multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use crate::anchor::ExcerptAnchor;
   8
   9use self::transaction::History;
  10
  11pub use anchor::{Anchor, AnchorRangeExt};
  12
  13use anchor::AnchorSeekTarget;
  14use anyhow::{Result, anyhow};
  15use buffer_diff::{
  16    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  17    DiffHunkStatus, DiffHunkStatusKind,
  18};
  19use clock::ReplicaId;
  20use collections::{BTreeMap, Bound, HashMap, HashSet};
  21use gpui::{App, Context, Entity, EventEmitter};
  22use itertools::Itertools;
  23use language::{
  24    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  25    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  26    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  27    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  28    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  29    language_settings::{LanguageSettings, language_settings},
  30};
  31
  32#[cfg(any(test, feature = "test-support"))]
  33use gpui::AppContext as _;
  34
  35use rope::DimensionPair;
  36use smallvec::SmallVec;
  37use smol::future::yield_now;
  38use std::{
  39    any::type_name,
  40    borrow::Cow,
  41    cell::{Cell, OnceCell, Ref, RefCell},
  42    cmp::{self, Ordering},
  43    fmt,
  44    future::Future,
  45    io,
  46    iter::{self, FromIterator},
  47    mem,
  48    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  49    rc::Rc,
  50    str,
  51    sync::{Arc, OnceLock},
  52    time::Duration,
  53};
  54use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  55use text::{
  56    BufferId, Edit, LineIndent, TextSummary,
  57    locator::Locator,
  58    subscription::{Subscription, Topic},
  59};
  60use theme::SyntaxTheme;
  61use ztracing::instrument;
  62
  63pub use self::path_key::PathKey;
  64
  65pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  66
  67pub fn excerpt_context_lines(cx: &App) -> u32 {
  68    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  69}
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from buffer IDs to their diff states
  81    diffs: HashMap<BufferId, DiffState>,
  82    subscriptions: Topic<MultiBufferOffset>,
  83    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  84    singleton: bool,
  85    /// The history of the multi-buffer.
  86    history: History,
  87    /// The explicit title of the multi-buffer.
  88    /// If `None`, it will be derived from the underlying path or content.
  89    title: Option<String>,
  90    /// The writing capability of the multi-buffer.
  91    capability: Capability,
  92    buffer_changed_since_sync: Rc<Cell<bool>>,
  93}
  94
  95#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
  96pub struct PathKeyIndex(u64);
  97
  98pub struct ExcerptInfo {
  99    path_key_index: PathKeyIndex,
 100    buffer_id: BufferId,
 101    range: ExcerptRange<text::Anchor>,
 102}
 103
 104#[derive(Clone, Debug, PartialEq, Eq)]
 105pub enum Event {
 106    BufferUpdated {
 107        buffer: Entity<Buffer>,
 108        path_key: PathKey,
 109        ranges: Vec<Range<text::Anchor>>,
 110    },
 111    BuffersRemoved {
 112        removed_buffer_ids: Vec<BufferId>,
 113    },
 114    BuffersEdited {
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    path_key_index: PathKeyIndex,
 140    /// The buffer ID that this hunk belongs to.
 141    pub buffer_id: BufferId,
 142    /// The range of the underlying buffer that this hunk corresponds to.
 143    pub buffer_range: Range<text::Anchor>,
 144    /// The range within the buffer's diff base that this hunk corresponds to.
 145    pub diff_base_byte_range: Range<BufferOffset>,
 146    /// The status of this hunk (added/modified/deleted and secondary status).
 147    pub status: DiffHunkStatus,
 148    /// The word diffs for this hunk.
 149    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 150}
 151
 152impl MultiBufferDiffHunk {
 153    pub fn status(&self) -> DiffHunkStatus {
 154        self.status
 155    }
 156
 157    pub fn is_created_file(&self) -> bool {
 158        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 159            && self.buffer_range.start.is_min()
 160            && self.buffer_range.end.is_max()
 161    }
 162
 163    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 164        let start = Anchor::in_buffer(self.path_key_index, self.buffer_range.start);
 165        let end = Anchor::in_buffer(self.path_key_index, self.buffer_range.end);
 166        start..end
 167    }
 168}
 169
 170pub type MultiBufferPoint = Point;
 171/// ExcerptOffset is offset into the non-deleted text of the multibuffer
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173/// ExcerptOffset is based on the non-deleted text of the multibuffer
 174type ExcerptPoint = ExcerptDimension<Point>;
 175
 176#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 177#[serde(transparent)]
 178pub struct MultiBufferRow(pub u32);
 179
 180impl MultiBufferRow {
 181    pub const MIN: Self = Self(0);
 182    pub const MAX: Self = Self(u32::MAX);
 183}
 184
 185impl ops::Add<usize> for MultiBufferRow {
 186    type Output = Self;
 187
 188    fn add(self, rhs: usize) -> Self::Output {
 189        MultiBufferRow(self.0 + rhs as u32)
 190    }
 191}
 192
 193pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 194    type TextDimension: TextDimension;
 195    fn from_summary(summary: &MBTextSummary) -> Self;
 196
 197    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 198
 199    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 200}
 201
 202// todo(lw): MultiBufferPoint
 203impl MultiBufferDimension for Point {
 204    type TextDimension = Point;
 205    fn from_summary(summary: &MBTextSummary) -> Self {
 206        summary.lines
 207    }
 208
 209    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 210        *self += *other;
 211    }
 212
 213    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 214        *self += summary.lines;
 215    }
 216}
 217
 218// todo(lw): MultiBufferPointUtf16
 219impl MultiBufferDimension for PointUtf16 {
 220    type TextDimension = PointUtf16;
 221    fn from_summary(summary: &MBTextSummary) -> Self {
 222        summary.lines_utf16()
 223    }
 224
 225    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 226        *self += *other;
 227    }
 228
 229    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 230        *self += summary.lines_utf16();
 231    }
 232}
 233
 234#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 235pub struct MultiBufferOffset(pub usize);
 236
 237impl fmt::Display for MultiBufferOffset {
 238    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 239        write!(f, "{}", self.0)
 240    }
 241}
 242
 243impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 244    type Sampler = MultiBufferOffsetUniformSampler;
 245}
 246
 247pub struct MultiBufferOffsetUniformSampler {
 248    sampler: rand::distr::uniform::UniformUsize,
 249}
 250
 251impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 252    type X = MultiBufferOffset;
 253
 254    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 255    where
 256        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 258    {
 259        let low = *low_b.borrow();
 260        let high = *high_b.borrow();
 261        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 262        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 263    }
 264
 265    #[inline] // if the range is constant, this helps LLVM to do the
 266    // calculations at compile-time.
 267    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 268    where
 269        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 271    {
 272        let low = *low_b.borrow();
 273        let high = *high_b.borrow();
 274        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 275        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 276    }
 277
 278    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 279        MultiBufferOffset(self.sampler.sample(rng))
 280    }
 281}
 282impl MultiBufferDimension for MultiBufferOffset {
 283    type TextDimension = usize;
 284    fn from_summary(summary: &MBTextSummary) -> Self {
 285        summary.len
 286    }
 287
 288    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 289        self.0 += *other;
 290    }
 291
 292    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 293        *self += summary.len;
 294    }
 295}
 296impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 297    type TextDimension = OffsetUtf16;
 298    fn from_summary(summary: &MBTextSummary) -> Self {
 299        MultiBufferOffsetUtf16(summary.len_utf16)
 300    }
 301
 302    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 303        self.0 += *other;
 304    }
 305
 306    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 307        self.0 += summary.len_utf16;
 308    }
 309}
 310
 311#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 312pub struct BufferOffset(pub usize);
 313
 314impl TextDimension for BufferOffset {
 315    fn from_text_summary(summary: &TextSummary) -> Self {
 316        BufferOffset(usize::from_text_summary(summary))
 317    }
 318    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 319        BufferOffset(usize::from_chunk(chunk))
 320    }
 321    fn add_assign(&mut self, other: &Self) {
 322        TextDimension::add_assign(&mut self.0, &other.0);
 323    }
 324}
 325impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 326    fn zero(cx: ()) -> Self {
 327        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 328    }
 329
 330    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 331        usize::add_summary(&mut self.0, summary, cx);
 332    }
 333}
 334
 335impl Sub for BufferOffset {
 336    type Output = usize;
 337
 338    fn sub(self, other: BufferOffset) -> Self::Output {
 339        self.0 - other.0
 340    }
 341}
 342
 343impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 344    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 345        self.0 += other.key;
 346    }
 347}
 348
 349impl language::ToPoint for BufferOffset {
 350    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 351        self.0.to_point(snapshot)
 352    }
 353}
 354
 355impl language::ToPointUtf16 for BufferOffset {
 356    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 357        self.0.to_point_utf16(snapshot)
 358    }
 359}
 360
 361impl language::ToOffset for BufferOffset {
 362    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 363        self.0.to_offset(snapshot)
 364    }
 365}
 366
 367impl language::ToOffsetUtf16 for BufferOffset {
 368    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 369        self.0.to_offset_utf16(snapshot)
 370    }
 371}
 372
 373#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 374pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 375
 376impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 377    type Output = MultiBufferOffsetUtf16;
 378
 379    fn add(self, rhs: usize) -> Self::Output {
 380        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 381    }
 382}
 383
 384impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 385    type Output = Self;
 386
 387    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 388        MultiBufferOffsetUtf16(self.0 + rhs)
 389    }
 390}
 391
 392impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 393    fn add_assign(&mut self, rhs: OffsetUtf16) {
 394        self.0 += rhs;
 395    }
 396}
 397
 398impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 399    fn add_assign(&mut self, rhs: usize) {
 400        self.0.0 += rhs;
 401    }
 402}
 403
 404impl Sub for MultiBufferOffsetUtf16 {
 405    type Output = OffsetUtf16;
 406
 407    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 408        self.0 - other.0
 409    }
 410}
 411
 412impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 413    type Output = MultiBufferOffsetUtf16;
 414
 415    fn sub(self, other: OffsetUtf16) -> Self::Output {
 416        MultiBufferOffsetUtf16(self.0 - other)
 417    }
 418}
 419
 420#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 421pub struct BufferOffsetUtf16(pub OffsetUtf16);
 422
 423impl MultiBufferOffset {
 424    const ZERO: Self = Self(0);
 425    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 426        self.0.saturating_sub(other.0)
 427    }
 428    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 429        MultiBufferOffset(self.0.saturating_sub(other))
 430    }
 431}
 432
 433impl ops::Sub for MultiBufferOffset {
 434    type Output = usize;
 435
 436    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 437        self.0 - other.0
 438    }
 439}
 440
 441impl ops::Sub<usize> for MultiBufferOffset {
 442    type Output = Self;
 443
 444    fn sub(self, other: usize) -> Self::Output {
 445        MultiBufferOffset(self.0 - other)
 446    }
 447}
 448
 449impl ops::SubAssign<usize> for MultiBufferOffset {
 450    fn sub_assign(&mut self, other: usize) {
 451        self.0 -= other;
 452    }
 453}
 454
 455impl ops::Add<usize> for BufferOffset {
 456    type Output = Self;
 457
 458    fn add(self, rhs: usize) -> Self::Output {
 459        BufferOffset(self.0 + rhs)
 460    }
 461}
 462
 463impl ops::AddAssign<usize> for BufferOffset {
 464    fn add_assign(&mut self, other: usize) {
 465        self.0 += other;
 466    }
 467}
 468
 469impl ops::Add<usize> for MultiBufferOffset {
 470    type Output = Self;
 471
 472    fn add(self, rhs: usize) -> Self::Output {
 473        MultiBufferOffset(self.0 + rhs)
 474    }
 475}
 476
 477impl ops::AddAssign<usize> for MultiBufferOffset {
 478    fn add_assign(&mut self, other: usize) {
 479        self.0 += other;
 480    }
 481}
 482
 483impl ops::Add<isize> for MultiBufferOffset {
 484    type Output = Self;
 485
 486    fn add(self, rhs: isize) -> Self::Output {
 487        MultiBufferOffset((self.0 as isize + rhs) as usize)
 488    }
 489}
 490
 491impl ops::Add for MultiBufferOffset {
 492    type Output = Self;
 493
 494    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 495        MultiBufferOffset(self.0 + rhs.0)
 496    }
 497}
 498
 499impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 500    fn add_assign(&mut self, other: MultiBufferOffset) {
 501        self.0 += other.0;
 502    }
 503}
 504
 505pub trait ToOffset: 'static + fmt::Debug {
 506    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 507    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 508}
 509
 510pub trait ToPoint: 'static + fmt::Debug {
 511    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 512    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 513}
 514
 515struct BufferState {
 516    buffer: Entity<Buffer>,
 517    last_version: RefCell<clock::Global>,
 518    last_non_text_state_update_count: Cell<usize>,
 519    _subscriptions: [gpui::Subscription; 2],
 520}
 521
 522struct DiffState {
 523    diff: Entity<BufferDiff>,
 524    main_buffer: Option<Entity<language::Buffer>>,
 525    _subscription: gpui::Subscription,
 526}
 527
 528impl DiffState {
 529    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 530        DiffStateSnapshot {
 531            diff: self.diff.read(cx).snapshot(cx),
 532            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 533        }
 534    }
 535}
 536
 537#[derive(Clone)]
 538struct DiffStateSnapshot {
 539    diff: BufferDiffSnapshot,
 540    main_buffer: Option<language::BufferSnapshot>,
 541}
 542
 543impl std::ops::Deref for DiffStateSnapshot {
 544    type Target = BufferDiffSnapshot;
 545
 546    fn deref(&self) -> &Self::Target {
 547        &self.diff
 548    }
 549}
 550
 551impl DiffState {
 552    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 553        DiffState {
 554            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 555                BufferDiffEvent::DiffChanged(DiffChanged {
 556                    changed_range,
 557                    base_text_changed_range: _,
 558                    extended_range,
 559                }) => {
 560                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 561                    let range = if use_extended {
 562                        extended_range.clone()
 563                    } else {
 564                        changed_range.clone()
 565                    };
 566                    if let Some(range) = range {
 567                        this.buffer_diff_changed(diff, range, cx)
 568                    }
 569                    cx.emit(Event::BufferDiffChanged);
 570                }
 571                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 572                _ => {}
 573            }),
 574            diff,
 575            main_buffer: None,
 576        }
 577    }
 578
 579    fn new_inverted(
 580        diff: Entity<BufferDiff>,
 581        main_buffer: Entity<language::Buffer>,
 582        cx: &mut Context<MultiBuffer>,
 583    ) -> Self {
 584        let weak_main_buffer = main_buffer.downgrade();
 585        DiffState {
 586            _subscription: cx.subscribe(&diff, {
 587                move |this, diff, event, cx| {
 588                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 589                        return;
 590                    };
 591                    match event {
 592                        BufferDiffEvent::DiffChanged(DiffChanged {
 593                            changed_range: _,
 594                            base_text_changed_range,
 595                            extended_range: _,
 596                        }) => {
 597                            this.inverted_buffer_diff_changed(
 598                                diff,
 599                                main_buffer,
 600                                base_text_changed_range.clone(),
 601                                cx,
 602                            );
 603                            cx.emit(Event::BufferDiffChanged);
 604                        }
 605                        BufferDiffEvent::LanguageChanged => {
 606                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 607                        }
 608                        _ => {}
 609                    }
 610                }
 611            }),
 612            diff,
 613            main_buffer: Some(main_buffer),
 614        }
 615    }
 616}
 617
 618/// The contents of a [`MultiBuffer`] at a single point in time.
 619#[derive(Clone, Default)]
 620pub struct MultiBufferSnapshot {
 621    excerpts: SumTree<Excerpt>,
 622    path_keys_by_buffer: TreeMap<BufferId, PathKey>,
 623    path_keys_by_index: TreeMap<PathKeyIndex, PathKey>,
 624    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 625    diff_transforms: SumTree<DiffTransform>,
 626    non_text_state_update_count: usize,
 627    edit_count: usize,
 628    is_dirty: bool,
 629    has_deleted_file: bool,
 630    has_conflict: bool,
 631    has_inverted_diff: bool,
 632    singleton: bool,
 633    trailing_excerpt_update_count: usize,
 634    all_diff_hunks_expanded: bool,
 635    show_deleted_hunks: bool,
 636    use_extended_diff_range: bool,
 637    show_headers: bool,
 638}
 639
 640#[derive(Debug, Clone)]
 641enum DiffTransform {
 642    BufferContent {
 643        summary: MBTextSummary,
 644        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 645    },
 646    DeletedHunk {
 647        summary: TextSummary,
 648        buffer_id: BufferId,
 649        hunk_info: DiffTransformHunkInfo,
 650        base_text_byte_range: Range<usize>,
 651        has_trailing_newline: bool,
 652    },
 653}
 654
 655#[derive(Clone, Copy, Debug)]
 656struct DiffTransformHunkInfo {
 657    buffer_id: BufferId,
 658    hunk_start_anchor: text::Anchor,
 659    hunk_secondary_status: DiffHunkSecondaryStatus,
 660    is_logically_deleted: bool,
 661    excerpt_end: ExcerptAnchor,
 662}
 663
 664impl Eq for DiffTransformHunkInfo {}
 665
 666impl PartialEq for DiffTransformHunkInfo {
 667    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 668        self.buffer_id == other.buffer_id && self.hunk_start_anchor == other.hunk_start_anchor
 669    }
 670}
 671
 672impl std::hash::Hash for DiffTransformHunkInfo {
 673    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 674        self.buffer_id.hash(state);
 675        self.hunk_start_anchor.hash(state);
 676    }
 677}
 678
 679#[derive(Clone)]
 680pub struct ExcerptBoundaryInfo {
 681    pub buffer: Arc<BufferSnapshot>,
 682    pub buffer_id: BufferId,
 683    pub range: ExcerptRange<text::Anchor>,
 684    pub end_row: MultiBufferRow,
 685}
 686
 687impl std::fmt::Debug for ExcerptBoundaryInfo {
 688    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 689        f.debug_struct(type_name::<Self>())
 690            .field("buffer_id", &self.buffer_id)
 691            .field("path", &self.buffer.file().map(|f| f.path()))
 692            .field("range", &self.range)
 693            .finish()
 694    }
 695}
 696
 697/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 698#[derive(Debug)]
 699pub struct ExcerptBoundary {
 700    pub prev: Option<ExcerptBoundaryInfo>,
 701    pub next: ExcerptBoundaryInfo,
 702    /// The row in the `MultiBuffer` where the boundary is located
 703    pub row: MultiBufferRow,
 704}
 705
 706impl ExcerptBoundary {
 707    pub fn starts_new_buffer(&self) -> bool {
 708        match (self.prev.as_ref(), &self.next) {
 709            (None, _) => true,
 710            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 711        }
 712    }
 713}
 714
 715#[derive(Clone, Debug, PartialEq, Eq)]
 716pub struct ExpandInfo {
 717    pub direction: ExpandExcerptDirection,
 718    pub excerpt_range: Range<text::Anchor>,
 719}
 720
 721#[derive(Clone, Debug, Default, PartialEq, Eq)]
 722pub struct RowInfo {
 723    pub buffer_id: Option<BufferId>,
 724    pub buffer_row: Option<u32>,
 725    pub multibuffer_row: Option<MultiBufferRow>,
 726    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 727    pub expand_info: Option<ExpandInfo>,
 728    pub wrapped_buffer_row: Option<u32>,
 729}
 730
 731/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 732#[derive(Clone)]
 733pub(crate) struct Excerpt {
 734    /// The location of the excerpt in the [`MultiBuffer`]
 735    pub(crate) path_key: PathKey,
 736    pub(crate) path_key_index: PathKeyIndex,
 737    /// A snapshot of the buffer being excerpted
 738    pub(crate) buffer: Arc<BufferSnapshot>,
 739    /// The range of the buffer to be shown in the excerpt
 740    pub(crate) range: ExcerptRange<text::Anchor>,
 741
 742    /// The last row in the excerpted slice of the buffer
 743    pub(crate) max_buffer_row: BufferRow,
 744    /// A summary of the text in the excerpt
 745    pub(crate) text_summary: TextSummary,
 746    pub(crate) has_trailing_newline: bool,
 747}
 748
 749/// A public view into an `Excerpt` in a [`MultiBuffer`].
 750///
 751/// Contains methods for getting the [`Buffer`] of the excerpt,
 752/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 753#[derive(Clone)]
 754pub struct MultiBufferExcerpt<'a> {
 755    excerpt: &'a Excerpt,
 756    diff_transforms:
 757        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 758    /// The offset in the multibuffer considering diff transforms.
 759    offset: MultiBufferOffset,
 760    /// The offset in the multibuffer without diff transforms.
 761    excerpt_offset: ExcerptOffset,
 762    buffer_offset: BufferOffset,
 763}
 764
 765/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 766/// These ranges are relative to the buffer itself
 767#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 768pub struct ExcerptRange<T> {
 769    /// The full range of text to be shown in the excerpt.
 770    pub context: Range<T>,
 771    /// The primary range of text to be highlighted in the excerpt.
 772    /// In a multi-buffer search, this would be the text that matched the search
 773    pub primary: Range<T>,
 774}
 775
 776impl<T: Clone> ExcerptRange<T> {
 777    pub fn new(context: Range<T>) -> Self {
 778        Self {
 779            context: context.clone(),
 780            primary: context,
 781        }
 782    }
 783}
 784
 785impl ExcerptRange<text::Anchor> {
 786    pub fn contains(&self, t: &text::Anchor, snapshot: &BufferSnapshot) -> bool {
 787        self.context.start.cmp(t, snapshot).is_le() && self.context.end.cmp(t, snapshot).is_ge()
 788    }
 789}
 790
 791#[derive(Clone, Debug)]
 792pub struct ExcerptSummary {
 793    path_key: PathKey,
 794    max_anchor: text::Anchor,
 795    widest_line_number: u32,
 796    text: MBTextSummary,
 797    count: usize,
 798}
 799
 800impl ExcerptSummary {
 801    pub fn min() -> Self {
 802        ExcerptSummary {
 803            path_key: PathKey::min(),
 804            max_anchor: text::Anchor::MIN,
 805            widest_line_number: 0,
 806            text: MBTextSummary::default(),
 807            count: 0,
 808        }
 809    }
 810
 811    pub fn len(&self) -> ExcerptOffset {
 812        ExcerptDimension(self.text.len)
 813    }
 814}
 815
 816#[derive(Debug, Clone)]
 817pub struct DiffTransformSummary {
 818    input: MBTextSummary,
 819    output: MBTextSummary,
 820}
 821
 822/// Summary of a string of text.
 823#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 824pub struct MBTextSummary {
 825    /// Length in bytes.
 826    pub len: MultiBufferOffset,
 827    /// Length in UTF-8.
 828    pub chars: usize,
 829    /// Length in UTF-16 code units
 830    pub len_utf16: OffsetUtf16,
 831    /// A point representing the number of lines and the length of the last line.
 832    ///
 833    /// In other words, it marks the point after the last byte in the text, (if
 834    /// EOF was a character, this would be its position).
 835    pub lines: Point,
 836    /// How many `char`s are in the first line
 837    pub first_line_chars: u32,
 838    /// How many `char`s are in the last line
 839    pub last_line_chars: u32,
 840    /// How many UTF-16 code units are in the last line
 841    pub last_line_len_utf16: u32,
 842    /// The row idx of the longest row
 843    pub longest_row: u32,
 844    /// How many `char`s are in the longest row
 845    pub longest_row_chars: u32,
 846}
 847
 848impl From<TextSummary> for MBTextSummary {
 849    fn from(summary: TextSummary) -> Self {
 850        MBTextSummary {
 851            len: MultiBufferOffset(summary.len),
 852            chars: summary.chars,
 853            len_utf16: summary.len_utf16,
 854            lines: summary.lines,
 855            first_line_chars: summary.first_line_chars,
 856            last_line_chars: summary.last_line_chars,
 857            last_line_len_utf16: summary.last_line_len_utf16,
 858            longest_row: summary.longest_row,
 859            longest_row_chars: summary.longest_row_chars,
 860        }
 861    }
 862}
 863
 864impl From<MBTextSummary> for TextSummary {
 865    fn from(summary: MBTextSummary) -> Self {
 866        TextSummary {
 867            len: summary.len.0,
 868            chars: summary.chars,
 869            len_utf16: summary.len_utf16,
 870            lines: summary.lines,
 871            first_line_chars: summary.first_line_chars,
 872            last_line_chars: summary.last_line_chars,
 873            last_line_len_utf16: summary.last_line_len_utf16,
 874            longest_row: summary.longest_row,
 875            longest_row_chars: summary.longest_row_chars,
 876        }
 877    }
 878}
 879
 880impl From<&str> for MBTextSummary {
 881    fn from(text: &str) -> Self {
 882        MBTextSummary::from(TextSummary::from(text))
 883    }
 884}
 885
 886impl MultiBufferDimension for MBTextSummary {
 887    type TextDimension = TextSummary;
 888
 889    fn from_summary(summary: &MBTextSummary) -> Self {
 890        *summary
 891    }
 892
 893    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 894        *self += *summary;
 895    }
 896
 897    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 898        *self += *summary;
 899    }
 900}
 901
 902impl AddAssign for MBTextSummary {
 903    fn add_assign(&mut self, other: MBTextSummary) {
 904        let joined_chars = self.last_line_chars + other.first_line_chars;
 905        if joined_chars > self.longest_row_chars {
 906            self.longest_row = self.lines.row;
 907            self.longest_row_chars = joined_chars;
 908        }
 909        if other.longest_row_chars > self.longest_row_chars {
 910            self.longest_row = self.lines.row + other.longest_row;
 911            self.longest_row_chars = other.longest_row_chars;
 912        }
 913
 914        if self.lines.row == 0 {
 915            self.first_line_chars += other.first_line_chars;
 916        }
 917
 918        if other.lines.row == 0 {
 919            self.last_line_chars += other.first_line_chars;
 920            self.last_line_len_utf16 += other.last_line_len_utf16;
 921        } else {
 922            self.last_line_chars = other.last_line_chars;
 923            self.last_line_len_utf16 = other.last_line_len_utf16;
 924        }
 925
 926        self.chars += other.chars;
 927        self.len += other.len;
 928        self.len_utf16 += other.len_utf16;
 929        self.lines += other.lines;
 930    }
 931}
 932
 933impl AddAssign<TextSummary> for MBTextSummary {
 934    fn add_assign(&mut self, other: TextSummary) {
 935        *self += MBTextSummary::from(other);
 936    }
 937}
 938
 939impl MBTextSummary {
 940    pub fn lines_utf16(&self) -> PointUtf16 {
 941        PointUtf16 {
 942            row: self.lines.row,
 943            column: self.last_line_len_utf16,
 944        }
 945    }
 946}
 947
 948impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 949where
 950    K: MultiBufferDimension,
 951    V: MultiBufferDimension,
 952{
 953    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 954
 955    fn from_summary(summary: &MBTextSummary) -> Self {
 956        Self {
 957            key: K::from_summary(summary),
 958            value: Some(V::from_summary(summary)),
 959        }
 960    }
 961
 962    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 963        self.key.add_text_dim(&summary.key);
 964        if let Some(value) = &mut self.value {
 965            if let Some(other_value) = summary.value.as_ref() {
 966                value.add_text_dim(other_value);
 967            }
 968        }
 969    }
 970
 971    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 972        self.key.add_mb_text_summary(summary);
 973        if let Some(value) = &mut self.value {
 974            value.add_mb_text_summary(summary);
 975        }
 976    }
 977}
 978
 979#[derive(Clone)]
 980pub struct MultiBufferRows<'a> {
 981    point: Point,
 982    is_empty: bool,
 983    is_singleton: bool,
 984    cursor: MultiBufferCursor<'a, Point, Point>,
 985}
 986
 987pub struct MultiBufferChunks<'a> {
 988    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 989    diff_transforms:
 990        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 991    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 992    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 993    buffer_chunk: Option<Chunk<'a>>,
 994    range: Range<MultiBufferOffset>,
 995    excerpt_offset_range: Range<ExcerptOffset>,
 996    excerpt_chunks: Option<ExcerptChunks<'a>>,
 997    language_aware: bool,
 998}
 999
1000pub struct ReversedMultiBufferChunks<'a> {
1001    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1002    current_chunks: Option<rope::Chunks<'a>>,
1003    start: MultiBufferOffset,
1004    offset: MultiBufferOffset,
1005}
1006
1007pub struct MultiBufferBytes<'a> {
1008    range: Range<MultiBufferOffset>,
1009    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1010    excerpt_bytes: Option<text::Bytes<'a>>,
1011    has_trailing_newline: bool,
1012    chunk: &'a [u8],
1013}
1014
1015pub struct ReversedMultiBufferBytes<'a> {
1016    range: Range<MultiBufferOffset>,
1017    chunks: ReversedMultiBufferChunks<'a>,
1018    chunk: &'a [u8],
1019}
1020
1021#[derive(Clone)]
1022struct DiffTransforms<MBD> {
1023    output_dimension: OutputDimension<MBD>,
1024    excerpt_dimension: ExcerptDimension<MBD>,
1025}
1026
1027impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1028    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1029        Self {
1030            output_dimension: OutputDimension::zero(cx),
1031            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1032                cx,
1033            ),
1034        }
1035    }
1036
1037    fn add_summary(
1038        &mut self,
1039        summary: &'a DiffTransformSummary,
1040        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1041    ) {
1042        self.output_dimension.add_summary(summary, cx);
1043        self.excerpt_dimension.add_summary(summary, cx);
1044    }
1045}
1046
1047#[derive(Clone)]
1048struct MultiBufferCursor<'a, MBD, BD> {
1049    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1050    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1051    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1052    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1053}
1054
1055#[derive(Clone)]
1056struct MultiBufferRegion<'a, MBD, BD> {
1057    buffer: &'a BufferSnapshot,
1058    is_main_buffer: bool,
1059    diff_hunk_status: Option<DiffHunkStatus>,
1060    excerpt: &'a Excerpt,
1061    buffer_range: Range<BD>,
1062    range: Range<MBD>,
1063    has_trailing_newline: bool,
1064}
1065
1066struct ExcerptChunks<'a> {
1067    content_chunks: BufferChunks<'a>,
1068    end: ExcerptAnchor,
1069    has_footer: bool,
1070}
1071
1072#[derive(Debug)]
1073struct BufferEdit {
1074    range: Range<BufferOffset>,
1075    new_text: Arc<str>,
1076    is_insertion: bool,
1077    original_indent_column: Option<u32>,
1078}
1079
1080#[derive(Clone, Copy, Debug, PartialEq)]
1081enum DiffChangeKind {
1082    BufferEdited,
1083    DiffUpdated { base_changed: bool },
1084    ExpandOrCollapseHunks { expand: bool },
1085}
1086
1087#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1088pub enum ExpandExcerptDirection {
1089    Up,
1090    Down,
1091    UpAndDown,
1092}
1093
1094impl ExpandExcerptDirection {
1095    pub fn should_expand_up(&self) -> bool {
1096        match self {
1097            ExpandExcerptDirection::Up => true,
1098            ExpandExcerptDirection::Down => false,
1099            ExpandExcerptDirection::UpAndDown => true,
1100        }
1101    }
1102
1103    pub fn should_expand_down(&self) -> bool {
1104        match self {
1105            ExpandExcerptDirection::Up => false,
1106            ExpandExcerptDirection::Down => true,
1107            ExpandExcerptDirection::UpAndDown => true,
1108        }
1109    }
1110}
1111
1112#[derive(Clone, Debug, PartialEq)]
1113pub struct IndentGuide {
1114    pub buffer_id: BufferId,
1115    pub start_row: MultiBufferRow,
1116    pub end_row: MultiBufferRow,
1117    pub depth: u32,
1118    pub tab_size: u32,
1119    pub settings: IndentGuideSettings,
1120}
1121
1122impl IndentGuide {
1123    pub fn indent_level(&self) -> u32 {
1124        self.depth * self.tab_size
1125    }
1126}
1127
1128impl MultiBuffer {
1129    pub fn new(capability: Capability) -> Self {
1130        Self::new_(
1131            capability,
1132            MultiBufferSnapshot {
1133                show_headers: true,
1134                show_deleted_hunks: true,
1135                ..MultiBufferSnapshot::default()
1136            },
1137        )
1138    }
1139
1140    pub fn without_headers(capability: Capability) -> Self {
1141        Self::new_(
1142            capability,
1143            MultiBufferSnapshot {
1144                show_deleted_hunks: true,
1145                ..MultiBufferSnapshot::default()
1146            },
1147        )
1148    }
1149
1150    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1151        let mut this = Self::new_(
1152            buffer.read(cx).capability(),
1153            MultiBufferSnapshot {
1154                singleton: true,
1155                show_deleted_hunks: true,
1156                ..MultiBufferSnapshot::default()
1157            },
1158        );
1159        this.singleton = true;
1160        this.set_excerpts_for_path(
1161            PathKey::sorted(0),
1162            buffer.clone(),
1163            [Point::zero()..buffer.read(cx).max_point()],
1164            0,
1165            cx,
1166        );
1167        this
1168    }
1169
1170    #[inline]
1171    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1172        Self {
1173            snapshot: RefCell::new(snapshot),
1174            buffers: Default::default(),
1175            diffs: HashMap::default(),
1176            subscriptions: Topic::default(),
1177            singleton: false,
1178            capability,
1179            title: None,
1180            buffer_changed_since_sync: Default::default(),
1181            history: History::default(),
1182        }
1183    }
1184
1185    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1186        let mut buffers = BTreeMap::default();
1187        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1188        for (buffer_id, buffer_state) in self.buffers.iter() {
1189            buffer_state.buffer.update(new_cx, |buffer, _| {
1190                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1191            });
1192            buffers.insert(
1193                *buffer_id,
1194                BufferState {
1195                    buffer: buffer_state.buffer.clone(),
1196                    last_version: buffer_state.last_version.clone(),
1197                    last_non_text_state_update_count: buffer_state
1198                        .last_non_text_state_update_count
1199                        .clone(),
1200                    _subscriptions: [
1201                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1202                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1203                    ],
1204                },
1205            );
1206        }
1207        let mut diff_bases = HashMap::default();
1208        for (buffer_id, diff) in self.diffs.iter() {
1209            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1210        }
1211        Self {
1212            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1213            buffers,
1214            diffs: diff_bases,
1215            subscriptions: Default::default(),
1216            singleton: self.singleton,
1217            capability: self.capability,
1218            history: self.history.clone(),
1219            title: self.title.clone(),
1220            buffer_changed_since_sync,
1221        }
1222    }
1223
1224    pub fn set_group_interval(&mut self, group_interval: Duration) {
1225        self.history.set_group_interval(group_interval);
1226    }
1227
1228    pub fn with_title(mut self, title: String) -> Self {
1229        self.title = Some(title);
1230        self
1231    }
1232
1233    pub fn read_only(&self) -> bool {
1234        !self.capability.editable()
1235    }
1236
1237    pub fn capability(&self) -> Capability {
1238        self.capability
1239    }
1240
1241    /// Returns an up-to-date snapshot of the MultiBuffer.
