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, Item as _, SumTree, TreeMap};
  55use text::{
  56    AnchorRangeExt as _, 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: Range<text::Anchor>,
 102}
 103
 104impl ExcerptInfo {
 105    pub fn end_anchor(&self) -> Anchor {
 106        Anchor::in_buffer(self.path_key_index, self.range.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.start.cmp(&text_anchor, &snapshot).is_gt() {
1887                found = Some(Anchor::in_buffer(
1888                    excerpt.path_key_index,
1889                    excerpt.range.start,
1890                ));
1891                break;
1892            } else if excerpt.range.end.cmp(&text_anchor, &snapshot).is_ge() {
1893                found = Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
1894                break;
1895            }
1896            found = Some(Anchor::in_buffer(excerpt.path_key_index, excerpt.range.end));
1897        }
1898
1899        found
1900    }
1901
1902    pub fn buffer_anchor_to_anchor(
1903        &self,
1904        // todo(lw): We shouldn't need this?
1905        buffer: &Entity<Buffer>,
1906        anchor: text::Anchor,
1907        cx: &App,
1908    ) -> Option<Anchor> {
1909        let snapshot = buffer.read(cx).snapshot();
1910        for excerpt in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1911            if excerpt.range.contains_anchor(anchor, &snapshot) {
1912                return Some(Anchor::in_buffer(excerpt.path_key_index, anchor));
1913            }
1914        }
1915
1916        None
1917    }
1918
1919    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1920        &self,
1921        anchors: Anchors,
1922        cx: &mut Context<Self>,
1923    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1924        let mut error = None;
1925        let mut futures = Vec::new();
1926        for anchor in anchors {
1927            if let Some(excerpt_anchor) = anchor.excerpt_anchor() {
1928                if let Some(buffer) = self.buffers.get(&excerpt_anchor.text_anchor.buffer_id) {
1929                    buffer.buffer.update(cx, |buffer, _| {
1930                        futures.push(buffer.wait_for_anchors([excerpt_anchor.text_anchor()]))
1931                    });
1932                } else {
1933                    error = Some(anyhow!(
1934                        "buffer {:?} is not part of this multi-buffer",
1935                        excerpt_anchor.text_anchor.buffer_id
1936                    ));
1937                    break;
1938                }
1939            }
1940        }
1941        async move {
1942            if let Some(error) = error {
1943                Err(error)?;
1944            }
1945            for future in futures {
1946                future.await?;
1947            }
1948            Ok(())
1949        }
1950    }
1951
1952    pub fn text_anchor_for_position<T: ToOffset>(
1953        &self,
1954        position: T,
1955        cx: &App,
1956    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1957        let snapshot = self.read(cx);
1958        let anchor = snapshot.anchor_before(position).excerpt_anchor()?;
1959        let buffer = self
1960            .buffers
1961            .get(&anchor.text_anchor.buffer_id)?
1962            .buffer
1963            .clone();
1964        Some((buffer, anchor.text_anchor()))
1965    }
1966
1967    fn on_buffer_event(
1968        &mut self,
1969        buffer: Entity<Buffer>,
1970        event: &language::BufferEvent,
1971        cx: &mut Context<Self>,
1972    ) {
1973        use language::BufferEvent;
1974        let buffer_id = buffer.read(cx).remote_id();
1975        cx.emit(match event {
1976            BufferEvent::Edited => Event::Edited {
1977                edited_buffer: Some(buffer),
1978            },
1979            BufferEvent::DirtyChanged => Event::DirtyChanged,
1980            BufferEvent::Saved => Event::Saved,
1981            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1982            BufferEvent::Reloaded => Event::Reloaded,
1983            BufferEvent::LanguageChanged(has_language) => {
1984                Event::LanguageChanged(buffer_id, *has_language)
1985            }
1986            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1987            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1988            BufferEvent::CapabilityChanged => {
1989                self.capability = buffer.read(cx).capability();
1990                return;
1991            }
1992            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
1993        });
1994    }
1995
1996    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
1997        let diff = diff.read(cx);
1998        let buffer_id = diff.buffer_id;
1999        let diff = DiffStateSnapshot {
2000            diff: diff.snapshot(cx),
2001            main_buffer: None,
2002        };
2003        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2004    }
2005
2006    fn inverted_buffer_diff_language_changed(
2007        &mut self,
2008        diff: Entity<BufferDiff>,
2009        main_buffer: Entity<language::Buffer>,
2010        cx: &mut Context<Self>,
2011    ) {
2012        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2013        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2014        let diff = diff.read(cx);
2015        let diff = DiffStateSnapshot {
2016            diff: diff.snapshot(cx),
2017            main_buffer: Some(main_buffer_snapshot),
2018        };
2019        self.snapshot
2020            .get_mut()
2021            .diffs
2022            .insert(base_text_buffer_id, diff);
2023    }
2024
2025    fn buffer_diff_changed(
2026        &mut self,
2027        diff: Entity<BufferDiff>,
2028        range: Range<text::Anchor>,
2029        cx: &mut Context<Self>,
2030    ) {
2031        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2032            return;
2033        };
2034        let snapshot = self.sync_mut(cx);
2035
2036        let diff = diff.read(cx);
2037        let buffer_id = diff.buffer_id;
2038
2039        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2040            return;
2041        };
2042        let new_diff = DiffStateSnapshot {
2043            diff: diff.snapshot(cx),
2044            main_buffer: None,
2045        };
2046        let base_text_changed = snapshot
2047            .diffs
2048            .get(&buffer_id)
2049            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2050        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2051
2052        let buffer = buffer.read(cx);
2053        let diff_change_range = range.to_offset(buffer);
2054
2055        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2056        let edits = Self::sync_diff_transforms(
2057            snapshot,
2058            excerpt_edits,
2059            DiffChangeKind::DiffUpdated {
2060                base_changed: base_text_changed,
2061            },
2062        );
2063        if !edits.is_empty() {
2064            self.subscriptions.publish(edits);
2065        }
2066        cx.emit(Event::Edited {
2067            edited_buffer: None,
2068        });
2069    }
2070
2071    fn inverted_buffer_diff_changed(
2072        &mut self,
2073        diff: Entity<BufferDiff>,
2074        main_buffer: Entity<language::Buffer>,
2075        diff_change_range: Option<Range<usize>>,
2076        cx: &mut Context<Self>,
2077    ) {
2078        let snapshot = self.sync_mut(cx);
2079
2080        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2081        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2082            return;
2083        };
2084
2085        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2086        let diff = diff.read(cx);
2087        let new_diff = DiffStateSnapshot {
2088            diff: diff.snapshot(cx),
2089            main_buffer: Some(main_buffer_snapshot),
2090        };
2091        snapshot
2092            .diffs
2093            .insert_or_replace(base_text_buffer_id, new_diff);
2094
2095        let Some(diff_change_range) = diff_change_range else {
2096            return;
2097        };
2098
2099        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2100        let edits = Self::sync_diff_transforms(
2101            snapshot,
2102            excerpt_edits,
2103            DiffChangeKind::DiffUpdated {
2104                // We don't read this field for inverted diffs.
2105                base_changed: false,
2106            },
2107        );
2108        if !edits.is_empty() {
2109            self.subscriptions.publish(edits);
2110        }
2111        cx.emit(Event::Edited {
2112            edited_buffer: None,
2113        });
2114    }
2115
2116    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2117        self.buffers.values().map(|state| state.buffer.clone())
2118    }
2119
2120    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2121        self.all_buffers_iter().collect()
2122    }
2123
2124    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2125        self.buffers.keys().copied()
2126    }
2127
2128    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2129        self.all_buffer_ids_iter().collect()
2130    }
2131
2132    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2133        self.buffers
2134            .get(&buffer_id)
2135            .map(|state| state.buffer.clone())
2136    }
2137
2138    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2139        self.point_to_buffer_offset(point, cx)
2140            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2141    }
2142
2143    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2144        let snapshot = self.snapshot(cx);
2145        let buffer = snapshot
2146            .excerpts
2147            .first()
2148            .map(|excerpt| excerpt.buffer(self));
2149        buffer
2150            .map(|buffer| {
2151                let buffer = buffer.read(cx);
2152                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2153            })
2154            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2155    }
2156
2157    pub fn language_settings_at<'a, T: ToOffset>(
2158        &'a self,
2159        point: T,
2160        cx: &'a App,
2161    ) -> Cow<'a, LanguageSettings> {
2162        let mut language = None;
2163        let mut file = None;
2164        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2165            let buffer = buffer.read(cx);
2166            language = buffer.language_at(offset);
2167            file = buffer.file();
2168        }
2169        language_settings(language.map(|l| l.name()), file, cx)
2170    }
2171
2172    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2173        self.buffers.values().for_each(|state| f(&state.buffer))
2174    }
2175
2176    pub fn explicit_title(&self) -> Option<&str> {
2177        self.title.as_deref()
2178    }
2179
2180    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2181        if let Some(title) = self.title.as_ref() {
2182            return title.into();
2183        }
2184
2185        if let Some(buffer) = self.as_singleton() {
2186            let buffer = buffer.read(cx);
2187
2188            if let Some(file) = buffer.file() {
2189                return file.file_name(cx).into();
2190            }
2191
2192            if let Some(title) = self.buffer_content_title(buffer) {
2193                return title;
2194            }
2195        };
2196
2197        "untitled".into()
2198    }
2199
2200    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2201        let mut is_leading_whitespace = true;
2202        let mut count = 0;
2203        let mut prev_was_space = false;
2204        let mut title = String::new();
2205
2206        for ch in buffer.snapshot().chars() {
2207            if is_leading_whitespace && ch.is_whitespace() {
2208                continue;
2209            }
2210
2211            is_leading_whitespace = false;
2212
2213            if ch == '\n' || count >= 40 {
2214                break;
2215            }
2216
2217            if ch.is_whitespace() {
2218                if !prev_was_space {
2219                    title.push(' ');
2220                    count += 1;
2221                    prev_was_space = true;
2222                }
2223            } else {
2224                title.push(ch);
2225                count += 1;
2226                prev_was_space = false;
2227            }
2228        }
2229
2230        let title = title.trim_end().to_string();
2231
2232        if title.is_empty() {
2233            return None;
2234        }
2235
2236        Some(title.into())
2237    }
2238
2239    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2240        self.title = Some(title);
2241        cx.notify();
2242    }
2243
2244    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2245    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2246        for buffer_state in self.buffers.values() {
2247            buffer_state
2248                .buffer
2249                .update(cx, |buffer, _cx| buffer.refresh_preview());
2250        }
2251    }
2252
2253    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2254    pub fn preserve_preview(&self, cx: &App) -> bool {
2255        self.buffers
2256            .values()
2257            .all(|state| state.buffer.read(cx).preserve_preview())
2258    }
2259
2260    #[cfg(any(test, feature = "test-support"))]
2261    pub fn is_parsing(&self, cx: &App) -> bool {
2262        self.as_singleton().unwrap().read(cx).is_parsing()
2263    }
2264
2265    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2266        let buffer_id = diff.read(cx).buffer_id;
2267
2268        if let Some(existing_diff) = self.diff_for(buffer_id)
2269            && diff.entity_id() == existing_diff.entity_id()
2270        {
2271            return;
2272        }
2273
2274        self.buffer_diff_changed(
2275            diff.clone(),
2276            text::Anchor::min_max_range_for_buffer(buffer_id),
2277            cx,
2278        );
2279        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2280    }
2281
2282    pub fn add_inverted_diff(
2283        &mut self,
2284        diff: Entity<BufferDiff>,
2285        main_buffer: Entity<language::Buffer>,
2286        cx: &mut Context<Self>,
2287    ) {
2288        let snapshot = diff.read(cx).base_text(cx);
2289        let base_text_buffer_id = snapshot.remote_id();
2290        let diff_change_range = 0..snapshot.len();
2291        self.snapshot.get_mut().has_inverted_diff = true;
2292        self.inverted_buffer_diff_changed(
2293            diff.clone(),
2294            main_buffer.clone(),
2295            Some(diff_change_range),
2296            cx,
2297        );
2298        self.diffs.insert(
2299            base_text_buffer_id,
2300            DiffState::new_inverted(diff, main_buffer, cx),
2301        );
2302    }
2303
2304    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2305        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2306    }
2307
2308    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2309        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2310    }
2311
2312    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2313        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2314    }
2315
2316    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2317        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2318        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2319    }
2320
2321    pub fn all_diff_hunks_expanded(&self) -> bool {
2322        self.snapshot.borrow().all_diff_hunks_expanded
2323    }
2324
2325    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2326        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2327        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2328    }
2329
2330    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2331        self.snapshot.get_mut().show_deleted_hunks = show;
2332
2333        self.sync_mut(cx);
2334
2335        let old_len = self.snapshot.borrow().len();
2336
2337        let ranges = std::iter::once((Point::zero()..Point::MAX, Anchor::Max));
2338        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2339
2340        let new_len = self.snapshot.borrow().len();
2341
2342        self.subscriptions.publish(vec![Edit {
2343            old: MultiBufferOffset(0)..old_len,
2344            new: MultiBufferOffset(0)..new_len,
2345        }]);
2346
2347        cx.emit(Event::DiffHunksToggled);
2348        cx.emit(Event::Edited {
2349            edited_buffer: None,
2350        });
2351    }
2352
2353    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2354        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2355    }
2356
2357    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2358        self.read(cx)
2359            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2360            .nth(1)
2361            .is_some()
2362    }
2363
2364    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2365        let snapshot = self.read(cx);
2366        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2367        let offset_range = range.to_offset(&snapshot);
2368        cursor.seek(&offset_range.start, Bias::Left);
2369        while let Some(item) = cursor.item() {
2370            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2371                break;
2372            }
2373            if item.hunk_info().is_some() {
2374                return true;
2375            }
2376            cursor.next();
2377        }
2378        false
2379    }
2380
2381    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2382        let snapshot = self.read(cx);
2383        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2384        for range in ranges {
2385            let range = range.to_point(&snapshot);
2386            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2387            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2388                .min(snapshot.len());
2389            cursor.seek(&start, Bias::Right);
2390            while let Some(item) = cursor.item() {
2391                if *cursor.start() >= end {
2392                    break;
2393                }
2394                if item.hunk_info().is_some() {
2395                    return true;
2396                }
2397                cursor.next();
2398            }
2399        }
2400        false
2401    }
2402
2403    pub fn expand_or_collapse_diff_hunks_inner(
2404        &mut self,
2405        // second element is the end of the last excerpt that should be considered for this range
2406        // (or Anchor::Max to opt out)
2407        ranges: impl IntoIterator<Item = (Range<Point>, Anchor)>,
2408        expand: bool,
2409        cx: &mut Context<Self>,
2410    ) -> Vec<Edit<MultiBufferOffset>> {
2411        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2412            return Vec::new();
2413        }
2414        self.sync_mut(cx);
2415        let mut snapshot = self.snapshot.get_mut();
2416        let mut excerpt_edits = Vec::new();
2417        let mut last_hunk_row = None;
2418        for (range, excerpt_end) in ranges {
2419            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2420                if diff_hunk
2421                    .multi_buffer_range()
2422                    .start
2423                    .cmp(&excerpt_end, &snapshot)
2424                    .is_gt()
2425                {
2426                    dbg!("NOT EXPANDING", diff_hunk.multi_buffer_range(), excerpt_end);
2427                    dbg!(
2428                        diff_hunk.multi_buffer_range().end.to_point(&snapshot),
2429                        excerpt_end.to_point(&snapshot)
2430                    );
2431                    continue;
2432                }
2433                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2434                    dbg!("OTHER CONTINUE");
2435                    continue;
2436                }
2437                let range = diff_hunk.multi_buffer_range();
2438                let start = snapshot.excerpt_offset_for_anchor(&range.start);
2439                let end = snapshot.excerpt_offset_for_anchor(&range.end);
2440                last_hunk_row = Some(diff_hunk.row_range.start);
2441                excerpt_edits.push(text::Edit {
2442                    old: start..end,
2443                    new: start..end,
2444                });
2445            }
2446        }
2447
2448        Self::sync_diff_transforms(
2449            &mut snapshot,
2450            excerpt_edits,
2451            DiffChangeKind::ExpandOrCollapseHunks { expand },
2452        )
2453    }
2454
2455    pub fn expand_or_collapse_diff_hunks(
2456        &mut self,
2457        ranges: Vec<Range<Anchor>>,
2458        expand: bool,
2459        cx: &mut Context<Self>,
2460    ) {
2461        let snapshot = self.snapshot.borrow().clone();
2462        let ranges = ranges.iter().map(move |range| {
2463            let excerpt_end = snapshot
2464                .excerpt_containing(range.end..range.end)
2465                .map(|excerpt| excerpt.end_anchor().into())
2466                .unwrap_or(Anchor::Max);
2467            let range = range.to_point(&snapshot);
2468            let mut peek_end = range.end;
2469            if range.end.row < snapshot.max_row().0 {
2470                peek_end = Point::new(range.end.row + 1, 0);
2471            };
2472            (range.start..peek_end, excerpt_end)
2473        });
2474        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2475        if !edits.is_empty() {
2476            self.subscriptions.publish(edits);
2477        }
2478        cx.emit(Event::DiffHunksToggled);
2479        cx.emit(Event::Edited {
2480            edited_buffer: None,
2481        });
2482    }
2483
2484    #[ztracing::instrument(skip_all)]
2485    fn sync(&self, cx: &App) {
2486        let changed = self.buffer_changed_since_sync.replace(false);
2487        if !changed {
2488            return;
2489        }
2490        let edits = Self::sync_from_buffer_changes(
2491            &mut self.snapshot.borrow_mut(),
2492            &self.buffers,
2493            &self.diffs,
2494            cx,
2495        );
2496        if !edits.is_empty() {
2497            self.subscriptions.publish(edits);
2498        }
2499    }
2500
2501    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2502        let snapshot = self.snapshot.get_mut();
2503        let changed = self.buffer_changed_since_sync.replace(false);
2504        if !changed {
2505            return snapshot;
2506        }
2507        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2508
2509        if !edits.is_empty() {
2510            self.subscriptions.publish(edits);
2511        }
2512
2513        snapshot
2514    }
2515
2516    fn sync_from_buffer_changes(
2517        snapshot: &mut MultiBufferSnapshot,
2518        buffers: &BTreeMap<BufferId, BufferState>,
2519        diffs: &HashMap<BufferId, DiffState>,
2520        cx: &App,
2521    ) -> Vec<Edit<MultiBufferOffset>> {
2522        let MultiBufferSnapshot {
2523            excerpts,
2524            diffs: buffer_diff,
2525            buffers: buffer_snapshots,
2526            path_keys_by_index: _,
2527            diff_transforms: _,
2528            non_text_state_update_count,
2529            edit_count,
2530            is_dirty,
2531            has_deleted_file,
2532            has_conflict,
2533            has_inverted_diff: _,
2534            singleton: _,
2535            trailing_excerpt_update_count: _,
2536            all_diff_hunks_expanded: _,
2537            show_deleted_hunks: _,
2538            use_extended_diff_range: _,
2539            show_headers: _,
2540        } = snapshot;
2541        *is_dirty = false;
2542        *has_deleted_file = false;
2543        *has_conflict = false;
2544
2545        if !diffs.is_empty() {
2546            let mut diffs_to_add = Vec::new();
2547            for (id, diff) in diffs {
2548                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2549                // and use the diff hunk base text ranges to compute diff transforms.
2550                // Those base text ranges are usize, so make sure if the base text changed
2551                // we also update the diff snapshot so that we don't use stale offsets
2552                if buffer_diff.get(id).is_none_or(|existing_diff| {
2553                    if existing_diff.main_buffer.is_none() {
2554                        return false;
2555                    }
2556                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2557                    base_text.remote_id() != existing_diff.base_text().remote_id()
2558                        || base_text
2559                            .version()
2560                            .changed_since(existing_diff.base_text().version())
2561                }) {
2562                    if diffs_to_add.capacity() == 0 {
2563                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2564                        // meaning re-allocations will be fairly expensive
2565                        diffs_to_add.reserve(diffs.len());
2566                    }
2567                    diffs_to_add.push((*id, diff.snapshot(cx)));
2568                }
2569            }
2570            buffer_diff.extend(diffs_to_add);
2571        }
2572
2573        let mut paths_to_edit = Vec::new();
2574        let mut non_text_state_updated = false;
2575        let mut edited = false;
2576        for buffer_state in buffers.values() {
2577            let buffer = buffer_state.buffer.read(cx);
2578            let last_snapshot = buffer_snapshots
2579                .get(&buffer.remote_id())
2580                .expect("each buffer should have a snapshot");
2581            let current_version = buffer.version();
2582            let non_text_state_update_count = buffer.non_text_state_update_count();
2583
2584            let buffer_edited =
2585                current_version.changed_since(last_snapshot.buffer_snapshot.version());
2586            let buffer_non_text_state_updated = non_text_state_update_count
2587                > last_snapshot.buffer_snapshot.non_text_state_update_count();
2588            if buffer_edited || buffer_non_text_state_updated {
2589                paths_to_edit.push((
2590                    last_snapshot.path_key.clone(),
2591                    buffer_state.buffer.clone(),
2592                    if buffer_edited {
2593                        Some(last_snapshot.buffer_snapshot.version().clone())
2594                    } else {
2595                        None
2596                    },
2597                ));
2598            }
2599
2600            edited |= buffer_edited;
2601            non_text_state_updated |= buffer_non_text_state_updated;
2602            *is_dirty |= buffer.is_dirty();
2603            *has_deleted_file |= buffer
2604                .file()
2605                .is_some_and(|file| file.disk_state().is_deleted());
2606            *has_conflict |= buffer.has_conflict();
2607        }
2608        if edited {
2609            *edit_count += 1;
2610        }
2611        if non_text_state_updated {
2612            *non_text_state_update_count += 1;
2613        }
2614
2615        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path.clone());
2616
2617        let mut edits = Vec::new();
2618        let mut new_excerpts = SumTree::default();
2619        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2620
2621        for (path, buffer, prev_version) in paths_to_edit {
2622            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2623            let buffer = buffer.read(cx);
2624            let buffer_id = buffer.remote_id();
2625
2626            buffer_snapshots.insert(
2627                buffer_id,
2628                BufferStateSnapshot {
2629                    path_key: path.clone(),
2630                    buffer_snapshot: buffer.snapshot(),
2631                },
2632            );
2633
2634            if let Some(prev_version) = &prev_version {
2635                while let Some(old_excerpt) = cursor.item()
2636                    && &old_excerpt.path_key == &path
2637                {
2638                    edits.extend(
2639                        buffer
2640                            .edits_since_in_range::<usize>(
2641                                prev_version,
2642                                old_excerpt.range.context.clone(),
2643                            )
2644                            .map(|edit| {
2645                                let excerpt_old_start = cursor.start().len();
2646                                let excerpt_new_start =
2647                                    ExcerptDimension(new_excerpts.summary().text.len);
2648                                let old_start = excerpt_old_start + edit.old.start;
2649                                let old_end = excerpt_old_start + edit.old.end;
2650                                let new_start = excerpt_new_start + edit.new.start;
2651                                let new_end = excerpt_new_start + edit.new.end;
2652                                Edit {
2653                                    old: old_start..old_end,
2654                                    new: new_start..new_end,
2655                                }
2656                            }),
2657                    );
2658
2659                    let excerpt = Excerpt::new(
2660                        old_excerpt.path_key.clone(),
2661                        old_excerpt.path_key_index,
2662                        &buffer.snapshot(),
2663                        old_excerpt.range.clone(),
2664                        old_excerpt.has_trailing_newline,
2665                    );
2666                    new_excerpts.push(excerpt, ());
2667                    cursor.next();
2668                }
2669            } else {
2670                new_excerpts.append(cursor.slice(&path, Bias::Right), ());
2671            };
2672        }
2673        new_excerpts.append(cursor.suffix(), ());
2674
2675        drop(cursor);
2676        *excerpts = new_excerpts;
2677
2678        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2679    }
2680
2681    fn sync_diff_transforms(
2682        snapshot: &mut MultiBufferSnapshot,
2683        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2684        change_kind: DiffChangeKind,
2685    ) -> Vec<Edit<MultiBufferOffset>> {
2686        if excerpt_edits.is_empty() {
2687            return vec![];
2688        }
2689
2690        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2691        let mut old_diff_transforms = snapshot
2692            .diff_transforms
2693            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2694        let mut new_diff_transforms = SumTree::default();
2695        let mut old_expanded_hunks = HashSet::default();
2696        let mut output_edits = Vec::new();
2697        let mut output_delta = 0_isize;
2698        let mut at_transform_boundary = true;
2699        let mut end_of_current_insert = None;
2700
2701        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2702        while let Some(edit) = excerpt_edits.next() {
2703            excerpts.seek_forward(&edit.new.start, Bias::Right);
2704            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2705                excerpts.prev();
2706            }
2707
2708            // Keep any transforms that are before the edit.
