multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod transaction;
   6
   7use self::transaction::History;
   8
   9pub use anchor::{Anchor, AnchorRangeExt};
  10
  11use anyhow::{Result, anyhow};
  12use buffer_diff::{
  13    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffChanged, DiffHunk,
  14    DiffHunkSecondaryStatus, DiffHunkStatus, DiffHunkStatusKind,
  15};
  16use clock::ReplicaId;
  17use collections::{BTreeMap, Bound, HashMap, HashSet};
  18use gpui::{App, Context, Entity, EntityId, EventEmitter};
  19use itertools::Itertools;
  20use language::{
  21    AutoindentMode, BracketMatch, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability,
  22    CharClassifier, CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, File,
  23    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  24    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  25    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  26    language_settings::{LanguageSettings, language_settings},
  27};
  28
  29#[cfg(any(test, feature = "test-support"))]
  30use gpui::AppContext as _;
  31
  32use rope::DimensionPair;
  33use smallvec::SmallVec;
  34use smol::future::yield_now;
  35use std::{
  36    any::type_name,
  37    borrow::Cow,
  38    cell::{Cell, OnceCell, Ref, RefCell},
  39    cmp, fmt,
  40    future::Future,
  41    io,
  42    iter::{self, FromIterator},
  43    mem,
  44    ops::{self, Add, AddAssign, ControlFlow, Range, RangeBounds, Sub, SubAssign},
  45    rc::Rc,
  46    str,
  47    sync::{Arc, OnceLock},
  48    time::Duration,
  49};
  50use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  51use text::{
  52    BufferId, Edit, LineIndent, TextSummary,
  53    locator::Locator,
  54    subscription::{Subscription, Topic},
  55};
  56use theme::SyntaxTheme;
  57use util::post_inc;
  58use ztracing::instrument;
  59
  60pub use self::path_key::PathKey;
  61
  62pub static EXCERPT_CONTEXT_LINES: OnceLock<fn(&App) -> u32> = OnceLock::new();
  63
  64pub fn excerpt_context_lines(cx: &App) -> u32 {
  65    EXCERPT_CONTEXT_LINES.get().map(|f| f(cx)).unwrap_or(2)
  66}
  67
  68#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  69pub struct ExcerptId(u32);
  70
  71/// One or more [`Buffers`](Buffer) being edited in a single view.
  72///
  73/// See <https://zed.dev/features#multi-buffers>
  74pub struct MultiBuffer {
  75    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  76    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  77    snapshot: RefCell<MultiBufferSnapshot>,
  78    /// Contains the state of the buffers being edited
  79    buffers: BTreeMap<BufferId, BufferState>,
  80    /// Mapping from path keys to their excerpts.
  81    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  82    /// Mapping from excerpt IDs to their path key.
  83    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  84    /// Mapping from buffer IDs to their diff states
  85    diffs: HashMap<BufferId, DiffState>,
  86    subscriptions: Topic<MultiBufferOffset>,
  87    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  88    singleton: bool,
  89    /// The history of the multi-buffer.
  90    history: History,
  91    /// The explicit title of the multi-buffer.
  92    /// If `None`, it will be derived from the underlying path or content.
  93    title: Option<String>,
  94    /// The writing capability of the multi-buffer.
  95    capability: Capability,
  96    buffer_changed_since_sync: Rc<Cell<bool>>,
  97}
  98
  99#[derive(Clone, Debug, PartialEq, Eq)]
 100pub enum Event {
 101    ExcerptsAdded {
 102        buffer: Entity<Buffer>,
 103        predecessor: ExcerptId,
 104        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 105    },
 106    ExcerptsRemoved {
 107        ids: Vec<ExcerptId>,
 108        removed_buffer_ids: Vec<BufferId>,
 109    },
 110    ExcerptsExpanded {
 111        ids: Vec<ExcerptId>,
 112    },
 113    ExcerptsEdited {
 114        excerpt_ids: Vec<ExcerptId>,
 115        buffer_ids: Vec<BufferId>,
 116    },
 117    DiffHunksToggled,
 118    Edited {
 119        edited_buffer: Option<Entity<Buffer>>,
 120    },
 121    TransactionUndone {
 122        transaction_id: TransactionId,
 123    },
 124    Reloaded,
 125    LanguageChanged(BufferId, bool),
 126    Reparsed(BufferId),
 127    Saved,
 128    FileHandleChanged,
 129    DirtyChanged,
 130    DiagnosticsUpdated,
 131    BufferDiffChanged,
 132}
 133
 134/// A diff hunk, representing a range of consequent lines in a multibuffer.
 135#[derive(Debug, Clone, PartialEq, Eq)]
 136pub struct MultiBufferDiffHunk {
 137    /// The row range in the multibuffer where this diff hunk appears.
 138    pub row_range: Range<MultiBufferRow>,
 139    /// The buffer ID that this hunk belongs to.
 140    pub buffer_id: BufferId,
 141    /// The range of the underlying buffer that this hunk corresponds to.
 142    pub buffer_range: Range<text::Anchor>,
 143    /// The excerpt that contains the diff hunk.
 144    pub excerpt_id: ExcerptId,
 145    /// The range within the buffer's diff base that this hunk corresponds to.
 146    pub diff_base_byte_range: Range<BufferOffset>,
 147    /// The status of this hunk (added/modified/deleted and secondary status).
 148    pub status: DiffHunkStatus,
 149    /// The word diffs for this hunk.
 150    pub word_diffs: Vec<Range<MultiBufferOffset>>,
 151}
 152
 153impl MultiBufferDiffHunk {
 154    pub fn status(&self) -> DiffHunkStatus {
 155        self.status
 156    }
 157
 158    pub fn is_created_file(&self) -> bool {
 159        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 160            && self.buffer_range.start.is_min()
 161            && self.buffer_range.end.is_max()
 162    }
 163
 164    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 165        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_range.start);
 166        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_range.end);
 167        start..end
 168    }
 169}
 170
 171pub type MultiBufferPoint = Point;
 172type ExcerptOffset = ExcerptDimension<MultiBufferOffset>;
 173type ExcerptPoint = ExcerptDimension<Point>;
 174
 175#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 176#[serde(transparent)]
 177pub struct MultiBufferRow(pub u32);
 178
 179impl MultiBufferRow {
 180    pub const MIN: Self = Self(0);
 181    pub const MAX: Self = Self(u32::MAX);
 182}
 183
 184impl ops::Add<usize> for MultiBufferRow {
 185    type Output = Self;
 186
 187    fn add(self, rhs: usize) -> Self::Output {
 188        MultiBufferRow(self.0 + rhs as u32)
 189    }
 190}
 191
 192pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 193    type TextDimension: TextDimension;
 194    fn from_summary(summary: &MBTextSummary) -> Self;
 195
 196    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 197
 198    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 199}
 200
 201// todo(lw): MultiBufferPoint
 202impl MultiBufferDimension for Point {
 203    type TextDimension = Point;
 204    fn from_summary(summary: &MBTextSummary) -> Self {
 205        summary.lines
 206    }
 207
 208    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 209        *self += *other;
 210    }
 211
 212    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 213        *self += summary.lines;
 214    }
 215}
 216
 217// todo(lw): MultiBufferPointUtf16
 218impl MultiBufferDimension for PointUtf16 {
 219    type TextDimension = PointUtf16;
 220    fn from_summary(summary: &MBTextSummary) -> Self {
 221        summary.lines_utf16()
 222    }
 223
 224    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 225        *self += *other;
 226    }
 227
 228    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 229        *self += summary.lines_utf16();
 230    }
 231}
 232
 233#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 234pub struct MultiBufferOffset(pub usize);
 235
 236impl fmt::Display for MultiBufferOffset {
 237    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 238        write!(f, "{}", self.0)
 239    }
 240}
 241
 242impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 243    type Sampler = MultiBufferOffsetUniformSampler;
 244}
 245
 246pub struct MultiBufferOffsetUniformSampler {
 247    sampler: rand::distr::uniform::UniformUsize,
 248}
 249
 250impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 251    type X = MultiBufferOffset;
 252
 253    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 254    where
 255        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 256        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 257    {
 258        let low = *low_b.borrow();
 259        let high = *high_b.borrow();
 260        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 261        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 262    }
 263
 264    #[inline] // if the range is constant, this helps LLVM to do the
 265    // calculations at compile-time.
 266    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 267    where
 268        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 269        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 270    {
 271        let low = *low_b.borrow();
 272        let high = *high_b.borrow();
 273        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 274        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 275    }
 276
 277    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 278        MultiBufferOffset(self.sampler.sample(rng))
 279    }
 280}
 281impl MultiBufferDimension for MultiBufferOffset {
 282    type TextDimension = usize;
 283    fn from_summary(summary: &MBTextSummary) -> Self {
 284        summary.len
 285    }
 286
 287    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 288        self.0 += *other;
 289    }
 290
 291    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 292        *self += summary.len;
 293    }
 294}
 295impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 296    type TextDimension = OffsetUtf16;
 297    fn from_summary(summary: &MBTextSummary) -> Self {
 298        MultiBufferOffsetUtf16(summary.len_utf16)
 299    }
 300
 301    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 302        self.0 += *other;
 303    }
 304
 305    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 306        self.0 += summary.len_utf16;
 307    }
 308}
 309
 310#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 311pub struct BufferOffset(pub usize);
 312
 313impl TextDimension for BufferOffset {
 314    fn from_text_summary(summary: &TextSummary) -> Self {
 315        BufferOffset(usize::from_text_summary(summary))
 316    }
 317    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 318        BufferOffset(usize::from_chunk(chunk))
 319    }
 320    fn add_assign(&mut self, other: &Self) {
 321        TextDimension::add_assign(&mut self.0, &other.0);
 322    }
 323}
 324impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 325    fn zero(cx: ()) -> Self {
 326        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 327    }
 328
 329    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 330        usize::add_summary(&mut self.0, summary, cx);
 331    }
 332}
 333
 334impl Sub for BufferOffset {
 335    type Output = usize;
 336
 337    fn sub(self, other: BufferOffset) -> Self::Output {
 338        self.0 - other.0
 339    }
 340}
 341
 342impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 343    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 344        self.0 += other.key;
 345    }
 346}
 347
 348impl language::ToPoint for BufferOffset {
 349    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 350        self.0.to_point(snapshot)
 351    }
 352}
 353
 354impl language::ToPointUtf16 for BufferOffset {
 355    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 356        self.0.to_point_utf16(snapshot)
 357    }
 358}
 359
 360impl language::ToOffset for BufferOffset {
 361    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 362        self.0.to_offset(snapshot)
 363    }
 364}
 365
 366impl language::ToOffsetUtf16 for BufferOffset {
 367    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 368        self.0.to_offset_utf16(snapshot)
 369    }
 370}
 371
 372#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 373pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 374
 375impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 376    type Output = MultiBufferOffsetUtf16;
 377
 378    fn add(self, rhs: usize) -> Self::Output {
 379        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 380    }
 381}
 382
 383impl ops::Add<OffsetUtf16> for MultiBufferOffsetUtf16 {
 384    type Output = Self;
 385
 386    fn add(self, rhs: OffsetUtf16) -> Self::Output {
 387        MultiBufferOffsetUtf16(self.0 + rhs)
 388    }
 389}
 390
 391impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: OffsetUtf16) {
 393        self.0 += rhs;
 394    }
 395}
 396
 397impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 398    fn add_assign(&mut self, rhs: usize) {
 399        self.0.0 += rhs;
 400    }
 401}
 402
 403impl Sub for MultiBufferOffsetUtf16 {
 404    type Output = OffsetUtf16;
 405
 406    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 407        self.0 - other.0
 408    }
 409}
 410
 411impl Sub<OffsetUtf16> for MultiBufferOffsetUtf16 {
 412    type Output = MultiBufferOffsetUtf16;
 413
 414    fn sub(self, other: OffsetUtf16) -> Self::Output {
 415        MultiBufferOffsetUtf16(self.0 - other)
 416    }
 417}
 418
 419#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 420pub struct BufferOffsetUtf16(pub OffsetUtf16);
 421
 422impl MultiBufferOffset {
 423    const ZERO: Self = Self(0);
 424    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 425        self.0.saturating_sub(other.0)
 426    }
 427    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 428        MultiBufferOffset(self.0.saturating_sub(other))
 429    }
 430}
 431
 432impl ops::Sub for MultiBufferOffset {
 433    type Output = usize;
 434
 435    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 436        self.0 - other.0
 437    }
 438}
 439
 440impl ops::Sub<usize> for MultiBufferOffset {
 441    type Output = Self;
 442
 443    fn sub(self, other: usize) -> Self::Output {
 444        MultiBufferOffset(self.0 - other)
 445    }
 446}
 447
 448impl ops::SubAssign<usize> for MultiBufferOffset {
 449    fn sub_assign(&mut self, other: usize) {
 450        self.0 -= other;
 451    }
 452}
 453
 454impl ops::Add<usize> for BufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        BufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for BufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<usize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: usize) -> Self::Output {
 472        MultiBufferOffset(self.0 + rhs)
 473    }
 474}
 475
 476impl ops::AddAssign<usize> for MultiBufferOffset {
 477    fn add_assign(&mut self, other: usize) {
 478        self.0 += other;
 479    }
 480}
 481
 482impl ops::Add<isize> for MultiBufferOffset {
 483    type Output = Self;
 484
 485    fn add(self, rhs: isize) -> Self::Output {
 486        MultiBufferOffset((self.0 as isize + rhs) as usize)
 487    }
 488}
 489
 490impl ops::Add for MultiBufferOffset {
 491    type Output = Self;
 492
 493    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 494        MultiBufferOffset(self.0 + rhs.0)
 495    }
 496}
 497
 498impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 499    fn add_assign(&mut self, other: MultiBufferOffset) {
 500        self.0 += other.0;
 501    }
 502}
 503
 504pub trait ToOffset: 'static + fmt::Debug {
 505    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 506    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 507}
 508
 509pub trait ToPoint: 'static + fmt::Debug {
 510    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 511    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 512}
 513
 514struct BufferState {
 515    buffer: Entity<Buffer>,
 516    last_version: RefCell<clock::Global>,
 517    last_non_text_state_update_count: Cell<usize>,
 518    // Note, any changes to this field value require updating snapshot.buffer_locators as well
 519    excerpts: Vec<Locator>,
 520    _subscriptions: [gpui::Subscription; 2],
 521}
 522
 523struct DiffState {
 524    diff: Entity<BufferDiff>,
 525    is_inverted: bool,
 526    _subscription: gpui::Subscription,
 527}
 528
 529impl DiffState {
 530    fn snapshot(&self, cx: &App) -> DiffStateSnapshot {
 531        DiffStateSnapshot {
 532            diff: self.diff.read(cx).snapshot(cx),
 533            is_inverted: self.is_inverted,
 534        }
 535    }
 536}
 537
 538#[derive(Clone)]
 539struct DiffStateSnapshot {
 540    diff: BufferDiffSnapshot,
 541    is_inverted: bool,
 542}
 543
 544impl std::ops::Deref for DiffStateSnapshot {
 545    type Target = BufferDiffSnapshot;
 546
 547    fn deref(&self) -> &Self::Target {
 548        &self.diff
 549    }
 550}
 551
 552impl DiffState {
 553    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 554        DiffState {
 555            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 556                BufferDiffEvent::DiffChanged(DiffChanged {
 557                    changed_range,
 558                    base_text_changed_range: _,
 559                    extended_range,
 560                }) => {
 561                    let use_extended = this.snapshot.borrow().use_extended_diff_range;
 562                    let range = if use_extended {
 563                        extended_range.clone()
 564                    } else {
 565                        changed_range.clone()
 566                    };
 567                    if let Some(range) = range {
 568                        this.buffer_diff_changed(diff, range, cx)
 569                    }
 570                    cx.emit(Event::BufferDiffChanged);
 571                }
 572                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 573                _ => {}
 574            }),
 575            diff,
 576            is_inverted: false,
 577        }
 578    }
 579
 580    fn new_inverted(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 581        DiffState {
 582            _subscription: cx.subscribe(&diff, {
 583                move |this, diff, event, cx| match event {
 584                    BufferDiffEvent::DiffChanged(DiffChanged {
 585                        changed_range: _,
 586                        base_text_changed_range,
 587                        extended_range: _,
 588                    }) => {
 589                        if let Some(base_text_changed_range) = base_text_changed_range.clone() {
 590                            this.inverted_buffer_diff_changed(diff, base_text_changed_range, cx)
 591                        }
 592                        cx.emit(Event::BufferDiffChanged);
 593                    }
 594                    BufferDiffEvent::LanguageChanged => {
 595                        this.inverted_buffer_diff_language_changed(diff, cx)
 596                    }
 597                    _ => {}
 598                }
 599            }),
 600            diff,
 601            is_inverted: true,
 602        }
 603    }
 604}
 605
 606/// The contents of a [`MultiBuffer`] at a single point in time.
 607#[derive(Clone, Default)]
 608pub struct MultiBufferSnapshot {
 609    excerpts: SumTree<Excerpt>,
 610    buffer_locators: TreeMap<BufferId, Arc<[Locator]>>,
 611    diffs: TreeMap<BufferId, DiffStateSnapshot>,
 612    diff_transforms: SumTree<DiffTransform>,
 613    excerpt_ids: SumTree<ExcerptIdMapping>,
 614    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 615    non_text_state_update_count: usize,
 616    edit_count: usize,
 617    is_dirty: bool,
 618    has_deleted_file: bool,
 619    has_conflict: bool,
 620    has_inverted_diff: bool,
 621    singleton: bool,
 622    trailing_excerpt_update_count: usize,
 623    all_diff_hunks_expanded: bool,
 624    show_deleted_hunks: bool,
 625    use_extended_diff_range: bool,
 626    show_headers: bool,
 627}
 628
 629// follower: None
 630// - BufferContent(Some)
 631// - BufferContent(None)
 632// - DeletedHunk
 633//
 634// follower: Some
 635// - BufferContent(Some)
 636// - BufferContent(None)
 637
 638#[derive(Debug, Clone)]
 639enum DiffTransform {
 640    // RealText
 641    BufferContent {
 642        summary: MBTextSummary,
 643        // modified_hunk_info
 644        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 645    },
 646    // ExpandedHunkText
 647    DeletedHunk {
 648        summary: TextSummary,
 649        buffer_id: BufferId,
 650        hunk_info: DiffTransformHunkInfo,
 651        base_text_byte_range: Range<usize>,
 652        has_trailing_newline: bool,
 653    },
 654}
 655
 656#[derive(Clone, Copy, Debug)]
 657struct DiffTransformHunkInfo {
 658    excerpt_id: ExcerptId,
 659    hunk_start_anchor: text::Anchor,
 660    hunk_secondary_status: DiffHunkSecondaryStatus,
 661    is_logically_deleted: bool,
 662}
 663
 664impl Eq for DiffTransformHunkInfo {}
 665
 666impl PartialEq for DiffTransformHunkInfo {
 667    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 668        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 669    }
 670}
 671
 672impl std::hash::Hash for DiffTransformHunkInfo {
 673    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 674        self.excerpt_id.hash(state);
 675        self.hunk_start_anchor.hash(state);
 676    }
 677}
 678
 679#[derive(Clone)]
 680pub struct ExcerptInfo {
 681    pub id: ExcerptId,
 682    pub buffer: Arc<BufferSnapshot>,
 683    pub buffer_id: BufferId,
 684    pub range: ExcerptRange<text::Anchor>,
 685    pub end_row: MultiBufferRow,
 686}
 687
 688impl std::fmt::Debug for ExcerptInfo {
 689    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 690        f.debug_struct(type_name::<Self>())
 691            .field("id", &self.id)
 692            .field("buffer_id", &self.buffer_id)
 693            .field("path", &self.buffer.file().map(|f| f.path()))
 694            .field("range", &self.range)
 695            .finish()
 696    }
 697}
 698
 699/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 700#[derive(Debug)]
 701pub struct ExcerptBoundary {
 702    pub prev: Option<ExcerptInfo>,
 703    pub next: ExcerptInfo,
 704    /// The row in the `MultiBuffer` where the boundary is located
 705    pub row: MultiBufferRow,
 706}
 707
 708impl ExcerptBoundary {
 709    pub fn starts_new_buffer(&self) -> bool {
 710        match (self.prev.as_ref(), &self.next) {
 711            (None, _) => true,
 712            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 713        }
 714    }
 715}
 716
 717#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 718pub struct ExpandInfo {
 719    pub direction: ExpandExcerptDirection,
 720    pub excerpt_id: ExcerptId,
 721}
 722
 723#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 724pub struct RowInfo {
 725    pub buffer_id: Option<BufferId>,
 726    pub buffer_row: Option<u32>,
 727    pub multibuffer_row: Option<MultiBufferRow>,
 728    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 729    pub expand_info: Option<ExpandInfo>,
 730    pub wrapped_buffer_row: Option<u32>,
 731}
 732
 733/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 734#[derive(Clone)]
 735struct Excerpt {
 736    /// The unique identifier for this excerpt
 737    id: ExcerptId,
 738    /// The location of the excerpt in the [`MultiBuffer`]
 739    locator: Locator,
 740    /// The buffer being excerpted
 741    buffer_id: BufferId,
 742    /// A snapshot of the buffer being excerpted
 743    buffer: Arc<BufferSnapshot>,
 744    /// The range of the buffer to be shown in the excerpt
 745    range: ExcerptRange<text::Anchor>,
 746    /// The last row in the excerpted slice of the buffer
 747    max_buffer_row: BufferRow,
 748    /// A summary of the text in the excerpt
 749    text_summary: TextSummary,
 750    has_trailing_newline: bool,
 751}
 752
 753/// A public view into an `Excerpt` in a [`MultiBuffer`].
 754///
 755/// Contains methods for getting the [`Buffer`] of the excerpt,
 756/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 757#[derive(Clone)]
 758pub struct MultiBufferExcerpt<'a> {
 759    excerpt: &'a Excerpt,
 760    diff_transforms:
 761        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 762    /// The offset in the multibuffer considering diff transforms.
 763    offset: MultiBufferOffset,
 764    /// The offset in the multibuffer without diff transforms.
 765    excerpt_offset: ExcerptOffset,
 766    buffer_offset: BufferOffset,
 767}
 768
 769#[derive(Clone, Debug)]
 770struct ExcerptIdMapping {
 771    id: ExcerptId,
 772    locator: Locator,
 773}
 774
 775/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 776/// These ranges are relative to the buffer itself
 777#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 778pub struct ExcerptRange<T> {
 779    /// The full range of text to be shown in the excerpt.
 780    pub context: Range<T>,
 781    /// The primary range of text to be highlighted in the excerpt.
 782    /// In a multi-buffer search, this would be the text that matched the search
 783    pub primary: Range<T>,
 784}
 785
 786impl<T: Clone> ExcerptRange<T> {
 787    pub fn new(context: Range<T>) -> Self {
 788        Self {
 789            context: context.clone(),
 790            primary: context,
 791        }
 792    }
 793}
 794
 795#[derive(Clone, Debug, Default)]
 796pub struct ExcerptSummary {
 797    excerpt_id: ExcerptId,
 798    /// The location of the last [`Excerpt`] being summarized
 799    excerpt_locator: Locator,
 800    widest_line_number: u32,
 801    text: MBTextSummary,
 802}
 803
 804#[derive(Debug, Clone)]
 805pub struct DiffTransformSummary {
 806    input: MBTextSummary,
 807    output: MBTextSummary,
 808}
 809
 810/// Summary of a string of text.
 811#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 812pub struct MBTextSummary {
 813    /// Length in bytes.
 814    pub len: MultiBufferOffset,
 815    /// Length in UTF-8.
 816    pub chars: usize,
 817    /// Length in UTF-16 code units
 818    pub len_utf16: OffsetUtf16,
 819    /// A point representing the number of lines and the length of the last line.
 820    ///
 821    /// In other words, it marks the point after the last byte in the text, (if
 822    /// EOF was a character, this would be its position).
 823    pub lines: Point,
 824    /// How many `char`s are in the first line
 825    pub first_line_chars: u32,
 826    /// How many `char`s are in the last line
 827    pub last_line_chars: u32,
 828    /// How many UTF-16 code units are in the last line
 829    pub last_line_len_utf16: u32,
 830    /// The row idx of the longest row
 831    pub longest_row: u32,
 832    /// How many `char`s are in the longest row
 833    pub longest_row_chars: u32,
 834}
 835
 836impl From<TextSummary> for MBTextSummary {
 837    fn from(summary: TextSummary) -> Self {
 838        MBTextSummary {
 839            len: MultiBufferOffset(summary.len),
 840            chars: summary.chars,
 841            len_utf16: summary.len_utf16,
 842            lines: summary.lines,
 843            first_line_chars: summary.first_line_chars,
 844            last_line_chars: summary.last_line_chars,
 845            last_line_len_utf16: summary.last_line_len_utf16,
 846            longest_row: summary.longest_row,
 847            longest_row_chars: summary.longest_row_chars,
 848        }
 849    }
 850}
 851
 852impl From<MBTextSummary> for TextSummary {
 853    fn from(summary: MBTextSummary) -> Self {
 854        TextSummary {
 855            len: summary.len.0,
 856            chars: summary.chars,
 857            len_utf16: summary.len_utf16,
 858            lines: summary.lines,
 859            first_line_chars: summary.first_line_chars,
 860            last_line_chars: summary.last_line_chars,
 861            last_line_len_utf16: summary.last_line_len_utf16,
 862            longest_row: summary.longest_row,
 863            longest_row_chars: summary.longest_row_chars,
 864        }
 865    }
 866}
 867
 868impl From<&str> for MBTextSummary {
 869    fn from(text: &str) -> Self {
 870        MBTextSummary::from(TextSummary::from(text))
 871    }
 872}
 873
 874impl MultiBufferDimension for MBTextSummary {
 875    type TextDimension = TextSummary;
 876
 877    fn from_summary(summary: &MBTextSummary) -> Self {
 878        *summary
 879    }
 880
 881    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 882        *self += *summary;
 883    }
 884
 885    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 886        *self += *summary;
 887    }
 888}
 889
 890impl AddAssign for MBTextSummary {
 891    fn add_assign(&mut self, other: MBTextSummary) {
 892        let joined_chars = self.last_line_chars + other.first_line_chars;
 893        if joined_chars > self.longest_row_chars {
 894            self.longest_row = self.lines.row;
 895            self.longest_row_chars = joined_chars;
 896        }
 897        if other.longest_row_chars > self.longest_row_chars {
 898            self.longest_row = self.lines.row + other.longest_row;
 899            self.longest_row_chars = other.longest_row_chars;
 900        }
 901
 902        if self.lines.row == 0 {
 903            self.first_line_chars += other.first_line_chars;
 904        }
 905
 906        if other.lines.row == 0 {
 907            self.last_line_chars += other.first_line_chars;
 908            self.last_line_len_utf16 += other.last_line_len_utf16;
 909        } else {
 910            self.last_line_chars = other.last_line_chars;
 911            self.last_line_len_utf16 = other.last_line_len_utf16;
 912        }
 913
 914        self.chars += other.chars;
 915        self.len += other.len;
 916        self.len_utf16 += other.len_utf16;
 917        self.lines += other.lines;
 918    }
 919}
 920
 921impl AddAssign<TextSummary> for MBTextSummary {
 922    fn add_assign(&mut self, other: TextSummary) {
 923        *self += MBTextSummary::from(other);
 924    }
 925}
 926
 927impl MBTextSummary {
 928    pub fn lines_utf16(&self) -> PointUtf16 {
 929        PointUtf16 {
 930            row: self.lines.row,
 931            column: self.last_line_len_utf16,
 932        }
 933    }
 934}
 935
 936impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 937where
 938    K: MultiBufferDimension,
 939    V: MultiBufferDimension,
 940{
 941    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 942
 943    fn from_summary(summary: &MBTextSummary) -> Self {
 944        Self {
 945            key: K::from_summary(summary),
 946            value: Some(V::from_summary(summary)),
 947        }
 948    }
 949
 950    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 951        self.key.add_text_dim(&summary.key);
 952        if let Some(value) = &mut self.value {
 953            if let Some(other_value) = summary.value.as_ref() {
 954                value.add_text_dim(other_value);
 955            }
 956        }
 957    }
 958
 959    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 960        self.key.add_mb_text_summary(summary);
 961        if let Some(value) = &mut self.value {
 962            value.add_mb_text_summary(summary);
 963        }
 964    }
 965}
 966
 967#[derive(Clone)]
 968pub struct MultiBufferRows<'a> {
 969    point: Point,
 970    is_empty: bool,
 971    is_singleton: bool,
 972    cursor: MultiBufferCursor<'a, Point, Point>,
 973}
 974
 975pub struct MultiBufferChunks<'a> {
 976    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 977    diff_transforms:
 978        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 979    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
 980    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 981    buffer_chunk: Option<Chunk<'a>>,
 982    range: Range<MultiBufferOffset>,
 983    excerpt_offset_range: Range<ExcerptOffset>,
 984    excerpt_chunks: Option<ExcerptChunks<'a>>,
 985    language_aware: bool,
 986}
 987
 988pub struct ReversedMultiBufferChunks<'a> {
 989    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 990    current_chunks: Option<rope::Chunks<'a>>,
 991    start: MultiBufferOffset,
 992    offset: MultiBufferOffset,
 993}
 994
 995pub struct MultiBufferBytes<'a> {
 996    range: Range<MultiBufferOffset>,
 997    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 998    excerpt_bytes: Option<text::Bytes<'a>>,
 999    has_trailing_newline: bool,
1000    chunk: &'a [u8],
1001}
1002
1003pub struct ReversedMultiBufferBytes<'a> {
1004    range: Range<MultiBufferOffset>,
1005    chunks: ReversedMultiBufferChunks<'a>,
1006    chunk: &'a [u8],
1007}
1008
1009#[derive(Clone)]
1010struct DiffTransforms<MBD> {
1011    output_dimension: OutputDimension<MBD>,
1012    excerpt_dimension: ExcerptDimension<MBD>,
1013}
1014
1015impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
1016    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
1017        Self {
1018            output_dimension: OutputDimension::zero(cx),
1019            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
1020                cx,
1021            ),
1022        }
1023    }
1024
1025    fn add_summary(
1026        &mut self,
1027        summary: &'a DiffTransformSummary,
1028        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
1029    ) {
1030        self.output_dimension.add_summary(summary, cx);
1031        self.excerpt_dimension.add_summary(summary, cx);
1032    }
1033}
1034
1035#[derive(Clone)]
1036struct MultiBufferCursor<'a, MBD, BD> {
1037    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
1038    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
1039    diffs: &'a TreeMap<BufferId, DiffStateSnapshot>,
1040    cached_region: OnceCell<Option<MultiBufferRegion<'a, MBD, BD>>>,
1041}
1042
1043#[derive(Clone)]
1044struct MultiBufferRegion<'a, MBD, BD> {
1045    buffer: &'a BufferSnapshot,
1046    is_main_buffer: bool,
1047    diff_hunk_status: Option<DiffHunkStatus>,
1048    excerpt: &'a Excerpt,
1049    buffer_range: Range<BD>,
1050    range: Range<MBD>,
1051    has_trailing_newline: bool,
1052}
1053
1054struct ExcerptChunks<'a> {
1055    excerpt_id: ExcerptId,
1056    content_chunks: BufferChunks<'a>,
1057    has_footer: bool,
1058}
1059
1060#[derive(Debug)]
1061struct BufferEdit {
1062    range: Range<BufferOffset>,
1063    new_text: Arc<str>,
1064    is_insertion: bool,
1065    original_indent_column: Option<u32>,
1066    excerpt_id: ExcerptId,
1067}
1068
1069#[derive(Clone, Copy, Debug, PartialEq)]
1070enum DiffChangeKind {
1071    BufferEdited,
1072    DiffUpdated { base_changed: bool },
1073    ExpandOrCollapseHunks { expand: bool },
1074}
1075
1076#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1077pub enum ExpandExcerptDirection {
1078    Up,
1079    Down,
1080    UpAndDown,
1081}
1082
1083impl ExpandExcerptDirection {
1084    pub fn should_expand_up(&self) -> bool {
1085        match self {
1086            ExpandExcerptDirection::Up => true,
1087            ExpandExcerptDirection::Down => false,
1088            ExpandExcerptDirection::UpAndDown => true,
1089        }
1090    }
1091
1092    pub fn should_expand_down(&self) -> bool {
1093        match self {
1094            ExpandExcerptDirection::Up => false,
1095            ExpandExcerptDirection::Down => true,
1096            ExpandExcerptDirection::UpAndDown => true,
1097        }
1098    }
1099}
1100
1101#[derive(Clone, Debug, PartialEq)]
1102pub struct IndentGuide {
1103    pub buffer_id: BufferId,
1104    pub start_row: MultiBufferRow,
1105    pub end_row: MultiBufferRow,
1106    pub depth: u32,
1107    pub tab_size: u32,
1108    pub settings: IndentGuideSettings,
1109}
1110
1111impl IndentGuide {
1112    pub fn indent_level(&self) -> u32 {
1113        self.depth * self.tab_size
1114    }
1115}
1116
1117impl MultiBuffer {
1118    pub fn new(capability: Capability) -> Self {
1119        Self::new_(
1120            capability,
1121            MultiBufferSnapshot {
1122                show_headers: true,
1123                show_deleted_hunks: true,
1124                ..MultiBufferSnapshot::default()
1125            },
1126        )
1127    }
1128
1129    pub fn without_headers(capability: Capability) -> Self {
1130        Self::new_(
1131            capability,
1132            MultiBufferSnapshot {
1133                show_deleted_hunks: true,
1134                ..MultiBufferSnapshot::default()
1135            },
1136        )
1137    }
1138
1139    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1140        let mut this = Self::new_(
1141            buffer.read(cx).capability(),
1142            MultiBufferSnapshot {
1143                singleton: true,
1144                show_deleted_hunks: true,
1145                ..MultiBufferSnapshot::default()
1146            },
1147        );
1148        this.singleton = true;
1149        let buffer_id = buffer.read(cx).remote_id();
1150        this.push_excerpts(
1151            buffer,
1152            [ExcerptRange::new(text::Anchor::min_max_range_for_buffer(
1153                buffer_id,
1154            ))],
1155            cx,
1156        );
1157        this
1158    }
1159
1160    #[inline]
1161    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1162        Self {
1163            snapshot: RefCell::new(snapshot),
1164            buffers: Default::default(),
1165            diffs: HashMap::default(),
1166            subscriptions: Topic::default(),
1167            singleton: false,
1168            capability,
1169            title: None,
1170            excerpts_by_path: Default::default(),
1171            paths_by_excerpt: Default::default(),
1172            buffer_changed_since_sync: Default::default(),
1173            history: History::default(),
1174        }
1175    }
1176
1177    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1178        let mut buffers = BTreeMap::default();
1179        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1180        for (buffer_id, buffer_state) in self.buffers.iter() {
1181            buffer_state.buffer.update(new_cx, |buffer, _| {
1182                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1183            });
1184            buffers.insert(
1185                *buffer_id,
1186                BufferState {
1187                    buffer: buffer_state.buffer.clone(),
1188                    last_version: buffer_state.last_version.clone(),
1189                    last_non_text_state_update_count: buffer_state
1190                        .last_non_text_state_update_count
1191                        .clone(),
1192                    excerpts: buffer_state.excerpts.clone(),
1193                    _subscriptions: [
1194                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1195                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1196                    ],
1197                },
1198            );
1199        }
1200        let mut diff_bases = HashMap::default();
1201        for (buffer_id, diff) in self.diffs.iter() {
1202            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1203        }
1204        Self {
1205            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1206            buffers,
1207            excerpts_by_path: Default::default(),
1208            paths_by_excerpt: Default::default(),
1209            diffs: diff_bases,
1210            subscriptions: Default::default(),
1211            singleton: self.singleton,
1212            capability: self.capability,
1213            history: self.history.clone(),
1214            title: self.title.clone(),
1215            buffer_changed_since_sync,
1216        }
1217    }
1218
1219    pub fn set_group_interval(&mut self, group_interval: Duration) {
1220        self.history.set_group_interval(group_interval);
1221    }
1222
1223    pub fn with_title(mut self, title: String) -> Self {
1224        self.title = Some(title);
1225        self
1226    }
1227
1228    pub fn read_only(&self) -> bool {
1229        !self.capability.editable()
1230    }
1231
1232    pub fn capability(&self) -> Capability {
1233        self.capability
1234    }
1235
1236    /// Returns an up-to-date snapshot of the MultiBuffer.