1242    #[ztracing::instrument(skip_all)]
1243    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1244        self.sync(cx);
1245        self.snapshot.borrow().clone()
1246    }
1247
1248    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1249        self.sync(cx);
1250        self.snapshot.borrow()
1251    }
1252
1253    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1254        if self.singleton {
1255            Some(self.buffers.values().next().unwrap().buffer.clone())
1256        } else {
1257            None
1258        }
1259    }
1260
1261    pub fn is_singleton(&self) -> bool {
1262        self.singleton
1263    }
1264
1265    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1266        self.subscriptions.subscribe()
1267    }
1268
1269    pub fn is_dirty(&self, cx: &App) -> bool {
1270        self.read(cx).is_dirty()
1271    }
1272
1273    pub fn has_deleted_file(&self, cx: &App) -> bool {
1274        self.read(cx).has_deleted_file()
1275    }
1276
1277    pub fn has_conflict(&self, cx: &App) -> bool {
1278        self.read(cx).has_conflict()
1279    }
1280
1281    // The `is_empty` signature doesn't match what clippy expects
1282    #[allow(clippy::len_without_is_empty)]
1283    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1284        self.read(cx).len()
1285    }
1286
1287    pub fn is_empty(&self) -> bool {
1288        self.buffers.is_empty()
1289    }
1290
1291    pub fn edit<I, S, T>(
1292        &mut self,
1293        edits: I,
1294        autoindent_mode: Option<AutoindentMode>,
1295        cx: &mut Context<Self>,
1296    ) where
1297        I: IntoIterator<Item = (Range<S>, T)>,
1298        S: ToOffset,
1299        T: Into<Arc<str>>,
1300    {
1301        self.edit_internal(edits, autoindent_mode, true, cx);
1302    }
1303
1304    pub fn edit_non_coalesce<I, S, T>(
1305        &mut self,
1306        edits: I,
1307        autoindent_mode: Option<AutoindentMode>,
1308        cx: &mut Context<Self>,
1309    ) where
1310        I: IntoIterator<Item = (Range<S>, T)>,
1311        S: ToOffset,
1312        T: Into<Arc<str>>,
1313    {
1314        self.edit_internal(edits, autoindent_mode, false, cx);
1315    }
1316
1317    fn edit_internal<I, S, T>(
1318        &mut self,
1319        edits: I,
1320        autoindent_mode: Option<AutoindentMode>,
1321        coalesce_adjacent: bool,
1322        cx: &mut Context<Self>,
1323    ) where
1324        I: IntoIterator<Item = (Range<S>, T)>,
1325        S: ToOffset,
1326        T: Into<Arc<str>>,
1327    {
1328        if self.read_only() || self.buffers.is_empty() {
1329            return;
1330        }
1331        self.sync_mut(cx);
1332        let edits = edits
1333            .into_iter()
1334            .map(|(range, new_text)| {
1335                let mut range = range.start.to_offset(self.snapshot.get_mut())
1336                    ..range.end.to_offset(self.snapshot.get_mut());
1337                if range.start > range.end {
1338                    mem::swap(&mut range.start, &mut range.end);
1339                }
1340                (range, new_text.into())
1341            })
1342            .collect::<Vec<_>>();
1343
1344        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1345
1346        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1347        fn edit_internal(
1348            this: &mut MultiBuffer,
1349            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1350            mut autoindent_mode: Option<AutoindentMode>,
1351            coalesce_adjacent: bool,
1352            cx: &mut Context<MultiBuffer>,
1353        ) {
1354            let original_indent_columns = match &mut autoindent_mode {
1355                Some(AutoindentMode::Block {
1356                    original_indent_columns,
1357                }) => mem::take(original_indent_columns),
1358                _ => Default::default(),
1359            };
1360
1361            let buffer_edits = MultiBuffer::convert_edits_to_buffer_edits(
1362                edits,
1363                this.snapshot.get_mut(),
1364                &original_indent_columns,
1365            );
1366
1367            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1368            for (buffer_id, mut edits) in buffer_edits {
1369                buffer_ids.push(buffer_id);
1370                edits.sort_by_key(|edit| edit.range.start);
1371                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1372                    let mut edits = edits.into_iter().peekable();
1373                    let mut insertions = Vec::new();
1374                    let mut original_indent_columns = Vec::new();
1375                    let mut deletions = Vec::new();
1376                    let empty_str: Arc<str> = Arc::default();
1377                    while let Some(BufferEdit {
1378                        mut range,
1379                        mut new_text,
1380                        mut is_insertion,
1381                        original_indent_column,
1382                    }) = edits.next()
1383                    {
1384                        while let Some(BufferEdit {
1385                            range: next_range,
1386                            is_insertion: next_is_insertion,
1387                            new_text: next_new_text,
1388                            ..
1389                        }) = edits.peek()
1390                        {
1391                            let should_coalesce = if coalesce_adjacent {
1392                                range.end >= next_range.start
1393                            } else {
1394                                range.end > next_range.start
1395                            };
1396
1397                            if should_coalesce {
1398                                range.end = cmp::max(next_range.end, range.end);
1399                                is_insertion |= *next_is_insertion;
1400                                new_text = format!("{new_text}{next_new_text}").into();
1401                                edits.next();
1402                            } else {
1403                                break;
1404                            }
1405                        }
1406
1407                        if is_insertion {
1408                            original_indent_columns.push(original_indent_column);
1409                            insertions.push((
1410                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1411                                new_text.clone(),
1412                            ));
1413                        } else if !range.is_empty() {
1414                            deletions.push((
1415                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1416                                empty_str.clone(),
1417                            ));
1418                        }
1419                    }
1420
1421                    let deletion_autoindent_mode =
1422                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1423                            Some(AutoindentMode::Block {
1424                                original_indent_columns: Default::default(),
1425                            })
1426                        } else {
1427                            autoindent_mode.clone()
1428                        };
1429                    let insertion_autoindent_mode =
1430                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1431                            Some(AutoindentMode::Block {
1432                                original_indent_columns,
1433                            })
1434                        } else {
1435                            autoindent_mode.clone()
1436                        };
1437
1438                    if coalesce_adjacent {
1439                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1440                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1441                    } else {
1442                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1443                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1444                    }
1445                })
1446            }
1447
1448            cx.emit(Event::BuffersEdited { buffer_ids });
1449        }
1450    }
1451
1452    fn convert_edits_to_buffer_edits(
1453        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1454        snapshot: &MultiBufferSnapshot,
1455        original_indent_columns: &[Option<u32>],
1456    ) -> HashMap<BufferId, Vec<BufferEdit>> {
1457        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1458        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1459        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1460            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1461
1462            cursor.seek(&range.start);
1463            let mut start_region = cursor.region().expect("start offset out of bounds");
1464            if !start_region.is_main_buffer {
1465                cursor.next();
1466                if let Some(region) = cursor.region() {
1467                    start_region = region;
1468                } else {
1469                    continue;
1470                }
1471            }
1472
1473            if range.end < start_region.range.start {
1474                continue;
1475            }
1476
1477            let start_region = start_region.clone();
1478            if range.end > start_region.range.end {
1479                cursor.seek_forward(&range.end);
1480            }
1481            let mut end_region = cursor.region().expect("end offset out of bounds");
1482            if !end_region.is_main_buffer {
1483                cursor.prev();
1484                if let Some(region) = cursor.region() {
1485                    end_region = region;
1486                } else {
1487                    continue;
1488                }
1489            }
1490
1491            if range.start > end_region.range.end {
1492                continue;
1493            }
1494
1495            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1496            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1497            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1498                .min(start_region.buffer_range.end);
1499            let buffer_end =
1500                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1501
1502            if start_region.excerpt == end_region.excerpt {
1503                if start_region.buffer.capability == Capability::ReadWrite
1504                    && start_region.is_main_buffer
1505                {
1506                    buffer_edits
1507                        .entry(start_region.buffer.remote_id())
1508                        .or_default()
1509                        .push(BufferEdit {
1510                            range: buffer_start..buffer_end,
1511                            new_text,
1512                            is_insertion: true,
1513                            original_indent_column,
1514                        });
1515                }
1516            } else {
1517                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1518                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1519                if start_region.buffer.capability == Capability::ReadWrite
1520                    && start_region.is_main_buffer
1521                {
1522                    buffer_edits
1523                        .entry(start_region.buffer.remote_id())
1524                        .or_default()
1525                        .push(BufferEdit {
1526                            range: start_excerpt_range,
1527                            new_text: new_text.clone(),
1528                            is_insertion: true,
1529                            original_indent_column,
1530                        });
1531                }
1532                if end_region.buffer.capability == Capability::ReadWrite
1533                    && end_region.is_main_buffer
1534                {
1535                    buffer_edits
1536                        .entry(end_region.buffer.remote_id())
1537                        .or_default()
1538                        .push(BufferEdit {
1539                            range: end_excerpt_range,
1540                            new_text: new_text.clone(),
1541                            is_insertion: false,
1542                            original_indent_column,
1543                        });
1544                }
1545                let end_region_excerpt = end_region.excerpt.clone();
1546
1547                cursor.seek(&range.start);
1548                cursor.next_excerpt();
1549                while let Some(region) = cursor.region() {
1550                    if region.excerpt == &end_region_excerpt {
1551                        break;
1552                    }
1553                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1554                        buffer_edits
1555                            .entry(region.buffer.remote_id())
1556                            .or_default()
1557                            .push(BufferEdit {
1558                                range: region.buffer_range.clone(),
1559                                new_text: new_text.clone(),
1560                                is_insertion: false,
1561                                original_indent_column,
1562                            });
1563                    }
1564                    cursor.next_excerpt();
1565                }
1566            }
1567        }
1568        buffer_edits
1569    }
1570
1571    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1572    where
1573        I: IntoIterator<Item = Range<S>>,
1574        S: ToOffset,
1575    {
1576        if self.read_only() || self.buffers.is_empty() {
1577            return;
1578        }
1579        self.sync_mut(cx);
1580        let empty = Arc::<str>::from("");
1581        let edits = ranges
1582            .into_iter()
1583            .map(|range| {
1584                let mut range = range.start.to_offset(self.snapshot.get_mut())
1585                    ..range.end.to_offset(&self.snapshot.get_mut());
1586                if range.start > range.end {
1587                    mem::swap(&mut range.start, &mut range.end);
1588                }
1589                (range, empty.clone())
1590            })
1591            .collect::<Vec<_>>();
1592
1593        return autoindent_ranges_internal(self, edits, cx);
1594
1595        fn autoindent_ranges_internal(
1596            this: &mut MultiBuffer,
1597            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1598            cx: &mut Context<MultiBuffer>,
1599        ) {
1600            let buffer_edits =
1601                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1602
1603            let mut buffer_ids = Vec::new();
1604            for (buffer_id, mut edits) in buffer_edits {
1605                buffer_ids.push(buffer_id);
1606                edits.sort_unstable_by_key(|edit| edit.range.start);
1607
1608                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1609                for edit in edits {
1610                    if let Some(last_range) = ranges.last_mut()
1611                        && edit.range.start <= last_range.end
1612                    {
1613                        last_range.end = last_range.end.max(edit.range.end);
1614                        continue;
1615                    }
1616                    ranges.push(edit.range);
1617                }
1618
1619                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1620                    buffer.autoindent_ranges(ranges, cx);
1621                })
1622            }
1623
1624            cx.emit(Event::BuffersEdited { buffer_ids });
1625        }
1626    }
1627
1628    pub fn set_active_selections(
1629        &self,
1630        selections: &[Selection<Anchor>],
1631        line_mode: bool,
1632        cursor_shape: CursorShape,
1633        cx: &mut Context<Self>,
1634    ) {
1635        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1636            Default::default();
1637        let snapshot = self.read(cx);
1638        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(());
1639        for selection in selections {
1640            let start = selection.start.seek_target(&snapshot);
1641
1642            cursor.seek(&start, Bias::Left);
1643            while let Some(excerpt) = cursor.item() {
1644                // todo!() method?
1645                let excerpt_start =
1646                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.end);
1647                if excerpt_start.cmp(&selection.end, &snapshot).is_gt() {
1648                    break;
1649                }
1650                let start = text::Anchor::max(
1651                    &excerpt.range.context.start,
1652                    &selection
1653                        .start
1654                        .excerpt_anchor()
1655                        .map(|excerpt_anchor| excerpt_anchor.text_anchor())
1656                        .unwrap_or(text::Anchor::MIN),
1657                    &excerpt.buffer,
1658                )
1659                .clone();
1660                let end = text::Anchor::min(
1661                    &excerpt.range.context.end,
1662                    &selection
1663                        .end
1664                        .excerpt_anchor()
1665                        .map(|excerpt_anchor| excerpt_anchor.text_anchor())
1666                        .unwrap_or(text::Anchor::MAX),
1667                    &excerpt.buffer,
1668                )
1669                .clone();
1670                selections_by_buffer
1671                    .entry(excerpt.buffer.remote_id())
1672                    .or_default()
1673                    .push(Selection {
1674                        id: selection.id,
1675                        start,
1676                        end,
1677                        reversed: selection.reversed,
1678                        goal: selection.goal,
1679                    });
1680
1681                cursor.next();
1682            }
1683        }
1684
1685        for (buffer_id, buffer_state) in self.buffers.iter() {
1686            if !selections_by_buffer.contains_key(buffer_id) {
1687                buffer_state
1688                    .buffer
1689                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1690            }
1691        }
1692
1693        for (buffer_id, selections) in selections_by_buffer {
1694            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1695                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1696            });
1697        }
1698    }
1699
1700    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1701        for buffer in self.buffers.values() {
1702            buffer
1703                .buffer
1704                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1705        }
1706    }
1707
1708    #[instrument(skip_all)]
1709    fn merge_excerpt_ranges<'a>(
1710        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1711    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1712        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1713        let mut counts: Vec<usize> = Vec::new();
1714        for range in expanded_ranges {
1715            if let Some(last_range) = merged_ranges.last_mut() {
1716                assert!(
1717                    last_range.context.start <= range.context.start,
1718                    "ranges must be sorted: {last_range:?} <= {range:?}"
1719                );
1720                if last_range.context.end >= range.context.start
1721                    || last_range.context.end.row + 1 == range.context.start.row
1722                {
1723                    last_range.context.end = range.context.end.max(last_range.context.end);
1724                    *counts.last_mut().unwrap() += 1;
1725                    continue;
1726                }
1727            }
1728            merged_ranges.push(range.clone());
1729            counts.push(1);
1730        }
1731        (merged_ranges, counts)
1732    }
1733
1734    pub fn clear(&mut self, cx: &mut Context<Self>) {
1735        self.sync_mut(cx);
1736        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1737        let MultiBufferSnapshot {
1738            excerpts,
1739            diffs: _,
1740            diff_transforms: _,
1741            non_text_state_update_count: _,
1742            edit_count: _,
1743            is_dirty,
1744            has_deleted_file,
1745            has_conflict,
1746            has_inverted_diff,
1747            singleton: _,
1748            trailing_excerpt_update_count,
1749            all_diff_hunks_expanded: _,
1750            show_deleted_hunks: _,
1751            use_extended_diff_range: _,
1752            show_headers: _,
1753            path_keys_by_buffer: _,
1754            path_keys_by_index: _,
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        *trailing_excerpt_update_count += 1;
1760        *is_dirty = false;
1761        *has_deleted_file = false;
1762        *has_conflict = false;
1763        *has_inverted_diff = false;
1764
1765        let edits = Self::sync_diff_transforms(
1766            self.snapshot.get_mut(),
1767            vec![Edit {
1768                old: start..prev_len,
1769                new: start..start,
1770            }],
1771            DiffChangeKind::BufferEdited,
1772        );
1773        if !edits.is_empty() {
1774            self.subscriptions.publish(edits);
1775        }
1776        cx.emit(Event::Edited {
1777            edited_buffer: None,
1778        });
1779        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1780        cx.notify();
1781    }
1782
1783    #[ztracing::instrument(skip_all)]
1784    pub fn excerpts_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<ExcerptInfo> {
1785        let mut excerpts = Vec::new();
1786        let snapshot = self.read(cx);
1787        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id).cloned() else {
1788            return excerpts;
1789        };
1790
1791        let mut cursor = snapshot.excerpts.cursor::<PathKey>(());
1792        cursor.seek_forward(&path_key, Bias::Left);
1793
1794        while let Some(excerpt) = cursor.item()
1795            && excerpt.path_key == path_key
1796        {
1797            excerpts.push(excerpt.info());
1798            cursor.next()
1799        }
1800        excerpts
1801    }
1802
1803    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1804        let snapshot = self.read(cx);
1805        let mut excerpts = snapshot
1806            .excerpts
1807            .cursor::<Dimensions<PathKey, ExcerptPoint>>(());
1808        let mut diff_transforms = snapshot
1809            .diff_transforms
1810            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1811        diff_transforms.next();
1812        let mut result = Vec::new();
1813        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id) else {
1814            return result;
1815        };
1816
1817        while let Some(excerpt) = excerpts.item()
1818            && &excerpt.path_key == path_key
1819        {
1820            let excerpt_start = excerpts.start().1;
1821            let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1822
1823            diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1824            let overshoot = excerpt_start - diff_transforms.start().0;
1825            let start = diff_transforms.start().1 + overshoot;
1826
1827            diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1828            let overshoot = excerpt_end - diff_transforms.start().0;
1829            let end = diff_transforms.start().1 + overshoot;
1830
1831            result.push(start.0..end.0);
1832            excerpts.next()
1833        }
1834        result
1835    }
1836
1837    // todo!() this seems bogus
1838    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1839        self.snapshot
1840            .borrow()
1841            .excerpts
1842            .iter()
1843            .map(|entry| entry.buffer.remote_id())
1844            .collect()
1845    }
1846
1847    pub fn excerpt_containing(&self, position: impl ToOffset, cx: &App) -> Option<ExcerptInfo> {
1848        let snapshot = self.read(cx);
1849        let offset = position.to_offset(&snapshot);
1850
1851        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1852        cursor.seek(&offset);
1853        let excerpt = cursor.excerpt().or(snapshot.excerpts.last())?;
1854        Some(excerpt.info())
1855    }
1856
1857    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1858        let buffer_id = match anchor {
1859            Anchor::Min => self.snapshot(cx).excerpts.first()?.buffer.remote_id(),
1860            Anchor::Max => self.snapshot(cx).excerpts.last()?.buffer.remote_id(),
1861            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor.buffer_id,
1862        };
1863        self.buffer(buffer_id)
1864    }
1865
1866    // If point is at the end of the buffer, the last excerpt is returned
1867    pub fn point_to_buffer_offset<T: ToOffset>(
1868        &self,
1869        point: T,
1870        cx: &App,
1871    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1872        let snapshot = self.read(cx);
1873        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1874        Some((
1875            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1876            offset,
1877        ))
1878    }
1879
1880    // If point is at the end of the buffer, the last excerpt is returned
1881    pub fn point_to_buffer_point<T: ToPoint>(
1882        &self,
1883        point: T,
1884        cx: &App,
1885    ) -> Option<(Entity<Buffer>, Point)> {
1886        let snapshot = self.read(cx);
1887        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1888        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1889    }
1890
1891    pub fn buffer_point_to_anchor(
1892        &self,
1893        // todo(lw): We shouldn't need this?
1894        buffer: &Entity<Buffer>,
1895        point: Point,
1896        cx: &App,
1897    ) -> Option<Anchor> {
1898        let mut found = None;
1899        let snapshot = buffer.read(cx).snapshot();
1900        let text_anchor = snapshot.anchor_after(&point);
1901        for excerpt in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1902            if excerpt.range.contains(&text_anchor, &snapshot) {
1903                found = Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
1904                break;
1905            }
1906            if excerpt
1907                .range
1908                .context
1909                .start
1910                .cmp(&text_anchor, &snapshot)
1911                .is_gt()
1912            {
1913                found = Some(Anchor::in_buffer(
1914                    excerpt.path_key_index,
1915                    excerpt.range.context.start,
1916                ));
1917                break;
1918            }
1919            found = Some(Anchor::in_buffer(
1920                excerpt.path_key_index,
1921                excerpt.range.context.end,
1922            ));
1923        }
1924
1925        found
1926    }
1927
1928    pub fn buffer_anchor_to_anchor(
1929        &self,
1930        // todo(lw): We shouldn't need this?
1931        buffer: &Entity<Buffer>,
1932        anchor: text::Anchor,
1933        cx: &App,
1934    ) -> Option<Anchor> {
1935        let snapshot = buffer.read(cx).snapshot();
1936        for excerpt in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1937            if excerpt.range.contains(&anchor, &snapshot) {
1938                return Some(Anchor::in_buffer(excerpt.path_key_index, anchor));
1939            }
1940        }
1941
1942        None
1943    }
1944
1945    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1946        &self,
1947        anchors: Anchors,
1948        cx: &mut Context<Self>,
1949    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1950        let mut error = None;
1951        let mut futures = Vec::new();
1952        for anchor in anchors {
1953            if let Some(excerpt_anchor) = anchor.excerpt_anchor() {
1954                if let Some(buffer) = self.buffers.get(&excerpt_anchor.buffer_id) {
1955                    buffer.buffer.update(cx, |buffer, _| {
1956                        futures.push(buffer.wait_for_anchors([excerpt_anchor.text_anchor()]))
1957                    });
1958                } else {
1959                    error = Some(anyhow!(
1960                        "buffer {:?} is not part of this multi-buffer",
1961                        excerpt_anchor.buffer_id
1962                    ));
1963                    break;
1964                }
1965            }
1966        }
1967        async move {
1968            if let Some(error) = error {
1969                Err(error)?;
1970            }
1971            for future in futures {
1972                future.await?;
1973            }
1974            Ok(())
1975        }
1976    }
1977
1978    pub fn text_anchor_for_position<T: ToOffset>(
1979        &self,
1980        position: T,
1981        cx: &App,
1982    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1983        let snapshot = self.read(cx);
1984        let anchor = snapshot.anchor_before(position).excerpt_anchor()?;
1985        let buffer = self.buffers.get(&anchor.buffer_id)?.buffer.clone();
1986        Some((buffer, anchor.text_anchor()))
1987    }
1988
1989    fn on_buffer_event(
1990        &mut self,
1991        buffer: Entity<Buffer>,
1992        event: &language::BufferEvent,
1993        cx: &mut Context<Self>,
1994    ) {
1995        use language::BufferEvent;
1996        let buffer_id = buffer.read(cx).remote_id();
1997        cx.emit(match event {
1998            BufferEvent::Edited => Event::Edited {
1999                edited_buffer: Some(buffer),
2000            },
2001            BufferEvent::DirtyChanged => Event::DirtyChanged,
2002            BufferEvent::Saved => Event::Saved,
2003            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2004            BufferEvent::Reloaded => Event::Reloaded,
2005            BufferEvent::LanguageChanged(has_language) => {
2006                Event::LanguageChanged(buffer_id, *has_language)
2007            }
2008            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2009            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2010            BufferEvent::CapabilityChanged => {
2011                self.capability = buffer.read(cx).capability();
2012                return;
2013            }
2014            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2015        });
2016    }
2017
2018    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2019        let diff = diff.read(cx);
2020        let buffer_id = diff.buffer_id;
2021        let diff = DiffStateSnapshot {
2022            diff: diff.snapshot(cx),
2023            main_buffer: None,
2024        };
2025        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2026    }
2027
2028    fn inverted_buffer_diff_language_changed(
2029        &mut self,
2030        diff: Entity<BufferDiff>,
2031        main_buffer: Entity<language::Buffer>,
2032        cx: &mut Context<Self>,
2033    ) {
2034        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2035        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2036        let diff = diff.read(cx);
2037        let diff = DiffStateSnapshot {
2038            diff: diff.snapshot(cx),
2039            main_buffer: Some(main_buffer_snapshot),
2040        };
2041        self.snapshot
2042            .get_mut()
2043            .diffs
2044            .insert(base_text_buffer_id, diff);
2045    }
2046
2047    fn buffer_diff_changed(
2048        &mut self,
2049        diff: Entity<BufferDiff>,
2050        range: Range<text::Anchor>,
2051        cx: &mut Context<Self>,
2052    ) {
2053        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2054            return;
2055        };
2056        let snapshot = self.sync_mut(cx);
2057
2058        let diff = diff.read(cx);
2059        let buffer_id = diff.buffer_id;
2060
2061        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2062            return;
2063        };
2064        let new_diff = DiffStateSnapshot {
2065            diff: diff.snapshot(cx),
2066            main_buffer: None,
2067        };
2068        let base_text_changed = snapshot
2069            .diffs
2070            .get(&buffer_id)
2071            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2072        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2073
2074        let buffer = buffer.read(cx);
2075        let diff_change_range = range.to_offset(buffer);
2076
2077        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2078        let edits = Self::sync_diff_transforms(
2079            snapshot,
2080            excerpt_edits,
2081            DiffChangeKind::DiffUpdated {
2082                base_changed: base_text_changed,
2083            },
2084        );
2085        if !edits.is_empty() {
2086            self.subscriptions.publish(edits);
2087        }
2088        cx.emit(Event::Edited {
2089            edited_buffer: None,
2090        });
2091    }
2092
2093    fn inverted_buffer_diff_changed(
2094        &mut self,
2095        diff: Entity<BufferDiff>,
2096        main_buffer: Entity<language::Buffer>,
2097        diff_change_range: Option<Range<usize>>,
2098        cx: &mut Context<Self>,
2099    ) {
2100        let snapshot = self.sync_mut(cx);
2101
2102        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2103        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2104            return;
2105        };
2106
2107        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2108        let diff = diff.read(cx);
2109        let new_diff = DiffStateSnapshot {
2110            diff: diff.snapshot(cx),
2111            main_buffer: Some(main_buffer_snapshot),
2112        };
2113        snapshot
2114            .diffs
2115            .insert_or_replace(base_text_buffer_id, new_diff);
2116
2117        let Some(diff_change_range) = diff_change_range else {
2118            return;
2119        };
2120
2121        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2122        let edits = Self::sync_diff_transforms(
2123            snapshot,
2124            excerpt_edits,
2125            DiffChangeKind::DiffUpdated {
2126                // We don't read this field for inverted diffs.
