multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunk,
  14    DiffHunkSecondaryStatus, DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58use ztracing::instrument;
  59
  60pub use self::path_key::{PathExcerptInsertResult, PathKey};
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 519    excerpts: Vec<Locator>,
 520    _subscriptions: [gpui::Subscription; 2],
 521}
 522
 523struct DiffState {
 524    diff: Entity<BufferDiff>,
 525    is_inverted: bool,
 526    _subscription: gpui::Subscription,
 527}
 528
 529impl DiffState {
 530    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 531        DiffStateSnapshot {
 532            diff: self.diff.read(cx).snapshot(cx),
 533            is_inverted: self.is_inverted,
 534        }
 535    }
 536}
 537
 538#[derive(Clone)]
 539struct DiffStateSnapshot {
 540    diff: BufferDiffSnapshot,
 541    is_inverted: bool,
 542}
 543
 544impl std::ops::Deref for DiffStateSnapshot {
 545    type Target = BufferDiffSnapshot;
 546
 547    fn deref(&self) -> &Self::Target {
 548        &self.diff
 549    }
 550}
 551
 552impl DiffState {
 553    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 554        DiffState {
 555            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 556                BufferDiffEvent::DiffChanged(DiffChanged {
 557                    changed_range,
 558                    base_text_changed_range: _,
 559                    extended_range,
 560                }) => {
 561                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 562                    let range = if use_extended {
 563                        extended_range.clone()
 564                    } else {
 565                        changed_range.clone()
 566                    };
 567                    if let Some(range) = range {
 568                        this.buffer_diff_changed(diff, range, cx)
 569                    }
 570                    cx.emit(Event::BufferDiffChanged);
 571                }
 572                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 573                _ => {}
 574            }),
 575            diff,
 576            is_inverted: false,
 577        }
 578    }
 579
 580    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 581        DiffState {
 582            _subscription: cx.subscribe(&diff, {
 583                move |this, diff, event, cx| match event {
 584                    BufferDiffEvent::DiffChanged(DiffChanged {
 585                        changed_range: _,
 586                        base_text_changed_range,
 587                        extended_range: _,
 588                    }) => {
 589                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 590                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 591                        }
 592                        cx.emit(Event::BufferDiffChanged);
 593                    }
 594                    BufferDiffEvent::LanguageChanged => {
 595                        this.inverted_buffer_diff_language_changed(diff, cx)
 596                    }
 597                    _ => {}
 598                }
 599            }),
 600            diff,
 601            is_inverted: true,
 602        }
 603    }
 604}
 605
 606/// The contents of a [`MultiBuffer`] at a single point in time.
 607#[derive(Clone, Default)]
 608pub struct MultiBufferSnapshot {
 609    excerpts: SumTree<Excerpt>,
 610    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 611    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 612    diff_transforms: SumTree<DiffTransform>,
 613    excerpt_ids: SumTree<ExcerptIdMapping>,
 614    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 615    non_text_state_update_count: usize,
 616    edit_count: usize,
 617    is_dirty: bool,
 618    has_deleted_file: bool,
 619    has_conflict: bool,
 620    has_inverted_diff: bool,
 621    singleton: bool,
 622    trailing_excerpt_update_count: usize,
 623    all_diff_hunks_expanded: bool,
 624    show_deleted_hunks: bool,
 625    use_extended_diff_range: bool,
 626    show_headers: bool,
 627}
 628
 629// follower: None
 630// - BufferContent(Some)
 631// - BufferContent(None)
 632// - DeletedHunk
 633//
 634// follower: Some
 635// - BufferContent(Some)
 636// - BufferContent(None)
 637
 638#[derive(Debug, Clone)]
 639enum DiffTransform {
 640    // RealText
 641    BufferContent {
 642        summary: MBTextSummary,
 643        // modified_hunk_info
 644        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 645    },
 646    // ExpandedHunkText
 647    DeletedHunk {
 648        summary: TextSummary,
 649        buffer_id: BufferId,
 650        hunk_info: DiffTransformHunkInfo,
 651        base_text_byte_range: Range<usize>,
 652        has_trailing_newline: bool,
 653    },
 654}
 655
 656#[derive(Clone, Copy, Debug)]
 657struct DiffTransformHunkInfo {
 658    excerpt_id: ExcerptId,
 659    hunk_start_anchor: text::Anchor,
 660    hunk_secondary_status: DiffHunkSecondaryStatus,
 661    is_logically_deleted: bool,
 662}
 663
 664impl Eq for DiffTransformHunkInfo {}
 665
 666impl PartialEq for DiffTransformHunkInfo {
 667    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 668        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 669    }
 670}
 671
 672impl std::hash::Hash for DiffTransformHunkInfo {
 673    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 674        self.excerpt_id.hash(state);
 675        self.hunk_start_anchor.hash(state);
 676    }
 677}
 678
 679#[derive(Clone)]
 680pub struct ExcerptInfo {
 681    pub id: ExcerptId,
 682    pub buffer: Arc<BufferSnapshot>,
 683    pub buffer_id: BufferId,
 684    pub range: ExcerptRange<text::Anchor>,
 685    pub end_row: MultiBufferRow,
 686}
 687
 688impl std::fmt::Debug for ExcerptInfo {
 689    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 690        f.debug_struct(type_name::<Self>())
 691            .field("id", &self.id)
 692            .field("buffer_id", &self.buffer_id)
 693            .field("path", &self.buffer.file().map(|f| f.path()))
 694            .field("range", &self.range)
 695            .finish()
 696    }
 697}
 698
 699/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 700#[derive(Debug)]
 701pub struct ExcerptBoundary {
 702    pub prev: Option<ExcerptInfo>,
 703    pub next: ExcerptInfo,
 704    /// The row in the `MultiBuffer` where the boundary is located
 705    pub row: MultiBufferRow,
 706}
 707
 708impl ExcerptBoundary {
 709    pub fn starts_new_buffer(&self) -> bool {
 710        match (self.prev.as_ref(), &self.next) {
 711            (None, _) => true,
 712            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 713        }
 714    }
 715}
 716
 717#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 718pub struct ExpandInfo {
 719    pub direction: ExpandExcerptDirection,
 720    pub excerpt_id: ExcerptId,
 721}
 722
 723#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 724pub struct RowInfo {
 725    pub buffer_id: Option<BufferId>,
 726    pub buffer_row: Option<u32>,
 727    pub multibuffer_row: Option<MultiBufferRow>,
 728    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 729    pub expand_info: Option<ExpandInfo>,
 730    pub wrapped_buffer_row: Option<u32>,
 731}
 732
 733/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 734#[derive(Clone)]
 735struct Excerpt {
 736    /// The unique identifier for this excerpt
 737    id: ExcerptId,
 738    /// The location of the excerpt in the [`MultiBuffer`]
 739    locator: Locator,
 740    /// The buffer being excerpted
 741    buffer_id: BufferId,
 742    /// A snapshot of the buffer being excerpted
 743    buffer: Arc<BufferSnapshot>,
 744    /// The range of the buffer to be shown in the excerpt
 745    range: ExcerptRange<text::Anchor>,
 746    /// The last row in the excerpted slice of the buffer
 747    max_buffer_row: BufferRow,
 748    /// A summary of the text in the excerpt
 749    text_summary: TextSummary,
 750    has_trailing_newline: bool,
 751}
 752
 753/// A public view into an `Excerpt` in a [`MultiBuffer`].
 754///
 755/// Contains methods for getting the [`Buffer`] of the excerpt,
 756/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 757#[derive(Clone)]
 758pub struct MultiBufferExcerpt<'a> {
 759    excerpt: &'a Excerpt,
 760    diff_transforms:
 761        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 762    /// The offset in the multibuffer considering diff transforms.
 763    offset: MultiBufferOffset,
 764    /// The offset in the multibuffer without diff transforms.
 765    excerpt_offset: ExcerptOffset,
 766    buffer_offset: BufferOffset,
 767}
 768
 769#[derive(Clone, Debug)]
 770struct ExcerptIdMapping {
 771    id: ExcerptId,
 772    locator: Locator,
 773}
 774
 775/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 776/// These ranges are relative to the buffer itself
 777#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 778pub struct ExcerptRange<T> {
 779    /// The full range of text to be shown in the excerpt.
 780    pub context: Range<T>,
 781    /// The primary range of text to be highlighted in the excerpt.
 782    /// In a multi-buffer search, this would be the text that matched the search
 783    pub primary: Range<T>,
 784}
 785
 786impl<T: Clone> ExcerptRange<T> {
 787    pub fn new(context: Range<T>) -> Self {
 788        Self {
 789            context: context.clone(),
 790            primary: context,
 791        }
 792    }
 793}
 794
 795#[derive(Clone, Debug, Default)]
 796pub struct ExcerptSummary {
 797    excerpt_id: ExcerptId,
 798    /// The location of the last [`Excerpt`] being summarized
 799    excerpt_locator: Locator,
 800    widest_line_number: u32,
 801    text: MBTextSummary,
 802    count: usize,
 803}
 804
 805#[derive(Debug, Clone)]
 806pub struct DiffTransformSummary {
 807    input: MBTextSummary,
 808    output: MBTextSummary,
 809}
 810
 811/// Summary of a string of text.
 812#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 813pub struct MBTextSummary {
 814    /// Length in bytes.
 815    pub len: MultiBufferOffset,
 816    /// Length in UTF-8.
 817    pub chars: usize,
 818    /// Length in UTF-16 code units
 819    pub len_utf16: OffsetUtf16,
 820    /// A point representing the number of lines and the length of the last line.
 821    ///
 822    /// In other words, it marks the point after the last byte in the text, (if
 823    /// EOF was a character, this would be its position).
 824    pub lines: Point,
 825    /// How many `char`s are in the first line
 826    pub first_line_chars: u32,
 827    /// How many `char`s are in the last line
 828    pub last_line_chars: u32,
 829    /// How many UTF-16 code units are in the last line
 830    pub last_line_len_utf16: u32,
 831    /// The row idx of the longest row
 832    pub longest_row: u32,
 833    /// How many `char`s are in the longest row
 834    pub longest_row_chars: u32,
 835}
 836
 837impl From<TextSummary> for MBTextSummary {
 838    fn from(summary: TextSummary) -> Self {
 839        MBTextSummary {
 840            len: MultiBufferOffset(summary.len),
 841            chars: summary.chars,
 842            len_utf16: summary.len_utf16,
 843            lines: summary.lines,
 844            first_line_chars: summary.first_line_chars,
 845            last_line_chars: summary.last_line_chars,
 846            last_line_len_utf16: summary.last_line_len_utf16,
 847            longest_row: summary.longest_row,
 848            longest_row_chars: summary.longest_row_chars,
 849        }
 850    }
 851}
 852
 853impl From<MBTextSummary> for TextSummary {
 854    fn from(summary: MBTextSummary) -> Self {
 855        TextSummary {
 856            len: summary.len.0,
 857            chars: summary.chars,
 858            len_utf16: summary.len_utf16,
 859            lines: summary.lines,
 860            first_line_chars: summary.first_line_chars,
 861            last_line_chars: summary.last_line_chars,
 862            last_line_len_utf16: summary.last_line_len_utf16,
 863            longest_row: summary.longest_row,
 864            longest_row_chars: summary.longest_row_chars,
 865        }
 866    }
 867}
 868
 869impl From<&str> for MBTextSummary {
 870    fn from(text: &str) -> Self {
 871        MBTextSummary::from(TextSummary::from(text))
 872    }
 873}
 874
 875impl MultiBufferDimension for MBTextSummary {
 876    type TextDimension = TextSummary;
 877
 878    fn from_summary(summary: &MBTextSummary) -> Self {
 879        *summary
 880    }
 881
 882    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 883        *self += *summary;
 884    }
 885
 886    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 887        *self += *summary;
 888    }
 889}
 890
 891impl AddAssign for MBTextSummary {
 892    fn add_assign(&mut self, other: MBTextSummary) {
 893        let joined_chars = self.last_line_chars + other.first_line_chars;
 894        if joined_chars > self.longest_row_chars {
 895            self.longest_row = self.lines.row;
 896            self.longest_row_chars = joined_chars;
 897        }
 898        if other.longest_row_chars > self.longest_row_chars {
 899            self.longest_row = self.lines.row + other.longest_row;
 900            self.longest_row_chars = other.longest_row_chars;
 901        }
 902
 903        if self.lines.row == 0 {
 904            self.first_line_chars += other.first_line_chars;
 905        }
 906
 907        if other.lines.row == 0 {
 908            self.last_line_chars += other.first_line_chars;
 909            self.last_line_len_utf16 += other.last_line_len_utf16;
 910        } else {
 911            self.last_line_chars = other.last_line_chars;
 912            self.last_line_len_utf16 = other.last_line_len_utf16;
 913        }
 914
 915        self.chars += other.chars;
 916        self.len += other.len;
 917        self.len_utf16 += other.len_utf16;
 918        self.lines += other.lines;
 919    }
 920}
 921
 922impl AddAssign<TextSummary> for MBTextSummary {
 923    fn add_assign(&mut self, other: TextSummary) {
 924        *self += MBTextSummary::from(other);
 925    }
 926}
 927
 928impl MBTextSummary {
 929    pub fn lines_utf16(&self) -> PointUtf16 {
 930        PointUtf16 {
 931            row: self.lines.row,
 932            column: self.last_line_len_utf16,
 933        }
 934    }
 935}
 936
 937impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 938where
 939    K: MultiBufferDimension,
 940    V: MultiBufferDimension,
 941{
 942    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 943
 944    fn from_summary(summary: &MBTextSummary) -> Self {
 945        Self {
 946            key: K::from_summary(summary),
 947            value: Some(V::from_summary(summary)),
 948        }
 949    }
 950
 951    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 952        self.key.add_text_dim(&summary.key);
 953        if let Some(value) = &mut self.value {
 954            if let Some(other_value) = summary.value.as_ref() {
 955                value.add_text_dim(other_value);
 956            }
 957        }
 958    }
 959
 960    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 961        self.key.add_mb_text_summary(summary);
 962        if let Some(value) = &mut self.value {
 963            value.add_mb_text_summary(summary);
 964        }
 965    }
 966}
 967
 968#[derive(Clone)]
 969pub struct MultiBufferRows<'a> {
 970    point: Point,
 971    is_empty: bool,
 972    is_singleton: bool,
 973    cursor: MultiBufferCursor<'a, Point, Point>,
 974}
 975
 976pub struct MultiBufferChunks<'a> {
 977    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 978    diff_transforms:
 979        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 980    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 981    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 982    buffer_chunk: Option<Chunk<'a>>,
 983    range: Range<MultiBufferOffset>,
 984    excerpt_offset_range: Range<ExcerptOffset>,
 985    excerpt_chunks: Option<ExcerptChunks<'a>>,
 986    language_aware: bool,
 987}
 988
 989pub struct ReversedMultiBufferChunks<'a> {
 990    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 991    current_chunks: Option<rope::Chunks<'a>>,
 992    start: MultiBufferOffset,
 993    offset: MultiBufferOffset,
 994}
 995
 996pub struct MultiBufferBytes<'a> {
 997    range: Range<MultiBufferOffset>,
 998    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 999    excerpt_bytes: Option<text::Bytes<'a>>,
1000    has_trailing_newline: bool,
1001    chunk: &'a [u8],
1002}
1003
1004pub struct ReversedMultiBufferBytes<'a> {
1005    range: Range<MultiBufferOffset>,
1006    chunks: ReversedMultiBufferChunks<'a>,
1007    chunk: &'a [u8],
1008}
1009
1010#[derive(Clone)]
1011struct DiffTransforms<MBD> {
1012    output_dimension: OutputDimension<MBD>,
1013    excerpt_dimension: ExcerptDimension<MBD>,
1014}
1015
1016impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1017    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1018        Self {
1019            output_dimension: OutputDimension::zero(cx),
1020            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1021                cx,
1022            ),
1023        }
1024    }
1025
1026    fn add_summary(
1027        &mut self,
1028        summary: &'a DiffTransformSummary,
1029        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1030    ) {
1031        self.output_dimension.add_summary(summary, cx);
1032        self.excerpt_dimension.add_summary(summary, cx);
1033    }
1034}
1035
1036#[derive(Clone)]
1037struct MultiBufferCursor<'a, MBD, BD> {
1038    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1039    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1040    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1041    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1042}
1043
1044#[derive(Clone)]
1045struct MultiBufferRegion<'a, MBD, BD> {
1046    buffer: &'a BufferSnapshot,
1047    is_main_buffer: bool,
1048    diff_hunk_status: Option<DiffHunkStatus>,
1049    excerpt: &'a Excerpt,
1050    buffer_range: Range<BD>,
1051    range: Range<MBD>,
1052    has_trailing_newline: bool,
1053}
1054
1055struct ExcerptChunks<'a> {
1056    excerpt_id: ExcerptId,
1057    content_chunks: BufferChunks<'a>,
1058    has_footer: bool,
1059}
1060
1061#[derive(Debug)]
1062struct BufferEdit {
1063    range: Range<BufferOffset>,
1064    new_text: Arc<str>,
1065    is_insertion: bool,
1066    original_indent_column: Option<u32>,
1067    excerpt_id: ExcerptId,
1068}
1069
1070#[derive(Clone, Copy, Debug, PartialEq)]
1071enum DiffChangeKind {
1072    BufferEdited,
1073    DiffUpdated { base_changed: bool },
1074    ExpandOrCollapseHunks { expand: bool },
1075}
1076
1077#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1078pub enum ExpandExcerptDirection {
1079    Up,
1080    Down,
1081    UpAndDown,
1082}
1083
1084impl ExpandExcerptDirection {
1085    pub fn should_expand_up(&self) -> bool {
1086        match self {
1087            ExpandExcerptDirection::Up => true,
1088            ExpandExcerptDirection::Down => false,
1089            ExpandExcerptDirection::UpAndDown => true,
1090        }
1091    }
1092
1093    pub fn should_expand_down(&self) -> bool {
1094        match self {
1095            ExpandExcerptDirection::Up => false,
1096            ExpandExcerptDirection::Down => true,
1097            ExpandExcerptDirection::UpAndDown => true,
1098        }
1099    }
1100}
1101
1102#[derive(Clone, Debug, PartialEq)]
1103pub struct IndentGuide {
1104    pub buffer_id: BufferId,
1105    pub start_row: MultiBufferRow,
1106    pub end_row: MultiBufferRow,
1107    pub depth: u32,
1108    pub tab_size: u32,
1109    pub settings: IndentGuideSettings,
1110}
1111
1112impl IndentGuide {
1113    pub fn indent_level(&self) -> u32 {
1114        self.depth * self.tab_size
1115    }
1116}
1117
1118impl MultiBuffer {
1119    pub fn new(capability: Capability) -> Self {
1120        Self::new_(
1121            capability,
1122            MultiBufferSnapshot {
1123                show_headers: true,
1124                show_deleted_hunks: true,
1125                ..MultiBufferSnapshot::default()
1126            },
1127        )
1128    }
1129
1130    pub fn without_headers(capability: Capability) -> Self {
1131        Self::new_(
1132            capability,
1133            MultiBufferSnapshot {
1134                show_deleted_hunks: true,
1135                ..MultiBufferSnapshot::default()
1136            },
1137        )
1138    }
1139
1140    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1141        let mut this = Self::new_(
1142            buffer.read(cx).capability(),
1143            MultiBufferSnapshot {
1144                singleton: true,
1145                show_deleted_hunks: true,
1146                ..MultiBufferSnapshot::default()
1147            },
1148        );
1149        this.singleton = true;
1150        let buffer_id = buffer.read(cx).remote_id();
1151        this.push_excerpts(
1152            buffer,
1153            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1154                buffer_id,
1155            ))],
1156            cx,
1157        );
1158        this
1159    }
1160
1161    #[inline]
1162    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1163        Self {
1164            snapshot: RefCell::new(snapshot),
1165            buffers: Default::default(),
1166            diffs: HashMap::default(),
1167            subscriptions: Topic::default(),
1168            singleton: false,
1169            capability,
1170            title: None,
1171            excerpts_by_path: Default::default(),
1172            paths_by_excerpt: Default::default(),
1173            buffer_changed_since_sync: Default::default(),
1174            history: History::default(),
1175        }
1176    }
1177
1178    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1179        let mut buffers = BTreeMap::default();
1180        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1181        for (buffer_id, buffer_state) in self.buffers.iter() {
1182            buffer_state.buffer.update(new_cx, |buffer, _| {
1183                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1184            });
1185            buffers.insert(
1186                *buffer_id,
1187                BufferState {
1188                    buffer: buffer_state.buffer.clone(),
1189                    last_version: buffer_state.last_version.clone(),
1190                    last_non_text_state_update_count: buffer_state
1191                        .last_non_text_state_update_count
1192                        .clone(),
1193                    excerpts: buffer_state.excerpts.clone(),
1194                    _subscriptions: [
1195                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1196                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1197                    ],
1198                },
1199            );
1200        }
1201        let mut diff_bases = HashMap::default();
1202        for (buffer_id, diff) in self.diffs.iter() {
1203            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1204        }
1205        Self {
1206            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1207            buffers,
1208            excerpts_by_path: Default::default(),
1209            paths_by_excerpt: Default::default(),
1210            diffs: diff_bases,
1211            subscriptions: Default::default(),
1212            singleton: self.singleton,
1213            capability: self.capability,
1214            history: self.history.clone(),
1215            title: self.title.clone(),
1216            buffer_changed_since_sync,
1217        }
1218    }
1219
1220    pub fn set_group_interval(&mut self, group_interval: Duration) {
1221        self.history.set_group_interval(group_interval);
1222    }
1223
1224    pub fn with_title(mut self, title: String) -> Self {
1225        self.title = Some(title);
1226        self
1227    }
1228
1229    pub fn read_only(&self) -> bool {
1230        !self.capability.editable()
1231    }
1232
1233    pub fn capability(&self) -> Capability {
1234        self.capability
1235    }
1236
1237    /// Returns an up-to-date snapshot of the MultiBuffer.
1238    #[ztracing::instrument(skip_all)]
1239    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1240        self.sync(cx);
1241        self.snapshot.borrow().clone()
1242    }
1243
1244    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1245        self.sync(cx);
1246        self.snapshot.borrow()
1247    }
1248
1249    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1250        if self.singleton {
1251            Some(self.buffers.values().next().unwrap().buffer.clone())
1252        } else {
1253            None
1254        }
1255    }
1256
1257    pub fn is_singleton(&self) -> bool {
1258        self.singleton
1259    }
1260
1261    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1262        self.subscriptions.subscribe()
1263    }
1264
1265    pub fn is_dirty(&self, cx: &App) -> bool {
1266        self.read(cx).is_dirty()
1267    }
1268
1269    pub fn has_deleted_file(&self, cx: &App) -> bool {
1270        self.read(cx).has_deleted_file()
1271    }
1272
1273    pub fn has_conflict(&self, cx: &App) -> bool {
1274        self.read(cx).has_conflict()
1275    }
1276
1277    // The `is_empty` signature doesn't match what clippy expects
1278    #[allow(clippy::len_without_is_empty)]
1279    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1280        self.read(cx).len()
1281    }
1282
1283    pub fn is_empty(&self) -> bool {
1284        self.buffers.is_empty()
1285    }
1286
1287    pub fn edit<I, S, T>(
1288        &mut self,
1289        edits: I,
1290        autoindent_mode: Option<AutoindentMode>,
1291        cx: &mut Context<Self>,
1292    ) where
1293        I: IntoIterator<Item = (Range<S>, T)>,
1294        S: ToOffset,
1295        T: Into<Arc<str>>,
1296    {
1297        self.edit_internal(edits, autoindent_mode, true, cx);
1298    }
1299
1300    pub fn edit_non_coalesce<I, S, T>(
1301        &mut self,
1302        edits: I,
1303        autoindent_mode: Option<AutoindentMode>,
1304        cx: &mut Context<Self>,
1305    ) where
1306        I: IntoIterator<Item = (Range<S>, T)>,
1307        S: ToOffset,
1308        T: Into<Arc<str>>,
1309    {
1310        self.edit_internal(edits, autoindent_mode, false, cx);
1311    }
1312
1313    fn edit_internal<I, S, T>(
1314        &mut self,
1315        edits: I,
1316        autoindent_mode: Option<AutoindentMode>,
1317        coalesce_adjacent: bool,
1318        cx: &mut Context<Self>,
1319    ) where
1320        I: IntoIterator<Item = (Range<S>, T)>,
1321        S: ToOffset,
1322        T: Into<Arc<str>>,
1323    {
1324        if self.read_only() || self.buffers.is_empty() {
1325            return;
1326        }
1327        self.sync_mut(cx);
1328        let edits = edits
1329            .into_iter()
1330            .map(|(range, new_text)| {
1331                let mut range = range.start.to_offset(self.snapshot.get_mut())
1332                    ..range.end.to_offset(self.snapshot.get_mut());
1333                if range.start > range.end {
1334                    mem::swap(&mut range.start, &mut range.end);
1335                }
1336                (range, new_text.into())
1337            })
1338            .collect::<Vec<_>>();
1339
1340        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1341
1342        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1343        fn edit_internal(
1344            this: &mut MultiBuffer,
1345            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1346            mut autoindent_mode: Option<AutoindentMode>,
1347            coalesce_adjacent: bool,
1348            cx: &mut Context<MultiBuffer>,
1349        ) {
1350            let original_indent_columns = match &mut autoindent_mode {
1351                Some(AutoindentMode::Block {
1352                    original_indent_columns,
1353                }) => mem::take(original_indent_columns),
1354                _ => Default::default(),
1355            };
1356
1357            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1358                edits,
1359                this.snapshot.get_mut(),
1360                &original_indent_columns,
1361            );
1362
1363            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1364            for (buffer_id, mut edits) in buffer_edits {
1365                buffer_ids.push(buffer_id);
1366                edits.sort_by_key(|edit| edit.range.start);
1367                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1368                    let mut edits = edits.into_iter().peekable();
1369                    let mut insertions = Vec::new();
1370                    let mut original_indent_columns = Vec::new();
1371                    let mut deletions = Vec::new();
1372                    let empty_str: Arc<str> = Arc::default();
1373                    while let Some(BufferEdit {
1374                        mut range,
1375                        mut new_text,
1376                        mut is_insertion,
1377                        original_indent_column,
1378                        excerpt_id,
1379                    }) = edits.next()
1380                    {
1381                        while let Some(BufferEdit {
1382                            range: next_range,
1383                            is_insertion: next_is_insertion,
1384                            new_text: next_new_text,
1385                            excerpt_id: next_excerpt_id,
1386                            ..