2709            if at_transform_boundary {
2710                at_transform_boundary = false;
2711                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2712                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2713                if let Some(transform) = old_diff_transforms.item()
2714                    && old_diff_transforms.end().0 == edit.old.start
2715                    && old_diff_transforms.start().0 < edit.old.start
2716                {
2717                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2718                    old_diff_transforms.next();
2719                }
2720            }
2721
2722            // Compute the start of the edit in output coordinates.
2723            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2724            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2725            let edit_new_start =
2726                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2727
2728            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2729                &edit,
2730                &mut excerpts,
2731                &mut old_diff_transforms,
2732                &mut new_diff_transforms,
2733                &mut end_of_current_insert,
2734                &mut old_expanded_hunks,
2735                snapshot,
2736                change_kind,
2737            );
2738
2739            // Compute the end of the edit in output coordinates.
2740            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2741            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2742            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2743            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2744            let output_edit = Edit {
2745                old: edit_old_start..edit_old_end,
2746                new: edit_new_start..edit_new_end,
2747            };
2748
2749            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2750            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2751            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2752                output_edits.push(output_edit);
2753            }
2754
2755            // If this is the last edit that intersects the current diff transform,
2756            // then recreate the content up to the end of this transform, to prepare
2757            // for reusing additional slices of the old transforms.
2758            if excerpt_edits
2759                .peek()
2760                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2761            {
2762                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2763                    && match old_diff_transforms.item() {
2764                        Some(DiffTransform::BufferContent {
2765                            inserted_hunk_info: Some(hunk),
2766                            ..
2767                        }) => excerpts.item().is_some_and(|excerpt| {
2768                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2769                                && diff.main_buffer.is_some()
2770                            {
2771                                return true;
2772                            }
2773                            hunk.hunk_start_anchor
2774                                .is_valid(&excerpt.buffer_snapshot(&snapshot))
2775                        }),
2776                        _ => true,
2777                    };
2778
2779                let mut excerpt_offset = edit.new.end;
2780                if !keep_next_old_transform {
2781                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2782                    old_diff_transforms.next();
2783                }
2784
2785                old_expanded_hunks.clear();
2786                Self::push_buffer_content_transform(
2787                    snapshot,
2788                    &mut new_diff_transforms,
2789                    excerpt_offset,
2790                    end_of_current_insert,
2791                );
2792                at_transform_boundary = true;
2793            }
2794        }
2795
2796        // Keep any transforms that are after the last edit.
2797        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2798
2799        // Ensure there's always at least one buffer content transform.
2800        if new_diff_transforms.is_empty() {
2801            new_diff_transforms.push(
2802                DiffTransform::BufferContent {
2803                    summary: Default::default(),
2804                    inserted_hunk_info: None,
2805                },
2806                (),
2807            );
2808        }
2809
2810        drop(old_diff_transforms);
2811        drop(excerpts);
2812        snapshot.diff_transforms = new_diff_transforms;
2813        snapshot.edit_count += 1;
2814
2815        #[cfg(any(test, feature = "test-support"))]
2816        snapshot.check_invariants();
2817        output_edits
2818    }
2819
2820    fn recompute_diff_transforms_for_edit(
2821        edit: &Edit<ExcerptOffset>,
2822        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2823        old_diff_transforms: &mut Cursor<
2824            DiffTransform,
2825            Dimensions<ExcerptOffset, MultiBufferOffset>,
2826        >,
2827        new_diff_transforms: &mut SumTree<DiffTransform>,
2828        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2829        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2830        snapshot: &MultiBufferSnapshot,
2831        change_kind: DiffChangeKind,
2832    ) -> bool {
2833        log::trace!(
2834            "recomputing diff transform for edit {:?} => {:?}",
2835            edit.old.start..edit.old.end,
2836            edit.new.start..edit.new.end
2837        );
2838
2839        // Record which hunks were previously expanded.
2840        while let Some(item) = old_diff_transforms.item() {
2841            if let Some(hunk_info) = item.hunk_info() {
2842                log::trace!(
2843                    "previously expanded hunk at {:?}",
2844                    old_diff_transforms.start()
2845                );
2846                old_expanded_hunks.insert(hunk_info);
2847            }
2848            if old_diff_transforms.end().0 > edit.old.end {
2849                break;
2850            }
2851            old_diff_transforms.next();
2852        }
2853
2854        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
2855        // For inverted diffs, hunks are always shown, so we can't skip this.
2856        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
2857        if old_expanded_hunks.is_empty()
2858            && change_kind == DiffChangeKind::BufferEdited
2859            && !all_diff_hunks_expanded
2860            && !snapshot.has_inverted_diff
2861        {
2862            return false;
2863        }
2864
2865        // Visit each excerpt that intersects the edit.
2866        let mut did_expand_hunks = false;
2867        while let Some(excerpt) = excerpts.item() {
2868            // Recompute the expanded hunks in the portion of the excerpt that
2869            // intersects the edit.
2870            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
2871                let buffer_snapshot = &excerpt.buffer_snapshot(&snapshot);
2872                let excerpt_start = *excerpts.start();
2873                let excerpt_end = excerpt_start + excerpt.text_summary.len;
2874                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer_snapshot);
2875                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2876                let edit_buffer_start =
2877                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
2878                let edit_buffer_end =
2879                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
2880                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
2881
2882                if let Some(main_buffer) = &diff.main_buffer {
2883                    for hunk in diff.hunks_intersecting_base_text_range(
2884                        edit_buffer_start..edit_buffer_end,
2885                        main_buffer,
2886                    ) {
2887                        did_expand_hunks = true;
2888                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
2889                        if hunk_buffer_range.start < excerpt_buffer_start {
2890                            log::trace!("skipping hunk that starts before excerpt");
2891                            continue;
2892                        }
2893                        hunk_buffer_range
2894                            .end
2895                            .to_point(&excerpt.buffer_snapshot(&snapshot));
2896                        let hunk_excerpt_start = excerpt_start
2897                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2898                        let hunk_excerpt_end = excerpt_end
2899                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2900                        Self::push_buffer_content_transform(
2901                            snapshot,
2902                            new_diff_transforms,
2903                            hunk_excerpt_start,
2904                            *end_of_current_insert,
2905                        );
2906                        if !hunk_buffer_range.is_empty() {
2907                            let hunk_info = DiffTransformHunkInfo {
2908                                buffer_id: buffer_snapshot.remote_id(),
2909                                hunk_start_anchor: hunk.buffer_range.start,
2910                                hunk_secondary_status: hunk.secondary_status,
2911                                excerpt_end: excerpt.end_anchor(),
2912                                is_logically_deleted: true,
2913                            };
2914                            *end_of_current_insert =
2915                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
2916                        }
2917                    }
2918                } else {
2919                    let edit_anchor_range = buffer_snapshot.anchor_before(edit_buffer_start)
2920                        ..buffer_snapshot.anchor_after(edit_buffer_end);
2921                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer_snapshot) {
2922                        if hunk.is_created_file() && !all_diff_hunks_expanded {
2923                            continue;
2924                        }
2925
2926                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer_snapshot);
2927                        if hunk_buffer_range.start < excerpt_buffer_start {
2928                            log::trace!("skipping hunk that starts before excerpt");
2929                            continue;
2930                        }
2931
2932                        let hunk_info = DiffTransformHunkInfo {
2933                            buffer_id: buffer_snapshot.remote_id(),
2934                            hunk_start_anchor: hunk.buffer_range.start,
2935                            hunk_secondary_status: hunk.secondary_status,
2936                            excerpt_end: excerpt.end_anchor(),
2937                            is_logically_deleted: false,
2938                        };
2939
2940                        let hunk_excerpt_start = excerpt_start
2941                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
2942                        let hunk_excerpt_end = excerpt_end
2943                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
2944
2945                        Self::push_buffer_content_transform(
2946                            snapshot,
2947                            new_diff_transforms,
2948                            hunk_excerpt_start,
2949                            *end_of_current_insert,
2950                        );
2951
2952                        // For every existing hunk, determine if it was previously expanded
2953                        // and if it should currently be expanded.
2954                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
2955                        let should_expand_hunk = match &change_kind {
2956                            DiffChangeKind::DiffUpdated { base_changed: true } => {
2957                                was_previously_expanded || all_diff_hunks_expanded
2958                            }
2959                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
2960                                let intersects = hunk_buffer_range.is_empty()
2961                                    || hunk_buffer_range.end > edit_buffer_start;
2962                                if *expand {
2963                                    intersects || was_previously_expanded || all_diff_hunks_expanded
2964                                } else {
2965                                    !intersects
2966                                        && (was_previously_expanded || all_diff_hunks_expanded)
2967                                }
2968                            }
2969                            _ => was_previously_expanded || all_diff_hunks_expanded,
2970                        };
2971
2972                        if should_expand_hunk {
2973                            did_expand_hunks = true;
2974                            log::trace!(
2975                                "expanding hunk {:?}",
2976                                hunk_excerpt_start..hunk_excerpt_end,
2977                            );
2978
2979                            if !hunk.diff_base_byte_range.is_empty()
2980                                && hunk_buffer_range.start >= edit_buffer_start
2981                                && hunk_buffer_range.start <= excerpt_buffer_end
2982                                && snapshot.show_deleted_hunks
2983                            {
2984                                let base_text = diff.base_text();
2985                                let mut text_cursor =
2986                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
2987                                let mut base_text_summary = text_cursor
2988                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
2989
2990                                let mut has_trailing_newline = false;
2991                                if base_text_summary.last_line_chars > 0 {
2992                                    base_text_summary += TextSummary::newline();
2993                                    has_trailing_newline = true;
2994                                }
2995
2996                                new_diff_transforms.push(
2997                                    DiffTransform::DeletedHunk {
2998                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
2999                                        summary: base_text_summary,
3000                                        buffer_id: buffer_snapshot.remote_id(),
3001                                        hunk_info,
3002                                        has_trailing_newline,
3003                                    },
3004                                    (),
3005                                );
3006                            }
3007
3008                            if !hunk_buffer_range.is_empty() {
3009                                *end_of_current_insert =
3010                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3011                            }
3012                        }
3013                    }
3014                }
3015            }
3016
3017            if excerpts.end() <= edit.new.end {
3018                excerpts.next();
3019            } else {
3020                break;
3021            }
3022        }
3023
3024        did_expand_hunks || !old_expanded_hunks.is_empty()
3025    }
3026
3027    fn append_diff_transforms(
3028        new_transforms: &mut SumTree<DiffTransform>,
3029        subtree: SumTree<DiffTransform>,
3030    ) {
3031        if let Some(DiffTransform::BufferContent {
3032            inserted_hunk_info,
3033            summary,
3034        }) = subtree.first()
3035            && Self::extend_last_buffer_content_transform(
3036                new_transforms,
3037                *inserted_hunk_info,
3038                *summary,
3039            )
3040        {
3041            let mut cursor = subtree.cursor::<()>(());
3042            cursor.next();
3043            cursor.next();
3044            new_transforms.append(cursor.suffix(), ());
3045            return;
3046        }
3047        new_transforms.append(subtree, ());
3048    }
3049
3050    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3051        if let DiffTransform::BufferContent {
3052            inserted_hunk_info: inserted_hunk_anchor,
3053            summary,
3054        } = transform
3055            && Self::extend_last_buffer_content_transform(
3056                new_transforms,
3057                inserted_hunk_anchor,
3058                summary,
3059            )
3060        {
3061            return;
3062        }
3063        new_transforms.push(transform, ());
3064    }
3065
3066    fn push_buffer_content_transform(
3067        old_snapshot: &MultiBufferSnapshot,
3068        new_transforms: &mut SumTree<DiffTransform>,
3069        end_offset: ExcerptOffset,
3070        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3071    ) {
3072        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3073            (end_offset.min(insertion_end_offset), Some(hunk_info))
3074        });
3075        let unchanged_region = [(end_offset, None)];
3076
3077        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3078        {
3079            let start_offset = new_transforms.summary().excerpt_len();
3080            if end_offset <= start_offset {
3081                continue;
3082            }
3083            let summary_to_add = old_snapshot
3084                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3085
3086            if !Self::extend_last_buffer_content_transform(
3087                new_transforms,
3088                inserted_hunk_info,
3089                summary_to_add,
3090            ) {
3091                new_transforms.push(
3092                    DiffTransform::BufferContent {
3093                        summary: summary_to_add,
3094                        inserted_hunk_info,
3095                    },
3096                    (),
3097                )
3098            }
3099        }
3100    }
3101
3102    fn extend_last_buffer_content_transform(
3103        new_transforms: &mut SumTree<DiffTransform>,
3104        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3105        summary_to_add: MBTextSummary,
3106    ) -> bool {
3107        let mut did_extend = false;
3108        new_transforms.update_last(
3109            |last_transform| {
3110                if let DiffTransform::BufferContent {
3111                    summary,
3112                    inserted_hunk_info: inserted_hunk_anchor,
3113                } = last_transform
3114                    && *inserted_hunk_anchor == new_inserted_hunk_info
3115                {
3116                    *summary += summary_to_add;
3117                    did_extend = true;
3118                }
3119            },
3120            (),
3121        );
3122        did_extend
3123    }
3124
3125    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3126        let snapshot = self.snapshot(cx);
3127        let excerpt_end = snapshot
3128            .excerpt_containing(range.end..range.end)
3129            .map(|excerpt| excerpt.end_anchor().into())
3130            .unwrap_or(Anchor::Max);
3131        let point_range = range.to_point(&snapshot);
3132        let expand = !self.single_hunk_is_expanded(range, cx);
3133        let edits =
3134            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_end)], expand, cx);
3135        if !edits.is_empty() {
3136            self.subscriptions.publish(edits);
3137        }
3138        cx.emit(Event::DiffHunksToggled);
3139        cx.emit(Event::Edited {
3140            edited_buffer: None,
3141        });
3142    }
3143}
3144
3145fn build_excerpt_ranges(
3146    ranges: impl IntoIterator<Item = Range<Point>>,
3147    context_line_count: u32,
3148    buffer_snapshot: &BufferSnapshot,
3149) -> Vec<ExcerptRange<Point>> {
3150    ranges
3151        .into_iter()
3152        .map(|range| {
3153            let start_row = range.start.row.saturating_sub(context_line_count);
3154            let start = Point::new(start_row, 0);
3155            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3156            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3157            ExcerptRange {
3158                context: start..end,
3159                primary: range,
3160            }
3161        })
3162        .collect()
3163}
3164
3165#[cfg(any(test, feature = "test-support"))]
3166impl MultiBuffer {
3167    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3168        let buffer = cx.new(|cx| Buffer::local(text, cx));
3169        cx.new(|cx| Self::singleton(buffer, cx))
3170    }
3171
3172    pub fn build_multi<const COUNT: usize>(
3173        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3174        cx: &mut gpui::App,
3175    ) -> Entity<Self> {
3176        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3177        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3178            let buffer = cx.new(|cx| Buffer::local(text, cx));
3179            let snapshot = buffer.read(cx).snapshot();
3180            let excerpt_ranges = ranges
3181                .into_iter()
3182                .map(ExcerptRange::new)
3183                .collect::<Vec<_>>();
3184            multi.update(cx, |multi, cx| {
3185                multi.set_excerpt_ranges_for_path(
3186                    PathKey::sorted(ix as u64),
3187                    buffer,
3188                    &snapshot,
3189                    excerpt_ranges,
3190                    cx,
3191                )
3192            });
3193        }
3194
3195        multi
3196    }
3197
3198    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3199        cx.new(|cx| Self::singleton(buffer, cx))
3200    }
3201
3202    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3203        cx.new(|cx| {
3204            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3205            let mutation_count = rng.random_range(1..=5);
3206            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3207            multibuffer
3208        })
3209    }
3210
3211    pub fn randomly_edit(
3212        &mut self,
3213        rng: &mut impl rand::Rng,
3214        edit_count: usize,
3215        cx: &mut Context<Self>,
3216    ) {
3217        use util::RandomCharIter;
3218
3219        let snapshot = self.read(cx);
3220        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3221        let mut last_end = None;
3222        for _ in 0..edit_count {
3223            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3224                break;
3225            }
3226
3227            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3228            let end =
3229                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3230            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3231            last_end = Some(end);
3232
3233            let mut range = start..end;
3234            if rng.random_bool(0.2) {
3235                mem::swap(&mut range.start, &mut range.end);
3236            }
3237
3238            let new_text_len = rng.random_range(0..10);
3239            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3240
3241            edits.push((range, new_text.into()));
3242        }
3243        log::info!("mutating multi-buffer with {:?}", edits);
3244        drop(snapshot);
3245
3246        self.edit(edits, None, cx);
3247    }
3248
3249    pub fn randomly_edit_excerpts(
3250        &mut self,
3251        rng: &mut impl rand::Rng,
3252        mutation_count: usize,
3253        cx: &mut Context<Self>,
3254    ) {
3255        use rand::prelude::*;
3256        use std::env;
3257        use util::RandomCharIter;
3258
3259        let max_buffers = env::var("MAX_BUFFERS")
3260            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3261            .unwrap_or(5);
3262
3263        let mut buffers = Vec::new();
3264        for _ in 0..mutation_count {
3265            let buffer_ids = self.all_buffer_ids();
3266            if buffer_ids.is_empty() || (rng.random() && buffer_ids.len() < max_buffers) {
3267                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3268                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3269                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3270                    let buffer = buffers.last().unwrap().read(cx);
3271                    log::info!(
3272                        "Creating new buffer {} with text: {:?}",
3273                        buffer.remote_id(),
3274                        buffer.text()
3275                    );
3276                    buffers.last().unwrap().clone()
3277                } else {
3278                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3279                };
3280
3281                let buffer = buffer_handle.read(cx);
3282                let buffer_text = buffer.text();
3283                let buffer_snapshot = buffer.snapshot();
3284                let mut next_min_start_ix = 0;
3285                let ranges = (0..rng.random_range(0..5))
3286                    .filter_map(|_| {
3287                        if next_min_start_ix == buffer.len() {
3288                            return None;
3289                        }
3290                        let end_ix = buffer.clip_offset(
3291                            rng.random_range(next_min_start_ix..=buffer.len()),
3292                            Bias::Right,
3293                        );
3294                        let start_ix = buffer
3295                            .clip_offset(rng.random_range(next_min_start_ix..=end_ix), Bias::Left);
3296                        next_min_start_ix = end_ix;
3297                        Some(ExcerptRange::new(start_ix..end_ix))
3298                    })
3299                    .collect::<Vec<_>>();
3300                // todo!() mutate excerpts more realistically?
