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::{PathExcerptInsertResult, 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: PathKey,
 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;
 171type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 172type ExcerptPoint = ExcerptDimension<Point>;
 173
 174#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 175#[serde(transparent)]
 176pub struct MultiBufferRow(pub u32);
 177
 178impl MultiBufferRow {
 179    pub const MIN: Self = Self(0);
 180    pub const MAX: Self = Self(u32::MAX);
 181}
 182
 183impl ops::Add<usize> for MultiBufferRow {
 184    type Output = Self;
 185
 186    fn add(self, rhs: usize) -> Self::Output {
 187        MultiBufferRow(self.0 + rhs as u32)
 188    }
 189}
 190
 191pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 192    type TextDimension: TextDimension;
 193    fn from_summary(summary: &MBTextSummary) -> Self;
 194
 195    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 196
 197    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 198}
 199
 200// todo(lw): MultiBufferPoint
 201impl MultiBufferDimension for Point {
 202    type TextDimension = Point;
 203    fn from_summary(summary: &MBTextSummary) -> Self {
 204        summary.lines
 205    }
 206
 207    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 208        *self += *other;
 209    }
 210
 211    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 212        *self += summary.lines;
 213    }
 214}
 215
 216// todo(lw): MultiBufferPointUtf16
 217impl MultiBufferDimension for PointUtf16 {
 218    type TextDimension = PointUtf16;
 219    fn from_summary(summary: &MBTextSummary) -> Self {
 220        summary.lines_utf16()
 221    }
 222
 223    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 224        *self += *other;
 225    }
 226
 227    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 228        *self += summary.lines_utf16();
 229    }
 230}
 231
 232#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 233pub struct MultiBufferOffset(pub usize);
 234
 235impl fmt::Display for MultiBufferOffset {
 236    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 237        write!(f, "{}", self.0)
 238    }
 239}
 240
 241impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 242    type Sampler = MultiBufferOffsetUniformSampler;
 243}
 244
 245pub struct MultiBufferOffsetUniformSampler {
 246    sampler: rand::distr::uniform::UniformUsize,
 247}
 248
 249impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 250    type X = MultiBufferOffset;
 251
 252    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 253    where
 254        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 255        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256    {
 257        let low = *low_b.borrow();
 258        let high = *high_b.borrow();
 259        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 260        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 261    }
 262
 263    #[inline] // if the range is constant, this helps LLVM to do the
 264    // calculations at compile-time.
 265    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 266    where
 267        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 268        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269    {
 270        let low = *low_b.borrow();
 271        let high = *high_b.borrow();
 272        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 273        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 274    }
 275
 276    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 277        MultiBufferOffset(self.sampler.sample(rng))
 278    }
 279}
 280impl MultiBufferDimension for MultiBufferOffset {
 281    type TextDimension = usize;
 282    fn from_summary(summary: &MBTextSummary) -> Self {
 283        summary.len
 284    }
 285
 286    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 287        self.0 += *other;
 288    }
 289
 290    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 291        *self += summary.len;
 292    }
 293}
 294impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 295    type TextDimension = OffsetUtf16;
 296    fn from_summary(summary: &MBTextSummary) -> Self {
 297        MultiBufferOffsetUtf16(summary.len_utf16)
 298    }
 299
 300    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 301        self.0 += *other;
 302    }
 303
 304    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 305        self.0 += summary.len_utf16;
 306    }
 307}
 308
 309#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 310pub struct BufferOffset(pub usize);
 311
 312impl TextDimension for BufferOffset {
 313    fn from_text_summary(summary: &TextSummary) -> Self {
 314        BufferOffset(usize::from_text_summary(summary))
 315    }
 316    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 317        BufferOffset(usize::from_chunk(chunk))
 318    }
 319    fn add_assign(&mut self, other: &Self) {
 320        TextDimension::add_assign(&mut self.0, &other.0);
 321    }
 322}
 323impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 324    fn zero(cx: ()) -> Self {
 325        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 326    }
 327
 328    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 329        usize::add_summary(&mut self.0, summary, cx);
 330    }
 331}
 332
 333impl Sub for BufferOffset {
 334    type Output = usize;
 335
 336    fn sub(self, other: BufferOffset) -> Self::Output {
 337        self.0 - other.0
 338    }
 339}
 340
 341impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 342    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 343        self.0 += other.key;
 344    }
 345}
 346
 347impl language::ToPoint for BufferOffset {
 348    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 349        self.0.to_point(snapshot)
 350    }
 351}
 352
 353impl language::ToPointUtf16 for BufferOffset {
 354    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 355        self.0.to_point_utf16(snapshot)
 356    }
 357}
 358
 359impl language::ToOffset for BufferOffset {
 360    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 361        self.0.to_offset(snapshot)
 362    }
 363}
 364
 365impl language::ToOffsetUtf16 for BufferOffset {
 366    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 367        self.0.to_offset_utf16(snapshot)
 368    }
 369}
 370
 371#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 372pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 373
 374impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 375    type Output = MultiBufferOffsetUtf16;
 376
 377    fn add(self, rhs: usize) -> Self::Output {
 378        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 379    }
 380}
 381
 382impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 383    type Output = Self;
 384
 385    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 386        MultiBufferOffsetUtf16(self.0 + rhs)
 387    }
 388}
 389
 390impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 391    fn add_assign(&mut self, rhs: OffsetUtf16) {
 392        self.0 += rhs;
 393    }
 394}
 395
 396impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 397    fn add_assign(&mut self, rhs: usize) {
 398        self.0.0 += rhs;
 399    }
 400}
 401
 402impl Sub for MultiBufferOffsetUtf16 {
 403    type Output = OffsetUtf16;
 404
 405    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 406        self.0 - other.0
 407    }
 408}
 409
 410impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 411    type Output = MultiBufferOffsetUtf16;
 412
 413    fn sub(self, other: OffsetUtf16) -> Self::Output {
 414        MultiBufferOffsetUtf16(self.0 - other)
 415    }
 416}
 417
 418#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 419pub struct BufferOffsetUtf16(pub OffsetUtf16);
 420
 421impl MultiBufferOffset {
 422    const ZERO: Self = Self(0);
 423    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 424        self.0.saturating_sub(other.0)
 425    }
 426    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 427        MultiBufferOffset(self.0.saturating_sub(other))
 428    }
 429}
 430
 431impl ops::Sub for MultiBufferOffset {
 432    type Output = usize;
 433
 434    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 435        self.0 - other.0
 436    }
 437}
 438
 439impl ops::Sub<usize> for MultiBufferOffset {
 440    type Output = Self;
 441
 442    fn sub(self, other: usize) -> Self::Output {
 443        MultiBufferOffset(self.0 - other)
 444    }
 445}
 446
 447impl ops::SubAssign<usize> for MultiBufferOffset {
 448    fn sub_assign(&mut self, other: usize) {
 449        self.0 -= other;
 450    }
 451}
 452
 453impl ops::Add<usize> for BufferOffset {
 454    type Output = Self;
 455
 456    fn add(self, rhs: usize) -> Self::Output {
 457        BufferOffset(self.0 + rhs)
 458    }
 459}
 460
 461impl ops::AddAssign<usize> for BufferOffset {
 462    fn add_assign(&mut self, other: usize) {
 463        self.0 += other;
 464    }
 465}
 466
 467impl ops::Add<usize> for MultiBufferOffset {
 468    type Output = Self;
 469
 470    fn add(self, rhs: usize) -> Self::Output {
 471        MultiBufferOffset(self.0 + rhs)
 472    }
 473}
 474
 475impl ops::AddAssign<usize> for MultiBufferOffset {
 476    fn add_assign(&mut self, other: usize) {
 477        self.0 += other;
 478    }
 479}
 480
 481impl ops::Add<isize> for MultiBufferOffset {
 482    type Output = Self;
 483
 484    fn add(self, rhs: isize) -> Self::Output {
 485        MultiBufferOffset((self.0 as isize + rhs) as usize)
 486    }
 487}
 488
 489impl ops::Add for MultiBufferOffset {
 490    type Output = Self;
 491
 492    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 493        MultiBufferOffset(self.0 + rhs.0)
 494    }
 495}
 496
 497impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 498    fn add_assign(&mut self, other: MultiBufferOffset) {
 499        self.0 += other.0;
 500    }
 501}
 502
 503pub trait ToOffset: 'static + fmt::Debug {
 504    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 505    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 506}
 507
 508pub trait ToPoint: 'static + fmt::Debug {
 509    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 510    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 511}
 512
 513struct BufferState {
 514    buffer: Entity<Buffer>,
 515    last_version: RefCell<clock::Global>,
 516    last_non_text_state_update_count: Cell<usize>,
 517    _subscriptions: [gpui::Subscription; 2],
 518}
 519
 520struct DiffState {
 521    diff: Entity<BufferDiff>,
 522    main_buffer: Option<Entity<language::Buffer>>,
 523    _subscription: gpui::Subscription,
 524}
 525
 526impl DiffState {
 527    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 528        DiffStateSnapshot {
 529            diff: self.diff.read(cx).snapshot(cx),
 530            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 531        }
 532    }
 533}
 534
 535#[derive(Clone)]
 536struct DiffStateSnapshot {
 537    diff: BufferDiffSnapshot,
 538    main_buffer: Option<language::BufferSnapshot>,
 539}
 540
 541impl std::ops::Deref for DiffStateSnapshot {
 542    type Target = BufferDiffSnapshot;
 543
 544    fn deref(&self) -> &Self::Target {
 545        &self.diff
 546    }
 547}
 548
 549impl DiffState {
 550    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 551        DiffState {
 552            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 553                BufferDiffEvent::DiffChanged(DiffChanged {
 554                    changed_range,
 555                    base_text_changed_range: _,
 556                    extended_range,
 557                }) => {
 558                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 559                    let range = if use_extended {
 560                        extended_range.clone()
 561                    } else {
 562                        changed_range.clone()
 563                    };
 564                    if let Some(range) = range {
 565                        this.buffer_diff_changed(diff, range, cx)
 566                    }
 567                    cx.emit(Event::BufferDiffChanged);
 568                }
 569                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 570                _ => {}
 571            }),
 572            diff,
 573            main_buffer: None,
 574        }
 575    }
 576
 577    fn new_inverted(
 578        diff: Entity<BufferDiff>,
 579        main_buffer: Entity<language::Buffer>,
 580        cx: &mut Context<MultiBuffer>,
 581    ) -> Self {
 582        let weak_main_buffer = main_buffer.downgrade();
 583        DiffState {
 584            _subscription: cx.subscribe(&diff, {
 585                move |this, diff, event, cx| {
 586                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 587                        return;
 588                    };
 589                    match event {
 590                        BufferDiffEvent::DiffChanged(DiffChanged {
 591                            changed_range: _,
 592                            base_text_changed_range,
 593                            extended_range: _,
 594                        }) => {
 595                            this.inverted_buffer_diff_changed(
 596                                diff,
 597                                main_buffer,
 598                                base_text_changed_range.clone(),
 599                                cx,
 600                            );
 601                            cx.emit(Event::BufferDiffChanged);
 602                        }
 603                        BufferDiffEvent::LanguageChanged => {
 604                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 605                        }
 606                        _ => {}
 607                    }
 608                }
 609            }),
 610            diff,
 611            main_buffer: Some(main_buffer),
 612        }
 613    }
 614}
 615
 616/// The contents of a [`MultiBuffer`] at a single point in time.
 617#[derive(Clone, Default)]
 618pub struct MultiBufferSnapshot {
 619    excerpts: SumTree<Excerpt>,
 620    path_keys_by_buffer: TreeMap<BufferId, PathKey>,
 621    path_keys_by_index: TreeMap<PathKeyIndex, PathKey>,
 622    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 623    diff_transforms: SumTree<DiffTransform>,
 624    non_text_state_update_count: usize,
 625    edit_count: usize,
 626    is_dirty: bool,
 627    has_deleted_file: bool,
 628    has_conflict: bool,
 629    has_inverted_diff: bool,
 630    singleton: bool,
 631    trailing_excerpt_update_count: usize,
 632    all_diff_hunks_expanded: bool,
 633    show_deleted_hunks: bool,
 634    use_extended_diff_range: bool,
 635    show_headers: bool,
 636}
 637
 638#[derive(Debug, Clone)]
 639enum DiffTransform {
 640    BufferContent {
 641        summary: MBTextSummary,
 642        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 643    },
 644    DeletedHunk {
 645        summary: TextSummary,
 646        buffer_id: BufferId,
 647        hunk_info: DiffTransformHunkInfo,
 648        base_text_byte_range: Range<usize>,
 649        has_trailing_newline: bool,
 650    },
 651}
 652
 653#[derive(Clone, Copy, Debug)]
 654struct DiffTransformHunkInfo {
 655    buffer_id: BufferId,
 656    hunk_start_anchor: text::Anchor,
 657    hunk_secondary_status: DiffHunkSecondaryStatus,
 658    is_logically_deleted: bool,
 659    excerpt_end: ExcerptAnchor,
 660}
 661
 662impl Eq for DiffTransformHunkInfo {}
 663
 664impl PartialEq for DiffTransformHunkInfo {
 665    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 666        self.buffer_id == other.buffer_id && self.hunk_start_anchor == other.hunk_start_anchor
 667    }
 668}
 669
 670impl std::hash::Hash for DiffTransformHunkInfo {
 671    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 672        self.buffer_id.hash(state);
 673        self.hunk_start_anchor.hash(state);
 674    }
 675}
 676
 677#[derive(Clone)]
 678pub struct ExcerptBoundaryInfo {
 679    pub buffer: Arc<BufferSnapshot>,
 680    pub buffer_id: BufferId,
 681    pub range: ExcerptRange<text::Anchor>,
 682    pub end_row: MultiBufferRow,
 683}
 684
 685impl std::fmt::Debug for ExcerptBoundaryInfo {
 686    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 687        f.debug_struct(type_name::<Self>())
 688            .field("buffer_id", &self.buffer_id)
 689            .field("path", &self.buffer.file().map(|f| f.path()))
 690            .field("range", &self.range)
 691            .finish()
 692    }
 693}
 694
 695/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 696#[derive(Debug)]
 697pub struct ExcerptBoundary {
 698    pub prev: Option<ExcerptBoundaryInfo>,
 699    pub next: ExcerptBoundaryInfo,
 700    /// The row in the `MultiBuffer` where the boundary is located
 701    pub row: MultiBufferRow,
 702}
 703
 704impl ExcerptBoundary {
 705    pub fn starts_new_buffer(&self) -> bool {
 706        match (self.prev.as_ref(), &self.next) {
 707            (None, _) => true,
 708            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 709        }
 710    }
 711}
 712
 713#[derive(Clone, Debug, PartialEq, Eq)]
 714pub struct ExpandInfo {
 715    pub direction: ExpandExcerptDirection,
 716    pub excerpt_range: Range<text::Anchor>,
 717}
 718
 719#[derive(Clone, Debug, Default, PartialEq, Eq)]
 720pub struct RowInfo {
 721    pub buffer_id: Option<BufferId>,
 722    pub buffer_row: Option<u32>,
 723    pub multibuffer_row: Option<MultiBufferRow>,
 724    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 725    pub expand_info: Option<ExpandInfo>,
 726    pub wrapped_buffer_row: Option<u32>,
 727}
 728
 729/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 730#[derive(Clone)]
 731pub(crate) struct Excerpt {
 732    /// The location of the excerpt in the [`MultiBuffer`]
 733    pub(crate) path_key: PathKey,
 734    pub(crate) path_key_index: PathKeyIndex,
 735    /// A snapshot of the buffer being excerpted
 736    pub(crate) buffer: Arc<BufferSnapshot>,
 737    /// The range of the buffer to be shown in the excerpt
 738    pub(crate) range: ExcerptRange<text::Anchor>,
 739
 740    /// The last row in the excerpted slice of the buffer
 741    pub(crate) max_buffer_row: BufferRow,
 742    /// A summary of the text in the excerpt
 743    pub(crate) text_summary: TextSummary,
 744    pub(crate) has_trailing_newline: bool,
 745}
 746
 747/// A public view into an `Excerpt` in a [`MultiBuffer`].
 748///
 749/// Contains methods for getting the [`Buffer`] of the excerpt,
 750/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 751#[derive(Clone)]
 752pub struct MultiBufferExcerpt<'a> {
 753    excerpt: &'a Excerpt,
 754    diff_transforms:
 755        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 756    /// The offset in the multibuffer considering diff transforms.
 757    offset: MultiBufferOffset,
 758    /// The offset in the multibuffer without diff transforms.
 759    excerpt_offset: ExcerptOffset,
 760    buffer_offset: BufferOffset,
 761}
 762
 763/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 764/// These ranges are relative to the buffer itself
 765#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 766pub struct ExcerptRange<T> {
 767    /// The full range of text to be shown in the excerpt.
 768    pub context: Range<T>,
 769    /// The primary range of text to be highlighted in the excerpt.
 770    /// In a multi-buffer search, this would be the text that matched the search
 771    pub primary: Range<T>,
 772}
 773
 774impl<T: Clone> ExcerptRange<T> {
 775    pub fn new(context: Range<T>) -> Self {
 776        Self {
 777            context: context.clone(),
 778            primary: context,
 779        }
 780    }
 781}
 782
 783impl ExcerptRange<text::Anchor> {
 784    pub fn contains(&self, t: &text::Anchor, snapshot: &BufferSnapshot) -> bool {
 785        self.context.start.cmp(t, snapshot).is_le() && self.context.end.cmp(t, snapshot).is_ge()
 786    }
 787}
 788
 789#[derive(Clone, Debug)]
 790pub struct ExcerptSummary {
 791    path_key: PathKey,
 792    max_anchor: Anchor,
 793    widest_line_number: u32,
 794    text: MBTextSummary,
 795    count: usize,
 796}
 797
 798impl ExcerptSummary {
 799    pub fn min() -> Self {
 800        ExcerptSummary {
 801            path_key: PathKey::min(),
 802            max_anchor: Anchor::Min,
 803            widest_line_number: 0,
 804            text: MBTextSummary::default(),
 805            count: 0,
 806        }
 807    }
 808
 809    pub fn len(&self) -> ExcerptOffset {
 810        ExcerptDimension(self.text.len)
 811    }
 812}
 813
 814#[derive(Debug, Clone)]
 815pub struct DiffTransformSummary {
 816    input: MBTextSummary,
 817    output: MBTextSummary,
 818}
 819
 820/// Summary of a string of text.
 821#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 822pub struct MBTextSummary {
 823    /// Length in bytes.
 824    pub len: MultiBufferOffset,
 825    /// Length in UTF-8.
 826    pub chars: usize,
 827    /// Length in UTF-16 code units
 828    pub len_utf16: OffsetUtf16,
 829    /// A point representing the number of lines and the length of the last line.
 830    ///
 831    /// In other words, it marks the point after the last byte in the text, (if
 832    /// EOF was a character, this would be its position).
 833    pub lines: Point,
 834    /// How many `char`s are in the first line
 835    pub first_line_chars: u32,
 836    /// How many `char`s are in the last line
 837    pub last_line_chars: u32,
 838    /// How many UTF-16 code units are in the last line
 839    pub last_line_len_utf16: u32,
 840    /// The row idx of the longest row
 841    pub longest_row: u32,
 842    /// How many `char`s are in the longest row
 843    pub longest_row_chars: u32,
 844}
 845
 846impl From<TextSummary> for MBTextSummary {
 847    fn from(summary: TextSummary) -> Self {
 848        MBTextSummary {
 849            len: MultiBufferOffset(summary.len),
 850            chars: summary.chars,
 851            len_utf16: summary.len_utf16,
 852            lines: summary.lines,
 853            first_line_chars: summary.first_line_chars,
 854            last_line_chars: summary.last_line_chars,
 855            last_line_len_utf16: summary.last_line_len_utf16,
 856            longest_row: summary.longest_row,
 857            longest_row_chars: summary.longest_row_chars,
 858        }
 859    }
 860}
 861
 862impl From<MBTextSummary> for TextSummary {
 863    fn from(summary: MBTextSummary) -> Self {
 864        TextSummary {
 865            len: summary.len.0,
 866            chars: summary.chars,
 867            len_utf16: summary.len_utf16,
 868            lines: summary.lines,
 869            first_line_chars: summary.first_line_chars,
 870            last_line_chars: summary.last_line_chars,
 871            last_line_len_utf16: summary.last_line_len_utf16,
 872            longest_row: summary.longest_row,
 873            longest_row_chars: summary.longest_row_chars,
 874        }
 875    }
 876}
 877
 878impl From<&str> for MBTextSummary {
 879    fn from(text: &str) -> Self {
 880        MBTextSummary::from(TextSummary::from(text))
 881    }
 882}
 883
 884impl MultiBufferDimension for MBTextSummary {
 885    type TextDimension = TextSummary;
 886
 887    fn from_summary(summary: &MBTextSummary) -> Self {
 888        *summary
 889    }
 890
 891    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 892        *self += *summary;
 893    }
 894
 895    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 896        *self += *summary;
 897    }
 898}
 899
 900impl AddAssign for MBTextSummary {
 901    fn add_assign(&mut self, other: MBTextSummary) {
 902        let joined_chars = self.last_line_chars + other.first_line_chars;
 903        if joined_chars > self.longest_row_chars {
 904            self.longest_row = self.lines.row;
 905            self.longest_row_chars = joined_chars;
 906        }
 907        if other.longest_row_chars > self.longest_row_chars {
 908            self.longest_row = self.lines.row + other.longest_row;
 909            self.longest_row_chars = other.longest_row_chars;
 910        }
 911
 912        if self.lines.row == 0 {
 913            self.first_line_chars += other.first_line_chars;
 914        }
 915
 916        if other.lines.row == 0 {
 917            self.last_line_chars += other.first_line_chars;
 918            self.last_line_len_utf16 += other.last_line_len_utf16;
 919        } else {
 920            self.last_line_chars = other.last_line_chars;
 921            self.last_line_len_utf16 = other.last_line_len_utf16;
 922        }
 923
 924        self.chars += other.chars;
 925        self.len += other.len;
 926        self.len_utf16 += other.len_utf16;
 927        self.lines += other.lines;
 928    }
 929}
 930
 931impl AddAssign<TextSummary> for MBTextSummary {
 932    fn add_assign(&mut self, other: TextSummary) {
 933        *self += MBTextSummary::from(other);
 934    }
 935}
 936
 937impl MBTextSummary {
 938    pub fn lines_utf16(&self) -> PointUtf16 {
 939        PointUtf16 {
 940            row: self.lines.row,
 941            column: self.last_line_len_utf16,
 942        }
 943    }
 944}
 945
 946impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 947where
 948    K: MultiBufferDimension,
 949    V: MultiBufferDimension,
 950{
 951    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 952
 953    fn from_summary(summary: &MBTextSummary) -> Self {
 954        Self {
 955            key: K::from_summary(summary),
 956            value: Some(V::from_summary(summary)),
 957        }
 958    }
 959
 960    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 961        self.key.add_text_dim(&summary.key);
 962        if let Some(value) = &mut self.value {
 963            if let Some(other_value) = summary.value.as_ref() {
 964                value.add_text_dim(other_value);
 965            }
 966        }
 967    }
 968
 969    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 970        self.key.add_mb_text_summary(summary);
 971        if let Some(value) = &mut self.value {
 972            value.add_mb_text_summary(summary);
 973        }
 974    }
 975}
 976
 977#[derive(Clone)]
 978pub struct MultiBufferRows<'a> {
 979    point: Point,
 980    is_empty: bool,
 981    is_singleton: bool,
 982    cursor: MultiBufferCursor<'a, Point, Point>,
 983}
 984
 985pub struct MultiBufferChunks<'a> {
 986    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 987    diff_transforms:
 988        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 989    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 990    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 991    buffer_chunk: Option<Chunk<'a>>,
 992    range: Range<MultiBufferOffset>,
 993    excerpt_offset_range: Range<ExcerptOffset>,
 994    excerpt_chunks: Option<ExcerptChunks<'a>>,
 995    language_aware: bool,
 996}
 997
 998pub struct ReversedMultiBufferChunks<'a> {
 999    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1000    current_chunks: Option<rope::Chunks<'a>>,
1001    start: MultiBufferOffset,
1002    offset: MultiBufferOffset,
1003}
1004
1005pub struct MultiBufferBytes<'a> {
1006    range: Range<MultiBufferOffset>,
1007    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1008    excerpt_bytes: Option<text::Bytes<'a>>,
1009    has_trailing_newline: bool,
1010    chunk: &'a [u8],
1011}
1012
1013pub struct ReversedMultiBufferBytes<'a> {
1014    range: Range<MultiBufferOffset>,
1015    chunks: ReversedMultiBufferChunks<'a>,
1016    chunk: &'a [u8],
1017}
1018
1019#[derive(Clone)]
1020struct DiffTransforms<MBD> {
1021    output_dimension: OutputDimension<MBD>,
1022    excerpt_dimension: ExcerptDimension<MBD>,
1023}
1024
1025impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1026    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1027        Self {
1028            output_dimension: OutputDimension::zero(cx),
1029            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1030                cx,
1031            ),
1032        }
1033    }
1034
1035    fn add_summary(
1036        &mut self,
1037        summary: &'a DiffTransformSummary,
1038        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1039    ) {
1040        self.output_dimension.add_summary(summary, cx);
1041        self.excerpt_dimension.add_summary(summary, cx);
1042    }
1043}
1044
1045#[derive(Clone)]
1046struct MultiBufferCursor<'a, MBD, BD> {
1047    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1048    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1049    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1050    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1051}
1052
1053#[derive(Clone)]
1054struct MultiBufferRegion<'a, MBD, BD> {
1055    buffer: &'a BufferSnapshot,
1056    is_main_buffer: bool,
1057    diff_hunk_status: Option<DiffHunkStatus>,
1058    excerpt: &'a Excerpt,
1059    buffer_range: Range<BD>,
1060    range: Range<MBD>,
1061    has_trailing_newline: bool,
1062}
1063
1064struct ExcerptChunks<'a> {
1065    content_chunks: BufferChunks<'a>,
1066    end: ExcerptAnchor,
1067    has_footer: bool,
1068}
1069
1070#[derive(Debug)]
1071struct BufferEdit {
1072    range: Range<BufferOffset>,
1073    new_text: Arc<str>,
1074    is_insertion: bool,
1075    original_indent_column: Option<u32>,
1076}
1077
1078#[derive(Clone, Copy, Debug, PartialEq)]
1079enum DiffChangeKind {
1080    BufferEdited,
1081    DiffUpdated { base_changed: bool },
1082    ExpandOrCollapseHunks { expand: bool },
1083}
1084
1085#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1086pub enum ExpandExcerptDirection {
1087    Up,
1088    Down,
1089    UpAndDown,
1090}
1091
1092impl ExpandExcerptDirection {
1093    pub fn should_expand_up(&self) -> bool {
1094        match self {
1095            ExpandExcerptDirection::Up => true,
1096            ExpandExcerptDirection::Down => false,
1097            ExpandExcerptDirection::UpAndDown => true,
1098        }
1099    }
1100
1101    pub fn should_expand_down(&self) -> bool {
1102        match self {
1103            ExpandExcerptDirection::Up => false,
1104            ExpandExcerptDirection::Down => true,
1105            ExpandExcerptDirection::UpAndDown => true,
1106        }
1107    }
1108}
1109
1110#[derive(Clone, Debug, PartialEq)]
1111pub struct IndentGuide {
1112    pub buffer_id: BufferId,
1113    pub start_row: MultiBufferRow,
1114    pub end_row: MultiBufferRow,
1115    pub depth: u32,
1116    pub tab_size: u32,
1117    pub settings: IndentGuideSettings,
1118}
1119
1120impl IndentGuide {
1121    pub fn indent_level(&self) -> u32 {
1122        self.depth * self.tab_size
1123    }
1124}
1125
1126impl MultiBuffer {
1127    pub fn new(capability: Capability) -> Self {
1128        Self::new_(
1129            capability,
1130            MultiBufferSnapshot {
1131                show_headers: true,
1132                show_deleted_hunks: true,
1133                ..MultiBufferSnapshot::default()
1134            },
1135        )
1136    }
1137
1138    pub fn without_headers(capability: Capability) -> Self {
1139        Self::new_(
1140            capability,
1141            MultiBufferSnapshot {
1142                show_deleted_hunks: true,
1143                ..MultiBufferSnapshot::default()
1144            },
1145        )
1146    }
1147
1148    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1149        let mut this = Self::new_(
1150            buffer.read(cx).capability(),
1151            MultiBufferSnapshot {
1152                singleton: true,
1153                show_deleted_hunks: true,
1154                ..MultiBufferSnapshot::default()
1155            },
1156        );
1157        this.singleton = true;
1158        this.set_excerpts_for_path(
1159            PathKey::sorted(0),
1160            buffer.clone(),
1161            [Point::zero()..buffer.read(cx).max_point()],
1162            0,
1163            cx,
1164        );
1165        this
1166    }
1167
1168    #[inline]
1169    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1170        Self {
1171            snapshot: RefCell::new(snapshot),
1172            buffers: Default::default(),
1173            diffs: HashMap::default(),
1174            subscriptions: Topic::default(),
1175            singleton: false,
1176            capability,
1177            title: None,
1178            buffer_changed_since_sync: Default::default(),
1179            history: History::default(),
1180        }
1181    }
1182
1183    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1184        let mut buffers = BTreeMap::default();
1185        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1186        for (buffer_id, buffer_state) in self.buffers.iter() {
1187            buffer_state.buffer.update(new_cx, |buffer, _| {
1188                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1189            });
1190            buffers.insert(
1191                *buffer_id,
1192                BufferState {
1193                    buffer: buffer_state.buffer.clone(),
1194                    last_version: buffer_state.last_version.clone(),
1195                    last_non_text_state_update_count: buffer_state
1196                        .last_non_text_state_update_count
1197                        .clone(),
1198                    _subscriptions: [
1199                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1200                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1201                    ],
1202                },
1203            );
1204        }
1205        let mut diff_bases = HashMap::default();
1206        for (buffer_id, diff) in self.diffs.iter() {
1207            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1208        }
1209        Self {
1210            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1211            buffers,
1212            diffs: diff_bases,
1213            subscriptions: Default::default(),
1214            singleton: self.singleton,
1215            capability: self.capability,
1216            history: self.history.clone(),
1217            title: self.title.clone(),
1218            buffer_changed_since_sync,
1219        }
1220    }
1221
1222    pub fn set_group_interval(&mut self, group_interval: Duration) {
1223        self.history.set_group_interval(group_interval);
1224    }
1225
1226    pub fn with_title(mut self, title: String) -> Self {
1227        self.title = Some(title);
1228        self
1229    }
1230
1231    pub fn read_only(&self) -> bool {
1232        !self.capability.editable()
1233    }
1234
1235    pub fn capability(&self) -> Capability {
1236        self.capability
1237    }
1238
1239    /// Returns an up-to-date snapshot of the MultiBuffer.