1387                        }) = edits.peek()
1388                        {
1389                            let should_coalesce = if coalesce_adjacent {
1390                                range.end >= next_range.start
1391                            } else {
1392                                range.end > next_range.start
1393                            };
1394
1395                            if should_coalesce {
1396                                range.end = cmp::max(next_range.end, range.end);
1397                                is_insertion |= *next_is_insertion;
1398                                if excerpt_id == *next_excerpt_id {
1399                                    new_text = format!("{new_text}{next_new_text}").into();
1400                                }
1401                                edits.next();
1402                            } else {
1403                                break;
1404                            }
1405                        }
1406
1407                        if is_insertion {
1408                            original_indent_columns.push(original_indent_column);
1409                            insertions.push((
1410                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1411                                new_text.clone(),
1412                            ));
1413                        } else if !range.is_empty() {
1414                            deletions.push((
1415                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1416                                empty_str.clone(),
1417                            ));
1418                        }
1419                    }
1420
1421                    let deletion_autoindent_mode =
1422                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1423                            Some(AutoindentMode::Block {
1424                                original_indent_columns: Default::default(),
1425                            })
1426                        } else {
1427                            autoindent_mode.clone()
1428                        };
1429                    let insertion_autoindent_mode =
1430                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1431                            Some(AutoindentMode::Block {
1432                                original_indent_columns,
1433                            })
1434                        } else {
1435                            autoindent_mode.clone()
1436                        };
1437
1438                    if coalesce_adjacent {
1439                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1440                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1441                    } else {
1442                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1443                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1444                    }
1445                })
1446            }
1447
1448            cx.emit(Event::ExcerptsEdited {
1449                excerpt_ids: edited_excerpt_ids,
1450                buffer_ids,
1451            });
1452        }
1453    }
1454
1455    fn convert_edits_to_buffer_edits(
1456        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1457        snapshot: &MultiBufferSnapshot,
1458        original_indent_columns: &[Option<u32>],
1459    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1460        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1461        let mut edited_excerpt_ids = Vec::new();
1462        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1463        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1464            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1465
1466            cursor.seek(&range.start);
1467            let mut start_region = cursor.region().expect("start offset out of bounds");
1468            if !start_region.is_main_buffer {
1469                cursor.next();
1470                if let Some(region) = cursor.region() {
1471                    start_region = region;
1472                } else {
1473                    continue;
1474                }
1475            }
1476
1477            if range.end < start_region.range.start {
1478                continue;
1479            }
1480
1481            let start_region = start_region.clone();
1482            if range.end > start_region.range.end {
1483                cursor.seek_forward(&range.end);
1484            }
1485            let mut end_region = cursor.region().expect("end offset out of bounds");
1486            if !end_region.is_main_buffer {
1487                cursor.prev();
1488                if let Some(region) = cursor.region() {
1489                    end_region = region;
1490                } else {
1491                    continue;
1492                }
1493            }
1494
1495            if range.start > end_region.range.end {
1496                continue;
1497            }
1498
1499            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1500            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1501            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1502                .min(start_region.buffer_range.end);
1503            let buffer_end =
1504                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1505
1506            if start_region.excerpt.id == end_region.excerpt.id {
1507                if start_region.buffer.capability == Capability::ReadWrite
1508                    && start_region.is_main_buffer
1509                {
1510                    edited_excerpt_ids.push(start_region.excerpt.id);
1511                    buffer_edits
1512                        .entry(start_region.buffer.remote_id())
1513                        .or_default()
1514                        .push(BufferEdit {
1515                            range: buffer_start..buffer_end,
1516                            new_text,
1517                            is_insertion: true,
1518                            original_indent_column,
1519                            excerpt_id: start_region.excerpt.id,
1520                        });
1521                }
1522            } else {
1523                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1524                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1525                if start_region.buffer.capability == Capability::ReadWrite
1526                    && start_region.is_main_buffer
1527                {
1528                    edited_excerpt_ids.push(start_region.excerpt.id);
1529                    buffer_edits
1530                        .entry(start_region.buffer.remote_id())
1531                        .or_default()
1532                        .push(BufferEdit {
1533                            range: start_excerpt_range,
1534                            new_text: new_text.clone(),
1535                            is_insertion: true,
1536                            original_indent_column,
1537                            excerpt_id: start_region.excerpt.id,
1538                        });
1539                }
1540                let excerpt_id = end_region.excerpt.id;
1541                if end_region.buffer.capability == Capability::ReadWrite
1542                    && end_region.is_main_buffer
1543                {
1544                    edited_excerpt_ids.push(excerpt_id);
1545                    buffer_edits
1546                        .entry(end_region.buffer.remote_id())
1547                        .or_default()
1548                        .push(BufferEdit {
1549                            range: end_excerpt_range,
1550                            new_text: new_text.clone(),
1551                            is_insertion: false,
1552                            original_indent_column,
1553                            excerpt_id,
1554                        });
1555                }
1556
1557                cursor.seek(&range.start);
1558                cursor.next_excerpt();
1559                while let Some(region) = cursor.region() {
1560                    if region.excerpt.id == excerpt_id {
1561                        break;
1562                    }
1563                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1564                        edited_excerpt_ids.push(region.excerpt.id);
1565                        buffer_edits
1566                            .entry(region.buffer.remote_id())
1567                            .or_default()
1568                            .push(BufferEdit {
1569                                range: region.buffer_range.clone(),
1570                                new_text: new_text.clone(),
1571                                is_insertion: false,
1572                                original_indent_column,
1573                                excerpt_id: region.excerpt.id,
1574                            });
1575                    }
1576                    cursor.next_excerpt();
1577                }
1578            }
1579        }
1580        (buffer_edits, edited_excerpt_ids)
1581    }
1582
1583    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1584    where
1585        I: IntoIterator<Item = Range<S>>,
1586        S: ToOffset,
1587    {
1588        if self.read_only() || self.buffers.is_empty() {
1589            return;
1590        }
1591        self.sync_mut(cx);
1592        let empty = Arc::<str>::from("");
1593        let edits = ranges
1594            .into_iter()
1595            .map(|range| {
1596                let mut range = range.start.to_offset(self.snapshot.get_mut())
1597                    ..range.end.to_offset(&self.snapshot.get_mut());
1598                if range.start > range.end {
1599                    mem::swap(&mut range.start, &mut range.end);
1600                }
1601                (range, empty.clone())
1602            })
1603            .collect::<Vec<_>>();
1604
1605        return autoindent_ranges_internal(self, edits, cx);
1606
1607        fn autoindent_ranges_internal(
1608            this: &mut MultiBuffer,
1609            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1610            cx: &mut Context<MultiBuffer>,
1611        ) {
1612            let (buffer_edits, edited_excerpt_ids) =
1613                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1614
1615            let mut buffer_ids = Vec::new();
1616            for (buffer_id, mut edits) in buffer_edits {
1617                buffer_ids.push(buffer_id);
1618                edits.sort_unstable_by_key(|edit| edit.range.start);
1619
1620                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1621                for edit in edits {
1622                    if let Some(last_range) = ranges.last_mut()
1623                        && edit.range.start <= last_range.end
1624                    {
1625                        last_range.end = last_range.end.max(edit.range.end);
1626                        continue;
1627                    }
1628                    ranges.push(edit.range);
1629                }
1630
1631                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1632                    buffer.autoindent_ranges(ranges, cx);
1633                })
1634            }
1635
1636            cx.emit(Event::ExcerptsEdited {
1637                excerpt_ids: edited_excerpt_ids,
1638                buffer_ids,
1639            });
1640        }
1641    }
1642
1643    pub fn set_active_selections(
1644        &self,
1645        selections: &[Selection<Anchor>],
1646        line_mode: bool,
1647        cursor_shape: CursorShape,
1648        cx: &mut Context<Self>,
1649    ) {
1650        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1651            Default::default();
1652        let snapshot = self.read(cx);
1653        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1654        for selection in selections {
1655            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1656            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1657
1658            cursor.seek(&Some(start_locator), Bias::Left);
1659            while let Some(excerpt) = cursor.item()
1660                && excerpt.locator <= *end_locator
1661            {
1662                let mut start = excerpt.range.context.start;
1663                let mut end = excerpt.range.context.end;
1664                if excerpt.id == selection.start.excerpt_id {
1665                    start = selection.start.text_anchor;
1666                }
1667                if excerpt.id == selection.end.excerpt_id {
1668                    end = selection.end.text_anchor;
1669                }
1670                selections_by_buffer
1671                    .entry(excerpt.buffer_id)
1672                    .or_default()
1673                    .push(Selection {
1674                        id: selection.id,
1675                        start,
1676                        end,
1677                        reversed: selection.reversed,
1678                        goal: selection.goal,
1679                    });
1680
1681                cursor.next();
1682            }
1683        }
1684
1685        for (buffer_id, buffer_state) in self.buffers.iter() {
1686            if !selections_by_buffer.contains_key(buffer_id) {
1687                buffer_state
1688                    .buffer
1689                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1690            }
1691        }
1692
1693        for (buffer_id, mut selections) in selections_by_buffer {
1694            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1695                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1696                let mut selections = selections.into_iter().peekable();
1697                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1698                    let mut selection = selections.next()?;
1699                    while let Some(next_selection) = selections.peek() {
1700                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1701                            let next_selection = selections.next().unwrap();
1702                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1703                                selection.end = next_selection.end;
1704                            }
1705                        } else {
1706                            break;
1707                        }
1708                    }
1709                    Some(selection)
1710                }));
1711                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1712            });
1713        }
1714    }
1715
1716    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1717        for buffer in self.buffers.values() {
1718            buffer
1719                .buffer
1720                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1721        }
1722    }
1723
1724    pub fn push_excerpts<O>(
1725        &mut self,
1726        buffer: Entity<Buffer>,
1727        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1728        cx: &mut Context<Self>,
1729    ) -> Vec<ExcerptId>
1730    where
1731        O: text::ToOffset,
1732    {
1733        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1734    }
1735
1736    #[instrument(skip_all)]
1737    fn merge_excerpt_ranges<'a>(
1738        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1739    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1740        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1741        let mut counts: Vec<usize> = Vec::new();
1742        for range in expanded_ranges {
1743            if let Some(last_range) = merged_ranges.last_mut() {
1744                assert!(
1745                    last_range.context.start <= range.context.start,
1746                    "ranges must be sorted: {last_range:?} <= {range:?}"
1747                );
1748                if last_range.context.end >= range.context.start
1749                    || last_range.context.end.row + 1 == range.context.start.row
1750                {
1751                    last_range.context.end = range.context.end.max(last_range.context.end);
1752                    *counts.last_mut().unwrap() += 1;
1753                    continue;
1754                }
1755            }
1756            merged_ranges.push(range.clone());
1757            counts.push(1);
1758        }
1759        (merged_ranges, counts)
1760    }
1761
1762    pub fn insert_excerpts_after<O>(
1763        &mut self,
1764        prev_excerpt_id: ExcerptId,
1765        buffer: Entity<Buffer>,
1766        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1767        cx: &mut Context<Self>,
1768    ) -> Vec<ExcerptId>
1769    where
1770        O: text::ToOffset,
1771    {
1772        let mut ids = Vec::new();
1773        let mut next_excerpt_id =
1774            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1775                last_entry.id.0 + 1
1776            } else {
1777                1
1778            };
1779        self.insert_excerpts_with_ids_after(
1780            prev_excerpt_id,
1781            buffer,
1782            ranges.into_iter().map(|range| {
1783                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1784                ids.push(id);
1785                (id, range)
1786            }),
1787            cx,
1788        );
1789        ids
1790    }
1791
1792    pub fn insert_excerpts_with_ids_after<O>(
1793        &mut self,
1794        prev_excerpt_id: ExcerptId,
1795        buffer: Entity<Buffer>,
1796        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1797        cx: &mut Context<Self>,
1798    ) where
1799        O: text::ToOffset,
1800    {
1801        assert_eq!(self.history.transaction_depth(), 0);
1802        let mut ranges = ranges.into_iter().peekable();
1803        if ranges.peek().is_none() {
1804            return Default::default();
1805        }
1806
1807        self.sync_mut(cx);
1808
1809        let buffer_snapshot = buffer.read(cx).snapshot();
1810        let buffer_id = buffer_snapshot.remote_id();
1811
1812        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1813            self.buffer_changed_since_sync.replace(true);
1814            buffer.update(cx, |buffer, _| {
1815                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1816            });
1817            BufferState {
1818                last_version: RefCell::new(buffer_snapshot.version().clone()),
1819                last_non_text_state_update_count: Cell::new(
1820                    buffer_snapshot.non_text_state_update_count(),
1821                ),
1822                excerpts: Default::default(),
1823                _subscriptions: [
1824                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1825                    cx.subscribe(&buffer, Self::on_buffer_event),
1826                ],
1827                buffer: buffer.clone(),
1828            }
1829        });
1830
1831        let mut snapshot = self.snapshot.get_mut();
1832
1833        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1834        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1835        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1836        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1837        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1838
1839        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1840        new_excerpts.update_last(
1841            |excerpt| {
1842                excerpt.has_trailing_newline = true;
1843            },
1844            (),
1845        );
1846
1847        let next_locator = if let Some(excerpt) = cursor.item() {
1848            excerpt.locator.clone()
1849        } else {
1850            Locator::max()
1851        };
1852
1853        let mut excerpts = Vec::new();
1854        let buffer_snapshot = Arc::new(buffer_snapshot);
1855        while let Some((id, range)) = ranges.next() {
1856            let locator = Locator::between(&prev_locator, &next_locator);
1857            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1858                buffer_state.excerpts.insert(ix, locator.clone());
1859            }
1860            let range = ExcerptRange {
1861                context: buffer_snapshot.anchor_before(&range.context.start)
1862                    ..buffer_snapshot.anchor_after(&range.context.end),
1863                primary: buffer_snapshot.anchor_before(&range.primary.start)
1864                    ..buffer_snapshot.anchor_after(&range.primary.end),
1865            };
1866            excerpts.push((id, range.clone()));
1867            let excerpt = Excerpt::new(
1868                id,
1869                locator.clone(),
1870                buffer_id,
1871                buffer_snapshot.clone(),
1872                range,
1873                ranges.peek().is_some() || cursor.item().is_some(),
1874            );
1875            new_excerpts.push(excerpt, ());
1876            prev_locator = locator.clone();
1877
1878            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1879                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1880            }
1881            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1882        }
1883        snapshot
1884            .buffer_locators
1885            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1886
1887        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1888
1889        let suffix = cursor.suffix();
1890        let changed_trailing_excerpt = suffix.is_empty();
1891        new_excerpts.append(suffix, ());
1892        drop(cursor);
1893        snapshot.excerpts = new_excerpts;
1894        snapshot.excerpt_ids = new_excerpt_ids;
1895        if changed_trailing_excerpt {
1896            snapshot.trailing_excerpt_update_count += 1;
1897        }
1898
1899        let edits = Self::sync_diff_transforms(
1900            &mut snapshot,
1901            vec![Edit {
1902                old: edit_start..edit_start,
1903                new: edit_start..edit_end,
1904            }],
1905            DiffChangeKind::BufferEdited,
1906        );
1907        if !edits.is_empty() {
1908            self.subscriptions.publish(edits);
1909        }
1910
1911        cx.emit(Event::Edited {
1912            edited_buffer: None,
1913        });
1914        cx.emit(Event::ExcerptsAdded {
1915            buffer,
1916            predecessor: prev_excerpt_id,
1917            excerpts,
1918        });
1919        cx.notify();
1920    }
1921
1922    pub fn clear(&mut self, cx: &mut Context<Self>) {
1923        self.sync_mut(cx);
1924        let ids = self.excerpt_ids();
1925        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1926        self.excerpts_by_path.clear();
1927        self.paths_by_excerpt.clear();
1928        let MultiBufferSnapshot {
1929            excerpts,
1930            buffer_locators,
1931            diffs: _,
1932            diff_transforms: _,
1933            non_text_state_update_count: _,
1934            edit_count: _,
1935            is_dirty,
1936            has_deleted_file,
1937            has_conflict,
1938            has_inverted_diff,
1939            singleton: _,
1940            excerpt_ids: _,
1941            replaced_excerpts,
1942            trailing_excerpt_update_count,
1943            all_diff_hunks_expanded: _,
1944            show_deleted_hunks: _,
1945            use_extended_diff_range: _,
1946            show_headers: _,
1947        } = self.snapshot.get_mut();
1948        buffer_locators.clear();
1949        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1950        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1951        *excerpts = Default::default();
1952        *trailing_excerpt_update_count += 1;
1953        *is_dirty = false;
1954        *has_deleted_file = false;
1955        *has_conflict = false;
1956        *has_inverted_diff = false;
1957        replaced_excerpts.clear();
1958
1959        let edits = Self::sync_diff_transforms(
1960            self.snapshot.get_mut(),
1961            vec![Edit {
1962                old: start..prev_len,
1963                new: start..start,
1964            }],
1965            DiffChangeKind::BufferEdited,
1966        );
1967        if !edits.is_empty() {
1968            self.subscriptions.publish(edits);
1969        }
1970        cx.emit(Event::Edited {
1971            edited_buffer: None,
1972        });
1973        cx.emit(Event::ExcerptsRemoved {
1974            ids,
1975            removed_buffer_ids,
1976        });
1977        cx.notify();
1978    }
1979
1980    #[ztracing::instrument(skip_all)]
1981    pub fn excerpts_for_buffer(
1982        &self,
1983        buffer_id: BufferId,
1984        cx: &App,
1985    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1986        let mut excerpts = Vec::new();
1987        let snapshot = self.read(cx);
1988        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1989        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1990            for locator in &**locators {
1991                cursor.seek_forward(&Some(locator), Bias::Left);
1992                if let Some(excerpt) = cursor.item()
1993                    && excerpt.locator == *locator
1994                {
1995                    excerpts.push((excerpt.id, excerpt.range.clone()));
1996                }
1997            }
1998        }
1999
2000        excerpts
2001    }
2002
2003    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2004        let snapshot = self.read(cx);
2005        let mut excerpts = snapshot
2006            .excerpts
2007            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2008        let mut diff_transforms = snapshot
2009            .diff_transforms
2010            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2011        diff_transforms.next();
2012        let locators = snapshot
2013            .buffer_locators
2014            .get(&buffer_id)
2015            .into_iter()
2016            .flat_map(|v| &**v);
2017        let mut result = Vec::new();
2018        for locator in locators {
2019            excerpts.seek_forward(&Some(locator), Bias::Left);
2020            if let Some(excerpt) = excerpts.item()
2021                && excerpt.locator == *locator
2022            {
2023                let excerpt_start = excerpts.start().1;
2024                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2025
2026                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2027                let overshoot = excerpt_start - diff_transforms.start().0;
2028                let start = diff_transforms.start().1 + overshoot;
2029
2030                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2031                let overshoot = excerpt_end - diff_transforms.start().0;
2032                let end = diff_transforms.start().1 + overshoot;
2033
2034                result.push(start.0..end.0)
2035            }
2036        }
2037        result
2038    }
2039
2040    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2041        self.snapshot
2042            .borrow()
2043            .excerpts
2044            .iter()
2045            .map(|entry| entry.buffer_id)
2046            .collect()
2047    }
2048
2049    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2050        let snapshot = self.snapshot.borrow();
2051        let mut ids = Vec::with_capacity(snapshot.excerpts.summary().count);
2052        ids.extend(snapshot.excerpts.iter().map(|entry| entry.id));
2053        ids
2054    }
2055
2056    pub fn excerpt_containing(
2057        &self,
2058        position: impl ToOffset,
2059        cx: &App,
2060    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2061        let snapshot = self.read(cx);
2062        let offset = position.to_offset(&snapshot);
2063
2064        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2065        cursor.seek(&offset);
2066        cursor
2067            .excerpt()
2068            .or_else(|| snapshot.excerpts.last())
2069            .map(|excerpt| {
2070                (
2071                    excerpt.id,
2072                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2073                    excerpt.range.context.clone(),
2074                )
2075            })
2076    }
2077
2078    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2079        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2080            self.buffer(buffer_id)
2081        } else {
2082            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2083            Some(buffer)
2084        }
2085    }
2086
2087    // If point is at the end of the buffer, the last excerpt is returned
2088    pub fn point_to_buffer_offset<T: ToOffset>(
2089        &self,
2090        point: T,
2091        cx: &App,
2092    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2093        let snapshot = self.read(cx);
2094        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2095        Some((
2096            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2097            offset,
2098        ))
2099    }
2100
2101    // If point is at the end of the buffer, the last excerpt is returned
2102    pub fn point_to_buffer_point<T: ToPoint>(
2103        &self,
2104        point: T,
2105        cx: &App,
2106    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2107        let snapshot = self.read(cx);
2108        let (buffer, point, is_main_buffer) =
2109            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2110        Some((
2111            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2112            point,
2113            is_main_buffer,
2114        ))
2115    }
2116
2117    pub fn buffer_point_to_anchor(
2118        &self,
2119        // todo(lw): We shouldn't need this?
2120        buffer: &Entity<Buffer>,
2121        point: Point,
2122        cx: &App,
2123    ) -> Option<Anchor> {
2124        let mut found = None;
2125        let snapshot = buffer.read(cx).snapshot();
2126        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2127            let start = range.context.start.to_point(&snapshot);
2128            let end = range.context.end.to_point(&snapshot);
2129            if start <= point && point < end {
2130                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2131                break;
2132            }
2133            if point < start {
2134                found = Some((start, excerpt_id));
2135            }
2136            if point > end {
2137                found = Some((end, excerpt_id));
2138            }
2139        }
2140
2141        found.map(|(point, excerpt_id)| {
2142            let text_anchor = snapshot.anchor_after(point);
2143            Anchor::in_buffer(excerpt_id, text_anchor)
2144        })
2145    }
2146
2147    pub fn buffer_anchor_to_anchor(
2148        &self,
2149        // todo(lw): We shouldn't need this?
2150        buffer: &Entity<Buffer>,
2151        anchor: text::Anchor,
2152        cx: &App,
2153    ) -> Option<Anchor> {
2154        let snapshot = buffer.read(cx).snapshot();
2155        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2156            if range.context.start.cmp(&anchor, &snapshot).is_le()
2157                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2158            {
2159                return Some(Anchor::in_buffer(excerpt_id, anchor));
2160            }
2161        }
2162
2163        None
2164    }
2165
2166    pub fn merge_excerpts(
2167        &mut self,
2168        excerpt_ids: &[ExcerptId],
2169        cx: &mut Context<Self>,
2170    ) -> ExcerptId {
2171        debug_assert!(!excerpt_ids.is_empty());
2172        if excerpt_ids.len() == 1 {
2173            return excerpt_ids[0];
2174        }
2175
2176        let snapshot = self.snapshot(cx);
2177
2178        let first_range = snapshot
2179            .context_range_for_excerpt(excerpt_ids[0])
2180            .expect("first excerpt must exist");
2181        let last_range = snapshot
2182            .context_range_for_excerpt(*excerpt_ids.last().unwrap())
2183            .expect("last excerpt must exist");
2184
2185        let union_range = first_range.start..last_range.end;
2186
2187        drop(snapshot);
2188
2189        self.resize_excerpt(excerpt_ids[0], union_range, cx);
2190        self.remove_excerpts(excerpt_ids[1..].iter().copied(), cx);
2191
2192        excerpt_ids[0]
2193    }
2194
2195    pub fn remove_excerpts(
2196        &mut self,
2197        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2198        cx: &mut Context<Self>,
2199    ) {
2200        self.sync_mut(cx);
2201        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2202        if ids.is_empty() {
2203            return;
2204        }
2205        self.buffer_changed_since_sync.replace(true);
2206
2207        let mut snapshot = self.snapshot.get_mut();
2208        let mut new_excerpts = SumTree::default();
2209        let mut cursor = snapshot
2210            .excerpts
2211            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2212        let mut edits = Vec::new();
2213        let mut excerpt_ids = ids.iter().copied().peekable();
2214        let mut removed_buffer_ids = Vec::new();
2215        let mut removed_excerpts_for_buffers = HashSet::default();
2216
2217        while let Some(excerpt_id) = excerpt_ids.next() {
2218            self.paths_by_excerpt.remove(&excerpt_id);
2219            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2220            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2221            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2222
2223            if let Some(mut excerpt) = cursor.item() {
2224                if excerpt.id != excerpt_id {
2225                    continue;
2226                }
2227                let mut old_start = cursor.start().1;
2228
2229                // Skip over the removed excerpt.
2230                'remove_excerpts: loop {
2231                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2232                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2233                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2234                        if buffer_state.excerpts.is_empty() {
2235                            log::debug!(
2236                                "removing buffer and diff for buffer {}",
2237                                excerpt.buffer_id
2238                            );
2239                            self.buffers.remove(&excerpt.buffer_id);
2240                            removed_buffer_ids.push(excerpt.buffer_id);
2241                        }
2242                    }
2243                    cursor.next();
2244
2245                    // Skip over any subsequent excerpts that are also removed.
2246                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2247                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2248                        if let Some(next_excerpt) = cursor.item()
2249                            && next_excerpt.locator == *next_locator
2250                        {
2251                            excerpt_ids.next();
2252                            excerpt = next_excerpt;
2253                            continue 'remove_excerpts;
2254                        }
2255                    }
2256
2257                    break;
2258                }
2259
2260                // When removing the last excerpt, remove the trailing newline from
2261                // the previous excerpt.
2262                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2263                    old_start -= 1;
2264                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2265                }
2266
2267                // Push an edit for the removal of this run of excerpts.
2268                let old_end = cursor.start().1;
2269                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2270                edits.push(Edit {
2271                    old: old_start..old_end,
2272                    new: new_start..new_start,
2273                });
2274            }
2275        }
2276        let suffix = cursor.suffix();
2277        let changed_trailing_excerpt = suffix.is_empty();
2278        new_excerpts.append(suffix, ());
2279        drop(cursor);
2280        for buffer_id in removed_excerpts_for_buffers {
2281            match self.buffers.get(&buffer_id) {
2282                Some(buffer_state) => {
2283                    snapshot
2284                        .buffer_locators
2285                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2286                }
2287                None => {
2288                    snapshot.buffer_locators.remove(&buffer_id);
2289                }
2290            }
2291        }
2292        snapshot.excerpts = new_excerpts;
2293        for buffer_id in &removed_buffer_ids {
2294            self.diffs.remove(buffer_id);
2295            snapshot.diffs.remove(buffer_id);
2296        }
2297
2298        // Recalculate has_inverted_diff after removing diffs
2299        if !removed_buffer_ids.is_empty() {
2300            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2301        }
2302
2303        if changed_trailing_excerpt {
2304            snapshot.trailing_excerpt_update_count += 1;
2305        }
2306
2307        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2308        if !edits.is_empty() {
2309            self.subscriptions.publish(edits);
2310        }
2311        cx.emit(Event::Edited {
2312            edited_buffer: None,
2313        });
2314        cx.emit(Event::ExcerptsRemoved {
2315            ids,
2316            removed_buffer_ids,
2317        });
2318        cx.notify();
2319    }
2320
2321    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2322        &self,
2323        anchors: Anchors,
2324        cx: &mut Context<Self>,
2325    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2326        let mut error = None;
2327        let mut futures = Vec::new();
2328        for anchor in anchors {
2329            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2330                if let Some(buffer) = self.buffers.get(&buffer_id) {
2331                    buffer.buffer.update(cx, |buffer, _| {
2332                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2333                    });
2334                } else {
2335                    error = Some(anyhow!(
2336                        "buffer {buffer_id} is not part of this multi-buffer"
2337                    ));
2338                    break;
2339                }
2340            }
2341        }
2342        async move {
2343            if let Some(error) = error {
2344                Err(error)?;
2345            }
2346            for future in futures {
2347                future.await?;
2348            }
2349            Ok(())
2350        }
2351    }
2352
2353    pub fn text_anchor_for_position<T: ToOffset>(
2354        &self,
2355        position: T,
2356        cx: &App,
2357    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2358        let snapshot = self.read(cx);
2359        let anchor = snapshot.anchor_before(position);
2360        let buffer = self
2361            .buffers
2362            .get(&anchor.text_anchor.buffer_id?)?
2363            .buffer
2364            .clone();
2365        Some((buffer, anchor.text_anchor))
2366    }
2367
2368    fn on_buffer_event(
2369        &mut self,
2370        buffer: Entity<Buffer>,
2371        event: &language::BufferEvent,
2372        cx: &mut Context<Self>,
2373    ) {
2374        use language::BufferEvent;
2375        let buffer_id = buffer.read(cx).remote_id();
2376        cx.emit(match event {
2377            BufferEvent::Edited => Event::Edited {
2378                edited_buffer: Some(buffer),
2379            },
2380            BufferEvent::DirtyChanged => Event::DirtyChanged,
2381            BufferEvent::Saved => Event::Saved,
2382            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2383            BufferEvent::Reloaded => Event::Reloaded,
2384            BufferEvent::LanguageChanged(has_language) => {
2385                Event::LanguageChanged(buffer_id, *has_language)
2386            }
2387            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2388            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2389            BufferEvent::CapabilityChanged => {
2390                self.capability = buffer.read(cx).capability();
2391                return;
2392            }
2393            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2394        });
2395    }
2396
2397    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2398        let diff = diff.read(cx);
2399        let buffer_id = diff.buffer_id;
2400        let diff = DiffStateSnapshot {
2401            diff: diff.snapshot(cx),
2402            is_inverted: false,
2403        };
2404        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2405    }
2406
2407    fn inverted_buffer_diff_language_changed(
2408        &mut self,
2409        diff: Entity<BufferDiff>,
2410        cx: &mut Context<Self>,
2411    ) {
2412        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2413        let diff = diff.read(cx);
2414        let diff = DiffStateSnapshot {
2415            diff: diff.snapshot(cx),
2416            is_inverted: true,
2417        };
2418        self.snapshot
2419            .get_mut()
2420            .diffs
2421            .insert(base_text_buffer_id, diff);
2422    }
2423
2424    fn buffer_diff_changed(
2425        &mut self,
2426        diff: Entity<BufferDiff>,
2427        range: Range<text::Anchor>,
2428        cx: &mut Context<Self>,
2429    ) {
2430        self.sync_mut(cx);
2431
2432        let diff = diff.read(cx);
2433        let buffer_id = diff.buffer_id;
2434
2435        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2436            return;
2437        };
2438        let new_diff = DiffStateSnapshot {
2439            diff: diff.snapshot(cx),
2440            is_inverted: false,
2441        };
2442        let mut snapshot = self.snapshot.get_mut();
2443        let base_text_changed = snapshot
2444            .diffs
2445            .get(&buffer_id)
2446            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2447        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2448
2449        let buffer = buffer_state.buffer.read(cx);
2450        let diff_change_range = range.to_offset(buffer);
2451
2452        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2453        let edits = Self::sync_diff_transforms(
2454            &mut snapshot,
2455            excerpt_edits,
2456            DiffChangeKind::DiffUpdated {
2457                base_changed: base_text_changed,
2458            },
2459        );
2460        if !edits.is_empty() {
2461            self.subscriptions.publish(edits);
2462        }
2463        cx.emit(Event::Edited {
2464            edited_buffer: None,
2465        });
2466    }
2467
2468    fn inverted_buffer_diff_changed(
2469        &mut self,
2470        diff: Entity<BufferDiff>,
2471        diff_change_range: Range<usize>,
2472        cx: &mut Context<Self>,
2473    ) {
2474        self.sync_mut(cx);
2475
2476        let diff = diff.read(cx);
2477        let base_text_buffer_id = diff.base_text(cx).remote_id();
2478        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2479            return;
2480        };
2481
2482        let new_diff = DiffStateSnapshot {
2483            diff: diff.snapshot(cx),
2484            is_inverted: true,
2485        };
2486        let mut snapshot = self.snapshot.get_mut();
2487        snapshot
2488            .diffs
2489            .insert_or_replace(base_text_buffer_id, new_diff);
2490
2491        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2492        let edits = Self::sync_diff_transforms(
2493            &mut snapshot,
2494            excerpt_edits,
2495            DiffChangeKind::DiffUpdated {
2496                // We don't read this field for inverted diffs.