1237    #[ztracing::instrument(skip_all)]
1238    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1239        self.sync(cx);
1240        self.snapshot.borrow().clone()
1241    }
1242
1243    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1244        self.sync(cx);
1245        self.snapshot.borrow()
1246    }
1247
1248    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1249        if self.singleton {
1250            Some(self.buffers.values().next().unwrap().buffer.clone())
1251        } else {
1252            None
1253        }
1254    }
1255
1256    pub fn is_singleton(&self) -> bool {
1257        self.singleton
1258    }
1259
1260    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1261        self.subscriptions.subscribe()
1262    }
1263
1264    pub fn is_dirty(&self, cx: &App) -> bool {
1265        self.read(cx).is_dirty()
1266    }
1267
1268    pub fn has_deleted_file(&self, cx: &App) -> bool {
1269        self.read(cx).has_deleted_file()
1270    }
1271
1272    pub fn has_conflict(&self, cx: &App) -> bool {
1273        self.read(cx).has_conflict()
1274    }
1275
1276    // The `is_empty` signature doesn't match what clippy expects
1277    #[allow(clippy::len_without_is_empty)]
1278    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1279        self.read(cx).len()
1280    }
1281
1282    pub fn is_empty(&self) -> bool {
1283        self.buffers.is_empty()
1284    }
1285
1286    pub fn edit<I, S, T>(
1287        &mut self,
1288        edits: I,
1289        autoindent_mode: Option<AutoindentMode>,
1290        cx: &mut Context<Self>,
1291    ) where
1292        I: IntoIterator<Item = (Range<S>, T)>,
1293        S: ToOffset,
1294        T: Into<Arc<str>>,
1295    {
1296        self.edit_internal(edits, autoindent_mode, true, cx);
1297    }
1298
1299    pub fn edit_non_coalesce<I, S, T>(
1300        &mut self,
1301        edits: I,
1302        autoindent_mode: Option<AutoindentMode>,
1303        cx: &mut Context<Self>,
1304    ) where
1305        I: IntoIterator<Item = (Range<S>, T)>,
1306        S: ToOffset,
1307        T: Into<Arc<str>>,
1308    {
1309        self.edit_internal(edits, autoindent_mode, false, cx);
1310    }
1311
1312    fn edit_internal<I, S, T>(
1313        &mut self,
1314        edits: I,
1315        autoindent_mode: Option<AutoindentMode>,
1316        coalesce_adjacent: bool,
1317        cx: &mut Context<Self>,
1318    ) where
1319        I: IntoIterator<Item = (Range<S>, T)>,
1320        S: ToOffset,
1321        T: Into<Arc<str>>,
1322    {
1323        if self.read_only() || self.buffers.is_empty() {
1324            return;
1325        }
1326        self.sync_mut(cx);
1327        let edits = edits
1328            .into_iter()
1329            .map(|(range, new_text)| {
1330                let mut range = range.start.to_offset(self.snapshot.get_mut())
1331                    ..range.end.to_offset(self.snapshot.get_mut());
1332                if range.start > range.end {
1333                    mem::swap(&mut range.start, &mut range.end);
1334                }
1335                (range, new_text.into())
1336            })
1337            .collect::<Vec<_>>();
1338
1339        return edit_internal(self, edits, autoindent_mode, coalesce_adjacent, cx);
1340
1341        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1342        fn edit_internal(
1343            this: &mut MultiBuffer,
1344            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1345            mut autoindent_mode: Option<AutoindentMode>,
1346            coalesce_adjacent: bool,
1347            cx: &mut Context<MultiBuffer>,
1348        ) {
1349            let original_indent_columns = match &mut autoindent_mode {
1350                Some(AutoindentMode::Block {
1351                    original_indent_columns,
1352                }) => mem::take(original_indent_columns),
1353                _ => Default::default(),
1354            };
1355
1356            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1357                edits,
1358                this.snapshot.get_mut(),
1359                &original_indent_columns,
1360            );
1361
1362            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1363            for (buffer_id, mut edits) in buffer_edits {
1364                buffer_ids.push(buffer_id);
1365                edits.sort_by_key(|edit| edit.range.start);
1366                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1367                    let mut edits = edits.into_iter().peekable();
1368                    let mut insertions = Vec::new();
1369                    let mut original_indent_columns = Vec::new();
1370                    let mut deletions = Vec::new();
1371                    let empty_str: Arc<str> = Arc::default();
1372                    while let Some(BufferEdit {
1373                        mut range,
1374                        mut new_text,
1375                        mut is_insertion,
1376                        original_indent_column,
1377                        excerpt_id,
1378                    }) = edits.next()
1379                    {
1380                        while let Some(BufferEdit {
1381                            range: next_range,
1382                            is_insertion: next_is_insertion,
1383                            new_text: next_new_text,
1384                            excerpt_id: next_excerpt_id,
1385                            ..
1386                        }) = edits.peek()
1387                        {
1388                            let should_coalesce = if coalesce_adjacent {
1389                                range.end >= next_range.start
1390                            } else {
1391                                range.end > next_range.start
1392                            };
1393
1394                            if should_coalesce {
1395                                range.end = cmp::max(next_range.end, range.end);
1396                                is_insertion |= *next_is_insertion;
1397                                if excerpt_id == *next_excerpt_id {
1398                                    new_text = format!("{new_text}{next_new_text}").into();
1399                                }
1400                                edits.next();
1401                            } else {
1402                                break;
1403                            }
1404                        }
1405
1406                        if is_insertion {
1407                            original_indent_columns.push(original_indent_column);
1408                            insertions.push((
1409                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1410                                new_text.clone(),
1411                            ));
1412                        } else if !range.is_empty() {
1413                            deletions.push((
1414                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1415                                empty_str.clone(),
1416                            ));
1417                        }
1418                    }
1419
1420                    let deletion_autoindent_mode =
1421                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1422                            Some(AutoindentMode::Block {
1423                                original_indent_columns: Default::default(),
1424                            })
1425                        } else {
1426                            autoindent_mode.clone()
1427                        };
1428                    let insertion_autoindent_mode =
1429                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1430                            Some(AutoindentMode::Block {
1431                                original_indent_columns,
1432                            })
1433                        } else {
1434                            autoindent_mode.clone()
1435                        };
1436
1437                    if coalesce_adjacent {
1438                        buffer.edit(deletions, deletion_autoindent_mode, cx);
1439                        buffer.edit(insertions, insertion_autoindent_mode, cx);
1440                    } else {
1441                        buffer.edit_non_coalesce(deletions, deletion_autoindent_mode, cx);
1442                        buffer.edit_non_coalesce(insertions, insertion_autoindent_mode, cx);
1443                    }
1444                })
1445            }
1446
1447            cx.emit(Event::ExcerptsEdited {
1448                excerpt_ids: edited_excerpt_ids,
1449                buffer_ids,
1450            });
1451        }
1452    }
1453
1454    fn convert_edits_to_buffer_edits(
1455        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1456        snapshot: &MultiBufferSnapshot,
1457        original_indent_columns: &[Option<u32>],
1458    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1459        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1460        let mut edited_excerpt_ids = Vec::new();
1461        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1462        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1463            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1464
1465            cursor.seek(&range.start);
1466            let mut start_region = cursor.region().expect("start offset out of bounds");
1467            if !start_region.is_main_buffer {
1468                cursor.next();
1469                if let Some(region) = cursor.region() {
1470                    start_region = region;
1471                } else {
1472                    continue;
1473                }
1474            }
1475
1476            if range.end < start_region.range.start {
1477                continue;
1478            }
1479
1480            let start_region = start_region.clone();
1481            if range.end > start_region.range.end {
1482                cursor.seek_forward(&range.end);
1483            }
1484            let mut end_region = cursor.region().expect("end offset out of bounds");
1485            if !end_region.is_main_buffer {
1486                cursor.prev();
1487                if let Some(region) = cursor.region() {
1488                    end_region = region;
1489                } else {
1490                    continue;
1491                }
1492            }
1493
1494            if range.start > end_region.range.end {
1495                continue;
1496            }
1497
1498            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1499            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1500            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1501                .min(start_region.buffer_range.end);
1502            let buffer_end =
1503                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1504
1505            if start_region.excerpt.id == end_region.excerpt.id {
1506                if start_region.buffer.capability == Capability::ReadWrite
1507                    && start_region.is_main_buffer
1508                {
1509                    edited_excerpt_ids.push(start_region.excerpt.id);
1510                    buffer_edits
1511                        .entry(start_region.buffer.remote_id())
1512                        .or_default()
1513                        .push(BufferEdit {
1514                            range: buffer_start..buffer_end,
1515                            new_text,
1516                            is_insertion: true,
1517                            original_indent_column,
1518                            excerpt_id: start_region.excerpt.id,
1519                        });
1520                }
1521            } else {
1522                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1523                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1524                if start_region.buffer.capability == Capability::ReadWrite
1525                    && start_region.is_main_buffer
1526                {
1527                    edited_excerpt_ids.push(start_region.excerpt.id);
1528                    buffer_edits
1529                        .entry(start_region.buffer.remote_id())
1530                        .or_default()
1531                        .push(BufferEdit {
1532                            range: start_excerpt_range,
1533                            new_text: new_text.clone(),
1534                            is_insertion: true,
1535                            original_indent_column,
1536                            excerpt_id: start_region.excerpt.id,
1537                        });
1538                }
1539                let excerpt_id = end_region.excerpt.id;
1540                if end_region.buffer.capability == Capability::ReadWrite
1541                    && end_region.is_main_buffer
1542                {
1543                    edited_excerpt_ids.push(excerpt_id);
1544                    buffer_edits
1545                        .entry(end_region.buffer.remote_id())
1546                        .or_default()
1547                        .push(BufferEdit {
1548                            range: end_excerpt_range,
1549                            new_text: new_text.clone(),
1550                            is_insertion: false,
1551                            original_indent_column,
1552                            excerpt_id,
1553                        });
1554                }
1555
1556                cursor.seek(&range.start);
1557                cursor.next_excerpt();
1558                while let Some(region) = cursor.region() {
1559                    if region.excerpt.id == excerpt_id {
1560                        break;
1561                    }
1562                    if region.buffer.capability == Capability::ReadWrite && region.is_main_buffer {
1563                        edited_excerpt_ids.push(region.excerpt.id);
1564                        buffer_edits
1565                            .entry(region.buffer.remote_id())
1566                            .or_default()
1567                            .push(BufferEdit {
1568                                range: region.buffer_range.clone(),
1569                                new_text: new_text.clone(),
1570                                is_insertion: false,
1571                                original_indent_column,
1572                                excerpt_id: region.excerpt.id,
1573                            });
1574                    }
1575                    cursor.next_excerpt();
1576                }
1577            }
1578        }
1579        (buffer_edits, edited_excerpt_ids)
1580    }
1581
1582    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1583    where
1584        I: IntoIterator<Item = Range<S>>,
1585        S: ToOffset,
1586    {
1587        if self.read_only() || self.buffers.is_empty() {
1588            return;
1589        }
1590        self.sync_mut(cx);
1591        let empty = Arc::<str>::from("");
1592        let edits = ranges
1593            .into_iter()
1594            .map(|range| {
1595                let mut range = range.start.to_offset(self.snapshot.get_mut())
1596                    ..range.end.to_offset(&self.snapshot.get_mut());
1597                if range.start > range.end {
1598                    mem::swap(&mut range.start, &mut range.end);
1599                }
1600                (range, empty.clone())
1601            })
1602            .collect::<Vec<_>>();
1603
1604        return autoindent_ranges_internal(self, edits, cx);
1605
1606        fn autoindent_ranges_internal(
1607            this: &mut MultiBuffer,
1608            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1609            cx: &mut Context<MultiBuffer>,
1610        ) {
1611            let (buffer_edits, edited_excerpt_ids) =
1612                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1613
1614            let mut buffer_ids = Vec::new();
1615            for (buffer_id, mut edits) in buffer_edits {
1616                buffer_ids.push(buffer_id);
1617                edits.sort_unstable_by_key(|edit| edit.range.start);
1618
1619                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1620                for edit in edits {
1621                    if let Some(last_range) = ranges.last_mut()
1622                        && edit.range.start <= last_range.end
1623                    {
1624                        last_range.end = last_range.end.max(edit.range.end);
1625                        continue;
1626                    }
1627                    ranges.push(edit.range);
1628                }
1629
1630                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1631                    buffer.autoindent_ranges(ranges, cx);
1632                })
1633            }
1634
1635            cx.emit(Event::ExcerptsEdited {
1636                excerpt_ids: edited_excerpt_ids,
1637                buffer_ids,
1638            });
1639        }
1640    }
1641
1642    pub fn set_active_selections(
1643        &self,
1644        selections: &[Selection<Anchor>],
1645        line_mode: bool,
1646        cursor_shape: CursorShape,
1647        cx: &mut Context<Self>,
1648    ) {
1649        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1650            Default::default();
1651        let snapshot = self.read(cx);
1652        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1653        for selection in selections {
1654            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1655            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1656
1657            cursor.seek(&Some(start_locator), Bias::Left);
1658            while let Some(excerpt) = cursor.item()
1659                && excerpt.locator <= *end_locator
1660            {
1661                let mut start = excerpt.range.context.start;
1662                let mut end = excerpt.range.context.end;
1663                if excerpt.id == selection.start.excerpt_id {
1664                    start = selection.start.text_anchor;
1665                }
1666                if excerpt.id == selection.end.excerpt_id {
1667                    end = selection.end.text_anchor;
1668                }
1669                selections_by_buffer
1670                    .entry(excerpt.buffer_id)
1671                    .or_default()
1672                    .push(Selection {
1673                        id: selection.id,
1674                        start,
1675                        end,
1676                        reversed: selection.reversed,
1677                        goal: selection.goal,
1678                    });
1679
1680                cursor.next();
1681            }
1682        }
1683
1684        for (buffer_id, buffer_state) in self.buffers.iter() {
1685            if !selections_by_buffer.contains_key(buffer_id) {
1686                buffer_state
1687                    .buffer
1688                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1689            }
1690        }
1691
1692        for (buffer_id, mut selections) in selections_by_buffer {
1693            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1694                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1695                let mut selections = selections.into_iter().peekable();
1696                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1697                    let mut selection = selections.next()?;
1698                    while let Some(next_selection) = selections.peek() {
1699                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1700                            let next_selection = selections.next().unwrap();
1701                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1702                                selection.end = next_selection.end;
1703                            }
1704                        } else {
1705                            break;
1706                        }
1707                    }
1708                    Some(selection)
1709                }));
1710                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1711            });
1712        }
1713    }
1714
1715    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1716        for buffer in self.buffers.values() {
1717            buffer
1718                .buffer
1719                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1720        }
1721    }
1722
1723    pub fn push_excerpts<O>(
1724        &mut self,
1725        buffer: Entity<Buffer>,
1726        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1727        cx: &mut Context<Self>,
1728    ) -> Vec<ExcerptId>
1729    where
1730        O: text::ToOffset,
1731    {
1732        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1733    }
1734
1735    #[instrument(skip_all)]
1736    fn merge_excerpt_ranges<'a>(
1737        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1738    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1739        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1740        let mut counts: Vec<usize> = Vec::new();
1741        for range in expanded_ranges {
1742            if let Some(last_range) = merged_ranges.last_mut() {
1743                assert!(
1744                    last_range.context.start <= range.context.start,
1745                    "ranges must be sorted: {last_range:?} <= {range:?}"
1746                );
1747                if last_range.context.end >= range.context.start
1748                    || last_range.context.end.row + 1 == range.context.start.row
1749                {
1750                    last_range.context.end = range.context.end.max(last_range.context.end);
1751                    *counts.last_mut().unwrap() += 1;
1752                    continue;
1753                }
1754            }
1755            merged_ranges.push(range.clone());
1756            counts.push(1);
1757        }
1758        (merged_ranges, counts)
1759    }
1760
1761    pub fn insert_excerpts_after<O>(
1762        &mut self,
1763        prev_excerpt_id: ExcerptId,
1764        buffer: Entity<Buffer>,
1765        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1766        cx: &mut Context<Self>,
1767    ) -> Vec<ExcerptId>
1768    where
1769        O: text::ToOffset,
1770    {
1771        let mut ids = Vec::new();
1772        let mut next_excerpt_id =
1773            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1774                last_entry.id.0 + 1
1775            } else {
1776                1
1777            };
1778        self.insert_excerpts_with_ids_after(
1779            prev_excerpt_id,
1780            buffer,
1781            ranges.into_iter().map(|range| {
1782                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1783                ids.push(id);
1784                (id, range)
1785            }),
1786            cx,
1787        );
1788        ids
1789    }
1790
1791    pub fn insert_excerpts_with_ids_after<O>(
1792        &mut self,
1793        prev_excerpt_id: ExcerptId,
1794        buffer: Entity<Buffer>,
1795        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1796        cx: &mut Context<Self>,
1797    ) where
1798        O: text::ToOffset,
1799    {
1800        assert_eq!(self.history.transaction_depth(), 0);
1801        let mut ranges = ranges.into_iter().peekable();
1802        if ranges.peek().is_none() {
1803            return Default::default();
1804        }
1805
1806        self.sync_mut(cx);
1807
1808        let buffer_snapshot = buffer.read(cx).snapshot();
1809        let buffer_id = buffer_snapshot.remote_id();
1810
1811        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1812            self.buffer_changed_since_sync.replace(true);
1813            buffer.update(cx, |buffer, _| {
1814                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1815            });
1816            BufferState {
1817                last_version: RefCell::new(buffer_snapshot.version().clone()),
1818                last_non_text_state_update_count: Cell::new(
1819                    buffer_snapshot.non_text_state_update_count(),
1820                ),
1821                excerpts: Default::default(),
1822                _subscriptions: [
1823                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1824                    cx.subscribe(&buffer, Self::on_buffer_event),
1825                ],
1826                buffer: buffer.clone(),
1827            }
1828        });
1829
1830        let mut snapshot = self.snapshot.get_mut();
1831
1832        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1833        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1834        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1835        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1836        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1837
1838        let edit_start = ExcerptDimension(new_excerpts.summary().text.len);
1839        new_excerpts.update_last(
1840            |excerpt| {
1841                excerpt.has_trailing_newline = true;
1842            },
1843            (),
1844        );
1845
1846        let next_locator = if let Some(excerpt) = cursor.item() {
1847            excerpt.locator.clone()
1848        } else {
1849            Locator::max()
1850        };
1851
1852        let mut excerpts = Vec::new();
1853        let buffer_snapshot = Arc::new(buffer_snapshot);
1854        while let Some((id, range)) = ranges.next() {
1855            let locator = Locator::between(&prev_locator, &next_locator);
1856            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1857                buffer_state.excerpts.insert(ix, locator.clone());
1858            }
1859            let range = ExcerptRange {
1860                context: buffer_snapshot.anchor_before(&range.context.start)
1861                    ..buffer_snapshot.anchor_after(&range.context.end),
1862                primary: buffer_snapshot.anchor_before(&range.primary.start)
1863                    ..buffer_snapshot.anchor_after(&range.primary.end),
1864            };
1865            excerpts.push((id, range.clone()));
1866            let excerpt = Excerpt::new(
1867                id,
1868                locator.clone(),
1869                buffer_id,
1870                buffer_snapshot.clone(),
1871                range,
1872                ranges.peek().is_some() || cursor.item().is_some(),
1873            );
1874            new_excerpts.push(excerpt, ());
1875            prev_locator = locator.clone();
1876
1877            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1878                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1879            }
1880            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1881        }
1882        snapshot
1883            .buffer_locators
1884            .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
1885
1886        let edit_end = ExcerptDimension(new_excerpts.summary().text.len);
1887
1888        let suffix = cursor.suffix();
1889        let changed_trailing_excerpt = suffix.is_empty();
1890        new_excerpts.append(suffix, ());
1891        drop(cursor);
1892        snapshot.excerpts = new_excerpts;
1893        snapshot.excerpt_ids = new_excerpt_ids;
1894        if changed_trailing_excerpt {
1895            snapshot.trailing_excerpt_update_count += 1;
1896        }
1897
1898        let edits = Self::sync_diff_transforms(
1899            &mut snapshot,
1900            vec![Edit {
1901                old: edit_start..edit_start,
1902                new: edit_start..edit_end,
1903            }],
1904            DiffChangeKind::BufferEdited,
1905        );
1906        if !edits.is_empty() {
1907            self.subscriptions.publish(edits);
1908        }
1909
1910        cx.emit(Event::Edited {
1911            edited_buffer: None,
1912        });
1913        cx.emit(Event::ExcerptsAdded {
1914            buffer,
1915            predecessor: prev_excerpt_id,
1916            excerpts,
1917        });
1918        cx.notify();
1919    }
1920
1921    pub fn clear(&mut self, cx: &mut Context<Self>) {
1922        self.sync_mut(cx);
1923        let ids = self.excerpt_ids();
1924        let removed_buffer_ids = std::mem::take(&mut self.buffers).into_keys().collect();
1925        self.excerpts_by_path.clear();
1926        self.paths_by_excerpt.clear();
1927        let MultiBufferSnapshot {
1928            excerpts,
1929            buffer_locators,
1930            diffs: _,
1931            diff_transforms: _,
1932            non_text_state_update_count: _,
1933            edit_count: _,
1934            is_dirty,
1935            has_deleted_file,
1936            has_conflict,
1937            has_inverted_diff,
1938            singleton: _,
1939            excerpt_ids: _,
1940            replaced_excerpts,
1941            trailing_excerpt_update_count,
1942            all_diff_hunks_expanded: _,
1943            show_deleted_hunks: _,
1944            use_extended_diff_range: _,
1945            show_headers: _,
1946        } = self.snapshot.get_mut();
1947        buffer_locators.clear();
1948        let start = ExcerptDimension(MultiBufferOffset::ZERO);
1949        let prev_len = ExcerptDimension(excerpts.summary().text.len);
1950        *excerpts = Default::default();
1951        *trailing_excerpt_update_count += 1;
1952        *is_dirty = false;
1953        *has_deleted_file = false;
1954        *has_conflict = false;
1955        *has_inverted_diff = false;
1956        replaced_excerpts.clear();
1957
1958        let edits = Self::sync_diff_transforms(
1959            self.snapshot.get_mut(),
1960            vec![Edit {
1961                old: start..prev_len,
1962                new: start..start,
1963            }],
1964            DiffChangeKind::BufferEdited,
1965        );
1966        if !edits.is_empty() {
1967            self.subscriptions.publish(edits);
1968        }
1969        cx.emit(Event::Edited {
1970            edited_buffer: None,
1971        });
1972        cx.emit(Event::ExcerptsRemoved {
1973            ids,
1974            removed_buffer_ids,
1975        });
1976        cx.notify();
1977    }
1978
1979    #[ztracing::instrument(skip_all)]
1980    pub fn excerpts_for_buffer(
1981        &self,
1982        buffer_id: BufferId,
1983        cx: &App,
1984    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1985        let mut excerpts = Vec::new();
1986        let snapshot = self.read(cx);
1987        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1988        if let Some(locators) = snapshot.buffer_locators.get(&buffer_id) {
1989            for locator in &**locators {
1990                cursor.seek_forward(&Some(locator), Bias::Left);
1991                if let Some(excerpt) = cursor.item()
1992                    && excerpt.locator == *locator
1993                {
1994                    excerpts.push((excerpt.id, excerpt.range.clone()));
1995                }
1996            }
1997        }
1998
1999        excerpts
2000    }
2001
2002    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2003        let snapshot = self.read(cx);
2004        let mut excerpts = snapshot
2005            .excerpts
2006            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
2007        let mut diff_transforms = snapshot
2008            .diff_transforms
2009            .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
2010        diff_transforms.next();
2011        let locators = snapshot
2012            .buffer_locators
2013            .get(&buffer_id)
2014            .into_iter()
2015            .flat_map(|v| &**v);
2016        let mut result = Vec::new();
2017        for locator in locators {
2018            excerpts.seek_forward(&Some(locator), Bias::Left);
2019            if let Some(excerpt) = excerpts.item()
2020                && excerpt.locator == *locator
2021            {
2022                let excerpt_start = excerpts.start().1;
2023                let excerpt_end = excerpt_start + excerpt.text_summary.lines;
2024
2025                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2026                let overshoot = excerpt_start - diff_transforms.start().0;
2027                let start = diff_transforms.start().1 + overshoot;
2028
2029                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2030                let overshoot = excerpt_end - diff_transforms.start().0;
2031                let end = diff_transforms.start().1 + overshoot;
2032
2033                result.push(start.0..end.0)
2034            }
2035        }
2036        result
2037    }
2038
2039    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2040        self.snapshot
2041            .borrow()
2042            .excerpts
2043            .iter()
2044            .map(|entry| entry.buffer_id)
2045            .collect()
2046    }
2047
2048    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2049        self.snapshot
2050            .borrow()
2051            .excerpts
2052            .iter()
2053            .map(|entry| entry.id)
2054            .collect()
2055    }
2056
2057    pub fn excerpt_containing(
2058        &self,
2059        position: impl ToOffset,
2060        cx: &App,
2061    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2062        let snapshot = self.read(cx);
2063        let offset = position.to_offset(&snapshot);
2064
2065        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
2066        cursor.seek(&offset);
2067        cursor
2068            .excerpt()
2069            .or_else(|| snapshot.excerpts.last())
2070            .map(|excerpt| {
2071                (
2072                    excerpt.id,
2073                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
2074                    excerpt.range.context.clone(),
2075                )
2076            })
2077    }
2078
2079    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2080        if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2081            self.buffer(buffer_id)
2082        } else {
2083            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2084            Some(buffer)
2085        }
2086    }
2087
2088    // If point is at the end of the buffer, the last excerpt is returned
2089    pub fn point_to_buffer_offset<T: ToOffset>(
2090        &self,
2091        point: T,
2092        cx: &App,
2093    ) -> Option<(Entity<Buffer>, BufferOffset)> {
2094        let snapshot = self.read(cx);
2095        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2096        Some((
2097            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2098            offset,
2099        ))
2100    }
2101
2102    // If point is at the end of the buffer, the last excerpt is returned
2103    pub fn point_to_buffer_point<T: ToPoint>(
2104        &self,
2105        point: T,
2106        cx: &App,
2107    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2108        let snapshot = self.read(cx);
2109        let (buffer, point, is_main_buffer) =
2110            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2111        Some((
2112            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
2113            point,
2114            is_main_buffer,
2115        ))
2116    }
2117
2118    pub fn buffer_point_to_anchor(
2119        &self,
2120        // todo(lw): We shouldn't need this?
2121        buffer: &Entity<Buffer>,
2122        point: Point,
2123        cx: &App,
2124    ) -> Option<Anchor> {
2125        let mut found = None;
2126        let snapshot = buffer.read(cx).snapshot();
2127        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2128            let start = range.context.start.to_point(&snapshot);
2129            let end = range.context.end.to_point(&snapshot);
2130            if start <= point && point < end {
2131                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2132                break;
2133            }
2134            if point < start {
2135                found = Some((start, excerpt_id));
2136            }
2137            if point > end {
2138                found = Some((end, excerpt_id));
2139            }
2140        }
2141
2142        found.map(|(point, excerpt_id)| {
2143            let text_anchor = snapshot.anchor_after(point);
2144            Anchor::in_buffer(excerpt_id, text_anchor)
2145        })
2146    }
2147
2148    pub fn buffer_anchor_to_anchor(
2149        &self,
2150        // todo(lw): We shouldn't need this?
