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