2497                base_changed: false,
2498            },
2499        );
2500        if !edits.is_empty() {
2501            self.subscriptions.publish(edits);
2502        }
2503        cx.emit(Event::Edited {
2504            edited_buffer: None,
2505        });
2506    }
2507
2508    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2509        self.buffers.values().map(|state| state.buffer.clone())
2510    }
2511
2512    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2513        self.all_buffers_iter().collect()
2514    }
2515
2516    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2517        self.buffers.keys().copied()
2518    }
2519
2520    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2521        self.all_buffer_ids_iter().collect()
2522    }
2523
2524    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2525        self.buffers
2526            .get(&buffer_id)
2527            .map(|state| state.buffer.clone())
2528    }
2529
2530    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2531        self.point_to_buffer_offset(point, cx)
2532            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2533    }
2534
2535    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2536        let buffer_id = self
2537            .snapshot
2538            .borrow()
2539            .excerpts
2540            .first()
2541            .map(|excerpt| excerpt.buffer.remote_id());
2542        buffer_id
2543            .and_then(|buffer_id| self.buffer(buffer_id))
2544            .map(|buffer| {
2545                let buffer = buffer.read(cx);
2546                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2547            })
2548            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2549    }
2550
2551    pub fn language_settings_at<'a, T: ToOffset>(
2552        &'a self,
2553        point: T,
2554        cx: &'a App,
2555    ) -> Cow<'a, LanguageSettings> {
2556        let mut language = None;
2557        let mut file = None;
2558        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2559            let buffer = buffer.read(cx);
2560            language = buffer.language_at(offset);
2561            file = buffer.file();
2562        }
2563        language_settings(language.map(|l| l.name()), file, cx)
2564    }
2565
2566    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2567        self.buffers.values().for_each(|state| f(&state.buffer))
2568    }
2569
2570    pub fn explicit_title(&self) -> Option<&str> {
2571        self.title.as_deref()
2572    }
2573
2574    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2575        if let Some(title) = self.title.as_ref() {
2576            return title.into();
2577        }
2578
2579        if let Some(buffer) = self.as_singleton() {
2580            let buffer = buffer.read(cx);
2581
2582            if let Some(file) = buffer.file() {
2583                return file.file_name(cx).into();
2584            }
2585
2586            if let Some(title) = self.buffer_content_title(buffer) {
2587                return title;
2588            }
2589        };
2590
2591        "untitled".into()
2592    }
2593
2594    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2595        let mut is_leading_whitespace = true;
2596        let mut count = 0;
2597        let mut prev_was_space = false;
2598        let mut title = String::new();
2599
2600        for ch in buffer.snapshot().chars() {
2601            if is_leading_whitespace && ch.is_whitespace() {
2602                continue;
2603            }
2604
2605            is_leading_whitespace = false;
2606
2607            if ch == '\n' || count >= 40 {
2608                break;
2609            }
2610
2611            if ch.is_whitespace() {
2612                if !prev_was_space {
2613                    title.push(' ');
2614                    count += 1;
2615                    prev_was_space = true;
2616                }
2617            } else {
2618                title.push(ch);
2619                count += 1;
2620                prev_was_space = false;
2621            }
2622        }
2623
2624        let title = title.trim_end().to_string();
2625
2626        if title.is_empty() {
2627            return None;
2628        }
2629
2630        Some(title.into())
2631    }
2632
2633    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2634        self.title = Some(title);
2635        cx.notify();
2636    }
2637
2638    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2639    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2640        for buffer_state in self.buffers.values() {
2641            buffer_state
2642                .buffer
2643                .update(cx, |buffer, _cx| buffer.refresh_preview());
2644        }
2645    }
2646
2647    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2648    pub fn preserve_preview(&self, cx: &App) -> bool {
2649        self.buffers
2650            .values()
2651            .all(|state| state.buffer.read(cx).preserve_preview())
2652    }
2653
2654    #[cfg(any(test, feature = "test-support"))]
2655    pub fn is_parsing(&self, cx: &App) -> bool {
2656        self.as_singleton().unwrap().read(cx).is_parsing()
2657    }
2658
2659    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2660        let buffer_id = diff.read(cx).buffer_id;
2661
2662        if let Some(existing_diff) = self.diff_for(buffer_id)
2663            && diff.entity_id() == existing_diff.entity_id()
2664        {
2665            return;
2666        }
2667
2668        self.buffer_diff_changed(
2669            diff.clone(),
2670            text::Anchor::min_max_range_for_buffer(buffer_id),
2671            cx,
2672        );
2673        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2674    }
2675
2676    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2677        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2678        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2679        self.snapshot.get_mut().has_inverted_diff = true;
2680        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2681        self.diffs
2682            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2683    }
2684
2685    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2686        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2687    }
2688
2689    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2690        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2691    }
2692
2693    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2694        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2695    }
2696
2697    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2698        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2699        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2700    }
2701
2702    pub fn all_diff_hunks_expanded(&self) -> bool {
2703        self.snapshot.borrow().all_diff_hunks_expanded
2704    }
2705
2706    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2707        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2708        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2709    }
2710
2711    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2712        self.snapshot.get_mut().show_deleted_hunks = show;
2713        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2714    }
2715
2716    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2717        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2718    }
2719
2720    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2721        self.read(cx)
2722            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2723            .nth(1)
2724            .is_some()
2725    }
2726
2727    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2728        let snapshot = self.read(cx);
2729        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2730        let offset_range = range.to_offset(&snapshot);
2731        cursor.seek(&offset_range.start, Bias::Left);
2732        while let Some(item) = cursor.item() {
2733            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2734                break;
2735            }
2736            if item.hunk_info().is_some() {
2737                return true;
2738            }
2739            cursor.next();
2740        }
2741        false
2742    }
2743
2744    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2745        let snapshot = self.read(cx);
2746        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2747        for range in ranges {
2748            let range = range.to_point(&snapshot);
2749            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2750            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2751                .min(snapshot.len());
2752            cursor.seek(&start, Bias::Right);
2753            while let Some(item) = cursor.item() {
2754                if *cursor.start() >= end {
2755                    break;
2756                }
2757                if item.hunk_info().is_some() {
2758                    return true;
2759                }
2760                cursor.next();
2761            }
2762        }
2763        false
2764    }
2765
2766    pub fn expand_or_collapse_diff_hunks_inner(
2767        &mut self,
2768        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2769        expand: bool,
2770        cx: &mut Context<Self>,
2771    ) {
2772        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2773            return;
2774        }
2775        self.sync_mut(cx);
2776        let mut snapshot = self.snapshot.get_mut();
2777        let mut excerpt_edits = Vec::new();
2778        let mut last_hunk_row = None;
2779        for (range, end_excerpt_id) in ranges {
2780            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2781                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2782                    continue;
2783                }
2784                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2785                    continue;
2786                }
2787                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2788                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2789                let start = snapshot.excerpt_offset_for_anchor(&start);
2790                let end = snapshot.excerpt_offset_for_anchor(&end);
2791                last_hunk_row = Some(diff_hunk.row_range.start);
2792                excerpt_edits.push(text::Edit {
2793                    old: start..end,
2794                    new: start..end,
2795                });
2796            }
2797        }
2798
2799        let edits = Self::sync_diff_transforms(
2800            &mut snapshot,
2801            excerpt_edits,
2802            DiffChangeKind::ExpandOrCollapseHunks { expand },
2803        );
2804        if !edits.is_empty() {
2805            self.subscriptions.publish(edits);
2806        }
2807        cx.emit(Event::DiffHunksToggled);
2808        cx.emit(Event::Edited {
2809            edited_buffer: None,
2810        });
2811    }
2812
2813    pub fn expand_or_collapse_diff_hunks(
2814        &mut self,
2815        ranges: Vec<Range<Anchor>>,
2816        expand: bool,
2817        cx: &mut Context<Self>,
2818    ) {
2819        let snapshot = self.snapshot.borrow().clone();
2820        let ranges = ranges.iter().map(move |range| {
2821            let end_excerpt_id = range.end.excerpt_id;
2822            let range = range.to_point(&snapshot);
2823            let mut peek_end = range.end;
2824            if range.end.row < snapshot.max_row().0 {
2825                peek_end = Point::new(range.end.row + 1, 0);
2826            };
2827            (range.start..peek_end, end_excerpt_id)
2828        });
2829        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2830    }
2831
2832    pub fn resize_excerpt(
2833        &mut self,
2834        id: ExcerptId,
2835        range: Range<text::Anchor>,
2836        cx: &mut Context<Self>,
2837    ) {
2838        self.sync_mut(cx);
2839
2840        let mut snapshot = self.snapshot.get_mut();
2841        let locator = snapshot.excerpt_locator_for_id(id);
2842        let mut new_excerpts = SumTree::default();
2843        let mut cursor = snapshot
2844            .excerpts
2845            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2846        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2847
2848        let prefix = cursor.slice(&Some(locator), Bias::Left);
2849        new_excerpts.append(prefix, ());
2850
2851        let mut excerpt = cursor.item().unwrap().clone();
2852        let old_text_len = excerpt.text_summary.len;
2853
2854        excerpt.range.context.start = range.start;
2855        excerpt.range.context.end = range.end;
2856        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2857
2858        excerpt.text_summary = excerpt
2859            .buffer
2860            .text_summary_for_range(excerpt.range.context.clone());
2861
2862        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2863        let old_start_offset = cursor.start().1;
2864        let new_text_len = excerpt.text_summary.len;
2865        let edit = Edit {
2866            old: old_start_offset..old_start_offset + old_text_len,
2867            new: new_start_offset..new_start_offset + new_text_len,
2868        };
2869
2870        if let Some(last_edit) = edits.last_mut() {
2871            if last_edit.old.end == edit.old.start {
2872                last_edit.old.end = edit.old.end;
2873                last_edit.new.end = edit.new.end;
2874            } else {
2875                edits.push(edit);
2876            }
2877        } else {
2878            edits.push(edit);
2879        }
2880
2881        new_excerpts.push(excerpt, ());
2882
2883        cursor.next();
2884
2885        new_excerpts.append(cursor.suffix(), ());
2886
2887        drop(cursor);
2888        snapshot.excerpts = new_excerpts;
2889
2890        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2891        if !edits.is_empty() {
2892            self.subscriptions.publish(edits);
2893        }
2894        cx.emit(Event::Edited {
2895            edited_buffer: None,
2896        });
2897        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2898        cx.notify();
2899    }
2900
2901    pub fn expand_excerpts(
2902        &mut self,
2903        ids: impl IntoIterator<Item = ExcerptId>,
2904        line_count: u32,
2905        direction: ExpandExcerptDirection,
2906        cx: &mut Context<Self>,
2907    ) {
2908        if line_count == 0 {
2909            return;
2910        }
2911        self.sync_mut(cx);
2912        if !self.excerpts_by_path.is_empty() {
2913            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2914            return;
2915        }
2916        let mut snapshot = self.snapshot.get_mut();
2917
2918        let ids = ids.into_iter().collect::<Vec<_>>();
2919        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2920        let mut new_excerpts = SumTree::default();
2921        let mut cursor = snapshot
2922            .excerpts
2923            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2924        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2925
2926        for locator in &locators {
2927            let prefix = cursor.slice(&Some(locator), Bias::Left);
2928            new_excerpts.append(prefix, ());
2929
2930            let mut excerpt = cursor.item().unwrap().clone();
2931            let old_text_len = excerpt.text_summary.len;
2932
2933            let up_line_count = if direction.should_expand_up() {
2934                line_count
2935            } else {
2936                0
2937            };
2938
2939            let start_row = excerpt
2940                .range
2941                .context
2942                .start
2943                .to_point(&excerpt.buffer)
2944                .row
2945                .saturating_sub(up_line_count);
2946            let start_point = Point::new(start_row, 0);
2947            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2948
2949            let down_line_count = if direction.should_expand_down() {
2950                line_count
2951            } else {
2952                0
2953            };
2954
2955            let mut end_point = excerpt.buffer.clip_point(
2956                excerpt.range.context.end.to_point(&excerpt.buffer)
2957                    + Point::new(down_line_count, 0),
2958                Bias::Left,
2959            );
2960            end_point.column = excerpt.buffer.line_len(end_point.row);
2961            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2962            excerpt.max_buffer_row = end_point.row;
2963
2964            excerpt.text_summary = excerpt
2965                .buffer
2966                .text_summary_for_range(excerpt.range.context.clone());
2967
2968            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2969            let old_start_offset = cursor.start().1;
2970            let new_text_len = excerpt.text_summary.len;
2971            let edit = Edit {
2972                old: old_start_offset..old_start_offset + old_text_len,
2973                new: new_start_offset..new_start_offset + new_text_len,
2974            };
2975
2976            if let Some(last_edit) = edits.last_mut() {
2977                if last_edit.old.end == edit.old.start {
2978                    last_edit.old.end = edit.old.end;
2979                    last_edit.new.end = edit.new.end;
2980                } else {
2981                    edits.push(edit);
2982                }
2983            } else {
2984                edits.push(edit);
2985            }
2986
2987            new_excerpts.push(excerpt, ());
2988
2989            cursor.next();
2990        }
2991
2992        new_excerpts.append(cursor.suffix(), ());
2993
2994        drop(cursor);
2995        snapshot.excerpts = new_excerpts;
2996
2997        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2998        if !edits.is_empty() {
2999            self.subscriptions.publish(edits);
3000        }
3001        cx.emit(Event::Edited {
3002            edited_buffer: None,
3003        });
3004        cx.emit(Event::ExcerptsExpanded { ids });
3005        cx.notify();
3006    }
3007
3008    #[ztracing::instrument(skip_all)]
3009    fn sync(&self, cx: &App) {
3010        let changed = self.buffer_changed_since_sync.replace(false);
3011        if !changed {
3012            return;
3013        }
3014        let edits = Self::sync_from_buffer_changes(
3015            &mut self.snapshot.borrow_mut(),
3016            &self.buffers,
3017            &self.diffs,
3018            cx,
3019        );
3020        if !edits.is_empty() {
3021            self.subscriptions.publish(edits);
3022        }
3023    }
3024
3025    fn sync_mut(&mut self, cx: &App) {
3026        let changed = self.buffer_changed_since_sync.replace(false);
3027        if !changed {
3028            return;
3029        }
3030        let edits =
3031            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3032
3033        if !edits.is_empty() {
3034            self.subscriptions.publish(edits);
3035        }
3036    }
3037
3038    fn sync_from_buffer_changes(
3039        snapshot: &mut MultiBufferSnapshot,
3040        buffers: &BTreeMap<BufferId, BufferState>,
3041        diffs: &HashMap<BufferId, DiffState>,
3042        cx: &App,
3043    ) -> Vec<Edit<MultiBufferOffset>> {
3044        let MultiBufferSnapshot {
3045            excerpts,
3046            buffer_locators: _,
3047            diffs: buffer_diff,
3048            diff_transforms: _,
3049            non_text_state_update_count,
3050            edit_count,
3051            is_dirty,
3052            has_deleted_file,
3053            has_conflict,
3054            has_inverted_diff: _,
3055            singleton: _,
3056            excerpt_ids: _,
3057            replaced_excerpts: _,
3058            trailing_excerpt_update_count: _,
3059            all_diff_hunks_expanded: _,
3060            show_deleted_hunks: _,
3061            use_extended_diff_range: _,
3062            show_headers: _,
3063        } = snapshot;
3064        *is_dirty = false;
3065        *has_deleted_file = false;
3066        *has_conflict = false;
3067
3068        if !diffs.is_empty() {
3069            let mut diffs_to_add = Vec::new();
3070            for (id, diff) in diffs {
3071                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3072                // and use the diff hunk base text ranges to compute diff transforms.
3073                // Those base text ranges are usize, so make sure if the base text changed
3074                // we also update the diff snapshot so that we don't use stale offsets
3075                if buffer_diff.get(id).is_none_or(|existing_diff| {
3076                    if !existing_diff.is_inverted {
3077                        return false;
3078                    }
3079                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3080                    base_text.remote_id() != existing_diff.base_text().remote_id()
3081                        || base_text
3082                            .version()
3083                            .changed_since(existing_diff.base_text().version())
3084                }) {
3085                    if diffs_to_add.capacity() == 0 {
3086                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3087                        // meaning re-allocations will be fairly expensive
3088                        diffs_to_add.reserve(diffs.len());
3089                    }
3090                    diffs_to_add.push((*id, diff.snapshot(cx)));
3091                }
3092            }
3093            buffer_diff.extend(diffs_to_add);
3094        }
3095
3096        let mut excerpts_to_edit = Vec::new();
3097        let mut non_text_state_updated = false;
3098        let mut edited = false;
3099        for buffer_state in buffers.values() {
3100            let buffer = buffer_state.buffer.read(cx);
3101            let version = buffer.version();
3102            let non_text_state_update_count = buffer.non_text_state_update_count();
3103
3104            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3105            let buffer_non_text_state_updated =
3106                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3107            if buffer_edited || buffer_non_text_state_updated {
3108                *buffer_state.last_version.borrow_mut() = version;
3109                buffer_state
3110                    .last_non_text_state_update_count
3111                    .set(non_text_state_update_count);
3112                excerpts_to_edit.extend(
3113                    buffer_state
3114                        .excerpts
3115                        .iter()
3116                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3117                );
3118            }
3119
3120            edited |= buffer_edited;
3121            non_text_state_updated |= buffer_non_text_state_updated;
3122            *is_dirty |= buffer.is_dirty();
3123            *has_deleted_file |= buffer
3124                .file()
3125                .is_some_and(|file| file.disk_state().is_deleted());
3126            *has_conflict |= buffer.has_conflict();
3127        }
3128        if edited {
3129            *edit_count += 1;
3130        }
3131        if non_text_state_updated {
3132            *non_text_state_update_count += 1;
3133        }
3134
3135        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3136
3137        let mut edits = Vec::new();
3138        let mut new_excerpts = SumTree::default();
3139        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3140
3141        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3142            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3143            let old_excerpt = cursor.item().unwrap();
3144            let buffer = buffer.read(cx);
3145            let buffer_id = buffer.remote_id();
3146            let mut new_excerpt;
3147            if buffer_edited {
3148                edits.extend(
3149                    buffer
3150                        .edits_since_in_range::<usize>(
3151                            old_excerpt.buffer.version(),
3152                            old_excerpt.range.context.clone(),
3153                        )
3154                        .map(|edit| {
3155                            let excerpt_old_start = cursor.start().1;
3156                            let excerpt_new_start =
3157                                ExcerptDimension(new_excerpts.summary().text.len);
3158                            let old_start = excerpt_old_start + edit.old.start;
3159                            let old_end = excerpt_old_start + edit.old.end;
3160                            let new_start = excerpt_new_start + edit.new.start;
3161                            let new_end = excerpt_new_start + edit.new.end;
3162                            Edit {
3163                                old: old_start..old_end,
3164                                new: new_start..new_end,
3165                            }
3166                        }),
3167                );
3168
3169                new_excerpt = Excerpt::new(
3170                    old_excerpt.id,
3171                    locator.clone(),
3172                    buffer_id,
3173                    Arc::new(buffer.snapshot()),
3174                    old_excerpt.range.clone(),
3175                    old_excerpt.has_trailing_newline,
3176                );
3177            } else {
3178                new_excerpt = old_excerpt.clone();
3179                new_excerpt.buffer = Arc::new(buffer.snapshot());
3180            }
3181
3182            new_excerpts.push(new_excerpt, ());
3183            cursor.next();
3184        }
3185        new_excerpts.append(cursor.suffix(), ());
3186
3187        drop(cursor);
3188        *excerpts = new_excerpts;
3189
3190        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3191    }
3192
3193    fn sync_diff_transforms(
3194        snapshot: &mut MultiBufferSnapshot,
3195        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3196        change_kind: DiffChangeKind,
3197    ) -> Vec<Edit<MultiBufferOffset>> {
3198        if excerpt_edits.is_empty() {
3199            return vec![];
3200        }
3201
3202        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3203        let mut old_diff_transforms = snapshot
3204            .diff_transforms
3205            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3206        let mut new_diff_transforms = SumTree::default();
3207        let mut old_expanded_hunks = HashSet::default();
3208        let mut output_edits = Vec::new();
3209        let mut output_delta = 0_isize;
3210        let mut at_transform_boundary = true;
3211        let mut end_of_current_insert = None;
3212
3213        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3214        while let Some(edit) = excerpt_edits.next() {
3215            excerpts.seek_forward(&edit.new.start, Bias::Right);
3216            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3217                excerpts.prev();
3218            }
3219
3220            // Keep any transforms that are before the edit.
3221            if at_transform_boundary {
3222                at_transform_boundary = false;
3223                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3224                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3225                if let Some(transform) = old_diff_transforms.item()
3226                    && old_diff_transforms.end().0 == edit.old.start
3227                    && old_diff_transforms.start().0 < edit.old.start
3228                {
3229                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3230                    old_diff_transforms.next();
3231                }
3232            }
3233
3234            // Compute the start of the edit in output coordinates.
3235            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3236            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3237            let edit_new_start =
3238                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3239
3240            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3241                &edit,
3242                &mut excerpts,
3243                &mut old_diff_transforms,
3244                &mut new_diff_transforms,
3245                &mut end_of_current_insert,
3246                &mut old_expanded_hunks,
3247                snapshot,
3248                change_kind,
3249            );
3250
3251            // Compute the end of the edit in output coordinates.
3252            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3253            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3254            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3255            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3256            let output_edit = Edit {
3257                old: edit_old_start..edit_old_end,
3258                new: edit_new_start..edit_new_end,
3259            };
3260
3261            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3262            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3263            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3264                output_edits.push(output_edit);
3265            }
3266
3267            // If this is the last edit that intersects the current diff transform,
3268            // then recreate the content up to the end of this transform, to prepare
3269            // for reusing additional slices of the old transforms.
3270            if excerpt_edits
3271                .peek()
3272                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3273            {
3274                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3275                    && match old_diff_transforms.item() {
3276                        Some(DiffTransform::BufferContent {
3277                            inserted_hunk_info: Some(hunk),
3278                            ..
3279                        }) => excerpts.item().is_some_and(|excerpt| {
3280                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3281                                && diff.is_inverted
3282                            {
3283                                return true;
3284                            }
3285                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3286                        }),
3287                        _ => true,
3288                    };
3289
3290                let mut excerpt_offset = edit.new.end;
3291                if !keep_next_old_transform {
3292                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3293                    old_diff_transforms.next();
3294                }
3295
3296                old_expanded_hunks.clear();
3297                Self::push_buffer_content_transform(
3298                    snapshot,
3299                    &mut new_diff_transforms,
3300                    excerpt_offset,
3301                    end_of_current_insert,
3302                );
3303                at_transform_boundary = true;
3304            }
3305        }
3306
3307        // Keep any transforms that are after the last edit.
3308        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3309
3310        // Ensure there's always at least one buffer content transform.
3311        if new_diff_transforms.is_empty() {
3312            new_diff_transforms.push(
3313                DiffTransform::BufferContent {
3314                    summary: Default::default(),
3315                    inserted_hunk_info: None,
3316                },
3317                (),
3318            );
3319        }
3320
3321        drop(old_diff_transforms);
3322        drop(excerpts);
3323        snapshot.diff_transforms = new_diff_transforms;
3324        snapshot.edit_count += 1;
3325
3326        #[cfg(any(test, feature = "test-support"))]
3327        snapshot.check_invariants();
3328        output_edits
3329    }
3330
3331    fn recompute_diff_transforms_for_edit(
3332        edit: &Edit<ExcerptOffset>,
3333        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3334        old_diff_transforms: &mut Cursor<
3335            DiffTransform,
3336            Dimensions<ExcerptOffset, MultiBufferOffset>,
3337        >,
3338        new_diff_transforms: &mut SumTree<DiffTransform>,
3339        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3340        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3341        snapshot: &MultiBufferSnapshot,
3342        change_kind: DiffChangeKind,
3343    ) -> bool {
3344        log::trace!(
3345            "recomputing diff transform for edit {:?} => {:?}",
3346            edit.old.start..edit.old.end,
3347            edit.new.start..edit.new.end
3348        );
3349
3350        // Record which hunks were previously expanded.
3351        while let Some(item) = old_diff_transforms.item() {
3352            if let Some(hunk_info) = item.hunk_info() {
3353                log::trace!(
3354                    "previously expanded hunk at {:?}",
3355                    old_diff_transforms.start()
3356                );
3357                old_expanded_hunks.insert(hunk_info);
3358            }
3359            if old_diff_transforms.end().0 > edit.old.end {
3360                break;
3361            }
3362            old_diff_transforms.next();
3363        }
3364
3365        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3366        // For inverted diffs, hunks are always shown, so we can't skip this.
3367        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3368        if old_expanded_hunks.is_empty()
3369            && change_kind == DiffChangeKind::BufferEdited
3370            && !all_diff_hunks_expanded
3371            && !snapshot.has_inverted_diff
3372        {
3373            return false;
3374        }
3375
3376        // Visit each excerpt that intersects the edit.
3377        let mut did_expand_hunks = false;
3378        while let Some(excerpt) = excerpts.item() {
3379            // Recompute the expanded hunks in the portion of the excerpt that
3380            // intersects the edit.
3381            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3382                let buffer = &excerpt.buffer;
3383                let excerpt_start = *excerpts.start();
3384                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3385                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3386                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3387                let edit_buffer_start =
3388                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3389                let edit_buffer_end =
3390                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3391                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3392
3393                if diff.is_inverted {
3394                    for hunk in diff.hunks_intersecting_base_text_range(
3395                        edit_buffer_start..edit_buffer_end,
3396                        diff.original_buffer_snapshot(),
3397                    ) {
3398                        did_expand_hunks = true;
3399                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3400                        if hunk_buffer_range.start < excerpt_buffer_start {
3401                            log::trace!("skipping hunk that starts before excerpt");
3402                            continue;
3403                        }
3404                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3405                        let hunk_excerpt_start = excerpt_start
3406                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3407                        let hunk_excerpt_end = excerpt_end
3408                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3409                        Self::push_buffer_content_transform(
3410                            snapshot,
3411                            new_diff_transforms,
3412                            hunk_excerpt_start,
3413                            *end_of_current_insert,
3414                        );
3415                        if !hunk_buffer_range.is_empty() {
3416                            let hunk_info = DiffTransformHunkInfo {
3417                                excerpt_id: excerpt.id,
3418                                hunk_start_anchor: hunk.buffer_range.start,
3419                                hunk_secondary_status: hunk.secondary_status,
3420                                is_logically_deleted: true,
3421                            };
3422                            *end_of_current_insert =
3423                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3424                        }
3425                    }
3426                } else {
3427                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3428                        ..buffer.anchor_after(edit_buffer_end);
3429                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3430                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3431                            continue;
3432                        }
3433
3434                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3435                        if hunk_buffer_range.start < excerpt_buffer_start {
3436                            log::trace!("skipping hunk that starts before excerpt");
3437                            continue;
3438                        }
3439
3440                        let hunk_info = DiffTransformHunkInfo {
3441                            excerpt_id: excerpt.id,
3442                            hunk_start_anchor: hunk.buffer_range.start,
3443                            hunk_secondary_status: hunk.secondary_status,
3444                            is_logically_deleted: false,
3445                        };
3446
3447                        let hunk_excerpt_start = excerpt_start
3448                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3449                        let hunk_excerpt_end = excerpt_end
3450                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3451
3452                        Self::push_buffer_content_transform(
3453                            snapshot,
3454                            new_diff_transforms,
3455                            hunk_excerpt_start,
3456                            *end_of_current_insert,
3457                        );
3458
3459                        // For every existing hunk, determine if it was previously expanded
3460                        // and if it should currently be expanded.