1240    #[ztracing::instrument(skip_all)]
1241    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1242        self.sync(cx);
1243        self.snapshot.borrow().clone()
1244    }
1245
1246    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1247        self.sync(cx);
1248        self.snapshot.borrow()
1249    }
1250
1251    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1252        if self.singleton {
1253            Some(self.buffers.values().next().unwrap().buffer.clone())
1254        } else {
1255            None
1256        }
1257    }
1258
1259    pub fn is_singleton(&self) -> bool {
1260        self.singleton
1261    }
1262
1263    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1264        self.subscriptions.subscribe()
1265    }
1266
1267    pub fn is_dirty(&self, cx: &App) -> bool {
1268        self.read(cx).is_dirty()
1269    }
1270
1271    pub fn has_deleted_file(&self, cx: &App) -> bool {
1272        self.read(cx).has_deleted_file()
1273    }
1274
1275    pub fn has_conflict(&self, cx: &App) -> bool {
1276        self.read(cx).has_conflict()
1277    }
1278
1279    // The `is_empty` signature doesn't match what clippy expects
1280    #[allow(clippy::len_without_is_empty)]
1281    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1282        self.read(cx).len()
1283    }
1284
1285    pub fn is_empty(&self) -> bool {
1286        self.buffers.is_empty()
1287    }
1288
1289    pub fn edit<I, S, T>(
1290        &mut self,
1291        edits: I,
1292        autoindent_mode: Option<AutoindentMode>,
1293        cx: &mut Context<Self>,
1294    ) where
1295        I: IntoIterator<Item = (Range<S>, T)>,
1296        S: ToOffset,
1297        T: Into<Arc<str>>,
1298    {
1299        self.edit_internal(edits, autoindent_mode, true, cx);
1300    }
1301
1302    pub fn edit_non_coalesce<I, S, T>(
1303        &mut self,
1304        edits: I,
1305        autoindent_mode: Option<AutoindentMode>,
1306        cx: &mut Context<Self>,
1307    ) where
1308        I: IntoIterator<Item = (Range<S>, T)>,
1309        S: ToOffset,
1310        T: Into<Arc<str>>,
1311    {
1312        self.edit_internal(edits, autoindent_mode, false, cx);
1313    }
1314
1315    fn edit_internal<I, S, T>(
1316        &mut self,
1317        edits: I,
1318        autoindent_mode: Option<AutoindentMode>,
1319        coalesce_adjacent: bool,
1320        cx: &mut Context<Self>,
1321    ) where
1322        I: IntoIterator<Item = (Range<S>, T)>,
1323        S: ToOffset,
1324        T: Into<Arc<str>>,
1325    {
1326        if self.read_only() || self.buffers.is_empty() {
1327            return;
1328        }
1329        self.sync_mut(cx);
1330        let edits = edits
1331            .into_iter()
1332            .map(|(range, new_text)| {
1333                let mut range = range.start.to_offset(self.snapshot.get_mut())
1334                    ..range.end.to_offset(self.snapshot.get_mut());
1335                if range.start > range.end {
1336                    mem::swap(&mut range.start, &mut range.end);
1337                }
1338                (range, new_text.into())
1339            })
1340            .collect::<Vec<_>>();
1341
1342        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1343
1344        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1345        fn edit_internal(
1346            this: &mut MultiBuffer,
1347            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1348            mut autoindent_mode: Option<AutoindentMode>,
1349            coalesce_adjacent: bool,
1350            cx: &mut Context<MultiBuffer>,
1351        ) {
1352            let original_indent_columns = match &mut autoindent_mode {
1353                Some(AutoindentMode::Block {
1354                    original_indent_columns,
1355                }) => mem::take(original_indent_columns),
1356                _ => Default::default(),
1357            };
1358
1359            let buffer_edits = MultiBuffer::convert_edits_to_buffer_edits(
1360                edits,
1361                this.snapshot.get_mut(),
1362                &original_indent_columns,
1363            );
1364
1365            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1366            for (buffer_id, mut edits) in buffer_edits {
1367                buffer_ids.push(buffer_id);
1368                edits.sort_by_key(|edit| edit.range.start);
1369                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1370                    let mut edits = edits.into_iter().peekable();
1371                    let mut insertions = Vec::new();
1372                    let mut original_indent_columns = Vec::new();
1373                    let mut deletions = Vec::new();
1374                    let empty_str: Arc<str> = Arc::default();
1375                    while let Some(BufferEdit {
1376                        mut range,
1377                        mut new_text,
1378                        mut is_insertion,
1379                        original_indent_column,
1380                    }) = edits.next()
1381                    {
1382                        while let Some(BufferEdit {
1383                            range: next_range,
1384                            is_insertion: next_is_insertion,
1385                            new_text: next_new_text,
1386                            ..
1387                        }) = edits.peek()
1388                        {
1389                            let should_coalesce = if coalesce_adjacent {
1390                                range.end >= next_range.start
1391                            } else {
1392                                range.end > next_range.start
1393                            };
1394
1395                            if should_coalesce {
1396                                range.end = cmp::max(next_range.end, range.end);
1397                                is_insertion |= *next_is_insertion;
1398                                new_text = format!("{new_text}{next_new_text}").into();
1399                                edits.next();
1400                            } else {
1401                                break;
1402                            }
1403                        }
1404
1405                        if is_insertion {
1406                            original_indent_columns.push(original_indent_column);
1407                            insertions.push((
1408                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1409                                new_text.clone(),
1410                            ));
1411                        } else if !range.is_empty() {
1412                            deletions.push((
1413                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1414                                empty_str.clone(),
1415                            ));
1416                        }
1417                    }
1418
1419                    let deletion_autoindent_mode =
1420                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1421                            Some(AutoindentMode::Block {
1422                                original_indent_columns: Default::default(),
1423                            })
1424                        } else {
1425                            autoindent_mode.clone()
1426                        };
1427                    let insertion_autoindent_mode =
1428                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1429                            Some(AutoindentMode::Block {
1430                                original_indent_columns,
1431                            })
1432                        } else {
1433                            autoindent_mode.clone()
1434                        };
1435
1436                    if coalesce_adjacent {
1437                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1438                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1439                    } else {
1440                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1441                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1442                    }
1443                })
1444            }
1445
1446            cx.emit(Event::BuffersEdited { buffer_ids });
1447        }
1448    }
1449
1450    fn convert_edits_to_buffer_edits(
1451        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1452        snapshot: &MultiBufferSnapshot,
1453        original_indent_columns: &[Option<u32>],
1454    ) -> HashMap<BufferId, Vec<BufferEdit>> {
1455        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1456        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1457        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1458            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1459
1460            cursor.seek(&range.start);
1461            let mut start_region = cursor.region().expect("start offset out of bounds");
1462            if !start_region.is_main_buffer {
1463                cursor.next();
1464                if let Some(region) = cursor.region() {
1465                    start_region = region;
1466                } else {
1467                    continue;
1468                }
1469            }
1470
1471            if range.end < start_region.range.start {
1472                continue;
1473            }
1474
1475            let start_region = start_region.clone();
1476            if range.end > start_region.range.end {
1477                cursor.seek_forward(&range.end);
1478            }
1479            let mut end_region = cursor.region().expect("end offset out of bounds");
1480            if !end_region.is_main_buffer {
1481                cursor.prev();
1482                if let Some(region) = cursor.region() {
1483                    end_region = region;
1484                } else {
1485                    continue;
1486                }
1487            }
1488
1489            if range.start > end_region.range.end {
1490                continue;
1491            }
1492
1493            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1494            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1495            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1496                .min(start_region.buffer_range.end);
1497            let buffer_end =
1498                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1499
1500            if start_region.excerpt == end_region.excerpt {
1501                if start_region.buffer.capability == Capability::ReadWrite
1502                    && start_region.is_main_buffer
1503                {
1504                    buffer_edits
1505                        .entry(start_region.buffer.remote_id())
1506                        .or_default()
1507                        .push(BufferEdit {
1508                            range: buffer_start..buffer_end,
1509                            new_text,
1510                            is_insertion: true,
1511                            original_indent_column,
1512                        });
1513                }
1514            } else {
1515                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1516                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1517                if start_region.buffer.capability == Capability::ReadWrite
1518                    && start_region.is_main_buffer
1519                {
1520                    buffer_edits
1521                        .entry(start_region.buffer.remote_id())
1522                        .or_default()
1523                        .push(BufferEdit {
1524                            range: start_excerpt_range,
1525                            new_text: new_text.clone(),
1526                            is_insertion: true,
1527                            original_indent_column,
1528                        });
1529                }
1530                if end_region.buffer.capability == Capability::ReadWrite
1531                    && end_region.is_main_buffer
1532                {
1533                    buffer_edits
1534                        .entry(end_region.buffer.remote_id())
1535                        .or_default()
1536                        .push(BufferEdit {
1537                            range: end_excerpt_range,
1538                            new_text: new_text.clone(),
1539                            is_insertion: false,
1540                            original_indent_column,
1541                        });
1542                }
1543                let end_region_excerpt = end_region.excerpt.clone();
1544
1545                cursor.seek(&range.start);
1546                cursor.next_excerpt();
1547                while let Some(region) = cursor.region() {
1548                    if region.excerpt == &end_region_excerpt {
1549                        break;
1550                    }
1551                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1552                        buffer_edits
1553                            .entry(region.buffer.remote_id())
1554                            .or_default()
1555                            .push(BufferEdit {
1556                                range: region.buffer_range.clone(),
1557                                new_text: new_text.clone(),
1558                                is_insertion: false,
1559                                original_indent_column,
1560                            });
1561                    }
1562                    cursor.next_excerpt();
1563                }
1564            }
1565        }
1566        buffer_edits
1567    }
1568
1569    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1570    where
1571        I: IntoIterator<Item = Range<S>>,
1572        S: ToOffset,
1573    {
1574        if self.read_only() || self.buffers.is_empty() {
1575            return;
1576        }
1577        self.sync_mut(cx);
1578        let empty = Arc::<str>::from("");
1579        let edits = ranges
1580            .into_iter()
1581            .map(|range| {
1582                let mut range = range.start.to_offset(self.snapshot.get_mut())
1583                    ..range.end.to_offset(&self.snapshot.get_mut());
1584                if range.start > range.end {
1585                    mem::swap(&mut range.start, &mut range.end);
1586                }
1587                (range, empty.clone())
1588            })
1589            .collect::<Vec<_>>();
1590
1591        return autoindent_ranges_internal(self, edits, cx);
1592
1593        fn autoindent_ranges_internal(
1594            this: &mut MultiBuffer,
1595            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1596            cx: &mut Context<MultiBuffer>,
1597        ) {
1598            let buffer_edits =
1599                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1600
1601            let mut buffer_ids = Vec::new();
1602            for (buffer_id, mut edits) in buffer_edits {
1603                buffer_ids.push(buffer_id);
1604                edits.sort_unstable_by_key(|edit| edit.range.start);
1605
1606                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1607                for edit in edits {
1608                    if let Some(last_range) = ranges.last_mut()
1609                        && edit.range.start <= last_range.end
1610                    {
1611                        last_range.end = last_range.end.max(edit.range.end);
1612                        continue;
1613                    }
1614                    ranges.push(edit.range);
1615                }
1616
1617                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1618                    buffer.autoindent_ranges(ranges, cx);
1619                })
1620            }
1621
1622            cx.emit(Event::BuffersEdited { buffer_ids });
1623        }
1624    }
1625
1626    pub fn set_active_selections(
1627        &self,
1628        selections: &[Selection<Anchor>],
1629        line_mode: bool,
1630        cursor_shape: CursorShape,
1631        cx: &mut Context<Self>,
1632    ) {
1633        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1634            Default::default();
1635        let snapshot = self.read(cx);
1636        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(());
1637        for selection in selections {
1638            let start = selection.start.seek_target(&snapshot);
1639
1640            cursor.seek(&start, Bias::Left);
1641            while let Some(excerpt) = cursor.item() {
1642                // todo!() method?
1643                let excerpt_start =
1644                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.end);
1645                if excerpt_start.cmp(&selection.end, &snapshot).is_gt() {
1646                    break;
1647                }
1648                let start = text::Anchor::max(
1649                    &excerpt.range.context.start,
1650                    &selection.start.text_anchor().unwrap_or(text::Anchor::MIN),
1651                    &excerpt.buffer,
1652                )
1653                .clone();
1654                let end = text::Anchor::min(
1655                    &excerpt.range.context.end,
1656                    &selection.end.text_anchor().unwrap_or(text::Anchor::MAX),
1657                    &excerpt.buffer,
1658                )
1659                .clone();
1660                selections_by_buffer
1661                    .entry(excerpt.buffer.remote_id())
1662                    .or_default()
1663                    .push(Selection {
1664                        id: selection.id,
1665                        start,
1666                        end,
1667                        reversed: selection.reversed,
1668                        goal: selection.goal,
1669                    });
1670
1671                cursor.next();
1672            }
1673        }
1674
1675        for (buffer_id, buffer_state) in self.buffers.iter() {
1676            if !selections_by_buffer.contains_key(buffer_id) {
1677                buffer_state
1678                    .buffer
1679                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1680            }
1681        }
1682
1683        for (buffer_id, selections) in selections_by_buffer {
1684            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1685                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1686            });
1687        }
1688    }
1689
1690    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1691        for buffer in self.buffers.values() {
1692            buffer
1693                .buffer
1694                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1695        }
1696    }
1697
1698    #[instrument(skip_all)]
1699    fn merge_excerpt_ranges<'a>(
1700        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1701    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1702        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1703        let mut counts: Vec<usize> = Vec::new();
1704        for range in expanded_ranges {
1705            if let Some(last_range) = merged_ranges.last_mut() {
1706                assert!(
1707                    last_range.context.start <= range.context.start,
1708                    "ranges must be sorted: {last_range:?} <= {range:?}"
1709                );
1710                if last_range.context.end >= range.context.start
1711                    || last_range.context.end.row + 1 == range.context.start.row
1712                {
1713                    last_range.context.end = range.context.end.max(last_range.context.end);
1714                    *counts.last_mut().unwrap() += 1;
1715                    continue;
1716                }
1717            }
1718            merged_ranges.push(range.clone());
1719            counts.push(1);
1720        }
1721        (merged_ranges, counts)
1722    }
1723
1724    pub fn clear(&mut self, cx: &mut Context<Self>) {
1725        self.sync_mut(cx);
1726        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1727        let MultiBufferSnapshot {
1728            excerpts,
1729            diffs: _,
1730            diff_transforms: _,
1731            non_text_state_update_count: _,
1732            edit_count: _,
1733            is_dirty,
1734            has_deleted_file,
1735            has_conflict,
1736            has_inverted_diff,
1737            singleton: _,
1738            trailing_excerpt_update_count,
1739            all_diff_hunks_expanded: _,
1740            show_deleted_hunks: _,
1741            use_extended_diff_range: _,
1742            show_headers: _,
1743            path_keys_by_buffer: _,
1744            path_keys_by_index: _,
1745        } = self.snapshot.get_mut();
1746        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1747        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1748        *excerpts = Default::default();
1749        *trailing_excerpt_update_count += 1;
1750        *is_dirty = false;
1751        *has_deleted_file = false;
1752        *has_conflict = false;
1753        *has_inverted_diff = false;
1754
1755        let edits = Self::sync_diff_transforms(
1756            self.snapshot.get_mut(),
1757            vec![Edit {
1758                old: start..prev_len,
1759                new: start..start,
1760            }],
1761            DiffChangeKind::BufferEdited,
1762        );
1763        if !edits.is_empty() {
1764            self.subscriptions.publish(edits);
1765        }
1766        cx.emit(Event::Edited {
1767            edited_buffer: None,
1768        });
1769        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1770        cx.notify();
1771    }
1772
1773    #[ztracing::instrument(skip_all)]
1774    pub fn excerpts_for_buffer(
1775        &self,
1776        buffer_id: BufferId,
1777        cx: &App,
1778    ) -> Vec<ExcerptRange<text::Anchor>> {
1779        let mut excerpts = Vec::new();
1780        let snapshot = self.read(cx);
1781        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id).cloned() else {
1782            return excerpts;
1783        };
1784
1785        let mut cursor = snapshot.excerpts.cursor::<PathKey>(());
1786        cursor.seek_forward(&path_key, Bias::Left);
1787
1788        while let Some(item) = cursor.item()
1789            && item.path_key == path_key
1790        {
1791            excerpts.push(item.range.clone());
1792            cursor.next()
1793        }
1794        excerpts
1795    }
1796
1797    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1798        let snapshot = self.read(cx);
1799        let mut excerpts = snapshot
1800            .excerpts
1801            .cursor::<Dimensions<PathKey, ExcerptPoint>>(());
1802        let mut diff_transforms = snapshot
1803            .diff_transforms
1804            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1805        diff_transforms.next();
1806        let mut result = Vec::new();
1807        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id) else {
1808            return result;
1809        };
1810
1811        while let Some(excerpt) = excerpts.item()
1812            && &excerpt.path_key == path_key
1813        {
1814            let excerpt_start = excerpts.start().1;
1815            let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1816
1817            diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1818            let overshoot = excerpt_start - diff_transforms.start().0;
1819            let start = diff_transforms.start().1 + overshoot;
1820
1821            diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1822            let overshoot = excerpt_end - diff_transforms.start().0;
1823            let end = diff_transforms.start().1 + overshoot;
1824
1825            result.push(start.0..end.0);
1826            excerpts.next()
1827        }
1828        result
1829    }
1830
1831    // todo!() this seems bogus
1832    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1833        self.snapshot
1834            .borrow()
1835            .excerpts
1836            .iter()
1837            .map(|entry| entry.buffer.remote_id())
1838            .collect()
1839    }
1840
1841    pub fn excerpt_containing(&self, position: impl ToOffset, cx: &App) -> Option<ExcerptInfo> {
1842        let snapshot = self.read(cx);
1843        let offset = position.to_offset(&snapshot);
1844
1845        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1846        cursor.seek(&offset);
1847        let excerpt = cursor.excerpt().or(snapshot.excerpts.last())?;
1848        Some(ExcerptInfo {
1849            path_key: excerpt.path_key.clone(),
1850            buffer_id: excerpt.buffer.remote_id(),
1851            range: excerpt.range.clone(),
1852        })
1853    }
1854
1855    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1856        let buffer_id = match anchor {
1857            Anchor::Min => self.snapshot(cx).excerpts.first()?.buffer.remote_id(),
1858            Anchor::Max => self.snapshot(cx).excerpts.last()?.buffer.remote_id(),
1859            Anchor::Text { buffer_id, .. } => buffer_id,
1860        };
1861        self.buffer(buffer_id)
1862    }
1863
1864    // If point is at the end of the buffer, the last excerpt is returned
1865    pub fn point_to_buffer_offset<T: ToOffset>(
1866        &self,
1867        point: T,
1868        cx: &App,
1869    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1870        let snapshot = self.read(cx);
1871        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1872        Some((
1873            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1874            offset,
1875        ))
1876    }
1877
1878    // If point is at the end of the buffer, the last excerpt is returned
1879    pub fn point_to_buffer_point<T: ToPoint>(
1880        &self,
1881        point: T,
1882        cx: &App,
1883    ) -> Option<(Entity<Buffer>, Point)> {
1884        let snapshot = self.read(cx);
1885        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1886        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1887    }
1888
1889    pub fn buffer_point_to_anchor(
1890        &self,
1891        // todo(lw): We shouldn't need this?
1892        buffer: &Entity<Buffer>,
1893        point: Point,
1894        cx: &App,
1895    ) -> Option<Anchor> {
1896        let mut found = None;
1897        let snapshot = buffer.read(cx).snapshot();
1898        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1899            let start = range.context.start.to_point(&snapshot);
1900            let end = range.context.end.to_point(&snapshot);
1901            if start <= point && point < end {
1902                found = Some(snapshot.clip_point(point, Bias::Left));
1903                break;
1904            }
1905            if point < start {
1906                found = Some(start);
1907            }
1908            if point > end {
1909                found = Some(end);
1910            }
1911        }
1912
1913        Some(Anchor::text(snapshot.anchor_after(found?)))
1914    }
1915
1916    pub fn buffer_anchor_to_anchor(
1917        &self,
1918        // todo(lw): We shouldn't need this?
1919        buffer: &Entity<Buffer>,
1920        anchor: text::Anchor,
1921        cx: &App,
1922    ) -> Option<Anchor> {
1923        let snapshot = buffer.read(cx).snapshot();
1924        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1925            if range.contains(&anchor, &snapshot) {
1926                return Some(Anchor::text(anchor));
1927            }
1928        }
1929
1930        None
1931    }
1932
1933    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1934        &self,
1935        anchors: Anchors,
1936        cx: &mut Context<Self>,
1937    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1938        let mut error = None;
1939        let mut futures = Vec::new();
1940        for anchor in anchors {
1941            if let Some(excerpt_anchor) = anchor.excerpt_anchor() {
1942                if let Some(buffer) = self.buffers.get(&excerpt_anchor.buffer_id) {
1943                    buffer.buffer.update(cx, |buffer, _| {
1944                        futures.push(buffer.wait_for_anchors([excerpt_anchor.text_anchor()]))
1945                    });
1946                } else {
1947                    error = Some(anyhow!(
1948                        "buffer {:?} is not part of this multi-buffer",
1949                        excerpt_anchor.buffer_id
1950                    ));
1951                    break;
1952                }
1953            }
1954        }
1955        async move {
1956            if let Some(error) = error {
1957                Err(error)?;
1958            }
1959            for future in futures {
1960                future.await?;
1961            }
1962            Ok(())
1963        }
1964    }
1965
1966    pub fn text_anchor_for_position<T: ToOffset>(
1967        &self,
1968        position: T,
1969        cx: &App,
1970    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1971        let snapshot = self.read(cx);
1972        let anchor = snapshot.anchor_before(position).excerpt_anchor()?;
1973        let buffer = self.buffers.get(&anchor.buffer_id)?.buffer.clone();
1974        Some((buffer, anchor.text_anchor()))
1975    }
1976
1977    fn on_buffer_event(
1978        &mut self,
1979        buffer: Entity<Buffer>,
1980        event: &language::BufferEvent,
1981        cx: &mut Context<Self>,
1982    ) {
1983        use language::BufferEvent;
1984        let buffer_id = buffer.read(cx).remote_id();
1985        cx.emit(match event {
1986            BufferEvent::Edited => Event::Edited {
1987                edited_buffer: Some(buffer),
1988            },
1989            BufferEvent::DirtyChanged => Event::DirtyChanged,
1990            BufferEvent::Saved => Event::Saved,
1991            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1992            BufferEvent::Reloaded => Event::Reloaded,
1993            BufferEvent::LanguageChanged(has_language) => {
1994                Event::LanguageChanged(buffer_id, *has_language)
1995            }
1996            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1997            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1998            BufferEvent::CapabilityChanged => {
1999                self.capability = buffer.read(cx).capability();
2000                return;
2001            }
2002            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2003        });
2004    }
2005
2006    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2007        let diff = diff.read(cx);
2008        let buffer_id = diff.buffer_id;
2009        let diff = DiffStateSnapshot {
2010            diff: diff.snapshot(cx),
2011            main_buffer: None,
2012        };
2013        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2014    }
2015
2016    fn inverted_buffer_diff_language_changed(
2017        &mut self,
2018        diff: Entity<BufferDiff>,
2019        main_buffer: Entity<language::Buffer>,
2020        cx: &mut Context<Self>,
2021    ) {
2022        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2023        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2024        let diff = diff.read(cx);
2025        let diff = DiffStateSnapshot {
2026            diff: diff.snapshot(cx),
2027            main_buffer: Some(main_buffer_snapshot),
2028        };
2029        self.snapshot
2030            .get_mut()
2031            .diffs
2032            .insert(base_text_buffer_id, diff);
2033    }
2034
2035    fn buffer_diff_changed(
2036        &mut self,
2037        diff: Entity<BufferDiff>,
2038        range: Range<text::Anchor>,
2039        cx: &mut Context<Self>,
2040    ) {
2041        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2042            return;
2043        };
2044        let snapshot = self.sync_mut(cx);
2045
2046        let diff = diff.read(cx);
2047        let buffer_id = diff.buffer_id;
2048
2049        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2050            return;
2051        };
2052        let new_diff = DiffStateSnapshot {
2053            diff: diff.snapshot(cx),
2054            main_buffer: None,
2055        };
2056        let base_text_changed = snapshot
2057            .diffs
2058            .get(&buffer_id)
2059            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2060        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2061
2062        let buffer = buffer.read(cx);
2063        let diff_change_range = range.to_offset(buffer);
2064
2065        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2066        let edits = Self::sync_diff_transforms(
2067            snapshot,
2068            excerpt_edits,
2069            DiffChangeKind::DiffUpdated {
2070                base_changed: base_text_changed,
2071            },
2072        );
2073        if !edits.is_empty() {
2074            self.subscriptions.publish(edits);
2075        }
2076        cx.emit(Event::Edited {
2077            edited_buffer: None,
2078        });
2079    }
2080
2081    fn inverted_buffer_diff_changed(
2082        &mut self,
2083        diff: Entity<BufferDiff>,
2084        main_buffer: Entity<language::Buffer>,
2085        diff_change_range: Option<Range<usize>>,
2086        cx: &mut Context<Self>,
2087    ) {
2088        let snapshot = self.sync_mut(cx);
2089
2090        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2091        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2092            return;
2093        };
2094
2095        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2096        let diff = diff.read(cx);
2097        let new_diff = DiffStateSnapshot {
2098            diff: diff.snapshot(cx),
2099            main_buffer: Some(main_buffer_snapshot),
2100        };
2101        snapshot
2102            .diffs
2103            .insert_or_replace(base_text_buffer_id, new_diff);
2104
2105        let Some(diff_change_range) = diff_change_range else {
2106            return;
2107        };
2108
2109        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2110        let edits = Self::sync_diff_transforms(
2111            snapshot,
2112            excerpt_edits,
2113            DiffChangeKind::DiffUpdated {
2114                // We don't read this field for inverted diffs.
