multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod path_key;
   5mod position;
   6mod transaction;
   7
   8use self::transaction::History;
   9
  10pub use anchor::{Anchor, AnchorRangeExt};
  11pub use position::{TypedOffset, TypedPoint, TypedRow};
  12
  13use anyhow::{Result, anyhow};
  14use buffer_diff::{
  15    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  16    DiffHunkStatusKind,
  17};
  18use clock::ReplicaId;
  19use collections::{BTreeMap, Bound, HashMap, HashSet};
  20use gpui::{App, Context, Entity, EntityId, EventEmitter};
  21use itertools::Itertools;
  22use language::{
  23    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  24    CharKind, CharScopeContext, Chunk, CursorShape, DiagnosticEntryRef, DiskState, File,
  25    IndentGuideSettings, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16, Outline,
  26    OutlineItem, Point, PointUtf16, Selection, TextDimension, TextObject, ToOffset as _,
  27    ToPoint as _, TransactionId, TreeSitterOptions, Unclipped,
  28    language_settings::{LanguageSettings, language_settings},
  29};
  30
  31#[cfg(any(test, feature = "test-support"))]
  32use gpui::AppContext as _;
  33
  34use rope::DimensionPair;
  35use smallvec::SmallVec;
  36use smol::future::yield_now;
  37use std::{
  38    any::type_name,
  39    borrow::Cow,
  40    cell::{Cell, Ref, RefCell},
  41    cmp, fmt,
  42    future::Future,
  43    io,
  44    iter::{self, FromIterator},
  45    mem,
  46    ops::{self, AddAssign, Range, RangeBounds, Sub},
  47    rc::Rc,
  48    str,
  49    sync::Arc,
  50    time::Duration,
  51};
  52use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, TreeMap};
  53use text::{
  54    BufferId, Edit, LineIndent, TextSummary,
  55    locator::Locator,
  56    subscription::{Subscription, Topic},
  57};
  58use theme::SyntaxTheme;
  59use util::post_inc;
  60
  61pub use self::path_key::PathKey;
  62
  63#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  64pub struct ExcerptId(u32);
  65
  66/// One or more [`Buffers`](Buffer) being edited in a single view.
  67///
  68/// See <https://zed.dev/features#multi-buffers>
  69pub struct MultiBuffer {
  70    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  71    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  72    snapshot: RefCell<MultiBufferSnapshot>,
  73    /// Contains the state of the buffers being edited
  74    buffers: HashMap<BufferId, BufferState>,
  75    /// Mapping from path keys to their excerpts.
  76    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  77    /// Mapping from excerpt IDs to their path key.
  78    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  79    /// Mapping from buffer IDs to their diff states
  80    diffs: HashMap<BufferId, DiffState>,
  81    subscriptions: Topic<MultiBufferOffset>,
  82    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  83    singleton: bool,
  84    /// The history of the multi-buffer.
  85    history: History,
  86    /// The explicit title of the multi-buffer.
  87    /// If `None`, it will be derived from the underlying path or content.
  88    title: Option<String>,
  89    /// The writing capability of the multi-buffer.
  90    capability: Capability,
  91    buffer_changed_since_sync: Rc<Cell<bool>>,
  92}
  93
  94#[derive(Clone, Debug, PartialEq, Eq)]
  95pub enum Event {
  96    ExcerptsAdded {
  97        buffer: Entity<Buffer>,
  98        predecessor: ExcerptId,
  99        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
 100    },
 101    ExcerptsRemoved {
 102        ids: Vec<ExcerptId>,
 103        removed_buffer_ids: Vec<BufferId>,
 104    },
 105    ExcerptsExpanded {
 106        ids: Vec<ExcerptId>,
 107    },
 108    ExcerptsEdited {
 109        excerpt_ids: Vec<ExcerptId>,
 110        buffer_ids: Vec<BufferId>,
 111    },
 112    DiffHunksToggled,
 113    Edited {
 114        edited_buffer: Option<Entity<Buffer>>,
 115    },
 116    TransactionUndone {
 117        transaction_id: TransactionId,
 118    },
 119    Reloaded,
 120    LanguageChanged(BufferId),
 121    Reparsed(BufferId),
 122    Saved,
 123    FileHandleChanged,
 124    DirtyChanged,
 125    DiagnosticsUpdated,
 126    BufferDiffChanged,
 127}
 128
 129/// A diff hunk, representing a range of consequent lines in a multibuffer.
 130#[derive(Debug, Clone, PartialEq, Eq)]
 131pub struct MultiBufferDiffHunk {
 132    /// The row range in the multibuffer where this diff hunk appears.
 133    pub row_range: Range<MultiBufferRow>,
 134    /// The buffer ID that this hunk belongs to.
 135    pub buffer_id: BufferId,
 136    /// The range of the underlying buffer that this hunk corresponds to.
 137    pub buffer_range: Range<text::Anchor>,
 138    /// The excerpt that contains the diff hunk.
 139    pub excerpt_id: ExcerptId,
 140    /// The range within the buffer's diff base that this hunk corresponds to.
 141    pub diff_base_byte_range: Range<BufferOffset>,
 142    /// Whether or not this hunk also appears in the 'secondary diff'.
 143    pub secondary_status: DiffHunkSecondaryStatus,
 144}
 145
 146impl MultiBufferDiffHunk {
 147    pub fn status(&self) -> DiffHunkStatus {
 148        let kind = if self.buffer_range.start == self.buffer_range.end {
 149            DiffHunkStatusKind::Deleted
 150        } else if self.diff_base_byte_range.is_empty() {
 151            DiffHunkStatusKind::Added
 152        } else {
 153            DiffHunkStatusKind::Modified
 154        };
 155        DiffHunkStatus {
 156            kind,
 157            secondary: self.secondary_status,
 158        }
 159    }
 160
 161    pub fn is_created_file(&self) -> bool {
 162        self.diff_base_byte_range == (BufferOffset(0)..BufferOffset(0))
 163            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 164    }
 165
 166    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 167        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 168        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 169        start..end
 170    }
 171}
 172
 173pub type MultiBufferPoint = Point;
 174type ExcerptOffset = TypedOffset<Excerpt>;
 175type ExcerptPoint = TypedPoint<Excerpt>;
 176
 177#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 178#[serde(transparent)]
 179pub struct MultiBufferRow(pub u32);
 180
 181impl MultiBufferRow {
 182    pub const MIN: Self = Self(0);
 183    pub const MAX: Self = Self(u32::MAX);
 184}
 185
 186impl ops::Add<usize> for MultiBufferRow {
 187    type Output = Self;
 188
 189    fn add(self, rhs: usize) -> Self::Output {
 190        MultiBufferRow(self.0 + rhs as u32)
 191    }
 192}
 193
 194pub trait MultiBufferDimension: 'static + Copy + Default + std::fmt::Debug {
 195    type TextDimension: TextDimension;
 196    fn from_summary(summary: &MBTextSummary) -> Self;
 197
 198    fn add_text_dim(&mut self, summary: &Self::TextDimension);
 199
 200    fn add_mb_text_summary(&mut self, summary: &MBTextSummary);
 201}
 202
 203// todo(lw): MultiBufferPoint
 204impl MultiBufferDimension for Point {
 205    type TextDimension = Point;
 206    fn from_summary(summary: &MBTextSummary) -> Self {
 207        summary.lines
 208    }
 209
 210    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 211        *self += *other;
 212    }
 213
 214    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 215        *self += summary.lines;
 216    }
 217}
 218
 219// todo(lw): MultiBufferPointUtf16
 220impl MultiBufferDimension for PointUtf16 {
 221    type TextDimension = PointUtf16;
 222    fn from_summary(summary: &MBTextSummary) -> Self {
 223        summary.lines_utf16()
 224    }
 225
 226    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 227        *self += *other;
 228    }
 229
 230    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 231        *self += summary.lines_utf16();
 232    }
 233}
 234
 235#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 236pub struct MultiBufferOffset(pub usize);
 237
 238impl fmt::Display for MultiBufferOffset {
 239    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 240        write!(f, "{}", self.0)
 241    }
 242}
 243
 244impl rand::distr::uniform::SampleUniform for MultiBufferOffset {
 245    type Sampler = MultiBufferOffsetUniformSampler;
 246}
 247
 248pub struct MultiBufferOffsetUniformSampler {
 249    sampler: rand::distr::uniform::UniformUsize,
 250}
 251
 252impl rand::distr::uniform::UniformSampler for MultiBufferOffsetUniformSampler {
 253    type X = MultiBufferOffset;
 254
 255    fn new<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 256    where
 257        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 258        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 259    {
 260        let low = *low_b.borrow();
 261        let high = *high_b.borrow();
 262        let sampler = rand::distr::uniform::UniformUsize::new(low.0, high.0);
 263        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 264    }
 265
 266    #[inline] // if the range is constant, this helps LLVM to do the
 267    // calculations at compile-time.
 268    fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Result<Self, rand::distr::uniform::Error>
 269    where
 270        B1: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 271        B2: rand::distr::uniform::SampleBorrow<Self::X> + Sized,
 272    {
 273        let low = *low_b.borrow();
 274        let high = *high_b.borrow();
 275        let sampler = rand::distr::uniform::UniformUsize::new_inclusive(low.0, high.0);
 276        sampler.map(|sampler| MultiBufferOffsetUniformSampler { sampler })
 277    }
 278
 279    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Self::X {
 280        MultiBufferOffset(self.sampler.sample(rng))
 281    }
 282}
 283impl MultiBufferDimension for MultiBufferOffset {
 284    type TextDimension = usize;
 285    fn from_summary(summary: &MBTextSummary) -> Self {
 286        summary.len
 287    }
 288
 289    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 290        self.0 += *other;
 291    }
 292
 293    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 294        *self += summary.len;
 295    }
 296}
 297impl MultiBufferDimension for MultiBufferOffsetUtf16 {
 298    type TextDimension = OffsetUtf16;
 299    fn from_summary(summary: &MBTextSummary) -> Self {
 300        MultiBufferOffsetUtf16(summary.len_utf16)
 301    }
 302
 303    fn add_text_dim(&mut self, other: &Self::TextDimension) {
 304        self.0 += *other;
 305    }
 306
 307    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 308        self.0 += summary.len_utf16;
 309    }
 310}
 311
 312#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 313pub struct BufferOffset(pub usize);
 314
 315impl TextDimension for BufferOffset {
 316    fn from_text_summary(summary: &TextSummary) -> Self {
 317        BufferOffset(usize::from_text_summary(summary))
 318    }
 319    fn from_chunk(chunk: rope::ChunkSlice) -> Self {
 320        BufferOffset(usize::from_chunk(chunk))
 321    }
 322    fn add_assign(&mut self, other: &Self) {
 323        TextDimension::add_assign(&mut self.0, &other.0);
 324    }
 325}
 326impl<'a> sum_tree::Dimension<'a, rope::ChunkSummary> for BufferOffset {
 327    fn zero(cx: ()) -> Self {
 328        BufferOffset(<usize as sum_tree::Dimension<'a, rope::ChunkSummary>>::zero(cx))
 329    }
 330
 331    fn add_summary(&mut self, summary: &'a rope::ChunkSummary, cx: ()) {
 332        usize::add_summary(&mut self.0, summary, cx);
 333    }
 334}
 335
 336impl Sub for BufferOffset {
 337    type Output = usize;
 338
 339    fn sub(self, other: BufferOffset) -> Self::Output {
 340        self.0 - other.0
 341    }
 342}
 343
 344impl AddAssign<DimensionPair<usize, Point>> for BufferOffset {
 345    fn add_assign(&mut self, other: DimensionPair<usize, Point>) {
 346        self.0 += other.key;
 347    }
 348}
 349
 350impl language::ToPoint for BufferOffset {
 351    fn to_point(&self, snapshot: &text::BufferSnapshot) -> Point {
 352        self.0.to_point(snapshot)
 353    }
 354}
 355
 356impl language::ToPointUtf16 for BufferOffset {
 357    fn to_point_utf16(&self, snapshot: &text::BufferSnapshot) -> PointUtf16 {
 358        self.0.to_point_utf16(snapshot)
 359    }
 360}
 361
 362impl language::ToOffset for BufferOffset {
 363    fn to_offset(&self, snapshot: &text::BufferSnapshot) -> usize {
 364        self.0.to_offset(snapshot)
 365    }
 366}
 367
 368impl language::ToOffsetUtf16 for BufferOffset {
 369    fn to_offset_utf16(&self, snapshot: &text::BufferSnapshot) -> OffsetUtf16 {
 370        self.0.to_offset_utf16(snapshot)
 371    }
 372}
 373
 374#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 375pub struct MultiBufferOffsetUtf16(pub OffsetUtf16);
 376
 377impl ops::Add<usize> for MultiBufferOffsetUtf16 {
 378    type Output = MultiBufferOffsetUtf16;
 379
 380    fn add(self, rhs: usize) -> Self::Output {
 381        MultiBufferOffsetUtf16(OffsetUtf16(self.0.0 + rhs))
 382    }
 383}
 384
 385impl AddAssign<OffsetUtf16> for MultiBufferOffsetUtf16 {
 386    fn add_assign(&mut self, rhs: OffsetUtf16) {
 387        self.0 += rhs;
 388    }
 389}
 390
 391impl AddAssign<usize> for MultiBufferOffsetUtf16 {
 392    fn add_assign(&mut self, rhs: usize) {
 393        self.0.0 += rhs;
 394    }
 395}
 396
 397impl Sub for MultiBufferOffsetUtf16 {
 398    type Output = OffsetUtf16;
 399
 400    fn sub(self, other: MultiBufferOffsetUtf16) -> Self::Output {
 401        self.0 - other.0
 402    }
 403}
 404
 405#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 406pub struct BufferOffsetUtf16(pub OffsetUtf16);
 407
 408impl MultiBufferOffset {
 409    const ZERO: Self = Self(0);
 410    pub fn saturating_sub(self, other: MultiBufferOffset) -> usize {
 411        self.0.saturating_sub(other.0)
 412    }
 413    pub fn saturating_sub_usize(self, other: usize) -> MultiBufferOffset {
 414        MultiBufferOffset(self.0.saturating_sub(other))
 415    }
 416}
 417
 418impl ops::Sub for MultiBufferOffset {
 419    type Output = usize;
 420
 421    fn sub(self, other: MultiBufferOffset) -> Self::Output {
 422        self.0 - other.0
 423    }
 424}
 425
 426impl ops::Sub<usize> for MultiBufferOffset {
 427    type Output = Self;
 428
 429    fn sub(self, other: usize) -> Self::Output {
 430        MultiBufferOffset(self.0 - other)
 431    }
 432}
 433
 434impl ops::SubAssign<usize> for MultiBufferOffset {
 435    fn sub_assign(&mut self, other: usize) {
 436        self.0 -= other;
 437    }
 438}
 439
 440impl ops::Add<usize> for BufferOffset {
 441    type Output = Self;
 442
 443    fn add(self, rhs: usize) -> Self::Output {
 444        BufferOffset(self.0 + rhs)
 445    }
 446}
 447
 448impl ops::AddAssign<usize> for BufferOffset {
 449    fn add_assign(&mut self, other: usize) {
 450        self.0 += other;
 451    }
 452}
 453
 454impl ops::Add<usize> for MultiBufferOffset {
 455    type Output = Self;
 456
 457    fn add(self, rhs: usize) -> Self::Output {
 458        MultiBufferOffset(self.0 + rhs)
 459    }
 460}
 461
 462impl ops::AddAssign<usize> for MultiBufferOffset {
 463    fn add_assign(&mut self, other: usize) {
 464        self.0 += other;
 465    }
 466}
 467
 468impl ops::Add<isize> for MultiBufferOffset {
 469    type Output = Self;
 470
 471    fn add(self, rhs: isize) -> Self::Output {
 472        MultiBufferOffset((self.0 as isize + rhs) as usize)
 473    }
 474}
 475
 476impl ops::Add for MultiBufferOffset {
 477    type Output = Self;
 478
 479    fn add(self, rhs: MultiBufferOffset) -> Self::Output {
 480        MultiBufferOffset(self.0 + rhs.0)
 481    }
 482}
 483
 484impl ops::AddAssign<MultiBufferOffset> for MultiBufferOffset {
 485    fn add_assign(&mut self, other: MultiBufferOffset) {
 486        self.0 += other.0;
 487    }
 488}
 489
 490pub trait ToOffset: 'static + fmt::Debug {
 491    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset;
 492    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16;
 493}
 494
 495pub trait ToPoint: 'static + fmt::Debug {
 496    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 497    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 498}
 499
 500struct BufferState {
 501    buffer: Entity<Buffer>,
 502    last_version: RefCell<clock::Global>,
 503    last_non_text_state_update_count: Cell<usize>,
 504    excerpts: Vec<Locator>,
 505    _subscriptions: [gpui::Subscription; 2],
 506}
 507
 508struct DiffState {
 509    diff: Entity<BufferDiff>,
 510    _subscription: gpui::Subscription,
 511}
 512
 513impl DiffState {
 514    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 515        DiffState {
 516            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 517                BufferDiffEvent::DiffChanged { changed_range } => {
 518                    if let Some(changed_range) = changed_range.clone() {
 519                        this.buffer_diff_changed(diff, changed_range, cx)
 520                    }
 521                    cx.emit(Event::BufferDiffChanged);
 522                }
 523                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 524                _ => {}
 525            }),
 526            diff,
 527        }
 528    }
 529}
 530
 531/// The contents of a [`MultiBuffer`] at a single point in time.
