multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunkSecondaryStatus,
  14    DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58use ztracing::instrument;
  59
  60pub use self::path_key::{PathExcerptInsertResult, PathKey};
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 519    excerpts: Vec<Locator>,
 520    _subscriptions: [gpui::Subscription; 2],
 521}
 522
 523struct DiffState {
 524    diff: Entity<BufferDiff>,
 525    is_inverted: bool,
 526    _subscription: gpui::Subscription,
 527}
 528
 529impl DiffState {
 530    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 531        DiffStateSnapshot {
 532            diff: self.diff.read(cx).snapshot(cx),
 533            is_inverted: self.is_inverted,
 534        }
 535    }
 536}
 537
 538#[derive(Clone)]
 539struct DiffStateSnapshot {
 540    diff: BufferDiffSnapshot,
 541    is_inverted: bool,
 542}
 543
 544impl std::ops::Deref for DiffStateSnapshot {
 545    type Target = BufferDiffSnapshot;
 546
 547    fn deref(&self) -> &Self::Target {
 548        &self.diff
 549    }
 550}
 551
 552impl DiffState {
 553    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 554        DiffState {
 555            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 556                BufferDiffEvent::DiffChanged(DiffChanged {
 557                    changed_range,
 558                    base_text_changed_range: _,
 559                    extended_range,
 560                }) => {
 561                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 562                    let range = if use_extended {
 563                        extended_range.clone()
 564                    } else {
 565                        changed_range.clone()
 566                    };
 567                    if let Some(range) = range {
 568                        this.buffer_diff_changed(diff, range, cx)
 569                    }
 570                    cx.emit(Event::BufferDiffChanged);
 571                }
 572                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 573                _ => {}
 574            }),
 575            diff,
 576            is_inverted: false,
 577        }
 578    }
 579
 580    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 581        DiffState {
 582            _subscription: cx.subscribe(&diff, {
 583                move |this, diff, event, cx| match event {
 584                    BufferDiffEvent::DiffChanged(DiffChanged {
 585                        changed_range: _,
 586                        base_text_changed_range,
 587                        extended_range: _,
 588                    }) => {
 589                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 590                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 591                        }
 592                        cx.emit(Event::BufferDiffChanged);
 593                    }
 594                    BufferDiffEvent::LanguageChanged => {
 595                        this.inverted_buffer_diff_language_changed(diff, cx)
 596                    }
 597                    _ => {}
 598                }
 599            }),
 600            diff,
 601            is_inverted: true,
 602        }
 603    }
 604}
 605
 606/// The contents of a [`MultiBuffer`] at a single point in time.
 607#[derive(Clone, Default)]
 608pub struct MultiBufferSnapshot {
 609    excerpts: SumTree<Excerpt>,
 610    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 611    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 612    diff_transforms: SumTree<DiffTransform>,
 613    excerpt_ids: SumTree<ExcerptIdMapping>,
 614    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 615    non_text_state_update_count: usize,
 616    edit_count: usize,
 617    is_dirty: bool,
 618    has_deleted_file: bool,
 619    has_conflict: bool,
 620    has_inverted_diff: bool,
 621    singleton: bool,
 622    trailing_excerpt_update_count: usize,
 623    all_diff_hunks_expanded: bool,
 624    show_deleted_hunks: bool,
 625    use_extended_diff_range: bool,
 626    show_headers: bool,
 627}
 628
 629// follower: None
 630// - BufferContent(Some)
 631// - BufferContent(None)
 632// - DeletedHunk
 633//
 634// follower: Some
 635// - BufferContent(Some)
 636// - BufferContent(None)
 637
 638#[derive(Debug, Clone)]
 639enum DiffTransform {
 640    // RealText
 641    BufferContent {
 642        summary: MBTextSummary,
 643        // modified_hunk_info
 644        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 645    },
 646    // ExpandedHunkText
 647    DeletedHunk {
 648        summary: TextSummary,
 649        buffer_id: BufferId,
 650        hunk_info: DiffTransformHunkInfo,
 651        base_text_byte_range: Range<usize>,
 652        has_trailing_newline: bool,
 653    },
 654}
 655
 656#[derive(Clone, Copy, Debug)]
 657struct DiffTransformHunkInfo {
 658    excerpt_id: ExcerptId,
 659    hunk_start_anchor: text::Anchor,
 660    hunk_secondary_status: DiffHunkSecondaryStatus,
 661    is_logically_deleted: bool,
 662}
 663
 664impl Eq for DiffTransformHunkInfo {}
 665
 666impl PartialEq for DiffTransformHunkInfo {
 667    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 668        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 669    }
 670}
 671
 672impl std::hash::Hash for DiffTransformHunkInfo {
 673    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 674        self.excerpt_id.hash(state);
 675        self.hunk_start_anchor.hash(state);
 676    }
 677}
 678
 679#[derive(Clone)]
 680pub struct ExcerptInfo {
 681    pub id: ExcerptId,
 682    pub buffer: Arc<BufferSnapshot>,
 683    pub buffer_id: BufferId,
 684    pub range: ExcerptRange<text::Anchor>,
 685    pub end_row: MultiBufferRow,
 686}
 687
 688impl std::fmt::Debug for ExcerptInfo {
 689    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 690        f.debug_struct(type_name::<Self>())
 691            .field("id", &self.id)
 692            .field("buffer_id", &self.buffer_id)
 693            .field("path", &self.buffer.file().map(|f| f.path()))
 694            .field("range", &self.range)
 695            .finish()
 696    }
 697}
 698
 699/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 700#[derive(Debug)]
 701pub struct ExcerptBoundary {
 702    pub prev: Option<ExcerptInfo>,
 703    pub next: ExcerptInfo,
 704    /// The row in the `MultiBuffer` where the boundary is located
 705    pub row: MultiBufferRow,
 706}
 707
 708impl ExcerptBoundary {
 709    pub fn starts_new_buffer(&self) -> bool {
 710        match (self.prev.as_ref(), &self.next) {
 711            (None, _) => true,
 712            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 713        }
 714    }
 715}
 716
 717#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 718pub struct ExpandInfo {
 719    pub direction: ExpandExcerptDirection,
 720    pub excerpt_id: ExcerptId,
 721}
 722
 723#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 724pub struct RowInfo {
 725    pub buffer_id: Option<BufferId>,
 726    pub buffer_row: Option<u32>,
 727    pub multibuffer_row: Option<MultiBufferRow>,
 728    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 729    pub expand_info: Option<ExpandInfo>,
 730    pub wrapped_buffer_row: Option<u32>,
 731}
 732
 733/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 734#[derive(Clone)]
 735struct Excerpt {
 736    /// The unique identifier for this excerpt
 737    id: ExcerptId,
 738    /// The location of the excerpt in the [`MultiBuffer`]
 739    locator: Locator,
 740    /// The buffer being excerpted
 741    buffer_id: BufferId,
 742    /// A snapshot of the buffer being excerpted
 743    buffer: Arc<BufferSnapshot>,
 744    /// The range of the buffer to be shown in the excerpt
 745    range: ExcerptRange<text::Anchor>,
 746    /// The last row in the excerpted slice of the buffer
 747    max_buffer_row: BufferRow,
 748    /// A summary of the text in the excerpt
 749    text_summary: TextSummary,
 750    has_trailing_newline: bool,
 751}
 752
 753/// A public view into an `Excerpt` in a [`MultiBuffer`].
 754///
 755/// Contains methods for getting the [`Buffer`] of the excerpt,
 756/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 757#[derive(Clone)]
 758pub struct MultiBufferExcerpt<'a> {
 759    excerpt: &'a Excerpt,
 760    diff_transforms:
 761        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 762    /// The offset in the multibuffer considering diff transforms.
 763    offset: MultiBufferOffset,
 764    /// The offset in the multibuffer without diff transforms.
 765    excerpt_offset: ExcerptOffset,
 766    buffer_offset: BufferOffset,
 767}
 768
 769#[derive(Clone, Debug)]
 770struct ExcerptIdMapping {
 771    id: ExcerptId,
 772    locator: Locator,
 773}
 774
 775/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 776/// These ranges are relative to the buffer itself
 777#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 778pub struct ExcerptRange<T> {
 779    /// The full range of text to be shown in the excerpt.
 780    pub context: Range<T>,
 781    /// The primary range of text to be highlighted in the excerpt.
 782    /// In a multi-buffer search, this would be the text that matched the search
 783    pub primary: Range<T>,
 784}
 785
 786impl<T: Clone> ExcerptRange<T> {
 787    pub fn new(context: Range<T>) -> Self {
 788        Self {
 789            context: context.clone(),
 790            primary: context,
 791        }
 792    }
 793}
 794
 795#[derive(Clone, Debug, Default)]
 796pub struct ExcerptSummary {
 797    excerpt_id: ExcerptId,
 798    /// The location of the last [`Excerpt`] being summarized
 799    excerpt_locator: Locator,
 800    widest_line_number: u32,
 801    text: MBTextSummary,
 802    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_buffer().read(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_buffer().read(cx).remote_id();
2478        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2479            return;
2480        };
2481
2482        let new_diff = DiffStateSnapshot {
2483            diff: diff.snapshot(cx),
2484            is_inverted: true,
2485        };
2486        let mut snapshot = self.snapshot.get_mut();
2487        snapshot
2488            .diffs
2489            .insert_or_replace(base_text_buffer_id, new_diff);
2490
2491        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2492        let edits = Self::sync_diff_transforms(
2493            &mut snapshot,
2494            excerpt_edits,
2495            DiffChangeKind::DiffUpdated {
2496                // We don't read this field for inverted diffs.
2497                base_changed: false,
2498            },
2499        );
2500        if !edits.is_empty() {
2501            self.subscriptions.publish(edits);
2502        }
2503        cx.emit(Event::Edited {
2504            edited_buffer: None,
2505        });
2506    }
2507
2508    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2509        self.buffers.values().map(|state| state.buffer.clone())
2510    }
2511
2512    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2513        self.all_buffers_iter().collect()
2514    }
2515
2516    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2517        self.buffers.keys().copied()
2518    }
2519
2520    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2521        self.all_buffer_ids_iter().collect()
2522    }
2523
2524    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2525        self.buffers
2526            .get(&buffer_id)
2527            .map(|state| state.buffer.clone())
2528    }
2529
2530    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2531        self.point_to_buffer_offset(point, cx)
2532            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2533    }
2534
2535    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2536        let buffer_id = self
2537            .snapshot
2538            .borrow()
2539            .excerpts
2540            .first()
2541            .map(|excerpt| excerpt.buffer.remote_id());
2542        buffer_id
2543            .and_then(|buffer_id| self.buffer(buffer_id))
2544            .map(|buffer| {
2545                let buffer = buffer.read(cx);
2546                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2547            })
2548            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2549    }
2550
2551    pub fn language_settings_at<'a, T: ToOffset>(
2552        &'a self,
2553        point: T,
2554        cx: &'a App,
2555    ) -> Cow<'a, LanguageSettings> {
2556        let mut language = None;
2557        let mut file = None;
2558        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2559            let buffer = buffer.read(cx);
2560            language = buffer.language_at(offset);
2561            file = buffer.file();
2562        }
2563        language_settings(language.map(|l| l.name()), file, cx)
2564    }
2565
2566    pub fn for_each_buffer(&self, f: &mut dyn FnMut(&Entity<Buffer>)) {
2567        self.buffers.values().for_each(|state| f(&state.buffer))
2568    }
2569
2570    pub fn explicit_title(&self) -> Option<&str> {
2571        self.title.as_deref()
2572    }
2573
2574    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2575        if let Some(title) = self.title.as_ref() {
2576            return title.into();
2577        }
2578
2579        if let Some(buffer) = self.as_singleton() {
2580            let buffer = buffer.read(cx);
2581
2582            if let Some(file) = buffer.file() {
2583                return file.file_name(cx).into();
2584            }
2585
2586            if let Some(title) = self.buffer_content_title(buffer) {
2587                return title;
2588            }
2589        };
2590
2591        "untitled".into()
2592    }
2593
2594    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2595        let mut is_leading_whitespace = true;
2596        let mut count = 0;
2597        let mut prev_was_space = false;
2598        let mut title = String::new();
2599
2600        for ch in buffer.snapshot().chars() {
2601            if is_leading_whitespace && ch.is_whitespace() {
2602                continue;
2603            }
2604
2605            is_leading_whitespace = false;
2606
2607            if ch == '\n' || count >= 40 {
2608                break;
2609            }
2610
2611            if ch.is_whitespace() {
2612                if !prev_was_space {
2613                    title.push(' ');
2614                    count += 1;
2615                    prev_was_space = true;
2616                }
2617            } else {
2618                title.push(ch);
2619                count += 1;
2620                prev_was_space = false;
2621            }
2622        }
2623
2624        let title = title.trim_end().to_string();
2625
2626        if title.is_empty() {
2627            return None;
2628        }
2629
2630        Some(title.into())
2631    }
2632
2633    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2634        self.title = Some(title);
2635        cx.notify();
2636    }
2637
2638    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2639    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2640        for buffer_state in self.buffers.values() {
2641            buffer_state
2642                .buffer
2643                .update(cx, |buffer, _cx| buffer.refresh_preview());
2644        }
2645    }
2646
2647    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2648    pub fn preserve_preview(&self, cx: &App) -> bool {
2649        self.buffers
2650            .values()
2651            .all(|state| state.buffer.read(cx).preserve_preview())
2652    }
2653
2654    #[cfg(any(test, feature = "test-support"))]
2655    pub fn is_parsing(&self, cx: &App) -> bool {
2656        self.as_singleton().unwrap().read(cx).is_parsing()
2657    }
2658
2659    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2660        let buffer_id = diff.read(cx).buffer_id;
2661
2662        if let Some(existing_diff) = self.diff_for(buffer_id)
2663            && diff.entity_id() == existing_diff.entity_id()
2664        {
2665            return;
2666        }
2667
2668        self.buffer_diff_changed(
2669            diff.clone(),
2670            text::Anchor::min_max_range_for_buffer(buffer_id),
2671            cx,
2672        );
2673        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2674    }
2675
2676    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2677        let snapshot = diff.read(cx).base_text(cx);
2678        let base_text_buffer_id = snapshot.remote_id();
2679        let diff_change_range = 0..snapshot.len();
2680        self.snapshot.get_mut().has_inverted_diff = true;
2681        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2682        self.diffs
2683            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2684    }
2685
2686    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2687        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2688    }
2689
2690    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2691        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2692    }
2693
2694    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2695        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2696    }
2697
2698    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2699        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2700        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2701    }
2702
2703    pub fn all_diff_hunks_expanded(&self) -> bool {
2704        self.snapshot.borrow().all_diff_hunks_expanded
2705    }
2706
2707    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2708        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2709        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2710    }
2711
2712    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2713        self.snapshot.get_mut().show_deleted_hunks = show;
2714
2715        self.sync_mut(cx);
2716
2717        let old_len = self.snapshot.borrow().len();
2718
2719        let ranges = std::iter::once((Point::zero()..Point::MAX, ExcerptId::max()));
2720        let _ = self.expand_or_collapse_diff_hunks_inner(ranges, true, cx);
2721
2722        let new_len = self.snapshot.borrow().len();
2723
2724        self.subscriptions.publish(vec![Edit {
2725            old: MultiBufferOffset(0)..old_len,
2726            new: MultiBufferOffset(0)..new_len,
2727        }]);
2728
2729        cx.emit(Event::DiffHunksToggled);
2730        cx.emit(Event::Edited {
2731            edited_buffer: None,
2732        });
2733    }
2734
2735    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2736        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2737    }
2738
2739    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2740        self.read(cx)
2741            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2742            .nth(1)
2743            .is_some()
2744    }
2745
2746    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2747        let snapshot = self.read(cx);
2748        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2749        let offset_range = range.to_offset(&snapshot);
2750        cursor.seek(&offset_range.start, Bias::Left);
2751        while let Some(item) = cursor.item() {
2752            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2753                break;
2754            }
2755            if item.hunk_info().is_some() {
2756                return true;
2757            }
2758            cursor.next();
2759        }
2760        false
2761    }
2762
2763    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2764        let snapshot = self.read(cx);
2765        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2766        for range in ranges {
2767            let range = range.to_point(&snapshot);
2768            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2769            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2770                .min(snapshot.len());
2771            cursor.seek(&start, Bias::Right);
2772            while let Some(item) = cursor.item() {
2773                if *cursor.start() >= end {
2774                    break;
2775                }
2776                if item.hunk_info().is_some() {
2777                    return true;
2778                }
2779                cursor.next();
2780            }
2781        }
2782        false
2783    }
2784
2785    pub fn expand_or_collapse_diff_hunks_inner(
2786        &mut self,
2787        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2788        expand: bool,
2789        cx: &mut Context<Self>,
2790    ) -> Vec<Edit<MultiBufferOffset>> {
2791        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2792            return Vec::new();
2793        }
2794        self.sync_mut(cx);
2795        let mut snapshot = self.snapshot.get_mut();
2796        let mut excerpt_edits = Vec::new();
2797        let mut last_hunk_row = None;
2798        for (range, end_excerpt_id) in ranges {
2799            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2800                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2801                    continue;
2802                }
2803                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2804                    continue;
2805                }
2806                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2807                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2808                let start = snapshot.excerpt_offset_for_anchor(&start);
2809                let end = snapshot.excerpt_offset_for_anchor(&end);
2810                last_hunk_row = Some(diff_hunk.row_range.start);
2811                excerpt_edits.push(text::Edit {
2812                    old: start..end,
2813                    new: start..end,
2814                });
2815            }
2816        }
2817
2818        Self::sync_diff_transforms(
2819            &mut snapshot,
2820            excerpt_edits,
2821            DiffChangeKind::ExpandOrCollapseHunks { expand },
2822        )
2823    }
2824
2825    pub fn expand_or_collapse_diff_hunks(
2826        &mut self,
2827        ranges: Vec<Range<Anchor>>,
2828        expand: bool,
2829        cx: &mut Context<Self>,
2830    ) {
2831        let snapshot = self.snapshot.borrow().clone();
2832        let ranges = ranges.iter().map(move |range| {
2833            let end_excerpt_id = range.end.excerpt_id;
2834            let range = range.to_point(&snapshot);
2835            let mut peek_end = range.end;
2836            if range.end.row < snapshot.max_row().0 {
2837                peek_end = Point::new(range.end.row + 1, 0);
2838            };
2839            (range.start..peek_end, end_excerpt_id)
2840        });
2841        let edits = self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2842        if !edits.is_empty() {
2843            self.subscriptions.publish(edits);
2844        }
2845        cx.emit(Event::DiffHunksToggled);
2846        cx.emit(Event::Edited {
2847            edited_buffer: None,
2848        });
2849    }
2850
2851    pub fn resize_excerpt(
2852        &mut self,
2853        id: ExcerptId,
2854        range: Range<text::Anchor>,
2855        cx: &mut Context<Self>,
2856    ) {
2857        self.sync_mut(cx);
2858
2859        let mut snapshot = self.snapshot.get_mut();
2860        let locator = snapshot.excerpt_locator_for_id(id);
2861        let mut new_excerpts = SumTree::default();
2862        let mut cursor = snapshot
2863            .excerpts
2864            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2865        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2866
2867        let prefix = cursor.slice(&Some(locator), Bias::Left);
2868        new_excerpts.append(prefix, ());
2869
2870        let mut excerpt = cursor.item().unwrap().clone();
2871        let old_text_len = excerpt.text_summary.len;
2872
2873        excerpt.range.context.start = range.start;
2874        excerpt.range.context.end = range.end;
2875        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2876
2877        excerpt.text_summary = excerpt
2878            .buffer
2879            .text_summary_for_range(excerpt.range.context.clone());
2880
2881        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2882        let old_start_offset = cursor.start().1;
2883        let new_text_len = excerpt.text_summary.len;
2884        let edit = Edit {
2885            old: old_start_offset..old_start_offset + old_text_len,
2886            new: new_start_offset..new_start_offset + new_text_len,
2887        };
2888
2889        if let Some(last_edit) = edits.last_mut() {
2890            if last_edit.old.end == edit.old.start {
2891                last_edit.old.end = edit.old.end;
2892                last_edit.new.end = edit.new.end;
2893            } else {
2894                edits.push(edit);
2895            }
2896        } else {
2897            edits.push(edit);
2898        }
2899
2900        new_excerpts.push(excerpt, ());
2901
2902        cursor.next();
2903
2904        new_excerpts.append(cursor.suffix(), ());
2905
2906        drop(cursor);
2907        snapshot.excerpts = new_excerpts;
2908
2909        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2910        if !edits.is_empty() {
2911            self.subscriptions.publish(edits);
2912        }
2913        cx.emit(Event::Edited {
2914            edited_buffer: None,
2915        });
2916        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2917        cx.notify();
2918    }
2919
2920    pub fn expand_excerpts(
2921        &mut self,
2922        ids: impl IntoIterator<Item = ExcerptId>,
2923        line_count: u32,
2924        direction: ExpandExcerptDirection,
2925        cx: &mut Context<Self>,
2926    ) {
2927        if line_count == 0 {
2928            return;
2929        }
2930        self.sync_mut(cx);
2931        if !self.excerpts_by_path.is_empty() {
2932            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2933            return;
2934        }
2935        let mut snapshot = self.snapshot.get_mut();
2936
2937        let ids = ids.into_iter().collect::<Vec<_>>();
2938        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2939        let mut new_excerpts = SumTree::default();
2940        let mut cursor = snapshot
2941            .excerpts
2942            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2943        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2944
2945        for locator in &locators {
2946            let prefix = cursor.slice(&Some(locator), Bias::Left);
2947            new_excerpts.append(prefix, ());
2948
2949            let mut excerpt = cursor.item().unwrap().clone();
2950            let old_text_len = excerpt.text_summary.len;
2951
2952            let up_line_count = if direction.should_expand_up() {
2953                line_count
2954            } else {
2955                0
2956            };
2957
2958            let start_row = excerpt
2959                .range
2960                .context
2961                .start
2962                .to_point(&excerpt.buffer)
2963                .row
2964                .saturating_sub(up_line_count);
2965            let start_point = Point::new(start_row, 0);
2966            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2967
2968            let down_line_count = if direction.should_expand_down() {
2969                line_count
2970            } else {
2971                0
2972            };
2973
2974            let mut end_point = excerpt.buffer.clip_point(
2975                excerpt.range.context.end.to_point(&excerpt.buffer)
2976                    + Point::new(down_line_count, 0),
2977                Bias::Left,
2978            );
2979            end_point.column = excerpt.buffer.line_len(end_point.row);
2980            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2981            excerpt.max_buffer_row = end_point.row;
2982
2983            excerpt.text_summary = excerpt
2984                .buffer
2985                .text_summary_for_range(excerpt.range.context.clone());
2986
2987            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2988            let old_start_offset = cursor.start().1;
2989            let new_text_len = excerpt.text_summary.len;
2990            let edit = Edit {
2991                old: old_start_offset..old_start_offset + old_text_len,
2992                new: new_start_offset..new_start_offset + new_text_len,
2993            };
2994
2995            if let Some(last_edit) = edits.last_mut() {
2996                if last_edit.old.end == edit.old.start {
2997                    last_edit.old.end = edit.old.end;
2998                    last_edit.new.end = edit.new.end;
2999                } else {
3000                    edits.push(edit);
3001                }
3002            } else {
3003                edits.push(edit);
3004            }
3005
3006            new_excerpts.push(excerpt, ());
3007
3008            cursor.next();
3009        }
3010
3011        new_excerpts.append(cursor.suffix(), ());
3012
3013        drop(cursor);
3014        snapshot.excerpts = new_excerpts;
3015
3016        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3017        if !edits.is_empty() {
3018            self.subscriptions.publish(edits);
3019        }
3020        cx.emit(Event::Edited {
3021            edited_buffer: None,
3022        });
3023        cx.emit(Event::ExcerptsExpanded { ids });
3024        cx.notify();
3025    }
3026
3027    #[ztracing::instrument(skip_all)]
3028    fn sync(&self, cx: &App) {
3029        let changed = self.buffer_changed_since_sync.replace(false);
3030        if !changed {
3031            return;
3032        }
3033        let edits = Self::sync_from_buffer_changes(
3034            &mut self.snapshot.borrow_mut(),
3035            &self.buffers,
3036            &self.diffs,
3037            cx,
3038        );
3039        if !edits.is_empty() {
3040            self.subscriptions.publish(edits);
3041        }
3042    }
3043
3044    fn sync_mut(&mut self, cx: &App) {
3045        let changed = self.buffer_changed_since_sync.replace(false);
3046        if !changed {
3047            return;
3048        }
3049        let edits =
3050            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3051
3052        if !edits.is_empty() {
3053            self.subscriptions.publish(edits);
3054        }
3055    }
3056
3057    fn sync_from_buffer_changes(
3058        snapshot: &mut MultiBufferSnapshot,
3059        buffers: &BTreeMap<BufferId, BufferState>,
3060        diffs: &HashMap<BufferId, DiffState>,
3061        cx: &App,
3062    ) -> Vec<Edit<MultiBufferOffset>> {
3063        let MultiBufferSnapshot {
3064            excerpts,
3065            buffer_locators: _,
3066            diffs: buffer_diff,
3067            diff_transforms: _,
3068            non_text_state_update_count,
3069            edit_count,
3070            is_dirty,
3071            has_deleted_file,
3072            has_conflict,
3073            has_inverted_diff: _,
3074            singleton: _,
3075            excerpt_ids: _,
3076            replaced_excerpts: _,
3077            trailing_excerpt_update_count: _,
3078            all_diff_hunks_expanded: _,
3079            show_deleted_hunks: _,
3080            use_extended_diff_range: _,
3081            show_headers: _,
3082        } = snapshot;
3083        *is_dirty = false;
3084        *has_deleted_file = false;
3085        *has_conflict = false;
3086
3087        if !diffs.is_empty() {
3088            let mut diffs_to_add = Vec::new();
3089            for (id, diff) in diffs {
3090                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3091                // and use the diff hunk base text ranges to compute diff transforms.