2115                base_changed: false,
2116            },
2117        );
2118        if !edits.is_empty() {
2119            self.subscriptions.publish(edits);
2120        }
2121        cx.emit(Event::Edited {
2122            edited_buffer: None,
2123        });
2124    }
2125
2126    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2127        self.buffers.values().map(|state| state.buffer.clone())
2128    }
2129
2130    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2131        self.all_buffers_iter().collect()
2132    }
2133
2134    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2135        self.buffers.keys().copied()
2136    }
2137
2138    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2139        self.all_buffer_ids_iter().collect()
2140    }
2141
2142    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2143        self.buffers
2144            .get(&buffer_id)
2145            .map(|state| state.buffer.clone())
2146    }
2147
2148    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2149        self.point_to_buffer_offset(point, cx)
2150            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2151    }
2152
2153    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2154        let buffer_id = self
2155            .snapshot
2156            .borrow()
2157            .excerpts
2158            .first()
2159            .map(|excerpt| excerpt.buffer.remote_id());
2160        buffer_id
2161            .and_then(|buffer_id| self.buffer(buffer_id))
2162            .map(|buffer| {
2163                let buffer = buffer.read(cx);
2164                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2165            })
2166            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2167    }
2168
2169    pub fn language_settings_at<'a, T: ToOffset>(
2170        &'a self,
2171        point: T,
2172        cx: &'a App,
2173    ) -> Cow<'a, LanguageSettings> {
2174        let mut language = None;
2175        let mut file = None;
2176        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2177            let buffer = buffer.read(cx);
2178            language = buffer.language_at(offset);
2179            file = buffer.file();
2180        }
2181        language_settings(language.map(|l| l.name()), file, cx)
2182    }
2183
2184    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2185        self.buffers.values().for_each(|state| f(&state.buffer))
2186    }
2187
2188    pub fn explicit_title(&self) -> Option<&str> {
2189        self.title.as_deref()
2190    }
2191
2192    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2193        if let Some(title) = self.title.as_ref() {
2194            return title.into();
2195        }
2196
2197        if let Some(buffer) = self.as_singleton() {
2198            let buffer = buffer.read(cx);
2199
2200            if let Some(file) = buffer.file() {
2201                return file.file_name(cx).into();
2202            }
2203
2204            if let Some(title) = self.buffer_content_title(buffer) {
2205                return title;
2206            }
2207        };
2208
2209        "untitled".into()
2210    }
2211
2212    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2213        let mut is_leading_whitespace = true;
2214        let mut count = 0;
2215        let mut prev_was_space = false;
2216        let mut title = String::new();
2217
2218        for ch in buffer.snapshot().chars() {
2219            if is_leading_whitespace && ch.is_whitespace() {
2220                continue;
2221            }
2222
2223            is_leading_whitespace = false;
2224
2225            if ch == '\n' || count >= 40 {
2226                break;
2227            }
2228
2229            if ch.is_whitespace() {
2230                if !prev_was_space {
2231                    title.push(' ');
2232                    count += 1;
2233                    prev_was_space = true;
2234                }
2235            } else {
2236                title.push(ch);
2237                count += 1;
2238                prev_was_space = false;
2239            }
2240        }
2241
2242        let title = title.trim_end().to_string();
2243
2244        if title.is_empty() {
2245            return None;
2246        }
2247
2248        Some(title.into())
2249    }
2250
2251    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2252        self.title = Some(title);
2253        cx.notify();
2254    }
2255
2256    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2257    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2258        for buffer_state in self.buffers.values() {
2259            buffer_state
2260                .buffer
2261                .update(cx, |buffer, _cx| buffer.refresh_preview());
2262        }
2263    }
2264
2265    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2266    pub fn preserve_preview(&self, cx: &App) -> bool {
2267        self.buffers
2268            .values()
2269            .all(|state| state.buffer.read(cx).preserve_preview())
2270    }
2271
2272    #[cfg(any(test, feature = "test-support"))]
2273    pub fn is_parsing(&self, cx: &App) -> bool {
2274        self.as_singleton().unwrap().read(cx).is_parsing()
2275    }
2276
2277    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2278        let buffer_id = diff.read(cx).buffer_id;
2279
2280        if let Some(existing_diff) = self.diff_for(buffer_id)
2281            && diff.entity_id() == existing_diff.entity_id()
2282        {
2283            return;
2284        }
2285
2286        self.buffer_diff_changed(
2287            diff.clone(),
2288            text::Anchor::min_max_range_for_buffer(buffer_id),
2289            cx,
2290        );
2291        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2292    }
2293
2294    pub fn add_inverted_diff(
2295        &mut self,
2296        diff: Entity<BufferDiff>,
2297        main_buffer: Entity<language::Buffer>,
2298        cx: &mut Context<Self>,
2299    ) {
2300        let snapshot = diff.read(cx).base_text(cx);
2301        let base_text_buffer_id = snapshot.remote_id();
2302        let diff_change_range = 0..snapshot.len();
2303        self.snapshot.get_mut().has_inverted_diff = true;
2304        self.inverted_buffer_diff_changed(
2305            diff.clone(),
2306            main_buffer.clone(),
2307            Some(diff_change_range),
2308            cx,
2309        );
2310        self.diffs.insert(
2311            base_text_buffer_id,
2312            DiffState::new_inverted(diff, main_buffer, cx),
2313        );
2314    }
2315
2316    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2317        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2318    }
2319
2320    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2321        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2322    }
2323
2324    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2325        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2326    }
2327
2328    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2329        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2330        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2331    }
2332
2333    pub fn all_diff_hunks_expanded(&self) -> bool {
2334        self.snapshot.borrow().all_diff_hunks_expanded
2335    }
2336
2337    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2338        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2339        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2340    }
2341
2342    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2343        self.snapshot.get_mut().show_deleted_hunks = show;
2344
2345        self.sync_mut(cx);
2346
2347        let old_len = self.snapshot.borrow().len();
2348
2349        let ranges = std::iter::once((Point::zero()..Point::MAX, Anchor::Max));
2350        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2351
2352        let new_len = self.snapshot.borrow().len();
2353
2354        self.subscriptions.publish(vec![Edit {
2355            old: MultiBufferOffset(0)..old_len,
2356            new: MultiBufferOffset(0)..new_len,
2357        }]);
2358
2359        cx.emit(Event::DiffHunksToggled);
2360        cx.emit(Event::Edited {
2361            edited_buffer: None,
2362        });
2363    }
2364
2365    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2366        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2367    }
2368
2369    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2370        self.read(cx)
2371            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2372            .nth(1)
2373            .is_some()
2374    }
2375
2376    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2377        let snapshot = self.read(cx);
2378        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2379        let offset_range = range.to_offset(&snapshot);
2380        cursor.seek(&offset_range.start, Bias::Left);
2381        while let Some(item) = cursor.item() {
2382            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2383                break;
2384            }
2385            if item.hunk_info().is_some() {
2386                return true;
2387            }
2388            cursor.next();
2389        }
2390        false
2391    }
2392
2393    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2394        let snapshot = self.read(cx);
2395        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2396        for range in ranges {
2397            let range = range.to_point(&snapshot);
2398            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2399            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2400                .min(snapshot.len());
2401            cursor.seek(&start, Bias::Right);
2402            while let Some(item) = cursor.item() {
2403                if *cursor.start() >= end {
2404                    break;
2405                }
2406                if item.hunk_info().is_some() {
2407                    return true;
2408                }
2409                cursor.next();
2410            }
2411        }
2412        false
2413    }
2414
2415    pub fn expand_or_collapse_diff_hunks_inner(
2416        &mut self,
2417        // second element is the end of the last excerpt that should be considered for this range
2418        // (or Anchor::Max to opt out)
2419        ranges: impl IntoIterator<Item = (Range<Point>, Anchor)>,
2420        expand: bool,
2421        cx: &mut Context<Self>,
2422    ) -> Vec<Edit<MultiBufferOffset>> {
2423        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2424            return Vec::new();
2425        }
2426        self.sync_mut(cx);
2427        let mut snapshot = self.snapshot.get_mut();
2428        let mut excerpt_edits = Vec::new();
2429        let mut last_hunk_row = None;
2430        for (range, excerpt_end) in ranges {
2431            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2432                if diff_hunk
2433                    .multi_buffer_range()
2434                    .end
2435                    .cmp(&excerpt_end, &snapshot)
2436                    .is_gt()
2437                {
2438                    continue;
2439                }
2440                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2441                    continue;
2442                }
2443                let range = diff_hunk.multi_buffer_range();
2444                let start = snapshot.excerpt_offset_for_anchor(&range.start);
2445                let end = snapshot.excerpt_offset_for_anchor(&range.end);
2446                last_hunk_row = Some(diff_hunk.row_range.start);
2447                excerpt_edits.push(text::Edit {
2448                    old: start..end,
2449                    new: start..end,
2450                });
2451            }
2452        }
2453
2454        Self::sync_diff_transforms(
2455            &mut snapshot,
2456            excerpt_edits,
2457            DiffChangeKind::ExpandOrCollapseHunks { expand },
2458        )
2459    }
2460
2461    pub fn expand_or_collapse_diff_hunks(
2462        &mut self,
2463        ranges: Vec<Range<Anchor>>,
2464        expand: bool,
2465        cx: &mut Context<Self>,
2466    ) {
2467        let snapshot = self.snapshot.borrow().clone();
2468        let ranges = ranges.iter().map(move |range| {
2469            let excerpt_end = snapshot
2470                .excerpt_at(range.end)
2471                .map(|excerpt| excerpt.end_anchor().into())
2472                .unwrap_or(Anchor::Max);
2473            let range = range.to_point(&snapshot);
2474            let mut peek_end = range.end;
2475            if range.end.row < snapshot.max_row().0 {
2476                peek_end = Point::new(range.end.row + 1, 0);
2477            };
2478            (range.start..peek_end, excerpt_end)
2479        });
2480        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2481        if !edits.is_empty() {
2482            self.subscriptions.publish(edits);
2483        }
2484        cx.emit(Event::DiffHunksToggled);
2485        cx.emit(Event::Edited {
2486            edited_buffer: None,
2487        });
2488    }
2489
2490    #[ztracing::instrument(skip_all)]
2491    fn sync(&self, cx: &App) {
2492        let changed = self.buffer_changed_since_sync.replace(false);
2493        if !changed {
2494            return;
2495        }
2496        let edits = Self::sync_from_buffer_changes(
2497            &mut self.snapshot.borrow_mut(),
2498            &self.buffers,
2499            &self.diffs,
2500            cx,
2501        );
2502        if !edits.is_empty() {
2503            self.subscriptions.publish(edits);
2504        }
2505    }
2506
2507    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2508        let snapshot = self.snapshot.get_mut();
2509        let changed = self.buffer_changed_since_sync.replace(false);
2510        if !changed {
2511            return snapshot;
2512        }
2513        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2514
2515        if !edits.is_empty() {
2516            self.subscriptions.publish(edits);
2517        }
2518
2519        snapshot
2520    }
2521
2522    fn sync_from_buffer_changes(
2523        snapshot: &mut MultiBufferSnapshot,
2524        buffers: &BTreeMap<BufferId, BufferState>,
2525        diffs: &HashMap<BufferId, DiffState>,
2526        cx: &App,
2527    ) -> Vec<Edit<MultiBufferOffset>> {
2528        let MultiBufferSnapshot {
2529            excerpts,
2530            diffs: buffer_diff,
2531            path_keys_by_buffer,
2532            path_keys_by_index,
2533            diff_transforms: _,
2534            non_text_state_update_count,
2535            edit_count,
2536            is_dirty,
2537            has_deleted_file,
2538            has_conflict,
2539            has_inverted_diff: _,
2540            singleton: _,
2541            trailing_excerpt_update_count: _,
2542            all_diff_hunks_expanded: _,
2543            show_deleted_hunks: _,
2544            use_extended_diff_range: _,
2545            show_headers: _,
2546        } = snapshot;
2547        *is_dirty = false;
2548        *has_deleted_file = false;
2549        *has_conflict = false;
2550
2551        if !diffs.is_empty() {
2552            let mut diffs_to_add = Vec::new();
2553            for (id, diff) in diffs {
2554                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2555                // and use the diff hunk base text ranges to compute diff transforms.
2556                // Those base text ranges are usize, so make sure if the base text changed
2557                // we also update the diff snapshot so that we don't use stale offsets
2558                if buffer_diff.get(id).is_none_or(|existing_diff| {
2559                    if existing_diff.main_buffer.is_none() {
2560                        return false;
2561                    }
2562                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2563                    base_text.remote_id() != existing_diff.base_text().remote_id()
2564                        || base_text
2565                            .version()
2566                            .changed_since(existing_diff.base_text().version())
2567                }) {
2568                    if diffs_to_add.capacity() == 0 {
2569                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2570                        // meaning re-allocations will be fairly expensive
2571                        diffs_to_add.reserve(diffs.len());
2572                    }
2573                    diffs_to_add.push((*id, diff.snapshot(cx)));
2574                }
2575            }
2576            buffer_diff.extend(diffs_to_add);
2577        }
2578
2579        let mut paths_to_edit = Vec::new();
2580        let mut non_text_state_updated = false;
2581        let mut edited = false;
2582        for buffer_state in buffers.values() {
2583            let buffer = buffer_state.buffer.read(cx);
2584            let version = buffer.version();
2585            let non_text_state_update_count = buffer.non_text_state_update_count();
2586
2587            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2588            let buffer_non_text_state_updated =
2589                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2590            if (buffer_edited || buffer_non_text_state_updated)
2591                && let Some(path_key) = path_keys_by_buffer.get(&buffer.remote_id())
2592            {
2593                *buffer_state.last_version.borrow_mut() = version;
2594                buffer_state
2595                    .last_non_text_state_update_count
2596                    .set(non_text_state_update_count);
2597                paths_to_edit.push((path_key.clone(), buffer_state.buffer.clone(), buffer_edited));
2598            }
2599
2600            edited |= buffer_edited;
2601            non_text_state_updated |= buffer_non_text_state_updated;
2602            *is_dirty |= buffer.is_dirty();
2603            *has_deleted_file |= buffer
2604                .file()
2605                .is_some_and(|file| file.disk_state().is_deleted());
2606            *has_conflict |= buffer.has_conflict();
2607        }
2608        if edited {
2609            *edit_count += 1;
2610        }
2611        if non_text_state_updated {
2612            *non_text_state_update_count += 1;
2613        }
2614
2615        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path);
2616
2617        let mut edits = Vec::new();
2618        let mut new_excerpts = SumTree::default();
2619        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2620
2621        for (path, buffer, buffer_edited) in paths_to_edit {
2622            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2623            let old_excerpt = cursor.item().unwrap();
2624            let buffer = buffer.read(cx);
2625            let buffer_id = buffer.remote_id();
2626            let mut new_excerpt;
2627            if buffer_edited {
2628                edits.extend(
2629                    buffer
2630                        .edits_since_in_range::<usize>(
2631                            old_excerpt.buffer.version(),
2632                            old_excerpt.range.context.clone(),
2633                        )
2634                        .map(|edit| {
2635                            let excerpt_old_start = cursor.start().1;
2636                            let excerpt_new_start =
2637                                ExcerptDimension(new_excerpts.summary().text.len);
2638                            let old_start = excerpt_old_start + edit.old.start;
2639                            let old_end = excerpt_old_start + edit.old.end;
2640                            let new_start = excerpt_new_start + edit.new.start;
2641                            let new_end = excerpt_new_start + edit.new.end;
2642                            Edit {
2643                                old: old_start..old_end,
2644                                new: new_start..new_end,
2645                            }
2646                        }),
2647                );
2648
2649                new_excerpt = Excerpt::new(
2650                    path,
2651                    Arc::new(buffer.snapshot()),
2652                    old_excerpt.range.clone(),
2653                    old_excerpt.has_trailing_newline,
2654                );
2655            } else {
2656                new_excerpt = old_excerpt.clone();
2657                new_excerpt.buffer = Arc::new(buffer.snapshot());
2658            }
2659
2660            new_excerpts.push(new_excerpt, ());
2661            cursor.next();
2662        }
2663        new_excerpts.append(cursor.suffix(), ());
2664
2665        drop(cursor);
2666        *excerpts = new_excerpts;
2667
2668        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2669    }
2670
2671    fn sync_diff_transforms(
2672        snapshot: &mut MultiBufferSnapshot,
2673        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2674        change_kind: DiffChangeKind,
2675    ) -> Vec<Edit<MultiBufferOffset>> {
2676        if excerpt_edits.is_empty() {
2677            return vec![];
2678        }
2679
2680        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2681        let mut old_diff_transforms = snapshot
2682            .diff_transforms
2683            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2684        let mut new_diff_transforms = SumTree::default();
2685        let mut old_expanded_hunks = HashSet::default();
2686        let mut output_edits = Vec::new();
2687        let mut output_delta = 0_isize;
2688        let mut at_transform_boundary = true;
2689        let mut end_of_current_insert = None;
2690
2691        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2692        while let Some(edit) = excerpt_edits.next() {
2693            excerpts.seek_forward(&edit.new.start, Bias::Right);
2694            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2695                excerpts.prev();
2696            }
2697
2698            // Keep any transforms that are before the edit.
2699            if at_transform_boundary {
2700                at_transform_boundary = false;
2701                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2702                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2703                if let Some(transform) = old_diff_transforms.item()
2704                    && old_diff_transforms.end().0 == edit.old.start
2705                    && old_diff_transforms.start().0 < edit.old.start
2706                {
2707                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2708                    old_diff_transforms.next();
2709                }
2710            }
2711
2712            // Compute the start of the edit in output coordinates.
2713            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2714            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2715            let edit_new_start =
2716                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2717
2718            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2719                &edit,
2720                &mut excerpts,
2721                &mut old_diff_transforms,
2722                &mut new_diff_transforms,
2723                &mut end_of_current_insert,
2724                &mut old_expanded_hunks,
2725                snapshot,
2726                change_kind,
2727            );
2728
2729            // Compute the end of the edit in output coordinates.
2730            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2731            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2732            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2733            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2734            let output_edit = Edit {
2735                old: edit_old_start..edit_old_end,
2736                new: edit_new_start..edit_new_end,
2737            };
2738
2739            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2740            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2741            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2742                output_edits.push(output_edit);
2743            }
2744
2745            // If this is the last edit that intersects the current diff transform,
2746            // then recreate the content up to the end of this transform, to prepare
2747            // for reusing additional slices of the old transforms.
2748            if excerpt_edits
2749                .peek()
2750                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2751            {
2752                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2753                    && match old_diff_transforms.item() {
2754                        Some(DiffTransform::BufferContent {
2755                            inserted_hunk_info: Some(hunk),
2756                            ..
2757                        }) => excerpts.item().is_some_and(|excerpt| {
2758                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2759                                && diff.main_buffer.is_some()
2760                            {
2761                                return true;
2762                            }
2763                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2764                        }),
2765                        _ => true,
2766                    };
2767
2768                let mut excerpt_offset = edit.new.end;
2769                if !keep_next_old_transform {
2770                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2771                    old_diff_transforms.next();
2772                }
2773
2774                old_expanded_hunks.clear();
2775                Self::push_buffer_content_transform(
2776                    snapshot,
2777                    &mut new_diff_transforms,
2778                    excerpt_offset,
2779                    end_of_current_insert,
2780                );
2781                at_transform_boundary = true;
2782            }
2783        }
2784
2785        // Keep any transforms that are after the last edit.
2786        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2787
2788        // Ensure there's always at least one buffer content transform.
2789        if new_diff_transforms.is_empty() {
2790            new_diff_transforms.push(
2791                DiffTransform::BufferContent {
2792                    summary: Default::default(),
2793                    inserted_hunk_info: None,
2794                },
2795                (),
2796            );
2797        }
2798
2799        drop(old_diff_transforms);
2800        drop(excerpts);
2801        snapshot.diff_transforms = new_diff_transforms;
2802        snapshot.edit_count += 1;
2803
2804        #[cfg(any(test, feature = "test-support"))]
2805        snapshot.check_invariants();
2806        output_edits
2807    }
2808
2809    fn recompute_diff_transforms_for_edit(
2810        edit: &Edit<ExcerptOffset>,
2811        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2812        old_diff_transforms: &mut Cursor<
2813            DiffTransform,
2814            Dimensions<ExcerptOffset, MultiBufferOffset>,
2815        >,
2816        new_diff_transforms: &mut SumTree<DiffTransform>,
2817        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2818        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2819        snapshot: &MultiBufferSnapshot,
2820        change_kind: DiffChangeKind,
2821    ) -> bool {
2822        log::trace!(
2823            "recomputing diff transform for edit {:?} => {:?}",
2824            edit.old.start..edit.old.end,
2825            edit.new.start..edit.new.end
2826        );
2827
2828        // Record which hunks were previously expanded.
2829        while let Some(item) = old_diff_transforms.item() {
2830            if let Some(hunk_info) = item.hunk_info() {
2831                log::trace!(
2832                    "previously expanded hunk at {:?}",
2833                    old_diff_transforms.start()
2834                );
2835                old_expanded_hunks.insert(hunk_info);
2836            }
2837            if old_diff_transforms.end().0 > edit.old.end {
2838                break;
2839            }
2840            old_diff_transforms.next();
2841        }
2842
2843        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2844        // For inverted diffs, hunks are always shown, so we can't skip this.
2845        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2846        if old_expanded_hunks.is_empty()
2847            && change_kind == DiffChangeKind::BufferEdited
2848            && !all_diff_hunks_expanded
2849            && !snapshot.has_inverted_diff
2850        {
2851            return false;
2852        }
2853
2854        // Visit each excerpt that intersects the edit.
2855        let mut did_expand_hunks = false;
2856        while let Some(excerpt) = excerpts.item() {
2857            // Recompute the expanded hunks in the portion of the excerpt that
2858            // intersects the edit.
2859            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2860                let buffer = &excerpt.buffer;
2861                let excerpt_start = *excerpts.start();
2862                let excerpt_end = excerpt_start + excerpt.text_summary.len;
2863                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
2864                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2865                let edit_buffer_start =
2866                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
2867                let edit_buffer_end =
2868                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
2869                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2870
2871                if let Some(main_buffer) = &diff.main_buffer {
2872                    for hunk in diff.hunks_intersecting_base_text_range(
2873                        edit_buffer_start..edit_buffer_end,
2874                        main_buffer,
2875                    ) {
2876                        did_expand_hunks = true;
2877                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
2878                        if hunk_buffer_range.start < excerpt_buffer_start {
2879                            log::trace!("skipping hunk that starts before excerpt");
2880                            continue;
2881                        }
2882                        hunk_buffer_range.end.to_point(&excerpt.buffer);
2883                        let hunk_excerpt_start = excerpt_start
2884                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2885                        let hunk_excerpt_end = excerpt_end
2886                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2887                        Self::push_buffer_content_transform(
2888                            snapshot,
2889                            new_diff_transforms,
2890                            hunk_excerpt_start,
2891                            *end_of_current_insert,
2892                        );
2893                        if !hunk_buffer_range.is_empty() {
2894                            let hunk_info = DiffTransformHunkInfo {
2895                                buffer_id: buffer.remote_id(),
2896                                hunk_start_anchor: hunk.buffer_range.start,
2897                                hunk_secondary_status: hunk.secondary_status,
2898                                is_logically_deleted: true,
2899                            };
2900                            *end_of_current_insert =
2901                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2902                        }
2903                    }
2904                } else {
2905                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
2906                        ..buffer.anchor_after(edit_buffer_end);
2907                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
2908                        if hunk.is_created_file() && !all_diff_hunks_expanded {
2909                            continue;
2910                        }
2911
2912                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
2913                        if hunk_buffer_range.start < excerpt_buffer_start {
2914                            log::trace!("skipping hunk that starts before excerpt");
2915                            continue;
2916                        }
2917
2918                        let hunk_info = DiffTransformHunkInfo {
2919                            buffer_id: buffer.remote_id(),
2920                            hunk_start_anchor: hunk.buffer_range.start,
2921                            hunk_secondary_status: hunk.secondary_status,
2922                            is_logically_deleted: false,
2923                        };
2924
2925                        let hunk_excerpt_start = excerpt_start
2926                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2927                        let hunk_excerpt_end = excerpt_end
2928                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2929
2930                        Self::push_buffer_content_transform(
2931                            snapshot,
2932                            new_diff_transforms,
2933                            hunk_excerpt_start,
2934                            *end_of_current_insert,
2935                        );
2936
2937                        // For every existing hunk, determine if it was previously expanded
2938                        // and if it should currently be expanded.
