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}
 803
 804#[derive(Debug, Clone)]
 805pub struct DiffTransformSummary {
 806    input: MBTextSummary,
 807    output: MBTextSummary,
 808}
 809
 810/// Summary of a string of text.
 811#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 812pub struct MBTextSummary {
 813    /// Length in bytes.
 814    pub len: MultiBufferOffset,
 815    /// Length in UTF-8.
 816    pub chars: usize,
 817    /// Length in UTF-16 code units
 818    pub len_utf16: OffsetUtf16,
 819    /// A point representing the number of lines and the length of the last line.
 820    ///
 821    /// In other words, it marks the point after the last byte in the text, (if
 822    /// EOF was a character, this would be its position).
 823    pub lines: Point,
 824    /// How many `char`s are in the first line
 825    pub first_line_chars: u32,
 826    /// How many `char`s are in the last line
 827    pub last_line_chars: u32,
 828    /// How many UTF-16 code units are in the last line
 829    pub last_line_len_utf16: u32,
 830    /// The row idx of the longest row
 831    pub longest_row: u32,
 832    /// How many `char`s are in the longest row
 833    pub longest_row_chars: u32,
 834}
 835
 836impl From<TextSummary> for MBTextSummary {
 837    fn from(summary: TextSummary) -> Self {
 838        MBTextSummary {
 839            len: MultiBufferOffset(summary.len),
 840            chars: summary.chars,
 841            len_utf16: summary.len_utf16,
 842            lines: summary.lines,
 843            first_line_chars: summary.first_line_chars,
 844            last_line_chars: summary.last_line_chars,
 845            last_line_len_utf16: summary.last_line_len_utf16,
 846            longest_row: summary.longest_row,
 847            longest_row_chars: summary.longest_row_chars,
 848        }
 849    }
 850}
 851
 852impl From<MBTextSummary> for TextSummary {
 853    fn from(summary: MBTextSummary) -> Self {
 854        TextSummary {
 855            len: summary.len.0,
 856            chars: summary.chars,
 857            len_utf16: summary.len_utf16,
 858            lines: summary.lines,
 859            first_line_chars: summary.first_line_chars,
 860            last_line_chars: summary.last_line_chars,
 861            last_line_len_utf16: summary.last_line_len_utf16,
 862            longest_row: summary.longest_row,
 863            longest_row_chars: summary.longest_row_chars,
 864        }
 865    }
 866}
 867
 868impl From<&str> for MBTextSummary {
 869    fn from(text: &str) -> Self {
 870        MBTextSummary::from(TextSummary::from(text))
 871    }
 872}
 873
 874impl MultiBufferDimension for MBTextSummary {
 875    type TextDimension = TextSummary;
 876
 877    fn from_summary(summary: &MBTextSummary) -> Self {
 878        *summary
 879    }
 880
 881    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 882        *self += *summary;
 883    }
 884
 885    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 886        *self += *summary;
 887    }
 888}
 889
 890impl AddAssign for MBTextSummary {
 891    fn add_assign(&mut self, other: MBTextSummary) {
 892        let joined_chars = self.last_line_chars + other.first_line_chars;
 893        if joined_chars > self.longest_row_chars {
 894            self.longest_row = self.lines.row;
 895            self.longest_row_chars = joined_chars;
 896        }
 897        if other.longest_row_chars > self.longest_row_chars {
 898            self.longest_row = self.lines.row + other.longest_row;
 899            self.longest_row_chars = other.longest_row_chars;
 900        }
 901
 902        if self.lines.row == 0 {
 903            self.first_line_chars += other.first_line_chars;
 904        }
 905
 906        if other.lines.row == 0 {
 907            self.last_line_chars += other.first_line_chars;
 908            self.last_line_len_utf16 += other.last_line_len_utf16;
 909        } else {
 910            self.last_line_chars = other.last_line_chars;
 911            self.last_line_len_utf16 = other.last_line_len_utf16;
 912        }
 913
 914        self.chars += other.chars;
 915        self.len += other.len;
 916        self.len_utf16 += other.len_utf16;
 917        self.lines += other.lines;
 918    }
 919}
 920
 921impl AddAssign<TextSummary> for MBTextSummary {
 922    fn add_assign(&mut self, other: TextSummary) {
 923        *self += MBTextSummary::from(other);
 924    }
 925}
 926
 927impl MBTextSummary {
 928    pub fn lines_utf16(&self) -> PointUtf16 {
 929        PointUtf16 {
 930            row: self.lines.row,
 931            column: self.last_line_len_utf16,
 932        }
 933    }
 934}
 935
 936impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 937where
 938    K: MultiBufferDimension,
 939    V: MultiBufferDimension,
 940{
 941    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 942
 943    fn from_summary(summary: &MBTextSummary) -> Self {
 944        Self {
 945            key: K::from_summary(summary),
 946            value: Some(V::from_summary(summary)),
 947        }
 948    }
 949
 950    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 951        self.key.add_text_dim(&summary.key);
 952        if let Some(value) = &mut self.value {
 953            if let Some(other_value) = summary.value.as_ref() {
 954                value.add_text_dim(other_value);
 955            }
 956        }
 957    }
 958
 959    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 960        self.key.add_mb_text_summary(summary);
 961        if let Some(value) = &mut self.value {
 962            value.add_mb_text_summary(summary);
 963        }
 964    }
 965}
 966
 967#[derive(Clone)]
 968pub struct MultiBufferRows<'a> {
 969    point: Point,
 970    is_empty: bool,
 971    is_singleton: bool,
 972    cursor: MultiBufferCursor<'a, Point, Point>,
 973}
 974
 975pub struct MultiBufferChunks<'a> {
 976    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 977    diff_transforms:
 978        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 979    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 980    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 981    buffer_chunk: Option<Chunk<'a>>,
 982    range: Range<MultiBufferOffset>,
 983    excerpt_offset_range: Range<ExcerptOffset>,
 984    excerpt_chunks: Option<ExcerptChunks<'a>>,
 985    language_aware: bool,
 986}
 987
 988pub struct ReversedMultiBufferChunks<'a> {
 989    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 990    current_chunks: Option<rope::Chunks<'a>>,
 991    start: MultiBufferOffset,
 992    offset: MultiBufferOffset,
 993}
 994
 995pub struct MultiBufferBytes<'a> {
 996    range: Range<MultiBufferOffset>,
 997    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 998    excerpt_bytes: Option<text::Bytes<'a>>,
 999    has_trailing_newline: bool,
1000    chunk: &'a [u8],
1001}
1002
1003pub struct ReversedMultiBufferBytes<'a> {
1004    range: Range<MultiBufferOffset>,
1005    chunks: ReversedMultiBufferChunks<'a>,
1006    chunk: &'a [u8],
1007}
1008
1009#[derive(Clone)]
1010struct DiffTransforms<MBD> {
1011    output_dimension: OutputDimension<MBD>,
1012    excerpt_dimension: ExcerptDimension<MBD>,
1013}
1014
1015impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1016    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1017        Self {
1018            output_dimension: OutputDimension::zero(cx),
1019            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1020                cx,
1021            ),
1022        }
1023    }
1024
1025    fn add_summary(
1026        &mut self,
1027        summary: &'a DiffTransformSummary,
1028        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1029    ) {
1030        self.output_dimension.add_summary(summary, cx);
1031        self.excerpt_dimension.add_summary(summary, cx);
1032    }
1033}
1034
1035#[derive(Clone)]
1036struct MultiBufferCursor<'a, MBD, BD> {
1037    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1038    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1039    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1040    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1041}
1042
1043#[derive(Clone)]
1044struct MultiBufferRegion<'a, MBD, BD> {
1045    buffer: &'a BufferSnapshot,
1046    is_main_buffer: bool,
1047    diff_hunk_status: Option<DiffHunkStatus>,
1048    excerpt: &'a Excerpt,
1049    buffer_range: Range<BD>,
1050    range: Range<MBD>,
1051    has_trailing_newline: bool,
1052}
1053
1054struct ExcerptChunks<'a> {
1055    excerpt_id: ExcerptId,
1056    content_chunks: BufferChunks<'a>,
1057    has_footer: bool,
1058}
1059
1060#[derive(Debug)]
1061struct BufferEdit {
1062    range: Range<BufferOffset>,
1063    new_text: Arc<str>,
1064    is_insertion: bool,
1065    original_indent_column: Option<u32>,
1066    excerpt_id: ExcerptId,
1067}
1068
1069#[derive(Clone, Copy, Debug, PartialEq)]
1070enum DiffChangeKind {
1071    BufferEdited,
1072    DiffUpdated { base_changed: bool },
1073    ExpandOrCollapseHunks { expand: bool },
1074}
1075
1076#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1077pub enum ExpandExcerptDirection {
1078    Up,
1079    Down,
1080    UpAndDown,
1081}
1082
1083impl ExpandExcerptDirection {
1084    pub fn should_expand_up(&self) -> bool {
1085        match self {
1086            ExpandExcerptDirection::Up => true,
1087            ExpandExcerptDirection::Down => false,
1088            ExpandExcerptDirection::UpAndDown => true,
1089        }
1090    }
1091
1092    pub fn should_expand_down(&self) -> bool {
1093        match self {
1094            ExpandExcerptDirection::Up => false,
1095            ExpandExcerptDirection::Down => true,
1096            ExpandExcerptDirection::UpAndDown => true,
1097        }
1098    }
1099}
1100
1101#[derive(Clone, Debug, PartialEq)]
1102pub struct IndentGuide {
1103    pub buffer_id: BufferId,
1104    pub start_row: MultiBufferRow,
1105    pub end_row: MultiBufferRow,
1106    pub depth: u32,
1107    pub tab_size: u32,
1108    pub settings: IndentGuideSettings,
1109}
1110
1111impl IndentGuide {
1112    pub fn indent_level(&self) -> u32 {
1113        self.depth * self.tab_size
1114    }
1115}
1116
1117impl MultiBuffer {
1118    pub fn new(capability: Capability) -> Self {
1119        Self::new_(
1120            capability,
1121            MultiBufferSnapshot {
1122                show_headers: true,
1123                show_deleted_hunks: true,
1124                ..MultiBufferSnapshot::default()
1125            },
1126        )
1127    }
1128
1129    pub fn without_headers(capability: Capability) -> Self {
1130        Self::new_(
1131            capability,
1132            MultiBufferSnapshot {
1133                show_deleted_hunks: true,
1134                ..MultiBufferSnapshot::default()
1135            },
1136        )
1137    }
1138
1139    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1140        let mut this = Self::new_(
1141            buffer.read(cx).capability(),
1142            MultiBufferSnapshot {
1143                singleton: true,
1144                show_deleted_hunks: true,
1145                ..MultiBufferSnapshot::default()
1146            },
1147        );
1148        this.singleton = true;
1149        let buffer_id = buffer.read(cx).remote_id();
1150        this.push_excerpts(
1151            buffer,
1152            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1153                buffer_id,
1154            ))],
1155            cx,
1156        );
1157        this
1158    }
1159
1160    #[inline]
1161    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1162        Self {
1163            snapshot: RefCell::new(snapshot),
1164            buffers: Default::default(),
1165            diffs: HashMap::default(),
1166            subscriptions: Topic::default(),
1167            singleton: false,
1168            capability,
1169            title: None,
1170            excerpts_by_path: Default::default(),
1171            paths_by_excerpt: Default::default(),
1172            buffer_changed_since_sync: Default::default(),
1173            history: History::default(),
1174        }
1175    }
1176
1177    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1178        let mut buffers = BTreeMap::default();
1179        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1180        for (buffer_id, buffer_state) in self.buffers.iter() {
1181            buffer_state.buffer.update(new_cx, |buffer, _| {
1182                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1183            });
1184            buffers.insert(
1185                *buffer_id,
1186                BufferState {
1187                    buffer: buffer_state.buffer.clone(),
1188                    last_version: buffer_state.last_version.clone(),
1189                    last_non_text_state_update_count: buffer_state
1190                        .last_non_text_state_update_count
1191                        .clone(),
1192                    excerpts: buffer_state.excerpts.clone(),
1193                    _subscriptions: [
1194                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1195                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1196                    ],
1197                },
1198            );
1199        }
1200        let mut diff_bases = HashMap::default();
1201        for (buffer_id, diff) in self.diffs.iter() {
1202            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1203        }
1204        Self {
1205            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1206            buffers,
1207            excerpts_by_path: Default::default(),
1208            paths_by_excerpt: Default::default(),
1209            diffs: diff_bases,
1210            subscriptions: Default::default(),
1211            singleton: self.singleton,
1212            capability: self.capability,
1213            history: self.history.clone(),
1214            title: self.title.clone(),
1215            buffer_changed_since_sync,
1216        }
1217    }
1218
1219    pub fn set_group_interval(&mut self, group_interval: Duration) {
1220        self.history.set_group_interval(group_interval);
1221    }
1222
1223    pub fn with_title(mut self, title: String) -> Self {
1224        self.title = Some(title);
1225        self
1226    }
1227
1228    pub fn read_only(&self) -> bool {
1229        !self.capability.editable()
1230    }
1231
1232    pub fn capability(&self) -> Capability {
1233        self.capability
1234    }
1235
1236    /// Returns an up-to-date snapshot of the MultiBuffer.
1237    #[ztracing::instrument(skip_all)]
1238    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1239        self.sync(cx);
1240        self.snapshot.borrow().clone()
1241    }
1242
1243    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1244        self.sync(cx);
1245        self.snapshot.borrow()
1246    }
1247
1248    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1249        if self.singleton {
1250            Some(self.buffers.values().next().unwrap().buffer.clone())
1251        } else {
1252            None
1253        }
1254    }
1255
1256    pub fn is_singleton(&self) -> bool {
1257        self.singleton
1258    }
1259
1260    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1261        self.subscriptions.subscribe()
1262    }
1263
1264    pub fn is_dirty(&self, cx: &App) -> bool {
1265        self.read(cx).is_dirty()
1266    }
1267
1268    pub fn has_deleted_file(&self, cx: &App) -> bool {
1269        self.read(cx).has_deleted_file()
1270    }
1271
1272    pub fn has_conflict(&self, cx: &App) -> bool {
1273        self.read(cx).has_conflict()
1274    }
1275
1276    // The `is_empty` signature doesn't match what clippy expects
1277    #[allow(clippy::len_without_is_empty)]
1278    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1279        self.read(cx).len()
1280    }
1281
1282    pub fn is_empty(&self) -> bool {
1283        self.buffers.is_empty()
1284    }
1285
1286    pub fn edit<I, S, T>(
1287        &mut self,
1288        edits: I,
1289        autoindent_mode: Option<AutoindentMode>,
1290        cx: &mut Context<Self>,
1291    ) where
1292        I: IntoIterator<Item = (Range<S>, T)>,
1293        S: ToOffset,
1294        T: Into<Arc<str>>,
1295    {
1296        self.edit_internal(edits, autoindent_mode, true, cx);
1297    }
1298
1299    pub fn edit_non_coalesce<I, S, T>(
1300        &mut self,
1301        edits: I,
1302        autoindent_mode: Option<AutoindentMode>,
1303        cx: &mut Context<Self>,
1304    ) where
1305        I: IntoIterator<Item = (Range<S>, T)>,
1306        S: ToOffset,
1307        T: Into<Arc<str>>,
1308    {
1309        self.edit_internal(edits, autoindent_mode, false, cx);
1310    }
1311
1312    fn edit_internal<I, S, T>(
1313        &mut self,
1314        edits: I,
1315        autoindent_mode: Option<AutoindentMode>,
1316        coalesce_adjacent: bool,
1317        cx: &mut Context<Self>,
1318    ) where
1319        I: IntoIterator<Item = (Range<S>, T)>,
1320        S: ToOffset,
1321        T: Into<Arc<str>>,
1322    {
1323        if self.read_only() || self.buffers.is_empty() {
1324            return;
1325        }
1326        self.sync_mut(cx);
1327        let edits = edits
1328            .into_iter()
1329            .map(|(range, new_text)| {
1330                let mut range = range.start.to_offset(self.snapshot.get_mut())
1331                    ..range.end.to_offset(self.snapshot.get_mut());
1332                if range.start > range.end {
1333                    mem::swap(&mut range.start, &mut range.end);
1334                }
1335                (range, new_text.into())
1336            })
1337            .collect::<Vec<_>>();
1338
1339        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1340
1341        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1342        fn edit_internal(
1343            this: &mut MultiBuffer,
1344            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1345            mut autoindent_mode: Option<AutoindentMode>,
1346            coalesce_adjacent: bool,
1347            cx: &mut Context<MultiBuffer>,
1348        ) {
1349            let original_indent_columns = match &mut autoindent_mode {
1350                Some(AutoindentMode::Block {
1351                    original_indent_columns,
1352                }) => mem::take(original_indent_columns),
1353                _ => Default::default(),
1354            };
1355
1356            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1357                edits,
1358                this.snapshot.get_mut(),
1359                &original_indent_columns,
1360            );
1361
1362            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1363            for (buffer_id, mut edits) in buffer_edits {
1364                buffer_ids.push(buffer_id);
1365                edits.sort_by_key(|edit| edit.range.start);
1366                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1367                    let mut edits = edits.into_iter().peekable();
1368                    let mut insertions = Vec::new();
1369                    let mut original_indent_columns = Vec::new();
1370                    let mut deletions = Vec::new();
1371                    let empty_str: Arc<str> = Arc::default();
1372                    while let Some(BufferEdit {
1373                        mut range,
1374                        mut new_text,
1375                        mut is_insertion,
1376                        original_indent_column,
1377                        excerpt_id,
1378                    }) = edits.next()
1379                    {
1380                        while let Some(BufferEdit {
1381                            range: next_range,
1382                            is_insertion: next_is_insertion,
1383                            new_text: next_new_text,
1384                            excerpt_id: next_excerpt_id,
1385                            ..
1386                        }) = edits.peek()
1387                        {
1388                            let should_coalesce = if coalesce_adjacent {
1389                                range.end >= next_range.start
1390                            } else {
1391                                range.end > next_range.start
1392                            };
1393
1394                            if should_coalesce {
1395                                range.end = cmp::max(next_range.end, range.end);
1396                                is_insertion |= *next_is_insertion;
1397                                if excerpt_id == *next_excerpt_id {
1398                                    new_text = format!("{new_text}{next_new_text}").into();
1399                                }
1400                                edits.next();
1401                            } else {
1402                                break;
1403                            }
1404                        }
1405
1406                        if is_insertion {
1407                            original_indent_columns.push(original_indent_column);
1408                            insertions.push((
1409                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1410                                new_text.clone(),
1411                            ));
1412                        } else if !range.is_empty() {
1413                            deletions.push((
1414                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1415                                empty_str.clone(),
1416                            ));
1417                        }
1418                    }
1419
1420                    let deletion_autoindent_mode =
1421                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1422                            Some(AutoindentMode::Block {
1423                                original_indent_columns: Default::default(),
1424                            })
1425                        } else {
1426                            autoindent_mode.clone()
1427                        };
1428                    let insertion_autoindent_mode =
1429                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1430                            Some(AutoindentMode::Block {
1431                                original_indent_columns,
1432                            })
1433                        } else {
1434                            autoindent_mode.clone()
1435                        };
1436
1437                    if coalesce_adjacent {
1438                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1439                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1440                    } else {
1441                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1442                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1443                    }
1444                })
1445            }
1446
1447            cx.emit(Event::ExcerptsEdited {
1448                excerpt_ids: edited_excerpt_ids,
1449                buffer_ids,
1450            });
1451        }
1452    }
1453
1454    fn convert_edits_to_buffer_edits(
1455        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1456        snapshot: &MultiBufferSnapshot,
1457        original_indent_columns: &[Option<u32>],
1458    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1459        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1460        let mut edited_excerpt_ids = Vec::new();
1461        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1462        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1463            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1464
1465            cursor.seek(&range.start);
1466            let mut start_region = cursor.region().expect("start offset out of bounds");
1467            if !start_region.is_main_buffer {
1468                cursor.next();
1469                if let Some(region) = cursor.region() {
1470                    start_region = region;
1471                } else {
1472                    continue;
1473                }
1474            }
1475
1476            if range.end < start_region.range.start {
1477                continue;
1478            }
1479
1480            let start_region = start_region.clone();
1481            if range.end > start_region.range.end {
1482                cursor.seek_forward(&range.end);
1483            }
1484            let mut end_region = cursor.region().expect("end offset out of bounds");
1485            if !end_region.is_main_buffer {
1486                cursor.prev();
1487                if let Some(region) = cursor.region() {
1488                    end_region = region;
1489                } else {
1490                    continue;
1491                }
1492            }
1493
1494            if range.start > end_region.range.end {
1495                continue;
1496            }
1497
1498            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1499            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1500            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1501                .min(start_region.buffer_range.end);
1502            let buffer_end =
1503                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1504
1505            if start_region.excerpt.id == end_region.excerpt.id {
1506                if start_region.buffer.capability == Capability::ReadWrite
1507                    && start_region.is_main_buffer
1508                {
1509                    edited_excerpt_ids.push(start_region.excerpt.id);
1510                    buffer_edits
1511                        .entry(start_region.buffer.remote_id())
1512                        .or_default()
1513                        .push(BufferEdit {
1514                            range: buffer_start..buffer_end,
1515                            new_text,
1516                            is_insertion: true,
1517                            original_indent_column,
1518                            excerpt_id: start_region.excerpt.id,
1519                        });
1520                }
1521            } else {
1522                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1523                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1524                if start_region.buffer.capability == Capability::ReadWrite
1525                    && start_region.is_main_buffer
1526                {
1527                    edited_excerpt_ids.push(start_region.excerpt.id);
1528                    buffer_edits
1529                        .entry(start_region.buffer.remote_id())
1530                        .or_default()
1531                        .push(BufferEdit {
1532                            range: start_excerpt_range,
1533                            new_text: new_text.clone(),
1534                            is_insertion: true,
1535                            original_indent_column,
1536                            excerpt_id: start_region.excerpt.id,
1537                        });
1538                }
1539                let excerpt_id = end_region.excerpt.id;
1540                if end_region.buffer.capability == Capability::ReadWrite
1541                    && end_region.is_main_buffer
1542                {
1543                    edited_excerpt_ids.push(excerpt_id);
1544                    buffer_edits
1545                        .entry(end_region.buffer.remote_id())
1546                        .or_default()
1547                        .push(BufferEdit {
1548                            range: end_excerpt_range,
1549                            new_text: new_text.clone(),
1550                            is_insertion: false,
1551                            original_indent_column,
1552                            excerpt_id,
1553                        });
1554                }
1555
1556                cursor.seek(&range.start);
1557                cursor.next_excerpt();
1558                while let Some(region) = cursor.region() {
1559                    if region.excerpt.id == excerpt_id {
1560                        break;
1561                    }
1562                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1563                        edited_excerpt_ids.push(region.excerpt.id);
1564                        buffer_edits
1565                            .entry(region.buffer.remote_id())
1566                            .or_default()
1567                            .push(BufferEdit {
1568                                range: region.buffer_range.clone(),
1569                                new_text: new_text.clone(),
1570                                is_insertion: false,
1571                                original_indent_column,
1572                                excerpt_id: region.excerpt.id,
1573                            });
1574                    }
1575                    cursor.next_excerpt();
1576                }
1577            }
1578        }
1579        (buffer_edits, edited_excerpt_ids)
1580    }
1581
1582    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1583    where
1584        I: IntoIterator<Item = Range<S>>,
1585        S: ToOffset,
1586    {
1587        if self.read_only() || self.buffers.is_empty() {
1588            return;
1589        }
1590        self.sync_mut(cx);
1591        let empty = Arc::<str>::from("");
1592        let edits = ranges
1593            .into_iter()
1594            .map(|range| {
1595                let mut range = range.start.to_offset(self.snapshot.get_mut())
1596                    ..range.end.to_offset(&self.snapshot.get_mut());
1597                if range.start > range.end {
1598                    mem::swap(&mut range.start, &mut range.end);
1599                }
1600                (range, empty.clone())
1601            })
1602            .collect::<Vec<_>>();
1603
1604        return autoindent_ranges_internal(self, edits, cx);
1605
1606        fn autoindent_ranges_internal(
1607            this: &mut MultiBuffer,
1608            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1609            cx: &mut Context<MultiBuffer>,
1610        ) {
1611            let (buffer_edits, edited_excerpt_ids) =
1612                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1613
1614            let mut buffer_ids = Vec::new();
1615            for (buffer_id, mut edits) in buffer_edits {
1616                buffer_ids.push(buffer_id);
1617                edits.sort_unstable_by_key(|edit| edit.range.start);
1618
1619                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1620                for edit in edits {
1621                    if let Some(last_range) = ranges.last_mut()
1622                        && edit.range.start <= last_range.end
1623                    {
1624                        last_range.end = last_range.end.max(edit.range.end);
1625                        continue;
1626                    }
1627                    ranges.push(edit.range);
1628                }
1629
1630                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1631                    buffer.autoindent_ranges(ranges, cx);
1632                })
1633            }
1634
1635            cx.emit(Event::ExcerptsEdited {
1636                excerpt_ids: edited_excerpt_ids,
1637                buffer_ids,
1638            });
1639        }
1640    }
1641
1642    pub fn set_active_selections(
1643        &self,
1644        selections: &[Selection<Anchor>],
1645        line_mode: bool,
1646        cursor_shape: CursorShape,
1647        cx: &mut Context<Self>,
1648    ) {
1649        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1650            Default::default();
1651        let snapshot = self.read(cx);
1652        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1653        for selection in selections {
1654            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1655            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1656
