multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use crate::anchor::ExcerptAnchor;
   8
   9use self::transaction::History;
  10
  11pub use anchor::{Anchor, AnchorRangeExt};
  12
  13use anchor::AnchorSeekTarget;
  14use anyhow::{Result, anyhow};
  15use buffer_diff::{
  16    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  17    DiffHunkStatus, DiffHunkStatusKind,
  18};
  19use clock::ReplicaId;
  20use collections::{BTreeMap, Bound, HashMap, HashSet};
  21use gpui::{App, Context, Entity, EventEmitter};
  22use itertools::Itertools;
  23use language::{
  24    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  25    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  26    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  27    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  28    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  29    language_settings::{LanguageSettings, language_settings},
  30};
  31
  32#[cfg(any(test, feature = "test-support"))]
  33use gpui::AppContext as _;
  34
  35use rope::DimensionPair;
  36use smallvec::SmallVec;
  37use smol::future::yield_now;
  38use std::{
  39    any::type_name,
  40    borrow::Cow,
  41    cell::{Cell, OnceCell, Ref, RefCell},
  42    cmp::{self, Ordering},
  43    fmt,
  44    future::Future,
  45    io,
  46    iter::{self, FromIterator},
  47    mem,
  48    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  49    rc::Rc,
  50    str,
  51    sync::{Arc, OnceLock},
  52    time::Duration,
  53};
  54use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  55use text::{
  56    BufferId, Edit, LineIndent, TextSummary,
  57    locator::Locator,
  58    subscription::{Subscription, Topic},
  59};
  60use theme::SyntaxTheme;
  61use ztracing::instrument;
  62
  63pub use self::path_key::{PathExcerptInsertResult, PathKey};
  64
  65pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  66
  67pub fn excerpt_context_lines(cx: &App) -> u32 {
  68    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  69}
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from buffer IDs to their diff states
  81    diffs: HashMap<BufferId, DiffState>,
  82    subscriptions: Topic<MultiBufferOffset>,
  83    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  84    singleton: bool,
  85    /// The history of the multi-buffer.
  86    history: History,
  87    /// The explicit title of the multi-buffer.
  88    /// If `None`, it will be derived from the underlying path or content.
  89    title: Option<String>,
  90    /// The writing capability of the multi-buffer.
  91    capability: Capability,
  92    buffer_changed_since_sync: Rc<Cell<bool>>,
  93}
  94
  95#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
  96pub struct PathKeyIndex(u64);
  97
  98pub struct ExcerptInfo {
  99    path_key: PathKey,
 100    buffer_id: BufferId,
 101    range: ExcerptRange<text::Anchor>,
 102}
 103
 104#[derive(Clone, Debug, PartialEq, Eq)]
 105pub enum Event {
 106    BufferUpdated {
 107        buffer: Entity<Buffer>,
 108        path_key: PathKey,
 109        ranges: Vec<Range<text::Anchor>>,
 110    },
 111    BuffersRemoved {
 112        removed_buffer_ids: Vec<BufferId>,
 113    },
 114    BuffersEdited {
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The range within the buffer's diff base that this hunk corresponds to.
 144    pub diff_base_byte_range: Range<BufferOffset>,
 145    /// The status of this hunk (added/modified/deleted and secondary status).
 146    pub status: DiffHunkStatus,
 147    /// The word diffs for this hunk.
 148    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 149}
 150
 151impl MultiBufferDiffHunk {
 152    pub fn status(&self) -> DiffHunkStatus {
 153        self.status
 154    }
 155
 156    pub fn is_created_file(&self) -> bool {
 157        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 158            && self.buffer_range.start.is_min()
 159            && self.buffer_range.end.is_max()
 160    }
 161
 162    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 163        let start = Anchor::text(self.buffer_range.start);
 164        let end = Anchor::text(self.buffer_range.end);
 165        start..end
 166    }
 167}
 168
 169pub type MultiBufferPoint = Point;
 170type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 171type ExcerptPoint = ExcerptDimension<Point>;
 172
 173#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 174#[serde(transparent)]
 175pub struct MultiBufferRow(pub u32);
 176
 177impl MultiBufferRow {
 178    pub const MIN: Self = Self(0);
 179    pub const MAX: Self = Self(u32::MAX);
 180}
 181
 182impl ops::Add<usize> for MultiBufferRow {
 183    type Output = Self;
 184
 185    fn add(self, rhs: usize) -> Self::Output {
 186        MultiBufferRow(self.0 + rhs as u32)
 187    }
 188}
 189
 190pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 191    type TextDimension: TextDimension;
 192    fn from_summary(summary: &MBTextSummary) -> Self;
 193
 194    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 195
 196    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 197}
 198
 199// todo(lw): MultiBufferPoint
 200impl MultiBufferDimension for Point {
 201    type TextDimension = Point;
 202    fn from_summary(summary: &MBTextSummary) -> Self {
 203        summary.lines
 204    }
 205
 206    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 207        *self += *other;
 208    }
 209
 210    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 211        *self += summary.lines;
 212    }
 213}
 214
 215// todo(lw): MultiBufferPointUtf16
 216impl MultiBufferDimension for PointUtf16 {
 217    type TextDimension = PointUtf16;
 218    fn from_summary(summary: &MBTextSummary) -> Self {
 219        summary.lines_utf16()
 220    }
 221
 222    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 223        *self += *other;
 224    }
 225
 226    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 227        *self += summary.lines_utf16();
 228    }
 229}
 230
 231#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 232pub struct MultiBufferOffset(pub usize);
 233
 234impl fmt::Display for MultiBufferOffset {
 235    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 236        write!(f, "{}", self.0)
 237    }
 238}
 239
 240impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 241    type Sampler = MultiBufferOffsetUniformSampler;
 242}
 243
 244pub struct MultiBufferOffsetUniformSampler {
 245    sampler: rand::distr::uniform::UniformUsize,
 246}
 247
 248impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 249    type X = MultiBufferOffset;
 250
 251    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 252    where
 253        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 254        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 255    {
 256        let low = *low_b.borrow();
 257        let high = *high_b.borrow();
 258        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 259        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 260    }
 261
 262    #[inline] // if the range is constant, this helps LLVM to do the
 263    // calculations at compile-time.
 264    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 265    where
 266        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 267        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 268    {
 269        let low = *low_b.borrow();
 270        let high = *high_b.borrow();
 271        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 272        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 273    }
 274
 275    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 276        MultiBufferOffset(self.sampler.sample(rng))
 277    }
 278}
 279impl MultiBufferDimension for MultiBufferOffset {
 280    type TextDimension = usize;
 281    fn from_summary(summary: &MBTextSummary) -> Self {
 282        summary.len
 283    }
 284
 285    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 286        self.0 += *other;
 287    }
 288
 289    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 290        *self += summary.len;
 291    }
 292}
 293impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 294    type TextDimension = OffsetUtf16;
 295    fn from_summary(summary: &MBTextSummary) -> Self {
 296        MultiBufferOffsetUtf16(summary.len_utf16)
 297    }
 298
 299    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 300        self.0 += *other;
 301    }
 302
 303    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 304        self.0 += summary.len_utf16;
 305    }
 306}
 307
 308#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 309pub struct BufferOffset(pub usize);
 310
 311impl TextDimension for BufferOffset {
 312    fn from_text_summary(summary: &TextSummary) -> Self {
 313        BufferOffset(usize::from_text_summary(summary))
 314    }
 315    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 316        BufferOffset(usize::from_chunk(chunk))
 317    }
 318    fn add_assign(&mut self, other: &Self) {
 319        TextDimension::add_assign(&mut self.0, &other.0);
 320    }
 321}
 322impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 323    fn zero(cx: ()) -> Self {
 324        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 325    }
 326
 327    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 328        usize::add_summary(&mut self.0, summary, cx);
 329    }
 330}
 331
 332impl Sub for BufferOffset {
 333    type Output = usize;
 334
 335    fn sub(self, other: BufferOffset) -> Self::Output {
 336        self.0 - other.0
 337    }
 338}
 339
 340impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 341    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 342        self.0 += other.key;
 343    }
 344}
 345
 346impl language::ToPoint for BufferOffset {
 347    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 348        self.0.to_point(snapshot)
 349    }
 350}
 351
 352impl language::ToPointUtf16 for BufferOffset {
 353    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 354        self.0.to_point_utf16(snapshot)
 355    }
 356}
 357
 358impl language::ToOffset for BufferOffset {
 359    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 360        self.0.to_offset(snapshot)
 361    }
 362}
 363
 364impl language::ToOffsetUtf16 for BufferOffset {
 365    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 366        self.0.to_offset_utf16(snapshot)
 367    }
 368}
 369
 370#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 371pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 372
 373impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 374    type Output = MultiBufferOffsetUtf16;
 375
 376    fn add(self, rhs: usize) -> Self::Output {
 377        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 378    }
 379}
 380
 381impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 382    type Output = Self;
 383
 384    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 385        MultiBufferOffsetUtf16(self.0 + rhs)
 386    }
 387}
 388
 389impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 390    fn add_assign(&mut self, rhs: OffsetUtf16) {
 391        self.0 += rhs;
 392    }
 393}
 394
 395impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 396    fn add_assign(&mut self, rhs: usize) {
 397        self.0.0 += rhs;
 398    }
 399}
 400
 401impl Sub for MultiBufferOffsetUtf16 {
 402    type Output = OffsetUtf16;
 403
 404    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 405        self.0 - other.0
 406    }
 407}
 408
 409impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 410    type Output = MultiBufferOffsetUtf16;
 411
 412    fn sub(self, other: OffsetUtf16) -> Self::Output {
 413        MultiBufferOffsetUtf16(self.0 - other)
 414    }
 415}
 416
 417#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 418pub struct BufferOffsetUtf16(pub OffsetUtf16);
 419
 420impl MultiBufferOffset {
 421    const ZERO: Self = Self(0);
 422    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 423        self.0.saturating_sub(other.0)
 424    }
 425    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 426        MultiBufferOffset(self.0.saturating_sub(other))
 427    }
 428}
 429
 430impl ops::Sub for MultiBufferOffset {
 431    type Output = usize;
 432
 433    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 434        self.0 - other.0
 435    }
 436}
 437
 438impl ops::Sub<usize> for MultiBufferOffset {
 439    type Output = Self;
 440
 441    fn sub(self, other: usize) -> Self::Output {
 442        MultiBufferOffset(self.0 - other)
 443    }
 444}
 445
 446impl ops::SubAssign<usize> for MultiBufferOffset {
 447    fn sub_assign(&mut self, other: usize) {
 448        self.0 -= other;
 449    }
 450}
 451
 452impl ops::Add<usize> for BufferOffset {
 453    type Output = Self;
 454
 455    fn add(self, rhs: usize) -> Self::Output {
 456        BufferOffset(self.0 + rhs)
 457    }
 458}
 459
 460impl ops::AddAssign<usize> for BufferOffset {
 461    fn add_assign(&mut self, other: usize) {
 462        self.0 += other;
 463    }
 464}
 465
 466impl ops::Add<usize> for MultiBufferOffset {
 467    type Output = Self;
 468
 469    fn add(self, rhs: usize) -> Self::Output {
 470        MultiBufferOffset(self.0 + rhs)
 471    }
 472}
 473
 474impl ops::AddAssign<usize> for MultiBufferOffset {
 475    fn add_assign(&mut self, other: usize) {
 476        self.0 += other;
 477    }
 478}
 479
 480impl ops::Add<isize> for MultiBufferOffset {
 481    type Output = Self;
 482
 483    fn add(self, rhs: isize) -> Self::Output {
 484        MultiBufferOffset((self.0 as isize + rhs) as usize)
 485    }
 486}
 487
 488impl ops::Add for MultiBufferOffset {
 489    type Output = Self;
 490
 491    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 492        MultiBufferOffset(self.0 + rhs.0)
 493    }
 494}
 495
 496impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 497    fn add_assign(&mut self, other: MultiBufferOffset) {
 498        self.0 += other.0;
 499    }
 500}
 501
 502pub trait ToOffset: 'static + fmt::Debug {
 503    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 504    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 505}
 506
 507pub trait ToPoint: 'static + fmt::Debug {
 508    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 509    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 510}
 511
 512struct BufferState {
 513    buffer: Entity<Buffer>,
 514    last_version: RefCell<clock::Global>,
 515    last_non_text_state_update_count: Cell<usize>,
 516    _subscriptions: [gpui::Subscription; 2],
 517}
 518
 519struct DiffState {
 520    diff: Entity<BufferDiff>,
 521    main_buffer: Option<Entity<language::Buffer>>,
 522    _subscription: gpui::Subscription,
 523}
 524
 525impl DiffState {
 526    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 527        DiffStateSnapshot {
 528            diff: self.diff.read(cx).snapshot(cx),
 529            main_buffer: self.main_buffer.as_ref().map(|b| b.read(cx).snapshot()),
 530        }
 531    }
 532}
 533
 534#[derive(Clone)]
 535struct DiffStateSnapshot {
 536    diff: BufferDiffSnapshot,
 537    main_buffer: Option<language::BufferSnapshot>,
 538}
 539
 540impl std::ops::Deref for DiffStateSnapshot {
 541    type Target = BufferDiffSnapshot;
 542
 543    fn deref(&self) -> &Self::Target {
 544        &self.diff
 545    }
 546}
 547
 548impl DiffState {
 549    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 550        DiffState {
 551            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 552                BufferDiffEvent::DiffChanged(DiffChanged {
 553                    changed_range,
 554                    base_text_changed_range: _,
 555                    extended_range,
 556                }) => {
 557                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 558                    let range = if use_extended {
 559                        extended_range.clone()
 560                    } else {
 561                        changed_range.clone()
 562                    };
 563                    if let Some(range) = range {
 564                        this.buffer_diff_changed(diff, range, cx)
 565                    }
 566                    cx.emit(Event::BufferDiffChanged);
 567                }
 568                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 569                _ => {}
 570            }),
 571            diff,
 572            main_buffer: None,
 573        }
 574    }
 575
 576    fn new_inverted(
 577        diff: Entity<BufferDiff>,
 578        main_buffer: Entity<language::Buffer>,
 579        cx: &mut Context<MultiBuffer>,
 580    ) -> Self {
 581        let weak_main_buffer = main_buffer.downgrade();
 582        DiffState {
 583            _subscription: cx.subscribe(&diff, {
 584                move |this, diff, event, cx| {
 585                    let Some(main_buffer) = weak_main_buffer.upgrade() else {
 586                        return;
 587                    };
 588                    match event {
 589                        BufferDiffEvent::DiffChanged(DiffChanged {
 590                            changed_range: _,
 591                            base_text_changed_range,
 592                            extended_range: _,
 593                        }) => {
 594                            this.inverted_buffer_diff_changed(
 595                                diff,
 596                                main_buffer,
 597                                base_text_changed_range.clone(),
 598                                cx,
 599                            );
 600                            cx.emit(Event::BufferDiffChanged);
 601                        }
 602                        BufferDiffEvent::LanguageChanged => {
 603                            this.inverted_buffer_diff_language_changed(diff, main_buffer, cx)
 604                        }
 605                        _ => {}
 606                    }
 607                }
 608            }),
 609            diff,
 610            main_buffer: Some(main_buffer),
 611        }
 612    }
 613}
 614
 615/// The contents of a [`MultiBuffer`] at a single point in time.
 616#[derive(Clone, Default)]
 617pub struct MultiBufferSnapshot {
 618    excerpts: SumTree<Excerpt>,
 619    path_keys_by_buffer: TreeMap<BufferId, PathKey>,
 620    path_keys_by_index: TreeMap<PathKeyIndex, PathKey>,
 621    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 622    diff_transforms: SumTree<DiffTransform>,
 623    non_text_state_update_count: usize,
 624    edit_count: usize,
 625    is_dirty: bool,
 626    has_deleted_file: bool,
 627    has_conflict: bool,
 628    has_inverted_diff: bool,
 629    singleton: bool,
 630    trailing_excerpt_update_count: usize,
 631    all_diff_hunks_expanded: bool,
 632    show_deleted_hunks: bool,
 633    use_extended_diff_range: bool,
 634    show_headers: bool,
 635}
 636
 637#[derive(Debug, Clone)]
 638enum DiffTransform {
 639    BufferContent {
 640        summary: MBTextSummary,
 641        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 642    },
 643    DeletedHunk {
 644        summary: TextSummary,
 645        buffer_id: BufferId,
 646        hunk_info: DiffTransformHunkInfo,
 647        base_text_byte_range: Range<usize>,
 648        has_trailing_newline: bool,
 649    },
 650}
 651
 652#[derive(Clone, Copy, Debug)]
 653struct DiffTransformHunkInfo {
 654    buffer_id: BufferId,
 655    hunk_start_anchor: text::Anchor,
 656    hunk_secondary_status: DiffHunkSecondaryStatus,
 657    is_logically_deleted: bool,
 658}
 659
 660impl Eq for DiffTransformHunkInfo {}
 661
 662impl PartialEq for DiffTransformHunkInfo {
 663    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 664        self.buffer_id == other.buffer_id && self.hunk_start_anchor == other.hunk_start_anchor
 665    }
 666}
 667
 668impl std::hash::Hash for DiffTransformHunkInfo {
 669    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 670        self.buffer_id.hash(state);
 671        self.hunk_start_anchor.hash(state);
 672    }
 673}
 674
 675#[derive(Clone)]
 676pub struct ExcerptBoundaryInfo {
 677    pub buffer: Arc<BufferSnapshot>,
 678    pub buffer_id: BufferId,
 679    pub range: ExcerptRange<text::Anchor>,
 680    pub end_row: MultiBufferRow,
 681}
 682
 683impl std::fmt::Debug for ExcerptBoundaryInfo {
 684    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 685        f.debug_struct(type_name::<Self>())
 686            .field("buffer_id", &self.buffer_id)
 687            .field("path", &self.buffer.file().map(|f| f.path()))
 688            .field("range", &self.range)
 689            .finish()
 690    }
 691}
 692
 693/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 694#[derive(Debug)]
 695pub struct ExcerptBoundary {
 696    pub prev: Option<ExcerptBoundaryInfo>,
 697    pub next: ExcerptBoundaryInfo,
 698    /// The row in the `MultiBuffer` where the boundary is located
 699    pub row: MultiBufferRow,
 700}
 701
 702impl ExcerptBoundary {
 703    pub fn starts_new_buffer(&self) -> bool {
 704        match (self.prev.as_ref(), &self.next) {
 705            (None, _) => true,
 706            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 707        }
 708    }
 709}
 710
 711#[derive(Clone, Debug, PartialEq, Eq)]
 712pub struct ExpandInfo {
 713    pub direction: ExpandExcerptDirection,
 714    pub excerpt_range: Range<text::Anchor>,
 715}
 716
 717#[derive(Clone, Debug, Default, PartialEq, Eq)]
 718pub struct RowInfo {
 719    pub buffer_id: Option<BufferId>,
 720    pub buffer_row: Option<u32>,
 721    pub multibuffer_row: Option<MultiBufferRow>,
 722    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 723    pub expand_info: Option<ExpandInfo>,
 724    pub wrapped_buffer_row: Option<u32>,
 725}
 726
 727/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 728#[derive(Clone)]
 729pub(crate) struct Excerpt {
 730    /// The location of the excerpt in the [`MultiBuffer`]
 731    pub(crate) path_key: PathKey,
 732    pub(crate) path_key_index: PathKeyIndex,
 733    /// A snapshot of the buffer being excerpted
 734    pub(crate) buffer: Arc<BufferSnapshot>,
 735    /// The range of the buffer to be shown in the excerpt
 736    pub(crate) range: ExcerptRange<text::Anchor>,
 737
 738    /// The last row in the excerpted slice of the buffer
 739    pub(crate) max_buffer_row: BufferRow,
 740    /// A summary of the text in the excerpt
 741    pub(crate) text_summary: TextSummary,
 742    pub(crate) has_trailing_newline: bool,
 743}
 744
 745/// A public view into an `Excerpt` in a [`MultiBuffer`].
 746///
 747/// Contains methods for getting the [`Buffer`] of the excerpt,
 748/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 749#[derive(Clone)]
 750pub struct MultiBufferExcerpt<'a> {
 751    excerpt: &'a Excerpt,
 752    diff_transforms:
 753        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 754    /// The offset in the multibuffer considering diff transforms.
 755    offset: MultiBufferOffset,
 756    /// The offset in the multibuffer without diff transforms.
 757    excerpt_offset: ExcerptOffset,
 758    buffer_offset: BufferOffset,
 759}
 760
 761/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 762/// These ranges are relative to the buffer itself
 763#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 764pub struct ExcerptRange<T> {
 765    /// The full range of text to be shown in the excerpt.
 766    pub context: Range<T>,
 767    /// The primary range of text to be highlighted in the excerpt.
 768    /// In a multi-buffer search, this would be the text that matched the search
 769    pub primary: Range<T>,
 770}
 771
 772impl<T: Clone> ExcerptRange<T> {
 773    pub fn new(context: Range<T>) -> Self {
 774        Self {
 775            context: context.clone(),
 776            primary: context,
 777        }
 778    }
 779}
 780
 781impl ExcerptRange<text::Anchor> {
 782    pub fn contains(&self, t: &text::Anchor, snapshot: &BufferSnapshot) -> bool {
 783        self.context.start.cmp(t, snapshot).is_le() && self.context.end.cmp(t, snapshot).is_ge()
 784    }
 785}
 786
 787#[derive(Clone, Debug)]
 788pub struct ExcerptSummary {
 789    path_key: PathKey,
 790    /// End of the excerpt
 791    max_anchor: text::Anchor,
 792    buffer_id: BufferId,
 793    widest_line_number: u32,
 794    text: MBTextSummary,
 795    count: usize,
 796}
 797
 798impl ExcerptSummary {
 799    pub fn min() -> Self {
 800        ExcerptSummary {
 801            path_key: PathKey::min(),
 802            max_anchor: text::Anchor::MIN,
 803            widest_line_number: 0,
 804            text: MBTextSummary::default(),
 805            count: 0,
 806        }
 807    }
 808
 809    pub fn len(&self) -> ExcerptOffset {
 810        ExcerptDimension(self.text.len)
 811    }
 812}
 813
 814#[derive(Debug, Clone)]
 815pub struct DiffTransformSummary {
 816    input: MBTextSummary,
 817    output: MBTextSummary,
 818}
 819
 820/// Summary of a string of text.
 821#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 822pub struct MBTextSummary {
 823    /// Length in bytes.
 824    pub len: MultiBufferOffset,
 825    /// Length in UTF-8.
 826    pub chars: usize,
 827    /// Length in UTF-16 code units
 828    pub len_utf16: OffsetUtf16,
 829    /// A point representing the number of lines and the length of the last line.
 830    ///
 831    /// In other words, it marks the point after the last byte in the text, (if
 832    /// EOF was a character, this would be its position).
 833    pub lines: Point,
 834    /// How many `char`s are in the first line
 835    pub first_line_chars: u32,
 836    /// How many `char`s are in the last line
 837    pub last_line_chars: u32,
 838    /// How many UTF-16 code units are in the last line
 839    pub last_line_len_utf16: u32,
 840    /// The row idx of the longest row
 841    pub longest_row: u32,
 842    /// How many `char`s are in the longest row
 843    pub longest_row_chars: u32,
 844}
 845
 846impl From<TextSummary> for MBTextSummary {
 847    fn from(summary: TextSummary) -> Self {
 848        MBTextSummary {
 849            len: MultiBufferOffset(summary.len),
 850            chars: summary.chars,
 851            len_utf16: summary.len_utf16,
 852            lines: summary.lines,
 853            first_line_chars: summary.first_line_chars,
 854            last_line_chars: summary.last_line_chars,
 855            last_line_len_utf16: summary.last_line_len_utf16,
 856            longest_row: summary.longest_row,
 857            longest_row_chars: summary.longest_row_chars,
 858        }
 859    }
 860}
 861
 862impl From<MBTextSummary> for TextSummary {
 863    fn from(summary: MBTextSummary) -> Self {
 864        TextSummary {
 865            len: summary.len.0,
 866            chars: summary.chars,
 867            len_utf16: summary.len_utf16,
 868            lines: summary.lines,
 869            first_line_chars: summary.first_line_chars,
 870            last_line_chars: summary.last_line_chars,
 871            last_line_len_utf16: summary.last_line_len_utf16,
 872            longest_row: summary.longest_row,
 873            longest_row_chars: summary.longest_row_chars,
 874        }
 875    }
 876}
 877
 878impl From<&str> for MBTextSummary {
 879    fn from(text: &str) -> Self {
 880        MBTextSummary::from(TextSummary::from(text))
 881    }
 882}
 883
 884impl MultiBufferDimension for MBTextSummary {
 885    type TextDimension = TextSummary;
 886
 887    fn from_summary(summary: &MBTextSummary) -> Self {
 888        *summary
 889    }
 890
 891    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 892        *self += *summary;
 893    }
 894
 895    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 896        *self += *summary;
 897    }
 898}
 899
 900impl AddAssign for MBTextSummary {
 901    fn add_assign(&mut self, other: MBTextSummary) {
 902        let joined_chars = self.last_line_chars + other.first_line_chars;
 903        if joined_chars > self.longest_row_chars {
 904            self.longest_row = self.lines.row;
 905            self.longest_row_chars = joined_chars;
 906        }
 907        if other.longest_row_chars > self.longest_row_chars {
 908            self.longest_row = self.lines.row + other.longest_row;
 909            self.longest_row_chars = other.longest_row_chars;
 910        }
 911
 912        if self.lines.row == 0 {
 913            self.first_line_chars += other.first_line_chars;
 914        }
 915
 916        if other.lines.row == 0 {
 917            self.last_line_chars += other.first_line_chars;
 918            self.last_line_len_utf16 += other.last_line_len_utf16;
 919        } else {
 920            self.last_line_chars = other.last_line_chars;
 921            self.last_line_len_utf16 = other.last_line_len_utf16;
 922        }
 923
 924        self.chars += other.chars;
 925        self.len += other.len;
 926        self.len_utf16 += other.len_utf16;
 927        self.lines += other.lines;
 928    }
 929}
 930
 931impl AddAssign<TextSummary> for MBTextSummary {
 932    fn add_assign(&mut self, other: TextSummary) {
 933        *self += MBTextSummary::from(other);
 934    }
 935}
 936
 937impl MBTextSummary {
 938    pub fn lines_utf16(&self) -> PointUtf16 {
 939        PointUtf16 {
 940            row: self.lines.row,
 941            column: self.last_line_len_utf16,
 942        }
 943    }
 944}
 945
 946impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 947where
 948    K: MultiBufferDimension,
 949    V: MultiBufferDimension,
 950{
 951    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 952
 953    fn from_summary(summary: &MBTextSummary) -> Self {
 954        Self {
 955            key: K::from_summary(summary),
 956            value: Some(V::from_summary(summary)),
 957        }
 958    }
 959
 960    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 961        self.key.add_text_dim(&summary.key);
 962        if let Some(value) = &mut self.value {
 963            if let Some(other_value) = summary.value.as_ref() {
 964                value.add_text_dim(other_value);
 965            }
 966        }
 967    }
 968
 969    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 970        self.key.add_mb_text_summary(summary);
 971        if let Some(value) = &mut self.value {
 972            value.add_mb_text_summary(summary);
 973        }
 974    }
 975}
 976
 977#[derive(Clone)]
 978pub struct MultiBufferRows<'a> {
 979    point: Point,
 980    is_empty: bool,
 981    is_singleton: bool,
 982    cursor: MultiBufferCursor<'a, Point, Point>,
 983}
 984
 985pub struct MultiBufferChunks<'a> {
 986    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 987    diff_transforms:
 988        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 989    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 990    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 991    buffer_chunk: Option<Chunk<'a>>,
 992    range: Range<MultiBufferOffset>,
 993    excerpt_offset_range: Range<ExcerptOffset>,
 994    excerpt_chunks: Option<ExcerptChunks<'a>>,
 995    language_aware: bool,
 996}
 997
 998pub struct ReversedMultiBufferChunks<'a> {
 999    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1000    current_chunks: Option<rope::Chunks<'a>>,
1001    start: MultiBufferOffset,
1002    offset: MultiBufferOffset,
1003}
1004
1005pub struct MultiBufferBytes<'a> {
1006    range: Range<MultiBufferOffset>,
1007    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
1008    excerpt_bytes: Option<text::Bytes<'a>>,
1009    has_trailing_newline: bool,
1010    chunk: &'a [u8],
1011}
1012
1013pub struct ReversedMultiBufferBytes<'a> {
1014    range: Range<MultiBufferOffset>,
1015    chunks: ReversedMultiBufferChunks<'a>,
1016    chunk: &'a [u8],
1017}
1018
1019#[derive(Clone)]
1020struct DiffTransforms<MBD> {
1021    output_dimension: OutputDimension<MBD>,
1022    excerpt_dimension: ExcerptDimension<MBD>,
1023}
1024
1025impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1026    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1027        Self {
1028            output_dimension: OutputDimension::zero(cx),
1029            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1030                cx,
1031            ),
1032        }
1033    }
1034
1035    fn add_summary(
1036        &mut self,
1037        summary: &'a DiffTransformSummary,
1038        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1039    ) {
1040        self.output_dimension.add_summary(summary, cx);
1041        self.excerpt_dimension.add_summary(summary, cx);
1042    }
1043}
1044
1045#[derive(Clone)]
1046struct MultiBufferCursor<'a, MBD, BD> {
1047    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1048    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1049    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1050    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1051}
1052
1053#[derive(Clone)]
1054struct MultiBufferRegion<'a, MBD, BD> {
1055    buffer: &'a BufferSnapshot,
1056    is_main_buffer: bool,
1057    diff_hunk_status: Option<DiffHunkStatus>,
1058    excerpt: &'a Excerpt,
1059    buffer_range: Range<BD>,
1060    range: Range<MBD>,
1061    has_trailing_newline: bool,
1062}
1063
1064struct ExcerptChunks<'a> {
1065    content_chunks: BufferChunks<'a>,
1066    has_footer: bool,
1067}
1068
1069#[derive(Debug)]
1070struct BufferEdit {
1071    range: Range<BufferOffset>,
1072    new_text: Arc<str>,
1073    is_insertion: bool,
1074    original_indent_column: Option<u32>,
1075}
1076
1077#[derive(Clone, Copy, Debug, PartialEq)]
1078enum DiffChangeKind {
1079    BufferEdited,
1080    DiffUpdated { base_changed: bool },
1081    ExpandOrCollapseHunks { expand: bool },
1082}
1083
1084#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1085pub enum ExpandExcerptDirection {
1086    Up,
1087    Down,
1088    UpAndDown,
1089}
1090
1091impl ExpandExcerptDirection {
1092    pub fn should_expand_up(&self) -> bool {
1093        match self {
1094            ExpandExcerptDirection::Up => true,
1095            ExpandExcerptDirection::Down => false,
1096            ExpandExcerptDirection::UpAndDown => true,
1097        }
1098    }
1099
1100    pub fn should_expand_down(&self) -> bool {
1101        match self {
1102            ExpandExcerptDirection::Up => false,
1103            ExpandExcerptDirection::Down => true,
1104            ExpandExcerptDirection::UpAndDown => true,
1105        }
1106    }
1107}
1108
1109#[derive(Clone, Debug, PartialEq)]
1110pub struct IndentGuide {
1111    pub buffer_id: BufferId,
1112    pub start_row: MultiBufferRow,
1113    pub end_row: MultiBufferRow,
1114    pub depth: u32,
1115    pub tab_size: u32,
1116    pub settings: IndentGuideSettings,
1117}
1118
1119impl IndentGuide {
1120    pub fn indent_level(&self) -> u32 {
1121        self.depth * self.tab_size
1122    }
1123}
1124
1125impl MultiBuffer {
1126    pub fn new(capability: Capability) -> Self {
1127        Self::new_(
1128            capability,
1129            MultiBufferSnapshot {
1130                show_headers: true,
1131                show_deleted_hunks: true,
1132                ..MultiBufferSnapshot::default()
1133            },
1134        )
1135    }
1136
1137    pub fn without_headers(capability: Capability) -> Self {
1138        Self::new_(
1139            capability,
1140            MultiBufferSnapshot {
1141                show_deleted_hunks: true,
1142                ..MultiBufferSnapshot::default()
1143            },
1144        )
1145    }
1146
1147    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1148        let mut this = Self::new_(
1149            buffer.read(cx).capability(),
1150            MultiBufferSnapshot {
1151                singleton: true,
1152                show_deleted_hunks: true,
1153                ..MultiBufferSnapshot::default()
1154            },
1155        );
1156        this.singleton = true;
1157        this.set_excerpts_for_path(
1158            PathKey::sorted(0),
1159            buffer.clone(),
1160            [Point::zero()..buffer.read(cx).max_point()],
1161            0,
1162            cx,
1163        );
1164        this
1165    }
1166
1167    #[inline]
1168    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1169        Self {
1170            snapshot: RefCell::new(snapshot),
1171            buffers: Default::default(),
1172            diffs: HashMap::default(),
1173            subscriptions: Topic::default(),
1174            singleton: false,
1175            capability,
1176            title: None,
1177            buffer_changed_since_sync: Default::default(),
1178            history: History::default(),
1179        }
1180    }
1181
1182    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1183        let mut buffers = BTreeMap::default();
1184        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1185        for (buffer_id, buffer_state) in self.buffers.iter() {
1186            buffer_state.buffer.update(new_cx, |buffer, _| {
1187                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1188            });
1189            buffers.insert(
1190                *buffer_id,
1191                BufferState {
1192                    buffer: buffer_state.buffer.clone(),
1193                    last_version: buffer_state.last_version.clone(),
1194                    last_non_text_state_update_count: buffer_state
1195                        .last_non_text_state_update_count
1196                        .clone(),
1197                    _subscriptions: [
1198                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1199                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1200                    ],
1201                },
1202            );
1203        }
1204        let mut diff_bases = HashMap::default();
1205        for (buffer_id, diff) in self.diffs.iter() {
1206            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1207        }
1208        Self {
1209            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1210            buffers,
1211            diffs: diff_bases,
1212            subscriptions: Default::default(),
1213            singleton: self.singleton,
1214            capability: self.capability,
1215            history: self.history.clone(),
1216            title: self.title.clone(),
1217            buffer_changed_since_sync,
1218        }
1219    }
1220
1221    pub fn set_group_interval(&mut self, group_interval: Duration) {
1222        self.history.set_group_interval(group_interval);
1223    }
1224
1225    pub fn with_title(mut self, title: String) -> Self {
1226        self.title = Some(title);
1227        self
1228    }
1229
1230    pub fn read_only(&self) -> bool {
1231        !self.capability.editable()
1232    }
1233
1234    pub fn capability(&self) -> Capability {
1235        self.capability
1236    }
1237
1238    /// Returns an up-to-date snapshot of the MultiBuffer.
