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: Option<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: None,
 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_for_buffer(excerpt.buffer_id)),
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_for_buffer(excerpt.buffer_id)),
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.text_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.text_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.text_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
1970            .buffers
1971            .get(&anchor.text_anchor.buffer_id)?
1972            .buffer
1973            .clone();
1974        Some((buffer, anchor.text_anchor()))
1975    }
1976
1977    fn on_buffer_event(
1978        &mut self,
1979        buffer: Entity<Buffer>,
1980        event: &language::BufferEvent,
1981        cx: &mut Context<Self>,
1982    ) {
1983        use language::BufferEvent;
1984        let buffer_id = buffer.read(cx).remote_id();
1985        cx.emit(match event {
1986            BufferEvent::Edited => Event::Edited {
1987                edited_buffer: Some(buffer),
1988            },
1989            BufferEvent::DirtyChanged => Event::DirtyChanged,
1990            BufferEvent::Saved => Event::Saved,
1991            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1992            BufferEvent::Reloaded => Event::Reloaded,
1993            BufferEvent::LanguageChanged(has_language) => {
1994                Event::LanguageChanged(buffer_id, *has_language)
1995            }
1996            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1997            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1998            BufferEvent::CapabilityChanged => {
1999                self.capability = buffer.read(cx).capability();
2000                return;
2001            }
2002            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2003        });
2004    }
2005
2006    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2007        let diff = diff.read(cx);
2008        let buffer_id = diff.buffer_id;
2009        let diff = DiffStateSnapshot {
2010            diff: diff.snapshot(cx),
2011            main_buffer: None,
2012        };
2013        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2014    }
2015
2016    fn inverted_buffer_diff_language_changed(
2017        &mut self,
2018        diff: Entity<BufferDiff>,
2019        main_buffer: Entity<language::Buffer>,
2020        cx: &mut Context<Self>,
2021    ) {
2022        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2023        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2024        let diff = diff.read(cx);
2025        let diff = DiffStateSnapshot {
2026            diff: diff.snapshot(cx),
2027            main_buffer: Some(main_buffer_snapshot),
2028        };
2029        self.snapshot
2030            .get_mut()
2031            .diffs
2032            .insert(base_text_buffer_id, diff);
2033    }
2034
2035    fn buffer_diff_changed(
2036        &mut self,
2037        diff: Entity<BufferDiff>,
2038        range: Range<text::Anchor>,
2039        cx: &mut Context<Self>,
2040    ) {
2041        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2042            return;
2043        };
2044        let snapshot = self.sync_mut(cx);
2045
2046        let diff = diff.read(cx);
2047        let buffer_id = diff.buffer_id;
2048
2049        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2050            return;
2051        };
2052        let new_diff = DiffStateSnapshot {
2053            diff: diff.snapshot(cx),
2054            main_buffer: None,
2055        };
2056        let base_text_changed = snapshot
2057            .diffs
2058            .get(&buffer_id)
2059            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2060        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2061
2062        let buffer = buffer.read(cx);
2063        let diff_change_range = range.to_offset(buffer);
2064
2065        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2066        let edits = Self::sync_diff_transforms(
2067            snapshot,
2068            excerpt_edits,
2069            DiffChangeKind::DiffUpdated {
2070                base_changed: base_text_changed,
2071            },
2072        );
2073        if !edits.is_empty() {
2074            self.subscriptions.publish(edits);
2075        }
2076        cx.emit(Event::Edited {
2077            edited_buffer: None,
2078        });
2079    }
2080
2081    fn inverted_buffer_diff_changed(
2082        &mut self,
2083        diff: Entity<BufferDiff>,
2084        main_buffer: Entity<language::Buffer>,
2085        diff_change_range: Option<Range<usize>>,
2086        cx: &mut Context<Self>,
2087    ) {
2088        let snapshot = self.sync_mut(cx);
2089
2090        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2091        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2092            return;
2093        };
2094
2095        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2096        let diff = diff.read(cx);
2097        let new_diff = DiffStateSnapshot {
2098            diff: diff.snapshot(cx),
2099            main_buffer: Some(main_buffer_snapshot),
2100        };
2101        snapshot
2102            .diffs
2103            .insert_or_replace(base_text_buffer_id, new_diff);
2104
2105        let Some(diff_change_range) = diff_change_range else {
2106            return;
2107        };
2108
2109        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2110        let edits = Self::sync_diff_transforms(
2111            snapshot,
2112            excerpt_edits,
2113            DiffChangeKind::DiffUpdated {
2114                // We don't read this field for inverted diffs.
2115                base_changed: false,
2116            },
2117        );
2118        if !edits.is_empty() {
2119            self.subscriptions.publish(edits);
2120        }
2121        cx.emit(Event::Edited {
2122            edited_buffer: None,
2123        });
2124    }
2125
2126    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2127        self.buffers.values().map(|state| state.buffer.clone())
2128    }
2129
2130    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2131        self.all_buffers_iter().collect()
2132    }
2133
2134    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2135        self.buffers.keys().copied()
2136    }
2137
2138    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2139        self.all_buffer_ids_iter().collect()
2140    }
2141
2142    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2143        self.buffers
2144            .get(&buffer_id)
2145            .map(|state| state.buffer.clone())
2146    }
2147
2148    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2149        self.point_to_buffer_offset(point, cx)
2150            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2151    }
2152
2153    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2154        let snapshot = self.snapshot(cx);
2155        let buffer = snapshot
2156            .excerpts
2157            .first()
2158            .map(|excerpt| excerpt.buffer(self));
2159        buffer
2160            .map(|buffer| {
2161                let buffer = buffer.read(cx);
2162                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2163            })
2164            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2165    }
2166
2167    pub fn language_settings_at<'a, T: ToOffset>(
2168        &'a self,
2169        point: T,
2170        cx: &'a App,
2171    ) -> Cow<'a, LanguageSettings> {
2172        let mut language = None;
2173        let mut file = None;
2174        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2175            let buffer = buffer.read(cx);
2176            language = buffer.language_at(offset);
2177            file = buffer.file();
2178        }
2179        language_settings(language.map(|l| l.name()), file, cx)
2180    }
2181
2182    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2183        self.buffers.values().for_each(|state| f(&state.buffer))
2184    }
2185
2186    pub fn explicit_title(&self) -> Option<&str> {
2187        self.title.as_deref()
2188    }
2189
2190    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2191        if let Some(title) = self.title.as_ref() {
2192            return title.into();
2193        }
2194
2195        if let Some(buffer) = self.as_singleton() {
2196            let buffer = buffer.read(cx);
2197
2198            if let Some(file) = buffer.file() {
2199                return file.file_name(cx).into();
2200            }
2201
2202            if let Some(title) = self.buffer_content_title(buffer) {
2203                return title;
2204            }
2205        };
2206
2207        "untitled".into()
2208    }
2209
2210    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2211        let mut is_leading_whitespace = true;
2212        let mut count = 0;
2213        let mut prev_was_space = false;
2214        let mut title = String::new();
2215
2216        for ch in buffer.snapshot().chars() {
2217            if is_leading_whitespace && ch.is_whitespace() {
2218                continue;
2219            }
2220
2221            is_leading_whitespace = false;
2222
2223            if ch == '\n' || count >= 40 {
2224                break;
2225            }
2226
2227            if ch.is_whitespace() {
2228                if !prev_was_space {
2229                    title.push(' ');
2230                    count += 1;
2231                    prev_was_space = true;
2232                }
2233            } else {
2234                title.push(ch);
2235                count += 1;
2236                prev_was_space = false;
2237            }
2238        }
2239
2240        let title = title.trim_end().to_string();
2241
2242        if title.is_empty() {
2243            return None;
2244        }
2245
2246        Some(title.into())
2247    }
2248
2249    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2250        self.title = Some(title);
2251        cx.notify();
2252    }
2253
2254    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2255    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2256        for buffer_state in self.buffers.values() {
2257            buffer_state
2258                .buffer
2259                .update(cx, |buffer, _cx| buffer.refresh_preview());
2260        }
2261    }
2262
2263    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2264    pub fn preserve_preview(&self, cx: &App) -> bool {
2265        self.buffers
2266            .values()
2267            .all(|state| state.buffer.read(cx).preserve_preview())
2268    }
2269
2270    #[cfg(any(test, feature = "test-support"))]
2271    pub fn is_parsing(&self, cx: &App) -> bool {
2272        self.as_singleton().unwrap().read(cx).is_parsing()
2273    }
2274
2275    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2276        let buffer_id = diff.read(cx).buffer_id;
2277
2278        if let Some(existing_diff) = self.diff_for(buffer_id)
2279            && diff.entity_id() == existing_diff.entity_id()
2280        {
2281            return;
2282        }
2283
2284        self.buffer_diff_changed(
2285            diff.clone(),
2286            text::Anchor::min_max_range_for_buffer(buffer_id),
2287            cx,
2288        );
2289        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2290    }
2291
2292    pub fn add_inverted_diff(
2293        &mut self,
2294        diff: Entity<BufferDiff>,
2295        main_buffer: Entity<language::Buffer>,
2296        cx: &mut Context<Self>,
2297    ) {
2298        let snapshot = diff.read(cx).base_text(cx);
2299        let base_text_buffer_id = snapshot.remote_id();
2300        let diff_change_range = 0..snapshot.len();
2301        self.snapshot.get_mut().has_inverted_diff = true;
2302        self.inverted_buffer_diff_changed(
2303            diff.clone(),
2304            main_buffer.clone(),
2305            Some(diff_change_range),
2306            cx,
2307        );
2308        self.diffs.insert(
2309            base_text_buffer_id,
2310            DiffState::new_inverted(diff, main_buffer, cx),
2311        );
2312    }
2313
2314    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2315        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2316    }
2317
2318    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2319        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2320    }
2321
2322    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2323        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2324    }
2325
2326    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2327        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2328        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2329    }
2330
2331    pub fn all_diff_hunks_expanded(&self) -> bool {
2332        self.snapshot.borrow().all_diff_hunks_expanded
2333    }
2334
2335    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2336        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2337        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2338    }
2339
2340    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2341        self.snapshot.get_mut().show_deleted_hunks = show;
2342
2343        self.sync_mut(cx);
2344
2345        let old_len = self.snapshot.borrow().len();
2346
2347        let ranges = std::iter::once((Point::zero()..Point::MAX, Anchor::Max));
2348        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2349
2350        let new_len = self.snapshot.borrow().len();
2351
2352        self.subscriptions.publish(vec![Edit {
2353            old: MultiBufferOffset(0)..old_len,
2354            new: MultiBufferOffset(0)..new_len,
2355        }]);
2356
2357        cx.emit(Event::DiffHunksToggled);
2358        cx.emit(Event::Edited {
2359            edited_buffer: None,
2360        });
2361    }
2362
2363    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2364        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2365    }
2366
2367    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2368        self.read(cx)
2369            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2370            .nth(1)
2371            .is_some()
2372    }
2373
2374    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2375        let snapshot = self.read(cx);
2376        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2377        let offset_range = range.to_offset(&snapshot);
2378        cursor.seek(&offset_range.start, Bias::Left);
2379        while let Some(item) = cursor.item() {
2380            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2381                break;
2382            }
2383            if item.hunk_info().is_some() {
2384                return true;
2385            }
2386            cursor.next();
2387        }
2388        false
2389    }
2390
2391    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2392        let snapshot = self.read(cx);
2393        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2394        for range in ranges {
2395            let range = range.to_point(&snapshot);
2396            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2397            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2398                .min(snapshot.len());
2399            cursor.seek(&start, Bias::Right);
2400            while let Some(item) = cursor.item() {
2401                if *cursor.start() >= end {
2402                    break;
2403                }
2404                if item.hunk_info().is_some() {
2405                    return true;
2406                }
2407                cursor.next();
2408            }
2409        }
2410        false
2411    }
2412
2413    pub fn expand_or_collapse_diff_hunks_inner(
2414        &mut self,
2415        // second element is the end of the last excerpt that should be considered for this range
2416        // (or Anchor::Max to opt out)
2417        ranges: impl IntoIterator<Item = (Range<Point>, Anchor)>,
2418        expand: bool,
2419        cx: &mut Context<Self>,
2420    ) -> Vec<Edit<MultiBufferOffset>> {
2421        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2422            return Vec::new();
2423        }
2424        self.sync_mut(cx);
2425        let mut snapshot = self.snapshot.get_mut();
2426        let mut excerpt_edits = Vec::new();
2427        let mut last_hunk_row = None;
2428        for (range, excerpt_end) in ranges {
2429            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2430                if diff_hunk
2431                    .multi_buffer_range()
2432                    .end
2433                    .cmp(&excerpt_end, &snapshot)
2434                    .is_gt()
2435                {
2436                    continue;
2437                }
2438                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2439                    continue;
2440                }
2441                let range = diff_hunk.multi_buffer_range();
2442                let start = snapshot.excerpt_offset_for_anchor(&range.start);
2443                let end = snapshot.excerpt_offset_for_anchor(&range.end);
2444                last_hunk_row = Some(diff_hunk.row_range.start);
2445                excerpt_edits.push(text::Edit {
2446                    old: start..end,
2447                    new: start..end,
2448                });
2449            }
2450        }
2451
2452        Self::sync_diff_transforms(
2453            &mut snapshot,
2454            excerpt_edits,
2455            DiffChangeKind::ExpandOrCollapseHunks { expand },
2456        )
2457    }
2458
2459    pub fn expand_or_collapse_diff_hunks(
2460        &mut self,
2461        ranges: Vec<Range<Anchor>>,
2462        expand: bool,
2463        cx: &mut Context<Self>,
2464    ) {
2465        let snapshot = self.snapshot.borrow().clone();
2466        let ranges = ranges.iter().map(move |range| {
2467            let excerpt_end = snapshot
2468                .excerpt_containing(range.end..range.end)
2469                .map(|excerpt| excerpt.end_anchor().into())
2470                .unwrap_or(Anchor::Max);
2471            let range = range.to_point(&snapshot);
2472            let mut peek_end = range.end;
2473            if range.end.row < snapshot.max_row().0 {
2474                peek_end = Point::new(range.end.row + 1, 0);
2475            };
2476            (range.start..peek_end, excerpt_end)
2477        });
2478        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2479        if !edits.is_empty() {
2480            self.subscriptions.publish(edits);
2481        }
2482        cx.emit(Event::DiffHunksToggled);
2483        cx.emit(Event::Edited {
2484            edited_buffer: None,
2485        });
2486    }
2487
2488    #[ztracing::instrument(skip_all)]
2489    fn sync(&self, cx: &App) {
2490        let changed = self.buffer_changed_since_sync.replace(false);
2491        if !changed {
2492            return;
2493        }
2494        let edits = Self::sync_from_buffer_changes(
2495            &mut self.snapshot.borrow_mut(),
2496            &self.buffers,
2497            &self.diffs,
2498            cx,
2499        );
2500        if !edits.is_empty() {
2501            self.subscriptions.publish(edits);
2502        }
2503    }
2504
2505    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2506        let snapshot = self.snapshot.get_mut();
2507        let changed = self.buffer_changed_since_sync.replace(false);
2508        if !changed {
2509            return snapshot;
2510        }
2511        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2512        dbg!(&edits);
2513
2514        if !edits.is_empty() {
2515            self.subscriptions.publish(edits);
2516        }
2517
2518        snapshot
2519    }
2520
2521    fn sync_from_buffer_changes(
2522        snapshot: &mut MultiBufferSnapshot,
2523        buffers: &BTreeMap<BufferId, BufferState>,
2524        diffs: &HashMap<BufferId, DiffState>,
2525        cx: &App,
2526    ) -> Vec<Edit<MultiBufferOffset>> {
2527        let MultiBufferSnapshot {
2528            excerpts,
2529            diffs: buffer_diff,
2530            buffers: buffer_snapshots,
2531            path_keys_by_index: _,
2532            diff_transforms: _,
2533            non_text_state_update_count,
2534            edit_count,
2535            is_dirty,
2536            has_deleted_file,
2537            has_conflict,
2538            has_inverted_diff: _,
2539            singleton: _,
2540            trailing_excerpt_update_count: _,
2541            all_diff_hunks_expanded: _,
2542            show_deleted_hunks: _,
2543            use_extended_diff_range: _,
2544            show_headers: _,
2545        } = snapshot;
2546        *is_dirty = false;
2547        *has_deleted_file = false;
2548        *has_conflict = false;
2549
2550        if !diffs.is_empty() {
2551            let mut diffs_to_add = Vec::new();
2552            for (id, diff) in diffs {
2553                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2554                // and use the diff hunk base text ranges to compute diff transforms.
2555                // Those base text ranges are usize, so make sure if the base text changed
2556                // we also update the diff snapshot so that we don't use stale offsets
2557                if buffer_diff.get(id).is_none_or(|existing_diff| {
2558                    if existing_diff.main_buffer.is_none() {
2559                        return false;
2560                    }
2561                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2562                    base_text.remote_id() != existing_diff.base_text().remote_id()
2563                        || base_text
2564                            .version()
2565                            .changed_since(existing_diff.base_text().version())
2566                }) {
2567                    if diffs_to_add.capacity() == 0 {
2568                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2569                        // meaning re-allocations will be fairly expensive
2570                        diffs_to_add.reserve(diffs.len());
2571                    }
2572                    diffs_to_add.push((*id, diff.snapshot(cx)));
2573                }
2574            }
2575            buffer_diff.extend(diffs_to_add);
2576        }
2577
2578        let mut paths_to_edit = Vec::new();
2579        let mut non_text_state_updated = false;
2580        let mut edited = false;
2581        for buffer_state in buffers.values() {
2582            let buffer = buffer_state.buffer.read(cx);
2583            let last_snapshot = buffer_snapshots
2584                .get(&buffer.remote_id())
2585                .expect("each buffer should have a snapshot");
2586            let current_version = buffer.version();
2587            let non_text_state_update_count = buffer.non_text_state_update_count();
2588
2589            let buffer_edited =
2590                current_version.changed_since(last_snapshot.buffer_snapshot.version());
2591            dbg!(
2592                &current_version,
2593                last_snapshot.buffer_snapshot.version().clone()
2594            );
2595            let buffer_non_text_state_updated = non_text_state_update_count
2596                > last_snapshot.buffer_snapshot.non_text_state_update_count();
2597            if buffer_edited || buffer_non_text_state_updated {
2598                paths_to_edit.push((
2599                    last_snapshot.path_key.clone(),
2600                    buffer_state.buffer.clone(),
2601                    if buffer_edited {
2602                        Some(last_snapshot.buffer_snapshot.version().clone())
2603                    } else {
2604                        None
2605                    },
2606                ));
2607            }
2608
2609            edited |= buffer_edited;
2610            non_text_state_updated |= buffer_non_text_state_updated;
2611            *is_dirty |= buffer.is_dirty();
2612            *has_deleted_file |= buffer
2613                .file()
2614                .is_some_and(|file| file.disk_state().is_deleted());
2615            *has_conflict |= buffer.has_conflict();
2616        }
2617        if edited {
2618            *edit_count += 1;
2619        }
2620        if non_text_state_updated {
2621            *non_text_state_update_count += 1;
2622        }
2623
2624        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path.clone());
2625
2626        let mut edits = Vec::new();
2627        let mut new_excerpts = SumTree::default();
2628        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2629
2630        for (path, buffer, prev_version) in paths_to_edit {
2631            dbg!(&prev_version, buffer.read(cx).version());
2632            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2633            let old_excerpt = cursor.item().unwrap();
2634            let buffer = buffer.read(cx);
2635            let buffer_id = buffer.remote_id();
2636
2637            buffer_snapshots.insert(
2638                buffer_id,
2639                BufferStateSnapshot {
2640                    path_key: path.clone(),
2641                    buffer_snapshot: buffer.snapshot(),
2642                },
2643            );
2644
2645            let new_excerpt = if let Some(prev_version) = prev_version {
2646                edits.extend(
2647                    buffer
2648                        .edits_since_in_range::<usize>(
2649                            &prev_version,
2650                            dbg!(old_excerpt.range.context.clone()),
2651                        )
2652                        .map(|edit| {
2653                            dbg!(&edit);
2654                            let excerpt_old_start = cursor.start().len();
2655                            let excerpt_new_start =
2656                                ExcerptDimension(new_excerpts.summary().text.len);
2657                            let old_start = excerpt_old_start + edit.old.start;
2658                            let old_end = excerpt_old_start + edit.old.end;
2659                            let new_start = excerpt_new_start + edit.new.start;
2660                            let new_end = excerpt_new_start + edit.new.end;
2661                            Edit {
2662                                old: old_start..old_end,
2663                                new: new_start..new_end,
2664                            }
2665                        }),
2666                );
2667
2668                Excerpt::new(
2669                    path,
2670                    old_excerpt.path_key_index,
2671                    &buffer.snapshot(),
2672                    old_excerpt.range.clone(),
2673                    old_excerpt.has_trailing_newline,
2674                )
2675            } else {
2676                old_excerpt.clone()
2677            };
2678
2679            new_excerpts.push(new_excerpt, ());
2680            cursor.next();
2681        }
2682        new_excerpts.append(cursor.suffix(), ());
2683
2684        drop(cursor);
2685        *excerpts = new_excerpts;
2686
2687        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2688    }
2689
2690    fn sync_diff_transforms(
2691        snapshot: &mut MultiBufferSnapshot,
2692        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2693        change_kind: DiffChangeKind,
2694    ) -> Vec<Edit<MultiBufferOffset>> {
2695        dbg!(&excerpt_edits);
2696        if excerpt_edits.is_empty() {
2697            return vec![];
2698        }
2699
2700        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2701        let mut old_diff_transforms = snapshot
2702            .diff_transforms
2703            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2704        let mut new_diff_transforms = SumTree::default();
2705        let mut old_expanded_hunks = HashSet::default();
2706        let mut output_edits = Vec::new();
2707        let mut output_delta = 0_isize;
2708        let mut at_transform_boundary = true;
2709        let mut end_of_current_insert = None;
2710
2711        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2712        while let Some(edit) = excerpt_edits.next() {
2713            excerpts.seek_forward(&edit.new.start, Bias::Right);
2714            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2715                excerpts.prev();
2716            }
2717
2718            // Keep any transforms that are before the edit.
2719            if at_transform_boundary {
2720                at_transform_boundary = false;
2721                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2722                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2723                if let Some(transform) = old_diff_transforms.item()
2724                    && old_diff_transforms.end().0 == edit.old.start
2725                    && old_diff_transforms.start().0 < edit.old.start
2726                {
2727                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2728                    old_diff_transforms.next();
2729                }
2730            }
2731
2732            // Compute the start of the edit in output coordinates.
2733            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2734            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2735            let edit_new_start =
2736                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2737
2738            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2739                &edit,
2740                &mut excerpts,
2741                &mut old_diff_transforms,
2742                &mut new_diff_transforms,
2743                &mut end_of_current_insert,
2744                &mut old_expanded_hunks,
2745                snapshot,
2746                change_kind,
2747            );
2748
2749            // Compute the end of the edit in output coordinates.
