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, DiffHunk,
  14    DiffHunkSecondaryStatus, 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    count: usize,
 803}
 804
 805#[derive(Debug, Clone)]
 806pub struct DiffTransformSummary {
 807    input: MBTextSummary,
 808    output: MBTextSummary,
 809}
 810
 811/// Summary of a string of text.
 812#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 813pub struct MBTextSummary {
 814    /// Length in bytes.
 815    pub len: MultiBufferOffset,
 816    /// Length in UTF-8.
 817    pub chars: usize,
 818    /// Length in UTF-16 code units
 819    pub len_utf16: OffsetUtf16,
 820    /// A point representing the number of lines and the length of the last line.
 821    ///
 822    /// In other words, it marks the point after the last byte in the text, (if
 823    /// EOF was a character, this would be its position).
 824    pub lines: Point,
 825    /// How many `char`s are in the first line
 826    pub first_line_chars: u32,
 827    /// How many `char`s are in the last line
 828    pub last_line_chars: u32,
 829    /// How many UTF-16 code units are in the last line
 830    pub last_line_len_utf16: u32,
 831    /// The row idx of the longest row
 832    pub longest_row: u32,
 833    /// How many `char`s are in the longest row
 834    pub longest_row_chars: u32,
 835}
 836
 837impl From<TextSummary> for MBTextSummary {
 838    fn from(summary: TextSummary) -> Self {
 839        MBTextSummary {
 840            len: MultiBufferOffset(summary.len),
 841            chars: summary.chars,
 842            len_utf16: summary.len_utf16,
 843            lines: summary.lines,
 844            first_line_chars: summary.first_line_chars,
 845            last_line_chars: summary.last_line_chars,
 846            last_line_len_utf16: summary.last_line_len_utf16,
 847            longest_row: summary.longest_row,
 848            longest_row_chars: summary.longest_row_chars,
 849        }
 850    }
 851}
 852
 853impl From<MBTextSummary> for TextSummary {
 854    fn from(summary: MBTextSummary) -> Self {
 855        TextSummary {
 856            len: summary.len.0,
 857            chars: summary.chars,
 858            len_utf16: summary.len_utf16,
 859            lines: summary.lines,
 860            first_line_chars: summary.first_line_chars,
 861            last_line_chars: summary.last_line_chars,
 862            last_line_len_utf16: summary.last_line_len_utf16,
 863            longest_row: summary.longest_row,
 864            longest_row_chars: summary.longest_row_chars,
 865        }
 866    }
 867}
 868
 869impl From<&str> for MBTextSummary {
 870    fn from(text: &str) -> Self {
 871        MBTextSummary::from(TextSummary::from(text))
 872    }
 873}
 874
 875impl MultiBufferDimension for MBTextSummary {
 876    type TextDimension = TextSummary;
 877
 878    fn from_summary(summary: &MBTextSummary) -> Self {
 879        *summary
 880    }
 881
 882    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 883        *self += *summary;
 884    }
 885
 886    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 887        *self += *summary;
 888    }
 889}
 890
 891impl AddAssign for MBTextSummary {
 892    fn add_assign(&mut self, other: MBTextSummary) {
 893        let joined_chars = self.last_line_chars + other.first_line_chars;
 894        if joined_chars > self.longest_row_chars {
 895            self.longest_row = self.lines.row;
 896            self.longest_row_chars = joined_chars;
 897        }
 898        if other.longest_row_chars > self.longest_row_chars {
 899            self.longest_row = self.lines.row + other.longest_row;
 900            self.longest_row_chars = other.longest_row_chars;
 901        }
 902
 903        if self.lines.row == 0 {
 904            self.first_line_chars += other.first_line_chars;
 905        }
 906
 907        if other.lines.row == 0 {
 908            self.last_line_chars += other.first_line_chars;
 909            self.last_line_len_utf16 += other.last_line_len_utf16;
 910        } else {
 911            self.last_line_chars = other.last_line_chars;
 912            self.last_line_len_utf16 = other.last_line_len_utf16;
 913        }
 914
 915        self.chars += other.chars;
 916        self.len += other.len;
 917        self.len_utf16 += other.len_utf16;
 918        self.lines += other.lines;
 919    }
 920}
 921
 922impl AddAssign<TextSummary> for MBTextSummary {
 923    fn add_assign(&mut self, other: TextSummary) {
 924        *self += MBTextSummary::from(other);
 925    }
 926}
 927
 928impl MBTextSummary {
 929    pub fn lines_utf16(&self) -> PointUtf16 {
 930        PointUtf16 {
 931            row: self.lines.row,
 932            column: self.last_line_len_utf16,
 933        }
 934    }
 935}
 936
 937impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 938where
 939    K: MultiBufferDimension,
 940    V: MultiBufferDimension,
 941{
 942    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 943
 944    fn from_summary(summary: &MBTextSummary) -> Self {
 945        Self {
 946            key: K::from_summary(summary),
 947            value: Some(V::from_summary(summary)),
 948        }
 949    }
 950
 951    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 952        self.key.add_text_dim(&summary.key);
 953        if let Some(value) = &mut self.value {
 954            if let Some(other_value) = summary.value.as_ref() {
 955                value.add_text_dim(other_value);
 956            }
 957        }
 958    }
 959
 960    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 961        self.key.add_mb_text_summary(summary);
 962        if let Some(value) = &mut self.value {
 963            value.add_mb_text_summary(summary);
 964        }
 965    }
 966}
 967
 968#[derive(Clone)]
 969pub struct MultiBufferRows<'a> {
 970    point: Point,
 971    is_empty: bool,
 972    is_singleton: bool,
 973    cursor: MultiBufferCursor<'a, Point, Point>,
 974}
 975
 976pub struct MultiBufferChunks<'a> {
 977    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 978    diff_transforms:
 979        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 980    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 981    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 982    buffer_chunk: Option<Chunk<'a>>,
 983    range: Range<MultiBufferOffset>,
 984    excerpt_offset_range: Range<ExcerptOffset>,
 985    excerpt_chunks: Option<ExcerptChunks<'a>>,
 986    language_aware: bool,
 987}
 988
 989pub struct ReversedMultiBufferChunks<'a> {
 990    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 991    current_chunks: Option<rope::Chunks<'a>>,
 992    start: MultiBufferOffset,
 993    offset: MultiBufferOffset,
 994}
 995
 996pub struct MultiBufferBytes<'a> {
 997    range: Range<MultiBufferOffset>,
 998    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 999    excerpt_bytes: Option<text::Bytes<'a>>,
1000    has_trailing_newline: bool,
1001    chunk: &'a [u8],
1002}
1003
1004pub struct ReversedMultiBufferBytes<'a> {
1005    range: Range<MultiBufferOffset>,
1006    chunks: ReversedMultiBufferChunks<'a>,
1007    chunk: &'a [u8],
1008}
1009
1010#[derive(Clone)]
1011struct DiffTransforms<MBD> {
1012    output_dimension: OutputDimension<MBD>,
1013    excerpt_dimension: ExcerptDimension<MBD>,
1014}
1015
1016impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1017    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1018        Self {
1019            output_dimension: OutputDimension::zero(cx),
1020            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1021                cx,
1022            ),
1023        }
1024    }
1025
1026    fn add_summary(
1027        &mut self,
1028        summary: &'a DiffTransformSummary,
1029        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1030    ) {
1031        self.output_dimension.add_summary(summary, cx);
1032        self.excerpt_dimension.add_summary(summary, cx);
1033    }
1034}
1035
1036#[derive(Clone)]
1037struct MultiBufferCursor<'a, MBD, BD> {
1038    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1039    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1040    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1041    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1042}
1043
1044#[derive(Clone)]
1045struct MultiBufferRegion<'a, MBD, BD> {
1046    buffer: &'a BufferSnapshot,
1047    is_main_buffer: bool,
1048    diff_hunk_status: Option<DiffHunkStatus>,
1049    excerpt: &'a Excerpt,
1050    buffer_range: Range<BD>,
1051    range: Range<MBD>,
1052    has_trailing_newline: bool,
1053}
1054
1055struct ExcerptChunks<'a> {
1056    excerpt_id: ExcerptId,
1057    content_chunks: BufferChunks<'a>,
1058    has_footer: bool,
1059}
1060
1061#[derive(Debug)]
1062struct BufferEdit {
1063    range: Range<BufferOffset>,
1064    new_text: Arc<str>,
1065    is_insertion: bool,
1066    original_indent_column: Option<u32>,
1067    excerpt_id: ExcerptId,
1068}
1069
1070#[derive(Clone, Copy, Debug, PartialEq)]
1071enum DiffChangeKind {
1072    BufferEdited,
1073    DiffUpdated { base_changed: bool },
1074    ExpandOrCollapseHunks { expand: bool },
1075}
1076
1077#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1078pub enum ExpandExcerptDirection {
1079    Up,
1080    Down,
1081    UpAndDown,
1082}
1083
1084impl ExpandExcerptDirection {
1085    pub fn should_expand_up(&self) -> bool {
1086        match self {
1087            ExpandExcerptDirection::Up => true,
1088            ExpandExcerptDirection::Down => false,
1089            ExpandExcerptDirection::UpAndDown => true,
1090        }
1091    }
1092
1093    pub fn should_expand_down(&self) -> bool {
1094        match self {
1095            ExpandExcerptDirection::Up => false,
1096            ExpandExcerptDirection::Down => true,
1097            ExpandExcerptDirection::UpAndDown => true,
1098        }
1099    }
1100}
1101
1102#[derive(Clone, Debug, PartialEq)]
1103pub struct IndentGuide {
1104    pub buffer_id: BufferId,
1105    pub start_row: MultiBufferRow,
1106    pub end_row: MultiBufferRow,
1107    pub depth: u32,
1108    pub tab_size: u32,
1109    pub settings: IndentGuideSettings,
1110}
1111
1112impl IndentGuide {
1113    pub fn indent_level(&self) -> u32 {
1114        self.depth * self.tab_size
1115    }
1116}
1117
1118impl MultiBuffer {
1119    pub fn new(capability: Capability) -> Self {
1120        Self::new_(
1121            capability,
1122            MultiBufferSnapshot {
1123                show_headers: true,
1124                show_deleted_hunks: true,
1125                ..MultiBufferSnapshot::default()
1126            },
1127        )
1128    }
1129
1130    pub fn without_headers(capability: Capability) -> Self {
1131        Self::new_(
1132            capability,
1133            MultiBufferSnapshot {
1134                show_deleted_hunks: true,
1135                ..MultiBufferSnapshot::default()
1136            },
1137        )
1138    }
1139
1140    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1141        let mut this = Self::new_(
1142            buffer.read(cx).capability(),
1143            MultiBufferSnapshot {
1144                singleton: true,
1145                show_deleted_hunks: true,
1146                ..MultiBufferSnapshot::default()
1147            },
1148        );
1149        this.singleton = true;
1150        let buffer_id = buffer.read(cx).remote_id();
1151        this.push_excerpts(
1152            buffer,
1153            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1154                buffer_id,
1155            ))],
1156            cx,
1157        );
1158        this
1159    }
1160
1161    #[inline]
1162    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1163        Self {
1164            snapshot: RefCell::new(snapshot),
1165            buffers: Default::default(),
1166            diffs: HashMap::default(),
1167            subscriptions: Topic::default(),
1168            singleton: false,
1169            capability,
1170            title: None,
1171            excerpts_by_path: Default::default(),
1172            paths_by_excerpt: Default::default(),
1173            buffer_changed_since_sync: Default::default(),
1174            history: History::default(),
1175        }
1176    }
1177
1178    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1179        let mut buffers = BTreeMap::default();
1180        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1181        for (buffer_id, buffer_state) in self.buffers.iter() {
1182            buffer_state.buffer.update(new_cx, |buffer, _| {
1183                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1184            });
1185            buffers.insert(
1186                *buffer_id,
1187                BufferState {
1188                    buffer: buffer_state.buffer.clone(),
1189                    last_version: buffer_state.last_version.clone(),
1190                    last_non_text_state_update_count: buffer_state
1191                        .last_non_text_state_update_count
1192                        .clone(),
1193                    excerpts: buffer_state.excerpts.clone(),
1194                    _subscriptions: [
1195                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1196                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1197                    ],
1198                },
1199            );
1200        }
1201        let mut diff_bases = HashMap::default();
1202        for (buffer_id, diff) in self.diffs.iter() {
1203            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1204        }
1205        Self {
1206            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1207            buffers,
1208            excerpts_by_path: Default::default(),
1209            paths_by_excerpt: Default::default(),
1210            diffs: diff_bases,
1211            subscriptions: Default::default(),
1212            singleton: self.singleton,
1213            capability: self.capability,
1214            history: self.history.clone(),
1215            title: self.title.clone(),
1216            buffer_changed_since_sync,
1217        }
1218    }
1219
1220    pub fn set_group_interval(&mut self, group_interval: Duration) {
1221        self.history.set_group_interval(group_interval);
1222    }
1223
1224    pub fn with_title(mut self, title: String) -> Self {
1225        self.title = Some(title);
1226        self
1227    }
1228
1229    pub fn read_only(&self) -> bool {
1230        !self.capability.editable()
1231    }
1232
1233    pub fn capability(&self) -> Capability {
1234        self.capability
1235    }
1236
1237    /// Returns an up-to-date snapshot of the MultiBuffer.
1238    #[ztracing::instrument(skip_all)]
1239    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1240        self.sync(cx);
1241        self.snapshot.borrow().clone()
1242    }
1243
1244    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1245        self.sync(cx);
1246        self.snapshot.borrow()
1247    }
1248
1249    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1250        if self.singleton {
1251            Some(self.buffers.values().next().unwrap().buffer.clone())
1252        } else {
1253            None
1254        }
1255    }
1256
1257    pub fn is_singleton(&self) -> bool {
1258        self.singleton
1259    }
1260
1261    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1262        self.subscriptions.subscribe()
1263    }
1264
1265    pub fn is_dirty(&self, cx: &App) -> bool {
1266        self.read(cx).is_dirty()
1267    }
1268
1269    pub fn has_deleted_file(&self, cx: &App) -> bool {
1270        self.read(cx).has_deleted_file()
1271    }
1272
1273    pub fn has_conflict(&self, cx: &App) -> bool {
1274        self.read(cx).has_conflict()
1275    }
1276
1277    // The `is_empty` signature doesn't match what clippy expects
1278    #[allow(clippy::len_without_is_empty)]
1279    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1280        self.read(cx).len()
1281    }
1282
1283    pub fn is_empty(&self) -> bool {
1284        self.buffers.is_empty()
1285    }
1286
1287    pub fn edit<I, S, T>(
1288        &mut self,
1289        edits: I,
1290        autoindent_mode: Option<AutoindentMode>,
1291        cx: &mut Context<Self>,
1292    ) where
1293        I: IntoIterator<Item = (Range<S>, T)>,
1294        S: ToOffset,
1295        T: Into<Arc<str>>,
1296    {
1297        self.edit_internal(edits, autoindent_mode, true, cx);
1298    }
1299
1300    pub fn edit_non_coalesce<I, S, T>(
1301        &mut self,
1302        edits: I,
1303        autoindent_mode: Option<AutoindentMode>,
1304        cx: &mut Context<Self>,
1305    ) where
1306        I: IntoIterator<Item = (Range<S>, T)>,
1307        S: ToOffset,
1308        T: Into<Arc<str>>,
1309    {
1310        self.edit_internal(edits, autoindent_mode, false, cx);
1311    }
1312
1313    fn edit_internal<I, S, T>(
1314        &mut self,
1315        edits: I,
1316        autoindent_mode: Option<AutoindentMode>,
1317        coalesce_adjacent: bool,
1318        cx: &mut Context<Self>,
1319    ) where
1320        I: IntoIterator<Item = (Range<S>, T)>,
1321        S: ToOffset,
1322        T: Into<Arc<str>>,
1323    {
1324        if self.read_only() || self.buffers.is_empty() {
1325            return;
1326        }
1327        self.sync_mut(cx);
1328        let edits = edits
1329            .into_iter()
1330            .map(|(range, new_text)| {
1331                let mut range = range.start.to_offset(self.snapshot.get_mut())
1332                    ..range.end.to_offset(self.snapshot.get_mut());
1333                if range.start > range.end {
1334                    mem::swap(&mut range.start, &mut range.end);
1335                }
1336                (range, new_text.into())
1337            })
1338            .collect::<Vec<_>>();
1339
1340        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1341
1342        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1343        fn edit_internal(
1344            this: &mut MultiBuffer,
1345            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1346            mut autoindent_mode: Option<AutoindentMode>,
1347            coalesce_adjacent: bool,
1348            cx: &mut Context<MultiBuffer>,
1349        ) {
1350            let original_indent_columns = match &mut autoindent_mode {
1351                Some(AutoindentMode::Block {
1352                    original_indent_columns,
1353                }) => mem::take(original_indent_columns),
1354                _ => Default::default(),
1355            };
1356
1357            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1358                edits,
1359                this.snapshot.get_mut(),
1360                &original_indent_columns,
1361            );
1362
1363            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1364            for (buffer_id, mut edits) in buffer_edits {
1365                buffer_ids.push(buffer_id);
1366                edits.sort_by_key(|edit| edit.range.start);
1367                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1368                    let mut edits = edits.into_iter().peekable();
1369                    let mut insertions = Vec::new();
1370                    let mut original_indent_columns = Vec::new();
1371                    let mut deletions = Vec::new();
1372                    let empty_str: Arc<str> = Arc::default();
1373                    while let Some(BufferEdit {
1374                        mut range,
1375                        mut new_text,
1376                        mut is_insertion,
1377                        original_indent_column,
1378                        excerpt_id,
1379                    }) = edits.next()
1380                    {
1381                        while let Some(BufferEdit {
1382                            range: next_range,
1383                            is_insertion: next_is_insertion,
1384                            new_text: next_new_text,
1385                            excerpt_id: next_excerpt_id,
1386                            ..
1387                        }) = edits.peek()
1388                        {
1389                            let should_coalesce = if coalesce_adjacent {
1390                                range.end >= next_range.start
1391                            } else {
1392                                range.end > next_range.start
1393                            };
1394
1395                            if should_coalesce {
1396                                range.end = cmp::max(next_range.end, range.end);
1397                                is_insertion |= *next_is_insertion;
1398                                if excerpt_id == *next_excerpt_id {
1399                                    new_text = format!("{new_text}{next_new_text}").into();
1400                                }
1401                                edits.next();
1402                            } else {
1403                                break;
1404                            }
1405                        }
1406
1407                        if is_insertion {
1408                            original_indent_columns.push(original_indent_column);
1409                            insertions.push((
1410                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1411                                new_text.clone(),
1412                            ));
1413                        } else if !range.is_empty() {
1414                            deletions.push((
1415                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1416                                empty_str.clone(),
1417                            ));
1418                        }
1419                    }
1420
1421                    let deletion_autoindent_mode =
1422                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1423                            Some(AutoindentMode::Block {
1424                                original_indent_columns: Default::default(),
1425                            })
1426                        } else {
1427                            autoindent_mode.clone()
1428                        };
1429                    let insertion_autoindent_mode =
1430                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1431                            Some(AutoindentMode::Block {
1432                                original_indent_columns,
1433                            })
1434                        } else {
1435                            autoindent_mode.clone()
1436                        };
1437
1438                    if coalesce_adjacent {
1439                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1440                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1441                    } else {
1442                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1443                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1444                    }
1445                })
1446            }
1447
1448            cx.emit(Event::ExcerptsEdited {
1449                excerpt_ids: edited_excerpt_ids,
1450                buffer_ids,
1451            });
1452        }
1453    }
1454
1455    fn convert_edits_to_buffer_edits(
1456        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1457        snapshot: &MultiBufferSnapshot,
1458        original_indent_columns: &[Option<u32>],
1459    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1460        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1461        let mut edited_excerpt_ids = Vec::new();
1462        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1463        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1464            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1465
1466            cursor.seek(&range.start);
1467            let mut start_region = cursor.region().expect("start offset out of bounds");
1468            if !start_region.is_main_buffer {
1469                cursor.next();
1470                if let Some(region) = cursor.region() {
1471                    start_region = region;
1472                } else {
1473                    continue;
1474                }
1475            }
1476
1477            if range.end < start_region.range.start {
1478                continue;
1479            }
1480
1481            let start_region = start_region.clone();
1482            if range.end > start_region.range.end {
1483                cursor.seek_forward(&range.end);
1484            }
1485            let mut end_region = cursor.region().expect("end offset out of bounds");
1486            if !end_region.is_main_buffer {
1487                cursor.prev();
1488                if let Some(region) = cursor.region() {
1489                    end_region = region;
1490                } else {
1491                    continue;
1492                }
1493            }
1494
1495            if range.start > end_region.range.end {
1496                continue;
1497            }
1498
1499            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1500            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1501            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1502                .min(start_region.buffer_range.end);
1503            let buffer_end =
1504                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1505
1506            if start_region.excerpt.id == end_region.excerpt.id {
1507                if start_region.buffer.capability == Capability::ReadWrite
1508                    && start_region.is_main_buffer
1509                {
1510                    edited_excerpt_ids.push(start_region.excerpt.id);
1511                    buffer_edits
1512                        .entry(start_region.buffer.remote_id())
1513                        .or_default()
1514                        .push(BufferEdit {
1515                            range: buffer_start..buffer_end,
1516                            new_text,
1517                            is_insertion: true,
1518                            original_indent_column,
1519                            excerpt_id: start_region.excerpt.id,
1520                        });
1521                }
1522            } else {
1523                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1524                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1525                if start_region.buffer.capability == Capability::ReadWrite
1526                    && start_region.is_main_buffer
1527                {
1528                    edited_excerpt_ids.push(start_region.excerpt.id);
1529                    buffer_edits
1530                        .entry(start_region.buffer.remote_id())
1531                        .or_default()
1532                        .push(BufferEdit {
1533                            range: start_excerpt_range,
1534                            new_text: new_text.clone(),
1535                            is_insertion: true,
1536                            original_indent_column,
1537                            excerpt_id: start_region.excerpt.id,
1538                        });
1539                }
1540                let excerpt_id = end_region.excerpt.id;
1541                if end_region.buffer.capability == Capability::ReadWrite
1542                    && end_region.is_main_buffer
1543                {
1544                    edited_excerpt_ids.push(excerpt_id);
1545                    buffer_edits
1546                        .entry(end_region.buffer.remote_id())
1547                        .or_default()
1548                        .push(BufferEdit {
1549                            range: end_excerpt_range,
1550                            new_text: new_text.clone(),
1551                            is_insertion: false,
1552                            original_indent_column,
1553                            excerpt_id,
1554                        });
1555                }
1556
1557                cursor.seek(&range.start);
1558                cursor.next_excerpt();
1559                while let Some(region) = cursor.region() {
1560                    if region.excerpt.id == excerpt_id {
1561                        break;
1562                    }
1563                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1564                        edited_excerpt_ids.push(region.excerpt.id);
1565                        buffer_edits
1566                            .entry(region.buffer.remote_id())
1567                            .or_default()
1568                            .push(BufferEdit {
1569                                range: region.buffer_range.clone(),
1570                                new_text: new_text.clone(),
1571                                is_insertion: false,
1572                                original_indent_column,
1573                                excerpt_id: region.excerpt.id,
1574                            });
1575                    }
1576                    cursor.next_excerpt();
1577                }
1578            }
1579        }
1580        (buffer_edits, edited_excerpt_ids)
1581    }
1582
1583    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1584    where
1585        I: IntoIterator<Item = Range<S>>,
1586        S: ToOffset,
1587    {
1588        if self.read_only() || self.buffers.is_empty() {
1589            return;
1590        }
1591        self.sync_mut(cx);
1592        let empty = Arc::<str>::from("");
1593        let edits = ranges
1594            .into_iter()
1595            .map(|range| {
1596                let mut range = range.start.to_offset(self.snapshot.get_mut())
1597                    ..range.end.to_offset(&self.snapshot.get_mut());
1598                if range.start > range.end {
1599                    mem::swap(&mut range.start, &mut range.end);
1600                }
1601                (range, empty.clone())
1602            })
1603            .collect::<Vec<_>>();
1604
1605        return autoindent_ranges_internal(self, edits, cx);
1606
1607        fn autoindent_ranges_internal(
1608            this: &mut MultiBuffer,
1609            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1610            cx: &mut Context<MultiBuffer>,
1611        ) {
1612            let (buffer_edits, edited_excerpt_ids) =
1613                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1614
1615            let mut buffer_ids = Vec::new();
1616            for (buffer_id, mut edits) in buffer_edits {
1617                buffer_ids.push(buffer_id);
1618                edits.sort_unstable_by_key(|edit| edit.range.start);
1619
1620                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1621                for edit in edits {
1622                    if let Some(last_range) = ranges.last_mut()
1623                        && edit.range.start <= last_range.end
1624                    {
1625                        last_range.end = last_range.end.max(edit.range.end);
1626                        continue;
1627                    }
1628                    ranges.push(edit.range);
1629                }
1630
1631                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1632                    buffer.autoindent_ranges(ranges, cx);
1633                })
1634            }
1635
1636            cx.emit(Event::ExcerptsEdited {
1637                excerpt_ids: edited_excerpt_ids,
1638                buffer_ids,
1639            });
1640        }
1641    }
1642
1643    pub fn set_active_selections(
1644        &self,
1645        selections: &[Selection<Anchor>],
1646        line_mode: bool,
1647        cursor_shape: CursorShape,
1648        cx: &mut Context<Self>,
1649    ) {
1650        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1651            Default::default();
1652        let snapshot = self.read(cx);
1653        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1654        for selection in selections {
