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 start = selection.start.seek_target(&snapshot);
1638
1639            cursor.seek(&start, Bias::Left);
1640            while let Some(excerpt) = cursor.item() {
1641                // todo!() method?
1642                let excerpt_start =
1643                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.end);
1644                if excerpt_start.cmp(&selection.end, &snapshot).is_gt() {
1645                    break;
1646                }
1647                let start = text::Anchor::max(
1648                    &excerpt.range.context.start,
1649                    &selection.start.text_anchor().unwrap_or(text::Anchor::MIN),
1650                    &excerpt.buffer,
1651                )
1652                .clone();
1653                let end = text::Anchor::min(
1654                    &excerpt.range.context.end,
1655                    &selection.end.text_anchor().unwrap_or(text::Anchor::MAX),
1656                    &excerpt.buffer,
1657                )
1658                .clone();
1659                selections_by_buffer
1660                    .entry(excerpt.buffer.remote_id())
1661                    .or_default()
1662                    .push(Selection {
1663                        id: selection.id,
1664                        start,
1665                        end,
1666                        reversed: selection.reversed,
1667                        goal: selection.goal,
1668                    });
1669
1670                cursor.next();
1671            }
1672        }
1673
1674        for (buffer_id, buffer_state) in self.buffers.iter() {
1675            if !selections_by_buffer.contains_key(buffer_id) {
1676                buffer_state
1677                    .buffer
1678                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1679            }
1680        }
1681
1682        for (buffer_id, selections) in selections_by_buffer {
1683            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1684                buffer.set_active_selections(selections.into(), line_mode, cursor_shape, cx);
1685            });
1686        }
1687    }
1688
1689    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1690        for buffer in self.buffers.values() {
1691            buffer
1692                .buffer
1693                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1694        }
1695    }
1696
1697    #[instrument(skip_all)]
1698    fn merge_excerpt_ranges<'a>(
1699        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1700    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1701        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1702        let mut counts: Vec<usize> = Vec::new();
1703        for range in expanded_ranges {
1704            if let Some(last_range) = merged_ranges.last_mut() {
1705                assert!(
1706                    last_range.context.start <= range.context.start,
1707                    "ranges must be sorted: {last_range:?} <= {range:?}"
1708                );
1709                if last_range.context.end >= range.context.start
1710                    || last_range.context.end.row + 1 == range.context.start.row
1711                {
1712                    last_range.context.end = range.context.end.max(last_range.context.end);
1713                    *counts.last_mut().unwrap() += 1;
1714                    continue;
1715                }
1716            }
1717            merged_ranges.push(range.clone());
1718            counts.push(1);
1719        }
1720        (merged_ranges, counts)
1721    }
1722
1723    pub fn clear(&mut self, cx: &mut Context<Self>) {
1724        self.sync_mut(cx);
1725        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1726        let MultiBufferSnapshot {
1727            excerpts,
1728            diffs: _,
1729            diff_transforms: _,
1730            non_text_state_update_count: _,
1731            edit_count: _,
1732            is_dirty,
1733            has_deleted_file,
1734            has_conflict,
1735            has_inverted_diff,
1736            singleton: _,
1737            trailing_excerpt_update_count,
1738            all_diff_hunks_expanded: _,
1739            show_deleted_hunks: _,
1740            use_extended_diff_range: _,
1741            show_headers: _,
1742            path_keys_by_buffer: _,
1743            path_keys_by_index: _,
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(excerpt_anchor) = anchor.excerpt_anchor() {
1941                if let Some(buffer) = self.buffers.get(&excerpt_anchor.buffer_id) {
1942                    buffer.buffer.update(cx, |buffer, _| {
1943                        futures.push(buffer.wait_for_anchors([excerpt_anchor.text_anchor()]))
1944                    });
1945                } else {
1946                    error = Some(anyhow!(
1947                        "buffer {:?} is not part of this multi-buffer",
1948                        excerpt_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).excerpt_anchor()?;
1972        let buffer = self.buffers.get(&anchor.buffer_id)?.buffer.clone();
1973        Some((buffer, anchor.text_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        let Some(buffer) = self.buffer(diff.read(cx).buffer_id) else {
2041            return;
2042        };
2043        let snapshot = self.sync_mut(cx);
2044
2045        let diff = diff.read(cx);
2046        let buffer_id = diff.buffer_id;
2047
2048        let Some(path) = snapshot.path_for_buffer(buffer_id).cloned() else {
2049            return;
2050        };
2051        let new_diff = DiffStateSnapshot {
2052            diff: diff.snapshot(cx),
2053            main_buffer: None,
2054        };
2055        let base_text_changed = snapshot
2056            .diffs
2057            .get(&buffer_id)
2058            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2059        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2060
2061        let buffer = buffer.read(cx);
2062        let diff_change_range = range.to_offset(buffer);
2063
2064        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2065        let edits = Self::sync_diff_transforms(
2066            snapshot,
2067            excerpt_edits,
2068            DiffChangeKind::DiffUpdated {
2069                base_changed: base_text_changed,
2070            },
2071        );
2072        if !edits.is_empty() {
2073            self.subscriptions.publish(edits);
2074        }
2075        cx.emit(Event::Edited {
2076            edited_buffer: None,
2077        });
2078    }
2079
2080    fn inverted_buffer_diff_changed(
2081        &mut self,
2082        diff: Entity<BufferDiff>,
2083        main_buffer: Entity<language::Buffer>,
2084        diff_change_range: Option<Range<usize>>,
2085        cx: &mut Context<Self>,
2086    ) {
2087        let snapshot = self.sync_mut(cx);
2088
2089        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2090        let Some(path) = snapshot.path_for_buffer(base_text_buffer_id).cloned() else {
2091            return;
2092        };
2093
2094        let main_buffer_snapshot = main_buffer.read(cx).snapshot();
2095        let diff = diff.read(cx);
2096        let new_diff = DiffStateSnapshot {
2097            diff: diff.snapshot(cx),
2098            main_buffer: Some(main_buffer_snapshot),
2099        };
2100        snapshot
2101            .diffs
2102            .insert_or_replace(base_text_buffer_id, new_diff);
2103
2104        let Some(diff_change_range) = diff_change_range else {
2105            return;
2106        };
2107
2108        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(&path, diff_change_range);
2109        let edits = Self::sync_diff_transforms(
2110            snapshot,
2111            excerpt_edits,
2112            DiffChangeKind::DiffUpdated {
2113                // We don't read this field for inverted diffs.
2114                base_changed: false,
2115            },
2116        );
2117        if !edits.is_empty() {
2118            self.subscriptions.publish(edits);
2119        }
2120        cx.emit(Event::Edited {
2121            edited_buffer: None,
2122        });
2123    }
2124
2125    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2126        self.buffers.values().map(|state| state.buffer.clone())
2127    }
2128
2129    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2130        self.all_buffers_iter().collect()
2131    }
2132
2133    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2134        self.buffers.keys().copied()
2135    }
2136
2137    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2138        self.all_buffer_ids_iter().collect()
2139    }
2140
2141    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2142        self.buffers
2143            .get(&buffer_id)
2144            .map(|state| state.buffer.clone())
2145    }
2146
2147    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2148        self.point_to_buffer_offset(point, cx)
2149            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2150    }
2151
2152    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2153        let buffer_id = self
2154            .snapshot
2155            .borrow()
2156            .excerpts
2157            .first()
2158            .map(|excerpt| excerpt.buffer.remote_id());
2159        buffer_id
2160            .and_then(|buffer_id| self.buffer(buffer_id))
2161            .map(|buffer| {
2162                let buffer = buffer.read(cx);
2163                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2164            })
2165            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2166    }
2167
2168    pub fn language_settings_at<'a, T: ToOffset>(
2169        &'a self,
2170        point: T,
2171        cx: &'a App,
2172    ) -> Cow<'a, LanguageSettings> {
2173        let mut language = None;
2174        let mut file = None;
2175        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2176            let buffer = buffer.read(cx);
2177            language = buffer.language_at(offset);
2178            file = buffer.file();
2179        }
2180        language_settings(language.map(|l| l.name()), file, cx)
2181    }
2182
2183    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2184        self.buffers.values().for_each(|state| f(&state.buffer))
2185    }
2186
2187    pub fn explicit_title(&self) -> Option<&str> {
2188        self.title.as_deref()
2189    }
2190
2191    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2192        if let Some(title) = self.title.as_ref() {
2193            return title.into();
2194        }
2195
2196        if let Some(buffer) = self.as_singleton() {
2197            let buffer = buffer.read(cx);
2198
2199            if let Some(file) = buffer.file() {
2200                return file.file_name(cx).into();
2201            }
2202
2203            if let Some(title) = self.buffer_content_title(buffer) {
2204                return title;
2205            }
2206        };
2207
2208        "untitled".into()
2209    }
2210
2211    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2212        let mut is_leading_whitespace = true;
2213        let mut count = 0;
2214        let mut prev_was_space = false;
2215        let mut title = String::new();
2216
2217        for ch in buffer.snapshot().chars() {
2218            if is_leading_whitespace && ch.is_whitespace() {
2219                continue;
2220            }
2221
2222            is_leading_whitespace = false;
2223
2224            if ch == '\n' || count >= 40 {
2225                break;
2226            }
2227
2228            if ch.is_whitespace() {
2229                if !prev_was_space {
2230                    title.push(' ');
2231                    count += 1;
2232                    prev_was_space = true;
2233                }
2234            } else {
2235                title.push(ch);
2236                count += 1;
2237                prev_was_space = false;
2238            }
2239        }
2240
2241        let title = title.trim_end().to_string();
2242
2243        if title.is_empty() {
2244            return None;
2245        }
2246
2247        Some(title.into())
2248    }
2249
2250    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2251        self.title = Some(title);
2252        cx.notify();
2253    }
2254
2255    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2256    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2257        for buffer_state in self.buffers.values() {
2258            buffer_state
2259                .buffer
2260                .update(cx, |buffer, _cx| buffer.refresh_preview());
2261        }
2262    }
2263
2264    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2265    pub fn preserve_preview(&self, cx: &App) -> bool {
2266        self.buffers
2267            .values()
2268            .all(|state| state.buffer.read(cx).preserve_preview())
2269    }
2270
2271    #[cfg(any(test, feature = "test-support"))]
2272    pub fn is_parsing(&self, cx: &App) -> bool {
2273        self.as_singleton().unwrap().read(cx).is_parsing()
2274    }
2275
2276    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2277        let buffer_id = diff.read(cx).buffer_id;
2278
2279        if let Some(existing_diff) = self.diff_for(buffer_id)
2280            && diff.entity_id() == existing_diff.entity_id()
2281        {
2282            return;
2283        }
2284
2285        self.buffer_diff_changed(
2286            diff.clone(),
2287            text::Anchor::min_max_range_for_buffer(buffer_id),
2288            cx,
2289        );
2290        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2291    }
2292
2293    pub fn add_inverted_diff(
2294        &mut self,
2295        diff: Entity<BufferDiff>,
2296        main_buffer: Entity<language::Buffer>,
2297        cx: &mut Context<Self>,
2298    ) {
2299        let snapshot = diff.read(cx).base_text(cx);
2300        let base_text_buffer_id = snapshot.remote_id();
2301        let diff_change_range = 0..snapshot.len();
2302        self.snapshot.get_mut().has_inverted_diff = true;
2303        self.inverted_buffer_diff_changed(
2304            diff.clone(),
2305            main_buffer.clone(),
2306            Some(diff_change_range),
2307            cx,
2308        );
2309        self.diffs.insert(
2310            base_text_buffer_id,
2311            DiffState::new_inverted(diff, main_buffer, cx),
2312        );
2313    }
2314
2315    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2316        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2317    }
2318
2319    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2320        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2321    }
2322
2323    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2324        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2325    }
2326
2327    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2328        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2329        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2330    }
2331
2332    pub fn all_diff_hunks_expanded(&self) -> bool {
2333        self.snapshot.borrow().all_diff_hunks_expanded
2334    }
2335
2336    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2337        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2338        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2339    }
2340
2341    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2342        self.snapshot.get_mut().show_deleted_hunks = show;
2343
2344        self.sync_mut(cx);
2345
2346        let old_len = self.snapshot.borrow().len();
2347
2348        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2349        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2350
2351        let new_len = self.snapshot.borrow().len();
2352
2353        self.subscriptions.publish(vec![Edit {
2354            old: MultiBufferOffset(0)..old_len,
2355            new: MultiBufferOffset(0)..new_len,
2356        }]);
2357
2358        cx.emit(Event::DiffHunksToggled);
2359        cx.emit(Event::Edited {
2360            edited_buffer: None,
2361        });
2362    }
2363
2364    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2365        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2366    }
2367
2368    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2369        self.read(cx)
2370            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2371            .nth(1)
2372            .is_some()
2373    }
2374
2375    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2376        let snapshot = self.read(cx);
2377        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2378        let offset_range = range.to_offset(&snapshot);
2379        cursor.seek(&offset_range.start, Bias::Left);
2380        while let Some(item) = cursor.item() {
2381            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2382                break;
2383            }
2384            if item.hunk_info().is_some() {
2385                return true;
2386            }
2387            cursor.next();
2388        }
2389        false
2390    }
2391
2392    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2393        let snapshot = self.read(cx);
2394        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2395        for range in ranges {
2396            let range = range.to_point(&snapshot);
2397            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2398            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2399                .min(snapshot.len());
2400            cursor.seek(&start, Bias::Right);
2401            while let Some(item) = cursor.item() {
2402                if *cursor.start() >= end {
2403                    break;
2404                }
2405                if item.hunk_info().is_some() {
2406                    return true;
2407                }
2408                cursor.next();
2409            }
2410        }
2411        false
2412    }
2413
2414    pub fn expand_or_collapse_diff_hunks_inner(
2415        &mut self,
2416        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2417        expand: bool,
2418        cx: &mut Context<Self>,
2419    ) -> Vec<Edit<MultiBufferOffset>> {
2420        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2421            return Vec::new();
2422        }
2423        self.sync_mut(cx);
2424        let mut snapshot = self.snapshot.get_mut();
2425        let mut excerpt_edits = Vec::new();
2426        let mut last_hunk_row = None;
2427        for (range, end_excerpt_id) in ranges {
2428            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2429                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2430                    continue;
2431                }
2432                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2433                    continue;
2434                }
2435                let start = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2436                let end = Anchor::text(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2437                let start = snapshot.excerpt_offset_for_anchor(&start);
2438                let end = snapshot.excerpt_offset_for_anchor(&end);
2439                last_hunk_row = Some(diff_hunk.row_range.start);
2440                excerpt_edits.push(text::Edit {
2441                    old: start..end,
2442                    new: start..end,
2443                });
2444            }
2445        }
2446
2447        Self::sync_diff_transforms(
2448            &mut snapshot,
2449            excerpt_edits,
2450            DiffChangeKind::ExpandOrCollapseHunks { expand },
2451        )
2452    }
2453
2454    pub fn expand_or_collapse_diff_hunks(
2455        &mut self,
2456        ranges: Vec<Range<Anchor>>,
2457        expand: bool,
2458        cx: &mut Context<Self>,
2459    ) {
2460        let snapshot = self.snapshot.borrow().clone();
2461        let ranges = ranges.iter().map(move |range| {
2462            let end_excerpt_id = range.end.excerpt_id;
2463            let range = range.to_point(&snapshot);
2464            let mut peek_end = range.end;
2465            if range.end.row < snapshot.max_row().0 {
2466                peek_end = Point::new(range.end.row + 1, 0);
2467            };
2468            (range.start..peek_end, end_excerpt_id)
2469        });
2470        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2471        if !edits.is_empty() {
2472            self.subscriptions.publish(edits);
2473        }
2474        cx.emit(Event::DiffHunksToggled);
2475        cx.emit(Event::Edited {
2476            edited_buffer: None,
2477        });
2478    }
2479
2480    pub fn resize_excerpt(
2481        &mut self,
2482        id: ExcerptId,
2483        range: Range<text::Anchor>,
2484        cx: &mut Context<Self>,
2485    ) {
2486        self.sync_mut(cx);
2487
2488        let mut snapshot = self.snapshot.get_mut();
2489        let locator = snapshot.excerpt_locator_for_id(id);
2490        let mut new_excerpts = SumTree::default();
2491        let mut cursor = snapshot
2492            .excerpts
2493            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2494        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2495
2496        let prefix = cursor.slice(&Some(locator), Bias::Left);
2497        new_excerpts.append(prefix, ());
2498
2499        let mut excerpt = cursor.item().unwrap().clone();
2500        let old_text_len = excerpt.text_summary.len;
2501
2502        excerpt.range.context.start = range.start;
2503        excerpt.range.context.end = range.end;
2504        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2505
2506        excerpt.text_summary = excerpt
2507            .buffer
2508            .text_summary_for_range(excerpt.range.context.clone());
2509
2510        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2511        let old_start_offset = cursor.start().1;
2512        let new_text_len = excerpt.text_summary.len;
2513        let edit = Edit {
2514            old: old_start_offset..old_start_offset + old_text_len,
2515            new: new_start_offset..new_start_offset + new_text_len,
2516        };
2517
2518        if let Some(last_edit) = edits.last_mut() {
2519            if last_edit.old.end == edit.old.start {
2520                last_edit.old.end = edit.old.end;
2521                last_edit.new.end = edit.new.end;
2522            } else {
2523                edits.push(edit);
2524            }
2525        } else {
2526            edits.push(edit);
2527        }
2528
2529        new_excerpts.push(excerpt, ());
2530
2531        cursor.next();
2532
2533        new_excerpts.append(cursor.suffix(), ());
2534
2535        drop(cursor);
2536        snapshot.excerpts = new_excerpts;
2537
2538        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2539        if !edits.is_empty() {
2540            self.subscriptions.publish(edits);
2541        }
2542        cx.emit(Event::Edited {
2543            edited_buffer: None,
2544        });
2545        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2546        cx.notify();
2547    }
2548
2549    pub fn expand_excerpts(
2550        &mut self,
2551        ids: impl IntoIterator<Item = ExcerptId>,
2552        line_count: u32,
2553        direction: ExpandExcerptDirection,
2554        cx: &mut Context<Self>,
2555    ) {
2556        if line_count == 0 {
2557            return;
2558        }
2559        self.sync_mut(cx);
2560        if !self.excerpts_by_path.is_empty() {
2561            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2562            return;
2563        }
2564        let mut snapshot = self.snapshot.get_mut();
2565
2566        let ids = ids.into_iter().collect::<Vec<_>>();
2567        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2568        let mut new_excerpts = SumTree::default();
2569        let mut cursor = snapshot
2570            .excerpts
2571            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2572        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2573
2574        for locator in &locators {
2575            let prefix = cursor.slice(&Some(locator), Bias::Left);
2576            new_excerpts.append(prefix, ());
2577
2578            let mut excerpt = cursor.item().unwrap().clone();
2579            let old_text_len = excerpt.text_summary.len;
2580
2581            let up_line_count = if direction.should_expand_up() {
2582                line_count
2583            } else {
2584                0
2585            };
2586
2587            let start_row = excerpt
2588                .range
2589                .context
2590                .start
2591                .to_point(&excerpt.buffer)
2592                .row
2593                .saturating_sub(up_line_count);
2594            let start_point = Point::new(start_row, 0);
2595            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2596
2597            let down_line_count = if direction.should_expand_down() {
2598                line_count
2599            } else {
2600                0
2601            };
2602
2603            let mut end_point = excerpt.buffer.clip_point(
2604                excerpt.range.context.end.to_point(&excerpt.buffer)
2605                    + Point::new(down_line_count, 0),
2606                Bias::Left,
2607            );
2608            end_point.column = excerpt.buffer.line_len(end_point.row);
2609            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2610            excerpt.max_buffer_row = end_point.row;
2611
2612            excerpt.text_summary = excerpt
2613                .buffer
2614                .text_summary_for_range(excerpt.range.context.clone());
2615
2616            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2617            let old_start_offset = cursor.start().1;
2618            let new_text_len = excerpt.text_summary.len;
2619            let edit = Edit {
2620                old: old_start_offset..old_start_offset + old_text_len,
2621                new: new_start_offset..new_start_offset + new_text_len,
2622            };
2623
2624            if let Some(last_edit) = edits.last_mut() {
2625                if last_edit.old.end == edit.old.start {
2626                    last_edit.old.end = edit.old.end;
2627                    last_edit.new.end = edit.new.end;
2628                } else {
2629                    edits.push(edit);
2630                }
2631            } else {
2632                edits.push(edit);
2633            }
2634
2635            new_excerpts.push(excerpt, ());
2636
2637            cursor.next();
2638        }
2639
2640        new_excerpts.append(cursor.suffix(), ());
2641
2642        drop(cursor);
2643        snapshot.excerpts = new_excerpts;
2644
2645        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2646        if !edits.is_empty() {
2647            self.subscriptions.publish(edits);
2648        }
2649        cx.emit(Event::Edited {
2650            edited_buffer: None,
2651        });
2652        cx.emit(Event::ExcerptsExpanded { ids });
2653        cx.notify();
2654    }
2655
2656    #[ztracing::instrument(skip_all)]
2657    fn sync(&self, cx: &App) {
2658        let changed = self.buffer_changed_since_sync.replace(false);
2659        if !changed {
2660            return;
2661        }
2662        let edits = Self::sync_from_buffer_changes(
2663            &mut self.snapshot.borrow_mut(),
2664            &self.buffers,
2665            &self.diffs,
2666            cx,
2667        );
2668        if !edits.is_empty() {
2669            self.subscriptions.publish(edits);
2670        }
2671    }
2672
2673    fn sync_mut(&mut self, cx: &App) -> &mut MultiBufferSnapshot {
2674        let snapshot = self.snapshot.get_mut();
2675        let changed = self.buffer_changed_since_sync.replace(false);
2676        if !changed {
2677            return snapshot;
2678        }
2679        let edits = Self::sync_from_buffer_changes(snapshot, &self.buffers, &self.diffs, cx);
2680
2681        if !edits.is_empty() {
2682            self.subscriptions.publish(edits);
2683        }
2684
2685        snapshot
2686    }
2687
2688    fn sync_from_buffer_changes(
2689        snapshot: &mut MultiBufferSnapshot,
2690        buffers: &BTreeMap<BufferId, BufferState>,
2691        diffs: &HashMap<BufferId, DiffState>,
2692        cx: &App,
2693    ) -> Vec<Edit<MultiBufferOffset>> {
2694        let MultiBufferSnapshot {
2695            excerpts,
2696            diffs: buffer_diff,
2697            path_keys_by_buffer,
2698            path_keys_by_index,
2699            diff_transforms: _,
2700            non_text_state_update_count,
2701            edit_count,
2702            is_dirty,
2703            has_deleted_file,
2704            has_conflict,
2705            has_inverted_diff: _,
2706            singleton: _,
2707            trailing_excerpt_update_count: _,
2708            all_diff_hunks_expanded: _,
2709            show_deleted_hunks: _,
2710            use_extended_diff_range: _,
2711            show_headers: _,
2712        } = snapshot;
2713        *is_dirty = false;
2714        *has_deleted_file = false;
2715        *has_conflict = false;
2716
2717        if !diffs.is_empty() {
2718            let mut diffs_to_add = Vec::new();
2719            for (id, diff) in diffs {
2720                // For inverted diffs, we excerpt the diff base texts in the multibuffer
2721                // and use the diff hunk base text ranges to compute diff transforms.