1657            cursor.seek(&Some(start_locator), Bias::Left);
1658            while let Some(excerpt) = cursor.item()
1659                && excerpt.locator <= *end_locator
1660            {
1661                let mut start = excerpt.range.context.start;
1662                let mut end = excerpt.range.context.end;
1663                if excerpt.id == selection.start.excerpt_id {
1664                    start = selection.start.text_anchor;
1665                }
1666                if excerpt.id == selection.end.excerpt_id {
1667                    end = selection.end.text_anchor;
1668                }
1669                selections_by_buffer
1670                    .entry(excerpt.buffer_id)
1671                    .or_default()
1672                    .push(Selection {
1673                        id: selection.id,
1674                        start,
1675                        end,
1676                        reversed: selection.reversed,
1677                        goal: selection.goal,
1678                    });
1679
1680                cursor.next();
1681            }
1682        }
1683
1684        for (buffer_id, buffer_state) in self.buffers.iter() {
1685            if !selections_by_buffer.contains_key(buffer_id) {
1686                buffer_state
1687                    .buffer
1688                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1689            }
1690        }
1691
1692        for (buffer_id, mut selections) in selections_by_buffer {
1693            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1694                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1695                let mut selections = selections.into_iter().peekable();
1696                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1697                    let mut selection = selections.next()?;
1698                    while let Some(next_selection) = selections.peek() {
1699                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1700                            let next_selection = selections.next().unwrap();
1701                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1702                                selection.end = next_selection.end;
1703                            }
1704                        } else {
1705                            break;
1706                        }
1707                    }
1708                    Some(selection)
1709                }));
1710                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1711            });
1712        }
1713    }
1714
1715    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1716        for buffer in self.buffers.values() {
1717            buffer
1718                .buffer
1719                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1720        }
1721    }
1722
1723    pub fn push_excerpts<O>(
1724        &mut self,
1725        buffer: Entity<Buffer>,
1726        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1727        cx: &mut Context<Self>,
1728    ) -> Vec<ExcerptId>
1729    where
1730        O: text::ToOffset,
1731    {
1732        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1733    }
1734
1735    #[instrument(skip_all)]
1736    fn merge_excerpt_ranges<'a>(
1737        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1738    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1739        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1740        let mut counts: Vec<usize> = Vec::new();
1741        for range in expanded_ranges {
1742            if let Some(last_range) = merged_ranges.last_mut() {
1743                assert!(
1744                    last_range.context.start <= range.context.start,
1745                    "ranges must be sorted: {last_range:?} <= {range:?}"
1746                );
1747                if last_range.context.end >= range.context.start
1748                    || last_range.context.end.row + 1 == range.context.start.row
1749                {
1750                    last_range.context.end = range.context.end.max(last_range.context.end);
1751                    *counts.last_mut().unwrap() += 1;
1752                    continue;
1753                }
1754            }
1755            merged_ranges.push(range.clone());
1756            counts.push(1);
1757        }
1758        (merged_ranges, counts)
1759    }
1760
1761    pub fn insert_excerpts_after<O>(
1762        &mut self,
1763        prev_excerpt_id: ExcerptId,
1764        buffer: Entity<Buffer>,
1765        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1766        cx: &mut Context<Self>,
1767    ) -> Vec<ExcerptId>
1768    where
1769        O: text::ToOffset,
1770    {
1771        let mut ids = Vec::new();
1772        let mut next_excerpt_id =
1773            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1774                last_entry.id.0 + 1
1775            } else {
1776                1
1777            };
1778        self.insert_excerpts_with_ids_after(
1779            prev_excerpt_id,
1780            buffer,
1781            ranges.into_iter().map(|range| {
1782                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1783                ids.push(id);
1784                (id, range)
1785            }),
1786            cx,
1787        );
1788        ids
1789    }
1790
1791    pub fn insert_excerpts_with_ids_after<O>(
1792        &mut self,
1793        prev_excerpt_id: ExcerptId,
1794        buffer: Entity<Buffer>,
1795        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1796        cx: &mut Context<Self>,
1797    ) where
1798        O: text::ToOffset,
1799    {
1800        assert_eq!(self.history.transaction_depth(), 0);
1801        let mut ranges = ranges.into_iter().peekable();
1802        if ranges.peek().is_none() {
1803            return Default::default();
1804        }
1805
1806        self.sync_mut(cx);
1807
1808        let buffer_snapshot = buffer.read(cx).snapshot();
1809        let buffer_id = buffer_snapshot.remote_id();
1810
1811        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1812            self.buffer_changed_since_sync.replace(true);
1813            buffer.update(cx, |buffer, _| {
1814                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1815            });
1816            BufferState {
1817                last_version: RefCell::new(buffer_snapshot.version().clone()),
1818                last_non_text_state_update_count: Cell::new(
1819                    buffer_snapshot.non_text_state_update_count(),
1820                ),
1821                excerpts: Default::default(),
1822                _subscriptions: [
1823                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1824                    cx.subscribe(&buffer, Self::on_buffer_event),
1825                ],
1826                buffer: buffer.clone(),
1827            }
1828        });
1829
1830        let mut snapshot = self.snapshot.get_mut();
1831
1832        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1833        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1834        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1835        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1836        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1837
1838        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1839        new_excerpts.update_last(
1840            |excerpt| {
1841                excerpt.has_trailing_newline = true;
1842            },
1843            (),
1844        );
1845
1846        let next_locator = if let Some(excerpt) = cursor.item() {
1847            excerpt.locator.clone()
1848        } else {
1849            Locator::max()
1850        };
1851
1852        let mut excerpts = Vec::new();
1853        let buffer_snapshot = Arc::new(buffer_snapshot);
1854        while let Some((id, range)) = ranges.next() {
1855            let locator = Locator::between(&prev_locator, &next_locator);
1856            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1857                buffer_state.excerpts.insert(ix, locator.clone());
1858            }
1859            let range = ExcerptRange {
1860                context: buffer_snapshot.anchor_before(&range.context.start)
1861                    ..buffer_snapshot.anchor_after(&range.context.end),
1862                primary: buffer_snapshot.anchor_before(&range.primary.start)
1863                    ..buffer_snapshot.anchor_after(&range.primary.end),
1864            };
1865            excerpts.push((id, range.clone()));
1866            let excerpt = Excerpt::new(
1867                id,
1868                locator.clone(),
1869                buffer_id,
1870                buffer_snapshot.clone(),
1871                range,
1872                ranges.peek().is_some() || cursor.item().is_some(),
1873            );
1874            new_excerpts.push(excerpt, ());
1875            prev_locator = locator.clone();
1876
1877            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1878                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1879            }
1880            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1881        }
1882        snapshot
1883            .buffer_locators
1884            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1885
1886        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1887
1888        let suffix = cursor.suffix();
1889        let changed_trailing_excerpt = suffix.is_empty();
1890        new_excerpts.append(suffix, ());
1891        drop(cursor);
1892        snapshot.excerpts = new_excerpts;
1893        snapshot.excerpt_ids = new_excerpt_ids;
1894        if changed_trailing_excerpt {
1895            snapshot.trailing_excerpt_update_count += 1;
1896        }
1897
1898        let edits = Self::sync_diff_transforms(
1899            &mut snapshot,
1900            vec![Edit {
1901                old: edit_start..edit_start,
1902                new: edit_start..edit_end,
1903            }],
1904            DiffChangeKind::BufferEdited,
1905        );
1906        if !edits.is_empty() {
1907            self.subscriptions.publish(edits);
1908        }
1909
1910        cx.emit(Event::Edited {
1911            edited_buffer: None,
1912        });
1913        cx.emit(Event::ExcerptsAdded {
1914            buffer,
1915            predecessor: prev_excerpt_id,
1916            excerpts,
1917        });
1918        cx.notify();
1919    }
1920
1921    pub fn clear(&mut self, cx: &mut Context<Self>) {
1922        self.sync_mut(cx);
1923        let ids = self.excerpt_ids();
1924        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1925        self.excerpts_by_path.clear();
1926        self.paths_by_excerpt.clear();
1927        let MultiBufferSnapshot {
1928            excerpts,
1929            buffer_locators,
1930            diffs: _,
1931            diff_transforms: _,
1932            non_text_state_update_count: _,
1933            edit_count: _,
1934            is_dirty,
1935            has_deleted_file,
1936            has_conflict,
1937            has_inverted_diff,
1938            singleton: _,
1939            excerpt_ids: _,
1940            replaced_excerpts,
1941            trailing_excerpt_update_count,
1942            all_diff_hunks_expanded: _,
1943            show_deleted_hunks: _,
1944            use_extended_diff_range: _,
1945            show_headers: _,
1946        } = self.snapshot.get_mut();
1947        buffer_locators.clear();
1948        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1949        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1950        *excerpts = Default::default();
1951        *trailing_excerpt_update_count += 1;
1952        *is_dirty = false;
1953        *has_deleted_file = false;
1954        *has_conflict = false;
1955        *has_inverted_diff = false;
1956        replaced_excerpts.clear();
1957
1958        let edits = Self::sync_diff_transforms(
1959            self.snapshot.get_mut(),
1960            vec![Edit {
1961                old: start..prev_len,
1962                new: start..start,
1963            }],
1964            DiffChangeKind::BufferEdited,
1965        );
1966        if !edits.is_empty() {
1967            self.subscriptions.publish(edits);
1968        }
1969        cx.emit(Event::Edited {
1970            edited_buffer: None,
1971        });
1972        cx.emit(Event::ExcerptsRemoved {
1973            ids,
1974            removed_buffer_ids,
1975        });
1976        cx.notify();
1977    }
1978
1979    #[ztracing::instrument(skip_all)]
1980    pub fn excerpts_for_buffer(
1981        &self,
1982        buffer_id: BufferId,
1983        cx: &App,
1984    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1985        let mut excerpts = Vec::new();
1986        let snapshot = self.read(cx);
1987        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1988        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1989            for locator in &**locators {
1990                cursor.seek_forward(&Some(locator), Bias::Left);
1991                if let Some(excerpt) = cursor.item()
1992                    && excerpt.locator == *locator
1993                {
1994                    excerpts.push((excerpt.id, excerpt.range.clone()));
1995                }
1996            }
1997        }
1998
1999        excerpts
2000    }
2001
2002    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2003        let snapshot = self.read(cx);
2004        let mut excerpts = snapshot
2005            .excerpts
2006            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2007        let mut diff_transforms = snapshot
2008            .diff_transforms
2009            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2010        diff_transforms.next();
2011        let locators = snapshot
2012            .buffer_locators
2013            .get(&buffer_id)
2014            .into_iter()
2015            .flat_map(|v| &**v);
2016        let mut result = Vec::new();
2017        for locator in locators {
2018            excerpts.seek_forward(&Some(locator), Bias::Left);
2019            if let Some(excerpt) = excerpts.item()
2020                && excerpt.locator == *locator
2021            {
2022                let excerpt_start = excerpts.start().1;
2023                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2024
2025                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2026                let overshoot = excerpt_start - diff_transforms.start().0;
2027                let start = diff_transforms.start().1 + overshoot;
2028
2029                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2030                let overshoot = excerpt_end - diff_transforms.start().0;
2031                let end = diff_transforms.start().1 + overshoot;
2032
2033                result.push(start.0..end.0)
2034            }
2035        }
2036        result
2037    }
2038
2039    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2040        self.snapshot
2041            .borrow()
2042            .excerpts
2043            .iter()
2044            .map(|entry| entry.buffer_id)
2045            .collect()
2046    }
2047
2048    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2049        self.snapshot
2050            .borrow()
2051            .excerpts
2052            .iter()
2053            .map(|entry| entry.id)
2054            .collect()
2055    }
2056
2057    pub fn excerpt_containing(
2058        &self,
2059        position: impl ToOffset,
2060        cx: &App,
2061    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2062        let snapshot = self.read(cx);
2063        let offset = position.to_offset(&snapshot);
2064
2065        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2066        cursor.seek(&offset);
2067        cursor
2068            .excerpt()
2069            .or_else(|| snapshot.excerpts.last())
2070            .map(|excerpt| {
2071                (
2072                    excerpt.id,
2073                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2074                    excerpt.range.context.clone(),
2075                )
2076            })
2077    }
2078
2079    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2080        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2081            self.buffer(buffer_id)
2082        } else {
2083            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2084            Some(buffer)
2085        }
2086    }
2087
2088    // If point is at the end of the buffer, the last excerpt is returned
2089    pub fn point_to_buffer_offset<T: ToOffset>(
2090        &self,
2091        point: T,
2092        cx: &App,
2093    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2094        let snapshot = self.read(cx);
2095        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2096        Some((
2097            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2098            offset,
2099        ))
2100    }
2101
2102    // If point is at the end of the buffer, the last excerpt is returned
2103    pub fn point_to_buffer_point<T: ToPoint>(
2104        &self,
2105        point: T,
2106        cx: &App,
2107    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2108        let snapshot = self.read(cx);
2109        let (buffer, point, is_main_buffer) =
2110            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2111        Some((
2112            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2113            point,
2114            is_main_buffer,
2115        ))
2116    }
2117
2118    pub fn buffer_point_to_anchor(
2119        &self,
2120        // todo(lw): We shouldn't need this?
2121        buffer: &Entity<Buffer>,
2122        point: Point,
2123        cx: &App,
2124    ) -> Option<Anchor> {
2125        let mut found = None;
2126        let snapshot = buffer.read(cx).snapshot();
2127        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2128            let start = range.context.start.to_point(&snapshot);
2129            let end = range.context.end.to_point(&snapshot);
2130            if start <= point && point < end {
2131                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2132                break;
2133            }
2134            if point < start {
2135                found = Some((start, excerpt_id));
2136            }
2137            if point > end {
2138                found = Some((end, excerpt_id));
2139            }
2140        }
2141
2142        found.map(|(point, excerpt_id)| {
2143            let text_anchor = snapshot.anchor_after(point);
2144            Anchor::in_buffer(excerpt_id, text_anchor)
2145        })
2146    }
2147
2148    pub fn buffer_anchor_to_anchor(
2149        &self,
2150        // todo(lw): We shouldn't need this?
2151        buffer: &Entity<Buffer>,
2152        anchor: text::Anchor,
2153        cx: &App,
2154    ) -> Option<Anchor> {
2155        let snapshot = buffer.read(cx).snapshot();
2156        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2157            if range.context.start.cmp(&anchor, &snapshot).is_le()
2158                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2159            {
2160                return Some(Anchor::in_buffer(excerpt_id, anchor));
2161            }
2162        }
2163
2164        None
2165    }
2166
2167    pub fn merge_excerpts(
2168        &mut self,
2169        excerpt_ids: &[ExcerptId],
2170        cx: &mut Context<Self>,
2171    ) -> ExcerptId {
2172        debug_assert!(!excerpt_ids.is_empty());
2173        if excerpt_ids.len() == 1 {
2174            return excerpt_ids[0];
2175        }
2176
2177        let snapshot = self.snapshot(cx);
2178
2179        let first_range = snapshot
2180            .context_range_for_excerpt(excerpt_ids[0])
2181            .expect("first excerpt must exist");
2182        let last_range = snapshot
2183            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2184            .expect("last excerpt must exist");
2185
2186        let union_range = first_range.start..last_range.end;
2187
2188        drop(snapshot);
2189
2190        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2191        self.remove_excerpts(excerpt_ids[1..].iter().copied(), cx);
2192
2193        excerpt_ids[0]
2194    }
2195
2196    pub fn remove_excerpts(
2197        &mut self,
2198        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2199        cx: &mut Context<Self>,
2200    ) {
2201        self.sync_mut(cx);
2202        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2203        if ids.is_empty() {
2204            return;
2205        }
2206        self.buffer_changed_since_sync.replace(true);
2207
2208        let mut snapshot = self.snapshot.get_mut();
2209        let mut new_excerpts = SumTree::default();
2210        let mut cursor = snapshot
2211            .excerpts
2212            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2213        let mut edits = Vec::new();
2214        let mut excerpt_ids = ids.iter().copied().peekable();
2215        let mut removed_buffer_ids = Vec::new();
2216        let mut removed_excerpts_for_buffers = HashSet::default();
2217
2218        while let Some(excerpt_id) = excerpt_ids.next() {
2219            self.paths_by_excerpt.remove(&excerpt_id);
2220            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2221            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2222            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2223
2224            if let Some(mut excerpt) = cursor.item() {
2225                if excerpt.id != excerpt_id {
2226                    continue;
2227                }
2228                let mut old_start = cursor.start().1;
2229
2230                // Skip over the removed excerpt.
2231                'remove_excerpts: loop {
2232                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2233                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2234                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2235                        if buffer_state.excerpts.is_empty() {
2236                            log::debug!(
2237                                "removing buffer and diff for buffer {}",
2238                                excerpt.buffer_id
2239                            );
2240                            self.buffers.remove(&excerpt.buffer_id);
2241                            removed_buffer_ids.push(excerpt.buffer_id);
2242                        }
2243                    }
2244                    cursor.next();
2245
2246                    // Skip over any subsequent excerpts that are also removed.
2247                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2248                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2249                        if let Some(next_excerpt) = cursor.item()
2250                            && next_excerpt.locator == *next_locator
2251                        {
2252                            excerpt_ids.next();
2253                            excerpt = next_excerpt;
2254                            continue 'remove_excerpts;
2255                        }
2256                    }
2257
2258                    break;
2259                }
2260
2261                // When removing the last excerpt, remove the trailing newline from
2262                // the previous excerpt.
2263                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2264                    old_start -= 1;
2265                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2266                }
2267
2268                // Push an edit for the removal of this run of excerpts.
2269                let old_end = cursor.start().1;
2270                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2271                edits.push(Edit {
2272                    old: old_start..old_end,
2273                    new: new_start..new_start,
2274                });
2275            }
2276        }
2277        let suffix = cursor.suffix();
2278        let changed_trailing_excerpt = suffix.is_empty();
2279        new_excerpts.append(suffix, ());
2280        drop(cursor);
2281        for buffer_id in removed_excerpts_for_buffers {
2282            match self.buffers.get(&buffer_id) {
2283                Some(buffer_state) => {
2284                    snapshot
2285                        .buffer_locators
2286                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2287                }
2288                None => {
2289                    snapshot.buffer_locators.remove(&buffer_id);
2290                }
2291            }
2292        }
2293        snapshot.excerpts = new_excerpts;
2294        for buffer_id in &removed_buffer_ids {
2295            self.diffs.remove(buffer_id);
2296            snapshot.diffs.remove(buffer_id);
2297        }
2298
2299        // Recalculate has_inverted_diff after removing diffs
2300        if !removed_buffer_ids.is_empty() {
2301            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2302        }
2303
2304        if changed_trailing_excerpt {
2305            snapshot.trailing_excerpt_update_count += 1;
2306        }
2307
2308        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2309        if !edits.is_empty() {
2310            self.subscriptions.publish(edits);
2311        }
2312        cx.emit(Event::Edited {
2313            edited_buffer: None,
2314        });
2315        cx.emit(Event::ExcerptsRemoved {
2316            ids,
2317            removed_buffer_ids,
2318        });
2319        cx.notify();
2320    }
2321
2322    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2323        &self,
2324        anchors: Anchors,
2325        cx: &mut Context<Self>,
2326    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2327        let mut error = None;
2328        let mut futures = Vec::new();
2329        for anchor in anchors {
2330            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2331                if let Some(buffer) = self.buffers.get(&buffer_id) {
2332                    buffer.buffer.update(cx, |buffer, _| {
2333                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2334                    });
2335                } else {
2336                    error = Some(anyhow!(
2337                        "buffer {buffer_id} is not part of this multi-buffer"
2338                    ));
2339                    break;
2340                }
2341            }
2342        }
2343        async move {
2344            if let Some(error) = error {
2345                Err(error)?;
2346            }
2347            for future in futures {
2348                future.await?;
2349            }
2350            Ok(())
2351        }
2352    }
2353
2354    pub fn text_anchor_for_position<T: ToOffset>(
2355        &self,
2356        position: T,
2357        cx: &App,
2358    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2359        let snapshot = self.read(cx);
2360        let anchor = snapshot.anchor_before(position);
2361        let buffer = self
2362            .buffers
2363            .get(&anchor.text_anchor.buffer_id?)?
2364            .buffer
2365            .clone();
2366        Some((buffer, anchor.text_anchor))
2367    }
2368
2369    fn on_buffer_event(
2370        &mut self,
2371        buffer: Entity<Buffer>,
2372        event: &language::BufferEvent,
2373        cx: &mut Context<Self>,
2374    ) {
2375        use language::BufferEvent;
2376        let buffer_id = buffer.read(cx).remote_id();
2377        cx.emit(match event {
2378            BufferEvent::Edited => Event::Edited {
2379                edited_buffer: Some(buffer),
2380            },
2381            BufferEvent::DirtyChanged => Event::DirtyChanged,
2382            BufferEvent::Saved => Event::Saved,
2383            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2384            BufferEvent::Reloaded => Event::Reloaded,
2385            BufferEvent::LanguageChanged(has_language) => {
2386                Event::LanguageChanged(buffer_id, *has_language)
2387            }
2388            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2389            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2390            BufferEvent::CapabilityChanged => {
2391                self.capability = buffer.read(cx).capability();
2392                return;
2393            }
2394            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2395        });
2396    }
2397
2398    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2399        let diff = diff.read(cx);
2400        let buffer_id = diff.buffer_id;
2401        let diff = DiffStateSnapshot {
2402            diff: diff.snapshot(cx),
2403            is_inverted: false,
2404        };
2405        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2406    }
2407
2408    fn inverted_buffer_diff_language_changed(
2409        &mut self,
2410        diff: Entity<BufferDiff>,
2411        cx: &mut Context<Self>,
2412    ) {
2413        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2414        let diff = diff.read(cx);
2415        let diff = DiffStateSnapshot {
2416            diff: diff.snapshot(cx),
2417            is_inverted: true,
2418        };
2419        self.snapshot
2420            .get_mut()
2421            .diffs
2422            .insert(base_text_buffer_id, diff);
2423    }
2424
2425    fn buffer_diff_changed(
2426        &mut self,
2427        diff: Entity<BufferDiff>,
2428        range: Range<text::Anchor>,
2429        cx: &mut Context<Self>,
2430    ) {
2431        self.sync_mut(cx);
2432
2433        let diff = diff.read(cx);
2434        let buffer_id = diff.buffer_id;
2435
2436        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2437            return;
2438        };
2439        let new_diff = DiffStateSnapshot {
2440            diff: diff.snapshot(cx),
2441            is_inverted: false,
2442        };
2443        let mut snapshot = self.snapshot.get_mut();
2444        let base_text_changed = snapshot
2445            .diffs
2446            .get(&buffer_id)
2447            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2448        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2449
2450        let buffer = buffer_state.buffer.read(cx);
2451        let diff_change_range = range.to_offset(buffer);
2452
2453        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2454        let edits = Self::sync_diff_transforms(
2455            &mut snapshot,
2456            excerpt_edits,
2457            DiffChangeKind::DiffUpdated {
2458                base_changed: base_text_changed,
2459            },
2460        );
2461        if !edits.is_empty() {
2462            self.subscriptions.publish(edits);
2463        }
2464        cx.emit(Event::Edited {
2465            edited_buffer: None,
2466        });
2467    }
2468
2469    fn inverted_buffer_diff_changed(
2470        &mut self,
2471        diff: Entity<BufferDiff>,
2472        diff_change_range: Range<usize>,
2473        cx: &mut Context<Self>,
2474    ) {
2475        self.sync_mut(cx);
2476
2477        let diff = diff.read(cx);
2478        let base_text_buffer_id = diff.base_text(cx).remote_id();
2479        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2480            return;
2481        };
2482
2483        let new_diff = DiffStateSnapshot {
2484            diff: diff.snapshot(cx),
2485            is_inverted: true,
2486        };
2487        let mut snapshot = self.snapshot.get_mut();
2488        snapshot
2489            .diffs
2490            .insert_or_replace(base_text_buffer_id, new_diff);
2491
2492        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2493        let edits = Self::sync_diff_transforms(
2494            &mut snapshot,
2495            excerpt_edits,
2496            DiffChangeKind::DiffUpdated {
2497                // We don't read this field for inverted diffs.