 532#[derive(Clone, Default)]
 533pub struct MultiBufferSnapshot {
 534    excerpts: SumTree<Excerpt>,
 535    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 536    diff_transforms: SumTree<DiffTransform>,
 537    non_text_state_update_count: usize,
 538    edit_count: usize,
 539    is_dirty: bool,
 540    has_deleted_file: bool,
 541    has_conflict: bool,
 542    /// immutable fields
 543    singleton: bool,
 544    excerpt_ids: SumTree<ExcerptIdMapping>,
 545    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 546    trailing_excerpt_update_count: usize,
 547    all_diff_hunks_expanded: bool,
 548    show_headers: bool,
 549}
 550
 551#[derive(Debug, Clone)]
 552enum DiffTransform {
 553    BufferContent {
 554        summary: MBTextSummary,
 555        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 556    },
 557    DeletedHunk {
 558        summary: TextSummary,
 559        buffer_id: BufferId,
 560        hunk_info: DiffTransformHunkInfo,
 561        base_text_byte_range: Range<usize>,
 562        has_trailing_newline: bool,
 563    },
 564}
 565
 566#[derive(Clone, Copy, Debug)]
 567struct DiffTransformHunkInfo {
 568    excerpt_id: ExcerptId,
 569    hunk_start_anchor: text::Anchor,
 570    hunk_secondary_status: DiffHunkSecondaryStatus,
 571}
 572
 573impl Eq for DiffTransformHunkInfo {}
 574
 575impl PartialEq for DiffTransformHunkInfo {
 576    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 577        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 578    }
 579}
 580
 581impl std::hash::Hash for DiffTransformHunkInfo {
 582    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 583        self.excerpt_id.hash(state);
 584        self.hunk_start_anchor.hash(state);
 585    }
 586}
 587
 588#[derive(Clone)]
 589pub struct ExcerptInfo {
 590    pub id: ExcerptId,
 591    pub buffer: BufferSnapshot,
 592    pub buffer_id: BufferId,
 593    pub range: ExcerptRange<text::Anchor>,
 594    pub end_row: MultiBufferRow,
 595}
 596
 597impl std::fmt::Debug for ExcerptInfo {
 598    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 599        f.debug_struct(type_name::<Self>())
 600            .field("id", &self.id)
 601            .field("buffer_id", &self.buffer_id)
 602            .field("path", &self.buffer.file().map(|f| f.path()))
 603            .field("range", &self.range)
 604            .finish()
 605    }
 606}
 607
 608/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 609#[derive(Debug)]
 610pub struct ExcerptBoundary {
 611    pub prev: Option<ExcerptInfo>,
 612    pub next: ExcerptInfo,
 613    /// The row in the `MultiBuffer` where the boundary is located
 614    pub row: MultiBufferRow,
 615}
 616
 617impl ExcerptBoundary {
 618    pub fn starts_new_buffer(&self) -> bool {
 619        match (self.prev.as_ref(), &self.next) {
 620            (None, _) => true,
 621            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 622        }
 623    }
 624}
 625
 626#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 627pub struct ExpandInfo {
 628    pub direction: ExpandExcerptDirection,
 629    pub excerpt_id: ExcerptId,
 630}
 631
 632#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 633pub struct RowInfo {
 634    pub buffer_id: Option<BufferId>,
 635    pub buffer_row: Option<u32>,
 636    pub multibuffer_row: Option<MultiBufferRow>,
 637    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 638    pub expand_info: Option<ExpandInfo>,
 639    pub wrapped_buffer_row: Option<u32>,
 640}
 641
 642/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 643#[derive(Clone)]
 644struct Excerpt {
 645    /// The unique identifier for this excerpt
 646    id: ExcerptId,
 647    /// The location of the excerpt in the [`MultiBuffer`]
 648    locator: Locator,
 649    /// The buffer being excerpted
 650    buffer_id: BufferId,
 651    /// A snapshot of the buffer being excerpted
 652    buffer: BufferSnapshot,
 653    /// The range of the buffer to be shown in the excerpt
 654    range: ExcerptRange<text::Anchor>,
 655    /// The last row in the excerpted slice of the buffer
 656    max_buffer_row: BufferRow,
 657    /// A summary of the text in the excerpt
 658    text_summary: TextSummary,
 659    has_trailing_newline: bool,
 660}
 661
 662/// A public view into an `Excerpt` in a [`MultiBuffer`].
 663///
 664/// Contains methods for getting the [`Buffer`] of the excerpt,
 665/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 666#[derive(Clone)]
 667pub struct MultiBufferExcerpt<'a> {
 668    excerpt: &'a Excerpt,
 669    diff_transforms:
 670        sum_tree::Cursor<'a, 'static, DiffTransform, DiffTransforms<MultiBufferOffset>>,
 671    offset: MultiBufferOffset,
 672    // todo unsure about this type
 673    excerpt_offset: MultiBufferOffset,
 674    buffer_offset: BufferOffset,
 675}
 676
 677#[derive(Clone, Debug)]
 678struct ExcerptIdMapping {
 679    id: ExcerptId,
 680    locator: Locator,
 681}
 682
 683/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 684/// These ranges are relative to the buffer itself
 685#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 686pub struct ExcerptRange<T> {
 687    /// The full range of text to be shown in the excerpt.
 688    pub context: Range<T>,
 689    /// The primary range of text to be highlighted in the excerpt.
 690    /// In a multi-buffer search, this would be the text that matched the search
 691    pub primary: Range<T>,
 692}
 693
 694impl<T: Clone> ExcerptRange<T> {
 695    pub fn new(context: Range<T>) -> Self {
 696        Self {
 697            context: context.clone(),
 698            primary: context,
 699        }
 700    }
 701}
 702
 703#[derive(Clone, Debug, Default)]
 704pub struct ExcerptSummary {
 705    excerpt_id: ExcerptId,
 706    /// The location of the last [`Excerpt`] being summarized
 707    excerpt_locator: Locator,
 708    widest_line_number: u32,
 709    text: MBTextSummary,
 710}
 711
 712#[derive(Debug, Clone)]
 713pub struct DiffTransformSummary {
 714    input: MBTextSummary,
 715    output: MBTextSummary,
 716}
 717
 718/// Summary of a string of text.
 719#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 720pub struct MBTextSummary {
 721    /// Length in bytes.
 722    pub len: MultiBufferOffset,
 723    /// Length in UTF-8.
 724    pub chars: usize,
 725    /// Length in UTF-16 code units
 726    pub len_utf16: OffsetUtf16,
 727    /// A point representing the number of lines and the length of the last line.
 728    ///
 729    /// In other words, it marks the point after the last byte in the text, (if
 730    /// EOF was a character, this would be its position).
 731    pub lines: Point,
 732    /// How many `char`s are in the first line
 733    pub first_line_chars: u32,
 734    /// How many `char`s are in the last line
 735    pub last_line_chars: u32,
 736    /// How many UTF-16 code units are in the last line
 737    pub last_line_len_utf16: u32,
 738    /// The row idx of the longest row
 739    pub longest_row: u32,
 740    /// How many `char`s are in the longest row
 741    pub longest_row_chars: u32,
 742}
 743
 744impl From<TextSummary> for MBTextSummary {
 745    fn from(summary: TextSummary) -> Self {
 746        MBTextSummary {
 747            len: MultiBufferOffset(summary.len),
 748            chars: summary.chars,
 749            len_utf16: summary.len_utf16,
 750            lines: summary.lines,
 751            first_line_chars: summary.first_line_chars,
 752            last_line_chars: summary.last_line_chars,
 753            last_line_len_utf16: summary.last_line_len_utf16,
 754            longest_row: summary.longest_row,
 755            longest_row_chars: summary.longest_row_chars,
 756        }
 757    }
 758}
 759impl From<&str> for MBTextSummary {
 760    fn from(text: &str) -> Self {
 761        MBTextSummary::from(TextSummary::from(text))
 762    }
 763}
 764
 765impl MultiBufferDimension for MBTextSummary {
 766    type TextDimension = TextSummary;
 767
 768    fn from_summary(summary: &MBTextSummary) -> Self {
 769        *summary
 770    }
 771
 772    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 773        *self += *summary;
 774    }
 775
 776    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 777        *self += *summary;
 778    }
 779}
 780
 781impl AddAssign for MBTextSummary {
 782    fn add_assign(&mut self, other: MBTextSummary) {
 783        let joined_chars = self.last_line_chars + other.first_line_chars;
 784        if joined_chars > self.longest_row_chars {
 785            self.longest_row = self.lines.row;
 786            self.longest_row_chars = joined_chars;
 787        }
 788        if other.longest_row_chars > self.longest_row_chars {
 789            self.longest_row = self.lines.row + other.longest_row;
 790            self.longest_row_chars = other.longest_row_chars;
 791        }
 792
 793        if self.lines.row == 0 {
 794            self.first_line_chars += other.first_line_chars;
 795        }
 796
 797        if other.lines.row == 0 {
 798            self.last_line_chars += other.first_line_chars;
 799            self.last_line_len_utf16 += other.last_line_len_utf16;
 800        } else {
 801            self.last_line_chars = other.last_line_chars;
 802            self.last_line_len_utf16 = other.last_line_len_utf16;
 803        }
 804
 805        self.chars += other.chars;
 806        self.len += other.len;
 807        self.len_utf16 += other.len_utf16;
 808        self.lines += other.lines;
 809    }
 810}
 811
 812impl AddAssign<TextSummary> for MBTextSummary {
 813    fn add_assign(&mut self, other: TextSummary) {
 814        *self += MBTextSummary::from(other);
 815    }
 816}
 817
 818impl MBTextSummary {
 819    pub fn lines_utf16(&self) -> PointUtf16 {
 820        PointUtf16 {
 821            row: self.lines.row,
 822            column: self.last_line_len_utf16,
 823        }
 824    }
 825}
 826
 827impl<K, V> MultiBufferDimension for DimensionPair<K, V>
 828where
 829    K: MultiBufferDimension,
 830    V: MultiBufferDimension,
 831{
 832    type TextDimension = DimensionPair<K::TextDimension, V::TextDimension>;
 833
 834    fn from_summary(summary: &MBTextSummary) -> Self {
 835        Self {
 836            key: K::from_summary(summary),
 837            value: Some(V::from_summary(summary)),
 838        }
 839    }
 840
 841    fn add_text_dim(&mut self, summary: &Self::TextDimension) {
 842        self.key.add_text_dim(&summary.key);
 843        if let Some(value) = &mut self.value {
 844            if let Some(other_value) = summary.value.as_ref() {
 845                value.add_text_dim(other_value);
 846            }
 847        }
 848    }
 849
 850    fn add_mb_text_summary(&mut self, summary: &MBTextSummary) {
 851        self.key.add_mb_text_summary(summary);
 852        if let Some(value) = &mut self.value {
 853            value.add_mb_text_summary(summary);
 854        }
 855    }
 856}
 857
 858#[derive(Clone)]
 859pub struct MultiBufferRows<'a> {
 860    point: Point,
 861    is_empty: bool,
 862    is_singleton: bool,
 863    cursor: MultiBufferCursor<'a, Point, Point>,
 864}
 865
 866pub struct MultiBufferChunks<'a> {
 867    excerpts: Cursor<'a, 'static, Excerpt, ExcerptOffset>,
 868    diff_transforms:
 869        Cursor<'a, 'static, DiffTransform, Dimensions<MultiBufferOffset, ExcerptOffset>>,
 870    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 871    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 872    buffer_chunk: Option<Chunk<'a>>,
 873    range: Range<MultiBufferOffset>,
 874    excerpt_offset_range: Range<ExcerptOffset>,
 875    excerpt_chunks: Option<ExcerptChunks<'a>>,
 876    language_aware: bool,
 877}
 878
 879pub struct ReversedMultiBufferChunks<'a> {
 880    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 881    current_chunks: Option<rope::Chunks<'a>>,
 882    start: MultiBufferOffset,
 883    offset: MultiBufferOffset,
 884}
 885
 886pub struct MultiBufferBytes<'a> {
 887    range: Range<MultiBufferOffset>,
 888    cursor: MultiBufferCursor<'a, MultiBufferOffset, BufferOffset>,
 889    excerpt_bytes: Option<text::Bytes<'a>>,
 890    has_trailing_newline: bool,
 891    chunk: &'a [u8],
 892}
 893
 894pub struct ReversedMultiBufferBytes<'a> {
 895    range: Range<MultiBufferOffset>,
 896    chunks: ReversedMultiBufferChunks<'a>,
 897    chunk: &'a [u8],
 898}
 899
 900#[derive(Clone)]
 901struct DiffTransforms<MBD> {
 902    output_dimension: OutputDimension<MBD>,
 903    excerpt_dimension: ExcerptDimension<MBD>,
 904}
 905
 906impl<'a, MBD: MultiBufferDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<MBD> {
 907    fn zero(cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>) -> Self {
 908        Self {
 909            output_dimension: OutputDimension::zero(cx),
 910            excerpt_dimension: <ExcerptDimension<MBD> as Dimension<'a, DiffTransformSummary>>::zero(
 911                cx,
 912            ),
 913        }
 914    }
 915
 916    fn add_summary(
 917        &mut self,
 918        summary: &'a DiffTransformSummary,
 919        cx: <DiffTransformSummary as sum_tree::Summary>::Context<'_>,
 920    ) {
 921        self.output_dimension.add_summary(summary, cx);
 922        self.excerpt_dimension.add_summary(summary, cx);
 923    }
 924}
 925
 926#[derive(Clone)]
 927struct MultiBufferCursor<'a, MBD, BD> {
 928    excerpts: Cursor<'a, 'static, Excerpt, ExcerptDimension<MBD>>,
 929    diff_transforms: Cursor<'a, 'static, DiffTransform, DiffTransforms<MBD>>,
 930    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 931    cached_region: Option<MultiBufferRegion<'a, MBD, BD>>,
 932}
 933
 934#[derive(Clone)]
 935struct MultiBufferRegion<'a, MBD, BD> {
 936    buffer: &'a BufferSnapshot,
 937    is_main_buffer: bool,
 938    diff_hunk_status: Option<DiffHunkStatus>,
 939    excerpt: &'a Excerpt,
 940    buffer_range: Range<BD>,
 941    range: Range<MBD>,
 942    has_trailing_newline: bool,
 943}
 944
 945struct ExcerptChunks<'a> {
 946    excerpt_id: ExcerptId,
 947    content_chunks: BufferChunks<'a>,
 948    has_footer: bool,
 949}
 950
 951#[derive(Debug)]
 952struct BufferEdit {
 953    range: Range<BufferOffset>,
 954    new_text: Arc<str>,
 955    is_insertion: bool,
 956    original_indent_column: Option<u32>,
 957    excerpt_id: ExcerptId,
 958}
 959
 960#[derive(Clone, Copy, Debug, PartialEq)]
 961enum DiffChangeKind {
 962    BufferEdited,
 963    DiffUpdated { base_changed: bool },
 964    ExpandOrCollapseHunks { expand: bool },
 965}
 966
 967#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 968pub enum ExpandExcerptDirection {
 969    Up,
 970    Down,
 971    UpAndDown,
 972}
 973
 974impl ExpandExcerptDirection {
 975    pub fn should_expand_up(&self) -> bool {
 976        match self {
 977            ExpandExcerptDirection::Up => true,
 978            ExpandExcerptDirection::Down => false,
 979            ExpandExcerptDirection::UpAndDown => true,
 980        }
 981    }
 982
 983    pub fn should_expand_down(&self) -> bool {
 984        match self {
 985            ExpandExcerptDirection::Up => false,
 986            ExpandExcerptDirection::Down => true,
 987            ExpandExcerptDirection::UpAndDown => true,
 988        }
 989    }
 990}
 991
 992#[derive(Clone, Debug, PartialEq)]
 993pub struct IndentGuide {
 994    pub buffer_id: BufferId,
 995    pub start_row: MultiBufferRow,
 996    pub end_row: MultiBufferRow,
 997    pub depth: u32,
 998    pub tab_size: u32,
 999    pub settings: IndentGuideSettings,
1000}
1001
1002impl IndentGuide {
1003    pub fn indent_level(&self) -> u32 {
1004        self.depth * self.tab_size
1005    }
1006}
1007
1008impl MultiBuffer {
1009    pub fn new(capability: Capability) -> Self {
1010        Self::new_(
1011            capability,
1012            MultiBufferSnapshot {
1013                show_headers: true,
1014                ..MultiBufferSnapshot::default()
1015            },
1016        )
1017    }
1018
1019    pub fn without_headers(capability: Capability) -> Self {
1020        Self::new_(capability, Default::default())
1021    }
1022
1023    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
1024        let mut this = Self::new_(
1025            buffer.read(cx).capability(),
1026            MultiBufferSnapshot {
1027                singleton: true,
1028                ..MultiBufferSnapshot::default()
1029            },
1030        );
1031        this.singleton = true;
1032        this.push_excerpts(
1033            buffer,
1034            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
1035            cx,
1036        );
1037        this
1038    }
1039
1040    #[inline]
1041    pub fn new_(capability: Capability, snapshot: MultiBufferSnapshot) -> Self {
1042        Self {
1043            snapshot: RefCell::new(snapshot),
1044            buffers: Default::default(),
1045            diffs: HashMap::default(),
1046            subscriptions: Topic::default(),
1047            singleton: false,
1048            capability,
1049            title: None,
1050            excerpts_by_path: Default::default(),
1051            paths_by_excerpt: Default::default(),
1052            buffer_changed_since_sync: Default::default(),
1053            history: History::default(),
1054        }
1055    }
1056
1057    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
1058        let mut buffers = HashMap::default();
1059        let buffer_changed_since_sync = Rc::new(Cell::new(false));
1060        for (buffer_id, buffer_state) in self.buffers.iter() {
1061            buffer_state.buffer.update(new_cx, |buffer, _| {
1062                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
1063            });
1064            buffers.insert(
1065                *buffer_id,
1066                BufferState {
1067                    buffer: buffer_state.buffer.clone(),
1068                    last_version: buffer_state.last_version.clone(),
1069                    last_non_text_state_update_count: buffer_state
1070                        .last_non_text_state_update_count
1071                        .clone(),
1072                    excerpts: buffer_state.excerpts.clone(),
1073                    _subscriptions: [
1074                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
1075                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
1076                    ],
1077                },
1078            );
1079        }
1080        let mut diff_bases = HashMap::default();
1081        for (buffer_id, diff) in self.diffs.iter() {
1082            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
1083        }
1084        Self {
1085            snapshot: RefCell::new(self.snapshot.borrow().clone()),
1086            buffers: buffers,
1087            excerpts_by_path: Default::default(),
1088            paths_by_excerpt: Default::default(),
1089            diffs: diff_bases,
1090            subscriptions: Default::default(),
1091            singleton: self.singleton,
1092            capability: self.capability,
1093            history: self.history.clone(),
1094            title: self.title.clone(),
1095            buffer_changed_since_sync,
1096        }
1097    }
1098
1099    pub fn set_group_interval(&mut self, group_interval: Duration) {
1100        self.history.set_group_interval(group_interval);
1101    }
1102
1103    pub fn with_title(mut self, title: String) -> Self {
1104        self.title = Some(title);
1105        self
1106    }
1107
1108    pub fn read_only(&self) -> bool {
1109        self.capability == Capability::ReadOnly
1110    }
1111
1112    /// Returns an up-to-date snapshot of the MultiBuffer.
