multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use crate::anchor::ExcerptAnchor;
   8
   9use self::transaction::History;
  10
  11pub use anchor::{Anchor, AnchorRangeExt};
  12
  13use anchor::AnchorSeekTarget;
  14use anyhow::{Result, anyhow};
  15use buffer_diff::{
  16    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  17    DiffHunkStatus, DiffHunkStatusKind,
  18};
  19use clock::ReplicaId;
  20use collections::{BTreeMap, Bound, HashMap, HashSet};
  21use gpui::{App, Context, Entity, EventEmitter};
  22use itertools::Itertools;
  23use language::{
  24    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  25    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  26    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  27    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  28    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  29    language_settings::{LanguageSettings, language_settings},
  30};
  31
  32#[cfg(any(test, feature = "test-support"))]
  33use gpui::AppContext as _;
  34
  35use rope::DimensionPair;
  36use smallvec::SmallVec;
  37use smol::future::yield_now;
  38use std::{
  39    any::type_name,
  40    borrow::Cow,
  41    cell::{Cell, OnceCell, Ref, RefCell},
  42    cmp::{self, Ordering},
  43    fmt,
  44    future::Future,
  45    io,
  46    iter::{self, FromIterator},
  47    mem,
  48    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  49    rc::Rc,
  50    str,
  51    sync::{Arc, OnceLock},
  52    time::Duration,
  53};
  54use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  55use text::{
  56    BufferId, Edit, LineIndent, TextSummary,
  57    subscription::{Subscription, Topic},
  58};
  59use theme::SyntaxTheme;
  60use ztracing::instrument;
  61
  62pub use self::path_key::PathKey;
  63
  64pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  65
  66pub fn excerpt_context_lines(cx: &App) -> u32 {
  67    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  68}
  69
  70/// One or more [`Buffers`](Buffer) being edited in a single view.
  71///
  72/// See <https://zed.dev/features#multi-buffers>
  73pub struct MultiBuffer {
  74    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  75    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  76    snapshot: RefCell<MultiBufferSnapshot>,
  77    /// Contains the state of the buffers being edited
  78    buffers: BTreeMap<BufferId, BufferState>,
  79    /// Mapping from buffer IDs to their diff states
  80    diffs: HashMap<BufferId, DiffState>,
  81    subscriptions: Topic<MultiBufferOffset>,
  82    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  83    singleton: bool,
  84    /// The history of the multi-buffer.
  85    history: History,
  86    /// The explicit title of the multi-buffer.
  87    /// If `None`, it will be derived from the underlying path or content.
  88    title: Option<String>,
  89    /// The writing capability of the multi-buffer.
  90    capability: Capability,
  91    buffer_changed_since_sync: Rc<Cell<bool>>,
  92}
  93
  94#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
  95pub struct PathKeyIndex(u64);
  96
  97#[derive(Clone, Debug, PartialEq, Eq, Hash)]
  98pub struct ExcerptInfo {
  99    path_key_index: PathKeyIndex,
 100    buffer_id: BufferId,
 101    range: ExcerptRange<text::Anchor>,
 102}
 103
 104impl ExcerptInfo {
 105    pub fn end_anchor(&self) -> Anchor {
 106        Anchor::in_buffer(self.path_key_index, self.range.context.end)
 107    }
 108}
 109
 110#[derive(Clone, Debug, PartialEq, Eq)]
 111pub enum Event {
 112    BufferUpdated {
 113        buffer: Entity<Buffer>,
 114        path_key: PathKey,
 115        ranges: Vec<ExcerptRange<text::Anchor>>,
 116    },
 117    BuffersRemoved {
 118        removed_buffer_ids: Vec<BufferId>,
 119    },
 120    BuffersEdited {
 121        buffer_ids: Vec<BufferId>,
 122    },
 123    DiffHunksToggled,
 124    Edited {
 125        edited_buffer: Option<Entity<Buffer>>,
 126    },
 127    TransactionUndone {
 128        transaction_id: TransactionId,
 129    },
 130    Reloaded,
 131    LanguageChanged(BufferId, bool),
 132    Reparsed(BufferId),
 133    Saved,
 134    FileHandleChanged,
 135    DirtyChanged,
 136    DiagnosticsUpdated,
 137    BufferDiffChanged,
 138}
 139
 140/// A diff hunk, representing a range of consequent lines in a multibuffer.
 141#[derive(Debug, Clone, PartialEq, Eq)]
 142pub struct MultiBufferDiffHunk {
 143    /// The row range in the multibuffer where this diff hunk appears.
 144    pub row_range: Range<MultiBufferRow>,
 145    path_key_index: PathKeyIndex,
 146    /// The buffer ID that this hunk belongs to.
 147    pub buffer_id: BufferId,
 148    /// The range of the underlying buffer that this hunk corresponds to.
 149    pub buffer_range: Range<text::Anchor>,
 150    /// The range within the buffer's diff base that this hunk corresponds to.
 151    pub diff_base_byte_range: Range<BufferOffset>,
 152    /// The status of this hunk (added/modified/deleted and secondary status).
 153    pub status: DiffHunkStatus,
 154    /// The word diffs for this hunk.
 155    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 156}
 157
 158impl MultiBufferDiffHunk {
 159    pub fn status(&self) -> DiffHunkStatus {
 160        self.status
 161    }
 162
 163    pub fn is_created_file(&self) -> bool {
 164        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 165            && self.buffer_range.start.is_min()
 166            && self.buffer_range.end.is_max()
 167    }
 168
 169    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 170        let start = Anchor::in_buffer(self.path_key_index, self.buffer_range.start);
 171        let end = Anchor::in_buffer(self.path_key_index, self.buffer_range.end);
 172        start..end
 173    }
 174}
 175
 176pub type MultiBufferPoint = Point;
 177/// ExcerptOffset is offset into the non-deleted text of the multibuffer
 178type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 179/// ExcerptOffset is based on the non-deleted text of the multibuffer
 180type ExcerptPoint = ExcerptDimension<Point>;
 181
 182#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 183#[serde(transparent)]
 184pub struct MultiBufferRow(pub u32);
 185
 186impl MultiBufferRow {
 187    pub const MIN: Self = Self(0);
 188    pub const MAX: Self = Self(u32::MAX);
 189}
 190
 191impl ops::Add<usize> for MultiBufferRow {
 192    type Output = Self;
 193
 194    fn add(self, rhs: usize) -> Self::Output {
 195        MultiBufferRow(self.0 + rhs as u32)
 196    }
 197}
 198
 199pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 200    type TextDimension: TextDimension;
 201    fn from_summary(summary: &MBTextSummary) -> Self;
 202
 203    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 204
 205    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 206}
 207
 208// todo(lw): MultiBufferPoint
 209impl MultiBufferDimension for Point {
 210    type TextDimension = Point;
 211    fn from_summary(summary: &MBTextSummary) -> Self {
 212        summary.lines
 213    }
 214
 215    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 216        *self += *other;
 217    }
 218
 219    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 220        *self += summary.lines;
 221    }
 222}
 223
 224// todo(lw): MultiBufferPointUtf16
 225impl MultiBufferDimension for PointUtf16 {
 226    type TextDimension = PointUtf16;
 227    fn from_summary(summary: &MBTextSummary) -> Self {
 228        summary.lines_utf16()
 229    }
 230
 231    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 232        *self += *other;
 233    }
 234
 235    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 236        *self += summary.lines_utf16();
 237    }
 238}
 239
 240#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 241pub struct MultiBufferOffset(pub usize);
 242
 243impl fmt::Display for MultiBufferOffset {
 244    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 245        write!(f, "{}", self.0)
 246    }
 247}
 248
 249impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 250    type Sampler = MultiBufferOffsetUniformSampler;
 251}
 252
 253pub struct MultiBufferOffsetUniformSampler {
 254    sampler: rand::distr::uniform::UniformUsize,
 255}
 256
 257impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 258    type X = MultiBufferOffset;
 259
 260    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 261    where
 262        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 263        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 264    {
 265        let low = *low_b.borrow();
 266        let high = *high_b.borrow();
 267        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 268        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 269    }
 270
 271    #[inline] // if the range is constant, this helps LLVM to do the
 272    // calculations at compile-time.
 273    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 274    where
 275        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 276        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 277    {
 278        let low = *low_b.borrow();
 279        let high = *high_b.borrow();
 280        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 281        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 282    }
 283
 284    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 285        MultiBufferOffset(self.sampler.sample(rng))
 286    }
 287}
 288impl MultiBufferDimension for MultiBufferOffset {
 289    type TextDimension = usize;
 290    fn from_summary(summary: &MBTextSummary) -> Self {
 291        summary.len
 292    }
 293
 294    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 295        self.0 += *other;
 296    }
 297
 298    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 299        *self += summary.len;
 300    }
 301}
 302impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 303    type TextDimension = OffsetUtf16;
 304    fn from_summary(summary: &MBTextSummary) -> Self {
 305        MultiBufferOffsetUtf16(summary.len_utf16)
 306    }
 307
 308    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 309        self.0 += *other;
 310    }
 311
 312    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 313        self.0 += summary.len_utf16;
 314    }
 315}
 316
 317#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 318pub struct BufferOffset(pub usize);
 319
 320impl TextDimension for BufferOffset {
 321    fn from_text_summary(summary: &TextSummary) -> Self {
 322        BufferOffset(usize::from_text_summary(summary))
 323    }
 324    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 325        BufferOffset(usize::from_chunk(chunk))
 326    }
 327    fn add_assign(&mut self, other: &Self) {
 328        TextDimension::add_assign(&mut self.0, &other.0);
 329    }
 330}
 331impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 332    fn zero(cx: ()) -> Self {
 333        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 334    }
 335
 336    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 337        usize::add_summary(&mut self.0, summary, cx);
 338    }
 339}
 340
 341impl Sub for BufferOffset {
 342    type Output = usize;
 343
 344    fn sub(self, other: BufferOffset) -> Self::Output {
 345        self.0 - other.0
 346    }
 347}
 348
 349impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 350    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 351        self.0 += other.key;
 352    }
 353}
 354
 355impl language::ToPoint for BufferOffset {
 356    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 357        self.0.to_point(snapshot)
 358    }
 359}
 360
 361impl language::ToPointUtf16 for BufferOffset {
 362    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 363        self.0.to_point_utf16(snapshot)
 364    }
 365}
 366
 367impl language::ToOffset for BufferOffset {
 368    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 369        self.0.to_offset(snapshot)
 370    }
 371}
 372
 373impl language::ToOffsetUtf16 for BufferOffset {
 374    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 375        self.0.to_offset_utf16(snapshot)
 376    }
 377}
 378
 379#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 380pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 381
 382impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 383    type Output = MultiBufferOffsetUtf16;
 384
 385    fn add(self, rhs: usize) -> Self::Output {
 386        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 387    }
 388}
 389
 390impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 391    type Output = Self;
 392
 393    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 394        MultiBufferOffsetUtf16(self.0 + rhs)
 395    }
 396}
 397
 398impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 399    fn add_assign(&mut self, rhs: OffsetUtf16) {
 400        self.0 += rhs;
 401    }
 402}
 403
 404impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 405    fn add_assign(&mut self, rhs: usize) {
 406        self.0.0 += rhs;
 407    }
 408}
 409
 410impl Sub for MultiBufferOffsetUtf16 {
 411    type Output = OffsetUtf16;
 412
 413    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 414        self.0 - other.0
 415    }
 416}
 417
 418impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 419    type Output = MultiBufferOffsetUtf16;
 420
 421    fn sub(self, other: OffsetUtf16) -> Self::Output {
 422        MultiBufferOffsetUtf16(self.0 - other)
 423    }
 424}
 425
 426#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 427pub struct BufferOffsetUtf16(pub OffsetUtf16);
 428
 429impl MultiBufferOffset {
 430    const ZERO: Self = Self(0);
 431    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 432        self.0.saturating_sub(other.0)
 433    }
 434    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 435        MultiBufferOffset(self.0.saturating_sub(other))
 436    }
 437}
 438
 439impl ops::Sub for MultiBufferOffset {
 440    type Output = usize;
 441
 442    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 443        self.0 - other.0
 444    }
 445}
 446
 447impl ops::Sub<usize> for MultiBufferOffset {
 448    type Output = Self;
 449
 450    fn sub(self, other: usize) -> Self::Output {
 451        MultiBufferOffset(self.0 - other)
 452    }
 453}
 454
 455impl ops::SubAssign<usize> for MultiBufferOffset {
 456    fn sub_assign(&mut self, other: usize) {
 457        self.0 -= other;
 458    }
 459}
 460
 461impl ops::Add<usize> for BufferOffset {
 462    type Output = Self;
 463
 464    fn add(self, rhs: usize) -> Self::Output {
 465        BufferOffset(self.0 + rhs)
 466    }
 467}
 468
 469impl ops::AddAssign<usize> for BufferOffset {
 470    fn add_assign(&mut self, other: usize) {
 471        self.0 += other;
 472    }
 473}
 474
 475impl ops::Add<usize> for MultiBufferOffset {
 476    type Output = Self;
 477
 478    fn add(self, rhs: usize) -> Self::Output {
 479        MultiBufferOffset(self.0 + rhs)
 480    }
 481}
 482
 483impl ops::AddAssign<usize> for MultiBufferOffset {
 484    fn add_assign(&mut self, other: usize) {
 485        self.0 += other;
 486    }
 487}
 488
 489impl ops::Add<isize> for MultiBufferOffset {
 490    type Output = Self;
 491
 492    fn add(self, rhs: isize) -> Self::Output {
 493        MultiBufferOffset((self.0 as isize + rhs) as usize)
 494    }
 495}
 496
 497impl ops::Add for MultiBufferOffset {
 498    type Output = Self;
 499
 500    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 501        MultiBufferOffset(self.0 + rhs.0)
 502    }
 503}
 504
 505impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 506    fn add_assign(&mut self, other: MultiBufferOffset) {
 507        self.0 += other.0;
 508    }
 509}
 510
 511pub trait ToOffset: 'static + fmt::Debug {
 512    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 513    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 514}
 515
 516pub trait ToPoint: 'static + fmt::Debug {
 517    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 518    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 519}
 520
 521struct BufferState {
 522    buffer: Entity<Buffer>,
 523    _subscriptions: [gpui::Subscription; 2],
 524}
 525
 526struct DiffState {
 527    diff: Entity<BufferDiff>,
 528    main_buffer: Option<Entity<language::Buffer>>,
 529    _subscription: gpui::Subscription,
 530}
 531
 532impl DiffState {
 533    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 534        DiffStateSnapshot {
 535            diff: self.diff.read(cx).snapshot(cx),
 536            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 537        }
 538    }
 539}
 540
 541#[derive(Clone)]
 542struct DiffStateSnapshot {
 543    diff: BufferDiffSnapshot,
 544    main_buffer: Option<language::BufferSnapshot>,
 545}
 546
 547impl std::ops::Deref for DiffStateSnapshot {
 548    type Target = BufferDiffSnapshot;
 549
 550    fn deref(&self) -> &Self::Target {
 551        &self.diff
 552    }
 553}
 554
 555impl DiffState {
 556    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 557        DiffState {
 558            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 559                BufferDiffEvent::DiffChanged(DiffChanged {
 560                    changed_range,
 561                    base_text_changed_range: _,
 562                    extended_range,
 563                }) => {
 564                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 565                    let range = if use_extended {
 566                        extended_range.clone()
 567                    } else {
 568                        changed_range.clone()
 569                    };
 570                    if let Some(range) = range {
 571                        this.buffer_diff_changed(diff, range, cx)
 572                    }
 573                    cx.emit(Event::BufferDiffChanged);
 574                }
 575                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 576                _ => {}
 577            }),
 578            diff,
 579            main_buffer: None,
 580        }
 581    }
 582
 583    fn new_inverted(
 584        diff: Entity<BufferDiff>,
 585        main_buffer: Entity<language::Buffer>,
 586        cx: &mut Context<MultiBuffer>,
 587    ) -> Self {
 588        let weak_main_buffer = main_buffer.downgrade();
 589        DiffState {
 590            _subscription: cx.subscribe(&diff, {
 591                move |this, diff, event, cx| {
 592                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 593                        return;
 594                    };
 595                    match event {
 596                        BufferDiffEvent::DiffChanged(DiffChanged {
 597                            changed_range: _,
 598                            base_text_changed_range,
 599                            extended_range: _,
 600                        }) => {
 601                            this.inverted_buffer_diff_changed(
 602                                diff,
 603                                main_buffer,
 604                                base_text_changed_range.clone(),
 605                                cx,
 606                            );
 607                            cx.emit(Event::BufferDiffChanged);
 608                        }
 609                        BufferDiffEvent::LanguageChanged => {
 610                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 611                        }
 612                        _ => {}
 613                    }
 614                }
 615            }),
 616            diff,
 617            main_buffer: Some(main_buffer),
 618        }
 619    }
 620}
 621
 622#[derive(Clone)]
 623struct BufferStateSnapshot {
 624    path_key: PathKey,
 625    buffer_snapshot: BufferSnapshot,
 626}
 627
 628/// The contents of a [`MultiBuffer`] at a single point in time.
 629#[derive(Clone, Default)]
 630pub struct MultiBufferSnapshot {
 631    excerpts: SumTree<Excerpt>,
 632    buffers: TreeMap<BufferId, BufferStateSnapshot>,
 633    path_keys_by_index: TreeMap<PathKeyIndex, PathKey>,
 634    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 635    diff_transforms: SumTree<DiffTransform>,
 636    non_text_state_update_count: usize,
 637    edit_count: usize,
 638    is_dirty: bool,
 639    has_deleted_file: bool,
 640    has_conflict: bool,
 641    has_inverted_diff: bool,
 642    singleton: bool,
 643    trailing_excerpt_update_count: usize,
 644    all_diff_hunks_expanded: bool,
 645    show_deleted_hunks: bool,
 646    use_extended_diff_range: bool,
 647    show_headers: bool,
 648}
 649
 650#[derive(Debug, Clone)]
 651enum DiffTransform {
 652    BufferContent {
 653        summary: MBTextSummary,
 654        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 655    },
 656    DeletedHunk {
 657        summary: TextSummary,
 658        buffer_id: BufferId,
 659        hunk_info: DiffTransformHunkInfo,
 660        base_text_byte_range: Range<usize>,
 661        has_trailing_newline: bool,
 662    },
 663}
 664
 665#[derive(Clone, Copy, Debug)]
 666struct DiffTransformHunkInfo {
 667    buffer_id: BufferId,
 668    hunk_start_anchor: text::Anchor,
 669    hunk_secondary_status: DiffHunkSecondaryStatus,
 670    is_logically_deleted: bool,
 671    excerpt_end: ExcerptAnchor,
 672}
 673
 674impl Eq for DiffTransformHunkInfo {}
 675
 676impl PartialEq for DiffTransformHunkInfo {
 677    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 678        self.buffer_id == other.buffer_id && self.hunk_start_anchor == other.hunk_start_anchor
 679    }
 680}
 681
 682impl std::hash::Hash for DiffTransformHunkInfo {
 683    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 684        self.buffer_id.hash(state);
 685        self.hunk_start_anchor.hash(state);
 686    }
 687}
 688
 689#[derive(Clone)]
 690pub struct ExcerptBoundaryInfo {
 691    // todo!() do we need the buffer?
 692    pub buffer: BufferSnapshot,
 693    path_key_index: PathKeyIndex,
 694    pub range: ExcerptRange<text::Anchor>,
 695    pub end_row: MultiBufferRow,
 696}
 697
 698impl std::fmt::Debug for ExcerptBoundaryInfo {
 699    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 700        f.debug_struct(type_name::<Self>())
 701            .field("buffer_id", &self.buffer.remote_id())
 702            .field("path", &self.buffer.file().map(|f| f.path()))
 703            .field("range", &self.range)
 704            .finish()
 705    }
 706}
 707
 708/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 709#[derive(Debug)]
 710pub struct ExcerptBoundary {
 711    pub prev: Option<ExcerptBoundaryInfo>,
 712    pub next: ExcerptBoundaryInfo,
 713    /// The row in the `MultiBuffer` where the boundary is located
 714    pub row: MultiBufferRow,
 715}
 716
 717impl ExcerptBoundary {
 718    pub fn starts_new_buffer(&self) -> bool {
 719        match (self.prev.as_ref(), &self.next) {
 720            (None, _) => true,
 721            (Some(prev), next) => prev.buffer.remote_id() != next.buffer.remote_id(),
 722        }
 723    }
 724}
 725
 726#[derive(Clone, Debug, PartialEq, Eq)]
 727pub struct ExpandInfo {
 728    pub direction: ExpandExcerptDirection,
 729    pub excerpt_range: Range<text::Anchor>,
 730}
 731
 732#[derive(Clone, Debug, Default, PartialEq, Eq)]
 733pub struct RowInfo {
 734    pub buffer_id: Option<BufferId>,
 735    pub buffer_row: Option<u32>,
 736    pub multibuffer_row: Option<MultiBufferRow>,
 737    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 738    pub expand_info: Option<ExpandInfo>,
 739    pub wrapped_buffer_row: Option<u32>,
 740}
 741
 742/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 743#[derive(Clone)]
 744pub(crate) struct Excerpt {
 745    /// The location of the excerpt in the [`MultiBuffer`]
 746    pub(crate) path_key: PathKey,
 747    pub(crate) path_key_index: PathKeyIndex,
 748    pub(crate) buffer_id: BufferId,
 749    /// The range of the buffer to be shown in the excerpt
 750    pub(crate) range: ExcerptRange<text::Anchor>,
 751
 752    /// The last row in the excerpted slice of the buffer
 753    pub(crate) max_buffer_row: BufferRow,
 754    /// A summary of the text in the excerpt
 755    pub(crate) text_summary: TextSummary,
 756    pub(crate) has_trailing_newline: bool,
 757}
 758
 759/// A public view into an `Excerpt` in a [`MultiBuffer`].
 760///
 761/// Contains methods for getting the [`Buffer`] of the excerpt,
 762/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 763#[derive(Clone)]
 764pub struct MultiBufferExcerpt<'a> {
 765    excerpt: &'a Excerpt,
 766    diff_transforms:
 767        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 768    /// The offset in the multibuffer considering diff transforms.
 769    offset: MultiBufferOffset,
 770    /// The offset in the multibuffer without diff transforms.
 771    excerpt_offset: ExcerptOffset,
 772    buffer_offset: BufferOffset,
 773}
 774
 775/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 776/// These ranges are relative to the buffer itself
 777#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 778pub struct ExcerptRange<T> {
 779    /// The full range of text to be shown in the excerpt.
 780    pub context: Range<T>,
 781    /// The primary range of text to be highlighted in the excerpt.
 782    /// In a multi-buffer search, this would be the text that matched the search
 783    pub primary: Range<T>,
 784}
 785
 786impl<T: Clone> ExcerptRange<T> {
 787    pub fn new(context: Range<T>) -> Self {
 788        Self {
 789            context: context.clone(),
 790            primary: context,
 791        }
 792    }
 793}
 794
 795impl ExcerptRange<text::Anchor> {
 796    pub fn contains(&self, t: &text::Anchor, snapshot: &BufferSnapshot) -> bool {
 797        self.context.start.cmp(t, snapshot).is_le() && self.context.end.cmp(t, snapshot).is_ge()
 798    }
 799}
 800
 801#[derive(Clone, Debug)]
 802pub struct ExcerptSummary {
 803    path_key: PathKey,
 804    max_anchor: text::Anchor,
 805    widest_line_number: u32,
 806    text: MBTextSummary,
 807    count: usize,
 808}
 809
 810impl ExcerptSummary {
 811    pub fn min() -> Self {
 812        ExcerptSummary {
 813            path_key: PathKey::min(),
 814            max_anchor: text::Anchor::MIN,
 815            widest_line_number: 0,
 816            text: MBTextSummary::default(),
 817            count: 0,
 818        }
 819    }
 820
 821    pub fn len(&self) -> ExcerptOffset {
 822        ExcerptDimension(self.text.len)
 823    }
 824}
 825
 826#[derive(Debug, Clone)]
 827pub struct DiffTransformSummary {
 828    input: MBTextSummary,
 829    output: MBTextSummary,
 830}
 831
 832/// Summary of a string of text.
 833#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 834pub struct MBTextSummary {
 835    /// Length in bytes.
 836    pub len: MultiBufferOffset,
 837    /// Length in UTF-8.
 838    pub chars: usize,
 839    /// Length in UTF-16 code units
 840    pub len_utf16: OffsetUtf16,
 841    /// A point representing the number of lines and the length of the last line.
 842    ///
 843    /// In other words, it marks the point after the last byte in the text, (if
 844    /// EOF was a character, this would be its position).