3461                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3462                        let should_expand_hunk = match &change_kind {
3463                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3464                                was_previously_expanded || all_diff_hunks_expanded
3465                            }
3466                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3467                                let intersects = hunk_buffer_range.is_empty()
3468                                    || hunk_buffer_range.end > edit_buffer_start;
3469                                if *expand {
3470                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3471                                } else {
3472                                    !intersects
3473                                        && (was_previously_expanded || all_diff_hunks_expanded)
3474                                }
3475                            }
3476                            _ => was_previously_expanded || all_diff_hunks_expanded,
3477                        };
3478
3479                        if should_expand_hunk {
3480                            did_expand_hunks = true;
3481                            log::trace!(
3482                                "expanding hunk {:?}, excerpt:{:?}",
3483                                hunk_excerpt_start..hunk_excerpt_end,
3484                                excerpt.id
3485                            );
3486
3487                            if !hunk.diff_base_byte_range.is_empty()
3488                                && hunk_buffer_range.start >= edit_buffer_start
3489                                && hunk_buffer_range.start <= excerpt_buffer_end
3490                                && snapshot.show_deleted_hunks
3491                            {
3492                                let base_text = diff.base_text();
3493                                let mut text_cursor =
3494                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3495                                let mut base_text_summary = text_cursor
3496                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3497
3498                                let mut has_trailing_newline = false;
3499                                if base_text_summary.last_line_chars > 0 {
3500                                    base_text_summary += TextSummary::newline();
3501                                    has_trailing_newline = true;
3502                                }
3503
3504                                new_diff_transforms.push(
3505                                    DiffTransform::DeletedHunk {
3506                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3507                                        summary: base_text_summary,
3508                                        buffer_id: excerpt.buffer_id,
3509                                        hunk_info,
3510                                        has_trailing_newline,
3511                                    },
3512                                    (),
3513                                );
3514                            }
3515
3516                            if !hunk_buffer_range.is_empty() {
3517                                *end_of_current_insert =
3518                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3519                            }
3520                        }
3521                    }
3522                }
3523            }
3524
3525            if excerpts.end() <= edit.new.end {
3526                excerpts.next();
3527            } else {
3528                break;
3529            }
3530        }
3531
3532        did_expand_hunks || !old_expanded_hunks.is_empty()
3533    }
3534
3535    fn append_diff_transforms(
3536        new_transforms: &mut SumTree<DiffTransform>,
3537        subtree: SumTree<DiffTransform>,
3538    ) {
3539        if let Some(DiffTransform::BufferContent {
3540            inserted_hunk_info,
3541            summary,
3542        }) = subtree.first()
3543            && Self::extend_last_buffer_content_transform(
3544                new_transforms,
3545                *inserted_hunk_info,
3546                *summary,
3547            )
3548        {
3549            let mut cursor = subtree.cursor::<()>(());
3550            cursor.next();
3551            cursor.next();
3552            new_transforms.append(cursor.suffix(), ());
3553            return;
3554        }
3555        new_transforms.append(subtree, ());
3556    }
3557
3558    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3559        if let DiffTransform::BufferContent {
3560            inserted_hunk_info: inserted_hunk_anchor,
3561            summary,
3562        } = transform
3563            && Self::extend_last_buffer_content_transform(
3564                new_transforms,
3565                inserted_hunk_anchor,
3566                summary,
3567            )
3568        {
3569            return;
3570        }
3571        new_transforms.push(transform, ());
3572    }
3573
3574    fn push_buffer_content_transform(
3575        old_snapshot: &MultiBufferSnapshot,
3576        new_transforms: &mut SumTree<DiffTransform>,
3577        end_offset: ExcerptOffset,
3578        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3579    ) {
3580        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3581            (end_offset.min(insertion_end_offset), Some(hunk_info))
3582        });
3583        let unchanged_region = [(end_offset, None)];
3584
3585        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3586        {
3587            let start_offset = new_transforms.summary().excerpt_len();
3588            if end_offset <= start_offset {
3589                continue;
3590            }
3591            let summary_to_add = old_snapshot
3592                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3593
3594            if !Self::extend_last_buffer_content_transform(
3595                new_transforms,
3596                inserted_hunk_info,
3597                summary_to_add,
3598            ) {
3599                new_transforms.push(
3600                    DiffTransform::BufferContent {
3601                        summary: summary_to_add,
3602                        inserted_hunk_info,
3603                    },
3604                    (),
3605                )
3606            }
3607        }
3608    }
3609
3610    fn extend_last_buffer_content_transform(
3611        new_transforms: &mut SumTree<DiffTransform>,
3612        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3613        summary_to_add: MBTextSummary,
3614    ) -> bool {
3615        let mut did_extend = false;
3616        new_transforms.update_last(
3617            |last_transform| {
3618                if let DiffTransform::BufferContent {
3619                    summary,
3620                    inserted_hunk_info: inserted_hunk_anchor,
3621                } = last_transform
3622                    && *inserted_hunk_anchor == new_inserted_hunk_info
3623                {
3624                    *summary += summary_to_add;
3625                    did_extend = true;
3626                }
3627            },
3628            (),
3629        );
3630        did_extend
3631    }
3632}
3633
3634fn build_excerpt_ranges(
3635    ranges: impl IntoIterator<Item = Range<Point>>,
3636    context_line_count: u32,
3637    buffer_snapshot: &BufferSnapshot,
3638) -> Vec<ExcerptRange<Point>> {
3639    ranges
3640        .into_iter()
3641        .map(|range| {
3642            let start_row = range.start.row.saturating_sub(context_line_count);
3643            let start = Point::new(start_row, 0);
3644            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3645            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3646            ExcerptRange {
3647                context: start..end,
3648                primary: range,
3649            }
3650        })
3651        .collect()
3652}
3653
3654#[cfg(any(test, feature = "test-support"))]
3655impl MultiBuffer {
3656    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3657        let buffer = cx.new(|cx| Buffer::local(text, cx));
3658        cx.new(|cx| Self::singleton(buffer, cx))
3659    }
3660
3661    pub fn build_multi<const COUNT: usize>(
3662        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3663        cx: &mut gpui::App,
3664    ) -> Entity<Self> {
3665        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3666        for (text, ranges) in excerpts {
3667            let buffer = cx.new(|cx| Buffer::local(text, cx));
3668            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3669            multi.update(cx, |multi, cx| {
3670                multi.push_excerpts(buffer, excerpt_ranges, cx)
3671            });
3672        }
3673
3674        multi
3675    }
3676
3677    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3678        cx.new(|cx| Self::singleton(buffer, cx))
3679    }
3680
3681    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3682        cx.new(|cx| {
3683            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3684            let mutation_count = rng.random_range(1..=5);
3685            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3686            multibuffer
3687        })
3688    }
3689
3690    pub fn randomly_edit(
3691        &mut self,
3692        rng: &mut impl rand::Rng,
3693        edit_count: usize,
3694        cx: &mut Context<Self>,
3695    ) {
3696        use util::RandomCharIter;
3697
3698        let snapshot = self.read(cx);
3699        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3700        let mut last_end = None;
3701        for _ in 0..edit_count {
3702            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3703                break;
3704            }
3705
3706            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3707            let end =
3708                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3709            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3710            last_end = Some(end);
3711
3712            let mut range = start..end;
3713            if rng.random_bool(0.2) {
3714                mem::swap(&mut range.start, &mut range.end);
3715            }
3716
3717            let new_text_len = rng.random_range(0..10);
3718            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3719
3720            edits.push((range, new_text.into()));
3721        }
3722        log::info!("mutating multi-buffer with {:?}", edits);
3723        drop(snapshot);
3724
3725        self.edit(edits, None, cx);
3726    }
3727
3728    pub fn randomly_edit_excerpts(
3729        &mut self,
3730        rng: &mut impl rand::Rng,
3731        mutation_count: usize,
3732        cx: &mut Context<Self>,
3733    ) {
3734        use rand::prelude::*;
3735        use std::env;
3736        use util::RandomCharIter;
3737
3738        let max_excerpts = env::var("MAX_EXCERPTS")
3739            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3740            .unwrap_or(5);
3741
3742        let mut buffers = Vec::new();
3743        for _ in 0..mutation_count {
3744            if rng.random_bool(0.05) {
3745                log::info!("Clearing multi-buffer");
3746                self.clear(cx);
3747                continue;
3748            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3749                let ids = self.excerpt_ids();
3750                let mut excerpts = HashSet::default();
3751                for _ in 0..rng.random_range(0..ids.len()) {
3752                    excerpts.extend(ids.choose(rng).copied());
3753                }
3754
3755                let line_count = rng.random_range(0..5);
3756
3757                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3758
3759                self.expand_excerpts(
3760                    excerpts.iter().cloned(),
3761                    line_count,
3762                    ExpandExcerptDirection::UpAndDown,
3763                    cx,
3764                );
3765                continue;
3766            }
3767
3768            let excerpt_ids = self.excerpt_ids();
3769            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3770                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3771                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3772                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3773                    let buffer = buffers.last().unwrap().read(cx);
3774                    log::info!(
3775                        "Creating new buffer {} with text: {:?}",
3776                        buffer.remote_id(),
3777                        buffer.text()
3778                    );
3779                    buffers.last().unwrap().clone()
3780                } else {
3781                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3782                };
3783
3784                let buffer = buffer_handle.read(cx);
3785                let buffer_text = buffer.text();
3786                let ranges = (0..rng.random_range(0..5))
3787                    .map(|_| {
3788                        let end_ix =
3789                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3790                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3791                        ExcerptRange::new(start_ix..end_ix)
3792                    })
3793                    .collect::<Vec<_>>();
3794                log::info!(
3795                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3796                    buffer_handle.read(cx).remote_id(),
3797                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3798                    ranges
3799                        .iter()
3800                        .map(|r| &buffer_text[r.context.clone()])
3801                        .collect::<Vec<_>>()
3802                );
3803
3804                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3805                log::info!("Inserted with ids: {:?}", excerpt_id);
3806            } else {
3807                let remove_count = rng.random_range(1..=excerpt_ids.len());
3808                let mut excerpts_to_remove = excerpt_ids
3809                    .choose_multiple(rng, remove_count)
3810                    .cloned()
3811                    .collect::<Vec<_>>();
3812                let snapshot = self.snapshot.borrow();
3813                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3814                drop(snapshot);
3815                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3816                self.remove_excerpts(excerpts_to_remove, cx);
3817            }
3818        }
3819    }
3820
3821    pub fn randomly_mutate(
3822        &mut self,
3823        rng: &mut impl rand::Rng,
3824        mutation_count: usize,
3825        cx: &mut Context<Self>,
3826    ) {
3827        use rand::prelude::*;
3828
3829        if rng.random_bool(0.7) || self.singleton {
3830            let buffer = self
3831                .buffers
3832                .values()
3833                .choose(rng)
3834                .map(|state| state.buffer.clone());
3835
3836            if let Some(buffer) = buffer {
3837                buffer.update(cx, |buffer, cx| {
3838                    if rng.random() {
3839                        buffer.randomly_edit(rng, mutation_count, cx);
3840                    } else {
3841                        buffer.randomly_undo_redo(rng, cx);
3842                    }
3843                });
3844            } else {
3845                self.randomly_edit(rng, mutation_count, cx);
3846            }
3847        } else {
3848            self.randomly_edit_excerpts(rng, mutation_count, cx);
3849        }
3850
3851        self.check_invariants(cx);
3852    }
3853
3854    fn check_invariants(&self, cx: &App) {
3855        self.read(cx).check_invariants();
3856    }
3857}
3858
3859impl EventEmitter<Event> for MultiBuffer {}
3860
3861impl MultiBufferSnapshot {
3862    pub fn text(&self) -> String {
3863        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3864            .map(|chunk| chunk.text)
3865            .collect()
3866    }
3867
3868    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3869        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3870            .flat_map(|c| c.chars().rev())
3871    }
3872
3873    fn reversed_chunks_in_range(
3874        &self,
3875        range: Range<MultiBufferOffset>,
3876    ) -> ReversedMultiBufferChunks<'_> {
3877        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3878        cursor.seek(&range.end);
3879        let current_chunks = cursor.region().as_ref().map(|region| {
3880            let start_overshoot = range.start.saturating_sub(region.range.start);
3881            let end_overshoot = range.end - region.range.start;
3882            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3883            let start = region.buffer_range.start + start_overshoot;
3884            region.buffer.reversed_chunks_in_range(start..end)
3885        });
3886        ReversedMultiBufferChunks {
3887            cursor,
3888            current_chunks,
3889            start: range.start,
3890            offset: range.end,
3891        }
3892    }
3893
3894    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3895        let offset = position.to_offset(self);
3896        self.text_for_range(offset..self.len())
3897            .flat_map(|chunk| chunk.chars())
3898    }
3899
3900    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3901        self.chunks(range, false).map(|chunk| chunk.text)
3902    }
3903
3904    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3905        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3906            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3907    }
3908
3909    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3910    where
3911        T: ToOffset,
3912    {
3913        let position = position.to_offset(self);
3914        position == self.clip_offset(position, Bias::Left)
3915            && self
3916                .bytes_in_range(position..self.len())
3917                .flatten()
3918                .copied()
3919                .take(needle.len())
3920                .eq(needle.bytes())
3921    }
3922
3923    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3924        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3925    }
3926
3927    pub fn diff_hunks_in_range<T: ToPoint>(
3928        &self,
3929        range: Range<T>,
3930    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3931        let query_range = range.start.to_point(self)..range.end.to_point(self);
3932        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3933            let diff = self.diffs.get(&buffer.remote_id())?;
3934            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3935                if diff.is_inverted {
3936                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3937                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3938                    Box::new(
3939                        diff.hunks_intersecting_base_text_range(
3940                            buffer_start..buffer_end,
3941                            diff.original_buffer_snapshot(),
3942                        )
3943                        .map(move |hunk| (hunk, buffer, true)),
3944                    )
3945                } else {
3946                    let buffer_start = buffer.anchor_before(buffer_range.start);
3947                    let buffer_end = buffer.anchor_after(buffer_range.end);
3948                    Box::new(
3949                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3950                            .map(move |hunk| (hunk, buffer, false)),
3951                    )
3952                };
3953            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3954                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3955                    return None;
3956                }
3957                let range = if is_inverted {
3958                    hunk.diff_base_byte_range.to_point(&buffer)
3959                } else {
3960                    hunk.range.clone()
3961                };
3962                Some((range, (hunk, is_inverted)))
3963            }))
3964        })
3965        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3966            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3967            {
3968                return None;
3969            }
3970            let end_row = if range.end.column == 0 {
3971                range.end.row
3972            } else {
3973                range.end.row + 1
3974            };
3975
3976            let word_diffs =
3977                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3978                    .then(|| {
3979                        let mut word_diffs = Vec::new();
3980
3981                        if self.show_deleted_hunks || is_inverted {
3982                            let hunk_start_offset = if is_inverted {
3983                                Anchor::in_buffer(
3984                                    excerpt.id,
3985                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3986                                )
3987                                .to_offset(self)
3988                            } else {
3989                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3990                                    .to_offset(self)
3991                            };
3992
3993                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3994                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3995                            }));
3996                        }
3997
3998                        if !is_inverted {
3999                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4000                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4001                            }));
4002                        }
4003                        word_diffs
4004                    })
4005                    .unwrap_or_default();
4006
4007            let buffer_range = if is_inverted {
4008                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4009                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4010            } else {
4011                hunk.buffer_range.clone()
4012            };
4013            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4014                DiffHunkStatusKind::Deleted
4015            } else if hunk.diff_base_byte_range.is_empty() {
4016                DiffHunkStatusKind::Added
4017            } else {
4018                DiffHunkStatusKind::Modified
4019            };
4020            Some(MultiBufferDiffHunk {
4021                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4022                buffer_id: excerpt.buffer_id,
4023                excerpt_id: excerpt.id,
4024                buffer_range,
4025                word_diffs,
4026                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4027                    ..BufferOffset(hunk.diff_base_byte_range.end),
4028                status: DiffHunkStatus {
4029                    kind: status_kind,
4030                    secondary: hunk.secondary_status,
4031                },
4032            })
4033        })
4034    }
4035
4036    fn excerpts_for_range<T: ToOffset>(
4037        &self,
4038        range: Range<T>,
4039    ) -> impl Iterator<Item = &Excerpt> + '_ {
4040        let range = range.start.to_offset(self)..range.end.to_offset(self);
4041        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4042        cursor.seek(&range.start);
4043        std::iter::from_fn(move || {
4044            let region = cursor.region()?;
4045            if region.range.start > range.end
4046                || region.range.start == range.end && region.range.start > range.start
4047            {
4048                return None;
4049            }
4050            let excerpt = region.excerpt;
4051            cursor.next_excerpt_forwards();
4052            Some(excerpt)
4053        })
4054    }
4055
4056    pub fn excerpt_ids_for_range<T: ToOffset>(
4057        &self,
4058        range: Range<T>,
4059    ) -> impl Iterator<Item = ExcerptId> + '_ {
4060        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4061    }
4062
4063    pub fn buffer_ids_for_range<T: ToOffset>(
4064        &self,
4065        range: Range<T>,
4066    ) -> impl Iterator<Item = BufferId> + '_ {
4067        self.excerpts_for_range(range)
4068            .map(|excerpt| excerpt.buffer_id)
4069    }
4070
4071    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4072    ///
4073    /// The passed in anchors must be ordered.
4074    pub fn text_anchors_to_visible_anchors(
4075        &self,
4076        anchors: impl IntoIterator<Item = text::Anchor>,
4077    ) -> Vec<Option<Anchor>> {
4078        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4079        let mut anchors = anchors.into_iter().peekable();
4080        let mut result = Vec::new();
4081        'anchors: while let Some(anchor) = anchors.peek() {
4082            let Some(buffer_id) = anchor.buffer_id else {
4083                anchors.next();
4084                result.push(None);
4085                continue 'anchors;
4086            };
4087            let mut same_buffer_anchors =
4088                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4089
4090            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4091                let Some(mut next) = same_buffer_anchors.next() else {
4092                    continue 'anchors;
4093                };
4094                'excerpts: for locator in locators.iter() {
4095                    if cursor.seek_forward(&Some(locator), Bias::Left)
4096                        && let Some(excerpt) = cursor.item()
4097                    {
4098                        loop {
4099                            // anchor is before the first excerpt
4100                            if excerpt
4101                                .range
4102                                .context
4103                                .start
4104                                .cmp(&next, &excerpt.buffer)
4105                                .is_gt()
4106                            {
4107                                // so we skip it and try the next anchor
4108                                result.push(None);
4109                                match same_buffer_anchors.next() {
4110                                    Some(anchor) => next = anchor,
4111                                    None => continue 'anchors,
4112                                }
4113                            // anchor is within the excerpt
4114                            } else if excerpt
4115                                .range
4116                                .context
4117                                .end
4118                                .cmp(&next, &excerpt.buffer)
4119                                .is_ge()
4120                            {
4121                                // record it and all following anchors that are within
4122                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4123                                result.extend(
4124                                    same_buffer_anchors
4125                                        .peeking_take_while(|a| {
4126                                            excerpt
4127                                                .range
4128                                                .context
4129                                                .end
4130                                                .cmp(a, &excerpt.buffer)
4131                                                .is_ge()
4132                                        })
4133                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4134                                );
4135                                match same_buffer_anchors.next() {
4136                                    Some(anchor) => next = anchor,
4137                                    None => continue 'anchors,
4138                                }
4139                            // anchor is after the excerpt, try the next one
4140                            } else {
4141                                continue 'excerpts;
4142                            }
4143                        }
4144                    }
4145                }
4146                // account for `next`
4147                result.push(None);
4148            }
4149            result.extend(same_buffer_anchors.map(|_| None));
4150        }
4151
4152        result
4153    }
4154
4155    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4156        &self,
4157        ranges: impl Iterator<Item = Range<T>>,
4158    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4159        ranges.flat_map(|range| {
4160            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4161                .into_iter()
4162        })
4163    }
4164
4165    pub fn range_to_buffer_ranges<R, T>(
4166        &self,
4167        range: R,
4168    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4169    where
4170        R: RangeBounds<T>,
4171        T: ToOffset,
4172    {
4173        self.range_to_buffer_ranges_with_context(range)
4174            .into_iter()
4175            .map(|(buffer, range, id, _context)| (buffer, range, id))
4176            .collect()
4177    }
4178
4179    pub fn range_to_buffer_ranges_with_context<R, T>(
4180        &self,
4181        range: R,
4182    ) -> Vec<(
4183        &BufferSnapshot,
4184        Range<BufferOffset>,
4185        ExcerptId,
4186        Range<text::Anchor>,
4187    )>
4188    where
4189        R: RangeBounds<T>,
4190        T: ToOffset,
4191    {
4192        let start = match range.start_bound() {
4193            Bound::Included(start) => start.to_offset(self),
4194            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4195            Bound::Unbounded => MultiBufferOffset::ZERO,
4196        };
4197        let end_bound = match range.end_bound() {
4198            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4199            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4200            Bound::Unbounded => Bound::Unbounded,
4201        };
4202        let bounds = (Bound::Included(start), end_bound);
4203
4204        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4205        cursor.seek(&start);
4206
4207        let mut result: Vec<(
4208            &BufferSnapshot,
4209            Range<BufferOffset>,
4210            ExcerptId,
4211            Range<text::Anchor>,
4212        )> = Vec::new();
4213        while let Some(region) = cursor.region() {
4214            let dominated_by_end_bound = match end_bound {
4215                Bound::Included(end) => region.range.start > end,
4216                Bound::Excluded(end) => region.range.start >= end,
4217                Bound::Unbounded => false,
4218            };
4219            if dominated_by_end_bound {
4220                break;
4221            }
4222            if region.is_main_buffer {
4223                let start_overshoot = start.saturating_sub(region.range.start);
4224                let end_offset = match end_bound {
4225                    Bound::Included(end) | Bound::Excluded(end) => end,
4226                    Bound::Unbounded => region.range.end,
4227                };
4228                let end_overshoot = end_offset.saturating_sub(region.range.start);
4229                let start = region
4230                    .buffer_range
4231                    .end
4232                    .min(region.buffer_range.start + start_overshoot);
4233                let end = region
4234                    .buffer_range
4235                    .end
4236                    .min(region.buffer_range.start + end_overshoot);
4237                let context = region.excerpt.range.context.clone();
4238                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4239                    *excerpt_id == region.excerpt.id && prev_range.end == start
4240                }) {
4241                    prev.1.end = end;
4242                } else {
4243                    result.push((region.buffer, start..end, region.excerpt.id, context));
4244                }
4245            }
4246            cursor.next();
4247        }
4248
4249        if let Some(excerpt) = cursor.excerpt() {
4250            let dominated_by_prev_excerpt =
4251                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4252            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4253                let excerpt_position = self.len();
4254                if bounds.contains(&excerpt_position) {
4255                    let buffer_offset =
4256                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4257                    let context = excerpt.range.context.clone();
4258                    result.push((
4259                        &excerpt.buffer,
4260                        buffer_offset..buffer_offset,
4261                        excerpt.id,
4262                        context,
4263                    ));
4264                }
4265            }
4266        }
4267
4268        result
4269    }
4270
4271    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4272        &self,
4273        range: Range<T>,
4274    ) -> impl Iterator<
4275        Item = (
4276            &BufferSnapshot,
4277            Range<BufferOffset>,
4278            ExcerptId,
4279            Option<Anchor>,
4280        ),
4281    > + '_ {
4282        let start = range.start.to_offset(self);
4283        let end = range.end.to_offset(self);
4284
4285        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4286        cursor.seek(&start);
4287
4288        std::iter::from_fn(move || {
4289            let region = cursor.region()?;
4290            if region.range.start > end {
4291                return None;
4292            }
4293            let start_overshoot = start.saturating_sub(region.range.start);
4294            let end_overshoot = end.saturating_sub(region.range.start);
4295            let start = region
4296                .buffer_range
4297                .end
4298                .min(region.buffer_range.start + start_overshoot);
4299            let end = region
4300                .buffer_range
4301                .end
4302                .min(region.buffer_range.start + end_overshoot);
4303
4304            let region_excerpt_id = region.excerpt.id;
4305            let deleted_hunk_anchor = if region.is_main_buffer {
4306                None
4307            } else {
4308                Some(self.anchor_before(region.range.start))
4309            };
4310            let result = (
4311                region.buffer,
4312                start..end,
4313                region_excerpt_id,
4314                deleted_hunk_anchor,
4315            );
4316            cursor.next();
4317            Some(result)
4318        })
4319    }
4320
4321    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4322    /// coordinates.
4323    ///
4324    /// The given callback will be called for every excerpt intersecting the given range. It will
4325    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4326    /// The callback should return an iterator of metadata items from that buffer, each paired
4327    /// with a buffer range.
4328    ///
4329    /// The returned iterator yields each of these metadata items, paired with its range in
4330    /// multi-buffer coordinates.
4331    fn lift_buffer_metadata<'a, MBD, M, I>(
4332        &'a self,
4333        query_range: Range<MBD>,
4334        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4335    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4336    where
4337        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4338        MBD: MultiBufferDimension
4339            + Ord
4340            + Sub<Output = MBD::TextDimension>
4341            + ops::Add<MBD::TextDimension, Output = MBD>
4342            + ops::AddAssign<MBD::TextDimension>,
4343        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4344            + ops::Add<Output = MBD::TextDimension>
4345            + AddAssign<MBD::TextDimension>
4346            + Ord,
4347    {
4348        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4349        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4350
4351        // Find the excerpt and buffer offset where the given range ends.
4352        cursor.seek(&query_range.end);
4353        let mut range_end = None;
4354        while let Some(region) = cursor.region() {
4355            if region.is_main_buffer {
4356                let mut buffer_end = region.buffer_range.start;
4357                let overshoot = if query_range.end > region.range.start {
4358                    query_range.end - region.range.start
4359                } else {
4360                    <MBD::TextDimension>::default()
4361                };
4362                buffer_end = buffer_end + overshoot;
4363                range_end = Some((region.excerpt.id, buffer_end));
4364                break;
4365            }
4366            cursor.next();
4367        }
4368
4369        cursor.seek(&query_range.start);
4370
4371        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4372            && region.range.start > MBD::default()
4373        {
4374            cursor.prev()
4375        } else if let Some(region) = cursor.region()
4376            && region.is_main_buffer
4377            && region.diff_hunk_status.is_some()
4378        {
4379            cursor.prev();
4380            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4381                cursor.next();
4382            }
4383        }
4384
4385        iter::from_fn(move || {
4386            loop {
4387                let excerpt = cursor.excerpt()?;
4388
4389                // If we have already retrieved metadata for this excerpt, continue to use it.
4390                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4391                    .as_mut()
4392                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4393                {
4394                    Some(metadata)
4395                }
4396                // Otherwise, compute the intersection of the input range with the excerpt's range,
4397                // and retrieve the metadata for the resulting range.
4398                else {
4399                    let region = cursor.region()?;
4400                    let mut buffer_start;
4401                    if region.is_main_buffer {
4402                        buffer_start = region.buffer_range.start;
4403                        if query_range.start > region.range.start {
4404                            let overshoot = query_range.start - region.range.start;
4405                            buffer_start = buffer_start + overshoot;
4406                        }
4407                        buffer_start = buffer_start.min(region.buffer_range.end);
4408                    } else {
4409                        buffer_start = cursor.main_buffer_position()?;
4410                    };
4411                    let mut buffer_end = excerpt
4412                        .range
4413                        .context
4414                        .end
4415                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4416                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4417                        && excerpt.id == end_excerpt_id
4418                    {
4419                        buffer_end = buffer_end.min(end_buffer_offset);
4420                    }
4421
4422                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4423                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4424                    })
4425                };
4426
4427                // Visit each metadata item.