2722                // Those base text ranges are usize, so make sure if the base text changed
2723                // we also update the diff snapshot so that we don't use stale offsets
2724                if buffer_diff.get(id).is_none_or(|existing_diff| {
2725                    if existing_diff.main_buffer.is_none() {
2726                        return false;
2727                    }
2728                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
2729                    base_text.remote_id() != existing_diff.base_text().remote_id()
2730                        || base_text
2731                            .version()
2732                            .changed_since(existing_diff.base_text().version())
2733                }) {
2734                    if diffs_to_add.capacity() == 0 {
2735                        // we'd rather overallocate than reallocate as buffer diffs are quite big
2736                        // meaning re-allocations will be fairly expensive
2737                        diffs_to_add.reserve(diffs.len());
2738                    }
2739                    diffs_to_add.push((*id, diff.snapshot(cx)));
2740                }
2741            }
2742            buffer_diff.extend(diffs_to_add);
2743        }
2744
2745        let mut paths_to_edit = Vec::new();
2746        let mut non_text_state_updated = false;
2747        let mut edited = false;
2748        for buffer_state in buffers.values() {
2749            let buffer = buffer_state.buffer.read(cx);
2750            let version = buffer.version();
2751            let non_text_state_update_count = buffer.non_text_state_update_count();
2752
2753            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2754            let buffer_non_text_state_updated =
2755                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2756            if (buffer_edited || buffer_non_text_state_updated)
2757                && let Some(path_key) = path_keys_by_buffer.get(&buffer.remote_id())
2758            {
2759                *buffer_state.last_version.borrow_mut() = version;
2760                buffer_state
2761                    .last_non_text_state_update_count
2762                    .set(non_text_state_update_count);
2763                paths_to_edit.push((path_key.clone(), buffer_state.buffer.clone(), buffer_edited));
2764            }
2765
2766            edited |= buffer_edited;
2767            non_text_state_updated |= buffer_non_text_state_updated;
2768            *is_dirty |= buffer.is_dirty();
2769            *has_deleted_file |= buffer
2770                .file()
2771                .is_some_and(|file| file.disk_state().is_deleted());
2772            *has_conflict |= buffer.has_conflict();
2773        }
2774        if edited {
2775            *edit_count += 1;
2776        }
2777        if non_text_state_updated {
2778            *non_text_state_update_count += 1;
2779        }
2780
2781        paths_to_edit.sort_unstable_by_key(|(path, _, _)| path);
2782
2783        let mut edits = Vec::new();
2784        let mut new_excerpts = SumTree::default();
2785        let mut cursor = excerpts.cursor::<ExcerptSummary>(());
2786
2787        for (path, buffer, buffer_edited) in paths_to_edit {
2788            new_excerpts.append(cursor.slice(&path, Bias::Left), ());
2789            let old_excerpt = cursor.item().unwrap();
2790            let buffer = buffer.read(cx);
2791            let buffer_id = buffer.remote_id();
2792            let mut new_excerpt;
2793            if buffer_edited {
2794                edits.extend(
2795                    buffer
2796                        .edits_since_in_range::<usize>(
2797                            old_excerpt.buffer.version(),
2798                            old_excerpt.range.context.clone(),
2799                        )
2800                        .map(|edit| {
2801                            let excerpt_old_start = cursor.start().1;
2802                            let excerpt_new_start =
2803                                ExcerptDimension(new_excerpts.summary().text.len);
2804                            let old_start = excerpt_old_start + edit.old.start;
2805                            let old_end = excerpt_old_start + edit.old.end;
2806                            let new_start = excerpt_new_start + edit.new.start;
2807                            let new_end = excerpt_new_start + edit.new.end;
2808                            Edit {
2809                                old: old_start..old_end,
2810                                new: new_start..new_end,
2811                            }
2812                        }),
2813                );
2814
2815                new_excerpt = Excerpt::new(
2816                    path,
2817                    Arc::new(buffer.snapshot()),
2818                    old_excerpt.range.clone(),
2819                    old_excerpt.has_trailing_newline,
2820                );
2821            } else {
2822                new_excerpt = old_excerpt.clone();
2823                new_excerpt.buffer = Arc::new(buffer.snapshot());
2824            }
2825
2826            new_excerpts.push(new_excerpt, ());
2827            cursor.next();
2828        }
2829        new_excerpts.append(cursor.suffix(), ());
2830
2831        drop(cursor);
2832        *excerpts = new_excerpts;
2833
2834        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2835    }
2836
2837    fn sync_diff_transforms(
2838        snapshot: &mut MultiBufferSnapshot,
2839        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2840        change_kind: DiffChangeKind,
2841    ) -> Vec<Edit<MultiBufferOffset>> {
2842        if excerpt_edits.is_empty() {
2843            return vec![];
2844        }
2845
2846        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2847        let mut old_diff_transforms = snapshot
2848            .diff_transforms
2849            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2850        let mut new_diff_transforms = SumTree::default();
2851        let mut old_expanded_hunks = HashSet::default();
2852        let mut output_edits = Vec::new();
2853        let mut output_delta = 0_isize;
2854        let mut at_transform_boundary = true;
2855        let mut end_of_current_insert = None;
2856
2857        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2858        while let Some(edit) = excerpt_edits.next() {
2859            excerpts.seek_forward(&edit.new.start, Bias::Right);
2860            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2861                excerpts.prev();
2862            }
2863
2864            // Keep any transforms that are before the edit.
2865            if at_transform_boundary {
2866                at_transform_boundary = false;
2867                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2868                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2869                if let Some(transform) = old_diff_transforms.item()
2870                    && old_diff_transforms.end().0 == edit.old.start
2871                    && old_diff_transforms.start().0 < edit.old.start
2872                {
2873                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2874                    old_diff_transforms.next();
2875                }
2876            }
2877
2878            // Compute the start of the edit in output coordinates.
2879            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
2880            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2881            let edit_new_start =
2882                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2883
2884            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2885                &edit,
2886                &mut excerpts,
2887                &mut old_diff_transforms,
2888                &mut new_diff_transforms,
2889                &mut end_of_current_insert,
2890                &mut old_expanded_hunks,
2891                snapshot,
2892                change_kind,
2893            );
2894
2895            // Compute the end of the edit in output coordinates.
2896            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2897            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2898            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
2899            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
2900            let output_edit = Edit {
2901                old: edit_old_start..edit_old_end,
2902                new: edit_new_start..edit_new_end,
2903            };
2904
2905            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2906            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2907            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2908                output_edits.push(output_edit);
2909            }
2910
2911            // If this is the last edit that intersects the current diff transform,
2912            // then recreate the content up to the end of this transform, to prepare
2913            // for reusing additional slices of the old transforms.
2914            if excerpt_edits
2915                .peek()
2916                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2917            {
2918                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2919                    && match old_diff_transforms.item() {
2920                        Some(DiffTransform::BufferContent {
2921                            inserted_hunk_info: Some(hunk),
2922                            ..
2923                        }) => excerpts.item().is_some_and(|excerpt| {
2924                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
2925                                && diff.main_buffer.is_some()
2926                            {
2927                                return true;
2928                            }
2929                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2930                        }),
2931                        _ => true,
2932                    };
2933
2934                let mut excerpt_offset = edit.new.end;
2935                if !keep_next_old_transform {
2936                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2937                    old_diff_transforms.next();
2938                }
2939
2940                old_expanded_hunks.clear();
2941                Self::push_buffer_content_transform(
2942                    snapshot,
2943                    &mut new_diff_transforms,
2944                    excerpt_offset,
2945                    end_of_current_insert,
2946                );
2947                at_transform_boundary = true;
2948            }
2949        }
2950
2951        // Keep any transforms that are after the last edit.
2952        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
2953
2954        // Ensure there's always at least one buffer content transform.
2955        if new_diff_transforms.is_empty() {
2956            new_diff_transforms.push(
2957                DiffTransform::BufferContent {
2958                    summary: Default::default(),
2959                    inserted_hunk_info: None,
2960                },
2961                (),
2962            );
2963        }
2964
2965        drop(old_diff_transforms);
2966        drop(excerpts);
2967        snapshot.diff_transforms = new_diff_transforms;
2968        snapshot.edit_count += 1;
2969
2970        #[cfg(any(test, feature = "test-support"))]
2971        snapshot.check_invariants();
2972        output_edits
2973    }
2974
2975    fn recompute_diff_transforms_for_edit(
2976        edit: &Edit<ExcerptOffset>,
2977        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
2978        old_diff_transforms: &mut Cursor<
2979            DiffTransform,
2980            Dimensions<ExcerptOffset, MultiBufferOffset>,
2981        >,
2982        new_diff_transforms: &mut SumTree<DiffTransform>,
2983        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
2984        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
2985        snapshot: &MultiBufferSnapshot,
2986        change_kind: DiffChangeKind,
2987    ) -> bool {
2988        log::trace!(
2989            "recomputing diff transform for edit {:?} => {:?}",
2990            edit.old.start..edit.old.end,
2991            edit.new.start..edit.new.end
2992        );
2993
2994        // Record which hunks were previously expanded.
2995        while let Some(item) = old_diff_transforms.item() {
2996            if let Some(hunk_info) = item.hunk_info() {
2997                log::trace!(
2998                    "previously expanded hunk at {:?}",
2999                    old_diff_transforms.start()
3000                );
3001                old_expanded_hunks.insert(hunk_info);
3002            }
3003            if old_diff_transforms.end().0 > edit.old.end {
3004                break;
3005            }
3006            old_diff_transforms.next();
3007        }
3008
3009        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3010        // For inverted diffs, hunks are always shown, so we can't skip this.
3011        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3012        if old_expanded_hunks.is_empty()
3013            && change_kind == DiffChangeKind::BufferEdited
3014            && !all_diff_hunks_expanded
3015            && !snapshot.has_inverted_diff
3016        {
3017            return false;
3018        }
3019
3020        // Visit each excerpt that intersects the edit.
3021        let mut did_expand_hunks = false;
3022        while let Some(excerpt) = excerpts.item() {
3023            // Recompute the expanded hunks in the portion of the excerpt that
3024            // intersects the edit.
3025            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3026                let buffer = &excerpt.buffer;
3027                let excerpt_start = *excerpts.start();
3028                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3029                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3030                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3031                let edit_buffer_start =
3032                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3033                let edit_buffer_end =
3034                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3035                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3036
3037                if let Some(main_buffer) = &diff.main_buffer {
3038                    for hunk in diff.hunks_intersecting_base_text_range(
3039                        edit_buffer_start..edit_buffer_end,
3040                        main_buffer,
3041                    ) {
3042                        did_expand_hunks = true;
3043                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3044                        if hunk_buffer_range.start < excerpt_buffer_start {
3045                            log::trace!("skipping hunk that starts before excerpt");
3046                            continue;
3047                        }
3048                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3049                        let hunk_excerpt_start = excerpt_start
3050                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3051                        let hunk_excerpt_end = excerpt_end
3052                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3053                        Self::push_buffer_content_transform(
3054                            snapshot,
3055                            new_diff_transforms,
3056                            hunk_excerpt_start,
3057                            *end_of_current_insert,
3058                        );
3059                        if !hunk_buffer_range.is_empty() {
3060                            let hunk_info = DiffTransformHunkInfo {
3061                                excerpt_id: excerpt.id,
3062                                hunk_start_anchor: hunk.buffer_range.start,
3063                                hunk_secondary_status: hunk.secondary_status,
3064                                is_logically_deleted: true,
3065                            };
3066                            *end_of_current_insert =
3067                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3068                        }
3069                    }
3070                } else {
3071                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3072                        ..buffer.anchor_after(edit_buffer_end);
3073                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3074                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3075                            continue;
3076                        }
3077
3078                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3079                        if hunk_buffer_range.start < excerpt_buffer_start {
3080                            log::trace!("skipping hunk that starts before excerpt");
3081                            continue;
3082                        }
3083
3084                        let hunk_info = DiffTransformHunkInfo {
3085                            excerpt_id: excerpt.id,
3086                            hunk_start_anchor: hunk.buffer_range.start,
3087                            hunk_secondary_status: hunk.secondary_status,
3088                            is_logically_deleted: false,
3089                        };
3090
3091                        let hunk_excerpt_start = excerpt_start
3092                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3093                        let hunk_excerpt_end = excerpt_end
3094                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3095
3096                        Self::push_buffer_content_transform(
3097                            snapshot,
3098                            new_diff_transforms,
3099                            hunk_excerpt_start,
3100                            *end_of_current_insert,
3101                        );
3102
3103                        // For every existing hunk, determine if it was previously expanded
3104                        // and if it should currently be expanded.
3105                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3106                        let should_expand_hunk = match &change_kind {
3107                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3108                                was_previously_expanded || all_diff_hunks_expanded
3109                            }
3110                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3111                                let intersects = hunk_buffer_range.is_empty()
3112                                    || hunk_buffer_range.end > edit_buffer_start;
3113                                if *expand {
3114                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3115                                } else {
3116                                    !intersects
3117                                        && (was_previously_expanded || all_diff_hunks_expanded)
3118                                }
3119                            }
3120                            _ => was_previously_expanded || all_diff_hunks_expanded,
3121                        };
3122
3123                        if should_expand_hunk {
3124                            did_expand_hunks = true;
3125                            log::trace!(
3126                                "expanding hunk {:?}, excerpt:{:?}",
3127                                hunk_excerpt_start..hunk_excerpt_end,
3128                                excerpt.id
3129                            );
3130
3131                            if !hunk.diff_base_byte_range.is_empty()
3132                                && hunk_buffer_range.start >= edit_buffer_start
3133                                && hunk_buffer_range.start <= excerpt_buffer_end
3134                                && snapshot.show_deleted_hunks
3135                            {
3136                                let base_text = diff.base_text();
3137                                let mut text_cursor =
3138                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3139                                let mut base_text_summary = text_cursor
3140                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3141
3142                                let mut has_trailing_newline = false;
3143                                if base_text_summary.last_line_chars > 0 {
3144                                    base_text_summary += TextSummary::newline();
3145                                    has_trailing_newline = true;
3146                                }
3147
3148                                new_diff_transforms.push(
3149                                    DiffTransform::DeletedHunk {
3150                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3151                                        summary: base_text_summary,
3152                                        buffer_id: excerpt.buffer_id,
3153                                        hunk_info,
3154                                        has_trailing_newline,
3155                                    },
3156                                    (),
3157                                );
3158                            }
3159
3160                            if !hunk_buffer_range.is_empty() {
3161                                *end_of_current_insert =
3162                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3163                            }
3164                        }
3165                    }
3166                }
3167            }
3168
3169            if excerpts.end() <= edit.new.end {
3170                excerpts.next();
3171            } else {
3172                break;
3173            }
3174        }
3175
3176        did_expand_hunks || !old_expanded_hunks.is_empty()
3177    }
3178
3179    fn append_diff_transforms(
3180        new_transforms: &mut SumTree<DiffTransform>,
3181        subtree: SumTree<DiffTransform>,
3182    ) {
3183        if let Some(DiffTransform::BufferContent {
3184            inserted_hunk_info,
3185            summary,
3186        }) = subtree.first()
3187            && Self::extend_last_buffer_content_transform(
3188                new_transforms,
3189                *inserted_hunk_info,
3190                *summary,
3191            )
3192        {
3193            let mut cursor = subtree.cursor::<()>(());
3194            cursor.next();
3195            cursor.next();
3196            new_transforms.append(cursor.suffix(), ());
3197            return;
3198        }
3199        new_transforms.append(subtree, ());
3200    }
3201
3202    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3203        if let DiffTransform::BufferContent {
3204            inserted_hunk_info: inserted_hunk_anchor,
3205            summary,
3206        } = transform
3207            && Self::extend_last_buffer_content_transform(
3208                new_transforms,
3209                inserted_hunk_anchor,
3210                summary,
3211            )
3212        {
3213            return;
3214        }
3215        new_transforms.push(transform, ());
3216    }
3217
3218    fn push_buffer_content_transform(
3219        old_snapshot: &MultiBufferSnapshot,
3220        new_transforms: &mut SumTree<DiffTransform>,
3221        end_offset: ExcerptOffset,
3222        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3223    ) {
3224        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3225            (end_offset.min(insertion_end_offset), Some(hunk_info))
3226        });
3227        let unchanged_region = [(end_offset, None)];
3228
3229        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3230        {
3231            let start_offset = new_transforms.summary().excerpt_len();
3232            if end_offset <= start_offset {
3233                continue;
3234            }
3235            let summary_to_add = old_snapshot
3236                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3237
3238            if !Self::extend_last_buffer_content_transform(
3239                new_transforms,
3240                inserted_hunk_info,
3241                summary_to_add,
3242            ) {
3243                new_transforms.push(
3244                    DiffTransform::BufferContent {
3245                        summary: summary_to_add,
3246                        inserted_hunk_info,
3247                    },
3248                    (),
3249                )
3250            }
3251        }
3252    }
3253
3254    fn extend_last_buffer_content_transform(
3255        new_transforms: &mut SumTree<DiffTransform>,
3256        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3257        summary_to_add: MBTextSummary,
3258    ) -> bool {
3259        let mut did_extend = false;
3260        new_transforms.update_last(
3261            |last_transform| {
3262                if let DiffTransform::BufferContent {
3263                    summary,
3264                    inserted_hunk_info: inserted_hunk_anchor,
3265                } = last_transform
3266                    && *inserted_hunk_anchor == new_inserted_hunk_info
3267                {
3268                    *summary += summary_to_add;
3269                    did_extend = true;
3270                }
3271            },
3272            (),
3273        );
3274        did_extend
3275    }
3276
3277    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3278        let snapshot = self.snapshot(cx);
3279        let excerpt_id = range.end.excerpt_id;
3280        let point_range = range.to_point(&snapshot);
3281        let expand = !self.single_hunk_is_expanded(range, cx);
3282        let edits =
3283            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3284        if !edits.is_empty() {
3285            self.subscriptions.publish(edits);
3286        }
3287        cx.emit(Event::DiffHunksToggled);
3288        cx.emit(Event::Edited {
3289            edited_buffer: None,
3290        });
3291    }
3292}
3293
3294fn build_excerpt_ranges(
3295    ranges: impl IntoIterator<Item = Range<Point>>,
3296    context_line_count: u32,
3297    buffer_snapshot: &BufferSnapshot,
3298) -> Vec<ExcerptRange<Point>> {
3299    ranges
3300        .into_iter()
3301        .map(|range| {
3302            let start_row = range.start.row.saturating_sub(context_line_count);
3303            let start = Point::new(start_row, 0);
3304            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3305            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3306            ExcerptRange {
3307                context: start..end,
3308                primary: range,
3309            }
3310        })
3311        .collect()
3312}
3313
3314#[cfg(any(test, feature = "test-support"))]
3315impl MultiBuffer {
3316    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3317        let buffer = cx.new(|cx| Buffer::local(text, cx));
3318        cx.new(|cx| Self::singleton(buffer, cx))
3319    }
3320
3321    pub fn build_multi<const COUNT: usize>(
3322        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3323        cx: &mut gpui::App,
3324    ) -> Entity<Self> {
3325        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3326        for (ix, (text, ranges)) in excerpts.into_iter().enumerate() {
3327            let buffer = cx.new(|cx| Buffer::local(text, cx));
3328            let snapshot = buffer.read(cx).snapshot();
3329            let excerpt_ranges = ranges
3330                .into_iter()
3331                .map(ExcerptRange::new)
3332                .collect::<Vec<_>>();
3333            multi.update(cx, |multi, cx| {
3334                multi.set_excerpt_ranges_for_path(
3335                    PathKey::sorted(ix as u64),
3336                    buffer,
3337                    &snapshot,
3338                    excerpt_ranges,
3339                    cx,
3340                )
3341            });
3342        }
3343
3344        multi
3345    }
3346
3347    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3348        cx.new(|cx| Self::singleton(buffer, cx))
3349    }
3350
3351    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3352        cx.new(|cx| {
3353            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3354            let mutation_count = rng.random_range(1..=5);
3355            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3356            multibuffer
3357        })
3358    }
3359
3360    pub fn randomly_edit(
3361        &mut self,
3362        rng: &mut impl rand::Rng,
3363        edit_count: usize,
3364        cx: &mut Context<Self>,
3365    ) {
3366        use util::RandomCharIter;
3367
3368        let snapshot = self.read(cx);
3369        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3370        let mut last_end = None;
3371        for _ in 0..edit_count {
3372            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3373                break;
3374            }
3375
3376            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3377            let end =
3378                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3379            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3380            last_end = Some(end);
3381
3382            let mut range = start..end;
3383            if rng.random_bool(0.2) {
3384                mem::swap(&mut range.start, &mut range.end);
3385            }
3386
3387            let new_text_len = rng.random_range(0..10);
3388            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3389
3390            edits.push((range, new_text.into()));
3391        }
3392        log::info!("mutating multi-buffer with {:?}", edits);
3393        drop(snapshot);
3394
3395        self.edit(edits, None, cx);
3396    }
3397
3398    pub fn randomly_edit_excerpts(
3399        &mut self,
3400        rng: &mut impl rand::Rng,
3401        mutation_count: usize,
3402        cx: &mut Context<Self>,
3403    ) {
3404        use rand::prelude::*;
3405        use std::env;
3406        use util::RandomCharIter;
3407
3408        let max_excerpts = env::var("MAX_EXCERPTS")
3409            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3410            .unwrap_or(5);
3411
3412        let mut buffers = Vec::new();
3413        for _ in 0..mutation_count {
3414            if rng.random_bool(0.05) {
3415                log::info!("Clearing multi-buffer");
3416                self.clear(cx);
3417                continue;
3418            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3419                let ids = self.excerpt_ids();
3420                let mut excerpts = HashSet::default();
3421                for _ in 0..rng.random_range(0..ids.len()) {
3422                    excerpts.extend(ids.choose(rng).copied());
3423                }
3424
3425                let line_count = rng.random_range(0..5);
3426
3427                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3428
3429                self.expand_excerpts(
3430                    excerpts.iter().cloned(),
3431                    line_count,
3432                    ExpandExcerptDirection::UpAndDown,