2151        buffer: &Entity<Buffer>,
2152        anchor: text::Anchor,
2153        cx: &App,
2154    ) -> Option<Anchor> {
2155        let snapshot = buffer.read(cx).snapshot();
2156        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2157            if range.context.start.cmp(&anchor, &snapshot).is_le()
2158                && range.context.end.cmp(&anchor, &snapshot).is_ge()
2159            {
2160                return Some(Anchor::in_buffer(excerpt_id, anchor));
2161            }
2162        }
2163
2164        None
2165    }
2166
2167    pub fn remove_excerpts(
2168        &mut self,
2169        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2170        cx: &mut Context<Self>,
2171    ) {
2172        self.sync_mut(cx);
2173        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2174        if ids.is_empty() {
2175            return;
2176        }
2177        self.buffer_changed_since_sync.replace(true);
2178
2179        let mut snapshot = self.snapshot.get_mut();
2180        let mut new_excerpts = SumTree::default();
2181        let mut cursor = snapshot
2182            .excerpts
2183            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2184        let mut edits = Vec::new();
2185        let mut excerpt_ids = ids.iter().copied().peekable();
2186        let mut removed_buffer_ids = Vec::new();
2187        let mut removed_excerpts_for_buffers = HashSet::default();
2188
2189        while let Some(excerpt_id) = excerpt_ids.next() {
2190            self.paths_by_excerpt.remove(&excerpt_id);
2191            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2192            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2193            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2194
2195            if let Some(mut excerpt) = cursor.item() {
2196                if excerpt.id != excerpt_id {
2197                    continue;
2198                }
2199                let mut old_start = cursor.start().1;
2200
2201                // Skip over the removed excerpt.
2202                'remove_excerpts: loop {
2203                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2204                        removed_excerpts_for_buffers.insert(excerpt.buffer_id);
2205                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2206                        if buffer_state.excerpts.is_empty() {
2207                            log::debug!(
2208                                "removing buffer and diff for buffer {}",
2209                                excerpt.buffer_id
2210                            );
2211                            self.buffers.remove(&excerpt.buffer_id);
2212                            removed_buffer_ids.push(excerpt.buffer_id);
2213                        }
2214                    }
2215                    cursor.next();
2216
2217                    // Skip over any subsequent excerpts that are also removed.
2218                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2219                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2220                        if let Some(next_excerpt) = cursor.item()
2221                            && next_excerpt.locator == *next_locator
2222                        {
2223                            excerpt_ids.next();
2224                            excerpt = next_excerpt;
2225                            continue 'remove_excerpts;
2226                        }
2227                    }
2228
2229                    break;
2230                }
2231
2232                // When removing the last excerpt, remove the trailing newline from
2233                // the previous excerpt.
2234                if cursor.item().is_none() && old_start > MultiBufferOffset::ZERO {
2235                    old_start -= 1;
2236                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2237                }
2238
2239                // Push an edit for the removal of this run of excerpts.
2240                let old_end = cursor.start().1;
2241                let new_start = ExcerptDimension(new_excerpts.summary().text.len);
2242                edits.push(Edit {
2243                    old: old_start..old_end,
2244                    new: new_start..new_start,
2245                });
2246            }
2247        }
2248        let suffix = cursor.suffix();
2249        let changed_trailing_excerpt = suffix.is_empty();
2250        new_excerpts.append(suffix, ());
2251        drop(cursor);
2252        for buffer_id in removed_excerpts_for_buffers {
2253            match self.buffers.get(&buffer_id) {
2254                Some(buffer_state) => {
2255                    snapshot
2256                        .buffer_locators
2257                        .insert(buffer_id, buffer_state.excerpts.iter().cloned().collect());
2258                }
2259                None => {
2260                    snapshot.buffer_locators.remove(&buffer_id);
2261                }
2262            }
2263        }
2264        snapshot.excerpts = new_excerpts;
2265        for buffer_id in &removed_buffer_ids {
2266            self.diffs.remove(buffer_id);
2267            snapshot.diffs.remove(buffer_id);
2268        }
2269
2270        // Recalculate has_inverted_diff after removing diffs
2271        if !removed_buffer_ids.is_empty() {
2272            snapshot.has_inverted_diff = snapshot.diffs.iter().any(|(_, diff)| diff.is_inverted);
2273        }
2274
2275        if changed_trailing_excerpt {
2276            snapshot.trailing_excerpt_update_count += 1;
2277        }
2278
2279        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2280        if !edits.is_empty() {
2281            self.subscriptions.publish(edits);
2282        }
2283        cx.emit(Event::Edited {
2284            edited_buffer: None,
2285        });
2286        cx.emit(Event::ExcerptsRemoved {
2287            ids,
2288            removed_buffer_ids,
2289        });
2290        cx.notify();
2291    }
2292
2293    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2294        &self,
2295        anchors: Anchors,
2296        cx: &mut Context<Self>,
2297    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2298        let mut error = None;
2299        let mut futures = Vec::new();
2300        for anchor in anchors {
2301            if let Some(buffer_id) = anchor.text_anchor.buffer_id {
2302                if let Some(buffer) = self.buffers.get(&buffer_id) {
2303                    buffer.buffer.update(cx, |buffer, _| {
2304                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2305                    });
2306                } else {
2307                    error = Some(anyhow!(
2308                        "buffer {buffer_id} is not part of this multi-buffer"
2309                    ));
2310                    break;
2311                }
2312            }
2313        }
2314        async move {
2315            if let Some(error) = error {
2316                Err(error)?;
2317            }
2318            for future in futures {
2319                future.await?;
2320            }
2321            Ok(())
2322        }
2323    }
2324
2325    pub fn text_anchor_for_position<T: ToOffset>(
2326        &self,
2327        position: T,
2328        cx: &App,
2329    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2330        let snapshot = self.read(cx);
2331        let anchor = snapshot.anchor_before(position);
2332        let buffer = self
2333            .buffers
2334            .get(&anchor.text_anchor.buffer_id?)?
2335            .buffer
2336            .clone();
2337        Some((buffer, anchor.text_anchor))
2338    }
2339
2340    fn on_buffer_event(
2341        &mut self,
2342        buffer: Entity<Buffer>,
2343        event: &language::BufferEvent,
2344        cx: &mut Context<Self>,
2345    ) {
2346        use language::BufferEvent;
2347        let buffer_id = buffer.read(cx).remote_id();
2348        cx.emit(match event {
2349            BufferEvent::Edited => Event::Edited {
2350                edited_buffer: Some(buffer),
2351            },
2352            BufferEvent::DirtyChanged => Event::DirtyChanged,
2353            BufferEvent::Saved => Event::Saved,
2354            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2355            BufferEvent::Reloaded => Event::Reloaded,
2356            BufferEvent::LanguageChanged(has_language) => {
2357                Event::LanguageChanged(buffer_id, *has_language)
2358            }
2359            BufferEvent::Reparsed => Event::Reparsed(buffer_id),
2360            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2361            BufferEvent::CapabilityChanged => {
2362                self.capability = buffer.read(cx).capability();
2363                return;
2364            }
2365            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2366        });
2367    }
2368
2369    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2370        let diff = diff.read(cx);
2371        let buffer_id = diff.buffer_id;
2372        let diff = DiffStateSnapshot {
2373            diff: diff.snapshot(cx),
2374            is_inverted: false,
2375        };
2376        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2377    }
2378
2379    fn inverted_buffer_diff_language_changed(
2380        &mut self,
2381        diff: Entity<BufferDiff>,
2382        cx: &mut Context<Self>,
2383    ) {
2384        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2385        let diff = diff.read(cx);
2386        let diff = DiffStateSnapshot {
2387            diff: diff.snapshot(cx),
2388            is_inverted: true,
2389        };
2390        self.snapshot
2391            .get_mut()
2392            .diffs
2393            .insert(base_text_buffer_id, diff);
2394    }
2395
2396    fn buffer_diff_changed(
2397        &mut self,
2398        diff: Entity<BufferDiff>,
2399        range: Range<text::Anchor>,
2400        cx: &mut Context<Self>,
2401    ) {
2402        self.sync_mut(cx);
2403
2404        let diff = diff.read(cx);
2405        let buffer_id = diff.buffer_id;
2406
2407        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2408            return;
2409        };
2410        let new_diff = DiffStateSnapshot {
2411            diff: diff.snapshot(cx),
2412            is_inverted: false,
2413        };
2414        let mut snapshot = self.snapshot.get_mut();
2415        let base_text_changed = snapshot
2416            .diffs
2417            .get(&buffer_id)
2418            .is_none_or(|old_diff| !new_diff.base_texts_definitely_eq(old_diff));
2419        snapshot.diffs.insert_or_replace(buffer_id, new_diff);
2420
2421        let buffer = buffer_state.buffer.read(cx);
2422        let diff_change_range = range.to_offset(buffer);
2423
2424        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2425        let edits = Self::sync_diff_transforms(
2426            &mut snapshot,
2427            excerpt_edits,
2428            DiffChangeKind::DiffUpdated {
2429                base_changed: base_text_changed,
2430            },
2431        );
2432        if !edits.is_empty() {
2433            self.subscriptions.publish(edits);
2434        }
2435        cx.emit(Event::Edited {
2436            edited_buffer: None,
2437        });
2438    }
2439
2440    fn inverted_buffer_diff_changed(
2441        &mut self,
2442        diff: Entity<BufferDiff>,
2443        diff_change_range: Range<usize>,
2444        cx: &mut Context<Self>,
2445    ) {
2446        self.sync_mut(cx);
2447
2448        let diff = diff.read(cx);
2449        let base_text_buffer_id = diff.base_text(cx).remote_id();
2450        let Some(buffer_state) = self.buffers.get(&base_text_buffer_id) else {
2451            return;
2452        };
2453
2454        let new_diff = DiffStateSnapshot {
2455            diff: diff.snapshot(cx),
2456            is_inverted: true,
2457        };
2458        let mut snapshot = self.snapshot.get_mut();
2459        snapshot
2460            .diffs
2461            .insert_or_replace(base_text_buffer_id, new_diff);
2462
2463        let excerpt_edits = snapshot.excerpt_edits_for_diff_change(buffer_state, diff_change_range);
2464        let edits = Self::sync_diff_transforms(
2465            &mut snapshot,
2466            excerpt_edits,
2467            DiffChangeKind::DiffUpdated {
2468                // We don't read this field for inverted diffs.
2469                base_changed: false,
2470            },
2471        );
2472        if !edits.is_empty() {
2473            self.subscriptions.publish(edits);
2474        }
2475        cx.emit(Event::Edited {
2476            edited_buffer: None,
2477        });
2478    }
2479
2480    pub fn all_buffers_iter(&self) -> impl Iterator<Item = Entity<Buffer>> {
2481        self.buffers.values().map(|state| state.buffer.clone())
2482    }
2483
2484    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2485        self.all_buffers_iter().collect()
2486    }
2487
2488    pub fn all_buffer_ids_iter(&self) -> impl Iterator<Item = BufferId> {
2489        self.buffers.keys().copied()
2490    }
2491
2492    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2493        self.all_buffer_ids_iter().collect()
2494    }
2495
2496    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2497        self.buffers
2498            .get(&buffer_id)
2499            .map(|state| state.buffer.clone())
2500    }
2501
2502    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2503        self.point_to_buffer_offset(point, cx)
2504            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2505    }
2506
2507    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2508        let buffer_id = self
2509            .snapshot
2510            .borrow()
2511            .excerpts
2512            .first()
2513            .map(|excerpt| excerpt.buffer.remote_id());
2514        buffer_id
2515            .and_then(|buffer_id| self.buffer(buffer_id))
2516            .map(|buffer| {
2517                let buffer = buffer.read(cx);
2518                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2519            })
2520            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2521    }
2522
2523    pub fn language_settings_at<'a, T: ToOffset>(
2524        &'a self,
2525        point: T,
2526        cx: &'a App,
2527    ) -> Cow<'a, LanguageSettings> {
2528        let mut language = None;
2529        let mut file = None;
2530        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2531            let buffer = buffer.read(cx);
2532            language = buffer.language_at(offset);
2533            file = buffer.file();
2534        }
2535        language_settings(language.map(|l| l.name()), file, cx)
2536    }
2537
2538    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2539        self.buffers.values().for_each(|state| f(&state.buffer))
2540    }
2541
2542    pub fn explicit_title(&self) -> Option<&str> {
2543        self.title.as_deref()
2544    }
2545
2546    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2547        if let Some(title) = self.title.as_ref() {
2548            return title.into();
2549        }
2550
2551        if let Some(buffer) = self.as_singleton() {
2552            let buffer = buffer.read(cx);
2553
2554            if let Some(file) = buffer.file() {
2555                return file.file_name(cx).into();
2556            }
2557
2558            if let Some(title) = self.buffer_content_title(buffer) {
2559                return title;
2560            }
2561        };
2562
2563        "untitled".into()
2564    }
2565
2566    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2567        let mut is_leading_whitespace = true;
2568        let mut count = 0;
2569        let mut prev_was_space = false;
2570        let mut title = String::new();
2571
2572        for ch in buffer.snapshot().chars() {
2573            if is_leading_whitespace && ch.is_whitespace() {
2574                continue;
2575            }
2576
2577            is_leading_whitespace = false;
2578
2579            if ch == '\n' || count >= 40 {
2580                break;
2581            }
2582
2583            if ch.is_whitespace() {
2584                if !prev_was_space {
2585                    title.push(' ');
2586                    count += 1;
2587                    prev_was_space = true;
2588                }
2589            } else {
2590                title.push(ch);
2591                count += 1;
2592                prev_was_space = false;
2593            }
2594        }
2595
2596        let title = title.trim_end().to_string();
2597
2598        if title.is_empty() {
2599            return None;
2600        }
2601
2602        Some(title.into())
2603    }
2604
2605    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2606        self.title = Some(title);
2607        cx.notify();
2608    }
2609
2610    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2611    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2612        for buffer_state in self.buffers.values() {
2613            buffer_state
2614                .buffer
2615                .update(cx, |buffer, _cx| buffer.refresh_preview());
2616        }
2617    }
2618
2619    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2620    pub fn preserve_preview(&self, cx: &App) -> bool {
2621        self.buffers
2622            .values()
2623            .all(|state| state.buffer.read(cx).preserve_preview())
2624    }
2625
2626    #[cfg(any(test, feature = "test-support"))]
2627    pub fn is_parsing(&self, cx: &App) -> bool {
2628        self.as_singleton().unwrap().read(cx).is_parsing()
2629    }
2630
2631    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2632        let buffer_id = diff.read(cx).buffer_id;
2633
2634        if let Some(existing_diff) = self.diff_for(buffer_id)
2635            && diff.entity_id() == existing_diff.entity_id()
2636        {
2637            return;
2638        }
2639
2640        self.buffer_diff_changed(
2641            diff.clone(),
2642            text::Anchor::min_max_range_for_buffer(buffer_id),
2643            cx,
2644        );
2645        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2646    }
2647
2648    pub fn add_inverted_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2649        let base_text_buffer_id = diff.read(cx).base_text(cx).remote_id();
2650        let diff_change_range = 0..diff.read(cx).base_text(cx).len();
2651        self.snapshot.get_mut().has_inverted_diff = true;
2652        self.inverted_buffer_diff_changed(diff.clone(), diff_change_range, cx);
2653        self.diffs
2654            .insert(base_text_buffer_id, DiffState::new_inverted(diff, cx));
2655    }
2656
2657    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2658        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2659    }
2660
2661    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2662        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2663    }
2664
2665    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2666        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2667    }
2668
2669    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2670        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2671        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2672    }
2673
2674    pub fn all_diff_hunks_expanded(&self) -> bool {
2675        self.snapshot.borrow().all_diff_hunks_expanded
2676    }
2677
2678    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2679        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2680        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2681    }
2682
2683    pub fn set_show_deleted_hunks(&mut self, show: bool, cx: &mut Context<Self>) {
2684        self.snapshot.get_mut().show_deleted_hunks = show;
2685        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2686    }
2687
2688    pub fn set_use_extended_diff_range(&mut self, use_extended: bool, _cx: &mut Context<Self>) {
2689        self.snapshot.get_mut().use_extended_diff_range = use_extended;
2690    }
2691
2692    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2693        self.read(cx)
2694            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2695            .nth(1)
2696            .is_some()
2697    }
2698
2699    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2700        let snapshot = self.read(cx);
2701        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2702        let offset_range = range.to_offset(&snapshot);
2703        cursor.seek(&offset_range.start, Bias::Left);
2704        while let Some(item) = cursor.item() {
2705            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2706                break;
2707            }
2708            if item.hunk_info().is_some() {
2709                return true;
2710            }
2711            cursor.next();
2712        }
2713        false
2714    }
2715
2716    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2717        let snapshot = self.read(cx);
2718        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2719        for range in ranges {
2720            let range = range.to_point(&snapshot);
2721            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2722            let end = (snapshot.point_to_offset(Point::new(range.end.row + 1, 0)) + 1usize)
2723                .min(snapshot.len());
2724            cursor.seek(&start, Bias::Right);
2725            while let Some(item) = cursor.item() {
2726                if *cursor.start() >= end {
2727                    break;
2728                }
2729                if item.hunk_info().is_some() {
2730                    return true;
2731                }
2732                cursor.next();
2733            }
2734        }
2735        false
2736    }
2737
2738    pub fn expand_or_collapse_diff_hunks_inner(
2739        &mut self,
2740        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2741        expand: bool,
2742        cx: &mut Context<Self>,
2743    ) {
2744        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2745            return;
2746        }
2747        self.sync_mut(cx);
2748        let mut snapshot = self.snapshot.get_mut();
2749        let mut excerpt_edits = Vec::new();
2750        let mut last_hunk_row = None;
2751        for (range, end_excerpt_id) in ranges {
2752            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2753                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2754                    continue;
2755                }
2756                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2757                    continue;
2758                }
2759                let start = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.start);
2760                let end = Anchor::in_buffer(diff_hunk.excerpt_id, diff_hunk.buffer_range.end);
2761                let start = snapshot.excerpt_offset_for_anchor(&start);
2762                let end = snapshot.excerpt_offset_for_anchor(&end);
2763                last_hunk_row = Some(diff_hunk.row_range.start);
2764                excerpt_edits.push(text::Edit {
2765                    old: start..end,
2766                    new: start..end,
2767                });
2768            }
2769        }
2770
2771        let edits = Self::sync_diff_transforms(
2772            &mut snapshot,
2773            excerpt_edits,
2774            DiffChangeKind::ExpandOrCollapseHunks { expand },
2775        );
2776        if !edits.is_empty() {
2777            self.subscriptions.publish(edits);
2778        }
2779        cx.emit(Event::DiffHunksToggled);
2780        cx.emit(Event::Edited {
2781            edited_buffer: None,
2782        });
2783    }
2784
2785    pub fn expand_or_collapse_diff_hunks(
2786        &mut self,
2787        ranges: Vec<Range<Anchor>>,
2788        expand: bool,
2789        cx: &mut Context<Self>,
2790    ) {
2791        let snapshot = self.snapshot.borrow().clone();
2792        let ranges = ranges.iter().map(move |range| {
2793            let end_excerpt_id = range.end.excerpt_id;
2794            let range = range.to_point(&snapshot);
2795            let mut peek_end = range.end;
2796            if range.end.row < snapshot.max_row().0 {
2797                peek_end = Point::new(range.end.row + 1, 0);
2798            };
2799            (range.start..peek_end, end_excerpt_id)
2800        });
2801        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2802    }
2803
2804    pub fn resize_excerpt(
2805        &mut self,
2806        id: ExcerptId,
2807        range: Range<text::Anchor>,
2808        cx: &mut Context<Self>,
2809    ) {
2810        self.sync_mut(cx);
2811
2812        let mut snapshot = self.snapshot.get_mut();
2813        let locator = snapshot.excerpt_locator_for_id(id);
2814        let mut new_excerpts = SumTree::default();
2815        let mut cursor = snapshot
2816            .excerpts
2817            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2818        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2819
2820        let prefix = cursor.slice(&Some(locator), Bias::Left);
2821        new_excerpts.append(prefix, ());
2822
2823        let mut excerpt = cursor.item().unwrap().clone();
2824        let old_text_len = excerpt.text_summary.len;
2825
2826        excerpt.range.context.start = range.start;
2827        excerpt.range.context.end = range.end;
2828        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2829
2830        excerpt.text_summary = excerpt
2831            .buffer
2832            .text_summary_for_range(excerpt.range.context.clone());
2833
2834        let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2835        let old_start_offset = cursor.start().1;
2836        let new_text_len = excerpt.text_summary.len;
2837        let edit = Edit {
2838            old: old_start_offset..old_start_offset + old_text_len,
2839            new: new_start_offset..new_start_offset + new_text_len,
2840        };
2841
2842        if let Some(last_edit) = edits.last_mut() {
2843            if last_edit.old.end == edit.old.start {
2844                last_edit.old.end = edit.old.end;
2845                last_edit.new.end = edit.new.end;
2846            } else {
2847                edits.push(edit);
2848            }
2849        } else {
2850            edits.push(edit);
2851        }
2852
2853        new_excerpts.push(excerpt, ());
2854
2855        cursor.next();
2856
2857        new_excerpts.append(cursor.suffix(), ());
2858
2859        drop(cursor);
2860        snapshot.excerpts = new_excerpts;
2861
2862        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2863        if !edits.is_empty() {
2864            self.subscriptions.publish(edits);
2865        }
2866        cx.emit(Event::Edited {
2867            edited_buffer: None,
2868        });
2869        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2870        cx.notify();
2871    }
2872
2873    pub fn expand_excerpts(
2874        &mut self,
2875        ids: impl IntoIterator<Item = ExcerptId>,
2876        line_count: u32,
2877        direction: ExpandExcerptDirection,
2878        cx: &mut Context<Self>,
2879    ) {
2880        if line_count == 0 {
2881            return;
2882        }
2883        self.sync_mut(cx);
2884        if !self.excerpts_by_path.is_empty() {
2885            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2886            return;
2887        }
2888        let mut snapshot = self.snapshot.get_mut();
2889
2890        let ids = ids.into_iter().collect::<Vec<_>>();
2891        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2892        let mut new_excerpts = SumTree::default();
2893        let mut cursor = snapshot
2894            .excerpts
2895            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2896        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2897
2898        for locator in &locators {
2899            let prefix = cursor.slice(&Some(locator), Bias::Left);
2900            new_excerpts.append(prefix, ());
2901
2902            let mut excerpt = cursor.item().unwrap().clone();
2903            let old_text_len = excerpt.text_summary.len;
2904
2905            let up_line_count = if direction.should_expand_up() {
2906                line_count
2907            } else {
2908                0
2909            };
2910
2911            let start_row = excerpt
2912                .range
2913                .context
2914                .start
2915                .to_point(&excerpt.buffer)
2916                .row
2917                .saturating_sub(up_line_count);
2918            let start_point = Point::new(start_row, 0);
2919            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2920
2921            let down_line_count = if direction.should_expand_down() {
2922                line_count
2923            } else {
2924                0
2925            };
2926
2927            let mut end_point = excerpt.buffer.clip_point(
2928                excerpt.range.context.end.to_point(&excerpt.buffer)
2929                    + Point::new(down_line_count, 0),
2930                Bias::Left,
2931            );
2932            end_point.column = excerpt.buffer.line_len(end_point.row);
2933            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2934            excerpt.max_buffer_row = end_point.row;
2935
2936            excerpt.text_summary = excerpt
2937                .buffer
2938                .text_summary_for_range(excerpt.range.context.clone());
2939
2940            let new_start_offset = ExcerptDimension(new_excerpts.summary().text.len);
2941            let old_start_offset = cursor.start().1;
2942            let new_text_len = excerpt.text_summary.len;
2943            let edit = Edit {
2944                old: old_start_offset..old_start_offset + old_text_len,
2945                new: new_start_offset..new_start_offset + new_text_len,
2946            };
2947
2948            if let Some(last_edit) = edits.last_mut() {
2949                if last_edit.old.end == edit.old.start {
2950                    last_edit.old.end = edit.old.end;
2951                    last_edit.new.end = edit.new.end;
2952                } else {
2953                    edits.push(edit);
2954                }
2955            } else {
2956                edits.push(edit);
2957            }
2958
2959            new_excerpts.push(excerpt, ());
2960
2961            cursor.next();
2962        }
2963
2964        new_excerpts.append(cursor.suffix(), ());
2965
2966        drop(cursor);
2967        snapshot.excerpts = new_excerpts;
2968
2969        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2970        if !edits.is_empty() {
2971            self.subscriptions.publish(edits);
2972        }
2973        cx.emit(Event::Edited {
2974            edited_buffer: None,
2975        });
2976        cx.emit(Event::ExcerptsExpanded { ids });
2977        cx.notify();
2978    }
2979
2980    #[ztracing::instrument(skip_all)]
2981    fn sync(&self, cx: &App) {
2982        let changed = self.buffer_changed_since_sync.replace(false);
2983        if !changed {
2984            return;
2985        }
2986        let edits = Self::sync_from_buffer_changes(
2987            &mut self.snapshot.borrow_mut(),
2988            &self.buffers,
2989            &self.diffs,
2990            cx,
2991        );
2992        if !edits.is_empty() {
2993            self.subscriptions.publish(edits);
2994        }
2995    }
2996
2997    fn sync_mut(&mut self, cx: &App) {
2998        let changed = self.buffer_changed_since_sync.replace(false);
2999        if !changed {
3000            return;
3001        }
3002        let edits =
3003            Self::sync_from_buffer_changes(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
3004
3005        if !edits.is_empty() {
3006            self.subscriptions.publish(edits);
3007        }
3008    }
3009
3010    fn sync_from_buffer_changes(
3011        snapshot: &mut MultiBufferSnapshot,
3012        buffers: &BTreeMap<BufferId, BufferState>,
3013        diffs: &HashMap<BufferId, DiffState>,
3014        cx: &App,
3015    ) -> Vec<Edit<MultiBufferOffset>> {
3016        let MultiBufferSnapshot {
3017            excerpts,
3018            buffer_locators: _,
3019            diffs: buffer_diff,
3020            diff_transforms: _,
3021            non_text_state_update_count,
3022            edit_count,
3023            is_dirty,
3024            has_deleted_file,
3025            has_conflict,
3026            has_inverted_diff: _,
3027            singleton: _,
3028            excerpt_ids: _,
3029            replaced_excerpts: _,
3030            trailing_excerpt_update_count: _,
3031            all_diff_hunks_expanded: _,
3032            show_deleted_hunks: _,
3033            use_extended_diff_range: _,
3034            show_headers: _,
3035        } = snapshot;
3036        *is_dirty = false;
3037        *has_deleted_file = false;
3038        *has_conflict = false;
3039
3040        if !diffs.is_empty() {
3041            let mut diffs_to_add = Vec::new();
3042            for (id, diff) in diffs {
3043                // For inverted diffs, we excerpt the diff base texts in the multibuffer
3044                // and use the diff hunk base text ranges to compute diff transforms.
3045                // Those base text ranges are usize, so make sure if the base text changed
3046                // we also update the diff snapshot so that we don't use stale offsets
3047                if buffer_diff.get(id).is_none_or(|existing_diff| {
3048                    if !existing_diff.is_inverted {
3049                        return false;
3050                    }
3051                    let base_text = diff.diff.read(cx).base_text_buffer().read(cx);
3052                    base_text.remote_id() != existing_diff.base_text().remote_id()
3053                        || base_text
3054                            .version()
3055                            .changed_since(existing_diff.base_text().version())
3056                }) {
3057                    if diffs_to_add.capacity() == 0 {
3058                        // we'd rather overallocate than reallocate as buffer diffs are quite big
3059                        // meaning re-allocations will be fairly expensive
3060                        diffs_to_add.reserve(diffs.len());
3061                    }
3062                    diffs_to_add.push((*id, diff.snapshot(cx)));
3063                }
3064            }
3065            buffer_diff.extend(diffs_to_add);
3066        }
3067
3068        let mut excerpts_to_edit = Vec::new();
3069        let mut non_text_state_updated = false;
3070        let mut edited = false;
3071        for buffer_state in buffers.values() {
3072            let buffer = buffer_state.buffer.read(cx);
3073            let version = buffer.version();
3074            let non_text_state_update_count = buffer.non_text_state_update_count();
3075
3076            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
3077            let buffer_non_text_state_updated =
3078                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
3079            if buffer_edited || buffer_non_text_state_updated {
3080                *buffer_state.last_version.borrow_mut() = version;
3081                buffer_state
3082                    .last_non_text_state_update_count
3083                    .set(non_text_state_update_count);
3084                excerpts_to_edit.extend(
3085                    buffer_state
3086                        .excerpts
3087                        .iter()
3088                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3089                );
3090            }
3091
3092            edited |= buffer_edited;
3093            non_text_state_updated |= buffer_non_text_state_updated;
3094            *is_dirty |= buffer.is_dirty();
3095            *has_deleted_file |= buffer
3096                .file()
3097                .is_some_and(|file| file.disk_state().is_deleted());
3098            *has_conflict |= buffer.has_conflict();
3099        }
3100        if edited {
3101            *edit_count += 1;
3102        }
3103        if non_text_state_updated {
3104            *non_text_state_update_count += 1;
3105        }
3106
3107        excerpts_to_edit.sort_unstable_by_key(|&(locator, _, _)| locator);
3108
3109        let mut edits = Vec::new();
3110        let mut new_excerpts = SumTree::default();
3111        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
3112
3113        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3114            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
3115            let old_excerpt = cursor.item().unwrap();
3116            let buffer = buffer.read(cx);
3117            let buffer_id = buffer.remote_id();
3118            let mut new_excerpt;
3119            if buffer_edited {
3120                edits.extend(
3121                    buffer
3122                        .edits_since_in_range::<usize>(
3123                            old_excerpt.buffer.version(),
3124                            old_excerpt.range.context.clone(),
3125                        )
3126                        .map(|edit| {
3127                            let excerpt_old_start = cursor.start().1;
3128                            let excerpt_new_start =
3129                                ExcerptDimension(new_excerpts.summary().text.len);
3130                            let old_start = excerpt_old_start + edit.old.start;
3131                            let old_end = excerpt_old_start + edit.old.end;
3132                            let new_start = excerpt_new_start + edit.new.start;
3133                            let new_end = excerpt_new_start + edit.new.end;
3134                            Edit {
3135                                old: old_start..old_end,
3136                                new: new_start..new_end,
3137                            }
3138                        }),
3139                );
3140
3141                new_excerpt = Excerpt::new(
3142                    old_excerpt.id,
3143                    locator.clone(),
3144                    buffer_id,
3145                    Arc::new(buffer.snapshot()),
3146                    old_excerpt.range.clone(),
3147                    old_excerpt.has_trailing_newline,
3148                );
3149            } else {
3150                new_excerpt = old_excerpt.clone();
3151                new_excerpt.buffer = Arc::new(buffer.snapshot());
3152            }
3153
3154            new_excerpts.push(new_excerpt, ());
3155            cursor.next();
3156        }
3157        new_excerpts.append(cursor.suffix(), ());
3158
3159        drop(cursor);
3160        *excerpts = new_excerpts;
3161
3162        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
3163    }
3164
3165    fn sync_diff_transforms(
3166        snapshot: &mut MultiBufferSnapshot,
3167        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3168        change_kind: DiffChangeKind,
3169    ) -> Vec<Edit<MultiBufferOffset>> {
3170        if excerpt_edits.is_empty() {
3171            return vec![];
3172        }
3173
3174        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
3175        let mut old_diff_transforms = snapshot
3176            .diff_transforms
3177            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
3178        let mut new_diff_transforms = SumTree::default();
3179        let mut old_expanded_hunks = HashSet::default();
3180        let mut output_edits = Vec::new();
3181        let mut output_delta = 0_isize;
3182        let mut at_transform_boundary = true;
3183        let mut end_of_current_insert = None;
3184
3185        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3186        while let Some(edit) = excerpt_edits.next() {
3187            excerpts.seek_forward(&edit.new.start, Bias::Right);
3188            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3189                excerpts.prev();
3190            }
3191
3192            // Keep any transforms that are before the edit.
3193            if at_transform_boundary {
3194                at_transform_boundary = false;
3195                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3196                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3197                if let Some(transform) = old_diff_transforms.item()
3198                    && old_diff_transforms.end().0 == edit.old.start
3199                    && old_diff_transforms.start().0 < edit.old.start
3200                {
3201                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
3202                    old_diff_transforms.next();
3203                }
3204            }
3205
3206            // Compute the start of the edit in output coordinates.
3207            let edit_start_overshoot = edit.old.start - old_diff_transforms.start().0;
3208            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3209            let edit_new_start =
3210                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
3211
3212            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
3213                &edit,
3214                &mut excerpts,
3215                &mut old_diff_transforms,
3216                &mut new_diff_transforms,
3217                &mut end_of_current_insert,
3218                &mut old_expanded_hunks,
3219                snapshot,
3220                change_kind,
3221            );
3222
3223            // Compute the end of the edit in output coordinates.