 845    pub lines: Point,
 846    /// How many `char`s are in the first line
 847    pub first_line_chars: u32,
 848    /// How many `char`s are in the last line
 849    pub last_line_chars: u32,
 850    /// How many UTF-16 code units are in the last line
 851    pub last_line_len_utf16: u32,
 852    /// The row idx of the longest row
 853    pub longest_row: u32,
 854    /// How many `char`s are in the longest row
 855    pub longest_row_chars: u32,
 856}
 857
 858impl From<TextSummary> for MBTextSummary {
 859    fn from(summary: TextSummary) -> Self {
 860        MBTextSummary {
 861            len: MultiBufferOffset(summary.len),
 862            chars: summary.chars,
 863            len_utf16: summary.len_utf16,
 864            lines: summary.lines,
 865            first_line_chars: summary.first_line_chars,
 866            last_line_chars: summary.last_line_chars,
 867            last_line_len_utf16: summary.last_line_len_utf16,
 868            longest_row: summary.longest_row,
 869            longest_row_chars: summary.longest_row_chars,
 870        }
 871    }
 872}
 873
 874impl From<MBTextSummary> for TextSummary {
 875    fn from(summary: MBTextSummary) -> Self {
 876        TextSummary {
 877            len: summary.len.0,
 878            chars: summary.chars,
 879            len_utf16: summary.len_utf16,
 880            lines: summary.lines,
 881            first_line_chars: summary.first_line_chars,
 882            last_line_chars: summary.last_line_chars,
 883            last_line_len_utf16: summary.last_line_len_utf16,
 884            longest_row: summary.longest_row,
 885            longest_row_chars: summary.longest_row_chars,
 886        }
 887    }
 888}
 889
 890impl From<&str> for MBTextSummary {
 891    fn from(text: &str) -> Self {
 892        MBTextSummary::from(TextSummary::from(text))
 893    }
 894}
 895
 896impl MultiBufferDimension for MBTextSummary {
 897    type TextDimension = TextSummary;
 898
 899    fn from_summary(summary: &MBTextSummary) -> Self {
 900        *summary
 901    }
 902
 903    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 904        *self += *summary;
 905    }
 906
 907    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 908        *self += *summary;
 909    }
 910}
 911
 912impl AddAssign for MBTextSummary {
 913    fn add_assign(&mut self, other: MBTextSummary) {
 914        let joined_chars = self.last_line_chars + other.first_line_chars;
 915        if joined_chars > self.longest_row_chars {
 916            self.longest_row = self.lines.row;
 917            self.longest_row_chars = joined_chars;
 918        }
 919        if other.longest_row_chars > self.longest_row_chars {
 920            self.longest_row = self.lines.row + other.longest_row;
 921            self.longest_row_chars = other.longest_row_chars;
 922        }
 923
 924        if self.lines.row == 0 {
 925            self.first_line_chars += other.first_line_chars;
 926        }
 927
 928        if other.lines.row == 0 {
 929            self.last_line_chars += other.first_line_chars;
 930            self.last_line_len_utf16 += other.last_line_len_utf16;
 931        } else {
 932            self.last_line_chars = other.last_line_chars;
 933            self.last_line_len_utf16 = other.last_line_len_utf16;
 934        }
 935
 936        self.chars += other.chars;
 937        self.len += other.len;
 938        self.len_utf16 += other.len_utf16;
 939        self.lines += other.lines;
 940    }
 941}
 942
 943impl AddAssign<TextSummary> for MBTextSummary {
 944    fn add_assign(&mut self, other: TextSummary) {
 945        *self += MBTextSummary::from(other);
 946    }
 947}
 948
 949impl MBTextSummary {
 950    pub fn lines_utf16(&self) -> PointUtf16 {
 951        PointUtf16 {
 952            row: self.lines.row,
 953            column: self.last_line_len_utf16,
 954        }
 955    }
 956}
 957
 958impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 959where
 960    K: MultiBufferDimension,
 961    V: MultiBufferDimension,
 962{
 963    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 964
 965    fn from_summary(summary: &MBTextSummary) -> Self {
 966        Self {
 967            key: K::from_summary(summary),
 968            value: Some(V::from_summary(summary)),
 969        }
 970    }
 971
 972    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 973        self.key.add_text_dim(&summary.key);
 974        if let Some(value) = &mut self.value {
 975            if let Some(other_value) = summary.value.as_ref() {
 976                value.add_text_dim(other_value);
 977            }
 978        }
 979    }
 980
 981    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 982        self.key.add_mb_text_summary(summary);
 983        if let Some(value) = &mut self.value {
 984            value.add_mb_text_summary(summary);
 985        }
 986    }
 987}
 988
 989#[derive(Clone)]
 990pub struct MultiBufferRows<'a> {
 991    point: Point,
 992    is_empty: bool,
 993    is_singleton: bool,
 994    cursor: MultiBufferCursor<'a, Point, Point>,
 995}
 996
 997pub struct MultiBufferChunks<'a> {
 998    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 999    diff_transforms:
1000        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
1001    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
1002    buffer_chunk: Option<Chunk<'a>>,
1003    range: Range<MultiBufferOffset>,
1004    excerpt_offset_range: Range<ExcerptOffset>,
1005    excerpt_chunks: Option<ExcerptChunks<'a>>,
1006    language_aware: bool,
1007    snapshot: &'a MultiBufferSnapshot,
1008}
1009
1010pub struct ReversedMultiBufferChunks<'a> {
1011    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1012    current_chunks: Option<rope::Chunks<'a>>,
1013    start: MultiBufferOffset,
1014    offset: MultiBufferOffset,
1015}
1016
1017pub struct MultiBufferBytes<'a> {
1018    range: Range<MultiBufferOffset>,
1019    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1020    excerpt_bytes: Option<text::Bytes<'a>>,
1021    has_trailing_newline: bool,
1022    chunk: &'a [u8],
1023}
1024
1025pub struct ReversedMultiBufferBytes<'a> {
1026    range: Range<MultiBufferOffset>,
1027    chunks: ReversedMultiBufferChunks<'a>,
1028    chunk: &'a [u8],
1029}
1030
1031#[derive(Clone)]
1032struct DiffTransforms<MBD> {
1033    output_dimension: OutputDimension<MBD>,
1034    excerpt_dimension: ExcerptDimension<MBD>,
1035}
1036
1037impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1038    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1039        Self {
1040            output_dimension: OutputDimension::zero(cx),
1041            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1042                cx,
1043            ),
1044        }
1045    }
1046
1047    fn add_summary(
1048        &mut self,
1049        summary: &'a DiffTransformSummary,
1050        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1051    ) {
1052        self.output_dimension.add_summary(summary, cx);
1053        self.excerpt_dimension.add_summary(summary, cx);
1054    }
1055}
1056
1057#[derive(Clone)]
1058struct MultiBufferCursor<'a, MBD, BD> {
1059    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1060    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1061    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1062    snapshot: &'a MultiBufferSnapshot,
1063}
1064
1065#[derive(Clone)]
1066struct MultiBufferRegion<'a, MBD, BD> {
1067    buffer: &'a BufferSnapshot,
1068    is_main_buffer: bool,
1069    diff_hunk_status: Option<DiffHunkStatus>,
1070    excerpt: &'a Excerpt,
1071    buffer_range: Range<BD>,
1072    range: Range<MBD>,
1073    has_trailing_newline: bool,
1074}
1075
1076struct ExcerptChunks<'a> {
1077    content_chunks: BufferChunks<'a>,
1078    end: ExcerptAnchor,
1079    has_footer: bool,
1080}
1081
1082#[derive(Debug)]
1083struct BufferEdit {
1084    range: Range<BufferOffset>,
1085    new_text: Arc<str>,
1086    is_insertion: bool,
1087    original_indent_column: Option<u32>,
1088}
1089
1090#[derive(Clone, Copy, Debug, PartialEq)]
1091enum DiffChangeKind {
1092    BufferEdited,
1093    DiffUpdated { base_changed: bool },
1094    ExpandOrCollapseHunks { expand: bool },
1095}
1096
1097#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1098pub enum ExpandExcerptDirection {
1099    Up,
1100    Down,
1101    UpAndDown,
1102}
1103
1104impl ExpandExcerptDirection {
1105    pub fn should_expand_up(&self) -> bool {
1106        match self {
1107            ExpandExcerptDirection::Up => true,
1108            ExpandExcerptDirection::Down => false,
1109            ExpandExcerptDirection::UpAndDown => true,
1110        }
1111    }
1112
1113    pub fn should_expand_down(&self) -> bool {
1114        match self {
1115            ExpandExcerptDirection::Up => false,
1116            ExpandExcerptDirection::Down => true,
1117            ExpandExcerptDirection::UpAndDown => true,
1118        }
1119    }
1120}
1121
1122#[derive(Clone, Debug, PartialEq)]
1123pub struct IndentGuide {
1124    pub buffer_id: BufferId,
1125    pub start_row: MultiBufferRow,
1126    pub end_row: MultiBufferRow,
1127    pub depth: u32,
1128    pub tab_size: u32,
1129    pub settings: IndentGuideSettings,
1130}
1131
1132impl IndentGuide {
1133    pub fn indent_level(&self) -> u32 {
1134        self.depth * self.tab_size
1135    }
1136}
1137
1138impl MultiBuffer {
1139    pub fn new(capability: Capability) -> Self {
1140        Self::new_(
1141            capability,
1142            MultiBufferSnapshot {
1143                show_headers: true,
1144                show_deleted_hunks: true,
1145                ..MultiBufferSnapshot::default()
1146            },
1147        )
1148    }
1149
1150    pub fn without_headers(capability: Capability) -> Self {
1151        Self::new_(
1152            capability,
1153            MultiBufferSnapshot {
1154                show_deleted_hunks: true,
1155                ..MultiBufferSnapshot::default()
1156            },
1157        )
1158    }
1159
1160    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1161        let mut this = Self::new_(
1162            buffer.read(cx).capability(),
1163            MultiBufferSnapshot {
1164                singleton: true,
1165                show_deleted_hunks: true,
1166                ..MultiBufferSnapshot::default()
1167            },
1168        );
1169        this.singleton = true;
1170        this.set_excerpts_for_path(
1171            PathKey::sorted(0),
1172            buffer.clone(),
1173            [Point::zero()..buffer.read(cx).max_point()],
1174            0,
1175            cx,
1176        );
1177        this
1178    }
1179
1180    #[inline]
1181    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1182        Self {
1183            snapshot: RefCell::new(snapshot),
1184            buffers: Default::default(),
1185            diffs: HashMap::default(),
1186            subscriptions: Topic::default(),
1187            singleton: false,
1188            capability,
1189            title: None,
1190            buffer_changed_since_sync: Default::default(),
1191            history: History::default(),
1192        }
1193    }
1194
1195    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1196        let mut buffers = BTreeMap::default();
1197        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1198        for (buffer_id, buffer_state) in self.buffers.iter() {
1199            buffer_state.buffer.update(new_cx, |buffer, _| {
1200                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1201            });
1202            buffers.insert(
1203                *buffer_id,
1204                BufferState {
1205                    buffer: buffer_state.buffer.clone(),
1206                    _subscriptions: [
1207                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1208                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1209                    ],
1210                },
1211            );
1212        }
1213        let mut diff_bases = HashMap::default();
1214        for (buffer_id, diff) in self.diffs.iter() {
1215            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1216        }
1217        Self {
1218            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1219            buffers,
1220            diffs: diff_bases,
1221            subscriptions: Default::default(),
1222            singleton: self.singleton,
1223            capability: self.capability,
1224            history: self.history.clone(),
1225            title: self.title.clone(),
1226            buffer_changed_since_sync,
1227        }
1228    }
1229
1230    pub fn set_group_interval(&mut self, group_interval: Duration) {
1231        self.history.set_group_interval(group_interval);
1232    }
1233
1234    pub fn with_title(mut self, title: String) -> Self {
1235        self.title = Some(title);
1236        self
1237    }
1238
1239    pub fn read_only(&self) -> bool {
1240        !self.capability.editable()
1241    }
1242
1243    pub fn capability(&self) -> Capability {
1244        self.capability
1245    }
1246
1247    /// Returns an up-to-date snapshot of the MultiBuffer.
1248    #[ztracing::instrument(skip_all)]
1249    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1250        self.sync(cx);
1251        self.snapshot.borrow().clone()
1252    }
1253
1254    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1255        self.sync(cx);
1256        self.snapshot.borrow()
1257    }
1258
1259    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1260        if self.singleton {
1261            Some(self.buffers.values().next().unwrap().buffer.clone())
1262        } else {
1263            None
1264        }
1265    }
1266
1267    pub fn is_singleton(&self) -> bool {
1268        self.singleton
1269    }
1270
1271    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1272        self.subscriptions.subscribe()
1273    }
1274
1275    pub fn is_dirty(&self, cx: &App) -> bool {
1276        self.read(cx).is_dirty()
1277    }
1278
1279    pub fn has_deleted_file(&self, cx: &App) -> bool {
1280        self.read(cx).has_deleted_file()
1281    }
1282
1283    pub fn has_conflict(&self, cx: &App) -> bool {
1284        self.read(cx).has_conflict()
1285    }
1286
1287    // The `is_empty` signature doesn't match what clippy expects
1288    #[allow(clippy::len_without_is_empty)]
1289    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1290        self.read(cx).len()
1291    }
1292
1293    pub fn is_empty(&self) -> bool {
1294        self.buffers.is_empty()
1295    }
1296
1297    pub fn edit<I, S, T>(
1298        &mut self,
1299        edits: I,
1300        autoindent_mode: Option<AutoindentMode>,
1301        cx: &mut Context<Self>,
1302    ) where
1303        I: IntoIterator<Item = (Range<S>, T)>,
1304        S: ToOffset,
1305        T: Into<Arc<str>>,
1306    {
1307        self.edit_internal(edits, autoindent_mode, true, cx);
1308    }
1309
1310    pub fn edit_non_coalesce<I, S, T>(
1311        &mut self,
1312        edits: I,
1313        autoindent_mode: Option<AutoindentMode>,
1314        cx: &mut Context<Self>,
1315    ) where
1316        I: IntoIterator<Item = (Range<S>, T)>,
1317        S: ToOffset,
1318        T: Into<Arc<str>>,
1319    {
1320        self.edit_internal(edits, autoindent_mode, false, cx);
1321    }
1322
1323    fn edit_internal<I, S, T>(
1324        &mut self,
1325        edits: I,
1326        autoindent_mode: Option<AutoindentMode>,
1327        coalesce_adjacent: bool,
1328        cx: &mut Context<Self>,
1329    ) where
1330        I: IntoIterator<Item = (Range<S>, T)>,
1331        S: ToOffset,
1332        T: Into<Arc<str>>,
1333    {
1334        if self.read_only() || self.buffers.is_empty() {
1335            return;
1336        }
1337        self.sync_mut(cx);
1338        let edits = edits
1339            .into_iter()
1340            .map(|(range, new_text)| {
1341                let mut range = range.start.to_offset(self.snapshot.get_mut())
1342                    ..range.end.to_offset(self.snapshot.get_mut());
1343                if range.start > range.end {
1344                    mem::swap(&mut range.start, &mut range.end);
1345                }
1346                (range, new_text.into())
1347            })
1348            .collect::<Vec<_>>();
1349
1350        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1351
1352        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1353        fn edit_internal(
1354            this: &mut MultiBuffer,
1355            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1356            mut autoindent_mode: Option<AutoindentMode>,
1357            coalesce_adjacent: bool,
1358            cx: &mut Context<MultiBuffer>,
1359        ) {
1360            let original_indent_columns = match &mut autoindent_mode {
1361                Some(AutoindentMode::Block {
1362                    original_indent_columns,
1363                }) => mem::take(original_indent_columns),
1364                _ => Default::default(),
1365            };
1366
1367            let buffer_edits = MultiBuffer::convert_edits_to_buffer_edits(
1368                edits,
1369                this.snapshot.get_mut(),
1370                &original_indent_columns,
1371            );
1372
1373            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1374            for (buffer_id, mut edits) in buffer_edits {
1375                buffer_ids.push(buffer_id);
1376                edits.sort_by_key(|edit| edit.range.start);
1377                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1378                    let mut edits = edits.into_iter().peekable();
1379                    let mut insertions = Vec::new();
1380                    let mut original_indent_columns = Vec::new();
1381                    let mut deletions = Vec::new();
1382                    let empty_str: Arc<str> = Arc::default();
1383                    while let Some(BufferEdit {
1384                        mut range,
1385                        mut new_text,
1386                        mut is_insertion,
1387                        original_indent_column,
1388                    }) = edits.next()
1389                    {
1390                        while let Some(BufferEdit {
1391                            range: next_range,
1392                            is_insertion: next_is_insertion,
1393                            new_text: next_new_text,
1394                            ..
1395                        }) = edits.peek()
1396                        {
1397                            let should_coalesce = if coalesce_adjacent {
1398                                range.end >= next_range.start
1399                            } else {
1400                                range.end > next_range.start
1401                            };
1402
1403                            if should_coalesce {
1404                                range.end = cmp::max(next_range.end, range.end);
1405                                is_insertion |= *next_is_insertion;
1406                                new_text = format!("{new_text}{next_new_text}").into();
1407                                edits.next();
1408                            } else {
1409                                break;
1410                            }
1411                        }
1412
1413                        if is_insertion {
1414                            original_indent_columns.push(original_indent_column);
1415                            insertions.push((
1416                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1417                                new_text.clone(),
1418                            ));
1419                        } else if !range.is_empty() {
1420                            deletions.push((
1421                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1422                                empty_str.clone(),
1423                            ));
1424                        }
1425                    }
1426
1427                    let deletion_autoindent_mode =
1428                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1429                            Some(AutoindentMode::Block {
1430                                original_indent_columns: Default::default(),
1431                            })
1432                        } else {
1433                            autoindent_mode.clone()
1434                        };
1435                    let insertion_autoindent_mode =
1436                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1437                            Some(AutoindentMode::Block {
1438                                original_indent_columns,
1439                            })
1440                        } else {
1441                            autoindent_mode.clone()
1442                        };
1443
1444                    if coalesce_adjacent {
1445                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1446                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1447                    } else {
1448                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1449                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1450                    }
1451                })
1452            }
1453
1454            cx.emit(Event::BuffersEdited { buffer_ids });
1455        }
1456    }
1457
1458    fn convert_edits_to_buffer_edits(
1459        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1460        snapshot: &MultiBufferSnapshot,
1461        original_indent_columns: &[Option<u32>],
1462    ) -> HashMap<BufferId, Vec<BufferEdit>> {
1463        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1464        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1465        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1466            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1467
1468            cursor.seek(&range.start);
1469            let mut start_region = cursor.region().expect("start offset out of bounds");
1470            if !start_region.is_main_buffer {
1471                cursor.next();
1472                if let Some(region) = cursor.region() {
1473                    start_region = region;
1474                } else {
1475                    continue;
1476                }
1477            }
1478
1479            if range.end < start_region.range.start {
1480                continue;
1481            }
1482
1483            let start_region = start_region.clone();
1484            if range.end > start_region.range.end {
1485                cursor.seek_forward(&range.end);
1486            }
1487            let mut end_region = cursor.region().expect("end offset out of bounds");
1488            if !end_region.is_main_buffer {
1489                cursor.prev();
1490                if let Some(region) = cursor.region() {
1491                    end_region = region;
1492                } else {
1493                    continue;
1494                }
1495            }
1496
1497            if range.start > end_region.range.end {
1498                continue;
1499            }
1500
1501            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1502            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1503            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1504                .min(start_region.buffer_range.end);
1505            let buffer_end =
1506                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1507
1508            if start_region.excerpt == end_region.excerpt {
1509                if start_region.buffer.capability == Capability::ReadWrite
1510                    && start_region.is_main_buffer
1511                {
1512                    buffer_edits
1513                        .entry(start_region.buffer.remote_id())
1514                        .or_default()
1515                        .push(BufferEdit {
1516                            range: buffer_start..buffer_end,
1517                            new_text,
1518                            is_insertion: true,
1519                            original_indent_column,
1520                        });
1521                }
1522            } else {
1523                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1524                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1525                if start_region.buffer.capability == Capability::ReadWrite
1526                    && start_region.is_main_buffer
1527                {
1528                    buffer_edits
1529                        .entry(start_region.buffer.remote_id())
1530                        .or_default()
1531                        .push(BufferEdit {
1532                            range: start_excerpt_range,
1533                            new_text: new_text.clone(),
1534                            is_insertion: true,
1535                            original_indent_column,
1536                        });
1537                }
1538                if end_region.buffer.capability == Capability::ReadWrite
1539                    && end_region.is_main_buffer
1540                {
1541                    buffer_edits
1542                        .entry(end_region.buffer.remote_id())
1543                        .or_default()
1544                        .push(BufferEdit {
1545                            range: end_excerpt_range,
1546                            new_text: new_text.clone(),
1547                            is_insertion: false,
1548                            original_indent_column,
1549                        });
1550                }
1551                let end_region_excerpt = end_region.excerpt.clone();
1552
1553                cursor.seek(&range.start);
1554                cursor.next_excerpt();
1555                while let Some(region) = cursor.region() {
1556                    if region.excerpt == &end_region_excerpt {
1557                        break;
1558                    }
1559                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1560                        buffer_edits
1561                            .entry(region.buffer.remote_id())
1562                            .or_default()
1563                            .push(BufferEdit {
1564                                range: region.buffer_range.clone(),
1565                                new_text: new_text.clone(),
1566                                is_insertion: false,
1567                                original_indent_column,
1568                            });
1569                    }
1570                    cursor.next_excerpt();
1571                }
1572            }
1573        }
1574        buffer_edits
1575    }
1576
1577    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1578    where
1579        I: IntoIterator<Item = Range<S>>,
1580        S: ToOffset,
1581    {
1582        if self.read_only() || self.buffers.is_empty() {
1583            return;
1584        }
1585        self.sync_mut(cx);
1586        let empty = Arc::<str>::from("");
1587        let edits = ranges
1588            .into_iter()
1589            .map(|range| {
1590                let mut range = range.start.to_offset(self.snapshot.get_mut())
1591                    ..range.end.to_offset(&self.snapshot.get_mut());
1592                if range.start > range.end {
1593                    mem::swap(&mut range.start, &mut range.end);
1594                }
1595                (range, empty.clone())
1596            })
1597            .collect::<Vec<_>>();
1598
1599        return autoindent_ranges_internal(self, edits, cx);
1600
1601        fn autoindent_ranges_internal(
1602            this: &mut MultiBuffer,
1603            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1604            cx: &mut Context<MultiBuffer>,
1605        ) {
1606            let buffer_edits =
1607                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1608
1609            let mut buffer_ids = Vec::new();
1610            for (buffer_id, mut edits) in buffer_edits {
1611                buffer_ids.push(buffer_id);
1612                edits.sort_unstable_by_key(|edit| edit.range.start);
1613
1614                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1615                for edit in edits {
1616                    if let Some(last_range) = ranges.last_mut()
1617                        && edit.range.start <= last_range.end
1618                    {
1619                        last_range.end = last_range.end.max(edit.range.end);
1620                        continue;
1621                    }
1622                    ranges.push(edit.range);
1623                }
1624
1625                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1626                    buffer.autoindent_ranges(ranges, cx);
1627                })
1628            }
1629
1630            cx.emit(Event::BuffersEdited { buffer_ids });
1631        }
1632    }
1633
1634    pub fn set_active_selections(
1635        &self,
1636        selections: &[Selection<Anchor>],
1637        line_mode: bool,
1638        cursor_shape: CursorShape,
1639        cx: &mut Context<Self>,
1640    ) {
1641        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1642            Default::default();
1643        let snapshot = self.snapshot(cx);
1644        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(());
1645        for selection in selections {
1646            let start = selection.start.seek_target(&snapshot);
1647
1648            cursor.seek(&start, Bias::Left);
1649            while let Some(excerpt) = cursor.item() {
1650                // todo!() method?
1651                let excerpt_start =
1652                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.end);
1653                if excerpt_start.cmp(&selection.end, &snapshot).is_gt() {
1654                    break;
1655                }
1656                let buffer = excerpt.buffer_snapshot(&snapshot);
1657                let start = text::Anchor::max(
1658                    &excerpt.range.context.start,
1659                    &selection
1660                        .start
1661                        .excerpt_anchor()
1662                        .map(|excerpt_anchor| excerpt_anchor.text_anchor())
1663                        .unwrap_or(text::Anchor::MIN),
1664                    buffer,
1665                )
1666                .clone();
1667                let end = text::Anchor::min(
1668                    &excerpt.range.context.end,
1669                    &selection
1670                        .end
1671                        .excerpt_anchor()
1672                        .map(|excerpt_anchor| excerpt_anchor.text_anchor())
1673                        .unwrap_or(text::Anchor::MAX),
1674                    buffer,
1675                )
1676                .clone();
1677                selections_by_buffer
1678                    .entry(buffer.remote_id())
1679                    .or_default()
1680                    .push(Selection {
1681                        id: selection.id,
1682                        start,
1683                        end,
1684                        reversed: selection.reversed,
1685                        goal: selection.goal,
1686                    });
1687
1688                cursor.next();
1689            }
1690        }
1691
1692        for (buffer_id, buffer_state) in self.buffers.iter() {
1693            if !selections_by_buffer.contains_key(buffer_id) {
1694                buffer_state
1695                    .buffer
1696                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1697            }
1698        }
1699
1700        for (buffer_id, selections) in selections_by_buffer {
1701            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1702                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1703            });
1704        }
1705    }
1706
1707    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1708        for buffer in self.buffers.values() {
1709            buffer
1710                .buffer
1711                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1712        }
1713    }
1714
1715    #[instrument(skip_all)]
1716    fn merge_excerpt_ranges<'a>(
1717        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1718    ) -> Vec<ExcerptRange<Point>> {
1719        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1720        for range in expanded_ranges {
1721            if let Some(last_range) = merged_ranges.last_mut() {
1722                assert!(
1723                    last_range.context.start <= range.context.start,
1724                    "ranges must be sorted: {last_range:?} <= {range:?}"
1725                );
1726                if last_range.context.end >= range.context.start
1727                    || last_range.context.end.row + 1 == range.context.start.row
1728                {
1729                    last_range.context.end = range.context.end.max(last_range.context.end);
1730                    continue;
1731                }
1732            }
1733            merged_ranges.push(range.clone());
1734        }
1735        merged_ranges
1736    }
1737
1738    pub fn clear(&mut self, cx: &mut Context<Self>) {
1739        self.sync_mut(cx);
1740        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1741        let MultiBufferSnapshot {
1742            excerpts,
1743            diffs: _,
1744            diff_transforms: _,
1745            non_text_state_update_count: _,
1746            edit_count: _,
1747            is_dirty,
1748            has_deleted_file,
1749            has_conflict,
1750            has_inverted_diff,
1751            singleton: _,
1752            trailing_excerpt_update_count,
1753            all_diff_hunks_expanded: _,
1754            show_deleted_hunks: _,
1755            use_extended_diff_range: _,
1756            show_headers: _,
1757            path_keys_by_index: _,
1758            buffers,
1759        } = self.snapshot.get_mut();
1760        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1761        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1762        *excerpts = Default::default();
1763        *buffers = Default::default();
1764        *trailing_excerpt_update_count += 1;
1765        *is_dirty = false;
1766        *has_deleted_file = false;
1767        *has_conflict = false;
1768        *has_inverted_diff = false;
1769
1770        let edits = Self::sync_diff_transforms(
1771            self.snapshot.get_mut(),
1772            vec![Edit {
1773                old: start..prev_len,
1774                new: start..start,
1775            }],
1776            DiffChangeKind::BufferEdited,
1777        );
1778        if !edits.is_empty() {
1779            self.subscriptions.publish(edits);
1780        }
1781        cx.emit(Event::Edited {
1782            edited_buffer: None,
1783        });
1784        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1785        cx.notify();
1786    }
1787
1788    #[ztracing::instrument(skip_all)]
1789    pub fn excerpts_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<ExcerptInfo> {
1790        let snapshot = self.read(cx);
1791        snapshot
1792            .excerpts_for_buffer(buffer_id)
1793            .map(|excerpt| excerpt.info())
1794            .collect()
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(buffer_state) = snapshot.buffers.get(&buffer_id) else {
1808            return result;
1809        };
1810        let path_key = buffer_state.path_key.clone();
1811
1812        while let Some(excerpt) = excerpts.item()
1813            && excerpt.path_key == path_key
1814        {
1815            let excerpt_start = excerpts.start().1;
1816            let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1817
1818            diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1819            let overshoot = excerpt_start - diff_transforms.start().0;
1820            let start = diff_transforms.start().1 + overshoot;
1821
1822            diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1823            let overshoot = excerpt_end - diff_transforms.start().0;
1824            let end = diff_transforms.start().1 + overshoot;
1825
1826            result.push(start.0..end.0);
1827            excerpts.next()
1828        }
1829        result
1830    }
1831
1832    pub fn excerpt_containing(&self, position: impl ToOffset, cx: &App) -> Option<ExcerptInfo> {
1833        let snapshot = self.read(cx);
1834        let offset = position.to_offset(&snapshot);
1835
1836        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1837        cursor.seek(&offset);
1838        let excerpt = cursor.excerpt().or(snapshot.excerpts.last())?;
1839        Some(excerpt.info())
1840    }
1841
1842    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1843        match anchor {
1844            Anchor::Min => Some(self.snapshot(cx).excerpts.first()?.buffer(self)),
1845            Anchor::Excerpt(excerpt_anchor) => self.buffer(excerpt_anchor.buffer_id),
1846            Anchor::Max => Some(self.snapshot(cx).excerpts.first()?.buffer(self)),
1847        }
1848    }
1849
1850    // If point is at the end of the buffer, the last excerpt is returned
1851    pub fn point_to_buffer_offset<T: ToOffset>(
1852        &self,
1853        point: T,
1854        cx: &App,
1855    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1856        let snapshot = self.read(cx);
1857        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1858        Some((
1859            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1860            offset,
1861        ))
1862    }
1863
1864    // If point is at the end of the buffer, the last excerpt is returned
1865    pub fn point_to_buffer_point<T: ToPoint>(
1866        &self,
1867        point: T,
1868        cx: &App,
1869    ) -> Option<(Entity<Buffer>, Point)> {
1870        let snapshot = self.read(cx);
1871        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1872        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1873    }
1874
1875    pub fn buffer_point_to_anchor(
1876        &self,
1877        // todo(lw): We shouldn't need this?
1878        buffer: &Entity<Buffer>,
1879        point: Point,
1880        cx: &App,
1881    ) -> Option<Anchor> {
1882        let mut found = None;
1883        let snapshot = buffer.read(cx).snapshot();
1884        let text_anchor = snapshot.anchor_after(&point);
1885        for excerpt in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1886            if excerpt.range.contains(&text_anchor, &snapshot) {
1887                found = Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
1888                break;
1889            }
1890            if excerpt
1891                .range
1892                .context
1893                .start
1894                .cmp(&text_anchor, &snapshot)
1895                .is_gt()
1896            {
1897                found = Some(Anchor::in_buffer(
1898                    excerpt.path_key_index,
1899                    excerpt.range.context.start,
1900                ));
1901                break;
1902            }
1903            found = Some(Anchor::in_buffer(
1904                excerpt.path_key_index,
1905                excerpt.range.context.end,
1906            ));
1907        }
1908
1909        found
1910    }
1911
1912    pub fn buffer_anchor_to_anchor(
1913        &self,
1914        // todo(lw): We shouldn't need this?