3301                log::info!(
3302                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3303                    buffer_handle.read(cx).remote_id(),
3304                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3305                    ranges
3306                        .iter()
3307                        .map(|r| &buffer_text[r.context.clone()])
3308                        .collect::<Vec<_>>()
3309                );
3310
3311                let path_key = PathKey::sorted(rng.random_range(0..max_buffers * 3) as u64);
3312                self.set_merged_excerpt_ranges_for_path(
3313                    path_key.clone(),
3314                    buffer_handle,
3315                    &buffer_snapshot,
3316                    ranges,
3317                    cx,
3318                );
3319                log::info!("Inserted with path_key: {:?}", path_key);
3320            } else {
3321                let path_key = self
3322                    .snapshot
3323                    .borrow()
3324                    .buffers
3325                    .get(&buffer_ids.choose(rng).unwrap())
3326                    .unwrap()
3327                    .path_key
3328                    .clone();
3329                log::info!("Removing excerpts {:?}", path_key);
3330                self.remove_excerpts(path_key, cx);
3331            }
3332        }
3333    }
3334
3335    pub fn randomly_mutate(
3336        &mut self,
3337        rng: &mut impl rand::Rng,
3338        mutation_count: usize,
3339        cx: &mut Context<Self>,
3340    ) {
3341        use rand::prelude::*;
3342
3343        if rng.random_bool(0.7) || self.singleton {
3344            let buffer = self
3345                .buffers
3346                .values()
3347                .choose(rng)
3348                .map(|state| state.buffer.clone());
3349
3350            if let Some(buffer) = buffer {
3351                buffer.update(cx, |buffer, cx| {
3352                    if rng.random() {
3353                        buffer.randomly_edit(rng, mutation_count, cx);
3354                    } else {
3355                        buffer.randomly_undo_redo(rng, cx);
3356                    }
3357                });
3358            } else {
3359                self.randomly_edit(rng, mutation_count, cx);
3360            }
3361        } else {
3362            self.randomly_edit_excerpts(rng, mutation_count, cx);
3363        }
3364
3365        self.check_invariants(cx);
3366    }
3367
3368    fn check_invariants(&self, cx: &App) {
3369        self.read(cx).check_invariants();
3370    }
3371}
3372
3373impl EventEmitter<Event> for MultiBuffer {}
3374
3375impl MultiBufferSnapshot {
3376    pub fn text(&self) -> String {
3377        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3378            .map(|chunk| chunk.text)
3379            .collect()
3380    }
3381
3382    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3383        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3384            .flat_map(|c| c.chars().rev())
3385    }
3386
3387    fn reversed_chunks_in_range(
3388        &self,
3389        range: Range<MultiBufferOffset>,
3390    ) -> ReversedMultiBufferChunks<'_> {
3391        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3392        cursor.seek(&range.end);
3393        let current_chunks = cursor.region().as_ref().map(|region| {
3394            let start_overshoot = range.start.saturating_sub(region.range.start);
3395            let end_overshoot = range.end - region.range.start;
3396            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3397            let start = region.buffer_range.start + start_overshoot;
3398            region.buffer.reversed_chunks_in_range(start..end)
3399        });
3400        ReversedMultiBufferChunks {
3401            cursor,
3402            current_chunks,
3403            start: range.start,
3404            offset: range.end,
3405        }
3406    }
3407
3408    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3409        let offset = position.to_offset(self);
3410        self.text_for_range(offset..self.len())
3411            .flat_map(|chunk| chunk.chars())
3412    }
3413
3414    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3415        self.chunks(range, false).map(|chunk| chunk.text)
3416    }
3417
3418    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3419        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3420            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3421    }
3422
3423    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3424    where
3425        T: ToOffset,
3426    {
3427        let position = position.to_offset(self);
3428        position == self.clip_offset(position, Bias::Left)
3429            && self
3430                .bytes_in_range(position..self.len())
3431                .flatten()
3432                .copied()
3433                .take(needle.len())
3434                .eq(needle.bytes())
3435    }
3436
3437    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3438        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3439    }
3440
3441    pub fn diff_hunks_in_range<T: ToPoint>(
3442        &self,
3443        range: Range<T>,
3444    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3445        let query_range = range.start.to_point(self)..range.end.to_point(self);
3446        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3447            let diff = self.diffs.get(&buffer.remote_id())?;
3448            let iter = if let Some(main_buffer) = &diff.main_buffer {
3449                let buffer_start = buffer.point_to_offset(buffer_range.start);
3450                let buffer_end = buffer.point_to_offset(buffer_range.end);
3451                itertools::Either::Left(
3452                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3453                        .map(move |hunk| (hunk, buffer, true)),
3454                )
3455            } else {
3456                let buffer_start = buffer.anchor_before(buffer_range.start);
3457                let buffer_end = buffer.anchor_after(buffer_range.end);
3458                itertools::Either::Right(
3459                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3460                        .map(move |hunk| (hunk, buffer, false)),
3461                )
3462            };
3463            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3464                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3465                    return None;
3466                }
3467                let range = if is_inverted {
3468                    hunk.diff_base_byte_range.to_point(&buffer)
3469                } else {
3470                    hunk.range.clone()
3471                };
3472                Some((range, (hunk, is_inverted)))
3473            }))
3474        })
3475        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3476            let buffer_snapshot = excerpt.buffer_snapshot(self);
3477            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3478            {
3479                return None;
3480            }
3481            let end_row = if range.end.column == 0 {
3482                range.end.row
3483            } else {
3484                range.end.row + 1
3485            };
3486
3487            let word_diffs =
3488                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3489                    .then(|| {
3490                        let mut word_diffs = Vec::new();
3491
3492                        if self.show_deleted_hunks || is_inverted {
3493                            let hunk_start_offset = if is_inverted {
3494                                Anchor::in_buffer(
3495                                    excerpt.path_key_index,
3496                                    buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start),
3497                                )
3498                                .to_offset(self)
3499                            } else {
3500                                Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3501                                    .to_offset(self)
3502                            };
3503
3504                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3505                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3506                            }));
3507                        }
3508
3509                        if !is_inverted {
3510                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3511                                Anchor::range_in_buffer(excerpt.path_key_index, diff)
3512                                    .to_offset(self)
3513                            }));
3514                        }
3515                        word_diffs
3516                    })
3517                    .unwrap_or_default();
3518
3519            let buffer_range = if is_inverted {
3520                buffer_snapshot.anchor_after(hunk.diff_base_byte_range.start)
3521                    ..buffer_snapshot.anchor_before(hunk.diff_base_byte_range.end)
3522            } else {
3523                hunk.buffer_range.clone()
3524            };
3525            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3526                DiffHunkStatusKind::Deleted
3527            } else if hunk.diff_base_byte_range.is_empty() {
3528                DiffHunkStatusKind::Added
3529            } else {
3530                DiffHunkStatusKind::Modified
3531            };
3532            Some(MultiBufferDiffHunk {
3533                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3534                buffer_id: buffer_snapshot.remote_id(),
3535                path_key_index: excerpt.path_key_index,
3536                buffer_range,
3537                word_diffs,
3538                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3539                    ..BufferOffset(hunk.diff_base_byte_range.end),
3540                status: DiffHunkStatus {
3541                    kind: status_kind,
3542                    secondary: hunk.secondary_status,
3543                },
3544            })
3545        })
3546    }
3547
3548    fn excerpts_for_range<T: ToOffset>(
3549        &self,
3550        range: Range<T>,
3551    ) -> impl Iterator<Item = &Excerpt> + '_ {
3552        let range = range.start.to_offset(self)..range.end.to_offset(self);
3553        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3554        cursor.seek(&range.start);
3555        std::iter::from_fn(move || {
3556            let region = cursor.region()?;
3557            if region.range.start > range.end
3558                || region.range.start == range.end && region.range.start > range.start
3559            {
3560                return None;
3561            }
3562            let excerpt = region.excerpt;
3563            cursor.next_excerpt_forwards();
3564            Some(excerpt)
3565        })
3566    }
3567
3568    // todo!() repeats ids? seems weird
3569    pub fn buffer_ids_for_range<T: ToOffset>(
3570        &self,
3571        range: Range<T>,
3572    ) -> impl Iterator<Item = BufferId> + '_ {
3573        self.excerpts_for_range(range)
3574            .map(|excerpt| excerpt.buffer_snapshot(self).remote_id())
3575    }
3576
3577    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3578    ///
3579    /// The passed in anchors must be ordered.
3580    pub fn text_anchors_to_visible_anchors(
3581        &self,
3582        anchors: impl IntoIterator<Item = text::Anchor>,
3583    ) -> Vec<Option<Anchor>> {
3584        let anchors = anchors.into_iter();
3585        let mut result = Vec::with_capacity(anchors.size_hint().0);
3586        let mut anchors = anchors.peekable();
3587        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3588        'anchors: while let Some(anchor) = anchors.peek() {
3589            let buffer_id = anchor.buffer_id;
3590            let mut same_buffer_anchors = anchors.peeking_take_while(|a| a.buffer_id == buffer_id);
3591
3592            if let Some(buffer) = self.buffers.get(&buffer_id) {
3593                let path = &buffer.path_key;
3594                let Some(mut next) = same_buffer_anchors.next() else {
3595                    continue 'anchors;
3596                };
3597                cursor.seek_forward(path, Bias::Left);
3598                'excerpts: loop {
3599                    let Some(excerpt) = cursor.item() else {
3600                        break;
3601                    };
3602                    if &excerpt.path_key != path {
3603                        break;
3604                    }
3605                    let buffer_snapshot = excerpt.buffer_snapshot(self);
3606
3607                    loop {
3608                        // anchor is before the first excerpt
3609                        if excerpt
3610                            .range
3611                            .context
3612                            .start
3613                            .cmp(&next, &buffer_snapshot)
3614                            .is_gt()
3615                        {
3616                            // so we skip it and try the next anchor
3617                            result.push(None);
3618                            match same_buffer_anchors.next() {
3619                                Some(anchor) => next = anchor,
3620                                None => continue 'anchors,
3621                            }
3622                        // anchor is within the excerpt
3623                        } else if excerpt
3624                            .range
3625                            .context
3626                            .end
3627                            .cmp(&next, &buffer_snapshot)
3628                            .is_ge()
3629                        {
3630                            // record it and all following anchors that are within
3631                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3632                            result.extend(
3633                                same_buffer_anchors
3634                                    .peeking_take_while(|a| {
3635                                        excerpt.range.context.end.cmp(a, &buffer_snapshot).is_ge()
3636                                    })
3637                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3638                            );
3639                            match same_buffer_anchors.next() {
3640                                Some(anchor) => next = anchor,
3641                                None => continue 'anchors,
3642                            }
3643                        // anchor is after the excerpt, try the next one
3644                        } else {
3645                            cursor.next();
3646                            continue 'excerpts;
3647                        }
3648                    }
3649                }
3650                // account for `next`
3651                result.push(None);
3652            }
3653            result.extend(same_buffer_anchors.map(|_| None));
3654        }
3655
3656        result
3657    }
3658
3659    // todo!() can we make this not RangeBounds
3660    pub fn range_to_buffer_ranges<T: ToOffset>(
3661        &self,
3662        range: Range<T>,
3663    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>)> {
3664        self.range_to_buffer_ranges_with_context(range)
3665            .into_iter()
3666            .map(|(buffer, range, _context)| (buffer, range))
3667            .collect()
3668    }
3669
3670    pub fn range_to_buffer_ranges_with_context<T: ToOffset>(
3671        &self,
3672        range: Range<T>,
3673    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)> {
3674        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3675        let start = range.start.to_offset(self);
3676        let end = range.end.to_offset(self);
3677        cursor.seek(&start);
3678
3679        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, Range<text::Anchor>)> =
3680            Vec::new();
3681        while let Some(region) = cursor.region() {
3682            if region.range.start >= end {
3683                break;
3684            }
3685            if region.is_main_buffer {
3686                let start_overshoot = start.saturating_sub(region.range.start);
3687                let end_offset = end;
3688                let end_overshoot = end_offset.saturating_sub(region.range.start);
3689                let start = region
3690                    .buffer_range
3691                    .end
3692                    .min(region.buffer_range.start + start_overshoot);
3693                let end = region
3694                    .buffer_range
3695                    .end
3696                    .min(region.buffer_range.start + end_overshoot);
3697                let context = region.excerpt.range.context.clone();
3698                if let Some(prev) = result.last_mut().filter(|(prev_buffer, prev_range, _)| {
3699                    prev_buffer.remote_id() == region.buffer.remote_id() && prev_range.end == start
3700                }) {
3701                    prev.1.end = end;
3702                } else {
3703                    result.push((region.buffer, start..end, context));
3704                }
3705            }
3706            cursor.next();
3707        }
3708
3709        // Handle empty trailing excerpt, which doesn't have a region
3710        if let Some(excerpt) = cursor.excerpt()
3711            && excerpt.text_summary.len == 0
3712            && end == self.len()
3713        {
3714            let buffer_snapshot = excerpt.buffer_snapshot(self);
3715
3716            let buffer_offset =
3717                BufferOffset(excerpt.range.context.start.to_offset(buffer_snapshot));
3718            let context = excerpt.range.context.clone();
3719            if result
3720                .last_mut()
3721                .is_none_or(|(prev_buffer, prev_range, _)| {
3722                    prev_buffer.remote_id() != excerpt.buffer_id || prev_range.end != buffer_offset
3723                })
3724            {
3725                result.push((buffer_snapshot, buffer_offset..buffer_offset, context));
3726            }
3727        }
3728
3729        result
3730    }
3731
3732    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3733        &self,
3734        range: Range<T>,
3735    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, Option<Anchor>)> + '_ {
3736        let start = range.start.to_offset(self);
3737        let end = range.end.to_offset(self);
3738
3739        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3740        cursor.seek(&start);
3741
3742        std::iter::from_fn(move || {
3743            let region = cursor.region()?;
3744            if region.range.start > end {
3745                return None;
3746            }
3747            let start_overshoot = start.saturating_sub(region.range.start);
3748            let end_overshoot = end.saturating_sub(region.range.start);
3749            let start = region
3750                .buffer_range
3751                .end
3752                .min(region.buffer_range.start + start_overshoot);
3753            let end = region
3754                .buffer_range
3755                .end
3756                .min(region.buffer_range.start + end_overshoot);
3757
3758            let deleted_hunk_anchor = if region.is_main_buffer {
3759                None
3760            } else {
3761                Some(self.anchor_before(region.range.start))
3762            };
3763            let result = (region.buffer, start..end, deleted_hunk_anchor);
3764            cursor.next();
3765            Some(result)
3766        })
3767    }
3768
3769    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3770    /// coordinates.
3771    ///
3772    /// The given callback will be called for every excerpt intersecting the given range. It will
3773    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3774    /// The callback should return an iterator of metadata items from that buffer, each paired
3775    /// with a buffer range.
3776    ///
3777    /// The returned iterator yields each of these metadata items, paired with its range in
3778    /// multi-buffer coordinates.
3779    fn lift_buffer_metadata<'a, MBD, M, I>(
3780        &'a self,
3781        query_range: Range<MBD>,
3782        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3783    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3784    where
3785        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3786        MBD: MultiBufferDimension
3787            + Ord
3788            + Sub<Output = MBD::TextDimension>
3789            + ops::Add<MBD::TextDimension, Output = MBD>
3790            + ops::AddAssign<MBD::TextDimension>,
3791        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3792            + ops::Add<Output = MBD::TextDimension>
3793            + AddAssign<MBD::TextDimension>
3794            + Ord,
3795    {
3796        let mut current_excerpt_metadata: Option<(ExcerptAnchor, I)> = None;
3797        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3798
3799        // Find the excerpt and buffer offset where the given range ends.
3800        cursor.seek(&query_range.end);
3801        let mut range_end = None;
3802        while let Some(region) = cursor.region() {
3803            if region.is_main_buffer {
3804                let mut buffer_end = region.buffer_range.start;
3805                let overshoot = if query_range.end > region.range.start {
3806                    query_range.end - region.range.start
3807                } else {
3808                    <MBD::TextDimension>::default()
3809                };
3810                buffer_end = buffer_end + overshoot;
3811                range_end = Some((region.excerpt.end_anchor(), buffer_end));
3812                break;
3813            }
3814            cursor.next();
3815        }
3816
3817        cursor.seek(&query_range.start);
3818
3819        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3820            && region.range.start > MBD::default()
3821        {
3822            cursor.prev()
3823        } else if let Some(region) = cursor.region()
3824            && region.is_main_buffer
3825            && region.diff_hunk_status.is_some()
3826        {
3827            cursor.prev();
3828            if cursor.region().is_none_or(|region| region.is_main_buffer) {
3829                cursor.next();
3830            }
3831        }
3832
3833        iter::from_fn(move || {
3834            loop {
3835                let excerpt = cursor.excerpt()?;
3836                let buffer_snapshot = excerpt.buffer_snapshot(self);
3837
3838                // If we have already retrieved metadata for this excerpt, continue to use it.
3839                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3840                    .as_mut()
3841                    .filter(|(excerpt_anchor, _)| excerpt_anchor == &excerpt.end_anchor())
3842                {
3843                    Some(metadata)
3844                }
3845                // Otherwise, compute the intersection of the input range with the excerpt's range,
3846                // and retrieve the metadata for the resulting range.
3847                else {
3848                    let region = cursor.region()?;
3849                    let mut buffer_start;
3850                    if region.is_main_buffer {
3851                        buffer_start = region.buffer_range.start;
3852                        if query_range.start > region.range.start {
3853                            let overshoot = query_range.start - region.range.start;
3854                            buffer_start = buffer_start + overshoot;
3855                        }
3856                        buffer_start = buffer_start.min(region.buffer_range.end);
3857                    } else {
3858                        buffer_start = cursor.main_buffer_position()?;
3859                    };
3860                    let mut buffer_end = excerpt
3861                        .range
3862                        .context
3863                        .end
3864                        .summary::<MBD::TextDimension>(&buffer_snapshot);
3865                    if let Some((end_excerpt, end_buffer_offset)) = range_end
3866                        && excerpt.end_anchor() == end_excerpt
3867                    {
3868                        buffer_end = buffer_end.min(end_buffer_offset);
3869                    }
3870
3871                    get_buffer_metadata(&buffer_snapshot, buffer_start..buffer_end).map(
3872                        |iterator| {
3873                            &mut current_excerpt_metadata
3874                                .insert((excerpt.end_anchor(), iterator))
3875                                .1
3876                        },
3877                    )
3878                };
3879
3880                // Visit each metadata item.
3881                if let Some((metadata_buffer_range, metadata)) =
3882                    metadata_iter.and_then(Iterator::next)
3883                {
3884                    // Find the multibuffer regions that contain the start and end of
3885                    // the metadata item's range.
3886                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3887                        while let Some(region) = cursor.region() {
3888                            if (region.is_main_buffer
3889                                && (region.buffer_range.end >= metadata_buffer_range.start
3890                                    || cursor.is_at_end_of_excerpt()))
3891                                || (!region.is_main_buffer
3892                                    && region.buffer_range.start == metadata_buffer_range.start)
3893                            {
3894                                break;
3895                            }
3896                            cursor.next();
3897                        }
3898                    }
3899                    let start_region = cursor.region()?.clone();
3900                    while let Some(region) = cursor.region() {
3901                        if region.is_main_buffer
3902                            && (region.buffer_range.end > metadata_buffer_range.end
3903                                || cursor.is_at_end_of_excerpt())
3904                        {
3905                            break;
3906                        }
3907                        cursor.next();
3908                    }
3909                    let end_region = cursor.region();
3910
3911                    // Convert the metadata item's range into multibuffer coordinates.
3912                    let mut start_position = start_region.range.start;
3913                    let region_buffer_start = start_region.buffer_range.start;
3914                    if start_region.is_main_buffer
3915                        && metadata_buffer_range.start > region_buffer_start
3916                    {
3917                        start_position =
3918                            start_position + (metadata_buffer_range.start - region_buffer_start);
3919                        start_position = start_position.min(start_region.range.end);
3920                    }
3921
3922                    let mut end_position = self.max_position();
3923                    if let Some(end_region) = &end_region {
3924                        end_position = end_region.range.start;
3925                        debug_assert!(end_region.is_main_buffer);
3926                        let region_buffer_start = end_region.buffer_range.start;
3927                        if metadata_buffer_range.end > region_buffer_start {
3928                            end_position =
3929                                end_position + (metadata_buffer_range.end - region_buffer_start);
3930                        }
3931                        end_position = end_position.min(end_region.range.end);
3932                    }
3933
3934                    if start_position <= query_range.end && end_position >= query_range.start {
3935                        return Some((start_position..end_position, metadata, excerpt));
3936                    }
3937                }
3938                // When there are no more metadata items for this excerpt, move to the next excerpt.
