multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58use ztracing::instrument;
  59
  60pub use self::path_key::{PathExcerptInsertResult, PathKey};
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  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 path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 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 excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 519    excerpts: Vec<Locator>,
 520    _subscriptions: [gpui::Subscription; 2],
 521}
 522
 523struct DiffState {
 524    diff: Entity<BufferDiff>,
 525    is_inverted: bool,
 526    _subscription: gpui::Subscription,
 527}
 528
 529impl DiffState {
 530    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 531        DiffStateSnapshot {
 532            diff: self.diff.read(cx).snapshot(cx),
 533            is_inverted: self.is_inverted,
 534        }
 535    }
 536}
 537
 538#[derive(Clone)]
 539struct DiffStateSnapshot {
 540    diff: BufferDiffSnapshot,
 541    is_inverted: bool,
 542}
 543
 544impl std::ops::Deref for DiffStateSnapshot {
 545    type Target = BufferDiffSnapshot;
 546
 547    fn deref(&self) -> &Self::Target {
 548        &self.diff
 549    }
 550}
 551
 552impl DiffState {
 553    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 554        DiffState {
 555            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 556                BufferDiffEvent::DiffChanged(DiffChanged {
 557                    changed_range,
 558                    base_text_changed_range: _,
 559                    extended_range,
 560                }) => {
 561                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 562                    let range = if use_extended {
 563                        extended_range.clone()
 564                    } else {
 565                        changed_range.clone()
 566                    };
 567                    if let Some(range) = range {
 568                        this.buffer_diff_changed(diff, range, cx)
 569                    }
 570                    cx.emit(Event::BufferDiffChanged);
 571                }
 572                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 573                _ => {}
 574            }),
 575            diff,
 576            is_inverted: false,
 577        }
 578    }
 579
 580    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 581        DiffState {
 582            _subscription: cx.subscribe(&diff, {
 583                move |this, diff, event, cx| match event {
 584                    BufferDiffEvent::DiffChanged(DiffChanged {
 585                        changed_range: _,
 586                        base_text_changed_range,
 587                        extended_range: _,
 588                    }) => {
 589                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 590                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 591                        }
 592                        cx.emit(Event::BufferDiffChanged);
 593                    }
 594                    BufferDiffEvent::LanguageChanged => {
 595                        this.inverted_buffer_diff_language_changed(diff, cx)
 596                    }
 597                    _ => {}
 598                }
 599            }),
 600            diff,
 601            is_inverted: true,
 602        }
 603    }
 604}
 605
 606/// The contents of a [`MultiBuffer`] at a single point in time.
 607#[derive(Clone, Default)]
 608pub struct MultiBufferSnapshot {
 609    excerpts: SumTree<Excerpt>,
 610    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 611    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 612    diff_transforms: SumTree<DiffTransform>,
 613    excerpt_ids: SumTree<ExcerptIdMapping>,
 614    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 615    non_text_state_update_count: usize,
 616    edit_count: usize,
 617    is_dirty: bool,
 618    has_deleted_file: bool,
 619    has_conflict: bool,
 620    has_inverted_diff: bool,
 621    singleton: bool,
 622    trailing_excerpt_update_count: usize,
 623    all_diff_hunks_expanded: bool,
 624    show_deleted_hunks: bool,
 625    use_extended_diff_range: bool,
 626    show_headers: bool,
 627}
 628
 629// follower: None
 630// - BufferContent(Some)
 631// - BufferContent(None)
 632// - DeletedHunk
 633//
 634// follower: Some
 635// - BufferContent(Some)
 636// - BufferContent(None)
 637
 638#[derive(Debug, Clone)]
 639enum DiffTransform {
 640    // RealText
 641    BufferContent {
 642        summary: MBTextSummary,
 643        // modified_hunk_info
 644        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 645    },
 646    // ExpandedHunkText
 647    DeletedHunk {
 648        summary: TextSummary,
 649        buffer_id: BufferId,
 650        hunk_info: DiffTransformHunkInfo,
 651        base_text_byte_range: Range<usize>,
 652        has_trailing_newline: bool,
 653    },
 654}
 655
 656#[derive(Clone, Copy, Debug)]
 657struct DiffTransformHunkInfo {
 658    excerpt_id: ExcerptId,
 659    hunk_start_anchor: text::Anchor,
 660    hunk_secondary_status: DiffHunkSecondaryStatus,
 661    is_logically_deleted: bool,
 662}
 663
 664impl Eq for DiffTransformHunkInfo {}
 665
 666impl PartialEq for DiffTransformHunkInfo {
 667    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 668        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 669    }
 670}
 671
 672impl std::hash::Hash for DiffTransformHunkInfo {
 673    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 674        self.excerpt_id.hash(state);
 675        self.hunk_start_anchor.hash(state);
 676    }
 677}
 678
 679#[derive(Clone)]
 680pub struct ExcerptInfo {
 681    pub id: ExcerptId,
 682    pub buffer: Arc<BufferSnapshot>,
 683    pub buffer_id: BufferId,
 684    pub range: ExcerptRange<text::Anchor>,
 685    pub end_row: MultiBufferRow,
 686}
 687
 688impl std::fmt::Debug for ExcerptInfo {
 689    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 690        f.debug_struct(type_name::<Self>())
 691            .field("id", &self.id)
 692            .field("buffer_id", &self.buffer_id)
 693            .field("path", &self.buffer.file().map(|f| f.path()))
 694            .field("range", &self.range)
 695            .finish()
 696    }
 697}
 698
 699/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 700#[derive(Debug)]
 701pub struct ExcerptBoundary {
 702    pub prev: Option<ExcerptInfo>,
 703    pub next: ExcerptInfo,
 704    /// The row in the `MultiBuffer` where the boundary is located
 705    pub row: MultiBufferRow,
 706}
 707
 708impl ExcerptBoundary {
 709    pub fn starts_new_buffer(&self) -> bool {
 710        match (self.prev.as_ref(), &self.next) {
 711            (None, _) => true,
 712            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 713        }
 714    }
 715}
 716
 717#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 718pub struct ExpandInfo {
 719    pub direction: ExpandExcerptDirection,
 720    pub excerpt_id: ExcerptId,
 721}
 722
 723#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 724pub struct RowInfo {
 725    pub buffer_id: Option<BufferId>,
 726    pub buffer_row: Option<u32>,
 727    pub multibuffer_row: Option<MultiBufferRow>,
 728    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 729    pub expand_info: Option<ExpandInfo>,
 730    pub wrapped_buffer_row: Option<u32>,
 731}
 732
 733/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 734#[derive(Clone)]
 735struct Excerpt {
 736    /// The unique identifier for this excerpt
 737    id: ExcerptId,
 738    /// The location of the excerpt in the [`MultiBuffer`]
 739    locator: Locator,
 740    /// The buffer being excerpted
 741    buffer_id: BufferId,
 742    /// A snapshot of the buffer being excerpted
 743    buffer: Arc<BufferSnapshot>,
 744    /// The range of the buffer to be shown in the excerpt
 745    range: ExcerptRange<text::Anchor>,
 746    /// The last row in the excerpted slice of the buffer
 747    max_buffer_row: BufferRow,
 748    /// A summary of the text in the excerpt
 749    text_summary: TextSummary,
 750    has_trailing_newline: bool,
 751}
 752
 753/// A public view into an `Excerpt` in a [`MultiBuffer`].
 754///
 755/// Contains methods for getting the [`Buffer`] of the excerpt,
 756/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 757#[derive(Clone)]
 758pub struct MultiBufferExcerpt<'a> {
 759    excerpt: &'a Excerpt,
 760    diff_transforms:
 761        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 762    /// The offset in the multibuffer considering diff transforms.
 763    offset: MultiBufferOffset,
 764    /// The offset in the multibuffer without diff transforms.
 765    excerpt_offset: ExcerptOffset,
 766    buffer_offset: BufferOffset,
 767}
 768
 769#[derive(Clone, Debug)]
 770struct ExcerptIdMapping {
 771    id: ExcerptId,
 772    locator: Locator,
 773}
 774
 775/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 776/// These ranges are relative to the buffer itself
 777#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 778pub struct ExcerptRange<T> {
 779    /// The full range of text to be shown in the excerpt.
 780    pub context: Range<T>,
 781    /// The primary range of text to be highlighted in the excerpt.
 782    /// In a multi-buffer search, this would be the text that matched the search
 783    pub primary: Range<T>,
 784}
 785
 786impl<T: Clone> ExcerptRange<T> {
 787    pub fn new(context: Range<T>) -> Self {
 788        Self {
 789            context: context.clone(),
 790            primary: context,
 791        }
 792    }
 793}
 794
 795#[derive(Clone, Debug, Default)]
 796pub struct ExcerptSummary {
 797    excerpt_id: ExcerptId,
 798    /// The location of the last [`Excerpt`] being summarized
 799    excerpt_locator: Locator,
 800    widest_line_number: u32,
 801    text: MBTextSummary,
 802}
 803
 804#[derive(Debug, Clone)]
 805pub struct DiffTransformSummary {
 806    input: MBTextSummary,
 807    output: MBTextSummary,
 808}
 809
 810/// Summary of a string of text.
 811#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 812pub struct MBTextSummary {
 813    /// Length in bytes.
 814    pub len: MultiBufferOffset,
 815    /// Length in UTF-8.
 816    pub chars: usize,
 817    /// Length in UTF-16 code units
 818    pub len_utf16: OffsetUtf16,
 819    /// A point representing the number of lines and the length of the last line.
 820    ///
 821    /// In other words, it marks the point after the last byte in the text, (if
 822    /// EOF was a character, this would be its position).
 823    pub lines: Point,
 824    /// How many `char`s are in the first line
 825    pub first_line_chars: u32,
 826    /// How many `char`s are in the last line
 827    pub last_line_chars: u32,
 828    /// How many UTF-16 code units are in the last line
 829    pub last_line_len_utf16: u32,
 830    /// The row idx of the longest row
 831    pub longest_row: u32,
 832    /// How many `char`s are in the longest row
 833    pub longest_row_chars: u32,
 834}
 835
 836impl From<TextSummary> for MBTextSummary {
 837    fn from(summary: TextSummary) -> Self {
 838        MBTextSummary {
 839            len: MultiBufferOffset(summary.len),
 840            chars: summary.chars,
 841            len_utf16: summary.len_utf16,
 842            lines: summary.lines,
 843            first_line_chars: summary.first_line_chars,
 844            last_line_chars: summary.last_line_chars,
 845            last_line_len_utf16: summary.last_line_len_utf16,
 846            longest_row: summary.longest_row,
 847            longest_row_chars: summary.longest_row_chars,
 848        }
 849    }
 850}
 851
 852impl From<MBTextSummary> for TextSummary {
 853    fn from(summary: MBTextSummary) -> Self {
 854        TextSummary {
 855            len: summary.len.0,
 856            chars: summary.chars,
 857            len_utf16: summary.len_utf16,
 858            lines: summary.lines,
 859            first_line_chars: summary.first_line_chars,
 860            last_line_chars: summary.last_line_chars,
 861            last_line_len_utf16: summary.last_line_len_utf16,
 862            longest_row: summary.longest_row,
 863            longest_row_chars: summary.longest_row_chars,
 864        }
 865    }
 866}
 867
 868impl From<&str> for MBTextSummary {
 869    fn from(text: &str) -> Self {
 870        MBTextSummary::from(TextSummary::from(text))
 871    }
 872}
 873
 874impl MultiBufferDimension for MBTextSummary {
 875    type TextDimension = TextSummary;
 876
 877    fn from_summary(summary: &MBTextSummary) -> Self {
 878        *summary
 879    }
 880
 881    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 882        *self += *summary;
 883    }
 884
 885    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 886        *self += *summary;
 887    }
 888}
 889
 890impl AddAssign for MBTextSummary {
 891    fn add_assign(&mut self, other: MBTextSummary) {
 892        let joined_chars = self.last_line_chars + other.first_line_chars;
 893        if joined_chars > self.longest_row_chars {
 894            self.longest_row = self.lines.row;
 895            self.longest_row_chars = joined_chars;
 896        }
 897        if other.longest_row_chars > self.longest_row_chars {
 898            self.longest_row = self.lines.row + other.longest_row;
 899            self.longest_row_chars = other.longest_row_chars;
 900        }
 901
 902        if self.lines.row == 0 {
 903            self.first_line_chars += other.first_line_chars;
 904        }
 905
 906        if other.lines.row == 0 {
 907            self.last_line_chars += other.first_line_chars;
 908            self.last_line_len_utf16 += other.last_line_len_utf16;
 909        } else {
 910            self.last_line_chars = other.last_line_chars;
 911            self.last_line_len_utf16 = other.last_line_len_utf16;
 912        }
 913
 914        self.chars += other.chars;
 915        self.len += other.len;
 916        self.len_utf16 += other.len_utf16;
 917        self.lines += other.lines;
 918    }
 919}
 920
 921impl AddAssign<TextSummary> for MBTextSummary {
 922    fn add_assign(&mut self, other: TextSummary) {
 923        *self += MBTextSummary::from(other);
 924    }
 925}
 926
 927impl MBTextSummary {
 928    pub fn lines_utf16(&self) -> PointUtf16 {
 929        PointUtf16 {
 930            row: self.lines.row,
 931            column: self.last_line_len_utf16,
 932        }
 933    }
 934}
 935
 936impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 937where
 938    K: MultiBufferDimension,
 939    V: MultiBufferDimension,
 940{
 941    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 942
 943    fn from_summary(summary: &MBTextSummary) -> Self {
 944        Self {
 945            key: K::from_summary(summary),
 946            value: Some(V::from_summary(summary)),
 947        }
 948    }
 949
 950    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 951        self.key.add_text_dim(&summary.key);
 952        if let Some(value) = &mut self.value {
 953            if let Some(other_value) = summary.value.as_ref() {
 954                value.add_text_dim(other_value);
 955            }
 956        }
 957    }
 958
 959    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 960        self.key.add_mb_text_summary(summary);
 961        if let Some(value) = &mut self.value {
 962            value.add_mb_text_summary(summary);
 963        }
 964    }
 965}
 966
 967#[derive(Clone)]
 968pub struct MultiBufferRows<'a> {
 969    point: Point,
 970    is_empty: bool,
 971    is_singleton: bool,
 972    cursor: MultiBufferCursor<'a, Point, Point>,
 973}
 974
 975pub struct MultiBufferChunks<'a> {
 976    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 977    diff_transforms:
 978        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 979    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 980    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 981    buffer_chunk: Option<Chunk<'a>>,
 982    range: Range<MultiBufferOffset>,
 983    excerpt_offset_range: Range<ExcerptOffset>,
 984    excerpt_chunks: Option<ExcerptChunks<'a>>,
 985    language_aware: bool,
 986}
 987
 988pub struct ReversedMultiBufferChunks<'a> {
 989    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 990    current_chunks: Option<rope::Chunks<'a>>,
 991    start: MultiBufferOffset,
 992    offset: MultiBufferOffset,
 993}
 994
 995pub struct MultiBufferBytes<'a> {
 996    range: Range<MultiBufferOffset>,
 997    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 998    excerpt_bytes: Option<text::Bytes<'a>>,
 999    has_trailing_newline: bool,
1000    chunk: &'a [u8],
1001}
1002
1003pub struct ReversedMultiBufferBytes<'a> {
1004    range: Range<MultiBufferOffset>,
1005    chunks: ReversedMultiBufferChunks<'a>,
1006    chunk: &'a [u8],
1007}
1008
1009#[derive(Clone)]
1010struct DiffTransforms<MBD> {
1011    output_dimension: OutputDimension<MBD>,
1012    excerpt_dimension: ExcerptDimension<MBD>,
1013}
1014
1015impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1016    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1017        Self {
1018            output_dimension: OutputDimension::zero(cx),
1019            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1020                cx,
1021            ),
1022        }
1023    }
1024
1025    fn add_summary(
1026        &mut self,
1027        summary: &'a DiffTransformSummary,
1028        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1029    ) {
1030        self.output_dimension.add_summary(summary, cx);
1031        self.excerpt_dimension.add_summary(summary, cx);
1032    }
1033}
1034
1035#[derive(Clone)]
1036struct MultiBufferCursor<'a, MBD, BD> {
1037    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1038    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1039    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1040    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1041}
1042
1043#[derive(Clone)]
1044struct MultiBufferRegion<'a, MBD, BD> {
1045    buffer: &'a BufferSnapshot,
1046    is_main_buffer: bool,
1047    diff_hunk_status: Option<DiffHunkStatus>,
1048    excerpt: &'a Excerpt,
1049    buffer_range: Range<BD>,
1050    range: Range<MBD>,
1051    has_trailing_newline: bool,
1052}
1053
1054struct ExcerptChunks<'a> {
1055    excerpt_id: ExcerptId,
1056    content_chunks: BufferChunks<'a>,
1057    has_footer: bool,
1058}
1059
1060#[derive(Debug)]
1061struct BufferEdit {
1062    range: Range<BufferOffset>,
1063    new_text: Arc<str>,
1064    is_insertion: bool,
1065    original_indent_column: Option<u32>,
1066    excerpt_id: ExcerptId,
1067}
1068
1069#[derive(Clone, Copy, Debug, PartialEq)]
1070enum DiffChangeKind {
1071    BufferEdited,
1072    DiffUpdated { base_changed: bool },
1073    ExpandOrCollapseHunks { expand: bool },
1074}
1075
1076#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1077pub enum ExpandExcerptDirection {
1078    Up,
1079    Down,
1080    UpAndDown,
1081}
1082
1083impl ExpandExcerptDirection {
1084    pub fn should_expand_up(&self) -> bool {
1085        match self {
1086            ExpandExcerptDirection::Up => true,
1087            ExpandExcerptDirection::Down => false,
1088            ExpandExcerptDirection::UpAndDown => true,
1089        }
1090    }
1091
1092    pub fn should_expand_down(&self) -> bool {
1093        match self {
1094            ExpandExcerptDirection::Up => false,
1095            ExpandExcerptDirection::Down => true,
1096            ExpandExcerptDirection::UpAndDown => true,
1097        }
1098    }
1099}
1100
1101#[derive(Clone, Debug, PartialEq)]
1102pub struct IndentGuide {
1103    pub buffer_id: BufferId,
1104    pub start_row: MultiBufferRow,
1105    pub end_row: MultiBufferRow,
1106    pub depth: u32,
1107    pub tab_size: u32,
1108    pub settings: IndentGuideSettings,
1109}
1110
1111impl IndentGuide {
1112    pub fn indent_level(&self) -> u32 {
1113        self.depth * self.tab_size
1114    }
1115}
1116
1117impl MultiBuffer {
1118    pub fn new(capability: Capability) -> Self {
1119        Self::new_(
1120            capability,
1121            MultiBufferSnapshot {
1122                show_headers: true,
1123                show_deleted_hunks: true,
1124                ..MultiBufferSnapshot::default()
1125            },
1126        )
1127    }
1128
1129    pub fn without_headers(capability: Capability) -> Self {
1130        Self::new_(
1131            capability,
1132            MultiBufferSnapshot {
1133                show_deleted_hunks: true,
1134                ..MultiBufferSnapshot::default()
1135            },
1136        )
1137    }
1138
1139    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1140        let mut this = Self::new_(
1141            buffer.read(cx).capability(),
1142            MultiBufferSnapshot {
1143                singleton: true,
1144                show_deleted_hunks: true,
1145                ..MultiBufferSnapshot::default()
1146            },
1147        );
1148        this.singleton = true;
1149        let buffer_id = buffer.read(cx).remote_id();
1150        this.push_excerpts(
1151            buffer,
1152            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1153                buffer_id,
1154            ))],
1155            cx,
1156        );
1157        this
1158    }
1159
1160    #[inline]
1161    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1162        Self {
1163            snapshot: RefCell::new(snapshot),
1164            buffers: Default::default(),
1165            diffs: HashMap::default(),
1166            subscriptions: Topic::default(),
1167            singleton: false,
1168            capability,
1169            title: None,
1170            excerpts_by_path: Default::default(),
1171            paths_by_excerpt: Default::default(),
1172            buffer_changed_since_sync: Default::default(),
1173            history: History::default(),
1174        }
1175    }
1176
1177    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1178        let mut buffers = BTreeMap::default();
1179        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1180        for (buffer_id, buffer_state) in self.buffers.iter() {
1181            buffer_state.buffer.update(new_cx, |buffer, _| {
1182                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1183            });
1184            buffers.insert(
1185                *buffer_id,
1186                BufferState {
1187                    buffer: buffer_state.buffer.clone(),
1188                    last_version: buffer_state.last_version.clone(),
1189                    last_non_text_state_update_count: buffer_state
1190                        .last_non_text_state_update_count
1191                        .clone(),
1192                    excerpts: buffer_state.excerpts.clone(),
1193                    _subscriptions: [
1194                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1195                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1196                    ],
1197                },
1198            );
1199        }
1200        let mut diff_bases = HashMap::default();
1201        for (buffer_id, diff) in self.diffs.iter() {
1202            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1203        }
1204        Self {
1205            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1206            buffers,
1207            excerpts_by_path: Default::default(),
1208            paths_by_excerpt: Default::default(),
1209            diffs: diff_bases,
1210            subscriptions: Default::default(),
1211            singleton: self.singleton,
1212            capability: self.capability,
1213            history: self.history.clone(),
1214            title: self.title.clone(),
1215            buffer_changed_since_sync,
1216        }
1217    }
1218
1219    pub fn set_group_interval(&mut self, group_interval: Duration) {
1220        self.history.set_group_interval(group_interval);
1221    }
1222
1223    pub fn with_title(mut self, title: String) -> Self {
1224        self.title = Some(title);
1225        self
1226    }
1227
1228    pub fn read_only(&self) -> bool {
1229        !self.capability.editable()
1230    }
1231
1232    pub fn capability(&self) -> Capability {
1233        self.capability
1234    }
1235
1236    /// Returns an up-to-date snapshot of the MultiBuffer.