4428                if let Some((metadata_buffer_range, metadata)) =
4429                    metadata_iter.and_then(Iterator::next)
4430                {
4431                    // Find the multibuffer regions that contain the start and end of
4432                    // the metadata item's range.
4433                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4434                        while let Some(region) = cursor.region() {
4435                            if (region.is_main_buffer
4436                                && (region.buffer_range.end >= metadata_buffer_range.start
4437                                    || cursor.is_at_end_of_excerpt()))
4438                                || (!region.is_main_buffer
4439                                    && region.buffer_range.start == metadata_buffer_range.start)
4440                            {
4441                                break;
4442                            }
4443                            cursor.next();
4444                        }
4445                    }
4446                    let start_region = cursor.region()?.clone();
4447                    while let Some(region) = cursor.region() {
4448                        if region.is_main_buffer
4449                            && (region.buffer_range.end > metadata_buffer_range.end
4450                                || cursor.is_at_end_of_excerpt())
4451                        {
4452                            break;
4453                        }
4454                        cursor.next();
4455                    }
4456                    let end_region = cursor.region();
4457
4458                    // Convert the metadata item's range into multibuffer coordinates.
4459                    let mut start_position = start_region.range.start;
4460                    let region_buffer_start = start_region.buffer_range.start;
4461                    if start_region.is_main_buffer
4462                        && metadata_buffer_range.start > region_buffer_start
4463                    {
4464                        start_position =
4465                            start_position + (metadata_buffer_range.start - region_buffer_start);
4466                        start_position = start_position.min(start_region.range.end);
4467                    }
4468
4469                    let mut end_position = self.max_position();
4470                    if let Some(end_region) = &end_region {
4471                        end_position = end_region.range.start;
4472                        debug_assert!(end_region.is_main_buffer);
4473                        let region_buffer_start = end_region.buffer_range.start;
4474                        if metadata_buffer_range.end > region_buffer_start {
4475                            end_position =
4476                                end_position + (metadata_buffer_range.end - region_buffer_start);
4477                        }
4478                        end_position = end_position.min(end_region.range.end);
4479                    }
4480
4481                    if start_position <= query_range.end && end_position >= query_range.start {
4482                        return Some((start_position..end_position, metadata, excerpt));
4483                    }
4484                }
4485                // When there are no more metadata items for this excerpt, move to the next excerpt.
4486                else {
4487                    current_excerpt_metadata.take();
4488                    if let Some((end_excerpt_id, _)) = range_end
4489                        && excerpt.id == end_excerpt_id
4490                    {
4491                        return None;
4492                    }
4493                    cursor.next_excerpt_forwards();
4494                }
4495            }
4496        })
4497    }
4498
4499    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4500        let offset = position.to_offset(self);
4501
4502        let mut cursor = self
4503            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4504            );
4505        cursor.seek(&DimensionPair {
4506            key: offset,
4507            value: None,
4508        });
4509        cursor.seek_to_start_of_current_excerpt();
4510        let excerpt = cursor.excerpt()?;
4511
4512        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4513        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4514        let current_position = self
4515            .anchor_before(offset)
4516            .text_anchor
4517            .to_offset(&excerpt.buffer);
4518
4519        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4520            if diff.is_inverted {
4521                for hunk in diff.hunks_intersecting_base_text_range_rev(
4522                    excerpt_start..excerpt_end,
4523                    diff.original_buffer_snapshot(),
4524                ) {
4525                    if hunk.diff_base_byte_range.end >= current_position {
4526                        continue;
4527                    }
4528                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4529                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4530                    return Some(MultiBufferRow(start.row));
4531                }
4532            } else {
4533                let excerpt_end = excerpt
4534                    .buffer
4535                    .anchor_before(excerpt_end.min(current_position));
4536                for hunk in diff.hunks_intersecting_range_rev(
4537                    excerpt.range.context.start..excerpt_end,
4538                    &excerpt.buffer,
4539                ) {
4540                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4541                    if hunk_end >= current_position {
4542                        continue;
4543                    }
4544                    let start =
4545                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4546                    return Some(MultiBufferRow(start.row));
4547                }
4548            }
4549        }
4550
4551        loop {
4552            cursor.prev_excerpt();
4553            let excerpt = cursor.excerpt()?;
4554
4555            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4556                continue;
4557            };
4558            if diff.is_inverted {
4559                let Some(hunk) = diff
4560                    .hunks_intersecting_base_text_range_rev(
4561                        excerpt.range.context.to_offset(&excerpt.buffer),
4562                        diff.original_buffer_snapshot(),
4563                    )
4564                    .next()
4565                else {
4566                    continue;
4567                };
4568                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4569                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4570                return Some(MultiBufferRow(start.row));
4571            } else {
4572                let Some(hunk) = diff
4573                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4574                    .next()
4575                else {
4576                    continue;
4577                };
4578                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4579                return Some(MultiBufferRow(start.row));
4580            }
4581        }
4582    }
4583
4584    pub fn has_diff_hunks(&self) -> bool {
4585        self.diffs.values().any(|diff| !diff.is_empty())
4586    }
4587
4588    pub fn is_inside_word<T: ToOffset>(
4589        &self,
4590        position: T,
4591        scope_context: Option<CharScopeContext>,
4592    ) -> bool {
4593        let position = position.to_offset(self);
4594        let classifier = self
4595            .char_classifier_at(position)
4596            .scope_context(scope_context);
4597        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4598        let prev_char_kind = self
4599            .reversed_chars_at(position)
4600            .next()
4601            .map(|c| classifier.kind(c));
4602        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4603    }
4604
4605    pub fn surrounding_word<T: ToOffset>(
4606        &self,
4607        start: T,
4608        scope_context: Option<CharScopeContext>,
4609    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4610        let mut start = start.to_offset(self);
4611        let mut end = start;
4612        let mut next_chars = self.chars_at(start).peekable();
4613        let mut prev_chars = self.reversed_chars_at(start).peekable();
4614
4615        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4616
4617        let word_kind = cmp::max(
4618            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4619            next_chars.peek().copied().map(|c| classifier.kind(c)),
4620        );
4621
4622        for ch in prev_chars {
4623            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4624                start -= ch.len_utf8();
4625            } else {
4626                break;
4627            }
4628        }
4629
4630        for ch in next_chars {
4631            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4632                end += ch.len_utf8();
4633            } else {
4634                break;
4635            }
4636        }
4637
4638        (start..end, word_kind)
4639    }
4640
4641    pub fn char_kind_before<T: ToOffset>(
4642        &self,
4643        start: T,
4644        scope_context: Option<CharScopeContext>,
4645    ) -> Option<CharKind> {
4646        let start = start.to_offset(self);
4647        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4648        self.reversed_chars_at(start)
4649            .next()
4650            .map(|ch| classifier.kind(ch))
4651    }
4652
4653    pub fn is_singleton(&self) -> bool {
4654        self.singleton
4655    }
4656
4657    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4658        if self.singleton {
4659            self.excerpts
4660                .iter()
4661                .next()
4662                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4663        } else {
4664            None
4665        }
4666    }
4667
4668    pub fn len(&self) -> MultiBufferOffset {
4669        self.diff_transforms.summary().output.len
4670    }
4671
4672    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4673        MBD::from_summary(&self.text_summary())
4674    }
4675
4676    pub fn is_empty(&self) -> bool {
4677        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4678    }
4679
4680    pub fn widest_line_number(&self) -> u32 {
4681        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4682        self.excerpts.summary().widest_line_number + 1
4683    }
4684
4685    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4686        let range = range.start.to_offset(self)..range.end.to_offset(self);
4687        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4688        excerpts.seek(&range.start);
4689
4690        let mut chunk;
4691        let mut has_trailing_newline;
4692        let excerpt_bytes;
4693        if let Some(region) = excerpts.region() {
4694            let mut bytes = region.buffer.bytes_in_range(
4695                region.buffer_range.start + (range.start - region.range.start)
4696                    ..(region.buffer_range.start + (range.end - region.range.start))
4697                        .min(region.buffer_range.end),
4698            );
4699            chunk = bytes.next().unwrap_or(&[][..]);
4700            excerpt_bytes = Some(bytes);
4701            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4702            if chunk.is_empty() && has_trailing_newline {
4703                chunk = b"\n";
4704                has_trailing_newline = false;
4705            }
4706        } else {
4707            chunk = &[][..];
4708            excerpt_bytes = None;
4709            has_trailing_newline = false;
4710        };
4711
4712        MultiBufferBytes {
4713            range,
4714            cursor: excerpts,
4715            excerpt_bytes,
4716            has_trailing_newline,
4717            chunk,
4718        }
4719    }
4720
4721    pub fn reversed_bytes_in_range<T: ToOffset>(
4722        &self,
4723        range: Range<T>,
4724    ) -> ReversedMultiBufferBytes<'_> {
4725        let range = range.start.to_offset(self)..range.end.to_offset(self);
4726        let mut chunks = self.reversed_chunks_in_range(range.clone());
4727        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4728        ReversedMultiBufferBytes {
4729            range,
4730            chunks,
4731            chunk,
4732        }
4733    }
4734
4735    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4736        let mut cursor = self.cursor::<Point, Point>();
4737        cursor.seek(&Point::new(start_row.0, 0));
4738        let mut result = MultiBufferRows {
4739            point: Point::new(0, 0),
4740            is_empty: self.excerpts.is_empty(),
4741            is_singleton: self.is_singleton(),
4742            cursor,
4743        };
4744        result.seek(start_row);
4745        result
4746    }
4747
4748    pub fn chunks<T: ToOffset>(
4749        &self,
4750        range: Range<T>,
4751        language_aware: bool,
4752    ) -> MultiBufferChunks<'_> {
4753        let mut chunks = MultiBufferChunks {
4754            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4755                ..ExcerptDimension(MultiBufferOffset::ZERO),
4756            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4757            excerpts: self.excerpts.cursor(()),
4758            diff_transforms: self.diff_transforms.cursor(()),
4759            diffs: &self.diffs,
4760            diff_base_chunks: None,
4761            excerpt_chunks: None,
4762            buffer_chunk: None,
4763            language_aware,
4764        };
4765        let range = range.start.to_offset(self)..range.end.to_offset(self);
4766        chunks.seek(range);
4767        chunks
4768    }
4769
4770    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4771        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4772    }
4773
4774    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4775        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4776    }
4777
4778    pub fn clip_offset_utf16(
4779        &self,
4780        offset: MultiBufferOffsetUtf16,
4781        bias: Bias,
4782    ) -> MultiBufferOffsetUtf16 {
4783        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4784    }
4785
4786    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4787        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4788            buffer.clip_point_utf16(Unclipped(point), bias)
4789        })
4790    }
4791
4792    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4793        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4794    }
4795
4796    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4797        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4798    }
4799
4800    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4801        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4802    }
4803
4804    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4805        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4806    }
4807
4808    #[instrument(skip_all)]
4809    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4810        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4811    }
4812
4813    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4814        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4815    }
4816
4817    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4818        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4819    }
4820
4821    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4822        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4823    }
4824
4825    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4826        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4827    }
4828
4829    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4830        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4831    }
4832
4833    fn clip_dimension<MBD, BD>(
4834        &self,
4835        position: MBD,
4836        bias: Bias,
4837        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4838    ) -> MBD
4839    where
4840        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4841        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4842    {
4843        let mut cursor = self.cursor::<MBD, BD>();
4844        cursor.seek(&position);
4845        if let Some(region) = cursor.region() {
4846            if position >= region.range.end {
4847                return region.range.end;
4848            }
4849            let overshoot = position - region.range.start;
4850            let mut buffer_position = region.buffer_range.start;
4851            buffer_position += overshoot;
4852            let clipped_buffer_position =
4853                clip_buffer_position(region.buffer, buffer_position, bias);
4854            let mut position = region.range.start;
4855            position += clipped_buffer_position - region.buffer_range.start;
4856            position
4857        } else {
4858            self.max_position()
4859        }
4860    }
4861
4862    #[instrument(skip_all)]
4863    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4864        &self,
4865        key: MBR1,
4866        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4867    ) -> MBR2
4868    where
4869        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4870        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4871        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4872        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4873    {
4874        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4875        cursor.seek(&DimensionPair { key, value: None });
4876        if let Some(region) = cursor.region() {
4877            if key >= region.range.end.key {
4878                return region.range.end.value.unwrap();
4879            }
4880            let start_key = region.range.start.key;
4881            let start_value = region.range.start.value.unwrap();
4882            let buffer_start_key = region.buffer_range.start.key;
4883            let buffer_start_value = region.buffer_range.start.value.unwrap();
4884            let mut buffer_key = buffer_start_key;
4885            buffer_key += key - start_key;
4886            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4887            let mut result = start_value;
4888            result += buffer_value - buffer_start_value;
4889            result
4890        } else {
4891            self.max_position()
4892        }
4893    }
4894
4895    pub fn point_to_buffer_offset<T: ToOffset>(
4896        &self,
4897        point: T,
4898    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4899        let offset = point.to_offset(self);
4900        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4901        cursor.seek(&offset);
4902        let region = cursor.region()?;
4903        let overshoot = offset - region.range.start;
4904        let buffer_offset = region.buffer_range.start + overshoot;
4905        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4906            && region.has_trailing_newline
4907            && !region.is_main_buffer
4908        {
4909            let main_buffer_position = cursor.main_buffer_position()?;
4910            let buffer_snapshot = &cursor.excerpt()?.buffer;
4911            return Some((buffer_snapshot, main_buffer_position));
4912        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4913            return None;
4914        }
4915        Some((region.buffer, buffer_offset))
4916    }
4917
4918    pub fn point_to_buffer_point(
4919        &self,
4920        point: Point,
4921    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4922        let mut cursor = self.cursor::<Point, Point>();
4923        cursor.seek(&point);
4924        let region = cursor.region()?;
4925        let overshoot = point - region.range.start;
4926        let buffer_point = region.buffer_range.start + overshoot;
4927        let excerpt = cursor.excerpt()?;
4928        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4929            && region.has_trailing_newline
4930            && !region.is_main_buffer
4931        {
4932            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4933        } else if buffer_point > region.buffer.max_point() {
4934            return None;
4935        }
4936        Some((region.buffer, buffer_point, excerpt.id))
4937    }
4938
4939    pub fn suggested_indents(
4940        &self,
4941        rows: impl IntoIterator<Item = u32>,
4942        cx: &App,
4943    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4944        let mut result = BTreeMap::new();
4945        self.suggested_indents_callback(
4946            rows,
4947            |row, indent| {
4948                result.insert(row, indent);
4949                ControlFlow::Continue(())
4950            },
4951            cx,
4952        );
4953        result
4954    }
4955
4956    // move this to be a generator once those are a thing
4957    pub fn suggested_indents_callback(
4958        &self,
4959        rows: impl IntoIterator<Item = u32>,
4960        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4961        cx: &App,
4962    ) {
4963        let mut rows_for_excerpt = Vec::new();
4964        let mut cursor = self.cursor::<Point, Point>();
4965        let mut rows = rows.into_iter().peekable();
4966        let mut prev_row = u32::MAX;
4967        let mut prev_language_indent_size = IndentSize::default();
4968
4969        while let Some(row) = rows.next() {
4970            cursor.seek(&Point::new(row, 0));
4971            let Some(region) = cursor.region() else {
4972                continue;
4973            };
4974
4975            // Retrieve the language and indent size once for each disjoint region being indented.
4976            let single_indent_size = if row.saturating_sub(1) == prev_row {
4977                prev_language_indent_size
4978            } else {
4979                region
4980                    .buffer
4981                    .language_indent_size_at(Point::new(row, 0), cx)
4982            };
4983            prev_language_indent_size = single_indent_size;
4984            prev_row = row;
4985
4986            let start_buffer_row = region.buffer_range.start.row;
4987            let start_multibuffer_row = region.range.start.row;
4988            let end_multibuffer_row = region.range.end.row;
4989
4990            rows_for_excerpt.push(row);
4991            while let Some(next_row) = rows.peek().copied() {
4992                if end_multibuffer_row > next_row {
4993                    rows_for_excerpt.push(next_row);
4994                    rows.next();
4995                } else {
4996                    break;
4997                }
4998            }
4999
5000            let buffer_rows = rows_for_excerpt
5001                .drain(..)
5002                .map(|row| start_buffer_row + row - start_multibuffer_row);
5003            let buffer_indents = region
5004                .buffer
5005                .suggested_indents(buffer_rows, single_indent_size);
5006            for (row, indent) in buffer_indents {
5007                if cb(
5008                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5009                    indent,
5010                )
5011                .is_break()
5012                {
5013                    return;
5014                }
5015            }
5016        }
5017    }
5018
5019    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5020        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5021            let mut size = buffer.indent_size_for_line(range.start.row);
5022            size.len = size
5023                .len
5024                .min(range.end.column)
5025                .saturating_sub(range.start.column);
5026            size
5027        } else {
5028            IndentSize::spaces(0)
5029        }
5030    }
5031
5032    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5033        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5034            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5035        } else {
5036            LineIndent::spaces(0)
5037        }
5038    }
5039
5040    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5041        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5042
5043        if self.language_settings(cx).extend_comment_on_newline
5044            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5045        {
5046            let delimiters = language_scope.line_comment_prefixes();
5047            for delimiter in delimiters {
5048                if *self
5049                    .chars_at(Point::new(row.0, indent.len() as u32))
5050                    .take(delimiter.chars().count())
5051                    .collect::<String>()
5052                    .as_str()
5053                    == **delimiter
5054                {
5055                    indent.push_str(delimiter);
5056                    break;
5057                }
5058            }
5059        }
5060
5061        indent
5062    }
5063
5064    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5065    where
5066        T: ToOffset,
5067    {
5068        for char in self.reversed_chars_at(position) {
5069            if !char.is_whitespace() {
5070                return false;
5071            }
5072            if char == '\n' {
5073                return true;
5074            }
5075        }
5076        true
5077    }
5078
5079    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5080        while row.0 > 0 {
5081            row.0 -= 1;
5082            if !self.is_line_blank(row) {
5083                return Some(row);
5084            }
5085        }
5086        None
5087    }
5088
5089    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5090        if let Some((_, range)) = self.buffer_line_for_row(row) {
5091            range.end.column - range.start.column
5092        } else {
5093            0
5094        }
5095    }
5096
5097    pub fn buffer_line_for_row(
5098        &self,
5099        row: MultiBufferRow,
5100    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5101        let mut cursor = self.cursor::<Point, Point>();
5102        let point = Point::new(row.0, 0);
5103        cursor.seek(&point);
5104        let region = cursor.region()?;
5105        let overshoot = point.min(region.range.end) - region.range.start;
5106        let buffer_point = region.buffer_range.start + overshoot;
5107        if buffer_point.row > region.buffer_range.end.row {
5108            return None;
5109        }
5110        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5111        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5112            .min(region.buffer_range.end);
5113        Some((region.buffer, line_start..line_end))
5114    }
5115
5116    pub fn max_point(&self) -> Point {
5117        self.text_summary().lines
5118    }
5119
5120    pub fn max_row(&self) -> MultiBufferRow {
5121        MultiBufferRow(self.text_summary().lines.row)
5122    }
5123
5124    pub fn text_summary(&self) -> MBTextSummary {
5125        self.diff_transforms.summary().output
5126    }
5127
5128    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5129    where
5130        MBD: MultiBufferDimension + AddAssign,
5131        O: ToOffset,
5132    {
5133        let range = range.start.to_offset(self)..range.end.to_offset(self);
5134        let mut cursor = self
5135            .diff_transforms
5136            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5137        cursor.seek(&range.start, Bias::Right);
5138
5139        let Some(first_transform) = cursor.item() else {
5140            return MBD::from_summary(&MBTextSummary::default());
5141        };
5142
5143        let diff_transform_start = cursor.start().0;
5144        let diff_transform_end = cursor.end().0;
5145        let diff_start = range.start;
5146        let start_overshoot = diff_start - diff_transform_start;
5147        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5148
5149        let mut result = match first_transform {
5150            DiffTransform::BufferContent { .. } => {
5151                let excerpt_start = cursor.start().1 + start_overshoot;
5152                let excerpt_end = cursor.start().1 + end_overshoot;
5153                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5154            }
5155            DiffTransform::DeletedHunk {
5156                buffer_id,
5157                base_text_byte_range,
5158                has_trailing_newline,
5159                ..
5160            } => {
5161                let buffer_start = base_text_byte_range.start + start_overshoot;
5162                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5163                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5164                    panic!("{:?} is in non-existent deleted hunk", range.start)
5165                };
5166
5167                let include_trailing_newline =
5168                    *has_trailing_newline && range.end >= diff_transform_end;
5169                if include_trailing_newline {
5170                    buffer_end -= 1;
5171                }
5172
5173                let mut summary = base_text
5174                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5175
5176                if include_trailing_newline {
5177                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5178                        &TextSummary::newline(),
5179                    ))
5180                }
5181
5182                let mut result = MBD::default();
5183                result.add_text_dim(&summary);
5184                result
5185            }
5186        };
5187        if range.end < diff_transform_end {
5188            return result;
5189        }
5190
5191        cursor.next();
5192        result.add_mb_text_summary(
5193            &cursor
5194                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5195                .0,
5196        );
5197
5198        let Some(last_transform) = cursor.item() else {
5199            return result;
5200        };
5201
5202        let overshoot = range.end - cursor.start().0;
5203        let suffix = match last_transform {
5204            DiffTransform::BufferContent { .. } => {
5205                let end = cursor.start().1 + overshoot;
5206                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5207            }
5208            DiffTransform::DeletedHunk {
5209                base_text_byte_range,
5210                buffer_id,
5211                has_trailing_newline,
5212                ..
5213            } => {
5214                let buffer_end = base_text_byte_range.start + overshoot;
5215                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5216                    panic!("{:?} is in non-existent deleted hunk", range.end)
5217                };
5218
5219                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5220                    base_text_byte_range.start..buffer_end,
5221                );
5222                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5223                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5224                        &TextSummary::from("\n"),
5225                    ))
5226                }
5227
5228                let mut result = MBD::default();
5229                result.add_text_dim(&suffix);
5230                result
5231            }
5232        };
5233
5234        result += suffix;
5235        result
5236    }
5237
5238    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5239    where
5240        MBD: MultiBufferDimension + AddAssign,
5241    {
5242        let mut summary = MBD::default();
5243        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5244        cursor.seek(&range.start, Bias::Right);
5245        if let Some(excerpt) = cursor.item() {
5246            let mut end_before_newline = cursor.end();
5247            if excerpt.has_trailing_newline {
5248                end_before_newline -= 1;
5249            }
5250
5251            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5252            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5253            let end_in_excerpt =
5254                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5255            summary.add_text_dim(
5256                &excerpt
5257                    .buffer
5258                    .text_summary_for_range::<MBD::TextDimension, _>(
5259                        start_in_excerpt..end_in_excerpt,
5260                    ),
5261            );
5262
5263            if range.end > end_before_newline {
5264                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5265            }
5266
5267            cursor.next();
5268        }
5269
5270        if range.end > *cursor.start() {
5271            summary += cursor
5272                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5273                .0;
5274            if let Some(excerpt) = cursor.item() {
5275                range.end = cmp::max(*cursor.start(), range.end);
5276
5277                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5278                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5279                summary.add_text_dim(
5280                    &excerpt
5281                        .buffer
5282                        .text_summary_for_range::<MBD::TextDimension, _>(
5283                            excerpt_start..end_in_excerpt,
5284                        ),
5285                );
5286            }
5287        }
5288
5289        summary
5290    }
5291
5292    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5293    where
5294        MBD: MultiBufferDimension
5295            + Ord
5296            + Sub<Output = MBD::TextDimension>
5297            + Sub<MBD::TextDimension, Output = MBD>
5298            + AddAssign<MBD::TextDimension>
5299            + Add<MBD::TextDimension, Output = MBD>,
5300        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5301    {
5302        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5303        let locator = self.excerpt_locator_for_id(excerpt_id);
5304        let (start, _, mut item) = self
5305            .excerpts
5306            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5307        let mut start = MBD::from_summary(&start.text);
5308        if item.is_none() && excerpt_id == ExcerptId::max() {
5309            item = self.excerpts.last();
5310            if let Some(last_summary) = self.excerpts.last_summary() {
5311                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5312            }
5313        }
5314
5315        if self.diff_transforms.is_empty() {
5316            let excerpt_start_position = ExcerptDimension(start);
5317            if let Some(excerpt) = item {
5318                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5319                    return excerpt_start_position.0;
5320                }
5321                let excerpt_buffer_start = excerpt
5322                    .range
5323                    .context
5324                    .start
5325                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5326                let excerpt_buffer_end = excerpt
5327                    .range
5328                    .context
5329                    .end
5330                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5331                let buffer_summary = anchor
5332                    .text_anchor
5333                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5334                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5335                let mut position = excerpt_start_position;
5336                if summary > excerpt_buffer_start {
5337                    position += summary - excerpt_buffer_start;
5338                }
5339
5340                position.0
5341            } else {
5342                excerpt_start_position.0
5343            }
5344        } else {
5345            let mut diff_transforms_cursor = self
5346                .diff_transforms
5347                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5348            diff_transforms_cursor.next();
5349
5350            let excerpt_start_position = ExcerptDimension(start);
5351            if let Some(excerpt) = item {
5352                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5353                    return self.resolve_summary_for_anchor(
5354                        &Anchor::min(),
5355                        excerpt_start_position,
5356                        &mut diff_transforms_cursor,
5357                    );
5358                }
5359                let excerpt_buffer_start = excerpt
5360                    .range
5361                    .context
5362                    .start
5363                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5364                let excerpt_buffer_end = excerpt
5365                    .range
5366                    .context
5367                    .end
5368                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5369                let buffer_summary = anchor
5370                    .text_anchor
5371                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5372                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5373                let mut position = excerpt_start_position;
5374                if summary > excerpt_buffer_start {
5375                    position += summary - excerpt_buffer_start;
5376                }
5377
5378                if diff_transforms_cursor.start().0 < position {
5379                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5380                }
5381                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5382            } else {
5383                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5384                self.resolve_summary_for_anchor(
5385                    &Anchor::max(),
5386                    excerpt_start_position,
5387                    &mut diff_transforms_cursor,
5388                )
5389            }
5390        }
5391    }
5392
5393    fn resolve_summary_for_anchor<MBD>(
5394        &self,
5395        anchor: &Anchor,
5396        excerpt_position: ExcerptDimension<MBD>,
5397        diff_transforms: &mut Cursor<
5398            DiffTransform,
5399            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5400        >,
5401    ) -> MBD
5402    where
5403        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5404    {
5405        loop {
5406            let transform_end_position = diff_transforms.end().0;
5407            let at_transform_end =
5408                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5409            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5410                diff_transforms.next();
5411                continue;
5412            }
5413
5414            let mut position = diff_transforms.start().1;
5415            match diff_transforms.item() {
5416                Some(DiffTransform::DeletedHunk {
5417                    buffer_id,
5418                    base_text_byte_range,
5419                    ..