1113    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
1114        self.sync(cx);
1115        self.snapshot.borrow().clone()
1116    }
1117
1118    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
1119        self.sync(cx);
1120        self.snapshot.borrow()
1121    }
1122
1123    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
1124        if self.singleton {
1125            Some(self.buffers.values().next().unwrap().buffer.clone())
1126        } else {
1127            None
1128        }
1129    }
1130
1131    pub fn is_singleton(&self) -> bool {
1132        self.singleton
1133    }
1134
1135    pub fn subscribe(&mut self) -> Subscription<MultiBufferOffset> {
1136        self.subscriptions.subscribe()
1137    }
1138
1139    pub fn is_dirty(&self, cx: &App) -> bool {
1140        self.read(cx).is_dirty()
1141    }
1142
1143    pub fn has_deleted_file(&self, cx: &App) -> bool {
1144        self.read(cx).has_deleted_file()
1145    }
1146
1147    pub fn has_conflict(&self, cx: &App) -> bool {
1148        self.read(cx).has_conflict()
1149    }
1150
1151    // The `is_empty` signature doesn't match what clippy expects
1152    #[allow(clippy::len_without_is_empty)]
1153    pub fn len(&self, cx: &App) -> MultiBufferOffset {
1154        self.read(cx).len()
1155    }
1156
1157    pub fn is_empty(&self) -> bool {
1158        self.buffers.is_empty()
1159    }
1160
1161    pub fn edit<I, S, T>(
1162        &mut self,
1163        edits: I,
1164        autoindent_mode: Option<AutoindentMode>,
1165        cx: &mut Context<Self>,
1166    ) where
1167        I: IntoIterator<Item = (Range<S>, T)>,
1168        S: ToOffset,
1169        T: Into<Arc<str>>,
1170    {
1171        if self.read_only() || self.buffers.is_empty() {
1172            return;
1173        }
1174        self.sync_mut(cx);
1175        let edits = edits
1176            .into_iter()
1177            .map(|(range, new_text)| {
1178                let mut range = range.start.to_offset(self.snapshot.get_mut())
1179                    ..range.end.to_offset(self.snapshot.get_mut());
1180                if range.start > range.end {
1181                    mem::swap(&mut range.start, &mut range.end);
1182                }
1183                (range, new_text.into())
1184            })
1185            .collect::<Vec<_>>();
1186
1187        return edit_internal(self, edits, autoindent_mode, cx);
1188
1189        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
1190        fn edit_internal(
1191            this: &mut MultiBuffer,
1192            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1193            mut autoindent_mode: Option<AutoindentMode>,
1194            cx: &mut Context<MultiBuffer>,
1195        ) {
1196            let original_indent_columns = match &mut autoindent_mode {
1197                Some(AutoindentMode::Block {
1198                    original_indent_columns,
1199                }) => mem::take(original_indent_columns),
1200                _ => Default::default(),
1201            };
1202
1203            let (buffer_edits, edited_excerpt_ids) = MultiBuffer::convert_edits_to_buffer_edits(
1204                edits,
1205                this.snapshot.get_mut(),
1206                &original_indent_columns,
1207            );
1208
1209            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
1210            for (buffer_id, mut edits) in buffer_edits {
1211                buffer_ids.push(buffer_id);
1212                edits.sort_by_key(|edit| edit.range.start);
1213                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1214                    let mut edits = edits.into_iter().peekable();
1215                    let mut insertions = Vec::new();
1216                    let mut original_indent_columns = Vec::new();
1217                    let mut deletions = Vec::new();
1218                    let empty_str: Arc<str> = Arc::default();
1219                    while let Some(BufferEdit {
1220                        mut range,
1221                        mut new_text,
1222                        mut is_insertion,
1223                        original_indent_column,
1224                        excerpt_id,
1225                    }) = edits.next()
1226                    {
1227                        while let Some(BufferEdit {
1228                            range: next_range,
1229                            is_insertion: next_is_insertion,
1230                            new_text: next_new_text,
1231                            excerpt_id: next_excerpt_id,
1232                            ..
1233                        }) = edits.peek()
1234                        {
1235                            if range.end >= next_range.start {
1236                                range.end = cmp::max(next_range.end, range.end);
1237                                is_insertion |= *next_is_insertion;
1238                                if excerpt_id == *next_excerpt_id {
1239                                    new_text = format!("{new_text}{next_new_text}").into();
1240                                }
1241                                edits.next();
1242                            } else {
1243                                break;
1244                            }
1245                        }
1246
1247                        if is_insertion {
1248                            original_indent_columns.push(original_indent_column);
1249                            insertions.push((
1250                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1251                                new_text.clone(),
1252                            ));
1253                        } else if !range.is_empty() {
1254                            deletions.push((
1255                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
1256                                empty_str.clone(),
1257                            ));
1258                        }
1259                    }
1260
1261                    let deletion_autoindent_mode =
1262                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1263                            Some(AutoindentMode::Block {
1264                                original_indent_columns: Default::default(),
1265                            })
1266                        } else {
1267                            autoindent_mode.clone()
1268                        };
1269                    let insertion_autoindent_mode =
1270                        if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
1271                            Some(AutoindentMode::Block {
1272                                original_indent_columns,
1273                            })
1274                        } else {
1275                            autoindent_mode.clone()
1276                        };
1277
1278                    buffer.edit(deletions, deletion_autoindent_mode, cx);
1279                    buffer.edit(insertions, insertion_autoindent_mode, cx);
1280                })
1281            }
1282
1283            cx.emit(Event::ExcerptsEdited {
1284                excerpt_ids: edited_excerpt_ids,
1285                buffer_ids,
1286            });
1287        }
1288    }
1289
1290    fn convert_edits_to_buffer_edits(
1291        edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1292        snapshot: &MultiBufferSnapshot,
1293        original_indent_columns: &[Option<u32>],
1294    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
1295        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
1296        let mut edited_excerpt_ids = Vec::new();
1297        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1298        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
1299            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
1300
1301            cursor.seek(&range.start);
1302            let mut start_region = cursor.region().expect("start offset out of bounds");
1303            if !start_region.is_main_buffer {
1304                cursor.next();
1305                if let Some(region) = cursor.region() {
1306                    start_region = region;
1307                } else {
1308                    continue;
1309                }
1310            }
1311
1312            if range.end < start_region.range.start {
1313                continue;
1314            }
1315
1316            if range.end > start_region.range.end {
1317                cursor.seek_forward(&range.end);
1318            }
1319            let mut end_region = cursor.region().expect("end offset out of bounds");
1320            if !end_region.is_main_buffer {
1321                cursor.prev();
1322                if let Some(region) = cursor.region() {
1323                    end_region = region;
1324                } else {
1325                    continue;
1326                }
1327            }
1328
1329            if range.start > end_region.range.end {
1330                continue;
1331            }
1332
1333            let start_overshoot = range.start.saturating_sub(start_region.range.start);
1334            let end_overshoot = range.end.saturating_sub(end_region.range.start);
1335            let buffer_start = (start_region.buffer_range.start + start_overshoot)
1336                .min(start_region.buffer_range.end);
1337            let buffer_end =
1338                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
1339
1340            if start_region.excerpt.id == end_region.excerpt.id {
1341                if start_region.is_main_buffer {
1342                    edited_excerpt_ids.push(start_region.excerpt.id);
1343                    buffer_edits
1344                        .entry(start_region.buffer.remote_id())
1345                        .or_default()
1346                        .push(BufferEdit {
1347                            range: buffer_start..buffer_end,
1348                            new_text,
1349                            is_insertion: true,
1350                            original_indent_column,
1351                            excerpt_id: start_region.excerpt.id,
1352                        });
1353                }
1354            } else {
1355                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
1356                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
1357                if start_region.is_main_buffer {
1358                    edited_excerpt_ids.push(start_region.excerpt.id);
1359                    buffer_edits
1360                        .entry(start_region.buffer.remote_id())
1361                        .or_default()
1362                        .push(BufferEdit {
1363                            range: start_excerpt_range,
1364                            new_text: new_text.clone(),
1365                            is_insertion: true,
1366                            original_indent_column,
1367                            excerpt_id: start_region.excerpt.id,
1368                        });
1369                }
1370                if end_region.is_main_buffer {
1371                    edited_excerpt_ids.push(end_region.excerpt.id);
1372                    buffer_edits
1373                        .entry(end_region.buffer.remote_id())
1374                        .or_default()
1375                        .push(BufferEdit {
1376                            range: end_excerpt_range,
1377                            new_text: new_text.clone(),
1378                            is_insertion: false,
1379                            original_indent_column,
1380                            excerpt_id: end_region.excerpt.id,
1381                        });
1382                }
1383
1384                cursor.seek(&range.start);
1385                cursor.next_excerpt();
1386                while let Some(region) = cursor.region() {
1387                    if region.excerpt.id == end_region.excerpt.id {
1388                        break;
1389                    }
1390                    if region.is_main_buffer {
1391                        edited_excerpt_ids.push(region.excerpt.id);
1392                        buffer_edits
1393                            .entry(region.buffer.remote_id())
1394                            .or_default()
1395                            .push(BufferEdit {
1396                                range: region.buffer_range,
1397                                new_text: new_text.clone(),
1398                                is_insertion: false,
1399                                original_indent_column,
1400                                excerpt_id: region.excerpt.id,
1401                            });
1402                    }
1403                    cursor.next_excerpt();
1404                }
1405            }
1406        }
1407        (buffer_edits, edited_excerpt_ids)
1408    }
1409
1410    pub fn autoindent_ranges<I, S>(&mut self, ranges: I, cx: &mut Context<Self>)
1411    where
1412        I: IntoIterator<Item = Range<S>>,
1413        S: ToOffset,
1414    {
1415        if self.read_only() || self.buffers.is_empty() {
1416            return;
1417        }
1418        self.sync_mut(cx);
1419        let empty = Arc::<str>::from("");
1420        let edits = ranges
1421            .into_iter()
1422            .map(|range| {
1423                let mut range = range.start.to_offset(self.snapshot.get_mut())
1424                    ..range.end.to_offset(&self.snapshot.get_mut());
1425                if range.start > range.end {
1426                    mem::swap(&mut range.start, &mut range.end);
1427                }
1428                (range, empty.clone())
1429            })
1430            .collect::<Vec<_>>();
1431
1432        return autoindent_ranges_internal(self, edits, cx);
1433
1434        fn autoindent_ranges_internal(
1435            this: &mut MultiBuffer,
1436            edits: Vec<(Range<MultiBufferOffset>, Arc<str>)>,
1437            cx: &mut Context<MultiBuffer>,
1438        ) {
1439            let (buffer_edits, edited_excerpt_ids) =
1440                MultiBuffer::convert_edits_to_buffer_edits(edits, this.snapshot.get_mut(), &[]);
1441
1442            let mut buffer_ids = Vec::new();
1443            for (buffer_id, mut edits) in buffer_edits {
1444                buffer_ids.push(buffer_id);
1445                edits.sort_unstable_by_key(|edit| edit.range.start);
1446
1447                let mut ranges: Vec<Range<BufferOffset>> = Vec::new();
1448                for edit in edits {
1449                    if let Some(last_range) = ranges.last_mut()
1450                        && edit.range.start <= last_range.end
1451                    {
1452                        last_range.end = last_range.end.max(edit.range.end);
1453                        continue;
1454                    }
1455                    ranges.push(edit.range);
1456                }
1457
1458                this.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1459                    buffer.autoindent_ranges(ranges, cx);
1460                })
1461            }
1462
1463            cx.emit(Event::ExcerptsEdited {
1464                excerpt_ids: edited_excerpt_ids,
1465                buffer_ids,
1466            });
1467        }
1468    }
1469
1470    /// Inserts newlines at the given position to create an empty line, returning the start of the new line.
1471    /// You can also request the insertion of empty lines above and below the line starting at the returned point.
1472    /// Panics if the given position is invalid.
1473    pub fn insert_empty_line(
1474        &mut self,
1475        position: impl ToPoint,
1476        space_above: bool,
1477        space_below: bool,
1478        cx: &mut Context<Self>,
1479    ) -> Point {
1480        let multibuffer_point = position.to_point(&self.read(cx));
1481        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1482        self.start_transaction(cx);
1483        let empty_line_start = buffer.update(cx, |buffer, cx| {
1484            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1485        });
1486        self.end_transaction(cx);
1487        multibuffer_point + (empty_line_start - buffer_point)
1488    }
1489
1490    pub fn set_active_selections(
1491        &self,
1492        selections: &[Selection<Anchor>],
1493        line_mode: bool,
1494        cursor_shape: CursorShape,
1495        cx: &mut Context<Self>,
1496    ) {
1497        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1498            Default::default();
1499        let snapshot = self.read(cx);
1500        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1501        for selection in selections {
1502            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1503            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1504
1505            cursor.seek(&Some(start_locator), Bias::Left);
1506            while let Some(excerpt) = cursor.item()
1507                && excerpt.locator <= *end_locator
1508            {
1509                let mut start = excerpt.range.context.start;
1510                let mut end = excerpt.range.context.end;
1511                if excerpt.id == selection.start.excerpt_id {
1512                    start = selection.start.text_anchor;
1513                }
1514                if excerpt.id == selection.end.excerpt_id {
1515                    end = selection.end.text_anchor;
1516                }
1517                selections_by_buffer
1518                    .entry(excerpt.buffer_id)
1519                    .or_default()
1520                    .push(Selection {
1521                        id: selection.id,
1522                        start,
1523                        end,
1524                        reversed: selection.reversed,
1525                        goal: selection.goal,
1526                    });
1527
1528                cursor.next();
1529            }
1530        }
1531
1532        for (buffer_id, buffer_state) in self.buffers.iter() {
1533            if !selections_by_buffer.contains_key(buffer_id) {
1534                buffer_state
1535                    .buffer
1536                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1537            }
1538        }
1539
1540        for (buffer_id, mut selections) in selections_by_buffer {
1541            self.buffers[&buffer_id].buffer.update(cx, |buffer, cx| {
1542                selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1543                let mut selections = selections.into_iter().peekable();
1544                let merged_selections = Arc::from_iter(iter::from_fn(|| {
1545                    let mut selection = selections.next()?;
1546                    while let Some(next_selection) = selections.peek() {
1547                        if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1548                            let next_selection = selections.next().unwrap();
1549                            if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1550                                selection.end = next_selection.end;
1551                            }
1552                        } else {
1553                            break;
1554                        }
1555                    }
1556                    Some(selection)
1557                }));
1558                buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1559            });
1560        }
1561    }
1562
1563    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1564        for buffer in self.buffers.values() {
1565            buffer
1566                .buffer
1567                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1568        }
1569    }
1570
1571    pub fn push_excerpts<O>(
1572        &mut self,
1573        buffer: Entity<Buffer>,
1574        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1575        cx: &mut Context<Self>,
1576    ) -> Vec<ExcerptId>
1577    where
1578        O: text::ToOffset,
1579    {
1580        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1581    }
1582
1583    fn merge_excerpt_ranges<'a>(
1584        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1585    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1586        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1587        let mut counts: Vec<usize> = Vec::new();
1588        for range in expanded_ranges {
1589            if let Some(last_range) = merged_ranges.last_mut() {
1590                assert!(
1591                    last_range.context.start <= range.context.start,
1592                    "ranges must be sorted: {last_range:?} <= {range:?}"
1593                );
1594                if last_range.context.end >= range.context.start
1595                    || last_range.context.end.row + 1 == range.context.start.row
1596                {
1597                    last_range.context.end = range.context.end.max(last_range.context.end);
1598                    *counts.last_mut().unwrap() += 1;
1599                    continue;
1600                }
1601            }
1602            merged_ranges.push(range.clone());
1603            counts.push(1);
1604        }
1605        (merged_ranges, counts)
1606    }
1607
1608    pub fn insert_excerpts_after<O>(
1609        &mut self,
1610        prev_excerpt_id: ExcerptId,
1611        buffer: Entity<Buffer>,
1612        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1613        cx: &mut Context<Self>,
1614    ) -> Vec<ExcerptId>
1615    where
1616        O: text::ToOffset,
1617    {
1618        let mut ids = Vec::new();
1619        let mut next_excerpt_id =
1620            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1621                last_entry.id.0 + 1
1622            } else {
1623                1
1624            };
1625        self.insert_excerpts_with_ids_after(
1626            prev_excerpt_id,
1627            buffer,
1628            ranges.into_iter().map(|range| {
1629                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1630                ids.push(id);
1631                (id, range)
1632            }),
1633            cx,
1634        );
1635        ids
1636    }
1637
1638    pub fn insert_excerpts_with_ids_after<O>(
1639        &mut self,
1640        prev_excerpt_id: ExcerptId,
1641        buffer: Entity<Buffer>,
1642        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1643        cx: &mut Context<Self>,
1644    ) where
1645        O: text::ToOffset,
1646    {
1647        assert_eq!(self.history.transaction_depth(), 0);
1648        let mut ranges = ranges.into_iter().peekable();
1649        if ranges.peek().is_none() {
1650            return Default::default();
1651        }
1652
1653        self.sync_mut(cx);
1654
1655        let buffer_snapshot = buffer.read(cx).snapshot();
1656        let buffer_id = buffer_snapshot.remote_id();
1657
1658        let buffer_state = self.buffers.entry(buffer_id).or_insert_with(|| {
1659            self.buffer_changed_since_sync.replace(true);
1660            buffer.update(cx, |buffer, _| {
1661                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1662            });
1663            BufferState {
1664                last_version: RefCell::new(buffer_snapshot.version().clone()),
1665                last_non_text_state_update_count: Cell::new(
1666                    buffer_snapshot.non_text_state_update_count(),
1667                ),
1668                excerpts: Default::default(),
1669                _subscriptions: [
1670                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1671                    cx.subscribe(&buffer, Self::on_buffer_event),
1672                ],
1673                buffer: buffer.clone(),
1674            }
1675        });
1676
1677        let mut snapshot = self.snapshot.get_mut();
1678
1679        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1680        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1681        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1682        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1683        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1684
1685        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len.0);
1686        new_excerpts.update_last(
1687            |excerpt| {
1688                excerpt.has_trailing_newline = true;
1689            },
1690            (),
1691        );
1692
1693        let next_locator = if let Some(excerpt) = cursor.item() {
1694            excerpt.locator.clone()
1695        } else {
1696            Locator::max()
1697        };
1698
1699        let mut excerpts = Vec::new();
