await?;
1952            }
1953            Ok(())
1954        }
1955    }
1956
1957    pub fn text_anchor_for_position<T: ToOffset>(
1958        &self,
1959        position: T,
1960        cx: &App,
1961    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1962        let snapshot = self.read(cx);
1963        let anchor = snapshot.anchor_before(position).excerpt_anchor()?;
1964        let buffer = self.buffers.get(&anchor.buffer_id)?.buffer.clone();
1965        Some((buffer, anchor.text_anchor()))
1966    }
1967
1968    fn on_buffer_event(
1969        &mut self,
1970        buffer: Entity<Buffer>,
1971        event: &language::BufferEvent,
1972        cx: &mut Context<Self>,
1973    ) {
1974        use language::BufferEvent;
1975        let buffer_id = buffer.read(cx).remote_id();
1976        cx.emit(match event {
1977            BufferEvent::Edited => Event::Edited {
1978                edited_buffer: Some(buffer),
1979            },
1980            BufferEvent::DirtyChanged => Event::DirtyChanged,
1981            BufferEvent::Saved => Event::Saved,
1982            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1983            BufferEvent::Reloaded => Event::Reloaded,
1984            BufferEvent::LanguageChanged(has_language) => {
1985                Event::LanguageChanged(buffer_id, *has_language)
1986            }
1987            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1988            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1989            BufferEvent::CapabilityChanged => {
1990                self.capability = buffer.read(cx).capability();
1991                return;
1992            }
1993            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1994        });
1995    }
1996
1997    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1998        let diff = diff.read(cx);
1999        let buffer_id = diff.buffer_id;
2000        let diff = DiffStateSnapshot {
2001            diff: diff.snapshot(cx),
2002            main_buffer: None,
2003        };
2004        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2005    }
2006
2007    fn inverted_buffer_diff_language_changed(
2008        &mut self,
2009        diff: Entity<BufferDiff>,
2010        main_buffer: Entity<language::Buffer>,
2011        cx: &mut Context<Self>,
2012    ) {
2013        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2014        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2015        let diff = diff.read(cx);
2016        let diff = DiffStateSnapshot {
2017            diff: diff.snapshot(cx),
2018            main_buffer: Some(main_buffer_snapshot),
2019        };
2020        self.snapshot
2021            .get_mut()
2022            .diffs
2023            .insert(base_text_buffer_id, diff);
2024    }
2025
2026    fn buffer_diff_changed(
2027        &mut self,
2028        diff: Entity<BufferDiff>,
2029        range: Range<text::Anchor>,
2030        cx: &mut Context<Self>,
2031    ) {
2032        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2033            return;
2034        };
2035        let snapshot = self.sync_mut(cx);
2036
2037        let diff = diff.read(cx);
2038        let buffer_id = diff.buffer_id;
2039
2040        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2041            return;
2042        };
2043        let new_diff = DiffStateSnapshot {
2044            diff: diff.snapshot(cx),
2045            main_buffer: None,
2046        };
2047        let base_text_changed = snapshot
2048            .diffs
2049            .get(&buffer_id)
2050            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2051        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2052
2053        let buffer = buffer.read(cx);
2054        let diff_change_range = range.to_offset(buffer);
2055
2056        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2057        let edits = Self::sync_diff_transforms(
2058            snapshot,
2059            excerpt_edits,
2060            DiffChangeKind::DiffUpdated {
2061                base_changed: base_text_changed,
2062            },
2063        );
2064        if !edits.is_empty() {
2065            self.subscriptions.publish(edits);
2066        }
2067        cx.emit(Event::Edited {
2068            edited_buffer: None,
2069        });
2070    }
2071
2072    fn inverted_buffer_diff_changed(
2073        &mut self,
2074        diff: Entity<BufferDiff>,
2075        main_buffer: Entity<language::Buffer>,
2076        diff_change_range: Option<Range<usize>>,
2077        cx: &mut Context<Self>,
2078    ) {
2079        let snapshot = self.sync_mut(cx);
2080
2081        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2082        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2083            return;
2084        };
2085
2086        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2087        let diff = diff.read(cx);
2088        let new_diff = DiffStateSnapshot {
2089            diff: diff.snapshot(cx),
2090            main_buffer: Some(main_buffer_snapshot),
2091        };
2092        snapshot
2093            .diffs
2094            .insert_or_replace(base_text_buffer_id, new_diff);
2095
2096        let Some(diff_change_range) = diff_change_range else {
2097            return;
2098        };
2099
2100        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2101        let edits = Self::sync_diff_transforms(
2102            snapshot,
2103            excerpt_edits,
2104            DiffChangeKind::DiffUpdated {
2105                // We don't read this field for inverted diffs.
2106                base_changed: false,
2107            },
2108        );
2109        if !edits.is_empty() {
2110            self.subscriptions.publish(edits);
2111        }
2112        cx.emit(Event::Edited {
2113            edited_buffer: None,
2114        });
2115    }
2116
2117    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2118        self.buffers.values().map(|state| state.buffer.clone())
2119    }
2120
2121    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2122        self.all_buffers_iter().collect()
2123    }
2124
2125    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2126        self.buffers.keys().copied()
2127    }
2128
2129    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2130        self.all_buffer_ids_iter().collect()
2131    }
2132
2133    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2134        self.buffers
2135            .get(&buffer_id)
2136            .map(|state| state.buffer.clone())
2137    }
2138
2139    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2140        self.point_to_buffer_offset(point, cx)
2141            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2142    }
2143
2144    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2145        let snapshot = self.snapshot(cx);
2146        let buffer = snapshot
2147            .excerpts
2148            .first()
2149            .map(|excerpt| excerpt.buffer(self));
2150        buffer
2151            .map(|buffer| {
2152                let buffer = buffer.read(cx);
2153                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2154            })
2155            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2156    }
2157
2158    pub fn language_settings_at<'a, T: ToOffset>(
2159        &'a self,
2160        point: T,
2161        cx: &'a App,
2162    ) -> Cow<'a, LanguageSettings> {
2163        let mut language = None;
2164        let mut file = None;
2165        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2166            let buffer = buffer.read(cx);
2167            language = buffer.language_at(offset);
2168            file = buffer.file();
2169        }
2170        language_settings(language.map(|l| l.name()), file, cx)
2171    }
2172
2173    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2174        self.buffers.values().for_each(|state| f(&state.buffer))
2175    }
2176
2177    pub fn explicit_title(&self) -> Option<&str> {
2178        self.title.as_deref()
2179    }
2180
2181    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2182        if let Some(title) = self.title.as_ref() {
2183            return title.into();
2184        }
2185
2186        if let Some(buffer) = self.as_singleton() {
2187            let buffer = buffer.read(cx);
2188
2189            if let Some(file) = buffer.file() {
2190                return file.file_name(cx).into();
2191            }
2192
2193            if let Some(title) = self.buffer_content_title(buffer) {
2194                return title;
2195            }
2196        };
2197
2198        "untitled".into()
2199    }
2200
2201    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2202        let mut is_leading_whitespace = true;
2203        let mut count = 0;
2204        let mut prev_was_space = false;
2205        let mut title = String::new();
2206
2207        for ch in buffer.snapshot().chars() {
2208            if is_leading_whitespace && ch.is_whitespace() {
2209                continue;
2210            }
2211
2212            is_leading_whitespace = false;
2213
2214            if ch == '\n' || count >= 40 {
2215                break;
2216            }
2217
2218            if ch.is_whitespace() {
2219                if !prev_was_space {
2220                    title.push(' ');
2221                    count += 1;
2222                    prev_was_space = true;
2223                }
2224            } else {
2225                title.push(ch);
2226                count += 1;
2227                prev_was_space = false;
2228            }
2229        }
2230
2231        let title = title.trim_end().to_string();
2232
2233        if title.is_empty() {
2234            return None;
2235        }
2236
2237        Some(title.into())
2238    }
2239
2240    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2241        self.title = Some(title);
2242        cx.notify();
2243    }
2244
2245    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2246    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2247        for buffer_state in self.buffers.values() {
2248            buffer_state
2249                .buffer
2250                .update(cx, |buffer, _cx| buffer.refresh_preview());
2251        }
2252    }
2253
2254    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2255    pub fn preserve_preview(&self, cx: &App) -> bool {
2256        self.buffers
2257            .values()
2258            .all(|state| state.buffer.read(cx).preserve_preview())
2259    }
2260
2261    #[cfg(any(test, feature = "test-support"))]
2262    pub fn is_parsing(&self, cx: &App) -> bool {
2263        self.as_singleton().unwrap().read(cx).is_parsing()
2264    }
2265
2266    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2267        let buffer_id = diff.read(cx).buffer_id;
2268
2269        if let Some(existing_diff) = self.diff_for(buffer_id)
2270            && diff.entity_id() == existing_diff.entity_id()
2271        {
2272            return;
2273        }
2274
2275        self.buffer_diff_changed(
2276            diff.clone(),
2277            text::Anchor::min_max_range_for_buffer(buffer_id),
2278            cx,
2279        );
2280        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2281    }
2282
2283    pub fn add_inverted_diff(
2284        &mut self,
2285        diff: Entity<BufferDiff>,
2286        main_buffer: Entity<language::Buffer>,
2287        cx: &mut Context<Self>,
2288    ) {
2289        let snapshot = diff.read(cx).base_text(cx);
2290        let base_text_buffer_id = snapshot.remote_id();
2291        let diff_change_range = 0..snapshot.len();
2292        self.snapshot.get_mut().has_inverted_diff = true;
2293        self.inverted_buffer_diff_changed(
2294            diff.clone(),
2295            main_buffer.clone(),
2296            Some(diff_change_range),
2297            cx,
2298        );
2299        self.diffs.insert(
2300            base_text_buffer_id,
2301            DiffState::new_inverted(diff, main_buffer, cx),
2302        );
2303    }
2304
2305    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2306        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2307    }
2308
2309    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2310        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2311    }
2312
2313    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2314        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2315    }
2316
2317    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2318        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2319        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2320    }
2321
2322    pub fn all_diff_hunks_expanded(&self) -> bool {
2323        self.snapshot.borrow().all_diff_hunks_expanded
2324    }
2325
2326    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2327        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2328        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2329    }
2330
2331    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2332        self.snapshot.get_mut().show_deleted_hunks = show;
2333
2334        self.sync_mut(cx);
2335
2336        let old_len = self.snapshot.borrow().len();
2337
2338        let ranges = std::iter::once((Point::zero()..Point::MAX, Anchor::Max));
2339        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2340
2341        let new_len = self.snapshot.borrow().len();
2342
2343        self.subscriptions.publish(vec![Edit {
2344            old: MultiBufferOffset(0)..old_len,
2345            new: MultiBufferOffset(0)..new_len,
2346        }]);
2347
2348        cx.emit(Event::DiffHunksToggled);
2349        cx.emit(Event::Edited {
2350            edited_buffer: None,
2351        });
2352    }
2353
2354    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2355        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2356    }
2357
2358    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2359        self.read(cx)
2360            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2361            .nth(1)
2362            .is_some()
2363    }
2364
2365    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2366        let snapshot = self.read(cx);
2367        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2368        let offset_range = range.to_offset(&snapshot);
2369        cursor.seek(&offset_range.start, Bias::Left);
2370        while let Some(item) = cursor.item() {
2371            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2372                break;
2373            }
2374            if item.hunk_info().is_some() {
2375                return true;
2376            }
2377            cursor.next();
2378        }
2379        false
2380    }
2381
2382    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2383        let snapshot = self.read(cx);
2384        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2385        for range in ranges {
2386            let range = range.to_point(&snapshot);
2387            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2388            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2389                .min(snapshot.len());
2390            cursor.seek(&start, Bias::Right);
2391            while let Some(item) = cursor.item() {
2392                if *cursor.start() >= end {
2393                    break;
2394                }
2395                if item.hunk_info().is_some() {
2396                    return true;
2397                }
2398                cursor.next();
2399            }
2400        }
2401        false
2402    }
2403
2404    pub fn expand_or_collapse_diff_hunks_inner(
2405        &mut self,
2406        // second element is the end of the last excerpt that should be considered for this range
2407        // (or Anchor::Max to opt out)
2408        ranges: impl IntoIterator<Item = (Range<Point>, Anchor)>,
2409        expand: bool,
2410        cx: &mut Context<Self>,
2411    ) -> Vec<Edit<MultiBufferOffset>> {
2412        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2413            return Vec::new();
2414        }
2415        self.sync_mut(cx);
2416        let mut snapshot = self.snapshot.get_mut();
2417        let mut excerpt_edits = Vec::new();
2418        let mut last_hunk_row = None;
2419        for (range, excerpt_end) in ranges {
2420            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2421                if diff_hunk
2422                    .multi_buffer_range()
2423                    .end
2424                    .cmp(&excerpt_end, &snapshot)
2425                    .is_gt()
2426                {
2427                    continue;
2428                }
2429                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2430                    continue;
2431                }
2432                let range = diff_hunk.multi_buffer_range();
2433                let start = snapshot.excerpt_offset_for_anchor(&range.start);
2434                let end = snapshot.excerpt_offset_for_anchor(&range.end);
2435                last_hunk_row = Some(diff_hunk.row_range.start);
2436                excerpt_edits.push(text::Edit {
2437                    old: start..end,
2438                    new: start..end,
2439                });
2440            }
2441        }
2442
2443        Self::sync_diff_transforms(
2444            &mut snapshot,
2445            excerpt_edits,
2446            DiffChangeKind::ExpandOrCollapseHunks { expand },
2447        )
2448    }
2449
2450    pub fn expand_or_collapse_diff_hunks(
2451        &mut self,
2452        ranges: Vec<Range<Anchor>>,
2453        expand: bool,
2454        cx: &mut Context<Self>,
2455    ) {
2456        let snapshot = self.snapshot.borrow().clone();
2457        let ranges = ranges.iter().map(move |range| {
2458            let excerpt_end = snapshot
2459                .excerpt_at(range.end)
2460                .map(|excerpt| excerpt.end_anchor().into())
2461                .unwrap_or(Anchor::Max);
2462            let range = range.to_point(&snapshot);
2463            let mut peek_end = range.end;
2464            if range.end.row < snapshot.max_row().0 {
2465                peek_end = Point::new(range.end.row + 1, 0);
2466            };
2467            (range.start..peek_end, excerpt_end)
2468        });
2469        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2470        if !edits.is_empty() {
2471            self.subscriptions.publish(edits);
2472        }
2473        cx.emit(Event::DiffHunksToggled);
2474        cx.emit(Event::Edited {
2475            edited_buffer: None,
2476        });
2477    }
2478
2479    #[ztracing::instrument(skip_all)]
2480    fn sync(&self, cx: &App) {
2481        let changed = self.buffer_changed_since_sync.replace(false);
2482        if !changed {
2483            return;
2484        }
2485        let edits = Self::sync_from_buffer_changes(
2486            &mut self.snapshot.borrow_mut(),
2487            &self.buffers,
2488            &self.diffs,
2489            cx,
2490        );
2491        if !edits.is_empty() {
2492            self.subscriptions.publish(edits);
2493        }
2494    }
2495
2496    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2497        let snapshot = self.snapshot.get_mut();
2498        let changed = self.buffer_changed_since_sync.replace(false);
2499        if !changed {
2500            return snapshot;
2501        }
2502        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2503
2504        if !edits.is_empty() {
2505            self.subscriptions.publish(edits);
2506        }
2507
2508        snapshot
2509    }
2510
2511    fn sync_from_buffer_changes(
2512        snapshot: &mut MultiBufferSnapshot,
2513        buffers: &BTreeMap<BufferId, BufferState>,
2514        diffs: &HashMap<BufferId, DiffState>,
2515        cx: &App,
2516    ) -> Vec<Edit<MultiBufferOffset>> {
2517        let MultiBufferSnapshot {
2518            excerpts,
2519            diffs: buffer_diff,
2520            buffers: buffer_snapshots,
2521            path_keys_by_buffer,
2522            path_keys_by_index: _,
2523            diff_transforms: _,
2524            non_text_state_update_count,
2525            edit_count,
2526            is_dirty,
2527            has_deleted_file,
2528            has_conflict,
2529            has_inverted_diff: _,
2530            singleton: _,
2531            trailing_excerpt_update_count: _,
2532            all_diff_hunks_expanded: _,
2533            show_deleted_hunks: _,
2534            use_extended_diff_range: _,
2535            show_headers: _,
2536        } = snapshot;
2537        *is_dirty = false;
2538        *has_deleted_file = false;
2539        *has_conflict = false;
2540
2541        if !diffs.is_empty() {
2542            let mut diffs_to_add = Vec::new();
2543            for (id, diff) in diffs {
2544                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2545                // and use the diff hunk base text ranges to compute diff transforms.
2546                // Those base text ranges are usize, so make sure if the base text changed
2547                // we also update the diff snapshot so that we don't use stale offsets
2548                if buffer_diff.get(id).is_none_or(|existing_diff| {
2549                    if existing_diff.main_buffer.is_none() {
2550                        return false;
2551                    }
2552                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2553                    base_text.remote_id() != existing_diff.base_text().remote_id()
2554                        || base_text
2555                            .version()
2556                            .changed_since(existing_diff.base_text().version())
2557                }) {
2558                    if diffs_to_add.capacity() == 0 {
2559                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2560                        // meaning re-allocations will be fairly expensive
2561                        diffs_to_add.reserve(diffs.len());
2562                    }
2563                    diffs_to_add.push((*id, diff.snapshot(cx)));
2564                }
2565            }
2566            buffer_diff.extend(diffs_to_add);
2567        }
2568
2569        let mut paths_to_edit = Vec::new();
2570        let mut non_text_state_updated = false;
2571        let mut edited = false;
2572        for buffer_state in buffers.values() {
2573            let buffer = buffer_state.buffer.read(cx);
2574            let last_snapshot = buffer_snapshots
2575                .get(&buffer.remote_id())
2576                .expect("each buffer should have a snapshot");
2577            let current_version = buffer.version();
2578            let non_text_state_update_count = buffer.non_text_state_update_count();
2579
2580            let buffer_edited =
2581                current_version.changed_since(last_snapshot.buffer_snapshot.version());
2582            let buffer_non_text_state_updated = non_text_state_update_count
2583                > last_snapshot.buffer_snapshot.non_text_state_update_count();
2584            if (buffer_edited || buffer_non_text_state_updated)
2585                && let Some(path_key) = path_keys_by_buffer.get(&buffer.remote_id())
2586            {
2587                paths_to_edit.push((
2588                    path_key.clone(),
2589                    buffer_state.buffer.clone(),
2590                    if buffer_edited {
2591                        Some(last_snapshot.buffer_snapshot.version().clone())
2592                    } else {
2593                        None
2594                    },
2595                ));
2596            }
2597
2598            edited |= buffer_edited;
2599            non_text_state_updated |= buffer_non_text_state_updated;
2600            *is_dirty |= buffer.is_dirty();
2601            *has_deleted_file |= buffer
2602                .file()
2603                .is_some_and(|file| file.disk_state().is_deleted());
2604            *has_conflict |= buffer.has_conflict();
2605        }
2606        if edited {
2607            *edit_count += 1;
2608        }
2609        if non_text_state_updated {
2610            *non_text_state_update_count += 1;
2611        }
2612
2613        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path.clone());
2614
2615        let mut edits = Vec::new();
2616        let mut new_excerpts = SumTree::default();
2617        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2618
2619        for (path, buffer, prev_version) in paths_to_edit {
2620            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2621            let old_excerpt = cursor.item().unwrap();
2622            let buffer = buffer.read(cx);
2623            let buffer_id = buffer.remote_id();
2624
2625            buffer_snapshots.insert(
2626                buffer_id,
2627                BufferStateSnapshot {
2628                    path_key: path.clone(),
2629                    buffer_snapshot: buffer.snapshot(),
2630                },
2631            );
2632
2633            let new_excerpt = if let Some(prev_version) = prev_version {
2634                edits.extend(
2635                    buffer
2636                        .edits_since_in_range::<usize>(
2637                            &prev_version,
2638                            old_excerpt.range.context.clone(),
2639                        )
2640                        .map(|edit| {
2641                            let excerpt_old_start = cursor.start().len();
2642                            let excerpt_new_start =
2643                                ExcerptDimension(new_excerpts.summary().text.len);
2644                            let old_start = excerpt_old_start + edit.old.start;
2645                            let old_end = excerpt_old_start + edit.old.end;
2646                            let new_start = excerpt_new_start + edit.new.start;
2647                            let new_end = excerpt_new_start + edit.new.end;
2648                            Edit {
2649                                old: old_start..old_end,
2650                                new: new_start..new_end,
2651                            }
2652                        }),
2653                );
2654
2655                Excerpt::new(
2656                    path,
2657                    old_excerpt.path_key_index,
2658                    &buffer.snapshot(),
2659                    old_excerpt.range.clone(),
2660                    old_excerpt.has_trailing_newline,
2661                )
2662            } else {
2663                old_excerpt.clone()
2664            };
2665
2666            new_excerpts.push(new_excerpt, ());
2667            cursor.next();
2668        }
2669        new_excerpts.append(cursor.suffix(), ());
2670
2671        drop(cursor);
2672        *excerpts = new_excerpts;
2673
2674        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2675    }
2676
2677    fn sync_diff_transforms(
2678        snapshot: &mut MultiBufferSnapshot,
2679        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2680        change_kind: DiffChangeKind,
2681    ) -> Vec<Edit<MultiBufferOffset>> {
2682        if excerpt_edits.is_empty() {
2683            return vec![];
2684        }
2685
2686        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2687        let mut old_diff_transforms = snapshot
2688            .diff_transforms
2689            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2690        let mut new_diff_transforms = SumTree::default();
2691        let mut old_expanded_hunks = HashSet::default();
2692        let mut output_edits = Vec::new();
2693        let mut output_delta = 0_isize;
2694        let mut at_transform_boundary = true;
2695        let mut end_of_current_insert = None;
2696
2697        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2698        while let Some(edit) = excerpt_edits.next() {
2699            excerpts.seek_forward(&edit.new.start, Bias::Right);
2700            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2701                excerpts.prev();
2702            }
2703
2704            // Keep any transforms that are before the edit.
2705            if at_transform_boundary {
2706                at_transform_boundary = false;
2707                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2708                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2709                if let Some(transform) = old_diff_transforms.item()
2710                    && old_diff_transforms.end().0 == edit.old.start
2711                    && old_diff_transforms.start().0 < edit.old.start
2712                {
2713                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2714                    old_diff_transforms.next();
2715                }
2716            }
2717
2718            // Compute the start of the edit in output coordinates.
2719            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2720            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2721            let edit_new_start =
2722                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2723
2724            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2725                &edit,
2726                &mut excerpts,
2727                &mut old_diff_transforms,
2728                &mut new_diff_transforms,
2729                &mut end_of_current_insert,
2730                &mut old_expanded_hunks,
2731                snapshot,
2732                change_kind,
2733            );
2734
2735            // Compute the end of the edit in output coordinates.