1239    #[ztracing::instrument(skip_all)]
1240    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1241        self.sync(cx);
1242        self.snapshot.borrow().clone()
1243    }
1244
1245    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1246        self.sync(cx);
1247        self.snapshot.borrow()
1248    }
1249
1250    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1251        if self.singleton {
1252            Some(self.buffers.values().next().unwrap().buffer.clone())
1253        } else {
1254            None
1255        }
1256    }
1257
1258    pub fn is_singleton(&self) -> bool {
1259        self.singleton
1260    }
1261
1262    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1263        self.subscriptions.subscribe()
1264    }
1265
1266    pub fn is_dirty(&self, cx: &App) -> bool {
1267        self.read(cx).is_dirty()
1268    }
1269
1270    pub fn has_deleted_file(&self, cx: &App) -> bool {
1271        self.read(cx).has_deleted_file()
1272    }
1273
1274    pub fn has_conflict(&self, cx: &App) -> bool {
1275        self.read(cx).has_conflict()
1276    }
1277
1278    // The `is_empty` signature doesn't match what clippy expects
1279    #[allow(clippy::len_without_is_empty)]
1280    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1281        self.read(cx).len()
1282    }
1283
1284    pub fn is_empty(&self) -> bool {
1285        self.buffers.is_empty()
1286    }
1287
1288    pub fn edit<I, S, T>(
1289        &mut self,
1290        edits: I,
1291        autoindent_mode: Option<AutoindentMode>,
1292        cx: &mut Context<Self>,
1293    ) where
1294        I: IntoIterator<Item = (Range<S>, T)>,
1295        S: ToOffset,
1296        T: Into<Arc<str>>,
1297    {
1298        self.edit_internal(edits, autoindent_mode, true, cx);
1299    }
1300
1301    pub fn edit_non_coalesce<I, S, T>(
1302        &mut self,
1303        edits: I,
1304        autoindent_mode: Option<AutoindentMode>,
1305        cx: &mut Context<Self>,
1306    ) where
1307        I: IntoIterator<Item = (Range<S>, T)>,
1308        S: ToOffset,
1309        T: Into<Arc<str>>,
1310    {
1311        self.edit_internal(edits, autoindent_mode, false, cx);
1312    }
1313
1314    fn edit_internal<I, S, T>(
1315        &mut self,
1316        edits: I,
1317        autoindent_mode: Option<AutoindentMode>,
1318        coalesce_adjacent: bool,
1319        cx: &mut Context<Self>,
1320    ) where
1321        I: IntoIterator<Item = (Range<S>, T)>,
1322        S: ToOffset,
1323        T: Into<Arc<str>>,
1324    {
1325        if self.read_only() || self.buffers.is_empty() {
1326            return;
1327        }
1328        self.sync_mut(cx);
1329        let edits = edits
1330            .into_iter()
1331            .map(|(range, new_text)| {
1332                let mut range = range.start.to_offset(self.snapshot.get_mut())
1333                    ..range.end.to_offset(self.snapshot.get_mut());
1334                if range.start > range.end {
1335                    mem::swap(&mut range.start, &mut range.end);
1336                }
1337                (range, new_text.into())
1338            })
1339            .collect::<Vec<_>>();
1340
1341        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1342
1343        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1344        fn edit_internal(
1345            this: &mut MultiBuffer,
1346            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1347            mut autoindent_mode: Option<AutoindentMode>,
1348            coalesce_adjacent: bool,
1349            cx: &mut Context<MultiBuffer>,
1350        ) {
1351            let original_indent_columns = match &mut autoindent_mode {
1352                Some(AutoindentMode::Block {
1353                    original_indent_columns,
1354                }) => mem::take(original_indent_columns),
1355                _ => Default::default(),
1356            };
1357
1358            let buffer_edits = MultiBuffer::convert_edits_to_buffer_edits(
1359                edits,
1360                this.snapshot.get_mut(),
1361                &original_indent_columns,
1362            );
1363
1364            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1365            for (buffer_id, mut edits) in buffer_edits {
1366                buffer_ids.push(buffer_id);
1367                edits.sort_by_key(|edit| edit.range.start);
1368                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1369                    let mut edits = edits.into_iter().peekable();
1370                    let mut insertions = Vec::new();
1371                    let mut original_indent_columns = Vec::new();
1372                    let mut deletions = Vec::new();
1373                    let empty_str: Arc<str> = Arc::default();
1374                    while let Some(BufferEdit {
1375                        mut range,
1376                        mut new_text,
1377                        mut is_insertion,
1378                        original_indent_column,
1379                    }) = edits.next()
1380                    {
1381                        while let Some(BufferEdit {
1382                            range: next_range,
1383                            is_insertion: next_is_insertion,
1384                            new_text: next_new_text,
1385                            ..
1386                        }) = edits.peek()
1387                        {
1388                            let should_coalesce = if coalesce_adjacent {
1389                                range.end >= next_range.start
1390                            } else {
1391                                range.end > next_range.start
1392                            };
1393
1394                            if should_coalesce {
1395                                range.end = cmp::max(next_range.end, range.end);
1396                                is_insertion |= *next_is_insertion;
1397                                new_text = format!("{new_text}{next_new_text}").into();
1398                                edits.next();
1399                            } else {
1400                                break;
1401                            }
1402                        }
1403
1404                        if is_insertion {
1405                            original_indent_columns.push(original_indent_column);
1406                            insertions.push((
1407                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1408                                new_text.clone(),
1409                            ));
1410                        } else if !range.is_empty() {
1411                            deletions.push((
1412                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1413                                empty_str.clone(),
1414                            ));
1415                        }
1416                    }
1417
1418                    let deletion_autoindent_mode =
1419                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1420                            Some(AutoindentMode::Block {
1421                                original_indent_columns: Default::default(),
1422                            })
1423                        } else {
1424                            autoindent_mode.clone()
1425                        };
1426                    let insertion_autoindent_mode =
1427                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1428                            Some(AutoindentMode::Block {
1429                                original_indent_columns,
1430                            })
1431                        } else {
1432                            autoindent_mode.clone()
1433                        };
1434
1435                    if coalesce_adjacent {
1436                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1437                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1438                    } else {
1439                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1440                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1441                    }
1442                })
1443            }
1444
1445            cx.emit(Event::BuffersEdited { buffer_ids });
1446        }
1447    }
1448
1449    fn convert_edits_to_buffer_edits(
1450        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1451        snapshot: &MultiBufferSnapshot,
1452        original_indent_columns: &[Option<u32>],
1453    ) -> HashMap<BufferId, Vec<BufferEdit>> {
1454        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1455        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1456        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1457            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1458
1459            cursor.seek(&range.start);
1460            let mut start_region = cursor.region().expect("start offset out of bounds");
1461            if !start_region.is_main_buffer {
1462                cursor.next();
1463                if let Some(region) = cursor.region() {
1464                    start_region = region;
1465                } else {
1466                    continue;
1467                }
1468            }
1469
1470            if range.end < start_region.range.start {
1471                continue;
1472            }
1473
1474            let start_region = start_region.clone();
1475            if range.end > start_region.range.end {
1476                cursor.seek_forward(&range.end);
1477            }
1478            let mut end_region = cursor.region().expect("end offset out of bounds");
1479            if !end_region.is_main_buffer {
1480                cursor.prev();
1481                if let Some(region) = cursor.region() {
1482                    end_region = region;
1483                } else {
1484                    continue;
1485                }
1486            }
1487
1488            if range.start > end_region.range.end {
1489                continue;
1490            }
1491
1492            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1493            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1494            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1495                .min(start_region.buffer_range.end);
1496            let buffer_end =
1497                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1498
1499            if start_region.excerpt == end_region.excerpt {
1500                if start_region.buffer.capability == Capability::ReadWrite
1501                    && start_region.is_main_buffer
1502                {
1503                    buffer_edits
1504                        .entry(start_region.buffer.remote_id())
1505                        .or_default()
1506                        .push(BufferEdit {
1507                            range: buffer_start..buffer_end,
1508                            new_text,
1509                            is_insertion: true,
1510                            original_indent_column,
1511                        });
1512                }
1513            } else {
1514                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1515                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1516                if start_region.buffer.capability == Capability::ReadWrite
1517                    && start_region.is_main_buffer
1518                {
1519                    buffer_edits
1520                        .entry(start_region.buffer.remote_id())
1521                        .or_default()
1522                        .push(BufferEdit {
1523                            range: start_excerpt_range,
1524                            new_text: new_text.clone(),
1525                            is_insertion: true,
1526                            original_indent_column,
1527                        });
1528                }
1529                if end_region.buffer.capability == Capability::ReadWrite
1530                    && end_region.is_main_buffer
1531                {
1532                    buffer_edits
1533                        .entry(end_region.buffer.remote_id())
1534                        .or_default()
1535                        .push(BufferEdit {
1536                            range: end_excerpt_range,
1537                            new_text: new_text.clone(),
1538                            is_insertion: false,
1539                            original_indent_column,
1540                        });
1541                }
1542                let end_region_excerpt = end_region.excerpt.clone();
1543
1544                cursor.seek(&range.start);
1545                cursor.next_excerpt();
1546                while let Some(region) = cursor.region() {
1547                    if region.excerpt == &end_region_excerpt {
1548                        break;
1549                    }
1550                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1551                        buffer_edits
1552                            .entry(region.buffer.remote_id())
1553                            .or_default()
1554                            .push(BufferEdit {
1555                                range: region.buffer_range.clone(),
1556                                new_text: new_text.clone(),
1557                                is_insertion: false,
1558                                original_indent_column,
1559                            });
1560                    }
1561                    cursor.next_excerpt();
1562                }
1563            }
1564        }
1565        buffer_edits
1566    }
1567
1568    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1569    where
1570        I: IntoIterator<Item = Range<S>>,
1571        S: ToOffset,
1572    {
1573        if self.read_only() || self.buffers.is_empty() {
1574            return;
1575        }
1576        self.sync_mut(cx);
1577        let empty = Arc::<str>::from("");
1578        let edits = ranges
1579            .into_iter()
1580            .map(|range| {
1581                let mut range = range.start.to_offset(self.snapshot.get_mut())
1582                    ..range.end.to_offset(&self.snapshot.get_mut());
1583                if range.start > range.end {
1584                    mem::swap(&mut range.start, &mut range.end);
1585                }
1586                (range, empty.clone())
1587            })
1588            .collect::<Vec<_>>();
1589
1590        return autoindent_ranges_internal(self, edits, cx);
1591
1592        fn autoindent_ranges_internal(
1593            this: &mut MultiBuffer,
1594            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1595            cx: &mut Context<MultiBuffer>,
1596        ) {
1597            let buffer_edits =
1598                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1599
1600            let mut buffer_ids = Vec::new();
1601            for (buffer_id, mut edits) in buffer_edits {
1602                buffer_ids.push(buffer_id);
1603                edits.sort_unstable_by_key(|edit| edit.range.start);
1604
1605                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1606                for edit in edits {
1607                    if let Some(last_range) = ranges.last_mut()
1608                        && edit.range.start <= last_range.end
1609                    {
1610                        last_range.end = last_range.end.max(edit.range.end);
1611                        continue;
1612                    }
1613                    ranges.push(edit.range);
1614                }
1615
1616                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1617                    buffer.autoindent_ranges(ranges, cx);
1618                })
1619            }
1620
1621            cx.emit(Event::BuffersEdited { buffer_ids });
1622        }
1623    }
1624
1625    pub fn set_active_selections(
1626        &self,
1627        selections: &[Selection<Anchor>],
1628        line_mode: bool,
1629        cursor_shape: CursorShape,
1630        cx: &mut Context<Self>,
1631    ) {
1632        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1633            Default::default();
1634        let snapshot = self.read(cx);
1635        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(());
1636        for selection in selections {
1637            let Some(start) = snapshot.anchor_seek_target(selection.start) else {
1638                continue;
1639            };
1640            let Some(end) = snapshot.anchor_seek_target(selection.end) else {
1641                continue;
1642            };
1643
1644            cursor.seek(&start, Bias::Left);
1645            while let Some(excerpt) = cursor.item()
1646                && sum_tree::SeekTarget::cmp(&end, &cursor.position, ()).is_gt()
1647            {
1648                let start = text::Anchor::max(
1649                    &excerpt.range.context.start,
1650                    &selection.start.text_anchor().unwrap_or(text::Anchor::MIN),
1651                    &excerpt.buffer,
1652                )
1653                .clone();
1654                let end = text::Anchor::min(
1655                    &excerpt.range.context.end,
1656                    &selection.end.text_anchor().unwrap_or(text::Anchor::MAX),
1657                    &excerpt.buffer,
1658                )
1659                .clone();
1660                selections_by_buffer
1661                    .entry(excerpt.buffer.remote_id())
1662                    .or_default()
1663                    .push(Selection {
1664                        id: selection.id,
1665                        start,
1666                        end,
1667                        reversed: selection.reversed,
1668                        goal: selection.goal,
1669                    });
1670
1671                cursor.next();
1672            }
1673        }
1674
1675        for (buffer_id, buffer_state) in self.buffers.iter() {
1676            if !selections_by_buffer.contains_key(buffer_id) {
1677                buffer_state
1678                    .buffer
1679                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1680            }
1681        }
1682
1683        for (buffer_id, selections) in selections_by_buffer {
1684            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1685                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1686            });
1687        }
1688    }
1689
1690    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1691        for buffer in self.buffers.values() {
1692            buffer
1693                .buffer
1694                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1695        }
1696    }
1697
1698    #[instrument(skip_all)]
1699    fn merge_excerpt_ranges<'a>(
1700        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1701    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1702        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1703        let mut counts: Vec<usize> = Vec::new();
1704        for range in expanded_ranges {
1705            if let Some(last_range) = merged_ranges.last_mut() {
1706                assert!(
1707                    last_range.context.start <= range.context.start,
1708                    "ranges must be sorted: {last_range:?} <= {range:?}"
1709                );
1710                if last_range.context.end >= range.context.start
1711                    || last_range.context.end.row + 1 == range.context.start.row
1712                {
1713                    last_range.context.end = range.context.end.max(last_range.context.end);
1714                    *counts.last_mut().unwrap() += 1;
1715                    continue;
1716                }
1717            }
1718            merged_ranges.push(range.clone());
1719            counts.push(1);
1720        }
1721        (merged_ranges, counts)
1722    }
1723
1724    pub fn clear(&mut self, cx: &mut Context<Self>) {
1725        self.sync_mut(cx);
1726        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1727        let MultiBufferSnapshot {
1728            excerpts,
1729            diffs: _,
1730            diff_transforms: _,
1731            non_text_state_update_count: _,
1732            edit_count: _,
1733            is_dirty,
1734            has_deleted_file,
1735            has_conflict,
1736            has_inverted_diff,
1737            singleton: _,
1738            trailing_excerpt_update_count,
1739            all_diff_hunks_expanded: _,
1740            show_deleted_hunks: _,
1741            use_extended_diff_range: _,
1742            show_headers: _,
1743            path_keys_by_buffer: _,
1744        } = self.snapshot.get_mut();
1745        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1746        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1747        *excerpts = Default::default();
1748        *trailing_excerpt_update_count += 1;
1749        *is_dirty = false;
1750        *has_deleted_file = false;
1751        *has_conflict = false;
1752        *has_inverted_diff = false;
1753
1754        let edits = Self::sync_diff_transforms(
1755            self.snapshot.get_mut(),
1756            vec![Edit {
1757                old: start..prev_len,
1758                new: start..start,
1759            }],
1760            DiffChangeKind::BufferEdited,
1761        );
1762        if !edits.is_empty() {
1763            self.subscriptions.publish(edits);
1764        }
1765        cx.emit(Event::Edited {
1766            edited_buffer: None,
1767        });
1768        cx.emit(Event::BuffersRemoved { removed_buffer_ids });
1769        cx.notify();
1770    }
1771
1772    #[ztracing::instrument(skip_all)]
1773    pub fn excerpts_for_buffer(
1774        &self,
1775        buffer_id: BufferId,
1776        cx: &App,
1777    ) -> Vec<ExcerptRange<text::Anchor>> {
1778        let mut excerpts = Vec::new();
1779        let snapshot = self.read(cx);
1780        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id).cloned() else {
1781            return excerpts;
1782        };
1783
1784        let mut cursor = snapshot.excerpts.cursor::<PathKey>(());
1785        cursor.seek_forward(&path_key, Bias::Left);
1786
1787        while let Some(item) = cursor.item()
1788            && item.path_key == path_key
1789        {
1790            excerpts.push(item.range.clone());
1791            cursor.next()
1792        }
1793        excerpts
1794    }
1795
1796    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1797        let snapshot = self.read(cx);
1798        let mut excerpts = snapshot
1799            .excerpts
1800            .cursor::<Dimensions<PathKey, ExcerptPoint>>(());
1801        let mut diff_transforms = snapshot
1802            .diff_transforms
1803            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
1804        diff_transforms.next();
1805        let mut result = Vec::new();
1806        let Some(path_key) = snapshot.path_keys_by_buffer.get(&buffer_id) else {
1807            return result;
1808        };
1809
1810        while let Some(excerpt) = excerpts.item()
1811            && &excerpt.path_key == path_key
1812        {
1813            let excerpt_start = excerpts.start().1;
1814            let excerpt_end = excerpt_start + excerpt.text_summary.lines;
1815
1816            diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1817            let overshoot = excerpt_start - diff_transforms.start().0;
1818            let start = diff_transforms.start().1 + overshoot;
1819
1820            diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1821            let overshoot = excerpt_end - diff_transforms.start().0;
1822            let end = diff_transforms.start().1 + overshoot;
1823
1824            result.push(start.0..end.0);
1825            excerpts.next()
1826        }
1827        result
1828    }
1829
1830    // todo!() this seems bogus
1831    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1832        self.snapshot
1833            .borrow()
1834            .excerpts
1835            .iter()
1836            .map(|entry| entry.buffer.remote_id())
1837            .collect()
1838    }
1839
1840    pub fn excerpt_containing(&self, position: impl ToOffset, cx: &App) -> Option<ExcerptInfo> {
1841        let snapshot = self.read(cx);
1842        let offset = position.to_offset(&snapshot);
1843
1844        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1845        cursor.seek(&offset);
1846        let excerpt = cursor.excerpt().or(snapshot.excerpts.last())?;
1847        Some(ExcerptInfo {
1848            path_key: excerpt.path_key.clone(),
1849            buffer_id: excerpt.buffer.remote_id(),
1850            range: excerpt.range.clone(),
1851        })
1852    }
1853
1854    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1855        let buffer_id = match anchor {
1856            Anchor::Min => self.snapshot(cx).excerpts.first()?.buffer.remote_id(),
1857            Anchor::Max => self.snapshot(cx).excerpts.last()?.buffer.remote_id(),
1858            Anchor::Text { buffer_id, .. } => buffer_id,
1859        };
1860        self.buffer(buffer_id)
1861    }
1862
1863    // If point is at the end of the buffer, the last excerpt is returned
1864    pub fn point_to_buffer_offset<T: ToOffset>(
1865        &self,
1866        point: T,
1867        cx: &App,
1868    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1869        let snapshot = self.read(cx);
1870        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1871        Some((
1872            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1873            offset,
1874        ))
1875    }
1876
1877    // If point is at the end of the buffer, the last excerpt is returned
1878    pub fn point_to_buffer_point<T: ToPoint>(
1879        &self,
1880        point: T,
1881        cx: &App,
1882    ) -> Option<(Entity<Buffer>, Point)> {
1883        let snapshot = self.read(cx);
1884        let (buffer, point) = snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1885        Some((self.buffers.get(&buffer.remote_id())?.buffer.clone(), point))
1886    }
1887
1888    pub fn buffer_point_to_anchor(
1889        &self,
1890        // todo(lw): We shouldn't need this?
1891        buffer: &Entity<Buffer>,
1892        point: Point,
1893        cx: &App,
1894    ) -> Option<Anchor> {
1895        let mut found = None;
1896        let snapshot = buffer.read(cx).snapshot();
1897        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1898            let start = range.context.start.to_point(&snapshot);
1899            let end = range.context.end.to_point(&snapshot);
1900            if start <= point && point < end {
1901                found = Some(snapshot.clip_point(point, Bias::Left));
1902                break;
1903            }
1904            if point < start {
1905                found = Some(start);
1906            }
1907            if point > end {
1908                found = Some(end);
1909            }
1910        }
1911
1912        Some(Anchor::text(snapshot.anchor_after(found?)))
1913    }
1914
1915    pub fn buffer_anchor_to_anchor(
1916        &self,
1917        // todo(lw): We shouldn't need this?
1918        buffer: &Entity<Buffer>,
1919        anchor: text::Anchor,
1920        cx: &App,
1921    ) -> Option<Anchor> {
1922        let snapshot = buffer.read(cx).snapshot();
1923        for range in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1924            if range.contains(&anchor, &snapshot) {
1925                return Some(Anchor::text(anchor));
1926            }
1927        }
1928
1929        None
1930    }
1931
1932    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
1933        &self,
1934        anchors: Anchors,
1935        cx: &mut Context<Self>,
1936    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
1937        let mut error = None;
1938        let mut futures = Vec::new();
1939        for anchor in anchors {
1940            if let Some(text_anchor) = anchor.text_anchor() {
1941                if let Some(buffer) = self.buffers.get(&text_anchor.buffer_id.unwrap()) {
1942                    buffer.buffer.update(cx, |buffer, _| {
1943                        futures.push(buffer.wait_for_anchors([text_anchor]))
1944                    });
1945                } else {
1946                    error = Some(anyhow!(
1947                        "buffer {:?} is not part of this multi-buffer",
1948                        text_anchor.buffer_id
1949                    ));
1950                    break;
1951                }
1952            }
1953        }
1954        async move {
1955            if let Some(error) = error {
1956                Err(error)?;
1957            }
1958            for future in futures {
1959                future.await?;
1960            }
1961            Ok(())
1962        }
1963    }
1964
1965    pub fn text_anchor_for_position<T: ToOffset>(
1966        &self,
1967        position: T,
1968        cx: &App,
1969    ) -> Option<(Entity<Buffer>, text::Anchor)> {
1970        let snapshot = self.read(cx);
1971        let anchor = snapshot.anchor_before(position).text_anchor()?;
1972        let buffer = self.buffers.get(&anchor.buffer_id.unwrap())?.buffer.clone();
1973        Some((buffer, anchor))
1974    }
1975
1976    fn on_buffer_event(
1977        &mut self,
1978        buffer: Entity<Buffer>,
1979        event: &language::BufferEvent,
1980        cx: &mut Context<Self>,
1981    ) {
1982        use language::BufferEvent;
1983        let buffer_id = buffer.read(cx).remote_id();
1984        cx.emit(match event {
1985            BufferEvent::Edited => Event::Edited {
1986                edited_buffer: Some(buffer),
1987            },
1988            BufferEvent::DirtyChanged => Event::DirtyChanged,
1989            BufferEvent::Saved => Event::Saved,
1990            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
1991            BufferEvent::Reloaded => Event::Reloaded,
1992            BufferEvent::LanguageChanged(has_language) => {
1993                Event::LanguageChanged(buffer_id, *has_language)
1994            }
1995            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
1996            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1997            BufferEvent::CapabilityChanged => {
1998                self.capability = buffer.read(cx).capability();
1999                return;
2000            }
2001            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2002        });
2003    }
2004
2005    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2006        let diff = diff.read(cx);
2007        let buffer_id = diff.buffer_id;
2008        let diff = DiffStateSnapshot {
2009            diff: diff.snapshot(cx),
2010            main_buffer: None,
2011        };
2012        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2013    }
2014
2015    fn inverted_buffer_diff_language_changed(
2016        &mut self,
2017        diff: Entity<BufferDiff>,
2018        main_buffer: Entity<language::Buffer>,
2019        cx: &mut Context<Self>,
2020    ) {
2021        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2022        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2023        let diff = diff.read(cx);
2024        let diff = DiffStateSnapshot {
2025            diff: diff.snapshot(cx),
2026            main_buffer: Some(main_buffer_snapshot),
2027        };
2028        self.snapshot
2029            .get_mut()
2030            .diffs
2031            .insert(base_text_buffer_id, diff);
2032    }
2033
2034    fn buffer_diff_changed(
2035        &mut self,
2036        diff: Entity<BufferDiff>,
2037        range: Range<text::Anchor>,
2038        cx: &mut Context<Self>,
2039    ) {
2040        self.sync_mut(cx);
2041
2042        let diff = diff.read(cx);
2043        let buffer_id = diff.buffer_id;
2044
2045        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2046            return;
2047        };
2048        let new_diff = DiffStateSnapshot {
2049            diff: diff.snapshot(cx),
2050            main_buffer: None,
2051        };
2052        let mut snapshot = self.snapshot.get_mut();
2053        let base_text_changed = snapshot
2054            .diffs
2055            .get(&buffer_id)
2056            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2057        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2058
2059        let buffer = buffer_state.buffer.read(cx);
2060        let diff_change_range = range.to_offset(buffer);
2061
2062        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2063        let edits = Self::sync_diff_transforms(
2064            &mut snapshot,
2065            excerpt_edits,
2066            DiffChangeKind::DiffUpdated {
2067                base_changed: base_text_changed,
2068            },
2069        );
2070        if !edits.is_empty() {
2071            self.subscriptions.publish(edits);
2072        }
2073        cx.emit(Event::Edited {
2074            edited_buffer: None,
2075        });
2076    }
2077
2078    fn inverted_buffer_diff_changed(
2079        &mut self,
2080        diff: Entity<BufferDiff>,
2081        main_buffer: Entity<language::Buffer>,
2082        diff_change_range: Option<Range<usize>>,
2083        cx: &mut Context<Self>,
2084    ) {
2085        self.sync_mut(cx);
2086
2087        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2088        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2089            return;
2090        };
2091
2092        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2093        let diff = diff.read(cx);
2094        let new_diff = DiffStateSnapshot {
2095            diff: diff.snapshot(cx),
2096            main_buffer: Some(main_buffer_snapshot),
2097        };
2098        let mut snapshot = self.snapshot.get_mut();
2099        snapshot
2100            .diffs
2101            .insert_or_replace(base_text_buffer_id, new_diff);
2102
2103        let Some(diff_change_range) = diff_change_range else {
2104            return;
2105        };
2106
2107        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2108        let edits = Self::sync_diff_transforms(
2109            &mut snapshot,
2110            excerpt_edits,
2111            DiffChangeKind::DiffUpdated {
2112                // We don't read this field for inverted diffs.