2939                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2940                        let should_expand_hunk = match &change_kind {
2941                            DiffChangeKind::DiffUpdated { base_changed: true } => {
2942                                was_previously_expanded || all_diff_hunks_expanded
2943                            }
2944                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2945                                let intersects = hunk_buffer_range.is_empty()
2946                                    || hunk_buffer_range.end > edit_buffer_start;
2947                                if *expand {
2948                                    intersects || was_previously_expanded || all_diff_hunks_expanded
2949                                } else {
2950                                    !intersects
2951                                        && (was_previously_expanded || all_diff_hunks_expanded)
2952                                }
2953                            }
2954                            _ => was_previously_expanded || all_diff_hunks_expanded,
2955                        };
2956
2957                        if should_expand_hunk {
2958                            did_expand_hunks = true;
2959                            log::trace!(
2960                                "expanding hunk {:?}, excerpt:{:?}",
2961                                hunk_excerpt_start..hunk_excerpt_end,
2962                                excerpt.id
2963                            );
2964
2965                            if !hunk.diff_base_byte_range.is_empty()
2966                                && hunk_buffer_range.start >= edit_buffer_start
2967                                && hunk_buffer_range.start <= excerpt_buffer_end
2968                                && snapshot.show_deleted_hunks
2969                            {
2970                                let base_text = diff.base_text();
2971                                let mut text_cursor =
2972                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2973                                let mut base_text_summary = text_cursor
2974                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
2975
2976                                let mut has_trailing_newline = false;
2977                                if base_text_summary.last_line_chars > 0 {
2978                                    base_text_summary += TextSummary::newline();
2979                                    has_trailing_newline = true;
2980                                }
2981
2982                                new_diff_transforms.push(
2983                                    DiffTransform::DeletedHunk {
2984                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
2985                                        summary: base_text_summary,
2986                                        buffer_id: excerpt.buffer.remote_id(),
2987                                        hunk_info,
2988                                        has_trailing_newline,
2989                                    },
2990                                    (),
2991                                );
2992                            }
2993
2994                            if !hunk_buffer_range.is_empty() {
2995                                *end_of_current_insert =
2996                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2997                            }
2998                        }
2999                    }
3000                }
3001            }
3002
3003            if excerpts.end() <= edit.new.end {
3004                excerpts.next();
3005            } else {
3006                break;
3007            }
3008        }
3009
3010        did_expand_hunks || !old_expanded_hunks.is_empty()
3011    }
3012
3013    fn append_diff_transforms(
3014        new_transforms: &mut SumTree<DiffTransform>,
3015        subtree: SumTree<DiffTransform>,
3016    ) {
3017        if let Some(DiffTransform::BufferContent {
3018            inserted_hunk_info,
3019            summary,
3020        }) = subtree.first()
3021            && Self::extend_last_buffer_content_transform(
3022                new_transforms,
3023                *inserted_hunk_info,
3024                *summary,
3025            )
3026        {
3027            let mut cursor = subtree.cursor::<()>(());
3028            cursor.next();
3029            cursor.next();
3030            new_transforms.append(cursor.suffix(), ());
3031            return;
3032        }
3033        new_transforms.append(subtree, ());
3034    }
3035
3036    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3037        if let DiffTransform::BufferContent {
3038            inserted_hunk_info: inserted_hunk_anchor,
3039            summary,
3040        } = transform
3041            && Self::extend_last_buffer_content_transform(
3042                new_transforms,
3043                inserted_hunk_anchor,
3044                summary,
3045            )
3046        {
3047            return;
3048        }
3049        new_transforms.push(transform, ());
3050    }
3051
3052    fn push_buffer_content_transform(
3053        old_snapshot: &MultiBufferSnapshot,
3054        new_transforms: &mut SumTree<DiffTransform>,
3055        end_offset: ExcerptOffset,
3056        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3057    ) {
3058        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3059            (end_offset.min(insertion_end_offset), Some(hunk_info))
3060        });
3061        let unchanged_region = [(end_offset, None)];
3062
3063        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3064        {
3065            let start_offset = new_transforms.summary().excerpt_len();
3066            if end_offset <= start_offset {
3067                continue;
3068            }
3069            let summary_to_add = old_snapshot
3070                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3071
3072            if !Self::extend_last_buffer_content_transform(
3073                new_transforms,
3074                inserted_hunk_info,
3075                summary_to_add,
3076            ) {
3077                new_transforms.push(
3078                    DiffTransform::BufferContent {
3079                        summary: summary_to_add,
3080                        inserted_hunk_info,
3081                    },
3082                    (),
3083                )
3084            }
3085        }
3086    }
3087
3088    fn extend_last_buffer_content_transform(
3089        new_transforms: &mut SumTree<DiffTransform>,
3090        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3091        summary_to_add: MBTextSummary,
3092    ) -> bool {
3093        let mut did_extend = false;
3094        new_transforms.update_last(
3095            |last_transform| {
3096                if let DiffTransform::BufferContent {
3097                    summary,
3098                    inserted_hunk_info: inserted_hunk_anchor,
3099                } = last_transform
3100                    && *inserted_hunk_anchor == new_inserted_hunk_info
3101                {
3102                    *summary += summary_to_add;
3103                    did_extend = true;
3104                }
3105            },
3106            (),
3107        );
3108        did_extend
3109    }
3110
3111    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3112        let snapshot = self.snapshot(cx);
3113        let excerpt_end = snapshot
3114            .excerpt_at(range.end)
3115            .map(|excerpt| excerpt.end_anchor().into())
3116            .unwrap_or(Anchor::Max);
3117        let point_range = range.to_point(&snapshot);
3118        let expand = !self.single_hunk_is_expanded(range, cx);
3119        let edits =
3120            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_end)], expand, cx);
3121        if !edits.is_empty() {
3122            self.subscriptions.publish(edits);
3123        }
3124        cx.emit(Event::DiffHunksToggled);
3125        cx.emit(Event::Edited {
3126            edited_buffer: None,
3127        });
3128    }
3129}
3130
3131fn build_excerpt_ranges(
3132    ranges: impl IntoIterator<Item = Range<Point>>,
3133    context_line_count: u32,
3134    buffer_snapshot: &BufferSnapshot,
3135) -> Vec<ExcerptRange<Point>> {
3136    ranges
3137        .into_iter()
3138        .map(|range| {
3139            let start_row = range.start.row.saturating_sub(context_line_count);
3140            let start = Point::new(start_row, 0);
3141            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3142            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3143            ExcerptRange {
3144                context: start..end,
3145                primary: range,
3146            }
3147        })
3148        .collect()
3149}
3150
3151#[cfg(any(test, feature = "test-support"))]
3152impl MultiBuffer {
3153    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3154        let buffer = cx.new(|cx| Buffer::local(text, cx));
3155        cx.new(|cx| Self::singleton(buffer, cx))
3156    }
3157
3158    pub fn build_multi<const COUNT: usize>(
3159        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3160        cx: &mut gpui::App,
3161    ) -> Entity<Self> {
3162        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3163        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3164            let buffer = cx.new(|cx| Buffer::local(text, cx));
3165            let snapshot = buffer.read(cx).snapshot();
3166            let excerpt_ranges = ranges
3167                .into_iter()
3168                .map(ExcerptRange::new)
3169                .collect::<Vec<_>>();
3170            multi.update(cx, |multi, cx| {
3171                multi.set_excerpt_ranges_for_path(
3172                    PathKey::sorted(ix as u64),
3173                    buffer,
3174                    &snapshot,
3175                    excerpt_ranges,
3176                    cx,
3177                )
3178            });
3179        }
3180
3181        multi
3182    }
3183
3184    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3185        cx.new(|cx| Self::singleton(buffer, cx))
3186    }
3187
3188    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3189        cx.new(|cx| {
3190            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3191            let mutation_count = rng.random_range(1..=5);
3192            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3193            multibuffer
3194        })
3195    }
3196
3197    pub fn randomly_edit(
3198        &mut self,
3199        rng: &mut impl rand::Rng,
3200        edit_count: usize,
3201        cx: &mut Context<Self>,
3202    ) {
3203        use util::RandomCharIter;
3204
3205        let snapshot = self.read(cx);
3206        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3207        let mut last_end = None;
3208        for _ in 0..edit_count {
3209            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3210                break;
3211            }
3212
3213            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3214            let end =
3215                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3216            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3217            last_end = Some(end);
3218
3219            let mut range = start..end;
3220            if rng.random_bool(0.2) {
3221                mem::swap(&mut range.start, &mut range.end);
3222            }
3223
3224            let new_text_len = rng.random_range(0..10);
3225            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3226
3227            edits.push((range, new_text.into()));
3228        }
3229        log::info!("mutating multi-buffer with {:?}", edits);
3230        drop(snapshot);
3231
3232        self.edit(edits, None, cx);
3233    }
3234
3235    pub fn randomly_edit_excerpts(
3236        &mut self,
3237        rng: &mut impl rand::Rng,
3238        mutation_count: usize,
3239        cx: &mut Context<Self>,
3240    ) {
3241        use rand::prelude::*;
3242        use std::env;
3243        use util::RandomCharIter;
3244
3245        let max_excerpts = env::var("MAX_EXCERPTS")
3246            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3247            .unwrap_or(5);
3248
3249        let mut buffers = Vec::new();
3250        for _ in 0..mutation_count {
3251            if rng.random_bool(0.05) {
3252                log::info!("Clearing multi-buffer");
3253                self.clear(cx);
3254                continue;
3255            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3256                let ids = self.excerpt_ids();
3257                let mut excerpts = HashSet::default();
3258                for _ in 0..rng.random_range(0..ids.len()) {
3259                    excerpts.extend(ids.choose(rng).copied());
3260                }
3261
3262                let line_count = rng.random_range(0..5);
3263
3264                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3265
3266                self.expand_excerpts(
3267                    excerpts.iter().cloned(),
3268                    line_count,
3269                    ExpandExcerptDirection::UpAndDown,
3270                    cx,
3271                );
3272                continue;
3273            }
3274
3275            let excerpt_ids = self.excerpt_ids();
3276            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3277                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3278                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3279                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3280                    let buffer = buffers.last().unwrap().read(cx);
3281                    log::info!(
3282                        "Creating new buffer {} with text: {:?}",
3283                        buffer.remote_id(),
3284                        buffer.text()
3285                    );
3286                    buffers.last().unwrap().clone()
3287                } else {
3288                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3289                };
3290
3291                let buffer = buffer_handle.read(cx);
3292                let buffer_text = buffer.text();
3293                let ranges = (0..rng.random_range(0..5))
3294                    .map(|_| {
3295                        let end_ix =
3296                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3297                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3298                        ExcerptRange::new(start_ix..end_ix)
3299                    })
3300                    .collect::<Vec<_>>();
3301                log::info!(
3302                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3303                    buffer_handle.read(cx).remote_id(),
3304                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3305                    ranges
3306                        .iter()
3307                        .map(|r| &buffer_text[r.context.clone()])
3308                        .collect::<Vec<_>>()
3309                );
3310
3311                let excerpt_id =
3312                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3313                log::info!("Inserted with ids: {:?}", excerpt_id);
3314            } else {
3315                let remove_count = rng.random_range(1..=excerpt_ids.len());
3316                let mut excerpts_to_remove = excerpt_ids
3317                    .choose_multiple(rng, remove_count)
3318                    .cloned()
3319                    .collect::<Vec<_>>();
3320                let snapshot = self.snapshot.borrow();
3321                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3322                drop(snapshot);
3323                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3324                self.remove_excerpts(excerpts_to_remove, cx);
3325            }
3326        }
3327    }
3328
3329    pub fn randomly_mutate(
3330        &mut self,
3331        rng: &mut impl rand::Rng,
3332        mutation_count: usize,
3333        cx: &mut Context<Self>,
3334    ) {
3335        use rand::prelude::*;
3336
3337        if rng.random_bool(0.7) || self.singleton {
3338            let buffer = self
3339                .buffers
3340                .values()
3341                .choose(rng)
3342                .map(|state| state.buffer.clone());
3343
3344            if let Some(buffer) = buffer {
3345                buffer.update(cx, |buffer, cx| {
3346                    if rng.random() {
3347                        buffer.randomly_edit(rng, mutation_count, cx);
3348                    } else {
3349                        buffer.randomly_undo_redo(rng, cx);
3350                    }
3351                });
3352            } else {
3353                self.randomly_edit(rng, mutation_count, cx);
3354            }
3355        } else {
3356            self.randomly_edit_excerpts(rng, mutation_count, cx);
3357        }
3358
3359        self.check_invariants(cx);
3360    }
3361
3362    fn check_invariants(&self, cx: &App) {
3363        self.read(cx).check_invariants();
3364    }
3365}
3366
3367impl EventEmitter<Event> for MultiBuffer {}
3368
3369impl MultiBufferSnapshot {
3370    pub fn text(&self) -> String {
3371        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3372            .map(|chunk| chunk.text)
3373            .collect()
3374    }
3375
3376    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3377        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3378            .flat_map(|c| c.chars().rev())
3379    }
3380
3381    fn reversed_chunks_in_range(
3382        &self,
3383        range: Range<MultiBufferOffset>,
3384    ) -> ReversedMultiBufferChunks<'_> {
3385        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3386        cursor.seek(&range.end);
3387        let current_chunks = cursor.region().as_ref().map(|region| {
3388            let start_overshoot = range.start.saturating_sub(region.range.start);
3389            let end_overshoot = range.end - region.range.start;
3390            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3391            let start = region.buffer_range.start + start_overshoot;
3392            region.buffer.reversed_chunks_in_range(start..end)
3393        });
3394        ReversedMultiBufferChunks {
3395            cursor,
3396            current_chunks,
3397            start: range.start,
3398            offset: range.end,
3399        }
3400    }
3401
3402    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3403        let offset = position.to_offset(self);
3404        self.text_for_range(offset..self.len())
3405            .flat_map(|chunk| chunk.chars())
3406    }
3407
3408    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3409        self.chunks(range, false).map(|chunk| chunk.text)
3410    }
3411
3412    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3413        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3414            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3415    }
3416
3417    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3418    where
3419        T: ToOffset,
3420    {
3421        let position = position.to_offset(self);
3422        position == self.clip_offset(position, Bias::Left)
3423            && self
3424                .bytes_in_range(position..self.len())
3425                .flatten()
3426                .copied()
3427                .take(needle.len())
3428                .eq(needle.bytes())
3429    }
3430
3431    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3432        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3433    }
3434
3435    pub fn diff_hunks_in_range<T: ToPoint>(
3436        &self,
3437        range: Range<T>,
3438    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3439        let query_range = range.start.to_point(self)..range.end.to_point(self);
3440        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3441            let diff = self.diffs.get(&buffer.remote_id())?;
3442            let iter = if let Some(main_buffer) = &diff.main_buffer {
3443                let buffer_start = buffer.point_to_offset(buffer_range.start);
3444                let buffer_end = buffer.point_to_offset(buffer_range.end);
3445                itertools::Either::Left(
3446                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3447                        .map(move |hunk| (hunk, buffer, true)),
3448                )
3449            } else {
3450                let buffer_start = buffer.anchor_before(buffer_range.start);
3451                let buffer_end = buffer.anchor_after(buffer_range.end);
3452                itertools::Either::Right(
3453                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3454                        .map(move |hunk| (hunk, buffer, false)),
3455                )
3456            };
3457            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3458                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3459                    return None;
3460                }
3461                let range = if is_inverted {
3462                    hunk.diff_base_byte_range.to_point(&buffer)
3463                } else {
3464                    hunk.range.clone()
3465                };
3466                Some((range, (hunk, is_inverted)))
3467            }))
3468        })
3469        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3470            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3471            {
3472                return None;
3473            }
3474            let end_row = if range.end.column == 0 {
3475                range.end.row
3476            } else {
3477                range.end.row + 1
3478            };
3479
3480            let word_diffs =
3481                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3482                    .then(|| {
3483                        let mut word_diffs = Vec::new();
3484
3485                        if self.show_deleted_hunks || is_inverted {
3486                            let hunk_start_offset = if is_inverted {
3487                                Anchor::in_buffer(
3488                                    excerpt.path_key_index,
3489                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3490                                )
3491                                .to_offset(self)
3492                            } else {
3493                                Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3494                                    .to_offset(self)
3495                            };
3496
3497                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3498                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3499                            }));
3500                        }
3501
3502                        if !is_inverted {
3503                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3504                                Anchor::range_in_buffer(excerpt.path_key_index, diff)
3505                                    .to_offset(self)
3506                            }));
3507                        }
3508                        word_diffs
3509                    })
3510                    .unwrap_or_default();
3511
3512            let buffer_range = if is_inverted {
3513                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3514                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3515            } else {
3516                hunk.buffer_range.clone()
3517            };
3518            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3519                DiffHunkStatusKind::Deleted
3520            } else if hunk.diff_base_byte_range.is_empty() {
3521                DiffHunkStatusKind::Added
3522            } else {
3523                DiffHunkStatusKind::Modified
3524            };
3525            Some(MultiBufferDiffHunk {
3526                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3527                buffer_id: excerpt.buffer.remote_id(),
3528                buffer_range,
3529                word_diffs,
3530                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3531                    ..BufferOffset(hunk.diff_base_byte_range.end),
3532                status: DiffHunkStatus {
3533                    kind: status_kind,
3534                    secondary: hunk.secondary_status,
3535                },
3536            })
3537        })
3538    }
3539
3540    fn excerpts_for_range<T: ToOffset>(
3541        &self,
3542        range: Range<T>,
3543    ) -> impl Iterator<Item = &Excerpt> + '_ {
3544        let range = range.start.to_offset(self)..range.end.to_offset(self);
3545        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3546        cursor.seek(&range.start);
3547        std::iter::from_fn(move || {
3548            let region = cursor.region()?;
3549            if region.range.start > range.end
3550                || region.range.start == range.end && region.range.start > range.start
3551            {
3552                return None;
3553            }
3554            let excerpt = region.excerpt;
3555            cursor.next_excerpt_forwards();
3556            Some(excerpt)
3557        })
3558    }
3559
3560    // todo!() repeats ids? seems weird
3561    pub fn buffer_ids_for_range<T: ToOffset>(
3562        &self,
3563        range: Range<T>,
3564    ) -> impl Iterator<Item = BufferId> + '_ {
3565        self.excerpts_for_range(range)
3566            .map(|excerpt| excerpt.buffer.remote_id())
3567    }
3568
3569    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3570    ///
3571    /// The passed in anchors must be ordered.
3572    pub fn text_anchors_to_visible_anchors(
3573        &self,
3574        anchors: impl IntoIterator<Item = text::Anchor>,
3575    ) -> Vec<Option<Anchor>> {
3576        let anchors = anchors.into_iter();
3577        let mut result = Vec::with_capacity(anchors.size_hint().0);
3578        let mut anchors = anchors.peekable();
3579        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3580        'anchors: while let Some(anchor) = anchors.peek() {
3581            let Some(buffer_id) = anchor.buffer_id else {
3582                anchors.next();
3583                result.push(None);
3584                continue 'anchors;
3585            };
3586            let mut same_buffer_anchors =
3587                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3588
3589            if let Some(path) = self.path_keys_by_buffer.get(&buffer_id) {
3590                let Some(mut next) = same_buffer_anchors.next() else {
3591                    continue 'anchors;
3592                };
3593                cursor.seek_forward(path, Bias::Left);
3594                'excerpts: loop {
3595                    let Some(excerpt) = cursor.item() else {
3596                        break;
3597                    };
3598                    if &excerpt.path_key != path {
3599                        break;
3600                    }
3601
3602                    loop {
3603                        // anchor is before the first excerpt
3604                        if excerpt
3605                            .range
3606                            .context
3607                            .start
3608                            .cmp(&next, &excerpt.buffer)
3609                            .is_gt()
3610                        {
3611                            // so we skip it and try the next anchor
3612                            result.push(None);
3613                            match same_buffer_anchors.next() {
3614                                Some(anchor) => next = anchor,
3615                                None => continue 'anchors,
3616                            }
3617                        // anchor is within the excerpt
3618                        } else if excerpt
3619                            .range
3620                            .context
3621                            .end
3622                            .cmp(&next, &excerpt.buffer)
3623                            .is_ge()
3624                        {
3625                            // record it and all following anchors that are within
3626                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3627                            result.extend(
3628                                same_buffer_anchors
3629                                    .peeking_take_while(|a| {
3630                                        excerpt.range.context.end.cmp(a, &excerpt.buffer).is_ge()
3631                                    })
3632                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3633                            );
3634                            match same_buffer_anchors.next() {
3635                                Some(anchor) => next = anchor,
3636                                None => continue 'anchors,
3637                            }
3638                        // anchor is after the excerpt, try the next one
3639                        } else {
3640                            cursor.next();
3641                            continue 'excerpts;
3642                        }
3643                    }
3644                }
3645                // account for `next`
3646                result.push(None);
3647            }
3648            result.extend(same_buffer_anchors.map(|_| None));
3649        }
3650
3651        result
3652    }
3653
3654    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3655        &self,
3656        ranges: impl Iterator<Item = Range<T>>,
3657    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3658        ranges.flat_map(|range| {
3659            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3660                .into_iter()
3661        })
3662    }
3663
3664    pub fn range_to_buffer_ranges<R, T>(
3665        &self,
3666        range: R,
3667    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
3668    where
3669        R: RangeBounds<T>,
3670        T: ToOffset,
3671    {
3672        self.range_to_buffer_ranges_with_context(range)
3673            .into_iter()
3674            .map(|(buffer, range, id, _context)| (buffer, range, id))
3675            .collect()
3676    }
3677
3678    pub fn range_to_buffer_ranges_with_context<R, T>(
3679        &self,
3680        range: R,
3681    ) -> Vec<(
3682        &BufferSnapshot,
3683        Range<BufferOffset>,
3684        ExcerptId,
3685        Range<text::Anchor>,
3686    )>
3687    where
3688        R: RangeBounds<T>,
3689        T: ToOffset,
3690    {
3691        let start = match range.start_bound() {
3692            Bound::Included(start) => start.to_offset(self),
3693            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3694            Bound::Unbounded => MultiBufferOffset::ZERO,
3695        };
3696        let end_bound = match range.end_bound() {
3697            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3698            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3699            Bound::Unbounded => Bound::Unbounded,
3700        };
3701        let bounds = (Bound::Included(start), end_bound);
3702
3703        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3704        cursor.seek(&start);
3705
3706        let mut result: Vec<(
3707            &BufferSnapshot,
3708            Range<BufferOffset>,
3709            ExcerptId,
3710            Range<text::Anchor>,
3711        )> = Vec::new();
3712        while let Some(region) = cursor.region() {
3713            let dominated_by_end_bound = match end_bound {
3714                Bound::Included(end) => region.range.start > end,
3715                Bound::Excluded(end) => region.range.start >= end,
3716                Bound::Unbounded => false,
3717            };
3718            if dominated_by_end_bound {
3719                break;
3720            }
3721            if region.is_main_buffer {
3722                let start_overshoot = start.saturating_sub(region.range.start);
3723                let end_offset = match end_bound {
3724                    Bound::Included(end) | Bound::Excluded(end) => end,
3725                    Bound::Unbounded => region.range.end,
3726                };
3727                let end_overshoot = end_offset.saturating_sub(region.range.start);
3728                let start = region
3729                    .buffer_range
3730                    .end
3731                    .min(region.buffer_range.start + start_overshoot);
3732                let end = region
3733                    .buffer_range
3734                    .end
3735                    .min(region.buffer_range.start + end_overshoot);
3736                let context = region.excerpt.range.context.clone();
3737                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
3738                    *excerpt_id == region.excerpt.id && prev_range.end == start
3739                }) {
3740                    prev.1.end = end;
3741                } else {
3742                    result.push((region.buffer, start..end, region.excerpt.id, context));
3743                }
3744            }
3745            cursor.next();
3746        }
3747
3748        if let Some(excerpt) = cursor.excerpt() {
3749            let dominated_by_prev_excerpt =
3750                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
3751            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3752                let excerpt_position = self.len();
3753                if bounds.contains(&excerpt_position) {
3754                    let buffer_offset =
3755                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
3756                    let context = excerpt.range.context.clone();
3757                    result.push((
3758                        &excerpt.buffer,
3759                        buffer_offset..buffer_offset,
3760                        excerpt.id,
3761                        context,
3762                    ));
3763                }
3764            }
3765        }
3766
3767        result
3768    }
3769
3770    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3771        &self,
3772        range: Range<T>,
3773    ) -> impl Iterator<
3774        Item = (
3775            &BufferSnapshot,
3776            Range<BufferOffset>,
3777            ExcerptId,
3778            Option<Anchor>,
3779        ),
3780    > + '_ {
3781        let start = range.start.to_offset(self);
3782        let end = range.end.to_offset(self);
3783
3784        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3785        cursor.seek(&start);
3786
3787        std::iter::from_fn(move || {
3788            let region = cursor.region()?;
3789            if region.range.start > end {
3790                return None;
3791            }
3792            let start_overshoot = start.saturating_sub(region.range.start);
3793            let end_overshoot = end.saturating_sub(region.range.start);
3794            let start = region
3795                .buffer_range
3796                .end
3797                .min(region.buffer_range.start + start_overshoot);
3798            let end = region
3799                .buffer_range
3800                .end
3801                .min(region.buffer_range.start + end_overshoot);
3802
3803            let region_excerpt_id = region.excerpt.id;
3804            let deleted_hunk_anchor = if region.is_main_buffer {
3805                None
3806            } else {
3807                Some(self.anchor_before(region.range.start))
3808            };
3809            let result = (
3810                region.buffer,
3811                start..end,
3812                region_excerpt_id,
3813                deleted_hunk_anchor,
3814            );
3815            cursor.next();
3816            Some(result)
3817        })
3818    }
3819
3820    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3821    /// coordinates.
3822    ///
3823    /// The given callback will be called for every excerpt intersecting the given range. It will
3824    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3825    /// The callback should return an iterator of metadata items from that buffer, each paired
3826    /// with a buffer range.
3827    ///
3828    /// The returned iterator yields each of these metadata items, paired with its range in
3829    /// multi-buffer coordinates.
3830    fn lift_buffer_metadata<'a, MBD, M, I>(
3831        &'a self,
3832        query_range: Range<MBD>,
3833        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3834    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3835    where
3836        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3837        MBD: MultiBufferDimension
3838            + Ord
3839            + Sub<Output = MBD::TextDimension>
3840            + ops::Add<MBD::TextDimension, Output = MBD>
3841            + ops::AddAssign<MBD::TextDimension>,
3842        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3843            + ops::Add<Output = MBD::TextDimension>
3844            + AddAssign<MBD::TextDimension>
3845            + Ord,
3846    {
3847        let mut current_excerpt_metadata: Option<(Excerpt, I)> = None;
3848        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3849
3850        // Find the excerpt and buffer offset where the given range ends.
3851        cursor.seek(&query_range.end);
3852        let mut range_end = None;
3853        while let Some(region) = cursor.region() {
3854            if region.is_main_buffer {
3855                let mut buffer_end = region.buffer_range.start;
3856                let overshoot = if query_range.end > region.range.start {
3857                    query_range.end - region.range.start
3858                } else {
3859                    <MBD::TextDimension>::default()
3860                };
3861                buffer_end = buffer_end + overshoot;
3862                range_end = Some((region.excerpt, buffer_end));
3863                break;
3864            }
3865            cursor.next();
3866        }
3867
3868        cursor.seek(&query_range.start);
3869
3870        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3871            && region.range.start > MBD::default()
3872        {
3873            cursor.prev()
3874        } else if let Some(region) = cursor.region()
3875            && region.is_main_buffer
3876            && region.diff_hunk_status.is_some()
3877        {
3878            cursor.prev();
3879            if cursor.region().is_none_or(|region| region.is_main_buffer) {
3880                cursor.next();
3881            }
3882        }
3883
3884        iter::from_fn(move || {
3885            loop {
3886                let excerpt = cursor.excerpt()?;
3887
3888                // If we have already retrieved metadata for this excerpt, continue to use it.
3889                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3890                    .as_mut()
3891                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3892                {
3893                    Some(metadata)
3894                }
3895                // Otherwise, compute the intersection of the input range with the excerpt's range,
3896                // and retrieve the metadata for the resulting range.
3897                else {
3898                    let region = cursor.region()?;
3899                    let mut buffer_start;
3900                    if region.is_main_buffer {
3901                        buffer_start = region.buffer_range.start;
3902                        if query_range.start > region.range.start {
3903                            let overshoot = query_range.start - region.range.start;
3904                            buffer_start = buffer_start + overshoot;
3905                        }
3906                        buffer_start = buffer_start.min(region.buffer_range.end);
3907                    } else {
3908                        buffer_start = cursor.main_buffer_position()?;
3909                    };
3910                    let mut buffer_end = excerpt
3911                        .range
3912                        .context
3913                        .end
3914                        .summary::<MBD::TextDimension>(&excerpt.buffer);
3915                    if let Some((end_excerpt, end_buffer_offset)) = range_end
3916                        && excerpt == end_excerpt
3917                    {
3918                        buffer_end = buffer_end.min(end_buffer_offset);
3919                    }
3920
3921                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3922                        .map(|iterator| &mut current_excerpt_metadata.insert((excerpt, iterator)).1)
3923                };
3924
3925                // Visit each metadata item.
3926                if let Some((metadata_buffer_range, metadata)) =
3927                    metadata_iter.and_then(Iterator::next)
3928                {
3929                    // Find the multibuffer regions that contain the start and end of
3930                    // the metadata item's range.
3931                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3932                        while let Some(region) = cursor.region() {
3933                            if (region.is_main_buffer
3934                                && (region.buffer_range.end >= metadata_buffer_range.start
3935                                    || cursor.is_at_end_of_excerpt()))
3936                                || (!region.is_main_buffer
3937                                    && region.buffer_range.start == metadata_buffer_range.start)
3938                            {
3939                                break;
3940                            }
3941                            cursor.next();
3942                        }
3943                    }
3944                    let start_region = cursor.region()?.clone();
3945                    while let Some(region) = cursor.region() {
3946                        if region.is_main_buffer
3947                            && (region.buffer_range.end > metadata_buffer_range.end
3948                                || cursor.is_at_end_of_excerpt())
3949                        {
3950                            break;
3951                        }
3952                        cursor.next();
3953                    }
3954                    let end_region = cursor.region();
3955
3956                    // Convert the metadata item's range into multibuffer coordinates.
3957                    let mut start_position = start_region.range.start;
3958                    let region_buffer_start = start_region.buffer_range.start;
3959                    if start_region.is_main_buffer
3960                        && metadata_buffer_range.start > region_buffer_start
3961                    {
3962                        start_position =
3963                            start_position + (metadata_buffer_range.start - region_buffer_start);
3964                        start_position = start_position.min(start_region.range.end);
3965                    }
3966
3967                    let mut end_position = self.max_position();
3968                    if let Some(end_region) = &end_region {
3969                        end_position = end_region.range.start;
3970                        debug_assert!(end_region.is_main_buffer);
3971                        let region_buffer_start = end_region.buffer_range.start;
3972                        if metadata_buffer_range.end > region_buffer_start {
3973                            end_position =
3974                                end_position + (metadata_buffer_range.end - region_buffer_start);
3975                        }
3976                        end_position = end_position.min(end_region.range.end);
3977                    }
3978
3979                    if start_position <= query_range.end && end_position >= query_range.start {
3980                        return Some((start_position..end_position, metadata, excerpt));
3981                    }
3982                }
3983                // When there are no more metadata items for this excerpt, move to the next excerpt.