1237    #[ztracing::instrument(skip_all)]
1238    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1239        self.sync(cx);
1240        self.snapshot.borrow().clone()
1241    }
1242
1243    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1244        self.sync(cx);
1245        self.snapshot.borrow()
1246    }
1247
1248    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1249        if self.singleton {
1250            Some(self.buffers.values().next().unwrap().buffer.clone())
1251        } else {
1252            None
1253        }
1254    }
1255
1256    pub fn is_singleton(&self) -> bool {
1257        self.singleton
1258    }
1259
1260    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1261        self.subscriptions.subscribe()
1262    }
1263
1264    pub fn is_dirty(&self, cx: &App) -> bool {
1265        self.read(cx).is_dirty()
1266    }
1267
1268    pub fn has_deleted_file(&self, cx: &App) -> bool {
1269        self.read(cx).has_deleted_file()
1270    }
1271
1272    pub fn has_conflict(&self, cx: &App) -> bool {
1273        self.read(cx).has_conflict()
1274    }
1275
1276    // The `is_empty` signature doesn't match what clippy expects
1277    #[allow(clippy::len_without_is_empty)]
1278    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1279        self.read(cx).len()
1280    }
1281
1282    pub fn is_empty(&self) -> bool {
1283        self.buffers.is_empty()
1284    }
1285
1286    pub fn edit<I, S, T>(
1287        &mut self,
1288        edits: I,
1289        autoindent_mode: Option<AutoindentMode>,
1290        cx: &mut Context<Self>,
1291    ) where
1292        I: IntoIterator<Item = (Range<S>, T)>,
1293        S: ToOffset,
1294        T: Into<Arc<str>>,
1295    {
1296        self.edit_internal(edits, autoindent_mode, true, cx);
1297    }
1298
1299    pub fn edit_non_coalesce<I, S, T>(
1300        &mut self,
1301        edits: I,
1302        autoindent_mode: Option<AutoindentMode>,
1303        cx: &mut Context<Self>,
1304    ) where
1305        I: IntoIterator<Item = (Range<S>, T)>,
1306        S: ToOffset,
1307        T: Into<Arc<str>>,
1308    {
1309        self.edit_internal(edits, autoindent_mode, false, cx);
1310    }
1311
1312    fn edit_internal<I, S, T>(
1313        &mut self,
1314        edits: I,
1315        autoindent_mode: Option<AutoindentMode>,
1316        coalesce_adjacent: bool,
1317        cx: &mut Context<Self>,
1318    ) where
1319        I: IntoIterator<Item = (Range<S>, T)>,
1320        S: ToOffset,
1321        T: Into<Arc<str>>,
1322    {
1323        if self.read_only() || self.buffers.is_empty() {
1324            return;
1325        }
1326        self.sync_mut(cx);
1327        let edits = edits
1328            .into_iter()
1329            .map(|(range, new_text)| {
1330                let mut range = range.start.to_offset(self.snapshot.get_mut())
1331                    ..range.end.to_offset(self.snapshot.get_mut());
1332                if range.start > range.end {
1333                    mem::swap(&mut range.start, &mut range.end);
1334                }
1335                (range, new_text.into())
1336            })
1337            .collect::<Vec<_>>();
1338
1339        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1340
1341        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1342        fn edit_internal(
1343            this: &mut MultiBuffer,
1344            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1345            mut autoindent_mode: Option<AutoindentMode>,
1346            coalesce_adjacent: bool,
1347            cx: &mut Context<MultiBuffer>,
1348        ) {
1349            let original_indent_columns = match &mut autoindent_mode {
1350                Some(AutoindentMode::Block {
1351                    original_indent_columns,
1352                }) => mem::take(original_indent_columns),
1353                _ => Default::default(),
1354            };
1355
1356            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1357                edits,
1358                this.snapshot.get_mut(),
1359                &original_indent_columns,
1360            );
1361
1362            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1363            for (buffer_id, mut edits) in buffer_edits {
1364                buffer_ids.push(buffer_id);
1365                edits.sort_by_key(|edit| edit.range.start);
1366                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1367                    let mut edits = edits.into_iter().peekable();
1368                    let mut insertions = Vec::new();
1369                    let mut original_indent_columns = Vec::new();
1370                    let mut deletions = Vec::new();
1371                    let empty_str: Arc<str> = Arc::default();
1372                    while let Some(BufferEdit {
1373                        mut range,
1374                        mut new_text,
1375                        mut is_insertion,
1376                        original_indent_column,
1377                        excerpt_id,
1378                    }) = edits.next()
1379                    {
1380                        while let Some(BufferEdit {
1381                            range: next_range,
1382                            is_insertion: next_is_insertion,
1383                            new_text: next_new_text,
1384                            excerpt_id: next_excerpt_id,
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                                if excerpt_id == *next_excerpt_id {
1398                                    new_text = format!("{new_text}{next_new_text}").into();
1399                                }
1400                                edits.next();
1401                            } else {
1402                                break;
1403                            }
1404                        }
1405
1406                        if is_insertion {
1407                            original_indent_columns.push(original_indent_column);
1408                            insertions.push((
1409                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1410                                new_text.clone(),
1411                            ));
1412                        } else if !range.is_empty() {
1413                            deletions.push((
1414                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1415                                empty_str.clone(),
1416                            ));
1417                        }
1418                    }
1419
1420                    let deletion_autoindent_mode =
1421                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1422                            Some(AutoindentMode::Block {
1423                                original_indent_columns: Default::default(),
1424                            })
1425                        } else {
1426                            autoindent_mode.clone()
1427                        };
1428                    let insertion_autoindent_mode =
1429                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1430                            Some(AutoindentMode::Block {
1431                                original_indent_columns,
1432                            })
1433                        } else {
1434                            autoindent_mode.clone()
1435                        };
1436
1437                    if coalesce_adjacent {
1438                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1439                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1440                    } else {
1441                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1442                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1443                    }
1444                })
1445            }
1446
1447            cx.emit(Event::ExcerptsEdited {
1448                excerpt_ids: edited_excerpt_ids,
1449                buffer_ids,
1450            });
1451        }
1452    }
1453
1454    fn convert_edits_to_buffer_edits(
1455        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1456        snapshot: &MultiBufferSnapshot,
1457        original_indent_columns: &[Option<u32>],
1458    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1459        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1460        let mut edited_excerpt_ids = Vec::new();
1461        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1462        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1463            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1464
1465            cursor.seek(&range.start);
1466            let mut start_region = cursor.region().expect("start offset out of bounds");
1467            if !start_region.is_main_buffer {
1468                cursor.next();
1469                if let Some(region) = cursor.region() {
1470                    start_region = region;
1471                } else {
1472                    continue;
1473                }
1474            }
1475
1476            if range.end < start_region.range.start {
1477                continue;
1478            }
1479
1480            let start_region = start_region.clone();
1481            if range.end > start_region.range.end {
1482                cursor.seek_forward(&range.end);
1483            }
1484            let mut end_region = cursor.region().expect("end offset out of bounds");
1485            if !end_region.is_main_buffer {
1486                cursor.prev();
1487                if let Some(region) = cursor.region() {
1488                    end_region = region;
1489                } else {
1490                    continue;
1491                }
1492            }
1493
1494            if range.start > end_region.range.end {
1495                continue;
1496            }
1497
1498            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1499            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1500            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1501                .min(start_region.buffer_range.end);
1502            let buffer_end =
1503                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1504
1505            if start_region.excerpt.id == end_region.excerpt.id {
1506                if start_region.buffer.capability == Capability::ReadWrite
1507                    && start_region.is_main_buffer
1508                {
1509                    edited_excerpt_ids.push(start_region.excerpt.id);
1510                    buffer_edits
1511                        .entry(start_region.buffer.remote_id())
1512                        .or_default()
1513                        .push(BufferEdit {
1514                            range: buffer_start..buffer_end,
1515                            new_text,
1516                            is_insertion: true,
1517                            original_indent_column,
1518                            excerpt_id: start_region.excerpt.id,
1519                        });
1520                }
1521            } else {
1522                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1523                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1524                if start_region.buffer.capability == Capability::ReadWrite
1525                    && start_region.is_main_buffer
1526                {
1527                    edited_excerpt_ids.push(start_region.excerpt.id);
1528                    buffer_edits
1529                        .entry(start_region.buffer.remote_id())
1530                        .or_default()
1531                        .push(BufferEdit {
1532                            range: start_excerpt_range,
1533                            new_text: new_text.clone(),
1534                            is_insertion: true,
1535                            original_indent_column,
1536                            excerpt_id: start_region.excerpt.id,
1537                        });
1538                }
1539                let excerpt_id = end_region.excerpt.id;
1540                if end_region.buffer.capability == Capability::ReadWrite
1541                    && end_region.is_main_buffer
1542                {
1543                    edited_excerpt_ids.push(excerpt_id);
1544                    buffer_edits
1545                        .entry(end_region.buffer.remote_id())
1546                        .or_default()
1547                        .push(BufferEdit {
1548                            range: end_excerpt_range,
1549                            new_text: new_text.clone(),
1550                            is_insertion: false,
1551                            original_indent_column,
1552                            excerpt_id,
1553                        });
1554                }
1555
1556                cursor.seek(&range.start);
1557                cursor.next_excerpt();
1558                while let Some(region) = cursor.region() {
1559                    if region.excerpt.id == excerpt_id {
1560                        break;
1561                    }
1562                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1563                        edited_excerpt_ids.push(region.excerpt.id);
1564                        buffer_edits
1565                            .entry(region.buffer.remote_id())
1566                            .or_default()
1567                            .push(BufferEdit {
1568                                range: region.buffer_range.clone(),
1569                                new_text: new_text.clone(),
1570                                is_insertion: false,
1571                                original_indent_column,
1572                                excerpt_id: region.excerpt.id,
1573                            });
1574                    }
1575                    cursor.next_excerpt();
1576                }
1577            }
1578        }
1579        (buffer_edits, edited_excerpt_ids)
1580    }
1581
1582    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1583    where
1584        I: IntoIterator<Item = Range<S>>,
1585        S: ToOffset,
1586    {
1587        if self.read_only() || self.buffers.is_empty() {
1588            return;
1589        }
1590        self.sync_mut(cx);
1591        let empty = Arc::<str>::from("");
1592        let edits = ranges
1593            .into_iter()
1594            .map(|range| {
1595                let mut range = range.start.to_offset(self.snapshot.get_mut())
1596                    ..range.end.to_offset(&self.snapshot.get_mut());
1597                if range.start > range.end {
1598                    mem::swap(&mut range.start, &mut range.end);
1599                }
1600                (range, empty.clone())
1601            })
1602            .collect::<Vec<_>>();
1603
1604        return autoindent_ranges_internal(self, edits, cx);
1605
1606        fn autoindent_ranges_internal(
1607            this: &mut MultiBuffer,
1608            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1609            cx: &mut Context<MultiBuffer>,
1610        ) {
1611            let (buffer_edits, edited_excerpt_ids) =
1612                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1613
1614            let mut buffer_ids = Vec::new();
1615            for (buffer_id, mut edits) in buffer_edits {
1616                buffer_ids.push(buffer_id);
1617                edits.sort_unstable_by_key(|edit| edit.range.start);
1618
1619                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1620                for edit in edits {
1621                    if let Some(last_range) = ranges.last_mut()
1622                        && edit.range.start <= last_range.end
1623                    {
1624                        last_range.end = last_range.end.max(edit.range.end);
1625                        continue;
1626                    }
1627                    ranges.push(edit.range);
1628                }
1629
1630                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1631                    buffer.autoindent_ranges(ranges, cx);
1632                })
1633            }
1634
1635            cx.emit(Event::ExcerptsEdited {
1636                excerpt_ids: edited_excerpt_ids,
1637                buffer_ids,
1638            });
1639        }
1640    }
1641
1642    pub fn set_active_selections(
1643        &self,
1644        selections: &[Selection<Anchor>],
1645        line_mode: bool,
1646        cursor_shape: CursorShape,
1647        cx: &mut Context<Self>,
1648    ) {
1649        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1650            Default::default();
1651        let snapshot = self.read(cx);
1652        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1653        for selection in selections {
1654            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1655            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1656
1657            cursor.seek(&Some(start_locator), Bias::Left);
1658            while let Some(excerpt) = cursor.item()
1659                && excerpt.locator <= *end_locator
1660            {
1661                let mut start = excerpt.range.context.start;
1662                let mut end = excerpt.range.context.end;
1663                if excerpt.id == selection.start.excerpt_id {
1664                    start = selection.start.text_anchor;
1665                }
1666                if excerpt.id == selection.end.excerpt_id {
1667                    end = selection.end.text_anchor;
1668                }
1669                selections_by_buffer
1670                    .entry(excerpt.buffer_id)
1671                    .or_default()
1672                    .push(Selection {
1673                        id: selection.id,
1674                        start,
1675                        end,
1676                        reversed: selection.reversed,
1677                        goal: selection.goal,
1678                    });
1679
1680                cursor.next();
1681            }
1682        }
1683
1684        for (buffer_id, buffer_state) in self.buffers.iter() {
1685            if !selections_by_buffer.contains_key(buffer_id) {
1686                buffer_state
1687                    .buffer
1688                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1689            }
1690        }
1691
1692        for (buffer_id, mut selections) in selections_by_buffer {
1693            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1694                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1695                let mut selections = selections.into_iter().peekable();
1696                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1697                    let mut selection = selections.next()?;
1698                    while let Some(next_selection) = selections.peek() {
1699                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1700                            let next_selection = selections.next().unwrap();
1701                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1702                                selection.end = next_selection.end;
1703                            }
1704                        } else {
1705                            break;
1706                        }
1707                    }
1708                    Some(selection)
1709                }));
1710                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1711            });
1712        }
1713    }
1714
1715    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1716        for buffer in self.buffers.values() {
1717            buffer
1718                .buffer
1719                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1720        }
1721    }
1722
1723    pub fn push_excerpts<O>(
1724        &mut self,
1725        buffer: Entity<Buffer>,
1726        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1727        cx: &mut Context<Self>,
1728    ) -> Vec<ExcerptId>
1729    where
1730        O: text::ToOffset,
1731    {
1732        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1733    }
1734
1735    #[instrument(skip_all)]
1736    fn merge_excerpt_ranges<'a>(
1737        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1738    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1739        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1740        let mut counts: Vec<usize> = Vec::new();
1741        for range in expanded_ranges {
1742            if let Some(last_range) = merged_ranges.last_mut() {
1743                assert!(
1744                    last_range.context.start <= range.context.start,
1745                    "ranges must be sorted: {last_range:?} <= {range:?}"
1746                );
1747                if last_range.context.end >= range.context.start
1748                    || last_range.context.end.row + 1 == range.context.start.row
1749                {
1750                    last_range.context.end = range.context.end.max(last_range.context.end);
1751                    *counts.last_mut().unwrap() += 1;
1752                    continue;
1753                }
1754            }
1755            merged_ranges.push(range.clone());
1756            counts.push(1);
1757        }
1758        (merged_ranges, counts)
1759    }
1760
1761    pub fn insert_excerpts_after<O>(
1762        &mut self,
1763        prev_excerpt_id: ExcerptId,
1764        buffer: Entity<Buffer>,
1765        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1766        cx: &mut Context<Self>,
1767    ) -> Vec<ExcerptId>
1768    where
1769        O: text::ToOffset,
1770    {
1771        let mut ids = Vec::new();
1772        let mut next_excerpt_id =
1773            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1774                last_entry.id.0 + 1
1775            } else {
1776                1
1777            };
1778        self.insert_excerpts_with_ids_after(
1779            prev_excerpt_id,
1780            buffer,
1781            ranges.into_iter().map(|range| {
1782                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1783                ids.push(id);
1784                (id, range)
1785            }),
1786            cx,
1787        );
1788        ids
1789    }
1790
1791    pub fn insert_excerpts_with_ids_after<O>(
1792        &mut self,
1793        prev_excerpt_id: ExcerptId,
1794        buffer: Entity<Buffer>,
1795        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1796        cx: &mut Context<Self>,
1797    ) where
1798        O: text::ToOffset,
1799    {
1800        assert_eq!(self.history.transaction_depth(), 0);
1801        let mut ranges = ranges.into_iter().peekable();
1802        if ranges.peek().is_none() {
1803            return Default::default();
1804        }
1805
1806        self.sync_mut(cx);
1807
1808        let buffer_snapshot = buffer.read(cx).snapshot();
1809        let buffer_id = buffer_snapshot.remote_id();
1810
1811        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1812            self.buffer_changed_since_sync.replace(true);
1813            buffer.update(cx, |buffer, _| {
1814                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1815            });
1816            BufferState {
1817                last_version: RefCell::new(buffer_snapshot.version().clone()),
1818                last_non_text_state_update_count: Cell::new(
1819                    buffer_snapshot.non_text_state_update_count(),
1820                ),
1821                excerpts: Default::default(),
1822                _subscriptions: [
1823                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1824                    cx.subscribe(&buffer, Self::on_buffer_event),
1825                ],
1826                buffer: buffer.clone(),
1827            }
1828        });
1829
1830        let mut snapshot = self.snapshot.get_mut();
1831
1832        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1833        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1834        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1835        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1836        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1837
1838        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1839        new_excerpts.update_last(
1840            |excerpt| {
1841                excerpt.has_trailing_newline = true;
1842            },
1843            (),
1844        );
1845
1846        let next_locator = if let Some(excerpt) = cursor.item() {
1847            excerpt.locator.clone()
1848        } else {
1849            Locator::max()
1850        };
1851
1852        let mut excerpts = Vec::new();
1853        let buffer_snapshot = Arc::new(buffer_snapshot);
1854        while let Some((id, range)) = ranges.next() {
1855            let locator = Locator::between(&prev_locator, &next_locator);
1856            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1857                buffer_state.excerpts.insert(ix, locator.clone());
1858            }
1859            let range = ExcerptRange {
1860                context: buffer_snapshot.anchor_before(&range.context.start)
1861                    ..buffer_snapshot.anchor_after(&range.context.end),
1862                primary: buffer_snapshot.anchor_before(&range.primary.start)
1863                    ..buffer_snapshot.anchor_after(&range.primary.end),
1864            };
1865            excerpts.push((id, range.clone()));
1866            let excerpt = Excerpt::new(
1867                id,
1868                locator.clone(),
1869                buffer_id,
1870                buffer_snapshot.clone(),
1871                range,
1872                ranges.peek().is_some() || cursor.item().is_some(),
1873            );
1874            new_excerpts.push(excerpt, ());
1875            prev_locator = locator.clone();
1876
1877            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1878                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1879            }
1880            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1881        }
1882        snapshot
1883            .buffer_locators
1884            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1885
1886        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1887
1888        let suffix = cursor.suffix();
1889        let changed_trailing_excerpt = suffix.is_empty();
1890        new_excerpts.append(suffix, ());
1891        drop(cursor);
1892        snapshot.excerpts = new_excerpts;
1893        snapshot.excerpt_ids = new_excerpt_ids;
1894        if changed_trailing_excerpt {
1895            snapshot.trailing_excerpt_update_count += 1;
1896        }
1897
1898        let edits = Self::sync_diff_transforms(
1899            &mut snapshot,
1900            vec![Edit {
1901                old: edit_start..edit_start,
1902                new: edit_start..edit_end,
1903            }],
1904            DiffChangeKind::BufferEdited,
1905        );
1906        if !edits.is_empty() {
1907            self.subscriptions.publish(edits);
1908        }
1909
1910        cx.emit(Event::Edited {
1911            edited_buffer: None,
1912        });
1913        cx.emit(Event::ExcerptsAdded {
1914            buffer,
1915            predecessor: prev_excerpt_id,
1916            excerpts,
1917        });
1918        cx.notify();
1919    }
1920
1921    pub fn clear(&mut self, cx: &mut Context<Self>) {
1922        self.sync_mut(cx);
1923        let ids = self.excerpt_ids();
1924        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1925        self.excerpts_by_path.clear();
1926        self.paths_by_excerpt.clear();
1927        let MultiBufferSnapshot {
1928            excerpts,
1929            buffer_locators,
1930            diffs: _,
1931            diff_transforms: _,
1932            non_text_state_update_count: _,
1933            edit_count: _,
1934            is_dirty,
1935            has_deleted_file,
1936            has_conflict,
1937            has_inverted_diff,
1938            singleton: _,
1939            excerpt_ids: _,
1940            replaced_excerpts,
1941            trailing_excerpt_update_count,
1942            all_diff_hunks_expanded: _,
1943            show_deleted_hunks: _,
1944            use_extended_diff_range: _,
1945            show_headers: _,
1946        } = self.snapshot.get_mut();
1947        buffer_locators.clear();
1948        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1949        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1950        *excerpts = Default::default();
1951        *trailing_excerpt_update_count += 1;
1952        *is_dirty = false;
1953        *has_deleted_file = false;
1954        *has_conflict = false;
1955        *has_inverted_diff = false;
1956        replaced_excerpts.clear();
1957
1958        let edits = Self::sync_diff_transforms(
1959            self.snapshot.get_mut(),
1960            vec![Edit {
1961                old: start..prev_len,
1962                new: start..start,
1963            }],
1964            DiffChangeKind::BufferEdited,
1965        );
1966        if !edits.is_empty() {
1967            self.subscriptions.publish(edits);
1968        }
1969        cx.emit(Event::Edited {
1970            edited_buffer: None,
1971        });
1972        cx.emit(Event::ExcerptsRemoved {
1973            ids,
1974            removed_buffer_ids,
1975        });
1976        cx.notify();
1977    }
1978
1979    #[ztracing::instrument(skip_all)]
1980    pub fn excerpts_for_buffer(
1981        &self,
1982        buffer_id: BufferId,
1983        cx: &App,
1984    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1985        let mut excerpts = Vec::new();
1986        let snapshot = self.read(cx);
1987        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1988        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1989            for locator in &**locators {
1990                cursor.seek_forward(&Some(locator), Bias::Left);
1991                if let Some(excerpt) = cursor.item()
1992                    && excerpt.locator == *locator
1993                {
1994                    excerpts.push((excerpt.id, excerpt.range.clone()));
1995                }
1996            }
1997        }
1998
1999        excerpts
2000    }
2001
2002    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2003        let snapshot = self.read(cx);
2004        let mut excerpts = snapshot
2005            .excerpts
2006            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2007        let mut diff_transforms = snapshot
2008            .diff_transforms
2009            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2010        diff_transforms.next();
2011        let locators = snapshot
2012            .buffer_locators
2013            .get(&buffer_id)
2014            .into_iter()
2015            .flat_map(|v| &**v);
2016        let mut result = Vec::new();
2017        for locator in locators {
2018            excerpts.seek_forward(&Some(locator), Bias::Left);
2019            if let Some(excerpt) = excerpts.item()
2020                && excerpt.locator == *locator
2021            {
2022                let excerpt_start = excerpts.start().1;
2023                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2024
2025                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2026                let overshoot = excerpt_start - diff_transforms.start().0;
2027                let start = diff_transforms.start().1 + overshoot;
2028
2029                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2030                let overshoot = excerpt_end - diff_transforms.start().0;
2031                let end = diff_transforms.start().1 + overshoot;
2032
2033                result.push(start.0..end.0)
2034            }
2035        }
2036        result
2037    }
2038
2039    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2040        self.snapshot
2041            .borrow()
2042            .excerpts
2043            .iter()
2044            .map(|entry| entry.buffer_id)
2045            .collect()
2046    }
2047
2048    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2049        self.snapshot
2050            .borrow()
2051            .excerpts
2052            .iter()
2053            .map(|entry| entry.id)
2054            .collect()
2055    }
2056
2057    pub fn excerpt_containing(
2058        &self,
2059        position: impl ToOffset,
2060        cx: &App,
2061    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2062        let snapshot = self.read(cx);
2063        let offset = position.to_offset(&snapshot);
2064
2065        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2066        cursor.seek(&offset);
2067        cursor
2068            .excerpt()
2069            .or_else(|| snapshot.excerpts.last())
2070            .map(|excerpt| {
2071                (
2072                    excerpt.id,
2073                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2074                    excerpt.range.context.clone(),
2075                )
2076            })
2077    }
2078
2079    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2080        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2081            self.buffer(buffer_id)
2082        } else {
2083            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2084            Some(buffer)
2085        }
2086    }
2087
2088    // If point is at the end of the buffer, the last excerpt is returned
2089    pub fn point_to_buffer_offset<T: ToOffset>(
2090        &self,
2091        point: T,
2092        cx: &App,
2093    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2094        let snapshot = self.read(cx);
2095        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2096        Some((
2097            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2098            offset,
2099        ))
2100    }
2101
2102    // If point is at the end of the buffer, the last excerpt is returned
2103    pub fn point_to_buffer_point<T: ToPoint>(
2104        &self,
2105        point: T,
2106        cx: &App,
2107    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2108        let snapshot = self.read(cx);
2109        let (buffer, point, is_main_buffer) =
2110            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2111        Some((
2112            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2113            point,
2114            is_main_buffer,
2115        ))
2116    }
2117
2118    pub fn buffer_point_to_anchor(
2119        &self,
2120        // todo(lw): We shouldn't need this?
2121        buffer: &Entity<Buffer>,
2122        point: Point,
2123        cx: &App,
2124    ) -> Option<Anchor> {
2125        let mut found = None;
2126        let snapshot = buffer.read(cx).snapshot();
2127        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2128            let start = range.context.start.to_point(&snapshot);
2129            let end = range.context.end.to_point(&snapshot);
2130            if start <= point && point < end {
2131                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2132                break;
2133            }
2134            if point < start {
2135                found = Some((start, excerpt_id));
2136            }
2137            if point > end {
2138                found = Some((end, excerpt_id));
2139            }
2140        }
2141
2142        found.map(|(point, excerpt_id)| {
2143            let text_anchor = snapshot.anchor_after(point);
2144            Anchor::in_buffer(excerpt_id, text_anchor)
2145        })
2146    }
2147
2148    pub fn buffer_anchor_to_anchor(
2149        &self,
2150        // todo(lw): We shouldn't need this?
2151        buffer: &Entity<Buffer>,
2152        anchor: text::Anchor,
2153        cx: &App,
2154    ) -> Option<Anchor> {
2155        let snapshot = buffer.read(cx).snapshot();
2156        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2157            if range.context.start.cmp(&anchor, &snapshot).is_le()
2158                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2159            {
2160                return Some(Anchor::in_buffer(excerpt_id, anchor));
2161            }
2162        }
2163
2164        None
2165    }
2166
2167    pub fn merge_excerpts(
2168        &mut self,
2169        excerpt_ids: &[ExcerptId],
2170        cx: &mut Context<Self>,
2171    ) -> ExcerptId {
2172        debug_assert!(!excerpt_ids.is_empty());
2173        if excerpt_ids.len() == 1 {
2174            return excerpt_ids[0];
2175        }
2176
2177        let snapshot = self.snapshot(cx);
2178
2179        let first_range = snapshot
2180            .context_range_for_excerpt(excerpt_ids[0])
2181            .expect("first excerpt must exist");
2182        let last_range = snapshot
2183            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2184            .expect("last excerpt must exist");
2185
2186        let union_range = first_range.start..last_range.end;
2187
2188        drop(snapshot);
2189
2190        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2191        self.remove_excerpts(excerpt_ids[1..].iter().copied(), cx);
2192
2193        excerpt_ids[0]
2194    }
2195
2196    pub fn remove_excerpts(
2197        &mut self,
2198        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2199        cx: &mut Context<Self>,
2200    ) {
2201        self.sync_mut(cx);
2202        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2203        if ids.is_empty() {
2204            return;
2205        }
2206        self.buffer_changed_since_sync.replace(true);
2207
2208        let mut snapshot = self.snapshot.get_mut();
2209        let mut new_excerpts = SumTree::default();
2210        let mut cursor = snapshot
2211            .excerpts
2212            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2213        let mut edits = Vec::new();
2214        let mut excerpt_ids = ids.iter().copied().peekable();
2215        let mut removed_buffer_ids = Vec::new();
2216        let mut removed_excerpts_for_buffers = HashSet::default();
2217
2218        while let Some(excerpt_id) = excerpt_ids.next() {
2219            self.paths_by_excerpt.remove(&excerpt_id);
2220            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2221            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2222            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2223
2224            if let Some(mut excerpt) = cursor.item() {
2225                if excerpt.id != excerpt_id {
2226                    continue;
2227                }
2228                let mut old_start = cursor.start().1;
2229
2230                // Skip over the removed excerpt.
2231                'remove_excerpts: loop {
2232                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2233                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2234                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2235                        if buffer_state.excerpts.is_empty() {
2236                            log::debug!(
2237                                "removing buffer and diff for buffer {}",
2238                                excerpt.buffer_id
2239                            );
2240                            self.buffers.remove(&excerpt.buffer_id);
2241                            removed_buffer_ids.push(excerpt.buffer_id);
2242                        }
2243                    }
2244                    cursor.next();
2245
2246                    // Skip over any subsequent excerpts that are also removed.
2247                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2248                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2249                        if let Some(next_excerpt) = cursor.item()
2250                            && next_excerpt.locator == *next_locator
2251                        {
2252                            excerpt_ids.next();
2253                            excerpt = next_excerpt;
2254                            continue 'remove_excerpts;
2255                        }
2256                    }
2257
2258                    break;
2259                }
2260
2261                // When removing the last excerpt, remove the trailing newline from
2262                // the previous excerpt.
2263                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2264                    old_start -= 1;
2265                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2266                }
2267
2268                // Push an edit for the removal of this run of excerpts.
2269                let old_end = cursor.start().1;
2270                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2271                edits.push(Edit {
2272                    old: old_start..old_end,
2273                    new: new_start..new_start,
2274                });
2275            }
2276        }
2277        let suffix = cursor.suffix();
2278        let changed_trailing_excerpt = suffix.is_empty();
2279        new_excerpts.append(suffix, ());
2280        drop(cursor);
2281        for buffer_id in removed_excerpts_for_buffers {
2282            match self.buffers.get(&buffer_id) {
2283                Some(buffer_state) => {
2284                    snapshot
2285                        .buffer_locators
2286                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2287                }
2288                None => {
2289                    snapshot.buffer_locators.remove(&buffer_id);
2290                }
2291            }
2292        }
2293        snapshot.excerpts = new_excerpts;
2294        for buffer_id in &removed_buffer_ids {
2295            self.diffs.remove(buffer_id);
2296            snapshot.diffs.remove(buffer_id);
2297        }
2298
2299        // Recalculate has_inverted_diff after removing diffs
2300        if !removed_buffer_ids.is_empty() {
2301            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2302        }
2303
2304        if changed_trailing_excerpt {
2305            snapshot.trailing_excerpt_update_count += 1;
2306        }
2307
2308        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2309        if !edits.is_empty() {
2310            self.subscriptions.publish(edits);
2311        }
2312        cx.emit(Event::Edited {
2313            edited_buffer: None,
2314        });
2315        cx.emit(Event::ExcerptsRemoved {
2316            ids,
2317            removed_buffer_ids,
2318        });
2319        cx.notify();
2320    }
2321
2322    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2323        &self,
2324        anchors: Anchors,
2325        cx: &mut Context<Self>,
2326    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2327        let mut error = None;
2328        let mut futures = Vec::new();
2329        for anchor in anchors {
2330            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2331                if let Some(buffer) = self.buffers.get(&buffer_id) {
2332                    buffer.buffer.update(cx, |buffer, _| {
2333                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2334                    });
2335                } else {
2336                    error = Some(anyhow!(
2337                        "buffer {buffer_id} is not part of this multi-buffer"
2338                    ));
2339                    break;
2340                }
2341            }
2342        }
2343        async move {
2344            if let Some(error) = error {
2345                Err(error)?;
2346            }
2347            for future in futures {
2348                future.await?;
2349            }
2350            Ok(())
2351        }
2352    }
2353
2354    pub fn text_anchor_for_position<T: ToOffset>(
2355        &self,
2356        position: T,
2357        cx: &App,
2358    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2359        let snapshot = self.read(cx);
2360        let anchor = snapshot.anchor_before(position);
2361        let buffer = self
2362            .buffers
2363            .get(&anchor.text_anchor.buffer_id?)?
2364            .buffer
2365            .clone();
2366        Some((buffer, anchor.text_anchor))
2367    }
2368
2369    fn on_buffer_event(
2370        &mut self,
2371        buffer: Entity<Buffer>,
2372        event: &language::BufferEvent,
2373        cx: &mut Context<Self>,
2374    ) {
2375        use language::BufferEvent;
2376        let buffer_id = buffer.read(cx).remote_id();
2377        cx.emit(match event {
2378            BufferEvent::Edited => Event::Edited {
2379                edited_buffer: Some(buffer),
2380            },
2381            BufferEvent::DirtyChanged => Event::DirtyChanged,
2382            BufferEvent::Saved => Event::Saved,
2383            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2384            BufferEvent::Reloaded => Event::Reloaded,
2385            BufferEvent::LanguageChanged(has_language) => {
2386                Event::LanguageChanged(buffer_id, *has_language)
2387            }
2388            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2389            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2390            BufferEvent::CapabilityChanged => {
2391                self.capability = buffer.read(cx).capability();
2392                return;
2393            }
2394            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2395        });
2396    }
2397
2398    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2399        let diff = diff.read(cx);
2400        let buffer_id = diff.buffer_id;
2401        let diff = DiffStateSnapshot {
2402            diff: diff.snapshot(cx),
2403            is_inverted: false,
2404        };
2405        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2406    }
2407
2408    fn inverted_buffer_diff_language_changed(
2409        &mut self,
2410        diff: Entity<BufferDiff>,
2411        cx: &mut Context<Self>,
2412    ) {
2413        let base_text_buffer_id = diff.read(cx).base_text_buffer().read(cx).remote_id();
2414        let diff = diff.read(cx);
2415        let diff = DiffStateSnapshot {
2416            diff: diff.snapshot(cx),
2417            is_inverted: true,
2418        };
2419        self.snapshot
2420            .get_mut()
2421            .diffs
2422            .insert(base_text_buffer_id, diff);
2423    }
2424
2425    fn buffer_diff_changed(
2426        &mut self,
2427        diff: Entity<BufferDiff>,
2428        range: Range<text::Anchor>,
2429        cx: &mut Context<Self>,
2430    ) {
2431        self.sync_mut(cx);
2432
2433        let diff = diff.read(cx);
2434        let buffer_id = diff.buffer_id;
2435
2436        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2437            return;
2438        };
2439        let new_diff = DiffStateSnapshot {
2440            diff: diff.snapshot(cx),
2441            is_inverted: false,
2442        };
2443        let mut snapshot = self.snapshot.get_mut();
2444        let base_text_changed = snapshot
2445            .diffs
2446            .get(&buffer_id)
2447            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2448        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2449
2450        let buffer = buffer_state.buffer.read(cx);
2451        let diff_change_range = range.to_offset(buffer);
2452
2453        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2454        let edits = Self::sync_diff_transforms(
2455            &mut snapshot,
2456            excerpt_edits,
2457            DiffChangeKind::DiffUpdated {
2458                base_changed: base_text_changed,
2459            },
2460        );
2461        if !edits.is_empty() {
2462            self.subscriptions.publish(edits);
2463        }
2464        cx.emit(Event::Edited {
2465            edited_buffer: None,
2466        });
2467    }
2468
2469    fn inverted_buffer_diff_changed(
2470        &mut self,
2471        diff: Entity<BufferDiff>,
2472        diff_change_range: Range<usize>,
2473        cx: &mut Context<Self>,
2474    ) {
2475        self.sync_mut(cx);
2476
2477        let diff = diff.read(cx);
2478        let base_text_buffer_id = diff.base_text_buffer().read(cx).remote_id();
2479        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2480            return;
2481        };
2482
2483        let new_diff = DiffStateSnapshot {
2484            diff: diff.snapshot(cx),
2485            is_inverted: true,
2486        };
2487        let mut snapshot = self.snapshot.get_mut();
2488        snapshot
2489            .diffs
2490            .insert_or_replace(base_text_buffer_id, new_diff);
2491
2492        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2493        let edits = Self::sync_diff_transforms(
2494            &mut snapshot,
2495            excerpt_edits,
2496            DiffChangeKind::DiffUpdated {
2497                // We don't read this field for inverted diffs.