2736            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2737            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2738            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2739            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2740            let output_edit = Edit {
2741                old: edit_old_start..edit_old_end,
2742                new: edit_new_start..edit_new_end,
2743            };
2744
2745            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2746            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2747            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2748                output_edits.push(output_edit);
2749            }
2750
2751            // If this is the last edit that intersects the current diff transform,
2752            // then recreate the content up to the end of this transform, to prepare
2753            // for reusing additional slices of the old transforms.
2754            if excerpt_edits
2755                .peek()
2756                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2757            {
2758                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2759                    && match old_diff_transforms.item() {
2760                        Some(DiffTransform::BufferContent {
2761                            inserted_hunk_info: Some(hunk),
2762                            ..
2763                        }) => excerpts.item().is_some_and(|excerpt| {
2764                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2765                                && diff.main_buffer.is_some()
2766                            {
2767                                return true;
2768                            }
2769                            hunk.hunk_start_anchor
2770                                .is_valid(&excerpt.buffer_snapshot(&snapshot))
2771                        }),
2772                        _ => true,
2773                    };
2774
2775                let mut excerpt_offset = edit.new.end;
2776                if !keep_next_old_transform {
2777                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2778                    old_diff_transforms.next();
2779                }
2780
2781                old_expanded_hunks.clear();
2782                Self::push_buffer_content_transform(
2783                    snapshot,
2784                    &mut new_diff_transforms,
2785                    excerpt_offset,
2786                    end_of_current_insert,
2787                );
2788                at_transform_boundary = true;
2789            }
2790        }
2791
2792        // Keep any transforms that are after the last edit.
2793        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2794
2795        // Ensure there's always at least one buffer content transform.
2796        if new_diff_transforms.is_empty() {
2797            new_diff_transforms.push(
2798                DiffTransform::BufferContent {
2799                    summary: Default::default(),
2800                    inserted_hunk_info: None,
2801                },
2802                (),
2803            );
2804        }
2805
2806        drop(old_diff_transforms);
2807        drop(excerpts);
2808        snapshot.diff_transforms = new_diff_transforms;
2809        snapshot.edit_count += 1;
2810
2811        #[cfg(any(test, feature = "test-support"))]
2812        snapshot.check_invariants();
2813        output_edits
2814    }
2815
2816    fn recompute_diff_transforms_for_edit(
2817        edit: &Edit<ExcerptOffset>,
2818        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2819        old_diff_transforms: &mut Cursor<
2820            DiffTransform,
2821            Dimensions<ExcerptOffset, MultiBufferOffset>,
2822        >,
2823        new_diff_transforms: &mut SumTree<DiffTransform>,
2824        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2825        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2826        snapshot: &MultiBufferSnapshot,
2827        change_kind: DiffChangeKind,
2828    ) -> bool {
2829        log::trace!(
2830            "recomputing diff transform for edit {:?} => {:?}",
2831            edit.old.start..edit.old.end,
2832            edit.new.start..edit.new.end
2833        );
2834
2835        // Record which hunks were previously expanded.
2836        while let Some(item) = old_diff_transforms.item() {
2837            if let Some(hunk_info) = item.hunk_info() {
2838                log::trace!(
2839                    "previously expanded hunk at {:?}",
2840                    old_diff_transforms.start()
2841                );
2842                old_expanded_hunks.insert(hunk_info);
2843            }
2844            if old_diff_transforms.end().0 > edit.old.end {
2845                break;
2846            }
2847            old_diff_transforms.next();
2848        }
2849
2850        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2851        // For inverted diffs, hunks are always shown, so we can't skip this.
2852        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2853        if old_expanded_hunks.is_empty()
2854            && change_kind == DiffChangeKind::BufferEdited
2855            && !all_diff_hunks_expanded
2856            && !snapshot.has_inverted_diff
2857        {
2858            return false;
2859        }
2860
2861        // Visit each excerpt that intersects the edit.
2862        let mut did_expand_hunks = false;
2863        while let Some(excerpt) = excerpts.item() {
2864            // Recompute the expanded hunks in the portion of the excerpt that
2865            // intersects the edit.
2866            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2867                let buffer_snapshot = &excerpt.buffer_snapshot(&snapshot);
2868                let excerpt_start = *excerpts.start();
2869                let excerpt_end = excerpt_start + excerpt.text_summary.len;
2870                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer_snapshot);
2871                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2872                let edit_buffer_start =
2873                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
2874                let edit_buffer_end =
2875                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
2876                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2877
2878                if let Some(main_buffer) = &diff.main_buffer {
2879                    for hunk in diff.hunks_intersecting_base_text_range(
2880                        edit_buffer_start..edit_buffer_end,
2881                        main_buffer,
2882                    ) {
2883                        did_expand_hunks = true;
2884                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
2885                        if hunk_buffer_range.start < excerpt_buffer_start {
2886                            log::trace!("skipping hunk that starts before excerpt");
2887                            continue;
2888                        }
2889                        hunk_buffer_range
2890                            .end
2891                            .to_point(&excerpt.buffer_snapshot(&snapshot));
2892                        let hunk_excerpt_start = excerpt_start
2893                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2894                        let hunk_excerpt_end = excerpt_end
2895                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2896                        Self::push_buffer_content_transform(
2897                            snapshot,
2898                            new_diff_transforms,
2899                            hunk_excerpt_start,
2900                            *end_of_current_insert,
2901                        );
2902                        if !hunk_buffer_range.is_empty() {
2903                            let hunk_info = DiffTransformHunkInfo {
2904                                buffer_id: buffer_snapshot.remote_id(),
2905                                hunk_start_anchor: hunk.buffer_range.start,
2906                                hunk_secondary_status: hunk.secondary_status,
2907                                excerpt_end: excerpt.end_anchor(),
2908                                is_logically_deleted: true,
2909                            };
2910                            *end_of_current_insert =
2911                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2912                        }
2913                    }
2914                } else {
2915                    let edit_anchor_range = buffer_snapshot.anchor_before(edit_buffer_start)
2916                        ..buffer_snapshot.anchor_after(edit_buffer_end);
2917                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer_snapshot) {
2918                        if hunk.is_created_file() && !all_diff_hunks_expanded {
2919                            continue;
2920                        }
2921
2922                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer_snapshot);
2923                        if hunk_buffer_range.start < excerpt_buffer_start {
2924                            log::trace!("skipping hunk that starts before excerpt");
2925                            continue;
2926                        }
2927
2928                        let hunk_info = DiffTransformHunkInfo {
2929                            buffer_id: buffer_snapshot.remote_id(),
2930                            hunk_start_anchor: hunk.buffer_range.start,
2931                            hunk_secondary_status: hunk.secondary_status,
2932                            excerpt_end: excerpt.end_anchor(),
2933                            is_logically_deleted: false,
2934                        };
2935
2936                        let hunk_excerpt_start = excerpt_start
2937                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2938                        let hunk_excerpt_end = excerpt_end
2939                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2940
2941                        Self::push_buffer_content_transform(
2942                            snapshot,
2943                            new_diff_transforms,
2944                            hunk_excerpt_start,
2945                            *end_of_current_insert,
2946                        );
2947
2948                        // For every existing hunk, determine if it was previously expanded
2949                        // and if it should currently be expanded.
2950                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2951                        let should_expand_hunk = match &change_kind {
2952                            DiffChangeKind::DiffUpdated { base_changed: true } => {
2953                                was_previously_expanded || all_diff_hunks_expanded
2954                            }
2955                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2956                                let intersects = hunk_buffer_range.is_empty()
2957                                    || hunk_buffer_range.end > edit_buffer_start;
2958                                if *expand {
2959                                    intersects || was_previously_expanded || all_diff_hunks_expanded
2960                                } else {
2961                                    !intersects
2962                                        && (was_previously_expanded || all_diff_hunks_expanded)
2963                                }
2964                            }
2965                            _ => was_previously_expanded || all_diff_hunks_expanded,
2966                        };
2967
2968                        if should_expand_hunk {
2969                            did_expand_hunks = true;
2970                            log::trace!(
2971                                "expanding hunk {:?}",
2972                                hunk_excerpt_start..hunk_excerpt_end,
2973                            );
2974
2975                            if !hunk.diff_base_byte_range.is_empty()
2976                                && hunk_buffer_range.start >= edit_buffer_start
2977                                && hunk_buffer_range.start <= excerpt_buffer_end
2978                                && snapshot.show_deleted_hunks
2979                            {
2980                                let base_text = diff.base_text();
2981                                let mut text_cursor =
2982                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2983                                let mut base_text_summary = text_cursor
2984                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
2985
2986                                let mut has_trailing_newline = false;
2987                                if base_text_summary.last_line_chars > 0 {
2988                                    base_text_summary += TextSummary::newline();
2989                                    has_trailing_newline = true;
2990                                }
2991
2992                                new_diff_transforms.push(
2993                                    DiffTransform::DeletedHunk {
2994                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
2995                                        summary: base_text_summary,
2996                                        buffer_id: buffer_snapshot.remote_id(),
2997                                        hunk_info,
2998                                        has_trailing_newline,
2999                                    },
3000                                    (),
3001                                );
3002                            }
3003
3004                            if !hunk_buffer_range.is_empty() {
3005                                *end_of_current_insert =
3006                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3007                            }
3008                        }
3009                    }
3010                }
3011            }
3012
3013            if excerpts.end() <= edit.new.end {
3014                excerpts.next();
3015            } else {
3016                break;
3017            }
3018        }
3019
3020        did_expand_hunks || !old_expanded_hunks.is_empty()
3021    }
3022
3023    fn append_diff_transforms(
3024        new_transforms: &mut SumTree<DiffTransform>,
3025        subtree: SumTree<DiffTransform>,
3026    ) {
3027        if let Some(DiffTransform::BufferContent {
3028            inserted_hunk_info,
3029            summary,
3030        }) = subtree.first()
3031            && Self::extend_last_buffer_content_transform(
3032                new_transforms,
3033                *inserted_hunk_info,
3034                *summary,
3035            )
3036        {
3037            let mut cursor = subtree.cursor::<()>(());
3038            cursor.next();
3039            cursor.next();
3040            new_transforms.append(cursor.suffix(), ());
3041            return;
3042        }
3043        new_transforms.append(subtree, ());
3044    }
3045
3046    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3047        if let DiffTransform::BufferContent {
3048            inserted_hunk_info: inserted_hunk_anchor,
3049            summary,
3050        } = transform
3051            && Self::extend_last_buffer_content_transform(
3052                new_transforms,
3053                inserted_hunk_anchor,
3054                summary,
3055            )
3056        {
3057            return;
3058        }
3059        new_transforms.push(transform, ());
3060    }
3061
3062    fn push_buffer_content_transform(
3063        old_snapshot: &MultiBufferSnapshot,
3064        new_transforms: &mut SumTree<DiffTransform>,
3065        end_offset: ExcerptOffset,
3066        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3067    ) {
3068        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3069            (end_offset.min(insertion_end_offset), Some(hunk_info))
3070        });
3071        let unchanged_region = [(end_offset, None)];
3072
3073        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3074        {
3075            let start_offset = new_transforms.summary().excerpt_len();
3076            if end_offset <= start_offset {
3077                continue;
3078            }
3079            let summary_to_add = old_snapshot
3080                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3081
3082            if !Self::extend_last_buffer_content_transform(
3083                new_transforms,
3084                inserted_hunk_info,
3085                summary_to_add,
3086            ) {
3087                new_transforms.push(
3088                    DiffTransform::BufferContent {
3089                        summary: summary_to_add,
3090                        inserted_hunk_info,
3091                    },
3092                    (),
3093                )
3094            }
3095        }
3096    }
3097
3098    fn extend_last_buffer_content_transform(
3099        new_transforms: &mut SumTree<DiffTransform>,
3100        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3101        summary_to_add: MBTextSummary,
3102    ) -> bool {
3103        let mut did_extend = false;
3104        new_transforms.update_last(
3105            |last_transform| {
3106                if let DiffTransform::BufferContent {
3107                    summary,
3108                    inserted_hunk_info: inserted_hunk_anchor,
3109                } = last_transform
3110                    && *inserted_hunk_anchor == new_inserted_hunk_info
3111                {
3112                    *summary += summary_to_add;
3113                    did_extend = true;
3114                }
3115            },
3116            (),
3117        );
3118        did_extend
3119    }
3120
3121    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3122        let snapshot = self.snapshot(cx);
3123        let excerpt_end = snapshot
3124            .excerpt_at(range.end)
3125            .map(|excerpt| excerpt.end_anchor().into())
3126            .unwrap_or(Anchor::Max);
3127        let point_range = range.to_point(&snapshot);
3128        let expand = !self.single_hunk_is_expanded(range, cx);
3129        let edits =
3130            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_end)], expand, cx);
3131        if !edits.is_empty() {
3132            self.subscriptions.publish(edits);
3133        }
3134        cx.emit(Event::DiffHunksToggled);
3135        cx.emit(Event::Edited {
3136            edited_buffer: None,
3137        });
3138    }
3139}
3140
3141fn build_excerpt_ranges(
3142    ranges: impl IntoIterator<Item = Range<Point>>,
3143    context_line_count: u32,
3144    buffer_snapshot: &BufferSnapshot,
3145) -> Vec<ExcerptRange<Point>> {
3146    ranges
3147        .into_iter()
3148        .map(|range| {
3149            let start_row = range.start.row.saturating_sub(context_line_count);
3150            let start = Point::new(start_row, 0);
3151            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3152            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3153            ExcerptRange {
3154                context: start..end,
3155                primary: range,
3156            }
3157        })
3158        .collect()
3159}
3160
3161#[cfg(any(test, feature = "test-support"))]
3162impl MultiBuffer {
3163    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3164        let buffer = cx.new(|cx| Buffer::local(text, cx));
3165        cx.new(|cx| Self::singleton(buffer, cx))
3166    }
3167
3168    pub fn build_multi<const COUNT: usize>(
3169        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3170        cx: &mut gpui::App,
3171    ) -> Entity<Self> {
3172        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3173        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3174            let buffer = cx.new(|cx| Buffer::local(text, cx));
3175            let snapshot = buffer.read(cx).snapshot();
3176            let excerpt_ranges = ranges
3177                .into_iter()
3178                .map(ExcerptRange::new)
3179                .collect::<Vec<_>>();
3180            multi.update(cx, |multi, cx| {
3181                multi.set_excerpt_ranges_for_path(
3182                    PathKey::sorted(ix as u64),
3183                    buffer,
3184                    &snapshot,
3185                    excerpt_ranges,
3186                    cx,
3187                )
3188            });
3189        }
3190
3191        multi
3192    }
3193
3194    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3195        cx.new(|cx| Self::singleton(buffer, cx))
3196    }
3197
3198    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3199        cx.new(|cx| {
3200            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3201            let mutation_count = rng.random_range(1..=5);
3202            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3203            multibuffer
3204        })
3205    }
3206
3207    pub fn randomly_edit(
3208        &mut self,
3209        rng: &mut impl rand::Rng,
3210        edit_count: usize,
3211        cx: &mut Context<Self>,
3212    ) {
3213        use util::RandomCharIter;
3214
3215        let snapshot = self.read(cx);
3216        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3217        let mut last_end = None;
3218        for _ in 0..edit_count {
3219            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3220                break;
3221            }
3222
3223            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3224            let end =
3225                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3226            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3227            last_end = Some(end);
3228
3229            let mut range = start..end;
3230            if rng.random_bool(0.2) {
3231                mem::swap(&mut range.start, &mut range.end);
3232            }
3233
3234            let new_text_len = rng.random_range(0..10);
3235            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3236
3237            edits.push((range, new_text.into()));
3238        }
3239        log::info!("mutating multi-buffer with {:?}", edits);
3240        drop(snapshot);
3241
3242        self.edit(edits, None, cx);
3243    }
3244
3245    pub fn randomly_edit_excerpts(
3246        &mut self,
3247        rng: &mut impl rand::Rng,
3248        mutation_count: usize,
3249        cx: &mut Context<Self>,
3250    ) {
3251        use rand::prelude::*;
3252        use std::env;
3253        use util::RandomCharIter;
3254
3255        let max_buffers = env::var("MAX_BUFFERS")
3256            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3257            .unwrap_or(5);
3258
3259        let mut buffers = Vec::new();
3260        for _ in 0..mutation_count {
3261            let buffer_ids = self.all_buffer_ids();
3262            if buffer_ids.is_empty() || (rng.random() && buffer_ids.len() < max_buffers) {
3263                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3264                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3265                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3266                    let buffer = buffers.last().unwrap().read(cx);
3267                    log::info!(
3268                        "Creating new buffer {} with text: {:?}",
3269                        buffer.remote_id(),
3270                        buffer.text()
3271                    );
3272                    buffers.last().unwrap().clone()
3273                } else {
3274                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3275                };
3276
3277                let buffer = buffer_handle.read(cx);
3278                let buffer_text = buffer.text();
3279                let buffer_snapshot = buffer.snapshot();
3280                let mut next_min_start_ix = 0;
3281                let ranges = (0..rng.random_range(0..5))
3282                    .filter_map(|_| {
3283                        if next_min_start_ix == buffer.len() {
3284                            return None;
3285                        }
3286                        let end_ix = buffer.clip_offset(
3287                            rng.random_range(next_min_start_ix..=buffer.len()),
3288                            Bias::Right,
3289                        );
3290                        let start_ix = buffer
3291                            .clip_offset(rng.random_range(next_min_start_ix..=end_ix), Bias::Left);
3292                        next_min_start_ix = end_ix;
3293                        Some(ExcerptRange::new(start_ix..end_ix))
3294                    })
3295                    .collect::<Vec<_>>();
3296                log::info!(
3297                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3298                    buffer_handle.read(cx).remote_id(),
3299                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3300                    ranges
3301                        .iter()
3302                        .map(|r| &buffer_text[r.context.clone()])
3303                        .collect::<Vec<_>>()
3304                );
3305
3306                let path_key = PathKey::sorted(rng.random_range(0..max_buffers * 3) as u64);
3307                self.set_merged_excerpt_ranges_for_path(
3308                    path_key.clone(),
3309                    buffer_handle,
3310                    &buffer_snapshot,
3311                    ranges,
3312                    cx,
3313                );
3314                log::info!("Inserted with path_key: {:?}", path_key);
3315            } else {
3316                let path_key = self
3317                    .snapshot
3318                    .borrow()
3319                    .path_keys_by_buffer
3320                    .get(&buffer_ids.choose(rng).unwrap())
3321                    .cloned()
3322                    .unwrap();
3323                log::info!("Removing excerpts {:?}", path_key);
3324                self.remove_excerpts_for_path(path_key, cx);
3325            }
3326        }
3327    }
3328
3329    pub fn randomly_mutate(
3330        &mut self,
3331        rng: &mut impl rand::Rng,
3332        mutation_count: usize,
3333        cx: &mut Context<Self>,
3334    ) {
3335        use rand::prelude::*;
3336
3337        if rng.random_bool(0.7) || self.singleton {
3338            let buffer = self
3339                .buffers
3340                .values()
3341                .choose(rng)
3342                .map(|state| state.buffer.clone());
3343
3344            if let Some(buffer) = buffer {
3345                buffer.update(cx, |buffer, cx| {
3346                    if rng.random() {
3347                        buffer.randomly_edit(rng, mutation_count, cx);
3348                    } else {
3349                        buffer.randomly_undo_redo(rng, cx);
3350                    }
3351                });
3352            } else {
3353                self.randomly_edit(rng, mutation_count, cx);
3354            }
3355        } else {
3356            self.randomly_edit_excerpts(rng, mutation_count, cx);
3357        }
3358
3359        self.check_invariants(cx);
3360    }
3361
3362    fn check_invariants(&self, cx: &App) {
3363        self.read(cx).check_invariants();
3364    }
3365}
3366
3367impl EventEmitter<Event> for MultiBuffer {}
3368
3369impl MultiBufferSnapshot {
3370    pub fn text(&self) -> String {
3371        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3372            .map(|chunk| chunk.text)
3373            .collect()
3374    }
3375
3376    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3377        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3378            .flat_map(|c| c.chars().rev())
3379    }
3380
3381    fn reversed_chunks_in_range(
3382        &self,
3383        range: Range<MultiBufferOffset>,
3384    ) -> ReversedMultiBufferChunks<'_> {
3385        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3386        cursor.seek(&range.end);
3387        let current_chunks = cursor.region().as_ref().map(|region| {
3388            let start_overshoot = range.start.saturating_sub(region.range.start);
3389            let end_overshoot = range.end - region.range.start;
3390            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3391            let start = region.buffer_range.start + start_overshoot;
3392            region.buffer.reversed_chunks_in_range(start..end)
3393        });
3394        ReversedMultiBufferChunks {
3395            cursor,
3396            current_chunks,
3397            start: range.start,
3398            offset: range.end,
3399        }
3400    }
3401
3402    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3403        let offset = position.to_offset(self);
3404        self.text_for_range(offset..self.len())
3405            .flat_map(|chunk| chunk.chars())
3406    }
3407
3408    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3409        self.chunks(range, false).map(|chunk| chunk.text)
3410    }
3411
3412    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3413        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3414            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3415    }
3416
3417    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3418    where
3419        T: ToOffset,
3420    {
3421        let position = position.to_offset(self);
3422        position == self.clip_offset(position, Bias::Left)
3423            && self
3424                .bytes_in_range(position..self.len())
3425                .flatten()
3426                .copied()
3427                .take(needle.len())
3428                .eq(needle.bytes())
3429    }
3430
3431    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3432        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3433    }
3434
3435    pub fn diff_hunks_in_range<T: ToPoint>(
3436        &self,
3437        range: Range<T>,
3438    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3439        let query_range = range.start.to_point(self)..range.end.to_point(self);
3440        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3441            let diff = self.diffs.get(&buffer.remote_id())?;
3442            let iter = if let Some(main_buffer) = &diff.main_buffer {
3443                let buffer_start = buffer.point_to_offset(buffer_range.start);
3444                let buffer_end = buffer.point_to_offset(buffer_range.end);
3445                itertools::Either::Left(
3446                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3447                        .map(move |hunk| (hunk, buffer, true)),
3448                )
3449            } else {
3450                let buffer_start = buffer.anchor_before(buffer_range.start);
3451                let buffer_end = buffer.anchor_after(buffer_range.end);
3452                itertools::Either::Right(
3453                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3454                        .map(move |hunk| (hunk, buffer, false)),
3455                )
3456            };
3457            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3458                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3459                    return None;
3460                }
3461                let range = if is_inverted {
3462                    hunk.diff_base_byte_range.to_point(&buffer)
3463                } else {
3464                    hunk.range.clone()
3465                };
3466                Some((range, (hunk, is_inverted)))
3467            }))
3468        })
3469        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3470            let buffer_snapshot = excerpt.buffer_snapshot(self);
3471            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3472            {
3473                return None;
3474            }
3475            let end_row = if range.end.column == 0 {
3476                range.end.row
3477            } else {
3478                range.end.row + 1
3479            };
3480
3481            let word_diffs =
3482                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3483                    .then(|| {
3484                        let mut word_diffs = Vec::new();
3485
3486                        if self.show_deleted_hunks || is_inverted {
3487                            let hunk_start_offset = if is_inverted {
3488                                Anchor::in_buffer(
3489                                    excerpt.path_key_index,
3490                                    buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start),
3491                                )
3492                                .to_offset(self)
3493                            } else {
3494                                Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3495                                    .to_offset(self)
3496                            };
3497
3498                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3499                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3500                            }));
3501                        }
3502
3503                        if !is_inverted {
3504                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3505                                Anchor::range_in_buffer(excerpt.path_key_index, diff)
3506                                    .to_offset(self)
3507                            }));
3508                        }
3509                        word_diffs
3510                    })
3511                    .unwrap_or_default();
3512
3513            let buffer_range = if is_inverted {
3514                buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start)
3515                    ..buffer_snapshot.anchor_before(hunk.diff_base_byte_range.end)
3516            } else {
3517                hunk.buffer_range.clone()
3518            };
3519            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3520                DiffHunkStatusKind::Deleted
3521            } else if hunk.diff_base_byte_range.is_empty() {
3522                DiffHunkStatusKind::Added
3523            } else {
3524                DiffHunkStatusKind::Modified
3525            };
3526            Some(MultiBufferDiffHunk {
3527                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3528                buffer_id: buffer_snapshot.remote_id(),
3529                path_key_index: excerpt.path_key_index,
3530                buffer_range,
3531                word_diffs,
3532                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3533                    ..BufferOffset(hunk.diff_base_byte_range.end),
3534                status: DiffHunkStatus {
3535                    kind: status_kind,
3536                    secondary: hunk.secondary_status,
3537                },
3538            })
3539        })
3540    }
3541
3542    fn excerpts_for_range<T: ToOffset>(
3543        &self,
3544        range: Range<T>,
3545    ) -> impl Iterator<Item = &Excerpt> + '_ {
3546        let range = range.start.to_offset(self)..range.end.to_offset(self);
3547        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3548        cursor.seek(&range.start);
3549        std::iter::from_fn(move || {
3550            let region = cursor.region()?;
3551            if region.range.start > range.end
3552                || region.range.start == range.end && region.range.start > range.start
3553            {
3554                return None;
3555            }
3556            let excerpt = region.excerpt;
3557            cursor.next_excerpt_forwards();
3558            Some(excerpt)
3559        })
3560    }
3561
3562    // todo!() repeats ids? seems weird
3563    pub fn buffer_ids_for_range<T: ToOffset>(
3564        &self,
3565        range: Range<T>,
3566    ) -> impl Iterator<Item = BufferId> + '_ {
3567        self.excerpts_for_range(range)
3568            .map(|excerpt| excerpt.buffer_snapshot(self).remote_id())
3569    }
3570
3571    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3572    ///
3573    /// The passed in anchors must be ordered.