2113                base_changed: false,
2114            },
2115        );
2116        if !edits.is_empty() {
2117            self.subscriptions.publish(edits);
2118        }
2119        cx.emit(Event::Edited {
2120            edited_buffer: None,
2121        });
2122    }
2123
2124    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2125        self.buffers.values().map(|state| state.buffer.clone())
2126    }
2127
2128    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2129        self.all_buffers_iter().collect()
2130    }
2131
2132    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2133        self.buffers.keys().copied()
2134    }
2135
2136    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2137        self.all_buffer_ids_iter().collect()
2138    }
2139
2140    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2141        self.buffers
2142            .get(&buffer_id)
2143            .map(|state| state.buffer.clone())
2144    }
2145
2146    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2147        self.point_to_buffer_offset(point, cx)
2148            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2149    }
2150
2151    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2152        let buffer_id = self
2153            .snapshot
2154            .borrow()
2155            .excerpts
2156            .first()
2157            .map(|excerpt| excerpt.buffer.remote_id());
2158        buffer_id
2159            .and_then(|buffer_id| self.buffer(buffer_id))
2160            .map(|buffer| {
2161                let buffer = buffer.read(cx);
2162                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2163            })
2164            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2165    }
2166
2167    pub fn language_settings_at<'a, T: ToOffset>(
2168        &'a self,
2169        point: T,
2170        cx: &'a App,
2171    ) -> Cow<'a, LanguageSettings> {
2172        let mut language = None;
2173        let mut file = None;
2174        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2175            let buffer = buffer.read(cx);
2176            language = buffer.language_at(offset);
2177            file = buffer.file();
2178        }
2179        language_settings(language.map(|l| l.name()), file, cx)
2180    }
2181
2182    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2183        self.buffers.values().for_each(|state| f(&state.buffer))
2184    }
2185
2186    pub fn explicit_title(&self) -> Option<&str> {
2187        self.title.as_deref()
2188    }
2189
2190    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2191        if let Some(title) = self.title.as_ref() {
2192            return title.into();
2193        }
2194
2195        if let Some(buffer) = self.as_singleton() {
2196            let buffer = buffer.read(cx);
2197
2198            if let Some(file) = buffer.file() {
2199                return file.file_name(cx).into();
2200            }
2201
2202            if let Some(title) = self.buffer_content_title(buffer) {
2203                return title;
2204            }
2205        };
2206
2207        "untitled".into()
2208    }
2209
2210    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2211        let mut is_leading_whitespace = true;
2212        let mut count = 0;
2213        let mut prev_was_space = false;
2214        let mut title = String::new();
2215
2216        for ch in buffer.snapshot().chars() {
2217            if is_leading_whitespace && ch.is_whitespace() {
2218                continue;
2219            }
2220
2221            is_leading_whitespace = false;
2222
2223            if ch == '\n' || count >= 40 {
2224                break;
2225            }
2226
2227            if ch.is_whitespace() {
2228                if !prev_was_space {
2229                    title.push(' ');
2230                    count += 1;
2231                    prev_was_space = true;
2232                }
2233            } else {
2234                title.push(ch);
2235                count += 1;
2236                prev_was_space = false;
2237            }
2238        }
2239
2240        let title = title.trim_end().to_string();
2241
2242        if title.is_empty() {
2243            return None;
2244        }
2245
2246        Some(title.into())
2247    }
2248
2249    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2250        self.title = Some(title);
2251        cx.notify();
2252    }
2253
2254    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2255    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2256        for buffer_state in self.buffers.values() {
2257            buffer_state
2258                .buffer
2259                .update(cx, |buffer, _cx| buffer.refresh_preview());
2260        }
2261    }
2262
2263    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2264    pub fn preserve_preview(&self, cx: &App) -> bool {
2265        self.buffers
2266            .values()
2267            .all(|state| state.buffer.read(cx).preserve_preview())
2268    }
2269
2270    #[cfg(any(test, feature = "test-support"))]
2271    pub fn is_parsing(&self, cx: &App) -> bool {
2272        self.as_singleton().unwrap().read(cx).is_parsing()
2273    }
2274
2275    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2276        let buffer_id = diff.read(cx).buffer_id;
2277
2278        if let Some(existing_diff) = self.diff_for(buffer_id)
2279            && diff.entity_id() == existing_diff.entity_id()
2280        {
2281            return;
2282        }
2283
2284        self.buffer_diff_changed(
2285            diff.clone(),
2286            text::Anchor::min_max_range_for_buffer(buffer_id),
2287            cx,
2288        );
2289        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2290    }
2291
2292    pub fn add_inverted_diff(
2293        &mut self,
2294        diff: Entity<BufferDiff>,
2295        main_buffer: Entity<language::Buffer>,
2296        cx: &mut Context<Self>,
2297    ) {
2298        let snapshot = diff.read(cx).base_text(cx);
2299        let base_text_buffer_id = snapshot.remote_id();
2300        let diff_change_range = 0..snapshot.len();
2301        self.snapshot.get_mut().has_inverted_diff = true;
2302        self.inverted_buffer_diff_changed(
2303            diff.clone(),
2304            main_buffer.clone(),
2305            Some(diff_change_range),
2306            cx,
2307        );
2308        self.diffs.insert(
2309            base_text_buffer_id,
2310            DiffState::new_inverted(diff, main_buffer, cx),
2311        );
2312    }
2313
2314    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2315        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2316    }
2317
2318    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2319        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2320    }
2321
2322    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2323        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2324    }
2325
2326    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2327        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2328        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2329    }
2330
2331    pub fn all_diff_hunks_expanded(&self) -> bool {
2332        self.snapshot.borrow().all_diff_hunks_expanded
2333    }
2334
2335    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2336        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2337        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2338    }
2339
2340    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2341        self.snapshot.get_mut().show_deleted_hunks = show;
2342
2343        self.sync_mut(cx);
2344
2345        let old_len = self.snapshot.borrow().len();
2346
2347        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2348        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2349
2350        let new_len = self.snapshot.borrow().len();
2351
2352        self.subscriptions.publish(vec![Edit {
2353            old: MultiBufferOffset(0)..old_len,
2354            new: MultiBufferOffset(0)..new_len,
2355        }]);
2356
2357        cx.emit(Event::DiffHunksToggled);
2358        cx.emit(Event::Edited {
2359            edited_buffer: None,
2360        });
2361    }
2362
2363    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2364        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2365    }
2366
2367    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2368        self.read(cx)
2369            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2370            .nth(1)
2371            .is_some()
2372    }
2373
2374    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2375        let snapshot = self.read(cx);
2376        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2377        let offset_range = range.to_offset(&snapshot);
2378        cursor.seek(&offset_range.start, Bias::Left);
2379        while let Some(item) = cursor.item() {
2380            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2381                break;
2382            }
2383            if item.hunk_info().is_some() {
2384                return true;
2385            }
2386            cursor.next();
2387        }
2388        false
2389    }
2390
2391    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2392        let snapshot = self.read(cx);
2393        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2394        for range in ranges {
2395            let range = range.to_point(&snapshot);
2396            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2397            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2398                .min(snapshot.len());
2399            cursor.seek(&start, Bias::Right);
2400            while let Some(item) = cursor.item() {
2401                if *cursor.start() >= end {
2402                    break;
2403                }
2404                if item.hunk_info().is_some() {
2405                    return true;
2406                }
2407                cursor.next();
2408            }
2409        }
2410        false
2411    }
2412
2413    pub fn expand_or_collapse_diff_hunks_inner(
2414        &mut self,
2415        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2416        expand: bool,
2417        cx: &mut Context<Self>,
2418    ) -> Vec<Edit<MultiBufferOffset>> {
2419        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2420            return Vec::new();
2421        }
2422        self.sync_mut(cx);
2423        let mut snapshot = self.snapshot.get_mut();
2424        let mut excerpt_edits = Vec::new();
2425        let mut last_hunk_row = None;
2426        for (range, end_excerpt_id) in ranges {
2427            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2428                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2429                    continue;
2430                }
2431                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2432                    continue;
2433                }
2434                let start = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2435                let end = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2436                let start = snapshot.excerpt_offset_for_anchor(&start);
2437                let end = snapshot.excerpt_offset_for_anchor(&end);
2438                last_hunk_row = Some(diff_hunk.row_range.start);
2439                excerpt_edits.push(text::Edit {
2440                    old: start..end,
2441                    new: start..end,
2442                });
2443            }
2444        }
2445
2446        Self::sync_diff_transforms(
2447            &mut snapshot,
2448            excerpt_edits,
2449            DiffChangeKind::ExpandOrCollapseHunks { expand },
2450        )
2451    }
2452
2453    pub fn expand_or_collapse_diff_hunks(
2454        &mut self,
2455        ranges: Vec<Range<Anchor>>,
2456        expand: bool,
2457        cx: &mut Context<Self>,
2458    ) {
2459        let snapshot = self.snapshot.borrow().clone();
2460        let ranges = ranges.iter().map(move |range| {
2461            let end_excerpt_id = range.end.excerpt_id;
2462            let range = range.to_point(&snapshot);
2463            let mut peek_end = range.end;
2464            if range.end.row < snapshot.max_row().0 {
2465                peek_end = Point::new(range.end.row + 1, 0);
2466            };
2467            (range.start..peek_end, end_excerpt_id)
2468        });
2469        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2470        if !edits.is_empty() {
2471            self.subscriptions.publish(edits);
2472        }
2473        cx.emit(Event::DiffHunksToggled);
2474        cx.emit(Event::Edited {
2475            edited_buffer: None,
2476        });
2477    }
2478
2479    pub fn resize_excerpt(
2480        &mut self,
2481        id: ExcerptId,
2482        range: Range<text::Anchor>,
2483        cx: &mut Context<Self>,
2484    ) {
2485        self.sync_mut(cx);
2486
2487        let mut snapshot = self.snapshot.get_mut();
2488        let locator = snapshot.excerpt_locator_for_id(id);
2489        let mut new_excerpts = SumTree::default();
2490        let mut cursor = snapshot
2491            .excerpts
2492            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2493        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2494
2495        let prefix = cursor.slice(&Some(locator), Bias::Left);
2496        new_excerpts.append(prefix, ());
2497
2498        let mut excerpt = cursor.item().unwrap().clone();
2499        let old_text_len = excerpt.text_summary.len;
2500
2501        excerpt.range.context.start = range.start;
2502        excerpt.range.context.end = range.end;
2503        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2504
2505        excerpt.text_summary = excerpt
2506            .buffer
2507            .text_summary_for_range(excerpt.range.context.clone());
2508
2509        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2510        let old_start_offset = cursor.start().1;
2511        let new_text_len = excerpt.text_summary.len;
2512        let edit = Edit {
2513            old: old_start_offset..old_start_offset + old_text_len,
2514            new: new_start_offset..new_start_offset + new_text_len,
2515        };
2516
2517        if let Some(last_edit) = edits.last_mut() {
2518            if last_edit.old.end == edit.old.start {
2519                last_edit.old.end = edit.old.end;
2520                last_edit.new.end = edit.new.end;
2521            } else {
2522                edits.push(edit);
2523            }
2524        } else {
2525            edits.push(edit);
2526        }
2527
2528        new_excerpts.push(excerpt, ());
2529
2530        cursor.next();
2531
2532        new_excerpts.append(cursor.suffix(), ());
2533
2534        drop(cursor);
2535        snapshot.excerpts = new_excerpts;
2536
2537        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2538        if !edits.is_empty() {
2539            self.subscriptions.publish(edits);
2540        }
2541        cx.emit(Event::Edited {
2542            edited_buffer: None,
2543        });
2544        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2545        cx.notify();
2546    }
2547
2548    pub fn expand_excerpts(
2549        &mut self,
2550        ids: impl IntoIterator<Item = ExcerptId>,
2551        line_count: u32,
2552        direction: ExpandExcerptDirection,
2553        cx: &mut Context<Self>,
2554    ) {
2555        if line_count == 0 {
2556            return;
2557        }
2558        self.sync_mut(cx);
2559        if !self.excerpts_by_path.is_empty() {
2560            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2561            return;
2562        }
2563        let mut snapshot = self.snapshot.get_mut();
2564
2565        let ids = ids.into_iter().collect::<Vec<_>>();
2566        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2567        let mut new_excerpts = SumTree::default();
2568        let mut cursor = snapshot
2569            .excerpts
2570            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2571        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2572
2573        for locator in &locators {
2574            let prefix = cursor.slice(&Some(locator), Bias::Left);
2575            new_excerpts.append(prefix, ());
2576
2577            let mut excerpt = cursor.item().unwrap().clone();
2578            let old_text_len = excerpt.text_summary.len;
2579
2580            let up_line_count = if direction.should_expand_up() {
2581                line_count
2582            } else {
2583                0
2584            };
2585
2586            let start_row = excerpt
2587                .range
2588                .context
2589                .start
2590                .to_point(&excerpt.buffer)
2591                .row
2592                .saturating_sub(up_line_count);
2593            let start_point = Point::new(start_row, 0);
2594            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2595
2596            let down_line_count = if direction.should_expand_down() {
2597                line_count
2598            } else {
2599                0
2600            };
2601
2602            let mut end_point = excerpt.buffer.clip_point(
2603                excerpt.range.context.end.to_point(&excerpt.buffer)
2604                    + Point::new(down_line_count, 0),
2605                Bias::Left,
2606            );
2607            end_point.column = excerpt.buffer.line_len(end_point.row);
2608            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2609            excerpt.max_buffer_row = end_point.row;
2610
2611            excerpt.text_summary = excerpt
2612                .buffer
2613                .text_summary_for_range(excerpt.range.context.clone());
2614
2615            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2616            let old_start_offset = cursor.start().1;
2617            let new_text_len = excerpt.text_summary.len;
2618            let edit = Edit {
2619                old: old_start_offset..old_start_offset + old_text_len,
2620                new: new_start_offset..new_start_offset + new_text_len,
2621            };
2622
2623            if let Some(last_edit) = edits.last_mut() {
2624                if last_edit.old.end == edit.old.start {
2625                    last_edit.old.end = edit.old.end;
2626                    last_edit.new.end = edit.new.end;
2627                } else {
2628                    edits.push(edit);
2629                }
2630            } else {
2631                edits.push(edit);
2632            }
2633
2634            new_excerpts.push(excerpt, ());
2635
2636            cursor.next();
2637        }
2638
2639        new_excerpts.append(cursor.suffix(), ());
2640
2641        drop(cursor);
2642        snapshot.excerpts = new_excerpts;
2643
2644        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2645        if !edits.is_empty() {
2646            self.subscriptions.publish(edits);
2647        }
2648        cx.emit(Event::Edited {
2649            edited_buffer: None,
2650        });
2651        cx.emit(Event::ExcerptsExpanded { ids });
2652        cx.notify();
2653    }
2654
2655    #[ztracing::instrument(skip_all)]
2656    fn sync(&self, cx: &App) {
2657        let changed = self.buffer_changed_since_sync.replace(false);
2658        if !changed {
2659            return;
2660        }
2661        let edits = Self::sync_from_buffer_changes(
2662            &mut self.snapshot.borrow_mut(),
2663            &self.buffers,
2664            &self.diffs,
2665            cx,
2666        );
2667        if !edits.is_empty() {
2668            self.subscriptions.publish(edits);
2669        }
2670    }
2671
2672    fn sync_mut(&mut self, cx: &App) {
2673        let changed = self.buffer_changed_since_sync.replace(false);
2674        if !changed {
2675            return;
2676        }
2677        let edits =
2678            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2679
2680        if !edits.is_empty() {
2681            self.subscriptions.publish(edits);
2682        }
2683    }
2684
2685    fn sync_from_buffer_changes(
2686        snapshot: &mut MultiBufferSnapshot,
2687        buffers: &BTreeMap<BufferId, BufferState>,
2688        diffs: &HashMap<BufferId, DiffState>,
2689        cx: &App,
2690    ) -> Vec<Edit<MultiBufferOffset>> {
2691        let MultiBufferSnapshot {
2692            excerpts,
2693            diffs: buffer_diff,
2694            path_keys_by_buffer,
2695            path_keys_by_index,
2696            diff_transforms: _,
2697            non_text_state_update_count,
2698            edit_count,
2699            is_dirty,
2700            has_deleted_file,
2701            has_conflict,
2702            has_inverted_diff: _,
2703            singleton: _,
2704            trailing_excerpt_update_count: _,
2705            all_diff_hunks_expanded: _,
2706            show_deleted_hunks: _,
2707            use_extended_diff_range: _,
2708            show_headers: _,
2709        } = snapshot;
2710        *is_dirty = false;
2711        *has_deleted_file = false;
2712        *has_conflict = false;
2713
2714        if !diffs.is_empty() {
2715            let mut diffs_to_add = Vec::new();
2716            for (id, diff) in diffs {
2717                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2718                // and use the diff hunk base text ranges to compute diff transforms.
2719                // Those base text ranges are usize, so make sure if the base text changed
2720                // we also update the diff snapshot so that we don't use stale offsets
2721                if buffer_diff.get(id).is_none_or(|existing_diff| {
2722                    if existing_diff.main_buffer.is_none() {
2723                        return false;
2724                    }
2725                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2726                    base_text.remote_id() != existing_diff.base_text().remote_id()
2727                        || base_text
2728                            .version()
2729                            .changed_since(existing_diff.base_text().version())
2730                }) {
2731                    if diffs_to_add.capacity() == 0 {
2732                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2733                        // meaning re-allocations will be fairly expensive
2734                        diffs_to_add.reserve(diffs.len());
2735                    }
2736                    diffs_to_add.push((*id, diff.snapshot(cx)));
2737                }
2738            }
2739            buffer_diff.extend(diffs_to_add);
2740        }
2741
2742        let mut paths_to_edit = Vec::new();
2743        let mut non_text_state_updated = false;
2744        let mut edited = false;
2745        for buffer_state in buffers.values() {
2746            let buffer = buffer_state.buffer.read(cx);
2747            let version = buffer.version();
2748            let non_text_state_update_count = buffer.non_text_state_update_count();
2749
2750            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2751            let buffer_non_text_state_updated =
2752                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2753            if (buffer_edited || buffer_non_text_state_updated)
2754                && let Some(path_key) = path_keys_by_buffer.get(&buffer.remote_id())
2755            {
2756                *buffer_state.last_version.borrow_mut() = version;
2757                buffer_state
2758                    .last_non_text_state_update_count
2759                    .set(non_text_state_update_count);
2760                paths_to_edit.push((path_key.clone(), buffer_state.buffer.clone(), buffer_edited));
2761            }
2762
2763            edited |= buffer_edited;
2764            non_text_state_updated |= buffer_non_text_state_updated;
2765            *is_dirty |= buffer.is_dirty();
2766            *has_deleted_file |= buffer
2767                .file()
2768                .is_some_and(|file| file.disk_state().is_deleted());
2769            *has_conflict |= buffer.has_conflict();
2770        }
2771        if edited {
2772            *edit_count += 1;
2773        }
2774        if non_text_state_updated {
2775            *non_text_state_update_count += 1;
2776        }
2777
2778        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path);
2779
2780        let mut edits = Vec::new();
2781        let mut new_excerpts = SumTree::default();
2782        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2783
2784        for (path, buffer, buffer_edited) in paths_to_edit {
2785            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2786            let old_excerpt = cursor.item().unwrap();
2787            let buffer = buffer.read(cx);
2788            let buffer_id = buffer.remote_id();
2789            let mut new_excerpt;
2790            if buffer_edited {
2791                edits.extend(
2792                    buffer
2793                        .edits_since_in_range::<usize>(
2794                            old_excerpt.buffer.version(),
2795                            old_excerpt.range.context.clone(),
2796                        )
2797                        .map(|edit| {
2798                            let excerpt_old_start = cursor.start().1;
2799                            let excerpt_new_start =
2800                                ExcerptDimension(new_excerpts.summary().text.len);
2801                            let old_start = excerpt_old_start + edit.old.start;
2802                            let old_end = excerpt_old_start + edit.old.end;
2803                            let new_start = excerpt_new_start + edit.new.start;
2804                            let new_end = excerpt_new_start + edit.new.end;
2805                            Edit {
2806                                old: old_start..old_end,
2807                                new: new_start..new_end,
2808                            }
2809                        }),
2810                );
2811
2812                new_excerpt = Excerpt::new(
2813                    path,
2814                    Arc::new(buffer.snapshot()),
2815                    old_excerpt.range.clone(),
2816                    old_excerpt.has_trailing_newline,
2817                );
2818            } else {
2819                new_excerpt = old_excerpt.clone();
2820                new_excerpt.buffer = Arc::new(buffer.snapshot());
2821            }
2822
2823            new_excerpts.push(new_excerpt, ());
2824            cursor.next();
2825        }
2826        new_excerpts.append(cursor.suffix(), ());
2827
2828        drop(cursor);
2829        *excerpts = new_excerpts;
2830
2831        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2832    }
2833
2834    fn sync_diff_transforms(
2835        snapshot: &mut MultiBufferSnapshot,
2836        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2837        change_kind: DiffChangeKind,
2838    ) -> Vec<Edit<MultiBufferOffset>> {
2839        if excerpt_edits.is_empty() {
2840            return vec![];
2841        }
2842
2843        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2844        let mut old_diff_transforms = snapshot
2845            .diff_transforms
2846            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2847        let mut new_diff_transforms = SumTree::default();
2848        let mut old_expanded_hunks = HashSet::default();
2849        let mut output_edits = Vec::new();
2850        let mut output_delta = 0_isize;
2851        let mut at_transform_boundary = true;
2852        let mut end_of_current_insert = None;
2853
2854        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2855        while let Some(edit) = excerpt_edits.next() {
2856            excerpts.seek_forward(&edit.new.start, Bias::Right);
2857            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2858                excerpts.prev();
2859            }
2860
2861            // Keep any transforms that are before the edit.
2862            if at_transform_boundary {
2863                at_transform_boundary = false;
2864                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2865                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2866                if let Some(transform) = old_diff_transforms.item()
2867                    && old_diff_transforms.end().0 == edit.old.start
2868                    && old_diff_transforms.start().0 < edit.old.start
2869                {
2870                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2871                    old_diff_transforms.next();
2872                }
2873            }
2874
2875            // Compute the start of the edit in output coordinates.
2876            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2877            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2878            let edit_new_start =
2879                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2880
2881            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2882                &edit,
2883                &mut excerpts,
2884                &mut old_diff_transforms,
2885                &mut new_diff_transforms,
2886                &mut end_of_current_insert,
2887                &mut old_expanded_hunks,
2888                snapshot,
2889                change_kind,
2890            );
2891
2892            // Compute the end of the edit in output coordinates.
2893            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2894            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2895            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2896            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2897            let output_edit = Edit {
2898                old: edit_old_start..edit_old_end,
2899                new: edit_new_start..edit_new_end,
2900            };
2901
2902            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2903            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2904            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2905                output_edits.push(output_edit);
2906            }
2907
2908            // If this is the last edit that intersects the current diff transform,
2909            // then recreate the content up to the end of this transform, to prepare
2910            // for reusing additional slices of the old transforms.
2911            if excerpt_edits
2912                .peek()
2913                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2914            {
2915                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2916                    && match old_diff_transforms.item() {
2917                        Some(DiffTransform::BufferContent {
2918                            inserted_hunk_info: Some(hunk),
2919                            ..
2920                        }) => excerpts.item().is_some_and(|excerpt| {
2921                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2922                                && diff.main_buffer.is_some()
2923                            {
2924                                return true;
2925                            }
2926                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2927                        }),
2928                        _ => true,
2929                    };
2930
2931                let mut excerpt_offset = edit.new.end;
2932                if !keep_next_old_transform {
2933                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2934                    old_diff_transforms.next();
2935                }
2936
2937                old_expanded_hunks.clear();
2938                Self::push_buffer_content_transform(
2939                    snapshot,
2940                    &mut new_diff_transforms,
2941                    excerpt_offset,
2942                    end_of_current_insert,
2943                );
2944                at_transform_boundary = true;
2945            }
2946        }
2947
2948        // Keep any transforms that are after the last edit.
2949        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2950
2951        // Ensure there's always at least one buffer content transform.
2952        if new_diff_transforms.is_empty() {
2953            new_diff_transforms.push(
2954                DiffTransform::BufferContent {
2955                    summary: Default::default(),
2956                    inserted_hunk_info: None,
2957                },
2958                (),
2959            );
2960        }
2961
2962        drop(old_diff_transforms);
2963        drop(excerpts);
2964        snapshot.diff_transforms = new_diff_transforms;
2965        snapshot.edit_count += 1;
2966
2967        #[cfg(any(test, feature = "test-support"))]
2968        snapshot.check_invariants();
2969        output_edits
2970    }
2971
2972    fn recompute_diff_transforms_for_edit(
2973        edit: &Edit<ExcerptOffset>,
2974        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2975        old_diff_transforms: &mut Cursor<
2976            DiffTransform,
2977            Dimensions<ExcerptOffset, MultiBufferOffset>,
2978        >,
2979        new_diff_transforms: &mut SumTree<DiffTransform>,
2980        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2981        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2982        snapshot: &MultiBufferSnapshot,
2983        change_kind: DiffChangeKind,
2984    ) -> bool {
2985        log::trace!(
2986            "recomputing diff transform for edit {:?} => {:?}",
2987            edit.old.start..edit.old.end,
2988            edit.new.start..edit.new.end
2989        );
2990
2991        // Record which hunks were previously expanded.
2992        while let Some(item) = old_diff_transforms.item() {
2993            if let Some(hunk_info) = item.hunk_info() {
2994                log::trace!(
2995                    "previously expanded hunk at {:?}",
2996                    old_diff_transforms.start()
2997                );
2998                old_expanded_hunks.insert(hunk_info);
2999            }
3000            if old_diff_transforms.end().0 > edit.old.end {
3001                break;
3002            }
3003            old_diff_transforms.next();
3004        }
3005
3006        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3007        // For inverted diffs, hunks are always shown, so we can't skip this.
3008        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3009        if old_expanded_hunks.is_empty()
3010            && change_kind == DiffChangeKind::BufferEdited
3011            && !all_diff_hunks_expanded
3012            && !snapshot.has_inverted_diff
3013        {
3014            return false;
3015        }
3016
3017        // Visit each excerpt that intersects the edit.
3018        let mut did_expand_hunks = false;
3019        while let Some(excerpt) = excerpts.item() {
3020            // Recompute the expanded hunks in the portion of the excerpt that
3021            // intersects the edit.
3022            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3023                let buffer = &excerpt.buffer;
3024                let excerpt_start = *excerpts.start();
3025                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3026                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3027                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3028                let edit_buffer_start =
3029                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3030                let edit_buffer_end =
3031                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3032                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3033
3034                if let Some(main_buffer) = &diff.main_buffer {
3035                    for hunk in diff.hunks_intersecting_base_text_range(
3036                        edit_buffer_start..edit_buffer_end,
3037                        main_buffer,
3038                    ) {
3039                        did_expand_hunks = true;
3040                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3041                        if hunk_buffer_range.start < excerpt_buffer_start {
3042                            log::trace!("skipping hunk that starts before excerpt");
3043                            continue;
3044                        }
3045                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3046                        let hunk_excerpt_start = excerpt_start
3047                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3048                        let hunk_excerpt_end = excerpt_end
3049                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3050                        Self::push_buffer_content_transform(
3051                            snapshot,
3052                            new_diff_transforms,
3053                            hunk_excerpt_start,
3054                            *end_of_current_insert,
3055                        );
3056                        if !hunk_buffer_range.is_empty() {
3057                            let hunk_info = DiffTransformHunkInfo {
3058                                excerpt_id: excerpt.id,
3059                                hunk_start_anchor: hunk.buffer_range.start,
3060                                hunk_secondary_status: hunk.secondary_status,
3061                                is_logically_deleted: true,
3062                            };
3063                            *end_of_current_insert =
3064                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3065                        }
3066                    }
3067                } else {
3068                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3069                        ..buffer.anchor_after(edit_buffer_end);
3070                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3071                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3072                            continue;
3073                        }
3074
3075                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3076                        if hunk_buffer_range.start < excerpt_buffer_start {
3077                            log::trace!("skipping hunk that starts before excerpt");
3078                            continue;
3079                        }
3080
3081                        let hunk_info = DiffTransformHunkInfo {
3082                            excerpt_id: excerpt.id,
3083                            hunk_start_anchor: hunk.buffer_range.start,
3084                            hunk_secondary_status: hunk.secondary_status,
3085                            is_logically_deleted: false,
3086                        };
3087
3088                        let hunk_excerpt_start = excerpt_start
3089                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3090                        let hunk_excerpt_end = excerpt_end
3091                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3092
3093                        Self::push_buffer_content_transform(
3094                            snapshot,
3095                            new_diff_transforms,
3096                            hunk_excerpt_start,
3097                            *end_of_current_insert,
3098                        );
3099
3100                        // For every existing hunk, determine if it was previously expanded
3101                        // and if it should currently be expanded.
