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