5420                }) => {
5421                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5422                        && let Some(base_text) =
5423                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5424                        && diff_base_anchor.is_valid(&base_text)
5425                    {
5426                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5427                        if base_text_offset >= base_text_byte_range.start
5428                            && base_text_offset <= base_text_byte_range.end
5429                        {
5430                            let position_in_hunk = base_text
5431                                .text_summary_for_range::<MBD::TextDimension, _>(
5432                                    base_text_byte_range.start..base_text_offset,
5433                                );
5434                            position.0.add_text_dim(&position_in_hunk);
5435                        } else if at_transform_end {
5436                            diff_transforms.next();
5437                            continue;
5438                        }
5439                    }
5440                }
5441                _ => {
5442                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5443                        diff_transforms.next();
5444                        continue;
5445                    }
5446                    let overshoot = excerpt_position - diff_transforms.start().0;
5447                    position += overshoot;
5448                }
5449            }
5450
5451            return position.0;
5452        }
5453    }
5454
5455    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5456        let mut cursor = self
5457            .excerpts
5458            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5459        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5460
5461        cursor.seek(&Some(locator), Bias::Left);
5462        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5463            cursor.prev();
5464        }
5465
5466        let mut position = cursor.start().1;
5467        if let Some(excerpt) = cursor.item()
5468            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5469        {
5470            let excerpt_buffer_start = excerpt
5471                .buffer
5472                .offset_for_anchor(&excerpt.range.context.start);
5473            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5474            let buffer_position = cmp::min(
5475                excerpt_buffer_end,
5476                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5477            );
5478            if buffer_position > excerpt_buffer_start {
5479                position += buffer_position - excerpt_buffer_start;
5480            }
5481        }
5482        position
5483    }
5484
5485    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5486        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5487            excerpt_id = *replacement;
5488        }
5489        excerpt_id
5490    }
5491
5492    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5493    where
5494        MBD: MultiBufferDimension
5495            + Ord
5496            + Sub<Output = MBD::TextDimension>
5497            + AddAssign<MBD::TextDimension>,
5498        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5499        I: 'a + IntoIterator<Item = &'a Anchor>,
5500    {
5501        let mut anchors = anchors.into_iter().peekable();
5502        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5503        let mut diff_transforms_cursor = self
5504            .diff_transforms
5505            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5506        diff_transforms_cursor.next();
5507
5508        let mut summaries = Vec::new();
5509        while let Some(anchor) = anchors.peek() {
5510            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5511
5512            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5513                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5514            });
5515
5516            let locator = self.excerpt_locator_for_id(excerpt_id);
5517            cursor.seek_forward(locator, Bias::Left);
5518            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5519                cursor.prev();
5520            }
5521
5522            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5523            if let Some(excerpt) = cursor.item() {
5524                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5525                    let position = self.resolve_summary_for_anchor(
5526                        &Anchor::min(),
5527                        excerpt_start_position,
5528                        &mut diff_transforms_cursor,
5529                    );
5530                    summaries.extend(excerpt_anchors.map(|_| position));
5531                    continue;
5532                }
5533                let excerpt_buffer_start = excerpt
5534                    .range
5535                    .context
5536                    .start
5537                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5538                let excerpt_buffer_end = excerpt
5539                    .range
5540                    .context
5541                    .end
5542                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5543                for (buffer_summary, anchor) in excerpt
5544                    .buffer
5545                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5546                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5547                    )
5548                {
5549                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5550                    let mut position = excerpt_start_position;
5551                    if summary > excerpt_buffer_start {
5552                        position += summary - excerpt_buffer_start;
5553                    }
5554
5555                    if diff_transforms_cursor.start().0 < position {
5556                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5557                    }
5558
5559                    summaries.push(self.resolve_summary_for_anchor(
5560                        anchor,
5561                        position,
5562                        &mut diff_transforms_cursor,
5563                    ));
5564                }
5565            } else {
5566                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5567                let position = self.resolve_summary_for_anchor(
5568                    &Anchor::max(),
5569                    excerpt_start_position,
5570                    &mut diff_transforms_cursor,
5571                );
5572                summaries.extend(excerpt_anchors.map(|_| position));
5573            }
5574        }
5575
5576        summaries
5577    }
5578
5579    pub fn dimensions_from_points<'a, MBD>(
5580        &'a self,
5581        points: impl 'a + IntoIterator<Item = Point>,
5582    ) -> impl 'a + Iterator<Item = MBD>
5583    where
5584        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5585    {
5586        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5587        cursor.seek(&DimensionPair {
5588            key: Point::default(),
5589            value: None,
5590        });
5591        let mut points = points.into_iter();
5592        iter::from_fn(move || {
5593            let point = points.next()?;
5594
5595            cursor.seek_forward(&DimensionPair {
5596                key: point,
5597                value: None,
5598            });
5599
5600            if let Some(region) = cursor.region() {
5601                let overshoot = point - region.range.start.key;
5602                let buffer_point = region.buffer_range.start + overshoot;
5603                let mut position = region.range.start.value.unwrap();
5604                position.add_text_dim(
5605                    &region
5606                        .buffer
5607                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5608                );
5609                if point == region.range.end.key && region.has_trailing_newline {
5610                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5611                }
5612                Some(position)
5613            } else {
5614                Some(MBD::from_summary(&self.text_summary()))
5615            }
5616        })
5617    }
5618
5619    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5620    where
5621        I: 'a + IntoIterator<Item = &'a Anchor>,
5622    {
5623        let mut anchors = anchors.into_iter().enumerate().peekable();
5624        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5625        cursor.next();
5626
5627        let mut result = Vec::new();
5628
5629        while let Some((_, anchor)) = anchors.peek() {
5630            let old_excerpt_id = anchor.excerpt_id;
5631
5632            // Find the location where this anchor's excerpt should be.
5633            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5634            cursor.seek_forward(&Some(old_locator), Bias::Left);
5635
5636            let next_excerpt = cursor.item();
5637            let prev_excerpt = cursor.prev_item();
5638
5639            // Process all of the anchors for this excerpt.
5640            while let Some((anchor_ix, &anchor)) =
5641                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5642            {
5643                let mut anchor = anchor;
5644
5645                // Leave min and max anchors unchanged if invalid or
5646                // if the old excerpt still exists at this location
5647                let mut kept_position = next_excerpt
5648                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5649                    || old_excerpt_id == ExcerptId::max()
5650                    || old_excerpt_id == ExcerptId::min();
5651
5652                // If the old excerpt no longer exists at this location, then attempt to
5653                // find an equivalent position for this anchor in an adjacent excerpt.
5654                if !kept_position {
5655                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5656                        if excerpt.contains(&anchor) {
5657                            anchor.excerpt_id = excerpt.id;
5658                            kept_position = true;
5659                            break;
5660                        }
5661                    }
5662                }
5663
5664                // If there's no adjacent excerpt that contains the anchor's position,
5665                // then report that the anchor has lost its position.
5666                if !kept_position {
5667                    anchor = if let Some(excerpt) = next_excerpt {
5668                        let mut text_anchor = excerpt
5669                            .range
5670                            .context
5671                            .start
5672                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5673                        if text_anchor
5674                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5675                            .is_gt()
5676                        {
5677                            text_anchor = excerpt.range.context.end;
5678                        }
5679                        Anchor::in_buffer(excerpt.id, text_anchor)
5680                    } else if let Some(excerpt) = prev_excerpt {
5681                        let mut text_anchor = excerpt
5682                            .range
5683                            .context
5684                            .end
5685                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5686                        if text_anchor
5687                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5688                            .is_lt()
5689                        {
5690                            text_anchor = excerpt.range.context.start;
5691                        }
5692                        Anchor::in_buffer(excerpt.id, text_anchor)
5693                    } else if anchor.text_anchor.bias == Bias::Left {
5694                        Anchor::min()
5695                    } else {
5696                        Anchor::max()
5697                    };
5698                }
5699
5700                result.push((anchor_ix, anchor, kept_position));
5701            }
5702        }
5703        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5704        result
5705    }
5706
5707    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5708        self.anchor_at(position, Bias::Left)
5709    }
5710
5711    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5712        self.anchor_at(position, Bias::Right)
5713    }
5714
5715    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5716        let offset = position.to_offset(self);
5717
5718        // Find the given position in the diff transforms. Determine the corresponding
5719        // offset in the excerpts, and whether the position is within a deleted hunk.
5720        let mut diff_transforms = self
5721            .diff_transforms
5722            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5723        diff_transforms.seek(&offset, Bias::Right);
5724
5725        if offset == diff_transforms.start().0
5726            && bias == Bias::Left
5727            && let Some(prev_item) = diff_transforms.prev_item()
5728            && let DiffTransform::DeletedHunk { .. } = prev_item
5729        {
5730            diff_transforms.prev();
5731        }
5732        let offset_in_transform = offset - diff_transforms.start().0;
5733        let mut excerpt_offset = diff_transforms.start().1;
5734        let mut diff_base_anchor = None;
5735        if let Some(DiffTransform::DeletedHunk {
5736            buffer_id,
5737            base_text_byte_range,
5738            has_trailing_newline,
5739            ..
5740        }) = diff_transforms.item()
5741        {
5742            let diff = self.diffs.get(buffer_id).expect("missing diff");
5743            if offset_in_transform > base_text_byte_range.len() {
5744                debug_assert!(*has_trailing_newline);
5745                bias = Bias::Right;
5746            } else {
5747                diff_base_anchor = Some(
5748                    diff.base_text()
5749                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5750                );
5751                bias = Bias::Left;
5752            }
5753        } else {
5754            excerpt_offset += MultiBufferOffset(offset_in_transform);
5755        };
5756
5757        let mut excerpts = self
5758            .excerpts
5759            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5760        excerpts.seek(&excerpt_offset, Bias::Right);
5761        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5762            excerpts.prev();
5763        }
5764        if let Some(excerpt) = excerpts.item() {
5765            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5766            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5767                overshoot -= 1;
5768                bias = Bias::Right;
5769            }
5770
5771            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5772            let text_anchor =
5773                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5774            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5775            match diff_base_anchor {
5776                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5777                None => anchor,
5778            }
5779        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5780        {
5781            Anchor::min()
5782        } else {
5783            Anchor::max()
5784        }
5785    }
5786
5787    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5788    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5789        let (excerpt, buffer, _) = self.as_singleton()?;
5790        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5791            Some(Anchor::in_buffer(*excerpt, text_anchor))
5792        } else {
5793            None
5794        }
5795    }
5796
5797    /// Returns an anchor for the given excerpt and text anchor,
5798    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5799    pub fn anchor_range_in_excerpt(
5800        &self,
5801        excerpt_id: ExcerptId,
5802        text_anchor: Range<text::Anchor>,
5803    ) -> Option<Range<Anchor>> {
5804        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5805
5806        Some(
5807            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5808                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5809        )
5810    }
5811
5812    /// Returns an anchor for the given excerpt and text anchor,
5813    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5814    pub fn anchor_in_excerpt(
5815        &self,
5816        excerpt_id: ExcerptId,
5817        text_anchor: text::Anchor,
5818    ) -> Option<Anchor> {
5819        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5820        Self::anchor_in_excerpt_(excerpt, text_anchor)
5821    }
5822
5823    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5824    pub fn anchors_in_excerpt(
5825        &self,
5826        excerpt_id: ExcerptId,
5827        text_anchors: impl IntoIterator<Item = text::Anchor>,
5828    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5829        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5830        Some(
5831            text_anchors
5832                .into_iter()
5833                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5834        )
5835    }
5836
5837    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5838        match text_anchor.buffer_id {
5839            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5840            Some(_) => return None,
5841            None if text_anchor.is_max() || text_anchor.is_min() => {
5842                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5843            }
5844            None => return None,
5845        }
5846
5847        let context = &excerpt.range.context;
5848        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5849            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5850        {
5851            return None;
5852        }
5853
5854        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5855    }
5856
5857    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5858        Some(self.excerpt(excerpt_id)?.range.context.clone())
5859    }
5860
5861    pub fn excerpt_range_for_excerpt(
5862        &self,
5863        excerpt_id: ExcerptId,
5864    ) -> Option<ExcerptRange<text::Anchor>> {
5865        Some(self.excerpt(excerpt_id)?.range.clone())
5866    }
5867
5868    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5869        if anchor.is_min() || anchor.is_max() {
5870            // todo(lw): should be `!self.is_empty()`
5871            true
5872        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5873            excerpt.buffer.can_resolve(&anchor.text_anchor)
5874        } else {
5875            false
5876        }
5877    }
5878
5879    pub fn excerpts(
5880        &self,
5881    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5882        self.excerpts
5883            .iter()
5884            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5885    }
5886
5887    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5888    where
5889        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5890        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5891    {
5892        let excerpts = self.excerpts.cursor(());
5893        let diff_transforms = self.diff_transforms.cursor(());
5894        MultiBufferCursor {
5895            excerpts,
5896            diff_transforms,
5897            diffs: &self.diffs,
5898            cached_region: OnceCell::new(),
5899        }
5900    }
5901
5902    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5903        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5904        let mut excerpts = self
5905            .excerpts
5906            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5907        excerpts.seek(&Some(start_locator), Bias::Left);
5908        excerpts.prev();
5909
5910        let mut diff_transforms = self
5911            .diff_transforms
5912            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5913        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5914        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5915            diff_transforms.next();
5916        }
5917
5918        let excerpt = excerpts.item()?;
5919        Some(MultiBufferExcerpt {
5920            excerpt,
5921            offset: diff_transforms.start().output_dimension.0,
5922            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5923            excerpt_offset: excerpts.start().1,
5924            diff_transforms,
5925        })
5926    }
5927
5928    pub fn excerpt_boundaries_in_range<R, T>(
5929        &self,
5930        range: R,
5931    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5932    where
5933        R: RangeBounds<T>,
5934        T: ToOffset,
5935    {
5936        let start_offset;
5937        let start = match range.start_bound() {
5938            Bound::Included(start) => {
5939                start_offset = start.to_offset(self);
5940                Bound::Included(start_offset)
5941            }
5942            Bound::Excluded(_) => {
5943                panic!("not supported")
5944            }
5945            Bound::Unbounded => {
5946                start_offset = MultiBufferOffset::ZERO;
5947                Bound::Unbounded
5948            }
5949        };
5950        let end = match range.end_bound() {
5951            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5952            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5953            Bound::Unbounded => Bound::Unbounded,
5954        };
5955        let bounds = (start, end);
5956        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5957        cursor.seek(&DimensionPair {
5958            key: start_offset,
5959            value: None,
5960        });
5961
5962        if cursor
5963            .fetch_excerpt_with_range()
5964            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5965        {
5966            cursor.prev_excerpt();
5967        } else {
5968            cursor.seek_to_start_of_current_excerpt();
5969        }
5970        let mut prev_region = cursor
5971            .fetch_excerpt_with_range()
5972            .map(|(excerpt, _)| excerpt);
5973
5974        cursor.next_excerpt_forwards();
5975
5976        iter::from_fn(move || {
5977            loop {
5978                if self.singleton {
5979                    return None;
5980                }
5981
5982                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5983                cursor.next_excerpt_forwards();
5984                if !bounds.contains(&next_range.start.key) {
5985                    prev_region = Some(next_excerpt);
5986                    continue;
5987                }
5988
5989                let next_region_start = next_range.start.value.unwrap();
5990                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5991                    range.start.value.unwrap()
5992                } else {
5993                    self.max_point()
5994                };
5995
5996                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5997                    id: region.id,
5998                    buffer: region.buffer.clone(),
5999                    buffer_id: region.buffer_id,
6000                    range: region.range.clone(),
6001                    end_row: MultiBufferRow(next_region_start.row),
6002                });
6003
6004                let next = ExcerptInfo {
6005                    id: next_excerpt.id,
6006                    buffer: next_excerpt.buffer.clone(),
6007                    buffer_id: next_excerpt.buffer_id,
6008                    range: next_excerpt.range.clone(),
6009                    end_row: if next_excerpt.has_trailing_newline {
6010                        MultiBufferRow(next_region_end.row - 1)
6011                    } else {
6012                        MultiBufferRow(next_region_end.row)
6013                    },
6014                };
6015
6016                let row = MultiBufferRow(next_region_start.row);
6017
6018                prev_region = Some(next_excerpt);
6019
6020                return Some(ExcerptBoundary { row, prev, next });
6021            }
6022        })
6023    }
6024
6025    pub fn edit_count(&self) -> usize {
6026        self.edit_count
6027    }
6028
6029    pub fn non_text_state_update_count(&self) -> usize {
6030        self.non_text_state_update_count
6031    }
6032
6033    /// Returns the smallest enclosing bracket ranges containing the given range or
6034    /// None if no brackets contain range or the range is not contained in a single
6035    /// excerpt
6036    ///
6037    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6038    #[ztracing::instrument(skip_all)]
6039    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6040        &self,
6041        range: Range<T>,
6042        range_filter: Option<
6043            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6044        >,
6045    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6046        let range = range.start.to_offset(self)..range.end.to_offset(self);
6047        let mut excerpt = self.excerpt_containing(range.clone())?;
6048        let buffer = excerpt.buffer();
6049        let excerpt_buffer_range = excerpt.buffer_range();
6050
6051        // Filter to ranges contained in the excerpt
6052        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6053            excerpt_buffer_range.contains(&BufferOffset(open.start))
6054                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6055                && range_filter.is_none_or(|filter| {
6056                    filter(
6057                        buffer,
6058                        BufferOffset(open.start)..BufferOffset(close.end),
6059                        BufferOffset(close.start)..BufferOffset(close.end),
6060                    )
6061                })
6062        };
6063
6064        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6065            excerpt.map_range_to_buffer(range),
6066            Some(&range_filter),
6067        )?;
6068
6069        Some((
6070            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6071            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6072        ))
6073    }
6074
6075    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6076    /// not contained in a single excerpt
6077    pub fn enclosing_bracket_ranges<T: ToOffset>(
6078        &self,
6079        range: Range<T>,
6080    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6081    {
6082        let range = range.start.to_offset(self)..range.end.to_offset(self);
6083        let mut excerpt = self.excerpt_containing(range.clone())?;
6084
6085        Some(
6086            excerpt
6087                .buffer()
6088                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6089                .filter_map(move |pair| {
6090                    let open_range =
6091                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6092                    let close_range =
6093                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6094                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6095                        Some((
6096                            excerpt.map_range_from_buffer(open_range),
6097                            excerpt.map_range_from_buffer(close_range),
6098                        ))
6099                    } else {
6100                        None
6101                    }
6102                }),
6103        )
6104    }
6105
6106    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6107    /// not contained in a single excerpt
6108    pub fn text_object_ranges<T: ToOffset>(
6109        &self,
6110        range: Range<T>,
6111        options: TreeSitterOptions,
6112    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6113        let range = range.start.to_offset(self)..range.end.to_offset(self);
6114        self.excerpt_containing(range.clone())
6115            .map(|mut excerpt| {
6116                excerpt
6117                    .buffer()
6118                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6119                    .filter_map(move |(range, text_object)| {
6120                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6121                        if excerpt.contains_buffer_range(range.clone()) {
6122                            Some((excerpt.map_range_from_buffer(range), text_object))
6123                        } else {
6124                            None
6125                        }
6126                    })
6127            })
6128            .into_iter()
6129            .flatten()
6130    }
6131
6132    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6133    /// not contained in a single excerpt
6134    pub fn bracket_ranges<T: ToOffset>(
6135        &self,
6136        range: Range<T>,
6137    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6138    {
6139        let range = range.start.to_offset(self)..range.end.to_offset(self);
6140        let mut excerpt = self.excerpt_containing(range.clone())?;
6141        Some(
6142            excerpt
6143                .buffer()
6144                .bracket_ranges(excerpt.map_range_to_buffer(range))
6145                .filter_map(move |pair| {
6146                    let open_range =
6147                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6148                    let close_range =
6149                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6150                    excerpt
6151                        .contains_buffer_range(open_range.start..close_range.end)
6152                        .then(|| BracketMatch {
6153                            open_range: excerpt.map_range_from_buffer(open_range),
6154                            close_range: excerpt.map_range_from_buffer(close_range),
6155                            color_index: pair.color_index,
6156                            newline_only: pair.newline_only,
6157                            syntax_layer_depth: pair.syntax_layer_depth,
6158                        })
6159                })
6160                .map(BracketMatch::bracket_ranges),
6161        )
6162    }
6163
6164    pub fn redacted_ranges<'a, T: ToOffset>(
6165        &'a self,
6166        range: Range<T>,
6167        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6168    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6169        let range = range.start.to_offset(self)..range.end.to_offset(self);
6170        self.lift_buffer_metadata(range, move |buffer, range| {
6171            if redaction_enabled(buffer.file()) {
6172                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6173            } else {
6174                None
6175            }
6176        })
6177        .map(|(range, _, _)| range)
6178    }
6179
6180    pub fn runnable_ranges(
6181        &self,
6182        range: Range<Anchor>,
6183    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6184        let range = range.start.to_offset(self)..range.end.to_offset(self);
6185        self.lift_buffer_metadata(range, move |buffer, range| {
6186            Some(
6187                buffer
6188                    .runnable_ranges(range.clone())
6189                    .filter(move |runnable| {
6190                        runnable.run_range.start >= range.start
6191                            && runnable.run_range.end < range.end
6192                    })
6193                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6194            )
6195        })
6196        .map(|(run_range, runnable, _)| (run_range, runnable))
6197    }
6198
6199    pub fn line_indents(
6200        &self,
6201        start_row: MultiBufferRow,
6202        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6203    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6204        let max_point = self.max_point();
6205        let mut cursor = self.cursor::<Point, Point>();
6206        cursor.seek(&Point::new(start_row.0, 0));
6207        iter::from_fn(move || {
6208            let mut region = cursor.region()?;
6209            while !buffer_filter(&region.excerpt.buffer) {
6210                cursor.next();
6211                region = cursor.region()?;
6212            }
6213            let region = cursor.region()?;
6214            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6215            let buffer_start_row =
6216                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6217
6218            let buffer_end_row = if region.is_main_buffer
6219                && (region.has_trailing_newline || region.range.end == max_point)
6220            {
6221                region.buffer_range.end.row
6222            } else {
6223                region.buffer_range.end.row.saturating_sub(1)
6224            };
6225
6226            let line_indents = region
6227                .buffer
6228                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6229            let region_buffer_row = region.buffer_range.start.row;
6230            let region_row = region.range.start.row;
6231            let region_buffer = &region.excerpt.buffer;
6232            cursor.next();
6233            Some(line_indents.map(move |(buffer_row, indent)| {
6234                let row = region_row + (buffer_row - region_buffer_row);
6235                (MultiBufferRow(row), indent, region_buffer.as_ref())
6236            }))
6237        })
6238        .flatten()
6239    }
6240
6241    pub fn reversed_line_indents(
6242        &self,
6243        end_row: MultiBufferRow,
6244        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6245    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6246        let max_point = self.max_point();
6247        let mut cursor = self.cursor::<Point, Point>();
6248        cursor.seek(&Point::new(end_row.0, 0));
6249        iter::from_fn(move || {
6250            let mut region = cursor.region()?;
6251            while !buffer_filter(&region.excerpt.buffer) {
6252                cursor.prev();
6253                region = cursor.region()?;
6254            }
6255            let region = cursor.region()?;
6256
6257            let buffer_start_row = region.buffer_range.start.row;
6258            let buffer_end_row = if region.is_main_buffer
6259                && (region.has_trailing_newline || region.range.end == max_point)
6260            {
6261                region.buffer_range.end.row + 1
6262            } else {
6263                region.buffer_range.end.row
6264            };
6265
6266            let overshoot = end_row.0 - region.range.start.row;
6267            let buffer_end_row =
6268                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6269
6270            let line_indents = region
6271                .buffer
6272                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6273            let region_buffer_row = region.buffer_range.start.row;
6274            let region_row = region.range.start.row;
6275            let region_buffer = &region.excerpt.buffer;
6276            cursor.prev();
6277            Some(line_indents.map(move |(buffer_row, indent)| {
6278                let row = region_row + (buffer_row - region_buffer_row);
6279                (MultiBufferRow(row), indent, region_buffer.as_ref())
6280            }))
6281        })
6282        .flatten()
6283    }
6284
6285    pub async fn enclosing_indent(
6286        &self,
6287        mut target_row: MultiBufferRow,
6288    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6289        let max_row = MultiBufferRow(self.max_point().row);
6290        if target_row >= max_row {
6291            return None;
6292        }
6293
6294        let mut target_indent = self.line_indent_for_row(target_row);
6295
6296        // If the current row is at the start of an indented block, we want to return this
6297        // block as the enclosing indent.
6298        if !target_indent.is_line_empty() && target_row < max_row {
6299            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6300            if !next_line_indent.is_line_empty()
6301                && target_indent.raw_len() < next_line_indent.raw_len()
6302            {
6303                target_indent = next_line_indent;
6304                target_row.0 += 1;
6305            }
6306        }
6307
6308        const SEARCH_ROW_LIMIT: u32 = 25000;
6309        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6310        const YIELD_INTERVAL: u32 = 100;
6311
6312        let mut accessed_row_counter = 0;
6313
6314        // If there is a blank line at the current row, search for the next non indented lines
6315        if target_indent.is_line_empty() {
6316            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6317            let end =
6318                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6319
6320            let mut non_empty_line_above = None;
6321            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6322                if row < start {
6323                    break;
6324                }
6325                accessed_row_counter += 1;
6326                if accessed_row_counter == YIELD_INTERVAL {
6327                    accessed_row_counter = 0;
6328                    yield_now().await;
6329                }
6330                if !indent.is_line_empty() {
6331                    non_empty_line_above = Some((row, indent));
6332                    break;
6333                }
6334            }
6335
6336            let mut non_empty_line_below = None;
6337            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6338                if row > end {
6339                    break;
6340                }
6341                accessed_row_counter += 1;
6342                if accessed_row_counter == YIELD_INTERVAL {
6343                    accessed_row_counter = 0;
6344                    yield_now().await;
6345                }
6346                if !indent.is_line_empty() {
6347                    non_empty_line_below = Some((row, indent));
6348                    break;
6349                }
6350            }
6351
6352            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6353                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6354                    if above_indent.raw_len() >= below_indent.raw_len() {
6355                        (above_row, above_indent)
6356                    } else {
6357                        (below_row, below_indent)
6358                    }
6359                }
6360                (Some(above), None) => above,
6361                (None, Some(below)) => below,
6362                _ => return None,
6363            };
6364
6365            target_indent = indent;
6366            target_row = row;
6367        }
6368
6369        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6370        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6371
6372        let mut start_indent = None;
6373        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6374            if row < start {
6375                break;
6376            }
6377            accessed_row_counter += 1;
6378            if accessed_row_counter == YIELD_INTERVAL {
6379                accessed_row_counter = 0;
6380                yield_now().await;
6381            }
6382            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6383                start_indent = Some((row, indent));
6384                break;
6385            }
6386        }
6387        let (start_row, start_indent_size) = start_indent?;
6388
6389        let mut end_indent = (end, None);
6390        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6391            if row > end {
6392                break;
6393            }
6394            accessed_row_counter += 1;
6395            if accessed_row_counter == YIELD_INTERVAL {
6396                accessed_row_counter = 0;
6397                yield_now().await;
6398            }
6399            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6400                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6401                break;
6402            }
6403        }
6404        let (end_row, end_indent_size) = end_indent;
6405
6406        let indent = if let Some(end_indent_size) = end_indent_size {
6407            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6408                start_indent_size
6409            } else {
6410                end_indent_size
6411            }
6412        } else {
6413            start_indent_size
6414        };
6415
6416        Some((start_row..end_row, indent))
6417    }
6418
6419    pub fn indent_guides_in_range<T: ToPoint>(
6420        &self,
6421        range: Range<T>,
6422        ignore_disabled_for_language: bool,
6423        cx: &App,
6424    ) -> impl Iterator<Item = IndentGuide> {
6425        let range = range.start.to_point(self)..range.end.to_point(self);
6426        let start_row = MultiBufferRow(range.start.row);
6427        let end_row = MultiBufferRow(range.end.row);
6428
6429        let mut row_indents = self.line_indents(start_row, |buffer| {
6430            let settings =
6431                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6432            settings.indent_guides.enabled || ignore_disabled_for_language
6433        });
6434
6435        let mut result = Vec::new();
6436        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6437
6438        let mut prev_settings = None;
6439        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6440            if first_row > end_row {
6441                break;
6442            }
6443            let current_depth = indent_stack.len() as u32;
6444
6445            // Avoid retrieving the language settings repeatedly for every buffer row.
6446            if let Some((prev_buffer_id, _)) = &prev_settings
6447                && prev_buffer_id != &buffer.remote_id()
6448            {
6449                prev_settings.take();
6450            }
6451            let settings = &prev_settings
6452                .get_or_insert_with(|| {
6453                    (
6454                        buffer.remote_id(),
6455                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6456                    )
6457                })
6458                .1;
6459            let tab_size = settings.tab_size.get();
6460
6461            // When encountering empty, continue until found useful line indent
6462            // then add to the indent stack with the depth found
6463            let mut found_indent = false;
6464            let mut last_row = first_row;
6465            if line_indent.is_line_blank() {
6466                while !found_indent {
6467                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6468                        break;
6469                    };
6470                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6471                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6472                        break;
6473                    }
6474
6475                    if new_line_indent.is_line_blank() {
6476                        continue;
6477                    }
6478                    last_row = target_row.min(end_row);
6479                    line_indent = new_line_indent;
6480                    found_indent = true;
6481                    break;
6482                }
6483            } else {
6484                found_indent = true
6485            }
6486
6487            let depth = if found_indent {
6488                line_indent.len(tab_size) / tab_size
6489            } else {
6490                0
6491            };
6492
6493            match depth.cmp(&current_depth) {
6494                cmp::Ordering::Less => {
6495                    for _ in 0..(current_depth - depth) {
6496                        let mut indent = indent_stack.pop().unwrap();
6497                        if last_row != first_row {
6498                            // In this case, we landed on an empty row, had to seek forward,
6499                            // and discovered that the indent we where on is ending.