1655            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1656            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1657
1658            cursor.seek(&Some(start_locator), Bias::Left);
1659            while let Some(excerpt) = cursor.item()
1660                && excerpt.locator <= *end_locator
1661            {
1662                let mut start = excerpt.range.context.start;
1663                let mut end = excerpt.range.context.end;
1664                if excerpt.id == selection.start.excerpt_id {
1665                    start = selection.start.text_anchor;
1666                }
1667                if excerpt.id == selection.end.excerpt_id {
1668                    end = selection.end.text_anchor;
1669                }
1670                selections_by_buffer
1671                    .entry(excerpt.buffer_id)
1672                    .or_default()
1673                    .push(Selection {
1674                        id: selection.id,
1675                        start,
1676                        end,
1677                        reversed: selection.reversed,
1678                        goal: selection.goal,
1679                    });
1680
1681                cursor.next();
1682            }
1683        }
1684
1685        for (buffer_id, buffer_state) in self.buffers.iter() {
1686            if !selections_by_buffer.contains_key(buffer_id) {
1687                buffer_state
1688                    .buffer
1689                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1690            }
1691        }
1692
1693        for (buffer_id, mut selections) in selections_by_buffer {
1694            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1695                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1696                let mut selections = selections.into_iter().peekable();
1697                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1698                    let mut selection = selections.next()?;
1699                    while let Some(next_selection) = selections.peek() {
1700                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1701                            let next_selection = selections.next().unwrap();
1702                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1703                                selection.end = next_selection.end;
1704                            }
1705                        } else {
1706                            break;
1707                        }
1708                    }
1709                    Some(selection)
1710                }));
1711                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1712            });
1713        }
1714    }
1715
1716    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1717        for buffer in self.buffers.values() {
1718            buffer
1719                .buffer
1720                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1721        }
1722    }
1723
1724    pub fn push_excerpts<O>(
1725        &mut self,
1726        buffer: Entity<Buffer>,
1727        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1728        cx: &mut Context<Self>,
1729    ) -> Vec<ExcerptId>
1730    where
1731        O: text::ToOffset,
1732    {
1733        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1734    }
1735
1736    #[instrument(skip_all)]
1737    fn merge_excerpt_ranges<'a>(
1738        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1739    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1740        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1741        let mut counts: Vec<usize> = Vec::new();
1742        for range in expanded_ranges {
1743            if let Some(last_range) = merged_ranges.last_mut() {
1744                assert!(
1745                    last_range.context.start <= range.context.start,
1746                    "ranges must be sorted: {last_range:?} <= {range:?}"
1747                );
1748                if last_range.context.end >= range.context.start
1749                    || last_range.context.end.row + 1 == range.context.start.row
1750                {
1751                    last_range.context.end = range.context.end.max(last_range.context.end);
1752                    *counts.last_mut().unwrap() += 1;
1753                    continue;
1754                }
1755            }
1756            merged_ranges.push(range.clone());
1757            counts.push(1);
1758        }
1759        (merged_ranges, counts)
1760    }
1761
1762    pub fn insert_excerpts_after<O>(
1763        &mut self,
1764        prev_excerpt_id: ExcerptId,
1765        buffer: Entity<Buffer>,
1766        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1767        cx: &mut Context<Self>,
1768    ) -> Vec<ExcerptId>
1769    where
1770        O: text::ToOffset,
1771    {
1772        let mut ids = Vec::new();
1773        let mut next_excerpt_id =
1774            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1775                last_entry.id.0 + 1
1776            } else {
1777                1
1778            };
1779        self.insert_excerpts_with_ids_after(
1780            prev_excerpt_id,
1781            buffer,
1782            ranges.into_iter().map(|range| {
1783                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1784                ids.push(id);
1785                (id, range)
1786            }),
1787            cx,
1788        );
1789        ids
1790    }
1791
1792    pub fn insert_excerpts_with_ids_after<O>(
1793        &mut self,
1794        prev_excerpt_id: ExcerptId,
1795        buffer: Entity<Buffer>,
1796        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1797        cx: &mut Context<Self>,
1798    ) where
1799        O: text::ToOffset,
1800    {
1801        assert_eq!(self.history.transaction_depth(), 0);
1802        let mut ranges = ranges.into_iter().peekable();
1803        if ranges.peek().is_none() {
1804            return Default::default();
1805        }
1806
1807        self.sync_mut(cx);
1808
1809        let buffer_snapshot = buffer.read(cx).snapshot();
1810        let buffer_id = buffer_snapshot.remote_id();
1811
1812        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1813            self.buffer_changed_since_sync.replace(true);
1814            buffer.update(cx, |buffer, _| {
1815                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1816            });
1817            BufferState {
1818                last_version: RefCell::new(buffer_snapshot.version().clone()),
1819                last_non_text_state_update_count: Cell::new(
1820                    buffer_snapshot.non_text_state_update_count(),
1821                ),
1822                excerpts: Default::default(),
1823                _subscriptions: [
1824                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1825                    cx.subscribe(&buffer, Self::on_buffer_event),
1826                ],
1827                buffer: buffer.clone(),
1828            }
1829        });
1830
1831        let mut snapshot = self.snapshot.get_mut();
1832
1833        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1834        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1835        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1836        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1837        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1838
1839        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1840        new_excerpts.update_last(
1841            |excerpt| {
1842                excerpt.has_trailing_newline = true;
1843            },
1844            (),
1845        );
1846
1847        let next_locator = if let Some(excerpt) = cursor.item() {
1848            excerpt.locator.clone()
1849        } else {
1850            Locator::max()
1851        };
1852
1853        let mut excerpts = Vec::new();
1854        let buffer_snapshot = Arc::new(buffer_snapshot);
1855        while let Some((id, range)) = ranges.next() {
1856            let locator = Locator::between(&prev_locator, &next_locator);
1857            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1858                buffer_state.excerpts.insert(ix, locator.clone());
1859            }
1860            let range = ExcerptRange {
1861                context: buffer_snapshot.anchor_before(&range.context.start)
1862                    ..buffer_snapshot.anchor_after(&range.context.end),
1863                primary: buffer_snapshot.anchor_before(&range.primary.start)
1864                    ..buffer_snapshot.anchor_after(&range.primary.end),
1865            };
1866            excerpts.push((id, range.clone()));
1867            let excerpt = Excerpt::new(
1868                id,
1869                locator.clone(),
1870                buffer_id,
1871                buffer_snapshot.clone(),
1872                range,
1873                ranges.peek().is_some() || cursor.item().is_some(),
1874            );
1875            new_excerpts.push(excerpt, ());
1876            prev_locator = locator.clone();
1877
1878            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1879                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1880            }
1881            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1882        }
1883        snapshot
1884            .buffer_locators
1885            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1886
1887        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1888
1889        let suffix = cursor.suffix();
1890        let changed_trailing_excerpt = suffix.is_empty();
1891        new_excerpts.append(suffix, ());
1892        drop(cursor);
1893        snapshot.excerpts = new_excerpts;
1894        snapshot.excerpt_ids = new_excerpt_ids;
1895        if changed_trailing_excerpt {
1896            snapshot.trailing_excerpt_update_count += 1;
1897        }
1898
1899        let edits = Self::sync_diff_transforms(
1900            &mut snapshot,
1901            vec![Edit {
1902                old: edit_start..edit_start,
1903                new: edit_start..edit_end,
1904            }],
1905            DiffChangeKind::BufferEdited,
1906        );
1907        if !edits.is_empty() {
1908            self.subscriptions.publish(edits);
1909        }
1910
1911        cx.emit(Event::Edited {
1912            edited_buffer: None,
1913        });
1914        cx.emit(Event::ExcerptsAdded {
1915            buffer,
1916            predecessor: prev_excerpt_id,
1917            excerpts,
1918        });
1919        cx.notify();
1920    }
1921
1922    pub fn clear(&mut self, cx: &mut Context<Self>) {
1923        self.sync_mut(cx);
1924        let ids = self.excerpt_ids();
1925        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1926        self.excerpts_by_path.clear();
1927        self.paths_by_excerpt.clear();
1928        let MultiBufferSnapshot {
1929            excerpts,
1930            buffer_locators,
1931            diffs: _,
1932            diff_transforms: _,
1933            non_text_state_update_count: _,
1934            edit_count: _,
1935            is_dirty,
1936            has_deleted_file,
1937            has_conflict,
1938            has_inverted_diff,
1939            singleton: _,
1940            excerpt_ids: _,
1941            replaced_excerpts,
1942            trailing_excerpt_update_count,
1943            all_diff_hunks_expanded: _,
1944            show_deleted_hunks: _,
1945            use_extended_diff_range: _,
1946            show_headers: _,
1947        } = self.snapshot.get_mut();
1948        buffer_locators.clear();
1949        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1950        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1951        *excerpts = Default::default();
1952        *trailing_excerpt_update_count += 1;
1953        *is_dirty = false;
1954        *has_deleted_file = false;
1955        *has_conflict = false;
1956        *has_inverted_diff = false;
1957        replaced_excerpts.clear();
1958
1959        let edits = Self::sync_diff_transforms(
1960            self.snapshot.get_mut(),
1961            vec![Edit {
1962                old: start..prev_len,
1963                new: start..start,
1964            }],
1965            DiffChangeKind::BufferEdited,
1966        );
1967        if !edits.is_empty() {
1968            self.subscriptions.publish(edits);
1969        }
1970        cx.emit(Event::Edited {
1971            edited_buffer: None,
1972        });
1973        cx.emit(Event::ExcerptsRemoved {
1974            ids,
1975            removed_buffer_ids,
1976        });
1977        cx.notify();
1978    }
1979
1980    #[ztracing::instrument(skip_all)]
1981    pub fn excerpts_for_buffer(
1982        &self,
1983        buffer_id: BufferId,
1984        cx: &App,
1985    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1986        let mut excerpts = Vec::new();
1987        let snapshot = self.read(cx);
1988        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1989        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1990            for locator in &**locators {
1991                cursor.seek_forward(&Some(locator), Bias::Left);
1992                if let Some(excerpt) = cursor.item()
1993                    && excerpt.locator == *locator
1994                {
1995                    excerpts.push((excerpt.id, excerpt.range.clone()));
1996                }
1997            }
1998        }
1999
2000        excerpts
2001    }
2002
2003    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2004        let snapshot = self.read(cx);
2005        let mut excerpts = snapshot
2006            .excerpts
2007            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2008        let mut diff_transforms = snapshot
2009            .diff_transforms
2010            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2011        diff_transforms.next();
2012        let locators = snapshot
2013            .buffer_locators
2014            .get(&buffer_id)
2015            .into_iter()
2016            .flat_map(|v| &**v);
2017        let mut result = Vec::new();
2018        for locator in locators {
2019            excerpts.seek_forward(&Some(locator), Bias::Left);
2020            if let Some(excerpt) = excerpts.item()
2021                && excerpt.locator == *locator
2022            {
2023                let excerpt_start = excerpts.start().1;
2024                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2025
2026                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2027                let overshoot = excerpt_start - diff_transforms.start().0;
2028                let start = diff_transforms.start().1 + overshoot;
2029
2030                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2031                let overshoot = excerpt_end - diff_transforms.start().0;
2032                let end = diff_transforms.start().1 + overshoot;
2033
2034                result.push(start.0..end.0)
2035            }
2036        }
2037        result
2038    }
2039
2040    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2041        self.snapshot
2042            .borrow()
2043            .excerpts
2044            .iter()
2045            .map(|entry| entry.buffer_id)
2046            .collect()
2047    }
2048
2049    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2050        let snapshot = self.snapshot.borrow();
2051        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2052        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2053        ids
2054    }
2055
2056    pub fn excerpt_containing(
2057        &self,
2058        position: impl ToOffset,
2059        cx: &App,
2060    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2061        let snapshot = self.read(cx);
2062        let offset = position.to_offset(&snapshot);
2063
2064        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2065        cursor.seek(&offset);
2066        cursor
2067            .excerpt()
2068            .or_else(|| snapshot.excerpts.last())
2069            .map(|excerpt| {
2070                (
2071                    excerpt.id,
2072                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2073                    excerpt.range.context.clone(),
2074                )
2075            })
2076    }
2077
2078    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2079        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2080            self.buffer(buffer_id)
2081        } else {
2082            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2083            Some(buffer)
2084        }
2085    }
2086
2087    // If point is at the end of the buffer, the last excerpt is returned
2088    pub fn point_to_buffer_offset<T: ToOffset>(
2089        &self,
2090        point: T,
2091        cx: &App,
2092    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2093        let snapshot = self.read(cx);
2094        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2095        Some((
2096            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2097            offset,
2098        ))
2099    }
2100
2101    // If point is at the end of the buffer, the last excerpt is returned
2102    pub fn point_to_buffer_point<T: ToPoint>(
2103        &self,
2104        point: T,
2105        cx: &App,
2106    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2107        let snapshot = self.read(cx);
2108        let (buffer, point, is_main_buffer) =
2109            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2110        Some((
2111            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2112            point,
2113            is_main_buffer,
2114        ))
2115    }
2116
2117    pub fn buffer_point_to_anchor(
2118        &self,
2119        // todo(lw): We shouldn't need this?
2120        buffer: &Entity<Buffer>,
2121        point: Point,
2122        cx: &App,
2123    ) -> Option<Anchor> {
2124        let mut found = None;
2125        let snapshot = buffer.read(cx).snapshot();
2126        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2127            let start = range.context.start.to_point(&snapshot);
2128            let end = range.context.end.to_point(&snapshot);
2129            if start <= point && point < end {
2130                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2131                break;
2132            }
2133            if point < start {
2134                found = Some((start, excerpt_id));
2135            }
2136            if point > end {
2137                found = Some((end, excerpt_id));
2138            }
2139        }
2140
2141        found.map(|(point, excerpt_id)| {
2142            let text_anchor = snapshot.anchor_after(point);
2143            Anchor::in_buffer(excerpt_id, text_anchor)
2144        })
2145    }
2146
2147    pub fn buffer_anchor_to_anchor(
2148        &self,
2149        // todo(lw): We shouldn't need this?
2150        buffer: &Entity<Buffer>,
2151        anchor: text::Anchor,
2152        cx: &App,
2153    ) -> Option<Anchor> {
2154        let snapshot = buffer.read(cx).snapshot();
2155        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2156            if range.context.start.cmp(&anchor, &snapshot).is_le()
2157                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2158            {
2159                return Some(Anchor::in_buffer(excerpt_id, anchor));
2160            }
2161        }
2162
2163        None
2164    }
2165
2166    pub fn merge_excerpts(
2167        &mut self,
2168        excerpt_ids: &[ExcerptId],
2169        cx: &mut Context<Self>,
2170    ) -> ExcerptId {
2171        debug_assert!(!excerpt_ids.is_empty());
2172        if excerpt_ids.len() == 1 {
2173            return excerpt_ids[0];
2174        }
2175
2176        let snapshot = self.snapshot(cx);
2177
2178        let first_range = snapshot
2179            .context_range_for_excerpt(excerpt_ids[0])
2180            .expect("first excerpt must exist");
2181        let last_range = snapshot
2182            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2183            .expect("last excerpt must exist");
2184
2185        let union_range = first_range.start..last_range.end;
2186
2187        drop(snapshot);
2188
2189        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2190        self.remove_excerpts(excerpt_ids[1..].iter().copied(), cx);
2191
2192        excerpt_ids[0]
2193    }
2194
2195    pub fn remove_excerpts(
2196        &mut self,
2197        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2198        cx: &mut Context<Self>,
2199    ) {
2200        self.sync_mut(cx);
2201        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2202        if ids.is_empty() {
2203            return;
2204        }
2205        self.buffer_changed_since_sync.replace(true);
2206
2207        let mut snapshot = self.snapshot.get_mut();
2208        let mut new_excerpts = SumTree::default();
2209        let mut cursor = snapshot
2210            .excerpts
2211            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2212        let mut edits = Vec::new();
2213        let mut excerpt_ids = ids.iter().copied().peekable();
2214        let mut removed_buffer_ids = Vec::new();
2215        let mut removed_excerpts_for_buffers = HashSet::default();
2216
2217        while let Some(excerpt_id) = excerpt_ids.next() {
2218            self.paths_by_excerpt.remove(&excerpt_id);
2219            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2220            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2221            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2222
2223            if let Some(mut excerpt) = cursor.item() {
2224                if excerpt.id != excerpt_id {
2225                    continue;
2226                }
2227                let mut old_start = cursor.start().1;
2228
2229                // Skip over the removed excerpt.
2230                'remove_excerpts: loop {
2231                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2232                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2233                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2234                        if buffer_state.excerpts.is_empty() {
2235                            log::debug!(
2236                                "removing buffer and diff for buffer {}",
2237                                excerpt.buffer_id
2238                            );
2239                            self.buffers.remove(&excerpt.buffer_id);
2240                            removed_buffer_ids.push(excerpt.buffer_id);
2241                        }
2242                    }
2243                    cursor.next();
2244
2245                    // Skip over any subsequent excerpts that are also removed.
2246                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2247                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2248                        if let Some(next_excerpt) = cursor.item()
2249                            && next_excerpt.locator == *next_locator
2250                        {
2251                            excerpt_ids.next();
2252                            excerpt = next_excerpt;
2253                            continue 'remove_excerpts;
2254                        }
2255                    }
2256
2257                    break;
2258                }
2259
2260                // When removing the last excerpt, remove the trailing newline from
2261                // the previous excerpt.
2262                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2263                    old_start -= 1;
2264                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2265                }
2266
2267                // Push an edit for the removal of this run of excerpts.
2268                let old_end = cursor.start().1;
2269                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2270                edits.push(Edit {
2271                    old: old_start..old_end,
2272                    new: new_start..new_start,
2273                });
2274            }
2275        }
2276        let suffix = cursor.suffix();
2277        let changed_trailing_excerpt = suffix.is_empty();
2278        new_excerpts.append(suffix, ());
2279        drop(cursor);
2280        for buffer_id in removed_excerpts_for_buffers {
2281            match self.buffers.get(&buffer_id) {
2282                Some(buffer_state) => {
2283                    snapshot
2284                        .buffer_locators
2285                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2286                }
2287                None => {
2288                    snapshot.buffer_locators.remove(&buffer_id);
2289                }
2290            }
2291        }
2292        snapshot.excerpts = new_excerpts;
2293        for buffer_id in &removed_buffer_ids {
2294            self.diffs.remove(buffer_id);
2295            snapshot.diffs.remove(buffer_id);
2296        }
2297
2298        // Recalculate has_inverted_diff after removing diffs
2299        if !removed_buffer_ids.is_empty() {
2300            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2301        }
2302
2303        if changed_trailing_excerpt {
2304            snapshot.trailing_excerpt_update_count += 1;
2305        }
2306
2307        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2308        if !edits.is_empty() {
2309            self.subscriptions.publish(edits);
2310        }
2311        cx.emit(Event::Edited {
2312            edited_buffer: None,
2313        });
2314        cx.emit(Event::ExcerptsRemoved {
2315            ids,
2316            removed_buffer_ids,
2317        });
2318        cx.notify();
2319    }
2320
2321    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2322        &self,
2323        anchors: Anchors,
2324        cx: &mut Context<Self>,
2325    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2326        let mut error = None;
2327        let mut futures = Vec::new();
2328        for anchor in anchors {
2329            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2330                if let Some(buffer) = self.buffers.get(&buffer_id) {
2331                    buffer.buffer.update(cx, |buffer, _| {
2332                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2333                    });
2334                } else {
2335                    error = Some(anyhow!(
2336                        "buffer {buffer_id} is not part of this multi-buffer"
2337                    ));
2338                    break;
2339                }
2340            }
2341        }
2342        async move {
2343            if let Some(error) = error {
2344                Err(error)?;
2345            }
2346            for future in futures {
2347                future.await?;
2348            }
2349            Ok(())
2350        }
2351    }
2352
2353    pub fn text_anchor_for_position<T: ToOffset>(
2354        &self,
2355        position: T,
2356        cx: &App,
2357    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2358        let snapshot = self.read(cx);
2359        let anchor = snapshot.anchor_before(position);
2360        let buffer = self
2361            .buffers
2362            .get(&anchor.text_anchor.buffer_id?)?
2363            .buffer
2364            .clone();
2365        Some((buffer, anchor.text_anchor))
2366    }
2367
2368    fn on_buffer_event(
2369        &mut self,
2370        buffer: Entity<Buffer>,
2371        event: &language::BufferEvent,
2372        cx: &mut Context<Self>,
2373    ) {
2374        use language::BufferEvent;
2375        let buffer_id = buffer.read(cx).remote_id();
2376        cx.emit(match event {
2377            BufferEvent::Edited => Event::Edited {
2378                edited_buffer: Some(buffer),
2379            },
2380            BufferEvent::DirtyChanged => Event::DirtyChanged,
2381            BufferEvent::Saved => Event::Saved,
2382            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2383            BufferEvent::Reloaded => Event::Reloaded,
2384            BufferEvent::LanguageChanged(has_language) => {
2385                Event::LanguageChanged(buffer_id, *has_language)
2386            }
2387            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2388            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2389            BufferEvent::CapabilityChanged => {
2390                self.capability = buffer.read(cx).capability();
2391                return;
2392            }
2393            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2394        });
2395    }
2396
2397    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2398        let diff = diff.read(cx);
2399        let buffer_id = diff.buffer_id;
2400        let diff = DiffStateSnapshot {
2401            diff: diff.snapshot(cx),
2402            is_inverted: false,
2403        };
2404        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2405    }
2406
2407    fn inverted_buffer_diff_language_changed(
2408        &mut self,
2409        diff: Entity<BufferDiff>,
2410        cx: &mut Context<Self>,
2411    ) {
2412        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2413        let diff = diff.read(cx);
2414        let diff = DiffStateSnapshot {
2415            diff: diff.snapshot(cx),
2416            is_inverted: true,
2417        };
2418        self.snapshot
2419            .get_mut()
2420            .diffs
2421            .insert(base_text_buffer_id, diff);
2422    }
2423
2424    fn buffer_diff_changed(
2425        &mut self,
2426        diff: Entity<BufferDiff>,
2427        range: Range<text::Anchor>,
2428        cx: &mut Context<Self>,
2429    ) {
2430        self.sync_mut(cx);
2431
2432        let diff = diff.read(cx);
2433        let buffer_id = diff.buffer_id;
2434
2435        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2436            return;
2437        };
2438        let new_diff = DiffStateSnapshot {
2439            diff: diff.snapshot(cx),
2440            is_inverted: false,
2441        };
2442        let mut snapshot = self.snapshot.get_mut();
2443        let base_text_changed = snapshot
2444            .diffs
2445            .get(&buffer_id)
2446            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2447        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2448
2449        let buffer = buffer_state.buffer.read(cx);
2450        let diff_change_range = range.to_offset(buffer);
2451
2452        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2453        let edits = Self::sync_diff_transforms(
2454            &mut snapshot,
2455            excerpt_edits,
2456            DiffChangeKind::DiffUpdated {
2457                base_changed: base_text_changed,
2458            },
2459        );
2460        if !edits.is_empty() {
2461            self.subscriptions.publish(edits);
2462        }
2463        cx.emit(Event::Edited {
2464            edited_buffer: None,
2465        });
2466    }
2467
2468    fn inverted_buffer_diff_changed(
2469        &mut self,
2470        diff: Entity<BufferDiff>,
2471        diff_change_range: Range<usize>,
2472        cx: &mut Context<Self>,
2473    ) {
2474        self.sync_mut(cx);
2475
2476        let diff = diff.read(cx);
2477        let base_text_buffer_id = diff.base_text(cx).remote_id();
2478        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2479            return;
2480        };
2481
2482        let new_diff = DiffStateSnapshot {
2483            diff: diff.snapshot(cx),
2484            is_inverted: true,
2485        };
2486        let mut snapshot = self.snapshot.get_mut();
2487        snapshot
2488            .diffs
2489            .insert_or_replace(base_text_buffer_id, new_diff);
2490
2491        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2492        let edits = Self::sync_diff_transforms(
2493            &mut snapshot,
2494            excerpt_edits,
2495            DiffChangeKind::DiffUpdated {
2496                // We don't read this field for inverted diffs.