3224            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3225            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3226            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot;
3227            let edit_new_end = new_diff_transforms.summary().output.len + edit_new_end_overshoot;
3228            let output_edit = Edit {
3229                old: edit_old_start..edit_old_end,
3230                new: edit_new_start..edit_new_end,
3231            };
3232
3233            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3234            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3235            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3236                output_edits.push(output_edit);
3237            }
3238
3239            // If this is the last edit that intersects the current diff transform,
3240            // then recreate the content up to the end of this transform, to prepare
3241            // for reusing additional slices of the old transforms.
3242            if excerpt_edits
3243                .peek()
3244                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3245            {
3246                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3247                    && match old_diff_transforms.item() {
3248                        Some(DiffTransform::BufferContent {
3249                            inserted_hunk_info: Some(hunk),
3250                            ..
3251                        }) => excerpts.item().is_some_and(|excerpt| {
3252                            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id)
3253                                && diff.is_inverted
3254                            {
3255                                return true;
3256                            }
3257                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3258                        }),
3259                        _ => true,
3260                    };
3261
3262                let mut excerpt_offset = edit.new.end;
3263                if !keep_next_old_transform {
3264                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3265                    old_diff_transforms.next();
3266                }
3267
3268                old_expanded_hunks.clear();
3269                Self::push_buffer_content_transform(
3270                    snapshot,
3271                    &mut new_diff_transforms,
3272                    excerpt_offset,
3273                    end_of_current_insert,
3274                );
3275                at_transform_boundary = true;
3276            }
3277        }
3278
3279        // Keep any transforms that are after the last edit.
3280        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3281
3282        // Ensure there's always at least one buffer content transform.
3283        if new_diff_transforms.is_empty() {
3284            new_diff_transforms.push(
3285                DiffTransform::BufferContent {
3286                    summary: Default::default(),
3287                    inserted_hunk_info: None,
3288                },
3289                (),
3290            );
3291        }
3292
3293        drop(old_diff_transforms);
3294        drop(excerpts);
3295        snapshot.diff_transforms = new_diff_transforms;
3296        snapshot.edit_count += 1;
3297
3298        #[cfg(any(test, feature = "test-support"))]
3299        snapshot.check_invariants();
3300        output_edits
3301    }
3302
3303    fn recompute_diff_transforms_for_edit(
3304        edit: &Edit<ExcerptOffset>,
3305        excerpts: &mut Cursor<Excerpt, ExcerptOffset>,
3306        old_diff_transforms: &mut Cursor<
3307            DiffTransform,
3308            Dimensions<ExcerptOffset, MultiBufferOffset>,
3309        >,
3310        new_diff_transforms: &mut SumTree<DiffTransform>,
3311        end_of_current_insert: &mut Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3312        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3313        snapshot: &MultiBufferSnapshot,
3314        change_kind: DiffChangeKind,
3315    ) -> bool {
3316        log::trace!(
3317            "recomputing diff transform for edit {:?} => {:?}",
3318            edit.old.start..edit.old.end,
3319            edit.new.start..edit.new.end
3320        );
3321
3322        // Record which hunks were previously expanded.
3323        while let Some(item) = old_diff_transforms.item() {
3324            if let Some(hunk_info) = item.hunk_info() {
3325                log::trace!(
3326                    "previously expanded hunk at {:?}",
3327                    old_diff_transforms.start()
3328                );
3329                old_expanded_hunks.insert(hunk_info);
3330            }
3331            if old_diff_transforms.end().0 > edit.old.end {
3332                break;
3333            }
3334            old_diff_transforms.next();
3335        }
3336
3337        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3338        // For inverted diffs, hunks are always shown, so we can't skip this.
3339        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3340        if old_expanded_hunks.is_empty()
3341            && change_kind == DiffChangeKind::BufferEdited
3342            && !all_diff_hunks_expanded
3343            && !snapshot.has_inverted_diff
3344        {
3345            return false;
3346        }
3347
3348        // Visit each excerpt that intersects the edit.
3349        let mut did_expand_hunks = false;
3350        while let Some(excerpt) = excerpts.item() {
3351            // Recompute the expanded hunks in the portion of the excerpt that
3352            // intersects the edit.
3353            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3354                let buffer = &excerpt.buffer;
3355                let excerpt_start = *excerpts.start();
3356                let excerpt_end = excerpt_start + excerpt.text_summary.len;
3357                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3358                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3359                let edit_buffer_start =
3360                    excerpt_buffer_start + edit.new.start.saturating_sub(excerpt_start);
3361                let edit_buffer_end =
3362                    excerpt_buffer_start + edit.new.end.saturating_sub(excerpt_start);
3363                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3364
3365                if diff.is_inverted {
3366                    for hunk in diff.hunks_intersecting_base_text_range(
3367                        edit_buffer_start..edit_buffer_end,
3368                        diff.original_buffer_snapshot(),
3369                    ) {
3370                        did_expand_hunks = true;
3371                        let hunk_buffer_range = hunk.diff_base_byte_range.clone();
3372                        if hunk_buffer_range.start < excerpt_buffer_start {
3373                            log::trace!("skipping hunk that starts before excerpt");
3374                            continue;
3375                        }
3376                        hunk_buffer_range.end.to_point(&excerpt.buffer);
3377                        let hunk_excerpt_start = excerpt_start
3378                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3379                        let hunk_excerpt_end = excerpt_end
3380                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3381                        Self::push_buffer_content_transform(
3382                            snapshot,
3383                            new_diff_transforms,
3384                            hunk_excerpt_start,
3385                            *end_of_current_insert,
3386                        );
3387                        if !hunk_buffer_range.is_empty() {
3388                            let hunk_info = DiffTransformHunkInfo {
3389                                excerpt_id: excerpt.id,
3390                                hunk_start_anchor: hunk.buffer_range.start,
3391                                hunk_secondary_status: hunk.secondary_status,
3392                                is_logically_deleted: true,
3393                            };
3394                            *end_of_current_insert =
3395                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3396                        }
3397                    }
3398                } else {
3399                    let edit_anchor_range = buffer.anchor_before(edit_buffer_start)
3400                        ..buffer.anchor_after(edit_buffer_end);
3401                    for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3402                        if hunk.is_created_file() && !all_diff_hunks_expanded {
3403                            continue;
3404                        }
3405
3406                        let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3407                        if hunk_buffer_range.start < excerpt_buffer_start {
3408                            log::trace!("skipping hunk that starts before excerpt");
3409                            continue;
3410                        }
3411
3412                        let hunk_info = DiffTransformHunkInfo {
3413                            excerpt_id: excerpt.id,
3414                            hunk_start_anchor: hunk.buffer_range.start,
3415                            hunk_secondary_status: hunk.secondary_status,
3416                            is_logically_deleted: false,
3417                        };
3418
3419                        let hunk_excerpt_start = excerpt_start
3420                            + hunk_buffer_range.start.saturating_sub(excerpt_buffer_start);
3421                        let hunk_excerpt_end = excerpt_end
3422                            .min(excerpt_start + (hunk_buffer_range.end - excerpt_buffer_start));
3423
3424                        Self::push_buffer_content_transform(
3425                            snapshot,
3426                            new_diff_transforms,
3427                            hunk_excerpt_start,
3428                            *end_of_current_insert,
3429                        );
3430
3431                        // For every existing hunk, determine if it was previously expanded
3432                        // and if it should currently be expanded.
3433                        let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3434                        let should_expand_hunk = match &change_kind {
3435                            DiffChangeKind::DiffUpdated { base_changed: true } => {
3436                                was_previously_expanded || all_diff_hunks_expanded
3437                            }
3438                            DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3439                                let intersects = hunk_buffer_range.is_empty()
3440                                    || hunk_buffer_range.end > edit_buffer_start;
3441                                if *expand {
3442                                    intersects || was_previously_expanded || all_diff_hunks_expanded
3443                                } else {
3444                                    !intersects
3445                                        && (was_previously_expanded || all_diff_hunks_expanded)
3446                                }
3447                            }
3448                            _ => was_previously_expanded || all_diff_hunks_expanded,
3449                        };
3450
3451                        if should_expand_hunk {
3452                            did_expand_hunks = true;
3453                            log::trace!(
3454                                "expanding hunk {:?}, excerpt:{:?}",
3455                                hunk_excerpt_start..hunk_excerpt_end,
3456                                excerpt.id
3457                            );
3458
3459                            if !hunk.diff_base_byte_range.is_empty()
3460                                && hunk_buffer_range.start >= edit_buffer_start
3461                                && hunk_buffer_range.start <= excerpt_buffer_end
3462                                && snapshot.show_deleted_hunks
3463                            {
3464                                let base_text = diff.base_text();
3465                                let mut text_cursor =
3466                                    base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3467                                let mut base_text_summary = text_cursor
3468                                    .summary::<TextSummary>(hunk.diff_base_byte_range.end);
3469
3470                                let mut has_trailing_newline = false;
3471                                if base_text_summary.last_line_chars > 0 {
3472                                    base_text_summary += TextSummary::newline();
3473                                    has_trailing_newline = true;
3474                                }
3475
3476                                new_diff_transforms.push(
3477                                    DiffTransform::DeletedHunk {
3478                                        base_text_byte_range: hunk.diff_base_byte_range.clone(),
3479                                        summary: base_text_summary,
3480                                        buffer_id: excerpt.buffer_id,
3481                                        hunk_info,
3482                                        has_trailing_newline,
3483                                    },
3484                                    (),
3485                                );
3486                            }
3487
3488                            if !hunk_buffer_range.is_empty() {
3489                                *end_of_current_insert =
3490                                    Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3491                            }
3492                        }
3493                    }
3494                }
3495            }
3496
3497            if excerpts.end() <= edit.new.end {
3498                excerpts.next();
3499            } else {
3500                break;
3501            }
3502        }
3503
3504        did_expand_hunks || !old_expanded_hunks.is_empty()
3505    }
3506
3507    fn append_diff_transforms(
3508        new_transforms: &mut SumTree<DiffTransform>,
3509        subtree: SumTree<DiffTransform>,
3510    ) {
3511        if let Some(DiffTransform::BufferContent {
3512            inserted_hunk_info,
3513            summary,
3514        }) = subtree.first()
3515            && Self::extend_last_buffer_content_transform(
3516                new_transforms,
3517                *inserted_hunk_info,
3518                *summary,
3519            )
3520        {
3521            let mut cursor = subtree.cursor::<()>(());
3522            cursor.next();
3523            cursor.next();
3524            new_transforms.append(cursor.suffix(), ());
3525            return;
3526        }
3527        new_transforms.append(subtree, ());
3528    }
3529
3530    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3531        if let DiffTransform::BufferContent {
3532            inserted_hunk_info: inserted_hunk_anchor,
3533            summary,
3534        } = transform
3535            && Self::extend_last_buffer_content_transform(
3536                new_transforms,
3537                inserted_hunk_anchor,
3538                summary,
3539            )
3540        {
3541            return;
3542        }
3543        new_transforms.push(transform, ());
3544    }
3545
3546    fn push_buffer_content_transform(
3547        old_snapshot: &MultiBufferSnapshot,
3548        new_transforms: &mut SumTree<DiffTransform>,
3549        end_offset: ExcerptOffset,
3550        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3551    ) {
3552        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3553            (end_offset.min(insertion_end_offset), Some(hunk_info))
3554        });
3555        let unchanged_region = [(end_offset, None)];
3556
3557        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3558        {
3559            let start_offset = new_transforms.summary().excerpt_len();
3560            if end_offset <= start_offset {
3561                continue;
3562            }
3563            let summary_to_add = old_snapshot
3564                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3565
3566            if !Self::extend_last_buffer_content_transform(
3567                new_transforms,
3568                inserted_hunk_info,
3569                summary_to_add,
3570            ) {
3571                new_transforms.push(
3572                    DiffTransform::BufferContent {
3573                        summary: summary_to_add,
3574                        inserted_hunk_info,
3575                    },
3576                    (),
3577                )
3578            }
3579        }
3580    }
3581
3582    fn extend_last_buffer_content_transform(
3583        new_transforms: &mut SumTree<DiffTransform>,
3584        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3585        summary_to_add: MBTextSummary,
3586    ) -> bool {
3587        let mut did_extend = false;
3588        new_transforms.update_last(
3589            |last_transform| {
3590                if let DiffTransform::BufferContent {
3591                    summary,
3592                    inserted_hunk_info: inserted_hunk_anchor,
3593                } = last_transform
3594                    && *inserted_hunk_anchor == new_inserted_hunk_info
3595                {
3596                    *summary += summary_to_add;
3597                    did_extend = true;
3598                }
3599            },
3600            (),
3601        );
3602        did_extend
3603    }
3604}
3605
3606fn build_excerpt_ranges(
3607    ranges: impl IntoIterator<Item = Range<Point>>,
3608    context_line_count: u32,
3609    buffer_snapshot: &BufferSnapshot,
3610) -> Vec<ExcerptRange<Point>> {
3611    ranges
3612        .into_iter()
3613        .map(|range| {
3614            let start_row = range.start.row.saturating_sub(context_line_count);
3615            let start = Point::new(start_row, 0);
3616            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3617            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3618            ExcerptRange {
3619                context: start..end,
3620                primary: range,
3621            }
3622        })
3623        .collect()
3624}
3625
3626#[cfg(any(test, feature = "test-support"))]
3627impl MultiBuffer {
3628    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3629        let buffer = cx.new(|cx| Buffer::local(text, cx));
3630        cx.new(|cx| Self::singleton(buffer, cx))
3631    }
3632
3633    pub fn build_multi<const COUNT: usize>(
3634        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3635        cx: &mut gpui::App,
3636    ) -> Entity<Self> {
3637        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3638        for (text, ranges) in excerpts {
3639            let buffer = cx.new(|cx| Buffer::local(text, cx));
3640            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3641            multi.update(cx, |multi, cx| {
3642                multi.push_excerpts(buffer, excerpt_ranges, cx)
3643            });
3644        }
3645
3646        multi
3647    }
3648
3649    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3650        cx.new(|cx| Self::singleton(buffer, cx))
3651    }
3652
3653    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3654        cx.new(|cx| {
3655            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3656            let mutation_count = rng.random_range(1..=5);
3657            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3658            multibuffer
3659        })
3660    }
3661
3662    pub fn randomly_edit(
3663        &mut self,
3664        rng: &mut impl rand::Rng,
3665        edit_count: usize,
3666        cx: &mut Context<Self>,
3667    ) {
3668        use util::RandomCharIter;
3669
3670        let snapshot = self.read(cx);
3671        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3672        let mut last_end = None;
3673        for _ in 0..edit_count {
3674            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3675                break;
3676            }
3677
3678            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3679            let end =
3680                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3681            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3682            last_end = Some(end);
3683
3684            let mut range = start..end;
3685            if rng.random_bool(0.2) {
3686                mem::swap(&mut range.start, &mut range.end);
3687            }
3688
3689            let new_text_len = rng.random_range(0..10);
3690            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3691
3692            edits.push((range, new_text.into()));
3693        }
3694        log::info!("mutating multi-buffer with {:?}", edits);
3695        drop(snapshot);
3696
3697        self.edit(edits, None, cx);
3698    }
3699
3700    pub fn randomly_edit_excerpts(
3701        &mut self,
3702        rng: &mut impl rand::Rng,
3703        mutation_count: usize,
3704        cx: &mut Context<Self>,
3705    ) {
3706        use rand::prelude::*;
3707        use std::env;
3708        use util::RandomCharIter;
3709
3710        let max_excerpts = env::var("MAX_EXCERPTS")
3711            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3712            .unwrap_or(5);
3713
3714        let mut buffers = Vec::new();
3715        for _ in 0..mutation_count {
3716            if rng.random_bool(0.05) {
3717                log::info!("Clearing multi-buffer");
3718                self.clear(cx);
3719                continue;
3720            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3721                let ids = self.excerpt_ids();
3722                let mut excerpts = HashSet::default();
3723                for _ in 0..rng.random_range(0..ids.len()) {
3724                    excerpts.extend(ids.choose(rng).copied());
3725                }
3726
3727                let line_count = rng.random_range(0..5);
3728
3729                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3730
3731                self.expand_excerpts(
3732                    excerpts.iter().cloned(),
3733                    line_count,
3734                    ExpandExcerptDirection::UpAndDown,
3735                    cx,
3736                );
3737                continue;
3738            }
3739
3740            let excerpt_ids = self.excerpt_ids();
3741            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3742                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3743                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3744                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3745                    let buffer = buffers.last().unwrap().read(cx);
3746                    log::info!(
3747                        "Creating new buffer {} with text: {:?}",
3748                        buffer.remote_id(),
3749                        buffer.text()
3750                    );
3751                    buffers.last().unwrap().clone()
3752                } else {
3753                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3754                };
3755
3756                let buffer = buffer_handle.read(cx);
3757                let buffer_text = buffer.text();
3758                let ranges = (0..rng.random_range(0..5))
3759                    .map(|_| {
3760                        let end_ix =
3761                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3762                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3763                        ExcerptRange::new(start_ix..end_ix)
3764                    })
3765                    .collect::<Vec<_>>();
3766                log::info!(
3767                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3768                    buffer_handle.read(cx).remote_id(),
3769                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3770                    ranges
3771                        .iter()
3772                        .map(|r| &buffer_text[r.context.clone()])
3773                        .collect::<Vec<_>>()
3774                );
3775
3776                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3777                log::info!("Inserted with ids: {:?}", excerpt_id);
3778            } else {
3779                let remove_count = rng.random_range(1..=excerpt_ids.len());
3780                let mut excerpts_to_remove = excerpt_ids
3781                    .choose_multiple(rng, remove_count)
3782                    .cloned()
3783                    .collect::<Vec<_>>();
3784                let snapshot = self.snapshot.borrow();
3785                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3786                drop(snapshot);
3787                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3788                self.remove_excerpts(excerpts_to_remove, cx);
3789            }
3790        }
3791    }
3792
3793    pub fn randomly_mutate(
3794        &mut self,
3795        rng: &mut impl rand::Rng,
3796        mutation_count: usize,
3797        cx: &mut Context<Self>,
3798    ) {
3799        use rand::prelude::*;
3800
3801        if rng.random_bool(0.7) || self.singleton {
3802            let buffer = self
3803                .buffers
3804                .values()
3805                .choose(rng)
3806                .map(|state| state.buffer.clone());
3807
3808            if let Some(buffer) = buffer {
3809                buffer.update(cx, |buffer, cx| {
3810                    if rng.random() {
3811                        buffer.randomly_edit(rng, mutation_count, cx);
3812                    } else {
3813                        buffer.randomly_undo_redo(rng, cx);
3814                    }
3815                });
3816            } else {
3817                self.randomly_edit(rng, mutation_count, cx);
3818            }
3819        } else {
3820            self.randomly_edit_excerpts(rng, mutation_count, cx);
3821        }
3822
3823        self.check_invariants(cx);
3824    }
3825
3826    fn check_invariants(&self, cx: &App) {
3827        self.read(cx).check_invariants();
3828    }
3829}
3830
3831impl EventEmitter<Event> for MultiBuffer {}
3832
3833impl MultiBufferSnapshot {
3834    pub fn text(&self) -> String {
3835        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3836            .map(|chunk| chunk.text)
3837            .collect()
3838    }
3839
3840    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3841        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3842            .flat_map(|c| c.chars().rev())
3843    }
3844
3845    fn reversed_chunks_in_range(
3846        &self,
3847        range: Range<MultiBufferOffset>,
3848    ) -> ReversedMultiBufferChunks<'_> {
3849        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3850        cursor.seek(&range.end);
3851        let current_chunks = cursor.region().as_ref().map(|region| {
3852            let start_overshoot = range.start.saturating_sub(region.range.start);
3853            let end_overshoot = range.end - region.range.start;
3854            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3855            let start = region.buffer_range.start + start_overshoot;
3856            region.buffer.reversed_chunks_in_range(start..end)
3857        });
3858        ReversedMultiBufferChunks {
3859            cursor,
3860            current_chunks,
3861            start: range.start,
3862            offset: range.end,
3863        }
3864    }
3865
3866    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3867        let offset = position.to_offset(self);
3868        self.text_for_range(offset..self.len())
3869            .flat_map(|chunk| chunk.chars())
3870    }
3871
3872    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3873        self.chunks(range, false).map(|chunk| chunk.text)
3874    }
3875
3876    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3877        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3878            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3879    }
3880
3881    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3882    where
3883        T: ToOffset,
3884    {
3885        let position = position.to_offset(self);
3886        position == self.clip_offset(position, Bias::Left)
3887            && self
3888                .bytes_in_range(position..self.len())
3889                .flatten()
3890                .copied()
3891                .take(needle.len())
3892                .eq(needle.bytes())
3893    }
3894
3895    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3896        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3897    }
3898
3899    pub fn diff_hunks_in_range<T: ToPoint>(
3900        &self,
3901        range: Range<T>,
3902    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3903        let query_range = range.start.to_point(self)..range.end.to_point(self);
3904        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3905            let diff = self.diffs.get(&buffer.remote_id())?;
3906            let iter: Box<dyn Iterator<Item = (DiffHunk, &BufferSnapshot, bool)>> =
3907                if diff.is_inverted {
3908                    let buffer_start = buffer.point_to_offset(buffer_range.start);
3909                    let buffer_end = buffer.point_to_offset(buffer_range.end);
3910                    Box::new(
3911                        diff.hunks_intersecting_base_text_range(
3912                            buffer_start..buffer_end,
3913                            diff.original_buffer_snapshot(),
3914                        )
3915                        .map(move |hunk| (hunk, buffer, true)),
3916                    )
3917                } else {
3918                    let buffer_start = buffer.anchor_before(buffer_range.start);
3919                    let buffer_end = buffer.anchor_after(buffer_range.end);
3920                    Box::new(
3921                        diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3922                            .map(move |hunk| (hunk, buffer, false)),
3923                    )
3924                };
3925            Some(iter.filter_map(|(hunk, buffer, is_inverted)| {
3926                if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3927                    return None;
3928                }
3929                let range = if is_inverted {
3930                    hunk.diff_base_byte_range.to_point(&buffer)
3931                } else {
3932                    hunk.range.clone()
3933                };
3934                Some((range, (hunk, is_inverted)))
3935            }))
3936        })
3937        .filter_map(move |(range, (hunk, is_inverted), excerpt)| {
3938            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3939            {
3940                return None;
3941            }
3942            let end_row = if range.end.column == 0 {
3943                range.end.row
3944            } else {
3945                range.end.row + 1
3946            };
3947
3948            let word_diffs =
3949                (!hunk.base_word_diffs.is_empty() || !hunk.buffer_word_diffs.is_empty())
3950                    .then(|| {
3951                        let mut word_diffs = Vec::new();
3952
3953                        if self.show_deleted_hunks || is_inverted {
3954                            let hunk_start_offset = if is_inverted {
3955                                Anchor::in_buffer(
3956                                    excerpt.id,
3957                                    excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start),
3958                                )
3959                                .to_offset(self)
3960                            } else {
3961                                Anchor::in_buffer(excerpt.id, hunk.buffer_range.start)
3962                                    .to_offset(self)
3963                            };
3964
3965                            word_diffs.extend(hunk.base_word_diffs.iter().map(|diff| {
3966                                hunk_start_offset + diff.start..hunk_start_offset + diff.end
3967                            }));
3968                        }
3969
3970                        if !is_inverted {
3971                            word_diffs.extend(hunk.buffer_word_diffs.into_iter().map(|diff| {
3972                                Anchor::range_in_buffer(excerpt.id, diff).to_offset(self)
3973                            }));
3974                        }
3975                        word_diffs
3976                    })
3977                    .unwrap_or_default();
3978
3979            let buffer_range = if is_inverted {
3980                excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start)
3981                    ..excerpt.buffer.anchor_before(hunk.diff_base_byte_range.end)
3982            } else {
3983                hunk.buffer_range.clone()
3984            };
3985            let status_kind = if hunk.buffer_range.start == hunk.buffer_range.end {
3986                DiffHunkStatusKind::Deleted
3987            } else if hunk.diff_base_byte_range.is_empty() {
3988                DiffHunkStatusKind::Added
3989            } else {
3990                DiffHunkStatusKind::Modified
3991            };
3992            Some(MultiBufferDiffHunk {
3993                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3994                buffer_id: excerpt.buffer_id,
3995                excerpt_id: excerpt.id,
3996                buffer_range,
3997                word_diffs,
3998                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3999                    ..BufferOffset(hunk.diff_base_byte_range.end),
4000                status: DiffHunkStatus {
4001                    kind: status_kind,
4002                    secondary: hunk.secondary_status,
4003                },
4004            })
4005        })
4006    }
4007
4008    fn excerpts_for_range<T: ToOffset>(
4009        &self,
4010        range: Range<T>,
4011    ) -> impl Iterator<Item = &Excerpt> + '_ {
4012        let range = range.start.to_offset(self)..range.end.to_offset(self);
4013        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4014        cursor.seek(&range.start);
4015        std::iter::from_fn(move || {
4016            let region = cursor.region()?;
4017            if region.range.start > range.end
4018                || region.range.start == range.end && region.range.start > range.start
4019            {
4020                return None;
4021            }
4022            let excerpt = region.excerpt;
4023            cursor.next_excerpt_forwards();
4024            Some(excerpt)
4025        })
4026    }
4027
4028    pub fn excerpt_ids_for_range<T: ToOffset>(
4029        &self,
4030        range: Range<T>,
4031    ) -> impl Iterator<Item = ExcerptId> + '_ {
4032        self.excerpts_for_range(range).map(|excerpt| excerpt.id)
4033    }
4034
4035    pub fn buffer_ids_for_range<T: ToOffset>(
4036        &self,
4037        range: Range<T>,
4038    ) -> impl Iterator<Item = BufferId> + '_ {
4039        self.excerpts_for_range(range)
4040            .map(|excerpt| excerpt.buffer_id)
4041    }
4042
4043    /// Resolves the given [`text::Anchor`]s to [`crate::Anchor`]s if the anchor is within a visible excerpt.
4044    ///
4045    /// The passed in anchors must be ordered.
4046    pub fn text_anchors_to_visible_anchors(
4047        &self,
4048        anchors: impl IntoIterator<Item = text::Anchor>,
4049    ) -> Vec<Option<Anchor>> {
4050        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4051        let mut anchors = anchors.into_iter().peekable();
4052        let mut result = Vec::new();
4053        'anchors: while let Some(anchor) = anchors.peek() {
4054            let Some(buffer_id) = anchor.buffer_id else {
4055                anchors.next();
4056                result.push(None);
4057                continue 'anchors;
4058            };
4059            let mut same_buffer_anchors =
4060                anchors.peeking_take_while(|a| a.buffer_id.is_some_and(|b| buffer_id == b));
4061
4062            if let Some(locators) = self.buffer_locators.get(&buffer_id) {
4063                let Some(mut next) = same_buffer_anchors.next() else {
4064                    continue 'anchors;
4065                };
4066                'excerpts: for locator in locators.iter() {
4067                    if cursor.seek_forward(&Some(locator), Bias::Left)
4068                        && let Some(excerpt) = cursor.item()
4069                    {
4070                        loop {
4071                            // anchor is before the first excerpt
4072                            if excerpt
4073                                .range
4074                                .context
4075                                .start
4076                                .cmp(&next, &excerpt.buffer)
4077                                .is_gt()
4078                            {
4079                                // so we skip it and try the next anchor
4080                                result.push(None);
4081                                match same_buffer_anchors.next() {
4082                                    Some(anchor) => next = anchor,
4083                                    None => continue 'anchors,
4084                                }
4085                            // anchor is within the excerpt
4086                            } else if excerpt
4087                                .range
4088                                .context
4089                                .end
4090                                .cmp(&next, &excerpt.buffer)
4091                                .is_ge()
4092                            {
4093                                // record it and all following anchors that are within
4094                                result.push(Some(Anchor::in_buffer(excerpt.id, next)));
4095                                result.extend(
4096                                    same_buffer_anchors
4097                                        .peeking_take_while(|a| {
4098                                            excerpt
4099                                                .range
4100                                                .context
4101                                                .end
4102                                                .cmp(a, &excerpt.buffer)
4103                                                .is_ge()
4104                                        })
4105                                        .map(|a| Some(Anchor::in_buffer(excerpt.id, a))),
4106                                );
4107                                match same_buffer_anchors.next() {
4108                                    Some(anchor) => next = anchor,
4109                                    None => continue 'anchors,
4110                                }
4111                            // anchor is after the excerpt, try the next one
4112                            } else {
4113                                continue 'excerpts;
4114                            }
4115                        }
4116                    }
4117                }
4118                // account for `next`
4119                result.push(None);
4120            }
4121            result.extend(same_buffer_anchors.map(|_| None));
4122        }
4123
4124        result
4125    }
4126
4127    pub fn ranges_to_buffer_ranges<T: ToOffset>(
4128        &self,
4129        ranges: impl Iterator<Item = Range<T>>,
4130    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
4131        ranges.flat_map(|range| {
4132            self.range_to_buffer_ranges((Bound::Included(range.start), Bound::Included(range.end)))
4133                .into_iter()
4134        })
4135    }
4136
4137    pub fn range_to_buffer_ranges<R, T>(
4138        &self,
4139        range: R,
4140    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)>
4141    where
4142        R: RangeBounds<T>,
4143        T: ToOffset,
4144    {
4145        self.range_to_buffer_ranges_with_context(range)
4146            .into_iter()
4147            .map(|(buffer, range, id, _context)| (buffer, range, id))
4148            .collect()
4149    }
4150
4151    pub fn range_to_buffer_ranges_with_context<R, T>(
4152        &self,
4153        range: R,
4154    ) -> Vec<(
4155        &BufferSnapshot,
4156        Range<BufferOffset>,
4157        ExcerptId,
4158        Range<text::Anchor>,
4159    )>
4160    where
4161        R: RangeBounds<T>,
4162        T: ToOffset,
4163    {
4164        let start = match range.start_bound() {
4165            Bound::Included(start) => start.to_offset(self),
4166            Bound::Excluded(_) => panic!("excluded start bound not supported"),
4167            Bound::Unbounded => MultiBufferOffset::ZERO,
4168        };
4169        let end_bound = match range.end_bound() {
4170            Bound::Included(end) => Bound::Included(end.to_offset(self)),
4171            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
4172            Bound::Unbounded => Bound::Unbounded,
4173        };
4174        let bounds = (Bound::Included(start), end_bound);
4175
4176        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4177        cursor.seek(&start);
4178
4179        let mut result: Vec<(
4180            &BufferSnapshot,
4181            Range<BufferOffset>,
4182            ExcerptId,
4183            Range<text::Anchor>,
4184        )> = Vec::new();
4185        while let Some(region) = cursor.region() {
4186            let dominated_by_end_bound = match end_bound {
4187                Bound::Included(end) => region.range.start > end,
4188                Bound::Excluded(end) => region.range.start >= end,
4189                Bound::Unbounded => false,
4190            };
4191            if dominated_by_end_bound {
4192                break;
4193            }
4194            if region.is_main_buffer {
4195                let start_overshoot = start.saturating_sub(region.range.start);
4196                let end_offset = match end_bound {
4197                    Bound::Included(end) | Bound::Excluded(end) => end,
4198                    Bound::Unbounded => region.range.end,
4199                };
4200                let end_overshoot = end_offset.saturating_sub(region.range.start);
4201                let start = region
4202                    .buffer_range
4203                    .end
4204                    .min(region.buffer_range.start + start_overshoot);
4205                let end = region
4206                    .buffer_range
4207                    .end
4208                    .min(region.buffer_range.start + end_overshoot);
4209                let context = region.excerpt.range.context.clone();
4210                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id, _)| {
4211                    *excerpt_id == region.excerpt.id && prev_range.end == start
4212                }) {
4213                    prev.1.end = end;
4214                } else {
4215                    result.push((region.buffer, start..end, region.excerpt.id, context));
4216                }
4217            }
4218            cursor.next();
4219        }
4220
4221        if let Some(excerpt) = cursor.excerpt() {
4222            let dominated_by_prev_excerpt =
4223                result.last().is_some_and(|(_, _, id, _)| *id == excerpt.id);
4224            if !dominated_by_prev_excerpt && excerpt.text_summary.len == 0 {
4225                let excerpt_position = self.len();
4226                if bounds.contains(&excerpt_position) {
4227                    let buffer_offset =
4228                        BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer));
4229                    let context = excerpt.range.context.clone();
4230                    result.push((
4231                        &excerpt.buffer,
4232                        buffer_offset..buffer_offset,
4233                        excerpt.id,
4234                        context,
4235                    ));
4236                }
4237            }
4238        }
4239
4240        result
4241    }
4242
4243    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
4244        &self,
4245        range: Range<T>,
4246    ) -> impl Iterator<
4247        Item = (
4248            &BufferSnapshot,
4249            Range<BufferOffset>,
4250            ExcerptId,
4251            Option<Anchor>,
4252        ),
4253    > + '_ {
4254        let start = range.start.to_offset(self);
4255        let end = range.end.to_offset(self);
4256
4257        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4258        cursor.seek(&start);
4259
4260        std::iter::from_fn(move || {
4261            let region = cursor.region()?;
4262            if region.range.start > end {
4263                return None;
4264            }
4265            let start_overshoot = start.saturating_sub(region.range.start);
4266            let end_overshoot = end.saturating_sub(region.range.start);
4267            let start = region
4268                .buffer_range
4269                .end
4270                .min(region.buffer_range.start + start_overshoot);
4271            let end = region
4272                .buffer_range
4273                .end
4274                .min(region.buffer_range.start + end_overshoot);
4275
4276            let region_excerpt_id = region.excerpt.id;
4277            let deleted_hunk_anchor = if region.is_main_buffer {
4278                None
4279            } else {
4280                Some(self.anchor_before(region.range.start))
4281            };
4282            let result = (
4283                region.buffer,
4284                start..end,
4285                region_excerpt_id,
4286                deleted_hunk_anchor,
4287            );
4288            cursor.next();
4289            Some(result)
4290        })
4291    }
4292
4293    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
4294    /// coordinates.