2750            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2751            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2752            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2753            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2754            let output_edit = Edit {
2755                old: edit_old_start..edit_old_end,
2756                new: edit_new_start..edit_new_end,
2757            };
2758
2759            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2760            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2761            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2762                output_edits.push(output_edit);
2763            }
2764
2765            // If this is the last edit that intersects the current diff transform,
2766            // then recreate the content up to the end of this transform, to prepare
2767            // for reusing additional slices of the old transforms.
2768            if excerpt_edits
2769                .peek()
2770                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2771            {
2772                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2773                    && match old_diff_transforms.item() {
2774                        Some(DiffTransform::BufferContent {
2775                            inserted_hunk_info: Some(hunk),
2776                            ..
2777                        }) => excerpts.item().is_some_and(|excerpt| {
2778                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2779                                && diff.main_buffer.is_some()
2780                            {
2781                                return true;
2782                            }
2783                            hunk.hunk_start_anchor
2784                                .is_valid(&excerpt.buffer_snapshot(&snapshot))
2785                        }),
2786                        _ => true,
2787                    };
2788
2789                let mut excerpt_offset = edit.new.end;
2790                if !keep_next_old_transform {
2791                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2792                    old_diff_transforms.next();
2793                }
2794
2795                old_expanded_hunks.clear();
2796                Self::push_buffer_content_transform(
2797                    snapshot,
2798                    &mut new_diff_transforms,
2799                    excerpt_offset,
2800                    end_of_current_insert,
2801                );
2802                at_transform_boundary = true;
2803            }
2804        }
2805
2806        // Keep any transforms that are after the last edit.
2807        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2808
2809        // Ensure there's always at least one buffer content transform.
2810        if new_diff_transforms.is_empty() {
2811            new_diff_transforms.push(
2812                DiffTransform::BufferContent {
2813                    summary: Default::default(),
2814                    inserted_hunk_info: None,
2815                },
2816                (),
2817            );
2818        }
2819
2820        drop(old_diff_transforms);
2821        drop(excerpts);
2822        snapshot.diff_transforms = new_diff_transforms;
2823        snapshot.edit_count += 1;
2824
2825        #[cfg(any(test, feature = "test-support"))]
2826        snapshot.check_invariants();
2827        output_edits
2828    }
2829
2830    fn recompute_diff_transforms_for_edit(
2831        edit: &Edit<ExcerptOffset>,
2832        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2833        old_diff_transforms: &mut Cursor<
2834            DiffTransform,
2835            Dimensions<ExcerptOffset, MultiBufferOffset>,
2836        >,
2837        new_diff_transforms: &mut SumTree<DiffTransform>,
2838        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2839        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2840        snapshot: &MultiBufferSnapshot,
2841        change_kind: DiffChangeKind,
2842    ) -> bool {
2843        log::trace!(
2844            "recomputing diff transform for edit {:?} => {:?}",
2845            edit.old.start..edit.old.end,
2846            edit.new.start..edit.new.end
2847        );
2848
2849        // Record which hunks were previously expanded.
2850        while let Some(item) = old_diff_transforms.item() {
2851            if let Some(hunk_info) = item.hunk_info() {
2852                log::trace!(
2853                    "previously expanded hunk at {:?}",
2854                    old_diff_transforms.start()
2855                );
2856                old_expanded_hunks.insert(hunk_info);
2857            }
2858            if old_diff_transforms.end().0 > edit.old.end {
2859                break;
2860            }
2861            old_diff_transforms.next();
2862        }
2863
2864        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2865        // For inverted diffs, hunks are always shown, so we can't skip this.
2866        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2867        if old_expanded_hunks.is_empty()
2868            && change_kind == DiffChangeKind::BufferEdited
2869            && !all_diff_hunks_expanded
2870            && !snapshot.has_inverted_diff
2871        {
2872            return false;
2873        }
2874
2875        // Visit each excerpt that intersects the edit.
2876        let mut did_expand_hunks = false;
2877        while let Some(excerpt) = excerpts.item() {
2878            // Recompute the expanded hunks in the portion of the excerpt that
2879            // intersects the edit.
2880            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2881                let buffer_snapshot = &excerpt.buffer_snapshot(&snapshot);
2882                let excerpt_start = *excerpts.start();
2883                let excerpt_end = excerpt_start + excerpt.text_summary.len;
2884                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer_snapshot);
2885                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2886                let edit_buffer_start =
2887                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
2888                let edit_buffer_end =
2889                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
2890                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2891
2892                if let Some(main_buffer) = &diff.main_buffer {
2893                    for hunk in diff.hunks_intersecting_base_text_range(
2894                        edit_buffer_start..edit_buffer_end,
2895                        main_buffer,
2896                    ) {
2897                        did_expand_hunks = true;
2898                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
2899                        if hunk_buffer_range.start < excerpt_buffer_start {
2900                            log::trace!("skipping hunk that starts before excerpt");
2901                            continue;
2902                        }
2903                        hunk_buffer_range
2904                            .end
2905                            .to_point(&excerpt.buffer_snapshot(&snapshot));
2906                        let hunk_excerpt_start = excerpt_start
2907                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2908                        let hunk_excerpt_end = excerpt_end
2909                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2910                        Self::push_buffer_content_transform(
2911                            snapshot,
2912                            new_diff_transforms,
2913                            hunk_excerpt_start,
2914                            *end_of_current_insert,
2915                        );
2916                        if !hunk_buffer_range.is_empty() {
2917                            let hunk_info = DiffTransformHunkInfo {
2918                                buffer_id: buffer_snapshot.remote_id(),
2919                                hunk_start_anchor: hunk.buffer_range.start,
2920                                hunk_secondary_status: hunk.secondary_status,
2921                                excerpt_end: excerpt.end_anchor(),
2922                                is_logically_deleted: true,
2923                            };
2924                            *end_of_current_insert =
2925                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2926                        }
2927                    }
2928                } else {
2929                    let edit_anchor_range = buffer_snapshot.anchor_before(edit_buffer_start)
2930                        ..buffer_snapshot.anchor_after(edit_buffer_end);
2931                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer_snapshot) {
2932                        if hunk.is_created_file() && !all_diff_hunks_expanded {
2933                            continue;
2934                        }
2935
2936                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer_snapshot);
2937                        if hunk_buffer_range.start < excerpt_buffer_start {
2938                            log::trace!("skipping hunk that starts before excerpt");
2939                            continue;
2940                        }
2941
2942                        let hunk_info = DiffTransformHunkInfo {
2943                            buffer_id: buffer_snapshot.remote_id(),
2944                            hunk_start_anchor: hunk.buffer_range.start,
2945                            hunk_secondary_status: hunk.secondary_status,
2946                            excerpt_end: excerpt.end_anchor(),
2947                            is_logically_deleted: false,
2948                        };
2949
2950                        let hunk_excerpt_start = excerpt_start
2951                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2952                        let hunk_excerpt_end = excerpt_end
2953                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2954
2955                        Self::push_buffer_content_transform(
2956                            snapshot,
2957                            new_diff_transforms,
2958                            hunk_excerpt_start,
2959                            *end_of_current_insert,
2960                        );
2961
2962                        // For every existing hunk, determine if it was previously expanded
2963                        // and if it should currently be expanded.
2964                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2965                        let should_expand_hunk = match &change_kind {
2966                            DiffChangeKind::DiffUpdated { base_changed: true } => {
2967                                was_previously_expanded || all_diff_hunks_expanded
2968                            }
2969                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2970                                let intersects = hunk_buffer_range.is_empty()
2971                                    || hunk_buffer_range.end > edit_buffer_start;
2972                                if *expand {
2973                                    intersects || was_previously_expanded || all_diff_hunks_expanded
2974                                } else {
2975                                    !intersects
2976                                        && (was_previously_expanded || all_diff_hunks_expanded)
2977                                }
2978                            }
2979                            _ => was_previously_expanded || all_diff_hunks_expanded,
2980                        };
2981
2982                        if should_expand_hunk {
2983                            did_expand_hunks = true;
2984                            log::trace!(
2985                                "expanding hunk {:?}",
2986                                hunk_excerpt_start..hunk_excerpt_end,
2987                            );
2988
2989                            if !hunk.diff_base_byte_range.is_empty()
2990                                && hunk_buffer_range.start >= edit_buffer_start
2991                                && hunk_buffer_range.start <= excerpt_buffer_end
2992                                && snapshot.show_deleted_hunks
2993                            {
2994                                let base_text = diff.base_text();
2995                                let mut text_cursor =
2996                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2997                                let mut base_text_summary = text_cursor
2998                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
2999
3000                                let mut has_trailing_newline = false;
3001                                if base_text_summary.last_line_chars > 0 {
3002                                    base_text_summary += TextSummary::newline();
3003                                    has_trailing_newline = true;
3004                                }
3005
3006                                new_diff_transforms.push(
3007                                    DiffTransform::DeletedHunk {
3008                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3009                                        summary: base_text_summary,
3010                                        buffer_id: buffer_snapshot.remote_id(),
3011                                        hunk_info,
3012                                        has_trailing_newline,
3013                                    },
3014                                    (),
3015                                );
3016                            }
3017
3018                            if !hunk_buffer_range.is_empty() {
3019                                *end_of_current_insert =
3020                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3021                            }
3022                        }
3023                    }
3024                }
3025            }
3026
3027            if excerpts.end() <= edit.new.end {
3028                excerpts.next();
3029            } else {
3030                break;
3031            }
3032        }
3033
3034        did_expand_hunks || !old_expanded_hunks.is_empty()
3035    }
3036
3037    fn append_diff_transforms(
3038        new_transforms: &mut SumTree<DiffTransform>,
3039        subtree: SumTree<DiffTransform>,
3040    ) {
3041        if let Some(DiffTransform::BufferContent {
3042            inserted_hunk_info,
3043            summary,
3044        }) = subtree.first()
3045            && Self::extend_last_buffer_content_transform(
3046                new_transforms,
3047                *inserted_hunk_info,
3048                *summary,
3049            )
3050        {
3051            let mut cursor = subtree.cursor::<()>(());
3052            cursor.next();
3053            cursor.next();
3054            new_transforms.append(cursor.suffix(), ());
3055            return;
3056        }
3057        new_transforms.append(subtree, ());
3058    }
3059
3060    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3061        if let DiffTransform::BufferContent {
3062            inserted_hunk_info: inserted_hunk_anchor,
3063            summary,
3064        } = transform
3065            && Self::extend_last_buffer_content_transform(
3066                new_transforms,
3067                inserted_hunk_anchor,
3068                summary,
3069            )
3070        {
3071            return;
3072        }
3073        new_transforms.push(transform, ());
3074    }
3075
3076    fn push_buffer_content_transform(
3077        old_snapshot: &MultiBufferSnapshot,
3078        new_transforms: &mut SumTree<DiffTransform>,
3079        end_offset: ExcerptOffset,
3080        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3081    ) {
3082        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3083            (end_offset.min(insertion_end_offset), Some(hunk_info))
3084        });
3085        let unchanged_region = [(end_offset, None)];
3086
3087        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3088        {
3089            let start_offset = new_transforms.summary().excerpt_len();
3090            if end_offset <= start_offset {
3091                continue;
3092            }
3093            let summary_to_add = old_snapshot
3094                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3095
3096            if !Self::extend_last_buffer_content_transform(
3097                new_transforms,
3098                inserted_hunk_info,
3099                summary_to_add,
3100            ) {
3101                new_transforms.push(
3102                    DiffTransform::BufferContent {
3103                        summary: summary_to_add,
3104                        inserted_hunk_info,
3105                    },
3106                    (),
3107                )
3108            }
3109        }
3110    }
3111
3112    fn extend_last_buffer_content_transform(
3113        new_transforms: &mut SumTree<DiffTransform>,
3114        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3115        summary_to_add: MBTextSummary,
3116    ) -> bool {
3117        let mut did_extend = false;
3118        new_transforms.update_last(
3119            |last_transform| {
3120                if let DiffTransform::BufferContent {
3121                    summary,
3122                    inserted_hunk_info: inserted_hunk_anchor,
3123                } = last_transform
3124                    && *inserted_hunk_anchor == new_inserted_hunk_info
3125                {
3126                    *summary += summary_to_add;
3127                    did_extend = true;
3128                }
3129            },
3130            (),
3131        );
3132        did_extend
3133    }
3134
3135    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3136        let snapshot = self.snapshot(cx);
3137        let excerpt_end = snapshot
3138            .excerpt_containing(range.end..range.end)
3139            .map(|excerpt| excerpt.end_anchor().into())
3140            .unwrap_or(Anchor::Max);
3141        let point_range = range.to_point(&snapshot);
3142        let expand = !self.single_hunk_is_expanded(range, cx);
3143        let edits =
3144            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_end)], expand, cx);
3145        if !edits.is_empty() {
3146            self.subscriptions.publish(edits);
3147        }
3148        cx.emit(Event::DiffHunksToggled);
3149        cx.emit(Event::Edited {
3150            edited_buffer: None,
3151        });
3152    }
3153}
3154
3155fn build_excerpt_ranges(
3156    ranges: impl IntoIterator<Item = Range<Point>>,
3157    context_line_count: u32,
3158    buffer_snapshot: &BufferSnapshot,
3159) -> Vec<ExcerptRange<Point>> {
3160    ranges
3161        .into_iter()
3162        .map(|range| {
3163            let start_row = range.start.row.saturating_sub(context_line_count);
3164            let start = Point::new(start_row, 0);
3165            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3166            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3167            ExcerptRange {
3168                context: start..end,
3169                primary: range,
3170            }
3171        })
3172        .collect()
3173}
3174
3175#[cfg(any(test, feature = "test-support"))]
3176impl MultiBuffer {
3177    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3178        let buffer = cx.new(|cx| Buffer::local(text, cx));
3179        cx.new(|cx| Self::singleton(buffer, cx))
3180    }
3181
3182    pub fn build_multi<const COUNT: usize>(
3183        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3184        cx: &mut gpui::App,
3185    ) -> Entity<Self> {
3186        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3187        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3188            let buffer = cx.new(|cx| Buffer::local(text, cx));
3189            let snapshot = buffer.read(cx).snapshot();
3190            let excerpt_ranges = ranges
3191                .into_iter()
3192                .map(ExcerptRange::new)
3193                .collect::<Vec<_>>();
3194            multi.update(cx, |multi, cx| {
3195                multi.set_excerpt_ranges_for_path(
3196                    PathKey::sorted(ix as u64),
3197                    buffer,
3198                    &snapshot,
3199                    excerpt_ranges,
3200                    cx,
3201                )
3202            });
3203        }
3204
3205        multi
3206    }
3207
3208    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3209        cx.new(|cx| Self::singleton(buffer, cx))
3210    }
3211
3212    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3213        cx.new(|cx| {
3214            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3215            let mutation_count = rng.random_range(1..=5);
3216            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3217            multibuffer
3218        })
3219    }
3220
3221    pub fn randomly_edit(
3222        &mut self,
3223        rng: &mut impl rand::Rng,
3224        edit_count: usize,
3225        cx: &mut Context<Self>,
3226    ) {
3227        use util::RandomCharIter;
3228
3229        let snapshot = self.read(cx);
3230        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3231        let mut last_end = None;
3232        for _ in 0..edit_count {
3233            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3234                break;
3235            }
3236
3237            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3238            let end =
3239                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3240            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3241            last_end = Some(end);
3242
3243            let mut range = start..end;
3244            if rng.random_bool(0.2) {
3245                mem::swap(&mut range.start, &mut range.end);
3246            }
3247
3248            let new_text_len = rng.random_range(0..10);
3249            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3250
3251            edits.push((range, new_text.into()));
3252        }
3253        log::info!("mutating multi-buffer with {:?}", edits);
3254        drop(snapshot);
3255
3256        self.edit(edits, None, cx);
3257    }
3258
3259    pub fn randomly_edit_excerpts(
3260        &mut self,
3261        rng: &mut impl rand::Rng,
3262        mutation_count: usize,
3263        cx: &mut Context<Self>,
3264    ) {
3265        use rand::prelude::*;
3266        use std::env;
3267        use util::RandomCharIter;
3268
3269        let max_buffers = env::var("MAX_BUFFERS")
3270            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3271            .unwrap_or(5);
3272
3273        let mut buffers = Vec::new();
3274        for _ in 0..mutation_count {
3275            let buffer_ids = self.all_buffer_ids();
3276            if buffer_ids.is_empty() || (rng.random() && buffer_ids.len() < max_buffers) {
3277                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3278                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3279                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3280                    let buffer = buffers.last().unwrap().read(cx);
3281                    log::info!(
3282                        "Creating new buffer {} with text: {:?}",
3283                        buffer.remote_id(),
3284                        buffer.text()
3285                    );
3286                    buffers.last().unwrap().clone()
3287                } else {
3288                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3289                };
3290
3291                let buffer = buffer_handle.read(cx);
3292                let buffer_text = buffer.text();
3293                let buffer_snapshot = buffer.snapshot();
3294                let mut next_min_start_ix = 0;
3295                let ranges = (0..rng.random_range(0..5))
3296                    .filter_map(|_| {
3297                        if next_min_start_ix == buffer.len() {
3298                            return None;
3299                        }
3300                        let end_ix = buffer.clip_offset(
3301                            rng.random_range(next_min_start_ix..=buffer.len()),
3302                            Bias::Right,
3303                        );
3304                        let start_ix = buffer
3305                            .clip_offset(rng.random_range(next_min_start_ix..=end_ix), Bias::Left);
3306                        next_min_start_ix = end_ix;
3307                        Some(ExcerptRange::new(start_ix..end_ix))
3308                    })
3309                    .collect::<Vec<_>>();
3310                log::info!(
3311                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3312                    buffer_handle.read(cx).remote_id(),
3313                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3314                    ranges
3315                        .iter()
3316                        .map(|r| &buffer_text[r.context.clone()])
3317                        .collect::<Vec<_>>()
3318                );
3319
3320                let path_key = PathKey::sorted(rng.random_range(0..max_buffers * 3) as u64);
3321                self.set_merged_excerpt_ranges_for_path(
3322                    path_key.clone(),
3323                    buffer_handle,
3324                    &buffer_snapshot,
3325                    ranges,
3326                    cx,
3327                );
3328                log::info!("Inserted with path_key: {:?}", path_key);
3329            } else {
3330                let path_key = self
3331                    .snapshot
3332                    .borrow()
3333                    .buffers
3334                    .get(&buffer_ids.choose(rng).unwrap())
3335                    .unwrap()
3336                    .path_key
3337                    .clone();
3338                log::info!("Removing excerpts {:?}", path_key);
3339                self.remove_excerpts_for_path(path_key, cx);
3340            }
3341        }
3342    }
3343
3344    pub fn randomly_mutate(
3345        &mut self,
3346        rng: &mut impl rand::Rng,
3347        mutation_count: usize,
3348        cx: &mut Context<Self>,
3349    ) {
3350        use rand::prelude::*;
3351
3352        if rng.random_bool(0.7) || self.singleton {
3353            let buffer = self
3354                .buffers
3355                .values()
3356                .choose(rng)
3357                .map(|state| state.buffer.clone());
3358
3359            if let Some(buffer) = buffer {
3360                buffer.update(cx, |buffer, cx| {
3361                    if rng.random() {
3362                        buffer.randomly_edit(rng, mutation_count, cx);
3363                    } else {
3364                        buffer.randomly_undo_redo(rng, cx);
3365                    }
3366                });
3367            } else {
3368                self.randomly_edit(rng, mutation_count, cx);
3369            }
3370        } else {
3371            self.randomly_edit_excerpts(rng, mutation_count, cx);
3372        }
3373
3374        self.check_invariants(cx);
3375    }
3376
3377    fn check_invariants(&self, cx: &App) {
3378        self.read(cx).check_invariants();
3379    }
3380}
3381
3382impl EventEmitter<Event> for MultiBuffer {}
3383
3384impl MultiBufferSnapshot {
3385    pub fn text(&self) -> String {
3386        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3387            .map(|chunk| chunk.text)
3388            .collect()
3389    }
3390
3391    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3392        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3393            .flat_map(|c| c.chars().rev())
3394    }
3395
3396    fn reversed_chunks_in_range(
3397        &self,
3398        range: Range<MultiBufferOffset>,
3399    ) -> ReversedMultiBufferChunks<'_> {
3400        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3401        cursor.seek(&range.end);
3402        let current_chunks = cursor.region().as_ref().map(|region| {
3403            let start_overshoot = range.start.saturating_sub(region.range.start);
3404            let end_overshoot = range.end - region.range.start;
3405            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3406            let start = region.buffer_range.start + start_overshoot;
3407            region.buffer.reversed_chunks_in_range(start..end)
3408        });
3409        ReversedMultiBufferChunks {
3410            cursor,
3411            current_chunks,
3412            start: range.start,
3413            offset: range.end,
3414        }
3415    }
3416
3417    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3418        let offset = position.to_offset(self);
3419        self.text_for_range(offset..self.len())
3420            .flat_map(|chunk| chunk.chars())
3421    }
3422
3423    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3424        self.chunks(range, false).map(|chunk| chunk.text)
3425    }
3426
3427    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3428        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3429            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3430    }
3431
3432    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3433    where
3434        T: ToOffset,
3435    {
3436        let position = position.to_offset(self);
3437        position == self.clip_offset(position, Bias::Left)
3438            && self
3439                .bytes_in_range(position..self.len())
3440                .flatten()
3441                .copied()
3442                .take(needle.len())
3443                .eq(needle.bytes())
3444    }
3445
3446    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3447        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3448    }
3449
3450    pub fn diff_hunks_in_range<T: ToPoint>(
3451        &self,
3452        range: Range<T>,
3453    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3454        let query_range = range.start.to_point(self)..range.end.to_point(self);
3455        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3456            let diff = self.diffs.get(&buffer.remote_id())?;
3457            let iter = if let Some(main_buffer) = &diff.main_buffer {
3458                let buffer_start = buffer.point_to_offset(buffer_range.start);
3459                let buffer_end = buffer.point_to_offset(buffer_range.end);
3460                itertools::Either::Left(
3461                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3462                        .map(move |hunk| (hunk, buffer, true)),
3463                )
3464            } else {
3465                let buffer_start = buffer.anchor_before(buffer_range.start);
3466                let buffer_end = buffer.anchor_after(buffer_range.end);
3467                itertools::Either::Right(
3468                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3469                        .map(move |hunk| (hunk, buffer, false)),
3470                )
3471            };
3472            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3473                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3474                    return None;
3475                }
3476                let range = if is_inverted {
3477                    hunk.diff_base_byte_range.to_point(&buffer)
3478                } else {
3479                    hunk.range.clone()
3480                };
3481                Some((range, (hunk, is_inverted)))
3482            }))
3483        })
3484        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3485            let buffer_snapshot = excerpt.buffer_snapshot(self);
3486            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3487            {
3488                return None;
3489            }
3490            let end_row = if range.end.column == 0 {
3491                range.end.row
3492            } else {
3493                range.end.row + 1
3494            };
3495
3496            let word_diffs =
3497                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3498                    .then(|| {
3499                        let mut word_diffs = Vec::new();
3500
3501                        if self.show_deleted_hunks || is_inverted {
3502                            let hunk_start_offset = if is_inverted {
3503                                Anchor::in_buffer(
3504                                    excerpt.path_key_index,
3505                                    buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start),
3506                                )
3507                                .to_offset(self)
3508                            } else {
3509                                Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3510                                    .to_offset(self)
3511                            };
3512
3513                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3514                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3515                            }));
3516                        }
3517
3518                        if !is_inverted {
3519                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3520                                Anchor::range_in_buffer(excerpt.path_key_index, diff)
3521                                    .to_offset(self)
3522                            }));
3523                        }
3524                        word_diffs
3525                    })
3526                    .unwrap_or_default();
3527
3528            let buffer_range = if is_inverted {
3529                buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start)
3530                    ..buffer_snapshot.anchor_before(hunk.diff_base_byte_range.end)
3531            } else {
3532                hunk.buffer_range.clone()
3533            };
3534            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3535                DiffHunkStatusKind::Deleted
3536            } else if hunk.diff_base_byte_range.is_empty() {
3537                DiffHunkStatusKind::Added
3538            } else {
3539                DiffHunkStatusKind::Modified
3540            };
3541            Some(MultiBufferDiffHunk {
3542                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3543                buffer_id: buffer_snapshot.remote_id(),
3544                path_key_index: excerpt.path_key_index,
3545                buffer_range,
3546                word_diffs,
3547                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3548                    ..BufferOffset(hunk.diff_base_byte_range.end),
3549                status: DiffHunkStatus {
3550                    kind: status_kind,
3551                    secondary: hunk.secondary_status,
3552                },
3553            })
3554        })
3555    }
3556
3557    fn excerpts_for_range<T: ToOffset>(
3558        &self,
3559        range: Range<T>,
3560    ) -> impl Iterator<Item = &Excerpt> + '_ {
3561        let range = range.start.to_offset(self)..range.end.to_offset(self);
3562        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3563        cursor.seek(&range.start);
3564        std::iter::from_fn(move || {
3565            let region = cursor.region()?;
3566            if region.range.start > range.end
3567                || region.range.start == range.end && region.range.start > range.start
3568            {
3569                return None;
3570            }
3571            let excerpt = region.excerpt;
3572            cursor.next_excerpt_forwards();
3573            Some(excerpt)
3574        })
3575    }
3576
3577    // todo!() repeats ids? seems weird
3578    pub fn buffer_ids_for_range<T: ToOffset>(
3579        &self,
3580        range: Range<T>,
3581    ) -> impl Iterator<Item = BufferId> + '_ {
3582        self.excerpts_for_range(range)
3583            .map(|excerpt| excerpt.buffer_snapshot(self).remote_id())
3584    }
3585
3586    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3587    ///
3588    /// The passed in anchors must be ordered.