1915        buffer: &Entity<Buffer>,
1916        anchor: text::Anchor,
1917        cx: &App,
1918    ) -> Option<Anchor> {
1919        let snapshot = buffer.read(cx).snapshot();
1920        for excerpt in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1921            if excerpt.range.contains(&anchor, &snapshot) {
1922                return Some(Anchor::in_buffer(excerpt.path_key_index, anchor));
1923            }
1924        }
1925
1926        None
1927    }
1928
1929    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1930        &self,
1931        anchors: Anchors,
1932        cx: &mut Context<Self>,
1933    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1934        let mut error = None;
1935        let mut futures = Vec::new();
1936        for anchor in anchors {
1937            if let Some(excerpt_anchor) = anchor.excerpt_anchor() {
1938                if let Some(buffer) = self.buffers.get(&excerpt_anchor.buffer_id) {
1939                    buffer.buffer.update(cx, |buffer, _| {
1940                        futures.push(buffer.wait_for_anchors([excerpt_anchor.text_anchor()]))
1941                    });
1942                } else {
1943                    error = Some(anyhow!(
1944                        "buffer {:?} is not part of this multi-buffer",
1945                        excerpt_anchor.buffer_id
1946                    ));
1947                    break;
1948                }
1949            }
1950        }
1951        async move {
1952            if let Some(error) = error {
1953                Err(error)?;
1954            }
1955            for future in futures {
1956                future.await?;
1957            }
1958            Ok(())
1959        }
1960    }
1961
1962    pub fn text_anchor_for_position<T: ToOffset>(
1963        &self,
1964        position: T,
1965        cx: &App,
1966    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1967        let snapshot = self.read(cx);
1968        let anchor = snapshot.anchor_before(position).excerpt_anchor()?;
1969        let buffer = self.buffers.get(&anchor.buffer_id)?.buffer.clone();
1970        Some((buffer, anchor.text_anchor()))
1971    }
1972
1973    fn on_buffer_event(
1974        &mut self,
1975        buffer: Entity<Buffer>,
1976        event: &language::BufferEvent,
1977        cx: &mut Context<Self>,
1978    ) {
1979        use language::BufferEvent;
1980        let buffer_id = buffer.read(cx).remote_id();
1981        cx.emit(match event {
1982            BufferEvent::Edited => Event::Edited {
1983                edited_buffer: Some(buffer),
1984            },
1985            BufferEvent::DirtyChanged => Event::DirtyChanged,
1986            BufferEvent::Saved => Event::Saved,
1987            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1988            BufferEvent::Reloaded => Event::Reloaded,
1989            BufferEvent::LanguageChanged(has_language) => {
1990                Event::LanguageChanged(buffer_id, *has_language)
1991            }
1992            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1993            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1994            BufferEvent::CapabilityChanged => {
1995                self.capability = buffer.read(cx).capability();
1996                return;
1997            }
1998            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1999        });
2000    }
2001
2002    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2003        let diff = diff.read(cx);
2004        let buffer_id = diff.buffer_id;
2005        let diff = DiffStateSnapshot {
2006            diff: diff.snapshot(cx),
2007            main_buffer: None,
2008        };
2009        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2010    }
2011
2012    fn inverted_buffer_diff_language_changed(
2013        &mut self,
2014        diff: Entity<BufferDiff>,
2015        main_buffer: Entity<language::Buffer>,
2016        cx: &mut Context<Self>,
2017    ) {
2018        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2019        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2020        let diff = diff.read(cx);
2021        let diff = DiffStateSnapshot {
2022            diff: diff.snapshot(cx),
2023            main_buffer: Some(main_buffer_snapshot),
2024        };
2025        self.snapshot
2026            .get_mut()
2027            .diffs
2028            .insert(base_text_buffer_id, diff);
2029    }
2030
2031    fn buffer_diff_changed(
2032        &mut self,
2033        diff: Entity<BufferDiff>,
2034        range: Range<text::Anchor>,
2035        cx: &mut Context<Self>,
2036    ) {
2037        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2038            return;
2039        };
2040        let snapshot = self.sync_mut(cx);
2041
2042        let diff = diff.read(cx);
2043        let buffer_id = diff.buffer_id;
2044
2045        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2046            return;
2047        };
2048        let new_diff = DiffStateSnapshot {
2049            diff: diff.snapshot(cx),
2050            main_buffer: None,
2051        };
2052        let base_text_changed = snapshot
2053            .diffs
2054            .get(&buffer_id)
2055            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2056        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2057
2058        let buffer = buffer.read(cx);
2059        let diff_change_range = range.to_offset(buffer);
2060
2061        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2062        let edits = Self::sync_diff_transforms(
2063            snapshot,
2064            excerpt_edits,
2065            DiffChangeKind::DiffUpdated {
2066                base_changed: base_text_changed,
2067            },
2068        );
2069        if !edits.is_empty() {
2070            self.subscriptions.publish(edits);
2071        }
2072        cx.emit(Event::Edited {
2073            edited_buffer: None,
2074        });
2075    }
2076
2077    fn inverted_buffer_diff_changed(
2078        &mut self,
2079        diff: Entity<BufferDiff>,
2080        main_buffer: Entity<language::Buffer>,
2081        diff_change_range: Option<Range<usize>>,
2082        cx: &mut Context<Self>,
2083    ) {
2084        let snapshot = self.sync_mut(cx);
2085
2086        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2087        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2088            return;
2089        };
2090
2091        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2092        let diff = diff.read(cx);
2093        let new_diff = DiffStateSnapshot {
2094            diff: diff.snapshot(cx),
2095            main_buffer: Some(main_buffer_snapshot),
2096        };
2097        snapshot
2098            .diffs
2099            .insert_or_replace(base_text_buffer_id, new_diff);
2100
2101        let Some(diff_change_range) = diff_change_range else {
2102            return;
2103        };
2104
2105        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2106        let edits = Self::sync_diff_transforms(
2107            snapshot,
2108            excerpt_edits,
2109            DiffChangeKind::DiffUpdated {
2110                // We don't read this field for inverted diffs.
2111                base_changed: false,
2112            },
2113        );
2114        if !edits.is_empty() {
2115            self.subscriptions.publish(edits);
2116        }
2117        cx.emit(Event::Edited {
2118            edited_buffer: None,
2119        });
2120    }
2121
2122    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2123        self.buffers.values().map(|state| state.buffer.clone())
2124    }
2125
2126    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2127        self.all_buffers_iter().collect()
2128    }
2129
2130    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2131        self.buffers.keys().copied()
2132    }
2133
2134    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2135        self.all_buffer_ids_iter().collect()
2136    }
2137
2138    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2139        self.buffers
2140            .get(&buffer_id)
2141            .map(|state| state.buffer.clone())
2142    }
2143
2144    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2145        self.point_to_buffer_offset(point, cx)
2146            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2147    }
2148
2149    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2150        let snapshot = self.snapshot(cx);
2151        let buffer = snapshot
2152            .excerpts
2153            .first()
2154            .map(|excerpt| excerpt.buffer(self));
2155        buffer
2156            .map(|buffer| {
2157                let buffer = buffer.read(cx);
2158                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2159            })
2160            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2161    }
2162
2163    pub fn language_settings_at<'a, T: ToOffset>(
2164        &'a self,
2165        point: T,
2166        cx: &'a App,
2167    ) -> Cow<'a, LanguageSettings> {
2168        let mut language = None;
2169        let mut file = None;
2170        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2171            let buffer = buffer.read(cx);
2172            language = buffer.language_at(offset);
2173            file = buffer.file();
2174        }
2175        language_settings(language.map(|l| l.name()), file, cx)
2176    }
2177
2178    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2179        self.buffers.values().for_each(|state| f(&state.buffer))
2180    }
2181
2182    pub fn explicit_title(&self) -> Option<&str> {
2183        self.title.as_deref()
2184    }
2185
2186    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2187        if let Some(title) = self.title.as_ref() {
2188            return title.into();
2189        }
2190
2191        if let Some(buffer) = self.as_singleton() {
2192            let buffer = buffer.read(cx);
2193
2194            if let Some(file) = buffer.file() {
2195                return file.file_name(cx).into();
2196            }
2197
2198            if let Some(title) = self.buffer_content_title(buffer) {
2199                return title;
2200            }
2201        };
2202
2203        "untitled".into()
2204    }
2205
2206    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2207        let mut is_leading_whitespace = true;
2208        let mut count = 0;
2209        let mut prev_was_space = false;
2210        let mut title = String::new();
2211
2212        for ch in buffer.snapshot().chars() {
2213            if is_leading_whitespace && ch.is_whitespace() {
2214                continue;
2215            }
2216
2217            is_leading_whitespace = false;
2218
2219            if ch == '\n' || count >= 40 {
2220                break;
2221            }
2222
2223            if ch.is_whitespace() {
2224                if !prev_was_space {
2225                    title.push(' ');
2226                    count += 1;
2227                    prev_was_space = true;
2228                }
2229            } else {
2230                title.push(ch);
2231                count += 1;
2232                prev_was_space = false;
2233            }
2234        }
2235
2236        let title = title.trim_end().to_string();
2237
2238        if title.is_empty() {
2239            return None;
2240        }
2241
2242        Some(title.into())
2243    }
2244
2245    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2246        self.title = Some(title);
2247        cx.notify();
2248    }
2249
2250    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2251    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2252        for buffer_state in self.buffers.values() {
2253            buffer_state
2254                .buffer
2255                .update(cx, |buffer, _cx| buffer.refresh_preview());
2256        }
2257    }
2258
2259    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2260    pub fn preserve_preview(&self, cx: &App) -> bool {
2261        self.buffers
2262            .values()
2263            .all(|state| state.buffer.read(cx).preserve_preview())
2264    }
2265
2266    #[cfg(any(test, feature = "test-support"))]
2267    pub fn is_parsing(&self, cx: &App) -> bool {
2268        self.as_singleton().unwrap().read(cx).is_parsing()
2269    }
2270
2271    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2272        let buffer_id = diff.read(cx).buffer_id;
2273
2274        if let Some(existing_diff) = self.diff_for(buffer_id)
2275            && diff.entity_id() == existing_diff.entity_id()
2276        {
2277            return;
2278        }
2279
2280        self.buffer_diff_changed(
2281            diff.clone(),
2282            text::Anchor::min_max_range_for_buffer(buffer_id),
2283            cx,
2284        );
2285        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2286    }
2287
2288    pub fn add_inverted_diff(
2289        &mut self,
2290        diff: Entity<BufferDiff>,
2291        main_buffer: Entity<language::Buffer>,
2292        cx: &mut Context<Self>,
2293    ) {
2294        let snapshot = diff.read(cx).base_text(cx);
2295        let base_text_buffer_id = snapshot.remote_id();
2296        let diff_change_range = 0..snapshot.len();
2297        self.snapshot.get_mut().has_inverted_diff = true;
2298        self.inverted_buffer_diff_changed(
2299            diff.clone(),
2300            main_buffer.clone(),
2301            Some(diff_change_range),
2302            cx,
2303        );
2304        self.diffs.insert(
2305            base_text_buffer_id,
2306            DiffState::new_inverted(diff, main_buffer, cx),
2307        );
2308    }
2309
2310    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2311        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2312    }
2313
2314    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2315        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2316    }
2317
2318    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2319        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2320    }
2321
2322    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2323        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2324        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2325    }
2326
2327    pub fn all_diff_hunks_expanded(&self) -> bool {
2328        self.snapshot.borrow().all_diff_hunks_expanded
2329    }
2330
2331    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2332        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2333        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2334    }
2335
2336    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2337        self.snapshot.get_mut().show_deleted_hunks = show;
2338
2339        self.sync_mut(cx);
2340
2341        let old_len = self.snapshot.borrow().len();
2342
2343        let ranges = std::iter::once((Point::zero()..Point::MAX, Anchor::Max));
2344        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2345
2346        let new_len = self.snapshot.borrow().len();
2347
2348        self.subscriptions.publish(vec![Edit {
2349            old: MultiBufferOffset(0)..old_len,
2350            new: MultiBufferOffset(0)..new_len,
2351        }]);
2352
2353        cx.emit(Event::DiffHunksToggled);
2354        cx.emit(Event::Edited {
2355            edited_buffer: None,
2356        });
2357    }
2358
2359    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2360        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2361    }
2362
2363    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2364        self.read(cx)
2365            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2366            .nth(1)
2367            .is_some()
2368    }
2369
2370    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2371        let snapshot = self.read(cx);
2372        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2373        let offset_range = range.to_offset(&snapshot);
2374        cursor.seek(&offset_range.start, Bias::Left);
2375        while let Some(item) = cursor.item() {
2376            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2377                break;
2378            }
2379            if item.hunk_info().is_some() {
2380                return true;
2381            }
2382            cursor.next();
2383        }
2384        false
2385    }
2386
2387    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2388        let snapshot = self.read(cx);
2389        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2390        for range in ranges {
2391            let range = range.to_point(&snapshot);
2392            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2393            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2394                .min(snapshot.len());
2395            cursor.seek(&start, Bias::Right);
2396            while let Some(item) = cursor.item() {
2397                if *cursor.start() >= end {
2398                    break;
2399                }
2400                if item.hunk_info().is_some() {
2401                    return true;
2402                }
2403                cursor.next();
2404            }
2405        }
2406        false
2407    }
2408
2409    pub fn expand_or_collapse_diff_hunks_inner(
2410        &mut self,
2411        // second element is the end of the last excerpt that should be considered for this range
2412        // (or Anchor::Max to opt out)
2413        ranges: impl IntoIterator<Item = (Range<Point>, Anchor)>,
2414        expand: bool,
2415        cx: &mut Context<Self>,
2416    ) -> Vec<Edit<MultiBufferOffset>> {
2417        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2418            return Vec::new();
2419        }
2420        self.sync_mut(cx);
2421        let mut snapshot = self.snapshot.get_mut();
2422        let mut excerpt_edits = Vec::new();
2423        let mut last_hunk_row = None;
2424        for (range, excerpt_end) in ranges {
2425            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2426                if diff_hunk
2427                    .multi_buffer_range()
2428                    .end
2429                    .cmp(&excerpt_end, &snapshot)
2430                    .is_gt()
2431                {
2432                    continue;
2433                }
2434                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2435                    continue;
2436                }
2437                let range = diff_hunk.multi_buffer_range();
2438                let start = snapshot.excerpt_offset_for_anchor(&range.start);
2439                let end = snapshot.excerpt_offset_for_anchor(&range.end);
2440                last_hunk_row = Some(diff_hunk.row_range.start);
2441                excerpt_edits.push(text::Edit {
2442                    old: start..end,
2443                    new: start..end,
2444                });
2445            }
2446        }
2447
2448        Self::sync_diff_transforms(
2449            &mut snapshot,
2450            excerpt_edits,
2451            DiffChangeKind::ExpandOrCollapseHunks { expand },
2452        )
2453    }
2454
2455    pub fn expand_or_collapse_diff_hunks(
2456        &mut self,
2457        ranges: Vec<Range<Anchor>>,
2458        expand: bool,
2459        cx: &mut Context<Self>,
2460    ) {
2461        let snapshot = self.snapshot.borrow().clone();
2462        let ranges = ranges.iter().map(move |range| {
2463            let excerpt_end = snapshot
2464                .excerpt_containing(range.end..range.end)
2465                .map(|excerpt| excerpt.end_anchor().into())
2466                .unwrap_or(Anchor::Max);
2467            let range = range.to_point(&snapshot);
2468            let mut peek_end = range.end;
2469            if range.end.row < snapshot.max_row().0 {
2470                peek_end = Point::new(range.end.row + 1, 0);
2471            };
2472            (range.start..peek_end, excerpt_end)
2473        });
2474        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2475        if !edits.is_empty() {
2476            self.subscriptions.publish(edits);
2477        }
2478        cx.emit(Event::DiffHunksToggled);
2479        cx.emit(Event::Edited {
2480            edited_buffer: None,
2481        });
2482    }
2483
2484    #[ztracing::instrument(skip_all)]
2485    fn sync(&self, cx: &App) {
2486        let changed = self.buffer_changed_since_sync.replace(false);
2487        if !changed {
2488            return;
2489        }
2490        let edits = Self::sync_from_buffer_changes(
2491            &mut self.snapshot.borrow_mut(),
2492            &self.buffers,
2493            &self.diffs,
2494            cx,
2495        );
2496        if !edits.is_empty() {
2497            self.subscriptions.publish(edits);
2498        }
2499    }
2500
2501    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2502        let snapshot = self.snapshot.get_mut();
2503        let changed = self.buffer_changed_since_sync.replace(false);
2504        if !changed {
2505            return snapshot;
2506        }
2507        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2508        dbg!(&edits);
2509
2510        if !edits.is_empty() {
2511            self.subscriptions.publish(edits);
2512        }
2513
2514        snapshot
2515    }
2516
2517    fn sync_from_buffer_changes(
2518        snapshot: &mut MultiBufferSnapshot,
2519        buffers: &BTreeMap<BufferId, BufferState>,
2520        diffs: &HashMap<BufferId, DiffState>,
2521        cx: &App,
2522    ) -> Vec<Edit<MultiBufferOffset>> {
2523        let MultiBufferSnapshot {
2524            excerpts,
2525            diffs: buffer_diff,
2526            buffers: buffer_snapshots,
2527            path_keys_by_index: _,
2528            diff_transforms: _,
2529            non_text_state_update_count,
2530            edit_count,
2531            is_dirty,
2532            has_deleted_file,
2533            has_conflict,
2534            has_inverted_diff: _,
2535            singleton: _,
2536            trailing_excerpt_update_count: _,
2537            all_diff_hunks_expanded: _,
2538            show_deleted_hunks: _,
2539            use_extended_diff_range: _,
2540            show_headers: _,
2541        } = snapshot;
2542        *is_dirty = false;
2543        *has_deleted_file = false;
2544        *has_conflict = false;
2545
2546        if !diffs.is_empty() {
2547            let mut diffs_to_add = Vec::new();
2548            for (id, diff) in diffs {
2549                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2550                // and use the diff hunk base text ranges to compute diff transforms.
2551                // Those base text ranges are usize, so make sure if the base text changed
2552                // we also update the diff snapshot so that we don't use stale offsets
2553                if buffer_diff.get(id).is_none_or(|existing_diff| {
2554                    if existing_diff.main_buffer.is_none() {
2555                        return false;
2556                    }
2557                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2558                    base_text.remote_id() != existing_diff.base_text().remote_id()
2559                        || base_text
2560                            .version()
2561                            .changed_since(existing_diff.base_text().version())
2562                }) {
2563                    if diffs_to_add.capacity() == 0 {
2564                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2565                        // meaning re-allocations will be fairly expensive
2566                        diffs_to_add.reserve(diffs.len());
2567                    }
2568                    diffs_to_add.push((*id, diff.snapshot(cx)));
2569                }
2570            }
2571            buffer_diff.extend(diffs_to_add);
2572        }
2573
2574        let mut paths_to_edit = Vec::new();
2575        let mut non_text_state_updated = false;
2576        let mut edited = false;
2577        for buffer_state in buffers.values() {
2578            let buffer = buffer_state.buffer.read(cx);
2579            let last_snapshot = buffer_snapshots
2580                .get(&buffer.remote_id())
2581                .expect("each buffer should have a snapshot");
2582            let current_version = buffer.version();
2583            let non_text_state_update_count = buffer.non_text_state_update_count();
2584
2585            let buffer_edited =
2586                current_version.changed_since(last_snapshot.buffer_snapshot.version());
2587            dbg!(
2588                &current_version,
2589                last_snapshot.buffer_snapshot.version().clone()
2590            );
2591            let buffer_non_text_state_updated = non_text_state_update_count
2592                > last_snapshot.buffer_snapshot.non_text_state_update_count();
2593            if buffer_edited || buffer_non_text_state_updated {
2594                paths_to_edit.push((
2595                    last_snapshot.path_key.clone(),
2596                    buffer_state.buffer.clone(),
2597                    if buffer_edited {
2598                        Some(last_snapshot.buffer_snapshot.version().clone())
2599                    } else {
2600                        None
2601                    },
2602                ));
2603            }
2604
2605            edited |= buffer_edited;
2606            non_text_state_updated |= buffer_non_text_state_updated;
2607            *is_dirty |= buffer.is_dirty();
2608            *has_deleted_file |= buffer
2609                .file()
2610                .is_some_and(|file| file.disk_state().is_deleted());
2611            *has_conflict |= buffer.has_conflict();
2612        }
2613        if edited {
2614            *edit_count += 1;
2615        }
2616        if non_text_state_updated {
2617            *non_text_state_update_count += 1;
2618        }
2619
2620        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path.clone());
2621
2622        let mut edits = Vec::new();
2623        let mut new_excerpts = SumTree::default();
2624        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2625
2626        for (path, buffer, prev_version) in paths_to_edit {
2627            dbg!(&prev_version, buffer.read(cx).version());
2628            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2629            let old_excerpt = cursor.item().unwrap();
2630            let buffer = buffer.read(cx);
2631            let buffer_id = buffer.remote_id();
2632
2633            buffer_snapshots.insert(
2634                buffer_id,
2635                BufferStateSnapshot {
2636                    path_key: path.clone(),
2637                    buffer_snapshot: buffer.snapshot(),
2638                },
2639            );
2640
2641            let new_excerpt = if let Some(prev_version) = prev_version {
2642                edits.extend(
2643                    buffer
2644                        .edits_since_in_range::<usize>(
2645                            &prev_version,
2646                            dbg!(old_excerpt.range.context.clone()),
2647                        )
2648                        .map(|edit| {
2649                            dbg!(&edit);
2650                            let excerpt_old_start = cursor.start().len();
2651                            let excerpt_new_start =
2652                                ExcerptDimension(new_excerpts.summary().text.len);
2653                            let old_start = excerpt_old_start + edit.old.start;
2654                            let old_end = excerpt_old_start + edit.old.end;
2655                            let new_start = excerpt_new_start + edit.new.start;
2656                            let new_end = excerpt_new_start + edit.new.end;
2657                            Edit {
2658                                old: old_start..old_end,
2659                                new: new_start..new_end,
2660                            }
2661                        }),
2662                );
2663
2664                Excerpt::new(
2665                    path,
2666                    old_excerpt.path_key_index,
2667                    &buffer.snapshot(),
2668                    old_excerpt.range.clone(),
2669                    old_excerpt.has_trailing_newline,
2670                )
2671            } else {
2672                old_excerpt.clone()
2673            };
2674
2675            new_excerpts.push(new_excerpt, ());
2676            cursor.next();
2677        }
2678        new_excerpts.append(cursor.suffix(), ());
2679
2680        drop(cursor);
2681        *excerpts = new_excerpts;
2682
2683        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2684    }
2685
2686    fn sync_diff_transforms(
2687        snapshot: &mut MultiBufferSnapshot,
2688        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2689        change_kind: DiffChangeKind,
2690    ) -> Vec<Edit<MultiBufferOffset>> {
2691        dbg!(&excerpt_edits);
2692        if excerpt_edits.is_empty() {
2693            return vec![];
2694        }
2695
2696        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2697        let mut old_diff_transforms = snapshot
2698            .diff_transforms
2699            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2700        let mut new_diff_transforms = SumTree::default();
2701        let mut old_expanded_hunks = HashSet::default();
2702        let mut output_edits = Vec::new();
2703        let mut output_delta = 0_isize;
2704        let mut at_transform_boundary = true;
2705        let mut end_of_current_insert = None;
2706
2707        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2708        while let Some(edit) = excerpt_edits.next() {
2709            excerpts.seek_forward(&edit.new.start, Bias::Right);
2710            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2711                excerpts.prev();
2712            }
2713
2714            // Keep any transforms that are before the edit.
2715            if at_transform_boundary {
2716                at_transform_boundary = false;
2717                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2718                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2719                if let Some(transform) = old_diff_transforms.item()
2720                    && old_diff_transforms.end().0 == edit.old.start
2721                    && old_diff_transforms.start().0 < edit.old.start
2722                {
2723                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2724                    old_diff_transforms.next();
2725                }
2726            }
2727
2728            // Compute the start of the edit in output coordinates.
2729            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2730            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2731            let edit_new_start =
2732                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2733
2734            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2735                &edit,
2736                &mut excerpts,
2737                &mut old_diff_transforms,
2738                &mut new_diff_transforms,
2739                &mut end_of_current_insert,
2740                &mut old_expanded_hunks,
2741                snapshot,
2742                change_kind,
2743            );
2744
2745            // Compute the end of the edit in output coordinates.
2746            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2747            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2748            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2749            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2750            let output_edit = Edit {
2751                old: edit_old_start..edit_old_end,
2752                new: edit_new_start..edit_new_end,
2753            };
2754
2755            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2756            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2757            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2758                output_edits.push(output_edit);
2759            }
2760
2761            // If this is the last edit that intersects the current diff transform,
2762            // then recreate the content up to the end of this transform, to prepare
2763            // for reusing additional slices of the old transforms.
2764            if excerpt_edits
2765                .peek()
2766                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2767            {
2768                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2769                    && match old_diff_transforms.item() {
2770                        Some(DiffTransform::BufferContent {
2771                            inserted_hunk_info: Some(hunk),
2772                            ..
2773                        }) => excerpts.item().is_some_and(|excerpt| {
2774                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2775                                && diff.main_buffer.is_some()
2776                            {
2777                                return true;
2778                            }
2779                            hunk.hunk_start_anchor
2780                                .is_valid(&excerpt.buffer_snapshot(&snapshot))
2781                        }),
2782                        _ => true,
2783                    };
2784
2785                let mut excerpt_offset = edit.new.end;
2786                if !keep_next_old_transform {
2787                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2788                    old_diff_transforms.next();
2789                }
2790
2791                old_expanded_hunks.clear();
2792                Self::push_buffer_content_transform(
2793                    snapshot,
2794                    &mut new_diff_transforms,
2795                    excerpt_offset,
2796                    end_of_current_insert,
2797                );
2798                at_transform_boundary = true;
2799            }
2800        }
2801
2802        // Keep any transforms that are after the last edit.
2803        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2804
2805        // Ensure there's always at least one buffer content transform.
2806        if new_diff_transforms.is_empty() {
2807            new_diff_transforms.push(
2808                DiffTransform::BufferContent {
2809                    summary: Default::default(),
2810                    inserted_hunk_info: None,
2811                },
2812                (),
2813            );
2814        }
2815
2816        drop(old_diff_transforms);
2817        drop(excerpts);
2818        snapshot.diff_transforms = new_diff_transforms;
2819        snapshot.edit_count += 1;
2820
2821        #[cfg(any(test, feature = "test-support"))]
2822        snapshot.check_invariants();
2823        output_edits
2824    }
2825
2826    fn recompute_diff_transforms_for_edit(
2827        edit: &Edit<ExcerptOffset>,
2828        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2829        old_diff_transforms: &mut Cursor<
2830            DiffTransform,
2831            Dimensions<ExcerptOffset, MultiBufferOffset>,
2832        >,
2833        new_diff_transforms: &mut SumTree<DiffTransform>,
2834        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2835        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2836        snapshot: &MultiBufferSnapshot,
2837        change_kind: DiffChangeKind,
2838    ) -> bool {
2839        log::trace!(
2840            "recomputing diff transform for edit {:?} => {:?}",
2841            edit.old.start..edit.old.end,
2842            edit.new.start..edit.new.end
2843        );
2844
2845        // Record which hunks were previously expanded.
2846        while let Some(item) = old_diff_transforms.item() {
2847            if let Some(hunk_info) = item.hunk_info() {
2848                log::trace!(
2849                    "previously expanded hunk at {:?}",
2850                    old_diff_transforms.start()
2851                );
2852                old_expanded_hunks.insert(hunk_info);
2853            }
2854            if old_diff_transforms.end().0 > edit.old.end {
2855                break;
2856            }
2857            old_diff_transforms.next();
2858        }
2859
2860        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2861        // For inverted diffs, hunks are always shown, so we can't skip this.
2862        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2863        if old_expanded_hunks.is_empty()
2864            && change_kind == DiffChangeKind::BufferEdited
2865            && !all_diff_hunks_expanded
2866            && !snapshot.has_inverted_diff
2867        {
2868            return false;
2869        }
2870
2871        // Visit each excerpt that intersects the edit.
2872        let mut did_expand_hunks = false;
2873        while let Some(excerpt) = excerpts.item() {
2874            // Recompute the expanded hunks in the portion of the excerpt that
2875            // intersects the edit.
2876            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2877                let buffer_snapshot = &excerpt.buffer_snapshot(&snapshot);
2878                let excerpt_start = *excerpts.start();
2879                let excerpt_end = excerpt_start + excerpt.text_summary.len;
2880                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer_snapshot);
2881                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2882                let edit_buffer_start =
2883                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
2884                let edit_buffer_end =
2885                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
2886                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2887
2888                if let Some(main_buffer) = &diff.main_buffer {
2889                    for hunk in diff.hunks_intersecting_base_text_range(
2890                        edit_buffer_start..edit_buffer_end,
2891                        main_buffer,
2892                    ) {
2893                        did_expand_hunks = true;
2894                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
2895                        if hunk_buffer_range.start < excerpt_buffer_start {
2896                            log::trace!("skipping hunk that starts before excerpt");
2897                            continue;
2898                        }
2899                        hunk_buffer_range
2900                            .end
2901                            .to_point(&excerpt.buffer_snapshot(&snapshot));
2902                        let hunk_excerpt_start = excerpt_start
2903                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2904                        let hunk_excerpt_end = excerpt_end
2905                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2906                        Self::push_buffer_content_transform(
2907                            snapshot,
2908                            new_diff_transforms,
2909                            hunk_excerpt_start,
2910                            *end_of_current_insert,
2911                        );
2912                        if !hunk_buffer_range.is_empty() {
2913                            let hunk_info = DiffTransformHunkInfo {
2914                                buffer_id: buffer_snapshot.remote_id(),
2915                                hunk_start_anchor: hunk.buffer_range.start,
2916                                hunk_secondary_status: hunk.secondary_status,
2917                                excerpt_end: excerpt.end_anchor(),
2918                                is_logically_deleted: true,
2919                            };
2920                            *end_of_current_insert =
2921                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2922                        }
2923                    }
2924                } else {
2925                    let edit_anchor_range = buffer_snapshot.anchor_before(edit_buffer_start)
2926                        ..buffer_snapshot.anchor_after(edit_buffer_end);
2927                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer_snapshot) {
2928                        if hunk.is_created_file() && !all_diff_hunks_expanded {
2929                            continue;
2930                        }
2931
2932                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer_snapshot);
2933                        if hunk_buffer_range.start < excerpt_buffer_start {
2934                            log::trace!("skipping hunk that starts before excerpt");
2935                            continue;
2936                        }
2937
2938                        let hunk_info = DiffTransformHunkInfo {
2939                            buffer_id: buffer_snapshot.remote_id(),
2940                            hunk_start_anchor: hunk.buffer_range.start,
2941                            hunk_secondary_status: hunk.secondary_status,
2942                            excerpt_end: excerpt.end_anchor(),
2943                            is_logically_deleted: false,
2944                        };
2945
2946                        let hunk_excerpt_start = excerpt_start
2947                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2948                        let hunk_excerpt_end = excerpt_end
2949                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2950
2951                        Self::push_buffer_content_transform(
2952                            snapshot,
2953                            new_diff_transforms,
2954                            hunk_excerpt_start,
2955                            *end_of_current_insert,
2956                        );
2957
2958                        // For every existing hunk, determine if it was previously expanded
2959                        // and if it should currently be expanded.