6500                            // This means that the last display row must
6501                            // be on line that ends this indent range, so we
6502                            // should display the range up to the first non-empty line
6503                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6504                        }
6505
6506                        result.push(indent)
6507                    }
6508                }
6509                cmp::Ordering::Greater => {
6510                    for next_depth in current_depth..depth {
6511                        indent_stack.push(IndentGuide {
6512                            buffer_id: buffer.remote_id(),
6513                            start_row: first_row,
6514                            end_row: last_row,
6515                            depth: next_depth,
6516                            tab_size,
6517                            settings: settings.indent_guides.clone(),
6518                        });
6519                    }
6520                }
6521                _ => {}
6522            }
6523
6524            for indent in indent_stack.iter_mut() {
6525                indent.end_row = last_row;
6526            }
6527        }
6528
6529        result.extend(indent_stack);
6530        result.into_iter()
6531    }
6532
6533    pub fn trailing_excerpt_update_count(&self) -> usize {
6534        self.trailing_excerpt_update_count
6535    }
6536
6537    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6538        self.point_to_buffer_offset(point)
6539            .and_then(|(buffer, _)| buffer.file())
6540    }
6541
6542    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6543        self.point_to_buffer_offset(offset)
6544            .and_then(|(buffer, offset)| buffer.language_at(offset))
6545    }
6546
6547    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6548        self.excerpts
6549            .first()
6550            .map(|excerpt| &excerpt.buffer)
6551            .map(|buffer| {
6552                language_settings(
6553                    buffer.language().map(|language| language.name()),
6554                    buffer.file(),
6555                    cx,
6556                )
6557            })
6558            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6559    }
6560
6561    pub fn language_settings_at<'a, T: ToOffset>(
6562        &'a self,
6563        point: T,
6564        cx: &'a App,
6565    ) -> Cow<'a, LanguageSettings> {
6566        let mut language = None;
6567        let mut file = None;
6568        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6569            language = buffer.language_at(offset);
6570            file = buffer.file();
6571        }
6572        language_settings(language.map(|l| l.name()), file, cx)
6573    }
6574
6575    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6576        self.point_to_buffer_offset(point)
6577            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6578    }
6579
6580    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6581        self.point_to_buffer_offset(point)
6582            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6583            .unwrap_or_default()
6584    }
6585
6586    pub fn language_indent_size_at<T: ToOffset>(
6587        &self,
6588        position: T,
6589        cx: &App,
6590    ) -> Option<IndentSize> {
6591        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6592        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6593    }
6594
6595    pub fn is_dirty(&self) -> bool {
6596        self.is_dirty
6597    }
6598
6599    pub fn has_deleted_file(&self) -> bool {
6600        self.has_deleted_file
6601    }
6602
6603    pub fn has_conflict(&self) -> bool {
6604        self.has_conflict
6605    }
6606
6607    pub fn has_diagnostics(&self) -> bool {
6608        self.excerpts
6609            .iter()
6610            .any(|excerpt| excerpt.buffer.has_diagnostics())
6611    }
6612
6613    pub fn diagnostic_group(
6614        &self,
6615        buffer_id: BufferId,
6616        group_id: usize,
6617    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6618        self.lift_buffer_metadata::<Point, _, _>(
6619            Point::zero()..self.max_point(),
6620            move |buffer, range| {
6621                if buffer.remote_id() != buffer_id {
6622                    return None;
6623                };
6624                Some(
6625                    buffer
6626                        .diagnostics_in_range(range, false)
6627                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6628                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6629                )
6630            },
6631        )
6632        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6633    }
6634
6635    pub fn diagnostics_in_range<'a, MBD>(
6636        &'a self,
6637        range: Range<MBD>,
6638    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6639    where
6640        MBD::TextDimension: 'a
6641            + text::ToOffset
6642            + text::FromAnchor
6643            + Sub<Output = MBD::TextDimension>
6644            + fmt::Debug
6645            + ops::Add<Output = MBD::TextDimension>
6646            + ops::AddAssign
6647            + Ord,
6648        MBD: MultiBufferDimension
6649            + Ord
6650            + Sub<Output = MBD::TextDimension>
6651            + ops::Add<MBD::TextDimension, Output = MBD>
6652            + ops::AddAssign<MBD::TextDimension>
6653            + 'a,
6654    {
6655        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6656            Some(
6657                buffer
6658                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6659                    .map(|entry| (entry.range, entry.diagnostic)),
6660            )
6661        })
6662        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6663    }
6664
6665    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6666        &'a self,
6667        range: Range<MBD>,
6668    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6669    where
6670        MBD: MultiBufferDimension
6671            + Ord
6672            + Sub<Output = MBD::TextDimension>
6673            + ops::Add<MBD::TextDimension, Output = MBD>
6674            + ops::AddAssign<MBD::TextDimension>,
6675        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6676            + ops::Add<Output = MBD::TextDimension>
6677            + text::ToOffset
6678            + text::FromAnchor
6679            + AddAssign<MBD::TextDimension>
6680            + Ord,
6681    {
6682        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6683            Some(
6684                buffer
6685                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6686                    .map(|entry| (entry.range, entry.diagnostic)),
6687            )
6688        })
6689        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6690    }
6691
6692    pub fn syntax_ancestor<T: ToOffset>(
6693        &self,
6694        range: Range<T>,
6695    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6696        let range = range.start.to_offset(self)..range.end.to_offset(self);
6697        let mut excerpt = self.excerpt_containing(range.clone())?;
6698        let node = excerpt
6699            .buffer()
6700            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6701        let node_range = node.byte_range();
6702        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6703        if !excerpt.contains_buffer_range(node_range.clone()) {
6704            return None;
6705        };
6706        Some((node, excerpt.map_range_from_buffer(node_range)))
6707    }
6708
6709    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6710        let (excerpt_id, _, buffer) = self.as_singleton()?;
6711        let outline = buffer.outline(theme);
6712        Some(Outline::new(
6713            outline
6714                .items
6715                .into_iter()
6716                .flat_map(|item| {
6717                    Some(OutlineItem {
6718                        depth: item.depth,
6719                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6720                        source_range_for_text: self
6721                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6722                        text: item.text,
6723                        highlight_ranges: item.highlight_ranges,
6724                        name_ranges: item.name_ranges,
6725                        body_range: item.body_range.and_then(|body_range| {
6726                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6727                        }),
6728                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6729                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6730                        }),
6731                    })
6732                })
6733                .collect(),
6734        ))
6735    }
6736
6737    pub fn symbols_containing<T: ToOffset>(
6738        &self,
6739        offset: T,
6740        theme: Option<&SyntaxTheme>,
6741    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6742        let anchor = self.anchor_before(offset);
6743        let excerpt @ &Excerpt {
6744            id: excerpt_id,
6745            buffer_id,
6746            ref buffer,
6747            ..
6748        } = self.excerpt(anchor.excerpt_id)?;
6749        if cfg!(debug_assertions) {
6750            match anchor.text_anchor.buffer_id {
6751                // we clearly are hitting this according to sentry, but in what situations can this occur?
6752                Some(anchor_buffer_id) => {
6753                    assert_eq!(
6754                        anchor_buffer_id, buffer_id,
6755                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6756                    )
6757                }
6758                None => assert!(anchor.is_max()),
6759            }
6760        };
6761        Some((
6762            buffer_id,
6763            buffer
6764                .symbols_containing(anchor.text_anchor, theme)
6765                .into_iter()
6766                .flat_map(|item| {
6767                    Some(OutlineItem {
6768                        depth: item.depth,
6769                        source_range_for_text: Anchor::range_in_buffer(
6770                            excerpt_id,
6771                            item.source_range_for_text,
6772                        ),
6773                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6774                        text: item.text,
6775                        highlight_ranges: item.highlight_ranges,
6776                        name_ranges: item.name_ranges,
6777                        body_range: item
6778                            .body_range
6779                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6780                        annotation_range: item
6781                            .annotation_range
6782                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6783                    })
6784                })
6785                .collect(),
6786        ))
6787    }
6788
6789    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6790        if id == ExcerptId::min() {
6791            Locator::min_ref()
6792        } else if id == ExcerptId::max() {
6793            Locator::max_ref()
6794        } else {
6795            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6796            if let Some(entry) = item
6797                && entry.id == id
6798            {
6799                return &entry.locator;
6800            }
6801            panic!("invalid excerpt id {id:?}")
6802        }
6803    }
6804
6805    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6806    fn excerpt_locators_for_ids(
6807        &self,
6808        ids: impl IntoIterator<Item = ExcerptId>,
6809    ) -> SmallVec<[Locator; 1]> {
6810        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6811        sorted_ids.sort_unstable();
6812        sorted_ids.dedup();
6813        let mut locators = SmallVec::new();
6814
6815        while sorted_ids.last() == Some(&ExcerptId::max()) {
6816            sorted_ids.pop();
6817            locators.push(Locator::max());
6818        }
6819
6820        let mut sorted_ids = sorted_ids.into_iter().peekable();
6821        locators.extend(
6822            sorted_ids
6823                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6824                .map(|_| Locator::min()),
6825        );
6826
6827        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6828        for id in sorted_ids {
6829            if cursor.seek_forward(&id, Bias::Left) {
6830                locators.push(cursor.item().unwrap().locator.clone());
6831            } else {
6832                panic!("invalid excerpt id {:?}", id);
6833            }
6834        }
6835
6836        locators.sort_unstable();
6837        locators
6838    }
6839
6840    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6841        Some(self.excerpt(excerpt_id)?.buffer_id)
6842    }
6843
6844    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6845        Some(&self.excerpt(excerpt_id)?.buffer)
6846    }
6847
6848    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6849        let mut cursor = self
6850            .excerpts
6851            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6852        let locator = self.excerpt_locator_for_id(excerpt_id);
6853        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6854        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6855            sought_exact = true;
6856            cursor.prev();
6857        } else if excerpt_id == ExcerptId::min() {
6858            sought_exact = true;
6859        }
6860        if sought_exact {
6861            let start = cursor.start().1;
6862            let end = cursor.end().1;
6863            let mut diff_transforms = self
6864                .diff_transforms
6865                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6866            diff_transforms.seek(&start, Bias::Left);
6867            let overshoot = start - diff_transforms.start().0;
6868            let start = diff_transforms.start().1 + overshoot;
6869            diff_transforms.seek(&end, Bias::Right);
6870            let overshoot = end - diff_transforms.start().0;
6871            let end = diff_transforms.start().1 + overshoot;
6872            Some(start.0..end.0)
6873        } else {
6874            None
6875        }
6876    }
6877
6878    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6879    /// to have the latest excerpt id for the one passed in and will also remap
6880    /// `ExcerptId::max()` to the corresponding excertp ID.
6881    ///
6882    /// Callers of this function should generally use the resulting excerpt's `id` field
6883    /// afterwards.
6884    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6885        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6886        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6887        let locator = self.excerpt_locator_for_id(excerpt_id);
6888        cursor.seek(&Some(locator), Bias::Left);
6889        if let Some(excerpt) = cursor.item()
6890            && excerpt.id == excerpt_id
6891        {
6892            return Some(excerpt);
6893        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6894            cursor.prev();
6895            return cursor.item();
6896        }
6897        None
6898    }
6899
6900    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6901    pub fn excerpt_containing<T: ToOffset>(
6902        &self,
6903        range: Range<T>,
6904    ) -> Option<MultiBufferExcerpt<'_>> {
6905        let range = range.start.to_offset(self)..range.end.to_offset(self);
6906        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6907        cursor.seek(&range.start);
6908
6909        let start_excerpt = cursor.excerpt()?;
6910        if range.end != range.start {
6911            cursor.seek_forward(&range.end);
6912            if cursor.excerpt()?.id != start_excerpt.id {
6913                return None;
6914            }
6915        }
6916
6917        cursor.seek_to_start_of_current_excerpt();
6918        let region = cursor.region()?;
6919        let offset = region.range.start;
6920        let buffer_offset = start_excerpt.buffer_start_offset();
6921        let excerpt_offset = *cursor.excerpts.start();
6922        Some(MultiBufferExcerpt {
6923            diff_transforms: cursor.diff_transforms,
6924            excerpt: start_excerpt,
6925            offset,
6926            buffer_offset,
6927            excerpt_offset,
6928        })
6929    }
6930
6931    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6932        if let Some(id) = anchor.text_anchor.buffer_id {
6933            return Some(id);
6934        }
6935        let excerpt = self.excerpt_containing(anchor..anchor)?;
6936        Some(excerpt.buffer_id())
6937    }
6938
6939    pub fn selections_in_range<'a>(
6940        &'a self,
6941        range: &'a Range<Anchor>,
6942        include_local: bool,
6943    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6944        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6945        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6946        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6947        cursor.seek(start_locator, Bias::Left);
6948        cursor
6949            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6950            .flat_map(move |excerpt| {
6951                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6952                if excerpt.id == range.start.excerpt_id {
6953                    query_range.start = range.start.text_anchor;
6954                }
6955                if excerpt.id == range.end.excerpt_id {
6956                    query_range.end = range.end.text_anchor;
6957                }
6958
6959                excerpt
6960                    .buffer
6961                    .selections_in_range(query_range, include_local)
6962                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6963                        selections.map(move |selection| {
6964                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6965                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6966                            if range.start.cmp(&start, self).is_gt() {
6967                                start = range.start;
6968                            }
6969                            if range.end.cmp(&end, self).is_lt() {
6970                                end = range.end;
6971                            }
6972
6973                            (
6974                                replica_id,
6975                                line_mode,
6976                                cursor_shape,
6977                                Selection {
6978                                    id: selection.id,
6979                                    start,
6980                                    end,
6981                                    reversed: selection.reversed,
6982                                    goal: selection.goal,
6983                                },
6984                            )
6985                        })
6986                    })
6987            })
6988    }
6989
6990    pub fn show_headers(&self) -> bool {
6991        self.show_headers
6992    }
6993
6994    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6995        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6996    }
6997
6998    pub fn all_diff_hunks_expanded(&self) -> bool {
6999        self.all_diff_hunks_expanded
7000    }
7001
7002    /// Visually annotates a position or range with the `Debug` representation of a value. The
7003    /// callsite of this function is used as a key - previous annotations will be removed.
7004    #[cfg(debug_assertions)]
7005    #[track_caller]
7006    pub fn debug<V, R>(&self, ranges: &R, value: V)
7007    where
7008        R: debug::ToMultiBufferDebugRanges,
7009        V: std::fmt::Debug,
7010    {
7011        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7012    }
7013
7014    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7015    /// debug annotations with the same key will be removed. The key is also used to determine the
7016    /// annotation's color.
7017    #[cfg(debug_assertions)]
7018    #[track_caller]
7019    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7020    where
7021        K: std::hash::Hash + 'static,
7022        R: debug::ToMultiBufferDebugRanges,
7023        V: std::fmt::Debug,
7024    {
7025        let text_ranges = ranges
7026            .to_multi_buffer_debug_ranges(self)
7027            .into_iter()
7028            .flat_map(|range| {
7029                self.range_to_buffer_ranges(range.start..=range.end)
7030                    .into_iter()
7031                    .map(|(buffer, range, _excerpt_id)| {
7032                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7033                    })
7034            })
7035            .collect();
7036        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7037            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7038        });
7039    }
7040
7041    fn excerpt_edits_for_diff_change(
7042        &self,
7043        buffer_state: &BufferState,
7044        diff_change_range: Range<usize>,
7045    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7046        let mut excerpt_edits = Vec::new();
7047        for locator in &buffer_state.excerpts {
7048            let mut cursor = self
7049                .excerpts
7050                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7051            cursor.seek_forward(&Some(locator), Bias::Left);
7052            if let Some(excerpt) = cursor.item()
7053                && excerpt.locator == *locator
7054            {
7055                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7056                if diff_change_range.end < excerpt_buffer_range.start
7057                    || diff_change_range.start > excerpt_buffer_range.end
7058                {
7059                    continue;
7060                }
7061                let excerpt_start = cursor.start().1;
7062                let excerpt_len = excerpt.text_summary.len;
7063                let diff_change_start_in_excerpt = diff_change_range
7064                    .start
7065                    .saturating_sub(excerpt_buffer_range.start);
7066                let diff_change_end_in_excerpt = diff_change_range
7067                    .end
7068                    .saturating_sub(excerpt_buffer_range.start);
7069                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7070                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7071                excerpt_edits.push(Edit {
7072                    old: edit_start..edit_end,
7073                    new: edit_start..edit_end,
7074                });
7075            }
7076        }
7077        excerpt_edits
7078    }
7079}
7080
7081#[cfg(any(test, feature = "test-support"))]
7082impl MultiBufferSnapshot {
7083    pub fn random_byte_range(
7084        &self,
7085        start_offset: MultiBufferOffset,
7086        rng: &mut impl rand::Rng,
7087    ) -> Range<MultiBufferOffset> {
7088        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7089        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7090        start..end
7091    }
7092
7093    #[cfg(any(test, feature = "test-support"))]
7094    fn check_invariants(&self) {
7095        let excerpts = self.excerpts.items(());
7096        let excerpt_ids = self.excerpt_ids.items(());
7097
7098        for (ix, excerpt) in excerpts.iter().enumerate() {
7099            if ix == 0 {
7100                if excerpt.locator <= Locator::min() {
7101                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7102                }
7103            } else if excerpt.locator <= excerpts[ix - 1].locator {
7104                panic!("excerpts are out-of-order: {:?}", excerpts);
7105            }
7106        }
7107
7108        for (ix, entry) in excerpt_ids.iter().enumerate() {
7109            if ix == 0 {
7110                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7111                    panic!("invalid first excerpt id {:?}", entry.id);
7112                }
7113            } else if entry.id <= excerpt_ids[ix - 1].id {
7114                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7115            }
7116        }
7117
7118        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7119            panic!(
7120                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7121                self.excerpts.summary().text,
7122                self.diff_transforms.summary().input,
7123                self.diff_transforms.items(()),
7124            );
7125        }
7126
7127        let mut prev_transform: Option<&DiffTransform> = None;
7128        for item in self.diff_transforms.iter() {
7129            if let DiffTransform::BufferContent {
7130                summary,
7131                inserted_hunk_info,
7132            } = item
7133            {
7134                if let Some(DiffTransform::BufferContent {
7135                    inserted_hunk_info: prev_inserted_hunk_info,
7136                    ..
7137                }) = prev_transform
7138                    && *inserted_hunk_info == *prev_inserted_hunk_info
7139                {
7140                    panic!(
7141                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7142                        self.diff_transforms.items(())
7143                    );
7144                }
7145                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7146                    panic!("empty buffer content transform");
7147                }
7148            }
7149            prev_transform = Some(item);
7150        }
7151    }
7152}
7153
7154impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7155where
7156    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7157    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7158{
7159    #[instrument(skip_all)]
7160    fn seek(&mut self, position: &MBD) {
7161        let position = OutputDimension(*position);
7162        self.cached_region.take();
7163        self.diff_transforms.seek(&position, Bias::Right);
7164        if self.diff_transforms.item().is_none()
7165            && self.diff_transforms.start().output_dimension == position
7166        {
7167            self.diff_transforms.prev();
7168        }
7169
7170        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7171        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7172            let overshoot = position - self.diff_transforms.start().output_dimension;
7173            excerpt_position += overshoot;
7174        }
7175
7176        self.excerpts.seek(&excerpt_position, Bias::Right);
7177        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7178            self.excerpts.prev();
7179        }
7180    }
7181
7182    fn seek_forward(&mut self, position: &MBD) {
7183        let position = OutputDimension(*position);
7184        self.cached_region.take();
7185        self.diff_transforms.seek_forward(&position, Bias::Right);
7186        if self.diff_transforms.item().is_none()
7187            && self.diff_transforms.start().output_dimension == position
7188        {
7189            self.diff_transforms.prev();
7190        }
7191
7192        let overshoot = position - self.diff_transforms.start().output_dimension;
7193        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7194        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7195            excerpt_position += overshoot;
7196        }
7197
7198        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7199        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7200            self.excerpts.prev();
7201        }
7202    }
7203
7204    fn next_excerpt(&mut self) {
7205        self.excerpts.next();
7206        self.seek_to_start_of_current_excerpt();
7207    }
7208
7209    fn prev_excerpt(&mut self) {
7210        self.excerpts.prev();
7211        self.seek_to_start_of_current_excerpt();
7212    }
7213
7214    fn seek_to_start_of_current_excerpt(&mut self) {
7215        self.cached_region.take();
7216
7217        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7218            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7219            && self.diff_transforms.next_item().is_some()
7220        {
7221            self.diff_transforms.next();
7222        }
7223    }
7224
7225    fn next_excerpt_forwards(&mut self) {
7226        self.excerpts.next();
7227        self.seek_to_start_of_current_excerpt_forward();
7228    }
7229
7230    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7231        self.cached_region.take();
7232
7233        if self
7234            .diff_transforms
7235            .seek_forward(self.excerpts.start(), Bias::Left)
7236            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7237            && self.diff_transforms.next_item().is_some()
7238        {
7239            self.diff_transforms.next();
7240        }
7241    }
7242
7243    fn next(&mut self) {
7244        self.cached_region.take();
7245        match self
7246            .diff_transforms
7247            .end()
7248            .excerpt_dimension
7249            .cmp(&self.excerpts.end())
7250        {
7251            cmp::Ordering::Less => self.diff_transforms.next(),
7252            cmp::Ordering::Greater => self.excerpts.next(),
7253            cmp::Ordering::Equal => {
7254                self.diff_transforms.next();
7255                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7256                    || self.diff_transforms.item().is_none()
7257                {
7258                    self.excerpts.next();
7259                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7260                    self.diff_transforms.item()
7261                    && self
7262                        .excerpts
7263                        .item()
7264                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7265                {
7266                    self.excerpts.next();
7267                }
7268            }
7269        }
7270    }
7271
7272    fn prev(&mut self) {
7273        self.cached_region.take();
7274        match self
7275            .diff_transforms
7276            .start()
7277            .excerpt_dimension
7278            .cmp(self.excerpts.start())
7279        {
7280            cmp::Ordering::Less => self.excerpts.prev(),
7281            cmp::Ordering::Greater => self.diff_transforms.prev(),
7282            cmp::Ordering::Equal => {
7283                self.diff_transforms.prev();
7284                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7285                    || self.diff_transforms.item().is_none()
7286                {
7287                    self.excerpts.prev();
7288                }
7289            }
7290        }
7291    }
7292
7293    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7294        self.cached_region
7295            .get_or_init(|| self.build_region())
7296            .as_ref()
7297    }
7298
7299    fn is_at_start_of_excerpt(&mut self) -> bool {
7300        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7301            return false;
7302        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7303            return true;
7304        }
7305
7306        self.diff_transforms.prev();
7307        let prev_transform = self.diff_transforms.item();
7308        self.diff_transforms.next();
7309
7310        prev_transform.is_none_or(|next_transform| {
7311            matches!(next_transform, DiffTransform::BufferContent { .. })
7312        })
7313    }
7314
7315    fn is_at_end_of_excerpt(&self) -> bool {
7316        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7317            return false;
7318        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7319            || self.diff_transforms.item().is_none()
7320        {
7321            return true;
7322        }
7323
7324        let next_transform = self.diff_transforms.next_item();
7325        next_transform.is_none_or(|next_transform| match next_transform {
7326            DiffTransform::BufferContent { .. } => true,
7327            DiffTransform::DeletedHunk { hunk_info, .. } => self
7328                .excerpts
7329                .item()
7330                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7331        })
7332    }
7333
7334    fn main_buffer_position(&self) -> Option<BD> {
7335        let excerpt = self.excerpts.item()?;
7336        let buffer = &excerpt.buffer;
7337        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7338        let mut buffer_start = buffer_context_start;
7339        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7340        buffer_start += overshoot;
7341        Some(buffer_start)
7342    }
7343
7344    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7345        let excerpt = self.excerpts.item()?;
7346        match self.diff_transforms.item()? {
7347            DiffTransform::DeletedHunk {
7348                buffer_id,
7349                base_text_byte_range,
7350                has_trailing_newline,
7351                hunk_info,
7352                ..
7353            } => {
7354                let diff = self.diffs.get(buffer_id)?;
7355                let buffer = diff.base_text();
7356                let mut rope_cursor = buffer.as_rope().cursor(0);
7357                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7358                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7359                let mut buffer_end = buffer_start;
7360                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7361                let start = self.diff_transforms.start().output_dimension.0;
7362                let end = self.diff_transforms.end().output_dimension.0;
7363                Some(MultiBufferRegion {
7364                    buffer,
7365                    excerpt,
7366                    has_trailing_newline: *has_trailing_newline,
7367                    is_main_buffer: false,
7368                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7369                        hunk_info.hunk_secondary_status,
7370                    )),
7371                    buffer_range: buffer_start..buffer_end,
7372                    range: start..end,
7373                })
7374            }
7375            DiffTransform::BufferContent {
7376                inserted_hunk_info, ..