3433                    cx,
3434                );
3435                continue;
3436            }
3437
3438            let excerpt_ids = self.excerpt_ids();
3439            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3440                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3441                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3442                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3443                    let buffer = buffers.last().unwrap().read(cx);
3444                    log::info!(
3445                        "Creating new buffer {} with text: {:?}",
3446                        buffer.remote_id(),
3447                        buffer.text()
3448                    );
3449                    buffers.last().unwrap().clone()
3450                } else {
3451                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3452                };
3453
3454                let buffer = buffer_handle.read(cx);
3455                let buffer_text = buffer.text();
3456                let ranges = (0..rng.random_range(0..5))
3457                    .map(|_| {
3458                        let end_ix =
3459                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3460                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3461                        ExcerptRange::new(start_ix..end_ix)
3462                    })
3463                    .collect::<Vec<_>>();
3464                log::info!(
3465                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3466                    buffer_handle.read(cx).remote_id(),
3467                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3468                    ranges
3469                        .iter()
3470                        .map(|r| &buffer_text[r.context.clone()])
3471                        .collect::<Vec<_>>()
3472                );
3473
3474                let excerpt_id =
3475                    self.insert_excerpts_after(ExcerptId::max(), buffer_handle, ranges, cx);
3476                log::info!("Inserted with ids: {:?}", excerpt_id);
3477            } else {
3478                let remove_count = rng.random_range(1..=excerpt_ids.len());
3479                let mut excerpts_to_remove = excerpt_ids
3480                    .choose_multiple(rng, remove_count)
3481                    .cloned()
3482                    .collect::<Vec<_>>();
3483                let snapshot = self.snapshot.borrow();
3484                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3485                drop(snapshot);
3486                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3487                self.remove_excerpts(excerpts_to_remove, cx);
3488            }
3489        }
3490    }
3491
3492    pub fn randomly_mutate(
3493        &mut self,
3494        rng: &mut impl rand::Rng,
3495        mutation_count: usize,
3496        cx: &mut Context<Self>,
3497    ) {
3498        use rand::prelude::*;
3499
3500        if rng.random_bool(0.7) || self.singleton {
3501            let buffer = self
3502                .buffers
3503                .values()
3504                .choose(rng)
3505                .map(|state| state.buffer.clone());
3506
3507            if let Some(buffer) = buffer {
3508                buffer.update(cx, |buffer, cx| {
3509                    if rng.random() {
3510                        buffer.randomly_edit(rng, mutation_count, cx);
3511                    } else {
3512                        buffer.randomly_undo_redo(rng, cx);
3513                    }
3514                });
3515            } else {
3516                self.randomly_edit(rng, mutation_count, cx);
3517            }
3518        } else {
3519            self.randomly_edit_excerpts(rng, mutation_count, cx);
3520        }
3521
3522        self.check_invariants(cx);
3523    }
3524
3525    fn check_invariants(&self, cx: &App) {
3526        self.read(cx).check_invariants();
3527    }
3528}
3529
3530impl EventEmitter<Event> for MultiBuffer {}
3531
3532impl MultiBufferSnapshot {
3533    pub fn text(&self) -> String {
3534        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3535            .map(|chunk| chunk.text)
3536            .collect()
3537    }
3538
3539    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3540        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3541            .flat_map(|c| c.chars().rev())
3542    }
3543
3544    fn reversed_chunks_in_range(
3545        &self,
3546        range: Range<MultiBufferOffset>,
3547    ) -> ReversedMultiBufferChunks<'_> {
3548        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3549        cursor.seek(&range.end);
3550        let current_chunks = cursor.region().as_ref().map(|region| {
3551            let start_overshoot = range.start.saturating_sub(region.range.start);
3552            let end_overshoot = range.end - region.range.start;
3553            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3554            let start = region.buffer_range.start + start_overshoot;
3555            region.buffer.reversed_chunks_in_range(start..end)
3556        });
3557        ReversedMultiBufferChunks {
3558            cursor,
3559            current_chunks,
3560            start: range.start,
3561            offset: range.end,
3562        }
3563    }
3564
3565    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3566        let offset = position.to_offset(self);
3567        self.text_for_range(offset..self.len())
3568            .flat_map(|chunk| chunk.chars())
3569    }
3570
3571    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3572        self.chunks(range, false).map(|chunk| chunk.text)
3573    }
3574
3575    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3576        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3577            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3578    }
3579
3580    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3581    where
3582        T: ToOffset,
3583    {
3584        let position = position.to_offset(self);
3585        position == self.clip_offset(position, Bias::Left)
3586            && self
3587                .bytes_in_range(position..self.len())
3588                .flatten()
3589                .copied()
3590                .take(needle.len())
3591                .eq(needle.bytes())
3592    }
3593
3594    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3595        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3596    }
3597
3598    pub fn diff_hunks_in_range<T: ToPoint>(
3599        &self,
3600        range: Range<T>,
3601    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3602        let query_range = range.start.to_point(self)..range.end.to_point(self);
3603        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3604            let diff = self.diffs.get(&buffer.remote_id())?;
3605            let iter = if let Some(main_buffer) = &diff.main_buffer {
3606                let buffer_start = buffer.point_to_offset(buffer_range.start);
3607                let buffer_end = buffer.point_to_offset(buffer_range.end);
3608                itertools::Either::Left(
3609                    diff.hunks_intersecting_base_text_range(buffer_start..buffer_end, main_buffer)
3610                        .map(move |hunk| (hunk, buffer, true)),
3611                )
3612            } else {
3613                let buffer_start = buffer.anchor_before(buffer_range.start);
3614                let buffer_end = buffer.anchor_after(buffer_range.end);
3615                itertools::Either::Right(
3616                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3617                        .map(move |hunk| (hunk, buffer, false)),
3618                )
3619            };
3620            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3621                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3622                    return None;
3623                }
3624                let range = if is_inverted {
3625                    hunk.diff_base_byte_range.to_point(&buffer)
3626                } else {
3627                    hunk.range.clone()
3628                };
3629                Some((range, (hunk, is_inverted)))
3630            }))
3631        })
3632        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3633            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3634            {
3635                return None;
3636            }
3637            let end_row = if range.end.column == 0 {
3638                range.end.row
3639            } else {
3640                range.end.row + 1
3641            };
3642
3643            let word_diffs =
3644                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3645                    .then(|| {
3646                        let mut word_diffs = Vec::new();
3647
3648                        if self.show_deleted_hunks || is_inverted {
3649                            let hunk_start_offset = if is_inverted {
3650                                Anchor::text(
3651                                    excerpt.id,
3652                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3653                                )
3654                                .to_offset(self)
3655                            } else {
3656                                Anchor::text(excerpt.id, hunk.buffer_range.start).to_offset(self)
3657                            };
3658
3659                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3660                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3661                            }));
3662                        }
3663
3664                        if !is_inverted {
3665                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3666                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3667                            }));
3668                        }
3669                        word_diffs
3670                    })
3671                    .unwrap_or_default();
3672
3673            let buffer_range = if is_inverted {
3674                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3675                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3676            } else {
3677                hunk.buffer_range.clone()
3678            };
3679            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3680                DiffHunkStatusKind::Deleted
3681            } else if hunk.diff_base_byte_range.is_empty() {
3682                DiffHunkStatusKind::Added
3683            } else {
3684                DiffHunkStatusKind::Modified
3685            };
3686            Some(MultiBufferDiffHunk {
3687                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3688                buffer_id: excerpt.buffer_id,
3689                excerpt_id: excerpt.id,
3690                buffer_range,
3691                word_diffs,
3692                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3693                    ..BufferOffset(hunk.diff_base_byte_range.end),
3694                status: DiffHunkStatus {
3695                    kind: status_kind,
3696                    secondary: hunk.secondary_status,
3697                },
3698            })
3699        })
3700    }
3701
3702    fn excerpts_for_range<T: ToOffset>(
3703        &self,
3704        range: Range<T>,
3705    ) -> impl Iterator<Item = &Excerpt> + '_ {
3706        let range = range.start.to_offset(self)..range.end.to_offset(self);
3707        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3708        cursor.seek(&range.start);
3709        std::iter::from_fn(move || {
3710            let region = cursor.region()?;
3711            if region.range.start > range.end
3712                || region.range.start == range.end && region.range.start > range.start
3713            {
3714                return None;
3715            }
3716            let excerpt = region.excerpt;
3717            cursor.next_excerpt_forwards();
3718            Some(excerpt)
3719        })
3720    }
3721
3722    pub fn excerpt_ids_for_range<T: ToOffset>(
3723        &self,
3724        range: Range<T>,
3725    ) -> impl Iterator<Item = ExcerptId> + '_ {
3726        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
3727    }
3728
3729    pub fn buffer_ids_for_range<T: ToOffset>(
3730        &self,
3731        range: Range<T>,
3732    ) -> impl Iterator<Item = BufferId> + '_ {
3733        self.excerpts_for_range(range)
3734            .map(|excerpt| excerpt.buffer_id)
3735    }
3736
3737    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
3738    ///
3739    /// The passed in anchors must be ordered.
3740    pub fn text_anchors_to_visible_anchors(
3741        &self,
3742        anchors: impl IntoIterator<Item = text::Anchor>,
3743    ) -> Vec<Option<Anchor>> {
3744        let anchors = anchors.into_iter();
3745        let mut result = Vec::with_capacity(anchors.size_hint().0);
3746        let mut anchors = anchors.peekable();
3747        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
3748        'anchors: while let Some(anchor) = anchors.peek() {
3749            let Some(buffer_id) = anchor.buffer_id else {
3750                anchors.next();
3751                result.push(None);
3752                continue 'anchors;
3753            };
3754            let mut same_buffer_anchors =
3755                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
3756
3757            if let Some(path) = self.path_keys_by_buffer.get(&buffer_id) {
3758                let Some(mut next) = same_buffer_anchors.next() else {
3759                    continue 'anchors;
3760                };
3761                cursor.seek_forward(path, Bias::Left);
3762                'excerpts: loop {
3763                    let Some(excerpt) = cursor.item() else {
3764                        break;
3765                    };
3766                    if &excerpt.path_key != path {
3767                        break;
3768                    }
3769
3770                    loop {
3771                        // anchor is before the first excerpt
3772                        if excerpt
3773                            .range
3774                            .context
3775                            .start
3776                            .cmp(&next, &excerpt.buffer)
3777                            .is_gt()
3778                        {
3779                            // so we skip it and try the next anchor
3780                            result.push(None);
3781                            match same_buffer_anchors.next() {
3782                                Some(anchor) => next = anchor,
3783                                None => continue 'anchors,
3784                            }
3785                        // anchor is within the excerpt
3786                        } else if excerpt
3787                            .range
3788                            .context
3789                            .end
3790                            .cmp(&next, &excerpt.buffer)
3791                            .is_ge()
3792                        {
3793                            // record it and all following anchors that are within
3794                            result.push(Some(Anchor::in_buffer(excerpt.path_key_index, next)));
3795                            result.extend(
3796                                same_buffer_anchors
3797                                    .peeking_take_while(|a| {
3798                                        excerpt.range.context.end.cmp(a, &excerpt.buffer).is_ge()
3799                                    })
3800                                    .map(|a| Some(Anchor::in_buffer(excerpt.path_key_index, a))),
3801                            );
3802                            match same_buffer_anchors.next() {
3803                                Some(anchor) => next = anchor,
3804                                None => continue 'anchors,
3805                            }
3806                        // anchor is after the excerpt, try the next one
3807                        } else {
3808                            cursor.next();
3809                            continue 'excerpts;
3810                        }
3811                    }
3812                }
3813                // account for `next`
3814                result.push(None);
3815            }
3816            result.extend(same_buffer_anchors.map(|_| None));
3817        }
3818
3819        result
3820    }
3821
3822    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3823        &self,
3824        ranges: impl Iterator<Item = Range<T>>,
3825    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3826        ranges.flat_map(|range| {
3827            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
3828                .into_iter()
3829        })
3830    }
3831
3832    pub fn range_to_buffer_ranges<R, T>(
3833        &self,
3834        range: R,
3835    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
3836    where
3837        R: RangeBounds<T>,
3838        T: ToOffset,
3839    {
3840        self.range_to_buffer_ranges_with_context(range)
3841            .into_iter()
3842            .map(|(buffer, range, id, _context)| (buffer, range, id))
3843            .collect()
3844    }
3845
3846    pub fn range_to_buffer_ranges_with_context<R, T>(
3847        &self,
3848        range: R,
3849    ) -> Vec<(
3850        &BufferSnapshot,
3851        Range<BufferOffset>,
3852        ExcerptId,
3853        Range<text::Anchor>,
3854    )>
3855    where
3856        R: RangeBounds<T>,
3857        T: ToOffset,
3858    {
3859        let start = match range.start_bound() {
3860            Bound::Included(start) => start.to_offset(self),
3861            Bound::Excluded(_) => panic!("excluded start bound not supported"),
3862            Bound::Unbounded => MultiBufferOffset::ZERO,
3863        };
3864        let end_bound = match range.end_bound() {
3865            Bound::Included(end) => Bound::Included(end.to_offset(self)),
3866            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
3867            Bound::Unbounded => Bound::Unbounded,
3868        };
3869        let bounds = (Bound::Included(start), end_bound);
3870
3871        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3872        cursor.seek(&start);
3873
3874        let mut result: Vec<(
3875            &BufferSnapshot,
3876            Range<BufferOffset>,
3877            ExcerptId,
3878            Range<text::Anchor>,
3879        )> = Vec::new();
3880        while let Some(region) = cursor.region() {
3881            let dominated_by_end_bound = match end_bound {
3882                Bound::Included(end) => region.range.start > end,
3883                Bound::Excluded(end) => region.range.start >= end,
3884                Bound::Unbounded => false,
3885            };
3886            if dominated_by_end_bound {
3887                break;
3888            }
3889            if region.is_main_buffer {
3890                let start_overshoot = start.saturating_sub(region.range.start);
3891                let end_offset = match end_bound {
3892                    Bound::Included(end) | Bound::Excluded(end) => end,
3893                    Bound::Unbounded => region.range.end,
3894                };
3895                let end_overshoot = end_offset.saturating_sub(region.range.start);
3896                let start = region
3897                    .buffer_range
3898                    .end
3899                    .min(region.buffer_range.start + start_overshoot);
3900                let end = region
3901                    .buffer_range
3902                    .end
3903                    .min(region.buffer_range.start + end_overshoot);
3904                let context = region.excerpt.range.context.clone();
3905                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
3906                    *excerpt_id == region.excerpt.id && prev_range.end == start
3907                }) {
3908                    prev.1.end = end;
3909                } else {
3910                    result.push((region.buffer, start..end, region.excerpt.id, context));
3911                }
3912            }
3913            cursor.next();
3914        }
3915
3916        if let Some(excerpt) = cursor.excerpt() {
3917            let dominated_by_prev_excerpt =
3918                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
3919            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
3920                let excerpt_position = self.len();
3921                if bounds.contains(&excerpt_position) {
3922                    let buffer_offset =
3923                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
3924                    let context = excerpt.range.context.clone();
3925                    result.push((
3926                        &excerpt.buffer,
3927                        buffer_offset..buffer_offset,
3928                        excerpt.id,
3929                        context,
3930                    ));
3931                }
3932            }
3933        }
3934
3935        result
3936    }
3937
3938    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3939        &self,
3940        range: Range<T>,
3941    ) -> impl Iterator<
3942        Item = (
3943            &BufferSnapshot,
3944            Range<BufferOffset>,
3945            ExcerptId,
3946            Option<Anchor>,
3947        ),
3948    > + '_ {
3949        let start = range.start.to_offset(self);
3950        let end = range.end.to_offset(self);
3951
3952        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3953        cursor.seek(&start);
3954
3955        std::iter::from_fn(move || {
3956            let region = cursor.region()?;
3957            if region.range.start > end {
3958                return None;
3959            }
3960            let start_overshoot = start.saturating_sub(region.range.start);
3961            let end_overshoot = end.saturating_sub(region.range.start);
3962            let start = region
3963                .buffer_range
3964                .end
3965                .min(region.buffer_range.start + start_overshoot);
3966            let end = region
3967                .buffer_range
3968                .end
3969                .min(region.buffer_range.start + end_overshoot);
3970
3971            let region_excerpt_id = region.excerpt.id;
3972            let deleted_hunk_anchor = if region.is_main_buffer {
3973                None
3974            } else {
3975                Some(self.anchor_before(region.range.start))
3976            };
3977            let result = (
3978                region.buffer,
3979                start..end,
3980                region_excerpt_id,
3981                deleted_hunk_anchor,
3982            );
3983            cursor.next();
3984            Some(result)
3985        })
3986    }
3987
3988    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3989    /// coordinates.
3990    ///
3991    /// The given callback will be called for every excerpt intersecting the given range. It will
3992    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3993    /// The callback should return an iterator of metadata items from that buffer, each paired
3994    /// with a buffer range.
3995    ///
3996    /// The returned iterator yields each of these metadata items, paired with its range in
3997    /// multi-buffer coordinates.
3998    fn lift_buffer_metadata<'a, MBD, M, I>(
3999        &'a self,
4000        query_range: Range<MBD>,
4001        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4002    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4003    where
4004        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4005        MBD: MultiBufferDimension
4006            + Ord
4007            + Sub<Output = MBD::TextDimension>
4008            + ops::Add<MBD::TextDimension, Output = MBD>
4009            + ops::AddAssign<MBD::TextDimension>,
4010        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4011            + ops::Add<Output = MBD::TextDimension>
4012            + AddAssign<MBD::TextDimension>
4013            + Ord,
4014    {
4015        let mut current_excerpt_metadata: Option<(Excerpt, I)> = None;
4016        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4017
4018        // Find the excerpt and buffer offset where the given range ends.
4019        cursor.seek(&query_range.end);
4020        let mut range_end = None;
4021        while let Some(region) = cursor.region() {
4022            if region.is_main_buffer {
4023                let mut buffer_end = region.buffer_range.start;
4024                let overshoot = if query_range.end > region.range.start {
4025                    query_range.end - region.range.start
4026                } else {
4027                    <MBD::TextDimension>::default()
4028                };
4029                buffer_end = buffer_end + overshoot;
4030                range_end = Some((region.excerpt, buffer_end));
4031                break;
4032            }
4033            cursor.next();
4034        }
4035
4036        cursor.seek(&query_range.start);
4037
4038        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4039            && region.range.start > MBD::default()
4040        {
4041            cursor.prev()
4042        } else if let Some(region) = cursor.region()
4043            && region.is_main_buffer
4044            && region.diff_hunk_status.is_some()
4045        {
4046            cursor.prev();
4047            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4048                cursor.next();
4049            }
4050        }
4051
4052        iter::from_fn(move || {
4053            loop {
4054                let excerpt = cursor.excerpt()?;
4055
4056                // If we have already retrieved metadata for this excerpt, continue to use it.
4057                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4058                    .as_mut()
4059                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4060                {
4061                    Some(metadata)
4062                }
4063                // Otherwise, compute the intersection of the input range with the excerpt's range,
4064                // and retrieve the metadata for the resulting range.
4065                else {
4066                    let region = cursor.region()?;
4067                    let mut buffer_start;
4068                    if region.is_main_buffer {
4069                        buffer_start = region.buffer_range.start;
4070                        if query_range.start > region.range.start {
4071                            let overshoot = query_range.start - region.range.start;
4072                            buffer_start = buffer_start + overshoot;
4073                        }
4074                        buffer_start = buffer_start.min(region.buffer_range.end);
4075                    } else {
4076                        buffer_start = cursor.main_buffer_position()?;
4077                    };
4078                    let mut buffer_end = excerpt
4079                        .range
4080                        .context
4081                        .end
4082                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4083                    if let Some((end_excerpt, end_buffer_offset)) = range_end
4084                        && excerpt == end_excerpt
4085                    {
4086                        buffer_end = buffer_end.min(end_buffer_offset);
4087                    }
4088
4089                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
4090                        .map(|iterator| &mut current_excerpt_metadata.insert((excerpt, iterator)).1)
4091                };
4092
4093                // Visit each metadata item.
4094                if let Some((metadata_buffer_range, metadata)) =
4095                    metadata_iter.and_then(Iterator::next)
4096                {
4097                    // Find the multibuffer regions that contain the start and end of
4098                    // the metadata item's range.
4099                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4100                        while let Some(region) = cursor.region() {
4101                            if (region.is_main_buffer
4102                                && (region.buffer_range.end >= metadata_buffer_range.start
4103                                    || cursor.is_at_end_of_excerpt()))
4104                                || (!region.is_main_buffer
4105                                    && region.buffer_range.start == metadata_buffer_range.start)
4106                            {
4107                                break;
4108                            }
4109                            cursor.next();
4110                        }
4111                    }
4112                    let start_region = cursor.region()?.clone();
4113                    while let Some(region) = cursor.region() {
4114                        if region.is_main_buffer
4115                            && (region.buffer_range.end > metadata_buffer_range.end
4116                                || cursor.is_at_end_of_excerpt())
4117                        {
4118                            break;
4119                        }
4120                        cursor.next();
4121                    }
4122                    let end_region = cursor.region();
4123
4124                    // Convert the metadata item's range into multibuffer coordinates.
4125                    let mut start_position = start_region.range.start;
4126                    let region_buffer_start = start_region.buffer_range.start;
4127                    if start_region.is_main_buffer
4128                        && metadata_buffer_range.start > region_buffer_start
4129                    {
4130                        start_position =
4131                            start_position + (metadata_buffer_range.start - region_buffer_start);
4132                        start_position = start_position.min(start_region.range.end);
4133                    }
4134
4135                    let mut end_position = self.max_position();
4136                    if let Some(end_region) = &end_region {
4137                        end_position = end_region.range.start;
4138                        debug_assert!(end_region.is_main_buffer);
4139                        let region_buffer_start = end_region.buffer_range.start;
4140                        if metadata_buffer_range.end > region_buffer_start {
4141                            end_position =
4142                                end_position + (metadata_buffer_range.end - region_buffer_start);
4143                        }
4144                        end_position = end_position.min(end_region.range.end);
4145                    }
4146
4147                    if start_position <= query_range.end && end_position >= query_range.start {
4148                        return Some((start_position..end_position, metadata, excerpt));
4149                    }
4150                }
4151                // When there are no more metadata items for this excerpt, move to the next excerpt.