2498                base_changed: false,
2499            },
2500        );
2501        if !edits.is_empty() {
2502            self.subscriptions.publish(edits);
2503        }
2504        cx.emit(Event::Edited {
2505            edited_buffer: None,
2506        });
2507    }
2508
2509    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2510        self.buffers.values().map(|state| state.buffer.clone())
2511    }
2512
2513    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2514        self.all_buffers_iter().collect()
2515    }
2516
2517    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2518        self.buffers.keys().copied()
2519    }
2520
2521    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2522        self.all_buffer_ids_iter().collect()
2523    }
2524
2525    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2526        self.buffers
2527            .get(&buffer_id)
2528            .map(|state| state.buffer.clone())
2529    }
2530
2531    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2532        self.point_to_buffer_offset(point, cx)
2533            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2534    }
2535
2536    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2537        let buffer_id = self
2538            .snapshot
2539            .borrow()
2540            .excerpts
2541            .first()
2542            .map(|excerpt| excerpt.buffer.remote_id());
2543        buffer_id
2544            .and_then(|buffer_id| self.buffer(buffer_id))
2545            .map(|buffer| {
2546                let buffer = buffer.read(cx);
2547                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2548            })
2549            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2550    }
2551
2552    pub fn language_settings_at<'a, T: ToOffset>(
2553        &'a self,
2554        point: T,
2555        cx: &'a App,
2556    ) -> Cow<'a, LanguageSettings> {
2557        let mut language = None;
2558        let mut file = None;
2559        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2560            let buffer = buffer.read(cx);
2561            language = buffer.language_at(offset);
2562            file = buffer.file();
2563        }
2564        language_settings(language.map(|l| l.name()), file, cx)
2565    }
2566
2567    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2568        self.buffers.values().for_each(|state| f(&state.buffer))
2569    }
2570
2571    pub fn explicit_title(&self) -> Option<&str> {
2572        self.title.as_deref()
2573    }
2574
2575    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2576        if let Some(title) = self.title.as_ref() {
2577            return title.into();
2578        }
2579
2580        if let Some(buffer) = self.as_singleton() {
2581            let buffer = buffer.read(cx);
2582
2583            if let Some(file) = buffer.file() {
2584                return file.file_name(cx).into();
2585            }
2586
2587            if let Some(title) = self.buffer_content_title(buffer) {
2588                return title;
2589            }
2590        };
2591
2592        "untitled".into()
2593    }
2594
2595    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2596        let mut is_leading_whitespace = true;
2597        let mut count = 0;
2598        let mut prev_was_space = false;
2599        let mut title = String::new();
2600
2601        for ch in buffer.snapshot().chars() {
2602            if is_leading_whitespace && ch.is_whitespace() {
2603                continue;
2604            }
2605
2606            is_leading_whitespace = false;
2607
2608            if ch == '\n' || count >= 40 {
2609                break;
2610            }
2611
2612            if ch.is_whitespace() {
2613                if !prev_was_space {
2614                    title.push(' ');
2615                    count += 1;
2616                    prev_was_space = true;
2617                }
2618            } else {
2619                title.push(ch);
2620                count += 1;
2621                prev_was_space = false;
2622            }
2623        }
2624
2625        let title = title.trim_end().to_string();
2626
2627        if title.is_empty() {
2628            return None;
2629        }
2630
2631        Some(title.into())
2632    }
2633
2634    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2635        self.title = Some(title);
2636        cx.notify();
2637    }
2638
2639    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2640    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2641        for buffer_state in self.buffers.values() {
2642            buffer_state
2643                .buffer
2644                .update(cx, |buffer, _cx| buffer.refresh_preview());
2645        }
2646    }
2647
2648    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2649    pub fn preserve_preview(&self, cx: &App) -> bool {
2650        self.buffers
2651            .values()
2652            .all(|state| state.buffer.read(cx).preserve_preview())
2653    }
2654
2655    #[cfg(any(test, feature = "test-support"))]
2656    pub fn is_parsing(&self, cx: &App) -> bool {
2657        self.as_singleton().unwrap().read(cx).is_parsing()
2658    }
2659
2660    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2661        let buffer_id = diff.read(cx).buffer_id;
2662
2663        if let Some(existing_diff) = self.diff_for(buffer_id)
2664            && diff.entity_id() == existing_diff.entity_id()
2665        {
2666            return;
2667        }
2668
2669        self.buffer_diff_changed(
2670            diff.clone(),
2671            text::Anchor::min_max_range_for_buffer(buffer_id),
2672            cx,
2673        );
2674        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2675    }
2676
2677    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2678        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2679        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2680        self.snapshot.get_mut().has_inverted_diff = true;
2681        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2682        self.diffs
2683            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2684    }
2685
2686    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2687        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2688    }
2689
2690    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2691        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2692    }
2693
2694    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2695        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2696    }
2697
2698    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2699        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2700        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2701    }
2702
2703    pub fn all_diff_hunks_expanded(&self) -> bool {
2704        self.snapshot.borrow().all_diff_hunks_expanded
2705    }
2706
2707    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2708        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2709        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2710    }
2711
2712    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2713        self.snapshot.get_mut().show_deleted_hunks = show;
2714        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2715    }
2716
2717    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2718        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2719    }
2720
2721    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2722        self.read(cx)
2723            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2724            .nth(1)
2725            .is_some()
2726    }
2727
2728    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2729        let snapshot = self.read(cx);
2730        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2731        let offset_range = range.to_offset(&snapshot);
2732        cursor.seek(&offset_range.start, Bias::Left);
2733        while let Some(item) = cursor.item() {
2734            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2735                break;
2736            }
2737            if item.hunk_info().is_some() {
2738                return true;
2739            }
2740            cursor.next();
2741        }
2742        false
2743    }
2744
2745    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2746        let snapshot = self.read(cx);
2747        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2748        for range in ranges {
2749            let range = range.to_point(&snapshot);
2750            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2751            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2752                .min(snapshot.len());
2753            cursor.seek(&start, Bias::Right);
2754            while let Some(item) = cursor.item() {
2755                if *cursor.start() >= end {
2756                    break;
2757                }
2758                if item.hunk_info().is_some() {
2759                    return true;
2760                }
2761                cursor.next();
2762            }
2763        }
2764        false
2765    }
2766
2767    pub fn expand_or_collapse_diff_hunks_inner(
2768        &mut self,
2769        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2770        expand: bool,
2771        cx: &mut Context<Self>,
2772    ) {
2773        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2774            return;
2775        }
2776        self.sync_mut(cx);
2777        let mut snapshot = self.snapshot.get_mut();
2778        let mut excerpt_edits = Vec::new();
2779        let mut last_hunk_row = None;
2780        for (range, end_excerpt_id) in ranges {
2781            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2782                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2783                    continue;
2784                }
2785                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2786                    continue;
2787                }
2788                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2789                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2790                let start = snapshot.excerpt_offset_for_anchor(&start);
2791                let end = snapshot.excerpt_offset_for_anchor(&end);
2792                last_hunk_row = Some(diff_hunk.row_range.start);
2793                excerpt_edits.push(text::Edit {
2794                    old: start..end,
2795                    new: start..end,
2796                });
2797            }
2798        }
2799
2800        let edits = Self::sync_diff_transforms(
2801            &mut snapshot,
2802            excerpt_edits,
2803            DiffChangeKind::ExpandOrCollapseHunks { expand },
2804        );
2805        if !edits.is_empty() {
2806            self.subscriptions.publish(edits);
2807        }
2808        cx.emit(Event::DiffHunksToggled);
2809        cx.emit(Event::Edited {
2810            edited_buffer: None,
2811        });
2812    }
2813
2814    pub fn expand_or_collapse_diff_hunks(
2815        &mut self,
2816        ranges: Vec<Range<Anchor>>,
2817        expand: bool,
2818        cx: &mut Context<Self>,
2819    ) {
2820        let snapshot = self.snapshot.borrow().clone();
2821        let ranges = ranges.iter().map(move |range| {
2822            let end_excerpt_id = range.end.excerpt_id;
2823            let range = range.to_point(&snapshot);
2824            let mut peek_end = range.end;
2825            if range.end.row < snapshot.max_row().0 {
2826                peek_end = Point::new(range.end.row + 1, 0);
2827            };
2828            (range.start..peek_end, end_excerpt_id)
2829        });
2830        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2831    }
2832
2833    pub fn resize_excerpt(
2834        &mut self,
2835        id: ExcerptId,
2836        range: Range<text::Anchor>,
2837        cx: &mut Context<Self>,
2838    ) {
2839        self.sync_mut(cx);
2840
2841        let mut snapshot = self.snapshot.get_mut();
2842        let locator = snapshot.excerpt_locator_for_id(id);
2843        let mut new_excerpts = SumTree::default();
2844        let mut cursor = snapshot
2845            .excerpts
2846            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2847        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2848
2849        let prefix = cursor.slice(&Some(locator), Bias::Left);
2850        new_excerpts.append(prefix, ());
2851
2852        let mut excerpt = cursor.item().unwrap().clone();
2853        let old_text_len = excerpt.text_summary.len;
2854
2855        excerpt.range.context.start = range.start;
2856        excerpt.range.context.end = range.end;
2857        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2858
2859        excerpt.text_summary = excerpt
2860            .buffer
2861            .text_summary_for_range(excerpt.range.context.clone());
2862
2863        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2864        let old_start_offset = cursor.start().1;
2865        let new_text_len = excerpt.text_summary.len;
2866        let edit = Edit {
2867            old: old_start_offset..old_start_offset + old_text_len,
2868            new: new_start_offset..new_start_offset + new_text_len,
2869        };
2870
2871        if let Some(last_edit) = edits.last_mut() {
2872            if last_edit.old.end == edit.old.start {
2873                last_edit.old.end = edit.old.end;
2874                last_edit.new.end = edit.new.end;
2875            } else {
2876                edits.push(edit);
2877            }
2878        } else {
2879            edits.push(edit);
2880        }
2881
2882        new_excerpts.push(excerpt, ());
2883
2884        cursor.next();
2885
2886        new_excerpts.append(cursor.suffix(), ());
2887
2888        drop(cursor);
2889        snapshot.excerpts = new_excerpts;
2890
2891        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2892        if !edits.is_empty() {
2893            self.subscriptions.publish(edits);
2894        }
2895        cx.emit(Event::Edited {
2896            edited_buffer: None,
2897        });
2898        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2899        cx.notify();
2900    }
2901
2902    pub fn expand_excerpts(
2903        &mut self,
2904        ids: impl IntoIterator<Item = ExcerptId>,
2905        line_count: u32,
2906        direction: ExpandExcerptDirection,
2907        cx: &mut Context<Self>,
2908    ) {
2909        if line_count == 0 {
2910            return;
2911        }
2912        self.sync_mut(cx);
2913        if !self.excerpts_by_path.is_empty() {
2914            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2915            return;
2916        }
2917        let mut snapshot = self.snapshot.get_mut();
2918
2919        let ids = ids.into_iter().collect::<Vec<_>>();
2920        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2921        let mut new_excerpts = SumTree::default();
2922        let mut cursor = snapshot
2923            .excerpts
2924            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2925        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2926
2927        for locator in &locators {
2928            let prefix = cursor.slice(&Some(locator), Bias::Left);
2929            new_excerpts.append(prefix, ());
2930
2931            let mut excerpt = cursor.item().unwrap().clone();
2932            let old_text_len = excerpt.text_summary.len;
2933
2934            let up_line_count = if direction.should_expand_up() {
2935                line_count
2936            } else {
2937                0
2938            };
2939
2940            let start_row = excerpt
2941                .range
2942                .context
2943                .start
2944                .to_point(&excerpt.buffer)
2945                .row
2946                .saturating_sub(up_line_count);
2947            let start_point = Point::new(start_row, 0);
2948            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2949
2950            let down_line_count = if direction.should_expand_down() {
2951                line_count
2952            } else {
2953                0
2954            };
2955
2956            let mut end_point = excerpt.buffer.clip_point(
2957                excerpt.range.context.end.to_point(&excerpt.buffer)
2958                    + Point::new(down_line_count, 0),
2959                Bias::Left,
2960            );
2961            end_point.column = excerpt.buffer.line_len(end_point.row);
2962            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2963            excerpt.max_buffer_row = end_point.row;
2964
2965            excerpt.text_summary = excerpt
2966                .buffer
2967                .text_summary_for_range(excerpt.range.context.clone());
2968
2969            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2970            let old_start_offset = cursor.start().1;
2971            let new_text_len = excerpt.text_summary.len;
2972            let edit = Edit {
2973                old: old_start_offset..old_start_offset + old_text_len,
2974                new: new_start_offset..new_start_offset + new_text_len,
2975            };
2976
2977            if let Some(last_edit) = edits.last_mut() {
2978                if last_edit.old.end == edit.old.start {
2979                    last_edit.old.end = edit.old.end;
2980                    last_edit.new.end = edit.new.end;
2981                } else {
2982                    edits.push(edit);
2983                }
2984            } else {
2985                edits.push(edit);
2986            }
2987
2988            new_excerpts.push(excerpt, ());
2989
2990            cursor.next();
2991        }
2992
2993        new_excerpts.append(cursor.suffix(), ());
2994
2995        drop(cursor);
2996        snapshot.excerpts = new_excerpts;
2997
2998        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2999        if !edits.is_empty() {
3000            self.subscriptions.publish(edits);
3001        }
3002        cx.emit(Event::Edited {
3003            edited_buffer: None,
3004        });
3005        cx.emit(Event::ExcerptsExpanded { ids });
3006        cx.notify();
3007    }
3008
3009    #[ztracing::instrument(skip_all)]
3010    fn sync(&self, cx: &App) {
3011        let changed = self.buffer_changed_since_sync.replace(false);
3012        if !changed {
3013            return;
3014        }
3015        let edits = Self::sync_from_buffer_changes(
3016            &mut self.snapshot.borrow_mut(),
3017            &self.buffers,
3018            &self.diffs,
3019            cx,
3020        );
3021        if !edits.is_empty() {
3022            self.subscriptions.publish(edits);
3023        }
3024    }
3025
3026    fn sync_mut(&mut self, cx: &App) {
3027        let changed = self.buffer_changed_since_sync.replace(false);
3028        if !changed {
3029            return;
3030        }
3031        let edits =
3032            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3033
3034        if !edits.is_empty() {
3035            self.subscriptions.publish(edits);
3036        }
3037    }
3038
3039    fn sync_from_buffer_changes(
3040        snapshot: &mut MultiBufferSnapshot,
3041        buffers: &BTreeMap<BufferId, BufferState>,
3042        diffs: &HashMap<BufferId, DiffState>,
3043        cx: &App,
3044    ) -> Vec<Edit<MultiBufferOffset>> {
3045        let MultiBufferSnapshot {
3046            excerpts,
3047            buffer_locators: _,
3048            diffs: buffer_diff,
3049            diff_transforms: _,
3050            non_text_state_update_count,
3051            edit_count,
3052            is_dirty,
3053            has_deleted_file,
3054            has_conflict,
3055            has_inverted_diff: _,
3056            singleton: _,
3057            excerpt_ids: _,
3058            replaced_excerpts: _,
3059            trailing_excerpt_update_count: _,
3060            all_diff_hunks_expanded: _,
3061            show_deleted_hunks: _,
3062            use_extended_diff_range: _,
3063            show_headers: _,
3064        } = snapshot;
3065        *is_dirty = false;
3066        *has_deleted_file = false;
3067        *has_conflict = false;
3068
3069        if !diffs.is_empty() {
3070            let mut diffs_to_add = Vec::new();
3071            for (id, diff) in diffs {
3072                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3073                // and use the diff hunk base text ranges to compute diff transforms.
3074                // Those base text ranges are usize, so make sure if the base text changed
3075                // we also update the diff snapshot so that we don't use stale offsets
3076                if buffer_diff.get(id).is_none_or(|existing_diff| {
3077                    if !existing_diff.is_inverted {
3078                        return false;
3079                    }
3080                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3081                    base_text.remote_id() != existing_diff.base_text().remote_id()
3082                        || base_text
3083                            .version()
3084                            .changed_since(existing_diff.base_text().version())
3085                }) {
3086                    if diffs_to_add.capacity() == 0 {
3087                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3088                        // meaning re-allocations will be fairly expensive
3089                        diffs_to_add.reserve(diffs.len());
3090                    }
3091                    diffs_to_add.push((*id, diff.snapshot(cx)));
3092                }
3093            }
3094            buffer_diff.extend(diffs_to_add);
3095        }
3096
3097        let mut excerpts_to_edit = Vec::new();
3098        let mut non_text_state_updated = false;
3099        let mut edited = false;
3100        for buffer_state in buffers.values() {
3101            let buffer = buffer_state.buffer.read(cx);
3102            let version = buffer.version();
3103            let non_text_state_update_count = buffer.non_text_state_update_count();
3104
3105            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3106            let buffer_non_text_state_updated =
3107                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3108            if buffer_edited || buffer_non_text_state_updated {
3109                *buffer_state.last_version.borrow_mut() = version;
3110                buffer_state
3111                    .last_non_text_state_update_count
3112                    .set(non_text_state_update_count);
3113                excerpts_to_edit.extend(
3114                    buffer_state
3115                        .excerpts
3116                        .iter()
3117                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3118                );
3119            }
3120
3121            edited |= buffer_edited;
3122            non_text_state_updated |= buffer_non_text_state_updated;
3123            *is_dirty |= buffer.is_dirty();
3124            *has_deleted_file |= buffer
3125                .file()
3126                .is_some_and(|file| file.disk_state().is_deleted());
3127            *has_conflict |= buffer.has_conflict();
3128        }
3129        if edited {
3130            *edit_count += 1;
3131        }
3132        if non_text_state_updated {
3133            *non_text_state_update_count += 1;
3134        }
3135
3136        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3137
3138        let mut edits = Vec::new();
3139        let mut new_excerpts = SumTree::default();
3140        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3141
3142        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3143            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3144            let old_excerpt = cursor.item().unwrap();
3145            let buffer = buffer.read(cx);
3146            let buffer_id = buffer.remote_id();
3147            let mut new_excerpt;
3148            if buffer_edited {
3149                edits.extend(
3150                    buffer
3151                        .edits_since_in_range::<usize>(
3152                            old_excerpt.buffer.version(),
3153                            old_excerpt.range.context.clone(),
3154                        )
3155                        .map(|edit| {
3156                            let excerpt_old_start = cursor.start().1;
3157                            let excerpt_new_start =
3158                                ExcerptDimension(new_excerpts.summary().text.len);
3159                            let old_start = excerpt_old_start + edit.old.start;
3160                            let old_end = excerpt_old_start + edit.old.end;
3161                            let new_start = excerpt_new_start + edit.new.start;
3162                            let new_end = excerpt_new_start + edit.new.end;
3163                            Edit {
3164                                old: old_start..old_end,
3165                                new: new_start..new_end,
3166                            }
3167                        }),
3168                );
3169
3170                new_excerpt = Excerpt::new(
3171                    old_excerpt.id,
3172                    locator.clone(),
3173                    buffer_id,
3174                    Arc::new(buffer.snapshot()),
3175                    old_excerpt.range.clone(),
3176                    old_excerpt.has_trailing_newline,
3177                );
3178            } else {
3179                new_excerpt = old_excerpt.clone();
3180                new_excerpt.buffer = Arc::new(buffer.snapshot());
3181            }
3182
3183            new_excerpts.push(new_excerpt, ());
3184            cursor.next();
3185        }
3186        new_excerpts.append(cursor.suffix(), ());
3187
3188        drop(cursor);
3189        *excerpts = new_excerpts;
3190
3191        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3192    }
3193
3194    fn sync_diff_transforms(
3195        snapshot: &mut MultiBufferSnapshot,
3196        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3197        change_kind: DiffChangeKind,
3198    ) -> Vec<Edit<MultiBufferOffset>> {
3199        if excerpt_edits.is_empty() {
3200            return vec![];
3201        }
3202
3203        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3204        let mut old_diff_transforms = snapshot
3205            .diff_transforms
3206            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3207        let mut new_diff_transforms = SumTree::default();
3208        let mut old_expanded_hunks = HashSet::default();
3209        let mut output_edits = Vec::new();
3210        let mut output_delta = 0_isize;
3211        let mut at_transform_boundary = true;
3212        let mut end_of_current_insert = None;
3213
3214        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3215        while let Some(edit) = excerpt_edits.next() {
3216            excerpts.seek_forward(&edit.new.start, Bias::Right);
3217            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3218                excerpts.prev();
3219            }
3220
3221            // Keep any transforms that are before the edit.
3222            if at_transform_boundary {
3223                at_transform_boundary = false;
3224                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3225                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3226                if let Some(transform) = old_diff_transforms.item()
3227                    && old_diff_transforms.end().0 == edit.old.start
3228                    && old_diff_transforms.start().0 < edit.old.start
3229                {
3230                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3231                    old_diff_transforms.next();
3232                }
3233            }
3234
3235            // Compute the start of the edit in output coordinates.
3236            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3237            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3238            let edit_new_start =
3239                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3240
3241            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3242                &edit,
3243                &mut excerpts,
3244                &mut old_diff_transforms,
3245                &mut new_diff_transforms,
3246                &mut end_of_current_insert,
3247                &mut old_expanded_hunks,
3248                snapshot,
3249                change_kind,
3250            );
3251
3252            // Compute the end of the edit in output coordinates.
3253            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3254            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3255            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3256            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3257            let output_edit = Edit {
3258                old: edit_old_start..edit_old_end,
3259                new: edit_new_start..edit_new_end,
3260            };
3261
3262            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3263            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3264            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3265                output_edits.push(output_edit);
3266            }
3267
3268            // If this is the last edit that intersects the current diff transform,
3269            // then recreate the content up to the end of this transform, to prepare
3270            // for reusing additional slices of the old transforms.
3271            if excerpt_edits
3272                .peek()
3273                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3274            {
3275                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3276                    && match old_diff_transforms.item() {
3277                        Some(DiffTransform::BufferContent {
3278                            inserted_hunk_info: Some(hunk),
3279                            ..
3280                        }) => excerpts.item().is_some_and(|excerpt| {
3281                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3282                                && diff.is_inverted
3283                            {
3284                                return true;
3285                            }
3286                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3287                        }),
3288                        _ => true,
3289                    };
3290
3291                let mut excerpt_offset = edit.new.end;
3292                if !keep_next_old_transform {
3293                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3294                    old_diff_transforms.next();
3295                }
3296
3297                old_expanded_hunks.clear();
3298                Self::push_buffer_content_transform(
3299                    snapshot,
3300                    &mut new_diff_transforms,
3301                    excerpt_offset,
3302                    end_of_current_insert,
3303                );
3304                at_transform_boundary = true;
3305            }
3306        }
3307
3308        // Keep any transforms that are after the last edit.
3309        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3310
3311        // Ensure there's always at least one buffer content transform.
3312        if new_diff_transforms.is_empty() {
3313            new_diff_transforms.push(
3314                DiffTransform::BufferContent {
3315                    summary: Default::default(),
3316                    inserted_hunk_info: None,
3317                },
3318                (),
3319            );
3320        }
3321
3322        drop(old_diff_transforms);
3323        drop(excerpts);
3324        snapshot.diff_transforms = new_diff_transforms;
3325        snapshot.edit_count += 1;
3326
3327        #[cfg(any(test, feature = "test-support"))]
3328        snapshot.check_invariants();
3329        output_edits
3330    }
3331
3332    fn recompute_diff_transforms_for_edit(
3333        edit: &Edit<ExcerptOffset>,
3334        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3335        old_diff_transforms: &mut Cursor<
3336            DiffTransform,
3337            Dimensions<ExcerptOffset, MultiBufferOffset>,
3338        >,
3339        new_diff_transforms: &mut SumTree<DiffTransform>,
3340        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3341        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3342        snapshot: &MultiBufferSnapshot,
3343        change_kind: DiffChangeKind,
3344    ) -> bool {
3345        log::trace!(
3346            "recomputing diff transform for edit {:?} => {:?}",
3347            edit.old.start..edit.old.end,
3348            edit.new.start..edit.new.end
3349        );
3350
3351        // Record which hunks were previously expanded.
3352        while let Some(item) = old_diff_transforms.item() {
3353            if let Some(hunk_info) = item.hunk_info() {
3354                log::trace!(
3355                    "previously expanded hunk at {:?}",
3356                    old_diff_transforms.start()
3357                );
3358                old_expanded_hunks.insert(hunk_info);
3359            }
3360            if old_diff_transforms.end().0 > edit.old.end {
3361                break;
3362            }
3363            old_diff_transforms.next();
3364        }
3365
3366        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3367        // For inverted diffs, hunks are always shown, so we can't skip this.
3368        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3369        if old_expanded_hunks.is_empty()
3370            && change_kind == DiffChangeKind::BufferEdited
3371            && !all_diff_hunks_expanded
3372            && !snapshot.has_inverted_diff
3373        {
3374            return false;
3375        }
3376
3377        // Visit each excerpt that intersects the edit.
3378        let mut did_expand_hunks = false;
3379        while let Some(excerpt) = excerpts.item() {
3380            // Recompute the expanded hunks in the portion of the excerpt that
3381            // intersects the edit.
3382            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3383                let buffer = &excerpt.buffer;
3384                let excerpt_start = *excerpts.start();
3385                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3386                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3387                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3388                let edit_buffer_start =
3389                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3390                let edit_buffer_end =
3391                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3392                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3393
3394                if diff.is_inverted {
3395                    for hunk in diff.hunks_intersecting_base_text_range(
3396                        edit_buffer_start..edit_buffer_end,
3397                        diff.original_buffer_snapshot(),
3398                    ) {
3399                        did_expand_hunks = true;
3400                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3401                        if hunk_buffer_range.start < excerpt_buffer_start {
3402                            log::trace!("skipping hunk that starts before excerpt");
3403                            continue;
3404                        }
3405                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3406                        let hunk_excerpt_start = excerpt_start
3407                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3408                        let hunk_excerpt_end = excerpt_end
3409                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3410                        Self::push_buffer_content_transform(
3411                            snapshot,
3412                            new_diff_transforms,
3413                            hunk_excerpt_start,
3414                            *end_of_current_insert,
3415                        );
3416                        if !hunk_buffer_range.is_empty() {
3417                            let hunk_info = DiffTransformHunkInfo {
3418                                excerpt_id: excerpt.id,
3419                                hunk_start_anchor: hunk.buffer_range.start,
3420                                hunk_secondary_status: hunk.secondary_status,
3421                                is_logically_deleted: true,
3422                            };
3423                            *end_of_current_insert =
3424                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3425                        }
3426                    }
3427                } else {
3428                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3429                        ..buffer.anchor_after(edit_buffer_end);
3430                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3431                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3432                            continue;
3433                        }
3434
3435                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3436                        if hunk_buffer_range.start < excerpt_buffer_start {
3437                            log::trace!("skipping hunk that starts before excerpt");
3438                            continue;
3439                        }
3440
3441                        let hunk_info = DiffTransformHunkInfo {
3442                            excerpt_id: excerpt.id,
3443                            hunk_start_anchor: hunk.buffer_range.start,
3444                            hunk_secondary_status: hunk.secondary_status,
3445                            is_logically_deleted: false,
3446                        };
3447
3448                        let hunk_excerpt_start = excerpt_start
3449                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3450                        let hunk_excerpt_end = excerpt_end
3451                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3452
3453                        Self::push_buffer_content_transform(
3454                            snapshot,
3455                            new_diff_transforms,
3456                            hunk_excerpt_start,
3457                            *end_of_current_insert,
3458                        );
3459
3460                        // For every existing hunk, determine if it was previously expanded
3461                        // and if it should currently be expanded.