3102                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3103                        let should_expand_hunk = match &change_kind {
3104                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3105                                was_previously_expanded || all_diff_hunks_expanded
3106                            }
3107                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3108                                let intersects = hunk_buffer_range.is_empty()
3109                                    || hunk_buffer_range.end > edit_buffer_start;
3110                                if *expand {
3111                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3112                                } else {
3113                                    !intersects
3114                                        && (was_previously_expanded || all_diff_hunks_expanded)
3115                                }
3116                            }
3117                            _ => was_previously_expanded || all_diff_hunks_expanded,
3118                        };
3119
3120                        if should_expand_hunk {
3121                            did_expand_hunks = true;
3122                            log::trace!(
3123                                "expanding hunk {:?}, excerpt:{:?}",
3124                                hunk_excerpt_start..hunk_excerpt_end,
3125                                excerpt.id
3126                            );
3127
3128                            if !hunk.diff_base_byte_range.is_empty()
3129                                && hunk_buffer_range.start >= edit_buffer_start
3130                                && hunk_buffer_range.start <= excerpt_buffer_end
3131                                && snapshot.show_deleted_hunks
3132                            {
3133                                let base_text = diff.base_text();
3134                                let mut text_cursor =
3135                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3136                                let mut base_text_summary = text_cursor
3137                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3138
3139                                let mut has_trailing_newline = false;
3140                                if base_text_summary.last_line_chars > 0 {
3141                                    base_text_summary += TextSummary::newline();
3142                                    has_trailing_newline = true;
3143                                }
3144
3145                                new_diff_transforms.push(
3146                                    DiffTransform::DeletedHunk {
3147                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3148                                        summary: base_text_summary,
3149                                        buffer_id: excerpt.buffer_id,
3150                                        hunk_info,
3151                                        has_trailing_newline,
3152                                    },
3153                                    (),
3154                                );
3155                            }
3156
3157                            if !hunk_buffer_range.is_empty() {
3158                                *end_of_current_insert =
3159                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3160                            }
3161                        }
3162                    }
3163                }
3164            }
3165
3166            if excerpts.end() <= edit.new.end {
3167                excerpts.next();
3168            } else {
3169                break;
3170            }
3171        }
3172
3173        did_expand_hunks || !old_expanded_hunks.is_empty()
3174    }
3175
3176    fn append_diff_transforms(
3177        new_transforms: &mut SumTree<DiffTransform>,
3178        subtree: SumTree<DiffTransform>,
3179    ) {
3180        if let Some(DiffTransform::BufferContent {
3181            inserted_hunk_info,
3182            summary,
3183        }) = subtree.first()
3184            && Self::extend_last_buffer_content_transform(
3185                new_transforms,
3186                *inserted_hunk_info,
3187                *summary,
3188            )
3189        {
3190            let mut cursor = subtree.cursor::<()>(());
3191            cursor.next();
3192            cursor.next();
3193            new_transforms.append(cursor.suffix(), ());
3194            return;
3195        }
3196        new_transforms.append(subtree, ());
3197    }
3198
3199    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3200        if let DiffTransform::BufferContent {
3201            inserted_hunk_info: inserted_hunk_anchor,
3202            summary,
3203        } = transform
3204            && Self::extend_last_buffer_content_transform(
3205                new_transforms,
3206                inserted_hunk_anchor,
3207                summary,
3208            )
3209        {
3210            return;
3211        }
3212        new_transforms.push(transform, ());
3213    }
3214
3215    fn push_buffer_content_transform(
3216        old_snapshot: &MultiBufferSnapshot,
3217        new_transforms: &mut SumTree<DiffTransform>,
3218        end_offset: ExcerptOffset,
3219        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3220    ) {
3221        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3222            (end_offset.min(insertion_end_offset), Some(hunk_info))
3223        });
3224        let unchanged_region = [(end_offset, None)];
3225
3226        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3227        {
3228            let start_offset = new_transforms.summary().excerpt_len();
3229            if end_offset <= start_offset {
3230                continue;
3231            }
3232            let summary_to_add = old_snapshot
3233                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3234
3235            if !Self::extend_last_buffer_content_transform(
3236                new_transforms,
3237                inserted_hunk_info,
3238                summary_to_add,
3239            ) {
3240                new_transforms.push(
3241                    DiffTransform::BufferContent {
3242                        summary: summary_to_add,
3243                        inserted_hunk_info,
3244                    },
3245                    (),
3246                )
3247            }
3248        }
3249    }
3250
3251    fn extend_last_buffer_content_transform(
3252        new_transforms: &mut SumTree<DiffTransform>,
3253        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3254        summary_to_add: MBTextSummary,
3255    ) -> bool {
3256        let mut did_extend = false;
3257        new_transforms.update_last(
3258            |last_transform| {
3259                if let DiffTransform::BufferContent {
3260                    summary,
3261                    inserted_hunk_info: inserted_hunk_anchor,
3262                } = last_transform
3263                    && *inserted_hunk_anchor == new_inserted_hunk_info
3264                {
3265                    *summary += summary_to_add;
3266                    did_extend = true;
3267                }
3268            },
3269            (),
3270        );
3271        did_extend
3272    }
3273
3274    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3275        let snapshot = self.snapshot(cx);
3276        let excerpt_id = range.end.excerpt_id;
3277        let point_range = range.to_point(&snapshot);
3278        let expand = !self.single_hunk_is_expanded(range, cx);
3279        let edits =
3280            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3281        if !edits.is_empty() {
3282            self.subscriptions.publish(edits);
3283        }
3284        cx.emit(Event::DiffHunksToggled);
3285        cx.emit(Event::Edited {
3286            edited_buffer: None,
3287        });
3288    }
3289}
3290
3291fn build_excerpt_ranges(
3292    ranges: impl IntoIterator<Item = Range<Point>>,
3293    context_line_count: u32,
3294    buffer_snapshot: &BufferSnapshot,
3295) -> Vec<ExcerptRange<Point>> {
3296    ranges
3297        .into_iter()
3298        .map(|range| {
3299            let start_row = range.start.row.saturating_sub(context_line_count);
3300            let start = Point::new(start_row, 0);
3301            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3302            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3303            ExcerptRange {
3304                context: start..end,
3305                primary: range,
3306            }
3307        })
3308        .collect()
3309}
3310
3311#[cfg(any(test, feature = "test-support"))]
3312impl MultiBuffer {
3313    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3314        let buffer = cx.new(|cx| Buffer::local(text, cx));
3315        cx.new(|cx| Self::singleton(buffer, cx))
3316    }
3317
3318    pub fn build_multi<const COUNT: usize>(
3319        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3320        cx: &mut gpui::App,
3321    ) -> Entity<Self> {
3322        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3323        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3324            let buffer = cx.new(|cx| Buffer::local(text, cx));
3325            let snapshot = buffer.read(cx).snapshot();
3326            let excerpt_ranges = ranges
3327                .into_iter()
3328                .map(ExcerptRange::new)
3329                .collect::<Vec<_>>();
3330            multi.update(cx, |multi, cx| {
3331                multi.set_excerpt_ranges_for_path(
3332                    PathKey::sorted(ix as u64),
3333                    buffer,
3334                    &snapshot,
3335                    excerpt_ranges,
3336                    cx,
3337                )
3338            });
3339        }
3340
3341        multi
3342    }
3343
3344    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3345        cx.new(|cx| Self::singleton(buffer, cx))
3346    }
3347
3348    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3349        cx.new(|cx| {
3350            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3351            let mutation_count = rng.random_range(1..=5);
3352            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3353            multibuffer
3354        })
3355    }
3356
3357    pub fn randomly_edit(
3358        &mut self,
3359        rng: &mut impl rand::Rng,
3360        edit_count: usize,
3361        cx: &mut Context<Self>,
3362    ) {
3363        use util::RandomCharIter;
3364
3365        let snapshot = self.read(cx);
3366        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3367        let mut last_end = None;
3368        for _ in 0..edit_count {
3369            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3370                break;
3371            }
3372
3373            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3374            let end =
3375                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3376            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3377            last_end = Some(end);
3378
3379            let mut range = start..end;
3380            if rng.random_bool(0.2) {
3381                mem::swap(&mut range.start, &mut range.end);
3382            }
3383
3384            let new_text_len = rng.random_range(0..10);
3385            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3386
3387            edits.push((range, new_text.into()));
3388        }
3389        log::info!("mutating multi-buffer with {:?}", edits);
3390        drop(snapshot);
3391
3392        self.edit(edits, None, cx);
3393    }
3394
3395    pub fn randomly_edit_excerpts(
3396        &mut self,
3397        rng: &mut impl rand::Rng,
3398        mutation_count: usize,
3399        cx: &mut Context<Self>,
3400    ) {
3401        use rand::prelude::*;
3402        use std::env;
3403        use util::RandomCharIter;
3404
3405        let max_excerpts = env::var("MAX_EXCERPTS")
3406            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3407            .unwrap_or(5);
3408
3409        let mut buffers = Vec::new();
3410        for _ in 0..mutation_count {
3411            if rng.random_bool(0.05) {
3412                log::info!("Clearing multi-buffer");
3413                self.clear(cx);
3414                continue;
3415            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3416                let ids = self.excerpt_ids();
3417                let mut excerpts = HashSet::default();
3418                for _ in 0..rng.random_range(0..ids.len()) {
3419                    excerpts.extend(ids.choose(rng).copied());
3420                }
3421
3422                let line_count = rng.random_range(0..5);
3423
3424                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3425
3426                self.expand_excerpts(
3427                    excerpts.iter().cloned(),
3428                    line_count,
3429                    ExpandExcerptDirection::UpAndDown,
3430                    cx,
3431                );
3432                continue;
3433            }
3434
3435            let excerpt_ids = self.excerpt_ids();
3436            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3437                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3438                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3439                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3440                    let buffer = buffers.last().unwrap().read(cx);
3441                    log::info!(
3442                        "Creating new buffer {} with text: {:?}",
3443                        buffer.remote_id(),
3444                        buffer.text()
3445                    );
3446                    buffers.last().unwrap().clone()
3447                } else {
3448                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3449                };
3450
3451                let buffer = buffer_handle.read(cx);
3452                let buffer_text = buffer.text();
3453                let ranges = (0..rng.random_range(0..5))
3454                    .map(|_| {
3455                        let end_ix =
3456                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3457                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3458                        ExcerptRange::new(start_ix..end_ix)
3459                    })
3460                    .collect::<Vec<_>>();
3461                log::info!(
3462                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3463                    buffer_handle.read(cx).remote_id(),
3464                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3465                    ranges
3466                        .iter()
3467                        .map(|r| &buffer_text[r.context.clone()])
3468                        .collect::<Vec<_>>()
3469                );
3470
3471                let excerpt_id =
3472                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3473                log::info!("Inserted with ids: {:?}", excerpt_id);
3474            } else {
3475                let remove_count = rng.random_range(1..=excerpt_ids.len());
3476                let mut excerpts_to_remove = excerpt_ids
3477                    .choose_multiple(rng, remove_count)
3478                    .cloned()
3479                    .collect::<Vec<_>>();
3480                let snapshot = self.snapshot.borrow();
3481                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3482                drop(snapshot);
3483                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3484                self.remove_excerpts(excerpts_to_remove, cx);
3485            }
3486        }
3487    }
3488
3489    pub fn randomly_mutate(
3490        &mut self,
3491        rng: &mut impl rand::Rng,
3492        mutation_count: usize,
3493        cx: &mut Context<Self>,
3494    ) {
3495        use rand::prelude::*;
3496
3497        if rng.random_bool(0.7) || self.singleton {
3498            let buffer = self
3499                .buffers
3500                .values()
3501                .choose(rng)
3502                .map(|state| state.buffer.clone());
3503
3504            if let Some(buffer) = buffer {
3505                buffer.update(cx, |buffer, cx| {
3506                    if rng.random() {
3507                        buffer.randomly_edit(rng, mutation_count, cx);
3508                    } else {
3509                        buffer.randomly_undo_redo(rng, cx);
3510                    }
3511                });
3512            } else {
3513                self.randomly_edit(rng, mutation_count, cx);
3514            }
3515        } else {
3516            self.randomly_edit_excerpts(rng, mutation_count, cx);
3517        }
3518
3519        self.check_invariants(cx);
3520    }
3521
3522    fn check_invariants(&self, cx: &App) {
3523        self.read(cx).check_invariants();
3524    }
3525}
3526
3527impl EventEmitter<Event> for MultiBuffer {}
3528
3529impl MultiBufferSnapshot {
3530    pub fn text(&self) -> String {
3531        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3532            .map(|chunk| chunk.text)
3533            .collect()
3534    }
3535
3536    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3537        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3538            .flat_map(|c| c.chars().rev())
3539    }
3540
3541    fn reversed_chunks_in_range(
3542        &self,
3543        range: Range<MultiBufferOffset>,
3544    ) -> ReversedMultiBufferChunks<'_> {
3545        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3546        cursor.seek(&range.end);
3547        let current_chunks = cursor.region().as_ref().map(|region| {
3548            let start_overshoot = range.start.saturating_sub(region.range.start);
3549            let end_overshoot = range.end - region.range.start;
3550            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3551            let start = region.buffer_range.start + start_overshoot;
3552            region.buffer.reversed_chunks_in_range(start..end)
3553        });
3554        ReversedMultiBufferChunks {
3555            cursor,
3556            current_chunks,
3557            start: range.start,
3558            offset: range.end,
3559        }
3560    }
3561
3562    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3563        let offset = position.to_offset(self);
3564        self.text_for_range(offset..self.len())
3565            .flat_map(|chunk| chunk.chars())
3566    }
3567
3568    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3569        self.chunks(range, false).map(|chunk| chunk.text)
3570    }
3571
3572    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3573        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3574            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3575    }
3576
3577    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3578    where
3579        T: ToOffset,
3580    {
3581        let position = position.to_offset(self);
3582        position == self.clip_offset(position, Bias::Left)
3583            && self
3584                .bytes_in_range(position..self.len())
3585                .flatten()
3586                .copied()
3587                .take(needle.len())
3588                .eq(needle.bytes())
3589    }
3590
3591    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3592        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3593    }
3594
3595    pub fn diff_hunks_in_range<T: ToPoint>(
3596        &self,
3597        range: Range<T>,
3598    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3599        let query_range = range.start.to_point(self)..range.end.to_point(self);
3600        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3601            let diff = self.diffs.get(&buffer.remote_id())?;
3602            let iter = if let Some(main_buffer) = &diff.main_buffer {
3603                let buffer_start = buffer.point_to_offset(buffer_range.start);
3604                let buffer_end = buffer.point_to_offset(buffer_range.end);
3605                itertools::Either::Left(
3606                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3607                        .map(move |hunk| (hunk, buffer, true)),
3608                )
3609            } else {
3610                let buffer_start = buffer.anchor_before(buffer_range.start);
3611                let buffer_end = buffer.anchor_after(buffer_range.end);
3612                itertools::Either::Right(
3613                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3614                        .map(move |hunk| (hunk, buffer, false)),
3615                )
3616            };
3617            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3618                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3619                    return None;
3620                }
3621                let range = if is_inverted {
3622                    hunk.diff_base_byte_range.to_point(&buffer)
3623                } else {
3624                    hunk.range.clone()
3625                };
3626                Some((range, (hunk, is_inverted)))
3627            }))
3628        })
3629        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3630            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3631            {
3632                return None;
3633            }
3634            let end_row = if range.end.column == 0 {
3635                range.end.row
3636            } else {
3637                range.end.row + 1
3638            };
3639
3640            let word_diffs =
3641                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3642                    .then(|| {
3643                        let mut word_diffs = Vec::new();
3644
3645                        if self.show_deleted_hunks || is_inverted {
3646                            let hunk_start_offset = if is_inverted {
3647                                Anchor::text(
3648                                    excerpt.id,
3649                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3650                                )
3651                                .to_offset(self)
3652                            } else {
3653                                Anchor::text(excerpt.id, hunk.buffer_range.start).to_offset(self)
3654                            };
3655
3656                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3657                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3658                            }));
3659                        }
3660
3661                        if !is_inverted {
3662                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3663                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3664                            }));
3665                        }
3666                        word_diffs
3667                    })
3668                    .unwrap_or_default();
3669
3670            let buffer_range = if is_inverted {
3671                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3672                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3673            } else {
3674                hunk.buffer_range.clone()
3675            };
3676            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3677                DiffHunkStatusKind::Deleted
3678            } else if hunk.diff_base_byte_range.is_empty() {
3679                DiffHunkStatusKind::Added
3680            } else {
3681                DiffHunkStatusKind::Modified
3682            };
3683            Some(MultiBufferDiffHunk {
3684                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3685                buffer_id: excerpt.buffer_id,
3686                excerpt_id: excerpt.id,
3687                buffer_range,
3688                word_diffs,
3689                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3690                    ..BufferOffset(hunk.diff_base_byte_range.end),
3691                status: DiffHunkStatus {
3692                    kind: status_kind,
3693                    secondary: hunk.secondary_status,
3694                },
3695            })
3696        })
3697    }
3698
3699    fn excerpts_for_range<T: ToOffset>(
3700        &self,
3701        range: Range<T>,
3702    ) -> impl Iterator<Item = &Excerpt> + '_ {
3703        let range = range.start.to_offset(self)..range.end.to_offset(self);
3704        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3705        cursor.seek(&range.start);
3706        std::iter::from_fn(move || {
3707            let region = cursor.region()?;
3708            if region.range.start > range.end
3709                || region.range.start == range.end && region.range.start > range.start
3710            {
3711                return None;
3712            }
3713            let excerpt = region.excerpt;
3714            cursor.next_excerpt_forwards();
3715            Some(excerpt)
3716        })
3717    }
3718
3719    pub fn excerpt_ids_for_range<T: ToOffset>(
3720        &self,
3721        range: Range<T>,
3722    ) -> impl Iterator<Item = ExcerptId> + '_ {
3723        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3724    }
3725
3726    pub fn buffer_ids_for_range<T: ToOffset>(
3727        &self,
3728        range: Range<T>,
3729    ) -> impl Iterator<Item = BufferId> + '_ {
3730        self.excerpts_for_range(range)
3731            .map(|excerpt| excerpt.buffer_id)
3732    }
3733
3734    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3735    ///
3736    /// The passed in anchors must be ordered.
3737    pub fn text_anchors_to_visible_anchors(
3738        &self,
3739        anchors: impl IntoIterator<Item = text::Anchor>,
3740    ) -> Vec<Option<Anchor>> {
3741        let anchors = anchors.into_iter();
3742        let mut result = Vec::with_capacity(anchors.size_hint().0);
3743        let mut anchors = anchors.peekable();
3744        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3745        'anchors: while let Some(anchor) = anchors.peek() {
3746            let Some(buffer_id) = anchor.buffer_id else {
3747                anchors.next();
3748                result.push(None);
3749                continue 'anchors;
3750            };
3751            let mut same_buffer_anchors =
3752                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3753
3754            if let Some(path) = self.path_keys_by_buffer.get(&buffer_id) {
3755                let Some(mut next) = same_buffer_anchors.next() else {
3756                    continue 'anchors;
3757                };
3758                cursor.seek_forward(path, Bias::Left);
3759                'excerpts: loop {
3760                    let Some(excerpt) = cursor.item() else {
3761                        break;
3762                    };
3763                    if &excerpt.path_key != path {
3764                        break;
3765                    }
3766
3767                    loop {
3768                        // anchor is before the first excerpt
3769                        if excerpt
3770                            .range
3771                            .context
3772                            .start
3773                            .cmp(&next, &excerpt.buffer)
3774                            .is_gt()
3775                        {
3776                            // so we skip it and try the next anchor
3777                            result.push(None);
3778                            match same_buffer_anchors.next() {
3779                                Some(anchor) => next = anchor,
3780                                None => continue 'anchors,
3781                            }
3782                        // anchor is within the excerpt
3783                        } else if excerpt
3784                            .range
3785                            .context
3786                            .end
3787                            .cmp(&next, &excerpt.buffer)
3788                            .is_ge()
3789                        {
3790                            // record it and all following anchors that are within
3791                            result.push(Some(Anchor::text(excerpt.id, next)));
3792                            result.extend(
3793                                same_buffer_anchors
3794                                    .peeking_take_while(|a| {
3795                                        excerpt.range.context.end.cmp(a, &excerpt.buffer).is_ge()
3796                                    })
3797                                    .map(|a| Some(Anchor::text(excerpt.id, a))),
3798                            );
3799                            match same_buffer_anchors.next() {
3800                                Some(anchor) => next = anchor,
3801                                None => continue 'anchors,
3802                            }
3803                        // anchor is after the excerpt, try the next one
3804                        } else {
3805                            cursor.next();
3806                            continue 'excerpts;
3807                        }
3808                    }
3809                }
3810                // account for `next`
3811                result.push(None);
3812            }
3813            result.extend(same_buffer_anchors.map(|_| None));
3814        }
3815
3816        result
3817    }
3818
3819    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3820        &self,
3821        ranges: impl Iterator<Item = Range<T>>,
3822    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3823        ranges.flat_map(|range| {
3824            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3825                .into_iter()
3826        })
3827    }
3828
3829    pub fn range_to_buffer_ranges<R, T>(
3830        &self,
3831        range: R,
3832    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
3833    where
3834        R: RangeBounds<T>,
3835        T: ToOffset,
3836    {
3837        self.range_to_buffer_ranges_with_context(range)
3838            .into_iter()
3839            .map(|(buffer, range, id, _context)| (buffer, range, id))
3840            .collect()
3841    }
3842
3843    pub fn range_to_buffer_ranges_with_context<R, T>(
3844        &self,
3845        range: R,
3846    ) -> Vec<(
3847        &BufferSnapshot,
3848        Range<BufferOffset>,
3849        ExcerptId,
3850        Range<text::Anchor>,
3851    )>
3852    where
3853        R: RangeBounds<T>,
3854        T: ToOffset,
3855    {
3856        let start = match range.start_bound() {
3857            Bound::Included(start) => start.to_offset(self),
3858            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3859            Bound::Unbounded => MultiBufferOffset::ZERO,
3860        };
3861        let end_bound = match range.end_bound() {
3862            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3863            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3864            Bound::Unbounded => Bound::Unbounded,
3865        };
3866        let bounds = (Bound::Included(start), end_bound);
3867
3868        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3869        cursor.seek(&start);
3870
3871        let mut result: Vec<(
3872            &BufferSnapshot,
3873            Range<BufferOffset>,
3874            ExcerptId,
3875            Range<text::Anchor>,
3876        )> = Vec::new();
3877        while let Some(region) = cursor.region() {
3878            let dominated_by_end_bound = match end_bound {
3879                Bound::Included(end) => region.range.start > end,
3880                Bound::Excluded(end) => region.range.start >= end,
3881                Bound::Unbounded => false,
3882            };
3883            if dominated_by_end_bound {
3884                break;
3885            }
3886            if region.is_main_buffer {
3887                let start_overshoot = start.saturating_sub(region.range.start);
3888                let end_offset = match end_bound {
3889                    Bound::Included(end) | Bound::Excluded(end) => end,
3890                    Bound::Unbounded => region.range.end,
3891                };
3892                let end_overshoot = end_offset.saturating_sub(region.range.start);
3893                let start = region
3894                    .buffer_range
3895                    .end
3896                    .min(region.buffer_range.start + start_overshoot);
3897                let end = region
3898                    .buffer_range
3899                    .end
3900                    .min(region.buffer_range.start + end_overshoot);
3901                let context = region.excerpt.range.context.clone();
3902                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
3903                    *excerpt_id == region.excerpt.id && prev_range.end == start
3904                }) {
3905                    prev.1.end = end;
3906                } else {
3907                    result.push((region.buffer, start..end, region.excerpt.id, context));
3908                }
3909            }
3910            cursor.next();
3911        }
3912
3913        if let Some(excerpt) = cursor.excerpt() {
3914            let dominated_by_prev_excerpt =
3915                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
3916            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3917                let excerpt_position = self.len();
3918                if bounds.contains(&excerpt_position) {
3919                    let buffer_offset =
3920                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
3921                    let context = excerpt.range.context.clone();
3922                    result.push((
3923                        &excerpt.buffer,
3924                        buffer_offset..buffer_offset,
3925                        excerpt.id,
3926                        context,
3927                    ));
3928                }
3929            }
3930        }
3931
3932        result
3933    }
3934
3935    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3936        &self,
3937        range: Range<T>,
3938    ) -> impl Iterator<
3939        Item = (
3940            &BufferSnapshot,
3941            Range<BufferOffset>,
3942            ExcerptId,
3943            Option<Anchor>,
3944        ),
3945    > + '_ {
3946        let start = range.start.to_offset(self);
3947        let end = range.end.to_offset(self);
3948
3949        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3950        cursor.seek(&start);
3951
3952        std::iter::from_fn(move || {
3953            let region = cursor.region()?;
3954            if region.range.start > end {
3955                return None;
3956            }
3957            let start_overshoot = start.saturating_sub(region.range.start);
3958            let end_overshoot = end.saturating_sub(region.range.start);
3959            let start = region
3960                .buffer_range
3961                .end
3962                .min(region.buffer_range.start + start_overshoot);
3963            let end = region
3964                .buffer_range
3965                .end
3966                .min(region.buffer_range.start + end_overshoot);
3967
3968            let region_excerpt_id = region.excerpt.id;
3969            let deleted_hunk_anchor = if region.is_main_buffer {
3970                None
3971            } else {
3972                Some(self.anchor_before(region.range.start))
3973            };
3974            let result = (
3975                region.buffer,
3976                start..end,
3977                region_excerpt_id,
3978                deleted_hunk_anchor,
3979            );
3980            cursor.next();
3981            Some(result)
3982        })
3983    }
3984
3985    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3986    /// coordinates.
3987    ///
3988    /// The given callback will be called for every excerpt intersecting the given range. It will
3989    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3990    /// The callback should return an iterator of metadata items from that buffer, each paired
3991    /// with a buffer range.
3992    ///
3993    /// The returned iterator yields each of these metadata items, paired with its range in
3994    /// multi-buffer coordinates.
3995    fn lift_buffer_metadata<'a, MBD, M, I>(
3996        &'a self,
3997        query_range: Range<MBD>,
3998        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3999    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4000    where
4001        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4002        MBD: MultiBufferDimension
4003            + Ord
4004            + Sub<Output = MBD::TextDimension>
4005            + ops::Add<MBD::TextDimension, Output = MBD>
4006            + ops::AddAssign<MBD::TextDimension>,
4007        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4008            + ops::Add<Output = MBD::TextDimension>
4009            + AddAssign<MBD::TextDimension>
4010            + Ord,
4011    {
4012        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4013        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4014
4015        // Find the excerpt and buffer offset where the given range ends.
4016        cursor.seek(&query_range.end);
4017        let mut range_end = None;
4018        while let Some(region) = cursor.region() {
4019            if region.is_main_buffer {
4020                let mut buffer_end = region.buffer_range.start;
4021                let overshoot = if query_range.end > region.range.start {
4022                    query_range.end - region.range.start
4023                } else {
4024                    <MBD::TextDimension>::default()
4025                };
4026                buffer_end = buffer_end + overshoot;
4027                range_end = Some((region.excerpt.id, buffer_end));
4028                break;
4029            }
4030            cursor.next();
4031        }
4032
4033        cursor.seek(&query_range.start);
4034
4035        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4036            && region.range.start > MBD::default()
4037        {
4038            cursor.prev()
4039        } else if let Some(region) = cursor.region()
4040            && region.is_main_buffer
4041            && region.diff_hunk_status.is_some()
4042        {
4043            cursor.prev();
4044            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4045                cursor.next();
4046            }
4047        }
4048
4049        iter::from_fn(move || {
4050            loop {
4051                let excerpt = cursor.excerpt()?;
4052
4053                // If we have already retrieved metadata for this excerpt, continue to use it.
4054                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4055                    .as_mut()
4056                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4057                {
4058                    Some(metadata)
4059                }
4060                // Otherwise, compute the intersection of the input range with the excerpt's range,
4061                // and retrieve the metadata for the resulting range.
4062                else {
4063                    let region = cursor.region()?;
4064                    let mut buffer_start;
4065                    if region.is_main_buffer {
4066                        buffer_start = region.buffer_range.start;
4067                        if query_range.start > region.range.start {
4068                            let overshoot = query_range.start - region.range.start;
4069                            buffer_start = buffer_start + overshoot;
4070                        }
4071                        buffer_start = buffer_start.min(region.buffer_range.end);
4072                    } else {
4073                        buffer_start = cursor.main_buffer_position()?;
4074                    };
4075                    let mut buffer_end = excerpt
4076                        .range
4077                        .context
4078                        .end
4079                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4080                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4081                        && excerpt.id == end_excerpt_id
4082                    {
4083                        buffer_end = buffer_end.min(end_buffer_offset);
4084                    }
4085
4086                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4087                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4088                    })
4089                };
4090
4091                // Visit each metadata item.
4092                if let Some((metadata_buffer_range, metadata)) =
4093                    metadata_iter.and_then(Iterator::next)
4094                {
4095                    // Find the multibuffer regions that contain the start and end of
4096                    // the metadata item's range.
4097                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4098                        while let Some(region) = cursor.region() {
4099                            if (region.is_main_buffer
4100                                && (region.buffer_range.end >= metadata_buffer_range.start
4101                                    || cursor.is_at_end_of_excerpt()))
4102                                || (!region.is_main_buffer
4103                                    && region.buffer_range.start == metadata_buffer_range.start)
4104                            {
4105                                break;
4106                            }
4107                            cursor.next();
4108                        }
4109                    }
4110                    let start_region = cursor.region()?.clone();
4111                    while let Some(region) = cursor.region() {
4112                        if region.is_main_buffer
4113                            && (region.buffer_range.end > metadata_buffer_range.end
4114                                || cursor.is_at_end_of_excerpt())
4115                        {
4116                            break;
4117                        }
4118                        cursor.next();
4119                    }
4120                    let end_region = cursor.region();
4121
4122                    // Convert the metadata item's range into multibuffer coordinates.
