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