3462                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3463                        let should_expand_hunk = match &change_kind {
3464                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3465                                was_previously_expanded || all_diff_hunks_expanded
3466                            }
3467                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3468                                let intersects = hunk_buffer_range.is_empty()
3469                                    || hunk_buffer_range.end > edit_buffer_start;
3470                                if *expand {
3471                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3472                                } else {
3473                                    !intersects
3474                                        && (was_previously_expanded || all_diff_hunks_expanded)
3475                                }
3476                            }
3477                            _ => was_previously_expanded || all_diff_hunks_expanded,
3478                        };
3479
3480                        if should_expand_hunk {
3481                            did_expand_hunks = true;
3482                            log::trace!(
3483                                "expanding hunk {:?}, excerpt:{:?}",
3484                                hunk_excerpt_start..hunk_excerpt_end,
3485                                excerpt.id
3486                            );
3487
3488                            if !hunk.diff_base_byte_range.is_empty()
3489                                && hunk_buffer_range.start >= edit_buffer_start
3490                                && hunk_buffer_range.start <= excerpt_buffer_end
3491                                && snapshot.show_deleted_hunks
3492                            {
3493                                let base_text = diff.base_text();
3494                                let mut text_cursor =
3495                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3496                                let mut base_text_summary = text_cursor
3497                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3498
3499                                let mut has_trailing_newline = false;
3500                                if base_text_summary.last_line_chars > 0 {
3501                                    base_text_summary += TextSummary::newline();
3502                                    has_trailing_newline = true;
3503                                }
3504
3505                                new_diff_transforms.push(
3506                                    DiffTransform::DeletedHunk {
3507                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3508                                        summary: base_text_summary,
3509                                        buffer_id: excerpt.buffer_id,
3510                                        hunk_info,
3511                                        has_trailing_newline,
3512                                    },
3513                                    (),
3514                                );
3515                            }
3516
3517                            if !hunk_buffer_range.is_empty() {
3518                                *end_of_current_insert =
3519                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3520                            }
3521                        }
3522                    }
3523                }
3524            }
3525
3526            if excerpts.end() <= edit.new.end {
3527                excerpts.next();
3528            } else {
3529                break;
3530            }
3531        }
3532
3533        did_expand_hunks || !old_expanded_hunks.is_empty()
3534    }
3535
3536    fn append_diff_transforms(
3537        new_transforms: &mut SumTree<DiffTransform>,
3538        subtree: SumTree<DiffTransform>,
3539    ) {
3540        if let Some(DiffTransform::BufferContent {
3541            inserted_hunk_info,
3542            summary,
3543        }) = subtree.first()
3544            && Self::extend_last_buffer_content_transform(
3545                new_transforms,
3546                *inserted_hunk_info,
3547                *summary,
3548            )
3549        {
3550            let mut cursor = subtree.cursor::<()>(());
3551            cursor.next();
3552            cursor.next();
3553            new_transforms.append(cursor.suffix(), ());
3554            return;
3555        }
3556        new_transforms.append(subtree, ());
3557    }
3558
3559    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3560        if let DiffTransform::BufferContent {
3561            inserted_hunk_info: inserted_hunk_anchor,
3562            summary,
3563        } = transform
3564            && Self::extend_last_buffer_content_transform(
3565                new_transforms,
3566                inserted_hunk_anchor,
3567                summary,
3568            )
3569        {
3570            return;
3571        }
3572        new_transforms.push(transform, ());
3573    }
3574
3575    fn push_buffer_content_transform(
3576        old_snapshot: &MultiBufferSnapshot,
3577        new_transforms: &mut SumTree<DiffTransform>,
3578        end_offset: ExcerptOffset,
3579        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3580    ) {
3581        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3582            (end_offset.min(insertion_end_offset), Some(hunk_info))
3583        });
3584        let unchanged_region = [(end_offset, None)];
3585
3586        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3587        {
3588            let start_offset = new_transforms.summary().excerpt_len();
3589            if end_offset <= start_offset {
3590                continue;
3591            }
3592            let summary_to_add = old_snapshot
3593                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3594
3595            if !Self::extend_last_buffer_content_transform(
3596                new_transforms,
3597                inserted_hunk_info,
3598                summary_to_add,
3599            ) {
3600                new_transforms.push(
3601                    DiffTransform::BufferContent {
3602                        summary: summary_to_add,
3603                        inserted_hunk_info,
3604                    },
3605                    (),
3606                )
3607            }
3608        }
3609    }
3610
3611    fn extend_last_buffer_content_transform(
3612        new_transforms: &mut SumTree<DiffTransform>,
3613        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3614        summary_to_add: MBTextSummary,
3615    ) -> bool {
3616        let mut did_extend = false;
3617        new_transforms.update_last(
3618            |last_transform| {
3619                if let DiffTransform::BufferContent {
3620                    summary,
3621                    inserted_hunk_info: inserted_hunk_anchor,
3622                } = last_transform
3623                    && *inserted_hunk_anchor == new_inserted_hunk_info
3624                {
3625                    *summary += summary_to_add;
3626                    did_extend = true;
3627                }
3628            },
3629            (),
3630        );
3631        did_extend
3632    }
3633}
3634
3635fn build_excerpt_ranges(
3636    ranges: impl IntoIterator<Item = Range<Point>>,
3637    context_line_count: u32,
3638    buffer_snapshot: &BufferSnapshot,
3639) -> Vec<ExcerptRange<Point>> {
3640    ranges
3641        .into_iter()
3642        .map(|range| {
3643            let start_row = range.start.row.saturating_sub(context_line_count);
3644            let start = Point::new(start_row, 0);
3645            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3646            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3647            ExcerptRange {
3648                context: start..end,
3649                primary: range,
3650            }
3651        })
3652        .collect()
3653}
3654
3655#[cfg(any(test, feature = "test-support"))]
3656impl MultiBuffer {
3657    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3658        let buffer = cx.new(|cx| Buffer::local(text, cx));
3659        cx.new(|cx| Self::singleton(buffer, cx))
3660    }
3661
3662    pub fn build_multi<const COUNT: usize>(
3663        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3664        cx: &mut gpui::App,
3665    ) -> Entity<Self> {
3666        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3667        for (text, ranges) in excerpts {
3668            let buffer = cx.new(|cx| Buffer::local(text, cx));
3669            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3670            multi.update(cx, |multi, cx| {
3671                multi.push_excerpts(buffer, excerpt_ranges, cx)
3672            });
3673        }
3674
3675        multi
3676    }
3677
3678    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3679        cx.new(|cx| Self::singleton(buffer, cx))
3680    }
3681
3682    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3683        cx.new(|cx| {
3684            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3685            let mutation_count = rng.random_range(1..=5);
3686            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3687            multibuffer
3688        })
3689    }
3690
3691    pub fn randomly_edit(
3692        &mut self,
3693        rng: &mut impl rand::Rng,
3694        edit_count: usize,
3695        cx: &mut Context<Self>,
3696    ) {
3697        use util::RandomCharIter;
3698
3699        let snapshot = self.read(cx);
3700        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3701        let mut last_end = None;
3702        for _ in 0..edit_count {
3703            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3704                break;
3705            }
3706
3707            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3708            let end =
3709                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3710            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3711            last_end = Some(end);
3712
3713            let mut range = start..end;
3714            if rng.random_bool(0.2) {
3715                mem::swap(&mut range.start, &mut range.end);
3716            }
3717
3718            let new_text_len = rng.random_range(0..10);
3719            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3720
3721            edits.push((range, new_text.into()));
3722        }
3723        log::info!("mutating multi-buffer with {:?}", edits);
3724        drop(snapshot);
3725
3726        self.edit(edits, None, cx);
3727    }
3728
3729    pub fn randomly_edit_excerpts(
3730        &mut self,
3731        rng: &mut impl rand::Rng,
3732        mutation_count: usize,
3733        cx: &mut Context<Self>,
3734    ) {
3735        use rand::prelude::*;
3736        use std::env;
3737        use util::RandomCharIter;
3738
3739        let max_excerpts = env::var("MAX_EXCERPTS")
3740            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3741            .unwrap_or(5);
3742
3743        let mut buffers = Vec::new();
3744        for _ in 0..mutation_count {
3745            if rng.random_bool(0.05) {
3746                log::info!("Clearing multi-buffer");
3747                self.clear(cx);
3748                continue;
3749            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3750                let ids = self.excerpt_ids();
3751                let mut excerpts = HashSet::default();
3752                for _ in 0..rng.random_range(0..ids.len()) {
3753                    excerpts.extend(ids.choose(rng).copied());
3754                }
3755
3756                let line_count = rng.random_range(0..5);
3757
3758                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3759
3760                self.expand_excerpts(
3761                    excerpts.iter().cloned(),
3762                    line_count,
3763                    ExpandExcerptDirection::UpAndDown,
3764                    cx,
3765                );
3766                continue;
3767            }
3768
3769            let excerpt_ids = self.excerpt_ids();
3770            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3771                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3772                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3773                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3774                    let buffer = buffers.last().unwrap().read(cx);
3775                    log::info!(
3776                        "Creating new buffer {} with text: {:?}",
3777                        buffer.remote_id(),
3778                        buffer.text()
3779                    );
3780                    buffers.last().unwrap().clone()
3781                } else {
3782                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3783                };
3784
3785                let buffer = buffer_handle.read(cx);
3786                let buffer_text = buffer.text();
3787                let ranges = (0..rng.random_range(0..5))
3788                    .map(|_| {
3789                        let end_ix =
3790                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3791                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3792                        ExcerptRange::new(start_ix..end_ix)
3793                    })
3794                    .collect::<Vec<_>>();
3795                log::info!(
3796                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3797                    buffer_handle.read(cx).remote_id(),
3798                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3799                    ranges
3800                        .iter()
3801                        .map(|r| &buffer_text[r.context.clone()])
3802                        .collect::<Vec<_>>()
3803                );
3804
3805                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3806                log::info!("Inserted with ids: {:?}", excerpt_id);
3807            } else {
3808                let remove_count = rng.random_range(1..=excerpt_ids.len());
3809                let mut excerpts_to_remove = excerpt_ids
3810                    .choose_multiple(rng, remove_count)
3811                    .cloned()
3812                    .collect::<Vec<_>>();
3813                let snapshot = self.snapshot.borrow();
3814                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3815                drop(snapshot);
3816                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3817                self.remove_excerpts(excerpts_to_remove, cx);
3818            }
3819        }
3820    }
3821
3822    pub fn randomly_mutate(
3823        &mut self,
3824        rng: &mut impl rand::Rng,
3825        mutation_count: usize,
3826        cx: &mut Context<Self>,
3827    ) {
3828        use rand::prelude::*;
3829
3830        if rng.random_bool(0.7) || self.singleton {
3831            let buffer = self
3832                .buffers
3833                .values()
3834                .choose(rng)
3835                .map(|state| state.buffer.clone());
3836
3837            if let Some(buffer) = buffer {
3838                buffer.update(cx, |buffer, cx| {
3839                    if rng.random() {
3840                        buffer.randomly_edit(rng, mutation_count, cx);
3841                    } else {
3842                        buffer.randomly_undo_redo(rng, cx);
3843                    }
3844                });
3845            } else {
3846                self.randomly_edit(rng, mutation_count, cx);
3847            }
3848        } else {
3849            self.randomly_edit_excerpts(rng, mutation_count, cx);
3850        }
3851
3852        self.check_invariants(cx);
3853    }
3854
3855    fn check_invariants(&self, cx: &App) {
3856        self.read(cx).check_invariants();
3857    }
3858}
3859
3860impl EventEmitter<Event> for MultiBuffer {}
3861
3862impl MultiBufferSnapshot {
3863    pub fn text(&self) -> String {
3864        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3865            .map(|chunk| chunk.text)
3866            .collect()
3867    }
3868
3869    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3870        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3871            .flat_map(|c| c.chars().rev())
3872    }
3873
3874    fn reversed_chunks_in_range(
3875        &self,
3876        range: Range<MultiBufferOffset>,
3877    ) -> ReversedMultiBufferChunks<'_> {
3878        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3879        cursor.seek(&range.end);
3880        let current_chunks = cursor.region().as_ref().map(|region| {
3881            let start_overshoot = range.start.saturating_sub(region.range.start);
3882            let end_overshoot = range.end - region.range.start;
3883            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3884            let start = region.buffer_range.start + start_overshoot;
3885            region.buffer.reversed_chunks_in_range(start..end)
3886        });
3887        ReversedMultiBufferChunks {
3888            cursor,
3889            current_chunks,
3890            start: range.start,
3891            offset: range.end,
3892        }
3893    }
3894
3895    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3896        let offset = position.to_offset(self);
3897        self.text_for_range(offset..self.len())
3898            .flat_map(|chunk| chunk.chars())
3899    }
3900
3901    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3902        self.chunks(range, false).map(|chunk| chunk.text)
3903    }
3904
3905    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3906        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3907            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3908    }
3909
3910    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3911    where
3912        T: ToOffset,
3913    {
3914        let position = position.to_offset(self);
3915        position == self.clip_offset(position, Bias::Left)
3916            && self
3917                .bytes_in_range(position..self.len())
3918                .flatten()
3919                .copied()
3920                .take(needle.len())
3921                .eq(needle.bytes())
3922    }
3923
3924    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3925        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3926    }
3927
3928    pub fn diff_hunks_in_range<T: ToPoint>(
3929        &self,
3930        range: Range<T>,
3931    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3932        let query_range = range.start.to_point(self)..range.end.to_point(self);
3933        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3934            let diff = self.diffs.get(&buffer.remote_id())?;
3935            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3936                if diff.is_inverted {
3937                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3938                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3939                    Box::new(
3940                        diff.hunks_intersecting_base_text_range(
3941                            buffer_start..buffer_end,
3942                            diff.original_buffer_snapshot(),
3943                        )
3944                        .map(move |hunk| (hunk, buffer, true)),
3945                    )
3946                } else {
3947                    let buffer_start = buffer.anchor_before(buffer_range.start);
3948                    let buffer_end = buffer.anchor_after(buffer_range.end);
3949                    Box::new(
3950                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3951                            .map(move |hunk| (hunk, buffer, false)),
3952                    )
3953                };
3954            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3955                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3956                    return None;
3957                }
3958                let range = if is_inverted {
3959                    hunk.diff_base_byte_range.to_point(&buffer)
3960                } else {
3961                    hunk.range.clone()
3962                };
3963                Some((range, (hunk, is_inverted)))
3964            }))
3965        })
3966        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3967            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3968            {
3969                return None;
3970            }
3971            let end_row = if range.end.column == 0 {
3972                range.end.row
3973            } else {
3974                range.end.row + 1
3975            };
3976
3977            let word_diffs =
3978                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3979                    .then(|| {
3980                        let mut word_diffs = Vec::new();
3981
3982                        if self.show_deleted_hunks || is_inverted {
3983                            let hunk_start_offset = if is_inverted {
3984                                Anchor::in_buffer(
3985                                    excerpt.id,
3986                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3987                                )
3988                                .to_offset(self)
3989                            } else {
3990                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3991                                    .to_offset(self)
3992                            };
3993
3994                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3995                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3996                            }));
3997                        }
3998
3999                        if !is_inverted {
4000                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4001                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4002                            }));
4003                        }
4004                        word_diffs
4005                    })
4006                    .unwrap_or_default();
4007
4008            let buffer_range = if is_inverted {
4009                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4010                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4011            } else {
4012                hunk.buffer_range.clone()
4013            };
4014            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4015                DiffHunkStatusKind::Deleted
4016            } else if hunk.diff_base_byte_range.is_empty() {
4017                DiffHunkStatusKind::Added
4018            } else {
4019                DiffHunkStatusKind::Modified
4020            };
4021            Some(MultiBufferDiffHunk {
4022                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4023                buffer_id: excerpt.buffer_id,
4024                excerpt_id: excerpt.id,
4025                buffer_range,
4026                word_diffs,
4027                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4028                    ..BufferOffset(hunk.diff_base_byte_range.end),
4029                status: DiffHunkStatus {
4030                    kind: status_kind,
4031                    secondary: hunk.secondary_status,
4032                },
4033            })
4034        })
4035    }
4036
4037    fn excerpts_for_range<T: ToOffset>(
4038        &self,
4039        range: Range<T>,
4040    ) -> impl Iterator<Item = &Excerpt> + '_ {
4041        let range = range.start.to_offset(self)..range.end.to_offset(self);
4042        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4043        cursor.seek(&range.start);
4044        std::iter::from_fn(move || {
4045            let region = cursor.region()?;
4046            if region.range.start > range.end
4047                || region.range.start == range.end && region.range.start > range.start
4048            {
4049                return None;
4050            }
4051            let excerpt = region.excerpt;
4052            cursor.next_excerpt_forwards();
4053            Some(excerpt)
4054        })
4055    }
4056
4057    pub fn excerpt_ids_for_range<T: ToOffset>(
4058        &self,
4059        range: Range<T>,
4060    ) -> impl Iterator<Item = ExcerptId> + '_ {
4061        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4062    }
4063
4064    pub fn buffer_ids_for_range<T: ToOffset>(
4065        &self,
4066        range: Range<T>,
4067    ) -> impl Iterator<Item = BufferId> + '_ {
4068        self.excerpts_for_range(range)
4069            .map(|excerpt| excerpt.buffer_id)
4070    }
4071
4072    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4073    ///
4074    /// The passed in anchors must be ordered.
4075    pub fn text_anchors_to_visible_anchors(
4076        &self,
4077        anchors: impl IntoIterator<Item = text::Anchor>,
4078    ) -> Vec<Option<Anchor>> {
4079        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4080        let mut anchors = anchors.into_iter().peekable();
4081        let mut result = Vec::new();
4082        'anchors: while let Some(anchor) = anchors.peek() {
4083            let Some(buffer_id) = anchor.buffer_id else {
4084                anchors.next();
4085                result.push(None);
4086                continue 'anchors;
4087            };
4088            let mut same_buffer_anchors =
4089                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4090
4091            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4092                let Some(mut next) = same_buffer_anchors.next() else {
4093                    continue 'anchors;
4094                };
4095                'excerpts: for locator in locators.iter() {
4096                    if cursor.seek_forward(&Some(locator), Bias::Left)
4097                        && let Some(excerpt) = cursor.item()
4098                    {
4099                        loop {
4100                            // anchor is before the first excerpt
4101                            if excerpt
4102                                .range
4103                                .context
4104                                .start
4105                                .cmp(&next, &excerpt.buffer)
4106                                .is_gt()
4107                            {
4108                                // so we skip it and try the next anchor
4109                                result.push(None);
4110                                match same_buffer_anchors.next() {
4111                                    Some(anchor) => next = anchor,
4112                                    None => continue 'anchors,
4113                                }
4114                            // anchor is within the excerpt
4115                            } else if excerpt
4116                                .range
4117                                .context
4118                                .end
4119                                .cmp(&next, &excerpt.buffer)
4120                                .is_ge()
4121                            {
4122                                // record it and all following anchors that are within
4123                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4124                                result.extend(
4125                                    same_buffer_anchors
4126                                        .peeking_take_while(|a| {
4127                                            excerpt
4128                                                .range
4129                                                .context
4130                                                .end
4131                                                .cmp(a, &excerpt.buffer)
4132                                                .is_ge()
4133                                        })
4134                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4135                                );
4136                                match same_buffer_anchors.next() {
4137                                    Some(anchor) => next = anchor,
4138                                    None => continue 'anchors,
4139                                }
4140                            // anchor is after the excerpt, try the next one
4141                            } else {
4142                                continue 'excerpts;
4143                            }
4144                        }
4145                    }
4146                }
4147                // account for `next`
4148                result.push(None);
4149            }
4150            result.extend(same_buffer_anchors.map(|_| None));
4151        }
4152
4153        result
4154    }
4155
4156    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4157        &self,
4158        ranges: impl Iterator<Item = Range<T>>,
4159    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4160        ranges.flat_map(|range| {
4161            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4162                .into_iter()
4163        })
4164    }
4165
4166    pub fn range_to_buffer_ranges<R, T>(
4167        &self,
4168        range: R,
4169    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4170    where
4171        R: RangeBounds<T>,
4172        T: ToOffset,
4173    {
4174        self.range_to_buffer_ranges_with_context(range)
4175            .into_iter()
4176            .map(|(buffer, range, id, _context)| (buffer, range, id))
4177            .collect()
4178    }
4179
4180    pub fn range_to_buffer_ranges_with_context<R, T>(
4181        &self,
4182        range: R,
4183    ) -> Vec<(
4184        &BufferSnapshot,
4185        Range<BufferOffset>,
4186        ExcerptId,
4187        Range<text::Anchor>,
4188    )>
4189    where
4190        R: RangeBounds<T>,
4191        T: ToOffset,
4192    {
4193        let start = match range.start_bound() {
4194            Bound::Included(start) => start.to_offset(self),
4195            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4196            Bound::Unbounded => MultiBufferOffset::ZERO,
4197        };
4198        let end_bound = match range.end_bound() {
4199            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4200            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4201            Bound::Unbounded => Bound::Unbounded,
4202        };
4203        let bounds = (Bound::Included(start), end_bound);
4204
4205        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4206        cursor.seek(&start);
4207
4208        let mut result: Vec<(
4209            &BufferSnapshot,
4210            Range<BufferOffset>,
4211            ExcerptId,
4212            Range<text::Anchor>,
4213        )> = Vec::new();
4214        while let Some(region) = cursor.region() {
4215            let dominated_by_end_bound = match end_bound {
4216                Bound::Included(end) => region.range.start > end,
4217                Bound::Excluded(end) => region.range.start >= end,
4218                Bound::Unbounded => false,
4219            };
4220            if dominated_by_end_bound {
4221                break;
4222            }
4223            if region.is_main_buffer {
4224                let start_overshoot = start.saturating_sub(region.range.start);
4225                let end_offset = match end_bound {
4226                    Bound::Included(end) | Bound::Excluded(end) => end,
4227                    Bound::Unbounded => region.range.end,
4228                };
4229                let end_overshoot = end_offset.saturating_sub(region.range.start);
4230                let start = region
4231                    .buffer_range
4232                    .end
4233                    .min(region.buffer_range.start + start_overshoot);
4234                let end = region
4235                    .buffer_range
4236                    .end
4237                    .min(region.buffer_range.start + end_overshoot);
4238                let context = region.excerpt.range.context.clone();
4239                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4240                    *excerpt_id == region.excerpt.id && prev_range.end == start
4241                }) {
4242                    prev.1.end = end;
4243                } else {
4244                    result.push((region.buffer, start..end, region.excerpt.id, context));
4245                }
4246            }
4247            cursor.next();
4248        }
4249
4250        if let Some(excerpt) = cursor.excerpt() {
4251            let dominated_by_prev_excerpt =
4252                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4253            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4254                let excerpt_position = self.len();
4255                if bounds.contains(&excerpt_position) {
4256                    let buffer_offset =
4257                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4258                    let context = excerpt.range.context.clone();
4259                    result.push((
4260                        &excerpt.buffer,
4261                        buffer_offset..buffer_offset,
4262                        excerpt.id,
4263                        context,
4264                    ));
4265                }
4266            }
4267        }
4268
4269        result
4270    }
4271
4272    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4273        &self,
4274        range: Range<T>,
4275    ) -> impl Iterator<
4276        Item = (
4277            &BufferSnapshot,
4278            Range<BufferOffset>,
4279            ExcerptId,
4280            Option<Anchor>,
4281        ),
4282    > + '_ {
4283        let start = range.start.to_offset(self);
4284        let end = range.end.to_offset(self);
4285
4286        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4287        cursor.seek(&start);
4288
4289        std::iter::from_fn(move || {
4290            let region = cursor.region()?;
4291            if region.range.start > end {
4292                return None;
4293            }
4294            let start_overshoot = start.saturating_sub(region.range.start);
4295            let end_overshoot = end.saturating_sub(region.range.start);
4296            let start = region
4297                .buffer_range
4298                .end
4299                .min(region.buffer_range.start + start_overshoot);
4300            let end = region
4301                .buffer_range
4302                .end
4303                .min(region.buffer_range.start + end_overshoot);
4304
4305            let region_excerpt_id = region.excerpt.id;
4306            let deleted_hunk_anchor = if region.is_main_buffer {
4307                None
4308            } else {
4309                Some(self.anchor_before(region.range.start))
4310            };
4311            let result = (
4312                region.buffer,
4313                start..end,
4314                region_excerpt_id,
4315                deleted_hunk_anchor,
4316            );
4317            cursor.next();
4318            Some(result)
4319        })
4320    }
4321
4322    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4323    /// coordinates.
4324    ///
4325    /// The given callback will be called for every excerpt intersecting the given range. It will
4326    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4327    /// The callback should return an iterator of metadata items from that buffer, each paired
4328    /// with a buffer range.
4329    ///
4330    /// The returned iterator yields each of these metadata items, paired with its range in
4331    /// multi-buffer coordinates.
4332    fn lift_buffer_metadata<'a, MBD, M, I>(
4333        &'a self,
4334        query_range: Range<MBD>,
4335        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4336    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4337    where
4338        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4339        MBD: MultiBufferDimension
4340            + Ord
4341            + Sub<Output = MBD::TextDimension>
4342            + ops::Add<MBD::TextDimension, Output = MBD>
4343            + ops::AddAssign<MBD::TextDimension>,
4344        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4345            + ops::Add<Output = MBD::TextDimension>
4346            + AddAssign<MBD::TextDimension>
4347            + Ord,
4348    {
4349        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4350        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4351
4352        // Find the excerpt and buffer offset where the given range ends.
4353        cursor.seek(&query_range.end);
4354        let mut range_end = None;
4355        while let Some(region) = cursor.region() {
4356            if region.is_main_buffer {
4357                let mut buffer_end = region.buffer_range.start;
4358                let overshoot = if query_range.end > region.range.start {
4359                    query_range.end - region.range.start
4360                } else {
4361                    <MBD::TextDimension>::default()
4362                };
4363                buffer_end = buffer_end + overshoot;
4364                range_end = Some((region.excerpt.id, buffer_end));
4365                break;
4366            }
4367            cursor.next();
4368        }
4369
4370        cursor.seek(&query_range.start);
4371
4372        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4373            && region.range.start > MBD::default()
4374        {
4375            cursor.prev()
4376        } else if let Some(region) = cursor.region()
4377            && region.is_main_buffer
4378            && region.diff_hunk_status.is_some()
4379        {
4380            cursor.prev();
4381            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4382                cursor.next();
4383            }
4384        }
4385
4386        iter::from_fn(move || {
4387            loop {
4388                let excerpt = cursor.excerpt()?;
4389
4390                // If we have already retrieved metadata for this excerpt, continue to use it.
4391                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4392                    .as_mut()
4393                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4394                {
4395                    Some(metadata)
4396                }
4397                // Otherwise, compute the intersection of the input range with the excerpt's range,
4398                // and retrieve the metadata for the resulting range.
4399                else {
4400                    let region = cursor.region()?;
4401                    let mut buffer_start;
4402                    if region.is_main_buffer {
4403                        buffer_start = region.buffer_range.start;
4404                        if query_range.start > region.range.start {
4405                            let overshoot = query_range.start - region.range.start;
4406                            buffer_start = buffer_start + overshoot;
4407                        }
4408                        buffer_start = buffer_start.min(region.buffer_range.end);
4409                    } else {
4410                        buffer_start = cursor.main_buffer_position()?;
4411                    };
4412                    let mut buffer_end = excerpt
4413                        .range
4414                        .context
4415                        .end
4416                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4417                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4418                        && excerpt.id == end_excerpt_id
4419                    {
4420                        buffer_end = buffer_end.min(end_buffer_offset);
4421                    }
4422
4423                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4424                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4425                    })
4426                };
4427
4428                // Visit each metadata item.
4429                if let Some((metadata_buffer_range, metadata)) =
4430                    metadata_iter.and_then(Iterator::next)
4431                {
4432                    // Find the multibuffer regions that contain the start and end of
4433                    // the metadata item's range.
4434                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4435                        while let Some(region) = cursor.region() {
4436                            if (region.is_main_buffer
4437                                && (region.buffer_range.end >= metadata_buffer_range.start
4438                                    || cursor.is_at_end_of_excerpt()))
4439                                || (!region.is_main_buffer
4440                                    && region.buffer_range.start == metadata_buffer_range.start)
4441                            {
4442                                break;
4443                            }
4444                            cursor.next();
4445                        }
4446                    }
4447                    let start_region = cursor.region()?.clone();
4448                    while let Some(region) = cursor.region() {
4449                        if region.is_main_buffer
4450                            && (region.buffer_range.end > metadata_buffer_range.end
4451                                || cursor.is_at_end_of_excerpt())
4452                        {
4453                            break;
4454                        }
4455                        cursor.next();
4456                    }
4457                    let end_region = cursor.region();
4458
4459                    // Convert the metadata item's range into multibuffer coordinates.
4460                    let mut start_position = start_region.range.start;
4461                    let region_buffer_start = start_region.buffer_range.start;
4462                    if start_region.is_main_buffer
4463                        && metadata_buffer_range.start > region_buffer_start
4464                    {
4465                        start_position =
4466                            start_position + (metadata_buffer_range.start - region_buffer_start);
4467                        start_position = start_position.min(start_region.range.end);
4468                    }
4469
4470                    let mut end_position = self.max_position();
4471                    if let Some(end_region) = &end_region {
4472                        end_position = end_region.range.start;
4473                        debug_assert!(end_region.is_main_buffer);
4474                        let region_buffer_start = end_region.buffer_range.start;
4475                        if metadata_buffer_range.end > region_buffer_start {
4476                            end_position =
4477                                end_position + (metadata_buffer_range.end - region_buffer_start);
4478                        }
4479                        end_position = end_position.min(end_region.range.end);
4480                    }
4481
4482                    if start_position <= query_range.end && end_position >= query_range.start {
4483                        return Some((start_position..end_position, metadata, excerpt));
4484                    }
4485                }
4486                // When there are no more metadata items for this excerpt, move to the next excerpt.