2497                base_changed: false,
2498            },
2499        );
2500        if !edits.is_empty() {
2501            self.subscriptions.publish(edits);
2502        }
2503        cx.emit(Event::Edited {
2504            edited_buffer: None,
2505        });
2506    }
2507
2508    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2509        self.buffers.values().map(|state| state.buffer.clone())
2510    }
2511
2512    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2513        self.all_buffers_iter().collect()
2514    }
2515
2516    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2517        self.buffers.keys().copied()
2518    }
2519
2520    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2521        self.all_buffer_ids_iter().collect()
2522    }
2523
2524    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2525        self.buffers
2526            .get(&buffer_id)
2527            .map(|state| state.buffer.clone())
2528    }
2529
2530    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2531        self.point_to_buffer_offset(point, cx)
2532            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2533    }
2534
2535    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2536        let buffer_id = self
2537            .snapshot
2538            .borrow()
2539            .excerpts
2540            .first()
2541            .map(|excerpt| excerpt.buffer.remote_id());
2542        buffer_id
2543            .and_then(|buffer_id| self.buffer(buffer_id))
2544            .map(|buffer| {
2545                let buffer = buffer.read(cx);
2546                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2547            })
2548            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2549    }
2550
2551    pub fn language_settings_at<'a, T: ToOffset>(
2552        &'a self,
2553        point: T,
2554        cx: &'a App,
2555    ) -> Cow<'a, LanguageSettings> {
2556        let mut language = None;
2557        let mut file = None;
2558        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2559            let buffer = buffer.read(cx);
2560            language = buffer.language_at(offset);
2561            file = buffer.file();
2562        }
2563        language_settings(language.map(|l| l.name()), file, cx)
2564    }
2565
2566    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2567        self.buffers.values().for_each(|state| f(&state.buffer))
2568    }
2569
2570    pub fn explicit_title(&self) -> Option<&str> {
2571        self.title.as_deref()
2572    }
2573
2574    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2575        if let Some(title) = self.title.as_ref() {
2576            return title.into();
2577        }
2578
2579        if let Some(buffer) = self.as_singleton() {
2580            let buffer = buffer.read(cx);
2581
2582            if let Some(file) = buffer.file() {
2583                return file.file_name(cx).into();
2584            }
2585
2586            if let Some(title) = self.buffer_content_title(buffer) {
2587                return title;
2588            }
2589        };
2590
2591        "untitled".into()
2592    }
2593
2594    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2595        let mut is_leading_whitespace = true;
2596        let mut count = 0;
2597        let mut prev_was_space = false;
2598        let mut title = String::new();
2599
2600        for ch in buffer.snapshot().chars() {
2601            if is_leading_whitespace && ch.is_whitespace() {
2602                continue;
2603            }
2604
2605            is_leading_whitespace = false;
2606
2607            if ch == '\n' || count >= 40 {
2608                break;
2609            }
2610
2611            if ch.is_whitespace() {
2612                if !prev_was_space {
2613                    title.push(' ');
2614                    count += 1;
2615                    prev_was_space = true;
2616                }
2617            } else {
2618                title.push(ch);
2619                count += 1;
2620                prev_was_space = false;
2621            }
2622        }
2623
2624        let title = title.trim_end().to_string();
2625
2626        if title.is_empty() {
2627            return None;
2628        }
2629
2630        Some(title.into())
2631    }
2632
2633    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2634        self.title = Some(title);
2635        cx.notify();
2636    }
2637
2638    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2639    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2640        for buffer_state in self.buffers.values() {
2641            buffer_state
2642                .buffer
2643                .update(cx, |buffer, _cx| buffer.refresh_preview());
2644        }
2645    }
2646
2647    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2648    pub fn preserve_preview(&self, cx: &App) -> bool {
2649        self.buffers
2650            .values()
2651            .all(|state| state.buffer.read(cx).preserve_preview())
2652    }
2653
2654    #[cfg(any(test, feature = "test-support"))]
2655    pub fn is_parsing(&self, cx: &App) -> bool {
2656        self.as_singleton().unwrap().read(cx).is_parsing()
2657    }
2658
2659    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2660        let buffer_id = diff.read(cx).buffer_id;
2661
2662        if let Some(existing_diff) = self.diff_for(buffer_id)
2663            && diff.entity_id() == existing_diff.entity_id()
2664        {
2665            return;
2666        }
2667
2668        self.buffer_diff_changed(
2669            diff.clone(),
2670            text::Anchor::min_max_range_for_buffer(buffer_id),
2671            cx,
2672        );
2673        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2674    }
2675
2676    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2677        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2678        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2679        self.snapshot.get_mut().has_inverted_diff = true;
2680        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2681        self.diffs
2682            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2683    }
2684
2685    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2686        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2687    }
2688
2689    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2690        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2691    }
2692
2693    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2694        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2695    }
2696
2697    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2698        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2699        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2700    }
2701
2702    pub fn all_diff_hunks_expanded(&self) -> bool {
2703        self.snapshot.borrow().all_diff_hunks_expanded
2704    }
2705
2706    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2707        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2708        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2709    }
2710
2711    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2712        self.snapshot.get_mut().show_deleted_hunks = show;
2713
2714        self.sync_mut(cx);
2715
2716        let old_len = self.snapshot.borrow().len();
2717
2718        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2719        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2720
2721        let new_len = self.snapshot.borrow().len();
2722
2723        self.subscriptions.publish(vec![Edit {
2724            old: MultiBufferOffset(0)..old_len,
2725            new: MultiBufferOffset(0)..new_len,
2726        }]);
2727
2728        cx.emit(Event::DiffHunksToggled);
2729        cx.emit(Event::Edited {
2730            edited_buffer: None,
2731        });
2732    }
2733
2734    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2735        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2736    }
2737
2738    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2739        self.read(cx)
2740            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2741            .nth(1)
2742            .is_some()
2743    }
2744
2745    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2746        let snapshot = self.read(cx);
2747        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2748        let offset_range = range.to_offset(&snapshot);
2749        cursor.seek(&offset_range.start, Bias::Left);
2750        while let Some(item) = cursor.item() {
2751            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2752                break;
2753            }
2754            if item.hunk_info().is_some() {
2755                return true;
2756            }
2757            cursor.next();
2758        }
2759        false
2760    }
2761
2762    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2763        let snapshot = self.read(cx);
2764        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2765        for range in ranges {
2766            let range = range.to_point(&snapshot);
2767            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2768            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2769                .min(snapshot.len());
2770            cursor.seek(&start, Bias::Right);
2771            while let Some(item) = cursor.item() {
2772                if *cursor.start() >= end {
2773                    break;
2774                }
2775                if item.hunk_info().is_some() {
2776                    return true;
2777                }
2778                cursor.next();
2779            }
2780        }
2781        false
2782    }
2783
2784    pub fn expand_or_collapse_diff_hunks_inner(
2785        &mut self,
2786        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2787        expand: bool,
2788        cx: &mut Context<Self>,
2789    ) -> Vec<Edit<MultiBufferOffset>> {
2790        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2791            return Vec::new();
2792        }
2793        self.sync_mut(cx);
2794        let mut snapshot = self.snapshot.get_mut();
2795        let mut excerpt_edits = Vec::new();
2796        let mut last_hunk_row = None;
2797        for (range, end_excerpt_id) in ranges {
2798            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2799                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2800                    continue;
2801                }
2802                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2803                    continue;
2804                }
2805                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2806                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2807                let start = snapshot.excerpt_offset_for_anchor(&start);
2808                let end = snapshot.excerpt_offset_for_anchor(&end);
2809                last_hunk_row = Some(diff_hunk.row_range.start);
2810                excerpt_edits.push(text::Edit {
2811                    old: start..end,
2812                    new: start..end,
2813                });
2814            }
2815        }
2816
2817        Self::sync_diff_transforms(
2818            &mut snapshot,
2819            excerpt_edits,
2820            DiffChangeKind::ExpandOrCollapseHunks { expand },
2821        )
2822    }
2823
2824    pub fn expand_or_collapse_diff_hunks(
2825        &mut self,
2826        ranges: Vec<Range<Anchor>>,
2827        expand: bool,
2828        cx: &mut Context<Self>,
2829    ) {
2830        let snapshot = self.snapshot.borrow().clone();
2831        let ranges = ranges.iter().map(move |range| {
2832            let end_excerpt_id = range.end.excerpt_id;
2833            let range = range.to_point(&snapshot);
2834            let mut peek_end = range.end;
2835            if range.end.row < snapshot.max_row().0 {
2836                peek_end = Point::new(range.end.row + 1, 0);
2837            };
2838            (range.start..peek_end, end_excerpt_id)
2839        });
2840        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2841        if !edits.is_empty() {
2842            self.subscriptions.publish(edits);
2843        }
2844        cx.emit(Event::DiffHunksToggled);
2845        cx.emit(Event::Edited {
2846            edited_buffer: None,
2847        });
2848    }
2849
2850    pub fn resize_excerpt(
2851        &mut self,
2852        id: ExcerptId,
2853        range: Range<text::Anchor>,
2854        cx: &mut Context<Self>,
2855    ) {
2856        self.sync_mut(cx);
2857
2858        let mut snapshot = self.snapshot.get_mut();
2859        let locator = snapshot.excerpt_locator_for_id(id);
2860        let mut new_excerpts = SumTree::default();
2861        let mut cursor = snapshot
2862            .excerpts
2863            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2864        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2865
2866        let prefix = cursor.slice(&Some(locator), Bias::Left);
2867        new_excerpts.append(prefix, ());
2868
2869        let mut excerpt = cursor.item().unwrap().clone();
2870        let old_text_len = excerpt.text_summary.len;
2871
2872        excerpt.range.context.start = range.start;
2873        excerpt.range.context.end = range.end;
2874        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2875
2876        excerpt.text_summary = excerpt
2877            .buffer
2878            .text_summary_for_range(excerpt.range.context.clone());
2879
2880        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2881        let old_start_offset = cursor.start().1;
2882        let new_text_len = excerpt.text_summary.len;
2883        let edit = Edit {
2884            old: old_start_offset..old_start_offset + old_text_len,
2885            new: new_start_offset..new_start_offset + new_text_len,
2886        };
2887
2888        if let Some(last_edit) = edits.last_mut() {
2889            if last_edit.old.end == edit.old.start {
2890                last_edit.old.end = edit.old.end;
2891                last_edit.new.end = edit.new.end;
2892            } else {
2893                edits.push(edit);
2894            }
2895        } else {
2896            edits.push(edit);
2897        }
2898
2899        new_excerpts.push(excerpt, ());
2900
2901        cursor.next();
2902
2903        new_excerpts.append(cursor.suffix(), ());
2904
2905        drop(cursor);
2906        snapshot.excerpts = new_excerpts;
2907
2908        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2909        if !edits.is_empty() {
2910            self.subscriptions.publish(edits);
2911        }
2912        cx.emit(Event::Edited {
2913            edited_buffer: None,
2914        });
2915        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2916        cx.notify();
2917    }
2918
2919    pub fn expand_excerpts(
2920        &mut self,
2921        ids: impl IntoIterator<Item = ExcerptId>,
2922        line_count: u32,
2923        direction: ExpandExcerptDirection,
2924        cx: &mut Context<Self>,
2925    ) {
2926        if line_count == 0 {
2927            return;
2928        }
2929        self.sync_mut(cx);
2930        if !self.excerpts_by_path.is_empty() {
2931            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2932            return;
2933        }
2934        let mut snapshot = self.snapshot.get_mut();
2935
2936        let ids = ids.into_iter().collect::<Vec<_>>();
2937        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2938        let mut new_excerpts = SumTree::default();
2939        let mut cursor = snapshot
2940            .excerpts
2941            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2942        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2943
2944        for locator in &locators {
2945            let prefix = cursor.slice(&Some(locator), Bias::Left);
2946            new_excerpts.append(prefix, ());
2947
2948            let mut excerpt = cursor.item().unwrap().clone();
2949            let old_text_len = excerpt.text_summary.len;
2950
2951            let up_line_count = if direction.should_expand_up() {
2952                line_count
2953            } else {
2954                0
2955            };
2956
2957            let start_row = excerpt
2958                .range
2959                .context
2960                .start
2961                .to_point(&excerpt.buffer)
2962                .row
2963                .saturating_sub(up_line_count);
2964            let start_point = Point::new(start_row, 0);
2965            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2966
2967            let down_line_count = if direction.should_expand_down() {
2968                line_count
2969            } else {
2970                0
2971            };
2972
2973            let mut end_point = excerpt.buffer.clip_point(
2974                excerpt.range.context.end.to_point(&excerpt.buffer)
2975                    + Point::new(down_line_count, 0),
2976                Bias::Left,
2977            );
2978            end_point.column = excerpt.buffer.line_len(end_point.row);
2979            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2980            excerpt.max_buffer_row = end_point.row;
2981
2982            excerpt.text_summary = excerpt
2983                .buffer
2984                .text_summary_for_range(excerpt.range.context.clone());
2985
2986            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2987            let old_start_offset = cursor.start().1;
2988            let new_text_len = excerpt.text_summary.len;
2989            let edit = Edit {
2990                old: old_start_offset..old_start_offset + old_text_len,
2991                new: new_start_offset..new_start_offset + new_text_len,
2992            };
2993
2994            if let Some(last_edit) = edits.last_mut() {
2995                if last_edit.old.end == edit.old.start {
2996                    last_edit.old.end = edit.old.end;
2997                    last_edit.new.end = edit.new.end;
2998                } else {
2999                    edits.push(edit);
3000                }
3001            } else {
3002                edits.push(edit);
3003            }
3004
3005            new_excerpts.push(excerpt, ());
3006
3007            cursor.next();
3008        }
3009
3010        new_excerpts.append(cursor.suffix(), ());
3011
3012        drop(cursor);
3013        snapshot.excerpts = new_excerpts;
3014
3015        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3016        if !edits.is_empty() {
3017            self.subscriptions.publish(edits);
3018        }
3019        cx.emit(Event::Edited {
3020            edited_buffer: None,
3021        });
3022        cx.emit(Event::ExcerptsExpanded { ids });
3023        cx.notify();
3024    }
3025
3026    #[ztracing::instrument(skip_all)]
3027    fn sync(&self, cx: &App) {
3028        let changed = self.buffer_changed_since_sync.replace(false);
3029        if !changed {
3030            return;
3031        }
3032        let edits = Self::sync_from_buffer_changes(
3033            &mut self.snapshot.borrow_mut(),
3034            &self.buffers,
3035            &self.diffs,
3036            cx,
3037        );
3038        if !edits.is_empty() {
3039            self.subscriptions.publish(edits);
3040        }
3041    }
3042
3043    fn sync_mut(&mut self, cx: &App) {
3044        let changed = self.buffer_changed_since_sync.replace(false);
3045        if !changed {
3046            return;
3047        }
3048        let edits =
3049            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3050
3051        if !edits.is_empty() {
3052            self.subscriptions.publish(edits);
3053        }
3054    }
3055
3056    fn sync_from_buffer_changes(
3057        snapshot: &mut MultiBufferSnapshot,
3058        buffers: &BTreeMap<BufferId, BufferState>,
3059        diffs: &HashMap<BufferId, DiffState>,
3060        cx: &App,
3061    ) -> Vec<Edit<MultiBufferOffset>> {
3062        let MultiBufferSnapshot {
3063            excerpts,
3064            buffer_locators: _,
3065            diffs: buffer_diff,
3066            diff_transforms: _,
3067            non_text_state_update_count,
3068            edit_count,
3069            is_dirty,
3070            has_deleted_file,
3071            has_conflict,
3072            has_inverted_diff: _,
3073            singleton: _,
3074            excerpt_ids: _,
3075            replaced_excerpts: _,
3076            trailing_excerpt_update_count: _,
3077            all_diff_hunks_expanded: _,
3078            show_deleted_hunks: _,
3079            use_extended_diff_range: _,
3080            show_headers: _,
3081        } = snapshot;
3082        *is_dirty = false;
3083        *has_deleted_file = false;
3084        *has_conflict = false;
3085
3086        if !diffs.is_empty() {
3087            let mut diffs_to_add = Vec::new();
3088            for (id, diff) in diffs {
3089                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3090                // and use the diff hunk base text ranges to compute diff transforms.
3091                // Those base text ranges are usize, so make sure if the base text changed
3092                // we also update the diff snapshot so that we don't use stale offsets
3093                if buffer_diff.get(id).is_none_or(|existing_diff| {
3094                    if !existing_diff.is_inverted {
3095                        return false;
3096                    }
3097                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3098                    base_text.remote_id() != existing_diff.base_text().remote_id()
3099                        || base_text
3100                            .version()
3101                            .changed_since(existing_diff.base_text().version())
3102                }) {
3103                    if diffs_to_add.capacity() == 0 {
3104                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3105                        // meaning re-allocations will be fairly expensive
3106                        diffs_to_add.reserve(diffs.len());
3107                    }
3108                    diffs_to_add.push((*id, diff.snapshot(cx)));
3109                }
3110            }
3111            buffer_diff.extend(diffs_to_add);
3112        }
3113
3114        let mut excerpts_to_edit = Vec::new();
3115        let mut non_text_state_updated = false;
3116        let mut edited = false;
3117        for buffer_state in buffers.values() {
3118            let buffer = buffer_state.buffer.read(cx);
3119            let version = buffer.version();
3120            let non_text_state_update_count = buffer.non_text_state_update_count();
3121
3122            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3123            let buffer_non_text_state_updated =
3124                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3125            if buffer_edited || buffer_non_text_state_updated {
3126                *buffer_state.last_version.borrow_mut() = version;
3127                buffer_state
3128                    .last_non_text_state_update_count
3129                    .set(non_text_state_update_count);
3130                excerpts_to_edit.extend(
3131                    buffer_state
3132                        .excerpts
3133                        .iter()
3134                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3135                );
3136            }
3137
3138            edited |= buffer_edited;
3139            non_text_state_updated |= buffer_non_text_state_updated;
3140            *is_dirty |= buffer.is_dirty();
3141            *has_deleted_file |= buffer
3142                .file()
3143                .is_some_and(|file| file.disk_state().is_deleted());
3144            *has_conflict |= buffer.has_conflict();
3145        }
3146        if edited {
3147            *edit_count += 1;
3148        }
3149        if non_text_state_updated {
3150            *non_text_state_update_count += 1;
3151        }
3152
3153        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3154
3155        let mut edits = Vec::new();
3156        let mut new_excerpts = SumTree::default();
3157        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3158
3159        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3160            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3161            let old_excerpt = cursor.item().unwrap();
3162            let buffer = buffer.read(cx);
3163            let buffer_id = buffer.remote_id();
3164            let mut new_excerpt;
3165            if buffer_edited {
3166                edits.extend(
3167                    buffer
3168                        .edits_since_in_range::<usize>(
3169                            old_excerpt.buffer.version(),
3170                            old_excerpt.range.context.clone(),
3171                        )
3172                        .map(|edit| {
3173                            let excerpt_old_start = cursor.start().1;
3174                            let excerpt_new_start =
3175                                ExcerptDimension(new_excerpts.summary().text.len);
3176                            let old_start = excerpt_old_start + edit.old.start;
3177                            let old_end = excerpt_old_start + edit.old.end;
3178                            let new_start = excerpt_new_start + edit.new.start;
3179                            let new_end = excerpt_new_start + edit.new.end;
3180                            Edit {
3181                                old: old_start..old_end,
3182                                new: new_start..new_end,
3183                            }
3184                        }),
3185                );
3186
3187                new_excerpt = Excerpt::new(
3188                    old_excerpt.id,
3189                    locator.clone(),
3190                    buffer_id,
3191                    Arc::new(buffer.snapshot()),
3192                    old_excerpt.range.clone(),
3193                    old_excerpt.has_trailing_newline,
3194                );
3195            } else {
3196                new_excerpt = old_excerpt.clone();
3197                new_excerpt.buffer = Arc::new(buffer.snapshot());
3198            }
3199
3200            new_excerpts.push(new_excerpt, ());
3201            cursor.next();
3202        }
3203        new_excerpts.append(cursor.suffix(), ());
3204
3205        drop(cursor);
3206        *excerpts = new_excerpts;
3207
3208        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3209    }
3210
3211    fn sync_diff_transforms(
3212        snapshot: &mut MultiBufferSnapshot,
3213        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3214        change_kind: DiffChangeKind,
3215    ) -> Vec<Edit<MultiBufferOffset>> {
3216        if excerpt_edits.is_empty() {
3217            return vec![];
3218        }
3219
3220        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3221        let mut old_diff_transforms = snapshot
3222            .diff_transforms
3223            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3224        let mut new_diff_transforms = SumTree::default();
3225        let mut old_expanded_hunks = HashSet::default();
3226        let mut output_edits = Vec::new();
3227        let mut output_delta = 0_isize;
3228        let mut at_transform_boundary = true;
3229        let mut end_of_current_insert = None;
3230
3231        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3232        while let Some(edit) = excerpt_edits.next() {
3233            excerpts.seek_forward(&edit.new.start, Bias::Right);
3234            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3235                excerpts.prev();
3236            }
3237
3238            // Keep any transforms that are before the edit.
3239            if at_transform_boundary {
3240                at_transform_boundary = false;
3241                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3242                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3243                if let Some(transform) = old_diff_transforms.item()
3244                    && old_diff_transforms.end().0 == edit.old.start
3245                    && old_diff_transforms.start().0 < edit.old.start
3246                {
3247                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3248                    old_diff_transforms.next();
3249                }
3250            }
3251
3252            // Compute the start of the edit in output coordinates.
3253            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3254            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3255            let edit_new_start =
3256                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3257
3258            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3259                &edit,
3260                &mut excerpts,
3261                &mut old_diff_transforms,
3262                &mut new_diff_transforms,
3263                &mut end_of_current_insert,
3264                &mut old_expanded_hunks,
3265                snapshot,
3266                change_kind,
3267            );
3268
3269            // Compute the end of the edit in output coordinates.
3270            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3271            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3272            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3273            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3274            let output_edit = Edit {
3275                old: edit_old_start..edit_old_end,
3276                new: edit_new_start..edit_new_end,
3277            };
3278
3279            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3280            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3281            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3282                output_edits.push(output_edit);
3283            }
3284
3285            // If this is the last edit that intersects the current diff transform,
3286            // then recreate the content up to the end of this transform, to prepare
3287            // for reusing additional slices of the old transforms.
3288            if excerpt_edits
3289                .peek()
3290                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3291            {
3292                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3293                    && match old_diff_transforms.item() {
3294                        Some(DiffTransform::BufferContent {
3295                            inserted_hunk_info: Some(hunk),
3296                            ..
3297                        }) => excerpts.item().is_some_and(|excerpt| {
3298                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3299                                && diff.is_inverted
3300                            {
3301                                return true;
3302                            }
3303                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3304                        }),
3305                        _ => true,
3306                    };
3307
3308                let mut excerpt_offset = edit.new.end;
3309                if !keep_next_old_transform {
3310                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3311                    old_diff_transforms.next();
3312                }
3313
3314                old_expanded_hunks.clear();
3315                Self::push_buffer_content_transform(
3316                    snapshot,
3317                    &mut new_diff_transforms,
3318                    excerpt_offset,
3319                    end_of_current_insert,
3320                );
3321                at_transform_boundary = true;
3322            }
3323        }
3324
3325        // Keep any transforms that are after the last edit.
3326        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3327
3328        // Ensure there's always at least one buffer content transform.
3329        if new_diff_transforms.is_empty() {
3330            new_diff_transforms.push(
3331                DiffTransform::BufferContent {
3332                    summary: Default::default(),
3333                    inserted_hunk_info: None,
3334                },
3335                (),
3336            );
3337        }
3338
3339        drop(old_diff_transforms);
3340        drop(excerpts);
3341        snapshot.diff_transforms = new_diff_transforms;
3342        snapshot.edit_count += 1;
3343
3344        #[cfg(any(test, feature = "test-support"))]
3345        snapshot.check_invariants();
3346        output_edits
3347    }
3348
3349    fn recompute_diff_transforms_for_edit(
3350        edit: &Edit<ExcerptOffset>,
3351        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3352        old_diff_transforms: &mut Cursor<
3353            DiffTransform,
3354            Dimensions<ExcerptOffset, MultiBufferOffset>,
3355        >,
3356        new_diff_transforms: &mut SumTree<DiffTransform>,
3357        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3358        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3359        snapshot: &MultiBufferSnapshot,
3360        change_kind: DiffChangeKind,
3361    ) -> bool {
3362        log::trace!(
3363            "recomputing diff transform for edit {:?} => {:?}",
3364            edit.old.start..edit.old.end,
3365            edit.new.start..edit.new.end
3366        );
3367
3368        // Record which hunks were previously expanded.
3369        while let Some(item) = old_diff_transforms.item() {
3370            if let Some(hunk_info) = item.hunk_info() {
3371                log::trace!(
3372                    "previously expanded hunk at {:?}",
3373                    old_diff_transforms.start()
3374                );
3375                old_expanded_hunks.insert(hunk_info);
3376            }
3377            if old_diff_transforms.end().0 > edit.old.end {
3378                break;
3379            }
3380            old_diff_transforms.next();
3381        }
3382
3383        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3384        // For inverted diffs, hunks are always shown, so we can't skip this.
3385        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3386        if old_expanded_hunks.is_empty()
3387            && change_kind == DiffChangeKind::BufferEdited
3388            && !all_diff_hunks_expanded
3389            && !snapshot.has_inverted_diff
3390        {
3391            return false;
3392        }
3393
3394        // Visit each excerpt that intersects the edit.
3395        let mut did_expand_hunks = false;
3396        while let Some(excerpt) = excerpts.item() {
3397            // Recompute the expanded hunks in the portion of the excerpt that
3398            // intersects the edit.
3399            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3400                let buffer = &excerpt.buffer;
3401                let excerpt_start = *excerpts.start();
3402                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3403                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3404                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3405                let edit_buffer_start =
3406                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3407                let edit_buffer_end =
3408                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3409                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3410
3411                if diff.is_inverted {
3412                    for hunk in diff.hunks_intersecting_base_text_range(
3413                        edit_buffer_start..edit_buffer_end,
3414                        diff.original_buffer_snapshot(),
3415                    ) {
3416                        did_expand_hunks = true;
3417                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3418                        if hunk_buffer_range.start < excerpt_buffer_start {
3419                            log::trace!("skipping hunk that starts before excerpt");
3420                            continue;
3421                        }
3422                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3423                        let hunk_excerpt_start = excerpt_start
3424                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3425                        let hunk_excerpt_end = excerpt_end
3426                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3427                        Self::push_buffer_content_transform(
3428                            snapshot,
3429                            new_diff_transforms,
3430                            hunk_excerpt_start,
3431                            *end_of_current_insert,
3432                        );
3433                        if !hunk_buffer_range.is_empty() {
3434                            let hunk_info = DiffTransformHunkInfo {
3435                                excerpt_id: excerpt.id,
3436                                hunk_start_anchor: hunk.buffer_range.start,
3437                                hunk_secondary_status: hunk.secondary_status,
3438                                is_logically_deleted: true,
3439                            };
3440                            *end_of_current_insert =
3441                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3442                        }
3443                    }
3444                } else {
3445                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3446                        ..buffer.anchor_after(edit_buffer_end);
3447                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3448                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3449                            continue;
3450                        }
3451
3452                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3453                        if hunk_buffer_range.start < excerpt_buffer_start {
3454                            log::trace!("skipping hunk that starts before excerpt");
3455                            continue;
3456                        }
3457
3458                        let hunk_info = DiffTransformHunkInfo {
3459                            excerpt_id: excerpt.id,
3460                            hunk_start_anchor: hunk.buffer_range.start,
3461                            hunk_secondary_status: hunk.secondary_status,
3462                            is_logically_deleted: false,
3463                        };
3464
3465                        let hunk_excerpt_start = excerpt_start
3466                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3467                        let hunk_excerpt_end = excerpt_end
3468                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3469
3470                        Self::push_buffer_content_transform(
3471                            snapshot,
3472                            new_diff_transforms,
3473                            hunk_excerpt_start,
3474                            *end_of_current_insert,
3475                        );
3476
3477                        // For every existing hunk, determine if it was previously expanded
3478                        // and if it should currently be expanded.