4295    ///
4296    /// The given callback will be called for every excerpt intersecting the given range. It will
4297    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
4298    /// The callback should return an iterator of metadata items from that buffer, each paired
4299    /// with a buffer range.
4300    ///
4301    /// The returned iterator yields each of these metadata items, paired with its range in
4302    /// multi-buffer coordinates.
4303    fn lift_buffer_metadata<'a, MBD, M, I>(
4304        &'a self,
4305        query_range: Range<MBD>,
4306        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
4307    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
4308    where
4309        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
4310        MBD: MultiBufferDimension
4311            + Ord
4312            + Sub<Output = MBD::TextDimension>
4313            + ops::Add<MBD::TextDimension, Output = MBD>
4314            + ops::AddAssign<MBD::TextDimension>,
4315        MBD::TextDimension: Sub<Output = MBD::TextDimension>
4316            + ops::Add<Output = MBD::TextDimension>
4317            + AddAssign<MBD::TextDimension>
4318            + Ord,
4319    {
4320        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4321        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
4322
4323        // Find the excerpt and buffer offset where the given range ends.
4324        cursor.seek(&query_range.end);
4325        let mut range_end = None;
4326        while let Some(region) = cursor.region() {
4327            if region.is_main_buffer {
4328                let mut buffer_end = region.buffer_range.start;
4329                let overshoot = if query_range.end > region.range.start {
4330                    query_range.end - region.range.start
4331                } else {
4332                    <MBD::TextDimension>::default()
4333                };
4334                buffer_end = buffer_end + overshoot;
4335                range_end = Some((region.excerpt.id, buffer_end));
4336                break;
4337            }
4338            cursor.next();
4339        }
4340
4341        cursor.seek(&query_range.start);
4342
4343        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4344            && region.range.start > MBD::default()
4345        {
4346            cursor.prev()
4347        } else if let Some(region) = cursor.region()
4348            && region.is_main_buffer
4349            && region.diff_hunk_status.is_some()
4350        {
4351            cursor.prev();
4352            if cursor.region().is_none_or(|region| region.is_main_buffer) {
4353                cursor.next();
4354            }
4355        }
4356
4357        iter::from_fn(move || {
4358            loop {
4359                let excerpt = cursor.excerpt()?;
4360
4361                // If we have already retrieved metadata for this excerpt, continue to use it.
4362                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4363                    .as_mut()
4364                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4365                {
4366                    Some(metadata)
4367                }
4368                // Otherwise, compute the intersection of the input range with the excerpt's range,
4369                // and retrieve the metadata for the resulting range.
4370                else {
4371                    let region = cursor.region()?;
4372                    let mut buffer_start;
4373                    if region.is_main_buffer {
4374                        buffer_start = region.buffer_range.start;
4375                        if query_range.start > region.range.start {
4376                            let overshoot = query_range.start - region.range.start;
4377                            buffer_start = buffer_start + overshoot;
4378                        }
4379                        buffer_start = buffer_start.min(region.buffer_range.end);
4380                    } else {
4381                        buffer_start = cursor.main_buffer_position()?;
4382                    };
4383                    let mut buffer_end = excerpt
4384                        .range
4385                        .context
4386                        .end
4387                        .summary::<MBD::TextDimension>(&excerpt.buffer);
4388                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4389                        && excerpt.id == end_excerpt_id
4390                    {
4391                        buffer_end = buffer_end.min(end_buffer_offset);
4392                    }
4393
4394                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4395                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4396                    })
4397                };
4398
4399                // Visit each metadata item.
4400                if let Some((metadata_buffer_range, metadata)) =
4401                    metadata_iter.and_then(Iterator::next)
4402                {
4403                    // Find the multibuffer regions that contain the start and end of
4404                    // the metadata item's range.
4405                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
4406                        while let Some(region) = cursor.region() {
4407                            if (region.is_main_buffer
4408                                && (region.buffer_range.end >= metadata_buffer_range.start
4409                                    || cursor.is_at_end_of_excerpt()))
4410                                || (!region.is_main_buffer
4411                                    && region.buffer_range.start == metadata_buffer_range.start)
4412                            {
4413                                break;
4414                            }
4415                            cursor.next();
4416                        }
4417                    }
4418                    let start_region = cursor.region()?.clone();
4419                    while let Some(region) = cursor.region() {
4420                        if region.is_main_buffer
4421                            && (region.buffer_range.end > metadata_buffer_range.end
4422                                || cursor.is_at_end_of_excerpt())
4423                        {
4424                            break;
4425                        }
4426                        cursor.next();
4427                    }
4428                    let end_region = cursor.region();
4429
4430                    // Convert the metadata item's range into multibuffer coordinates.
4431                    let mut start_position = start_region.range.start;
4432                    let region_buffer_start = start_region.buffer_range.start;
4433                    if start_region.is_main_buffer
4434                        && metadata_buffer_range.start > region_buffer_start
4435                    {
4436                        start_position =
4437                            start_position + (metadata_buffer_range.start - region_buffer_start);
4438                        start_position = start_position.min(start_region.range.end);
4439                    }
4440
4441                    let mut end_position = self.max_position();
4442                    if let Some(end_region) = &end_region {
4443                        end_position = end_region.range.start;
4444                        debug_assert!(end_region.is_main_buffer);
4445                        let region_buffer_start = end_region.buffer_range.start;
4446                        if metadata_buffer_range.end > region_buffer_start {
4447                            end_position =
4448                                end_position + (metadata_buffer_range.end - region_buffer_start);
4449                        }
4450                        end_position = end_position.min(end_region.range.end);
4451                    }
4452
4453                    if start_position <= query_range.end && end_position >= query_range.start {
4454                        return Some((start_position..end_position, metadata, excerpt));
4455                    }
4456                }
4457                // When there are no more metadata items for this excerpt, move to the next excerpt.
4458                else {
4459                    current_excerpt_metadata.take();
4460                    if let Some((end_excerpt_id, _)) = range_end
4461                        && excerpt.id == end_excerpt_id
4462                    {
4463                        return None;
4464                    }
4465                    cursor.next_excerpt_forwards();
4466                }
4467            }
4468        })
4469    }
4470
4471    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4472        let offset = position.to_offset(self);
4473
4474        let mut cursor = self
4475            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
4476            );
4477        cursor.seek(&DimensionPair {
4478            key: offset,
4479            value: None,
4480        });
4481        cursor.seek_to_start_of_current_excerpt();
4482        let excerpt = cursor.excerpt()?;
4483
4484        let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4485        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4486        let current_position = self
4487            .anchor_before(offset)
4488            .text_anchor
4489            .to_offset(&excerpt.buffer);
4490
4491        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4492            if diff.is_inverted {
4493                for hunk in diff.hunks_intersecting_base_text_range_rev(
4494                    excerpt_start..excerpt_end,
4495                    diff.original_buffer_snapshot(),
4496                ) {
4497                    if hunk.diff_base_byte_range.end >= current_position {
4498                        continue;
4499                    }
4500                    let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4501                    let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4502                    return Some(MultiBufferRow(start.row));
4503                }
4504            } else {
4505                let excerpt_end = excerpt
4506                    .buffer
4507                    .anchor_before(excerpt_end.min(current_position));
4508                for hunk in diff.hunks_intersecting_range_rev(
4509                    excerpt.range.context.start..excerpt_end,
4510                    &excerpt.buffer,
4511                ) {
4512                    let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4513                    if hunk_end >= current_position {
4514                        continue;
4515                    }
4516                    let start =
4517                        Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4518                    return Some(MultiBufferRow(start.row));
4519                }
4520            }
4521        }
4522
4523        loop {
4524            cursor.prev_excerpt();
4525            let excerpt = cursor.excerpt()?;
4526
4527            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4528                continue;
4529            };
4530            if diff.is_inverted {
4531                let Some(hunk) = diff
4532                    .hunks_intersecting_base_text_range_rev(
4533                        excerpt.range.context.to_offset(&excerpt.buffer),
4534                        diff.original_buffer_snapshot(),
4535                    )
4536                    .next()
4537                else {
4538                    continue;
4539                };
4540                let hunk_start = excerpt.buffer.anchor_after(hunk.diff_base_byte_range.start);
4541                let start = Anchor::in_buffer(excerpt.id, hunk_start).to_point(self);
4542                return Some(MultiBufferRow(start.row));
4543            } else {
4544                let Some(hunk) = diff
4545                    .hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer)
4546                    .next()
4547                else {
4548                    continue;
4549                };
4550                let start = Anchor::in_buffer(excerpt.id, hunk.buffer_range.start).to_point(self);
4551                return Some(MultiBufferRow(start.row));
4552            }
4553        }
4554    }
4555
4556    pub fn has_diff_hunks(&self) -> bool {
4557        self.diffs.values().any(|diff| !diff.is_empty())
4558    }
4559
4560    pub fn is_inside_word<T: ToOffset>(
4561        &self,
4562        position: T,
4563        scope_context: Option<CharScopeContext>,
4564    ) -> bool {
4565        let position = position.to_offset(self);
4566        let classifier = self
4567            .char_classifier_at(position)
4568            .scope_context(scope_context);
4569        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4570        let prev_char_kind = self
4571            .reversed_chars_at(position)
4572            .next()
4573            .map(|c| classifier.kind(c));
4574        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4575    }
4576
4577    pub fn surrounding_word<T: ToOffset>(
4578        &self,
4579        start: T,
4580        scope_context: Option<CharScopeContext>,
4581    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4582        let mut start = start.to_offset(self);
4583        let mut end = start;
4584        let mut next_chars = self.chars_at(start).peekable();
4585        let mut prev_chars = self.reversed_chars_at(start).peekable();
4586
4587        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4588
4589        let word_kind = cmp::max(
4590            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4591            next_chars.peek().copied().map(|c| classifier.kind(c)),
4592        );
4593
4594        for ch in prev_chars {
4595            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4596                start -= ch.len_utf8();
4597            } else {
4598                break;
4599            }
4600        }
4601
4602        for ch in next_chars {
4603            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4604                end += ch.len_utf8();
4605            } else {
4606                break;
4607            }
4608        }
4609
4610        (start..end, word_kind)
4611    }
4612
4613    pub fn char_kind_before<T: ToOffset>(
4614        &self,
4615        start: T,
4616        scope_context: Option<CharScopeContext>,
4617    ) -> Option<CharKind> {
4618        let start = start.to_offset(self);
4619        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4620        self.reversed_chars_at(start)
4621            .next()
4622            .map(|ch| classifier.kind(ch))
4623    }
4624
4625    pub fn is_singleton(&self) -> bool {
4626        self.singleton
4627    }
4628
4629    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4630        if self.singleton {
4631            self.excerpts
4632                .iter()
4633                .next()
4634                .map(|e| (&e.id, e.buffer_id, &*e.buffer))
4635        } else {
4636            None
4637        }
4638    }
4639
4640    pub fn len(&self) -> MultiBufferOffset {
4641        self.diff_transforms.summary().output.len
4642    }
4643
4644    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4645        MBD::from_summary(&self.text_summary())
4646    }
4647
4648    pub fn is_empty(&self) -> bool {
4649        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4650    }
4651
4652    pub fn widest_line_number(&self) -> u32 {
4653        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4654        self.excerpts.summary().widest_line_number + 1
4655    }
4656
4657    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4658        let range = range.start.to_offset(self)..range.end.to_offset(self);
4659        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4660        excerpts.seek(&range.start);
4661
4662        let mut chunk;
4663        let mut has_trailing_newline;
4664        let excerpt_bytes;
4665        if let Some(region) = excerpts.region() {
4666            let mut bytes = region.buffer.bytes_in_range(
4667                region.buffer_range.start + (range.start - region.range.start)
4668                    ..(region.buffer_range.start + (range.end - region.range.start))
4669                        .min(region.buffer_range.end),
4670            );
4671            chunk = bytes.next().unwrap_or(&[][..]);
4672            excerpt_bytes = Some(bytes);
4673            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4674            if chunk.is_empty() && has_trailing_newline {
4675                chunk = b"\n";
4676                has_trailing_newline = false;
4677            }
4678        } else {
4679            chunk = &[][..];
4680            excerpt_bytes = None;
4681            has_trailing_newline = false;
4682        };
4683
4684        MultiBufferBytes {
4685            range,
4686            cursor: excerpts,
4687            excerpt_bytes,
4688            has_trailing_newline,
4689            chunk,
4690        }
4691    }
4692
4693    pub fn reversed_bytes_in_range<T: ToOffset>(
4694        &self,
4695        range: Range<T>,
4696    ) -> ReversedMultiBufferBytes<'_> {
4697        let range = range.start.to_offset(self)..range.end.to_offset(self);
4698        let mut chunks = self.reversed_chunks_in_range(range.clone());
4699        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4700        ReversedMultiBufferBytes {
4701            range,
4702            chunks,
4703            chunk,
4704        }
4705    }
4706
4707    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4708        let mut cursor = self.cursor::<Point, Point>();
4709        cursor.seek(&Point::new(start_row.0, 0));
4710        let mut result = MultiBufferRows {
4711            point: Point::new(0, 0),
4712            is_empty: self.excerpts.is_empty(),
4713            is_singleton: self.is_singleton(),
4714            cursor,
4715        };
4716        result.seek(start_row);
4717        result
4718    }
4719
4720    pub fn chunks<T: ToOffset>(
4721        &self,
4722        range: Range<T>,
4723        language_aware: bool,
4724    ) -> MultiBufferChunks<'_> {
4725        let mut chunks = MultiBufferChunks {
4726            excerpt_offset_range: ExcerptDimension(MultiBufferOffset::ZERO)
4727                ..ExcerptDimension(MultiBufferOffset::ZERO),
4728            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4729            excerpts: self.excerpts.cursor(()),
4730            diff_transforms: self.diff_transforms.cursor(()),
4731            diffs: &self.diffs,
4732            diff_base_chunks: None,
4733            excerpt_chunks: None,
4734            buffer_chunk: None,
4735            language_aware,
4736        };
4737        let range = range.start.to_offset(self)..range.end.to_offset(self);
4738        chunks.seek(range);
4739        chunks
4740    }
4741
4742    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4743        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4744    }
4745
4746    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4747        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4748    }
4749
4750    pub fn clip_offset_utf16(
4751        &self,
4752        offset: MultiBufferOffsetUtf16,
4753        bias: Bias,
4754    ) -> MultiBufferOffsetUtf16 {
4755        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4756    }
4757
4758    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4759        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4760            buffer.clip_point_utf16(Unclipped(point), bias)
4761        })
4762    }
4763
4764    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4765        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4766    }
4767
4768    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4769        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4770    }
4771
4772    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4773        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4774    }
4775
4776    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4777        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4778    }
4779
4780    #[instrument(skip_all)]
4781    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4782        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4783    }
4784
4785    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4786        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4787    }
4788
4789    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4790        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4791    }
4792
4793    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4794        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4795    }
4796
4797    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4798        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4799    }
4800
4801    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4802        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4803    }
4804
4805    fn clip_dimension<MBD, BD>(
4806        &self,
4807        position: MBD,
4808        bias: Bias,
4809        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4810    ) -> MBD
4811    where
4812        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4813        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4814    {
4815        let mut cursor = self.cursor::<MBD, BD>();
4816        cursor.seek(&position);
4817        if let Some(region) = cursor.region() {
4818            if position >= region.range.end {
4819                return region.range.end;
4820            }
4821            let overshoot = position - region.range.start;
4822            let mut buffer_position = region.buffer_range.start;
4823            buffer_position += overshoot;
4824            let clipped_buffer_position =
4825                clip_buffer_position(region.buffer, buffer_position, bias);
4826            let mut position = region.range.start;
4827            position += clipped_buffer_position - region.buffer_range.start;
4828            position
4829        } else {
4830            self.max_position()
4831        }
4832    }
4833
4834    #[instrument(skip_all)]
4835    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4836        &self,
4837        key: MBR1,
4838        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4839    ) -> MBR2
4840    where
4841        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4842        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4843        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4844        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4845    {
4846        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4847        cursor.seek(&DimensionPair { key, value: None });
4848        if let Some(region) = cursor.region() {
4849            if key >= region.range.end.key {
4850                return region.range.end.value.unwrap();
4851            }
4852            let start_key = region.range.start.key;
4853            let start_value = region.range.start.value.unwrap();
4854            let buffer_start_key = region.buffer_range.start.key;
4855            let buffer_start_value = region.buffer_range.start.value.unwrap();
4856            let mut buffer_key = buffer_start_key;
4857            buffer_key += key - start_key;
4858            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4859            let mut result = start_value;
4860            result += buffer_value - buffer_start_value;
4861            result
4862        } else {
4863            self.max_position()
4864        }
4865    }
4866
4867    pub fn point_to_buffer_offset<T: ToOffset>(
4868        &self,
4869        point: T,
4870    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4871        let offset = point.to_offset(self);
4872        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4873        cursor.seek(&offset);
4874        let region = cursor.region()?;
4875        let overshoot = offset - region.range.start;
4876        let buffer_offset = region.buffer_range.start + overshoot;
4877        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4878            && region.has_trailing_newline
4879            && !region.is_main_buffer
4880        {
4881            let main_buffer_position = cursor.main_buffer_position()?;
4882            let buffer_snapshot = &cursor.excerpt()?.buffer;
4883            return Some((buffer_snapshot, main_buffer_position));
4884        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4885            return None;
4886        }
4887        Some((region.buffer, buffer_offset))
4888    }
4889
4890    pub fn point_to_buffer_point(
4891        &self,
4892        point: Point,
4893    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4894        let mut cursor = self.cursor::<Point, Point>();
4895        cursor.seek(&point);
4896        let region = cursor.region()?;
4897        let overshoot = point - region.range.start;
4898        let buffer_point = region.buffer_range.start + overshoot;
4899        let excerpt = cursor.excerpt()?;
4900        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4901            && region.has_trailing_newline
4902            && !region.is_main_buffer
4903        {
4904            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4905        } else if buffer_point > region.buffer.max_point() {
4906            return None;
4907        }
4908        Some((region.buffer, buffer_point, excerpt.id))
4909    }
4910
4911    pub fn suggested_indents(
4912        &self,
4913        rows: impl IntoIterator<Item = u32>,
4914        cx: &App,
4915    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4916        let mut result = BTreeMap::new();
4917        self.suggested_indents_callback(
4918            rows,
4919            |row, indent| {
4920                result.insert(row, indent);
4921                ControlFlow::Continue(())
4922            },
4923            cx,
4924        );
4925        result
4926    }
4927
4928    // move this to be a generator once those are a thing
4929    pub fn suggested_indents_callback(
4930        &self,
4931        rows: impl IntoIterator<Item = u32>,
4932        mut cb: impl FnMut(MultiBufferRow, IndentSize) -> ControlFlow<()>,
4933        cx: &App,
4934    ) {
4935        let mut rows_for_excerpt = Vec::new();
4936        let mut cursor = self.cursor::<Point, Point>();
4937        let mut rows = rows.into_iter().peekable();
4938        let mut prev_row = u32::MAX;
4939        let mut prev_language_indent_size = IndentSize::default();
4940
4941        while let Some(row) = rows.next() {
4942            cursor.seek(&Point::new(row, 0));
4943            let Some(region) = cursor.region() else {
4944                continue;
4945            };
4946
4947            // Retrieve the language and indent size once for each disjoint region being indented.
4948            let single_indent_size = if row.saturating_sub(1) == prev_row {
4949                prev_language_indent_size
4950            } else {
4951                region
4952                    .buffer
4953                    .language_indent_size_at(Point::new(row, 0), cx)
4954            };
4955            prev_language_indent_size = single_indent_size;
4956            prev_row = row;
4957
4958            let start_buffer_row = region.buffer_range.start.row;
4959            let start_multibuffer_row = region.range.start.row;
4960            let end_multibuffer_row = region.range.end.row;
4961
4962            rows_for_excerpt.push(row);
4963            while let Some(next_row) = rows.peek().copied() {
4964                if end_multibuffer_row > next_row {
4965                    rows_for_excerpt.push(next_row);
4966                    rows.next();
4967                } else {
4968                    break;
4969                }
4970            }
4971
4972            let buffer_rows = rows_for_excerpt
4973                .drain(..)
4974                .map(|row| start_buffer_row + row - start_multibuffer_row);
4975            let buffer_indents = region
4976                .buffer
4977                .suggested_indents(buffer_rows, single_indent_size);
4978            for (row, indent) in buffer_indents {
4979                if cb(
4980                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4981                    indent,
4982                )
4983                .is_break()
4984                {
4985                    return;
4986                }
4987            }
4988        }
4989    }
4990
4991    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4992        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4993            let mut size = buffer.indent_size_for_line(range.start.row);
4994            size.len = size
4995                .len
4996                .min(range.end.column)
4997                .saturating_sub(range.start.column);
4998            size
4999        } else {
5000            IndentSize::spaces(0)
5001        }
5002    }
5003
5004    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
5005        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
5006            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
5007        } else {
5008            LineIndent::spaces(0)
5009        }
5010    }
5011
5012    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
5013        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
5014
5015        if self.language_settings(cx).extend_comment_on_newline
5016            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
5017        {
5018            let delimiters = language_scope.line_comment_prefixes();
5019            for delimiter in delimiters {
5020                if *self
5021                    .chars_at(Point::new(row.0, indent.len() as u32))
5022                    .take(delimiter.chars().count())
5023                    .collect::<String>()
5024                    .as_str()
5025                    == **delimiter
5026                {
5027                    indent.push_str(delimiter);
5028                    break;
5029                }
5030            }
5031        }
5032
5033        indent
5034    }
5035
5036    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
5037    where
5038        T: ToOffset,
5039    {
5040        for char in self.reversed_chars_at(position) {
5041            if !char.is_whitespace() {
5042                return false;
5043            }
5044            if char == '\n' {
5045                return true;
5046            }
5047        }
5048        true
5049    }
5050
5051    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
5052        while row.0 > 0 {
5053            row.0 -= 1;
5054            if !self.is_line_blank(row) {
5055                return Some(row);
5056            }
5057        }
5058        None
5059    }
5060
5061    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
5062        if let Some((_, range)) = self.buffer_line_for_row(row) {
5063            range.end.column - range.start.column
5064        } else {
5065            0
5066        }
5067    }
5068
5069    pub fn buffer_line_for_row(
5070        &self,
5071        row: MultiBufferRow,
5072    ) -> Option<(&BufferSnapshot, Range<Point>)> {
5073        let mut cursor = self.cursor::<Point, Point>();
5074        let point = Point::new(row.0, 0);
5075        cursor.seek(&point);
5076        let region = cursor.region()?;
5077        let overshoot = point.min(region.range.end) - region.range.start;
5078        let buffer_point = region.buffer_range.start + overshoot;
5079        if buffer_point.row > region.buffer_range.end.row {
5080            return None;
5081        }
5082        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
5083        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
5084            .min(region.buffer_range.end);
5085        Some((region.buffer, line_start..line_end))
5086    }
5087
5088    pub fn max_point(&self) -> Point {
5089        self.text_summary().lines
5090    }
5091
5092    pub fn max_row(&self) -> MultiBufferRow {
5093        MultiBufferRow(self.text_summary().lines.row)
5094    }
5095
5096    pub fn text_summary(&self) -> MBTextSummary {
5097        self.diff_transforms.summary().output
5098    }
5099
5100    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
5101    where
5102        MBD: MultiBufferDimension + AddAssign,
5103        O: ToOffset,
5104    {
5105        let range = range.start.to_offset(self)..range.end.to_offset(self);
5106        let mut cursor = self
5107            .diff_transforms
5108            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5109        cursor.seek(&range.start, Bias::Right);
5110
5111        let Some(first_transform) = cursor.item() else {
5112            return MBD::from_summary(&MBTextSummary::default());
5113        };
5114
5115        let diff_transform_start = cursor.start().0;
5116        let diff_transform_end = cursor.end().0;
5117        let diff_start = range.start;
5118        let start_overshoot = diff_start - diff_transform_start;
5119        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
5120
5121        let mut result = match first_transform {
5122            DiffTransform::BufferContent { .. } => {
5123                let excerpt_start = cursor.start().1 + start_overshoot;
5124                let excerpt_end = cursor.start().1 + end_overshoot;
5125                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
5126            }
5127            DiffTransform::DeletedHunk {
5128                buffer_id,
5129                base_text_byte_range,
5130                has_trailing_newline,
5131                ..
5132            } => {
5133                let buffer_start = base_text_byte_range.start + start_overshoot;
5134                let mut buffer_end = base_text_byte_range.start + end_overshoot;
5135                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5136                    panic!("{:?} is in non-existent deleted hunk", range.start)
5137                };
5138
5139                let include_trailing_newline =
5140                    *has_trailing_newline && range.end >= diff_transform_end;
5141                if include_trailing_newline {
5142                    buffer_end -= 1;
5143                }
5144
5145                let mut summary = base_text
5146                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
5147
5148                if include_trailing_newline {
5149                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
5150                        &TextSummary::newline(),
5151                    ))
5152                }
5153
5154                let mut result = MBD::default();
5155                result.add_text_dim(&summary);
5156                result
5157            }
5158        };
5159        if range.end < diff_transform_end {
5160            return result;
5161        }
5162
5163        cursor.next();
5164        result.add_mb_text_summary(
5165            &cursor
5166                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
5167                .0,
5168        );
5169
5170        let Some(last_transform) = cursor.item() else {
5171            return result;
5172        };
5173
5174        let overshoot = range.end - cursor.start().0;
5175        let suffix = match last_transform {
5176            DiffTransform::BufferContent { .. } => {
5177                let end = cursor.start().1 + overshoot;
5178                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
5179            }
5180            DiffTransform::DeletedHunk {
5181                base_text_byte_range,
5182                buffer_id,
5183                has_trailing_newline,
5184                ..
5185            } => {
5186                let buffer_end = base_text_byte_range.start + overshoot;
5187                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
5188                    panic!("{:?} is in non-existent deleted hunk", range.end)
5189                };
5190
5191                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
5192                    base_text_byte_range.start..buffer_end,
5193                );
5194                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
5195                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
5196                        &TextSummary::from("\n"),
5197                    ))
5198                }
5199
5200                let mut result = MBD::default();
5201                result.add_text_dim(&suffix);
5202                result
5203            }
5204        };
5205
5206        result += suffix;
5207        result
5208    }
5209
5210    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
5211    where
5212        MBD: MultiBufferDimension + AddAssign,
5213    {
5214        let mut summary = MBD::default();
5215        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
5216        cursor.seek(&range.start, Bias::Right);
5217        if let Some(excerpt) = cursor.item() {
5218            let mut end_before_newline = cursor.end();
5219            if excerpt.has_trailing_newline {
5220                end_before_newline -= 1;
5221            }
5222
5223            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5224            let start_in_excerpt = excerpt_start + (range.start - *cursor.start());
5225            let end_in_excerpt =
5226                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start());
5227            summary.add_text_dim(
5228                &excerpt
5229                    .buffer
5230                    .text_summary_for_range::<MBD::TextDimension, _>(
5231                        start_in_excerpt..end_in_excerpt,
5232                    ),
5233            );
5234
5235            if range.end > end_before_newline {
5236                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5237            }
5238
5239            cursor.next();
5240        }
5241
5242        if range.end > *cursor.start() {
5243            summary += cursor
5244                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
5245                .0;
5246            if let Some(excerpt) = cursor.item() {
5247                range.end = cmp::max(*cursor.start(), range.end);
5248
5249                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5250                let end_in_excerpt = excerpt_start + (range.end - *cursor.start());
5251                summary.add_text_dim(
5252                    &excerpt
5253                        .buffer
5254                        .text_summary_for_range::<MBD::TextDimension, _>(
5255                            excerpt_start..end_in_excerpt,
5256                        ),
5257                );
5258            }
5259        }
5260
5261        summary
5262    }
5263
5264    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
5265    where
5266        MBD: MultiBufferDimension
5267            + Ord
5268            + Sub<Output = MBD::TextDimension>
5269            + Sub<MBD::TextDimension, Output = MBD>
5270            + AddAssign<MBD::TextDimension>
5271            + Add<MBD::TextDimension, Output = MBD>,
5272        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5273    {
5274        let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5275        let locator = self.excerpt_locator_for_id(excerpt_id);
5276        let (start, _, mut item) = self
5277            .excerpts
5278            .find::<ExcerptSummary, _>((), locator, Bias::Left);
5279        let mut start = MBD::from_summary(&start.text);
5280        if item.is_none() && excerpt_id == ExcerptId::max() {
5281            item = self.excerpts.last();
5282            if let Some(last_summary) = self.excerpts.last_summary() {
5283                start = start - <MBD::TextDimension>::from_text_summary(&last_summary.text.into());
5284            }
5285        }
5286
5287        if self.diff_transforms.is_empty() {
5288            let excerpt_start_position = ExcerptDimension(start);
5289            if let Some(excerpt) = item {
5290                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5291                    return excerpt_start_position.0;
5292                }
5293                let excerpt_buffer_start = excerpt
5294                    .range
5295                    .context
5296                    .start
5297                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5298                let excerpt_buffer_end = excerpt
5299                    .range
5300                    .context
5301                    .end
5302                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5303                let buffer_summary = anchor
5304                    .text_anchor
5305                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5306                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5307                let mut position = excerpt_start_position;
5308                if summary > excerpt_buffer_start {
5309                    position += summary - excerpt_buffer_start;
5310                }
5311
5312                position.0
5313            } else {
5314                excerpt_start_position.0
5315            }
5316        } else {
5317            let mut diff_transforms_cursor = self
5318                .diff_transforms
5319                .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5320            diff_transforms_cursor.next();
5321
5322            let excerpt_start_position = ExcerptDimension(start);
5323            if let Some(excerpt) = item {
5324                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5325                    return self.resolve_summary_for_anchor(
5326                        &Anchor::min(),
5327                        excerpt_start_position,
5328                        &mut diff_transforms_cursor,
5329                    );
5330                }
5331                let excerpt_buffer_start = excerpt
5332                    .range
5333                    .context
5334                    .start
5335                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5336                let excerpt_buffer_end = excerpt
5337                    .range
5338                    .context
5339                    .end
5340                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5341                let buffer_summary = anchor
5342                    .text_anchor
5343                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5344                let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5345                let mut position = excerpt_start_position;
5346                if summary > excerpt_buffer_start {
5347                    position += summary - excerpt_buffer_start;
5348                }
5349
5350                if diff_transforms_cursor.start().0 < position {
5351                    diff_transforms_cursor.seek_forward(&position, Bias::Left);
5352                }
5353                self.resolve_summary_for_anchor(&anchor, position, &mut diff_transforms_cursor)
5354            } else {
5355                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5356                self.resolve_summary_for_anchor(
5357                    &Anchor::max(),
5358                    excerpt_start_position,
5359                    &mut diff_transforms_cursor,
5360                )
5361            }
5362        }
5363    }
5364
5365    fn resolve_summary_for_anchor<MBD>(
5366        &self,
5367        anchor: &Anchor,
5368        excerpt_position: ExcerptDimension<MBD>,
5369        diff_transforms: &mut Cursor<
5370            DiffTransform,
5371            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
5372        >,
5373    ) -> MBD
5374    where
5375        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
5376    {
5377        loop {
5378            let transform_end_position = diff_transforms.end().0;
5379            let at_transform_end =
5380                transform_end_position == excerpt_position && diff_transforms.item().is_some();
5381            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
5382                diff_transforms.next();
5383                continue;
5384            }
5385
5386            let mut position = diff_transforms.start().1;
5387            match diff_transforms.item() {
5388                Some(DiffTransform::DeletedHunk {
5389                    buffer_id,
5390                    base_text_byte_range,
5391                    ..