2498                base_changed: false,
2499            },
2500        );
2501        if !edits.is_empty() {
2502            self.subscriptions.publish(edits);
2503        }
2504        cx.emit(Event::Edited {
2505            edited_buffer: None,
2506        });
2507    }
2508
2509    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2510        self.buffers.values().map(|state| state.buffer.clone())
2511    }
2512
2513    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2514        self.all_buffers_iter().collect()
2515    }
2516
2517    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2518        self.buffers.keys().copied()
2519    }
2520
2521    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2522        self.all_buffer_ids_iter().collect()
2523    }
2524
2525    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2526        self.buffers
2527            .get(&buffer_id)
2528            .map(|state| state.buffer.clone())
2529    }
2530
2531    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2532        self.point_to_buffer_offset(point, cx)
2533            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2534    }
2535
2536    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2537        let buffer_id = self
2538            .snapshot
2539            .borrow()
2540            .excerpts
2541            .first()
2542            .map(|excerpt| excerpt.buffer.remote_id());
2543        buffer_id
2544            .and_then(|buffer_id| self.buffer(buffer_id))
2545            .map(|buffer| {
2546                let buffer = buffer.read(cx);
2547                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2548            })
2549            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2550    }
2551
2552    pub fn language_settings_at<'a, T: ToOffset>(
2553        &'a self,
2554        point: T,
2555        cx: &'a App,
2556    ) -> Cow<'a, LanguageSettings> {
2557        let mut language = None;
2558        let mut file = None;
2559        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2560            let buffer = buffer.read(cx);
2561            language = buffer.language_at(offset);
2562            file = buffer.file();
2563        }
2564        language_settings(language.map(|l| l.name()), file, cx)
2565    }
2566
2567    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2568        self.buffers.values().for_each(|state| f(&state.buffer))
2569    }
2570
2571    pub fn explicit_title(&self) -> Option<&str> {
2572        self.title.as_deref()
2573    }
2574
2575    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2576        if let Some(title) = self.title.as_ref() {
2577            return title.into();
2578        }
2579
2580        if let Some(buffer) = self.as_singleton() {
2581            let buffer = buffer.read(cx);
2582
2583            if let Some(file) = buffer.file() {
2584                return file.file_name(cx).into();
2585            }
2586
2587            if let Some(title) = self.buffer_content_title(buffer) {
2588                return title;
2589            }
2590        };
2591
2592        "untitled".into()
2593    }
2594
2595    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2596        let mut is_leading_whitespace = true;
2597        let mut count = 0;
2598        let mut prev_was_space = false;
2599        let mut title = String::new();
2600
2601        for ch in buffer.snapshot().chars() {
2602            if is_leading_whitespace && ch.is_whitespace() {
2603                continue;
2604            }
2605
2606            is_leading_whitespace = false;
2607
2608            if ch == '\n' || count >= 40 {
2609                break;
2610            }
2611
2612            if ch.is_whitespace() {
2613                if !prev_was_space {
2614                    title.push(' ');
2615                    count += 1;
2616                    prev_was_space = true;
2617                }
2618            } else {
2619                title.push(ch);
2620                count += 1;
2621                prev_was_space = false;
2622            }
2623        }
2624
2625        let title = title.trim_end().to_string();
2626
2627        if title.is_empty() {
2628            return None;
2629        }
2630
2631        Some(title.into())
2632    }
2633
2634    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2635        self.title = Some(title);
2636        cx.notify();
2637    }
2638
2639    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2640    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2641        for buffer_state in self.buffers.values() {
2642            buffer_state
2643                .buffer
2644                .update(cx, |buffer, _cx| buffer.refresh_preview());
2645        }
2646    }
2647
2648    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2649    pub fn preserve_preview(&self, cx: &App) -> bool {
2650        self.buffers
2651            .values()
2652            .all(|state| state.buffer.read(cx).preserve_preview())
2653    }
2654
2655    #[cfg(any(test, feature = "test-support"))]
2656    pub fn is_parsing(&self, cx: &App) -> bool {
2657        self.as_singleton().unwrap().read(cx).is_parsing()
2658    }
2659
2660    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2661        let buffer_id = diff.read(cx).buffer_id;
2662
2663        if let Some(existing_diff) = self.diff_for(buffer_id)
2664            && diff.entity_id() == existing_diff.entity_id()
2665        {
2666            return;
2667        }
2668
2669        self.buffer_diff_changed(
2670            diff.clone(),
2671            text::Anchor::min_max_range_for_buffer(buffer_id),
2672            cx,
2673        );
2674        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2675    }
2676
2677    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2678        let snapshot = diff.read(cx).base_text(cx);
2679        let base_text_buffer_id = snapshot.remote_id();
2680        let diff_change_range = 0..snapshot.len();
2681        self.snapshot.get_mut().has_inverted_diff = true;
2682        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2683        self.diffs
2684            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2685    }
2686
2687    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2688        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2689    }
2690
2691    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2692        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2693    }
2694
2695    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2696        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2697    }
2698
2699    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2700        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2701        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2702    }
2703
2704    pub fn all_diff_hunks_expanded(&self) -> bool {
2705        self.snapshot.borrow().all_diff_hunks_expanded
2706    }
2707
2708    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2709        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2710        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2711    }
2712
2713    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2714        self.snapshot.get_mut().show_deleted_hunks = show;
2715
2716        self.sync_mut(cx);
2717
2718        let old_len = self.snapshot.borrow().len();
2719
2720        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2721        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2722
2723        let new_len = self.snapshot.borrow().len();
2724
2725        self.subscriptions.publish(vec![Edit {
2726            old: MultiBufferOffset(0)..old_len,
2727            new: MultiBufferOffset(0)..new_len,
2728        }]);
2729
2730        cx.emit(Event::DiffHunksToggled);
2731        cx.emit(Event::Edited {
2732            edited_buffer: None,
2733        });
2734    }
2735
2736    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2737        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2738    }
2739
2740    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2741        self.read(cx)
2742            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2743            .nth(1)
2744            .is_some()
2745    }
2746
2747    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2748        let snapshot = self.read(cx);
2749        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2750        let offset_range = range.to_offset(&snapshot);
2751        cursor.seek(&offset_range.start, Bias::Left);
2752        while let Some(item) = cursor.item() {
2753            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2754                break;
2755            }
2756            if item.hunk_info().is_some() {
2757                return true;
2758            }
2759            cursor.next();
2760        }
2761        false
2762    }
2763
2764    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2765        let snapshot = self.read(cx);
2766        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2767        for range in ranges {
2768            let range = range.to_point(&snapshot);
2769            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2770            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2771                .min(snapshot.len());
2772            cursor.seek(&start, Bias::Right);
2773            while let Some(item) = cursor.item() {
2774                if *cursor.start() >= end {
2775                    break;
2776                }
2777                if item.hunk_info().is_some() {
2778                    return true;
2779                }
2780                cursor.next();
2781            }
2782        }
2783        false
2784    }
2785
2786    pub fn expand_or_collapse_diff_hunks_inner(
2787        &mut self,
2788        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2789        expand: bool,
2790        cx: &mut Context<Self>,
2791    ) -> Vec<Edit<MultiBufferOffset>> {
2792        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2793            return Vec::new();
2794        }
2795        self.sync_mut(cx);
2796        let mut snapshot = self.snapshot.get_mut();
2797        let mut excerpt_edits = Vec::new();
2798        let mut last_hunk_row = None;
2799        for (range, end_excerpt_id) in ranges {
2800            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2801                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2802                    continue;
2803                }
2804                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2805                    continue;
2806                }
2807                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2808                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2809                let start = snapshot.excerpt_offset_for_anchor(&start);
2810                let end = snapshot.excerpt_offset_for_anchor(&end);
2811                last_hunk_row = Some(diff_hunk.row_range.start);
2812                excerpt_edits.push(text::Edit {
2813                    old: start..end,
2814                    new: start..end,
2815                });
2816            }
2817        }
2818
2819        Self::sync_diff_transforms(
2820            &mut snapshot,
2821            excerpt_edits,
2822            DiffChangeKind::ExpandOrCollapseHunks { expand },
2823        )
2824    }
2825
2826    pub fn expand_or_collapse_diff_hunks(
2827        &mut self,
2828        ranges: Vec<Range<Anchor>>,
2829        expand: bool,
2830        cx: &mut Context<Self>,
2831    ) {
2832        let snapshot = self.snapshot.borrow().clone();
2833        let ranges = ranges.iter().map(move |range| {
2834            let end_excerpt_id = range.end.excerpt_id;
2835            let range = range.to_point(&snapshot);
2836            let mut peek_end = range.end;
2837            if range.end.row < snapshot.max_row().0 {
2838                peek_end = Point::new(range.end.row + 1, 0);
2839            };
2840            (range.start..peek_end, end_excerpt_id)
2841        });
2842        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2843        if !edits.is_empty() {
2844            self.subscriptions.publish(edits);
2845        }
2846        cx.emit(Event::DiffHunksToggled);
2847        cx.emit(Event::Edited {
2848            edited_buffer: None,
2849        });
2850    }
2851
2852    pub fn resize_excerpt(
2853        &mut self,
2854        id: ExcerptId,
2855        range: Range<text::Anchor>,
2856        cx: &mut Context<Self>,
2857    ) {
2858        self.sync_mut(cx);
2859
2860        let mut snapshot = self.snapshot.get_mut();
2861        let locator = snapshot.excerpt_locator_for_id(id);
2862        let mut new_excerpts = SumTree::default();
2863        let mut cursor = snapshot
2864            .excerpts
2865            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2866        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2867
2868        let prefix = cursor.slice(&Some(locator), Bias::Left);
2869        new_excerpts.append(prefix, ());
2870
2871        let mut excerpt = cursor.item().unwrap().clone();
2872        let old_text_len = excerpt.text_summary.len;
2873
2874        excerpt.range.context.start = range.start;
2875        excerpt.range.context.end = range.end;
2876        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2877
2878        excerpt.text_summary = excerpt
2879            .buffer
2880            .text_summary_for_range(excerpt.range.context.clone());
2881
2882        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2883        let old_start_offset = cursor.start().1;
2884        let new_text_len = excerpt.text_summary.len;
2885        let edit = Edit {
2886            old: old_start_offset..old_start_offset + old_text_len,
2887            new: new_start_offset..new_start_offset + new_text_len,
2888        };
2889
2890        if let Some(last_edit) = edits.last_mut() {
2891            if last_edit.old.end == edit.old.start {
2892                last_edit.old.end = edit.old.end;
2893                last_edit.new.end = edit.new.end;
2894            } else {
2895                edits.push(edit);
2896            }
2897        } else {
2898            edits.push(edit);
2899        }
2900
2901        new_excerpts.push(excerpt, ());
2902
2903        cursor.next();
2904
2905        new_excerpts.append(cursor.suffix(), ());
2906
2907        drop(cursor);
2908        snapshot.excerpts = new_excerpts;
2909
2910        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2911        if !edits.is_empty() {
2912            self.subscriptions.publish(edits);
2913        }
2914        cx.emit(Event::Edited {
2915            edited_buffer: None,
2916        });
2917        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2918        cx.notify();
2919    }
2920
2921    pub fn expand_excerpts(
2922        &mut self,
2923        ids: impl IntoIterator<Item = ExcerptId>,
2924        line_count: u32,
2925        direction: ExpandExcerptDirection,
2926        cx: &mut Context<Self>,
2927    ) {
2928        if line_count == 0 {
2929            return;
2930        }
2931        self.sync_mut(cx);
2932        if !self.excerpts_by_path.is_empty() {
2933            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2934            return;
2935        }
2936        let mut snapshot = self.snapshot.get_mut();
2937
2938        let ids = ids.into_iter().collect::<Vec<_>>();
2939        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2940        let mut new_excerpts = SumTree::default();
2941        let mut cursor = snapshot
2942            .excerpts
2943            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2944        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2945
2946        for locator in &locators {
2947            let prefix = cursor.slice(&Some(locator), Bias::Left);
2948            new_excerpts.append(prefix, ());
2949
2950            let mut excerpt = cursor.item().unwrap().clone();
2951            let old_text_len = excerpt.text_summary.len;
2952
2953            let up_line_count = if direction.should_expand_up() {
2954                line_count
2955            } else {
2956                0
2957            };
2958
2959            let start_row = excerpt
2960                .range
2961                .context
2962                .start
2963                .to_point(&excerpt.buffer)
2964                .row
2965                .saturating_sub(up_line_count);
2966            let start_point = Point::new(start_row, 0);
2967            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2968
2969            let down_line_count = if direction.should_expand_down() {
2970                line_count
2971            } else {
2972                0
2973            };
2974
2975            let mut end_point = excerpt.buffer.clip_point(
2976                excerpt.range.context.end.to_point(&excerpt.buffer)
2977                    + Point::new(down_line_count, 0),
2978                Bias::Left,
2979            );
2980            end_point.column = excerpt.buffer.line_len(end_point.row);
2981            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2982            excerpt.max_buffer_row = end_point.row;
2983
2984            excerpt.text_summary = excerpt
2985                .buffer
2986                .text_summary_for_range(excerpt.range.context.clone());
2987
2988            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2989            let old_start_offset = cursor.start().1;
2990            let new_text_len = excerpt.text_summary.len;
2991            let edit = Edit {
2992                old: old_start_offset..old_start_offset + old_text_len,
2993                new: new_start_offset..new_start_offset + new_text_len,
2994            };
2995
2996            if let Some(last_edit) = edits.last_mut() {
2997                if last_edit.old.end == edit.old.start {
2998                    last_edit.old.end = edit.old.end;
2999                    last_edit.new.end = edit.new.end;
3000                } else {
3001                    edits.push(edit);
3002                }
3003            } else {
3004                edits.push(edit);
3005            }
3006
3007            new_excerpts.push(excerpt, ());
3008
3009            cursor.next();
3010        }
3011
3012        new_excerpts.append(cursor.suffix(), ());
3013
3014        drop(cursor);
3015        snapshot.excerpts = new_excerpts;
3016
3017        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3018        if !edits.is_empty() {
3019            self.subscriptions.publish(edits);
3020        }
3021        cx.emit(Event::Edited {
3022            edited_buffer: None,
3023        });
3024        cx.emit(Event::ExcerptsExpanded { ids });
3025        cx.notify();
3026    }
3027
3028    #[ztracing::instrument(skip_all)]
3029    fn sync(&self, cx: &App) {
3030        let changed = self.buffer_changed_since_sync.replace(false);
3031        if !changed {
3032            return;
3033        }
3034        let edits = Self::sync_from_buffer_changes(
3035            &mut self.snapshot.borrow_mut(),
3036            &self.buffers,
3037            &self.diffs,
3038            cx,
3039        );
3040        if !edits.is_empty() {
3041            self.subscriptions.publish(edits);
3042        }
3043    }
3044
3045    fn sync_mut(&mut self, cx: &App) {
3046        let changed = self.buffer_changed_since_sync.replace(false);
3047        if !changed {
3048            return;
3049        }
3050        let edits =
3051            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3052
3053        if !edits.is_empty() {
3054            self.subscriptions.publish(edits);
3055        }
3056    }
3057
3058    fn sync_from_buffer_changes(
3059        snapshot: &mut MultiBufferSnapshot,
3060        buffers: &BTreeMap<BufferId, BufferState>,
3061        diffs: &HashMap<BufferId, DiffState>,
3062        cx: &App,
3063    ) -> Vec<Edit<MultiBufferOffset>> {
3064        let MultiBufferSnapshot {
3065            excerpts,
3066            buffer_locators: _,
3067            diffs: buffer_diff,
3068            diff_transforms: _,
3069            non_text_state_update_count,
3070            edit_count,
3071            is_dirty,
3072            has_deleted_file,
3073            has_conflict,
3074            has_inverted_diff: _,
3075            singleton: _,
3076            excerpt_ids: _,
3077            replaced_excerpts: _,
3078            trailing_excerpt_update_count: _,
3079            all_diff_hunks_expanded: _,
3080            show_deleted_hunks: _,
3081            use_extended_diff_range: _,
3082            show_headers: _,
3083        } = snapshot;
3084        *is_dirty = false;
3085        *has_deleted_file = false;
3086        *has_conflict = false;
3087
3088        if !diffs.is_empty() {
3089            let mut diffs_to_add = Vec::new();
3090            for (id, diff) in diffs {
3091                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3092                // and use the diff hunk base text ranges to compute diff transforms.
3093                // Those base text ranges are usize, so make sure if the base text changed
3094                // we also update the diff snapshot so that we don't use stale offsets
3095                if buffer_diff.get(id).is_none_or(|existing_diff| {
3096                    if !existing_diff.is_inverted {
3097                        return false;
3098                    }
3099                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3100                    base_text.remote_id() != existing_diff.base_text().remote_id()
3101                        || base_text
3102                            .version()
3103                            .changed_since(existing_diff.base_text().version())
3104                }) {
3105                    if diffs_to_add.capacity() == 0 {
3106                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3107                        // meaning re-allocations will be fairly expensive
3108                        diffs_to_add.reserve(diffs.len());
3109                    }
3110                    diffs_to_add.push((*id, diff.snapshot(cx)));
3111                }
3112            }
3113            buffer_diff.extend(diffs_to_add);
3114        }
3115
3116        let mut excerpts_to_edit = Vec::new();
3117        let mut non_text_state_updated = false;
3118        let mut edited = false;
3119        for buffer_state in buffers.values() {
3120            let buffer = buffer_state.buffer.read(cx);
3121            let version = buffer.version();
3122            let non_text_state_update_count = buffer.non_text_state_update_count();
3123
3124            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3125            let buffer_non_text_state_updated =
3126                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3127            if buffer_edited || buffer_non_text_state_updated {
3128                *buffer_state.last_version.borrow_mut() = version;
3129                buffer_state
3130                    .last_non_text_state_update_count
3131                    .set(non_text_state_update_count);
3132                excerpts_to_edit.extend(
3133                    buffer_state
3134                        .excerpts
3135                        .iter()
3136                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3137                );
3138            }
3139
3140            edited |= buffer_edited;
3141            non_text_state_updated |= buffer_non_text_state_updated;
3142            *is_dirty |= buffer.is_dirty();
3143            *has_deleted_file |= buffer
3144                .file()
3145                .is_some_and(|file| file.disk_state().is_deleted());
3146            *has_conflict |= buffer.has_conflict();
3147        }
3148        if edited {
3149            *edit_count += 1;
3150        }
3151        if non_text_state_updated {
3152            *non_text_state_update_count += 1;
3153        }
3154
3155        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3156
3157        let mut edits = Vec::new();
3158        let mut new_excerpts = SumTree::default();
3159        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3160
3161        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3162            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3163            let old_excerpt = cursor.item().unwrap();
3164            let buffer = buffer.read(cx);
3165            let buffer_id = buffer.remote_id();
3166            let mut new_excerpt;
3167            if buffer_edited {
3168                edits.extend(
3169                    buffer
3170                        .edits_since_in_range::<usize>(
3171                            old_excerpt.buffer.version(),
3172                            old_excerpt.range.context.clone(),
3173                        )
3174                        .map(|edit| {
3175                            let excerpt_old_start = cursor.start().1;
3176                            let excerpt_new_start =
3177                                ExcerptDimension(new_excerpts.summary().text.len);
3178                            let old_start = excerpt_old_start + edit.old.start;
3179                            let old_end = excerpt_old_start + edit.old.end;
3180                            let new_start = excerpt_new_start + edit.new.start;
3181                            let new_end = excerpt_new_start + edit.new.end;
3182                            Edit {
3183                                old: old_start..old_end,
3184                                new: new_start..new_end,
3185                            }
3186                        }),
3187                );
3188
3189                new_excerpt = Excerpt::new(
3190                    old_excerpt.id,
3191                    locator.clone(),
3192                    buffer_id,
3193                    Arc::new(buffer.snapshot()),
3194                    old_excerpt.range.clone(),
3195                    old_excerpt.has_trailing_newline,
3196                );
3197            } else {
3198                new_excerpt = old_excerpt.clone();
3199                new_excerpt.buffer = Arc::new(buffer.snapshot());
3200            }
3201
3202            new_excerpts.push(new_excerpt, ());
3203            cursor.next();
3204        }
3205        new_excerpts.append(cursor.suffix(), ());
3206
3207        drop(cursor);
3208        *excerpts = new_excerpts;
3209
3210        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3211    }
3212
3213    fn sync_diff_transforms(
3214        snapshot: &mut MultiBufferSnapshot,
3215        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3216        change_kind: DiffChangeKind,
3217    ) -> Vec<Edit<MultiBufferOffset>> {
3218        if excerpt_edits.is_empty() {
3219            return vec![];
3220        }
3221
3222        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3223        let mut old_diff_transforms = snapshot
3224            .diff_transforms
3225            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3226        let mut new_diff_transforms = SumTree::default();
3227        let mut old_expanded_hunks = HashSet::default();
3228        let mut output_edits = Vec::new();
3229        let mut output_delta = 0_isize;
3230        let mut at_transform_boundary = true;
3231        let mut end_of_current_insert = None;
3232
3233        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3234        while let Some(edit) = excerpt_edits.next() {
3235            excerpts.seek_forward(&edit.new.start, Bias::Right);
3236            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3237                excerpts.prev();
3238            }
3239
3240            // Keep any transforms that are before the edit.
3241            if at_transform_boundary {
3242                at_transform_boundary = false;
3243                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3244                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3245                if let Some(transform) = old_diff_transforms.item()
3246                    && old_diff_transforms.end().0 == edit.old.start
3247                    && old_diff_transforms.start().0 < edit.old.start
3248                {
3249                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3250                    old_diff_transforms.next();
3251                }
3252            }
3253
3254            // Compute the start of the edit in output coordinates.
3255            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3256            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3257            let edit_new_start =
3258                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3259
3260            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3261                &edit,
3262                &mut excerpts,
3263                &mut old_diff_transforms,
3264                &mut new_diff_transforms,
3265                &mut end_of_current_insert,
3266                &mut old_expanded_hunks,
3267                snapshot,
3268                change_kind,
3269            );
3270
3271            // Compute the end of the edit in output coordinates.
3272            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3273            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3274            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3275            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3276            let output_edit = Edit {
3277                old: edit_old_start..edit_old_end,
3278                new: edit_new_start..edit_new_end,
3279            };
3280
3281            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3282            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3283            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3284                output_edits.push(output_edit);
3285            }
3286
3287            // If this is the last edit that intersects the current diff transform,
3288            // then recreate the content up to the end of this transform, to prepare
3289            // for reusing additional slices of the old transforms.
3290            if excerpt_edits
3291                .peek()
3292                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3293            {
3294                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3295                    && match old_diff_transforms.item() {
3296                        Some(DiffTransform::BufferContent {
3297                            inserted_hunk_info: Some(hunk),
3298                            ..
3299                        }) => excerpts.item().is_some_and(|excerpt| {
3300                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3301                                && diff.is_inverted
3302                            {
3303                                return true;
3304                            }
3305                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3306                        }),
3307                        _ => true,
3308                    };
3309
3310                let mut excerpt_offset = edit.new.end;
3311                if !keep_next_old_transform {
3312                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3313                    old_diff_transforms.next();
3314                }
3315
3316                old_expanded_hunks.clear();
3317                Self::push_buffer_content_transform(
3318                    snapshot,
3319                    &mut new_diff_transforms,
3320                    excerpt_offset,
3321                    end_of_current_insert,
3322                );
3323                at_transform_boundary = true;
3324            }
3325        }
3326
3327        // Keep any transforms that are after the last edit.
3328        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3329
3330        // Ensure there's always at least one buffer content transform.
3331        if new_diff_transforms.is_empty() {
3332            new_diff_transforms.push(
3333                DiffTransform::BufferContent {
3334                    summary: Default::default(),
3335                    inserted_hunk_info: None,
3336                },
3337                (),
3338            );
3339        }
3340
3341        drop(old_diff_transforms);
3342        drop(excerpts);
3343        snapshot.diff_transforms = new_diff_transforms;
3344        snapshot.edit_count += 1;
3345
3346        #[cfg(any(test, feature = "test-support"))]
3347        snapshot.check_invariants();
3348        output_edits
3349    }
3350
3351    fn recompute_diff_transforms_for_edit(
3352        edit: &Edit<ExcerptOffset>,
3353        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3354        old_diff_transforms: &mut Cursor<
3355            DiffTransform,
3356            Dimensions<ExcerptOffset, MultiBufferOffset>,
3357        >,
3358        new_diff_transforms: &mut SumTree<DiffTransform>,
3359        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3360        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3361        snapshot: &MultiBufferSnapshot,
3362        change_kind: DiffChangeKind,
3363    ) -> bool {
3364        log::trace!(
3365            "recomputing diff transform for edit {:?} => {:?}",
3366            edit.old.start..edit.old.end,
3367            edit.new.start..edit.new.end
3368        );
3369
3370        // Record which hunks were previously expanded.
3371        while let Some(item) = old_diff_transforms.item() {
3372            if let Some(hunk_info) = item.hunk_info() {
3373                log::trace!(
3374                    "previously expanded hunk at {:?}",
3375                    old_diff_transforms.start()
3376                );
3377                old_expanded_hunks.insert(hunk_info);
3378            }
3379            if old_diff_transforms.end().0 > edit.old.end {
3380                break;
3381            }
3382            old_diff_transforms.next();
3383        }
3384
3385        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3386        // For inverted diffs, hunks are always shown, so we can't skip this.
3387        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3388        if old_expanded_hunks.is_empty()
3389            && change_kind == DiffChangeKind::BufferEdited
3390            && !all_diff_hunks_expanded
3391            && !snapshot.has_inverted_diff
3392        {
3393            return false;
3394        }
3395
3396        // Visit each excerpt that intersects the edit.
3397        let mut did_expand_hunks = false;
3398        while let Some(excerpt) = excerpts.item() {
3399            // Recompute the expanded hunks in the portion of the excerpt that
3400            // intersects the edit.
3401            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3402                let buffer = &excerpt.buffer;
3403                let excerpt_start = *excerpts.start();
3404                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3405                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3406                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3407                let edit_buffer_start =
3408                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3409                let edit_buffer_end =
3410                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3411                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3412
3413                if diff.is_inverted {
3414                    for hunk in diff.hunks_intersecting_base_text_range(
3415                        edit_buffer_start..edit_buffer_end,
3416                        diff.original_buffer_snapshot(),
3417                    ) {
3418                        did_expand_hunks = true;
3419                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3420                        if hunk_buffer_range.start < excerpt_buffer_start {
3421                            log::trace!("skipping hunk that starts before excerpt");
3422                            continue;
3423                        }
3424                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3425                        let hunk_excerpt_start = excerpt_start
3426                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3427                        let hunk_excerpt_end = excerpt_end
3428                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3429                        Self::push_buffer_content_transform(
3430                            snapshot,
3431                            new_diff_transforms,
3432                            hunk_excerpt_start,
3433                            *end_of_current_insert,
3434                        );
3435                        if !hunk_buffer_range.is_empty() {
3436                            let hunk_info = DiffTransformHunkInfo {
3437                                excerpt_id: excerpt.id,
3438                                hunk_start_anchor: hunk.buffer_range.start,
3439                                hunk_secondary_status: hunk.secondary_status,
3440                                is_logically_deleted: true,
3441                            };
3442                            *end_of_current_insert =
3443                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3444                        }
3445                    }
3446                } else {
3447                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3448                        ..buffer.anchor_after(edit_buffer_end);
3449                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3450                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3451                            continue;
3452                        }
3453
3454                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3455                        if hunk_buffer_range.start < excerpt_buffer_start {
3456                            log::trace!("skipping hunk that starts before excerpt");
3457                            continue;
3458                        }
3459
3460                        let hunk_info = DiffTransformHunkInfo {
3461                            excerpt_id: excerpt.id,
3462                            hunk_start_anchor: hunk.buffer_range.start,
3463                            hunk_secondary_status: hunk.secondary_status,
3464                            is_logically_deleted: false,
3465                        };
3466
3467                        let hunk_excerpt_start = excerpt_start
3468                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3469                        let hunk_excerpt_end = excerpt_end
3470                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3471
3472                        Self::push_buffer_content_transform(
3473                            snapshot,
3474                            new_diff_transforms,
3475                            hunk_excerpt_start,
3476                            *end_of_current_insert,
3477                        );
3478
3479                        // For every existing hunk, determine if it was previously expanded
3480                        // and if it should currently be expanded.