3479                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3480                        let should_expand_hunk = match &change_kind {
3481                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3482                                was_previously_expanded || all_diff_hunks_expanded
3483                            }
3484                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3485                                let intersects = hunk_buffer_range.is_empty()
3486                                    || hunk_buffer_range.end > edit_buffer_start;
3487                                if *expand {
3488                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3489                                } else {
3490                                    !intersects
3491                                        && (was_previously_expanded || all_diff_hunks_expanded)
3492                                }
3493                            }
3494                            _ => was_previously_expanded || all_diff_hunks_expanded,
3495                        };
3496
3497                        if should_expand_hunk {
3498                            did_expand_hunks = true;
3499                            log::trace!(
3500                                "expanding hunk {:?}, excerpt:{:?}",
3501                                hunk_excerpt_start..hunk_excerpt_end,
3502                                excerpt.id
3503                            );
3504
3505                            if !hunk.diff_base_byte_range.is_empty()
3506                                && hunk_buffer_range.start >= edit_buffer_start
3507                                && hunk_buffer_range.start <= excerpt_buffer_end
3508                                && snapshot.show_deleted_hunks
3509                            {
3510                                let base_text = diff.base_text();
3511                                let mut text_cursor =
3512                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3513                                let mut base_text_summary = text_cursor
3514                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3515
3516                                let mut has_trailing_newline = false;
3517                                if base_text_summary.last_line_chars > 0 {
3518                                    base_text_summary += TextSummary::newline();
3519                                    has_trailing_newline = true;
3520                                }
3521
3522                                new_diff_transforms.push(
3523                                    DiffTransform::DeletedHunk {
3524                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3525                                        summary: base_text_summary,
3526                                        buffer_id: excerpt.buffer_id,
3527                                        hunk_info,
3528                                        has_trailing_newline,
3529                                    },
3530                                    (),
3531                                );
3532                            }
3533
3534                            if !hunk_buffer_range.is_empty() {
3535                                *end_of_current_insert =
3536                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3537                            }
3538                        }
3539                    }
3540                }
3541            }
3542
3543            if excerpts.end() <= edit.new.end {
3544                excerpts.next();
3545            } else {
3546                break;
3547            }
3548        }
3549
3550        did_expand_hunks || !old_expanded_hunks.is_empty()
3551    }
3552
3553    fn append_diff_transforms(
3554        new_transforms: &mut SumTree<DiffTransform>,
3555        subtree: SumTree<DiffTransform>,
3556    ) {
3557        if let Some(DiffTransform::BufferContent {
3558            inserted_hunk_info,
3559            summary,
3560        }) = subtree.first()
3561            && Self::extend_last_buffer_content_transform(
3562                new_transforms,
3563                *inserted_hunk_info,
3564                *summary,
3565            )
3566        {
3567            let mut cursor = subtree.cursor::<()>(());
3568            cursor.next();
3569            cursor.next();
3570            new_transforms.append(cursor.suffix(), ());
3571            return;
3572        }
3573        new_transforms.append(subtree, ());
3574    }
3575
3576    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3577        if let DiffTransform::BufferContent {
3578            inserted_hunk_info: inserted_hunk_anchor,
3579            summary,
3580        } = transform
3581            && Self::extend_last_buffer_content_transform(
3582                new_transforms,
3583                inserted_hunk_anchor,
3584                summary,
3585            )
3586        {
3587            return;
3588        }
3589        new_transforms.push(transform, ());
3590    }
3591
3592    fn push_buffer_content_transform(
3593        old_snapshot: &MultiBufferSnapshot,
3594        new_transforms: &mut SumTree<DiffTransform>,
3595        end_offset: ExcerptOffset,
3596        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3597    ) {
3598        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3599            (end_offset.min(insertion_end_offset), Some(hunk_info))
3600        });
3601        let unchanged_region = [(end_offset, None)];
3602
3603        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3604        {
3605            let start_offset = new_transforms.summary().excerpt_len();
3606            if end_offset <= start_offset {
3607                continue;
3608            }
3609            let summary_to_add = old_snapshot
3610                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3611
3612            if !Self::extend_last_buffer_content_transform(
3613                new_transforms,
3614                inserted_hunk_info,
3615                summary_to_add,
3616            ) {
3617                new_transforms.push(
3618                    DiffTransform::BufferContent {
3619                        summary: summary_to_add,
3620                        inserted_hunk_info,
3621                    },
3622                    (),
3623                )
3624            }
3625        }
3626    }
3627
3628    fn extend_last_buffer_content_transform(
3629        new_transforms: &mut SumTree<DiffTransform>,
3630        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3631        summary_to_add: MBTextSummary,
3632    ) -> bool {
3633        let mut did_extend = false;
3634        new_transforms.update_last(
3635            |last_transform| {
3636                if let DiffTransform::BufferContent {
3637                    summary,
3638                    inserted_hunk_info: inserted_hunk_anchor,
3639                } = last_transform
3640                    && *inserted_hunk_anchor == new_inserted_hunk_info
3641                {
3642                    *summary += summary_to_add;
3643                    did_extend = true;
3644                }
3645            },
3646            (),
3647        );
3648        did_extend
3649    }
3650
3651    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3652        let snapshot = self.snapshot(cx);
3653        let excerpt_id = range.end.excerpt_id;
3654        let point_range = range.to_point(&snapshot);
3655        let expand = !self.single_hunk_is_expanded(range, cx);
3656        let edits =
3657            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3658        if !edits.is_empty() {
3659            self.subscriptions.publish(edits);
3660        }
3661        cx.emit(Event::DiffHunksToggled);
3662        cx.emit(Event::Edited {
3663            edited_buffer: None,
3664        });
3665    }
3666}
3667
3668fn build_excerpt_ranges(
3669    ranges: impl IntoIterator<Item = Range<Point>>,
3670    context_line_count: u32,
3671    buffer_snapshot: &BufferSnapshot,
3672) -> Vec<ExcerptRange<Point>> {
3673    ranges
3674        .into_iter()
3675        .map(|range| {
3676            let start_row = range.start.row.saturating_sub(context_line_count);
3677            let start = Point::new(start_row, 0);
3678            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3679            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3680            ExcerptRange {
3681                context: start..end,
3682                primary: range,
3683            }
3684        })
3685        .collect()
3686}
3687
3688#[cfg(any(test, feature = "test-support"))]
3689impl MultiBuffer {
3690    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3691        let buffer = cx.new(|cx| Buffer::local(text, cx));
3692        cx.new(|cx| Self::singleton(buffer, cx))
3693    }
3694
3695    pub fn build_multi<const COUNT: usize>(
3696        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3697        cx: &mut gpui::App,
3698    ) -> Entity<Self> {
3699        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3700        for (text, ranges) in excerpts {
3701            let buffer = cx.new(|cx| Buffer::local(text, cx));
3702            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3703            multi.update(cx, |multi, cx| {
3704                multi.push_excerpts(buffer, excerpt_ranges, cx)
3705            });
3706        }
3707
3708        multi
3709    }
3710
3711    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3712        cx.new(|cx| Self::singleton(buffer, cx))
3713    }
3714
3715    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3716        cx.new(|cx| {
3717            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3718            let mutation_count = rng.random_range(1..=5);
3719            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3720            multibuffer
3721        })
3722    }
3723
3724    pub fn randomly_edit(
3725        &mut self,
3726        rng: &mut impl rand::Rng,
3727        edit_count: usize,
3728        cx: &mut Context<Self>,
3729    ) {
3730        use util::RandomCharIter;
3731
3732        let snapshot = self.read(cx);
3733        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3734        let mut last_end = None;
3735        for _ in 0..edit_count {
3736            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3737                break;
3738            }
3739
3740            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3741            let end =
3742                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3743            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3744            last_end = Some(end);
3745
3746            let mut range = start..end;
3747            if rng.random_bool(0.2) {
3748                mem::swap(&mut range.start, &mut range.end);
3749            }
3750
3751            let new_text_len = rng.random_range(0..10);
3752            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3753
3754            edits.push((range, new_text.into()));
3755        }
3756        log::info!("mutating multi-buffer with {:?}", edits);
3757        drop(snapshot);
3758
3759        self.edit(edits, None, cx);
3760    }
3761
3762    pub fn randomly_edit_excerpts(
3763        &mut self,
3764        rng: &mut impl rand::Rng,
3765        mutation_count: usize,
3766        cx: &mut Context<Self>,
3767    ) {
3768        use rand::prelude::*;
3769        use std::env;
3770        use util::RandomCharIter;
3771
3772        let max_excerpts = env::var("MAX_EXCERPTS")
3773            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3774            .unwrap_or(5);
3775
3776        let mut buffers = Vec::new();
3777        for _ in 0..mutation_count {
3778            if rng.random_bool(0.05) {
3779                log::info!("Clearing multi-buffer");
3780                self.clear(cx);
3781                continue;
3782            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3783                let ids = self.excerpt_ids();
3784                let mut excerpts = HashSet::default();
3785                for _ in 0..rng.random_range(0..ids.len()) {
3786                    excerpts.extend(ids.choose(rng).copied());
3787                }
3788
3789                let line_count = rng.random_range(0..5);
3790
3791                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3792
3793                self.expand_excerpts(
3794                    excerpts.iter().cloned(),
3795                    line_count,
3796                    ExpandExcerptDirection::UpAndDown,
3797                    cx,
3798                );
3799                continue;
3800            }
3801
3802            let excerpt_ids = self.excerpt_ids();
3803            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3804                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3805                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3806                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3807                    let buffer = buffers.last().unwrap().read(cx);
3808                    log::info!(
3809                        "Creating new buffer {} with text: {:?}",
3810                        buffer.remote_id(),
3811                        buffer.text()
3812                    );
3813                    buffers.last().unwrap().clone()
3814                } else {
3815                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3816                };
3817
3818                let buffer = buffer_handle.read(cx);
3819                let buffer_text = buffer.text();
3820                let ranges = (0..rng.random_range(0..5))
3821                    .map(|_| {
3822                        let end_ix =
3823                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3824                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3825                        ExcerptRange::new(start_ix..end_ix)
3826                    })
3827                    .collect::<Vec<_>>();
3828                log::info!(
3829                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3830                    buffer_handle.read(cx).remote_id(),
3831                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3832                    ranges
3833                        .iter()
3834                        .map(|r| &buffer_text[r.context.clone()])
3835                        .collect::<Vec<_>>()
3836                );
3837
3838                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3839                log::info!("Inserted with ids: {:?}", excerpt_id);
3840            } else {
3841                let remove_count = rng.random_range(1..=excerpt_ids.len());
3842                let mut excerpts_to_remove = excerpt_ids
3843                    .choose_multiple(rng, remove_count)
3844                    .cloned()
3845                    .collect::<Vec<_>>();
3846                let snapshot = self.snapshot.borrow();
3847                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3848                drop(snapshot);
3849                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3850                self.remove_excerpts(excerpts_to_remove, cx);
3851            }
3852        }
3853    }
3854
3855    pub fn randomly_mutate(
3856        &mut self,
3857        rng: &mut impl rand::Rng,
3858        mutation_count: usize,
3859        cx: &mut Context<Self>,
3860    ) {
3861        use rand::prelude::*;
3862
3863        if rng.random_bool(0.7) || self.singleton {
3864            let buffer = self
3865                .buffers
3866                .values()
3867                .choose(rng)
3868                .map(|state| state.buffer.clone());
3869
3870            if let Some(buffer) = buffer {
3871                buffer.update(cx, |buffer, cx| {
3872                    if rng.random() {
3873                        buffer.randomly_edit(rng, mutation_count, cx);
3874                    } else {
3875                        buffer.randomly_undo_redo(rng, cx);
3876                    }
3877                });
3878            } else {
3879                self.randomly_edit(rng, mutation_count, cx);
3880            }
3881        } else {
3882            self.randomly_edit_excerpts(rng, mutation_count, cx);
3883        }
3884
3885        self.check_invariants(cx);
3886    }
3887
3888    fn check_invariants(&self, cx: &App) {
3889        self.read(cx).check_invariants();
3890    }
3891}
3892
3893impl EventEmitter<Event> for MultiBuffer {}
3894
3895impl MultiBufferSnapshot {
3896    pub fn text(&self) -> String {
3897        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3898            .map(|chunk| chunk.text)
3899            .collect()
3900    }
3901
3902    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3903        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3904            .flat_map(|c| c.chars().rev())
3905    }
3906
3907    fn reversed_chunks_in_range(
3908        &self,
3909        range: Range<MultiBufferOffset>,
3910    ) -> ReversedMultiBufferChunks<'_> {
3911        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3912        cursor.seek(&range.end);
3913        let current_chunks = cursor.region().as_ref().map(|region| {
3914            let start_overshoot = range.start.saturating_sub(region.range.start);
3915            let end_overshoot = range.end - region.range.start;
3916            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3917            let start = region.buffer_range.start + start_overshoot;
3918            region.buffer.reversed_chunks_in_range(start..end)
3919        });
3920        ReversedMultiBufferChunks {
3921            cursor,
3922            current_chunks,
3923            start: range.start,
3924            offset: range.end,
3925        }
3926    }
3927
3928    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3929        let offset = position.to_offset(self);
3930        self.text_for_range(offset..self.len())
3931            .flat_map(|chunk| chunk.chars())
3932    }
3933
3934    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3935        self.chunks(range, false).map(|chunk| chunk.text)
3936    }
3937
3938    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3939        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3940            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3941    }
3942
3943    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3944    where
3945        T: ToOffset,
3946    {
3947        let position = position.to_offset(self);
3948        position == self.clip_offset(position, Bias::Left)
3949            && self
3950                .bytes_in_range(position..self.len())
3951                .flatten()
3952                .copied()
3953                .take(needle.len())
3954                .eq(needle.bytes())
3955    }
3956
3957    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3958        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3959    }
3960
3961    pub fn diff_hunks_in_range<T: ToPoint>(
3962        &self,
3963        range: Range<T>,
3964    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3965        let query_range = range.start.to_point(self)..range.end.to_point(self);
3966        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3967            let diff = self.diffs.get(&buffer.remote_id())?;
3968            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3969                if diff.is_inverted {
3970                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3971                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3972                    Box::new(
3973                        diff.hunks_intersecting_base_text_range(
3974                            buffer_start..buffer_end,
3975                            diff.original_buffer_snapshot(),
3976                        )
3977                        .map(move |hunk| (hunk, buffer, true)),
3978                    )
3979                } else {
3980                    let buffer_start = buffer.anchor_before(buffer_range.start);
3981                    let buffer_end = buffer.anchor_after(buffer_range.end);
3982                    Box::new(
3983                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3984                            .map(move |hunk| (hunk, buffer, false)),
3985                    )
3986                };
3987            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3988                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3989                    return None;
3990                }
3991                let range = if is_inverted {
3992                    hunk.diff_base_byte_range.to_point(&buffer)
3993                } else {
3994                    hunk.range.clone()
3995                };
3996                Some((range, (hunk, is_inverted)))
3997            }))
3998        })
3999        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4000            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4001            {
4002                return None;
4003            }
4004            let end_row = if range.end.column == 0 {
4005                range.end.row
4006            } else {
4007                range.end.row + 1
4008            };
4009
4010            let word_diffs =
4011                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4012                    .then(|| {
4013                        let mut word_diffs = Vec::new();
4014
4015                        if self.show_deleted_hunks || is_inverted {
4016                            let hunk_start_offset = if is_inverted {
4017                                Anchor::in_buffer(
4018                                    excerpt.id,
4019                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4020                                )
4021                                .to_offset(self)
4022                            } else {
4023                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4024                                    .to_offset(self)
4025                            };
4026
4027                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4028                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4029                            }));
4030                        }
4031
4032                        if !is_inverted {
4033                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4034                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4035                            }));
4036                        }
4037                        word_diffs
4038                    })
4039                    .unwrap_or_default();
4040
4041            let buffer_range = if is_inverted {
4042                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4043                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4044            } else {
4045                hunk.buffer_range.clone()
4046            };
4047            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4048                DiffHunkStatusKind::Deleted
4049            } else if hunk.diff_base_byte_range.is_empty() {
4050                DiffHunkStatusKind::Added
4051            } else {
4052                DiffHunkStatusKind::Modified
4053            };
4054            Some(MultiBufferDiffHunk {
4055                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4056                buffer_id: excerpt.buffer_id,
4057                excerpt_id: excerpt.id,
4058                buffer_range,
4059                word_diffs,
4060                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4061                    ..BufferOffset(hunk.diff_base_byte_range.end),
4062                status: DiffHunkStatus {
4063                    kind: status_kind,
4064                    secondary: hunk.secondary_status,
4065                },
4066            })
4067        })
4068    }
4069
4070    fn excerpts_for_range<T: ToOffset>(
4071        &self,
4072        range: Range<T>,
4073    ) -> impl Iterator<Item = &Excerpt> + '_ {
4074        let range = range.start.to_offset(self)..range.end.to_offset(self);
4075        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4076        cursor.seek(&range.start);
4077        std::iter::from_fn(move || {
4078            let region = cursor.region()?;
4079            if region.range.start > range.end
4080                || region.range.start == range.end && region.range.start > range.start
4081            {
4082                return None;
4083            }
4084            let excerpt = region.excerpt;
4085            cursor.next_excerpt_forwards();
4086            Some(excerpt)
4087        })
4088    }
4089
4090    pub fn excerpt_ids_for_range<T: ToOffset>(
4091        &self,
4092        range: Range<T>,
4093    ) -> impl Iterator<Item = ExcerptId> + '_ {
4094        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4095    }
4096
4097    pub fn buffer_ids_for_range<T: ToOffset>(
4098        &self,
4099        range: Range<T>,
4100    ) -> impl Iterator<Item = BufferId> + '_ {
4101        self.excerpts_for_range(range)
4102            .map(|excerpt| excerpt.buffer_id)
4103    }
4104
4105    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4106    ///
4107    /// The passed in anchors must be ordered.
4108    pub fn text_anchors_to_visible_anchors(
4109        &self,
4110        anchors: impl IntoIterator<Item = text::Anchor>,
4111    ) -> Vec<Option<Anchor>> {
4112        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4113        let mut anchors = anchors.into_iter().peekable();
4114        let mut result = Vec::new();
4115        'anchors: while let Some(anchor) = anchors.peek() {
4116            let Some(buffer_id) = anchor.buffer_id else {
4117                anchors.next();
4118                result.push(None);
4119                continue 'anchors;
4120            };
4121            let mut same_buffer_anchors =
4122                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4123
4124            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4125                let Some(mut next) = same_buffer_anchors.next() else {
4126                    continue 'anchors;
4127                };
4128                'excerpts: for locator in locators.iter() {
4129                    if cursor.seek_forward(&Some(locator), Bias::Left)
4130                        && let Some(excerpt) = cursor.item()
4131                    {
4132                        loop {
4133                            // anchor is before the first excerpt
4134                            if excerpt
4135                                .range
4136                                .context
4137                                .start
4138                                .cmp(&next, &excerpt.buffer)
4139                                .is_gt()
4140                            {
4141                                // so we skip it and try the next anchor
4142                                result.push(None);
4143                                match same_buffer_anchors.next() {
4144                                    Some(anchor) => next = anchor,
4145                                    None => continue 'anchors,
4146                                }
4147                            // anchor is within the excerpt
4148                            } else if excerpt
4149                                .range
4150                                .context
4151                                .end
4152                                .cmp(&next, &excerpt.buffer)
4153                                .is_ge()
4154                            {
4155                                // record it and all following anchors that are within
4156                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4157                                result.extend(
4158                                    same_buffer_anchors
4159                                        .peeking_take_while(|a| {
4160                                            excerpt
4161                                                .range
4162                                                .context
4163                                                .end
4164                                                .cmp(a, &excerpt.buffer)
4165                                                .is_ge()
4166                                        })
4167                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4168                                );
4169                                match same_buffer_anchors.next() {
4170                                    Some(anchor) => next = anchor,
4171                                    None => continue 'anchors,
4172                                }
4173                            // anchor is after the excerpt, try the next one
4174                            } else {
4175                                continue 'excerpts;
4176                            }
4177                        }
4178                    }
4179                }
4180                // account for `next`
4181                result.push(None);
4182            }
4183            result.extend(same_buffer_anchors.map(|_| None));
4184        }
4185
4186        result
4187    }
4188
4189    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4190        &self,
4191        ranges: impl Iterator<Item = Range<T>>,
4192    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4193        ranges.flat_map(|range| {
4194            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4195                .into_iter()
4196        })
4197    }
4198
4199    pub fn range_to_buffer_ranges<R, T>(
4200        &self,
4201        range: R,
4202    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4203    where
4204        R: RangeBounds<T>,
4205        T: ToOffset,
4206    {
4207        self.range_to_buffer_ranges_with_context(range)
4208            .into_iter()
4209            .map(|(buffer, range, id, _context)| (buffer, range, id))
4210            .collect()
4211    }
4212
4213    pub fn range_to_buffer_ranges_with_context<R, T>(
4214        &self,
4215        range: R,
4216    ) -> Vec<(
4217        &BufferSnapshot,
4218        Range<BufferOffset>,
4219        ExcerptId,
4220        Range<text::Anchor>,
4221    )>
4222    where
4223        R: RangeBounds<T>,
4224        T: ToOffset,
4225    {
4226        let start = match range.start_bound() {
4227            Bound::Included(start) => start.to_offset(self),
4228            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4229            Bound::Unbounded => MultiBufferOffset::ZERO,
4230        };
4231        let end_bound = match range.end_bound() {
4232            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4233            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4234            Bound::Unbounded => Bound::Unbounded,
4235        };
4236        let bounds = (Bound::Included(start), end_bound);
4237
4238        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4239        cursor.seek(&start);
4240
4241        let mut result: Vec<(
4242            &BufferSnapshot,
4243            Range<BufferOffset>,
4244            ExcerptId,
4245            Range<text::Anchor>,
4246        )> = Vec::new();
4247        while let Some(region) = cursor.region() {
4248            let dominated_by_end_bound = match end_bound {
4249                Bound::Included(end) => region.range.start > end,
4250                Bound::Excluded(end) => region.range.start >= end,
4251                Bound::Unbounded => false,
4252            };
4253            if dominated_by_end_bound {
4254                break;
4255            }
4256            if region.is_main_buffer {
4257                let start_overshoot = start.saturating_sub(region.range.start);
4258                let end_offset = match end_bound {
4259                    Bound::Included(end) | Bound::Excluded(end) => end,
4260                    Bound::Unbounded => region.range.end,
4261                };
4262                let end_overshoot = end_offset.saturating_sub(region.range.start);
4263                let start = region
4264                    .buffer_range
4265                    .end
4266                    .min(region.buffer_range.start + start_overshoot);
4267                let end = region
4268                    .buffer_range
4269                    .end
4270                    .min(region.buffer_range.start + end_overshoot);
4271                let context = region.excerpt.range.context.clone();
4272                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4273                    *excerpt_id == region.excerpt.id && prev_range.end == start
4274                }) {
4275                    prev.1.end = end;
4276                } else {
4277                    result.push((region.buffer, start..end, region.excerpt.id, context));
4278                }
4279            }
4280            cursor.next();
4281        }
4282
4283        if let Some(excerpt) = cursor.excerpt() {
4284            let dominated_by_prev_excerpt =
4285                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4286            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4287                let excerpt_position = self.len();
4288                if bounds.contains(&excerpt_position) {
4289                    let buffer_offset =
4290                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4291                    let context = excerpt.range.context.clone();
4292                    result.push((
4293                        &excerpt.buffer,
4294                        buffer_offset..buffer_offset,
4295                        excerpt.id,
4296                        context,
4297                    ));
4298                }
4299            }
4300        }
4301
4302        result
4303    }
4304
4305    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4306        &self,
4307        range: Range<T>,
4308    ) -> impl Iterator<
4309        Item = (
4310            &BufferSnapshot,
4311            Range<BufferOffset>,
4312            ExcerptId,
4313            Option<Anchor>,
4314        ),
4315    > + '_ {
4316        let start = range.start.to_offset(self);
4317        let end = range.end.to_offset(self);
4318
4319        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4320        cursor.seek(&start);
4321
4322        std::iter::from_fn(move || {
4323            let region = cursor.region()?;
4324            if region.range.start > end {
4325                return None;
4326            }
4327            let start_overshoot = start.saturating_sub(region.range.start);
4328            let end_overshoot = end.saturating_sub(region.range.start);
4329            let start = region
4330                .buffer_range
4331                .end
4332                .min(region.buffer_range.start + start_overshoot);
4333            let end = region
4334                .buffer_range
4335                .end
4336                .min(region.buffer_range.start + end_overshoot);
4337
4338            let region_excerpt_id = region.excerpt.id;
4339            let deleted_hunk_anchor = if region.is_main_buffer {
4340                None
4341            } else {
4342                Some(self.anchor_before(region.range.start))
4343            };
4344            let result = (
4345                region.buffer,
4346                start..end,
4347                region_excerpt_id,
4348                deleted_hunk_anchor,
4349            );
4350            cursor.next();
4351            Some(result)
4352        })
4353    }
4354
4355    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4356    /// coordinates.
4357    ///
4358    /// The given callback will be called for every excerpt intersecting the given range. It will
4359    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4360    /// The callback should return an iterator of metadata items from that buffer, each paired
4361    /// with a buffer range.
4362    ///
4363    /// The returned iterator yields each of these metadata items, paired with its range in
4364    /// multi-buffer coordinates.
4365    fn lift_buffer_metadata<'a, MBD, M, I>(
4366        &'a self,
4367        query_range: Range<MBD>,
4368        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4369    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4370    where
4371        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4372        MBD: MultiBufferDimension
4373            + Ord
4374            + Sub<Output = MBD::TextDimension>
4375            + ops::Add<MBD::TextDimension, Output = MBD>
4376            + ops::AddAssign<MBD::TextDimension>,
4377        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4378            + ops::Add<Output = MBD::TextDimension>
4379            + AddAssign<MBD::TextDimension>
4380            + Ord,
4381    {
4382        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4383        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4384
4385        // Find the excerpt and buffer offset where the given range ends.
4386        cursor.seek(&query_range.end);
4387        let mut range_end = None;
4388        while let Some(region) = cursor.region() {
4389            if region.is_main_buffer {
4390                let mut buffer_end = region.buffer_range.start;
4391                let overshoot = if query_range.end > region.range.start {
4392                    query_range.end - region.range.start
4393                } else {
4394                    <MBD::TextDimension>::default()
4395                };
4396                buffer_end = buffer_end + overshoot;
4397                range_end = Some((region.excerpt.id, buffer_end));
4398                break;
4399            }
4400            cursor.next();
4401        }
4402
4403        cursor.seek(&query_range.start);
4404
4405        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4406            && region.range.start > MBD::default()
4407        {
4408            cursor.prev()
4409        } else if let Some(region) = cursor.region()
4410            && region.is_main_buffer
4411            && region.diff_hunk_status.is_some()
4412        {
4413            cursor.prev();
4414            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4415                cursor.next();
4416            }
4417        }
4418
4419        iter::from_fn(move || {
4420            loop {
4421                let excerpt = cursor.excerpt()?;
4422
4423                // If we have already retrieved metadata for this excerpt, continue to use it.
4424                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4425                    .as_mut()
4426                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4427                {
4428                    Some(metadata)
4429                }
4430                // Otherwise, compute the intersection of the input range with the excerpt's range,
4431                // and retrieve the metadata for the resulting range.
4432                else {
4433                    let region = cursor.region()?;
4434                    let mut buffer_start;
4435                    if region.is_main_buffer {
4436                        buffer_start = region.buffer_range.start;
4437                        if query_range.start > region.range.start {
4438                            let overshoot = query_range.start - region.range.start;
4439                            buffer_start = buffer_start + overshoot;
4440                        }
4441                        buffer_start = buffer_start.min(region.buffer_range.end);
4442                    } else {
4443                        buffer_start = cursor.main_buffer_position()?;
4444                    };
4445                    let mut buffer_end = excerpt
4446                        .range
4447                        .context
4448                        .end
4449                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4450                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4451                        && excerpt.id == end_excerpt_id
4452                    {
4453                        buffer_end = buffer_end.min(end_buffer_offset);
4454                    }
4455
4456                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4457                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4458                    })
4459                };
4460
4461                // Visit each metadata item.
4462                if let Some((metadata_buffer_range, metadata)) =
4463                    metadata_iter.and_then(Iterator::next)
4464                {
4465                    // Find the multibuffer regions that contain the start and end of
4466                    // the metadata item's range.
4467                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4468                        while let Some(region) = cursor.region() {
4469                            if (region.is_main_buffer
4470                                && (region.buffer_range.end >= metadata_buffer_range.start
4471                                    || cursor.is_at_end_of_excerpt()))
4472                                || (!region.is_main_buffer
4473                                    && region.buffer_range.start == metadata_buffer_range.start)
4474                            {
4475                                break;
4476                            }
4477                            cursor.next();
4478                        }
4479                    }
4480                    let start_region = cursor.region()?.clone();
4481                    while let Some(region) = cursor.region() {
4482                        if region.is_main_buffer
4483                            && (region.buffer_range.end > metadata_buffer_range.end
4484                                || cursor.is_at_end_of_excerpt())
4485                        {
4486                            break;
4487                        }
4488                        cursor.next();
4489                    }
4490                    let end_region = cursor.region();
4491
4492                    // Convert the metadata item's range into multibuffer coordinates.
4493                    let mut start_position = start_region.range.start;
4494                    let region_buffer_start = start_region.buffer_range.start;
4495                    if start_region.is_main_buffer
4496                        && metadata_buffer_range.start > region_buffer_start
4497                    {
4498                        start_position =
4499                            start_position + (metadata_buffer_range.start - region_buffer_start);
4500                        start_position = start_position.min(start_region.range.end);
4501                    }
4502
4503                    let mut end_position = self.max_position();
4504                    if let Some(end_region) = &end_region {
4505                        end_position = end_region.range.start;
4506                        debug_assert!(end_region.is_main_buffer);
4507                        let region_buffer_start = end_region.buffer_range.start;
4508                        if metadata_buffer_range.end > region_buffer_start {
4509                            end_position =
4510                                end_position + (metadata_buffer_range.end - region_buffer_start);
4511                        }
4512                        end_position = end_position.min(end_region.range.end);
4513                    }
4514
4515                    if start_position <= query_range.end && end_position >= query_range.start {
4516                        return Some((start_position..end_position, metadata, excerpt));
4517                    }
4518                }
4519                // When there are no more metadata items for this excerpt, move to the next excerpt.