1700        while let Some((id, range)) = ranges.next() {
1701            let locator = Locator::between(&prev_locator, &next_locator);
1702            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1703                buffer_state.excerpts.insert(ix, locator.clone());
1704            }
1705            let range = ExcerptRange {
1706                context: buffer_snapshot.anchor_before(&range.context.start)
1707                    ..buffer_snapshot.anchor_after(&range.context.end),
1708                primary: buffer_snapshot.anchor_before(&range.primary.start)
1709                    ..buffer_snapshot.anchor_after(&range.primary.end),
1710            };
1711            excerpts.push((id, range.clone()));
1712            let excerpt = Excerpt::new(
1713                id,
1714                locator.clone(),
1715                buffer_id,
1716                buffer_snapshot.clone(),
1717                range,
1718                ranges.peek().is_some() || cursor.item().is_some(),
1719            );
1720            new_excerpts.push(excerpt, ());
1721            prev_locator = locator.clone();
1722
1723            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
1724                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
1725            }
1726            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, ());
1727        }
1728
1729        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len.0);
1730
1731        let suffix = cursor.suffix();
1732        let changed_trailing_excerpt = suffix.is_empty();
1733        new_excerpts.append(suffix, ());
1734        drop(cursor);
1735        snapshot.excerpts = new_excerpts;
1736        snapshot.excerpt_ids = new_excerpt_ids;
1737        if changed_trailing_excerpt {
1738            snapshot.trailing_excerpt_update_count += 1;
1739        }
1740
1741        let edits = Self::sync_diff_transforms(
1742            &mut snapshot,
1743            vec![Edit {
1744                old: edit_start..edit_start,
1745                new: edit_start..edit_end,
1746            }],
1747            DiffChangeKind::BufferEdited,
1748        );
1749        if !edits.is_empty() {
1750            self.subscriptions.publish(edits);
1751        }
1752
1753        cx.emit(Event::Edited {
1754            edited_buffer: None,
1755        });
1756        cx.emit(Event::ExcerptsAdded {
1757            buffer,
1758            predecessor: prev_excerpt_id,
1759            excerpts,
1760        });
1761        cx.notify();
1762    }
1763
1764    pub fn clear(&mut self, cx: &mut Context<Self>) {
1765        self.sync_mut(cx);
1766        let ids = self.excerpt_ids();
1767        let removed_buffer_ids = self.buffers.drain().map(|(id, _)| id).collect();
1768        self.excerpts_by_path.clear();
1769        self.paths_by_excerpt.clear();
1770        let MultiBufferSnapshot {
1771            excerpts,
1772            diffs: _,
1773            diff_transforms: _,
1774            non_text_state_update_count: _,
1775            edit_count: _,
1776            is_dirty,
1777            has_deleted_file,
1778            has_conflict,
1779            singleton: _,
1780            excerpt_ids: _,
1781            replaced_excerpts,
1782            trailing_excerpt_update_count,
1783            all_diff_hunks_expanded: _,
1784            show_headers: _,
1785        } = self.snapshot.get_mut();
1786        let start = ExcerptOffset::new(0);
1787        let prev_len = ExcerptOffset::new(excerpts.summary().text.len.0);
1788        *excerpts = Default::default();
1789        *trailing_excerpt_update_count += 1;
1790        *is_dirty = false;
1791        *has_deleted_file = false;
1792        *has_conflict = false;
1793        replaced_excerpts.clear();
1794
1795        let edits = Self::sync_diff_transforms(
1796            self.snapshot.get_mut(),
1797            vec![Edit {
1798                old: start..prev_len,
1799                new: start..start,
1800            }],
1801            DiffChangeKind::BufferEdited,
1802        );
1803        if !edits.is_empty() {
1804            self.subscriptions.publish(edits);
1805        }
1806        cx.emit(Event::Edited {
1807            edited_buffer: None,
1808        });
1809        cx.emit(Event::ExcerptsRemoved {
1810            ids,
1811            removed_buffer_ids,
1812        });
1813        cx.notify();
1814    }
1815
1816    pub fn excerpts_for_buffer(
1817        &self,
1818        buffer_id: BufferId,
1819        cx: &App,
1820    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1821        let mut excerpts = Vec::new();
1822        let snapshot = self.read(cx);
1823        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(());
1824        if let Some(locators) = self.buffers.get(&buffer_id).map(|state| &state.excerpts) {
1825            for locator in locators {
1826                cursor.seek_forward(&Some(locator), Bias::Left);
1827                if let Some(excerpt) = cursor.item()
1828                    && excerpt.locator == *locator
1829                {
1830                    excerpts.push((excerpt.id, excerpt.range.clone()));
1831                }
1832            }
1833        }
1834
1835        excerpts
1836    }
1837
1838    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
1839        let snapshot = self.read(cx);
1840        let mut excerpts = snapshot
1841            .excerpts
1842            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
1843        let mut diff_transforms = snapshot
1844            .diff_transforms
1845            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
1846        diff_transforms.next();
1847        let locators = self
1848            .buffers
1849            .get(&buffer_id)
1850            .into_iter()
1851            .flat_map(|state| &state.excerpts);
1852        let mut result = Vec::new();
1853        for locator in locators {
1854            excerpts.seek_forward(&Some(locator), Bias::Left);
1855            if let Some(excerpt) = excerpts.item()
1856                && excerpt.locator == *locator
1857            {
1858                let excerpt_start = excerpts.start().1;
1859                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
1860
1861                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
1862                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
1863                let start = diff_transforms.start().1.0 + overshoot;
1864
1865                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
1866                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
1867                let end = diff_transforms.start().1.0 + overshoot;
1868
1869                result.push(start..end)
1870            }
1871        }
1872        result
1873    }
1874
1875    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
1876        self.snapshot
1877            .borrow()
1878            .excerpts
1879            .iter()
1880            .map(|entry| entry.buffer_id)
1881            .collect()
1882    }
1883
1884    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1885        self.snapshot
1886            .borrow()
1887            .excerpts
1888            .iter()
1889            .map(|entry| entry.id)
1890            .collect()
1891    }
1892
1893    pub fn excerpt_containing(
1894        &self,
1895        position: impl ToOffset,
1896        cx: &App,
1897    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
1898        let snapshot = self.read(cx);
1899        let offset = position.to_offset(&snapshot);
1900
1901        let mut cursor = snapshot.cursor::<MultiBufferOffset, BufferOffset>();
1902        cursor.seek(&offset);
1903        cursor
1904            .excerpt()
1905            .or_else(|| snapshot.excerpts.last())
1906            .map(|excerpt| {
1907                (
1908                    excerpt.id,
1909                    self.buffers.get(&excerpt.buffer_id).unwrap().buffer.clone(),
1910                    excerpt.range.context.clone(),
1911                )
1912            })
1913    }
1914
1915    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
1916        if let Some(buffer_id) = anchor.buffer_id {
1917            self.buffer(buffer_id)
1918        } else {
1919            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
1920            Some(buffer)
1921        }
1922    }
1923
1924    // If point is at the end of the buffer, the last excerpt is returned
1925    pub fn point_to_buffer_offset<T: ToOffset>(
1926        &self,
1927        point: T,
1928        cx: &App,
1929    ) -> Option<(Entity<Buffer>, BufferOffset)> {
1930        let snapshot = self.read(cx);
1931        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
1932        Some((
1933            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1934            offset,
1935        ))
1936    }
1937
1938    // If point is at the end of the buffer, the last excerpt is returned
1939    pub fn point_to_buffer_point<T: ToPoint>(
1940        &self,
1941        point: T,
1942        cx: &App,
1943    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
1944        let snapshot = self.read(cx);
1945        let (buffer, point, is_main_buffer) =
1946            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
1947        Some((
1948            self.buffers.get(&buffer.remote_id())?.buffer.clone(),
1949            point,
1950            is_main_buffer,
1951        ))
1952    }
1953
1954    pub fn buffer_point_to_anchor(
1955        &self,
1956        buffer: &Entity<Buffer>,
1957        point: Point,
1958        cx: &App,
1959    ) -> Option<Anchor> {
1960        let mut found = None;
1961        let snapshot = buffer.read(cx).snapshot();
1962        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1963            let start = range.context.start.to_point(&snapshot);
1964            let end = range.context.end.to_point(&snapshot);
1965            if start <= point && point < end {
1966                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
1967                break;
1968            }
1969            if point < start {
1970                found = Some((start, excerpt_id));
1971            }
1972            if point > end {
1973                found = Some((end, excerpt_id));
1974            }
1975        }
1976
1977        found.map(|(point, excerpt_id)| {
1978            let text_anchor = snapshot.anchor_after(point);
1979            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
1980        })
1981    }
1982
1983    pub fn buffer_anchor_to_anchor(
1984        &self,
1985        buffer: &Entity<Buffer>,
1986        anchor: text::Anchor,
1987        cx: &App,
1988    ) -> Option<Anchor> {
1989        let snapshot = buffer.read(cx).snapshot();
1990        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
1991            if range.context.start.cmp(&anchor, &snapshot).is_le()
1992                && range.context.end.cmp(&anchor, &snapshot).is_ge()
1993            {
1994                return Some(Anchor::in_buffer(excerpt_id, snapshot.remote_id(), anchor));
1995            }
1996        }
1997
1998        None
1999    }
2000
2001    pub fn remove_excerpts(
2002        &mut self,
2003        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2004        cx: &mut Context<Self>,
2005    ) {
2006        self.sync_mut(cx);
2007        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2008        if ids.is_empty() {
2009            return;
2010        }
2011        self.buffer_changed_since_sync.replace(true);
2012
2013        let mut snapshot = self.snapshot.get_mut();
2014        let mut new_excerpts = SumTree::default();
2015        let mut cursor = snapshot
2016            .excerpts
2017            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2018        let mut edits = Vec::new();
2019        let mut excerpt_ids = ids.iter().copied().peekable();
2020        let mut removed_buffer_ids = Vec::new();
2021
2022        while let Some(excerpt_id) = excerpt_ids.next() {
2023            self.paths_by_excerpt.remove(&excerpt_id);
2024            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2025            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2026            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2027
2028            if let Some(mut excerpt) = cursor.item() {
2029                if excerpt.id != excerpt_id {
2030                    continue;
2031                }
2032                let mut old_start = cursor.start().1;
2033
2034                // Skip over the removed excerpt.
2035                'remove_excerpts: loop {
2036                    if let Some(buffer_state) = self.buffers.get_mut(&excerpt.buffer_id) {
2037                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2038                        if buffer_state.excerpts.is_empty() {
2039                            log::debug!(
2040                                "removing buffer and diff for buffer {}",
2041                                excerpt.buffer_id
2042                            );
2043                            self.buffers.remove(&excerpt.buffer_id);
2044                            removed_buffer_ids.push(excerpt.buffer_id);
2045                        }
2046                    }
2047                    cursor.next();
2048
2049                    // Skip over any subsequent excerpts that are also removed.
2050                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2051                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2052                        if let Some(next_excerpt) = cursor.item()
2053                            && next_excerpt.locator == *next_locator
2054                        {
2055                            excerpt_ids.next();
2056                            excerpt = next_excerpt;
2057                            continue 'remove_excerpts;
2058                        }
2059                    }
2060
2061                    break;
2062                }
2063
2064                // When removing the last excerpt, remove the trailing newline from
2065                // the previous excerpt.
2066                if cursor.item().is_none() && old_start.value > 0 {
2067                    old_start.value -= 1;
2068                    new_excerpts.update_last(|e| e.has_trailing_newline = false, ());
2069                }
2070
2071                // Push an edit for the removal of this run of excerpts.
2072                let old_end = cursor.start().1;
2073                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len.0);
2074                edits.push(Edit {
2075                    old: old_start..old_end,
2076                    new: new_start..new_start,
2077                });
2078            }
2079        }
2080        let suffix = cursor.suffix();
2081        let changed_trailing_excerpt = suffix.is_empty();
2082        new_excerpts.append(suffix, ());
2083        drop(cursor);
2084        snapshot.excerpts = new_excerpts;
2085        for buffer_id in &removed_buffer_ids {
2086            self.diffs.remove(buffer_id);
2087            snapshot.diffs.remove(buffer_id);
2088        }
2089
2090        if changed_trailing_excerpt {
2091            snapshot.trailing_excerpt_update_count += 1;
2092        }
2093
2094        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2095        if !edits.is_empty() {
2096            self.subscriptions.publish(edits);
2097        }
2098        cx.emit(Event::Edited {
2099            edited_buffer: None,
2100        });
2101        cx.emit(Event::ExcerptsRemoved {
2102            ids,
2103            removed_buffer_ids,
2104        });
2105        cx.notify();
2106    }
2107
2108    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2109        &self,
2110        anchors: Anchors,
2111        cx: &mut Context<Self>,
2112    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2113        let mut error = None;
2114        let mut futures = Vec::new();
2115        for anchor in anchors {
2116            if let Some(buffer_id) = anchor.buffer_id {
2117                if let Some(buffer) = self.buffers.get(&buffer_id) {
2118                    buffer.buffer.update(cx, |buffer, _| {
2119                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2120                    });
2121                } else {
2122                    error = Some(anyhow!(
2123                        "buffer {buffer_id} is not part of this multi-buffer"
2124                    ));
2125                    break;
2126                }
2127            }
2128        }
2129        async move {
2130            if let Some(error) = error {
2131                Err(error)?;
2132            }
2133            for future in futures {
2134                future.await?;
2135            }
2136            Ok(())
2137        }
2138    }
2139
2140    pub fn text_anchor_for_position<T: ToOffset>(
2141        &self,
2142        position: T,
2143        cx: &App,
2144    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2145        let snapshot = self.read(cx);
2146        let anchor = snapshot.anchor_before(position);
2147        let buffer = self.buffers.get(&anchor.buffer_id?)?.buffer.clone();
2148        Some((buffer, anchor.text_anchor))
2149    }
2150
2151    fn on_buffer_event(
2152        &mut self,
2153        buffer: Entity<Buffer>,
2154        event: &language::BufferEvent,
2155        cx: &mut Context<Self>,
2156    ) {
2157        use language::BufferEvent;
2158        cx.emit(match event {
2159            BufferEvent::Edited => Event::Edited {
2160                edited_buffer: Some(buffer),
2161            },
2162            BufferEvent::DirtyChanged => Event::DirtyChanged,
2163            BufferEvent::Saved => Event::Saved,
2164            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2165            BufferEvent::Reloaded => Event::Reloaded,
2166            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
2167            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2168            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2169            BufferEvent::CapabilityChanged => {
2170                self.capability = buffer.read(cx).capability();
2171                return;
2172            }
2173            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2174        });
2175    }
2176
2177    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2178        let diff = diff.read(cx);
2179        let buffer_id = diff.buffer_id;
2180        let diff = diff.snapshot(cx);
2181        self.snapshot.get_mut().diffs.insert(buffer_id, diff);
2182    }
2183
2184    fn buffer_diff_changed(
2185        &mut self,
2186        diff: Entity<BufferDiff>,
2187        range: Range<text::Anchor>,
2188        cx: &mut Context<Self>,
2189    ) {
2190        self.sync_mut(cx);
2191
2192        let diff = diff.read(cx);
2193        let buffer_id = diff.buffer_id;
2194        let Some(buffer_state) = self.buffers.get(&buffer_id) else {
2195            return;
2196        };
2197        self.buffer_changed_since_sync.replace(true);
2198
2199        let buffer = buffer_state.buffer.read(cx);
2200        let diff_change_range = range.to_offset(buffer);
2201
2202        let new_diff = diff.snapshot(cx);
2203        let mut snapshot = self.snapshot.get_mut();
2204        let base_text_changed = snapshot
2205            .diffs
2206            .get(&buffer_id)
2207            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2208
2209        snapshot.diffs.insert(buffer_id, new_diff);
2210
2211        let mut excerpt_edits = Vec::new();
2212        for locator in &buffer_state.excerpts {
2213            let mut cursor = snapshot
2214                .excerpts
2215                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2216            cursor.seek_forward(&Some(locator), Bias::Left);
2217            if let Some(excerpt) = cursor.item()
2218                && excerpt.locator == *locator
2219            {
2220                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2221                if diff_change_range.end < excerpt_buffer_range.start
2222                    || diff_change_range.start > excerpt_buffer_range.end
2223                {
2224                    continue;
2225                }
2226                let excerpt_start = cursor.start().1;
2227                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2228                let diff_change_start_in_excerpt = ExcerptOffset::new(
2229                    diff_change_range
2230                        .start
2231                        .saturating_sub(excerpt_buffer_range.start),
2232                );
2233                let diff_change_end_in_excerpt = ExcerptOffset::new(
2234                    diff_change_range
2235                        .end
2236                        .saturating_sub(excerpt_buffer_range.start),
2237                );
2238                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2239                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2240                excerpt_edits.push(Edit {
2241                    old: edit_start..edit_end,
2242                    new: edit_start..edit_end,
2243                });
2244            }
2245        }
2246
2247        let edits = Self::sync_diff_transforms(
2248            &mut snapshot,
2249            excerpt_edits,
2250            DiffChangeKind::DiffUpdated {
2251                base_changed: base_text_changed,
2252            },
2253        );
2254        if !edits.is_empty() {
2255            self.subscriptions.publish(edits);
2256        }
2257        cx.emit(Event::Edited {
2258            edited_buffer: None,
2259        });
2260    }
2261
2262    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2263        self.buffers
2264            .values()
2265            .map(|state| state.buffer.clone())
2266            .collect()
2267    }
2268
2269    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2270        self.buffers.keys().copied().collect()
2271    }
2272
2273    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2274        self.buffers
2275            .get(&buffer_id)
2276            .map(|state| state.buffer.clone())
2277    }
2278
2279    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2280        self.point_to_buffer_offset(point, cx)
2281            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2282    }
2283
2284    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2285        let buffer_id = self
2286            .snapshot
2287            .borrow()
2288            .excerpts
2289            .first()
2290            .map(|excerpt| excerpt.buffer.remote_id());
2291        buffer_id
2292            .and_then(|buffer_id| self.buffer(buffer_id))
2293            .map(|buffer| {
2294                let buffer = buffer.read(cx);
2295                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2296            })
2297            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::default(), cx))
2298    }
2299
2300    pub fn language_settings_at<'a, T: ToOffset>(
2301        &'a self,
2302        point: T,
2303        cx: &'a App,
2304    ) -> Cow<'a, LanguageSettings> {
2305        let mut language = None;
2306        let mut file = None;
2307        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2308            let buffer = buffer.read(cx);
2309            language = buffer.language_at(offset);
2310            file = buffer.file();
2311        }
2312        language_settings(language.map(|l| l.name()), file, cx)
2313    }
2314
2315    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2316        self.buffers.values().for_each(|state| f(&state.buffer))
2317    }
2318
2319    pub fn explicit_title(&self) -> Option<&str> {
2320        self.title.as_deref()
2321    }
2322
2323    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2324        if let Some(title) = self.title.as_ref() {
2325            return title.into();
2326        }
2327
2328        if let Some(buffer) = self.as_singleton() {
2329            let buffer = buffer.read(cx);
2330
2331            if let Some(file) = buffer.file() {
2332                return file.file_name(cx).into();
2333            }
2334
2335            if let Some(title) = self.buffer_content_title(buffer) {
2336                return title;
2337            }
2338        };
2339
2340        "untitled".into()
2341    }
2342
2343    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2344        let mut is_leading_whitespace = true;