3939                else {
3940                    current_excerpt_metadata.take();
3941                    if let Some((end_excerpt, _)) = range_end
3942                        && excerpt.end_anchor() == end_excerpt
3943                    {
3944                        return None;
3945                    }
3946                    cursor.next_excerpt_forwards();
3947                }
3948            }
3949        })
3950    }
3951
3952    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3953        let offset = position.to_offset(self);
3954
3955        let mut cursor = self
3956            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
3957            );
3958        cursor.seek(&DimensionPair {
3959            key: offset,
3960            value: None,
3961        });
3962        cursor.seek_to_start_of_current_excerpt();
3963        let excerpt = cursor.excerpt()?;
3964
3965        let buffer = excerpt.buffer_snapshot(self);
3966        let excerpt_start = excerpt.range.context.start.to_offset(buffer);
3967        let excerpt_end = excerpt.range.context.end.to_offset(buffer);
3968        let current_position = match self.anchor_before(offset) {
3969            Anchor::Min => 0,
3970            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor.text_anchor().to_offset(buffer),
3971            Anchor::Max => unreachable!(),
3972        };
3973
3974        if let Some(diff) = self.diffs.get(&buffer.remote_id()) {
3975            if let Some(main_buffer) = &diff.main_buffer {
3976                for hunk in diff
3977                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
3978                {
3979                    if hunk.diff_base_byte_range.end >= current_position {
3980                        continue;
3981                    }
3982                    let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
3983                    let start =
3984                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
3985                    return Some(MultiBufferRow(start.row));
3986                }
3987            } else {
3988                let excerpt_end = buffer.anchor_before(excerpt_end.min(current_position));
3989                for hunk in diff
3990                    .hunks_intersecting_range_rev(excerpt.range.context.start..excerpt_end, buffer)
3991                {
3992                    let hunk_end = hunk.buffer_range.end.to_offset(buffer);
3993                    if hunk_end >= current_position {
3994                        continue;
3995                    }
3996                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
3997                        .to_point(self);
3998                    return Some(MultiBufferRow(start.row));
3999                }
4000            }
4001        }
4002
4003        loop {
4004            cursor.prev_excerpt();
4005            let excerpt = cursor.excerpt()?;
4006
4007            let buffer = excerpt.buffer_snapshot(self);
4008            let Some(diff) = self.diffs.get(&buffer.remote_id()) else {
4009                continue;
4010            };
4011            if let Some(main_buffer) = &diff.main_buffer {
4012                let Some(hunk) = diff
4013                    .hunks_intersecting_base_text_range_rev(
4014                        excerpt.range.context.to_offset(buffer),
4015                        main_buffer,
4016                    )
4017                    .next()
4018                else {
4019                    continue;
4020                };
4021                let hunk_start = buffer.anchor_after(hunk.diff_base_byte_range.start);
4022                let start = Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4023                return Some(MultiBufferRow(start.row));
4024            } else {
4025                let Some(hunk) = diff
4026                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), buffer)
4027                    .next()
4028                else {
4029                    continue;
4030                };
4031                let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4032                    .to_point(self);
4033                return Some(MultiBufferRow(start.row));
4034            }
4035        }
4036    }
4037
4038    pub fn has_diff_hunks(&self) -> bool {
4039        self.diffs.values().any(|diff| !diff.is_empty())
4040    }
4041
4042    pub fn is_inside_word<T: ToOffset>(
4043        &self,
4044        position: T,
4045        scope_context: Option<CharScopeContext>,
4046    ) -> bool {
4047        let position = position.to_offset(self);
4048        let classifier = self
4049            .char_classifier_at(position)
4050            .scope_context(scope_context);
4051        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4052        let prev_char_kind = self
4053            .reversed_chars_at(position)
4054            .next()
4055            .map(|c| classifier.kind(c));
4056        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4057    }
4058
4059    pub fn surrounding_word<T: ToOffset>(
4060        &self,
4061        start: T,
4062        scope_context: Option<CharScopeContext>,
4063    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4064        let mut start = start.to_offset(self);
4065        let mut end = start;
4066        let mut next_chars = self.chars_at(start).peekable();
4067        let mut prev_chars = self.reversed_chars_at(start).peekable();
4068
4069        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4070
4071        let word_kind = cmp::max(
4072            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4073            next_chars.peek().copied().map(|c| classifier.kind(c)),
4074        );
4075
4076        for ch in prev_chars {
4077            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4078                start -= ch.len_utf8();
4079            } else {
4080                break;
4081            }
4082        }
4083
4084        for ch in next_chars {
4085            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4086                end += ch.len_utf8();
4087            } else {
4088                break;
4089            }
4090        }
4091
4092        (start..end, word_kind)
4093    }
4094
4095    pub fn char_kind_before<T: ToOffset>(
4096        &self,
4097        start: T,
4098        scope_context: Option<CharScopeContext>,
4099    ) -> Option<CharKind> {
4100        let start = start.to_offset(self);
4101        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4102        self.reversed_chars_at(start)
4103            .next()
4104            .map(|ch| classifier.kind(ch))
4105    }
4106
4107    pub fn is_singleton(&self) -> bool {
4108        self.singleton
4109    }
4110
4111    pub fn as_singleton(&self) -> Option<&BufferSnapshot> {
4112        if self.singleton {
4113            self.excerpts.first().map(|e| e.buffer_snapshot(self))
4114        } else {
4115            None
4116        }
4117    }
4118
4119    pub fn len(&self) -> MultiBufferOffset {
4120        self.diff_transforms.summary().output.len
4121    }
4122
4123    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4124        MBD::from_summary(&self.text_summary())
4125    }
4126
4127    pub fn is_empty(&self) -> bool {
4128        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4129    }
4130
4131    pub fn widest_line_number(&self) -> u32 {
4132        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4133        self.excerpts.summary().widest_line_number + 1
4134    }
4135
4136    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4137        let range = range.start.to_offset(self)..range.end.to_offset(self);
4138        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4139        excerpts.seek(&range.start);
4140
4141        let mut chunk;
4142        let mut has_trailing_newline;
4143        let excerpt_bytes;
4144        if let Some(region) = excerpts.region() {
4145            let mut bytes = region.buffer.bytes_in_range(
4146                region.buffer_range.start + (range.start - region.range.start)
4147                    ..(region.buffer_range.start + (range.end - region.range.start))
4148                        .min(region.buffer_range.end),
4149            );
4150            chunk = bytes.next().unwrap_or(&[][..]);
4151            excerpt_bytes = Some(bytes);
4152            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4153            if chunk.is_empty() && has_trailing_newline {
4154                chunk = b"\n";
4155                has_trailing_newline = false;
4156            }
4157        } else {
4158            chunk = &[][..];
4159            excerpt_bytes = None;
4160            has_trailing_newline = false;
4161        };
4162
4163        MultiBufferBytes {
4164            range,
4165            cursor: excerpts,
4166            excerpt_bytes,
4167            has_trailing_newline,
4168            chunk,
4169        }
4170    }
4171
4172    pub fn reversed_bytes_in_range<T: ToOffset>(
4173        &self,
4174        range: Range<T>,
4175    ) -> ReversedMultiBufferBytes<'_> {
4176        let range = range.start.to_offset(self)..range.end.to_offset(self);
4177        let mut chunks = self.reversed_chunks_in_range(range.clone());
4178        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4179        ReversedMultiBufferBytes {
4180            range,
4181            chunks,
4182            chunk,
4183        }
4184    }
4185
4186    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4187        let mut cursor = self.cursor::<Point, Point>();
4188        cursor.seek(&Point::new(start_row.0, 0));
4189        let mut result = MultiBufferRows {
4190            point: Point::new(0, 0),
4191            is_empty: self.excerpts.is_empty(),
4192            is_singleton: self.is_singleton(),
4193            cursor,
4194        };
4195        result.seek(start_row);
4196        result
4197    }
4198
4199    pub fn chunks<T: ToOffset>(
4200        &self,
4201        range: Range<T>,
4202        language_aware: bool,
4203    ) -> MultiBufferChunks<'_> {
4204        let mut chunks = MultiBufferChunks {
4205            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4206                ..ExcerptDimension(MultiBufferOffset::ZERO),
4207            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4208            excerpts: self.excerpts.cursor(()),
4209            diff_transforms: self.diff_transforms.cursor(()),
4210            diff_base_chunks: None,
4211            excerpt_chunks: None,
4212            buffer_chunk: None,
4213            language_aware,
4214            snapshot: self,
4215        };
4216        let range = range.start.to_offset(self)..range.end.to_offset(self);
4217        chunks.seek(range);
4218        chunks
4219    }
4220
4221    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4222        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4223    }
4224
4225    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4226        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4227    }
4228
4229    pub fn clip_offset_utf16(
4230        &self,
4231        offset: MultiBufferOffsetUtf16,
4232        bias: Bias,
4233    ) -> MultiBufferOffsetUtf16 {
4234        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4235    }
4236
4237    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4238        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4239            buffer.clip_point_utf16(Unclipped(point), bias)
4240        })
4241    }
4242
4243    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4244        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4245    }
4246
4247    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4248        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4249    }
4250
4251    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4252        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4253    }
4254
4255    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4256        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4257    }
4258
4259    #[instrument(skip_all)]
4260    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4261        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4262    }
4263
4264    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4265        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4266    }
4267
4268    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4269        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4270    }
4271
4272    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4273        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4274    }
4275
4276    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4277        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4278    }
4279
4280    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4281        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4282    }
4283
4284    fn clip_dimension<MBD, BD>(
4285        &self,
4286        position: MBD,
4287        bias: Bias,
4288        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4289    ) -> MBD
4290    where
4291        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4292        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4293    {
4294        let mut cursor = self.cursor::<MBD, BD>();
4295        cursor.seek(&position);
4296        if let Some(region) = cursor.region() {
4297            if position >= region.range.end {
4298                return region.range.end;
4299            }
4300            let overshoot = position - region.range.start;
4301            let mut buffer_position = region.buffer_range.start;
4302            buffer_position += overshoot;
4303            let clipped_buffer_position =
4304                clip_buffer_position(region.buffer, buffer_position, bias);
4305            let mut position = region.range.start;
4306            position += clipped_buffer_position - region.buffer_range.start;
4307            position
4308        } else {
4309            self.max_position()
4310        }
4311    }
4312
4313    #[instrument(skip_all)]
4314    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4315        &self,
4316        key: MBR1,
4317        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4318    ) -> MBR2
4319    where
4320        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4321        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4322        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4323        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4324    {
4325        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4326        cursor.seek(&DimensionPair { key, value: None });
4327        if let Some(region) = cursor.region() {
4328            if key >= region.range.end.key {
4329                return region.range.end.value.unwrap();
4330            }
4331            let start_key = region.range.start.key;
4332            let start_value = region.range.start.value.unwrap();
4333            let buffer_start_key = region.buffer_range.start.key;
4334            let buffer_start_value = region.buffer_range.start.value.unwrap();
4335            let mut buffer_key = buffer_start_key;
4336            buffer_key += key - start_key;
4337            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4338            let mut result = start_value;
4339            result += buffer_value - buffer_start_value;
4340            result
4341        } else {
4342            self.max_position()
4343        }
4344    }
4345
4346    pub fn point_to_buffer_offset<T: ToOffset>(
4347        &self,
4348        point: T,
4349    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4350        let offset = point.to_offset(self);
4351        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4352        cursor.seek(&offset);
4353        let region = cursor.region()?;
4354        let overshoot = offset - region.range.start;
4355        let buffer_offset = region.buffer_range.start + overshoot;
4356        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4357            && region.has_trailing_newline
4358            && !region.is_main_buffer
4359        {
4360            let main_buffer_position = cursor.main_buffer_position()?;
4361            let buffer_snapshot = cursor.excerpt()?.buffer_snapshot(self);
4362            return Some((buffer_snapshot, main_buffer_position));
4363        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4364            return None;
4365        }
4366        Some((region.buffer, buffer_offset))
4367    }
4368
4369    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4370        let mut cursor = self.cursor::<Point, Point>();
4371        cursor.seek(&point);
4372        let region = cursor.region()?;
4373        let overshoot = point - region.range.start;
4374        let buffer_point = region.buffer_range.start + overshoot;
4375        let excerpt = cursor.excerpt()?;
4376        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4377            && region.has_trailing_newline
4378            && !region.is_main_buffer
4379        {
4380            return Some((
4381                &excerpt.buffer_snapshot(self),
4382                cursor.main_buffer_position()?,
4383            ));
4384        } else if buffer_point > region.buffer.max_point() {
4385            return None;
4386        }
4387        Some((region.buffer, buffer_point))
4388    }
4389
4390    pub fn suggested_indents(
4391        &self,
4392        rows: impl IntoIterator<Item = u32>,
4393        cx: &App,
4394    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4395        let mut result = BTreeMap::new();
4396        self.suggested_indents_callback(
4397            rows,
4398            &mut |row, indent| {
4399                result.insert(row, indent);
4400                ControlFlow::Continue(())
4401            },
4402            cx,
4403        );
4404        result
4405    }
4406
4407    // move this to be a generator once those are a thing
4408    pub fn suggested_indents_callback(
4409        &self,
4410        rows: impl IntoIterator<Item = u32>,
4411        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4412        cx: &App,
4413    ) {
4414        let mut rows_for_excerpt = Vec::new();
4415        let mut cursor = self.cursor::<Point, Point>();
4416        let mut rows = rows.into_iter().peekable();
4417        let mut prev_row = u32::MAX;
4418        let mut prev_language_indent_size = IndentSize::default();
4419
4420        while let Some(row) = rows.next() {
4421            cursor.seek(&Point::new(row, 0));
4422            let Some(region) = cursor.region() else {
4423                continue;
4424            };
4425
4426            // Retrieve the language and indent size once for each disjoint region being indented.
4427            let single_indent_size = if row.saturating_sub(1) == prev_row {
4428                prev_language_indent_size
4429            } else {
4430                region
4431                    .buffer
4432                    .language_indent_size_at(Point::new(row, 0), cx)
4433            };
4434            prev_language_indent_size = single_indent_size;
4435            prev_row = row;
4436
4437            let start_buffer_row = region.buffer_range.start.row;
4438            let start_multibuffer_row = region.range.start.row;
4439            let end_multibuffer_row = region.range.end.row;
4440
4441            rows_for_excerpt.push(row);
4442            while let Some(next_row) = rows.peek().copied() {
4443                if end_multibuffer_row > next_row {
4444                    rows_for_excerpt.push(next_row);
4445                    rows.next();
4446                } else {
4447                    break;
4448                }
4449            }
4450
4451            let buffer_rows = rows_for_excerpt
4452                .drain(..)
4453                .map(|row| start_buffer_row + row - start_multibuffer_row);
4454            let buffer_indents = region
4455                .buffer
4456                .suggested_indents(buffer_rows, single_indent_size);
4457            for (row, indent) in buffer_indents {
4458                if cb(
4459                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4460                    indent,
4461                )
4462                .is_break()
4463                {
4464                    return;
4465                }
4466            }
4467        }
4468    }
4469
4470    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4471        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4472            let mut size = buffer.indent_size_for_line(range.start.row);
4473            size.len = size
4474                .len
4475                .min(range.end.column)
4476                .saturating_sub(range.start.column);
4477            size
4478        } else {
4479            IndentSize::spaces(0)
4480        }
4481    }
4482
4483    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4484        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4485            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4486        } else {
4487            LineIndent::spaces(0)
4488        }
4489    }
4490
4491    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4492        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4493
4494        if self.language_settings(cx).extend_comment_on_newline
4495            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4496        {
4497            let delimiters = language_scope.line_comment_prefixes();
4498            for delimiter in delimiters {
4499                if *self
4500                    .chars_at(Point::new(row.0, indent.len() as u32))
4501                    .take(delimiter.chars().count())
4502                    .collect::<String>()
4503                    .as_str()
4504                    == **delimiter
4505                {
4506                    indent.push_str(delimiter);
4507                    break;
4508                }
4509            }
4510        }
4511
4512        indent
4513    }
4514
4515    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4516    where
4517        T: ToOffset,
4518    {
4519        for char in self.reversed_chars_at(position) {
4520            if !char.is_whitespace() {
4521                return false;
4522            }
4523            if char == '\n' {
4524                return true;
4525            }
4526        }
4527        true
4528    }
4529
4530    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4531        while row.0 > 0 {
4532            row.0 -= 1;
4533            if !self.is_line_blank(row) {
4534                return Some(row);
4535            }
4536        }
4537        None
4538    }
4539
4540    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4541        if let Some((_, range)) = self.buffer_line_for_row(row) {
4542            range.end.column - range.start.column
4543        } else {
4544            0
4545        }
4546    }
4547
4548    pub fn buffer_line_for_row(
4549        &self,
4550        row: MultiBufferRow,
4551    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4552        let mut cursor = self.cursor::<Point, Point>();
4553        let point = Point::new(row.0, 0);
4554        cursor.seek(&point);
4555        let region = cursor.region()?;
4556        let overshoot = point.min(region.range.end) - region.range.start;
4557        let buffer_point = region.buffer_range.start + overshoot;
4558        if buffer_point.row > region.buffer_range.end.row {
4559            return None;
4560        }
4561        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4562        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4563            .min(region.buffer_range.end);
4564        Some((region.buffer, line_start..line_end))
4565    }
4566
4567    pub fn max_point(&self) -> Point {
4568        self.text_summary().lines
4569    }
4570
4571    pub fn max_row(&self) -> MultiBufferRow {
4572        MultiBufferRow(self.text_summary().lines.row)
4573    }
4574
4575    pub fn text_summary(&self) -> MBTextSummary {
4576        self.diff_transforms.summary().output
4577    }
4578
4579    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4580    where
4581        MBD: MultiBufferDimension + AddAssign,
4582        O: ToOffset,
4583    {
4584        let range = range.start.to_offset(self)..range.end.to_offset(self);
4585        let mut cursor = self
4586            .diff_transforms
4587            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4588        cursor.seek(&range.start, Bias::Right);
4589
4590        let Some(first_transform) = cursor.item() else {
4591            return MBD::from_summary(&MBTextSummary::default());
4592        };
4593
4594        let diff_transform_start = cursor.start().0;
4595        let diff_transform_end = cursor.end().0;
4596        let diff_start = range.start;
4597        let start_overshoot = diff_start - diff_transform_start;
4598        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4599
4600        let mut result = match first_transform {
4601            DiffTransform::BufferContent { .. } => {
4602                let excerpt_start = cursor.start().1 + start_overshoot;
4603                let excerpt_end = cursor.start().1 + end_overshoot;
4604                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4605            }
4606            DiffTransform::DeletedHunk {
4607                buffer_id,
4608                base_text_byte_range,
4609                has_trailing_newline,
4610                ..
4611            } => {
4612                let buffer_start = base_text_byte_range.start + start_overshoot;
4613                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4614                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4615                    panic!("{:?} is in non-existent deleted hunk", range.start)
4616                };
4617
4618                let include_trailing_newline =
4619                    *has_trailing_newline && range.end >= diff_transform_end;
4620                if include_trailing_newline {
4621                    buffer_end -= 1;
4622                }
4623
4624                let mut summary = base_text
4625                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4626
4627                if include_trailing_newline {
4628                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4629                        &TextSummary::newline(),
4630                    ))
4631                }
4632
4633                let mut result = MBD::default();
4634                result.add_text_dim(&summary);
4635                result
4636            }
4637        };
4638        if range.end < diff_transform_end {
4639            return result;
4640        }
4641
4642        cursor.next();
4643        result.add_mb_text_summary(
4644            &cursor
4645                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4646                .0,
4647        );
4648
4649        let Some(last_transform) = cursor.item() else {
4650            return result;
4651        };
4652
4653        let overshoot = range.end - cursor.start().0;
4654        let suffix = match last_transform {
4655            DiffTransform::BufferContent { .. } => {
4656                let end = cursor.start().1 + overshoot;
4657                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4658            }
4659            DiffTransform::DeletedHunk {
4660                base_text_byte_range,
4661                buffer_id,
4662                has_trailing_newline,
4663                ..
4664            } => {
4665                let buffer_end = base_text_byte_range.start + overshoot;
4666                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4667                    panic!("{:?} is in non-existent deleted hunk", range.end)
4668                };
4669
4670                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4671                    base_text_byte_range.start..buffer_end,
4672                );
4673                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4674                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4675                        &TextSummary::from("\n"),
4676                    ))
4677                }
4678
4679                let mut result = MBD::default();
4680                result.add_text_dim(&suffix);
4681                result
4682            }
4683        };
4684
4685        result += suffix;
4686        result
4687    }
4688
4689    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4690    where
4691        MBD: MultiBufferDimension + AddAssign,
4692    {
4693        let mut summary = MBD::default();
4694        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4695        cursor.seek(&range.start, Bias::Right);
4696        if let Some(excerpt) = cursor.item() {
4697            let buffer_snapshot = excerpt.buffer_snapshot(self);
4698            let mut end_before_newline = cursor.end();
4699            if excerpt.has_trailing_newline {
4700                end_before_newline -= 1;
4701            }
4702
4703            let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4704            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4705            let end_in_excerpt =
4706                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4707            summary.add_text_dim(
4708                &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4709                    start_in_excerpt..end_in_excerpt,
4710                ),
4711            );
4712
4713            if range.end > end_before_newline {
4714                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4715            }
4716
4717            cursor.next();
4718        }
4719
4720        if range.end > *cursor.start() {
4721            summary += cursor
4722                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4723                .0;
4724            if let Some(excerpt) = cursor.item() {
4725                let buffer_snapshot = excerpt.buffer_snapshot(self);
4726                range.end = cmp::max(*cursor.start(), range.end);
4727
4728                let excerpt_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
4729                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4730                summary.add_text_dim(
4731                    &buffer_snapshot.text_summary_for_range::<MBD::TextDimension, _>(
4732                        excerpt_start..end_in_excerpt,
4733                    ),
4734                );
4735            }
4736        }
4737
4738        summary
4739    }
4740
4741    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4742    where
4743        MBD: MultiBufferDimension
4744            + Ord
4745            + Sub<Output = MBD::TextDimension>
4746            + Sub<MBD::TextDimension, Output = MBD>
4747            + AddAssign<MBD::TextDimension>
4748            + Add<MBD::TextDimension, Output = MBD>,
4749        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4750    {
4751        let target = anchor.seek_target(self);
4752        let anchor = match anchor {
4753            Anchor::Min => {
4754                return MBD::default();
4755            }
4756            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4757            Anchor::Max => {
4758                return MBD::from_summary(&self.text_summary());
4759            }
4760        };
4761
4762        let (start, _, item) = self
4763            .excerpts
4764            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4765        let start = MBD::from_summary(&start.text);
4766
4767        let excerpt_start_position = ExcerptDimension(start);
4768        if self.diff_transforms.is_empty() {
4769            if let Some(excerpt) = item {
4770                if !excerpt.contains(anchor, self) {
4771                    return excerpt_start_position.0;
4772                }
4773                let buffer_snapshot = excerpt.buffer_snapshot(self);
4774                let excerpt_buffer_start = excerpt
4775                    .range
4776                    .context
4777                    .start
4778                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4779                let excerpt_buffer_end = excerpt
4780                    .range
4781                    .context
4782                    .end
4783                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4784                let buffer_summary = anchor
4785                    .text_anchor()
4786                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4787                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4788                let mut position = excerpt_start_position;
4789                if summary > excerpt_buffer_start {
4790                    position += summary - excerpt_buffer_start;
4791                }
4792
4793                position.0
4794            } else {
4795                excerpt_start_position.0
4796            }
4797        } else {
4798            let mut diff_transforms_cursor = self
4799                .diff_transforms
4800                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4801            diff_transforms_cursor.next();
4802
4803            if let Some(excerpt) = item {
4804                if !excerpt.contains(anchor, self) {
4805                    return self.summary_for_excerpt_position_without_hunks(
4806                        Bias::Left,
4807                        excerpt_start_position,
4808                        &mut diff_transforms_cursor,
4809                    );
4810                }
4811                let buffer_snapshot = excerpt.buffer_snapshot(self);
4812                let excerpt_buffer_start = excerpt
4813                    .range
4814                    .context
4815                    .start
4816                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4817                let excerpt_buffer_end = excerpt
4818                    .range
4819                    .context
4820                    .end
4821                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4822                let buffer_summary = anchor
4823                    .text_anchor()
4824                    .summary::<MBD::TextDimension>(&buffer_snapshot);
4825                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4826                let mut position = excerpt_start_position;
4827                if summary > excerpt_buffer_start {
4828                    position += summary - excerpt_buffer_start;
4829                }
4830
4831                if diff_transforms_cursor.start().0 < position {
4832                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
4833                }
4834                self.summary_for_anchor_with_excerpt_position(
4835                    *anchor,
4836                    position,
4837                    &mut diff_transforms_cursor,
4838                    &buffer_snapshot,
4839                )
4840            } else {
4841                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
4842                self.summary_for_excerpt_position_without_hunks(
4843                    Bias::Right,
4844                    excerpt_start_position,
4845                    &mut diff_transforms_cursor,
4846                )
4847            }
4848        }
4849    }
4850
4851    /// Maps an anchor's excerpt-space position to its output-space position by
4852    /// walking the diff transforms. The cursor is shared across consecutive
4853    /// calls, so it may already be partway through the transform list.
4854    fn summary_for_anchor_with_excerpt_position<MBD>(
4855        &self,
4856        anchor: ExcerptAnchor,
4857        excerpt_position: ExcerptDimension<MBD>,
4858        diff_transforms: &mut Cursor<
4859            DiffTransform,
4860            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4861        >,
4862        excerpt_buffer: &text::BufferSnapshot,
4863    ) -> MBD
4864    where
4865        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4866    {
4867        loop {
4868            let transform_end_position = diff_transforms.end().0;
4869            let item = diff_transforms.item();
4870            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4871
4872            // A right-biased anchor at a transform boundary belongs to the
4873            // *next* transform, so advance past the current one.
4874            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
4875                diff_transforms.next();
4876                continue;
4877            }
4878
4879            let mut position = diff_transforms.start().1;
4880            match item {
4881                Some(DiffTransform::DeletedHunk {
4882                    buffer_id,
4883                    base_text_byte_range,
4884                    hunk_info,
4885                    ..
4886                }) => {
4887                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
4888                        && let Some(base_text) =
4889                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4890                        && diff_base_anchor.is_valid(&base_text)
4891                    {
4892                        // The anchor carries a diff-base position — resolve it
4893                        // to a location inside the deleted hunk.
4894                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4895                        if base_text_offset >= base_text_byte_range.start
4896                            && base_text_offset <= base_text_byte_range.end
4897                        {
4898                            let position_in_hunk = base_text
4899                                .text_summary_for_range::<MBD::TextDimension, _>(
4900                                    base_text_byte_range.start..base_text_offset,
4901                                );
4902                            position.0.add_text_dim(&position_in_hunk);
4903                        } else if at_transform_end {
4904                            // diff_base offset falls outside this hunk's range;
4905                            // advance to see if the next transform is a better fit.
4906                            diff_transforms.next();
4907                            continue;
4908                        }
4909                    } else if at_transform_end
4910                        && anchor
4911                            .text_anchor()
4912                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
4913                            .is_gt()
4914                    {
4915                        // The anchor has no (valid) diff-base position, so it
4916                        // belongs in the buffer content, not in the deleted
4917                        // hunk. However, after an edit deletes the text between
4918                        // the hunk boundary and this anchor, both resolve to
4919                        // the same excerpt_position—landing us here on the
4920                        // DeletedHunk left behind by the shared cursor. Use the
4921                        // CRDT ordering to detect that the anchor is strictly
4922                        // *past* the hunk boundary and skip to the following
4923                        // BufferContent.
4924                        diff_transforms.next();
4925                        continue;
4926                    }
4927                }
4928                _ => {
4929                    // On a BufferContent (or no transform). If the anchor
4930                    // carries a diff_base_anchor it needs a DeletedHunk, so
4931                    // advance to find one.
4932                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4933                        diff_transforms.next();
4934                        continue;
4935                    }
4936                    let overshoot = excerpt_position - diff_transforms.start().0;
4937                    position += overshoot;
4938                }
4939            }
4940
4941            return position.0;
4942        }
4943    }
4944
4945    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
4946    fn summary_for_excerpt_position_without_hunks<MBD>(
4947        &self,
4948        bias: Bias,
4949        excerpt_position: ExcerptDimension<MBD>,
4950        diff_transforms: &mut Cursor<
4951            DiffTransform,
4952            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4953        >,
4954    ) -> MBD
4955    where
4956        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4957    {
4958        loop {
4959            let transform_end_position = diff_transforms.end().0;
4960            let item = diff_transforms.item();
4961            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
4962
4963            // A right-biased anchor at a transform boundary belongs to the
4964            // *next* transform, so advance past the current one.