2960                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2961                        let should_expand_hunk = match &change_kind {
2962                            DiffChangeKind::DiffUpdated { base_changed: true } => {
2963                                was_previously_expanded || all_diff_hunks_expanded
2964                            }
2965                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2966                                let intersects = hunk_buffer_range.is_empty()
2967                                    || hunk_buffer_range.end > edit_buffer_start;
2968                                if *expand {
2969                                    intersects || was_previously_expanded || all_diff_hunks_expanded
2970                                } else {
2971                                    !intersects
2972                                        && (was_previously_expanded || all_diff_hunks_expanded)
2973                                }
2974                            }
2975                            _ => was_previously_expanded || all_diff_hunks_expanded,
2976                        };
2977
2978                        if should_expand_hunk {
2979                            did_expand_hunks = true;
2980                            log::trace!(
2981                                "expanding hunk {:?}",
2982                                hunk_excerpt_start..hunk_excerpt_end,
2983                            );
2984
2985                            if !hunk.diff_base_byte_range.is_empty()
2986                                && hunk_buffer_range.start >= edit_buffer_start
2987                                && hunk_buffer_range.start <= excerpt_buffer_end
2988                                && snapshot.show_deleted_hunks
2989                            {
2990                                let base_text = diff.base_text();
2991                                let mut text_cursor =
2992                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2993                                let mut base_text_summary = text_cursor
2994                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
2995
2996                                let mut has_trailing_newline = false;
2997                                if base_text_summary.last_line_chars > 0 {
2998                                    base_text_summary += TextSummary::newline();
2999                                    has_trailing_newline = true;
3000                                }
3001
3002                                new_diff_transforms.push(
3003                                    DiffTransform::DeletedHunk {
3004                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3005                                        summary: base_text_summary,
3006                                        buffer_id: buffer_snapshot.remote_id(),
3007                                        hunk_info,
3008                                        has_trailing_newline,
3009                                    },
3010                                    (),
3011                                );
3012                            }
3013
3014                            if !hunk_buffer_range.is_empty() {
3015                                *end_of_current_insert =
3016                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3017                            }
3018                        }
3019                    }
3020                }
3021            }
3022
3023            if excerpts.end() <= edit.new.end {
3024                excerpts.next();
3025            } else {
3026                break;
3027            }
3028        }
3029
3030        did_expand_hunks || !old_expanded_hunks.is_empty()
3031    }
3032
3033    fn append_diff_transforms(
3034        new_transforms: &mut SumTree<DiffTransform>,
3035        subtree: SumTree<DiffTransform>,
3036    ) {
3037        if let Some(DiffTransform::BufferContent {
3038            inserted_hunk_info,
3039            summary,
3040        }) = subtree.first()
3041            && Self::extend_last_buffer_content_transform(
3042                new_transforms,
3043                *inserted_hunk_info,
3044                *summary,
3045            )
3046        {
3047            let mut cursor = subtree.cursor::<()>(());
3048            cursor.next();
3049            cursor.next();
3050            new_transforms.append(cursor.suffix(), ());
3051            return;
3052        }
3053        new_transforms.append(subtree, ());
3054    }
3055
3056    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3057        if let DiffTransform::BufferContent {
3058            inserted_hunk_info: inserted_hunk_anchor,
3059            summary,
3060        } = transform
3061            && Self::extend_last_buffer_content_transform(
3062                new_transforms,
3063                inserted_hunk_anchor,
3064                summary,
3065            )
3066        {
3067            return;
3068        }
3069        new_transforms.push(transform, ());
3070    }
3071
3072    fn push_buffer_content_transform(
3073        old_snapshot: &MultiBufferSnapshot,
3074        new_transforms: &mut SumTree<DiffTransform>,
3075        end_offset: ExcerptOffset,
3076        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3077    ) {
3078        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3079            (end_offset.min(insertion_end_offset), Some(hunk_info))
3080        });
3081        let unchanged_region = [(end_offset, None)];
3082
3083        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3084        {
3085            let start_offset = new_transforms.summary().excerpt_len();
3086            if end_offset <= start_offset {
3087                continue;
3088            }
3089            let summary_to_add = old_snapshot
3090                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3091
3092            if !Self::extend_last_buffer_content_transform(
3093                new_transforms,
3094                inserted_hunk_info,
3095                summary_to_add,
3096            ) {
3097                new_transforms.push(
3098                    DiffTransform::BufferContent {
3099                        summary: summary_to_add,
3100                        inserted_hunk_info,
3101                    },
3102                    (),
3103                )
3104            }
3105        }
3106    }
3107
3108    fn extend_last_buffer_content_transform(
3109        new_transforms: &mut SumTree<DiffTransform>,
3110        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3111        summary_to_add: MBTextSummary,
3112    ) -> bool {
3113        let mut did_extend = false;
3114        new_transforms.update_last(
3115            |last_transform| {
3116                if let DiffTransform::BufferContent {
3117                    summary,
3118                    inserted_hunk_info: inserted_hunk_anchor,
3119                } = last_transform
3120                    && *inserted_hunk_anchor == new_inserted_hunk_info
3121                {
3122                    *summary += summary_to_add;
3123                    did_extend = true;
3124                }
3125            },
3126            (),
3127        );
3128        did_extend
3129    }
3130
3131    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3132        let snapshot = self.snapshot(cx);
3133        let excerpt_end = snapshot
3134            .excerpt_containing(range.end..range.end)
3135            .map(|excerpt| excerpt.end_anchor().into())
3136            .unwrap_or(Anchor::Max);
3137        let point_range = range.to_point(&snapshot);
3138        let expand = !self.single_hunk_is_expanded(range, cx);
3139        let edits =
3140            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_end)], expand, cx);
3141        if !edits.is_empty() {
3142            self.subscriptions.publish(edits);
3143        }
3144        cx.emit(Event::DiffHunksToggled);
3145        cx.emit(Event::Edited {
3146            edited_buffer: None,
3147        });
3148    }
3149}
3150
3151fn build_excerpt_ranges(
3152    ranges: impl IntoIterator<Item = Range<Point>>,
3153    context_line_count: u32,
3154    buffer_snapshot: &BufferSnapshot,
3155) -> Vec<ExcerptRange<Point>> {
3156    ranges
3157        .into_iter()
3158        .map(|range| {
3159            let start_row = range.start.row.saturating_sub(context_line_count);
3160            let start = Point::new(start_row, 0);
3161            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3162            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3163            ExcerptRange {
3164                context: start..end,
3165                primary: range,
3166            }
3167        })
3168        .collect()
3169}
3170
3171#[cfg(any(test, feature = "test-support"))]
3172impl MultiBuffer {
3173    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3174        let buffer = cx.new(|cx| Buffer::local(text, cx));
3175        cx.new(|cx| Self::singleton(buffer, cx))
3176    }
3177
3178    pub fn build_multi<const COUNT: usize>(
3179        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3180        cx: &mut gpui::App,
3181    ) -> Entity<Self> {
3182        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3183        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3184            let buffer = cx.new(|cx| Buffer::local(text, cx));
3185            let snapshot = buffer.read(cx).snapshot();
3186            let excerpt_ranges = ranges
3187                .into_iter()
3188                .map(ExcerptRange::new)
3189                .collect::<Vec<_>>();
3190            multi.update(cx, |multi, cx| {
3191                multi.set_excerpt_ranges_for_path(
3192                    PathKey::sorted(ix as u64),
3193                    buffer,
3194                    &snapshot,
3195                    excerpt_ranges,
3196                    cx,
3197                )
3198            });
3199        }
3200
3201        multi
3202    }
3203
3204    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3205        cx.new(|cx| Self::singleton(buffer, cx))
3206    }
3207
3208    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3209        cx.new(|cx| {
3210            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3211            let mutation_count = rng.random_range(1..=5);
3212            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3213            multibuffer
3214        })
3215    }
3216
3217    pub fn randomly_edit(
3218        &mut self,
3219        rng: &mut impl rand::Rng,
3220        edit_count: usize,
3221        cx: &mut Context<Self>,
3222    ) {
3223        use util::RandomCharIter;
3224
3225        let snapshot = self.read(cx);
3226        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3227        let mut last_end = None;
3228        for _ in 0..edit_count {
3229            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3230                break;
3231            }
3232
3233            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3234            let end =
3235                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3236            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3237            last_end = Some(end);
3238
3239            let mut range = start..end;
3240            if rng.random_bool(0.2) {
3241                mem::swap(&mut range.start, &mut range.end);
3242            }
3243
3244            let new_text_len = rng.random_range(0..10);
3245            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3246
3247            edits.push((range, new_text.into()));
3248        }
3249        log::info!("mutating multi-buffer with {:?}", edits);
3250        drop(snapshot);
3251
3252        self.edit(edits, None, cx);
3253    }
3254
3255    pub fn randomly_edit_excerpts(
3256        &mut self,
3257        rng: &mut impl rand::Rng,
3258        mutation_count: usize,
3259        cx: &mut Context<Self>,
3260    ) {
3261        use rand::prelude::*;
3262        use std::env;
3263        use util::RandomCharIter;
3264
3265        let max_buffers = env::var("MAX_BUFFERS")
3266            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3267            .unwrap_or(5);
3268
3269        let mut buffers = Vec::new();
3270        for _ in 0..mutation_count {
3271            let buffer_ids = self.all_buffer_ids();
3272            if buffer_ids.is_empty() || (rng.random() && buffer_ids.len() < max_buffers) {
3273                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3274                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3275                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3276                    let buffer = buffers.last().unwrap().read(cx);
3277                    log::info!(
3278                        "Creating new buffer {} with text: {:?}",
3279                        buffer.remote_id(),
3280                        buffer.text()
3281                    );
3282                    buffers.last().unwrap().clone()
3283                } else {
3284                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3285                };
3286
3287                let buffer = buffer_handle.read(cx);
3288                let buffer_text = buffer.text();
3289                let buffer_snapshot = buffer.snapshot();
3290                let mut next_min_start_ix = 0;
3291                let ranges = (0..rng.random_range(0..5))
3292                    .filter_map(|_| {
3293                        if next_min_start_ix == buffer.len() {
3294                            return None;
3295                        }
3296                        let end_ix = buffer.clip_offset(
3297                            rng.random_range(next_min_start_ix..=buffer.len()),
3298                            Bias::Right,
3299                        );
3300                        let start_ix = buffer
3301                            .clip_offset(rng.random_range(next_min_start_ix..=end_ix), Bias::Left);
3302                        next_min_start_ix = end_ix;
3303                        Some(ExcerptRange::new(start_ix..end_ix))
3304                    })
3305                    .collect::<Vec<_>>();
3306                log::info!(
3307                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3308                    buffer_handle.read(cx).remote_id(),
3309                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3310                    ranges
3311                        .iter()
3312                        .map(|r| &buffer_text[r.context.clone()])
3313                        .collect::<Vec<_>>()
3314                );
3315
3316                let path_key = PathKey::sorted(rng.random_range(0..max_buffers * 3) as u64);
3317                self.set_merged_excerpt_ranges_for_path(
3318                    path_key.clone(),
3319                    buffer_handle,
3320                    &buffer_snapshot,
3321                    ranges,
3322                    cx,
3323                );
3324                log::info!("Inserted with path_key: {:?}", path_key);
3325            } else {
3326                let path_key = self
3327                    .snapshot
3328                    .borrow()
3329                    .buffers
3330                    .get(&buffer_ids.choose(rng).unwrap())
3331                    .unwrap()
3332                    .path_key
3333                    .clone();
3334                log::info!("Removing excerpts {:?}", path_key);
3335                self.remove_excerpts_for_path(path_key, cx);
3336            }
3337        }
3338    }
3339
3340    pub fn randomly_mutate(
3341        &mut self,
3342        rng: &mut impl rand::Rng,
3343        mutation_count: usize,
3344        cx: &mut Context<Self>,
3345    ) {
3346        use rand::prelude::*;
3347
3348        if rng.random_bool(0.7) || self.singleton {
3349            let buffer = self
3350                .buffers
3351                .values()
3352                .choose(rng)
3353                .map(|state| state.buffer.clone());
3354
3355            if let Some(buffer) = buffer {
3356                buffer.update(cx, |buffer, cx| {
3357                    if rng.random() {
3358                        buffer.randomly_edit(rng, mutation_count, cx);
3359                    } else {
3360                        buffer.randomly_undo_redo(rng, cx);
3361                    }
3362                });
3363            } else {
3364                self.randomly_edit(rng, mutation_count, cx);
3365            }
3366        } else {
3367            self.randomly_edit_excerpts(rng, mutation_count, cx);
3368        }
3369
3370        self.check_invariants(cx);
3371    }
3372
3373    fn check_invariants(&self, cx: &App) {
3374        self.read(cx).check_invariants();
3375    }
3376}
3377
3378impl EventEmitter<Event> for MultiBuffer {}
3379
3380impl MultiBufferSnapshot {
3381    pub fn text(&self) -> String {
3382        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3383            .map(|chunk| chunk.text)
3384            .collect()
3385    }
3386
3387    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3388        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3389            .flat_map(|c| c.chars().rev())
3390    }
3391
3392    fn reversed_chunks_in_range(
3393        &self,
3394        range: Range<MultiBufferOffset>,
3395    ) -> ReversedMultiBufferChunks<'_> {
3396        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3397        cursor.seek(&range.end);
3398        let current_chunks = cursor.region().as_ref().map(|region| {
3399            let start_overshoot = range.start.saturating_sub(region.range.start);
3400            let end_overshoot = range.end - region.range.start;
3401            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3402            let start = region.buffer_range.start + start_overshoot;
3403            region.buffer.reversed_chunks_in_range(start..end)
3404        });
3405        ReversedMultiBufferChunks {
3406            cursor,
3407            current_chunks,
3408            start: range.start,
3409            offset: range.end,
3410        }
3411    }
3412
3413    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3414        let offset = position.to_offset(self);
3415        self.text_for_range(offset..self.len())
3416            .flat_map(|chunk| chunk.chars())
3417    }
3418
3419    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3420        self.chunks(range, false).map(|chunk| chunk.text)
3421    }
3422
3423    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3424        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3425            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3426    }
3427
3428    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3429    where
3430        T: ToOffset,
3431    {
3432        let position = position.to_offset(self);
3433        position == self.clip_offset(position, Bias::Left)
3434            && self
3435                .bytes_in_range(position..self.len())
3436                .flatten()
3437                .copied()
3438                .take(needle.len())
3439                .eq(needle.bytes())
3440    }
3441
3442    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3443        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3444    }
3445
3446    pub fn diff_hunks_in_range<T: ToPoint>(
3447        &self,
3448        range: Range<T>,
3449    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3450        let query_range = range.start.to_point(self)..range.end.to_point(self);
3451        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3452            let diff = self.diffs.get(&buffer.remote_id())?;
3453            let iter = if let Some(main_buffer) = &diff.main_buffer {
3454                let buffer_start = buffer.point_to_offset(buffer_range.start);
3455                let buffer_end = buffer.point_to_offset(buffer_range.end);
3456                itertools::Either::Left(
3457                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3458                        .map(move |hunk| (hunk, buffer, true)),
3459                )
3460            } else {
3461                let buffer_start = buffer.anchor_before(buffer_range.start);
3462                let buffer_end = buffer.anchor_after(buffer_range.end);
3463                itertools::Either::Right(
3464                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3465                        .map(move |hunk| (hunk, buffer, false)),
3466                )
3467            };
3468            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3469                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3470                    return None;
3471                }
3472                let range = if is_inverted {
3473                    hunk.diff_base_byte_range.to_point(&buffer)
3474                } else {
3475                    hunk.range.clone()
3476                };
3477                Some((range, (hunk, is_inverted)))
3478            }))
3479        })
3480        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3481            let buffer_snapshot = excerpt.buffer_snapshot(self);
3482            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3483            {
3484                return None;
3485            }
3486            let end_row = if range.end.column == 0 {
3487                range.end.row
3488            } else {
3489                range.end.row + 1
3490            };
3491
3492            let word_diffs =
3493                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3494                    .then(|| {
3495                        let mut word_diffs = Vec::new();
3496
3497                        if self.show_deleted_hunks || is_inverted {
3498                            let hunk_start_offset = if is_inverted {
3499                                Anchor::in_buffer(
3500                                    excerpt.path_key_index,
3501                                    buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start),
3502                                )
3503                                .to_offset(self)
3504                            } else {
3505                                Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3506                                    .to_offset(self)
3507                            };
3508
3509                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3510                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3511                            }));
3512                        }
3513
3514                        if !is_inverted {
3515                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3516                                Anchor::range_in_buffer(excerpt.path_key_index, diff)
3517                                    .to_offset(self)
3518                            }));
3519                        }
3520                        word_diffs
3521                    })
3522                    .unwrap_or_default();
3523
3524            let buffer_range = if is_inverted {
3525                buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start)
3526                    ..buffer_snapshot.anchor_before(hunk.diff_base_byte_range.end)
3527            } else {
3528                hunk.buffer_range.clone()
3529            };
3530            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3531                DiffHunkStatusKind::Deleted
3532            } else if hunk.diff_base_byte_range.is_empty() {
3533                DiffHunkStatusKind::Added
3534            } else {
3535                DiffHunkStatusKind::Modified
3536            };
3537            Some(MultiBufferDiffHunk {
3538                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3539                buffer_id: buffer_snapshot.remote_id(),
3540                path_key_index: excerpt.path_key_index,
3541                buffer_range,
3542                word_diffs,
3543                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3544                    ..BufferOffset(hunk.diff_base_byte_range.end),
3545                status: DiffHunkStatus {
3546                    kind: status_kind,
3547                    secondary: hunk.secondary_status,
3548                },
3549            })
3550        })
3551    }
3552
3553    fn excerpts_for_range<T: ToOffset>(
3554        &self,
3555        range: Range<T>,
3556    ) -> impl Iterator<Item = &Excerpt> + '_ {
3557        let range = range.start.to_offset(self)..range.end.to_offset(self);
3558        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3559        cursor.seek(&range.start);
3560        std::iter::from_fn(move || {
3561            let region = cursor.region()?;
3562            if region.range.start > range.end
3563                || region.range.start == range.end && region.range.start > range.start
3564            {
3565                return None;
3566            }
3567            let excerpt = region.excerpt;
3568            cursor.next_excerpt_forwards();
3569            Some(excerpt)
3570        })
3571    }
3572
3573    // todo!() repeats ids? seems weird
3574    pub fn buffer_ids_for_range<T: ToOffset>(
3575        &self,
3576        range: Range<T>,
3577    ) -> impl Iterator<Item = BufferId> + '_ {
3578        self.excerpts_for_range(range)
3579            .map(|excerpt| excerpt.buffer_snapshot(self).remote_id())
3580    }
3581
3582    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3583    ///
3584    /// The passed in anchors must be ordered.
3585    pub fn text_anchors_to_visible_anchors(
3586        &self,
3587        anchors: impl IntoIterator<Item = text::Anchor>,
3588    ) -> Vec<Option<Anchor>> {
3589        let anchors = anchors.into_iter();
3590        let mut result = Vec::with_capacity(anchors.size_hint().0);
3591        let mut anchors = anchors.peekable();
3592        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3593        'anchors: while let Some(anchor) = anchors.peek() {
3594            let Some(buffer_id) = anchor.buffer_id else {
3595                anchors.next();
3596                result.push(None);
3597                continue 'anchors;
3598            };
3599            let mut same_buffer_anchors =
3600                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3601
3602            if let Some(buffer) = self.buffers.get(&buffer_id) {
3603                let path = &buffer.path_key;
3604                let Some(mut next) = same_buffer_anchors.next() else {
3605                    continue 'anchors;
3606                };
3607                cursor.seek_forward(path, Bias::Left);
3608                'excerpts: loop {
3609                    let Some(excerpt) = cursor.item() else {
3610                        break;
3611                    };
3612                    if &excerpt.path_key != path {
3613                        break;
3614                    }
3615                    let buffer_snapshot = excerpt.buffer_snapshot(self);
3616
3617                    loop {
3618                        // anchor is before the first excerpt
3619                        if excerpt
3620                            .range
3621                            .context
3622                            .start
3623                            .cmp(&next, &buffer_snapshot)
3624                            .is_gt()
3625                        {
3626                            // so we skip it and try the next anchor
3627                            result.push(None);
3628                            match same_buffer_anchors.next() {
3629                                Some(anchor) => next = anchor,
3630                                None => continue 'anchors,
3631                            }
3632                        // anchor is within the excerpt
3633                        } else if excerpt
3634                            .range
3635                            .context
3636                            .end
3637                            .cmp(&next, &buffer_snapshot)
3638                            .is_ge()
3639                        {
3640                            // record it and all following anchors that are within
3641                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3642                            result.extend(
3643                                same_buffer_anchors
3644                                    .peeking_take_while(|a| {
3645                                        excerpt.range.context.end.cmp(a, &buffer_snapshot).is_ge()
3646                                    })
3647                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3648                            );
3649                            match same_buffer_anchors.next() {
3650                                Some(anchor) => next = anchor,
3651                                None => continue 'anchors,
3652                            }
3653                        // anchor is after the excerpt, try the next one
3654                        } else {
3655                            cursor.next();
3656                            continue 'excerpts;
3657                        }
3658                    }
3659                }
3660                // account for `next`
3661                result.push(None);
3662            }
3663            result.extend(same_buffer_anchors.map(|_| None));
3664        }
3665
3666        result
3667    }
3668
3669    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3670        &self,
3671        ranges: impl Iterator<Item = Range<T>>,
3672    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>)> {
3673        ranges.flat_map(|range| {
3674            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3675                .into_iter()
3676        })
3677    }
3678
3679    // todo!() can we make this not RangeBounds
3680    pub fn range_to_buffer_ranges<R, T>(
3681        &self,
3682        range: R,
3683    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>)>
3684    where
3685        R: RangeBounds<T>,
3686        T: ToOffset,
3687    {
3688        self.range_to_buffer_ranges_with_context(range)
3689            .into_iter()
3690            .map(|(buffer, range, _context)| (buffer, range))
3691            .collect()
3692    }
3693
3694    pub fn range_to_buffer_ranges_with_context<R, T>(
3695        &self,
3696        range: R,
3697    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)>
3698    where
3699        R: RangeBounds<T>,
3700        T: ToOffset,
3701    {
3702        let start = match range.start_bound() {
3703            Bound::Included(start) => start.to_offset(self),
3704            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3705            Bound::Unbounded => MultiBufferOffset::ZERO,
3706        };
3707        let end_bound = match range.end_bound() {
3708            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3709            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3710            Bound::Unbounded => Bound::Unbounded,
3711        };
3712        let bounds = (Bound::Included(start), end_bound);
3713
3714        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3715        cursor.seek(&start);
3716
3717        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)> =
3718            Vec::new();
3719        let mut last_excerpt = None;
3720        while let Some(region) = cursor.region() {
3721            let dominated_by_end_bound = match end_bound {
3722                Bound::Included(end) => region.range.start > end,
3723                Bound::Excluded(end) => region.range.start >= end,
3724                Bound::Unbounded => false,
3725            };
3726            if dominated_by_end_bound {
3727                break;
3728            }
3729            if region.is_main_buffer {
3730                let start_overshoot = start.saturating_sub(region.range.start);
3731                let end_offset = match end_bound {
3732                    Bound::Included(end) | Bound::Excluded(end) => end,
3733                    Bound::Unbounded => region.range.end,
3734                };
3735                let end_overshoot = end_offset.saturating_sub(region.range.start);
3736                let start = region
3737                    .buffer_range
3738                    .end
3739                    .min(region.buffer_range.start + start_overshoot);
3740                let end = region
3741                    .buffer_range
3742                    .end
3743                    .min(region.buffer_range.start + end_overshoot);
3744                let context = region.excerpt.range.context.clone();
3745                if last_excerpt
3746                    .as_ref()
3747                    .is_some_and(|prev_excerpt| prev_excerpt == &region.excerpt.info())
3748                    && let Some(prev) = result
3749                        .last_mut()
3750                        .filter(|(_, prev_range, _)| prev_range.end == start)
3751                {
3752                    prev.1.end = end;
3753                } else {
3754                    result.push((region.buffer, start..end, context));
3755                    // todo!() is there a better way to do this?
3756                    last_excerpt = Some(region.excerpt.info())
3757                }
3758            }
3759            cursor.next();
3760        }
3761
3762        if let Some(excerpt) = cursor.excerpt() {
3763            let dominated_by_prev_excerpt =
3764                last_excerpt.is_some_and(|last_excerpt| last_excerpt == excerpt.info());
3765            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3766                let excerpt_position = self.len();
3767                let buffer_snapshot = excerpt.buffer_snapshot(self);
3768                if bounds.contains(&excerpt_position) {
3769                    let buffer_offset =
3770                        BufferOffset(excerpt.range.context.start.to_offset(buffer_snapshot));
3771                    let context = excerpt.range.context.clone();
3772                    result.push((buffer_snapshot, buffer_offset..buffer_offset, context));
3773                }
3774            }
3775        }
3776
3777        result
3778    }
3779
3780    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3781        &self,
3782        range: Range<T>,
3783    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, Option<Anchor>)> + '_ {
3784        let start = range.start.to_offset(self);
3785        let end = range.end.to_offset(self);
3786
3787        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3788        cursor.seek(&start);
3789
3790        std::iter::from_fn(move || {
3791            let region = cursor.region()?;
3792            if region.range.start > end {
3793                return None;
3794            }
3795            let start_overshoot = start.saturating_sub(region.range.start);
3796            let end_overshoot = end.saturating_sub(region.range.start);
3797            let start = region
3798                .buffer_range
3799                .end
3800                .min(region.buffer_range.start + start_overshoot);
3801            let end = region
3802                .buffer_range
3803                .end
3804                .min(region.buffer_range.start + end_overshoot);
3805
3806            let deleted_hunk_anchor = if region.is_main_buffer {
3807                None
3808            } else {
3809                Some(self.anchor_before(region.range.start))
3810            };
3811            let result = (region.buffer, start..end, deleted_hunk_anchor);
3812            cursor.next();
3813            Some(result)
3814        })
3815    }
3816
3817    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3818    /// coordinates.
3819    ///
3820    /// The given callback will be called for every excerpt intersecting the given range. It will
3821    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3822    /// The callback should return an iterator of metadata items from that buffer, each paired
3823    /// with a buffer range.
3824    ///
3825    /// The returned iterator yields each of these metadata items, paired with its range in
3826    /// multi-buffer coordinates.
3827    fn lift_buffer_metadata<'a, MBD, M, I>(
3828        &'a self,
3829        query_range: Range<MBD>,
3830        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3831    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3832    where
3833        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3834        MBD: MultiBufferDimension
3835            + Ord
3836            + Sub<Output = MBD::TextDimension>
3837            + ops::Add<MBD::TextDimension, Output = MBD>
3838            + ops::AddAssign<MBD::TextDimension>,
3839        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3840            + ops::Add<Output = MBD::TextDimension>
3841            + AddAssign<MBD::TextDimension>
3842            + Ord,
3843    {
3844        let mut current_excerpt_metadata: Option<(ExcerptAnchor, I)> = None;
3845        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3846
3847        // Find the excerpt and buffer offset where the given range ends.
3848        cursor.seek(&query_range.end);
3849        let mut range_end = None;
3850        while let Some(region) = cursor.region() {
3851            if region.is_main_buffer {
3852                let mut buffer_end = region.buffer_range.start;
3853                let overshoot = if query_range.end > region.range.start {
3854                    query_range.end - region.range.start
3855                } else {
3856                    <MBD::TextDimension>::default()
3857                };
3858                buffer_end = buffer_end + overshoot;
3859                range_end = Some((region.excerpt.end_anchor(), buffer_end));
3860                break;
3861            }
3862            cursor.next();
3863        }
3864
3865        cursor.seek(&query_range.start);
3866
3867        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3868            && region.range.start > MBD::default()
3869        {
3870            cursor.prev()
3871        } else if let Some(region) = cursor.region()
3872            && region.is_main_buffer
3873            && region.diff_hunk_status.is_some()
3874        {
3875            cursor.prev();
3876            if cursor.region().is_none_or(|region| region.is_main_buffer) {
3877                cursor.next();
3878            }
3879        }
3880
3881        iter::from_fn(move || {
3882            loop {
3883                let excerpt = cursor.excerpt()?;
3884                let buffer_snapshot = excerpt.buffer_snapshot(self);
3885
3886                // If we have already retrieved metadata for this excerpt, continue to use it.
3887                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3888                    .as_mut()
3889                    .filter(|(excerpt_anchor, _)| excerpt_anchor == &excerpt.end_anchor())
3890                {
3891                    Some(metadata)
3892                }
3893                // Otherwise, compute the intersection of the input range with the excerpt's range,
3894                // and retrieve the metadata for the resulting range.
3895                else {
3896                    let region = cursor.region()?;
3897                    let mut buffer_start;
3898                    if region.is_main_buffer {
3899                        buffer_start = region.buffer_range.start;
3900                        if query_range.start > region.range.start {
3901                            let overshoot = query_range.start - region.range.start;
3902                            buffer_start = buffer_start + overshoot;
3903                        }
3904                        buffer_start = buffer_start.min(region.buffer_range.end);
3905                    } else {
3906                        buffer_start = cursor.main_buffer_position()?;
3907                    };
3908                    let mut buffer_end = excerpt
3909                        .range
3910                        .context
3911                        .end
3912                        .summary::<MBD::TextDimension>(&buffer_snapshot);
3913                    if let Some((end_excerpt, end_buffer_offset)) = range_end
3914                        && excerpt.end_anchor() == end_excerpt
3915                    {
3916                        buffer_end = buffer_end.min(end_buffer_offset);
3917                    }
3918
3919                    get_buffer_metadata(&buffer_snapshot, buffer_start..buffer_end).map(
3920                        |iterator| {
3921                            &mut current_excerpt_metadata
3922                                .insert((excerpt.end_anchor(), iterator))
3923                                .1
3924                        },
3925                    )
3926                };
3927
3928                // Visit each metadata item.