3092                // Those base text ranges are usize, so make sure if the base text changed
3093                // we also update the diff snapshot so that we don't use stale offsets
3094                if buffer_diff.get(id).is_none_or(|existing_diff| {
3095                    if !existing_diff.is_inverted {
3096                        return false;
3097                    }
3098                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3099                    base_text.remote_id() != existing_diff.base_text().remote_id()
3100                        || base_text
3101                            .version()
3102                            .changed_since(existing_diff.base_text().version())
3103                }) {
3104                    if diffs_to_add.capacity() == 0 {
3105                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3106                        // meaning re-allocations will be fairly expensive
3107                        diffs_to_add.reserve(diffs.len());
3108                    }
3109                    diffs_to_add.push((*id, diff.snapshot(cx)));
3110                }
3111            }
3112            buffer_diff.extend(diffs_to_add);
3113        }
3114
3115        let mut excerpts_to_edit = Vec::new();
3116        let mut non_text_state_updated = false;
3117        let mut edited = false;
3118        for buffer_state in buffers.values() {
3119            let buffer = buffer_state.buffer.read(cx);
3120            let version = buffer.version();
3121            let non_text_state_update_count = buffer.non_text_state_update_count();
3122
3123            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3124            let buffer_non_text_state_updated =
3125                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3126            if buffer_edited || buffer_non_text_state_updated {
3127                *buffer_state.last_version.borrow_mut() = version;
3128                buffer_state
3129                    .last_non_text_state_update_count
3130                    .set(non_text_state_update_count);
3131                excerpts_to_edit.extend(
3132                    buffer_state
3133                        .excerpts
3134                        .iter()
3135                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3136                );
3137            }
3138
3139            edited |= buffer_edited;
3140            non_text_state_updated |= buffer_non_text_state_updated;
3141            *is_dirty |= buffer.is_dirty();
3142            *has_deleted_file |= buffer
3143                .file()
3144                .is_some_and(|file| file.disk_state().is_deleted());
3145            *has_conflict |= buffer.has_conflict();
3146        }
3147        if edited {
3148            *edit_count += 1;
3149        }
3150        if non_text_state_updated {
3151            *non_text_state_update_count += 1;
3152        }
3153
3154        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3155
3156        let mut edits = Vec::new();
3157        let mut new_excerpts = SumTree::default();
3158        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3159
3160        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3161            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3162            let old_excerpt = cursor.item().unwrap();
3163            let buffer = buffer.read(cx);
3164            let buffer_id = buffer.remote_id();
3165            let mut new_excerpt;
3166            if buffer_edited {
3167                edits.extend(
3168                    buffer
3169                        .edits_since_in_range::<usize>(
3170                            old_excerpt.buffer.version(),
3171                            old_excerpt.range.context.clone(),
3172                        )
3173                        .map(|edit| {
3174                            let excerpt_old_start = cursor.start().1;
3175                            let excerpt_new_start =
3176                                ExcerptDimension(new_excerpts.summary().text.len);
3177                            let old_start = excerpt_old_start + edit.old.start;
3178                            let old_end = excerpt_old_start + edit.old.end;
3179                            let new_start = excerpt_new_start + edit.new.start;
3180                            let new_end = excerpt_new_start + edit.new.end;
3181                            Edit {
3182                                old: old_start..old_end,
3183                                new: new_start..new_end,
3184                            }
3185                        }),
3186                );
3187
3188                new_excerpt = Excerpt::new(
3189                    old_excerpt.id,
3190                    locator.clone(),
3191                    buffer_id,
3192                    Arc::new(buffer.snapshot()),
3193                    old_excerpt.range.clone(),
3194                    old_excerpt.has_trailing_newline,
3195                );
3196            } else {
3197                new_excerpt = old_excerpt.clone();
3198                new_excerpt.buffer = Arc::new(buffer.snapshot());
3199            }
3200
3201            new_excerpts.push(new_excerpt, ());
3202            cursor.next();
3203        }
3204        new_excerpts.append(cursor.suffix(), ());
3205
3206        drop(cursor);
3207        *excerpts = new_excerpts;
3208
3209        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3210    }
3211
3212    fn sync_diff_transforms(
3213        snapshot: &mut MultiBufferSnapshot,
3214        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3215        change_kind: DiffChangeKind,
3216    ) -> Vec<Edit<MultiBufferOffset>> {
3217        if excerpt_edits.is_empty() {
3218            return vec![];
3219        }
3220
3221        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3222        let mut old_diff_transforms = snapshot
3223            .diff_transforms
3224            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3225        let mut new_diff_transforms = SumTree::default();
3226        let mut old_expanded_hunks = HashSet::default();
3227        let mut output_edits = Vec::new();
3228        let mut output_delta = 0_isize;
3229        let mut at_transform_boundary = true;
3230        let mut end_of_current_insert = None;
3231
3232        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3233        while let Some(edit) = excerpt_edits.next() {
3234            excerpts.seek_forward(&edit.new.start, Bias::Right);
3235            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3236                excerpts.prev();
3237            }
3238
3239            // Keep any transforms that are before the edit.
3240            if at_transform_boundary {
3241                at_transform_boundary = false;
3242                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3243                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3244                if let Some(transform) = old_diff_transforms.item()
3245                    && old_diff_transforms.end().0 == edit.old.start
3246                    && old_diff_transforms.start().0 < edit.old.start
3247                {
3248                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3249                    old_diff_transforms.next();
3250                }
3251            }
3252
3253            // Compute the start of the edit in output coordinates.
3254            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3255            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3256            let edit_new_start =
3257                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3258
3259            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3260                &edit,
3261                &mut excerpts,
3262                &mut old_diff_transforms,
3263                &mut new_diff_transforms,
3264                &mut end_of_current_insert,
3265                &mut old_expanded_hunks,
3266                snapshot,
3267                change_kind,
3268            );
3269
3270            // Compute the end of the edit in output coordinates.
3271            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3272            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3273            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3274            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3275            let output_edit = Edit {
3276                old: edit_old_start..edit_old_end,
3277                new: edit_new_start..edit_new_end,
3278            };
3279
3280            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3281            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3282            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3283                output_edits.push(output_edit);
3284            }
3285
3286            // If this is the last edit that intersects the current diff transform,
3287            // then recreate the content up to the end of this transform, to prepare
3288            // for reusing additional slices of the old transforms.
3289            if excerpt_edits
3290                .peek()
3291                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3292            {
3293                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3294                    && match old_diff_transforms.item() {
3295                        Some(DiffTransform::BufferContent {
3296                            inserted_hunk_info: Some(hunk),
3297                            ..
3298                        }) => excerpts.item().is_some_and(|excerpt| {
3299                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3300                                && diff.is_inverted
3301                            {
3302                                return true;
3303                            }
3304                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3305                        }),
3306                        _ => true,
3307                    };
3308
3309                let mut excerpt_offset = edit.new.end;
3310                if !keep_next_old_transform {
3311                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3312                    old_diff_transforms.next();
3313                }
3314
3315                old_expanded_hunks.clear();
3316                Self::push_buffer_content_transform(
3317                    snapshot,
3318                    &mut new_diff_transforms,
3319                    excerpt_offset,
3320                    end_of_current_insert,
3321                );
3322                at_transform_boundary = true;
3323            }
3324        }
3325
3326        // Keep any transforms that are after the last edit.
3327        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3328
3329        // Ensure there's always at least one buffer content transform.
3330        if new_diff_transforms.is_empty() {
3331            new_diff_transforms.push(
3332                DiffTransform::BufferContent {
3333                    summary: Default::default(),
3334                    inserted_hunk_info: None,
3335                },
3336                (),
3337            );
3338        }
3339
3340        drop(old_diff_transforms);
3341        drop(excerpts);
3342        snapshot.diff_transforms = new_diff_transforms;
3343        snapshot.edit_count += 1;
3344
3345        #[cfg(any(test, feature = "test-support"))]
3346        snapshot.check_invariants();
3347        output_edits
3348    }
3349
3350    fn recompute_diff_transforms_for_edit(
3351        edit: &Edit<ExcerptOffset>,
3352        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3353        old_diff_transforms: &mut Cursor<
3354            DiffTransform,
3355            Dimensions<ExcerptOffset, MultiBufferOffset>,
3356        >,
3357        new_diff_transforms: &mut SumTree<DiffTransform>,
3358        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3359        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3360        snapshot: &MultiBufferSnapshot,
3361        change_kind: DiffChangeKind,
3362    ) -> bool {
3363        log::trace!(
3364            "recomputing diff transform for edit {:?} => {:?}",
3365            edit.old.start..edit.old.end,
3366            edit.new.start..edit.new.end
3367        );
3368
3369        // Record which hunks were previously expanded.
3370        while let Some(item) = old_diff_transforms.item() {
3371            if let Some(hunk_info) = item.hunk_info() {
3372                log::trace!(
3373                    "previously expanded hunk at {:?}",
3374                    old_diff_transforms.start()
3375                );
3376                old_expanded_hunks.insert(hunk_info);
3377            }
3378            if old_diff_transforms.end().0 > edit.old.end {
3379                break;
3380            }
3381            old_diff_transforms.next();
3382        }
3383
3384        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3385        // For inverted diffs, hunks are always shown, so we can't skip this.
3386        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3387        if old_expanded_hunks.is_empty()
3388            && change_kind == DiffChangeKind::BufferEdited
3389            && !all_diff_hunks_expanded
3390            && !snapshot.has_inverted_diff
3391        {
3392            return false;
3393        }
3394
3395        // Visit each excerpt that intersects the edit.
3396        let mut did_expand_hunks = false;
3397        while let Some(excerpt) = excerpts.item() {
3398            // Recompute the expanded hunks in the portion of the excerpt that
3399            // intersects the edit.
3400            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3401                let buffer = &excerpt.buffer;
3402                let excerpt_start = *excerpts.start();
3403                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3404                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3405                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3406                let edit_buffer_start =
3407                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3408                let edit_buffer_end =
3409                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3410                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3411
3412                if diff.is_inverted {
3413                    for hunk in diff.hunks_intersecting_base_text_range(
3414                        edit_buffer_start..edit_buffer_end,
3415                        diff.original_buffer_snapshot(),
3416                    ) {
3417                        did_expand_hunks = true;
3418                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3419                        if hunk_buffer_range.start < excerpt_buffer_start {
3420                            log::trace!("skipping hunk that starts before excerpt");
3421                            continue;
3422                        }
3423                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3424                        let hunk_excerpt_start = excerpt_start
3425                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3426                        let hunk_excerpt_end = excerpt_end
3427                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3428                        Self::push_buffer_content_transform(
3429                            snapshot,
3430                            new_diff_transforms,
3431                            hunk_excerpt_start,
3432                            *end_of_current_insert,
3433                        );
3434                        if !hunk_buffer_range.is_empty() {
3435                            let hunk_info = DiffTransformHunkInfo {
3436                                excerpt_id: excerpt.id,
3437                                hunk_start_anchor: hunk.buffer_range.start,
3438                                hunk_secondary_status: hunk.secondary_status,
3439                                is_logically_deleted: true,
3440                            };
3441                            *end_of_current_insert =
3442                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3443                        }
3444                    }
3445                } else {
3446                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3447                        ..buffer.anchor_after(edit_buffer_end);
3448                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3449                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3450                            continue;
3451                        }
3452
3453                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3454                        if hunk_buffer_range.start < excerpt_buffer_start {
3455                            log::trace!("skipping hunk that starts before excerpt");
3456                            continue;
3457                        }
3458
3459                        let hunk_info = DiffTransformHunkInfo {
3460                            excerpt_id: excerpt.id,
3461                            hunk_start_anchor: hunk.buffer_range.start,
3462                            hunk_secondary_status: hunk.secondary_status,
3463                            is_logically_deleted: false,
3464                        };
3465
3466                        let hunk_excerpt_start = excerpt_start
3467                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3468                        let hunk_excerpt_end = excerpt_end
3469                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3470
3471                        Self::push_buffer_content_transform(
3472                            snapshot,
3473                            new_diff_transforms,
3474                            hunk_excerpt_start,
3475                            *end_of_current_insert,
3476                        );
3477
3478                        // For every existing hunk, determine if it was previously expanded
3479                        // and if it should currently be expanded.
3480                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3481                        let should_expand_hunk = match &change_kind {
3482                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3483                                was_previously_expanded || all_diff_hunks_expanded
3484                            }
3485                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3486                                let intersects = hunk_buffer_range.is_empty()
3487                                    || hunk_buffer_range.end > edit_buffer_start;
3488                                if *expand {
3489                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3490                                } else {
3491                                    !intersects
3492                                        && (was_previously_expanded || all_diff_hunks_expanded)
3493                                }
3494                            }
3495                            _ => was_previously_expanded || all_diff_hunks_expanded,
3496                        };
3497
3498                        if should_expand_hunk {
3499                            did_expand_hunks = true;
3500                            log::trace!(
3501                                "expanding hunk {:?}, excerpt:{:?}",
3502                                hunk_excerpt_start..hunk_excerpt_end,
3503                                excerpt.id
3504                            );
3505
3506                            if !hunk.diff_base_byte_range.is_empty()
3507                                && hunk_buffer_range.start >= edit_buffer_start
3508                                && hunk_buffer_range.start <= excerpt_buffer_end
3509                                && snapshot.show_deleted_hunks
3510                            {
3511                                let base_text = diff.base_text();
3512                                let mut text_cursor =
3513                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3514                                let mut base_text_summary = text_cursor
3515                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3516
3517                                let mut has_trailing_newline = false;
3518                                if base_text_summary.last_line_chars > 0 {
3519                                    base_text_summary += TextSummary::newline();
3520                                    has_trailing_newline = true;
3521                                }
3522
3523                                new_diff_transforms.push(
3524                                    DiffTransform::DeletedHunk {
3525                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3526                                        summary: base_text_summary,
3527                                        buffer_id: excerpt.buffer_id,
3528                                        hunk_info,
3529                                        has_trailing_newline,
3530                                    },
3531                                    (),
3532                                );
3533                            }
3534
3535                            if !hunk_buffer_range.is_empty() {
3536                                *end_of_current_insert =
3537                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3538                            }
3539                        }
3540                    }
3541                }
3542            }
3543
3544            if excerpts.end() <= edit.new.end {
3545                excerpts.next();
3546            } else {
3547                break;
3548            }
3549        }
3550
3551        did_expand_hunks || !old_expanded_hunks.is_empty()
3552    }
3553
3554    fn append_diff_transforms(
3555        new_transforms: &mut SumTree<DiffTransform>,
3556        subtree: SumTree<DiffTransform>,
3557    ) {
3558        if let Some(DiffTransform::BufferContent {
3559            inserted_hunk_info,
3560            summary,
3561        }) = subtree.first()
3562            && Self::extend_last_buffer_content_transform(
3563                new_transforms,
3564                *inserted_hunk_info,
3565                *summary,
3566            )
3567        {
3568            let mut cursor = subtree.cursor::<()>(());
3569            cursor.next();
3570            cursor.next();
3571            new_transforms.append(cursor.suffix(), ());
3572            return;
3573        }
3574        new_transforms.append(subtree, ());
3575    }
3576
3577    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3578        if let DiffTransform::BufferContent {
3579            inserted_hunk_info: inserted_hunk_anchor,
3580            summary,
3581        } = transform
3582            && Self::extend_last_buffer_content_transform(
3583                new_transforms,
3584                inserted_hunk_anchor,
3585                summary,
3586            )
3587        {
3588            return;
3589        }
3590        new_transforms.push(transform, ());
3591    }
3592
3593    fn push_buffer_content_transform(
3594        old_snapshot: &MultiBufferSnapshot,
3595        new_transforms: &mut SumTree<DiffTransform>,
3596        end_offset: ExcerptOffset,
3597        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3598    ) {
3599        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3600            (end_offset.min(insertion_end_offset), Some(hunk_info))
3601        });
3602        let unchanged_region = [(end_offset, None)];
3603
3604        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3605        {
3606            let start_offset = new_transforms.summary().excerpt_len();
3607            if end_offset <= start_offset {
3608                continue;
3609            }
3610            let summary_to_add = old_snapshot
3611                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3612
3613            if !Self::extend_last_buffer_content_transform(
3614                new_transforms,
3615                inserted_hunk_info,
3616                summary_to_add,
3617            ) {
3618                new_transforms.push(
3619                    DiffTransform::BufferContent {
3620                        summary: summary_to_add,
3621                        inserted_hunk_info,
3622                    },
3623                    (),
3624                )
3625            }
3626        }
3627    }
3628
3629    fn extend_last_buffer_content_transform(
3630        new_transforms: &mut SumTree<DiffTransform>,
3631        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3632        summary_to_add: MBTextSummary,
3633    ) -> bool {
3634        let mut did_extend = false;
3635        new_transforms.update_last(
3636            |last_transform| {
3637                if let DiffTransform::BufferContent {
3638                    summary,
3639                    inserted_hunk_info: inserted_hunk_anchor,
3640                } = last_transform
3641                    && *inserted_hunk_anchor == new_inserted_hunk_info
3642                {
3643                    *summary += summary_to_add;
3644                    did_extend = true;
3645                }
3646            },
3647            (),
3648        );
3649        did_extend
3650    }
3651
3652    pub fn toggle_single_diff_hunk(&mut self, range: Range<Anchor>, cx: &mut Context<Self>) {
3653        let snapshot = self.snapshot(cx);
3654        let excerpt_id = range.end.excerpt_id;
3655        let point_range = range.to_point(&snapshot);
3656        let expand = !self.single_hunk_is_expanded(range, cx);
3657        let edits =
3658            self.expand_or_collapse_diff_hunks_inner([(point_range, excerpt_id)], expand, cx);
3659        if !edits.is_empty() {
3660            self.subscriptions.publish(edits);
3661        }
3662        cx.emit(Event::DiffHunksToggled);
3663        cx.emit(Event::Edited {
3664            edited_buffer: None,
3665        });
3666    }
3667}
3668
3669fn build_excerpt_ranges(
3670    ranges: impl IntoIterator<Item = Range<Point>>,
3671    context_line_count: u32,
3672    buffer_snapshot: &BufferSnapshot,
3673) -> Vec<ExcerptRange<Point>> {
3674    ranges
3675        .into_iter()
3676        .map(|range| {
3677            let start_row = range.start.row.saturating_sub(context_line_count);
3678            let start = Point::new(start_row, 0);
3679            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3680            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3681            ExcerptRange {
3682                context: start..end,
3683                primary: range,
3684            }
3685        })
3686        .collect()
3687}
3688
3689#[cfg(any(test, feature = "test-support"))]
3690impl MultiBuffer {
3691    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3692        let buffer = cx.new(|cx| Buffer::local(text, cx));
3693        cx.new(|cx| Self::singleton(buffer, cx))
3694    }
3695
3696    pub fn build_multi<const COUNT: usize>(
3697        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3698        cx: &mut gpui::App,
3699    ) -> Entity<Self> {
3700        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3701        for (text, ranges) in excerpts {
3702            let buffer = cx.new(|cx| Buffer::local(text, cx));
3703            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3704            multi.update(cx, |multi, cx| {
3705                multi.push_excerpts(buffer, excerpt_ranges, cx)
3706            });
3707        }
3708
3709        multi
3710    }
3711
3712    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3713        cx.new(|cx| Self::singleton(buffer, cx))
3714    }
3715
3716    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3717        cx.new(|cx| {
3718            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3719            let mutation_count = rng.random_range(1..=5);
3720            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3721            multibuffer
3722        })
3723    }
3724
3725    pub fn randomly_edit(
3726        &mut self,
3727        rng: &mut impl rand::Rng,
3728        edit_count: usize,
3729        cx: &mut Context<Self>,
3730    ) {
3731        use util::RandomCharIter;
3732
3733        let snapshot = self.read(cx);
3734        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3735        let mut last_end = None;
3736        for _ in 0..edit_count {
3737            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3738                break;
3739            }
3740
3741            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3742            let end =
3743                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3744            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3745            last_end = Some(end);
3746
3747            let mut range = start..end;
3748            if rng.random_bool(0.2) {
3749                mem::swap(&mut range.start, &mut range.end);
3750            }
3751
3752            let new_text_len = rng.random_range(0..10);
3753            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3754
3755            edits.push((range, new_text.into()));
3756        }
3757        log::info!("mutating multi-buffer with {:?}", edits);
3758        drop(snapshot);
3759
3760        self.edit(edits, None, cx);
3761    }
3762
3763    pub fn randomly_edit_excerpts(
3764        &mut self,
3765        rng: &mut impl rand::Rng,
3766        mutation_count: usize,
3767        cx: &mut Context<Self>,
3768    ) {
3769        use rand::prelude::*;
3770        use std::env;
3771        use util::RandomCharIter;
3772
3773        let max_excerpts = env::var("MAX_EXCERPTS")
3774            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3775            .unwrap_or(5);
3776
3777        let mut buffers = Vec::new();
3778        for _ in 0..mutation_count {
3779            if rng.random_bool(0.05) {
3780                log::info!("Clearing multi-buffer");
3781                self.clear(cx);
3782                continue;
3783            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3784                let ids = self.excerpt_ids();
3785                let mut excerpts = HashSet::default();
3786                for _ in 0..rng.random_range(0..ids.len()) {
3787                    excerpts.extend(ids.choose(rng).copied());
3788                }
3789
3790                let line_count = rng.random_range(0..5);
3791
3792                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3793
3794                self.expand_excerpts(
3795                    excerpts.iter().cloned(),
3796                    line_count,
3797                    ExpandExcerptDirection::UpAndDown,
3798                    cx,
3799                );
3800                continue;
3801            }
3802
3803            let excerpt_ids = self.excerpt_ids();