2345        let mut count = 0;
2346        let mut prev_was_space = false;
2347        let mut title = String::new();
2348
2349        for ch in buffer.snapshot().chars() {
2350            if is_leading_whitespace && ch.is_whitespace() {
2351                continue;
2352            }
2353
2354            is_leading_whitespace = false;
2355
2356            if ch == '\n' || count >= 40 {
2357                break;
2358            }
2359
2360            if ch.is_whitespace() {
2361                if !prev_was_space {
2362                    title.push(' ');
2363                    count += 1;
2364                    prev_was_space = true;
2365                }
2366            } else {
2367                title.push(ch);
2368                count += 1;
2369                prev_was_space = false;
2370            }
2371        }
2372
2373        let title = title.trim_end().to_string();
2374
2375        if title.is_empty() {
2376            return None;
2377        }
2378
2379        Some(title.into())
2380    }
2381
2382    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2383        self.title = Some(title);
2384        cx.notify();
2385    }
2386
2387    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2388    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2389        for buffer_state in self.buffers.values() {
2390            buffer_state
2391                .buffer
2392                .update(cx, |buffer, _cx| buffer.refresh_preview());
2393        }
2394    }
2395
2396    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2397    pub fn preserve_preview(&self, cx: &App) -> bool {
2398        self.buffers
2399            .values()
2400            .all(|state| state.buffer.read(cx).preserve_preview())
2401    }
2402
2403    #[cfg(any(test, feature = "test-support"))]
2404    pub fn is_parsing(&self, cx: &App) -> bool {
2405        self.as_singleton().unwrap().read(cx).is_parsing()
2406    }
2407
2408    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2409        let buffer_id = diff.read(cx).buffer_id;
2410        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2411        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2412    }
2413
2414    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2415        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2416    }
2417
2418    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2419        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2420    }
2421
2422    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2423        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2424    }
2425
2426    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2427        self.snapshot.get_mut().all_diff_hunks_expanded = true;
2428        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2429    }
2430
2431    pub fn all_diff_hunks_expanded(&self) -> bool {
2432        self.snapshot.borrow().all_diff_hunks_expanded
2433    }
2434
2435    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2436        self.snapshot.get_mut().all_diff_hunks_expanded = false;
2437        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2438    }
2439
2440    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2441        self.read(cx)
2442            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2443            .nth(1)
2444            .is_some()
2445    }
2446
2447    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2448        let snapshot = self.read(cx);
2449        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2450        let offset_range = range.to_offset(&snapshot);
2451        cursor.seek(&offset_range.start, Bias::Left);
2452        while let Some(item) = cursor.item() {
2453            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2454                break;
2455            }
2456            if item.hunk_info().is_some() {
2457                return true;
2458            }
2459            cursor.next();
2460        }
2461        false
2462    }
2463
2464    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2465        let snapshot = self.read(cx);
2466        let mut cursor = snapshot.diff_transforms.cursor::<MultiBufferOffset>(());
2467        for range in ranges {
2468            let range = range.to_point(&snapshot);
2469            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2470            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2471            let start = start.saturating_sub_usize(1);
2472            let end = snapshot.len().min(end + 1usize);
2473            cursor.seek(&start, Bias::Right);
2474            while let Some(item) = cursor.item() {
2475                if *cursor.start() >= end {
2476                    break;
2477                }
2478                if item.hunk_info().is_some() {
2479                    return true;
2480                }
2481                cursor.next();
2482            }
2483        }
2484        false
2485    }
2486
2487    pub fn expand_or_collapse_diff_hunks_inner(
2488        &mut self,
2489        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2490        expand: bool,
2491        cx: &mut Context<Self>,
2492    ) {
2493        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2494            return;
2495        }
2496        self.sync_mut(cx);
2497        let mut snapshot = self.snapshot.get_mut();
2498        let mut excerpt_edits = Vec::new();
2499        let mut last_hunk_row = None;
2500        for (range, end_excerpt_id) in ranges {
2501            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2502                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2503                    continue;
2504                }
2505                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2506                    continue;
2507                }
2508                let start = Anchor::in_buffer(
2509                    diff_hunk.excerpt_id,
2510                    diff_hunk.buffer_id,
2511                    diff_hunk.buffer_range.start,
2512                );
2513                let end = Anchor::in_buffer(
2514                    diff_hunk.excerpt_id,
2515                    diff_hunk.buffer_id,
2516                    diff_hunk.buffer_range.end,
2517                );
2518                let start = snapshot.excerpt_offset_for_anchor(&start);
2519                let end = snapshot.excerpt_offset_for_anchor(&end);
2520                last_hunk_row = Some(diff_hunk.row_range.start);
2521                excerpt_edits.push(text::Edit {
2522                    old: start..end,
2523                    new: start..end,
2524                });
2525            }
2526        }
2527
2528        let edits = Self::sync_diff_transforms(
2529            &mut snapshot,
2530            excerpt_edits,
2531            DiffChangeKind::ExpandOrCollapseHunks { expand },
2532        );
2533        if !edits.is_empty() {
2534            self.subscriptions.publish(edits);
2535        }
2536        cx.emit(Event::DiffHunksToggled);
2537        cx.emit(Event::Edited {
2538            edited_buffer: None,
2539        });
2540    }
2541
2542    pub fn expand_or_collapse_diff_hunks(
2543        &mut self,
2544        ranges: Vec<Range<Anchor>>,
2545        expand: bool,
2546        cx: &mut Context<Self>,
2547    ) {
2548        let snapshot = self.snapshot.borrow().clone();
2549        let ranges = ranges.iter().map(move |range| {
2550            let end_excerpt_id = range.end.excerpt_id;
2551            let range = range.to_point(&snapshot);
2552            let mut peek_end = range.end;
2553            if range.end.row < snapshot.max_row().0 {
2554                peek_end = Point::new(range.end.row + 1, 0);
2555            };
2556            (range.start..peek_end, end_excerpt_id)
2557        });
2558        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2559    }
2560
2561    pub fn resize_excerpt(
2562        &mut self,
2563        id: ExcerptId,
2564        range: Range<text::Anchor>,
2565        cx: &mut Context<Self>,
2566    ) {
2567        self.sync_mut(cx);
2568
2569        let mut snapshot = self.snapshot.get_mut();
2570        let locator = snapshot.excerpt_locator_for_id(id);
2571        let mut new_excerpts = SumTree::default();
2572        let mut cursor = snapshot
2573            .excerpts
2574            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2575        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2576
2577        let prefix = cursor.slice(&Some(locator), Bias::Left);
2578        new_excerpts.append(prefix, ());
2579
2580        let mut excerpt = cursor.item().unwrap().clone();
2581        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2582
2583        excerpt.range.context.start = range.start;
2584        excerpt.range.context.end = range.end;
2585        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2586
2587        excerpt.text_summary = excerpt
2588            .buffer
2589            .text_summary_for_range(excerpt.range.context.clone());
2590
2591        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len.0);
2592        let old_start_offset = cursor.start().1;
2593        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2594        let edit = Edit {
2595            old: old_start_offset..old_start_offset + old_text_len,
2596            new: new_start_offset..new_start_offset + new_text_len,
2597        };
2598
2599        if let Some(last_edit) = edits.last_mut() {
2600            if last_edit.old.end == edit.old.start {
2601                last_edit.old.end = edit.old.end;
2602                last_edit.new.end = edit.new.end;
2603            } else {
2604                edits.push(edit);
2605            }
2606        } else {
2607            edits.push(edit);
2608        }
2609
2610        new_excerpts.push(excerpt, ());
2611
2612        cursor.next();
2613
2614        new_excerpts.append(cursor.suffix(), ());
2615
2616        drop(cursor);
2617        snapshot.excerpts = new_excerpts;
2618
2619        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2620        if !edits.is_empty() {
2621            self.subscriptions.publish(edits);
2622        }
2623        cx.emit(Event::Edited {
2624            edited_buffer: None,
2625        });
2626        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2627        cx.notify();
2628    }
2629
2630    pub fn expand_excerpts(
2631        &mut self,
2632        ids: impl IntoIterator<Item = ExcerptId>,
2633        line_count: u32,
2634        direction: ExpandExcerptDirection,
2635        cx: &mut Context<Self>,
2636    ) {
2637        if line_count == 0 {
2638            return;
2639        }
2640        self.sync_mut(cx);
2641        if !self.excerpts_by_path.is_empty() {
2642            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2643            return;
2644        }
2645        let mut snapshot = self.snapshot.get_mut();
2646
2647        let ids = ids.into_iter().collect::<Vec<_>>();
2648        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2649        let mut new_excerpts = SumTree::default();
2650        let mut cursor = snapshot
2651            .excerpts
2652            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2653        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2654
2655        for locator in &locators {
2656            let prefix = cursor.slice(&Some(locator), Bias::Left);
2657            new_excerpts.append(prefix, ());
2658
2659            let mut excerpt = cursor.item().unwrap().clone();
2660            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2661
2662            let up_line_count = if direction.should_expand_up() {
2663                line_count
2664            } else {
2665                0
2666            };
2667
2668            let start_row = excerpt
2669                .range
2670                .context
2671                .start
2672                .to_point(&excerpt.buffer)
2673                .row
2674                .saturating_sub(up_line_count);
2675            let start_point = Point::new(start_row, 0);
2676            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2677
2678            let down_line_count = if direction.should_expand_down() {
2679                line_count
2680            } else {
2681                0
2682            };
2683
2684            let mut end_point = excerpt.buffer.clip_point(
2685                excerpt.range.context.end.to_point(&excerpt.buffer)
2686                    + Point::new(down_line_count, 0),
2687                Bias::Left,
2688            );
2689            end_point.column = excerpt.buffer.line_len(end_point.row);
2690            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2691            excerpt.max_buffer_row = end_point.row;
2692
2693            excerpt.text_summary = excerpt
2694                .buffer
2695                .text_summary_for_range(excerpt.range.context.clone());
2696
2697            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len.0);
2698            let old_start_offset = cursor.start().1;
2699            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2700            let edit = Edit {
2701                old: old_start_offset..old_start_offset + old_text_len,
2702                new: new_start_offset..new_start_offset + new_text_len,
2703            };
2704
2705            if let Some(last_edit) = edits.last_mut() {
2706                if last_edit.old.end == edit.old.start {
2707                    last_edit.old.end = edit.old.end;
2708                    last_edit.new.end = edit.new.end;
2709                } else {
2710                    edits.push(edit);
2711                }
2712            } else {
2713                edits.push(edit);
2714            }
2715
2716            new_excerpts.push(excerpt, ());
2717
2718            cursor.next();
2719        }
2720
2721        new_excerpts.append(cursor.suffix(), ());
2722
2723        drop(cursor);
2724        snapshot.excerpts = new_excerpts;
2725
2726        let edits = Self::sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2727        if !edits.is_empty() {
2728            self.subscriptions.publish(edits);
2729        }
2730        cx.emit(Event::Edited {
2731            edited_buffer: None,
2732        });
2733        cx.emit(Event::ExcerptsExpanded { ids });
2734        cx.notify();
2735    }
2736
2737    fn sync(&self, cx: &App) {
2738        let changed = self.buffer_changed_since_sync.replace(false);
2739        if !changed {
2740            return;
2741        }
2742        let edits = Self::sync_(
2743            &mut self.snapshot.borrow_mut(),
2744            &self.buffers,
2745            &self.diffs,
2746            cx,
2747        );
2748        if !edits.is_empty() {
2749            self.subscriptions.publish(edits);
2750        }
2751    }
2752
2753    fn sync_mut(&mut self, cx: &App) {
2754        let changed = self.buffer_changed_since_sync.replace(false);
2755        if !changed {
2756            return;
2757        }
2758        let edits = Self::sync_(self.snapshot.get_mut(), &self.buffers, &self.diffs, cx);
2759
2760        if !edits.is_empty() {
2761            self.subscriptions.publish(edits);
2762        }
2763    }
2764
2765    fn sync_(
2766        snapshot: &mut MultiBufferSnapshot,
2767        buffers: &HashMap<BufferId, BufferState>,
2768        diffs: &HashMap<BufferId, DiffState>,
2769        cx: &App,
2770    ) -> Vec<Edit<MultiBufferOffset>> {
2771        let MultiBufferSnapshot {
2772            excerpts,
2773            diffs: buffer_diff,
2774            diff_transforms: _,
2775            non_text_state_update_count,
2776            edit_count,
2777            is_dirty,
2778            has_deleted_file,
2779            has_conflict,
2780            singleton: _,
2781            excerpt_ids: _,
2782            replaced_excerpts: _,
2783            trailing_excerpt_update_count: _,
2784            all_diff_hunks_expanded: _,
2785            show_headers: _,
2786        } = snapshot;
2787        *is_dirty = false;
2788        *has_deleted_file = false;
2789        *has_conflict = false;
2790
2791        let mut excerpts_to_edit = Vec::new();
2792        let mut non_text_state_updated = false;
2793        let mut edited = false;
2794        for buffer_state in buffers.values() {
2795            let buffer = buffer_state.buffer.read(cx);
2796            let version = buffer.version();
2797            let non_text_state_update_count = buffer.non_text_state_update_count();
2798
2799            let buffer_edited = version.changed_since(&buffer_state.last_version.borrow());
2800            let buffer_non_text_state_updated =
2801                non_text_state_update_count > buffer_state.last_non_text_state_update_count.get();
2802            if buffer_edited || buffer_non_text_state_updated {
2803                *buffer_state.last_version.borrow_mut() = version;
2804                buffer_state
2805                    .last_non_text_state_update_count
2806                    .set(non_text_state_update_count);
2807                excerpts_to_edit.extend(
2808                    buffer_state
2809                        .excerpts
2810                        .iter()
2811                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2812                );
2813            }
2814
2815            edited |= buffer_edited;
2816            non_text_state_updated |= buffer_non_text_state_updated;
2817            *is_dirty |= buffer.is_dirty();
2818            *has_deleted_file |= buffer
2819                .file()
2820                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
2821            *has_conflict |= buffer.has_conflict();
2822        }
2823        if edited {
2824            *edit_count += 1;
2825        }
2826        if non_text_state_updated {
2827            *non_text_state_update_count += 1;
2828        }
2829
2830        for (id, diff) in diffs.iter() {
2831            if buffer_diff.get(id).is_none() {
2832                buffer_diff.insert(*id, diff.diff.read(cx).snapshot(cx));
2833            }
2834        }
2835
2836        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2837
2838        let mut edits = Vec::new();
2839        let mut new_excerpts = SumTree::default();
2840        let mut cursor = excerpts.cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
2841
2842        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2843            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), ());
2844            let old_excerpt = cursor.item().unwrap();
2845            let buffer = buffer.read(cx);
2846            let buffer_id = buffer.remote_id();
2847
2848            let mut new_excerpt;
2849            if buffer_edited {
2850                edits.extend(
2851                    buffer
2852                        .edits_since_in_range::<usize>(
2853                            old_excerpt.buffer.version(),
2854                            old_excerpt.range.context.clone(),
2855                        )
2856                        .map(|edit| {
2857                            let excerpt_old_start = cursor.start().1;
2858                            let excerpt_new_start =
2859                                ExcerptOffset::new(new_excerpts.summary().text.len.0);
2860                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
2861                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
2862                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
2863                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
2864                            Edit {
2865                                old: old_start..old_end,
2866                                new: new_start..new_end,
2867                            }
2868                        }),
2869                );
2870
2871                new_excerpt = Excerpt::new(
2872                    old_excerpt.id,
2873                    locator.clone(),
2874                    buffer_id,
2875                    buffer.snapshot(),
2876                    old_excerpt.range.clone(),
2877                    old_excerpt.has_trailing_newline,
2878                );
2879            } else {
2880                new_excerpt = old_excerpt.clone();
2881                new_excerpt.buffer = buffer.snapshot();
2882            }
2883
2884            new_excerpts.push(new_excerpt, ());
2885            cursor.next();
2886        }
2887        new_excerpts.append(cursor.suffix(), ());
2888
2889        drop(cursor);
2890        *excerpts = new_excerpts;
2891        Self::sync_diff_transforms(snapshot, edits, DiffChangeKind::BufferEdited)
2892    }
2893
2894    fn sync_diff_transforms(
2895        snapshot: &mut MultiBufferSnapshot,
2896        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
2897        change_kind: DiffChangeKind,
2898    ) -> Vec<Edit<MultiBufferOffset>> {
2899        if excerpt_edits.is_empty() {
2900            return vec![];
2901        }
2902
2903        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(());
2904        let mut old_diff_transforms = snapshot
2905            .diff_transforms
2906            .cursor::<Dimensions<ExcerptOffset, MultiBufferOffset>>(());
2907        let mut new_diff_transforms = SumTree::default();
2908        let mut old_expanded_hunks = HashSet::default();
2909        let mut output_edits = Vec::new();
2910        let mut output_delta = 0_isize;
2911        let mut at_transform_boundary = true;
2912        let mut end_of_current_insert = None;
2913
2914        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
2915        while let Some(edit) = excerpt_edits.next() {
2916            excerpts.seek_forward(&edit.new.start, Bias::Right);
2917            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
2918                excerpts.prev();
2919            }
2920
2921            // Keep any transforms that are before the edit.
2922            if at_transform_boundary {
2923                at_transform_boundary = false;
2924                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
2925                Self::append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
2926                if let Some(transform) = old_diff_transforms.item()
2927                    && old_diff_transforms.end().0 == edit.old.start
2928                    && old_diff_transforms.start().0 < edit.old.start
2929                {
2930                    Self::push_diff_transform(&mut new_diff_transforms, transform.clone());
2931                    old_diff_transforms.next();
2932                }
2933            }
2934
2935            // Compute the start of the edit in output coordinates.
2936            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
2937            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
2938            let edit_new_start =
2939                MultiBufferOffset((edit_old_start.0 as isize + output_delta) as usize);
2940
2941            let changed_diff_hunks = Self::recompute_diff_transforms_for_edit(
2942                &edit,
2943                &mut excerpts,
2944                &mut old_diff_transforms,
2945                &mut new_diff_transforms,
2946                &mut end_of_current_insert,
2947                &mut old_expanded_hunks,
2948                snapshot,
2949                change_kind,
2950            );
2951
2952            // Compute the end of the edit in output coordinates.
2953            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
2954            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
2955            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
2956            let edit_new_end =
2957                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
2958            let output_edit = Edit {
2959                old: edit_old_start..edit_old_end,
2960                new: edit_new_start..edit_new_end,
2961            };
2962
2963            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
2964            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
2965            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
2966                output_edits.push(output_edit);
2967            }
2968
2969            // If this is the last edit that intersects the current diff transform,
2970            // then recreate the content up to the end of this transform, to prepare
2971            // for reusing additional slices of the old transforms.