4520                else {
4521                    current_excerpt_metadata.take();
4522                    if let Some((end_excerpt_id, _)) = range_end
4523                        && excerpt.id == end_excerpt_id
4524                    {
4525                        return None;
4526                    }
4527                    cursor.next_excerpt_forwards();
4528                }
4529            }
4530        })
4531    }
4532
4533    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4534        let offset = position.to_offset(self);
4535
4536        let mut cursor = self
4537            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4538            );
4539        cursor.seek(&DimensionPair {
4540            key: offset,
4541            value: None,
4542        });
4543        cursor.seek_to_start_of_current_excerpt();
4544        let excerpt = cursor.excerpt()?;
4545
4546        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4547        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4548        let current_position = self
4549            .anchor_before(offset)
4550            .text_anchor
4551            .to_offset(&excerpt.buffer);
4552
4553        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4554            if diff.is_inverted {
4555                for hunk in diff.hunks_intersecting_base_text_range_rev(
4556                    excerpt_start..excerpt_end,
4557                    diff.original_buffer_snapshot(),
4558                ) {
4559                    if hunk.diff_base_byte_range.end >= current_position {
4560                        continue;
4561                    }
4562                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4563                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4564                    return Some(MultiBufferRow(start.row));
4565                }
4566            } else {
4567                let excerpt_end = excerpt
4568                    .buffer
4569                    .anchor_before(excerpt_end.min(current_position));
4570                for hunk in diff.hunks_intersecting_range_rev(
4571                    excerpt.range.context.start..excerpt_end,
4572                    &excerpt.buffer,
4573                ) {
4574                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4575                    if hunk_end >= current_position {
4576                        continue;
4577                    }
4578                    let start =
4579                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4580                    return Some(MultiBufferRow(start.row));
4581                }
4582            }
4583        }
4584
4585        loop {
4586            cursor.prev_excerpt();
4587            let excerpt = cursor.excerpt()?;
4588
4589            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4590                continue;
4591            };
4592            if diff.is_inverted {
4593                let Some(hunk) = diff
4594                    .hunks_intersecting_base_text_range_rev(
4595                        excerpt.range.context.to_offset(&excerpt.buffer),
4596                        diff.original_buffer_snapshot(),
4597                    )
4598                    .next()
4599                else {
4600                    continue;
4601                };
4602                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4603                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4604                return Some(MultiBufferRow(start.row));
4605            } else {
4606                let Some(hunk) = diff
4607                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4608                    .next()
4609                else {
4610                    continue;
4611                };
4612                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4613                return Some(MultiBufferRow(start.row));
4614            }
4615        }
4616    }
4617
4618    pub fn has_diff_hunks(&self) -> bool {
4619        self.diffs.values().any(|diff| !diff.is_empty())
4620    }
4621
4622    pub fn is_inside_word<T: ToOffset>(
4623        &self,
4624        position: T,
4625        scope_context: Option<CharScopeContext>,
4626    ) -> bool {
4627        let position = position.to_offset(self);
4628        let classifier = self
4629            .char_classifier_at(position)
4630            .scope_context(scope_context);
4631        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4632        let prev_char_kind = self
4633            .reversed_chars_at(position)
4634            .next()
4635            .map(|c| classifier.kind(c));
4636        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4637    }
4638
4639    pub fn surrounding_word<T: ToOffset>(
4640        &self,
4641        start: T,
4642        scope_context: Option<CharScopeContext>,
4643    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4644        let mut start = start.to_offset(self);
4645        let mut end = start;
4646        let mut next_chars = self.chars_at(start).peekable();
4647        let mut prev_chars = self.reversed_chars_at(start).peekable();
4648
4649        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4650
4651        let word_kind = cmp::max(
4652            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4653            next_chars.peek().copied().map(|c| classifier.kind(c)),
4654        );
4655
4656        for ch in prev_chars {
4657            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4658                start -= ch.len_utf8();
4659            } else {
4660                break;
4661            }
4662        }
4663
4664        for ch in next_chars {
4665            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4666                end += ch.len_utf8();
4667            } else {
4668                break;
4669            }
4670        }
4671
4672        (start..end, word_kind)
4673    }
4674
4675    pub fn char_kind_before<T: ToOffset>(
4676        &self,
4677        start: T,
4678        scope_context: Option<CharScopeContext>,
4679    ) -> Option<CharKind> {
4680        let start = start.to_offset(self);
4681        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4682        self.reversed_chars_at(start)
4683            .next()
4684            .map(|ch| classifier.kind(ch))
4685    }
4686
4687    pub fn is_singleton(&self) -> bool {
4688        self.singleton
4689    }
4690
4691    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4692        if self.singleton {
4693            self.excerpts
4694                .iter()
4695                .next()
4696                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4697        } else {
4698            None
4699        }
4700    }
4701
4702    pub fn len(&self) -> MultiBufferOffset {
4703        self.diff_transforms.summary().output.len
4704    }
4705
4706    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4707        MBD::from_summary(&self.text_summary())
4708    }
4709
4710    pub fn is_empty(&self) -> bool {
4711        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4712    }
4713
4714    pub fn widest_line_number(&self) -> u32 {
4715        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4716        self.excerpts.summary().widest_line_number + 1
4717    }
4718
4719    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4720        let range = range.start.to_offset(self)..range.end.to_offset(self);
4721        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4722        excerpts.seek(&range.start);
4723
4724        let mut chunk;
4725        let mut has_trailing_newline;
4726        let excerpt_bytes;
4727        if let Some(region) = excerpts.region() {
4728            let mut bytes = region.buffer.bytes_in_range(
4729                region.buffer_range.start + (range.start - region.range.start)
4730                    ..(region.buffer_range.start + (range.end - region.range.start))
4731                        .min(region.buffer_range.end),
4732            );
4733            chunk = bytes.next().unwrap_or(&[][..]);
4734            excerpt_bytes = Some(bytes);
4735            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4736            if chunk.is_empty() && has_trailing_newline {
4737                chunk = b"\n";
4738                has_trailing_newline = false;
4739            }
4740        } else {
4741            chunk = &[][..];
4742            excerpt_bytes = None;
4743            has_trailing_newline = false;
4744        };
4745
4746        MultiBufferBytes {
4747            range,
4748            cursor: excerpts,
4749            excerpt_bytes,
4750            has_trailing_newline,
4751            chunk,
4752        }
4753    }
4754
4755    pub fn reversed_bytes_in_range<T: ToOffset>(
4756        &self,
4757        range: Range<T>,
4758    ) -> ReversedMultiBufferBytes<'_> {
4759        let range = range.start.to_offset(self)..range.end.to_offset(self);
4760        let mut chunks = self.reversed_chunks_in_range(range.clone());
4761        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4762        ReversedMultiBufferBytes {
4763            range,
4764            chunks,
4765            chunk,
4766        }
4767    }
4768
4769    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4770        let mut cursor = self.cursor::<Point, Point>();
4771        cursor.seek(&Point::new(start_row.0, 0));
4772        let mut result = MultiBufferRows {
4773            point: Point::new(0, 0),
4774            is_empty: self.excerpts.is_empty(),
4775            is_singleton: self.is_singleton(),
4776            cursor,
4777        };
4778        result.seek(start_row);
4779        result
4780    }
4781
4782    pub fn chunks<T: ToOffset>(
4783        &self,
4784        range: Range<T>,
4785        language_aware: bool,
4786    ) -> MultiBufferChunks<'_> {
4787        let mut chunks = MultiBufferChunks {
4788            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4789                ..ExcerptDimension(MultiBufferOffset::ZERO),
4790            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4791            excerpts: self.excerpts.cursor(()),
4792            diff_transforms: self.diff_transforms.cursor(()),
4793            diffs: &self.diffs,
4794            diff_base_chunks: None,
4795            excerpt_chunks: None,
4796            buffer_chunk: None,
4797            language_aware,
4798        };
4799        let range = range.start.to_offset(self)..range.end.to_offset(self);
4800        chunks.seek(range);
4801        chunks
4802    }
4803
4804    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4805        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4806    }
4807
4808    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4809        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4810    }
4811
4812    pub fn clip_offset_utf16(
4813        &self,
4814        offset: MultiBufferOffsetUtf16,
4815        bias: Bias,
4816    ) -> MultiBufferOffsetUtf16 {
4817        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4818    }
4819
4820    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4821        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4822            buffer.clip_point_utf16(Unclipped(point), bias)
4823        })
4824    }
4825
4826    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4827        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4828    }
4829
4830    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4831        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4832    }
4833
4834    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4835        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4836    }
4837
4838    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4839        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4840    }
4841
4842    #[instrument(skip_all)]
4843    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4844        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4845    }
4846
4847    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4848        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4849    }
4850
4851    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4852        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4853    }
4854
4855    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4856        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4857    }
4858
4859    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4860        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4861    }
4862
4863    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4864        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4865    }
4866
4867    fn clip_dimension<MBD, BD>(
4868        &self,
4869        position: MBD,
4870        bias: Bias,
4871        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4872    ) -> MBD
4873    where
4874        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4875        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4876    {
4877        let mut cursor = self.cursor::<MBD, BD>();
4878        cursor.seek(&position);
4879        if let Some(region) = cursor.region() {
4880            if position >= region.range.end {
4881                return region.range.end;
4882            }
4883            let overshoot = position - region.range.start;
4884            let mut buffer_position = region.buffer_range.start;
4885            buffer_position += overshoot;
4886            let clipped_buffer_position =
4887                clip_buffer_position(region.buffer, buffer_position, bias);
4888            let mut position = region.range.start;
4889            position += clipped_buffer_position - region.buffer_range.start;
4890            position
4891        } else {
4892            self.max_position()
4893        }
4894    }
4895
4896    #[instrument(skip_all)]
4897    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4898        &self,
4899        key: MBR1,
4900        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4901    ) -> MBR2
4902    where
4903        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4904        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4905        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4906        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4907    {
4908        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4909        cursor.seek(&DimensionPair { key, value: None });
4910        if let Some(region) = cursor.region() {
4911            if key >= region.range.end.key {
4912                return region.range.end.value.unwrap();
4913            }
4914            let start_key = region.range.start.key;
4915            let start_value = region.range.start.value.unwrap();
4916            let buffer_start_key = region.buffer_range.start.key;
4917            let buffer_start_value = region.buffer_range.start.value.unwrap();
4918            let mut buffer_key = buffer_start_key;
4919            buffer_key += key - start_key;
4920            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4921            let mut result = start_value;
4922            result += buffer_value - buffer_start_value;
4923            result
4924        } else {
4925            self.max_position()
4926        }
4927    }
4928
4929    pub fn point_to_buffer_offset<T: ToOffset>(
4930        &self,
4931        point: T,
4932    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4933        let offset = point.to_offset(self);
4934        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4935        cursor.seek(&offset);
4936        let region = cursor.region()?;
4937        let overshoot = offset - region.range.start;
4938        let buffer_offset = region.buffer_range.start + overshoot;
4939        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4940            && region.has_trailing_newline
4941            && !region.is_main_buffer
4942        {
4943            let main_buffer_position = cursor.main_buffer_position()?;
4944            let buffer_snapshot = &cursor.excerpt()?.buffer;
4945            return Some((buffer_snapshot, main_buffer_position));
4946        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4947            return None;
4948        }
4949        Some((region.buffer, buffer_offset))
4950    }
4951
4952    pub fn point_to_buffer_point(
4953        &self,
4954        point: Point,
4955    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4956        let mut cursor = self.cursor::<Point, Point>();
4957        cursor.seek(&point);
4958        let region = cursor.region()?;
4959        let overshoot = point - region.range.start;
4960        let buffer_point = region.buffer_range.start + overshoot;
4961        let excerpt = cursor.excerpt()?;
4962        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4963            && region.has_trailing_newline
4964            && !region.is_main_buffer
4965        {
4966            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4967        } else if buffer_point > region.buffer.max_point() {
4968            return None;
4969        }
4970        Some((region.buffer, buffer_point, excerpt.id))
4971    }
4972
4973    pub fn suggested_indents(
4974        &self,
4975        rows: impl IntoIterator<Item = u32>,
4976        cx: &App,
4977    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4978        let mut result = BTreeMap::new();
4979        self.suggested_indents_callback(
4980            rows,
4981            &mut |row, indent| {
4982                result.insert(row, indent);
4983                ControlFlow::Continue(())
4984            },
4985            cx,
4986        );
4987        result
4988    }
4989
4990    // move this to be a generator once those are a thing
4991    pub fn suggested_indents_callback(
4992        &self,
4993        rows: impl IntoIterator<Item = u32>,
4994        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4995        cx: &App,
4996    ) {
4997        let mut rows_for_excerpt = Vec::new();
4998        let mut cursor = self.cursor::<Point, Point>();
4999        let mut rows = rows.into_iter().peekable();
5000        let mut prev_row = u32::MAX;
5001        let mut prev_language_indent_size = IndentSize::default();
5002
5003        while let Some(row) = rows.next() {
5004            cursor.seek(&Point::new(row, 0));
5005            let Some(region) = cursor.region() else {
5006                continue;
5007            };
5008
5009            // Retrieve the language and indent size once for each disjoint region being indented.
5010            let single_indent_size = if row.saturating_sub(1) == prev_row {
5011                prev_language_indent_size
5012            } else {
5013                region
5014                    .buffer
5015                    .language_indent_size_at(Point::new(row, 0), cx)
5016            };
5017            prev_language_indent_size = single_indent_size;
5018            prev_row = row;
5019
5020            let start_buffer_row = region.buffer_range.start.row;
5021            let start_multibuffer_row = region.range.start.row;
5022            let end_multibuffer_row = region.range.end.row;
5023
5024            rows_for_excerpt.push(row);
5025            while let Some(next_row) = rows.peek().copied() {
5026                if end_multibuffer_row > next_row {
5027                    rows_for_excerpt.push(next_row);
5028                    rows.next();
5029                } else {
5030                    break;
5031                }
5032            }
5033
5034            let buffer_rows = rows_for_excerpt
5035                .drain(..)
5036                .map(|row| start_buffer_row + row - start_multibuffer_row);
5037            let buffer_indents = region
5038                .buffer
5039                .suggested_indents(buffer_rows, single_indent_size);
5040            for (row, indent) in buffer_indents {
5041                if cb(
5042                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5043                    indent,
5044                )
5045                .is_break()
5046                {
5047                    return;
5048                }
5049            }
5050        }
5051    }
5052
5053    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5054        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5055            let mut size = buffer.indent_size_for_line(range.start.row);
5056            size.len = size
5057                .len
5058                .min(range.end.column)
5059                .saturating_sub(range.start.column);
5060            size
5061        } else {
5062            IndentSize::spaces(0)
5063        }
5064    }
5065
5066    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5067        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5068            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5069        } else {
5070            LineIndent::spaces(0)
5071        }
5072    }
5073
5074    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5075        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5076
5077        if self.language_settings(cx).extend_comment_on_newline
5078            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5079        {
5080            let delimiters = language_scope.line_comment_prefixes();
5081            for delimiter in delimiters {
5082                if *self
5083                    .chars_at(Point::new(row.0, indent.len() as u32))
5084                    .take(delimiter.chars().count())
5085                    .collect::<String>()
5086                    .as_str()
5087                    == **delimiter
5088                {
5089                    indent.push_str(delimiter);
5090                    break;
5091                }
5092            }
5093        }
5094
5095        indent
5096    }
5097
5098    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5099    where
5100        T: ToOffset,
5101    {
5102        for char in self.reversed_chars_at(position) {
5103            if !char.is_whitespace() {
5104                return false;
5105            }
5106            if char == '\n' {
5107                return true;
5108            }
5109        }
5110        true
5111    }
5112
5113    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5114        while row.0 > 0 {
5115            row.0 -= 1;
5116            if !self.is_line_blank(row) {
5117                return Some(row);
5118            }
5119        }
5120        None
5121    }
5122
5123    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5124        if let Some((_, range)) = self.buffer_line_for_row(row) {
5125            range.end.column - range.start.column
5126        } else {
5127            0
5128        }
5129    }
5130
5131    pub fn buffer_line_for_row(
5132        &self,
5133        row: MultiBufferRow,
5134    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5135        let mut cursor = self.cursor::<Point, Point>();
5136        let point = Point::new(row.0, 0);
5137        cursor.seek(&point);
5138        let region = cursor.region()?;
5139        let overshoot = point.min(region.range.end) - region.range.start;
5140        let buffer_point = region.buffer_range.start + overshoot;
5141        if buffer_point.row > region.buffer_range.end.row {
5142            return None;
5143        }
5144        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5145        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5146            .min(region.buffer_range.end);
5147        Some((region.buffer, line_start..line_end))
5148    }
5149
5150    pub fn max_point(&self) -> Point {
5151        self.text_summary().lines
5152    }
5153
5154    pub fn max_row(&self) -> MultiBufferRow {
5155        MultiBufferRow(self.text_summary().lines.row)
5156    }
5157
5158    pub fn text_summary(&self) -> MBTextSummary {
5159        self.diff_transforms.summary().output
5160    }
5161
5162    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5163    where
5164        MBD: MultiBufferDimension + AddAssign,
5165        O: ToOffset,
5166    {
5167        let range = range.start.to_offset(self)..range.end.to_offset(self);
5168        let mut cursor = self
5169            .diff_transforms
5170            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5171        cursor.seek(&range.start, Bias::Right);
5172
5173        let Some(first_transform) = cursor.item() else {
5174            return MBD::from_summary(&MBTextSummary::default());
5175        };
5176
5177        let diff_transform_start = cursor.start().0;
5178        let diff_transform_end = cursor.end().0;
5179        let diff_start = range.start;
5180        let start_overshoot = diff_start - diff_transform_start;
5181        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5182
5183        let mut result = match first_transform {
5184            DiffTransform::BufferContent { .. } => {
5185                let excerpt_start = cursor.start().1 + start_overshoot;
5186                let excerpt_end = cursor.start().1 + end_overshoot;
5187                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5188            }
5189            DiffTransform::DeletedHunk {
5190                buffer_id,
5191                base_text_byte_range,
5192                has_trailing_newline,
5193                ..
5194            } => {
5195                let buffer_start = base_text_byte_range.start + start_overshoot;
5196                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5197                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5198                    panic!("{:?} is in non-existent deleted hunk", range.start)
5199                };
5200
5201                let include_trailing_newline =
5202                    *has_trailing_newline && range.end >= diff_transform_end;
5203                if include_trailing_newline {
5204                    buffer_end -= 1;
5205                }
5206
5207                let mut summary = base_text
5208                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5209
5210                if include_trailing_newline {
5211                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5212                        &TextSummary::newline(),
5213                    ))
5214                }
5215
5216                let mut result = MBD::default();
5217                result.add_text_dim(&summary);
5218                result
5219            }
5220        };
5221        if range.end < diff_transform_end {
5222            return result;
5223        }
5224
5225        cursor.next();
5226        result.add_mb_text_summary(
5227            &cursor
5228                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5229                .0,
5230        );
5231
5232        let Some(last_transform) = cursor.item() else {
5233            return result;
5234        };
5235
5236        let overshoot = range.end - cursor.start().0;
5237        let suffix = match last_transform {
5238            DiffTransform::BufferContent { .. } => {
5239                let end = cursor.start().1 + overshoot;
5240                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5241            }
5242            DiffTransform::DeletedHunk {
5243                base_text_byte_range,
5244                buffer_id,
5245                has_trailing_newline,
5246                ..
5247            } => {
5248                let buffer_end = base_text_byte_range.start + overshoot;
5249                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5250                    panic!("{:?} is in non-existent deleted hunk", range.end)
5251                };
5252
5253                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5254                    base_text_byte_range.start..buffer_end,
5255                );
5256                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5257                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5258                        &TextSummary::from("\n"),
5259                    ))
5260                }
5261
5262                let mut result = MBD::default();
5263                result.add_text_dim(&suffix);
5264                result
5265            }
5266        };
5267
5268        result += suffix;
5269        result
5270    }
5271
5272    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5273    where
5274        MBD: MultiBufferDimension + AddAssign,
5275    {
5276        let mut summary = MBD::default();
5277        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5278        cursor.seek(&range.start, Bias::Right);
5279        if let Some(excerpt) = cursor.item() {
5280            let mut end_before_newline = cursor.end();
5281            if excerpt.has_trailing_newline {
5282                end_before_newline -= 1;
5283            }
5284
5285            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5286            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5287            let end_in_excerpt =
5288                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5289            summary.add_text_dim(
5290                &excerpt
5291                    .buffer
5292                    .text_summary_for_range::<MBD::TextDimension, _>(
5293                        start_in_excerpt..end_in_excerpt,
5294                    ),
5295            );
5296
5297            if range.end > end_before_newline {
5298                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5299            }
5300
5301            cursor.next();
5302        }
5303
5304        if range.end > *cursor.start() {
5305            summary += cursor
5306                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5307                .0;
5308            if let Some(excerpt) = cursor.item() {
5309                range.end = cmp::max(*cursor.start(), range.end);
5310
5311                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5312                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5313                summary.add_text_dim(
5314                    &excerpt
5315                        .buffer
5316                        .text_summary_for_range::<MBD::TextDimension, _>(
5317                            excerpt_start..end_in_excerpt,
5318                        ),
5319                );
5320            }
5321        }
5322
5323        summary
5324    }
5325
5326    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5327    where
5328        MBD: MultiBufferDimension
5329            + Ord
5330            + Sub<Output = MBD::TextDimension>
5331            + Sub<MBD::TextDimension, Output = MBD>
5332            + AddAssign<MBD::TextDimension>
5333            + Add<MBD::TextDimension, Output = MBD>,
5334        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5335    {
5336        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5337        let locator = self.excerpt_locator_for_id(excerpt_id);
5338        let (start, _, mut item) = self
5339            .excerpts
5340            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5341        let mut start = MBD::from_summary(&start.text);
5342        if item.is_none() && excerpt_id == ExcerptId::max() {
5343            item = self.excerpts.last();
5344            if let Some(last_summary) = self.excerpts.last_summary() {
5345                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5346            }
5347        }
5348
5349        if self.diff_transforms.is_empty() {
5350            let excerpt_start_position = ExcerptDimension(start);
5351            if let Some(excerpt) = item {
5352                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5353                    return excerpt_start_position.0;
5354                }
5355                let excerpt_buffer_start = excerpt
5356                    .range
5357                    .context
5358                    .start
5359                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5360                let excerpt_buffer_end = excerpt
5361                    .range
5362                    .context
5363                    .end
5364                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5365                let buffer_summary = anchor
5366                    .text_anchor
5367                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5368                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5369                let mut position = excerpt_start_position;
5370                if summary > excerpt_buffer_start {
5371                    position += summary - excerpt_buffer_start;
5372                }
5373
5374                position.0
5375            } else {
5376                excerpt_start_position.0
5377            }
5378        } else {
5379            let mut diff_transforms_cursor = self
5380                .diff_transforms
5381                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5382            diff_transforms_cursor.next();
5383
5384            let excerpt_start_position = ExcerptDimension(start);
5385            if let Some(excerpt) = item {
5386                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5387                    return self.resolve_summary_for_anchor(
5388                        &Anchor::min(),
5389                        excerpt_start_position,
5390                        &mut diff_transforms_cursor,
5391                    );
5392                }
5393                let excerpt_buffer_start = excerpt
5394                    .range
5395                    .context
5396                    .start
5397                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5398                let excerpt_buffer_end = excerpt
5399                    .range
5400                    .context
5401                    .end
5402                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5403                let buffer_summary = anchor
5404                    .text_anchor
5405                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5406                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5407                let mut position = excerpt_start_position;
5408                if summary > excerpt_buffer_start {
5409                    position += summary - excerpt_buffer_start;
5410                }
5411
5412                if diff_transforms_cursor.start().0 < position {
5413                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5414                }
5415                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5416            } else {
5417                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5418                self.resolve_summary_for_anchor(
5419                    &Anchor::max(),
5420                    excerpt_start_position,
5421                    &mut diff_transforms_cursor,
5422                )
5423            }
5424        }
5425    }
5426
5427    fn resolve_summary_for_anchor<MBD>(
5428        &self,
5429        anchor: &Anchor,
5430        excerpt_position: ExcerptDimension<MBD>,
5431        diff_transforms: &mut Cursor<
5432            DiffTransform,
5433            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5434        >,
5435    ) -> MBD
5436    where
5437        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5438    {
5439        loop {
5440            let transform_end_position = diff_transforms.end().0;
5441            let at_transform_end =
5442                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5443            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5444                diff_transforms.next();
5445                continue;
5446            }
5447
5448            let mut position = diff_transforms.start().1;
5449            match diff_transforms.item() {
5450                Some(DiffTransform::DeletedHunk {
5451                    buffer_id,
5452                    base_text_byte_range,
5453                    ..
5454                }) => {
5455                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5456                        && let Some(base_text) =
5457                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5458                        && diff_base_anchor.is_valid(&base_text)
5459                    {
5460                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5461                        if base_text_offset >= base_text_byte_range.start
5462                            && base_text_offset <= base_text_byte_range.end
5463                        {
5464                            let position_in_hunk = base_text
5465                                .text_summary_for_range::<MBD::TextDimension, _>(
5466                                    base_text_byte_range.start..base_text_offset,
5467                                );
5468                            position.0.add_text_dim(&position_in_hunk);
5469                        } else if at_transform_end {
5470                            diff_transforms.next();
5471                            continue;
5472                        }
5473                    }
5474                }
5475                _ => {
5476                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5477                        diff_transforms.next();
5478                        continue;
5479                    }
5480                    let overshoot = excerpt_position - diff_transforms.start().0;
5481                    position += overshoot;
5482                }
5483            }
5484
5485            return position.0;
5486        }
5487    }
5488
5489    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5490        let mut cursor = self
5491            .excerpts
5492            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5493        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5494
5495        cursor.seek(&Some(locator), Bias::Left);
5496        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5497            cursor.prev();
5498        }
5499
5500        let mut position = cursor.start().1;
5501        if let Some(excerpt) = cursor.item()
5502            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5503        {
5504            let excerpt_buffer_start = excerpt
5505                .buffer
5506                .offset_for_anchor(&excerpt.range.context.start);
5507            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5508            let buffer_position = cmp::min(
5509                excerpt_buffer_end,
5510                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5511            );
5512            if buffer_position > excerpt_buffer_start {
5513                position += buffer_position - excerpt_buffer_start;
5514            }
5515        }
5516        position
5517    }
5518
5519    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5520        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5521            excerpt_id = *replacement;
5522        }
5523        excerpt_id
5524    }
5525
5526    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5527    where
5528        MBD: MultiBufferDimension
5529            + Ord
5530            + Sub<Output = MBD::TextDimension>
5531            + AddAssign<MBD::TextDimension>,
5532        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5533        I: 'a + IntoIterator<Item = &'a Anchor>,
5534    {
5535        let mut anchors = anchors.into_iter().peekable();
5536        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5537        let mut diff_transforms_cursor = self
5538            .diff_transforms
5539            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5540        diff_transforms_cursor.next();
5541
5542        let mut summaries = Vec::new();
5543        while let Some(anchor) = anchors.peek() {
5544            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5545
5546            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5547                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5548            });
5549
5550            let locator = self.excerpt_locator_for_id(excerpt_id);
5551            cursor.seek_forward(locator, Bias::Left);
5552            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5553                cursor.prev();
5554            }
5555
5556            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5557            if let Some(excerpt) = cursor.item() {
5558                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5559                    let position = self.resolve_summary_for_anchor(
5560                        &Anchor::min(),
5561                        excerpt_start_position,
5562                        &mut diff_transforms_cursor,
5563                    );
5564                    summaries.extend(excerpt_anchors.map(|_| position));
5565                    continue;
5566                }
5567                let excerpt_buffer_start = excerpt
5568                    .range
5569                    .context
5570                    .start
5571                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5572                let excerpt_buffer_end = excerpt
5573                    .range
5574                    .context
5575                    .end
5576                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5577                for (buffer_summary, anchor) in excerpt
5578                    .buffer
5579                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5580                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5581                    )
5582                {
5583                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5584                    let mut position = excerpt_start_position;
5585                    if summary > excerpt_buffer_start {
5586                        position += summary - excerpt_buffer_start;
5587                    }
5588
5589                    if diff_transforms_cursor.start().0 < position {
5590                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5591                    }
5592
5593                    summaries.push(self.resolve_summary_for_anchor(
5594                        anchor,
5595                        position,
5596                        &mut diff_transforms_cursor,
5597                    ));
5598                }
5599            } else {
5600                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5601                let position = self.resolve_summary_for_anchor(
5602                    &Anchor::max(),
5603                    excerpt_start_position,
5604                    &mut diff_transforms_cursor,
5605                );
5606                summaries.extend(excerpt_anchors.map(|_| position));
5607            }
5608        }
5609
5610        summaries
5611    }
5612
5613    pub fn dimensions_from_points<'a, MBD>(
5614        &'a self,
5615        points: impl 'a + IntoIterator<Item = Point>,
5616    ) -> impl 'a + Iterator<Item = MBD>
5617    where
5618        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5619    {
5620        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5621        cursor.seek(&DimensionPair {
5622            key: Point::default(),
5623            value: None,
5624        });
5625        let mut points = points.into_iter();
5626        iter::from_fn(move || {
5627            let point = points.next()?;
5628
5629            cursor.seek_forward(&DimensionPair {
5630                key: point,
5631                value: None,
5632            });
5633
5634            if let Some(region) = cursor.region() {
5635                let overshoot = point - region.range.start.key;
5636                let buffer_point = region.buffer_range.start + overshoot;
5637                let mut position = region.range.start.value.unwrap();
5638                position.add_text_dim(
5639                    &region
5640                        .buffer
5641                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5642                );
5643                if point == region.range.end.key && region.has_trailing_newline {
5644                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5645                }
5646                Some(position)
5647            } else {
5648                Some(MBD::from_summary(&self.text_summary()))
5649            }
5650        })
5651    }
5652
5653    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5654    where
5655        I: 'a + IntoIterator<Item = &'a Anchor>,
5656    {
5657        let mut anchors = anchors.into_iter().enumerate().peekable();
5658        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5659        cursor.next();
5660
5661        let mut result = Vec::new();
5662
5663        while let Some((_, anchor)) = anchors.peek() {
5664            let old_excerpt_id = anchor.excerpt_id;
5665
5666            // Find the location where this anchor's excerpt should be.