3574    pub fn text_anchors_to_visible_anchors(
3575        &self,
3576        anchors: impl IntoIterator<Item = text::Anchor>,
3577    ) -> Vec<Option<Anchor>> {
3578        let anchors = anchors.into_iter();
3579        let mut result = Vec::with_capacity(anchors.size_hint().0);
3580        let mut anchors = anchors.peekable();
3581        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3582        'anchors: while let Some(anchor) = anchors.peek() {
3583            let Some(buffer_id) = anchor.buffer_id else {
3584                anchors.next();
3585                result.push(None);
3586                continue 'anchors;
3587            };
3588            let mut same_buffer_anchors =
3589                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3590
3591            if let Some(path) = self.path_keys_by_buffer.get(&buffer_id) {
3592                let Some(mut next) = same_buffer_anchors.next() else {
3593                    continue 'anchors;
3594                };
3595                cursor.seek_forward(path, Bias::Left);
3596                'excerpts: loop {
3597                    let Some(excerpt) = cursor.item() else {
3598                        break;
3599                    };
3600                    if &excerpt.path_key != path {
3601                        break;
3602                    }
3603                    let buffer_snapshot = excerpt.buffer_snapshot(self);
3604
3605                    loop {
3606                        // anchor is before the first excerpt
3607                        if excerpt
3608                            .range
3609                            .context
3610                            .start
3611                            .cmp(&next, &buffer_snapshot)
3612                            .is_gt()
3613                        {
3614                            // so we skip it and try the next anchor
3615                            result.push(None);
3616                            match same_buffer_anchors.next() {
3617                                Some(anchor) => next = anchor,
3618                                None => continue 'anchors,
3619                            }
3620                        // anchor is within the excerpt
3621                        } else if excerpt
3622                            .range
3623                            .context
3624                            .end
3625                            .cmp(&next, &buffer_snapshot)
3626                            .is_ge()
3627                        {
3628                            // record it and all following anchors that are within
3629                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3630                            result.extend(
3631                                same_buffer_anchors
3632                                    .peeking_take_while(|a| {
3633                                        excerpt.range.context.end.cmp(a, &buffer_snapshot).is_ge()
3634                                    })
3635                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3636                            );
3637                            match same_buffer_anchors.next() {
3638                                Some(anchor) => next = anchor,
3639                                None => continue 'anchors,
3640                            }
3641                        // anchor is after the excerpt, try the next one
3642                        } else {
3643                            cursor.next();
3644                            continue 'excerpts;
3645                        }
3646                    }
3647                }
3648                // account for `next`
3649                result.push(None);
3650            }
3651            result.extend(same_buffer_anchors.map(|_| None));
3652        }
3653
3654        result
3655    }
3656
3657    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3658        &self,
3659        ranges: impl Iterator<Item = Range<T>>,
3660    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>)> {
3661        ranges.flat_map(|range| {
3662            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3663                .into_iter()
3664        })
3665    }
3666
3667    pub fn range_to_buffer_ranges<R, T>(
3668        &self,
3669        range: R,
3670    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>)>
3671    where
3672        R: RangeBounds<T>,
3673        T: ToOffset,
3674    {
3675        self.range_to_buffer_ranges_with_context(range)
3676            .into_iter()
3677            .map(|(buffer, range, _context)| (buffer, range))
3678            .collect()
3679    }
3680
3681    pub fn range_to_buffer_ranges_with_context<R, T>(
3682        &self,
3683        range: R,
3684    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)>
3685    where
3686        R: RangeBounds<T>,
3687        T: ToOffset,
3688    {
3689        let start = match range.start_bound() {
3690            Bound::Included(start) => start.to_offset(self),
3691            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3692            Bound::Unbounded => MultiBufferOffset::ZERO,
3693        };
3694        let end_bound = match range.end_bound() {
3695            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3696            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3697            Bound::Unbounded => Bound::Unbounded,
3698        };
3699        let bounds = (Bound::Included(start), end_bound);
3700
3701        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3702        cursor.seek(&start);
3703
3704        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)> =
3705            Vec::new();
3706        let mut last_excerpt = None;
3707        while let Some(region) = cursor.region() {
3708            let dominated_by_end_bound = match end_bound {
3709                Bound::Included(end) => region.range.start > end,
3710                Bound::Excluded(end) => region.range.start >= end,
3711                Bound::Unbounded => false,
3712            };
3713            if dominated_by_end_bound {
3714                break;
3715            }
3716            if region.is_main_buffer {
3717                let start_overshoot = start.saturating_sub(region.range.start);
3718                let end_offset = match end_bound {
3719                    Bound::Included(end) | Bound::Excluded(end) => end,
3720                    Bound::Unbounded => region.range.end,
3721                };
3722                let end_overshoot = end_offset.saturating_sub(region.range.start);
3723                let start = region
3724                    .buffer_range
3725                    .end
3726                    .min(region.buffer_range.start + start_overshoot);
3727                let end = region
3728                    .buffer_range
3729                    .end
3730                    .min(region.buffer_range.start + end_overshoot);
3731                let context = region.excerpt.range.context.clone();
3732                if last_excerpt
3733                    .as_ref()
3734                    .is_some_and(|prev_excerpt| prev_excerpt == &region.excerpt.info())
3735                    && let Some(prev) = result
3736                        .last_mut()
3737                        .filter(|(_, prev_range, _)| prev_range.end == start)
3738                {
3739                    prev.1.end = end;
3740                } else {
3741                    result.push((region.buffer, start..end, context));
3742                    // todo!() is there a better way to do this?
3743                    last_excerpt = Some(region.excerpt.info())
3744                }
3745            }
3746            cursor.next();
3747        }
3748
3749        if let Some(excerpt) = cursor.excerpt() {
3750            let dominated_by_prev_excerpt =
3751                last_excerpt.is_some_and(|last_excerpt| last_excerpt == excerpt.info());
3752            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3753                let excerpt_position = self.len();
3754                let buffer_snapshot = excerpt.buffer_snapshot(self);
3755                if bounds.contains(&excerpt_position) {
3756                    let buffer_offset =
3757                        BufferOffset(excerpt.range.context.start.to_offset(buffer_snapshot));
3758                    let context = excerpt.range.context.clone();
3759                    result.push((buffer_snapshot, buffer_offset..buffer_offset, context));
3760                }
3761            }
3762        }
3763
3764        result
3765    }
3766
3767    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3768        &self,
3769        range: Range<T>,
3770    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, Option<Anchor>)> + '_ {
3771        let start = range.start.to_offset(self);
3772        let end = range.end.to_offset(self);
3773
3774        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3775        cursor.seek(&start);
3776
3777        std::iter::from_fn(move || {
3778            let region = cursor.region()?;
3779            if region.range.start > end {
3780                return None;
3781            }
3782            let start_overshoot = start.saturating_sub(region.range.start);
3783            let end_overshoot = end.saturating_sub(region.range.start);
3784            let start = region
3785                .buffer_range
3786                .end
3787                .min(region.buffer_range.start + start_overshoot);
3788            let end = region
3789                .buffer_range
3790                .end
3791                .min(region.buffer_range.start + end_overshoot);
3792
3793            let deleted_hunk_anchor = if region.is_main_buffer {
3794                None
3795            } else {
3796                Some(self.anchor_before(region.range.start))
3797            };
3798            let result = (region.buffer, start..end, deleted_hunk_anchor);
3799            cursor.next();
3800            Some(result)
3801        })
3802    }
3803
3804    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3805    /// coordinates.
3806    ///
3807    /// The given callback will be called for every excerpt intersecting the given range. It will
3808    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3809    /// The callback should return an iterator of metadata items from that buffer, each paired
3810    /// with a buffer range.
3811    ///
3812    /// The returned iterator yields each of these metadata items, paired with its range in
3813    /// multi-buffer coordinates.
3814    fn lift_buffer_metadata<'a, MBD, M, I>(
3815        &'a self,
3816        query_range: Range<MBD>,
3817        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3818    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3819    where
3820        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3821        MBD: MultiBufferDimension
3822            + Ord
3823            + Sub<Output = MBD::TextDimension>
3824            + ops::Add<MBD::TextDimension, Output = MBD>
3825            + ops::AddAssign<MBD::TextDimension>,
3826        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3827            + ops::Add<Output = MBD::TextDimension>
3828            + AddAssign<MBD::TextDimension>
3829            + Ord,
3830    {
3831        let mut current_excerpt_metadata: Option<(ExcerptAnchor, I)> = None;
3832        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3833
3834        // Find the excerpt and buffer offset where the given range ends.
3835        cursor.seek(&query_range.end);
3836        let mut range_end = None;
3837        while let Some(region) = cursor.region() {
3838            if region.is_main_buffer {
3839                let mut buffer_end = region.buffer_range.start;
3840                let overshoot = if query_range.end > region.range.start {
3841                    query_range.end - region.range.start
3842                } else {
3843                    <MBD::TextDimension>::default()
3844                };
3845                buffer_end = buffer_end + overshoot;
3846                range_end = Some((region.excerpt.end_anchor(), buffer_end));
3847                break;
3848            }
3849            cursor.next();
3850        }
3851
3852        cursor.seek(&query_range.start);
3853
3854        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3855            && region.range.start > MBD::default()
3856        {
3857            cursor.prev()
3858        } else if let Some(region) = cursor.region()
3859            && region.is_main_buffer
3860            && region.diff_hunk_status.is_some()
3861        {
3862            cursor.prev();
3863            if cursor.region().is_none_or(|region| region.is_main_buffer) {
3864                cursor.next();
3865            }
3866        }
3867
3868        iter::from_fn(move || {
3869            loop {
3870                let excerpt = cursor.excerpt()?;
3871                let buffer_snapshot = excerpt.buffer_snapshot(self);
3872
3873                // If we have already retrieved metadata for this excerpt, continue to use it.
3874                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3875                    .as_mut()
3876                    .filter(|(excerpt_anchor, _)| excerpt_anchor == &excerpt.end_anchor())
3877                {
3878                    Some(metadata)
3879                }
3880                // Otherwise, compute the intersection of the input range with the excerpt's range,
3881                // and retrieve the metadata for the resulting range.
3882                else {
3883                    let region = cursor.region()?;
3884                    let mut buffer_start;
3885                    if region.is_main_buffer {
3886                        buffer_start = region.buffer_range.start;
3887                        if query_range.start > region.range.start {
3888                            let overshoot = query_range.start - region.range.start;
3889                            buffer_start = buffer_start + overshoot;
3890                        }
3891                        buffer_start = buffer_start.min(region.buffer_range.end);
3892                    } else {
3893                        buffer_start = cursor.main_buffer_position()?;
3894                    };
3895                    let mut buffer_end = excerpt
3896                        .range
3897                        .context
3898                        .end
3899                        .summary::<MBD::TextDimension>(&buffer_snapshot);
3900                    if let Some((end_excerpt, end_buffer_offset)) = range_end
3901                        && excerpt.end_anchor() == end_excerpt
3902                    {
3903                        buffer_end = buffer_end.min(end_buffer_offset);
3904                    }
3905
3906                    get_buffer_metadata(&buffer_snapshot, buffer_start..buffer_end).map(
3907                        |iterator| {
3908                            &mut current_excerpt_metadata
3909                                .insert((excerpt.end_anchor(), iterator))
3910                                .1
3911                        },
3912                    )
3913                };
3914
3915                // Visit each metadata item.
3916                if let Some((metadata_buffer_range, metadata)) =
3917                    metadata_iter.and_then(Iterator::next)
3918                {
3919                    // Find the multibuffer regions that contain the start and end of
3920                    // the metadata item's range.
3921                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3922                        while let Some(region) = cursor.region() {
3923                            if (region.is_main_buffer
3924                                && (region.buffer_range.end >= metadata_buffer_range.start
3925                                    || cursor.is_at_end_of_excerpt()))
3926                                || (!region.is_main_buffer
3927                                    && region.buffer_range.start == metadata_buffer_range.start)
3928                            {
3929                                break;
3930                            }
3931                            cursor.next();
3932                        }
3933                    }
3934                    let start_region = cursor.region()?.clone();
3935                    while let Some(region) = cursor.region() {
3936                        if region.is_main_buffer
3937                            && (region.buffer_range.end > metadata_buffer_range.end
3938                                || cursor.is_at_end_of_excerpt())
3939                        {
3940                            break;
3941                        }
3942                        cursor.next();
3943                    }
3944                    let end_region = cursor.region();
3945
3946                    // Convert the metadata item's range into multibuffer coordinates.
3947                    let mut start_position = start_region.range.start;
3948                    let region_buffer_start = start_region.buffer_range.start;
3949                    if start_region.is_main_buffer
3950                        && metadata_buffer_range.start > region_buffer_start
3951                    {
3952                        start_position =
3953                            start_position + (metadata_buffer_range.start - region_buffer_start);
3954                        start_position = start_position.min(start_region.range.end);
3955                    }
3956
3957                    let mut end_position = self.max_position();
3958                    if let Some(end_region) = &end_region {
3959                        end_position = end_region.range.start;
3960                        debug_assert!(end_region.is_main_buffer);
3961                        let region_buffer_start = end_region.buffer_range.start;
3962                        if metadata_buffer_range.end > region_buffer_start {
3963                            end_position =
3964                                end_position + (metadata_buffer_range.end - region_buffer_start);
3965                        }
3966                        end_position = end_position.min(end_region.range.end);
3967                    }
3968
3969                    if start_position <= query_range.end && end_position >= query_range.start {
3970                        return Some((start_position..end_position, metadata, excerpt));
3971                    }
3972                }
3973                // When there are no more metadata items for this excerpt, move to the next excerpt.
3974                else {
3975                    current_excerpt_metadata.take();
3976                    if let Some((end_excerpt, _)) = range_end
3977                        && excerpt.end_anchor() == end_excerpt
3978                    {
3979                        return None;
3980                    }
3981                    cursor.next_excerpt_forwards();
3982                }
3983            }
3984        })
3985    }
3986
3987    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3988        let offset = position.to_offset(self);
3989
3990        let mut cursor = self
3991            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
3992            );
3993        cursor.seek(&DimensionPair {
3994            key: offset,
3995            value: None,
3996        });
3997        cursor.seek_to_start_of_current_excerpt();
3998        let excerpt = cursor.excerpt()?;
3999
4000        let buffer = excerpt.buffer_snapshot(self);
4001        let excerpt_start = excerpt.range.context.start.to_offset(buffer);
4002        let excerpt_end = excerpt.range.context.end.to_offset(buffer);
4003        let current_position = match self.anchor_before(offset) {
4004            Anchor::Min => 0,
4005            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor.text_anchor().to_offset(buffer),
4006            Anchor::Max => unreachable!(),
4007        };
4008
4009        if let Some(diff) = self.diffs.get(&buffer.remote_id()) {
4010            if let Some(main_buffer) = &diff.main_buffer {
4011                for hunk in diff
4012                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4013                {
4014                    if hunk.diff_base_byte_range.end >= current_position {
4015                        continue;
4016                    }
4017                    let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
4018                    let start =
4019                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4020                    return Some(MultiBufferRow(start.row));
4021                }
4022            } else {
4023                let excerpt_end = buffer.anchor_before(excerpt_end.min(current_position));
4024                for hunk in diff
4025                    .hunks_intersecting_range_rev(excerpt.range.context.start..excerpt_end, buffer)
4026                {
4027                    let hunk_end = hunk.buffer_range.end.to_offset(buffer);
4028                    if hunk_end >= current_position {
4029                        continue;
4030                    }
4031                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4032                        .to_point(self);
4033                    return Some(MultiBufferRow(start.row));
4034                }
4035            }
4036        }
4037
4038        loop {
4039            cursor.prev_excerpt();
4040            let excerpt = cursor.excerpt()?;
4041
4042            let buffer = excerpt.buffer_snapshot(self);
4043            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
4044                continue;
4045            };
4046            if let Some(main_buffer) = &diff.main_buffer {
4047                let Some(hunk) = diff
4048                    .hunks_intersecting_base_text_range_rev(
4049                        excerpt.range.context.to_offset(buffer),
4050                        main_buffer,
4051                    )
4052                    .next()
4053                else {
4054                    continue;
4055                };
4056                let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
4057                let start = Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4058                return Some(MultiBufferRow(start.row));
4059            } else {
4060                let Some(hunk) = diff
4061                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), buffer)
4062                    .next()
4063                else {
4064                    continue;
4065                };
4066                let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4067                    .to_point(self);
4068                return Some(MultiBufferRow(start.row));
4069            }
4070        }
4071    }
4072
4073    pub fn has_diff_hunks(&self) -> bool {
4074        self.diffs.values().any(|diff| !diff.is_empty())
4075    }
4076
4077    pub fn is_inside_word<T: ToOffset>(
4078        &self,
4079        position: T,
4080        scope_context: Option<CharScopeContext>,
4081    ) -> bool {
4082        let position = position.to_offset(self);
4083        let classifier = self
4084            .char_classifier_at(position)
4085            .scope_context(scope_context);
4086        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4087        let prev_char_kind = self
4088            .reversed_chars_at(position)
4089            .next()
4090            .map(|c| classifier.kind(c));
4091        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4092    }
4093
4094    pub fn surrounding_word<T: ToOffset>(
4095        &self,
4096        start: T,
4097        scope_context: Option<CharScopeContext>,
4098    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4099        let mut start = start.to_offset(self);
4100        let mut end = start;
4101        let mut next_chars = self.chars_at(start).peekable();
4102        let mut prev_chars = self.reversed_chars_at(start).peekable();
4103
4104        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4105
4106        let word_kind = cmp::max(
4107            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4108            next_chars.peek().copied().map(|c| classifier.kind(c)),
4109        );
4110
4111        for ch in prev_chars {
4112            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4113                start -= ch.len_utf8();
4114            } else {
4115                break;
4116            }
4117        }
4118
4119        for ch in next_chars {
4120            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4121                end += ch.len_utf8();
4122            } else {
4123                break;
4124            }
4125        }
4126
4127        (start..end, word_kind)
4128    }
4129
4130    pub fn char_kind_before<T: ToOffset>(
4131        &self,
4132        start: T,
4133        scope_context: Option<CharScopeContext>,
4134    ) -> Option<CharKind> {
4135        let start = start.to_offset(self);
4136        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4137        self.reversed_chars_at(start)
4138            .next()
4139            .map(|ch| classifier.kind(ch))
4140    }
4141
4142    pub fn is_singleton(&self) -> bool {
4143        self.singleton
4144    }
4145
4146    pub fn as_singleton(&self) -> Option<&BufferSnapshot> {
4147        if self.singleton {
4148            self.excerpts.first().map(|e| e.buffer_snapshot(self))
4149        } else {
4150            None
4151        }
4152    }
4153
4154    pub fn len(&self) -> MultiBufferOffset {
4155        self.diff_transforms.summary().output.len
4156    }
4157
4158    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4159        MBD::from_summary(&self.text_summary())
4160    }
4161
4162    pub fn is_empty(&self) -> bool {
4163        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4164    }
4165
4166    pub fn widest_line_number(&self) -> u32 {
4167        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4168        self.excerpts.summary().widest_line_number + 1
4169    }
4170
4171    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4172        let range = range.start.to_offset(self)..range.end.to_offset(self);
4173        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4174        excerpts.seek(&range.start);
4175
4176        let mut chunk;
4177        let mut has_trailing_newline;
4178        let excerpt_bytes;
4179        if let Some(region) = excerpts.region() {
4180            let mut bytes = region.buffer.bytes_in_range(
4181                region.buffer_range.start + (range.start - region.range.start)
4182                    ..(region.buffer_range.start + (range.end - region.range.start))
4183                        .min(region.buffer_range.end),
4184            );
4185            chunk = bytes.next().unwrap_or(&[][..]);
4186            excerpt_bytes = Some(bytes);
4187            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4188            if chunk.is_empty() && has_trailing_newline {
4189                chunk = b"\n";
4190                has_trailing_newline = false;
4191            }
4192        } else {
4193            chunk = &[][..];
4194            excerpt_bytes = None;
4195            has_trailing_newline = false;
4196        };
4197
4198        MultiBufferBytes {
4199            range,
4200            cursor: excerpts,
4201            excerpt_bytes,
4202            has_trailing_newline,
4203            chunk,
4204        }
4205    }
4206
4207    pub fn reversed_bytes_in_range<T: ToOffset>(
4208        &self,
4209        range: Range<T>,
4210    ) -> ReversedMultiBufferBytes<'_> {
4211        let range = range.start.to_offset(self)..range.end.to_offset(self);
4212        let mut chunks = self.reversed_chunks_in_range(range.clone());
4213        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4214        ReversedMultiBufferBytes {
4215            range,
4216            chunks,
4217            chunk,
4218        }
4219    }
4220
4221    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4222        let mut cursor = self.cursor::<Point, Point>();
4223        cursor.seek(&Point::new(start_row.0, 0));
4224        let mut result = MultiBufferRows {
4225            point: Point::new(0, 0),
4226            is_empty: self.excerpts.is_empty(),
4227            is_singleton: self.is_singleton(),
4228            cursor,
4229        };
4230        result.seek(start_row);
4231        result
4232    }
4233
4234    pub fn chunks<T: ToOffset>(
4235        &self,
4236        range: Range<T>,
4237        language_aware: bool,
4238    ) -> MultiBufferChunks<'_> {
4239        let mut chunks = MultiBufferChunks {
4240            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4241                ..ExcerptDimension(MultiBufferOffset::ZERO),
4242            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4243            excerpts: self.excerpts.cursor(()),
4244            diff_transforms: self.diff_transforms.cursor(()),
4245            diff_base_chunks: None,
4246            excerpt_chunks: None,
4247            buffer_chunk: None,
4248            language_aware,
4249            snapshot: self,
4250        };
4251        let range = range.start.to_offset(self)..range.end.to_offset(self);
4252        chunks.seek(range);
4253        chunks
4254    }
4255
4256    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4257        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4258    }
4259
4260    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4261        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4262    }
4263
4264    pub fn clip_offset_utf16(
4265        &self,
4266        offset: MultiBufferOffsetUtf16,
4267        bias: Bias,
4268    ) -> MultiBufferOffsetUtf16 {
4269        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4270    }
4271
4272    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4273        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4274            buffer.clip_point_utf16(Unclipped(point), bias)
4275        })
4276    }
4277
4278    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4279        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4280    }
4281
4282    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4283        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4284    }
4285
4286    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4287        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4288    }
4289
4290    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4291        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4292    }
4293
4294    #[instrument(skip_all)]
4295    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4296        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4297    }
4298
4299    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4300        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4301    }
4302
4303    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4304        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4305    }
4306
4307    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4308        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4309    }
4310
4311    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4312        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4313    }
4314
4315    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4316        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4317    }
4318
4319    fn clip_dimension<MBD, BD>(
4320        &self,
4321        position: MBD,
4322        bias: Bias,
4323        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4324    ) -> MBD
4325    where
4326        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4327        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4328    {
4329        let mut cursor = self.cursor::<MBD, BD>();
4330        cursor.seek(&position);
4331        if let Some(region) = cursor.region() {
4332            if position >= region.range.end {
4333                return region.range.end;
4334            }
4335            let overshoot = position - region.range.start;
4336            let mut buffer_position = region.buffer_range.start;
4337            buffer_position += overshoot;
4338            let clipped_buffer_position =
4339                clip_buffer_position(region.buffer, buffer_position, bias);
4340            let mut position = region.range.start;
4341            position += clipped_buffer_position - region.buffer_range.start;
4342            position
4343        } else {
4344            self.max_position()
4345        }
4346    }
4347
4348    #[instrument(skip_all)]
4349    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4350        &self,
4351        key: MBR1,
4352        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4353    ) -> MBR2
4354    where
4355        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4356        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4357        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4358        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4359    {
4360        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4361        cursor.seek(&DimensionPair { key, value: None });
4362        if let Some(region) = cursor.region() {
4363            if key >= region.range.end.key {
4364                return region.range.end.value.unwrap();
4365            }
4366            let start_key = region.range.start.key;
4367            let start_value = region.range.start.value.unwrap();
4368            let buffer_start_key = region.buffer_range.start.key;
4369            let buffer_start_value = region.buffer_range.start.value.unwrap();
4370            let mut buffer_key = buffer_start_key;
4371            buffer_key += key - start_key;
4372            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4373            let mut result = start_value;
4374            result += buffer_value - buffer_start_value;
4375            result
4376        } else {
4377            self.max_position()
4378        }
4379    }
4380
4381    pub fn point_to_buffer_offset<T: ToOffset>(
4382        &self,
4383        point: T,
4384    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4385        let offset = point.to_offset(self);
4386        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4387        cursor.seek(&offset);
4388        let region = cursor.region()?;
4389        let overshoot = offset - region.range.start;
4390        let buffer_offset = region.buffer_range.start + overshoot;
4391        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4392            && region.has_trailing_newline
4393            && !region.is_main_buffer
4394        {
4395            let main_buffer_position = cursor.main_buffer_position()?;
4396            let buffer_snapshot = cursor.excerpt()?.buffer_snapshot(self);
4397            return Some((buffer_snapshot, main_buffer_position));
4398        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4399            return None;
4400        }
4401        Some((region.buffer, buffer_offset))
4402    }
4403
4404    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4405        let mut cursor = self.cursor::<Point, Point>();
4406        cursor.seek(&point);
4407        let region = cursor.region()?;
4408        let overshoot = point - region.range.start;
4409        let buffer_point = region.buffer_range.start + overshoot;
4410        let excerpt = cursor.excerpt()?;
4411        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4412            && region.has_trailing_newline
4413            && !region.is_main_buffer
4414        {
4415            return Some((
4416                &excerpt.buffer_snapshot(self),
4417                cursor.main_buffer_position()?,
4418            ));
4419        } else if buffer_point > region.buffer.max_point() {
4420            return None;
4421        }
4422        Some((region.buffer, buffer_point))
4423    }
4424
4425    pub fn suggested_indents(
4426        &self,
4427        rows: impl IntoIterator<Item = u32>,
4428        cx: &App,
4429    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4430        let mut result = BTreeMap::new();
4431        self.suggested_indents_callback(
4432            rows,
4433            &mut |row, indent| {
4434                result.insert(row, indent);
4435                ControlFlow::Continue(())
4436            },
4437            cx,
4438        );
4439        result
4440    }
4441
4442    // move this to be a generator once those are a thing
4443    pub fn suggested_indents_callback(
4444        &self,
4445        rows: impl IntoIterator<Item = u32>,
4446        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4447        cx: &App,
4448    ) {
4449        let mut rows_for_excerpt = Vec::new();
4450        let mut cursor = self.cursor::<Point, Point>();
4451        let mut rows = rows.into_iter().peekable();
4452        let mut prev_row = u32::MAX;
4453        let mut prev_language_indent_size = IndentSize::default();
4454
4455        while let Some(row) = rows.next() {
4456            cursor.seek(&Point::new(row, 0));
4457            let Some(region) = cursor.region() else {
4458                continue;
4459            };
4460
4461            // Retrieve the language and indent size once for each disjoint region being indented.