3804            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3805                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3806                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3807                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3808                    let buffer = buffers.last().unwrap().read(cx);
3809                    log::info!(
3810                        "Creating new buffer {} with text: {:?}",
3811                        buffer.remote_id(),
3812                        buffer.text()
3813                    );
3814                    buffers.last().unwrap().clone()
3815                } else {
3816                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3817                };
3818
3819                let buffer = buffer_handle.read(cx);
3820                let buffer_text = buffer.text();
3821                let ranges = (0..rng.random_range(0..5))
3822                    .map(|_| {
3823                        let end_ix =
3824                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3825                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3826                        ExcerptRange::new(start_ix..end_ix)
3827                    })
3828                    .collect::<Vec<_>>();
3829                log::info!(
3830                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3831                    buffer_handle.read(cx).remote_id(),
3832                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3833                    ranges
3834                        .iter()
3835                        .map(|r| &buffer_text[r.context.clone()])
3836                        .collect::<Vec<_>>()
3837                );
3838
3839                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3840                log::info!("Inserted with ids: {:?}", excerpt_id);
3841            } else {
3842                let remove_count = rng.random_range(1..=excerpt_ids.len());
3843                let mut excerpts_to_remove = excerpt_ids
3844                    .choose_multiple(rng, remove_count)
3845                    .cloned()
3846                    .collect::<Vec<_>>();
3847                let snapshot = self.snapshot.borrow();
3848                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3849                drop(snapshot);
3850                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3851                self.remove_excerpts(excerpts_to_remove, cx);
3852            }
3853        }
3854    }
3855
3856    pub fn randomly_mutate(
3857        &mut self,
3858        rng: &mut impl rand::Rng,
3859        mutation_count: usize,
3860        cx: &mut Context<Self>,
3861    ) {
3862        use rand::prelude::*;
3863
3864        if rng.random_bool(0.7) || self.singleton {
3865            let buffer = self
3866                .buffers
3867                .values()
3868                .choose(rng)
3869                .map(|state| state.buffer.clone());
3870
3871            if let Some(buffer) = buffer {
3872                buffer.update(cx, |buffer, cx| {
3873                    if rng.random() {
3874                        buffer.randomly_edit(rng, mutation_count, cx);
3875                    } else {
3876                        buffer.randomly_undo_redo(rng, cx);
3877                    }
3878                });
3879            } else {
3880                self.randomly_edit(rng, mutation_count, cx);
3881            }
3882        } else {
3883            self.randomly_edit_excerpts(rng, mutation_count, cx);
3884        }
3885
3886        self.check_invariants(cx);
3887    }
3888
3889    fn check_invariants(&self, cx: &App) {
3890        self.read(cx).check_invariants();
3891    }
3892}
3893
3894impl EventEmitter<Event> for MultiBuffer {}
3895
3896impl MultiBufferSnapshot {
3897    pub fn text(&self) -> String {
3898        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3899            .map(|chunk| chunk.text)
3900            .collect()
3901    }
3902
3903    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3904        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3905            .flat_map(|c| c.chars().rev())
3906    }
3907
3908    fn reversed_chunks_in_range(
3909        &self,
3910        range: Range<MultiBufferOffset>,
3911    ) -> ReversedMultiBufferChunks<'_> {
3912        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3913        cursor.seek(&range.end);
3914        let current_chunks = cursor.region().as_ref().map(|region| {
3915            let start_overshoot = range.start.saturating_sub(region.range.start);
3916            let end_overshoot = range.end - region.range.start;
3917            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3918            let start = region.buffer_range.start + start_overshoot;
3919            region.buffer.reversed_chunks_in_range(start..end)
3920        });
3921        ReversedMultiBufferChunks {
3922            cursor,
3923            current_chunks,
3924            start: range.start,
3925            offset: range.end,
3926        }
3927    }
3928
3929    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3930        let offset = position.to_offset(self);
3931        self.text_for_range(offset..self.len())
3932            .flat_map(|chunk| chunk.chars())
3933    }
3934
3935    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3936        self.chunks(range, false).map(|chunk| chunk.text)
3937    }
3938
3939    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3940        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3941            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3942    }
3943
3944    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3945    where
3946        T: ToOffset,
3947    {
3948        let position = position.to_offset(self);
3949        position == self.clip_offset(position, Bias::Left)
3950            && self
3951                .bytes_in_range(position..self.len())
3952                .flatten()
3953                .copied()
3954                .take(needle.len())
3955                .eq(needle.bytes())
3956    }
3957
3958    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3959        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3960    }
3961
3962    pub fn diff_hunks_in_range<T: ToPoint>(
3963        &self,
3964        range: Range<T>,
3965    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3966        let query_range = range.start.to_point(self)..range.end.to_point(self);
3967        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3968            let diff = self.diffs.get(&buffer.remote_id())?;
3969            let iter = if diff.is_inverted {
3970                let buffer_start = buffer.point_to_offset(buffer_range.start);
3971                let buffer_end = buffer.point_to_offset(buffer_range.end);
3972                itertools::Either::Left(
3973                    diff.hunks_intersecting_base_text_range(
3974                        buffer_start..buffer_end,
3975                        diff.original_buffer_snapshot(),
3976                    )
3977                    .map(move |hunk| (hunk, buffer, true)),
3978                )
3979            } else {
3980                let buffer_start = buffer.anchor_before(buffer_range.start);
3981                let buffer_end = buffer.anchor_after(buffer_range.end);
3982                itertools::Either::Right(
3983                    diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3984                        .map(move |hunk| (hunk, buffer, false)),
3985                )
3986            };
3987            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3988                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3989                    return None;
3990                }
3991                let range = if is_inverted {
3992                    hunk.diff_base_byte_range.to_point(&buffer)
3993                } else {
3994                    hunk.range.clone()
3995                };
3996                Some((range, (hunk, is_inverted)))
3997            }))
3998        })
3999        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
4000            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
4001            {
4002                return None;
4003            }
4004            let end_row = if range.end.column == 0 {
4005                range.end.row
4006            } else {
4007                range.end.row + 1
4008            };
4009
4010            let word_diffs =
4011                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
4012                    .then(|| {
4013                        let mut word_diffs = Vec::new();
4014
4015                        if self.show_deleted_hunks || is_inverted {
4016                            let hunk_start_offset = if is_inverted {
4017                                Anchor::in_buffer(
4018                                    excerpt.id,
4019                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
4020                                )
4021                                .to_offset(self)
4022                            } else {
4023                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
4024                                    .to_offset(self)
4025                            };
4026
4027                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
4028                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
4029                            }));
4030                        }
4031
4032                        if !is_inverted {
4033                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
4034                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
4035                            }));
4036                        }
4037                        word_diffs
4038                    })
4039                    .unwrap_or_default();
4040
4041            let buffer_range = if is_inverted {
4042                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
4043                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
4044            } else {
4045                hunk.buffer_range.clone()
4046            };
4047            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
4048                DiffHunkStatusKind::Deleted
4049            } else if hunk.diff_base_byte_range.is_empty() {
4050                DiffHunkStatusKind::Added
4051            } else {
4052                DiffHunkStatusKind::Modified
4053            };
4054            Some(MultiBufferDiffHunk {
4055                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
4056                buffer_id: excerpt.buffer_id,
4057                excerpt_id: excerpt.id,
4058                buffer_range,
4059                word_diffs,
4060                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
4061                    ..BufferOffset(hunk.diff_base_byte_range.end),
4062                status: DiffHunkStatus {
4063                    kind: status_kind,
4064                    secondary: hunk.secondary_status,
4065                },
4066            })
4067        })
4068    }
4069
4070    fn excerpts_for_range<T: ToOffset>(
4071        &self,
4072        range: Range<T>,
4073    ) -> impl Iterator<Item = &Excerpt> + '_ {
4074        let range = range.start.to_offset(self)..range.end.to_offset(self);
4075        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4076        cursor.seek(&range.start);
4077        std::iter::from_fn(move || {
4078            let region = cursor.region()?;
4079            if region.range.start > range.end
4080                || region.range.start == range.end && region.range.start > range.start
4081            {
4082                return None;
4083            }
4084            let excerpt = region.excerpt;
4085            cursor.next_excerpt_forwards();
4086            Some(excerpt)
4087        })
4088    }
4089
4090    pub fn excerpt_ids_for_range<T: ToOffset>(
4091        &self,
4092        range: Range<T>,
4093    ) -> impl Iterator<Item = ExcerptId> + '_ {
4094        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4095    }
4096
4097    pub fn buffer_ids_for_range<T: ToOffset>(
4098        &self,
4099        range: Range<T>,
4100    ) -> impl Iterator<Item = BufferId> + '_ {
4101        self.excerpts_for_range(range)
4102            .map(|excerpt| excerpt.buffer_id)
4103    }
4104
4105    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4106    ///
4107    /// The passed in anchors must be ordered.
4108    pub fn text_anchors_to_visible_anchors(
4109        &self,
4110        anchors: impl IntoIterator<Item = text::Anchor>,
4111    ) -> Vec<Option<Anchor>> {
4112        let anchors = anchors.into_iter();
4113        let mut result = Vec::with_capacity(anchors.size_hint().0);
4114        let mut anchors = anchors.peekable();
4115        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4116        'anchors: while let Some(anchor) = anchors.peek() {
4117            let Some(buffer_id) = anchor.buffer_id else {
4118                anchors.next();
4119                result.push(None);
4120                continue 'anchors;
4121            };
4122            let mut same_buffer_anchors =
4123                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4124
4125            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4126                let Some(mut next) = same_buffer_anchors.next() else {
4127                    continue 'anchors;
4128                };
4129                'excerpts: for locator in locators.iter() {
4130                    if cursor.seek_forward(&Some(locator), Bias::Left)
4131                        && let Some(excerpt) = cursor.item()
4132                    {
4133                        loop {
4134                            // anchor is before the first excerpt
4135                            if excerpt
4136                                .range
4137                                .context
4138                                .start
4139                                .cmp(&next, &excerpt.buffer)
4140                                .is_gt()
4141                            {
4142                                // so we skip it and try the next anchor
4143                                result.push(None);
4144                                match same_buffer_anchors.next() {
4145                                    Some(anchor) => next = anchor,
4146                                    None => continue 'anchors,
4147                                }
4148                            // anchor is within the excerpt
4149                            } else if excerpt
4150                                .range
4151                                .context
4152                                .end
4153                                .cmp(&next, &excerpt.buffer)
4154                                .is_ge()
4155                            {
4156                                // record it and all following anchors that are within
4157                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4158                                result.extend(
4159                                    same_buffer_anchors
4160                                        .peeking_take_while(|a| {
4161                                            excerpt
4162                                                .range
4163                                                .context
4164                                                .end
4165                                                .cmp(a, &excerpt.buffer)
4166                                                .is_ge()
4167                                        })
4168                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4169                                );
4170                                match same_buffer_anchors.next() {
4171                                    Some(anchor) => next = anchor,
4172                                    None => continue 'anchors,
4173                                }
4174                            // anchor is after the excerpt, try the next one
4175                            } else {
4176                                continue 'excerpts;
4177                            }
4178                        }
4179                    }
4180                }
4181                // account for `next`
4182                result.push(None);
4183            }
4184            result.extend(same_buffer_anchors.map(|_| None));
4185        }
4186
4187        result
4188    }
4189
4190    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4191        &self,
4192        ranges: impl Iterator<Item = Range<T>>,
4193    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4194        ranges.flat_map(|range| {
4195            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4196                .into_iter()
4197        })
4198    }
4199
4200    pub fn range_to_buffer_ranges<R, T>(
4201        &self,
4202        range: R,
4203    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4204    where
4205        R: RangeBounds<T>,
4206        T: ToOffset,
4207    {
4208        self.range_to_buffer_ranges_with_context(range)
4209            .into_iter()
4210            .map(|(buffer, range, id, _context)| (buffer, range, id))
4211            .collect()
4212    }
4213
4214    pub fn range_to_buffer_ranges_with_context<R, T>(
4215        &self,
4216        range: R,
4217    ) -> Vec<(
4218        &BufferSnapshot,
4219        Range<BufferOffset>,
4220        ExcerptId,
4221        Range<text::Anchor>,
4222    )>
4223    where
4224        R: RangeBounds<T>,
4225        T: ToOffset,
4226    {
4227        let start = match range.start_bound() {
4228            Bound::Included(start) => start.to_offset(self),
4229            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4230            Bound::Unbounded => MultiBufferOffset::ZERO,
4231        };
4232        let end_bound = match range.end_bound() {
4233            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4234            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4235            Bound::Unbounded => Bound::Unbounded,
4236        };
4237        let bounds = (Bound::Included(start), end_bound);
4238
4239        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4240        cursor.seek(&start);
4241
4242        let mut result: Vec<(
4243            &BufferSnapshot,
4244            Range<BufferOffset>,
4245            ExcerptId,
4246            Range<text::Anchor>,
4247        )> = Vec::new();
4248        while let Some(region) = cursor.region() {
4249            let dominated_by_end_bound = match end_bound {
4250                Bound::Included(end) => region.range.start > end,
4251                Bound::Excluded(end) => region.range.start >= end,
4252                Bound::Unbounded => false,
4253            };
4254            if dominated_by_end_bound {
4255                break;
4256            }
4257            if region.is_main_buffer {
4258                let start_overshoot = start.saturating_sub(region.range.start);
4259                let end_offset = match end_bound {
4260                    Bound::Included(end) | Bound::Excluded(end) => end,
4261                    Bound::Unbounded => region.range.end,
4262                };
4263                let end_overshoot = end_offset.saturating_sub(region.range.start);
4264                let start = region
4265                    .buffer_range
4266                    .end
4267                    .min(region.buffer_range.start + start_overshoot);
4268                let end = region
4269                    .buffer_range
4270                    .end
4271                    .min(region.buffer_range.start + end_overshoot);
4272                let context = region.excerpt.range.context.clone();
4273                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4274                    *excerpt_id == region.excerpt.id && prev_range.end == start
4275                }) {
4276                    prev.1.end = end;
4277                } else {
4278                    result.push((region.buffer, start..end, region.excerpt.id, context));
4279                }
4280            }
4281            cursor.next();
4282        }
4283
4284        if let Some(excerpt) = cursor.excerpt() {
4285            let dominated_by_prev_excerpt =
4286                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4287            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4288                let excerpt_position = self.len();
4289                if bounds.contains(&excerpt_position) {
4290                    let buffer_offset =
4291                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4292                    let context = excerpt.range.context.clone();
4293                    result.push((
4294                        &excerpt.buffer,
4295                        buffer_offset..buffer_offset,
4296                        excerpt.id,
4297                        context,
4298                    ));
4299                }
4300            }
4301        }
4302
4303        result
4304    }
4305
4306    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4307        &self,
4308        range: Range<T>,
4309    ) -> impl Iterator<
4310        Item = (
4311            &BufferSnapshot,
4312            Range<BufferOffset>,
4313            ExcerptId,
4314            Option<Anchor>,
4315        ),
4316    > + '_ {
4317        let start = range.start.to_offset(self);
4318        let end = range.end.to_offset(self);
4319
4320        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4321        cursor.seek(&start);
4322
4323        std::iter::from_fn(move || {
4324            let region = cursor.region()?;
4325            if region.range.start > end {
4326                return None;
4327            }
4328            let start_overshoot = start.saturating_sub(region.range.start);
4329            let end_overshoot = end.saturating_sub(region.range.start);
4330            let start = region
4331                .buffer_range
4332                .end
4333                .min(region.buffer_range.start + start_overshoot);
4334            let end = region
4335                .buffer_range
4336                .end
4337                .min(region.buffer_range.start + end_overshoot);
4338
4339            let region_excerpt_id = region.excerpt.id;
4340            let deleted_hunk_anchor = if region.is_main_buffer {
4341                None
4342            } else {
4343                Some(self.anchor_before(region.range.start))
4344            };
4345            let result = (
4346                region.buffer,
4347                start..end,
4348                region_excerpt_id,
4349                deleted_hunk_anchor,
4350            );
4351            cursor.next();
4352            Some(result)
4353        })
4354    }
4355
4356    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4357    /// coordinates.
4358    ///
4359    /// The given callback will be called for every excerpt intersecting the given range. It will
4360    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4361    /// The callback should return an iterator of metadata items from that buffer, each paired
4362    /// with a buffer range.
4363    ///
4364    /// The returned iterator yields each of these metadata items, paired with its range in
4365    /// multi-buffer coordinates.
4366    fn lift_buffer_metadata<'a, MBD, M, I>(
4367        &'a self,
4368        query_range: Range<MBD>,
4369        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4370    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4371    where
4372        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4373        MBD: MultiBufferDimension
4374            + Ord
4375            + Sub<Output = MBD::TextDimension>
4376            + ops::Add<MBD::TextDimension, Output = MBD>
4377            + ops::AddAssign<MBD::TextDimension>,
4378        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4379            + ops::Add<Output = MBD::TextDimension>
4380            + AddAssign<MBD::TextDimension>
4381            + Ord,
4382    {
4383        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4384        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4385
4386        // Find the excerpt and buffer offset where the given range ends.
4387        cursor.seek(&query_range.end);
4388        let mut range_end = None;
4389        while let Some(region) = cursor.region() {
4390            if region.is_main_buffer {
4391                let mut buffer_end = region.buffer_range.start;
4392                let overshoot = if query_range.end > region.range.start {
4393                    query_range.end - region.range.start
4394                } else {
4395                    <MBD::TextDimension>::default()
4396                };
4397                buffer_end = buffer_end + overshoot;
4398                range_end = Some((region.excerpt.id, buffer_end));
4399                break;
4400            }
4401            cursor.next();
4402        }
4403
4404        cursor.seek(&query_range.start);
4405
4406        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4407            && region.range.start > MBD::default()
4408        {
4409            cursor.prev()
4410        } else if let Some(region) = cursor.region()
4411            && region.is_main_buffer
4412            && region.diff_hunk_status.is_some()
4413        {
4414            cursor.prev();
4415            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4416                cursor.next();
4417            }
4418        }
4419
4420        iter::from_fn(move || {
4421            loop {
4422                let excerpt = cursor.excerpt()?;
4423
4424                // If we have already retrieved metadata for this excerpt, continue to use it.
4425                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4426                    .as_mut()
4427                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4428                {
4429                    Some(metadata)
4430                }
4431                // Otherwise, compute the intersection of the input range with the excerpt's range,
4432                // and retrieve the metadata for the resulting range.
4433                else {
4434                    let region = cursor.region()?;
4435                    let mut buffer_start;
4436                    if region.is_main_buffer {
4437                        buffer_start = region.buffer_range.start;
4438                        if query_range.start > region.range.start {
4439                            let overshoot = query_range.start - region.range.start;
4440                            buffer_start = buffer_start + overshoot;
4441                        }
4442                        buffer_start = buffer_start.min(region.buffer_range.end);
4443                    } else {
4444                        buffer_start = cursor.main_buffer_position()?;
4445                    };
4446                    let mut buffer_end = excerpt
4447                        .range
4448                        .context
4449                        .end
4450                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4451                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4452                        && excerpt.id == end_excerpt_id
4453                    {
4454                        buffer_end = buffer_end.min(end_buffer_offset);
4455                    }
4456
4457                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4458                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4459                    })
4460                };
4461
4462                // Visit each metadata item.
4463                if let Some((metadata_buffer_range, metadata)) =
4464                    metadata_iter.and_then(Iterator::next)
4465                {
4466                    // Find the multibuffer regions that contain the start and end of
4467                    // the metadata item's range.
4468                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4469                        while let Some(region) = cursor.region() {
4470                            if (region.is_main_buffer
4471                                && (region.buffer_range.end >= metadata_buffer_range.start
4472                                    || cursor.is_at_end_of_excerpt()))
4473                                || (!region.is_main_buffer
4474                                    && region.buffer_range.start == metadata_buffer_range.start)
4475                            {
4476                                break;
4477                            }
4478                            cursor.next();
4479                        }
4480                    }
4481                    let start_region = cursor.region()?.clone();
4482                    while let Some(region) = cursor.region() {
4483                        if region.is_main_buffer
4484                            && (region.buffer_range.end > metadata_buffer_range.end
4485                                || cursor.is_at_end_of_excerpt())
4486                        {
4487                            break;
4488                        }
4489                        cursor.next();
4490                    }
4491                    let end_region = cursor.region();
4492
4493                    // Convert the metadata item's range into multibuffer coordinates.
4494                    let mut start_position = start_region.range.start;
4495                    let region_buffer_start = start_region.buffer_range.start;
4496                    if start_region.is_main_buffer
4497                        && metadata_buffer_range.start > region_buffer_start
4498                    {
4499                        start_position =
4500                            start_position + (metadata_buffer_range.start - region_buffer_start);
4501                        start_position = start_position.min(start_region.range.end);
4502                    }
4503
4504                    let mut end_position = self.max_position();
4505                    if let Some(end_region) = &end_region {
4506                        end_position = end_region.range.start;
4507                        debug_assert!(end_region.is_main_buffer);
4508                        let region_buffer_start = end_region.buffer_range.start;
4509                        if metadata_buffer_range.end > region_buffer_start {
4510                            end_position =
4511                                end_position + (metadata_buffer_range.end - region_buffer_start);
4512                        }
4513                        end_position = end_position.min(end_region.range.end);
4514                    }
4515
4516                    if start_position <= query_range.end && end_position >= query_range.start {
4517                        return Some((start_position..end_position, metadata, excerpt));
4518                    }
4519                }
4520                // When there are no more metadata items for this excerpt, move to the next excerpt.