3589    pub fn text_anchors_to_visible_anchors(
3590        &self,
3591        anchors: impl IntoIterator<Item = text::Anchor>,
3592    ) -> Vec<Option<Anchor>> {
3593        let anchors = anchors.into_iter();
3594        let mut result = Vec::with_capacity(anchors.size_hint().0);
3595        let mut anchors = anchors.peekable();
3596        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3597        'anchors: while let Some(anchor) = anchors.peek() {
3598            let buffer_id = anchor.buffer_id;
3599            let mut same_buffer_anchors = anchors.peeking_take_while(|a| a.buffer_id == buffer_id);
3600
3601            if let Some(buffer) = self.buffers.get(&buffer_id) {
3602                let path = &buffer.path_key;
3603                let Some(mut next) = same_buffer_anchors.next() else {
3604                    continue 'anchors;
3605                };
3606                cursor.seek_forward(path, Bias::Left);
3607                'excerpts: loop {
3608                    let Some(excerpt) = cursor.item() else {
3609                        break;
3610                    };
3611                    if &excerpt.path_key != path {
3612                        break;
3613                    }
3614                    let buffer_snapshot = excerpt.buffer_snapshot(self);
3615
3616                    loop {
3617                        // anchor is before the first excerpt
3618                        if excerpt
3619                            .range
3620                            .context
3621                            .start
3622                            .cmp(&next, &buffer_snapshot)
3623                            .is_gt()
3624                        {
3625                            // so we skip it and try the next anchor
3626                            result.push(None);
3627                            match same_buffer_anchors.next() {
3628                                Some(anchor) => next = anchor,
3629                                None => continue 'anchors,
3630                            }
3631                        // anchor is within the excerpt
3632                        } else if excerpt
3633                            .range
3634                            .context
3635                            .end
3636                            .cmp(&next, &buffer_snapshot)
3637                            .is_ge()
3638                        {
3639                            // record it and all following anchors that are within
3640                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3641                            result.extend(
3642                                same_buffer_anchors
3643                                    .peeking_take_while(|a| {
3644                                        excerpt.range.context.end.cmp(a, &buffer_snapshot).is_ge()
3645                                    })
3646                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3647                            );
3648                            match same_buffer_anchors.next() {
3649                                Some(anchor) => next = anchor,
3650                                None => continue 'anchors,
3651                            }
3652                        // anchor is after the excerpt, try the next one
3653                        } else {
3654                            cursor.next();
3655                            continue 'excerpts;
3656                        }
3657                    }
3658                }
3659                // account for `next`
3660                result.push(None);
3661            }
3662            result.extend(same_buffer_anchors.map(|_| None));
3663        }
3664
3665        result
3666    }
3667
3668    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3669        &self,
3670        ranges: impl Iterator<Item = Range<T>>,
3671    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>)> {
3672        ranges.flat_map(|range| {
3673            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3674                .into_iter()
3675        })
3676    }
3677
3678    // todo!() can we make this not RangeBounds
3679    pub fn range_to_buffer_ranges<R, T>(
3680        &self,
3681        range: R,
3682    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>)>
3683    where
3684        R: RangeBounds<T>,
3685        T: ToOffset,
3686    {
3687        self.range_to_buffer_ranges_with_context(range)
3688            .into_iter()
3689            .map(|(buffer, range, _context)| (buffer, range))
3690            .collect()
3691    }
3692
3693    pub fn range_to_buffer_ranges_with_context<R, T>(
3694        &self,
3695        range: R,
3696    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)>
3697    where
3698        R: RangeBounds<T>,
3699        T: ToOffset,
3700    {
3701        let start = match range.start_bound() {
3702            Bound::Included(start) => start.to_offset(self),
3703            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3704            Bound::Unbounded => MultiBufferOffset::ZERO,
3705        };
3706        let end_bound = match range.end_bound() {
3707            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3708            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3709            Bound::Unbounded => Bound::Unbounded,
3710        };
3711        let bounds = (Bound::Included(start), end_bound);
3712
3713        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3714        cursor.seek(&start);
3715
3716        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)> =
3717            Vec::new();
3718        let mut last_excerpt = None;
3719        while let Some(region) = cursor.region() {
3720            let dominated_by_end_bound = match end_bound {
3721                Bound::Included(end) => region.range.start > end,
3722                Bound::Excluded(end) => region.range.start >= end,
3723                Bound::Unbounded => false,
3724            };
3725            if dominated_by_end_bound {
3726                break;
3727            }
3728            if region.is_main_buffer {
3729                let start_overshoot = start.saturating_sub(region.range.start);
3730                let end_offset = match end_bound {
3731                    Bound::Included(end) | Bound::Excluded(end) => end,
3732                    Bound::Unbounded => region.range.end,
3733                };
3734                let end_overshoot = end_offset.saturating_sub(region.range.start);
3735                let start = region
3736                    .buffer_range
3737                    .end
3738                    .min(region.buffer_range.start + start_overshoot);
3739                let end = region
3740                    .buffer_range
3741                    .end
3742                    .min(region.buffer_range.start + end_overshoot);
3743                let context = region.excerpt.range.context.clone();
3744                if last_excerpt
3745                    .as_ref()
3746                    .is_some_and(|prev_excerpt| prev_excerpt == &region.excerpt.info())
3747                    && let Some(prev) = result
3748                        .last_mut()
3749                        .filter(|(_, prev_range, _)| prev_range.end == start)
3750                {
3751                    prev.1.end = end;
3752                } else {
3753                    result.push((region.buffer, start..end, context));
3754                    // todo!() is there a better way to do this?
3755                    last_excerpt = Some(region.excerpt.info())
3756                }
3757            }
3758            cursor.next();
3759        }
3760
3761        if let Some(excerpt) = cursor.excerpt() {
3762            let dominated_by_prev_excerpt =
3763                last_excerpt.is_some_and(|last_excerpt| last_excerpt == excerpt.info());
3764            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3765                let excerpt_position = self.len();
3766                let buffer_snapshot = excerpt.buffer_snapshot(self);
3767                if bounds.contains(&excerpt_position) {
3768                    let buffer_offset =
3769                        BufferOffset(excerpt.range.context.start.to_offset(buffer_snapshot));
3770                    let context = excerpt.range.context.clone();
3771                    result.push((buffer_snapshot, buffer_offset..buffer_offset, context));
3772                }
3773            }
3774        }
3775
3776        result
3777    }
3778
3779    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3780        &self,
3781        range: Range<T>,
3782    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, Option<Anchor>)> + '_ {
3783        let start = range.start.to_offset(self);
3784        let end = range.end.to_offset(self);
3785
3786        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3787        cursor.seek(&start);
3788
3789        std::iter::from_fn(move || {
3790            let region = cursor.region()?;
3791            if region.range.start > end {
3792                return None;
3793            }
3794            let start_overshoot = start.saturating_sub(region.range.start);
3795            let end_overshoot = end.saturating_sub(region.range.start);
3796            let start = region
3797                .buffer_range
3798                .end
3799                .min(region.buffer_range.start + start_overshoot);
3800            let end = region
3801                .buffer_range
3802                .end
3803                .min(region.buffer_range.start + end_overshoot);
3804
3805            let deleted_hunk_anchor = if region.is_main_buffer {
3806                None
3807            } else {
3808                Some(self.anchor_before(region.range.start))
3809            };
3810            let result = (region.buffer, start..end, deleted_hunk_anchor);
3811            cursor.next();
3812            Some(result)
3813        })
3814    }
3815
3816    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3817    /// coordinates.
3818    ///
3819    /// The given callback will be called for every excerpt intersecting the given range. It will
3820    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3821    /// The callback should return an iterator of metadata items from that buffer, each paired
3822    /// with a buffer range.
3823    ///
3824    /// The returned iterator yields each of these metadata items, paired with its range in
3825    /// multi-buffer coordinates.
3826    fn lift_buffer_metadata<'a, MBD, M, I>(
3827        &'a self,
3828        query_range: Range<MBD>,
3829        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3830    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3831    where
3832        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3833        MBD: MultiBufferDimension
3834            + Ord
3835            + Sub<Output = MBD::TextDimension>
3836            + ops::Add<MBD::TextDimension, Output = MBD>
3837            + ops::AddAssign<MBD::TextDimension>,
3838        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3839            + ops::Add<Output = MBD::TextDimension>
3840            + AddAssign<MBD::TextDimension>
3841            + Ord,
3842    {
3843        let mut current_excerpt_metadata: Option<(ExcerptAnchor, I)> = None;
3844        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3845
3846        // Find the excerpt and buffer offset where the given range ends.
3847        cursor.seek(&query_range.end);
3848        let mut range_end = None;
3849        while let Some(region) = cursor.region() {
3850            if region.is_main_buffer {
3851                let mut buffer_end = region.buffer_range.start;
3852                let overshoot = if query_range.end > region.range.start {
3853                    query_range.end - region.range.start
3854                } else {
3855                    <MBD::TextDimension>::default()
3856                };
3857                buffer_end = buffer_end + overshoot;
3858                range_end = Some((region.excerpt.end_anchor(), buffer_end));
3859                break;
3860            }
3861            cursor.next();
3862        }
3863
3864        cursor.seek(&query_range.start);
3865
3866        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3867            && region.range.start > MBD::default()
3868        {
3869            cursor.prev()
3870        } else if let Some(region) = cursor.region()
3871            && region.is_main_buffer
3872            && region.diff_hunk_status.is_some()
3873        {
3874            cursor.prev();
3875            if cursor.region().is_none_or(|region| region.is_main_buffer) {
3876                cursor.next();
3877            }
3878        }
3879
3880        iter::from_fn(move || {
3881            loop {
3882                let excerpt = cursor.excerpt()?;
3883                let buffer_snapshot = excerpt.buffer_snapshot(self);
3884
3885                // If we have already retrieved metadata for this excerpt, continue to use it.
3886                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3887                    .as_mut()
3888                    .filter(|(excerpt_anchor, _)| excerpt_anchor == &excerpt.end_anchor())
3889                {
3890                    Some(metadata)
3891                }
3892                // Otherwise, compute the intersection of the input range with the excerpt's range,
3893                // and retrieve the metadata for the resulting range.
3894                else {
3895                    let region = cursor.region()?;
3896                    let mut buffer_start;
3897                    if region.is_main_buffer {
3898                        buffer_start = region.buffer_range.start;
3899                        if query_range.start > region.range.start {
3900                            let overshoot = query_range.start - region.range.start;
3901                            buffer_start = buffer_start + overshoot;
3902                        }
3903                        buffer_start = buffer_start.min(region.buffer_range.end);
3904                    } else {
3905                        buffer_start = cursor.main_buffer_position()?;
3906                    };
3907                    let mut buffer_end = excerpt
3908                        .range
3909                        .context
3910                        .end
3911                        .summary::<MBD::TextDimension>(&buffer_snapshot);
3912                    if let Some((end_excerpt, end_buffer_offset)) = range_end
3913                        && excerpt.end_anchor() == end_excerpt
3914                    {
3915                        buffer_end = buffer_end.min(end_buffer_offset);
3916                    }
3917
3918                    get_buffer_metadata(&buffer_snapshot, buffer_start..buffer_end).map(
3919                        |iterator| {
3920                            &mut current_excerpt_metadata
3921                                .insert((excerpt.end_anchor(), iterator))
3922                                .1
3923                        },
3924                    )
3925                };
3926
3927                // Visit each metadata item.
3928                if let Some((metadata_buffer_range, metadata)) =
3929                    metadata_iter.and_then(Iterator::next)
3930                {
3931                    // Find the multibuffer regions that contain the start and end of
3932                    // the metadata item's range.
3933                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3934                        while let Some(region) = cursor.region() {
3935                            if (region.is_main_buffer
3936                                && (region.buffer_range.end >= metadata_buffer_range.start
3937                                    || cursor.is_at_end_of_excerpt()))
3938                                || (!region.is_main_buffer
3939                                    && region.buffer_range.start == metadata_buffer_range.start)
3940                            {
3941                                break;
3942                            }
3943                            cursor.next();
3944                        }
3945                    }
3946                    let start_region = cursor.region()?.clone();
3947                    while let Some(region) = cursor.region() {
3948                        if region.is_main_buffer
3949                            && (region.buffer_range.end > metadata_buffer_range.end
3950                                || cursor.is_at_end_of_excerpt())
3951                        {
3952                            break;
3953                        }
3954                        cursor.next();
3955                    }
3956                    let end_region = cursor.region();
3957
3958                    // Convert the metadata item's range into multibuffer coordinates.
3959                    let mut start_position = start_region.range.start;
3960                    let region_buffer_start = start_region.buffer_range.start;
3961                    if start_region.is_main_buffer
3962                        && metadata_buffer_range.start > region_buffer_start
3963                    {
3964                        start_position =
3965                            start_position + (metadata_buffer_range.start - region_buffer_start);
3966                        start_position = start_position.min(start_region.range.end);
3967                    }
3968
3969                    let mut end_position = self.max_position();
3970                    if let Some(end_region) = &end_region {
3971                        end_position = end_region.range.start;
3972                        debug_assert!(end_region.is_main_buffer);
3973                        let region_buffer_start = end_region.buffer_range.start;
3974                        if metadata_buffer_range.end > region_buffer_start {
3975                            end_position =
3976                                end_position + (metadata_buffer_range.end - region_buffer_start);
3977                        }
3978                        end_position = end_position.min(end_region.range.end);
3979                    }
3980
3981                    if start_position <= query_range.end && end_position >= query_range.start {
3982                        return Some((start_position..end_position, metadata, excerpt));
3983                    }
3984                }
3985                // When there are no more metadata items for this excerpt, move to the next excerpt.