4965            if bias == Bias::Right && at_transform_end {
4966                diff_transforms.next();
4967                continue;
4968            }
4969
4970            let mut position = diff_transforms.start().1;
4971            if let Some(DiffTransform::BufferContent { .. }) | None = item {
4972                let overshoot = excerpt_position - diff_transforms.start().0;
4973                position += overshoot;
4974            }
4975
4976            return position.0;
4977        }
4978    }
4979
4980    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4981        let anchor = match anchor {
4982            Anchor::Min => return ExcerptOffset::default(),
4983            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4984            Anchor::Max => return self.excerpts.summary().len(),
4985        };
4986        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4987        let target = anchor.seek_target(self);
4988
4989        cursor.seek(&target, Bias::Left);
4990
4991        let mut position = cursor.start().len();
4992        if let Some(excerpt) = cursor.item()
4993            && excerpt.contains(anchor, self)
4994        {
4995            let buffer_snapshot = excerpt.buffer_snapshot(self);
4996            let excerpt_buffer_start =
4997                buffer_snapshot.offset_for_anchor(&excerpt.range.context.start);
4998            let excerpt_buffer_end = buffer_snapshot.offset_for_anchor(&excerpt.range.context.end);
4999            let buffer_position = cmp::min(
5000                excerpt_buffer_end,
5001                buffer_snapshot.offset_for_anchor(&anchor.text_anchor()),
5002            );
5003            if buffer_position > excerpt_buffer_start {
5004                position += buffer_position - excerpt_buffer_start;
5005            }
5006        }
5007        position
5008    }
5009
5010    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5011    where
5012        MBD: MultiBufferDimension
5013            + Ord
5014            + Sub<Output = MBD::TextDimension>
5015            + AddAssign<MBD::TextDimension>,
5016        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5017        I: 'a + IntoIterator<Item = &'a Anchor>,
5018    {
5019        let mut anchors = anchors.into_iter().peekable();
5020        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5021        let mut diff_transforms_cursor = self
5022            .diff_transforms
5023            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5024        diff_transforms_cursor.next();
5025
5026        let mut summaries = Vec::new();
5027        while let Some(anchor) = anchors.peek() {
5028            let target = anchor.seek_target(self);
5029            let excerpt_anchor = match anchor {
5030                Anchor::Min => {
5031                    summaries.push(MBD::default());
5032                    anchors.next();
5033                    continue;
5034                }
5035                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5036                Anchor::Max => {
5037                    summaries.push(MBD::from_summary(&self.text_summary()));
5038                    anchors.next();
5039                    continue;
5040                }
5041            };
5042
5043            cursor.seek_forward(&target, Bias::Left);
5044
5045            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5046            if let Some(excerpt) = cursor.item() {
5047                let buffer_snapshot = excerpt.buffer_snapshot(self);
5048                if !excerpt.contains(&excerpt_anchor, self) {
5049                    let position = self.summary_for_excerpt_position_without_hunks(
5050                        Bias::Left,
5051                        excerpt_start_position,
5052                        &mut diff_transforms_cursor,
5053                    );
5054                    summaries.push(position);
5055                    anchors.next();
5056                    continue;
5057                }
5058                let excerpt_buffer_start = excerpt
5059                    .range
5060                    .context
5061                    .start
5062                    .summary::<MBD::TextDimension>(buffer_snapshot);
5063                let excerpt_buffer_end = excerpt
5064                    .range
5065                    .context
5066                    .end
5067                    .summary::<MBD::TextDimension>(buffer_snapshot);
5068                for (buffer_summary, excerpt_anchor) in buffer_snapshot
5069                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5070                        std::iter::from_fn(|| {
5071                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5072                            if !excerpt.contains(&excerpt_anchor, self) {
5073                                return None;
5074                            }
5075                            anchors.next();
5076                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5077                        }),
5078                    )
5079                {
5080                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5081                    let mut position = excerpt_start_position;
5082                    if summary > excerpt_buffer_start {
5083                        position += summary - excerpt_buffer_start;
5084                    }
5085
5086                    if diff_transforms_cursor.start().0 < position {
5087                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5088                    }
5089
5090                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5091                        excerpt_anchor,
5092                        position,
5093                        &mut diff_transforms_cursor,
5094                        &buffer_snapshot,
5095                    ));
5096                }
5097            } else {
5098                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5099                let position = self.summary_for_excerpt_position_without_hunks(
5100                    Bias::Right,
5101                    excerpt_start_position,
5102                    &mut diff_transforms_cursor,
5103                );
5104                summaries.push(position);
5105                anchors.next();
5106            }
5107        }
5108
5109        summaries
5110    }
5111
5112    pub fn dimensions_from_points<'a, MBD>(
5113        &'a self,
5114        points: impl 'a + IntoIterator<Item = Point>,
5115    ) -> impl 'a + Iterator<Item = MBD>
5116    where
5117        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5118    {
5119        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5120        cursor.seek(&DimensionPair {
5121            key: Point::default(),
5122            value: None,
5123        });
5124        let mut points = points.into_iter();
5125        iter::from_fn(move || {
5126            let point = points.next()?;
5127
5128            cursor.seek_forward(&DimensionPair {
5129                key: point,
5130                value: None,
5131            });
5132
5133            if let Some(region) = cursor.region() {
5134                let overshoot = point - region.range.start.key;
5135                let buffer_point = region.buffer_range.start + overshoot;
5136                let mut position = region.range.start.value.unwrap();
5137                position.add_text_dim(
5138                    &region
5139                        .buffer
5140                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5141                );
5142                if point == region.range.end.key && region.has_trailing_newline {
5143                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5144                }
5145                Some(position)
5146            } else {
5147                Some(MBD::from_summary(&self.text_summary()))
5148            }
5149        })
5150    }
5151
5152    fn excerpts_for_buffer(&self, buffer_id: BufferId) -> impl Iterator<Item = &Excerpt> {
5153        if let Some(buffer_state) = self.buffers.get(&buffer_id) {
5154            let path_key = buffer_state.path_key.clone();
5155            let mut cursor = self.excerpts.cursor::<PathKey>(());
5156            cursor.seek_forward(&path_key, Bias::Left);
5157            Some(iter::from_fn(move || {
5158                let excerpt = cursor.item()?;
5159                if excerpt.path_key != path_key {
5160                    return None;
5161                }
5162                cursor.next();
5163                Some(excerpt)
5164            }))
5165        } else {
5166            None
5167        }
5168        .into_iter()
5169        .flatten()
5170    }
5171
5172    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5173        self.anchor_at(position, Bias::Left)
5174    }
5175
5176    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5177        self.anchor_at(position, Bias::Right)
5178    }
5179
5180    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5181        let offset = position.to_offset(self);
5182
5183        // Find the given position in the diff transforms. Determine the corresponding
5184        // offset in the excerpts, and whether the position is within a deleted hunk.
5185        let mut diff_transforms = self
5186            .diff_transforms
5187            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5188        diff_transforms.seek(&offset, Bias::Right);
5189
5190        if offset == diff_transforms.start().0
5191            && bias == Bias::Left
5192            && let Some(prev_item) = diff_transforms.prev_item()
5193            && let DiffTransform::DeletedHunk { .. } = prev_item
5194        {
5195            diff_transforms.prev();
5196        }
5197        let offset_in_transform = offset - diff_transforms.start().0;
5198        let mut excerpt_offset = diff_transforms.start().1;
5199        let mut diff_base_anchor = None;
5200        if let Some(DiffTransform::DeletedHunk {
5201            buffer_id,
5202            base_text_byte_range,
5203            has_trailing_newline,
5204            ..
5205        }) = diff_transforms.item()
5206        {
5207            let diff = self.diffs.get(buffer_id).expect("missing diff");
5208            if offset_in_transform > base_text_byte_range.len() {
5209                debug_assert!(*has_trailing_newline);
5210                bias = Bias::Right;
5211            } else {
5212                diff_base_anchor = Some(
5213                    diff.base_text()
5214                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5215                );
5216                bias = Bias::Left;
5217            }
5218        } else {
5219            excerpt_offset += MultiBufferOffset(offset_in_transform);
5220        };
5221
5222        let mut excerpts = self
5223            .excerpts
5224            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5225        excerpts.seek(&excerpt_offset, Bias::Right);
5226        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5227            excerpts.prev();
5228        }
5229        if let Some(excerpt) = excerpts.item() {
5230            let buffer_snapshot = excerpt.buffer_snapshot(self);
5231            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5232            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5233                overshoot -= 1;
5234                bias = Bias::Right;
5235            }
5236
5237            let buffer_start = excerpt.range.context.start.to_offset(&buffer_snapshot);
5238            let text_anchor = excerpt.clip_anchor(
5239                buffer_snapshot.anchor_at(buffer_start + overshoot, bias),
5240                self,
5241            );
5242            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5243            let anchor = match diff_base_anchor {
5244                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5245                None => anchor,
5246            };
5247            anchor.into()
5248        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5249        {
5250            Anchor::min()
5251        } else {
5252            Anchor::max()
5253        }
5254    }
5255
5256    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5257    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5258        let buffer = self.as_singleton()?;
5259        if text_anchor.buffer_id == buffer.remote_id() {
5260            // todo!() bit hacky, but always right for singletons
5261            Some(Anchor::in_buffer(PathKeyIndex(0), text_anchor))
5262        } else {
5263            None
5264        }
5265    }
5266
5267    /// Creates a multibuffer anchor range for the given buffer anchor range, if any excerpt contains both endpoints.
5268    pub fn anchor_range_in_buffer(
5269        &self,
5270        buffer_id: BufferId,
5271        text_anchor: Range<text::Anchor>,
5272    ) -> Option<Range<Anchor>> {
5273        for excerpt in self.excerpts_for_buffer(buffer_id) {
5274            let buffer_snapshot = excerpt.buffer_snapshot(self);
5275            if excerpt.range.contains(&text_anchor.start, &buffer_snapshot)
5276                && excerpt.range.contains(&text_anchor.end, &buffer_snapshot)
5277            {
5278                return Some(Anchor::range_in_buffer(excerpt.path_key_index, text_anchor));
5279            }
5280        }
5281
5282        None
5283    }
5284
5285    /// Creates a multibuffer anchor for the given buffer anchor, if it is contained in any excerpt.
5286    pub fn anchor_in_buffer(
5287        &self,
5288        buffer_id: BufferId,
5289        text_anchor: text::Anchor,
5290    ) -> Option<Anchor> {
5291        for excerpt in self.excerpts_for_buffer(buffer_id) {
5292            let buffer_snapshot = excerpt.buffer_snapshot(self);
5293            if excerpt.range.contains(&text_anchor, &buffer_snapshot) {
5294                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5295            }
5296        }
5297
5298        None
5299    }
5300
5301    pub fn anchors_in_buffer(
5302        &self,
5303        buffer_id: BufferId,
5304        text_anchors: impl IntoIterator<Item = text::Anchor>,
5305    ) -> Option<impl Iterator<Item = Anchor>> {
5306        let path_key_index = self.path_key_index_for_buffer(buffer_id)?;
5307        Some(
5308            text_anchors
5309                .into_iter()
5310                .map(move |anchor| Anchor::in_buffer(path_key_index, anchor)),
5311        )
5312    }
5313
5314    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5315        match anchor {
5316            // todo(lw): should be `!self.is_empty()`
5317            Anchor::Min | Anchor::Max => true,
5318            Anchor::Excerpt(excerpt_anchor) => {
5319                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5320                    return false;
5321                };
5322                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5323                cursor.seek(&target, Bias::Left);
5324                let Some(excerpt) = cursor.item() else {
5325                    return false;
5326                };
5327                excerpt
5328                    .buffer_snapshot(self)
5329                    .can_resolve(&excerpt_anchor.text_anchor())
5330            }
5331        }
5332    }
5333
5334    pub fn excerpts(&self) -> impl Iterator<Item = (&BufferSnapshot, ExcerptInfo)> {
5335        self.excerpts
5336            .iter()
5337            .map(|excerpt| (excerpt.buffer_snapshot(self), excerpt.info()))
5338    }
5339
5340    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5341    where
5342        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5343        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5344    {
5345        let excerpts = self.excerpts.cursor(());
5346        let diff_transforms = self.diff_transforms.cursor(());
5347        MultiBufferCursor {
5348            excerpts,
5349            diff_transforms,
5350            cached_region: OnceCell::new(),
5351            snapshot: self,
5352        }
5353    }
5354
5355    pub fn excerpt_before(&self, anchor: Anchor) -> Option<ExcerptInfo> {
5356        let target = anchor.try_seek_target(&self)?;
5357        let mut excerpts = self.excerpts.cursor::<ExcerptSummary>(());
5358        excerpts.seek(&target, Bias::Left);
5359        excerpts.prev();
5360        Some(excerpts.item()?.info())
5361    }
5362
5363    pub fn excerpt_boundaries_in_range<R, T>(
5364        &self,
5365        range: R,
5366    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5367    where
5368        R: RangeBounds<T>,
5369        T: ToOffset,
5370    {
5371        let start_offset;
5372        let start = match range.start_bound() {
5373            Bound::Included(start) => {
5374                start_offset = start.to_offset(self);
5375                Bound::Included(start_offset)
5376            }
5377            Bound::Excluded(_) => {
5378                panic!("not supported")
5379            }
5380            Bound::Unbounded => {
5381                start_offset = MultiBufferOffset::ZERO;
5382                Bound::Unbounded
5383            }
5384        };
5385        let end = match range.end_bound() {
5386            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5387            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5388            Bound::Unbounded => Bound::Unbounded,
5389        };
5390        let bounds = (start, end);
5391        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5392        cursor.seek(&DimensionPair {
5393            key: start_offset,
5394            value: None,
5395        });
5396
5397        if cursor
5398            .fetch_excerpt_with_range()
5399            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5400        {
5401            cursor.prev_excerpt();
5402        } else {
5403            cursor.seek_to_start_of_current_excerpt();
5404        }
5405        let mut prev_excerpt = cursor
5406            .fetch_excerpt_with_range()
5407            .map(|(excerpt, _)| excerpt);
5408
5409        cursor.next_excerpt_forwards();
5410
5411        iter::from_fn(move || {
5412            loop {
5413                if self.singleton {
5414                    return None;
5415                }
5416
5417                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5418                cursor.next_excerpt_forwards();
5419                if !bounds.contains(&next_range.start.key) {
5420                    prev_excerpt = Some(next_excerpt);
5421                    continue;
5422                }
5423
5424                let next_region_start = next_range.start.value.unwrap();
5425                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5426                    range.start.value.unwrap()
5427                } else {
5428                    self.max_point()
5429                };
5430
5431                let prev = prev_excerpt.as_ref().map(|excerpt| ExcerptBoundaryInfo {
5432                    path_key_index: excerpt.path_key_index,
5433                    buffer: excerpt.buffer_snapshot(self).clone(),
5434                    range: excerpt.range.clone(),
5435                    end_row: MultiBufferRow(next_region_start.row),
5436                });
5437
5438                let next = ExcerptBoundaryInfo {
5439                    path_key_index: next_excerpt.path_key_index,
5440                    buffer: next_excerpt.buffer_snapshot(self).clone(),
5441                    range: next_excerpt.range.clone(),
5442                    end_row: if next_excerpt.has_trailing_newline {
5443                        MultiBufferRow(next_region_end.row - 1)
5444                    } else {
5445                        MultiBufferRow(next_region_end.row)
5446                    },
5447                };
5448
5449                let row = MultiBufferRow(next_region_start.row);
5450
5451                prev_excerpt = Some(next_excerpt);
5452
5453                return Some(ExcerptBoundary { row, prev, next });
5454            }
5455        })
5456    }
5457
5458    pub fn edit_count(&self) -> usize {
5459        self.edit_count
5460    }
5461
5462    pub fn non_text_state_update_count(&self) -> usize {
5463        self.non_text_state_update_count
5464    }
5465
5466    /// Returns the smallest enclosing bracket ranges containing the given range or
5467    /// None if no brackets contain range or the range is not contained in a single
5468    /// excerpt
5469    ///
5470    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5471    #[ztracing::instrument(skip_all)]
5472    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5473        &self,
5474        range: Range<T>,
5475        range_filter: Option<
5476            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5477        >,
5478    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5479        let range = range.start.to_offset(self)..range.end.to_offset(self);
5480        let mut excerpt = self.excerpt_containing(range.clone())?;
5481        let buffer_snapshot = excerpt.buffer(self).clone();
5482        let excerpt_buffer_range = excerpt.buffer_range(self);
5483
5484        // Filter to ranges contained in the excerpt
5485        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5486            excerpt_buffer_range.contains(&BufferOffset(open.start))
5487                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5488                && range_filter.is_none_or(|filter| {
5489                    filter(
5490                        &buffer_snapshot,
5491                        BufferOffset(open.start)..BufferOffset(close.end),
5492                        BufferOffset(close.start)..BufferOffset(close.end),
5493                    )
5494                })
5495        };
5496
5497        let (open, close) = buffer_snapshot.innermost_enclosing_bracket_ranges(
5498            excerpt.map_range_to_buffer(range),
5499            Some(&range_filter),
5500        )?;
5501
5502        Some((
5503            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5504            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5505        ))
5506    }
5507
5508    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5509    /// not contained in a single excerpt
5510    pub fn enclosing_bracket_ranges<T: ToOffset>(
5511        &self,
5512        range: Range<T>,
5513    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5514    {
5515        let range = range.start.to_offset(self)..range.end.to_offset(self);
5516        let mut excerpt = self.excerpt_containing(range.clone())?;
5517
5518        Some(
5519            excerpt
5520                .buffer(self)
5521                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5522                .filter_map(move |pair| {
5523                    let open_range =
5524                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5525                    let close_range =
5526                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5527                    if excerpt.contains_buffer_range(open_range.start..close_range.end, self) {
5528                        Some((
5529                            excerpt.map_range_from_buffer(open_range),
5530                            excerpt.map_range_from_buffer(close_range),
5531                        ))
5532                    } else {
5533                        None
5534                    }
5535                }),
5536        )
5537    }
5538
5539    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5540    /// not contained in a single excerpt
5541    pub fn text_object_ranges<T: ToOffset>(
5542        &self,
5543        range: Range<T>,
5544        options: TreeSitterOptions,
5545    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5546        let range = range.start.to_offset(self)..range.end.to_offset(self);
5547        self.excerpt_containing(range.clone())
5548            .map(|mut excerpt| {
5549                excerpt
5550                    .buffer(self)
5551                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5552                    .filter_map(move |(range, text_object)| {
5553                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5554                        if excerpt.contains_buffer_range(range.clone(), self) {
5555                            Some((excerpt.map_range_from_buffer(range), text_object))
5556                        } else {
5557                            None
5558                        }
5559                    })
5560            })
5561            .into_iter()
5562            .flatten()
5563    }
5564
5565    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5566    /// not contained in a single excerpt
5567    pub fn bracket_ranges<T: ToOffset>(
5568        &self,
5569        range: Range<T>,
5570    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5571    {
5572        let range = range.start.to_offset(self)..range.end.to_offset(self);
5573        let mut excerpt = self.excerpt_containing(range.clone())?;
5574        Some(
5575            excerpt
5576                .buffer(self)
5577                .bracket_ranges(excerpt.map_range_to_buffer(range))
5578                .filter_map(move |pair| {
5579                    let open_range =
5580                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5581                    let close_range =
5582                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5583                    excerpt
5584                        .contains_buffer_range(open_range.start..close_range.end, self)
5585                        .then(|| BracketMatch {
5586                            open_range: excerpt.map_range_from_buffer(open_range),
5587                            close_range: excerpt.map_range_from_buffer(close_range),
5588                            color_index: pair.color_index,
5589                            newline_only: pair.newline_only,
5590                            syntax_layer_depth: pair.syntax_layer_depth,
5591                        })
5592                })
5593                .map(BracketMatch::bracket_ranges),
5594        )
5595    }
5596
5597    pub fn redacted_ranges<'a, T: ToOffset>(
5598        &'a self,
5599        range: Range<T>,
5600        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5601    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5602        let range = range.start.to_offset(self)..range.end.to_offset(self);
5603        self.lift_buffer_metadata(range, move |buffer, range| {
5604            if redaction_enabled(buffer.file()) {
5605                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5606            } else {
5607                None
5608            }
5609        })
5610        .map(|(range, _, _)| range)
5611    }
5612
5613    pub fn runnable_ranges(
5614        &self,
5615        range: Range<Anchor>,
5616    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5617        let range = range.start.to_offset(self)..range.end.to_offset(self);
5618        self.lift_buffer_metadata(range, move |buffer, range| {
5619            Some(
5620                buffer
5621                    .runnable_ranges(range.clone())
5622                    .filter(move |runnable| {
5623                        runnable.run_range.start >= range.start
5624                            && runnable.run_range.end < range.end
5625                    })
5626                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5627            )
5628        })
5629        .map(|(run_range, runnable, _)| (run_range, runnable))
5630    }
5631
5632    pub fn line_indents(
5633        &self,
5634        start_row: MultiBufferRow,
5635        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5636    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5637        let max_point = self.max_point();
5638        let mut cursor = self.cursor::<Point, Point>();
5639        cursor.seek(&Point::new(start_row.0, 0));
5640        iter::from_fn(move || {
5641            let mut region = cursor.region()?;
5642            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5643                cursor.next();
5644                region = cursor.region()?;
5645            }
5646            let region = cursor.region()?;
5647            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5648            let buffer_start_row =
5649                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5650
5651            let buffer_end_row = if region.is_main_buffer
5652                && (region.has_trailing_newline || region.range.end == max_point)
5653            {
5654                region.buffer_range.end.row
5655            } else {
5656                region.buffer_range.end.row.saturating_sub(1)
5657            };
5658
5659            let line_indents = region
5660                .buffer
5661                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5662            let region_buffer_row = region.buffer_range.start.row;
5663            let region_row = region.range.start.row;
5664            let region_buffer = region.excerpt.buffer_snapshot(self);
5665            cursor.next();
5666            Some(line_indents.map(move |(buffer_row, indent)| {
5667                let row = region_row + (buffer_row - region_buffer_row);
5668                (MultiBufferRow(row), indent, region_buffer)
5669            }))
5670        })
5671        .flatten()
5672    }
5673
5674    pub fn reversed_line_indents(
5675        &self,
5676        end_row: MultiBufferRow,
5677        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5678    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5679        let max_point = self.max_point();
5680        let mut cursor = self.cursor::<Point, Point>();
5681        cursor.seek(&Point::new(end_row.0, 0));
5682        iter::from_fn(move || {
5683            let mut region = cursor.region()?;
5684            while !buffer_filter(&region.excerpt.buffer_snapshot(self)) {
5685                cursor.prev();
5686                region = cursor.region()?;
5687            }
5688            let region = cursor.region()?;
5689
5690            let buffer_start_row = region.buffer_range.start.row;
5691            let buffer_end_row = if region.is_main_buffer
5692                && (region.has_trailing_newline || region.range.end == max_point)
5693            {
5694                region.buffer_range.end.row + 1
5695            } else {
5696                region.buffer_range.end.row
5697            };
5698
5699            let overshoot = end_row.0 - region.range.start.row;
5700            let buffer_end_row =
5701                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5702
5703            let line_indents = region
5704                .buffer
5705                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5706            let region_buffer_row = region.buffer_range.start.row;
5707            let region_row = region.range.start.row;
5708            let region_buffer = region.excerpt.buffer_snapshot(self);
5709            cursor.prev();
5710            Some(line_indents.map(move |(buffer_row, indent)| {
5711                let row = region_row + (buffer_row - region_buffer_row);
5712                (MultiBufferRow(row), indent, region_buffer)
5713            }))
5714        })
5715        .flatten()
5716    }
5717
5718    pub async fn enclosing_indent(
5719        &self,
5720        mut target_row: MultiBufferRow,
5721    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5722        let max_row = MultiBufferRow(self.max_point().row);
5723        if target_row >= max_row {
5724            return None;
5725        }
5726
5727        let mut target_indent = self.line_indent_for_row(target_row);
5728
5729        // If the current row is at the start of an indented block, we want to return this
5730        // block as the enclosing indent.