4521                else {
4522                    current_excerpt_metadata.take();
4523                    if let Some((end_excerpt_id, _)) = range_end
4524                        && excerpt.id == end_excerpt_id
4525                    {
4526                        return None;
4527                    }
4528                    cursor.next_excerpt_forwards();
4529                }
4530            }
4531        })
4532    }
4533
4534    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4535        let offset = position.to_offset(self);
4536
4537        let mut cursor = self
4538            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4539            );
4540        cursor.seek(&DimensionPair {
4541            key: offset,
4542            value: None,
4543        });
4544        cursor.seek_to_start_of_current_excerpt();
4545        let excerpt = cursor.excerpt()?;
4546
4547        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4548        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4549        let current_position = self
4550            .anchor_before(offset)
4551            .text_anchor
4552            .to_offset(&excerpt.buffer);
4553
4554        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4555            if diff.is_inverted {
4556                for hunk in diff.hunks_intersecting_base_text_range_rev(
4557                    excerpt_start..excerpt_end,
4558                    diff.original_buffer_snapshot(),
4559                ) {
4560                    if hunk.diff_base_byte_range.end >= current_position {
4561                        continue;
4562                    }
4563                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4564                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4565                    return Some(MultiBufferRow(start.row));
4566                }
4567            } else {
4568                let excerpt_end = excerpt
4569                    .buffer
4570                    .anchor_before(excerpt_end.min(current_position));
4571                for hunk in diff.hunks_intersecting_range_rev(
4572                    excerpt.range.context.start..excerpt_end,
4573                    &excerpt.buffer,
4574                ) {
4575                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4576                    if hunk_end >= current_position {
4577                        continue;
4578                    }
4579                    let start =
4580                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4581                    return Some(MultiBufferRow(start.row));
4582                }
4583            }
4584        }
4585
4586        loop {
4587            cursor.prev_excerpt();
4588            let excerpt = cursor.excerpt()?;
4589
4590            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4591                continue;
4592            };
4593            if diff.is_inverted {
4594                let Some(hunk) = diff
4595                    .hunks_intersecting_base_text_range_rev(
4596                        excerpt.range.context.to_offset(&excerpt.buffer),
4597                        diff.original_buffer_snapshot(),
4598                    )
4599                    .next()
4600                else {
4601                    continue;
4602                };
4603                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4604                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4605                return Some(MultiBufferRow(start.row));
4606            } else {
4607                let Some(hunk) = diff
4608                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4609                    .next()
4610                else {
4611                    continue;
4612                };
4613                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4614                return Some(MultiBufferRow(start.row));
4615            }
4616        }
4617    }
4618
4619    pub fn has_diff_hunks(&self) -> bool {
4620        self.diffs.values().any(|diff| !diff.is_empty())
4621    }
4622
4623    pub fn is_inside_word<T: ToOffset>(
4624        &self,
4625        position: T,
4626        scope_context: Option<CharScopeContext>,
4627    ) -> bool {
4628        let position = position.to_offset(self);
4629        let classifier = self
4630            .char_classifier_at(position)
4631            .scope_context(scope_context);
4632        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4633        let prev_char_kind = self
4634            .reversed_chars_at(position)
4635            .next()
4636            .map(|c| classifier.kind(c));
4637        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4638    }
4639
4640    pub fn surrounding_word<T: ToOffset>(
4641        &self,
4642        start: T,
4643        scope_context: Option<CharScopeContext>,
4644    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4645        let mut start = start.to_offset(self);
4646        let mut end = start;
4647        let mut next_chars = self.chars_at(start).peekable();
4648        let mut prev_chars = self.reversed_chars_at(start).peekable();
4649
4650        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4651
4652        let word_kind = cmp::max(
4653            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4654            next_chars.peek().copied().map(|c| classifier.kind(c)),
4655        );
4656
4657        for ch in prev_chars {
4658            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4659                start -= ch.len_utf8();
4660            } else {
4661                break;
4662            }
4663        }
4664
4665        for ch in next_chars {
4666            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4667                end += ch.len_utf8();
4668            } else {
4669                break;
4670            }
4671        }
4672
4673        (start..end, word_kind)
4674    }
4675
4676    pub fn char_kind_before<T: ToOffset>(
4677        &self,
4678        start: T,
4679        scope_context: Option<CharScopeContext>,
4680    ) -> Option<CharKind> {
4681        let start = start.to_offset(self);
4682        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4683        self.reversed_chars_at(start)
4684            .next()
4685            .map(|ch| classifier.kind(ch))
4686    }
4687
4688    pub fn is_singleton(&self) -> bool {
4689        self.singleton
4690    }
4691
4692    pub fn as_singleton(&self) -> Option<(ExcerptId, BufferId, &BufferSnapshot)> {
4693        if self.singleton {
4694            self.excerpts
4695                .iter()
4696                .next()
4697                .map(|e| (e.id, e.buffer_id, &*e.buffer))
4698        } else {
4699            None
4700        }
4701    }
4702
4703    pub fn len(&self) -> MultiBufferOffset {
4704        self.diff_transforms.summary().output.len
4705    }
4706
4707    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4708        MBD::from_summary(&self.text_summary())
4709    }
4710
4711    pub fn is_empty(&self) -> bool {
4712        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4713    }
4714
4715    pub fn widest_line_number(&self) -> u32 {
4716        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4717        self.excerpts.summary().widest_line_number + 1
4718    }
4719
4720    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4721        let range = range.start.to_offset(self)..range.end.to_offset(self);
4722        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4723        excerpts.seek(&range.start);
4724
4725        let mut chunk;
4726        let mut has_trailing_newline;
4727        let excerpt_bytes;
4728        if let Some(region) = excerpts.region() {
4729            let mut bytes = region.buffer.bytes_in_range(
4730                region.buffer_range.start + (range.start - region.range.start)
4731                    ..(region.buffer_range.start + (range.end - region.range.start))
4732                        .min(region.buffer_range.end),
4733            );
4734            chunk = bytes.next().unwrap_or(&[][..]);
4735            excerpt_bytes = Some(bytes);
4736            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4737            if chunk.is_empty() && has_trailing_newline {
4738                chunk = b"\n";
4739                has_trailing_newline = false;
4740            }
4741        } else {
4742            chunk = &[][..];
4743            excerpt_bytes = None;
4744            has_trailing_newline = false;
4745        };
4746
4747        MultiBufferBytes {
4748            range,
4749            cursor: excerpts,
4750            excerpt_bytes,
4751            has_trailing_newline,
4752            chunk,
4753        }
4754    }
4755
4756    pub fn reversed_bytes_in_range<T: ToOffset>(
4757        &self,
4758        range: Range<T>,
4759    ) -> ReversedMultiBufferBytes<'_> {
4760        let range = range.start.to_offset(self)..range.end.to_offset(self);
4761        let mut chunks = self.reversed_chunks_in_range(range.clone());
4762        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4763        ReversedMultiBufferBytes {
4764            range,
4765            chunks,
4766            chunk,
4767        }
4768    }
4769
4770    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4771        let mut cursor = self.cursor::<Point, Point>();
4772        cursor.seek(&Point::new(start_row.0, 0));
4773        let mut result = MultiBufferRows {
4774            point: Point::new(0, 0),
4775            is_empty: self.excerpts.is_empty(),
4776            is_singleton: self.is_singleton(),
4777            cursor,
4778        };
4779        result.seek(start_row);
4780        result
4781    }
4782
4783    pub fn chunks<T: ToOffset>(
4784        &self,
4785        range: Range<T>,
4786        language_aware: bool,
4787    ) -> MultiBufferChunks<'_> {
4788        let mut chunks = MultiBufferChunks {
4789            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4790                ..ExcerptDimension(MultiBufferOffset::ZERO),
4791            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4792            excerpts: self.excerpts.cursor(()),
4793            diff_transforms: self.diff_transforms.cursor(()),
4794            diffs: &self.diffs,
4795            diff_base_chunks: None,
4796            excerpt_chunks: None,
4797            buffer_chunk: None,
4798            language_aware,
4799        };
4800        let range = range.start.to_offset(self)..range.end.to_offset(self);
4801        chunks.seek(range);
4802        chunks
4803    }
4804
4805    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4806        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4807    }
4808
4809    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4810        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4811    }
4812
4813    pub fn clip_offset_utf16(
4814        &self,
4815        offset: MultiBufferOffsetUtf16,
4816        bias: Bias,
4817    ) -> MultiBufferOffsetUtf16 {
4818        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4819    }
4820
4821    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4822        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4823            buffer.clip_point_utf16(Unclipped(point), bias)
4824        })
4825    }
4826
4827    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4828        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4829    }
4830
4831    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4832        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4833    }
4834
4835    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4836        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4837    }
4838
4839    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4840        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4841    }
4842
4843    #[instrument(skip_all)]
4844    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4845        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4846    }
4847
4848    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4849        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4850    }
4851
4852    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4853        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4854    }
4855
4856    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4857        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4858    }
4859
4860    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4861        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4862    }
4863
4864    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4865        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4866    }
4867
4868    fn clip_dimension<MBD, BD>(
4869        &self,
4870        position: MBD,
4871        bias: Bias,
4872        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4873    ) -> MBD
4874    where
4875        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4876        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4877    {
4878        let mut cursor = self.cursor::<MBD, BD>();
4879        cursor.seek(&position);
4880        if let Some(region) = cursor.region() {
4881            if position >= region.range.end {
4882                return region.range.end;
4883            }
4884            let overshoot = position - region.range.start;
4885            let mut buffer_position = region.buffer_range.start;
4886            buffer_position += overshoot;
4887            let clipped_buffer_position =
4888                clip_buffer_position(region.buffer, buffer_position, bias);
4889            let mut position = region.range.start;
4890            position += clipped_buffer_position - region.buffer_range.start;
4891            position
4892        } else {
4893            self.max_position()
4894        }
4895    }
4896
4897    #[instrument(skip_all)]
4898    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4899        &self,
4900        key: MBR1,
4901        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4902    ) -> MBR2
4903    where
4904        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4905        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4906        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4907        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4908    {
4909        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4910        cursor.seek(&DimensionPair { key, value: None });
4911        if let Some(region) = cursor.region() {
4912            if key >= region.range.end.key {
4913                return region.range.end.value.unwrap();
4914            }
4915            let start_key = region.range.start.key;
4916            let start_value = region.range.start.value.unwrap();
4917            let buffer_start_key = region.buffer_range.start.key;
4918            let buffer_start_value = region.buffer_range.start.value.unwrap();
4919            let mut buffer_key = buffer_start_key;
4920            buffer_key += key - start_key;
4921            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4922            let mut result = start_value;
4923            result += buffer_value - buffer_start_value;
4924            result
4925        } else {
4926            self.max_position()
4927        }
4928    }
4929
4930    pub fn point_to_buffer_offset<T: ToOffset>(
4931        &self,
4932        point: T,
4933    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4934        let offset = point.to_offset(self);
4935        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4936        cursor.seek(&offset);
4937        let region = cursor.region()?;
4938        let overshoot = offset - region.range.start;
4939        let buffer_offset = region.buffer_range.start + overshoot;
4940        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4941            && region.has_trailing_newline
4942            && !region.is_main_buffer
4943        {
4944            let main_buffer_position = cursor.main_buffer_position()?;
4945            let buffer_snapshot = &cursor.excerpt()?.buffer;
4946            return Some((buffer_snapshot, main_buffer_position));
4947        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4948            return None;
4949        }
4950        Some((region.buffer, buffer_offset))
4951    }
4952
4953    pub fn point_to_buffer_point(
4954        &self,
4955        point: Point,
4956    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4957        let mut cursor = self.cursor::<Point, Point>();
4958        cursor.seek(&point);
4959        let region = cursor.region()?;
4960        let overshoot = point - region.range.start;
4961        let buffer_point = region.buffer_range.start + overshoot;
4962        let excerpt = cursor.excerpt()?;
4963        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4964            && region.has_trailing_newline
4965            && !region.is_main_buffer
4966        {
4967            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4968        } else if buffer_point > region.buffer.max_point() {
4969            return None;
4970        }
4971        Some((region.buffer, buffer_point, excerpt.id))
4972    }
4973
4974    pub fn suggested_indents(
4975        &self,
4976        rows: impl IntoIterator<Item = u32>,
4977        cx: &App,
4978    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4979        let mut result = BTreeMap::new();
4980        self.suggested_indents_callback(
4981            rows,
4982            &mut |row, indent| {
4983                result.insert(row, indent);
4984                ControlFlow::Continue(())
4985            },
4986            cx,
4987        );
4988        result
4989    }
4990
4991    // move this to be a generator once those are a thing
4992    pub fn suggested_indents_callback(
4993        &self,
4994        rows: impl IntoIterator<Item = u32>,
4995        cb: &mut dyn FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4996        cx: &App,
4997    ) {
4998        let mut rows_for_excerpt = Vec::new();
4999        let mut cursor = self.cursor::<Point, Point>();
5000        let mut rows = rows.into_iter().peekable();
5001        let mut prev_row = u32::MAX;
5002        let mut prev_language_indent_size = IndentSize::default();
5003
5004        while let Some(row) = rows.next() {
5005            cursor.seek(&Point::new(row, 0));
5006            let Some(region) = cursor.region() else {
5007                continue;
5008            };
5009
5010            // Retrieve the language and indent size once for each disjoint region being indented.
5011            let single_indent_size = if row.saturating_sub(1) == prev_row {
5012                prev_language_indent_size
5013            } else {
5014                region
5015                    .buffer
5016                    .language_indent_size_at(Point::new(row, 0), cx)
5017            };
5018            prev_language_indent_size = single_indent_size;
5019            prev_row = row;
5020
5021            let start_buffer_row = region.buffer_range.start.row;
5022            let start_multibuffer_row = region.range.start.row;
5023            let end_multibuffer_row = region.range.end.row;
5024
5025            rows_for_excerpt.push(row);
5026            while let Some(next_row) = rows.peek().copied() {
5027                if end_multibuffer_row > next_row {
5028                    rows_for_excerpt.push(next_row);
5029                    rows.next();
5030                } else {
5031                    break;
5032                }
5033            }
5034
5035            let buffer_rows = rows_for_excerpt
5036                .drain(..)
5037                .map(|row| start_buffer_row + row - start_multibuffer_row);
5038            let buffer_indents = region
5039                .buffer
5040                .suggested_indents(buffer_rows, single_indent_size);
5041            for (row, indent) in buffer_indents {
5042                if cb(
5043                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
5044                    indent,
5045                )
5046                .is_break()
5047                {
5048                    return;
5049                }
5050            }
5051        }
5052    }
5053
5054    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
5055        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5056            let mut size = buffer.indent_size_for_line(range.start.row);
5057            size.len = size
5058                .len
5059                .min(range.end.column)
5060                .saturating_sub(range.start.column);
5061            size
5062        } else {
5063            IndentSize::spaces(0)
5064        }
5065    }
5066
5067    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5068        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5069            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5070        } else {
5071            LineIndent::spaces(0)
5072        }
5073    }
5074
5075    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5076        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5077
5078        if self.language_settings(cx).extend_comment_on_newline
5079            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5080        {
5081            let delimiters = language_scope.line_comment_prefixes();
5082            for delimiter in delimiters {
5083                if *self
5084                    .chars_at(Point::new(row.0, indent.len() as u32))
5085                    .take(delimiter.chars().count())
5086                    .collect::<String>()
5087                    .as_str()
5088                    == **delimiter
5089                {
5090                    indent.push_str(delimiter);
5091                    break;
5092                }
5093            }
5094        }
5095
5096        indent
5097    }
5098
5099    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5100    where
5101        T: ToOffset,
5102    {
5103        for char in self.reversed_chars_at(position) {
5104            if !char.is_whitespace() {
5105                return false;
5106            }
5107            if char == '\n' {
5108                return true;
5109            }
5110        }
5111        true
5112    }
5113
5114    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5115        while row.0 > 0 {
5116            row.0 -= 1;
5117            if !self.is_line_blank(row) {
5118                return Some(row);
5119            }
5120        }
5121        None
5122    }
5123
5124    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5125        if let Some((_, range)) = self.buffer_line_for_row(row) {
5126            range.end.column - range.start.column
5127        } else {
5128            0
5129        }
5130    }
5131
5132    pub fn buffer_line_for_row(
5133        &self,
5134        row: MultiBufferRow,
5135    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5136        let mut cursor = self.cursor::<Point, Point>();
5137        let point = Point::new(row.0, 0);
5138        cursor.seek(&point);
5139        let region = cursor.region()?;
5140        let overshoot = point.min(region.range.end) - region.range.start;
5141        let buffer_point = region.buffer_range.start + overshoot;
5142        if buffer_point.row > region.buffer_range.end.row {
5143            return None;
5144        }
5145        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5146        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5147            .min(region.buffer_range.end);
5148        Some((region.buffer, line_start..line_end))
5149    }
5150
5151    pub fn max_point(&self) -> Point {
5152        self.text_summary().lines
5153    }
5154
5155    pub fn max_row(&self) -> MultiBufferRow {
5156        MultiBufferRow(self.text_summary().lines.row)
5157    }
5158
5159    pub fn text_summary(&self) -> MBTextSummary {
5160        self.diff_transforms.summary().output
5161    }
5162
5163    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5164    where
5165        MBD: MultiBufferDimension + AddAssign,
5166        O: ToOffset,
5167    {
5168        let range = range.start.to_offset(self)..range.end.to_offset(self);
5169        let mut cursor = self
5170            .diff_transforms
5171            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5172        cursor.seek(&range.start, Bias::Right);
5173
5174        let Some(first_transform) = cursor.item() else {
5175            return MBD::from_summary(&MBTextSummary::default());
5176        };
5177
5178        let diff_transform_start = cursor.start().0;
5179        let diff_transform_end = cursor.end().0;
5180        let diff_start = range.start;
5181        let start_overshoot = diff_start - diff_transform_start;
5182        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5183
5184        let mut result = match first_transform {
5185            DiffTransform::BufferContent { .. } => {
5186                let excerpt_start = cursor.start().1 + start_overshoot;
5187                let excerpt_end = cursor.start().1 + end_overshoot;
5188                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5189            }
5190            DiffTransform::DeletedHunk {
5191                buffer_id,
5192                base_text_byte_range,
5193                has_trailing_newline,
5194                ..
5195            } => {
5196                let buffer_start = base_text_byte_range.start + start_overshoot;
5197                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5198                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5199                    panic!("{:?} is in non-existent deleted hunk", range.start)
5200                };
5201
5202                let include_trailing_newline =
5203                    *has_trailing_newline && range.end >= diff_transform_end;
5204                if include_trailing_newline {
5205                    buffer_end -= 1;
5206                }
5207
5208                let mut summary = base_text
5209                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5210
5211                if include_trailing_newline {
5212                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5213                        &TextSummary::newline(),
5214                    ))
5215                }
5216
5217                let mut result = MBD::default();
5218                result.add_text_dim(&summary);
5219                result
5220            }
5221        };
5222        if range.end < diff_transform_end {
5223            return result;
5224        }
5225
5226        cursor.next();
5227        result.add_mb_text_summary(
5228            &cursor
5229                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5230                .0,
5231        );
5232
5233        let Some(last_transform) = cursor.item() else {
5234            return result;
5235        };
5236
5237        let overshoot = range.end - cursor.start().0;
5238        let suffix = match last_transform {
5239            DiffTransform::BufferContent { .. } => {
5240                let end = cursor.start().1 + overshoot;
5241                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5242            }
5243            DiffTransform::DeletedHunk {
5244                base_text_byte_range,
5245                buffer_id,
5246                has_trailing_newline,
5247                ..
5248            } => {
5249                let buffer_end = base_text_byte_range.start + overshoot;
5250                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5251                    panic!("{:?} is in non-existent deleted hunk", range.end)
5252                };
5253
5254                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5255                    base_text_byte_range.start..buffer_end,
5256                );
5257                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5258                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5259                        &TextSummary::from("\n"),
5260                    ))
5261                }
5262
5263                let mut result = MBD::default();
5264                result.add_text_dim(&suffix);
5265                result
5266            }
5267        };
5268
5269        result += suffix;
5270        result
5271    }
5272
5273    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5274    where
5275        MBD: MultiBufferDimension + AddAssign,
5276    {
5277        let mut summary = MBD::default();
5278        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5279        cursor.seek(&range.start, Bias::Right);
5280        if let Some(excerpt) = cursor.item() {
5281            let mut end_before_newline = cursor.end();
5282            if excerpt.has_trailing_newline {
5283                end_before_newline -= 1;
5284            }
5285
5286            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5287            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5288            let end_in_excerpt =
5289                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5290            summary.add_text_dim(
5291                &excerpt
5292                    .buffer
5293                    .text_summary_for_range::<MBD::TextDimension, _>(
5294                        start_in_excerpt..end_in_excerpt,
5295                    ),
5296            );
5297
5298            if range.end > end_before_newline {
5299                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5300            }
5301
5302            cursor.next();
5303        }
5304
5305        if range.end > *cursor.start() {
5306            summary += cursor
5307                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5308                .0;
5309            if let Some(excerpt) = cursor.item() {
5310                range.end = cmp::max(*cursor.start(), range.end);
5311
5312                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5313                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5314                summary.add_text_dim(
5315                    &excerpt
5316                        .buffer
5317                        .text_summary_for_range::<MBD::TextDimension, _>(
5318                            excerpt_start..end_in_excerpt,
5319                        ),
5320                );
5321            }
5322        }
5323
5324        summary
5325    }
5326
5327    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5328    where
5329        MBD: MultiBufferDimension
5330            + Ord
5331            + Sub<Output = MBD::TextDimension>
5332            + Sub<MBD::TextDimension, Output = MBD>
5333            + AddAssign<MBD::TextDimension>
5334            + Add<MBD::TextDimension, Output = MBD>,
5335        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5336    {
5337        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5338        let locator = self.excerpt_locator_for_id(excerpt_id);
5339        let (start, _, mut item) = self
5340            .excerpts
5341            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5342        let mut start = MBD::from_summary(&start.text);
5343        if item.is_none() && excerpt_id == ExcerptId::max() {
5344            item = self.excerpts.last();
5345            if let Some(last_summary) = self.excerpts.last_summary() {
5346                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5347            }
5348        }
5349
5350        let excerpt_start_position = ExcerptDimension(start);
5351        if self.diff_transforms.is_empty() {
5352            if let Some(excerpt) = item {
5353                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5354                    return excerpt_start_position.0;
5355                }
5356                let excerpt_buffer_start = excerpt
5357                    .range
5358                    .context
5359                    .start
5360                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5361                let excerpt_buffer_end = excerpt
5362                    .range
5363                    .context
5364                    .end
5365                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5366                let buffer_summary = anchor
5367                    .text_anchor
5368                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5369                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5370                let mut position = excerpt_start_position;
5371                if summary > excerpt_buffer_start {
5372                    position += summary - excerpt_buffer_start;
5373                }
5374
5375                position.0
5376            } else {
5377                excerpt_start_position.0
5378            }
5379        } else {
5380            let mut diff_transforms_cursor = self
5381                .diff_transforms
5382                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5383            diff_transforms_cursor.next();
5384
5385            if let Some(excerpt) = item {
5386                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5387                    return self.resolve_summary_for_min_or_max_anchor(
5388                        &Anchor::min(),
5389                        excerpt_start_position,
5390                        &mut diff_transforms_cursor,
5391                    );
5392                }
5393                let excerpt_buffer_start = excerpt
5394                    .range
5395                    .context
5396                    .start
5397                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5398                let excerpt_buffer_end = excerpt
5399                    .range
5400                    .context
5401                    .end
5402                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5403                let buffer_summary = anchor
5404                    .text_anchor
5405                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5406                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5407                let mut position = excerpt_start_position;
5408                if summary > excerpt_buffer_start {
5409                    position += summary - excerpt_buffer_start;
5410                }
5411
5412                if diff_transforms_cursor.start().0 < position {
5413                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5414                }
5415                self.resolve_summary_for_anchor(
5416                    &anchor,
5417                    position,
5418                    &mut diff_transforms_cursor,
5419                    &excerpt.buffer,
5420                )
5421            } else {
5422                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5423                self.resolve_summary_for_min_or_max_anchor(
5424                    &Anchor::max(),
5425                    excerpt_start_position,
5426                    &mut diff_transforms_cursor,
5427                )
5428            }
5429        }
5430    }
5431
5432    /// Maps an anchor's excerpt-space position to its output-space position by
5433    /// walking the diff transforms. The cursor is shared across consecutive
5434    /// calls, so it may already be partway through the transform list.