3986                else {
3987                    current_excerpt_metadata.take();
3988                    if let Some((end_excerpt, _)) = range_end
3989                        && excerpt.end_anchor() == end_excerpt
3990                    {
3991                        return None;
3992                    }
3993                    cursor.next_excerpt_forwards();
3994                }
3995            }
3996        })
3997    }
3998
3999    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4000        let offset = position.to_offset(self);
4001
4002        let mut cursor = self
4003            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4004            );
4005        cursor.seek(&DimensionPair {
4006            key: offset,
4007            value: None,
4008        });
4009        cursor.seek_to_start_of_current_excerpt();
4010        let excerpt = cursor.excerpt()?;
4011
4012        let buffer = excerpt.buffer_snapshot(self);
4013        let excerpt_start = excerpt.range.context.start.to_offset(buffer);
4014        let excerpt_end = excerpt.range.context.end.to_offset(buffer);
4015        let current_position = match self.anchor_before(offset) {
4016            Anchor::Min => 0,
4017            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor.text_anchor().to_offset(buffer),
4018            Anchor::Max => unreachable!(),
4019        };
4020
4021        if let Some(diff) = self.diffs.get(&buffer.remote_id()) {
4022            if let Some(main_buffer) = &diff.main_buffer {
4023                for hunk in diff
4024                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4025                {
4026                    if hunk.diff_base_byte_range.end >= current_position {
4027                        continue;
4028                    }
4029                    let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
4030                    let start =
4031                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4032                    return Some(MultiBufferRow(start.row));
4033                }
4034            } else {
4035                let excerpt_end = buffer.anchor_before(excerpt_end.min(current_position));
4036                for hunk in diff
4037                    .hunks_intersecting_range_rev(excerpt.range.context.start..excerpt_end, buffer)
4038                {
4039                    let hunk_end = hunk.buffer_range.end.to_offset(buffer);
4040                    if hunk_end >= current_position {
4041                        continue;
4042                    }
4043                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4044                        .to_point(self);
4045                    return Some(MultiBufferRow(start.row));
4046                }
4047            }
4048        }
4049
4050        loop {
4051            cursor.prev_excerpt();
4052            let excerpt = cursor.excerpt()?;
4053
4054            let buffer = excerpt.buffer_snapshot(self);
4055            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
4056                continue;
4057            };
4058            if let Some(main_buffer) = &diff.main_buffer {
4059                let Some(hunk) = diff
4060                    .hunks_intersecting_base_text_range_rev(
4061                        excerpt.range.context.to_offset(buffer),
4062                        main_buffer,
4063                    )
4064                    .next()
4065                else {
4066                    continue;
4067                };
4068                let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
4069                let start = Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4070                return Some(MultiBufferRow(start.row));
4071            } else {
4072                let Some(hunk) = diff
4073                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), buffer)
4074                    .next()
4075                else {
4076                    continue;
4077                };
4078                let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4079                    .to_point(self);
4080                return Some(MultiBufferRow(start.row));
4081            }
4082        }
4083    }
4084
4085    pub fn has_diff_hunks(&self) -> bool {
4086        self.diffs.values().any(|diff| !diff.is_empty())
4087    }
4088
4089    pub fn is_inside_word<T: ToOffset>(
4090        &self,
4091        position: T,
4092        scope_context: Option<CharScopeContext>,
4093    ) -> bool {
4094        let position = position.to_offset(self);
4095        let classifier = self
4096            .char_classifier_at(position)
4097            .scope_context(scope_context);
4098        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4099        let prev_char_kind = self
4100            .reversed_chars_at(position)
4101            .next()
4102            .map(|c| classifier.kind(c));
4103        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4104    }
4105
4106    pub fn surrounding_word<T: ToOffset>(
4107        &self,
4108        start: T,
4109        scope_context: Option<CharScopeContext>,
4110    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4111        let mut start = start.to_offset(self);
4112        let mut end = start;
4113        let mut next_chars = self.chars_at(start).peekable();
4114        let mut prev_chars = self.reversed_chars_at(start).peekable();
4115
4116        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4117
4118        let word_kind = cmp::max(
4119            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4120            next_chars.peek().copied().map(|c| classifier.kind(c)),
4121        );
4122
4123        for ch in prev_chars {
4124            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4125                start -= ch.len_utf8();
4126            } else {
4127                break;
4128            }
4129        }
4130
4131        for ch in next_chars {
4132            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4133                end += ch.len_utf8();
4134            } else {
4135                break;
4136            }
4137        }
4138
4139        (start..end, word_kind)
4140    }
4141
4142    pub fn char_kind_before<T: ToOffset>(
4143        &self,
4144        start: T,
4145        scope_context: Option<CharScopeContext>,
4146    ) -> Option<CharKind> {
4147        let start = start.to_offset(self);
4148        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4149        self.reversed_chars_at(start)
4150            .next()
4151            .map(|ch| classifier.kind(ch))
4152    }
4153
4154    pub fn is_singleton(&self) -> bool {
4155        self.singleton
4156    }
4157
4158    pub fn as_singleton(&self) -> Option<&BufferSnapshot> {
4159        if self.singleton {
4160            self.excerpts.first().map(|e| e.buffer_snapshot(self))
4161        } else {
4162            None
4163        }
4164    }
4165
4166    pub fn len(&self) -> MultiBufferOffset {
4167        self.diff_transforms.summary().output.len
4168    }
4169
4170    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4171        MBD::from_summary(&self.text_summary())
4172    }
4173
4174    pub fn is_empty(&self) -> bool {
4175        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4176    }
4177
4178    pub fn widest_line_number(&self) -> u32 {
4179        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4180        self.excerpts.summary().widest_line_number + 1
4181    }
4182
4183    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4184        let range = range.start.to_offset(self)..range.end.to_offset(self);
4185        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4186        excerpts.seek(&range.start);
4187
4188        let mut chunk;
4189        let mut has_trailing_newline;
4190        let excerpt_bytes;
4191        if let Some(region) = excerpts.region() {
4192            let mut bytes = region.buffer.bytes_in_range(
4193                region.buffer_range.start + (range.start - region.range.start)
4194                    ..(region.buffer_range.start + (range.end - region.range.start))
4195                        .min(region.buffer_range.end),
4196            );
4197            chunk = bytes.next().unwrap_or(&[][..]);
4198            excerpt_bytes = Some(bytes);
4199            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4200            if chunk.is_empty() && has_trailing_newline {
4201                chunk = b"\n";
4202                has_trailing_newline = false;
4203            }
4204        } else {
4205            chunk = &[][..];
4206            excerpt_bytes = None;
4207            has_trailing_newline = false;
4208        };
4209
4210        MultiBufferBytes {
4211            range,
4212            cursor: excerpts,
4213            excerpt_bytes,
4214            has_trailing_newline,
4215            chunk,
4216        }
4217    }
4218
4219    pub fn reversed_bytes_in_range<T: ToOffset>(
4220        &self,
4221        range: Range<T>,
4222    ) -> ReversedMultiBufferBytes<'_> {
4223        let range = range.start.to_offset(self)..range.end.to_offset(self);
4224        let mut chunks = self.reversed_chunks_in_range(range.clone());
4225        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4226        ReversedMultiBufferBytes {
4227            range,
4228            chunks,
4229            chunk,
4230        }
4231    }
4232
4233    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4234        dbg!(self.diff_transforms.is_empty());
4235        let mut cursor = self.cursor::<Point, Point>();
4236        cursor.seek(&Point::new(start_row.0, 0));
4237        let mut result = MultiBufferRows {
4238            point: Point::new(0, 0),
4239            is_empty: self.excerpts.is_empty(),
4240            is_singleton: self.is_singleton(),
4241            cursor,
4242        };
4243        result.seek(start_row);
4244        result
4245    }
4246
4247    pub fn chunks<T: ToOffset>(
4248        &self,
4249        range: Range<T>,
4250        language_aware: bool,
4251    ) -> MultiBufferChunks<'_> {
4252        let mut chunks = MultiBufferChunks {
4253            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4254                ..ExcerptDimension(MultiBufferOffset::ZERO),
4255            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4256            excerpts: self.excerpts.cursor(()),
4257            diff_transforms: self.diff_transforms.cursor(()),
4258            diff_base_chunks: None,
4259            excerpt_chunks: None,
4260            buffer_chunk: None,
4261            language_aware,
4262            snapshot: self,
4263        };
4264        let range = range.start.to_offset(self)..range.end.to_offset(self);
4265        chunks.seek(range);
4266        chunks
4267    }
4268
4269    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4270        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4271    }
4272
4273    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4274        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4275    }
4276
4277    pub fn clip_offset_utf16(
4278        &self,
4279        offset: MultiBufferOffsetUtf16,
4280        bias: Bias,
4281    ) -> MultiBufferOffsetUtf16 {
4282        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4283    }
4284
4285    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4286        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4287            buffer.clip_point_utf16(Unclipped(point), bias)
4288        })
4289    }
4290
4291    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4292        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4293    }
4294
4295    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4296        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4297    }
4298
4299    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4300        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4301    }
4302
4303    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4304        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4305    }
4306
4307    #[instrument(skip_all)]
4308    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4309        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4310    }
4311
4312    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4313        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4314    }
4315
4316    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4317        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4318    }
4319
4320    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4321        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4322    }
4323
4324    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4325        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4326    }
4327
4328    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4329        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4330    }
4331
4332    fn clip_dimension<MBD, BD>(
4333        &self,
4334        position: MBD,
4335        bias: Bias,
4336        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4337    ) -> MBD
4338    where
4339        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4340        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4341    {
4342        let mut cursor = self.cursor::<MBD, BD>();
4343        cursor.seek(&position);
4344        if let Some(region) = cursor.region() {
4345            if position >= region.range.end {
4346                return region.range.end;
4347            }
4348            let overshoot = position - region.range.start;
4349            let mut buffer_position = region.buffer_range.start;
4350            buffer_position += overshoot;
4351            let clipped_buffer_position =
4352                clip_buffer_position(region.buffer, buffer_position, bias);
4353            let mut position = region.range.start;
4354            position += clipped_buffer_position - region.buffer_range.start;
4355            position
4356        } else {
4357            self.max_position()
4358        }
4359    }
4360
4361    #[instrument(skip_all)]
4362    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4363        &self,
4364        key: MBR1,
4365        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4366    ) -> MBR2
4367    where
4368        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4369        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4370        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4371        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4372    {
4373        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4374        cursor.seek(&DimensionPair { key, value: None });
4375        if let Some(region) = cursor.region() {
4376            if key >= region.range.end.key {
4377                return region.range.end.value.unwrap();
4378            }
4379            let start_key = region.range.start.key;
4380            let start_value = region.range.start.value.unwrap();
4381            let buffer_start_key = region.buffer_range.start.key;
4382            let buffer_start_value = region.buffer_range.start.value.unwrap();
4383            let mut buffer_key = buffer_start_key;
4384            buffer_key += key - start_key;
4385            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4386            let mut result = start_value;
4387            result += buffer_value - buffer_start_value;
4388            result
4389        } else {
4390            self.max_position()
4391        }
4392    }
4393
4394    pub fn point_to_buffer_offset<T: ToOffset>(
4395        &self,
4396        point: T,
4397    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4398        let offset = point.to_offset(self);
4399        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4400        cursor.seek(&offset);
4401        let region = cursor.region()?;
4402        let overshoot = offset - region.range.start;
4403        let buffer_offset = region.buffer_range.start + overshoot;
4404        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4405            && region.has_trailing_newline
4406            && !region.is_main_buffer
4407        {
4408            let main_buffer_position = cursor.main_buffer_position()?;
4409            let buffer_snapshot = cursor.excerpt()?.buffer_snapshot(self);
4410            return Some((buffer_snapshot, main_buffer_position));
4411        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4412            return None;
4413        }
4414        Some((region.buffer, buffer_offset))
4415    }
4416
4417    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4418        let mut cursor = self.cursor::<Point, Point>();
4419        cursor.seek(&point);
4420        let region = cursor.region()?;
4421        let overshoot = point - region.range.start;
4422        let buffer_point = region.buffer_range.start + overshoot;
4423        let excerpt = cursor.excerpt()?;
4424        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4425            && region.has_trailing_newline
4426            && !region.is_main_buffer
4427        {
4428            return Some((
4429                &excerpt.buffer_snapshot(self),
4430                cursor.main_buffer_position()?,
4431            ));
4432        } else if buffer_point > region.buffer.max_point() {
4433            return None;
4434        }
4435        Some((region.buffer, buffer_point))
4436    }
4437
4438    pub fn suggested_indents(
4439        &self,
4440        rows: impl IntoIterator<Item = u32>,
4441        cx: &App,
4442    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4443        let mut result = BTreeMap::new();
4444        self.suggested_indents_callback(
4445            rows,
4446            &mut |row, indent| {
4447                result.insert(row, indent);
4448                ControlFlow::Continue(())
4449            },
4450            cx,
4451        );
4452        result
4453    }
4454
4455    // move this to be a generator once those are a thing
4456    pub fn suggested_indents_callback(
4457        &self,
4458        rows: impl IntoIterator<Item = u32>,
4459        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4460        cx: &App,
4461    ) {
4462        let mut rows_for_excerpt = Vec::new();
4463        let mut cursor = self.cursor::<Point, Point>();
4464        let mut rows = rows.into_iter().peekable();
4465        let mut prev_row = u32::MAX;
4466        let mut prev_language_indent_size = IndentSize::default();
4467
4468        while let Some(row) = rows.next() {
4469            cursor.seek(&Point::new(row, 0));
4470            let Some(region) = cursor.region() else {
4471                continue;
4472            };
4473
4474            // Retrieve the language and indent size once for each disjoint region being indented.
4475            let single_indent_size = if row.saturating_sub(1) == prev_row {
4476                prev_language_indent_size
4477            } else {
4478                region
4479                    .buffer
4480                    .language_indent_size_at(Point::new(row, 0), cx)
4481            };
4482            prev_language_indent_size = single_indent_size;
4483            prev_row = row;
4484
4485            let start_buffer_row = region.buffer_range.start.row;
4486            let start_multibuffer_row = region.range.start.row;
4487            let end_multibuffer_row = region.range.end.row;
4488
4489            rows_for_excerpt.push(row);
4490            while let Some(next_row) = rows.peek().copied() {
4491                if end_multibuffer_row > next_row {
4492                    rows_for_excerpt.push(next_row);
4493                    rows.next();
4494                } else {
4495                    break;
4496                }
4497            }
4498
4499            let buffer_rows = rows_for_excerpt
4500                .drain(..)
4501                .map(|row| start_buffer_row + row - start_multibuffer_row);
4502            let buffer_indents = region
4503                .buffer
4504                .suggested_indents(buffer_rows, single_indent_size);
4505            for (row, indent) in buffer_indents {
4506                if cb(
4507                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4508                    indent,
4509                )
4510                .is_break()
4511                {
4512                    return;
4513                }
4514            }
4515        }
4516    }
4517
4518    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4519        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4520            let mut size = buffer.indent_size_for_line(range.start.row);
4521            size.len = size
4522                .len
4523                .min(range.end.column)
4524                .saturating_sub(range.start.column);
4525            size
4526        } else {
4527            IndentSize::spaces(0)
4528        }
4529    }
4530
4531    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4532        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4533            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4534        } else {
4535            LineIndent::spaces(0)
4536        }
4537    }
4538
4539    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4540        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4541
4542        if self.language_settings(cx).extend_comment_on_newline
4543            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4544        {
4545            let delimiters = language_scope.line_comment_prefixes();
4546            for delimiter in delimiters {
4547                if *self
4548                    .chars_at(Point::new(row.0, indent.len() as u32))
4549                    .take(delimiter.chars().count())
4550                    .collect::<String>()
4551                    .as_str()
4552                    == **delimiter
4553                {
4554                    indent.push_str(delimiter);
4555                    break;
4556                }
4557            }
4558        }
4559
4560        indent
4561    }
4562
4563    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4564    where
4565        T: ToOffset,
4566    {
4567        for char in self.reversed_chars_at(position) {
4568            if !char.is_whitespace() {
4569                return false;
4570            }
4571            if char == '\n' {
4572                return true;
4573            }
4574        }
4575        true
4576    }
4577
4578    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4579        while row.0 > 0 {
4580            row.0 -= 1;
4581            if !self.is_line_blank(row) {
4582                return Some(row);
4583            }
4584        }
4585        None
4586    }
4587
4588    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4589        if let Some((_, range)) = self.buffer_line_for_row(row) {
4590            range.end.column - range.start.column
4591        } else {
4592            0
4593        }
4594    }
4595
4596    pub fn buffer_line_for_row(
4597        &self,
4598        row: MultiBufferRow,
4599    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4600        let mut cursor = self.cursor::<Point, Point>();
4601        let point = Point::new(row.0, 0);
4602        cursor.seek(&point);
4603        let region = cursor.region()?;
4604        let overshoot = point.min(region.range.end) - region.range.start;
4605        let buffer_point = region.buffer_range.start + overshoot;
4606        if buffer_point.row > region.buffer_range.end.row {
4607            return None;
4608        }
4609        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4610        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4611            .min(region.buffer_range.end);
4612        Some((region.buffer, line_start..line_end))
4613    }
4614
4615    pub fn max_point(&self) -> Point {
4616        self.text_summary().lines
4617    }
4618
4619    pub fn max_row(&self) -> MultiBufferRow {
4620        MultiBufferRow(self.text_summary().lines.row)
4621    }
4622
4623    pub fn text_summary(&self) -> MBTextSummary {
4624        self.diff_transforms.summary().output
4625    }
4626
4627    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4628    where
4629        MBD: MultiBufferDimension + AddAssign,
4630        O: ToOffset,
4631    {
4632        let range = range.start.to_offset(self)..range.end.to_offset(self);
4633        let mut cursor = self
4634            .diff_transforms
4635            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4636        cursor.seek(&range.start, Bias::Right);
4637
4638        let Some(first_transform) = cursor.item() else {
4639            return MBD::from_summary(&MBTextSummary::default());
4640        };
4641
4642        let diff_transform_start = cursor.start().0;
4643        let diff_transform_end = cursor.end().0;
4644        let diff_start = range.start;
4645        let start_overshoot = diff_start - diff_transform_start;
4646        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4647
4648        let mut result = match first_transform {
4649            DiffTransform::BufferContent { .. } => {
4650                let excerpt_start = cursor.start().1 + start_overshoot;
4651                let excerpt_end = cursor.start().1 + end_overshoot;
4652                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4653            }
4654            DiffTransform::DeletedHunk {
4655                buffer_id,
4656                base_text_byte_range,
4657                has_trailing_newline,
4658                ..
4659            } => {
4660                let buffer_start = base_text_byte_range.start + start_overshoot;
4661                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4662                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4663                    panic!("{:?} is in non-existent deleted hunk", range.start)
4664                };
4665
4666                let include_trailing_newline =
4667                    *has_trailing_newline && range.end >= diff_transform_end;
4668                if include_trailing_newline {
4669                    buffer_end -= 1;
4670                }
4671
4672                let mut summary = base_text
4673                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4674
4675                if include_trailing_newline {
4676                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4677                        &TextSummary::newline(),
4678                    ))
4679                }
4680
4681                let mut result = MBD::default();
4682                result.add_text_dim(&summary);
4683                result
4684            }
4685        };
4686        if range.end < diff_transform_end {
4687            return result;
4688        }
4689
4690        cursor.next();
4691        result.add_mb_text_summary(
4692            &cursor
4693                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4694                .0,
4695        );
4696
4697        let Some(last_transform) = cursor.item() else {
4698            return result;
4699        };
4700
4701        let overshoot = range.end - cursor.start().0;
4702        let suffix = match last_transform {
4703            DiffTransform::BufferContent { .. } => {
4704                let end = cursor.start().1 + overshoot;
4705                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4706            }
4707            DiffTransform::DeletedHunk {
4708                base_text_byte_range,
4709                buffer_id,
4710                has_trailing_newline,
4711                ..
4712            } => {
4713                let buffer_end = base_text_byte_range.start + overshoot;
4714                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4715                    panic!("{:?} is in non-existent deleted hunk", range.end)
4716                };
4717
4718                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4719                    base_text_byte_range.start..buffer_end,
4720                );
4721                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4722                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4723                        &TextSummary::from("\n"),
4724                    ))
4725                }
4726
4727                let mut result = MBD::default();
4728                result.add_text_dim(&suffix);
4729                result
4730            }
4731        };
4732
4733        result += suffix;
4734        result
4735    }
4736
4737    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4738    where
4739        MBD: MultiBufferDimension + AddAssign,
4740    {
4741        let mut summary = MBD::default();
4742        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4743        cursor.seek(&range.start, Bias::Right);
4744        if let Some(excerpt) = cursor.item() {
4745            let buffer_snapshot = excerpt.buffer_snapshot(self);
4746            let mut end_before_newline = cursor.end();
4747            if excerpt.has_trailing_newline {
4748                end_before_newline -= 1;
4749            }
4750
4751            let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4752            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4753            let end_in_excerpt =
4754                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4755            summary.add_text_dim(
4756                &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4757                    start_in_excerpt..end_in_excerpt,
4758                ),
4759            );
4760
4761            if range.end > end_before_newline {
4762                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4763            }
4764
4765            cursor.next();
4766        }
4767
4768        if range.end > *cursor.start() {
4769            summary += cursor
4770                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4771                .0;
4772            if let Some(excerpt) = cursor.item() {
4773                let buffer_snapshot = excerpt.buffer_snapshot(self);
4774                range.end = cmp::max(*cursor.start(), range.end);
4775
4776                let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4777                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4778                summary.add_text_dim(
4779                    &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4780                        excerpt_start..end_in_excerpt,
4781                    ),
4782                );
4783            }
4784        }
4785
4786        summary
4787    }
4788
4789    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4790    where
4791        MBD: MultiBufferDimension
4792            + Ord
4793            + Sub<Output = MBD::TextDimension>
4794            + Sub<MBD::TextDimension, Output = MBD>
4795            + AddAssign<MBD::TextDimension>
4796            + Add<MBD::TextDimension, Output = MBD>,
4797        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4798    {
4799        let target = anchor.seek_target(self);
4800        let anchor = match anchor {
4801            Anchor::Min => {
4802                return MBD::default();
4803            }
4804            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4805            Anchor::Max => {
4806                return MBD::from_summary(&self.text_summary());
4807            }
4808        };
4809
4810        let (start, _, item) = self
4811            .excerpts
4812            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4813        let start = MBD::from_summary(&start.text);
4814
4815        let excerpt_start_position = ExcerptDimension(start);
4816        if self.diff_transforms.is_empty() {
4817            if let Some(excerpt) = item {
4818                if !excerpt.contains(anchor, self) {
4819                    return excerpt_start_position.0;
4820                }
4821                let buffer_snapshot = excerpt.buffer_snapshot(self);
4822                let excerpt_buffer_start = excerpt
4823                    .range
4824                    .context
4825                    .start
4826                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4827                let excerpt_buffer_end = excerpt
4828                    .range
4829                    .context
4830                    .end
4831                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4832                let buffer_summary = anchor
4833                    .text_anchor()
4834                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4835                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4836                let mut position = excerpt_start_position;
4837                if summary > excerpt_buffer_start {
4838                    position += summary - excerpt_buffer_start;
4839                }
4840
4841                position.0
4842            } else {
4843                excerpt_start_position.0
4844            }
4845        } else {
4846            let mut diff_transforms_cursor = self
4847                .diff_transforms
4848                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4849            diff_transforms_cursor.next();
4850
4851            if let Some(excerpt) = item {
4852                if !excerpt.contains(anchor, self) {
4853                    return self.summary_for_excerpt_position_without_hunks(
4854                        Bias::Left,
4855                        excerpt_start_position,
4856                        &mut diff_transforms_cursor,
4857                    );
4858                }
4859                let buffer_snapshot = excerpt.buffer_snapshot(self);
4860                let excerpt_buffer_start = excerpt
4861                    .range
4862                    .context
4863                    .start
4864                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4865                let excerpt_buffer_end = excerpt
4866                    .range
4867                    .context
4868                    .end
4869                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4870                let buffer_summary = anchor
4871                    .text_anchor()
4872                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4873                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4874                let mut position = excerpt_start_position;
4875                if summary > excerpt_buffer_start {
4876                    position += summary - excerpt_buffer_start;
4877                }
4878
4879                if diff_transforms_cursor.start().0 < position {
4880                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
4881                }
4882                self.summary_for_anchor_with_excerpt_position(
4883                    *anchor,
4884                    position,
4885                    &mut diff_transforms_cursor,
4886                    &buffer_snapshot,
4887                )
4888            } else {
4889                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
4890                self.summary_for_excerpt_position_without_hunks(
4891                    Bias::Right,
4892                    excerpt_start_position,
4893                    &mut diff_transforms_cursor,
4894                )
4895            }
4896        }
4897    }
4898
4899    /// Maps an anchor's excerpt-space position to its output-space position by
4900    /// walking the diff transforms. The cursor is shared across consecutive
4901    /// calls, so it may already be partway through the transform list.
4902    fn summary_for_anchor_with_excerpt_position<MBD>(
4903        &self,
4904        anchor: ExcerptAnchor,
4905        excerpt_position: ExcerptDimension<MBD>,
4906        diff_transforms: &mut Cursor<
4907            DiffTransform,
4908            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4909        >,
4910        excerpt_buffer: &text::BufferSnapshot,
4911    ) -> MBD
4912    where
4913        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4914    {
4915        loop {
4916            let transform_end_position = diff_transforms.end().0;
4917            let item = diff_transforms.item();
4918            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4919
4920            // A right-biased anchor at a transform boundary belongs to the
4921            // *next* transform, so advance past the current one.
4922            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
4923                diff_transforms.next();
4924                continue;
4925            }
4926
4927            let mut position = diff_transforms.start().1;
4928            match item {
4929                Some(DiffTransform::DeletedHunk {
4930                    buffer_id,
4931                    base_text_byte_range,
4932                    hunk_info,
4933                    ..
4934                }) => {
4935                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
4936                        && let Some(base_text) =
4937                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4938                        && diff_base_anchor.is_valid(&base_text)
4939                    {
4940                        // The anchor carries a diff-base position — resolve it
4941                        // to a location inside the deleted hunk.
4942                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4943                        if base_text_offset >= base_text_byte_range.start
4944                            && base_text_offset <= base_text_byte_range.end
4945                        {
4946                            let position_in_hunk = base_text
4947                                .text_summary_for_range::<MBD::TextDimension, _>(
4948                                    base_text_byte_range.start..base_text_offset,
4949                                );
4950                            position.0.add_text_dim(&position_in_hunk);
4951                        } else if at_transform_end {
4952                            // diff_base offset falls outside this hunk's range;
4953                            // advance to see if the next transform is a better fit.
4954                            diff_transforms.next();
4955                            continue;
4956                        }
4957                    } else if at_transform_end
4958                        && anchor
4959                            .text_anchor()
4960                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
4961                            .is_gt()
4962                    {
4963                        // The anchor has no (valid) diff-base position, so it
4964                        // belongs in the buffer content, not in the deleted
4965                        // hunk. However, after an edit deletes the text between
4966                        // the hunk boundary and this anchor, both resolve to
4967                        // the same excerpt_position—landing us here on the
4968                        // DeletedHunk left behind by the shared cursor. Use the
4969                        // CRDT ordering to detect that the anchor is strictly
4970                        // *past* the hunk boundary and skip to the following
4971                        // BufferContent.
4972                        diff_transforms.next();
4973                        continue;
4974                    }
4975                }
4976                _ => {
4977                    // On a BufferContent (or no transform). If the anchor
4978                    // carries a diff_base_anchor it needs a DeletedHunk, so
4979                    // advance to find one.
4980                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4981                        diff_transforms.next();
4982                        continue;
4983                    }
4984                    let overshoot = excerpt_position - diff_transforms.start().0;
4985                    position += overshoot;
4986                }
4987            }
4988
4989            return position.0;
4990        }
4991    }
4992
4993    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
4994    fn summary_for_excerpt_position_without_hunks<MBD>(
4995        &self,
4996        bias: Bias,
4997        excerpt_position: ExcerptDimension<MBD>,
4998        diff_transforms: &mut Cursor<
4999            DiffTransform,
5000            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5001        >,
5002    ) -> MBD
5003    where
5004        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5005    {
5006        loop {
5007            let transform_end_position = diff_transforms.end().0;
5008            let item = diff_transforms.item();
5009            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5010
5011            // A right-biased anchor at a transform boundary belongs to the
5012            // *next* transform, so advance past the current one.