2127                base_changed: false,
2128            },
2129        );
2130        if !edits.is_empty() {
2131            self.subscriptions.publish(edits);
2132        }
2133        cx.emit(Event::Edited {
2134            edited_buffer: None,
2135        });
2136    }
2137
2138    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2139        self.buffers.values().map(|state| state.buffer.clone())
2140    }
2141
2142    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2143        self.all_buffers_iter().collect()
2144    }
2145
2146    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2147        self.buffers.keys().copied()
2148    }
2149
2150    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2151        self.all_buffer_ids_iter().collect()
2152    }
2153
2154    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2155        self.buffers
2156            .get(&buffer_id)
2157            .map(|state| state.buffer.clone())
2158    }
2159
2160    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2161        self.point_to_buffer_offset(point, cx)
2162            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2163    }
2164
2165    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2166        let buffer_id = self
2167            .snapshot
2168            .borrow()
2169            .excerpts
2170            .first()
2171            .map(|excerpt| excerpt.buffer.remote_id());
2172        buffer_id
2173            .and_then(|buffer_id| self.buffer(buffer_id))
2174            .map(|buffer| {
2175                let buffer = buffer.read(cx);
2176                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2177            })
2178            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2179    }
2180
2181    pub fn language_settings_at<'a, T: ToOffset>(
2182        &'a self,
2183        point: T,
2184        cx: &'a App,
2185    ) -> Cow<'a, LanguageSettings> {
2186        let mut language = None;
2187        let mut file = None;
2188        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2189            let buffer = buffer.read(cx);
2190            language = buffer.language_at(offset);
2191            file = buffer.file();
2192        }
2193        language_settings(language.map(|l| l.name()), file, cx)
2194    }
2195
2196    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2197        self.buffers.values().for_each(|state| f(&state.buffer))
2198    }
2199
2200    pub fn explicit_title(&self) -> Option<&str> {
2201        self.title.as_deref()
2202    }
2203
2204    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2205        if let Some(title) = self.title.as_ref() {
2206            return title.into();
2207        }
2208
2209        if let Some(buffer) = self.as_singleton() {
2210            let buffer = buffer.read(cx);
2211
2212            if let Some(file) = buffer.file() {
2213                return file.file_name(cx).into();
2214            }
2215
2216            if let Some(title) = self.buffer_content_title(buffer) {
2217                return title;
2218            }
2219        };
2220
2221        "untitled".into()
2222    }
2223
2224    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2225        let mut is_leading_whitespace = true;
2226        let mut count = 0;
2227        let mut prev_was_space = false;
2228        let mut title = String::new();
2229
2230        for ch in buffer.snapshot().chars() {
2231            if is_leading_whitespace && ch.is_whitespace() {
2232                continue;
2233            }
2234
2235            is_leading_whitespace = false;
2236
2237            if ch == '\n' || count >= 40 {
2238                break;
2239            }
2240
2241            if ch.is_whitespace() {
2242                if !prev_was_space {
2243                    title.push(' ');
2244                    count += 1;
2245                    prev_was_space = true;
2246                }
2247            } else {
2248                title.push(ch);
2249                count += 1;
2250                prev_was_space = false;
2251            }
2252        }
2253
2254        let title = title.trim_end().to_string();
2255
2256        if title.is_empty() {
2257            return None;
2258        }
2259
2260        Some(title.into())
2261    }
2262
2263    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2264        self.title = Some(title);
2265        cx.notify();
2266    }
2267
2268    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2269    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2270        for buffer_state in self.buffers.values() {
2271            buffer_state
2272                .buffer
2273                .update(cx, |buffer, _cx| buffer.refresh_preview());
2274        }
2275    }
2276
2277    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2278    pub fn preserve_preview(&self, cx: &App) -> bool {
2279        self.buffers
2280            .values()
2281            .all(|state| state.buffer.read(cx).preserve_preview())
2282    }
2283
2284    #[cfg(any(test, feature = "test-support"))]
2285    pub fn is_parsing(&self, cx: &App) -> bool {
2286        self.as_singleton().unwrap().read(cx).is_parsing()
2287    }
2288
2289    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2290        let buffer_id = diff.read(cx).buffer_id;
2291
2292        if let Some(existing_diff) = self.diff_for(buffer_id)
2293            && diff.entity_id() == existing_diff.entity_id()
2294        {
2295            return;
2296        }
2297
2298        self.buffer_diff_changed(
2299            diff.clone(),
2300            text::Anchor::min_max_range_for_buffer(buffer_id),
2301            cx,
2302        );
2303        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2304    }
2305
2306    pub fn add_inverted_diff(
2307        &mut self,
2308        diff: Entity<BufferDiff>,
2309        main_buffer: Entity<language::Buffer>,
2310        cx: &mut Context<Self>,
2311    ) {
2312        let snapshot = diff.read(cx).base_text(cx);
2313        let base_text_buffer_id = snapshot.remote_id();
2314        let diff_change_range = 0..snapshot.len();
2315        self.snapshot.get_mut().has_inverted_diff = true;
2316        self.inverted_buffer_diff_changed(
2317            diff.clone(),
2318            main_buffer.clone(),
2319            Some(diff_change_range),
2320            cx,
2321        );
2322        self.diffs.insert(
2323            base_text_buffer_id,
2324            DiffState::new_inverted(diff, main_buffer, cx),
2325        );
2326    }
2327
2328    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2329        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2330    }
2331
2332    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2333        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2334    }
2335
2336    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2337        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2338    }
2339
2340    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2341        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2342        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2343    }
2344
2345    pub fn all_diff_hunks_expanded(&self) -> bool {
2346        self.snapshot.borrow().all_diff_hunks_expanded
2347    }
2348
2349    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2350        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2351        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2352    }
2353
2354    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2355        self.snapshot.get_mut().show_deleted_hunks = show;
2356
2357        self.sync_mut(cx);
2358
2359        let old_len = self.snapshot.borrow().len();
2360
2361        let ranges = std::iter::once((Point::zero()..Point::MAX, Anchor::Max));
2362        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2363
2364        let new_len = self.snapshot.borrow().len();
2365
2366        self.subscriptions.publish(vec![Edit {
2367            old: MultiBufferOffset(0)..old_len,
2368            new: MultiBufferOffset(0)..new_len,
2369        }]);
2370
2371        cx.emit(Event::DiffHunksToggled);
2372        cx.emit(Event::Edited {
2373            edited_buffer: None,
2374        });
2375    }
2376
2377    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2378        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2379    }
2380
2381    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2382        self.read(cx)
2383            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2384            .nth(1)
2385            .is_some()
2386    }
2387
2388    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2389        let snapshot = self.read(cx);
2390        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2391        let offset_range = range.to_offset(&snapshot);
2392        cursor.seek(&offset_range.start, Bias::Left);
2393        while let Some(item) = cursor.item() {
2394            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2395                break;
2396            }
2397            if item.hunk_info().is_some() {
2398                return true;
2399            }
2400            cursor.next();
2401        }
2402        false
2403    }
2404
2405    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2406        let snapshot = self.read(cx);
2407        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2408        for range in ranges {
2409            let range = range.to_point(&snapshot);
2410            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2411            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2412                .min(snapshot.len());
2413            cursor.seek(&start, Bias::Right);
2414            while let Some(item) = cursor.item() {
2415                if *cursor.start() >= end {
2416                    break;
2417                }
2418                if item.hunk_info().is_some() {
2419                    return true;
2420                }
2421                cursor.next();
2422            }
2423        }
2424        false
2425    }
2426
2427    pub fn expand_or_collapse_diff_hunks_inner(
2428        &mut self,
2429        // second element is the end of the last excerpt that should be considered for this range
2430        // (or Anchor::Max to opt out)
2431        ranges: impl IntoIterator<Item = (Range<Point>, Anchor)>,
2432        expand: bool,
2433        cx: &mut Context<Self>,
2434    ) -> Vec<Edit<MultiBufferOffset>> {
2435        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2436            return Vec::new();
2437        }
2438        self.sync_mut(cx);
2439        let mut snapshot = self.snapshot.get_mut();
2440        let mut excerpt_edits = Vec::new();
2441        let mut last_hunk_row = None;
2442        for (range, excerpt_end) in ranges {
2443            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2444                if diff_hunk
2445                    .multi_buffer_range()
2446                    .end
2447                    .cmp(&excerpt_end, &snapshot)
2448                    .is_gt()
2449                {
2450                    continue;
2451                }
2452                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2453                    continue;
2454                }
2455                let range = diff_hunk.multi_buffer_range();
2456                let start = snapshot.excerpt_offset_for_anchor(&range.start);
2457                let end = snapshot.excerpt_offset_for_anchor(&range.end);
2458                last_hunk_row = Some(diff_hunk.row_range.start);
2459                excerpt_edits.push(text::Edit {
2460                    old: start..end,
2461                    new: start..end,
2462                });
2463            }
2464        }
2465
2466        Self::sync_diff_transforms(
2467            &mut snapshot,
2468            excerpt_edits,
2469            DiffChangeKind::ExpandOrCollapseHunks { expand },
2470        )
2471    }
2472
2473    pub fn expand_or_collapse_diff_hunks(
2474        &mut self,
2475        ranges: Vec<Range<Anchor>>,
2476        expand: bool,
2477        cx: &mut Context<Self>,
2478    ) {
2479        let snapshot = self.snapshot.borrow().clone();
2480        let ranges = ranges.iter().map(move |range| {
2481            let excerpt_end = snapshot
2482                .excerpt_at(range.end)
2483                .map(|excerpt| excerpt.end_anchor().into())
2484                .unwrap_or(Anchor::Max);
2485            let range = range.to_point(&snapshot);
2486            let mut peek_end = range.end;
2487            if range.end.row < snapshot.max_row().0 {
2488                peek_end = Point::new(range.end.row + 1, 0);
2489            };
2490            (range.start..peek_end, excerpt_end)
2491        });
2492        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2493        if !edits.is_empty() {
2494            self.subscriptions.publish(edits);
2495        }
2496        cx.emit(Event::DiffHunksToggled);
2497        cx.emit(Event::Edited {
2498            edited_buffer: None,
2499        });
2500    }
2501
2502    #[ztracing::instrument(skip_all)]
2503    fn sync(&self, cx: &App) {
2504        let changed = self.buffer_changed_since_sync.replace(false);
2505        if !changed {
2506            return;
2507        }
2508        let edits = Self::sync_from_buffer_changes(
2509            &mut self.snapshot.borrow_mut(),
2510            &self.buffers,
2511            &self.diffs,
2512            cx,
2513        );
2514        if !edits.is_empty() {
2515            self.subscriptions.publish(edits);
2516        }
2517    }
2518
2519    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2520        let snapshot = self.snapshot.get_mut();
2521        let changed = self.buffer_changed_since_sync.replace(false);
2522        if !changed {
2523            return snapshot;
2524        }
2525        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2526
2527        if !edits.is_empty() {
2528            self.subscriptions.publish(edits);
2529        }
2530
2531        snapshot
2532    }
2533
2534    fn sync_from_buffer_changes(
2535        snapshot: &mut MultiBufferSnapshot,
2536        buffers: &BTreeMap<BufferId, BufferState>,
2537        diffs: &HashMap<BufferId, DiffState>,
2538        cx: &App,
2539    ) -> Vec<Edit<MultiBufferOffset>> {
2540        let MultiBufferSnapshot {
2541            excerpts,
2542            diffs: buffer_diff,
2543            path_keys_by_buffer,
2544            path_keys_by_index,
2545            diff_transforms: _,
2546            non_text_state_update_count,
2547            edit_count,
2548            is_dirty,
2549            has_deleted_file,
2550            has_conflict,
2551            has_inverted_diff: _,
2552            singleton: _,
2553            trailing_excerpt_update_count: _,
2554            all_diff_hunks_expanded: _,
2555            show_deleted_hunks: _,
2556            use_extended_diff_range: _,
2557            show_headers: _,
2558        } = snapshot;
2559        *is_dirty = false;
2560        *has_deleted_file = false;
2561        *has_conflict = false;
2562
2563        if !diffs.is_empty() {
2564            let mut diffs_to_add = Vec::new();
2565            for (id, diff) in diffs {
2566                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2567                // and use the diff hunk base text ranges to compute diff transforms.
2568                // Those base text ranges are usize, so make sure if the base text changed
2569                // we also update the diff snapshot so that we don't use stale offsets
2570                if buffer_diff.get(id).is_none_or(|existing_diff| {
2571                    if existing_diff.main_buffer.is_none() {
2572                        return false;
2573                    }
2574                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2575                    base_text.remote_id() != existing_diff.base_text().remote_id()
2576                        || base_text
2577                            .version()
2578                            .changed_since(existing_diff.base_text().version())
2579                }) {
2580                    if diffs_to_add.capacity() == 0 {
2581                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2582                        // meaning re-allocations will be fairly expensive
2583                        diffs_to_add.reserve(diffs.len());
2584                    }
2585                    diffs_to_add.push((*id, diff.snapshot(cx)));
2586                }
2587            }
2588            buffer_diff.extend(diffs_to_add);
2589        }
2590
2591        let mut paths_to_edit = Vec::new();
2592        let mut non_text_state_updated = false;
2593        let mut edited = false;
2594        for buffer_state in buffers.values() {
2595            let buffer = buffer_state.buffer.read(cx);
2596            let version = buffer.version();
2597            let non_text_state_update_count = buffer.non_text_state_update_count();
2598
2599            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2600            let buffer_non_text_state_updated =
2601                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2602            if (buffer_edited || buffer_non_text_state_updated)
2603                && let Some(path_key) = path_keys_by_buffer.get(&buffer.remote_id())
2604            {
2605                *buffer_state.last_version.borrow_mut() = version;
2606                buffer_state
2607                    .last_non_text_state_update_count
2608                    .set(non_text_state_update_count);
2609                paths_to_edit.push((path_key.clone(), buffer_state.buffer.clone(), buffer_edited));
2610            }
2611
2612            edited |= buffer_edited;
2613            non_text_state_updated |= buffer_non_text_state_updated;
2614            *is_dirty |= buffer.is_dirty();
2615            *has_deleted_file |= buffer
2616                .file()
2617                .is_some_and(|file| file.disk_state().is_deleted());
2618            *has_conflict |= buffer.has_conflict();
2619        }
2620        if edited {
2621            *edit_count += 1;
2622        }
2623        if non_text_state_updated {
2624            *non_text_state_update_count += 1;
2625        }
2626
2627        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path);
2628
2629        let mut edits = Vec::new();
2630        let mut new_excerpts = SumTree::default();
2631        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2632
2633        for (path, buffer, buffer_edited) in paths_to_edit {
2634            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2635            let old_excerpt = cursor.item().unwrap();
2636            let buffer = buffer.read(cx);
2637            let buffer_id = buffer.remote_id();
2638            let mut new_excerpt;
2639            if buffer_edited {
2640                edits.extend(
2641                    buffer
2642                        .edits_since_in_range::<usize>(
2643                            old_excerpt.buffer.version(),
2644                            old_excerpt.range.context.clone(),
2645                        )
2646                        .map(|edit| {
2647                            let excerpt_old_start = cursor.start().1;
2648                            let excerpt_new_start =
2649                                ExcerptDimension(new_excerpts.summary().text.len);
2650                            let old_start = excerpt_old_start + edit.old.start;
2651                            let old_end = excerpt_old_start + edit.old.end;
2652                            let new_start = excerpt_new_start + edit.new.start;
2653                            let new_end = excerpt_new_start + edit.new.end;
2654                            Edit {
2655                                old: old_start..old_end,
2656                                new: new_start..new_end,
2657                            }
2658                        }),
2659                );
2660
2661                new_excerpt = Excerpt::new(
2662                    path,
2663                    Arc::new(buffer.snapshot()),
2664                    old_excerpt.range.clone(),
2665                    old_excerpt.has_trailing_newline,
2666                );
2667            } else {
2668                new_excerpt = old_excerpt.clone();
2669                new_excerpt.buffer = Arc::new(buffer.snapshot());
2670            }
2671
2672            new_excerpts.push(new_excerpt, ());
2673            cursor.next();
2674        }
2675        new_excerpts.append(cursor.suffix(), ());
2676
2677        drop(cursor);
2678        *excerpts = new_excerpts;
2679
2680        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2681    }
2682
2683    fn sync_diff_transforms(
2684        snapshot: &mut MultiBufferSnapshot,
2685        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2686        change_kind: DiffChangeKind,
2687    ) -> Vec<Edit<MultiBufferOffset>> {
2688        if excerpt_edits.is_empty() {
2689            return vec![];
2690        }
2691
2692        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2693        let mut old_diff_transforms = snapshot
2694            .diff_transforms
2695            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2696        let mut new_diff_transforms = SumTree::default();
2697        let mut old_expanded_hunks = HashSet::default();
2698        let mut output_edits = Vec::new();
2699        let mut output_delta = 0_isize;
2700        let mut at_transform_boundary = true;
2701        let mut end_of_current_insert = None;
2702
2703        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2704        while let Some(edit) = excerpt_edits.next() {
2705            excerpts.seek_forward(&edit.new.start, Bias::Right);
2706            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2707                excerpts.prev();
2708            }
2709
2710            // Keep any transforms that are before the edit.
2711            if at_transform_boundary {
2712                at_transform_boundary = false;
2713                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2714                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2715                if let Some(transform) = old_diff_transforms.item()
2716                    && old_diff_transforms.end().0 == edit.old.start
2717                    && old_diff_transforms.start().0 < edit.old.start
2718                {
2719                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2720                    old_diff_transforms.next();
2721                }
2722            }
2723
2724            // Compute the start of the edit in output coordinates.
2725            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2726            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2727            let edit_new_start =
2728                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2729
2730            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2731                &edit,
2732                &mut excerpts,
2733                &mut old_diff_transforms,
2734                &mut new_diff_transforms,
2735                &mut end_of_current_insert,
2736                &mut old_expanded_hunks,
2737                snapshot,
2738                change_kind,
2739            );
2740
2741            // Compute the end of the edit in output coordinates.
2742            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2743            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2744            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2745            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2746            let output_edit = Edit {
2747                old: edit_old_start..edit_old_end,
2748                new: edit_new_start..edit_new_end,
2749            };
2750
2751            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2752            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2753            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2754                output_edits.push(output_edit);
2755            }
2756
2757            // If this is the last edit that intersects the current diff transform,
2758            // then recreate the content up to the end of this transform, to prepare
2759            // for reusing additional slices of the old transforms.
2760            if excerpt_edits
2761                .peek()
2762                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2763            {
2764                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2765                    && match old_diff_transforms.item() {
2766                        Some(DiffTransform::BufferContent {
2767                            inserted_hunk_info: Some(hunk),
2768                            ..
2769                        }) => excerpts.item().is_some_and(|excerpt| {
2770                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2771                                && diff.main_buffer.is_some()
2772                            {
2773                                return true;
2774                            }
2775                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2776                        }),
2777                        _ => true,
2778                    };
2779
2780                let mut excerpt_offset = edit.new.end;
2781                if !keep_next_old_transform {
2782                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2783                    old_diff_transforms.next();
2784                }
2785
2786                old_expanded_hunks.clear();
2787                Self::push_buffer_content_transform(
2788                    snapshot,
2789                    &mut new_diff_transforms,
2790                    excerpt_offset,
2791                    end_of_current_insert,
2792                );
2793                at_transform_boundary = true;
2794            }
2795        }
2796
2797        // Keep any transforms that are after the last edit.
2798        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2799
2800        // Ensure there's always at least one buffer content transform.
2801        if new_diff_transforms.is_empty() {
2802            new_diff_transforms.push(
2803                DiffTransform::BufferContent {
2804                    summary: Default::default(),
2805                    inserted_hunk_info: None,
2806                },
2807                (),
2808            );
2809        }
2810
2811        drop(old_diff_transforms);
2812        drop(excerpts);
2813        snapshot.diff_transforms = new_diff_transforms;
2814        snapshot.edit_count += 1;
2815
2816        #[cfg(any(test, feature = "test-support"))]
2817        snapshot.check_invariants();
2818        output_edits
2819    }
2820
2821    fn recompute_diff_transforms_for_edit(
2822        edit: &Edit<ExcerptOffset>,
2823        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2824        old_diff_transforms: &mut Cursor<
2825            DiffTransform,
2826            Dimensions<ExcerptOffset, MultiBufferOffset>,
2827        >,
2828        new_diff_transforms: &mut SumTree<DiffTransform>,
2829        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2830        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2831        snapshot: &MultiBufferSnapshot,
2832        change_kind: DiffChangeKind,
2833    ) -> bool {
2834        log::trace!(
2835            "recomputing diff transform for edit {:?} => {:?}",
2836            edit.old.start..edit.old.end,
2837            edit.new.start..edit.new.end
2838        );
2839
2840        // Record which hunks were previously expanded.
2841        while let Some(item) = old_diff_transforms.item() {
2842            if let Some(hunk_info) = item.hunk_info() {
2843                log::trace!(
2844                    "previously expanded hunk at {:?}",
2845                    old_diff_transforms.start()
2846                );
2847                old_expanded_hunks.insert(hunk_info);
2848            }
2849            if old_diff_transforms.end().0 > edit.old.end {
2850                break;
2851            }
2852            old_diff_transforms.next();
2853        }
2854
2855        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2856        // For inverted diffs, hunks are always shown, so we can't skip this.
2857        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2858        if old_expanded_hunks.is_empty()
2859            && change_kind == DiffChangeKind::BufferEdited
2860            && !all_diff_hunks_expanded
2861            && !snapshot.has_inverted_diff
2862        {
2863            return false;
2864        }
2865
2866        // Visit each excerpt that intersects the edit.
2867        let mut did_expand_hunks = false;
2868        while let Some(excerpt) = excerpts.item() {
2869            // Recompute the expanded hunks in the portion of the excerpt that
2870            // intersects the edit.
2871            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2872                let buffer = &excerpt.buffer;
2873                let excerpt_start = *excerpts.start();
2874                let excerpt_end = excerpt_start + excerpt.text_summary.len;
2875                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2876                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2877                let edit_buffer_start =
2878                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
2879                let edit_buffer_end =
2880                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
2881                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2882
2883                if let Some(main_buffer) = &diff.main_buffer {
2884                    for hunk in diff.hunks_intersecting_base_text_range(
2885                        edit_buffer_start..edit_buffer_end,
2886                        main_buffer,
2887                    ) {
2888                        did_expand_hunks = true;
2889                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
2890                        if hunk_buffer_range.start < excerpt_buffer_start {
2891                            log::trace!("skipping hunk that starts before excerpt");
2892                            continue;
2893                        }
2894                        hunk_buffer_range.end.to_point(&excerpt.buffer);
2895                        let hunk_excerpt_start = excerpt_start
2896                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2897                        let hunk_excerpt_end = excerpt_end
2898                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2899                        Self::push_buffer_content_transform(
2900                            snapshot,
2901                            new_diff_transforms,
2902                            hunk_excerpt_start,
2903                            *end_of_current_insert,
2904                        );
2905                        if !hunk_buffer_range.is_empty() {
2906                            let hunk_info = DiffTransformHunkInfo {
2907                                buffer_id: buffer.remote_id(),
2908                                hunk_start_anchor: hunk.buffer_range.start,
2909                                hunk_secondary_status: hunk.secondary_status,
2910                                is_logically_deleted: true,
2911                            };
2912                            *end_of_current_insert =
2913                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2914                        }
2915                    }
2916                } else {
2917                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
2918                        ..buffer.anchor_after(edit_buffer_end);
2919                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2920                        if hunk.is_created_file() && !all_diff_hunks_expanded {
2921                            continue;
2922                        }
2923
2924                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2925                        if hunk_buffer_range.start < excerpt_buffer_start {
2926                            log::trace!("skipping hunk that starts before excerpt");
2927                            continue;
2928                        }
2929
2930                        let hunk_info = DiffTransformHunkInfo {
2931                            buffer_id: buffer.remote_id(),
2932                            hunk_start_anchor: hunk.buffer_range.start,
2933                            hunk_secondary_status: hunk.secondary_status,
2934                            is_logically_deleted: false,
2935                        };
2936
2937                        let hunk_excerpt_start = excerpt_start
2938                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2939                        let hunk_excerpt_end = excerpt_end
2940                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2941
2942                        Self::push_buffer_content_transform(
2943                            snapshot,
2944                            new_diff_transforms,
2945                            hunk_excerpt_start,
2946                            *end_of_current_insert,
2947                        );
2948
2949                        // For every existing hunk, determine if it was previously expanded
2950                        // and if it should currently be expanded.