4462            let single_indent_size = if row.saturating_sub(1) == prev_row {
4463                prev_language_indent_size
4464            } else {
4465                region
4466                    .buffer
4467                    .language_indent_size_at(Point::new(row, 0), cx)
4468            };
4469            prev_language_indent_size = single_indent_size;
4470            prev_row = row;
4471
4472            let start_buffer_row = region.buffer_range.start.row;
4473            let start_multibuffer_row = region.range.start.row;
4474            let end_multibuffer_row = region.range.end.row;
4475
4476            rows_for_excerpt.push(row);
4477            while let Some(next_row) = rows.peek().copied() {
4478                if end_multibuffer_row > next_row {
4479                    rows_for_excerpt.push(next_row);
4480                    rows.next();
4481                } else {
4482                    break;
4483                }
4484            }
4485
4486            let buffer_rows = rows_for_excerpt
4487                .drain(..)
4488                .map(|row| start_buffer_row + row - start_multibuffer_row);
4489            let buffer_indents = region
4490                .buffer
4491                .suggested_indents(buffer_rows, single_indent_size);
4492            for (row, indent) in buffer_indents {
4493                if cb(
4494                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4495                    indent,
4496                )
4497                .is_break()
4498                {
4499                    return;
4500                }
4501            }
4502        }
4503    }
4504
4505    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4506        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4507            let mut size = buffer.indent_size_for_line(range.start.row);
4508            size.len = size
4509                .len
4510                .min(range.end.column)
4511                .saturating_sub(range.start.column);
4512            size
4513        } else {
4514            IndentSize::spaces(0)
4515        }
4516    }
4517
4518    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4519        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4520            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4521        } else {
4522            LineIndent::spaces(0)
4523        }
4524    }
4525
4526    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4527        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4528
4529        if self.language_settings(cx).extend_comment_on_newline
4530            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4531        {
4532            let delimiters = language_scope.line_comment_prefixes();
4533            for delimiter in delimiters {
4534                if *self
4535                    .chars_at(Point::new(row.0, indent.len() as u32))
4536                    .take(delimiter.chars().count())
4537                    .collect::<String>()
4538                    .as_str()
4539                    == **delimiter
4540                {
4541                    indent.push_str(delimiter);
4542                    break;
4543                }
4544            }
4545        }
4546
4547        indent
4548    }
4549
4550    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4551    where
4552        T: ToOffset,
4553    {
4554        for char in self.reversed_chars_at(position) {
4555            if !char.is_whitespace() {
4556                return false;
4557            }
4558            if char == '\n' {
4559                return true;
4560            }
4561        }
4562        true
4563    }
4564
4565    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4566        while row.0 > 0 {
4567            row.0 -= 1;
4568            if !self.is_line_blank(row) {
4569                return Some(row);
4570            }
4571        }
4572        None
4573    }
4574
4575    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4576        if let Some((_, range)) = self.buffer_line_for_row(row) {
4577            range.end.column - range.start.column
4578        } else {
4579            0
4580        }
4581    }
4582
4583    pub fn buffer_line_for_row(
4584        &self,
4585        row: MultiBufferRow,
4586    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4587        let mut cursor = self.cursor::<Point, Point>();
4588        let point = Point::new(row.0, 0);
4589        cursor.seek(&point);
4590        let region = cursor.region()?;
4591        let overshoot = point.min(region.range.end) - region.range.start;
4592        let buffer_point = region.buffer_range.start + overshoot;
4593        if buffer_point.row > region.buffer_range.end.row {
4594            return None;
4595        }
4596        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4597        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4598            .min(region.buffer_range.end);
4599        Some((region.buffer, line_start..line_end))
4600    }
4601
4602    pub fn max_point(&self) -> Point {
4603        self.text_summary().lines
4604    }
4605
4606    pub fn max_row(&self) -> MultiBufferRow {
4607        MultiBufferRow(self.text_summary().lines.row)
4608    }
4609
4610    pub fn text_summary(&self) -> MBTextSummary {
4611        self.diff_transforms.summary().output
4612    }
4613
4614    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4615    where
4616        MBD: MultiBufferDimension + AddAssign,
4617        O: ToOffset,
4618    {
4619        let range = range.start.to_offset(self)..range.end.to_offset(self);
4620        let mut cursor = self
4621            .diff_transforms
4622            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4623        cursor.seek(&range.start, Bias::Right);
4624
4625        let Some(first_transform) = cursor.item() else {
4626            return MBD::from_summary(&MBTextSummary::default());
4627        };
4628
4629        let diff_transform_start = cursor.start().0;
4630        let diff_transform_end = cursor.end().0;
4631        let diff_start = range.start;
4632        let start_overshoot = diff_start - diff_transform_start;
4633        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4634
4635        let mut result = match first_transform {
4636            DiffTransform::BufferContent { .. } => {
4637                let excerpt_start = cursor.start().1 + start_overshoot;
4638                let excerpt_end = cursor.start().1 + end_overshoot;
4639                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4640            }
4641            DiffTransform::DeletedHunk {
4642                buffer_id,
4643                base_text_byte_range,
4644                has_trailing_newline,
4645                ..
4646            } => {
4647                let buffer_start = base_text_byte_range.start + start_overshoot;
4648                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4649                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4650                    panic!("{:?} is in non-existent deleted hunk", range.start)
4651                };
4652
4653                let include_trailing_newline =
4654                    *has_trailing_newline && range.end >= diff_transform_end;
4655                if include_trailing_newline {
4656                    buffer_end -= 1;
4657                }
4658
4659                let mut summary = base_text
4660                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4661
4662                if include_trailing_newline {
4663                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4664                        &TextSummary::newline(),
4665                    ))
4666                }
4667
4668                let mut result = MBD::default();
4669                result.add_text_dim(&summary);
4670                result
4671            }
4672        };
4673        if range.end < diff_transform_end {
4674            return result;
4675        }
4676
4677        cursor.next();
4678        result.add_mb_text_summary(
4679            &cursor
4680                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4681                .0,
4682        );
4683
4684        let Some(last_transform) = cursor.item() else {
4685            return result;
4686        };
4687
4688        let overshoot = range.end - cursor.start().0;
4689        let suffix = match last_transform {
4690            DiffTransform::BufferContent { .. } => {
4691                let end = cursor.start().1 + overshoot;
4692                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4693            }
4694            DiffTransform::DeletedHunk {
4695                base_text_byte_range,
4696                buffer_id,
4697                has_trailing_newline,
4698                ..
4699            } => {
4700                let buffer_end = base_text_byte_range.start + overshoot;
4701                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4702                    panic!("{:?} is in non-existent deleted hunk", range.end)
4703                };
4704
4705                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4706                    base_text_byte_range.start..buffer_end,
4707                );
4708                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4709                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4710                        &TextSummary::from("\n"),
4711                    ))
4712                }
4713
4714                let mut result = MBD::default();
4715                result.add_text_dim(&suffix);
4716                result
4717            }
4718        };
4719
4720        result += suffix;
4721        result
4722    }
4723
4724    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4725    where
4726        MBD: MultiBufferDimension + AddAssign,
4727    {
4728        let mut summary = MBD::default();
4729        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4730        cursor.seek(&range.start, Bias::Right);
4731        if let Some(excerpt) = cursor.item() {
4732            let buffer_snapshot = excerpt.buffer_snapshot(self);
4733            let mut end_before_newline = cursor.end();
4734            if excerpt.has_trailing_newline {
4735                end_before_newline -= 1;
4736            }
4737
4738            let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4739            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4740            let end_in_excerpt =
4741                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4742            summary.add_text_dim(
4743                &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4744                    start_in_excerpt..end_in_excerpt,
4745                ),
4746            );
4747
4748            if range.end > end_before_newline {
4749                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4750            }
4751
4752            cursor.next();
4753        }
4754
4755        if range.end > *cursor.start() {
4756            summary += cursor
4757                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4758                .0;
4759            if let Some(excerpt) = cursor.item() {
4760                let buffer_snapshot = excerpt.buffer_snapshot(self);
4761                range.end = cmp::max(*cursor.start(), range.end);
4762
4763                let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4764                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4765                summary.add_text_dim(
4766                    &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4767                        excerpt_start..end_in_excerpt,
4768                    ),
4769                );
4770            }
4771        }
4772
4773        summary
4774    }
4775
4776    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4777    where
4778        MBD: MultiBufferDimension
4779            + Ord
4780            + Sub<Output = MBD::TextDimension>
4781            + Sub<MBD::TextDimension, Output = MBD>
4782            + AddAssign<MBD::TextDimension>
4783            + Add<MBD::TextDimension, Output = MBD>,
4784        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4785    {
4786        let target = anchor.seek_target(self);
4787        let anchor = match anchor {
4788            Anchor::Min => {
4789                return MBD::default();
4790            }
4791            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4792            Anchor::Max => {
4793                return MBD::from_summary(&self.text_summary());
4794            }
4795        };
4796
4797        let (start, _, item) = self
4798            .excerpts
4799            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4800        let start = MBD::from_summary(&start.text);
4801
4802        let excerpt_start_position = ExcerptDimension(start);
4803        if self.diff_transforms.is_empty() {
4804            if let Some(excerpt) = item {
4805                if !excerpt.contains(anchor, self) {
4806                    return excerpt_start_position.0;
4807                }
4808                let buffer_snapshot = excerpt.buffer_snapshot(self);
4809                let excerpt_buffer_start = excerpt
4810                    .range
4811                    .context
4812                    .start
4813                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4814                let excerpt_buffer_end = excerpt
4815                    .range
4816                    .context
4817                    .end
4818                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4819                let buffer_summary = anchor
4820                    .text_anchor()
4821                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4822                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4823                let mut position = excerpt_start_position;
4824                if summary > excerpt_buffer_start {
4825                    position += summary - excerpt_buffer_start;
4826                }
4827
4828                position.0
4829            } else {
4830                excerpt_start_position.0
4831            }
4832        } else {
4833            let mut diff_transforms_cursor = self
4834                .diff_transforms
4835                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4836            diff_transforms_cursor.next();
4837
4838            if let Some(excerpt) = item {
4839                if !excerpt.contains(anchor, self) {
4840                    return self.summary_for_excerpt_position_without_hunks(
4841                        Bias::Left,
4842                        excerpt_start_position,
4843                        &mut diff_transforms_cursor,
4844                    );
4845                }
4846                let buffer_snapshot = excerpt.buffer_snapshot(self);
4847                let excerpt_buffer_start = excerpt
4848                    .range
4849                    .context
4850                    .start
4851                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4852                let excerpt_buffer_end = excerpt
4853                    .range
4854                    .context
4855                    .end
4856                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4857                let buffer_summary = anchor
4858                    .text_anchor()
4859                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4860                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4861                let mut position = excerpt_start_position;
4862                if summary > excerpt_buffer_start {
4863                    position += summary - excerpt_buffer_start;
4864                }
4865
4866                if diff_transforms_cursor.start().0 < position {
4867                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
4868                }
4869                self.summary_for_anchor_with_excerpt_position(
4870                    *anchor,
4871                    position,
4872                    &mut diff_transforms_cursor,
4873                    &buffer_snapshot,
4874                )
4875            } else {
4876                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
4877                self.summary_for_excerpt_position_without_hunks(
4878                    Bias::Right,
4879                    excerpt_start_position,
4880                    &mut diff_transforms_cursor,
4881                )
4882            }
4883        }
4884    }
4885
4886    /// Maps an anchor's excerpt-space position to its output-space position by
4887    /// walking the diff transforms. The cursor is shared across consecutive
4888    /// calls, so it may already be partway through the transform list.
4889    fn summary_for_anchor_with_excerpt_position<MBD>(
4890        &self,
4891        anchor: ExcerptAnchor,
4892        excerpt_position: ExcerptDimension<MBD>,
4893        diff_transforms: &mut Cursor<
4894            DiffTransform,
4895            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4896        >,
4897        excerpt_buffer: &text::BufferSnapshot,
4898    ) -> MBD
4899    where
4900        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4901    {
4902        loop {
4903            let transform_end_position = diff_transforms.end().0;
4904            let item = diff_transforms.item();
4905            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4906
4907            // A right-biased anchor at a transform boundary belongs to the
4908            // *next* transform, so advance past the current one.
4909            if anchor.bias == Bias::Right && at_transform_end {
4910                diff_transforms.next();
4911                continue;
4912            }
4913
4914            let mut position = diff_transforms.start().1;
4915            match item {
4916                Some(DiffTransform::DeletedHunk {
4917                    buffer_id,
4918                    base_text_byte_range,
4919                    hunk_info,
4920                    ..
4921                }) => {
4922                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
4923                        && let Some(base_text) =
4924                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4925                        && diff_base_anchor.is_valid(&base_text)
4926                    {
4927                        // The anchor carries a diff-base position — resolve it
4928                        // to a location inside the deleted hunk.
4929                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4930                        if base_text_offset >= base_text_byte_range.start
4931                            && base_text_offset <= base_text_byte_range.end
4932                        {
4933                            let position_in_hunk = base_text
4934                                .text_summary_for_range::<MBD::TextDimension, _>(
4935                                    base_text_byte_range.start..base_text_offset,
4936                                );
4937                            position.0.add_text_dim(&position_in_hunk);
4938                        } else if at_transform_end {
4939                            // diff_base offset falls outside this hunk's range;
4940                            // advance to see if the next transform is a better fit.
4941                            diff_transforms.next();
4942                            continue;
4943                        }
4944                    } else if at_transform_end
4945                        && anchor
4946                            .text_anchor()
4947                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
4948                            .is_gt()
4949                    {
4950                        // The anchor has no (valid) diff-base position, so it
4951                        // belongs in the buffer content, not in the deleted
4952                        // hunk. However, after an edit deletes the text between
4953                        // the hunk boundary and this anchor, both resolve to
4954                        // the same excerpt_position—landing us here on the
4955                        // DeletedHunk left behind by the shared cursor. Use the
4956                        // CRDT ordering to detect that the anchor is strictly
4957                        // *past* the hunk boundary and skip to the following
4958                        // BufferContent.
4959                        diff_transforms.next();
4960                        continue;
4961                    }
4962                }
4963                _ => {
4964                    // On a BufferContent (or no transform). If the anchor
4965                    // carries a diff_base_anchor it needs a DeletedHunk, so
4966                    // advance to find one.
4967                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4968                        diff_transforms.next();
4969                        continue;
4970                    }
4971                    let overshoot = excerpt_position - diff_transforms.start().0;
4972                    position += overshoot;
4973                }
4974            }
4975
4976            return position.0;
4977        }
4978    }
4979
4980    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
4981    fn summary_for_excerpt_position_without_hunks<MBD>(
4982        &self,
4983        bias: Bias,
4984        excerpt_position: ExcerptDimension<MBD>,
4985        diff_transforms: &mut Cursor<
4986            DiffTransform,
4987            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4988        >,
4989    ) -> MBD
4990    where
4991        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4992    {
4993        loop {
4994            let transform_end_position = diff_transforms.end().0;
4995            let item = diff_transforms.item();
4996            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4997
4998            // A right-biased anchor at a transform boundary belongs to the
4999            // *next* transform, so advance past the current one.