3929                if let Some((metadata_buffer_range, metadata)) =
3930                    metadata_iter.and_then(Iterator::next)
3931                {
3932                    // Find the multibuffer regions that contain the start and end of
3933                    // the metadata item's range.
3934                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3935                        while let Some(region) = cursor.region() {
3936                            if (region.is_main_buffer
3937                                && (region.buffer_range.end >= metadata_buffer_range.start
3938                                    || cursor.is_at_end_of_excerpt()))
3939                                || (!region.is_main_buffer
3940                                    && region.buffer_range.start == metadata_buffer_range.start)
3941                            {
3942                                break;
3943                            }
3944                            cursor.next();
3945                        }
3946                    }
3947                    let start_region = cursor.region()?.clone();
3948                    while let Some(region) = cursor.region() {
3949                        if region.is_main_buffer
3950                            && (region.buffer_range.end > metadata_buffer_range.end
3951                                || cursor.is_at_end_of_excerpt())
3952                        {
3953                            break;
3954                        }
3955                        cursor.next();
3956                    }
3957                    let end_region = cursor.region();
3958
3959                    // Convert the metadata item's range into multibuffer coordinates.
3960                    let mut start_position = start_region.range.start;
3961                    let region_buffer_start = start_region.buffer_range.start;
3962                    if start_region.is_main_buffer
3963                        && metadata_buffer_range.start > region_buffer_start
3964                    {
3965                        start_position =
3966                            start_position + (metadata_buffer_range.start - region_buffer_start);
3967                        start_position = start_position.min(start_region.range.end);
3968                    }
3969
3970                    let mut end_position = self.max_position();
3971                    if let Some(end_region) = &end_region {
3972                        end_position = end_region.range.start;
3973                        debug_assert!(end_region.is_main_buffer);
3974                        let region_buffer_start = end_region.buffer_range.start;
3975                        if metadata_buffer_range.end > region_buffer_start {
3976                            end_position =
3977                                end_position + (metadata_buffer_range.end - region_buffer_start);
3978                        }
3979                        end_position = end_position.min(end_region.range.end);
3980                    }
3981
3982                    if start_position <= query_range.end && end_position >= query_range.start {
3983                        return Some((start_position..end_position, metadata, excerpt));
3984                    }
3985                }
3986                // When there are no more metadata items for this excerpt, move to the next excerpt.
3987                else {
3988                    current_excerpt_metadata.take();
3989                    if let Some((end_excerpt, _)) = range_end
3990                        && excerpt.end_anchor() == end_excerpt
3991                    {
3992                        return None;
3993                    }
3994                    cursor.next_excerpt_forwards();
3995                }
3996            }
3997        })
3998    }
3999
4000    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4001        let offset = position.to_offset(self);
4002
4003        let mut cursor = self
4004            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4005            );
4006        cursor.seek(&DimensionPair {
4007            key: offset,
4008            value: None,
4009        });
4010        cursor.seek_to_start_of_current_excerpt();
4011        let excerpt = cursor.excerpt()?;
4012
4013        let buffer = excerpt.buffer_snapshot(self);
4014        let excerpt_start = excerpt.range.context.start.to_offset(buffer);
4015        let excerpt_end = excerpt.range.context.end.to_offset(buffer);
4016        let current_position = match self.anchor_before(offset) {
4017            Anchor::Min => 0,
4018            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor.text_anchor().to_offset(buffer),
4019            Anchor::Max => unreachable!(),
4020        };
4021
4022        if let Some(diff) = self.diffs.get(&buffer.remote_id()) {
4023            if let Some(main_buffer) = &diff.main_buffer {
4024                for hunk in diff
4025                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4026                {
4027                    if hunk.diff_base_byte_range.end >= current_position {
4028                        continue;
4029                    }
4030                    let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
4031                    let start =
4032                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4033                    return Some(MultiBufferRow(start.row));
4034                }
4035            } else {
4036                let excerpt_end = buffer.anchor_before(excerpt_end.min(current_position));
4037                for hunk in diff
4038                    .hunks_intersecting_range_rev(excerpt.range.context.start..excerpt_end, buffer)
4039                {
4040                    let hunk_end = hunk.buffer_range.end.to_offset(buffer);
4041                    if hunk_end >= current_position {
4042                        continue;
4043                    }
4044                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4045                        .to_point(self);
4046                    return Some(MultiBufferRow(start.row));
4047                }
4048            }
4049        }
4050
4051        loop {
4052            cursor.prev_excerpt();
4053            let excerpt = cursor.excerpt()?;
4054
4055            let buffer = excerpt.buffer_snapshot(self);
4056            let Some(diff) = self.diffs.get(&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(buffer),
4063                        main_buffer,
4064                    )
4065                    .next()
4066                else {
4067                    continue;
4068                };
4069                let hunk_start = 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(), 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<&BufferSnapshot> {
4160        if self.singleton {
4161            self.excerpts.first().map(|e| e.buffer_snapshot(self))
4162        } else {
4163            None
4164        }
4165    }
4166
4167    pub fn len(&self) -> MultiBufferOffset {
4168        self.diff_transforms.summary().output.len
4169    }
4170
4171    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4172        MBD::from_summary(&self.text_summary())
4173    }
4174
4175    pub fn is_empty(&self) -> bool {
4176        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4177    }
4178
4179    pub fn widest_line_number(&self) -> u32 {
4180        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4181        self.excerpts.summary().widest_line_number + 1
4182    }
4183
4184    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4185        let range = range.start.to_offset(self)..range.end.to_offset(self);
4186        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4187        excerpts.seek(&range.start);
4188
4189        let mut chunk;
4190        let mut has_trailing_newline;
4191        let excerpt_bytes;
4192        if let Some(region) = excerpts.region() {
4193            let mut bytes = region.buffer.bytes_in_range(
4194                region.buffer_range.start + (range.start - region.range.start)
4195                    ..(region.buffer_range.start + (range.end - region.range.start))
4196                        .min(region.buffer_range.end),
4197            );
4198            chunk = bytes.next().unwrap_or(&[][..]);
4199            excerpt_bytes = Some(bytes);
4200            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4201            if chunk.is_empty() && has_trailing_newline {
4202                chunk = b"\n";
4203                has_trailing_newline = false;
4204            }
4205        } else {
4206            chunk = &[][..];
4207            excerpt_bytes = None;
4208            has_trailing_newline = false;
4209        };
4210
4211        MultiBufferBytes {
4212            range,
4213            cursor: excerpts,
4214            excerpt_bytes,
4215            has_trailing_newline,
4216            chunk,
4217        }
4218    }
4219
4220    pub fn reversed_bytes_in_range<T: ToOffset>(
4221        &self,
4222        range: Range<T>,
4223    ) -> ReversedMultiBufferBytes<'_> {
4224        let range = range.start.to_offset(self)..range.end.to_offset(self);
4225        let mut chunks = self.reversed_chunks_in_range(range.clone());
4226        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4227        ReversedMultiBufferBytes {
4228            range,
4229            chunks,
4230            chunk,
4231        }
4232    }
4233
4234    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4235        dbg!(self.diff_transforms.is_empty());
4236        let mut cursor = self.cursor::<Point, Point>();
4237        cursor.seek(&Point::new(start_row.0, 0));
4238        let mut result = MultiBufferRows {
4239            point: Point::new(0, 0),
4240            is_empty: self.excerpts.is_empty(),
4241            is_singleton: self.is_singleton(),
4242            cursor,
4243        };
4244        result.seek(start_row);
4245        result
4246    }
4247
4248    pub fn chunks<T: ToOffset>(
4249        &self,
4250        range: Range<T>,
4251        language_aware: bool,
4252    ) -> MultiBufferChunks<'_> {
4253        let mut chunks = MultiBufferChunks {
4254            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4255                ..ExcerptDimension(MultiBufferOffset::ZERO),
4256            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4257            excerpts: self.excerpts.cursor(()),
4258            diff_transforms: self.diff_transforms.cursor(()),
4259            diff_base_chunks: None,
4260            excerpt_chunks: None,
4261            buffer_chunk: None,
4262            language_aware,
4263            snapshot: self,
4264        };
4265        let range = range.start.to_offset(self)..range.end.to_offset(self);
4266        chunks.seek(range);
4267        chunks
4268    }
4269
4270    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4271        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4272    }
4273
4274    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4275        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4276    }
4277
4278    pub fn clip_offset_utf16(
4279        &self,
4280        offset: MultiBufferOffsetUtf16,
4281        bias: Bias,
4282    ) -> MultiBufferOffsetUtf16 {
4283        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4284    }
4285
4286    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4287        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4288            buffer.clip_point_utf16(Unclipped(point), bias)
4289        })
4290    }
4291
4292    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4293        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4294    }
4295
4296    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4297        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4298    }
4299
4300    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4301        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4302    }
4303
4304    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4305        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4306    }
4307
4308    #[instrument(skip_all)]
4309    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4310        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4311    }
4312
4313    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4314        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4315    }
4316
4317    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4318        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4319    }
4320
4321    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4322        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4323    }
4324
4325    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4326        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4327    }
4328
4329    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4330        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4331    }
4332
4333    fn clip_dimension<MBD, BD>(
4334        &self,
4335        position: MBD,
4336        bias: Bias,
4337        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4338    ) -> MBD
4339    where
4340        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4341        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4342    {
4343        let mut cursor = self.cursor::<MBD, BD>();
4344        cursor.seek(&position);
4345        if let Some(region) = cursor.region() {
4346            if position >= region.range.end {
4347                return region.range.end;
4348            }
4349            let overshoot = position - region.range.start;
4350            let mut buffer_position = region.buffer_range.start;
4351            buffer_position += overshoot;
4352            let clipped_buffer_position =
4353                clip_buffer_position(region.buffer, buffer_position, bias);
4354            let mut position = region.range.start;
4355            position += clipped_buffer_position - region.buffer_range.start;
4356            position
4357        } else {
4358            self.max_position()
4359        }
4360    }
4361
4362    #[instrument(skip_all)]
4363    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4364        &self,
4365        key: MBR1,
4366        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4367    ) -> MBR2
4368    where
4369        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4370        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4371        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4372        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4373    {
4374        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4375        cursor.seek(&DimensionPair { key, value: None });
4376        if let Some(region) = cursor.region() {
4377            if key >= region.range.end.key {
4378                return region.range.end.value.unwrap();
4379            }
4380            let start_key = region.range.start.key;
4381            let start_value = region.range.start.value.unwrap();
4382            let buffer_start_key = region.buffer_range.start.key;
4383            let buffer_start_value = region.buffer_range.start.value.unwrap();
4384            let mut buffer_key = buffer_start_key;
4385            buffer_key += key - start_key;
4386            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4387            let mut result = start_value;
4388            result += buffer_value - buffer_start_value;
4389            result
4390        } else {
4391            self.max_position()
4392        }
4393    }
4394
4395    pub fn point_to_buffer_offset<T: ToOffset>(
4396        &self,
4397        point: T,
4398    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4399        let offset = point.to_offset(self);
4400        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4401        cursor.seek(&offset);
4402        let region = cursor.region()?;
4403        let overshoot = offset - region.range.start;
4404        let buffer_offset = region.buffer_range.start + overshoot;
4405        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4406            && region.has_trailing_newline
4407            && !region.is_main_buffer
4408        {
4409            let main_buffer_position = cursor.main_buffer_position()?;
4410            let buffer_snapshot = cursor.excerpt()?.buffer_snapshot(self);
4411            return Some((buffer_snapshot, main_buffer_position));
4412        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4413            return None;
4414        }
4415        Some((region.buffer, buffer_offset))
4416    }
4417
4418    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4419        let mut cursor = self.cursor::<Point, Point>();
4420        cursor.seek(&point);
4421        let region = cursor.region()?;
4422        let overshoot = point - region.range.start;
4423        let buffer_point = region.buffer_range.start + overshoot;
4424        let excerpt = cursor.excerpt()?;
4425        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4426            && region.has_trailing_newline
4427            && !region.is_main_buffer
4428        {
4429            return Some((
4430                &excerpt.buffer_snapshot(self),
4431                cursor.main_buffer_position()?,
4432            ));
4433        } else if buffer_point > region.buffer.max_point() {
4434            return None;
4435        }
4436        Some((region.buffer, buffer_point))
4437    }
4438
4439    pub fn suggested_indents(
4440        &self,
4441        rows: impl IntoIterator<Item = u32>,
4442        cx: &App,
4443    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4444        let mut result = BTreeMap::new();
4445        self.suggested_indents_callback(
4446            rows,
4447            &mut |row, indent| {
4448                result.insert(row, indent);
4449                ControlFlow::Continue(())
4450            },
4451            cx,
4452        );
4453        result
4454    }
4455
4456    // move this to be a generator once those are a thing
4457    pub fn suggested_indents_callback(
4458        &self,
4459        rows: impl IntoIterator<Item = u32>,
4460        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4461        cx: &App,
4462    ) {
4463        let mut rows_for_excerpt = Vec::new();
4464        let mut cursor = self.cursor::<Point, Point>();
4465        let mut rows = rows.into_iter().peekable();
4466        let mut prev_row = u32::MAX;
4467        let mut prev_language_indent_size = IndentSize::default();
4468
4469        while let Some(row) = rows.next() {
4470            cursor.seek(&Point::new(row, 0));
4471            let Some(region) = cursor.region() else {
4472                continue;
4473            };
4474
4475            // Retrieve the language and indent size once for each disjoint region being indented.
4476            let single_indent_size = if row.saturating_sub(1) == prev_row {
4477                prev_language_indent_size
4478            } else {
4479                region
4480                    .buffer
4481                    .language_indent_size_at(Point::new(row, 0), cx)
4482            };
4483            prev_language_indent_size = single_indent_size;
4484            prev_row = row;
4485
4486            let start_buffer_row = region.buffer_range.start.row;
4487            let start_multibuffer_row = region.range.start.row;
4488            let end_multibuffer_row = region.range.end.row;
4489
4490            rows_for_excerpt.push(row);
4491            while let Some(next_row) = rows.peek().copied() {
4492                if end_multibuffer_row > next_row {
4493                    rows_for_excerpt.push(next_row);
4494                    rows.next();
4495                } else {
4496                    break;
4497                }
4498            }
4499
4500            let buffer_rows = rows_for_excerpt
4501                .drain(..)
4502                .map(|row| start_buffer_row + row - start_multibuffer_row);
4503            let buffer_indents = region
4504                .buffer
4505                .suggested_indents(buffer_rows, single_indent_size);
4506            for (row, indent) in buffer_indents {
4507                if cb(
4508                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4509                    indent,
4510                )
4511                .is_break()
4512                {
4513                    return;
4514                }
4515            }
4516        }
4517    }
4518
4519    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4520        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4521            let mut size = buffer.indent_size_for_line(range.start.row);
4522            size.len = size
4523                .len
4524                .min(range.end.column)
4525                .saturating_sub(range.start.column);
4526            size
4527        } else {
4528            IndentSize::spaces(0)
4529        }
4530    }
4531
4532    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4533        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4534            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4535        } else {
4536            LineIndent::spaces(0)
4537        }
4538    }
4539
4540    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4541        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4542
4543        if self.language_settings(cx).extend_comment_on_newline
4544            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4545        {
4546            let delimiters = language_scope.line_comment_prefixes();
4547            for delimiter in delimiters {
4548                if *self
4549                    .chars_at(Point::new(row.0, indent.len() as u32))
4550                    .take(delimiter.chars().count())
4551                    .collect::<String>()
4552                    .as_str()
4553                    == **delimiter
4554                {
4555                    indent.push_str(delimiter);
4556                    break;
4557                }
4558            }
4559        }
4560
4561        indent
4562    }
4563
4564    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4565    where
4566        T: ToOffset,
4567    {
4568        for char in self.reversed_chars_at(position) {
4569            if !char.is_whitespace() {
4570                return false;
4571            }
4572            if char == '\n' {
4573                return true;
4574            }
4575        }
4576        true
4577    }
4578
4579    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4580        while row.0 > 0 {
4581            row.0 -= 1;
4582            if !self.is_line_blank(row) {
4583                return Some(row);
4584            }
4585        }
4586        None
4587    }
4588
4589    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4590        if let Some((_, range)) = self.buffer_line_for_row(row) {
4591            range.end.column - range.start.column
4592        } else {
4593            0
4594        }
4595    }
4596
4597    pub fn buffer_line_for_row(
4598        &self,
4599        row: MultiBufferRow,
4600    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4601        let mut cursor = self.cursor::<Point, Point>();
4602        let point = Point::new(row.0, 0);
4603        cursor.seek(&point);
4604        let region = cursor.region()?;
4605        let overshoot = point.min(region.range.end) - region.range.start;
4606        let buffer_point = region.buffer_range.start + overshoot;
4607        if buffer_point.row > region.buffer_range.end.row {
4608            return None;
4609        }
4610        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4611        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4612            .min(region.buffer_range.end);
4613        Some((region.buffer, line_start..line_end))
4614    }
4615
4616    pub fn max_point(&self) -> Point {
4617        self.text_summary().lines
4618    }
4619
4620    pub fn max_row(&self) -> MultiBufferRow {
4621        MultiBufferRow(self.text_summary().lines.row)
4622    }
4623
4624    pub fn text_summary(&self) -> MBTextSummary {
4625        self.diff_transforms.summary().output
4626    }
4627
4628    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4629    where
4630        MBD: MultiBufferDimension + AddAssign,
4631        O: ToOffset,
4632    {
4633        let range = range.start.to_offset(self)..range.end.to_offset(self);
4634        let mut cursor = self
4635            .diff_transforms
4636            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4637        cursor.seek(&range.start, Bias::Right);
4638
4639        let Some(first_transform) = cursor.item() else {
4640            return MBD::from_summary(&MBTextSummary::default());
4641        };
4642
4643        let diff_transform_start = cursor.start().0;
4644        let diff_transform_end = cursor.end().0;
4645        let diff_start = range.start;
4646        let start_overshoot = diff_start - diff_transform_start;
4647        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4648
4649        let mut result = match first_transform {
4650            DiffTransform::BufferContent { .. } => {
4651                let excerpt_start = cursor.start().1 + start_overshoot;
4652                let excerpt_end = cursor.start().1 + end_overshoot;
4653                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4654            }
4655            DiffTransform::DeletedHunk {
4656                buffer_id,
4657                base_text_byte_range,
4658                has_trailing_newline,
4659                ..
4660            } => {
4661                let buffer_start = base_text_byte_range.start + start_overshoot;
4662                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4663                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4664                    panic!("{:?} is in non-existent deleted hunk", range.start)
4665                };
4666
4667                let include_trailing_newline =
4668                    *has_trailing_newline && range.end >= diff_transform_end;
4669                if include_trailing_newline {
4670                    buffer_end -= 1;
4671                }
4672
4673                let mut summary = base_text
4674                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4675
4676                if include_trailing_newline {
4677                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4678                        &TextSummary::newline(),
4679                    ))
4680                }
4681
4682                let mut result = MBD::default();
4683                result.add_text_dim(&summary);
4684                result
4685            }
4686        };
4687        if range.end < diff_transform_end {
4688            return result;
4689        }
4690
4691        cursor.next();
4692        result.add_mb_text_summary(
4693            &cursor
4694                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4695                .0,
4696        );
4697
4698        let Some(last_transform) = cursor.item() else {
4699            return result;
4700        };
4701
4702        let overshoot = range.end - cursor.start().0;
4703        let suffix = match last_transform {
4704            DiffTransform::BufferContent { .. } => {
4705                let end = cursor.start().1 + overshoot;
4706                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4707            }
4708            DiffTransform::DeletedHunk {
4709                base_text_byte_range,
4710                buffer_id,
4711                has_trailing_newline,
4712                ..
4713            } => {
4714                let buffer_end = base_text_byte_range.start + overshoot;
4715                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4716                    panic!("{:?} is in non-existent deleted hunk", range.end)
4717                };
4718
4719                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4720                    base_text_byte_range.start..buffer_end,
4721                );
4722                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4723                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4724                        &TextSummary::from("\n"),
4725                    ))
4726                }
4727
4728                let mut result = MBD::default();
4729                result.add_text_dim(&suffix);
4730                result
4731            }
4732        };
4733
4734        result += suffix;
4735        result
4736    }
4737
4738    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4739    where
4740        MBD: MultiBufferDimension + AddAssign,
4741    {
4742        let mut summary = MBD::default();
4743        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4744        cursor.seek(&range.start, Bias::Right);
4745        if let Some(excerpt) = cursor.item() {
4746            let buffer_snapshot = excerpt.buffer_snapshot(self);
4747            let mut end_before_newline = cursor.end();
4748            if excerpt.has_trailing_newline {
4749                end_before_newline -= 1;
4750            }
4751
4752            let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4753            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4754            let end_in_excerpt =
4755                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4756            summary.add_text_dim(
4757                &buffer_snapshot.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                let buffer_snapshot = excerpt.buffer_snapshot(self);
4775                range.end = cmp::max(*cursor.start(), range.end);
4776
4777                let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4778                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4779                summary.add_text_dim(
4780                    &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4781                        excerpt_start..end_in_excerpt,
4782                    ),
4783                );
4784            }
4785        }
4786
4787        summary
4788    }
4789
4790    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4791    where
4792        MBD: MultiBufferDimension
4793            + Ord
4794            + Sub<Output = MBD::TextDimension>
4795            + Sub<MBD::TextDimension, Output = MBD>
4796            + AddAssign<MBD::TextDimension>
4797            + Add<MBD::TextDimension, Output = MBD>,
4798        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4799    {
4800        let target = anchor.seek_target(self);
4801        let anchor = match anchor {
4802            Anchor::Min => {
4803                return MBD::default();
4804            }
4805            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4806            Anchor::Max => {
4807                return MBD::from_summary(&self.text_summary());
4808            }
4809        };
4810
4811        let (start, _, item) = self
4812            .excerpts
4813            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4814        let start = MBD::from_summary(&start.text);
4815
4816        let excerpt_start_position = ExcerptDimension(start);
4817        if self.diff_transforms.is_empty() {
4818            if let Some(excerpt) = item {
4819                if !excerpt.contains(anchor, self) {
4820                    return excerpt_start_position.0;
4821                }
4822                let buffer_snapshot = excerpt.buffer_snapshot(self);
4823                let excerpt_buffer_start = excerpt
4824                    .range
4825                    .context
4826                    .start
4827                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4828                let excerpt_buffer_end = excerpt
4829                    .range
4830                    .context
4831                    .end
4832                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4833                let buffer_summary = anchor
4834                    .text_anchor()
4835                    .summary::<MBD::TextDimension>(&buffer_snapshot);
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, self) {
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 buffer_snapshot = excerpt.buffer_snapshot(self);
4861                let excerpt_buffer_start = excerpt
4862                    .range
4863                    .context
4864                    .start
4865                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4866                let excerpt_buffer_end = excerpt
4867                    .range
4868                    .context
4869                    .end
4870                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4871                let buffer_summary = anchor
4872                    .text_anchor()
4873                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4874                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4875                let mut position = excerpt_start_position;
4876                if summary > excerpt_buffer_start {
4877                    position += summary - excerpt_buffer_start;
4878                }
4879
4880                if diff_transforms_cursor.start().0 < position {
4881                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
4882                }
4883                self.summary_for_anchor_with_excerpt_position(
4884                    *anchor,
4885                    position,
4886                    &mut diff_transforms_cursor,
4887                    &buffer_snapshot,
4888                )
4889            } else {
4890                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
4891                self.summary_for_excerpt_position_without_hunks(
4892                    Bias::Right,
4893                    excerpt_start_position,
4894                    &mut diff_transforms_cursor,
4895                )
4896            }
4897        }
4898    }
4899
4900    /// Maps an anchor's excerpt-space position to its output-space position by
4901    /// walking the diff transforms. The cursor is shared across consecutive
4902    /// calls, so it may already be partway through the transform list.
4903    fn summary_for_anchor_with_excerpt_position<MBD>(
4904        &self,
4905        anchor: ExcerptAnchor,
4906        excerpt_position: ExcerptDimension<MBD>,
4907        diff_transforms: &mut Cursor<
4908            DiffTransform,
4909            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4910        >,
4911        excerpt_buffer: &text::BufferSnapshot,
4912    ) -> MBD
4913    where
4914        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4915    {
4916        loop {
4917            let transform_end_position = diff_transforms.end().0;
4918            let item = diff_transforms.item();
4919            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4920
4921            // A right-biased anchor at a transform boundary belongs to the
4922            // *next* transform, so advance past the current one.
4923            if anchor.bias == Bias::Right && at_transform_end {
4924                diff_transforms.next();
4925                continue;
4926            }
4927
4928            let mut position = diff_transforms.start().1;
4929            match item {
4930                Some(DiffTransform::DeletedHunk {
4931                    buffer_id,
4932                    base_text_byte_range,
4933                    hunk_info,
4934                    ..
4935                }) => {
4936                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
4937                        && let Some(base_text) =
4938                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4939                        && diff_base_anchor.is_valid(&base_text)
4940                    {
4941                        // The anchor carries a diff-base position — resolve it
4942                        // to a location inside the deleted hunk.
4943                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4944                        if base_text_offset >= base_text_byte_range.start
4945                            && base_text_offset <= base_text_byte_range.end
4946                        {
4947                            let position_in_hunk = base_text
4948                                .text_summary_for_range::<MBD::TextDimension, _>(
4949                                    base_text_byte_range.start..base_text_offset,
4950                                );
4951                            position.0.add_text_dim(&position_in_hunk);
4952                        } else if at_transform_end {
4953                            // diff_base offset falls outside this hunk's range;
4954                            // advance to see if the next transform is a better fit.
4955                            diff_transforms.next();
4956                            continue;
4957                        }
4958                    } else if at_transform_end
4959                        && anchor
4960                            .text_anchor()
4961                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
4962                            .is_gt()
4963                    {
4964                        // The anchor has no (valid) diff-base position, so it
4965                        // belongs in the buffer content, not in the deleted
4966                        // hunk. However, after an edit deletes the text between
4967                        // the hunk boundary and this anchor, both resolve to
4968                        // the same excerpt_position—landing us here on the
4969                        // DeletedHunk left behind by the shared cursor. Use the
4970                        // CRDT ordering to detect that the anchor is strictly
4971                        // *past* the hunk boundary and skip to the following
4972                        // BufferContent.
4973                        diff_transforms.next();
4974                        continue;
4975                    }
4976                }
4977                _ => {
4978                    // On a BufferContent (or no transform). If the anchor
4979                    // carries a diff_base_anchor it needs a DeletedHunk, so
4980                    // advance to find one.
4981                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4982                        diff_transforms.next();
4983                        continue;
4984                    }
4985                    let overshoot = excerpt_position - diff_transforms.start().0;
4986                    position += overshoot;
4987                }
4988            }
4989
4990            return position.0;
4991        }
4992    }
4993
4994    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
4995    fn summary_for_excerpt_position_without_hunks<MBD>(
4996        &self,
4997        bias: Bias,
4998        excerpt_position: ExcerptDimension<MBD>,
4999        diff_transforms: &mut Cursor<
5000            DiffTransform,
5001            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5002        >,
5003    ) -> MBD
5004    where
5005        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5006    {
5007        loop {
5008            let transform_end_position = diff_transforms.end().0;
5009            let item = diff_transforms.item();
5010            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5011
5012            // A right-biased anchor at a transform boundary belongs to the
5013            // *next* transform, so advance past the current one.