3481                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3482                        let should_expand_hunk = match &change_kind {
3483                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3484                                was_previously_expanded || all_diff_hunks_expanded
3485                            }
3486                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3487                                let intersects = hunk_buffer_range.is_empty()
3488                                    || hunk_buffer_range.end > edit_buffer_start;
3489                                if *expand {
3490                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3491                                } else {
3492                                    !intersects
3493                                        && (was_previously_expanded || all_diff_hunks_expanded)
3494                                }
3495                            }
3496                            _ => was_previously_expanded || all_diff_hunks_expanded,
3497                        };
3498
3499                        if should_expand_hunk {
3500                            did_expand_hunks = true;
3501                            log::trace!(
3502                                "expanding hunk {:?}, excerpt:{:?}",
3503                                hunk_excerpt_start..hunk_excerpt_end,
3504                                excerpt.id
3505                            );
3506
3507                            if !hunk.diff_base_byte_range.is_empty()
3508                                && hunk_buffer_range.start >= edit_buffer_start
3509                                && hunk_buffer_range.start <= excerpt_buffer_end
3510                                && snapshot.show_deleted_hunks
3511                            {
3512                                let base_text = diff.base_text();
3513                                let mut text_cursor =
3514                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3515                                let mut base_text_summary = text_cursor
3516                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3517
3518                                let mut has_trailing_newline = false;
3519                                if base_text_summary.last_line_chars > 0 {
3520                                    base_text_summary += TextSummary::newline();
3521                                    has_trailing_newline = true;
3522                                }
3523
3524                                new_diff_transforms.push(
3525                                    DiffTransform::DeletedHunk {
3526                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3527                                        summary: base_text_summary,
3528                                        buffer_id: excerpt.buffer_id,
3529                                        hunk_info,
3530                                        has_trailing_newline,
3531                                    },
3532                                    (),
3533                                );
3534                            }
3535
3536                            if !hunk_buffer_range.is_empty() {
3537                                *end_of_current_insert =
3538                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3539                            }
3540                        }
3541                    }
3542                }
3543            }
3544
3545            if excerpts.end() <= edit.new.end {
3546                excerpts.next();
3547            } else {
3548                break;
3549            }
3550        }
3551
3552        did_expand_hunks || !old_expanded_hunks.is_empty()
3553    }
3554
3555    fn append_diff_transforms(
3556        new_transforms: &mut SumTree<DiffTransform>,
3557        subtree: SumTree<DiffTransform>,
3558    ) {
3559        if let Some(DiffTransform::BufferContent {
3560            inserted_hunk_info,
3561            summary,
3562        }) = subtree.first()
3563            && Self::extend_last_buffer_content_transform(
3564                new_transforms,
3565                *inserted_hunk_info,
3566                *summary,
3567            )
3568        {
3569            let mut cursor = subtree.cursor::<()>(());
3570            cursor.next();
3571            cursor.next();
3572            new_transforms.append(cursor.suffix(), ());
3573            return;
3574        }
3575        new_transforms.append(subtree, ());
3576    }
3577
3578    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3579        if let DiffTransform::BufferContent {
3580            inserted_hunk_info: inserted_hunk_anchor,
3581            summary,
3582        } = transform
3583            && Self::extend_last_buffer_content_transform(
3584                new_transforms,
3585                inserted_hunk_anchor,
3586                summary,
3587            )
3588        {
3589            return;
3590        }
3591        new_transforms.push(transform, ());
3592    }
3593
3594    fn push_buffer_content_transform(
3595        old_snapshot: &MultiBufferSnapshot,
3596        new_transforms: &mut SumTree<DiffTransform>,
3597        end_offset: ExcerptOffset,
3598        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3599    ) {
3600        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3601            (end_offset.min(insertion_end_offset), Some(hunk_info))
3602        });
3603        let unchanged_region = [(end_offset, None)];
3604
3605        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3606        {
3607            let start_offset = new_transforms.summary().excerpt_len();
3608            if end_offset <= start_offset {
3609                continue;
3610            }
3611            let summary_to_add = old_snapshot
3612                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3613
3614            if !Self::extend_last_buffer_content_transform(
3615                new_transforms,
3616                inserted_hunk_info,
3617                summary_to_add,
3618            ) {
3619                new_transforms.push(
3620                    DiffTransform::BufferContent {
3621                        summary: summary_to_add,
3622                        inserted_hunk_info,
3623                    },
3624                    (),
3625                )
3626            }
3627        }
3628    }
3629
3630    fn extend_last_buffer_content_transform(
3631        new_transforms: &mut SumTree<DiffTransform>,
3632        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3633        summary_to_add: MBTextSummary,
3634    ) -> bool {
3635        let mut did_extend = false;
3636        new_transforms.update_last(
3637            |last_transform| {
3638                if let DiffTransform::BufferContent {
3639                    summary,
3640                    inserted_hunk_info: inserted_hunk_anchor,
3641                } = last_transform
3642                    && *inserted_hunk_anchor == new_inserted_hunk_info
3643                {
3644                    *summary += summary_to_add;
3645                    did_extend = true;
3646                }
3647            },
3648            (),
3649        );
3650        did_extend
3651    }
3652
3653    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3654        let snapshot = self.snapshot(cx);
3655        let excerpt_id = range.end.excerpt_id;
3656        let point_range = range.to_point(&snapshot);
3657        let expand = !self.single_hunk_is_expanded(range, cx);
3658        let edits =
3659            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3660        if !edits.is_empty() {
3661            self.subscriptions.publish(edits);
3662        }
3663        cx.emit(Event::DiffHunksToggled);
3664        cx.emit(Event::Edited {
3665            edited_buffer: None,
3666        });
3667    }
3668}
3669
3670fn build_excerpt_ranges(
3671    ranges: impl IntoIterator<Item = Range<Point>>,
3672    context_line_count: u32,
3673    buffer_snapshot: &BufferSnapshot,
3674) -> Vec<ExcerptRange<Point>> {
3675    ranges
3676        .into_iter()
3677        .map(|range| {
3678            let start_row = range.start.row.saturating_sub(context_line_count);
3679            let start = Point::new(start_row, 0);
3680            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3681            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3682            ExcerptRange {
3683                context: start..end,
3684                primary: range,
3685            }
3686        })
3687        .collect()
3688}
3689
3690#[cfg(any(test, feature = "test-support"))]
3691impl MultiBuffer {
3692    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3693        let buffer = cx.new(|cx| Buffer::local(text, cx));
3694        cx.new(|cx| Self::singleton(buffer, cx))
3695    }
3696
3697    pub fn build_multi<const COUNT: usize>(
3698        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3699        cx: &mut gpui::App,
3700    ) -> Entity<Self> {
3701        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3702        for (text, ranges) in excerpts {
3703            let buffer = cx.new(|cx| Buffer::local(text, cx));
3704            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3705            multi.update(cx, |multi, cx| {
3706                multi.push_excerpts(buffer, excerpt_ranges, cx)
3707            });
3708        }
3709
3710        multi
3711    }
3712
3713    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3714        cx.new(|cx| Self::singleton(buffer, cx))
3715    }
3716
3717    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3718        cx.new(|cx| {
3719            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3720            let mutation_count = rng.random_range(1..=5);
3721            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3722            multibuffer
3723        })
3724    }
3725
3726    pub fn randomly_edit(
3727        &mut self,
3728        rng: &mut impl rand::Rng,
3729        edit_count: usize,
3730        cx: &mut Context<Self>,
3731    ) {
3732        use util::RandomCharIter;
3733
3734        let snapshot = self.read(cx);
3735        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3736        let mut last_end = None;
3737        for _ in 0..edit_count {
3738            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3739                break;
3740            }
3741
3742            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3743            let end =
3744                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3745            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3746            last_end = Some(end);
3747
3748            let mut range = start..end;
3749            if rng.random_bool(0.2) {
3750                mem::swap(&mut range.start, &mut range.end);
3751            }
3752
3753            let new_text_len = rng.random_range(0..10);
3754            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3755
3756            edits.push((range, new_text.into()));
3757        }
3758        log::info!("mutating multi-buffer with {:?}", edits);
3759        drop(snapshot);
3760
3761        self.edit(edits, None, cx);
3762    }
3763
3764    pub fn randomly_edit_excerpts(
3765        &mut self,
3766        rng: &mut impl rand::Rng,
3767        mutation_count: usize,
3768        cx: &mut Context<Self>,
3769    ) {
3770        use rand::prelude::*;
3771        use std::env;
3772        use util::RandomCharIter;
3773
3774        let max_excerpts = env::var("MAX_EXCERPTS")
3775            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3776            .unwrap_or(5);
3777
3778        let mut buffers = Vec::new();
3779        for _ in 0..mutation_count {
3780            if rng.random_bool(0.05) {
3781                log::info!("Clearing multi-buffer");
3782                self.clear(cx);
3783                continue;
3784            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3785                let ids = self.excerpt_ids();
3786                let mut excerpts = HashSet::default();
3787                for _ in 0..rng.random_range(0..ids.len()) {
3788                    excerpts.extend(ids.choose(rng).copied());
3789                }
3790
3791                let line_count = rng.random_range(0..5);
3792
3793                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3794
3795                self.expand_excerpts(
3796                    excerpts.iter().cloned(),
3797                    line_count,
3798                    ExpandExcerptDirection::UpAndDown,
3799                    cx,
3800                );
3801                continue;
3802            }
3803
3804            let excerpt_ids = self.excerpt_ids();
3805            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3806                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3807                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3808                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3809                    let buffer = buffers.last().unwrap().read(cx);
3810                    log::info!(
3811                        "Creating new buffer {} with text: {:?}",
3812                        buffer.remote_id(),
3813                        buffer.text()
3814                    );
3815                    buffers.last().unwrap().clone()
3816                } else {
3817                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3818                };
3819
3820                let buffer = buffer_handle.read(cx);
3821                let buffer_text = buffer.text();
3822                let ranges = (0..rng.random_range(0..5))
3823                    .map(|_| {
3824                        let end_ix =
3825                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3826                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3827                        ExcerptRange::new(start_ix..end_ix)
3828                    })
3829                    .collect::<Vec<_>>();
3830                log::info!(
3831                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3832                    buffer_handle.read(cx).remote_id(),
3833                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3834                    ranges
3835                        .iter()
3836                        .map(|r| &buffer_text[r.context.clone()])
3837                        .collect::<Vec<_>>()
3838                );
3839
3840                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3841                log::info!("Inserted with ids: {:?}", excerpt_id);
3842            } else {
3843                let remove_count = rng.random_range(1..=excerpt_ids.len());
3844                let mut excerpts_to_remove = excerpt_ids
3845                    .choose_multiple(rng, remove_count)
3846                    .cloned()
3847                    .collect::<Vec<_>>();
3848                let snapshot = self.snapshot.borrow();
3849                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3850                drop(snapshot);
3851                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3852                self.remove_excerpts(excerpts_to_remove, cx);
3853            }
3854        }
3855    }
3856
3857    pub fn randomly_mutate(
3858        &mut self,
3859        rng: &mut impl rand::Rng,
3860        mutation_count: usize,
3861        cx: &mut Context<Self>,
3862    ) {
3863        use rand::prelude::*;
3864
3865        if rng.random_bool(0.7) || self.singleton {
3866            let buffer = self
3867                .buffers
3868                .values()
3869                .choose(rng)
3870                .map(|state| state.buffer.clone());
3871
3872            if let Some(buffer) = buffer {
3873                buffer.update(cx, |buffer, cx| {
3874                    if rng.random() {
3875                        buffer.randomly_edit(rng, mutation_count, cx);
3876                    } else {
3877                        buffer.randomly_undo_redo(rng, cx);
3878                    }
3879                });
3880            } else {
3881                self.randomly_edit(rng, mutation_count, cx);
3882            }
3883        } else {
3884            self.randomly_edit_excerpts(rng, mutation_count, cx);
3885        }
3886
3887        self.check_invariants(cx);
3888    }
3889
3890    fn check_invariants(&self, cx: &App) {
3891        self.read(cx).check_invariants();
3892    }
3893}
3894
3895impl EventEmitter<Event> for MultiBuffer {}
3896
3897impl MultiBufferSnapshot {
3898    pub fn text(&self) -> String {
3899        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3900            .map(|chunk| chunk.text)
3901            .collect()
3902    }
3903
3904    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3905        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3906            .flat_map(|c| c.chars().rev())
3907    }
3908
3909    fn reversed_chunks_in_range(
3910        &self,
3911        range: Range<MultiBufferOffset>,
3912    ) -> ReversedMultiBufferChunks<'_> {
3913        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3914        cursor.seek(&range.end);
3915        let current_chunks = cursor.region().as_ref().map(|region| {
3916            let start_overshoot = range.start.saturating_sub(region.range.start);
3917            let end_overshoot = range.end - region.range.start;
3918            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3919            let start = region.buffer_range.start + start_overshoot;
3920            region.buffer.reversed_chunks_in_range(start..end)
3921        });
3922        ReversedMultiBufferChunks {
3923            cursor,
3924            current_chunks,
3925            start: range.start,
3926            offset: range.end,
3927        }
3928    }
3929
3930    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3931        let offset = position.to_offset(self);
3932        self.text_for_range(offset..self.len())
3933            .flat_map(|chunk| chunk.chars())
3934    }
3935
3936    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3937        self.chunks(range, false).map(|chunk| chunk.text)
3938    }
3939
3940    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3941        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3942            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3943    }
3944
3945    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3946    where
3947        T: ToOffset,
3948    {
3949        let position = position.to_offset(self);
3950        position == self.clip_offset(position, Bias::Left)
3951            && self
3952                .bytes_in_range(position..self.len())
3953                .flatten()
3954                .copied()
3955                .take(needle.len())
3956                .eq(needle.bytes())
3957    }
3958
3959    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3960        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3961    }
3962
3963    pub fn diff_hunks_in_range<T: ToPoint>(
3964        &self,
3965        range: Range<T>,
3966    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3967        let query_range = range.start.to_point(self)..range.end.to_point(self);
3968        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3969            let diff = self.diffs.get(&buffer.remote_id())?;
3970            let iter = if diff.is_inverted {
3971                let buffer_start = buffer.point_to_offset(buffer_range.start);
3972                let buffer_end = buffer.point_to_offset(buffer_range.end);
3973                itertools::Either::Left(
3974                    diff.hunks_intersecting_base_text_range(
3975                        buffer_start..buffer_end,
3976                        diff.original_buffer_snapshot(),
3977                    )
3978                    .map(move |hunk| (hunk, buffer, true)),
3979                )
3980            } else {
3981                let buffer_start = buffer.anchor_before(buffer_range.start);
3982                let buffer_end = buffer.anchor_after(buffer_range.end);
3983                itertools::Either::Right(
3984                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3985                        .map(move |hunk| (hunk, buffer, false)),
3986                )
3987            };
3988            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3989                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3990                    return None;
3991                }
3992                let range = if is_inverted {
3993                    hunk.diff_base_byte_range.to_point(&buffer)
3994                } else {
3995                    hunk.range.clone()
3996                };
3997                Some((range, (hunk, is_inverted)))
3998            }))
3999        })
4000        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4001            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4002            {
4003                return None;
4004            }
4005            let end_row = if range.end.column == 0 {
4006                range.end.row
4007            } else {
4008                range.end.row + 1
4009            };
4010
4011            let word_diffs =
4012                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4013                    .then(|| {
4014                        let mut word_diffs = Vec::new();
4015
4016                        if self.show_deleted_hunks || is_inverted {
4017                            let hunk_start_offset = if is_inverted {
4018                                Anchor::in_buffer(
4019                                    excerpt.id,
4020                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4021                                )
4022                                .to_offset(self)
4023                            } else {
4024                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4025                                    .to_offset(self)
4026                            };
4027
4028                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4029                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4030                            }));
4031                        }
4032
4033                        if !is_inverted {
4034                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4035                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4036                            }));
4037                        }
4038                        word_diffs
4039                    })
4040                    .unwrap_or_default();
4041
4042            let buffer_range = if is_inverted {
4043                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4044                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4045            } else {
4046                hunk.buffer_range.clone()
4047            };
4048            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4049                DiffHunkStatusKind::Deleted
4050            } else if hunk.diff_base_byte_range.is_empty() {
4051                DiffHunkStatusKind::Added
4052            } else {
4053                DiffHunkStatusKind::Modified
4054            };
4055            Some(MultiBufferDiffHunk {
4056                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4057                buffer_id: excerpt.buffer_id,
4058                excerpt_id: excerpt.id,
4059                buffer_range,
4060                word_diffs,
4061                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4062                    ..BufferOffset(hunk.diff_base_byte_range.end),
4063                status: DiffHunkStatus {
4064                    kind: status_kind,
4065                    secondary: hunk.secondary_status,
4066                },
4067            })
4068        })
4069    }
4070
4071    fn excerpts_for_range<T: ToOffset>(
4072        &self,
4073        range: Range<T>,
4074    ) -> impl Iterator<Item = &Excerpt> + '_ {
4075        let range = range.start.to_offset(self)..range.end.to_offset(self);
4076        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4077        cursor.seek(&range.start);
4078        std::iter::from_fn(move || {
4079            let region = cursor.region()?;
4080            if region.range.start > range.end
4081                || region.range.start == range.end && region.range.start > range.start
4082            {
4083                return None;
4084            }
4085            let excerpt = region.excerpt;
4086            cursor.next_excerpt_forwards();
4087            Some(excerpt)
4088        })
4089    }
4090
4091    pub fn excerpt_ids_for_range<T: ToOffset>(
4092        &self,
4093        range: Range<T>,
4094    ) -> impl Iterator<Item = ExcerptId> + '_ {
4095        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4096    }
4097
4098    pub fn buffer_ids_for_range<T: ToOffset>(
4099        &self,
4100        range: Range<T>,
4101    ) -> impl Iterator<Item = BufferId> + '_ {
4102        self.excerpts_for_range(range)
4103            .map(|excerpt| excerpt.buffer_id)
4104    }
4105
4106    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4107    ///
4108    /// The passed in anchors must be ordered.
4109    pub fn text_anchors_to_visible_anchors(
4110        &self,
4111        anchors: impl IntoIterator<Item = text::Anchor>,
4112    ) -> Vec<Option<Anchor>> {
4113        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4114        let mut anchors = anchors.into_iter().peekable();
4115        let mut result = Vec::new();
4116        'anchors: while let Some(anchor) = anchors.peek() {
4117            let Some(buffer_id) = anchor.buffer_id else {
4118                anchors.next();
4119                result.push(None);
4120                continue 'anchors;
4121            };
4122            let mut same_buffer_anchors =
4123                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4124
4125            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4126                let Some(mut next) = same_buffer_anchors.next() else {
4127                    continue 'anchors;
4128                };
4129                'excerpts: for locator in locators.iter() {
4130                    if cursor.seek_forward(&Some(locator), Bias::Left)
4131                        && let Some(excerpt) = cursor.item()
4132                    {
4133                        loop {
4134                            // anchor is before the first excerpt
4135                            if excerpt
4136                                .range
4137                                .context
4138                                .start
4139                                .cmp(&next, &excerpt.buffer)
4140                                .is_gt()
4141                            {
4142                                // so we skip it and try the next anchor
4143                                result.push(None);
4144                                match same_buffer_anchors.next() {
4145                                    Some(anchor) => next = anchor,
4146                                    None => continue 'anchors,
4147                                }
4148                            // anchor is within the excerpt
4149                            } else if excerpt
4150                                .range
4151                                .context
4152                                .end
4153                                .cmp(&next, &excerpt.buffer)
4154                                .is_ge()
4155                            {
4156                                // record it and all following anchors that are within
4157                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4158                                result.extend(
4159                                    same_buffer_anchors
4160                                        .peeking_take_while(|a| {
4161                                            excerpt
4162                                                .range
4163                                                .context
4164                                                .end
4165                                                .cmp(a, &excerpt.buffer)
4166                                                .is_ge()
4167                                        })
4168                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4169                                );
4170                                match same_buffer_anchors.next() {
4171                                    Some(anchor) => next = anchor,
4172                                    None => continue 'anchors,
4173                                }
4174                            // anchor is after the excerpt, try the next one
4175                            } else {
4176                                continue 'excerpts;
4177                            }
4178                        }
4179                    }
4180                }
4181                // account for `next`
4182                result.push(None);
4183            }
4184            result.extend(same_buffer_anchors.map(|_| None));
4185        }
4186
4187        result
4188    }
4189
4190    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4191        &self,
4192        ranges: impl Iterator<Item = Range<T>>,
4193    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4194        ranges.flat_map(|range| {
4195            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4196                .into_iter()
4197        })
4198    }
4199
4200    pub fn range_to_buffer_ranges<R, T>(
4201        &self,
4202        range: R,
4203    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4204    where
4205        R: RangeBounds<T>,
4206        T: ToOffset,
4207    {
4208        self.range_to_buffer_ranges_with_context(range)
4209            .into_iter()
4210            .map(|(buffer, range, id, _context)| (buffer, range, id))
4211            .collect()
4212    }
4213
4214    pub fn range_to_buffer_ranges_with_context<R, T>(
4215        &self,
4216        range: R,
4217    ) -> Vec<(
4218        &BufferSnapshot,
4219        Range<BufferOffset>,
4220        ExcerptId,
4221        Range<text::Anchor>,
4222    )>
4223    where
4224        R: RangeBounds<T>,
4225        T: ToOffset,
4226    {
4227        let start = match range.start_bound() {
4228            Bound::Included(start) => start.to_offset(self),
4229            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4230            Bound::Unbounded => MultiBufferOffset::ZERO,
4231        };
4232        let end_bound = match range.end_bound() {
4233            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4234            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4235            Bound::Unbounded => Bound::Unbounded,
4236        };
4237        let bounds = (Bound::Included(start), end_bound);
4238
4239        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4240        cursor.seek(&start);
4241
4242        let mut result: Vec<(
4243            &BufferSnapshot,
4244            Range<BufferOffset>,
4245            ExcerptId,
4246            Range<text::Anchor>,
4247        )> = Vec::new();
4248        while let Some(region) = cursor.region() {
4249            let dominated_by_end_bound = match end_bound {
4250                Bound::Included(end) => region.range.start > end,
4251                Bound::Excluded(end) => region.range.start >= end,
4252                Bound::Unbounded => false,
4253            };
4254            if dominated_by_end_bound {
4255                break;
4256            }
4257            if region.is_main_buffer {
4258                let start_overshoot = start.saturating_sub(region.range.start);
4259                let end_offset = match end_bound {
4260                    Bound::Included(end) | Bound::Excluded(end) => end,
4261                    Bound::Unbounded => region.range.end,
4262                };
4263                let end_overshoot = end_offset.saturating_sub(region.range.start);
4264                let start = region
4265                    .buffer_range
4266                    .end
4267                    .min(region.buffer_range.start + start_overshoot);
4268                let end = region
4269                    .buffer_range
4270                    .end
4271                    .min(region.buffer_range.start + end_overshoot);
4272                let context = region.excerpt.range.context.clone();
4273                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4274                    *excerpt_id == region.excerpt.id && prev_range.end == start
4275                }) {
4276                    prev.1.end = end;
4277                } else {
4278                    result.push((region.buffer, start..end, region.excerpt.id, context));
4279                }
4280            }
4281            cursor.next();
4282        }
4283
4284        if let Some(excerpt) = cursor.excerpt() {
4285            let dominated_by_prev_excerpt =
4286                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4287            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4288                let excerpt_position = self.len();
4289                if bounds.contains(&excerpt_position) {
4290                    let buffer_offset =
4291                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4292                    let context = excerpt.range.context.clone();
4293                    result.push((
4294                        &excerpt.buffer,
4295                        buffer_offset..buffer_offset,
4296                        excerpt.id,
4297                        context,
4298                    ));
4299                }
4300            }
4301        }
4302
4303        result
4304    }
4305
4306    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4307        &self,
4308        range: Range<T>,
4309    ) -> impl Iterator<
4310        Item = (
4311            &BufferSnapshot,
4312            Range<BufferOffset>,
4313            ExcerptId,
4314            Option<Anchor>,
4315        ),
4316    > + '_ {
4317        let start = range.start.to_offset(self);
4318        let end = range.end.to_offset(self);
4319
4320        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4321        cursor.seek(&start);
4322
4323        std::iter::from_fn(move || {
4324            let region = cursor.region()?;
4325            if region.range.start > end {
4326                return None;
4327            }
4328            let start_overshoot = start.saturating_sub(region.range.start);
4329            let end_overshoot = end.saturating_sub(region.range.start);
4330            let start = region
4331                .buffer_range
4332                .end
4333                .min(region.buffer_range.start + start_overshoot);
4334            let end = region
4335                .buffer_range
4336                .end
4337                .min(region.buffer_range.start + end_overshoot);
4338
4339            let region_excerpt_id = region.excerpt.id;
4340            let deleted_hunk_anchor = if region.is_main_buffer {
4341                None
4342            } else {
4343                Some(self.anchor_before(region.range.start))
4344            };
4345            let result = (
4346                region.buffer,
4347                start..end,
4348                region_excerpt_id,
4349                deleted_hunk_anchor,
4350            );
4351            cursor.next();
4352            Some(result)
4353        })
4354    }
4355
4356    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4357    /// coordinates.
4358    ///
4359    /// The given callback will be called for every excerpt intersecting the given range. It will
4360    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4361    /// The callback should return an iterator of metadata items from that buffer, each paired
4362    /// with a buffer range.
4363    ///
4364    /// The returned iterator yields each of these metadata items, paired with its range in
4365    /// multi-buffer coordinates.
4366    fn lift_buffer_metadata<'a, MBD, M, I>(
4367        &'a self,
4368        query_range: Range<MBD>,
4369        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4370    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4371    where
4372        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4373        MBD: MultiBufferDimension
4374            + Ord
4375            + Sub<Output = MBD::TextDimension>
4376            + ops::Add<MBD::TextDimension, Output = MBD>
4377            + ops::AddAssign<MBD::TextDimension>,
4378        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4379            + ops::Add<Output = MBD::TextDimension>
4380            + AddAssign<MBD::TextDimension>
4381            + Ord,
4382    {
4383        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4384        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4385
4386        // Find the excerpt and buffer offset where the given range ends.
4387        cursor.seek(&query_range.end);
4388        let mut range_end = None;
4389        while let Some(region) = cursor.region() {
4390            if region.is_main_buffer {
4391                let mut buffer_end = region.buffer_range.start;
4392                let overshoot = if query_range.end > region.range.start {
4393                    query_range.end - region.range.start
4394                } else {
4395                    <MBD::TextDimension>::default()
4396                };
4397                buffer_end = buffer_end + overshoot;
4398                range_end = Some((region.excerpt.id, buffer_end));
4399                break;
4400            }
4401            cursor.next();
4402        }
4403
4404        cursor.seek(&query_range.start);
4405
4406        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4407            && region.range.start > MBD::default()
4408        {
4409            cursor.prev()
4410        } else if let Some(region) = cursor.region()
4411            && region.is_main_buffer
4412            && region.diff_hunk_status.is_some()
4413        {
4414            cursor.prev();
4415            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4416                cursor.next();
4417            }
4418        }
4419
4420        iter::from_fn(move || {
4421            loop {
4422                let excerpt = cursor.excerpt()?;
4423
4424                // If we have already retrieved metadata for this excerpt, continue to use it.
4425                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4426                    .as_mut()
4427                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4428                {
4429                    Some(metadata)
4430                }
4431                // Otherwise, compute the intersection of the input range with the excerpt's range,
4432                // and retrieve the metadata for the resulting range.
4433                else {
4434                    let region = cursor.region()?;
4435                    let mut buffer_start;
4436                    if region.is_main_buffer {
4437                        buffer_start = region.buffer_range.start;
4438                        if query_range.start > region.range.start {
4439                            let overshoot = query_range.start - region.range.start;
4440                            buffer_start = buffer_start + overshoot;
4441                        }
4442                        buffer_start = buffer_start.min(region.buffer_range.end);
4443                    } else {
4444                        buffer_start = cursor.main_buffer_position()?;
4445                    };
4446                    let mut buffer_end = excerpt
4447                        .range
4448                        .context
4449                        .end
4450                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4451                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4452                        && excerpt.id == end_excerpt_id
4453                    {
4454                        buffer_end = buffer_end.min(end_buffer_offset);
4455                    }
4456
4457                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4458                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4459                    })
4460                };
4461
4462                // Visit each metadata item.
4463                if let Some((metadata_buffer_range, metadata)) =
4464                    metadata_iter.and_then(Iterator::next)
4465                {
4466                    // Find the multibuffer regions that contain the start and end of
4467                    // the metadata item's range.
4468                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4469                        while let Some(region) = cursor.region() {
4470                            if (region.is_main_buffer
4471                                && (region.buffer_range.end >= metadata_buffer_range.start
4472                                    || cursor.is_at_end_of_excerpt()))
4473                                || (!region.is_main_buffer
4474                                    && region.buffer_range.start == metadata_buffer_range.start)
4475                            {
4476                                break;
4477                            }
4478                            cursor.next();
4479                        }
4480                    }
4481                    let start_region = cursor.region()?.clone();
4482                    while let Some(region) = cursor.region() {
4483                        if region.is_main_buffer
4484                            && (region.buffer_range.end > metadata_buffer_range.end
4485                                || cursor.is_at_end_of_excerpt())
4486                        {
4487                            break;
4488                        }
4489                        cursor.next();
4490                    }
4491                    let end_region = cursor.region();
4492
4493                    // Convert the metadata item's range into multibuffer coordinates.