5435    fn resolve_summary_for_anchor<MBD>(
5436        &self,
5437        anchor: &Anchor,
5438        excerpt_position: ExcerptDimension<MBD>,
5439        diff_transforms: &mut Cursor<
5440            DiffTransform,
5441            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5442        >,
5443        excerpt_buffer: &text::BufferSnapshot,
5444    ) -> MBD
5445    where
5446        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5447    {
5448        loop {
5449            let transform_end_position = diff_transforms.end().0;
5450            let item = diff_transforms.item();
5451            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5452
5453            // A right-biased anchor at a transform boundary belongs to the
5454            // *next* transform, so advance past the current one.
5455            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5456                diff_transforms.next();
5457                continue;
5458            }
5459
5460            let mut position = diff_transforms.start().1;
5461            match item {
5462                Some(DiffTransform::DeletedHunk {
5463                    buffer_id,
5464                    base_text_byte_range,
5465                    hunk_info,
5466                    ..
5467                }) => {
5468                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5469                        && let Some(base_text) =
5470                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5471                        && diff_base_anchor.is_valid(&base_text)
5472                    {
5473                        // The anchor carries a diff-base position — resolve it
5474                        // to a location inside the deleted hunk.
5475                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5476                        if base_text_offset >= base_text_byte_range.start
5477                            && base_text_offset <= base_text_byte_range.end
5478                        {
5479                            let position_in_hunk = base_text
5480                                .text_summary_for_range::<MBD::TextDimension, _>(
5481                                    base_text_byte_range.start..base_text_offset,
5482                                );
5483                            position.0.add_text_dim(&position_in_hunk);
5484                        } else if at_transform_end {
5485                            // diff_base offset falls outside this hunk's range;
5486                            // advance to see if the next transform is a better fit.
5487                            diff_transforms.next();
5488                            continue;
5489                        }
5490                    } else if at_transform_end
5491                        && anchor
5492                            .text_anchor
5493                            .cmp(&hunk_info.hunk_start_anchor, excerpt_buffer)
5494                            .is_gt()
5495                    {
5496                        // The anchor has no (valid) diff-base position, so it
5497                        // belongs in the buffer content, not in the deleted
5498                        // hunk. However, after an edit deletes the text between
5499                        // the hunk boundary and this anchor, both resolve to
5500                        // the same excerpt_position—landing us here on the
5501                        // DeletedHunk left behind by the shared cursor. Use the
5502                        // CRDT ordering to detect that the anchor is strictly
5503                        // *past* the hunk boundary and skip to the following
5504                        // BufferContent.
5505                        diff_transforms.next();
5506                        continue;
5507                    }
5508                }
5509                _ => {
5510                    // On a BufferContent (or no transform). If the anchor
5511                    // carries a diff_base_anchor it needs a DeletedHunk, so
5512                    // advance to find one.
5513                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5514                        diff_transforms.next();
5515                        continue;
5516                    }
5517                    let overshoot = excerpt_position - diff_transforms.start().0;
5518                    position += overshoot;
5519                }
5520            }
5521
5522            return position.0;
5523        }
5524    }
5525
5526    /// Like `resolve_summary_for_anchor` but optimized for min/max anchors.
5527    fn resolve_summary_for_min_or_max_anchor<MBD>(
5528        &self,
5529        anchor: &Anchor,
5530        excerpt_position: ExcerptDimension<MBD>,
5531        diff_transforms: &mut Cursor<
5532            DiffTransform,
5533            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5534        >,
5535    ) -> MBD
5536    where
5537        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5538    {
5539        loop {
5540            let transform_end_position = diff_transforms.end().0;
5541            let item = diff_transforms.item();
5542            let at_transform_end = transform_end_position == excerpt_position && item.is_some();
5543
5544            // A right-biased anchor at a transform boundary belongs to the
5545            // *next* transform, so advance past the current one.
5546            if anchor.text_anchor.bias == Bias::Right && at_transform_end {
5547                diff_transforms.next();
5548                continue;
5549            }
5550
5551            let mut position = diff_transforms.start().1;
5552            if let Some(DiffTransform::BufferContent { .. }) | None = item {
5553                let overshoot = excerpt_position - diff_transforms.start().0;
5554                position += overshoot;
5555            }
5556
5557            return position.0;
5558        }
5559    }
5560
5561    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5562        let mut cursor = self
5563            .excerpts
5564            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5565        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5566
5567        cursor.seek(&Some(locator), Bias::Left);
5568        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5569            cursor.prev();
5570        }
5571
5572        let mut position = cursor.start().1;
5573        if let Some(excerpt) = cursor.item()
5574            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5575        {
5576            let excerpt_buffer_start = excerpt
5577                .buffer
5578                .offset_for_anchor(&excerpt.range.context.start);
5579            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5580            let buffer_position = cmp::min(
5581                excerpt_buffer_end,
5582                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5583            );
5584            if buffer_position > excerpt_buffer_start {
5585                position += buffer_position - excerpt_buffer_start;
5586            }
5587        }
5588        position
5589    }
5590
5591    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5592        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5593            excerpt_id = *replacement;
5594        }
5595        excerpt_id
5596    }
5597
5598    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5599    where
5600        MBD: MultiBufferDimension
5601            + Ord
5602            + Sub<Output = MBD::TextDimension>
5603            + AddAssign<MBD::TextDimension>,
5604        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5605        I: 'a + IntoIterator<Item = &'a Anchor>,
5606    {
5607        let mut anchors = anchors.into_iter().peekable();
5608        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5609        let mut diff_transforms_cursor = self
5610            .diff_transforms
5611            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5612        diff_transforms_cursor.next();
5613
5614        let mut summaries = Vec::new();
5615        while let Some(anchor) = anchors.peek() {
5616            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5617
5618            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5619                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5620            });
5621
5622            let locator = self.excerpt_locator_for_id(excerpt_id);
5623            cursor.seek_forward(locator, Bias::Left);
5624            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5625                cursor.prev();
5626            }
5627
5628            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5629            if let Some(excerpt) = cursor.item() {
5630                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5631                    let position = self.resolve_summary_for_min_or_max_anchor(
5632                        &Anchor::min(),
5633                        excerpt_start_position,
5634                        &mut diff_transforms_cursor,
5635                    );
5636                    summaries.extend(excerpt_anchors.map(|_| position));
5637                    continue;
5638                }
5639                let excerpt_buffer_start = excerpt
5640                    .range
5641                    .context
5642                    .start
5643                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5644                let excerpt_buffer_end = excerpt
5645                    .range
5646                    .context
5647                    .end
5648                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5649                for (buffer_summary, anchor) in excerpt
5650                    .buffer
5651                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5652                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5653                    )
5654                {
5655                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5656                    let mut position = excerpt_start_position;
5657                    if summary > excerpt_buffer_start {
5658                        position += summary - excerpt_buffer_start;
5659                    }
5660
5661                    if diff_transforms_cursor.start().0 < position {
5662                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5663                    }
5664
5665                    summaries.push(self.resolve_summary_for_anchor(
5666                        anchor,
5667                        position,
5668                        &mut diff_transforms_cursor,
5669                        &excerpt.buffer,
5670                    ));
5671                }
5672            } else {
5673                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5674                let position = self.resolve_summary_for_min_or_max_anchor(
5675                    &Anchor::max(),
5676                    excerpt_start_position,
5677                    &mut diff_transforms_cursor,
5678                );
5679                summaries.extend(excerpt_anchors.map(|_| position));
5680            }
5681        }
5682
5683        summaries
5684    }
5685
5686    pub fn dimensions_from_points<'a, MBD>(
5687        &'a self,
5688        points: impl 'a + IntoIterator<Item = Point>,
5689    ) -> impl 'a + Iterator<Item = MBD>
5690    where
5691        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5692    {
5693        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5694        cursor.seek(&DimensionPair {
5695            key: Point::default(),
5696            value: None,
5697        });
5698        let mut points = points.into_iter();
5699        iter::from_fn(move || {
5700            let point = points.next()?;
5701
5702            cursor.seek_forward(&DimensionPair {
5703                key: point,
5704                value: None,
5705            });
5706
5707            if let Some(region) = cursor.region() {
5708                let overshoot = point - region.range.start.key;
5709                let buffer_point = region.buffer_range.start + overshoot;
5710                let mut position = region.range.start.value.unwrap();
5711                position.add_text_dim(
5712                    &region
5713                        .buffer
5714                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5715                );
5716                if point == region.range.end.key && region.has_trailing_newline {
5717                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5718                }
5719                Some(position)
5720            } else {
5721                Some(MBD::from_summary(&self.text_summary()))
5722            }
5723        })
5724    }
5725
5726    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5727    where
5728        I: 'a + IntoIterator<Item = &'a Anchor>,
5729    {
5730        let mut anchors = anchors.into_iter().enumerate().peekable();
5731        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5732        cursor.next();
5733
5734        let mut result = Vec::new();
5735
5736        while let Some((_, anchor)) = anchors.peek() {
5737            let old_excerpt_id = anchor.excerpt_id;
5738
5739            // Find the location where this anchor's excerpt should be.
5740            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5741            cursor.seek_forward(&Some(old_locator), Bias::Left);
5742
5743            let next_excerpt = cursor.item();
5744            let prev_excerpt = cursor.prev_item();
5745
5746            // Process all of the anchors for this excerpt.
5747            while let Some((anchor_ix, &anchor)) =
5748                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5749            {
5750                let mut anchor = anchor;
5751
5752                // Leave min and max anchors unchanged if invalid or
5753                // if the old excerpt still exists at this location
5754                let mut kept_position = next_excerpt
5755                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5756                    || old_excerpt_id == ExcerptId::max()
5757                    || old_excerpt_id == ExcerptId::min();
5758
5759                // If the old excerpt no longer exists at this location, then attempt to
5760                // find an equivalent position for this anchor in an adjacent excerpt.
5761                if !kept_position {
5762                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5763                        if excerpt.contains(&anchor) {
5764                            anchor.excerpt_id = excerpt.id;
5765                            kept_position = true;
5766                            break;
5767                        }
5768                    }
5769                }
5770
5771                // If there's no adjacent excerpt that contains the anchor's position,
5772                // then report that the anchor has lost its position.
5773                if !kept_position {
5774                    anchor = if let Some(excerpt) = next_excerpt {
5775                        let mut text_anchor = excerpt
5776                            .range
5777                            .context
5778                            .start
5779                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5780                        if text_anchor
5781                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5782                            .is_gt()
5783                        {
5784                            text_anchor = excerpt.range.context.end;
5785                        }
5786                        Anchor::in_buffer(excerpt.id, text_anchor)
5787                    } else if let Some(excerpt) = prev_excerpt {
5788                        let mut text_anchor = excerpt
5789                            .range
5790                            .context
5791                            .end
5792                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5793                        if text_anchor
5794                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5795                            .is_lt()
5796                        {
5797                            text_anchor = excerpt.range.context.start;
5798                        }
5799                        Anchor::in_buffer(excerpt.id, text_anchor)
5800                    } else if anchor.text_anchor.bias == Bias::Left {
5801                        Anchor::min()
5802                    } else {
5803                        Anchor::max()
5804                    };
5805                }
5806
5807                result.push((anchor_ix, anchor, kept_position));
5808            }
5809        }
5810        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5811        result
5812    }
5813
5814    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5815        self.anchor_at(position, Bias::Left)
5816    }
5817
5818    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5819        self.anchor_at(position, Bias::Right)
5820    }
5821
5822    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5823        let offset = position.to_offset(self);
5824
5825        // Find the given position in the diff transforms. Determine the corresponding
5826        // offset in the excerpts, and whether the position is within a deleted hunk.
5827        let mut diff_transforms = self
5828            .diff_transforms
5829            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5830        diff_transforms.seek(&offset, Bias::Right);
5831
5832        if offset == diff_transforms.start().0
5833            && bias == Bias::Left
5834            && let Some(prev_item) = diff_transforms.prev_item()
5835            && let DiffTransform::DeletedHunk { .. } = prev_item
5836        {
5837            diff_transforms.prev();
5838        }
5839        let offset_in_transform = offset - diff_transforms.start().0;
5840        let mut excerpt_offset = diff_transforms.start().1;
5841        let mut diff_base_anchor = None;
5842        if let Some(DiffTransform::DeletedHunk {
5843            buffer_id,
5844            base_text_byte_range,
5845            has_trailing_newline,
5846            ..
5847        }) = diff_transforms.item()
5848        {
5849            let diff = self.diffs.get(buffer_id).expect("missing diff");
5850            if offset_in_transform > base_text_byte_range.len() {
5851                debug_assert!(*has_trailing_newline);
5852                bias = Bias::Right;
5853            } else {
5854                diff_base_anchor = Some(
5855                    diff.base_text()
5856                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5857                );
5858                bias = Bias::Left;
5859            }
5860        } else {
5861            excerpt_offset += MultiBufferOffset(offset_in_transform);
5862        };
5863
5864        let mut excerpts = self
5865            .excerpts
5866            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5867        excerpts.seek(&excerpt_offset, Bias::Right);
5868        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5869            excerpts.prev();
5870        }
5871        if let Some(excerpt) = excerpts.item() {
5872            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5873            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5874                overshoot -= 1;
5875                bias = Bias::Right;
5876            }
5877
5878            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5879            let text_anchor =
5880                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5881            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5882            match diff_base_anchor {
5883                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5884                None => anchor,
5885            }
5886        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5887        {
5888            Anchor::min()
5889        } else {
5890            Anchor::max()
5891        }
5892    }
5893
5894    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5895    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5896        let (excerpt, buffer, _) = self.as_singleton()?;
5897        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5898            Some(Anchor::in_buffer(excerpt, text_anchor))
5899        } else {
5900            None
5901        }
5902    }
5903
5904    /// Returns an anchor for the given excerpt and text anchor,
5905    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5906    pub fn anchor_range_in_excerpt(
5907        &self,
5908        excerpt_id: ExcerptId,
5909        text_anchor: Range<text::Anchor>,
5910    ) -> Option<Range<Anchor>> {
5911        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5912
5913        Some(
5914            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5915                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5916        )
5917    }
5918
5919    /// Returns an anchor for the given excerpt and text anchor,
5920    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5921    pub fn anchor_in_excerpt(
5922        &self,
5923        excerpt_id: ExcerptId,
5924        text_anchor: text::Anchor,
5925    ) -> Option<Anchor> {
5926        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5927        Self::anchor_in_excerpt_(excerpt, text_anchor)
5928    }
5929
5930    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5931    pub fn anchors_in_excerpt(
5932        &self,
5933        excerpt_id: ExcerptId,
5934        text_anchors: impl IntoIterator<Item = text::Anchor>,
5935    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5936        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5937        Some(
5938            text_anchors
5939                .into_iter()
5940                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5941        )
5942    }
5943
5944    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5945        match text_anchor.buffer_id {
5946            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5947            Some(_) => return None,
5948            None if text_anchor.is_max() || text_anchor.is_min() => {
5949                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5950            }
5951            None => return None,
5952        }
5953
5954        let context = &excerpt.range.context;
5955        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5956            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5957        {
5958            return None;
5959        }
5960
5961        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5962    }
5963
5964    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5965        Some(self.excerpt(excerpt_id)?.range.context.clone())
5966    }
5967
5968    pub fn excerpt_range_for_excerpt(
5969        &self,
5970        excerpt_id: ExcerptId,
5971    ) -> Option<ExcerptRange<text::Anchor>> {
5972        Some(self.excerpt(excerpt_id)?.range.clone())
5973    }
5974
5975    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5976        if anchor.is_min() || anchor.is_max() {
5977            // todo(lw): should be `!self.is_empty()`
5978            true
5979        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5980            excerpt.buffer.can_resolve(&anchor.text_anchor)
5981        } else {
5982            false
5983        }
5984    }
5985
5986    pub fn excerpts(
5987        &self,
5988    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5989        self.excerpts
5990            .iter()
5991            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5992    }
5993
5994    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5995    where
5996        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5997        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5998    {
5999        let excerpts = self.excerpts.cursor(());
6000        let diff_transforms = self.diff_transforms.cursor(());
6001        MultiBufferCursor {
6002            excerpts,
6003            diff_transforms,
6004            diffs: &self.diffs,
6005            cached_region: OnceCell::new(),
6006        }
6007    }
6008
6009    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
6010        let start_locator = self.excerpt_locator_for_id(excerpt_id);
6011        let mut excerpts = self
6012            .excerpts
6013            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
6014        excerpts.seek(&Some(start_locator), Bias::Left);
6015        excerpts.prev();
6016
6017        let mut diff_transforms = self
6018            .diff_transforms
6019            .cursor::<DiffTransforms<MultiBufferOffset>>(());
6020        diff_transforms.seek(&excerpts.start().1, Bias::Left);
6021        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
6022            diff_transforms.next();
6023        }
6024
6025        let excerpt = excerpts.item()?;
6026        Some(MultiBufferExcerpt {
6027            excerpt,
6028            offset: diff_transforms.start().output_dimension.0,
6029            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
6030            excerpt_offset: excerpts.start().1,
6031            diff_transforms,
6032        })
6033    }
6034
6035    pub fn excerpt_boundaries_in_range<R, T>(
6036        &self,
6037        range: R,
6038    ) -> impl Iterator<Item = ExcerptBoundary> + '_
6039    where
6040        R: RangeBounds<T>,
6041        T: ToOffset,
6042    {
6043        let start_offset;
6044        let start = match range.start_bound() {
6045            Bound::Included(start) => {
6046                start_offset = start.to_offset(self);
6047                Bound::Included(start_offset)
6048            }
6049            Bound::Excluded(_) => {
6050                panic!("not supported")
6051            }
6052            Bound::Unbounded => {
6053                start_offset = MultiBufferOffset::ZERO;
6054                Bound::Unbounded
6055            }
6056        };
6057        let end = match range.end_bound() {
6058            Bound::Included(end) => Bound::Included(end.to_offset(self)),
6059            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
6060            Bound::Unbounded => Bound::Unbounded,
6061        };
6062        let bounds = (start, end);
6063        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
6064        cursor.seek(&DimensionPair {
6065            key: start_offset,
6066            value: None,
6067        });
6068
6069        if cursor
6070            .fetch_excerpt_with_range()
6071            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
6072        {
6073            cursor.prev_excerpt();
6074        } else {
6075            cursor.seek_to_start_of_current_excerpt();
6076        }
6077        let mut prev_region = cursor
6078            .fetch_excerpt_with_range()
6079            .map(|(excerpt, _)| excerpt);
6080
6081        cursor.next_excerpt_forwards();
6082
6083        iter::from_fn(move || {
6084            loop {
6085                if self.singleton {
6086                    return None;
6087                }
6088
6089                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
6090                cursor.next_excerpt_forwards();
6091                if !bounds.contains(&next_range.start.key) {
6092                    prev_region = Some(next_excerpt);
6093                    continue;
6094                }
6095
6096                let next_region_start = next_range.start.value.unwrap();
6097                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
6098                    range.start.value.unwrap()
6099                } else {
6100                    self.max_point()
6101                };
6102
6103                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
6104                    id: region.id,
6105                    buffer: region.buffer.clone(),
6106                    buffer_id: region.buffer_id,
6107                    range: region.range.clone(),
6108                    end_row: MultiBufferRow(next_region_start.row),
6109                });
6110
6111                let next = ExcerptInfo {
6112                    id: next_excerpt.id,
6113                    buffer: next_excerpt.buffer.clone(),
6114                    buffer_id: next_excerpt.buffer_id,
6115                    range: next_excerpt.range.clone(),
6116                    end_row: if next_excerpt.has_trailing_newline {
6117                        MultiBufferRow(next_region_end.row - 1)
6118                    } else {
6119                        MultiBufferRow(next_region_end.row)
6120                    },
6121                };
6122
6123                let row = MultiBufferRow(next_region_start.row);
6124
6125                prev_region = Some(next_excerpt);
6126
6127                return Some(ExcerptBoundary { row, prev, next });
6128            }
6129        })
6130    }
6131
6132    pub fn edit_count(&self) -> usize {
6133        self.edit_count
6134    }
6135
6136    pub fn non_text_state_update_count(&self) -> usize {
6137        self.non_text_state_update_count
6138    }
6139
6140    /// Returns the smallest enclosing bracket ranges containing the given range or
6141    /// None if no brackets contain range or the range is not contained in a single
6142    /// excerpt
6143    ///
6144    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6145    #[ztracing::instrument(skip_all)]
6146    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6147        &self,
6148        range: Range<T>,
6149        range_filter: Option<
6150            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6151        >,
6152    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6153        let range = range.start.to_offset(self)..range.end.to_offset(self);
6154        let mut excerpt = self.excerpt_containing(range.clone())?;
6155        let buffer = excerpt.buffer();
6156        let excerpt_buffer_range = excerpt.buffer_range();
6157
6158        // Filter to ranges contained in the excerpt
6159        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6160            excerpt_buffer_range.contains(&BufferOffset(open.start))
6161                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6162                && range_filter.is_none_or(|filter| {
6163                    filter(
6164                        buffer,
6165                        BufferOffset(open.start)..BufferOffset(close.end),
6166                        BufferOffset(close.start)..BufferOffset(close.end),
6167                    )
6168                })
6169        };
6170
6171        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6172            excerpt.map_range_to_buffer(range),
6173            Some(&range_filter),
6174        )?;
6175
6176        Some((
6177            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6178            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6179        ))
6180    }
6181
6182    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6183    /// not contained in a single excerpt
6184    pub fn enclosing_bracket_ranges<T: ToOffset>(
6185        &self,
6186        range: Range<T>,
6187    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6188    {
6189        let range = range.start.to_offset(self)..range.end.to_offset(self);
6190        let mut excerpt = self.excerpt_containing(range.clone())?;
6191
6192        Some(
6193            excerpt
6194                .buffer()
6195                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6196                .filter_map(move |pair| {
6197                    let open_range =
6198                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6199                    let close_range =
6200                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6201                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6202                        Some((
6203                            excerpt.map_range_from_buffer(open_range),
6204                            excerpt.map_range_from_buffer(close_range),
6205                        ))
6206                    } else {
6207                        None
6208                    }
6209                }),
6210        )
6211    }
6212
6213    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6214    /// not contained in a single excerpt
6215    pub fn text_object_ranges<T: ToOffset>(
6216        &self,
6217        range: Range<T>,
6218        options: TreeSitterOptions,
6219    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6220        let range = range.start.to_offset(self)..range.end.to_offset(self);
6221        self.excerpt_containing(range.clone())
6222            .map(|mut excerpt| {
6223                excerpt
6224                    .buffer()
6225                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6226                    .filter_map(move |(range, text_object)| {
6227                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6228                        if excerpt.contains_buffer_range(range.clone()) {
6229                            Some((excerpt.map_range_from_buffer(range), text_object))
6230                        } else {
6231                            None
6232                        }
6233                    })
6234            })
6235            .into_iter()
6236            .flatten()
6237    }
6238
6239    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6240    /// not contained in a single excerpt
6241    pub fn bracket_ranges<T: ToOffset>(
6242        &self,
6243        range: Range<T>,
6244    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6245    {
6246        let range = range.start.to_offset(self)..range.end.to_offset(self);
6247        let mut excerpt = self.excerpt_containing(range.clone())?;
6248        Some(
6249            excerpt
6250                .buffer()
6251                .bracket_ranges(excerpt.map_range_to_buffer(range))
6252                .filter_map(move |pair| {
6253                    let open_range =
6254                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6255                    let close_range =
6256                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6257                    excerpt
6258                        .contains_buffer_range(open_range.start..close_range.end)
6259                        .then(|| BracketMatch {
6260                            open_range: excerpt.map_range_from_buffer(open_range),
6261                            close_range: excerpt.map_range_from_buffer(close_range),
6262                            color_index: pair.color_index,
6263                            newline_only: pair.newline_only,
6264                            syntax_layer_depth: pair.syntax_layer_depth,
6265                        })
6266                })
6267                .map(BracketMatch::bracket_ranges),
6268        )
6269    }
6270
6271    pub fn redacted_ranges<'a, T: ToOffset>(
6272        &'a self,
6273        range: Range<T>,
6274        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6275    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6276        let range = range.start.to_offset(self)..range.end.to_offset(self);
6277        self.lift_buffer_metadata(range, move |buffer, range| {
6278            if redaction_enabled(buffer.file()) {
6279                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6280            } else {
6281                None
6282            }
6283        })
6284        .map(|(range, _, _)| range)
6285    }
6286
6287    pub fn runnable_ranges(
6288        &self,
6289        range: Range<Anchor>,
6290    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6291        let range = range.start.to_offset(self)..range.end.to_offset(self);
6292        self.lift_buffer_metadata(range, move |buffer, range| {
6293            Some(
6294                buffer
6295                    .runnable_ranges(range.clone())
6296                    .filter(move |runnable| {
6297                        runnable.run_range.start >= range.start
6298                            && runnable.run_range.end < range.end
6299                    })
6300                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6301            )
6302        })
6303        .map(|(run_range, runnable, _)| (run_range, runnable))
6304    }
6305
6306    pub fn line_indents(
6307        &self,
6308        start_row: MultiBufferRow,
6309        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6310    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6311        let max_point = self.max_point();
6312        let mut cursor = self.cursor::<Point, Point>();
6313        cursor.seek(&Point::new(start_row.0, 0));
6314        iter::from_fn(move || {
6315            let mut region = cursor.region()?;
6316            while !buffer_filter(&region.excerpt.buffer) {
6317                cursor.next();
6318                region = cursor.region()?;
6319            }
6320            let region = cursor.region()?;
6321            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6322            let buffer_start_row =
6323                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6324
6325            let buffer_end_row = if region.is_main_buffer
6326                && (region.has_trailing_newline || region.range.end == max_point)
6327            {
6328                region.buffer_range.end.row
6329            } else {
6330                region.buffer_range.end.row.saturating_sub(1)
6331            };
6332
6333            let line_indents = region
6334                .buffer
6335                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6336            let region_buffer_row = region.buffer_range.start.row;
6337            let region_row = region.range.start.row;
6338            let region_buffer = &region.excerpt.buffer;
6339            cursor.next();
6340            Some(line_indents.map(move |(buffer_row, indent)| {
6341                let row = region_row + (buffer_row - region_buffer_row);
6342                (MultiBufferRow(row), indent, region_buffer.as_ref())
6343            }))
6344        })
6345        .flatten()
6346    }
6347
6348    pub fn reversed_line_indents(
6349        &self,
6350        end_row: MultiBufferRow,
6351        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6352    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6353        let max_point = self.max_point();
6354        let mut cursor = self.cursor::<Point, Point>();
6355        cursor.seek(&Point::new(end_row.0, 0));
6356        iter::from_fn(move || {
6357            let mut region = cursor.region()?;
6358            while !buffer_filter(&region.excerpt.buffer) {
6359                cursor.prev();
6360                region = cursor.region()?;
6361            }
6362            let region = cursor.region()?;
6363
6364            let buffer_start_row = region.buffer_range.start.row;
6365            let buffer_end_row = if region.is_main_buffer
6366                && (region.has_trailing_newline || region.range.end == max_point)
6367            {
6368                region.buffer_range.end.row + 1
6369            } else {
6370                region.buffer_range.end.row
6371            };
6372
6373            let overshoot = end_row.0 - region.range.start.row;
6374            let buffer_end_row =
6375                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6376
6377            let line_indents = region
6378                .buffer
6379                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6380            let region_buffer_row = region.buffer_range.start.row;
6381            let region_row = region.range.start.row;
6382            let region_buffer = &region.excerpt.buffer;
6383            cursor.prev();
6384            Some(line_indents.map(move |(buffer_row, indent)| {
6385                let row = region_row + (buffer_row - region_buffer_row);
6386                (MultiBufferRow(row), indent, region_buffer.as_ref())
6387            }))
6388        })
6389        .flatten()
6390    }
6391
6392    pub async fn enclosing_indent(
6393        &self,
6394        mut target_row: MultiBufferRow,
6395    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6396        let max_row = MultiBufferRow(self.max_point().row);
6397        if target_row >= max_row {
6398            return None;
6399        }
6400
6401        let mut target_indent = self.line_indent_for_row(target_row);
6402
6403        // If the current row is at the start of an indented block, we want to return this
6404        // block as the enclosing indent.