4487                else {
4488                    current_excerpt_metadata.take();
4489                    if let Some((end_excerpt_id, _)) = range_end
4490                        && excerpt.id == end_excerpt_id
4491                    {
4492                        return None;
4493                    }
4494                    cursor.next_excerpt_forwards();
4495                }
4496            }
4497        })
4498    }
4499
4500    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4501        let offset = position.to_offset(self);
4502
4503        let mut cursor = self
4504            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4505            );
4506        cursor.seek(&DimensionPair {
4507            key: offset,
4508            value: None,
4509        });
4510        cursor.seek_to_start_of_current_excerpt();
4511        let excerpt = cursor.excerpt()?;
4512
4513        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4514        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4515        let current_position = self
4516            .anchor_before(offset)
4517            .text_anchor
4518            .to_offset(&excerpt.buffer);
4519
4520        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4521            if diff.is_inverted {
4522                for hunk in diff.hunks_intersecting_base_text_range_rev(
4523                    excerpt_start..excerpt_end,
4524                    diff.original_buffer_snapshot(),
4525                ) {
4526                    if hunk.diff_base_byte_range.end >= current_position {
4527                        continue;
4528                    }
4529                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4530                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4531                    return Some(MultiBufferRow(start.row));
4532                }
4533            } else {
4534                let excerpt_end = excerpt
4535                    .buffer
4536                    .anchor_before(excerpt_end.min(current_position));
4537                for hunk in diff.hunks_intersecting_range_rev(
4538                    excerpt.range.context.start..excerpt_end,
4539                    &excerpt.buffer,
4540                ) {
4541                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4542                    if hunk_end >= current_position {
4543                        continue;
4544                    }
4545                    let start =
4546                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4547                    return Some(MultiBufferRow(start.row));
4548                }
4549            }
4550        }
4551
4552        loop {
4553            cursor.prev_excerpt();
4554            let excerpt = cursor.excerpt()?;
4555
4556            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4557                continue;
4558            };
4559            if diff.is_inverted {
4560                let Some(hunk) = diff
4561                    .hunks_intersecting_base_text_range_rev(
4562                        excerpt.range.context.to_offset(&excerpt.buffer),
4563                        diff.original_buffer_snapshot(),
4564                    )
4565                    .next()
4566                else {
4567                    continue;
4568                };
4569                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4570                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4571                return Some(MultiBufferRow(start.row));
4572            } else {
4573                let Some(hunk) = diff
4574                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4575                    .next()
4576                else {
4577                    continue;
4578                };
4579                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4580                return Some(MultiBufferRow(start.row));
4581            }
4582        }
4583    }
4584
4585    pub fn has_diff_hunks(&self) -> bool {
4586        self.diffs.values().any(|diff| !diff.is_empty())
4587    }
4588
4589    pub fn is_inside_word<T: ToOffset>(
4590        &self,
4591        position: T,
4592        scope_context: Option<CharScopeContext>,
4593    ) -> bool {
4594        let position = position.to_offset(self);
4595        let classifier = self
4596            .char_classifier_at(position)
4597            .scope_context(scope_context);
4598        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4599        let prev_char_kind = self
4600            .reversed_chars_at(position)
4601            .next()
4602            .map(|c| classifier.kind(c));
4603        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4604    }
4605
4606    pub fn surrounding_word<T: ToOffset>(
4607        &self,
4608        start: T,
4609        scope_context: Option<CharScopeContext>,
4610    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4611        let mut start = start.to_offset(self);
4612        let mut end = start;
4613        let mut next_chars = self.chars_at(start).peekable();
4614        let mut prev_chars = self.reversed_chars_at(start).peekable();
4615
4616        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4617
4618        let word_kind = cmp::max(
4619            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4620            next_chars.peek().copied().map(|c| classifier.kind(c)),
4621        );
4622
4623        for ch in prev_chars {
4624            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4625                start -= ch.len_utf8();
4626            } else {
4627                break;
4628            }
4629        }
4630
4631        for ch in next_chars {
4632            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4633                end += ch.len_utf8();
4634            } else {
4635                break;
4636            }
4637        }
4638
4639        (start..end, word_kind)
4640    }
4641
4642    pub fn char_kind_before<T: ToOffset>(
4643        &self,
4644        start: T,
4645        scope_context: Option<CharScopeContext>,
4646    ) -> Option<CharKind> {
4647        let start = start.to_offset(self);
4648        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4649        self.reversed_chars_at(start)
4650            .next()
4651            .map(|ch| classifier.kind(ch))
4652    }
4653
4654    pub fn is_singleton(&self) -> bool {
4655        self.singleton
4656    }
4657
4658    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4659        if self.singleton {
4660            self.excerpts
4661                .iter()
4662                .next()
4663                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4664        } else {
4665            None
4666        }
4667    }
4668
4669    pub fn len(&self) -> MultiBufferOffset {
4670        self.diff_transforms.summary().output.len
4671    }
4672
4673    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4674        MBD::from_summary(&self.text_summary())
4675    }
4676
4677    pub fn is_empty(&self) -> bool {
4678        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4679    }
4680
4681    pub fn widest_line_number(&self) -> u32 {
4682        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4683        self.excerpts.summary().widest_line_number + 1
4684    }
4685
4686    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4687        let range = range.start.to_offset(self)..range.end.to_offset(self);
4688        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4689        excerpts.seek(&range.start);
4690
4691        let mut chunk;
4692        let mut has_trailing_newline;
4693        let excerpt_bytes;
4694        if let Some(region) = excerpts.region() {
4695            let mut bytes = region.buffer.bytes_in_range(
4696                region.buffer_range.start + (range.start - region.range.start)
4697                    ..(region.buffer_range.start + (range.end - region.range.start))
4698                        .min(region.buffer_range.end),
4699            );
4700            chunk = bytes.next().unwrap_or(&[][..]);
4701            excerpt_bytes = Some(bytes);
4702            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4703            if chunk.is_empty() && has_trailing_newline {
4704                chunk = b"\n";
4705                has_trailing_newline = false;
4706            }
4707        } else {
4708            chunk = &[][..];
4709            excerpt_bytes = None;
4710            has_trailing_newline = false;
4711        };
4712
4713        MultiBufferBytes {
4714            range,
4715            cursor: excerpts,
4716            excerpt_bytes,
4717            has_trailing_newline,
4718            chunk,
4719        }
4720    }
4721
4722    pub fn reversed_bytes_in_range<T: ToOffset>(
4723        &self,
4724        range: Range<T>,
4725    ) -> ReversedMultiBufferBytes<'_> {
4726        let range = range.start.to_offset(self)..range.end.to_offset(self);
4727        let mut chunks = self.reversed_chunks_in_range(range.clone());
4728        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4729        ReversedMultiBufferBytes {
4730            range,
4731            chunks,
4732            chunk,
4733        }
4734    }
4735
4736    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4737        let mut cursor = self.cursor::<Point, Point>();
4738        cursor.seek(&Point::new(start_row.0, 0));
4739        let mut result = MultiBufferRows {
4740            point: Point::new(0, 0),
4741            is_empty: self.excerpts.is_empty(),
4742            is_singleton: self.is_singleton(),
4743            cursor,
4744        };
4745        result.seek(start_row);
4746        result
4747    }
4748
4749    pub fn chunks<T: ToOffset>(
4750        &self,
4751        range: Range<T>,
4752        language_aware: bool,
4753    ) -> MultiBufferChunks<'_> {
4754        let mut chunks = MultiBufferChunks {
4755            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4756                ..ExcerptDimension(MultiBufferOffset::ZERO),
4757            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4758            excerpts: self.excerpts.cursor(()),
4759            diff_transforms: self.diff_transforms.cursor(()),
4760            diffs: &self.diffs,
4761            diff_base_chunks: None,
4762            excerpt_chunks: None,
4763            buffer_chunk: None,
4764            language_aware,
4765        };
4766        let range = range.start.to_offset(self)..range.end.to_offset(self);
4767        chunks.seek(range);
4768        chunks
4769    }
4770
4771    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4772        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4773    }
4774
4775    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4776        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4777    }
4778
4779    pub fn clip_offset_utf16(
4780        &self,
4781        offset: MultiBufferOffsetUtf16,
4782        bias: Bias,
4783    ) -> MultiBufferOffsetUtf16 {
4784        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4785    }
4786
4787    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4788        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4789            buffer.clip_point_utf16(Unclipped(point), bias)
4790        })
4791    }
4792
4793    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4794        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4795    }
4796
4797    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4798        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4799    }
4800
4801    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4802        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4803    }
4804
4805    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4806        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4807    }
4808
4809    #[instrument(skip_all)]
4810    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4811        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4812    }
4813
4814    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4815        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4816    }
4817
4818    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4819        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4820    }
4821
4822    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4823        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4824    }
4825
4826    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4827        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4828    }
4829
4830    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4831        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4832    }
4833
4834    fn clip_dimension<MBD, BD>(
4835        &self,
4836        position: MBD,
4837        bias: Bias,
4838        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4839    ) -> MBD
4840    where
4841        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4842        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4843    {
4844        let mut cursor = self.cursor::<MBD, BD>();
4845        cursor.seek(&position);
4846        if let Some(region) = cursor.region() {
4847            if position >= region.range.end {
4848                return region.range.end;
4849            }
4850            let overshoot = position - region.range.start;
4851            let mut buffer_position = region.buffer_range.start;
4852            buffer_position += overshoot;
4853            let clipped_buffer_position =
4854                clip_buffer_position(region.buffer, buffer_position, bias);
4855            let mut position = region.range.start;
4856            position += clipped_buffer_position - region.buffer_range.start;
4857            position
4858        } else {
4859            self.max_position()
4860        }
4861    }
4862
4863    #[instrument(skip_all)]
4864    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4865        &self,
4866        key: MBR1,
4867        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4868    ) -> MBR2
4869    where
4870        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4871        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4872        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4873        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4874    {
4875        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4876        cursor.seek(&DimensionPair { key, value: None });
4877        if let Some(region) = cursor.region() {
4878            if key >= region.range.end.key {
4879                return region.range.end.value.unwrap();
4880            }
4881            let start_key = region.range.start.key;
4882            let start_value = region.range.start.value.unwrap();
4883            let buffer_start_key = region.buffer_range.start.key;
4884            let buffer_start_value = region.buffer_range.start.value.unwrap();
4885            let mut buffer_key = buffer_start_key;
4886            buffer_key += key - start_key;
4887            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4888            let mut result = start_value;
4889            result += buffer_value - buffer_start_value;
4890            result
4891        } else {
4892            self.max_position()
4893        }
4894    }
4895
4896    pub fn point_to_buffer_offset<T: ToOffset>(
4897        &self,
4898        point: T,
4899    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4900        let offset = point.to_offset(self);
4901        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4902        cursor.seek(&offset);
4903        let region = cursor.region()?;
4904        let overshoot = offset - region.range.start;
4905        let buffer_offset = region.buffer_range.start + overshoot;
4906        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4907            && region.has_trailing_newline
4908            && !region.is_main_buffer
4909        {
4910            let main_buffer_position = cursor.main_buffer_position()?;
4911            let buffer_snapshot = &cursor.excerpt()?.buffer;
4912            return Some((buffer_snapshot, main_buffer_position));
4913        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4914            return None;
4915        }
4916        Some((region.buffer, buffer_offset))
4917    }
4918
4919    pub fn point_to_buffer_point(
4920        &self,
4921        point: Point,
4922    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4923        let mut cursor = self.cursor::<Point, Point>();
4924        cursor.seek(&point);
4925        let region = cursor.region()?;
4926        let overshoot = point - region.range.start;
4927        let buffer_point = region.buffer_range.start + overshoot;
4928        let excerpt = cursor.excerpt()?;
4929        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4930            && region.has_trailing_newline
4931            && !region.is_main_buffer
4932        {
4933            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4934        } else if buffer_point > region.buffer.max_point() {
4935            return None;
4936        }
4937        Some((region.buffer, buffer_point, excerpt.id))
4938    }
4939
4940    pub fn suggested_indents(
4941        &self,
4942        rows: impl IntoIterator<Item = u32>,
4943        cx: &App,
4944    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4945        let mut result = BTreeMap::new();
4946        self.suggested_indents_callback(
4947            rows,
4948            |row, indent| {
4949                result.insert(row, indent);
4950                ControlFlow::Continue(())
4951            },
4952            cx,
4953        );
4954        result
4955    }
4956
4957    // move this to be a generator once those are a thing
4958    pub fn suggested_indents_callback(
4959        &self,
4960        rows: impl IntoIterator<Item = u32>,
4961        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4962        cx: &App,
4963    ) {
4964        let mut rows_for_excerpt = Vec::new();
4965        let mut cursor = self.cursor::<Point, Point>();
4966        let mut rows = rows.into_iter().peekable();
4967        let mut prev_row = u32::MAX;
4968        let mut prev_language_indent_size = IndentSize::default();
4969
4970        while let Some(row) = rows.next() {
4971            cursor.seek(&Point::new(row, 0));
4972            let Some(region) = cursor.region() else {
4973                continue;
4974            };
4975
4976            // Retrieve the language and indent size once for each disjoint region being indented.
4977            let single_indent_size = if row.saturating_sub(1) == prev_row {
4978                prev_language_indent_size
4979            } else {
4980                region
4981                    .buffer
4982                    .language_indent_size_at(Point::new(row, 0), cx)
4983            };
4984            prev_language_indent_size = single_indent_size;
4985            prev_row = row;
4986
4987            let start_buffer_row = region.buffer_range.start.row;
4988            let start_multibuffer_row = region.range.start.row;
4989            let end_multibuffer_row = region.range.end.row;
4990
4991            rows_for_excerpt.push(row);
4992            while let Some(next_row) = rows.peek().copied() {
4993                if end_multibuffer_row > next_row {
4994                    rows_for_excerpt.push(next_row);
4995                    rows.next();
4996                } else {
4997                    break;
4998                }
4999            }
5000
5001            let buffer_rows = rows_for_excerpt
5002                .drain(..)
5003                .map(|row| start_buffer_row + row - start_multibuffer_row);
5004            let buffer_indents = region
5005                .buffer
5006                .suggested_indents(buffer_rows, single_indent_size);
5007            for (row, indent) in buffer_indents {
5008                if cb(
5009                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5010                    indent,
5011                )
5012                .is_break()
5013                {
5014                    return;
5015                }
5016            }
5017        }
5018    }
5019
5020    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5021        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5022            let mut size = buffer.indent_size_for_line(range.start.row);
5023            size.len = size
5024                .len
5025                .min(range.end.column)
5026                .saturating_sub(range.start.column);
5027            size
5028        } else {
5029            IndentSize::spaces(0)
5030        }
5031    }
5032
5033    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5034        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5035            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5036        } else {
5037            LineIndent::spaces(0)
5038        }
5039    }
5040
5041    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5042        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5043
5044        if self.language_settings(cx).extend_comment_on_newline
5045            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5046        {
5047            let delimiters = language_scope.line_comment_prefixes();
5048            for delimiter in delimiters {
5049                if *self
5050                    .chars_at(Point::new(row.0, indent.len() as u32))
5051                    .take(delimiter.chars().count())
5052                    .collect::<String>()
5053                    .as_str()
5054                    == **delimiter
5055                {
5056                    indent.push_str(delimiter);
5057                    break;
5058                }
5059            }
5060        }
5061
5062        indent
5063    }
5064
5065    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5066    where
5067        T: ToOffset,
5068    {
5069        for char in self.reversed_chars_at(position) {
5070            if !char.is_whitespace() {
5071                return false;
5072            }
5073            if char == '\n' {
5074                return true;
5075            }
5076        }
5077        true
5078    }
5079
5080    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5081        while row.0 > 0 {
5082            row.0 -= 1;
5083            if !self.is_line_blank(row) {
5084                return Some(row);
5085            }
5086        }
5087        None
5088    }
5089
5090    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5091        if let Some((_, range)) = self.buffer_line_for_row(row) {
5092            range.end.column - range.start.column
5093        } else {
5094            0
5095        }
5096    }
5097
5098    pub fn buffer_line_for_row(
5099        &self,
5100        row: MultiBufferRow,
5101    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5102        let mut cursor = self.cursor::<Point, Point>();
5103        let point = Point::new(row.0, 0);
5104        cursor.seek(&point);
5105        let region = cursor.region()?;
5106        let overshoot = point.min(region.range.end) - region.range.start;
5107        let buffer_point = region.buffer_range.start + overshoot;
5108        if buffer_point.row > region.buffer_range.end.row {
5109            return None;
5110        }
5111        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5112        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5113            .min(region.buffer_range.end);
5114        Some((region.buffer, line_start..line_end))
5115    }
5116
5117    pub fn max_point(&self) -> Point {
5118        self.text_summary().lines
5119    }
5120
5121    pub fn max_row(&self) -> MultiBufferRow {
5122        MultiBufferRow(self.text_summary().lines.row)
5123    }
5124
5125    pub fn text_summary(&self) -> MBTextSummary {
5126        self.diff_transforms.summary().output
5127    }
5128
5129    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5130    where
5131        MBD: MultiBufferDimension + AddAssign,
5132        O: ToOffset,
5133    {
5134        let range = range.start.to_offset(self)..range.end.to_offset(self);
5135        let mut cursor = self
5136            .diff_transforms
5137            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5138        cursor.seek(&range.start, Bias::Right);
5139
5140        let Some(first_transform) = cursor.item() else {
5141            return MBD::from_summary(&MBTextSummary::default());
5142        };
5143
5144        let diff_transform_start = cursor.start().0;
5145        let diff_transform_end = cursor.end().0;
5146        let diff_start = range.start;
5147        let start_overshoot = diff_start - diff_transform_start;
5148        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5149
5150        let mut result = match first_transform {
5151            DiffTransform::BufferContent { .. } => {
5152                let excerpt_start = cursor.start().1 + start_overshoot;
5153                let excerpt_end = cursor.start().1 + end_overshoot;
5154                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5155            }
5156            DiffTransform::DeletedHunk {
5157                buffer_id,
5158                base_text_byte_range,
5159                has_trailing_newline,
5160                ..
5161            } => {
5162                let buffer_start = base_text_byte_range.start + start_overshoot;
5163                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5164                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5165                    panic!("{:?} is in non-existent deleted hunk", range.start)
5166                };
5167
5168                let include_trailing_newline =
5169                    *has_trailing_newline && range.end >= diff_transform_end;
5170                if include_trailing_newline {
5171                    buffer_end -= 1;
5172                }
5173
5174                let mut summary = base_text
5175                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5176
5177                if include_trailing_newline {
5178                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5179                        &TextSummary::newline(),
5180                    ))
5181                }
5182
5183                let mut result = MBD::default();
5184                result.add_text_dim(&summary);
5185                result
5186            }
5187        };
5188        if range.end < diff_transform_end {
5189            return result;
5190        }
5191
5192        cursor.next();
5193        result.add_mb_text_summary(
5194            &cursor
5195                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5196                .0,
5197        );
5198
5199        let Some(last_transform) = cursor.item() else {
5200            return result;
5201        };
5202
5203        let overshoot = range.end - cursor.start().0;
5204        let suffix = match last_transform {
5205            DiffTransform::BufferContent { .. } => {
5206                let end = cursor.start().1 + overshoot;
5207                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5208            }
5209            DiffTransform::DeletedHunk {
5210                base_text_byte_range,
5211                buffer_id,
5212                has_trailing_newline,
5213                ..
5214            } => {
5215                let buffer_end = base_text_byte_range.start + overshoot;
5216                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5217                    panic!("{:?} is in non-existent deleted hunk", range.end)
5218                };
5219
5220                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5221                    base_text_byte_range.start..buffer_end,
5222                );
5223                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5224                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5225                        &TextSummary::from("\n"),
5226                    ))
5227                }
5228
5229                let mut result = MBD::default();
5230                result.add_text_dim(&suffix);
5231                result
5232            }
5233        };
5234
5235        result += suffix;
5236        result
5237    }
5238
5239    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5240    where
5241        MBD: MultiBufferDimension + AddAssign,
5242    {
5243        let mut summary = MBD::default();
5244        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5245        cursor.seek(&range.start, Bias::Right);
5246        if let Some(excerpt) = cursor.item() {
5247            let mut end_before_newline = cursor.end();
5248            if excerpt.has_trailing_newline {
5249                end_before_newline -= 1;
5250            }
5251
5252            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5253            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5254            let end_in_excerpt =
5255                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5256            summary.add_text_dim(
5257                &excerpt
5258                    .buffer
5259                    .text_summary_for_range::<MBD::TextDimension, _>(
5260                        start_in_excerpt..end_in_excerpt,
5261                    ),
5262            );
5263
5264            if range.end > end_before_newline {
5265                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5266            }
5267
5268            cursor.next();
5269        }
5270
5271        if range.end > *cursor.start() {
5272            summary += cursor
5273                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5274                .0;
5275            if let Some(excerpt) = cursor.item() {
5276                range.end = cmp::max(*cursor.start(), range.end);
5277
5278                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5279                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5280                summary.add_text_dim(
5281                    &excerpt
5282                        .buffer
5283                        .text_summary_for_range::<MBD::TextDimension, _>(
5284                            excerpt_start..end_in_excerpt,
5285                        ),
5286                );
5287            }
5288        }
5289
5290        summary
5291    }
5292
5293    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5294    where
5295        MBD: MultiBufferDimension
5296            + Ord
5297            + Sub<Output = MBD::TextDimension>
5298            + Sub<MBD::TextDimension, Output = MBD>
5299            + AddAssign<MBD::TextDimension>
5300            + Add<MBD::TextDimension, Output = MBD>,
5301        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5302    {
5303        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5304        let locator = self.excerpt_locator_for_id(excerpt_id);
5305        let (start, _, mut item) = self
5306            .excerpts
5307            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5308        let mut start = MBD::from_summary(&start.text);
5309        if item.is_none() && excerpt_id == ExcerptId::max() {
5310            item = self.excerpts.last();
5311            if let Some(last_summary) = self.excerpts.last_summary() {
5312                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5313            }
5314        }
5315
5316        if self.diff_transforms.is_empty() {
5317            let excerpt_start_position = ExcerptDimension(start);
5318            if let Some(excerpt) = item {
5319                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5320                    return excerpt_start_position.0;
5321                }
5322                let excerpt_buffer_start = excerpt
5323                    .range
5324                    .context
5325                    .start
5326                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5327                let excerpt_buffer_end = excerpt
5328                    .range
5329                    .context
5330                    .end
5331                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5332                let buffer_summary = anchor
5333                    .text_anchor
5334                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5335                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5336                let mut position = excerpt_start_position;
5337                if summary > excerpt_buffer_start {
5338                    position += summary - excerpt_buffer_start;
5339                }
5340
5341                position.0
5342            } else {
5343                excerpt_start_position.0
5344            }
5345        } else {
5346            let mut diff_transforms_cursor = self
5347                .diff_transforms
5348                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5349            diff_transforms_cursor.next();
5350
5351            let excerpt_start_position = ExcerptDimension(start);
5352            if let Some(excerpt) = item {
5353                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5354                    return self.resolve_summary_for_anchor(
5355                        &Anchor::min(),
5356                        excerpt_start_position,
5357                        &mut diff_transforms_cursor,
5358                    );
5359                }
5360                let excerpt_buffer_start = excerpt
5361                    .range
5362                    .context
5363                    .start
5364                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5365                let excerpt_buffer_end = excerpt
5366                    .range
5367                    .context
5368                    .end
5369                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5370                let buffer_summary = anchor
5371                    .text_anchor
5372                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5373                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5374                let mut position = excerpt_start_position;
5375                if summary > excerpt_buffer_start {
5376                    position += summary - excerpt_buffer_start;
5377                }
5378
5379                if diff_transforms_cursor.start().0 < position {
5380                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5381                }
5382                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5383            } else {
5384                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5385                self.resolve_summary_for_anchor(
5386                    &Anchor::max(),
5387                    excerpt_start_position,
5388                    &mut diff_transforms_cursor,
5389                )
5390            }
5391        }
5392    }
5393
5394    fn resolve_summary_for_anchor<MBD>(
5395        &self,
5396        anchor: &Anchor,
5397        excerpt_position: ExcerptDimension<MBD>,
5398        diff_transforms: &mut Cursor<
5399            DiffTransform,
5400            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5401        >,
5402    ) -> MBD
5403    where
5404        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5405    {
5406        loop {
5407            let transform_end_position = diff_transforms.end().0;
5408            let at_transform_end =
5409                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5410            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5411                diff_transforms.next();
5412                continue;
5413            }
5414
5415            let mut position = diff_transforms.start().1;
5416            match diff_transforms.item() {
5417                Some(DiffTransform::DeletedHunk {
5418                    buffer_id,
5419                    base_text_byte_range,
5420                    ..
5421                }) => {
5422                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5423                        && let Some(base_text) =
5424                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5425                        && diff_base_anchor.is_valid(&base_text)
5426                    {
5427                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5428                        if base_text_offset >= base_text_byte_range.start
5429                            && base_text_offset <= base_text_byte_range.end
5430                        {
5431                            let position_in_hunk = base_text
5432                                .text_summary_for_range::<MBD::TextDimension, _>(
5433                                    base_text_byte_range.start..base_text_offset,
5434                                );
5435                            position.0.add_text_dim(&position_in_hunk);
5436                        } else if at_transform_end {
5437                            diff_transforms.next();
5438                            continue;
5439                        }
5440                    }
5441                }
5442                _ => {
5443                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5444                        diff_transforms.next();
5445                        continue;
5446                    }
5447                    let overshoot = excerpt_position - diff_transforms.start().0;
5448                    position += overshoot;
5449                }
5450            }
5451
5452            return position.0;
5453        }
5454    }
5455
5456    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5457        let mut cursor = self
5458            .excerpts
5459            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5460        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5461
5462        cursor.seek(&Some(locator), Bias::Left);
5463        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5464            cursor.prev();
5465        }
5466
5467        let mut position = cursor.start().1;
5468        if let Some(excerpt) = cursor.item()
5469            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5470        {
5471            let excerpt_buffer_start = excerpt
5472                .buffer
5473                .offset_for_anchor(&excerpt.range.context.start);
5474            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5475            let buffer_position = cmp::min(
5476                excerpt_buffer_end,
5477                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5478            );
5479            if buffer_position > excerpt_buffer_start {
5480                position += buffer_position - excerpt_buffer_start;
5481            }
5482        }
5483        position
5484    }
5485
5486    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5487        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5488            excerpt_id = *replacement;
5489        }
5490        excerpt_id
5491    }
5492
5493    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5494    where
5495        MBD: MultiBufferDimension
5496            + Ord
5497            + Sub<Output = MBD::TextDimension>
5498            + AddAssign<MBD::TextDimension>,
5499        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5500        I: 'a + IntoIterator<Item = &'a Anchor>,
5501    {
5502        let mut anchors = anchors.into_iter().peekable();
5503        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5504        let mut diff_transforms_cursor = self
5505            .diff_transforms
5506            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5507        diff_transforms_cursor.next();
5508
5509        let mut summaries = Vec::new();
5510        while let Some(anchor) = anchors.peek() {
5511            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5512
5513            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5514                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5515            });
5516
5517            let locator = self.excerpt_locator_for_id(excerpt_id);
5518            cursor.seek_forward(locator, Bias::Left);
5519            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5520                cursor.prev();
5521            }
5522
5523            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5524            if let Some(excerpt) = cursor.item() {
5525                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5526                    let position = self.resolve_summary_for_anchor(
5527                        &Anchor::min(),
5528                        excerpt_start_position,
5529                        &mut diff_transforms_cursor,
5530                    );
5531                    summaries.extend(excerpt_anchors.map(|_| position));
5532                    continue;
5533                }
5534                let excerpt_buffer_start = excerpt
5535                    .range
5536                    .context
5537                    .start
5538                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5539                let excerpt_buffer_end = excerpt
5540                    .range
5541                    .context
5542                    .end
5543                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5544                for (buffer_summary, anchor) in excerpt
5545                    .buffer
5546                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5547                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5548                    )
5549                {
5550                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5551                    let mut position = excerpt_start_position;
5552                    if summary > excerpt_buffer_start {
5553                        position += summary - excerpt_buffer_start;
5554                    }
5555
5556                    if diff_transforms_cursor.start().0 < position {
5557                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5558                    }
5559
5560                    summaries.push(self.resolve_summary_for_anchor(
5561                        anchor,
5562                        position,
5563                        &mut diff_transforms_cursor,
5564                    ));
5565                }
5566            } else {
5567                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5568                let position = self.resolve_summary_for_anchor(
5569                    &Anchor::max(),
5570                    excerpt_start_position,
5571                    &mut diff_transforms_cursor,
5572                );
5573                summaries.extend(excerpt_anchors.map(|_| position));
5574            }
5575        }
5576
5577        summaries
5578    }
5579
5580    pub fn dimensions_from_points<'a, MBD>(
5581        &'a self,
5582        points: impl 'a + IntoIterator<Item = Point>,
5583    ) -> impl 'a + Iterator<Item = MBD>
5584    where
5585        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5586    {
5587        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5588        cursor.seek(&DimensionPair {
5589            key: Point::default(),
5590            value: None,
5591        });
5592        let mut points = points.into_iter();
5593        iter::from_fn(move || {
5594            let point = points.next()?;
5595
5596            cursor.seek_forward(&DimensionPair {
5597                key: point,
5598                value: None,
5599            });
5600
5601            if let Some(region) = cursor.region() {
5602                let overshoot = point - region.range.start.key;
5603                let buffer_point = region.buffer_range.start + overshoot;
5604                let mut position = region.range.start.value.unwrap();
5605                position.add_text_dim(
5606                    &region
5607                        .buffer
5608                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5609                );
5610                if point == region.range.end.key && region.has_trailing_newline {
5611                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5612                }
5613                Some(position)
5614            } else {
5615                Some(MBD::from_summary(&self.text_summary()))
5616            }
5617        })
5618    }
5619
5620    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5621    where
5622        I: 'a + IntoIterator<Item = &'a Anchor>,
5623    {
5624        let mut anchors = anchors.into_iter().enumerate().peekable();
5625        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5626        cursor.next();
5627
5628        let mut result = Vec::new();
5629
5630        while let Some((_, anchor)) = anchors.peek() {
5631            let old_excerpt_id = anchor.excerpt_id;
5632
5633            // Find the location where this anchor's excerpt should be.
5634            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5635            cursor.seek_forward(&Some(old_locator), Bias::Left);
5636
5637            let next_excerpt = cursor.item();
5638            let prev_excerpt = cursor.prev_item();
5639
5640            // Process all of the anchors for this excerpt.
5641            while let Some((anchor_ix, &anchor)) =
5642                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5643            {
5644                let mut anchor = anchor;
5645
5646                // Leave min and max anchors unchanged if invalid or
5647                // if the old excerpt still exists at this location
5648                let mut kept_position = next_excerpt
5649                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5650                    || old_excerpt_id == ExcerptId::max()
5651                    || old_excerpt_id == ExcerptId::min();
5652
5653                // If the old excerpt no longer exists at this location, then attempt to
5654                // find an equivalent position for this anchor in an adjacent excerpt.