5392                }) => {
5393                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
5394                        && let Some(base_text) =
5395                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
5396                        && diff_base_anchor.is_valid(&base_text)
5397                    {
5398                        let base_text_offset = diff_base_anchor.to_offset(base_text);
5399                        if base_text_offset >= base_text_byte_range.start
5400                            && base_text_offset <= base_text_byte_range.end
5401                        {
5402                            let position_in_hunk = base_text
5403                                .text_summary_for_range::<MBD::TextDimension, _>(
5404                                    base_text_byte_range.start..base_text_offset,
5405                                );
5406                            position.0.add_text_dim(&position_in_hunk);
5407                        } else if at_transform_end {
5408                            diff_transforms.next();
5409                            continue;
5410                        }
5411                    }
5412                }
5413                _ => {
5414                    if at_transform_end && anchor.diff_base_anchor.is_some() {
5415                        diff_transforms.next();
5416                        continue;
5417                    }
5418                    let overshoot = excerpt_position - diff_transforms.start().0;
5419                    position += overshoot;
5420                }
5421            }
5422
5423            return position.0;
5424        }
5425    }
5426
5427    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
5428        let mut cursor = self
5429            .excerpts
5430            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5431        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
5432
5433        cursor.seek(&Some(locator), Bias::Left);
5434        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
5435            cursor.prev();
5436        }
5437
5438        let mut position = cursor.start().1;
5439        if let Some(excerpt) = cursor.item()
5440            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
5441        {
5442            let excerpt_buffer_start = excerpt
5443                .buffer
5444                .offset_for_anchor(&excerpt.range.context.start);
5445            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
5446            let buffer_position = cmp::min(
5447                excerpt_buffer_end,
5448                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
5449            );
5450            if buffer_position > excerpt_buffer_start {
5451                position += buffer_position - excerpt_buffer_start;
5452            }
5453        }
5454        position
5455    }
5456
5457    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
5458        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
5459            excerpt_id = *replacement;
5460        }
5461        excerpt_id
5462    }
5463
5464    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
5465    where
5466        MBD: MultiBufferDimension
5467            + Ord
5468            + Sub<Output = MBD::TextDimension>
5469            + AddAssign<MBD::TextDimension>,
5470        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
5471        I: 'a + IntoIterator<Item = &'a Anchor>,
5472    {
5473        let mut anchors = anchors.into_iter().peekable();
5474        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
5475        let mut diff_transforms_cursor = self
5476            .diff_transforms
5477            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
5478        diff_transforms_cursor.next();
5479
5480        let mut summaries = Vec::new();
5481        while let Some(anchor) = anchors.peek() {
5482            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
5483
5484            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
5485                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
5486            });
5487
5488            let locator = self.excerpt_locator_for_id(excerpt_id);
5489            cursor.seek_forward(locator, Bias::Left);
5490            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
5491                cursor.prev();
5492            }
5493
5494            let excerpt_start_position = ExcerptDimension(MBD::from_summary(&cursor.start().text));
5495            if let Some(excerpt) = cursor.item() {
5496                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
5497                    let position = self.resolve_summary_for_anchor(
5498                        &Anchor::min(),
5499                        excerpt_start_position,
5500                        &mut diff_transforms_cursor,
5501                    );
5502                    summaries.extend(excerpt_anchors.map(|_| position));
5503                    continue;
5504                }
5505                let excerpt_buffer_start = excerpt
5506                    .range
5507                    .context
5508                    .start
5509                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5510                let excerpt_buffer_end = excerpt
5511                    .range
5512                    .context
5513                    .end
5514                    .summary::<MBD::TextDimension>(&excerpt.buffer);
5515                for (buffer_summary, anchor) in excerpt
5516                    .buffer
5517                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
5518                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5519                    )
5520                {
5521                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5522                    let mut position = excerpt_start_position;
5523                    if summary > excerpt_buffer_start {
5524                        position += summary - excerpt_buffer_start;
5525                    }
5526
5527                    if diff_transforms_cursor.start().0 < position {
5528                        diff_transforms_cursor.seek_forward(&position, Bias::Left);
5529                    }
5530
5531                    summaries.push(self.resolve_summary_for_anchor(
5532                        anchor,
5533                        position,
5534                        &mut diff_transforms_cursor,
5535                    ));
5536                }
5537            } else {
5538                diff_transforms_cursor.seek_forward(&excerpt_start_position, Bias::Left);
5539                let position = self.resolve_summary_for_anchor(
5540                    &Anchor::max(),
5541                    excerpt_start_position,
5542                    &mut diff_transforms_cursor,
5543                );
5544                summaries.extend(excerpt_anchors.map(|_| position));
5545            }
5546        }
5547
5548        summaries
5549    }
5550
5551    pub fn dimensions_from_points<'a, MBD>(
5552        &'a self,
5553        points: impl 'a + IntoIterator<Item = Point>,
5554    ) -> impl 'a + Iterator<Item = MBD>
5555    where
5556        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
5557    {
5558        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
5559        cursor.seek(&DimensionPair {
5560            key: Point::default(),
5561            value: None,
5562        });
5563        let mut points = points.into_iter();
5564        iter::from_fn(move || {
5565            let point = points.next()?;
5566
5567            cursor.seek_forward(&DimensionPair {
5568                key: point,
5569                value: None,
5570            });
5571
5572            if let Some(region) = cursor.region() {
5573                let overshoot = point - region.range.start.key;
5574                let buffer_point = region.buffer_range.start + overshoot;
5575                let mut position = region.range.start.value.unwrap();
5576                position.add_text_dim(
5577                    &region
5578                        .buffer
5579                        .text_summary_for_range(region.buffer_range.start..buffer_point),
5580                );
5581                if point == region.range.end.key && region.has_trailing_newline {
5582                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
5583                }
5584                Some(position)
5585            } else {
5586                Some(MBD::from_summary(&self.text_summary()))
5587            }
5588        })
5589    }
5590
5591    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5592    where
5593        I: 'a + IntoIterator<Item = &'a Anchor>,
5594    {
5595        let mut anchors = anchors.into_iter().enumerate().peekable();
5596        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
5597        cursor.next();
5598
5599        let mut result = Vec::new();
5600
5601        while let Some((_, anchor)) = anchors.peek() {
5602            let old_excerpt_id = anchor.excerpt_id;
5603
5604            // Find the location where this anchor's excerpt should be.
5605            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5606            cursor.seek_forward(&Some(old_locator), Bias::Left);
5607
5608            let next_excerpt = cursor.item();
5609            let prev_excerpt = cursor.prev_item();
5610
5611            // Process all of the anchors for this excerpt.
5612            while let Some((anchor_ix, &anchor)) =
5613                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
5614            {
5615                let mut anchor = anchor;
5616
5617                // Leave min and max anchors unchanged if invalid or
5618                // if the old excerpt still exists at this location
5619                let mut kept_position = next_excerpt
5620                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5621                    || old_excerpt_id == ExcerptId::max()
5622                    || old_excerpt_id == ExcerptId::min();
5623
5624                // If the old excerpt no longer exists at this location, then attempt to
5625                // find an equivalent position for this anchor in an adjacent excerpt.
5626                if !kept_position {
5627                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5628                        if excerpt.contains(&anchor) {
5629                            anchor.excerpt_id = excerpt.id;
5630                            kept_position = true;
5631                            break;
5632                        }
5633                    }
5634                }
5635
5636                // If there's no adjacent excerpt that contains the anchor's position,
5637                // then report that the anchor has lost its position.
5638                if !kept_position {
5639                    anchor = if let Some(excerpt) = next_excerpt {
5640                        let mut text_anchor = excerpt
5641                            .range
5642                            .context
5643                            .start
5644                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5645                        if text_anchor
5646                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5647                            .is_gt()
5648                        {
5649                            text_anchor = excerpt.range.context.end;
5650                        }
5651                        Anchor::in_buffer(excerpt.id, text_anchor)
5652                    } else if let Some(excerpt) = prev_excerpt {
5653                        let mut text_anchor = excerpt
5654                            .range
5655                            .context
5656                            .end
5657                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5658                        if text_anchor
5659                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5660                            .is_lt()
5661                        {
5662                            text_anchor = excerpt.range.context.start;
5663                        }
5664                        Anchor::in_buffer(excerpt.id, text_anchor)
5665                    } else if anchor.text_anchor.bias == Bias::Left {
5666                        Anchor::min()
5667                    } else {
5668                        Anchor::max()
5669                    };
5670                }
5671
5672                result.push((anchor_ix, anchor, kept_position));
5673            }
5674        }
5675        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5676        result
5677    }
5678
5679    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5680        self.anchor_at(position, Bias::Left)
5681    }
5682
5683    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5684        self.anchor_at(position, Bias::Right)
5685    }
5686
5687    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5688        let offset = position.to_offset(self);
5689
5690        // Find the given position in the diff transforms. Determine the corresponding
5691        // offset in the excerpts, and whether the position is within a deleted hunk.
5692        let mut diff_transforms = self
5693            .diff_transforms
5694            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5695        diff_transforms.seek(&offset, Bias::Right);
5696
5697        if offset == diff_transforms.start().0
5698            && bias == Bias::Left
5699            && let Some(prev_item) = diff_transforms.prev_item()
5700            && let DiffTransform::DeletedHunk { .. } = prev_item
5701        {
5702            diff_transforms.prev();
5703        }
5704        let offset_in_transform = offset - diff_transforms.start().0;
5705        let mut excerpt_offset = diff_transforms.start().1;
5706        let mut diff_base_anchor = None;
5707        if let Some(DiffTransform::DeletedHunk {
5708            buffer_id,
5709            base_text_byte_range,
5710            has_trailing_newline,
5711            ..
5712        }) = diff_transforms.item()
5713        {
5714            let diff = self.diffs.get(buffer_id).expect("missing diff");
5715            if offset_in_transform > base_text_byte_range.len() {
5716                debug_assert!(*has_trailing_newline);
5717                bias = Bias::Right;
5718            } else {
5719                diff_base_anchor = Some(
5720                    diff.base_text()
5721                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5722                );
5723                bias = Bias::Left;
5724            }
5725        } else {
5726            excerpt_offset += MultiBufferOffset(offset_in_transform);
5727        };
5728
5729        let mut excerpts = self
5730            .excerpts
5731            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5732        excerpts.seek(&excerpt_offset, Bias::Right);
5733        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5734            excerpts.prev();
5735        }
5736        if let Some(excerpt) = excerpts.item() {
5737            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0);
5738            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5739                overshoot -= 1;
5740                bias = Bias::Right;
5741            }
5742
5743            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5744            let text_anchor =
5745                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5746            let anchor = Anchor::in_buffer(excerpt.id, text_anchor);
5747            match diff_base_anchor {
5748                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5749                None => anchor,
5750            }
5751        } else if excerpt_offset == ExcerptDimension(MultiBufferOffset::ZERO) && bias == Bias::Left
5752        {
5753            Anchor::min()
5754        } else {
5755            Anchor::max()
5756        }
5757    }
5758
5759    /// Wraps the [`text::Anchor`] in a [`crate::Anchor`] if this multi-buffer is a singleton.
5760    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5761        let (excerpt, buffer, _) = self.as_singleton()?;
5762        if text_anchor.buffer_id.is_none_or(|id| id == buffer) {
5763            Some(Anchor::in_buffer(*excerpt, text_anchor))
5764        } else {
5765            None
5766        }
5767    }
5768
5769    /// Returns an anchor for the given excerpt and text anchor,
5770    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5771    pub fn anchor_range_in_excerpt(
5772        &self,
5773        excerpt_id: ExcerptId,
5774        text_anchor: Range<text::Anchor>,
5775    ) -> Option<Range<Anchor>> {
5776        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5777
5778        Some(
5779            Self::anchor_in_excerpt_(excerpt, text_anchor.start)?
5780                ..Self::anchor_in_excerpt_(excerpt, text_anchor.end)?,
5781        )
5782    }
5783
5784    /// Returns an anchor for the given excerpt and text anchor,
5785    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5786    pub fn anchor_in_excerpt(
5787        &self,
5788        excerpt_id: ExcerptId,
5789        text_anchor: text::Anchor,
5790    ) -> Option<Anchor> {
5791        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5792        Self::anchor_in_excerpt_(excerpt, text_anchor)
5793    }
5794
5795    /// Same as [`MultiBuffer::anchor_in_excerpt`], but more efficient than calling it multiple times.
5796    pub fn anchors_in_excerpt(
5797        &self,
5798        excerpt_id: ExcerptId,
5799        text_anchors: impl IntoIterator<Item = text::Anchor>,
5800    ) -> Option<impl Iterator<Item = Option<Anchor>>> {
5801        let excerpt = self.excerpt(self.latest_excerpt_id(excerpt_id))?;
5802        Some(
5803            text_anchors
5804                .into_iter()
5805                .map(|text_anchor| Self::anchor_in_excerpt_(excerpt, text_anchor)),
5806        )
5807    }
5808
5809    fn anchor_in_excerpt_(excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5810        match text_anchor.buffer_id {
5811            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5812            Some(_) => return None,
5813            None if text_anchor.is_max() || text_anchor.is_min() => {
5814                return Some(Anchor::in_buffer(excerpt.id, text_anchor));
5815            }
5816            None => return None,
5817        }
5818
5819        let context = &excerpt.range.context;
5820        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5821            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5822        {
5823            return None;
5824        }
5825
5826        Some(Anchor::in_buffer(excerpt.id, text_anchor))
5827    }
5828
5829    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5830        Some(self.excerpt(excerpt_id)?.range.context.clone())
5831    }
5832
5833    pub fn excerpt_range_for_excerpt(
5834        &self,
5835        excerpt_id: ExcerptId,
5836    ) -> Option<ExcerptRange<text::Anchor>> {
5837        Some(self.excerpt(excerpt_id)?.range.clone())
5838    }
5839
5840    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5841        if anchor.is_min() || anchor.is_max() {
5842            // todo(lw): should be `!self.is_empty()`
5843            true
5844        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5845            excerpt.buffer.can_resolve(&anchor.text_anchor)
5846        } else {
5847            false
5848        }
5849    }
5850
5851    pub fn excerpts(
5852        &self,
5853    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5854        self.excerpts
5855            .iter()
5856            .map(|excerpt| (excerpt.id, &*excerpt.buffer, excerpt.range.clone()))
5857    }
5858
5859    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5860    where
5861        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5862        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5863    {
5864        let excerpts = self.excerpts.cursor(());
5865        let diff_transforms = self.diff_transforms.cursor(());
5866        MultiBufferCursor {
5867            excerpts,
5868            diff_transforms,
5869            diffs: &self.diffs,
5870            cached_region: OnceCell::new(),
5871        }
5872    }
5873
5874    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5875        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5876        let mut excerpts = self
5877            .excerpts
5878            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
5879        excerpts.seek(&Some(start_locator), Bias::Left);
5880        excerpts.prev();
5881
5882        let mut diff_transforms = self
5883            .diff_transforms
5884            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5885        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5886        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5887            diff_transforms.next();
5888        }
5889
5890        let excerpt = excerpts.item()?;
5891        Some(MultiBufferExcerpt {
5892            excerpt,
5893            offset: diff_transforms.start().output_dimension.0,
5894            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5895            excerpt_offset: excerpts.start().1,
5896            diff_transforms,
5897        })
5898    }
5899
5900    pub fn excerpt_boundaries_in_range<R, T>(
5901        &self,
5902        range: R,
5903    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5904    where
5905        R: RangeBounds<T>,
5906        T: ToOffset,
5907    {
5908        let start_offset;
5909        let start = match range.start_bound() {
5910            Bound::Included(start) => {
5911                start_offset = start.to_offset(self);
5912                Bound::Included(start_offset)
5913            }
5914            Bound::Excluded(_) => {
5915                panic!("not supported")
5916            }
5917            Bound::Unbounded => {
5918                start_offset = MultiBufferOffset::ZERO;
5919                Bound::Unbounded
5920            }
5921        };
5922        let end = match range.end_bound() {
5923            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5924            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5925            Bound::Unbounded => Bound::Unbounded,
5926        };
5927        let bounds = (start, end);
5928        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5929        cursor.seek(&DimensionPair {
5930            key: start_offset,
5931            value: None,
5932        });
5933
5934        if cursor
5935            .fetch_excerpt_with_range()
5936            .is_some_and(|(_, range)| bounds.contains(&range.start.key))
5937        {
5938            cursor.prev_excerpt();
5939        } else {
5940            cursor.seek_to_start_of_current_excerpt();
5941        }
5942        let mut prev_region = cursor
5943            .fetch_excerpt_with_range()
5944            .map(|(excerpt, _)| excerpt);
5945
5946        cursor.next_excerpt_forwards();
5947
5948        iter::from_fn(move || {
5949            loop {
5950                if self.singleton {
5951                    return None;
5952                }
5953
5954                let (next_excerpt, next_range) = cursor.fetch_excerpt_with_range()?;
5955                cursor.next_excerpt_forwards();
5956                if !bounds.contains(&next_range.start.key) {
5957                    prev_region = Some(next_excerpt);
5958                    continue;
5959                }
5960
5961                let next_region_start = next_range.start.value.unwrap();
5962                let next_region_end = if let Some((_, range)) = cursor.fetch_excerpt_with_range() {
5963                    range.start.value.unwrap()
5964                } else {
5965                    self.max_point()
5966                };
5967
5968                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5969                    id: region.id,
5970                    buffer: region.buffer.clone(),
5971                    buffer_id: region.buffer_id,
5972                    range: region.range.clone(),
5973                    end_row: MultiBufferRow(next_region_start.row),
5974                });
5975
5976                let next = ExcerptInfo {
5977                    id: next_excerpt.id,
5978                    buffer: next_excerpt.buffer.clone(),
5979                    buffer_id: next_excerpt.buffer_id,
5980                    range: next_excerpt.range.clone(),
5981                    end_row: if next_excerpt.has_trailing_newline {
5982                        MultiBufferRow(next_region_end.row - 1)
5983                    } else {
5984                        MultiBufferRow(next_region_end.row)
5985                    },
5986                };
5987
5988                let row = MultiBufferRow(next_region_start.row);
5989
5990                prev_region = Some(next_excerpt);
5991
5992                return Some(ExcerptBoundary { row, prev, next });
5993            }
5994        })
5995    }
5996
5997    pub fn edit_count(&self) -> usize {
5998        self.edit_count
5999    }
6000
6001    pub fn non_text_state_update_count(&self) -> usize {
6002        self.non_text_state_update_count
6003    }
6004
6005    /// Returns the smallest enclosing bracket ranges containing the given range or
6006    /// None if no brackets contain range or the range is not contained in a single
6007    /// excerpt
6008    ///
6009    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
6010    #[ztracing::instrument(skip_all)]
6011    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
6012        &self,
6013        range: Range<T>,
6014        range_filter: Option<
6015            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
6016        >,
6017    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
6018        let range = range.start.to_offset(self)..range.end.to_offset(self);
6019        let mut excerpt = self.excerpt_containing(range.clone())?;
6020        let buffer = excerpt.buffer();
6021        let excerpt_buffer_range = excerpt.buffer_range();
6022
6023        // Filter to ranges contained in the excerpt
6024        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
6025            excerpt_buffer_range.contains(&BufferOffset(open.start))
6026                && excerpt_buffer_range.contains(&BufferOffset(close.end))
6027                && range_filter.is_none_or(|filter| {
6028                    filter(
6029                        buffer,
6030                        BufferOffset(open.start)..BufferOffset(close.end),
6031                        BufferOffset(close.start)..BufferOffset(close.end),
6032                    )
6033                })
6034        };
6035
6036        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
6037            excerpt.map_range_to_buffer(range),
6038            Some(&range_filter),
6039        )?;
6040
6041        Some((
6042            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
6043            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
6044        ))
6045    }
6046
6047    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6048    /// not contained in a single excerpt
6049    pub fn enclosing_bracket_ranges<T: ToOffset>(
6050        &self,
6051        range: Range<T>,
6052    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6053    {
6054        let range = range.start.to_offset(self)..range.end.to_offset(self);
6055        let mut excerpt = self.excerpt_containing(range.clone())?;
6056
6057        Some(
6058            excerpt
6059                .buffer()
6060                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
6061                .filter_map(move |pair| {
6062                    let open_range =
6063                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6064                    let close_range =
6065                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6066                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
6067                        Some((
6068                            excerpt.map_range_from_buffer(open_range),
6069                            excerpt.map_range_from_buffer(close_range),
6070                        ))
6071                    } else {
6072                        None
6073                    }
6074                }),
6075        )
6076    }
6077
6078    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
6079    /// not contained in a single excerpt
6080    pub fn text_object_ranges<T: ToOffset>(
6081        &self,
6082        range: Range<T>,
6083        options: TreeSitterOptions,
6084    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
6085        let range = range.start.to_offset(self)..range.end.to_offset(self);
6086        self.excerpt_containing(range.clone())
6087            .map(|mut excerpt| {
6088                excerpt
6089                    .buffer()
6090                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
6091                    .filter_map(move |(range, text_object)| {
6092                        let range = BufferOffset(range.start)..BufferOffset(range.end);
6093                        if excerpt.contains_buffer_range(range.clone()) {
6094                            Some((excerpt.map_range_from_buffer(range), text_object))
6095                        } else {
6096                            None
6097                        }
6098                    })
6099            })
6100            .into_iter()
6101            .flatten()
6102    }
6103
6104    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
6105    /// not contained in a single excerpt
6106    pub fn bracket_ranges<T: ToOffset>(
6107        &self,
6108        range: Range<T>,
6109    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
6110    {
6111        let range = range.start.to_offset(self)..range.end.to_offset(self);
6112        let mut excerpt = self.excerpt_containing(range.clone())?;
6113        Some(
6114            excerpt
6115                .buffer()
6116                .bracket_ranges(excerpt.map_range_to_buffer(range))
6117                .filter_map(move |pair| {
6118                    let open_range =
6119                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
6120                    let close_range =
6121                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
6122                    excerpt
6123                        .contains_buffer_range(open_range.start..close_range.end)
6124                        .then(|| BracketMatch {
6125                            open_range: excerpt.map_range_from_buffer(open_range),
6126                            close_range: excerpt.map_range_from_buffer(close_range),
6127                            color_index: pair.color_index,
6128                            newline_only: pair.newline_only,
6129                            syntax_layer_depth: pair.syntax_layer_depth,
6130                        })
6131                })
6132                .map(BracketMatch::bracket_ranges),
6133        )
6134    }
6135
6136    pub fn redacted_ranges<'a, T: ToOffset>(
6137        &'a self,
6138        range: Range<T>,
6139        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
6140    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
6141        let range = range.start.to_offset(self)..range.end.to_offset(self);
6142        self.lift_buffer_metadata(range, move |buffer, range| {
6143            if redaction_enabled(buffer.file()) {
6144                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
6145            } else {
6146                None
6147            }
6148        })
6149        .map(|(range, _, _)| range)
6150    }
6151
6152    pub fn runnable_ranges(
6153        &self,
6154        range: Range<Anchor>,
6155    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
6156        let range = range.start.to_offset(self)..range.end.to_offset(self);
6157        self.lift_buffer_metadata(range, move |buffer, range| {
6158            Some(
6159                buffer
6160                    .runnable_ranges(range.clone())
6161                    .filter(move |runnable| {
6162                        runnable.run_range.start >= range.start
6163                            && runnable.run_range.end < range.end
6164                    })
6165                    .map(|runnable| (runnable.run_range.clone(), runnable)),
6166            )
6167        })
6168        .map(|(run_range, runnable, _)| (run_range, runnable))
6169    }
6170
6171    pub fn line_indents(
6172        &self,
6173        start_row: MultiBufferRow,
6174        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6175    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6176        let max_point = self.max_point();
6177        let mut cursor = self.cursor::<Point, Point>();
6178        cursor.seek(&Point::new(start_row.0, 0));
6179        iter::from_fn(move || {
6180            let mut region = cursor.region()?;
6181            while !buffer_filter(&region.excerpt.buffer) {
6182                cursor.next();
6183                region = cursor.region()?;
6184            }
6185            let region = cursor.region()?;
6186            let overshoot = start_row.0.saturating_sub(region.range.start.row);
6187            let buffer_start_row =
6188                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
6189
6190            let buffer_end_row = if region.is_main_buffer
6191                && (region.has_trailing_newline || region.range.end == max_point)
6192            {
6193                region.buffer_range.end.row
6194            } else {
6195                region.buffer_range.end.row.saturating_sub(1)
6196            };
6197
6198            let line_indents = region
6199                .buffer
6200                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
6201            let region_buffer_row = region.buffer_range.start.row;
6202            let region_row = region.range.start.row;
6203            let region_buffer = &region.excerpt.buffer;
6204            cursor.next();
6205            Some(line_indents.map(move |(buffer_row, indent)| {
6206                let row = region_row + (buffer_row - region_buffer_row);
6207                (MultiBufferRow(row), indent, region_buffer.as_ref())
6208            }))
6209        })
6210        .flatten()
6211    }
6212
6213    pub fn reversed_line_indents(
6214        &self,
6215        end_row: MultiBufferRow,
6216        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
6217    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
6218        let max_point = self.max_point();
6219        let mut cursor = self.cursor::<Point, Point>();
6220        cursor.seek(&Point::new(end_row.0, 0));
6221        iter::from_fn(move || {
6222            let mut region = cursor.region()?;
6223            while !buffer_filter(&region.excerpt.buffer) {
6224                cursor.prev();
6225                region = cursor.region()?;
6226            }
6227            let region = cursor.region()?;
6228
6229            let buffer_start_row = region.buffer_range.start.row;
6230            let buffer_end_row = if region.is_main_buffer
6231                && (region.has_trailing_newline || region.range.end == max_point)
6232            {
6233                region.buffer_range.end.row + 1
6234            } else {
6235                region.buffer_range.end.row
6236            };
6237
6238            let overshoot = end_row.0 - region.range.start.row;
6239            let buffer_end_row =
6240                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
6241
6242            let line_indents = region
6243                .buffer
6244                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
6245            let region_buffer_row = region.buffer_range.start.row;
6246            let region_row = region.range.start.row;
6247            let region_buffer = &region.excerpt.buffer;
6248            cursor.prev();
6249            Some(line_indents.map(move |(buffer_row, indent)| {
6250                let row = region_row + (buffer_row - region_buffer_row);
6251                (MultiBufferRow(row), indent, region_buffer.as_ref())
6252            }))
6253        })
6254        .flatten()
6255    }
6256
6257    pub async fn enclosing_indent(
6258        &self,
6259        mut target_row: MultiBufferRow,
6260    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
6261        let max_row = MultiBufferRow(self.max_point().row);
6262        if target_row >= max_row {
6263            return None;
6264        }
6265
6266        let mut target_indent = self.line_indent_for_row(target_row);
6267
6268        // If the current row is at the start of an indented block, we want to return this
6269        // block as the enclosing indent.
6270        if !target_indent.is_line_empty() && target_row < max_row {
6271            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
6272            if !next_line_indent.is_line_empty()
6273                && target_indent.raw_len() < next_line_indent.raw_len()
6274            {
6275                target_indent = next_line_indent;
6276                target_row.0 += 1;
6277            }
6278        }
6279
6280        const SEARCH_ROW_LIMIT: u32 = 25000;
6281        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
6282        const YIELD_INTERVAL: u32 = 100;
6283
6284        let mut accessed_row_counter = 0;
6285
6286        // If there is a blank line at the current row, search for the next non indented lines
6287        if target_indent.is_line_empty() {
6288            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
6289            let end =
6290                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
6291
6292            let mut non_empty_line_above = None;
6293            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6294                if row < start {
6295                    break;
6296                }
6297                accessed_row_counter += 1;
6298                if accessed_row_counter == YIELD_INTERVAL {
6299                    accessed_row_counter = 0;
6300                    yield_now().await;
6301                }
6302                if !indent.is_line_empty() {
6303                    non_empty_line_above = Some((row, indent));
6304                    break;
6305                }
6306            }
6307
6308            let mut non_empty_line_below = None;
6309            for (row, indent, _) in self.line_indents(target_row, |_| true) {
6310                if row > end {
6311                    break;
6312                }
6313                accessed_row_counter += 1;
6314                if accessed_row_counter == YIELD_INTERVAL {
6315                    accessed_row_counter = 0;
6316                    yield_now().await;
6317                }
6318                if !indent.is_line_empty() {
6319                    non_empty_line_below = Some((row, indent));
6320                    break;
6321                }
6322            }
6323
6324            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
6325                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
6326                    if above_indent.raw_len() >= below_indent.raw_len() {
6327                        (above_row, above_indent)
6328                    } else {
6329                        (below_row, below_indent)
6330                    }
6331                }
6332                (Some(above), None) => above,
6333                (None, Some(below)) => below,
6334                _ => return None,
6335            };
6336
6337            target_indent = indent;
6338            target_row = row;
6339        }
6340
6341        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
6342        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
6343
6344        let mut start_indent = None;
6345        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
6346            if row < start {
6347                break;
6348            }
6349            accessed_row_counter += 1;
6350            if accessed_row_counter == YIELD_INTERVAL {
6351                accessed_row_counter = 0;
6352                yield_now().await;
6353            }
6354            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6355                start_indent = Some((row, indent));
6356                break;
6357            }
6358        }
6359        let (start_row, start_indent_size) = start_indent?;
6360
6361        let mut end_indent = (end, None);
6362        for (row, indent, _) in self.line_indents(target_row, |_| true) {
6363            if row > end {
6364                break;
6365            }
6366            accessed_row_counter += 1;
6367            if accessed_row_counter == YIELD_INTERVAL {
6368                accessed_row_counter = 0;
6369                yield_now().await;
6370            }
6371            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
6372                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
6373                break;
6374            }
6375        }
6376        let (end_row, end_indent_size) = end_indent;
6377
6378        let indent = if let Some(end_indent_size) = end_indent_size {
6379            if start_indent_size.raw_len() > end_indent_size.raw_len() {
6380                start_indent_size
6381            } else {
6382                end_indent_size
6383            }
6384        } else {
6385            start_indent_size
6386        };
6387
6388        Some((start_row..end_row, indent))
6389    }
6390
6391    pub fn indent_guides_in_range<T: ToPoint>(
6392        &self,
6393        range: Range<T>,
6394        ignore_disabled_for_language: bool,
6395        cx: &App,
6396    ) -> impl Iterator<Item = IndentGuide> {
6397        let range = range.start.to_point(self)..range.end.to_point(self);
6398        let start_row = MultiBufferRow(range.start.row);
6399        let end_row = MultiBufferRow(range.end.row);
6400
6401        let mut row_indents = self.line_indents(start_row, |buffer| {
6402            let settings =
6403                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
6404            settings.indent_guides.enabled || ignore_disabled_for_language
6405        });
6406
6407        let mut result = Vec::new();
6408        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
6409
6410        let mut prev_settings = None;
6411        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
6412            if first_row > end_row {
6413                break;
6414            }
6415            let current_depth = indent_stack.len() as u32;
6416
6417            // Avoid retrieving the language settings repeatedly for every buffer row.