5000            if bias == Bias::Right && at_transform_end {
5001                diff_transforms.next();
5002                continue;
5003            }
5004
5005            let mut position = diff_transforms.start().1;
5006            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5007                let overshoot = excerpt_position - diff_transforms.start().0;
5008                position += overshoot;
5009            }
5010
5011            return position.0;
5012        }
5013    }
5014
5015    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5016        let anchor = match anchor {
5017            Anchor::Min => return ExcerptOffset::default(),
5018            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5019            Anchor::Max => return self.excerpts.summary().len(),
5020        };
5021        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5022        let target = anchor.seek_target(self);
5023
5024        cursor.seek(&target, Bias::Left);
5025
5026        let mut position = cursor.start().len();
5027        if let Some(excerpt) = cursor.item()
5028            && excerpt.contains(anchor, self)
5029        {
5030            let buffer_snapshot = excerpt.buffer_snapshot(self);
5031            let excerpt_buffer_start =
5032                buffer_snapshot.offset_for_anchor(&excerpt.range.context.start);
5033            let excerpt_buffer_end = buffer_snapshot.offset_for_anchor(&excerpt.range.context.end);
5034            let buffer_position = cmp::min(
5035                excerpt_buffer_end,
5036                buffer_snapshot.offset_for_anchor(&anchor.text_anchor()),
5037            );
5038            if buffer_position > excerpt_buffer_start {
5039                position += buffer_position - excerpt_buffer_start;
5040            }
5041        }
5042        position
5043    }
5044
5045    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5046    where
5047        MBD: MultiBufferDimension
5048            + Ord
5049            + Sub<Output = MBD::TextDimension>
5050            + AddAssign<MBD::TextDimension>,
5051        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5052        I: 'a + IntoIterator<Item = &'a Anchor>,
5053    {
5054        let mut anchors = anchors.into_iter().peekable();
5055        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5056        let mut diff_transforms_cursor = self
5057            .diff_transforms
5058            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5059        diff_transforms_cursor.next();
5060
5061        let mut summaries = Vec::new();
5062        while let Some(anchor) = anchors.peek() {
5063            let target = anchor.seek_target(self);
5064            let excerpt_anchor = match anchor {
5065                Anchor::Min => {
5066                    summaries.push(MBD::default());
5067                    anchors.next();
5068                    continue;
5069                }
5070                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5071                Anchor::Max => {
5072                    summaries.push(MBD::from_summary(&self.text_summary()));
5073                    anchors.next();
5074                    continue;
5075                }
5076            };
5077
5078            cursor.seek_forward(&target, Bias::Left);
5079
5080            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5081            if let Some(excerpt) = cursor.item() {
5082                let buffer_snapshot = excerpt.buffer_snapshot(self);
5083                if !excerpt.contains(&excerpt_anchor, self) {
5084                    let position = self.summary_for_excerpt_position_without_hunks(
5085                        Bias::Left,
5086                        excerpt_start_position,
5087                        &mut diff_transforms_cursor,
5088                    );
5089                    summaries.push(position);
5090                    anchors.next();
5091                    continue;
5092                }
5093                let excerpt_buffer_start = excerpt
5094                    .range
5095                    .context
5096                    .start
5097                    .summary::<MBD::TextDimension>(buffer_snapshot);
5098                let excerpt_buffer_end = excerpt
5099                    .range
5100                    .context
5101                    .end
5102                    .summary::<MBD::TextDimension>(buffer_snapshot);
5103                for (buffer_summary, excerpt_anchor) in buffer_snapshot
5104                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5105                        std::iter::from_fn(|| {
5106                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5107                            if !excerpt.contains(&excerpt_anchor, self) {
5108                                return None;
5109                            }
5110                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5111                        }),
5112                    )
5113                {
5114                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5115                    let mut position = excerpt_start_position;
5116                    if summary > excerpt_buffer_start {
5117                        position += summary - excerpt_buffer_start;
5118                    }
5119
5120                    if diff_transforms_cursor.start().0 < position {
5121                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5122                    }
5123
5124                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5125                        excerpt_anchor,
5126                        position,
5127                        &mut diff_transforms_cursor,
5128                        &buffer_snapshot,
5129                    ));
5130                }
5131            } else {
5132                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5133                let position = self.summary_for_excerpt_position_without_hunks(
5134                    Bias::Right,
5135                    excerpt_start_position,
5136                    &mut diff_transforms_cursor,
5137                );
5138                summaries.push(position);
5139                anchors.next();
5140            }
5141        }
5142
5143        summaries
5144    }
5145
5146    pub fn dimensions_from_points<'a, MBD>(
5147        &'a self,
5148        points: impl 'a + IntoIterator<Item = Point>,
5149    ) -> impl 'a + Iterator<Item = MBD>
5150    where
5151        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5152    {
5153        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5154        cursor.seek(&DimensionPair {
5155            key: Point::default(),
5156            value: None,
5157        });
5158        let mut points = points.into_iter();
5159        iter::from_fn(move || {
5160            let point = points.next()?;
5161
5162            cursor.seek_forward(&DimensionPair {
5163                key: point,
5164                value: None,
5165            });
5166
5167            if let Some(region) = cursor.region() {
5168                let overshoot = point - region.range.start.key;
5169                let buffer_point = region.buffer_range.start + overshoot;
5170                let mut position = region.range.start.value.unwrap();
5171                position.add_text_dim(
5172                    &region
5173                        .buffer
5174                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5175                );
5176                if point == region.range.end.key && region.has_trailing_newline {
5177                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5178                }
5179                Some(position)
5180            } else {
5181                Some(MBD::from_summary(&self.text_summary()))
5182            }
5183        })
5184    }
5185
5186    fn excerpts_for_buffer(&self, buffer_id: BufferId) -> impl Iterator<Item = &Excerpt> {
5187        if let Some(path_key) = self.path_keys_by_buffer.get(&buffer_id) {
5188            let mut cursor = self.excerpts.cursor::<PathKey>(());
5189            cursor.seek_forward(path_key, Bias::Left);
5190            Some(iter::from_fn(move || {
5191                let excerpt = cursor.item()?;
5192                if &excerpt.path_key != path_key {
5193                    return None;
5194                }
5195                cursor.next();
5196                Some(excerpt)
5197            }))
5198        } else {
5199            None
5200        }
5201        .into_iter()
5202        .flatten()
5203    }
5204
5205    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5206        self.anchor_at(position, Bias::Left)
5207    }
5208
5209    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5210        self.anchor_at(position, Bias::Right)
5211    }
5212
5213    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5214        let offset = position.to_offset(self);
5215
5216        // Find the given position in the diff transforms. Determine the corresponding
5217        // offset in the excerpts, and whether the position is within a deleted hunk.
5218        let mut diff_transforms = self
5219            .diff_transforms
5220            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5221        diff_transforms.seek(&offset, Bias::Right);
5222
5223        if offset == diff_transforms.start().0
5224            && bias == Bias::Left
5225            && let Some(prev_item) = diff_transforms.prev_item()
5226            && let DiffTransform::DeletedHunk { .. } = prev_item
5227        {
5228            diff_transforms.prev();
5229        }
5230        let offset_in_transform = offset - diff_transforms.start().0;
5231        let mut excerpt_offset = diff_transforms.start().1;
5232        let mut diff_base_anchor = None;
5233        if let Some(DiffTransform::DeletedHunk {
5234            buffer_id,
5235            base_text_byte_range,
5236            has_trailing_newline,
5237            ..
5238        }) = diff_transforms.item()
5239        {
5240            let diff = self.diffs.get(buffer_id).expect("missing diff");
5241            if offset_in_transform > base_text_byte_range.len() {
5242                debug_assert!(*has_trailing_newline);
5243                bias = Bias::Right;
5244            } else {
5245                diff_base_anchor = Some(
5246                    diff.base_text()
5247                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5248                );
5249                bias = Bias::Left;
5250            }
5251        } else {
5252            excerpt_offset += MultiBufferOffset(offset_in_transform);
5253        };
5254
5255        let mut excerpts = self
5256            .excerpts
5257            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5258        excerpts.seek(&excerpt_offset, Bias::Right);
5259        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5260            excerpts.prev();
5261        }
5262        if let Some(excerpt) = excerpts.item() {
5263            let buffer_snapshot = excerpt.buffer_snapshot(self);
5264            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5265            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5266                overshoot -= 1;
5267                bias = Bias::Right;
5268            }
5269
5270            let buffer_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
5271            let text_anchor = excerpt.clip_anchor(
5272                buffer_snapshot.anchor_at(buffer_start + overshoot, bias),
5273                self,
5274            );
5275            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5276            let anchor = match diff_base_anchor {
5277                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5278                None => anchor,
5279            };
5280            anchor.into()
5281        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5282        {
5283            Anchor::min()
5284        } else {
5285            Anchor::max()
5286        }
5287    }
5288
5289    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5290    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5291        let buffer = self.as_singleton()?;
5292        if text_anchor
5293            .buffer_id
5294            .is_none_or(|id| id == buffer.remote_id())
5295        {
5296            // todo!() bit hacky, but always right for singletons
5297            Some(Anchor::in_buffer(PathKeyIndex(0), text_anchor))
5298        } else {
5299            None
5300        }
5301    }
5302
5303    /// Creates a multibuffer anchor range for the given buffer anchor range, if any excerpt contains both endpoints.
5304    pub fn anchor_range_in_buffer(
5305        &self,
5306        buffer_id: BufferId,
5307        text_anchor: Range<text::Anchor>,
5308    ) -> Option<Range<Anchor>> {
5309        for excerpt in self.excerpts_for_buffer(buffer_id) {
5310            let buffer_snapshot = excerpt.buffer_snapshot(self);
5311            if excerpt.range.contains(&text_anchor.start, &buffer_snapshot)
5312                && excerpt.range.contains(&text_anchor.end, &buffer_snapshot)
5313            {
5314                return Some(Anchor::range_in_buffer(excerpt.path_key_index, text_anchor));
5315            }
5316        }
5317
5318        None
5319    }
5320
5321    /// Creates a multibuffer anchor for the given buffer anchor, if it is contained in any excerpt.
5322    pub fn anchor_in_buffer(
5323        &self,
5324        buffer_id: BufferId,
5325        text_anchor: text::Anchor,
5326    ) -> Option<Anchor> {
5327        for excerpt in self.excerpts_for_buffer(buffer_id) {
5328            let buffer_snapshot = excerpt.buffer_snapshot(self);
5329            if excerpt.range.contains(&text_anchor, &buffer_snapshot) {
5330                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5331            }
5332        }
5333
5334        None
5335    }
5336
5337    pub fn anchors_in_buffer(
5338        &self,
5339        buffer_id: BufferId,
5340        text_anchors: impl IntoIterator<Item = text::Anchor>,
5341    ) -> Option<impl Iterator<Item = Anchor>> {
5342        let path_key_index = self.path_key_index_for_buffer(buffer_id)?;
5343        Some(
5344            text_anchors
5345                .into_iter()
5346                .map(move |anchor| Anchor::in_buffer(path_key_index, anchor)),
5347        )
5348    }
5349
5350    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5351        match anchor {
5352            // todo(lw): should be `!self.is_empty()`
5353            Anchor::Min | Anchor::Max => true,
5354            Anchor::Excerpt(excerpt_anchor) => {
5355                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5356                    return false;
5357                };
5358                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5359                cursor.seek(&target, Bias::Left);
5360                let Some(excerpt) = cursor.item() else {
5361                    return false;
5362                };
5363                excerpt
5364                    .buffer_snapshot(self)
5365                    .can_resolve(&excerpt_anchor.text_anchor())
5366            }
5367        }
5368    }
5369
5370    pub fn excerpts(&self) -> impl Iterator<Item = (&BufferSnapshot, ExcerptInfo)> {
5371        self.excerpts
5372            .iter()
5373            .map(|excerpt| (excerpt.buffer_snapshot(self), excerpt.info()))
5374    }
5375
5376    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5377    where
5378        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5379        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5380    {
5381        let excerpts = self.excerpts.cursor(());
5382        let diff_transforms = self.diff_transforms.cursor(());
5383        MultiBufferCursor {
5384            excerpts,
5385            diff_transforms,
5386            cached_region: OnceCell::new(),
5387            snapshot: self,
5388        }
5389    }
5390
5391    pub fn excerpt_before(&self, anchor: Anchor) -> Option<ExcerptInfo> {
5392        let target = anchor.try_seek_target(&self)?;
5393        let mut excerpts = self.excerpts.cursor::<ExcerptSummary>(());
5394        excerpts.seek(&target, Bias::Left);
5395        excerpts.prev();
5396        Some(excerpts.item()?.info())
5397    }
5398
5399    pub fn excerpt_boundaries_in_range<R, T>(
5400        &self,
5401        range: R,
5402    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5403    where
5404        R: RangeBounds<T>,
5405        T: ToOffset,
5406    {
5407        let start_offset;
5408        let start = match range.start_bound() {
5409            Bound::Included(start) => {
5410                start_offset = start.to_offset(self);
5411                Bound::Included(start_offset)
5412            }
5413            Bound::Excluded(_) => {
5414                panic!("not supported")
5415            }
5416            Bound::Unbounded => {
5417                start_offset = MultiBufferOffset::ZERO;
5418                Bound::Unbounded
5419            }
5420        };
5421        let end = match range.end_bound() {
5422            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5423            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5424            Bound::Unbounded => Bound::Unbounded,
5425        };
5426        let bounds = (start, end);
5427        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5428        cursor.seek(&DimensionPair {
5429            key: start_offset,
5430            value: None,
5431        });
5432
5433        if cursor
5434            .fetch_excerpt_with_range()
5435            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5436        {
5437            cursor.prev_excerpt();
5438        } else {
5439            cursor.seek_to_start_of_current_excerpt();
5440        }
5441        let mut prev_excerpt = cursor
5442            .fetch_excerpt_with_range()
5443            .map(|(excerpt, _)| excerpt);
5444
5445        cursor.next_excerpt_forwards();
5446
5447        iter::from_fn(move || {
5448            loop {
5449                if self.singleton {
5450                    return None;
5451                }
5452
5453                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5454                cursor.next_excerpt_forwards();
5455                if !bounds.contains(&next_range.start.key) {
5456                    prev_excerpt = Some(next_excerpt);
5457                    continue;
5458                }
5459
5460                let next_region_start = next_range.start.value.unwrap();
5461                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5462                    range.start.value.unwrap()
5463                } else {
5464                    self.max_point()
5465                };
5466
5467                let prev = prev_excerpt.as_ref().map(|excerpt| ExcerptBoundaryInfo {
5468                    path_key_index: excerpt.path_key_index,
5469                    buffer: excerpt.buffer_snapshot(self).clone(),
5470                    range: excerpt.range.clone(),
5471                    end_row: MultiBufferRow(next_region_start.row),
5472                });
5473
5474                let next = ExcerptBoundaryInfo {
5475                    path_key_index: next_excerpt.path_key_index,
5476                    buffer: next_excerpt.buffer_snapshot(self).clone(),
5477                    range: next_excerpt.range.clone(),
5478                    end_row: if next_excerpt.has_trailing_newline {
5479                        MultiBufferRow(next_region_end.row - 1)
5480                    } else {
5481                        MultiBufferRow(next_region_end.row)
5482                    },
5483                };
5484
5485                let row = MultiBufferRow(next_region_start.row);
5486
5487                prev_excerpt = Some(next_excerpt);
5488
5489                return Some(ExcerptBoundary { row, prev, next });
5490            }
5491        })
5492    }
5493
5494    pub fn edit_count(&self) -> usize {
5495        self.edit_count
5496    }
5497
5498    pub fn non_text_state_update_count(&self) -> usize {
5499        self.non_text_state_update_count
5500    }
5501
5502    /// Returns the smallest enclosing bracket ranges containing the given range or
5503    /// None if no brackets contain range or the range is not contained in a single
5504    /// excerpt
5505    ///
5506    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5507    #[ztracing::instrument(skip_all)]
5508    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5509        &self,
5510        range: Range<T>,
5511        range_filter: Option<
5512            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5513        >,
5514    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5515        let range = range.start.to_offset(self)..range.end.to_offset(self);
5516        let mut excerpt = self.excerpt_containing(range.clone())?;
5517        let buffer_snapshot = excerpt.buffer(self).clone();
5518        let excerpt_buffer_range = excerpt.buffer_range(self);
5519
5520        // Filter to ranges contained in the excerpt
5521        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5522            excerpt_buffer_range.contains(&BufferOffset(open.start))
5523                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5524                && range_filter.is_none_or(|filter| {
5525                    filter(
5526                        &buffer_snapshot,
5527                        BufferOffset(open.start)..BufferOffset(close.end),
5528                        BufferOffset(close.start)..BufferOffset(close.end),
5529                    )
5530                })
5531        };
5532
5533        let (open, close) = buffer_snapshot.innermost_enclosing_bracket_ranges(
5534            excerpt.map_range_to_buffer(range),
5535            Some(&range_filter),
5536        )?;
5537
5538        Some((
5539            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5540            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5541        ))
5542    }
5543
5544    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5545    /// not contained in a single excerpt
5546    pub fn enclosing_bracket_ranges<T: ToOffset>(
5547        &self,
5548        range: Range<T>,
5549    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5550    {
5551        let range = range.start.to_offset(self)..range.end.to_offset(self);
5552        let mut excerpt = self.excerpt_containing(range.clone())?;
5553
5554        Some(
5555            excerpt
5556                .buffer(self)
5557                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5558                .filter_map(move |pair| {
5559                    let open_range =
5560                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5561                    let close_range =
5562                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5563                    if excerpt.contains_buffer_range(open_range.start..close_range.end, self) {
5564                        Some((
5565                            excerpt.map_range_from_buffer(open_range),
5566                            excerpt.map_range_from_buffer(close_range),
5567                        ))
5568                    } else {
5569                        None
5570                    }
5571                }),
5572        )
5573    }
5574
5575    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5576    /// not contained in a single excerpt
5577    pub fn text_object_ranges<T: ToOffset>(
5578        &self,
5579        range: Range<T>,
5580        options: TreeSitterOptions,
5581    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5582        let range = range.start.to_offset(self)..range.end.to_offset(self);
5583        self.excerpt_containing(range.clone())
5584            .map(|mut excerpt| {
5585                excerpt
5586                    .buffer(self)
5587                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5588                    .filter_map(move |(range, text_object)| {
5589                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5590                        if excerpt.contains_buffer_range(range.clone(), self) {
5591                            Some((excerpt.map_range_from_buffer(range), text_object))
5592                        } else {
5593                            None
5594                        }
5595                    })
5596            })
5597            .into_iter()
5598            .flatten()
5599    }
5600
5601    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5602    /// not contained in a single excerpt
5603    pub fn bracket_ranges<T: ToOffset>(
5604        &self,
5605        range: Range<T>,
5606    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5607    {
5608        let range = range.start.to_offset(self)..range.end.to_offset(self);
5609        let mut excerpt = self.excerpt_containing(range.clone())?;
5610        Some(
5611            excerpt
5612                .buffer(self)
5613                .bracket_ranges(excerpt.map_range_to_buffer(range))
5614                .filter_map(move |pair| {
5615                    let open_range =
5616                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5617                    let close_range =
5618                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5619                    excerpt
5620                        .contains_buffer_range(open_range.start..close_range.end, self)
5621                        .then(|| BracketMatch {
5622                            open_range: excerpt.map_range_from_buffer(open_range),
5623                            close_range: excerpt.map_range_from_buffer(close_range),
5624                            color_index: pair.color_index,
5625                            newline_only: pair.newline_only,
5626                            syntax_layer_depth: pair.syntax_layer_depth,
5627                        })
5628                })
5629                .map(BracketMatch::bracket_ranges),
5630        )
5631    }
5632
5633    pub fn redacted_ranges<'a, T: ToOffset>(
5634        &'a self,
5635        range: Range<T>,
5636        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5637    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5638        let range = range.start.to_offset(self)..range.end.to_offset(self);
5639        self.lift_buffer_metadata(range, move |buffer, range| {
5640            if redaction_enabled(buffer.file()) {
5641                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5642            } else {
5643                None
5644            }
5645        })
5646        .map(|(range, _, _)| range)
5647    }
5648
5649    pub fn runnable_ranges(
5650        &self,
5651        range: Range<Anchor>,
5652    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5653        let range = range.start.to_offset(self)..range.end.to_offset(self);
5654        self.lift_buffer_metadata(range, move |buffer, range| {
5655            Some(
5656                buffer
5657                    .runnable_ranges(range.clone())
5658                    .filter(move |runnable| {
5659                        runnable.run_range.start >= range.start
5660                            && runnable.run_range.end < range.end
5661                    })
5662                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5663            )
5664        })
5665        .map(|(run_range, runnable, _)| (run_range, runnable))
5666    }
5667
5668    pub fn line_indents(
5669        &self,
5670        start_row: MultiBufferRow,
5671        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5672    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5673        let max_point = self.max_point();
5674        let mut cursor = self.cursor::<Point, Point>();
5675        cursor.seek(&Point::new(start_row.0, 0));
5676        iter::from_fn(move || {
5677            let mut region = cursor.region()?;
5678            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5679                cursor.next();
5680                region = cursor.region()?;
5681            }
5682            let region = cursor.region()?;
5683            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5684            let buffer_start_row =
5685                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5686
5687            let buffer_end_row = if region.is_main_buffer
5688                && (region.has_trailing_newline || region.range.end == max_point)
5689            {
5690                region.buffer_range.end.row
5691            } else {
5692                region.buffer_range.end.row.saturating_sub(1)
5693            };
5694
5695            let line_indents = region
5696                .buffer
5697                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5698            let region_buffer_row = region.buffer_range.start.row;
5699            let region_row = region.range.start.row;
5700            let region_buffer = region.excerpt.buffer_snapshot(self);
5701            cursor.next();
5702            Some(line_indents.map(move |(buffer_row, indent)| {
5703                let row = region_row + (buffer_row - region_buffer_row);
5704                (MultiBufferRow(row), indent, region_buffer)
5705            }))
5706        })
5707        .flatten()
5708    }
5709
5710    pub fn reversed_line_indents(
5711        &self,
5712        end_row: MultiBufferRow,
5713        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5714    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5715        let max_point = self.max_point();
5716        let mut cursor = self.cursor::<Point, Point>();
5717        cursor.seek(&Point::new(end_row.0, 0));
5718        iter::from_fn(move || {
5719            let mut region = cursor.region()?;
5720            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5721                cursor.prev();
5722                region = cursor.region()?;
5723            }
5724            let region = cursor.region()?;
5725
5726            let buffer_start_row = region.buffer_range.start.row;
5727            let buffer_end_row = if region.is_main_buffer
5728                && (region.has_trailing_newline || region.range.end == max_point)
5729            {
5730                region.buffer_range.end.row + 1
5731            } else {
5732                region.buffer_range.end.row
5733            };
5734
5735            let overshoot = end_row.0 - region.range.start.row;
5736            let buffer_end_row =
5737                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5738
5739            let line_indents = region
5740                .buffer
5741                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5742            let region_buffer_row = region.buffer_range.start.row;
5743            let region_row = region.range.start.row;
5744            let region_buffer = region.excerpt.buffer_snapshot(self);
5745            cursor.prev();
5746            Some(line_indents.map(move |(buffer_row, indent)| {
5747                let row = region_row + (buffer_row - region_buffer_row);
5748                (MultiBufferRow(row), indent, region_buffer)
5749            }))
5750        })
5751        .flatten()
5752    }
5753
5754    pub async fn enclosing_indent(
5755        &self,
5756        mut target_row: MultiBufferRow,
5757    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5758        let max_row = MultiBufferRow(self.max_point().row);
5759        if target_row >= max_row {
5760            return None;
5761        }
5762
5763        let mut target_indent = self.line_indent_for_row(target_row);
5764
5765        // If the current row is at the start of an indented block, we want to return this
5766        // block as the enclosing indent.