5655                if !kept_position {
5656                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5657                        if excerpt.contains(&anchor) {
5658                            anchor.excerpt_id = excerpt.id;
5659                            kept_position = true;
5660                            break;
5661                        }
5662                    }
5663                }
5664
5665                // If there's no adjacent excerpt that contains the anchor's position,
5666                // then report that the anchor has lost its position.
5667                if !kept_position {
5668                    anchor = if let Some(excerpt) = next_excerpt {
5669                        let mut text_anchor = excerpt
5670                            .range
5671                            .context
5672                            .start
5673                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5674                        if text_anchor
5675                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5676                            .is_gt()
5677                        {
5678                            text_anchor = excerpt.range.context.end;
5679                        }
5680                        Anchor::in_buffer(excerpt.id, text_anchor)
5681                    } else if let Some(excerpt) = prev_excerpt {
5682                        let mut text_anchor = excerpt
5683                            .range
5684                            .context
5685                            .end
5686                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5687                        if text_anchor
5688                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5689                            .is_lt()
5690                        {
5691                            text_anchor = excerpt.range.context.start;
5692                        }
5693                        Anchor::in_buffer(excerpt.id, text_anchor)
5694                    } else if anchor.text_anchor.bias == Bias::Left {
5695                        Anchor::min()
5696                    } else {
5697                        Anchor::max()
5698                    };
5699                }
5700
5701                result.push((anchor_ix, anchor, kept_position));
5702            }
5703        }
5704        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5705        result
5706    }
5707
5708    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5709        self.anchor_at(position, Bias::Left)
5710    }
5711
5712    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5713        self.anchor_at(position, Bias::Right)
5714    }
5715
5716    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5717        let offset = position.to_offset(self);
5718
5719        // Find the given position in the diff transforms. Determine the corresponding
5720        // offset in the excerpts, and whether the position is within a deleted hunk.
5721        let mut diff_transforms = self
5722            .diff_transforms
5723            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5724        diff_transforms.seek(&offset, Bias::Right);
5725
5726        if offset == diff_transforms.start().0
5727            && bias == Bias::Left
5728            && let Some(prev_item) = diff_transforms.prev_item()
5729            && let DiffTransform::DeletedHunk { .. } = prev_item
5730        {
5731            diff_transforms.prev();
5732        }
5733        let offset_in_transform = offset - diff_transforms.start().0;
5734        let mut excerpt_offset = diff_transforms.start().1;
5735        let mut diff_base_anchor = None;
5736        if let Some(DiffTransform::DeletedHunk {
5737            buffer_id,
5738            base_text_byte_range,
5739            has_trailing_newline,
5740            ..
5741        }) = diff_transforms.item()
5742        {
5743            let diff = self.diffs.get(buffer_id).expect("missing diff");
5744            if offset_in_transform > base_text_byte_range.len() {
5745                debug_assert!(*has_trailing_newline);
5746                bias = Bias::Right;
5747            } else {
5748                diff_base_anchor = Some(
5749                    diff.base_text()
5750                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5751                );
5752                bias = Bias::Left;
5753            }
5754        } else {
5755            excerpt_offset += MultiBufferOffset(offset_in_transform);
5756        };
5757
5758        let mut excerpts = self
5759            .excerpts
5760            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5761        excerpts.seek(&excerpt_offset, Bias::Right);
5762        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5763            excerpts.prev();
5764        }
5765        if let Some(excerpt) = excerpts.item() {
5766            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5767            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5768                overshoot -= 1;
5769                bias = Bias::Right;
5770            }
5771
5772            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5773            let text_anchor =
5774                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5775            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5776            match diff_base_anchor {
5777                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5778                None => anchor,
5779            }
5780        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5781        {
5782            Anchor::min()
5783        } else {
5784            Anchor::max()
5785        }
5786    }
5787
5788    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5789    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5790        let (excerpt, buffer, _) = self.as_singleton()?;
5791        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5792            Some(Anchor::in_buffer(*excerpt, text_anchor))
5793        } else {
5794            None
5795        }
5796    }
5797
5798    /// Returns an anchor for the given excerpt and text anchor,
5799    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5800    pub fn anchor_range_in_excerpt(
5801        &self,
5802        excerpt_id: ExcerptId,
5803        text_anchor: Range<text::Anchor>,
5804    ) -> Option<Range<Anchor>> {
5805        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5806
5807        Some(
5808            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5809                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5810        )
5811    }
5812
5813    /// Returns an anchor for the given excerpt and text anchor,
5814    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5815    pub fn anchor_in_excerpt(
5816        &self,
5817        excerpt_id: ExcerptId,
5818        text_anchor: text::Anchor,
5819    ) -> Option<Anchor> {
5820        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5821        Self::anchor_in_excerpt_(excerpt, text_anchor)
5822    }
5823
5824    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5825    pub fn anchors_in_excerpt(
5826        &self,
5827        excerpt_id: ExcerptId,
5828        text_anchors: impl IntoIterator<Item = text::Anchor>,
5829    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5830        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5831        Some(
5832            text_anchors
5833                .into_iter()
5834                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5835        )
5836    }
5837
5838    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5839        match text_anchor.buffer_id {
5840            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5841            Some(_) => return None,
5842            None if text_anchor.is_max() || text_anchor.is_min() => {
5843                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5844            }
5845            None => return None,
5846        }
5847
5848        let context = &excerpt.range.context;
5849        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5850            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5851        {
5852            return None;
5853        }
5854
5855        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5856    }
5857
5858    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5859        Some(self.excerpt(excerpt_id)?.range.context.clone())
5860    }
5861
5862    pub fn excerpt_range_for_excerpt(
5863        &self,
5864        excerpt_id: ExcerptId,
5865    ) -> Option<ExcerptRange<text::Anchor>> {
5866        Some(self.excerpt(excerpt_id)?.range.clone())
5867    }
5868
5869    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5870        if anchor.is_min() || anchor.is_max() {
5871            // todo(lw): should be `!self.is_empty()`
5872            true
5873        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5874            excerpt.buffer.can_resolve(&anchor.text_anchor)
5875        } else {
5876            false
5877        }
5878    }
5879
5880    pub fn excerpts(
5881        &self,
5882    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5883        self.excerpts
5884            .iter()
5885            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5886    }
5887
5888    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5889    where
5890        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5891        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5892    {
5893        let excerpts = self.excerpts.cursor(());
5894        let diff_transforms = self.diff_transforms.cursor(());
5895        MultiBufferCursor {
5896            excerpts,
5897            diff_transforms,
5898            diffs: &self.diffs,
5899            cached_region: OnceCell::new(),
5900        }
5901    }
5902
5903    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5904        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5905        let mut excerpts = self
5906            .excerpts
5907            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5908        excerpts.seek(&Some(start_locator), Bias::Left);
5909        excerpts.prev();
5910
5911        let mut diff_transforms = self
5912            .diff_transforms
5913            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5914        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5915        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5916            diff_transforms.next();
5917        }
5918
5919        let excerpt = excerpts.item()?;
5920        Some(MultiBufferExcerpt {
5921            excerpt,
5922            offset: diff_transforms.start().output_dimension.0,
5923            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5924            excerpt_offset: excerpts.start().1,
5925            diff_transforms,
5926        })
5927    }
5928
5929    pub fn excerpt_boundaries_in_range<R, T>(
5930        &self,
5931        range: R,
5932    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5933    where
5934        R: RangeBounds<T>,
5935        T: ToOffset,
5936    {
5937        let start_offset;
5938        let start = match range.start_bound() {
5939            Bound::Included(start) => {
5940                start_offset = start.to_offset(self);
5941                Bound::Included(start_offset)
5942            }
5943            Bound::Excluded(_) => {
5944                panic!("not supported")
5945            }
5946            Bound::Unbounded => {
5947                start_offset = MultiBufferOffset::ZERO;
5948                Bound::Unbounded
5949            }
5950        };
5951        let end = match range.end_bound() {
5952            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5953            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5954            Bound::Unbounded => Bound::Unbounded,
5955        };
5956        let bounds = (start, end);
5957        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5958        cursor.seek(&DimensionPair {
5959            key: start_offset,
5960            value: None,
5961        });
5962
5963        if cursor
5964            .fetch_excerpt_with_range()
5965            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5966        {
5967            cursor.prev_excerpt();
5968        } else {
5969            cursor.seek_to_start_of_current_excerpt();
5970        }
5971        let mut prev_region = cursor
5972            .fetch_excerpt_with_range()
5973            .map(|(excerpt, _)| excerpt);
5974
5975        cursor.next_excerpt_forwards();
5976
5977        iter::from_fn(move || {
5978            loop {
5979                if self.singleton {
5980                    return None;
5981                }
5982
5983                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5984                cursor.next_excerpt_forwards();
5985                if !bounds.contains(&next_range.start.key) {
5986                    prev_region = Some(next_excerpt);
5987                    continue;
5988                }
5989
5990                let next_region_start = next_range.start.value.unwrap();
5991                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5992                    range.start.value.unwrap()
5993                } else {
5994                    self.max_point()
5995                };
5996
5997                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5998                    id: region.id,
5999                    buffer: region.buffer.clone(),
6000                    buffer_id: region.buffer_id,
6001                    range: region.range.clone(),
6002                    end_row: MultiBufferRow(next_region_start.row),
6003                });
6004
6005                let next = ExcerptInfo {
6006                    id: next_excerpt.id,
6007                    buffer: next_excerpt.buffer.clone(),
6008                    buffer_id: next_excerpt.buffer_id,
6009                    range: next_excerpt.range.clone(),
6010                    end_row: if next_excerpt.has_trailing_newline {
6011                        MultiBufferRow(next_region_end.row - 1)
6012                    } else {
6013                        MultiBufferRow(next_region_end.row)
6014                    },
6015                };
6016
6017                let row = MultiBufferRow(next_region_start.row);
6018
6019                prev_region = Some(next_excerpt);
6020
6021                return Some(ExcerptBoundary { row, prev, next });
6022            }
6023        })
6024    }
6025
6026    pub fn edit_count(&self) -> usize {
6027        self.edit_count
6028    }
6029
6030    pub fn non_text_state_update_count(&self) -> usize {
6031        self.non_text_state_update_count
6032    }
6033
6034    /// Returns the smallest enclosing bracket ranges containing the given range or
6035    /// None if no brackets contain range or the range is not contained in a single
6036    /// excerpt
6037    ///
6038    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6039    #[ztracing::instrument(skip_all)]
6040    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6041        &self,
6042        range: Range<T>,
6043        range_filter: Option<
6044            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6045        >,
6046    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6047        let range = range.start.to_offset(self)..range.end.to_offset(self);
6048        let mut excerpt = self.excerpt_containing(range.clone())?;
6049        let buffer = excerpt.buffer();
6050        let excerpt_buffer_range = excerpt.buffer_range();
6051
6052        // Filter to ranges contained in the excerpt
6053        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6054            excerpt_buffer_range.contains(&BufferOffset(open.start))
6055                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6056                && range_filter.is_none_or(|filter| {
6057                    filter(
6058                        buffer,
6059                        BufferOffset(open.start)..BufferOffset(close.end),
6060                        BufferOffset(close.start)..BufferOffset(close.end),
6061                    )
6062                })
6063        };
6064
6065        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6066            excerpt.map_range_to_buffer(range),
6067            Some(&range_filter),
6068        )?;
6069
6070        Some((
6071            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6072            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6073        ))
6074    }
6075
6076    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6077    /// not contained in a single excerpt
6078    pub fn enclosing_bracket_ranges<T: ToOffset>(
6079        &self,
6080        range: Range<T>,
6081    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6082    {
6083        let range = range.start.to_offset(self)..range.end.to_offset(self);
6084        let mut excerpt = self.excerpt_containing(range.clone())?;
6085
6086        Some(
6087            excerpt
6088                .buffer()
6089                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6090                .filter_map(move |pair| {
6091                    let open_range =
6092                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6093                    let close_range =
6094                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6095                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6096                        Some((
6097                            excerpt.map_range_from_buffer(open_range),
6098                            excerpt.map_range_from_buffer(close_range),
6099                        ))
6100                    } else {
6101                        None
6102                    }
6103                }),
6104        )
6105    }
6106
6107    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6108    /// not contained in a single excerpt
6109    pub fn text_object_ranges<T: ToOffset>(
6110        &self,
6111        range: Range<T>,
6112        options: TreeSitterOptions,
6113    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6114        let range = range.start.to_offset(self)..range.end.to_offset(self);
6115        self.excerpt_containing(range.clone())
6116            .map(|mut excerpt| {
6117                excerpt
6118                    .buffer()
6119                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6120                    .filter_map(move |(range, text_object)| {
6121                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6122                        if excerpt.contains_buffer_range(range.clone()) {
6123                            Some((excerpt.map_range_from_buffer(range), text_object))
6124                        } else {
6125                            None
6126                        }
6127                    })
6128            })
6129            .into_iter()
6130            .flatten()
6131    }
6132
6133    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6134    /// not contained in a single excerpt
6135    pub fn bracket_ranges<T: ToOffset>(
6136        &self,
6137        range: Range<T>,
6138    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6139    {
6140        let range = range.start.to_offset(self)..range.end.to_offset(self);
6141        let mut excerpt = self.excerpt_containing(range.clone())?;
6142        Some(
6143            excerpt
6144                .buffer()
6145                .bracket_ranges(excerpt.map_range_to_buffer(range))
6146                .filter_map(move |pair| {
6147                    let open_range =
6148                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6149                    let close_range =
6150                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6151                    excerpt
6152                        .contains_buffer_range(open_range.start..close_range.end)
6153                        .then(|| BracketMatch {
6154                            open_range: excerpt.map_range_from_buffer(open_range),
6155                            close_range: excerpt.map_range_from_buffer(close_range),
6156                            color_index: pair.color_index,
6157                            newline_only: pair.newline_only,
6158                            syntax_layer_depth: pair.syntax_layer_depth,
6159                        })
6160                })
6161                .map(BracketMatch::bracket_ranges),
6162        )
6163    }
6164
6165    pub fn redacted_ranges<'a, T: ToOffset>(
6166        &'a self,
6167        range: Range<T>,
6168        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6169    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6170        let range = range.start.to_offset(self)..range.end.to_offset(self);
6171        self.lift_buffer_metadata(range, move |buffer, range| {
6172            if redaction_enabled(buffer.file()) {
6173                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6174            } else {
6175                None
6176            }
6177        })
6178        .map(|(range, _, _)| range)
6179    }
6180
6181    pub fn runnable_ranges(
6182        &self,
6183        range: Range<Anchor>,
6184    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6185        let range = range.start.to_offset(self)..range.end.to_offset(self);
6186        self.lift_buffer_metadata(range, move |buffer, range| {
6187            Some(
6188                buffer
6189                    .runnable_ranges(range.clone())
6190                    .filter(move |runnable| {
6191                        runnable.run_range.start >= range.start
6192                            && runnable.run_range.end < range.end
6193                    })
6194                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6195            )
6196        })
6197        .map(|(run_range, runnable, _)| (run_range, runnable))
6198    }
6199
6200    pub fn line_indents(
6201        &self,
6202        start_row: MultiBufferRow,
6203        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6204    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6205        let max_point = self.max_point();
6206        let mut cursor = self.cursor::<Point, Point>();
6207        cursor.seek(&Point::new(start_row.0, 0));
6208        iter::from_fn(move || {
6209            let mut region = cursor.region()?;
6210            while !buffer_filter(&region.excerpt.buffer) {
6211                cursor.next();
6212                region = cursor.region()?;
6213            }
6214            let region = cursor.region()?;
6215            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6216            let buffer_start_row =
6217                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6218
6219            let buffer_end_row = if region.is_main_buffer
6220                && (region.has_trailing_newline || region.range.end == max_point)
6221            {
6222                region.buffer_range.end.row
6223            } else {
6224                region.buffer_range.end.row.saturating_sub(1)
6225            };
6226
6227            let line_indents = region
6228                .buffer
6229                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6230            let region_buffer_row = region.buffer_range.start.row;
6231            let region_row = region.range.start.row;
6232            let region_buffer = &region.excerpt.buffer;
6233            cursor.next();
6234            Some(line_indents.map(move |(buffer_row, indent)| {
6235                let row = region_row + (buffer_row - region_buffer_row);
6236                (MultiBufferRow(row), indent, region_buffer.as_ref())
6237            }))
6238        })
6239        .flatten()
6240    }
6241
6242    pub fn reversed_line_indents(
6243        &self,
6244        end_row: MultiBufferRow,
6245        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6246    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6247        let max_point = self.max_point();
6248        let mut cursor = self.cursor::<Point, Point>();
6249        cursor.seek(&Point::new(end_row.0, 0));
6250        iter::from_fn(move || {
6251            let mut region = cursor.region()?;
6252            while !buffer_filter(&region.excerpt.buffer) {
6253                cursor.prev();
6254                region = cursor.region()?;
6255            }
6256            let region = cursor.region()?;
6257
6258            let buffer_start_row = region.buffer_range.start.row;
6259            let buffer_end_row = if region.is_main_buffer
6260                && (region.has_trailing_newline || region.range.end == max_point)
6261            {
6262                region.buffer_range.end.row + 1
6263            } else {
6264                region.buffer_range.end.row
6265            };
6266
6267            let overshoot = end_row.0 - region.range.start.row;
6268            let buffer_end_row =
6269                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6270
6271            let line_indents = region
6272                .buffer
6273                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6274            let region_buffer_row = region.buffer_range.start.row;
6275            let region_row = region.range.start.row;
6276            let region_buffer = &region.excerpt.buffer;
6277            cursor.prev();
6278            Some(line_indents.map(move |(buffer_row, indent)| {
6279                let row = region_row + (buffer_row - region_buffer_row);
6280                (MultiBufferRow(row), indent, region_buffer.as_ref())
6281            }))
6282        })
6283        .flatten()
6284    }
6285
6286    pub async fn enclosing_indent(
6287        &self,
6288        mut target_row: MultiBufferRow,
6289    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6290        let max_row = MultiBufferRow(self.max_point().row);
6291        if target_row >= max_row {
6292            return None;
6293        }
6294
6295        let mut target_indent = self.line_indent_for_row(target_row);
6296
6297        // If the current row is at the start of an indented block, we want to return this
6298        // block as the enclosing indent.
6299        if !target_indent.is_line_empty() && target_row < max_row {
6300            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6301            if !next_line_indent.is_line_empty()
6302                && target_indent.raw_len() < next_line_indent.raw_len()
6303            {
6304                target_indent = next_line_indent;
6305                target_row.0 += 1;
6306            }
6307        }
6308
6309        const SEARCH_ROW_LIMIT: u32 = 25000;
6310        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6311        const YIELD_INTERVAL: u32 = 100;
6312
6313        let mut accessed_row_counter = 0;
6314
6315        // If there is a blank line at the current row, search for the next non indented lines
6316        if target_indent.is_line_empty() {
6317            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6318            let end =
6319                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6320
6321            let mut non_empty_line_above = None;
6322            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6323                if row < start {
6324                    break;
6325                }
6326                accessed_row_counter += 1;
6327                if accessed_row_counter == YIELD_INTERVAL {
6328                    accessed_row_counter = 0;
6329                    yield_now().await;
6330                }
6331                if !indent.is_line_empty() {
6332                    non_empty_line_above = Some((row, indent));
6333                    break;
6334                }
6335            }
6336
6337            let mut non_empty_line_below = None;
6338            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6339                if row > end {
6340                    break;
6341                }
6342                accessed_row_counter += 1;
6343                if accessed_row_counter == YIELD_INTERVAL {
6344                    accessed_row_counter = 0;
6345                    yield_now().await;
6346                }
6347                if !indent.is_line_empty() {
6348                    non_empty_line_below = Some((row, indent));
6349                    break;
6350                }
6351            }
6352
6353            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6354                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6355                    if above_indent.raw_len() >= below_indent.raw_len() {
6356                        (above_row, above_indent)
6357                    } else {
6358                        (below_row, below_indent)
6359                    }
6360                }
6361                (Some(above), None) => above,
6362                (None, Some(below)) => below,
6363                _ => return None,
6364            };
6365
6366            target_indent = indent;
6367            target_row = row;
6368        }
6369
6370        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6371        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6372
6373        let mut start_indent = None;
6374        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6375            if row < start {
6376                break;
6377            }
6378            accessed_row_counter += 1;
6379            if accessed_row_counter == YIELD_INTERVAL {
6380                accessed_row_counter = 0;
6381                yield_now().await;
6382            }
6383            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6384                start_indent = Some((row, indent));
6385                break;
6386            }
6387        }
6388        let (start_row, start_indent_size) = start_indent?;
6389
6390        let mut end_indent = (end, None);
6391        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6392            if row > end {
6393                break;
6394            }
6395            accessed_row_counter += 1;
6396            if accessed_row_counter == YIELD_INTERVAL {
6397                accessed_row_counter = 0;
6398                yield_now().await;
6399            }
6400            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6401                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6402                break;
6403            }
6404        }
6405        let (end_row, end_indent_size) = end_indent;
6406
6407        let indent = if let Some(end_indent_size) = end_indent_size {
6408            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6409                start_indent_size
6410            } else {
6411                end_indent_size
6412            }
6413        } else {
6414            start_indent_size
6415        };
6416
6417        Some((start_row..end_row, indent))
6418    }
6419
6420    pub fn indent_guides_in_range<T: ToPoint>(
6421        &self,
6422        range: Range<T>,
6423        ignore_disabled_for_language: bool,
6424        cx: &App,
6425    ) -> impl Iterator<Item = IndentGuide> {
6426        let range = range.start.to_point(self)..range.end.to_point(self);
6427        let start_row = MultiBufferRow(range.start.row);
6428        let end_row = MultiBufferRow(range.end.row);
6429
6430        let mut row_indents = self.line_indents(start_row, |buffer| {
6431            let settings =
6432                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6433            settings.indent_guides.enabled || ignore_disabled_for_language
6434        });
6435
6436        let mut result = Vec::new();
6437        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6438
6439        let mut prev_settings = None;
6440        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6441            if first_row > end_row {
6442                break;
6443            }
6444            let current_depth = indent_stack.len() as u32;
6445
6446            // Avoid retrieving the language settings repeatedly for every buffer row.
6447            if let Some((prev_buffer_id, _)) = &prev_settings
6448                && prev_buffer_id != &buffer.remote_id()
6449            {
6450                prev_settings.take();
6451            }
6452            let settings = &prev_settings
6453                .get_or_insert_with(|| {
6454                    (
6455                        buffer.remote_id(),
6456                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6457                    )
6458                })
6459                .1;
6460            let tab_size = settings.tab_size.get();
6461
6462            // When encountering empty, continue until found useful line indent
6463            // then add to the indent stack with the depth found
6464            let mut found_indent = false;
6465            let mut last_row = first_row;
6466            if line_indent.is_line_blank() {
6467                while !found_indent {
6468                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6469                        break;
6470                    };
6471                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6472                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6473                        break;
6474                    }
6475
6476                    if new_line_indent.is_line_blank() {
6477                        continue;
6478                    }
6479                    last_row = target_row.min(end_row);
6480                    line_indent = new_line_indent;
6481                    found_indent = true;
6482                    break;
6483                }
6484            } else {
6485                found_indent = true
6486            }
6487
6488            let depth = if found_indent {
6489                line_indent.len(tab_size) / tab_size
6490            } else {
6491                0
6492            };
6493
6494            match depth.cmp(&current_depth) {
6495                cmp::Ordering::Less => {
6496                    for _ in 0..(current_depth - depth) {
6497                        let mut indent = indent_stack.pop().unwrap();
6498                        if last_row != first_row {
6499                            // In this case, we landed on an empty row, had to seek forward,
6500                            // and discovered that the indent we where on is ending.
6501                            // This means that the last display row must
6502                            // be on line that ends this indent range, so we
6503                            // should display the range up to the first non-empty line
6504                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6505                        }
6506
6507                        result.push(indent)
6508                    }
6509                }
6510                cmp::Ordering::Greater => {
6511                    for next_depth in current_depth..depth {
6512                        indent_stack.push(IndentGuide {
6513                            buffer_id: buffer.remote_id(),
6514                            start_row: first_row,
6515                            end_row: last_row,
6516                            depth: next_depth,
6517                            tab_size,
6518                            settings: settings.indent_guides.clone(),
6519                        });
6520                    }
6521                }
6522                _ => {}
6523            }
6524
6525            for indent in indent_stack.iter_mut() {
6526                indent.end_row = last_row;
6527            }
6528        }
6529
6530        result.extend(indent_stack);
6531        result.into_iter()
6532    }
6533
6534    pub fn trailing_excerpt_update_count(&self) -> usize {
6535        self.trailing_excerpt_update_count
6536    }
6537
6538    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6539        self.point_to_buffer_offset(point)
6540            .and_then(|(buffer, _)| buffer.file())
6541    }
6542
6543    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6544        self.point_to_buffer_offset(offset)
6545            .and_then(|(buffer, offset)| buffer.language_at(offset))
6546    }
6547
6548    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6549        self.excerpts
6550            .first()
6551            .map(|excerpt| &excerpt.buffer)
6552            .map(|buffer| {
6553                language_settings(
6554                    buffer.language().map(|language| language.name()),
6555                    buffer.file(),
6556                    cx,
6557                )
6558            })
6559            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6560    }
6561
6562    pub fn language_settings_at<'a, T: ToOffset>(
6563        &'a self,
6564        point: T,
6565        cx: &'a App,
6566    ) -> Cow<'a, LanguageSettings> {
6567        let mut language = None;
6568        let mut file = None;
6569        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6570            language = buffer.language_at(offset);
6571            file = buffer.file();
6572        }
6573        language_settings(language.map(|l| l.name()), file, cx)
6574    }
6575
6576    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6577        self.point_to_buffer_offset(point)
6578            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6579    }
6580
6581    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6582        self.point_to_buffer_offset(point)
6583            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6584            .unwrap_or_default()
6585    }
6586
6587    pub fn language_indent_size_at<T: ToOffset>(
6588        &self,
6589        position: T,
6590        cx: &App,
6591    ) -> Option<IndentSize> {
6592        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6593        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6594    }
6595
6596    pub fn is_dirty(&self) -> bool {
6597        self.is_dirty
6598    }
6599
6600    pub fn has_deleted_file(&self) -> bool {
6601        self.has_deleted_file
6602    }
6603
6604    pub fn has_conflict(&self) -> bool {
6605        self.has_conflict
6606    }
6607
6608    pub fn has_diagnostics(&self) -> bool {
6609        self.excerpts
6610            .iter()
6611            .any(|excerpt| excerpt.buffer.has_diagnostics())
6612    }
6613
6614    pub fn diagnostic_group(
6615        &self,
6616        buffer_id: BufferId,
6617        group_id: usize,
6618    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6619        self.lift_buffer_metadata::<Point, _, _>(
6620            Point::zero()..self.max_point(),
6621            move |buffer, range| {
6622                if buffer.remote_id() != buffer_id {
6623                    return None;
6624                };
6625                Some(
6626                    buffer
6627                        .diagnostics_in_range(range, false)
6628                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6629                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6630                )
6631            },
6632        )
6633        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6634    }
6635
6636    pub fn diagnostics_in_range<'a, MBD>(
6637        &'a self,
6638        range: Range<MBD>,
6639    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6640    where
6641        MBD::TextDimension: 'a
6642            + text::ToOffset
6643            + text::FromAnchor
6644            + Sub<Output = MBD::TextDimension>
6645            + fmt::Debug
6646            + ops::Add<Output = MBD::TextDimension>
6647            + ops::AddAssign
6648            + Ord,
6649        MBD: MultiBufferDimension
6650            + Ord
6651            + Sub<Output = MBD::TextDimension>
6652            + ops::Add<MBD::TextDimension, Output = MBD>
6653            + ops::AddAssign<MBD::TextDimension>
6654            + 'a,
6655    {
6656        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6657            Some(
6658                buffer
6659                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6660                    .map(|entry| (entry.range, entry.diagnostic)),
6661            )
6662        })
6663        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6664    }
6665
6666    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6667        &'a self,
6668        range: Range<MBD>,
6669    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6670    where
6671        MBD: MultiBufferDimension
6672            + Ord
6673            + Sub<Output = MBD::TextDimension>
6674            + ops::Add<MBD::TextDimension, Output = MBD>
6675            + ops::AddAssign<MBD::TextDimension>,
6676        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6677            + ops::Add<Output = MBD::TextDimension>
6678            + text::ToOffset
6679            + text::FromAnchor
6680            + AddAssign<MBD::TextDimension>
6681            + Ord,
6682    {
6683        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6684            Some(
6685                buffer
6686                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6687                    .map(|entry| (entry.range, entry.diagnostic)),
6688            )
6689        })
6690        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6691    }
6692
6693    pub fn syntax_ancestor<T: ToOffset>(
6694        &self,
6695        range: Range<T>,
6696    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6697        let range = range.start.to_offset(self)..range.end.to_offset(self);
6698        let mut excerpt = self.excerpt_containing(range.clone())?;
6699        let node = excerpt
6700            .buffer()
6701            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6702        let node_range = node.byte_range();
6703        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6704        if !excerpt.contains_buffer_range(node_range.clone()) {
6705            return None;
6706        };
6707        Some((node, excerpt.map_range_from_buffer(node_range)))
6708    }
6709
6710    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6711        let (excerpt_id, _, buffer) = self.as_singleton()?;
6712        let outline = buffer.outline(theme);
6713        Some(Outline::new(
6714            outline
6715                .items
6716                .into_iter()
6717                .flat_map(|item| {
6718                    Some(OutlineItem {
6719                        depth: item.depth,
6720                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6721                        source_range_for_text: self
6722                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6723                        text: item.text,
6724                        highlight_ranges: item.highlight_ranges,
6725                        name_ranges: item.name_ranges,
6726                        body_range: item.body_range.and_then(|body_range| {
6727                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6728                        }),
6729                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6730                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6731                        }),
6732                    })
6733                })
6734                .collect(),
6735        ))
6736    }
6737
6738    pub fn symbols_containing<T: ToOffset>(
6739        &self,
6740        offset: T,
6741        theme: Option<&SyntaxTheme>,
6742    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6743        let anchor = self.anchor_before(offset);
6744        let excerpt @ &Excerpt {
6745            id: excerpt_id,
6746            buffer_id,
6747            ref buffer,
6748            ..