7377            } => {
7378                let buffer = &excerpt.buffer;
7379                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7380
7381                let mut start = self.diff_transforms.start().output_dimension.0;
7382                let mut buffer_start = buffer_context_start;
7383                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7384                    let overshoot =
7385                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7386                    start += overshoot;
7387                } else {
7388                    let overshoot =
7389                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7390                    buffer_start += overshoot;
7391                }
7392
7393                let mut end;
7394                let mut buffer_end;
7395                let has_trailing_newline;
7396                let transform_end = self.diff_transforms.end();
7397                if transform_end.excerpt_dimension < self.excerpts.end() {
7398                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7399                    end = transform_end.output_dimension.0;
7400                    buffer_end = buffer_context_start;
7401                    buffer_end += overshoot;
7402                    has_trailing_newline = false;
7403                } else {
7404                    let overshoot =
7405                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7406                    end = self.diff_transforms.start().output_dimension.0;
7407                    end += overshoot;
7408                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7409                    has_trailing_newline = excerpt.has_trailing_newline;
7410                };
7411
7412                let diff_hunk_status = inserted_hunk_info.map(|info| {
7413                    if info.is_logically_deleted {
7414                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7415                    } else {
7416                        DiffHunkStatus::added(info.hunk_secondary_status)
7417                    }
7418                });
7419
7420                Some(MultiBufferRegion {
7421                    buffer,
7422                    excerpt,
7423                    has_trailing_newline,
7424                    is_main_buffer: true,
7425                    diff_hunk_status,
7426                    buffer_range: buffer_start..buffer_end,
7427                    range: start..end,
7428                })
7429            }
7430        }
7431    }
7432
7433    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7434        let excerpt = self.excerpts.item()?;
7435        match self.diff_transforms.item()? {
7436            &DiffTransform::DeletedHunk { .. } => {
7437                let start = self.diff_transforms.start().output_dimension.0;
7438                let end = self.diff_transforms.end().output_dimension.0;
7439                Some((excerpt, start..end))
7440            }
7441            DiffTransform::BufferContent { .. } => {
7442                let mut start = self.diff_transforms.start().output_dimension.0;
7443                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7444                    let overshoot =
7445                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7446                    start += overshoot;
7447                }
7448
7449                let mut end;
7450                let transform_end = self.diff_transforms.end();
7451                if transform_end.excerpt_dimension < self.excerpts.end() {
7452                    end = transform_end.output_dimension.0;
7453                } else {
7454                    let overshoot =
7455                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7456                    end = self.diff_transforms.start().output_dimension.0;
7457                    end += overshoot;
7458                };
7459
7460                Some((excerpt, start..end))
7461            }
7462        }
7463    }
7464
7465    fn excerpt(&self) -> Option<&'a Excerpt> {
7466        self.excerpts.item()
7467    }
7468}
7469
7470impl Excerpt {
7471    fn new(
7472        id: ExcerptId,
7473        locator: Locator,
7474        buffer_id: BufferId,
7475        buffer: Arc<BufferSnapshot>,
7476        range: ExcerptRange<text::Anchor>,
7477        has_trailing_newline: bool,
7478    ) -> Self {
7479        Excerpt {
7480            id,
7481            locator,
7482            max_buffer_row: range.context.end.to_point(&buffer).row,
7483            text_summary: buffer
7484                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7485            buffer_id,
7486            buffer,
7487            range,
7488            has_trailing_newline,
7489        }
7490    }
7491
7492    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7493        let content_start = self.range.context.start.to_offset(&self.buffer);
7494        let chunks_start = content_start + range.start;
7495        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7496
7497        let has_footer = self.has_trailing_newline
7498            && range.start <= self.text_summary.len
7499            && range.end > self.text_summary.len;
7500
7501        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7502
7503        ExcerptChunks {
7504            excerpt_id: self.id,
7505            content_chunks,
7506            has_footer,
7507        }
7508    }
7509
7510    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7511        let content_start = self.range.context.start.to_offset(&self.buffer);
7512        let chunks_start = content_start + range.start;
7513        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7514        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7515        excerpt_chunks.has_footer = self.has_trailing_newline
7516            && range.start <= self.text_summary.len
7517            && range.end > self.text_summary.len;
7518    }
7519
7520    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7521        if text_anchor
7522            .cmp(&self.range.context.start, &self.buffer)
7523            .is_lt()
7524        {
7525            self.range.context.start
7526        } else if text_anchor
7527            .cmp(&self.range.context.end, &self.buffer)
7528            .is_gt()
7529        {
7530            self.range.context.end
7531        } else {
7532            text_anchor
7533        }
7534    }
7535
7536    fn contains(&self, anchor: &Anchor) -> bool {
7537        (anchor.text_anchor.buffer_id == None
7538            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7539            && self
7540                .range
7541                .context
7542                .start
7543                .cmp(&anchor.text_anchor, &self.buffer)
7544                .is_le()
7545            && self
7546                .range
7547                .context
7548                .end
7549                .cmp(&anchor.text_anchor, &self.buffer)
7550                .is_ge()
7551    }
7552
7553    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7554    fn buffer_start_offset(&self) -> BufferOffset {
7555        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7556    }
7557
7558    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7559    fn buffer_end_offset(&self) -> BufferOffset {
7560        self.buffer_start_offset() + self.text_summary.len
7561    }
7562}
7563
7564impl<'a> MultiBufferExcerpt<'a> {
7565    pub fn id(&self) -> ExcerptId {
7566        self.excerpt.id
7567    }
7568
7569    pub fn buffer_id(&self) -> BufferId {
7570        self.excerpt.buffer_id
7571    }
7572
7573    pub fn start_anchor(&self) -> Anchor {
7574        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7575    }
7576
7577    pub fn end_anchor(&self) -> Anchor {
7578        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7579    }
7580
7581    pub fn buffer(&self) -> &'a BufferSnapshot {
7582        &self.excerpt.buffer
7583    }
7584
7585    pub fn buffer_range(&self) -> Range<BufferOffset> {
7586        self.buffer_offset
7587            ..BufferOffset(
7588                self.excerpt
7589                    .range
7590                    .context
7591                    .end
7592                    .to_offset(&self.excerpt.buffer.text),
7593            )
7594    }
7595
7596    pub fn start_offset(&self) -> MultiBufferOffset {
7597        self.offset
7598    }
7599
7600    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7601    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7602        self.map_range_to_buffer(offset..offset).start
7603    }
7604
7605    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7606    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7607        self.diff_transforms
7608            .seek(&OutputDimension(range.start), Bias::Right);
7609        let start = self.map_offset_to_buffer_internal(range.start);
7610        let end = if range.end > range.start {
7611            self.diff_transforms
7612                .seek_forward(&OutputDimension(range.end), Bias::Right);
7613            self.map_offset_to_buffer_internal(range.end)
7614        } else {
7615            start
7616        };
7617        start..end
7618    }
7619
7620    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7621        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7622        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7623            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7624        };
7625        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7626        self.buffer_offset + offset_in_excerpt
7627    }
7628
7629    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7630    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7631        self.map_range_from_buffer(buffer_offset..buffer_offset)
7632            .start
7633    }
7634
7635    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7636    pub fn map_range_from_buffer(
7637        &mut self,
7638        buffer_range: Range<BufferOffset>,
7639    ) -> Range<MultiBufferOffset> {
7640        if buffer_range.start < self.buffer_offset {
7641            log::warn!(
7642                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7643            );
7644            return self.offset..self.offset;
7645        }
7646        let overshoot = buffer_range.start - self.buffer_offset;
7647        let excerpt_offset = self.excerpt_offset + overshoot;
7648        let excerpt_seek_dim = excerpt_offset;
7649        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7650        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7651            log::warn!(
7652                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7653            );
7654            return self.offset..self.offset;
7655        }
7656        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7657        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7658
7659        let end = if buffer_range.start < buffer_range.end {
7660            let overshoot = buffer_range.end - self.buffer_offset;
7661            let excerpt_offset = self.excerpt_offset + overshoot;
7662            let excerpt_seek_dim = excerpt_offset;
7663            self.diff_transforms
7664                .seek_forward(&excerpt_seek_dim, Bias::Right);
7665            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7666            // todo(lw): Clamp end to the excerpt boundaries
7667            self.diff_transforms.start().output_dimension.0 + overshoot
7668        } else {
7669            start
7670        };
7671
7672        start..end
7673    }
7674
7675    /// Returns true if the entirety of the given range is in the buffer's excerpt
7676    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7677        range.start >= self.excerpt.buffer_start_offset()
7678            && range.end <= self.excerpt.buffer_end_offset()
7679    }
7680
7681    /// Returns true if any part of the given range is in the buffer's excerpt
7682    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7683        range.start <= self.excerpt.buffer_end_offset()
7684            && range.end >= self.excerpt.buffer_start_offset()
7685    }
7686
7687    pub fn max_buffer_row(&self) -> u32 {
7688        self.excerpt.max_buffer_row
7689    }
7690}
7691
7692impl ExcerptId {
7693    pub fn min() -> Self {
7694        Self(0)
7695    }
7696
7697    pub fn max() -> Self {
7698        Self(u32::MAX)
7699    }
7700
7701    pub fn to_proto(self) -> u64 {
7702        self.0 as _
7703    }
7704
7705    pub fn from_proto(proto: u64) -> Self {
7706        Self(proto as _)
7707    }
7708
7709    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7710        let a = snapshot.excerpt_locator_for_id(*self);
7711        let b = snapshot.excerpt_locator_for_id(*other);
7712        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7713    }
7714}
7715
7716impl From<ExcerptId> for usize {
7717    fn from(val: ExcerptId) -> Self {
7718        val.0 as usize
7719    }
7720}
7721
7722impl fmt::Debug for Excerpt {
7723    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7724        f.debug_struct("Excerpt")
7725            .field("id", &self.id)
7726            .field("locator", &self.locator)
7727            .field("buffer_id", &self.buffer_id)
7728            .field("range", &self.range)
7729            .field("text_summary", &self.text_summary)
7730            .field("has_trailing_newline", &self.has_trailing_newline)
7731            .finish()
7732    }
7733}
7734
7735impl sum_tree::Item for Excerpt {
7736    type Summary = ExcerptSummary;
7737
7738    fn summary(&self, _cx: ()) -> Self::Summary {
7739        let mut text = self.text_summary;
7740        if self.has_trailing_newline {
7741            text += TextSummary::from("\n");
7742        }
7743        ExcerptSummary {
7744            excerpt_id: self.id,
7745            excerpt_locator: self.locator.clone(),
7746            widest_line_number: self.max_buffer_row,
7747            text: text.into(),
7748            count: 1,
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        self.count += summary.count;
7844    }
7845}
7846
7847impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7848    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7849        Ord::cmp(&Some(self), cursor_location)
7850    }
7851}
7852
7853impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7854    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7855        Ord::cmp(self, &cursor_location.excerpt_locator)
7856    }
7857}
7858
7859impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7860where
7861    MBD: MultiBufferDimension + Default,
7862{
7863    fn zero(_: ()) -> Self {
7864        ExcerptDimension(MBD::default())
7865    }
7866
7867    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7868        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7869    }
7870}
7871
7872impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7873    fn zero(_cx: ()) -> Self {
7874        Default::default()
7875    }
7876
7877    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7878        *self = Some(&summary.excerpt_locator);
7879    }
7880}
7881
7882impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7883    fn zero(_cx: ()) -> Self {
7884        Default::default()
7885    }
7886
7887    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7888        *self = Some(summary.excerpt_id);
7889    }
7890}
7891
7892#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7893struct OutputDimension<T>(T);
7894
7895impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7896    fn eq(&self, other: &T) -> bool {
7897        self.0 == *other
7898    }
7899}
7900
7901impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7902    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7903        self.0.partial_cmp(other)
7904    }
7905}
7906
7907impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7908where
7909    T: ops::Sub<U, Output = R>,
7910{
7911    type Output = R;
7912
7913    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7914        self.0 - other.0
7915    }
7916}
7917
7918impl<R, T, U> ops::Add<U> for OutputDimension<T>
7919where
7920    T: ops::Add<U, Output = R>,
7921{
7922    type Output = OutputDimension<R>;
7923
7924    fn add(self, other: U) -> Self::Output {
7925        OutputDimension(self.0 + other)
7926    }
7927}
7928
7929impl<T, U> AddAssign<U> for OutputDimension<T>
7930where
7931    T: AddAssign<U>,
7932{
7933    fn add_assign(&mut self, other: U) {
7934        self.0 += other;
7935    }
7936}
7937
7938impl<T, U> SubAssign<U> for OutputDimension<T>
7939where
7940    T: SubAssign<U>,
7941{
7942    fn sub_assign(&mut self, other: U) {
7943        self.0 -= other;
7944    }
7945}
7946
7947#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7948struct ExcerptDimension<T>(T);
7949
7950impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7951    fn eq(&self, other: &T) -> bool {
7952        self.0 == *other
7953    }
7954}
7955
7956impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7957    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7958        self.0.partial_cmp(other)
7959    }
7960}
7961
7962impl ExcerptOffset {
7963    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7964        self.0.saturating_sub(other.0)
7965    }
7966}
7967
7968impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7969where
7970    T: ops::Sub<U, Output = R>,
7971{
7972    type Output = R;
7973
7974    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7975        self.0 - other.0
7976    }
7977}
7978
7979impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7980where
7981    T: ops::Add<U, Output = R>,
7982{
7983    type Output = ExcerptDimension<R>;
7984
7985    fn add(self, other: U) -> Self::Output {
7986        ExcerptDimension(self.0 + other)
7987    }
7988}
7989
7990impl<T, U> AddAssign<U> for ExcerptDimension<T>
7991where
7992    T: AddAssign<U>,
7993{
7994    fn add_assign(&mut self, other: U) {
7995        self.0 += other;
7996    }
7997}
7998
7999impl<T, U> SubAssign<U> for ExcerptDimension<T>
8000where
8001    T: SubAssign<U>,
8002{
8003    fn sub_assign(&mut self, other: U) {
8004        self.0 -= other;
8005    }
8006}
8007
8008impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8009    fn zero(_: ()) -> Self {
8010        MultiBufferOffset::ZERO
8011    }
8012
8013    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8014        *self += summary.output.len;
8015    }
8016}
8017
8018impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8019    for ExcerptDimension<MBD>
8020where
8021    MBD: MultiBufferDimension + Ord,
8022{
8023    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8024        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8025    }
8026}
8027
8028impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8029    for ExcerptDimension<MBD>
8030where
8031    MBD: MultiBufferDimension + Ord,
8032{
8033    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8034        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8035    }
8036}
8037
8038impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8039    for ExcerptDimension<MBD>
8040{
8041    fn zero(_: ()) -> Self {
8042        ExcerptDimension(MBD::default())
8043    }
8044
8045    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8046        self.0.add_mb_text_summary(&summary.input)
8047    }
8048}
8049
8050impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8051    for OutputDimension<MBD>
8052where
8053    MBD: MultiBufferDimension + Ord,
8054{
8055    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8056        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8057    }
8058}
8059
8060impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8061    for OutputDimension<MBD>
8062{
8063    fn zero(_: ()) -> Self {
8064        OutputDimension(MBD::default())
8065    }
8066
8067    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8068        self.0.add_mb_text_summary(&summary.output)
8069    }
8070}
8071
8072impl MultiBufferRows<'_> {
8073    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8074        self.point = Point::new(row, 0);
8075        self.cursor.seek(&self.point);
8076    }
8077}
8078
8079impl Iterator for MultiBufferRows<'_> {
8080    type Item = RowInfo;
8081
8082    fn next(&mut self) -> Option<Self::Item> {
8083        if self.is_empty && self.point.row == 0 {
8084            self.point += Point::new(1, 0);
8085            return Some(RowInfo {
8086                buffer_id: None,
8087                buffer_row: Some(0),
8088                multibuffer_row: Some(MultiBufferRow(0)),
8089                diff_status: None,
8090                expand_info: None,
8091                wrapped_buffer_row: None,
8092            });
8093        }
8094
8095        let mut region = self.cursor.region()?.clone();
8096        while self.point >= region.range.end {
8097            self.cursor.next();
8098            if let Some(next_region) = self.cursor.region() {
8099                region = next_region.clone();
8100            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8101                let multibuffer_row = MultiBufferRow(self.point.row);
8102                let last_excerpt = self
8103                    .cursor
8104                    .excerpts
8105                    .item()
8106                    .or(self.cursor.excerpts.prev_item())?;
8107                let last_row = last_excerpt
8108                    .range
8109                    .context
8110                    .end
8111                    .to_point(&last_excerpt.buffer)
8112                    .row;
8113
8114                let first_row = last_excerpt
8115                    .range
8116                    .context
8117                    .start
8118                    .to_point(&last_excerpt.buffer)
8119                    .row;
8120
8121                let expand_info = if self.is_singleton {
8122                    None
8123                } else {
8124                    let needs_expand_up = first_row == last_row
8125                        && last_row > 0
8126                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8127                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8128
8129                    if needs_expand_up && needs_expand_down {
8130                        Some(ExpandExcerptDirection::UpAndDown)
8131                    } else if needs_expand_up {
8132                        Some(ExpandExcerptDirection::Up)
8133                    } else if needs_expand_down {
8134                        Some(ExpandExcerptDirection::Down)
8135                    } else {
8136                        None
8137                    }
8138                    .map(|direction| ExpandInfo {
8139                        direction,
8140                        excerpt_id: last_excerpt.id,
8141                    })
8142                };
8143                self.point += Point::new(1, 0);
8144                return Some(RowInfo {
8145                    buffer_id: Some(last_excerpt.buffer_id),
8146                    buffer_row: Some(last_row),
8147                    multibuffer_row: Some(multibuffer_row),
8148                    diff_status: None,
8149                    wrapped_buffer_row: None,
8150                    expand_info,
8151                });
8152            } else {
8153                return None;
8154            };
8155        }
8156
8157        let overshoot = self.point - region.range.start;
8158        let buffer_point = region.buffer_range.start + overshoot;
8159        let expand_info = if self.is_singleton {
8160            None
8161        } else {
8162            let needs_expand_up = self.point.row == region.range.start.row
8163                && self.cursor.is_at_start_of_excerpt()
8164                && buffer_point.row > 0;
8165            let needs_expand_down = (region.excerpt.has_trailing_newline
8166                && self.point.row + 1 == region.range.end.row
8167                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8168                && self.cursor.is_at_end_of_excerpt()
8169                && buffer_point.row < region.buffer.max_point().row;
8170
8171            if needs_expand_up && needs_expand_down {
8172                Some(ExpandExcerptDirection::UpAndDown)
8173            } else if needs_expand_up {
8174                Some(ExpandExcerptDirection::Up)
8175            } else if needs_expand_down {
8176                Some(ExpandExcerptDirection::Down)
8177            } else {
8178                None
8179            }
8180            .map(|direction| ExpandInfo {
8181                direction,
8182                excerpt_id: region.excerpt.id,
8183            })
8184        };
8185
8186        let result = Some(RowInfo {
8187            buffer_id: Some(region.buffer.remote_id()),
8188            buffer_row: Some(buffer_point.row),
8189            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8190            diff_status: region
8191                .diff_hunk_status
8192                .filter(|_| self.point < region.range.end),
8193            expand_info,
8194            wrapped_buffer_row: None,
8195        });
8196        self.point += Point::new(1, 0);
8197        result
8198    }
8199}
8200
8201impl<'a> MultiBufferChunks<'a> {
8202    pub fn offset(&self) -> MultiBufferOffset {
8203        self.range.start
8204    }
8205
8206    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8207        self.diff_transforms.seek(&range.end, Bias::Right);
8208        let mut excerpt_end = self.diff_transforms.start().1;
8209        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8210            let overshoot = range.end - self.diff_transforms.start().0;
8211            excerpt_end += overshoot;
8212        }
8213
8214        self.diff_transforms.seek(&range.start, Bias::Right);
8215        let mut excerpt_start = self.diff_transforms.start().1;
8216        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8217            let overshoot = range.start - self.diff_transforms.start().0;
8218            excerpt_start += overshoot;
8219        }
8220
8221        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8222        self.buffer_chunk.take();
8223        self.range = range;
8224    }
8225
8226    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8227        self.excerpt_offset_range = new_range.clone();
8228        self.excerpts.seek(&new_range.start, Bias::Right);
8229        if let Some(excerpt) = self.excerpts.item() {
8230            let excerpt_start = *self.excerpts.start();
8231            if let Some(excerpt_chunks) = self
8232                .excerpt_chunks
8233                .as_mut()
8234                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8235            {
8236                excerpt.seek_chunks(
8237                    excerpt_chunks,
8238                    (self.excerpt_offset_range.start - excerpt_start)
8239                        ..(self.excerpt_offset_range.end - excerpt_start),
8240                );
8241            } else {
8242                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8243                    (self.excerpt_offset_range.start - excerpt_start)
8244                        ..(self.excerpt_offset_range.end - excerpt_start),
8245                    self.language_aware,
8246                ));
8247            }
8248        } else {
8249            self.excerpt_chunks = None;
8250        }
8251    }
8252
8253    #[ztracing::instrument(skip_all)]
8254    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8255        loop {
8256            if self.excerpt_offset_range.is_empty() {
8257                return None;
8258            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8259                self.excerpt_offset_range.start += chunk.text.len();
8260                return Some(chunk);
8261            } else {
8262                self.excerpts.next();
8263                let excerpt = self.excerpts.item()?;
8264                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8265                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8266                    self.language_aware,
8267                ));
8268            }
8269        }
8270    }
8271}
8272
8273impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8274    type Item = &'a str;
8275
8276    fn next(&mut self) -> Option<Self::Item> {
8277        let mut region = self.cursor.region()?;
8278        if self.offset == region.range.start {
8279            self.cursor.prev();
8280            region = self.cursor.region()?;
8281            let start_overshoot = self.start.saturating_sub(region.range.start);
8282            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8283                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8284            ));
8285        }
8286
8287        if self.offset == region.range.end && region.has_trailing_newline {
8288            self.offset -= 1;
8289            Some("\n")
8290        } else {
8291            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8292            self.offset -= chunk.len();
8293            Some(chunk)
8294        }
8295    }
8296}
8297
8298impl<'a> Iterator for MultiBufferChunks<'a> {
8299    type Item = Chunk<'a>;
8300
8301    #[ztracing::instrument(skip_all)]
8302    fn next(&mut self) -> Option<Chunk<'a>> {
8303        if self.range.start >= self.range.end {
8304            return None;
8305        }
8306        if self.range.start == self.diff_transforms.end().0 {
8307            self.diff_transforms.next();
8308        }
8309
8310        let diff_transform_start = self.diff_transforms.start().0;
8311        let diff_transform_end = self.diff_transforms.end().0;
8312        debug_assert!(
8313            self.range.start < diff_transform_end,
8314            "{:?} < {:?} of ({1:?}..{2:?})",
8315            self.range.start,
8316            diff_transform_end,
8317            diff_transform_start
8318        );
8319
8320        let diff_transform = self.diff_transforms.item()?;
8321        match diff_transform {
8322            DiffTransform::BufferContent { .. } => {
8323                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8324                    chunk
8325                } else {
8326                    let chunk = self.next_excerpt_chunk().unwrap();
8327                    self.buffer_chunk.insert(chunk)
8328                };
8329
8330                let chunk_end = self.range.start + chunk.text.len();
8331                let diff_transform_end = diff_transform_end.min(self.range.end);
8332
8333                if diff_transform_end < chunk_end {
8334                    let split_idx = diff_transform_end - self.range.start;
8335                    let (before, after) = chunk.text.split_at(split_idx);
8336                    self.range.start = diff_transform_end;
8337                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8338                    let chars = chunk.chars & mask;
8339                    let tabs = chunk.tabs & mask;
8340
8341                    chunk.text = after;
8342                    chunk.chars = chunk.chars >> split_idx;
8343                    chunk.tabs = chunk.tabs >> split_idx;
8344
8345                    Some(Chunk {
8346                        text: before,
8347                        chars,
8348                        tabs,
8349                        ..chunk.clone()
8350                    })
8351                } else {
8352                    self.range.start = chunk_end;
8353                    self.buffer_chunk.take()
8354                }
8355            }
8356            DiffTransform::DeletedHunk {
8357                buffer_id,
8358                base_text_byte_range,
8359                has_trailing_newline,
8360                ..
8361            } => {
8362                let base_text_start =
8363                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8364                let base_text_end =
8365                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8366                let base_text_end = base_text_end.min(base_text_byte_range.end);
8367
8368                let mut chunks = if let Some((_, mut chunks)) = self
8369                    .diff_base_chunks
8370                    .take()
8371                    .filter(|(id, _)| id == buffer_id)
8372                {
8373                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8374                    {
8375                        chunks.seek(base_text_start..base_text_end);
8376                    }
8377                    chunks
8378                } else {
8379                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8380                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8381                };
8382
8383                let chunk = if let Some(chunk) = chunks.next() {
8384                    self.range.start += chunk.text.len();
8385                    self.diff_base_chunks = Some((*buffer_id, chunks));
8386                    chunk
8387                } else {
8388                    debug_assert!(has_trailing_newline);
8389                    self.range.start += "\n".len();
8390                    Chunk {
8391                        text: "\n",
8392                        chars: 1u128,
8393                        ..Default::default()
8394                    }
8395                };
8396                Some(chunk)
8397            }
8398        }
8399    }
8400}
8401
8402impl MultiBufferBytes<'_> {
8403    fn consume(&mut self, len: usize) {
8404        self.range.start += len;
8405        self.chunk = &self.chunk[len..];
8406
8407        if !self.range.is_empty() && self.chunk.is_empty() {
8408            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8409                self.chunk = chunk;
8410            } else if self.has_trailing_newline {
8411                self.has_trailing_newline = false;
8412                self.chunk = b"\n";
8413            } else {
8414                self.cursor.next();
8415                if let Some(region) = self.cursor.region() {
8416                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8417                        region.buffer_range.start
8418                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8419                                .min(region.buffer_range.end),
8420                    );
8421                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8422                    self.excerpt_bytes = Some(excerpt_bytes);
8423                    self.has_trailing_newline =
8424                        region.has_trailing_newline && self.range.end >= region.range.end;
8425                    if self.chunk.is_empty() && self.has_trailing_newline {
8426                        self.has_trailing_newline = false;
8427                        self.chunk = b"\n";
8428                    }
8429                }
8430            }
8431        }
8432    }
8433}
8434
8435impl<'a> Iterator for MultiBufferBytes<'a> {
8436    type Item = &'a [u8];
8437
8438    fn next(&mut self) -> Option<Self::Item> {
8439        let chunk = self.chunk;
8440        if chunk.is_empty() {
8441            None
8442        } else {
8443            self.consume(chunk.len());
8444            Some(chunk)
8445        }
8446    }
8447}
8448
8449impl io::Read for MultiBufferBytes<'_> {
8450    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8451        let len = cmp::min(buf.len(), self.chunk.len());
8452        buf[..len].copy_from_slice(&self.chunk[..len]);
8453        if len > 0 {
8454            self.consume(len);
8455        }
8456        Ok(len)
8457    }
8458}
8459
8460impl io::Read for ReversedMultiBufferBytes<'_> {
8461    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8462        let len = cmp::min(buf.len(), self.chunk.len());
8463        buf[..len].copy_from_slice(&self.chunk[..len]);
8464        buf[..len].reverse();
8465        if len > 0 {
8466            self.range.end -= len;
8467            self.chunk = &self.chunk[..self.chunk.len() - len];
8468            if !self.range.is_empty()
8469                && self.chunk.is_empty()
8470                && let Some(chunk) = self.chunks.next()
8471            {
8472                self.chunk = chunk.as_bytes();
8473            }
8474        }
8475        Ok(len)
8476    }
8477}
8478
8479impl<'a> Iterator for ExcerptChunks<'a> {
8480    type Item = Chunk<'a>;
8481
8482    fn next(&mut self) -> Option<Self::Item> {
8483        if let Some(chunk) = self.content_chunks.next() {
8484            return Some(chunk);
8485        }
8486
8487        if self.has_footer {
8488            let text = "\n";
8489            let chars = 0b1;
8490            self.has_footer = false;
8491            return Some(Chunk {
8492                text,
8493                chars,
8494                ..Default::default()
8495            });
8496        }
8497
8498        None
8499    }
8500}
8501
8502impl ToOffset for Point {
8503    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8504        snapshot.point_to_offset(*self)
8505    }
8506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8507        snapshot.point_to_offset_utf16(*self)
8508    }
8509}
8510
8511impl ToOffset for MultiBufferOffset {
8512    #[track_caller]
8513    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8514        assert!(
8515            *self <= snapshot.len(),
8516            "offset {} is greater than the snapshot.len() {}",
8517            self.0,
8518            snapshot.len().0,
8519        );
8520        *self
8521    }
8522    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8523        snapshot.offset_to_offset_utf16(*self)
8524    }
8525}
8526
8527impl ToOffset for MultiBufferOffsetUtf16 {
8528    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8529        snapshot.offset_utf16_to_offset(*self)
8530    }
8531
8532    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8533        *self
8534    }
8535}
8536
8537impl ToOffset for PointUtf16 {
8538    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8539        snapshot.point_utf16_to_offset(*self)
8540    }
8541    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8542        snapshot.point_utf16_to_offset_utf16(*self)
8543    }
8544}
8545
8546impl ToPoint for MultiBufferOffset {
8547    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8548        snapshot.offset_to_point(*self)
8549    }
8550    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8551        snapshot.offset_to_point_utf16(*self)
8552    }
8553}
8554
8555impl ToPoint for Point {
8556    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8557        *self
8558    }
8559    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8560        snapshot.point_to_point_utf16(*self)
8561    }
8562}
8563
8564impl ToPoint for PointUtf16 {
8565    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8566        snapshot.point_utf16_to_point(*self)
8567    }
8568    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8569        *self
8570    }
8571}
8572
8573impl From<ExcerptId> for EntityId {
8574    fn from(id: ExcerptId) -> Self {
8575        EntityId::from(id.0 as u64)
8576    }
8577}
8578
8579#[cfg(debug_assertions)]
8580pub mod debug {
8581    use super::*;
8582
8583    pub trait ToMultiBufferDebugRanges {
8584        fn to_multi_buffer_debug_ranges(
8585            &self,
8586            snapshot: &MultiBufferSnapshot,
8587        ) -> Vec<Range<MultiBufferOffset>>;
8588    }
8589
8590    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8591        fn to_multi_buffer_debug_ranges(
8592            &self,
8593            snapshot: &MultiBufferSnapshot,
8594        ) -> Vec<Range<MultiBufferOffset>> {
8595            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8596        }
8597    }
8598
8599    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8600        fn to_multi_buffer_debug_ranges(
8601            &self,
8602            snapshot: &MultiBufferSnapshot,
8603        ) -> Vec<Range<MultiBufferOffset>> {
8604            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8605                .to_multi_buffer_debug_ranges(snapshot)
8606        }
8607    }
8608
8609    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8610        fn to_multi_buffer_debug_ranges(
8611            &self,
8612            snapshot: &MultiBufferSnapshot,
8613        ) -> Vec<Range<MultiBufferOffset>> {
8614            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8615        }
8616    }
8617
8618    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8619        fn to_multi_buffer_debug_ranges(
8620            &self,
8621            snapshot: &MultiBufferSnapshot,
8622        ) -> Vec<Range<MultiBufferOffset>> {
8623            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8624        }
8625    }
8626
8627    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8628        fn to_multi_buffer_debug_ranges(
8629            &self,
8630            snapshot: &MultiBufferSnapshot,
8631        ) -> Vec<Range<MultiBufferOffset>> {
8632            self.iter()
8633                .map(|item| {
8634                    let offset = item.to_offset(snapshot);
8635                    offset..offset
8636                })
8637                .collect()
8638        }
8639    }
8640
8641    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8642        fn to_multi_buffer_debug_ranges(
8643            &self,
8644            snapshot: &MultiBufferSnapshot,
8645        ) -> Vec<Range<MultiBufferOffset>> {
8646            self.iter()
8647                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8648                .collect()
8649        }
8650    }
8651}