4494                    let mut start_position = start_region.range.start;
4495                    let region_buffer_start = start_region.buffer_range.start;
4496                    if start_region.is_main_buffer
4497                        && metadata_buffer_range.start > region_buffer_start
4498                    {
4499                        start_position =
4500                            start_position + (metadata_buffer_range.start - region_buffer_start);
4501                        start_position = start_position.min(start_region.range.end);
4502                    }
4503
4504                    let mut end_position = self.max_position();
4505                    if let Some(end_region) = &end_region {
4506                        end_position = end_region.range.start;
4507                        debug_assert!(end_region.is_main_buffer);
4508                        let region_buffer_start = end_region.buffer_range.start;
4509                        if metadata_buffer_range.end > region_buffer_start {
4510                            end_position =
4511                                end_position + (metadata_buffer_range.end - region_buffer_start);
4512                        }
4513                        end_position = end_position.min(end_region.range.end);
4514                    }
4515
4516                    if start_position <= query_range.end && end_position >= query_range.start {
4517                        return Some((start_position..end_position, metadata, excerpt));
4518                    }
4519                }
4520                // When there are no more metadata items for this excerpt, move to the next excerpt.
4521                else {
4522                    current_excerpt_metadata.take();
4523                    if let Some((end_excerpt_id, _)) = range_end
4524                        && excerpt.id == end_excerpt_id
4525                    {
4526                        return None;
4527                    }
4528                    cursor.next_excerpt_forwards();
4529                }
4530            }
4531        })
4532    }
4533
4534    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4535        let offset = position.to_offset(self);
4536
4537        let mut cursor = self
4538            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4539            );
4540        cursor.seek(&DimensionPair {
4541            key: offset,
4542            value: None,
4543        });
4544        cursor.seek_to_start_of_current_excerpt();
4545        let excerpt = cursor.excerpt()?;
4546
4547        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4548        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4549        let current_position = self
4550            .anchor_before(offset)
4551            .text_anchor
4552            .to_offset(&excerpt.buffer);
4553
4554        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4555            if diff.is_inverted {
4556                for hunk in diff.hunks_intersecting_base_text_range_rev(
4557                    excerpt_start..excerpt_end,
4558                    diff.original_buffer_snapshot(),
4559                ) {
4560                    if hunk.diff_base_byte_range.end >= current_position {
4561                        continue;
4562                    }
4563                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4564                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4565                    return Some(MultiBufferRow(start.row));
4566                }
4567            } else {
4568                let excerpt_end = excerpt
4569                    .buffer
4570                    .anchor_before(excerpt_end.min(current_position));
4571                for hunk in diff.hunks_intersecting_range_rev(
4572                    excerpt.range.context.start..excerpt_end,
4573                    &excerpt.buffer,
4574                ) {
4575                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4576                    if hunk_end >= current_position {
4577                        continue;
4578                    }
4579                    let start =
4580                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4581                    return Some(MultiBufferRow(start.row));
4582                }
4583            }
4584        }
4585
4586        loop {
4587            cursor.prev_excerpt();
4588            let excerpt = cursor.excerpt()?;
4589
4590            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4591                continue;
4592            };
4593            if diff.is_inverted {
4594                let Some(hunk) = diff
4595                    .hunks_intersecting_base_text_range_rev(
4596                        excerpt.range.context.to_offset(&excerpt.buffer),
4597                        diff.original_buffer_snapshot(),
4598                    )
4599                    .next()
4600                else {
4601                    continue;
4602                };
4603                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4604                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4605                return Some(MultiBufferRow(start.row));
4606            } else {
4607                let Some(hunk) = diff
4608                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4609                    .next()
4610                else {
4611                    continue;
4612                };
4613                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4614                return Some(MultiBufferRow(start.row));
4615            }
4616        }
4617    }
4618
4619    pub fn has_diff_hunks(&self) -> bool {
4620        self.diffs.values().any(|diff| !diff.is_empty())
4621    }
4622
4623    pub fn is_inside_word<T: ToOffset>(
4624        &self,
4625        position: T,
4626        scope_context: Option<CharScopeContext>,
4627    ) -> bool {
4628        let position = position.to_offset(self);
4629        let classifier = self
4630            .char_classifier_at(position)
4631            .scope_context(scope_context);
4632        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4633        let prev_char_kind = self
4634            .reversed_chars_at(position)
4635            .next()
4636            .map(|c| classifier.kind(c));
4637        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4638    }
4639
4640    pub fn surrounding_word<T: ToOffset>(
4641        &self,
4642        start: T,
4643        scope_context: Option<CharScopeContext>,
4644    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4645        let mut start = start.to_offset(self);
4646        let mut end = start;
4647        let mut next_chars = self.chars_at(start).peekable();
4648        let mut prev_chars = self.reversed_chars_at(start).peekable();
4649
4650        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4651
4652        let word_kind = cmp::max(
4653            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4654            next_chars.peek().copied().map(|c| classifier.kind(c)),
4655        );
4656
4657        for ch in prev_chars {
4658            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4659                start -= ch.len_utf8();
4660            } else {
4661                break;
4662            }
4663        }
4664
4665        for ch in next_chars {
4666            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4667                end += ch.len_utf8();
4668            } else {
4669                break;
4670            }
4671        }
4672
4673        (start..end, word_kind)
4674    }
4675
4676    pub fn char_kind_before<T: ToOffset>(
4677        &self,
4678        start: T,
4679        scope_context: Option<CharScopeContext>,
4680    ) -> Option<CharKind> {
4681        let start = start.to_offset(self);
4682        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4683        self.reversed_chars_at(start)
4684            .next()
4685            .map(|ch| classifier.kind(ch))
4686    }
4687
4688    pub fn is_singleton(&self) -> bool {
4689        self.singleton
4690    }
4691
4692    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4693        if self.singleton {
4694            self.excerpts
4695                .iter()
4696                .next()
4697                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4698        } else {
4699            None
4700        }
4701    }
4702
4703    pub fn len(&self) -> MultiBufferOffset {
4704        self.diff_transforms.summary().output.len
4705    }
4706
4707    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4708        MBD::from_summary(&self.text_summary())
4709    }
4710
4711    pub fn is_empty(&self) -> bool {
4712        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4713    }
4714
4715    pub fn widest_line_number(&self) -> u32 {
4716        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4717        self.excerpts.summary().widest_line_number + 1
4718    }
4719
4720    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4721        let range = range.start.to_offset(self)..range.end.to_offset(self);
4722        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4723        excerpts.seek(&range.start);
4724
4725        let mut chunk;
4726        let mut has_trailing_newline;
4727        let excerpt_bytes;
4728        if let Some(region) = excerpts.region() {
4729            let mut bytes = region.buffer.bytes_in_range(
4730                region.buffer_range.start + (range.start - region.range.start)
4731                    ..(region.buffer_range.start + (range.end - region.range.start))
4732                        .min(region.buffer_range.end),
4733            );
4734            chunk = bytes.next().unwrap_or(&[][..]);
4735            excerpt_bytes = Some(bytes);
4736            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4737            if chunk.is_empty() && has_trailing_newline {
4738                chunk = b"\n";
4739                has_trailing_newline = false;
4740            }
4741        } else {
4742            chunk = &[][..];
4743            excerpt_bytes = None;
4744            has_trailing_newline = false;
4745        };
4746
4747        MultiBufferBytes {
4748            range,
4749            cursor: excerpts,
4750            excerpt_bytes,
4751            has_trailing_newline,
4752            chunk,
4753        }
4754    }
4755
4756    pub fn reversed_bytes_in_range<T: ToOffset>(
4757        &self,
4758        range: Range<T>,
4759    ) -> ReversedMultiBufferBytes<'_> {
4760        let range = range.start.to_offset(self)..range.end.to_offset(self);
4761        let mut chunks = self.reversed_chunks_in_range(range.clone());
4762        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4763        ReversedMultiBufferBytes {
4764            range,
4765            chunks,
4766            chunk,
4767        }
4768    }
4769
4770    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4771        let mut cursor = self.cursor::<Point, Point>();
4772        cursor.seek(&Point::new(start_row.0, 0));
4773        let mut result = MultiBufferRows {
4774            point: Point::new(0, 0),
4775            is_empty: self.excerpts.is_empty(),
4776            is_singleton: self.is_singleton(),
4777            cursor,
4778        };
4779        result.seek(start_row);
4780        result
4781    }
4782
4783    pub fn chunks<T: ToOffset>(
4784        &self,
4785        range: Range<T>,
4786        language_aware: bool,
4787    ) -> MultiBufferChunks<'_> {
4788        let mut chunks = MultiBufferChunks {
4789            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4790                ..ExcerptDimension(MultiBufferOffset::ZERO),
4791            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4792            excerpts: self.excerpts.cursor(()),
4793            diff_transforms: self.diff_transforms.cursor(()),
4794            diffs: &self.diffs,
4795            diff_base_chunks: None,
4796            excerpt_chunks: None,
4797            buffer_chunk: None,
4798            language_aware,
4799        };
4800        let range = range.start.to_offset(self)..range.end.to_offset(self);
4801        chunks.seek(range);
4802        chunks
4803    }
4804
4805    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4806        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4807    }
4808
4809    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4810        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4811    }
4812
4813    pub fn clip_offset_utf16(
4814        &self,
4815        offset: MultiBufferOffsetUtf16,
4816        bias: Bias,
4817    ) -> MultiBufferOffsetUtf16 {
4818        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4819    }
4820
4821    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4822        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4823            buffer.clip_point_utf16(Unclipped(point), bias)
4824        })
4825    }
4826
4827    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4828        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4829    }
4830
4831    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4832        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4833    }
4834
4835    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4836        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4837    }
4838
4839    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4840        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4841    }
4842
4843    #[instrument(skip_all)]
4844    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4845        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4846    }
4847
4848    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4849        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4850    }
4851
4852    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4853        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4854    }
4855
4856    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4857        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4858    }
4859
4860    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4861        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4862    }
4863
4864    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4865        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4866    }
4867
4868    fn clip_dimension<MBD, BD>(
4869        &self,
4870        position: MBD,
4871        bias: Bias,
4872        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4873    ) -> MBD
4874    where
4875        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4876        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4877    {
4878        let mut cursor = self.cursor::<MBD, BD>();
4879        cursor.seek(&position);
4880        if let Some(region) = cursor.region() {
4881            if position >= region.range.end {
4882                return region.range.end;
4883            }
4884            let overshoot = position - region.range.start;
4885            let mut buffer_position = region.buffer_range.start;
4886            buffer_position += overshoot;
4887            let clipped_buffer_position =
4888                clip_buffer_position(region.buffer, buffer_position, bias);
4889            let mut position = region.range.start;
4890            position += clipped_buffer_position - region.buffer_range.start;
4891            position
4892        } else {
4893            self.max_position()
4894        }
4895    }
4896
4897    #[instrument(skip_all)]
4898    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4899        &self,
4900        key: MBR1,
4901        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4902    ) -> MBR2
4903    where
4904        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4905        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4906        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4907        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4908    {
4909        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4910        cursor.seek(&DimensionPair { key, value: None });
4911        if let Some(region) = cursor.region() {
4912            if key >= region.range.end.key {
4913                return region.range.end.value.unwrap();
4914            }
4915            let start_key = region.range.start.key;
4916            let start_value = region.range.start.value.unwrap();
4917            let buffer_start_key = region.buffer_range.start.key;
4918            let buffer_start_value = region.buffer_range.start.value.unwrap();
4919            let mut buffer_key = buffer_start_key;
4920            buffer_key += key - start_key;
4921            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4922            let mut result = start_value;
4923            result += buffer_value - buffer_start_value;
4924            result
4925        } else {
4926            self.max_position()
4927        }
4928    }
4929
4930    pub fn point_to_buffer_offset<T: ToOffset>(
4931        &self,
4932        point: T,
4933    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4934        let offset = point.to_offset(self);
4935        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4936        cursor.seek(&offset);
4937        let region = cursor.region()?;
4938        let overshoot = offset - region.range.start;
4939        let buffer_offset = region.buffer_range.start + overshoot;
4940        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4941            && region.has_trailing_newline
4942            && !region.is_main_buffer
4943        {
4944            let main_buffer_position = cursor.main_buffer_position()?;
4945            let buffer_snapshot = &cursor.excerpt()?.buffer;
4946            return Some((buffer_snapshot, main_buffer_position));
4947        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4948            return None;
4949        }
4950        Some((region.buffer, buffer_offset))
4951    }
4952
4953    pub fn point_to_buffer_point(
4954        &self,
4955        point: Point,
4956    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4957        let mut cursor = self.cursor::<Point, Point>();
4958        cursor.seek(&point);
4959        let region = cursor.region()?;
4960        let overshoot = point - region.range.start;
4961        let buffer_point = region.buffer_range.start + overshoot;
4962        let excerpt = cursor.excerpt()?;
4963        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4964            && region.has_trailing_newline
4965            && !region.is_main_buffer
4966        {
4967            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4968        } else if buffer_point > region.buffer.max_point() {
4969            return None;
4970        }
4971        Some((region.buffer, buffer_point, excerpt.id))
4972    }
4973
4974    pub fn suggested_indents(
4975        &self,
4976        rows: impl IntoIterator<Item = u32>,
4977        cx: &App,
4978    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4979        let mut result = BTreeMap::new();
4980        self.suggested_indents_callback(
4981            rows,
4982            |row, indent| {
4983                result.insert(row, indent);
4984                ControlFlow::Continue(())
4985            },
4986            cx,
4987        );
4988        result
4989    }
4990
4991    // move this to be a generator once those are a thing
4992    pub fn suggested_indents_callback(
4993        &self,
4994        rows: impl IntoIterator<Item = u32>,
4995        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4996        cx: &App,
4997    ) {
4998        let mut rows_for_excerpt = Vec::new();
4999        let mut cursor = self.cursor::<Point, Point>();
5000        let mut rows = rows.into_iter().peekable();
5001        let mut prev_row = u32::MAX;
5002        let mut prev_language_indent_size = IndentSize::default();
5003
5004        while let Some(row) = rows.next() {
5005            cursor.seek(&Point::new(row, 0));
5006            let Some(region) = cursor.region() else {
5007                continue;
5008            };
5009
5010            // Retrieve the language and indent size once for each disjoint region being indented.
5011            let single_indent_size = if row.saturating_sub(1) == prev_row {
5012                prev_language_indent_size
5013            } else {
5014                region
5015                    .buffer
5016                    .language_indent_size_at(Point::new(row, 0), cx)
5017            };
5018            prev_language_indent_size = single_indent_size;
5019            prev_row = row;
5020
5021            let start_buffer_row = region.buffer_range.start.row;
5022            let start_multibuffer_row = region.range.start.row;
5023            let end_multibuffer_row = region.range.end.row;
5024
5025            rows_for_excerpt.push(row);
5026            while let Some(next_row) = rows.peek().copied() {
5027                if end_multibuffer_row > next_row {
5028                    rows_for_excerpt.push(next_row);
5029                    rows.next();
5030                } else {
5031                    break;
5032                }
5033            }
5034
5035            let buffer_rows = rows_for_excerpt
5036                .drain(..)
5037                .map(|row| start_buffer_row + row - start_multibuffer_row);
5038            let buffer_indents = region
5039                .buffer
5040                .suggested_indents(buffer_rows, single_indent_size);
5041            for (row, indent) in buffer_indents {
5042                if cb(
5043                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5044                    indent,
5045                )
5046                .is_break()
5047                {
5048                    return;
5049                }
5050            }
5051        }
5052    }
5053
5054    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5055        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5056            let mut size = buffer.indent_size_for_line(range.start.row);
5057            size.len = size
5058                .len
5059                .min(range.end.column)
5060                .saturating_sub(range.start.column);
5061            size
5062        } else {
5063            IndentSize::spaces(0)
5064        }
5065    }
5066
5067    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5068        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5069            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5070        } else {
5071            LineIndent::spaces(0)
5072        }
5073    }
5074
5075    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5076        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5077
5078        if self.language_settings(cx).extend_comment_on_newline
5079            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5080        {
5081            let delimiters = language_scope.line_comment_prefixes();
5082            for delimiter in delimiters {
5083                if *self
5084                    .chars_at(Point::new(row.0, indent.len() as u32))
5085                    .take(delimiter.chars().count())
5086                    .collect::<String>()
5087                    .as_str()
5088                    == **delimiter
5089                {
5090                    indent.push_str(delimiter);
5091                    break;
5092                }
5093            }
5094        }
5095
5096        indent
5097    }
5098
5099    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5100    where
5101        T: ToOffset,
5102    {
5103        for char in self.reversed_chars_at(position) {
5104            if !char.is_whitespace() {
5105                return false;
5106            }
5107            if char == '\n' {
5108                return true;
5109            }
5110        }
5111        true
5112    }
5113
5114    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5115        while row.0 > 0 {
5116            row.0 -= 1;
5117            if !self.is_line_blank(row) {
5118                return Some(row);
5119            }
5120        }
5121        None
5122    }
5123
5124    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5125        if let Some((_, range)) = self.buffer_line_for_row(row) {
5126            range.end.column - range.start.column
5127        } else {
5128            0
5129        }
5130    }
5131
5132    pub fn buffer_line_for_row(
5133        &self,
5134        row: MultiBufferRow,
5135    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5136        let mut cursor = self.cursor::<Point, Point>();
5137        let point = Point::new(row.0, 0);
5138        cursor.seek(&point);
5139        let region = cursor.region()?;
5140        let overshoot = point.min(region.range.end) - region.range.start;
5141        let buffer_point = region.buffer_range.start + overshoot;
5142        if buffer_point.row > region.buffer_range.end.row {
5143            return None;
5144        }
5145        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5146        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5147            .min(region.buffer_range.end);
5148        Some((region.buffer, line_start..line_end))
5149    }
5150
5151    pub fn max_point(&self) -> Point {
5152        self.text_summary().lines
5153    }
5154
5155    pub fn max_row(&self) -> MultiBufferRow {
5156        MultiBufferRow(self.text_summary().lines.row)
5157    }
5158
5159    pub fn text_summary(&self) -> MBTextSummary {
5160        self.diff_transforms.summary().output
5161    }
5162
5163    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5164    where
5165        MBD: MultiBufferDimension + AddAssign,
5166        O: ToOffset,
5167    {
5168        let range = range.start.to_offset(self)..range.end.to_offset(self);
5169        let mut cursor = self
5170            .diff_transforms
5171            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5172        cursor.seek(&range.start, Bias::Right);
5173
5174        let Some(first_transform) = cursor.item() else {
5175            return MBD::from_summary(&MBTextSummary::default());
5176        };
5177
5178        let diff_transform_start = cursor.start().0;
5179        let diff_transform_end = cursor.end().0;
5180        let diff_start = range.start;
5181        let start_overshoot = diff_start - diff_transform_start;
5182        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5183
5184        let mut result = match first_transform {
5185            DiffTransform::BufferContent { .. } => {
5186                let excerpt_start = cursor.start().1 + start_overshoot;
5187                let excerpt_end = cursor.start().1 + end_overshoot;
5188                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5189            }
5190            DiffTransform::DeletedHunk {
5191                buffer_id,
5192                base_text_byte_range,
5193                has_trailing_newline,
5194                ..
5195            } => {
5196                let buffer_start = base_text_byte_range.start + start_overshoot;
5197                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5198                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5199                    panic!("{:?} is in non-existent deleted hunk", range.start)
5200                };
5201
5202                let include_trailing_newline =
5203                    *has_trailing_newline && range.end >= diff_transform_end;
5204                if include_trailing_newline {
5205                    buffer_end -= 1;
5206                }
5207
5208                let mut summary = base_text
5209                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5210
5211                if include_trailing_newline {
5212                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5213                        &TextSummary::newline(),
5214                    ))
5215                }
5216
5217                let mut result = MBD::default();
5218                result.add_text_dim(&summary);
5219                result
5220            }
5221        };
5222        if range.end < diff_transform_end {
5223            return result;
5224        }
5225
5226        cursor.next();
5227        result.add_mb_text_summary(
5228            &cursor
5229                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5230                .0,
5231        );
5232
5233        let Some(last_transform) = cursor.item() else {
5234            return result;
5235        };
5236
5237        let overshoot = range.end - cursor.start().0;
5238        let suffix = match last_transform {
5239            DiffTransform::BufferContent { .. } => {
5240                let end = cursor.start().1 + overshoot;
5241                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5242            }
5243            DiffTransform::DeletedHunk {
5244                base_text_byte_range,
5245                buffer_id,
5246                has_trailing_newline,
5247                ..
5248            } => {
5249                let buffer_end = base_text_byte_range.start + overshoot;
5250                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5251                    panic!("{:?} is in non-existent deleted hunk", range.end)
5252                };
5253
5254                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5255                    base_text_byte_range.start..buffer_end,
5256                );
5257                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5258                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5259                        &TextSummary::from("\n"),
5260                    ))
5261                }
5262
5263                let mut result = MBD::default();
5264                result.add_text_dim(&suffix);
5265                result
5266            }
5267        };
5268
5269        result += suffix;
5270        result
5271    }
5272
5273    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5274    where
5275        MBD: MultiBufferDimension + AddAssign,
5276    {
5277        let mut summary = MBD::default();
5278        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5279        cursor.seek(&range.start, Bias::Right);
5280        if let Some(excerpt) = cursor.item() {
5281            let mut end_before_newline = cursor.end();
5282            if excerpt.has_trailing_newline {
5283                end_before_newline -= 1;
5284            }
5285
5286            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5287            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5288            let end_in_excerpt =
5289                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5290            summary.add_text_dim(
5291                &excerpt
5292                    .buffer
5293                    .text_summary_for_range::<MBD::TextDimension, _>(
5294                        start_in_excerpt..end_in_excerpt,
5295                    ),
5296            );
5297
5298            if range.end > end_before_newline {
5299                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5300            }
5301
5302            cursor.next();
5303        }
5304
5305        if range.end > *cursor.start() {
5306            summary += cursor
5307                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5308                .0;
5309            if let Some(excerpt) = cursor.item() {
5310                range.end = cmp::max(*cursor.start(), range.end);
5311
5312                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5313                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5314                summary.add_text_dim(
5315                    &excerpt
5316                        .buffer
5317                        .text_summary_for_range::<MBD::TextDimension, _>(
5318                            excerpt_start..end_in_excerpt,
5319                        ),
5320                );
5321            }
5322        }
5323
5324        summary
5325    }
5326
5327    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5328    where
5329        MBD: MultiBufferDimension
5330            + Ord
5331            + Sub<Output = MBD::TextDimension>
5332            + Sub<MBD::TextDimension, Output = MBD>
5333            + AddAssign<MBD::TextDimension>
5334            + Add<MBD::TextDimension, Output = MBD>,
5335        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5336    {
5337        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5338        let locator = self.excerpt_locator_for_id(excerpt_id);
5339        let (start, _, mut item) = self
5340            .excerpts
5341            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5342        let mut start = MBD::from_summary(&start.text);
5343        if item.is_none() && excerpt_id == ExcerptId::max() {
5344            item = self.excerpts.last();
5345            if let Some(last_summary) = self.excerpts.last_summary() {
5346                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5347            }
5348        }
5349
5350        if self.diff_transforms.is_empty() {
5351            let excerpt_start_position = ExcerptDimension(start);
5352            if let Some(excerpt) = item {
5353                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5354                    return excerpt_start_position.0;
5355                }
5356                let excerpt_buffer_start = excerpt
5357                    .range
5358                    .context
5359                    .start
5360                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5361                let excerpt_buffer_end = excerpt
5362                    .range
5363                    .context
5364                    .end
5365                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5366                let buffer_summary = anchor
5367                    .text_anchor
5368                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5369                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5370                let mut position = excerpt_start_position;
5371                if summary > excerpt_buffer_start {
5372                    position += summary - excerpt_buffer_start;
5373                }
5374
5375                position.0
5376            } else {
5377                excerpt_start_position.0
5378            }
5379        } else {
5380            let mut diff_transforms_cursor = self
5381                .diff_transforms
5382                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5383            diff_transforms_cursor.next();
5384
5385            let excerpt_start_position = ExcerptDimension(start);
5386            if let Some(excerpt) = item {
5387                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5388                    return self.resolve_summary_for_anchor(
5389                        &Anchor::min(),
5390                        excerpt_start_position,
5391                        &mut diff_transforms_cursor,
5392                    );
5393                }
5394                let excerpt_buffer_start = excerpt
5395                    .range
5396                    .context
5397                    .start
5398                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5399                let excerpt_buffer_end = excerpt
5400                    .range
5401                    .context
5402                    .end
5403                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5404                let buffer_summary = anchor
5405                    .text_anchor
5406                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5407                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5408                let mut position = excerpt_start_position;
5409                if summary > excerpt_buffer_start {
5410                    position += summary - excerpt_buffer_start;
5411                }
5412
5413                if diff_transforms_cursor.start().0 < position {
5414                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5415                }
5416                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5417            } else {
5418                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5419                self.resolve_summary_for_anchor(
5420                    &Anchor::max(),
5421                    excerpt_start_position,
5422                    &mut diff_transforms_cursor,
5423                )
5424            }
5425        }
5426    }
5427
5428    fn resolve_summary_for_anchor<MBD>(
5429        &self,
5430        anchor: &Anchor,
5431        excerpt_position: ExcerptDimension<MBD>,
5432        diff_transforms: &mut Cursor<
5433            DiffTransform,
5434            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5435        >,
5436    ) -> MBD
5437    where
5438        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5439    {
5440        loop {
5441            let transform_end_position = diff_transforms.end().0;
5442            let at_transform_end =
5443                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5444            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5445                diff_transforms.next();
5446                continue;
5447            }
5448
5449            let mut position = diff_transforms.start().1;
5450            match diff_transforms.item() {
5451                Some(DiffTransform::DeletedHunk {
5452                    buffer_id,
5453                    base_text_byte_range,
5454                    ..