5667            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5668            cursor.seek_forward(&Some(old_locator), Bias::Left);
5669
5670            let next_excerpt = cursor.item();
5671            let prev_excerpt = cursor.prev_item();
5672
5673            // Process all of the anchors for this excerpt.
5674            while let Some((anchor_ix, &anchor)) =
5675                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5676            {
5677                let mut anchor = anchor;
5678
5679                // Leave min and max anchors unchanged if invalid or
5680                // if the old excerpt still exists at this location
5681                let mut kept_position = next_excerpt
5682                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5683                    || old_excerpt_id == ExcerptId::max()
5684                    || old_excerpt_id == ExcerptId::min();
5685
5686                // If the old excerpt no longer exists at this location, then attempt to
5687                // find an equivalent position for this anchor in an adjacent excerpt.
5688                if !kept_position {
5689                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5690                        if excerpt.contains(&anchor) {
5691                            anchor.excerpt_id = excerpt.id;
5692                            kept_position = true;
5693                            break;
5694                        }
5695                    }
5696                }
5697
5698                // If there's no adjacent excerpt that contains the anchor's position,
5699                // then report that the anchor has lost its position.
5700                if !kept_position {
5701                    anchor = if let Some(excerpt) = next_excerpt {
5702                        let mut text_anchor = excerpt
5703                            .range
5704                            .context
5705                            .start
5706                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5707                        if text_anchor
5708                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5709                            .is_gt()
5710                        {
5711                            text_anchor = excerpt.range.context.end;
5712                        }
5713                        Anchor::in_buffer(excerpt.id, text_anchor)
5714                    } else if let Some(excerpt) = prev_excerpt {
5715                        let mut text_anchor = excerpt
5716                            .range
5717                            .context
5718                            .end
5719                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5720                        if text_anchor
5721                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5722                            .is_lt()
5723                        {
5724                            text_anchor = excerpt.range.context.start;
5725                        }
5726                        Anchor::in_buffer(excerpt.id, text_anchor)
5727                    } else if anchor.text_anchor.bias == Bias::Left {
5728                        Anchor::min()
5729                    } else {
5730                        Anchor::max()
5731                    };
5732                }
5733
5734                result.push((anchor_ix, anchor, kept_position));
5735            }
5736        }
5737        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5738        result
5739    }
5740
5741    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5742        self.anchor_at(position, Bias::Left)
5743    }
5744
5745    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5746        self.anchor_at(position, Bias::Right)
5747    }
5748
5749    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5750        let offset = position.to_offset(self);
5751
5752        // Find the given position in the diff transforms. Determine the corresponding
5753        // offset in the excerpts, and whether the position is within a deleted hunk.
5754        let mut diff_transforms = self
5755            .diff_transforms
5756            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5757        diff_transforms.seek(&offset, Bias::Right);
5758
5759        if offset == diff_transforms.start().0
5760            && bias == Bias::Left
5761            && let Some(prev_item) = diff_transforms.prev_item()
5762            && let DiffTransform::DeletedHunk { .. } = prev_item
5763        {
5764            diff_transforms.prev();
5765        }
5766        let offset_in_transform = offset - diff_transforms.start().0;
5767        let mut excerpt_offset = diff_transforms.start().1;
5768        let mut diff_base_anchor = None;
5769        if let Some(DiffTransform::DeletedHunk {
5770            buffer_id,
5771            base_text_byte_range,
5772            has_trailing_newline,
5773            ..
5774        }) = diff_transforms.item()
5775        {
5776            let diff = self.diffs.get(buffer_id).expect("missing diff");
5777            if offset_in_transform > base_text_byte_range.len() {
5778                debug_assert!(*has_trailing_newline);
5779                bias = Bias::Right;
5780            } else {
5781                diff_base_anchor = Some(
5782                    diff.base_text()
5783                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5784                );
5785                bias = Bias::Left;
5786            }
5787        } else {
5788            excerpt_offset += MultiBufferOffset(offset_in_transform);
5789        };
5790
5791        let mut excerpts = self
5792            .excerpts
5793            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5794        excerpts.seek(&excerpt_offset, Bias::Right);
5795        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5796            excerpts.prev();
5797        }
5798        if let Some(excerpt) = excerpts.item() {
5799            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5800            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5801                overshoot -= 1;
5802                bias = Bias::Right;
5803            }
5804
5805            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5806            let text_anchor =
5807                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5808            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5809            match diff_base_anchor {
5810                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5811                None => anchor,
5812            }
5813        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5814        {
5815            Anchor::min()
5816        } else {
5817            Anchor::max()
5818        }
5819    }
5820
5821    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5822    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5823        let (excerpt, buffer, _) = self.as_singleton()?;
5824        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5825            Some(Anchor::in_buffer(excerpt, text_anchor))
5826        } else {
5827            None
5828        }
5829    }
5830
5831    /// Returns an anchor for the given excerpt and text anchor,
5832    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5833    pub fn anchor_range_in_excerpt(
5834        &self,
5835        excerpt_id: ExcerptId,
5836        text_anchor: Range<text::Anchor>,
5837    ) -> Option<Range<Anchor>> {
5838        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5839
5840        Some(
5841            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5842                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5843        )
5844    }
5845
5846    /// Returns an anchor for the given excerpt and text anchor,
5847    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5848    pub fn anchor_in_excerpt(
5849        &self,
5850        excerpt_id: ExcerptId,
5851        text_anchor: text::Anchor,
5852    ) -> Option<Anchor> {
5853        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5854        Self::anchor_in_excerpt_(excerpt, text_anchor)
5855    }
5856
5857    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5858    pub fn anchors_in_excerpt(
5859        &self,
5860        excerpt_id: ExcerptId,
5861        text_anchors: impl IntoIterator<Item = text::Anchor>,
5862    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5863        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5864        Some(
5865            text_anchors
5866                .into_iter()
5867                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5868        )
5869    }
5870
5871    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5872        match text_anchor.buffer_id {
5873            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5874            Some(_) => return None,
5875            None if text_anchor.is_max() || text_anchor.is_min() => {
5876                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5877            }
5878            None => return None,
5879        }
5880
5881        let context = &excerpt.range.context;
5882        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5883            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5884        {
5885            return None;
5886        }
5887
5888        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5889    }
5890
5891    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5892        Some(self.excerpt(excerpt_id)?.range.context.clone())
5893    }
5894
5895    pub fn excerpt_range_for_excerpt(
5896        &self,
5897        excerpt_id: ExcerptId,
5898    ) -> Option<ExcerptRange<text::Anchor>> {
5899        Some(self.excerpt(excerpt_id)?.range.clone())
5900    }
5901
5902    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5903        if anchor.is_min() || anchor.is_max() {
5904            // todo(lw): should be `!self.is_empty()`
5905            true
5906        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5907            excerpt.buffer.can_resolve(&anchor.text_anchor)
5908        } else {
5909            false
5910        }
5911    }
5912
5913    pub fn excerpts(
5914        &self,
5915    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5916        self.excerpts
5917            .iter()
5918            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5919    }
5920
5921    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5922    where
5923        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5924        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5925    {
5926        let excerpts = self.excerpts.cursor(());
5927        let diff_transforms = self.diff_transforms.cursor(());
5928        MultiBufferCursor {
5929            excerpts,
5930            diff_transforms,
5931            diffs: &self.diffs,
5932            cached_region: OnceCell::new(),
5933        }
5934    }
5935
5936    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5937        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5938        let mut excerpts = self
5939            .excerpts
5940            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5941        excerpts.seek(&Some(start_locator), Bias::Left);
5942        excerpts.prev();
5943
5944        let mut diff_transforms = self
5945            .diff_transforms
5946            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5947        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5948        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5949            diff_transforms.next();
5950        }
5951
5952        let excerpt = excerpts.item()?;
5953        Some(MultiBufferExcerpt {
5954            excerpt,
5955            offset: diff_transforms.start().output_dimension.0,
5956            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5957            excerpt_offset: excerpts.start().1,
5958            diff_transforms,
5959        })
5960    }
5961
5962    pub fn excerpt_boundaries_in_range<R, T>(
5963        &self,
5964        range: R,
5965    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5966    where
5967        R: RangeBounds<T>,
5968        T: ToOffset,
5969    {
5970        let start_offset;
5971        let start = match range.start_bound() {
5972            Bound::Included(start) => {
5973                start_offset = start.to_offset(self);
5974                Bound::Included(start_offset)
5975            }
5976            Bound::Excluded(_) => {
5977                panic!("not supported")
5978            }
5979            Bound::Unbounded => {
5980                start_offset = MultiBufferOffset::ZERO;
5981                Bound::Unbounded
5982            }
5983        };
5984        let end = match range.end_bound() {
5985            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5986            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5987            Bound::Unbounded => Bound::Unbounded,
5988        };
5989        let bounds = (start, end);
5990        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5991        cursor.seek(&DimensionPair {
5992            key: start_offset,
5993            value: None,
5994        });
5995
5996        if cursor
5997            .fetch_excerpt_with_range()
5998            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5999        {
6000            cursor.prev_excerpt();
6001        } else {
6002            cursor.seek_to_start_of_current_excerpt();
6003        }
6004        let mut prev_region = cursor
6005            .fetch_excerpt_with_range()
6006            .map(|(excerpt, _)| excerpt);
6007
6008        cursor.next_excerpt_forwards();
6009
6010        iter::from_fn(move || {
6011            loop {
6012                if self.singleton {
6013                    return None;
6014                }
6015
6016                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6017                cursor.next_excerpt_forwards();
6018                if !bounds.contains(&next_range.start.key) {
6019                    prev_region = Some(next_excerpt);
6020                    continue;
6021                }
6022
6023                let next_region_start = next_range.start.value.unwrap();
6024                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6025                    range.start.value.unwrap()
6026                } else {
6027                    self.max_point()
6028                };
6029
6030                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6031                    id: region.id,
6032                    buffer: region.buffer.clone(),
6033                    buffer_id: region.buffer_id,
6034                    range: region.range.clone(),
6035                    end_row: MultiBufferRow(next_region_start.row),
6036                });
6037
6038                let next = ExcerptInfo {
6039                    id: next_excerpt.id,
6040                    buffer: next_excerpt.buffer.clone(),
6041                    buffer_id: next_excerpt.buffer_id,
6042                    range: next_excerpt.range.clone(),
6043                    end_row: if next_excerpt.has_trailing_newline {
6044                        MultiBufferRow(next_region_end.row - 1)
6045                    } else {
6046                        MultiBufferRow(next_region_end.row)
6047                    },
6048                };
6049
6050                let row = MultiBufferRow(next_region_start.row);
6051
6052                prev_region = Some(next_excerpt);
6053
6054                return Some(ExcerptBoundary { row, prev, next });
6055            }
6056        })
6057    }
6058
6059    pub fn edit_count(&self) -> usize {
6060        self.edit_count
6061    }
6062
6063    pub fn non_text_state_update_count(&self) -> usize {
6064        self.non_text_state_update_count
6065    }
6066
6067    /// Returns the smallest enclosing bracket ranges containing the given range or
6068    /// None if no brackets contain range or the range is not contained in a single
6069    /// excerpt
6070    ///
6071    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6072    #[ztracing::instrument(skip_all)]
6073    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6074        &self,
6075        range: Range<T>,
6076        range_filter: Option<
6077            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6078        >,
6079    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6080        let range = range.start.to_offset(self)..range.end.to_offset(self);
6081        let mut excerpt = self.excerpt_containing(range.clone())?;
6082        let buffer = excerpt.buffer();
6083        let excerpt_buffer_range = excerpt.buffer_range();
6084
6085        // Filter to ranges contained in the excerpt
6086        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6087            excerpt_buffer_range.contains(&BufferOffset(open.start))
6088                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6089                && range_filter.is_none_or(|filter| {
6090                    filter(
6091                        buffer,
6092                        BufferOffset(open.start)..BufferOffset(close.end),
6093                        BufferOffset(close.start)..BufferOffset(close.end),
6094                    )
6095                })
6096        };
6097
6098        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6099            excerpt.map_range_to_buffer(range),
6100            Some(&range_filter),
6101        )?;
6102
6103        Some((
6104            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6105            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6106        ))
6107    }
6108
6109    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6110    /// not contained in a single excerpt
6111    pub fn enclosing_bracket_ranges<T: ToOffset>(
6112        &self,
6113        range: Range<T>,
6114    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6115    {
6116        let range = range.start.to_offset(self)..range.end.to_offset(self);
6117        let mut excerpt = self.excerpt_containing(range.clone())?;
6118
6119        Some(
6120            excerpt
6121                .buffer()
6122                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6123                .filter_map(move |pair| {
6124                    let open_range =
6125                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6126                    let close_range =
6127                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6128                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6129                        Some((
6130                            excerpt.map_range_from_buffer(open_range),
6131                            excerpt.map_range_from_buffer(close_range),
6132                        ))
6133                    } else {
6134                        None
6135                    }
6136                }),
6137        )
6138    }
6139
6140    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6141    /// not contained in a single excerpt
6142    pub fn text_object_ranges<T: ToOffset>(
6143        &self,
6144        range: Range<T>,
6145        options: TreeSitterOptions,
6146    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6147        let range = range.start.to_offset(self)..range.end.to_offset(self);
6148        self.excerpt_containing(range.clone())
6149            .map(|mut excerpt| {
6150                excerpt
6151                    .buffer()
6152                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6153                    .filter_map(move |(range, text_object)| {
6154                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6155                        if excerpt.contains_buffer_range(range.clone()) {
6156                            Some((excerpt.map_range_from_buffer(range), text_object))
6157                        } else {
6158                            None
6159                        }
6160                    })
6161            })
6162            .into_iter()
6163            .flatten()
6164    }
6165
6166    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6167    /// not contained in a single excerpt
6168    pub fn bracket_ranges<T: ToOffset>(
6169        &self,
6170        range: Range<T>,
6171    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6172    {
6173        let range = range.start.to_offset(self)..range.end.to_offset(self);
6174        let mut excerpt = self.excerpt_containing(range.clone())?;
6175        Some(
6176            excerpt
6177                .buffer()
6178                .bracket_ranges(excerpt.map_range_to_buffer(range))
6179                .filter_map(move |pair| {
6180                    let open_range =
6181                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6182                    let close_range =
6183                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6184                    excerpt
6185                        .contains_buffer_range(open_range.start..close_range.end)
6186                        .then(|| BracketMatch {
6187                            open_range: excerpt.map_range_from_buffer(open_range),
6188                            close_range: excerpt.map_range_from_buffer(close_range),
6189                            color_index: pair.color_index,
6190                            newline_only: pair.newline_only,
6191                            syntax_layer_depth: pair.syntax_layer_depth,
6192                        })
6193                })
6194                .map(BracketMatch::bracket_ranges),
6195        )
6196    }
6197
6198    pub fn redacted_ranges<'a, T: ToOffset>(
6199        &'a self,
6200        range: Range<T>,
6201        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6202    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6203        let range = range.start.to_offset(self)..range.end.to_offset(self);
6204        self.lift_buffer_metadata(range, move |buffer, range| {
6205            if redaction_enabled(buffer.file()) {
6206                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6207            } else {
6208                None
6209            }
6210        })
6211        .map(|(range, _, _)| range)
6212    }
6213
6214    pub fn runnable_ranges(
6215        &self,
6216        range: Range<Anchor>,
6217    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6218        let range = range.start.to_offset(self)..range.end.to_offset(self);
6219        self.lift_buffer_metadata(range, move |buffer, range| {
6220            Some(
6221                buffer
6222                    .runnable_ranges(range.clone())
6223                    .filter(move |runnable| {
6224                        runnable.run_range.start >= range.start
6225                            && runnable.run_range.end < range.end
6226                    })
6227                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6228            )
6229        })
6230        .map(|(run_range, runnable, _)| (run_range, runnable))
6231    }
6232
6233    pub fn line_indents(
6234        &self,
6235        start_row: MultiBufferRow,
6236        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6237    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6238        let max_point = self.max_point();
6239        let mut cursor = self.cursor::<Point, Point>();
6240        cursor.seek(&Point::new(start_row.0, 0));
6241        iter::from_fn(move || {
6242            let mut region = cursor.region()?;
6243            while !buffer_filter(&region.excerpt.buffer) {
6244                cursor.next();
6245                region = cursor.region()?;
6246            }
6247            let region = cursor.region()?;
6248            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6249            let buffer_start_row =
6250                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6251
6252            let buffer_end_row = if region.is_main_buffer
6253                && (region.has_trailing_newline || region.range.end == max_point)
6254            {
6255                region.buffer_range.end.row
6256            } else {
6257                region.buffer_range.end.row.saturating_sub(1)
6258            };
6259
6260            let line_indents = region
6261                .buffer
6262                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6263            let region_buffer_row = region.buffer_range.start.row;
6264            let region_row = region.range.start.row;
6265            let region_buffer = &region.excerpt.buffer;
6266            cursor.next();
6267            Some(line_indents.map(move |(buffer_row, indent)| {
6268                let row = region_row + (buffer_row - region_buffer_row);
6269                (MultiBufferRow(row), indent, region_buffer.as_ref())
6270            }))
6271        })
6272        .flatten()
6273    }
6274
6275    pub fn reversed_line_indents(
6276        &self,
6277        end_row: MultiBufferRow,
6278        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6279    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6280        let max_point = self.max_point();
6281        let mut cursor = self.cursor::<Point, Point>();
6282        cursor.seek(&Point::new(end_row.0, 0));
6283        iter::from_fn(move || {
6284            let mut region = cursor.region()?;
6285            while !buffer_filter(&region.excerpt.buffer) {
6286                cursor.prev();
6287                region = cursor.region()?;
6288            }
6289            let region = cursor.region()?;
6290
6291            let buffer_start_row = region.buffer_range.start.row;
6292            let buffer_end_row = if region.is_main_buffer
6293                && (region.has_trailing_newline || region.range.end == max_point)
6294            {
6295                region.buffer_range.end.row + 1
6296            } else {
6297                region.buffer_range.end.row
6298            };
6299
6300            let overshoot = end_row.0 - region.range.start.row;
6301            let buffer_end_row =
6302                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6303
6304            let line_indents = region
6305                .buffer
6306                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6307            let region_buffer_row = region.buffer_range.start.row;
6308            let region_row = region.range.start.row;
6309            let region_buffer = &region.excerpt.buffer;
6310            cursor.prev();
6311            Some(line_indents.map(move |(buffer_row, indent)| {
6312                let row = region_row + (buffer_row - region_buffer_row);
6313                (MultiBufferRow(row), indent, region_buffer.as_ref())
6314            }))
6315        })
6316        .flatten()
6317    }
6318
6319    pub async fn enclosing_indent(
6320        &self,
6321        mut target_row: MultiBufferRow,
6322    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6323        let max_row = MultiBufferRow(self.max_point().row);
6324        if target_row >= max_row {
6325            return None;
6326        }
6327
6328        let mut target_indent = self.line_indent_for_row(target_row);
6329
6330        // If the current row is at the start of an indented block, we want to return this
6331        // block as the enclosing indent.
6332        if !target_indent.is_line_empty() && target_row < max_row {
6333            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6334            if !next_line_indent.is_line_empty()
6335                && target_indent.raw_len() < next_line_indent.raw_len()
6336            {
6337                target_indent = next_line_indent;
6338                target_row.0 += 1;
6339            }
6340        }
6341
6342        const SEARCH_ROW_LIMIT: u32 = 25000;
6343        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6344        const YIELD_INTERVAL: u32 = 100;
6345
6346        let mut accessed_row_counter = 0;
6347
6348        // If there is a blank line at the current row, search for the next non indented lines
6349        if target_indent.is_line_empty() {
6350            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6351            let end =
6352                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6353
6354            let mut non_empty_line_above = None;
6355            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6356                if row < start {
6357                    break;
6358                }
6359                accessed_row_counter += 1;
6360                if accessed_row_counter == YIELD_INTERVAL {
6361                    accessed_row_counter = 0;
6362                    yield_now().await;
6363                }
6364                if !indent.is_line_empty() {
6365                    non_empty_line_above = Some((row, indent));
6366                    break;
6367                }
6368            }
6369
6370            let mut non_empty_line_below = None;
6371            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6372                if row > end {
6373                    break;
6374                }
6375                accessed_row_counter += 1;
6376                if accessed_row_counter == YIELD_INTERVAL {
6377                    accessed_row_counter = 0;
6378                    yield_now().await;
6379                }
6380                if !indent.is_line_empty() {
6381                    non_empty_line_below = Some((row, indent));
6382                    break;
6383                }
6384            }
6385
6386            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6387                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6388                    if above_indent.raw_len() >= below_indent.raw_len() {
6389                        (above_row, above_indent)
6390                    } else {
6391                        (below_row, below_indent)
6392                    }
6393                }
6394                (Some(above), None) => above,
6395                (None, Some(below)) => below,
6396                _ => return None,
6397            };
6398
6399            target_indent = indent;
6400            target_row = row;
6401        }
6402
6403        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6404        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6405
6406        let mut start_indent = None;
6407        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6408            if row < start {
6409                break;
6410            }
6411            accessed_row_counter += 1;
6412            if accessed_row_counter == YIELD_INTERVAL {
6413                accessed_row_counter = 0;
6414                yield_now().await;
6415            }
6416            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6417                start_indent = Some((row, indent));
6418                break;
6419            }
6420        }
6421        let (start_row, start_indent_size) = start_indent?;
6422
6423        let mut end_indent = (end, None);
6424        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6425            if row > end {
6426                break;
6427            }
6428            accessed_row_counter += 1;
6429            if accessed_row_counter == YIELD_INTERVAL {
6430                accessed_row_counter = 0;
6431                yield_now().await;
6432            }
6433            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6434                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6435                break;
6436            }
6437        }
6438        let (end_row, end_indent_size) = end_indent;
6439
6440        let indent = if let Some(end_indent_size) = end_indent_size {
6441            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6442                start_indent_size
6443            } else {
6444                end_indent_size
6445            }
6446        } else {
6447            start_indent_size
6448        };
6449
6450        Some((start_row..end_row, indent))
6451    }
6452
6453    pub fn indent_guides_in_range<T: ToPoint>(
6454        &self,
6455        range: Range<T>,
6456        ignore_disabled_for_language: bool,
6457        cx: &App,
6458    ) -> impl Iterator<Item = IndentGuide> {
6459        let range = range.start.to_point(self)..range.end.to_point(self);
6460        let start_row = MultiBufferRow(range.start.row);
6461        let end_row = MultiBufferRow(range.end.row);
6462
6463        let mut row_indents = self.line_indents(start_row, |buffer| {
6464            let settings =
6465                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6466            settings.indent_guides.enabled || ignore_disabled_for_language
6467        });
6468
6469        let mut result = Vec::new();
6470        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6471
6472        let mut prev_settings = None;
6473        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6474            if first_row > end_row {
6475                break;
6476            }
6477            let current_depth = indent_stack.len() as u32;
6478
6479            // Avoid retrieving the language settings repeatedly for every buffer row.
6480            if let Some((prev_buffer_id, _)) = &prev_settings
6481                && prev_buffer_id != &buffer.remote_id()
6482            {
6483                prev_settings.take();
6484            }
6485            let settings = &prev_settings
6486                .get_or_insert_with(|| {
6487                    (
6488                        buffer.remote_id(),
6489                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6490                    )
6491                })
6492                .1;
6493            let tab_size = settings.tab_size.get();
6494
6495            // When encountering empty, continue until found useful line indent
6496            // then add to the indent stack with the depth found
6497            let mut found_indent = false;
6498            let mut last_row = first_row;
6499            if line_indent.is_line_blank() {
6500                while !found_indent {
6501                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6502                        break;
6503                    };
6504                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6505                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6506                        break;
6507                    }
6508
6509                    if new_line_indent.is_line_blank() {
6510                        continue;
6511                    }
6512                    last_row = target_row.min(end_row);
6513                    line_indent = new_line_indent;
6514                    found_indent = true;
6515                    break;
6516                }
6517            } else {
6518                found_indent = true
6519            }
6520
6521            let depth = if found_indent {
6522                line_indent.len(tab_size) / tab_size
6523            } else {
6524                0
6525            };
6526
6527            match depth.cmp(&current_depth) {
6528                cmp::Ordering::Less => {
6529                    for _ in 0..(current_depth - depth) {
6530                        let mut indent = indent_stack.pop().unwrap();
6531                        if last_row != first_row {
6532                            // In this case, we landed on an empty row, had to seek forward,
6533                            // and discovered that the indent we where on is ending.