2972            if excerpt_edits
2973                .peek()
2974                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
2975            {
2976                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
2977                    && match old_diff_transforms.item() {
2978                        Some(DiffTransform::BufferContent {
2979                            inserted_hunk_info: Some(hunk),
2980                            ..
2981                        }) => excerpts.item().is_some_and(|excerpt| {
2982                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
2983                        }),
2984                        _ => true,
2985                    };
2986
2987                let mut excerpt_offset = edit.new.end;
2988                if !keep_next_old_transform {
2989                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
2990                    old_diff_transforms.next();
2991                }
2992
2993                old_expanded_hunks.clear();
2994                Self::push_buffer_content_transform(
2995                    snapshot,
2996                    &mut new_diff_transforms,
2997                    excerpt_offset,
2998                    end_of_current_insert,
2999                );
3000                at_transform_boundary = true;
3001            }
3002        }
3003
3004        // Keep any transforms that are after the last edit.
3005        Self::append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3006
3007        // Ensure there's always at least one buffer content transform.
3008        if new_diff_transforms.is_empty() {
3009            new_diff_transforms.push(
3010                DiffTransform::BufferContent {
3011                    summary: Default::default(),
3012                    inserted_hunk_info: None,
3013                },
3014                (),
3015            );
3016        }
3017
3018        drop(old_diff_transforms);
3019        drop(excerpts);
3020        snapshot.diff_transforms = new_diff_transforms;
3021        snapshot.edit_count += 1;
3022
3023        #[cfg(any(test, feature = "test-support"))]
3024        snapshot.check_invariants();
3025        output_edits
3026    }
3027
3028    fn recompute_diff_transforms_for_edit(
3029        edit: &Edit<TypedOffset<Excerpt>>,
3030        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3031        old_diff_transforms: &mut Cursor<
3032            DiffTransform,
3033            Dimensions<TypedOffset<Excerpt>, MultiBufferOffset>,
3034        >,
3035        new_diff_transforms: &mut SumTree<DiffTransform>,
3036        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3037        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3038        snapshot: &MultiBufferSnapshot,
3039        change_kind: DiffChangeKind,
3040    ) -> bool {
3041        log::trace!(
3042            "recomputing diff transform for edit {:?} => {:?}",
3043            edit.old.start.value..edit.old.end.value,
3044            edit.new.start.value..edit.new.end.value
3045        );
3046
3047        // Record which hunks were previously expanded.
3048        while let Some(item) = old_diff_transforms.item() {
3049            if let Some(hunk_info) = item.hunk_info() {
3050                log::trace!(
3051                    "previously expanded hunk at {}",
3052                    old_diff_transforms.start().0
3053                );
3054                old_expanded_hunks.insert(hunk_info);
3055            }
3056            if old_diff_transforms.end().0 > edit.old.end {
3057                break;
3058            }
3059            old_diff_transforms.next();
3060        }
3061
3062        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3063        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3064        if old_expanded_hunks.is_empty()
3065            && change_kind == DiffChangeKind::BufferEdited
3066            && !all_diff_hunks_expanded
3067        {
3068            return false;
3069        }
3070
3071        // Visit each excerpt that intersects the edit.
3072        let mut did_expand_hunks = false;
3073        while let Some(excerpt) = excerpts.item() {
3074            // Recompute the expanded hunks in the portion of the excerpt that
3075            // intersects the edit.
3076            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3077                let buffer = &excerpt.buffer;
3078                let excerpt_start = *excerpts.start();
3079                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3080                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3081                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3082                let edit_buffer_start =
3083                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3084                let edit_buffer_end =
3085                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3086                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3087                let edit_anchor_range =
3088                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3089
3090                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3091                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3092                        continue;
3093                    }
3094
3095                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3096                    if hunk_buffer_range.start < excerpt_buffer_start {
3097                        log::trace!("skipping hunk that starts before excerpt");
3098                        continue;
3099                    }
3100
3101                    let hunk_info = DiffTransformHunkInfo {
3102                        excerpt_id: excerpt.id,
3103                        hunk_start_anchor: hunk.buffer_range.start,
3104                        hunk_secondary_status: hunk.secondary_status,
3105                    };
3106
3107                    let hunk_excerpt_start = excerpt_start
3108                        + ExcerptOffset::new(
3109                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3110                        );
3111                    let hunk_excerpt_end = excerpt_end.min(
3112                        excerpt_start
3113                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3114                    );
3115
3116                    Self::push_buffer_content_transform(
3117                        snapshot,
3118                        new_diff_transforms,
3119                        hunk_excerpt_start,
3120                        *end_of_current_insert,
3121                    );
3122
3123                    // For every existing hunk, determine if it was previously expanded
3124                    // and if it should currently be expanded.
3125                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3126                    let should_expand_hunk = match &change_kind {
3127                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3128                            was_previously_expanded || all_diff_hunks_expanded
3129                        }
3130                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3131                            let intersects = hunk_buffer_range.is_empty()
3132                                || hunk_buffer_range.end > edit_buffer_start;
3133                            if *expand {
3134                                intersects || was_previously_expanded || all_diff_hunks_expanded
3135                            } else {
3136                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3137                            }
3138                        }
3139                        _ => was_previously_expanded || all_diff_hunks_expanded,
3140                    };
3141
3142                    if should_expand_hunk {
3143                        did_expand_hunks = true;
3144                        log::trace!(
3145                            "expanding hunk {:?}, excerpt:{:?}",
3146                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3147                            excerpt.id
3148                        );
3149
3150                        if !hunk.diff_base_byte_range.is_empty()
3151                            && hunk_buffer_range.start >= edit_buffer_start
3152                            && hunk_buffer_range.start <= excerpt_buffer_end
3153                        {
3154                            let base_text = diff.base_text();
3155                            let mut text_cursor =
3156                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3157                            let mut base_text_summary =
3158                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3159
3160                            let mut has_trailing_newline = false;
3161                            if base_text_summary.last_line_chars > 0 {
3162                                base_text_summary += TextSummary::newline();
3163                                has_trailing_newline = true;
3164                            }
3165
3166                            new_diff_transforms.push(
3167                                DiffTransform::DeletedHunk {
3168                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3169                                    summary: base_text_summary,
3170                                    buffer_id: excerpt.buffer_id,
3171                                    hunk_info,
3172                                    has_trailing_newline,
3173                                },
3174                                (),
3175                            );
3176                        }
3177
3178                        if !hunk_buffer_range.is_empty() {
3179                            *end_of_current_insert =
3180                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3181                        }
3182                    }
3183                }
3184            }
3185
3186            if excerpts.end() <= edit.new.end {
3187                excerpts.next();
3188            } else {
3189                break;
3190            }
3191        }
3192
3193        did_expand_hunks || !old_expanded_hunks.is_empty()
3194    }
3195
3196    fn append_diff_transforms(
3197        new_transforms: &mut SumTree<DiffTransform>,
3198        subtree: SumTree<DiffTransform>,
3199    ) {
3200        if let Some(DiffTransform::BufferContent {
3201            inserted_hunk_info,
3202            summary,
3203        }) = subtree.first()
3204            && Self::extend_last_buffer_content_transform(
3205                new_transforms,
3206                *inserted_hunk_info,
3207                *summary,
3208            )
3209        {
3210            let mut cursor = subtree.cursor::<()>(());
3211            cursor.next();
3212            cursor.next();
3213            new_transforms.append(cursor.suffix(), ());
3214            return;
3215        }
3216        new_transforms.append(subtree, ());
3217    }
3218
3219    fn push_diff_transform(new_transforms: &mut SumTree<DiffTransform>, transform: DiffTransform) {
3220        if let DiffTransform::BufferContent {
3221            inserted_hunk_info: inserted_hunk_anchor,
3222            summary,
3223        } = transform
3224            && Self::extend_last_buffer_content_transform(
3225                new_transforms,
3226                inserted_hunk_anchor,
3227                summary,
3228            )
3229        {
3230            return;
3231        }
3232        new_transforms.push(transform, ());
3233    }
3234
3235    fn push_buffer_content_transform(
3236        old_snapshot: &MultiBufferSnapshot,
3237        new_transforms: &mut SumTree<DiffTransform>,
3238        end_offset: ExcerptOffset,
3239        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3240    ) {
3241        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3242            (end_offset.min(insertion_end_offset), Some(hunk_info))
3243        });
3244        let unchanged_region = [(end_offset, None)];
3245
3246        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3247        {
3248            let start_offset = new_transforms.summary().excerpt_len();
3249            if end_offset <= start_offset {
3250                continue;
3251            }
3252            let summary_to_add = old_snapshot
3253                .text_summary_for_excerpt_offset_range::<MBTextSummary>(start_offset..end_offset);
3254
3255            if !Self::extend_last_buffer_content_transform(
3256                new_transforms,
3257                inserted_hunk_info,
3258                summary_to_add,
3259            ) {
3260                new_transforms.push(
3261                    DiffTransform::BufferContent {
3262                        summary: summary_to_add,
3263                        inserted_hunk_info,
3264                    },
3265                    (),
3266                )
3267            }
3268        }
3269    }
3270
3271    fn extend_last_buffer_content_transform(
3272        new_transforms: &mut SumTree<DiffTransform>,
3273        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3274        summary_to_add: MBTextSummary,
3275    ) -> bool {
3276        let mut did_extend = false;
3277        new_transforms.update_last(
3278            |last_transform| {
3279                if let DiffTransform::BufferContent {
3280                    summary,
3281                    inserted_hunk_info: inserted_hunk_anchor,
3282                } = last_transform
3283                    && *inserted_hunk_anchor == new_inserted_hunk_info
3284                {
3285                    *summary += summary_to_add;
3286                    did_extend = true;
3287                }
3288            },
3289            (),
3290        );
3291        did_extend
3292    }
3293}
3294
3295fn build_excerpt_ranges(
3296    ranges: impl IntoIterator<Item = Range<Point>>,
3297    context_line_count: u32,
3298    buffer_snapshot: &BufferSnapshot,
3299) -> Vec<ExcerptRange<Point>> {
3300    ranges
3301        .into_iter()
3302        .map(|range| {
3303            let start_row = range.start.row.saturating_sub(context_line_count);
3304            let start = Point::new(start_row, 0);
3305            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3306            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3307            ExcerptRange {
3308                context: start..end,
3309                primary: range,
3310            }
3311        })
3312        .collect()
3313}
3314
3315#[cfg(any(test, feature = "test-support"))]
3316impl MultiBuffer {
3317    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3318        let buffer = cx.new(|cx| Buffer::local(text, cx));
3319        cx.new(|cx| Self::singleton(buffer, cx))
3320    }
3321
3322    pub fn build_multi<const COUNT: usize>(
3323        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3324        cx: &mut gpui::App,
3325    ) -> Entity<Self> {
3326        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3327        for (text, ranges) in excerpts {
3328            let buffer = cx.new(|cx| Buffer::local(text, cx));
3329            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3330            multi.update(cx, |multi, cx| {
3331                multi.push_excerpts(buffer, excerpt_ranges, cx)
3332            });
3333        }
3334
3335        multi
3336    }
3337
3338    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3339        cx.new(|cx| Self::singleton(buffer, cx))
3340    }
3341
3342    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3343        cx.new(|cx| {
3344            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3345            let mutation_count = rng.random_range(1..=5);
3346            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3347            multibuffer
3348        })
3349    }
3350
3351    pub fn randomly_edit(
3352        &mut self,
3353        rng: &mut impl rand::Rng,
3354        edit_count: usize,
3355        cx: &mut Context<Self>,
3356    ) {
3357        use util::RandomCharIter;
3358
3359        let snapshot = self.read(cx);
3360        let mut edits: Vec<(Range<MultiBufferOffset>, Arc<str>)> = Vec::new();
3361        let mut last_end = None;
3362        for _ in 0..edit_count {
3363            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3364                break;
3365            }
3366
3367            let new_start = last_end.map_or(MultiBufferOffset::ZERO, |last_end| last_end + 1usize);
3368            let end =
3369                snapshot.clip_offset(rng.random_range(new_start..=snapshot.len()), Bias::Right);
3370            let start = snapshot.clip_offset(rng.random_range(new_start..=end), Bias::Right);
3371            last_end = Some(end);
3372
3373            let mut range = start..end;
3374            if rng.random_bool(0.2) {
3375                mem::swap(&mut range.start, &mut range.end);
3376            }
3377
3378            let new_text_len = rng.random_range(0..10);
3379            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3380
3381            edits.push((range, new_text.into()));
3382        }
3383        log::info!("mutating multi-buffer with {:?}", edits);
3384        drop(snapshot);
3385
3386        self.edit(edits, None, cx);
3387    }
3388
3389    pub fn randomly_edit_excerpts(
3390        &mut self,
3391        rng: &mut impl rand::Rng,
3392        mutation_count: usize,
3393        cx: &mut Context<Self>,
3394    ) {
3395        use rand::prelude::*;
3396        use std::env;
3397        use util::RandomCharIter;
3398
3399        let max_excerpts = env::var("MAX_EXCERPTS")
3400            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3401            .unwrap_or(5);
3402
3403        let mut buffers = Vec::new();
3404        for _ in 0..mutation_count {
3405            if rng.random_bool(0.05) {
3406                log::info!("Clearing multi-buffer");
3407                self.clear(cx);
3408                continue;
3409            } else if rng.random_bool(0.1) && !self.excerpt_ids().is_empty() {
3410                let ids = self.excerpt_ids();
3411                let mut excerpts = HashSet::default();
3412                for _ in 0..rng.random_range(0..ids.len()) {
3413                    excerpts.extend(ids.choose(rng).copied());
3414                }
3415
3416                let line_count = rng.random_range(0..5);
3417
3418                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3419
3420                self.expand_excerpts(
3421                    excerpts.iter().cloned(),
3422                    line_count,
3423                    ExpandExcerptDirection::UpAndDown,
3424                    cx,
3425                );
3426                continue;
3427            }
3428
3429            let excerpt_ids = self.excerpt_ids();
3430            if excerpt_ids.is_empty() || (rng.random() && excerpt_ids.len() < max_excerpts) {
3431                let buffer_handle = if rng.random() || self.buffers.is_empty() {
3432                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3433                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3434                    let buffer = buffers.last().unwrap().read(cx);
3435                    log::info!(
3436                        "Creating new buffer {} with text: {:?}",
3437                        buffer.remote_id(),
3438                        buffer.text()
3439                    );
3440                    buffers.last().unwrap().clone()
3441                } else {
3442                    self.buffers.values().choose(rng).unwrap().buffer.clone()
3443                };
3444
3445                let buffer = buffer_handle.read(cx);
3446                let buffer_text = buffer.text();
3447                let ranges = (0..rng.random_range(0..5))
3448                    .map(|_| {
3449                        let end_ix =
3450                            buffer.clip_offset(rng.random_range(0..=buffer.len()), Bias::Right);
3451                        let start_ix = buffer.clip_offset(rng.random_range(0..=end_ix), Bias::Left);
3452                        ExcerptRange::new(start_ix..end_ix)
3453                    })
3454                    .collect::<Vec<_>>();
3455                log::info!(
3456                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3457                    buffer_handle.read(cx).remote_id(),
3458                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3459                    ranges
3460                        .iter()
3461                        .map(|r| &buffer_text[r.context.clone()])
3462                        .collect::<Vec<_>>()
3463                );
3464
3465                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3466                log::info!("Inserted with ids: {:?}", excerpt_id);
3467            } else {
3468                let remove_count = rng.random_range(1..=excerpt_ids.len());
3469                let mut excerpts_to_remove = excerpt_ids
3470                    .choose_multiple(rng, remove_count)
3471                    .cloned()
3472                    .collect::<Vec<_>>();
3473                let snapshot = self.snapshot.borrow();
3474                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3475                drop(snapshot);
3476                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3477                self.remove_excerpts(excerpts_to_remove, cx);
3478            }
3479        }
3480    }
3481
3482    pub fn randomly_mutate(
3483        &mut self,
3484        rng: &mut impl rand::Rng,
3485        mutation_count: usize,
3486        cx: &mut Context<Self>,
3487    ) {
3488        use rand::prelude::*;
3489
3490        if rng.random_bool(0.7) || self.singleton {
3491            let buffer = self
3492                .buffers
3493                .values()
3494                .choose(rng)
3495                .map(|state| state.buffer.clone());
3496
3497            if let Some(buffer) = buffer {
3498                buffer.update(cx, |buffer, cx| {
3499                    if rng.random() {
3500                        buffer.randomly_edit(rng, mutation_count, cx);
3501                    } else {
3502                        buffer.randomly_undo_redo(rng, cx);
3503                    }
3504                });
3505            } else {
3506                self.randomly_edit(rng, mutation_count, cx);
3507            }
3508        } else {
3509            self.randomly_edit_excerpts(rng, mutation_count, cx);
3510        }
3511
3512        self.check_invariants(cx);
3513    }
3514
3515    fn check_invariants(&self, cx: &App) {
3516        self.read(cx).check_invariants();
3517    }
3518}
3519
3520impl EventEmitter<Event> for MultiBuffer {}
3521
3522impl MultiBufferSnapshot {
3523    pub fn text(&self) -> String {
3524        self.chunks(MultiBufferOffset::ZERO..self.len(), false)
3525            .map(|chunk| chunk.text)
3526            .collect()
3527    }
3528
3529    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3530        self.reversed_chunks_in_range(MultiBufferOffset::ZERO..position.to_offset(self))
3531            .flat_map(|c| c.chars().rev())
3532    }
3533
3534    fn reversed_chunks_in_range(
3535        &self,
3536        range: Range<MultiBufferOffset>,
3537    ) -> ReversedMultiBufferChunks<'_> {
3538        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3539        cursor.seek(&range.end);
3540        let current_chunks = cursor.region().as_ref().map(|region| {
3541            let start_overshoot = range.start.saturating_sub(region.range.start);
3542            let end_overshoot = range.end - region.range.start;
3543            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3544            let start = region.buffer_range.start + start_overshoot;
3545            region.buffer.reversed_chunks_in_range(start..end)
3546        });
3547        ReversedMultiBufferChunks {
3548            cursor,
3549            current_chunks,
3550            start: range.start,
3551            offset: range.end,
3552        }
3553    }
3554
3555    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3556        let offset = position.to_offset(self);
3557        self.text_for_range(offset..self.len())
3558            .flat_map(|chunk| chunk.chars())
3559    }
3560
3561    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3562        self.chunks(range, false).map(|chunk| chunk.text)
3563    }
3564
3565    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3566        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3567            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3568    }
3569
3570    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3571    where
3572        T: ToOffset,
3573    {
3574        let position = position.to_offset(self);
3575        position == self.clip_offset(position, Bias::Left)
3576            && self
3577                .bytes_in_range(position..self.len())
3578                .flatten()
3579                .copied()
3580                .take(needle.len())
3581                .eq(needle.bytes())
3582    }
3583
3584    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3585        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3586    }
3587
3588    pub fn diff_hunks_in_range<T: ToPoint>(
3589        &self,
3590        range: Range<T>,
3591    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3592        let query_range = range.start.to_point(self)..range.end.to_point(self);
3593        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3594            let diff = self.diffs.get(&buffer.remote_id())?;
3595            let buffer_start = buffer.anchor_before(buffer_range.start);
3596            let buffer_end = buffer.anchor_after(buffer_range.end);
3597            Some(
3598                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3599                    .filter_map(|hunk| {
3600                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3601                            return None;
3602                        }
3603                        Some((hunk.range.clone(), hunk))
3604                    }),
3605            )
3606        })
3607        .filter_map(move |(range, hunk, excerpt)| {
3608            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3609            {
3610                return None;
3611            }
3612            let end_row = if range.end.column == 0 {
3613                range.end.row
3614            } else {
3615                range.end.row + 1
3616            };
3617            Some(MultiBufferDiffHunk {
3618                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3619                buffer_id: excerpt.buffer_id,
3620                excerpt_id: excerpt.id,
3621                buffer_range: hunk.buffer_range.clone(),
3622                diff_base_byte_range: BufferOffset(hunk.diff_base_byte_range.start)
3623                    ..BufferOffset(hunk.diff_base_byte_range.end),
3624                secondary_status: hunk.secondary_status,
3625            })
3626        })
3627    }
3628
3629    pub fn excerpt_ids_for_range<T: ToOffset>(
3630        &self,
3631        range: Range<T>,
3632    ) -> impl Iterator<Item = ExcerptId> + '_ {
3633        let range = range.start.to_offset(self)..range.end.to_offset(self);
3634        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3635        cursor.seek(&range.start);
3636        std::iter::from_fn(move || {
3637            let region = cursor.region()?;
3638            if region.range.start >= range.end {
3639                return None;
3640            }
3641            cursor.next_excerpt();
3642            Some(region.excerpt.id)
3643        })
3644    }
3645
3646    pub fn buffer_ids_for_range<T: ToOffset>(
3647        &self,
3648        range: Range<T>,
3649    ) -> impl Iterator<Item = BufferId> + '_ {
3650        let range = range.start.to_offset(self)..range.end.to_offset(self);
3651        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3652        cursor.seek(&range.start);
3653        std::iter::from_fn(move || {
3654            let region = cursor.region()?;
3655            if region.range.start > range.end
3656                || region.range.start == range.end && region.range.start > range.start
3657            {
3658                return None;
3659            }
3660            cursor.next_excerpt();
3661            Some(region.excerpt.buffer_id)
3662        })
3663    }
3664
3665    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3666        &self,
3667        ranges: impl Iterator<Item = Range<T>>,
3668    ) -> impl Iterator<Item = (&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3669        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3670    }
3671
3672    pub fn range_to_buffer_ranges<T: ToOffset>(
3673        &self,
3674        range: Range<T>,
3675    ) -> Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> {
3676        let start = range.start.to_offset(self);
3677        let end = range.end.to_offset(self);
3678
3679        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3680        cursor.seek(&start);
3681
3682        let mut result: Vec<(&BufferSnapshot, Range<BufferOffset>, ExcerptId)> = Vec::new();
3683        while let Some(region) = cursor.region() {
3684            if region.range.start > end {
3685                break;
3686            }
3687            if region.is_main_buffer {
3688                let start_overshoot = start.saturating_sub(region.range.start);
3689                let end_overshoot = end.saturating_sub(region.range.start);
3690                let start = region
3691                    .buffer_range
3692                    .end
3693                    .min(region.buffer_range.start + start_overshoot);
3694                let end = region
3695                    .buffer_range
3696                    .end
3697                    .min(region.buffer_range.start + end_overshoot);
3698                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3699                    *excerpt_id == region.excerpt.id && prev_range.end == start
3700                }) {
3701                    prev.1.end = end;
3702                } else {
3703                    result.push((region.buffer, start..end, region.excerpt.id));
3704                }
3705            }
3706            cursor.next();
3707        }
3708        result
3709    }
3710
3711    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3712        &self,
3713        range: Range<T>,
3714    ) -> impl Iterator<
3715        Item = (
3716            &BufferSnapshot,
3717            Range<BufferOffset>,
3718            ExcerptId,
3719            Option<Anchor>,
3720        ),
3721    > + '_ {
3722        let start = range.start.to_offset(self);
3723        let end = range.end.to_offset(self);
3724
3725        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
3726        cursor.seek(&start);
3727
3728        std::iter::from_fn(move || {
3729            let region = cursor.region()?;
3730            if region.range.start > end {
3731                return None;
3732            }
3733            let start_overshoot = start.saturating_sub(region.range.start);
3734            let end_overshoot = end.saturating_sub(region.range.start);
3735            let start = region
3736                .buffer_range
3737                .end
3738                .min(region.buffer_range.start + start_overshoot);
3739            let end = region
3740                .buffer_range
3741                .end
3742                .min(region.buffer_range.start + end_overshoot);
3743
3744            let region_excerpt_id = region.excerpt.id;
3745            let deleted_hunk_anchor = if region.is_main_buffer {
3746                None
3747            } else {
3748                Some(self.anchor_before(region.range.start))
3749            };
3750            let result = (
3751                region.buffer,
3752                start..end,
3753                region_excerpt_id,
3754                deleted_hunk_anchor,
3755            );
3756            cursor.next();
3757            Some(result)
3758        })
3759    }
3760
3761    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3762    /// coordinates.