2951                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2952                        let should_expand_hunk = match &change_kind {
2953                            DiffChangeKind::DiffUpdated { base_changed: true } => {
2954                                was_previously_expanded || all_diff_hunks_expanded
2955                            }
2956                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2957                                let intersects = hunk_buffer_range.is_empty()
2958                                    || hunk_buffer_range.end > edit_buffer_start;
2959                                if *expand {
2960                                    intersects || was_previously_expanded || all_diff_hunks_expanded
2961                                } else {
2962                                    !intersects
2963                                        && (was_previously_expanded || all_diff_hunks_expanded)
2964                                }
2965                            }
2966                            _ => was_previously_expanded || all_diff_hunks_expanded,
2967                        };
2968
2969                        if should_expand_hunk {
2970                            did_expand_hunks = true;
2971                            log::trace!(
2972                                "expanding hunk {:?}, excerpt:{:?}",
2973                                hunk_excerpt_start..hunk_excerpt_end,
2974                                excerpt.id
2975                            );
2976
2977                            if !hunk.diff_base_byte_range.is_empty()
2978                                && hunk_buffer_range.start >= edit_buffer_start
2979                                && hunk_buffer_range.start <= excerpt_buffer_end
2980                                && snapshot.show_deleted_hunks
2981                            {
2982                                let base_text = diff.base_text();
2983                                let mut text_cursor =
2984                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2985                                let mut base_text_summary = text_cursor
2986                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
2987
2988                                let mut has_trailing_newline = false;
2989                                if base_text_summary.last_line_chars > 0 {
2990                                    base_text_summary += TextSummary::newline();
2991                                    has_trailing_newline = true;
2992                                }
2993
2994                                new_diff_transforms.push(
2995                                    DiffTransform::DeletedHunk {
2996                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
2997                                        summary: base_text_summary,
2998                                        buffer_id: excerpt.buffer.remote_id(),
2999                                        hunk_info,
3000                                        has_trailing_newline,
3001                                    },
3002                                    (),
3003                                );
3004                            }
3005
3006                            if !hunk_buffer_range.is_empty() {
3007                                *end_of_current_insert =
3008                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3009                            }
3010                        }
3011                    }
3012                }
3013            }
3014
3015            if excerpts.end() <= edit.new.end {
3016                excerpts.next();
3017            } else {
3018                break;
3019            }
3020        }
3021
3022        did_expand_hunks || !old_expanded_hunks.is_empty()
3023    }
3024
3025    fn append_diff_transforms(
3026        new_transforms: &mut SumTree<DiffTransform>,
3027        subtree: SumTree<DiffTransform>,
3028    ) {
3029        if let Some(DiffTransform::BufferContent {
3030            inserted_hunk_info,
3031            summary,
3032        }) = subtree.first()
3033            && Self::extend_last_buffer_content_transform(
3034                new_transforms,
3035                *inserted_hunk_info,
3036                *summary,
3037            )
3038        {
3039            let mut cursor = subtree.cursor::<()>(());
3040            cursor.next();
3041            cursor.next();
3042            new_transforms.append(cursor.suffix(), ());
3043            return;
3044        }
3045        new_transforms.append(subtree, ());
3046    }
3047
3048    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3049        if let DiffTransform::BufferContent {
3050            inserted_hunk_info: inserted_hunk_anchor,
3051            summary,
3052        } = transform
3053            && Self::extend_last_buffer_content_transform(
3054                new_transforms,
3055                inserted_hunk_anchor,
3056                summary,
3057            )
3058        {
3059            return;
3060        }
3061        new_transforms.push(transform, ());
3062    }
3063
3064    fn push_buffer_content_transform(
3065        old_snapshot: &MultiBufferSnapshot,
3066        new_transforms: &mut SumTree<DiffTransform>,
3067        end_offset: ExcerptOffset,
3068        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3069    ) {
3070        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3071            (end_offset.min(insertion_end_offset), Some(hunk_info))
3072        });
3073        let unchanged_region = [(end_offset, None)];
3074
3075        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3076        {
3077            let start_offset = new_transforms.summary().excerpt_len();
3078            if end_offset <= start_offset {
3079                continue;
3080            }
3081            let summary_to_add = old_snapshot
3082                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3083
3084            if !Self::extend_last_buffer_content_transform(
3085                new_transforms,
3086                inserted_hunk_info,
3087                summary_to_add,
3088            ) {
3089                new_transforms.push(
3090                    DiffTransform::BufferContent {
3091                        summary: summary_to_add,
3092                        inserted_hunk_info,
3093                    },
3094                    (),
3095                )
3096            }
3097        }
3098    }
3099
3100    fn extend_last_buffer_content_transform(
3101        new_transforms: &mut SumTree<DiffTransform>,
3102        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3103        summary_to_add: MBTextSummary,
3104    ) -> bool {
3105        let mut did_extend = false;
3106        new_transforms.update_last(
3107            |last_transform| {
3108                if let DiffTransform::BufferContent {
3109                    summary,
3110                    inserted_hunk_info: inserted_hunk_anchor,
3111                } = last_transform
3112                    && *inserted_hunk_anchor == new_inserted_hunk_info
3113                {
3114                    *summary += summary_to_add;
3115                    did_extend = true;
3116                }
3117            },
3118            (),
3119        );
3120        did_extend
3121    }
3122
3123    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3124        let snapshot = self.snapshot(cx);
3125        let excerpt_end = snapshot
3126            .excerpt_at(range.end)
3127            .map(|excerpt| excerpt.end_anchor().into())
3128            .unwrap_or(Anchor::Max);
3129        let point_range = range.to_point(&snapshot);
3130        let expand = !self.single_hunk_is_expanded(range, cx);
3131        let edits =
3132            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_end)], expand, cx);
3133        if !edits.is_empty() {
3134            self.subscriptions.publish(edits);
3135        }
3136        cx.emit(Event::DiffHunksToggled);
3137        cx.emit(Event::Edited {
3138            edited_buffer: None,
3139        });
3140    }
3141}
3142
3143fn build_excerpt_ranges(
3144    ranges: impl IntoIterator<Item = Range<Point>>,
3145    context_line_count: u32,
3146    buffer_snapshot: &BufferSnapshot,
3147) -> Vec<ExcerptRange<Point>> {
3148    ranges
3149        .into_iter()
3150        .map(|range| {
3151            let start_row = range.start.row.saturating_sub(context_line_count);
3152            let start = Point::new(start_row, 0);
3153            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3154            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3155            ExcerptRange {
3156                context: start..end,
3157                primary: range,
3158            }
3159        })
3160        .collect()
3161}
3162
3163#[cfg(any(test, feature = "test-support"))]
3164impl MultiBuffer {
3165    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3166        let buffer = cx.new(|cx| Buffer::local(text, cx));
3167        cx.new(|cx| Self::singleton(buffer, cx))
3168    }
3169
3170    pub fn build_multi<const COUNT: usize>(
3171        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3172        cx: &mut gpui::App,
3173    ) -> Entity<Self> {
3174        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3175        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3176            let buffer = cx.new(|cx| Buffer::local(text, cx));
3177            let snapshot = buffer.read(cx).snapshot();
3178            let excerpt_ranges = ranges
3179                .into_iter()
3180                .map(ExcerptRange::new)
3181                .collect::<Vec<_>>();
3182            multi.update(cx, |multi, cx| {
3183                multi.set_excerpt_ranges_for_path(
3184                    PathKey::sorted(ix as u64),
3185                    buffer,
3186                    &snapshot,
3187                    excerpt_ranges,
3188                    cx,
3189                )
3190            });
3191        }
3192
3193        multi
3194    }
3195
3196    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3197        cx.new(|cx| Self::singleton(buffer, cx))
3198    }
3199
3200    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3201        cx.new(|cx| {
3202            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3203            let mutation_count = rng.random_range(1..=5);
3204            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3205            multibuffer
3206        })
3207    }
3208
3209    pub fn randomly_edit(
3210        &mut self,
3211        rng: &mut impl rand::Rng,
3212        edit_count: usize,
3213        cx: &mut Context<Self>,
3214    ) {
3215        use util::RandomCharIter;
3216
3217        let snapshot = self.read(cx);
3218        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3219        let mut last_end = None;
3220        for _ in 0..edit_count {
3221            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3222                break;
3223            }
3224
3225            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3226            let end =
3227                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3228            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3229            last_end = Some(end);
3230
3231            let mut range = start..end;
3232            if rng.random_bool(0.2) {
3233                mem::swap(&mut range.start, &mut range.end);
3234            }
3235
3236            let new_text_len = rng.random_range(0..10);
3237            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3238
3239            edits.push((range, new_text.into()));
3240        }
3241        log::info!("mutating multi-buffer with {:?}", edits);
3242        drop(snapshot);
3243
3244        self.edit(edits, None, cx);
3245    }
3246
3247    pub fn randomly_edit_excerpts(
3248        &mut self,
3249        rng: &mut impl rand::Rng,
3250        mutation_count: usize,
3251        cx: &mut Context<Self>,
3252    ) {
3253        use rand::prelude::*;
3254        use std::env;
3255        use util::RandomCharIter;
3256
3257        let max_excerpts = env::var("MAX_EXCERPTS")
3258            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3259            .unwrap_or(5);
3260
3261        let mut buffers = Vec::new();
3262        for _ in 0..mutation_count {
3263            if rng.random_bool(0.05) {
3264                log::info!("Clearing multi-buffer");
3265                self.clear(cx);
3266                continue;
3267            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3268                let ids = self.excerpt_ids();
3269                let mut excerpts = HashSet::default();
3270                for _ in 0..rng.random_range(0..ids.len()) {
3271                    excerpts.extend(ids.choose(rng).copied());
3272                }
3273
3274                let line_count = rng.random_range(0..5);
3275
3276                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3277
3278                self.expand_excerpts(
3279                    excerpts.iter().cloned(),
3280                    line_count,
3281                    ExpandExcerptDirection::UpAndDown,
3282                    cx,
3283                );
3284                continue;
3285            }
3286
3287            let excerpt_ids = self.excerpt_ids();
3288            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3289                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3290                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3291                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3292                    let buffer = buffers.last().unwrap().read(cx);
3293                    log::info!(
3294                        "Creating new buffer {} with text: {:?}",
3295                        buffer.remote_id(),
3296                        buffer.text()
3297                    );
3298                    buffers.last().unwrap().clone()
3299                } else {
3300                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3301                };
3302
3303                let buffer = buffer_handle.read(cx);
3304                let buffer_text = buffer.text();
3305                let ranges = (0..rng.random_range(0..5))
3306                    .map(|_| {
3307                        let end_ix =
3308                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3309                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3310                        ExcerptRange::new(start_ix..end_ix)
3311                    })
3312                    .collect::<Vec<_>>();
3313                log::info!(
3314                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3315                    buffer_handle.read(cx).remote_id(),
3316                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3317                    ranges
3318                        .iter()
3319                        .map(|r| &buffer_text[r.context.clone()])
3320                        .collect::<Vec<_>>()
3321                );
3322
3323                let excerpt_id =
3324                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3325                log::info!("Inserted with ids: {:?}", excerpt_id);
3326            } else {
3327                let remove_count = rng.random_range(1..=excerpt_ids.len());
3328                let mut excerpts_to_remove = excerpt_ids
3329                    .choose_multiple(rng, remove_count)
3330                    .cloned()
3331                    .collect::<Vec<_>>();
3332                let snapshot = self.snapshot.borrow();
3333                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3334                drop(snapshot);
3335                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3336                self.remove_excerpts(excerpts_to_remove, cx);
3337            }
3338        }
3339    }
3340
3341    pub fn randomly_mutate(
3342        &mut self,
3343        rng: &mut impl rand::Rng,
3344        mutation_count: usize,
3345        cx: &mut Context<Self>,
3346    ) {
3347        use rand::prelude::*;
3348
3349        if rng.random_bool(0.7) || self.singleton {
3350            let buffer = self
3351                .buffers
3352                .values()
3353                .choose(rng)
3354                .map(|state| state.buffer.clone());
3355
3356            if let Some(buffer) = buffer {
3357                buffer.update(cx, |buffer, cx| {
3358                    if rng.random() {
3359                        buffer.randomly_edit(rng, mutation_count, cx);
3360                    } else {
3361                        buffer.randomly_undo_redo(rng, cx);
3362                    }
3363                });
3364            } else {
3365                self.randomly_edit(rng, mutation_count, cx);
3366            }
3367        } else {
3368            self.randomly_edit_excerpts(rng, mutation_count, cx);
3369        }
3370
3371        self.check_invariants(cx);
3372    }
3373
3374    fn check_invariants(&self, cx: &App) {
3375        self.read(cx).check_invariants();
3376    }
3377}
3378
3379impl EventEmitter<Event> for MultiBuffer {}
3380
3381impl MultiBufferSnapshot {
3382    pub fn text(&self) -> String {
3383        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3384            .map(|chunk| chunk.text)
3385            .collect()
3386    }
3387
3388    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3389        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3390            .flat_map(|c| c.chars().rev())
3391    }
3392
3393    fn reversed_chunks_in_range(
3394        &self,
3395        range: Range<MultiBufferOffset>,
3396    ) -> ReversedMultiBufferChunks<'_> {
3397        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3398        cursor.seek(&range.end);
3399        let current_chunks = cursor.region().as_ref().map(|region| {
3400            let start_overshoot = range.start.saturating_sub(region.range.start);
3401            let end_overshoot = range.end - region.range.start;
3402            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3403            let start = region.buffer_range.start + start_overshoot;
3404            region.buffer.reversed_chunks_in_range(start..end)
3405        });
3406        ReversedMultiBufferChunks {
3407            cursor,
3408            current_chunks,
3409            start: range.start,
3410            offset: range.end,
3411        }
3412    }
3413
3414    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3415        let offset = position.to_offset(self);
3416        self.text_for_range(offset..self.len())
3417            .flat_map(|chunk| chunk.chars())
3418    }
3419
3420    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3421        self.chunks(range, false).map(|chunk| chunk.text)
3422    }
3423
3424    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3425        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3426            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3427    }
3428
3429    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3430    where
3431        T: ToOffset,
3432    {
3433        let position = position.to_offset(self);
3434        position == self.clip_offset(position, Bias::Left)
3435            && self
3436                .bytes_in_range(position..self.len())
3437                .flatten()
3438                .copied()
3439                .take(needle.len())
3440                .eq(needle.bytes())
3441    }
3442
3443    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3444        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3445    }
3446
3447    pub fn diff_hunks_in_range<T: ToPoint>(
3448        &self,
3449        range: Range<T>,
3450    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3451        let query_range = range.start.to_point(self)..range.end.to_point(self);
3452        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3453            let diff = self.diffs.get(&buffer.remote_id())?;
3454            let iter = if let Some(main_buffer) = &diff.main_buffer {
3455                let buffer_start = buffer.point_to_offset(buffer_range.start);
3456                let buffer_end = buffer.point_to_offset(buffer_range.end);
3457                itertools::Either::Left(
3458                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3459                        .map(move |hunk| (hunk, buffer, true)),
3460                )
3461            } else {
3462                let buffer_start = buffer.anchor_before(buffer_range.start);
3463                let buffer_end = buffer.anchor_after(buffer_range.end);
3464                itertools::Either::Right(
3465                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3466                        .map(move |hunk| (hunk, buffer, false)),
3467                )
3468            };
3469            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3470                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3471                    return None;
3472                }
3473                let range = if is_inverted {
3474                    hunk.diff_base_byte_range.to_point(&buffer)
3475                } else {
3476                    hunk.range.clone()
3477                };
3478                Some((range, (hunk, is_inverted)))
3479            }))
3480        })
3481        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3482            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3483            {
3484                return None;
3485            }
3486            let end_row = if range.end.column == 0 {
3487                range.end.row
3488            } else {
3489                range.end.row + 1
3490            };
3491
3492            let word_diffs =
3493                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3494                    .then(|| {
3495                        let mut word_diffs = Vec::new();
3496
3497                        if self.show_deleted_hunks || is_inverted {
3498                            let hunk_start_offset = if is_inverted {
3499                                Anchor::in_buffer(
3500                                    excerpt.path_key_index,
3501                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3502                                )
3503                                .to_offset(self)
3504                            } else {
3505                                Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3506                                    .to_offset(self)
3507                            };
3508
3509                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3510                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3511                            }));
3512                        }
3513
3514                        if !is_inverted {
3515                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3516                                Anchor::range_in_buffer(excerpt.path_key_index, diff)
3517                                    .to_offset(self)
3518                            }));
3519                        }
3520                        word_diffs
3521                    })
3522                    .unwrap_or_default();
3523
3524            let buffer_range = if is_inverted {
3525                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3526                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3527            } else {
3528                hunk.buffer_range.clone()
3529            };
3530            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3531                DiffHunkStatusKind::Deleted
3532            } else if hunk.diff_base_byte_range.is_empty() {
3533                DiffHunkStatusKind::Added
3534            } else {
3535                DiffHunkStatusKind::Modified
3536            };
3537            Some(MultiBufferDiffHunk {
3538                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3539                buffer_id: excerpt.buffer.remote_id(),
3540                buffer_range,
3541                word_diffs,
3542                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3543                    ..BufferOffset(hunk.diff_base_byte_range.end),
3544                status: DiffHunkStatus {
3545                    kind: status_kind,
3546                    secondary: hunk.secondary_status,
3547                },
3548            })
3549        })
3550    }
3551
3552    fn excerpts_for_range<T: ToOffset>(
3553        &self,
3554        range: Range<T>,
3555    ) -> impl Iterator<Item = &Excerpt> + '_ {
3556        let range = range.start.to_offset(self)..range.end.to_offset(self);
3557        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3558        cursor.seek(&range.start);
3559        std::iter::from_fn(move || {
3560            let region = cursor.region()?;
3561            if region.range.start > range.end
3562                || region.range.start == range.end && region.range.start > range.start
3563            {
3564                return None;
3565            }
3566            let excerpt = region.excerpt;
3567            cursor.next_excerpt_forwards();
3568            Some(excerpt)
3569        })
3570    }
3571
3572    // todo!() repeats ids? seems weird
3573    pub fn buffer_ids_for_range<T: ToOffset>(
3574        &self,
3575        range: Range<T>,
3576    ) -> impl Iterator<Item = BufferId> + '_ {
3577        self.excerpts_for_range(range)
3578            .map(|excerpt| excerpt.buffer.remote_id())
3579    }
3580
3581    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3582    ///
3583    /// The passed in anchors must be ordered.
3584    pub fn text_anchors_to_visible_anchors(
3585        &self,
3586        anchors: impl IntoIterator<Item = text::Anchor>,
3587    ) -> Vec<Option<Anchor>> {
3588        let anchors = anchors.into_iter();
3589        let mut result = Vec::with_capacity(anchors.size_hint().0);
3590        let mut anchors = anchors.peekable();
3591        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3592        'anchors: while let Some(anchor) = anchors.peek() {
3593            let Some(buffer_id) = anchor.buffer_id else {
3594                anchors.next();
3595                result.push(None);
3596                continue 'anchors;
3597            };
3598            let mut same_buffer_anchors =
3599                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3600
3601            if let Some(path) = self.path_keys_by_buffer.get(&buffer_id) {
3602                let Some(mut next) = same_buffer_anchors.next() else {
3603                    continue 'anchors;
3604                };
3605                cursor.seek_forward(path, Bias::Left);
3606                'excerpts: loop {
3607                    let Some(excerpt) = cursor.item() else {
3608                        break;
3609                    };
3610                    if &excerpt.path_key != path {
3611                        break;
3612                    }
3613
3614                    loop {
3615                        // anchor is before the first excerpt
3616                        if excerpt
3617                            .range
3618                            .context
3619                            .start
3620                            .cmp(&next, &excerpt.buffer)
3621                            .is_gt()
3622                        {
3623                            // so we skip it and try the next anchor
3624                            result.push(None);
3625                            match same_buffer_anchors.next() {
3626                                Some(anchor) => next = anchor,
3627                                None => continue 'anchors,
3628                            }
3629                        // anchor is within the excerpt
3630                        } else if excerpt
3631                            .range
3632                            .context
3633                            .end
3634                            .cmp(&next, &excerpt.buffer)
3635                            .is_ge()
3636                        {
3637                            // record it and all following anchors that are within
3638                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3639                            result.extend(
3640                                same_buffer_anchors
3641                                    .peeking_take_while(|a| {
3642                                        excerpt.range.context.end.cmp(a, &excerpt.buffer).is_ge()
3643                                    })
3644                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3645                            );
3646                            match same_buffer_anchors.next() {
3647                                Some(anchor) => next = anchor,
3648                                None => continue 'anchors,
3649                            }
3650                        // anchor is after the excerpt, try the next one
3651                        } else {
3652                            cursor.next();
3653                            continue 'excerpts;
3654                        }
3655                    }
3656                }
3657                // account for `next`
3658                result.push(None);
3659            }
3660            result.extend(same_buffer_anchors.map(|_| None));
3661        }
3662
3663        result
3664    }
3665
3666    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3667        &self,
3668        ranges: impl Iterator<Item = Range<T>>,
3669    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3670        ranges.flat_map(|range| {
3671            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3672                .into_iter()
3673        })
3674    }
3675
3676    pub fn range_to_buffer_ranges<R, T>(
3677        &self,
3678        range: R,
3679    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
3680    where
3681        R: RangeBounds<T>,
3682        T: ToOffset,
3683    {
3684        self.range_to_buffer_ranges_with_context(range)
3685            .into_iter()
3686            .map(|(buffer, range, id, _context)| (buffer, range, id))
3687            .collect()
3688    }
3689
3690    pub fn range_to_buffer_ranges_with_context<R, T>(
3691        &self,
3692        range: R,
3693    ) -> Vec<(
3694        &BufferSnapshot,
3695        Range<BufferOffset>,
3696        ExcerptId,
3697        Range<text::Anchor>,
3698    )>
3699    where
3700        R: RangeBounds<T>,
3701        T: ToOffset,
3702    {
3703        let start = match range.start_bound() {
3704            Bound::Included(start) => start.to_offset(self),
3705            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3706            Bound::Unbounded => MultiBufferOffset::ZERO,
3707        };
3708        let end_bound = match range.end_bound() {
3709            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3710            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3711            Bound::Unbounded => Bound::Unbounded,
3712        };
3713        let bounds = (Bound::Included(start), end_bound);
3714
3715        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3716        cursor.seek(&start);
3717
3718        let mut result: Vec<(
3719            &BufferSnapshot,
3720            Range<BufferOffset>,
3721            ExcerptId,
3722            Range<text::Anchor>,
3723        )> = Vec::new();
3724        while let Some(region) = cursor.region() {
3725            let dominated_by_end_bound = match end_bound {
3726                Bound::Included(end) => region.range.start > end,
3727                Bound::Excluded(end) => region.range.start >= end,
3728                Bound::Unbounded => false,
3729            };
3730            if dominated_by_end_bound {
3731                break;
3732            }
3733            if region.is_main_buffer {
3734                let start_overshoot = start.saturating_sub(region.range.start);
3735                let end_offset = match end_bound {
3736                    Bound::Included(end) | Bound::Excluded(end) => end,
3737                    Bound::Unbounded => region.range.end,
3738                };
3739                let end_overshoot = end_offset.saturating_sub(region.range.start);
3740                let start = region
3741                    .buffer_range
3742                    .end
3743                    .min(region.buffer_range.start + start_overshoot);
3744                let end = region
3745                    .buffer_range
3746                    .end
3747                    .min(region.buffer_range.start + end_overshoot);
3748                let context = region.excerpt.range.context.clone();
3749                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
3750                    *excerpt_id == region.excerpt.id && prev_range.end == start
3751                }) {
3752                    prev.1.end = end;
3753                } else {
3754                    result.push((region.buffer, start..end, region.excerpt.id, context));
3755                }
3756            }
3757            cursor.next();
3758        }
3759
3760        if let Some(excerpt) = cursor.excerpt() {
3761            let dominated_by_prev_excerpt =
3762                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
3763            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3764                let excerpt_position = self.len();
3765                if bounds.contains(&excerpt_position) {
3766                    let buffer_offset =
3767                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
3768                    let context = excerpt.range.context.clone();
3769                    result.push((
3770                        &excerpt.buffer,
3771                        buffer_offset..buffer_offset,
3772                        excerpt.id,
3773                        context,
3774                    ));
3775                }
3776            }
3777        }
3778
3779        result
3780    }
3781
3782    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3783        &self,
3784        range: Range<T>,
3785    ) -> impl Iterator<
3786        Item = (
3787            &BufferSnapshot,
3788            Range<BufferOffset>,
3789            ExcerptId,
3790            Option<Anchor>,
3791        ),
3792    > + '_ {
3793        let start = range.start.to_offset(self);
3794        let end = range.end.to_offset(self);
3795
3796        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3797        cursor.seek(&start);
3798
3799        std::iter::from_fn(move || {
3800            let region = cursor.region()?;
3801            if region.range.start > end {
3802                return None;
3803            }
3804            let start_overshoot = start.saturating_sub(region.range.start);
3805            let end_overshoot = end.saturating_sub(region.range.start);
3806            let start = region
3807                .buffer_range
3808                .end
3809                .min(region.buffer_range.start + start_overshoot);
3810            let end = region
3811                .buffer_range
3812                .end
3813                .min(region.buffer_range.start + end_overshoot);
3814
3815            let region_excerpt_id = region.excerpt.id;
3816            let deleted_hunk_anchor = if region.is_main_buffer {
3817                None
3818            } else {
3819                Some(self.anchor_before(region.range.start))
3820            };
3821            let result = (
3822                region.buffer,
3823                start..end,
3824                region_excerpt_id,
3825                deleted_hunk_anchor,
3826            );
3827            cursor.next();
3828            Some(result)
3829        })
3830    }
3831
3832    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3833    /// coordinates.
3834    ///
3835    /// The given callback will be called for every excerpt intersecting the given range. It will
3836    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3837    /// The callback should return an iterator of metadata items from that buffer, each paired
3838    /// with a buffer range.
3839    ///
3840    /// The returned iterator yields each of these metadata items, paired with its range in
3841    /// multi-buffer coordinates.
3842    fn lift_buffer_metadata<'a, MBD, M, I>(
3843        &'a self,
3844        query_range: Range<MBD>,
3845        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3846    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3847    where
3848        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3849        MBD: MultiBufferDimension
3850            + Ord
3851            + Sub<Output = MBD::TextDimension>
3852            + ops::Add<MBD::TextDimension, Output = MBD>
3853            + ops::AddAssign<MBD::TextDimension>,
3854        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3855            + ops::Add<Output = MBD::TextDimension>
3856            + AddAssign<MBD::TextDimension>
3857            + Ord,
3858    {
3859        let mut current_excerpt_metadata: Option<(Excerpt, I)> = None;
3860        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3861
3862        // Find the excerpt and buffer offset where the given range ends.
3863        cursor.seek(&query_range.end);
3864        let mut range_end = None;
3865        while let Some(region) = cursor.region() {
3866            if region.is_main_buffer {
3867                let mut buffer_end = region.buffer_range.start;
3868                let overshoot = if query_range.end > region.range.start {
3869                    query_range.end - region.range.start
3870                } else {
3871                    <MBD::TextDimension>::default()
3872                };
3873                buffer_end = buffer_end + overshoot;
3874                range_end = Some((region.excerpt, buffer_end));
3875                break;
3876            }
3877            cursor.next();
3878        }
3879
3880        cursor.seek(&query_range.start);
3881
3882        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3883            && region.range.start > MBD::default()
3884        {
3885            cursor.prev()
3886        } else if let Some(region) = cursor.region()
3887            && region.is_main_buffer
3888            && region.diff_hunk_status.is_some()
3889        {
3890            cursor.prev();
3891            if cursor.region().is_none_or(|region| region.is_main_buffer) {
3892                cursor.next();
3893            }
3894        }
3895
3896        iter::from_fn(move || {
3897            loop {
3898                let excerpt = cursor.excerpt()?;
3899
3900                // If we have already retrieved metadata for this excerpt, continue to use it.
3901                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3902                    .as_mut()
3903                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3904                {
3905                    Some(metadata)
3906                }
3907                // Otherwise, compute the intersection of the input range with the excerpt's range,
3908                // and retrieve the metadata for the resulting range.
3909                else {
3910                    let region = cursor.region()?;
3911                    let mut buffer_start;
3912                    if region.is_main_buffer {
3913                        buffer_start = region.buffer_range.start;
3914                        if query_range.start > region.range.start {
3915                            let overshoot = query_range.start - region.range.start;
3916                            buffer_start = buffer_start + overshoot;
3917                        }
3918                        buffer_start = buffer_start.min(region.buffer_range.end);
3919                    } else {
3920                        buffer_start = cursor.main_buffer_position()?;
3921                    };
3922                    let mut buffer_end = excerpt
3923                        .range
3924                        .context
3925                        .end
3926                        .summary::<MBD::TextDimension>(&excerpt.buffer);
3927                    if let Some((end_excerpt, end_buffer_offset)) = range_end
3928                        && excerpt == end_excerpt
3929                    {
3930                        buffer_end = buffer_end.min(end_buffer_offset);
3931                    }
3932
3933                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3934                        .map(|iterator| &mut current_excerpt_metadata.insert((excerpt, iterator)).1)
3935                };
3936
3937                // Visit each metadata item.
3938                if let Some((metadata_buffer_range, metadata)) =
3939                    metadata_iter.and_then(Iterator::next)
3940                {
3941                    // Find the multibuffer regions that contain the start and end of
3942                    // the metadata item's range.
3943                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3944                        while let Some(region) = cursor.region() {
3945                            if (region.is_main_buffer
3946                                && (region.buffer_range.end >= metadata_buffer_range.start
3947                                    || cursor.is_at_end_of_excerpt()))
3948                                || (!region.is_main_buffer
3949                                    && region.buffer_range.start == metadata_buffer_range.start)
3950                            {
3951                                break;
3952                            }
3953                            cursor.next();
3954                        }
3955                    }
3956                    let start_region = cursor.region()?.clone();
3957                    while let Some(region) = cursor.region() {
3958                        if region.is_main_buffer
3959                            && (region.buffer_range.end > metadata_buffer_range.end
3960                                || cursor.is_at_end_of_excerpt())
3961                        {
3962                            break;
3963                        }
3964                        cursor.next();
3965                    }
3966                    let end_region = cursor.region();
3967
3968                    // Convert the metadata item's range into multibuffer coordinates.
3969                    let mut start_position = start_region.range.start;
3970                    let region_buffer_start = start_region.buffer_range.start;
3971                    if start_region.is_main_buffer
3972                        && metadata_buffer_range.start > region_buffer_start
3973                    {
3974                        start_position =
3975                            start_position + (metadata_buffer_range.start - region_buffer_start);
3976                        start_position = start_position.min(start_region.range.end);
3977                    }
3978
3979                    let mut end_position = self.max_position();
3980                    if let Some(end_region) = &end_region {
3981                        end_position = end_region.range.start;
3982                        debug_assert!(end_region.is_main_buffer);
3983                        let region_buffer_start = end_region.buffer_range.start;
3984                        if metadata_buffer_range.end > region_buffer_start {
3985                            end_position =
3986                                end_position + (metadata_buffer_range.end - region_buffer_start);
3987                        }
3988                        end_position = end_position.min(end_region.range.end);
3989                    }
3990
3991                    if start_position <= query_range.end && end_position >= query_range.start {
3992                        return Some((start_position..end_position, metadata, excerpt));
3993                    }
3994                }
3995                // When there are no more metadata items for this excerpt, move to the next excerpt.