4152                else {
4153                    current_excerpt_metadata.take();
4154                    if let Some((end_excerpt, _)) = range_end
4155                        && excerpt == end_excerpt
4156                    {
4157                        return None;
4158                    }
4159                    cursor.next_excerpt_forwards();
4160                }
4161            }
4162        })
4163    }
4164
4165    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4166        let offset = position.to_offset(self);
4167
4168        let mut cursor = self
4169            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4170            );
4171        cursor.seek(&DimensionPair {
4172            key: offset,
4173            value: None,
4174        });
4175        cursor.seek_to_start_of_current_excerpt();
4176        let excerpt = cursor.excerpt()?;
4177
4178        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4179        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4180        let current_position = match self.anchor_before(offset) {
4181            Anchor::Min => 0,
4182            Anchor::Excerpt(excerpt_anchor) => {
4183                excerpt_anchor.text_anchor().to_offset(&excerpt.buffer)
4184            }
4185            Anchor::Max => unreachable!(),
4186        };
4187
4188        if let Some(diff) = self.diffs.get(&excerpt.buffer.remote_id()) {
4189            if let Some(main_buffer) = &diff.main_buffer {
4190                for hunk in diff
4191                    .hunks_intersecting_base_text_range_rev(excerpt_start..excerpt_end, main_buffer)
4192                {
4193                    if hunk.diff_base_byte_range.end >= current_position {
4194                        continue;
4195                    }
4196                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4197                    let start =
4198                        Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4199                    return Some(MultiBufferRow(start.row));
4200                }
4201            } else {
4202                let excerpt_end = excerpt
4203                    .buffer
4204                    .anchor_before(excerpt_end.min(current_position));
4205                for hunk in diff.hunks_intersecting_range_rev(
4206                    excerpt.range.context.start..excerpt_end,
4207                    &excerpt.buffer,
4208                ) {
4209                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4210                    if hunk_end >= current_position {
4211                        continue;
4212                    }
4213                    let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4214                        .to_point(self);
4215                    return Some(MultiBufferRow(start.row));
4216                }
4217            }
4218        }
4219
4220        loop {
4221            cursor.prev_excerpt();
4222            let excerpt = cursor.excerpt()?;
4223
4224            let Some(diff) = self.diffs.get(&excerpt.buffer.remote_id()) else {
4225                continue;
4226            };
4227            if let Some(main_buffer) = &diff.main_buffer {
4228                let Some(hunk) = diff
4229                    .hunks_intersecting_base_text_range_rev(
4230                        excerpt.range.context.to_offset(&excerpt.buffer),
4231                        main_buffer,
4232                    )
4233                    .next()
4234                else {
4235                    continue;
4236                };
4237                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4238                let start = Anchor::in_buffer(excerpt.path_key_index, hunk_start).to_point(self);
4239                return Some(MultiBufferRow(start.row));
4240            } else {
4241                let Some(hunk) = diff
4242                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4243                    .next()
4244                else {
4245                    continue;
4246                };
4247                let start = Anchor::in_buffer(excerpt.path_key_index, hunk.buffer_range.start)
4248                    .to_point(self);
4249                return Some(MultiBufferRow(start.row));
4250            }
4251        }
4252    }
4253
4254    pub fn has_diff_hunks(&self) -> bool {
4255        self.diffs.values().any(|diff| !diff.is_empty())
4256    }
4257
4258    pub fn is_inside_word<T: ToOffset>(
4259        &self,
4260        position: T,
4261        scope_context: Option<CharScopeContext>,
4262    ) -> bool {
4263        let position = position.to_offset(self);
4264        let classifier = self
4265            .char_classifier_at(position)
4266            .scope_context(scope_context);
4267        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4268        let prev_char_kind = self
4269            .reversed_chars_at(position)
4270            .next()
4271            .map(|c| classifier.kind(c));
4272        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4273    }
4274
4275    pub fn surrounding_word<T: ToOffset>(
4276        &self,
4277        start: T,
4278        scope_context: Option<CharScopeContext>,
4279    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4280        let mut start = start.to_offset(self);
4281        let mut end = start;
4282        let mut next_chars = self.chars_at(start).peekable();
4283        let mut prev_chars = self.reversed_chars_at(start).peekable();
4284
4285        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4286
4287        let word_kind = cmp::max(
4288            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4289            next_chars.peek().copied().map(|c| classifier.kind(c)),
4290        );
4291
4292        for ch in prev_chars {
4293            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4294                start -= ch.len_utf8();
4295            } else {
4296                break;
4297            }
4298        }
4299
4300        for ch in next_chars {
4301            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4302                end += ch.len_utf8();
4303            } else {
4304                break;
4305            }
4306        }
4307
4308        (start..end, word_kind)
4309    }
4310
4311    pub fn char_kind_before<T: ToOffset>(
4312        &self,
4313        start: T,
4314        scope_context: Option<CharScopeContext>,
4315    ) -> Option<CharKind> {
4316        let start = start.to_offset(self);
4317        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4318        self.reversed_chars_at(start)
4319            .next()
4320            .map(|ch| classifier.kind(ch))
4321    }
4322
4323    pub fn is_singleton(&self) -> bool {
4324        self.singleton
4325    }
4326
4327    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4328        if self.singleton {
4329            self.excerpts
4330                .iter()
4331                .next()
4332                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4333        } else {
4334            None
4335        }
4336    }
4337
4338    pub fn len(&self) -> MultiBufferOffset {
4339        self.diff_transforms.summary().output.len
4340    }
4341
4342    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4343        MBD::from_summary(&self.text_summary())
4344    }
4345
4346    pub fn is_empty(&self) -> bool {
4347        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4348    }
4349
4350    pub fn widest_line_number(&self) -> u32 {
4351        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4352        self.excerpts.summary().widest_line_number + 1
4353    }
4354
4355    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4356        let range = range.start.to_offset(self)..range.end.to_offset(self);
4357        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4358        excerpts.seek(&range.start);
4359
4360        let mut chunk;
4361        let mut has_trailing_newline;
4362        let excerpt_bytes;
4363        if let Some(region) = excerpts.region() {
4364            let mut bytes = region.buffer.bytes_in_range(
4365                region.buffer_range.start + (range.start - region.range.start)
4366                    ..(region.buffer_range.start + (range.end - region.range.start))
4367                        .min(region.buffer_range.end),
4368            );
4369            chunk = bytes.next().unwrap_or(&[][..]);
4370            excerpt_bytes = Some(bytes);
4371            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4372            if chunk.is_empty() && has_trailing_newline {
4373                chunk = b"\n";
4374                has_trailing_newline = false;
4375            }
4376        } else {
4377            chunk = &[][..];
4378            excerpt_bytes = None;
4379            has_trailing_newline = false;
4380        };
4381
4382        MultiBufferBytes {
4383            range,
4384            cursor: excerpts,
4385            excerpt_bytes,
4386            has_trailing_newline,
4387            chunk,
4388        }
4389    }
4390
4391    pub fn reversed_bytes_in_range<T: ToOffset>(
4392        &self,
4393        range: Range<T>,
4394    ) -> ReversedMultiBufferBytes<'_> {
4395        let range = range.start.to_offset(self)..range.end.to_offset(self);
4396        let mut chunks = self.reversed_chunks_in_range(range.clone());
4397        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4398        ReversedMultiBufferBytes {
4399            range,
4400            chunks,
4401            chunk,
4402        }
4403    }
4404
4405    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4406        let mut cursor = self.cursor::<Point, Point>();
4407        cursor.seek(&Point::new(start_row.0, 0));
4408        let mut result = MultiBufferRows {
4409            point: Point::new(0, 0),
4410            is_empty: self.excerpts.is_empty(),
4411            is_singleton: self.is_singleton(),
4412            cursor,
4413        };
4414        result.seek(start_row);
4415        result
4416    }
4417
4418    pub fn chunks<T: ToOffset>(
4419        &self,
4420        range: Range<T>,
4421        language_aware: bool,
4422    ) -> MultiBufferChunks<'_> {
4423        let mut chunks = MultiBufferChunks {
4424            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4425                ..ExcerptDimension(MultiBufferOffset::ZERO),
4426            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4427            excerpts: self.excerpts.cursor(()),
4428            diff_transforms: self.diff_transforms.cursor(()),
4429            diffs: &self.diffs,
4430            diff_base_chunks: None,
4431            excerpt_chunks: None,
4432            buffer_chunk: None,
4433            language_aware,
4434        };
4435        let range = range.start.to_offset(self)..range.end.to_offset(self);
4436        chunks.seek(range);
4437        chunks
4438    }
4439
4440    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4441        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4442    }
4443
4444    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4445        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4446    }
4447
4448    pub fn clip_offset_utf16(
4449        &self,
4450        offset: MultiBufferOffsetUtf16,
4451        bias: Bias,
4452    ) -> MultiBufferOffsetUtf16 {
4453        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4454    }
4455
4456    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4457        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4458            buffer.clip_point_utf16(Unclipped(point), bias)
4459        })
4460    }
4461
4462    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4463        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4464    }
4465
4466    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4467        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4468    }
4469
4470    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4471        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4472    }
4473
4474    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4475        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4476    }
4477
4478    #[instrument(skip_all)]
4479    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4480        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4481    }
4482
4483    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4484        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4485    }
4486
4487    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4488        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4489    }
4490
4491    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4492        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4493    }
4494
4495    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4496        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4497    }
4498
4499    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4500        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4501    }
4502
4503    fn clip_dimension<MBD, BD>(
4504        &self,
4505        position: MBD,
4506        bias: Bias,
4507        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4508    ) -> MBD
4509    where
4510        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4511        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4512    {
4513        let mut cursor = self.cursor::<MBD, BD>();
4514        cursor.seek(&position);
4515        if let Some(region) = cursor.region() {
4516            if position >= region.range.end {
4517                return region.range.end;
4518            }
4519            let overshoot = position - region.range.start;
4520            let mut buffer_position = region.buffer_range.start;
4521            buffer_position += overshoot;
4522            let clipped_buffer_position =
4523                clip_buffer_position(region.buffer, buffer_position, bias);
4524            let mut position = region.range.start;
4525            position += clipped_buffer_position - region.buffer_range.start;
4526            position
4527        } else {
4528            self.max_position()
4529        }
4530    }
4531
4532    #[instrument(skip_all)]
4533    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4534        &self,
4535        key: MBR1,
4536        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4537    ) -> MBR2
4538    where
4539        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4540        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4541        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4542        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4543    {
4544        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4545        cursor.seek(&DimensionPair { key, value: None });
4546        if let Some(region) = cursor.region() {
4547            if key >= region.range.end.key {
4548                return region.range.end.value.unwrap();
4549            }
4550            let start_key = region.range.start.key;
4551            let start_value = region.range.start.value.unwrap();
4552            let buffer_start_key = region.buffer_range.start.key;
4553            let buffer_start_value = region.buffer_range.start.value.unwrap();
4554            let mut buffer_key = buffer_start_key;
4555            buffer_key += key - start_key;
4556            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4557            let mut result = start_value;
4558            result += buffer_value - buffer_start_value;
4559            result
4560        } else {
4561            self.max_position()
4562        }
4563    }
4564
4565    pub fn point_to_buffer_offset<T: ToOffset>(
4566        &self,
4567        point: T,
4568    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4569        let offset = point.to_offset(self);
4570        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4571        cursor.seek(&offset);
4572        let region = cursor.region()?;
4573        let overshoot = offset - region.range.start;
4574        let buffer_offset = region.buffer_range.start + overshoot;
4575        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4576            && region.has_trailing_newline
4577            && !region.is_main_buffer
4578        {
4579            let main_buffer_position = cursor.main_buffer_position()?;
4580            let buffer_snapshot = &cursor.excerpt()?.buffer;
4581            return Some((buffer_snapshot, main_buffer_position));
4582        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4583            return None;
4584        }
4585        Some((region.buffer, buffer_offset))
4586    }
4587
4588    pub fn point_to_buffer_point(&self, point: Point) -> Option<(&BufferSnapshot, Point)> {
4589        let mut cursor = self.cursor::<Point, Point>();
4590        cursor.seek(&point);
4591        let region = cursor.region()?;
4592        let overshoot = point - region.range.start;
4593        let buffer_point = region.buffer_range.start + overshoot;
4594        let excerpt = cursor.excerpt()?;
4595        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4596            && region.has_trailing_newline
4597            && !region.is_main_buffer
4598        {
4599            return Some((&excerpt.buffer, cursor.main_buffer_position()?));
4600        } else if buffer_point > region.buffer.max_point() {
4601            return None;
4602        }
4603        Some((region.buffer, buffer_point))
4604    }
4605
4606    pub fn suggested_indents(
4607        &self,
4608        rows: impl IntoIterator<Item = u32>,
4609        cx: &App,
4610    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4611        let mut result = BTreeMap::new();
4612        self.suggested_indents_callback(
4613            rows,
4614            &mut |row, indent| {
4615                result.insert(row, indent);
4616                ControlFlow::Continue(())
4617            },
4618            cx,
4619        );
4620        result
4621    }
4622
4623    // move this to be a generator once those are a thing
4624    pub fn suggested_indents_callback(
4625        &self,
4626        rows: impl IntoIterator<Item = u32>,
4627        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4628        cx: &App,
4629    ) {
4630        let mut rows_for_excerpt = Vec::new();
4631        let mut cursor = self.cursor::<Point, Point>();
4632        let mut rows = rows.into_iter().peekable();
4633        let mut prev_row = u32::MAX;
4634        let mut prev_language_indent_size = IndentSize::default();
4635
4636        while let Some(row) = rows.next() {
4637            cursor.seek(&Point::new(row, 0));
4638            let Some(region) = cursor.region() else {
4639                continue;
4640            };
4641
4642            // Retrieve the language and indent size once for each disjoint region being indented.
4643            let single_indent_size = if row.saturating_sub(1) == prev_row {
4644                prev_language_indent_size
4645            } else {
4646                region
4647                    .buffer
4648                    .language_indent_size_at(Point::new(row, 0), cx)
4649            };
4650            prev_language_indent_size = single_indent_size;
4651            prev_row = row;
4652
4653            let start_buffer_row = region.buffer_range.start.row;
4654            let start_multibuffer_row = region.range.start.row;
4655            let end_multibuffer_row = region.range.end.row;
4656
4657            rows_for_excerpt.push(row);
4658            while let Some(next_row) = rows.peek().copied() {
4659                if end_multibuffer_row > next_row {
4660                    rows_for_excerpt.push(next_row);
4661                    rows.next();
4662                } else {
4663                    break;
4664                }
4665            }
4666
4667            let buffer_rows = rows_for_excerpt
4668                .drain(..)
4669                .map(|row| start_buffer_row + row - start_multibuffer_row);
4670            let buffer_indents = region
4671                .buffer
4672                .suggested_indents(buffer_rows, single_indent_size);
4673            for (row, indent) in buffer_indents {
4674                if cb(
4675                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4676                    indent,
4677                )
4678                .is_break()
4679                {
4680                    return;
4681                }
4682            }
4683        }
4684    }
4685
4686    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4687        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4688            let mut size = buffer.indent_size_for_line(range.start.row);
4689            size.len = size
4690                .len
4691                .min(range.end.column)
4692                .saturating_sub(range.start.column);
4693            size
4694        } else {
4695            IndentSize::spaces(0)
4696        }
4697    }
4698
4699    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4700        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4701            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4702        } else {
4703            LineIndent::spaces(0)
4704        }
4705    }
4706
4707    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4708        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4709
4710        if self.language_settings(cx).extend_comment_on_newline
4711            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4712        {
4713            let delimiters = language_scope.line_comment_prefixes();
4714            for delimiter in delimiters {
4715                if *self
4716                    .chars_at(Point::new(row.0, indent.len() as u32))
4717                    .take(delimiter.chars().count())
4718                    .collect::<String>()
4719                    .as_str()
4720                    == **delimiter
4721                {
4722                    indent.push_str(delimiter);
4723                    break;
4724                }
4725            }
4726        }
4727
4728        indent
4729    }
4730
4731    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4732    where
4733        T: ToOffset,
4734    {
4735        for char in self.reversed_chars_at(position) {
4736            if !char.is_whitespace() {
4737                return false;
4738            }
4739            if char == '\n' {
4740                return true;
4741            }
4742        }
4743        true
4744    }
4745
4746    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4747        while row.0 > 0 {
4748            row.0 -= 1;
4749            if !self.is_line_blank(row) {
4750                return Some(row);
4751            }
4752        }
4753        None
4754    }
4755
4756    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4757        if let Some((_, range)) = self.buffer_line_for_row(row) {
4758            range.end.column - range.start.column
4759        } else {
4760            0
4761        }
4762    }
4763
4764    pub fn buffer_line_for_row(
4765        &self,
4766        row: MultiBufferRow,
4767    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4768        let mut cursor = self.cursor::<Point, Point>();
4769        let point = Point::new(row.0, 0);
4770        cursor.seek(&point);
4771        let region = cursor.region()?;
4772        let overshoot = point.min(region.range.end) - region.range.start;
4773        let buffer_point = region.buffer_range.start + overshoot;
4774        if buffer_point.row > region.buffer_range.end.row {
4775            return None;
4776        }
4777        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4778        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4779            .min(region.buffer_range.end);
4780        Some((region.buffer, line_start..line_end))
4781    }
4782
4783    pub fn max_point(&self) -> Point {
4784        self.text_summary().lines
4785    }
4786
4787    pub fn max_row(&self) -> MultiBufferRow {
4788        MultiBufferRow(self.text_summary().lines.row)
4789    }
4790
4791    pub fn text_summary(&self) -> MBTextSummary {
4792        self.diff_transforms.summary().output
4793    }
4794
4795    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4796    where
4797        MBD: MultiBufferDimension + AddAssign,
4798        O: ToOffset,
4799    {
4800        let range = range.start.to_offset(self)..range.end.to_offset(self);
4801        let mut cursor = self
4802            .diff_transforms
4803            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4804        cursor.seek(&range.start, Bias::Right);
4805
4806        let Some(first_transform) = cursor.item() else {
4807            return MBD::from_summary(&MBTextSummary::default());
4808        };
4809
4810        let diff_transform_start = cursor.start().0;
4811        let diff_transform_end = cursor.end().0;
4812        let diff_start = range.start;
4813        let start_overshoot = diff_start - diff_transform_start;
4814        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4815
4816        let mut result = match first_transform {
4817            DiffTransform::BufferContent { .. } => {
4818                let excerpt_start = cursor.start().1 + start_overshoot;
4819                let excerpt_end = cursor.start().1 + end_overshoot;
4820                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4821            }
4822            DiffTransform::DeletedHunk {
4823                buffer_id,
4824                base_text_byte_range,
4825                has_trailing_newline,
4826                ..
4827            } => {
4828                let buffer_start = base_text_byte_range.start + start_overshoot;
4829                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4830                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4831                    panic!("{:?} is in non-existent deleted hunk", range.start)
4832                };
4833
4834                let include_trailing_newline =
4835                    *has_trailing_newline && range.end >= diff_transform_end;
4836                if include_trailing_newline {
4837                    buffer_end -= 1;
4838                }
4839
4840                let mut summary = base_text
4841                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4842
4843                if include_trailing_newline {
4844                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4845                        &TextSummary::newline(),
4846                    ))
4847                }
4848
4849                let mut result = MBD::default();
4850                result.add_text_dim(&summary);
4851                result
4852            }
4853        };
4854        if range.end < diff_transform_end {
4855            return result;
4856        }
4857
4858        cursor.next();
4859        result.add_mb_text_summary(
4860            &cursor
4861                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4862                .0,
4863        );
4864
4865        let Some(last_transform) = cursor.item() else {
4866            return result;
4867        };
4868
4869        let overshoot = range.end - cursor.start().0;
4870        let suffix = match last_transform {
4871            DiffTransform::BufferContent { .. } => {
4872                let end = cursor.start().1 + overshoot;
4873                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4874            }
4875            DiffTransform::DeletedHunk {
4876                base_text_byte_range,
4877                buffer_id,
4878                has_trailing_newline,
4879                ..
4880            } => {
4881                let buffer_end = base_text_byte_range.start + overshoot;
4882                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4883                    panic!("{:?} is in non-existent deleted hunk", range.end)
4884                };
4885
4886                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4887                    base_text_byte_range.start..buffer_end,
4888                );
4889                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4890                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4891                        &TextSummary::from("\n"),
4892                    ))
4893                }
4894
4895                let mut result = MBD::default();
4896                result.add_text_dim(&suffix);
4897                result
4898            }
4899        };
4900
4901        result += suffix;
4902        result
4903    }
4904
4905    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4906    where
4907        MBD: MultiBufferDimension + AddAssign,
4908    {
4909        let mut summary = MBD::default();
4910        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4911        cursor.seek(&range.start, Bias::Right);
4912        if let Some(excerpt) = cursor.item() {
4913            let mut end_before_newline = cursor.end();
4914            if excerpt.has_trailing_newline {
4915                end_before_newline -= 1;
4916            }
4917
4918            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4919            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
4920            let end_in_excerpt =
4921                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
4922            summary.add_text_dim(
4923                &excerpt
4924                    .buffer
4925                    .text_summary_for_range::<MBD::TextDimension, _>(
4926                        start_in_excerpt..end_in_excerpt,
4927                    ),
4928            );
4929
4930            if range.end > end_before_newline {
4931                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4932            }
4933
4934            cursor.next();
4935        }
4936
4937        if range.end > *cursor.start() {
4938            summary += cursor
4939                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4940                .0;
4941            if let Some(excerpt) = cursor.item() {
4942                range.end = cmp::max(*cursor.start(), range.end);
4943
4944                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4945                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
4946                summary.add_text_dim(
4947                    &excerpt
4948                        .buffer
4949                        .text_summary_for_range::<MBD::TextDimension, _>(
4950                            excerpt_start..end_in_excerpt,
4951                        ),
4952                );
4953            }
4954        }
4955
4956        summary
4957    }
4958
4959    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4960    where
4961        MBD: MultiBufferDimension
4962            + Ord
4963            + Sub<Output = MBD::TextDimension>
4964            + Sub<MBD::TextDimension, Output = MBD>
4965            + AddAssign<MBD::TextDimension>
4966            + Add<MBD::TextDimension, Output = MBD>,
4967        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4968    {
4969        let target = anchor.seek_target(self);
4970        let anchor = match anchor {
4971            Anchor::Min => {
4972                return MBD::default();
4973            }
4974            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
4975            Anchor::Max => {
4976                return MBD::from_summary(&self.text_summary());
4977            }
4978        };
4979
4980        let (start, _, item) = self
4981            .excerpts
4982            .find::<ExcerptSummary, _>((), &target, Bias::Left);
4983        let start = MBD::from_summary(&start.text);
4984
4985        let excerpt_start_position = ExcerptDimension(start);
4986        if self.diff_transforms.is_empty() {
4987            if let Some(excerpt) = item {
4988                if !excerpt.contains(anchor) {
4989                    return excerpt_start_position.0;
4990                }
4991                let excerpt_buffer_start = excerpt
4992                    .range
4993                    .context
4994                    .start
4995                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4996                let excerpt_buffer_end = excerpt
4997                    .range
4998                    .context
4999                    .end
5000                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5001                let buffer_summary = anchor
5002                    .text_anchor()
5003                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5004                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5005                let mut position = excerpt_start_position;
5006                if summary > excerpt_buffer_start {
5007                    position += summary - excerpt_buffer_start;
5008                }
5009
5010                position.0
5011            } else {
5012                excerpt_start_position.0
5013            }
5014        } else {
5015            let mut diff_transforms_cursor = self
5016                .diff_transforms
5017                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5018            diff_transforms_cursor.next();
5019
5020            if let Some(excerpt) = item {
5021                if !excerpt.contains(anchor) {
5022                    return self.summary_for_excerpt_position_without_hunks(
5023                        Bias::Left,
5024                        excerpt_start_position,
5025                        &mut diff_transforms_cursor,
5026                    );
5027                }
5028                let excerpt_buffer_start = excerpt
5029                    .range
5030                    .context
5031                    .start
5032                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5033                let excerpt_buffer_end = excerpt
5034                    .range
5035                    .context
5036                    .end
5037                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5038                let buffer_summary = anchor
5039                    .text_anchor()
5040                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5041                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5042                let mut position = excerpt_start_position;
5043                if summary > excerpt_buffer_start {
5044                    position += summary - excerpt_buffer_start;
5045                }
5046
5047                if diff_transforms_cursor.start().0 < position {
5048                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5049                }
5050                self.summary_for_anchor_with_excerpt_position(
5051                    *anchor,
5052                    position,
5053                    &mut diff_transforms_cursor,
5054                    &excerpt.buffer,
5055                )
5056            } else {
5057                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5058                self.summary_for_excerpt_position_without_hunks(
5059                    Bias::Right,
5060                    excerpt_start_position,
5061                    &mut diff_transforms_cursor,
5062                )
5063            }
5064        }
5065    }
5066
5067    /// Maps an anchor's excerpt-space position to its output-space position by
5068    /// walking the diff transforms. The cursor is shared across consecutive
5069    /// calls, so it may already be partway through the transform list.
5070    fn summary_for_anchor_with_excerpt_position<MBD>(
5071        &self,
5072        anchor: ExcerptAnchor,
5073        excerpt_position: ExcerptDimension<MBD>,
5074        diff_transforms: &mut Cursor<
5075            DiffTransform,
5076            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5077        >,
5078        excerpt_buffer: &text::BufferSnapshot,
5079    ) -> MBD
5080    where
5081        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5082    {
5083        loop {
5084            let transform_end_position = diff_transforms.end().0;
5085            let item = diff_transforms.item();
5086            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5087
5088            // A right-biased anchor at a transform boundary belongs to the
5089            // *next* transform, so advance past the current one.
5090            if anchor.bias == Bias::Right && at_transform_end {
5091                diff_transforms.next();
5092                continue;
5093            }
5094
5095            let mut position = diff_transforms.start().1;
5096            match item {
5097                Some(DiffTransform::DeletedHunk {
5098                    buffer_id,
5099                    base_text_byte_range,
5100                    hunk_info,
5101                    ..