5455                }) => {
5456                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5457                        && let Some(base_text) =
5458                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5459                        && diff_base_anchor.is_valid(&base_text)
5460                    {
5461                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5462                        if base_text_offset >= base_text_byte_range.start
5463                            && base_text_offset <= base_text_byte_range.end
5464                        {
5465                            let position_in_hunk = base_text
5466                                .text_summary_for_range::<MBD::TextDimension, _>(
5467                                    base_text_byte_range.start..base_text_offset,
5468                                );
5469                            position.0.add_text_dim(&position_in_hunk);
5470                        } else if at_transform_end {
5471                            diff_transforms.next();
5472                            continue;
5473                        }
5474                    }
5475                }
5476                _ => {
5477                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5478                        diff_transforms.next();
5479                        continue;
5480                    }
5481                    let overshoot = excerpt_position - diff_transforms.start().0;
5482                    position += overshoot;
5483                }
5484            }
5485
5486            return position.0;
5487        }
5488    }
5489
5490    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5491        let mut cursor = self
5492            .excerpts
5493            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5494        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5495
5496        cursor.seek(&Some(locator), Bias::Left);
5497        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5498            cursor.prev();
5499        }
5500
5501        let mut position = cursor.start().1;
5502        if let Some(excerpt) = cursor.item()
5503            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5504        {
5505            let excerpt_buffer_start = excerpt
5506                .buffer
5507                .offset_for_anchor(&excerpt.range.context.start);
5508            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5509            let buffer_position = cmp::min(
5510                excerpt_buffer_end,
5511                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5512            );
5513            if buffer_position > excerpt_buffer_start {
5514                position += buffer_position - excerpt_buffer_start;
5515            }
5516        }
5517        position
5518    }
5519
5520    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5521        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5522            excerpt_id = *replacement;
5523        }
5524        excerpt_id
5525    }
5526
5527    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5528    where
5529        MBD: MultiBufferDimension
5530            + Ord
5531            + Sub<Output = MBD::TextDimension>
5532            + AddAssign<MBD::TextDimension>,
5533        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5534        I: 'a + IntoIterator<Item = &'a Anchor>,
5535    {
5536        let mut anchors = anchors.into_iter().peekable();
5537        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5538        let mut diff_transforms_cursor = self
5539            .diff_transforms
5540            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5541        diff_transforms_cursor.next();
5542
5543        let mut summaries = Vec::new();
5544        while let Some(anchor) = anchors.peek() {
5545            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5546
5547            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5548                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5549            });
5550
5551            let locator = self.excerpt_locator_for_id(excerpt_id);
5552            cursor.seek_forward(locator, Bias::Left);
5553            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5554                cursor.prev();
5555            }
5556
5557            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5558            if let Some(excerpt) = cursor.item() {
5559                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5560                    let position = self.resolve_summary_for_anchor(
5561                        &Anchor::min(),
5562                        excerpt_start_position,
5563                        &mut diff_transforms_cursor,
5564                    );
5565                    summaries.extend(excerpt_anchors.map(|_| position));
5566                    continue;
5567                }
5568                let excerpt_buffer_start = excerpt
5569                    .range
5570                    .context
5571                    .start
5572                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5573                let excerpt_buffer_end = excerpt
5574                    .range
5575                    .context
5576                    .end
5577                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5578                for (buffer_summary, anchor) in excerpt
5579                    .buffer
5580                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5581                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5582                    )
5583                {
5584                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5585                    let mut position = excerpt_start_position;
5586                    if summary > excerpt_buffer_start {
5587                        position += summary - excerpt_buffer_start;
5588                    }
5589
5590                    if diff_transforms_cursor.start().0 < position {
5591                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5592                    }
5593
5594                    summaries.push(self.resolve_summary_for_anchor(
5595                        anchor,
5596                        position,
5597                        &mut diff_transforms_cursor,
5598                    ));
5599                }
5600            } else {
5601                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5602                let position = self.resolve_summary_for_anchor(
5603                    &Anchor::max(),
5604                    excerpt_start_position,
5605                    &mut diff_transforms_cursor,
5606                );
5607                summaries.extend(excerpt_anchors.map(|_| position));
5608            }
5609        }
5610
5611        summaries
5612    }
5613
5614    pub fn dimensions_from_points<'a, MBD>(
5615        &'a self,
5616        points: impl 'a + IntoIterator<Item = Point>,
5617    ) -> impl 'a + Iterator<Item = MBD>
5618    where
5619        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5620    {
5621        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5622        cursor.seek(&DimensionPair {
5623            key: Point::default(),
5624            value: None,
5625        });
5626        let mut points = points.into_iter();
5627        iter::from_fn(move || {
5628            let point = points.next()?;
5629
5630            cursor.seek_forward(&DimensionPair {
5631                key: point,
5632                value: None,
5633            });
5634
5635            if let Some(region) = cursor.region() {
5636                let overshoot = point - region.range.start.key;
5637                let buffer_point = region.buffer_range.start + overshoot;
5638                let mut position = region.range.start.value.unwrap();
5639                position.add_text_dim(
5640                    &region
5641                        .buffer
5642                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5643                );
5644                if point == region.range.end.key && region.has_trailing_newline {
5645                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5646                }
5647                Some(position)
5648            } else {
5649                Some(MBD::from_summary(&self.text_summary()))
5650            }
5651        })
5652    }
5653
5654    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5655    where
5656        I: 'a + IntoIterator<Item = &'a Anchor>,
5657    {
5658        let mut anchors = anchors.into_iter().enumerate().peekable();
5659        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5660        cursor.next();
5661
5662        let mut result = Vec::new();
5663
5664        while let Some((_, anchor)) = anchors.peek() {
5665            let old_excerpt_id = anchor.excerpt_id;
5666
5667            // Find the location where this anchor's excerpt should be.
5668            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5669            cursor.seek_forward(&Some(old_locator), Bias::Left);
5670
5671            let next_excerpt = cursor.item();
5672            let prev_excerpt = cursor.prev_item();
5673
5674            // Process all of the anchors for this excerpt.
5675            while let Some((anchor_ix, &anchor)) =
5676                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5677            {
5678                let mut anchor = anchor;
5679
5680                // Leave min and max anchors unchanged if invalid or
5681                // if the old excerpt still exists at this location
5682                let mut kept_position = next_excerpt
5683                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5684                    || old_excerpt_id == ExcerptId::max()
5685                    || old_excerpt_id == ExcerptId::min();
5686
5687                // If the old excerpt no longer exists at this location, then attempt to
5688                // find an equivalent position for this anchor in an adjacent excerpt.
5689                if !kept_position {
5690                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5691                        if excerpt.contains(&anchor) {
5692                            anchor.excerpt_id = excerpt.id;
5693                            kept_position = true;
5694                            break;
5695                        }
5696                    }
5697                }
5698
5699                // If there's no adjacent excerpt that contains the anchor's position,
5700                // then report that the anchor has lost its position.
5701                if !kept_position {
5702                    anchor = if let Some(excerpt) = next_excerpt {
5703                        let mut text_anchor = excerpt
5704                            .range
5705                            .context
5706                            .start
5707                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5708                        if text_anchor
5709                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5710                            .is_gt()
5711                        {
5712                            text_anchor = excerpt.range.context.end;
5713                        }
5714                        Anchor::in_buffer(excerpt.id, text_anchor)
5715                    } else if let Some(excerpt) = prev_excerpt {
5716                        let mut text_anchor = excerpt
5717                            .range
5718                            .context
5719                            .end
5720                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5721                        if text_anchor
5722                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5723                            .is_lt()
5724                        {
5725                            text_anchor = excerpt.range.context.start;
5726                        }
5727                        Anchor::in_buffer(excerpt.id, text_anchor)
5728                    } else if anchor.text_anchor.bias == Bias::Left {
5729                        Anchor::min()
5730                    } else {
5731                        Anchor::max()
5732                    };
5733                }
5734
5735                result.push((anchor_ix, anchor, kept_position));
5736            }
5737        }
5738        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5739        result
5740    }
5741
5742    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5743        self.anchor_at(position, Bias::Left)
5744    }
5745
5746    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5747        self.anchor_at(position, Bias::Right)
5748    }
5749
5750    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5751        let offset = position.to_offset(self);
5752
5753        // Find the given position in the diff transforms. Determine the corresponding
5754        // offset in the excerpts, and whether the position is within a deleted hunk.
5755        let mut diff_transforms = self
5756            .diff_transforms
5757            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5758        diff_transforms.seek(&offset, Bias::Right);
5759
5760        if offset == diff_transforms.start().0
5761            && bias == Bias::Left
5762            && let Some(prev_item) = diff_transforms.prev_item()
5763            && let DiffTransform::DeletedHunk { .. } = prev_item
5764        {
5765            diff_transforms.prev();
5766        }
5767        let offset_in_transform = offset - diff_transforms.start().0;
5768        let mut excerpt_offset = diff_transforms.start().1;
5769        let mut diff_base_anchor = None;
5770        if let Some(DiffTransform::DeletedHunk {
5771            buffer_id,
5772            base_text_byte_range,
5773            has_trailing_newline,
5774            ..
5775        }) = diff_transforms.item()
5776        {
5777            let diff = self.diffs.get(buffer_id).expect("missing diff");
5778            if offset_in_transform > base_text_byte_range.len() {
5779                debug_assert!(*has_trailing_newline);
5780                bias = Bias::Right;
5781            } else {
5782                diff_base_anchor = Some(
5783                    diff.base_text()
5784                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5785                );
5786                bias = Bias::Left;
5787            }
5788        } else {
5789            excerpt_offset += MultiBufferOffset(offset_in_transform);
5790        };
5791
5792        let mut excerpts = self
5793            .excerpts
5794            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5795        excerpts.seek(&excerpt_offset, Bias::Right);
5796        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5797            excerpts.prev();
5798        }
5799        if let Some(excerpt) = excerpts.item() {
5800            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5801            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5802                overshoot -= 1;
5803                bias = Bias::Right;
5804            }
5805
5806            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5807            let text_anchor =
5808                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5809            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5810            match diff_base_anchor {
5811                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5812                None => anchor,
5813            }
5814        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5815        {
5816            Anchor::min()
5817        } else {
5818            Anchor::max()
5819        }
5820    }
5821
5822    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5823    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5824        let (excerpt, buffer, _) = self.as_singleton()?;
5825        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5826            Some(Anchor::in_buffer(*excerpt, text_anchor))
5827        } else {
5828            None
5829        }
5830    }
5831
5832    /// Returns an anchor for the given excerpt and text anchor,
5833    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5834    pub fn anchor_range_in_excerpt(
5835        &self,
5836        excerpt_id: ExcerptId,
5837        text_anchor: Range<text::Anchor>,
5838    ) -> Option<Range<Anchor>> {
5839        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5840
5841        Some(
5842            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5843                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5844        )
5845    }
5846
5847    /// Returns an anchor for the given excerpt and text anchor,
5848    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5849    pub fn anchor_in_excerpt(
5850        &self,
5851        excerpt_id: ExcerptId,
5852        text_anchor: text::Anchor,
5853    ) -> Option<Anchor> {
5854        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5855        Self::anchor_in_excerpt_(excerpt, text_anchor)
5856    }
5857
5858    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5859    pub fn anchors_in_excerpt(
5860        &self,
5861        excerpt_id: ExcerptId,
5862        text_anchors: impl IntoIterator<Item = text::Anchor>,
5863    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5864        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5865        Some(
5866            text_anchors
5867                .into_iter()
5868                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5869        )
5870    }
5871
5872    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5873        match text_anchor.buffer_id {
5874            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5875            Some(_) => return None,
5876            None if text_anchor.is_max() || text_anchor.is_min() => {
5877                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5878            }
5879            None => return None,
5880        }
5881
5882        let context = &excerpt.range.context;
5883        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5884            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5885        {
5886            return None;
5887        }
5888
5889        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5890    }
5891
5892    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5893        Some(self.excerpt(excerpt_id)?.range.context.clone())
5894    }
5895
5896    pub fn excerpt_range_for_excerpt(
5897        &self,
5898        excerpt_id: ExcerptId,
5899    ) -> Option<ExcerptRange<text::Anchor>> {
5900        Some(self.excerpt(excerpt_id)?.range.clone())
5901    }
5902
5903    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5904        if anchor.is_min() || anchor.is_max() {
5905            // todo(lw): should be `!self.is_empty()`
5906            true
5907        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5908            excerpt.buffer.can_resolve(&anchor.text_anchor)
5909        } else {
5910            false
5911        }
5912    }
5913
5914    pub fn excerpts(
5915        &self,
5916    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5917        self.excerpts
5918            .iter()
5919            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5920    }
5921
5922    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5923    where
5924        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5925        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5926    {
5927        let excerpts = self.excerpts.cursor(());
5928        let diff_transforms = self.diff_transforms.cursor(());
5929        MultiBufferCursor {
5930            excerpts,
5931            diff_transforms,
5932            diffs: &self.diffs,
5933            cached_region: OnceCell::new(),
5934        }
5935    }
5936
5937    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5938        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5939        let mut excerpts = self
5940            .excerpts
5941            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5942        excerpts.seek(&Some(start_locator), Bias::Left);
5943        excerpts.prev();
5944
5945        let mut diff_transforms = self
5946            .diff_transforms
5947            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5948        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5949        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5950            diff_transforms.next();
5951        }
5952
5953        let excerpt = excerpts.item()?;
5954        Some(MultiBufferExcerpt {
5955            excerpt,
5956            offset: diff_transforms.start().output_dimension.0,
5957            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5958            excerpt_offset: excerpts.start().1,
5959            diff_transforms,
5960        })
5961    }
5962
5963    pub fn excerpt_boundaries_in_range<R, T>(
5964        &self,
5965        range: R,
5966    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5967    where
5968        R: RangeBounds<T>,
5969        T: ToOffset,
5970    {
5971        let start_offset;
5972        let start = match range.start_bound() {
5973            Bound::Included(start) => {
5974                start_offset = start.to_offset(self);
5975                Bound::Included(start_offset)
5976            }
5977            Bound::Excluded(_) => {
5978                panic!("not supported")
5979            }
5980            Bound::Unbounded => {
5981                start_offset = MultiBufferOffset::ZERO;
5982                Bound::Unbounded
5983            }
5984        };
5985        let end = match range.end_bound() {
5986            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5987            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5988            Bound::Unbounded => Bound::Unbounded,
5989        };
5990        let bounds = (start, end);
5991        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5992        cursor.seek(&DimensionPair {
5993            key: start_offset,
5994            value: None,
5995        });
5996
5997        if cursor
5998            .fetch_excerpt_with_range()
5999            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6000        {
6001            cursor.prev_excerpt();
6002        } else {
6003            cursor.seek_to_start_of_current_excerpt();
6004        }
6005        let mut prev_region = cursor
6006            .fetch_excerpt_with_range()
6007            .map(|(excerpt, _)| excerpt);
6008
6009        cursor.next_excerpt_forwards();
6010
6011        iter::from_fn(move || {
6012            loop {
6013                if self.singleton {
6014                    return None;
6015                }
6016
6017                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6018                cursor.next_excerpt_forwards();
6019                if !bounds.contains(&next_range.start.key) {
6020                    prev_region = Some(next_excerpt);
6021                    continue;
6022                }
6023
6024                let next_region_start = next_range.start.value.unwrap();
6025                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6026                    range.start.value.unwrap()
6027                } else {
6028                    self.max_point()
6029                };
6030
6031                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6032                    id: region.id,
6033                    buffer: region.buffer.clone(),
6034                    buffer_id: region.buffer_id,
6035                    range: region.range.clone(),
6036                    end_row: MultiBufferRow(next_region_start.row),
6037                });
6038
6039                let next = ExcerptInfo {
6040                    id: next_excerpt.id,
6041                    buffer: next_excerpt.buffer.clone(),
6042                    buffer_id: next_excerpt.buffer_id,
6043                    range: next_excerpt.range.clone(),
6044                    end_row: if next_excerpt.has_trailing_newline {
6045                        MultiBufferRow(next_region_end.row - 1)
6046                    } else {
6047                        MultiBufferRow(next_region_end.row)
6048                    },
6049                };
6050
6051                let row = MultiBufferRow(next_region_start.row);
6052
6053                prev_region = Some(next_excerpt);
6054
6055                return Some(ExcerptBoundary { row, prev, next });
6056            }
6057        })
6058    }
6059
6060    pub fn edit_count(&self) -> usize {
6061        self.edit_count
6062    }
6063
6064    pub fn non_text_state_update_count(&self) -> usize {
6065        self.non_text_state_update_count
6066    }
6067
6068    /// Returns the smallest enclosing bracket ranges containing the given range or
6069    /// None if no brackets contain range or the range is not contained in a single
6070    /// excerpt
6071    ///
6072    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6073    #[ztracing::instrument(skip_all)]
6074    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6075        &self,
6076        range: Range<T>,
6077        range_filter: Option<
6078            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6079        >,
6080    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6081        let range = range.start.to_offset(self)..range.end.to_offset(self);
6082        let mut excerpt = self.excerpt_containing(range.clone())?;
6083        let buffer = excerpt.buffer();
6084        let excerpt_buffer_range = excerpt.buffer_range();
6085
6086        // Filter to ranges contained in the excerpt
6087        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6088            excerpt_buffer_range.contains(&BufferOffset(open.start))
6089                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6090                && range_filter.is_none_or(|filter| {
6091                    filter(
6092                        buffer,
6093                        BufferOffset(open.start)..BufferOffset(close.end),
6094                        BufferOffset(close.start)..BufferOffset(close.end),
6095                    )
6096                })
6097        };
6098
6099        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6100            excerpt.map_range_to_buffer(range),
6101            Some(&range_filter),
6102        )?;
6103
6104        Some((
6105            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6106            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6107        ))
6108    }
6109
6110    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6111    /// not contained in a single excerpt
6112    pub fn enclosing_bracket_ranges<T: ToOffset>(
6113        &self,
6114        range: Range<T>,
6115    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6116    {
6117        let range = range.start.to_offset(self)..range.end.to_offset(self);
6118        let mut excerpt = self.excerpt_containing(range.clone())?;
6119
6120        Some(
6121            excerpt
6122                .buffer()
6123                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6124                .filter_map(move |pair| {
6125                    let open_range =
6126                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6127                    let close_range =
6128                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6129                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6130                        Some((
6131                            excerpt.map_range_from_buffer(open_range),
6132                            excerpt.map_range_from_buffer(close_range),
6133                        ))
6134                    } else {
6135                        None
6136                    }
6137                }),
6138        )
6139    }
6140
6141    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6142    /// not contained in a single excerpt
6143    pub fn text_object_ranges<T: ToOffset>(
6144        &self,
6145        range: Range<T>,
6146        options: TreeSitterOptions,
6147    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6148        let range = range.start.to_offset(self)..range.end.to_offset(self);
6149        self.excerpt_containing(range.clone())
6150            .map(|mut excerpt| {
6151                excerpt
6152                    .buffer()
6153                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6154                    .filter_map(move |(range, text_object)| {
6155                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6156                        if excerpt.contains_buffer_range(range.clone()) {
6157                            Some((excerpt.map_range_from_buffer(range), text_object))
6158                        } else {
6159                            None
6160                        }
6161                    })
6162            })
6163            .into_iter()
6164            .flatten()
6165    }
6166
6167    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6168    /// not contained in a single excerpt
6169    pub fn bracket_ranges<T: ToOffset>(
6170        &self,
6171        range: Range<T>,
6172    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6173    {
6174        let range = range.start.to_offset(self)..range.end.to_offset(self);
6175        let mut excerpt = self.excerpt_containing(range.clone())?;
6176        Some(
6177            excerpt
6178                .buffer()
6179                .bracket_ranges(excerpt.map_range_to_buffer(range))
6180                .filter_map(move |pair| {
6181                    let open_range =
6182                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6183                    let close_range =
6184                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6185                    excerpt
6186                        .contains_buffer_range(open_range.start..close_range.end)
6187                        .then(|| BracketMatch {
6188                            open_range: excerpt.map_range_from_buffer(open_range),
6189                            close_range: excerpt.map_range_from_buffer(close_range),
6190                            color_index: pair.color_index,
6191                            newline_only: pair.newline_only,
6192                            syntax_layer_depth: pair.syntax_layer_depth,
6193                        })
6194                })
6195                .map(BracketMatch::bracket_ranges),
6196        )
6197    }
6198
6199    pub fn redacted_ranges<'a, T: ToOffset>(
6200        &'a self,
6201        range: Range<T>,
6202        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6203    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6204        let range = range.start.to_offset(self)..range.end.to_offset(self);
6205        self.lift_buffer_metadata(range, move |buffer, range| {
6206            if redaction_enabled(buffer.file()) {
6207                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6208            } else {
6209                None
6210            }
6211        })
6212        .map(|(range, _, _)| range)
6213    }
6214
6215    pub fn runnable_ranges(
6216        &self,
6217        range: Range<Anchor>,
6218    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6219        let range = range.start.to_offset(self)..range.end.to_offset(self);
6220        self.lift_buffer_metadata(range, move |buffer, range| {
6221            Some(
6222                buffer
6223                    .runnable_ranges(range.clone())
6224                    .filter(move |runnable| {
6225                        runnable.run_range.start >= range.start
6226                            && runnable.run_range.end < range.end
6227                    })
6228                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6229            )
6230        })
6231        .map(|(run_range, runnable, _)| (run_range, runnable))
6232    }
6233
6234    pub fn line_indents(
6235        &self,
6236        start_row: MultiBufferRow,
6237        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6238    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6239        let max_point = self.max_point();
6240        let mut cursor = self.cursor::<Point, Point>();
6241        cursor.seek(&Point::new(start_row.0, 0));
6242        iter::from_fn(move || {
6243            let mut region = cursor.region()?;
6244            while !buffer_filter(&region.excerpt.buffer) {
6245                cursor.next();
6246                region = cursor.region()?;
6247            }
6248            let region = cursor.region()?;
6249            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6250            let buffer_start_row =
6251                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6252
6253            let buffer_end_row = if region.is_main_buffer
6254                && (region.has_trailing_newline || region.range.end == max_point)
6255            {
6256                region.buffer_range.end.row
6257            } else {
6258                region.buffer_range.end.row.saturating_sub(1)
6259            };
6260
6261            let line_indents = region
6262                .buffer
6263                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6264            let region_buffer_row = region.buffer_range.start.row;
6265            let region_row = region.range.start.row;
6266            let region_buffer = &region.excerpt.buffer;
6267            cursor.next();
6268            Some(line_indents.map(move |(buffer_row, indent)| {
6269                let row = region_row + (buffer_row - region_buffer_row);
6270                (MultiBufferRow(row), indent, region_buffer.as_ref())
6271            }))
6272        })
6273        .flatten()
6274    }
6275
6276    pub fn reversed_line_indents(
6277        &self,
6278        end_row: MultiBufferRow,
6279        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6280    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6281        let max_point = self.max_point();
6282        let mut cursor = self.cursor::<Point, Point>();
6283        cursor.seek(&Point::new(end_row.0, 0));
6284        iter::from_fn(move || {
6285            let mut region = cursor.region()?;
6286            while !buffer_filter(&region.excerpt.buffer) {
6287                cursor.prev();
6288                region = cursor.region()?;
6289            }
6290            let region = cursor.region()?;
6291
6292            let buffer_start_row = region.buffer_range.start.row;
6293            let buffer_end_row = if region.is_main_buffer
6294                && (region.has_trailing_newline || region.range.end == max_point)
6295            {
6296                region.buffer_range.end.row + 1
6297            } else {
6298                region.buffer_range.end.row
6299            };
6300
6301            let overshoot = end_row.0 - region.range.start.row;
6302            let buffer_end_row =
6303                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6304
6305            let line_indents = region
6306                .buffer
6307                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6308            let region_buffer_row = region.buffer_range.start.row;
6309            let region_row = region.range.start.row;
6310            let region_buffer = &region.excerpt.buffer;
6311            cursor.prev();
6312            Some(line_indents.map(move |(buffer_row, indent)| {
6313                let row = region_row + (buffer_row - region_buffer_row);
6314                (MultiBufferRow(row), indent, region_buffer.as_ref())
6315            }))
6316        })
6317        .flatten()
6318    }
6319
6320    pub async fn enclosing_indent(
6321        &self,
6322        mut target_row: MultiBufferRow,
6323    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6324        let max_row = MultiBufferRow(self.max_point().row);
6325        if target_row >= max_row {
6326            return None;
6327        }
6328
6329        let mut target_indent = self.line_indent_for_row(target_row);
6330
6331        // If the current row is at the start of an indented block, we want to return this
6332        // block as the enclosing indent.
6333        if !target_indent.is_line_empty() && target_row < max_row {
6334            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6335            if !next_line_indent.is_line_empty()
6336                && target_indent.raw_len() < next_line_indent.raw_len()
6337            {
6338                target_indent = next_line_indent;
6339                target_row.0 += 1;
6340            }
6341        }
6342
6343        const SEARCH_ROW_LIMIT: u32 = 25000;
6344        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6345        const YIELD_INTERVAL: u32 = 100;
6346
6347        let mut accessed_row_counter = 0;
6348
6349        // If there is a blank line at the current row, search for the next non indented lines
6350        if target_indent.is_line_empty() {
6351            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6352            let end =
6353                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6354
6355            let mut non_empty_line_above = None;
6356            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6357                if row < start {
6358                    break;
6359                }
6360                accessed_row_counter += 1;
6361                if accessed_row_counter == YIELD_INTERVAL {
6362                    accessed_row_counter = 0;
6363                    yield_now().await;
6364                }
6365                if !indent.is_line_empty() {
6366                    non_empty_line_above = Some((row, indent));
6367                    break;
6368                }
6369            }
6370
6371            let mut non_empty_line_below = None;
6372            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6373                if row > end {
6374                    break;
6375                }
6376                accessed_row_counter += 1;
6377                if accessed_row_counter == YIELD_INTERVAL {
6378                    accessed_row_counter = 0;
6379                    yield_now().await;
6380                }
6381                if !indent.is_line_empty() {
6382                    non_empty_line_below = Some((row, indent));
6383                    break;
6384                }
6385            }
6386
6387            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6388                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6389                    if above_indent.raw_len() >= below_indent.raw_len() {
6390                        (above_row, above_indent)
6391                    } else {
6392                        (below_row, below_indent)
6393                    }
6394                }
6395                (Some(above), None) => above,
6396                (None, Some(below)) => below,
6397                _ => return None,
6398            };
6399
6400            target_indent = indent;
6401            target_row = row;
6402        }
6403
6404        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6405        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6406
6407        let mut start_indent = None;
6408        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6409            if row < start {
6410                break;
6411            }
6412            accessed_row_counter += 1;
6413            if accessed_row_counter == YIELD_INTERVAL {
6414                accessed_row_counter = 0;
6415                yield_now().await;
6416            }
6417            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6418                start_indent = Some((row, indent));
6419                break;
6420            }
6421        }
6422        let (start_row, start_indent_size) = start_indent?;
6423
6424        let mut end_indent = (end, None);
6425        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6426            if row > end {
6427                break;
6428            }
6429            accessed_row_counter += 1;
6430            if accessed_row_counter == YIELD_INTERVAL {
6431                accessed_row_counter = 0;
6432                yield_now().await;
6433            }
6434            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6435                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6436                break;
6437            }
6438        }
6439        let (end_row, end_indent_size) = end_indent;
6440
6441        let indent = if let Some(end_indent_size) = end_indent_size {
6442            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6443                start_indent_size
6444            } else {
6445                end_indent_size
6446            }
6447        } else {
6448            start_indent_size
6449        };
6450
6451        Some((start_row..end_row, indent))
6452    }
6453
6454    pub fn indent_guides_in_range<T: ToPoint>(
6455        &self,
6456        range: Range<T>,
6457        ignore_disabled_for_language: bool,
6458        cx: &App,
6459    ) -> impl Iterator<Item = IndentGuide> {
6460        let range = range.start.to_point(self)..range.end.to_point(self);
6461        let start_row = MultiBufferRow(range.start.row);
6462        let end_row = MultiBufferRow(range.end.row);
6463
6464        let mut row_indents = self.line_indents(start_row, |buffer| {
6465            let settings =
6466                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6467            settings.indent_guides.enabled || ignore_disabled_for_language
6468        });
6469
6470        let mut result = Vec::new();
6471        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6472
6473        let mut prev_settings = None;
6474        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6475            if first_row > end_row {
6476                break;
6477            }
6478            let current_depth = indent_stack.len() as u32;
6479
6480            // Avoid retrieving the language settings repeatedly for every buffer row.
6481            if let Some((prev_buffer_id, _)) = &prev_settings
6482                && prev_buffer_id != &buffer.remote_id()
6483            {
6484                prev_settings.take();
6485            }
6486            let settings = &prev_settings
6487                .get_or_insert_with(|| {
6488                    (
6489                        buffer.remote_id(),
6490                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6491                    )
6492                })
6493                .1;
6494            let tab_size = settings.tab_size.get();
6495
6496            // When encountering empty, continue until found useful line indent
6497            // then add to the indent stack with the depth found
6498            let mut found_indent = false;
6499            let mut last_row = first_row;
6500            if line_indent.is_line_blank() {
6501                while !found_indent {
6502                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6503                        break;
6504                    };
6505                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6506                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6507                        break;
6508                    }
6509
6510                    if new_line_indent.is_line_blank() {
6511                        continue;
6512                    }
6513                    last_row = target_row.min(end_row);
6514                    line_indent = new_line_indent;
6515                    found_indent = true;
6516                    break;
6517                }
6518            } else {
6519                found_indent = true
6520            }
6521
6522            let depth = if found_indent {
6523                line_indent.len(tab_size) / tab_size
6524            } else {
6525                0
6526            };
6527
6528            match depth.cmp(&current_depth) {
6529                cmp::Ordering::Less => {
6530                    for _ in 0..(current_depth - depth) {
6531                        let mut indent = indent_stack.pop().unwrap();
6532                        if last_row != first_row {
6533                            // In this case, we landed on an empty row, had to seek forward,
6534                            // and discovered that the indent we where on is ending.