3996                else {
3997                    current_excerpt_metadata.take();
3998                    if let Some((end_excerpt, _)) = range_end
3999                        && excerpt == end_excerpt
4000                    {
4001                        return None;
4002                    }
4003                    cursor.next_excerpt_forwards();
4004                }
4005            }
4006        })
4007    }
4008
4009    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4010        let offset = position.to_offset(self);
4011
4012        let mut cursor = self
4013            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4014            );
4015        cursor.seek(&DimensionPair {
4016            key: offset,
4017            value: None,
4018        });
4019        cursor.seek_to_start_of_current_excerpt();
4020        let excerpt = cursor.excerpt()?;
4021
4022        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4023        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4024        let current_position = match self.anchor_before(offset) {
4025            Anchor::Min => 0,
4026            Anchor::Excerpt(excerpt_anchor) => {
4027                excerpt_anchor.text_anchor().to_offset(&excerpt.buffer)
4028            }
4029            Anchor::Max => unreachable!(),
4030        };
4031
4032        if let Some(diff) = self.diffs.get(&excerpt.buffer.remote_id()) {
4033            if let Some(main_buffer) = &diff.main_buffer {
4034                for hunk in diff
4035                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4036                {
4037                    if hunk.diff_base_byte_range.end >= current_position {
4038                        continue;
4039                    }
4040                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4041                    let start =
4042                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4043                    return Some(MultiBufferRow(start.row));
4044                }
4045            } else {
4046                let excerpt_end = excerpt
4047                    .buffer
4048                    .anchor_before(excerpt_end.min(current_position));
4049                for hunk in diff.hunks_intersecting_range_rev(
4050                    excerpt.range.context.start..excerpt_end,
4051                    &excerpt.buffer,
4052                ) {
4053                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4054                    if hunk_end >= current_position {
4055                        continue;
4056                    }
4057                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4058                        .to_point(self);
4059                    return Some(MultiBufferRow(start.row));
4060                }
4061            }
4062        }
4063
4064        loop {
4065            cursor.prev_excerpt();
4066            let excerpt = cursor.excerpt()?;
4067
4068            let Some(diff) = self.diffs.get(&excerpt.buffer.remote_id()) else {
4069                continue;
4070            };
4071            if let Some(main_buffer) = &diff.main_buffer {
4072                let Some(hunk) = diff
4073                    .hunks_intersecting_base_text_range_rev(
4074                        excerpt.range.context.to_offset(&excerpt.buffer),
4075                        main_buffer,
4076                    )
4077                    .next()
4078                else {
4079                    continue;
4080                };
4081                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4082                let start = Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4083                return Some(MultiBufferRow(start.row));
4084            } else {
4085                let Some(hunk) = diff
4086                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4087                    .next()
4088                else {
4089                    continue;
4090                };
4091                let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4092                    .to_point(self);
4093                return Some(MultiBufferRow(start.row));
4094            }
4095        }
4096    }
4097
4098    pub fn has_diff_hunks(&self) -> bool {
4099        self.diffs.values().any(|diff| !diff.is_empty())
4100    }
4101
4102    pub fn is_inside_word<T: ToOffset>(
4103        &self,
4104        position: T,
4105        scope_context: Option<CharScopeContext>,
4106    ) -> bool {
4107        let position = position.to_offset(self);
4108        let classifier = self
4109            .char_classifier_at(position)
4110            .scope_context(scope_context);
4111        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4112        let prev_char_kind = self
4113            .reversed_chars_at(position)
4114            .next()
4115            .map(|c| classifier.kind(c));
4116        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4117    }
4118
4119    pub fn surrounding_word<T: ToOffset>(
4120        &self,
4121        start: T,
4122        scope_context: Option<CharScopeContext>,
4123    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4124        let mut start = start.to_offset(self);
4125        let mut end = start;
4126        let mut next_chars = self.chars_at(start).peekable();
4127        let mut prev_chars = self.reversed_chars_at(start).peekable();
4128
4129        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4130
4131        let word_kind = cmp::max(
4132            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4133            next_chars.peek().copied().map(|c| classifier.kind(c)),
4134        );
4135
4136        for ch in prev_chars {
4137            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4138                start -= ch.len_utf8();
4139            } else {
4140                break;
4141            }
4142        }
4143
4144        for ch in next_chars {
4145            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4146                end += ch.len_utf8();
4147            } else {
4148                break;
4149            }
4150        }
4151
4152        (start..end, word_kind)
4153    }
4154
4155    pub fn char_kind_before<T: ToOffset>(
4156        &self,
4157        start: T,
4158        scope_context: Option<CharScopeContext>,
4159    ) -> Option<CharKind> {
4160        let start = start.to_offset(self);
4161        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4162        self.reversed_chars_at(start)
4163            .next()
4164            .map(|ch| classifier.kind(ch))
4165    }
4166
4167    pub fn is_singleton(&self) -> bool {
4168        self.singleton
4169    }
4170
4171    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4172        if self.singleton {
4173            self.excerpts
4174                .iter()
4175                .next()
4176                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4177        } else {
4178            None
4179        }
4180    }
4181
4182    pub fn len(&self) -> MultiBufferOffset {
4183        self.diff_transforms.summary().output.len
4184    }
4185
4186    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4187        MBD::from_summary(&self.text_summary())
4188    }
4189
4190    pub fn is_empty(&self) -> bool {
4191        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4192    }
4193
4194    pub fn widest_line_number(&self) -> u32 {
4195        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4196        self.excerpts.summary().widest_line_number + 1
4197    }
4198
4199    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4200        let range = range.start.to_offset(self)..range.end.to_offset(self);
4201        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4202        excerpts.seek(&range.start);
4203
4204        let mut chunk;
4205        let mut has_trailing_newline;
4206        let excerpt_bytes;
4207        if let Some(region) = excerpts.region() {
4208            let mut bytes = region.buffer.bytes_in_range(
4209                region.buffer_range.start + (range.start - region.range.start)
4210                    ..(region.buffer_range.start + (range.end - region.range.start))
4211                        .min(region.buffer_range.end),
4212            );
4213            chunk = bytes.next().unwrap_or(&[][..]);
4214            excerpt_bytes = Some(bytes);
4215            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4216            if chunk.is_empty() && has_trailing_newline {
4217                chunk = b"\n";
4218                has_trailing_newline = false;
4219            }
4220        } else {
4221            chunk = &[][..];
4222            excerpt_bytes = None;
4223            has_trailing_newline = false;
4224        };
4225
4226        MultiBufferBytes {
4227            range,
4228            cursor: excerpts,
4229            excerpt_bytes,
4230            has_trailing_newline,
4231            chunk,
4232        }
4233    }
4234
4235    pub fn reversed_bytes_in_range<T: ToOffset>(
4236        &self,
4237        range: Range<T>,
4238    ) -> ReversedMultiBufferBytes<'_> {
4239        let range = range.start.to_offset(self)..range.end.to_offset(self);
4240        let mut chunks = self.reversed_chunks_in_range(range.clone());
4241        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4242        ReversedMultiBufferBytes {
4243            range,
4244            chunks,
4245            chunk,
4246        }
4247    }
4248
4249    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4250        let mut cursor = self.cursor::<Point, Point>();
4251        cursor.seek(&Point::new(start_row.0, 0));
4252        let mut result = MultiBufferRows {
4253            point: Point::new(0, 0),
4254            is_empty: self.excerpts.is_empty(),
4255            is_singleton: self.is_singleton(),
4256            cursor,
4257        };
4258        result.seek(start_row);
4259        result
4260    }
4261
4262    pub fn chunks<T: ToOffset>(
4263        &self,
4264        range: Range<T>,
4265        language_aware: bool,
4266    ) -> MultiBufferChunks<'_> {
4267        let mut chunks = MultiBufferChunks {
4268            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4269                ..ExcerptDimension(MultiBufferOffset::ZERO),
4270            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4271            excerpts: self.excerpts.cursor(()),
4272            diff_transforms: self.diff_transforms.cursor(()),
4273            diffs: &self.diffs,
4274            diff_base_chunks: None,
4275            excerpt_chunks: None,
4276            buffer_chunk: None,
4277            language_aware,
4278        };
4279        let range = range.start.to_offset(self)..range.end.to_offset(self);
4280        chunks.seek(range);
4281        chunks
4282    }
4283
4284    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4285        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4286    }
4287
4288    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4289        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4290    }
4291
4292    pub fn clip_offset_utf16(
4293        &self,
4294        offset: MultiBufferOffsetUtf16,
4295        bias: Bias,
4296    ) -> MultiBufferOffsetUtf16 {
4297        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4298    }
4299
4300    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4301        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4302            buffer.clip_point_utf16(Unclipped(point), bias)
4303        })
4304    }
4305
4306    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4307        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4308    }
4309
4310    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4311        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4312    }
4313
4314    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4315        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4316    }
4317
4318    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4319        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4320    }
4321
4322    #[instrument(skip_all)]
4323    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4324        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4325    }
4326
4327    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4328        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4329    }
4330
4331    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4332        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4333    }
4334
4335    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4336        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4337    }
4338
4339    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4340        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4341    }
4342
4343    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4344        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4345    }
4346
4347    fn clip_dimension<MBD, BD>(
4348        &self,
4349        position: MBD,
4350        bias: Bias,
4351        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4352    ) -> MBD
4353    where
4354        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4355        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4356    {
4357        let mut cursor = self.cursor::<MBD, BD>();
4358        cursor.seek(&position);
4359        if let Some(region) = cursor.region() {
4360            if position >= region.range.end {
4361                return region.range.end;
4362            }
4363            let overshoot = position - region.range.start;
4364            let mut buffer_position = region.buffer_range.start;
4365            buffer_position += overshoot;
4366            let clipped_buffer_position =
4367                clip_buffer_position(region.buffer, buffer_position, bias);
4368            let mut position = region.range.start;
4369            position += clipped_buffer_position - region.buffer_range.start;
4370            position
4371        } else {
4372            self.max_position()
4373        }
4374    }
4375
4376    #[instrument(skip_all)]
4377    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4378        &self,
4379        key: MBR1,
4380        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4381    ) -> MBR2
4382    where
4383        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4384        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4385        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4386        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4387    {
4388        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4389        cursor.seek(&DimensionPair { key, value: None });
4390        if let Some(region) = cursor.region() {
4391            if key >= region.range.end.key {
4392                return region.range.end.value.unwrap();
4393            }
4394            let start_key = region.range.start.key;
4395            let start_value = region.range.start.value.unwrap();
4396            let buffer_start_key = region.buffer_range.start.key;
4397            let buffer_start_value = region.buffer_range.start.value.unwrap();
4398            let mut buffer_key = buffer_start_key;
4399            buffer_key += key - start_key;
4400            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4401            let mut result = start_value;
4402            result += buffer_value - buffer_start_value;
4403            result
4404        } else {
4405            self.max_position()
4406        }
4407    }
4408
4409    pub fn point_to_buffer_offset<T: ToOffset>(
4410        &self,
4411        point: T,
4412    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4413        let offset = point.to_offset(self);
4414        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4415        cursor.seek(&offset);
4416        let region = cursor.region()?;
4417        let overshoot = offset - region.range.start;
4418        let buffer_offset = region.buffer_range.start + overshoot;
4419        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4420            && region.has_trailing_newline
4421            && !region.is_main_buffer
4422        {
4423            let main_buffer_position = cursor.main_buffer_position()?;
4424            let buffer_snapshot = &cursor.excerpt()?.buffer;
4425            return Some((buffer_snapshot, main_buffer_position));
4426        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4427            return None;
4428        }
4429        Some((region.buffer, buffer_offset))
4430    }
4431
4432    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4433        let mut cursor = self.cursor::<Point, Point>();
4434        cursor.seek(&point);
4435        let region = cursor.region()?;
4436        let overshoot = point - region.range.start;
4437        let buffer_point = region.buffer_range.start + overshoot;
4438        let excerpt = cursor.excerpt()?;
4439        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4440            && region.has_trailing_newline
4441            && !region.is_main_buffer
4442        {
4443            return Some((&excerpt.buffer, cursor.main_buffer_position()?));
4444        } else if buffer_point > region.buffer.max_point() {
4445            return None;
4446        }
4447        Some((region.buffer, buffer_point))
4448    }
4449
4450    pub fn suggested_indents(
4451        &self,
4452        rows: impl IntoIterator<Item = u32>,
4453        cx: &App,
4454    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4455        let mut result = BTreeMap::new();
4456        self.suggested_indents_callback(
4457            rows,
4458            &mut |row, indent| {
4459                result.insert(row, indent);
4460                ControlFlow::Continue(())
4461            },
4462            cx,
4463        );
4464        result
4465    }
4466
4467    // move this to be a generator once those are a thing
4468    pub fn suggested_indents_callback(
4469        &self,
4470        rows: impl IntoIterator<Item = u32>,
4471        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4472        cx: &App,
4473    ) {
4474        let mut rows_for_excerpt = Vec::new();
4475        let mut cursor = self.cursor::<Point, Point>();
4476        let mut rows = rows.into_iter().peekable();
4477        let mut prev_row = u32::MAX;
4478        let mut prev_language_indent_size = IndentSize::default();
4479
4480        while let Some(row) = rows.next() {
4481            cursor.seek(&Point::new(row, 0));
4482            let Some(region) = cursor.region() else {
4483                continue;
4484            };
4485
4486            // Retrieve the language and indent size once for each disjoint region being indented.
4487            let single_indent_size = if row.saturating_sub(1) == prev_row {
4488                prev_language_indent_size
4489            } else {
4490                region
4491                    .buffer
4492                    .language_indent_size_at(Point::new(row, 0), cx)
4493            };
4494            prev_language_indent_size = single_indent_size;
4495            prev_row = row;
4496
4497            let start_buffer_row = region.buffer_range.start.row;
4498            let start_multibuffer_row = region.range.start.row;
4499            let end_multibuffer_row = region.range.end.row;
4500
4501            rows_for_excerpt.push(row);
4502            while let Some(next_row) = rows.peek().copied() {
4503                if end_multibuffer_row > next_row {
4504                    rows_for_excerpt.push(next_row);
4505                    rows.next();
4506                } else {
4507                    break;
4508                }
4509            }
4510
4511            let buffer_rows = rows_for_excerpt
4512                .drain(..)
4513                .map(|row| start_buffer_row + row - start_multibuffer_row);
4514            let buffer_indents = region
4515                .buffer
4516                .suggested_indents(buffer_rows, single_indent_size);
4517            for (row, indent) in buffer_indents {
4518                if cb(
4519                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4520                    indent,
4521                )
4522                .is_break()
4523                {
4524                    return;
4525                }
4526            }
4527        }
4528    }
4529
4530    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4531        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4532            let mut size = buffer.indent_size_for_line(range.start.row);
4533            size.len = size
4534                .len
4535                .min(range.end.column)
4536                .saturating_sub(range.start.column);
4537            size
4538        } else {
4539            IndentSize::spaces(0)
4540        }
4541    }
4542
4543    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4544        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4545            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4546        } else {
4547            LineIndent::spaces(0)
4548        }
4549    }
4550
4551    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4552        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4553
4554        if self.language_settings(cx).extend_comment_on_newline
4555            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4556        {
4557            let delimiters = language_scope.line_comment_prefixes();
4558            for delimiter in delimiters {
4559                if *self
4560                    .chars_at(Point::new(row.0, indent.len() as u32))
4561                    .take(delimiter.chars().count())
4562                    .collect::<String>()
4563                    .as_str()
4564                    == **delimiter
4565                {
4566                    indent.push_str(delimiter);
4567                    break;
4568                }
4569            }
4570        }
4571
4572        indent
4573    }
4574
4575    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4576    where
4577        T: ToOffset,
4578    {
4579        for char in self.reversed_chars_at(position) {
4580            if !char.is_whitespace() {
4581                return false;
4582            }
4583            if char == '\n' {
4584                return true;
4585            }
4586        }
4587        true
4588    }
4589
4590    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4591        while row.0 > 0 {
4592            row.0 -= 1;
4593            if !self.is_line_blank(row) {
4594                return Some(row);
4595            }
4596        }
4597        None
4598    }
4599
4600    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4601        if let Some((_, range)) = self.buffer_line_for_row(row) {
4602            range.end.column - range.start.column
4603        } else {
4604            0
4605        }
4606    }
4607
4608    pub fn buffer_line_for_row(
4609        &self,
4610        row: MultiBufferRow,
4611    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4612        let mut cursor = self.cursor::<Point, Point>();
4613        let point = Point::new(row.0, 0);
4614        cursor.seek(&point);
4615        let region = cursor.region()?;
4616        let overshoot = point.min(region.range.end) - region.range.start;
4617        let buffer_point = region.buffer_range.start + overshoot;
4618        if buffer_point.row > region.buffer_range.end.row {
4619            return None;
4620        }
4621        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4622        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4623            .min(region.buffer_range.end);
4624        Some((region.buffer, line_start..line_end))
4625    }
4626
4627    pub fn max_point(&self) -> Point {
4628        self.text_summary().lines
4629    }
4630
4631    pub fn max_row(&self) -> MultiBufferRow {
4632        MultiBufferRow(self.text_summary().lines.row)
4633    }
4634
4635    pub fn text_summary(&self) -> MBTextSummary {
4636        self.diff_transforms.summary().output
4637    }
4638
4639    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4640    where
4641        MBD: MultiBufferDimension + AddAssign,
4642        O: ToOffset,
4643    {
4644        let range = range.start.to_offset(self)..range.end.to_offset(self);
4645        let mut cursor = self
4646            .diff_transforms
4647            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4648        cursor.seek(&range.start, Bias::Right);
4649
4650        let Some(first_transform) = cursor.item() else {
4651            return MBD::from_summary(&MBTextSummary::default());
4652        };
4653
4654        let diff_transform_start = cursor.start().0;
4655        let diff_transform_end = cursor.end().0;
4656        let diff_start = range.start;
4657        let start_overshoot = diff_start - diff_transform_start;
4658        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4659
4660        let mut result = match first_transform {
4661            DiffTransform::BufferContent { .. } => {
4662                let excerpt_start = cursor.start().1 + start_overshoot;
4663                let excerpt_end = cursor.start().1 + end_overshoot;
4664                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4665            }
4666            DiffTransform::DeletedHunk {
4667                buffer_id,
4668                base_text_byte_range,
4669                has_trailing_newline,
4670                ..
4671            } => {
4672                let buffer_start = base_text_byte_range.start + start_overshoot;
4673                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4674                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4675                    panic!("{:?} is in non-existent deleted hunk", range.start)
4676                };
4677
4678                let include_trailing_newline =
4679                    *has_trailing_newline && range.end >= diff_transform_end;
4680                if include_trailing_newline {
4681                    buffer_end -= 1;
4682                }
4683
4684                let mut summary = base_text
4685                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4686
4687                if include_trailing_newline {
4688                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4689                        &TextSummary::newline(),
4690                    ))
4691                }
4692
4693                let mut result = MBD::default();
4694                result.add_text_dim(&summary);
4695                result
4696            }
4697        };
4698        if range.end < diff_transform_end {
4699            return result;
4700        }
4701
4702        cursor.next();
4703        result.add_mb_text_summary(
4704            &cursor
4705                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4706                .0,
4707        );
4708
4709        let Some(last_transform) = cursor.item() else {
4710            return result;
4711        };
4712
4713        let overshoot = range.end - cursor.start().0;
4714        let suffix = match last_transform {
4715            DiffTransform::BufferContent { .. } => {
4716                let end = cursor.start().1 + overshoot;
4717                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4718            }
4719            DiffTransform::DeletedHunk {
4720                base_text_byte_range,
4721                buffer_id,
4722                has_trailing_newline,
4723                ..
4724            } => {
4725                let buffer_end = base_text_byte_range.start + overshoot;
4726                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4727                    panic!("{:?} is in non-existent deleted hunk", range.end)
4728                };
4729
4730                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4731                    base_text_byte_range.start..buffer_end,
4732                );
4733                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4734                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4735                        &TextSummary::from("\n"),
4736                    ))
4737                }
4738
4739                let mut result = MBD::default();
4740                result.add_text_dim(&suffix);
4741                result
4742            }
4743        };
4744
4745        result += suffix;
4746        result
4747    }
4748
4749    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4750    where
4751        MBD: MultiBufferDimension + AddAssign,
4752    {
4753        let mut summary = MBD::default();
4754        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4755        cursor.seek(&range.start, Bias::Right);
4756        if let Some(excerpt) = cursor.item() {
4757            let mut end_before_newline = cursor.end();
4758            if excerpt.has_trailing_newline {
4759                end_before_newline -= 1;
4760            }
4761
4762            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4763            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4764            let end_in_excerpt =
4765                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4766            summary.add_text_dim(
4767                &excerpt
4768                    .buffer
4769                    .text_summary_for_range::<MBD::TextDimension, _>(
4770                        start_in_excerpt..end_in_excerpt,
4771                    ),
4772            );
4773
4774            if range.end > end_before_newline {
4775                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4776            }
4777
4778            cursor.next();
4779        }
4780
4781        if range.end > *cursor.start() {
4782            summary += cursor
4783                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4784                .0;
4785            if let Some(excerpt) = cursor.item() {
4786                range.end = cmp::max(*cursor.start(), range.end);
4787
4788                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4789                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4790                summary.add_text_dim(
4791                    &excerpt
4792                        .buffer
4793                        .text_summary_for_range::<MBD::TextDimension, _>(
4794                            excerpt_start..end_in_excerpt,
4795                        ),
4796                );
4797            }
4798        }
4799
4800        summary
4801    }
4802
4803    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4804    where
4805        MBD: MultiBufferDimension
4806            + Ord
4807            + Sub<Output = MBD::TextDimension>
4808            + Sub<MBD::TextDimension, Output = MBD>
4809            + AddAssign<MBD::TextDimension>
4810            + Add<MBD::TextDimension, Output = MBD>,
4811        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4812    {
4813        let target = anchor.seek_target(self);
4814        let anchor = match anchor {
4815            Anchor::Min => {
4816                return MBD::default();
4817            }
4818            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4819            Anchor::Max => {
4820                return MBD::from_summary(&self.text_summary());
4821            }
4822        };
4823
4824        let (start, _, item) = self
4825            .excerpts
4826            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4827        let start = MBD::from_summary(&start.text);
4828
4829        let excerpt_start_position = ExcerptDimension(start);
4830        if self.diff_transforms.is_empty() {
4831            if let Some(excerpt) = item {
4832                if !excerpt.contains(anchor) {
4833                    return excerpt_start_position.0;
4834                }
4835                let excerpt_buffer_start = excerpt
4836                    .range
4837                    .context
4838                    .start
4839                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4840                let excerpt_buffer_end = excerpt
4841                    .range
4842                    .context
4843                    .end
4844                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4845                let buffer_summary = anchor
4846                    .text_anchor()
4847                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4848                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4849                let mut position = excerpt_start_position;
4850                if summary > excerpt_buffer_start {
4851                    position += summary - excerpt_buffer_start;
4852                }
4853
4854                position.0
4855            } else {
4856                excerpt_start_position.0
4857            }
4858        } else {
4859            let mut diff_transforms_cursor = self
4860                .diff_transforms
4861                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4862            diff_transforms_cursor.next();
4863
4864            if let Some(excerpt) = item {
4865                if !excerpt.contains(anchor) {
4866                    return self.summary_for_excerpt_position_without_hunks(
4867                        Bias::Left,
4868                        excerpt_start_position,
4869                        &mut diff_transforms_cursor,
4870                    );
4871                }
4872                let excerpt_buffer_start = excerpt
4873                    .range
4874                    .context
4875                    .start
4876                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4877                let excerpt_buffer_end = excerpt
4878                    .range
4879                    .context
4880                    .end
4881                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4882                let buffer_summary = anchor
4883                    .text_anchor()
4884                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4885                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4886                let mut position = excerpt_start_position;
4887                if summary > excerpt_buffer_start {
4888                    position += summary - excerpt_buffer_start;
4889                }
4890
4891                if diff_transforms_cursor.start().0 < position {
4892                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
4893                }
4894                self.summary_for_anchor_with_excerpt_position(
4895                    *anchor,
4896                    position,
4897                    &mut diff_transforms_cursor,
4898                    &excerpt.buffer,
4899                )
4900            } else {
4901                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
4902                self.summary_for_excerpt_position_without_hunks(
4903                    Bias::Right,
4904                    excerpt_start_position,
4905                    &mut diff_transforms_cursor,
4906                )
4907            }
4908        }
4909    }
4910
4911    /// Maps an anchor's excerpt-space position to its output-space position by
4912    /// walking the diff transforms. The cursor is shared across consecutive
4913    /// calls, so it may already be partway through the transform list.
4914    fn summary_for_anchor_with_excerpt_position<MBD>(
4915        &self,
4916        anchor: ExcerptAnchor,
4917        excerpt_position: ExcerptDimension<MBD>,
4918        diff_transforms: &mut Cursor<
4919            DiffTransform,
4920            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4921        >,
4922        excerpt_buffer: &text::BufferSnapshot,
4923    ) -> MBD
4924    where
4925        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4926    {
4927        loop {
4928            let transform_end_position = diff_transforms.end().0;
4929            let item = diff_transforms.item();
4930            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4931
4932            // A right-biased anchor at a transform boundary belongs to the
4933            // *next* transform, so advance past the current one.
4934            if anchor.bias == Bias::Right && at_transform_end {
4935                diff_transforms.next();
4936                continue;
4937            }
4938
4939            let mut position = diff_transforms.start().1;
4940            match item {
4941                Some(DiffTransform::DeletedHunk {
4942                    buffer_id,
4943                    base_text_byte_range,
4944                    hunk_info,
4945                    ..
4946                }) => {
4947                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
4948                        && let Some(base_text) =
4949                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4950                        && diff_base_anchor.is_valid(&base_text)
4951                    {
4952                        // The anchor carries a diff-base position — resolve it
4953                        // to a location inside the deleted hunk.
4954                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4955                        if base_text_offset >= base_text_byte_range.start
4956                            && base_text_offset <= base_text_byte_range.end
4957                        {
4958                            let position_in_hunk = base_text
4959                                .text_summary_for_range::<MBD::TextDimension, _>(
4960                                    base_text_byte_range.start..base_text_offset,
4961                                );
4962                            position.0.add_text_dim(&position_in_hunk);
4963                        } else if at_transform_end {
4964                            // diff_base offset falls outside this hunk's range;
4965                            // advance to see if the next transform is a better fit.
4966                            diff_transforms.next();
4967                            continue;
4968                        }
4969                    } else if at_transform_end
4970                        && anchor
4971                            .text_anchor()
4972                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
4973                            .is_gt()
4974                    {
4975                        // The anchor has no (valid) diff-base position, so it
4976                        // belongs in the buffer content, not in the deleted
4977                        // hunk. However, after an edit deletes the text between
4978                        // the hunk boundary and this anchor, both resolve to
4979                        // the same excerpt_position—landing us here on the
4980                        // DeletedHunk left behind by the shared cursor. Use the
4981                        // CRDT ordering to detect that the anchor is strictly
4982                        // *past* the hunk boundary and skip to the following
4983                        // BufferContent.
4984                        diff_transforms.next();
4985                        continue;
4986                    }
4987                }
4988                _ => {
4989                    // On a BufferContent (or no transform). If the anchor
4990                    // carries a diff_base_anchor it needs a DeletedHunk, so
4991                    // advance to find one.
4992                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4993                        diff_transforms.next();
4994                        continue;
4995                    }
4996                    let overshoot = excerpt_position - diff_transforms.start().0;
4997                    position += overshoot;
4998                }
4999            }
5000
5001            return position.0;
5002        }
5003    }
5004
5005    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5006    fn summary_for_excerpt_position_without_hunks<MBD>(
5007        &self,
5008        bias: Bias,
5009        excerpt_position: ExcerptDimension<MBD>,
5010        diff_transforms: &mut Cursor<
5011            DiffTransform,
5012            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5013        >,
5014    ) -> MBD
5015    where
5016        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5017    {
5018        loop {
5019            let transform_end_position = diff_transforms.end().0;
5020            let item = diff_transforms.item();
5021            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5022
5023            // A right-biased anchor at a transform boundary belongs to the
5024            // *next* transform, so advance past the current one.