6405        if !target_indent.is_line_empty() && target_row < max_row {
6406            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6407            if !next_line_indent.is_line_empty()
6408                && target_indent.raw_len() < next_line_indent.raw_len()
6409            {
6410                target_indent = next_line_indent;
6411                target_row.0 += 1;
6412            }
6413        }
6414
6415        const SEARCH_ROW_LIMIT: u32 = 25000;
6416        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6417        const YIELD_INTERVAL: u32 = 100;
6418
6419        let mut accessed_row_counter = 0;
6420
6421        // If there is a blank line at the current row, search for the next non indented lines
6422        if target_indent.is_line_empty() {
6423            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6424            let end =
6425                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6426
6427            let mut non_empty_line_above = None;
6428            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6429                if row < start {
6430                    break;
6431                }
6432                accessed_row_counter += 1;
6433                if accessed_row_counter == YIELD_INTERVAL {
6434                    accessed_row_counter = 0;
6435                    yield_now().await;
6436                }
6437                if !indent.is_line_empty() {
6438                    non_empty_line_above = Some((row, indent));
6439                    break;
6440                }
6441            }
6442
6443            let mut non_empty_line_below = None;
6444            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6445                if row > end {
6446                    break;
6447                }
6448                accessed_row_counter += 1;
6449                if accessed_row_counter == YIELD_INTERVAL {
6450                    accessed_row_counter = 0;
6451                    yield_now().await;
6452                }
6453                if !indent.is_line_empty() {
6454                    non_empty_line_below = Some((row, indent));
6455                    break;
6456                }
6457            }
6458
6459            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6460                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6461                    if above_indent.raw_len() >= below_indent.raw_len() {
6462                        (above_row, above_indent)
6463                    } else {
6464                        (below_row, below_indent)
6465                    }
6466                }
6467                (Some(above), None) => above,
6468                (None, Some(below)) => below,
6469                _ => return None,
6470            };
6471
6472            target_indent = indent;
6473            target_row = row;
6474        }
6475
6476        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6477        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6478
6479        let mut start_indent = None;
6480        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6481            if row < start {
6482                break;
6483            }
6484            accessed_row_counter += 1;
6485            if accessed_row_counter == YIELD_INTERVAL {
6486                accessed_row_counter = 0;
6487                yield_now().await;
6488            }
6489            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6490                start_indent = Some((row, indent));
6491                break;
6492            }
6493        }
6494        let (start_row, start_indent_size) = start_indent?;
6495
6496        let mut end_indent = (end, None);
6497        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6498            if row > end {
6499                break;
6500            }
6501            accessed_row_counter += 1;
6502            if accessed_row_counter == YIELD_INTERVAL {
6503                accessed_row_counter = 0;
6504                yield_now().await;
6505            }
6506            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6507                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6508                break;
6509            }
6510        }
6511        let (end_row, end_indent_size) = end_indent;
6512
6513        let indent = if let Some(end_indent_size) = end_indent_size {
6514            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6515                start_indent_size
6516            } else {
6517                end_indent_size
6518            }
6519        } else {
6520            start_indent_size
6521        };
6522
6523        Some((start_row..end_row, indent))
6524    }
6525
6526    pub fn indent_guides_in_range<T: ToPoint>(
6527        &self,
6528        range: Range<T>,
6529        ignore_disabled_for_language: bool,
6530        cx: &App,
6531    ) -> impl Iterator<Item = IndentGuide> {
6532        let range = range.start.to_point(self)..range.end.to_point(self);
6533        let start_row = MultiBufferRow(range.start.row);
6534        let end_row = MultiBufferRow(range.end.row);
6535
6536        let mut row_indents = self.line_indents(start_row, |buffer| {
6537            let settings =
6538                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6539            settings.indent_guides.enabled || ignore_disabled_for_language
6540        });
6541
6542        let mut result = Vec::new();
6543        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6544
6545        let mut prev_settings = None;
6546        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6547            if first_row > end_row {
6548                break;
6549            }
6550            let current_depth = indent_stack.len() as u32;
6551
6552            // Avoid retrieving the language settings repeatedly for every buffer row.
6553            if let Some((prev_buffer_id, _)) = &prev_settings
6554                && prev_buffer_id != &buffer.remote_id()
6555            {
6556                prev_settings.take();
6557            }
6558            let settings = &prev_settings
6559                .get_or_insert_with(|| {
6560                    (
6561                        buffer.remote_id(),
6562                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6563                    )
6564                })
6565                .1;
6566            let tab_size = settings.tab_size.get();
6567
6568            // When encountering empty, continue until found useful line indent
6569            // then add to the indent stack with the depth found
6570            let mut found_indent = false;
6571            let mut last_row = first_row;
6572            if line_indent.is_line_blank() {
6573                while !found_indent {
6574                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6575                        break;
6576                    };
6577                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6578                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6579                        break;
6580                    }
6581
6582                    if new_line_indent.is_line_blank() {
6583                        continue;
6584                    }
6585                    last_row = target_row.min(end_row);
6586                    line_indent = new_line_indent;
6587                    found_indent = true;
6588                    break;
6589                }
6590            } else {
6591                found_indent = true
6592            }
6593
6594            let depth = if found_indent {
6595                line_indent.len(tab_size) / tab_size
6596            } else {
6597                0
6598            };
6599
6600            match depth.cmp(&current_depth) {
6601                cmp::Ordering::Less => {
6602                    for _ in 0..(current_depth - depth) {
6603                        let mut indent = indent_stack.pop().unwrap();
6604                        if last_row != first_row {
6605                            // In this case, we landed on an empty row, had to seek forward,
6606                            // and discovered that the indent we where on is ending.
6607                            // This means that the last display row must
6608                            // be on line that ends this indent range, so we
6609                            // should display the range up to the first non-empty line
6610                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6611                        }
6612
6613                        result.push(indent)
6614                    }
6615                }
6616                cmp::Ordering::Greater => {
6617                    for next_depth in current_depth..depth {
6618                        indent_stack.push(IndentGuide {
6619                            buffer_id: buffer.remote_id(),
6620                            start_row: first_row,
6621                            end_row: last_row,
6622                            depth: next_depth,
6623                            tab_size,
6624                            settings: settings.indent_guides.clone(),
6625                        });
6626                    }
6627                }
6628                _ => {}
6629            }
6630
6631            for indent in indent_stack.iter_mut() {
6632                indent.end_row = last_row;
6633            }
6634        }
6635
6636        result.extend(indent_stack);
6637        result.into_iter()
6638    }
6639
6640    pub fn trailing_excerpt_update_count(&self) -> usize {
6641        self.trailing_excerpt_update_count
6642    }
6643
6644    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6645        self.point_to_buffer_offset(point)
6646            .and_then(|(buffer, _)| buffer.file())
6647    }
6648
6649    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6650        self.point_to_buffer_offset(offset)
6651            .and_then(|(buffer, offset)| buffer.language_at(offset))
6652    }
6653
6654    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6655        self.excerpts
6656            .first()
6657            .map(|excerpt| &excerpt.buffer)
6658            .map(|buffer| {
6659                language_settings(
6660                    buffer.language().map(|language| language.name()),
6661                    buffer.file(),
6662                    cx,
6663                )
6664            })
6665            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6666    }
6667
6668    pub fn language_settings_at<'a, T: ToOffset>(
6669        &'a self,
6670        point: T,
6671        cx: &'a App,
6672    ) -> Cow<'a, LanguageSettings> {
6673        let mut language = None;
6674        let mut file = None;
6675        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6676            language = buffer.language_at(offset);
6677            file = buffer.file();
6678        }
6679        language_settings(language.map(|l| l.name()), file, cx)
6680    }
6681
6682    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6683        self.point_to_buffer_offset(point)
6684            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6685    }
6686
6687    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6688        self.point_to_buffer_offset(point)
6689            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6690            .unwrap_or_default()
6691    }
6692
6693    pub fn language_indent_size_at<T: ToOffset>(
6694        &self,
6695        position: T,
6696        cx: &App,
6697    ) -> Option<IndentSize> {
6698        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6699        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6700    }
6701
6702    pub fn is_dirty(&self) -> bool {
6703        self.is_dirty
6704    }
6705
6706    pub fn has_deleted_file(&self) -> bool {
6707        self.has_deleted_file
6708    }
6709
6710    pub fn has_conflict(&self) -> bool {
6711        self.has_conflict
6712    }
6713
6714    pub fn has_diagnostics(&self) -> bool {
6715        self.excerpts
6716            .iter()
6717            .any(|excerpt| excerpt.buffer.has_diagnostics())
6718    }
6719
6720    pub fn diagnostic_group(
6721        &self,
6722        buffer_id: BufferId,
6723        group_id: usize,
6724    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6725        self.lift_buffer_metadata::<Point, _, _>(
6726            Point::zero()..self.max_point(),
6727            move |buffer, range| {
6728                if buffer.remote_id() != buffer_id {
6729                    return None;
6730                };
6731                Some(
6732                    buffer
6733                        .diagnostics_in_range(range, false)
6734                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6735                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6736                )
6737            },
6738        )
6739        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6740    }
6741
6742    pub fn diagnostics_in_range<'a, MBD>(
6743        &'a self,
6744        range: Range<MBD>,
6745    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6746    where
6747        MBD::TextDimension: 'a
6748            + text::ToOffset
6749            + text::FromAnchor
6750            + Sub<Output = MBD::TextDimension>
6751            + fmt::Debug
6752            + ops::Add<Output = MBD::TextDimension>
6753            + ops::AddAssign
6754            + Ord,
6755        MBD: MultiBufferDimension
6756            + Ord
6757            + Sub<Output = MBD::TextDimension>
6758            + ops::Add<MBD::TextDimension, Output = MBD>
6759            + ops::AddAssign<MBD::TextDimension>
6760            + 'a,
6761    {
6762        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6763            Some(
6764                buffer
6765                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6766                    .map(|entry| (entry.range, entry.diagnostic)),
6767            )
6768        })
6769        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6770    }
6771
6772    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6773        &'a self,
6774        range: Range<MBD>,
6775    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6776    where
6777        MBD: MultiBufferDimension
6778            + Ord
6779            + Sub<Output = MBD::TextDimension>
6780            + ops::Add<MBD::TextDimension, Output = MBD>
6781            + ops::AddAssign<MBD::TextDimension>,
6782        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6783            + ops::Add<Output = MBD::TextDimension>
6784            + text::ToOffset
6785            + text::FromAnchor
6786            + AddAssign<MBD::TextDimension>
6787            + Ord,
6788    {
6789        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6790            Some(
6791                buffer
6792                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6793                    .map(|entry| (entry.range, entry.diagnostic)),
6794            )
6795        })
6796        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6797    }
6798
6799    pub fn syntax_ancestor<T: ToOffset>(
6800        &self,
6801        range: Range<T>,
6802    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6803        let range = range.start.to_offset(self)..range.end.to_offset(self);
6804        let mut excerpt = self.excerpt_containing(range.clone())?;
6805        let node = excerpt
6806            .buffer()
6807            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6808        let node_range = node.byte_range();
6809        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6810        if !excerpt.contains_buffer_range(node_range.clone()) {
6811            return None;
6812        };
6813        Some((node, excerpt.map_range_from_buffer(node_range)))
6814    }
6815
6816    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6817        let (excerpt_id, _, buffer) = self.as_singleton()?;
6818        let outline = buffer.outline(theme);
6819        Some(Outline::new(
6820            outline
6821                .items
6822                .into_iter()
6823                .flat_map(|item| {
6824                    Some(OutlineItem {
6825                        depth: item.depth,
6826                        range: self.anchor_range_in_excerpt(excerpt_id, item.range)?,
6827                        source_range_for_text: self
6828                            .anchor_range_in_excerpt(excerpt_id, item.source_range_for_text)?,
6829                        text: item.text,
6830                        highlight_ranges: item.highlight_ranges,
6831                        name_ranges: item.name_ranges,
6832                        body_range: item.body_range.and_then(|body_range| {
6833                            self.anchor_range_in_excerpt(excerpt_id, body_range)
6834                        }),
6835                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6836                            self.anchor_range_in_excerpt(excerpt_id, annotation_range)
6837                        }),
6838                    })
6839                })
6840                .collect(),
6841        ))
6842    }
6843
6844    pub fn symbols_containing<T: ToOffset>(
6845        &self,
6846        offset: T,
6847        theme: Option<&SyntaxTheme>,
6848    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6849        let anchor = self.anchor_before(offset);
6850        let excerpt @ &Excerpt {
6851            id: excerpt_id,
6852            buffer_id,
6853            ref buffer,
6854            ..
6855        } = self.excerpt(anchor.excerpt_id)?;
6856        if cfg!(debug_assertions) {
6857            match anchor.text_anchor.buffer_id {
6858                // we clearly are hitting this according to sentry, but in what situations can this occur?
6859                Some(anchor_buffer_id) => {
6860                    assert_eq!(
6861                        anchor_buffer_id, buffer_id,
6862                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6863                    )
6864                }
6865                None => assert!(anchor.is_max()),
6866            }
6867        };
6868        Some((
6869            buffer_id,
6870            buffer
6871                .symbols_containing(anchor.text_anchor, theme)
6872                .into_iter()
6873                .flat_map(|item| {
6874                    Some(OutlineItem {
6875                        depth: item.depth,
6876                        source_range_for_text: Anchor::range_in_buffer(
6877                            excerpt_id,
6878                            item.source_range_for_text,
6879                        ),
6880                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6881                        text: item.text,
6882                        highlight_ranges: item.highlight_ranges,
6883                        name_ranges: item.name_ranges,
6884                        body_range: item
6885                            .body_range
6886                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6887                        annotation_range: item
6888                            .annotation_range
6889                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6890                    })
6891                })
6892                .collect(),
6893        ))
6894    }
6895
6896    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6897        if id == ExcerptId::min() {
6898            Locator::min_ref()
6899        } else if id == ExcerptId::max() {
6900            Locator::max_ref()
6901        } else {
6902            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6903            if let Some(entry) = item
6904                && entry.id == id
6905            {
6906                return &entry.locator;
6907            }
6908            panic!("invalid excerpt id {id:?}")
6909        }
6910    }
6911
6912    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6913    fn excerpt_locators_for_ids(
6914        &self,
6915        ids: impl IntoIterator<Item = ExcerptId>,
6916    ) -> SmallVec<[Locator; 1]> {
6917        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6918        sorted_ids.sort_unstable();
6919        sorted_ids.dedup();
6920        let mut locators = SmallVec::new();
6921
6922        while sorted_ids.last() == Some(&ExcerptId::max()) {
6923            sorted_ids.pop();
6924            locators.push(Locator::max());
6925        }
6926
6927        let mut sorted_ids = sorted_ids.into_iter().peekable();
6928        locators.extend(
6929            sorted_ids
6930                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6931                .map(|_| Locator::min()),
6932        );
6933
6934        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6935        for id in sorted_ids {
6936            if cursor.seek_forward(&id, Bias::Left) {
6937                locators.push(cursor.item().unwrap().locator.clone());
6938            } else {
6939                panic!("invalid excerpt id {:?}", id);
6940            }
6941        }
6942
6943        locators.sort_unstable();
6944        locators
6945    }
6946
6947    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6948        Some(self.excerpt(excerpt_id)?.buffer_id)
6949    }
6950
6951    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6952        Some(&self.excerpt(excerpt_id)?.buffer)
6953    }
6954
6955    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6956        let mut cursor = self
6957            .excerpts
6958            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6959        let locator = self.excerpt_locator_for_id(excerpt_id);
6960        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6961        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6962            sought_exact = true;
6963            cursor.prev();
6964        } else if excerpt_id == ExcerptId::min() {
6965            sought_exact = true;
6966        }
6967        if sought_exact {
6968            let start = cursor.start().1;
6969            let end = cursor.end().1;
6970            let mut diff_transforms = self
6971                .diff_transforms
6972                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6973            diff_transforms.seek(&start, Bias::Left);
6974            let overshoot = start - diff_transforms.start().0;
6975            let start = diff_transforms.start().1 + overshoot;
6976            diff_transforms.seek(&end, Bias::Right);
6977            let overshoot = end - diff_transforms.start().0;
6978            let end = diff_transforms.start().1 + overshoot;
6979            Some(start.0..end.0)
6980        } else {
6981            None
6982        }
6983    }
6984
6985    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6986    /// to have the latest excerpt id for the one passed in and will also remap
6987    /// `ExcerptId::max()` to the corresponding excertp ID.
6988    ///
6989    /// Callers of this function should generally use the resulting excerpt's `id` field
6990    /// afterwards.
6991    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6992        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6993        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6994        let locator = self.excerpt_locator_for_id(excerpt_id);
6995        cursor.seek(&Some(locator), Bias::Left);
6996        if let Some(excerpt) = cursor.item()
6997            && excerpt.id == excerpt_id
6998        {
6999            return Some(excerpt);
7000        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
7001            cursor.prev();
7002            return cursor.item();
7003        }
7004        None
7005    }
7006
7007    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
7008    pub fn excerpt_containing<T: ToOffset>(
7009        &self,
7010        range: Range<T>,
7011    ) -> Option<MultiBufferExcerpt<'_>> {
7012        let range = range.start.to_offset(self)..range.end.to_offset(self);
7013        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
7014        cursor.seek(&range.start);
7015
7016        let start_excerpt = cursor.excerpt()?;
7017        if range.end != range.start {
7018            cursor.seek_forward(&range.end);
7019            if cursor.excerpt()?.id != start_excerpt.id {
7020                return None;
7021            }
7022        }
7023
7024        cursor.seek_to_start_of_current_excerpt();
7025        let region = cursor.region()?;
7026        let offset = region.range.start;
7027        let buffer_offset = start_excerpt.buffer_start_offset();
7028        let excerpt_offset = *cursor.excerpts.start();
7029        Some(MultiBufferExcerpt {
7030            diff_transforms: cursor.diff_transforms,
7031            excerpt: start_excerpt,
7032            offset,
7033            buffer_offset,
7034            excerpt_offset,
7035        })
7036    }
7037
7038    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
7039        if let Some(id) = anchor.text_anchor.buffer_id {
7040            return Some(id);
7041        }
7042        let excerpt = self.excerpt_containing(anchor..anchor)?;
7043        Some(excerpt.buffer_id())
7044    }
7045
7046    pub fn selections_in_range<'a>(
7047        &'a self,
7048        range: &'a Range<Anchor>,
7049        include_local: bool,
7050    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
7051        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
7052        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
7053        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
7054        cursor.seek(start_locator, Bias::Left);
7055        cursor
7056            .take_while(move |excerpt| excerpt.locator <= *end_locator)
7057            .flat_map(move |excerpt| {
7058                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
7059                if excerpt.id == range.start.excerpt_id {
7060                    query_range.start = range.start.text_anchor;
7061                }
7062                if excerpt.id == range.end.excerpt_id {
7063                    query_range.end = range.end.text_anchor;
7064                }
7065
7066                excerpt
7067                    .buffer
7068                    .selections_in_range(query_range, include_local)
7069                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
7070                        selections.map(move |selection| {
7071                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
7072                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
7073                            if range.start.cmp(&start, self).is_gt() {
7074                                start = range.start;
7075                            }
7076                            if range.end.cmp(&end, self).is_lt() {
7077                                end = range.end;
7078                            }
7079
7080                            (
7081                                replica_id,
7082                                line_mode,
7083                                cursor_shape,
7084                                Selection {
7085                                    id: selection.id,
7086                                    start,
7087                                    end,
7088                                    reversed: selection.reversed,
7089                                    goal: selection.goal,
7090                                },
7091                            )
7092                        })
7093                    })
7094            })
7095    }
7096
7097    pub fn show_headers(&self) -> bool {
7098        self.show_headers
7099    }
7100
7101    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
7102        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
7103    }
7104
7105    pub fn all_diff_hunks_expanded(&self) -> bool {
7106        self.all_diff_hunks_expanded
7107    }
7108
7109    /// Visually annotates a position or range with the `Debug` representation of a value. The
7110    /// callsite of this function is used as a key - previous annotations will be removed.