5767        if !target_indent.is_line_empty() && target_row < max_row {
5768            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5769            if !next_line_indent.is_line_empty()
5770                && target_indent.raw_len() < next_line_indent.raw_len()
5771            {
5772                target_indent = next_line_indent;
5773                target_row.0 += 1;
5774            }
5775        }
5776
5777        const SEARCH_ROW_LIMIT: u32 = 25000;
5778        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5779        const YIELD_INTERVAL: u32 = 100;
5780
5781        let mut accessed_row_counter = 0;
5782
5783        // If there is a blank line at the current row, search for the next non indented lines
5784        if target_indent.is_line_empty() {
5785            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5786            let end =
5787                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5788
5789            let mut non_empty_line_above = None;
5790            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5791                if row < start {
5792                    break;
5793                }
5794                accessed_row_counter += 1;
5795                if accessed_row_counter == YIELD_INTERVAL {
5796                    accessed_row_counter = 0;
5797                    yield_now().await;
5798                }
5799                if !indent.is_line_empty() {
5800                    non_empty_line_above = Some((row, indent));
5801                    break;
5802                }
5803            }
5804
5805            let mut non_empty_line_below = None;
5806            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5807                if row > end {
5808                    break;
5809                }
5810                accessed_row_counter += 1;
5811                if accessed_row_counter == YIELD_INTERVAL {
5812                    accessed_row_counter = 0;
5813                    yield_now().await;
5814                }
5815                if !indent.is_line_empty() {
5816                    non_empty_line_below = Some((row, indent));
5817                    break;
5818                }
5819            }
5820
5821            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5822                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5823                    if above_indent.raw_len() >= below_indent.raw_len() {
5824                        (above_row, above_indent)
5825                    } else {
5826                        (below_row, below_indent)
5827                    }
5828                }
5829                (Some(above), None) => above,
5830                (None, Some(below)) => below,
5831                _ => return None,
5832            };
5833
5834            target_indent = indent;
5835            target_row = row;
5836        }
5837
5838        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5839        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5840
5841        let mut start_indent = None;
5842        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5843            if row < start {
5844                break;
5845            }
5846            accessed_row_counter += 1;
5847            if accessed_row_counter == YIELD_INTERVAL {
5848                accessed_row_counter = 0;
5849                yield_now().await;
5850            }
5851            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5852                start_indent = Some((row, indent));
5853                break;
5854            }
5855        }
5856        let (start_row, start_indent_size) = start_indent?;
5857
5858        let mut end_indent = (end, None);
5859        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5860            if row > end {
5861                break;
5862            }
5863            accessed_row_counter += 1;
5864            if accessed_row_counter == YIELD_INTERVAL {
5865                accessed_row_counter = 0;
5866                yield_now().await;
5867            }
5868            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5869                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5870                break;
5871            }
5872        }
5873        let (end_row, end_indent_size) = end_indent;
5874
5875        let indent = if let Some(end_indent_size) = end_indent_size {
5876            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5877                start_indent_size
5878            } else {
5879                end_indent_size
5880            }
5881        } else {
5882            start_indent_size
5883        };
5884
5885        Some((start_row..end_row, indent))
5886    }
5887
5888    pub fn indent_guides_in_range<T: ToPoint>(
5889        &self,
5890        range: Range<T>,
5891        ignore_disabled_for_language: bool,
5892        cx: &App,
5893    ) -> impl Iterator<Item = IndentGuide> {
5894        let range = range.start.to_point(self)..range.end.to_point(self);
5895        let start_row = MultiBufferRow(range.start.row);
5896        let end_row = MultiBufferRow(range.end.row);
5897
5898        let mut row_indents = self.line_indents(start_row, |buffer| {
5899            let settings =
5900                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5901            settings.indent_guides.enabled || ignore_disabled_for_language
5902        });
5903
5904        let mut result = Vec::new();
5905        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5906
5907        let mut prev_settings = None;
5908        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5909            if first_row > end_row {
5910                break;
5911            }
5912            let current_depth = indent_stack.len() as u32;
5913
5914            // Avoid retrieving the language settings repeatedly for every buffer row.
5915            if let Some((prev_buffer_id, _)) = &prev_settings
5916                && prev_buffer_id != &buffer.remote_id()
5917            {
5918                prev_settings.take();
5919            }
5920            let settings = &prev_settings
5921                .get_or_insert_with(|| {
5922                    (
5923                        buffer.remote_id(),
5924                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5925                    )
5926                })
5927                .1;
5928            let tab_size = settings.tab_size.get();
5929
5930            // When encountering empty, continue until found useful line indent
5931            // then add to the indent stack with the depth found
5932            let mut found_indent = false;
5933            let mut last_row = first_row;
5934            if line_indent.is_line_blank() {
5935                while !found_indent {
5936                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5937                        break;
5938                    };
5939                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5940                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5941                        break;
5942                    }
5943
5944                    if new_line_indent.is_line_blank() {
5945                        continue;
5946                    }
5947                    last_row = target_row.min(end_row);
5948                    line_indent = new_line_indent;
5949                    found_indent = true;
5950                    break;
5951                }
5952            } else {
5953                found_indent = true
5954            }
5955
5956            let depth = if found_indent {
5957                line_indent.len(tab_size) / tab_size
5958            } else {
5959                0
5960            };
5961
5962            match depth.cmp(&current_depth) {
5963                cmp::Ordering::Less => {
5964                    for _ in 0..(current_depth - depth) {
5965                        let mut indent = indent_stack.pop().unwrap();
5966                        if last_row != first_row {
5967                            // In this case, we landed on an empty row, had to seek forward,
5968                            // and discovered that the indent we where on is ending.
5969                            // This means that the last display row must
5970                            // be on line that ends this indent range, so we
5971                            // should display the range up to the first non-empty line
5972                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5973                        }
5974
5975                        result.push(indent)
5976                    }
5977                }
5978                cmp::Ordering::Greater => {
5979                    for next_depth in current_depth..depth {
5980                        indent_stack.push(IndentGuide {
5981                            buffer_id: buffer.remote_id(),
5982                            start_row: first_row,
5983                            end_row: last_row,
5984                            depth: next_depth,
5985                            tab_size,
5986                            settings: settings.indent_guides.clone(),
5987                        });
5988                    }
5989                }
5990                _ => {}
5991            }
5992
5993            for indent in indent_stack.iter_mut() {
5994                indent.end_row = last_row;
5995            }
5996        }
5997
5998        result.extend(indent_stack);
5999        result.into_iter()
6000    }
6001
6002    pub fn trailing_excerpt_update_count(&self) -> usize {
6003        self.trailing_excerpt_update_count
6004    }
6005
6006    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6007        self.point_to_buffer_offset(point)
6008            .and_then(|(buffer, _)| buffer.file())
6009    }
6010
6011    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6012        self.point_to_buffer_offset(offset)
6013            .and_then(|(buffer, offset)| buffer.language_at(offset))
6014    }
6015
6016    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6017        self.excerpts
6018            .first()
6019            .map(|excerpt| excerpt.buffer_snapshot(self))
6020            .map(|buffer| {
6021                language_settings(
6022                    buffer.language().map(|language| language.name()),
6023                    buffer.file(),
6024                    cx,
6025                )
6026            })
6027            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6028    }
6029
6030    pub fn language_settings_at<'a, T: ToOffset>(
6031        &'a self,
6032        point: T,
6033        cx: &'a App,
6034    ) -> Cow<'a, LanguageSettings> {
6035        let mut language = None;
6036        let mut file = None;
6037        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6038            language = buffer.language_at(offset);
6039            file = buffer.file();
6040        }
6041        language_settings(language.map(|l| l.name()), file, cx)
6042    }
6043
6044    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6045        self.point_to_buffer_offset(point)
6046            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6047    }
6048
6049    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6050        self.point_to_buffer_offset(point)
6051            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6052            .unwrap_or_default()
6053    }
6054
6055    pub fn language_indent_size_at<T: ToOffset>(
6056        &self,
6057        position: T,
6058        cx: &App,
6059    ) -> Option<IndentSize> {
6060        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6061        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6062    }
6063
6064    pub fn is_dirty(&self) -> bool {
6065        self.is_dirty
6066    }
6067
6068    pub fn has_deleted_file(&self) -> bool {
6069        self.has_deleted_file
6070    }
6071
6072    pub fn has_conflict(&self) -> bool {
6073        self.has_conflict
6074    }
6075
6076    pub fn has_diagnostics(&self) -> bool {
6077        self.excerpts
6078            .iter()
6079            .any(|excerpt| excerpt.buffer_snapshot(self).has_diagnostics())
6080    }
6081
6082    pub fn diagnostic_group(
6083        &self,
6084        buffer_id: BufferId,
6085        group_id: usize,
6086    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6087        self.lift_buffer_metadata::<Point, _, _>(
6088            Point::zero()..self.max_point(),
6089            move |buffer, range| {
6090                if buffer.remote_id() != buffer_id {
6091                    return None;
6092                };
6093                Some(
6094                    buffer
6095                        .diagnostics_in_range(range, false)
6096                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6097                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6098                )
6099            },
6100        )
6101        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6102    }
6103
6104    pub fn diagnostics_in_range<'a, MBD>(
6105        &'a self,
6106        range: Range<MBD>,
6107    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6108    where
6109        MBD::TextDimension: 'a
6110            + text::ToOffset
6111            + text::FromAnchor
6112            + Sub<Output = MBD::TextDimension>
6113            + fmt::Debug
6114            + ops::Add<Output = MBD::TextDimension>
6115            + ops::AddAssign
6116            + Ord,
6117        MBD: MultiBufferDimension
6118            + Ord
6119            + Sub<Output = MBD::TextDimension>
6120            + ops::Add<MBD::TextDimension, Output = MBD>
6121            + ops::AddAssign<MBD::TextDimension>
6122            + 'a,
6123    {
6124        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6125            Some(
6126                buffer
6127                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6128                    .map(|entry| (entry.range, entry.diagnostic)),
6129            )
6130        })
6131        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6132    }
6133
6134    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6135        &'a self,
6136        range: Range<MBD>,
6137    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6138    where
6139        MBD: MultiBufferDimension
6140            + Ord
6141            + Sub<Output = MBD::TextDimension>
6142            + ops::Add<MBD::TextDimension, Output = MBD>
6143            + ops::AddAssign<MBD::TextDimension>,
6144        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6145            + ops::Add<Output = MBD::TextDimension>
6146            + text::ToOffset
6147            + text::FromAnchor
6148            + AddAssign<MBD::TextDimension>
6149            + Ord,
6150    {
6151        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6152            Some(
6153                buffer
6154                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6155                    .map(|entry| (entry.range, entry.diagnostic)),
6156            )
6157        })
6158        .map(|(range, diagnostic, excerpt)| {
6159            (
6160                excerpt.buffer_snapshot(self).remote_id(),
6161                DiagnosticEntryRef { diagnostic, range },
6162            )
6163        })
6164    }
6165
6166    pub fn syntax_ancestor<T: ToOffset>(
6167        &self,
6168        range: Range<T>,
6169    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6170        let range = range.start.to_offset(self)..range.end.to_offset(self);
6171        let mut excerpt = self.excerpt_containing(range.clone())?;
6172        let node = excerpt
6173            .buffer(self)
6174            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6175        let node_range = node.byte_range();
6176        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6177        if !excerpt.contains_buffer_range(node_range.clone(), self) {
6178            return None;
6179        };
6180        Some((node, excerpt.map_range_from_buffer(node_range)))
6181    }
6182
6183    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6184        let buffer = self.as_singleton()?;
6185        let outline = buffer.outline(theme);
6186        Some(Outline::new(
6187            outline
6188                .items
6189                .into_iter()
6190                .flat_map(|item| {
6191                    Some(OutlineItem {
6192                        depth: item.depth,
6193                        range: self.anchor_range_in_buffer(buffer.remote_id(), item.range)?,
6194                        source_range_for_text: self.anchor_range_in_buffer(
6195                            buffer.remote_id(),
6196                            item.source_range_for_text,
6197                        )?,
6198                        text: item.text,
6199                        highlight_ranges: item.highlight_ranges,
6200                        name_ranges: item.name_ranges,
6201                        body_range: item.body_range.and_then(|body_range| {
6202                            self.anchor_range_in_buffer(buffer.remote_id(), body_range)
6203                        }),
6204                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6205                            self.anchor_range_in_buffer(buffer.remote_id(), annotation_range)
6206                        }),
6207                    })
6208                })
6209                .collect(),
6210        ))
6211    }
6212
6213    pub fn symbols_containing<T: ToOffset>(
6214        &self,
6215        offset: T,
6216        theme: Option<&SyntaxTheme>,
6217    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6218        let anchor = self.anchor_before(offset);
6219        let target = anchor.try_seek_target(&self)?;
6220        let (_, _, excerpt) = self.excerpts.find((), &target, Bias::Left);
6221        let excerpt = excerpt?;
6222        let buffer_snapshot = excerpt.buffer_snapshot(self);
6223        Some((
6224            buffer_snapshot.remote_id(),
6225            buffer_snapshot
6226                .symbols_containing(
6227                    anchor
6228                        .excerpt_anchor()
6229                        .map(|anchor| anchor.text_anchor())
6230                        .unwrap_or(text::Anchor::MIN),
6231                    theme,
6232                )
6233                .into_iter()
6234                .flat_map(|item| {
6235                    Some(OutlineItem {
6236                        depth: item.depth,
6237                        source_range_for_text: Anchor::range_in_buffer(
6238                            excerpt.path_key_index,
6239                            item.source_range_for_text,
6240                        ),
6241                        range: Anchor::range_in_buffer(excerpt.path_key_index, item.range),
6242                        text: item.text,
6243                        highlight_ranges: item.highlight_ranges,
6244                        name_ranges: item.name_ranges,
6245                        body_range: item.body_range.map(|body_range| {
6246                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6247                        }),
6248                        annotation_range: item.annotation_range.map(|body_range| {
6249                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6250                        }),
6251                    })
6252                })
6253                .collect(),
6254        ))
6255    }
6256
6257    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6258        let (_, _, excerpt) = self
6259            .excerpts
6260            .find::<ExcerptSummary, _>((), path, Bias::Left);
6261        Some(excerpt?.buffer_snapshot(self))
6262    }
6263
6264    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6265        self.path_keys_by_buffer.get(&buffer_id)
6266    }
6267
6268    pub fn path_key_index_for_buffer(&self, buffer_id: BufferId) -> Option<PathKeyIndex> {
6269        self.first_excerpt_for_buffer(buffer_id)
6270            .map(|excerpt| excerpt.path_key_index)
6271    }
6272
6273    pub fn first_excerpt_for_buffer(&self, buffer_id: BufferId) -> Option<&Excerpt> {
6274        let path_key = self.path_keys_by_buffer.get(&buffer_id)?;
6275        self.first_excerpt_for_path(&path_key)
6276    }
6277
6278    pub fn first_excerpt_for_path(&self, path_key: &PathKey) -> Option<&Excerpt> {
6279        let (_, _, first_excerpt) =
6280            self.excerpts
6281                .find::<ExcerptSummary, _>((), path_key, Bias::Left);
6282        first_excerpt
6283    }
6284
6285    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6286        self.buffer_for_path(self.path_keys_by_buffer.get(&id)?)
6287    }
6288
6289    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6290        self.path_keys_by_index.get(&anchor.path).cloned()
6291    }
6292
6293    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6294        self.try_path_for_anchor(anchor)
6295            .expect("invalid anchor: path was never added to multibuffer")
6296    }
6297
6298    // todo!() this may not make sense any more
6299    pub fn range_for_excerpt(&self, excerpt_id: BufferId) -> Option<Range<Point>> {
6300        todo!()
6301        // let mut cursor = self
6302        //     .excerpts
6303        //     .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6304        // let locator = self.excerpt_locator_for_id(excerpt_id);
6305        // let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6306        // if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6307        //     sought_exact = true;
6308        //     cursor.prev();
6309        // } else if excerpt_id == ExcerptId::min() {
6310        //     sought_exact = true;
6311        // }
6312        // if sought_exact {
6313        //     let start = cursor.start().1;
6314        //     let end = cursor.end().1;
6315        //     let mut diff_transforms = self
6316        //         .diff_transforms
6317        //         .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6318        //     diff_transforms.seek(&start, Bias::Left);
6319        //     let overshoot = start - diff_transforms.start().0;
6320        //     let start = diff_transforms.start().1 + overshoot;
6321        //     diff_transforms.seek(&end, Bias::Right);
6322        //     let overshoot = end - diff_transforms.start().0;
6323        //     let end = diff_transforms.start().1 + overshoot;
6324        //     Some(start.0..end.0)
6325        // } else {
6326        //     None
6327        // }
6328    }
6329
6330    // todo!() sort out excerpt_containing etc.
6331    fn excerpt_at(&self, _position: impl ToOffset) -> Option<&Excerpt> {
6332        todo!()
6333    }
6334
6335    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6336    pub fn excerpt_containing<T: ToOffset>(
6337        &self,
6338        range: Range<T>,
6339    ) -> Option<MultiBufferExcerpt<'_>> {
6340        let range = range.start.to_offset(self)..range.end.to_offset(self);
6341        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6342        cursor.seek(&range.start);
6343
6344        let start_excerpt = cursor.excerpt()?;
6345        if range.end != range.start {
6346            cursor.seek_forward(&range.end);
6347            if cursor.excerpt()? != start_excerpt {
6348                return None;
6349            }
6350        }
6351
6352        cursor.seek_to_start_of_current_excerpt();
6353        let region = cursor.region()?;
6354        let offset = region.range.start;
6355        let buffer_offset = start_excerpt.buffer_start_offset(self);
6356        let excerpt_offset = *cursor.excerpts.start();
6357        Some(MultiBufferExcerpt {
6358            diff_transforms: cursor.diff_transforms,
6359            excerpt: start_excerpt,
6360            offset,
6361            buffer_offset,
6362            excerpt_offset,
6363        })
6364    }
6365
6366    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6367        match anchor {
6368            Anchor::Min => self.excerpts.first().map(|excerpt| excerpt.buffer_id),
6369            Anchor::Excerpt(excerpt_anchor) => Some(excerpt_anchor.buffer_id),
6370            Anchor::Max => self.excerpts.last().map(|excerpt| excerpt.buffer_id),
6371        }
6372    }
6373
6374    pub fn selections_in_range<'a>(
6375        &'a self,
6376        range: &'a Range<Anchor>,
6377        include_local: bool,
6378    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6379        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6380        cursor.seek(&range.start.seek_target(self), Bias::Left);
6381        cursor
6382            .take_while(move |excerpt| {
6383                let excerpt_start =
6384                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6385                excerpt_start.cmp(&range.end, self).is_le()
6386            })
6387            .flat_map(move |excerpt| {
6388                let buffer_snapshot = excerpt.buffer_snapshot(self);
6389                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6390                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6391                    && excerpt.contains(&excerpt_anchor, self)
6392                {
6393                    query_range.start = excerpt_anchor.text_anchor();
6394                }
6395                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6396                    && excerpt.contains(&excerpt_anchor, self)
6397                {
6398                    query_range.end = excerpt_anchor.text_anchor();
6399                }
6400
6401                buffer_snapshot
6402                    .selections_in_range(query_range, include_local)
6403                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6404                        selections.map(move |selection| {
6405                            let mut start =
6406                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6407                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6408                            if range.start.cmp(&start, self).is_gt() {
6409                                start = range.start;
6410                            }
6411                            if range.end.cmp(&end, self).is_lt() {
6412                                end = range.end;
6413                            }
6414
6415                            (
6416                                replica_id,
6417                                line_mode,
6418                                cursor_shape,
6419                                Selection {
6420                                    id: selection.id,
6421                                    start,
6422                                    end,
6423                                    reversed: selection.reversed,
6424                                    goal: selection.goal,
6425                                },
6426                            )
6427                        })
6428                    })
6429            })
6430    }
6431
6432    pub fn show_headers(&self) -> bool {
6433        self.show_headers
6434    }
6435
6436    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6437        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6438    }
6439
6440    pub fn all_diff_hunks_expanded(&self) -> bool {
6441        self.all_diff_hunks_expanded
6442    }
6443
6444    /// Visually annotates a position or range with the `Debug` representation of a value. The
6445    /// callsite of this function is used as a key - previous annotations will be removed.
6446    #[cfg(debug_assertions)]
6447    #[track_caller]
6448    pub fn debug<V, R>(&self, ranges: &R, value: V)
6449    where
6450        R: debug::ToMultiBufferDebugRanges,
6451        V: std::fmt::Debug,
6452    {
6453        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6454    }
6455
6456    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6457    /// debug annotations with the same key will be removed. The key is also used to determine the
6458    /// annotation's color.
6459    #[cfg(debug_assertions)]
6460    #[track_caller]
6461    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6462    where
6463        K: std::hash::Hash + 'static,
6464        R: debug::ToMultiBufferDebugRanges,
6465        V: std::fmt::Debug,
6466    {
6467        let text_ranges = ranges
6468            .to_multi_buffer_debug_ranges(self)
6469            .into_iter()
6470            .flat_map(|range| {
6471                self.range_to_buffer_ranges(range.start..=range.end)
6472                    .into_iter()
6473                    .map(|(buffer, range)| {
6474                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6475                    })
6476            })
6477            .collect();
6478        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6479            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6480        });
6481    }
6482
6483    fn excerpt_edits_for_diff_change(
6484        &self,
6485        path: &PathKey,
6486        diff_change_range: Range<usize>,
6487    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6488        let mut excerpt_edits = Vec::new();
6489        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6490        cursor.seek(path, Bias::Left);
6491        while let Some(excerpt) = cursor.item()
6492            && &excerpt.path_key == path
6493        {
6494            let buffer_snapshot = excerpt.buffer_snapshot(self);
6495            let excerpt_buffer_range = excerpt.range.context.to_offset(buffer_snapshot);
6496            let excerpt_start = cursor.start().clone();
6497            let excerpt_len = excerpt.text_summary.len;
6498            cursor.next();
6499            if diff_change_range.end < excerpt_buffer_range.start
6500                || diff_change_range.start > excerpt_buffer_range.end
6501            {
6502                continue;
6503            }
6504            let diff_change_start_in_excerpt = diff_change_range
6505                .start
6506                .saturating_sub(excerpt_buffer_range.start);
6507            let diff_change_end_in_excerpt = diff_change_range
6508                .end
6509                .saturating_sub(excerpt_buffer_range.start);
6510            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6511            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6512            excerpt_edits.push(Edit {
6513                old: edit_start..edit_end,
6514                new: edit_start..edit_end,
6515            });
6516        }
6517        excerpt_edits
6518    }
6519
6520    fn excerpts_for_path<'a>(
6521        &'a self,
6522        path_key: &'a PathKey,
6523    ) -> impl Iterator<Item = ExcerptInfo> + 'a {
6524        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6525        cursor.seek(path_key, Bias::Left);
6526        cursor
6527            .take_while(move |item| &item.path_key == path_key)
6528            .map(|excerpt| excerpt.info())
6529    }
6530}
6531
6532#[cfg(any(test, feature = "test-support"))]
6533impl MultiBufferSnapshot {
6534    pub fn random_byte_range(
6535        &self,
6536        start_offset: MultiBufferOffset,
6537        rng: &mut impl rand::Rng,
6538    ) -> Range<MultiBufferOffset> {
6539        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6540        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6541        start..end
6542    }
6543
6544    #[cfg(any(test, feature = "test-support"))]
6545    fn check_invariants(&self) {
6546        let excerpts = self.excerpts.items(());
6547
6548        let all_buffer_path_keys = HashSet::from_iter(self.path_keys_by_buffer.values().cloned());
6549        let all_excerpt_path_keys = HashSet::from_iter(excerpts.iter().map(|e| e.path_key.clone()));
6550
6551        for (ix, excerpt) in excerpts.iter().enumerate() {
6552            if ix > 0 {
6553                let prev = &excerpts[ix - 1];
6554
6555                if excerpt.path_key < prev.path_key {
6556                    panic!("excerpt path_keys are out-of-order: {:?}", excerpts);
6557                } else if excerpt.path_key == prev.path_key {
6558                    if excerpt
6559                        .start_anchor()
6560                        .cmp(&prev.end_anchor(), &self)
6561                        .is_le()
6562                    {
6563                        panic!("excerpt anchors are out-of-order: {:?}", excerpts);
6564                    }
6565                    if excerpt
6566                        .start_anchor()
6567                        .cmp(&excerpt.end_anchor(), &self)
6568                        .is_ge()
6569                    {
6570                        panic!("excerpt with backward range: {:?}", excerpts);
6571                    }
6572                }
6573            }
6574            assert!(
6575                all_buffer_path_keys.contains(&excerpt.path_key),
6576                "excerpt path key not found in active path keys: {:?}",
6577                excerpt.path_key
6578            );
6579            assert_eq!(
6580                self.path_keys_by_index.get(&excerpt.path_key_index),
6581                Some(&excerpt.path_key),
6582                "excerpt path key index does not match path key: {:?}",
6583                excerpt.path_key,
6584            );
6585        }
6586        assert_eq!(all_buffer_path_keys, all_excerpt_path_keys);
6587
6588        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6589            panic!(
6590                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6591                self.excerpts.summary().text,
6592                self.diff_transforms.summary().input,
6593                self.diff_transforms.items(()),
6594            );
6595        }
6596
6597        let mut prev_transform: Option<&DiffTransform> = None;
6598        for item in self.diff_transforms.iter() {
6599            if let DiffTransform::BufferContent {
6600                summary,
6601                inserted_hunk_info,
6602            } = item
6603            {
6604                if let Some(DiffTransform::BufferContent {
6605                    inserted_hunk_info: prev_inserted_hunk_info,
6606                    ..