5731        if !target_indent.is_line_empty() && target_row < max_row {
5732            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5733            if !next_line_indent.is_line_empty()
5734                && target_indent.raw_len() < next_line_indent.raw_len()
5735            {
5736                target_indent = next_line_indent;
5737                target_row.0 += 1;
5738            }
5739        }
5740
5741        const SEARCH_ROW_LIMIT: u32 = 25000;
5742        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5743        const YIELD_INTERVAL: u32 = 100;
5744
5745        let mut accessed_row_counter = 0;
5746
5747        // If there is a blank line at the current row, search for the next non indented lines
5748        if target_indent.is_line_empty() {
5749            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5750            let end =
5751                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5752
5753            let mut non_empty_line_above = None;
5754            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5755                if row < start {
5756                    break;
5757                }
5758                accessed_row_counter += 1;
5759                if accessed_row_counter == YIELD_INTERVAL {
5760                    accessed_row_counter = 0;
5761                    yield_now().await;
5762                }
5763                if !indent.is_line_empty() {
5764                    non_empty_line_above = Some((row, indent));
5765                    break;
5766                }
5767            }
5768
5769            let mut non_empty_line_below = None;
5770            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5771                if row > end {
5772                    break;
5773                }
5774                accessed_row_counter += 1;
5775                if accessed_row_counter == YIELD_INTERVAL {
5776                    accessed_row_counter = 0;
5777                    yield_now().await;
5778                }
5779                if !indent.is_line_empty() {
5780                    non_empty_line_below = Some((row, indent));
5781                    break;
5782                }
5783            }
5784
5785            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5786                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5787                    if above_indent.raw_len() >= below_indent.raw_len() {
5788                        (above_row, above_indent)
5789                    } else {
5790                        (below_row, below_indent)
5791                    }
5792                }
5793                (Some(above), None) => above,
5794                (None, Some(below)) => below,
5795                _ => return None,
5796            };
5797
5798            target_indent = indent;
5799            target_row = row;
5800        }
5801
5802        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5803        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5804
5805        let mut start_indent = None;
5806        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5807            if row < start {
5808                break;
5809            }
5810            accessed_row_counter += 1;
5811            if accessed_row_counter == YIELD_INTERVAL {
5812                accessed_row_counter = 0;
5813                yield_now().await;
5814            }
5815            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5816                start_indent = Some((row, indent));
5817                break;
5818            }
5819        }
5820        let (start_row, start_indent_size) = start_indent?;
5821
5822        let mut end_indent = (end, None);
5823        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5824            if row > end {
5825                break;
5826            }
5827            accessed_row_counter += 1;
5828            if accessed_row_counter == YIELD_INTERVAL {
5829                accessed_row_counter = 0;
5830                yield_now().await;
5831            }
5832            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5833                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5834                break;
5835            }
5836        }
5837        let (end_row, end_indent_size) = end_indent;
5838
5839        let indent = if let Some(end_indent_size) = end_indent_size {
5840            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5841                start_indent_size
5842            } else {
5843                end_indent_size
5844            }
5845        } else {
5846            start_indent_size
5847        };
5848
5849        Some((start_row..end_row, indent))
5850    }
5851
5852    pub fn indent_guides_in_range<T: ToPoint>(
5853        &self,
5854        range: Range<T>,
5855        ignore_disabled_for_language: bool,
5856        cx: &App,
5857    ) -> impl Iterator<Item = IndentGuide> {
5858        let range = range.start.to_point(self)..range.end.to_point(self);
5859        let start_row = MultiBufferRow(range.start.row);
5860        let end_row = MultiBufferRow(range.end.row);
5861
5862        let mut row_indents = self.line_indents(start_row, |buffer| {
5863            let settings =
5864                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5865            settings.indent_guides.enabled || ignore_disabled_for_language
5866        });
5867
5868        let mut result = Vec::new();
5869        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5870
5871        let mut prev_settings = None;
5872        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5873            if first_row > end_row {
5874                break;
5875            }
5876            let current_depth = indent_stack.len() as u32;
5877
5878            // Avoid retrieving the language settings repeatedly for every buffer row.
5879            if let Some((prev_buffer_id, _)) = &prev_settings
5880                && prev_buffer_id != &buffer.remote_id()
5881            {
5882                prev_settings.take();
5883            }
5884            let settings = &prev_settings
5885                .get_or_insert_with(|| {
5886                    (
5887                        buffer.remote_id(),
5888                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5889                    )
5890                })
5891                .1;
5892            let tab_size = settings.tab_size.get();
5893
5894            // When encountering empty, continue until found useful line indent
5895            // then add to the indent stack with the depth found
5896            let mut found_indent = false;
5897            let mut last_row = first_row;
5898            if line_indent.is_line_blank() {
5899                while !found_indent {
5900                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5901                        break;
5902                    };
5903                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5904                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5905                        break;
5906                    }
5907
5908                    if new_line_indent.is_line_blank() {
5909                        continue;
5910                    }
5911                    last_row = target_row.min(end_row);
5912                    line_indent = new_line_indent;
5913                    found_indent = true;
5914                    break;
5915                }
5916            } else {
5917                found_indent = true
5918            }
5919
5920            let depth = if found_indent {
5921                line_indent.len(tab_size) / tab_size
5922            } else {
5923                0
5924            };
5925
5926            match depth.cmp(&current_depth) {
5927                cmp::Ordering::Less => {
5928                    for _ in 0..(current_depth - depth) {
5929                        let mut indent = indent_stack.pop().unwrap();
5930                        if last_row != first_row {
5931                            // In this case, we landed on an empty row, had to seek forward,
5932                            // and discovered that the indent we where on is ending.
5933                            // This means that the last display row must
5934                            // be on line that ends this indent range, so we
5935                            // should display the range up to the first non-empty line
5936                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5937                        }
5938
5939                        result.push(indent)
5940                    }
5941                }
5942                cmp::Ordering::Greater => {
5943                    for next_depth in current_depth..depth {
5944                        indent_stack.push(IndentGuide {
5945                            buffer_id: buffer.remote_id(),
5946                            start_row: first_row,
5947                            end_row: last_row,
5948                            depth: next_depth,
5949                            tab_size,
5950                            settings: settings.indent_guides.clone(),
5951                        });
5952                    }
5953                }
5954                _ => {}
5955            }
5956
5957            for indent in indent_stack.iter_mut() {
5958                indent.end_row = last_row;
5959            }
5960        }
5961
5962        result.extend(indent_stack);
5963        result.into_iter()
5964    }
5965
5966    pub fn trailing_excerpt_update_count(&self) -> usize {
5967        self.trailing_excerpt_update_count
5968    }
5969
5970    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5971        self.point_to_buffer_offset(point)
5972            .and_then(|(buffer, _)| buffer.file())
5973    }
5974
5975    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
5976        self.point_to_buffer_offset(offset)
5977            .and_then(|(buffer, offset)| buffer.language_at(offset))
5978    }
5979
5980    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5981        self.excerpts
5982            .first()
5983            .map(|excerpt| excerpt.buffer_snapshot(self))
5984            .map(|buffer| {
5985                language_settings(
5986                    buffer.language().map(|language| language.name()),
5987                    buffer.file(),
5988                    cx,
5989                )
5990            })
5991            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
5992    }
5993
5994    pub fn language_settings_at<'a, T: ToOffset>(
5995        &'a self,
5996        point: T,
5997        cx: &'a App,
5998    ) -> Cow<'a, LanguageSettings> {
5999        let mut language = None;
6000        let mut file = None;
6001        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6002            language = buffer.language_at(offset);
6003            file = buffer.file();
6004        }
6005        language_settings(language.map(|l| l.name()), file, cx)
6006    }
6007
6008    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6009        self.point_to_buffer_offset(point)
6010            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6011    }
6012
6013    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6014        self.point_to_buffer_offset(point)
6015            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6016            .unwrap_or_default()
6017    }
6018
6019    pub fn language_indent_size_at<T: ToOffset>(
6020        &self,
6021        position: T,
6022        cx: &App,
6023    ) -> Option<IndentSize> {
6024        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6025        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6026    }
6027
6028    pub fn is_dirty(&self) -> bool {
6029        self.is_dirty
6030    }
6031
6032    pub fn has_deleted_file(&self) -> bool {
6033        self.has_deleted_file
6034    }
6035
6036    pub fn has_conflict(&self) -> bool {
6037        self.has_conflict
6038    }
6039
6040    pub fn has_diagnostics(&self) -> bool {
6041        self.excerpts
6042            .iter()
6043            .any(|excerpt| excerpt.buffer_snapshot(self).has_diagnostics())
6044    }
6045
6046    pub fn diagnostic_group(
6047        &self,
6048        buffer_id: BufferId,
6049        group_id: usize,
6050    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6051        self.lift_buffer_metadata::<Point, _, _>(
6052            Point::zero()..self.max_point(),
6053            move |buffer, range| {
6054                if buffer.remote_id() != buffer_id {
6055                    return None;
6056                };
6057                Some(
6058                    buffer
6059                        .diagnostics_in_range(range, false)
6060                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6061                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6062                )
6063            },
6064        )
6065        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6066    }
6067
6068    pub fn diagnostics_in_range<'a, MBD>(
6069        &'a self,
6070        range: Range<MBD>,
6071    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6072    where
6073        MBD::TextDimension: 'a
6074            + text::ToOffset
6075            + text::FromAnchor
6076            + Sub<Output = MBD::TextDimension>
6077            + fmt::Debug
6078            + ops::Add<Output = MBD::TextDimension>
6079            + ops::AddAssign
6080            + Ord,
6081        MBD: MultiBufferDimension
6082            + Ord
6083            + Sub<Output = MBD::TextDimension>
6084            + ops::Add<MBD::TextDimension, Output = MBD>
6085            + ops::AddAssign<MBD::TextDimension>
6086            + 'a,
6087    {
6088        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6089            Some(
6090                buffer
6091                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6092                    .map(|entry| (entry.range, entry.diagnostic)),
6093            )
6094        })
6095        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6096    }
6097
6098    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6099        &'a self,
6100        range: Range<MBD>,
6101    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6102    where
6103        MBD: MultiBufferDimension
6104            + Ord
6105            + Sub<Output = MBD::TextDimension>
6106            + ops::Add<MBD::TextDimension, Output = MBD>
6107            + ops::AddAssign<MBD::TextDimension>,
6108        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6109            + ops::Add<Output = MBD::TextDimension>
6110            + text::ToOffset
6111            + text::FromAnchor
6112            + AddAssign<MBD::TextDimension>
6113            + Ord,
6114    {
6115        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6116            Some(
6117                buffer
6118                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6119                    .map(|entry| (entry.range, entry.diagnostic)),
6120            )
6121        })
6122        .map(|(range, diagnostic, excerpt)| {
6123            (
6124                excerpt.buffer_snapshot(self).remote_id(),
6125                DiagnosticEntryRef { diagnostic, range },
6126            )
6127        })
6128    }
6129
6130    pub fn syntax_ancestor<T: ToOffset>(
6131        &self,
6132        range: Range<T>,
6133    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6134        let range = range.start.to_offset(self)..range.end.to_offset(self);
6135        let mut excerpt = self.excerpt_containing(range.clone())?;
6136        let node = excerpt
6137            .buffer(self)
6138            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6139        let node_range = node.byte_range();
6140        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6141        if !excerpt.contains_buffer_range(node_range.clone(), self) {
6142            return None;
6143        };
6144        Some((node, excerpt.map_range_from_buffer(node_range)))
6145    }
6146
6147    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6148        let buffer = self.as_singleton()?;
6149        let outline = buffer.outline(theme);
6150        Some(Outline::new(
6151            outline
6152                .items
6153                .into_iter()
6154                .flat_map(|item| {
6155                    Some(OutlineItem {
6156                        depth: item.depth,
6157                        range: self.anchor_range_in_buffer(buffer.remote_id(), item.range)?,
6158                        source_range_for_text: self.anchor_range_in_buffer(
6159                            buffer.remote_id(),
6160                            item.source_range_for_text,
6161                        )?,
6162                        text: item.text,
6163                        highlight_ranges: item.highlight_ranges,
6164                        name_ranges: item.name_ranges,
6165                        body_range: item.body_range.and_then(|body_range| {
6166                            self.anchor_range_in_buffer(buffer.remote_id(), body_range)
6167                        }),
6168                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6169                            self.anchor_range_in_buffer(buffer.remote_id(), annotation_range)
6170                        }),
6171                    })
6172                })
6173                .collect(),
6174        ))
6175    }
6176
6177    pub fn symbols_containing<T: ToOffset>(
6178        &self,
6179        offset: T,
6180        theme: Option<&SyntaxTheme>,
6181    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6182        let anchor = self.anchor_before(offset);
6183        let target = anchor.try_seek_target(&self)?;
6184        let (_, _, excerpt) = self.excerpts.find((), &target, Bias::Left);
6185        let excerpt = excerpt?;
6186        let buffer_snapshot = excerpt.buffer_snapshot(self);
6187        Some((
6188            buffer_snapshot.remote_id(),
6189            buffer_snapshot
6190                .symbols_containing(
6191                    anchor
6192                        .excerpt_anchor()
6193                        .map(|anchor| anchor.text_anchor())
6194                        .unwrap_or(text::Anchor::min_for_buffer(buffer_snapshot.remote_id())),
6195                    theme,
6196                )
6197                .into_iter()
6198                .flat_map(|item| {
6199                    Some(OutlineItem {
6200                        depth: item.depth,
6201                        source_range_for_text: Anchor::range_in_buffer(
6202                            excerpt.path_key_index,
6203                            item.source_range_for_text,
6204                        ),
6205                        range: Anchor::range_in_buffer(excerpt.path_key_index, item.range),
6206                        text: item.text,
6207                        highlight_ranges: item.highlight_ranges,
6208                        name_ranges: item.name_ranges,
6209                        body_range: item.body_range.map(|body_range| {
6210                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6211                        }),
6212                        annotation_range: item.annotation_range.map(|body_range| {
6213                            Anchor::range_in_buffer(excerpt.path_key_index, body_range)
6214                        }),
6215                    })
6216                })
6217                .collect(),
6218        ))
6219    }
6220
6221    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6222        let (_, _, excerpt) = self
6223            .excerpts
6224            .find::<ExcerptSummary, _>((), path, Bias::Left);
6225        Some(excerpt?.buffer_snapshot(self))
6226    }
6227
6228    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6229        Some(&self.buffers.get(&buffer_id)?.path_key)
6230    }
6231
6232    pub fn path_key_index_for_buffer(&self, buffer_id: BufferId) -> Option<PathKeyIndex> {
6233        self.first_excerpt_for_buffer(buffer_id)
6234            .map(|excerpt| excerpt.path_key_index)
6235    }
6236
6237    pub fn first_excerpt_for_buffer(&self, buffer_id: BufferId) -> Option<&Excerpt> {
6238        let path_key = &self.buffers.get(&buffer_id)?.path_key;
6239        self.first_excerpt_for_path(path_key)
6240    }
6241
6242    pub fn first_excerpt_for_path(&self, path_key: &PathKey) -> Option<&Excerpt> {
6243        let (_, _, first_excerpt) =
6244            self.excerpts
6245                .find::<ExcerptSummary, _>((), path_key, Bias::Left);
6246        first_excerpt
6247    }
6248
6249    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6250        self.buffer_for_path(self.path_for_buffer(id)?)
6251    }
6252
6253    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6254        self.path_keys_by_index.get(&anchor.path).cloned()
6255    }
6256
6257    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6258        self.try_path_for_anchor(anchor)
6259            .expect("invalid anchor: path was never added to multibuffer")
6260    }
6261
6262    // todo!() this may not make sense any more
6263    pub fn range_for_excerpt(&self, excerpt_id: BufferId) -> Option<Range<Point>> {
6264        todo!()
6265        // let mut cursor = self
6266        //     .excerpts
6267        //     .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6268        // let locator = self.excerpt_locator_for_id(excerpt_id);
6269        // let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6270        // if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6271        //     sought_exact = true;
6272        //     cursor.prev();
6273        // } else if excerpt_id == ExcerptId::min() {
6274        //     sought_exact = true;
6275        // }
6276        // if sought_exact {
6277        //     let start = cursor.start().1;
6278        //     let end = cursor.end().1;
6279        //     let mut diff_transforms = self
6280        //         .diff_transforms
6281        //         .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6282        //     diff_transforms.seek(&start, Bias::Left);
6283        //     let overshoot = start - diff_transforms.start().0;
6284        //     let start = diff_transforms.start().1 + overshoot;
6285        //     diff_transforms.seek(&end, Bias::Right);
6286        //     let overshoot = end - diff_transforms.start().0;
6287        //     let end = diff_transforms.start().1 + overshoot;
6288        //     Some(start.0..end.0)
6289        // } else {
6290        //     None
6291        // }
6292    }
6293
6294    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6295    pub fn excerpt_containing<T: ToOffset>(
6296        &self,
6297        range: Range<T>,
6298    ) -> Option<MultiBufferExcerpt<'_>> {
6299        let range = range.start.to_offset(self)..range.end.to_offset(self);
6300        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6301        cursor.seek(&range.start);
6302
6303        let start_excerpt = cursor.excerpt()?;
6304        if range.end != range.start {
6305            cursor.seek_forward(&range.end);
6306            if cursor.excerpt()? != start_excerpt {
6307                return None;
6308            }
6309        }
6310
6311        cursor.seek_to_start_of_current_excerpt();
6312        let region = cursor.region()?;
6313        let offset = region.range.start;
6314        let buffer_offset = start_excerpt.buffer_start_offset(self);
6315        let excerpt_offset = *cursor.excerpts.start();
6316        Some(MultiBufferExcerpt {
6317            diff_transforms: cursor.diff_transforms,
6318            excerpt: start_excerpt,
6319            offset,
6320            buffer_offset,
6321            excerpt_offset,
6322        })
6323    }
6324
6325    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6326        match anchor {
6327            Anchor::Min => self.excerpts.first().map(|excerpt| excerpt.buffer_id),
6328            Anchor::Excerpt(excerpt_anchor) => Some(excerpt_anchor.text_anchor.buffer_id),
6329            Anchor::Max => self.excerpts.last().map(|excerpt| excerpt.buffer_id),
6330        }
6331    }
6332
6333    pub fn selections_in_range<'a>(
6334        &'a self,
6335        range: &'a Range<Anchor>,
6336        include_local: bool,
6337    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6338        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6339        cursor.seek(&range.start.seek_target(self), Bias::Left);
6340        cursor
6341            .take_while(move |excerpt| {
6342                let excerpt_start =
6343                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6344                excerpt_start.cmp(&range.end, self).is_le()
6345            })
6346            .flat_map(move |excerpt| {
6347                let buffer_snapshot = excerpt.buffer_snapshot(self);
6348                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6349                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6350                    && excerpt.contains(&excerpt_anchor, self)
6351                {
6352                    query_range.start = excerpt_anchor.text_anchor();
6353                }
6354                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6355                    && excerpt.contains(&excerpt_anchor, self)
6356                {
6357                    query_range.end = excerpt_anchor.text_anchor();
6358                }
6359
6360                buffer_snapshot
6361                    .selections_in_range(query_range, include_local)
6362                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6363                        selections.map(move |selection| {
6364                            let mut start =
6365                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6366                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6367                            if range.start.cmp(&start, self).is_gt() {
6368                                start = range.start;
6369                            }
6370                            if range.end.cmp(&end, self).is_lt() {
6371                                end = range.end;
6372                            }
6373
6374                            (
6375                                replica_id,
6376                                line_mode,
6377                                cursor_shape,
6378                                Selection {
6379                                    id: selection.id,
6380                                    start,
6381                                    end,
6382                                    reversed: selection.reversed,
6383                                    goal: selection.goal,
6384                                },
6385                            )
6386                        })
6387                    })
6388            })
6389    }
6390
6391    pub fn show_headers(&self) -> bool {
6392        self.show_headers
6393    }
6394
6395    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6396        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6397    }
6398
6399    pub fn all_diff_hunks_expanded(&self) -> bool {
6400        self.all_diff_hunks_expanded
6401    }
6402
6403    /// Visually annotates a position or range with the `Debug` representation of a value. The
6404    /// callsite of this function is used as a key - previous annotations will be removed.
6405    #[cfg(debug_assertions)]
6406    #[track_caller]
6407    pub fn debug<V, R>(&self, ranges: &R, value: V)
6408    where
6409        R: debug::ToMultiBufferDebugRanges,
6410        V: std::fmt::Debug,
6411    {
6412        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6413    }
6414
6415    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6416    /// debug annotations with the same key will be removed. The key is also used to determine the
6417    /// annotation's color.
6418    #[cfg(debug_assertions)]
6419    #[track_caller]
6420    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6421    where
6422        K: std::hash::Hash + 'static,
6423        R: debug::ToMultiBufferDebugRanges,
6424        V: std::fmt::Debug,
6425    {
6426        let text_ranges = ranges
6427            .to_multi_buffer_debug_ranges(self)
6428            .into_iter()
6429            .flat_map(|range| {
6430                self.range_to_buffer_ranges(range)
6431                    .into_iter()
6432                    .map(|(buffer, range)| {
6433                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6434                    })
6435            })
6436            .collect();
6437        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6438            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6439        });
6440    }
6441
6442    fn excerpt_edits_for_diff_change(
6443        &self,
6444        path: &PathKey,
6445        diff_change_range: Range<usize>,
6446    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6447        let mut excerpt_edits = Vec::new();
6448        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6449        cursor.seek(path, Bias::Left);
6450        while let Some(excerpt) = cursor.item()
6451            && &excerpt.path_key == path
6452        {
6453            let buffer_snapshot = excerpt.buffer_snapshot(self);
6454            let excerpt_buffer_range = excerpt.range.context.to_offset(buffer_snapshot);
6455            let excerpt_start = cursor.start().clone();
6456            let excerpt_len = excerpt.text_summary.len;
6457            cursor.next();
6458            if diff_change_range.end < excerpt_buffer_range.start
6459                || diff_change_range.start > excerpt_buffer_range.end
6460            {
6461                continue;
6462            }
6463            let diff_change_start_in_excerpt = diff_change_range
6464                .start
6465                .saturating_sub(excerpt_buffer_range.start);
6466            let diff_change_end_in_excerpt = diff_change_range
6467                .end
6468                .saturating_sub(excerpt_buffer_range.start);
6469            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6470            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6471            excerpt_edits.push(Edit {
6472                old: edit_start..edit_end,
6473                new: edit_start..edit_end,
6474            });
6475        }
6476        excerpt_edits
6477    }
6478
6479    fn excerpts_for_path<'a>(
6480        &'a self,
6481        path_key: &'a PathKey,
6482    ) -> impl Iterator<Item = ExcerptInfo> + 'a {
6483        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6484        cursor.seek(path_key, Bias::Left);
6485        cursor
6486            .take_while(move |item| &item.path_key == path_key)
6487            .map(|excerpt| excerpt.info())
6488    }
6489}
6490
6491#[cfg(any(test, feature = "test-support"))]
6492impl MultiBufferSnapshot {
6493    pub fn random_byte_range(
6494        &self,
6495        start_offset: MultiBufferOffset,
6496        rng: &mut impl rand::Rng,
6497    ) -> Range<MultiBufferOffset> {
6498        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6499        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6500        start..end
6501    }
6502
6503    #[cfg(any(test, feature = "test-support"))]
6504    fn check_invariants(&self) {
6505        let excerpts = self.excerpts.items(());
6506
6507        let all_buffer_path_keys =
6508            HashSet::from_iter(self.buffers.values().map(|b| b.path_key.clone()));
6509        let all_excerpt_path_keys = HashSet::from_iter(excerpts.iter().map(|e| e.path_key.clone()));
6510
6511        for (ix, excerpt) in excerpts.iter().enumerate() {
6512            if ix > 0 {
6513                let prev = &excerpts[ix - 1];
6514
6515                if excerpt.path_key < prev.path_key {
6516                    panic!("excerpt path_keys are out-of-order: {:#?}", excerpts);
6517                } else if excerpt.path_key == prev.path_key {
6518                    if excerpt
6519                        .start_anchor()
6520                        .cmp(&prev.end_anchor(), &self)
6521                        .is_le()
6522                    {
6523                        panic!("excerpt anchors are out-of-order: {:#?}", excerpts);
6524                    }
6525                    if excerpt
6526                        .start_anchor()
6527                        .cmp(&excerpt.end_anchor(), &self)
6528                        .is_ge()
6529                    {
6530                        panic!("excerpt with backward range: {:#?}", excerpts);
6531                    }
6532                }
6533            }
6534
6535            if ix < excerpts.len() - 1 {
6536                assert!(
6537                    excerpt.has_trailing_newline,
6538                    "non-trailing excerpt has no trailing newline: {:#?}",
6539                    excerpts
6540                );
6541            } else {
6542                assert!(
6543                    !excerpt.has_trailing_newline,
6544                    "trailing excerpt has trailing newline: {:#?}",
6545                    excerpts
6546                );
6547            }
6548            assert!(
6549                all_buffer_path_keys.contains(&excerpt.path_key),
6550                "excerpt path key not found in active path keys: {:#?}",
6551                excerpt.path_key
6552            );
6553            assert_eq!(
6554                self.path_keys_by_index.get(&excerpt.path_key_index),
6555                Some(&excerpt.path_key),
6556                "excerpt path key index does not match path key: {:#?}",
6557                excerpt.path_key,
6558            );
6559        }
6560        assert_eq!(all_buffer_path_keys, all_excerpt_path_keys);
6561
6562        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6563            panic!(
6564                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6565                self.excerpts.summary().text,
6566                self.diff_transforms.summary().input,
6567                self.diff_transforms.items(()),
6568            );
6569        }
6570
6571        let mut prev_transform: Option<&DiffTransform> = None;
6572        for item in self.diff_transforms.iter() {
6573            if let DiffTransform::BufferContent {
6574                summary,
6575                inserted_hunk_info,
6576            } = item
6577            {
6578                if let Some(DiffTransform::BufferContent {
6579                    inserted_hunk_info: prev_inserted_hunk_info,
6580                    ..