3763    ///
3764    /// The given callback will be called for every excerpt intersecting the given range. It will
3765    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3766    /// The callback should return an iterator of metadata items from that buffer, each paired
3767    /// with a buffer range.
3768    ///
3769    /// The returned iterator yields each of these metadata items, paired with its range in
3770    /// multi-buffer coordinates.
3771    fn lift_buffer_metadata<'a, MBD, M, I>(
3772        &'a self,
3773        query_range: Range<MBD>,
3774        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<MBD::TextDimension>) -> Option<I>,
3775    ) -> impl Iterator<Item = (Range<MBD>, M, &'a Excerpt)> + 'a
3776    where
3777        I: Iterator<Item = (Range<MBD::TextDimension>, M)> + 'a,
3778        MBD: MultiBufferDimension
3779            + Ord
3780            + Sub<Output = MBD::TextDimension>
3781            + ops::Add<MBD::TextDimension, Output = MBD>
3782            + ops::AddAssign<MBD::TextDimension>,
3783        MBD::TextDimension: Sub<Output = MBD::TextDimension>
3784            + ops::Add<Output = MBD::TextDimension>
3785            + AddAssign<MBD::TextDimension>
3786            + Ord,
3787    {
3788        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3789        let mut cursor = self.cursor::<MBD, MBD::TextDimension>();
3790
3791        // Find the excerpt and buffer offset where the given range ends.
3792        cursor.seek(&query_range.end);
3793        let mut range_end = None;
3794        while let Some(region) = cursor.region() {
3795            if region.is_main_buffer {
3796                let mut buffer_end = region.buffer_range.start;
3797                let overshoot = if query_range.end > region.range.start {
3798                    query_range.end - region.range.start
3799                } else {
3800                    <MBD::TextDimension>::default()
3801                };
3802                buffer_end = buffer_end + overshoot;
3803                range_end = Some((region.excerpt.id, buffer_end));
3804                break;
3805            }
3806            cursor.next();
3807        }
3808
3809        cursor.seek(&query_range.start);
3810
3811        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
3812            && region.range.start > MBD::default()
3813        {
3814            cursor.prev()
3815        }
3816
3817        iter::from_fn(move || {
3818            loop {
3819                let excerpt = cursor.excerpt()?;
3820
3821                // If we have already retrieved metadata for this excerpt, continue to use it.
3822                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3823                    .as_mut()
3824                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3825                {
3826                    Some(metadata)
3827                }
3828                // Otherwise, compute the intersection of the input range with the excerpt's range,
3829                // and retrieve the metadata for the resulting range.
3830                else {
3831                    let region = cursor.region()?;
3832                    let mut buffer_start;
3833                    if region.is_main_buffer {
3834                        buffer_start = region.buffer_range.start;
3835                        if query_range.start > region.range.start {
3836                            let overshoot = query_range.start - region.range.start;
3837                            buffer_start = buffer_start + overshoot;
3838                        }
3839                        buffer_start = buffer_start.min(region.buffer_range.end);
3840                    } else {
3841                        buffer_start = cursor.main_buffer_position()?;
3842                    };
3843                    let mut buffer_end = excerpt
3844                        .range
3845                        .context
3846                        .end
3847                        .summary::<MBD::TextDimension>(&excerpt.buffer);
3848                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
3849                        && excerpt.id == end_excerpt_id
3850                    {
3851                        buffer_end = buffer_end.min(end_buffer_offset);
3852                    }
3853
3854                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
3855                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
3856                    })
3857                };
3858
3859                // Visit each metadata item.
3860                if let Some((metadata_buffer_range, metadata)) =
3861                    metadata_iter.and_then(Iterator::next)
3862                {
3863                    // Find the multibuffer regions that contain the start and end of
3864                    // the metadata item's range.
3865                    if metadata_buffer_range.start > <MBD::TextDimension>::default() {
3866                        while let Some(region) = cursor.region() {
3867                            if region.is_main_buffer
3868                                && (region.buffer_range.end >= metadata_buffer_range.start
3869                                    || cursor.is_at_end_of_excerpt())
3870                            {
3871                                break;
3872                            }
3873                            cursor.next();
3874                        }
3875                    }
3876                    let start_region = cursor.region()?;
3877                    while let Some(region) = cursor.region() {
3878                        if region.is_main_buffer
3879                            && (region.buffer_range.end > metadata_buffer_range.end
3880                                || cursor.is_at_end_of_excerpt())
3881                        {
3882                            break;
3883                        }
3884                        cursor.next();
3885                    }
3886                    let end_region = cursor.region();
3887
3888                    // Convert the metadata item's range into multibuffer coordinates.
3889                    let mut start_position = start_region.range.start;
3890                    let region_buffer_start = start_region.buffer_range.start;
3891                    if start_region.is_main_buffer
3892                        && metadata_buffer_range.start > region_buffer_start
3893                    {
3894                        start_position =
3895                            start_position + (metadata_buffer_range.start - region_buffer_start);
3896                        start_position = start_position.min(start_region.range.end);
3897                    }
3898
3899                    let mut end_position = self.max_position();
3900                    if let Some(end_region) = &end_region {
3901                        end_position = end_region.range.start;
3902                        debug_assert!(end_region.is_main_buffer);
3903                        let region_buffer_start = end_region.buffer_range.start;
3904                        if metadata_buffer_range.end > region_buffer_start {
3905                            end_position =
3906                                end_position + (metadata_buffer_range.end - region_buffer_start);
3907                        }
3908                        end_position = end_position.min(end_region.range.end);
3909                    }
3910
3911                    if start_position <= query_range.end && end_position >= query_range.start {
3912                        return Some((start_position..end_position, metadata, excerpt));
3913                    }
3914                }
3915                // When there are no more metadata items for this excerpt, move to the next excerpt.
3916                else {
3917                    current_excerpt_metadata.take();
3918                    if let Some((end_excerpt_id, _)) = range_end
3919                        && excerpt.id == end_excerpt_id
3920                    {
3921                        return None;
3922                    }
3923                    cursor.next_excerpt();
3924                }
3925            }
3926        })
3927    }
3928
3929    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
3930        let offset = position.to_offset(self);
3931
3932        let mut cursor = self
3933            .cursor::<DimensionPair<MultiBufferOffset, Point>, DimensionPair<BufferOffset, Point>>(
3934            );
3935        cursor.seek(&DimensionPair {
3936            key: offset,
3937            value: None,
3938        });
3939        cursor.seek_to_start_of_current_excerpt();
3940        let excerpt = cursor.excerpt()?;
3941
3942        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
3943        let current_position = self
3944            .anchor_before(offset)
3945            .text_anchor
3946            .to_offset(&excerpt.buffer);
3947        let excerpt_end = excerpt
3948            .buffer
3949            .anchor_before(excerpt_end.min(current_position));
3950
3951        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
3952            for hunk in diff.hunks_intersecting_range_rev(
3953                excerpt.range.context.start..excerpt_end,
3954                &excerpt.buffer,
3955            ) {
3956                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
3957                if hunk_end >= current_position {
3958                    continue;
3959                }
3960                let start =
3961                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3962                        .to_point(self);
3963                return Some(MultiBufferRow(start.row));
3964            }
3965        }
3966
3967        loop {
3968            cursor.prev_excerpt();
3969            let excerpt = cursor.excerpt()?;
3970
3971            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
3972                continue;
3973            };
3974            let mut hunks =
3975                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
3976            let Some(hunk) = hunks.next() else {
3977                continue;
3978            };
3979            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
3980                .to_point(self);
3981            return Some(MultiBufferRow(start.row));
3982        }
3983    }
3984
3985    pub fn has_diff_hunks(&self) -> bool {
3986        self.diffs.values().any(|diff| !diff.is_empty())
3987    }
3988
3989    pub fn is_inside_word<T: ToOffset>(
3990        &self,
3991        position: T,
3992        scope_context: Option<CharScopeContext>,
3993    ) -> bool {
3994        let position = position.to_offset(self);
3995        let classifier = self
3996            .char_classifier_at(position)
3997            .scope_context(scope_context);
3998        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
3999        let prev_char_kind = self
4000            .reversed_chars_at(position)
4001            .next()
4002            .map(|c| classifier.kind(c));
4003        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4004    }
4005
4006    pub fn surrounding_word<T: ToOffset>(
4007        &self,
4008        start: T,
4009        scope_context: Option<CharScopeContext>,
4010    ) -> (Range<MultiBufferOffset>, Option<CharKind>) {
4011        let mut start = start.to_offset(self);
4012        let mut end = start;
4013        let mut next_chars = self.chars_at(start).peekable();
4014        let mut prev_chars = self.reversed_chars_at(start).peekable();
4015
4016        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4017
4018        let word_kind = cmp::max(
4019            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4020            next_chars.peek().copied().map(|c| classifier.kind(c)),
4021        );
4022
4023        for ch in prev_chars {
4024            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4025                start -= ch.len_utf8();
4026            } else {
4027                break;
4028            }
4029        }
4030
4031        for ch in next_chars {
4032            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4033                end += ch.len_utf8();
4034            } else {
4035                break;
4036            }
4037        }
4038
4039        (start..end, word_kind)
4040    }
4041
4042    pub fn char_kind_before<T: ToOffset>(
4043        &self,
4044        start: T,
4045        scope_context: Option<CharScopeContext>,
4046    ) -> Option<CharKind> {
4047        let start = start.to_offset(self);
4048        let classifier = self.char_classifier_at(start).scope_context(scope_context);
4049        self.reversed_chars_at(start)
4050            .next()
4051            .map(|ch| classifier.kind(ch))
4052    }
4053
4054    pub fn is_singleton(&self) -> bool {
4055        self.singleton
4056    }
4057
4058    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4059        if self.singleton {
4060            self.excerpts
4061                .iter()
4062                .next()
4063                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4064        } else {
4065            None
4066        }
4067    }
4068
4069    pub fn len(&self) -> MultiBufferOffset {
4070        self.diff_transforms.summary().output.len
4071    }
4072
4073    pub fn max_position<MBD: MultiBufferDimension>(&self) -> MBD {
4074        MBD::from_summary(&self.text_summary())
4075    }
4076
4077    pub fn is_empty(&self) -> bool {
4078        self.diff_transforms.summary().output.len == MultiBufferOffset(0)
4079    }
4080
4081    pub fn widest_line_number(&self) -> u32 {
4082        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4083        self.excerpts.summary().widest_line_number + 1
4084    }
4085
4086    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4087        let range = range.start.to_offset(self)..range.end.to_offset(self);
4088        let mut excerpts = self.cursor::<MultiBufferOffset, BufferOffset>();
4089        excerpts.seek(&range.start);
4090
4091        let mut chunk;
4092        let mut has_trailing_newline;
4093        let excerpt_bytes;
4094        if let Some(region) = excerpts.region() {
4095            let mut bytes = region.buffer.bytes_in_range(
4096                region.buffer_range.start + (range.start - region.range.start)
4097                    ..(region.buffer_range.start + (range.end - region.range.start))
4098                        .min(region.buffer_range.end),
4099            );
4100            chunk = bytes.next().unwrap_or(&[][..]);
4101            excerpt_bytes = Some(bytes);
4102            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4103            if chunk.is_empty() && has_trailing_newline {
4104                chunk = b"\n";
4105                has_trailing_newline = false;
4106            }
4107        } else {
4108            chunk = &[][..];
4109            excerpt_bytes = None;
4110            has_trailing_newline = false;
4111        };
4112
4113        MultiBufferBytes {
4114            range,
4115            cursor: excerpts,
4116            excerpt_bytes,
4117            has_trailing_newline,
4118            chunk,
4119        }
4120    }
4121
4122    pub fn reversed_bytes_in_range<T: ToOffset>(
4123        &self,
4124        range: Range<T>,
4125    ) -> ReversedMultiBufferBytes<'_> {
4126        let range = range.start.to_offset(self)..range.end.to_offset(self);
4127        let mut chunks = self.reversed_chunks_in_range(range.clone());
4128        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4129        ReversedMultiBufferBytes {
4130            range,
4131            chunks,
4132            chunk,
4133        }
4134    }
4135
4136    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4137        let mut cursor = self.cursor::<Point, Point>();
4138        cursor.seek(&Point::new(start_row.0, 0));
4139        let mut result = MultiBufferRows {
4140            point: Point::new(0, 0),
4141            is_empty: self.excerpts.is_empty(),
4142            is_singleton: self.is_singleton(),
4143            cursor,
4144        };
4145        result.seek(start_row);
4146        result
4147    }
4148
4149    pub fn chunks<T: ToOffset>(
4150        &self,
4151        range: Range<T>,
4152        language_aware: bool,
4153    ) -> MultiBufferChunks<'_> {
4154        let mut chunks = MultiBufferChunks {
4155            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4156            range: MultiBufferOffset::ZERO..MultiBufferOffset::ZERO,
4157            excerpts: self.excerpts.cursor(()),
4158            diff_transforms: self.diff_transforms.cursor(()),
4159            diffs: &self.diffs,
4160            diff_base_chunks: None,
4161            excerpt_chunks: None,
4162            buffer_chunk: None,
4163            language_aware,
4164        };
4165        let range = range.start.to_offset(self)..range.end.to_offset(self);
4166        chunks.seek(range);
4167        chunks
4168    }
4169
4170    pub fn clip_offset(&self, offset: MultiBufferOffset, bias: Bias) -> MultiBufferOffset {
4171        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4172    }
4173
4174    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4175        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4176    }
4177
4178    pub fn clip_offset_utf16(
4179        &self,
4180        offset: MultiBufferOffsetUtf16,
4181        bias: Bias,
4182    ) -> MultiBufferOffsetUtf16 {
4183        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4184    }
4185
4186    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4187        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4188            buffer.clip_point_utf16(Unclipped(point), bias)
4189        })
4190    }
4191
4192    pub fn offset_to_point(&self, offset: MultiBufferOffset) -> Point {
4193        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4194    }
4195
4196    pub fn offset_to_point_utf16(&self, offset: MultiBufferOffset) -> PointUtf16 {
4197        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4198    }
4199
4200    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4201        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4202    }
4203
4204    pub fn point_utf16_to_point(&self, point: PointUtf16) -> Point {
4205        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_point)
4206    }
4207
4208    pub fn point_to_offset(&self, point: Point) -> MultiBufferOffset {
4209        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4210    }
4211
4212    pub fn point_to_offset_utf16(&self, point: Point) -> MultiBufferOffsetUtf16 {
4213        self.convert_dimension(point, text::BufferSnapshot::point_to_offset_utf16)
4214    }
4215
4216    pub fn offset_utf16_to_offset(&self, offset: MultiBufferOffsetUtf16) -> MultiBufferOffset {
4217        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4218    }
4219
4220    pub fn offset_to_offset_utf16(&self, offset: MultiBufferOffset) -> MultiBufferOffsetUtf16 {
4221        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4222    }
4223
4224    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> MultiBufferOffset {
4225        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4226    }
4227
4228    pub fn point_utf16_to_offset_utf16(&self, point: PointUtf16) -> MultiBufferOffsetUtf16 {
4229        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset_utf16)
4230    }
4231
4232    fn clip_dimension<MBD, BD>(
4233        &self,
4234        position: MBD,
4235        bias: Bias,
4236        clip_buffer_position: fn(&text::BufferSnapshot, BD, Bias) -> BD,
4237    ) -> MBD
4238    where
4239        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
4240        BD: TextDimension + Sub<Output = <MBD as Sub>::Output> + AddAssign<<MBD as Sub>::Output>,
4241    {
4242        let mut cursor = self.cursor::<MBD, BD>();
4243        cursor.seek(&position);
4244        if let Some(region) = cursor.region() {
4245            if position >= region.range.end {
4246                return region.range.end;
4247            }
4248            let overshoot = position - region.range.start;
4249            let mut buffer_position = region.buffer_range.start;
4250            buffer_position += overshoot;
4251            let clipped_buffer_position =
4252                clip_buffer_position(region.buffer, buffer_position, bias);
4253            let mut position = region.range.start;
4254            position += clipped_buffer_position - region.buffer_range.start;
4255            position
4256        } else {
4257            self.max_position()
4258        }