3984                else {
3985                    current_excerpt_metadata.take();
3986                    if let Some((end_excerpt, _)) = range_end
3987                        && excerpt == end_excerpt
3988                    {
3989                        return None;
3990                    }
3991                    cursor.next_excerpt_forwards();
3992                }
3993            }
3994        })
3995    }
3996
3997    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3998        let offset = position.to_offset(self);
3999
4000        let mut cursor = self
4001            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4002            );
4003        cursor.seek(&DimensionPair {
4004            key: offset,
4005            value: None,
4006        });
4007        cursor.seek_to_start_of_current_excerpt();
4008        let excerpt = cursor.excerpt()?;
4009
4010        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4011        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4012        let current_position = match self.anchor_before(offset) {
4013            Anchor::Min => 0,
4014            Anchor::Excerpt(excerpt_anchor) => {
4015                excerpt_anchor.text_anchor().to_offset(&excerpt.buffer)
4016            }
4017            Anchor::Max => unreachable!(),
4018        };
4019
4020        if let Some(diff) = self.diffs.get(&excerpt.buffer.remote_id()) {
4021            if let Some(main_buffer) = &diff.main_buffer {
4022                for hunk in diff
4023                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4024                {
4025                    if hunk.diff_base_byte_range.end >= current_position {
4026                        continue;
4027                    }
4028                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4029                    let start =
4030                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4031                    return Some(MultiBufferRow(start.row));
4032                }
4033            } else {
4034                let excerpt_end = excerpt
4035                    .buffer
4036                    .anchor_before(excerpt_end.min(current_position));
4037                for hunk in diff.hunks_intersecting_range_rev(
4038                    excerpt.range.context.start..excerpt_end,
4039                    &excerpt.buffer,
4040                ) {
4041                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4042                    if hunk_end >= current_position {
4043                        continue;
4044                    }
4045                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4046                        .to_point(self);
4047                    return Some(MultiBufferRow(start.row));
4048                }
4049            }
4050        }
4051
4052        loop {
4053            cursor.prev_excerpt();
4054            let excerpt = cursor.excerpt()?;
4055
4056            let Some(diff) = self.diffs.get(&excerpt.buffer.remote_id()) else {
4057                continue;
4058            };
4059            if let Some(main_buffer) = &diff.main_buffer {
4060                let Some(hunk) = diff
4061                    .hunks_intersecting_base_text_range_rev(
4062                        excerpt.range.context.to_offset(&excerpt.buffer),
4063                        main_buffer,
4064                    )
4065                    .next()
4066                else {
4067                    continue;
4068                };
4069                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4070                let start = Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4071                return Some(MultiBufferRow(start.row));
4072            } else {
4073                let Some(hunk) = diff
4074                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4075                    .next()
4076                else {
4077                    continue;
4078                };
4079                let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4080                    .to_point(self);
4081                return Some(MultiBufferRow(start.row));
4082            }
4083        }
4084    }
4085
4086    pub fn has_diff_hunks(&self) -> bool {
4087        self.diffs.values().any(|diff| !diff.is_empty())
4088    }
4089
4090    pub fn is_inside_word<T: ToOffset>(
4091        &self,
4092        position: T,
4093        scope_context: Option<CharScopeContext>,
4094    ) -> bool {
4095        let position = position.to_offset(self);
4096        let classifier = self
4097            .char_classifier_at(position)
4098            .scope_context(scope_context);
4099        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4100        let prev_char_kind = self
4101            .reversed_chars_at(position)
4102            .next()
4103            .map(|c| classifier.kind(c));
4104        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4105    }
4106
4107    pub fn surrounding_word<T: ToOffset>(
4108        &self,
4109        start: T,
4110        scope_context: Option<CharScopeContext>,
4111    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4112        let mut start = start.to_offset(self);
4113        let mut end = start;
4114        let mut next_chars = self.chars_at(start).peekable();
4115        let mut prev_chars = self.reversed_chars_at(start).peekable();
4116
4117        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4118
4119        let word_kind = cmp::max(
4120            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4121            next_chars.peek().copied().map(|c| classifier.kind(c)),
4122        );
4123
4124        for ch in prev_chars {
4125            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4126                start -= ch.len_utf8();
4127            } else {
4128                break;
4129            }
4130        }
4131
4132        for ch in next_chars {
4133            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4134                end += ch.len_utf8();
4135            } else {
4136                break;
4137            }
4138        }
4139
4140        (start..end, word_kind)
4141    }
4142
4143    pub fn char_kind_before<T: ToOffset>(
4144        &self,
4145        start: T,
4146        scope_context: Option<CharScopeContext>,
4147    ) -> Option<CharKind> {
4148        let start = start.to_offset(self);
4149        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4150        self.reversed_chars_at(start)
4151            .next()
4152            .map(|ch| classifier.kind(ch))
4153    }
4154
4155    pub fn is_singleton(&self) -> bool {
4156        self.singleton
4157    }
4158
4159    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4160        if self.singleton {
4161            self.excerpts
4162                .iter()
4163                .next()
4164                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4165        } else {
4166            None
4167        }
4168    }
4169
4170    pub fn len(&self) -> MultiBufferOffset {
4171        self.diff_transforms.summary().output.len
4172    }
4173
4174    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4175        MBD::from_summary(&self.text_summary())
4176    }
4177
4178    pub fn is_empty(&self) -> bool {
4179        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4180    }
4181
4182    pub fn widest_line_number(&self) -> u32 {
4183        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4184        self.excerpts.summary().widest_line_number + 1
4185    }
4186
4187    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4188        let range = range.start.to_offset(self)..range.end.to_offset(self);
4189        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4190        excerpts.seek(&range.start);
4191
4192        let mut chunk;
4193        let mut has_trailing_newline;
4194        let excerpt_bytes;
4195        if let Some(region) = excerpts.region() {
4196            let mut bytes = region.buffer.bytes_in_range(
4197                region.buffer_range.start + (range.start - region.range.start)
4198                    ..(region.buffer_range.start + (range.end - region.range.start))
4199                        .min(region.buffer_range.end),
4200            );
4201            chunk = bytes.next().unwrap_or(&[][..]);
4202            excerpt_bytes = Some(bytes);
4203            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4204            if chunk.is_empty() && has_trailing_newline {
4205                chunk = b"\n";
4206                has_trailing_newline = false;
4207            }
4208        } else {
4209            chunk = &[][..];
4210            excerpt_bytes = None;
4211            has_trailing_newline = false;
4212        };
4213
4214        MultiBufferBytes {
4215            range,
4216            cursor: excerpts,
4217            excerpt_bytes,
4218            has_trailing_newline,
4219            chunk,
4220        }
4221    }
4222
4223    pub fn reversed_bytes_in_range<T: ToOffset>(
4224        &self,
4225        range: Range<T>,
4226    ) -> ReversedMultiBufferBytes<'_> {
4227        let range = range.start.to_offset(self)..range.end.to_offset(self);
4228        let mut chunks = self.reversed_chunks_in_range(range.clone());
4229        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4230        ReversedMultiBufferBytes {
4231            range,
4232            chunks,
4233            chunk,
4234        }
4235    }
4236
4237    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4238        let mut cursor = self.cursor::<Point, Point>();
4239        cursor.seek(&Point::new(start_row.0, 0));
4240        let mut result = MultiBufferRows {
4241            point: Point::new(0, 0),
4242            is_empty: self.excerpts.is_empty(),
4243            is_singleton: self.is_singleton(),
4244            cursor,
4245        };
4246        result.seek(start_row);
4247        result
4248    }
4249
4250    pub fn chunks<T: ToOffset>(
4251        &self,
4252        range: Range<T>,
4253        language_aware: bool,
4254    ) -> MultiBufferChunks<'_> {
4255        let mut chunks = MultiBufferChunks {
4256            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4257                ..ExcerptDimension(MultiBufferOffset::ZERO),
4258            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4259            excerpts: self.excerpts.cursor(()),
4260            diff_transforms: self.diff_transforms.cursor(()),
4261            diffs: &self.diffs,
4262            diff_base_chunks: None,
4263            excerpt_chunks: None,
4264            buffer_chunk: None,
4265            language_aware,
4266        };
4267        let range = range.start.to_offset(self)..range.end.to_offset(self);
4268        chunks.seek(range);
4269        chunks
4270    }
4271
4272    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4273        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4274    }
4275
4276    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4277        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4278    }
4279
4280    pub fn clip_offset_utf16(
4281        &self,
4282        offset: MultiBufferOffsetUtf16,
4283        bias: Bias,
4284    ) -> MultiBufferOffsetUtf16 {
4285        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4286    }
4287
4288    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4289        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4290            buffer.clip_point_utf16(Unclipped(point), bias)
4291        })
4292    }
4293
4294    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4295        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4296    }
4297
4298    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4299        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4300    }
4301
4302    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4303        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4304    }
4305
4306    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4307        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4308    }
4309
4310    #[instrument(skip_all)]
4311    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4312        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4313    }
4314
4315    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4316        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4317    }
4318
4319    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4320        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4321    }
4322
4323    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4324        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4325    }
4326
4327    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4328        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4329    }
4330
4331    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4332        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4333    }
4334
4335    fn clip_dimension<MBD, BD>(
4336        &self,
4337        position: MBD,
4338        bias: Bias,
4339        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4340    ) -> MBD
4341    where
4342        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4343        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4344    {
4345        let mut cursor = self.cursor::<MBD, BD>();
4346        cursor.seek(&position);
4347        if let Some(region) = cursor.region() {
4348            if position >= region.range.end {
4349                return region.range.end;
4350            }
4351            let overshoot = position - region.range.start;
4352            let mut buffer_position = region.buffer_range.start;
4353            buffer_position += overshoot;
4354            let clipped_buffer_position =
4355                clip_buffer_position(region.buffer, buffer_position, bias);
4356            let mut position = region.range.start;
4357            position += clipped_buffer_position - region.buffer_range.start;
4358            position
4359        } else {
4360            self.max_position()
4361        }
4362    }
4363
4364    #[instrument(skip_all)]
4365    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4366        &self,
4367        key: MBR1,
4368        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4369    ) -> MBR2
4370    where
4371        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4372        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4373        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4374        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4375    {
4376        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4377        cursor.seek(&DimensionPair { key, value: None });
4378        if let Some(region) = cursor.region() {
4379            if key >= region.range.end.key {
4380                return region.range.end.value.unwrap();
4381            }
4382            let start_key = region.range.start.key;
4383            let start_value = region.range.start.value.unwrap();
4384            let buffer_start_key = region.buffer_range.start.key;
4385            let buffer_start_value = region.buffer_range.start.value.unwrap();
4386            let mut buffer_key = buffer_start_key;
4387            buffer_key += key - start_key;
4388            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4389            let mut result = start_value;
4390            result += buffer_value - buffer_start_value;
4391            result
4392        } else {
4393            self.max_position()
4394        }
4395    }
4396
4397    pub fn point_to_buffer_offset<T: ToOffset>(
4398        &self,
4399        point: T,
4400    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4401        let offset = point.to_offset(self);
4402        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4403        cursor.seek(&offset);
4404        let region = cursor.region()?;
4405        let overshoot = offset - region.range.start;
4406        let buffer_offset = region.buffer_range.start + overshoot;
4407        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4408            && region.has_trailing_newline
4409            && !region.is_main_buffer
4410        {
4411            let main_buffer_position = cursor.main_buffer_position()?;
4412            let buffer_snapshot = &cursor.excerpt()?.buffer;
4413            return Some((buffer_snapshot, main_buffer_position));
4414        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4415            return None;
4416        }
4417        Some((region.buffer, buffer_offset))
4418    }
4419
4420    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4421        let mut cursor = self.cursor::<Point, Point>();
4422        cursor.seek(&point);
4423        let region = cursor.region()?;
4424        let overshoot = point - region.range.start;
4425        let buffer_point = region.buffer_range.start + overshoot;
4426        let excerpt = cursor.excerpt()?;
4427        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4428            && region.has_trailing_newline
4429            && !region.is_main_buffer
4430        {
4431            return Some((&excerpt.buffer, cursor.main_buffer_position()?));
4432        } else if buffer_point > region.buffer.max_point() {
4433            return None;
4434        }
4435        Some((region.buffer, buffer_point))
4436    }
4437
4438    pub fn suggested_indents(
4439        &self,
4440        rows: impl IntoIterator<Item = u32>,
4441        cx: &App,
4442    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4443        let mut result = BTreeMap::new();
4444        self.suggested_indents_callback(
4445            rows,
4446            &mut |row, indent| {
4447                result.insert(row, indent);
4448                ControlFlow::Continue(())
4449            },
4450            cx,
4451        );
4452        result
4453    }
4454
4455    // move this to be a generator once those are a thing
4456    pub fn suggested_indents_callback(
4457        &self,
4458        rows: impl IntoIterator<Item = u32>,
4459        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4460        cx: &App,
4461    ) {
4462        let mut rows_for_excerpt = Vec::new();
4463        let mut cursor = self.cursor::<Point, Point>();
4464        let mut rows = rows.into_iter().peekable();
4465        let mut prev_row = u32::MAX;
4466        let mut prev_language_indent_size = IndentSize::default();
4467
4468        while let Some(row) = rows.next() {
4469            cursor.seek(&Point::new(row, 0));
4470            let Some(region) = cursor.region() else {
4471                continue;
4472            };
4473
4474            // Retrieve the language and indent size once for each disjoint region being indented.
4475            let single_indent_size = if row.saturating_sub(1) == prev_row {
4476                prev_language_indent_size
4477            } else {
4478                region
4479                    .buffer
4480                    .language_indent_size_at(Point::new(row, 0), cx)
4481            };
4482            prev_language_indent_size = single_indent_size;
4483            prev_row = row;
4484
4485            let start_buffer_row = region.buffer_range.start.row;
4486            let start_multibuffer_row = region.range.start.row;
4487            let end_multibuffer_row = region.range.end.row;
4488
4489            rows_for_excerpt.push(row);
4490            while let Some(next_row) = rows.peek().copied() {
4491                if end_multibuffer_row > next_row {
4492                    rows_for_excerpt.push(next_row);
4493                    rows.next();
4494                } else {
4495                    break;
4496                }
4497            }
4498
4499            let buffer_rows = rows_for_excerpt
4500                .drain(..)
4501                .map(|row| start_buffer_row + row - start_multibuffer_row);
4502            let buffer_indents = region
4503                .buffer
4504                .suggested_indents(buffer_rows, single_indent_size);
4505            for (row, indent) in buffer_indents {
4506                if cb(
4507                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4508                    indent,
4509                )
4510                .is_break()
4511                {
4512                    return;
4513                }
4514            }
4515        }
4516    }
4517
4518    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4519        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4520            let mut size = buffer.indent_size_for_line(range.start.row);
4521            size.len = size
4522                .len
4523                .min(range.end.column)
4524                .saturating_sub(range.start.column);
4525            size
4526        } else {
4527            IndentSize::spaces(0)
4528        }
4529    }
4530
4531    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4532        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4533            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4534        } else {
4535            LineIndent::spaces(0)
4536        }
4537    }
4538
4539    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4540        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4541
4542        if self.language_settings(cx).extend_comment_on_newline
4543            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4544        {
4545            let delimiters = language_scope.line_comment_prefixes();
4546            for delimiter in delimiters {
4547                if *self
4548                    .chars_at(Point::new(row.0, indent.len() as u32))
4549                    .take(delimiter.chars().count())
4550                    .collect::<String>()
4551                    .as_str()
4552                    == **delimiter
4553                {
4554                    indent.push_str(delimiter);
4555                    break;
4556                }
4557            }
4558        }
4559
4560        indent
4561    }
4562
4563    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4564    where
4565        T: ToOffset,
4566    {
4567        for char in self.reversed_chars_at(position) {
4568            if !char.is_whitespace() {
4569                return false;
4570            }
4571            if char == '\n' {
4572                return true;
4573            }
4574        }
4575        true
4576    }
4577
4578    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4579        while row.0 > 0 {
4580            row.0 -= 1;
4581            if !self.is_line_blank(row) {
4582                return Some(row);
4583            }
4584        }
4585        None
4586    }
4587
4588    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4589        if let Some((_, range)) = self.buffer_line_for_row(row) {
4590            range.end.column - range.start.column
4591        } else {
4592            0
4593        }
4594    }
4595
4596    pub fn buffer_line_for_row(
4597        &self,
4598        row: MultiBufferRow,
4599    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4600        let mut cursor = self.cursor::<Point, Point>();
4601        let point = Point::new(row.0, 0);
4602        cursor.seek(&point);
4603        let region = cursor.region()?;
4604        let overshoot = point.min(region.range.end) - region.range.start;
4605        let buffer_point = region.buffer_range.start + overshoot;
4606        if buffer_point.row > region.buffer_range.end.row {
4607            return None;
4608        }
4609        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4610        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4611            .min(region.buffer_range.end);
4612        Some((region.buffer, line_start..line_end))
4613    }
4614
4615    pub fn max_point(&self) -> Point {
4616        self.text_summary().lines
4617    }
4618
4619    pub fn max_row(&self) -> MultiBufferRow {
4620        MultiBufferRow(self.text_summary().lines.row)
4621    }
4622
4623    pub fn text_summary(&self) -> MBTextSummary {
4624        self.diff_transforms.summary().output
4625    }
4626
4627    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4628    where
4629        MBD: MultiBufferDimension + AddAssign,
4630        O: ToOffset,
4631    {
4632        let range = range.start.to_offset(self)..range.end.to_offset(self);
4633        let mut cursor = self
4634            .diff_transforms
4635            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4636        cursor.seek(&range.start, Bias::Right);
4637
4638        let Some(first_transform) = cursor.item() else {
4639            return MBD::from_summary(&MBTextSummary::default());
4640        };
4641
4642        let diff_transform_start = cursor.start().0;
4643        let diff_transform_end = cursor.end().0;
4644        let diff_start = range.start;
4645        let start_overshoot = diff_start - diff_transform_start;
4646        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4647
4648        let mut result = match first_transform {
4649            DiffTransform::BufferContent { .. } => {
4650                let excerpt_start = cursor.start().1 + start_overshoot;
4651                let excerpt_end = cursor.start().1 + end_overshoot;
4652                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4653            }
4654            DiffTransform::DeletedHunk {
4655                buffer_id,
4656                base_text_byte_range,
4657                has_trailing_newline,
4658                ..
4659            } => {
4660                let buffer_start = base_text_byte_range.start + start_overshoot;
4661                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4662                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4663                    panic!("{:?} is in non-existent deleted hunk", range.start)
4664                };
4665
4666                let include_trailing_newline =
4667                    *has_trailing_newline && range.end >= diff_transform_end;
4668                if include_trailing_newline {
4669                    buffer_end -= 1;
4670                }
4671
4672                let mut summary = base_text
4673                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4674
4675                if include_trailing_newline {
4676                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4677                        &TextSummary::newline(),
4678                    ))
4679                }
4680
4681                let mut result = MBD::default();
4682                result.add_text_dim(&summary);
4683                result
4684            }
4685        };
4686        if range.end < diff_transform_end {
4687            return result;
4688        }
4689
4690        cursor.next();
4691        result.add_mb_text_summary(
4692            &cursor
4693                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4694                .0,
4695        );
4696
4697        let Some(last_transform) = cursor.item() else {
4698            return result;
4699        };
4700
4701        let overshoot = range.end - cursor.start().0;
4702        let suffix = match last_transform {
4703            DiffTransform::BufferContent { .. } => {
4704                let end = cursor.start().1 + overshoot;
4705                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4706            }
4707            DiffTransform::DeletedHunk {
4708                base_text_byte_range,
4709                buffer_id,
4710                has_trailing_newline,
4711                ..
4712            } => {
4713                let buffer_end = base_text_byte_range.start + overshoot;
4714                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4715                    panic!("{:?} is in non-existent deleted hunk", range.end)
4716                };
4717
4718                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4719                    base_text_byte_range.start..buffer_end,
4720                );
4721                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4722                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4723                        &TextSummary::from("\n"),
4724                    ))
4725                }
4726
4727                let mut result = MBD::default();
4728                result.add_text_dim(&suffix);
4729                result
4730            }
4731        };
4732
4733        result += suffix;
4734        result
4735    }
4736
4737    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4738    where
4739        MBD: MultiBufferDimension + AddAssign,
4740    {
4741        let mut summary = MBD::default();
4742        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4743        cursor.seek(&range.start, Bias::Right);
4744        if let Some(excerpt) = cursor.item() {
4745            let mut end_before_newline = cursor.end();
4746            if excerpt.has_trailing_newline {
4747                end_before_newline -= 1;
4748            }
4749
4750            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4751            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4752            let end_in_excerpt =
4753                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4754            summary.add_text_dim(
4755                &excerpt
4756                    .buffer
4757                    .text_summary_for_range::<MBD::TextDimension, _>(
4758                        start_in_excerpt..end_in_excerpt,
4759                    ),
4760            );
4761
4762            if range.end > end_before_newline {
4763                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4764            }
4765
4766            cursor.next();
4767        }
4768
4769        if range.end > *cursor.start() {
4770            summary += cursor
4771                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4772                .0;
4773            if let Some(excerpt) = cursor.item() {
4774                range.end = cmp::max(*cursor.start(), range.end);
4775
4776                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4777                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4778                summary.add_text_dim(
4779                    &excerpt
4780                        .buffer
4781                        .text_summary_for_range::<MBD::TextDimension, _>(
4782                            excerpt_start..end_in_excerpt,
4783                        ),
4784                );
4785            }
4786        }
4787
4788        summary
4789    }
4790
4791    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4792    where
4793        MBD: MultiBufferDimension
4794            + Ord
4795            + Sub<Output = MBD::TextDimension>
4796            + Sub<MBD::TextDimension, Output = MBD>
4797            + AddAssign<MBD::TextDimension>
4798            + Add<MBD::TextDimension, Output = MBD>,
4799        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4800    {
4801        let target = anchor.seek_target(self);
4802        let anchor = match anchor {
4803            Anchor::Min => {
4804                return MBD::default();
4805            }
4806            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4807            Anchor::Max => {
4808                return MBD::from_summary(&self.text_summary());
4809            }
4810        };
4811
4812        let (start, _, item) = self
4813            .excerpts
4814            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4815        let start = MBD::from_summary(&start.text);
4816
4817        let excerpt_start_position = ExcerptDimension(start);
4818        if self.diff_transforms.is_empty() {
4819            if let Some(excerpt) = item {
4820                if !excerpt.contains(anchor) {
4821                    return excerpt_start_position.0;
4822                }
4823                let excerpt_buffer_start = excerpt
4824                    .range
4825                    .context
4826                    .start
4827                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4828                let excerpt_buffer_end = excerpt
4829                    .range
4830                    .context
4831                    .end
4832                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4833                let buffer_summary = anchor
4834                    .text_anchor()
4835                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4836                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4837                let mut position = excerpt_start_position;
4838                if summary > excerpt_buffer_start {
4839                    position += summary - excerpt_buffer_start;
4840                }
4841
4842                position.0
4843            } else {
4844                excerpt_start_position.0
4845            }
4846        } else {
4847            let mut diff_transforms_cursor = self
4848                .diff_transforms
4849                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4850            diff_transforms_cursor.next();
4851
4852            if let Some(excerpt) = item {
4853                if !excerpt.contains(anchor) {
4854                    return self.summary_for_excerpt_position_without_hunks(
4855                        Bias::Left,
4856                        excerpt_start_position,
4857                        &mut diff_transforms_cursor,
4858                    );
4859                }
4860                let excerpt_buffer_start = excerpt
4861                    .range
4862                    .context
4863                    .start
4864                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4865                let excerpt_buffer_end = excerpt
4866                    .range
4867                    .context
4868                    .end
4869                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4870                let buffer_summary = anchor
4871                    .text_anchor()
4872                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4873                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4874                let mut position = excerpt_start_position;
4875                if summary > excerpt_buffer_start {
4876                    position += summary - excerpt_buffer_start;
4877                }
4878
4879                if diff_transforms_cursor.start().0 < position {
4880                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
4881                }
4882                self.summary_for_anchor_with_excerpt_position(
4883                    *anchor,
4884                    position,
4885                    &mut diff_transforms_cursor,
4886                    &excerpt.buffer,
4887                )
4888            } else {
4889                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
4890                self.summary_for_excerpt_position_without_hunks(
4891                    Bias::Right,
4892                    excerpt_start_position,
4893                    &mut diff_transforms_cursor,
4894                )
4895            }
4896        }
4897    }
4898
4899    /// Maps an anchor's excerpt-space position to its output-space position by
4900    /// walking the diff transforms. The cursor is shared across consecutive
4901    /// calls, so it may already be partway through the transform list.
4902    fn summary_for_anchor_with_excerpt_position<MBD>(
4903        &self,
4904        anchor: ExcerptAnchor,
4905        excerpt_position: ExcerptDimension<MBD>,
4906        diff_transforms: &mut Cursor<
4907            DiffTransform,
4908            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4909        >,
4910        excerpt_buffer: &text::BufferSnapshot,
4911    ) -> MBD
4912    where
4913        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4914    {
4915        loop {
4916            let transform_end_position = diff_transforms.end().0;
4917            let item = diff_transforms.item();
4918            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4919
4920            // A right-biased anchor at a transform boundary belongs to the
4921            // *next* transform, so advance past the current one.
4922            if anchor.bias == Bias::Right && at_transform_end {
4923                diff_transforms.next();
4924                continue;
4925            }
4926
4927            let mut position = diff_transforms.start().1;
4928            match item {
4929                Some(DiffTransform::DeletedHunk {
4930                    buffer_id,
4931                    base_text_byte_range,
4932                    hunk_info,
4933                    ..
4934                }) => {
4935                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
4936                        && let Some(base_text) =
4937                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4938                        && diff_base_anchor.is_valid(&base_text)
4939                    {
4940                        // The anchor carries a diff-base position — resolve it
4941                        // to a location inside the deleted hunk.
4942                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4943                        if base_text_offset >= base_text_byte_range.start
4944                            && base_text_offset <= base_text_byte_range.end
4945                        {
4946                            let position_in_hunk = base_text
4947                                .text_summary_for_range::<MBD::TextDimension, _>(
4948                                    base_text_byte_range.start..base_text_offset,
4949                                );
4950                            position.0.add_text_dim(&position_in_hunk);
4951                        } else if at_transform_end {
4952                            // diff_base offset falls outside this hunk's range;
4953                            // advance to see if the next transform is a better fit.
4954                            diff_transforms.next();
4955                            continue;
4956                        }
4957                    } else if at_transform_end
4958                        && anchor
4959                            .text_anchor()
4960                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
4961                            .is_gt()
4962                    {
4963                        // The anchor has no (valid) diff-base position, so it
4964                        // belongs in the buffer content, not in the deleted
4965                        // hunk. However, after an edit deletes the text between
4966                        // the hunk boundary and this anchor, both resolve to
4967                        // the same excerpt_position—landing us here on the
4968                        // DeletedHunk left behind by the shared cursor. Use the
4969                        // CRDT ordering to detect that the anchor is strictly
4970                        // *past* the hunk boundary and skip to the following
4971                        // BufferContent.
4972                        diff_transforms.next();
4973                        continue;
4974                    }
4975                }
4976                _ => {
4977                    // On a BufferContent (or no transform). If the anchor
4978                    // carries a diff_base_anchor it needs a DeletedHunk, so
4979                    // advance to find one.
4980                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4981                        diff_transforms.next();
4982                        continue;
4983                    }
4984                    let overshoot = excerpt_position - diff_transforms.start().0;
4985                    position += overshoot;
4986                }
4987            }
4988
4989            return position.0;
4990        }
4991    }
4992
4993    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
4994    fn summary_for_excerpt_position_without_hunks<MBD>(
4995        &self,
4996        bias: Bias,
4997        excerpt_position: ExcerptDimension<MBD>,
4998        diff_transforms: &mut Cursor<
4999            DiffTransform,
5000            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5001        >,
5002    ) -> MBD
5003    where
5004        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5005    {
5006        loop {
5007            let transform_end_position = diff_transforms.end().0;
5008            let item = diff_transforms.item();
5009            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5010
5011            // A right-biased anchor at a transform boundary belongs to the
5012            // *next* transform, so advance past the current one.