5013            if bias == Bias::Right && at_transform_end {
5014                diff_transforms.next();
5015                continue;
5016            }
5017
5018            let mut position = diff_transforms.start().1;
5019            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5020                let overshoot = excerpt_position - diff_transforms.start().0;
5021                position += overshoot;
5022            }
5023
5024            return position.0;
5025        }
5026    }
5027
5028    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5029        let anchor = match anchor {
5030            Anchor::Min => return ExcerptOffset::default(),
5031            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5032            Anchor::Max => return self.excerpts.summary().len(),
5033        };
5034        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5035        let target = anchor.seek_target(self);
5036
5037        cursor.seek(&target, Bias::Left);
5038
5039        let mut position = cursor.start().len();
5040        if let Some(excerpt) = cursor.item()
5041            && excerpt.contains(anchor, self)
5042        {
5043            let buffer_snapshot = excerpt.buffer_snapshot(self);
5044            let excerpt_buffer_start =
5045                buffer_snapshot.offset_for_anchor(&excerpt.range.context.start);
5046            let excerpt_buffer_end = buffer_snapshot.offset_for_anchor(&excerpt.range.context.end);
5047            let buffer_position = cmp::min(
5048                excerpt_buffer_end,
5049                buffer_snapshot.offset_for_anchor(&anchor.text_anchor()),
5050            );
5051            if buffer_position > excerpt_buffer_start {
5052                position += buffer_position - excerpt_buffer_start;
5053            }
5054        }
5055        position
5056    }
5057
5058    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5059    where
5060        MBD: MultiBufferDimension
5061            + Ord
5062            + Sub<Output = MBD::TextDimension>
5063            + AddAssign<MBD::TextDimension>,
5064        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5065        I: 'a + IntoIterator<Item = &'a Anchor>,
5066    {
5067        let mut anchors = anchors.into_iter().peekable();
5068        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5069        let mut diff_transforms_cursor = self
5070            .diff_transforms
5071            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5072        diff_transforms_cursor.next();
5073
5074        let mut summaries = Vec::new();
5075        while let Some(anchor) = anchors.peek() {
5076            dbg!(&anchor);
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                            anchors.next();
5125                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5126                        }),
5127                    )
5128                {
5129                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5130                    let mut position = excerpt_start_position;
5131                    if summary > excerpt_buffer_start {
5132                        position += summary - excerpt_buffer_start;
5133                    }
5134
5135                    if diff_transforms_cursor.start().0 < position {
5136                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5137                    }
5138
5139                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5140                        excerpt_anchor,
5141                        position,
5142                        &mut diff_transforms_cursor,
5143                        &buffer_snapshot,
5144                    ));
5145                }
5146            } else {
5147                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5148                let position = self.summary_for_excerpt_position_without_hunks(
5149                    Bias::Right,
5150                    excerpt_start_position,
5151                    &mut diff_transforms_cursor,
5152                );
5153                summaries.push(position);
5154                anchors.next();
5155            }
5156        }
5157
5158        summaries
5159    }
5160
5161    pub fn dimensions_from_points<'a, MBD>(
5162        &'a self,
5163        points: impl 'a + IntoIterator<Item = Point>,
5164    ) -> impl 'a + Iterator<Item = MBD>
5165    where
5166        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5167    {
5168        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5169        cursor.seek(&DimensionPair {
5170            key: Point::default(),
5171            value: None,
5172        });
5173        let mut points = points.into_iter();
5174        iter::from_fn(move || {
5175            let point = points.next()?;
5176
5177            cursor.seek_forward(&DimensionPair {
5178                key: point,
5179                value: None,
5180            });
5181
5182            if let Some(region) = cursor.region() {
5183                let overshoot = point - region.range.start.key;
5184                let buffer_point = region.buffer_range.start + overshoot;
5185                let mut position = region.range.start.value.unwrap();
5186                position.add_text_dim(
5187                    &region
5188                        .buffer
5189                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5190                );
5191                if point == region.range.end.key && region.has_trailing_newline {
5192                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5193                }
5194                Some(position)
5195            } else {
5196                Some(MBD::from_summary(&self.text_summary()))
5197            }
5198        })
5199    }
5200
5201    fn excerpts_for_buffer(&self, buffer_id: BufferId) -> impl Iterator<Item = &Excerpt> {
5202        if let Some(buffer_state) = self.buffers.get(&buffer_id) {
5203            let path_key = buffer_state.path_key.clone();
5204            let mut cursor = self.excerpts.cursor::<PathKey>(());
5205            cursor.seek_forward(&path_key, Bias::Left);
5206            Some(iter::from_fn(move || {
5207                let excerpt = cursor.item()?;
5208                if excerpt.path_key != path_key {
5209                    return None;
5210                }
5211                cursor.next();
5212                Some(excerpt)
5213            }))
5214        } else {
5215            None
5216        }
5217        .into_iter()
5218        .flatten()
5219    }
5220
5221    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5222        self.anchor_at(position, Bias::Left)
5223    }
5224
5225    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5226        self.anchor_at(position, Bias::Right)
5227    }
5228
5229    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5230        let offset = position.to_offset(self);
5231
5232        // Find the given position in the diff transforms. Determine the corresponding
5233        // offset in the excerpts, and whether the position is within a deleted hunk.
5234        let mut diff_transforms = self
5235            .diff_transforms
5236            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5237        diff_transforms.seek(&offset, Bias::Right);
5238
5239        if offset == diff_transforms.start().0
5240            && bias == Bias::Left
5241            && let Some(prev_item) = diff_transforms.prev_item()
5242            && let DiffTransform::DeletedHunk { .. } = prev_item
5243        {
5244            diff_transforms.prev();
5245        }
5246        let offset_in_transform = offset - diff_transforms.start().0;
5247        let mut excerpt_offset = diff_transforms.start().1;
5248        let mut diff_base_anchor = None;
5249        if let Some(DiffTransform::DeletedHunk {
5250            buffer_id,
5251            base_text_byte_range,
5252            has_trailing_newline,
5253            ..
5254        }) = diff_transforms.item()
5255        {
5256            let diff = self.diffs.get(buffer_id).expect("missing diff");
5257            if offset_in_transform > base_text_byte_range.len() {
5258                debug_assert!(*has_trailing_newline);
5259                bias = Bias::Right;
5260            } else {
5261                diff_base_anchor = Some(
5262                    diff.base_text()
5263                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5264                );
5265                bias = Bias::Left;
5266            }
5267        } else {
5268            excerpt_offset += MultiBufferOffset(offset_in_transform);
5269        };
5270
5271        let mut excerpts = self
5272            .excerpts
5273            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5274        excerpts.seek(&excerpt_offset, Bias::Right);
5275        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5276            excerpts.prev();
5277        }
5278        if let Some(excerpt) = excerpts.item() {
5279            let buffer_snapshot = excerpt.buffer_snapshot(self);
5280            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5281            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5282                overshoot -= 1;
5283                bias = Bias::Right;
5284            }
5285
5286            let buffer_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
5287            let text_anchor = excerpt.clip_anchor(
5288                buffer_snapshot.anchor_at(buffer_start + overshoot, bias),
5289                self,
5290            );
5291            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5292            let anchor = match diff_base_anchor {
5293                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5294                None => anchor,
5295            };
5296            anchor.into()
5297        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5298        {
5299            Anchor::min()
5300        } else {
5301            Anchor::max()
5302        }
5303    }
5304
5305    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5306    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5307        let buffer = self.as_singleton()?;
5308        if text_anchor.buffer_id == buffer.remote_id() {
5309            // todo!() bit hacky, but always right for singletons
5310            Some(Anchor::in_buffer(PathKeyIndex(0), text_anchor))
5311        } else {
5312            None
5313        }
5314    }
5315
5316    /// Creates a multibuffer anchor range for the given buffer anchor range, if any excerpt contains both endpoints.
5317    pub fn anchor_range_in_buffer(
5318        &self,
5319        buffer_id: BufferId,
5320        text_anchor: Range<text::Anchor>,
5321    ) -> Option<Range<Anchor>> {
5322        for excerpt in self.excerpts_for_buffer(buffer_id) {
5323            let buffer_snapshot = excerpt.buffer_snapshot(self);
5324            if excerpt.range.contains(&text_anchor.start, &buffer_snapshot)
5325                && excerpt.range.contains(&text_anchor.end, &buffer_snapshot)
5326            {
5327                return Some(Anchor::range_in_buffer(excerpt.path_key_index, text_anchor));
5328            }
5329        }
5330
5331        None
5332    }
5333
5334    /// Creates a multibuffer anchor for the given buffer anchor, if it is contained in any excerpt.
5335    pub fn anchor_in_buffer(
5336        &self,
5337        buffer_id: BufferId,
5338        text_anchor: text::Anchor,
5339    ) -> Option<Anchor> {
5340        for excerpt in self.excerpts_for_buffer(buffer_id) {
5341            let buffer_snapshot = excerpt.buffer_snapshot(self);
5342            if excerpt.range.contains(&text_anchor, &buffer_snapshot) {
5343                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5344            }
5345        }
5346
5347        None
5348    }
5349
5350    pub fn anchors_in_buffer(
5351        &self,
5352        buffer_id: BufferId,
5353        text_anchors: impl IntoIterator<Item = text::Anchor>,
5354    ) -> Option<impl Iterator<Item = Anchor>> {
5355        let path_key_index = self.path_key_index_for_buffer(buffer_id)?;
5356        Some(
5357            text_anchors
5358                .into_iter()
5359                .map(move |anchor| Anchor::in_buffer(path_key_index, anchor)),
5360        )
5361    }
5362
5363    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5364        match anchor {
5365            // todo(lw): should be `!self.is_empty()`
5366            Anchor::Min | Anchor::Max => true,
5367            Anchor::Excerpt(excerpt_anchor) => {
5368                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5369                    return false;
5370                };
5371                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5372                cursor.seek(&target, Bias::Left);
5373                let Some(excerpt) = cursor.item() else {
5374                    return false;
5375                };
5376                excerpt
5377                    .buffer_snapshot(self)
5378                    .can_resolve(&excerpt_anchor.text_anchor())
5379            }
5380        }
5381    }
5382
5383    pub fn excerpts(&self) -> impl Iterator<Item = (&BufferSnapshot, ExcerptInfo)> {
5384        self.excerpts
5385            .iter()
5386            .map(|excerpt| (excerpt.buffer_snapshot(self), excerpt.info()))
5387    }
5388
5389    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5390    where
5391        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5392        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5393    {
5394        let excerpts = self.excerpts.cursor(());
5395        let diff_transforms = self.diff_transforms.cursor(());
5396        MultiBufferCursor {
5397            excerpts,
5398            diff_transforms,
5399            cached_region: OnceCell::new(),
5400            snapshot: self,
5401        }
5402    }
5403
5404    pub fn excerpt_before(&self, anchor: Anchor) -> Option<ExcerptInfo> {
5405        let target = anchor.try_seek_target(&self)?;
5406        let mut excerpts = self.excerpts.cursor::<ExcerptSummary>(());
5407        excerpts.seek(&target, Bias::Left);
5408        excerpts.prev();
5409        Some(excerpts.item()?.info())
5410    }
5411
5412    pub fn excerpt_boundaries_in_range<R, T>(
5413        &self,
5414        range: R,
5415    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5416    where
5417        R: RangeBounds<T>,
5418        T: ToOffset,
5419    {
5420        let start_offset;
5421        let start = match range.start_bound() {
5422            Bound::Included(start) => {
5423                start_offset = start.to_offset(self);
5424                Bound::Included(start_offset)
5425            }
5426            Bound::Excluded(_) => {
5427                panic!("not supported")
5428            }
5429            Bound::Unbounded => {
5430                start_offset = MultiBufferOffset::ZERO;
5431                Bound::Unbounded
5432            }
5433        };
5434        let end = match range.end_bound() {
5435            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5436            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5437            Bound::Unbounded => Bound::Unbounded,
5438        };
5439        let bounds = (start, end);
5440        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5441        cursor.seek(&DimensionPair {
5442            key: start_offset,
5443            value: None,
5444        });
5445
5446        if cursor
5447            .fetch_excerpt_with_range()
5448            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5449        {
5450            cursor.prev_excerpt();
5451        } else {
5452            cursor.seek_to_start_of_current_excerpt();
5453        }
5454        let mut prev_excerpt = cursor
5455            .fetch_excerpt_with_range()
5456            .map(|(excerpt, _)| excerpt);
5457
5458        cursor.next_excerpt_forwards();
5459
5460        iter::from_fn(move || {
5461            loop {
5462                if self.singleton {
5463                    return None;
5464                }
5465
5466                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5467                cursor.next_excerpt_forwards();
5468                if !bounds.contains(&next_range.start.key) {
5469                    prev_excerpt = Some(next_excerpt);
5470                    continue;
5471                }
5472
5473                let next_region_start = next_range.start.value.unwrap();
5474                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5475                    range.start.value.unwrap()
5476                } else {
5477                    self.max_point()
5478                };
5479
5480                let prev = prev_excerpt.as_ref().map(|excerpt| ExcerptBoundaryInfo {
5481                    path_key_index: excerpt.path_key_index,
5482                    buffer: excerpt.buffer_snapshot(self).clone(),
5483                    range: excerpt.range.clone(),
5484                    end_row: MultiBufferRow(next_region_start.row),
5485                });
5486
5487                let next = ExcerptBoundaryInfo {
5488                    path_key_index: next_excerpt.path_key_index,
5489                    buffer: next_excerpt.buffer_snapshot(self).clone(),
5490                    range: next_excerpt.range.clone(),
5491                    end_row: if next_excerpt.has_trailing_newline {
5492                        MultiBufferRow(next_region_end.row - 1)
5493                    } else {
5494                        MultiBufferRow(next_region_end.row)
5495                    },
5496                };
5497
5498                let row = MultiBufferRow(next_region_start.row);
5499
5500                prev_excerpt = Some(next_excerpt);
5501
5502                return Some(ExcerptBoundary { row, prev, next });
5503            }
5504        })
5505    }
5506
5507    pub fn edit_count(&self) -> usize {
5508        self.edit_count
5509    }
5510
5511    pub fn non_text_state_update_count(&self) -> usize {
5512        self.non_text_state_update_count
5513    }
5514
5515    /// Returns the smallest enclosing bracket ranges containing the given range or
5516    /// None if no brackets contain range or the range is not contained in a single
5517    /// excerpt
5518    ///
5519    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5520    #[ztracing::instrument(skip_all)]
5521    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5522        &self,
5523        range: Range<T>,
5524        range_filter: Option<
5525            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5526        >,
5527    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5528        let range = range.start.to_offset(self)..range.end.to_offset(self);
5529        let mut excerpt = self.excerpt_containing(range.clone())?;
5530        let buffer_snapshot = excerpt.buffer(self).clone();
5531        let excerpt_buffer_range = excerpt.buffer_range(self);
5532
5533        // Filter to ranges contained in the excerpt
5534        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5535            excerpt_buffer_range.contains(&BufferOffset(open.start))
5536                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5537                && range_filter.is_none_or(|filter| {
5538                    filter(
5539                        &buffer_snapshot,
5540                        BufferOffset(open.start)..BufferOffset(close.end),
5541                        BufferOffset(close.start)..BufferOffset(close.end),
5542                    )
5543                })
5544        };
5545
5546        let (open, close) = buffer_snapshot.innermost_enclosing_bracket_ranges(
5547            excerpt.map_range_to_buffer(range),
5548            Some(&range_filter),
5549        )?;
5550
5551        Some((
5552            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5553            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5554        ))
5555    }
5556
5557    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5558    /// not contained in a single excerpt
5559    pub fn enclosing_bracket_ranges<T: ToOffset>(
5560        &self,
5561        range: Range<T>,
5562    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5563    {
5564        let range = range.start.to_offset(self)..range.end.to_offset(self);
5565        let mut excerpt = self.excerpt_containing(range.clone())?;
5566
5567        Some(
5568            excerpt
5569                .buffer(self)
5570                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5571                .filter_map(move |pair| {
5572                    let open_range =
5573                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5574                    let close_range =
5575                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5576                    if excerpt.contains_buffer_range(open_range.start..close_range.end, self) {
5577                        Some((
5578                            excerpt.map_range_from_buffer(open_range),
5579                            excerpt.map_range_from_buffer(close_range),
5580                        ))
5581                    } else {
5582                        None
5583                    }
5584                }),
5585        )
5586    }
5587
5588    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5589    /// not contained in a single excerpt
5590    pub fn text_object_ranges<T: ToOffset>(
5591        &self,
5592        range: Range<T>,
5593        options: TreeSitterOptions,
5594    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5595        let range = range.start.to_offset(self)..range.end.to_offset(self);
5596        self.excerpt_containing(range.clone())
5597            .map(|mut excerpt| {
5598                excerpt
5599                    .buffer(self)
5600                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5601                    .filter_map(move |(range, text_object)| {
5602                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5603                        if excerpt.contains_buffer_range(range.clone(), self) {
5604                            Some((excerpt.map_range_from_buffer(range), text_object))
5605                        } else {
5606                            None
5607                        }
5608                    })
5609            })
5610            .into_iter()
5611            .flatten()
5612    }
5613
5614    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5615    /// not contained in a single excerpt
5616    pub fn bracket_ranges<T: ToOffset>(
5617        &self,
5618        range: Range<T>,
5619    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5620    {
5621        let range = range.start.to_offset(self)..range.end.to_offset(self);
5622        let mut excerpt = self.excerpt_containing(range.clone())?;
5623        Some(
5624            excerpt
5625                .buffer(self)
5626                .bracket_ranges(excerpt.map_range_to_buffer(range))
5627                .filter_map(move |pair| {
5628                    let open_range =
5629                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5630                    let close_range =
5631                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5632                    excerpt
5633                        .contains_buffer_range(open_range.start..close_range.end, self)
5634                        .then(|| BracketMatch {
5635                            open_range: excerpt.map_range_from_buffer(open_range),
5636                            close_range: excerpt.map_range_from_buffer(close_range),
5637                            color_index: pair.color_index,
5638                            newline_only: pair.newline_only,
5639                            syntax_layer_depth: pair.syntax_layer_depth,
5640                        })
5641                })
5642                .map(BracketMatch::bracket_ranges),
5643        )
5644    }
5645
5646    pub fn redacted_ranges<'a, T: ToOffset>(
5647        &'a self,
5648        range: Range<T>,
5649        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5650    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5651        let range = range.start.to_offset(self)..range.end.to_offset(self);
5652        self.lift_buffer_metadata(range, move |buffer, range| {
5653            if redaction_enabled(buffer.file()) {
5654                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5655            } else {
5656                None
5657            }
5658        })
5659        .map(|(range, _, _)| range)
5660    }
5661
5662    pub fn runnable_ranges(
5663        &self,
5664        range: Range<Anchor>,
5665    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5666        let range = range.start.to_offset(self)..range.end.to_offset(self);
5667        self.lift_buffer_metadata(range, move |buffer, range| {
5668            Some(
5669                buffer
5670                    .runnable_ranges(range.clone())
5671                    .filter(move |runnable| {
5672                        runnable.run_range.start >= range.start
5673                            && runnable.run_range.end < range.end
5674                    })
5675                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5676            )
5677        })
5678        .map(|(run_range, runnable, _)| (run_range, runnable))
5679    }
5680
5681    pub fn line_indents(
5682        &self,
5683        start_row: MultiBufferRow,
5684        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5685    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5686        let max_point = self.max_point();
5687        let mut cursor = self.cursor::<Point, Point>();
5688        cursor.seek(&Point::new(start_row.0, 0));
5689        iter::from_fn(move || {
5690            let mut region = cursor.region()?;
5691            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5692                cursor.next();
5693                region = cursor.region()?;
5694            }
5695            let region = cursor.region()?;
5696            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5697            let buffer_start_row =
5698                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5699
5700            let buffer_end_row = if region.is_main_buffer
5701                && (region.has_trailing_newline || region.range.end == max_point)
5702            {
5703                region.buffer_range.end.row
5704            } else {
5705                region.buffer_range.end.row.saturating_sub(1)
5706            };
5707
5708            let line_indents = region
5709                .buffer
5710                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5711            let region_buffer_row = region.buffer_range.start.row;
5712            let region_row = region.range.start.row;
5713            let region_buffer = region.excerpt.buffer_snapshot(self);
5714            cursor.next();
5715            Some(line_indents.map(move |(buffer_row, indent)| {
5716                let row = region_row + (buffer_row - region_buffer_row);
5717                (MultiBufferRow(row), indent, region_buffer)
5718            }))
5719        })
5720        .flatten()
5721    }
5722
5723    pub fn reversed_line_indents(
5724        &self,
5725        end_row: MultiBufferRow,
5726        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5727    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5728        let max_point = self.max_point();
5729        let mut cursor = self.cursor::<Point, Point>();
5730        cursor.seek(&Point::new(end_row.0, 0));
5731        iter::from_fn(move || {
5732            let mut region = cursor.region()?;
5733            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5734                cursor.prev();
5735                region = cursor.region()?;
5736            }
5737            let region = cursor.region()?;
5738
5739            let buffer_start_row = region.buffer_range.start.row;
5740            let buffer_end_row = if region.is_main_buffer
5741                && (region.has_trailing_newline || region.range.end == max_point)
5742            {
5743                region.buffer_range.end.row + 1
5744            } else {
5745                region.buffer_range.end.row
5746            };
5747
5748            let overshoot = end_row.0 - region.range.start.row;
5749            let buffer_end_row =
5750                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5751
5752            let line_indents = region
5753                .buffer
5754                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5755            let region_buffer_row = region.buffer_range.start.row;
5756            let region_row = region.range.start.row;
5757            let region_buffer = region.excerpt.buffer_snapshot(self);
5758            cursor.prev();
5759            Some(line_indents.map(move |(buffer_row, indent)| {
5760                let row = region_row + (buffer_row - region_buffer_row);
5761                (MultiBufferRow(row), indent, region_buffer)
5762            }))
5763        })
5764        .flatten()
5765    }
5766
5767    pub async fn enclosing_indent(
5768        &self,
5769        mut target_row: MultiBufferRow,
5770    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5771        let max_row = MultiBufferRow(self.max_point().row);
5772        if target_row >= max_row {
5773            return None;
5774        }
5775
5776        let mut target_indent = self.line_indent_for_row(target_row);
5777
5778        // If the current row is at the start of an indented block, we want to return this
5779        // block as the enclosing indent.