5102                }) => {
5103                    if let Some(diff_base_anchor) = anchor.diff_base_anchor
5104                        && let Some(base_text) =
5105                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5106                        && diff_base_anchor.is_valid(&base_text)
5107                    {
5108                        // The anchor carries a diff-base position — resolve it
5109                        // to a location inside the deleted hunk.
5110                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5111                        if base_text_offset >= base_text_byte_range.start
5112                            && base_text_offset <= base_text_byte_range.end
5113                        {
5114                            let position_in_hunk = base_text
5115                                .text_summary_for_range::<MBD::TextDimension, _>(
5116                                    base_text_byte_range.start..base_text_offset,
5117                                );
5118                            position.0.add_text_dim(&position_in_hunk);
5119                        } else if at_transform_end {
5120                            // diff_base offset falls outside this hunk's range;
5121                            // advance to see if the next transform is a better fit.
5122                            diff_transforms.next();
5123                            continue;
5124                        }
5125                    } else if at_transform_end
5126                        && anchor
5127                            .text_anchor()
5128                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5129                            .is_gt()
5130                    {
5131                        // The anchor has no (valid) diff-base position, so it
5132                        // belongs in the buffer content, not in the deleted
5133                        // hunk. However, after an edit deletes the text between
5134                        // the hunk boundary and this anchor, both resolve to
5135                        // the same excerpt_position—landing us here on the
5136                        // DeletedHunk left behind by the shared cursor. Use the
5137                        // CRDT ordering to detect that the anchor is strictly
5138                        // *past* the hunk boundary and skip to the following
5139                        // BufferContent.
5140                        diff_transforms.next();
5141                        continue;
5142                    }
5143                }
5144                _ => {
5145                    // On a BufferContent (or no transform). If the anchor
5146                    // carries a diff_base_anchor it needs a DeletedHunk, so
5147                    // advance to find one.
5148                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5149                        diff_transforms.next();
5150                        continue;
5151                    }
5152                    let overshoot = excerpt_position - diff_transforms.start().0;
5153                    position += overshoot;
5154                }
5155            }
5156
5157            return position.0;
5158        }
5159    }
5160
5161    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5162    fn summary_for_excerpt_position_without_hunks<MBD>(
5163        &self,
5164        bias: Bias,
5165        excerpt_position: ExcerptDimension<MBD>,
5166        diff_transforms: &mut Cursor<
5167            DiffTransform,
5168            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5169        >,
5170    ) -> MBD
5171    where
5172        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5173    {
5174        loop {
5175            let transform_end_position = diff_transforms.end().0;
5176            let item = diff_transforms.item();
5177            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5178
5179            // A right-biased anchor at a transform boundary belongs to the
5180            // *next* transform, so advance past the current one.
5181            if bias == Bias::Right && at_transform_end {
5182                diff_transforms.next();
5183                continue;
5184            }
5185
5186            let mut position = diff_transforms.start().1;
5187            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5188                let overshoot = excerpt_position - diff_transforms.start().0;
5189                position += overshoot;
5190            }
5191
5192            return position.0;
5193        }
5194    }
5195
5196    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5197        let anchor = match anchor {
5198            Anchor::Min => return ExcerptOffset::default(),
5199            Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5200            Anchor::Max => return self.excerpts.summary().len(),
5201        };
5202        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5203        let target = anchor.seek_target(self);
5204
5205        cursor.seek(&target, Bias::Left);
5206
5207        let mut position = cursor.start().len();
5208        if let Some(excerpt) = cursor.item()
5209            && excerpt.contains(anchor)
5210        {
5211            let excerpt_buffer_start = excerpt
5212                .buffer
5213                .offset_for_anchor(&excerpt.range.context.start);
5214            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5215            let buffer_position = cmp::min(
5216                excerpt_buffer_end,
5217                excerpt.buffer.offset_for_anchor(&anchor.text_anchor()),
5218            );
5219            if buffer_position > excerpt_buffer_start {
5220                position += buffer_position - excerpt_buffer_start;
5221            }
5222        }
5223        position
5224    }
5225
5226    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5227    where
5228        MBD: MultiBufferDimension
5229            + Ord
5230            + Sub<Output = MBD::TextDimension>
5231            + AddAssign<MBD::TextDimension>,
5232        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5233        I: 'a + IntoIterator<Item = &'a Anchor>,
5234    {
5235        let mut anchors = anchors.into_iter().peekable();
5236        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5237        let mut diff_transforms_cursor = self
5238            .diff_transforms
5239            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5240        diff_transforms_cursor.next();
5241
5242        let mut summaries = Vec::new();
5243        while let Some(anchor) = anchors.peek() {
5244            let target = anchor.seek_target(self);
5245            let excerpt_anchor = match anchor {
5246                Anchor::Min => {
5247                    summaries.push(MBD::default());
5248                    anchors.next();
5249                    continue;
5250                }
5251                Anchor::Excerpt(excerpt_anchor) => excerpt_anchor,
5252                Anchor::Max => {
5253                    summaries.push(MBD::from_summary(&self.text_summary()));
5254                    anchors.next();
5255                    continue;
5256                }
5257            };
5258
5259            cursor.seek_forward(&target, Bias::Left);
5260
5261            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5262            if let Some(excerpt) = cursor.item() {
5263                if !excerpt.contains(&excerpt_anchor) {
5264                    let position = self.summary_for_excerpt_position_without_hunks(
5265                        Bias::Left,
5266                        excerpt_start_position,
5267                        &mut diff_transforms_cursor,
5268                    );
5269                    summaries.push(position);
5270                    anchors.next();
5271                    continue;
5272                }
5273                let excerpt_buffer_start = excerpt
5274                    .range
5275                    .context
5276                    .start
5277                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5278                let excerpt_buffer_end = excerpt
5279                    .range
5280                    .context
5281                    .end
5282                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5283                for (buffer_summary, excerpt_anchor) in excerpt
5284                    .buffer
5285                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5286                        std::iter::from_fn(|| {
5287                            let excerpt_anchor = anchors.peek()?.excerpt_anchor()?;
5288                            if !excerpt.contains(&excerpt_anchor) {
5289                                return None;
5290                            }
5291                            Some((excerpt_anchor.text_anchor(), excerpt_anchor))
5292                        }),
5293                    )
5294                {
5295                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5296                    let mut position = excerpt_start_position;
5297                    if summary > excerpt_buffer_start {
5298                        position += summary - excerpt_buffer_start;
5299                    }
5300
5301                    if diff_transforms_cursor.start().0 < position {
5302                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5303                    }
5304
5305                    summaries.push(self.summary_for_anchor_with_excerpt_position(
5306                        excerpt_anchor,
5307                        position,
5308                        &mut diff_transforms_cursor,
5309                        &excerpt.buffer,
5310                    ));
5311                }
5312            } else {
5313                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5314                let position = self.summary_for_excerpt_position_without_hunks(
5315                    Bias::Right,
5316                    excerpt_start_position,
5317                    &mut diff_transforms_cursor,
5318                );
5319                summaries.push(position);
5320                anchors.next();
5321            }
5322        }
5323
5324        summaries
5325    }
5326
5327    pub fn dimensions_from_points<'a, MBD>(
5328        &'a self,
5329        points: impl 'a + IntoIterator<Item = Point>,
5330    ) -> impl 'a + Iterator<Item = MBD>
5331    where
5332        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5333    {
5334        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5335        cursor.seek(&DimensionPair {
5336            key: Point::default(),
5337            value: None,
5338        });
5339        let mut points = points.into_iter();
5340        iter::from_fn(move || {
5341            let point = points.next()?;
5342
5343            cursor.seek_forward(&DimensionPair {
5344                key: point,
5345                value: None,
5346            });
5347
5348            if let Some(region) = cursor.region() {
5349                let overshoot = point - region.range.start.key;
5350                let buffer_point = region.buffer_range.start + overshoot;
5351                let mut position = region.range.start.value.unwrap();
5352                position.add_text_dim(
5353                    &region
5354                        .buffer
5355                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5356                );
5357                if point == region.range.end.key && region.has_trailing_newline {
5358                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5359                }
5360                Some(position)
5361            } else {
5362                Some(MBD::from_summary(&self.text_summary()))
5363            }
5364        })
5365    }
5366
5367    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5368    where
5369        I: 'a + IntoIterator<Item = &'a Anchor>,
5370    {
5371        let mut anchors = anchors.into_iter().enumerate().peekable();
5372        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5373        cursor.next();
5374
5375        let mut result = Vec::new();
5376
5377        while let Some((_, anchor)) = anchors.peek() {
5378            let old_excerpt_id = anchor.excerpt_id;
5379
5380            // Find the location where this anchor's excerpt should be.
5381            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5382            cursor.seek_forward(&Some(old_locator), Bias::Left);
5383
5384            let next_excerpt = cursor.item();
5385            let prev_excerpt = cursor.prev_item();
5386
5387            // Process all of the anchors for this excerpt.
5388            while let Some((anchor_ix, &anchor)) =
5389                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5390            {
5391                let mut anchor = anchor;
5392
5393                // Leave min and max anchors unchanged if invalid or
5394                // if the old excerpt still exists at this location
5395                let mut kept_position = next_excerpt
5396                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5397                    || old_excerpt_id == ExcerptId::max()
5398                    || old_excerpt_id == ExcerptId::min();
5399
5400                // If the old excerpt no longer exists at this location, then attempt to
5401                // find an equivalent position for this anchor in an adjacent excerpt.
5402                if !kept_position {
5403                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5404                        if excerpt.contains(&anchor) {
5405                            anchor.excerpt_id = excerpt.id;
5406                            kept_position = true;
5407                            break;
5408                        }
5409                    }
5410                }
5411
5412                // If there's no adjacent excerpt that contains the anchor's position,
5413                // then report that the anchor has lost its position.
5414                if !kept_position {
5415                    anchor = if let Some(excerpt) = next_excerpt {
5416                        let mut text_anchor = excerpt
5417                            .range
5418                            .context
5419                            .start
5420                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5421                        if text_anchor
5422                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5423                            .is_gt()
5424                        {
5425                            text_anchor = excerpt.range.context.end;
5426                        }
5427                        Anchor::text(excerpt.id, text_anchor)
5428                    } else if let Some(excerpt) = prev_excerpt {
5429                        let mut text_anchor = excerpt
5430                            .range
5431                            .context
5432                            .end
5433                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5434                        if text_anchor
5435                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5436                            .is_lt()
5437                        {
5438                            text_anchor = excerpt.range.context.start;
5439                        }
5440                        Anchor::text(excerpt.id, text_anchor)
5441                    } else if anchor.text_anchor.bias == Bias::Left {
5442                        Anchor::min()
5443                    } else {
5444                        Anchor::max()
5445                    };
5446                }
5447
5448                result.push((anchor_ix, anchor, kept_position));
5449            }
5450        }
5451        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5452        result
5453    }
5454
5455    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5456        self.anchor_at(position, Bias::Left)
5457    }
5458
5459    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5460        self.anchor_at(position, Bias::Right)
5461    }
5462
5463    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5464        let offset = position.to_offset(self);
5465
5466        // Find the given position in the diff transforms. Determine the corresponding
5467        // offset in the excerpts, and whether the position is within a deleted hunk.
5468        let mut diff_transforms = self
5469            .diff_transforms
5470            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5471        diff_transforms.seek(&offset, Bias::Right);
5472
5473        if offset == diff_transforms.start().0
5474            && bias == Bias::Left
5475            && let Some(prev_item) = diff_transforms.prev_item()
5476            && let DiffTransform::DeletedHunk { .. } = prev_item
5477        {
5478            diff_transforms.prev();
5479        }
5480        let offset_in_transform = offset - diff_transforms.start().0;
5481        let mut excerpt_offset = diff_transforms.start().1;
5482        let mut diff_base_anchor = None;
5483        if let Some(DiffTransform::DeletedHunk {
5484            buffer_id,
5485            base_text_byte_range,
5486            has_trailing_newline,
5487            ..
5488        }) = diff_transforms.item()
5489        {
5490            let diff = self.diffs.get(buffer_id).expect("missing diff");
5491            if offset_in_transform > base_text_byte_range.len() {
5492                debug_assert!(*has_trailing_newline);
5493                bias = Bias::Right;
5494            } else {
5495                diff_base_anchor = Some(
5496                    diff.base_text()
5497                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5498                );
5499                bias = Bias::Left;
5500            }
5501        } else {
5502            excerpt_offset += MultiBufferOffset(offset_in_transform);
5503        };
5504
5505        let mut excerpts = self
5506            .excerpts
5507            .cursor::<Dimensions<ExcerptOffset, ExcerptSummary>>(());
5508        excerpts.seek(&excerpt_offset, Bias::Right);
5509        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5510            excerpts.prev();
5511        }
5512        if let Some(excerpt) = excerpts.item() {
5513            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5514            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5515                overshoot -= 1;
5516                bias = Bias::Right;
5517            }
5518
5519            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5520            let text_anchor =
5521                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5522            let anchor = ExcerptAnchor::in_buffer(excerpt.path_key_index, text_anchor);
5523            let anchor = match diff_base_anchor {
5524                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5525                None => anchor,
5526            };
5527            anchor.into()
5528        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5529        {
5530            Anchor::min()
5531        } else {
5532            Anchor::max()
5533        }
5534    }
5535
5536    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5537    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5538        let (excerpt, buffer, _) = self.as_singleton()?;
5539        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5540            Some(Anchor::in_buffer(excerpt, text_anchor))
5541        } else {
5542            None
5543        }
5544    }
5545
5546    /// Returns an anchor for the given excerpt and text anchor,
5547    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5548    pub fn anchor_range_in_excerpt(
5549        &self,
5550        excerpt_id: ExcerptId,
5551        text_anchor: Range<text::Anchor>,
5552    ) -> Option<Range<Anchor>> {
5553        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5554
5555        Some(
5556            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5557                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5558        )
5559    }
5560
5561    /// Returns an anchor for the given excerpt and text anchor,
5562    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5563    pub fn anchor_in_excerpt(
5564        &self,
5565        excerpt_id: ExcerptId,
5566        text_anchor: text::Anchor,
5567    ) -> Option<Anchor> {
5568        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5569        Self::anchor_in_excerpt_(excerpt, text_anchor)
5570    }
5571
5572    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5573    pub fn anchors_in_excerpt(
5574        &self,
5575        excerpt_id: ExcerptId,
5576        text_anchors: impl IntoIterator<Item = text::Anchor>,
5577    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5578        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5579        Some(
5580            text_anchors
5581                .into_iter()
5582                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5583        )
5584    }
5585
5586    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5587        match text_anchor.buffer_id {
5588            Some(buffer_id) if buffer_id == excerpt.buffer.remote_id() => (),
5589            Some(_) => return None,
5590            None if text_anchor.is_max() || text_anchor.is_min() => {
5591                return Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor));
5592            }
5593            None => return None,
5594        }
5595
5596        let context = &excerpt.range.context;
5597        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5598            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5599        {
5600            return None;
5601        }
5602
5603        Some(Anchor::in_buffer(excerpt.path_key_index, text_anchor))
5604    }
5605
5606    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5607        match anchor {
5608            // todo(lw): should be `!self.is_empty()`
5609            Anchor::Min | Anchor::Max => true,
5610            Anchor::Excerpt(excerpt_anchor) => {
5611                let Some(target) = excerpt_anchor.try_seek_target(self) else {
5612                    return false;
5613                };
5614                let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5615                cursor.seek(&target, Bias::Left);
5616                let Some(excerpt) = cursor.item() else {
5617                    return false;
5618                };
5619                excerpt.buffer.can_resolve(&excerpt_anchor.text_anchor())
5620            }
5621        }
5622    }
5623
5624    pub fn excerpts(
5625        &self,
5626    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5627        self.excerpts
5628            .iter()
5629            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5630    }
5631
5632    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5633    where
5634        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5635        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5636    {
5637        let excerpts = self.excerpts.cursor(());
5638        let diff_transforms = self.diff_transforms.cursor(());
5639        MultiBufferCursor {
5640            excerpts,
5641            diff_transforms,
5642            diffs: &self.diffs,
5643            cached_region: OnceCell::new(),
5644        }
5645    }
5646
5647    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5648        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5649        let mut excerpts = self
5650            .excerpts
5651            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5652        excerpts.seek(&Some(start_locator), Bias::Left);
5653        excerpts.prev();
5654
5655        let mut diff_transforms = self
5656            .diff_transforms
5657            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5658        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5659        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5660            diff_transforms.next();
5661        }
5662
5663        let excerpt = excerpts.item()?;
5664        Some(MultiBufferExcerpt {
5665            excerpt,
5666            offset: diff_transforms.start().output_dimension.0,
5667            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5668            excerpt_offset: excerpts.start().1,
5669            diff_transforms,
5670        })
5671    }
5672
5673    pub fn excerpt_boundaries_in_range<R, T>(
5674        &self,
5675        range: R,
5676    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5677    where
5678        R: RangeBounds<T>,
5679        T: ToOffset,
5680    {
5681        let start_offset;
5682        let start = match range.start_bound() {
5683            Bound::Included(start) => {
5684                start_offset = start.to_offset(self);
5685                Bound::Included(start_offset)
5686            }
5687            Bound::Excluded(_) => {
5688                panic!("not supported")
5689            }
5690            Bound::Unbounded => {
5691                start_offset = MultiBufferOffset::ZERO;
5692                Bound::Unbounded
5693            }
5694        };
5695        let end = match range.end_bound() {
5696            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5697            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5698            Bound::Unbounded => Bound::Unbounded,
5699        };
5700        let bounds = (start, end);
5701        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5702        cursor.seek(&DimensionPair {
5703            key: start_offset,
5704            value: None,
5705        });
5706
5707        if cursor
5708            .fetch_excerpt_with_range()
5709            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5710        {
5711            cursor.prev_excerpt();
5712        } else {
5713            cursor.seek_to_start_of_current_excerpt();
5714        }
5715        let mut prev_region = cursor
5716            .fetch_excerpt_with_range()
5717            .map(|(excerpt, _)| excerpt);
5718
5719        cursor.next_excerpt_forwards();
5720
5721        iter::from_fn(move || {
5722            loop {
5723                if self.singleton {
5724                    return None;
5725                }
5726
5727                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5728                cursor.next_excerpt_forwards();
5729                if !bounds.contains(&next_range.start.key) {
5730                    prev_region = Some(next_excerpt);
5731                    continue;
5732                }
5733
5734                let next_region_start = next_range.start.value.unwrap();
5735                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5736                    range.start.value.unwrap()
5737                } else {
5738                    self.max_point()
5739                };
5740
5741                let prev = prev_region.as_ref().map(|region| ExcerptBoundaryInfo {
5742                    id: region.id,
5743                    buffer: region.buffer.clone(),
5744                    buffer_id: region.buffer_id,
5745                    range: region.range.clone(),
5746                    end_row: MultiBufferRow(next_region_start.row),
5747                });
5748
5749                let next = ExcerptBoundaryInfo {
5750                    id: next_excerpt.id,
5751                    buffer: next_excerpt.buffer.clone(),
5752                    buffer_id: next_excerpt.buffer_id,
5753                    range: next_excerpt.range.clone(),
5754                    end_row: if next_excerpt.has_trailing_newline {
5755                        MultiBufferRow(next_region_end.row - 1)
5756                    } else {
5757                        MultiBufferRow(next_region_end.row)
5758                    },
5759                };
5760
5761                let row = MultiBufferRow(next_region_start.row);
5762
5763                prev_region = Some(next_excerpt);
5764
5765                return Some(ExcerptBoundary { row, prev, next });
5766            }
5767        })
5768    }
5769
5770    pub fn edit_count(&self) -> usize {
5771        self.edit_count
5772    }
5773
5774    pub fn non_text_state_update_count(&self) -> usize {
5775        self.non_text_state_update_count
5776    }
5777
5778    /// Returns the smallest enclosing bracket ranges containing the given range or
5779    /// None if no brackets contain range or the range is not contained in a single
5780    /// excerpt
5781    ///
5782    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5783    #[ztracing::instrument(skip_all)]
5784    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5785        &self,
5786        range: Range<T>,
5787        range_filter: Option<
5788            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5789        >,
5790    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5791        let range = range.start.to_offset(self)..range.end.to_offset(self);
5792        let mut excerpt = self.excerpt_containing(range.clone())?;
5793        let buffer = excerpt.buffer();
5794        let excerpt_buffer_range = excerpt.buffer_range();
5795
5796        // Filter to ranges contained in the excerpt
5797        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5798            excerpt_buffer_range.contains(&BufferOffset(open.start))
5799                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5800                && range_filter.is_none_or(|filter| {
5801                    filter(
5802                        buffer,
5803                        BufferOffset(open.start)..BufferOffset(close.end),
5804                        BufferOffset(close.start)..BufferOffset(close.end),
5805                    )
5806                })
5807        };
5808
5809        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5810            excerpt.map_range_to_buffer(range),
5811            Some(&range_filter),
5812        )?;
5813
5814        Some((
5815            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5816            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5817        ))
5818    }
5819
5820    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5821    /// not contained in a single excerpt
5822    pub fn enclosing_bracket_ranges<T: ToOffset>(
5823        &self,
5824        range: Range<T>,
5825    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5826    {
5827        let range = range.start.to_offset(self)..range.end.to_offset(self);
5828        let mut excerpt = self.excerpt_containing(range.clone())?;
5829
5830        Some(
5831            excerpt
5832                .buffer()
5833                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5834                .filter_map(move |pair| {
5835                    let open_range =
5836                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5837                    let close_range =
5838                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5839                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5840                        Some((
5841                            excerpt.map_range_from_buffer(open_range),
5842                            excerpt.map_range_from_buffer(close_range),
5843                        ))
5844                    } else {
5845                        None
5846                    }
5847                }),
5848        )
5849    }
5850
5851    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5852    /// not contained in a single excerpt
5853    pub fn text_object_ranges<T: ToOffset>(
5854        &self,
5855        range: Range<T>,
5856        options: TreeSitterOptions,
5857    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5858        let range = range.start.to_offset(self)..range.end.to_offset(self);
5859        self.excerpt_containing(range.clone())
5860            .map(|mut excerpt| {
5861                excerpt
5862                    .buffer()
5863                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5864                    .filter_map(move |(range, text_object)| {
5865                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5866                        if excerpt.contains_buffer_range(range.clone()) {
5867                            Some((excerpt.map_range_from_buffer(range), text_object))
5868                        } else {
5869                            None
5870                        }
5871                    })
5872            })
5873            .into_iter()
5874            .flatten()
5875    }
5876
5877    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5878    /// not contained in a single excerpt
5879    pub fn bracket_ranges<T: ToOffset>(
5880        &self,
5881        range: Range<T>,
5882    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5883    {
5884        let range = range.start.to_offset(self)..range.end.to_offset(self);
5885        let mut excerpt = self.excerpt_containing(range.clone())?;
5886        Some(
5887            excerpt
5888                .buffer()
5889                .bracket_ranges(excerpt.map_range_to_buffer(range))
5890                .filter_map(move |pair| {
5891                    let open_range =
5892                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5893                    let close_range =
5894                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5895                    excerpt
5896                        .contains_buffer_range(open_range.start..close_range.end)
5897                        .then(|| BracketMatch {
5898                            open_range: excerpt.map_range_from_buffer(open_range),
5899                            close_range: excerpt.map_range_from_buffer(close_range),
5900                            color_index: pair.color_index,
5901                            newline_only: pair.newline_only,
5902                            syntax_layer_depth: pair.syntax_layer_depth,
5903                        })
5904                })
5905                .map(BracketMatch::bracket_ranges),
5906        )
5907    }
5908
5909    pub fn redacted_ranges<'a, T: ToOffset>(
5910        &'a self,
5911        range: Range<T>,
5912        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5913    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5914        let range = range.start.to_offset(self)..range.end.to_offset(self);
5915        self.lift_buffer_metadata(range, move |buffer, range| {
5916            if redaction_enabled(buffer.file()) {
5917                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5918            } else {
5919                None
5920            }
5921        })
5922        .map(|(range, _, _)| range)
5923    }
5924
5925    pub fn runnable_ranges(
5926        &self,
5927        range: Range<Anchor>,
5928    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5929        let range = range.start.to_offset(self)..range.end.to_offset(self);
5930        self.lift_buffer_metadata(range, move |buffer, range| {
5931            Some(
5932                buffer
5933                    .runnable_ranges(range.clone())
5934                    .filter(move |runnable| {
5935                        runnable.run_range.start >= range.start
5936                            && runnable.run_range.end < range.end
5937                    })
5938                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5939            )
5940        })
5941        .map(|(run_range, runnable, _)| (run_range, runnable))
5942    }
5943
5944    pub fn line_indents(
5945        &self,
5946        start_row: MultiBufferRow,
5947        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5948    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5949        let max_point = self.max_point();
5950        let mut cursor = self.cursor::<Point, Point>();
5951        cursor.seek(&Point::new(start_row.0, 0));
5952        iter::from_fn(move || {
5953            let mut region = cursor.region()?;
5954            while !buffer_filter(&region.excerpt.buffer) {
5955                cursor.next();
5956                region = cursor.region()?;
5957            }
5958            let region = cursor.region()?;
5959            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5960            let buffer_start_row =
5961                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5962
5963            let buffer_end_row = if region.is_main_buffer
5964                && (region.has_trailing_newline || region.range.end == max_point)
5965            {
5966                region.buffer_range.end.row
5967            } else {
5968                region.buffer_range.end.row.saturating_sub(1)
5969            };
5970
5971            let line_indents = region
5972                .buffer
5973                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5974            let region_buffer_row = region.buffer_range.start.row;
5975            let region_row = region.range.start.row;
5976            let region_buffer = &region.excerpt.buffer;
5977            cursor.next();
5978            Some(line_indents.map(move |(buffer_row, indent)| {
5979                let row = region_row + (buffer_row - region_buffer_row);
5980                (MultiBufferRow(row), indent, region_buffer.as_ref())
5981            }))
5982        })
5983        .flatten()
5984    }
5985
5986    pub fn reversed_line_indents(
5987        &self,
5988        end_row: MultiBufferRow,
5989        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5990    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5991        let max_point = self.max_point();
5992        let mut cursor = self.cursor::<Point, Point>();
5993        cursor.seek(&Point::new(end_row.0, 0));
5994        iter::from_fn(move || {
5995            let mut region = cursor.region()?;
5996            while !buffer_filter(&region.excerpt.buffer) {
5997                cursor.prev();
5998                region = cursor.region()?;
5999            }
6000            let region = cursor.region()?;
6001
6002            let buffer_start_row = region.buffer_range.start.row;
6003            let buffer_end_row = if region.is_main_buffer
6004                && (region.has_trailing_newline || region.range.end == max_point)
6005            {
6006                region.buffer_range.end.row + 1
6007            } else {
6008                region.buffer_range.end.row
6009            };
6010
6011            let overshoot = end_row.0 - region.range.start.row;
6012            let buffer_end_row =
6013                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6014
6015            let line_indents = region
6016                .buffer
6017                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6018            let region_buffer_row = region.buffer_range.start.row;
6019            let region_row = region.range.start.row;
6020            let region_buffer = &region.excerpt.buffer;
6021            cursor.prev();
6022            Some(line_indents.map(move |(buffer_row, indent)| {
6023                let row = region_row + (buffer_row - region_buffer_row);
6024                (MultiBufferRow(row), indent, region_buffer.as_ref())
6025            }))
6026        })
6027        .flatten()
6028    }
6029
6030    pub async fn enclosing_indent(
6031        &self,
6032        mut target_row: MultiBufferRow,
6033    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6034        let max_row = MultiBufferRow(self.max_point().row);
6035        if target_row >= max_row {
6036            return None;
6037        }
6038
6039        let mut target_indent = self.line_indent_for_row(target_row);
6040
6041        // If the current row is at the start of an indented block, we want to return this
6042        // block as the enclosing indent.