5013            if bias == Bias::Right && at_transform_end {
5014                diff_transforms.next();
5015                continue;
5016            }
5017
5018            let mut position = diff_transforms.start().1;
5019            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5020                let overshoot = excerpt_position - diff_transforms.start().0;
5021                position += overshoot;
5022            }
5023
5024            return position.0;
5025        }
5026    }
5027
5028    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5029        let anchor = match anchor {
5030            Anchor::Min => return ExcerptOffset::default(),
5031            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5032            Anchor::Max => return self.excerpts.summary().len(),
5033        };
5034        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5035        let target = anchor.seek_target(self);
5036
5037        cursor.seek(&target, Bias::Left);
5038
5039        let mut position = cursor.start().len();
5040        if let Some(excerpt) = cursor.item()
5041            && excerpt.contains(anchor)
5042        {
5043            let excerpt_buffer_start = excerpt
5044                .buffer
5045                .offset_for_anchor(&excerpt.range.context.start);
5046            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5047            let buffer_position = cmp::min(
5048                excerpt_buffer_end,
5049                excerpt.buffer.offset_for_anchor(&anchor.text_anchor()),
5050            );
5051            if buffer_position > excerpt_buffer_start {
5052                position += buffer_position - excerpt_buffer_start;
5053            }
5054        }
5055        position
5056    }
5057
5058    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5059    where
5060        MBD: MultiBufferDimension
5061            + Ord
5062            + Sub<Output = MBD::TextDimension>
5063            + AddAssign<MBD::TextDimension>,
5064        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5065        I: 'a + IntoIterator<Item = &'a Anchor>,
5066    {
5067        let mut anchors = anchors.into_iter().peekable();
5068        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5069        let mut diff_transforms_cursor = self
5070            .diff_transforms
5071            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5072        diff_transforms_cursor.next();
5073
5074        let mut summaries = Vec::new();
5075        while let Some(anchor) = anchors.peek() {
5076            let target = anchor.seek_target(self);
5077            let excerpt_anchor = match anchor {
5078                Anchor::Min => {
5079                    summaries.push(MBD::default());
5080                    anchors.next();
5081                    continue;
5082                }
5083                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5084                Anchor::Max => {
5085                    summaries.push(MBD::from_summary(&self.text_summary()));
5086                    anchors.next();
5087                    continue;
5088                }
5089            };
5090
5091            cursor.seek_forward(&target, Bias::Left);
5092
5093            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5094            if let Some(excerpt) = cursor.item() {
5095                if !excerpt.contains(&excerpt_anchor) {
5096                    let position = self.summary_for_excerpt_position_without_hunks(
5097                        Bias::Left,
5098                        excerpt_start_position,
5099                        &mut diff_transforms_cursor,
5100                    );
5101                    summaries.push(position);
5102                    anchors.next();
5103                    continue;
5104                }
5105                let excerpt_buffer_start = excerpt
5106                    .range
5107                    .context
5108                    .start
5109                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5110                let excerpt_buffer_end = excerpt
5111                    .range
5112                    .context
5113                    .end
5114                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5115                for (buffer_summary, excerpt_anchor) in excerpt
5116                    .buffer
5117                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5118                        std::iter::from_fn(|| {
5119                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5120                            if !excerpt.contains(&excerpt_anchor) {
5121                                return None;
5122                            }
5123                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5124                        }),
5125                    )
5126                {
5127                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5128                    let mut position = excerpt_start_position;
5129                    if summary > excerpt_buffer_start {
5130                        position += summary - excerpt_buffer_start;
5131                    }
5132
5133                    if diff_transforms_cursor.start().0 < position {
5134                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5135                    }
5136
5137                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5138                        excerpt_anchor,
5139                        position,
5140                        &mut diff_transforms_cursor,
5141                        &excerpt.buffer,
5142                    ));
5143                }
5144            } else {
5145                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5146                let position = self.summary_for_excerpt_position_without_hunks(
5147                    Bias::Right,
5148                    excerpt_start_position,
5149                    &mut diff_transforms_cursor,
5150                );
5151                summaries.push(position);
5152                anchors.next();
5153            }
5154        }
5155
5156        summaries
5157    }
5158
5159    pub fn dimensions_from_points<'a, MBD>(
5160        &'a self,
5161        points: impl 'a + IntoIterator<Item = Point>,
5162    ) -> impl 'a + Iterator<Item = MBD>
5163    where
5164        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5165    {
5166        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5167        cursor.seek(&DimensionPair {
5168            key: Point::default(),
5169            value: None,
5170        });
5171        let mut points = points.into_iter();
5172        iter::from_fn(move || {
5173            let point = points.next()?;
5174
5175            cursor.seek_forward(&DimensionPair {
5176                key: point,
5177                value: None,
5178            });
5179
5180            if let Some(region) = cursor.region() {
5181                let overshoot = point - region.range.start.key;
5182                let buffer_point = region.buffer_range.start + overshoot;
5183                let mut position = region.range.start.value.unwrap();
5184                position.add_text_dim(
5185                    &region
5186                        .buffer
5187                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5188                );
5189                if point == region.range.end.key && region.has_trailing_newline {
5190                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5191                }
5192                Some(position)
5193            } else {
5194                Some(MBD::from_summary(&self.text_summary()))
5195            }
5196        })
5197    }
5198
5199    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5200    where
5201        I: 'a + IntoIterator<Item = &'a Anchor>,
5202    {
5203        let mut anchors = anchors.into_iter().enumerate().peekable();
5204        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5205        cursor.next();
5206
5207        let mut result = Vec::new();
5208
5209        while let Some((_, anchor)) = anchors.peek() {
5210            let old_excerpt_id = anchor.excerpt_id;
5211
5212            // Find the location where this anchor's excerpt should be.
5213            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5214            cursor.seek_forward(&Some(old_locator), Bias::Left);
5215
5216            let next_excerpt = cursor.item();
5217            let prev_excerpt = cursor.prev_item();
5218
5219            // Process all of the anchors for this excerpt.
5220            while let Some((anchor_ix, &anchor)) =
5221                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5222            {
5223                let mut anchor = anchor;
5224
5225                // Leave min and max anchors unchanged if invalid or
5226                // if the old excerpt still exists at this location
5227                let mut kept_position = next_excerpt
5228                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5229                    || old_excerpt_id == ExcerptId::max()
5230                    || old_excerpt_id == ExcerptId::min();
5231
5232                // If the old excerpt no longer exists at this location, then attempt to
5233                // find an equivalent position for this anchor in an adjacent excerpt.
5234                if !kept_position {
5235                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5236                        if excerpt.contains(&anchor) {
5237                            anchor.excerpt_id = excerpt.id;
5238                            kept_position = true;
5239                            break;
5240                        }
5241                    }
5242                }
5243
5244                // If there's no adjacent excerpt that contains the anchor's position,
5245                // then report that the anchor has lost its position.
5246                if !kept_position {
5247                    anchor = if let Some(excerpt) = next_excerpt {
5248                        let mut text_anchor = excerpt
5249                            .range
5250                            .context
5251                            .start
5252                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5253                        if text_anchor
5254                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5255                            .is_gt()
5256                        {
5257                            text_anchor = excerpt.range.context.end;
5258                        }
5259                        Anchor::text(excerpt.id, text_anchor)
5260                    } else if let Some(excerpt) = prev_excerpt {
5261                        let mut text_anchor = excerpt
5262                            .range
5263                            .context
5264                            .end
5265                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5266                        if text_anchor
5267                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5268                            .is_lt()
5269                        {
5270                            text_anchor = excerpt.range.context.start;
5271                        }
5272                        Anchor::text(excerpt.id, text_anchor)
5273                    } else if anchor.text_anchor.bias == Bias::Left {
5274                        Anchor::min()
5275                    } else {
5276                        Anchor::max()
5277                    };
5278                }
5279
5280                result.push((anchor_ix, anchor, kept_position));
5281            }
5282        }
5283        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5284        result
5285    }
5286
5287    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5288        self.anchor_at(position, Bias::Left)
5289    }
5290
5291    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5292        self.anchor_at(position, Bias::Right)
5293    }
5294
5295    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5296        let offset = position.to_offset(self);
5297
5298        // Find the given position in the diff transforms. Determine the corresponding
5299        // offset in the excerpts, and whether the position is within a deleted hunk.
5300        let mut diff_transforms = self
5301            .diff_transforms
5302            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5303        diff_transforms.seek(&offset, Bias::Right);
5304
5305        if offset == diff_transforms.start().0
5306            && bias == Bias::Left
5307            && let Some(prev_item) = diff_transforms.prev_item()
5308            && let DiffTransform::DeletedHunk { .. } = prev_item
5309        {
5310            diff_transforms.prev();
5311        }
5312        let offset_in_transform = offset - diff_transforms.start().0;
5313        let mut excerpt_offset = diff_transforms.start().1;
5314        let mut diff_base_anchor = None;
5315        if let Some(DiffTransform::DeletedHunk {
5316            buffer_id,
5317            base_text_byte_range,
5318            has_trailing_newline,
5319            ..
5320        }) = diff_transforms.item()
5321        {
5322            let diff = self.diffs.get(buffer_id).expect("missing diff");
5323            if offset_in_transform > base_text_byte_range.len() {
5324                debug_assert!(*has_trailing_newline);
5325                bias = Bias::Right;
5326            } else {
5327                diff_base_anchor = Some(
5328                    diff.base_text()
5329                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5330                );
5331                bias = Bias::Left;
5332            }
5333        } else {
5334            excerpt_offset += MultiBufferOffset(offset_in_transform);
5335        };
5336
5337        let mut excerpts = self
5338            .excerpts
5339            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5340        excerpts.seek(&excerpt_offset, Bias::Right);
5341        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5342            excerpts.prev();
5343        }
5344        if let Some(excerpt) = excerpts.item() {
5345            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5346            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5347                overshoot -= 1;
5348                bias = Bias::Right;
5349            }
5350
5351            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5352            let text_anchor =
5353                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5354            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5355            let anchor = match diff_base_anchor {
5356                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5357                None => anchor,
5358            };
5359            anchor.into()
5360        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5361        {
5362            Anchor::min()
5363        } else {
5364            Anchor::max()
5365        }
5366    }
5367
5368    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5369    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5370        let (excerpt, buffer, _) = self.as_singleton()?;
5371        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5372            Some(Anchor::in_buffer(excerpt, text_anchor))
5373        } else {
5374            None
5375        }
5376    }
5377
5378    /// Returns an anchor for the given excerpt and text anchor,
5379    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5380    pub fn anchor_range_in_excerpt(
5381        &self,
5382        excerpt_id: ExcerptId,
5383        text_anchor: Range<text::Anchor>,
5384    ) -> Option<Range<Anchor>> {
5385        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5386
5387        Some(
5388            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5389                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5390        )
5391    }
5392
5393    /// Returns an anchor for the given excerpt and text anchor,
5394    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5395    pub fn anchor_in_excerpt(
5396        &self,
5397        excerpt_id: ExcerptId,
5398        text_anchor: text::Anchor,
5399    ) -> Option<Anchor> {
5400        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5401        Self::anchor_in_excerpt_(excerpt, text_anchor)
5402    }
5403
5404    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5405    pub fn anchors_in_excerpt(
5406        &self,
5407        excerpt_id: ExcerptId,
5408        text_anchors: impl IntoIterator<Item = text::Anchor>,
5409    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5410        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5411        Some(
5412            text_anchors
5413                .into_iter()
5414                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5415        )
5416    }
5417
5418    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5419        match text_anchor.buffer_id {
5420            Some(buffer_id) if buffer_id == excerpt.buffer.remote_id() => (),
5421            Some(_) => return None,
5422            None if text_anchor.is_max() || text_anchor.is_min() => {
5423                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5424            }
5425            None => return None,
5426        }
5427
5428        let context = &excerpt.range.context;
5429        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5430            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5431        {
5432            return None;
5433        }
5434
5435        Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor))
5436    }
5437
5438    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5439        match anchor {
5440            // todo(lw): should be `!self.is_empty()`
5441            Anchor::Min | Anchor::Max => true,
5442            Anchor::Excerpt(excerpt_anchor) => {
5443                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5444                    return false;
5445                };
5446                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5447                cursor.seek(&target, Bias::Left);
5448                let Some(excerpt) = cursor.item() else {
5449                    return false;
5450                };
5451                excerpt.buffer.can_resolve(&excerpt_anchor.text_anchor())
5452            }
5453        }
5454    }
5455
5456    pub fn excerpts(
5457        &self,
5458    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5459        self.excerpts
5460            .iter()
5461            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5462    }
5463
5464    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5465    where
5466        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5467        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5468    {
5469        let excerpts = self.excerpts.cursor(());
5470        let diff_transforms = self.diff_transforms.cursor(());
5471        MultiBufferCursor {
5472            excerpts,
5473            diff_transforms,
5474            diffs: &self.diffs,
5475            cached_region: OnceCell::new(),
5476        }
5477    }
5478
5479    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5480        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5481        let mut excerpts = self
5482            .excerpts
5483            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5484        excerpts.seek(&Some(start_locator), Bias::Left);
5485        excerpts.prev();
5486
5487        let mut diff_transforms = self
5488            .diff_transforms
5489            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5490        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5491        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5492            diff_transforms.next();
5493        }
5494
5495        let excerpt = excerpts.item()?;
5496        Some(MultiBufferExcerpt {
5497            excerpt,
5498            offset: diff_transforms.start().output_dimension.0,
5499            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5500            excerpt_offset: excerpts.start().1,
5501            diff_transforms,
5502        })
5503    }
5504
5505    pub fn excerpt_boundaries_in_range<R, T>(
5506        &self,
5507        range: R,
5508    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5509    where
5510        R: RangeBounds<T>,
5511        T: ToOffset,
5512    {
5513        let start_offset;
5514        let start = match range.start_bound() {
5515            Bound::Included(start) => {
5516                start_offset = start.to_offset(self);
5517                Bound::Included(start_offset)
5518            }
5519            Bound::Excluded(_) => {
5520                panic!("not supported")
5521            }
5522            Bound::Unbounded => {
5523                start_offset = MultiBufferOffset::ZERO;
5524                Bound::Unbounded
5525            }
5526        };
5527        let end = match range.end_bound() {
5528            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5529            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5530            Bound::Unbounded => Bound::Unbounded,
5531        };
5532        let bounds = (start, end);
5533        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5534        cursor.seek(&DimensionPair {
5535            key: start_offset,
5536            value: None,
5537        });
5538
5539        if cursor
5540            .fetch_excerpt_with_range()
5541            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5542        {
5543            cursor.prev_excerpt();
5544        } else {
5545            cursor.seek_to_start_of_current_excerpt();
5546        }
5547        let mut prev_region = cursor
5548            .fetch_excerpt_with_range()
5549            .map(|(excerpt, _)| excerpt);
5550
5551        cursor.next_excerpt_forwards();
5552
5553        iter::from_fn(move || {
5554            loop {
5555                if self.singleton {
5556                    return None;
5557                }
5558
5559                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5560                cursor.next_excerpt_forwards();
5561                if !bounds.contains(&next_range.start.key) {
5562                    prev_region = Some(next_excerpt);
5563                    continue;
5564                }
5565
5566                let next_region_start = next_range.start.value.unwrap();
5567                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5568                    range.start.value.unwrap()
5569                } else {
5570                    self.max_point()
5571                };
5572
5573                let prev = prev_region.as_ref().map(|region| ExcerptBoundaryInfo {
5574                    id: region.id,
5575                    buffer: region.buffer.clone(),
5576                    buffer_id: region.buffer_id,
5577                    range: region.range.clone(),
5578                    end_row: MultiBufferRow(next_region_start.row),
5579                });
5580
5581                let next = ExcerptBoundaryInfo {
5582                    id: next_excerpt.id,
5583                    buffer: next_excerpt.buffer.clone(),
5584                    buffer_id: next_excerpt.buffer_id,
5585                    range: next_excerpt.range.clone(),
5586                    end_row: if next_excerpt.has_trailing_newline {
5587                        MultiBufferRow(next_region_end.row - 1)
5588                    } else {
5589                        MultiBufferRow(next_region_end.row)
5590                    },
5591                };
5592
5593                let row = MultiBufferRow(next_region_start.row);
5594
5595                prev_region = Some(next_excerpt);
5596
5597                return Some(ExcerptBoundary { row, prev, next });
5598            }
5599        })
5600    }
5601
5602    pub fn edit_count(&self) -> usize {
5603        self.edit_count
5604    }
5605
5606    pub fn non_text_state_update_count(&self) -> usize {
5607        self.non_text_state_update_count
5608    }
5609
5610    /// Returns the smallest enclosing bracket ranges containing the given range or
5611    /// None if no brackets contain range or the range is not contained in a single
5612    /// excerpt
5613    ///
5614    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5615    #[ztracing::instrument(skip_all)]
5616    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5617        &self,
5618        range: Range<T>,
5619        range_filter: Option<
5620            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5621        >,
5622    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5623        let range = range.start.to_offset(self)..range.end.to_offset(self);
5624        let mut excerpt = self.excerpt_containing(range.clone())?;
5625        let buffer = excerpt.buffer();
5626        let excerpt_buffer_range = excerpt.buffer_range();
5627
5628        // Filter to ranges contained in the excerpt
5629        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5630            excerpt_buffer_range.contains(&BufferOffset(open.start))
5631                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5632                && range_filter.is_none_or(|filter| {
5633                    filter(
5634                        buffer,
5635                        BufferOffset(open.start)..BufferOffset(close.end),
5636                        BufferOffset(close.start)..BufferOffset(close.end),
5637                    )
5638                })
5639        };
5640
5641        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5642            excerpt.map_range_to_buffer(range),
5643            Some(&range_filter),
5644        )?;
5645
5646        Some((
5647            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5648            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5649        ))
5650    }
5651
5652    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5653    /// not contained in a single excerpt
5654    pub fn enclosing_bracket_ranges<T: ToOffset>(
5655        &self,
5656        range: Range<T>,
5657    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5658    {
5659        let range = range.start.to_offset(self)..range.end.to_offset(self);
5660        let mut excerpt = self.excerpt_containing(range.clone())?;
5661
5662        Some(
5663            excerpt
5664                .buffer()
5665                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5666                .filter_map(move |pair| {
5667                    let open_range =
5668                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5669                    let close_range =
5670                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5671                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5672                        Some((
5673                            excerpt.map_range_from_buffer(open_range),
5674                            excerpt.map_range_from_buffer(close_range),
5675                        ))
5676                    } else {
5677                        None
5678                    }
5679                }),
5680        )
5681    }
5682
5683    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5684    /// not contained in a single excerpt
5685    pub fn text_object_ranges<T: ToOffset>(
5686        &self,
5687        range: Range<T>,
5688        options: TreeSitterOptions,
5689    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5690        let range = range.start.to_offset(self)..range.end.to_offset(self);
5691        self.excerpt_containing(range.clone())
5692            .map(|mut excerpt| {
5693                excerpt
5694                    .buffer()
5695                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5696                    .filter_map(move |(range, text_object)| {
5697                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5698                        if excerpt.contains_buffer_range(range.clone()) {
5699                            Some((excerpt.map_range_from_buffer(range), text_object))
5700                        } else {
5701                            None
5702                        }
5703                    })
5704            })
5705            .into_iter()
5706            .flatten()
5707    }
5708
5709    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5710    /// not contained in a single excerpt
5711    pub fn bracket_ranges<T: ToOffset>(
5712        &self,
5713        range: Range<T>,
5714    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5715    {
5716        let range = range.start.to_offset(self)..range.end.to_offset(self);
5717        let mut excerpt = self.excerpt_containing(range.clone())?;
5718        Some(
5719            excerpt
5720                .buffer()
5721                .bracket_ranges(excerpt.map_range_to_buffer(range))
5722                .filter_map(move |pair| {
5723                    let open_range =
5724                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5725                    let close_range =
5726                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5727                    excerpt
5728                        .contains_buffer_range(open_range.start..close_range.end)
5729                        .then(|| BracketMatch {
5730                            open_range: excerpt.map_range_from_buffer(open_range),
5731                            close_range: excerpt.map_range_from_buffer(close_range),
5732                            color_index: pair.color_index,
5733                            newline_only: pair.newline_only,
5734                            syntax_layer_depth: pair.syntax_layer_depth,
5735                        })
5736                })
5737                .map(BracketMatch::bracket_ranges),
5738        )
5739    }
5740
5741    pub fn redacted_ranges<'a, T: ToOffset>(
5742        &'a self,
5743        range: Range<T>,
5744        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5745    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5746        let range = range.start.to_offset(self)..range.end.to_offset(self);
5747        self.lift_buffer_metadata(range, move |buffer, range| {
5748            if redaction_enabled(buffer.file()) {
5749                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5750            } else {
5751                None
5752            }
5753        })
5754        .map(|(range, _, _)| range)
5755    }
5756
5757    pub fn runnable_ranges(
5758        &self,
5759        range: Range<Anchor>,
5760    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5761        let range = range.start.to_offset(self)..range.end.to_offset(self);
5762        self.lift_buffer_metadata(range, move |buffer, range| {
5763            Some(
5764                buffer
5765                    .runnable_ranges(range.clone())
5766                    .filter(move |runnable| {
5767                        runnable.run_range.start >= range.start
5768                            && runnable.run_range.end < range.end
5769                    })
5770                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5771            )
5772        })
5773        .map(|(run_range, runnable, _)| (run_range, runnable))
5774    }
5775
5776    pub fn line_indents(
5777        &self,
5778        start_row: MultiBufferRow,
5779        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5780    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5781        let max_point = self.max_point();
5782        let mut cursor = self.cursor::<Point, Point>();
5783        cursor.seek(&Point::new(start_row.0, 0));
5784        iter::from_fn(move || {
5785            let mut region = cursor.region()?;
5786            while !buffer_filter(&region.excerpt.buffer) {
5787                cursor.next();
5788                region = cursor.region()?;
5789            }
5790            let region = cursor.region()?;
5791            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5792            let buffer_start_row =
5793                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5794
5795            let buffer_end_row = if region.is_main_buffer
5796                && (region.has_trailing_newline || region.range.end == max_point)
5797            {
5798                region.buffer_range.end.row
5799            } else {
5800                region.buffer_range.end.row.saturating_sub(1)
5801            };
5802
5803            let line_indents = region
5804                .buffer
5805                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5806            let region_buffer_row = region.buffer_range.start.row;
5807            let region_row = region.range.start.row;
5808            let region_buffer = &region.excerpt.buffer;
5809            cursor.next();
5810            Some(line_indents.map(move |(buffer_row, indent)| {
5811                let row = region_row + (buffer_row - region_buffer_row);
5812                (MultiBufferRow(row), indent, region_buffer.as_ref())
5813            }))
5814        })
5815        .flatten()
5816    }
5817
5818    pub fn reversed_line_indents(
5819        &self,
5820        end_row: MultiBufferRow,
5821        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5822    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5823        let max_point = self.max_point();
5824        let mut cursor = self.cursor::<Point, Point>();
5825        cursor.seek(&Point::new(end_row.0, 0));
5826        iter::from_fn(move || {
5827            let mut region = cursor.region()?;
5828            while !buffer_filter(&region.excerpt.buffer) {
5829                cursor.prev();
5830                region = cursor.region()?;
5831            }
5832            let region = cursor.region()?;
5833
5834            let buffer_start_row = region.buffer_range.start.row;
5835            let buffer_end_row = if region.is_main_buffer
5836                && (region.has_trailing_newline || region.range.end == max_point)
5837            {
5838                region.buffer_range.end.row + 1
5839            } else {
5840                region.buffer_range.end.row
5841            };
5842
5843            let overshoot = end_row.0 - region.range.start.row;
5844            let buffer_end_row =
5845                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5846
5847            let line_indents = region
5848                .buffer
5849                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5850            let region_buffer_row = region.buffer_range.start.row;
5851            let region_row = region.range.start.row;
5852            let region_buffer = &region.excerpt.buffer;
5853            cursor.prev();
5854            Some(line_indents.map(move |(buffer_row, indent)| {
5855                let row = region_row + (buffer_row - region_buffer_row);
5856                (MultiBufferRow(row), indent, region_buffer.as_ref())
5857            }))
5858        })
5859        .flatten()
5860    }
5861
5862    pub async fn enclosing_indent(
5863        &self,
5864        mut target_row: MultiBufferRow,
5865    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5866        let max_row = MultiBufferRow(self.max_point().row);
5867        if target_row >= max_row {
5868            return None;
5869        }
5870
5871        let mut target_indent = self.line_indent_for_row(target_row);
5872
5873        // If the current row is at the start of an indented block, we want to return this
5874        // block as the enclosing indent.
5875        if !target_indent.is_line_empty() && target_row < max_row {
5876            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5877            if !next_line_indent.is_line_empty()
5878                && target_indent.raw_len() < next_line_indent.raw_len()
5879            {
5880                target_indent = next_line_indent;
5881                target_row.0 += 1;
5882            }
5883        }
5884
5885        const SEARCH_ROW_LIMIT: u32 = 25000;
5886        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5887        const YIELD_INTERVAL: u32 = 100;
5888
5889        let mut accessed_row_counter = 0;
5890
5891        // If there is a blank line at the current row, search for the next non indented lines
5892        if target_indent.is_line_empty() {
5893            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5894            let end =
5895                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5896
5897            let mut non_empty_line_above = None;
5898            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5899                if row < start {
5900                    break;
5901                }
5902                accessed_row_counter += 1;
5903                if accessed_row_counter == YIELD_INTERVAL {
5904                    accessed_row_counter = 0;
5905                    yield_now().await;
5906                }
5907                if !indent.is_line_empty() {
5908                    non_empty_line_above = Some((row, indent));
5909                    break;
5910                }
5911            }
5912
5913            let mut non_empty_line_below = None;
5914            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5915                if row > end {
5916                    break;
5917                }
5918                accessed_row_counter += 1;
5919                if accessed_row_counter == YIELD_INTERVAL {
5920                    accessed_row_counter = 0;
5921                    yield_now().await;
5922                }
5923                if !indent.is_line_empty() {
5924                    non_empty_line_below = Some((row, indent));
5925                    break;
5926                }
5927            }
5928
5929            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5930                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5931                    if above_indent.raw_len() >= below_indent.raw_len() {
5932                        (above_row, above_indent)
5933                    } else {
5934                        (below_row, below_indent)
5935                    }
5936                }
5937                (Some(above), None) => above,
5938                (None, Some(below)) => below,
5939                _ => return None,
5940            };
5941
5942            target_indent = indent;
5943            target_row = row;
5944        }
5945
5946        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5947        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5948
5949        let mut start_indent = None;
5950        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5951            if row < start {
5952                break;
5953            }
5954            accessed_row_counter += 1;
5955            if accessed_row_counter == YIELD_INTERVAL {
5956                accessed_row_counter = 0;
5957                yield_now().await;
5958            }
5959            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5960                start_indent = Some((row, indent));
5961                break;
5962            }
5963        }
5964        let (start_row, start_indent_size) = start_indent?;
5965
5966        let mut end_indent = (end, None);
5967        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5968            if row > end {
5969                break;
5970            }
5971            accessed_row_counter += 1;
5972            if accessed_row_counter == YIELD_INTERVAL {
5973                accessed_row_counter = 0;
5974                yield_now().await;
5975            }
5976            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5977                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5978                break;
5979            }
5980        }
5981        let (end_row, end_indent_size) = end_indent;
5982
5983        let indent = if let Some(end_indent_size) = end_indent_size {
5984            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5985                start_indent_size
5986            } else {
5987                end_indent_size
5988            }
5989        } else {
5990            start_indent_size
5991        };
5992
5993        Some((start_row..end_row, indent))
5994    }
5995
5996    pub fn indent_guides_in_range<T: ToPoint>(
5997        &self,
5998        range: Range<T>,
5999        ignore_disabled_for_language: bool,
6000        cx: &App,
6001    ) -> impl Iterator<Item = IndentGuide> {
6002        let range = range.start.to_point(self)..range.end.to_point(self);
6003        let start_row = MultiBufferRow(range.start.row);
6004        let end_row = MultiBufferRow(range.end.row);
6005
6006        let mut row_indents = self.line_indents(start_row, |buffer| {
6007            let settings =
6008                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6009            settings.indent_guides.enabled || ignore_disabled_for_language
6010        });
6011
6012        let mut result = Vec::new();
6013        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6014
6015        let mut prev_settings = None;
6016        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6017            if first_row > end_row {
6018                break;
6019            }
6020            let current_depth = indent_stack.len() as u32;
6021
6022            // Avoid retrieving the language settings repeatedly for every buffer row.
6023            if let Some((prev_buffer_id, _)) = &prev_settings
6024                && prev_buffer_id != &buffer.remote_id()
6025            {
6026                prev_settings.take();
6027            }
6028            let settings = &prev_settings
6029                .get_or_insert_with(|| {
6030                    (
6031                        buffer.remote_id(),
6032                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6033                    )
6034                })
6035                .1;
6036            let tab_size = settings.tab_size.get();
6037
6038            // When encountering empty, continue until found useful line indent
6039            // then add to the indent stack with the depth found
6040            let mut found_indent = false;
6041            let mut last_row = first_row;
6042            if line_indent.is_line_blank() {
6043                while !found_indent {
6044                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6045                        break;
6046                    };
6047                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6048                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6049                        break;
6050                    }
6051
6052                    if new_line_indent.is_line_blank() {
6053                        continue;
6054                    }
6055                    last_row = target_row.min(end_row);
6056                    line_indent = new_line_indent;
6057                    found_indent = true;
6058                    break;
6059                }
6060            } else {
6061                found_indent = true
6062            }
6063
6064            let depth = if found_indent {
6065                line_indent.len(tab_size) / tab_size
6066            } else {
6067                0
6068            };
6069
6070            match depth.cmp(&current_depth) {
6071                cmp::Ordering::Less => {
6072                    for _ in 0..(current_depth - depth) {
6073                        let mut indent = indent_stack.pop().unwrap();
6074                        if last_row != first_row {
6075                            // In this case, we landed on an empty row, had to seek forward,
6076                            // and discovered that the indent we where on is ending.