5025            if bias == Bias::Right && at_transform_end {
5026                diff_transforms.next();
5027                continue;
5028            }
5029
5030            let mut position = diff_transforms.start().1;
5031            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5032                let overshoot = excerpt_position - diff_transforms.start().0;
5033                position += overshoot;
5034            }
5035
5036            return position.0;
5037        }
5038    }
5039
5040    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5041        let anchor = match anchor {
5042            Anchor::Min => return ExcerptOffset::default(),
5043            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5044            Anchor::Max => return self.excerpts.summary().len(),
5045        };
5046        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5047        let target = anchor.seek_target(self);
5048
5049        cursor.seek(&target, Bias::Left);
5050
5051        let mut position = cursor.start().len();
5052        if let Some(excerpt) = cursor.item()
5053            && excerpt.contains(anchor)
5054        {
5055            let excerpt_buffer_start = excerpt
5056                .buffer
5057                .offset_for_anchor(&excerpt.range.context.start);
5058            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5059            let buffer_position = cmp::min(
5060                excerpt_buffer_end,
5061                excerpt.buffer.offset_for_anchor(&anchor.text_anchor()),
5062            );
5063            if buffer_position > excerpt_buffer_start {
5064                position += buffer_position - excerpt_buffer_start;
5065            }
5066        }
5067        position
5068    }
5069
5070    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5071    where
5072        MBD: MultiBufferDimension
5073            + Ord
5074            + Sub<Output = MBD::TextDimension>
5075            + AddAssign<MBD::TextDimension>,
5076        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5077        I: 'a + IntoIterator<Item = &'a Anchor>,
5078    {
5079        let mut anchors = anchors.into_iter().peekable();
5080        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5081        let mut diff_transforms_cursor = self
5082            .diff_transforms
5083            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5084        diff_transforms_cursor.next();
5085
5086        let mut summaries = Vec::new();
5087        while let Some(anchor) = anchors.peek() {
5088            let target = anchor.seek_target(self);
5089            let excerpt_anchor = match anchor {
5090                Anchor::Min => {
5091                    summaries.push(MBD::default());
5092                    anchors.next();
5093                    continue;
5094                }
5095                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5096                Anchor::Max => {
5097                    summaries.push(MBD::from_summary(&self.text_summary()));
5098                    anchors.next();
5099                    continue;
5100                }
5101            };
5102
5103            cursor.seek_forward(&target, Bias::Left);
5104
5105            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5106            if let Some(excerpt) = cursor.item() {
5107                if !excerpt.contains(&excerpt_anchor) {
5108                    let position = self.summary_for_excerpt_position_without_hunks(
5109                        Bias::Left,
5110                        excerpt_start_position,
5111                        &mut diff_transforms_cursor,
5112                    );
5113                    summaries.push(position);
5114                    anchors.next();
5115                    continue;
5116                }
5117                let excerpt_buffer_start = excerpt
5118                    .range
5119                    .context
5120                    .start
5121                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5122                let excerpt_buffer_end = excerpt
5123                    .range
5124                    .context
5125                    .end
5126                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5127                for (buffer_summary, excerpt_anchor) in excerpt
5128                    .buffer
5129                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5130                        std::iter::from_fn(|| {
5131                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5132                            if !excerpt.contains(&excerpt_anchor) {
5133                                return None;
5134                            }
5135                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5136                        }),
5137                    )
5138                {
5139                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5140                    let mut position = excerpt_start_position;
5141                    if summary > excerpt_buffer_start {
5142                        position += summary - excerpt_buffer_start;
5143                    }
5144
5145                    if diff_transforms_cursor.start().0 < position {
5146                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5147                    }
5148
5149                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5150                        excerpt_anchor,
5151                        position,
5152                        &mut diff_transforms_cursor,
5153                        &excerpt.buffer,
5154                    ));
5155                }
5156            } else {
5157                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5158                let position = self.summary_for_excerpt_position_without_hunks(
5159                    Bias::Right,
5160                    excerpt_start_position,
5161                    &mut diff_transforms_cursor,
5162                );
5163                summaries.push(position);
5164                anchors.next();
5165            }
5166        }
5167
5168        summaries
5169    }
5170
5171    pub fn dimensions_from_points<'a, MBD>(
5172        &'a self,
5173        points: impl 'a + IntoIterator<Item = Point>,
5174    ) -> impl 'a + Iterator<Item = MBD>
5175    where
5176        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5177    {
5178        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5179        cursor.seek(&DimensionPair {
5180            key: Point::default(),
5181            value: None,
5182        });
5183        let mut points = points.into_iter();
5184        iter::from_fn(move || {
5185            let point = points.next()?;
5186
5187            cursor.seek_forward(&DimensionPair {
5188                key: point,
5189                value: None,
5190            });
5191
5192            if let Some(region) = cursor.region() {
5193                let overshoot = point - region.range.start.key;
5194                let buffer_point = region.buffer_range.start + overshoot;
5195                let mut position = region.range.start.value.unwrap();
5196                position.add_text_dim(
5197                    &region
5198                        .buffer
5199                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5200                );
5201                if point == region.range.end.key && region.has_trailing_newline {
5202                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5203                }
5204                Some(position)
5205            } else {
5206                Some(MBD::from_summary(&self.text_summary()))
5207            }
5208        })
5209    }
5210
5211    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5212    where
5213        I: 'a + IntoIterator<Item = &'a Anchor>,
5214    {
5215        let mut anchors = anchors.into_iter().enumerate().peekable();
5216        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5217        cursor.next();
5218
5219        let mut result = Vec::new();
5220
5221        while let Some((_, anchor)) = anchors.peek() {
5222            let old_excerpt_id = anchor.excerpt_id;
5223
5224            // Find the location where this anchor's excerpt should be.
5225            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5226            cursor.seek_forward(&Some(old_locator), Bias::Left);
5227
5228            let next_excerpt = cursor.item();
5229            let prev_excerpt = cursor.prev_item();
5230
5231            // Process all of the anchors for this excerpt.
5232            while let Some((anchor_ix, &anchor)) =
5233                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5234            {
5235                let mut anchor = anchor;
5236
5237                // Leave min and max anchors unchanged if invalid or
5238                // if the old excerpt still exists at this location
5239                let mut kept_position = next_excerpt
5240                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5241                    || old_excerpt_id == ExcerptId::max()
5242                    || old_excerpt_id == ExcerptId::min();
5243
5244                // If the old excerpt no longer exists at this location, then attempt to
5245                // find an equivalent position for this anchor in an adjacent excerpt.
5246                if !kept_position {
5247                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5248                        if excerpt.contains(&anchor) {
5249                            anchor.excerpt_id = excerpt.id;
5250                            kept_position = true;
5251                            break;
5252                        }
5253                    }
5254                }
5255
5256                // If there's no adjacent excerpt that contains the anchor's position,
5257                // then report that the anchor has lost its position.
5258                if !kept_position {
5259                    anchor = if let Some(excerpt) = next_excerpt {
5260                        let mut text_anchor = excerpt
5261                            .range
5262                            .context
5263                            .start
5264                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5265                        if text_anchor
5266                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5267                            .is_gt()
5268                        {
5269                            text_anchor = excerpt.range.context.end;
5270                        }
5271                        Anchor::text(excerpt.id, text_anchor)
5272                    } else if let Some(excerpt) = prev_excerpt {
5273                        let mut text_anchor = excerpt
5274                            .range
5275                            .context
5276                            .end
5277                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5278                        if text_anchor
5279                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5280                            .is_lt()
5281                        {
5282                            text_anchor = excerpt.range.context.start;
5283                        }
5284                        Anchor::text(excerpt.id, text_anchor)
5285                    } else if anchor.text_anchor.bias == Bias::Left {
5286                        Anchor::min()
5287                    } else {
5288                        Anchor::max()
5289                    };
5290                }
5291
5292                result.push((anchor_ix, anchor, kept_position));
5293            }
5294        }
5295        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5296        result
5297    }
5298
5299    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5300        self.anchor_at(position, Bias::Left)
5301    }
5302
5303    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5304        self.anchor_at(position, Bias::Right)
5305    }
5306
5307    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5308        let offset = position.to_offset(self);
5309
5310        // Find the given position in the diff transforms. Determine the corresponding
5311        // offset in the excerpts, and whether the position is within a deleted hunk.
5312        let mut diff_transforms = self
5313            .diff_transforms
5314            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5315        diff_transforms.seek(&offset, Bias::Right);
5316
5317        if offset == diff_transforms.start().0
5318            && bias == Bias::Left
5319            && let Some(prev_item) = diff_transforms.prev_item()
5320            && let DiffTransform::DeletedHunk { .. } = prev_item
5321        {
5322            diff_transforms.prev();
5323        }
5324        let offset_in_transform = offset - diff_transforms.start().0;
5325        let mut excerpt_offset = diff_transforms.start().1;
5326        let mut diff_base_anchor = None;
5327        if let Some(DiffTransform::DeletedHunk {
5328            buffer_id,
5329            base_text_byte_range,
5330            has_trailing_newline,
5331            ..
5332        }) = diff_transforms.item()
5333        {
5334            let diff = self.diffs.get(buffer_id).expect("missing diff");
5335            if offset_in_transform > base_text_byte_range.len() {
5336                debug_assert!(*has_trailing_newline);
5337                bias = Bias::Right;
5338            } else {
5339                diff_base_anchor = Some(
5340                    diff.base_text()
5341                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5342                );
5343                bias = Bias::Left;
5344            }
5345        } else {
5346            excerpt_offset += MultiBufferOffset(offset_in_transform);
5347        };
5348
5349        let mut excerpts = self
5350            .excerpts
5351            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5352        excerpts.seek(&excerpt_offset, Bias::Right);
5353        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5354            excerpts.prev();
5355        }
5356        if let Some(excerpt) = excerpts.item() {
5357            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5358            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5359                overshoot -= 1;
5360                bias = Bias::Right;
5361            }
5362
5363            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5364            let text_anchor =
5365                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5366            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5367            let anchor = match diff_base_anchor {
5368                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5369                None => anchor,
5370            };
5371            anchor.into()
5372        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5373        {
5374            Anchor::min()
5375        } else {
5376            Anchor::max()
5377        }
5378    }
5379
5380    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5381    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5382        let (excerpt, buffer, _) = self.as_singleton()?;
5383        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5384            Some(Anchor::in_buffer(excerpt, text_anchor))
5385        } else {
5386            None
5387        }
5388    }
5389
5390    /// Returns an anchor for the given excerpt and text anchor,
5391    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5392    pub fn anchor_range_in_buffer(
5393        &self,
5394        excerpt_id: BufferId,
5395        text_anchor: Range<text::Anchor>,
5396    ) -> Option<Range<Anchor>> {
5397        let path_key_index = self.first_excerpt_for_buffer(buffer_id)?.path_key_index;
5398
5399        let target = self.anchor_see
5400        self.excerpts.cursor.find(&snapshot, (path_key_index, anchor))
5401
5402        Some(
5403            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5404                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5405        )
5406    }
5407
5408    /// Returns an anchor for the given excerpt and text anchor,
5409    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5410    pub fn anchor_in_excerpt(
5411        &self,
5412        excerpt_id: ExcerptId,
5413        text_anchor: text::Anchor,
5414    ) -> Option<Anchor> {
5415        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5416        Self::anchor_in_excerpt_(excerpt, text_anchor)
5417    }
5418
5419    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5420    pub fn anchors_in_excerpt(
5421        &self,
5422        excerpt_id: ExcerptId,
5423        text_anchors: impl IntoIterator<Item = text::Anchor>,
5424    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5425        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5426        Some(
5427            text_anchors
5428                .into_iter()
5429                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5430        )
5431    }
5432
5433    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5434        match text_anchor.buffer_id {
5435            Some(buffer_id) if buffer_id == excerpt.buffer.remote_id() => (),
5436            Some(_) => return None,
5437            None if text_anchor.is_max() || text_anchor.is_min() => {
5438                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5439            }
5440            None => return None,
5441        }
5442
5443        let context = &excerpt.range.context;
5444        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5445            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5446        {
5447            return None;
5448        }
5449
5450        Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor))
5451    }
5452
5453    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5454        match anchor {
5455            // todo(lw): should be `!self.is_empty()`
5456            Anchor::Min | Anchor::Max => true,
5457            Anchor::Excerpt(excerpt_anchor) => {
5458                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5459                    return false;
5460                };
5461                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5462                cursor.seek(&target, Bias::Left);
5463                let Some(excerpt) = cursor.item() else {
5464                    return false;
5465                };
5466                excerpt.buffer.can_resolve(&excerpt_anchor.text_anchor())
5467            }
5468        }
5469    }
5470
5471    pub fn excerpts(
5472        &self,
5473    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5474        self.excerpts
5475            .iter()
5476            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5477    }
5478
5479    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5480    where
5481        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5482        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5483    {
5484        let excerpts = self.excerpts.cursor(());
5485        let diff_transforms = self.diff_transforms.cursor(());
5486        MultiBufferCursor {
5487            excerpts,
5488            diff_transforms,
5489            diffs: &self.diffs,
5490            cached_region: OnceCell::new(),
5491        }
5492    }
5493
5494    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5495        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5496        let mut excerpts = self
5497            .excerpts
5498            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5499        excerpts.seek(&Some(start_locator), Bias::Left);
5500        excerpts.prev();
5501
5502        let mut diff_transforms = self
5503            .diff_transforms
5504            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5505        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5506        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5507            diff_transforms.next();
5508        }
5509
5510        let excerpt = excerpts.item()?;
5511        Some(MultiBufferExcerpt {
5512            excerpt,
5513            offset: diff_transforms.start().output_dimension.0,
5514            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5515            excerpt_offset: excerpts.start().1,
5516            diff_transforms,
5517        })
5518    }
5519
5520    pub fn excerpt_boundaries_in_range<R, T>(
5521        &self,
5522        range: R,
5523    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5524    where
5525        R: RangeBounds<T>,
5526        T: ToOffset,
5527    {
5528        let start_offset;
5529        let start = match range.start_bound() {
5530            Bound::Included(start) => {
5531                start_offset = start.to_offset(self);
5532                Bound::Included(start_offset)
5533            }
5534            Bound::Excluded(_) => {
5535                panic!("not supported")
5536            }
5537            Bound::Unbounded => {
5538                start_offset = MultiBufferOffset::ZERO;
5539                Bound::Unbounded
5540            }
5541        };
5542        let end = match range.end_bound() {
5543            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5544            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5545            Bound::Unbounded => Bound::Unbounded,
5546        };
5547        let bounds = (start, end);
5548        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5549        cursor.seek(&DimensionPair {
5550            key: start_offset,
5551            value: None,
5552        });
5553
5554        if cursor
5555            .fetch_excerpt_with_range()
5556            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5557        {
5558            cursor.prev_excerpt();
5559        } else {
5560            cursor.seek_to_start_of_current_excerpt();
5561        }
5562        let mut prev_region = cursor
5563            .fetch_excerpt_with_range()
5564            .map(|(excerpt, _)| excerpt);
5565
5566        cursor.next_excerpt_forwards();
5567
5568        iter::from_fn(move || {
5569            loop {
5570                if self.singleton {
5571                    return None;
5572                }
5573
5574                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5575                cursor.next_excerpt_forwards();
5576                if !bounds.contains(&next_range.start.key) {
5577                    prev_region = Some(next_excerpt);
5578                    continue;
5579                }
5580
5581                let next_region_start = next_range.start.value.unwrap();
5582                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5583                    range.start.value.unwrap()
5584                } else {
5585                    self.max_point()
5586                };
5587
5588                let prev = prev_region.as_ref().map(|region| ExcerptBoundaryInfo {
5589                    id: region.id,
5590                    buffer: region.buffer.clone(),
5591                    buffer_id: region.buffer_id,
5592                    range: region.range.clone(),
5593                    end_row: MultiBufferRow(next_region_start.row),
5594                });
5595
5596                let next = ExcerptBoundaryInfo {
5597                    id: next_excerpt.id,
5598                    buffer: next_excerpt.buffer.clone(),
5599                    buffer_id: next_excerpt.buffer_id,
5600                    range: next_excerpt.range.clone(),
5601                    end_row: if next_excerpt.has_trailing_newline {
5602                        MultiBufferRow(next_region_end.row - 1)
5603                    } else {
5604                        MultiBufferRow(next_region_end.row)
5605                    },
5606                };
5607
5608                let row = MultiBufferRow(next_region_start.row);
5609
5610                prev_region = Some(next_excerpt);
5611
5612                return Some(ExcerptBoundary { row, prev, next });
5613            }
5614        })
5615    }
5616
5617    pub fn edit_count(&self) -> usize {
5618        self.edit_count
5619    }
5620
5621    pub fn non_text_state_update_count(&self) -> usize {
5622        self.non_text_state_update_count
5623    }
5624
5625    /// Returns the smallest enclosing bracket ranges containing the given range or
5626    /// None if no brackets contain range or the range is not contained in a single
5627    /// excerpt
5628    ///
5629    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5630    #[ztracing::instrument(skip_all)]
5631    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5632        &self,
5633        range: Range<T>,
5634        range_filter: Option<
5635            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5636        >,
5637    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5638        let range = range.start.to_offset(self)..range.end.to_offset(self);
5639        let mut excerpt = self.excerpt_containing(range.clone())?;
5640        let buffer = excerpt.buffer();
5641        let excerpt_buffer_range = excerpt.buffer_range();
5642
5643        // Filter to ranges contained in the excerpt
5644        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5645            excerpt_buffer_range.contains(&BufferOffset(open.start))
5646                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5647                && range_filter.is_none_or(|filter| {
5648                    filter(
5649                        buffer,
5650                        BufferOffset(open.start)..BufferOffset(close.end),
5651                        BufferOffset(close.start)..BufferOffset(close.end),
5652                    )
5653                })
5654        };
5655
5656        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5657            excerpt.map_range_to_buffer(range),
5658            Some(&range_filter),
5659        )?;
5660
5661        Some((
5662            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5663            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5664        ))
5665    }
5666
5667    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5668    /// not contained in a single excerpt
5669    pub fn enclosing_bracket_ranges<T: ToOffset>(
5670        &self,
5671        range: Range<T>,
5672    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5673    {
5674        let range = range.start.to_offset(self)..range.end.to_offset(self);
5675        let mut excerpt = self.excerpt_containing(range.clone())?;
5676
5677        Some(
5678            excerpt
5679                .buffer()
5680                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5681                .filter_map(move |pair| {
5682                    let open_range =
5683                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5684                    let close_range =
5685                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5686                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5687                        Some((
5688                            excerpt.map_range_from_buffer(open_range),
5689                            excerpt.map_range_from_buffer(close_range),
5690                        ))
5691                    } else {
5692                        None
5693                    }
5694                }),
5695        )
5696    }
5697
5698    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5699    /// not contained in a single excerpt
5700    pub fn text_object_ranges<T: ToOffset>(
5701        &self,
5702        range: Range<T>,
5703        options: TreeSitterOptions,
5704    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5705        let range = range.start.to_offset(self)..range.end.to_offset(self);
5706        self.excerpt_containing(range.clone())
5707            .map(|mut excerpt| {
5708                excerpt
5709                    .buffer()
5710                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5711                    .filter_map(move |(range, text_object)| {
5712                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5713                        if excerpt.contains_buffer_range(range.clone()) {
5714                            Some((excerpt.map_range_from_buffer(range), text_object))
5715                        } else {
5716                            None
5717                        }
5718                    })
5719            })
5720            .into_iter()
5721            .flatten()
5722    }
5723
5724    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5725    /// not contained in a single excerpt
5726    pub fn bracket_ranges<T: ToOffset>(
5727        &self,
5728        range: Range<T>,
5729    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5730    {
5731        let range = range.start.to_offset(self)..range.end.to_offset(self);
5732        let mut excerpt = self.excerpt_containing(range.clone())?;
5733        Some(
5734            excerpt
5735                .buffer()
5736                .bracket_ranges(excerpt.map_range_to_buffer(range))
5737                .filter_map(move |pair| {
5738                    let open_range =
5739                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5740                    let close_range =
5741                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5742                    excerpt
5743                        .contains_buffer_range(open_range.start..close_range.end)
5744                        .then(|| BracketMatch {
5745                            open_range: excerpt.map_range_from_buffer(open_range),
5746                            close_range: excerpt.map_range_from_buffer(close_range),
5747                            color_index: pair.color_index,
5748                            newline_only: pair.newline_only,
5749                            syntax_layer_depth: pair.syntax_layer_depth,
5750                        })
5751                })
5752                .map(BracketMatch::bracket_ranges),
5753        )
5754    }
5755
5756    pub fn redacted_ranges<'a, T: ToOffset>(
5757        &'a self,
5758        range: Range<T>,
5759        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5760    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5761        let range = range.start.to_offset(self)..range.end.to_offset(self);
5762        self.lift_buffer_metadata(range, move |buffer, range| {
5763            if redaction_enabled(buffer.file()) {
5764                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5765            } else {
5766                None
5767            }
5768        })
5769        .map(|(range, _, _)| range)
5770    }
5771
5772    pub fn runnable_ranges(
5773        &self,
5774        range: Range<Anchor>,
5775    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5776        let range = range.start.to_offset(self)..range.end.to_offset(self);
5777        self.lift_buffer_metadata(range, move |buffer, range| {
5778            Some(
5779                buffer
5780                    .runnable_ranges(range.clone())
5781                    .filter(move |runnable| {
5782                        runnable.run_range.start >= range.start
5783                            && runnable.run_range.end < range.end
5784                    })
5785                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5786            )
5787        })
5788        .map(|(run_range, runnable, _)| (run_range, runnable))
5789    }
5790
5791    pub fn line_indents(
5792        &self,
5793        start_row: MultiBufferRow,
5794        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5795    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5796        let max_point = self.max_point();
5797        let mut cursor = self.cursor::<Point, Point>();
5798        cursor.seek(&Point::new(start_row.0, 0));
5799        iter::from_fn(move || {
5800            let mut region = cursor.region()?;
5801            while !buffer_filter(&region.excerpt.buffer) {
5802                cursor.next();
5803                region = cursor.region()?;
5804            }
5805            let region = cursor.region()?;
5806            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5807            let buffer_start_row =
5808                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5809
5810            let buffer_end_row = if region.is_main_buffer
5811                && (region.has_trailing_newline || region.range.end == max_point)
5812            {
5813                region.buffer_range.end.row
5814            } else {
5815                region.buffer_range.end.row.saturating_sub(1)
5816            };
5817
5818            let line_indents = region
5819                .buffer
5820                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5821            let region_buffer_row = region.buffer_range.start.row;
5822            let region_row = region.range.start.row;
5823            let region_buffer = &region.excerpt.buffer;
5824            cursor.next();
5825            Some(line_indents.map(move |(buffer_row, indent)| {
5826                let row = region_row + (buffer_row - region_buffer_row);
5827                (MultiBufferRow(row), indent, region_buffer.as_ref())
5828            }))
5829        })
5830        .flatten()
5831    }
5832
5833    pub fn reversed_line_indents(
5834        &self,
5835        end_row: MultiBufferRow,
5836        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5837    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5838        let max_point = self.max_point();
5839        let mut cursor = self.cursor::<Point, Point>();
5840        cursor.seek(&Point::new(end_row.0, 0));
5841        iter::from_fn(move || {
5842            let mut region = cursor.region()?;
5843            while !buffer_filter(&region.excerpt.buffer) {
5844                cursor.prev();
5845                region = cursor.region()?;
5846            }
5847            let region = cursor.region()?;
5848
5849            let buffer_start_row = region.buffer_range.start.row;
5850            let buffer_end_row = if region.is_main_buffer
5851                && (region.has_trailing_newline || region.range.end == max_point)
5852            {
5853                region.buffer_range.end.row + 1
5854            } else {
5855                region.buffer_range.end.row
5856            };
5857
5858            let overshoot = end_row.0 - region.range.start.row;
5859            let buffer_end_row =
5860                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5861
5862            let line_indents = region
5863                .buffer
5864                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5865            let region_buffer_row = region.buffer_range.start.row;
5866            let region_row = region.range.start.row;
5867            let region_buffer = &region.excerpt.buffer;
5868            cursor.prev();
5869            Some(line_indents.map(move |(buffer_row, indent)| {
5870                let row = region_row + (buffer_row - region_buffer_row);
5871                (MultiBufferRow(row), indent, region_buffer.as_ref())
5872            }))
5873        })
5874        .flatten()
5875    }
5876
5877    pub async fn enclosing_indent(
5878        &self,
5879        mut target_row: MultiBufferRow,
5880    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5881        let max_row = MultiBufferRow(self.max_point().row);
5882        if target_row >= max_row {
5883            return None;
5884        }
5885
5886        let mut target_indent = self.line_indent_for_row(target_row);
5887
5888        // If the current row is at the start of an indented block, we want to return this
5889        // block as the enclosing indent.
5890        if !target_indent.is_line_empty() && target_row < max_row {
5891            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5892            if !next_line_indent.is_line_empty()
5893                && target_indent.raw_len() < next_line_indent.raw_len()
5894            {
5895                target_indent = next_line_indent;
5896                target_row.0 += 1;
5897            }
5898        }
5899
5900        const SEARCH_ROW_LIMIT: u32 = 25000;
5901        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5902        const YIELD_INTERVAL: u32 = 100;
5903
5904        let mut accessed_row_counter = 0;
5905
5906        // If there is a blank line at the current row, search for the next non indented lines
5907        if target_indent.is_line_empty() {
5908            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5909            let end =
5910                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5911
5912            let mut non_empty_line_above = None;
5913            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5914                if row < start {
5915                    break;
5916                }
5917                accessed_row_counter += 1;
5918                if accessed_row_counter == YIELD_INTERVAL {
5919                    accessed_row_counter = 0;
5920                    yield_now().await;
5921                }
5922                if !indent.is_line_empty() {
5923                    non_empty_line_above = Some((row, indent));
5924                    break;
5925                }
5926            }
5927
5928            let mut non_empty_line_below = None;
5929            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5930                if row > end {
5931                    break;
5932                }
5933                accessed_row_counter += 1;
5934                if accessed_row_counter == YIELD_INTERVAL {
5935                    accessed_row_counter = 0;
5936                    yield_now().await;
5937                }
5938                if !indent.is_line_empty() {
5939                    non_empty_line_below = Some((row, indent));
5940                    break;
5941                }
5942            }
5943
5944            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5945                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5946                    if above_indent.raw_len() >= below_indent.raw_len() {
5947                        (above_row, above_indent)
5948                    } else {
5949                        (below_row, below_indent)
5950                    }
5951                }
5952                (Some(above), None) => above,
5953                (None, Some(below)) => below,
5954                _ => return None,
5955            };
5956
5957            target_indent = indent;
5958            target_row = row;
5959        }
5960
5961        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5962        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5963
5964        let mut start_indent = None;
5965        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5966            if row < start {
5967                break;
5968            }
5969            accessed_row_counter += 1;
5970            if accessed_row_counter == YIELD_INTERVAL {
5971                accessed_row_counter = 0;
5972                yield_now().await;
5973            }
5974            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5975                start_indent = Some((row, indent));
5976                break;
5977            }
5978        }
5979        let (start_row, start_indent_size) = start_indent?;
5980
5981        let mut end_indent = (end, None);
5982        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5983            if row > end {
5984                break;
5985            }
5986            accessed_row_counter += 1;
5987            if accessed_row_counter == YIELD_INTERVAL {
5988                accessed_row_counter = 0;
5989                yield_now().await;
5990            }
5991            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5992                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5993                break;
5994            }
5995        }
5996        let (end_row, end_indent_size) = end_indent;
5997
5998        let indent = if let Some(end_indent_size) = end_indent_size {
5999            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6000                start_indent_size
6001            } else {
6002                end_indent_size
6003            }
6004        } else {
6005            start_indent_size
6006        };
6007
6008        Some((start_row..end_row, indent))
6009    }
6010
6011    pub fn indent_guides_in_range<T: ToPoint>(
6012        &self,
6013        range: Range<T>,
6014        ignore_disabled_for_language: bool,
6015        cx: &App,
6016    ) -> impl Iterator<Item = IndentGuide> {
6017        let range = range.start.to_point(self)..range.end.to_point(self);
6018        let start_row = MultiBufferRow(range.start.row);
6019        let end_row = MultiBufferRow(range.end.row);
6020
6021        let mut row_indents = self.line_indents(start_row, |buffer| {
6022            let settings =
6023                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6024            settings.indent_guides.enabled || ignore_disabled_for_language
6025        });
6026
6027        let mut result = Vec::new();
6028        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6029
6030        let mut prev_settings = None;
6031        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6032            if first_row > end_row {
6033                break;
6034            }
6035            let current_depth = indent_stack.len() as u32;
6036
6037            // Avoid retrieving the language settings repeatedly for every buffer row.
6038            if let Some((prev_buffer_id, _)) = &prev_settings
6039                && prev_buffer_id != &buffer.remote_id()
6040            {
6041                prev_settings.take();
6042            }
6043            let settings = &prev_settings
6044                .get_or_insert_with(|| {
6045                    (
6046                        buffer.remote_id(),
6047                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6048                    )
6049                })
6050                .1;
6051            let tab_size = settings.tab_size.get();
6052
6053            // When encountering empty, continue until found useful line indent
6054            // then add to the indent stack with the depth found
6055            let mut found_indent = false;
6056            let mut last_row = first_row;
6057            if line_indent.is_line_blank() {
6058                while !found_indent {
6059                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6060                        break;
6061                    };
6062                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6063                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6064                        break;
6065                    }
6066
6067                    if new_line_indent.is_line_blank() {
6068                        continue;
6069                    }
6070                    last_row = target_row.min(end_row);
6071                    line_indent = new_line_indent;
6072                    found_indent = true;
6073                    break;
6074                }
6075            } else {
6076                found_indent = true
6077            }
6078
6079            let depth = if found_indent {
6080                line_indent.len(tab_size) / tab_size
6081            } else {
6082                0
6083            };
6084
6085            match depth.cmp(&current_depth) {
6086                cmp::Ordering::Less => {
6087                    for _ in 0..(current_depth - depth) {
6088                        let mut indent = indent_stack.pop().unwrap();
6089                        if last_row != first_row {
6090                            // In this case, we landed on an empty row, had to seek forward,
6091                            // and discovered that the indent we where on is ending.