5014            if bias == Bias::Right && at_transform_end {
5015                diff_transforms.next();
5016                continue;
5017            }
5018
5019            let mut position = diff_transforms.start().1;
5020            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5021                let overshoot = excerpt_position - diff_transforms.start().0;
5022                position += overshoot;
5023            }
5024
5025            return position.0;
5026        }
5027    }
5028
5029    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5030        let anchor = match anchor {
5031            Anchor::Min => return ExcerptOffset::default(),
5032            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5033            Anchor::Max => return self.excerpts.summary().len(),
5034        };
5035        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5036        let target = anchor.seek_target(self);
5037
5038        cursor.seek(&target, Bias::Left);
5039
5040        let mut position = cursor.start().len();
5041        if let Some(excerpt) = cursor.item()
5042            && excerpt.contains(anchor, self)
5043        {
5044            let buffer_snapshot = excerpt.buffer_snapshot(self);
5045            let excerpt_buffer_start =
5046                buffer_snapshot.offset_for_anchor(&excerpt.range.context.start);
5047            let excerpt_buffer_end = buffer_snapshot.offset_for_anchor(&excerpt.range.context.end);
5048            let buffer_position = cmp::min(
5049                excerpt_buffer_end,
5050                buffer_snapshot.offset_for_anchor(&anchor.text_anchor()),
5051            );
5052            if buffer_position > excerpt_buffer_start {
5053                position += buffer_position - excerpt_buffer_start;
5054            }
5055        }
5056        position
5057    }
5058
5059    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5060    where
5061        MBD: MultiBufferDimension
5062            + Ord
5063            + Sub<Output = MBD::TextDimension>
5064            + AddAssign<MBD::TextDimension>,
5065        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5066        I: 'a + IntoIterator<Item = &'a Anchor>,
5067    {
5068        let mut anchors = anchors.into_iter().peekable();
5069        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5070        let mut diff_transforms_cursor = self
5071            .diff_transforms
5072            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5073        diff_transforms_cursor.next();
5074
5075        let mut summaries = Vec::new();
5076        while let Some(anchor) = anchors.peek() {
5077            let target = anchor.seek_target(self);
5078            let excerpt_anchor = match anchor {
5079                Anchor::Min => {
5080                    summaries.push(MBD::default());
5081                    anchors.next();
5082                    continue;
5083                }
5084                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5085                Anchor::Max => {
5086                    summaries.push(MBD::from_summary(&self.text_summary()));
5087                    anchors.next();
5088                    continue;
5089                }
5090            };
5091
5092            cursor.seek_forward(&target, Bias::Left);
5093
5094            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5095            if let Some(excerpt) = cursor.item() {
5096                let buffer_snapshot = excerpt.buffer_snapshot(self);
5097                if !excerpt.contains(&excerpt_anchor, self) {
5098                    let position = self.summary_for_excerpt_position_without_hunks(
5099                        Bias::Left,
5100                        excerpt_start_position,
5101                        &mut diff_transforms_cursor,
5102                    );
5103                    summaries.push(position);
5104                    anchors.next();
5105                    continue;
5106                }
5107                let excerpt_buffer_start = excerpt
5108                    .range
5109                    .context
5110                    .start
5111                    .summary::<MBD::TextDimension>(buffer_snapshot);
5112                let excerpt_buffer_end = excerpt
5113                    .range
5114                    .context
5115                    .end
5116                    .summary::<MBD::TextDimension>(buffer_snapshot);
5117                for (buffer_summary, excerpt_anchor) in buffer_snapshot
5118                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5119                        std::iter::from_fn(|| {
5120                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5121                            if !excerpt.contains(&excerpt_anchor, self) {
5122                                return None;
5123                            }
5124                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5125                        }),
5126                    )
5127                {
5128                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5129                    let mut position = excerpt_start_position;
5130                    if summary > excerpt_buffer_start {
5131                        position += summary - excerpt_buffer_start;
5132                    }
5133
5134                    if diff_transforms_cursor.start().0 < position {
5135                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5136                    }
5137
5138                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5139                        excerpt_anchor,
5140                        position,
5141                        &mut diff_transforms_cursor,
5142                        &buffer_snapshot,
5143                    ));
5144                }
5145            } else {
5146                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5147                let position = self.summary_for_excerpt_position_without_hunks(
5148                    Bias::Right,
5149                    excerpt_start_position,
5150                    &mut diff_transforms_cursor,
5151                );
5152                summaries.push(position);
5153                anchors.next();
5154            }
5155        }
5156
5157        summaries
5158    }
5159
5160    pub fn dimensions_from_points<'a, MBD>(
5161        &'a self,
5162        points: impl 'a + IntoIterator<Item = Point>,
5163    ) -> impl 'a + Iterator<Item = MBD>
5164    where
5165        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5166    {
5167        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5168        cursor.seek(&DimensionPair {
5169            key: Point::default(),
5170            value: None,
5171        });
5172        let mut points = points.into_iter();
5173        iter::from_fn(move || {
5174            let point = points.next()?;
5175
5176            cursor.seek_forward(&DimensionPair {
5177                key: point,
5178                value: None,
5179            });
5180
5181            if let Some(region) = cursor.region() {
5182                let overshoot = point - region.range.start.key;
5183                let buffer_point = region.buffer_range.start + overshoot;
5184                let mut position = region.range.start.value.unwrap();
5185                position.add_text_dim(
5186                    &region
5187                        .buffer
5188                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5189                );
5190                if point == region.range.end.key && region.has_trailing_newline {
5191                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5192                }
5193                Some(position)
5194            } else {
5195                Some(MBD::from_summary(&self.text_summary()))
5196            }
5197        })
5198    }
5199
5200    fn excerpts_for_buffer(&self, buffer_id: BufferId) -> impl Iterator<Item = &Excerpt> {
5201        if let Some(buffer_state) = self.buffers.get(&buffer_id) {
5202            let path_key = buffer_state.path_key.clone();
5203            let mut cursor = self.excerpts.cursor::<PathKey>(());
5204            cursor.seek_forward(&path_key, Bias::Left);
5205            Some(iter::from_fn(move || {
5206                let excerpt = cursor.item()?;
5207                if excerpt.path_key != path_key {
5208                    return None;
5209                }
5210                cursor.next();
5211                Some(excerpt)
5212            }))
5213        } else {
5214            None
5215        }
5216        .into_iter()
5217        .flatten()
5218    }
5219
5220    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5221        self.anchor_at(position, Bias::Left)
5222    }
5223
5224    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5225        self.anchor_at(position, Bias::Right)
5226    }
5227
5228    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5229        let offset = position.to_offset(self);
5230
5231        // Find the given position in the diff transforms. Determine the corresponding
5232        // offset in the excerpts, and whether the position is within a deleted hunk.
5233        let mut diff_transforms = self
5234            .diff_transforms
5235            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5236        diff_transforms.seek(&offset, Bias::Right);
5237
5238        if offset == diff_transforms.start().0
5239            && bias == Bias::Left
5240            && let Some(prev_item) = diff_transforms.prev_item()
5241            && let DiffTransform::DeletedHunk { .. } = prev_item
5242        {
5243            diff_transforms.prev();
5244        }
5245        let offset_in_transform = offset - diff_transforms.start().0;
5246        let mut excerpt_offset = diff_transforms.start().1;
5247        let mut diff_base_anchor = None;
5248        if let Some(DiffTransform::DeletedHunk {
5249            buffer_id,
5250            base_text_byte_range,
5251            has_trailing_newline,
5252            ..
5253        }) = diff_transforms.item()
5254        {
5255            let diff = self.diffs.get(buffer_id).expect("missing diff");
5256            if offset_in_transform > base_text_byte_range.len() {
5257                debug_assert!(*has_trailing_newline);
5258                bias = Bias::Right;
5259            } else {
5260                diff_base_anchor = Some(
5261                    diff.base_text()
5262                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5263                );
5264                bias = Bias::Left;
5265            }
5266        } else {
5267            excerpt_offset += MultiBufferOffset(offset_in_transform);
5268        };
5269
5270        let mut excerpts = self
5271            .excerpts
5272            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5273        excerpts.seek(&excerpt_offset, Bias::Right);
5274        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5275            excerpts.prev();
5276        }
5277        if let Some(excerpt) = excerpts.item() {
5278            let buffer_snapshot = excerpt.buffer_snapshot(self);
5279            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5280            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5281                overshoot -= 1;
5282                bias = Bias::Right;
5283            }
5284
5285            let buffer_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
5286            let text_anchor = excerpt.clip_anchor(
5287                buffer_snapshot.anchor_at(buffer_start + overshoot, bias),
5288                self,
5289            );
5290            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5291            let anchor = match diff_base_anchor {
5292                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5293                None => anchor,
5294            };
5295            anchor.into()
5296        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5297        {
5298            Anchor::min()
5299        } else {
5300            Anchor::max()
5301        }
5302    }
5303
5304    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5305    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5306        let buffer = self.as_singleton()?;
5307        if text_anchor
5308            .buffer_id
5309            .is_none_or(|id| id == buffer.remote_id())
5310        {
5311            // todo!() bit hacky, but always right for singletons
5312            Some(Anchor::in_buffer(PathKeyIndex(0), text_anchor))
5313        } else {
5314            None
5315        }
5316    }
5317
5318    /// Creates a multibuffer anchor range for the given buffer anchor range, if any excerpt contains both endpoints.
5319    pub fn anchor_range_in_buffer(
5320        &self,
5321        buffer_id: BufferId,
5322        text_anchor: Range<text::Anchor>,
5323    ) -> Option<Range<Anchor>> {
5324        for excerpt in self.excerpts_for_buffer(buffer_id) {
5325            let buffer_snapshot = excerpt.buffer_snapshot(self);
5326            if excerpt.range.contains(&text_anchor.start, &buffer_snapshot)
5327                && excerpt.range.contains(&text_anchor.end, &buffer_snapshot)
5328            {
5329                return Some(Anchor::range_in_buffer(excerpt.path_key_index, text_anchor));
5330            }
5331        }
5332
5333        None
5334    }
5335
5336    /// Creates a multibuffer anchor for the given buffer anchor, if it is contained in any excerpt.
5337    pub fn anchor_in_buffer(
5338        &self,
5339        buffer_id: BufferId,
5340        text_anchor: text::Anchor,
5341    ) -> Option<Anchor> {
5342        for excerpt in self.excerpts_for_buffer(buffer_id) {
5343            let buffer_snapshot = excerpt.buffer_snapshot(self);
5344            if excerpt.range.contains(&text_anchor, &buffer_snapshot) {
5345                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5346            }
5347        }
5348
5349        None
5350    }
5351
5352    pub fn anchors_in_buffer(
5353        &self,
5354        buffer_id: BufferId,
5355        text_anchors: impl IntoIterator<Item = text::Anchor>,
5356    ) -> Option<impl Iterator<Item = Anchor>> {
5357        let path_key_index = self.path_key_index_for_buffer(buffer_id)?;
5358        Some(
5359            text_anchors
5360                .into_iter()
5361                .map(move |anchor| Anchor::in_buffer(path_key_index, anchor)),
5362        )
5363    }
5364
5365    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5366        match anchor {
5367            // todo(lw): should be `!self.is_empty()`
5368            Anchor::Min | Anchor::Max => true,
5369            Anchor::Excerpt(excerpt_anchor) => {
5370                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5371                    return false;
5372                };
5373                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5374                cursor.seek(&target, Bias::Left);
5375                let Some(excerpt) = cursor.item() else {
5376                    return false;
5377                };
5378                excerpt
5379                    .buffer_snapshot(self)
5380                    .can_resolve(&excerpt_anchor.text_anchor())
5381            }
5382        }
5383    }
5384
5385    pub fn excerpts(&self) -> impl Iterator<Item = (&BufferSnapshot, ExcerptInfo)> {
5386        self.excerpts
5387            .iter()
5388            .map(|excerpt| (excerpt.buffer_snapshot(self), excerpt.info()))
5389    }
5390
5391    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5392    where
5393        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5394        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5395    {
5396        let excerpts = self.excerpts.cursor(());
5397        let diff_transforms = self.diff_transforms.cursor(());
5398        MultiBufferCursor {
5399            excerpts,
5400            diff_transforms,
5401            cached_region: OnceCell::new(),
5402            snapshot: self,
5403        }
5404    }
5405
5406    pub fn excerpt_before(&self, anchor: Anchor) -> Option<ExcerptInfo> {
5407        let target = anchor.try_seek_target(&self)?;
5408        let mut excerpts = self.excerpts.cursor::<ExcerptSummary>(());
5409        excerpts.seek(&target, Bias::Left);
5410        excerpts.prev();
5411        Some(excerpts.item()?.info())
5412    }
5413
5414    pub fn excerpt_boundaries_in_range<R, T>(
5415        &self,
5416        range: R,
5417    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5418    where
5419        R: RangeBounds<T>,
5420        T: ToOffset,
5421    {
5422        let start_offset;
5423        let start = match range.start_bound() {
5424            Bound::Included(start) => {
5425                start_offset = start.to_offset(self);
5426                Bound::Included(start_offset)
5427            }
5428            Bound::Excluded(_) => {
5429                panic!("not supported")
5430            }
5431            Bound::Unbounded => {
5432                start_offset = MultiBufferOffset::ZERO;
5433                Bound::Unbounded
5434            }
5435        };
5436        let end = match range.end_bound() {
5437            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5438            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5439            Bound::Unbounded => Bound::Unbounded,
5440        };
5441        let bounds = (start, end);
5442        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5443        cursor.seek(&DimensionPair {
5444            key: start_offset,
5445            value: None,
5446        });
5447
5448        if cursor
5449            .fetch_excerpt_with_range()
5450            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5451        {
5452            cursor.prev_excerpt();
5453        } else {
5454            cursor.seek_to_start_of_current_excerpt();
5455        }
5456        let mut prev_excerpt = cursor
5457            .fetch_excerpt_with_range()
5458            .map(|(excerpt, _)| excerpt);
5459
5460        cursor.next_excerpt_forwards();
5461
5462        iter::from_fn(move || {
5463            loop {
5464                if self.singleton {
5465                    return None;
5466                }
5467
5468                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5469                cursor.next_excerpt_forwards();
5470                if !bounds.contains(&next_range.start.key) {
5471                    prev_excerpt = Some(next_excerpt);
5472                    continue;
5473                }
5474
5475                let next_region_start = next_range.start.value.unwrap();
5476                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5477                    range.start.value.unwrap()
5478                } else {
5479                    self.max_point()
5480                };
5481
5482                let prev = prev_excerpt.as_ref().map(|excerpt| ExcerptBoundaryInfo {
5483                    path_key_index: excerpt.path_key_index,
5484                    buffer: excerpt.buffer_snapshot(self).clone(),
5485                    range: excerpt.range.clone(),
5486                    end_row: MultiBufferRow(next_region_start.row),
5487                });
5488
5489                let next = ExcerptBoundaryInfo {
5490                    path_key_index: next_excerpt.path_key_index,
5491                    buffer: next_excerpt.buffer_snapshot(self).clone(),
5492                    range: next_excerpt.range.clone(),
5493                    end_row: if next_excerpt.has_trailing_newline {
5494                        MultiBufferRow(next_region_end.row - 1)
5495                    } else {
5496                        MultiBufferRow(next_region_end.row)
5497                    },
5498                };
5499
5500                let row = MultiBufferRow(next_region_start.row);
5501
5502                prev_excerpt = Some(next_excerpt);
5503
5504                return Some(ExcerptBoundary { row, prev, next });
5505            }
5506        })
5507    }
5508
5509    pub fn edit_count(&self) -> usize {
5510        self.edit_count
5511    }
5512
5513    pub fn non_text_state_update_count(&self) -> usize {
5514        self.non_text_state_update_count
5515    }
5516
5517    /// Returns the smallest enclosing bracket ranges containing the given range or
5518    /// None if no brackets contain range or the range is not contained in a single
5519    /// excerpt
5520    ///
5521    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5522    #[ztracing::instrument(skip_all)]
5523    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5524        &self,
5525        range: Range<T>,
5526        range_filter: Option<
5527            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5528        >,
5529    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5530        let range = range.start.to_offset(self)..range.end.to_offset(self);
5531        let mut excerpt = self.excerpt_containing(range.clone())?;
5532        let buffer_snapshot = excerpt.buffer(self).clone();
5533        let excerpt_buffer_range = excerpt.buffer_range(self);
5534
5535        // Filter to ranges contained in the excerpt
5536        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5537            excerpt_buffer_range.contains(&BufferOffset(open.start))
5538                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5539                && range_filter.is_none_or(|filter| {
5540                    filter(
5541                        &buffer_snapshot,
5542                        BufferOffset(open.start)..BufferOffset(close.end),
5543                        BufferOffset(close.start)..BufferOffset(close.end),
5544                    )
5545                })
5546        };
5547
5548        let (open, close) = buffer_snapshot.innermost_enclosing_bracket_ranges(
5549            excerpt.map_range_to_buffer(range),
5550            Some(&range_filter),
5551        )?;
5552
5553        Some((
5554            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5555            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5556        ))
5557    }
5558
5559    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5560    /// not contained in a single excerpt
5561    pub fn enclosing_bracket_ranges<T: ToOffset>(
5562        &self,
5563        range: Range<T>,
5564    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5565    {
5566        let range = range.start.to_offset(self)..range.end.to_offset(self);
5567        let mut excerpt = self.excerpt_containing(range.clone())?;
5568
5569        Some(
5570            excerpt
5571                .buffer(self)
5572                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5573                .filter_map(move |pair| {
5574                    let open_range =
5575                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5576                    let close_range =
5577                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5578                    if excerpt.contains_buffer_range(open_range.start..close_range.end, self) {
5579                        Some((
5580                            excerpt.map_range_from_buffer(open_range),
5581                            excerpt.map_range_from_buffer(close_range),
5582                        ))
5583                    } else {
5584                        None
5585                    }
5586                }),
5587        )
5588    }
5589
5590    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5591    /// not contained in a single excerpt
5592    pub fn text_object_ranges<T: ToOffset>(
5593        &self,
5594        range: Range<T>,
5595        options: TreeSitterOptions,
5596    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5597        let range = range.start.to_offset(self)..range.end.to_offset(self);
5598        self.excerpt_containing(range.clone())
5599            .map(|mut excerpt| {
5600                excerpt
5601                    .buffer(self)
5602                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5603                    .filter_map(move |(range, text_object)| {
5604                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5605                        if excerpt.contains_buffer_range(range.clone(), self) {
5606                            Some((excerpt.map_range_from_buffer(range), text_object))
5607                        } else {
5608                            None
5609                        }
5610                    })
5611            })
5612            .into_iter()
5613            .flatten()
5614    }
5615
5616    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5617    /// not contained in a single excerpt
5618    pub fn bracket_ranges<T: ToOffset>(
5619        &self,
5620        range: Range<T>,
5621    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5622    {
5623        let range = range.start.to_offset(self)..range.end.to_offset(self);
5624        let mut excerpt = self.excerpt_containing(range.clone())?;
5625        Some(
5626            excerpt
5627                .buffer(self)
5628                .bracket_ranges(excerpt.map_range_to_buffer(range))
5629                .filter_map(move |pair| {
5630                    let open_range =
5631                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5632                    let close_range =
5633                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5634                    excerpt
5635                        .contains_buffer_range(open_range.start..close_range.end, self)
5636                        .then(|| BracketMatch {
5637                            open_range: excerpt.map_range_from_buffer(open_range),
5638                            close_range: excerpt.map_range_from_buffer(close_range),
5639                            color_index: pair.color_index,
5640                            newline_only: pair.newline_only,
5641                            syntax_layer_depth: pair.syntax_layer_depth,
5642                        })
5643                })
5644                .map(BracketMatch::bracket_ranges),
5645        )
5646    }
5647
5648    pub fn redacted_ranges<'a, T: ToOffset>(
5649        &'a self,
5650        range: Range<T>,
5651        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5652    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5653        let range = range.start.to_offset(self)..range.end.to_offset(self);
5654        self.lift_buffer_metadata(range, move |buffer, range| {
5655            if redaction_enabled(buffer.file()) {
5656                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5657            } else {
5658                None
5659            }
5660        })
5661        .map(|(range, _, _)| range)
5662    }
5663
5664    pub fn runnable_ranges(
5665        &self,
5666        range: Range<Anchor>,
5667    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5668        let range = range.start.to_offset(self)..range.end.to_offset(self);
5669        self.lift_buffer_metadata(range, move |buffer, range| {
5670            Some(
5671                buffer
5672                    .runnable_ranges(range.clone())
5673                    .filter(move |runnable| {
5674                        runnable.run_range.start >= range.start
5675                            && runnable.run_range.end < range.end
5676                    })
5677                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5678            )
5679        })
5680        .map(|(run_range, runnable, _)| (run_range, runnable))
5681    }
5682
5683    pub fn line_indents(
5684        &self,
5685        start_row: MultiBufferRow,
5686        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5687    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5688        let max_point = self.max_point();
5689        let mut cursor = self.cursor::<Point, Point>();
5690        cursor.seek(&Point::new(start_row.0, 0));
5691        iter::from_fn(move || {
5692            let mut region = cursor.region()?;
5693            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5694                cursor.next();
5695                region = cursor.region()?;
5696            }
5697            let region = cursor.region()?;
5698            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5699            let buffer_start_row =
5700                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5701
5702            let buffer_end_row = if region.is_main_buffer
5703                && (region.has_trailing_newline || region.range.end == max_point)
5704            {
5705                region.buffer_range.end.row
5706            } else {
5707                region.buffer_range.end.row.saturating_sub(1)
5708            };
5709
5710            let line_indents = region
5711                .buffer
5712                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5713            let region_buffer_row = region.buffer_range.start.row;
5714            let region_row = region.range.start.row;
5715            let region_buffer = region.excerpt.buffer_snapshot(self);
5716            cursor.next();
5717            Some(line_indents.map(move |(buffer_row, indent)| {
5718                let row = region_row + (buffer_row - region_buffer_row);
5719                (MultiBufferRow(row), indent, region_buffer)
5720            }))
5721        })
5722        .flatten()
5723    }
5724
5725    pub fn reversed_line_indents(
5726        &self,
5727        end_row: MultiBufferRow,
5728        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5729    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5730        let max_point = self.max_point();
5731        let mut cursor = self.cursor::<Point, Point>();
5732        cursor.seek(&Point::new(end_row.0, 0));
5733        iter::from_fn(move || {
5734            let mut region = cursor.region()?;
5735            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5736                cursor.prev();
5737                region = cursor.region()?;
5738            }
5739            let region = cursor.region()?;
5740
5741            let buffer_start_row = region.buffer_range.start.row;
5742            let buffer_end_row = if region.is_main_buffer
5743                && (region.has_trailing_newline || region.range.end == max_point)
5744            {
5745                region.buffer_range.end.row + 1
5746            } else {
5747                region.buffer_range.end.row
5748            };
5749
5750            let overshoot = end_row.0 - region.range.start.row;
5751            let buffer_end_row =
5752                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5753
5754            let line_indents = region
5755                .buffer
5756                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5757            let region_buffer_row = region.buffer_range.start.row;
5758            let region_row = region.range.start.row;
5759            let region_buffer = region.excerpt.buffer_snapshot(self);
5760            cursor.prev();
5761            Some(line_indents.map(move |(buffer_row, indent)| {
5762                let row = region_row + (buffer_row - region_buffer_row);
5763                (MultiBufferRow(row), indent, region_buffer)
5764            }))
5765        })
5766        .flatten()
5767    }
5768
5769    pub async fn enclosing_indent(
5770        &self,
5771        mut target_row: MultiBufferRow,
5772    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5773        let max_row = MultiBufferRow(self.max_point().row);
5774        if target_row >= max_row {
5775            return None;
5776        }
5777
5778        let mut target_indent = self.line_indent_for_row(target_row);
5779
5780        // If the current row is at the start of an indented block, we want to return this
5781        // block as the enclosing indent.
5782        if !target_indent.is_line_empty() && target_row < max_row {
5783            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5784            if !next_line_indent.is_line_empty()
5785                && target_indent.raw_len() < next_line_indent.raw_len()
5786            {
5787                target_indent = next_line_indent;
5788                target_row.0 += 1;
5789            }
5790        }
5791
5792        const SEARCH_ROW_LIMIT: u32 = 25000;
5793        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5794        const YIELD_INTERVAL: u32 = 100;
5795
5796        let mut accessed_row_counter = 0;
5797
5798        // If there is a blank line at the current row, search for the next non indented lines
5799        if target_indent.is_line_empty() {
5800            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5801            let end =
5802                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5803
5804            let mut non_empty_line_above = None;
5805            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5806                if row < start {
5807                    break;
5808                }
5809                accessed_row_counter += 1;
5810                if accessed_row_counter == YIELD_INTERVAL {
5811                    accessed_row_counter = 0;
5812                    yield_now().await;
5813                }
5814                if !indent.is_line_empty() {
5815                    non_empty_line_above = Some((row, indent));
5816                    break;
5817                }
5818            }
5819
5820            let mut non_empty_line_below = None;
5821            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5822                if row > end {
5823                    break;
5824                }
5825                accessed_row_counter += 1;
5826                if accessed_row_counter == YIELD_INTERVAL {
5827                    accessed_row_counter = 0;
5828                    yield_now().await;
5829                }
5830                if !indent.is_line_empty() {
5831                    non_empty_line_below = Some((row, indent));
5832                    break;
5833                }
5834            }
5835
5836            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5837                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5838                    if above_indent.raw_len() >= below_indent.raw_len() {
5839                        (above_row, above_indent)
5840                    } else {
5841                        (below_row, below_indent)
5842                    }
5843                }
5844                (Some(above), None) => above,
5845                (None, Some(below)) => below,
5846                _ => return None,
5847            };
5848
5849            target_indent = indent;
5850            target_row = row;
5851        }
5852
5853        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5854        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5855
5856        let mut start_indent = None;
5857        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5858            if row < start {
5859                break;
5860            }
5861            accessed_row_counter += 1;
5862            if accessed_row_counter == YIELD_INTERVAL {
5863                accessed_row_counter = 0;
5864                yield_now().await;
5865            }
5866            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5867                start_indent = Some((row, indent));
5868                break;
5869            }
5870        }
5871        let (start_row, start_indent_size) = start_indent?;
5872
5873        let mut end_indent = (end, None);
5874        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5875            if row > end {
5876                break;
5877            }
5878            accessed_row_counter += 1;
5879            if accessed_row_counter == YIELD_INTERVAL {
5880                accessed_row_counter = 0;
5881                yield_now().await;
5882            }
5883            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5884                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5885                break;
5886            }
5887        }
5888        let (end_row, end_indent_size) = end_indent;
5889
5890        let indent = if let Some(end_indent_size) = end_indent_size {
5891            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5892                start_indent_size
5893            } else {
5894                end_indent_size
5895            }
5896        } else {
5897            start_indent_size
5898        };
5899
5900        Some((start_row..end_row, indent))
5901    }
5902
5903    pub fn indent_guides_in_range<T: ToPoint>(
5904        &self,
5905        range: Range<T>,
5906        ignore_disabled_for_language: bool,
5907        cx: &App,
5908    ) -> impl Iterator<Item = IndentGuide> {
5909        let range = range.start.to_point(self)..range.end.to_point(self);
5910        let start_row = MultiBufferRow(range.start.row);
5911        let end_row = MultiBufferRow(range.end.row);
5912
5913        let mut row_indents = self.line_indents(start_row, |buffer| {
5914            let settings =
5915                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5916            settings.indent_guides.enabled || ignore_disabled_for_language
5917        });
5918
5919        let mut result = Vec::new();
5920        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5921
5922        let mut prev_settings = None;
5923        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5924            if first_row > end_row {
5925                break;
5926            }
5927            let current_depth = indent_stack.len() as u32;
5928
5929            // Avoid retrieving the language settings repeatedly for every buffer row.
5930            if let Some((prev_buffer_id, _)) = &prev_settings
5931                && prev_buffer_id != &buffer.remote_id()
5932            {
5933                prev_settings.take();
5934            }
5935            let settings = &prev_settings
5936                .get_or_insert_with(|| {
5937                    (
5938                        buffer.remote_id(),
5939                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5940                    )
5941                })
5942                .1;
5943            let tab_size = settings.tab_size.get();
5944
5945            // When encountering empty, continue until found useful line indent
5946            // then add to the indent stack with the depth found
5947            let mut found_indent = false;
5948            let mut last_row = first_row;
5949            if line_indent.is_line_blank() {
5950                while !found_indent {
5951                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5952                        break;
5953                    };
5954                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5955                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5956                        break;
5957                    }
5958
5959                    if new_line_indent.is_line_blank() {
5960                        continue;
5961                    }
5962                    last_row = target_row.min(end_row);
5963                    line_indent = new_line_indent;
5964                    found_indent = true;
5965                    break;
5966                }
5967            } else {
5968                found_indent = true
5969            }
5970
5971            let depth = if found_indent {
5972                line_indent.len(tab_size) / tab_size
5973            } else {
5974                0
5975            };
5976
5977            match depth.cmp(&current_depth) {
5978                cmp::Ordering::Less => {
5979                    for _ in 0..(current_depth - depth) {
5980                        let mut indent = indent_stack.pop().unwrap();
5981                        if last_row != first_row {
5982                            // In this case, we landed on an empty row, had to seek forward,
5983                            // and discovered that the indent we where on is ending.