6043        if !target_indent.is_line_empty() && target_row < max_row {
6044            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6045            if !next_line_indent.is_line_empty()
6046                && target_indent.raw_len() < next_line_indent.raw_len()
6047            {
6048                target_indent = next_line_indent;
6049                target_row.0 += 1;
6050            }
6051        }
6052
6053        const SEARCH_ROW_LIMIT: u32 = 25000;
6054        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6055        const YIELD_INTERVAL: u32 = 100;
6056
6057        let mut accessed_row_counter = 0;
6058
6059        // If there is a blank line at the current row, search for the next non indented lines
6060        if target_indent.is_line_empty() {
6061            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6062            let end =
6063                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6064
6065            let mut non_empty_line_above = None;
6066            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6067                if row < start {
6068                    break;
6069                }
6070                accessed_row_counter += 1;
6071                if accessed_row_counter == YIELD_INTERVAL {
6072                    accessed_row_counter = 0;
6073                    yield_now().await;
6074                }
6075                if !indent.is_line_empty() {
6076                    non_empty_line_above = Some((row, indent));
6077                    break;
6078                }
6079            }
6080
6081            let mut non_empty_line_below = None;
6082            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6083                if row > end {
6084                    break;
6085                }
6086                accessed_row_counter += 1;
6087                if accessed_row_counter == YIELD_INTERVAL {
6088                    accessed_row_counter = 0;
6089                    yield_now().await;
6090                }
6091                if !indent.is_line_empty() {
6092                    non_empty_line_below = Some((row, indent));
6093                    break;
6094                }
6095            }
6096
6097            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6098                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6099                    if above_indent.raw_len() >= below_indent.raw_len() {
6100                        (above_row, above_indent)
6101                    } else {
6102                        (below_row, below_indent)
6103                    }
6104                }
6105                (Some(above), None) => above,
6106                (None, Some(below)) => below,
6107                _ => return None,
6108            };
6109
6110            target_indent = indent;
6111            target_row = row;
6112        }
6113
6114        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6115        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6116
6117        let mut start_indent = None;
6118        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6119            if row < start {
6120                break;
6121            }
6122            accessed_row_counter += 1;
6123            if accessed_row_counter == YIELD_INTERVAL {
6124                accessed_row_counter = 0;
6125                yield_now().await;
6126            }
6127            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6128                start_indent = Some((row, indent));
6129                break;
6130            }
6131        }
6132        let (start_row, start_indent_size) = start_indent?;
6133
6134        let mut end_indent = (end, None);
6135        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6136            if row > end {
6137                break;
6138            }
6139            accessed_row_counter += 1;
6140            if accessed_row_counter == YIELD_INTERVAL {
6141                accessed_row_counter = 0;
6142                yield_now().await;
6143            }
6144            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6145                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6146                break;
6147            }
6148        }
6149        let (end_row, end_indent_size) = end_indent;
6150
6151        let indent = if let Some(end_indent_size) = end_indent_size {
6152            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6153                start_indent_size
6154            } else {
6155                end_indent_size
6156            }
6157        } else {
6158            start_indent_size
6159        };
6160
6161        Some((start_row..end_row, indent))
6162    }
6163
6164    pub fn indent_guides_in_range<T: ToPoint>(
6165        &self,
6166        range: Range<T>,
6167        ignore_disabled_for_language: bool,
6168        cx: &App,
6169    ) -> impl Iterator<Item = IndentGuide> {
6170        let range = range.start.to_point(self)..range.end.to_point(self);
6171        let start_row = MultiBufferRow(range.start.row);
6172        let end_row = MultiBufferRow(range.end.row);
6173
6174        let mut row_indents = self.line_indents(start_row, |buffer| {
6175            let settings =
6176                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6177            settings.indent_guides.enabled || ignore_disabled_for_language
6178        });
6179
6180        let mut result = Vec::new();
6181        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6182
6183        let mut prev_settings = None;
6184        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6185            if first_row > end_row {
6186                break;
6187            }
6188            let current_depth = indent_stack.len() as u32;
6189
6190            // Avoid retrieving the language settings repeatedly for every buffer row.
6191            if let Some((prev_buffer_id, _)) = &prev_settings
6192                && prev_buffer_id != &buffer.remote_id()
6193            {
6194                prev_settings.take();
6195            }
6196            let settings = &prev_settings
6197                .get_or_insert_with(|| {
6198                    (
6199                        buffer.remote_id(),
6200                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6201                    )
6202                })
6203                .1;
6204            let tab_size = settings.tab_size.get();
6205
6206            // When encountering empty, continue until found useful line indent
6207            // then add to the indent stack with the depth found
6208            let mut found_indent = false;
6209            let mut last_row = first_row;
6210            if line_indent.is_line_blank() {
6211                while !found_indent {
6212                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6213                        break;
6214                    };
6215                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6216                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6217                        break;
6218                    }
6219
6220                    if new_line_indent.is_line_blank() {
6221                        continue;
6222                    }
6223                    last_row = target_row.min(end_row);
6224                    line_indent = new_line_indent;
6225                    found_indent = true;
6226                    break;
6227                }
6228            } else {
6229                found_indent = true
6230            }
6231
6232            let depth = if found_indent {
6233                line_indent.len(tab_size) / tab_size
6234            } else {
6235                0
6236            };
6237
6238            match depth.cmp(&current_depth) {
6239                cmp::Ordering::Less => {
6240                    for _ in 0..(current_depth - depth) {
6241                        let mut indent = indent_stack.pop().unwrap();
6242                        if last_row != first_row {
6243                            // In this case, we landed on an empty row, had to seek forward,
6244                            // and discovered that the indent we where on is ending.
6245                            // This means that the last display row must
6246                            // be on line that ends this indent range, so we
6247                            // should display the range up to the first non-empty line
6248                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6249                        }
6250
6251                        result.push(indent)
6252                    }
6253                }
6254                cmp::Ordering::Greater => {
6255                    for next_depth in current_depth..depth {
6256                        indent_stack.push(IndentGuide {
6257                            buffer_id: buffer.remote_id(),
6258                            start_row: first_row,
6259                            end_row: last_row,
6260                            depth: next_depth,
6261                            tab_size,
6262                            settings: settings.indent_guides.clone(),
6263                        });
6264                    }
6265                }
6266                _ => {}
6267            }
6268
6269            for indent in indent_stack.iter_mut() {
6270                indent.end_row = last_row;
6271            }
6272        }
6273
6274        result.extend(indent_stack);
6275        result.into_iter()
6276    }
6277
6278    pub fn trailing_excerpt_update_count(&self) -> usize {
6279        self.trailing_excerpt_update_count
6280    }
6281
6282    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6283        self.point_to_buffer_offset(point)
6284            .and_then(|(buffer, _)| buffer.file())
6285    }
6286
6287    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6288        self.point_to_buffer_offset(offset)
6289            .and_then(|(buffer, offset)| buffer.language_at(offset))
6290    }
6291
6292    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6293        self.excerpts
6294            .first()
6295            .map(|excerpt| &excerpt.buffer)
6296            .map(|buffer| {
6297                language_settings(
6298                    buffer.language().map(|language| language.name()),
6299                    buffer.file(),
6300                    cx,
6301                )
6302            })
6303            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6304    }
6305
6306    pub fn language_settings_at<'a, T: ToOffset>(
6307        &'a self,
6308        point: T,
6309        cx: &'a App,
6310    ) -> Cow<'a, LanguageSettings> {
6311        let mut language = None;
6312        let mut file = None;
6313        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6314            language = buffer.language_at(offset);
6315            file = buffer.file();
6316        }
6317        language_settings(language.map(|l| l.name()), file, cx)
6318    }
6319
6320    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6321        self.point_to_buffer_offset(point)
6322            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6323    }
6324
6325    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6326        self.point_to_buffer_offset(point)
6327            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6328            .unwrap_or_default()
6329    }
6330
6331    pub fn language_indent_size_at<T: ToOffset>(
6332        &self,
6333        position: T,
6334        cx: &App,
6335    ) -> Option<IndentSize> {
6336        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6337        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6338    }
6339
6340    pub fn is_dirty(&self) -> bool {
6341        self.is_dirty
6342    }
6343
6344    pub fn has_deleted_file(&self) -> bool {
6345        self.has_deleted_file
6346    }
6347
6348    pub fn has_conflict(&self) -> bool {
6349        self.has_conflict
6350    }
6351
6352    pub fn has_diagnostics(&self) -> bool {
6353        self.excerpts
6354            .iter()
6355            .any(|excerpt| excerpt.buffer.has_diagnostics())
6356    }
6357
6358    pub fn diagnostic_group(
6359        &self,
6360        buffer_id: BufferId,
6361        group_id: usize,
6362    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6363        self.lift_buffer_metadata::<Point, _, _>(
6364            Point::zero()..self.max_point(),
6365            move |buffer, range| {
6366                if buffer.remote_id() != buffer_id {
6367                    return None;
6368                };
6369                Some(
6370                    buffer
6371                        .diagnostics_in_range(range, false)
6372                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6373                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6374                )
6375            },
6376        )
6377        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6378    }
6379
6380    pub fn diagnostics_in_range<'a, MBD>(
6381        &'a self,
6382        range: Range<MBD>,
6383    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6384    where
6385        MBD::TextDimension: 'a
6386            + text::ToOffset
6387            + text::FromAnchor
6388            + Sub<Output = MBD::TextDimension>
6389            + fmt::Debug
6390            + ops::Add<Output = MBD::TextDimension>
6391            + ops::AddAssign
6392            + Ord,
6393        MBD: MultiBufferDimension
6394            + Ord
6395            + Sub<Output = MBD::TextDimension>
6396            + ops::Add<MBD::TextDimension, Output = MBD>
6397            + ops::AddAssign<MBD::TextDimension>
6398            + 'a,
6399    {
6400        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6401            Some(
6402                buffer
6403                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6404                    .map(|entry| (entry.range, entry.diagnostic)),
6405            )
6406        })
6407        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6408    }
6409
6410    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6411        &'a self,
6412        range: Range<MBD>,
6413    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6414    where
6415        MBD: MultiBufferDimension
6416            + Ord
6417            + Sub<Output = MBD::TextDimension>
6418            + ops::Add<MBD::TextDimension, Output = MBD>
6419            + ops::AddAssign<MBD::TextDimension>,
6420        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6421            + ops::Add<Output = MBD::TextDimension>
6422            + text::ToOffset
6423            + text::FromAnchor
6424            + AddAssign<MBD::TextDimension>
6425            + Ord,
6426    {
6427        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6428            Some(
6429                buffer
6430                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6431                    .map(|entry| (entry.range, entry.diagnostic)),
6432            )
6433        })
6434        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6435    }
6436
6437    pub fn syntax_ancestor<T: ToOffset>(
6438        &self,
6439        range: Range<T>,
6440    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6441        let range = range.start.to_offset(self)..range.end.to_offset(self);
6442        let mut excerpt = self.excerpt_containing(range.clone())?;
6443        let node = excerpt
6444            .buffer()
6445            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6446        let node_range = node.byte_range();
6447        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6448        if !excerpt.contains_buffer_range(node_range.clone()) {
6449            return None;
6450        };
6451        Some((node, excerpt.map_range_from_buffer(node_range)))
6452    }
6453
6454    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6455        let (excerpt_id, _, buffer) = self.as_singleton()?;
6456        let outline = buffer.outline(theme);
6457        Some(Outline::new(
6458            outline
6459                .items
6460                .into_iter()
6461                .flat_map(|item| {
6462                    Some(OutlineItem {
6463                        depth: item.depth,
6464                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6465                        source_range_for_text: self
6466                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6467                        text: item.text,
6468                        highlight_ranges: item.highlight_ranges,
6469                        name_ranges: item.name_ranges,
6470                        body_range: item.body_range.and_then(|body_range| {
6471                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6472                        }),
6473                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6474                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6475                        }),
6476                    })
6477                })
6478                .collect(),
6479        ))
6480    }
6481
6482    pub fn symbols_containing<T: ToOffset>(
6483        &self,
6484        offset: T,
6485        theme: Option<&SyntaxTheme>,
6486    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6487        let anchor = self.anchor_before(offset);
6488        let excerpt @ &Excerpt {
6489            id: excerpt_id,
6490            buffer_id,
6491            ref buffer,
6492            ..
6493        } = self.excerpt(anchor.excerpt_id)?;
6494        if cfg!(debug_assertions) {
6495            match anchor.text_anchor.buffer_id {
6496                // we clearly are hitting this according to sentry, but in what situations can this occur?
6497                Some(anchor_buffer_id) => {
6498                    assert_eq!(
6499                        anchor_buffer_id, buffer_id,
6500                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6501                    )
6502                }
6503                None => assert!(anchor.is_max()),
6504            }
6505        };
6506        Some((
6507            buffer_id,
6508            buffer
6509                .symbols_containing(anchor.text_anchor, theme)
6510                .into_iter()
6511                .flat_map(|item| {
6512                    Some(OutlineItem {
6513                        depth: item.depth,
6514                        source_range_for_text: Anchor::range_in_buffer(
6515                            excerpt_id,
6516                            item.source_range_for_text,
6517                        ),
6518                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6519                        text: item.text,
6520                        highlight_ranges: item.highlight_ranges,
6521                        name_ranges: item.name_ranges,
6522                        body_range: item
6523                            .body_range
6524                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6525                        annotation_range: item
6526                            .annotation_range
6527                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6528                    })
6529                })
6530                .collect(),
6531        ))
6532    }
6533
6534    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6535        self.try_excerpt_locator_for_id(id)
6536            .unwrap_or_else(|| panic!("invalid excerpt id {id:?}"))
6537    }
6538
6539    fn try_excerpt_locator_for_id(&self, id: ExcerptId) -> Option<&Locator> {
6540        if id == ExcerptId::min() {
6541            Some(Locator::min_ref())
6542        } else if id == ExcerptId::max() {
6543            Some(Locator::max_ref())
6544        } else {
6545            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6546            if let Some(entry) = item
6547                && entry.id == id
6548            {
6549                return Some(&entry.locator);
6550            }
6551            None
6552        }
6553    }
6554
6555    pub fn buffer_for_path(&self, path: &PathKey) -> Option<&BufferSnapshot> {
6556        todo!()
6557    }
6558
6559    pub fn path_for_buffer(&self, buffer_id: BufferId) -> Option<&PathKey> {
6560        self.path_keys_by_buffer.get(&buffer_id)
6561    }
6562
6563    pub fn buffer_for_id(&self, id: BufferId) -> Option<&BufferSnapshot> {
6564        self.buffer_for_path(self.path_keys_by_buffer.get(&id)?)
6565    }
6566
6567    fn try_path_for_anchor(&self, anchor: ExcerptAnchor) -> Option<PathKey> {
6568        self.path_keys_by_index.get(&anchor.path).cloned()
6569    }
6570
6571    fn path_for_anchor(&self, anchor: ExcerptAnchor) -> PathKey {
6572        self.try_path_for_anchor(anchor)
6573            .expect("invalid anchor: path was never added to multibuffer")
6574    }
6575
6576    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6577        let mut cursor = self
6578            .excerpts
6579            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6580        let locator = self.excerpt_locator_for_id(excerpt_id);
6581        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6582        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6583            sought_exact = true;
6584            cursor.prev();
6585        } else if excerpt_id == ExcerptId::min() {
6586            sought_exact = true;
6587        }
6588        if sought_exact {
6589            let start = cursor.start().1;
6590            let end = cursor.end().1;
6591            let mut diff_transforms = self
6592                .diff_transforms
6593                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6594            diff_transforms.seek(&start, Bias::Left);
6595            let overshoot = start - diff_transforms.start().0;
6596            let start = diff_transforms.start().1 + overshoot;
6597            diff_transforms.seek(&end, Bias::Right);
6598            let overshoot = end - diff_transforms.start().0;
6599            let end = diff_transforms.start().1 + overshoot;
6600            Some(start.0..end.0)
6601        } else {
6602            None
6603        }
6604    }
6605
6606    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6607    pub fn excerpt_containing<T: ToOffset>(
6608        &self,
6609        range: Range<T>,
6610    ) -> Option<MultiBufferExcerpt<'_>> {
6611        let range = range.start.to_offset(self)..range.end.to_offset(self);
6612        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6613        cursor.seek(&range.start);
6614
6615        let start_excerpt = cursor.excerpt()?;
6616        if range.end != range.start {
6617            cursor.seek_forward(&range.end);
6618            if cursor.excerpt()?.id != start_excerpt.id {
6619                return None;
6620            }
6621        }
6622
6623        cursor.seek_to_start_of_current_excerpt();
6624        let region = cursor.region()?;
6625        let offset = region.range.start;
6626        let buffer_offset = start_excerpt.buffer_start_offset();
6627        let excerpt_offset = *cursor.excerpts.start();
6628        Some(MultiBufferExcerpt {
6629            diff_transforms: cursor.diff_transforms,
6630            excerpt: start_excerpt,
6631            offset,
6632            buffer_offset,
6633            excerpt_offset,
6634        })
6635    }
6636
6637    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6638        match anchor {
6639            Anchor::Min => self
6640                .excerpts
6641                .first()
6642                .map(|excerpt| excerpt.buffer.remote_id()),
6643            Anchor::Excerpt(excerpt_anchor) => Some(excerpt_anchor.buffer_id),
6644            Anchor::Max => self
6645                .excerpts
6646                .last()
6647                .map(|excerpt| excerpt.buffer.remote_id()),
6648        }
6649    }
6650
6651    pub fn selections_in_range<'a>(
6652        &'a self,
6653        range: &'a Range<Anchor>,
6654        include_local: bool,
6655    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6656        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6657        cursor.seek(&range.start.seek_target(self), Bias::Left);
6658        cursor
6659            .take_while(move |excerpt| {
6660                let excerpt_start =
6661                    Anchor::in_buffer(excerpt.path_key_index, excerpt.range.context.start);
6662                excerpt_start.cmp(&range.end, self).is_le()
6663            })
6664            .flat_map(move |excerpt| {
6665                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6666                if let Some(excerpt_anchor) = range.start.excerpt_anchor()
6667                    && excerpt.contains(&excerpt_anchor)
6668                {
6669                    query_range.start = excerpt_anchor.text_anchor();
6670                }
6671                if let Some(excerpt_anchor) = range.end.excerpt_anchor()
6672                    && excerpt.contains(&excerpt_anchor)
6673                {
6674                    query_range.end = excerpt_anchor.text_anchor();
6675                }
6676
6677                excerpt
6678                    .buffer
6679                    .selections_in_range(query_range, include_local)
6680                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6681                        selections.map(move |selection| {
6682                            let mut start =
6683                                Anchor::in_buffer(excerpt.path_key_index, selection.start);
6684                            let mut end = Anchor::in_buffer(excerpt.path_key_index, selection.end);
6685                            if range.start.cmp(&start, self).is_gt() {
6686                                start = range.start;
6687                            }
6688                            if range.end.cmp(&end, self).is_lt() {
6689                                end = range.end;
6690                            }
6691
6692                            (
6693                                replica_id,
6694                                line_mode,
6695                                cursor_shape,
6696                                Selection {
6697                                    id: selection.id,
6698                                    start,
6699                                    end,
6700                                    reversed: selection.reversed,
6701                                    goal: selection.goal,
6702                                },
6703                            )
6704                        })
6705                    })
6706            })
6707    }
6708
6709    pub fn show_headers(&self) -> bool {
6710        self.show_headers
6711    }
6712
6713    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6714        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6715    }
6716
6717    pub fn all_diff_hunks_expanded(&self) -> bool {
6718        self.all_diff_hunks_expanded
6719    }
6720
6721    /// Visually annotates a position or range with the `Debug` representation of a value. The
6722    /// callsite of this function is used as a key - previous annotations will be removed.