6092                            // This means that the last display row must
6093                            // be on line that ends this indent range, so we
6094                            // should display the range up to the first non-empty line
6095                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6096                        }
6097
6098                        result.push(indent)
6099                    }
6100                }
6101                cmp::Ordering::Greater => {
6102                    for next_depth in current_depth..depth {
6103                        indent_stack.push(IndentGuide {
6104                            buffer_id: buffer.remote_id(),
6105                            start_row: first_row,
6106                            end_row: last_row,
6107                            depth: next_depth,
6108                            tab_size,
6109                            settings: settings.indent_guides.clone(),
6110                        });
6111                    }
6112                }
6113                _ => {}
6114            }
6115
6116            for indent in indent_stack.iter_mut() {
6117                indent.end_row = last_row;
6118            }
6119        }
6120
6121        result.extend(indent_stack);
6122        result.into_iter()
6123    }
6124
6125    pub fn trailing_excerpt_update_count(&self) -> usize {
6126        self.trailing_excerpt_update_count
6127    }
6128
6129    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6130        self.point_to_buffer_offset(point)
6131            .and_then(|(buffer, _)| buffer.file())
6132    }
6133
6134    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6135        self.point_to_buffer_offset(offset)
6136            .and_then(|(buffer, offset)| buffer.language_at(offset))
6137    }
6138
6139    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6140        self.excerpts
6141            .first()
6142            .map(|excerpt| &excerpt.buffer)
6143            .map(|buffer| {
6144                language_settings(
6145                    buffer.language().map(|language| language.name()),
6146                    buffer.file(),
6147                    cx,
6148                )
6149            })
6150            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6151    }
6152
6153    pub fn language_settings_at<'a, T: ToOffset>(
6154        &'a self,
6155        point: T,
6156        cx: &'a App,
6157    ) -> Cow<'a, LanguageSettings> {
6158        let mut language = None;
6159        let mut file = None;
6160        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6161            language = buffer.language_at(offset);
6162            file = buffer.file();
6163        }
6164        language_settings(language.map(|l| l.name()), file, cx)
6165    }
6166
6167    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6168        self.point_to_buffer_offset(point)
6169            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6170    }
6171
6172    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6173        self.point_to_buffer_offset(point)
6174            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6175            .unwrap_or_default()
6176    }
6177
6178    pub fn language_indent_size_at<T: ToOffset>(
6179        &self,
6180        position: T,
6181        cx: &App,
6182    ) -> Option<IndentSize> {
6183        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6184        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6185    }
6186
6187    pub fn is_dirty(&self) -> bool {
6188        self.is_dirty
6189    }
6190
6191    pub fn has_deleted_file(&self) -> bool {
6192        self.has_deleted_file
6193    }
6194
6195    pub fn has_conflict(&self) -> bool {
6196        self.has_conflict
6197    }
6198
6199    pub fn has_diagnostics(&self) -> bool {
6200        self.excerpts
6201            .iter()
6202            .any(|excerpt| excerpt.buffer.has_diagnostics())
6203    }
6204
6205    pub fn diagnostic_group(
6206        &self,
6207        buffer_id: BufferId,
6208        group_id: usize,
6209    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6210        self.lift_buffer_metadata::<Point, _, _>(
6211            Point::zero()..self.max_point(),
6212            move |buffer, range| {
6213                if buffer.remote_id() != buffer_id {
6214                    return None;
6215                };
6216                Some(
6217                    buffer
6218                        .diagnostics_in_range(range, false)
6219                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6220                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6221                )
6222            },
6223        )
6224        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6225    }
6226
6227    pub fn diagnostics_in_range<'a, MBD>(
6228        &'a self,
6229        range: Range<MBD>,
6230    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6231    where
6232        MBD::TextDimension: 'a
6233            + text::ToOffset
6234            + text::FromAnchor
6235            + Sub<Output = MBD::TextDimension>
6236            + fmt::Debug
6237            + ops::Add<Output = MBD::TextDimension>
6238            + ops::AddAssign
6239            + Ord,
6240        MBD: MultiBufferDimension
6241            + Ord
6242            + Sub<Output = MBD::TextDimension>
6243            + ops::Add<MBD::TextDimension, Output = MBD>
6244            + ops::AddAssign<MBD::TextDimension>
6245            + 'a,
6246    {
6247        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6248            Some(
6249                buffer
6250                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6251                    .map(|entry| (entry.range, entry.diagnostic)),
6252            )
6253        })
6254        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6255    }
6256
6257    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6258        &'a self,
6259        range: Range<MBD>,
6260    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6261    where
6262        MBD: MultiBufferDimension
6263            + Ord
6264            + Sub<Output = MBD::TextDimension>
6265            + ops::Add<MBD::TextDimension, Output = MBD>
6266            + ops::AddAssign<MBD::TextDimension>,
6267        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6268            + ops::Add<Output = MBD::TextDimension>
6269            + text::ToOffset
6270            + text::FromAnchor
6271            + AddAssign<MBD::TextDimension>
6272            + Ord,
6273    {
6274        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6275            Some(
6276                buffer
6277                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6278                    .map(|entry| (entry.range, entry.diagnostic)),
6279            )
6280        })
6281        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6282    }
6283
6284    pub fn syntax_ancestor<T: ToOffset>(
6285        &self,
6286        range: Range<T>,
6287    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6288        let range = range.start.to_offset(self)..range.end.to_offset(self);
6289        let mut excerpt = self.excerpt_containing(range.clone())?;
6290        let node = excerpt
6291            .buffer()
6292            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6293        let node_range = node.byte_range();
6294        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6295        if !excerpt.contains_buffer_range(node_range.clone()) {
6296            return None;
6297        };
6298        Some((node, excerpt.map_range_from_buffer(node_range)))
6299    }
6300
6301    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6302        let (excerpt_id, _, buffer) = self.as_singleton()?;
6303        let outline = buffer.outline(theme);
6304        Some(Outline::new(
6305            outline
6306                .items
6307                .into_iter()
6308                .flat_map(|item| {
6309                    Some(OutlineItem {
6310                        depth: item.depth,
6311                        range: self.anchor_range_in_buffer(excerpt_id, item.range)?,
6312                        source_range_for_text: self
6313                            .anchor_range_in_buffer(excerpt_id, item.source_range_for_text)?,
6314                        text: item.text,
6315                        highlight_ranges: item.highlight_ranges,
6316                        name_ranges: item.name_ranges,
6317                        body_range: item.body_range.and_then(|body_range| {
6318                            self.anchor_range_in_buffer(excerpt_id, body_range)
6319                        }),
6320                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6321                            self.anchor_range_in_buffer(excerpt_id, annotation_range)
6322                        }),
6323                    })
6324                })
6325                .collect(),
6326        ))
6327    }
6328
6329    pub fn symbols_containing<T: ToOffset>(
6330        &self,
6331        offset: T,
6332        theme: Option<&SyntaxTheme>,
6333    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6334        let anchor = self.anchor_before(offset);
6335        let excerpt @ &Excerpt {
6336            id: excerpt_id,
6337            buffer_id,
6338            ref buffer,
6339            ..
6340        } = self.excerpt(anchor.excerpt_id)?;
6341        if cfg!(debug_assertions) {
6342            match anchor.text_anchor.buffer_id {
6343                // we clearly are hitting this according to sentry, but in what situations can this occur?
6344                Some(anchor_buffer_id) => {
6345                    assert_eq!(
6346                        anchor_buffer_id, buffer_id,
6347                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6348                    )
6349                }
6350                None => assert!(anchor.is_max()),
6351            }
6352        };
6353        Some((
6354            buffer_id,
6355            buffer
6356                .symbols_containing(anchor.text_anchor, theme)
6357                .into_iter()
6358                .flat_map(|item| {
6359                    Some(OutlineItem {
6360                        depth: item.depth,
6361                        source_range_for_text: Anchor::range_in_buffer(
6362                            excerpt_id,
6363                            item.source_range_for_text,
6364                        ),
6365                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6366                        text: item.text,
6367                        highlight_ranges: item.highlight_ranges,
6368                        name_ranges: item.name_ranges,
6369                        body_range: item
6370                            .body_range
6371                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6372                        annotation_range: item
6373                            .annotation_range
6374                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6375                    })
6376                })
6377                .collect(),
6378        ))
6379    }
6380
6381    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6382        todo!()
6383    }
6384
6385    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6386        self.path_keys_by_buffer.get(&buffer_id)
6387    }
6388
6389    pub fn first_excerpt_for_buffer(&self, buffer_id: BufferId) -> Option<&Excerpt> {
6390        let path_key = self.path_keys_by_buffer.get(&buffer_id)?;
6391        let (_, _, first_excerpt) =
6392            self.excerpts
6393                .find::<ExcerptSummary, _>((), path_key, Bias::Left);
6394        first_excerpt
6395    }
6396
6397    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6398        self.buffer_for_path(self.path_keys_by_buffer.get(&id)?)
6399    }
6400
6401    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6402        self.path_keys_by_index.get(&anchor.path).cloned()
6403    }
6404
6405    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6406        self.try_path_for_anchor(anchor)
6407            .expect("invalid anchor: path was never added to multibuffer")
6408    }
6409
6410    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6411        let mut cursor = self
6412            .excerpts
6413            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6414        let locator = self.excerpt_locator_for_id(excerpt_id);
6415        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6416        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6417            sought_exact = true;
6418            cursor.prev();
6419        } else if excerpt_id == ExcerptId::min() {
6420            sought_exact = true;
6421        }
6422        if sought_exact {
6423            let start = cursor.start().1;
6424            let end = cursor.end().1;
6425            let mut diff_transforms = self
6426                .diff_transforms
6427                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6428            diff_transforms.seek(&start, Bias::Left);
6429            let overshoot = start - diff_transforms.start().0;
6430            let start = diff_transforms.start().1 + overshoot;
6431            diff_transforms.seek(&end, Bias::Right);
6432            let overshoot = end - diff_transforms.start().0;
6433            let end = diff_transforms.start().1 + overshoot;
6434            Some(start.0..end.0)
6435        } else {
6436            None
6437        }
6438    }
6439
6440    // todo!() sort out excerpt_containing etc.
6441    fn excerpt_at(&self, position: impl ToOffset) -> Option<&Excerpt> {
6442        todo!()
6443    }
6444
6445    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6446    pub fn excerpt_containing<T: ToOffset>(
6447        &self,
6448        range: Range<T>,
6449    ) -> Option<MultiBufferExcerpt<'_>> {
6450        let range = range.start.to_offset(self)..range.end.to_offset(self);
6451        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6452        cursor.seek(&range.start);
6453
6454        let start_excerpt = cursor.excerpt()?;
6455        if range.end != range.start {
6456            cursor.seek_forward(&range.end);
6457            if cursor.excerpt()?.id != start_excerpt.id {
6458                return None;
6459            }
6460        }
6461
6462        cursor.seek_to_start_of_current_excerpt();
6463        let region = cursor.region()?;
6464        let offset = region.range.start;
6465        let buffer_offset = start_excerpt.buffer_start_offset();
6466        let excerpt_offset = *cursor.excerpts.start();
6467        Some(MultiBufferExcerpt {
6468            diff_transforms: cursor.diff_transforms,
6469            excerpt: start_excerpt,
6470            offset,
6471            buffer_offset,
6472            excerpt_offset,
6473        })
6474    }
6475
6476    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6477        match anchor {
6478            Anchor::Min => self
6479                .excerpts
6480                .first()
6481                .map(|excerpt| excerpt.buffer.remote_id()),
6482            Anchor::Excerpt(excerpt_anchor) => Some(excerpt_anchor.buffer_id),
6483            Anchor::Max => self
6484                .excerpts
6485                .last()
6486                .map(|excerpt| excerpt.buffer.remote_id()),
6487        }
6488    }
6489
6490    pub fn selections_in_range<'a>(
6491        &'a self,
6492        range: &'a Range<Anchor>,
6493        include_local: bool,
6494    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6495        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6496        cursor.seek(&range.start.seek_target(self), Bias::Left);
6497        cursor
6498            .take_while(move |excerpt| {
6499                let excerpt_start =
6500                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6501                excerpt_start.cmp(&range.end, self).is_le()
6502            })
6503            .flat_map(move |excerpt| {
6504                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6505                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6506                    && excerpt.contains(&excerpt_anchor)
6507                {
6508                    query_range.start = excerpt_anchor.text_anchor();
6509                }
6510                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6511                    && excerpt.contains(&excerpt_anchor)
6512                {
6513                    query_range.end = excerpt_anchor.text_anchor();
6514                }
6515
6516                excerpt
6517                    .buffer
6518                    .selections_in_range(query_range, include_local)
6519                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6520                        selections.map(move |selection| {
6521                            let mut start =
6522                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6523                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6524                            if range.start.cmp(&start, self).is_gt() {
6525                                start = range.start;
6526                            }
6527                            if range.end.cmp(&end, self).is_lt() {
6528                                end = range.end;
6529                            }
6530
6531                            (
6532                                replica_id,
6533                                line_mode,
6534                                cursor_shape,
6535                                Selection {
6536                                    id: selection.id,
6537                                    start,
6538                                    end,
6539                                    reversed: selection.reversed,
6540                                    goal: selection.goal,
6541                                },
6542                            )
6543                        })
6544                    })
6545            })
6546    }
6547
6548    pub fn show_headers(&self) -> bool {
6549        self.show_headers
6550    }
6551
6552    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6553        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6554    }
6555
6556    pub fn all_diff_hunks_expanded(&self) -> bool {
6557        self.all_diff_hunks_expanded
6558    }
6559
6560    /// Visually annotates a position or range with the `Debug` representation of a value. The
6561    /// callsite of this function is used as a key - previous annotations will be removed.
6562    #[cfg(debug_assertions)]
6563    #[track_caller]
6564    pub fn debug<V, R>(&self, ranges: &R, value: V)
6565    where
6566        R: debug::ToMultiBufferDebugRanges,
6567        V: std::fmt::Debug,
6568    {
6569        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6570    }
6571
6572    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6573    /// debug annotations with the same key will be removed. The key is also used to determine the
6574    /// annotation's color.
6575    #[cfg(debug_assertions)]
6576    #[track_caller]
6577    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6578    where
6579        K: std::hash::Hash + 'static,
6580        R: debug::ToMultiBufferDebugRanges,
6581        V: std::fmt::Debug,
6582    {
6583        let text_ranges = ranges
6584            .to_multi_buffer_debug_ranges(self)
6585            .into_iter()
6586            .flat_map(|range| {
6587                self.range_to_buffer_ranges(range.start..=range.end)
6588                    .into_iter()
6589                    .map(|(buffer, range, _excerpt_id)| {
6590                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6591                    })
6592            })
6593            .collect();
6594        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6595            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6596        });
6597    }
6598
6599    fn excerpt_edits_for_diff_change(
6600        &self,
6601        path: &PathKey,
6602        diff_change_range: Range<usize>,
6603    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6604        let mut excerpt_edits = Vec::new();
6605        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6606        cursor.seek(path, Bias::Left);
6607        while let Some(excerpt) = cursor.item()
6608            && &excerpt.path_key == path
6609        {
6610            let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6611            let excerpt_start = cursor.start().clone();
6612            let excerpt_len = excerpt.text_summary.len;
6613            cursor.next();
6614            if diff_change_range.end < excerpt_buffer_range.start
6615                || diff_change_range.start > excerpt_buffer_range.end
6616            {
6617                continue;
6618            }
6619            let diff_change_start_in_excerpt = diff_change_range
6620                .start
6621                .saturating_sub(excerpt_buffer_range.start);
6622            let diff_change_end_in_excerpt = diff_change_range
6623                .end
6624                .saturating_sub(excerpt_buffer_range.start);
6625            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6626            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6627            excerpt_edits.push(Edit {
6628                old: edit_start..edit_end,
6629                new: edit_start..edit_end,
6630            });
6631        }
6632        excerpt_edits
6633    }
6634
6635    fn excerpts_for_path<'a>(
6636        &'a self,
6637        path_key: &'a PathKey,
6638    ) -> impl Iterator<Item = ExcerptInfo> + 'a {
6639        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6640        cursor.seek(path_key, Bias::Left);
6641        cursor
6642            .take_while(move |item| &item.path_key == path_key)
6643            .map(|excerpt| excerpt.info())
6644    }
6645}
6646
6647#[cfg(any(test, feature = "test-support"))]
6648impl MultiBufferSnapshot {
6649    pub fn random_byte_range(
6650        &self,
6651        start_offset: MultiBufferOffset,
6652        rng: &mut impl rand::Rng,
6653    ) -> Range<MultiBufferOffset> {
6654        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6655        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6656        start..end
6657    }
6658
6659    #[cfg(any(test, feature = "test-support"))]
6660    fn check_invariants(&self) {
6661        let excerpts = self.excerpts.items(());
6662
6663        let all_buffer_path_keys = HashSet::from_iter(self.path_keys_by_buffer.values().cloned());
6664        let all_excerpt_path_keys = HashSet::from_iter(excerpts.iter().map(|e| e.path_key.clone()));
6665
6666        for (ix, excerpt) in excerpts.iter().enumerate() {
6667            if ix > 0 {
6668                let prev = &excerpts[ix - 1];
6669
6670                if excerpt.path_key < prev.path_key {
6671                    panic!("excerpt path_keys are out-of-order: {:?}", excerpts);
6672                } else if excerpt.path_key == prev.path_key {
6673                    if excerpt
6674                        .start_anchor()
6675                        .cmp(&prev.end_anchor(), &self)
6676                        .is_le()
6677                    {
6678                        panic!("excerpt anchors are out-of-order: {:?}", excerpts);
6679                    }
6680                    if excerpt
6681                        .start_anchor()
6682                        .cmp(&excerpt.end_anchor(), &self)
6683                        .is_ge()
6684                    {
6685                        panic!("excerpt with backward range: {:?}", excerpts);
6686                    }
6687                }
6688            }
6689            assert!(
6690                all_buffer_path_keys.contains(&excerpt.path_key),
6691                "excerpt path key not found in active path keys: {:?}",
6692                excerpt.path_key
6693            );
6694            assert_eq!(
6695                self.path_keys_by_index.get(&excerpt.path_key_index),
6696                Some(&excerpt.path_key),
6697                "excerpt path key index does not match path key: {:?}",
6698                excerpt.path_key,
6699            );
6700        }
6701        assert_eq!(all_buffer_path_keys, all_excerpt_path_keys);
6702
6703        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6704            panic!(
6705                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6706                self.excerpts.summary().text,
6707                self.diff_transforms.summary().input,
6708                self.diff_transforms.items(()),
6709            );
6710        }
6711
6712        let mut prev_transform: Option<&DiffTransform> = None;
6713        for item in self.diff_transforms.iter() {
6714            if let DiffTransform::BufferContent {
6715                summary,
6716                inserted_hunk_info,
6717            } = item
6718            {
6719                if let Some(DiffTransform::BufferContent {
6720                    inserted_hunk_info: prev_inserted_hunk_info,
6721                    ..
6722                }) = prev_transform
6723                    && *inserted_hunk_info == *prev_inserted_hunk_info
6724                {
6725                    panic!(
6726                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6727                        self.diff_transforms.items(())
6728                    );
6729                }
6730                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6731                    panic!("empty buffer content transform");
6732                }
6733            }
6734            prev_transform = Some(item);
6735        }
6736    }
6737}
6738
6739impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6740where
6741    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6742    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6743{
6744    #[instrument(skip_all)]
6745    fn seek(&mut self, position: &MBD) {
6746        let position = OutputDimension(*position);
6747        self.cached_region.take();
6748        self.diff_transforms.seek(&position, Bias::Right);
6749        if self.diff_transforms.item().is_none()
6750            && self.diff_transforms.start().output_dimension == position
6751        {
6752            self.diff_transforms.prev();
6753        }
6754
6755        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6756        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6757            let overshoot = position - self.diff_transforms.start().output_dimension;
6758            excerpt_position += overshoot;
6759        }
6760
6761        self.excerpts.seek(&excerpt_position, Bias::Right);
6762        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6763            self.excerpts.prev();
6764        }
6765    }
6766
6767    fn seek_forward(&mut self, position: &MBD) {
6768        let position = OutputDimension(*position);
6769        self.cached_region.take();
6770        self.diff_transforms.seek_forward(&position, Bias::Right);
6771        if self.diff_transforms.item().is_none()
6772            && self.diff_transforms.start().output_dimension == position
6773        {
6774            self.diff_transforms.prev();
6775        }
6776
6777        let overshoot = position - self.diff_transforms.start().output_dimension;
6778        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6779        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6780            excerpt_position += overshoot;
6781        }
6782
6783        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6784        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6785            self.excerpts.prev();
6786        }
6787    }
6788
6789    fn next_excerpt(&mut self) {
6790        self.excerpts.next();
6791        self.seek_to_start_of_current_excerpt();
6792    }
6793
6794    fn prev_excerpt(&mut self) {
6795        self.excerpts.prev();
6796        self.seek_to_start_of_current_excerpt();
6797    }
6798
6799    fn seek_to_start_of_current_excerpt(&mut self) {
6800        self.cached_region.take();
6801
6802        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6803            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6804            && self.diff_transforms.next_item().is_some()
6805        {
6806            self.diff_transforms.next();
6807        }
6808    }
6809
6810    fn next_excerpt_forwards(&mut self) {
6811        self.excerpts.next();
6812        self.seek_to_start_of_current_excerpt_forward();
6813    }
6814
6815    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6816        self.cached_region.take();
6817
6818        if self
6819            .diff_transforms
6820            .seek_forward(self.excerpts.start(), Bias::Left)
6821            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6822            && self.diff_transforms.next_item().is_some()
6823        {
6824            self.diff_transforms.next();
6825        }
6826    }
6827
6828    fn next(&mut self) {
6829        self.cached_region.take();
6830        match self
6831            .diff_transforms
6832            .end()
6833            .excerpt_dimension
6834            .cmp(&self.excerpts.end())
6835        {
6836            cmp::Ordering::Less => self.diff_transforms.next(),
6837            cmp::Ordering::Greater => self.excerpts.next(),
6838            cmp::Ordering::Equal => {
6839                self.diff_transforms.next();
6840                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6841                    || self.diff_transforms.item().is_none()
6842                {
6843                    self.excerpts.next();
6844                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6845                    self.diff_transforms.item()
6846                    && self
6847                        .excerpts
6848                        .item()
6849                        .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end)
6850                {
6851                    self.excerpts.next();
6852                }
6853            }
6854        }
6855    }
6856
6857    fn prev(&mut self) {
6858        self.cached_region.take();
6859        match self
6860            .diff_transforms
6861            .start()
6862            .excerpt_dimension
6863            .cmp(self.excerpts.start())
6864        {
6865            cmp::Ordering::Less => self.excerpts.prev(),
6866            cmp::Ordering::Greater => self.diff_transforms.prev(),
6867            cmp::Ordering::Equal => {
6868                self.diff_transforms.prev();
6869                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6870                    || self.diff_transforms.item().is_none()
6871                {
6872                    self.excerpts.prev();
6873                }
6874            }
6875        }
6876    }
6877
6878    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
6879        self.cached_region
6880            .get_or_init(|| self.build_region())
6881            .as_ref()
6882    }
6883
6884    fn is_at_start_of_excerpt(&mut self) -> bool {
6885        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6886            return false;
6887        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6888            return true;
6889        }
6890
6891        self.diff_transforms.prev();
6892        let prev_transform = self.diff_transforms.item();
6893        self.diff_transforms.next();
6894
6895        prev_transform.is_none_or(|next_transform| {
6896            matches!(next_transform, DiffTransform::BufferContent { .. })
6897        })
6898    }
6899
6900    fn is_at_end_of_excerpt(&self) -> bool {
6901        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6902            return false;
6903        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6904            || self.diff_transforms.item().is_none()
6905        {
6906            return true;
6907        }
6908
6909        let next_transform = self.diff_transforms.next_item();
6910        next_transform.is_none_or(|next_transform| match next_transform {
6911            DiffTransform::BufferContent { .. } => true,
6912            DiffTransform::DeletedHunk { hunk_info, .. } => self
6913                .excerpts
6914                .item()
6915                .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end),
6916        })
6917    }
6918
6919    fn main_buffer_position(&self) -> Option<BD> {
6920        let excerpt = self.excerpts.item()?;
6921        let buffer = &excerpt.buffer;
6922        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6923        let mut buffer_start = buffer_context_start;
6924        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6925        buffer_start += overshoot;
6926        Some(buffer_start)
6927    }
6928
6929    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6930        let excerpt = self.excerpts.item()?;
6931        match self.diff_transforms.item()? {
6932            DiffTransform::DeletedHunk {
6933                buffer_id,
6934                base_text_byte_range,
6935                has_trailing_newline,
6936                hunk_info,
6937                ..
6938            } => {
6939                let diff = self.diffs.get(buffer_id)?;
6940                let buffer = diff.base_text();
6941                let mut rope_cursor = buffer.as_rope().cursor(0);
6942                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6943                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6944                let mut buffer_end = buffer_start;
6945                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6946                let start = self.diff_transforms.start().output_dimension.0;
6947                let end = self.diff_transforms.end().output_dimension.0;
6948                Some(MultiBufferRegion {
6949                    buffer,
6950                    excerpt,
6951                    has_trailing_newline: *has_trailing_newline,
6952                    is_main_buffer: false,
6953                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6954                        hunk_info.hunk_secondary_status,
6955                    )),
6956                    buffer_range: buffer_start..buffer_end,
6957                    range: start..end,
6958                })
6959            }
6960            DiffTransform::BufferContent {
6961                inserted_hunk_info, ..
6962            } => {
6963                let buffer = &excerpt.buffer;
6964                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6965
6966                let mut start = self.diff_transforms.start().output_dimension.0;
6967                let mut buffer_start = buffer_context_start;
6968                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6969                    let overshoot =
6970                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6971                    start += overshoot;
6972                } else {
6973                    let overshoot =
6974                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6975                    buffer_start += overshoot;
6976                }
6977
6978                let mut end;
6979                let mut buffer_end;
6980                let has_trailing_newline;
6981                let transform_end = self.diff_transforms.end();
6982                if transform_end.excerpt_dimension < self.excerpts.end() {
6983                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
6984                    end = transform_end.output_dimension.0;
6985                    buffer_end = buffer_context_start;
6986                    buffer_end += overshoot;
6987                    has_trailing_newline = false;
6988                } else {
6989                    let overshoot =
6990                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6991                    end = self.diff_transforms.start().output_dimension.0;
6992                    end += overshoot;
6993                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6994                    has_trailing_newline = excerpt.has_trailing_newline;
6995                };
6996
6997                let diff_hunk_status = inserted_hunk_info.map(|info| {
6998                    if info.is_logically_deleted {
6999                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7000                    } else {
7001                        DiffHunkStatus::added(info.hunk_secondary_status)
7002                    }
7003                });
7004
7005                Some(MultiBufferRegion {
7006                    buffer,
7007                    excerpt,
7008                    has_trailing_newline,
7009                    is_main_buffer: true,
7010                    diff_hunk_status,
7011                    buffer_range: buffer_start..buffer_end,
7012                    range: start..end,
7013                })
7014            }
7015        }
7016    }
7017
7018    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7019        let excerpt = self.excerpts.item()?;
7020        match self.diff_transforms.item()? {
7021            &DiffTransform::DeletedHunk { .. } => {
7022                let start = self.diff_transforms.start().output_dimension.0;
7023                let end = self.diff_transforms.end().output_dimension.0;
7024                Some((excerpt, start..end))
7025            }
7026            DiffTransform::BufferContent { .. } => {
7027                let mut start = self.diff_transforms.start().output_dimension.0;
7028                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7029                    let overshoot =
7030                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7031                    start += overshoot;
7032                }
7033
7034                let mut end;
7035                let transform_end = self.diff_transforms.end();
7036                if transform_end.excerpt_dimension < self.excerpts.end() {
7037                    end = transform_end.output_dimension.0;
7038                } else {
7039                    let overshoot =
7040                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7041                    end = self.diff_transforms.start().output_dimension.0;
7042                    end += overshoot;
7043                };
7044
7045                Some((excerpt, start..end))
7046            }
7047        }
7048    }
7049
7050    fn excerpt(&self) -> Option<&'a Excerpt> {
7051        self.excerpts.item()
7052    }
7053}
7054
7055impl Excerpt {
7056    fn new(
7057        path_key: PathKey,
7058        path_key_index: PathKeyIndex,
7059        buffer: Arc<BufferSnapshot>,
7060        range: ExcerptRange<text::Anchor>,
7061        has_trailing_newline: bool,
7062    ) -> Self {
7063        Excerpt {
7064            path_key,
7065            path_key_index,
7066            max_buffer_row: range.context.end.to_point(&buffer).row,
7067            text_summary: buffer
7068                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7069            buffer,
7070            range,
7071            has_trailing_newline,
7072        }
7073    }
7074
7075    fn info(&self) -> ExcerptInfo {
7076        ExcerptInfo {
7077            path_key_index: self.path_key_index,
7078            buffer_id: self.buffer.remote_id(),
7079            range: self.range.clone(),
7080        }
7081    }
7082
7083    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7084        let content_start = self.range.context.start.to_offset(&self.buffer);
7085        let chunks_start = content_start + range.start;
7086        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7087
7088        let has_footer = self.has_trailing_newline
7089            && range.start <= self.text_summary.len
7090            && range.end > self.text_summary.len;
7091
7092        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7093
7094        ExcerptChunks {
7095            content_chunks,
7096            has_footer,
7097            end: self.end_anchor(),
7098        }
7099    }
7100
7101    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7102        let content_start = self.range.context.start.to_offset(&self.buffer);
7103        let chunks_start = content_start + range.start;
7104        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7105        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7106        excerpt_chunks.has_footer = self.has_trailing_newline
7107            && range.start <= self.text_summary.len
7108            && range.end > self.text_summary.len;
7109    }
7110
7111    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7112        if text_anchor
7113            .cmp(&self.range.context.start, &self.buffer)
7114            .is_lt()
7115        {
7116            self.range.context.start
7117        } else if text_anchor
7118            .cmp(&self.range.context.end, &self.buffer)
7119            .is_gt()
7120        {
7121            self.range.context.end
7122        } else {
7123            text_anchor
7124        }
7125    }
7126
7127    pub(crate) fn contains(&self, anchor: &ExcerptAnchor) -> bool {
7128        self.path_key_index == anchor.path
7129            && self.buffer.remote_id() == anchor.buffer_id
7130            && self.range.contains(&anchor.text_anchor(), &self.buffer)
7131    }
7132
7133    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7134    fn buffer_start_offset(&self) -> BufferOffset {
7135        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7136    }
7137
7138    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7139    fn buffer_end_offset(&self) -> BufferOffset {
7140        self.buffer_start_offset() + self.text_summary.len
7141    }
7142
7143    fn start_anchor(&self) -> ExcerptAnchor {
7144        todo!()
7145    }
7146
7147    fn end_anchor(&self) -> ExcerptAnchor {
7148        todo!()
7149    }
7150}
7151
7152impl PartialEq for Excerpt {
7153    fn eq(&self, other: &Self) -> bool {
7154        self.buffer.remote_id() == other.buffer.remote_id()
7155            && self.range.context == other.range.context
7156    }
7157}
7158
7159impl<'a> MultiBufferExcerpt<'a> {
7160    pub fn buffer_id(&self) -> BufferId {
7161        self.excerpt.buffer.remote_id()
7162    }
7163
7164    pub fn start_anchor(&self) -> Anchor {
7165        Anchor::in_buffer(
7166            self.excerpt.path_key_index,
7167            self.excerpt.range.context.start,
7168        )
7169    }
7170
7171    pub fn end_anchor(&self) -> Anchor {
7172        Anchor::in_buffer(self.excerpt.path_key_index, self.excerpt.range.context.end)
7173    }
7174
7175    pub fn buffer(&self) -> &'a BufferSnapshot {
7176        &self.excerpt.buffer
7177    }
7178
7179    pub fn buffer_range(&self) -> Range<BufferOffset> {
7180        self.buffer_offset
7181            ..BufferOffset(
7182                self.excerpt
7183                    .range
7184                    .context
7185                    .end
7186                    .to_offset(&self.excerpt.buffer.text),
7187            )
7188    }
7189
7190    pub fn start_offset(&self) -> MultiBufferOffset {
7191        self.offset
7192    }
7193
7194    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7195    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7196        self.map_range_to_buffer(offset..offset).start
7197    }
7198
7199    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7200    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7201        self.diff_transforms
7202            .seek(&OutputDimension(range.start), Bias::Right);
7203        let start = self.map_offset_to_buffer_internal(range.start);
7204        let end = if range.end > range.start {
7205            self.diff_transforms
7206                .seek_forward(&OutputDimension(range.end), Bias::Right);
7207            self.map_offset_to_buffer_internal(range.end)
7208        } else {
7209            start
7210        };
7211        start..end
7212    }
7213
7214    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7215        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7216        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7217            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7218        };
7219        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7220        self.buffer_offset + offset_in_excerpt
7221    }
7222
7223    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7224    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7225        self.map_range_from_buffer(buffer_offset..buffer_offset)
7226            .start
7227    }
7228
7229    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7230    pub fn map_range_from_buffer(
7231        &mut self,
7232        buffer_range: Range<BufferOffset>,
7233    ) -> Range<MultiBufferOffset> {
7234        if buffer_range.start < self.buffer_offset {
7235            log::warn!(
7236                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7237            );
7238            return self.offset..self.offset;
7239        }
7240        let overshoot = buffer_range.start - self.buffer_offset;
7241        let excerpt_offset = self.excerpt_offset + overshoot;
7242        let excerpt_seek_dim = excerpt_offset;
7243        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7244        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7245            log::warn!(
7246                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7247            );
7248            return self.offset..self.offset;
7249        }
7250        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7251        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7252
7253        let end = if buffer_range.start < buffer_range.end {
7254            let overshoot = buffer_range.end - self.buffer_offset;
7255            let excerpt_offset = self.excerpt_offset + overshoot;
7256            let excerpt_seek_dim = excerpt_offset;
7257            self.diff_transforms
7258                .seek_forward(&excerpt_seek_dim, Bias::Right);
7259            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7260            // todo(lw): Clamp end to the excerpt boundaries
7261            self.diff_transforms.start().output_dimension.0 + overshoot
7262        } else {
7263            start
7264        };
7265
7266        start..end
7267    }
7268
7269    /// Returns true if the entirety of the given range is in the buffer's excerpt
7270    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7271        range.start >= self.excerpt.buffer_start_offset()
7272            && range.end <= self.excerpt.buffer_end_offset()
7273    }
7274
7275    /// Returns true if any part of the given range is in the buffer's excerpt
7276    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7277        range.start <= self.excerpt.buffer_end_offset()
7278            && range.end >= self.excerpt.buffer_start_offset()
7279    }
7280
7281    pub fn max_buffer_row(&self) -> u32 {
7282        self.excerpt.max_buffer_row
7283    }
7284}
7285
7286impl fmt::Debug for Excerpt {
7287    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7288        f.debug_struct("Excerpt")
7289            .field("path_key", &self.path_key)
7290            .field("range", &self.range)
7291            .field("text_summary", &self.text_summary)
7292            .field("has_trailing_newline", &self.has_trailing_newline)
7293            .finish()
7294    }
7295}
7296
7297impl sum_tree::Item for Excerpt {
7298    type Summary = ExcerptSummary;
7299
7300    fn summary(&self, _cx: ()) -> Self::Summary {
7301        let mut text = self.text_summary;
7302        if self.has_trailing_newline {
7303            text += TextSummary::from("\n");
7304        }
7305        ExcerptSummary {
7306            path_key: self.path_key.clone(),
7307            max_anchor: self.range.context.end,
7308            widest_line_number: self.max_buffer_row,
7309            text: text.into(),
7310            count: 1,
7311        }
7312    }
7313}
7314
7315impl DiffTransform {
7316    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7317        match self {
7318            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7319            DiffTransform::BufferContent {
7320                inserted_hunk_info, ..