6581                }) = prev_transform
6582                    && *inserted_hunk_info == *prev_inserted_hunk_info
6583                {
6584                    panic!(
6585                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6586                        self.diff_transforms.items(())
6587                    );
6588                }
6589                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6590                    panic!("empty buffer content transform");
6591                }
6592            }
6593            prev_transform = Some(item);
6594        }
6595    }
6596}
6597
6598impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6599where
6600    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6601    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6602{
6603    #[instrument(skip_all)]
6604    fn seek(&mut self, position: &MBD) {
6605        let position = OutputDimension(*position);
6606        self.cached_region.take();
6607        self.diff_transforms.seek(&position, Bias::Right);
6608        if self.diff_transforms.item().is_none()
6609            && self.diff_transforms.start().output_dimension == position
6610        {
6611            self.diff_transforms.prev();
6612        }
6613
6614        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6615        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6616            let overshoot = position - self.diff_transforms.start().output_dimension;
6617            excerpt_position += overshoot;
6618        }
6619
6620        self.excerpts.seek(&excerpt_position, Bias::Right);
6621        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6622            self.excerpts.prev();
6623        }
6624    }
6625
6626    fn seek_forward(&mut self, position: &MBD) {
6627        let position = OutputDimension(*position);
6628        self.cached_region.take();
6629        self.diff_transforms.seek_forward(&position, Bias::Right);
6630        if self.diff_transforms.item().is_none()
6631            && self.diff_transforms.start().output_dimension == position
6632        {
6633            self.diff_transforms.prev();
6634        }
6635
6636        let overshoot = position - self.diff_transforms.start().output_dimension;
6637        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6638        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6639            excerpt_position += overshoot;
6640        }
6641
6642        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6643        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6644            self.excerpts.prev();
6645        }
6646    }
6647
6648    fn next_excerpt(&mut self) {
6649        self.excerpts.next();
6650        self.seek_to_start_of_current_excerpt();
6651    }
6652
6653    fn prev_excerpt(&mut self) {
6654        self.excerpts.prev();
6655        self.seek_to_start_of_current_excerpt();
6656    }
6657
6658    fn seek_to_start_of_current_excerpt(&mut self) {
6659        self.cached_region.take();
6660
6661        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6662            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6663            && self.diff_transforms.next_item().is_some()
6664        {
6665            self.diff_transforms.next();
6666        }
6667    }
6668
6669    fn next_excerpt_forwards(&mut self) {
6670        self.excerpts.next();
6671        self.seek_to_start_of_current_excerpt_forward();
6672    }
6673
6674    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6675        self.cached_region.take();
6676
6677        if self
6678            .diff_transforms
6679            .seek_forward(self.excerpts.start(), Bias::Left)
6680            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6681            && self.diff_transforms.next_item().is_some()
6682        {
6683            self.diff_transforms.next();
6684        }
6685    }
6686
6687    fn next(&mut self) {
6688        self.cached_region.take();
6689        match self
6690            .diff_transforms
6691            .end()
6692            .excerpt_dimension
6693            .cmp(&self.excerpts.end())
6694        {
6695            cmp::Ordering::Less => self.diff_transforms.next(),
6696            cmp::Ordering::Greater => self.excerpts.next(),
6697            cmp::Ordering::Equal => {
6698                self.diff_transforms.next();
6699                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6700                    || self.diff_transforms.item().is_none()
6701                {
6702                    self.excerpts.next();
6703                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6704                    self.diff_transforms.item()
6705                    && self
6706                        .excerpts
6707                        .item()
6708                        .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end)
6709                {
6710                    self.excerpts.next();
6711                }
6712            }
6713        }
6714    }
6715
6716    fn prev(&mut self) {
6717        self.cached_region.take();
6718        match self
6719            .diff_transforms
6720            .start()
6721            .excerpt_dimension
6722            .cmp(self.excerpts.start())
6723        {
6724            cmp::Ordering::Less => self.excerpts.prev(),
6725            cmp::Ordering::Greater => self.diff_transforms.prev(),
6726            cmp::Ordering::Equal => {
6727                self.diff_transforms.prev();
6728                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6729                    || self.diff_transforms.item().is_none()
6730                {
6731                    self.excerpts.prev();
6732                }
6733            }
6734        }
6735    }
6736
6737    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
6738        self.cached_region
6739            .get_or_init(|| self.build_region())
6740            .as_ref()
6741    }
6742
6743    fn is_at_start_of_excerpt(&mut self) -> bool {
6744        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6745            return false;
6746        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6747            return true;
6748        }
6749
6750        self.diff_transforms.prev();
6751        let prev_transform = self.diff_transforms.item();
6752        self.diff_transforms.next();
6753
6754        prev_transform.is_none_or(|next_transform| {
6755            matches!(next_transform, DiffTransform::BufferContent { .. })
6756        })
6757    }
6758
6759    fn is_at_end_of_excerpt(&self) -> bool {
6760        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6761            return false;
6762        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6763            || self.diff_transforms.item().is_none()
6764        {
6765            return true;
6766        }
6767
6768        let next_transform = self.diff_transforms.next_item();
6769        next_transform.is_none_or(|next_transform| match next_transform {
6770            DiffTransform::BufferContent { .. } => true,
6771            DiffTransform::DeletedHunk { hunk_info, .. } => self
6772                .excerpts
6773                .item()
6774                .is_some_and(|excerpt| excerpt.end_anchor() != hunk_info.excerpt_end),
6775        })
6776    }
6777
6778    fn main_buffer_position(&self) -> Option<BD> {
6779        let excerpt = self.excerpts.item()?;
6780        let buffer = excerpt.buffer_snapshot(self.snapshot);
6781        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6782        let mut buffer_start = buffer_context_start;
6783        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6784        buffer_start += overshoot;
6785        Some(buffer_start)
6786    }
6787
6788    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6789        let excerpt = self.excerpts.item()?;
6790        match self.diff_transforms.item()? {
6791            DiffTransform::DeletedHunk {
6792                buffer_id,
6793                base_text_byte_range,
6794                has_trailing_newline,
6795                hunk_info,
6796                ..
6797            } => {
6798                let diff = self.snapshot.diffs.get(buffer_id)?;
6799                let buffer = diff.base_text();
6800                let mut rope_cursor = buffer.as_rope().cursor(0);
6801                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6802                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6803                let mut buffer_end = buffer_start;
6804                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6805                let start = self.diff_transforms.start().output_dimension.0;
6806                let end = self.diff_transforms.end().output_dimension.0;
6807                Some(MultiBufferRegion {
6808                    buffer,
6809                    excerpt,
6810                    has_trailing_newline: *has_trailing_newline,
6811                    is_main_buffer: false,
6812                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6813                        hunk_info.hunk_secondary_status,
6814                    )),
6815                    buffer_range: buffer_start..buffer_end,
6816                    range: start..end,
6817                })
6818            }
6819            DiffTransform::BufferContent {
6820                inserted_hunk_info, ..
6821            } => {
6822                let buffer = excerpt.buffer_snapshot(self.snapshot);
6823                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6824
6825                let mut start = self.diff_transforms.start().output_dimension.0;
6826                let mut buffer_start = buffer_context_start;
6827                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6828                    let overshoot =
6829                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6830                    start += overshoot;
6831                } else {
6832                    let overshoot =
6833                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6834                    buffer_start += overshoot;
6835                }
6836
6837                let mut end;
6838                let mut buffer_end;
6839                let has_trailing_newline;
6840                let transform_end = self.diff_transforms.end();
6841                if transform_end.excerpt_dimension < self.excerpts.end() {
6842                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
6843                    end = transform_end.output_dimension.0;
6844                    buffer_end = buffer_context_start;
6845                    buffer_end += overshoot;
6846                    has_trailing_newline = false;
6847                } else {
6848                    let overshoot =
6849                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6850                    end = self.diff_transforms.start().output_dimension.0;
6851                    end += overshoot;
6852                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6853                    has_trailing_newline = excerpt.has_trailing_newline;
6854                };
6855
6856                let diff_hunk_status = inserted_hunk_info.map(|info| {
6857                    if info.is_logically_deleted {
6858                        DiffHunkStatus::deleted(info.hunk_secondary_status)
6859                    } else {
6860                        DiffHunkStatus::added(info.hunk_secondary_status)
6861                    }
6862                });
6863
6864                Some(MultiBufferRegion {
6865                    buffer,
6866                    excerpt,
6867                    has_trailing_newline,
6868                    is_main_buffer: true,
6869                    diff_hunk_status,
6870                    buffer_range: buffer_start..buffer_end,
6871                    range: start..end,
6872                })
6873            }
6874        }
6875    }
6876
6877    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
6878        let excerpt = self.excerpts.item()?;
6879        match self.diff_transforms.item()? {
6880            &DiffTransform::DeletedHunk { .. } => {
6881                let start = self.diff_transforms.start().output_dimension.0;
6882                let end = self.diff_transforms.end().output_dimension.0;
6883                Some((excerpt, start..end))
6884            }
6885            DiffTransform::BufferContent { .. } => {
6886                let mut start = self.diff_transforms.start().output_dimension.0;
6887                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6888                    let overshoot =
6889                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6890                    start += overshoot;
6891                }
6892
6893                let mut end;
6894                let transform_end = self.diff_transforms.end();
6895                if transform_end.excerpt_dimension < self.excerpts.end() {
6896                    end = transform_end.output_dimension.0;
6897                } else {
6898                    let overshoot =
6899                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6900                    end = self.diff_transforms.start().output_dimension.0;
6901                    end += overshoot;
6902                };
6903
6904                Some((excerpt, start..end))
6905            }
6906        }
6907    }
6908
6909    fn excerpt(&self) -> Option<&'a Excerpt> {
6910        self.excerpts.item()
6911    }
6912}
6913
6914impl Excerpt {
6915    fn new(
6916        path_key: PathKey,
6917        path_key_index: PathKeyIndex,
6918        buffer_snapshot: &BufferSnapshot,
6919        range: ExcerptRange<text::Anchor>,
6920        has_trailing_newline: bool,
6921    ) -> Self {
6922        Excerpt {
6923            path_key,
6924            path_key_index,
6925            buffer_id: buffer_snapshot.remote_id(),
6926            max_buffer_row: range.context.end.to_point(&buffer_snapshot).row,
6927            text_summary: buffer_snapshot.text_summary_for_range::<TextSummary, _>(
6928                range.context.to_offset(&buffer_snapshot),
6929            ),
6930            range,
6931            has_trailing_newline,
6932        }
6933    }
6934
6935    fn buffer_snapshot<'a>(&self, snapshot: &'a MultiBufferSnapshot) -> &'a BufferSnapshot {
6936        &snapshot
6937            .buffers
6938            .get(&self.buffer_id)
6939            .expect("buffer snapshot not found for excerpt")
6940            .buffer_snapshot
6941    }
6942
6943    fn buffer(&self, multibuffer: &MultiBuffer) -> Entity<Buffer> {
6944        multibuffer
6945            .buffer(self.buffer_id)
6946            .expect("buffer entity not found for excerpt")
6947    }
6948
6949    fn info(&self) -> ExcerptInfo {
6950        ExcerptInfo {
6951            path_key_index: self.path_key_index,
6952            buffer_id: self.buffer_id,
6953            range: self.range.context.clone(),
6954        }
6955    }
6956
6957    fn chunks_in_range<'a>(
6958        &'a self,
6959        range: Range<usize>,
6960        language_aware: bool,
6961        snapshot: &'a MultiBufferSnapshot,
6962    ) -> ExcerptChunks<'a> {
6963        let buffer = self.buffer_snapshot(snapshot);
6964        let content_start = self.range.context.start.to_offset(buffer);
6965        let chunks_start = content_start + range.start;
6966        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6967
6968        let has_footer = self.has_trailing_newline
6969            && range.start <= self.text_summary.len
6970            && range.end > self.text_summary.len;
6971
6972        let content_chunks = buffer.chunks(chunks_start..chunks_end, language_aware);
6973
6974        ExcerptChunks {
6975            content_chunks,
6976            has_footer,
6977            end: self.end_anchor(),
6978        }
6979    }
6980
6981    fn seek_chunks(
6982        &self,
6983        excerpt_chunks: &mut ExcerptChunks,
6984        range: Range<usize>,
6985        snapshot: &MultiBufferSnapshot,
6986    ) {
6987        let buffer = self.buffer_snapshot(snapshot);
6988        let content_start = self.range.context.start.to_offset(buffer);
6989        let chunks_start = content_start + range.start;
6990        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6991        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6992        excerpt_chunks.has_footer = self.has_trailing_newline
6993            && range.start <= self.text_summary.len
6994            && range.end > self.text_summary.len;
6995    }
6996
6997    fn clip_anchor(
6998        &self,
6999        text_anchor: text::Anchor,
7000        snapshot: &MultiBufferSnapshot,
7001    ) -> text::Anchor {
7002        let buffer = self.buffer_snapshot(snapshot);
7003        if text_anchor.cmp(&self.range.context.start, buffer).is_lt() {
7004            self.range.context.start
7005        } else if text_anchor.cmp(&self.range.context.end, buffer).is_gt() {
7006            self.range.context.end
7007        } else {
7008            text_anchor
7009        }
7010    }
7011
7012    pub(crate) fn contains(&self, anchor: &ExcerptAnchor, snapshot: &MultiBufferSnapshot) -> bool {
7013        self.path_key_index == anchor.path
7014            && self.buffer_id == anchor.text_anchor.buffer_id
7015            && self
7016                .range
7017                .contains(&anchor.text_anchor(), self.buffer_snapshot(snapshot))
7018    }
7019
7020    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7021    fn buffer_start_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7022        BufferOffset(
7023            self.range
7024                .context
7025                .start
7026                .to_offset(self.buffer_snapshot(snapshot)),
7027        )
7028    }
7029
7030    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7031    fn buffer_end_offset(&self, snapshot: &MultiBufferSnapshot) -> BufferOffset {
7032        self.buffer_start_offset(snapshot) + self.text_summary.len
7033    }
7034
7035    fn start_anchor(&self) -> ExcerptAnchor {
7036        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.start)
7037    }
7038
7039    fn end_anchor(&self) -> ExcerptAnchor {
7040        ExcerptAnchor::in_buffer(self.path_key_index, self.range.context.end)
7041    }
7042}
7043
7044impl PartialEq for Excerpt {
7045    fn eq(&self, other: &Self) -> bool {
7046        self.path_key_index == other.path_key_index
7047            && self.buffer_id == other.buffer_id
7048            && self.range.context == other.range.context
7049    }
7050}
7051
7052impl<'a> MultiBufferExcerpt<'a> {
7053    pub fn buffer_id(&self) -> BufferId {
7054        self.excerpt.buffer_id
7055    }
7056
7057    pub fn start_anchor(&self) -> Anchor {
7058        Anchor::in_buffer(
7059            self.excerpt.path_key_index,
7060            self.excerpt.range.context.start,
7061        )
7062    }
7063
7064    pub fn end_anchor(&self) -> Anchor {
7065        Anchor::in_buffer(self.excerpt.path_key_index, self.excerpt.range.context.end)
7066    }
7067
7068    pub fn buffer<'b>(&self, snapshot: &'b MultiBufferSnapshot) -> &'b BufferSnapshot {
7069        self.excerpt.buffer_snapshot(snapshot)
7070    }
7071
7072    pub fn buffer_range(&self, snapshot: &'a MultiBufferSnapshot) -> Range<BufferOffset> {
7073        self.buffer_offset
7074            ..BufferOffset(
7075                self.excerpt
7076                    .range
7077                    .context
7078                    .end
7079                    .to_offset(&self.excerpt.buffer_snapshot(snapshot).text),
7080            )
7081    }
7082
7083    pub fn start_offset(&self) -> MultiBufferOffset {
7084        self.offset
7085    }
7086
7087    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7088    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7089        self.map_range_to_buffer(offset..offset).start
7090    }
7091
7092    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7093    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7094        self.diff_transforms
7095            .seek(&OutputDimension(range.start), Bias::Right);
7096        let start = self.map_offset_to_buffer_internal(range.start);
7097        let end = if range.end > range.start {
7098            self.diff_transforms
7099                .seek_forward(&OutputDimension(range.end), Bias::Right);
7100            self.map_offset_to_buffer_internal(range.end)
7101        } else {
7102            start
7103        };
7104        start..end
7105    }
7106
7107    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7108        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7109        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7110            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7111        };
7112        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7113        self.buffer_offset + offset_in_excerpt
7114    }
7115
7116    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7117    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7118        self.map_range_from_buffer(buffer_offset..buffer_offset)
7119            .start
7120    }
7121
7122    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7123    pub fn map_range_from_buffer(
7124        &mut self,
7125        buffer_range: Range<BufferOffset>,
7126    ) -> Range<MultiBufferOffset> {
7127        if buffer_range.start < self.buffer_offset {
7128            log::warn!(
7129                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7130            );
7131            return self.offset..self.offset;
7132        }
7133        let overshoot = buffer_range.start - self.buffer_offset;
7134        let excerpt_offset = self.excerpt_offset + overshoot;
7135        let excerpt_seek_dim = excerpt_offset;
7136        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7137        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7138            log::warn!(
7139                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7140            );
7141            return self.offset..self.offset;
7142        }
7143        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7144        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7145
7146        let end = if buffer_range.start < buffer_range.end {
7147            let overshoot = buffer_range.end - self.buffer_offset;
7148            let excerpt_offset = self.excerpt_offset + overshoot;
7149            let excerpt_seek_dim = excerpt_offset;
7150            self.diff_transforms
7151                .seek_forward(&excerpt_seek_dim, Bias::Right);
7152            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7153            // todo(lw): Clamp end to the excerpt boundaries
7154            self.diff_transforms.start().output_dimension.0 + overshoot
7155        } else {
7156            start
7157        };
7158
7159        start..end
7160    }
7161
7162    /// Returns true if the entirety of the given range is in the buffer's excerpt
7163    pub fn contains_buffer_range(
7164        &self,
7165        range: Range<BufferOffset>,
7166        snapshot: &MultiBufferSnapshot,
7167    ) -> bool {
7168        range.start >= self.excerpt.buffer_start_offset(snapshot)
7169            && range.end <= self.excerpt.buffer_end_offset(snapshot)
7170    }
7171
7172    /// Returns true if any part of the given range is in the buffer's excerpt
7173    pub fn contains_partial_buffer_range(
7174        &self,
7175        range: Range<BufferOffset>,
7176        snapshot: &MultiBufferSnapshot,
7177    ) -> bool {
7178        range.start <= self.excerpt.buffer_end_offset(snapshot)
7179            && range.end >= self.excerpt.buffer_start_offset(snapshot)
7180    }
7181
7182    pub fn max_buffer_row(&self) -> u32 {
7183        self.excerpt.max_buffer_row
7184    }
7185}
7186
7187impl fmt::Debug for Excerpt {
7188    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7189        f.debug_struct("Excerpt")
7190            .field("path_key", &self.path_key)
7191            .field("range", &self.range)
7192            .field("text_summary", &self.text_summary)
7193            .field("has_trailing_newline", &self.has_trailing_newline)
7194            .finish()
7195    }
7196}
7197
7198impl sum_tree::Item for Excerpt {
7199    type Summary = ExcerptSummary;
7200
7201    fn summary(&self, _cx: ()) -> Self::Summary {
7202        let mut text = self.text_summary;
7203        if self.has_trailing_newline {
7204            text += TextSummary::from("\n");
7205        }
7206        ExcerptSummary {
7207            path_key: self.path_key.clone(),
7208            max_anchor: Some(self.range.context.end),
7209            widest_line_number: self.max_buffer_row,
7210            text: text.into(),
7211            count: 1,
7212        }
7213    }
7214}
7215
7216impl DiffTransform {
7217    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7218        match self {
7219            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7220            DiffTransform::BufferContent {
7221                inserted_hunk_info, ..
7222            } => *inserted_hunk_info,
7223        }
7224    }
7225}
7226
7227impl sum_tree::Item for DiffTransform {
7228    type Summary = DiffTransformSummary;
7229
7230    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7231        match self {
7232            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7233                input: *summary,
7234                output: *summary,
7235            },
7236            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7237                input: MBTextSummary::default(),
7238                output: summary.into(),
7239            },
7240        }
7241    }
7242}
7243
7244impl DiffTransformSummary {
7245    fn excerpt_len(&self) -> ExcerptOffset {
7246        ExcerptDimension(self.input.len)
7247    }
7248}
7249
7250impl sum_tree::ContextLessSummary for DiffTransformSummary {
7251    fn zero() -> Self {
7252        DiffTransformSummary {
7253            input: MBTextSummary::default(),
7254            output: MBTextSummary::default(),
7255        }
7256    }
7257
7258    fn add_summary(&mut self, other: &Self) {
7259        self.input += other.input;
7260        self.output += other.output;
7261    }
7262}
7263
7264impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7265    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7266        PathKey::min()
7267    }
7268
7269    fn add_summary(
7270        &mut self,
7271        summary: &'_ ExcerptSummary,
7272        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7273    ) {
7274        *self = summary.path_key.clone();
7275    }
7276}
7277
7278impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7279    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7280        MultiBufferOffset::ZERO
7281    }
7282
7283    fn add_summary(
7284        &mut self,
7285        summary: &'_ ExcerptSummary,
7286        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7287    ) {
7288        *self += summary.text.len
7289    }
7290}
7291
7292impl sum_tree::ContextLessSummary for ExcerptSummary {
7293    fn zero() -> Self {
7294        Self::min()
7295    }
7296
7297    fn add_summary(&mut self, summary: &Self) {
7298        debug_assert!(
7299            summary.path_key >= self.path_key,
7300            "Path keys must be in ascending order: {:?} > {:?}",
7301            summary.path_key,
7302            self.path_key
7303        );
7304
7305        self.path_key = summary.path_key.clone();
7306        self.max_anchor = summary.max_anchor;
7307        self.text += summary.text;
7308        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7309        self.count += summary.count;
7310    }
7311}
7312
7313impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7314    fn cmp(
7315        &self,
7316        cursor_location: &ExcerptSummary,
7317        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7318    ) -> cmp::Ordering {
7319        match self {
7320            AnchorSeekTarget::Min => Ordering::Less,
7321            AnchorSeekTarget::Max => Ordering::Greater,
7322            AnchorSeekTarget::Excerpt {
7323                path_key,
7324                anchor,
7325                snapshot,
7326            } => {
7327                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7328                if path_comparison.is_ne() {
7329                    path_comparison
7330                } else if let Some(snapshot) = snapshot {
7331                    // todo!() think more about this..