4123                    let mut start_position = start_region.range.start;
4124                    let region_buffer_start = start_region.buffer_range.start;
4125                    if start_region.is_main_buffer
4126                        && metadata_buffer_range.start > region_buffer_start
4127                    {
4128                        start_position =
4129                            start_position + (metadata_buffer_range.start - region_buffer_start);
4130                        start_position = start_position.min(start_region.range.end);
4131                    }
4132
4133                    let mut end_position = self.max_position();
4134                    if let Some(end_region) = &end_region {
4135                        end_position = end_region.range.start;
4136                        debug_assert!(end_region.is_main_buffer);
4137                        let region_buffer_start = end_region.buffer_range.start;
4138                        if metadata_buffer_range.end > region_buffer_start {
4139                            end_position =
4140                                end_position + (metadata_buffer_range.end - region_buffer_start);
4141                        }
4142                        end_position = end_position.min(end_region.range.end);
4143                    }
4144
4145                    if start_position <= query_range.end && end_position >= query_range.start {
4146                        return Some((start_position..end_position, metadata, excerpt));
4147                    }
4148                }
4149                // When there are no more metadata items for this excerpt, move to the next excerpt.
4150                else {
4151                    current_excerpt_metadata.take();
4152                    if let Some((end_excerpt_id, _)) = range_end
4153                        && excerpt.id == end_excerpt_id
4154                    {
4155                        return None;
4156                    }
4157                    cursor.next_excerpt_forwards();
4158                }
4159            }
4160        })
4161    }
4162
4163    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4164        let offset = position.to_offset(self);
4165
4166        let mut cursor = self
4167            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4168            );
4169        cursor.seek(&DimensionPair {
4170            key: offset,
4171            value: None,
4172        });
4173        cursor.seek_to_start_of_current_excerpt();
4174        let excerpt = cursor.excerpt()?;
4175
4176        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4177        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4178        let current_position = self
4179            .anchor_before(offset)
4180            .text_anchor
4181            .to_offset(&excerpt.buffer);
4182
4183        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4184            if let Some(main_buffer) = &diff.main_buffer {
4185                for hunk in diff
4186                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4187                {
4188                    if hunk.diff_base_byte_range.end >= current_position {
4189                        continue;
4190                    }
4191                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4192                    let start = Anchor::text(excerpt.id, hunk_start).to_point(self);
4193                    return Some(MultiBufferRow(start.row));
4194                }
4195            } else {
4196                let excerpt_end = excerpt
4197                    .buffer
4198                    .anchor_before(excerpt_end.min(current_position));
4199                for hunk in diff.hunks_intersecting_range_rev(
4200                    excerpt.range.context.start..excerpt_end,
4201                    &excerpt.buffer,
4202                ) {
4203                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4204                    if hunk_end >= current_position {
4205                        continue;
4206                    }
4207                    let start = Anchor::text(excerpt.id, hunk.buffer_range.start).to_point(self);
4208                    return Some(MultiBufferRow(start.row));
4209                }
4210            }
4211        }
4212
4213        loop {
4214            cursor.prev_excerpt();
4215            let excerpt = cursor.excerpt()?;
4216
4217            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4218                continue;
4219            };
4220            if let Some(main_buffer) = &diff.main_buffer {
4221                let Some(hunk) = diff
4222                    .hunks_intersecting_base_text_range_rev(
4223                        excerpt.range.context.to_offset(&excerpt.buffer),
4224                        main_buffer,
4225                    )
4226                    .next()
4227                else {
4228                    continue;
4229                };
4230                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4231                let start = Anchor::text(excerpt.id, hunk_start).to_point(self);
4232                return Some(MultiBufferRow(start.row));
4233            } else {
4234                let Some(hunk) = diff
4235                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4236                    .next()
4237                else {
4238                    continue;
4239                };
4240                let start = Anchor::text(excerpt.id, hunk.buffer_range.start).to_point(self);
4241                return Some(MultiBufferRow(start.row));
4242            }
4243        }
4244    }
4245
4246    pub fn has_diff_hunks(&self) -> bool {
4247        self.diffs.values().any(|diff| !diff.is_empty())
4248    }
4249
4250    pub fn is_inside_word<T: ToOffset>(
4251        &self,
4252        position: T,
4253        scope_context: Option<CharScopeContext>,
4254    ) -> bool {
4255        let position = position.to_offset(self);
4256        let classifier = self
4257            .char_classifier_at(position)
4258            .scope_context(scope_context);
4259        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4260        let prev_char_kind = self
4261            .reversed_chars_at(position)
4262            .next()
4263            .map(|c| classifier.kind(c));
4264        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4265    }
4266
4267    pub fn surrounding_word<T: ToOffset>(
4268        &self,
4269        start: T,
4270        scope_context: Option<CharScopeContext>,
4271    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4272        let mut start = start.to_offset(self);
4273        let mut end = start;
4274        let mut next_chars = self.chars_at(start).peekable();
4275        let mut prev_chars = self.reversed_chars_at(start).peekable();
4276
4277        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4278
4279        let word_kind = cmp::max(
4280            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4281            next_chars.peek().copied().map(|c| classifier.kind(c)),
4282        );
4283
4284        for ch in prev_chars {
4285            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4286                start -= ch.len_utf8();
4287            } else {
4288                break;
4289            }
4290        }
4291
4292        for ch in next_chars {
4293            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4294                end += ch.len_utf8();
4295            } else {
4296                break;
4297            }
4298        }
4299
4300        (start..end, word_kind)
4301    }
4302
4303    pub fn char_kind_before<T: ToOffset>(
4304        &self,
4305        start: T,
4306        scope_context: Option<CharScopeContext>,
4307    ) -> Option<CharKind> {
4308        let start = start.to_offset(self);
4309        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4310        self.reversed_chars_at(start)
4311            .next()
4312            .map(|ch| classifier.kind(ch))
4313    }
4314
4315    pub fn is_singleton(&self) -> bool {
4316        self.singleton
4317    }
4318
4319    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4320        if self.singleton {
4321            self.excerpts
4322                .iter()
4323                .next()
4324                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4325        } else {
4326            None
4327        }
4328    }
4329
4330    pub fn len(&self) -> MultiBufferOffset {
4331        self.diff_transforms.summary().output.len
4332    }
4333
4334    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4335        MBD::from_summary(&self.text_summary())
4336    }
4337
4338    pub fn is_empty(&self) -> bool {
4339        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4340    }
4341
4342    pub fn widest_line_number(&self) -> u32 {
4343        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4344        self.excerpts.summary().widest_line_number + 1
4345    }
4346
4347    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4348        let range = range.start.to_offset(self)..range.end.to_offset(self);
4349        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4350        excerpts.seek(&range.start);
4351
4352        let mut chunk;
4353        let mut has_trailing_newline;
4354        let excerpt_bytes;
4355        if let Some(region) = excerpts.region() {
4356            let mut bytes = region.buffer.bytes_in_range(
4357                region.buffer_range.start + (range.start - region.range.start)
4358                    ..(region.buffer_range.start + (range.end - region.range.start))
4359                        .min(region.buffer_range.end),
4360            );
4361            chunk = bytes.next().unwrap_or(&[][..]);
4362            excerpt_bytes = Some(bytes);
4363            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4364            if chunk.is_empty() && has_trailing_newline {
4365                chunk = b"\n";
4366                has_trailing_newline = false;
4367            }
4368        } else {
4369            chunk = &[][..];
4370            excerpt_bytes = None;
4371            has_trailing_newline = false;
4372        };
4373
4374        MultiBufferBytes {
4375            range,
4376            cursor: excerpts,
4377            excerpt_bytes,
4378            has_trailing_newline,
4379            chunk,
4380        }
4381    }
4382
4383    pub fn reversed_bytes_in_range<T: ToOffset>(
4384        &self,
4385        range: Range<T>,
4386    ) -> ReversedMultiBufferBytes<'_> {
4387        let range = range.start.to_offset(self)..range.end.to_offset(self);
4388        let mut chunks = self.reversed_chunks_in_range(range.clone());
4389        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4390        ReversedMultiBufferBytes {
4391            range,
4392            chunks,
4393            chunk,
4394        }
4395    }
4396
4397    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4398        let mut cursor = self.cursor::<Point, Point>();
4399        cursor.seek(&Point::new(start_row.0, 0));
4400        let mut result = MultiBufferRows {
4401            point: Point::new(0, 0),
4402            is_empty: self.excerpts.is_empty(),
4403            is_singleton: self.is_singleton(),
4404            cursor,
4405        };
4406        result.seek(start_row);
4407        result
4408    }
4409
4410    pub fn chunks<T: ToOffset>(
4411        &self,
4412        range: Range<T>,
4413        language_aware: bool,
4414    ) -> MultiBufferChunks<'_> {
4415        let mut chunks = MultiBufferChunks {
4416            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4417                ..ExcerptDimension(MultiBufferOffset::ZERO),
4418            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4419            excerpts: self.excerpts.cursor(()),
4420            diff_transforms: self.diff_transforms.cursor(()),
4421            diffs: &self.diffs,
4422            diff_base_chunks: None,
4423            excerpt_chunks: None,
4424            buffer_chunk: None,
4425            language_aware,
4426        };
4427        let range = range.start.to_offset(self)..range.end.to_offset(self);
4428        chunks.seek(range);
4429        chunks
4430    }
4431
4432    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4433        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4434    }
4435
4436    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4437        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4438    }
4439
4440    pub fn clip_offset_utf16(
4441        &self,
4442        offset: MultiBufferOffsetUtf16,
4443        bias: Bias,
4444    ) -> MultiBufferOffsetUtf16 {
4445        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4446    }
4447
4448    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4449        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4450            buffer.clip_point_utf16(Unclipped(point), bias)
4451        })
4452    }
4453
4454    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4455        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4456    }
4457
4458    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4459        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4460    }
4461
4462    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4463        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4464    }
4465
4466    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4467        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4468    }
4469
4470    #[instrument(skip_all)]
4471    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4472        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4473    }
4474
4475    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4476        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4477    }
4478
4479    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4480        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4481    }
4482
4483    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4484        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4485    }
4486
4487    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4488        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4489    }
4490
4491    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4492        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4493    }
4494
4495    fn clip_dimension<MBD, BD>(
4496        &self,
4497        position: MBD,
4498        bias: Bias,
4499        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4500    ) -> MBD
4501    where
4502        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4503        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4504    {
4505        let mut cursor = self.cursor::<MBD, BD>();
4506        cursor.seek(&position);
4507        if let Some(region) = cursor.region() {
4508            if position >= region.range.end {
4509                return region.range.end;
4510            }
4511            let overshoot = position - region.range.start;
4512            let mut buffer_position = region.buffer_range.start;
4513            buffer_position += overshoot;
4514            let clipped_buffer_position =
4515                clip_buffer_position(region.buffer, buffer_position, bias);
4516            let mut position = region.range.start;
4517            position += clipped_buffer_position - region.buffer_range.start;
4518            position
4519        } else {
4520            self.max_position()
4521        }
4522    }
4523
4524    #[instrument(skip_all)]
4525    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4526        &self,
4527        key: MBR1,
4528        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4529    ) -> MBR2
4530    where
4531        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4532        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4533        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4534        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4535    {
4536        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4537        cursor.seek(&DimensionPair { key, value: None });
4538        if let Some(region) = cursor.region() {
4539            if key >= region.range.end.key {
4540                return region.range.end.value.unwrap();
4541            }
4542            let start_key = region.range.start.key;
4543            let start_value = region.range.start.value.unwrap();
4544            let buffer_start_key = region.buffer_range.start.key;
4545            let buffer_start_value = region.buffer_range.start.value.unwrap();
4546            let mut buffer_key = buffer_start_key;
4547            buffer_key += key - start_key;
4548            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4549            let mut result = start_value;
4550            result += buffer_value - buffer_start_value;
4551            result
4552        } else {
4553            self.max_position()
4554        }
4555    }
4556
4557    pub fn point_to_buffer_offset<T: ToOffset>(
4558        &self,
4559        point: T,
4560    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4561        let offset = point.to_offset(self);
4562        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4563        cursor.seek(&offset);
4564        let region = cursor.region()?;
4565        let overshoot = offset - region.range.start;
4566        let buffer_offset = region.buffer_range.start + overshoot;
4567        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4568            && region.has_trailing_newline
4569            && !region.is_main_buffer
4570        {
4571            let main_buffer_position = cursor.main_buffer_position()?;
4572            let buffer_snapshot = &cursor.excerpt()?.buffer;
4573            return Some((buffer_snapshot, main_buffer_position));
4574        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4575            return None;
4576        }
4577        Some((region.buffer, buffer_offset))
4578    }
4579
4580    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4581        let mut cursor = self.cursor::<Point, Point>();
4582        cursor.seek(&point);
4583        let region = cursor.region()?;
4584        let overshoot = point - region.range.start;
4585        let buffer_point = region.buffer_range.start + overshoot;
4586        let excerpt = cursor.excerpt()?;
4587        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4588            && region.has_trailing_newline
4589            && !region.is_main_buffer
4590        {
4591            return Some((&excerpt.buffer, cursor.main_buffer_position()?));
4592        } else if buffer_point > region.buffer.max_point() {
4593            return None;
4594        }
4595        Some((region.buffer, buffer_point))
4596    }
4597
4598    pub fn suggested_indents(
4599        &self,
4600        rows: impl IntoIterator<Item = u32>,
4601        cx: &App,
4602    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4603        let mut result = BTreeMap::new();
4604        self.suggested_indents_callback(
4605            rows,
4606            &mut |row, indent| {
4607                result.insert(row, indent);
4608                ControlFlow::Continue(())
4609            },
4610            cx,
4611        );
4612        result
4613    }
4614
4615    // move this to be a generator once those are a thing
4616    pub fn suggested_indents_callback(
4617        &self,
4618        rows: impl IntoIterator<Item = u32>,
4619        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4620        cx: &App,
4621    ) {
4622        let mut rows_for_excerpt = Vec::new();
4623        let mut cursor = self.cursor::<Point, Point>();
4624        let mut rows = rows.into_iter().peekable();
4625        let mut prev_row = u32::MAX;
4626        let mut prev_language_indent_size = IndentSize::default();
4627
4628        while let Some(row) = rows.next() {
4629            cursor.seek(&Point::new(row, 0));
4630            let Some(region) = cursor.region() else {
4631                continue;
4632            };
4633
4634            // Retrieve the language and indent size once for each disjoint region being indented.
4635            let single_indent_size = if row.saturating_sub(1) == prev_row {
4636                prev_language_indent_size
4637            } else {
4638                region
4639                    .buffer
4640                    .language_indent_size_at(Point::new(row, 0), cx)
4641            };
4642            prev_language_indent_size = single_indent_size;
4643            prev_row = row;
4644
4645            let start_buffer_row = region.buffer_range.start.row;
4646            let start_multibuffer_row = region.range.start.row;
4647            let end_multibuffer_row = region.range.end.row;
4648
4649            rows_for_excerpt.push(row);
4650            while let Some(next_row) = rows.peek().copied() {
4651                if end_multibuffer_row > next_row {
4652                    rows_for_excerpt.push(next_row);
4653                    rows.next();
4654                } else {
4655                    break;
4656                }
4657            }
4658
4659            let buffer_rows = rows_for_excerpt
4660                .drain(..)
4661                .map(|row| start_buffer_row + row - start_multibuffer_row);
4662            let buffer_indents = region
4663                .buffer
4664                .suggested_indents(buffer_rows, single_indent_size);
4665            for (row, indent) in buffer_indents {
4666                if cb(
4667                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4668                    indent,
4669                )
4670                .is_break()
4671                {
4672                    return;
4673                }
4674            }
4675        }
4676    }
4677
4678    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4679        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4680            let mut size = buffer.indent_size_for_line(range.start.row);
4681            size.len = size
4682                .len
4683                .min(range.end.column)
4684                .saturating_sub(range.start.column);
4685            size
4686        } else {
4687            IndentSize::spaces(0)
4688        }
4689    }
4690
4691    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4692        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4693            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4694        } else {
4695            LineIndent::spaces(0)
4696        }
4697    }
4698
4699    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4700        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4701
4702        if self.language_settings(cx).extend_comment_on_newline
4703            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4704        {
4705            let delimiters = language_scope.line_comment_prefixes();
4706            for delimiter in delimiters {
4707                if *self
4708                    .chars_at(Point::new(row.0, indent.len() as u32))
4709                    .take(delimiter.chars().count())
4710                    .collect::<String>()
4711                    .as_str()
4712                    == **delimiter
4713                {
4714                    indent.push_str(delimiter);
4715                    break;
4716                }
4717            }
4718        }
4719
4720        indent
4721    }
4722
4723    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4724    where
4725        T: ToOffset,
4726    {
4727        for char in self.reversed_chars_at(position) {
4728            if !char.is_whitespace() {
4729                return false;
4730            }
4731            if char == '\n' {
4732                return true;
4733            }
4734        }
4735        true
4736    }
4737
4738    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4739        while row.0 > 0 {
4740            row.0 -= 1;
4741            if !self.is_line_blank(row) {
4742                return Some(row);
4743            }
4744        }
4745        None
4746    }
4747
4748    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4749        if let Some((_, range)) = self.buffer_line_for_row(row) {
4750            range.end.column - range.start.column
4751        } else {
4752            0
4753        }
4754    }
4755
4756    pub fn buffer_line_for_row(
4757        &self,
4758        row: MultiBufferRow,
4759    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4760        let mut cursor = self.cursor::<Point, Point>();
4761        let point = Point::new(row.0, 0);
4762        cursor.seek(&point);
4763        let region = cursor.region()?;
4764        let overshoot = point.min(region.range.end) - region.range.start;
4765        let buffer_point = region.buffer_range.start + overshoot;
4766        if buffer_point.row > region.buffer_range.end.row {
4767            return None;
4768        }
4769        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4770        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4771            .min(region.buffer_range.end);
4772        Some((region.buffer, line_start..line_end))
4773    }
4774
4775    pub fn max_point(&self) -> Point {
4776        self.text_summary().lines
4777    }
4778
4779    pub fn max_row(&self) -> MultiBufferRow {
4780        MultiBufferRow(self.text_summary().lines.row)
4781    }
4782
4783    pub fn text_summary(&self) -> MBTextSummary {
4784        self.diff_transforms.summary().output
4785    }
4786
4787    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4788    where
4789        MBD: MultiBufferDimension + AddAssign,
4790        O: ToOffset,
4791    {
4792        let range = range.start.to_offset(self)..range.end.to_offset(self);
4793        let mut cursor = self
4794            .diff_transforms
4795            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4796        cursor.seek(&range.start, Bias::Right);
4797
4798        let Some(first_transform) = cursor.item() else {
4799            return MBD::from_summary(&MBTextSummary::default());
4800        };
4801
4802        let diff_transform_start = cursor.start().0;
4803        let diff_transform_end = cursor.end().0;
4804        let diff_start = range.start;
4805        let start_overshoot = diff_start - diff_transform_start;
4806        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4807
4808        let mut result = match first_transform {
4809            DiffTransform::BufferContent { .. } => {
4810                let excerpt_start = cursor.start().1 + start_overshoot;
4811                let excerpt_end = cursor.start().1 + end_overshoot;
4812                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4813            }
4814            DiffTransform::DeletedHunk {
4815                buffer_id,
4816                base_text_byte_range,
4817                has_trailing_newline,
4818                ..
4819            } => {
4820                let buffer_start = base_text_byte_range.start + start_overshoot;
4821                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4822                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4823                    panic!("{:?} is in non-existent deleted hunk", range.start)
4824                };
4825
4826                let include_trailing_newline =
4827                    *has_trailing_newline && range.end >= diff_transform_end;
4828                if include_trailing_newline {
4829                    buffer_end -= 1;
4830                }
4831
4832                let mut summary = base_text
4833                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4834
4835                if include_trailing_newline {
4836                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4837                        &TextSummary::newline(),
4838                    ))
4839                }
4840
4841                let mut result = MBD::default();
4842                result.add_text_dim(&summary);
4843                result
4844            }
4845        };
4846        if range.end < diff_transform_end {
4847            return result;
4848        }
4849
4850        cursor.next();
4851        result.add_mb_text_summary(
4852            &cursor
4853                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4854                .0,
4855        );
4856
4857        let Some(last_transform) = cursor.item() else {
4858            return result;
4859        };
4860
4861        let overshoot = range.end - cursor.start().0;
4862        let suffix = match last_transform {
4863            DiffTransform::BufferContent { .. } => {
4864                let end = cursor.start().1 + overshoot;
4865                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4866            }
4867            DiffTransform::DeletedHunk {
4868                base_text_byte_range,
4869                buffer_id,
4870                has_trailing_newline,
4871                ..
4872            } => {
4873                let buffer_end = base_text_byte_range.start + overshoot;
4874                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4875                    panic!("{:?} is in non-existent deleted hunk", range.end)
4876                };
4877
4878                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4879                    base_text_byte_range.start..buffer_end,
4880                );
4881                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4882                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4883                        &TextSummary::from("\n"),
4884                    ))
4885                }
4886
4887                let mut result = MBD::default();
4888                result.add_text_dim(&suffix);
4889                result
4890            }
4891        };
4892
4893        result += suffix;
4894        result
4895    }
4896
4897    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4898    where
4899        MBD: MultiBufferDimension + AddAssign,
4900    {
4901        let mut summary = MBD::default();
4902        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4903        cursor.seek(&range.start, Bias::Right);
4904        if let Some(excerpt) = cursor.item() {
4905            let mut end_before_newline = cursor.end();
4906            if excerpt.has_trailing_newline {
4907                end_before_newline -= 1;
4908            }
4909
4910            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4911            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4912            let end_in_excerpt =
4913                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4914            summary.add_text_dim(
4915                &excerpt
4916                    .buffer
4917                    .text_summary_for_range::<MBD::TextDimension, _>(
4918                        start_in_excerpt..end_in_excerpt,
4919                    ),
4920            );
4921
4922            if range.end > end_before_newline {
4923                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4924            }
4925
4926            cursor.next();
4927        }
4928
4929        if range.end > *cursor.start() {
4930            summary += cursor
4931                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4932                .0;
4933            if let Some(excerpt) = cursor.item() {
4934                range.end = cmp::max(*cursor.start(), range.end);
4935
4936                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4937                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4938                summary.add_text_dim(
4939                    &excerpt
4940                        .buffer
4941                        .text_summary_for_range::<MBD::TextDimension, _>(
4942                            excerpt_start..end_in_excerpt,
4943                        ),
4944                );
4945            }
4946        }
4947
4948        summary
4949    }
4950
4951    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4952    where
4953        MBD: MultiBufferDimension
4954            + Ord
4955            + Sub<Output = MBD::TextDimension>
4956            + Sub<MBD::TextDimension, Output = MBD>
4957            + AddAssign<MBD::TextDimension>
4958            + Add<MBD::TextDimension, Output = MBD>,
4959        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4960    {
4961        let target = anchor.seek_target(self);
4962        let anchor = match anchor {
4963            Anchor::Min => {
4964                return MBD::default();
4965            }
4966            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4967            Anchor::Max => {
4968                return MBD::from_summary(&self.text_summary());
4969            }
4970        };
4971
4972        let (start, _, item) = self
4973            .excerpts
4974            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4975        let start = MBD::from_summary(&start.text);
4976
4977        let excerpt_start_position = ExcerptDimension(start);
4978        if self.diff_transforms.is_empty() {
4979            if let Some(excerpt) = item {
4980                if !excerpt.contains(anchor) {
4981                    return excerpt_start_position.0;
4982                }
4983                let excerpt_buffer_start = excerpt
4984                    .range
4985                    .context
4986                    .start
4987                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4988                let excerpt_buffer_end = excerpt
4989                    .range
4990                    .context
4991                    .end
4992                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4993                let buffer_summary = anchor
4994                    .text_anchor()
4995                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4996                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4997                let mut position = excerpt_start_position;
4998                if summary > excerpt_buffer_start {
4999                    position += summary - excerpt_buffer_start;
5000                }
5001
5002                position.0
5003            } else {
5004                excerpt_start_position.0
5005            }
5006        } else {
5007            let mut diff_transforms_cursor = self
5008                .diff_transforms
5009                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5010            diff_transforms_cursor.next();
5011
5012            if let Some(excerpt) = item {
5013                if !excerpt.contains(anchor) {
5014                    return self.summary_for_excerpt_position_without_hunks(
5015                        Bias::Left,
5016                        excerpt_start_position,
5017                        &mut diff_transforms_cursor,
5018                    );
5019                }
5020                let excerpt_buffer_start = excerpt
5021                    .range
5022                    .context
5023                    .start
5024                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5025                let excerpt_buffer_end = excerpt
5026                    .range
5027                    .context
5028                    .end
5029                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5030                let buffer_summary = anchor
5031                    .text_anchor()
5032                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5033                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5034                let mut position = excerpt_start_position;
5035                if summary > excerpt_buffer_start {
5036                    position += summary - excerpt_buffer_start;
5037                }
5038
5039                if diff_transforms_cursor.start().0 < position {
5040                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5041                }
5042                self.summary_for_anchor_with_excerpt_position(
5043                    *anchor,
5044                    position,
5045                    &mut diff_transforms_cursor,
5046                    &excerpt.buffer,
5047                )
5048            } else {
5049                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5050                self.summary_for_excerpt_position_without_hunks(
5051                    Bias::Right,
5052                    excerpt_start_position,
5053                    &mut diff_transforms_cursor,
5054                )
5055            }
5056        }
5057    }
5058
5059    /// Maps an anchor's excerpt-space position to its output-space position by
5060    /// walking the diff transforms. The cursor is shared across consecutive
5061    /// calls, so it may already be partway through the transform list.
5062    fn summary_for_anchor_with_excerpt_position<MBD>(
5063        &self,
5064        anchor: ExcerptAnchor,
5065        excerpt_position: ExcerptDimension<MBD>,
5066        diff_transforms: &mut Cursor<
5067            DiffTransform,
5068            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5069        >,
5070        excerpt_buffer: &text::BufferSnapshot,
5071    ) -> MBD
5072    where
5073        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5074    {
5075        loop {
5076            let transform_end_position = diff_transforms.end().0;
5077            let item = diff_transforms.item();
5078            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5079
5080            // A right-biased anchor at a transform boundary belongs to the
5081            // *next* transform, so advance past the current one.
5082            if anchor.bias == Bias::Right && at_transform_end {
5083                diff_transforms.next();
5084                continue;
5085            }
5086
5087            let mut position = diff_transforms.start().1;
5088            match item {
5089                Some(DiffTransform::DeletedHunk {
5090                    buffer_id,
5091                    base_text_byte_range,
5092                    hunk_info,
5093                    ..
5094                }) => {
5095                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
5096                        && let Some(base_text) =
5097                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5098                        && diff_base_anchor.is_valid(&base_text)
5099                    {
5100                        // The anchor carries a diff-base position — resolve it
5101                        // to a location inside the deleted hunk.
5102                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5103                        if base_text_offset >= base_text_byte_range.start
5104                            && base_text_offset <= base_text_byte_range.end
5105                        {
5106                            let position_in_hunk = base_text
5107                                .text_summary_for_range::<MBD::TextDimension, _>(
5108                                    base_text_byte_range.start..base_text_offset,
5109                                );
5110                            position.0.add_text_dim(&position_in_hunk);
5111                        } else if at_transform_end {
5112                            // diff_base offset falls outside this hunk's range;
5113                            // advance to see if the next transform is a better fit.
5114                            diff_transforms.next();
5115                            continue;
5116                        }
5117                    } else if at_transform_end
5118                        && anchor
5119                            .text_anchor()
5120                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5121                            .is_gt()
5122                    {
5123                        // The anchor has no (valid) diff-base position, so it
5124                        // belongs in the buffer content, not in the deleted
5125                        // hunk. However, after an edit deletes the text between
5126                        // the hunk boundary and this anchor, both resolve to
5127                        // the same excerpt_position—landing us here on the
5128                        // DeletedHunk left behind by the shared cursor. Use the
5129                        // CRDT ordering to detect that the anchor is strictly
5130                        // *past* the hunk boundary and skip to the following
5131                        // BufferContent.
5132                        diff_transforms.next();
5133                        continue;
5134                    }
5135                }
5136                _ => {
5137                    // On a BufferContent (or no transform). If the anchor
5138                    // carries a diff_base_anchor it needs a DeletedHunk, so
5139                    // advance to find one.
5140                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5141                        diff_transforms.next();
5142                        continue;
5143                    }
5144                    let overshoot = excerpt_position - diff_transforms.start().0;
5145                    position += overshoot;
5146                }
5147            }
5148
5149            return position.0;
5150        }
5151    }
5152
5153    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5154    fn summary_for_excerpt_position_without_hunks<MBD>(
5155        &self,
5156        bias: Bias,
5157        excerpt_position: ExcerptDimension<MBD>,
5158        diff_transforms: &mut Cursor<
5159            DiffTransform,
5160            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5161        >,
5162    ) -> MBD
5163    where
5164        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5165    {
5166        loop {
5167            let transform_end_position = diff_transforms.end().0;
5168            let item = diff_transforms.item();
5169            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5170
5171            // A right-biased anchor at a transform boundary belongs to the
5172            // *next* transform, so advance past the current one.