6723    #[cfg(debug_assertions)]
6724    #[track_caller]
6725    pub fn debug<V, R>(&self, ranges: &R, value: V)
6726    where
6727        R: debug::ToMultiBufferDebugRanges,
6728        V: std::fmt::Debug,
6729    {
6730        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6731    }
6732
6733    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6734    /// debug annotations with the same key will be removed. The key is also used to determine the
6735    /// annotation's color.
6736    #[cfg(debug_assertions)]
6737    #[track_caller]
6738    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6739    where
6740        K: std::hash::Hash + 'static,
6741        R: debug::ToMultiBufferDebugRanges,
6742        V: std::fmt::Debug,
6743    {
6744        let text_ranges = ranges
6745            .to_multi_buffer_debug_ranges(self)
6746            .into_iter()
6747            .flat_map(|range| {
6748                self.range_to_buffer_ranges(range.start..=range.end)
6749                    .into_iter()
6750                    .map(|(buffer, range, _excerpt_id)| {
6751                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6752                    })
6753            })
6754            .collect();
6755        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6756            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6757        });
6758    }
6759
6760    fn excerpt_edits_for_diff_change(
6761        &self,
6762        path: &PathKey,
6763        diff_change_range: Range<usize>,
6764    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
6765        let mut excerpt_edits = Vec::new();
6766        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6767        cursor.seek(path, Bias::Left);
6768        while let Some(excerpt) = cursor.item()
6769            && &excerpt.path_key == path
6770        {
6771            let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
6772            let excerpt_start = cursor.start().clone();
6773            let excerpt_len = excerpt.text_summary.len;
6774            cursor.next();
6775            if diff_change_range.end < excerpt_buffer_range.start
6776                || diff_change_range.start > excerpt_buffer_range.end
6777            {
6778                continue;
6779            }
6780            let diff_change_start_in_excerpt = diff_change_range
6781                .start
6782                .saturating_sub(excerpt_buffer_range.start);
6783            let diff_change_end_in_excerpt = diff_change_range
6784                .end
6785                .saturating_sub(excerpt_buffer_range.start);
6786            let edit_start = excerpt_start.len() + diff_change_start_in_excerpt.min(excerpt_len);
6787            let edit_end = excerpt_start.len() + diff_change_end_in_excerpt.min(excerpt_len);
6788            excerpt_edits.push(Edit {
6789                old: edit_start..edit_end,
6790                new: edit_start..edit_end,
6791            });
6792        }
6793        excerpt_edits
6794    }
6795
6796    fn excerpt_ranges_for_path(
6797        &self,
6798        path_key: &PathKey,
6799    ) -> impl Iterator<Item = ExcerptRange<text::Anchor>> {
6800        todo!()
6801    }
6802}
6803
6804#[cfg(any(test, feature = "test-support"))]
6805impl MultiBufferSnapshot {
6806    pub fn random_byte_range(
6807        &self,
6808        start_offset: MultiBufferOffset,
6809        rng: &mut impl rand::Rng,
6810    ) -> Range<MultiBufferOffset> {
6811        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6812        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6813        start..end
6814    }
6815
6816    #[cfg(any(test, feature = "test-support"))]
6817    fn check_invariants(&self) {
6818        let excerpts = self.excerpts.items(());
6819        let excerpt_ids = self.excerpt_ids.items(());
6820
6821        for (ix, excerpt) in excerpts.iter().enumerate() {
6822            if ix == 0 {
6823                if excerpt.locator <= Locator::min() {
6824                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6825                }
6826            } else if excerpt.locator <= excerpts[ix - 1].locator {
6827                panic!("excerpts are out-of-order: {:?}", excerpts);
6828            }
6829        }
6830
6831        for (ix, entry) in excerpt_ids.iter().enumerate() {
6832            if ix == 0 {
6833                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6834                    panic!("invalid first excerpt id {:?}", entry.id);
6835                }
6836            } else if entry.id <= excerpt_ids[ix - 1].id {
6837                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6838            }
6839        }
6840
6841        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6842            panic!(
6843                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6844                self.excerpts.summary().text,
6845                self.diff_transforms.summary().input,
6846                self.diff_transforms.items(()),
6847            );
6848        }
6849
6850        let mut prev_transform: Option<&DiffTransform> = None;
6851        for item in self.diff_transforms.iter() {
6852            if let DiffTransform::BufferContent {
6853                summary,
6854                inserted_hunk_info,
6855            } = item
6856            {
6857                if let Some(DiffTransform::BufferContent {
6858                    inserted_hunk_info: prev_inserted_hunk_info,
6859                    ..
6860                }) = prev_transform
6861                    && *inserted_hunk_info == *prev_inserted_hunk_info
6862                {
6863                    panic!(
6864                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6865                        self.diff_transforms.items(())
6866                    );
6867                }
6868                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6869                    panic!("empty buffer content transform");
6870                }
6871            }
6872            prev_transform = Some(item);
6873        }
6874    }
6875}
6876
6877impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6878where
6879    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6880    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6881{
6882    #[instrument(skip_all)]
6883    fn seek(&mut self, position: &MBD) {
6884        let position = OutputDimension(*position);
6885        self.cached_region.take();
6886        self.diff_transforms.seek(&position, Bias::Right);
6887        if self.diff_transforms.item().is_none()
6888            && self.diff_transforms.start().output_dimension == position
6889        {
6890            self.diff_transforms.prev();
6891        }
6892
6893        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6894        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6895            let overshoot = position - self.diff_transforms.start().output_dimension;
6896            excerpt_position += overshoot;
6897        }
6898
6899        self.excerpts.seek(&excerpt_position, Bias::Right);
6900        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6901            self.excerpts.prev();
6902        }
6903    }
6904
6905    fn seek_forward(&mut self, position: &MBD) {
6906        let position = OutputDimension(*position);
6907        self.cached_region.take();
6908        self.diff_transforms.seek_forward(&position, Bias::Right);
6909        if self.diff_transforms.item().is_none()
6910            && self.diff_transforms.start().output_dimension == position
6911        {
6912            self.diff_transforms.prev();
6913        }
6914
6915        let overshoot = position - self.diff_transforms.start().output_dimension;
6916        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6917        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6918            excerpt_position += overshoot;
6919        }
6920
6921        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6922        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6923            self.excerpts.prev();
6924        }
6925    }
6926
6927    fn next_excerpt(&mut self) {
6928        self.excerpts.next();
6929        self.seek_to_start_of_current_excerpt();
6930    }
6931
6932    fn prev_excerpt(&mut self) {
6933        self.excerpts.prev();
6934        self.seek_to_start_of_current_excerpt();
6935    }
6936
6937    fn seek_to_start_of_current_excerpt(&mut self) {
6938        self.cached_region.take();
6939
6940        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
6941            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6942            && self.diff_transforms.next_item().is_some()
6943        {
6944            self.diff_transforms.next();
6945        }
6946    }
6947
6948    fn next_excerpt_forwards(&mut self) {
6949        self.excerpts.next();
6950        self.seek_to_start_of_current_excerpt_forward();
6951    }
6952
6953    fn seek_to_start_of_current_excerpt_forward(&mut self) {
6954        self.cached_region.take();
6955
6956        if self
6957            .diff_transforms
6958            .seek_forward(self.excerpts.start(), Bias::Left)
6959            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6960            && self.diff_transforms.next_item().is_some()
6961        {
6962            self.diff_transforms.next();
6963        }
6964    }
6965
6966    fn next(&mut self) {
6967        self.cached_region.take();
6968        match self
6969            .diff_transforms
6970            .end()
6971            .excerpt_dimension
6972            .cmp(&self.excerpts.end())
6973        {
6974            cmp::Ordering::Less => self.diff_transforms.next(),
6975            cmp::Ordering::Greater => self.excerpts.next(),
6976            cmp::Ordering::Equal => {
6977                self.diff_transforms.next();
6978                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6979                    || self.diff_transforms.item().is_none()
6980                {
6981                    self.excerpts.next();
6982                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6983                    self.diff_transforms.item()
6984                    && self
6985                        .excerpts
6986                        .item()
6987                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6988                {
6989                    self.excerpts.next();
6990                }
6991            }
6992        }
6993    }
6994
6995    fn prev(&mut self) {
6996        self.cached_region.take();
6997        match self
6998            .diff_transforms
6999            .start()
7000            .excerpt_dimension
7001            .cmp(self.excerpts.start())
7002        {
7003            cmp::Ordering::Less => self.excerpts.prev(),
7004            cmp::Ordering::Greater => self.diff_transforms.prev(),
7005            cmp::Ordering::Equal => {
7006                self.diff_transforms.prev();
7007                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7008                    || self.diff_transforms.item().is_none()
7009                {
7010                    self.excerpts.prev();
7011                }
7012            }
7013        }
7014    }
7015
7016    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7017        self.cached_region
7018            .get_or_init(|| self.build_region())
7019            .as_ref()
7020    }
7021
7022    fn is_at_start_of_excerpt(&mut self) -> bool {
7023        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7024            return false;
7025        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7026            return true;
7027        }
7028
7029        self.diff_transforms.prev();
7030        let prev_transform = self.diff_transforms.item();
7031        self.diff_transforms.next();
7032
7033        prev_transform.is_none_or(|next_transform| {
7034            matches!(next_transform, DiffTransform::BufferContent { .. })
7035        })
7036    }
7037
7038    fn is_at_end_of_excerpt(&self) -> bool {
7039        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7040            return false;
7041        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7042            || self.diff_transforms.item().is_none()
7043        {
7044            return true;
7045        }
7046
7047        let next_transform = self.diff_transforms.next_item();
7048        next_transform.is_none_or(|next_transform| match next_transform {
7049            DiffTransform::BufferContent { .. } => true,
7050            DiffTransform::DeletedHunk { hunk_info, .. } => self
7051                .excerpts
7052                .item()
7053                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7054        })
7055    }
7056
7057    fn main_buffer_position(&self) -> Option<BD> {
7058        let excerpt = self.excerpts.item()?;
7059        let buffer = &excerpt.buffer;
7060        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7061        let mut buffer_start = buffer_context_start;
7062        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7063        buffer_start += overshoot;
7064        Some(buffer_start)
7065    }
7066
7067    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7068        let excerpt = self.excerpts.item()?;
7069        match self.diff_transforms.item()? {
7070            DiffTransform::DeletedHunk {
7071                buffer_id,
7072                base_text_byte_range,
7073                has_trailing_newline,
7074                hunk_info,
7075                ..
7076            } => {
7077                let diff = self.diffs.get(buffer_id)?;
7078                let buffer = diff.base_text();
7079                let mut rope_cursor = buffer.as_rope().cursor(0);
7080                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7081                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7082                let mut buffer_end = buffer_start;
7083                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7084                let start = self.diff_transforms.start().output_dimension.0;
7085                let end = self.diff_transforms.end().output_dimension.0;
7086                Some(MultiBufferRegion {
7087                    buffer,
7088                    excerpt,
7089                    has_trailing_newline: *has_trailing_newline,
7090                    is_main_buffer: false,
7091                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7092                        hunk_info.hunk_secondary_status,
7093                    )),
7094                    buffer_range: buffer_start..buffer_end,
7095                    range: start..end,
7096                })
7097            }
7098            DiffTransform::BufferContent {
7099                inserted_hunk_info, ..
7100            } => {
7101                let buffer = &excerpt.buffer;
7102                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7103
7104                let mut start = self.diff_transforms.start().output_dimension.0;
7105                let mut buffer_start = buffer_context_start;
7106                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7107                    let overshoot =
7108                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7109                    start += overshoot;
7110                } else {
7111                    let overshoot =
7112                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7113                    buffer_start += overshoot;
7114                }
7115
7116                let mut end;
7117                let mut buffer_end;
7118                let has_trailing_newline;
7119                let transform_end = self.diff_transforms.end();
7120                if transform_end.excerpt_dimension < self.excerpts.end() {
7121                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7122                    end = transform_end.output_dimension.0;
7123                    buffer_end = buffer_context_start;
7124                    buffer_end += overshoot;
7125                    has_trailing_newline = false;
7126                } else {
7127                    let overshoot =
7128                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7129                    end = self.diff_transforms.start().output_dimension.0;
7130                    end += overshoot;
7131                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7132                    has_trailing_newline = excerpt.has_trailing_newline;
7133                };
7134
7135                let diff_hunk_status = inserted_hunk_info.map(|info| {
7136                    if info.is_logically_deleted {
7137                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7138                    } else {
7139                        DiffHunkStatus::added(info.hunk_secondary_status)
7140                    }
7141                });
7142
7143                Some(MultiBufferRegion {
7144                    buffer,
7145                    excerpt,
7146                    has_trailing_newline,
7147                    is_main_buffer: true,
7148                    diff_hunk_status,
7149                    buffer_range: buffer_start..buffer_end,
7150                    range: start..end,
7151                })
7152            }
7153        }
7154    }
7155
7156    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7157        let excerpt = self.excerpts.item()?;
7158        match self.diff_transforms.item()? {
7159            &DiffTransform::DeletedHunk { .. } => {
7160                let start = self.diff_transforms.start().output_dimension.0;
7161                let end = self.diff_transforms.end().output_dimension.0;
7162                Some((excerpt, start..end))
7163            }
7164            DiffTransform::BufferContent { .. } => {
7165                let mut start = self.diff_transforms.start().output_dimension.0;
7166                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7167                    let overshoot =
7168                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7169                    start += overshoot;
7170                }
7171
7172                let mut end;
7173                let transform_end = self.diff_transforms.end();
7174                if transform_end.excerpt_dimension < self.excerpts.end() {
7175                    end = transform_end.output_dimension.0;
7176                } else {
7177                    let overshoot =
7178                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7179                    end = self.diff_transforms.start().output_dimension.0;
7180                    end += overshoot;
7181                };
7182
7183                Some((excerpt, start..end))
7184            }
7185        }
7186    }
7187
7188    fn excerpt(&self) -> Option<&'a Excerpt> {
7189        self.excerpts.item()
7190    }
7191}
7192
7193impl Excerpt {
7194    fn new(
7195        path_key: PathKey,
7196        buffer: Arc<BufferSnapshot>,
7197        range: ExcerptRange<text::Anchor>,
7198        has_trailing_newline: bool,
7199    ) -> Self {
7200        Excerpt {
7201            path_key,
7202            max_buffer_row: range.context.end.to_point(&buffer).row,
7203            text_summary: buffer
7204                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7205            buffer,
7206            range,
7207            has_trailing_newline,
7208        }
7209    }
7210
7211    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7212        let content_start = self.range.context.start.to_offset(&self.buffer);
7213        let chunks_start = content_start + range.start;
7214        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7215
7216        let has_footer = self.has_trailing_newline
7217            && range.start <= self.text_summary.len
7218            && range.end > self.text_summary.len;
7219
7220        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7221
7222        ExcerptChunks {
7223            content_chunks,
7224            has_footer,
7225        }
7226    }
7227
7228    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7229        let content_start = self.range.context.start.to_offset(&self.buffer);
7230        let chunks_start = content_start + range.start;
7231        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7232        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7233        excerpt_chunks.has_footer = self.has_trailing_newline
7234            && range.start <= self.text_summary.len
7235            && range.end > self.text_summary.len;
7236    }
7237
7238    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7239        if text_anchor
7240            .cmp(&self.range.context.start, &self.buffer)
7241            .is_lt()
7242        {
7243            self.range.context.start
7244        } else if text_anchor
7245            .cmp(&self.range.context.end, &self.buffer)
7246            .is_gt()
7247        {
7248            self.range.context.end
7249        } else {
7250            text_anchor
7251        }
7252    }
7253
7254    pub(crate) fn contains(&self, anchor: &ExcerptAnchor) -> bool {
7255        self.path_key_index == anchor.path
7256            && self.buffer.remote_id() == anchor.buffer_id
7257            && self.range.contains(&anchor.text_anchor(), &self.buffer)
7258    }
7259
7260    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7261    fn buffer_start_offset(&self) -> BufferOffset {
7262        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7263    }
7264
7265    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7266    fn buffer_end_offset(&self) -> BufferOffset {
7267        self.buffer_start_offset() + self.text_summary.len
7268    }
7269}
7270
7271impl PartialEq for Excerpt {
7272    fn eq(&self, other: &Self) -> bool {
7273        self.buffer.remote_id() == other.buffer.remote_id()
7274            && self.range.context == other.range.context
7275    }
7276}
7277
7278impl<'a> MultiBufferExcerpt<'a> {
7279    pub fn id(&self) -> ExcerptId {
7280        self.excerpt.id
7281    }
7282
7283    pub fn buffer_id(&self) -> BufferId {
7284        self.excerpt.buffer_id
7285    }
7286
7287    pub fn start_anchor(&self) -> Anchor {
7288        Anchor::text(self.excerpt.id, self.excerpt.range.context.start)
7289    }
7290
7291    pub fn end_anchor(&self) -> Anchor {
7292        Anchor::text(self.excerpt.id, self.excerpt.range.context.end)
7293    }
7294
7295    pub fn buffer(&self) -> &'a BufferSnapshot {
7296        &self.excerpt.buffer
7297    }
7298
7299    pub fn buffer_range(&self) -> Range<BufferOffset> {
7300        self.buffer_offset
7301            ..BufferOffset(
7302                self.excerpt
7303                    .range
7304                    .context
7305                    .end
7306                    .to_offset(&self.excerpt.buffer.text),
7307            )
7308    }
7309
7310    pub fn start_offset(&self) -> MultiBufferOffset {
7311        self.offset
7312    }
7313
7314    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7315    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7316        self.map_range_to_buffer(offset..offset).start
7317    }
7318
7319    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7320    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7321        self.diff_transforms
7322            .seek(&OutputDimension(range.start), Bias::Right);
7323        let start = self.map_offset_to_buffer_internal(range.start);
7324        let end = if range.end > range.start {
7325            self.diff_transforms
7326                .seek_forward(&OutputDimension(range.end), Bias::Right);
7327            self.map_offset_to_buffer_internal(range.end)
7328        } else {
7329            start
7330        };
7331        start..end
7332    }
7333
7334    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7335        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7336        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7337            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7338        };
7339        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7340        self.buffer_offset + offset_in_excerpt
7341    }
7342
7343    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7344    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7345        self.map_range_from_buffer(buffer_offset..buffer_offset)
7346            .start
7347    }
7348
7349    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7350    pub fn map_range_from_buffer(
7351        &mut self,
7352        buffer_range: Range<BufferOffset>,
7353    ) -> Range<MultiBufferOffset> {
7354        if buffer_range.start < self.buffer_offset {
7355            log::warn!(
7356                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7357            );
7358            return self.offset..self.offset;
7359        }
7360        let overshoot = buffer_range.start - self.buffer_offset;
7361        let excerpt_offset = self.excerpt_offset + overshoot;
7362        let excerpt_seek_dim = excerpt_offset;
7363        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7364        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7365            log::warn!(
7366                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7367            );
7368            return self.offset..self.offset;
7369        }
7370        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7371        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7372
7373        let end = if buffer_range.start < buffer_range.end {
7374            let overshoot = buffer_range.end - self.buffer_offset;
7375            let excerpt_offset = self.excerpt_offset + overshoot;
7376            let excerpt_seek_dim = excerpt_offset;
7377            self.diff_transforms
7378                .seek_forward(&excerpt_seek_dim, Bias::Right);
7379            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7380            // todo(lw): Clamp end to the excerpt boundaries
7381            self.diff_transforms.start().output_dimension.0 + overshoot
7382        } else {
7383            start
7384        };
7385
7386        start..end
7387    }
7388
7389    /// Returns true if the entirety of the given range is in the buffer's excerpt
7390    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7391        range.start >= self.excerpt.buffer_start_offset()
7392            && range.end <= self.excerpt.buffer_end_offset()
7393    }
7394
7395    /// Returns true if any part of the given range is in the buffer's excerpt
7396    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7397        range.start <= self.excerpt.buffer_end_offset()
7398            && range.end >= self.excerpt.buffer_start_offset()
7399    }
7400
7401    pub fn max_buffer_row(&self) -> u32 {
7402        self.excerpt.max_buffer_row
7403    }
7404}
7405
7406impl fmt::Debug for Excerpt {
7407    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7408        f.debug_struct("Excerpt")
7409            .field("path_key", &self.path_key)
7410            .field("range", &self.range)
7411            .field("text_summary", &self.text_summary)
7412            .field("has_trailing_newline", &self.has_trailing_newline)
7413            .finish()
7414    }
7415}
7416
7417impl sum_tree::Item for Excerpt {
7418    type Summary = ExcerptSummary;
7419
7420    fn summary(&self, _cx: ()) -> Self::Summary {
7421        let mut text = self.text_summary;
7422        if self.has_trailing_newline {
7423            text += TextSummary::from("\n");
7424        }
7425        ExcerptSummary {
7426            path_key: self.path_key,
7427            max_anchor: self.range.context.end,
7428            widest_line_number: self.max_buffer_row,
7429            text: text.into(),
7430            count: 1,
7431        }
7432    }
7433}
7434
7435impl DiffTransform {
7436    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7437        match self {
7438            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7439            DiffTransform::BufferContent {
7440                inserted_hunk_info, ..