7111    #[cfg(debug_assertions)]
7112    #[track_caller]
7113    pub fn debug<V, R>(&self, ranges: &R, value: V)
7114    where
7115        R: debug::ToMultiBufferDebugRanges,
7116        V: std::fmt::Debug,
7117    {
7118        self.debug_with_key(std::panic::Location::caller(), ranges, value);
7119    }
7120
7121    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
7122    /// debug annotations with the same key will be removed. The key is also used to determine the
7123    /// annotation's color.
7124    #[cfg(debug_assertions)]
7125    #[track_caller]
7126    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
7127    where
7128        K: std::hash::Hash + 'static,
7129        R: debug::ToMultiBufferDebugRanges,
7130        V: std::fmt::Debug,
7131    {
7132        let text_ranges = ranges
7133            .to_multi_buffer_debug_ranges(self)
7134            .into_iter()
7135            .flat_map(|range| {
7136                self.range_to_buffer_ranges(range.start..=range.end)
7137                    .into_iter()
7138                    .map(|(buffer, range, _excerpt_id)| {
7139                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7140                    })
7141            })
7142            .collect();
7143        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7144            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7145        });
7146    }
7147
7148    fn excerpt_edits_for_diff_change(
7149        &self,
7150        buffer_state: &BufferState,
7151        diff_change_range: Range<usize>,
7152    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7153        let mut excerpt_edits = Vec::new();
7154        for locator in &buffer_state.excerpts {
7155            let mut cursor = self
7156                .excerpts
7157                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7158            cursor.seek_forward(&Some(locator), Bias::Left);
7159            if let Some(excerpt) = cursor.item()
7160                && excerpt.locator == *locator
7161            {
7162                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7163                if diff_change_range.end < excerpt_buffer_range.start
7164                    || diff_change_range.start > excerpt_buffer_range.end
7165                {
7166                    continue;
7167                }
7168                let excerpt_start = cursor.start().1;
7169                let excerpt_len = excerpt.text_summary.len;
7170                let diff_change_start_in_excerpt = diff_change_range
7171                    .start
7172                    .saturating_sub(excerpt_buffer_range.start);
7173                let diff_change_end_in_excerpt = diff_change_range
7174                    .end
7175                    .saturating_sub(excerpt_buffer_range.start);
7176                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7177                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7178                excerpt_edits.push(Edit {
7179                    old: edit_start..edit_end,
7180                    new: edit_start..edit_end,
7181                });
7182            }
7183        }
7184        excerpt_edits
7185    }
7186}
7187
7188#[cfg(any(test, feature = "test-support"))]
7189impl MultiBufferSnapshot {
7190    pub fn random_byte_range(
7191        &self,
7192        start_offset: MultiBufferOffset,
7193        rng: &mut impl rand::Rng,
7194    ) -> Range<MultiBufferOffset> {
7195        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7196        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7197        start..end
7198    }
7199
7200    #[cfg(any(test, feature = "test-support"))]
7201    fn check_invariants(&self) {
7202        let excerpts = self.excerpts.items(());
7203        let excerpt_ids = self.excerpt_ids.items(());
7204
7205        for (ix, excerpt) in excerpts.iter().enumerate() {
7206            if ix == 0 {
7207                if excerpt.locator <= Locator::min() {
7208                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7209                }
7210            } else if excerpt.locator <= excerpts[ix - 1].locator {
7211                panic!("excerpts are out-of-order: {:?}", excerpts);
7212            }
7213        }
7214
7215        for (ix, entry) in excerpt_ids.iter().enumerate() {
7216            if ix == 0 {
7217                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7218                    panic!("invalid first excerpt id {:?}", entry.id);
7219                }
7220            } else if entry.id <= excerpt_ids[ix - 1].id {
7221                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7222            }
7223        }
7224
7225        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7226            panic!(
7227                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7228                self.excerpts.summary().text,
7229                self.diff_transforms.summary().input,
7230                self.diff_transforms.items(()),
7231            );
7232        }
7233
7234        let mut prev_transform: Option<&DiffTransform> = None;
7235        for item in self.diff_transforms.iter() {
7236            if let DiffTransform::BufferContent {
7237                summary,
7238                inserted_hunk_info,
7239            } = item
7240            {
7241                if let Some(DiffTransform::BufferContent {
7242                    inserted_hunk_info: prev_inserted_hunk_info,
7243                    ..
7244                }) = prev_transform
7245                    && *inserted_hunk_info == *prev_inserted_hunk_info
7246                {
7247                    panic!(
7248                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7249                        self.diff_transforms.items(())
7250                    );
7251                }
7252                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7253                    panic!("empty buffer content transform");
7254                }
7255            }
7256            prev_transform = Some(item);
7257        }
7258    }
7259}
7260
7261impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7262where
7263    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7264    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7265{
7266    #[instrument(skip_all)]
7267    fn seek(&mut self, position: &MBD) {
7268        let position = OutputDimension(*position);
7269        self.cached_region.take();
7270        self.diff_transforms.seek(&position, Bias::Right);
7271        if self.diff_transforms.item().is_none()
7272            && self.diff_transforms.start().output_dimension == position
7273        {
7274            self.diff_transforms.prev();
7275        }
7276
7277        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7278        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7279            let overshoot = position - self.diff_transforms.start().output_dimension;
7280            excerpt_position += overshoot;
7281        }
7282
7283        self.excerpts.seek(&excerpt_position, Bias::Right);
7284        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7285            self.excerpts.prev();
7286        }
7287    }
7288
7289    fn seek_forward(&mut self, position: &MBD) {
7290        let position = OutputDimension(*position);
7291        self.cached_region.take();
7292        self.diff_transforms.seek_forward(&position, Bias::Right);
7293        if self.diff_transforms.item().is_none()
7294            && self.diff_transforms.start().output_dimension == position
7295        {
7296            self.diff_transforms.prev();
7297        }
7298
7299        let overshoot = position - self.diff_transforms.start().output_dimension;
7300        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7301        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7302            excerpt_position += overshoot;
7303        }
7304
7305        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7306        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7307            self.excerpts.prev();
7308        }
7309    }
7310
7311    fn next_excerpt(&mut self) {
7312        self.excerpts.next();
7313        self.seek_to_start_of_current_excerpt();
7314    }
7315
7316    fn prev_excerpt(&mut self) {
7317        self.excerpts.prev();
7318        self.seek_to_start_of_current_excerpt();
7319    }
7320
7321    fn seek_to_start_of_current_excerpt(&mut self) {
7322        self.cached_region.take();
7323
7324        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7325            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7326            && self.diff_transforms.next_item().is_some()
7327        {
7328            self.diff_transforms.next();
7329        }
7330    }
7331
7332    fn next_excerpt_forwards(&mut self) {
7333        self.excerpts.next();
7334        self.seek_to_start_of_current_excerpt_forward();
7335    }
7336
7337    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7338        self.cached_region.take();
7339
7340        if self
7341            .diff_transforms
7342            .seek_forward(self.excerpts.start(), Bias::Left)
7343            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7344            && self.diff_transforms.next_item().is_some()
7345        {
7346            self.diff_transforms.next();
7347        }
7348    }
7349
7350    fn next(&mut self) {
7351        self.cached_region.take();
7352        match self
7353            .diff_transforms
7354            .end()
7355            .excerpt_dimension
7356            .cmp(&self.excerpts.end())
7357        {
7358            cmp::Ordering::Less => self.diff_transforms.next(),
7359            cmp::Ordering::Greater => self.excerpts.next(),
7360            cmp::Ordering::Equal => {
7361                self.diff_transforms.next();
7362                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7363                    || self.diff_transforms.item().is_none()
7364                {
7365                    self.excerpts.next();
7366                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7367                    self.diff_transforms.item()
7368                    && self
7369                        .excerpts
7370                        .item()
7371                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7372                {
7373                    self.excerpts.next();
7374                }
7375            }
7376        }
7377    }
7378
7379    fn prev(&mut self) {
7380        self.cached_region.take();
7381        match self
7382            .diff_transforms
7383            .start()
7384            .excerpt_dimension
7385            .cmp(self.excerpts.start())
7386        {
7387            cmp::Ordering::Less => self.excerpts.prev(),
7388            cmp::Ordering::Greater => self.diff_transforms.prev(),
7389            cmp::Ordering::Equal => {
7390                self.diff_transforms.prev();
7391                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7392                    || self.diff_transforms.item().is_none()
7393                {
7394                    self.excerpts.prev();
7395                }
7396            }
7397        }
7398    }
7399
7400    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7401        self.cached_region
7402            .get_or_init(|| self.build_region())
7403            .as_ref()
7404    }
7405
7406    fn is_at_start_of_excerpt(&mut self) -> bool {
7407        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7408            return false;
7409        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7410            return true;
7411        }
7412
7413        self.diff_transforms.prev();
7414        let prev_transform = self.diff_transforms.item();
7415        self.diff_transforms.next();
7416
7417        prev_transform.is_none_or(|next_transform| {
7418            matches!(next_transform, DiffTransform::BufferContent { .. })
7419        })
7420    }
7421
7422    fn is_at_end_of_excerpt(&self) -> bool {
7423        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7424            return false;
7425        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7426            || self.diff_transforms.item().is_none()
7427        {
7428            return true;
7429        }
7430
7431        let next_transform = self.diff_transforms.next_item();
7432        next_transform.is_none_or(|next_transform| match next_transform {
7433            DiffTransform::BufferContent { .. } => true,
7434            DiffTransform::DeletedHunk { hunk_info, .. } => self
7435                .excerpts
7436                .item()
7437                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7438        })
7439    }
7440
7441    fn main_buffer_position(&self) -> Option<BD> {
7442        let excerpt = self.excerpts.item()?;
7443        let buffer = &excerpt.buffer;
7444        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7445        let mut buffer_start = buffer_context_start;
7446        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7447        buffer_start += overshoot;
7448        Some(buffer_start)
7449    }
7450
7451    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7452        let excerpt = self.excerpts.item()?;
7453        match self.diff_transforms.item()? {
7454            DiffTransform::DeletedHunk {
7455                buffer_id,
7456                base_text_byte_range,
7457                has_trailing_newline,
7458                hunk_info,
7459                ..
7460            } => {
7461                let diff = self.diffs.get(buffer_id)?;
7462                let buffer = diff.base_text();
7463                let mut rope_cursor = buffer.as_rope().cursor(0);
7464                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7465                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7466                let mut buffer_end = buffer_start;
7467                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7468                let start = self.diff_transforms.start().output_dimension.0;
7469                let end = self.diff_transforms.end().output_dimension.0;
7470                Some(MultiBufferRegion {
7471                    buffer,
7472                    excerpt,
7473                    has_trailing_newline: *has_trailing_newline,
7474                    is_main_buffer: false,
7475                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7476                        hunk_info.hunk_secondary_status,
7477                    )),
7478                    buffer_range: buffer_start..buffer_end,
7479                    range: start..end,
7480                })
7481            }
7482            DiffTransform::BufferContent {
7483                inserted_hunk_info, ..
7484            } => {
7485                let buffer = &excerpt.buffer;
7486                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7487
7488                let mut start = self.diff_transforms.start().output_dimension.0;
7489                let mut buffer_start = buffer_context_start;
7490                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7491                    let overshoot =
7492                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7493                    start += overshoot;
7494                } else {
7495                    let overshoot =
7496                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7497                    buffer_start += overshoot;
7498                }
7499
7500                let mut end;
7501                let mut buffer_end;
7502                let has_trailing_newline;
7503                let transform_end = self.diff_transforms.end();
7504                if transform_end.excerpt_dimension < self.excerpts.end() {
7505                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7506                    end = transform_end.output_dimension.0;
7507                    buffer_end = buffer_context_start;
7508                    buffer_end += overshoot;
7509                    has_trailing_newline = false;
7510                } else {
7511                    let overshoot =
7512                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7513                    end = self.diff_transforms.start().output_dimension.0;
7514                    end += overshoot;
7515                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7516                    has_trailing_newline = excerpt.has_trailing_newline;
7517                };
7518
7519                let diff_hunk_status = inserted_hunk_info.map(|info| {
7520                    if info.is_logically_deleted {
7521                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7522                    } else {
7523                        DiffHunkStatus::added(info.hunk_secondary_status)
7524                    }
7525                });
7526
7527                Some(MultiBufferRegion {
7528                    buffer,
7529                    excerpt,
7530                    has_trailing_newline,
7531                    is_main_buffer: true,
7532                    diff_hunk_status,
7533                    buffer_range: buffer_start..buffer_end,
7534                    range: start..end,
7535                })
7536            }
7537        }
7538    }
7539
7540    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7541        let excerpt = self.excerpts.item()?;
7542        match self.diff_transforms.item()? {
7543            &DiffTransform::DeletedHunk { .. } => {
7544                let start = self.diff_transforms.start().output_dimension.0;
7545                let end = self.diff_transforms.end().output_dimension.0;
7546                Some((excerpt, start..end))
7547            }
7548            DiffTransform::BufferContent { .. } => {
7549                let mut start = self.diff_transforms.start().output_dimension.0;
7550                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7551                    let overshoot =
7552                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7553                    start += overshoot;
7554                }
7555
7556                let mut end;
7557                let transform_end = self.diff_transforms.end();
7558                if transform_end.excerpt_dimension < self.excerpts.end() {
7559                    end = transform_end.output_dimension.0;
7560                } else {
7561                    let overshoot =
7562                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7563                    end = self.diff_transforms.start().output_dimension.0;
7564                    end += overshoot;
7565                };
7566
7567                Some((excerpt, start..end))
7568            }
7569        }
7570    }
7571
7572    fn excerpt(&self) -> Option<&'a Excerpt> {
7573        self.excerpts.item()
7574    }
7575}
7576
7577impl Excerpt {
7578    fn new(
7579        id: ExcerptId,
7580        locator: Locator,
7581        buffer_id: BufferId,
7582        buffer: Arc<BufferSnapshot>,
7583        range: ExcerptRange<text::Anchor>,
7584        has_trailing_newline: bool,
7585    ) -> Self {
7586        Excerpt {
7587            id,
7588            locator,
7589            max_buffer_row: range.context.end.to_point(&buffer).row,
7590            text_summary: buffer
7591                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7592            buffer_id,
7593            buffer,
7594            range,
7595            has_trailing_newline,
7596        }
7597    }
7598
7599    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7600        let content_start = self.range.context.start.to_offset(&self.buffer);
7601        let chunks_start = content_start + range.start;
7602        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7603
7604        let has_footer = self.has_trailing_newline
7605            && range.start <= self.text_summary.len
7606            && range.end > self.text_summary.len;
7607
7608        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7609
7610        ExcerptChunks {
7611            excerpt_id: self.id,
7612            content_chunks,
7613            has_footer,
7614        }
7615    }
7616
7617    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7618        let content_start = self.range.context.start.to_offset(&self.buffer);
7619        let chunks_start = content_start + range.start;
7620        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7621        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7622        excerpt_chunks.has_footer = self.has_trailing_newline
7623            && range.start <= self.text_summary.len
7624            && range.end > self.text_summary.len;
7625    }
7626
7627    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7628        if text_anchor
7629            .cmp(&self.range.context.start, &self.buffer)
7630            .is_lt()
7631        {
7632            self.range.context.start
7633        } else if text_anchor
7634            .cmp(&self.range.context.end, &self.buffer)
7635            .is_gt()
7636        {
7637            self.range.context.end
7638        } else {
7639            text_anchor
7640        }
7641    }
7642
7643    fn contains(&self, anchor: &Anchor) -> bool {
7644        (anchor.text_anchor.buffer_id == None
7645            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7646            && self
7647                .range
7648                .context
7649                .start
7650                .cmp(&anchor.text_anchor, &self.buffer)
7651                .is_le()
7652            && self
7653                .range
7654                .context
7655                .end
7656                .cmp(&anchor.text_anchor, &self.buffer)
7657                .is_ge()
7658    }
7659
7660    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7661    fn buffer_start_offset(&self) -> BufferOffset {
7662        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7663    }
7664
7665    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7666    fn buffer_end_offset(&self) -> BufferOffset {
7667        self.buffer_start_offset() + self.text_summary.len
7668    }
7669}
7670
7671impl<'a> MultiBufferExcerpt<'a> {
7672    pub fn id(&self) -> ExcerptId {
7673        self.excerpt.id
7674    }
7675
7676    pub fn buffer_id(&self) -> BufferId {
7677        self.excerpt.buffer_id
7678    }
7679
7680    pub fn start_anchor(&self) -> Anchor {
7681        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7682    }
7683
7684    pub fn end_anchor(&self) -> Anchor {
7685        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7686    }
7687
7688    pub fn buffer(&self) -> &'a BufferSnapshot {
7689        &self.excerpt.buffer
7690    }
7691
7692    pub fn buffer_range(&self) -> Range<BufferOffset> {
7693        self.buffer_offset
7694            ..BufferOffset(
7695                self.excerpt
7696                    .range
7697                    .context
7698                    .end
7699                    .to_offset(&self.excerpt.buffer.text),
7700            )
7701    }
7702
7703    pub fn start_offset(&self) -> MultiBufferOffset {
7704        self.offset
7705    }
7706
7707    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7708    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7709        self.map_range_to_buffer(offset..offset).start
7710    }
7711
7712    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7713    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7714        self.diff_transforms
7715            .seek(&OutputDimension(range.start), Bias::Right);
7716        let start = self.map_offset_to_buffer_internal(range.start);
7717        let end = if range.end > range.start {
7718            self.diff_transforms
7719                .seek_forward(&OutputDimension(range.end), Bias::Right);
7720            self.map_offset_to_buffer_internal(range.end)
7721        } else {
7722            start
7723        };
7724        start..end
7725    }
7726
7727    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7728        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7729        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7730            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7731        };
7732        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7733        self.buffer_offset + offset_in_excerpt
7734    }
7735
7736    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7737    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7738        self.map_range_from_buffer(buffer_offset..buffer_offset)
7739            .start
7740    }
7741
7742    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7743    pub fn map_range_from_buffer(
7744        &mut self,
7745        buffer_range: Range<BufferOffset>,
7746    ) -> Range<MultiBufferOffset> {
7747        if buffer_range.start < self.buffer_offset {
7748            log::warn!(
7749                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7750            );
7751            return self.offset..self.offset;
7752        }
7753        let overshoot = buffer_range.start - self.buffer_offset;
7754        let excerpt_offset = self.excerpt_offset + overshoot;
7755        let excerpt_seek_dim = excerpt_offset;
7756        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7757        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7758            log::warn!(
7759                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7760            );
7761            return self.offset..self.offset;
7762        }
7763        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7764        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7765
7766        let end = if buffer_range.start < buffer_range.end {
7767            let overshoot = buffer_range.end - self.buffer_offset;
7768            let excerpt_offset = self.excerpt_offset + overshoot;
7769            let excerpt_seek_dim = excerpt_offset;
7770            self.diff_transforms
7771                .seek_forward(&excerpt_seek_dim, Bias::Right);
7772            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7773            // todo(lw): Clamp end to the excerpt boundaries
7774            self.diff_transforms.start().output_dimension.0 + overshoot
7775        } else {
7776            start
7777        };
7778
7779        start..end
7780    }
7781
7782    /// Returns true if the entirety of the given range is in the buffer's excerpt
7783    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7784        range.start >= self.excerpt.buffer_start_offset()
7785            && range.end <= self.excerpt.buffer_end_offset()
7786    }
7787
7788    /// Returns true if any part of the given range is in the buffer's excerpt
7789    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7790        range.start <= self.excerpt.buffer_end_offset()
7791            && range.end >= self.excerpt.buffer_start_offset()
7792    }
7793
7794    pub fn max_buffer_row(&self) -> u32 {
7795        self.excerpt.max_buffer_row
7796    }
7797}
7798
7799impl ExcerptId {
7800    pub fn min() -> Self {
7801        Self(0)
7802    }
7803
7804    pub fn max() -> Self {
7805        Self(u32::MAX)
7806    }
7807
7808    pub fn to_proto(self) -> u64 {
7809        self.0 as _
7810    }
7811
7812    pub fn from_proto(proto: u64) -> Self {
7813        Self(proto as _)
7814    }
7815
7816    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7817        let a = snapshot.excerpt_locator_for_id(*self);
7818        let b = snapshot.excerpt_locator_for_id(*other);
7819        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7820    }
7821}
7822
7823impl From<ExcerptId> for usize {
7824    fn from(val: ExcerptId) -> Self {
7825        val.0 as usize
7826    }
7827}
7828
7829impl fmt::Debug for Excerpt {
7830    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7831        f.debug_struct("Excerpt")
7832            .field("id", &self.id)
7833            .field("locator", &self.locator)
7834            .field("buffer_id", &self.buffer_id)
7835            .field("range", &self.range)
7836            .field("text_summary", &self.text_summary)
7837            .field("has_trailing_newline", &self.has_trailing_newline)
7838            .finish()
7839    }
7840}
7841
7842impl sum_tree::Item for Excerpt {
7843    type Summary = ExcerptSummary;
7844
7845    fn summary(&self, _cx: ()) -> Self::Summary {
7846        let mut text = self.text_summary;
7847        if self.has_trailing_newline {
7848            text += TextSummary::from("\n");
7849        }
7850        ExcerptSummary {
7851            excerpt_id: self.id,
7852            excerpt_locator: self.locator.clone(),
7853            widest_line_number: self.max_buffer_row,
7854            text: text.into(),
7855            count: 1,
7856        }
7857    }
7858}
7859
7860impl sum_tree::Item for ExcerptIdMapping {
7861    type Summary = ExcerptId;
7862
7863    fn summary(&self, _cx: ()) -> Self::Summary {
7864        self.id
7865    }
7866}
7867
7868impl sum_tree::KeyedItem for ExcerptIdMapping {
7869    type Key = ExcerptId;
7870
7871    fn key(&self) -> Self::Key {
7872        self.id
7873    }
7874}
7875
7876impl DiffTransform {
7877    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7878        match self {
7879            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7880            DiffTransform::BufferContent {
7881                inserted_hunk_info, ..