6077                            // This means that the last display row must
6078                            // be on line that ends this indent range, so we
6079                            // should display the range up to the first non-empty line
6080                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6081                        }
6082
6083                        result.push(indent)
6084                    }
6085                }
6086                cmp::Ordering::Greater => {
6087                    for next_depth in current_depth..depth {
6088                        indent_stack.push(IndentGuide {
6089                            buffer_id: buffer.remote_id(),
6090                            start_row: first_row,
6091                            end_row: last_row,
6092                            depth: next_depth,
6093                            tab_size,
6094                            settings: settings.indent_guides.clone(),
6095                        });
6096                    }
6097                }
6098                _ => {}
6099            }
6100
6101            for indent in indent_stack.iter_mut() {
6102                indent.end_row = last_row;
6103            }
6104        }
6105
6106        result.extend(indent_stack);
6107        result.into_iter()
6108    }
6109
6110    pub fn trailing_excerpt_update_count(&self) -> usize {
6111        self.trailing_excerpt_update_count
6112    }
6113
6114    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6115        self.point_to_buffer_offset(point)
6116            .and_then(|(buffer, _)| buffer.file())
6117    }
6118
6119    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6120        self.point_to_buffer_offset(offset)
6121            .and_then(|(buffer, offset)| buffer.language_at(offset))
6122    }
6123
6124    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6125        self.excerpts
6126            .first()
6127            .map(|excerpt| &excerpt.buffer)
6128            .map(|buffer| {
6129                language_settings(
6130                    buffer.language().map(|language| language.name()),
6131                    buffer.file(),
6132                    cx,
6133                )
6134            })
6135            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6136    }
6137
6138    pub fn language_settings_at<'a, T: ToOffset>(
6139        &'a self,
6140        point: T,
6141        cx: &'a App,
6142    ) -> Cow<'a, LanguageSettings> {
6143        let mut language = None;
6144        let mut file = None;
6145        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6146            language = buffer.language_at(offset);
6147            file = buffer.file();
6148        }
6149        language_settings(language.map(|l| l.name()), file, cx)
6150    }
6151
6152    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6153        self.point_to_buffer_offset(point)
6154            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6155    }
6156
6157    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6158        self.point_to_buffer_offset(point)
6159            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6160            .unwrap_or_default()
6161    }
6162
6163    pub fn language_indent_size_at<T: ToOffset>(
6164        &self,
6165        position: T,
6166        cx: &App,
6167    ) -> Option<IndentSize> {
6168        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6169        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6170    }
6171
6172    pub fn is_dirty(&self) -> bool {
6173        self.is_dirty
6174    }
6175
6176    pub fn has_deleted_file(&self) -> bool {
6177        self.has_deleted_file
6178    }
6179
6180    pub fn has_conflict(&self) -> bool {
6181        self.has_conflict
6182    }
6183
6184    pub fn has_diagnostics(&self) -> bool {
6185        self.excerpts
6186            .iter()
6187            .any(|excerpt| excerpt.buffer.has_diagnostics())
6188    }
6189
6190    pub fn diagnostic_group(
6191        &self,
6192        buffer_id: BufferId,
6193        group_id: usize,
6194    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6195        self.lift_buffer_metadata::<Point, _, _>(
6196            Point::zero()..self.max_point(),
6197            move |buffer, range| {
6198                if buffer.remote_id() != buffer_id {
6199                    return None;
6200                };
6201                Some(
6202                    buffer
6203                        .diagnostics_in_range(range, false)
6204                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6205                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6206                )
6207            },
6208        )
6209        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6210    }
6211
6212    pub fn diagnostics_in_range<'a, MBD>(
6213        &'a self,
6214        range: Range<MBD>,
6215    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6216    where
6217        MBD::TextDimension: 'a
6218            + text::ToOffset
6219            + text::FromAnchor
6220            + Sub<Output = MBD::TextDimension>
6221            + fmt::Debug
6222            + ops::Add<Output = MBD::TextDimension>
6223            + ops::AddAssign
6224            + Ord,
6225        MBD: MultiBufferDimension
6226            + Ord
6227            + Sub<Output = MBD::TextDimension>
6228            + ops::Add<MBD::TextDimension, Output = MBD>
6229            + ops::AddAssign<MBD::TextDimension>
6230            + 'a,
6231    {
6232        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6233            Some(
6234                buffer
6235                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6236                    .map(|entry| (entry.range, entry.diagnostic)),
6237            )
6238        })
6239        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6240    }
6241
6242    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6243        &'a self,
6244        range: Range<MBD>,
6245    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6246    where
6247        MBD: MultiBufferDimension
6248            + Ord
6249            + Sub<Output = MBD::TextDimension>
6250            + ops::Add<MBD::TextDimension, Output = MBD>
6251            + ops::AddAssign<MBD::TextDimension>,
6252        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6253            + ops::Add<Output = MBD::TextDimension>
6254            + text::ToOffset
6255            + text::FromAnchor
6256            + AddAssign<MBD::TextDimension>
6257            + Ord,
6258    {
6259        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6260            Some(
6261                buffer
6262                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6263                    .map(|entry| (entry.range, entry.diagnostic)),
6264            )
6265        })
6266        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6267    }
6268
6269    pub fn syntax_ancestor<T: ToOffset>(
6270        &self,
6271        range: Range<T>,
6272    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6273        let range = range.start.to_offset(self)..range.end.to_offset(self);
6274        let mut excerpt = self.excerpt_containing(range.clone())?;
6275        let node = excerpt
6276            .buffer()
6277            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6278        let node_range = node.byte_range();
6279        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6280        if !excerpt.contains_buffer_range(node_range.clone()) {
6281            return None;
6282        };
6283        Some((node, excerpt.map_range_from_buffer(node_range)))
6284    }
6285
6286    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6287        let (excerpt_id, _, buffer) = self.as_singleton()?;
6288        let outline = buffer.outline(theme);
6289        Some(Outline::new(
6290            outline
6291                .items
6292                .into_iter()
6293                .flat_map(|item| {
6294                    Some(OutlineItem {
6295                        depth: item.depth,
6296                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6297                        source_range_for_text: self
6298                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6299                        text: item.text,
6300                        highlight_ranges: item.highlight_ranges,
6301                        name_ranges: item.name_ranges,
6302                        body_range: item.body_range.and_then(|body_range| {
6303                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6304                        }),
6305                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6306                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6307                        }),
6308                    })
6309                })
6310                .collect(),
6311        ))
6312    }
6313
6314    pub fn symbols_containing<T: ToOffset>(
6315        &self,
6316        offset: T,
6317        theme: Option<&SyntaxTheme>,
6318    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6319        let anchor = self.anchor_before(offset);
6320        let excerpt @ &Excerpt {
6321            id: excerpt_id,
6322            buffer_id,
6323            ref buffer,
6324            ..
6325        } = self.excerpt(anchor.excerpt_id)?;
6326        if cfg!(debug_assertions) {
6327            match anchor.text_anchor.buffer_id {
6328                // we clearly are hitting this according to sentry, but in what situations can this occur?
6329                Some(anchor_buffer_id) => {
6330                    assert_eq!(
6331                        anchor_buffer_id, buffer_id,
6332                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6333                    )
6334                }
6335                None => assert!(anchor.is_max()),
6336            }
6337        };
6338        Some((
6339            buffer_id,
6340            buffer
6341                .symbols_containing(anchor.text_anchor, theme)
6342                .into_iter()
6343                .flat_map(|item| {
6344                    Some(OutlineItem {
6345                        depth: item.depth,
6346                        source_range_for_text: Anchor::range_in_buffer(
6347                            excerpt_id,
6348                            item.source_range_for_text,
6349                        ),
6350                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6351                        text: item.text,
6352                        highlight_ranges: item.highlight_ranges,
6353                        name_ranges: item.name_ranges,
6354                        body_range: item
6355                            .body_range
6356                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6357                        annotation_range: item
6358                            .annotation_range
6359                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6360                    })
6361                })
6362                .collect(),
6363        ))
6364    }
6365
6366    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6367        todo!()
6368    }
6369
6370    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6371        self.path_keys_by_buffer.get(&buffer_id)
6372    }
6373
6374    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6375        self.buffer_for_path(self.path_keys_by_buffer.get(&id)?)
6376    }
6377
6378    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6379        self.path_keys_by_index.get(&anchor.path).cloned()
6380    }
6381
6382    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6383        self.try_path_for_anchor(anchor)
6384            .expect("invalid anchor: path was never added to multibuffer")
6385    }
6386
6387    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6388        let mut cursor = self
6389            .excerpts
6390            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6391        let locator = self.excerpt_locator_for_id(excerpt_id);
6392        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6393        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6394            sought_exact = true;
6395            cursor.prev();
6396        } else if excerpt_id == ExcerptId::min() {
6397            sought_exact = true;
6398        }
6399        if sought_exact {
6400            let start = cursor.start().1;
6401            let end = cursor.end().1;
6402            let mut diff_transforms = self
6403                .diff_transforms
6404                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6405            diff_transforms.seek(&start, Bias::Left);
6406            let overshoot = start - diff_transforms.start().0;
6407            let start = diff_transforms.start().1 + overshoot;
6408            diff_transforms.seek(&end, Bias::Right);
6409            let overshoot = end - diff_transforms.start().0;
6410            let end = diff_transforms.start().1 + overshoot;
6411            Some(start.0..end.0)
6412        } else {
6413            None
6414        }
6415    }
6416
6417    // todo!() sort out excerpt_containing etc.
6418    fn excerpt_at(&self, position: impl ToOffset) -> Option<&Excerpt> {
6419        todo!()
6420    }
6421
6422    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6423    pub fn excerpt_containing<T: ToOffset>(
6424        &self,
6425        range: Range<T>,
6426    ) -> Option<MultiBufferExcerpt<'_>> {
6427        let range = range.start.to_offset(self)..range.end.to_offset(self);
6428        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6429        cursor.seek(&range.start);
6430
6431        let start_excerpt = cursor.excerpt()?;
6432        if range.end != range.start {
6433            cursor.seek_forward(&range.end);
6434            if cursor.excerpt()?.id != start_excerpt.id {
6435                return None;
6436            }
6437        }
6438
6439        cursor.seek_to_start_of_current_excerpt();
6440        let region = cursor.region()?;
6441        let offset = region.range.start;
6442        let buffer_offset = start_excerpt.buffer_start_offset();
6443        let excerpt_offset = *cursor.excerpts.start();
6444        Some(MultiBufferExcerpt {
6445            diff_transforms: cursor.diff_transforms,
6446            excerpt: start_excerpt,
6447            offset,
6448            buffer_offset,
6449            excerpt_offset,
6450        })
6451    }
6452
6453    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6454        match anchor {
6455            Anchor::Min => self
6456                .excerpts
6457                .first()
6458                .map(|excerpt| excerpt.buffer.remote_id()),
6459            Anchor::Excerpt(excerpt_anchor) => Some(excerpt_anchor.buffer_id),
6460            Anchor::Max => self
6461                .excerpts
6462                .last()
6463                .map(|excerpt| excerpt.buffer.remote_id()),
6464        }
6465    }
6466
6467    pub fn selections_in_range<'a>(
6468        &'a self,
6469        range: &'a Range<Anchor>,
6470        include_local: bool,
6471    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6472        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6473        cursor.seek(&range.start.seek_target(self), Bias::Left);
6474        cursor
6475            .take_while(move |excerpt| {
6476                let excerpt_start =
6477                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6478                excerpt_start.cmp(&range.end, self).is_le()
6479            })
6480            .flat_map(move |excerpt| {
6481                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6482                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6483                    && excerpt.contains(&excerpt_anchor)
6484                {
6485                    query_range.start = excerpt_anchor.text_anchor();
6486                }
6487                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6488                    && excerpt.contains(&excerpt_anchor)
6489                {
6490                    query_range.end = excerpt_anchor.text_anchor();
6491                }
6492
6493                excerpt
6494                    .buffer
6495                    .selections_in_range(query_range, include_local)
6496                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6497                        selections.map(move |selection| {
6498                            let mut start =
6499                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6500                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6501                            if range.start.cmp(&start, self).is_gt() {
6502                                start = range.start;
6503                            }
6504                            if range.end.cmp(&end, self).is_lt() {
6505                                end = range.end;
6506                            }
6507
6508                            (
6509                                replica_id,
6510                                line_mode,
6511                                cursor_shape,
6512                                Selection {
6513                                    id: selection.id,
6514                                    start,
6515                                    end,
6516                                    reversed: selection.reversed,
6517                                    goal: selection.goal,
6518                                },
6519                            )
6520                        })
6521                    })
6522            })
6523    }
6524
6525    pub fn show_headers(&self) -> bool {
6526        self.show_headers
6527    }
6528
6529    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6530        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6531    }
6532
6533    pub fn all_diff_hunks_expanded(&self) -> bool {
6534        self.all_diff_hunks_expanded
6535    }
6536
6537    /// Visually annotates a position or range with the `Debug` representation of a value. The
6538    /// callsite of this function is used as a key - previous annotations will be removed.
6539    #[cfg(debug_assertions)]
6540    #[track_caller]
6541    pub fn debug<V, R>(&self, ranges: &R, value: V)
6542    where
6543        R: debug::ToMultiBufferDebugRanges,
6544        V: std::fmt::Debug,
6545    {
6546        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6547    }
6548
6549    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6550    /// debug annotations with the same key will be removed. The key is also used to determine the
6551    /// annotation's color.
6552    #[cfg(debug_assertions)]
6553    #[track_caller]
6554    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6555    where
6556        K: std::hash::Hash + 'static,
6557        R: debug::ToMultiBufferDebugRanges,
6558        V: std::fmt::Debug,
6559    {
6560        let text_ranges = ranges
6561            .to_multi_buffer_debug_ranges(self)
6562            .into_iter()
6563            .flat_map(|range| {
6564                self.range_to_buffer_ranges(range.start..=range.end)
6565                    .into_iter()
6566                    .map(|(buffer, range, _excerpt_id)| {
6567                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6568                    })
6569            })
6570            .collect();
6571        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6572            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6573        });
6574    }
6575
6576    fn excerpt_edits_for_diff_change(
6577        &self,
6578        path: &PathKey,
6579        diff_change_range: Range<usize>,
6580    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6581        let mut excerpt_edits = Vec::new();
6582        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6583        cursor.seek(path, Bias::Left);
6584        while let Some(excerpt) = cursor.item()
6585            && &excerpt.path_key == path
6586        {
6587            let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6588            let excerpt_start = cursor.start().clone();
6589            let excerpt_len = excerpt.text_summary.len;
6590            cursor.next();
6591            if diff_change_range.end < excerpt_buffer_range.start
6592                || diff_change_range.start > excerpt_buffer_range.end
6593            {
6594                continue;
6595            }
6596            let diff_change_start_in_excerpt = diff_change_range
6597                .start
6598                .saturating_sub(excerpt_buffer_range.start);
6599            let diff_change_end_in_excerpt = diff_change_range
6600                .end
6601                .saturating_sub(excerpt_buffer_range.start);
6602            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6603            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6604            excerpt_edits.push(Edit {
6605                old: edit_start..edit_end,
6606                new: edit_start..edit_end,
6607            });
6608        }
6609        excerpt_edits
6610    }
6611
6612    fn excerpt_ranges_for_path(
6613        &self,
6614        path_key: &PathKey,
6615    ) -> impl Iterator<Item = ExcerptRange<text::Anchor>> {
6616        todo!()
6617    }
6618}
6619
6620#[cfg(any(test, feature = "test-support"))]
6621impl MultiBufferSnapshot {
6622    pub fn random_byte_range(
6623        &self,
6624        start_offset: MultiBufferOffset,
6625        rng: &mut impl rand::Rng,
6626    ) -> Range<MultiBufferOffset> {
6627        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6628        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6629        start..end
6630    }
6631
6632    #[cfg(any(test, feature = "test-support"))]
6633    fn check_invariants(&self) {
6634        let excerpts = self.excerpts.items(());
6635        let excerpt_ids = self.excerpt_ids.items(());
6636
6637        for (ix, excerpt) in excerpts.iter().enumerate() {
6638            if ix == 0 {
6639                if excerpt.locator <= Locator::min() {
6640                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6641                }
6642            } else if excerpt.locator <= excerpts[ix - 1].locator {
6643                panic!("excerpts are out-of-order: {:?}", excerpts);
6644            }
6645        }
6646
6647        for (ix, entry) in excerpt_ids.iter().enumerate() {
6648            if ix == 0 {
6649                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6650                    panic!("invalid first excerpt id {:?}", entry.id);
6651                }
6652            } else if entry.id <= excerpt_ids[ix - 1].id {
6653                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6654            }
6655        }
6656
6657        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6658            panic!(
6659                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6660                self.excerpts.summary().text,
6661                self.diff_transforms.summary().input,
6662                self.diff_transforms.items(()),
6663            );
6664        }
6665
6666        let mut prev_transform: Option<&DiffTransform> = None;
6667        for item in self.diff_transforms.iter() {
6668            if let DiffTransform::BufferContent {
6669                summary,
6670                inserted_hunk_info,
6671            } = item
6672            {
6673                if let Some(DiffTransform::BufferContent {
6674                    inserted_hunk_info: prev_inserted_hunk_info,
6675                    ..
6676                }) = prev_transform
6677                    && *inserted_hunk_info == *prev_inserted_hunk_info
6678                {
6679                    panic!(
6680                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6681                        self.diff_transforms.items(())
6682                    );
6683                }
6684                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6685                    panic!("empty buffer content transform");
6686                }
6687            }
6688            prev_transform = Some(item);
6689        }
6690    }
6691}
6692
6693impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6694where
6695    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6696    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6697{
6698    #[instrument(skip_all)]
6699    fn seek(&mut self, position: &MBD) {
6700        let position = OutputDimension(*position);
6701        self.cached_region.take();
6702        self.diff_transforms.seek(&position, Bias::Right);
6703        if self.diff_transforms.item().is_none()
6704            && self.diff_transforms.start().output_dimension == position
6705        {
6706            self.diff_transforms.prev();
6707        }
6708
6709        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6710        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6711            let overshoot = position - self.diff_transforms.start().output_dimension;
6712            excerpt_position += overshoot;
6713        }
6714
6715        self.excerpts.seek(&excerpt_position, Bias::Right);
6716        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6717            self.excerpts.prev();
6718        }
6719    }
6720
6721    fn seek_forward(&mut self, position: &MBD) {
6722        let position = OutputDimension(*position);
6723        self.cached_region.take();
6724        self.diff_transforms.seek_forward(&position, Bias::Right);
6725        if self.diff_transforms.item().is_none()
6726            && self.diff_transforms.start().output_dimension == position
6727        {
6728            self.diff_transforms.prev();
6729        }
6730
6731        let overshoot = position - self.diff_transforms.start().output_dimension;
6732        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6733        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6734            excerpt_position += overshoot;
6735        }
6736
6737        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6738        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6739            self.excerpts.prev();
6740        }
6741    }
6742
6743    fn next_excerpt(&mut self) {
6744        self.excerpts.next();
6745        self.seek_to_start_of_current_excerpt();
6746    }
6747
6748    fn prev_excerpt(&mut self) {
6749        self.excerpts.prev();
6750        self.seek_to_start_of_current_excerpt();
6751    }
6752
6753    fn seek_to_start_of_current_excerpt(&mut self) {
6754        self.cached_region.take();
6755
6756        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6757            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6758            && self.diff_transforms.next_item().is_some()
6759        {
6760            self.diff_transforms.next();
6761        }
6762    }
6763
6764    fn next_excerpt_forwards(&mut self) {
6765        self.excerpts.next();
6766        self.seek_to_start_of_current_excerpt_forward();
6767    }
6768
6769    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6770        self.cached_region.take();
6771
6772        if self
6773            .diff_transforms
6774            .seek_forward(self.excerpts.start(), Bias::Left)
6775            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6776            && self.diff_transforms.next_item().is_some()
6777        {
6778            self.diff_transforms.next();
6779        }
6780    }
6781
6782    fn next(&mut self) {
6783        self.cached_region.take();
6784        match self
6785            .diff_transforms
6786            .end()
6787            .excerpt_dimension
6788            .cmp(&self.excerpts.end())
6789        {
6790            cmp::Ordering::Less => self.diff_transforms.next(),
6791            cmp::Ordering::Greater => self.excerpts.next(),
6792            cmp::Ordering::Equal => {
6793                self.diff_transforms.next();
6794                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6795                    || self.diff_transforms.item().is_none()
6796                {
6797                    self.excerpts.next();
6798                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6799                    self.diff_transforms.item()
6800                    && self
6801                        .excerpts
6802                        .item()
6803                        .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end)
6804                {
6805                    self.excerpts.next();
6806                }
6807            }
6808        }
6809    }
6810
6811    fn prev(&mut self) {
6812        self.cached_region.take();
6813        match self
6814            .diff_transforms
6815            .start()
6816            .excerpt_dimension
6817            .cmp(self.excerpts.start())
6818        {
6819            cmp::Ordering::Less => self.excerpts.prev(),
6820            cmp::Ordering::Greater => self.diff_transforms.prev(),
6821            cmp::Ordering::Equal => {
6822                self.diff_transforms.prev();
6823                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6824                    || self.diff_transforms.item().is_none()
6825                {
6826                    self.excerpts.prev();
6827                }
6828            }
6829        }
6830    }
6831
6832    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
6833        self.cached_region
6834            .get_or_init(|| self.build_region())
6835            .as_ref()
6836    }
6837
6838    fn is_at_start_of_excerpt(&mut self) -> bool {
6839        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6840            return false;
6841        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6842            return true;
6843        }
6844
6845        self.diff_transforms.prev();
6846        let prev_transform = self.diff_transforms.item();
6847        self.diff_transforms.next();
6848
6849        prev_transform.is_none_or(|next_transform| {
6850            matches!(next_transform, DiffTransform::BufferContent { .. })
6851        })
6852    }
6853
6854    fn is_at_end_of_excerpt(&self) -> bool {
6855        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6856            return false;
6857        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6858            || self.diff_transforms.item().is_none()
6859        {
6860            return true;
6861        }
6862
6863        let next_transform = self.diff_transforms.next_item();
6864        next_transform.is_none_or(|next_transform| match next_transform {
6865            DiffTransform::BufferContent { .. } => true,
6866            DiffTransform::DeletedHunk { hunk_info, .. } => self
6867                .excerpts
6868                .item()
6869                .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end),
6870        })
6871    }
6872
6873    fn main_buffer_position(&self) -> Option<BD> {
6874        let excerpt = self.excerpts.item()?;
6875        let buffer = &excerpt.buffer;
6876        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6877        let mut buffer_start = buffer_context_start;
6878        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6879        buffer_start += overshoot;
6880        Some(buffer_start)
6881    }
6882
6883    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6884        let excerpt = self.excerpts.item()?;
6885        match self.diff_transforms.item()? {
6886            DiffTransform::DeletedHunk {
6887                buffer_id,
6888                base_text_byte_range,
6889                has_trailing_newline,
6890                hunk_info,
6891                ..
6892            } => {
6893                let diff = self.diffs.get(buffer_id)?;
6894                let buffer = diff.base_text();
6895                let mut rope_cursor = buffer.as_rope().cursor(0);
6896                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6897                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6898                let mut buffer_end = buffer_start;
6899                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6900                let start = self.diff_transforms.start().output_dimension.0;
6901                let end = self.diff_transforms.end().output_dimension.0;
6902                Some(MultiBufferRegion {
6903                    buffer,
6904                    excerpt,
6905                    has_trailing_newline: *has_trailing_newline,
6906                    is_main_buffer: false,
6907                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6908                        hunk_info.hunk_secondary_status,
6909                    )),
6910                    buffer_range: buffer_start..buffer_end,
6911                    range: start..end,
6912                })
6913            }
6914            DiffTransform::BufferContent {
6915                inserted_hunk_info, ..
6916            } => {
6917                let buffer = &excerpt.buffer;
6918                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6919
6920                let mut start = self.diff_transforms.start().output_dimension.0;
6921                let mut buffer_start = buffer_context_start;
6922                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6923                    let overshoot =
6924                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6925                    start += overshoot;
6926                } else {
6927                    let overshoot =
6928                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6929                    buffer_start += overshoot;
6930                }
6931
6932                let mut end;
6933                let mut buffer_end;
6934                let has_trailing_newline;
6935                let transform_end = self.diff_transforms.end();
6936                if transform_end.excerpt_dimension < self.excerpts.end() {
6937                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
6938                    end = transform_end.output_dimension.0;
6939                    buffer_end = buffer_context_start;
6940                    buffer_end += overshoot;
6941                    has_trailing_newline = false;
6942                } else {
6943                    let overshoot =
6944                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6945                    end = self.diff_transforms.start().output_dimension.0;
6946                    end += overshoot;
6947                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6948                    has_trailing_newline = excerpt.has_trailing_newline;
6949                };
6950
6951                let diff_hunk_status = inserted_hunk_info.map(|info| {
6952                    if info.is_logically_deleted {
6953                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6954                    } else {
6955                        DiffHunkStatus::added(info.hunk_secondary_status)
6956                    }
6957                });
6958
6959                Some(MultiBufferRegion {
6960                    buffer,
6961                    excerpt,
6962                    has_trailing_newline,
6963                    is_main_buffer: true,
6964                    diff_hunk_status,
6965                    buffer_range: buffer_start..buffer_end,
6966                    range: start..end,
6967                })
6968            }
6969        }
6970    }
6971
6972    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
6973        let excerpt = self.excerpts.item()?;
6974        match self.diff_transforms.item()? {
6975            &DiffTransform::DeletedHunk { .. } => {
6976                let start = self.diff_transforms.start().output_dimension.0;
6977                let end = self.diff_transforms.end().output_dimension.0;
6978                Some((excerpt, start..end))
6979            }
6980            DiffTransform::BufferContent { .. } => {
6981                let mut start = self.diff_transforms.start().output_dimension.0;
6982                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6983                    let overshoot =
6984                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6985                    start += overshoot;
6986                }
6987
6988                let mut end;
6989                let transform_end = self.diff_transforms.end();
6990                if transform_end.excerpt_dimension < self.excerpts.end() {
6991                    end = transform_end.output_dimension.0;
6992                } else {
6993                    let overshoot =
6994                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6995                    end = self.diff_transforms.start().output_dimension.0;
6996                    end += overshoot;
6997                };
6998
6999                Some((excerpt, start..end))
7000            }
7001        }
7002    }
7003
7004    fn excerpt(&self) -> Option<&'a Excerpt> {
7005        self.excerpts.item()
7006    }
7007}
7008
7009impl Excerpt {
7010    fn new(
7011        path_key: PathKey,
7012        buffer: Arc<BufferSnapshot>,
7013        range: ExcerptRange<text::Anchor>,
7014        has_trailing_newline: bool,
7015    ) -> Self {
7016        Excerpt {
7017            path_key,
7018            max_buffer_row: range.context.end.to_point(&buffer).row,
7019            text_summary: buffer
7020                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7021            buffer,
7022            range,
7023            has_trailing_newline,
7024        }
7025    }
7026
7027    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7028        let content_start = self.range.context.start.to_offset(&self.buffer);
7029        let chunks_start = content_start + range.start;
7030        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7031
7032        let has_footer = self.has_trailing_newline
7033            && range.start <= self.text_summary.len
7034            && range.end > self.text_summary.len;
7035
7036        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7037
7038        ExcerptChunks {
7039            content_chunks,
7040            has_footer,
7041            end: self.end_anchor(),
7042        }
7043    }
7044
7045    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7046        let content_start = self.range.context.start.to_offset(&self.buffer);
7047        let chunks_start = content_start + range.start;
7048        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7049        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7050        excerpt_chunks.has_footer = self.has_trailing_newline
7051            && range.start <= self.text_summary.len
7052            && range.end > self.text_summary.len;
7053    }
7054
7055    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7056        if text_anchor
7057            .cmp(&self.range.context.start, &self.buffer)
7058            .is_lt()
7059        {
7060            self.range.context.start
7061        } else if text_anchor
7062            .cmp(&self.range.context.end, &self.buffer)
7063            .is_gt()
7064        {
7065            self.range.context.end
7066        } else {
7067            text_anchor
7068        }
7069    }
7070
7071    pub(crate) fn contains(&self, anchor: &ExcerptAnchor) -> bool {
7072        self.path_key_index == anchor.path
7073            && self.buffer.remote_id() == anchor.buffer_id
7074            && self.range.contains(&anchor.text_anchor(), &self.buffer)
7075    }
7076
7077    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7078    fn buffer_start_offset(&self) -> BufferOffset {
7079        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7080    }
7081
7082    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7083    fn buffer_end_offset(&self) -> BufferOffset {
7084        self.buffer_start_offset() + self.text_summary.len
7085    }
7086
7087    fn start_anchor(&self) -> ExcerptAnchor {
7088        todo!()
7089    }
7090
7091    fn end_anchor(&self) -> ExcerptAnchor {
7092        todo!()
7093    }
7094}
7095
7096impl PartialEq for Excerpt {
7097    fn eq(&self, other: &Self) -> bool {
7098        self.buffer.remote_id() == other.buffer.remote_id()
7099            && self.range.context == other.range.context
7100    }
7101}
7102
7103impl<'a> MultiBufferExcerpt<'a> {
7104    pub fn buffer_id(&self) -> BufferId {
7105        self.excerpt.buffer.remote_id()
7106    }
7107
7108    pub fn start_anchor(&self) -> Anchor {
7109        Anchor::in_buffer(
7110            self.excerpt.path_key_index,
7111            self.excerpt.range.context.start,
7112        )
7113    }
7114
7115    pub fn end_anchor(&self) -> Anchor {
7116        Anchor::in_buffer(self.excerpt.path_key_index, self.excerpt.range.context.end)
7117    }
7118
7119    pub fn buffer(&self) -> &'a BufferSnapshot {
7120        &self.excerpt.buffer
7121    }
7122
7123    pub fn buffer_range(&self) -> Range<BufferOffset> {
7124        self.buffer_offset
7125            ..BufferOffset(
7126                self.excerpt
7127                    .range
7128                    .context
7129                    .end
7130                    .to_offset(&self.excerpt.buffer.text),
7131            )
7132    }
7133
7134    pub fn start_offset(&self) -> MultiBufferOffset {
7135        self.offset
7136    }
7137
7138    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7139    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7140        self.map_range_to_buffer(offset..offset).start
7141    }
7142
7143    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7144    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7145        self.diff_transforms
7146            .seek(&OutputDimension(range.start), Bias::Right);
7147        let start = self.map_offset_to_buffer_internal(range.start);
7148        let end = if range.end > range.start {
7149            self.diff_transforms
7150                .seek_forward(&OutputDimension(range.end), Bias::Right);
7151            self.map_offset_to_buffer_internal(range.end)
7152        } else {
7153            start
7154        };
7155        start..end
7156    }
7157
7158    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7159        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7160        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7161            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7162        };
7163        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7164        self.buffer_offset + offset_in_excerpt
7165    }
7166
7167    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7168    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7169        self.map_range_from_buffer(buffer_offset..buffer_offset)
7170            .start
7171    }
7172
7173    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7174    pub fn map_range_from_buffer(
7175        &mut self,
7176        buffer_range: Range<BufferOffset>,
7177    ) -> Range<MultiBufferOffset> {
7178        if buffer_range.start < self.buffer_offset {
7179            log::warn!(
7180                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7181            );
7182            return self.offset..self.offset;
7183        }
7184        let overshoot = buffer_range.start - self.buffer_offset;
7185        let excerpt_offset = self.excerpt_offset + overshoot;
7186        let excerpt_seek_dim = excerpt_offset;
7187        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7188        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7189            log::warn!(
7190                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7191            );
7192            return self.offset..self.offset;
7193        }
7194        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7195        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7196
7197        let end = if buffer_range.start < buffer_range.end {
7198            let overshoot = buffer_range.end - self.buffer_offset;
7199            let excerpt_offset = self.excerpt_offset + overshoot;
7200            let excerpt_seek_dim = excerpt_offset;
7201            self.diff_transforms
7202                .seek_forward(&excerpt_seek_dim, Bias::Right);
7203            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7204            // todo(lw): Clamp end to the excerpt boundaries
7205            self.diff_transforms.start().output_dimension.0 + overshoot
7206        } else {
7207            start
7208        };
7209
7210        start..end
7211    }
7212
7213    /// Returns true if the entirety of the given range is in the buffer's excerpt
7214    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7215        range.start >= self.excerpt.buffer_start_offset()
7216            && range.end <= self.excerpt.buffer_end_offset()
7217    }
7218
7219    /// Returns true if any part of the given range is in the buffer's excerpt
7220    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7221        range.start <= self.excerpt.buffer_end_offset()
7222            && range.end >= self.excerpt.buffer_start_offset()
7223    }
7224
7225    pub fn max_buffer_row(&self) -> u32 {
7226        self.excerpt.max_buffer_row
7227    }
7228}
7229
7230impl fmt::Debug for Excerpt {
7231    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7232        f.debug_struct("Excerpt")
7233            .field("path_key", &self.path_key)
7234            .field("range", &self.range)
7235            .field("text_summary", &self.text_summary)
7236            .field("has_trailing_newline", &self.has_trailing_newline)
7237            .finish()
7238    }
7239}
7240
7241impl sum_tree::Item for Excerpt {
7242    type Summary = ExcerptSummary;
7243
7244    fn summary(&self, _cx: ()) -> Self::Summary {
7245        let mut text = self.text_summary;
7246        if self.has_trailing_newline {
7247            text += TextSummary::from("\n");
7248        }
7249        ExcerptSummary {
7250            path_key: self.path_key,
7251            max_anchor: self.range.context.end,
7252            widest_line_number: self.max_buffer_row,
7253            text: text.into(),
7254            count: 1,
7255        }
7256    }
7257}
7258
7259impl DiffTransform {
7260    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7261        match self {
7262            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7263            DiffTransform::BufferContent {
7264                inserted_hunk_info, ..