7441            } => *inserted_hunk_info,
7442        }
7443    }
7444}
7445
7446impl sum_tree::Item for DiffTransform {
7447    type Summary = DiffTransformSummary;
7448
7449    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7450        match self {
7451            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7452                input: *summary,
7453                output: *summary,
7454            },
7455            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7456                input: MBTextSummary::default(),
7457                output: summary.into(),
7458            },
7459        }
7460    }
7461}
7462
7463impl DiffTransformSummary {
7464    fn excerpt_len(&self) -> ExcerptOffset {
7465        ExcerptDimension(self.input.len)
7466    }
7467}
7468
7469impl sum_tree::ContextLessSummary for DiffTransformSummary {
7470    fn zero() -> Self {
7471        DiffTransformSummary {
7472            input: MBTextSummary::default(),
7473            output: MBTextSummary::default(),
7474        }
7475    }
7476
7477    fn add_summary(&mut self, other: &Self) {
7478        self.input += other.input;
7479        self.output += other.output;
7480    }
7481}
7482
7483impl sum_tree::Dimension<'_, ExcerptSummary> for PathKey {
7484    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7485        PathKey::min()
7486    }
7487
7488    fn add_summary(
7489        &mut self,
7490        summary: &'_ ExcerptSummary,
7491        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7492    ) {
7493        *self = summary.path_key.clone();
7494    }
7495}
7496
7497impl sum_tree::Dimension<'_, ExcerptSummary> for MultiBufferOffset {
7498    fn zero(_: <ExcerptSummary as sum_tree::Summary>::Context<'_>) -> Self {
7499        MultiBufferOffset::ZERO
7500    }
7501
7502    fn add_summary(
7503        &mut self,
7504        summary: &'_ ExcerptSummary,
7505        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7506    ) {
7507        self += summary.text.len
7508    }
7509}
7510
7511impl sum_tree::ContextLessSummary for ExcerptSummary {
7512    fn zero() -> Self {
7513        Self::min()
7514    }
7515
7516    fn add_summary(&mut self, summary: &Self) {
7517        debug_assert!(
7518            summary.path_key >= self.path_key,
7519            "Path keys must be in ascending order: {:?} > {:?}",
7520            summary.path_key,
7521            self.path_key
7522        );
7523
7524        self.path_key = summary.path_key.clone();
7525        self.max_anchor = summary.max_anchor;
7526        self.text += summary.text;
7527        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7528        self.count += summary.count;
7529    }
7530}
7531
7532impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for AnchorSeekTarget {
7533    fn cmp(
7534        &self,
7535        cursor_location: &ExcerptSummary,
7536        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7537    ) -> cmp::Ordering {
7538        match self {
7539            AnchorSeekTarget::Min => Ordering::Less,
7540            AnchorSeekTarget::Max => Ordering::Greater,
7541            AnchorSeekTarget::Excerpt {
7542                path_key,
7543                anchor,
7544                snapshot,
7545            } => {
7546                let path_comparison = Ord::cmp(path_key, &cursor_location.path_key);
7547                if path_comparison.is_ne() {
7548                    path_comparison
7549                } else if let Some(snapshot) = snapshot {
7550                    snapshot
7551                        .remote_id()
7552                        .cmp(&cursor_location.buffer_id)
7553                        .then_with(|| {
7554                            anchor
7555                                .text_anchor()
7556                                .cmp(&cursor_location.max_anchor, snapshot)
7557                        })
7558                } else {
7559                    // shouldn't happen because we expect this buffer not to have any excerpts
7560                    // (otherwise snapshot would have been Some)
7561                    Ordering::Equal
7562                }
7563            }
7564        }
7565    }
7566}
7567
7568impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for PathKey {
7569    fn cmp(
7570        &self,
7571        cursor_location: &ExcerptSummary,
7572        _cx: <ExcerptSummary as sum_tree::Summary>::Context<'_>,
7573    ) -> cmp::Ordering {
7574        todo!()
7575    }
7576}
7577
7578impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7579where
7580    MBD: MultiBufferDimension + Default,
7581{
7582    fn zero(_: ()) -> Self {
7583        ExcerptDimension(MBD::default())
7584    }
7585
7586    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7587        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7588    }
7589}
7590
7591#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7592struct OutputDimension<T>(T);
7593
7594impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7595    fn eq(&self, other: &T) -> bool {
7596        self.0 == *other
7597    }
7598}
7599
7600impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7601    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7602        self.0.partial_cmp(other)
7603    }
7604}
7605
7606impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7607where
7608    T: ops::Sub<U, Output = R>,
7609{
7610    type Output = R;
7611
7612    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7613        self.0 - other.0
7614    }
7615}
7616
7617impl<R, T, U> ops::Add<U> for OutputDimension<T>
7618where
7619    T: ops::Add<U, Output = R>,
7620{
7621    type Output = OutputDimension<R>;
7622
7623    fn add(self, other: U) -> Self::Output {
7624        OutputDimension(self.0 + other)
7625    }
7626}
7627
7628impl<T, U> AddAssign<U> for OutputDimension<T>
7629where
7630    T: AddAssign<U>,
7631{
7632    fn add_assign(&mut self, other: U) {
7633        self.0 += other;
7634    }
7635}
7636
7637impl<T, U> SubAssign<U> for OutputDimension<T>
7638where
7639    T: SubAssign<U>,
7640{
7641    fn sub_assign(&mut self, other: U) {
7642        self.0 -= other;
7643    }
7644}
7645
7646#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug, Default)]
7647struct ExcerptDimension<T>(T);
7648
7649impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7650    fn eq(&self, other: &T) -> bool {
7651        self.0 == *other
7652    }
7653}
7654
7655impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7656    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7657        self.0.partial_cmp(other)
7658    }
7659}
7660
7661impl ExcerptOffset {
7662    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7663        self.0.saturating_sub(other.0)
7664    }
7665}
7666
7667impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7668where
7669    T: ops::Sub<U, Output = R>,
7670{
7671    type Output = R;
7672
7673    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7674        self.0 - other.0
7675    }
7676}
7677
7678impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7679where
7680    T: ops::Add<U, Output = R>,
7681{
7682    type Output = ExcerptDimension<R>;
7683
7684    fn add(self, other: U) -> Self::Output {
7685        ExcerptDimension(self.0 + other)
7686    }
7687}
7688
7689impl<T, U> AddAssign<U> for ExcerptDimension<T>
7690where
7691    T: AddAssign<U>,
7692{
7693    fn add_assign(&mut self, other: U) {
7694        self.0 += other;
7695    }
7696}
7697
7698impl<T, U> SubAssign<U> for ExcerptDimension<T>
7699where
7700    T: SubAssign<U>,
7701{
7702    fn sub_assign(&mut self, other: U) {
7703        self.0 -= other;
7704    }
7705}
7706
7707impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7708    fn zero(_: ()) -> Self {
7709        MultiBufferOffset::ZERO
7710    }
7711
7712    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7713        *self += summary.output.len;
7714    }
7715}
7716
7717impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7718    for ExcerptDimension<MBD>
7719where
7720    MBD: MultiBufferDimension + Ord,
7721{
7722    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7723        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7724    }
7725}
7726
7727impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7728    for ExcerptDimension<MBD>
7729where
7730    MBD: MultiBufferDimension + Ord,
7731{
7732    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7733        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7734    }
7735}
7736
7737impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7738    for ExcerptDimension<MBD>
7739{
7740    fn zero(_: ()) -> Self {
7741        ExcerptDimension(MBD::default())
7742    }
7743
7744    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7745        self.0.add_mb_text_summary(&summary.input)
7746    }
7747}
7748
7749impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7750    for OutputDimension<MBD>
7751where
7752    MBD: MultiBufferDimension + Ord,
7753{
7754    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7755        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7756    }
7757}
7758
7759impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7760    for OutputDimension<MBD>
7761{
7762    fn zero(_: ()) -> Self {
7763        OutputDimension(MBD::default())
7764    }
7765
7766    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7767        self.0.add_mb_text_summary(&summary.output)
7768    }
7769}
7770
7771impl MultiBufferRows<'_> {
7772    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7773        self.point = Point::new(row, 0);
7774        self.cursor.seek(&self.point);
7775    }
7776}
7777
7778impl Iterator for MultiBufferRows<'_> {
7779    type Item = RowInfo;
7780
7781    fn next(&mut self) -> Option<Self::Item> {
7782        if self.is_empty && self.point.row == 0 {
7783            self.point += Point::new(1, 0);
7784            return Some(RowInfo {
7785                buffer_id: None,
7786                buffer_row: Some(0),
7787                multibuffer_row: Some(MultiBufferRow(0)),
7788                diff_status: None,
7789                expand_info: None,
7790                wrapped_buffer_row: None,
7791            });
7792        }
7793
7794        let mut region = self.cursor.region()?.clone();
7795        while self.point >= region.range.end {
7796            self.cursor.next();
7797            if let Some(next_region) = self.cursor.region() {
7798                region = next_region.clone();
7799            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7800                let multibuffer_row = MultiBufferRow(self.point.row);
7801                let last_excerpt = self
7802                    .cursor
7803                    .excerpts
7804                    .item()
7805                    .or(self.cursor.excerpts.prev_item())?;
7806                let last_row = last_excerpt
7807                    .range
7808                    .context
7809                    .end
7810                    .to_point(&last_excerpt.buffer)
7811                    .row;
7812
7813                let first_row = last_excerpt
7814                    .range
7815                    .context
7816                    .start
7817                    .to_point(&last_excerpt.buffer)
7818                    .row;
7819
7820                let expand_info = if self.is_singleton {
7821                    None
7822                } else {
7823                    let needs_expand_up = first_row == last_row
7824                        && last_row > 0
7825                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7826                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7827
7828                    if needs_expand_up && needs_expand_down {
7829                        Some(ExpandExcerptDirection::UpAndDown)
7830                    } else if needs_expand_up {
7831                        Some(ExpandExcerptDirection::Up)
7832                    } else if needs_expand_down {
7833                        Some(ExpandExcerptDirection::Down)
7834                    } else {
7835                        None
7836                    }
7837                    .map(|direction| ExpandInfo {
7838                        direction,
7839                        excerpt_id: last_excerpt.id,
7840                    })
7841                };
7842                self.point += Point::new(1, 0);
7843                return Some(RowInfo {
7844                    buffer_id: Some(last_excerpt.buffer_id),
7845                    buffer_row: Some(last_row),
7846                    multibuffer_row: Some(multibuffer_row),
7847                    diff_status: None,
7848                    wrapped_buffer_row: None,
7849                    expand_info,
7850                });
7851            } else {
7852                return None;
7853            };
7854        }
7855
7856        let overshoot = self.point - region.range.start;
7857        let buffer_point = region.buffer_range.start + overshoot;
7858        let expand_info = if self.is_singleton {
7859            None
7860        } else {
7861            let needs_expand_up = self.point.row == region.range.start.row
7862                && self.cursor.is_at_start_of_excerpt()
7863                && buffer_point.row > 0;
7864            let needs_expand_down = (region.excerpt.has_trailing_newline
7865                && self.point.row + 1 == region.range.end.row
7866                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7867                && self.cursor.is_at_end_of_excerpt()
7868                && buffer_point.row < region.buffer.max_point().row;
7869
7870            if needs_expand_up && needs_expand_down {
7871                Some(ExpandExcerptDirection::UpAndDown)
7872            } else if needs_expand_up {
7873                Some(ExpandExcerptDirection::Up)
7874            } else if needs_expand_down {
7875                Some(ExpandExcerptDirection::Down)
7876            } else {
7877                None
7878            }
7879            .map(|direction| ExpandInfo {
7880                direction,
7881                excerpt_id: region.excerpt.id,
7882            })
7883        };
7884
7885        let result = Some(RowInfo {
7886            buffer_id: Some(region.buffer.remote_id()),
7887            buffer_row: Some(buffer_point.row),
7888            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7889            diff_status: region
7890                .diff_hunk_status
7891                .filter(|_| self.point < region.range.end),
7892            expand_info,
7893            wrapped_buffer_row: None,
7894        });
7895        self.point += Point::new(1, 0);
7896        result
7897    }
7898}
7899
7900impl<'a> MultiBufferChunks<'a> {
7901    pub fn offset(&self) -> MultiBufferOffset {
7902        self.range.start
7903    }
7904
7905    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7906        self.diff_transforms.seek(&range.end, Bias::Right);
7907        let mut excerpt_end = self.diff_transforms.start().1;
7908        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7909            let overshoot = range.end - self.diff_transforms.start().0;
7910            excerpt_end += overshoot;
7911        }
7912
7913        self.diff_transforms.seek(&range.start, Bias::Right);
7914        let mut excerpt_start = self.diff_transforms.start().1;
7915        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7916            let overshoot = range.start - self.diff_transforms.start().0;
7917            excerpt_start += overshoot;
7918        }
7919
7920        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7921        self.buffer_chunk.take();
7922        self.range = range;
7923    }
7924
7925    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7926        self.excerpt_offset_range = new_range.clone();
7927        self.excerpts.seek(&new_range.start, Bias::Right);
7928        if let Some(excerpt) = self.excerpts.item() {
7929            let excerpt_start = *self.excerpts.start();
7930            if let Some(excerpt_chunks) = self
7931                .excerpt_chunks
7932                .as_mut()
7933                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7934            {
7935                excerpt.seek_chunks(
7936                    excerpt_chunks,
7937                    (self.excerpt_offset_range.start - excerpt_start)
7938                        ..(self.excerpt_offset_range.end - excerpt_start),
7939                );
7940            } else {
7941                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7942                    (self.excerpt_offset_range.start - excerpt_start)
7943                        ..(self.excerpt_offset_range.end - excerpt_start),
7944                    self.language_aware,
7945                ));
7946            }
7947        } else {
7948            self.excerpt_chunks = None;
7949        }
7950    }
7951
7952    #[ztracing::instrument(skip_all)]
7953    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7954        loop {
7955            if self.excerpt_offset_range.is_empty() {
7956                return None;
7957            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7958                self.excerpt_offset_range.start += chunk.text.len();
7959                return Some(chunk);
7960            } else {
7961                self.excerpts.next();
7962                let excerpt = self.excerpts.item()?;
7963                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7964                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
7965                    self.language_aware,
7966                ));
7967            }
7968        }
7969    }
7970}
7971
7972impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7973    type Item = &'a str;
7974
7975    fn next(&mut self) -> Option<Self::Item> {
7976        let mut region = self.cursor.region()?;
7977        if self.offset == region.range.start {
7978            self.cursor.prev();
7979            region = self.cursor.region()?;
7980            let start_overshoot = self.start.saturating_sub(region.range.start);
7981            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7982                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7983            ));
7984        }
7985
7986        if self.offset == region.range.end && region.has_trailing_newline {
7987            self.offset -= 1;
7988            Some("\n")
7989        } else {
7990            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7991            self.offset -= chunk.len();
7992            Some(chunk)
7993        }
7994    }
7995}
7996
7997impl<'a> Iterator for MultiBufferChunks<'a> {
7998    type Item = Chunk<'a>;
7999
8000    #[ztracing::instrument(skip_all)]
8001    fn next(&mut self) -> Option<Chunk<'a>> {
8002        if self.range.start >= self.range.end {
8003            return None;
8004        }
8005        if self.range.start == self.diff_transforms.end().0 {
8006            self.diff_transforms.next();
8007        }
8008
8009        let diff_transform_start = self.diff_transforms.start().0;
8010        let diff_transform_end = self.diff_transforms.end().0;
8011        debug_assert!(
8012            self.range.start < diff_transform_end,
8013            "{:?} < {:?} of ({1:?}..{2:?})",
8014            self.range.start,
8015            diff_transform_end,
8016            diff_transform_start
8017        );
8018
8019        let diff_transform = self.diff_transforms.item()?;
8020        match diff_transform {
8021            DiffTransform::BufferContent { .. } => {
8022                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8023                    chunk
8024                } else {
8025                    let chunk = self.next_excerpt_chunk().unwrap();
8026                    self.buffer_chunk.insert(chunk)
8027                };
8028
8029                let chunk_end = self.range.start + chunk.text.len();
8030                let diff_transform_end = diff_transform_end.min(self.range.end);
8031
8032                if diff_transform_end < chunk_end {
8033                    let split_idx = diff_transform_end - self.range.start;
8034                    let (before, after) = chunk.text.split_at(split_idx);
8035                    self.range.start = diff_transform_end;
8036                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8037                    let chars = chunk.chars & mask;
8038                    let tabs = chunk.tabs & mask;
8039                    let newlines = chunk.newlines & mask;
8040
8041                    chunk.text = after;
8042                    chunk.chars = chunk.chars >> split_idx;
8043                    chunk.tabs = chunk.tabs >> split_idx;
8044                    chunk.newlines = chunk.newlines >> split_idx;
8045
8046                    Some(Chunk {
8047                        text: before,
8048                        chars,
8049                        tabs,
8050                        newlines,
8051                        ..chunk.clone()
8052                    })
8053                } else {
8054                    self.range.start = chunk_end;
8055                    self.buffer_chunk.take()
8056                }
8057            }
8058            DiffTransform::DeletedHunk {
8059                buffer_id,
8060                base_text_byte_range,
8061                has_trailing_newline,
8062                ..
8063            } => {
8064                let base_text_start =
8065                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8066                let base_text_end =
8067                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8068                let base_text_end = base_text_end.min(base_text_byte_range.end);
8069
8070                let mut chunks = if let Some((_, mut chunks)) = self
8071                    .diff_base_chunks
8072                    .take()
8073                    .filter(|(id, _)| id == buffer_id)
8074                {
8075                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8076                    {
8077                        chunks.seek(base_text_start..base_text_end);
8078                    }
8079                    chunks
8080                } else {
8081                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8082                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8083                };
8084
8085                let chunk = if let Some(chunk) = chunks.next() {
8086                    self.range.start += chunk.text.len();
8087                    self.diff_base_chunks = Some((*buffer_id, chunks));
8088                    chunk
8089                } else {
8090                    debug_assert!(has_trailing_newline);
8091                    self.range.start += "\n".len();
8092                    Chunk {
8093                        text: "\n",
8094                        chars: 1u128,
8095                        newlines: 1u128,
8096                        ..Default::default()
8097                    }
8098                };
8099                Some(chunk)
8100            }
8101        }
8102    }
8103}
8104
8105impl MultiBufferBytes<'_> {
8106    fn consume(&mut self, len: usize) {
8107        self.range.start += len;
8108        self.chunk = &self.chunk[len..];
8109
8110        if !self.range.is_empty() && self.chunk.is_empty() {
8111            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8112                self.chunk = chunk;
8113            } else if self.has_trailing_newline {
8114                self.has_trailing_newline = false;
8115                self.chunk = b"\n";
8116            } else {
8117                self.cursor.next();
8118                if let Some(region) = self.cursor.region() {
8119                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8120                        region.buffer_range.start
8121                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8122                                .min(region.buffer_range.end),
8123                    );
8124                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8125                    self.excerpt_bytes = Some(excerpt_bytes);
8126                    self.has_trailing_newline =
8127                        region.has_trailing_newline && self.range.end >= region.range.end;
8128                    if self.chunk.is_empty() && self.has_trailing_newline {
8129                        self.has_trailing_newline = false;
8130                        self.chunk = b"\n";
8131                    }
8132                }
8133            }
8134        }
8135    }
8136}
8137
8138impl<'a> Iterator for MultiBufferBytes<'a> {
8139    type Item = &'a [u8];
8140
8141    fn next(&mut self) -> Option<Self::Item> {
8142        let chunk = self.chunk;
8143        if chunk.is_empty() {
8144            None
8145        } else {
8146            self.consume(chunk.len());
8147            Some(chunk)
8148        }
8149    }
8150}
8151
8152impl io::Read for MultiBufferBytes<'_> {
8153    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8154        let len = cmp::min(buf.len(), self.chunk.len());
8155        buf[..len].copy_from_slice(&self.chunk[..len]);
8156        if len > 0 {
8157            self.consume(len);
8158        }
8159        Ok(len)
8160    }
8161}
8162
8163impl io::Read for ReversedMultiBufferBytes<'_> {
8164    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8165        let len = cmp::min(buf.len(), self.chunk.len());
8166        buf[..len].copy_from_slice(&self.chunk[..len]);
8167        buf[..len].reverse();
8168        if len > 0 {
8169            self.range.end -= len;
8170            self.chunk = &self.chunk[..self.chunk.len() - len];
8171            if !self.range.is_empty()
8172                && self.chunk.is_empty()
8173                && let Some(chunk) = self.chunks.next()
8174            {
8175                self.chunk = chunk.as_bytes();
8176            }
8177        }
8178        Ok(len)
8179    }
8180}
8181
8182impl<'a> Iterator for ExcerptChunks<'a> {
8183    type Item = Chunk<'a>;
8184
8185    fn next(&mut self) -> Option<Self::Item> {
8186        if let Some(chunk) = self.content_chunks.next() {
8187            return Some(chunk);
8188        }
8189
8190        if self.has_footer {
8191            let text = "\n";
8192            let chars = 0b1;
8193            let newlines = 0b1;
8194            self.has_footer = false;
8195            return Some(Chunk {
8196                text,
8197                chars,
8198                newlines,
8199                ..Default::default()
8200            });
8201        }
8202
8203        None
8204    }
8205}
8206
8207impl ToOffset for Point {
8208    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8209        snapshot.point_to_offset(*self)
8210    }
8211    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8212        snapshot.point_to_offset_utf16(*self)
8213    }
8214}
8215
8216impl ToOffset for MultiBufferOffset {
8217    #[track_caller]
8218    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8219        assert!(
8220            *self <= snapshot.len(),
8221            "offset {} is greater than the snapshot.len() {}",
8222            self.0,
8223            snapshot.len().0,
8224        );
8225        *self
8226    }
8227    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8228        snapshot.offset_to_offset_utf16(*self)
8229    }
8230}
8231
8232impl ToOffset for MultiBufferOffsetUtf16 {
8233    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8234        snapshot.offset_utf16_to_offset(*self)
8235    }
8236
8237    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8238        *self
8239    }
8240}
8241
8242impl ToOffset for PointUtf16 {
8243    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8244        snapshot.point_utf16_to_offset(*self)
8245    }
8246    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8247        snapshot.point_utf16_to_offset_utf16(*self)
8248    }
8249}
8250
8251impl ToPoint for MultiBufferOffset {
8252    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8253        snapshot.offset_to_point(*self)
8254    }
8255    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8256        snapshot.offset_to_point_utf16(*self)
8257    }
8258}
8259
8260impl ToPoint for Point {
8261    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8262        *self
8263    }
8264    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8265        snapshot.point_to_point_utf16(*self)
8266    }
8267}
8268
8269impl ToPoint for PointUtf16 {
8270    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8271        snapshot.point_utf16_to_point(*self)
8272    }
8273    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8274        *self
8275    }
8276}
8277
8278#[cfg(debug_assertions)]
8279pub mod debug {
8280    use super::*;
8281
8282    pub trait ToMultiBufferDebugRanges {
8283        fn to_multi_buffer_debug_ranges(
8284            &self,
8285            snapshot: &MultiBufferSnapshot,
8286        ) -> Vec<Range<MultiBufferOffset>>;
8287    }
8288
8289    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8290        fn to_multi_buffer_debug_ranges(
8291            &self,
8292            snapshot: &MultiBufferSnapshot,
8293        ) -> Vec<Range<MultiBufferOffset>> {
8294            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8295        }
8296    }
8297
8298    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8299        fn to_multi_buffer_debug_ranges(
8300            &self,
8301            snapshot: &MultiBufferSnapshot,
8302        ) -> Vec<Range<MultiBufferOffset>> {
8303            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8304                .to_multi_buffer_debug_ranges(snapshot)
8305        }
8306    }
8307
8308    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8309        fn to_multi_buffer_debug_ranges(
8310            &self,
8311            snapshot: &MultiBufferSnapshot,
8312        ) -> Vec<Range<MultiBufferOffset>> {
8313            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8314        }
8315    }
8316
8317    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8318        fn to_multi_buffer_debug_ranges(
8319            &self,
8320            snapshot: &MultiBufferSnapshot,
8321        ) -> Vec<Range<MultiBufferOffset>> {
8322            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8323        }
8324    }
8325
8326    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8327        fn to_multi_buffer_debug_ranges(
8328            &self,
8329            snapshot: &MultiBufferSnapshot,
8330        ) -> Vec<Range<MultiBufferOffset>> {
8331            self.iter()
8332                .map(|item| {
8333                    let offset = item.to_offset(snapshot);
8334                    offset..offset
8335                })
8336                .collect()
8337        }
8338    }
8339
8340    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8341        fn to_multi_buffer_debug_ranges(
8342            &self,
8343            snapshot: &MultiBufferSnapshot,
8344        ) -> Vec<Range<MultiBufferOffset>> {
8345            self.iter()
8346                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8347                .collect()
8348        }
8349    }
8350}