6534                            // This means that the last display row must
6535                            // be on line that ends this indent range, so we
6536                            // should display the range up to the first non-empty line
6537                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6538                        }
6539
6540                        result.push(indent)
6541                    }
6542                }
6543                cmp::Ordering::Greater => {
6544                    for next_depth in current_depth..depth {
6545                        indent_stack.push(IndentGuide {
6546                            buffer_id: buffer.remote_id(),
6547                            start_row: first_row,
6548                            end_row: last_row,
6549                            depth: next_depth,
6550                            tab_size,
6551                            settings: settings.indent_guides.clone(),
6552                        });
6553                    }
6554                }
6555                _ => {}
6556            }
6557
6558            for indent in indent_stack.iter_mut() {
6559                indent.end_row = last_row;
6560            }
6561        }
6562
6563        result.extend(indent_stack);
6564        result.into_iter()
6565    }
6566
6567    pub fn trailing_excerpt_update_count(&self) -> usize {
6568        self.trailing_excerpt_update_count
6569    }
6570
6571    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6572        self.point_to_buffer_offset(point)
6573            .and_then(|(buffer, _)| buffer.file())
6574    }
6575
6576    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6577        self.point_to_buffer_offset(offset)
6578            .and_then(|(buffer, offset)| buffer.language_at(offset))
6579    }
6580
6581    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6582        self.excerpts
6583            .first()
6584            .map(|excerpt| &excerpt.buffer)
6585            .map(|buffer| {
6586                language_settings(
6587                    buffer.language().map(|language| language.name()),
6588                    buffer.file(),
6589                    cx,
6590                )
6591            })
6592            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6593    }
6594
6595    pub fn language_settings_at<'a, T: ToOffset>(
6596        &'a self,
6597        point: T,
6598        cx: &'a App,
6599    ) -> Cow<'a, LanguageSettings> {
6600        let mut language = None;
6601        let mut file = None;
6602        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6603            language = buffer.language_at(offset);
6604            file = buffer.file();
6605        }
6606        language_settings(language.map(|l| l.name()), file, cx)
6607    }
6608
6609    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6610        self.point_to_buffer_offset(point)
6611            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6612    }
6613
6614    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6615        self.point_to_buffer_offset(point)
6616            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6617            .unwrap_or_default()
6618    }
6619
6620    pub fn language_indent_size_at<T: ToOffset>(
6621        &self,
6622        position: T,
6623        cx: &App,
6624    ) -> Option<IndentSize> {
6625        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6626        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6627    }
6628
6629    pub fn is_dirty(&self) -> bool {
6630        self.is_dirty
6631    }
6632
6633    pub fn has_deleted_file(&self) -> bool {
6634        self.has_deleted_file
6635    }
6636
6637    pub fn has_conflict(&self) -> bool {
6638        self.has_conflict
6639    }
6640
6641    pub fn has_diagnostics(&self) -> bool {
6642        self.excerpts
6643            .iter()
6644            .any(|excerpt| excerpt.buffer.has_diagnostics())
6645    }
6646
6647    pub fn diagnostic_group(
6648        &self,
6649        buffer_id: BufferId,
6650        group_id: usize,
6651    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6652        self.lift_buffer_metadata::<Point, _, _>(
6653            Point::zero()..self.max_point(),
6654            move |buffer, range| {
6655                if buffer.remote_id() != buffer_id {
6656                    return None;
6657                };
6658                Some(
6659                    buffer
6660                        .diagnostics_in_range(range, false)
6661                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6662                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6663                )
6664            },
6665        )
6666        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6667    }
6668
6669    pub fn diagnostics_in_range<'a, MBD>(
6670        &'a self,
6671        range: Range<MBD>,
6672    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6673    where
6674        MBD::TextDimension: 'a
6675            + text::ToOffset
6676            + text::FromAnchor
6677            + Sub<Output = MBD::TextDimension>
6678            + fmt::Debug
6679            + ops::Add<Output = MBD::TextDimension>
6680            + ops::AddAssign
6681            + Ord,
6682        MBD: MultiBufferDimension
6683            + Ord
6684            + Sub<Output = MBD::TextDimension>
6685            + ops::Add<MBD::TextDimension, Output = MBD>
6686            + ops::AddAssign<MBD::TextDimension>
6687            + 'a,
6688    {
6689        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6690            Some(
6691                buffer
6692                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6693                    .map(|entry| (entry.range, entry.diagnostic)),
6694            )
6695        })
6696        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6697    }
6698
6699    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6700        &'a self,
6701        range: Range<MBD>,
6702    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6703    where
6704        MBD: MultiBufferDimension
6705            + Ord
6706            + Sub<Output = MBD::TextDimension>
6707            + ops::Add<MBD::TextDimension, Output = MBD>
6708            + ops::AddAssign<MBD::TextDimension>,
6709        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6710            + ops::Add<Output = MBD::TextDimension>
6711            + text::ToOffset
6712            + text::FromAnchor
6713            + AddAssign<MBD::TextDimension>
6714            + Ord,
6715    {
6716        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6717            Some(
6718                buffer
6719                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6720                    .map(|entry| (entry.range, entry.diagnostic)),
6721            )
6722        })
6723        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6724    }
6725
6726    pub fn syntax_ancestor<T: ToOffset>(
6727        &self,
6728        range: Range<T>,
6729    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6730        let range = range.start.to_offset(self)..range.end.to_offset(self);
6731        let mut excerpt = self.excerpt_containing(range.clone())?;
6732        let node = excerpt
6733            .buffer()
6734            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6735        let node_range = node.byte_range();
6736        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6737        if !excerpt.contains_buffer_range(node_range.clone()) {
6738            return None;
6739        };
6740        Some((node, excerpt.map_range_from_buffer(node_range)))
6741    }
6742
6743    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6744        let (excerpt_id, _, buffer) = self.as_singleton()?;
6745        let outline = buffer.outline(theme);
6746        Some(Outline::new(
6747            outline
6748                .items
6749                .into_iter()
6750                .flat_map(|item| {
6751                    Some(OutlineItem {
6752                        depth: item.depth,
6753                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6754                        source_range_for_text: self
6755                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6756                        text: item.text,
6757                        highlight_ranges: item.highlight_ranges,
6758                        name_ranges: item.name_ranges,
6759                        body_range: item.body_range.and_then(|body_range| {
6760                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6761                        }),
6762                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6763                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6764                        }),
6765                    })
6766                })
6767                .collect(),
6768        ))
6769    }
6770
6771    pub fn symbols_containing<T: ToOffset>(
6772        &self,
6773        offset: T,
6774        theme: Option<&SyntaxTheme>,
6775    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6776        let anchor = self.anchor_before(offset);
6777        let excerpt @ &Excerpt {
6778            id: excerpt_id,
6779            buffer_id,
6780            ref buffer,
6781            ..
6782        } = self.excerpt(anchor.excerpt_id)?;
6783        if cfg!(debug_assertions) {
6784            match anchor.text_anchor.buffer_id {
6785                // we clearly are hitting this according to sentry, but in what situations can this occur?
6786                Some(anchor_buffer_id) => {
6787                    assert_eq!(
6788                        anchor_buffer_id, buffer_id,
6789                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6790                    )
6791                }
6792                None => assert!(anchor.is_max()),
6793            }
6794        };
6795        Some((
6796            buffer_id,
6797            buffer
6798                .symbols_containing(anchor.text_anchor, theme)
6799                .into_iter()
6800                .flat_map(|item| {
6801                    Some(OutlineItem {
6802                        depth: item.depth,
6803                        source_range_for_text: Anchor::range_in_buffer(
6804                            excerpt_id,
6805                            item.source_range_for_text,
6806                        ),
6807                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6808                        text: item.text,
6809                        highlight_ranges: item.highlight_ranges,
6810                        name_ranges: item.name_ranges,
6811                        body_range: item
6812                            .body_range
6813                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6814                        annotation_range: item
6815                            .annotation_range
6816                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6817                    })
6818                })
6819                .collect(),
6820        ))
6821    }
6822
6823    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6824        if id == ExcerptId::min() {
6825            Locator::min_ref()
6826        } else if id == ExcerptId::max() {
6827            Locator::max_ref()
6828        } else {
6829            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6830            if let Some(entry) = item
6831                && entry.id == id
6832            {
6833                return &entry.locator;
6834            }
6835            panic!("invalid excerpt id {id:?}")
6836        }
6837    }
6838
6839    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6840    fn excerpt_locators_for_ids(
6841        &self,
6842        ids: impl IntoIterator<Item = ExcerptId>,
6843    ) -> SmallVec<[Locator; 1]> {
6844        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6845        sorted_ids.sort_unstable();
6846        sorted_ids.dedup();
6847        let mut locators = SmallVec::new();
6848
6849        while sorted_ids.last() == Some(&ExcerptId::max()) {
6850            sorted_ids.pop();
6851            locators.push(Locator::max());
6852        }
6853
6854        let mut sorted_ids = sorted_ids.into_iter().peekable();
6855        locators.extend(
6856            sorted_ids
6857                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6858                .map(|_| Locator::min()),
6859        );
6860
6861        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6862        for id in sorted_ids {
6863            if cursor.seek_forward(&id, Bias::Left) {
6864                locators.push(cursor.item().unwrap().locator.clone());
6865            } else {
6866                panic!("invalid excerpt id {:?}", id);
6867            }
6868        }
6869
6870        locators.sort_unstable();
6871        locators
6872    }
6873
6874    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6875        Some(self.excerpt(excerpt_id)?.buffer_id)
6876    }
6877
6878    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6879        Some(&self.excerpt(excerpt_id)?.buffer)
6880    }
6881
6882    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6883        let mut cursor = self
6884            .excerpts
6885            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6886        let locator = self.excerpt_locator_for_id(excerpt_id);
6887        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6888        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6889            sought_exact = true;
6890            cursor.prev();
6891        } else if excerpt_id == ExcerptId::min() {
6892            sought_exact = true;
6893        }
6894        if sought_exact {
6895            let start = cursor.start().1;
6896            let end = cursor.end().1;
6897            let mut diff_transforms = self
6898                .diff_transforms
6899                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6900            diff_transforms.seek(&start, Bias::Left);
6901            let overshoot = start - diff_transforms.start().0;
6902            let start = diff_transforms.start().1 + overshoot;
6903            diff_transforms.seek(&end, Bias::Right);
6904            let overshoot = end - diff_transforms.start().0;
6905            let end = diff_transforms.start().1 + overshoot;
6906            Some(start.0..end.0)
6907        } else {
6908            None
6909        }
6910    }
6911
6912    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6913    /// to have the latest excerpt id for the one passed in and will also remap
6914    /// `ExcerptId::max()` to the corresponding excertp ID.
6915    ///
6916    /// Callers of this function should generally use the resulting excerpt's `id` field
6917    /// afterwards.
6918    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6919        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6920        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6921        let locator = self.excerpt_locator_for_id(excerpt_id);
6922        cursor.seek(&Some(locator), Bias::Left);
6923        if let Some(excerpt) = cursor.item()
6924            && excerpt.id == excerpt_id
6925        {
6926            return Some(excerpt);
6927        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6928            cursor.prev();
6929            return cursor.item();
6930        }
6931        None
6932    }
6933
6934    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6935    pub fn excerpt_containing<T: ToOffset>(
6936        &self,
6937        range: Range<T>,
6938    ) -> Option<MultiBufferExcerpt<'_>> {
6939        let range = range.start.to_offset(self)..range.end.to_offset(self);
6940        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6941        cursor.seek(&range.start);
6942
6943        let start_excerpt = cursor.excerpt()?;
6944        if range.end != range.start {
6945            cursor.seek_forward(&range.end);
6946            if cursor.excerpt()?.id != start_excerpt.id {
6947                return None;
6948            }
6949        }
6950
6951        cursor.seek_to_start_of_current_excerpt();
6952        let region = cursor.region()?;
6953        let offset = region.range.start;
6954        let buffer_offset = start_excerpt.buffer_start_offset();
6955        let excerpt_offset = *cursor.excerpts.start();
6956        Some(MultiBufferExcerpt {
6957            diff_transforms: cursor.diff_transforms,
6958            excerpt: start_excerpt,
6959            offset,
6960            buffer_offset,
6961            excerpt_offset,
6962        })
6963    }
6964
6965    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6966        if let Some(id) = anchor.text_anchor.buffer_id {
6967            return Some(id);
6968        }
6969        let excerpt = self.excerpt_containing(anchor..anchor)?;
6970        Some(excerpt.buffer_id())
6971    }
6972
6973    pub fn selections_in_range<'a>(
6974        &'a self,
6975        range: &'a Range<Anchor>,
6976        include_local: bool,
6977    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6978        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6979        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6980        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6981        cursor.seek(start_locator, Bias::Left);
6982        cursor
6983            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6984            .flat_map(move |excerpt| {
6985                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6986                if excerpt.id == range.start.excerpt_id {
6987                    query_range.start = range.start.text_anchor;
6988                }
6989                if excerpt.id == range.end.excerpt_id {
6990                    query_range.end = range.end.text_anchor;
6991                }
6992
6993                excerpt
6994                    .buffer
6995                    .selections_in_range(query_range, include_local)
6996                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6997                        selections.map(move |selection| {
6998                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6999                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7000                            if range.start.cmp(&start, self).is_gt() {
7001                                start = range.start;
7002                            }
7003                            if range.end.cmp(&end, self).is_lt() {
7004                                end = range.end;
7005                            }
7006
7007                            (
7008                                replica_id,
7009                                line_mode,
7010                                cursor_shape,
7011                                Selection {
7012                                    id: selection.id,
7013                                    start,
7014                                    end,
7015                                    reversed: selection.reversed,
7016                                    goal: selection.goal,
7017                                },
7018                            )
7019                        })
7020                    })
7021            })
7022    }
7023
7024    pub fn show_headers(&self) -> bool {
7025        self.show_headers
7026    }
7027
7028    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7029        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7030    }
7031
7032    pub fn all_diff_hunks_expanded(&self) -> bool {
7033        self.all_diff_hunks_expanded
7034    }
7035
7036    /// Visually annotates a position or range with the `Debug` representation of a value. The
7037    /// callsite of this function is used as a key - previous annotations will be removed.
7038    #[cfg(debug_assertions)]
7039    #[track_caller]
7040    pub fn debug<V, R>(&self, ranges: &R, value: V)
7041    where
7042        R: debug::ToMultiBufferDebugRanges,
7043        V: std::fmt::Debug,
7044    {
7045        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7046    }
7047
7048    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7049    /// debug annotations with the same key will be removed. The key is also used to determine the
7050    /// annotation's color.
7051    #[cfg(debug_assertions)]
7052    #[track_caller]
7053    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7054    where
7055        K: std::hash::Hash + 'static,
7056        R: debug::ToMultiBufferDebugRanges,
7057        V: std::fmt::Debug,
7058    {
7059        let text_ranges = ranges
7060            .to_multi_buffer_debug_ranges(self)
7061            .into_iter()
7062            .flat_map(|range| {
7063                self.range_to_buffer_ranges(range.start..=range.end)
7064                    .into_iter()
7065                    .map(|(buffer, range, _excerpt_id)| {
7066                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7067                    })
7068            })
7069            .collect();
7070        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7071            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7072        });
7073    }
7074
7075    fn excerpt_edits_for_diff_change(
7076        &self,
7077        buffer_state: &BufferState,
7078        diff_change_range: Range<usize>,
7079    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7080        let mut excerpt_edits = Vec::new();
7081        for locator in &buffer_state.excerpts {
7082            let mut cursor = self
7083                .excerpts
7084                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7085            cursor.seek_forward(&Some(locator), Bias::Left);
7086            if let Some(excerpt) = cursor.item()
7087                && excerpt.locator == *locator
7088            {
7089                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7090                if diff_change_range.end < excerpt_buffer_range.start
7091                    || diff_change_range.start > excerpt_buffer_range.end
7092                {
7093                    continue;
7094                }
7095                let excerpt_start = cursor.start().1;
7096                let excerpt_len = excerpt.text_summary.len;
7097                let diff_change_start_in_excerpt = diff_change_range
7098                    .start
7099                    .saturating_sub(excerpt_buffer_range.start);
7100                let diff_change_end_in_excerpt = diff_change_range
7101                    .end
7102                    .saturating_sub(excerpt_buffer_range.start);
7103                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7104                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7105                excerpt_edits.push(Edit {
7106                    old: edit_start..edit_end,
7107                    new: edit_start..edit_end,
7108                });
7109            }
7110        }
7111        excerpt_edits
7112    }
7113}
7114
7115#[cfg(any(test, feature = "test-support"))]
7116impl MultiBufferSnapshot {
7117    pub fn random_byte_range(
7118        &self,
7119        start_offset: MultiBufferOffset,
7120        rng: &mut impl rand::Rng,
7121    ) -> Range<MultiBufferOffset> {
7122        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7123        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7124        start..end
7125    }
7126
7127    #[cfg(any(test, feature = "test-support"))]
7128    fn check_invariants(&self) {
7129        let excerpts = self.excerpts.items(());
7130        let excerpt_ids = self.excerpt_ids.items(());
7131
7132        for (ix, excerpt) in excerpts.iter().enumerate() {
7133            if ix == 0 {
7134                if excerpt.locator <= Locator::min() {
7135                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7136                }
7137            } else if excerpt.locator <= excerpts[ix - 1].locator {
7138                panic!("excerpts are out-of-order: {:?}", excerpts);
7139            }
7140        }
7141
7142        for (ix, entry) in excerpt_ids.iter().enumerate() {
7143            if ix == 0 {
7144                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7145                    panic!("invalid first excerpt id {:?}", entry.id);
7146                }
7147            } else if entry.id <= excerpt_ids[ix - 1].id {
7148                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7149            }
7150        }
7151
7152        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7153            panic!(
7154                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7155                self.excerpts.summary().text,
7156                self.diff_transforms.summary().input,
7157                self.diff_transforms.items(()),
7158            );
7159        }
7160
7161        let mut prev_transform: Option<&DiffTransform> = None;
7162        for item in self.diff_transforms.iter() {
7163            if let DiffTransform::BufferContent {
7164                summary,
7165                inserted_hunk_info,
7166            } = item
7167            {
7168                if let Some(DiffTransform::BufferContent {
7169                    inserted_hunk_info: prev_inserted_hunk_info,
7170                    ..
7171                }) = prev_transform
7172                    && *inserted_hunk_info == *prev_inserted_hunk_info
7173                {
7174                    panic!(
7175                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7176                        self.diff_transforms.items(())
7177                    );
7178                }
7179                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7180                    panic!("empty buffer content transform");
7181                }
7182            }
7183            prev_transform = Some(item);
7184        }
7185    }
7186}
7187
7188impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7189where
7190    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7191    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7192{
7193    #[instrument(skip_all)]
7194    fn seek(&mut self, position: &MBD) {
7195        let position = OutputDimension(*position);
7196        self.cached_region.take();
7197        self.diff_transforms.seek(&position, Bias::Right);
7198        if self.diff_transforms.item().is_none()
7199            && self.diff_transforms.start().output_dimension == position
7200        {
7201            self.diff_transforms.prev();
7202        }
7203
7204        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7205        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7206            let overshoot = position - self.diff_transforms.start().output_dimension;
7207            excerpt_position += overshoot;
7208        }
7209
7210        self.excerpts.seek(&excerpt_position, Bias::Right);
7211        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7212            self.excerpts.prev();
7213        }
7214    }
7215
7216    fn seek_forward(&mut self, position: &MBD) {
7217        let position = OutputDimension(*position);
7218        self.cached_region.take();
7219        self.diff_transforms.seek_forward(&position, Bias::Right);
7220        if self.diff_transforms.item().is_none()
7221            && self.diff_transforms.start().output_dimension == position
7222        {
7223            self.diff_transforms.prev();
7224        }
7225
7226        let overshoot = position - self.diff_transforms.start().output_dimension;
7227        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7228        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7229            excerpt_position += overshoot;
7230        }
7231
7232        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7233        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7234            self.excerpts.prev();
7235        }
7236    }
7237
7238    fn next_excerpt(&mut self) {
7239        self.excerpts.next();
7240        self.seek_to_start_of_current_excerpt();
7241    }
7242
7243    fn prev_excerpt(&mut self) {
7244        self.excerpts.prev();
7245        self.seek_to_start_of_current_excerpt();
7246    }
7247
7248    fn seek_to_start_of_current_excerpt(&mut self) {
7249        self.cached_region.take();
7250
7251        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7252            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7253            && self.diff_transforms.next_item().is_some()
7254        {
7255            self.diff_transforms.next();
7256        }
7257    }
7258
7259    fn next_excerpt_forwards(&mut self) {
7260        self.excerpts.next();
7261        self.seek_to_start_of_current_excerpt_forward();
7262    }
7263
7264    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7265        self.cached_region.take();
7266
7267        if self
7268            .diff_transforms
7269            .seek_forward(self.excerpts.start(), Bias::Left)
7270            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7271            && self.diff_transforms.next_item().is_some()
7272        {
7273            self.diff_transforms.next();
7274        }
7275    }
7276
7277    fn next(&mut self) {
7278        self.cached_region.take();
7279        match self
7280            .diff_transforms
7281            .end()
7282            .excerpt_dimension
7283            .cmp(&self.excerpts.end())
7284        {
7285            cmp::Ordering::Less => self.diff_transforms.next(),
7286            cmp::Ordering::Greater => self.excerpts.next(),
7287            cmp::Ordering::Equal => {
7288                self.diff_transforms.next();
7289                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7290                    || self.diff_transforms.item().is_none()
7291                {
7292                    self.excerpts.next();
7293                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7294                    self.diff_transforms.item()
7295                    && self
7296                        .excerpts
7297                        .item()
7298                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7299                {
7300                    self.excerpts.next();
7301                }
7302            }
7303        }
7304    }
7305
7306    fn prev(&mut self) {
7307        self.cached_region.take();
7308        match self
7309            .diff_transforms
7310            .start()
7311            .excerpt_dimension
7312            .cmp(self.excerpts.start())
7313        {
7314            cmp::Ordering::Less => self.excerpts.prev(),
7315            cmp::Ordering::Greater => self.diff_transforms.prev(),
7316            cmp::Ordering::Equal => {
7317                self.diff_transforms.prev();
7318                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7319                    || self.diff_transforms.item().is_none()
7320                {
7321                    self.excerpts.prev();
7322                }
7323            }
7324        }
7325    }
7326
7327    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7328        self.cached_region
7329            .get_or_init(|| self.build_region())
7330            .as_ref()
7331    }
7332
7333    fn is_at_start_of_excerpt(&mut self) -> bool {
7334        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7335            return false;
7336        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7337            return true;
7338        }
7339
7340        self.diff_transforms.prev();
7341        let prev_transform = self.diff_transforms.item();
7342        self.diff_transforms.next();
7343
7344        prev_transform.is_none_or(|next_transform| {
7345            matches!(next_transform, DiffTransform::BufferContent { .. })
7346        })
7347    }
7348
7349    fn is_at_end_of_excerpt(&self) -> bool {
7350        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7351            return false;
7352        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7353            || self.diff_transforms.item().is_none()
7354        {
7355            return true;
7356        }
7357
7358        let next_transform = self.diff_transforms.next_item();
7359        next_transform.is_none_or(|next_transform| match next_transform {
7360            DiffTransform::BufferContent { .. } => true,
7361            DiffTransform::DeletedHunk { hunk_info, .. } => self
7362                .excerpts
7363                .item()
7364                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7365        })
7366    }
7367
7368    fn main_buffer_position(&self) -> Option<BD> {
7369        let excerpt = self.excerpts.item()?;
7370        let buffer = &excerpt.buffer;
7371        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7372        let mut buffer_start = buffer_context_start;
7373        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7374        buffer_start += overshoot;
7375        Some(buffer_start)
7376    }
7377
7378    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7379        let excerpt = self.excerpts.item()?;
7380        match self.diff_transforms.item()? {
7381            DiffTransform::DeletedHunk {
7382                buffer_id,
7383                base_text_byte_range,
7384                has_trailing_newline,
7385                hunk_info,
7386                ..
7387            } => {
7388                let diff = self.diffs.get(buffer_id)?;
7389                let buffer = diff.base_text();
7390                let mut rope_cursor = buffer.as_rope().cursor(0);
7391                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7392                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7393                let mut buffer_end = buffer_start;
7394                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7395                let start = self.diff_transforms.start().output_dimension.0;
7396                let end = self.diff_transforms.end().output_dimension.0;
7397                Some(MultiBufferRegion {
7398                    buffer,
7399                    excerpt,
7400                    has_trailing_newline: *has_trailing_newline,
7401                    is_main_buffer: false,
7402                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7403                        hunk_info.hunk_secondary_status,
7404                    )),
7405                    buffer_range: buffer_start..buffer_end,
7406                    range: start..end,
7407                })
7408            }
7409            DiffTransform::BufferContent {
7410                inserted_hunk_info, ..