7332                    // the goal is that if you seek to buffer_id 1 (path key a)
7333                    // and you find that path key a now belongs to buffer_id 2,
7334                    // we'll seek past buffer_id 2.
7335                    if cursor_location.max_anchor.map(|a| a.buffer_id) != Some(snapshot.remote_id())
7336                    {
7337                        Ordering::Greater
7338                    } else {
7339                        anchor
7340                            .text_anchor()
7341                            .cmp(&cursor_location.max_anchor.unwrap(), snapshot)
7342                    }
7343                } else {
7344                    // shouldn't happen because we expect this buffer not to have any excerpts
7345                    // (otherwise snapshot would have been Some)
7346                    Ordering::Equal
7347                }
7348            }
7349        }
7350    }
7351}
7352
7353impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7354    fn cmp(
7355        &self,
7356        cursor_location: &ExcerptSummary,
7357        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7358    ) -> cmp::Ordering {
7359        Ord::cmp(self, &cursor_location.path_key)
7360    }
7361}
7362
7363impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7364where
7365    MBD: MultiBufferDimension + Default,
7366{
7367    fn zero(_: ()) -> Self {
7368        ExcerptDimension(MBD::default())
7369    }
7370
7371    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7372        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7373    }
7374}
7375
7376#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7377struct OutputDimension<T>(T);
7378
7379impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7380    fn eq(&self, other: &T) -> bool {
7381        self.0 == *other
7382    }
7383}
7384
7385impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7386    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7387        self.0.partial_cmp(other)
7388    }
7389}
7390
7391impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7392where
7393    T: ops::Sub<U, Output = R>,
7394{
7395    type Output = R;
7396
7397    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7398        self.0 - other.0
7399    }
7400}
7401
7402impl<R, T, U> ops::Add<U> for OutputDimension<T>
7403where
7404    T: ops::Add<U, Output = R>,
7405{
7406    type Output = OutputDimension<R>;
7407
7408    fn add(self, other: U) -> Self::Output {
7409        OutputDimension(self.0 + other)
7410    }
7411}
7412
7413impl<T, U> AddAssign<U> for OutputDimension<T>
7414where
7415    T: AddAssign<U>,
7416{
7417    fn add_assign(&mut self, other: U) {
7418        self.0 += other;
7419    }
7420}
7421
7422impl<T, U> SubAssign<U> for OutputDimension<T>
7423where
7424    T: SubAssign<U>,
7425{
7426    fn sub_assign(&mut self, other: U) {
7427        self.0 -= other;
7428    }
7429}
7430
7431#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7432struct ExcerptDimension<T>(T);
7433
7434impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7435    fn eq(&self, other: &T) -> bool {
7436        self.0 == *other
7437    }
7438}
7439
7440impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7441    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7442        self.0.partial_cmp(other)
7443    }
7444}
7445
7446impl ExcerptOffset {
7447    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7448        self.0.saturating_sub(other.0)
7449    }
7450}
7451
7452impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7453where
7454    T: ops::Sub<U, Output = R>,
7455{
7456    type Output = R;
7457
7458    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7459        self.0 - other.0
7460    }
7461}
7462
7463impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7464where
7465    T: ops::Add<U, Output = R>,
7466{
7467    type Output = ExcerptDimension<R>;
7468
7469    fn add(self, other: U) -> Self::Output {
7470        ExcerptDimension(self.0 + other)
7471    }
7472}
7473
7474impl<T, U> AddAssign<U> for ExcerptDimension<T>
7475where
7476    T: AddAssign<U>,
7477{
7478    fn add_assign(&mut self, other: U) {
7479        self.0 += other;
7480    }
7481}
7482
7483impl<T, U> SubAssign<U> for ExcerptDimension<T>
7484where
7485    T: SubAssign<U>,
7486{
7487    fn sub_assign(&mut self, other: U) {
7488        self.0 -= other;
7489    }
7490}
7491
7492impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7493    fn zero(_: ()) -> Self {
7494        MultiBufferOffset::ZERO
7495    }
7496
7497    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7498        *self += summary.output.len;
7499    }
7500}
7501
7502impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7503    for ExcerptDimension<MBD>
7504where
7505    MBD: MultiBufferDimension + Ord,
7506{
7507    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7508        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7509    }
7510}
7511
7512impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7513    for ExcerptDimension<MBD>
7514where
7515    MBD: MultiBufferDimension + Ord,
7516{
7517    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7518        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7519    }
7520}
7521
7522impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7523    for ExcerptDimension<MBD>
7524{
7525    fn zero(_: ()) -> Self {
7526        ExcerptDimension(MBD::default())
7527    }
7528
7529    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7530        self.0.add_mb_text_summary(&summary.input)
7531    }
7532}
7533
7534impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7535    for OutputDimension<MBD>
7536where
7537    MBD: MultiBufferDimension + Ord,
7538{
7539    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7540        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7541    }
7542}
7543
7544impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7545    for OutputDimension<MBD>
7546{
7547    fn zero(_: ()) -> Self {
7548        OutputDimension(MBD::default())
7549    }
7550
7551    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7552        self.0.add_mb_text_summary(&summary.output)
7553    }
7554}
7555
7556impl MultiBufferRows<'_> {
7557    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7558        self.point = Point::new(row, 0);
7559        self.cursor.seek(&self.point);
7560    }
7561}
7562
7563impl Iterator for MultiBufferRows<'_> {
7564    type Item = RowInfo;
7565
7566    fn next(&mut self) -> Option<Self::Item> {
7567        if self.is_empty && self.point.row == 0 {
7568            self.point += Point::new(1, 0);
7569            return Some(RowInfo {
7570                buffer_id: None,
7571                buffer_row: Some(0),
7572                multibuffer_row: Some(MultiBufferRow(0)),
7573                diff_status: None,
7574                expand_info: None,
7575                wrapped_buffer_row: None,
7576            });
7577        }
7578
7579        let mut region = self.cursor.region()?.clone();
7580        while self.point >= region.range.end {
7581            self.cursor.next();
7582            if let Some(next_region) = self.cursor.region() {
7583                region = next_region.clone();
7584            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7585                let multibuffer_row = MultiBufferRow(self.point.row);
7586                let last_excerpt = self
7587                    .cursor
7588                    .excerpts
7589                    .item()
7590                    .or(self.cursor.excerpts.prev_item())?;
7591                let buffer_snapshot = last_excerpt.buffer_snapshot(self.cursor.snapshot);
7592                let last_row = last_excerpt.range.context.end.to_point(buffer_snapshot).row;
7593
7594                let first_row = last_excerpt
7595                    .range
7596                    .context
7597                    .start
7598                    .to_point(buffer_snapshot)
7599                    .row;
7600
7601                let expand_info = if self.is_singleton {
7602                    None
7603                } else {
7604                    let needs_expand_up = first_row == last_row
7605                        && last_row > 0
7606                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7607                    let needs_expand_down = last_row < buffer_snapshot.max_point().row;
7608
7609                    if needs_expand_up && needs_expand_down {
7610                        Some(ExpandExcerptDirection::UpAndDown)
7611                    } else if needs_expand_up {
7612                        Some(ExpandExcerptDirection::Up)
7613                    } else if needs_expand_down {
7614                        Some(ExpandExcerptDirection::Down)
7615                    } else {
7616                        None
7617                    }
7618                    .map(|direction| ExpandInfo {
7619                        direction,
7620                        excerpt_range: last_excerpt.range.context.clone(),
7621                    })
7622                };
7623                self.point += Point::new(1, 0);
7624                return Some(RowInfo {
7625                    buffer_id: Some(last_excerpt.buffer_id),
7626                    buffer_row: Some(last_row),
7627                    multibuffer_row: Some(multibuffer_row),
7628                    diff_status: None,
7629                    wrapped_buffer_row: None,
7630                    expand_info,
7631                });
7632            } else {
7633                return None;
7634            };
7635        }
7636
7637        let overshoot = self.point - region.range.start;
7638        let buffer_point = region.buffer_range.start + overshoot;
7639        let expand_info = if self.is_singleton {
7640            None
7641        } else {
7642            let needs_expand_up = self.point.row == region.range.start.row
7643                && self.cursor.is_at_start_of_excerpt()
7644                && buffer_point.row > 0;
7645            let needs_expand_down = (region.excerpt.has_trailing_newline
7646                && self.point.row + 1 == region.range.end.row
7647                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7648                && self.cursor.is_at_end_of_excerpt()
7649                && buffer_point.row < region.buffer.max_point().row;
7650
7651            if needs_expand_up && needs_expand_down {
7652                Some(ExpandExcerptDirection::UpAndDown)
7653            } else if needs_expand_up {
7654                Some(ExpandExcerptDirection::Up)
7655            } else if needs_expand_down {
7656                Some(ExpandExcerptDirection::Down)
7657            } else {
7658                None
7659            }
7660            .map(|direction| ExpandInfo {
7661                direction,
7662                excerpt_range: region.excerpt.range.context.clone(),
7663            })
7664        };
7665
7666        let result = Some(RowInfo {
7667            buffer_id: Some(region.buffer.remote_id()),
7668            buffer_row: Some(buffer_point.row),
7669            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7670            diff_status: region
7671                .diff_hunk_status
7672                .filter(|_| self.point < region.range.end),
7673            expand_info,
7674            wrapped_buffer_row: None,
7675        });
7676        self.point += Point::new(1, 0);
7677        result
7678    }
7679}
7680
7681impl<'a> MultiBufferChunks<'a> {
7682    pub fn offset(&self) -> MultiBufferOffset {
7683        self.range.start
7684    }
7685
7686    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7687        self.diff_transforms.seek(&range.end, Bias::Right);
7688        let mut excerpt_end = self.diff_transforms.start().1;
7689        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7690            let overshoot = range.end - self.diff_transforms.start().0;
7691            excerpt_end += overshoot;
7692        }
7693
7694        self.diff_transforms.seek(&range.start, Bias::Right);
7695        let mut excerpt_start = self.diff_transforms.start().1;
7696        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7697            let overshoot = range.start - self.diff_transforms.start().0;
7698            excerpt_start += overshoot;
7699        }
7700
7701        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7702        self.buffer_chunk.take();
7703        self.range = range;
7704    }
7705
7706    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7707        self.excerpt_offset_range = new_range.clone();
7708        self.excerpts.seek(&new_range.start, Bias::Right);
7709        if let Some(excerpt) = self.excerpts.item() {
7710            let excerpt_start = *self.excerpts.start();
7711            if let Some(excerpt_chunks) = self
7712                .excerpt_chunks
7713                .as_mut()
7714                .filter(|chunks| excerpt.end_anchor() == chunks.end)
7715            {
7716                excerpt.seek_chunks(
7717                    excerpt_chunks,
7718                    (self.excerpt_offset_range.start - excerpt_start)
7719                        ..(self.excerpt_offset_range.end - excerpt_start),
7720                    self.snapshot,
7721                );
7722            } else {
7723                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7724                    (self.excerpt_offset_range.start - excerpt_start)
7725                        ..(self.excerpt_offset_range.end - excerpt_start),
7726                    self.language_aware,
7727                    self.snapshot,
7728                ));
7729            }
7730        } else {
7731            self.excerpt_chunks = None;
7732        }
7733    }
7734
7735    #[ztracing::instrument(skip_all)]
7736    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7737        loop {
7738            if self.excerpt_offset_range.is_empty() {
7739                return None;
7740            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7741                self.excerpt_offset_range.start += chunk.text.len();
7742                return Some(chunk);
7743            } else {
7744                self.excerpts.next();
7745                let excerpt = self.excerpts.item()?;
7746                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7747                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7748                    self.language_aware,
7749                    self.snapshot,
7750                ));
7751            }
7752        }
7753    }
7754}
7755
7756impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7757    type Item = &'a str;
7758
7759    fn next(&mut self) -> Option<Self::Item> {
7760        let mut region = self.cursor.region()?;
7761        if self.offset == region.range.start {
7762            self.cursor.prev();
7763            region = self.cursor.region()?;
7764            let start_overshoot = self.start.saturating_sub(region.range.start);
7765            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7766                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7767            ));
7768        }
7769
7770        if self.offset == region.range.end && region.has_trailing_newline {
7771            self.offset -= 1;
7772            Some("\n")
7773        } else {
7774            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7775            self.offset -= chunk.len();
7776            Some(chunk)
7777        }
7778    }
7779}
7780
7781impl<'a> Iterator for MultiBufferChunks<'a> {
7782    type Item = Chunk<'a>;
7783
7784    #[ztracing::instrument(skip_all)]
7785    fn next(&mut self) -> Option<Chunk<'a>> {
7786        if self.range.start >= self.range.end {
7787            return None;
7788        }
7789        if self.range.start == self.diff_transforms.end().0 {
7790            self.diff_transforms.next();
7791        }
7792
7793        let diff_transform_start = self.diff_transforms.start().0;
7794        let diff_transform_end = self.diff_transforms.end().0;
7795        debug_assert!(
7796            self.range.start < diff_transform_end,
7797            "{:?} < {:?} of ({1:?}..{2:?})",
7798            self.range.start,
7799            diff_transform_end,
7800            diff_transform_start
7801        );
7802
7803        let diff_transform = self.diff_transforms.item()?;
7804        match diff_transform {
7805            DiffTransform::BufferContent { .. } => {
7806                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7807                    chunk
7808                } else {
7809                    let chunk = self.next_excerpt_chunk().unwrap();
7810                    self.buffer_chunk.insert(chunk)
7811                };
7812
7813                let chunk_end = self.range.start + chunk.text.len();
7814                let diff_transform_end = diff_transform_end.min(self.range.end);
7815
7816                if diff_transform_end < chunk_end {
7817                    let split_idx = diff_transform_end - self.range.start;
7818                    let (before, after) = chunk.text.split_at(split_idx);
7819                    self.range.start = diff_transform_end;
7820                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7821                    let chars = chunk.chars & mask;
7822                    let tabs = chunk.tabs & mask;
7823                    let newlines = chunk.newlines & mask;
7824
7825                    chunk.text = after;
7826                    chunk.chars = chunk.chars >> split_idx;
7827                    chunk.tabs = chunk.tabs >> split_idx;
7828                    chunk.newlines = chunk.newlines >> split_idx;
7829
7830                    Some(Chunk {
7831                        text: before,
7832                        chars,
7833                        tabs,
7834                        newlines,
7835                        ..chunk.clone()
7836                    })
7837                } else {
7838                    self.range.start = chunk_end;
7839                    self.buffer_chunk.take()
7840                }
7841            }
7842            DiffTransform::DeletedHunk {
7843                buffer_id,
7844                base_text_byte_range,
7845                has_trailing_newline,
7846                ..
7847            } => {
7848                let base_text_start =
7849                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7850                let base_text_end =
7851                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7852                let base_text_end = base_text_end.min(base_text_byte_range.end);
7853
7854                let mut chunks = if let Some((_, mut chunks)) = self
7855                    .diff_base_chunks
7856                    .take()
7857                    .filter(|(id, _)| id == buffer_id)
7858                {
7859                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7860                    {
7861                        chunks.seek(base_text_start..base_text_end);
7862                    }
7863                    chunks
7864                } else {
7865                    let base_buffer = &self.snapshot.diffs.get(buffer_id)?.base_text();
7866                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7867                };
7868
7869                let chunk = if let Some(chunk) = chunks.next() {
7870                    self.range.start += chunk.text.len();
7871                    self.diff_base_chunks = Some((*buffer_id, chunks));
7872                    chunk
7873                } else {
7874                    debug_assert!(has_trailing_newline);
7875                    self.range.start += "\n".len();
7876                    Chunk {
7877                        text: "\n",
7878                        chars: 1u128,
7879                        newlines: 1u128,
7880                        ..Default::default()
7881                    }
7882                };
7883                Some(chunk)
7884            }
7885        }
7886    }
7887}
7888
7889impl MultiBufferBytes<'_> {
7890    fn consume(&mut self, len: usize) {
7891        self.range.start += len;
7892        self.chunk = &self.chunk[len..];
7893
7894        if !self.range.is_empty() && self.chunk.is_empty() {
7895            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7896                self.chunk = chunk;
7897            } else if self.has_trailing_newline {
7898                self.has_trailing_newline = false;
7899                self.chunk = b"\n";
7900            } else {
7901                self.cursor.next();
7902                if let Some(region) = self.cursor.region() {
7903                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7904                        region.buffer_range.start
7905                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7906                                .min(region.buffer_range.end),
7907                    );
7908                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7909                    self.excerpt_bytes = Some(excerpt_bytes);
7910                    self.has_trailing_newline =
7911                        region.has_trailing_newline && self.range.end >= region.range.end;
7912                    if self.chunk.is_empty() && self.has_trailing_newline {
7913                        self.has_trailing_newline = false;
7914                        self.chunk = b"\n";
7915                    }
7916                }
7917            }
7918        }
7919    }
7920}
7921
7922impl<'a> Iterator for MultiBufferBytes<'a> {
7923    type Item = &'a [u8];
7924
7925    fn next(&mut self) -> Option<Self::Item> {
7926        let chunk = self.chunk;
7927        if chunk.is_empty() {
7928            None
7929        } else {
7930            self.consume(chunk.len());
7931            Some(chunk)
7932        }
7933    }
7934}
7935
7936impl io::Read for MultiBufferBytes<'_> {
7937    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7938        let len = cmp::min(buf.len(), self.chunk.len());
7939        buf[..len].copy_from_slice(&self.chunk[..len]);
7940        if len > 0 {
7941            self.consume(len);
7942        }
7943        Ok(len)
7944    }
7945}
7946
7947impl io::Read for ReversedMultiBufferBytes<'_> {
7948    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7949        let len = cmp::min(buf.len(), self.chunk.len());
7950        buf[..len].copy_from_slice(&self.chunk[..len]);
7951        buf[..len].reverse();
7952        if len > 0 {
7953            self.range.end -= len;
7954            self.chunk = &self.chunk[..self.chunk.len() - len];
7955            if !self.range.is_empty()
7956                && self.chunk.is_empty()
7957                && let Some(chunk) = self.chunks.next()
7958            {
7959                self.chunk = chunk.as_bytes();
7960            }
7961        }
7962        Ok(len)
7963    }
7964}
7965
7966impl<'a> Iterator for ExcerptChunks<'a> {
7967    type Item = Chunk<'a>;
7968
7969    fn next(&mut self) -> Option<Self::Item> {
7970        if let Some(chunk) = self.content_chunks.next() {
7971            return Some(chunk);
7972        }
7973
7974        if self.has_footer {
7975            let text = "\n";
7976            let chars = 0b1;
7977            let newlines = 0b1;
7978            self.has_footer = false;
7979            return Some(Chunk {
7980                text,
7981                chars,
7982                newlines,
7983                ..Default::default()
7984            });
7985        }
7986
7987        None
7988    }
7989}
7990
7991impl ToOffset for Point {
7992    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7993        snapshot.point_to_offset(*self)
7994    }
7995    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7996        snapshot.point_to_offset_utf16(*self)
7997    }
7998}
7999
8000impl ToOffset for MultiBufferOffset {
8001    #[track_caller]
8002    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8003        assert!(
8004            *self <= snapshot.len(),
8005            "offset {} is greater than the snapshot.len() {}",
8006            self.0,
8007            snapshot.len().0,
8008        );
8009        *self
8010    }
8011    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8012        snapshot.offset_to_offset_utf16(*self)
8013    }
8014}
8015
8016impl ToOffset for MultiBufferOffsetUtf16 {
8017    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8018        snapshot.offset_utf16_to_offset(*self)
8019    }
8020
8021    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8022        *self
8023    }
8024}
8025
8026impl ToOffset for PointUtf16 {
8027    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8028        snapshot.point_utf16_to_offset(*self)
8029    }
8030    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8031        snapshot.point_utf16_to_offset_utf16(*self)
8032    }
8033}
8034
8035impl ToPoint for MultiBufferOffset {
8036    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8037        snapshot.offset_to_point(*self)
8038    }
8039    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8040        snapshot.offset_to_point_utf16(*self)
8041    }
8042}
8043
8044impl ToPoint for Point {
8045    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8046        *self
8047    }
8048    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8049        snapshot.point_to_point_utf16(*self)
8050    }
8051}
8052
8053impl ToPoint for PointUtf16 {
8054    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8055        snapshot.point_utf16_to_point(*self)
8056    }
8057    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8058        *self
8059    }
8060}
8061
8062#[cfg(debug_assertions)]
8063pub mod debug {
8064    use super::*;
8065
8066    pub trait ToMultiBufferDebugRanges {
8067        fn to_multi_buffer_debug_ranges(
8068            &self,
8069            snapshot: &MultiBufferSnapshot,
8070        ) -> Vec<Range<MultiBufferOffset>>;
8071    }
8072
8073    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8074        fn to_multi_buffer_debug_ranges(
8075            &self,
8076            snapshot: &MultiBufferSnapshot,
8077        ) -> Vec<Range<MultiBufferOffset>> {
8078            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8079        }
8080    }
8081
8082    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8083        fn to_multi_buffer_debug_ranges(
8084            &self,
8085            snapshot: &MultiBufferSnapshot,
8086        ) -> Vec<Range<MultiBufferOffset>> {
8087            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8088                .to_multi_buffer_debug_ranges(snapshot)
8089        }
8090    }
8091
8092    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8093        fn to_multi_buffer_debug_ranges(
8094            &self,
8095            snapshot: &MultiBufferSnapshot,
8096        ) -> Vec<Range<MultiBufferOffset>> {
8097            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8098        }
8099    }
8100
8101    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8102        fn to_multi_buffer_debug_ranges(
8103            &self,
8104            snapshot: &MultiBufferSnapshot,
8105        ) -> Vec<Range<MultiBufferOffset>> {
8106            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8107        }
8108    }
8109
8110    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8111        fn to_multi_buffer_debug_ranges(
8112            &self,
8113            snapshot: &MultiBufferSnapshot,
8114        ) -> Vec<Range<MultiBufferOffset>> {
8115            self.iter()
8116                .map(|item| {
8117                    let offset = item.to_offset(snapshot);
8118                    offset..offset
8119                })
8120                .collect()
8121        }
8122    }
8123
8124    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8125        fn to_multi_buffer_debug_ranges(
8126            &self,
8127            snapshot: &MultiBufferSnapshot,
8128        ) -> Vec<Range<MultiBufferOffset>> {
8129            self.iter()
8130                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8131                .collect()
8132        }
8133    }
8134}