5173            if bias == Bias::Right && at_transform_end {
5174                diff_transforms.next();
5175                continue;
5176            }
5177
5178            let mut position = diff_transforms.start().1;
5179            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5180                let overshoot = excerpt_position - diff_transforms.start().0;
5181                position += overshoot;
5182            }
5183
5184            return position.0;
5185        }
5186    }
5187
5188    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5189        let anchor = match anchor {
5190            Anchor::Min => return ExcerptOffset::default(),
5191            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5192            Anchor::Max => return self.excerpts.summary().len(),
5193        };
5194        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5195        let target = self.anchor_seek_target(anchor);
5196
5197        cursor.seek(&target, Bias::Left);
5198        if cursor.item().is_none() && anchor.is_max() {
5199            cursor.prev();
5200        }
5201
5202        let mut position = cursor.start().len();
5203        if let Some(excerpt) = cursor.item()
5204            && (excerpt.contains(anchor) || anchor.is_max())
5205        {
5206            let excerpt_buffer_start = excerpt
5207                .buffer
5208                .offset_for_anchor(&excerpt.range.context.start);
5209            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5210            let buffer_position = cmp::min(
5211                excerpt_buffer_end,
5212                excerpt.buffer.offset_for_anchor(&text_anchor),
5213            );
5214            if buffer_position > excerpt_buffer_start {
5215                position += buffer_position - excerpt_buffer_start;
5216            }
5217        }
5218        position
5219    }
5220
5221    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5222        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5223            excerpt_id = *replacement;
5224        }
5225        excerpt_id
5226    }
5227
5228    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5229    where
5230        MBD: MultiBufferDimension
5231            + Ord
5232            + Sub<Output = MBD::TextDimension>
5233            + AddAssign<MBD::TextDimension>,
5234        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5235        I: 'a + IntoIterator<Item = &'a Anchor>,
5236    {
5237        let mut anchors = anchors.into_iter().peekable();
5238        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5239        let mut diff_transforms_cursor = self
5240            .diff_transforms
5241            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5242        diff_transforms_cursor.next();
5243
5244        let mut summaries = Vec::new();
5245        while let Some(anchor) = anchors.peek() {
5246            let target = anchor.seek_target(self);
5247            let excerpt_anchor = match anchor {
5248                Anchor::Min => {
5249                    summaries.push(MBD::default());
5250                    anchors.next();
5251                    continue;
5252                }
5253                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5254                Anchor::Max => {
5255                    summaries.push(self.excerpts.summary());
5256                    anchors.next();
5257                    continue;
5258                }
5259            };
5260
5261            cursor.seek_forward(&target, Bias::Left);
5262
5263            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5264            if let Some(excerpt) = cursor.item() {
5265                if !excerpt.contains(&excerpt_anchor) {
5266                    let position = self.summary_for_excerpt_position_without_hunks(
5267                        Bias::Left,
5268                        excerpt_start_position,
5269                        &mut diff_transforms_cursor,
5270                    );
5271                    summaries.push(position);
5272                    anchors.next();
5273                    continue;
5274                }
5275                let excerpt_buffer_start = excerpt
5276                    .range
5277                    .context
5278                    .start
5279                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5280                let excerpt_buffer_end = excerpt
5281                    .range
5282                    .context
5283                    .end
5284                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5285                for (buffer_summary, excerpt_anchor) in excerpt
5286                    .buffer
5287                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5288                        std::iter::from_fn(|| {
5289                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5290                            if !excerpt.contains(&excerpt_anchor) {
5291                                return None;
5292                            }
5293                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5294                        }),
5295                    )
5296                {
5297                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5298                    let mut position = excerpt_start_position;
5299                    if summary > excerpt_buffer_start {
5300                        position += summary - excerpt_buffer_start;
5301                    }
5302
5303                    if diff_transforms_cursor.start().0 < position {
5304                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5305                    }
5306
5307                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5308                        excerpt_anchor,
5309                        position,
5310                        &mut diff_transforms_cursor,
5311                        &excerpt.buffer,
5312                    ));
5313                }
5314            } else {
5315                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5316                let position = self.summary_for_excerpt_position_without_hunks(
5317                    Bias::Right,
5318                    excerpt_start_position,
5319                    &mut diff_transforms_cursor,
5320                );
5321                summaries.push(position);
5322                anchors.next();
5323            }
5324        }
5325
5326        summaries
5327    }
5328
5329    pub fn dimensions_from_points<'a, MBD>(
5330        &'a self,
5331        points: impl 'a + IntoIterator<Item = Point>,
5332    ) -> impl 'a + Iterator<Item = MBD>
5333    where
5334        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5335    {
5336        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5337        cursor.seek(&DimensionPair {
5338            key: Point::default(),
5339            value: None,
5340        });
5341        let mut points = points.into_iter();
5342        iter::from_fn(move || {
5343            let point = points.next()?;
5344
5345            cursor.seek_forward(&DimensionPair {
5346                key: point,
5347                value: None,
5348            });
5349
5350            if let Some(region) = cursor.region() {
5351                let overshoot = point - region.range.start.key;
5352                let buffer_point = region.buffer_range.start + overshoot;
5353                let mut position = region.range.start.value.unwrap();
5354                position.add_text_dim(
5355                    &region
5356                        .buffer
5357                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5358                );
5359                if point == region.range.end.key && region.has_trailing_newline {
5360                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5361                }
5362                Some(position)
5363            } else {
5364                Some(MBD::from_summary(&self.text_summary()))
5365            }
5366        })
5367    }
5368
5369    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5370    where
5371        I: 'a + IntoIterator<Item = &'a Anchor>,
5372    {
5373        let mut anchors = anchors.into_iter().enumerate().peekable();
5374        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5375        cursor.next();
5376
5377        let mut result = Vec::new();
5378
5379        while let Some((_, anchor)) = anchors.peek() {
5380            let old_excerpt_id = anchor.excerpt_id;
5381
5382            // Find the location where this anchor's excerpt should be.
5383            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5384            cursor.seek_forward(&Some(old_locator), Bias::Left);
5385
5386            let next_excerpt = cursor.item();
5387            let prev_excerpt = cursor.prev_item();
5388
5389            // Process all of the anchors for this excerpt.
5390            while let Some((anchor_ix, &anchor)) =
5391                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5392            {
5393                let mut anchor = anchor;
5394
5395                // Leave min and max anchors unchanged if invalid or
5396                // if the old excerpt still exists at this location
5397                let mut kept_position = next_excerpt
5398                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5399                    || old_excerpt_id == ExcerptId::max()
5400                    || old_excerpt_id == ExcerptId::min();
5401
5402                // If the old excerpt no longer exists at this location, then attempt to
5403                // find an equivalent position for this anchor in an adjacent excerpt.
5404                if !kept_position {
5405                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5406                        if excerpt.contains(&anchor) {
5407                            anchor.excerpt_id = excerpt.id;
5408                            kept_position = true;
5409                            break;
5410                        }
5411                    }
5412                }
5413
5414                // If there's no adjacent excerpt that contains the anchor's position,
5415                // then report that the anchor has lost its position.
5416                if !kept_position {
5417                    anchor = if let Some(excerpt) = next_excerpt {
5418                        let mut text_anchor = excerpt
5419                            .range
5420                            .context
5421                            .start
5422                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5423                        if text_anchor
5424                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5425                            .is_gt()
5426                        {
5427                            text_anchor = excerpt.range.context.end;
5428                        }
5429                        Anchor::text(excerpt.id, text_anchor)
5430                    } else if let Some(excerpt) = prev_excerpt {
5431                        let mut text_anchor = excerpt
5432                            .range
5433                            .context
5434                            .end
5435                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5436                        if text_anchor
5437                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5438                            .is_lt()
5439                        {
5440                            text_anchor = excerpt.range.context.start;
5441                        }
5442                        Anchor::text(excerpt.id, text_anchor)
5443                    } else if anchor.text_anchor.bias == Bias::Left {
5444                        Anchor::min()
5445                    } else {
5446                        Anchor::max()
5447                    };
5448                }
5449
5450                result.push((anchor_ix, anchor, kept_position));
5451            }
5452        }
5453        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5454        result
5455    }
5456
5457    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5458        self.anchor_at(position, Bias::Left)
5459    }
5460
5461    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5462        self.anchor_at(position, Bias::Right)
5463    }
5464
5465    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5466        let offset = position.to_offset(self);
5467
5468        // Find the given position in the diff transforms. Determine the corresponding
5469        // offset in the excerpts, and whether the position is within a deleted hunk.
5470        let mut diff_transforms = self
5471            .diff_transforms
5472            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5473        diff_transforms.seek(&offset, Bias::Right);
5474
5475        if offset == diff_transforms.start().0
5476            && bias == Bias::Left
5477            && let Some(prev_item) = diff_transforms.prev_item()
5478            && let DiffTransform::DeletedHunk { .. } = prev_item
5479        {
5480            diff_transforms.prev();
5481        }
5482        let offset_in_transform = offset - diff_transforms.start().0;
5483        let mut excerpt_offset = diff_transforms.start().1;
5484        let mut diff_base_anchor = None;
5485        if let Some(DiffTransform::DeletedHunk {
5486            buffer_id,
5487            base_text_byte_range,
5488            has_trailing_newline,
5489            ..
5490        }) = diff_transforms.item()
5491        {
5492            let diff = self.diffs.get(buffer_id).expect("missing diff");
5493            if offset_in_transform > base_text_byte_range.len() {
5494                debug_assert!(*has_trailing_newline);
5495                bias = Bias::Right;
5496            } else {
5497                diff_base_anchor = Some(
5498                    diff.base_text()
5499                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5500                );
5501                bias = Bias::Left;
5502            }
5503        } else {
5504            excerpt_offset += MultiBufferOffset(offset_in_transform);
5505        };
5506
5507        let mut excerpts = self
5508            .excerpts
5509            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5510        excerpts.seek(&excerpt_offset, Bias::Right);
5511        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5512            excerpts.prev();
5513        }
5514        if let Some(excerpt) = excerpts.item() {
5515            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5516            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5517                overshoot -= 1;
5518                bias = Bias::Right;
5519            }
5520
5521            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5522            let text_anchor =
5523                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5524            let anchor = Anchor::text(excerpt.id, text_anchor);
5525            match diff_base_anchor {
5526                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5527                None => anchor,
5528            }
5529        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5530        {
5531            Anchor::min()
5532        } else {
5533            Anchor::max()
5534        }
5535    }
5536
5537    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5538    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5539        let (excerpt, buffer, _) = self.as_singleton()?;
5540        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5541            Some(Anchor::text(excerpt, text_anchor))
5542        } else {
5543            None
5544        }
5545    }
5546
5547    /// Returns an anchor for the given excerpt and text anchor,
5548    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5549    pub fn anchor_range_in_excerpt(
5550        &self,
5551        excerpt_id: ExcerptId,
5552        text_anchor: Range<text::Anchor>,
5553    ) -> Option<Range<Anchor>> {
5554        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5555
5556        Some(
5557            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5558                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5559        )
5560    }
5561
5562    /// Returns an anchor for the given excerpt and text anchor,
5563    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5564    pub fn anchor_in_excerpt(
5565        &self,
5566        excerpt_id: ExcerptId,
5567        text_anchor: text::Anchor,
5568    ) -> Option<Anchor> {
5569        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5570        Self::anchor_in_excerpt_(excerpt, text_anchor)
5571    }
5572
5573    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5574    pub fn anchors_in_excerpt(
5575        &self,
5576        excerpt_id: ExcerptId,
5577        text_anchors: impl IntoIterator<Item = text::Anchor>,
5578    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5579        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5580        Some(
5581            text_anchors
5582                .into_iter()
5583                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5584        )
5585    }
5586
5587    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5588        match text_anchor.buffer_id {
5589            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5590            Some(_) => return None,
5591            None if text_anchor.is_max() || text_anchor.is_min() => {
5592                return Some(Anchor::text(excerpt.id, text_anchor));
5593            }
5594            None => return None,
5595        }
5596
5597        let context = &excerpt.range.context;
5598        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5599            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5600        {
5601            return None;
5602        }
5603
5604        Some(Anchor::text(excerpt.id, text_anchor))
5605    }
5606
5607    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5608        Some(self.excerpt(excerpt_id)?.range.context.clone())
5609    }
5610
5611    pub fn excerpt_range_for_excerpt(
5612        &self,
5613        excerpt_id: ExcerptId,
5614    ) -> Option<ExcerptRange<text::Anchor>> {
5615        Some(self.excerpt(excerpt_id)?.range.clone())
5616    }
5617
5618    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5619        if anchor.is_min() || anchor.is_max() {
5620            // todo(lw): should be `!self.is_empty()`
5621            true
5622        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5623            excerpt.buffer.can_resolve(&anchor.text_anchor)
5624        } else {
5625            false
5626        }
5627    }
5628
5629    pub fn excerpts(
5630        &self,
5631    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5632        self.excerpts
5633            .iter()
5634            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5635    }
5636
5637    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5638    where
5639        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5640        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5641    {
5642        let excerpts = self.excerpts.cursor(());
5643        let diff_transforms = self.diff_transforms.cursor(());
5644        MultiBufferCursor {
5645            excerpts,
5646            diff_transforms,
5647            diffs: &self.diffs,
5648            cached_region: OnceCell::new(),
5649        }
5650    }
5651
5652    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5653        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5654        let mut excerpts = self
5655            .excerpts
5656            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5657        excerpts.seek(&Some(start_locator), Bias::Left);
5658        excerpts.prev();
5659
5660        let mut diff_transforms = self
5661            .diff_transforms
5662            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5663        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5664        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5665            diff_transforms.next();
5666        }
5667
5668        let excerpt = excerpts.item()?;
5669        Some(MultiBufferExcerpt {
5670            excerpt,
5671            offset: diff_transforms.start().output_dimension.0,
5672            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5673            excerpt_offset: excerpts.start().1,
5674            diff_transforms,
5675        })
5676    }
5677
5678    pub fn excerpt_boundaries_in_range<R, T>(
5679        &self,
5680        range: R,
5681    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5682    where
5683        R: RangeBounds<T>,
5684        T: ToOffset,
5685    {
5686        let start_offset;
5687        let start = match range.start_bound() {
5688            Bound::Included(start) => {
5689                start_offset = start.to_offset(self);
5690                Bound::Included(start_offset)
5691            }
5692            Bound::Excluded(_) => {
5693                panic!("not supported")
5694            }
5695            Bound::Unbounded => {
5696                start_offset = MultiBufferOffset::ZERO;
5697                Bound::Unbounded
5698            }
5699        };
5700        let end = match range.end_bound() {
5701            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5702            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5703            Bound::Unbounded => Bound::Unbounded,
5704        };
5705        let bounds = (start, end);
5706        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5707        cursor.seek(&DimensionPair {
5708            key: start_offset,
5709            value: None,
5710        });
5711
5712        if cursor
5713            .fetch_excerpt_with_range()
5714            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5715        {
5716            cursor.prev_excerpt();
5717        } else {
5718            cursor.seek_to_start_of_current_excerpt();
5719        }
5720        let mut prev_region = cursor
5721            .fetch_excerpt_with_range()
5722            .map(|(excerpt, _)| excerpt);
5723
5724        cursor.next_excerpt_forwards();
5725
5726        iter::from_fn(move || {
5727            loop {
5728                if self.singleton {
5729                    return None;
5730                }
5731
5732                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5733                cursor.next_excerpt_forwards();
5734                if !bounds.contains(&next_range.start.key) {
5735                    prev_region = Some(next_excerpt);
5736                    continue;
5737                }
5738
5739                let next_region_start = next_range.start.value.unwrap();
5740                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5741                    range.start.value.unwrap()
5742                } else {
5743                    self.max_point()
5744                };
5745
5746                let prev = prev_region.as_ref().map(|region| ExcerptBoundaryInfo {
5747                    id: region.id,
5748                    buffer: region.buffer.clone(),
5749                    buffer_id: region.buffer_id,
5750                    range: region.range.clone(),
5751                    end_row: MultiBufferRow(next_region_start.row),
5752                });
5753
5754                let next = ExcerptBoundaryInfo {
5755                    id: next_excerpt.id,
5756                    buffer: next_excerpt.buffer.clone(),
5757                    buffer_id: next_excerpt.buffer_id,
5758                    range: next_excerpt.range.clone(),
5759                    end_row: if next_excerpt.has_trailing_newline {
5760                        MultiBufferRow(next_region_end.row - 1)
5761                    } else {
5762                        MultiBufferRow(next_region_end.row)
5763                    },
5764                };
5765
5766                let row = MultiBufferRow(next_region_start.row);
5767
5768                prev_region = Some(next_excerpt);
5769
5770                return Some(ExcerptBoundary { row, prev, next });
5771            }
5772        })
5773    }
5774
5775    pub fn edit_count(&self) -> usize {
5776        self.edit_count
5777    }
5778
5779    pub fn non_text_state_update_count(&self) -> usize {
5780        self.non_text_state_update_count
5781    }
5782
5783    /// Returns the smallest enclosing bracket ranges containing the given range or
5784    /// None if no brackets contain range or the range is not contained in a single
5785    /// excerpt
5786    ///
5787    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5788    #[ztracing::instrument(skip_all)]
5789    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5790        &self,
5791        range: Range<T>,
5792        range_filter: Option<
5793            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5794        >,
5795    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5796        let range = range.start.to_offset(self)..range.end.to_offset(self);
5797        let mut excerpt = self.excerpt_containing(range.clone())?;
5798        let buffer = excerpt.buffer();
5799        let excerpt_buffer_range = excerpt.buffer_range();
5800
5801        // Filter to ranges contained in the excerpt
5802        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5803            excerpt_buffer_range.contains(&BufferOffset(open.start))
5804                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5805                && range_filter.is_none_or(|filter| {
5806                    filter(
5807                        buffer,
5808                        BufferOffset(open.start)..BufferOffset(close.end),
5809                        BufferOffset(close.start)..BufferOffset(close.end),
5810                    )
5811                })
5812        };
5813
5814        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5815            excerpt.map_range_to_buffer(range),
5816            Some(&range_filter),
5817        )?;
5818
5819        Some((
5820            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5821            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5822        ))
5823    }
5824
5825    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5826    /// not contained in a single excerpt
5827    pub fn enclosing_bracket_ranges<T: ToOffset>(
5828        &self,
5829        range: Range<T>,
5830    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5831    {
5832        let range = range.start.to_offset(self)..range.end.to_offset(self);
5833        let mut excerpt = self.excerpt_containing(range.clone())?;
5834
5835        Some(
5836            excerpt
5837                .buffer()
5838                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5839                .filter_map(move |pair| {
5840                    let open_range =
5841                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5842                    let close_range =
5843                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5844                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5845                        Some((
5846                            excerpt.map_range_from_buffer(open_range),
5847                            excerpt.map_range_from_buffer(close_range),
5848                        ))
5849                    } else {
5850                        None
5851                    }
5852                }),
5853        )
5854    }
5855
5856    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5857    /// not contained in a single excerpt
5858    pub fn text_object_ranges<T: ToOffset>(
5859        &self,
5860        range: Range<T>,
5861        options: TreeSitterOptions,
5862    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5863        let range = range.start.to_offset(self)..range.end.to_offset(self);
5864        self.excerpt_containing(range.clone())
5865            .map(|mut excerpt| {
5866                excerpt
5867                    .buffer()
5868                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5869                    .filter_map(move |(range, text_object)| {
5870                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5871                        if excerpt.contains_buffer_range(range.clone()) {
5872                            Some((excerpt.map_range_from_buffer(range), text_object))
5873                        } else {
5874                            None
5875                        }
5876                    })
5877            })
5878            .into_iter()
5879            .flatten()
5880    }
5881
5882    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5883    /// not contained in a single excerpt
5884    pub fn bracket_ranges<T: ToOffset>(
5885        &self,
5886        range: Range<T>,
5887    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5888    {
5889        let range = range.start.to_offset(self)..range.end.to_offset(self);
5890        let mut excerpt = self.excerpt_containing(range.clone())?;
5891        Some(
5892            excerpt
5893                .buffer()
5894                .bracket_ranges(excerpt.map_range_to_buffer(range))
5895                .filter_map(move |pair| {
5896                    let open_range =
5897                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5898                    let close_range =
5899                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5900                    excerpt
5901                        .contains_buffer_range(open_range.start..close_range.end)
5902                        .then(|| BracketMatch {
5903                            open_range: excerpt.map_range_from_buffer(open_range),
5904                            close_range: excerpt.map_range_from_buffer(close_range),
5905                            color_index: pair.color_index,
5906                            newline_only: pair.newline_only,
5907                            syntax_layer_depth: pair.syntax_layer_depth,
5908                        })
5909                })
5910                .map(BracketMatch::bracket_ranges),
5911        )
5912    }
5913
5914    pub fn redacted_ranges<'a, T: ToOffset>(
5915        &'a self,
5916        range: Range<T>,
5917        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5918    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5919        let range = range.start.to_offset(self)..range.end.to_offset(self);
5920        self.lift_buffer_metadata(range, move |buffer, range| {
5921            if redaction_enabled(buffer.file()) {
5922                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5923            } else {
5924                None
5925            }
5926        })
5927        .map(|(range, _, _)| range)
5928    }
5929
5930    pub fn runnable_ranges(
5931        &self,
5932        range: Range<Anchor>,
5933    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5934        let range = range.start.to_offset(self)..range.end.to_offset(self);
5935        self.lift_buffer_metadata(range, move |buffer, range| {
5936            Some(
5937                buffer
5938                    .runnable_ranges(range.clone())
5939                    .filter(move |runnable| {
5940                        runnable.run_range.start >= range.start
5941                            && runnable.run_range.end < range.end
5942                    })
5943                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5944            )
5945        })
5946        .map(|(run_range, runnable, _)| (run_range, runnable))
5947    }
5948
5949    pub fn line_indents(
5950        &self,
5951        start_row: MultiBufferRow,
5952        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5953    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5954        let max_point = self.max_point();
5955        let mut cursor = self.cursor::<Point, Point>();
5956        cursor.seek(&Point::new(start_row.0, 0));
5957        iter::from_fn(move || {
5958            let mut region = cursor.region()?;
5959            while !buffer_filter(&region.excerpt.buffer) {
5960                cursor.next();
5961                region = cursor.region()?;
5962            }
5963            let region = cursor.region()?;
5964            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5965            let buffer_start_row =
5966                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5967
5968            let buffer_end_row = if region.is_main_buffer
5969                && (region.has_trailing_newline || region.range.end == max_point)
5970            {
5971                region.buffer_range.end.row
5972            } else {
5973                region.buffer_range.end.row.saturating_sub(1)
5974            };
5975
5976            let line_indents = region
5977                .buffer
5978                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5979            let region_buffer_row = region.buffer_range.start.row;
5980            let region_row = region.range.start.row;
5981            let region_buffer = &region.excerpt.buffer;
5982            cursor.next();
5983            Some(line_indents.map(move |(buffer_row, indent)| {
5984                let row = region_row + (buffer_row - region_buffer_row);
5985                (MultiBufferRow(row), indent, region_buffer.as_ref())
5986            }))
5987        })
5988        .flatten()
5989    }
5990
5991    pub fn reversed_line_indents(
5992        &self,
5993        end_row: MultiBufferRow,
5994        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5995    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5996        let max_point = self.max_point();
5997        let mut cursor = self.cursor::<Point, Point>();
5998        cursor.seek(&Point::new(end_row.0, 0));
5999        iter::from_fn(move || {
6000            let mut region = cursor.region()?;
6001            while !buffer_filter(&region.excerpt.buffer) {
6002                cursor.prev();
6003                region = cursor.region()?;
6004            }
6005            let region = cursor.region()?;
6006
6007            let buffer_start_row = region.buffer_range.start.row;
6008            let buffer_end_row = if region.is_main_buffer
6009                && (region.has_trailing_newline || region.range.end == max_point)
6010            {
6011                region.buffer_range.end.row + 1
6012            } else {
6013                region.buffer_range.end.row
6014            };
6015
6016            let overshoot = end_row.0 - region.range.start.row;
6017            let buffer_end_row =
6018                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6019
6020            let line_indents = region
6021                .buffer
6022                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6023            let region_buffer_row = region.buffer_range.start.row;
6024            let region_row = region.range.start.row;
6025            let region_buffer = &region.excerpt.buffer;
6026            cursor.prev();
6027            Some(line_indents.map(move |(buffer_row, indent)| {
6028                let row = region_row + (buffer_row - region_buffer_row);
6029                (MultiBufferRow(row), indent, region_buffer.as_ref())
6030            }))
6031        })
6032        .flatten()
6033    }
6034
6035    pub async fn enclosing_indent(
6036        &self,
6037        mut target_row: MultiBufferRow,
6038    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6039        let max_row = MultiBufferRow(self.max_point().row);
6040        if target_row >= max_row {
6041            return None;
6042        }
6043
6044        let mut target_indent = self.line_indent_for_row(target_row);
6045
6046        // If the current row is at the start of an indented block, we want to return this
6047        // block as the enclosing indent.
6048        if !target_indent.is_line_empty() && target_row < max_row {
6049            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6050            if !next_line_indent.is_line_empty()
6051                && target_indent.raw_len() < next_line_indent.raw_len()
6052            {
6053                target_indent = next_line_indent;
6054                target_row.0 += 1;
6055            }
6056        }
6057
6058        const SEARCH_ROW_LIMIT: u32 = 25000;
6059        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6060        const YIELD_INTERVAL: u32 = 100;
6061
6062        let mut accessed_row_counter = 0;
6063
6064        // If there is a blank line at the current row, search for the next non indented lines
6065        if target_indent.is_line_empty() {
6066            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6067            let end =
6068                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6069
6070            let mut non_empty_line_above = None;
6071            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6072                if row < start {
6073                    break;
6074                }
6075                accessed_row_counter += 1;
6076                if accessed_row_counter == YIELD_INTERVAL {
6077                    accessed_row_counter = 0;
6078                    yield_now().await;
6079                }
6080                if !indent.is_line_empty() {
6081                    non_empty_line_above = Some((row, indent));
6082                    break;
6083                }
6084            }
6085
6086            let mut non_empty_line_below = None;
6087            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6088                if row > end {
6089                    break;
6090                }
6091                accessed_row_counter += 1;
6092                if accessed_row_counter == YIELD_INTERVAL {
6093                    accessed_row_counter = 0;
6094                    yield_now().await;
6095                }
6096                if !indent.is_line_empty() {
6097                    non_empty_line_below = Some((row, indent));
6098                    break;
6099                }
6100            }
6101
6102            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6103                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6104                    if above_indent.raw_len() >= below_indent.raw_len() {
6105                        (above_row, above_indent)
6106                    } else {
6107                        (below_row, below_indent)
6108                    }
6109                }
6110                (Some(above), None) => above,
6111                (None, Some(below)) => below,
6112                _ => return None,
6113            };
6114
6115            target_indent = indent;
6116            target_row = row;
6117        }
6118
6119        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6120        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6121
6122        let mut start_indent = None;
6123        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6124            if row < start {
6125                break;
6126            }
6127            accessed_row_counter += 1;
6128            if accessed_row_counter == YIELD_INTERVAL {
6129                accessed_row_counter = 0;
6130                yield_now().await;
6131            }
6132            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6133                start_indent = Some((row, indent));
6134                break;
6135            }
6136        }
6137        let (start_row, start_indent_size) = start_indent?;
6138
6139        let mut end_indent = (end, None);
6140        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6141            if row > end {
6142                break;
6143            }
6144            accessed_row_counter += 1;
6145            if accessed_row_counter == YIELD_INTERVAL {
6146                accessed_row_counter = 0;
6147                yield_now().await;
6148            }
6149            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6150                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6151                break;
6152            }
6153        }
6154        let (end_row, end_indent_size) = end_indent;
6155
6156        let indent = if let Some(end_indent_size) = end_indent_size {
6157            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6158                start_indent_size
6159            } else {
6160                end_indent_size
6161            }
6162        } else {
6163            start_indent_size
6164        };
6165
6166        Some((start_row..end_row, indent))
6167    }
6168
6169    pub fn indent_guides_in_range<T: ToPoint>(
6170        &self,
6171        range: Range<T>,
6172        ignore_disabled_for_language: bool,
6173        cx: &App,
6174    ) -> impl Iterator<Item = IndentGuide> {
6175        let range = range.start.to_point(self)..range.end.to_point(self);
6176        let start_row = MultiBufferRow(range.start.row);
6177        let end_row = MultiBufferRow(range.end.row);
6178
6179        let mut row_indents = self.line_indents(start_row, |buffer| {
6180            let settings =
6181                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6182            settings.indent_guides.enabled || ignore_disabled_for_language
6183        });
6184
6185        let mut result = Vec::new();
6186        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6187
6188        let mut prev_settings = None;
6189        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6190            if first_row > end_row {
6191                break;
6192            }
6193            let current_depth = indent_stack.len() as u32;
6194
6195            // Avoid retrieving the language settings repeatedly for every buffer row.
6196            if let Some((prev_buffer_id, _)) = &prev_settings
6197                && prev_buffer_id != &buffer.remote_id()
6198            {
6199                prev_settings.take();
6200            }
6201            let settings = &prev_settings
6202                .get_or_insert_with(|| {
6203                    (
6204                        buffer.remote_id(),
6205                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6206                    )
6207                })
6208                .1;
6209            let tab_size = settings.tab_size.get();
6210
6211            // When encountering empty, continue until found useful line indent
6212            // then add to the indent stack with the depth found
6213            let mut found_indent = false;
6214            let mut last_row = first_row;
6215            if line_indent.is_line_blank() {
6216                while !found_indent {
6217                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6218                        break;
6219                    };
6220                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6221                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6222                        break;
6223                    }
6224
6225                    if new_line_indent.is_line_blank() {
6226                        continue;
6227                    }
6228                    last_row = target_row.min(end_row);
6229                    line_indent = new_line_indent;
6230                    found_indent = true;
6231                    break;
6232                }
6233            } else {
6234                found_indent = true
6235            }
6236
6237            let depth = if found_indent {
6238                line_indent.len(tab_size) / tab_size
6239            } else {
6240                0
6241            };
6242
6243            match depth.cmp(&current_depth) {
6244                cmp::Ordering::Less => {
6245                    for _ in 0..(current_depth - depth) {
6246                        let mut indent = indent_stack.pop().unwrap();
6247                        if last_row != first_row {
6248                            // In this case, we landed on an empty row, had to seek forward,
6249                            // and discovered that the indent we where on is ending.