6607                }) = prev_transform
6608                    && *inserted_hunk_info == *prev_inserted_hunk_info
6609                {
6610                    panic!(
6611                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6612                        self.diff_transforms.items(())
6613                    );
6614                }
6615                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6616                    panic!("empty buffer content transform");
6617                }
6618            }
6619            prev_transform = Some(item);
6620        }
6621    }
6622}
6623
6624impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6625where
6626    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6627    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6628{
6629    #[instrument(skip_all)]
6630    fn seek(&mut self, position: &MBD) {
6631        let position = OutputDimension(*position);
6632        self.cached_region.take();
6633        self.diff_transforms.seek(&position, Bias::Right);
6634        if self.diff_transforms.item().is_none()
6635            && self.diff_transforms.start().output_dimension == position
6636        {
6637            self.diff_transforms.prev();
6638        }
6639
6640        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6641        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6642            let overshoot = position - self.diff_transforms.start().output_dimension;
6643            excerpt_position += overshoot;
6644        }
6645
6646        self.excerpts.seek(&excerpt_position, Bias::Right);
6647        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6648            self.excerpts.prev();
6649        }
6650    }
6651
6652    fn seek_forward(&mut self, position: &MBD) {
6653        let position = OutputDimension(*position);
6654        self.cached_region.take();
6655        self.diff_transforms.seek_forward(&position, Bias::Right);
6656        if self.diff_transforms.item().is_none()
6657            && self.diff_transforms.start().output_dimension == position
6658        {
6659            self.diff_transforms.prev();
6660        }
6661
6662        let overshoot = position - self.diff_transforms.start().output_dimension;
6663        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6664        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6665            excerpt_position += overshoot;
6666        }
6667
6668        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6669        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6670            self.excerpts.prev();
6671        }
6672    }
6673
6674    fn next_excerpt(&mut self) {
6675        self.excerpts.next();
6676        self.seek_to_start_of_current_excerpt();
6677    }
6678
6679    fn prev_excerpt(&mut self) {
6680        self.excerpts.prev();
6681        self.seek_to_start_of_current_excerpt();
6682    }
6683
6684    fn seek_to_start_of_current_excerpt(&mut self) {
6685        self.cached_region.take();
6686
6687        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6688            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6689            && self.diff_transforms.next_item().is_some()
6690        {
6691            self.diff_transforms.next();
6692        }
6693    }
6694
6695    fn next_excerpt_forwards(&mut self) {
6696        self.excerpts.next();
6697        self.seek_to_start_of_current_excerpt_forward();
6698    }
6699
6700    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6701        self.cached_region.take();
6702
6703        if self
6704            .diff_transforms
6705            .seek_forward(self.excerpts.start(), Bias::Left)
6706            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6707            && self.diff_transforms.next_item().is_some()
6708        {
6709            self.diff_transforms.next();
6710        }
6711    }
6712
6713    fn next(&mut self) {
6714        self.cached_region.take();
6715        match self
6716            .diff_transforms
6717            .end()
6718            .excerpt_dimension
6719            .cmp(&self.excerpts.end())
6720        {
6721            cmp::Ordering::Less => self.diff_transforms.next(),
6722            cmp::Ordering::Greater => self.excerpts.next(),
6723            cmp::Ordering::Equal => {
6724                self.diff_transforms.next();
6725                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6726                    || self.diff_transforms.item().is_none()
6727                {
6728                    self.excerpts.next();
6729                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6730                    self.diff_transforms.item()
6731                    && self
6732                        .excerpts
6733                        .item()
6734                        .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end)
6735                {
6736                    self.excerpts.next();
6737                }
6738            }
6739        }
6740    }
6741
6742    fn prev(&mut self) {
6743        self.cached_region.take();
6744        match self
6745            .diff_transforms
6746            .start()
6747            .excerpt_dimension
6748            .cmp(self.excerpts.start())
6749        {
6750            cmp::Ordering::Less => self.excerpts.prev(),
6751            cmp::Ordering::Greater => self.diff_transforms.prev(),
6752            cmp::Ordering::Equal => {
6753                self.diff_transforms.prev();
6754                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6755                    || self.diff_transforms.item().is_none()
6756                {
6757                    self.excerpts.prev();
6758                }
6759            }
6760        }
6761    }
6762
6763    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
6764        self.cached_region
6765            .get_or_init(|| self.build_region())
6766            .as_ref()
6767    }
6768
6769    fn is_at_start_of_excerpt(&mut self) -> bool {
6770        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6771            return false;
6772        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6773            return true;
6774        }
6775
6776        self.diff_transforms.prev();
6777        let prev_transform = self.diff_transforms.item();
6778        self.diff_transforms.next();
6779
6780        prev_transform.is_none_or(|next_transform| {
6781            matches!(next_transform, DiffTransform::BufferContent { .. })
6782        })
6783    }
6784
6785    fn is_at_end_of_excerpt(&self) -> bool {
6786        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6787            return false;
6788        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6789            || self.diff_transforms.item().is_none()
6790        {
6791            return true;
6792        }
6793
6794        let next_transform = self.diff_transforms.next_item();
6795        next_transform.is_none_or(|next_transform| match next_transform {
6796            DiffTransform::BufferContent { .. } => true,
6797            DiffTransform::DeletedHunk { hunk_info, .. } => self
6798                .excerpts
6799                .item()
6800                .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end),
6801        })
6802    }
6803
6804    fn main_buffer_position(&self) -> Option<BD> {
6805        let excerpt = self.excerpts.item()?;
6806        let buffer = excerpt.buffer_snapshot(self.snapshot);
6807        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6808        let mut buffer_start = buffer_context_start;
6809        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6810        buffer_start += overshoot;
6811        Some(buffer_start)
6812    }
6813
6814    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6815        let excerpt = self.excerpts.item()?;
6816        match self.diff_transforms.item()? {
6817            DiffTransform::DeletedHunk {
6818                buffer_id,
6819                base_text_byte_range,
6820                has_trailing_newline,
6821                hunk_info,
6822                ..
6823            } => {
6824                let diff = self.snapshot.diffs.get(buffer_id)?;
6825                let buffer = diff.base_text();
6826                let mut rope_cursor = buffer.as_rope().cursor(0);
6827                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6828                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6829                let mut buffer_end = buffer_start;
6830                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6831                let start = self.diff_transforms.start().output_dimension.0;
6832                let end = self.diff_transforms.end().output_dimension.0;
6833                Some(MultiBufferRegion {
6834                    buffer,
6835                    excerpt,
6836                    has_trailing_newline: *has_trailing_newline,
6837                    is_main_buffer: false,
6838                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6839                        hunk_info.hunk_secondary_status,
6840                    )),
6841                    buffer_range: buffer_start..buffer_end,
6842                    range: start..end,
6843                })
6844            }
6845            DiffTransform::BufferContent {
6846                inserted_hunk_info, ..
6847            } => {
6848                let buffer = excerpt.buffer_snapshot(self.snapshot);
6849                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6850
6851                let mut start = self.diff_transforms.start().output_dimension.0;
6852                let mut buffer_start = buffer_context_start;
6853                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6854                    let overshoot =
6855                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6856                    start += overshoot;
6857                } else {
6858                    let overshoot =
6859                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6860                    buffer_start += overshoot;
6861                }
6862
6863                let mut end;
6864                let mut buffer_end;
6865                let has_trailing_newline;
6866                let transform_end = self.diff_transforms.end();
6867                if transform_end.excerpt_dimension < self.excerpts.end() {
6868                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
6869                    end = transform_end.output_dimension.0;
6870                    buffer_end = buffer_context_start;
6871                    buffer_end += overshoot;
6872                    has_trailing_newline = false;
6873                } else {
6874                    let overshoot =
6875                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6876                    end = self.diff_transforms.start().output_dimension.0;
6877                    end += overshoot;
6878                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6879                    has_trailing_newline = excerpt.has_trailing_newline;
6880                };
6881
6882                let diff_hunk_status = inserted_hunk_info.map(|info| {
6883                    if info.is_logically_deleted {
6884                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6885                    } else {
6886                        DiffHunkStatus::added(info.hunk_secondary_status)
6887                    }
6888                });
6889
6890                Some(MultiBufferRegion {
6891                    buffer,
6892                    excerpt,
6893                    has_trailing_newline,
6894                    is_main_buffer: true,
6895                    diff_hunk_status,
6896                    buffer_range: buffer_start..buffer_end,
6897                    range: start..end,
6898                })
6899            }
6900        }
6901    }
6902
6903    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
6904        let excerpt = self.excerpts.item()?;
6905        match self.diff_transforms.item()? {
6906            &DiffTransform::DeletedHunk { .. } => {
6907                let start = self.diff_transforms.start().output_dimension.0;
6908                let end = self.diff_transforms.end().output_dimension.0;
6909                Some((excerpt, start..end))
6910            }
6911            DiffTransform::BufferContent { .. } => {
6912                let mut start = self.diff_transforms.start().output_dimension.0;
6913                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6914                    let overshoot =
6915                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6916                    start += overshoot;
6917                }
6918
6919                let mut end;
6920                let transform_end = self.diff_transforms.end();
6921                if transform_end.excerpt_dimension < self.excerpts.end() {
6922                    end = transform_end.output_dimension.0;
6923                } else {
6924                    let overshoot =
6925                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6926                    end = self.diff_transforms.start().output_dimension.0;
6927                    end += overshoot;
6928                };
6929
6930                Some((excerpt, start..end))
6931            }
6932        }
6933    }
6934
6935    fn excerpt(&self) -> Option<&'a Excerpt> {
6936        self.excerpts.item()
6937    }
6938}
6939
6940impl Excerpt {
6941    fn new(
6942        path_key: PathKey,
6943        path_key_index: PathKeyIndex,
6944        buffer_snapshot: &BufferSnapshot,
6945        range: ExcerptRange<text::Anchor>,
6946        has_trailing_newline: bool,
6947    ) -> Self {
6948        Excerpt {
6949            path_key,
6950            path_key_index,
6951            buffer_id: buffer_snapshot.remote_id(),
6952            max_buffer_row: range.context.end.to_point(&buffer_snapshot).row,
6953            text_summary: buffer_snapshot.text_summary_for_range::<TextSummary, _>(
6954                range.context.to_offset(&buffer_snapshot),
6955            ),
6956            range,
6957            has_trailing_newline,
6958        }
6959    }
6960
6961    fn buffer_snapshot<'a>(&self, snapshot: &'a MultiBufferSnapshot) -> &'a BufferSnapshot {
6962        &snapshot
6963            .buffers
6964            .get(&self.buffer_id)
6965            .expect("buffer snapshot not found for excerpt")
6966            .buffer_snapshot
6967    }
6968
6969    fn buffer(&self, multibuffer: &MultiBuffer) -> Entity<Buffer> {
6970        multibuffer
6971            .buffer(self.buffer_id)
6972            .expect("buffer entity not found for excerpt")
6973    }
6974
6975    fn info(&self) -> ExcerptInfo {
6976        ExcerptInfo {
6977            path_key_index: self.path_key_index,
6978            buffer_id: self.buffer_id,
6979            range: self.range.clone(),
6980        }
6981    }
6982
6983    fn chunks_in_range<'a>(
6984        &'a self,
6985        range: Range<usize>,
6986        language_aware: bool,
6987        snapshot: &'a MultiBufferSnapshot,
6988    ) -> ExcerptChunks<'a> {
6989        let buffer = self.buffer_snapshot(snapshot);
6990        let content_start = self.range.context.start.to_offset(buffer);
6991        let chunks_start = content_start + range.start;
6992        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6993
6994        let has_footer = self.has_trailing_newline
6995            && range.start <= self.text_summary.len
6996            && range.end > self.text_summary.len;
6997
6998        let content_chunks = buffer.chunks(chunks_start..chunks_end, language_aware);
6999
7000        ExcerptChunks {
7001            content_chunks,
7002            has_footer,
7003            end: self.end_anchor(),
7004        }
7005    }
7006
7007    fn seek_chunks(
7008        &self,
7009        excerpt_chunks: &mut ExcerptChunks,
7010        range: Range<usize>,
7011        snapshot: &MultiBufferSnapshot,
7012    ) {
7013        let buffer = self.buffer_snapshot(snapshot);
7014        let content_start = self.range.context.start.to_offset(buffer);
7015        let chunks_start = content_start + range.start;
7016        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7017        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7018        excerpt_chunks.has_footer = self.has_trailing_newline
7019            && range.start <= self.text_summary.len
7020            && range.end > self.text_summary.len;
7021    }
7022
7023    fn clip_anchor(
7024        &self,
7025        text_anchor: text::Anchor,
7026        snapshot: &MultiBufferSnapshot,
7027    ) -> text::Anchor {
7028        let buffer = self.buffer_snapshot(snapshot);
7029        if text_anchor.cmp(&self.range.context.start, buffer).is_lt() {
7030            self.range.context.start
7031        } else if text_anchor.cmp(&self.range.context.end, buffer).is_gt() {
7032            self.range.context.end
7033        } else {
7034            text_anchor
7035        }
7036    }
7037
7038    pub(crate) fn contains(&self, anchor: &ExcerptAnchor, snapshot: &MultiBufferSnapshot) -> bool {
7039        self.path_key_index == anchor.path
7040            && self.buffer_id == anchor.buffer_id
7041            && self
7042                .range
7043                .contains(&anchor.text_anchor(), self.buffer_snapshot(snapshot))
7044    }
7045
7046    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7047    fn buffer_start_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7048        BufferOffset(
7049            self.range
7050                .context
7051                .start
7052                .to_offset(self.buffer_snapshot(snapshot)),
7053        )
7054    }
7055
7056    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7057    fn buffer_end_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7058        self.buffer_start_offset(snapshot) + self.text_summary.len
7059    }
7060
7061    fn start_anchor(&self) -> ExcerptAnchor {
7062        todo!()
7063    }
7064
7065    fn end_anchor(&self) -> ExcerptAnchor {
7066        todo!()
7067    }
7068}
7069
7070impl PartialEq for Excerpt {
7071    fn eq(&self, other: &Self) -> bool {
7072        self.path_key_index == other.path_key_index
7073            && self.buffer_id == other.buffer_id
7074            && self.range.context == other.range.context
7075    }
7076}
7077
7078impl<'a> MultiBufferExcerpt<'a> {
7079    pub fn buffer_id(&self) -> BufferId {
7080        self.excerpt.buffer_id
7081    }
7082
7083    pub fn start_anchor(&self) -> Anchor {
7084        Anchor::in_buffer(
7085            self.excerpt.path_key_index,
7086            self.excerpt.range.context.start,
7087        )
7088    }
7089
7090    pub fn end_anchor(&self) -> Anchor {
7091        Anchor::in_buffer(self.excerpt.path_key_index, self.excerpt.range.context.end)
7092    }
7093
7094    pub fn buffer<'b>(&self, snapshot: &'b MultiBufferSnapshot) -> &'b BufferSnapshot {
7095        self.excerpt.buffer_snapshot(snapshot)
7096    }
7097
7098    pub fn buffer_range(&self, snapshot: &'a MultiBufferSnapshot) -> Range<BufferOffset> {
7099        self.buffer_offset
7100            ..BufferOffset(
7101                self.excerpt
7102                    .range
7103                    .context
7104                    .end
7105                    .to_offset(&self.excerpt.buffer_snapshot(snapshot).text),
7106            )
7107    }
7108
7109    pub fn start_offset(&self) -> MultiBufferOffset {
7110        self.offset
7111    }
7112
7113    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7114    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7115        self.map_range_to_buffer(offset..offset).start
7116    }
7117
7118    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7119    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7120        self.diff_transforms
7121            .seek(&OutputDimension(range.start), Bias::Right);
7122        let start = self.map_offset_to_buffer_internal(range.start);
7123        let end = if range.end > range.start {
7124            self.diff_transforms
7125                .seek_forward(&OutputDimension(range.end), Bias::Right);
7126            self.map_offset_to_buffer_internal(range.end)
7127        } else {
7128            start
7129        };
7130        start..end
7131    }
7132
7133    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7134        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7135        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7136            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7137        };
7138        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7139        self.buffer_offset + offset_in_excerpt
7140    }
7141
7142    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7143    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7144        self.map_range_from_buffer(buffer_offset..buffer_offset)
7145            .start
7146    }
7147
7148    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7149    pub fn map_range_from_buffer(
7150        &mut self,
7151        buffer_range: Range<BufferOffset>,
7152    ) -> Range<MultiBufferOffset> {
7153        if buffer_range.start < self.buffer_offset {
7154            log::warn!(
7155                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7156            );
7157            return self.offset..self.offset;
7158        }
7159        let overshoot = buffer_range.start - self.buffer_offset;
7160        let excerpt_offset = self.excerpt_offset + overshoot;
7161        let excerpt_seek_dim = excerpt_offset;
7162        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7163        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7164            log::warn!(
7165                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7166            );
7167            return self.offset..self.offset;
7168        }
7169        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7170        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7171
7172        let end = if buffer_range.start < buffer_range.end {
7173            let overshoot = buffer_range.end - self.buffer_offset;
7174            let excerpt_offset = self.excerpt_offset + overshoot;
7175            let excerpt_seek_dim = excerpt_offset;
7176            self.diff_transforms
7177                .seek_forward(&excerpt_seek_dim, Bias::Right);
7178            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7179            // todo(lw): Clamp end to the excerpt boundaries
7180            self.diff_transforms.start().output_dimension.0 + overshoot
7181        } else {
7182            start
7183        };
7184
7185        start..end
7186    }
7187
7188    /// Returns true if the entirety of the given range is in the buffer's excerpt
7189    pub fn contains_buffer_range(
7190        &self,
7191        range: Range<BufferOffset>,
7192        snapshot: &MultiBufferSnapshot,
7193    ) -> bool {
7194        range.start >= self.excerpt.buffer_start_offset(snapshot)
7195            && range.end <= self.excerpt.buffer_end_offset(snapshot)
7196    }
7197
7198    /// Returns true if any part of the given range is in the buffer's excerpt
7199    pub fn contains_partial_buffer_range(
7200        &self,
7201        range: Range<BufferOffset>,
7202        snapshot: &MultiBufferSnapshot,
7203    ) -> bool {
7204        range.start <= self.excerpt.buffer_end_offset(snapshot)
7205            && range.end >= self.excerpt.buffer_start_offset(snapshot)
7206    }
7207
7208    pub fn max_buffer_row(&self) -> u32 {
7209        self.excerpt.max_buffer_row
7210    }
7211}
7212
7213impl fmt::Debug for Excerpt {
7214    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7215        f.debug_struct("Excerpt")
7216            .field("path_key", &self.path_key)
7217            .field("range", &self.range)
7218            .field("text_summary", &self.text_summary)
7219            .field("has_trailing_newline", &self.has_trailing_newline)
7220            .finish()
7221    }
7222}
7223
7224impl sum_tree::Item for Excerpt {
7225    type Summary = ExcerptSummary;
7226
7227    fn summary(&self, _cx: ()) -> Self::Summary {
7228        let mut text = self.text_summary;
7229        if self.has_trailing_newline {
7230            text += TextSummary::from("\n");
7231        }
7232        ExcerptSummary {
7233            path_key: self.path_key.clone(),
7234            max_anchor: self.range.context.end,
7235            widest_line_number: self.max_buffer_row,
7236            text: text.into(),
7237            count: 1,
7238        }
7239    }
7240}
7241
7242impl DiffTransform {
7243    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7244        match self {
7245            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7246            DiffTransform::BufferContent {
7247                inserted_hunk_info, ..
7248            } => *inserted_hunk_info,
7249        }
7250    }
7251}
7252
7253impl sum_tree::Item for DiffTransform {
7254    type Summary = DiffTransformSummary;
7255
7256    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7257        match self {
7258            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7259                input: *summary,
7260                output: *summary,
7261            },
7262            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7263                input: MBTextSummary::default(),
7264                output: summary.into(),
7265            },
7266        }
7267    }
7268}
7269
7270impl DiffTransformSummary {
7271    fn excerpt_len(&self) -> ExcerptOffset {
7272        ExcerptDimension(self.input.len)
7273    }
7274}
7275
7276impl sum_tree::ContextLessSummary for DiffTransformSummary {
7277    fn zero() -> Self {
7278        DiffTransformSummary {
7279            input: MBTextSummary::default(),
7280            output: MBTextSummary::default(),
7281        }
7282    }
7283
7284    fn add_summary(&mut self, other: &Self) {
7285        self.input += other.input;
7286        self.output += other.output;
7287    }
7288}
7289
7290impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7291    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7292        PathKey::min()
7293    }
7294
7295    fn add_summary(
7296        &mut self,
7297        summary: &'_ ExcerptSummary,
7298        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7299    ) {
7300        *self = summary.path_key.clone();
7301    }
7302}
7303
7304impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7305    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7306        MultiBufferOffset::ZERO
7307    }
7308
7309    fn add_summary(
7310        &mut self,
7311        summary: &'_ ExcerptSummary,
7312        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7313    ) {
7314        *self += summary.text.len
7315    }
7316}
7317
7318impl sum_tree::ContextLessSummary for ExcerptSummary {
7319    fn zero() -> Self {
7320        Self::min()
7321    }
7322
7323    fn add_summary(&mut self, summary: &Self) {
7324        debug_assert!(
7325            summary.path_key >= self.path_key,
7326            "Path keys must be in ascending order: {:?} > {:?}",
7327            summary.path_key,
7328            self.path_key
7329        );
7330
7331        self.path_key = summary.path_key.clone();
7332        self.max_anchor = summary.max_anchor;
7333        self.text += summary.text;
7334        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7335        self.count += summary.count;
7336    }
7337}
7338
7339impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7340    fn cmp(
7341        &self,
7342        cursor_location: &ExcerptSummary,
7343        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7344    ) -> cmp::Ordering {
7345        match self {
7346            AnchorSeekTarget::Min => Ordering::Less,
7347            AnchorSeekTarget::Max => Ordering::Greater,
7348            AnchorSeekTarget::Excerpt {
7349                path_key,
7350                anchor,
7351                snapshot,
7352            } => {
7353                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7354                if path_comparison.is_ne() {
7355                    path_comparison
7356                } else if let Some(snapshot) = snapshot {
7357                    // todo!() think more about this..