6418            if let Some((prev_buffer_id, _)) = &prev_settings
6419                && prev_buffer_id != &buffer.remote_id()
6420            {
6421                prev_settings.take();
6422            }
6423            let settings = &prev_settings
6424                .get_or_insert_with(|| {
6425                    (
6426                        buffer.remote_id(),
6427                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
6428                    )
6429                })
6430                .1;
6431            let tab_size = settings.tab_size.get();
6432
6433            // When encountering empty, continue until found useful line indent
6434            // then add to the indent stack with the depth found
6435            let mut found_indent = false;
6436            let mut last_row = first_row;
6437            if line_indent.is_line_blank() {
6438                while !found_indent {
6439                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
6440                        break;
6441                    };
6442                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
6443                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
6444                        break;
6445                    }
6446
6447                    if new_line_indent.is_line_blank() {
6448                        continue;
6449                    }
6450                    last_row = target_row.min(end_row);
6451                    line_indent = new_line_indent;
6452                    found_indent = true;
6453                    break;
6454                }
6455            } else {
6456                found_indent = true
6457            }
6458
6459            let depth = if found_indent {
6460                line_indent.len(tab_size) / tab_size
6461            } else {
6462                0
6463            };
6464
6465            match depth.cmp(&current_depth) {
6466                cmp::Ordering::Less => {
6467                    for _ in 0..(current_depth - depth) {
6468                        let mut indent = indent_stack.pop().unwrap();
6469                        if last_row != first_row {
6470                            // In this case, we landed on an empty row, had to seek forward,
6471                            // and discovered that the indent we where on is ending.
6472                            // This means that the last display row must
6473                            // be on line that ends this indent range, so we
6474                            // should display the range up to the first non-empty line
6475                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
6476                        }
6477
6478                        result.push(indent)
6479                    }
6480                }
6481                cmp::Ordering::Greater => {
6482                    for next_depth in current_depth..depth {
6483                        indent_stack.push(IndentGuide {
6484                            buffer_id: buffer.remote_id(),
6485                            start_row: first_row,
6486                            end_row: last_row,
6487                            depth: next_depth,
6488                            tab_size,
6489                            settings: settings.indent_guides.clone(),
6490                        });
6491                    }
6492                }
6493                _ => {}
6494            }
6495
6496            for indent in indent_stack.iter_mut() {
6497                indent.end_row = last_row;
6498            }
6499        }
6500
6501        result.extend(indent_stack);
6502        result.into_iter()
6503    }
6504
6505    pub fn trailing_excerpt_update_count(&self) -> usize {
6506        self.trailing_excerpt_update_count
6507    }
6508
6509    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
6510        self.point_to_buffer_offset(point)
6511            .and_then(|(buffer, _)| buffer.file())
6512    }
6513
6514    pub fn language_at<T: ToOffset>(&self, offset: T) -> Option<&Arc<Language>> {
6515        self.point_to_buffer_offset(offset)
6516            .and_then(|(buffer, offset)| buffer.language_at(offset))
6517    }
6518
6519    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
6520        self.excerpts
6521            .first()
6522            .map(|excerpt| &excerpt.buffer)
6523            .map(|buffer| {
6524                language_settings(
6525                    buffer.language().map(|language| language.name()),
6526                    buffer.file(),
6527                    cx,
6528                )
6529            })
6530            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
6531    }
6532
6533    pub fn language_settings_at<'a, T: ToOffset>(
6534        &'a self,
6535        point: T,
6536        cx: &'a App,
6537    ) -> Cow<'a, LanguageSettings> {
6538        let mut language = None;
6539        let mut file = None;
6540        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
6541            language = buffer.language_at(offset);
6542            file = buffer.file();
6543        }
6544        language_settings(language.map(|l| l.name()), file, cx)
6545    }
6546
6547    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
6548        self.point_to_buffer_offset(point)
6549            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
6550    }
6551
6552    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
6553        self.point_to_buffer_offset(point)
6554            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
6555            .unwrap_or_default()
6556    }
6557
6558    pub fn language_indent_size_at<T: ToOffset>(
6559        &self,
6560        position: T,
6561        cx: &App,
6562    ) -> Option<IndentSize> {
6563        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
6564        Some(buffer_snapshot.language_indent_size_at(offset, cx))
6565    }
6566
6567    pub fn is_dirty(&self) -> bool {
6568        self.is_dirty
6569    }
6570
6571    pub fn has_deleted_file(&self) -> bool {
6572        self.has_deleted_file
6573    }
6574
6575    pub fn has_conflict(&self) -> bool {
6576        self.has_conflict
6577    }
6578
6579    pub fn has_diagnostics(&self) -> bool {
6580        self.excerpts
6581            .iter()
6582            .any(|excerpt| excerpt.buffer.has_diagnostics())
6583    }
6584
6585    pub fn diagnostic_group(
6586        &self,
6587        buffer_id: BufferId,
6588        group_id: usize,
6589    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
6590        self.lift_buffer_metadata::<Point, _, _>(
6591            Point::zero()..self.max_point(),
6592            move |buffer, range| {
6593                if buffer.remote_id() != buffer_id {
6594                    return None;
6595                };
6596                Some(
6597                    buffer
6598                        .diagnostics_in_range(range, false)
6599                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6600                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
6601                )
6602            },
6603        )
6604        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6605    }
6606
6607    pub fn diagnostics_in_range<'a, MBD>(
6608        &'a self,
6609        range: Range<MBD>,
6610    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
6611    where
6612        MBD::TextDimension: 'a
6613            + text::ToOffset
6614            + text::FromAnchor
6615            + Sub<Output = MBD::TextDimension>
6616            + fmt::Debug
6617            + ops::Add<Output = MBD::TextDimension>
6618            + ops::AddAssign
6619            + Ord,
6620        MBD: MultiBufferDimension
6621            + Ord
6622            + Sub<Output = MBD::TextDimension>
6623            + ops::Add<MBD::TextDimension, Output = MBD>
6624            + ops::AddAssign<MBD::TextDimension>
6625            + 'a,
6626    {
6627        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6628            Some(
6629                buffer
6630                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6631                    .map(|entry| (entry.range, entry.diagnostic)),
6632            )
6633        })
6634        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
6635    }
6636
6637    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
6638        &'a self,
6639        range: Range<MBD>,
6640    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
6641    where
6642        MBD: MultiBufferDimension
6643            + Ord
6644            + Sub<Output = MBD::TextDimension>
6645            + ops::Add<MBD::TextDimension, Output = MBD>
6646            + ops::AddAssign<MBD::TextDimension>,
6647        MBD::TextDimension: Sub<Output = MBD::TextDimension>
6648            + ops::Add<Output = MBD::TextDimension>
6649            + text::ToOffset
6650            + text::FromAnchor
6651            + AddAssign<MBD::TextDimension>
6652            + Ord,
6653    {
6654        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
6655            Some(
6656                buffer
6657                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6658                    .map(|entry| (entry.range, entry.diagnostic)),
6659            )
6660        })
6661        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
6662    }
6663
6664    pub fn syntax_ancestor<T: ToOffset>(
6665        &self,
6666        range: Range<T>,
6667    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
6668        let range = range.start.to_offset(self)..range.end.to_offset(self);
6669        let mut excerpt = self.excerpt_containing(range.clone())?;
6670        let node = excerpt
6671            .buffer()
6672            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6673        let node_range = node.byte_range();
6674        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
6675        if !excerpt.contains_buffer_range(node_range.clone()) {
6676            return None;
6677        };
6678        Some((node, excerpt.map_range_from_buffer(node_range)))
6679    }
6680
6681    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6682        let (excerpt_id, _, buffer) = self.as_singleton()?;
6683        let outline = buffer.outline(theme);
6684        Some(Outline::new(
6685            outline
6686                .items
6687                .into_iter()
6688                .flat_map(|item| {
6689                    Some(OutlineItem {
6690                        depth: item.depth,
6691                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
6692                        source_range_for_text: self
6693                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
6694                        text: item.text,
6695                        highlight_ranges: item.highlight_ranges,
6696                        name_ranges: item.name_ranges,
6697                        body_range: item.body_range.and_then(|body_range| {
6698                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
6699                        }),
6700                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6701                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
6702                        }),
6703                    })
6704                })
6705                .collect(),
6706        ))
6707    }
6708
6709    pub fn symbols_containing<T: ToOffset>(
6710        &self,
6711        offset: T,
6712        theme: Option<&SyntaxTheme>,
6713    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6714        let anchor = self.anchor_before(offset);
6715        let excerpt @ &Excerpt {
6716            id: excerpt_id,
6717            buffer_id,
6718            ref buffer,
6719            ..
6720        } = self.excerpt(anchor.excerpt_id)?;
6721        if cfg!(debug_assertions) {
6722            match anchor.text_anchor.buffer_id {
6723                // we clearly are hitting this according to sentry, but in what situations can this occur?
6724                Some(anchor_buffer_id) => {
6725                    assert_eq!(
6726                        anchor_buffer_id, buffer_id,
6727                        "anchor {anchor:?} does not match with resolved excerpt {excerpt:?}"
6728                    )
6729                }
6730                None => assert!(anchor.is_max()),
6731            }
6732        };
6733        Some((
6734            buffer_id,
6735            buffer
6736                .symbols_containing(anchor.text_anchor, theme)
6737                .into_iter()
6738                .flat_map(|item| {
6739                    Some(OutlineItem {
6740                        depth: item.depth,
6741                        source_range_for_text: Anchor::range_in_buffer(
6742                            excerpt_id,
6743                            item.source_range_for_text,
6744                        ),
6745                        range: Anchor::range_in_buffer(excerpt_id, item.range),
6746                        text: item.text,
6747                        highlight_ranges: item.highlight_ranges,
6748                        name_ranges: item.name_ranges,
6749                        body_range: item
6750                            .body_range
6751                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6752                        annotation_range: item
6753                            .annotation_range
6754                            .map(|body_range| Anchor::range_in_buffer(excerpt_id, body_range)),
6755                    })
6756                })
6757                .collect(),
6758        ))
6759    }
6760
6761    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6762        if id == ExcerptId::min() {
6763            Locator::min_ref()
6764        } else if id == ExcerptId::max() {
6765            Locator::max_ref()
6766        } else {
6767            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6768            if let Some(entry) = item
6769                && entry.id == id
6770            {
6771                return &entry.locator;
6772            }
6773            panic!("invalid excerpt id {id:?}")
6774        }
6775    }
6776
6777    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6778    fn excerpt_locators_for_ids(
6779        &self,
6780        ids: impl IntoIterator<Item = ExcerptId>,
6781    ) -> SmallVec<[Locator; 1]> {
6782        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6783        sorted_ids.sort_unstable();
6784        sorted_ids.dedup();
6785        let mut locators = SmallVec::new();
6786
6787        while sorted_ids.last() == Some(&ExcerptId::max()) {
6788            sorted_ids.pop();
6789            locators.push(Locator::max());
6790        }
6791
6792        let mut sorted_ids = sorted_ids.into_iter().peekable();
6793        locators.extend(
6794            sorted_ids
6795                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6796                .map(|_| Locator::min()),
6797        );
6798
6799        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6800        for id in sorted_ids {
6801            if cursor.seek_forward(&id, Bias::Left) {
6802                locators.push(cursor.item().unwrap().locator.clone());
6803            } else {
6804                panic!("invalid excerpt id {:?}", id);
6805            }
6806        }
6807
6808        locators.sort_unstable();
6809        locators
6810    }
6811
6812    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6813        Some(self.excerpt(excerpt_id)?.buffer_id)
6814    }
6815
6816    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6817        Some(&self.excerpt(excerpt_id)?.buffer)
6818    }
6819
6820    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6821        let mut cursor = self
6822            .excerpts
6823            .cursor::<Dimensions<Option<&Locator>, ExcerptPoint>>(());
6824        let locator = self.excerpt_locator_for_id(excerpt_id);
6825        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6826        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6827            sought_exact = true;
6828            cursor.prev();
6829        } else if excerpt_id == ExcerptId::min() {
6830            sought_exact = true;
6831        }
6832        if sought_exact {
6833            let start = cursor.start().1;
6834            let end = cursor.end().1;
6835            let mut diff_transforms = self
6836                .diff_transforms
6837                .cursor::<Dimensions<ExcerptPoint, OutputDimension<Point>>>(());
6838            diff_transforms.seek(&start, Bias::Left);
6839            let overshoot = start - diff_transforms.start().0;
6840            let start = diff_transforms.start().1 + overshoot;
6841            diff_transforms.seek(&end, Bias::Right);
6842            let overshoot = end - diff_transforms.start().0;
6843            let end = diff_transforms.start().1 + overshoot;
6844            Some(start.0..end.0)
6845        } else {
6846            None
6847        }
6848    }
6849
6850    /// Returns the excerpt for the given id. The returned excerpt is guaranteed
6851    /// to have the latest excerpt id for the one passed in and will also remap
6852    /// `ExcerptId::max()` to the corresponding excertp ID.
6853    ///
6854    /// Callers of this function should generally use the resulting excerpt's `id` field
6855    /// afterwards.
6856    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6857        let excerpt_id = self.latest_excerpt_id(excerpt_id);
6858        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6859        let locator = self.excerpt_locator_for_id(excerpt_id);
6860        cursor.seek(&Some(locator), Bias::Left);
6861        if let Some(excerpt) = cursor.item()
6862            && excerpt.id == excerpt_id
6863        {
6864            return Some(excerpt);
6865        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6866            cursor.prev();
6867            return cursor.item();
6868        }
6869        None
6870    }
6871
6872    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6873    pub fn excerpt_containing<T: ToOffset>(
6874        &self,
6875        range: Range<T>,
6876    ) -> Option<MultiBufferExcerpt<'_>> {
6877        let range = range.start.to_offset(self)..range.end.to_offset(self);
6878        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6879        cursor.seek(&range.start);
6880
6881        let start_excerpt = cursor.excerpt()?;
6882        if range.end != range.start {
6883            cursor.seek_forward(&range.end);
6884            if cursor.excerpt()?.id != start_excerpt.id {
6885                return None;
6886            }
6887        }
6888
6889        cursor.seek_to_start_of_current_excerpt();
6890        let region = cursor.region()?;
6891        let offset = region.range.start;
6892        let buffer_offset = start_excerpt.buffer_start_offset();
6893        let excerpt_offset = *cursor.excerpts.start();
6894        Some(MultiBufferExcerpt {
6895            diff_transforms: cursor.diff_transforms,
6896            excerpt: start_excerpt,
6897            offset,
6898            buffer_offset,
6899            excerpt_offset,
6900        })
6901    }
6902
6903    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6904        if let Some(id) = anchor.text_anchor.buffer_id {
6905            return Some(id);
6906        }
6907        let excerpt = self.excerpt_containing(anchor..anchor)?;
6908        Some(excerpt.buffer_id())
6909    }
6910
6911    pub fn selections_in_range<'a>(
6912        &'a self,
6913        range: &'a Range<Anchor>,
6914        include_local: bool,
6915    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6916        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6917        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6918        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6919        cursor.seek(start_locator, Bias::Left);
6920        cursor
6921            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6922            .flat_map(move |excerpt| {
6923                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6924                if excerpt.id == range.start.excerpt_id {
6925                    query_range.start = range.start.text_anchor;
6926                }
6927                if excerpt.id == range.end.excerpt_id {
6928                    query_range.end = range.end.text_anchor;
6929                }
6930
6931                excerpt
6932                    .buffer
6933                    .selections_in_range(query_range, include_local)
6934                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6935                        selections.map(move |selection| {
6936                            let mut start = Anchor::in_buffer(excerpt.id, selection.start);
6937                            let mut end = Anchor::in_buffer(excerpt.id, selection.end);
6938                            if range.start.cmp(&start, self).is_gt() {
6939                                start = range.start;
6940                            }
6941                            if range.end.cmp(&end, self).is_lt() {
6942                                end = range.end;
6943                            }
6944
6945                            (
6946                                replica_id,
6947                                line_mode,
6948                                cursor_shape,
6949                                Selection {
6950                                    id: selection.id,
6951                                    start,
6952                                    end,
6953                                    reversed: selection.reversed,
6954                                    goal: selection.goal,
6955                                },
6956                            )
6957                        })
6958                    })
6959            })
6960    }
6961
6962    pub fn show_headers(&self) -> bool {
6963        self.show_headers
6964    }
6965
6966    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6967        self.diffs.get(&buffer_id).map(|diff| &diff.diff)
6968    }
6969
6970    pub fn all_diff_hunks_expanded(&self) -> bool {
6971        self.all_diff_hunks_expanded
6972    }
6973
6974    /// Visually annotates a position or range with the `Debug` representation of a value. The
6975    /// callsite of this function is used as a key - previous annotations will be removed.
6976    #[cfg(debug_assertions)]
6977    #[track_caller]
6978    pub fn debug<V, R>(&self, ranges: &R, value: V)
6979    where
6980        R: debug::ToMultiBufferDebugRanges,
6981        V: std::fmt::Debug,
6982    {
6983        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6984    }
6985
6986    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6987    /// debug annotations with the same key will be removed. The key is also used to determine the
6988    /// annotation's color.
6989    #[cfg(debug_assertions)]
6990    #[track_caller]
6991    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6992    where
6993        K: std::hash::Hash + 'static,
6994        R: debug::ToMultiBufferDebugRanges,
6995        V: std::fmt::Debug,
6996    {
6997        let text_ranges = ranges
6998            .to_multi_buffer_debug_ranges(self)
6999            .into_iter()
7000            .flat_map(|range| {
7001                self.range_to_buffer_ranges(range.start..=range.end)
7002                    .into_iter()
7003                    .map(|(buffer, range, _excerpt_id)| {
7004                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
7005                    })
7006            })
7007            .collect();
7008        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
7009            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
7010        });
7011    }
7012
7013    fn excerpt_edits_for_diff_change(
7014        &self,
7015        buffer_state: &BufferState,
7016        diff_change_range: Range<usize>,
7017    ) -> Vec<Edit<ExcerptDimension<MultiBufferOffset>>> {
7018        let mut excerpt_edits = Vec::new();
7019        for locator in &buffer_state.excerpts {
7020            let mut cursor = self
7021                .excerpts
7022                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
7023            cursor.seek_forward(&Some(locator), Bias::Left);
7024            if let Some(excerpt) = cursor.item()
7025                && excerpt.locator == *locator
7026            {
7027                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
7028                if diff_change_range.end < excerpt_buffer_range.start
7029                    || diff_change_range.start > excerpt_buffer_range.end
7030                {
7031                    continue;
7032                }
7033                let excerpt_start = cursor.start().1;
7034                let excerpt_len = excerpt.text_summary.len;
7035                let diff_change_start_in_excerpt = diff_change_range
7036                    .start
7037                    .saturating_sub(excerpt_buffer_range.start);
7038                let diff_change_end_in_excerpt = diff_change_range
7039                    .end
7040                    .saturating_sub(excerpt_buffer_range.start);
7041                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
7042                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
7043                excerpt_edits.push(Edit {
7044                    old: edit_start..edit_end,
7045                    new: edit_start..edit_end,
7046                });
7047            }
7048        }
7049        excerpt_edits
7050    }
7051}
7052
7053#[cfg(any(test, feature = "test-support"))]
7054impl MultiBufferSnapshot {
7055    pub fn random_byte_range(
7056        &self,
7057        start_offset: MultiBufferOffset,
7058        rng: &mut impl rand::Rng,
7059    ) -> Range<MultiBufferOffset> {
7060        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
7061        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
7062        start..end
7063    }
7064
7065    #[cfg(any(test, feature = "test-support"))]
7066    fn check_invariants(&self) {
7067        let excerpts = self.excerpts.items(());
7068        let excerpt_ids = self.excerpt_ids.items(());
7069
7070        for (ix, excerpt) in excerpts.iter().enumerate() {
7071            if ix == 0 {
7072                if excerpt.locator <= Locator::min() {
7073                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
7074                }
7075            } else if excerpt.locator <= excerpts[ix - 1].locator {
7076                panic!("excerpts are out-of-order: {:?}", excerpts);
7077            }
7078        }
7079
7080        for (ix, entry) in excerpt_ids.iter().enumerate() {
7081            if ix == 0 {
7082                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
7083                    panic!("invalid first excerpt id {:?}", entry.id);
7084                }
7085            } else if entry.id <= excerpt_ids[ix - 1].id {
7086                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
7087            }
7088        }
7089
7090        if self.diff_transforms.summary().input != self.excerpts.summary().text {
7091            panic!(
7092                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
7093                self.excerpts.summary().text,
7094                self.diff_transforms.summary().input,
7095                self.diff_transforms.items(()),
7096            );
7097        }
7098
7099        let mut prev_transform: Option<&DiffTransform> = None;
7100        for item in self.diff_transforms.iter() {
7101            if let DiffTransform::BufferContent {
7102                summary,
7103                inserted_hunk_info,
7104            } = item
7105            {
7106                if let Some(DiffTransform::BufferContent {
7107                    inserted_hunk_info: prev_inserted_hunk_info,
7108                    ..
7109                }) = prev_transform
7110                    && *inserted_hunk_info == *prev_inserted_hunk_info
7111                {
7112                    panic!(
7113                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
7114                        self.diff_transforms.items(())
7115                    );
7116                }
7117                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
7118                    panic!("empty buffer content transform");
7119                }
7120            }
7121            prev_transform = Some(item);
7122        }
7123    }
7124}
7125
7126impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
7127where
7128    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
7129    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
7130{
7131    #[instrument(skip_all)]
7132    fn seek(&mut self, position: &MBD) {
7133        let position = OutputDimension(*position);
7134        self.cached_region.take();
7135        self.diff_transforms.seek(&position, Bias::Right);
7136        if self.diff_transforms.item().is_none()
7137            && self.diff_transforms.start().output_dimension == position
7138        {
7139            self.diff_transforms.prev();
7140        }
7141
7142        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7143        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7144            let overshoot = position - self.diff_transforms.start().output_dimension;
7145            excerpt_position += overshoot;
7146        }
7147
7148        self.excerpts.seek(&excerpt_position, Bias::Right);
7149        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7150            self.excerpts.prev();
7151        }
7152    }
7153
7154    fn seek_forward(&mut self, position: &MBD) {
7155        let position = OutputDimension(*position);
7156        self.cached_region.take();
7157        self.diff_transforms.seek_forward(&position, Bias::Right);
7158        if self.diff_transforms.item().is_none()
7159            && self.diff_transforms.start().output_dimension == position
7160        {
7161            self.diff_transforms.prev();
7162        }
7163
7164        let overshoot = position - self.diff_transforms.start().output_dimension;
7165        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
7166        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7167            excerpt_position += overshoot;
7168        }
7169
7170        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
7171        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
7172            self.excerpts.prev();
7173        }
7174    }
7175
7176    fn next_excerpt(&mut self) {
7177        self.excerpts.next();
7178        self.seek_to_start_of_current_excerpt();
7179    }
7180
7181    fn prev_excerpt(&mut self) {
7182        self.excerpts.prev();
7183        self.seek_to_start_of_current_excerpt();
7184    }
7185
7186    fn seek_to_start_of_current_excerpt(&mut self) {
7187        self.cached_region.take();
7188
7189        if self.diff_transforms.seek(self.excerpts.start(), Bias::Left)
7190            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7191            && self.diff_transforms.next_item().is_some()
7192        {
7193            self.diff_transforms.next();
7194        }
7195    }
7196
7197    fn next_excerpt_forwards(&mut self) {
7198        self.excerpts.next();
7199        self.seek_to_start_of_current_excerpt_forward();
7200    }
7201
7202    fn seek_to_start_of_current_excerpt_forward(&mut self) {
7203        self.cached_region.take();
7204
7205        if self
7206            .diff_transforms
7207            .seek_forward(self.excerpts.start(), Bias::Left)
7208            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7209            && self.diff_transforms.next_item().is_some()
7210        {
7211            self.diff_transforms.next();
7212        }
7213    }
7214
7215    fn next(&mut self) {
7216        self.cached_region.take();
7217        match self
7218            .diff_transforms
7219            .end()
7220            .excerpt_dimension
7221            .cmp(&self.excerpts.end())
7222        {
7223            cmp::Ordering::Less => self.diff_transforms.next(),
7224            cmp::Ordering::Greater => self.excerpts.next(),
7225            cmp::Ordering::Equal => {
7226                self.diff_transforms.next();
7227                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7228                    || self.diff_transforms.item().is_none()
7229                {
7230                    self.excerpts.next();
7231                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
7232                    self.diff_transforms.item()
7233                    && self
7234                        .excerpts
7235                        .item()
7236                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
7237                {
7238                    self.excerpts.next();
7239                }
7240            }
7241        }
7242    }
7243
7244    fn prev(&mut self) {
7245        self.cached_region.take();
7246        match self
7247            .diff_transforms
7248            .start()
7249            .excerpt_dimension
7250            .cmp(self.excerpts.start())
7251        {
7252            cmp::Ordering::Less => self.excerpts.prev(),
7253            cmp::Ordering::Greater => self.diff_transforms.prev(),
7254            cmp::Ordering::Equal => {
7255                self.diff_transforms.prev();
7256                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
7257                    || self.diff_transforms.item().is_none()
7258                {
7259                    self.excerpts.prev();
7260                }
7261            }
7262        }
7263    }
7264
7265    fn region(&self) -> Option<&MultiBufferRegion<'a, MBD, BD>> {
7266        self.cached_region
7267            .get_or_init(|| self.build_region())
7268            .as_ref()
7269    }
7270
7271    fn is_at_start_of_excerpt(&mut self) -> bool {
7272        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
7273            return false;
7274        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7275            return true;
7276        }
7277
7278        self.diff_transforms.prev();
7279        let prev_transform = self.diff_transforms.item();
7280        self.diff_transforms.next();
7281
7282        prev_transform.is_none_or(|next_transform| {
7283            matches!(next_transform, DiffTransform::BufferContent { .. })
7284        })
7285    }
7286
7287    fn is_at_end_of_excerpt(&self) -> bool {
7288        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
7289            return false;
7290        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
7291            || self.diff_transforms.item().is_none()
7292        {
7293            return true;
7294        }
7295
7296        let next_transform = self.diff_transforms.next_item();
7297        next_transform.is_none_or(|next_transform| match next_transform {
7298            DiffTransform::BufferContent { .. } => true,
7299            DiffTransform::DeletedHunk { hunk_info, .. } => self
7300                .excerpts
7301                .item()
7302                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
7303        })
7304    }
7305
7306    fn main_buffer_position(&self) -> Option<BD> {
7307        let excerpt = self.excerpts.item()?;
7308        let buffer = &excerpt.buffer;
7309        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7310        let mut buffer_start = buffer_context_start;
7311        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
7312        buffer_start += overshoot;
7313        Some(buffer_start)
7314    }
7315
7316    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
7317        let excerpt = self.excerpts.item()?;
7318        match self.diff_transforms.item()? {
7319            DiffTransform::DeletedHunk {
7320                buffer_id,
7321                base_text_byte_range,
7322                has_trailing_newline,
7323                hunk_info,
7324                ..
7325            } => {
7326                let diff = self.diffs.get(buffer_id)?;
7327                let buffer = diff.base_text();
7328                let mut rope_cursor = buffer.as_rope().cursor(0);
7329                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
7330                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
7331                let mut buffer_end = buffer_start;
7332                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
7333                let start = self.diff_transforms.start().output_dimension.0;
7334                let end = self.diff_transforms.end().output_dimension.0;
7335                Some(MultiBufferRegion {
7336                    buffer,
7337                    excerpt,
7338                    has_trailing_newline: *has_trailing_newline,
7339                    is_main_buffer: false,
7340                    diff_hunk_status: Some(DiffHunkStatus::deleted(
7341                        hunk_info.hunk_secondary_status,
7342                    )),
7343                    buffer_range: buffer_start..buffer_end,
7344                    range: start..end,
7345                })
7346            }
7347            DiffTransform::BufferContent {
7348                inserted_hunk_info, ..