5984                            // This means that the last display row must
5985                            // be on line that ends this indent range, so we
5986                            // should display the range up to the first non-empty line
5987                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5988                        }
5989
5990                        result.push(indent)
5991                    }
5992                }
5993                cmp::Ordering::Greater => {
5994                    for next_depth in current_depth..depth {
5995                        indent_stack.push(IndentGuide {
5996                            buffer_id: buffer.remote_id(),
5997                            start_row: first_row,
5998                            end_row: last_row,
5999                            depth: next_depth,
6000                            tab_size,
6001                            settings: settings.indent_guides.clone(),
6002                        });
6003                    }
6004                }
6005                _ => {}
6006            }
6007
6008            for indent in indent_stack.iter_mut() {
6009                indent.end_row = last_row;
6010            }
6011        }
6012
6013        result.extend(indent_stack);
6014        result.into_iter()
6015    }
6016
6017    pub fn trailing_excerpt_update_count(&self) -> usize {
6018        self.trailing_excerpt_update_count
6019    }
6020
6021    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6022        self.point_to_buffer_offset(point)
6023            .and_then(|(buffer, _)| buffer.file())
6024    }
6025
6026    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6027        self.point_to_buffer_offset(offset)
6028            .and_then(|(buffer, offset)| buffer.language_at(offset))
6029    }
6030
6031    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6032        self.excerpts
6033            .first()
6034            .map(|excerpt| excerpt.buffer_snapshot(self))
6035            .map(|buffer| {
6036                language_settings(
6037                    buffer.language().map(|language| language.name()),
6038                    buffer.file(),
6039                    cx,
6040                )
6041            })
6042            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6043    }
6044
6045    pub fn language_settings_at<'a, T: ToOffset>(
6046        &'a self,
6047        point: T,
6048        cx: &'a App,
6049    ) -> Cow<'a, LanguageSettings> {
6050        let mut language = None;
6051        let mut file = None;
6052        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6053            language = buffer.language_at(offset);
6054            file = buffer.file();
6055        }
6056        language_settings(language.map(|l| l.name()), file, cx)
6057    }
6058
6059    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6060        self.point_to_buffer_offset(point)
6061            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6062    }
6063
6064    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6065        self.point_to_buffer_offset(point)
6066            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6067            .unwrap_or_default()
6068    }
6069
6070    pub fn language_indent_size_at<T: ToOffset>(
6071        &self,
6072        position: T,
6073        cx: &App,
6074    ) -> Option<IndentSize> {
6075        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6076        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6077    }
6078
6079    pub fn is_dirty(&self) -> bool {
6080        self.is_dirty
6081    }
6082
6083    pub fn has_deleted_file(&self) -> bool {
6084        self.has_deleted_file
6085    }
6086
6087    pub fn has_conflict(&self) -> bool {
6088        self.has_conflict
6089    }
6090
6091    pub fn has_diagnostics(&self) -> bool {
6092        self.excerpts
6093            .iter()
6094            .any(|excerpt| excerpt.buffer_snapshot(self).has_diagnostics())
6095    }
6096
6097    pub fn diagnostic_group(
6098        &self,
6099        buffer_id: BufferId,
6100        group_id: usize,
6101    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6102        self.lift_buffer_metadata::<Point, _, _>(
6103            Point::zero()..self.max_point(),
6104            move |buffer, range| {
6105                if buffer.remote_id() != buffer_id {
6106                    return None;
6107                };
6108                Some(
6109                    buffer
6110                        .diagnostics_in_range(range, false)
6111                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6112                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6113                )
6114            },
6115        )
6116        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6117    }
6118
6119    pub fn diagnostics_in_range<'a, MBD>(
6120        &'a self,
6121        range: Range<MBD>,
6122    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6123    where
6124        MBD::TextDimension: 'a
6125            + text::ToOffset
6126            + text::FromAnchor
6127            + Sub<Output = MBD::TextDimension>
6128            + fmt::Debug
6129            + ops::Add<Output = MBD::TextDimension>
6130            + ops::AddAssign
6131            + Ord,
6132        MBD: MultiBufferDimension
6133            + Ord
6134            + Sub<Output = MBD::TextDimension>
6135            + ops::Add<MBD::TextDimension, Output = MBD>
6136            + ops::AddAssign<MBD::TextDimension>
6137            + 'a,
6138    {
6139        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6140            Some(
6141                buffer
6142                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6143                    .map(|entry| (entry.range, entry.diagnostic)),
6144            )
6145        })
6146        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6147    }
6148
6149    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6150        &'a self,
6151        range: Range<MBD>,
6152    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6153    where
6154        MBD: MultiBufferDimension
6155            + Ord
6156            + Sub<Output = MBD::TextDimension>
6157            + ops::Add<MBD::TextDimension, Output = MBD>
6158            + ops::AddAssign<MBD::TextDimension>,
6159        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6160            + ops::Add<Output = MBD::TextDimension>
6161            + text::ToOffset
6162            + text::FromAnchor
6163            + AddAssign<MBD::TextDimension>
6164            + Ord,
6165    {
6166        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6167            Some(
6168                buffer
6169                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6170                    .map(|entry| (entry.range, entry.diagnostic)),
6171            )
6172        })
6173        .map(|(range, diagnostic, excerpt)| {
6174            (
6175                excerpt.buffer_snapshot(self).remote_id(),
6176                DiagnosticEntryRef { diagnostic, range },
6177            )
6178        })
6179    }
6180
6181    pub fn syntax_ancestor<T: ToOffset>(
6182        &self,
6183        range: Range<T>,
6184    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6185        let range = range.start.to_offset(self)..range.end.to_offset(self);
6186        let mut excerpt = self.excerpt_containing(range.clone())?;
6187        let node = excerpt
6188            .buffer(self)
6189            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6190        let node_range = node.byte_range();
6191        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6192        if !excerpt.contains_buffer_range(node_range.clone(), self) {
6193            return None;
6194        };
6195        Some((node, excerpt.map_range_from_buffer(node_range)))
6196    }
6197
6198    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6199        let buffer = self.as_singleton()?;
6200        let outline = buffer.outline(theme);
6201        Some(Outline::new(
6202            outline
6203                .items
6204                .into_iter()
6205                .flat_map(|item| {
6206                    Some(OutlineItem {
6207                        depth: item.depth,
6208                        range: self.anchor_range_in_buffer(buffer.remote_id(), item.range)?,
6209                        source_range_for_text: self.anchor_range_in_buffer(
6210                            buffer.remote_id(),
6211                            item.source_range_for_text,
6212                        )?,
6213                        text: item.text,
6214                        highlight_ranges: item.highlight_ranges,
6215                        name_ranges: item.name_ranges,
6216                        body_range: item.body_range.and_then(|body_range| {
6217                            self.anchor_range_in_buffer(buffer.remote_id(), body_range)
6218                        }),
6219                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6220                            self.anchor_range_in_buffer(buffer.remote_id(), annotation_range)
6221                        }),
6222                    })
6223                })
6224                .collect(),
6225        ))
6226    }
6227
6228    pub fn symbols_containing<T: ToOffset>(
6229        &self,
6230        offset: T,
6231        theme: Option<&SyntaxTheme>,
6232    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6233        let anchor = self.anchor_before(offset);
6234        let target = anchor.try_seek_target(&self)?;
6235        let (_, _, excerpt) = self.excerpts.find((), &target, Bias::Left);
6236        let excerpt = excerpt?;
6237        let buffer_snapshot = excerpt.buffer_snapshot(self);
6238        Some((
6239            buffer_snapshot.remote_id(),
6240            buffer_snapshot
6241                .symbols_containing(
6242                    anchor
6243                        .excerpt_anchor()
6244                        .map(|anchor| anchor.text_anchor())
6245                        .unwrap_or(text::Anchor::MIN),
6246                    theme,
6247                )
6248                .into_iter()
6249                .flat_map(|item| {
6250                    Some(OutlineItem {
6251                        depth: item.depth,
6252                        source_range_for_text: Anchor::range_in_buffer(
6253                            excerpt.path_key_index,
6254                            item.source_range_for_text,
6255                        ),
6256                        range: Anchor::range_in_buffer(excerpt.path_key_index, item.range),
6257                        text: item.text,
6258                        highlight_ranges: item.highlight_ranges,
6259                        name_ranges: item.name_ranges,
6260                        body_range: item.body_range.map(|body_range| {
6261                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6262                        }),
6263                        annotation_range: item.annotation_range.map(|body_range| {
6264                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6265                        }),
6266                    })
6267                })
6268                .collect(),
6269        ))
6270    }
6271
6272    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6273        let (_, _, excerpt) = self
6274            .excerpts
6275            .find::<ExcerptSummary, _>((), path, Bias::Left);
6276        Some(excerpt?.buffer_snapshot(self))
6277    }
6278
6279    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6280        Some(&self.buffers.get(&buffer_id)?.path_key)
6281    }
6282
6283    pub fn path_key_index_for_buffer(&self, buffer_id: BufferId) -> Option<PathKeyIndex> {
6284        self.first_excerpt_for_buffer(buffer_id)
6285            .map(|excerpt| excerpt.path_key_index)
6286    }
6287
6288    pub fn first_excerpt_for_buffer(&self, buffer_id: BufferId) -> Option<&Excerpt> {
6289        let path_key = &self.buffers.get(&buffer_id)?.path_key;
6290        self.first_excerpt_for_path(path_key)
6291    }
6292
6293    pub fn first_excerpt_for_path(&self, path_key: &PathKey) -> Option<&Excerpt> {
6294        let (_, _, first_excerpt) =
6295            self.excerpts
6296                .find::<ExcerptSummary, _>((), path_key, Bias::Left);
6297        first_excerpt
6298    }
6299
6300    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6301        self.buffer_for_path(self.path_for_buffer(id)?)
6302    }
6303
6304    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6305        self.path_keys_by_index.get(&anchor.path).cloned()
6306    }
6307
6308    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6309        self.try_path_for_anchor(anchor)
6310            .expect("invalid anchor: path was never added to multibuffer")
6311    }
6312
6313    // todo!() this may not make sense any more
6314    pub fn range_for_excerpt(&self, excerpt_id: BufferId) -> Option<Range<Point>> {
6315        todo!()
6316        // let mut cursor = self
6317        //     .excerpts
6318        //     .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6319        // let locator = self.excerpt_locator_for_id(excerpt_id);
6320        // let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6321        // if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6322        //     sought_exact = true;
6323        //     cursor.prev();
6324        // } else if excerpt_id == ExcerptId::min() {
6325        //     sought_exact = true;
6326        // }
6327        // if sought_exact {
6328        //     let start = cursor.start().1;
6329        //     let end = cursor.end().1;
6330        //     let mut diff_transforms = self
6331        //         .diff_transforms
6332        //         .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6333        //     diff_transforms.seek(&start, Bias::Left);
6334        //     let overshoot = start - diff_transforms.start().0;
6335        //     let start = diff_transforms.start().1 + overshoot;
6336        //     diff_transforms.seek(&end, Bias::Right);
6337        //     let overshoot = end - diff_transforms.start().0;
6338        //     let end = diff_transforms.start().1 + overshoot;
6339        //     Some(start.0..end.0)
6340        // } else {
6341        //     None
6342        // }
6343    }
6344
6345    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6346    pub fn excerpt_containing<T: ToOffset>(
6347        &self,
6348        range: Range<T>,
6349    ) -> Option<MultiBufferExcerpt<'_>> {
6350        let range = range.start.to_offset(self)..range.end.to_offset(self);
6351        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6352        cursor.seek(&range.start);
6353
6354        let start_excerpt = cursor.excerpt()?;
6355        if range.end != range.start {
6356            cursor.seek_forward(&range.end);
6357            if cursor.excerpt()? != start_excerpt {
6358                return None;
6359            }
6360        }
6361
6362        cursor.seek_to_start_of_current_excerpt();
6363        let region = cursor.region()?;
6364        let offset = region.range.start;
6365        let buffer_offset = start_excerpt.buffer_start_offset(self);
6366        let excerpt_offset = *cursor.excerpts.start();
6367        Some(MultiBufferExcerpt {
6368            diff_transforms: cursor.diff_transforms,
6369            excerpt: start_excerpt,
6370            offset,
6371            buffer_offset,
6372            excerpt_offset,
6373        })
6374    }
6375
6376    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6377        match anchor {
6378            Anchor::Min => self.excerpts.first().map(|excerpt| excerpt.buffer_id),
6379            Anchor::Excerpt(excerpt_anchor) => Some(excerpt_anchor.buffer_id),
6380            Anchor::Max => self.excerpts.last().map(|excerpt| excerpt.buffer_id),
6381        }
6382    }
6383
6384    pub fn selections_in_range<'a>(
6385        &'a self,
6386        range: &'a Range<Anchor>,
6387        include_local: bool,
6388    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6389        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6390        cursor.seek(&range.start.seek_target(self), Bias::Left);
6391        cursor
6392            .take_while(move |excerpt| {
6393                let excerpt_start =
6394                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6395                excerpt_start.cmp(&range.end, self).is_le()
6396            })
6397            .flat_map(move |excerpt| {
6398                let buffer_snapshot = excerpt.buffer_snapshot(self);
6399                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6400                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6401                    && excerpt.contains(&excerpt_anchor, self)
6402                {
6403                    query_range.start = excerpt_anchor.text_anchor();
6404                }
6405                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6406                    && excerpt.contains(&excerpt_anchor, self)
6407                {
6408                    query_range.end = excerpt_anchor.text_anchor();
6409                }
6410
6411                buffer_snapshot
6412                    .selections_in_range(query_range, include_local)
6413                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6414                        selections.map(move |selection| {
6415                            let mut start =
6416                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6417                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6418                            if range.start.cmp(&start, self).is_gt() {
6419                                start = range.start;
6420                            }
6421                            if range.end.cmp(&end, self).is_lt() {
6422                                end = range.end;
6423                            }
6424
6425                            (
6426                                replica_id,
6427                                line_mode,
6428                                cursor_shape,
6429                                Selection {
6430                                    id: selection.id,
6431                                    start,
6432                                    end,
6433                                    reversed: selection.reversed,
6434                                    goal: selection.goal,
6435                                },
6436                            )
6437                        })
6438                    })
6439            })
6440    }
6441
6442    pub fn show_headers(&self) -> bool {
6443        self.show_headers
6444    }
6445
6446    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6447        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6448    }
6449
6450    pub fn all_diff_hunks_expanded(&self) -> bool {
6451        self.all_diff_hunks_expanded
6452    }
6453
6454    /// Visually annotates a position or range with the `Debug` representation of a value. The
6455    /// callsite of this function is used as a key - previous annotations will be removed.
6456    #[cfg(debug_assertions)]
6457    #[track_caller]
6458    pub fn debug<V, R>(&self, ranges: &R, value: V)
6459    where
6460        R: debug::ToMultiBufferDebugRanges,
6461        V: std::fmt::Debug,
6462    {
6463        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6464    }
6465
6466    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6467    /// debug annotations with the same key will be removed. The key is also used to determine the
6468    /// annotation's color.
6469    #[cfg(debug_assertions)]
6470    #[track_caller]
6471    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6472    where
6473        K: std::hash::Hash + 'static,
6474        R: debug::ToMultiBufferDebugRanges,
6475        V: std::fmt::Debug,
6476    {
6477        let text_ranges = ranges
6478            .to_multi_buffer_debug_ranges(self)
6479            .into_iter()
6480            .flat_map(|range| {
6481                self.range_to_buffer_ranges(range.start..=range.end)
6482                    .into_iter()
6483                    .map(|(buffer, range)| {
6484                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6485                    })
6486            })
6487            .collect();
6488        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6489            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6490        });
6491    }
6492
6493    fn excerpt_edits_for_diff_change(
6494        &self,
6495        path: &PathKey,
6496        diff_change_range: Range<usize>,
6497    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6498        let mut excerpt_edits = Vec::new();
6499        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6500        cursor.seek(path, Bias::Left);
6501        while let Some(excerpt) = cursor.item()
6502            && &excerpt.path_key == path
6503        {
6504            let buffer_snapshot = excerpt.buffer_snapshot(self);
6505            let excerpt_buffer_range = excerpt.range.context.to_offset(buffer_snapshot);
6506            let excerpt_start = cursor.start().clone();
6507            let excerpt_len = excerpt.text_summary.len;
6508            cursor.next();
6509            if diff_change_range.end < excerpt_buffer_range.start
6510                || diff_change_range.start > excerpt_buffer_range.end
6511            {
6512                continue;
6513            }
6514            let diff_change_start_in_excerpt = diff_change_range
6515                .start
6516                .saturating_sub(excerpt_buffer_range.start);
6517            let diff_change_end_in_excerpt = diff_change_range
6518                .end
6519                .saturating_sub(excerpt_buffer_range.start);
6520            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6521            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6522            excerpt_edits.push(Edit {
6523                old: edit_start..edit_end,
6524                new: edit_start..edit_end,
6525            });
6526        }
6527        excerpt_edits
6528    }
6529
6530    fn excerpts_for_path<'a>(
6531        &'a self,
6532        path_key: &'a PathKey,
6533    ) -> impl Iterator<Item = ExcerptInfo> + 'a {
6534        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6535        cursor.seek(path_key, Bias::Left);
6536        cursor
6537            .take_while(move |item| &item.path_key == path_key)
6538            .map(|excerpt| excerpt.info())
6539    }
6540}
6541
6542#[cfg(any(test, feature = "test-support"))]
6543impl MultiBufferSnapshot {
6544    pub fn random_byte_range(
6545        &self,
6546        start_offset: MultiBufferOffset,
6547        rng: &mut impl rand::Rng,
6548    ) -> Range<MultiBufferOffset> {
6549        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6550        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6551        start..end
6552    }
6553
6554    #[cfg(any(test, feature = "test-support"))]
6555    fn check_invariants(&self) {
6556        let excerpts = self.excerpts.items(());
6557
6558        let all_buffer_path_keys =
6559            HashSet::from_iter(self.buffers.values().map(|b| b.path_key.clone()));
6560        let all_excerpt_path_keys = HashSet::from_iter(excerpts.iter().map(|e| e.path_key.clone()));
6561
6562        for (ix, excerpt) in excerpts.iter().enumerate() {
6563            if ix > 0 {
6564                let prev = &excerpts[ix - 1];
6565
6566                if excerpt.path_key < prev.path_key {
6567                    panic!("excerpt path_keys are out-of-order: {:?}", excerpts);
6568                } else if excerpt.path_key == prev.path_key {
6569                    if excerpt
6570                        .start_anchor()
6571                        .cmp(&prev.end_anchor(), &self)
6572                        .is_le()
6573                    {
6574                        panic!("excerpt anchors are out-of-order: {:?}", excerpts);
6575                    }
6576                    if excerpt
6577                        .start_anchor()
6578                        .cmp(&excerpt.end_anchor(), &self)
6579                        .is_ge()
6580                    {
6581                        panic!("excerpt with backward range: {:?}", excerpts);
6582                    }
6583                }
6584            }
6585            assert!(
6586                all_buffer_path_keys.contains(&excerpt.path_key),
6587                "excerpt path key not found in active path keys: {:?}",
6588                excerpt.path_key
6589            );
6590            assert_eq!(
6591                self.path_keys_by_index.get(&excerpt.path_key_index),
6592                Some(&excerpt.path_key),
6593                "excerpt path key index does not match path key: {:?}",
6594                excerpt.path_key,
6595            );
6596        }
6597        assert_eq!(all_buffer_path_keys, all_excerpt_path_keys);
6598
6599        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6600            panic!(
6601                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6602                self.excerpts.summary().text,
6603                self.diff_transforms.summary().input,
6604                self.diff_transforms.items(()),
6605            );
6606        }
6607
6608        let mut prev_transform: Option<&DiffTransform> = None;
6609        for item in self.diff_transforms.iter() {
6610            if let DiffTransform::BufferContent {
6611                summary,
6612                inserted_hunk_info,
6613            } = item
6614            {
6615                if let Some(DiffTransform::BufferContent {
6616                    inserted_hunk_info: prev_inserted_hunk_info,
6617                    ..
6618                }) = prev_transform
6619                    && *inserted_hunk_info == *prev_inserted_hunk_info
6620                {
6621                    panic!(
6622                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6623                        self.diff_transforms.items(())
6624                    );
6625                }
6626                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6627                    panic!("empty buffer content transform");
6628                }
6629            }
6630            prev_transform = Some(item);
6631        }
6632    }
6633}
6634
6635impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6636where
6637    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6638    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6639{
6640    #[instrument(skip_all)]
6641    fn seek(&mut self, position: &MBD) {
6642        let position = OutputDimension(*position);
6643        self.cached_region.take();
6644        self.diff_transforms.seek(&position, Bias::Right);
6645        if self.diff_transforms.item().is_none()
6646            && self.diff_transforms.start().output_dimension == position
6647        {
6648            self.diff_transforms.prev();
6649        }
6650
6651        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6652        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6653            let overshoot = position - self.diff_transforms.start().output_dimension;
6654            excerpt_position += overshoot;
6655        }
6656
6657        self.excerpts.seek(&excerpt_position, Bias::Right);
6658        if self.excerpts.item().is_none() && dbg!(excerpt_position) == *self.excerpts.start() {
6659            dbg!("NONE");
6660            self.excerpts.prev();
6661        }
6662    }
6663
6664    fn seek_forward(&mut self, position: &MBD) {
6665        let position = OutputDimension(*position);
6666        self.cached_region.take();
6667        self.diff_transforms.seek_forward(&position, Bias::Right);
6668        if self.diff_transforms.item().is_none()
6669            && self.diff_transforms.start().output_dimension == position
6670        {
6671            self.diff_transforms.prev();
6672        }
6673
6674        let overshoot = position - self.diff_transforms.start().output_dimension;
6675        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6676        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6677            excerpt_position += overshoot;
6678        }
6679
6680        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6681        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6682            self.excerpts.prev();
6683        }
6684    }
6685
6686    fn next_excerpt(&mut self) {
6687        self.excerpts.next();
6688        self.seek_to_start_of_current_excerpt();
6689    }
6690
6691    fn prev_excerpt(&mut self) {
6692        self.excerpts.prev();
6693        self.seek_to_start_of_current_excerpt();
6694    }
6695
6696    fn seek_to_start_of_current_excerpt(&mut self) {
6697        self.cached_region.take();
6698
6699        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6700            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6701            && self.diff_transforms.next_item().is_some()
6702        {
6703            self.diff_transforms.next();
6704        }
6705    }
6706
6707    fn next_excerpt_forwards(&mut self) {
6708        self.excerpts.next();
6709        self.seek_to_start_of_current_excerpt_forward();
6710    }
6711
6712    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6713        self.cached_region.take();
6714
6715        if self
6716            .diff_transforms
6717            .seek_forward(self.excerpts.start(), Bias::Left)
6718            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6719            && self.diff_transforms.next_item().is_some()
6720        {
6721            self.diff_transforms.next();
6722        }
6723    }
6724
6725    fn next(&mut self) {
6726        self.cached_region.take();
6727        match self
6728            .diff_transforms
6729            .end()
6730            .excerpt_dimension
6731            .cmp(&self.excerpts.end())
6732        {
6733            cmp::Ordering::Less => self.diff_transforms.next(),
6734            cmp::Ordering::Greater => self.excerpts.next(),
6735            cmp::Ordering::Equal => {
6736                self.diff_transforms.next();
6737                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6738                    || self.diff_transforms.item().is_none()
6739                {
6740                    self.excerpts.next();
6741                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6742                    self.diff_transforms.item()
6743                    && self
6744                        .excerpts
6745                        .item()
6746                        .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end)
6747                {
6748                    self.excerpts.next();
6749                }
6750            }
6751        }
6752    }
6753
6754    fn prev(&mut self) {
6755        self.cached_region.take();
6756        match self
6757            .diff_transforms
6758            .start()
6759            .excerpt_dimension
6760            .cmp(self.excerpts.start())
6761        {
6762            cmp::Ordering::Less => self.excerpts.prev(),
6763            cmp::Ordering::Greater => self.diff_transforms.prev(),
6764            cmp::Ordering::Equal => {
6765                self.diff_transforms.prev();
6766                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6767                    || self.diff_transforms.item().is_none()
6768                {
6769                    self.excerpts.prev();
6770                }
6771            }
6772        }
6773    }
6774
6775    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
6776        self.cached_region
6777            .get_or_init(|| self.build_region())
6778            .as_ref()
6779    }
6780
6781    fn is_at_start_of_excerpt(&mut self) -> bool {
6782        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6783            return false;
6784        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6785            return true;
6786        }
6787
6788        self.diff_transforms.prev();
6789        let prev_transform = self.diff_transforms.item();
6790        self.diff_transforms.next();
6791
6792        prev_transform.is_none_or(|next_transform| {
6793            matches!(next_transform, DiffTransform::BufferContent { .. })
6794        })
6795    }
6796
6797    fn is_at_end_of_excerpt(&self) -> bool {
6798        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6799            return false;
6800        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6801            || self.diff_transforms.item().is_none()
6802        {
6803            return true;
6804        }
6805
6806        let next_transform = self.diff_transforms.next_item();
6807        next_transform.is_none_or(|next_transform| match next_transform {
6808            DiffTransform::BufferContent { .. } => true,
6809            DiffTransform::DeletedHunk { hunk_info, .. } => self
6810                .excerpts
6811                .item()
6812                .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end),
6813        })
6814    }
6815
6816    fn main_buffer_position(&self) -> Option<BD> {
6817        let excerpt = self.excerpts.item()?;
6818        let buffer = excerpt.buffer_snapshot(self.snapshot);
6819        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6820        let mut buffer_start = buffer_context_start;
6821        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6822        buffer_start += overshoot;
6823        Some(buffer_start)
6824    }
6825
6826    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6827        let excerpt = self.excerpts.item()?;
6828        dbg!("GOT EXCERPT");
6829        match self.diff_transforms.item()? {
6830            DiffTransform::DeletedHunk {
6831                buffer_id,
6832                base_text_byte_range,
6833                has_trailing_newline,
6834                hunk_info,
6835                ..
6836            } => {
6837                let diff = self.snapshot.diffs.get(buffer_id)?;
6838                let buffer = diff.base_text();
6839                let mut rope_cursor = buffer.as_rope().cursor(0);
6840                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6841                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6842                let mut buffer_end = buffer_start;
6843                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6844                let start = self.diff_transforms.start().output_dimension.0;
6845                let end = self.diff_transforms.end().output_dimension.0;
6846                Some(MultiBufferRegion {
6847                    buffer,
6848                    excerpt,
6849                    has_trailing_newline: *has_trailing_newline,
6850                    is_main_buffer: false,
6851                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6852                        hunk_info.hunk_secondary_status,
6853                    )),
6854                    buffer_range: buffer_start..buffer_end,
6855                    range: start..end,
6856                })
6857            }
6858            DiffTransform::BufferContent {
6859                inserted_hunk_info, ..