7358                    // the goal is that if you seek to buffer_id 1 (path key a)
7359                    // and you find that path key a now belongs to buffer_id 2,
7360                    // we'll seek past buffer_id 2.
7361                    if let Some(buffer_id) = cursor_location.max_anchor.buffer_id
7362                        && buffer_id != snapshot.remote_id()
7363                    {
7364                        Ordering::Greater
7365                    } else {
7366                        anchor
7367                            .text_anchor()
7368                            .cmp(&cursor_location.max_anchor, snapshot)
7369                    }
7370                } else {
7371                    // shouldn't happen because we expect this buffer not to have any excerpts
7372                    // (otherwise snapshot would have been Some)
7373                    Ordering::Equal
7374                }
7375            }
7376        }
7377    }
7378}
7379
7380impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7381    fn cmp(
7382        &self,
7383        cursor_location: &ExcerptSummary,
7384        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7385    ) -> cmp::Ordering {
7386        Ord::cmp(self, &cursor_location.path_key)
7387    }
7388}
7389
7390impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7391where
7392    MBD: MultiBufferDimension + Default,
7393{
7394    fn zero(_: ()) -> Self {
7395        ExcerptDimension(MBD::default())
7396    }
7397
7398    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7399        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7400    }
7401}
7402
7403#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7404struct OutputDimension<T>(T);
7405
7406impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7407    fn eq(&self, other: &T) -> bool {
7408        self.0 == *other
7409    }
7410}
7411
7412impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7413    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7414        self.0.partial_cmp(other)
7415    }
7416}
7417
7418impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7419where
7420    T: ops::Sub<U, Output = R>,
7421{
7422    type Output = R;
7423
7424    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7425        self.0 - other.0
7426    }
7427}
7428
7429impl<R, T, U> ops::Add<U> for OutputDimension<T>
7430where
7431    T: ops::Add<U, Output = R>,
7432{
7433    type Output = OutputDimension<R>;
7434
7435    fn add(self, other: U) -> Self::Output {
7436        OutputDimension(self.0 + other)
7437    }
7438}
7439
7440impl<T, U> AddAssign<U> for OutputDimension<T>
7441where
7442    T: AddAssign<U>,
7443{
7444    fn add_assign(&mut self, other: U) {
7445        self.0 += other;
7446    }
7447}
7448
7449impl<T, U> SubAssign<U> for OutputDimension<T>
7450where
7451    T: SubAssign<U>,
7452{
7453    fn sub_assign(&mut self, other: U) {
7454        self.0 -= other;
7455    }
7456}
7457
7458#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7459struct ExcerptDimension<T>(T);
7460
7461impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7462    fn eq(&self, other: &T) -> bool {
7463        self.0 == *other
7464    }
7465}
7466
7467impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7468    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7469        self.0.partial_cmp(other)
7470    }
7471}
7472
7473impl ExcerptOffset {
7474    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7475        self.0.saturating_sub(other.0)
7476    }
7477}
7478
7479impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7480where
7481    T: ops::Sub<U, Output = R>,
7482{
7483    type Output = R;
7484
7485    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7486        self.0 - other.0
7487    }
7488}
7489
7490impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7491where
7492    T: ops::Add<U, Output = R>,
7493{
7494    type Output = ExcerptDimension<R>;
7495
7496    fn add(self, other: U) -> Self::Output {
7497        ExcerptDimension(self.0 + other)
7498    }
7499}
7500
7501impl<T, U> AddAssign<U> for ExcerptDimension<T>
7502where
7503    T: AddAssign<U>,
7504{
7505    fn add_assign(&mut self, other: U) {
7506        self.0 += other;
7507    }
7508}
7509
7510impl<T, U> SubAssign<U> for ExcerptDimension<T>
7511where
7512    T: SubAssign<U>,
7513{
7514    fn sub_assign(&mut self, other: U) {
7515        self.0 -= other;
7516    }
7517}
7518
7519impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7520    fn zero(_: ()) -> Self {
7521        MultiBufferOffset::ZERO
7522    }
7523
7524    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7525        *self += summary.output.len;
7526    }
7527}
7528
7529impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7530    for ExcerptDimension<MBD>
7531where
7532    MBD: MultiBufferDimension + Ord,
7533{
7534    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7535        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7536    }
7537}
7538
7539impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7540    for ExcerptDimension<MBD>
7541where
7542    MBD: MultiBufferDimension + Ord,
7543{
7544    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7545        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7546    }
7547}
7548
7549impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7550    for ExcerptDimension<MBD>
7551{
7552    fn zero(_: ()) -> Self {
7553        ExcerptDimension(MBD::default())
7554    }
7555
7556    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7557        self.0.add_mb_text_summary(&summary.input)
7558    }
7559}
7560
7561impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7562    for OutputDimension<MBD>
7563where
7564    MBD: MultiBufferDimension + Ord,
7565{
7566    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7567        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7568    }
7569}
7570
7571impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7572    for OutputDimension<MBD>
7573{
7574    fn zero(_: ()) -> Self {
7575        OutputDimension(MBD::default())
7576    }
7577
7578    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7579        self.0.add_mb_text_summary(&summary.output)
7580    }
7581}
7582
7583impl MultiBufferRows<'_> {
7584    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7585        self.point = Point::new(row, 0);
7586        self.cursor.seek(&self.point);
7587    }
7588}
7589
7590impl Iterator for MultiBufferRows<'_> {
7591    type Item = RowInfo;
7592
7593    fn next(&mut self) -> Option<Self::Item> {
7594        if self.is_empty && self.point.row == 0 {
7595            self.point += Point::new(1, 0);
7596            return Some(RowInfo {
7597                buffer_id: None,
7598                buffer_row: Some(0),
7599                multibuffer_row: Some(MultiBufferRow(0)),
7600                diff_status: None,
7601                expand_info: None,
7602                wrapped_buffer_row: None,
7603            });
7604        }
7605
7606        let mut region = self.cursor.region()?.clone();
7607        while self.point >= region.range.end {
7608            self.cursor.next();
7609            if let Some(next_region) = self.cursor.region() {
7610                region = next_region.clone();
7611            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7612                let multibuffer_row = MultiBufferRow(self.point.row);
7613                let last_excerpt = self
7614                    .cursor
7615                    .excerpts
7616                    .item()
7617                    .or(self.cursor.excerpts.prev_item())?;
7618                let buffer_snapshot = last_excerpt.buffer_snapshot(self.cursor.snapshot);
7619                let last_row = last_excerpt.range.context.end.to_point(buffer_snapshot).row;
7620
7621                let first_row = last_excerpt
7622                    .range
7623                    .context
7624                    .start
7625                    .to_point(buffer_snapshot)
7626                    .row;
7627
7628                let expand_info = if self.is_singleton {
7629                    None
7630                } else {
7631                    let needs_expand_up = first_row == last_row
7632                        && last_row > 0
7633                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7634                    let needs_expand_down = last_row < buffer_snapshot.max_point().row;
7635
7636                    if needs_expand_up && needs_expand_down {
7637                        Some(ExpandExcerptDirection::UpAndDown)
7638                    } else if needs_expand_up {
7639                        Some(ExpandExcerptDirection::Up)
7640                    } else if needs_expand_down {
7641                        Some(ExpandExcerptDirection::Down)
7642                    } else {
7643                        None
7644                    }
7645                    .map(|direction| ExpandInfo {
7646                        direction,
7647                        excerpt_range: last_excerpt.range.context.clone(),
7648                    })
7649                };
7650                self.point += Point::new(1, 0);
7651                return Some(RowInfo {
7652                    buffer_id: Some(last_excerpt.buffer_id),
7653                    buffer_row: Some(last_row),
7654                    multibuffer_row: Some(multibuffer_row),
7655                    diff_status: None,
7656                    wrapped_buffer_row: None,
7657                    expand_info,
7658                });
7659            } else {
7660                return None;
7661            };
7662        }
7663
7664        let overshoot = self.point - region.range.start;
7665        let buffer_point = region.buffer_range.start + overshoot;
7666        let expand_info = if self.is_singleton {
7667            None
7668        } else {
7669            let needs_expand_up = self.point.row == region.range.start.row
7670                && self.cursor.is_at_start_of_excerpt()
7671                && buffer_point.row > 0;
7672            let needs_expand_down = (region.excerpt.has_trailing_newline
7673                && self.point.row + 1 == region.range.end.row
7674                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7675                && self.cursor.is_at_end_of_excerpt()
7676                && buffer_point.row < region.buffer.max_point().row;
7677
7678            if needs_expand_up && needs_expand_down {
7679                Some(ExpandExcerptDirection::UpAndDown)
7680            } else if needs_expand_up {
7681                Some(ExpandExcerptDirection::Up)
7682            } else if needs_expand_down {
7683                Some(ExpandExcerptDirection::Down)
7684            } else {
7685                None
7686            }
7687            .map(|direction| ExpandInfo {
7688                direction,
7689                excerpt_range: region.excerpt.range.context.clone(),
7690            })
7691        };
7692
7693        let result = Some(RowInfo {
7694            buffer_id: Some(region.buffer.remote_id()),
7695            buffer_row: Some(buffer_point.row),
7696            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7697            diff_status: region
7698                .diff_hunk_status
7699                .filter(|_| self.point < region.range.end),
7700            expand_info,
7701            wrapped_buffer_row: None,
7702        });
7703        self.point += Point::new(1, 0);
7704        result
7705    }
7706}
7707
7708impl<'a> MultiBufferChunks<'a> {
7709    pub fn offset(&self) -> MultiBufferOffset {
7710        self.range.start
7711    }
7712
7713    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7714        self.diff_transforms.seek(&range.end, Bias::Right);
7715        let mut excerpt_end = self.diff_transforms.start().1;
7716        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7717            let overshoot = range.end - self.diff_transforms.start().0;
7718            excerpt_end += overshoot;
7719        }
7720
7721        self.diff_transforms.seek(&range.start, Bias::Right);
7722        let mut excerpt_start = self.diff_transforms.start().1;
7723        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7724            let overshoot = range.start - self.diff_transforms.start().0;
7725            excerpt_start += overshoot;
7726        }
7727
7728        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7729        self.buffer_chunk.take();
7730        self.range = range;
7731    }
7732
7733    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7734        self.excerpt_offset_range = new_range.clone();
7735        self.excerpts.seek(&new_range.start, Bias::Right);
7736        if let Some(excerpt) = self.excerpts.item() {
7737            let excerpt_start = *self.excerpts.start();
7738            if let Some(excerpt_chunks) = self
7739                .excerpt_chunks
7740                .as_mut()
7741                .filter(|chunks| excerpt.end_anchor() == chunks.end)
7742            {
7743                excerpt.seek_chunks(
7744                    excerpt_chunks,
7745                    (self.excerpt_offset_range.start - excerpt_start)
7746                        ..(self.excerpt_offset_range.end - excerpt_start),
7747                    self.snapshot,
7748                );
7749            } else {
7750                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7751                    (self.excerpt_offset_range.start - excerpt_start)
7752                        ..(self.excerpt_offset_range.end - excerpt_start),
7753                    self.language_aware,
7754                    self.snapshot,
7755                ));
7756            }
7757        } else {
7758            self.excerpt_chunks = None;
7759        }
7760    }
7761
7762    #[ztracing::instrument(skip_all)]
7763    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7764        loop {
7765            if self.excerpt_offset_range.is_empty() {
7766                return None;
7767            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7768                self.excerpt_offset_range.start += chunk.text.len();
7769                return Some(chunk);
7770            } else {
7771                self.excerpts.next();
7772                let excerpt = self.excerpts.item()?;
7773                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7774                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7775                    self.language_aware,
7776                    self.snapshot,
7777                ));
7778            }
7779        }
7780    }
7781}
7782
7783impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7784    type Item = &'a str;
7785
7786    fn next(&mut self) -> Option<Self::Item> {
7787        let mut region = self.cursor.region()?;
7788        if self.offset == region.range.start {
7789            self.cursor.prev();
7790            region = self.cursor.region()?;
7791            let start_overshoot = self.start.saturating_sub(region.range.start);
7792            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7793                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7794            ));
7795        }
7796
7797        if self.offset == region.range.end && region.has_trailing_newline {
7798            self.offset -= 1;
7799            Some("\n")
7800        } else {
7801            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7802            self.offset -= chunk.len();
7803            Some(chunk)
7804        }
7805    }
7806}
7807
7808impl<'a> Iterator for MultiBufferChunks<'a> {
7809    type Item = Chunk<'a>;
7810
7811    #[ztracing::instrument(skip_all)]
7812    fn next(&mut self) -> Option<Chunk<'a>> {
7813        if self.range.start >= self.range.end {
7814            return None;
7815        }
7816        if self.range.start == self.diff_transforms.end().0 {
7817            self.diff_transforms.next();
7818        }
7819
7820        let diff_transform_start = self.diff_transforms.start().0;
7821        let diff_transform_end = self.diff_transforms.end().0;
7822        debug_assert!(
7823            self.range.start < diff_transform_end,
7824            "{:?} < {:?} of ({1:?}..{2:?})",
7825            self.range.start,
7826            diff_transform_end,
7827            diff_transform_start
7828        );
7829
7830        let diff_transform = self.diff_transforms.item()?;
7831        match diff_transform {
7832            DiffTransform::BufferContent { .. } => {
7833                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7834                    chunk
7835                } else {
7836                    let chunk = self.next_excerpt_chunk().unwrap();
7837                    self.buffer_chunk.insert(chunk)
7838                };
7839
7840                let chunk_end = self.range.start + chunk.text.len();
7841                let diff_transform_end = diff_transform_end.min(self.range.end);
7842
7843                if diff_transform_end < chunk_end {
7844                    let split_idx = diff_transform_end - self.range.start;
7845                    let (before, after) = chunk.text.split_at(split_idx);
7846                    self.range.start = diff_transform_end;
7847                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7848                    let chars = chunk.chars & mask;
7849                    let tabs = chunk.tabs & mask;
7850                    let newlines = chunk.newlines & mask;
7851
7852                    chunk.text = after;
7853                    chunk.chars = chunk.chars >> split_idx;
7854                    chunk.tabs = chunk.tabs >> split_idx;
7855                    chunk.newlines = chunk.newlines >> split_idx;
7856
7857                    Some(Chunk {
7858                        text: before,
7859                        chars,
7860                        tabs,
7861                        newlines,
7862                        ..chunk.clone()
7863                    })
7864                } else {
7865                    self.range.start = chunk_end;
7866                    self.buffer_chunk.take()
7867                }
7868            }
7869            DiffTransform::DeletedHunk {
7870                buffer_id,
7871                base_text_byte_range,
7872                has_trailing_newline,
7873                ..
7874            } => {
7875                let base_text_start =
7876                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7877                let base_text_end =
7878                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7879                let base_text_end = base_text_end.min(base_text_byte_range.end);
7880
7881                let mut chunks = if let Some((_, mut chunks)) = self
7882                    .diff_base_chunks
7883                    .take()
7884                    .filter(|(id, _)| id == buffer_id)
7885                {
7886                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7887                    {
7888                        chunks.seek(base_text_start..base_text_end);
7889                    }
7890                    chunks
7891                } else {
7892                    let base_buffer = &self.snapshot.diffs.get(buffer_id)?.base_text();
7893                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7894                };
7895
7896                let chunk = if let Some(chunk) = chunks.next() {
7897                    self.range.start += chunk.text.len();
7898                    self.diff_base_chunks = Some((*buffer_id, chunks));
7899                    chunk
7900                } else {
7901                    debug_assert!(has_trailing_newline);
7902                    self.range.start += "\n".len();
7903                    Chunk {
7904                        text: "\n",
7905                        chars: 1u128,
7906                        newlines: 1u128,
7907                        ..Default::default()
7908                    }
7909                };
7910                Some(chunk)
7911            }
7912        }
7913    }
7914}
7915
7916impl MultiBufferBytes<'_> {
7917    fn consume(&mut self, len: usize) {
7918        self.range.start += len;
7919        self.chunk = &self.chunk[len..];
7920
7921        if !self.range.is_empty() && self.chunk.is_empty() {
7922            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7923                self.chunk = chunk;
7924            } else if self.has_trailing_newline {
7925                self.has_trailing_newline = false;
7926                self.chunk = b"\n";
7927            } else {
7928                self.cursor.next();
7929                if let Some(region) = self.cursor.region() {
7930                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7931                        region.buffer_range.start
7932                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7933                                .min(region.buffer_range.end),
7934                    );
7935                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7936                    self.excerpt_bytes = Some(excerpt_bytes);
7937                    self.has_trailing_newline =
7938                        region.has_trailing_newline && self.range.end >= region.range.end;
7939                    if self.chunk.is_empty() && self.has_trailing_newline {
7940                        self.has_trailing_newline = false;
7941                        self.chunk = b"\n";
7942                    }
7943                }
7944            }
7945        }
7946    }
7947}
7948
7949impl<'a> Iterator for MultiBufferBytes<'a> {
7950    type Item = &'a [u8];
7951
7952    fn next(&mut self) -> Option<Self::Item> {
7953        let chunk = self.chunk;
7954        if chunk.is_empty() {
7955            None
7956        } else {
7957            self.consume(chunk.len());
7958            Some(chunk)
7959        }
7960    }
7961}
7962
7963impl io::Read for MultiBufferBytes<'_> {
7964    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7965        let len = cmp::min(buf.len(), self.chunk.len());
7966        buf[..len].copy_from_slice(&self.chunk[..len]);
7967        if len > 0 {
7968            self.consume(len);
7969        }
7970        Ok(len)
7971    }
7972}
7973
7974impl io::Read for ReversedMultiBufferBytes<'_> {
7975    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7976        let len = cmp::min(buf.len(), self.chunk.len());
7977        buf[..len].copy_from_slice(&self.chunk[..len]);
7978        buf[..len].reverse();
7979        if len > 0 {
7980            self.range.end -= len;
7981            self.chunk = &self.chunk[..self.chunk.len() - len];
7982            if !self.range.is_empty()
7983                && self.chunk.is_empty()
7984                && let Some(chunk) = self.chunks.next()
7985            {
7986                self.chunk = chunk.as_bytes();
7987            }
7988        }
7989        Ok(len)
7990    }
7991}
7992
7993impl<'a> Iterator for ExcerptChunks<'a> {
7994    type Item = Chunk<'a>;
7995
7996    fn next(&mut self) -> Option<Self::Item> {
7997        if let Some(chunk) = self.content_chunks.next() {
7998            return Some(chunk);
7999        }
8000
8001        if self.has_footer {
8002            let text = "\n";
8003            let chars = 0b1;
8004            let newlines = 0b1;
8005            self.has_footer = false;
8006            return Some(Chunk {
8007                text,
8008                chars,
8009                newlines,
8010                ..Default::default()
8011            });
8012        }
8013
8014        None
8015    }
8016}
8017
8018impl ToOffset for Point {
8019    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8020        snapshot.point_to_offset(*self)
8021    }
8022    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8023        snapshot.point_to_offset_utf16(*self)
8024    }
8025}
8026
8027impl ToOffset for MultiBufferOffset {
8028    #[track_caller]
8029    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8030        assert!(
8031            *self <= snapshot.len(),
8032            "offset {} is greater than the snapshot.len() {}",
8033            self.0,
8034            snapshot.len().0,
8035        );
8036        *self
8037    }
8038    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8039        snapshot.offset_to_offset_utf16(*self)
8040    }
8041}
8042
8043impl ToOffset for MultiBufferOffsetUtf16 {
8044    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8045        snapshot.offset_utf16_to_offset(*self)
8046    }
8047
8048    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8049        *self
8050    }
8051}
8052
8053impl ToOffset for PointUtf16 {
8054    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8055        snapshot.point_utf16_to_offset(*self)
8056    }
8057    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8058        snapshot.point_utf16_to_offset_utf16(*self)
8059    }
8060}
8061
8062impl ToPoint for MultiBufferOffset {
8063    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8064        snapshot.offset_to_point(*self)
8065    }
8066    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8067        snapshot.offset_to_point_utf16(*self)
8068    }
8069}
8070
8071impl ToPoint for Point {
8072    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8073        *self
8074    }
8075    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8076        snapshot.point_to_point_utf16(*self)
8077    }
8078}
8079
8080impl ToPoint for PointUtf16 {
8081    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8082        snapshot.point_utf16_to_point(*self)
8083    }
8084    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8085        *self
8086    }
8087}
8088
8089#[cfg(debug_assertions)]
8090pub mod debug {
8091    use super::*;
8092
8093    pub trait ToMultiBufferDebugRanges {
8094        fn to_multi_buffer_debug_ranges(
8095            &self,
8096            snapshot: &MultiBufferSnapshot,
8097        ) -> Vec<Range<MultiBufferOffset>>;
8098    }
8099
8100    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8101        fn to_multi_buffer_debug_ranges(
8102            &self,
8103            snapshot: &MultiBufferSnapshot,
8104        ) -> Vec<Range<MultiBufferOffset>> {
8105            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8106        }
8107    }
8108
8109    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8110        fn to_multi_buffer_debug_ranges(
8111            &self,
8112            snapshot: &MultiBufferSnapshot,
8113        ) -> Vec<Range<MultiBufferOffset>> {
8114            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8115                .to_multi_buffer_debug_ranges(snapshot)
8116        }
8117    }
8118
8119    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8120        fn to_multi_buffer_debug_ranges(
8121            &self,
8122            snapshot: &MultiBufferSnapshot,
8123        ) -> Vec<Range<MultiBufferOffset>> {
8124            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8125        }
8126    }
8127
8128    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8129        fn to_multi_buffer_debug_ranges(
8130            &self,
8131            snapshot: &MultiBufferSnapshot,
8132        ) -> Vec<Range<MultiBufferOffset>> {
8133            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8134        }
8135    }
8136
8137    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8138        fn to_multi_buffer_debug_ranges(
8139            &self,
8140            snapshot: &MultiBufferSnapshot,
8141        ) -> Vec<Range<MultiBufferOffset>> {
8142            self.iter()
8143                .map(|item| {
8144                    let offset = item.to_offset(snapshot);
8145                    offset..offset
8146                })
8147                .collect()
8148        }
8149    }
8150
8151    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8152        fn to_multi_buffer_debug_ranges(
8153            &self,
8154            snapshot: &MultiBufferSnapshot,
8155        ) -> Vec<Range<MultiBufferOffset>> {
8156            self.iter()
8157                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8158                .collect()
8159        }
8160    }
8161}