7321            } => *inserted_hunk_info,
7322        }
7323    }
7324}
7325
7326impl sum_tree::Item for DiffTransform {
7327    type Summary = DiffTransformSummary;
7328
7329    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7330        match self {
7331            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7332                input: *summary,
7333                output: *summary,
7334            },
7335            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7336                input: MBTextSummary::default(),
7337                output: summary.into(),
7338            },
7339        }
7340    }
7341}
7342
7343impl DiffTransformSummary {
7344    fn excerpt_len(&self) -> ExcerptOffset {
7345        ExcerptDimension(self.input.len)
7346    }
7347}
7348
7349impl sum_tree::ContextLessSummary for DiffTransformSummary {
7350    fn zero() -> Self {
7351        DiffTransformSummary {
7352            input: MBTextSummary::default(),
7353            output: MBTextSummary::default(),
7354        }
7355    }
7356
7357    fn add_summary(&mut self, other: &Self) {
7358        self.input += other.input;
7359        self.output += other.output;
7360    }
7361}
7362
7363impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7364    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7365        PathKey::min()
7366    }
7367
7368    fn add_summary(
7369        &mut self,
7370        summary: &'_ ExcerptSummary,
7371        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7372    ) {
7373        *self = summary.path_key.clone();
7374    }
7375}
7376
7377impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7378    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7379        MultiBufferOffset::ZERO
7380    }
7381
7382    fn add_summary(
7383        &mut self,
7384        summary: &'_ ExcerptSummary,
7385        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7386    ) {
7387        self += summary.text.len
7388    }
7389}
7390
7391impl sum_tree::ContextLessSummary for ExcerptSummary {
7392    fn zero() -> Self {
7393        Self::min()
7394    }
7395
7396    fn add_summary(&mut self, summary: &Self) {
7397        debug_assert!(
7398            summary.path_key >= self.path_key,
7399            "Path keys must be in ascending order: {:?} > {:?}",
7400            summary.path_key,
7401            self.path_key
7402        );
7403
7404        self.path_key = summary.path_key.clone();
7405        self.max_anchor = summary.max_anchor;
7406        self.text += summary.text;
7407        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7408        self.count += summary.count;
7409    }
7410}
7411
7412impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7413    fn cmp(
7414        &self,
7415        cursor_location: &ExcerptSummary,
7416        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7417    ) -> cmp::Ordering {
7418        match self {
7419            AnchorSeekTarget::Min => Ordering::Less,
7420            AnchorSeekTarget::Max => Ordering::Greater,
7421            AnchorSeekTarget::Excerpt {
7422                path_key,
7423                anchor,
7424                snapshot,
7425            } => {
7426                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7427                if path_comparison.is_ne() {
7428                    path_comparison
7429                } else if let Some(snapshot) = snapshot {
7430                    snapshot
7431                        .remote_id()
7432                        .cmp(&cursor_location.buffer_id)
7433                        .then_with(|| {
7434                            anchor
7435                                .text_anchor()
7436                                .cmp(&cursor_location.max_anchor, snapshot)
7437                        })
7438                } else {
7439                    // shouldn't happen because we expect this buffer not to have any excerpts
7440                    // (otherwise snapshot would have been Some)
7441                    Ordering::Equal
7442                }
7443            }
7444        }
7445    }
7446}
7447
7448impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7449    fn cmp(
7450        &self,
7451        cursor_location: &ExcerptSummary,
7452        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7453    ) -> cmp::Ordering {
7454        todo!()
7455    }
7456}
7457
7458impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7459where
7460    MBD: MultiBufferDimension + Default,
7461{
7462    fn zero(_: ()) -> Self {
7463        ExcerptDimension(MBD::default())
7464    }
7465
7466    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7467        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7468    }
7469}
7470
7471#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7472struct OutputDimension<T>(T);
7473
7474impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7475    fn eq(&self, other: &T) -> bool {
7476        self.0 == *other
7477    }
7478}
7479
7480impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7481    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7482        self.0.partial_cmp(other)
7483    }
7484}
7485
7486impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7487where
7488    T: ops::Sub<U, Output = R>,
7489{
7490    type Output = R;
7491
7492    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7493        self.0 - other.0
7494    }
7495}
7496
7497impl<R, T, U> ops::Add<U> for OutputDimension<T>
7498where
7499    T: ops::Add<U, Output = R>,
7500{
7501    type Output = OutputDimension<R>;
7502
7503    fn add(self, other: U) -> Self::Output {
7504        OutputDimension(self.0 + other)
7505    }
7506}
7507
7508impl<T, U> AddAssign<U> for OutputDimension<T>
7509where
7510    T: AddAssign<U>,
7511{
7512    fn add_assign(&mut self, other: U) {
7513        self.0 += other;
7514    }
7515}
7516
7517impl<T, U> SubAssign<U> for OutputDimension<T>
7518where
7519    T: SubAssign<U>,
7520{
7521    fn sub_assign(&mut self, other: U) {
7522        self.0 -= other;
7523    }
7524}
7525
7526#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7527struct ExcerptDimension<T>(T);
7528
7529impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7530    fn eq(&self, other: &T) -> bool {
7531        self.0 == *other
7532    }
7533}
7534
7535impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7536    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7537        self.0.partial_cmp(other)
7538    }
7539}
7540
7541impl ExcerptOffset {
7542    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7543        self.0.saturating_sub(other.0)
7544    }
7545}
7546
7547impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7548where
7549    T: ops::Sub<U, Output = R>,
7550{
7551    type Output = R;
7552
7553    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7554        self.0 - other.0
7555    }
7556}
7557
7558impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7559where
7560    T: ops::Add<U, Output = R>,
7561{
7562    type Output = ExcerptDimension<R>;
7563
7564    fn add(self, other: U) -> Self::Output {
7565        ExcerptDimension(self.0 + other)
7566    }
7567}
7568
7569impl<T, U> AddAssign<U> for ExcerptDimension<T>
7570where
7571    T: AddAssign<U>,
7572{
7573    fn add_assign(&mut self, other: U) {
7574        self.0 += other;
7575    }
7576}
7577
7578impl<T, U> SubAssign<U> for ExcerptDimension<T>
7579where
7580    T: SubAssign<U>,
7581{
7582    fn sub_assign(&mut self, other: U) {
7583        self.0 -= other;
7584    }
7585}
7586
7587impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7588    fn zero(_: ()) -> Self {
7589        MultiBufferOffset::ZERO
7590    }
7591
7592    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7593        *self += summary.output.len;
7594    }
7595}
7596
7597impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7598    for ExcerptDimension<MBD>
7599where
7600    MBD: MultiBufferDimension + Ord,
7601{
7602    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7603        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7604    }
7605}
7606
7607impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7608    for ExcerptDimension<MBD>
7609where
7610    MBD: MultiBufferDimension + Ord,
7611{
7612    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7613        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7614    }
7615}
7616
7617impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7618    for ExcerptDimension<MBD>
7619{
7620    fn zero(_: ()) -> Self {
7621        ExcerptDimension(MBD::default())
7622    }
7623
7624    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7625        self.0.add_mb_text_summary(&summary.input)
7626    }
7627}
7628
7629impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7630    for OutputDimension<MBD>
7631where
7632    MBD: MultiBufferDimension + Ord,
7633{
7634    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7635        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7636    }
7637}
7638
7639impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7640    for OutputDimension<MBD>
7641{
7642    fn zero(_: ()) -> Self {
7643        OutputDimension(MBD::default())
7644    }
7645
7646    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7647        self.0.add_mb_text_summary(&summary.output)
7648    }
7649}
7650
7651impl MultiBufferRows<'_> {
7652    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7653        self.point = Point::new(row, 0);
7654        self.cursor.seek(&self.point);
7655    }
7656}
7657
7658impl Iterator for MultiBufferRows<'_> {
7659    type Item = RowInfo;
7660
7661    fn next(&mut self) -> Option<Self::Item> {
7662        if self.is_empty && self.point.row == 0 {
7663            self.point += Point::new(1, 0);
7664            return Some(RowInfo {
7665                buffer_id: None,
7666                buffer_row: Some(0),
7667                multibuffer_row: Some(MultiBufferRow(0)),
7668                diff_status: None,
7669                expand_info: None,
7670                wrapped_buffer_row: None,
7671            });
7672        }
7673
7674        let mut region = self.cursor.region()?.clone();
7675        while self.point >= region.range.end {
7676            self.cursor.next();
7677            if let Some(next_region) = self.cursor.region() {
7678                region = next_region.clone();
7679            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7680                let multibuffer_row = MultiBufferRow(self.point.row);
7681                let last_excerpt = self
7682                    .cursor
7683                    .excerpts
7684                    .item()
7685                    .or(self.cursor.excerpts.prev_item())?;
7686                let last_row = last_excerpt
7687                    .range
7688                    .context
7689                    .end
7690                    .to_point(&last_excerpt.buffer)
7691                    .row;
7692
7693                let first_row = last_excerpt
7694                    .range
7695                    .context
7696                    .start
7697                    .to_point(&last_excerpt.buffer)
7698                    .row;
7699
7700                let expand_info = if self.is_singleton {
7701                    None
7702                } else {
7703                    let needs_expand_up = first_row == last_row
7704                        && last_row > 0
7705                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7706                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7707
7708                    if needs_expand_up && needs_expand_down {
7709                        Some(ExpandExcerptDirection::UpAndDown)
7710                    } else if needs_expand_up {
7711                        Some(ExpandExcerptDirection::Up)
7712                    } else if needs_expand_down {
7713                        Some(ExpandExcerptDirection::Down)
7714                    } else {
7715                        None
7716                    }
7717                    .map(|direction| ExpandInfo {
7718                        direction,
7719                        excerpt_id: last_excerpt.id,
7720                    })
7721                };
7722                self.point += Point::new(1, 0);
7723                return Some(RowInfo {
7724                    buffer_id: Some(last_excerpt.buffer_id),
7725                    buffer_row: Some(last_row),
7726                    multibuffer_row: Some(multibuffer_row),
7727                    diff_status: None,
7728                    wrapped_buffer_row: None,
7729                    expand_info,
7730                });
7731            } else {
7732                return None;
7733            };
7734        }
7735
7736        let overshoot = self.point - region.range.start;
7737        let buffer_point = region.buffer_range.start + overshoot;
7738        let expand_info = if self.is_singleton {
7739            None
7740        } else {
7741            let needs_expand_up = self.point.row == region.range.start.row
7742                && self.cursor.is_at_start_of_excerpt()
7743                && buffer_point.row > 0;
7744            let needs_expand_down = (region.excerpt.has_trailing_newline
7745                && self.point.row + 1 == region.range.end.row
7746                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7747                && self.cursor.is_at_end_of_excerpt()
7748                && buffer_point.row < region.buffer.max_point().row;
7749
7750            if needs_expand_up && needs_expand_down {
7751                Some(ExpandExcerptDirection::UpAndDown)
7752            } else if needs_expand_up {
7753                Some(ExpandExcerptDirection::Up)
7754            } else if needs_expand_down {
7755                Some(ExpandExcerptDirection::Down)
7756            } else {
7757                None
7758            }
7759            .map(|direction| ExpandInfo {
7760                direction,
7761                excerpt_id: region.excerpt.id,
7762            })
7763        };
7764
7765        let result = Some(RowInfo {
7766            buffer_id: Some(region.buffer.remote_id()),
7767            buffer_row: Some(buffer_point.row),
7768            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7769            diff_status: region
7770                .diff_hunk_status
7771                .filter(|_| self.point < region.range.end),
7772            expand_info,
7773            wrapped_buffer_row: None,
7774        });
7775        self.point += Point::new(1, 0);
7776        result
7777    }
7778}
7779
7780impl<'a> MultiBufferChunks<'a> {
7781    pub fn offset(&self) -> MultiBufferOffset {
7782        self.range.start
7783    }
7784
7785    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7786        self.diff_transforms.seek(&range.end, Bias::Right);
7787        let mut excerpt_end = self.diff_transforms.start().1;
7788        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7789            let overshoot = range.end - self.diff_transforms.start().0;
7790            excerpt_end += overshoot;
7791        }
7792
7793        self.diff_transforms.seek(&range.start, Bias::Right);
7794        let mut excerpt_start = self.diff_transforms.start().1;
7795        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7796            let overshoot = range.start - self.diff_transforms.start().0;
7797            excerpt_start += overshoot;
7798        }
7799
7800        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7801        self.buffer_chunk.take();
7802        self.range = range;
7803    }
7804
7805    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7806        self.excerpt_offset_range = new_range.clone();
7807        self.excerpts.seek(&new_range.start, Bias::Right);
7808        if let Some(excerpt) = self.excerpts.item() {
7809            let excerpt_start = *self.excerpts.start();
7810            if let Some(excerpt_chunks) = self
7811                .excerpt_chunks
7812                .as_mut()
7813                .filter(|chunks| excerpt.end_anchor() == chunks.end)
7814            {
7815                excerpt.seek_chunks(
7816                    excerpt_chunks,
7817                    (self.excerpt_offset_range.start - excerpt_start)
7818                        ..(self.excerpt_offset_range.end - excerpt_start),
7819                );
7820            } else {
7821                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7822                    (self.excerpt_offset_range.start - excerpt_start)
7823                        ..(self.excerpt_offset_range.end - excerpt_start),
7824                    self.language_aware,
7825                ));
7826            }
7827        } else {
7828            self.excerpt_chunks = None;
7829        }
7830    }
7831
7832    #[ztracing::instrument(skip_all)]
7833    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7834        loop {
7835            if self.excerpt_offset_range.is_empty() {
7836                return None;
7837            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7838                self.excerpt_offset_range.start += chunk.text.len();
7839                return Some(chunk);
7840            } else {
7841                self.excerpts.next();
7842                let excerpt = self.excerpts.item()?;
7843                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7844                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7845                    self.language_aware,
7846                ));
7847            }
7848        }
7849    }
7850}
7851
7852impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7853    type Item = &'a str;
7854
7855    fn next(&mut self) -> Option<Self::Item> {
7856        let mut region = self.cursor.region()?;
7857        if self.offset == region.range.start {
7858            self.cursor.prev();
7859            region = self.cursor.region()?;
7860            let start_overshoot = self.start.saturating_sub(region.range.start);
7861            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7862                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7863            ));
7864        }
7865
7866        if self.offset == region.range.end && region.has_trailing_newline {
7867            self.offset -= 1;
7868            Some("\n")
7869        } else {
7870            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7871            self.offset -= chunk.len();
7872            Some(chunk)
7873        }
7874    }
7875}
7876
7877impl<'a> Iterator for MultiBufferChunks<'a> {
7878    type Item = Chunk<'a>;
7879
7880    #[ztracing::instrument(skip_all)]
7881    fn next(&mut self) -> Option<Chunk<'a>> {
7882        if self.range.start >= self.range.end {
7883            return None;
7884        }
7885        if self.range.start == self.diff_transforms.end().0 {
7886            self.diff_transforms.next();
7887        }
7888
7889        let diff_transform_start = self.diff_transforms.start().0;
7890        let diff_transform_end = self.diff_transforms.end().0;
7891        debug_assert!(
7892            self.range.start < diff_transform_end,
7893            "{:?} < {:?} of ({1:?}..{2:?})",
7894            self.range.start,
7895            diff_transform_end,
7896            diff_transform_start
7897        );
7898
7899        let diff_transform = self.diff_transforms.item()?;
7900        match diff_transform {
7901            DiffTransform::BufferContent { .. } => {
7902                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7903                    chunk
7904                } else {
7905                    let chunk = self.next_excerpt_chunk().unwrap();
7906                    self.buffer_chunk.insert(chunk)
7907                };
7908
7909                let chunk_end = self.range.start + chunk.text.len();
7910                let diff_transform_end = diff_transform_end.min(self.range.end);
7911
7912                if diff_transform_end < chunk_end {
7913                    let split_idx = diff_transform_end - self.range.start;
7914                    let (before, after) = chunk.text.split_at(split_idx);
7915                    self.range.start = diff_transform_end;
7916                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7917                    let chars = chunk.chars & mask;
7918                    let tabs = chunk.tabs & mask;
7919                    let newlines = chunk.newlines & mask;
7920
7921                    chunk.text = after;
7922                    chunk.chars = chunk.chars >> split_idx;
7923                    chunk.tabs = chunk.tabs >> split_idx;
7924                    chunk.newlines = chunk.newlines >> split_idx;
7925
7926                    Some(Chunk {
7927                        text: before,
7928                        chars,
7929                        tabs,
7930                        newlines,
7931                        ..chunk.clone()
7932                    })
7933                } else {
7934                    self.range.start = chunk_end;
7935                    self.buffer_chunk.take()
7936                }
7937            }
7938            DiffTransform::DeletedHunk {
7939                buffer_id,
7940                base_text_byte_range,
7941                has_trailing_newline,
7942                ..
7943            } => {
7944                let base_text_start =
7945                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7946                let base_text_end =
7947                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7948                let base_text_end = base_text_end.min(base_text_byte_range.end);
7949
7950                let mut chunks = if let Some((_, mut chunks)) = self
7951                    .diff_base_chunks
7952                    .take()
7953                    .filter(|(id, _)| id == buffer_id)
7954                {
7955                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7956                    {
7957                        chunks.seek(base_text_start..base_text_end);
7958                    }
7959                    chunks
7960                } else {
7961                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7962                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7963                };
7964
7965                let chunk = if let Some(chunk) = chunks.next() {
7966                    self.range.start += chunk.text.len();
7967                    self.diff_base_chunks = Some((*buffer_id, chunks));
7968                    chunk
7969                } else {
7970                    debug_assert!(has_trailing_newline);
7971                    self.range.start += "\n".len();
7972                    Chunk {
7973                        text: "\n",
7974                        chars: 1u128,
7975                        newlines: 1u128,
7976                        ..Default::default()
7977                    }
7978                };
7979                Some(chunk)
7980            }
7981        }
7982    }
7983}
7984
7985impl MultiBufferBytes<'_> {
7986    fn consume(&mut self, len: usize) {
7987        self.range.start += len;
7988        self.chunk = &self.chunk[len..];
7989
7990        if !self.range.is_empty() && self.chunk.is_empty() {
7991            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7992                self.chunk = chunk;
7993            } else if self.has_trailing_newline {
7994                self.has_trailing_newline = false;
7995                self.chunk = b"\n";
7996            } else {
7997                self.cursor.next();
7998                if let Some(region) = self.cursor.region() {
7999                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8000                        region.buffer_range.start
8001                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8002                                .min(region.buffer_range.end),
8003                    );
8004                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8005                    self.excerpt_bytes = Some(excerpt_bytes);
8006                    self.has_trailing_newline =
8007                        region.has_trailing_newline && self.range.end >= region.range.end;
8008                    if self.chunk.is_empty() && self.has_trailing_newline {
8009                        self.has_trailing_newline = false;
8010                        self.chunk = b"\n";
8011                    }
8012                }
8013            }
8014        }
8015    }
8016}
8017
8018impl<'a> Iterator for MultiBufferBytes<'a> {
8019    type Item = &'a [u8];
8020
8021    fn next(&mut self) -> Option<Self::Item> {
8022        let chunk = self.chunk;
8023        if chunk.is_empty() {
8024            None
8025        } else {
8026            self.consume(chunk.len());
8027            Some(chunk)
8028        }
8029    }
8030}
8031
8032impl io::Read for MultiBufferBytes<'_> {
8033    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8034        let len = cmp::min(buf.len(), self.chunk.len());
8035        buf[..len].copy_from_slice(&self.chunk[..len]);
8036        if len > 0 {
8037            self.consume(len);
8038        }
8039        Ok(len)
8040    }
8041}
8042
8043impl io::Read for ReversedMultiBufferBytes<'_> {
8044    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8045        let len = cmp::min(buf.len(), self.chunk.len());
8046        buf[..len].copy_from_slice(&self.chunk[..len]);
8047        buf[..len].reverse();
8048        if len > 0 {
8049            self.range.end -= len;
8050            self.chunk = &self.chunk[..self.chunk.len() - len];
8051            if !self.range.is_empty()
8052                && self.chunk.is_empty()
8053                && let Some(chunk) = self.chunks.next()
8054            {
8055                self.chunk = chunk.as_bytes();
8056            }
8057        }
8058        Ok(len)
8059    }
8060}
8061
8062impl<'a> Iterator for ExcerptChunks<'a> {
8063    type Item = Chunk<'a>;
8064
8065    fn next(&mut self) -> Option<Self::Item> {
8066        if let Some(chunk) = self.content_chunks.next() {
8067            return Some(chunk);
8068        }
8069
8070        if self.has_footer {
8071            let text = "\n";
8072            let chars = 0b1;
8073            let newlines = 0b1;
8074            self.has_footer = false;
8075            return Some(Chunk {
8076                text,
8077                chars,
8078                newlines,
8079                ..Default::default()
8080            });
8081        }
8082
8083        None
8084    }
8085}
8086
8087impl ToOffset for Point {
8088    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8089        snapshot.point_to_offset(*self)
8090    }
8091    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8092        snapshot.point_to_offset_utf16(*self)
8093    }
8094}
8095
8096impl ToOffset for MultiBufferOffset {
8097    #[track_caller]
8098    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8099        assert!(
8100            *self <= snapshot.len(),
8101            "offset {} is greater than the snapshot.len() {}",
8102            self.0,
8103            snapshot.len().0,
8104        );
8105        *self
8106    }
8107    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8108        snapshot.offset_to_offset_utf16(*self)
8109    }
8110}
8111
8112impl ToOffset for MultiBufferOffsetUtf16 {
8113    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8114        snapshot.offset_utf16_to_offset(*self)
8115    }
8116
8117    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8118        *self
8119    }
8120}
8121
8122impl ToOffset for PointUtf16 {
8123    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8124        snapshot.point_utf16_to_offset(*self)
8125    }
8126    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8127        snapshot.point_utf16_to_offset_utf16(*self)
8128    }
8129}
8130
8131impl ToPoint for MultiBufferOffset {
8132    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8133        snapshot.offset_to_point(*self)
8134    }
8135    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8136        snapshot.offset_to_point_utf16(*self)
8137    }
8138}
8139
8140impl ToPoint for Point {
8141    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8142        *self
8143    }
8144    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8145        snapshot.point_to_point_utf16(*self)
8146    }
8147}
8148
8149impl ToPoint for PointUtf16 {
8150    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8151        snapshot.point_utf16_to_point(*self)
8152    }
8153    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8154        *self
8155    }
8156}
8157
8158#[cfg(debug_assertions)]
8159pub mod debug {
8160    use super::*;
8161
8162    pub trait ToMultiBufferDebugRanges {
8163        fn to_multi_buffer_debug_ranges(
8164            &self,
8165            snapshot: &MultiBufferSnapshot,
8166        ) -> Vec<Range<MultiBufferOffset>>;
8167    }
8168
8169    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8170        fn to_multi_buffer_debug_ranges(
8171            &self,
8172            snapshot: &MultiBufferSnapshot,
8173        ) -> Vec<Range<MultiBufferOffset>> {
8174            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8175        }
8176    }
8177
8178    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8179        fn to_multi_buffer_debug_ranges(
8180            &self,
8181            snapshot: &MultiBufferSnapshot,
8182        ) -> Vec<Range<MultiBufferOffset>> {
8183            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8184                .to_multi_buffer_debug_ranges(snapshot)
8185        }
8186    }
8187
8188    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8189        fn to_multi_buffer_debug_ranges(
8190            &self,
8191            snapshot: &MultiBufferSnapshot,
8192        ) -> Vec<Range<MultiBufferOffset>> {
8193            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8194        }
8195    }
8196
8197    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8198        fn to_multi_buffer_debug_ranges(
8199            &self,
8200            snapshot: &MultiBufferSnapshot,
8201        ) -> Vec<Range<MultiBufferOffset>> {
8202            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8203        }
8204    }
8205
8206    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8207        fn to_multi_buffer_debug_ranges(
8208            &self,
8209            snapshot: &MultiBufferSnapshot,
8210        ) -> Vec<Range<MultiBufferOffset>> {
8211            self.iter()
8212                .map(|item| {
8213                    let offset = item.to_offset(snapshot);
8214                    offset..offset
8215                })
8216                .collect()
8217        }
8218    }
8219
8220    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8221        fn to_multi_buffer_debug_ranges(
8222            &self,
8223            snapshot: &MultiBufferSnapshot,
8224        ) -> Vec<Range<MultiBufferOffset>> {
8225            self.iter()
8226                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8227                .collect()
8228        }
8229    }
8230}