6749        } = self.excerpt(anchor.excerpt_id)?;
6750        if cfg!(debug_assertions) {
6751            match anchor.text_anchor.buffer_id {
6752                // we clearly are hitting this according to sentry, but in what situations can this occur?
6753                Some(anchor_buffer_id) => {
6754                    assert_eq!(
6755                        anchor_buffer_id, buffer_id,
6756                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6757                    )
6758                }
6759                None => assert!(anchor.is_max()),
6760            }
6761        };
6762        Some((
6763            buffer_id,
6764            buffer
6765                .symbols_containing(anchor.text_anchor, theme)
6766                .into_iter()
6767                .flat_map(|item| {
6768                    Some(OutlineItem {
6769                        depth: item.depth,
6770                        source_range_for_text: Anchor::range_in_buffer(
6771                            excerpt_id,
6772                            item.source_range_for_text,
6773                        ),
6774                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6775                        text: item.text,
6776                        highlight_ranges: item.highlight_ranges,
6777                        name_ranges: item.name_ranges,
6778                        body_range: item
6779                            .body_range
6780                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6781                        annotation_range: item
6782                            .annotation_range
6783                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6784                    })
6785                })
6786                .collect(),
6787        ))
6788    }
6789
6790    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6791        if id == ExcerptId::min() {
6792            Locator::min_ref()
6793        } else if id == ExcerptId::max() {
6794            Locator::max_ref()
6795        } else {
6796            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6797            if let Some(entry) = item
6798                && entry.id == id
6799            {
6800                return &entry.locator;
6801            }
6802            panic!("invalid excerpt id {id:?}")
6803        }
6804    }
6805
6806    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6807    fn excerpt_locators_for_ids(
6808        &self,
6809        ids: impl IntoIterator<Item = ExcerptId>,
6810    ) -> SmallVec<[Locator; 1]> {
6811        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6812        sorted_ids.sort_unstable();
6813        sorted_ids.dedup();
6814        let mut locators = SmallVec::new();
6815
6816        while sorted_ids.last() == Some(&ExcerptId::max()) {
6817            sorted_ids.pop();
6818            locators.push(Locator::max());
6819        }
6820
6821        let mut sorted_ids = sorted_ids.into_iter().peekable();
6822        locators.extend(
6823            sorted_ids
6824                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6825                .map(|_| Locator::min()),
6826        );
6827
6828        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6829        for id in sorted_ids {
6830            if cursor.seek_forward(&id, Bias::Left) {
6831                locators.push(cursor.item().unwrap().locator.clone());
6832            } else {
6833                panic!("invalid excerpt id {:?}", id);
6834            }
6835        }
6836
6837        locators.sort_unstable();
6838        locators
6839    }
6840
6841    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6842        Some(self.excerpt(excerpt_id)?.buffer_id)
6843    }
6844
6845    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6846        Some(&self.excerpt(excerpt_id)?.buffer)
6847    }
6848
6849    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6850        let mut cursor = self
6851            .excerpts
6852            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6853        let locator = self.excerpt_locator_for_id(excerpt_id);
6854        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6855        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6856            sought_exact = true;
6857            cursor.prev();
6858        } else if excerpt_id == ExcerptId::min() {
6859            sought_exact = true;
6860        }
6861        if sought_exact {
6862            let start = cursor.start().1;
6863            let end = cursor.end().1;
6864            let mut diff_transforms = self
6865                .diff_transforms
6866                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6867            diff_transforms.seek(&start, Bias::Left);
6868            let overshoot = start - diff_transforms.start().0;
6869            let start = diff_transforms.start().1 + overshoot;
6870            diff_transforms.seek(&end, Bias::Right);
6871            let overshoot = end - diff_transforms.start().0;
6872            let end = diff_transforms.start().1 + overshoot;
6873            Some(start.0..end.0)
6874        } else {
6875            None
6876        }
6877    }
6878
6879    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6880    /// to have the latest excerpt id for the one passed in and will also remap
6881    /// `ExcerptId::max()` to the corresponding excertp ID.
6882    ///
6883    /// Callers of this function should generally use the resulting excerpt's `id` field
6884    /// afterwards.
6885    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6886        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6887        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6888        let locator = self.excerpt_locator_for_id(excerpt_id);
6889        cursor.seek(&Some(locator), Bias::Left);
6890        if let Some(excerpt) = cursor.item()
6891            && excerpt.id == excerpt_id
6892        {
6893            return Some(excerpt);
6894        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6895            cursor.prev();
6896            return cursor.item();
6897        }
6898        None
6899    }
6900
6901    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6902    pub fn excerpt_containing<T: ToOffset>(
6903        &self,
6904        range: Range<T>,
6905    ) -> Option<MultiBufferExcerpt<'_>> {
6906        let range = range.start.to_offset(self)..range.end.to_offset(self);
6907        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6908        cursor.seek(&range.start);
6909
6910        let start_excerpt = cursor.excerpt()?;
6911        if range.end != range.start {
6912            cursor.seek_forward(&range.end);
6913            if cursor.excerpt()?.id != start_excerpt.id {
6914                return None;
6915            }
6916        }
6917
6918        cursor.seek_to_start_of_current_excerpt();
6919        let region = cursor.region()?;
6920        let offset = region.range.start;
6921        let buffer_offset = start_excerpt.buffer_start_offset();
6922        let excerpt_offset = *cursor.excerpts.start();
6923        Some(MultiBufferExcerpt {
6924            diff_transforms: cursor.diff_transforms,
6925            excerpt: start_excerpt,
6926            offset,
6927            buffer_offset,
6928            excerpt_offset,
6929        })
6930    }
6931
6932    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6933        if let Some(id) = anchor.text_anchor.buffer_id {
6934            return Some(id);
6935        }
6936        let excerpt = self.excerpt_containing(anchor..anchor)?;
6937        Some(excerpt.buffer_id())
6938    }
6939
6940    pub fn selections_in_range<'a>(
6941        &'a self,
6942        range: &'a Range<Anchor>,
6943        include_local: bool,
6944    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6945        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6946        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6947        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6948        cursor.seek(start_locator, Bias::Left);
6949        cursor
6950            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6951            .flat_map(move |excerpt| {
6952                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6953                if excerpt.id == range.start.excerpt_id {
6954                    query_range.start = range.start.text_anchor;
6955                }
6956                if excerpt.id == range.end.excerpt_id {
6957                    query_range.end = range.end.text_anchor;
6958                }
6959
6960                excerpt
6961                    .buffer
6962                    .selections_in_range(query_range, include_local)
6963                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6964                        selections.map(move |selection| {
6965                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6966                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6967                            if range.start.cmp(&start, self).is_gt() {
6968                                start = range.start;
6969                            }
6970                            if range.end.cmp(&end, self).is_lt() {
6971                                end = range.end;
6972                            }
6973
6974                            (
6975                                replica_id,
6976                                line_mode,
6977                                cursor_shape,
6978                                Selection {
6979                                    id: selection.id,
6980                                    start,
6981                                    end,
6982                                    reversed: selection.reversed,
6983                                    goal: selection.goal,
6984                                },
6985                            )
6986                        })
6987                    })
6988            })
6989    }
6990
6991    pub fn show_headers(&self) -> bool {
6992        self.show_headers
6993    }
6994
6995    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6996        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6997    }
6998
6999    pub fn all_diff_hunks_expanded(&self) -> bool {
7000        self.all_diff_hunks_expanded
7001    }
7002
7003    /// Visually annotates a position or range with the `Debug` representation of a value. The
7004    /// callsite of this function is used as a key - previous annotations will be removed.
7005    #[cfg(debug_assertions)]
7006    #[track_caller]
7007    pub fn debug<V, R>(&self, ranges: &R, value: V)
7008    where
7009        R: debug::ToMultiBufferDebugRanges,
7010        V: std::fmt::Debug,
7011    {
7012        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7013    }
7014
7015    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7016    /// debug annotations with the same key will be removed. The key is also used to determine the
7017    /// annotation's color.
7018    #[cfg(debug_assertions)]
7019    #[track_caller]
7020    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7021    where
7022        K: std::hash::Hash + 'static,
7023        R: debug::ToMultiBufferDebugRanges,
7024        V: std::fmt::Debug,
7025    {
7026        let text_ranges = ranges
7027            .to_multi_buffer_debug_ranges(self)
7028            .into_iter()
7029            .flat_map(|range| {
7030                self.range_to_buffer_ranges(range.start..=range.end)
7031                    .into_iter()
7032                    .map(|(buffer, range, _excerpt_id)| {
7033                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7034                    })
7035            })
7036            .collect();
7037        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7038            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7039        });
7040    }
7041
7042    fn excerpt_edits_for_diff_change(
7043        &self,
7044        buffer_state: &BufferState,
7045        diff_change_range: Range<usize>,
7046    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7047        let mut excerpt_edits = Vec::new();
7048        for locator in &buffer_state.excerpts {
7049            let mut cursor = self
7050                .excerpts
7051                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7052            cursor.seek_forward(&Some(locator), Bias::Left);
7053            if let Some(excerpt) = cursor.item()
7054                && excerpt.locator == *locator
7055            {
7056                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7057                if diff_change_range.end < excerpt_buffer_range.start
7058                    || diff_change_range.start > excerpt_buffer_range.end
7059                {
7060                    continue;
7061                }
7062                let excerpt_start = cursor.start().1;
7063                let excerpt_len = excerpt.text_summary.len;
7064                let diff_change_start_in_excerpt = diff_change_range
7065                    .start
7066                    .saturating_sub(excerpt_buffer_range.start);
7067                let diff_change_end_in_excerpt = diff_change_range
7068                    .end
7069                    .saturating_sub(excerpt_buffer_range.start);
7070                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7071                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7072                excerpt_edits.push(Edit {
7073                    old: edit_start..edit_end,
7074                    new: edit_start..edit_end,
7075                });
7076            }
7077        }
7078        excerpt_edits
7079    }
7080}
7081
7082#[cfg(any(test, feature = "test-support"))]
7083impl MultiBufferSnapshot {
7084    pub fn random_byte_range(
7085        &self,
7086        start_offset: MultiBufferOffset,
7087        rng: &mut impl rand::Rng,
7088    ) -> Range<MultiBufferOffset> {
7089        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7090        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7091        start..end
7092    }
7093
7094    #[cfg(any(test, feature = "test-support"))]
7095    fn check_invariants(&self) {
7096        let excerpts = self.excerpts.items(());
7097        let excerpt_ids = self.excerpt_ids.items(());
7098
7099        for (ix, excerpt) in excerpts.iter().enumerate() {
7100            if ix == 0 {
7101                if excerpt.locator <= Locator::min() {
7102                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7103                }
7104            } else if excerpt.locator <= excerpts[ix - 1].locator {
7105                panic!("excerpts are out-of-order: {:?}", excerpts);
7106            }
7107        }
7108
7109        for (ix, entry) in excerpt_ids.iter().enumerate() {
7110            if ix == 0 {
7111                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7112                    panic!("invalid first excerpt id {:?}", entry.id);
7113                }
7114            } else if entry.id <= excerpt_ids[ix - 1].id {
7115                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7116            }
7117        }
7118
7119        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7120            panic!(
7121                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7122                self.excerpts.summary().text,
7123                self.diff_transforms.summary().input,
7124                self.diff_transforms.items(()),
7125            );
7126        }
7127
7128        let mut prev_transform: Option<&DiffTransform> = None;
7129        for item in self.diff_transforms.iter() {
7130            if let DiffTransform::BufferContent {
7131                summary,
7132                inserted_hunk_info,
7133            } = item
7134            {
7135                if let Some(DiffTransform::BufferContent {
7136                    inserted_hunk_info: prev_inserted_hunk_info,
7137                    ..
7138                }) = prev_transform
7139                    && *inserted_hunk_info == *prev_inserted_hunk_info
7140                {
7141                    panic!(
7142                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7143                        self.diff_transforms.items(())
7144                    );
7145                }
7146                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7147                    panic!("empty buffer content transform");
7148                }
7149            }
7150            prev_transform = Some(item);
7151        }
7152    }
7153}
7154
7155impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7156where
7157    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7158    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7159{
7160    #[instrument(skip_all)]
7161    fn seek(&mut self, position: &MBD) {
7162        let position = OutputDimension(*position);
7163        self.cached_region.take();
7164        self.diff_transforms.seek(&position, Bias::Right);
7165        if self.diff_transforms.item().is_none()
7166            && self.diff_transforms.start().output_dimension == position
7167        {
7168            self.diff_transforms.prev();
7169        }
7170
7171        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7172        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7173            let overshoot = position - self.diff_transforms.start().output_dimension;
7174            excerpt_position += overshoot;
7175        }
7176
7177        self.excerpts.seek(&excerpt_position, Bias::Right);
7178        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7179            self.excerpts.prev();
7180        }
7181    }
7182
7183    fn seek_forward(&mut self, position: &MBD) {
7184        let position = OutputDimension(*position);
7185        self.cached_region.take();
7186        self.diff_transforms.seek_forward(&position, Bias::Right);
7187        if self.diff_transforms.item().is_none()
7188            && self.diff_transforms.start().output_dimension == position
7189        {
7190            self.diff_transforms.prev();
7191        }
7192
7193        let overshoot = position - self.diff_transforms.start().output_dimension;
7194        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7195        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7196            excerpt_position += overshoot;
7197        }
7198
7199        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7200        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7201            self.excerpts.prev();
7202        }
7203    }
7204
7205    fn next_excerpt(&mut self) {
7206        self.excerpts.next();
7207        self.seek_to_start_of_current_excerpt();
7208    }
7209
7210    fn prev_excerpt(&mut self) {
7211        self.excerpts.prev();
7212        self.seek_to_start_of_current_excerpt();
7213    }
7214
7215    fn seek_to_start_of_current_excerpt(&mut self) {
7216        self.cached_region.take();
7217
7218        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7219            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7220            && self.diff_transforms.next_item().is_some()
7221        {
7222            self.diff_transforms.next();
7223        }
7224    }
7225
7226    fn next_excerpt_forwards(&mut self) {
7227        self.excerpts.next();
7228        self.seek_to_start_of_current_excerpt_forward();
7229    }
7230
7231    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7232        self.cached_region.take();
7233
7234        if self
7235            .diff_transforms
7236            .seek_forward(self.excerpts.start(), Bias::Left)
7237            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7238            && self.diff_transforms.next_item().is_some()
7239        {
7240            self.diff_transforms.next();
7241        }
7242    }
7243
7244    fn next(&mut self) {
7245        self.cached_region.take();
7246        match self
7247            .diff_transforms
7248            .end()
7249            .excerpt_dimension
7250            .cmp(&self.excerpts.end())
7251        {
7252            cmp::Ordering::Less => self.diff_transforms.next(),
7253            cmp::Ordering::Greater => self.excerpts.next(),
7254            cmp::Ordering::Equal => {
7255                self.diff_transforms.next();
7256                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7257                    || self.diff_transforms.item().is_none()
7258                {
7259                    self.excerpts.next();
7260                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7261                    self.diff_transforms.item()
7262                    && self
7263                        .excerpts
7264                        .item()
7265                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7266                {
7267                    self.excerpts.next();
7268                }
7269            }
7270        }
7271    }
7272
7273    fn prev(&mut self) {
7274        self.cached_region.take();
7275        match self
7276            .diff_transforms
7277            .start()
7278            .excerpt_dimension
7279            .cmp(self.excerpts.start())
7280        {
7281            cmp::Ordering::Less => self.excerpts.prev(),
7282            cmp::Ordering::Greater => self.diff_transforms.prev(),
7283            cmp::Ordering::Equal => {
7284                self.diff_transforms.prev();
7285                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7286                    || self.diff_transforms.item().is_none()
7287                {
7288                    self.excerpts.prev();
7289                }
7290            }
7291        }
7292    }
7293
7294    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7295        self.cached_region
7296            .get_or_init(|| self.build_region())
7297            .as_ref()
7298    }
7299
7300    fn is_at_start_of_excerpt(&mut self) -> bool {
7301        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7302            return false;
7303        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7304            return true;
7305        }
7306
7307        self.diff_transforms.prev();
7308        let prev_transform = self.diff_transforms.item();
7309        self.diff_transforms.next();
7310
7311        prev_transform.is_none_or(|next_transform| {
7312            matches!(next_transform, DiffTransform::BufferContent { .. })
7313        })
7314    }
7315
7316    fn is_at_end_of_excerpt(&self) -> bool {
7317        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7318            return false;
7319        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7320            || self.diff_transforms.item().is_none()
7321        {
7322            return true;
7323        }
7324
7325        let next_transform = self.diff_transforms.next_item();
7326        next_transform.is_none_or(|next_transform| match next_transform {
7327            DiffTransform::BufferContent { .. } => true,
7328            DiffTransform::DeletedHunk { hunk_info, .. } => self
7329                .excerpts
7330                .item()
7331                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7332        })
7333    }
7334
7335    fn main_buffer_position(&self) -> Option<BD> {
7336        let excerpt = self.excerpts.item()?;
7337        let buffer = &excerpt.buffer;
7338        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7339        let mut buffer_start = buffer_context_start;
7340        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7341        buffer_start += overshoot;
7342        Some(buffer_start)
7343    }
7344
7345    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7346        let excerpt = self.excerpts.item()?;
7347        match self.diff_transforms.item()? {
7348            DiffTransform::DeletedHunk {
7349                buffer_id,
7350                base_text_byte_range,
7351                has_trailing_newline,
7352                hunk_info,
7353                ..
7354            } => {
7355                let diff = self.diffs.get(buffer_id)?;
7356                let buffer = diff.base_text();
7357                let mut rope_cursor = buffer.as_rope().cursor(0);
7358                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7359                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7360                let mut buffer_end = buffer_start;
7361                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7362                let start = self.diff_transforms.start().output_dimension.0;
7363                let end = self.diff_transforms.end().output_dimension.0;
7364                Some(MultiBufferRegion {
7365                    buffer,
7366                    excerpt,
7367                    has_trailing_newline: *has_trailing_newline,
7368                    is_main_buffer: false,
7369                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7370                        hunk_info.hunk_secondary_status,
7371                    )),
7372                    buffer_range: buffer_start..buffer_end,
7373                    range: start..end,
7374                })
7375            }
7376            DiffTransform::BufferContent {
7377                inserted_hunk_info, ..
7378            } => {
7379                let buffer = &excerpt.buffer;
7380                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7381
7382                let mut start = self.diff_transforms.start().output_dimension.0;
7383                let mut buffer_start = buffer_context_start;
7384                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7385                    let overshoot =
7386                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7387                    start += overshoot;
7388                } else {
7389                    let overshoot =
7390                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7391                    buffer_start += overshoot;
7392                }
7393
7394                let mut end;
7395                let mut buffer_end;
7396                let has_trailing_newline;
7397                let transform_end = self.diff_transforms.end();
7398                if transform_end.excerpt_dimension < self.excerpts.end() {
7399                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7400                    end = transform_end.output_dimension.0;
7401                    buffer_end = buffer_context_start;
7402                    buffer_end += overshoot;
7403                    has_trailing_newline = false;
7404                } else {
7405                    let overshoot =
7406                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7407                    end = self.diff_transforms.start().output_dimension.0;
7408                    end += overshoot;
7409                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7410                    has_trailing_newline = excerpt.has_trailing_newline;
7411                };
7412
7413                let diff_hunk_status = inserted_hunk_info.map(|info| {
7414                    if info.is_logically_deleted {
7415                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7416                    } else {
7417                        DiffHunkStatus::added(info.hunk_secondary_status)
7418                    }
7419                });
7420
7421                Some(MultiBufferRegion {
7422                    buffer,
7423                    excerpt,
7424                    has_trailing_newline,
7425                    is_main_buffer: true,
7426                    diff_hunk_status,
7427                    buffer_range: buffer_start..buffer_end,
7428                    range: start..end,
7429                })
7430            }
7431        }
7432    }
7433
7434    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7435        let excerpt = self.excerpts.item()?;
7436        match self.diff_transforms.item()? {
7437            &DiffTransform::DeletedHunk { .. } => {
7438                let start = self.diff_transforms.start().output_dimension.0;
7439                let end = self.diff_transforms.end().output_dimension.0;
7440                Some((excerpt, start..end))
7441            }
7442            DiffTransform::BufferContent { .. } => {
7443                let mut start = self.diff_transforms.start().output_dimension.0;
7444                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7445                    let overshoot =
7446                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7447                    start += overshoot;
7448                }
7449
7450                let mut end;
7451                let transform_end = self.diff_transforms.end();
7452                if transform_end.excerpt_dimension < self.excerpts.end() {
7453                    end = transform_end.output_dimension.0;
7454                } else {
7455                    let overshoot =
7456                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7457                    end = self.diff_transforms.start().output_dimension.0;
7458                    end += overshoot;
7459                };
7460
7461                Some((excerpt, start..end))
7462            }
7463        }
7464    }
7465
7466    fn excerpt(&self) -> Option<&'a Excerpt> {
7467        self.excerpts.item()
7468    }
7469}
7470
7471impl Excerpt {
7472    fn new(
7473        id: ExcerptId,
7474        locator: Locator,
7475        buffer_id: BufferId,
7476        buffer: Arc<BufferSnapshot>,
7477        range: ExcerptRange<text::Anchor>,
7478        has_trailing_newline: bool,
7479    ) -> Self {
7480        Excerpt {
7481            id,
7482            locator,
7483            max_buffer_row: range.context.end.to_point(&buffer).row,
7484            text_summary: buffer
7485                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7486            buffer_id,
7487            buffer,
7488            range,
7489            has_trailing_newline,
7490        }
7491    }
7492
7493    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7494        let content_start = self.range.context.start.to_offset(&self.buffer);
7495        let chunks_start = content_start + range.start;
7496        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7497
7498        let has_footer = self.has_trailing_newline
7499            && range.start <= self.text_summary.len
7500            && range.end > self.text_summary.len;
7501
7502        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7503
7504        ExcerptChunks {
7505            excerpt_id: self.id,
7506            content_chunks,
7507            has_footer,
7508        }
7509    }
7510
7511    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7512        let content_start = self.range.context.start.to_offset(&self.buffer);
7513        let chunks_start = content_start + range.start;
7514        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7515        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7516        excerpt_chunks.has_footer = self.has_trailing_newline
7517            && range.start <= self.text_summary.len
7518            && range.end > self.text_summary.len;
7519    }
7520
7521    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7522        if text_anchor
7523            .cmp(&self.range.context.start, &self.buffer)
7524            .is_lt()
7525        {
7526            self.range.context.start
7527        } else if text_anchor
7528            .cmp(&self.range.context.end, &self.buffer)
7529            .is_gt()
7530        {
7531            self.range.context.end
7532        } else {
7533            text_anchor
7534        }
7535    }
7536
7537    fn contains(&self, anchor: &Anchor) -> bool {
7538        (anchor.text_anchor.buffer_id == None
7539            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7540            && self
7541                .range
7542                .context
7543                .start
7544                .cmp(&anchor.text_anchor, &self.buffer)
7545                .is_le()
7546            && self
7547                .range
7548                .context
7549                .end
7550                .cmp(&anchor.text_anchor, &self.buffer)
7551                .is_ge()
7552    }
7553
7554    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7555    fn buffer_start_offset(&self) -> BufferOffset {
7556        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7557    }
7558
7559    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7560    fn buffer_end_offset(&self) -> BufferOffset {
7561        self.buffer_start_offset() + self.text_summary.len
7562    }
7563}
7564
7565impl<'a> MultiBufferExcerpt<'a> {
7566    pub fn id(&self) -> ExcerptId {
7567        self.excerpt.id
7568    }
7569
7570    pub fn buffer_id(&self) -> BufferId {
7571        self.excerpt.buffer_id
7572    }
7573
7574    pub fn start_anchor(&self) -> Anchor {
7575        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7576    }
7577
7578    pub fn end_anchor(&self) -> Anchor {
7579        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7580    }
7581
7582    pub fn buffer(&self) -> &'a BufferSnapshot {
7583        &self.excerpt.buffer
7584    }
7585
7586    pub fn buffer_range(&self) -> Range<BufferOffset> {
7587        self.buffer_offset
7588            ..BufferOffset(
7589                self.excerpt
7590                    .range
7591                    .context
7592                    .end
7593                    .to_offset(&self.excerpt.buffer.text),
7594            )
7595    }
7596
7597    pub fn start_offset(&self) -> MultiBufferOffset {
7598        self.offset
7599    }
7600
7601    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7602    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7603        self.map_range_to_buffer(offset..offset).start
7604    }
7605
7606    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7607    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7608        self.diff_transforms
7609            .seek(&OutputDimension(range.start), Bias::Right);
7610        let start = self.map_offset_to_buffer_internal(range.start);
7611        let end = if range.end > range.start {
7612            self.diff_transforms
7613                .seek_forward(&OutputDimension(range.end), Bias::Right);
7614            self.map_offset_to_buffer_internal(range.end)
7615        } else {
7616            start
7617        };
7618        start..end
7619    }
7620
7621    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7622        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7623        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7624            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7625        };
7626        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7627        self.buffer_offset + offset_in_excerpt
7628    }
7629
7630    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7631    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7632        self.map_range_from_buffer(buffer_offset..buffer_offset)
7633            .start
7634    }
7635
7636    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7637    pub fn map_range_from_buffer(
7638        &mut self,
7639        buffer_range: Range<BufferOffset>,
7640    ) -> Range<MultiBufferOffset> {
7641        if buffer_range.start < self.buffer_offset {
7642            log::warn!(
7643                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7644            );
7645            return self.offset..self.offset;
7646        }
7647        let overshoot = buffer_range.start - self.buffer_offset;
7648        let excerpt_offset = self.excerpt_offset + overshoot;
7649        let excerpt_seek_dim = excerpt_offset;
7650        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7651        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7652            log::warn!(
7653                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7654            );
7655            return self.offset..self.offset;
7656        }
7657        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7658        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7659
7660        let end = if buffer_range.start < buffer_range.end {
7661            let overshoot = buffer_range.end - self.buffer_offset;
7662            let excerpt_offset = self.excerpt_offset + overshoot;
7663            let excerpt_seek_dim = excerpt_offset;
7664            self.diff_transforms
7665                .seek_forward(&excerpt_seek_dim, Bias::Right);
7666            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7667            // todo(lw): Clamp end to the excerpt boundaries
7668            self.diff_transforms.start().output_dimension.0 + overshoot
7669        } else {
7670            start
7671        };
7672
7673        start..end
7674    }
7675
7676    /// Returns true if the entirety of the given range is in the buffer's excerpt
7677    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7678        range.start >= self.excerpt.buffer_start_offset()
7679            && range.end <= self.excerpt.buffer_end_offset()
7680    }
7681
7682    /// Returns true if any part of the given range is in the buffer's excerpt
7683    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7684        range.start <= self.excerpt.buffer_end_offset()
7685            && range.end >= self.excerpt.buffer_start_offset()
7686    }
7687
7688    pub fn max_buffer_row(&self) -> u32 {
7689        self.excerpt.max_buffer_row
7690    }
7691}
7692
7693impl ExcerptId {
7694    pub fn min() -> Self {
7695        Self(0)
7696    }
7697
7698    pub fn max() -> Self {
7699        Self(u32::MAX)
7700    }
7701
7702    pub fn to_proto(self) -> u64 {
7703        self.0 as _
7704    }
7705
7706    pub fn from_proto(proto: u64) -> Self {
7707        Self(proto as _)
7708    }
7709
7710    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7711        let a = snapshot.excerpt_locator_for_id(*self);
7712        let b = snapshot.excerpt_locator_for_id(*other);
7713        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7714    }
7715}
7716
7717impl From<ExcerptId> for usize {
7718    fn from(val: ExcerptId) -> Self {
7719        val.0 as usize
7720    }
7721}
7722
7723impl fmt::Debug for Excerpt {
7724    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7725        f.debug_struct("Excerpt")
7726            .field("id", &self.id)
7727            .field("locator", &self.locator)
7728            .field("buffer_id", &self.buffer_id)
7729            .field("range", &self.range)
7730            .field("text_summary", &self.text_summary)
7731            .field("has_trailing_newline", &self.has_trailing_newline)
7732            .finish()
7733    }
7734}
7735
7736impl sum_tree::Item for Excerpt {
7737    type Summary = ExcerptSummary;
7738
7739    fn summary(&self, _cx: ()) -> Self::Summary {
7740        let mut text = self.text_summary;
7741        if self.has_trailing_newline {
7742            text += TextSummary::from("\n");
7743        }
7744        ExcerptSummary {
7745            excerpt_id: self.id,
7746            excerpt_locator: self.locator.clone(),
7747            widest_line_number: self.max_buffer_row,
7748            text: text.into(),
7749        }
7750    }
7751}
7752
7753impl sum_tree::Item for ExcerptIdMapping {
7754    type Summary = ExcerptId;
7755
7756    fn summary(&self, _cx: ()) -> Self::Summary {
7757        self.id
7758    }
7759}
7760
7761impl sum_tree::KeyedItem for ExcerptIdMapping {
7762    type Key = ExcerptId;
7763
7764    fn key(&self) -> Self::Key {
7765        self.id
7766    }
7767}
7768
7769impl DiffTransform {
7770    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7771        match self {
7772            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7773            DiffTransform::BufferContent {
7774                inserted_hunk_info, ..