6250                            // This means that the last display row must
6251                            // be on line that ends this indent range, so we
6252                            // should display the range up to the first non-empty line
6253                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6254                        }
6255
6256                        result.push(indent)
6257                    }
6258                }
6259                cmp::Ordering::Greater => {
6260                    for next_depth in current_depth..depth {
6261                        indent_stack.push(IndentGuide {
6262                            buffer_id: buffer.remote_id(),
6263                            start_row: first_row,
6264                            end_row: last_row,
6265                            depth: next_depth,
6266                            tab_size,
6267                            settings: settings.indent_guides.clone(),
6268                        });
6269                    }
6270                }
6271                _ => {}
6272            }
6273
6274            for indent in indent_stack.iter_mut() {
6275                indent.end_row = last_row;
6276            }
6277        }
6278
6279        result.extend(indent_stack);
6280        result.into_iter()
6281    }
6282
6283    pub fn trailing_excerpt_update_count(&self) -> usize {
6284        self.trailing_excerpt_update_count
6285    }
6286
6287    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6288        self.point_to_buffer_offset(point)
6289            .and_then(|(buffer, _)| buffer.file())
6290    }
6291
6292    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6293        self.point_to_buffer_offset(offset)
6294            .and_then(|(buffer, offset)| buffer.language_at(offset))
6295    }
6296
6297    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6298        self.excerpts
6299            .first()
6300            .map(|excerpt| &excerpt.buffer)
6301            .map(|buffer| {
6302                language_settings(
6303                    buffer.language().map(|language| language.name()),
6304                    buffer.file(),
6305                    cx,
6306                )
6307            })
6308            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6309    }
6310
6311    pub fn language_settings_at<'a, T: ToOffset>(
6312        &'a self,
6313        point: T,
6314        cx: &'a App,
6315    ) -> Cow<'a, LanguageSettings> {
6316        let mut language = None;
6317        let mut file = None;
6318        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6319            language = buffer.language_at(offset);
6320            file = buffer.file();
6321        }
6322        language_settings(language.map(|l| l.name()), file, cx)
6323    }
6324
6325    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6326        self.point_to_buffer_offset(point)
6327            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6328    }
6329
6330    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6331        self.point_to_buffer_offset(point)
6332            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6333            .unwrap_or_default()
6334    }
6335
6336    pub fn language_indent_size_at<T: ToOffset>(
6337        &self,
6338        position: T,
6339        cx: &App,
6340    ) -> Option<IndentSize> {
6341        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6342        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6343    }
6344
6345    pub fn is_dirty(&self) -> bool {
6346        self.is_dirty
6347    }
6348
6349    pub fn has_deleted_file(&self) -> bool {
6350        self.has_deleted_file
6351    }
6352
6353    pub fn has_conflict(&self) -> bool {
6354        self.has_conflict
6355    }
6356
6357    pub fn has_diagnostics(&self) -> bool {
6358        self.excerpts
6359            .iter()
6360            .any(|excerpt| excerpt.buffer.has_diagnostics())
6361    }
6362
6363    pub fn diagnostic_group(
6364        &self,
6365        buffer_id: BufferId,
6366        group_id: usize,
6367    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6368        self.lift_buffer_metadata::<Point, _, _>(
6369            Point::zero()..self.max_point(),
6370            move |buffer, range| {
6371                if buffer.remote_id() != buffer_id {
6372                    return None;
6373                };
6374                Some(
6375                    buffer
6376                        .diagnostics_in_range(range, false)
6377                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6378                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6379                )
6380            },
6381        )
6382        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6383    }
6384
6385    pub fn diagnostics_in_range<'a, MBD>(
6386        &'a self,
6387        range: Range<MBD>,
6388    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6389    where
6390        MBD::TextDimension: 'a
6391            + text::ToOffset
6392            + text::FromAnchor
6393            + Sub<Output = MBD::TextDimension>
6394            + fmt::Debug
6395            + ops::Add<Output = MBD::TextDimension>
6396            + ops::AddAssign
6397            + Ord,
6398        MBD: MultiBufferDimension
6399            + Ord
6400            + Sub<Output = MBD::TextDimension>
6401            + ops::Add<MBD::TextDimension, Output = MBD>
6402            + ops::AddAssign<MBD::TextDimension>
6403            + 'a,
6404    {
6405        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6406            Some(
6407                buffer
6408                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6409                    .map(|entry| (entry.range, entry.diagnostic)),
6410            )
6411        })
6412        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6413    }
6414
6415    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6416        &'a self,
6417        range: Range<MBD>,
6418    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6419    where
6420        MBD: MultiBufferDimension
6421            + Ord
6422            + Sub<Output = MBD::TextDimension>
6423            + ops::Add<MBD::TextDimension, Output = MBD>
6424            + ops::AddAssign<MBD::TextDimension>,
6425        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6426            + ops::Add<Output = MBD::TextDimension>
6427            + text::ToOffset
6428            + text::FromAnchor
6429            + AddAssign<MBD::TextDimension>
6430            + Ord,
6431    {
6432        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6433            Some(
6434                buffer
6435                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6436                    .map(|entry| (entry.range, entry.diagnostic)),
6437            )
6438        })
6439        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6440    }
6441
6442    pub fn syntax_ancestor<T: ToOffset>(
6443        &self,
6444        range: Range<T>,
6445    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6446        let range = range.start.to_offset(self)..range.end.to_offset(self);
6447        let mut excerpt = self.excerpt_containing(range.clone())?;
6448        let node = excerpt
6449            .buffer()
6450            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6451        let node_range = node.byte_range();
6452        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6453        if !excerpt.contains_buffer_range(node_range.clone()) {
6454            return None;
6455        };
6456        Some((node, excerpt.map_range_from_buffer(node_range)))
6457    }
6458
6459    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6460        let (excerpt_id, _, buffer) = self.as_singleton()?;
6461        let outline = buffer.outline(theme);
6462        Some(Outline::new(
6463            outline
6464                .items
6465                .into_iter()
6466                .flat_map(|item| {
6467                    Some(OutlineItem {
6468                        depth: item.depth,
6469                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6470                        source_range_for_text: self
6471                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6472                        text: item.text,
6473                        highlight_ranges: item.highlight_ranges,
6474                        name_ranges: item.name_ranges,
6475                        body_range: item.body_range.and_then(|body_range| {
6476                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6477                        }),
6478                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6479                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6480                        }),
6481                    })
6482                })
6483                .collect(),
6484        ))
6485    }
6486
6487    pub fn symbols_containing<T: ToOffset>(
6488        &self,
6489        offset: T,
6490        theme: Option<&SyntaxTheme>,
6491    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6492        let anchor = self.anchor_before(offset);
6493        let excerpt @ &Excerpt {
6494            id: excerpt_id,
6495            buffer_id,
6496            ref buffer,
6497            ..
6498        } = self.excerpt(anchor.excerpt_id)?;
6499        if cfg!(debug_assertions) {
6500            match anchor.text_anchor.buffer_id {
6501                // we clearly are hitting this according to sentry, but in what situations can this occur?
6502                Some(anchor_buffer_id) => {
6503                    assert_eq!(
6504                        anchor_buffer_id, buffer_id,
6505                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6506                    )
6507                }
6508                None => assert!(anchor.is_max()),
6509            }
6510        };
6511        Some((
6512            buffer_id,
6513            buffer
6514                .symbols_containing(anchor.text_anchor, theme)
6515                .into_iter()
6516                .flat_map(|item| {
6517                    Some(OutlineItem {
6518                        depth: item.depth,
6519                        source_range_for_text: Anchor::range_in_buffer(
6520                            excerpt_id,
6521                            item.source_range_for_text,
6522                        ),
6523                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6524                        text: item.text,
6525                        highlight_ranges: item.highlight_ranges,
6526                        name_ranges: item.name_ranges,
6527                        body_range: item
6528                            .body_range
6529                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6530                        annotation_range: item
6531                            .annotation_range
6532                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6533                    })
6534                })
6535                .collect(),
6536        ))
6537    }
6538
6539    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6540        self.try_excerpt_locator_for_id(id)
6541            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6542    }
6543
6544    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6545        if id == ExcerptId::min() {
6546            Some(Locator::min_ref())
6547        } else if id == ExcerptId::max() {
6548            Some(Locator::max_ref())
6549        } else {
6550            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6551            if let Some(entry) = item
6552                && entry.id == id
6553            {
6554                return Some(&entry.locator);
6555            }
6556            None
6557        }
6558    }
6559
6560    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6561    fn excerpt_locators_for_ids(
6562        &self,
6563        ids: impl IntoIterator<Item = ExcerptId>,
6564    ) -> SmallVec<[Locator; 1]> {
6565        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6566        sorted_ids.sort_unstable();
6567        sorted_ids.dedup();
6568        let mut locators = SmallVec::new();
6569
6570        while sorted_ids.last() == Some(&ExcerptId::max()) {
6571            sorted_ids.pop();
6572            locators.push(Locator::max());
6573        }
6574
6575        let mut sorted_ids = sorted_ids.into_iter().peekable();
6576        locators.extend(
6577            sorted_ids
6578                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6579                .map(|_| Locator::min()),
6580        );
6581
6582        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6583        for id in sorted_ids {
6584            if cursor.seek_forward(&id, Bias::Left) {
6585                locators.push(cursor.item().unwrap().locator.clone());
6586            } else {
6587                panic!("invalid excerpt id {:?}", id);
6588            }
6589        }
6590
6591        locators.sort_unstable();
6592        locators
6593    }
6594
6595    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6596        Some(self.excerpt(excerpt_id)?.buffer_id)
6597    }
6598
6599    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6600        Some(&self.excerpt(excerpt_id)?.buffer)
6601    }
6602
6603    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6604        todo!()
6605    }
6606
6607    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6608        self.path_keys_by_buffer.get(&buffer_id)
6609    }
6610
6611    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6612        self.buffer_for_path(self.path_keys_by_buffer.get(&id)?)
6613    }
6614
6615    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6616        self.path_keys_by_index.get(&anchor.path).cloned()
6617    }
6618
6619    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6620        self.try_path_for_anchor(anchor)
6621            .expect("invalid anchor: path was never added to multibuffer")
6622    }
6623
6624    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6625        let mut cursor = self
6626            .excerpts
6627            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6628        let locator = self.excerpt_locator_for_id(excerpt_id);
6629        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6630        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6631            sought_exact = true;
6632            cursor.prev();
6633        } else if excerpt_id == ExcerptId::min() {
6634            sought_exact = true;
6635        }
6636        if sought_exact {
6637            let start = cursor.start().1;
6638            let end = cursor.end().1;
6639            let mut diff_transforms = self
6640                .diff_transforms
6641                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6642            diff_transforms.seek(&start, Bias::Left);
6643            let overshoot = start - diff_transforms.start().0;
6644            let start = diff_transforms.start().1 + overshoot;
6645            diff_transforms.seek(&end, Bias::Right);
6646            let overshoot = end - diff_transforms.start().0;
6647            let end = diff_transforms.start().1 + overshoot;
6648            Some(start.0..end.0)
6649        } else {
6650            None
6651        }
6652    }
6653
6654    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6655    /// to have the latest excerpt id for the one passed in and will also remap
6656    /// `ExcerptId::max()` to the corresponding excertp ID.
6657    ///
6658    /// Callers of this function should generally use the resulting excerpt's `id` field
6659    /// afterwards.
6660    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6661        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6662        let locator = self.try_excerpt_locator_for_id(excerpt_id)?;
6663        let (_, _, item) =
6664            self.excerpts
6665                .find::<Option<&Locator>, _>((), &Some(locator), Bias::Left);
6666        if let Some(excerpt) = item
6667            && excerpt.id == excerpt_id
6668        {
6669            return Some(excerpt);
6670        } else if item.is_none() && excerpt_id == ExcerptId::max() {
6671            return self.excerpts.last();
6672        }
6673        None
6674    }
6675
6676    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6677    pub fn excerpt_containing<T: ToOffset>(
6678        &self,
6679        range: Range<T>,
6680    ) -> Option<MultiBufferExcerpt<'_>> {
6681        let range = range.start.to_offset(self)..range.end.to_offset(self);
6682        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6683        cursor.seek(&range.start);
6684
6685        let start_excerpt = cursor.excerpt()?;
6686        if range.end != range.start {
6687            cursor.seek_forward(&range.end);
6688            if cursor.excerpt()?.id != start_excerpt.id {
6689                return None;
6690            }
6691        }
6692
6693        cursor.seek_to_start_of_current_excerpt();
6694        let region = cursor.region()?;
6695        let offset = region.range.start;
6696        let buffer_offset = start_excerpt.buffer_start_offset();
6697        let excerpt_offset = *cursor.excerpts.start();
6698        Some(MultiBufferExcerpt {
6699            diff_transforms: cursor.diff_transforms,
6700            excerpt: start_excerpt,
6701            offset,
6702            buffer_offset,
6703            excerpt_offset,
6704        })
6705    }
6706
6707    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6708        if let Some(id) = anchor.text_anchor.buffer_id {
6709            return Some(id);
6710        }
6711        let excerpt = self.excerpt_containing(anchor..anchor)?;
6712        Some(excerpt.buffer_id())
6713    }
6714
6715    pub fn selections_in_range<'a>(
6716        &'a self,
6717        range: &'a Range<Anchor>,
6718        include_local: bool,
6719    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6720        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6721        cursor.seek(&range.start.seek_target(self), Bias::Left);
6722        cursor
6723            .take_while(move |excerpt| {
6724                let excerpt_start =
6725                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6726                excerpt_start.cmp(&range.end, self).is_le()
6727            })
6728            .flat_map(move |excerpt| {
6729                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6730                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6731                    && excerpt.contains(&excerpt_anchor)
6732                {
6733                    query_range.start = excerpt_anchor.text_anchor();
6734                }
6735                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6736                    && excerpt.contains(&excerpt_anchor)
6737                {
6738                    query_range.end = excerpt_anchor.text_anchor();
6739                }
6740
6741                excerpt
6742                    .buffer
6743                    .selections_in_range(query_range, include_local)
6744                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6745                        selections.map(move |selection| {
6746                            let mut start =
6747                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6748                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6749                            if range.start.cmp(&start, self).is_gt() {
6750                                start = range.start;
6751                            }
6752                            if range.end.cmp(&end, self).is_lt() {
6753                                end = range.end;
6754                            }
6755
6756                            (
6757                                replica_id,
6758                                line_mode,
6759                                cursor_shape,
6760                                Selection {
6761                                    id: selection.id,
6762                                    start,
6763                                    end,
6764                                    reversed: selection.reversed,
6765                                    goal: selection.goal,
6766                                },
6767                            )
6768                        })
6769                    })
6770            })
6771    }
6772
6773    pub fn show_headers(&self) -> bool {
6774        self.show_headers
6775    }
6776
6777    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6778        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6779    }
6780
6781    pub fn all_diff_hunks_expanded(&self) -> bool {
6782        self.all_diff_hunks_expanded
6783    }
6784
6785    /// Visually annotates a position or range with the `Debug` representation of a value. The
6786    /// callsite of this function is used as a key - previous annotations will be removed.
6787    #[cfg(debug_assertions)]
6788    #[track_caller]
6789    pub fn debug<V, R>(&self, ranges: &R, value: V)
6790    where
6791        R: debug::ToMultiBufferDebugRanges,
6792        V: std::fmt::Debug,
6793    {
6794        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6795    }
6796
6797    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6798    /// debug annotations with the same key will be removed. The key is also used to determine the
6799    /// annotation's color.
6800    #[cfg(debug_assertions)]
6801    #[track_caller]
6802    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6803    where
6804        K: std::hash::Hash + 'static,
6805        R: debug::ToMultiBufferDebugRanges,
6806        V: std::fmt::Debug,
6807    {
6808        let text_ranges = ranges
6809            .to_multi_buffer_debug_ranges(self)
6810            .into_iter()
6811            .flat_map(|range| {
6812                self.range_to_buffer_ranges(range.start..=range.end)
6813                    .into_iter()
6814                    .map(|(buffer, range, _excerpt_id)| {
6815                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6816                    })
6817            })
6818            .collect();
6819        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6820            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6821        });
6822    }
6823
6824    fn excerpt_edits_for_diff_change(
6825        &self,
6826        buffer_state: &BufferState,
6827        diff_change_range: Range<usize>,
6828    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6829        let mut excerpt_edits = Vec::new();
6830        for locator in &buffer_state.excerpts {
6831            let mut cursor = self
6832                .excerpts
6833                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6834            cursor.seek_forward(&Some(locator), Bias::Left);
6835            if let Some(excerpt) = cursor.item()
6836                && excerpt.locator == *locator
6837            {
6838                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6839                if diff_change_range.end < excerpt_buffer_range.start
6840                    || diff_change_range.start > excerpt_buffer_range.end
6841                {
6842                    continue;
6843                }
6844                let excerpt_start = cursor.start().1;
6845                let excerpt_len = excerpt.text_summary.len;
6846                let diff_change_start_in_excerpt = diff_change_range
6847                    .start
6848                    .saturating_sub(excerpt_buffer_range.start);
6849                let diff_change_end_in_excerpt = diff_change_range
6850                    .end
6851                    .saturating_sub(excerpt_buffer_range.start);
6852                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
6853                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
6854                excerpt_edits.push(Edit {
6855                    old: edit_start..edit_end,
6856                    new: edit_start..edit_end,
6857                });
6858            }
6859        }
6860        excerpt_edits
6861    }
6862
6863    fn excerpt_ranges_for_path(
6864        &self,
6865        path_key: &PathKey,
6866    ) -> impl Iterator<Item = ExcerptRange<text::Anchor>> {
6867        todo!()
6868    }
6869}
6870
6871#[cfg(any(test, feature = "test-support"))]
6872impl MultiBufferSnapshot {
6873    pub fn random_byte_range(
6874        &self,
6875        start_offset: MultiBufferOffset,
6876        rng: &mut impl rand::Rng,
6877    ) -> Range<MultiBufferOffset> {
6878        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6879        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6880        start..end
6881    }
6882
6883    #[cfg(any(test, feature = "test-support"))]
6884    fn check_invariants(&self) {
6885        let excerpts = self.excerpts.items(());
6886        let excerpt_ids = self.excerpt_ids.items(());
6887
6888        for (ix, excerpt) in excerpts.iter().enumerate() {
6889            if ix == 0 {
6890                if excerpt.locator <= Locator::min() {
6891                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6892                }
6893            } else if excerpt.locator <= excerpts[ix - 1].locator {
6894                panic!("excerpts are out-of-order: {:?}", excerpts);
6895            }
6896        }
6897
6898        for (ix, entry) in excerpt_ids.iter().enumerate() {
6899            if ix == 0 {
6900                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6901                    panic!("invalid first excerpt id {:?}", entry.id);
6902                }
6903            } else if entry.id <= excerpt_ids[ix - 1].id {
6904                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6905            }
6906        }
6907
6908        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6909            panic!(
6910                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6911                self.excerpts.summary().text,
6912                self.diff_transforms.summary().input,
6913                self.diff_transforms.items(()),
6914            );
6915        }
6916
6917        let mut prev_transform: Option<&DiffTransform> = None;
6918        for item in self.diff_transforms.iter() {
6919            if let DiffTransform::BufferContent {
6920                summary,
6921                inserted_hunk_info,
6922            } = item
6923            {
6924                if let Some(DiffTransform::BufferContent {
6925                    inserted_hunk_info: prev_inserted_hunk_info,
6926                    ..
6927                }) = prev_transform
6928                    && *inserted_hunk_info == *prev_inserted_hunk_info
6929                {
6930                    panic!(
6931                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6932                        self.diff_transforms.items(())
6933                    );
6934                }
6935                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6936                    panic!("empty buffer content transform");
6937                }
6938            }
6939            prev_transform = Some(item);
6940        }
6941    }
6942}
6943
6944impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6945where
6946    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6947    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6948{
6949    #[instrument(skip_all)]
6950    fn seek(&mut self, position: &MBD) {
6951        let position = OutputDimension(*position);
6952        self.cached_region.take();
6953        self.diff_transforms.seek(&position, Bias::Right);
6954        if self.diff_transforms.item().is_none()
6955            && self.diff_transforms.start().output_dimension == position
6956        {
6957            self.diff_transforms.prev();
6958        }
6959
6960        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6961        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6962            let overshoot = position - self.diff_transforms.start().output_dimension;
6963            excerpt_position += overshoot;
6964        }
6965
6966        self.excerpts.seek(&excerpt_position, Bias::Right);
6967        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6968            self.excerpts.prev();
6969        }
6970    }
6971
6972    fn seek_forward(&mut self, position: &MBD) {
6973        let position = OutputDimension(*position);
6974        self.cached_region.take();
6975        self.diff_transforms.seek_forward(&position, Bias::Right);
6976        if self.diff_transforms.item().is_none()
6977            && self.diff_transforms.start().output_dimension == position
6978        {
6979            self.diff_transforms.prev();
6980        }
6981
6982        let overshoot = position - self.diff_transforms.start().output_dimension;
6983        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6984        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6985            excerpt_position += overshoot;
6986        }
6987
6988        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6989        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6990            self.excerpts.prev();
6991        }
6992    }
6993
6994    fn next_excerpt(&mut self) {
6995        self.excerpts.next();
6996        self.seek_to_start_of_current_excerpt();
6997    }
6998
6999    fn prev_excerpt(&mut self) {
7000        self.excerpts.prev();
7001        self.seek_to_start_of_current_excerpt();
7002    }
7003
7004    fn seek_to_start_of_current_excerpt(&mut self) {
7005        self.cached_region.take();
7006
7007        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7008            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7009            && self.diff_transforms.next_item().is_some()
7010        {
7011            self.diff_transforms.next();
7012        }
7013    }
7014
7015    fn next_excerpt_forwards(&mut self) {
7016        self.excerpts.next();
7017        self.seek_to_start_of_current_excerpt_forward();
7018    }
7019
7020    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7021        self.cached_region.take();
7022
7023        if self
7024            .diff_transforms
7025            .seek_forward(self.excerpts.start(), Bias::Left)
7026            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7027            && self.diff_transforms.next_item().is_some()
7028        {
7029            self.diff_transforms.next();
7030        }
7031    }
7032
7033    fn next(&mut self) {
7034        self.cached_region.take();
7035        match self
7036            .diff_transforms
7037            .end()
7038            .excerpt_dimension
7039            .cmp(&self.excerpts.end())
7040        {
7041            cmp::Ordering::Less => self.diff_transforms.next(),
7042            cmp::Ordering::Greater => self.excerpts.next(),
7043            cmp::Ordering::Equal => {
7044                self.diff_transforms.next();
7045                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7046                    || self.diff_transforms.item().is_none()
7047                {
7048                    self.excerpts.next();
7049                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7050                    self.diff_transforms.item()
7051                    && self
7052                        .excerpts
7053                        .item()
7054                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7055                {
7056                    self.excerpts.next();
7057                }
7058            }
7059        }
7060    }
7061
7062    fn prev(&mut self) {
7063        self.cached_region.take();
7064        match self
7065            .diff_transforms
7066            .start()
7067            .excerpt_dimension
7068            .cmp(self.excerpts.start())
7069        {
7070            cmp::Ordering::Less => self.excerpts.prev(),
7071            cmp::Ordering::Greater => self.diff_transforms.prev(),
7072            cmp::Ordering::Equal => {
7073                self.diff_transforms.prev();
7074                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7075                    || self.diff_transforms.item().is_none()
7076                {
7077                    self.excerpts.prev();
7078                }
7079            }
7080        }
7081    }
7082
7083    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7084        self.cached_region
7085            .get_or_init(|| self.build_region())
7086            .as_ref()
7087    }
7088
7089    fn is_at_start_of_excerpt(&mut self) -> bool {
7090        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7091            return false;
7092        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7093            return true;
7094        }
7095
7096        self.diff_transforms.prev();
7097        let prev_transform = self.diff_transforms.item();
7098        self.diff_transforms.next();
7099
7100        prev_transform.is_none_or(|next_transform| {
7101            matches!(next_transform, DiffTransform::BufferContent { .. })
7102        })
7103    }
7104
7105    fn is_at_end_of_excerpt(&self) -> bool {
7106        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7107            return false;
7108        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7109            || self.diff_transforms.item().is_none()
7110        {
7111            return true;
7112        }
7113
7114        let next_transform = self.diff_transforms.next_item();
7115        next_transform.is_none_or(|next_transform| match next_transform {
7116            DiffTransform::BufferContent { .. } => true,
7117            DiffTransform::DeletedHunk { hunk_info, .. } => self
7118                .excerpts
7119                .item()
7120                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7121        })
7122    }
7123
7124    fn main_buffer_position(&self) -> Option<BD> {
7125        let excerpt = self.excerpts.item()?;
7126        let buffer = &excerpt.buffer;
7127        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7128        let mut buffer_start = buffer_context_start;
7129        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7130        buffer_start += overshoot;
7131        Some(buffer_start)
7132    }
7133
7134    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7135        let excerpt = self.excerpts.item()?;
7136        match self.diff_transforms.item()? {
7137            DiffTransform::DeletedHunk {
7138                buffer_id,
7139                base_text_byte_range,
7140                has_trailing_newline,
7141                hunk_info,
7142                ..
7143            } => {
7144                let diff = self.diffs.get(buffer_id)?;
7145                let buffer = diff.base_text();
7146                let mut rope_cursor = buffer.as_rope().cursor(0);
7147                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7148                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7149                let mut buffer_end = buffer_start;
7150                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7151                let start = self.diff_transforms.start().output_dimension.0;
7152                let end = self.diff_transforms.end().output_dimension.0;
7153                Some(MultiBufferRegion {
7154                    buffer,
7155                    excerpt,
7156                    has_trailing_newline: *has_trailing_newline,
7157                    is_main_buffer: false,
7158                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7159                        hunk_info.hunk_secondary_status,
7160                    )),
7161                    buffer_range: buffer_start..buffer_end,
7162                    range: start..end,
7163                })
7164            }
7165            DiffTransform::BufferContent {
7166                inserted_hunk_info, ..