7349            } => {
7350                let buffer = &excerpt.buffer;
7351                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
7352
7353                let mut start = self.diff_transforms.start().output_dimension.0;
7354                let mut buffer_start = buffer_context_start;
7355                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7356                    let overshoot =
7357                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7358                    start += overshoot;
7359                } else {
7360                    let overshoot =
7361                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
7362                    buffer_start += overshoot;
7363                }
7364
7365                let mut end;
7366                let mut buffer_end;
7367                let has_trailing_newline;
7368                let transform_end = self.diff_transforms.end();
7369                if transform_end.excerpt_dimension < self.excerpts.end() {
7370                    let overshoot = transform_end.excerpt_dimension - *self.excerpts.start();
7371                    end = transform_end.output_dimension.0;
7372                    buffer_end = buffer_context_start;
7373                    buffer_end += overshoot;
7374                    has_trailing_newline = false;
7375                } else {
7376                    let overshoot =
7377                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7378                    end = self.diff_transforms.start().output_dimension.0;
7379                    end += overshoot;
7380                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
7381                    has_trailing_newline = excerpt.has_trailing_newline;
7382                };
7383
7384                let diff_hunk_status = inserted_hunk_info.map(|info| {
7385                    if info.is_logically_deleted {
7386                        DiffHunkStatus::deleted(info.hunk_secondary_status)
7387                    } else {
7388                        DiffHunkStatus::added(info.hunk_secondary_status)
7389                    }
7390                });
7391
7392                Some(MultiBufferRegion {
7393                    buffer,
7394                    excerpt,
7395                    has_trailing_newline,
7396                    is_main_buffer: true,
7397                    diff_hunk_status,
7398                    buffer_range: buffer_start..buffer_end,
7399                    range: start..end,
7400                })
7401            }
7402        }
7403    }
7404
7405    fn fetch_excerpt_with_range(&self) -> Option<(&'a Excerpt, Range<MBD>)> {
7406        let excerpt = self.excerpts.item()?;
7407        match self.diff_transforms.item()? {
7408            &DiffTransform::DeletedHunk { .. } => {
7409                let start = self.diff_transforms.start().output_dimension.0;
7410                let end = self.diff_transforms.end().output_dimension.0;
7411                Some((excerpt, start..end))
7412            }
7413            DiffTransform::BufferContent { .. } => {
7414                let mut start = self.diff_transforms.start().output_dimension.0;
7415                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
7416                    let overshoot =
7417                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
7418                    start += overshoot;
7419                }
7420
7421                let mut end;
7422                let transform_end = self.diff_transforms.end();
7423                if transform_end.excerpt_dimension < self.excerpts.end() {
7424                    end = transform_end.output_dimension.0;
7425                } else {
7426                    let overshoot =
7427                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
7428                    end = self.diff_transforms.start().output_dimension.0;
7429                    end += overshoot;
7430                };
7431
7432                Some((excerpt, start..end))
7433            }
7434        }
7435    }
7436
7437    fn excerpt(&self) -> Option<&'a Excerpt> {
7438        self.excerpts.item()
7439    }
7440}
7441
7442impl Excerpt {
7443    fn new(
7444        id: ExcerptId,
7445        locator: Locator,
7446        buffer_id: BufferId,
7447        buffer: Arc<BufferSnapshot>,
7448        range: ExcerptRange<text::Anchor>,
7449        has_trailing_newline: bool,
7450    ) -> Self {
7451        Excerpt {
7452            id,
7453            locator,
7454            max_buffer_row: range.context.end.to_point(&buffer).row,
7455            text_summary: buffer
7456                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
7457            buffer_id,
7458            buffer,
7459            range,
7460            has_trailing_newline,
7461        }
7462    }
7463
7464    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
7465        let content_start = self.range.context.start.to_offset(&self.buffer);
7466        let chunks_start = content_start + range.start;
7467        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7468
7469        let has_footer = self.has_trailing_newline
7470            && range.start <= self.text_summary.len
7471            && range.end > self.text_summary.len;
7472
7473        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
7474
7475        ExcerptChunks {
7476            excerpt_id: self.id,
7477            content_chunks,
7478            has_footer,
7479        }
7480    }
7481
7482    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
7483        let content_start = self.range.context.start.to_offset(&self.buffer);
7484        let chunks_start = content_start + range.start;
7485        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
7486        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
7487        excerpt_chunks.has_footer = self.has_trailing_newline
7488            && range.start <= self.text_summary.len
7489            && range.end > self.text_summary.len;
7490    }
7491
7492    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
7493        if text_anchor
7494            .cmp(&self.range.context.start, &self.buffer)
7495            .is_lt()
7496        {
7497            self.range.context.start
7498        } else if text_anchor
7499            .cmp(&self.range.context.end, &self.buffer)
7500            .is_gt()
7501        {
7502            self.range.context.end
7503        } else {
7504            text_anchor
7505        }
7506    }
7507
7508    fn contains(&self, anchor: &Anchor) -> bool {
7509        (anchor.text_anchor.buffer_id == None
7510            || anchor.text_anchor.buffer_id == Some(self.buffer_id))
7511            && self
7512                .range
7513                .context
7514                .start
7515                .cmp(&anchor.text_anchor, &self.buffer)
7516                .is_le()
7517            && self
7518                .range
7519                .context
7520                .end
7521                .cmp(&anchor.text_anchor, &self.buffer)
7522                .is_ge()
7523    }
7524
7525    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7526    fn buffer_start_offset(&self) -> BufferOffset {
7527        BufferOffset(self.range.context.start.to_offset(&self.buffer))
7528    }
7529
7530    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7531    fn buffer_end_offset(&self) -> BufferOffset {
7532        self.buffer_start_offset() + self.text_summary.len
7533    }
7534}
7535
7536impl<'a> MultiBufferExcerpt<'a> {
7537    pub fn id(&self) -> ExcerptId {
7538        self.excerpt.id
7539    }
7540
7541    pub fn buffer_id(&self) -> BufferId {
7542        self.excerpt.buffer_id
7543    }
7544
7545    pub fn start_anchor(&self) -> Anchor {
7546        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.start)
7547    }
7548
7549    pub fn end_anchor(&self) -> Anchor {
7550        Anchor::in_buffer(self.excerpt.id, self.excerpt.range.context.end)
7551    }
7552
7553    pub fn buffer(&self) -> &'a BufferSnapshot {
7554        &self.excerpt.buffer
7555    }
7556
7557    pub fn buffer_range(&self) -> Range<BufferOffset> {
7558        self.buffer_offset
7559            ..BufferOffset(
7560                self.excerpt
7561                    .range
7562                    .context
7563                    .end
7564                    .to_offset(&self.excerpt.buffer.text),
7565            )
7566    }
7567
7568    pub fn start_offset(&self) -> MultiBufferOffset {
7569        self.offset
7570    }
7571
7572    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7573    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
7574        self.map_range_to_buffer(offset..offset).start
7575    }
7576
7577    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7578    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
7579        self.diff_transforms
7580            .seek(&OutputDimension(range.start), Bias::Right);
7581        let start = self.map_offset_to_buffer_internal(range.start);
7582        let end = if range.end > range.start {
7583            self.diff_transforms
7584                .seek_forward(&OutputDimension(range.end), Bias::Right);
7585            self.map_offset_to_buffer_internal(range.end)
7586        } else {
7587            start
7588        };
7589        start..end
7590    }
7591
7592    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
7593        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
7594        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7595            excerpt_offset += offset - self.diff_transforms.start().output_dimension.0;
7596        };
7597        let offset_in_excerpt = excerpt_offset.saturating_sub(self.excerpt_offset);
7598        self.buffer_offset + offset_in_excerpt
7599    }
7600
7601    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7602    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
7603        self.map_range_from_buffer(buffer_offset..buffer_offset)
7604            .start
7605    }
7606
7607    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7608    pub fn map_range_from_buffer(
7609        &mut self,
7610        buffer_range: Range<BufferOffset>,
7611    ) -> Range<MultiBufferOffset> {
7612        if buffer_range.start < self.buffer_offset {
7613            log::warn!(
7614                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7615            );
7616            return self.offset..self.offset;
7617        }
7618        let overshoot = buffer_range.start - self.buffer_offset;
7619        let excerpt_offset = self.excerpt_offset + overshoot;
7620        let excerpt_seek_dim = excerpt_offset;
7621        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
7622        if self.diff_transforms.start().excerpt_dimension > excerpt_offset {
7623            log::warn!(
7624                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7625            );
7626            return self.offset..self.offset;
7627        }
7628        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7629        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7630
7631        let end = if buffer_range.start < buffer_range.end {
7632            let overshoot = buffer_range.end - self.buffer_offset;
7633            let excerpt_offset = self.excerpt_offset + overshoot;
7634            let excerpt_seek_dim = excerpt_offset;
7635            self.diff_transforms
7636                .seek_forward(&excerpt_seek_dim, Bias::Right);
7637            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension;
7638            // todo(lw): Clamp end to the excerpt boundaries
7639            self.diff_transforms.start().output_dimension.0 + overshoot
7640        } else {
7641            start
7642        };
7643
7644        start..end
7645    }
7646
7647    /// Returns true if the entirety of the given range is in the buffer's excerpt
7648    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7649        range.start >= self.excerpt.buffer_start_offset()
7650            && range.end <= self.excerpt.buffer_end_offset()
7651    }
7652
7653    /// Returns true if any part of the given range is in the buffer's excerpt
7654    pub fn contains_partial_buffer_range(&self, range: Range<BufferOffset>) -> bool {
7655        range.start <= self.excerpt.buffer_end_offset()
7656            && range.end >= self.excerpt.buffer_start_offset()
7657    }
7658
7659    pub fn max_buffer_row(&self) -> u32 {
7660        self.excerpt.max_buffer_row
7661    }
7662}
7663
7664impl ExcerptId {
7665    pub fn min() -> Self {
7666        Self(0)
7667    }
7668
7669    pub fn max() -> Self {
7670        Self(u32::MAX)
7671    }
7672
7673    pub fn to_proto(self) -> u64 {
7674        self.0 as _
7675    }
7676
7677    pub fn from_proto(proto: u64) -> Self {
7678        Self(proto as _)
7679    }
7680
7681    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7682        let a = snapshot.excerpt_locator_for_id(*self);
7683        let b = snapshot.excerpt_locator_for_id(*other);
7684        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7685    }
7686}
7687
7688impl From<ExcerptId> for usize {
7689    fn from(val: ExcerptId) -> Self {
7690        val.0 as usize
7691    }
7692}
7693
7694impl fmt::Debug for Excerpt {
7695    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7696        f.debug_struct("Excerpt")
7697            .field("id", &self.id)
7698            .field("locator", &self.locator)
7699            .field("buffer_id", &self.buffer_id)
7700            .field("range", &self.range)
7701            .field("text_summary", &self.text_summary)
7702            .field("has_trailing_newline", &self.has_trailing_newline)
7703            .finish()
7704    }
7705}
7706
7707impl sum_tree::Item for Excerpt {
7708    type Summary = ExcerptSummary;
7709
7710    fn summary(&self, _cx: ()) -> Self::Summary {
7711        let mut text = self.text_summary;
7712        if self.has_trailing_newline {
7713            text += TextSummary::from("\n");
7714        }
7715        ExcerptSummary {
7716            excerpt_id: self.id,
7717            excerpt_locator: self.locator.clone(),
7718            widest_line_number: self.max_buffer_row,
7719            text: text.into(),
7720        }
7721    }
7722}
7723
7724impl sum_tree::Item for ExcerptIdMapping {
7725    type Summary = ExcerptId;
7726
7727    fn summary(&self, _cx: ()) -> Self::Summary {
7728        self.id
7729    }
7730}
7731
7732impl sum_tree::KeyedItem for ExcerptIdMapping {
7733    type Key = ExcerptId;
7734
7735    fn key(&self) -> Self::Key {
7736        self.id
7737    }
7738}
7739
7740impl DiffTransform {
7741    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7742        match self {
7743            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7744            DiffTransform::BufferContent {
7745                inserted_hunk_info, ..
7746            } => *inserted_hunk_info,
7747        }
7748    }
7749}
7750
7751impl sum_tree::Item for DiffTransform {
7752    type Summary = DiffTransformSummary;
7753
7754    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
7755        match self {
7756            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7757                input: *summary,
7758                output: *summary,
7759            },
7760            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7761                input: MBTextSummary::default(),
7762                output: summary.into(),
7763            },
7764        }
7765    }
7766}
7767
7768impl DiffTransformSummary {
7769    fn excerpt_len(&self) -> ExcerptOffset {
7770        ExcerptDimension(self.input.len)
7771    }
7772}
7773
7774impl sum_tree::ContextLessSummary for DiffTransformSummary {
7775    fn zero() -> Self {
7776        DiffTransformSummary {
7777            input: MBTextSummary::default(),
7778            output: MBTextSummary::default(),
7779        }
7780    }
7781
7782    fn add_summary(&mut self, other: &Self) {
7783        self.input += other.input;
7784        self.output += other.output;
7785    }
7786}
7787
7788impl sum_tree::ContextLessSummary for ExcerptId {
7789    fn zero() -> Self {
7790        Self(0)
7791    }
7792
7793    fn add_summary(&mut self, summary: &Self) {
7794        *self = cmp::max(*self, *summary);
7795    }
7796}
7797
7798impl sum_tree::ContextLessSummary for ExcerptSummary {
7799    fn zero() -> Self {
7800        Self::default()
7801    }
7802
7803    fn add_summary(&mut self, summary: &Self) {
7804        debug_assert!(
7805            summary.excerpt_locator > self.excerpt_locator
7806                || self.excerpt_locator == Locator::min(),
7807            "Excerpt locators must be in ascending order: {:?} > {:?}",
7808            summary.excerpt_locator,
7809            self.excerpt_locator
7810        );
7811        self.excerpt_locator = summary.excerpt_locator.clone();
7812        self.text += summary.text;
7813        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7814    }
7815}
7816
7817impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7818    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7819        Ord::cmp(&Some(self), cursor_location)
7820    }
7821}
7822
7823impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7824    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7825        Ord::cmp(self, &cursor_location.excerpt_locator)
7826    }
7827}
7828
7829impl<'a, MBD> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptDimension<MBD>
7830where
7831    MBD: MultiBufferDimension + Default,
7832{
7833    fn zero(_: ()) -> Self {
7834        ExcerptDimension(MBD::default())
7835    }
7836
7837    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7838        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7839    }
7840}
7841
7842impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7843    fn zero(_cx: ()) -> Self {
7844        Default::default()
7845    }
7846
7847    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7848        *self = Some(&summary.excerpt_locator);
7849    }
7850}
7851
7852impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7853    fn zero(_cx: ()) -> Self {
7854        Default::default()
7855    }
7856
7857    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7858        *self = Some(summary.excerpt_id);
7859    }
7860}
7861
7862#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7863struct OutputDimension<T>(T);
7864
7865impl<T: PartialEq> PartialEq<T> for OutputDimension<T> {
7866    fn eq(&self, other: &T) -> bool {
7867        self.0 == *other
7868    }
7869}
7870
7871impl<T: PartialOrd> PartialOrd<T> for OutputDimension<T> {
7872    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7873        self.0.partial_cmp(other)
7874    }
7875}
7876
7877impl<R, T, U> ops::Sub<OutputDimension<U>> for OutputDimension<T>
7878where
7879    T: ops::Sub<U, Output = R>,
7880{
7881    type Output = R;
7882
7883    fn sub(self, other: OutputDimension<U>) -> Self::Output {
7884        self.0 - other.0
7885    }
7886}
7887
7888impl<R, T, U> ops::Add<U> for OutputDimension<T>
7889where
7890    T: ops::Add<U, Output = R>,
7891{
7892    type Output = OutputDimension<R>;
7893
7894    fn add(self, other: U) -> Self::Output {
7895        OutputDimension(self.0 + other)
7896    }
7897}
7898
7899impl<T, U> AddAssign<U> for OutputDimension<T>
7900where
7901    T: AddAssign<U>,
7902{
7903    fn add_assign(&mut self, other: U) {
7904        self.0 += other;
7905    }
7906}
7907
7908impl<T, U> SubAssign<U> for OutputDimension<T>
7909where
7910    T: SubAssign<U>,
7911{
7912    fn sub_assign(&mut self, other: U) {
7913        self.0 -= other;
7914    }
7915}
7916
7917#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7918struct ExcerptDimension<T>(T);
7919
7920impl<T: PartialEq> PartialEq<T> for ExcerptDimension<T> {
7921    fn eq(&self, other: &T) -> bool {
7922        self.0 == *other
7923    }
7924}
7925
7926impl<T: PartialOrd> PartialOrd<T> for ExcerptDimension<T> {
7927    fn partial_cmp(&self, other: &T) -> Option<cmp::Ordering> {
7928        self.0.partial_cmp(other)
7929    }
7930}
7931
7932impl ExcerptOffset {
7933    fn saturating_sub(self, other: ExcerptOffset) -> usize {
7934        self.0.saturating_sub(other.0)
7935    }
7936}
7937
7938impl<R, T, U> ops::Sub<ExcerptDimension<U>> for ExcerptDimension<T>
7939where
7940    T: ops::Sub<U, Output = R>,
7941{
7942    type Output = R;
7943
7944    fn sub(self, other: ExcerptDimension<U>) -> Self::Output {
7945        self.0 - other.0
7946    }
7947}
7948
7949impl<R, T, U> ops::Add<U> for ExcerptDimension<T>
7950where
7951    T: ops::Add<U, Output = R>,
7952{
7953    type Output = ExcerptDimension<R>;
7954
7955    fn add(self, other: U) -> Self::Output {
7956        ExcerptDimension(self.0 + other)
7957    }
7958}
7959
7960impl<T, U> AddAssign<U> for ExcerptDimension<T>
7961where
7962    T: AddAssign<U>,
7963{
7964    fn add_assign(&mut self, other: U) {
7965        self.0 += other;
7966    }
7967}
7968
7969impl<T, U> SubAssign<U> for ExcerptDimension<T>
7970where
7971    T: SubAssign<U>,
7972{
7973    fn sub_assign(&mut self, other: U) {
7974        self.0 -= other;
7975    }
7976}
7977
7978impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7979    fn zero(_: ()) -> Self {
7980        MultiBufferOffset::ZERO
7981    }
7982
7983    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7984        *self += summary.output.len;
7985    }
7986}
7987
7988impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7989    for ExcerptDimension<MBD>
7990where
7991    MBD: MultiBufferDimension + Ord,
7992{
7993    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7994        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7995    }
7996}
7997
7998impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7999    for ExcerptDimension<MBD>
8000where
8001    MBD: MultiBufferDimension + Ord,
8002{
8003    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8004        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
8005    }
8006}
8007
8008impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8009    for ExcerptDimension<MBD>
8010{
8011    fn zero(_: ()) -> Self {
8012        ExcerptDimension(MBD::default())
8013    }
8014
8015    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8016        self.0.add_mb_text_summary(&summary.input)
8017    }
8018}
8019
8020impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
8021    for OutputDimension<MBD>
8022where
8023    MBD: MultiBufferDimension + Ord,
8024{
8025    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
8026        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
8027    }
8028}
8029
8030impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
8031    for OutputDimension<MBD>
8032{
8033    fn zero(_: ()) -> Self {
8034        OutputDimension(MBD::default())
8035    }
8036
8037    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
8038        self.0.add_mb_text_summary(&summary.output)
8039    }
8040}
8041
8042impl MultiBufferRows<'_> {
8043    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
8044        self.point = Point::new(row, 0);
8045        self.cursor.seek(&self.point);
8046    }
8047}
8048
8049impl Iterator for MultiBufferRows<'_> {
8050    type Item = RowInfo;
8051
8052    fn next(&mut self) -> Option<Self::Item> {
8053        if self.is_empty && self.point.row == 0 {
8054            self.point += Point::new(1, 0);
8055            return Some(RowInfo {
8056                buffer_id: None,
8057                buffer_row: Some(0),
8058                multibuffer_row: Some(MultiBufferRow(0)),
8059                diff_status: None,
8060                expand_info: None,
8061                wrapped_buffer_row: None,
8062            });
8063        }
8064
8065        let mut region = self.cursor.region()?.clone();
8066        while self.point >= region.range.end {
8067            self.cursor.next();
8068            if let Some(next_region) = self.cursor.region() {
8069                region = next_region.clone();
8070            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
8071                let multibuffer_row = MultiBufferRow(self.point.row);
8072                let last_excerpt = self
8073                    .cursor
8074                    .excerpts
8075                    .item()
8076                    .or(self.cursor.excerpts.prev_item())?;
8077                let last_row = last_excerpt
8078                    .range
8079                    .context
8080                    .end
8081                    .to_point(&last_excerpt.buffer)
8082                    .row;
8083
8084                let first_row = last_excerpt
8085                    .range
8086                    .context
8087                    .start
8088                    .to_point(&last_excerpt.buffer)
8089                    .row;
8090
8091                let expand_info = if self.is_singleton {
8092                    None
8093                } else {
8094                    let needs_expand_up = first_row == last_row
8095                        && last_row > 0
8096                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
8097                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
8098
8099                    if needs_expand_up && needs_expand_down {
8100                        Some(ExpandExcerptDirection::UpAndDown)
8101                    } else if needs_expand_up {
8102                        Some(ExpandExcerptDirection::Up)
8103                    } else if needs_expand_down {
8104                        Some(ExpandExcerptDirection::Down)
8105                    } else {
8106                        None
8107                    }
8108                    .map(|direction| ExpandInfo {
8109                        direction,
8110                        excerpt_id: last_excerpt.id,
8111                    })
8112                };
8113                self.point += Point::new(1, 0);
8114                return Some(RowInfo {
8115                    buffer_id: Some(last_excerpt.buffer_id),
8116                    buffer_row: Some(last_row),
8117                    multibuffer_row: Some(multibuffer_row),
8118                    diff_status: None,
8119                    wrapped_buffer_row: None,
8120                    expand_info,
8121                });
8122            } else {
8123                return None;
8124            };
8125        }
8126
8127        let overshoot = self.point - region.range.start;
8128        let buffer_point = region.buffer_range.start + overshoot;
8129        let expand_info = if self.is_singleton {
8130            None
8131        } else {
8132            let needs_expand_up = self.point.row == region.range.start.row
8133                && self.cursor.is_at_start_of_excerpt()
8134                && buffer_point.row > 0;
8135            let needs_expand_down = (region.excerpt.has_trailing_newline
8136                && self.point.row + 1 == region.range.end.row
8137                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
8138                && self.cursor.is_at_end_of_excerpt()
8139                && buffer_point.row < region.buffer.max_point().row;
8140
8141            if needs_expand_up && needs_expand_down {
8142                Some(ExpandExcerptDirection::UpAndDown)
8143            } else if needs_expand_up {
8144                Some(ExpandExcerptDirection::Up)
8145            } else if needs_expand_down {
8146                Some(ExpandExcerptDirection::Down)
8147            } else {
8148                None
8149            }
8150            .map(|direction| ExpandInfo {
8151                direction,
8152                excerpt_id: region.excerpt.id,
8153            })
8154        };
8155
8156        let result = Some(RowInfo {
8157            buffer_id: Some(region.buffer.remote_id()),
8158            buffer_row: Some(buffer_point.row),
8159            multibuffer_row: Some(MultiBufferRow(self.point.row)),
8160            diff_status: region
8161                .diff_hunk_status
8162                .filter(|_| self.point < region.range.end),
8163            expand_info,
8164            wrapped_buffer_row: None,
8165        });
8166        self.point += Point::new(1, 0);
8167        result
8168    }
8169}
8170
8171impl<'a> MultiBufferChunks<'a> {
8172    pub fn offset(&self) -> MultiBufferOffset {
8173        self.range.start
8174    }
8175
8176    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
8177        self.diff_transforms.seek(&range.end, Bias::Right);
8178        let mut excerpt_end = self.diff_transforms.start().1;
8179        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8180            let overshoot = range.end - self.diff_transforms.start().0;
8181            excerpt_end += overshoot;
8182        }
8183
8184        self.diff_transforms.seek(&range.start, Bias::Right);
8185        let mut excerpt_start = self.diff_transforms.start().1;
8186        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
8187            let overshoot = range.start - self.diff_transforms.start().0;
8188            excerpt_start += overshoot;
8189        }
8190
8191        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
8192        self.buffer_chunk.take();
8193        self.range = range;
8194    }
8195
8196    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
8197        self.excerpt_offset_range = new_range.clone();
8198        self.excerpts.seek(&new_range.start, Bias::Right);
8199        if let Some(excerpt) = self.excerpts.item() {
8200            let excerpt_start = *self.excerpts.start();
8201            if let Some(excerpt_chunks) = self
8202                .excerpt_chunks
8203                .as_mut()
8204                .filter(|chunks| excerpt.id == chunks.excerpt_id)
8205            {
8206                excerpt.seek_chunks(
8207                    excerpt_chunks,
8208                    (self.excerpt_offset_range.start - excerpt_start)
8209                        ..(self.excerpt_offset_range.end - excerpt_start),
8210                );
8211            } else {
8212                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8213                    (self.excerpt_offset_range.start - excerpt_start)
8214                        ..(self.excerpt_offset_range.end - excerpt_start),
8215                    self.language_aware,
8216                ));
8217            }
8218        } else {
8219            self.excerpt_chunks = None;
8220        }
8221    }
8222
8223    #[ztracing::instrument(skip_all)]
8224    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
8225        loop {
8226            if self.excerpt_offset_range.is_empty() {
8227                return None;
8228            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
8229                self.excerpt_offset_range.start += chunk.text.len();
8230                return Some(chunk);
8231            } else {
8232                self.excerpts.next();
8233                let excerpt = self.excerpts.item()?;
8234                self.excerpt_chunks = Some(excerpt.chunks_in_range(
8235                    0..(self.excerpt_offset_range.end - *self.excerpts.start()),
8236                    self.language_aware,
8237                ));
8238            }
8239        }
8240    }
8241}
8242
8243impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
8244    type Item = &'a str;
8245
8246    fn next(&mut self) -> Option<Self::Item> {
8247        let mut region = self.cursor.region()?;
8248        if self.offset == region.range.start {
8249            self.cursor.prev();
8250            region = self.cursor.region()?;
8251            let start_overshoot = self.start.saturating_sub(region.range.start);
8252            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
8253                region.buffer_range.start + start_overshoot..region.buffer_range.end,
8254            ));
8255        }
8256
8257        if self.offset == region.range.end && region.has_trailing_newline {
8258            self.offset -= 1;
8259            Some("\n")
8260        } else {
8261            let chunk = self.current_chunks.as_mut().unwrap().next()?;
8262            self.offset -= chunk.len();
8263            Some(chunk)
8264        }
8265    }
8266}
8267
8268impl<'a> Iterator for MultiBufferChunks<'a> {
8269    type Item = Chunk<'a>;
8270
8271    #[ztracing::instrument(skip_all)]
8272    fn next(&mut self) -> Option<Chunk<'a>> {
8273        if self.range.start >= self.range.end {
8274            return None;
8275        }
8276        if self.range.start == self.diff_transforms.end().0 {
8277            self.diff_transforms.next();
8278        }
8279
8280        let diff_transform_start = self.diff_transforms.start().0;
8281        let diff_transform_end = self.diff_transforms.end().0;
8282        debug_assert!(
8283            self.range.start < diff_transform_end,
8284            "{:?} < {:?} of ({1:?}..{2:?})",
8285            self.range.start,
8286            diff_transform_end,
8287            diff_transform_start
8288        );
8289
8290        let diff_transform = self.diff_transforms.item()?;
8291        match diff_transform {
8292            DiffTransform::BufferContent { .. } => {
8293                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
8294                    chunk
8295                } else {
8296                    let chunk = self.next_excerpt_chunk().unwrap();
8297                    self.buffer_chunk.insert(chunk)
8298                };
8299
8300                let chunk_end = self.range.start + chunk.text.len();
8301                let diff_transform_end = diff_transform_end.min(self.range.end);
8302
8303                if diff_transform_end < chunk_end {
8304                    let split_idx = diff_transform_end - self.range.start;
8305                    let (before, after) = chunk.text.split_at(split_idx);
8306                    self.range.start = diff_transform_end;
8307                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
8308                    let chars = chunk.chars & mask;
8309                    let tabs = chunk.tabs & mask;
8310
8311                    chunk.text = after;
8312                    chunk.chars = chunk.chars >> split_idx;
8313                    chunk.tabs = chunk.tabs >> split_idx;
8314
8315                    Some(Chunk {
8316                        text: before,
8317                        chars,
8318                        tabs,
8319                        ..chunk.clone()
8320                    })
8321                } else {
8322                    self.range.start = chunk_end;
8323                    self.buffer_chunk.take()
8324                }
8325            }
8326            DiffTransform::DeletedHunk {
8327                buffer_id,
8328                base_text_byte_range,
8329                has_trailing_newline,
8330                ..
8331            } => {
8332                let base_text_start =
8333                    base_text_byte_range.start + (self.range.start - diff_transform_start);
8334                let base_text_end =
8335                    base_text_byte_range.start + (self.range.end - diff_transform_start);
8336                let base_text_end = base_text_end.min(base_text_byte_range.end);
8337
8338                let mut chunks = if let Some((_, mut chunks)) = self
8339                    .diff_base_chunks
8340                    .take()
8341                    .filter(|(id, _)| id == buffer_id)
8342                {
8343                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
8344                    {
8345                        chunks.seek(base_text_start..base_text_end);
8346                    }
8347                    chunks
8348                } else {
8349                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
8350                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
8351                };
8352
8353                let chunk = if let Some(chunk) = chunks.next() {
8354                    self.range.start += chunk.text.len();
8355                    self.diff_base_chunks = Some((*buffer_id, chunks));
8356                    chunk
8357                } else {
8358                    debug_assert!(has_trailing_newline);
8359                    self.range.start += "\n".len();
8360                    Chunk {
8361                        text: "\n",
8362                        chars: 1u128,
8363                        ..Default::default()
8364                    }
8365                };
8366                Some(chunk)
8367            }
8368        }
8369    }
8370}
8371
8372impl MultiBufferBytes<'_> {
8373    fn consume(&mut self, len: usize) {
8374        self.range.start += len;
8375        self.chunk = &self.chunk[len..];
8376
8377        if !self.range.is_empty() && self.chunk.is_empty() {
8378            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
8379                self.chunk = chunk;
8380            } else if self.has_trailing_newline {
8381                self.has_trailing_newline = false;
8382                self.chunk = b"\n";
8383            } else {
8384                self.cursor.next();
8385                if let Some(region) = self.cursor.region() {
8386                    let mut excerpt_bytes = region.buffer.bytes_in_range(
8387                        region.buffer_range.start
8388                            ..(region.buffer_range.start + (self.range.end - region.range.start))
8389                                .min(region.buffer_range.end),
8390                    );
8391                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
8392                    self.excerpt_bytes = Some(excerpt_bytes);
8393                    self.has_trailing_newline =
8394                        region.has_trailing_newline && self.range.end >= region.range.end;
8395                    if self.chunk.is_empty() && self.has_trailing_newline {
8396                        self.has_trailing_newline = false;
8397                        self.chunk = b"\n";
8398                    }
8399                }
8400            }
8401        }
8402    }
8403}
8404
8405impl<'a> Iterator for MultiBufferBytes<'a> {
8406    type Item = &'a [u8];
8407
8408    fn next(&mut self) -> Option<Self::Item> {
8409        let chunk = self.chunk;
8410        if chunk.is_empty() {
8411            None
8412        } else {
8413            self.consume(chunk.len());
8414            Some(chunk)
8415        }
8416    }
8417}
8418
8419impl io::Read for MultiBufferBytes<'_> {
8420    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8421        let len = cmp::min(buf.len(), self.chunk.len());
8422        buf[..len].copy_from_slice(&self.chunk[..len]);
8423        if len > 0 {
8424            self.consume(len);
8425        }
8426        Ok(len)
8427    }
8428}
8429
8430impl io::Read for ReversedMultiBufferBytes<'_> {
8431    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
8432        let len = cmp::min(buf.len(), self.chunk.len());
8433        buf[..len].copy_from_slice(&self.chunk[..len]);
8434        buf[..len].reverse();
8435        if len > 0 {
8436            self.range.end -= len;
8437            self.chunk = &self.chunk[..self.chunk.len() - len];
8438            if !self.range.is_empty()
8439                && self.chunk.is_empty()
8440                && let Some(chunk) = self.chunks.next()
8441            {
8442                self.chunk = chunk.as_bytes();
8443            }
8444        }
8445        Ok(len)
8446    }
8447}
8448
8449impl<'a> Iterator for ExcerptChunks<'a> {
8450    type Item = Chunk<'a>;
8451
8452    fn next(&mut self) -> Option<Self::Item> {
8453        if let Some(chunk) = self.content_chunks.next() {
8454            return Some(chunk);
8455        }
8456
8457        if self.has_footer {
8458            let text = "\n";
8459            let chars = 0b1;
8460            self.has_footer = false;
8461            return Some(Chunk {
8462                text,
8463                chars,
8464                ..Default::default()
8465            });
8466        }
8467
8468        None
8469    }
8470}
8471
8472impl ToOffset for Point {
8473    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8474        snapshot.point_to_offset(*self)
8475    }
8476    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8477        snapshot.point_to_offset_utf16(*self)
8478    }
8479}
8480
8481impl ToOffset for MultiBufferOffset {
8482    #[track_caller]
8483    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8484        assert!(
8485            *self <= snapshot.len(),
8486            "offset {} is greater than the snapshot.len() {}",
8487            self.0,
8488            snapshot.len().0,
8489        );
8490        *self
8491    }
8492    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8493        snapshot.offset_to_offset_utf16(*self)
8494    }
8495}
8496
8497impl ToOffset for MultiBufferOffsetUtf16 {
8498    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8499        snapshot.offset_utf16_to_offset(*self)
8500    }
8501
8502    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8503        *self
8504    }
8505}
8506
8507impl ToOffset for PointUtf16 {
8508    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
8509        snapshot.point_utf16_to_offset(*self)
8510    }
8511    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
8512        snapshot.point_utf16_to_offset_utf16(*self)
8513    }
8514}
8515
8516impl ToPoint for MultiBufferOffset {
8517    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8518        snapshot.offset_to_point(*self)
8519    }
8520    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8521        snapshot.offset_to_point_utf16(*self)
8522    }
8523}
8524
8525impl ToPoint for Point {
8526    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
8527        *self
8528    }
8529    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
8530        snapshot.point_to_point_utf16(*self)
8531    }
8532}
8533
8534impl ToPoint for PointUtf16 {
8535    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
8536        snapshot.point_utf16_to_point(*self)
8537    }
8538    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
8539        *self
8540    }
8541}
8542
8543impl From<ExcerptId> for EntityId {
8544    fn from(id: ExcerptId) -> Self {
8545        EntityId::from(id.0 as u64)
8546    }
8547}
8548
8549#[cfg(debug_assertions)]
8550pub mod debug {
8551    use super::*;
8552
8553    pub trait ToMultiBufferDebugRanges {
8554        fn to_multi_buffer_debug_ranges(
8555            &self,
8556            snapshot: &MultiBufferSnapshot,
8557        ) -> Vec<Range<MultiBufferOffset>>;
8558    }
8559
8560    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
8561        fn to_multi_buffer_debug_ranges(
8562            &self,
8563            snapshot: &MultiBufferSnapshot,
8564        ) -> Vec<Range<MultiBufferOffset>> {
8565            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
8566        }
8567    }
8568
8569    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
8570        fn to_multi_buffer_debug_ranges(
8571            &self,
8572            snapshot: &MultiBufferSnapshot,
8573        ) -> Vec<Range<MultiBufferOffset>> {
8574            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
8575                .to_multi_buffer_debug_ranges(snapshot)
8576        }
8577    }
8578
8579    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
8580        fn to_multi_buffer_debug_ranges(
8581            &self,
8582            snapshot: &MultiBufferSnapshot,
8583        ) -> Vec<Range<MultiBufferOffset>> {
8584            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8585        }
8586    }
8587
8588    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
8589        fn to_multi_buffer_debug_ranges(
8590            &self,
8591            snapshot: &MultiBufferSnapshot,
8592        ) -> Vec<Range<MultiBufferOffset>> {
8593            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
8594        }
8595    }
8596
8597    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
8598        fn to_multi_buffer_debug_ranges(
8599            &self,
8600            snapshot: &MultiBufferSnapshot,
8601        ) -> Vec<Range<MultiBufferOffset>> {
8602            self.iter()
8603                .map(|item| {
8604                    let offset = item.to_offset(snapshot);
8605                    offset..offset
8606                })
8607                .collect()
8608        }
8609    }
8610
8611    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
8612        fn to_multi_buffer_debug_ranges(
8613            &self,
8614            snapshot: &MultiBufferSnapshot,
8615        ) -> Vec<Range<MultiBufferOffset>> {
8616            self.iter()
8617                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
8618                .collect()
8619        }
8620    }
8621}