7265            } => *inserted_hunk_info,
7266        }
7267    }
7268}
7269
7270impl sum_tree::Item for DiffTransform {
7271    type Summary = DiffTransformSummary;
7272
7273    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7274        match self {
7275            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7276                input: *summary,
7277                output: *summary,
7278            },
7279            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7280                input: MBTextSummary::default(),
7281                output: summary.into(),
7282            },
7283        }
7284    }
7285}
7286
7287impl DiffTransformSummary {
7288    fn excerpt_len(&self) -> ExcerptOffset {
7289        ExcerptDimension(self.input.len)
7290    }
7291}
7292
7293impl sum_tree::ContextLessSummary for DiffTransformSummary {
7294    fn zero() -> Self {
7295        DiffTransformSummary {
7296            input: MBTextSummary::default(),
7297            output: MBTextSummary::default(),
7298        }
7299    }
7300
7301    fn add_summary(&mut self, other: &Self) {
7302        self.input += other.input;
7303        self.output += other.output;
7304    }
7305}
7306
7307impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7308    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7309        PathKey::min()
7310    }
7311
7312    fn add_summary(
7313        &mut self,
7314        summary: &'_ ExcerptSummary,
7315        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7316    ) {
7317        *self = summary.path_key.clone();
7318    }
7319}
7320
7321impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7322    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7323        MultiBufferOffset::ZERO
7324    }
7325
7326    fn add_summary(
7327        &mut self,
7328        summary: &'_ ExcerptSummary,
7329        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7330    ) {
7331        self += summary.text.len
7332    }
7333}
7334
7335impl sum_tree::ContextLessSummary for ExcerptSummary {
7336    fn zero() -> Self {
7337        Self::min()
7338    }
7339
7340    fn add_summary(&mut self, summary: &Self) {
7341        debug_assert!(
7342            summary.path_key >= self.path_key,
7343            "Path keys must be in ascending order: {:?} > {:?}",
7344            summary.path_key,
7345            self.path_key
7346        );
7347
7348        self.path_key = summary.path_key.clone();
7349        self.max_anchor = summary.max_anchor;
7350        self.text += summary.text;
7351        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7352        self.count += summary.count;
7353    }
7354}
7355
7356impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7357    fn cmp(
7358        &self,
7359        cursor_location: &ExcerptSummary,
7360        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7361    ) -> cmp::Ordering {
7362        match self {
7363            AnchorSeekTarget::Min => Ordering::Less,
7364            AnchorSeekTarget::Max => Ordering::Greater,
7365            AnchorSeekTarget::Excerpt {
7366                path_key,
7367                anchor,
7368                snapshot,
7369            } => {
7370                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7371                if path_comparison.is_ne() {
7372                    path_comparison
7373                } else if let Some(snapshot) = snapshot {
7374                    snapshot
7375                        .remote_id()
7376                        .cmp(&cursor_location.buffer_id)
7377                        .then_with(|| {
7378                            anchor
7379                                .text_anchor()
7380                                .cmp(&cursor_location.max_anchor, snapshot)
7381                        })
7382                } else {
7383                    // shouldn't happen because we expect this buffer not to have any excerpts
7384                    // (otherwise snapshot would have been Some)
7385                    Ordering::Equal
7386                }
7387            }
7388        }
7389    }
7390}
7391
7392impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7393    fn cmp(
7394        &self,
7395        cursor_location: &ExcerptSummary,
7396        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7397    ) -> cmp::Ordering {
7398        todo!()
7399    }
7400}
7401
7402impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7403where
7404    MBD: MultiBufferDimension + Default,
7405{
7406    fn zero(_: ()) -> Self {
7407        ExcerptDimension(MBD::default())
7408    }
7409
7410    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7411        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7412    }
7413}
7414
7415#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7416struct OutputDimension<T>(T);
7417
7418impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7419    fn eq(&self, other: &T) -> bool {
7420        self.0 == *other
7421    }
7422}
7423
7424impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7425    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7426        self.0.partial_cmp(other)
7427    }
7428}
7429
7430impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7431where
7432    T: ops::Sub<U, Output = R>,
7433{
7434    type Output = R;
7435
7436    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7437        self.0 - other.0
7438    }
7439}
7440
7441impl<R, T, U> ops::Add<U> for OutputDimension<T>
7442where
7443    T: ops::Add<U, Output = R>,
7444{
7445    type Output = OutputDimension<R>;
7446
7447    fn add(self, other: U) -> Self::Output {
7448        OutputDimension(self.0 + other)
7449    }
7450}
7451
7452impl<T, U> AddAssign<U> for OutputDimension<T>
7453where
7454    T: AddAssign<U>,
7455{
7456    fn add_assign(&mut self, other: U) {
7457        self.0 += other;
7458    }
7459}
7460
7461impl<T, U> SubAssign<U> for OutputDimension<T>
7462where
7463    T: SubAssign<U>,
7464{
7465    fn sub_assign(&mut self, other: U) {
7466        self.0 -= other;
7467    }
7468}
7469
7470#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7471struct ExcerptDimension<T>(T);
7472
7473impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7474    fn eq(&self, other: &T) -> bool {
7475        self.0 == *other
7476    }
7477}
7478
7479impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7480    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7481        self.0.partial_cmp(other)
7482    }
7483}
7484
7485impl ExcerptOffset {
7486    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7487        self.0.saturating_sub(other.0)
7488    }
7489}
7490
7491impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7492where
7493    T: ops::Sub<U, Output = R>,
7494{
7495    type Output = R;
7496
7497    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7498        self.0 - other.0
7499    }
7500}
7501
7502impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7503where
7504    T: ops::Add<U, Output = R>,
7505{
7506    type Output = ExcerptDimension<R>;
7507
7508    fn add(self, other: U) -> Self::Output {
7509        ExcerptDimension(self.0 + other)
7510    }
7511}
7512
7513impl<T, U> AddAssign<U> for ExcerptDimension<T>
7514where
7515    T: AddAssign<U>,
7516{
7517    fn add_assign(&mut self, other: U) {
7518        self.0 += other;
7519    }
7520}
7521
7522impl<T, U> SubAssign<U> for ExcerptDimension<T>
7523where
7524    T: SubAssign<U>,
7525{
7526    fn sub_assign(&mut self, other: U) {
7527        self.0 -= other;
7528    }
7529}
7530
7531impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7532    fn zero(_: ()) -> Self {
7533        MultiBufferOffset::ZERO
7534    }
7535
7536    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7537        *self += summary.output.len;
7538    }
7539}
7540
7541impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7542    for ExcerptDimension<MBD>
7543where
7544    MBD: MultiBufferDimension + Ord,
7545{
7546    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7547        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7548    }
7549}
7550
7551impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7552    for ExcerptDimension<MBD>
7553where
7554    MBD: MultiBufferDimension + Ord,
7555{
7556    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7557        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7558    }
7559}
7560
7561impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7562    for ExcerptDimension<MBD>
7563{
7564    fn zero(_: ()) -> Self {
7565        ExcerptDimension(MBD::default())
7566    }
7567
7568    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7569        self.0.add_mb_text_summary(&summary.input)
7570    }
7571}
7572
7573impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7574    for OutputDimension<MBD>
7575where
7576    MBD: MultiBufferDimension + Ord,
7577{
7578    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7579        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7580    }
7581}
7582
7583impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7584    for OutputDimension<MBD>
7585{
7586    fn zero(_: ()) -> Self {
7587        OutputDimension(MBD::default())
7588    }
7589
7590    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7591        self.0.add_mb_text_summary(&summary.output)
7592    }
7593}
7594
7595impl MultiBufferRows<'_> {
7596    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7597        self.point = Point::new(row, 0);
7598        self.cursor.seek(&self.point);
7599    }
7600}
7601
7602impl Iterator for MultiBufferRows<'_> {
7603    type Item = RowInfo;
7604
7605    fn next(&mut self) -> Option<Self::Item> {
7606        if self.is_empty && self.point.row == 0 {
7607            self.point += Point::new(1, 0);
7608            return Some(RowInfo {
7609                buffer_id: None,
7610                buffer_row: Some(0),
7611                multibuffer_row: Some(MultiBufferRow(0)),
7612                diff_status: None,
7613                expand_info: None,
7614                wrapped_buffer_row: None,
7615            });
7616        }
7617
7618        let mut region = self.cursor.region()?.clone();
7619        while self.point >= region.range.end {
7620            self.cursor.next();
7621            if let Some(next_region) = self.cursor.region() {
7622                region = next_region.clone();
7623            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7624                let multibuffer_row = MultiBufferRow(self.point.row);
7625                let last_excerpt = self
7626                    .cursor
7627                    .excerpts
7628                    .item()
7629                    .or(self.cursor.excerpts.prev_item())?;
7630                let last_row = last_excerpt
7631                    .range
7632                    .context
7633                    .end
7634                    .to_point(&last_excerpt.buffer)
7635                    .row;
7636
7637                let first_row = last_excerpt
7638                    .range
7639                    .context
7640                    .start
7641                    .to_point(&last_excerpt.buffer)
7642                    .row;
7643
7644                let expand_info = if self.is_singleton {
7645                    None
7646                } else {
7647                    let needs_expand_up = first_row == last_row
7648                        && last_row > 0
7649                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7650                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7651
7652                    if needs_expand_up && needs_expand_down {
7653                        Some(ExpandExcerptDirection::UpAndDown)
7654                    } else if needs_expand_up {
7655                        Some(ExpandExcerptDirection::Up)
7656                    } else if needs_expand_down {
7657                        Some(ExpandExcerptDirection::Down)
7658                    } else {
7659                        None
7660                    }
7661                    .map(|direction| ExpandInfo {
7662                        direction,
7663                        excerpt_id: last_excerpt.id,
7664                    })
7665                };
7666                self.point += Point::new(1, 0);
7667                return Some(RowInfo {
7668                    buffer_id: Some(last_excerpt.buffer_id),
7669                    buffer_row: Some(last_row),
7670                    multibuffer_row: Some(multibuffer_row),
7671                    diff_status: None,
7672                    wrapped_buffer_row: None,
7673                    expand_info,
7674                });
7675            } else {
7676                return None;
7677            };
7678        }
7679
7680        let overshoot = self.point - region.range.start;
7681        let buffer_point = region.buffer_range.start + overshoot;
7682        let expand_info = if self.is_singleton {
7683            None
7684        } else {
7685            let needs_expand_up = self.point.row == region.range.start.row
7686                && self.cursor.is_at_start_of_excerpt()
7687                && buffer_point.row > 0;
7688            let needs_expand_down = (region.excerpt.has_trailing_newline
7689                && self.point.row + 1 == region.range.end.row
7690                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7691                && self.cursor.is_at_end_of_excerpt()
7692                && buffer_point.row < region.buffer.max_point().row;
7693
7694            if needs_expand_up && needs_expand_down {
7695                Some(ExpandExcerptDirection::UpAndDown)
7696            } else if needs_expand_up {
7697                Some(ExpandExcerptDirection::Up)
7698            } else if needs_expand_down {
7699                Some(ExpandExcerptDirection::Down)
7700            } else {
7701                None
7702            }
7703            .map(|direction| ExpandInfo {
7704                direction,
7705                excerpt_id: region.excerpt.id,
7706            })
7707        };
7708
7709        let result = Some(RowInfo {
7710            buffer_id: Some(region.buffer.remote_id()),
7711            buffer_row: Some(buffer_point.row),
7712            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7713            diff_status: region
7714                .diff_hunk_status
7715                .filter(|_| self.point < region.range.end),
7716            expand_info,
7717            wrapped_buffer_row: None,
7718        });
7719        self.point += Point::new(1, 0);
7720        result
7721    }
7722}
7723
7724impl<'a> MultiBufferChunks<'a> {
7725    pub fn offset(&self) -> MultiBufferOffset {
7726        self.range.start
7727    }
7728
7729    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7730        self.diff_transforms.seek(&range.end, Bias::Right);
7731        let mut excerpt_end = self.diff_transforms.start().1;
7732        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7733            let overshoot = range.end - self.diff_transforms.start().0;
7734            excerpt_end += overshoot;
7735        }
7736
7737        self.diff_transforms.seek(&range.start, Bias::Right);
7738        let mut excerpt_start = self.diff_transforms.start().1;
7739        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7740            let overshoot = range.start - self.diff_transforms.start().0;
7741            excerpt_start += overshoot;
7742        }
7743
7744        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7745        self.buffer_chunk.take();
7746        self.range = range;
7747    }
7748
7749    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7750        self.excerpt_offset_range = new_range.clone();
7751        self.excerpts.seek(&new_range.start, Bias::Right);
7752        if let Some(excerpt) = self.excerpts.item() {
7753            let excerpt_start = *self.excerpts.start();
7754            if let Some(excerpt_chunks) = self
7755                .excerpt_chunks
7756                .as_mut()
7757                .filter(|chunks| excerpt.end_anchor() == chunks.end)
7758            {
7759                excerpt.seek_chunks(
7760                    excerpt_chunks,
7761                    (self.excerpt_offset_range.start - excerpt_start)
7762                        ..(self.excerpt_offset_range.end - excerpt_start),
7763                );
7764            } else {
7765                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7766                    (self.excerpt_offset_range.start - excerpt_start)
7767                        ..(self.excerpt_offset_range.end - excerpt_start),
7768                    self.language_aware,
7769                ));
7770            }
7771        } else {
7772            self.excerpt_chunks = None;
7773        }
7774    }
7775
7776    #[ztracing::instrument(skip_all)]
7777    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7778        loop {
7779            if self.excerpt_offset_range.is_empty() {
7780                return None;
7781            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7782                self.excerpt_offset_range.start += chunk.text.len();
7783                return Some(chunk);
7784            } else {
7785                self.excerpts.next();
7786                let excerpt = self.excerpts.item()?;
7787                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7788                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7789                    self.language_aware,
7790                ));
7791            }
7792        }
7793    }
7794}
7795
7796impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7797    type Item = &'a str;
7798
7799    fn next(&mut self) -> Option<Self::Item> {
7800        let mut region = self.cursor.region()?;
7801        if self.offset == region.range.start {
7802            self.cursor.prev();
7803            region = self.cursor.region()?;
7804            let start_overshoot = self.start.saturating_sub(region.range.start);
7805            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7806                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7807            ));
7808        }
7809
7810        if self.offset == region.range.end && region.has_trailing_newline {
7811            self.offset -= 1;
7812            Some("\n")
7813        } else {
7814            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7815            self.offset -= chunk.len();
7816            Some(chunk)
7817        }
7818    }
7819}
7820
7821impl<'a> Iterator for MultiBufferChunks<'a> {
7822    type Item = Chunk<'a>;
7823
7824    #[ztracing::instrument(skip_all)]
7825    fn next(&mut self) -> Option<Chunk<'a>> {
7826        if self.range.start >= self.range.end {
7827            return None;
7828        }
7829        if self.range.start == self.diff_transforms.end().0 {
7830            self.diff_transforms.next();
7831        }
7832
7833        let diff_transform_start = self.diff_transforms.start().0;
7834        let diff_transform_end = self.diff_transforms.end().0;
7835        debug_assert!(
7836            self.range.start < diff_transform_end,
7837            "{:?} < {:?} of ({1:?}..{2:?})",
7838            self.range.start,
7839            diff_transform_end,
7840            diff_transform_start
7841        );
7842
7843        let diff_transform = self.diff_transforms.item()?;
7844        match diff_transform {
7845            DiffTransform::BufferContent { .. } => {
7846                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7847                    chunk
7848                } else {
7849                    let chunk = self.next_excerpt_chunk().unwrap();
7850                    self.buffer_chunk.insert(chunk)
7851                };
7852
7853                let chunk_end = self.range.start + chunk.text.len();
7854                let diff_transform_end = diff_transform_end.min(self.range.end);
7855
7856                if diff_transform_end < chunk_end {
7857                    let split_idx = diff_transform_end - self.range.start;
7858                    let (before, after) = chunk.text.split_at(split_idx);
7859                    self.range.start = diff_transform_end;
7860                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7861                    let chars = chunk.chars & mask;
7862                    let tabs = chunk.tabs & mask;
7863                    let newlines = chunk.newlines & mask;
7864
7865                    chunk.text = after;
7866                    chunk.chars = chunk.chars >> split_idx;
7867                    chunk.tabs = chunk.tabs >> split_idx;
7868                    chunk.newlines = chunk.newlines >> split_idx;
7869
7870                    Some(Chunk {
7871                        text: before,
7872                        chars,
7873                        tabs,
7874                        newlines,
7875                        ..chunk.clone()
7876                    })
7877                } else {
7878                    self.range.start = chunk_end;
7879                    self.buffer_chunk.take()
7880                }
7881            }
7882            DiffTransform::DeletedHunk {
7883                buffer_id,
7884                base_text_byte_range,
7885                has_trailing_newline,
7886                ..
7887            } => {
7888                let base_text_start =
7889                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7890                let base_text_end =
7891                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7892                let base_text_end = base_text_end.min(base_text_byte_range.end);
7893
7894                let mut chunks = if let Some((_, mut chunks)) = self
7895                    .diff_base_chunks
7896                    .take()
7897                    .filter(|(id, _)| id == buffer_id)
7898                {
7899                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7900                    {
7901                        chunks.seek(base_text_start..base_text_end);
7902                    }
7903                    chunks
7904                } else {
7905                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7906                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7907                };
7908
7909                let chunk = if let Some(chunk) = chunks.next() {
7910                    self.range.start += chunk.text.len();
7911                    self.diff_base_chunks = Some((*buffer_id, chunks));
7912                    chunk
7913                } else {
7914                    debug_assert!(has_trailing_newline);
7915                    self.range.start += "\n".len();
7916                    Chunk {
7917                        text: "\n",
7918                        chars: 1u128,
7919                        newlines: 1u128,
7920                        ..Default::default()
7921                    }
7922                };
7923                Some(chunk)
7924            }
7925        }
7926    }
7927}
7928
7929impl MultiBufferBytes<'_> {
7930    fn consume(&mut self, len: usize) {
7931        self.range.start += len;
7932        self.chunk = &self.chunk[len..];
7933
7934        if !self.range.is_empty() && self.chunk.is_empty() {
7935            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7936                self.chunk = chunk;
7937            } else if self.has_trailing_newline {
7938                self.has_trailing_newline = false;
7939                self.chunk = b"\n";
7940            } else {
7941                self.cursor.next();
7942                if let Some(region) = self.cursor.region() {
7943                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7944                        region.buffer_range.start
7945                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7946                                .min(region.buffer_range.end),
7947                    );
7948                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7949                    self.excerpt_bytes = Some(excerpt_bytes);
7950                    self.has_trailing_newline =
7951                        region.has_trailing_newline && self.range.end >= region.range.end;
7952                    if self.chunk.is_empty() && self.has_trailing_newline {
7953                        self.has_trailing_newline = false;
7954                        self.chunk = b"\n";
7955                    }
7956                }
7957            }
7958        }
7959    }
7960}
7961
7962impl<'a> Iterator for MultiBufferBytes<'a> {
7963    type Item = &'a [u8];
7964
7965    fn next(&mut self) -> Option<Self::Item> {
7966        let chunk = self.chunk;
7967        if chunk.is_empty() {
7968            None
7969        } else {
7970            self.consume(chunk.len());
7971            Some(chunk)
7972        }
7973    }
7974}
7975
7976impl io::Read for MultiBufferBytes<'_> {
7977    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7978        let len = cmp::min(buf.len(), self.chunk.len());
7979        buf[..len].copy_from_slice(&self.chunk[..len]);
7980        if len > 0 {
7981            self.consume(len);
7982        }
7983        Ok(len)
7984    }
7985}
7986
7987impl io::Read for ReversedMultiBufferBytes<'_> {
7988    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7989        let len = cmp::min(buf.len(), self.chunk.len());
7990        buf[..len].copy_from_slice(&self.chunk[..len]);
7991        buf[..len].reverse();
7992        if len > 0 {
7993            self.range.end -= len;
7994            self.chunk = &self.chunk[..self.chunk.len() - len];
7995            if !self.range.is_empty()
7996                && self.chunk.is_empty()
7997                && let Some(chunk) = self.chunks.next()
7998            {
7999                self.chunk = chunk.as_bytes();
8000            }
8001        }
8002        Ok(len)
8003    }
8004}
8005
8006impl<'a> Iterator for ExcerptChunks<'a> {
8007    type Item = Chunk<'a>;
8008
8009    fn next(&mut self) -> Option<Self::Item> {
8010        if let Some(chunk) = self.content_chunks.next() {
8011            return Some(chunk);
8012        }
8013
8014        if self.has_footer {
8015            let text = "\n";
8016            let chars = 0b1;
8017            let newlines = 0b1;
8018            self.has_footer = false;
8019            return Some(Chunk {
8020                text,
8021                chars,
8022                newlines,
8023                ..Default::default()
8024            });
8025        }
8026
8027        None
8028    }
8029}
8030
8031impl ToOffset for Point {
8032    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8033        snapshot.point_to_offset(*self)
8034    }
8035    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8036        snapshot.point_to_offset_utf16(*self)
8037    }
8038}
8039
8040impl ToOffset for MultiBufferOffset {
8041    #[track_caller]
8042    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8043        assert!(
8044            *self <= snapshot.len(),
8045            "offset {} is greater than the snapshot.len() {}",
8046            self.0,
8047            snapshot.len().0,
8048        );
8049        *self
8050    }
8051    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8052        snapshot.offset_to_offset_utf16(*self)
8053    }
8054}
8055
8056impl ToOffset for MultiBufferOffsetUtf16 {
8057    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8058        snapshot.offset_utf16_to_offset(*self)
8059    }
8060
8061    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8062        *self
8063    }
8064}
8065
8066impl ToOffset for PointUtf16 {
8067    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8068        snapshot.point_utf16_to_offset(*self)
8069    }
8070    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8071        snapshot.point_utf16_to_offset_utf16(*self)
8072    }
8073}
8074
8075impl ToPoint for MultiBufferOffset {
8076    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8077        snapshot.offset_to_point(*self)
8078    }
8079    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8080        snapshot.offset_to_point_utf16(*self)
8081    }
8082}
8083
8084impl ToPoint for Point {
8085    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8086        *self
8087    }
8088    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8089        snapshot.point_to_point_utf16(*self)
8090    }
8091}
8092
8093impl ToPoint for PointUtf16 {
8094    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8095        snapshot.point_utf16_to_point(*self)
8096    }
8097    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8098        *self
8099    }
8100}
8101
8102#[cfg(debug_assertions)]
8103pub mod debug {
8104    use super::*;
8105
8106    pub trait ToMultiBufferDebugRanges {
8107        fn to_multi_buffer_debug_ranges(
8108            &self,
8109            snapshot: &MultiBufferSnapshot,
8110        ) -> Vec<Range<MultiBufferOffset>>;
8111    }
8112
8113    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8114        fn to_multi_buffer_debug_ranges(
8115            &self,
8116            snapshot: &MultiBufferSnapshot,
8117        ) -> Vec<Range<MultiBufferOffset>> {
8118            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8119        }
8120    }
8121
8122    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8123        fn to_multi_buffer_debug_ranges(
8124            &self,
8125            snapshot: &MultiBufferSnapshot,
8126        ) -> Vec<Range<MultiBufferOffset>> {
8127            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8128                .to_multi_buffer_debug_ranges(snapshot)
8129        }
8130    }
8131
8132    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8133        fn to_multi_buffer_debug_ranges(
8134            &self,
8135            snapshot: &MultiBufferSnapshot,
8136        ) -> Vec<Range<MultiBufferOffset>> {
8137            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8138        }
8139    }
8140
8141    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8142        fn to_multi_buffer_debug_ranges(
8143            &self,
8144            snapshot: &MultiBufferSnapshot,
8145        ) -> Vec<Range<MultiBufferOffset>> {
8146            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8147        }
8148    }
8149
8150    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8151        fn to_multi_buffer_debug_ranges(
8152            &self,
8153            snapshot: &MultiBufferSnapshot,
8154        ) -> Vec<Range<MultiBufferOffset>> {
8155            self.iter()
8156                .map(|item| {
8157                    let offset = item.to_offset(snapshot);
8158                    offset..offset
8159                })
8160                .collect()
8161        }
8162    }
8163
8164    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8165        fn to_multi_buffer_debug_ranges(
8166            &self,
8167            snapshot: &MultiBufferSnapshot,
8168        ) -> Vec<Range<MultiBufferOffset>> {
8169            self.iter()
8170                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8171                .collect()
8172        }
8173    }
8174}