7882            } => *inserted_hunk_info,
7883        }
7884    }
7885}
7886
7887impl sum_tree::Item for DiffTransform {
7888    type Summary = DiffTransformSummary;
7889
7890    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7891        match self {
7892            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7893                input: *summary,
7894                output: *summary,
7895            },
7896            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7897                input: MBTextSummary::default(),
7898                output: summary.into(),
7899            },
7900        }
7901    }
7902}
7903
7904impl DiffTransformSummary {
7905    fn excerpt_len(&self) -> ExcerptOffset {
7906        ExcerptDimension(self.input.len)
7907    }
7908}
7909
7910impl sum_tree::ContextLessSummary for DiffTransformSummary {
7911    fn zero() -> Self {
7912        DiffTransformSummary {
7913            input: MBTextSummary::default(),
7914            output: MBTextSummary::default(),
7915        }
7916    }
7917
7918    fn add_summary(&mut self, other: &Self) {
7919        self.input += other.input;
7920        self.output += other.output;
7921    }
7922}
7923
7924impl sum_tree::ContextLessSummary for ExcerptId {
7925    fn zero() -> Self {
7926        Self(0)
7927    }
7928
7929    fn add_summary(&mut self, summary: &Self) {
7930        *self = cmp::max(*self, *summary);
7931    }
7932}
7933
7934impl sum_tree::ContextLessSummary for ExcerptSummary {
7935    fn zero() -> Self {
7936        Self::default()
7937    }
7938
7939    fn add_summary(&mut self, summary: &Self) {
7940        debug_assert!(
7941            summary.excerpt_locator > self.excerpt_locator
7942                || self.excerpt_locator == Locator::min(),
7943            "Excerpt locators must be in ascending order: {:?} > {:?}",
7944            summary.excerpt_locator,
7945            self.excerpt_locator
7946        );
7947        self.excerpt_locator = summary.excerpt_locator.clone();
7948        self.text += summary.text;
7949        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7950        self.count += summary.count;
7951    }
7952}
7953
7954impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7955    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7956        Ord::cmp(&Some(self), cursor_location)
7957    }
7958}
7959
7960impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7961    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7962        Ord::cmp(self, &cursor_location.excerpt_locator)
7963    }
7964}
7965
7966impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7967where
7968    MBD: MultiBufferDimension + Default,
7969{
7970    fn zero(_: ()) -> Self {
7971        ExcerptDimension(MBD::default())
7972    }
7973
7974    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7975        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7976    }
7977}
7978
7979impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7980    fn zero(_cx: ()) -> Self {
7981        Default::default()
7982    }
7983
7984    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7985        *self = Some(&summary.excerpt_locator);
7986    }
7987}
7988
7989impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7990    fn zero(_cx: ()) -> Self {
7991        Default::default()
7992    }
7993
7994    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7995        *self = Some(summary.excerpt_id);
7996    }
7997}
7998
7999#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8000struct OutputDimension<T>(T);
8001
8002impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
8003    fn eq(&self, other: &T) -> bool {
8004        self.0 == *other
8005    }
8006}
8007
8008impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
8009    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8010        self.0.partial_cmp(other)
8011    }
8012}
8013
8014impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
8015where
8016    T: ops::Sub<U, Output = R>,
8017{
8018    type Output = R;
8019
8020    fn sub(self, other: OutputDimension<U>) -> Self::Output {
8021        self.0 - other.0
8022    }
8023}
8024
8025impl<R, T, U> ops::Add<U> for OutputDimension<T>
8026where
8027    T: ops::Add<U, Output = R>,
8028{
8029    type Output = OutputDimension<R>;
8030
8031    fn add(self, other: U) -> Self::Output {
8032        OutputDimension(self.0 + other)
8033    }
8034}
8035
8036impl<T, U> AddAssign<U> for OutputDimension<T>
8037where
8038    T: AddAssign<U>,
8039{
8040    fn add_assign(&mut self, other: U) {
8041        self.0 += other;
8042    }
8043}
8044
8045impl<T, U> SubAssign<U> for OutputDimension<T>
8046where
8047    T: SubAssign<U>,
8048{
8049    fn sub_assign(&mut self, other: U) {
8050        self.0 -= other;
8051    }
8052}
8053
8054#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
8055struct ExcerptDimension<T>(T);
8056
8057impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
8058    fn eq(&self, other: &T) -> bool {
8059        self.0 == *other
8060    }
8061}
8062
8063impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
8064    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
8065        self.0.partial_cmp(other)
8066    }
8067}
8068
8069impl ExcerptOffset {
8070    fn saturating_sub(self, other: ExcerptOffset) -> usize {
8071        self.0.saturating_sub(other.0)
8072    }
8073}
8074
8075impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
8076where
8077    T: ops::Sub<U, Output = R>,
8078{
8079    type Output = R;
8080
8081    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
8082        self.0 - other.0
8083    }
8084}
8085
8086impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
8087where
8088    T: ops::Add<U, Output = R>,
8089{
8090    type Output = ExcerptDimension<R>;
8091
8092    fn add(self, other: U) -> Self::Output {
8093        ExcerptDimension(self.0 + other)
8094    }
8095}
8096
8097impl<T, U> AddAssign<U> for ExcerptDimension<T>
8098where
8099    T: AddAssign<U>,
8100{
8101    fn add_assign(&mut self, other: U) {
8102        self.0 += other;
8103    }
8104}
8105
8106impl<T, U> SubAssign<U> for ExcerptDimension<T>
8107where
8108    T: SubAssign<U>,
8109{
8110    fn sub_assign(&mut self, other: U) {
8111        self.0 -= other;
8112    }
8113}
8114
8115impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
8116    fn zero(_: ()) -> Self {
8117        MultiBufferOffset::ZERO
8118    }
8119
8120    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8121        *self += summary.output.len;
8122    }
8123}
8124
8125impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
8126    for ExcerptDimension<MBD>
8127where
8128    MBD: MultiBufferDimension + Ord,
8129{
8130    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
8131        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
8132    }
8133}
8134
8135impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8136    for ExcerptDimension<MBD>
8137where
8138    MBD: MultiBufferDimension + Ord,
8139{
8140    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8141        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8142    }
8143}
8144
8145impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8146    for ExcerptDimension<MBD>
8147{
8148    fn zero(_: ()) -> Self {
8149        ExcerptDimension(MBD::default())
8150    }
8151
8152    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8153        self.0.add_mb_text_summary(&summary.input)
8154    }
8155}
8156
8157impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8158    for OutputDimension<MBD>
8159where
8160    MBD: MultiBufferDimension + Ord,
8161{
8162    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8163        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8164    }
8165}
8166
8167impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8168    for OutputDimension<MBD>
8169{
8170    fn zero(_: ()) -> Self {
8171        OutputDimension(MBD::default())
8172    }
8173
8174    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8175        self.0.add_mb_text_summary(&summary.output)
8176    }
8177}
8178
8179impl MultiBufferRows<'_> {
8180    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8181        self.point = Point::new(row, 0);
8182        self.cursor.seek(&self.point);
8183    }
8184}
8185
8186impl Iterator for MultiBufferRows<'_> {
8187    type Item = RowInfo;
8188
8189    fn next(&mut self) -> Option<Self::Item> {
8190        if self.is_empty && self.point.row == 0 {
8191            self.point += Point::new(1, 0);
8192            return Some(RowInfo {
8193                buffer_id: None,
8194                buffer_row: Some(0),
8195                multibuffer_row: Some(MultiBufferRow(0)),
8196                diff_status: None,
8197                expand_info: None,
8198                wrapped_buffer_row: None,
8199            });
8200        }
8201
8202        let mut region = self.cursor.region()?.clone();
8203        while self.point >= region.range.end {
8204            self.cursor.next();
8205            if let Some(next_region) = self.cursor.region() {
8206                region = next_region.clone();
8207            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8208                let multibuffer_row = MultiBufferRow(self.point.row);
8209                let last_excerpt = self
8210                    .cursor
8211                    .excerpts
8212                    .item()
8213                    .or(self.cursor.excerpts.prev_item())?;
8214                let last_row = last_excerpt
8215                    .range
8216                    .context
8217                    .end
8218                    .to_point(&last_excerpt.buffer)
8219                    .row;
8220
8221                let first_row = last_excerpt
8222                    .range
8223                    .context
8224                    .start
8225                    .to_point(&last_excerpt.buffer)
8226                    .row;
8227
8228                let expand_info = if self.is_singleton {
8229                    None
8230                } else {
8231                    let needs_expand_up = first_row == last_row
8232                        && last_row > 0
8233                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8234                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8235
8236                    if needs_expand_up && needs_expand_down {
8237                        Some(ExpandExcerptDirection::UpAndDown)
8238                    } else if needs_expand_up {
8239                        Some(ExpandExcerptDirection::Up)
8240                    } else if needs_expand_down {
8241                        Some(ExpandExcerptDirection::Down)
8242                    } else {
8243                        None
8244                    }
8245                    .map(|direction| ExpandInfo {
8246                        direction,
8247                        excerpt_id: last_excerpt.id,
8248                    })
8249                };
8250                self.point += Point::new(1, 0);
8251                return Some(RowInfo {
8252                    buffer_id: Some(last_excerpt.buffer_id),
8253                    buffer_row: Some(last_row),
8254                    multibuffer_row: Some(multibuffer_row),
8255                    diff_status: None,
8256                    wrapped_buffer_row: None,
8257                    expand_info,
8258                });
8259            } else {
8260                return None;
8261            };
8262        }
8263
8264        let overshoot = self.point - region.range.start;
8265        let buffer_point = region.buffer_range.start + overshoot;
8266        let expand_info = if self.is_singleton {
8267            None
8268        } else {
8269            let needs_expand_up = self.point.row == region.range.start.row
8270                && self.cursor.is_at_start_of_excerpt()
8271                && buffer_point.row > 0;
8272            let needs_expand_down = (region.excerpt.has_trailing_newline
8273                && self.point.row + 1 == region.range.end.row
8274                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8275                && self.cursor.is_at_end_of_excerpt()
8276                && buffer_point.row < region.buffer.max_point().row;
8277
8278            if needs_expand_up && needs_expand_down {
8279                Some(ExpandExcerptDirection::UpAndDown)
8280            } else if needs_expand_up {
8281                Some(ExpandExcerptDirection::Up)
8282            } else if needs_expand_down {
8283                Some(ExpandExcerptDirection::Down)
8284            } else {
8285                None
8286            }
8287            .map(|direction| ExpandInfo {
8288                direction,
8289                excerpt_id: region.excerpt.id,
8290            })
8291        };
8292
8293        let result = Some(RowInfo {
8294            buffer_id: Some(region.buffer.remote_id()),
8295            buffer_row: Some(buffer_point.row),
8296            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8297            diff_status: region
8298                .diff_hunk_status
8299                .filter(|_| self.point < region.range.end),
8300            expand_info,
8301            wrapped_buffer_row: None,
8302        });
8303        self.point += Point::new(1, 0);
8304        result
8305    }
8306}
8307
8308impl<'a> MultiBufferChunks<'a> {
8309    pub fn offset(&self) -> MultiBufferOffset {
8310        self.range.start
8311    }
8312
8313    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8314        self.diff_transforms.seek(&range.end, Bias::Right);
8315        let mut excerpt_end = self.diff_transforms.start().1;
8316        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8317            let overshoot = range.end - self.diff_transforms.start().0;
8318            excerpt_end += overshoot;
8319        }
8320
8321        self.diff_transforms.seek(&range.start, Bias::Right);
8322        let mut excerpt_start = self.diff_transforms.start().1;
8323        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8324            let overshoot = range.start - self.diff_transforms.start().0;
8325            excerpt_start += overshoot;
8326        }
8327
8328        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8329        self.buffer_chunk.take();
8330        self.range = range;
8331    }
8332
8333    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8334        self.excerpt_offset_range = new_range.clone();
8335        self.excerpts.seek(&new_range.start, Bias::Right);
8336        if let Some(excerpt) = self.excerpts.item() {
8337            let excerpt_start = *self.excerpts.start();
8338            if let Some(excerpt_chunks) = self
8339                .excerpt_chunks
8340                .as_mut()
8341                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8342            {
8343                excerpt.seek_chunks(
8344                    excerpt_chunks,
8345                    (self.excerpt_offset_range.start - excerpt_start)
8346                        ..(self.excerpt_offset_range.end - excerpt_start),
8347                );
8348            } else {
8349                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8350                    (self.excerpt_offset_range.start - excerpt_start)
8351                        ..(self.excerpt_offset_range.end - excerpt_start),
8352                    self.language_aware,
8353                ));
8354            }
8355        } else {
8356            self.excerpt_chunks = None;
8357        }
8358    }
8359
8360    #[ztracing::instrument(skip_all)]
8361    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8362        loop {
8363            if self.excerpt_offset_range.is_empty() {
8364                return None;
8365            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8366                self.excerpt_offset_range.start += chunk.text.len();
8367                return Some(chunk);
8368            } else {
8369                self.excerpts.next();
8370                let excerpt = self.excerpts.item()?;
8371                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8372                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8373                    self.language_aware,
8374                ));
8375            }
8376        }
8377    }
8378}
8379
8380impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8381    type Item = &'a str;
8382
8383    fn next(&mut self) -> Option<Self::Item> {
8384        let mut region = self.cursor.region()?;
8385        if self.offset == region.range.start {
8386            self.cursor.prev();
8387            region = self.cursor.region()?;
8388            let start_overshoot = self.start.saturating_sub(region.range.start);
8389            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8390                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8391            ));
8392        }
8393
8394        if self.offset == region.range.end && region.has_trailing_newline {
8395            self.offset -= 1;
8396            Some("\n")
8397        } else {
8398            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8399            self.offset -= chunk.len();
8400            Some(chunk)
8401        }
8402    }
8403}
8404
8405impl<'a> Iterator for MultiBufferChunks<'a> {
8406    type Item = Chunk<'a>;
8407
8408    #[ztracing::instrument(skip_all)]
8409    fn next(&mut self) -> Option<Chunk<'a>> {
8410        if self.range.start >= self.range.end {
8411            return None;
8412        }
8413        if self.range.start == self.diff_transforms.end().0 {
8414            self.diff_transforms.next();
8415        }
8416
8417        let diff_transform_start = self.diff_transforms.start().0;
8418        let diff_transform_end = self.diff_transforms.end().0;
8419        debug_assert!(
8420            self.range.start < diff_transform_end,
8421            "{:?} < {:?} of ({1:?}..{2:?})",
8422            self.range.start,
8423            diff_transform_end,
8424            diff_transform_start
8425        );
8426
8427        let diff_transform = self.diff_transforms.item()?;
8428        match diff_transform {
8429            DiffTransform::BufferContent { .. } => {
8430                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8431                    chunk
8432                } else {
8433                    let chunk = self.next_excerpt_chunk().unwrap();
8434                    self.buffer_chunk.insert(chunk)
8435                };
8436
8437                let chunk_end = self.range.start + chunk.text.len();
8438                let diff_transform_end = diff_transform_end.min(self.range.end);
8439
8440                if diff_transform_end < chunk_end {
8441                    let split_idx = diff_transform_end - self.range.start;
8442                    let (before, after) = chunk.text.split_at(split_idx);
8443                    self.range.start = diff_transform_end;
8444                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8445                    let chars = chunk.chars & mask;
8446                    let tabs = chunk.tabs & mask;
8447                    let newlines = chunk.newlines & mask;
8448
8449                    chunk.text = after;
8450                    chunk.chars = chunk.chars >> split_idx;
8451                    chunk.tabs = chunk.tabs >> split_idx;
8452                    chunk.newlines = chunk.newlines >> split_idx;
8453
8454                    Some(Chunk {
8455                        text: before,
8456                        chars,
8457                        tabs,
8458                        newlines,
8459                        ..chunk.clone()
8460                    })
8461                } else {
8462                    self.range.start = chunk_end;
8463                    self.buffer_chunk.take()
8464                }
8465            }
8466            DiffTransform::DeletedHunk {
8467                buffer_id,
8468                base_text_byte_range,
8469                has_trailing_newline,
8470                ..
8471            } => {
8472                let base_text_start =
8473                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8474                let base_text_end =
8475                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8476                let base_text_end = base_text_end.min(base_text_byte_range.end);
8477
8478                let mut chunks = if let Some((_, mut chunks)) = self
8479                    .diff_base_chunks
8480                    .take()
8481                    .filter(|(id, _)| id == buffer_id)
8482                {
8483                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8484                    {
8485                        chunks.seek(base_text_start..base_text_end);
8486                    }
8487                    chunks
8488                } else {
8489                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8490                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8491                };
8492
8493                let chunk = if let Some(chunk) = chunks.next() {
8494                    self.range.start += chunk.text.len();
8495                    self.diff_base_chunks = Some((*buffer_id, chunks));
8496                    chunk
8497                } else {
8498                    debug_assert!(has_trailing_newline);
8499                    self.range.start += "\n".len();
8500                    Chunk {
8501                        text: "\n",
8502                        chars: 1u128,
8503                        newlines: 1u128,
8504                        ..Default::default()
8505                    }
8506                };
8507                Some(chunk)
8508            }
8509        }
8510    }
8511}
8512
8513impl MultiBufferBytes<'_> {
8514    fn consume(&mut self, len: usize) {
8515        self.range.start += len;
8516        self.chunk = &self.chunk[len..];
8517
8518        if !self.range.is_empty() && self.chunk.is_empty() {
8519            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8520                self.chunk = chunk;
8521            } else if self.has_trailing_newline {
8522                self.has_trailing_newline = false;
8523                self.chunk = b"\n";
8524            } else {
8525                self.cursor.next();
8526                if let Some(region) = self.cursor.region() {
8527                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8528                        region.buffer_range.start
8529                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8530                                .min(region.buffer_range.end),
8531                    );
8532                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8533                    self.excerpt_bytes = Some(excerpt_bytes);
8534                    self.has_trailing_newline =
8535                        region.has_trailing_newline && self.range.end >= region.range.end;
8536                    if self.chunk.is_empty() && self.has_trailing_newline {
8537                        self.has_trailing_newline = false;
8538                        self.chunk = b"\n";
8539                    }
8540                }
8541            }
8542        }
8543    }
8544}
8545
8546impl<'a> Iterator for MultiBufferBytes<'a> {
8547    type Item = &'a [u8];
8548
8549    fn next(&mut self) -> Option<Self::Item> {
8550        let chunk = self.chunk;
8551        if chunk.is_empty() {
8552            None
8553        } else {
8554            self.consume(chunk.len());
8555            Some(chunk)
8556        }
8557    }
8558}
8559
8560impl io::Read for MultiBufferBytes<'_> {
8561    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8562        let len = cmp::min(buf.len(), self.chunk.len());
8563        buf[..len].copy_from_slice(&self.chunk[..len]);
8564        if len > 0 {
8565            self.consume(len);
8566        }
8567        Ok(len)
8568    }
8569}
8570
8571impl io::Read for ReversedMultiBufferBytes<'_> {
8572    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8573        let len = cmp::min(buf.len(), self.chunk.len());
8574        buf[..len].copy_from_slice(&self.chunk[..len]);
8575        buf[..len].reverse();
8576        if len > 0 {
8577            self.range.end -= len;
8578            self.chunk = &self.chunk[..self.chunk.len() - len];
8579            if !self.range.is_empty()
8580                && self.chunk.is_empty()
8581                && let Some(chunk) = self.chunks.next()
8582            {
8583                self.chunk = chunk.as_bytes();
8584            }
8585        }
8586        Ok(len)
8587    }
8588}
8589
8590impl<'a> Iterator for ExcerptChunks<'a> {
8591    type Item = Chunk<'a>;
8592
8593    fn next(&mut self) -> Option<Self::Item> {
8594        if let Some(chunk) = self.content_chunks.next() {
8595            return Some(chunk);
8596        }
8597
8598        if self.has_footer {
8599            let text = "\n";
8600            let chars = 0b1;
8601            let newlines = 0b1;
8602            self.has_footer = false;
8603            return Some(Chunk {
8604                text,
8605                chars,
8606                newlines,
8607                ..Default::default()
8608            });
8609        }
8610
8611        None
8612    }
8613}
8614
8615impl ToOffset for Point {
8616    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8617        snapshot.point_to_offset(*self)
8618    }
8619    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8620        snapshot.point_to_offset_utf16(*self)
8621    }
8622}
8623
8624impl ToOffset for MultiBufferOffset {
8625    #[track_caller]
8626    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8627        assert!(
8628            *self <= snapshot.len(),
8629            "offset {} is greater than the snapshot.len() {}",
8630            self.0,
8631            snapshot.len().0,
8632        );
8633        *self
8634    }
8635    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8636        snapshot.offset_to_offset_utf16(*self)
8637    }
8638}
8639
8640impl ToOffset for MultiBufferOffsetUtf16 {
8641    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8642        snapshot.offset_utf16_to_offset(*self)
8643    }
8644
8645    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8646        *self
8647    }
8648}
8649
8650impl ToOffset for PointUtf16 {
8651    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8652        snapshot.point_utf16_to_offset(*self)
8653    }
8654    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8655        snapshot.point_utf16_to_offset_utf16(*self)
8656    }
8657}
8658
8659impl ToPoint for MultiBufferOffset {
8660    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8661        snapshot.offset_to_point(*self)
8662    }
8663    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8664        snapshot.offset_to_point_utf16(*self)
8665    }
8666}
8667
8668impl ToPoint for Point {
8669    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8670        *self
8671    }
8672    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8673        snapshot.point_to_point_utf16(*self)
8674    }
8675}
8676
8677impl ToPoint for PointUtf16 {
8678    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8679        snapshot.point_utf16_to_point(*self)
8680    }
8681    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8682        *self
8683    }
8684}
8685
8686impl From<ExcerptId> for EntityId {
8687    fn from(id: ExcerptId) -> Self {
8688        EntityId::from(id.0 as u64)
8689    }
8690}
8691
8692#[cfg(debug_assertions)]
8693pub mod debug {
8694    use super::*;
8695
8696    pub trait ToMultiBufferDebugRanges {
8697        fn to_multi_buffer_debug_ranges(
8698            &self,
8699            snapshot: &MultiBufferSnapshot,
8700        ) -> Vec<Range<MultiBufferOffset>>;
8701    }
8702
8703    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8704        fn to_multi_buffer_debug_ranges(
8705            &self,
8706            snapshot: &MultiBufferSnapshot,
8707        ) -> Vec<Range<MultiBufferOffset>> {
8708            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8709        }
8710    }
8711
8712    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8713        fn to_multi_buffer_debug_ranges(
8714            &self,
8715            snapshot: &MultiBufferSnapshot,
8716        ) -> Vec<Range<MultiBufferOffset>> {
8717            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8718                .to_multi_buffer_debug_ranges(snapshot)
8719        }
8720    }
8721
8722    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8723        fn to_multi_buffer_debug_ranges(
8724            &self,
8725            snapshot: &MultiBufferSnapshot,
8726        ) -> Vec<Range<MultiBufferOffset>> {
8727            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8728        }
8729    }
8730
8731    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8732        fn to_multi_buffer_debug_ranges(
8733            &self,
8734            snapshot: &MultiBufferSnapshot,
8735        ) -> Vec<Range<MultiBufferOffset>> {
8736            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8737        }
8738    }
8739
8740    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8741        fn to_multi_buffer_debug_ranges(
8742            &self,
8743            snapshot: &MultiBufferSnapshot,
8744        ) -> Vec<Range<MultiBufferOffset>> {
8745            self.iter()
8746                .map(|item| {
8747                    let offset = item.to_offset(snapshot);
8748                    offset..offset
8749                })
8750                .collect()
8751        }
8752    }
8753
8754    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8755        fn to_multi_buffer_debug_ranges(
8756            &self,
8757            snapshot: &MultiBufferSnapshot,
8758        ) -> Vec<Range<MultiBufferOffset>> {
8759            self.iter()
8760                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8761                .collect()
8762        }
8763    }
8764}