5780        if !target_indent.is_line_empty() && target_row < max_row {
5781            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5782            if !next_line_indent.is_line_empty()
5783                && target_indent.raw_len() < next_line_indent.raw_len()
5784            {
5785                target_indent = next_line_indent;
5786                target_row.0 += 1;
5787            }
5788        }
5789
5790        const SEARCH_ROW_LIMIT: u32 = 25000;
5791        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5792        const YIELD_INTERVAL: u32 = 100;
5793
5794        let mut accessed_row_counter = 0;
5795
5796        // If there is a blank line at the current row, search for the next non indented lines
5797        if target_indent.is_line_empty() {
5798            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5799            let end =
5800                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5801
5802            let mut non_empty_line_above = None;
5803            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5804                if row < start {
5805                    break;
5806                }
5807                accessed_row_counter += 1;
5808                if accessed_row_counter == YIELD_INTERVAL {
5809                    accessed_row_counter = 0;
5810                    yield_now().await;
5811                }
5812                if !indent.is_line_empty() {
5813                    non_empty_line_above = Some((row, indent));
5814                    break;
5815                }
5816            }
5817
5818            let mut non_empty_line_below = None;
5819            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5820                if row > end {
5821                    break;
5822                }
5823                accessed_row_counter += 1;
5824                if accessed_row_counter == YIELD_INTERVAL {
5825                    accessed_row_counter = 0;
5826                    yield_now().await;
5827                }
5828                if !indent.is_line_empty() {
5829                    non_empty_line_below = Some((row, indent));
5830                    break;
5831                }
5832            }
5833
5834            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5835                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5836                    if above_indent.raw_len() >= below_indent.raw_len() {
5837                        (above_row, above_indent)
5838                    } else {
5839                        (below_row, below_indent)
5840                    }
5841                }
5842                (Some(above), None) => above,
5843                (None, Some(below)) => below,
5844                _ => return None,
5845            };
5846
5847            target_indent = indent;
5848            target_row = row;
5849        }
5850
5851        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5852        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5853
5854        let mut start_indent = None;
5855        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5856            if row < start {
5857                break;
5858            }
5859            accessed_row_counter += 1;
5860            if accessed_row_counter == YIELD_INTERVAL {
5861                accessed_row_counter = 0;
5862                yield_now().await;
5863            }
5864            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5865                start_indent = Some((row, indent));
5866                break;
5867            }
5868        }
5869        let (start_row, start_indent_size) = start_indent?;
5870
5871        let mut end_indent = (end, None);
5872        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5873            if row > end {
5874                break;
5875            }
5876            accessed_row_counter += 1;
5877            if accessed_row_counter == YIELD_INTERVAL {
5878                accessed_row_counter = 0;
5879                yield_now().await;
5880            }
5881            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5882                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5883                break;
5884            }
5885        }
5886        let (end_row, end_indent_size) = end_indent;
5887
5888        let indent = if let Some(end_indent_size) = end_indent_size {
5889            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5890                start_indent_size
5891            } else {
5892                end_indent_size
5893            }
5894        } else {
5895            start_indent_size
5896        };
5897
5898        Some((start_row..end_row, indent))
5899    }
5900
5901    pub fn indent_guides_in_range<T: ToPoint>(
5902        &self,
5903        range: Range<T>,
5904        ignore_disabled_for_language: bool,
5905        cx: &App,
5906    ) -> impl Iterator<Item = IndentGuide> {
5907        let range = range.start.to_point(self)..range.end.to_point(self);
5908        let start_row = MultiBufferRow(range.start.row);
5909        let end_row = MultiBufferRow(range.end.row);
5910
5911        let mut row_indents = self.line_indents(start_row, |buffer| {
5912            let settings =
5913                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5914            settings.indent_guides.enabled || ignore_disabled_for_language
5915        });
5916
5917        let mut result = Vec::new();
5918        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5919
5920        let mut prev_settings = None;
5921        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5922            if first_row > end_row {
5923                break;
5924            }
5925            let current_depth = indent_stack.len() as u32;
5926
5927            // Avoid retrieving the language settings repeatedly for every buffer row.
5928            if let Some((prev_buffer_id, _)) = &prev_settings
5929                && prev_buffer_id != &buffer.remote_id()
5930            {
5931                prev_settings.take();
5932            }
5933            let settings = &prev_settings
5934                .get_or_insert_with(|| {
5935                    (
5936                        buffer.remote_id(),
5937                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5938                    )
5939                })
5940                .1;
5941            let tab_size = settings.tab_size.get();
5942
5943            // When encountering empty, continue until found useful line indent
5944            // then add to the indent stack with the depth found
5945            let mut found_indent = false;
5946            let mut last_row = first_row;
5947            if line_indent.is_line_blank() {
5948                while !found_indent {
5949                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5950                        break;
5951                    };
5952                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5953                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5954                        break;
5955                    }
5956
5957                    if new_line_indent.is_line_blank() {
5958                        continue;
5959                    }
5960                    last_row = target_row.min(end_row);
5961                    line_indent = new_line_indent;
5962                    found_indent = true;
5963                    break;
5964                }
5965            } else {
5966                found_indent = true
5967            }
5968
5969            let depth = if found_indent {
5970                line_indent.len(tab_size) / tab_size
5971            } else {
5972                0
5973            };
5974
5975            match depth.cmp(&current_depth) {
5976                cmp::Ordering::Less => {
5977                    for _ in 0..(current_depth - depth) {
5978                        let mut indent = indent_stack.pop().unwrap();
5979                        if last_row != first_row {
5980                            // In this case, we landed on an empty row, had to seek forward,
5981                            // and discovered that the indent we where on is ending.
5982                            // This means that the last display row must
5983                            // be on line that ends this indent range, so we
5984                            // should display the range up to the first non-empty line
5985                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5986                        }
5987
5988                        result.push(indent)
5989                    }
5990                }
5991                cmp::Ordering::Greater => {
5992                    for next_depth in current_depth..depth {
5993                        indent_stack.push(IndentGuide {
5994                            buffer_id: buffer.remote_id(),
5995                            start_row: first_row,
5996                            end_row: last_row,
5997                            depth: next_depth,
5998                            tab_size,
5999                            settings: settings.indent_guides.clone(),
6000                        });
6001                    }
6002                }
6003                _ => {}
6004            }
6005
6006            for indent in indent_stack.iter_mut() {
6007                indent.end_row = last_row;
6008            }
6009        }
6010
6011        result.extend(indent_stack);
6012        result.into_iter()
6013    }
6014
6015    pub fn trailing_excerpt_update_count(&self) -> usize {
6016        self.trailing_excerpt_update_count
6017    }
6018
6019    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6020        self.point_to_buffer_offset(point)
6021            .and_then(|(buffer, _)| buffer.file())
6022    }
6023
6024    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6025        self.point_to_buffer_offset(offset)
6026            .and_then(|(buffer, offset)| buffer.language_at(offset))
6027    }
6028
6029    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6030        self.excerpts
6031            .first()
6032            .map(|excerpt| excerpt.buffer_snapshot(self))
6033            .map(|buffer| {
6034                language_settings(
6035                    buffer.language().map(|language| language.name()),
6036                    buffer.file(),
6037                    cx,
6038                )
6039            })
6040            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6041    }
6042
6043    pub fn language_settings_at<'a, T: ToOffset>(
6044        &'a self,
6045        point: T,
6046        cx: &'a App,
6047    ) -> Cow<'a, LanguageSettings> {
6048        let mut language = None;
6049        let mut file = None;
6050        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6051            language = buffer.language_at(offset);
6052            file = buffer.file();
6053        }
6054        language_settings(language.map(|l| l.name()), file, cx)
6055    }
6056
6057    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6058        self.point_to_buffer_offset(point)
6059            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6060    }
6061
6062    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6063        self.point_to_buffer_offset(point)
6064            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6065            .unwrap_or_default()
6066    }
6067
6068    pub fn language_indent_size_at<T: ToOffset>(
6069        &self,
6070        position: T,
6071        cx: &App,
6072    ) -> Option<IndentSize> {
6073        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6074        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6075    }
6076
6077    pub fn is_dirty(&self) -> bool {
6078        self.is_dirty
6079    }
6080
6081    pub fn has_deleted_file(&self) -> bool {
6082        self.has_deleted_file
6083    }
6084
6085    pub fn has_conflict(&self) -> bool {
6086        self.has_conflict
6087    }
6088
6089    pub fn has_diagnostics(&self) -> bool {
6090        self.excerpts
6091            .iter()
6092            .any(|excerpt| excerpt.buffer_snapshot(self).has_diagnostics())
6093    }
6094
6095    pub fn diagnostic_group(
6096        &self,
6097        buffer_id: BufferId,
6098        group_id: usize,
6099    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6100        self.lift_buffer_metadata::<Point, _, _>(
6101            Point::zero()..self.max_point(),
6102            move |buffer, range| {
6103                if buffer.remote_id() != buffer_id {
6104                    return None;
6105                };
6106                Some(
6107                    buffer
6108                        .diagnostics_in_range(range, false)
6109                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6110                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6111                )
6112            },
6113        )
6114        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6115    }
6116
6117    pub fn diagnostics_in_range<'a, MBD>(
6118        &'a self,
6119        range: Range<MBD>,
6120    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6121    where
6122        MBD::TextDimension: 'a
6123            + text::ToOffset
6124            + text::FromAnchor
6125            + Sub<Output = MBD::TextDimension>
6126            + fmt::Debug
6127            + ops::Add<Output = MBD::TextDimension>
6128            + ops::AddAssign
6129            + Ord,
6130        MBD: MultiBufferDimension
6131            + Ord
6132            + Sub<Output = MBD::TextDimension>
6133            + ops::Add<MBD::TextDimension, Output = MBD>
6134            + ops::AddAssign<MBD::TextDimension>
6135            + 'a,
6136    {
6137        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6138            Some(
6139                buffer
6140                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6141                    .map(|entry| (entry.range, entry.diagnostic)),
6142            )
6143        })
6144        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6145    }
6146
6147    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6148        &'a self,
6149        range: Range<MBD>,
6150    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6151    where
6152        MBD: MultiBufferDimension
6153            + Ord
6154            + Sub<Output = MBD::TextDimension>
6155            + ops::Add<MBD::TextDimension, Output = MBD>
6156            + ops::AddAssign<MBD::TextDimension>,
6157        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6158            + ops::Add<Output = MBD::TextDimension>
6159            + text::ToOffset
6160            + text::FromAnchor
6161            + AddAssign<MBD::TextDimension>
6162            + Ord,
6163    {
6164        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6165            Some(
6166                buffer
6167                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6168                    .map(|entry| (entry.range, entry.diagnostic)),
6169            )
6170        })
6171        .map(|(range, diagnostic, excerpt)| {
6172            (
6173                excerpt.buffer_snapshot(self).remote_id(),
6174                DiagnosticEntryRef { diagnostic, range },
6175            )
6176        })
6177    }
6178
6179    pub fn syntax_ancestor<T: ToOffset>(
6180        &self,
6181        range: Range<T>,
6182    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6183        let range = range.start.to_offset(self)..range.end.to_offset(self);
6184        let mut excerpt = self.excerpt_containing(range.clone())?;
6185        let node = excerpt
6186            .buffer(self)
6187            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6188        let node_range = node.byte_range();
6189        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6190        if !excerpt.contains_buffer_range(node_range.clone(), self) {
6191            return None;
6192        };
6193        Some((node, excerpt.map_range_from_buffer(node_range)))
6194    }
6195
6196    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6197        let buffer = self.as_singleton()?;
6198        let outline = buffer.outline(theme);
6199        Some(Outline::new(
6200            outline
6201                .items
6202                .into_iter()
6203                .flat_map(|item| {
6204                    Some(OutlineItem {
6205                        depth: item.depth,
6206                        range: self.anchor_range_in_buffer(buffer.remote_id(), item.range)?,
6207                        source_range_for_text: self.anchor_range_in_buffer(
6208                            buffer.remote_id(),
6209                            item.source_range_for_text,
6210                        )?,
6211                        text: item.text,
6212                        highlight_ranges: item.highlight_ranges,
6213                        name_ranges: item.name_ranges,
6214                        body_range: item.body_range.and_then(|body_range| {
6215                            self.anchor_range_in_buffer(buffer.remote_id(), body_range)
6216                        }),
6217                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6218                            self.anchor_range_in_buffer(buffer.remote_id(), annotation_range)
6219                        }),
6220                    })
6221                })
6222                .collect(),
6223        ))
6224    }
6225
6226    pub fn symbols_containing<T: ToOffset>(
6227        &self,
6228        offset: T,
6229        theme: Option<&SyntaxTheme>,
6230    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6231        let anchor = self.anchor_before(offset);
6232        let target = anchor.try_seek_target(&self)?;
6233        let (_, _, excerpt) = self.excerpts.find((), &target, Bias::Left);
6234        let excerpt = excerpt?;
6235        let buffer_snapshot = excerpt.buffer_snapshot(self);
6236        Some((
6237            buffer_snapshot.remote_id(),
6238            buffer_snapshot
6239                .symbols_containing(
6240                    anchor
6241                        .excerpt_anchor()
6242                        .map(|anchor| anchor.text_anchor())
6243                        .unwrap_or(text::Anchor::min_for_buffer(buffer_snapshot.remote_id())),
6244                    theme,
6245                )
6246                .into_iter()
6247                .flat_map(|item| {
6248                    Some(OutlineItem {
6249                        depth: item.depth,
6250                        source_range_for_text: Anchor::range_in_buffer(
6251                            excerpt.path_key_index,
6252                            item.source_range_for_text,
6253                        ),
6254                        range: Anchor::range_in_buffer(excerpt.path_key_index, item.range),
6255                        text: item.text,
6256                        highlight_ranges: item.highlight_ranges,
6257                        name_ranges: item.name_ranges,
6258                        body_range: item.body_range.map(|body_range| {
6259                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6260                        }),
6261                        annotation_range: item.annotation_range.map(|body_range| {
6262                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6263                        }),
6264                    })
6265                })
6266                .collect(),
6267        ))
6268    }
6269
6270    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6271        let (_, _, excerpt) = self
6272            .excerpts
6273            .find::<ExcerptSummary, _>((), path, Bias::Left);
6274        Some(excerpt?.buffer_snapshot(self))
6275    }
6276
6277    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6278        Some(&self.buffers.get(&buffer_id)?.path_key)
6279    }
6280
6281    pub fn path_key_index_for_buffer(&self, buffer_id: BufferId) -> Option<PathKeyIndex> {
6282        self.first_excerpt_for_buffer(buffer_id)
6283            .map(|excerpt| excerpt.path_key_index)
6284    }
6285
6286    pub fn first_excerpt_for_buffer(&self, buffer_id: BufferId) -> Option<&Excerpt> {
6287        let path_key = &self.buffers.get(&buffer_id)?.path_key;
6288        self.first_excerpt_for_path(path_key)
6289    }
6290
6291    pub fn first_excerpt_for_path(&self, path_key: &PathKey) -> Option<&Excerpt> {
6292        let (_, _, first_excerpt) =
6293            self.excerpts
6294                .find::<ExcerptSummary, _>((), path_key, Bias::Left);
6295        first_excerpt
6296    }
6297
6298    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6299        self.buffer_for_path(self.path_for_buffer(id)?)
6300    }
6301
6302    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6303        self.path_keys_by_index.get(&anchor.path).cloned()
6304    }
6305
6306    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6307        self.try_path_for_anchor(anchor)
6308            .expect("invalid anchor: path was never added to multibuffer")
6309    }
6310
6311    // todo!() this may not make sense any more
6312    pub fn range_for_excerpt(&self, excerpt_id: BufferId) -> Option<Range<Point>> {
6313        todo!()
6314        // let mut cursor = self
6315        //     .excerpts
6316        //     .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6317        // let locator = self.excerpt_locator_for_id(excerpt_id);
6318        // let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6319        // if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6320        //     sought_exact = true;
6321        //     cursor.prev();
6322        // } else if excerpt_id == ExcerptId::min() {
6323        //     sought_exact = true;
6324        // }
6325        // if sought_exact {
6326        //     let start = cursor.start().1;
6327        //     let end = cursor.end().1;
6328        //     let mut diff_transforms = self
6329        //         .diff_transforms
6330        //         .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6331        //     diff_transforms.seek(&start, Bias::Left);
6332        //     let overshoot = start - diff_transforms.start().0;
6333        //     let start = diff_transforms.start().1 + overshoot;
6334        //     diff_transforms.seek(&end, Bias::Right);
6335        //     let overshoot = end - diff_transforms.start().0;
6336        //     let end = diff_transforms.start().1 + overshoot;
6337        //     Some(start.0..end.0)
6338        // } else {
6339        //     None
6340        // }
6341    }
6342
6343    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6344    pub fn excerpt_containing<T: ToOffset>(
6345        &self,
6346        range: Range<T>,
6347    ) -> Option<MultiBufferExcerpt<'_>> {
6348        let range = range.start.to_offset(self)..range.end.to_offset(self);
6349        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6350        cursor.seek(&range.start);
6351
6352        let start_excerpt = cursor.excerpt()?;
6353        if range.end != range.start {
6354            cursor.seek_forward(&range.end);
6355            if cursor.excerpt()? != start_excerpt {
6356                return None;
6357            }
6358        }
6359
6360        cursor.seek_to_start_of_current_excerpt();
6361        let region = cursor.region()?;
6362        let offset = region.range.start;
6363        let buffer_offset = start_excerpt.buffer_start_offset(self);
6364        let excerpt_offset = *cursor.excerpts.start();
6365        Some(MultiBufferExcerpt {
6366            diff_transforms: cursor.diff_transforms,
6367            excerpt: start_excerpt,
6368            offset,
6369            buffer_offset,
6370            excerpt_offset,
6371        })
6372    }
6373
6374    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6375        match anchor {
6376            Anchor::Min => self.excerpts.first().map(|excerpt| excerpt.buffer_id),
6377            Anchor::Excerpt(excerpt_anchor) => Some(excerpt_anchor.text_anchor.buffer_id),
6378            Anchor::Max => self.excerpts.last().map(|excerpt| excerpt.buffer_id),
6379        }
6380    }
6381
6382    pub fn selections_in_range<'a>(
6383        &'a self,
6384        range: &'a Range<Anchor>,
6385        include_local: bool,
6386    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6387        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6388        cursor.seek(&range.start.seek_target(self), Bias::Left);
6389        cursor
6390            .take_while(move |excerpt| {
6391                let excerpt_start =
6392                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6393                excerpt_start.cmp(&range.end, self).is_le()
6394            })
6395            .flat_map(move |excerpt| {
6396                let buffer_snapshot = excerpt.buffer_snapshot(self);
6397                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6398                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6399                    && excerpt.contains(&excerpt_anchor, self)
6400                {
6401                    query_range.start = excerpt_anchor.text_anchor();
6402                }
6403                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6404                    && excerpt.contains(&excerpt_anchor, self)
6405                {
6406                    query_range.end = excerpt_anchor.text_anchor();
6407                }
6408
6409                buffer_snapshot
6410                    .selections_in_range(query_range, include_local)
6411                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6412                        selections.map(move |selection| {
6413                            let mut start =
6414                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6415                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6416                            if range.start.cmp(&start, self).is_gt() {
6417                                start = range.start;
6418                            }
6419                            if range.end.cmp(&end, self).is_lt() {
6420                                end = range.end;
6421                            }
6422
6423                            (
6424                                replica_id,
6425                                line_mode,
6426                                cursor_shape,
6427                                Selection {
6428                                    id: selection.id,
6429                                    start,
6430                                    end,
6431                                    reversed: selection.reversed,
6432                                    goal: selection.goal,
6433                                },
6434                            )
6435                        })
6436                    })
6437            })
6438    }
6439
6440    pub fn show_headers(&self) -> bool {
6441        self.show_headers
6442    }
6443
6444    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6445        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6446    }
6447
6448    pub fn all_diff_hunks_expanded(&self) -> bool {
6449        self.all_diff_hunks_expanded
6450    }
6451
6452    /// Visually annotates a position or range with the `Debug` representation of a value. The
6453    /// callsite of this function is used as a key - previous annotations will be removed.
6454    #[cfg(debug_assertions)]
6455    #[track_caller]
6456    pub fn debug<V, R>(&self, ranges: &R, value: V)
6457    where
6458        R: debug::ToMultiBufferDebugRanges,
6459        V: std::fmt::Debug,
6460    {
6461        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6462    }
6463
6464    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6465    /// debug annotations with the same key will be removed. The key is also used to determine the
6466    /// annotation's color.
6467    #[cfg(debug_assertions)]
6468    #[track_caller]
6469    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6470    where
6471        K: std::hash::Hash + 'static,
6472        R: debug::ToMultiBufferDebugRanges,
6473        V: std::fmt::Debug,
6474    {
6475        let text_ranges = ranges
6476            .to_multi_buffer_debug_ranges(self)
6477            .into_iter()
6478            .flat_map(|range| {
6479                self.range_to_buffer_ranges(range.start..=range.end)
6480                    .into_iter()
6481                    .map(|(buffer, range)| {
6482                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6483                    })
6484            })
6485            .collect();
6486        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6487            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6488        });
6489    }
6490
6491    fn excerpt_edits_for_diff_change(
6492        &self,
6493        path: &PathKey,
6494        diff_change_range: Range<usize>,
6495    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6496        let mut excerpt_edits = Vec::new();
6497        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6498        cursor.seek(path, Bias::Left);
6499        while let Some(excerpt) = cursor.item()
6500            && &excerpt.path_key == path
6501        {
6502            let buffer_snapshot = excerpt.buffer_snapshot(self);
6503            let excerpt_buffer_range = excerpt.range.context.to_offset(buffer_snapshot);
6504            let excerpt_start = cursor.start().clone();
6505            let excerpt_len = excerpt.text_summary.len;
6506            cursor.next();
6507            if diff_change_range.end < excerpt_buffer_range.start
6508                || diff_change_range.start > excerpt_buffer_range.end
6509            {
6510                continue;
6511            }
6512            let diff_change_start_in_excerpt = diff_change_range
6513                .start
6514                .saturating_sub(excerpt_buffer_range.start);
6515            let diff_change_end_in_excerpt = diff_change_range
6516                .end
6517                .saturating_sub(excerpt_buffer_range.start);
6518            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6519            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6520            excerpt_edits.push(Edit {
6521                old: edit_start..edit_end,
6522                new: edit_start..edit_end,
6523            });
6524        }
6525        excerpt_edits
6526    }
6527
6528    fn excerpts_for_path<'a>(
6529        &'a self,
6530        path_key: &'a PathKey,
6531    ) -> impl Iterator<Item = ExcerptInfo> + 'a {
6532        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6533        cursor.seek(path_key, Bias::Left);
6534        cursor
6535            .take_while(move |item| &item.path_key == path_key)
6536            .map(|excerpt| excerpt.info())
6537    }
6538}
6539
6540#[cfg(any(test, feature = "test-support"))]
6541impl MultiBufferSnapshot {
6542    pub fn random_byte_range(
6543        &self,
6544        start_offset: MultiBufferOffset,
6545        rng: &mut impl rand::Rng,
6546    ) -> Range<MultiBufferOffset> {
6547        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6548        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6549        start..end
6550    }
6551
6552    #[cfg(any(test, feature = "test-support"))]
6553    fn check_invariants(&self) {
6554        let excerpts = self.excerpts.items(());
6555
6556        let all_buffer_path_keys =
6557            HashSet::from_iter(self.buffers.values().map(|b| b.path_key.clone()));
6558        let all_excerpt_path_keys = HashSet::from_iter(excerpts.iter().map(|e| e.path_key.clone()));
6559
6560        for (ix, excerpt) in excerpts.iter().enumerate() {
6561            if ix > 0 {
6562                let prev = &excerpts[ix - 1];
6563
6564                if excerpt.path_key < prev.path_key {
6565                    panic!("excerpt path_keys are out-of-order: {:?}", excerpts);
6566                } else if excerpt.path_key == prev.path_key {
6567                    if excerpt
6568                        .start_anchor()
6569                        .cmp(&prev.end_anchor(), &self)
6570                        .is_le()
6571                    {
6572                        panic!("excerpt anchors are out-of-order: {:?}", excerpts);
6573                    }
6574                    if excerpt
6575                        .start_anchor()
6576                        .cmp(&excerpt.end_anchor(), &self)
6577                        .is_ge()
6578                    {
6579                        panic!("excerpt with backward range: {:?}", excerpts);
6580                    }
6581                }
6582            }
6583            assert!(
6584                all_buffer_path_keys.contains(&excerpt.path_key),
6585                "excerpt path key not found in active path keys: {:?}",
6586                excerpt.path_key
6587            );
6588            assert_eq!(
6589                self.path_keys_by_index.get(&excerpt.path_key_index),
6590                Some(&excerpt.path_key),
6591                "excerpt path key index does not match path key: {:?}",
6592                excerpt.path_key,
6593            );
6594        }
6595        assert_eq!(all_buffer_path_keys, all_excerpt_path_keys);
6596
6597        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6598            panic!(
6599                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6600                self.excerpts.summary().text,
6601                self.diff_transforms.summary().input,
6602                self.diff_transforms.items(()),
6603            );
6604        }
6605
6606        let mut prev_transform: Option<&DiffTransform> = None;
6607        for item in self.diff_transforms.iter() {
6608            if let DiffTransform::BufferContent {
6609                summary,
6610                inserted_hunk_info,
6611            } = item
6612            {
6613                if let Some(DiffTransform::BufferContent {
6614                    inserted_hunk_info: prev_inserted_hunk_info,
6615                    ..