6535                            // This means that the last display row must
6536                            // be on line that ends this indent range, so we
6537                            // should display the range up to the first non-empty line
6538                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6539                        }
6540
6541                        result.push(indent)
6542                    }
6543                }
6544                cmp::Ordering::Greater => {
6545                    for next_depth in current_depth..depth {
6546                        indent_stack.push(IndentGuide {
6547                            buffer_id: buffer.remote_id(),
6548                            start_row: first_row,
6549                            end_row: last_row,
6550                            depth: next_depth,
6551                            tab_size,
6552                            settings: settings.indent_guides.clone(),
6553                        });
6554                    }
6555                }
6556                _ => {}
6557            }
6558
6559            for indent in indent_stack.iter_mut() {
6560                indent.end_row = last_row;
6561            }
6562        }
6563
6564        result.extend(indent_stack);
6565        result.into_iter()
6566    }
6567
6568    pub fn trailing_excerpt_update_count(&self) -> usize {
6569        self.trailing_excerpt_update_count
6570    }
6571
6572    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6573        self.point_to_buffer_offset(point)
6574            .and_then(|(buffer, _)| buffer.file())
6575    }
6576
6577    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6578        self.point_to_buffer_offset(offset)
6579            .and_then(|(buffer, offset)| buffer.language_at(offset))
6580    }
6581
6582    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6583        self.excerpts
6584            .first()
6585            .map(|excerpt| &excerpt.buffer)
6586            .map(|buffer| {
6587                language_settings(
6588                    buffer.language().map(|language| language.name()),
6589                    buffer.file(),
6590                    cx,
6591                )
6592            })
6593            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6594    }
6595
6596    pub fn language_settings_at<'a, T: ToOffset>(
6597        &'a self,
6598        point: T,
6599        cx: &'a App,
6600    ) -> Cow<'a, LanguageSettings> {
6601        let mut language = None;
6602        let mut file = None;
6603        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6604            language = buffer.language_at(offset);
6605            file = buffer.file();
6606        }
6607        language_settings(language.map(|l| l.name()), file, cx)
6608    }
6609
6610    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6611        self.point_to_buffer_offset(point)
6612            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6613    }
6614
6615    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6616        self.point_to_buffer_offset(point)
6617            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6618            .unwrap_or_default()
6619    }
6620
6621    pub fn language_indent_size_at<T: ToOffset>(
6622        &self,
6623        position: T,
6624        cx: &App,
6625    ) -> Option<IndentSize> {
6626        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6627        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6628    }
6629
6630    pub fn is_dirty(&self) -> bool {
6631        self.is_dirty
6632    }
6633
6634    pub fn has_deleted_file(&self) -> bool {
6635        self.has_deleted_file
6636    }
6637
6638    pub fn has_conflict(&self) -> bool {
6639        self.has_conflict
6640    }
6641
6642    pub fn has_diagnostics(&self) -> bool {
6643        self.excerpts
6644            .iter()
6645            .any(|excerpt| excerpt.buffer.has_diagnostics())
6646    }
6647
6648    pub fn diagnostic_group(
6649        &self,
6650        buffer_id: BufferId,
6651        group_id: usize,
6652    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6653        self.lift_buffer_metadata::<Point, _, _>(
6654            Point::zero()..self.max_point(),
6655            move |buffer, range| {
6656                if buffer.remote_id() != buffer_id {
6657                    return None;
6658                };
6659                Some(
6660                    buffer
6661                        .diagnostics_in_range(range, false)
6662                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6663                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6664                )
6665            },
6666        )
6667        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6668    }
6669
6670    pub fn diagnostics_in_range<'a, MBD>(
6671        &'a self,
6672        range: Range<MBD>,
6673    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6674    where
6675        MBD::TextDimension: 'a
6676            + text::ToOffset
6677            + text::FromAnchor
6678            + Sub<Output = MBD::TextDimension>
6679            + fmt::Debug
6680            + ops::Add<Output = MBD::TextDimension>
6681            + ops::AddAssign
6682            + Ord,
6683        MBD: MultiBufferDimension
6684            + Ord
6685            + Sub<Output = MBD::TextDimension>
6686            + ops::Add<MBD::TextDimension, Output = MBD>
6687            + ops::AddAssign<MBD::TextDimension>
6688            + 'a,
6689    {
6690        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6691            Some(
6692                buffer
6693                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6694                    .map(|entry| (entry.range, entry.diagnostic)),
6695            )
6696        })
6697        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6698    }
6699
6700    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6701        &'a self,
6702        range: Range<MBD>,
6703    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6704    where
6705        MBD: MultiBufferDimension
6706            + Ord
6707            + Sub<Output = MBD::TextDimension>
6708            + ops::Add<MBD::TextDimension, Output = MBD>
6709            + ops::AddAssign<MBD::TextDimension>,
6710        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6711            + ops::Add<Output = MBD::TextDimension>
6712            + text::ToOffset
6713            + text::FromAnchor
6714            + AddAssign<MBD::TextDimension>
6715            + Ord,
6716    {
6717        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6718            Some(
6719                buffer
6720                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6721                    .map(|entry| (entry.range, entry.diagnostic)),
6722            )
6723        })
6724        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6725    }
6726
6727    pub fn syntax_ancestor<T: ToOffset>(
6728        &self,
6729        range: Range<T>,
6730    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6731        let range = range.start.to_offset(self)..range.end.to_offset(self);
6732        let mut excerpt = self.excerpt_containing(range.clone())?;
6733        let node = excerpt
6734            .buffer()
6735            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6736        let node_range = node.byte_range();
6737        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6738        if !excerpt.contains_buffer_range(node_range.clone()) {
6739            return None;
6740        };
6741        Some((node, excerpt.map_range_from_buffer(node_range)))
6742    }
6743
6744    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6745        let (excerpt_id, _, buffer) = self.as_singleton()?;
6746        let outline = buffer.outline(theme);
6747        Some(Outline::new(
6748            outline
6749                .items
6750                .into_iter()
6751                .flat_map(|item| {
6752                    Some(OutlineItem {
6753                        depth: item.depth,
6754                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6755                        source_range_for_text: self
6756                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6757                        text: item.text,
6758                        highlight_ranges: item.highlight_ranges,
6759                        name_ranges: item.name_ranges,
6760                        body_range: item.body_range.and_then(|body_range| {
6761                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6762                        }),
6763                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6764                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6765                        }),
6766                    })
6767                })
6768                .collect(),
6769        ))
6770    }
6771
6772    pub fn symbols_containing<T: ToOffset>(
6773        &self,
6774        offset: T,
6775        theme: Option<&SyntaxTheme>,
6776    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6777        let anchor = self.anchor_before(offset);
6778        let excerpt @ &Excerpt {
6779            id: excerpt_id,
6780            buffer_id,
6781            ref buffer,
6782            ..
6783        } = self.excerpt(anchor.excerpt_id)?;
6784        if cfg!(debug_assertions) {
6785            match anchor.text_anchor.buffer_id {
6786                // we clearly are hitting this according to sentry, but in what situations can this occur?
6787                Some(anchor_buffer_id) => {
6788                    assert_eq!(
6789                        anchor_buffer_id, buffer_id,
6790                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6791                    )
6792                }
6793                None => assert!(anchor.is_max()),
6794            }
6795        };
6796        Some((
6797            buffer_id,
6798            buffer
6799                .symbols_containing(anchor.text_anchor, theme)
6800                .into_iter()
6801                .flat_map(|item| {
6802                    Some(OutlineItem {
6803                        depth: item.depth,
6804                        source_range_for_text: Anchor::range_in_buffer(
6805                            excerpt_id,
6806                            item.source_range_for_text,
6807                        ),
6808                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6809                        text: item.text,
6810                        highlight_ranges: item.highlight_ranges,
6811                        name_ranges: item.name_ranges,
6812                        body_range: item
6813                            .body_range
6814                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6815                        annotation_range: item
6816                            .annotation_range
6817                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6818                    })
6819                })
6820                .collect(),
6821        ))
6822    }
6823
6824    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6825        if id == ExcerptId::min() {
6826            Locator::min_ref()
6827        } else if id == ExcerptId::max() {
6828            Locator::max_ref()
6829        } else {
6830            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6831            if let Some(entry) = item
6832                && entry.id == id
6833            {
6834                return &entry.locator;
6835            }
6836            panic!("invalid excerpt id {id:?}")
6837        }
6838    }
6839
6840    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6841    fn excerpt_locators_for_ids(
6842        &self,
6843        ids: impl IntoIterator<Item = ExcerptId>,
6844    ) -> SmallVec<[Locator; 1]> {
6845        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6846        sorted_ids.sort_unstable();
6847        sorted_ids.dedup();
6848        let mut locators = SmallVec::new();
6849
6850        while sorted_ids.last() == Some(&ExcerptId::max()) {
6851            sorted_ids.pop();
6852            locators.push(Locator::max());
6853        }
6854
6855        let mut sorted_ids = sorted_ids.into_iter().peekable();
6856        locators.extend(
6857            sorted_ids
6858                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6859                .map(|_| Locator::min()),
6860        );
6861
6862        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6863        for id in sorted_ids {
6864            if cursor.seek_forward(&id, Bias::Left) {
6865                locators.push(cursor.item().unwrap().locator.clone());
6866            } else {
6867                panic!("invalid excerpt id {:?}", id);
6868            }
6869        }
6870
6871        locators.sort_unstable();
6872        locators
6873    }
6874
6875    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6876        Some(self.excerpt(excerpt_id)?.buffer_id)
6877    }
6878
6879    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6880        Some(&self.excerpt(excerpt_id)?.buffer)
6881    }
6882
6883    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6884        let mut cursor = self
6885            .excerpts
6886            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6887        let locator = self.excerpt_locator_for_id(excerpt_id);
6888        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6889        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6890            sought_exact = true;
6891            cursor.prev();
6892        } else if excerpt_id == ExcerptId::min() {
6893            sought_exact = true;
6894        }
6895        if sought_exact {
6896            let start = cursor.start().1;
6897            let end = cursor.end().1;
6898            let mut diff_transforms = self
6899                .diff_transforms
6900                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6901            diff_transforms.seek(&start, Bias::Left);
6902            let overshoot = start - diff_transforms.start().0;
6903            let start = diff_transforms.start().1 + overshoot;
6904            diff_transforms.seek(&end, Bias::Right);
6905            let overshoot = end - diff_transforms.start().0;
6906            let end = diff_transforms.start().1 + overshoot;
6907            Some(start.0..end.0)
6908        } else {
6909            None
6910        }
6911    }
6912
6913    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6914    /// to have the latest excerpt id for the one passed in and will also remap
6915    /// `ExcerptId::max()` to the corresponding excertp ID.
6916    ///
6917    /// Callers of this function should generally use the resulting excerpt's `id` field
6918    /// afterwards.
6919    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6920        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6921        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6922        let locator = self.excerpt_locator_for_id(excerpt_id);
6923        cursor.seek(&Some(locator), Bias::Left);
6924        if let Some(excerpt) = cursor.item()
6925            && excerpt.id == excerpt_id
6926        {
6927            return Some(excerpt);
6928        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6929            cursor.prev();
6930            return cursor.item();
6931        }
6932        None
6933    }
6934
6935    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6936    pub fn excerpt_containing<T: ToOffset>(
6937        &self,
6938        range: Range<T>,
6939    ) -> Option<MultiBufferExcerpt<'_>> {
6940        let range = range.start.to_offset(self)..range.end.to_offset(self);
6941        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6942        cursor.seek(&range.start);
6943
6944        let start_excerpt = cursor.excerpt()?;
6945        if range.end != range.start {
6946            cursor.seek_forward(&range.end);
6947            if cursor.excerpt()?.id != start_excerpt.id {
6948                return None;
6949            }
6950        }
6951
6952        cursor.seek_to_start_of_current_excerpt();
6953        let region = cursor.region()?;
6954        let offset = region.range.start;
6955        let buffer_offset = start_excerpt.buffer_start_offset();
6956        let excerpt_offset = *cursor.excerpts.start();
6957        Some(MultiBufferExcerpt {
6958            diff_transforms: cursor.diff_transforms,
6959            excerpt: start_excerpt,
6960            offset,
6961            buffer_offset,
6962            excerpt_offset,
6963        })
6964    }
6965
6966    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6967        if let Some(id) = anchor.text_anchor.buffer_id {
6968            return Some(id);
6969        }
6970        let excerpt = self.excerpt_containing(anchor..anchor)?;
6971        Some(excerpt.buffer_id())
6972    }
6973
6974    pub fn selections_in_range<'a>(
6975        &'a self,
6976        range: &'a Range<Anchor>,
6977        include_local: bool,
6978    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6979        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6980        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6981        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6982        cursor.seek(start_locator, Bias::Left);
6983        cursor
6984            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6985            .flat_map(move |excerpt| {
6986                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6987                if excerpt.id == range.start.excerpt_id {
6988                    query_range.start = range.start.text_anchor;
6989                }
6990                if excerpt.id == range.end.excerpt_id {
6991                    query_range.end = range.end.text_anchor;
6992                }
6993
6994                excerpt
6995                    .buffer
6996                    .selections_in_range(query_range, include_local)
6997                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6998                        selections.map(move |selection| {
6999                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7000                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7001                            if range.start.cmp(&start, self).is_gt() {
7002                                start = range.start;
7003                            }
7004                            if range.end.cmp(&end, self).is_lt() {
7005                                end = range.end;
7006                            }
7007
7008                            (
7009                                replica_id,
7010                                line_mode,
7011                                cursor_shape,
7012                                Selection {
7013                                    id: selection.id,
7014                                    start,
7015                                    end,
7016                                    reversed: selection.reversed,
7017                                    goal: selection.goal,
7018                                },
7019                            )
7020                        })
7021                    })
7022            })
7023    }
7024
7025    pub fn show_headers(&self) -> bool {
7026        self.show_headers
7027    }
7028
7029    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7030        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7031    }
7032
7033    pub fn all_diff_hunks_expanded(&self) -> bool {
7034        self.all_diff_hunks_expanded
7035    }
7036
7037    /// Visually annotates a position or range with the `Debug` representation of a value. The
7038    /// callsite of this function is used as a key - previous annotations will be removed.
7039    #[cfg(debug_assertions)]
7040    #[track_caller]
7041    pub fn debug<V, R>(&self, ranges: &R, value: V)
7042    where
7043        R: debug::ToMultiBufferDebugRanges,
7044        V: std::fmt::Debug,
7045    {
7046        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7047    }
7048
7049    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7050    /// debug annotations with the same key will be removed. The key is also used to determine the
7051    /// annotation's color.
7052    #[cfg(debug_assertions)]
7053    #[track_caller]
7054    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7055    where
7056        K: std::hash::Hash + 'static,
7057        R: debug::ToMultiBufferDebugRanges,
7058        V: std::fmt::Debug,
7059    {
7060        let text_ranges = ranges
7061            .to_multi_buffer_debug_ranges(self)
7062            .into_iter()
7063            .flat_map(|range| {
7064                self.range_to_buffer_ranges(range.start..=range.end)
7065                    .into_iter()
7066                    .map(|(buffer, range, _excerpt_id)| {
7067                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7068                    })
7069            })
7070            .collect();
7071        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7072            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7073        });
7074    }
7075
7076    fn excerpt_edits_for_diff_change(
7077        &self,
7078        buffer_state: &BufferState,
7079        diff_change_range: Range<usize>,
7080    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7081        let mut excerpt_edits = Vec::new();
7082        for locator in &buffer_state.excerpts {
7083            let mut cursor = self
7084                .excerpts
7085                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7086            cursor.seek_forward(&Some(locator), Bias::Left);
7087            if let Some(excerpt) = cursor.item()
7088                && excerpt.locator == *locator
7089            {
7090                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7091                if diff_change_range.end < excerpt_buffer_range.start
7092                    || diff_change_range.start > excerpt_buffer_range.end
7093                {
7094                    continue;
7095                }
7096                let excerpt_start = cursor.start().1;
7097                let excerpt_len = excerpt.text_summary.len;
7098                let diff_change_start_in_excerpt = diff_change_range
7099                    .start
7100                    .saturating_sub(excerpt_buffer_range.start);
7101                let diff_change_end_in_excerpt = diff_change_range
7102                    .end
7103                    .saturating_sub(excerpt_buffer_range.start);
7104                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7105                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7106                excerpt_edits.push(Edit {
7107                    old: edit_start..edit_end,
7108                    new: edit_start..edit_end,
7109                });
7110            }
7111        }
7112        excerpt_edits
7113    }
7114}
7115
7116#[cfg(any(test, feature = "test-support"))]
7117impl MultiBufferSnapshot {
7118    pub fn random_byte_range(
7119        &self,
7120        start_offset: MultiBufferOffset,
7121        rng: &mut impl rand::Rng,
7122    ) -> Range<MultiBufferOffset> {
7123        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7124        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7125        start..end
7126    }
7127
7128    #[cfg(any(test, feature = "test-support"))]
7129    fn check_invariants(&self) {
7130        let excerpts = self.excerpts.items(());
7131        let excerpt_ids = self.excerpt_ids.items(());
7132
7133        for (ix, excerpt) in excerpts.iter().enumerate() {
7134            if ix == 0 {
7135                if excerpt.locator <= Locator::min() {
7136                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7137                }
7138            } else if excerpt.locator <= excerpts[ix - 1].locator {
7139                panic!("excerpts are out-of-order: {:?}", excerpts);
7140            }
7141        }
7142
7143        for (ix, entry) in excerpt_ids.iter().enumerate() {
7144            if ix == 0 {
7145                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7146                    panic!("invalid first excerpt id {:?}", entry.id);
7147                }
7148            } else if entry.id <= excerpt_ids[ix - 1].id {
7149                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7150            }
7151        }
7152
7153        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7154            panic!(
7155                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7156                self.excerpts.summary().text,
7157                self.diff_transforms.summary().input,
7158                self.diff_transforms.items(()),
7159            );
7160        }
7161
7162        let mut prev_transform: Option<&DiffTransform> = None;
7163        for item in self.diff_transforms.iter() {
7164            if let DiffTransform::BufferContent {
7165                summary,
7166                inserted_hunk_info,
7167            } = item
7168            {
7169                if let Some(DiffTransform::BufferContent {
7170                    inserted_hunk_info: prev_inserted_hunk_info,
7171                    ..
7172                }) = prev_transform
7173                    && *inserted_hunk_info == *prev_inserted_hunk_info
7174                {
7175                    panic!(
7176                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7177                        self.diff_transforms.items(())
7178                    );
7179                }
7180                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7181                    panic!("empty buffer content transform");
7182                }
7183            }
7184            prev_transform = Some(item);
7185        }
7186    }
7187}
7188
7189impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7190where
7191    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7192    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7193{
7194    #[instrument(skip_all)]
7195    fn seek(&mut self, position: &MBD) {
7196        let position = OutputDimension(*position);
7197        self.cached_region.take();
7198        self.diff_transforms.seek(&position, Bias::Right);
7199        if self.diff_transforms.item().is_none()
7200            && self.diff_transforms.start().output_dimension == position
7201        {
7202            self.diff_transforms.prev();
7203        }
7204
7205        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7206        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7207            let overshoot = position - self.diff_transforms.start().output_dimension;
7208            excerpt_position += overshoot;
7209        }
7210
7211        self.excerpts.seek(&excerpt_position, Bias::Right);
7212        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7213            self.excerpts.prev();
7214        }
7215    }
7216
7217    fn seek_forward(&mut self, position: &MBD) {
7218        let position = OutputDimension(*position);
7219        self.cached_region.take();
7220        self.diff_transforms.seek_forward(&position, Bias::Right);
7221        if self.diff_transforms.item().is_none()
7222            && self.diff_transforms.start().output_dimension == position
7223        {
7224            self.diff_transforms.prev();
7225        }
7226
7227        let overshoot = position - self.diff_transforms.start().output_dimension;
7228        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7229        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7230            excerpt_position += overshoot;
7231        }
7232
7233        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7234        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7235            self.excerpts.prev();
7236        }
7237    }
7238
7239    fn next_excerpt(&mut self) {
7240        self.excerpts.next();
7241        self.seek_to_start_of_current_excerpt();
7242    }
7243
7244    fn prev_excerpt(&mut self) {
7245        self.excerpts.prev();
7246        self.seek_to_start_of_current_excerpt();
7247    }
7248
7249    fn seek_to_start_of_current_excerpt(&mut self) {
7250        self.cached_region.take();
7251
7252        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7253            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7254            && self.diff_transforms.next_item().is_some()
7255        {
7256            self.diff_transforms.next();
7257        }
7258    }
7259
7260    fn next_excerpt_forwards(&mut self) {
7261        self.excerpts.next();
7262        self.seek_to_start_of_current_excerpt_forward();
7263    }
7264
7265    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7266        self.cached_region.take();
7267
7268        if self
7269            .diff_transforms
7270            .seek_forward(self.excerpts.start(), Bias::Left)
7271            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7272            && self.diff_transforms.next_item().is_some()
7273        {
7274            self.diff_transforms.next();
7275        }
7276    }
7277
7278    fn next(&mut self) {
7279        self.cached_region.take();
7280        match self
7281            .diff_transforms
7282            .end()
7283            .excerpt_dimension
7284            .cmp(&self.excerpts.end())
7285        {
7286            cmp::Ordering::Less => self.diff_transforms.next(),
7287            cmp::Ordering::Greater => self.excerpts.next(),
7288            cmp::Ordering::Equal => {
7289                self.diff_transforms.next();
7290                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7291                    || self.diff_transforms.item().is_none()
7292                {
7293                    self.excerpts.next();
7294                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7295                    self.diff_transforms.item()
7296                    && self
7297                        .excerpts
7298                        .item()
7299                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7300                {
7301                    self.excerpts.next();
7302                }
7303            }
7304        }
7305    }
7306
7307    fn prev(&mut self) {
7308        self.cached_region.take();
7309        match self
7310            .diff_transforms
7311            .start()
7312            .excerpt_dimension
7313            .cmp(self.excerpts.start())
7314        {
7315            cmp::Ordering::Less => self.excerpts.prev(),
7316            cmp::Ordering::Greater => self.diff_transforms.prev(),
7317            cmp::Ordering::Equal => {
7318                self.diff_transforms.prev();
7319                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7320                    || self.diff_transforms.item().is_none()
7321                {
7322                    self.excerpts.prev();
7323                }
7324            }
7325        }
7326    }
7327
7328    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7329        self.cached_region
7330            .get_or_init(|| self.build_region())
7331            .as_ref()
7332    }
7333
7334    fn is_at_start_of_excerpt(&mut self) -> bool {
7335        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7336            return false;
7337        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7338            return true;
7339        }
7340
7341        self.diff_transforms.prev();
7342        let prev_transform = self.diff_transforms.item();
7343        self.diff_transforms.next();
7344
7345        prev_transform.is_none_or(|next_transform| {
7346            matches!(next_transform, DiffTransform::BufferContent { .. })
7347        })
7348    }
7349
7350    fn is_at_end_of_excerpt(&self) -> bool {
7351        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7352            return false;
7353        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7354            || self.diff_transforms.item().is_none()
7355        {
7356            return true;
7357        }
7358
7359        let next_transform = self.diff_transforms.next_item();
7360        next_transform.is_none_or(|next_transform| match next_transform {
7361            DiffTransform::BufferContent { .. } => true,
7362            DiffTransform::DeletedHunk { hunk_info, .. } => self
7363                .excerpts
7364                .item()
7365                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7366        })
7367    }
7368
7369    fn main_buffer_position(&self) -> Option<BD> {
7370        let excerpt = self.excerpts.item()?;
7371        let buffer = &excerpt.buffer;
7372        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7373        let mut buffer_start = buffer_context_start;
7374        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7375        buffer_start += overshoot;
7376        Some(buffer_start)
7377    }
7378
7379    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7380        let excerpt = self.excerpts.item()?;
7381        match self.diff_transforms.item()? {
7382            DiffTransform::DeletedHunk {
7383                buffer_id,
7384                base_text_byte_range,
7385                has_trailing_newline,
7386                hunk_info,
7387                ..
7388            } => {
7389                let diff = self.diffs.get(buffer_id)?;
7390                let buffer = diff.base_text();
7391                let mut rope_cursor = buffer.as_rope().cursor(0);
7392                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7393                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7394                let mut buffer_end = buffer_start;
7395                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7396                let start = self.diff_transforms.start().output_dimension.0;
7397                let end = self.diff_transforms.end().output_dimension.0;
7398                Some(MultiBufferRegion {
7399                    buffer,
7400                    excerpt,
7401                    has_trailing_newline: *has_trailing_newline,
7402                    is_main_buffer: false,
7403                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7404                        hunk_info.hunk_secondary_status,
7405                    )),
7406                    buffer_range: buffer_start..buffer_end,
7407                    range: start..end,
7408                })
7409            }
7410            DiffTransform::BufferContent {
7411                inserted_hunk_info, ..
7412            } => {
7413                let buffer = &excerpt.buffer;
7414                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7415
7416                let mut start = self.diff_transforms.start().output_dimension.0;
7417                let mut buffer_start = buffer_context_start;
7418                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7419                    let overshoot =
7420                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7421                    start += overshoot;
7422                } else {
7423                    let overshoot =
7424                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7425                    buffer_start += overshoot;
7426                }
7427
7428                let mut end;
7429                let mut buffer_end;
7430                let has_trailing_newline;
7431                let transform_end = self.diff_transforms.end();
7432                if transform_end.excerpt_dimension < self.excerpts.end() {
7433                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7434                    end = transform_end.output_dimension.0;
7435                    buffer_end = buffer_context_start;
7436                    buffer_end += overshoot;
7437                    has_trailing_newline = false;
7438                } else {
7439                    let overshoot =
7440                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7441                    end = self.diff_transforms.start().output_dimension.0;
7442                    end += overshoot;
7443                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7444                    has_trailing_newline = excerpt.has_trailing_newline;
7445                };
7446
7447                let diff_hunk_status = inserted_hunk_info.map(|info| {
7448                    if info.is_logically_deleted {
7449                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7450                    } else {
7451                        DiffHunkStatus::added(info.hunk_secondary_status)
7452                    }
7453                });
7454
7455                Some(MultiBufferRegion {
7456                    buffer,
7457                    excerpt,
7458                    has_trailing_newline,
7459                    is_main_buffer: true,
7460                    diff_hunk_status,
7461                    buffer_range: buffer_start..buffer_end,
7462                    range: start..end,
7463                })
7464            }
7465        }
7466    }
7467
7468    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7469        let excerpt = self.excerpts.item()?;
7470        match self.diff_transforms.item()? {
7471            &DiffTransform::DeletedHunk { .. } => {
7472                let start = self.diff_transforms.start().output_dimension.0;
7473                let end = self.diff_transforms.end().output_dimension.0;
7474                Some((excerpt, start..end))
7475            }
7476            DiffTransform::BufferContent { .. } => {
7477                let mut start = self.diff_transforms.start().output_dimension.0;
7478                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7479                    let overshoot =
7480                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7481                    start += overshoot;
7482                }
7483
7484                let mut end;
7485                let transform_end = self.diff_transforms.end();
7486                if transform_end.excerpt_dimension < self.excerpts.end() {
7487                    end = transform_end.output_dimension.0;
7488                } else {
7489                    let overshoot =
7490                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7491                    end = self.diff_transforms.start().output_dimension.0;
7492                    end += overshoot;
7493                };
7494
7495                Some((excerpt, start..end))
7496            }
7497        }
7498    }
7499
7500    fn excerpt(&self) -> Option<&'a Excerpt> {
7501        self.excerpts.item()
7502    }
7503}
7504
7505impl Excerpt {
7506    fn new(
7507        id: ExcerptId,
7508        locator: Locator,
7509        buffer_id: BufferId,
7510        buffer: Arc<BufferSnapshot>,
7511        range: ExcerptRange<text::Anchor>,
7512        has_trailing_newline: bool,
7513    ) -> Self {
7514        Excerpt {
7515            id,
7516            locator,
7517            max_buffer_row: range.context.end.to_point(&buffer).row,
7518            text_summary: buffer
7519                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7520            buffer_id,
7521            buffer,
7522            range,
7523            has_trailing_newline,
7524        }
7525    }
7526
7527    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7528        let content_start = self.range.context.start.to_offset(&self.buffer);
7529        let chunks_start = content_start + range.start;
7530        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7531
7532        let has_footer = self.has_trailing_newline
7533            && range.start <= self.text_summary.len
7534            && range.end > self.text_summary.len;
7535
7536        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7537
7538        ExcerptChunks {
7539            excerpt_id: self.id,
7540            content_chunks,
7541            has_footer,
7542        }
7543    }
7544
7545    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7546        let content_start = self.range.context.start.to_offset(&self.buffer);
7547        let chunks_start = content_start + range.start;
7548        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7549        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7550        excerpt_chunks.has_footer = self.has_trailing_newline
7551            && range.start <= self.text_summary.len
7552            && range.end > self.text_summary.len;
7553    }
7554
7555    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7556        if text_anchor
7557            .cmp(&self.range.context.start, &self.buffer)
7558            .is_lt()
7559        {
7560            self.range.context.start
7561        } else if text_anchor
7562            .cmp(&self.range.context.end, &self.buffer)
7563            .is_gt()
7564        {
7565            self.range.context.end
7566        } else {
7567            text_anchor
7568        }
7569    }
7570
7571    fn contains(&self, anchor: &Anchor) -> bool {
7572        (anchor.text_anchor.buffer_id == None
7573            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7574            && self
7575                .range
7576                .context
7577                .start
7578                .cmp(&anchor.text_anchor, &self.buffer)
7579                .is_le()
7580            && self
7581                .range
7582                .context
7583                .end
7584                .cmp(&anchor.text_anchor, &self.buffer)
7585                .is_ge()
7586    }
7587
7588    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7589    fn buffer_start_offset(&self) -> BufferOffset {
7590        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7591    }
7592
7593    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7594    fn buffer_end_offset(&self) -> BufferOffset {
7595        self.buffer_start_offset() + self.text_summary.len
7596    }
7597}
7598
7599impl<'a> MultiBufferExcerpt<'a> {
7600    pub fn id(&self) -> ExcerptId {
7601        self.excerpt.id
7602    }
7603
7604    pub fn buffer_id(&self) -> BufferId {
7605        self.excerpt.buffer_id
7606    }
7607
7608    pub fn start_anchor(&self) -> Anchor {
7609        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7610    }
7611
7612    pub fn end_anchor(&self) -> Anchor {
7613        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7614    }
7615
7616    pub fn buffer(&self) -> &'a BufferSnapshot {
7617        &self.excerpt.buffer
7618    }
7619
7620    pub fn buffer_range(&self) -> Range<BufferOffset> {
7621        self.buffer_offset
7622            ..BufferOffset(
7623                self.excerpt
7624                    .range
7625                    .context
7626                    .end
7627                    .to_offset(&self.excerpt.buffer.text),
7628            )
7629    }
7630
7631    pub fn start_offset(&self) -> MultiBufferOffset {
7632        self.offset
7633    }
7634
7635    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7636    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7637        self.map_range_to_buffer(offset..offset).start
7638    }
7639
7640    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7641    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7642        self.diff_transforms
7643            .seek(&OutputDimension(range.start), Bias::Right);
7644        let start = self.map_offset_to_buffer_internal(range.start);
7645        let end = if range.end > range.start {
7646            self.diff_transforms
7647                .seek_forward(&OutputDimension(range.end), Bias::Right);
7648            self.map_offset_to_buffer_internal(range.end)
7649        } else {
7650            start
7651        };
7652        start..end
7653    }
7654
7655    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7656        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7657        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7658            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7659        };
7660        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7661        self.buffer_offset + offset_in_excerpt
7662    }
7663
7664    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7665    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7666        self.map_range_from_buffer(buffer_offset..buffer_offset)
7667            .start
7668    }
7669
7670    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7671    pub fn map_range_from_buffer(
7672        &mut self,
7673        buffer_range: Range<BufferOffset>,
7674    ) -> Range<MultiBufferOffset> {
7675        if buffer_range.start < self.buffer_offset {
7676            log::warn!(
7677                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7678            );
7679            return self.offset..self.offset;
7680        }
7681        let overshoot = buffer_range.start - self.buffer_offset;
7682        let excerpt_offset = self.excerpt_offset + overshoot;
7683        let excerpt_seek_dim = excerpt_offset;
7684        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7685        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7686            log::warn!(
7687                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7688            );
7689            return self.offset..self.offset;
7690        }
7691        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7692        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7693
7694        let end = if buffer_range.start < buffer_range.end {
7695            let overshoot = buffer_range.end - self.buffer_offset;
7696            let excerpt_offset = self.excerpt_offset + overshoot;
7697            let excerpt_seek_dim = excerpt_offset;
7698            self.diff_transforms
7699                .seek_forward(&excerpt_seek_dim, Bias::Right);
7700            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7701            // todo(lw): Clamp end to the excerpt boundaries
7702            self.diff_transforms.start().output_dimension.0 + overshoot
7703        } else {
7704            start
7705        };
7706
7707        start..end
7708    }
7709
7710    /// Returns true if the entirety of the given range is in the buffer's excerpt
7711    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7712        range.start >= self.excerpt.buffer_start_offset()
7713            && range.end <= self.excerpt.buffer_end_offset()
7714    }
7715
7716    /// Returns true if any part of the given range is in the buffer's excerpt
7717    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7718        range.start <= self.excerpt.buffer_end_offset()
7719            && range.end >= self.excerpt.buffer_start_offset()
7720    }
7721
7722    pub fn max_buffer_row(&self) -> u32 {
7723        self.excerpt.max_buffer_row
7724    }
7725}
7726
7727impl ExcerptId {
7728    pub fn min() -> Self {
7729        Self(0)
7730    }
7731
7732    pub fn max() -> Self {
7733        Self(u32::MAX)
7734    }
7735
7736    pub fn to_proto(self) -> u64 {
7737        self.0 as _
7738    }
7739
7740    pub fn from_proto(proto: u64) -> Self {
7741        Self(proto as _)
7742    }
7743
7744    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7745        let a = snapshot.excerpt_locator_for_id(*self);
7746        let b = snapshot.excerpt_locator_for_id(*other);
7747        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7748    }
7749}
7750
7751impl From<ExcerptId> for usize {
7752    fn from(val: ExcerptId) -> Self {
7753        val.0 as usize
7754    }
7755}
7756
7757impl fmt::Debug for Excerpt {
7758    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7759        f.debug_struct("Excerpt")
7760            .field("id", &self.id)
7761            .field("locator", &self.locator)
7762            .field("buffer_id", &self.buffer_id)
7763            .field("range", &self.range)
7764            .field("text_summary", &self.text_summary)
7765            .field("has_trailing_newline", &self.has_trailing_newline)
7766            .finish()
7767    }
7768}
7769
7770impl sum_tree::Item for Excerpt {
7771    type Summary = ExcerptSummary;
7772
7773    fn summary(&self, _cx: ()) -> Self::Summary {
7774        let mut text = self.text_summary;
7775        if self.has_trailing_newline {
7776            text += TextSummary::from("\n");
7777        }
7778        ExcerptSummary {
7779            excerpt_id: self.id,
7780            excerpt_locator: self.locator.clone(),
7781            widest_line_number: self.max_buffer_row,
7782            text: text.into(),
7783        }
7784    }
7785}
7786
7787impl sum_tree::Item for ExcerptIdMapping {
7788    type Summary = ExcerptId;
7789
7790    fn summary(&self, _cx: ()) -> Self::Summary {
7791        self.id
7792    }
7793}
7794
7795impl sum_tree::KeyedItem for ExcerptIdMapping {
7796    type Key = ExcerptId;
7797
7798    fn key(&self) -> Self::Key {
7799        self.id
7800    }
7801}
7802
7803impl DiffTransform {
7804    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7805        match self {
7806            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7807            DiffTransform::BufferContent {
7808                inserted_hunk_info, ..