7775            } => *inserted_hunk_info,
7776        }
7777    }
7778}
7779
7780impl sum_tree::Item for DiffTransform {
7781    type Summary = DiffTransformSummary;
7782
7783    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7784        match self {
7785            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7786                input: *summary,
7787                output: *summary,
7788            },
7789            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7790                input: MBTextSummary::default(),
7791                output: summary.into(),
7792            },
7793        }
7794    }
7795}
7796
7797impl DiffTransformSummary {
7798    fn excerpt_len(&self) -> ExcerptOffset {
7799        ExcerptDimension(self.input.len)
7800    }
7801}
7802
7803impl sum_tree::ContextLessSummary for DiffTransformSummary {
7804    fn zero() -> Self {
7805        DiffTransformSummary {
7806            input: MBTextSummary::default(),
7807            output: MBTextSummary::default(),
7808        }
7809    }
7810
7811    fn add_summary(&mut self, other: &Self) {
7812        self.input += other.input;
7813        self.output += other.output;
7814    }
7815}
7816
7817impl sum_tree::ContextLessSummary for ExcerptId {
7818    fn zero() -> Self {
7819        Self(0)
7820    }
7821
7822    fn add_summary(&mut self, summary: &Self) {
7823        *self = cmp::max(*self, *summary);
7824    }
7825}
7826
7827impl sum_tree::ContextLessSummary for ExcerptSummary {
7828    fn zero() -> Self {
7829        Self::default()
7830    }
7831
7832    fn add_summary(&mut self, summary: &Self) {
7833        debug_assert!(
7834            summary.excerpt_locator > self.excerpt_locator
7835                || self.excerpt_locator == Locator::min(),
7836            "Excerpt locators must be in ascending order: {:?} > {:?}",
7837            summary.excerpt_locator,
7838            self.excerpt_locator
7839        );
7840        self.excerpt_locator = summary.excerpt_locator.clone();
7841        self.text += summary.text;
7842        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7843    }
7844}
7845
7846impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7847    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7848        Ord::cmp(&Some(self), cursor_location)
7849    }
7850}
7851
7852impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7853    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7854        Ord::cmp(self, &cursor_location.excerpt_locator)
7855    }
7856}
7857
7858impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7859where
7860    MBD: MultiBufferDimension + Default,
7861{
7862    fn zero(_: ()) -> Self {
7863        ExcerptDimension(MBD::default())
7864    }
7865
7866    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7867        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7868    }
7869}
7870
7871impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7872    fn zero(_cx: ()) -> Self {
7873        Default::default()
7874    }
7875
7876    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7877        *self = Some(&summary.excerpt_locator);
7878    }
7879}
7880
7881impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7882    fn zero(_cx: ()) -> Self {
7883        Default::default()
7884    }
7885
7886    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7887        *self = Some(summary.excerpt_id);
7888    }
7889}
7890
7891#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7892struct OutputDimension<T>(T);
7893
7894impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7895    fn eq(&self, other: &T) -> bool {
7896        self.0 == *other
7897    }
7898}
7899
7900impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7901    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7902        self.0.partial_cmp(other)
7903    }
7904}
7905
7906impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7907where
7908    T: ops::Sub<U, Output = R>,
7909{
7910    type Output = R;
7911
7912    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7913        self.0 - other.0
7914    }
7915}
7916
7917impl<R, T, U> ops::Add<U> for OutputDimension<T>
7918where
7919    T: ops::Add<U, Output = R>,
7920{
7921    type Output = OutputDimension<R>;
7922
7923    fn add(self, other: U) -> Self::Output {
7924        OutputDimension(self.0 + other)
7925    }
7926}
7927
7928impl<T, U> AddAssign<U> for OutputDimension<T>
7929where
7930    T: AddAssign<U>,
7931{
7932    fn add_assign(&mut self, other: U) {
7933        self.0 += other;
7934    }
7935}
7936
7937impl<T, U> SubAssign<U> for OutputDimension<T>
7938where
7939    T: SubAssign<U>,
7940{
7941    fn sub_assign(&mut self, other: U) {
7942        self.0 -= other;
7943    }
7944}
7945
7946#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7947struct ExcerptDimension<T>(T);
7948
7949impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7950    fn eq(&self, other: &T) -> bool {
7951        self.0 == *other
7952    }
7953}
7954
7955impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7956    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7957        self.0.partial_cmp(other)
7958    }
7959}
7960
7961impl ExcerptOffset {
7962    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7963        self.0.saturating_sub(other.0)
7964    }
7965}
7966
7967impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7968where
7969    T: ops::Sub<U, Output = R>,
7970{
7971    type Output = R;
7972
7973    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7974        self.0 - other.0
7975    }
7976}
7977
7978impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7979where
7980    T: ops::Add<U, Output = R>,
7981{
7982    type Output = ExcerptDimension<R>;
7983
7984    fn add(self, other: U) -> Self::Output {
7985        ExcerptDimension(self.0 + other)
7986    }
7987}
7988
7989impl<T, U> AddAssign<U> for ExcerptDimension<T>
7990where
7991    T: AddAssign<U>,
7992{
7993    fn add_assign(&mut self, other: U) {
7994        self.0 += other;
7995    }
7996}
7997
7998impl<T, U> SubAssign<U> for ExcerptDimension<T>
7999where
8000    T: SubAssign<U>,
8001{
8002    fn sub_assign(&mut self, other: U) {
8003        self.0 -= other;
8004    }
8005}
8006
8007impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8008    fn zero(_: ()) -> Self {
8009        MultiBufferOffset::ZERO
8010    }
8011
8012    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8013        *self += summary.output.len;
8014    }
8015}
8016
8017impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8018    for ExcerptDimension<MBD>
8019where
8020    MBD: MultiBufferDimension + Ord,
8021{
8022    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8023        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8024    }
8025}
8026
8027impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8028    for ExcerptDimension<MBD>
8029where
8030    MBD: MultiBufferDimension + Ord,
8031{
8032    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8033        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8034    }
8035}
8036
8037impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8038    for ExcerptDimension<MBD>
8039{
8040    fn zero(_: ()) -> Self {
8041        ExcerptDimension(MBD::default())
8042    }
8043
8044    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8045        self.0.add_mb_text_summary(&summary.input)
8046    }
8047}
8048
8049impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8050    for OutputDimension<MBD>
8051where
8052    MBD: MultiBufferDimension + Ord,
8053{
8054    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8055        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8056    }
8057}
8058
8059impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8060    for OutputDimension<MBD>
8061{
8062    fn zero(_: ()) -> Self {
8063        OutputDimension(MBD::default())
8064    }
8065
8066    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8067        self.0.add_mb_text_summary(&summary.output)
8068    }
8069}
8070
8071impl MultiBufferRows<'_> {
8072    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8073        self.point = Point::new(row, 0);
8074        self.cursor.seek(&self.point);
8075    }
8076}
8077
8078impl Iterator for MultiBufferRows<'_> {
8079    type Item = RowInfo;
8080
8081    fn next(&mut self) -> Option<Self::Item> {
8082        if self.is_empty && self.point.row == 0 {
8083            self.point += Point::new(1, 0);
8084            return Some(RowInfo {
8085                buffer_id: None,
8086                buffer_row: Some(0),
8087                multibuffer_row: Some(MultiBufferRow(0)),
8088                diff_status: None,
8089                expand_info: None,
8090                wrapped_buffer_row: None,
8091            });
8092        }
8093
8094        let mut region = self.cursor.region()?.clone();
8095        while self.point >= region.range.end {
8096            self.cursor.next();
8097            if let Some(next_region) = self.cursor.region() {
8098                region = next_region.clone();
8099            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8100                let multibuffer_row = MultiBufferRow(self.point.row);
8101                let last_excerpt = self
8102                    .cursor
8103                    .excerpts
8104                    .item()
8105                    .or(self.cursor.excerpts.prev_item())?;
8106                let last_row = last_excerpt
8107                    .range
8108                    .context
8109                    .end
8110                    .to_point(&last_excerpt.buffer)
8111                    .row;
8112
8113                let first_row = last_excerpt
8114                    .range
8115                    .context
8116                    .start
8117                    .to_point(&last_excerpt.buffer)
8118                    .row;
8119
8120                let expand_info = if self.is_singleton {
8121                    None
8122                } else {
8123                    let needs_expand_up = first_row == last_row
8124                        && last_row > 0
8125                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8126                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8127
8128                    if needs_expand_up && needs_expand_down {
8129                        Some(ExpandExcerptDirection::UpAndDown)
8130                    } else if needs_expand_up {
8131                        Some(ExpandExcerptDirection::Up)
8132                    } else if needs_expand_down {
8133                        Some(ExpandExcerptDirection::Down)
8134                    } else {
8135                        None
8136                    }
8137                    .map(|direction| ExpandInfo {
8138                        direction,
8139                        excerpt_id: last_excerpt.id,
8140                    })
8141                };
8142                self.point += Point::new(1, 0);
8143                return Some(RowInfo {
8144                    buffer_id: Some(last_excerpt.buffer_id),
8145                    buffer_row: Some(last_row),
8146                    multibuffer_row: Some(multibuffer_row),
8147                    diff_status: None,
8148                    wrapped_buffer_row: None,
8149                    expand_info,
8150                });
8151            } else {
8152                return None;
8153            };
8154        }
8155
8156        let overshoot = self.point - region.range.start;
8157        let buffer_point = region.buffer_range.start + overshoot;
8158        let expand_info = if self.is_singleton {
8159            None
8160        } else {
8161            let needs_expand_up = self.point.row == region.range.start.row
8162                && self.cursor.is_at_start_of_excerpt()
8163                && buffer_point.row > 0;
8164            let needs_expand_down = (region.excerpt.has_trailing_newline
8165                && self.point.row + 1 == region.range.end.row
8166                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8167                && self.cursor.is_at_end_of_excerpt()
8168                && buffer_point.row < region.buffer.max_point().row;
8169
8170            if needs_expand_up && needs_expand_down {
8171                Some(ExpandExcerptDirection::UpAndDown)
8172            } else if needs_expand_up {
8173                Some(ExpandExcerptDirection::Up)
8174            } else if needs_expand_down {
8175                Some(ExpandExcerptDirection::Down)
8176            } else {
8177                None
8178            }
8179            .map(|direction| ExpandInfo {
8180                direction,
8181                excerpt_id: region.excerpt.id,
8182            })
8183        };
8184
8185        let result = Some(RowInfo {
8186            buffer_id: Some(region.buffer.remote_id()),
8187            buffer_row: Some(buffer_point.row),
8188            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8189            diff_status: region
8190                .diff_hunk_status
8191                .filter(|_| self.point < region.range.end),
8192            expand_info,
8193            wrapped_buffer_row: None,
8194        });
8195        self.point += Point::new(1, 0);
8196        result
8197    }
8198}
8199
8200impl<'a> MultiBufferChunks<'a> {
8201    pub fn offset(&self) -> MultiBufferOffset {
8202        self.range.start
8203    }
8204
8205    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8206        self.diff_transforms.seek(&range.end, Bias::Right);
8207        let mut excerpt_end = self.diff_transforms.start().1;
8208        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8209            let overshoot = range.end - self.diff_transforms.start().0;
8210            excerpt_end += overshoot;
8211        }
8212
8213        self.diff_transforms.seek(&range.start, Bias::Right);
8214        let mut excerpt_start = self.diff_transforms.start().1;
8215        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8216            let overshoot = range.start - self.diff_transforms.start().0;
8217            excerpt_start += overshoot;
8218        }
8219
8220        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8221        self.buffer_chunk.take();
8222        self.range = range;
8223    }
8224
8225    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8226        self.excerpt_offset_range = new_range.clone();
8227        self.excerpts.seek(&new_range.start, Bias::Right);
8228        if let Some(excerpt) = self.excerpts.item() {
8229            let excerpt_start = *self.excerpts.start();
8230            if let Some(excerpt_chunks) = self
8231                .excerpt_chunks
8232                .as_mut()
8233                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8234            {
8235                excerpt.seek_chunks(
8236                    excerpt_chunks,
8237                    (self.excerpt_offset_range.start - excerpt_start)
8238                        ..(self.excerpt_offset_range.end - excerpt_start),
8239                );
8240            } else {
8241                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8242                    (self.excerpt_offset_range.start - excerpt_start)
8243                        ..(self.excerpt_offset_range.end - excerpt_start),
8244                    self.language_aware,
8245                ));
8246            }
8247        } else {
8248            self.excerpt_chunks = None;
8249        }
8250    }
8251
8252    #[ztracing::instrument(skip_all)]
8253    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8254        loop {
8255            if self.excerpt_offset_range.is_empty() {
8256                return None;
8257            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8258                self.excerpt_offset_range.start += chunk.text.len();
8259                return Some(chunk);
8260            } else {
8261                self.excerpts.next();
8262                let excerpt = self.excerpts.item()?;
8263                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8264                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8265                    self.language_aware,
8266                ));
8267            }
8268        }
8269    }
8270}
8271
8272impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8273    type Item = &'a str;
8274
8275    fn next(&mut self) -> Option<Self::Item> {
8276        let mut region = self.cursor.region()?;
8277        if self.offset == region.range.start {
8278            self.cursor.prev();
8279            region = self.cursor.region()?;
8280            let start_overshoot = self.start.saturating_sub(region.range.start);
8281            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8282                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8283            ));
8284        }
8285
8286        if self.offset == region.range.end && region.has_trailing_newline {
8287            self.offset -= 1;
8288            Some("\n")
8289        } else {
8290            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8291            self.offset -= chunk.len();
8292            Some(chunk)
8293        }
8294    }
8295}
8296
8297impl<'a> Iterator for MultiBufferChunks<'a> {
8298    type Item = Chunk<'a>;
8299
8300    #[ztracing::instrument(skip_all)]
8301    fn next(&mut self) -> Option<Chunk<'a>> {
8302        if self.range.start >= self.range.end {
8303            return None;
8304        }
8305        if self.range.start == self.diff_transforms.end().0 {
8306            self.diff_transforms.next();
8307        }
8308
8309        let diff_transform_start = self.diff_transforms.start().0;
8310        let diff_transform_end = self.diff_transforms.end().0;
8311        debug_assert!(
8312            self.range.start < diff_transform_end,
8313            "{:?} < {:?} of ({1:?}..{2:?})",
8314            self.range.start,
8315            diff_transform_end,
8316            diff_transform_start
8317        );
8318
8319        let diff_transform = self.diff_transforms.item()?;
8320        match diff_transform {
8321            DiffTransform::BufferContent { .. } => {
8322                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8323                    chunk
8324                } else {
8325                    let chunk = self.next_excerpt_chunk().unwrap();
8326                    self.buffer_chunk.insert(chunk)
8327                };
8328
8329                let chunk_end = self.range.start + chunk.text.len();
8330                let diff_transform_end = diff_transform_end.min(self.range.end);
8331
8332                if diff_transform_end < chunk_end {
8333                    let split_idx = diff_transform_end - self.range.start;
8334                    let (before, after) = chunk.text.split_at(split_idx);
8335                    self.range.start = diff_transform_end;
8336                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8337                    let chars = chunk.chars & mask;
8338                    let tabs = chunk.tabs & mask;
8339
8340                    chunk.text = after;
8341                    chunk.chars = chunk.chars >> split_idx;
8342                    chunk.tabs = chunk.tabs >> split_idx;
8343
8344                    Some(Chunk {
8345                        text: before,
8346                        chars,
8347                        tabs,
8348                        ..chunk.clone()
8349                    })
8350                } else {
8351                    self.range.start = chunk_end;
8352                    self.buffer_chunk.take()
8353                }
8354            }
8355            DiffTransform::DeletedHunk {
8356                buffer_id,
8357                base_text_byte_range,
8358                has_trailing_newline,
8359                ..
8360            } => {
8361                let base_text_start =
8362                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8363                let base_text_end =
8364                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8365                let base_text_end = base_text_end.min(base_text_byte_range.end);
8366
8367                let mut chunks = if let Some((_, mut chunks)) = self
8368                    .diff_base_chunks
8369                    .take()
8370                    .filter(|(id, _)| id == buffer_id)
8371                {
8372                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8373                    {
8374                        chunks.seek(base_text_start..base_text_end);
8375                    }
8376                    chunks
8377                } else {
8378                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8379                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8380                };
8381
8382                let chunk = if let Some(chunk) = chunks.next() {
8383                    self.range.start += chunk.text.len();
8384                    self.diff_base_chunks = Some((*buffer_id, chunks));
8385                    chunk
8386                } else {
8387                    debug_assert!(has_trailing_newline);
8388                    self.range.start += "\n".len();
8389                    Chunk {
8390                        text: "\n",
8391                        chars: 1u128,
8392                        ..Default::default()
8393                    }
8394                };
8395                Some(chunk)
8396            }
8397        }
8398    }
8399}
8400
8401impl MultiBufferBytes<'_> {
8402    fn consume(&mut self, len: usize) {
8403        self.range.start += len;
8404        self.chunk = &self.chunk[len..];
8405
8406        if !self.range.is_empty() && self.chunk.is_empty() {
8407            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8408                self.chunk = chunk;
8409            } else if self.has_trailing_newline {
8410                self.has_trailing_newline = false;
8411                self.chunk = b"\n";
8412            } else {
8413                self.cursor.next();
8414                if let Some(region) = self.cursor.region() {
8415                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8416                        region.buffer_range.start
8417                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8418                                .min(region.buffer_range.end),
8419                    );
8420                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8421                    self.excerpt_bytes = Some(excerpt_bytes);
8422                    self.has_trailing_newline =
8423                        region.has_trailing_newline && self.range.end >= region.range.end;
8424                    if self.chunk.is_empty() && self.has_trailing_newline {
8425                        self.has_trailing_newline = false;
8426                        self.chunk = b"\n";
8427                    }
8428                }
8429            }
8430        }
8431    }
8432}
8433
8434impl<'a> Iterator for MultiBufferBytes<'a> {
8435    type Item = &'a [u8];
8436
8437    fn next(&mut self) -> Option<Self::Item> {
8438        let chunk = self.chunk;
8439        if chunk.is_empty() {
8440            None
8441        } else {
8442            self.consume(chunk.len());
8443            Some(chunk)
8444        }
8445    }
8446}
8447
8448impl io::Read for MultiBufferBytes<'_> {
8449    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8450        let len = cmp::min(buf.len(), self.chunk.len());
8451        buf[..len].copy_from_slice(&self.chunk[..len]);
8452        if len > 0 {
8453            self.consume(len);
8454        }
8455        Ok(len)
8456    }
8457}
8458
8459impl io::Read for ReversedMultiBufferBytes<'_> {
8460    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8461        let len = cmp::min(buf.len(), self.chunk.len());
8462        buf[..len].copy_from_slice(&self.chunk[..len]);
8463        buf[..len].reverse();
8464        if len > 0 {
8465            self.range.end -= len;
8466            self.chunk = &self.chunk[..self.chunk.len() - len];
8467            if !self.range.is_empty()
8468                && self.chunk.is_empty()
8469                && let Some(chunk) = self.chunks.next()
8470            {
8471                self.chunk = chunk.as_bytes();
8472            }
8473        }
8474        Ok(len)
8475    }
8476}
8477
8478impl<'a> Iterator for ExcerptChunks<'a> {
8479    type Item = Chunk<'a>;
8480
8481    fn next(&mut self) -> Option<Self::Item> {
8482        if let Some(chunk) = self.content_chunks.next() {
8483            return Some(chunk);
8484        }
8485
8486        if self.has_footer {
8487            let text = "\n";
8488            let chars = 0b1;
8489            self.has_footer = false;
8490            return Some(Chunk {
8491                text,
8492                chars,
8493                ..Default::default()
8494            });
8495        }
8496
8497        None
8498    }
8499}
8500
8501impl ToOffset for Point {
8502    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8503        snapshot.point_to_offset(*self)
8504    }
8505    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8506        snapshot.point_to_offset_utf16(*self)
8507    }
8508}
8509
8510impl ToOffset for MultiBufferOffset {
8511    #[track_caller]
8512    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8513        assert!(
8514            *self <= snapshot.len(),
8515            "offset {} is greater than the snapshot.len() {}",
8516            self.0,
8517            snapshot.len().0,
8518        );
8519        *self
8520    }
8521    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8522        snapshot.offset_to_offset_utf16(*self)
8523    }
8524}
8525
8526impl ToOffset for MultiBufferOffsetUtf16 {
8527    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8528        snapshot.offset_utf16_to_offset(*self)
8529    }
8530
8531    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8532        *self
8533    }
8534}
8535
8536impl ToOffset for PointUtf16 {
8537    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8538        snapshot.point_utf16_to_offset(*self)
8539    }
8540    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8541        snapshot.point_utf16_to_offset_utf16(*self)
8542    }
8543}
8544
8545impl ToPoint for MultiBufferOffset {
8546    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8547        snapshot.offset_to_point(*self)
8548    }
8549    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8550        snapshot.offset_to_point_utf16(*self)
8551    }
8552}
8553
8554impl ToPoint for Point {
8555    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8556        *self
8557    }
8558    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8559        snapshot.point_to_point_utf16(*self)
8560    }
8561}
8562
8563impl ToPoint for PointUtf16 {
8564    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8565        snapshot.point_utf16_to_point(*self)
8566    }
8567    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8568        *self
8569    }
8570}
8571
8572impl From<ExcerptId> for EntityId {
8573    fn from(id: ExcerptId) -> Self {
8574        EntityId::from(id.0 as u64)
8575    }
8576}
8577
8578#[cfg(debug_assertions)]
8579pub mod debug {
8580    use super::*;
8581
8582    pub trait ToMultiBufferDebugRanges {
8583        fn to_multi_buffer_debug_ranges(
8584            &self,
8585            snapshot: &MultiBufferSnapshot,
8586        ) -> Vec<Range<MultiBufferOffset>>;
8587    }
8588
8589    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8590        fn to_multi_buffer_debug_ranges(
8591            &self,
8592            snapshot: &MultiBufferSnapshot,
8593        ) -> Vec<Range<MultiBufferOffset>> {
8594            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8595        }
8596    }
8597
8598    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8599        fn to_multi_buffer_debug_ranges(
8600            &self,
8601            snapshot: &MultiBufferSnapshot,
8602        ) -> Vec<Range<MultiBufferOffset>> {
8603            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8604                .to_multi_buffer_debug_ranges(snapshot)
8605        }
8606    }
8607
8608    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8609        fn to_multi_buffer_debug_ranges(
8610            &self,
8611            snapshot: &MultiBufferSnapshot,
8612        ) -> Vec<Range<MultiBufferOffset>> {
8613            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8614        }
8615    }
8616
8617    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8618        fn to_multi_buffer_debug_ranges(
8619            &self,
8620            snapshot: &MultiBufferSnapshot,
8621        ) -> Vec<Range<MultiBufferOffset>> {
8622            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8623        }
8624    }
8625
8626    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8627        fn to_multi_buffer_debug_ranges(
8628            &self,
8629            snapshot: &MultiBufferSnapshot,
8630        ) -> Vec<Range<MultiBufferOffset>> {
8631            self.iter()
8632                .map(|item| {
8633                    let offset = item.to_offset(snapshot);
8634                    offset..offset
8635                })
8636                .collect()
8637        }
8638    }
8639
8640    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8641        fn to_multi_buffer_debug_ranges(
8642            &self,
8643            snapshot: &MultiBufferSnapshot,
8644        ) -> Vec<Range<MultiBufferOffset>> {
8645            self.iter()
8646                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8647                .collect()
8648        }
8649    }
8650}