6616                }) = prev_transform
6617                    && *inserted_hunk_info == *prev_inserted_hunk_info
6618                {
6619                    panic!(
6620                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6621                        self.diff_transforms.items(())
6622                    );
6623                }
6624                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6625                    panic!("empty buffer content transform");
6626                }
6627            }
6628            prev_transform = Some(item);
6629        }
6630    }
6631}
6632
6633impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6634where
6635    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6636    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6637{
6638    #[instrument(skip_all)]
6639    fn seek(&mut self, position: &MBD) {
6640        let position = OutputDimension(*position);
6641        self.cached_region.take();
6642        self.diff_transforms.seek(&position, Bias::Right);
6643        if self.diff_transforms.item().is_none()
6644            && self.diff_transforms.start().output_dimension == position
6645        {
6646            self.diff_transforms.prev();
6647        }
6648
6649        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6650        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6651            let overshoot = position - self.diff_transforms.start().output_dimension;
6652            excerpt_position += overshoot;
6653        }
6654
6655        self.excerpts.seek(&excerpt_position, Bias::Right);
6656        if self.excerpts.item().is_none() && dbg!(excerpt_position) == *self.excerpts.start() {
6657            dbg!("NONE");
6658            self.excerpts.prev();
6659        }
6660    }
6661
6662    fn seek_forward(&mut self, position: &MBD) {
6663        let position = OutputDimension(*position);
6664        self.cached_region.take();
6665        self.diff_transforms.seek_forward(&position, Bias::Right);
6666        if self.diff_transforms.item().is_none()
6667            && self.diff_transforms.start().output_dimension == position
6668        {
6669            self.diff_transforms.prev();
6670        }
6671
6672        let overshoot = position - self.diff_transforms.start().output_dimension;
6673        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6674        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6675            excerpt_position += overshoot;
6676        }
6677
6678        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6679        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6680            self.excerpts.prev();
6681        }
6682    }
6683
6684    fn next_excerpt(&mut self) {
6685        self.excerpts.next();
6686        self.seek_to_start_of_current_excerpt();
6687    }
6688
6689    fn prev_excerpt(&mut self) {
6690        self.excerpts.prev();
6691        self.seek_to_start_of_current_excerpt();
6692    }
6693
6694    fn seek_to_start_of_current_excerpt(&mut self) {
6695        self.cached_region.take();
6696
6697        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6698            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6699            && self.diff_transforms.next_item().is_some()
6700        {
6701            self.diff_transforms.next();
6702        }
6703    }
6704
6705    fn next_excerpt_forwards(&mut self) {
6706        self.excerpts.next();
6707        self.seek_to_start_of_current_excerpt_forward();
6708    }
6709
6710    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6711        self.cached_region.take();
6712
6713        if self
6714            .diff_transforms
6715            .seek_forward(self.excerpts.start(), Bias::Left)
6716            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6717            && self.diff_transforms.next_item().is_some()
6718        {
6719            self.diff_transforms.next();
6720        }
6721    }
6722
6723    fn next(&mut self) {
6724        self.cached_region.take();
6725        match self
6726            .diff_transforms
6727            .end()
6728            .excerpt_dimension
6729            .cmp(&self.excerpts.end())
6730        {
6731            cmp::Ordering::Less => self.diff_transforms.next(),
6732            cmp::Ordering::Greater => self.excerpts.next(),
6733            cmp::Ordering::Equal => {
6734                self.diff_transforms.next();
6735                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6736                    || self.diff_transforms.item().is_none()
6737                {
6738                    self.excerpts.next();
6739                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6740                    self.diff_transforms.item()
6741                    && self
6742                        .excerpts
6743                        .item()
6744                        .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end)
6745                {
6746                    self.excerpts.next();
6747                }
6748            }
6749        }
6750    }
6751
6752    fn prev(&mut self) {
6753        self.cached_region.take();
6754        match self
6755            .diff_transforms
6756            .start()
6757            .excerpt_dimension
6758            .cmp(self.excerpts.start())
6759        {
6760            cmp::Ordering::Less => self.excerpts.prev(),
6761            cmp::Ordering::Greater => self.diff_transforms.prev(),
6762            cmp::Ordering::Equal => {
6763                self.diff_transforms.prev();
6764                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6765                    || self.diff_transforms.item().is_none()
6766                {
6767                    self.excerpts.prev();
6768                }
6769            }
6770        }
6771    }
6772
6773    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
6774        self.cached_region
6775            .get_or_init(|| self.build_region())
6776            .as_ref()
6777    }
6778
6779    fn is_at_start_of_excerpt(&mut self) -> bool {
6780        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6781            return false;
6782        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6783            return true;
6784        }
6785
6786        self.diff_transforms.prev();
6787        let prev_transform = self.diff_transforms.item();
6788        self.diff_transforms.next();
6789
6790        prev_transform.is_none_or(|next_transform| {
6791            matches!(next_transform, DiffTransform::BufferContent { .. })
6792        })
6793    }
6794
6795    fn is_at_end_of_excerpt(&self) -> bool {
6796        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6797            return false;
6798        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6799            || self.diff_transforms.item().is_none()
6800        {
6801            return true;
6802        }
6803
6804        let next_transform = self.diff_transforms.next_item();
6805        next_transform.is_none_or(|next_transform| match next_transform {
6806            DiffTransform::BufferContent { .. } => true,
6807            DiffTransform::DeletedHunk { hunk_info, .. } => self
6808                .excerpts
6809                .item()
6810                .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end),
6811        })
6812    }
6813
6814    fn main_buffer_position(&self) -> Option<BD> {
6815        let excerpt = self.excerpts.item()?;
6816        let buffer = excerpt.buffer_snapshot(self.snapshot);
6817        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6818        let mut buffer_start = buffer_context_start;
6819        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6820        buffer_start += overshoot;
6821        Some(buffer_start)
6822    }
6823
6824    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6825        let excerpt = self.excerpts.item()?;
6826        dbg!("GOT EXCERPT");
6827        match self.diff_transforms.item()? {
6828            DiffTransform::DeletedHunk {
6829                buffer_id,
6830                base_text_byte_range,
6831                has_trailing_newline,
6832                hunk_info,
6833                ..
6834            } => {
6835                let diff = self.snapshot.diffs.get(buffer_id)?;
6836                let buffer = diff.base_text();
6837                let mut rope_cursor = buffer.as_rope().cursor(0);
6838                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6839                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6840                let mut buffer_end = buffer_start;
6841                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6842                let start = self.diff_transforms.start().output_dimension.0;
6843                let end = self.diff_transforms.end().output_dimension.0;
6844                Some(MultiBufferRegion {
6845                    buffer,
6846                    excerpt,
6847                    has_trailing_newline: *has_trailing_newline,
6848                    is_main_buffer: false,
6849                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6850                        hunk_info.hunk_secondary_status,
6851                    )),
6852                    buffer_range: buffer_start..buffer_end,
6853                    range: start..end,
6854                })
6855            }
6856            DiffTransform::BufferContent {
6857                inserted_hunk_info, ..
6858            } => {
6859                let buffer = excerpt.buffer_snapshot(self.snapshot);
6860                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6861
6862                let mut start = self.diff_transforms.start().output_dimension.0;
6863                let mut buffer_start = buffer_context_start;
6864                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6865                    let overshoot =
6866                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6867                    start += overshoot;
6868                } else {
6869                    let overshoot =
6870                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6871                    buffer_start += overshoot;
6872                }
6873
6874                let mut end;
6875                let mut buffer_end;
6876                let has_trailing_newline;
6877                let transform_end = self.diff_transforms.end();
6878                if transform_end.excerpt_dimension < self.excerpts.end() {
6879                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
6880                    end = transform_end.output_dimension.0;
6881                    buffer_end = buffer_context_start;
6882                    buffer_end += overshoot;
6883                    has_trailing_newline = false;
6884                } else {
6885                    let overshoot =
6886                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6887                    end = self.diff_transforms.start().output_dimension.0;
6888                    end += overshoot;
6889                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6890                    has_trailing_newline = excerpt.has_trailing_newline;
6891                };
6892
6893                let diff_hunk_status = inserted_hunk_info.map(|info| {
6894                    if info.is_logically_deleted {
6895                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6896                    } else {
6897                        DiffHunkStatus::added(info.hunk_secondary_status)
6898                    }
6899                });
6900
6901                Some(MultiBufferRegion {
6902                    buffer,
6903                    excerpt,
6904                    has_trailing_newline,
6905                    is_main_buffer: true,
6906                    diff_hunk_status,
6907                    buffer_range: buffer_start..buffer_end,
6908                    range: start..end,
6909                })
6910            }
6911        }
6912    }
6913
6914    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
6915        let excerpt = self.excerpts.item()?;
6916        match self.diff_transforms.item()? {
6917            &DiffTransform::DeletedHunk { .. } => {
6918                let start = self.diff_transforms.start().output_dimension.0;
6919                let end = self.diff_transforms.end().output_dimension.0;
6920                Some((excerpt, start..end))
6921            }
6922            DiffTransform::BufferContent { .. } => {
6923                let mut start = self.diff_transforms.start().output_dimension.0;
6924                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6925                    let overshoot =
6926                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6927                    start += overshoot;
6928                }
6929
6930                let mut end;
6931                let transform_end = self.diff_transforms.end();
6932                if transform_end.excerpt_dimension < self.excerpts.end() {
6933                    end = transform_end.output_dimension.0;
6934                } else {
6935                    let overshoot =
6936                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6937                    end = self.diff_transforms.start().output_dimension.0;
6938                    end += overshoot;
6939                };
6940
6941                Some((excerpt, start..end))
6942            }
6943        }
6944    }
6945
6946    fn excerpt(&self) -> Option<&'a Excerpt> {
6947        self.excerpts.item()
6948    }
6949}
6950
6951impl Excerpt {
6952    fn new(
6953        path_key: PathKey,
6954        path_key_index: PathKeyIndex,
6955        buffer_snapshot: &BufferSnapshot,
6956        range: ExcerptRange<text::Anchor>,
6957        has_trailing_newline: bool,
6958    ) -> Self {
6959        dbg!(&path_key, &range, has_trailing_newline);
6960        Excerpt {
6961            path_key,
6962            path_key_index,
6963            buffer_id: buffer_snapshot.remote_id(),
6964            max_buffer_row: range.context.end.to_point(&buffer_snapshot).row,
6965            text_summary: buffer_snapshot.text_summary_for_range::<TextSummary, _>(
6966                range.context.to_offset(&buffer_snapshot),
6967            ),
6968            range,
6969            has_trailing_newline,
6970        }
6971    }
6972
6973    fn buffer_snapshot<'a>(&self, snapshot: &'a MultiBufferSnapshot) -> &'a BufferSnapshot {
6974        &snapshot
6975            .buffers
6976            .get(&self.buffer_id)
6977            .expect("buffer snapshot not found for excerpt")
6978            .buffer_snapshot
6979    }
6980
6981    fn buffer(&self, multibuffer: &MultiBuffer) -> Entity<Buffer> {
6982        multibuffer
6983            .buffer(self.buffer_id)
6984            .expect("buffer entity not found for excerpt")
6985    }
6986
6987    fn info(&self) -> ExcerptInfo {
6988        ExcerptInfo {
6989            path_key_index: self.path_key_index,
6990            buffer_id: self.buffer_id,
6991            range: self.range.clone(),
6992        }
6993    }
6994
6995    fn chunks_in_range<'a>(
6996        &'a self,
6997        range: Range<usize>,
6998        language_aware: bool,
6999        snapshot: &'a MultiBufferSnapshot,
7000    ) -> ExcerptChunks<'a> {
7001        let buffer = self.buffer_snapshot(snapshot);
7002        let content_start = self.range.context.start.to_offset(buffer);
7003        let chunks_start = content_start + range.start;
7004        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7005
7006        let has_footer = self.has_trailing_newline
7007            && range.start <= self.text_summary.len
7008            && range.end > self.text_summary.len;
7009
7010        let content_chunks = buffer.chunks(chunks_start..chunks_end, language_aware);
7011
7012        ExcerptChunks {
7013            content_chunks,
7014            has_footer,
7015            end: self.end_anchor(),
7016        }
7017    }
7018
7019    fn seek_chunks(
7020        &self,
7021        excerpt_chunks: &mut ExcerptChunks,
7022        range: Range<usize>,
7023        snapshot: &MultiBufferSnapshot,
7024    ) {
7025        let buffer = self.buffer_snapshot(snapshot);
7026        let content_start = self.range.context.start.to_offset(buffer);
7027        let chunks_start = content_start + range.start;
7028        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7029        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7030        excerpt_chunks.has_footer = self.has_trailing_newline
7031            && range.start <= self.text_summary.len
7032            && range.end > self.text_summary.len;
7033    }
7034
7035    fn clip_anchor(
7036        &self,
7037        text_anchor: text::Anchor,
7038        snapshot: &MultiBufferSnapshot,
7039    ) -> text::Anchor {
7040        let buffer = self.buffer_snapshot(snapshot);
7041        if text_anchor.cmp(&self.range.context.start, buffer).is_lt() {
7042            self.range.context.start
7043        } else if text_anchor.cmp(&self.range.context.end, buffer).is_gt() {
7044            self.range.context.end
7045        } else {
7046            text_anchor
7047        }
7048    }
7049
7050    pub(crate) fn contains(&self, anchor: &ExcerptAnchor, snapshot: &MultiBufferSnapshot) -> bool {
7051        self.path_key_index == anchor.path
7052            && self.buffer_id == anchor.text_anchor.buffer_id
7053            && self
7054                .range
7055                .contains(&anchor.text_anchor(), self.buffer_snapshot(snapshot))
7056    }
7057
7058    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7059    fn buffer_start_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7060        BufferOffset(
7061            self.range
7062                .context
7063                .start
7064                .to_offset(self.buffer_snapshot(snapshot)),
7065        )
7066    }
7067
7068    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7069    fn buffer_end_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7070        self.buffer_start_offset(snapshot) + self.text_summary.len
7071    }
7072
7073    fn start_anchor(&self) -> ExcerptAnchor {
7074        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.start)
7075    }
7076
7077    fn end_anchor(&self) -> ExcerptAnchor {
7078        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.end)
7079    }
7080}
7081
7082impl PartialEq for Excerpt {
7083    fn eq(&self, other: &Self) -> bool {
7084        self.path_key_index == other.path_key_index
7085            && self.buffer_id == other.buffer_id
7086            && self.range.context == other.range.context
7087    }
7088}
7089
7090impl<'a> MultiBufferExcerpt<'a> {
7091    pub fn buffer_id(&self) -> BufferId {
7092        self.excerpt.buffer_id
7093    }
7094
7095    pub fn start_anchor(&self) -> Anchor {
7096        Anchor::in_buffer(
7097            self.excerpt.path_key_index,
7098            self.excerpt.range.context.start,
7099        )
7100    }
7101
7102    pub fn end_anchor(&self) -> Anchor {
7103        Anchor::in_buffer(self.excerpt.path_key_index, self.excerpt.range.context.end)
7104    }
7105
7106    pub fn buffer<'b>(&self, snapshot: &'b MultiBufferSnapshot) -> &'b BufferSnapshot {
7107        self.excerpt.buffer_snapshot(snapshot)
7108    }
7109
7110    pub fn buffer_range(&self, snapshot: &'a MultiBufferSnapshot) -> Range<BufferOffset> {
7111        self.buffer_offset
7112            ..BufferOffset(
7113                self.excerpt
7114                    .range
7115                    .context
7116                    .end
7117                    .to_offset(&self.excerpt.buffer_snapshot(snapshot).text),
7118            )
7119    }
7120
7121    pub fn start_offset(&self) -> MultiBufferOffset {
7122        self.offset
7123    }
7124
7125    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7126    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7127        self.map_range_to_buffer(offset..offset).start
7128    }
7129
7130    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7131    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7132        self.diff_transforms
7133            .seek(&OutputDimension(range.start), Bias::Right);
7134        let start = self.map_offset_to_buffer_internal(range.start);
7135        let end = if range.end > range.start {
7136            self.diff_transforms
7137                .seek_forward(&OutputDimension(range.end), Bias::Right);
7138            self.map_offset_to_buffer_internal(range.end)
7139        } else {
7140            start
7141        };
7142        start..end
7143    }
7144
7145    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7146        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7147        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7148            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7149        };
7150        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7151        self.buffer_offset + offset_in_excerpt
7152    }
7153
7154    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7155    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7156        self.map_range_from_buffer(buffer_offset..buffer_offset)
7157            .start
7158    }
7159
7160    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7161    pub fn map_range_from_buffer(
7162        &mut self,
7163        buffer_range: Range<BufferOffset>,
7164    ) -> Range<MultiBufferOffset> {
7165        if buffer_range.start < self.buffer_offset {
7166            log::warn!(
7167                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7168            );
7169            return self.offset..self.offset;
7170        }
7171        let overshoot = buffer_range.start - self.buffer_offset;
7172        let excerpt_offset = self.excerpt_offset + overshoot;
7173        let excerpt_seek_dim = excerpt_offset;
7174        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7175        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7176            log::warn!(
7177                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7178            );
7179            return self.offset..self.offset;
7180        }
7181        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7182        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7183
7184        let end = if buffer_range.start < buffer_range.end {
7185            let overshoot = buffer_range.end - self.buffer_offset;
7186            let excerpt_offset = self.excerpt_offset + overshoot;
7187            let excerpt_seek_dim = excerpt_offset;
7188            self.diff_transforms
7189                .seek_forward(&excerpt_seek_dim, Bias::Right);
7190            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7191            // todo(lw): Clamp end to the excerpt boundaries
7192            self.diff_transforms.start().output_dimension.0 + overshoot
7193        } else {
7194            start
7195        };
7196
7197        start..end
7198    }
7199
7200    /// Returns true if the entirety of the given range is in the buffer's excerpt
7201    pub fn contains_buffer_range(
7202        &self,
7203        range: Range<BufferOffset>,
7204        snapshot: &MultiBufferSnapshot,
7205    ) -> bool {
7206        range.start >= self.excerpt.buffer_start_offset(snapshot)
7207            && range.end <= self.excerpt.buffer_end_offset(snapshot)
7208    }
7209
7210    /// Returns true if any part of the given range is in the buffer's excerpt
7211    pub fn contains_partial_buffer_range(
7212        &self,
7213        range: Range<BufferOffset>,
7214        snapshot: &MultiBufferSnapshot,
7215    ) -> bool {
7216        range.start <= self.excerpt.buffer_end_offset(snapshot)
7217            && range.end >= self.excerpt.buffer_start_offset(snapshot)
7218    }
7219
7220    pub fn max_buffer_row(&self) -> u32 {
7221        self.excerpt.max_buffer_row
7222    }
7223}
7224
7225impl fmt::Debug for Excerpt {
7226    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7227        f.debug_struct("Excerpt")
7228            .field("path_key", &self.path_key)
7229            .field("range", &self.range)
7230            .field("text_summary", &self.text_summary)
7231            .field("has_trailing_newline", &self.has_trailing_newline)
7232            .finish()
7233    }
7234}
7235
7236impl sum_tree::Item for Excerpt {
7237    type Summary = ExcerptSummary;
7238
7239    fn summary(&self, _cx: ()) -> Self::Summary {
7240        let mut text = self.text_summary;
7241        if self.has_trailing_newline {
7242            text += TextSummary::from("\n");
7243        }
7244        ExcerptSummary {
7245            path_key: self.path_key.clone(),
7246            max_anchor: Some(self.range.context.end),
7247            widest_line_number: self.max_buffer_row,
7248            text: text.into(),
7249            count: 1,
7250        }
7251    }
7252}
7253
7254impl DiffTransform {
7255    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7256        match self {
7257            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7258            DiffTransform::BufferContent {
7259                inserted_hunk_info, ..
7260            } => *inserted_hunk_info,
7261        }
7262    }
7263}
7264
7265impl sum_tree::Item for DiffTransform {
7266    type Summary = DiffTransformSummary;
7267
7268    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7269        match self {
7270            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7271                input: *summary,
7272                output: *summary,
7273            },
7274            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7275                input: MBTextSummary::default(),
7276                output: summary.into(),
7277            },
7278        }
7279    }
7280}
7281
7282impl DiffTransformSummary {
7283    fn excerpt_len(&self) -> ExcerptOffset {
7284        ExcerptDimension(self.input.len)
7285    }
7286}
7287
7288impl sum_tree::ContextLessSummary for DiffTransformSummary {
7289    fn zero() -> Self {
7290        DiffTransformSummary {
7291            input: MBTextSummary::default(),
7292            output: MBTextSummary::default(),
7293        }
7294    }
7295
7296    fn add_summary(&mut self, other: &Self) {
7297        self.input += other.input;
7298        self.output += other.output;
7299    }
7300}
7301
7302impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7303    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7304        PathKey::min()
7305    }
7306
7307    fn add_summary(
7308        &mut self,
7309        summary: &'_ ExcerptSummary,
7310        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7311    ) {
7312        *self = summary.path_key.clone();
7313    }
7314}
7315
7316impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7317    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7318        MultiBufferOffset::ZERO
7319    }
7320
7321    fn add_summary(
7322        &mut self,
7323        summary: &'_ ExcerptSummary,
7324        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7325    ) {
7326        *self += summary.text.len
7327    }
7328}
7329
7330impl sum_tree::ContextLessSummary for ExcerptSummary {
7331    fn zero() -> Self {
7332        Self::min()
7333    }
7334
7335    fn add_summary(&mut self, summary: &Self) {
7336        debug_assert!(
7337            summary.path_key >= self.path_key,
7338            "Path keys must be in ascending order: {:?} > {:?}",
7339            summary.path_key,
7340            self.path_key
7341        );
7342
7343        self.path_key = summary.path_key.clone();
7344        self.max_anchor = summary.max_anchor;
7345        self.text += summary.text;
7346        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7347        self.count += summary.count;
7348    }
7349}
7350
7351impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7352    fn cmp(
7353        &self,
7354        cursor_location: &ExcerptSummary,
7355        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7356    ) -> cmp::Ordering {
7357        match self {
7358            AnchorSeekTarget::Min => Ordering::Less,
7359            AnchorSeekTarget::Max => Ordering::Greater,
7360            AnchorSeekTarget::Excerpt {
7361                path_key,
7362                anchor,
7363                snapshot,
7364            } => {
7365                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7366                if path_comparison.is_ne() {
7367                    path_comparison
7368                } else if let Some(snapshot) = snapshot {
7369                    // todo!() think more about this..