6860            } => {
6861                let buffer = excerpt.buffer_snapshot(self.snapshot);
6862                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6863
6864                let mut start = self.diff_transforms.start().output_dimension.0;
6865                let mut buffer_start = buffer_context_start;
6866                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6867                    let overshoot =
6868                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6869                    start += overshoot;
6870                } else {
6871                    let overshoot =
6872                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6873                    buffer_start += overshoot;
6874                }
6875
6876                let mut end;
6877                let mut buffer_end;
6878                let has_trailing_newline;
6879                let transform_end = self.diff_transforms.end();
6880                if transform_end.excerpt_dimension < self.excerpts.end() {
6881                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
6882                    end = transform_end.output_dimension.0;
6883                    buffer_end = buffer_context_start;
6884                    buffer_end += overshoot;
6885                    has_trailing_newline = false;
6886                } else {
6887                    let overshoot =
6888                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6889                    end = self.diff_transforms.start().output_dimension.0;
6890                    end += overshoot;
6891                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6892                    has_trailing_newline = excerpt.has_trailing_newline;
6893                };
6894
6895                let diff_hunk_status = inserted_hunk_info.map(|info| {
6896                    if info.is_logically_deleted {
6897                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6898                    } else {
6899                        DiffHunkStatus::added(info.hunk_secondary_status)
6900                    }
6901                });
6902
6903                Some(MultiBufferRegion {
6904                    buffer,
6905                    excerpt,
6906                    has_trailing_newline,
6907                    is_main_buffer: true,
6908                    diff_hunk_status,
6909                    buffer_range: buffer_start..buffer_end,
6910                    range: start..end,
6911                })
6912            }
6913        }
6914    }
6915
6916    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
6917        let excerpt = self.excerpts.item()?;
6918        match self.diff_transforms.item()? {
6919            &DiffTransform::DeletedHunk { .. } => {
6920                let start = self.diff_transforms.start().output_dimension.0;
6921                let end = self.diff_transforms.end().output_dimension.0;
6922                Some((excerpt, start..end))
6923            }
6924            DiffTransform::BufferContent { .. } => {
6925                let mut start = self.diff_transforms.start().output_dimension.0;
6926                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6927                    let overshoot =
6928                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6929                    start += overshoot;
6930                }
6931
6932                let mut end;
6933                let transform_end = self.diff_transforms.end();
6934                if transform_end.excerpt_dimension < self.excerpts.end() {
6935                    end = transform_end.output_dimension.0;
6936                } else {
6937                    let overshoot =
6938                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6939                    end = self.diff_transforms.start().output_dimension.0;
6940                    end += overshoot;
6941                };
6942
6943                Some((excerpt, start..end))
6944            }
6945        }
6946    }
6947
6948    fn excerpt(&self) -> Option<&'a Excerpt> {
6949        self.excerpts.item()
6950    }
6951}
6952
6953impl Excerpt {
6954    fn new(
6955        path_key: PathKey,
6956        path_key_index: PathKeyIndex,
6957        buffer_snapshot: &BufferSnapshot,
6958        range: ExcerptRange<text::Anchor>,
6959        has_trailing_newline: bool,
6960    ) -> Self {
6961        dbg!(&path_key, &range, has_trailing_newline);
6962        Excerpt {
6963            path_key,
6964            path_key_index,
6965            buffer_id: buffer_snapshot.remote_id(),
6966            max_buffer_row: range.context.end.to_point(&buffer_snapshot).row,
6967            text_summary: buffer_snapshot.text_summary_for_range::<TextSummary, _>(
6968                range.context.to_offset(&buffer_snapshot),
6969            ),
6970            range,
6971            has_trailing_newline,
6972        }
6973    }
6974
6975    fn buffer_snapshot<'a>(&self, snapshot: &'a MultiBufferSnapshot) -> &'a BufferSnapshot {
6976        &snapshot
6977            .buffers
6978            .get(&self.buffer_id)
6979            .expect("buffer snapshot not found for excerpt")
6980            .buffer_snapshot
6981    }
6982
6983    fn buffer(&self, multibuffer: &MultiBuffer) -> Entity<Buffer> {
6984        multibuffer
6985            .buffer(self.buffer_id)
6986            .expect("buffer entity not found for excerpt")
6987    }
6988
6989    fn info(&self) -> ExcerptInfo {
6990        ExcerptInfo {
6991            path_key_index: self.path_key_index,
6992            buffer_id: self.buffer_id,
6993            range: self.range.clone(),
6994        }
6995    }
6996
6997    fn chunks_in_range<'a>(
6998        &'a self,
6999        range: Range<usize>,
7000        language_aware: bool,
7001        snapshot: &'a MultiBufferSnapshot,
7002    ) -> ExcerptChunks<'a> {
7003        let buffer = self.buffer_snapshot(snapshot);
7004        let content_start = self.range.context.start.to_offset(buffer);
7005        let chunks_start = content_start + range.start;
7006        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7007
7008        let has_footer = self.has_trailing_newline
7009            && range.start <= self.text_summary.len
7010            && range.end > self.text_summary.len;
7011
7012        let content_chunks = buffer.chunks(chunks_start..chunks_end, language_aware);
7013
7014        ExcerptChunks {
7015            content_chunks,
7016            has_footer,
7017            end: self.end_anchor(),
7018        }
7019    }
7020
7021    fn seek_chunks(
7022        &self,
7023        excerpt_chunks: &mut ExcerptChunks,
7024        range: Range<usize>,
7025        snapshot: &MultiBufferSnapshot,
7026    ) {
7027        let buffer = self.buffer_snapshot(snapshot);
7028        let content_start = self.range.context.start.to_offset(buffer);
7029        let chunks_start = content_start + range.start;
7030        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7031        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7032        excerpt_chunks.has_footer = self.has_trailing_newline
7033            && range.start <= self.text_summary.len
7034            && range.end > self.text_summary.len;
7035    }
7036
7037    fn clip_anchor(
7038        &self,
7039        text_anchor: text::Anchor,
7040        snapshot: &MultiBufferSnapshot,
7041    ) -> text::Anchor {
7042        let buffer = self.buffer_snapshot(snapshot);
7043        if text_anchor.cmp(&self.range.context.start, buffer).is_lt() {
7044            self.range.context.start
7045        } else if text_anchor.cmp(&self.range.context.end, buffer).is_gt() {
7046            self.range.context.end
7047        } else {
7048            text_anchor
7049        }
7050    }
7051
7052    pub(crate) fn contains(&self, anchor: &ExcerptAnchor, snapshot: &MultiBufferSnapshot) -> bool {
7053        self.path_key_index == anchor.path
7054            && self.buffer_id == anchor.buffer_id
7055            && self
7056                .range
7057                .contains(&anchor.text_anchor(), self.buffer_snapshot(snapshot))
7058    }
7059
7060    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7061    fn buffer_start_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7062        BufferOffset(
7063            self.range
7064                .context
7065                .start
7066                .to_offset(self.buffer_snapshot(snapshot)),
7067        )
7068    }
7069
7070    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7071    fn buffer_end_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7072        self.buffer_start_offset(snapshot) + self.text_summary.len
7073    }
7074
7075    fn start_anchor(&self) -> ExcerptAnchor {
7076        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.start)
7077    }
7078
7079    fn end_anchor(&self) -> ExcerptAnchor {
7080        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.end)
7081    }
7082}
7083
7084impl PartialEq for Excerpt {
7085    fn eq(&self, other: &Self) -> bool {
7086        self.path_key_index == other.path_key_index
7087            && self.buffer_id == other.buffer_id
7088            && self.range.context == other.range.context
7089    }
7090}
7091
7092impl<'a> MultiBufferExcerpt<'a> {
7093    pub fn buffer_id(&self) -> BufferId {
7094        self.excerpt.buffer_id
7095    }
7096
7097    pub fn start_anchor(&self) -> Anchor {
7098        Anchor::in_buffer(
7099            self.excerpt.path_key_index,
7100            self.excerpt.range.context.start,
7101        )
7102    }
7103
7104    pub fn end_anchor(&self) -> Anchor {
7105        Anchor::in_buffer(self.excerpt.path_key_index, self.excerpt.range.context.end)
7106    }
7107
7108    pub fn buffer<'b>(&self, snapshot: &'b MultiBufferSnapshot) -> &'b BufferSnapshot {
7109        self.excerpt.buffer_snapshot(snapshot)
7110    }
7111
7112    pub fn buffer_range(&self, snapshot: &'a MultiBufferSnapshot) -> Range<BufferOffset> {
7113        self.buffer_offset
7114            ..BufferOffset(
7115                self.excerpt
7116                    .range
7117                    .context
7118                    .end
7119                    .to_offset(&self.excerpt.buffer_snapshot(snapshot).text),
7120            )
7121    }
7122
7123    pub fn start_offset(&self) -> MultiBufferOffset {
7124        self.offset
7125    }
7126
7127    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7128    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7129        self.map_range_to_buffer(offset..offset).start
7130    }
7131
7132    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7133    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7134        self.diff_transforms
7135            .seek(&OutputDimension(range.start), Bias::Right);
7136        let start = self.map_offset_to_buffer_internal(range.start);
7137        let end = if range.end > range.start {
7138            self.diff_transforms
7139                .seek_forward(&OutputDimension(range.end), Bias::Right);
7140            self.map_offset_to_buffer_internal(range.end)
7141        } else {
7142            start
7143        };
7144        start..end
7145    }
7146
7147    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7148        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7149        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7150            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7151        };
7152        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7153        self.buffer_offset + offset_in_excerpt
7154    }
7155
7156    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7157    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7158        self.map_range_from_buffer(buffer_offset..buffer_offset)
7159            .start
7160    }
7161
7162    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7163    pub fn map_range_from_buffer(
7164        &mut self,
7165        buffer_range: Range<BufferOffset>,
7166    ) -> Range<MultiBufferOffset> {
7167        if buffer_range.start < self.buffer_offset {
7168            log::warn!(
7169                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7170            );
7171            return self.offset..self.offset;
7172        }
7173        let overshoot = buffer_range.start - self.buffer_offset;
7174        let excerpt_offset = self.excerpt_offset + overshoot;
7175        let excerpt_seek_dim = excerpt_offset;
7176        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7177        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7178            log::warn!(
7179                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7180            );
7181            return self.offset..self.offset;
7182        }
7183        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7184        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7185
7186        let end = if buffer_range.start < buffer_range.end {
7187            let overshoot = buffer_range.end - self.buffer_offset;
7188            let excerpt_offset = self.excerpt_offset + overshoot;
7189            let excerpt_seek_dim = excerpt_offset;
7190            self.diff_transforms
7191                .seek_forward(&excerpt_seek_dim, Bias::Right);
7192            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7193            // todo(lw): Clamp end to the excerpt boundaries
7194            self.diff_transforms.start().output_dimension.0 + overshoot
7195        } else {
7196            start
7197        };
7198
7199        start..end
7200    }
7201
7202    /// Returns true if the entirety of the given range is in the buffer's excerpt
7203    pub fn contains_buffer_range(
7204        &self,
7205        range: Range<BufferOffset>,
7206        snapshot: &MultiBufferSnapshot,
7207    ) -> bool {
7208        range.start >= self.excerpt.buffer_start_offset(snapshot)
7209            && range.end <= self.excerpt.buffer_end_offset(snapshot)
7210    }
7211
7212    /// Returns true if any part of the given range is in the buffer's excerpt
7213    pub fn contains_partial_buffer_range(
7214        &self,
7215        range: Range<BufferOffset>,
7216        snapshot: &MultiBufferSnapshot,
7217    ) -> bool {
7218        range.start <= self.excerpt.buffer_end_offset(snapshot)
7219            && range.end >= self.excerpt.buffer_start_offset(snapshot)
7220    }
7221
7222    pub fn max_buffer_row(&self) -> u32 {
7223        self.excerpt.max_buffer_row
7224    }
7225}
7226
7227impl fmt::Debug for Excerpt {
7228    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7229        f.debug_struct("Excerpt")
7230            .field("path_key", &self.path_key)
7231            .field("range", &self.range)
7232            .field("text_summary", &self.text_summary)
7233            .field("has_trailing_newline", &self.has_trailing_newline)
7234            .finish()
7235    }
7236}
7237
7238impl sum_tree::Item for Excerpt {
7239    type Summary = ExcerptSummary;
7240
7241    fn summary(&self, _cx: ()) -> Self::Summary {
7242        let mut text = self.text_summary;
7243        if self.has_trailing_newline {
7244            text += TextSummary::from("\n");
7245        }
7246        ExcerptSummary {
7247            path_key: self.path_key.clone(),
7248            max_anchor: self.range.context.end,
7249            widest_line_number: self.max_buffer_row,
7250            text: text.into(),
7251            count: 1,
7252        }
7253    }
7254}
7255
7256impl DiffTransform {
7257    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7258        match self {
7259            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7260            DiffTransform::BufferContent {
7261                inserted_hunk_info, ..
7262            } => *inserted_hunk_info,
7263        }
7264    }
7265}
7266
7267impl sum_tree::Item for DiffTransform {
7268    type Summary = DiffTransformSummary;
7269
7270    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7271        match self {
7272            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7273                input: *summary,
7274                output: *summary,
7275            },
7276            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7277                input: MBTextSummary::default(),
7278                output: summary.into(),
7279            },
7280        }
7281    }
7282}
7283
7284impl DiffTransformSummary {
7285    fn excerpt_len(&self) -> ExcerptOffset {
7286        ExcerptDimension(self.input.len)
7287    }
7288}
7289
7290impl sum_tree::ContextLessSummary for DiffTransformSummary {
7291    fn zero() -> Self {
7292        DiffTransformSummary {
7293            input: MBTextSummary::default(),
7294            output: MBTextSummary::default(),
7295        }
7296    }
7297
7298    fn add_summary(&mut self, other: &Self) {
7299        self.input += other.input;
7300        self.output += other.output;
7301    }
7302}
7303
7304impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7305    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7306        PathKey::min()
7307    }
7308
7309    fn add_summary(
7310        &mut self,
7311        summary: &'_ ExcerptSummary,
7312        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7313    ) {
7314        *self = summary.path_key.clone();
7315    }
7316}
7317
7318impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7319    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7320        MultiBufferOffset::ZERO
7321    }
7322
7323    fn add_summary(
7324        &mut self,
7325        summary: &'_ ExcerptSummary,
7326        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7327    ) {
7328        *self += summary.text.len
7329    }
7330}
7331
7332impl sum_tree::ContextLessSummary for ExcerptSummary {
7333    fn zero() -> Self {
7334        Self::min()
7335    }
7336
7337    fn add_summary(&mut self, summary: &Self) {
7338        debug_assert!(
7339            summary.path_key >= self.path_key,
7340            "Path keys must be in ascending order: {:?} > {:?}",
7341            summary.path_key,
7342            self.path_key
7343        );
7344
7345        self.path_key = summary.path_key.clone();
7346        self.max_anchor = summary.max_anchor;
7347        self.text += summary.text;
7348        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7349        self.count += summary.count;
7350    }
7351}
7352
7353impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7354    fn cmp(
7355        &self,
7356        cursor_location: &ExcerptSummary,
7357        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7358    ) -> cmp::Ordering {
7359        match self {
7360            AnchorSeekTarget::Min => Ordering::Less,
7361            AnchorSeekTarget::Max => Ordering::Greater,
7362            AnchorSeekTarget::Excerpt {
7363                path_key,
7364                anchor,
7365                snapshot,
7366            } => {
7367                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7368                if path_comparison.is_ne() {
7369                    path_comparison
7370                } else if let Some(snapshot) = snapshot {
7371                    // todo!() think more about this..
7372                    // the goal is that if you seek to buffer_id 1 (path key a)
7373                    // and you find that path key a now belongs to buffer_id 2,
7374                    // we'll seek past buffer_id 2.
7375                    if let Some(buffer_id) = cursor_location.max_anchor.buffer_id
7376                        && buffer_id != snapshot.remote_id()
7377                    {
7378                        Ordering::Greater
7379                    } else {
7380                        anchor
7381                            .text_anchor()
7382                            .cmp(&cursor_location.max_anchor, snapshot)
7383                    }
7384                } else {
7385                    // shouldn't happen because we expect this buffer not to have any excerpts
7386                    // (otherwise snapshot would have been Some)
7387                    Ordering::Equal
7388                }
7389            }
7390        }
7391    }
7392}
7393
7394impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7395    fn cmp(
7396        &self,
7397        cursor_location: &ExcerptSummary,
7398        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7399    ) -> cmp::Ordering {
7400        Ord::cmp(self, &cursor_location.path_key)
7401    }
7402}
7403
7404impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7405where
7406    MBD: MultiBufferDimension + Default,
7407{
7408    fn zero(_: ()) -> Self {
7409        ExcerptDimension(MBD::default())
7410    }
7411
7412    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7413        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7414    }
7415}
7416
7417#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7418struct OutputDimension<T>(T);
7419
7420impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7421    fn eq(&self, other: &T) -> bool {
7422        self.0 == *other
7423    }
7424}
7425
7426impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7427    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7428        self.0.partial_cmp(other)
7429    }
7430}
7431
7432impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7433where
7434    T: ops::Sub<U, Output = R>,
7435{
7436    type Output = R;
7437
7438    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7439        self.0 - other.0
7440    }
7441}
7442
7443impl<R, T, U> ops::Add<U> for OutputDimension<T>
7444where
7445    T: ops::Add<U, Output = R>,
7446{
7447    type Output = OutputDimension<R>;
7448
7449    fn add(self, other: U) -> Self::Output {
7450        OutputDimension(self.0 + other)
7451    }
7452}
7453
7454impl<T, U> AddAssign<U> for OutputDimension<T>
7455where
7456    T: AddAssign<U>,
7457{
7458    fn add_assign(&mut self, other: U) {
7459        self.0 += other;
7460    }
7461}
7462
7463impl<T, U> SubAssign<U> for OutputDimension<T>
7464where
7465    T: SubAssign<U>,
7466{
7467    fn sub_assign(&mut self, other: U) {
7468        self.0 -= other;
7469    }
7470}
7471
7472#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7473struct ExcerptDimension<T>(T);
7474
7475impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7476    fn eq(&self, other: &T) -> bool {
7477        self.0 == *other
7478    }
7479}
7480
7481impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7482    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7483        self.0.partial_cmp(other)
7484    }
7485}
7486
7487impl ExcerptOffset {
7488    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7489        self.0.saturating_sub(other.0)
7490    }
7491}
7492
7493impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7494where
7495    T: ops::Sub<U, Output = R>,
7496{
7497    type Output = R;
7498
7499    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7500        self.0 - other.0
7501    }
7502}
7503
7504impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7505where
7506    T: ops::Add<U, Output = R>,
7507{
7508    type Output = ExcerptDimension<R>;
7509
7510    fn add(self, other: U) -> Self::Output {
7511        ExcerptDimension(self.0 + other)
7512    }
7513}
7514
7515impl<T, U> AddAssign<U> for ExcerptDimension<T>
7516where
7517    T: AddAssign<U>,
7518{
7519    fn add_assign(&mut self, other: U) {
7520        self.0 += other;
7521    }
7522}
7523
7524impl<T, U> SubAssign<U> for ExcerptDimension<T>
7525where
7526    T: SubAssign<U>,
7527{
7528    fn sub_assign(&mut self, other: U) {
7529        self.0 -= other;
7530    }
7531}
7532
7533impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7534    fn zero(_: ()) -> Self {
7535        MultiBufferOffset::ZERO
7536    }
7537
7538    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7539        *self += summary.output.len;
7540    }
7541}
7542
7543impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7544    for ExcerptDimension<MBD>
7545where
7546    MBD: MultiBufferDimension + Ord,
7547{
7548    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7549        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7550    }
7551}
7552
7553impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7554    for ExcerptDimension<MBD>
7555where
7556    MBD: MultiBufferDimension + Ord,
7557{
7558    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7559        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7560    }
7561}
7562
7563impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7564    for ExcerptDimension<MBD>
7565{
7566    fn zero(_: ()) -> Self {
7567        ExcerptDimension(MBD::default())
7568    }
7569
7570    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7571        self.0.add_mb_text_summary(&summary.input)
7572    }
7573}
7574
7575impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7576    for OutputDimension<MBD>
7577where
7578    MBD: MultiBufferDimension + Ord,
7579{
7580    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7581        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7582    }
7583}
7584
7585impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7586    for OutputDimension<MBD>
7587{
7588    fn zero(_: ()) -> Self {
7589        OutputDimension(MBD::default())
7590    }
7591
7592    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7593        self.0.add_mb_text_summary(&summary.output)
7594    }
7595}
7596
7597impl MultiBufferRows<'_> {
7598    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7599        self.point = Point::new(row, 0);
7600        self.cursor.seek(&self.point);
7601    }
7602}
7603
7604impl Iterator for MultiBufferRows<'_> {
7605    type Item = RowInfo;
7606
7607    fn next(&mut self) -> Option<Self::Item> {
7608        if self.is_empty && self.point.row == 0 {
7609            self.point += Point::new(1, 0);
7610            return Some(RowInfo {
7611                buffer_id: None,
7612                buffer_row: Some(0),
7613                multibuffer_row: Some(MultiBufferRow(0)),
7614                diff_status: None,
7615                expand_info: None,
7616                wrapped_buffer_row: None,
7617            });
7618        }
7619
7620        let mut region = self.cursor.region()?.clone();
7621        dbg!("REGION");
7622        while self.point >= region.range.end {
7623            self.cursor.next();
7624            if let Some(next_region) = self.cursor.region() {
7625                region = next_region.clone();
7626            } else if dbg!(self.point) == dbg!(self.cursor.diff_transforms.end().output_dimension.0)
7627            {
7628                let multibuffer_row = MultiBufferRow(self.point.row);
7629                let last_excerpt = self
7630                    .cursor
7631                    .excerpts
7632                    .item()
7633                    .or(self.cursor.excerpts.prev_item())?;
7634                let buffer_snapshot = last_excerpt.buffer_snapshot(self.cursor.snapshot);
7635                let last_row = last_excerpt.range.context.end.to_point(buffer_snapshot).row;
7636
7637                let first_row = last_excerpt
7638                    .range
7639                    .context
7640                    .start
7641                    .to_point(buffer_snapshot)
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 < buffer_snapshot.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_range: last_excerpt.range.context.clone(),
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_range: region.excerpt.range.context.clone(),
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                    self.snapshot,
7764                );
7765            } else {
7766                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7767                    (self.excerpt_offset_range.start - excerpt_start)
7768                        ..(self.excerpt_offset_range.end - excerpt_start),
7769                    self.language_aware,
7770                    self.snapshot,
7771                ));
7772            }
7773        } else {
7774            self.excerpt_chunks = None;
7775        }
7776    }
7777
7778    #[ztracing::instrument(skip_all)]
7779    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7780        loop {
7781            if self.excerpt_offset_range.is_empty() {
7782                return None;
7783            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7784                self.excerpt_offset_range.start += chunk.text.len();
7785                return Some(chunk);
7786            } else {
7787                self.excerpts.next();
7788                let excerpt = self.excerpts.item()?;
7789                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7790                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7791                    self.language_aware,
7792                    self.snapshot,
7793                ));
7794            }
7795        }
7796    }
7797}
7798
7799impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7800    type Item = &'a str;
7801
7802    fn next(&mut self) -> Option<Self::Item> {
7803        let mut region = self.cursor.region()?;
7804        if self.offset == region.range.start {
7805            self.cursor.prev();
7806            region = self.cursor.region()?;
7807            let start_overshoot = self.start.saturating_sub(region.range.start);
7808            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7809                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7810            ));
7811        }
7812
7813        if self.offset == region.range.end && region.has_trailing_newline {
7814            self.offset -= 1;
7815            Some("\n")
7816        } else {
7817            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7818            self.offset -= chunk.len();
7819            Some(chunk)
7820        }
7821    }
7822}
7823
7824impl<'a> Iterator for MultiBufferChunks<'a> {
7825    type Item = Chunk<'a>;
7826
7827    #[ztracing::instrument(skip_all)]
7828    fn next(&mut self) -> Option<Chunk<'a>> {
7829        if self.range.start >= self.range.end {
7830            return None;
7831        }
7832        if self.range.start == self.diff_transforms.end().0 {
7833            self.diff_transforms.next();
7834        }
7835
7836        let diff_transform_start = self.diff_transforms.start().0;
7837        let diff_transform_end = self.diff_transforms.end().0;
7838        debug_assert!(
7839            self.range.start < diff_transform_end,
7840            "{:?} < {:?} of ({1:?}..{2:?})",
7841            self.range.start,
7842            diff_transform_end,
7843            diff_transform_start
7844        );
7845
7846        let diff_transform = self.diff_transforms.item()?;
7847        match diff_transform {
7848            DiffTransform::BufferContent { .. } => {
7849                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7850                    chunk
7851                } else {
7852                    let chunk = self.next_excerpt_chunk().unwrap();
7853                    self.buffer_chunk.insert(chunk)
7854                };
7855
7856                let chunk_end = self.range.start + chunk.text.len();
7857                let diff_transform_end = diff_transform_end.min(self.range.end);
7858
7859                if diff_transform_end < chunk_end {
7860                    let split_idx = diff_transform_end - self.range.start;
7861                    let (before, after) = chunk.text.split_at(split_idx);
7862                    self.range.start = diff_transform_end;
7863                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7864                    let chars = chunk.chars & mask;
7865                    let tabs = chunk.tabs & mask;
7866                    let newlines = chunk.newlines & mask;
7867
7868                    chunk.text = after;
7869                    chunk.chars = chunk.chars >> split_idx;
7870                    chunk.tabs = chunk.tabs >> split_idx;
7871                    chunk.newlines = chunk.newlines >> split_idx;
7872
7873                    Some(Chunk {
7874                        text: before,
7875                        chars,
7876                        tabs,
7877                        newlines,
7878                        ..chunk.clone()
7879                    })
7880                } else {
7881                    self.range.start = chunk_end;
7882                    self.buffer_chunk.take()
7883                }
7884            }
7885            DiffTransform::DeletedHunk {
7886                buffer_id,
7887                base_text_byte_range,
7888                has_trailing_newline,
7889                ..
7890            } => {
7891                let base_text_start =
7892                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7893                let base_text_end =
7894                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7895                let base_text_end = base_text_end.min(base_text_byte_range.end);
7896
7897                let mut chunks = if let Some((_, mut chunks)) = self
7898                    .diff_base_chunks
7899                    .take()
7900                    .filter(|(id, _)| id == buffer_id)
7901                {
7902                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7903                    {
7904                        chunks.seek(base_text_start..base_text_end);
7905                    }
7906                    chunks
7907                } else {
7908                    let base_buffer = &self.snapshot.diffs.get(buffer_id)?.base_text();
7909                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7910                };
7911
7912                let chunk = if let Some(chunk) = chunks.next() {
7913                    self.range.start += chunk.text.len();
7914                    self.diff_base_chunks = Some((*buffer_id, chunks));
7915                    chunk
7916                } else {
7917                    debug_assert!(has_trailing_newline);
7918                    self.range.start += "\n".len();
7919                    Chunk {
7920                        text: "\n",
7921                        chars: 1u128,
7922                        newlines: 1u128,
7923                        ..Default::default()
7924                    }
7925                };
7926                Some(chunk)
7927            }
7928        }
7929    }
7930}
7931
7932impl MultiBufferBytes<'_> {
7933    fn consume(&mut self, len: usize) {
7934        self.range.start += len;
7935        self.chunk = &self.chunk[len..];
7936
7937        if !self.range.is_empty() && self.chunk.is_empty() {
7938            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7939                self.chunk = chunk;
7940            } else if self.has_trailing_newline {
7941                self.has_trailing_newline = false;
7942                self.chunk = b"\n";
7943            } else {
7944                self.cursor.next();
7945                if let Some(region) = self.cursor.region() {
7946                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7947                        region.buffer_range.start
7948                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7949                                .min(region.buffer_range.end),
7950                    );
7951                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7952                    self.excerpt_bytes = Some(excerpt_bytes);
7953                    self.has_trailing_newline =
7954                        region.has_trailing_newline && self.range.end >= region.range.end;
7955                    if self.chunk.is_empty() && self.has_trailing_newline {
7956                        self.has_trailing_newline = false;
7957                        self.chunk = b"\n";
7958                    }
7959                }
7960            }
7961        }
7962    }
7963}
7964
7965impl<'a> Iterator for MultiBufferBytes<'a> {
7966    type Item = &'a [u8];
7967
7968    fn next(&mut self) -> Option<Self::Item> {
7969        let chunk = self.chunk;
7970        if chunk.is_empty() {
7971            None
7972        } else {
7973            self.consume(chunk.len());
7974            Some(chunk)
7975        }
7976    }
7977}
7978
7979impl io::Read for MultiBufferBytes<'_> {
7980    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7981        let len = cmp::min(buf.len(), self.chunk.len());
7982        buf[..len].copy_from_slice(&self.chunk[..len]);
7983        if len > 0 {
7984            self.consume(len);
7985        }
7986        Ok(len)
7987    }
7988}
7989
7990impl io::Read for ReversedMultiBufferBytes<'_> {
7991    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7992        let len = cmp::min(buf.len(), self.chunk.len());
7993        buf[..len].copy_from_slice(&self.chunk[..len]);
7994        buf[..len].reverse();
7995        if len > 0 {
7996            self.range.end -= len;
7997            self.chunk = &self.chunk[..self.chunk.len() - len];
7998            if !self.range.is_empty()
7999                && self.chunk.is_empty()
8000                && let Some(chunk) = self.chunks.next()
8001            {
8002                self.chunk = chunk.as_bytes();
8003            }
8004        }
8005        Ok(len)
8006    }
8007}
8008
8009impl<'a> Iterator for ExcerptChunks<'a> {
8010    type Item = Chunk<'a>;
8011
8012    fn next(&mut self) -> Option<Self::Item> {
8013        if let Some(chunk) = self.content_chunks.next() {
8014            return Some(chunk);
8015        }
8016
8017        if self.has_footer {
8018            let text = "\n";
8019            let chars = 0b1;
8020            let newlines = 0b1;
8021            self.has_footer = false;
8022            return Some(Chunk {
8023                text,
8024                chars,
8025                newlines,
8026                ..Default::default()
8027            });
8028        }
8029
8030        None
8031    }
8032}
8033
8034impl ToOffset for Point {
8035    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8036        snapshot.point_to_offset(*self)
8037    }
8038    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8039        snapshot.point_to_offset_utf16(*self)
8040    }
8041}
8042
8043impl ToOffset for MultiBufferOffset {
8044    #[track_caller]
8045    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8046        assert!(
8047            *self <= snapshot.len(),
8048            "offset {} is greater than the snapshot.len() {}",
8049            self.0,
8050            snapshot.len().0,
8051        );
8052        *self
8053    }
8054    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8055        snapshot.offset_to_offset_utf16(*self)
8056    }
8057}
8058
8059impl ToOffset for MultiBufferOffsetUtf16 {
8060    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8061        snapshot.offset_utf16_to_offset(*self)
8062    }
8063
8064    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8065        *self
8066    }
8067}
8068
8069impl ToOffset for PointUtf16 {
8070    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8071        snapshot.point_utf16_to_offset(*self)
8072    }
8073    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8074        snapshot.point_utf16_to_offset_utf16(*self)
8075    }
8076}
8077
8078impl ToPoint for MultiBufferOffset {
8079    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8080        snapshot.offset_to_point(*self)
8081    }
8082    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8083        snapshot.offset_to_point_utf16(*self)
8084    }
8085}
8086
8087impl ToPoint for Point {
8088    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8089        *self
8090    }
8091    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8092        snapshot.point_to_point_utf16(*self)
8093    }
8094}
8095
8096impl ToPoint for PointUtf16 {
8097    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8098        snapshot.point_utf16_to_point(*self)
8099    }
8100    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8101        *self
8102    }
8103}
8104
8105#[cfg(debug_assertions)]
8106pub mod debug {
8107    use super::*;
8108
8109    pub trait ToMultiBufferDebugRanges {
8110        fn to_multi_buffer_debug_ranges(
8111            &self,
8112            snapshot: &MultiBufferSnapshot,
8113        ) -> Vec<Range<MultiBufferOffset>>;
8114    }
8115
8116    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8117        fn to_multi_buffer_debug_ranges(
8118            &self,
8119            snapshot: &MultiBufferSnapshot,
8120        ) -> Vec<Range<MultiBufferOffset>> {
8121            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8122        }
8123    }
8124
8125    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8126        fn to_multi_buffer_debug_ranges(
8127            &self,
8128            snapshot: &MultiBufferSnapshot,
8129        ) -> Vec<Range<MultiBufferOffset>> {
8130            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8131                .to_multi_buffer_debug_ranges(snapshot)
8132        }
8133    }
8134
8135    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8136        fn to_multi_buffer_debug_ranges(
8137            &self,
8138            snapshot: &MultiBufferSnapshot,
8139        ) -> Vec<Range<MultiBufferOffset>> {
8140            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8141        }
8142    }
8143
8144    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8145        fn to_multi_buffer_debug_ranges(
8146            &self,
8147            snapshot: &MultiBufferSnapshot,
8148        ) -> Vec<Range<MultiBufferOffset>> {
8149            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8150        }
8151    }
8152
8153    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8154        fn to_multi_buffer_debug_ranges(
8155            &self,
8156            snapshot: &MultiBufferSnapshot,
8157        ) -> Vec<Range<MultiBufferOffset>> {
8158            self.iter()
8159                .map(|item| {
8160                    let offset = item.to_offset(snapshot);
8161                    offset..offset
8162                })
8163                .collect()
8164        }
8165    }
8166
8167    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8168        fn to_multi_buffer_debug_ranges(
8169            &self,
8170            snapshot: &MultiBufferSnapshot,
8171        ) -> Vec<Range<MultiBufferOffset>> {
8172            self.iter()
8173                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8174                .collect()
8175        }
8176    }
8177}