7167            } => {
7168                let buffer = &excerpt.buffer;
7169                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7170
7171                let mut start = self.diff_transforms.start().output_dimension.0;
7172                let mut buffer_start = buffer_context_start;
7173                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7174                    let overshoot =
7175                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7176                    start += overshoot;
7177                } else {
7178                    let overshoot =
7179                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7180                    buffer_start += overshoot;
7181                }
7182
7183                let mut end;
7184                let mut buffer_end;
7185                let has_trailing_newline;
7186                let transform_end = self.diff_transforms.end();
7187                if transform_end.excerpt_dimension < self.excerpts.end() {
7188                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7189                    end = transform_end.output_dimension.0;
7190                    buffer_end = buffer_context_start;
7191                    buffer_end += overshoot;
7192                    has_trailing_newline = false;
7193                } else {
7194                    let overshoot =
7195                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7196                    end = self.diff_transforms.start().output_dimension.0;
7197                    end += overshoot;
7198                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7199                    has_trailing_newline = excerpt.has_trailing_newline;
7200                };
7201
7202                let diff_hunk_status = inserted_hunk_info.map(|info| {
7203                    if info.is_logically_deleted {
7204                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7205                    } else {
7206                        DiffHunkStatus::added(info.hunk_secondary_status)
7207                    }
7208                });
7209
7210                Some(MultiBufferRegion {
7211                    buffer,
7212                    excerpt,
7213                    has_trailing_newline,
7214                    is_main_buffer: true,
7215                    diff_hunk_status,
7216                    buffer_range: buffer_start..buffer_end,
7217                    range: start..end,
7218                })
7219            }
7220        }
7221    }
7222
7223    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7224        let excerpt = self.excerpts.item()?;
7225        match self.diff_transforms.item()? {
7226            &DiffTransform::DeletedHunk { .. } => {
7227                let start = self.diff_transforms.start().output_dimension.0;
7228                let end = self.diff_transforms.end().output_dimension.0;
7229                Some((excerpt, start..end))
7230            }
7231            DiffTransform::BufferContent { .. } => {
7232                let mut start = self.diff_transforms.start().output_dimension.0;
7233                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7234                    let overshoot =
7235                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7236                    start += overshoot;
7237                }
7238
7239                let mut end;
7240                let transform_end = self.diff_transforms.end();
7241                if transform_end.excerpt_dimension < self.excerpts.end() {
7242                    end = transform_end.output_dimension.0;
7243                } else {
7244                    let overshoot =
7245                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7246                    end = self.diff_transforms.start().output_dimension.0;
7247                    end += overshoot;
7248                };
7249
7250                Some((excerpt, start..end))
7251            }
7252        }
7253    }
7254
7255    fn excerpt(&self) -> Option<&'a Excerpt> {
7256        self.excerpts.item()
7257    }
7258}
7259
7260impl Excerpt {
7261    fn new(
7262        path_key: PathKey,
7263        buffer: Arc<BufferSnapshot>,
7264        range: ExcerptRange<text::Anchor>,
7265        has_trailing_newline: bool,
7266    ) -> Self {
7267        Excerpt {
7268            path_key,
7269            max_buffer_row: range.context.end.to_point(&buffer).row,
7270            text_summary: buffer
7271                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7272            buffer,
7273            range,
7274            has_trailing_newline,
7275        }
7276    }
7277
7278    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7279        let content_start = self.range.context.start.to_offset(&self.buffer);
7280        let chunks_start = content_start + range.start;
7281        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7282
7283        let has_footer = self.has_trailing_newline
7284            && range.start <= self.text_summary.len
7285            && range.end > self.text_summary.len;
7286
7287        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7288
7289        ExcerptChunks {
7290            content_chunks,
7291            has_footer,
7292        }
7293    }
7294
7295    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7296        let content_start = self.range.context.start.to_offset(&self.buffer);
7297        let chunks_start = content_start + range.start;
7298        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7299        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7300        excerpt_chunks.has_footer = self.has_trailing_newline
7301            && range.start <= self.text_summary.len
7302            && range.end > self.text_summary.len;
7303    }
7304
7305    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7306        if text_anchor
7307            .cmp(&self.range.context.start, &self.buffer)
7308            .is_lt()
7309        {
7310            self.range.context.start
7311        } else if text_anchor
7312            .cmp(&self.range.context.end, &self.buffer)
7313            .is_gt()
7314        {
7315            self.range.context.end
7316        } else {
7317            text_anchor
7318        }
7319    }
7320
7321    pub(crate) fn contains(&self, anchor: &ExcerptAnchor) -> bool {
7322        self.path_key_index == anchor.path
7323            && self.buffer.remote_id() == anchor.buffer_id
7324            && self.range.contains(&anchor.text_anchor(), &self.buffer)
7325    }
7326
7327    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7328    fn buffer_start_offset(&self) -> BufferOffset {
7329        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7330    }
7331
7332    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7333    fn buffer_end_offset(&self) -> BufferOffset {
7334        self.buffer_start_offset() + self.text_summary.len
7335    }
7336}
7337
7338impl PartialEq for Excerpt {
7339    fn eq(&self, other: &Self) -> bool {
7340        self.buffer.remote_id() == other.buffer.remote_id()
7341            && self.range.context == other.range.context
7342    }
7343}
7344
7345impl<'a> MultiBufferExcerpt<'a> {
7346    pub fn id(&self) -> ExcerptId {
7347        self.excerpt.id
7348    }
7349
7350    pub fn buffer_id(&self) -> BufferId {
7351        self.excerpt.buffer_id
7352    }
7353
7354    pub fn start_anchor(&self) -> Anchor {
7355        Anchor::text(self.excerpt.id, self.excerpt.range.context.start)
7356    }
7357
7358    pub fn end_anchor(&self) -> Anchor {
7359        Anchor::text(self.excerpt.id, self.excerpt.range.context.end)
7360    }
7361
7362    pub fn buffer(&self) -> &'a BufferSnapshot {
7363        &self.excerpt.buffer
7364    }
7365
7366    pub fn buffer_range(&self) -> Range<BufferOffset> {
7367        self.buffer_offset
7368            ..BufferOffset(
7369                self.excerpt
7370                    .range
7371                    .context
7372                    .end
7373                    .to_offset(&self.excerpt.buffer.text),
7374            )
7375    }
7376
7377    pub fn start_offset(&self) -> MultiBufferOffset {
7378        self.offset
7379    }
7380
7381    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7382    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7383        self.map_range_to_buffer(offset..offset).start
7384    }
7385
7386    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7387    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7388        self.diff_transforms
7389            .seek(&OutputDimension(range.start), Bias::Right);
7390        let start = self.map_offset_to_buffer_internal(range.start);
7391        let end = if range.end > range.start {
7392            self.diff_transforms
7393                .seek_forward(&OutputDimension(range.end), Bias::Right);
7394            self.map_offset_to_buffer_internal(range.end)
7395        } else {
7396            start
7397        };
7398        start..end
7399    }
7400
7401    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7402        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7403        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7404            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7405        };
7406        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7407        self.buffer_offset + offset_in_excerpt
7408    }
7409
7410    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7411    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7412        self.map_range_from_buffer(buffer_offset..buffer_offset)
7413            .start
7414    }
7415
7416    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7417    pub fn map_range_from_buffer(
7418        &mut self,
7419        buffer_range: Range<BufferOffset>,
7420    ) -> Range<MultiBufferOffset> {
7421        if buffer_range.start < self.buffer_offset {
7422            log::warn!(
7423                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7424            );
7425            return self.offset..self.offset;
7426        }
7427        let overshoot = buffer_range.start - self.buffer_offset;
7428        let excerpt_offset = self.excerpt_offset + overshoot;
7429        let excerpt_seek_dim = excerpt_offset;
7430        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7431        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7432            log::warn!(
7433                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7434            );
7435            return self.offset..self.offset;
7436        }
7437        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7438        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7439
7440        let end = if buffer_range.start < buffer_range.end {
7441            let overshoot = buffer_range.end - self.buffer_offset;
7442            let excerpt_offset = self.excerpt_offset + overshoot;
7443            let excerpt_seek_dim = excerpt_offset;
7444            self.diff_transforms
7445                .seek_forward(&excerpt_seek_dim, Bias::Right);
7446            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7447            // todo(lw): Clamp end to the excerpt boundaries
7448            self.diff_transforms.start().output_dimension.0 + overshoot
7449        } else {
7450            start
7451        };
7452
7453        start..end
7454    }
7455
7456    /// Returns true if the entirety of the given range is in the buffer's excerpt
7457    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7458        range.start >= self.excerpt.buffer_start_offset()
7459            && range.end <= self.excerpt.buffer_end_offset()
7460    }
7461
7462    /// Returns true if any part of the given range is in the buffer's excerpt
7463    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7464        range.start <= self.excerpt.buffer_end_offset()
7465            && range.end >= self.excerpt.buffer_start_offset()
7466    }
7467
7468    pub fn max_buffer_row(&self) -> u32 {
7469        self.excerpt.max_buffer_row
7470    }
7471}
7472
7473impl fmt::Debug for Excerpt {
7474    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7475        f.debug_struct("Excerpt")
7476            .field("path_key", &self.path_key)
7477            .field("range", &self.range)
7478            .field("text_summary", &self.text_summary)
7479            .field("has_trailing_newline", &self.has_trailing_newline)
7480            .finish()
7481    }
7482}
7483
7484impl sum_tree::Item for Excerpt {
7485    type Summary = ExcerptSummary;
7486
7487    fn summary(&self, _cx: ()) -> Self::Summary {
7488        let mut text = self.text_summary;
7489        if self.has_trailing_newline {
7490            text += TextSummary::from("\n");
7491        }
7492        ExcerptSummary {
7493            path_key: self.path_key,
7494            max_anchor: self.range.context.end,
7495            widest_line_number: self.max_buffer_row,
7496            text: text.into(),
7497            count: 1,
7498        }
7499    }
7500}
7501
7502impl DiffTransform {
7503    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7504        match self {
7505            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7506            DiffTransform::BufferContent {
7507                inserted_hunk_info, ..
7508            } => *inserted_hunk_info,
7509        }
7510    }
7511}
7512
7513impl sum_tree::Item for DiffTransform {
7514    type Summary = DiffTransformSummary;
7515
7516    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7517        match self {
7518            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7519                input: *summary,
7520                output: *summary,
7521            },
7522            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7523                input: MBTextSummary::default(),
7524                output: summary.into(),
7525            },
7526        }
7527    }
7528}
7529
7530impl DiffTransformSummary {
7531    fn excerpt_len(&self) -> ExcerptOffset {
7532        ExcerptDimension(self.input.len)
7533    }
7534}
7535
7536impl sum_tree::ContextLessSummary for DiffTransformSummary {
7537    fn zero() -> Self {
7538        DiffTransformSummary {
7539            input: MBTextSummary::default(),
7540            output: MBTextSummary::default(),
7541        }
7542    }
7543
7544    fn add_summary(&mut self, other: &Self) {
7545        self.input += other.input;
7546        self.output += other.output;
7547    }
7548}
7549
7550impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7551    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7552        PathKey::min()
7553    }
7554
7555    fn add_summary(
7556        &mut self,
7557        summary: &'_ ExcerptSummary,
7558        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7559    ) {
7560        *self = summary.path_key.clone();
7561    }
7562}
7563
7564impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7565    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7566        MultiBufferOffset::ZERO
7567    }
7568
7569    fn add_summary(
7570        &mut self,
7571        summary: &'_ ExcerptSummary,
7572        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7573    ) {
7574        self += summary.text.len
7575    }
7576}
7577
7578impl sum_tree::ContextLessSummary for ExcerptSummary {
7579    fn zero() -> Self {
7580        Self::min()
7581    }
7582
7583    fn add_summary(&mut self, summary: &Self) {
7584        debug_assert!(
7585            summary.path_key >= self.path_key,
7586            "Path keys must be in ascending order: {:?} > {:?}",
7587            summary.path_key,
7588            self.path_key
7589        );
7590
7591        self.path_key = summary.path_key.clone();
7592        self.max_anchor = summary.max_anchor;
7593        self.text += summary.text;
7594        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7595        self.count += summary.count;
7596    }
7597}
7598
7599impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7600    fn cmp(
7601        &self,
7602        cursor_location: &ExcerptSummary,
7603        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7604    ) -> cmp::Ordering {
7605        match self {
7606            AnchorSeekTarget::Min => Ordering::Less,
7607            AnchorSeekTarget::Max => Ordering::Greater,
7608            AnchorSeekTarget::Excerpt {
7609                path_key,
7610                anchor,
7611                snapshot,
7612            } => {
7613                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7614                if path_comparison.is_ne() {
7615                    path_comparison
7616                } else if let Some(snapshot) = snapshot {
7617                    snapshot
7618                        .remote_id()
7619                        .cmp(&cursor_location.buffer_id)
7620                        .then_with(|| {
7621                            anchor
7622                                .text_anchor()
7623                                .cmp(&cursor_location.max_anchor, snapshot)
7624                        })
7625                } else {
7626                    // shouldn't happen because we expect this buffer not to have any excerpts
7627                    // (otherwise snapshot would have been Some)
7628                    Ordering::Equal
7629                }
7630            }
7631        }
7632    }
7633}
7634
7635impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7636    fn cmp(
7637        &self,
7638        cursor_location: &ExcerptSummary,
7639        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7640    ) -> cmp::Ordering {
7641        todo!()
7642    }
7643}
7644
7645impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7646where
7647    MBD: MultiBufferDimension + Default,
7648{
7649    fn zero(_: ()) -> Self {
7650        ExcerptDimension(MBD::default())
7651    }
7652
7653    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7654        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7655    }
7656}
7657
7658#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7659struct OutputDimension<T>(T);
7660
7661impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7662    fn eq(&self, other: &T) -> bool {
7663        self.0 == *other
7664    }
7665}
7666
7667impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7668    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7669        self.0.partial_cmp(other)
7670    }
7671}
7672
7673impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7674where
7675    T: ops::Sub<U, Output = R>,
7676{
7677    type Output = R;
7678
7679    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7680        self.0 - other.0
7681    }
7682}
7683
7684impl<R, T, U> ops::Add<U> for OutputDimension<T>
7685where
7686    T: ops::Add<U, Output = R>,
7687{
7688    type Output = OutputDimension<R>;
7689
7690    fn add(self, other: U) -> Self::Output {
7691        OutputDimension(self.0 + other)
7692    }
7693}
7694
7695impl<T, U> AddAssign<U> for OutputDimension<T>
7696where
7697    T: AddAssign<U>,
7698{
7699    fn add_assign(&mut self, other: U) {
7700        self.0 += other;
7701    }
7702}
7703
7704impl<T, U> SubAssign<U> for OutputDimension<T>
7705where
7706    T: SubAssign<U>,
7707{
7708    fn sub_assign(&mut self, other: U) {
7709        self.0 -= other;
7710    }
7711}
7712
7713#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7714struct ExcerptDimension<T>(T);
7715
7716impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7717    fn eq(&self, other: &T) -> bool {
7718        self.0 == *other
7719    }
7720}
7721
7722impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7723    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7724        self.0.partial_cmp(other)
7725    }
7726}
7727
7728impl ExcerptOffset {
7729    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7730        self.0.saturating_sub(other.0)
7731    }
7732}
7733
7734impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7735where
7736    T: ops::Sub<U, Output = R>,
7737{
7738    type Output = R;
7739
7740    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7741        self.0 - other.0
7742    }
7743}
7744
7745impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7746where
7747    T: ops::Add<U, Output = R>,
7748{
7749    type Output = ExcerptDimension<R>;
7750
7751    fn add(self, other: U) -> Self::Output {
7752        ExcerptDimension(self.0 + other)
7753    }
7754}
7755
7756impl<T, U> AddAssign<U> for ExcerptDimension<T>
7757where
7758    T: AddAssign<U>,
7759{
7760    fn add_assign(&mut self, other: U) {
7761        self.0 += other;
7762    }
7763}
7764
7765impl<T, U> SubAssign<U> for ExcerptDimension<T>
7766where
7767    T: SubAssign<U>,
7768{
7769    fn sub_assign(&mut self, other: U) {
7770        self.0 -= other;
7771    }
7772}
7773
7774impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7775    fn zero(_: ()) -> Self {
7776        MultiBufferOffset::ZERO
7777    }
7778
7779    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7780        *self += summary.output.len;
7781    }
7782}
7783
7784impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7785    for ExcerptDimension<MBD>
7786where
7787    MBD: MultiBufferDimension + Ord,
7788{
7789    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7790        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7791    }
7792}
7793
7794impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7795    for ExcerptDimension<MBD>
7796where
7797    MBD: MultiBufferDimension + Ord,
7798{
7799    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7800        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7801    }
7802}
7803
7804impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7805    for ExcerptDimension<MBD>
7806{
7807    fn zero(_: ()) -> Self {
7808        ExcerptDimension(MBD::default())
7809    }
7810
7811    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7812        self.0.add_mb_text_summary(&summary.input)
7813    }
7814}
7815
7816impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7817    for OutputDimension<MBD>
7818where
7819    MBD: MultiBufferDimension + Ord,
7820{
7821    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7822        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7823    }
7824}
7825
7826impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7827    for OutputDimension<MBD>
7828{
7829    fn zero(_: ()) -> Self {
7830        OutputDimension(MBD::default())
7831    }
7832
7833    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7834        self.0.add_mb_text_summary(&summary.output)
7835    }
7836}
7837
7838impl MultiBufferRows<'_> {
7839    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7840        self.point = Point::new(row, 0);
7841        self.cursor.seek(&self.point);
7842    }
7843}
7844
7845impl Iterator for MultiBufferRows<'_> {
7846    type Item = RowInfo;
7847
7848    fn next(&mut self) -> Option<Self::Item> {
7849        if self.is_empty && self.point.row == 0 {
7850            self.point += Point::new(1, 0);
7851            return Some(RowInfo {
7852                buffer_id: None,
7853                buffer_row: Some(0),
7854                multibuffer_row: Some(MultiBufferRow(0)),
7855                diff_status: None,
7856                expand_info: None,
7857                wrapped_buffer_row: None,
7858            });
7859        }
7860
7861        let mut region = self.cursor.region()?.clone();
7862        while self.point >= region.range.end {
7863            self.cursor.next();
7864            if let Some(next_region) = self.cursor.region() {
7865                region = next_region.clone();
7866            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7867                let multibuffer_row = MultiBufferRow(self.point.row);
7868                let last_excerpt = self
7869                    .cursor
7870                    .excerpts
7871                    .item()
7872                    .or(self.cursor.excerpts.prev_item())?;
7873                let last_row = last_excerpt
7874                    .range
7875                    .context
7876                    .end
7877                    .to_point(&last_excerpt.buffer)
7878                    .row;
7879
7880                let first_row = last_excerpt
7881                    .range
7882                    .context
7883                    .start
7884                    .to_point(&last_excerpt.buffer)
7885                    .row;
7886
7887                let expand_info = if self.is_singleton {
7888                    None
7889                } else {
7890                    let needs_expand_up = first_row == last_row
7891                        && last_row > 0
7892                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7893                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7894
7895                    if needs_expand_up && needs_expand_down {
7896                        Some(ExpandExcerptDirection::UpAndDown)
7897                    } else if needs_expand_up {
7898                        Some(ExpandExcerptDirection::Up)
7899                    } else if needs_expand_down {
7900                        Some(ExpandExcerptDirection::Down)
7901                    } else {
7902                        None
7903                    }
7904                    .map(|direction| ExpandInfo {
7905                        direction,
7906                        excerpt_id: last_excerpt.id,
7907                    })
7908                };
7909                self.point += Point::new(1, 0);
7910                return Some(RowInfo {
7911                    buffer_id: Some(last_excerpt.buffer_id),
7912                    buffer_row: Some(last_row),
7913                    multibuffer_row: Some(multibuffer_row),
7914                    diff_status: None,
7915                    wrapped_buffer_row: None,
7916                    expand_info,
7917                });
7918            } else {
7919                return None;
7920            };
7921        }
7922
7923        let overshoot = self.point - region.range.start;
7924        let buffer_point = region.buffer_range.start + overshoot;
7925        let expand_info = if self.is_singleton {
7926            None
7927        } else {
7928            let needs_expand_up = self.point.row == region.range.start.row
7929                && self.cursor.is_at_start_of_excerpt()
7930                && buffer_point.row > 0;
7931            let needs_expand_down = (region.excerpt.has_trailing_newline
7932                && self.point.row + 1 == region.range.end.row
7933                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7934                && self.cursor.is_at_end_of_excerpt()
7935                && buffer_point.row < region.buffer.max_point().row;
7936
7937            if needs_expand_up && needs_expand_down {
7938                Some(ExpandExcerptDirection::UpAndDown)
7939            } else if needs_expand_up {
7940                Some(ExpandExcerptDirection::Up)
7941            } else if needs_expand_down {
7942                Some(ExpandExcerptDirection::Down)
7943            } else {
7944                None
7945            }
7946            .map(|direction| ExpandInfo {
7947                direction,
7948                excerpt_id: region.excerpt.id,
7949            })
7950        };
7951
7952        let result = Some(RowInfo {
7953            buffer_id: Some(region.buffer.remote_id()),
7954            buffer_row: Some(buffer_point.row),
7955            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7956            diff_status: region
7957                .diff_hunk_status
7958                .filter(|_| self.point < region.range.end),
7959            expand_info,
7960            wrapped_buffer_row: None,
7961        });
7962        self.point += Point::new(1, 0);
7963        result
7964    }
7965}
7966
7967impl<'a> MultiBufferChunks<'a> {
7968    pub fn offset(&self) -> MultiBufferOffset {
7969        self.range.start
7970    }
7971
7972    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7973        self.diff_transforms.seek(&range.end, Bias::Right);
7974        let mut excerpt_end = self.diff_transforms.start().1;
7975        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7976            let overshoot = range.end - self.diff_transforms.start().0;
7977            excerpt_end += overshoot;
7978        }
7979
7980        self.diff_transforms.seek(&range.start, Bias::Right);
7981        let mut excerpt_start = self.diff_transforms.start().1;
7982        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7983            let overshoot = range.start - self.diff_transforms.start().0;
7984            excerpt_start += overshoot;
7985        }
7986
7987        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7988        self.buffer_chunk.take();
7989        self.range = range;
7990    }
7991
7992    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7993        self.excerpt_offset_range = new_range.clone();
7994        self.excerpts.seek(&new_range.start, Bias::Right);
7995        if let Some(excerpt) = self.excerpts.item() {
7996            let excerpt_start = *self.excerpts.start();
7997            if let Some(excerpt_chunks) = self
7998                .excerpt_chunks
7999                .as_mut()
8000                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8001            {
8002                excerpt.seek_chunks(
8003                    excerpt_chunks,
8004                    (self.excerpt_offset_range.start - excerpt_start)
8005                        ..(self.excerpt_offset_range.end - excerpt_start),
8006                );
8007            } else {
8008                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8009                    (self.excerpt_offset_range.start - excerpt_start)
8010                        ..(self.excerpt_offset_range.end - excerpt_start),
8011                    self.language_aware,
8012                ));
8013            }
8014        } else {
8015            self.excerpt_chunks = None;
8016        }
8017    }
8018
8019    #[ztracing::instrument(skip_all)]
8020    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8021        loop {
8022            if self.excerpt_offset_range.is_empty() {
8023                return None;
8024            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8025                self.excerpt_offset_range.start += chunk.text.len();
8026                return Some(chunk);
8027            } else {
8028                self.excerpts.next();
8029                let excerpt = self.excerpts.item()?;
8030                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8031                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8032                    self.language_aware,
8033                ));
8034            }
8035        }
8036    }
8037}
8038
8039impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8040    type Item = &'a str;
8041
8042    fn next(&mut self) -> Option<Self::Item> {
8043        let mut region = self.cursor.region()?;
8044        if self.offset == region.range.start {
8045            self.cursor.prev();
8046            region = self.cursor.region()?;
8047            let start_overshoot = self.start.saturating_sub(region.range.start);
8048            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8049                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8050            ));
8051        }
8052
8053        if self.offset == region.range.end && region.has_trailing_newline {
8054            self.offset -= 1;
8055            Some("\n")
8056        } else {
8057            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8058            self.offset -= chunk.len();
8059            Some(chunk)
8060        }
8061    }
8062}
8063
8064impl<'a> Iterator for MultiBufferChunks<'a> {
8065    type Item = Chunk<'a>;
8066
8067    #[ztracing::instrument(skip_all)]
8068    fn next(&mut self) -> Option<Chunk<'a>> {
8069        if self.range.start >= self.range.end {
8070            return None;
8071        }
8072        if self.range.start == self.diff_transforms.end().0 {
8073            self.diff_transforms.next();
8074        }
8075
8076        let diff_transform_start = self.diff_transforms.start().0;
8077        let diff_transform_end = self.diff_transforms.end().0;
8078        debug_assert!(
8079            self.range.start < diff_transform_end,
8080            "{:?} < {:?} of ({1:?}..{2:?})",
8081            self.range.start,
8082            diff_transform_end,
8083            diff_transform_start
8084        );
8085
8086        let diff_transform = self.diff_transforms.item()?;
8087        match diff_transform {
8088            DiffTransform::BufferContent { .. } => {
8089                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8090                    chunk
8091                } else {
8092                    let chunk = self.next_excerpt_chunk().unwrap();
8093                    self.buffer_chunk.insert(chunk)
8094                };
8095
8096                let chunk_end = self.range.start + chunk.text.len();
8097                let diff_transform_end = diff_transform_end.min(self.range.end);
8098
8099                if diff_transform_end < chunk_end {
8100                    let split_idx = diff_transform_end - self.range.start;
8101                    let (before, after) = chunk.text.split_at(split_idx);
8102                    self.range.start = diff_transform_end;
8103                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8104                    let chars = chunk.chars & mask;
8105                    let tabs = chunk.tabs & mask;
8106                    let newlines = chunk.newlines & mask;
8107
8108                    chunk.text = after;
8109                    chunk.chars = chunk.chars >> split_idx;
8110                    chunk.tabs = chunk.tabs >> split_idx;
8111                    chunk.newlines = chunk.newlines >> split_idx;
8112
8113                    Some(Chunk {
8114                        text: before,
8115                        chars,
8116                        tabs,
8117                        newlines,
8118                        ..chunk.clone()
8119                    })
8120                } else {
8121                    self.range.start = chunk_end;
8122                    self.buffer_chunk.take()
8123                }
8124            }
8125            DiffTransform::DeletedHunk {
8126                buffer_id,
8127                base_text_byte_range,
8128                has_trailing_newline,
8129                ..
8130            } => {
8131                let base_text_start =
8132                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8133                let base_text_end =
8134                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8135                let base_text_end = base_text_end.min(base_text_byte_range.end);
8136
8137                let mut chunks = if let Some((_, mut chunks)) = self
8138                    .diff_base_chunks
8139                    .take()
8140                    .filter(|(id, _)| id == buffer_id)
8141                {
8142                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8143                    {
8144                        chunks.seek(base_text_start..base_text_end);
8145                    }
8146                    chunks
8147                } else {
8148                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8149                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8150                };
8151
8152                let chunk = if let Some(chunk) = chunks.next() {
8153                    self.range.start += chunk.text.len();
8154                    self.diff_base_chunks = Some((*buffer_id, chunks));
8155                    chunk
8156                } else {
8157                    debug_assert!(has_trailing_newline);
8158                    self.range.start += "\n".len();
8159                    Chunk {
8160                        text: "\n",
8161                        chars: 1u128,
8162                        newlines: 1u128,
8163                        ..Default::default()
8164                    }
8165                };
8166                Some(chunk)
8167            }
8168        }
8169    }
8170}
8171
8172impl MultiBufferBytes<'_> {
8173    fn consume(&mut self, len: usize) {
8174        self.range.start += len;
8175        self.chunk = &self.chunk[len..];
8176
8177        if !self.range.is_empty() && self.chunk.is_empty() {
8178            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8179                self.chunk = chunk;
8180            } else if self.has_trailing_newline {
8181                self.has_trailing_newline = false;
8182                self.chunk = b"\n";
8183            } else {
8184                self.cursor.next();
8185                if let Some(region) = self.cursor.region() {
8186                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8187                        region.buffer_range.start
8188                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8189                                .min(region.buffer_range.end),
8190                    );
8191                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8192                    self.excerpt_bytes = Some(excerpt_bytes);
8193                    self.has_trailing_newline =
8194                        region.has_trailing_newline && self.range.end >= region.range.end;
8195                    if self.chunk.is_empty() && self.has_trailing_newline {
8196                        self.has_trailing_newline = false;
8197                        self.chunk = b"\n";
8198                    }
8199                }
8200            }
8201        }
8202    }
8203}
8204
8205impl<'a> Iterator for MultiBufferBytes<'a> {
8206    type Item = &'a [u8];
8207
8208    fn next(&mut self) -> Option<Self::Item> {
8209        let chunk = self.chunk;
8210        if chunk.is_empty() {
8211            None
8212        } else {
8213            self.consume(chunk.len());
8214            Some(chunk)
8215        }
8216    }
8217}
8218
8219impl io::Read for MultiBufferBytes<'_> {
8220    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8221        let len = cmp::min(buf.len(), self.chunk.len());
8222        buf[..len].copy_from_slice(&self.chunk[..len]);
8223        if len > 0 {
8224            self.consume(len);
8225        }
8226        Ok(len)
8227    }
8228}
8229
8230impl io::Read for ReversedMultiBufferBytes<'_> {
8231    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8232        let len = cmp::min(buf.len(), self.chunk.len());
8233        buf[..len].copy_from_slice(&self.chunk[..len]);
8234        buf[..len].reverse();
8235        if len > 0 {
8236            self.range.end -= len;
8237            self.chunk = &self.chunk[..self.chunk.len() - len];
8238            if !self.range.is_empty()
8239                && self.chunk.is_empty()
8240                && let Some(chunk) = self.chunks.next()
8241            {
8242                self.chunk = chunk.as_bytes();
8243            }
8244        }
8245        Ok(len)
8246    }
8247}
8248
8249impl<'a> Iterator for ExcerptChunks<'a> {
8250    type Item = Chunk<'a>;
8251
8252    fn next(&mut self) -> Option<Self::Item> {
8253        if let Some(chunk) = self.content_chunks.next() {
8254            return Some(chunk);
8255        }
8256
8257        if self.has_footer {
8258            let text = "\n";
8259            let chars = 0b1;
8260            let newlines = 0b1;
8261            self.has_footer = false;
8262            return Some(Chunk {
8263                text,
8264                chars,
8265                newlines,
8266                ..Default::default()
8267            });
8268        }
8269
8270        None
8271    }
8272}
8273
8274impl ToOffset for Point {
8275    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8276        snapshot.point_to_offset(*self)
8277    }
8278    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8279        snapshot.point_to_offset_utf16(*self)
8280    }
8281}
8282
8283impl ToOffset for MultiBufferOffset {
8284    #[track_caller]
8285    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8286        assert!(
8287            *self <= snapshot.len(),
8288            "offset {} is greater than the snapshot.len() {}",
8289            self.0,
8290            snapshot.len().0,
8291        );
8292        *self
8293    }
8294    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8295        snapshot.offset_to_offset_utf16(*self)
8296    }
8297}
8298
8299impl ToOffset for MultiBufferOffsetUtf16 {
8300    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8301        snapshot.offset_utf16_to_offset(*self)
8302    }
8303
8304    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8305        *self
8306    }
8307}
8308
8309impl ToOffset for PointUtf16 {
8310    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8311        snapshot.point_utf16_to_offset(*self)
8312    }
8313    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8314        snapshot.point_utf16_to_offset_utf16(*self)
8315    }
8316}
8317
8318impl ToPoint for MultiBufferOffset {
8319    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8320        snapshot.offset_to_point(*self)
8321    }
8322    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8323        snapshot.offset_to_point_utf16(*self)
8324    }
8325}
8326
8327impl ToPoint for Point {
8328    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8329        *self
8330    }
8331    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8332        snapshot.point_to_point_utf16(*self)
8333    }
8334}
8335
8336impl ToPoint for PointUtf16 {
8337    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8338        snapshot.point_utf16_to_point(*self)
8339    }
8340    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8341        *self
8342    }
8343}
8344
8345#[cfg(debug_assertions)]
8346pub mod debug {
8347    use super::*;
8348
8349    pub trait ToMultiBufferDebugRanges {
8350        fn to_multi_buffer_debug_ranges(
8351            &self,
8352            snapshot: &MultiBufferSnapshot,
8353        ) -> Vec<Range<MultiBufferOffset>>;
8354    }
8355
8356    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8357        fn to_multi_buffer_debug_ranges(
8358            &self,
8359            snapshot: &MultiBufferSnapshot,
8360        ) -> Vec<Range<MultiBufferOffset>> {
8361            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8362        }
8363    }
8364
8365    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8366        fn to_multi_buffer_debug_ranges(
8367            &self,
8368            snapshot: &MultiBufferSnapshot,
8369        ) -> Vec<Range<MultiBufferOffset>> {
8370            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8371                .to_multi_buffer_debug_ranges(snapshot)
8372        }
8373    }
8374
8375    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8376        fn to_multi_buffer_debug_ranges(
8377            &self,
8378            snapshot: &MultiBufferSnapshot,
8379        ) -> Vec<Range<MultiBufferOffset>> {
8380            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8381        }
8382    }
8383
8384    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8385        fn to_multi_buffer_debug_ranges(
8386            &self,
8387            snapshot: &MultiBufferSnapshot,
8388        ) -> Vec<Range<MultiBufferOffset>> {
8389            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8390        }
8391    }
8392
8393    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8394        fn to_multi_buffer_debug_ranges(
8395            &self,
8396            snapshot: &MultiBufferSnapshot,
8397        ) -> Vec<Range<MultiBufferOffset>> {
8398            self.iter()
8399                .map(|item| {
8400                    let offset = item.to_offset(snapshot);
8401                    offset..offset
8402                })
8403                .collect()
8404        }
8405    }
8406
8407    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8408        fn to_multi_buffer_debug_ranges(
8409            &self,
8410            snapshot: &MultiBufferSnapshot,
8411        ) -> Vec<Range<MultiBufferOffset>> {
8412            self.iter()
8413                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8414                .collect()
8415        }
8416    }
8417}