7370                    // the goal is that if you seek to buffer_id 1 (path key a)
7371                    // and you find that path key a now belongs to buffer_id 2,
7372                    // we'll seek past buffer_id 2.
7373                    if cursor_location.max_anchor.map(|a| a.buffer_id) != Some(snapshot.remote_id())
7374                    {
7375                        Ordering::Greater
7376                    } else {
7377                        anchor
7378                            .text_anchor()
7379                            .cmp(&cursor_location.max_anchor.unwrap(), snapshot)
7380                    }
7381                } else {
7382                    // shouldn't happen because we expect this buffer not to have any excerpts
7383                    // (otherwise snapshot would have been Some)
7384                    Ordering::Equal
7385                }
7386            }
7387        }
7388    }
7389}
7390
7391impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7392    fn cmp(
7393        &self,
7394        cursor_location: &ExcerptSummary,
7395        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7396    ) -> cmp::Ordering {
7397        Ord::cmp(self, &cursor_location.path_key)
7398    }
7399}
7400
7401impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7402where
7403    MBD: MultiBufferDimension + Default,
7404{
7405    fn zero(_: ()) -> Self {
7406        ExcerptDimension(MBD::default())
7407    }
7408
7409    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7410        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7411    }
7412}
7413
7414#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7415struct OutputDimension<T>(T);
7416
7417impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7418    fn eq(&self, other: &T) -> bool {
7419        self.0 == *other
7420    }
7421}
7422
7423impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7424    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7425        self.0.partial_cmp(other)
7426    }
7427}
7428
7429impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7430where
7431    T: ops::Sub<U, Output = R>,
7432{
7433    type Output = R;
7434
7435    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7436        self.0 - other.0
7437    }
7438}
7439
7440impl<R, T, U> ops::Add<U> for OutputDimension<T>
7441where
7442    T: ops::Add<U, Output = R>,
7443{
7444    type Output = OutputDimension<R>;
7445
7446    fn add(self, other: U) -> Self::Output {
7447        OutputDimension(self.0 + other)
7448    }
7449}
7450
7451impl<T, U> AddAssign<U> for OutputDimension<T>
7452where
7453    T: AddAssign<U>,
7454{
7455    fn add_assign(&mut self, other: U) {
7456        self.0 += other;
7457    }
7458}
7459
7460impl<T, U> SubAssign<U> for OutputDimension<T>
7461where
7462    T: SubAssign<U>,
7463{
7464    fn sub_assign(&mut self, other: U) {
7465        self.0 -= other;
7466    }
7467}
7468
7469#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7470struct ExcerptDimension<T>(T);
7471
7472impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7473    fn eq(&self, other: &T) -> bool {
7474        self.0 == *other
7475    }
7476}
7477
7478impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7479    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7480        self.0.partial_cmp(other)
7481    }
7482}
7483
7484impl ExcerptOffset {
7485    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7486        self.0.saturating_sub(other.0)
7487    }
7488}
7489
7490impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7491where
7492    T: ops::Sub<U, Output = R>,
7493{
7494    type Output = R;
7495
7496    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7497        self.0 - other.0
7498    }
7499}
7500
7501impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7502where
7503    T: ops::Add<U, Output = R>,
7504{
7505    type Output = ExcerptDimension<R>;
7506
7507    fn add(self, other: U) -> Self::Output {
7508        ExcerptDimension(self.0 + other)
7509    }
7510}
7511
7512impl<T, U> AddAssign<U> for ExcerptDimension<T>
7513where
7514    T: AddAssign<U>,
7515{
7516    fn add_assign(&mut self, other: U) {
7517        self.0 += other;
7518    }
7519}
7520
7521impl<T, U> SubAssign<U> for ExcerptDimension<T>
7522where
7523    T: SubAssign<U>,
7524{
7525    fn sub_assign(&mut self, other: U) {
7526        self.0 -= other;
7527    }
7528}
7529
7530impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7531    fn zero(_: ()) -> Self {
7532        MultiBufferOffset::ZERO
7533    }
7534
7535    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7536        *self += summary.output.len;
7537    }
7538}
7539
7540impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7541    for ExcerptDimension<MBD>
7542where
7543    MBD: MultiBufferDimension + Ord,
7544{
7545    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7546        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7547    }
7548}
7549
7550impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7551    for ExcerptDimension<MBD>
7552where
7553    MBD: MultiBufferDimension + Ord,
7554{
7555    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7556        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7557    }
7558}
7559
7560impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7561    for ExcerptDimension<MBD>
7562{
7563    fn zero(_: ()) -> Self {
7564        ExcerptDimension(MBD::default())
7565    }
7566
7567    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7568        self.0.add_mb_text_summary(&summary.input)
7569    }
7570}
7571
7572impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7573    for OutputDimension<MBD>
7574where
7575    MBD: MultiBufferDimension + Ord,
7576{
7577    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7578        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7579    }
7580}
7581
7582impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7583    for OutputDimension<MBD>
7584{
7585    fn zero(_: ()) -> Self {
7586        OutputDimension(MBD::default())
7587    }
7588
7589    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7590        self.0.add_mb_text_summary(&summary.output)
7591    }
7592}
7593
7594impl MultiBufferRows<'_> {
7595    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7596        self.point = Point::new(row, 0);
7597        self.cursor.seek(&self.point);
7598    }
7599}
7600
7601impl Iterator for MultiBufferRows<'_> {
7602    type Item = RowInfo;
7603
7604    fn next(&mut self) -> Option<Self::Item> {
7605        if self.is_empty && self.point.row == 0 {
7606            self.point += Point::new(1, 0);
7607            return Some(RowInfo {
7608                buffer_id: None,
7609                buffer_row: Some(0),
7610                multibuffer_row: Some(MultiBufferRow(0)),
7611                diff_status: None,
7612                expand_info: None,
7613                wrapped_buffer_row: None,
7614            });
7615        }
7616
7617        let mut region = self.cursor.region()?.clone();
7618        dbg!("REGION");
7619        while self.point >= region.range.end {
7620            self.cursor.next();
7621            if let Some(next_region) = self.cursor.region() {
7622                region = next_region.clone();
7623            } else if dbg!(self.point) == dbg!(self.cursor.diff_transforms.end().output_dimension.0)
7624            {
7625                let multibuffer_row = MultiBufferRow(self.point.row);
7626                let last_excerpt = self
7627                    .cursor
7628                    .excerpts
7629                    .item()
7630                    .or(self.cursor.excerpts.prev_item())?;
7631                let buffer_snapshot = last_excerpt.buffer_snapshot(self.cursor.snapshot);
7632                let last_row = last_excerpt.range.context.end.to_point(buffer_snapshot).row;
7633
7634                let first_row = last_excerpt
7635                    .range
7636                    .context
7637                    .start
7638                    .to_point(buffer_snapshot)
7639                    .row;
7640
7641                let expand_info = if self.is_singleton {
7642                    None
7643                } else {
7644                    let needs_expand_up = first_row == last_row
7645                        && last_row > 0
7646                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7647                    let needs_expand_down = last_row < buffer_snapshot.max_point().row;
7648
7649                    if needs_expand_up && needs_expand_down {
7650                        Some(ExpandExcerptDirection::UpAndDown)
7651                    } else if needs_expand_up {
7652                        Some(ExpandExcerptDirection::Up)
7653                    } else if needs_expand_down {
7654                        Some(ExpandExcerptDirection::Down)
7655                    } else {
7656                        None
7657                    }
7658                    .map(|direction| ExpandInfo {
7659                        direction,
7660                        excerpt_range: last_excerpt.range.context.clone(),
7661                    })
7662                };
7663                self.point += Point::new(1, 0);
7664                return Some(RowInfo {
7665                    buffer_id: Some(last_excerpt.buffer_id),
7666                    buffer_row: Some(last_row),
7667                    multibuffer_row: Some(multibuffer_row),
7668                    diff_status: None,
7669                    wrapped_buffer_row: None,
7670                    expand_info,
7671                });
7672            } else {
7673                return None;
7674            };
7675        }
7676
7677        let overshoot = self.point - region.range.start;
7678        let buffer_point = region.buffer_range.start + overshoot;
7679        let expand_info = if self.is_singleton {
7680            None
7681        } else {
7682            let needs_expand_up = self.point.row == region.range.start.row
7683                && self.cursor.is_at_start_of_excerpt()
7684                && buffer_point.row > 0;
7685            let needs_expand_down = (region.excerpt.has_trailing_newline
7686                && self.point.row + 1 == region.range.end.row
7687                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7688                && self.cursor.is_at_end_of_excerpt()
7689                && buffer_point.row < region.buffer.max_point().row;
7690
7691            if needs_expand_up && needs_expand_down {
7692                Some(ExpandExcerptDirection::UpAndDown)
7693            } else if needs_expand_up {
7694                Some(ExpandExcerptDirection::Up)
7695            } else if needs_expand_down {
7696                Some(ExpandExcerptDirection::Down)
7697            } else {
7698                None
7699            }
7700            .map(|direction| ExpandInfo {
7701                direction,
7702                excerpt_range: region.excerpt.range.context.clone(),
7703            })
7704        };
7705
7706        let result = Some(RowInfo {
7707            buffer_id: Some(region.buffer.remote_id()),
7708            buffer_row: Some(buffer_point.row),
7709            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7710            diff_status: region
7711                .diff_hunk_status
7712                .filter(|_| self.point < region.range.end),
7713            expand_info,
7714            wrapped_buffer_row: None,
7715        });
7716        self.point += Point::new(1, 0);
7717        result
7718    }
7719}
7720
7721impl<'a> MultiBufferChunks<'a> {
7722    pub fn offset(&self) -> MultiBufferOffset {
7723        self.range.start
7724    }
7725
7726    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7727        self.diff_transforms.seek(&range.end, Bias::Right);
7728        let mut excerpt_end = self.diff_transforms.start().1;
7729        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7730            let overshoot = range.end - self.diff_transforms.start().0;
7731            excerpt_end += overshoot;
7732        }
7733
7734        self.diff_transforms.seek(&range.start, Bias::Right);
7735        let mut excerpt_start = self.diff_transforms.start().1;
7736        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7737            let overshoot = range.start - self.diff_transforms.start().0;
7738            excerpt_start += overshoot;
7739        }
7740
7741        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7742        self.buffer_chunk.take();
7743        self.range = range;
7744    }
7745
7746    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7747        self.excerpt_offset_range = new_range.clone();
7748        self.excerpts.seek(&new_range.start, Bias::Right);
7749        if let Some(excerpt) = self.excerpts.item() {
7750            let excerpt_start = *self.excerpts.start();
7751            if let Some(excerpt_chunks) = self
7752                .excerpt_chunks
7753                .as_mut()
7754                .filter(|chunks| excerpt.end_anchor() == chunks.end)
7755            {
7756                excerpt.seek_chunks(
7757                    excerpt_chunks,
7758                    (self.excerpt_offset_range.start - excerpt_start)
7759                        ..(self.excerpt_offset_range.end - excerpt_start),
7760                    self.snapshot,
7761                );
7762            } else {
7763                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7764                    (self.excerpt_offset_range.start - excerpt_start)
7765                        ..(self.excerpt_offset_range.end - excerpt_start),
7766                    self.language_aware,
7767                    self.snapshot,
7768                ));
7769            }
7770        } else {
7771            self.excerpt_chunks = None;
7772        }
7773    }
7774
7775    #[ztracing::instrument(skip_all)]
7776    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7777        loop {
7778            if self.excerpt_offset_range.is_empty() {
7779                return None;
7780            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7781                self.excerpt_offset_range.start += chunk.text.len();
7782                return Some(chunk);
7783            } else {
7784                self.excerpts.next();
7785                let excerpt = self.excerpts.item()?;
7786                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7787                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7788                    self.language_aware,
7789                    self.snapshot,
7790                ));
7791            }
7792        }
7793    }
7794}
7795
7796impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7797    type Item = &'a str;
7798
7799    fn next(&mut self) -> Option<Self::Item> {
7800        let mut region = self.cursor.region()?;
7801        if self.offset == region.range.start {
7802            self.cursor.prev();
7803            region = self.cursor.region()?;
7804            let start_overshoot = self.start.saturating_sub(region.range.start);
7805            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7806                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7807            ));
7808        }
7809
7810        if self.offset == region.range.end && region.has_trailing_newline {
7811            self.offset -= 1;
7812            Some("\n")
7813        } else {
7814            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7815            self.offset -= chunk.len();
7816            Some(chunk)
7817        }
7818    }
7819}
7820
7821impl<'a> Iterator for MultiBufferChunks<'a> {
7822    type Item = Chunk<'a>;
7823
7824    #[ztracing::instrument(skip_all)]
7825    fn next(&mut self) -> Option<Chunk<'a>> {
7826        if self.range.start >= self.range.end {
7827            return None;
7828        }
7829        if self.range.start == self.diff_transforms.end().0 {
7830            self.diff_transforms.next();
7831        }
7832
7833        let diff_transform_start = self.diff_transforms.start().0;
7834        let diff_transform_end = self.diff_transforms.end().0;
7835        debug_assert!(
7836            self.range.start < diff_transform_end,
7837            "{:?} < {:?} of ({1:?}..{2:?})",
7838            self.range.start,
7839            diff_transform_end,
7840            diff_transform_start
7841        );
7842
7843        let diff_transform = self.diff_transforms.item()?;
7844        match diff_transform {
7845            DiffTransform::BufferContent { .. } => {
7846                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7847                    chunk
7848                } else {
7849                    let chunk = self.next_excerpt_chunk().unwrap();
7850                    self.buffer_chunk.insert(chunk)
7851                };
7852
7853                let chunk_end = self.range.start + chunk.text.len();
7854                let diff_transform_end = diff_transform_end.min(self.range.end);
7855
7856                if diff_transform_end < chunk_end {
7857                    let split_idx = diff_transform_end - self.range.start;
7858                    let (before, after) = chunk.text.split_at(split_idx);
7859                    self.range.start = diff_transform_end;
7860                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7861                    let chars = chunk.chars & mask;
7862                    let tabs = chunk.tabs & mask;
7863                    let newlines = chunk.newlines & mask;
7864
7865                    chunk.text = after;
7866                    chunk.chars = chunk.chars >> split_idx;
7867                    chunk.tabs = chunk.tabs >> split_idx;
7868                    chunk.newlines = chunk.newlines >> split_idx;
7869
7870                    Some(Chunk {
7871                        text: before,
7872                        chars,
7873                        tabs,
7874                        newlines,
7875                        ..chunk.clone()
7876                    })
7877                } else {
7878                    self.range.start = chunk_end;
7879                    self.buffer_chunk.take()
7880                }
7881            }
7882            DiffTransform::DeletedHunk {
7883                buffer_id,
7884                base_text_byte_range,
7885                has_trailing_newline,
7886                ..
7887            } => {
7888                let base_text_start =
7889                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7890                let base_text_end =
7891                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7892                let base_text_end = base_text_end.min(base_text_byte_range.end);
7893
7894                let mut chunks = if let Some((_, mut chunks)) = self
7895                    .diff_base_chunks
7896                    .take()
7897                    .filter(|(id, _)| id == buffer_id)
7898                {
7899                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7900                    {
7901                        chunks.seek(base_text_start..base_text_end);
7902                    }
7903                    chunks
7904                } else {
7905                    let base_buffer = &self.snapshot.diffs.get(buffer_id)?.base_text();
7906                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7907                };
7908
7909                let chunk = if let Some(chunk) = chunks.next() {
7910                    self.range.start += chunk.text.len();
7911                    self.diff_base_chunks = Some((*buffer_id, chunks));
7912                    chunk
7913                } else {
7914                    debug_assert!(has_trailing_newline);
7915                    self.range.start += "\n".len();
7916                    Chunk {
7917                        text: "\n",
7918                        chars: 1u128,
7919                        newlines: 1u128,
7920                        ..Default::default()
7921                    }
7922                };
7923                Some(chunk)
7924            }
7925        }
7926    }
7927}
7928
7929impl MultiBufferBytes<'_> {
7930    fn consume(&mut self, len: usize) {
7931        self.range.start += len;
7932        self.chunk = &self.chunk[len..];
7933
7934        if !self.range.is_empty() && self.chunk.is_empty() {
7935            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7936                self.chunk = chunk;
7937            } else if self.has_trailing_newline {
7938                self.has_trailing_newline = false;
7939                self.chunk = b"\n";
7940            } else {
7941                self.cursor.next();
7942                if let Some(region) = self.cursor.region() {
7943                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7944                        region.buffer_range.start
7945                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7946                                .min(region.buffer_range.end),
7947                    );
7948                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7949                    self.excerpt_bytes = Some(excerpt_bytes);
7950                    self.has_trailing_newline =
7951                        region.has_trailing_newline && self.range.end >= region.range.end;
7952                    if self.chunk.is_empty() && self.has_trailing_newline {
7953                        self.has_trailing_newline = false;
7954                        self.chunk = b"\n";
7955                    }
7956                }
7957            }
7958        }
7959    }
7960}
7961
7962impl<'a> Iterator for MultiBufferBytes<'a> {
7963    type Item = &'a [u8];
7964
7965    fn next(&mut self) -> Option<Self::Item> {
7966        let chunk = self.chunk;
7967        if chunk.is_empty() {
7968            None
7969        } else {
7970            self.consume(chunk.len());
7971            Some(chunk)
7972        }
7973    }
7974}
7975
7976impl io::Read for MultiBufferBytes<'_> {
7977    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7978        let len = cmp::min(buf.len(), self.chunk.len());
7979        buf[..len].copy_from_slice(&self.chunk[..len]);
7980        if len > 0 {
7981            self.consume(len);
7982        }
7983        Ok(len)
7984    }
7985}
7986
7987impl io::Read for ReversedMultiBufferBytes<'_> {
7988    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7989        let len = cmp::min(buf.len(), self.chunk.len());
7990        buf[..len].copy_from_slice(&self.chunk[..len]);
7991        buf[..len].reverse();
7992        if len > 0 {
7993            self.range.end -= len;
7994            self.chunk = &self.chunk[..self.chunk.len() - len];
7995            if !self.range.is_empty()
7996                && self.chunk.is_empty()
7997                && let Some(chunk) = self.chunks.next()
7998            {
7999                self.chunk = chunk.as_bytes();
8000            }
8001        }
8002        Ok(len)
8003    }
8004}
8005
8006impl<'a> Iterator for ExcerptChunks<'a> {
8007    type Item = Chunk<'a>;
8008
8009    fn next(&mut self) -> Option<Self::Item> {
8010        if let Some(chunk) = self.content_chunks.next() {
8011            return Some(chunk);
8012        }
8013
8014        if self.has_footer {
8015            let text = "\n";
8016            let chars = 0b1;
8017            let newlines = 0b1;
8018            self.has_footer = false;
8019            return Some(Chunk {
8020                text,
8021                chars,
8022                newlines,
8023                ..Default::default()
8024            });
8025        }
8026
8027        None
8028    }
8029}
8030
8031impl ToOffset for Point {
8032    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8033        snapshot.point_to_offset(*self)
8034    }
8035    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8036        snapshot.point_to_offset_utf16(*self)
8037    }
8038}
8039
8040impl ToOffset for MultiBufferOffset {
8041    #[track_caller]
8042    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8043        assert!(
8044            *self <= snapshot.len(),
8045            "offset {} is greater than the snapshot.len() {}",
8046            self.0,
8047            snapshot.len().0,
8048        );
8049        *self
8050    }
8051    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8052        snapshot.offset_to_offset_utf16(*self)
8053    }
8054}
8055
8056impl ToOffset for MultiBufferOffsetUtf16 {
8057    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8058        snapshot.offset_utf16_to_offset(*self)
8059    }
8060
8061    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8062        *self
8063    }
8064}
8065
8066impl ToOffset for PointUtf16 {
8067    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8068        snapshot.point_utf16_to_offset(*self)
8069    }
8070    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8071        snapshot.point_utf16_to_offset_utf16(*self)
8072    }
8073}
8074
8075impl ToPoint for MultiBufferOffset {
8076    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8077        snapshot.offset_to_point(*self)
8078    }
8079    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8080        snapshot.offset_to_point_utf16(*self)
8081    }
8082}
8083
8084impl ToPoint for Point {
8085    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8086        *self
8087    }
8088    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8089        snapshot.point_to_point_utf16(*self)
8090    }
8091}
8092
8093impl ToPoint for PointUtf16 {
8094    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8095        snapshot.point_utf16_to_point(*self)
8096    }
8097    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8098        *self
8099    }
8100}
8101
8102#[cfg(debug_assertions)]
8103pub mod debug {
8104    use super::*;
8105
8106    pub trait ToMultiBufferDebugRanges {
8107        fn to_multi_buffer_debug_ranges(
8108            &self,
8109            snapshot: &MultiBufferSnapshot,
8110        ) -> Vec<Range<MultiBufferOffset>>;
8111    }
8112
8113    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8114        fn to_multi_buffer_debug_ranges(
8115            &self,
8116            snapshot: &MultiBufferSnapshot,
8117        ) -> Vec<Range<MultiBufferOffset>> {
8118            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8119        }
8120    }
8121
8122    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8123        fn to_multi_buffer_debug_ranges(
8124            &self,
8125            snapshot: &MultiBufferSnapshot,
8126        ) -> Vec<Range<MultiBufferOffset>> {
8127            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8128                .to_multi_buffer_debug_ranges(snapshot)
8129        }
8130    }
8131
8132    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8133        fn to_multi_buffer_debug_ranges(
8134            &self,
8135            snapshot: &MultiBufferSnapshot,
8136        ) -> Vec<Range<MultiBufferOffset>> {
8137            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8138        }
8139    }
8140
8141    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8142        fn to_multi_buffer_debug_ranges(
8143            &self,
8144            snapshot: &MultiBufferSnapshot,
8145        ) -> Vec<Range<MultiBufferOffset>> {
8146            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8147        }
8148    }
8149
8150    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8151        fn to_multi_buffer_debug_ranges(
8152            &self,
8153            snapshot: &MultiBufferSnapshot,
8154        ) -> Vec<Range<MultiBufferOffset>> {
8155            self.iter()
8156                .map(|item| {
8157                    let offset = item.to_offset(snapshot);
8158                    offset..offset
8159                })
8160                .collect()
8161        }
8162    }
8163
8164    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8165        fn to_multi_buffer_debug_ranges(
8166            &self,
8167            snapshot: &MultiBufferSnapshot,
8168        ) -> Vec<Range<MultiBufferOffset>> {
8169            self.iter()
8170                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8171                .collect()
8172        }
8173    }
8174}