7809            } => *inserted_hunk_info,
7810        }
7811    }
7812}
7813
7814impl sum_tree::Item for DiffTransform {
7815    type Summary = DiffTransformSummary;
7816
7817    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7818        match self {
7819            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7820                input: *summary,
7821                output: *summary,
7822            },
7823            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7824                input: MBTextSummary::default(),
7825                output: summary.into(),
7826            },
7827        }
7828    }
7829}
7830
7831impl DiffTransformSummary {
7832    fn excerpt_len(&self) -> ExcerptOffset {
7833        ExcerptDimension(self.input.len)
7834    }
7835}
7836
7837impl sum_tree::ContextLessSummary for DiffTransformSummary {
7838    fn zero() -> Self {
7839        DiffTransformSummary {
7840            input: MBTextSummary::default(),
7841            output: MBTextSummary::default(),
7842        }
7843    }
7844
7845    fn add_summary(&mut self, other: &Self) {
7846        self.input += other.input;
7847        self.output += other.output;
7848    }
7849}
7850
7851impl sum_tree::ContextLessSummary for ExcerptId {
7852    fn zero() -> Self {
7853        Self(0)
7854    }
7855
7856    fn add_summary(&mut self, summary: &Self) {
7857        *self = cmp::max(*self, *summary);
7858    }
7859}
7860
7861impl sum_tree::ContextLessSummary for ExcerptSummary {
7862    fn zero() -> Self {
7863        Self::default()
7864    }
7865
7866    fn add_summary(&mut self, summary: &Self) {
7867        debug_assert!(
7868            summary.excerpt_locator > self.excerpt_locator
7869                || self.excerpt_locator == Locator::min(),
7870            "Excerpt locators must be in ascending order: {:?} > {:?}",
7871            summary.excerpt_locator,
7872            self.excerpt_locator
7873        );
7874        self.excerpt_locator = summary.excerpt_locator.clone();
7875        self.text += summary.text;
7876        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7877    }
7878}
7879
7880impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7881    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7882        Ord::cmp(&Some(self), cursor_location)
7883    }
7884}
7885
7886impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7887    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7888        Ord::cmp(self, &cursor_location.excerpt_locator)
7889    }
7890}
7891
7892impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7893where
7894    MBD: MultiBufferDimension + Default,
7895{
7896    fn zero(_: ()) -> Self {
7897        ExcerptDimension(MBD::default())
7898    }
7899
7900    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7901        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7902    }
7903}
7904
7905impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7906    fn zero(_cx: ()) -> Self {
7907        Default::default()
7908    }
7909
7910    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7911        *self = Some(&summary.excerpt_locator);
7912    }
7913}
7914
7915impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7916    fn zero(_cx: ()) -> Self {
7917        Default::default()
7918    }
7919
7920    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7921        *self = Some(summary.excerpt_id);
7922    }
7923}
7924
7925#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7926struct OutputDimension<T>(T);
7927
7928impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7929    fn eq(&self, other: &T) -> bool {
7930        self.0 == *other
7931    }
7932}
7933
7934impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7935    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7936        self.0.partial_cmp(other)
7937    }
7938}
7939
7940impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7941where
7942    T: ops::Sub<U, Output = R>,
7943{
7944    type Output = R;
7945
7946    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7947        self.0 - other.0
7948    }
7949}
7950
7951impl<R, T, U> ops::Add<U> for OutputDimension<T>
7952where
7953    T: ops::Add<U, Output = R>,
7954{
7955    type Output = OutputDimension<R>;
7956
7957    fn add(self, other: U) -> Self::Output {
7958        OutputDimension(self.0 + other)
7959    }
7960}
7961
7962impl<T, U> AddAssign<U> for OutputDimension<T>
7963where
7964    T: AddAssign<U>,
7965{
7966    fn add_assign(&mut self, other: U) {
7967        self.0 += other;
7968    }
7969}
7970
7971impl<T, U> SubAssign<U> for OutputDimension<T>
7972where
7973    T: SubAssign<U>,
7974{
7975    fn sub_assign(&mut self, other: U) {
7976        self.0 -= other;
7977    }
7978}
7979
7980#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7981struct ExcerptDimension<T>(T);
7982
7983impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7984    fn eq(&self, other: &T) -> bool {
7985        self.0 == *other
7986    }
7987}
7988
7989impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7990    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7991        self.0.partial_cmp(other)
7992    }
7993}
7994
7995impl ExcerptOffset {
7996    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7997        self.0.saturating_sub(other.0)
7998    }
7999}
8000
8001impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8002where
8003    T: ops::Sub<U, Output = R>,
8004{
8005    type Output = R;
8006
8007    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8008        self.0 - other.0
8009    }
8010}
8011
8012impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8013where
8014    T: ops::Add<U, Output = R>,
8015{
8016    type Output = ExcerptDimension<R>;
8017
8018    fn add(self, other: U) -> Self::Output {
8019        ExcerptDimension(self.0 + other)
8020    }
8021}
8022
8023impl<T, U> AddAssign<U> for ExcerptDimension<T>
8024where
8025    T: AddAssign<U>,
8026{
8027    fn add_assign(&mut self, other: U) {
8028        self.0 += other;
8029    }
8030}
8031
8032impl<T, U> SubAssign<U> for ExcerptDimension<T>
8033where
8034    T: SubAssign<U>,
8035{
8036    fn sub_assign(&mut self, other: U) {
8037        self.0 -= other;
8038    }
8039}
8040
8041impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8042    fn zero(_: ()) -> Self {
8043        MultiBufferOffset::ZERO
8044    }
8045
8046    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8047        *self += summary.output.len;
8048    }
8049}
8050
8051impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8052    for ExcerptDimension<MBD>
8053where
8054    MBD: MultiBufferDimension + Ord,
8055{
8056    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8057        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8058    }
8059}
8060
8061impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8062    for ExcerptDimension<MBD>
8063where
8064    MBD: MultiBufferDimension + Ord,
8065{
8066    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8067        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8068    }
8069}
8070
8071impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8072    for ExcerptDimension<MBD>
8073{
8074    fn zero(_: ()) -> Self {
8075        ExcerptDimension(MBD::default())
8076    }
8077
8078    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8079        self.0.add_mb_text_summary(&summary.input)
8080    }
8081}
8082
8083impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8084    for OutputDimension<MBD>
8085where
8086    MBD: MultiBufferDimension + Ord,
8087{
8088    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8089        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8090    }
8091}
8092
8093impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8094    for OutputDimension<MBD>
8095{
8096    fn zero(_: ()) -> Self {
8097        OutputDimension(MBD::default())
8098    }
8099
8100    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8101        self.0.add_mb_text_summary(&summary.output)
8102    }
8103}
8104
8105impl MultiBufferRows<'_> {
8106    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8107        self.point = Point::new(row, 0);
8108        self.cursor.seek(&self.point);
8109    }
8110}
8111
8112impl Iterator for MultiBufferRows<'_> {
8113    type Item = RowInfo;
8114
8115    fn next(&mut self) -> Option<Self::Item> {
8116        if self.is_empty && self.point.row == 0 {
8117            self.point += Point::new(1, 0);
8118            return Some(RowInfo {
8119                buffer_id: None,
8120                buffer_row: Some(0),
8121                multibuffer_row: Some(MultiBufferRow(0)),
8122                diff_status: None,
8123                expand_info: None,
8124                wrapped_buffer_row: None,
8125            });
8126        }
8127
8128        let mut region = self.cursor.region()?.clone();
8129        while self.point >= region.range.end {
8130            self.cursor.next();
8131            if let Some(next_region) = self.cursor.region() {
8132                region = next_region.clone();
8133            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8134                let multibuffer_row = MultiBufferRow(self.point.row);
8135                let last_excerpt = self
8136                    .cursor
8137                    .excerpts
8138                    .item()
8139                    .or(self.cursor.excerpts.prev_item())?;
8140                let last_row = last_excerpt
8141                    .range
8142                    .context
8143                    .end
8144                    .to_point(&last_excerpt.buffer)
8145                    .row;
8146
8147                let first_row = last_excerpt
8148                    .range
8149                    .context
8150                    .start
8151                    .to_point(&last_excerpt.buffer)
8152                    .row;
8153
8154                let expand_info = if self.is_singleton {
8155                    None
8156                } else {
8157                    let needs_expand_up = first_row == last_row
8158                        && last_row > 0
8159                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8160                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8161
8162                    if needs_expand_up && needs_expand_down {
8163                        Some(ExpandExcerptDirection::UpAndDown)
8164                    } else if needs_expand_up {
8165                        Some(ExpandExcerptDirection::Up)
8166                    } else if needs_expand_down {
8167                        Some(ExpandExcerptDirection::Down)
8168                    } else {
8169                        None
8170                    }
8171                    .map(|direction| ExpandInfo {
8172                        direction,
8173                        excerpt_id: last_excerpt.id,
8174                    })
8175                };
8176                self.point += Point::new(1, 0);
8177                return Some(RowInfo {
8178                    buffer_id: Some(last_excerpt.buffer_id),
8179                    buffer_row: Some(last_row),
8180                    multibuffer_row: Some(multibuffer_row),
8181                    diff_status: None,
8182                    wrapped_buffer_row: None,
8183                    expand_info,
8184                });
8185            } else {
8186                return None;
8187            };
8188        }
8189
8190        let overshoot = self.point - region.range.start;
8191        let buffer_point = region.buffer_range.start + overshoot;
8192        let expand_info = if self.is_singleton {
8193            None
8194        } else {
8195            let needs_expand_up = self.point.row == region.range.start.row
8196                && self.cursor.is_at_start_of_excerpt()
8197                && buffer_point.row > 0;
8198            let needs_expand_down = (region.excerpt.has_trailing_newline
8199                && self.point.row + 1 == region.range.end.row
8200                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8201                && self.cursor.is_at_end_of_excerpt()
8202                && buffer_point.row < region.buffer.max_point().row;
8203
8204            if needs_expand_up && needs_expand_down {
8205                Some(ExpandExcerptDirection::UpAndDown)
8206            } else if needs_expand_up {
8207                Some(ExpandExcerptDirection::Up)
8208            } else if needs_expand_down {
8209                Some(ExpandExcerptDirection::Down)
8210            } else {
8211                None
8212            }
8213            .map(|direction| ExpandInfo {
8214                direction,
8215                excerpt_id: region.excerpt.id,
8216            })
8217        };
8218
8219        let result = Some(RowInfo {
8220            buffer_id: Some(region.buffer.remote_id()),
8221            buffer_row: Some(buffer_point.row),
8222            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8223            diff_status: region
8224                .diff_hunk_status
8225                .filter(|_| self.point < region.range.end),
8226            expand_info,
8227            wrapped_buffer_row: None,
8228        });
8229        self.point += Point::new(1, 0);
8230        result
8231    }
8232}
8233
8234impl<'a> MultiBufferChunks<'a> {
8235    pub fn offset(&self) -> MultiBufferOffset {
8236        self.range.start
8237    }
8238
8239    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8240        self.diff_transforms.seek(&range.end, Bias::Right);
8241        let mut excerpt_end = self.diff_transforms.start().1;
8242        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8243            let overshoot = range.end - self.diff_transforms.start().0;
8244            excerpt_end += overshoot;
8245        }
8246
8247        self.diff_transforms.seek(&range.start, Bias::Right);
8248        let mut excerpt_start = self.diff_transforms.start().1;
8249        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8250            let overshoot = range.start - self.diff_transforms.start().0;
8251            excerpt_start += overshoot;
8252        }
8253
8254        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8255        self.buffer_chunk.take();
8256        self.range = range;
8257    }
8258
8259    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8260        self.excerpt_offset_range = new_range.clone();
8261        self.excerpts.seek(&new_range.start, Bias::Right);
8262        if let Some(excerpt) = self.excerpts.item() {
8263            let excerpt_start = *self.excerpts.start();
8264            if let Some(excerpt_chunks) = self
8265                .excerpt_chunks
8266                .as_mut()
8267                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8268            {
8269                excerpt.seek_chunks(
8270                    excerpt_chunks,
8271                    (self.excerpt_offset_range.start - excerpt_start)
8272                        ..(self.excerpt_offset_range.end - excerpt_start),
8273                );
8274            } else {
8275                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8276                    (self.excerpt_offset_range.start - excerpt_start)
8277                        ..(self.excerpt_offset_range.end - excerpt_start),
8278                    self.language_aware,
8279                ));
8280            }
8281        } else {
8282            self.excerpt_chunks = None;
8283        }
8284    }
8285
8286    #[ztracing::instrument(skip_all)]
8287    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8288        loop {
8289            if self.excerpt_offset_range.is_empty() {
8290                return None;
8291            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8292                self.excerpt_offset_range.start += chunk.text.len();
8293                return Some(chunk);
8294            } else {
8295                self.excerpts.next();
8296                let excerpt = self.excerpts.item()?;
8297                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8298                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8299                    self.language_aware,
8300                ));
8301            }
8302        }
8303    }
8304}
8305
8306impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8307    type Item = &'a str;
8308
8309    fn next(&mut self) -> Option<Self::Item> {
8310        let mut region = self.cursor.region()?;
8311        if self.offset == region.range.start {
8312            self.cursor.prev();
8313            region = self.cursor.region()?;
8314            let start_overshoot = self.start.saturating_sub(region.range.start);
8315            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8316                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8317            ));
8318        }
8319
8320        if self.offset == region.range.end && region.has_trailing_newline {
8321            self.offset -= 1;
8322            Some("\n")
8323        } else {
8324            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8325            self.offset -= chunk.len();
8326            Some(chunk)
8327        }
8328    }
8329}
8330
8331impl<'a> Iterator for MultiBufferChunks<'a> {
8332    type Item = Chunk<'a>;
8333
8334    #[ztracing::instrument(skip_all)]
8335    fn next(&mut self) -> Option<Chunk<'a>> {
8336        if self.range.start >= self.range.end {
8337            return None;
8338        }
8339        if self.range.start == self.diff_transforms.end().0 {
8340            self.diff_transforms.next();
8341        }
8342
8343        let diff_transform_start = self.diff_transforms.start().0;
8344        let diff_transform_end = self.diff_transforms.end().0;
8345        debug_assert!(
8346            self.range.start < diff_transform_end,
8347            "{:?} < {:?} of ({1:?}..{2:?})",
8348            self.range.start,
8349            diff_transform_end,
8350            diff_transform_start
8351        );
8352
8353        let diff_transform = self.diff_transforms.item()?;
8354        match diff_transform {
8355            DiffTransform::BufferContent { .. } => {
8356                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8357                    chunk
8358                } else {
8359                    let chunk = self.next_excerpt_chunk().unwrap();
8360                    self.buffer_chunk.insert(chunk)
8361                };
8362
8363                let chunk_end = self.range.start + chunk.text.len();
8364                let diff_transform_end = diff_transform_end.min(self.range.end);
8365
8366                if diff_transform_end < chunk_end {
8367                    let split_idx = diff_transform_end - self.range.start;
8368                    let (before, after) = chunk.text.split_at(split_idx);
8369                    self.range.start = diff_transform_end;
8370                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8371                    let chars = chunk.chars & mask;
8372                    let tabs = chunk.tabs & mask;
8373
8374                    chunk.text = after;
8375                    chunk.chars = chunk.chars >> split_idx;
8376                    chunk.tabs = chunk.tabs >> split_idx;
8377
8378                    Some(Chunk {
8379                        text: before,
8380                        chars,
8381                        tabs,
8382                        ..chunk.clone()
8383                    })
8384                } else {
8385                    self.range.start = chunk_end;
8386                    self.buffer_chunk.take()
8387                }
8388            }
8389            DiffTransform::DeletedHunk {
8390                buffer_id,
8391                base_text_byte_range,
8392                has_trailing_newline,
8393                ..
8394            } => {
8395                let base_text_start =
8396                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8397                let base_text_end =
8398                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8399                let base_text_end = base_text_end.min(base_text_byte_range.end);
8400
8401                let mut chunks = if let Some((_, mut chunks)) = self
8402                    .diff_base_chunks
8403                    .take()
8404                    .filter(|(id, _)| id == buffer_id)
8405                {
8406                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8407                    {
8408                        chunks.seek(base_text_start..base_text_end);
8409                    }
8410                    chunks
8411                } else {
8412                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8413                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8414                };
8415
8416                let chunk = if let Some(chunk) = chunks.next() {
8417                    self.range.start += chunk.text.len();
8418                    self.diff_base_chunks = Some((*buffer_id, chunks));
8419                    chunk
8420                } else {
8421                    debug_assert!(has_trailing_newline);
8422                    self.range.start += "\n".len();
8423                    Chunk {
8424                        text: "\n",
8425                        chars: 1u128,
8426                        ..Default::default()
8427                    }
8428                };
8429                Some(chunk)
8430            }
8431        }
8432    }
8433}
8434
8435impl MultiBufferBytes<'_> {
8436    fn consume(&mut self, len: usize) {
8437        self.range.start += len;
8438        self.chunk = &self.chunk[len..];
8439
8440        if !self.range.is_empty() && self.chunk.is_empty() {
8441            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8442                self.chunk = chunk;
8443            } else if self.has_trailing_newline {
8444                self.has_trailing_newline = false;
8445                self.chunk = b"\n";
8446            } else {
8447                self.cursor.next();
8448                if let Some(region) = self.cursor.region() {
8449                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8450                        region.buffer_range.start
8451                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8452                                .min(region.buffer_range.end),
8453                    );
8454                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8455                    self.excerpt_bytes = Some(excerpt_bytes);
8456                    self.has_trailing_newline =
8457                        region.has_trailing_newline && self.range.end >= region.range.end;
8458                    if self.chunk.is_empty() && self.has_trailing_newline {
8459                        self.has_trailing_newline = false;
8460                        self.chunk = b"\n";
8461                    }
8462                }
8463            }
8464        }
8465    }
8466}
8467
8468impl<'a> Iterator for MultiBufferBytes<'a> {
8469    type Item = &'a [u8];
8470
8471    fn next(&mut self) -> Option<Self::Item> {
8472        let chunk = self.chunk;
8473        if chunk.is_empty() {
8474            None
8475        } else {
8476            self.consume(chunk.len());
8477            Some(chunk)
8478        }
8479    }
8480}
8481
8482impl io::Read for MultiBufferBytes<'_> {
8483    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8484        let len = cmp::min(buf.len(), self.chunk.len());
8485        buf[..len].copy_from_slice(&self.chunk[..len]);
8486        if len > 0 {
8487            self.consume(len);
8488        }
8489        Ok(len)
8490    }
8491}
8492
8493impl io::Read for ReversedMultiBufferBytes<'_> {
8494    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8495        let len = cmp::min(buf.len(), self.chunk.len());
8496        buf[..len].copy_from_slice(&self.chunk[..len]);
8497        buf[..len].reverse();
8498        if len > 0 {
8499            self.range.end -= len;
8500            self.chunk = &self.chunk[..self.chunk.len() - len];
8501            if !self.range.is_empty()
8502                && self.chunk.is_empty()
8503                && let Some(chunk) = self.chunks.next()
8504            {
8505                self.chunk = chunk.as_bytes();
8506            }
8507        }
8508        Ok(len)
8509    }
8510}
8511
8512impl<'a> Iterator for ExcerptChunks<'a> {
8513    type Item = Chunk<'a>;
8514
8515    fn next(&mut self) -> Option<Self::Item> {
8516        if let Some(chunk) = self.content_chunks.next() {
8517            return Some(chunk);
8518        }
8519
8520        if self.has_footer {
8521            let text = "\n";
8522            let chars = 0b1;
8523            self.has_footer = false;
8524            return Some(Chunk {
8525                text,
8526                chars,
8527                ..Default::default()
8528            });
8529        }
8530
8531        None
8532    }
8533}
8534
8535impl ToOffset for Point {
8536    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8537        snapshot.point_to_offset(*self)
8538    }
8539    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8540        snapshot.point_to_offset_utf16(*self)
8541    }
8542}
8543
8544impl ToOffset for MultiBufferOffset {
8545    #[track_caller]
8546    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8547        assert!(
8548            *self <= snapshot.len(),
8549            "offset {} is greater than the snapshot.len() {}",
8550            self.0,
8551            snapshot.len().0,
8552        );
8553        *self
8554    }
8555    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8556        snapshot.offset_to_offset_utf16(*self)
8557    }
8558}
8559
8560impl ToOffset for MultiBufferOffsetUtf16 {
8561    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8562        snapshot.offset_utf16_to_offset(*self)
8563    }
8564
8565    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8566        *self
8567    }
8568}
8569
8570impl ToOffset for PointUtf16 {
8571    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8572        snapshot.point_utf16_to_offset(*self)
8573    }
8574    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8575        snapshot.point_utf16_to_offset_utf16(*self)
8576    }
8577}
8578
8579impl ToPoint for MultiBufferOffset {
8580    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8581        snapshot.offset_to_point(*self)
8582    }
8583    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8584        snapshot.offset_to_point_utf16(*self)
8585    }
8586}
8587
8588impl ToPoint for Point {
8589    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8590        *self
8591    }
8592    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8593        snapshot.point_to_point_utf16(*self)
8594    }
8595}
8596
8597impl ToPoint for PointUtf16 {
8598    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8599        snapshot.point_utf16_to_point(*self)
8600    }
8601    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8602        *self
8603    }
8604}
8605
8606impl From<ExcerptId> for EntityId {
8607    fn from(id: ExcerptId) -> Self {
8608        EntityId::from(id.0 as u64)
8609    }
8610}
8611
8612#[cfg(debug_assertions)]
8613pub mod debug {
8614    use super::*;
8615
8616    pub trait ToMultiBufferDebugRanges {
8617        fn to_multi_buffer_debug_ranges(
8618            &self,
8619            snapshot: &MultiBufferSnapshot,
8620        ) -> Vec<Range<MultiBufferOffset>>;
8621    }
8622
8623    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8624        fn to_multi_buffer_debug_ranges(
8625            &self,
8626            snapshot: &MultiBufferSnapshot,
8627        ) -> Vec<Range<MultiBufferOffset>> {
8628            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8629        }
8630    }
8631
8632    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8633        fn to_multi_buffer_debug_ranges(
8634            &self,
8635            snapshot: &MultiBufferSnapshot,
8636        ) -> Vec<Range<MultiBufferOffset>> {
8637            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8638                .to_multi_buffer_debug_ranges(snapshot)
8639        }
8640    }
8641
8642    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8643        fn to_multi_buffer_debug_ranges(
8644            &self,
8645            snapshot: &MultiBufferSnapshot,
8646        ) -> Vec<Range<MultiBufferOffset>> {
8647            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8648        }
8649    }
8650
8651    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8652        fn to_multi_buffer_debug_ranges(
8653            &self,
8654            snapshot: &MultiBufferSnapshot,
8655        ) -> Vec<Range<MultiBufferOffset>> {
8656            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8657        }
8658    }
8659
8660    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8661        fn to_multi_buffer_debug_ranges(
8662            &self,
8663            snapshot: &MultiBufferSnapshot,
8664        ) -> Vec<Range<MultiBufferOffset>> {
8665            self.iter()
8666                .map(|item| {
8667                    let offset = item.to_offset(snapshot);
8668                    offset..offset
8669                })
8670                .collect()
8671        }
8672    }
8673
8674    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8675        fn to_multi_buffer_debug_ranges(
8676            &self,
8677            snapshot: &MultiBufferSnapshot,
8678        ) -> Vec<Range<MultiBufferOffset>> {
8679            self.iter()
8680                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8681                .collect()
8682        }
8683    }
8684}