7411            } => {
7412                let buffer = &excerpt.buffer;
7413                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7414
7415                let mut start = self.diff_transforms.start().output_dimension.0;
7416                let mut buffer_start = buffer_context_start;
7417                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7418                    let overshoot =
7419                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7420                    start += overshoot;
7421                } else {
7422                    let overshoot =
7423                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7424                    buffer_start += overshoot;
7425                }
7426
7427                let mut end;
7428                let mut buffer_end;
7429                let has_trailing_newline;
7430                let transform_end = self.diff_transforms.end();
7431                if transform_end.excerpt_dimension < self.excerpts.end() {
7432                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7433                    end = transform_end.output_dimension.0;
7434                    buffer_end = buffer_context_start;
7435                    buffer_end += overshoot;
7436                    has_trailing_newline = false;
7437                } else {
7438                    let overshoot =
7439                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7440                    end = self.diff_transforms.start().output_dimension.0;
7441                    end += overshoot;
7442                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7443                    has_trailing_newline = excerpt.has_trailing_newline;
7444                };
7445
7446                let diff_hunk_status = inserted_hunk_info.map(|info| {
7447                    if info.is_logically_deleted {
7448                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7449                    } else {
7450                        DiffHunkStatus::added(info.hunk_secondary_status)
7451                    }
7452                });
7453
7454                Some(MultiBufferRegion {
7455                    buffer,
7456                    excerpt,
7457                    has_trailing_newline,
7458                    is_main_buffer: true,
7459                    diff_hunk_status,
7460                    buffer_range: buffer_start..buffer_end,
7461                    range: start..end,
7462                })
7463            }
7464        }
7465    }
7466
7467    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7468        let excerpt = self.excerpts.item()?;
7469        match self.diff_transforms.item()? {
7470            &DiffTransform::DeletedHunk { .. } => {
7471                let start = self.diff_transforms.start().output_dimension.0;
7472                let end = self.diff_transforms.end().output_dimension.0;
7473                Some((excerpt, start..end))
7474            }
7475            DiffTransform::BufferContent { .. } => {
7476                let mut start = self.diff_transforms.start().output_dimension.0;
7477                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7478                    let overshoot =
7479                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7480                    start += overshoot;
7481                }
7482
7483                let mut end;
7484                let transform_end = self.diff_transforms.end();
7485                if transform_end.excerpt_dimension < self.excerpts.end() {
7486                    end = transform_end.output_dimension.0;
7487                } else {
7488                    let overshoot =
7489                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7490                    end = self.diff_transforms.start().output_dimension.0;
7491                    end += overshoot;
7492                };
7493
7494                Some((excerpt, start..end))
7495            }
7496        }
7497    }
7498
7499    fn excerpt(&self) -> Option<&'a Excerpt> {
7500        self.excerpts.item()
7501    }
7502}
7503
7504impl Excerpt {
7505    fn new(
7506        id: ExcerptId,
7507        locator: Locator,
7508        buffer_id: BufferId,
7509        buffer: Arc<BufferSnapshot>,
7510        range: ExcerptRange<text::Anchor>,
7511        has_trailing_newline: bool,
7512    ) -> Self {
7513        Excerpt {
7514            id,
7515            locator,
7516            max_buffer_row: range.context.end.to_point(&buffer).row,
7517            text_summary: buffer
7518                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7519            buffer_id,
7520            buffer,
7521            range,
7522            has_trailing_newline,
7523        }
7524    }
7525
7526    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7527        let content_start = self.range.context.start.to_offset(&self.buffer);
7528        let chunks_start = content_start + range.start;
7529        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7530
7531        let has_footer = self.has_trailing_newline
7532            && range.start <= self.text_summary.len
7533            && range.end > self.text_summary.len;
7534
7535        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7536
7537        ExcerptChunks {
7538            excerpt_id: self.id,
7539            content_chunks,
7540            has_footer,
7541        }
7542    }
7543
7544    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7545        let content_start = self.range.context.start.to_offset(&self.buffer);
7546        let chunks_start = content_start + range.start;
7547        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7548        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7549        excerpt_chunks.has_footer = self.has_trailing_newline
7550            && range.start <= self.text_summary.len
7551            && range.end > self.text_summary.len;
7552    }
7553
7554    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7555        if text_anchor
7556            .cmp(&self.range.context.start, &self.buffer)
7557            .is_lt()
7558        {
7559            self.range.context.start
7560        } else if text_anchor
7561            .cmp(&self.range.context.end, &self.buffer)
7562            .is_gt()
7563        {
7564            self.range.context.end
7565        } else {
7566            text_anchor
7567        }
7568    }
7569
7570    fn contains(&self, anchor: &Anchor) -> bool {
7571        (anchor.text_anchor.buffer_id == None
7572            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7573            && self
7574                .range
7575                .context
7576                .start
7577                .cmp(&anchor.text_anchor, &self.buffer)
7578                .is_le()
7579            && self
7580                .range
7581                .context
7582                .end
7583                .cmp(&anchor.text_anchor, &self.buffer)
7584                .is_ge()
7585    }
7586
7587    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7588    fn buffer_start_offset(&self) -> BufferOffset {
7589        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7590    }
7591
7592    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7593    fn buffer_end_offset(&self) -> BufferOffset {
7594        self.buffer_start_offset() + self.text_summary.len
7595    }
7596}
7597
7598impl<'a> MultiBufferExcerpt<'a> {
7599    pub fn id(&self) -> ExcerptId {
7600        self.excerpt.id
7601    }
7602
7603    pub fn buffer_id(&self) -> BufferId {
7604        self.excerpt.buffer_id
7605    }
7606
7607    pub fn start_anchor(&self) -> Anchor {
7608        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7609    }
7610
7611    pub fn end_anchor(&self) -> Anchor {
7612        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7613    }
7614
7615    pub fn buffer(&self) -> &'a BufferSnapshot {
7616        &self.excerpt.buffer
7617    }
7618
7619    pub fn buffer_range(&self) -> Range<BufferOffset> {
7620        self.buffer_offset
7621            ..BufferOffset(
7622                self.excerpt
7623                    .range
7624                    .context
7625                    .end
7626                    .to_offset(&self.excerpt.buffer.text),
7627            )
7628    }
7629
7630    pub fn start_offset(&self) -> MultiBufferOffset {
7631        self.offset
7632    }
7633
7634    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7635    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7636        self.map_range_to_buffer(offset..offset).start
7637    }
7638
7639    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7640    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7641        self.diff_transforms
7642            .seek(&OutputDimension(range.start), Bias::Right);
7643        let start = self.map_offset_to_buffer_internal(range.start);
7644        let end = if range.end > range.start {
7645            self.diff_transforms
7646                .seek_forward(&OutputDimension(range.end), Bias::Right);
7647            self.map_offset_to_buffer_internal(range.end)
7648        } else {
7649            start
7650        };
7651        start..end
7652    }
7653
7654    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7655        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7656        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7657            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7658        };
7659        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7660        self.buffer_offset + offset_in_excerpt
7661    }
7662
7663    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7664    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7665        self.map_range_from_buffer(buffer_offset..buffer_offset)
7666            .start
7667    }
7668
7669    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7670    pub fn map_range_from_buffer(
7671        &mut self,
7672        buffer_range: Range<BufferOffset>,
7673    ) -> Range<MultiBufferOffset> {
7674        if buffer_range.start < self.buffer_offset {
7675            log::warn!(
7676                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7677            );
7678            return self.offset..self.offset;
7679        }
7680        let overshoot = buffer_range.start - self.buffer_offset;
7681        let excerpt_offset = self.excerpt_offset + overshoot;
7682        let excerpt_seek_dim = excerpt_offset;
7683        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7684        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7685            log::warn!(
7686                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7687            );
7688            return self.offset..self.offset;
7689        }
7690        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7691        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7692
7693        let end = if buffer_range.start < buffer_range.end {
7694            let overshoot = buffer_range.end - self.buffer_offset;
7695            let excerpt_offset = self.excerpt_offset + overshoot;
7696            let excerpt_seek_dim = excerpt_offset;
7697            self.diff_transforms
7698                .seek_forward(&excerpt_seek_dim, Bias::Right);
7699            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7700            // todo(lw): Clamp end to the excerpt boundaries
7701            self.diff_transforms.start().output_dimension.0 + overshoot
7702        } else {
7703            start
7704        };
7705
7706        start..end
7707    }
7708
7709    /// Returns true if the entirety of the given range is in the buffer's excerpt
7710    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7711        range.start >= self.excerpt.buffer_start_offset()
7712            && range.end <= self.excerpt.buffer_end_offset()
7713    }
7714
7715    /// Returns true if any part of the given range is in the buffer's excerpt
7716    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7717        range.start <= self.excerpt.buffer_end_offset()
7718            && range.end >= self.excerpt.buffer_start_offset()
7719    }
7720
7721    pub fn max_buffer_row(&self) -> u32 {
7722        self.excerpt.max_buffer_row
7723    }
7724}
7725
7726impl ExcerptId {
7727    pub fn min() -> Self {
7728        Self(0)
7729    }
7730
7731    pub fn max() -> Self {
7732        Self(u32::MAX)
7733    }
7734
7735    pub fn to_proto(self) -> u64 {
7736        self.0 as _
7737    }
7738
7739    pub fn from_proto(proto: u64) -> Self {
7740        Self(proto as _)
7741    }
7742
7743    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7744        let a = snapshot.excerpt_locator_for_id(*self);
7745        let b = snapshot.excerpt_locator_for_id(*other);
7746        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7747    }
7748}
7749
7750impl From<ExcerptId> for usize {
7751    fn from(val: ExcerptId) -> Self {
7752        val.0 as usize
7753    }
7754}
7755
7756impl fmt::Debug for Excerpt {
7757    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7758        f.debug_struct("Excerpt")
7759            .field("id", &self.id)
7760            .field("locator", &self.locator)
7761            .field("buffer_id", &self.buffer_id)
7762            .field("range", &self.range)
7763            .field("text_summary", &self.text_summary)
7764            .field("has_trailing_newline", &self.has_trailing_newline)
7765            .finish()
7766    }
7767}
7768
7769impl sum_tree::Item for Excerpt {
7770    type Summary = ExcerptSummary;
7771
7772    fn summary(&self, _cx: ()) -> Self::Summary {
7773        let mut text = self.text_summary;
7774        if self.has_trailing_newline {
7775            text += TextSummary::from("\n");
7776        }
7777        ExcerptSummary {
7778            excerpt_id: self.id,
7779            excerpt_locator: self.locator.clone(),
7780            widest_line_number: self.max_buffer_row,
7781            text: text.into(),
7782            count: 1,
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        self.count += summary.count;
7878    }
7879}
7880
7881impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7882    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7883        Ord::cmp(&Some(self), cursor_location)
7884    }
7885}
7886
7887impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7888    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7889        Ord::cmp(self, &cursor_location.excerpt_locator)
7890    }
7891}
7892
7893impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7894where
7895    MBD: MultiBufferDimension + Default,
7896{
7897    fn zero(_: ()) -> Self {
7898        ExcerptDimension(MBD::default())
7899    }
7900
7901    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7902        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7903    }
7904}
7905
7906impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7907    fn zero(_cx: ()) -> Self {
7908        Default::default()
7909    }
7910
7911    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7912        *self = Some(&summary.excerpt_locator);
7913    }
7914}
7915
7916impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7917    fn zero(_cx: ()) -> Self {
7918        Default::default()
7919    }
7920
7921    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7922        *self = Some(summary.excerpt_id);
7923    }
7924}
7925
7926#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7927struct OutputDimension<T>(T);
7928
7929impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7930    fn eq(&self, other: &T) -> bool {
7931        self.0 == *other
7932    }
7933}
7934
7935impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7936    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7937        self.0.partial_cmp(other)
7938    }
7939}
7940
7941impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7942where
7943    T: ops::Sub<U, Output = R>,
7944{
7945    type Output = R;
7946
7947    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7948        self.0 - other.0
7949    }
7950}
7951
7952impl<R, T, U> ops::Add<U> for OutputDimension<T>
7953where
7954    T: ops::Add<U, Output = R>,
7955{
7956    type Output = OutputDimension<R>;
7957
7958    fn add(self, other: U) -> Self::Output {
7959        OutputDimension(self.0 + other)
7960    }
7961}
7962
7963impl<T, U> AddAssign<U> for OutputDimension<T>
7964where
7965    T: AddAssign<U>,
7966{
7967    fn add_assign(&mut self, other: U) {
7968        self.0 += other;
7969    }
7970}
7971
7972impl<T, U> SubAssign<U> for OutputDimension<T>
7973where
7974    T: SubAssign<U>,
7975{
7976    fn sub_assign(&mut self, other: U) {
7977        self.0 -= other;
7978    }
7979}
7980
7981#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7982struct ExcerptDimension<T>(T);
7983
7984impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7985    fn eq(&self, other: &T) -> bool {
7986        self.0 == *other
7987    }
7988}
7989
7990impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7991    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7992        self.0.partial_cmp(other)
7993    }
7994}
7995
7996impl ExcerptOffset {
7997    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7998        self.0.saturating_sub(other.0)
7999    }
8000}
8001
8002impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8003where
8004    T: ops::Sub<U, Output = R>,
8005{
8006    type Output = R;
8007
8008    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8009        self.0 - other.0
8010    }
8011}
8012
8013impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8014where
8015    T: ops::Add<U, Output = R>,
8016{
8017    type Output = ExcerptDimension<R>;
8018
8019    fn add(self, other: U) -> Self::Output {
8020        ExcerptDimension(self.0 + other)
8021    }
8022}
8023
8024impl<T, U> AddAssign<U> for ExcerptDimension<T>
8025where
8026    T: AddAssign<U>,
8027{
8028    fn add_assign(&mut self, other: U) {
8029        self.0 += other;
8030    }
8031}
8032
8033impl<T, U> SubAssign<U> for ExcerptDimension<T>
8034where
8035    T: SubAssign<U>,
8036{
8037    fn sub_assign(&mut self, other: U) {
8038        self.0 -= other;
8039    }
8040}
8041
8042impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8043    fn zero(_: ()) -> Self {
8044        MultiBufferOffset::ZERO
8045    }
8046
8047    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8048        *self += summary.output.len;
8049    }
8050}
8051
8052impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8053    for ExcerptDimension<MBD>
8054where
8055    MBD: MultiBufferDimension + Ord,
8056{
8057    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8058        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8059    }
8060}
8061
8062impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8063    for ExcerptDimension<MBD>
8064where
8065    MBD: MultiBufferDimension + Ord,
8066{
8067    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8068        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8069    }
8070}
8071
8072impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8073    for ExcerptDimension<MBD>
8074{
8075    fn zero(_: ()) -> Self {
8076        ExcerptDimension(MBD::default())
8077    }
8078
8079    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8080        self.0.add_mb_text_summary(&summary.input)
8081    }
8082}
8083
8084impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8085    for OutputDimension<MBD>
8086where
8087    MBD: MultiBufferDimension + Ord,
8088{
8089    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8090        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8091    }
8092}
8093
8094impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8095    for OutputDimension<MBD>
8096{
8097    fn zero(_: ()) -> Self {
8098        OutputDimension(MBD::default())
8099    }
8100
8101    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8102        self.0.add_mb_text_summary(&summary.output)
8103    }
8104}
8105
8106impl MultiBufferRows<'_> {
8107    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8108        self.point = Point::new(row, 0);
8109        self.cursor.seek(&self.point);
8110    }
8111}
8112
8113impl Iterator for MultiBufferRows<'_> {
8114    type Item = RowInfo;
8115
8116    fn next(&mut self) -> Option<Self::Item> {
8117        if self.is_empty && self.point.row == 0 {
8118            self.point += Point::new(1, 0);
8119            return Some(RowInfo {
8120                buffer_id: None,
8121                buffer_row: Some(0),
8122                multibuffer_row: Some(MultiBufferRow(0)),
8123                diff_status: None,
8124                expand_info: None,
8125                wrapped_buffer_row: None,
8126            });
8127        }
8128
8129        let mut region = self.cursor.region()?.clone();
8130        while self.point >= region.range.end {
8131            self.cursor.next();
8132            if let Some(next_region) = self.cursor.region() {
8133                region = next_region.clone();
8134            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8135                let multibuffer_row = MultiBufferRow(self.point.row);
8136                let last_excerpt = self
8137                    .cursor
8138                    .excerpts
8139                    .item()
8140                    .or(self.cursor.excerpts.prev_item())?;
8141                let last_row = last_excerpt
8142                    .range
8143                    .context
8144                    .end
8145                    .to_point(&last_excerpt.buffer)
8146                    .row;
8147
8148                let first_row = last_excerpt
8149                    .range
8150                    .context
8151                    .start
8152                    .to_point(&last_excerpt.buffer)
8153                    .row;
8154
8155                let expand_info = if self.is_singleton {
8156                    None
8157                } else {
8158                    let needs_expand_up = first_row == last_row
8159                        && last_row > 0
8160                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8161                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8162
8163                    if needs_expand_up && needs_expand_down {
8164                        Some(ExpandExcerptDirection::UpAndDown)
8165                    } else if needs_expand_up {
8166                        Some(ExpandExcerptDirection::Up)
8167                    } else if needs_expand_down {
8168                        Some(ExpandExcerptDirection::Down)
8169                    } else {
8170                        None
8171                    }
8172                    .map(|direction| ExpandInfo {
8173                        direction,
8174                        excerpt_id: last_excerpt.id,
8175                    })
8176                };
8177                self.point += Point::new(1, 0);
8178                return Some(RowInfo {
8179                    buffer_id: Some(last_excerpt.buffer_id),
8180                    buffer_row: Some(last_row),
8181                    multibuffer_row: Some(multibuffer_row),
8182                    diff_status: None,
8183                    wrapped_buffer_row: None,
8184                    expand_info,
8185                });
8186            } else {
8187                return None;
8188            };
8189        }
8190
8191        let overshoot = self.point - region.range.start;
8192        let buffer_point = region.buffer_range.start + overshoot;
8193        let expand_info = if self.is_singleton {
8194            None
8195        } else {
8196            let needs_expand_up = self.point.row == region.range.start.row
8197                && self.cursor.is_at_start_of_excerpt()
8198                && buffer_point.row > 0;
8199            let needs_expand_down = (region.excerpt.has_trailing_newline
8200                && self.point.row + 1 == region.range.end.row
8201                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8202                && self.cursor.is_at_end_of_excerpt()
8203                && buffer_point.row < region.buffer.max_point().row;
8204
8205            if needs_expand_up && needs_expand_down {
8206                Some(ExpandExcerptDirection::UpAndDown)
8207            } else if needs_expand_up {
8208                Some(ExpandExcerptDirection::Up)
8209            } else if needs_expand_down {
8210                Some(ExpandExcerptDirection::Down)
8211            } else {
8212                None
8213            }
8214            .map(|direction| ExpandInfo {
8215                direction,
8216                excerpt_id: region.excerpt.id,
8217            })
8218        };
8219
8220        let result = Some(RowInfo {
8221            buffer_id: Some(region.buffer.remote_id()),
8222            buffer_row: Some(buffer_point.row),
8223            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8224            diff_status: region
8225                .diff_hunk_status
8226                .filter(|_| self.point < region.range.end),
8227            expand_info,
8228            wrapped_buffer_row: None,
8229        });
8230        self.point += Point::new(1, 0);
8231        result
8232    }
8233}
8234
8235impl<'a> MultiBufferChunks<'a> {
8236    pub fn offset(&self) -> MultiBufferOffset {
8237        self.range.start
8238    }
8239
8240    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8241        self.diff_transforms.seek(&range.end, Bias::Right);
8242        let mut excerpt_end = self.diff_transforms.start().1;
8243        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8244            let overshoot = range.end - self.diff_transforms.start().0;
8245            excerpt_end += overshoot;
8246        }
8247
8248        self.diff_transforms.seek(&range.start, Bias::Right);
8249        let mut excerpt_start = self.diff_transforms.start().1;
8250        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8251            let overshoot = range.start - self.diff_transforms.start().0;
8252            excerpt_start += overshoot;
8253        }
8254
8255        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8256        self.buffer_chunk.take();
8257        self.range = range;
8258    }
8259
8260    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8261        self.excerpt_offset_range = new_range.clone();
8262        self.excerpts.seek(&new_range.start, Bias::Right);
8263        if let Some(excerpt) = self.excerpts.item() {
8264            let excerpt_start = *self.excerpts.start();
8265            if let Some(excerpt_chunks) = self
8266                .excerpt_chunks
8267                .as_mut()
8268                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8269            {
8270                excerpt.seek_chunks(
8271                    excerpt_chunks,
8272                    (self.excerpt_offset_range.start - excerpt_start)
8273                        ..(self.excerpt_offset_range.end - excerpt_start),
8274                );
8275            } else {
8276                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8277                    (self.excerpt_offset_range.start - excerpt_start)
8278                        ..(self.excerpt_offset_range.end - excerpt_start),
8279                    self.language_aware,
8280                ));
8281            }
8282        } else {
8283            self.excerpt_chunks = None;
8284        }
8285    }
8286
8287    #[ztracing::instrument(skip_all)]
8288    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8289        loop {
8290            if self.excerpt_offset_range.is_empty() {
8291                return None;
8292            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8293                self.excerpt_offset_range.start += chunk.text.len();
8294                return Some(chunk);
8295            } else {
8296                self.excerpts.next();
8297                let excerpt = self.excerpts.item()?;
8298                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8299                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8300                    self.language_aware,
8301                ));
8302            }
8303        }
8304    }
8305}
8306
8307impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8308    type Item = &'a str;
8309
8310    fn next(&mut self) -> Option<Self::Item> {
8311        let mut region = self.cursor.region()?;
8312        if self.offset == region.range.start {
8313            self.cursor.prev();
8314            region = self.cursor.region()?;
8315            let start_overshoot = self.start.saturating_sub(region.range.start);
8316            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8317                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8318            ));
8319        }
8320
8321        if self.offset == region.range.end && region.has_trailing_newline {
8322            self.offset -= 1;
8323            Some("\n")
8324        } else {
8325            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8326            self.offset -= chunk.len();
8327            Some(chunk)
8328        }
8329    }
8330}
8331
8332impl<'a> Iterator for MultiBufferChunks<'a> {
8333    type Item = Chunk<'a>;
8334
8335    #[ztracing::instrument(skip_all)]
8336    fn next(&mut self) -> Option<Chunk<'a>> {
8337        if self.range.start >= self.range.end {
8338            return None;
8339        }
8340        if self.range.start == self.diff_transforms.end().0 {
8341            self.diff_transforms.next();
8342        }
8343
8344        let diff_transform_start = self.diff_transforms.start().0;
8345        let diff_transform_end = self.diff_transforms.end().0;
8346        debug_assert!(
8347            self.range.start < diff_transform_end,
8348            "{:?} < {:?} of ({1:?}..{2:?})",
8349            self.range.start,
8350            diff_transform_end,
8351            diff_transform_start
8352        );
8353
8354        let diff_transform = self.diff_transforms.item()?;
8355        match diff_transform {
8356            DiffTransform::BufferContent { .. } => {
8357                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8358                    chunk
8359                } else {
8360                    let chunk = self.next_excerpt_chunk().unwrap();
8361                    self.buffer_chunk.insert(chunk)
8362                };
8363
8364                let chunk_end = self.range.start + chunk.text.len();
8365                let diff_transform_end = diff_transform_end.min(self.range.end);
8366
8367                if diff_transform_end < chunk_end {
8368                    let split_idx = diff_transform_end - self.range.start;
8369                    let (before, after) = chunk.text.split_at(split_idx);
8370                    self.range.start = diff_transform_end;
8371                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8372                    let chars = chunk.chars & mask;
8373                    let tabs = chunk.tabs & mask;
8374                    let newlines = chunk.newlines & mask;
8375
8376                    chunk.text = after;
8377                    chunk.chars = chunk.chars >> split_idx;
8378                    chunk.tabs = chunk.tabs >> split_idx;
8379                    chunk.newlines = chunk.newlines >> split_idx;
8380
8381                    Some(Chunk {
8382                        text: before,
8383                        chars,
8384                        tabs,
8385                        newlines,
8386                        ..chunk.clone()
8387                    })
8388                } else {
8389                    self.range.start = chunk_end;
8390                    self.buffer_chunk.take()
8391                }
8392            }
8393            DiffTransform::DeletedHunk {
8394                buffer_id,
8395                base_text_byte_range,
8396                has_trailing_newline,
8397                ..
8398            } => {
8399                let base_text_start =
8400                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8401                let base_text_end =
8402                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8403                let base_text_end = base_text_end.min(base_text_byte_range.end);
8404
8405                let mut chunks = if let Some((_, mut chunks)) = self
8406                    .diff_base_chunks
8407                    .take()
8408                    .filter(|(id, _)| id == buffer_id)
8409                {
8410                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8411                    {
8412                        chunks.seek(base_text_start..base_text_end);
8413                    }
8414                    chunks
8415                } else {
8416                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8417                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8418                };
8419
8420                let chunk = if let Some(chunk) = chunks.next() {
8421                    self.range.start += chunk.text.len();
8422                    self.diff_base_chunks = Some((*buffer_id, chunks));
8423                    chunk
8424                } else {
8425                    debug_assert!(has_trailing_newline);
8426                    self.range.start += "\n".len();
8427                    Chunk {
8428                        text: "\n",
8429                        chars: 1u128,
8430                        newlines: 1u128,
8431                        ..Default::default()
8432                    }
8433                };
8434                Some(chunk)
8435            }
8436        }
8437    }
8438}
8439
8440impl MultiBufferBytes<'_> {
8441    fn consume(&mut self, len: usize) {
8442        self.range.start += len;
8443        self.chunk = &self.chunk[len..];
8444
8445        if !self.range.is_empty() && self.chunk.is_empty() {
8446            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8447                self.chunk = chunk;
8448            } else if self.has_trailing_newline {
8449                self.has_trailing_newline = false;
8450                self.chunk = b"\n";
8451            } else {
8452                self.cursor.next();
8453                if let Some(region) = self.cursor.region() {
8454                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8455                        region.buffer_range.start
8456                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8457                                .min(region.buffer_range.end),
8458                    );
8459                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8460                    self.excerpt_bytes = Some(excerpt_bytes);
8461                    self.has_trailing_newline =
8462                        region.has_trailing_newline && self.range.end >= region.range.end;
8463                    if self.chunk.is_empty() && self.has_trailing_newline {
8464                        self.has_trailing_newline = false;
8465                        self.chunk = b"\n";
8466                    }
8467                }
8468            }
8469        }
8470    }
8471}
8472
8473impl<'a> Iterator for MultiBufferBytes<'a> {
8474    type Item = &'a [u8];
8475
8476    fn next(&mut self) -> Option<Self::Item> {
8477        let chunk = self.chunk;
8478        if chunk.is_empty() {
8479            None
8480        } else {
8481            self.consume(chunk.len());
8482            Some(chunk)
8483        }
8484    }
8485}
8486
8487impl io::Read for MultiBufferBytes<'_> {
8488    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8489        let len = cmp::min(buf.len(), self.chunk.len());
8490        buf[..len].copy_from_slice(&self.chunk[..len]);
8491        if len > 0 {
8492            self.consume(len);
8493        }
8494        Ok(len)
8495    }
8496}
8497
8498impl io::Read for ReversedMultiBufferBytes<'_> {
8499    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8500        let len = cmp::min(buf.len(), self.chunk.len());
8501        buf[..len].copy_from_slice(&self.chunk[..len]);
8502        buf[..len].reverse();
8503        if len > 0 {
8504            self.range.end -= len;
8505            self.chunk = &self.chunk[..self.chunk.len() - len];
8506            if !self.range.is_empty()
8507                && self.chunk.is_empty()
8508                && let Some(chunk) = self.chunks.next()
8509            {
8510                self.chunk = chunk.as_bytes();
8511            }
8512        }
8513        Ok(len)
8514    }
8515}
8516
8517impl<'a> Iterator for ExcerptChunks<'a> {
8518    type Item = Chunk<'a>;
8519
8520    fn next(&mut self) -> Option<Self::Item> {
8521        if let Some(chunk) = self.content_chunks.next() {
8522            return Some(chunk);
8523        }
8524
8525        if self.has_footer {
8526            let text = "\n";
8527            let chars = 0b1;
8528            let newlines = 0b1;
8529            self.has_footer = false;
8530            return Some(Chunk {
8531                text,
8532                chars,
8533                newlines,
8534                ..Default::default()
8535            });
8536        }
8537
8538        None
8539    }
8540}
8541
8542impl ToOffset for Point {
8543    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8544        snapshot.point_to_offset(*self)
8545    }
8546    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8547        snapshot.point_to_offset_utf16(*self)
8548    }
8549}
8550
8551impl ToOffset for MultiBufferOffset {
8552    #[track_caller]
8553    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8554        assert!(
8555            *self <= snapshot.len(),
8556            "offset {} is greater than the snapshot.len() {}",
8557            self.0,
8558            snapshot.len().0,
8559        );
8560        *self
8561    }
8562    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8563        snapshot.offset_to_offset_utf16(*self)
8564    }
8565}
8566
8567impl ToOffset for MultiBufferOffsetUtf16 {
8568    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8569        snapshot.offset_utf16_to_offset(*self)
8570    }
8571
8572    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8573        *self
8574    }
8575}
8576
8577impl ToOffset for PointUtf16 {
8578    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8579        snapshot.point_utf16_to_offset(*self)
8580    }
8581    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8582        snapshot.point_utf16_to_offset_utf16(*self)
8583    }
8584}
8585
8586impl ToPoint for MultiBufferOffset {
8587    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8588        snapshot.offset_to_point(*self)
8589    }
8590    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8591        snapshot.offset_to_point_utf16(*self)
8592    }
8593}
8594
8595impl ToPoint for Point {
8596    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8597        *self
8598    }
8599    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8600        snapshot.point_to_point_utf16(*self)
8601    }
8602}
8603
8604impl ToPoint for PointUtf16 {
8605    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8606        snapshot.point_utf16_to_point(*self)
8607    }
8608    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8609        *self
8610    }
8611}
8612
8613impl From<ExcerptId> for EntityId {
8614    fn from(id: ExcerptId) -> Self {
8615        EntityId::from(id.0 as u64)
8616    }
8617}
8618
8619#[cfg(debug_assertions)]
8620pub mod debug {
8621    use super::*;
8622
8623    pub trait ToMultiBufferDebugRanges {
8624        fn to_multi_buffer_debug_ranges(
8625            &self,
8626            snapshot: &MultiBufferSnapshot,
8627        ) -> Vec<Range<MultiBufferOffset>>;
8628    }
8629
8630    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8631        fn to_multi_buffer_debug_ranges(
8632            &self,
8633            snapshot: &MultiBufferSnapshot,
8634        ) -> Vec<Range<MultiBufferOffset>> {
8635            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8636        }
8637    }
8638
8639    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8640        fn to_multi_buffer_debug_ranges(
8641            &self,
8642            snapshot: &MultiBufferSnapshot,
8643        ) -> Vec<Range<MultiBufferOffset>> {
8644            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8645                .to_multi_buffer_debug_ranges(snapshot)
8646        }
8647    }
8648
8649    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8650        fn to_multi_buffer_debug_ranges(
8651            &self,
8652            snapshot: &MultiBufferSnapshot,
8653        ) -> Vec<Range<MultiBufferOffset>> {
8654            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8655        }
8656    }
8657
8658    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8659        fn to_multi_buffer_debug_ranges(
8660            &self,
8661            snapshot: &MultiBufferSnapshot,
8662        ) -> Vec<Range<MultiBufferOffset>> {
8663            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8664        }
8665    }
8666
8667    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8668        fn to_multi_buffer_debug_ranges(
8669            &self,
8670            snapshot: &MultiBufferSnapshot,
8671        ) -> Vec<Range<MultiBufferOffset>> {
8672            self.iter()
8673                .map(|item| {
8674                    let offset = item.to_offset(snapshot);
8675                    offset..offset
8676                })
8677                .collect()
8678        }
8679    }
8680
8681    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8682        fn to_multi_buffer_debug_ranges(
8683            &self,
8684            snapshot: &MultiBufferSnapshot,
8685        ) -> Vec<Range<MultiBufferOffset>> {
8686            self.iter()
8687                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8688                .collect()
8689        }
8690    }
8691}