4259    }
4260
4261    fn convert_dimension<MBR1, MBR2, BR1, BR2>(
4262        &self,
4263        key: MBR1,
4264        convert_buffer_dimension: fn(&text::BufferSnapshot, BR1) -> BR2,
4265    ) -> MBR2
4266    where
4267        MBR1: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR1 as Sub>::Output>,
4268        BR1: TextDimension + Sub<Output = <MBR1 as Sub>::Output> + AddAssign<<MBR1 as Sub>::Output>,
4269        MBR2: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBR2 as Sub>::Output>,
4270        BR2: TextDimension + Sub<Output = <MBR2 as Sub>::Output> + AddAssign<<MBR2 as Sub>::Output>,
4271    {
4272        let mut cursor = self.cursor::<DimensionPair<MBR1, MBR2>, DimensionPair<BR1, BR2>>();
4273        cursor.seek(&DimensionPair { key, value: None });
4274        if let Some(region) = cursor.region() {
4275            if key >= region.range.end.key {
4276                return region.range.end.value.unwrap();
4277            }
4278            let start_key = region.range.start.key;
4279            let start_value = region.range.start.value.unwrap();
4280            let buffer_start_key = region.buffer_range.start.key;
4281            let buffer_start_value = region.buffer_range.start.value.unwrap();
4282            let mut buffer_key = buffer_start_key;
4283            buffer_key += key - start_key;
4284            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4285            let mut result = start_value;
4286            result += buffer_value - buffer_start_value;
4287            result
4288        } else {
4289            self.max_position()
4290        }
4291    }
4292
4293    pub fn point_to_buffer_offset<T: ToOffset>(
4294        &self,
4295        point: T,
4296    ) -> Option<(&BufferSnapshot, BufferOffset)> {
4297        let offset = point.to_offset(self);
4298        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
4299        cursor.seek(&offset);
4300        let region = cursor.region()?;
4301        let overshoot = offset - region.range.start;
4302        let buffer_offset = region.buffer_range.start + overshoot;
4303        if buffer_offset == BufferOffset(region.buffer.len() + 1)
4304            && region.has_trailing_newline
4305            && !region.is_main_buffer
4306        {
4307            let main_buffer_position = cursor.main_buffer_position()?;
4308            let buffer_snapshot = &cursor.excerpt()?.buffer;
4309            return Some((buffer_snapshot, main_buffer_position));
4310        } else if buffer_offset > BufferOffset(region.buffer.len()) {
4311            return None;
4312        }
4313        Some((region.buffer, buffer_offset))
4314    }
4315
4316    pub fn point_to_buffer_point(
4317        &self,
4318        point: Point,
4319    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4320        let mut cursor = self.cursor::<Point, Point>();
4321        cursor.seek(&point);
4322        let region = cursor.region()?;
4323        let overshoot = point - region.range.start;
4324        let buffer_point = region.buffer_range.start + overshoot;
4325        let excerpt = cursor.excerpt()?;
4326        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4327            && region.has_trailing_newline
4328            && !region.is_main_buffer
4329        {
4330            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4331        } else if buffer_point > region.buffer.max_point() {
4332            return None;
4333        }
4334        Some((region.buffer, buffer_point, excerpt.id))
4335    }
4336
4337    pub fn suggested_indents(
4338        &self,
4339        rows: impl IntoIterator<Item = u32>,
4340        cx: &App,
4341    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4342        let mut result = BTreeMap::new();
4343
4344        let mut rows_for_excerpt = Vec::new();
4345        let mut cursor = self.cursor::<Point, Point>();
4346        let mut rows = rows.into_iter().peekable();
4347        let mut prev_row = u32::MAX;
4348        let mut prev_language_indent_size = IndentSize::default();
4349
4350        while let Some(row) = rows.next() {
4351            cursor.seek(&Point::new(row, 0));
4352            let Some(region) = cursor.region() else {
4353                continue;
4354            };
4355
4356            // Retrieve the language and indent size once for each disjoint region being indented.
4357            let single_indent_size = if row.saturating_sub(1) == prev_row {
4358                prev_language_indent_size
4359            } else {
4360                region
4361                    .buffer
4362                    .language_indent_size_at(Point::new(row, 0), cx)
4363            };
4364            prev_language_indent_size = single_indent_size;
4365            prev_row = row;
4366
4367            let start_buffer_row = region.buffer_range.start.row;
4368            let start_multibuffer_row = region.range.start.row;
4369            let end_multibuffer_row = region.range.end.row;
4370
4371            rows_for_excerpt.push(row);
4372            while let Some(next_row) = rows.peek().copied() {
4373                if end_multibuffer_row > next_row {
4374                    rows_for_excerpt.push(next_row);
4375                    rows.next();
4376                } else {
4377                    break;
4378                }
4379            }
4380
4381            let buffer_rows = rows_for_excerpt
4382                .drain(..)
4383                .map(|row| start_buffer_row + row - start_multibuffer_row);
4384            let buffer_indents = region
4385                .buffer
4386                .suggested_indents(buffer_rows, single_indent_size);
4387            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4388                (
4389                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4390                    indent,
4391                )
4392            });
4393            result.extend(multibuffer_indents);
4394        }
4395
4396        result
4397    }
4398
4399    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4400        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4401            let mut size = buffer.indent_size_for_line(range.start.row);
4402            size.len = size
4403                .len
4404                .min(range.end.column)
4405                .saturating_sub(range.start.column);
4406            size
4407        } else {
4408            IndentSize::spaces(0)
4409        }
4410    }
4411
4412    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4413        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4414            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4415        } else {
4416            LineIndent::spaces(0)
4417        }
4418    }
4419
4420    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4421        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4422
4423        if self.language_settings(cx).extend_comment_on_newline
4424            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4425        {
4426            let delimiters = language_scope.line_comment_prefixes();
4427            for delimiter in delimiters {
4428                if *self
4429                    .chars_at(Point::new(row.0, indent.len() as u32))
4430                    .take(delimiter.chars().count())
4431                    .collect::<String>()
4432                    .as_str()
4433                    == **delimiter
4434                {
4435                    indent.push_str(delimiter);
4436                    break;
4437                }
4438            }
4439        }
4440
4441        indent
4442    }
4443
4444    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4445    where
4446        T: ToOffset,
4447    {
4448        for char in self.reversed_chars_at(position) {
4449            if !char.is_whitespace() {
4450                return false;
4451            }
4452            if char == '\n' {
4453                return true;
4454            }
4455        }
4456        true
4457    }
4458
4459    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4460        while row.0 > 0 {
4461            row.0 -= 1;
4462            if !self.is_line_blank(row) {
4463                return Some(row);
4464            }
4465        }
4466        None
4467    }
4468
4469    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4470        if let Some((_, range)) = self.buffer_line_for_row(row) {
4471            range.end.column - range.start.column
4472        } else {
4473            0
4474        }
4475    }
4476
4477    pub fn buffer_line_for_row(
4478        &self,
4479        row: MultiBufferRow,
4480    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4481        let mut cursor = self.cursor::<Point, Point>();
4482        let point = Point::new(row.0, 0);
4483        cursor.seek(&point);
4484        let region = cursor.region()?;
4485        let overshoot = point.min(region.range.end) - region.range.start;
4486        let buffer_point = region.buffer_range.start + overshoot;
4487        if buffer_point.row > region.buffer_range.end.row {
4488            return None;
4489        }
4490        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4491        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4492            .min(region.buffer_range.end);
4493        Some((region.buffer, line_start..line_end))
4494    }
4495
4496    pub fn max_point(&self) -> Point {
4497        self.text_summary().lines
4498    }
4499
4500    pub fn max_row(&self) -> MultiBufferRow {
4501        MultiBufferRow(self.text_summary().lines.row)
4502    }
4503
4504    pub fn text_summary(&self) -> MBTextSummary {
4505        self.diff_transforms.summary().output
4506    }
4507
4508    pub fn text_summary_for_range<MBD, O>(&self, range: Range<O>) -> MBD
4509    where
4510        MBD: MultiBufferDimension + AddAssign,
4511        O: ToOffset,
4512    {
4513        let range = range.start.to_offset(self)..range.end.to_offset(self);
4514        let mut cursor = self
4515            .diff_transforms
4516            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
4517        cursor.seek(&range.start, Bias::Right);
4518
4519        let Some(first_transform) = cursor.item() else {
4520            return MBD::from_summary(&MBTextSummary::default());
4521        };
4522
4523        let diff_transform_start = cursor.start().0;
4524        let diff_transform_end = cursor.end().0;
4525        let diff_start = range.start;
4526        let start_overshoot = diff_start - diff_transform_start;
4527        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4528
4529        let mut result = match first_transform {
4530            DiffTransform::BufferContent { .. } => {
4531                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4532                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4533                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4534            }
4535            DiffTransform::DeletedHunk {
4536                buffer_id,
4537                base_text_byte_range,
4538                has_trailing_newline,
4539                ..
4540            } => {
4541                let buffer_start = base_text_byte_range.start + start_overshoot;
4542                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4543                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4544                    panic!("{:?} is in non-existent deleted hunk", range.start)
4545                };
4546
4547                let include_trailing_newline =
4548                    *has_trailing_newline && range.end >= diff_transform_end;
4549                if include_trailing_newline {
4550                    buffer_end -= 1;
4551                }
4552
4553                let mut summary = base_text
4554                    .text_summary_for_range::<MBD::TextDimension, _>(buffer_start..buffer_end);
4555
4556                if include_trailing_newline {
4557                    summary.add_assign(&<MBD::TextDimension>::from_text_summary(
4558                        &TextSummary::newline(),
4559                    ))
4560                }
4561
4562                let mut result = MBD::default();
4563                result.add_text_dim(&summary);
4564                result
4565            }
4566        };
4567        if range.end < diff_transform_end {
4568            return result;
4569        }
4570
4571        cursor.next();
4572        result.add_mb_text_summary(
4573            &cursor
4574                .summary::<_, OutputDimension<_>>(&range.end, Bias::Right)
4575                .0,
4576        );
4577
4578        let Some(last_transform) = cursor.item() else {
4579            return result;
4580        };
4581
4582        let overshoot = range.end - cursor.start().0;
4583        let suffix = match last_transform {
4584            DiffTransform::BufferContent { .. } => {
4585                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4586                self.text_summary_for_excerpt_offset_range::<MBD>(cursor.start().1..end)
4587            }
4588            DiffTransform::DeletedHunk {
4589                base_text_byte_range,
4590                buffer_id,
4591                has_trailing_newline,
4592                ..
4593            } => {
4594                let buffer_end = base_text_byte_range.start + overshoot;
4595                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4596                    panic!("{:?} is in non-existent deleted hunk", range.end)
4597                };
4598
4599                let mut suffix = base_text.text_summary_for_range::<MBD::TextDimension, _>(
4600                    base_text_byte_range.start..buffer_end,
4601                );
4602                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4603                    suffix.add_assign(&<MBD::TextDimension>::from_text_summary(
4604                        &TextSummary::from("\n"),
4605                    ))
4606                }
4607
4608                let mut result = MBD::default();
4609                result.add_text_dim(&suffix);
4610                result
4611            }
4612        };
4613
4614        result += suffix;
4615        result
4616    }
4617
4618    fn text_summary_for_excerpt_offset_range<MBD>(&self, mut range: Range<ExcerptOffset>) -> MBD
4619    where
4620        MBD: MultiBufferDimension + AddAssign,
4621    {
4622        let mut summary = MBD::default();
4623        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(());
4624        cursor.seek(&range.start, Bias::Right);
4625        if let Some(excerpt) = cursor.item() {
4626            let mut end_before_newline = cursor.end();
4627            if excerpt.has_trailing_newline {
4628                end_before_newline -= ExcerptOffset::new(1);
4629            }
4630
4631            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4632            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4633            let end_in_excerpt =
4634                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4635            summary.add_text_dim(
4636                &excerpt
4637                    .buffer
4638                    .text_summary_for_range::<MBD::TextDimension, _>(
4639                        start_in_excerpt..end_in_excerpt,
4640                    ),
4641            );
4642
4643            if range.end > end_before_newline {
4644                summary.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4645            }
4646
4647            cursor.next();
4648        }
4649
4650        if range.end > *cursor.start() {
4651            summary += cursor
4652                .summary::<_, ExcerptDimension<MBD>>(&range.end, Bias::Right)
4653                .0;
4654            if let Some(excerpt) = cursor.item() {
4655                range.end = cmp::max(*cursor.start(), range.end);
4656
4657                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4658                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4659                summary.add_text_dim(
4660                    &excerpt
4661                        .buffer
4662                        .text_summary_for_range::<MBD::TextDimension, _>(
4663                            excerpt_start..end_in_excerpt,
4664                        ),
4665                );
4666            }
4667        }
4668
4669        summary
4670    }
4671
4672    pub fn summary_for_anchor<MBD>(&self, anchor: &Anchor) -> MBD
4673    where
4674        MBD: MultiBufferDimension
4675            + Ord
4676            + Sub<Output = MBD::TextDimension>
4677            + AddAssign<MBD::TextDimension>,
4678        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4679    {
4680        self.summaries_for_anchors([anchor])[0]
4681    }
4682
4683    fn resolve_summary_for_anchor<MBD>(
4684        &self,
4685        anchor: &Anchor,
4686        excerpt_position: MBD,
4687        diff_transforms: &mut Cursor<
4688            DiffTransform,
4689            Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>,
4690        >,
4691    ) -> MBD
4692    where
4693        MBD: MultiBufferDimension + Ord + Sub + AddAssign<<MBD as Sub>::Output>,
4694    {
4695        loop {
4696            let transform_end_position = diff_transforms.end().0.0;
4697            let at_transform_end =
4698                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4699            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4700                diff_transforms.next();
4701                continue;
4702            }
4703
4704            let mut position = diff_transforms.start().1.0;
4705            match diff_transforms.item() {
4706                Some(DiffTransform::DeletedHunk {
4707                    buffer_id,
4708                    base_text_byte_range,
4709                    ..
4710                }) => {
4711                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4712                        && let Some(base_text) =
4713                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4714                        && base_text.can_resolve(diff_base_anchor)
4715                    {
4716                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4717                        if base_text_offset >= base_text_byte_range.start
4718                            && base_text_offset <= base_text_byte_range.end
4719                        {
4720                            let position_in_hunk = base_text
4721                                .text_summary_for_range::<MBD::TextDimension, _>(
4722                                    base_text_byte_range.start..base_text_offset,
4723                                );
4724                            position.add_text_dim(&position_in_hunk);
4725                        } else if at_transform_end {
4726                            diff_transforms.next();
4727                            continue;
4728                        }
4729                    }
4730                }
4731                _ => {
4732                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4733                        diff_transforms.next();
4734                        continue;
4735                    }
4736                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4737                    position += overshoot;
4738                }
4739            }
4740
4741            return position;
4742        }
4743    }
4744
4745    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4746        let mut cursor = self
4747            .excerpts
4748            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(());
4749        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4750
4751        cursor.seek(&Some(locator), Bias::Left);
4752        if cursor.item().is_none() && anchor.excerpt_id == ExcerptId::max() {
4753            cursor.prev();
4754        }
4755
4756        let mut position = cursor.start().1;
4757        if let Some(excerpt) = cursor.item()
4758            && (excerpt.id == anchor.excerpt_id || anchor.excerpt_id == ExcerptId::max())
4759        {
4760            let excerpt_buffer_start = excerpt
4761                .buffer
4762                .offset_for_anchor(&excerpt.range.context.start);
4763            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4764            let buffer_position = cmp::min(
4765                excerpt_buffer_end,
4766                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4767            );
4768            if buffer_position > excerpt_buffer_start {
4769                position.value += buffer_position - excerpt_buffer_start;
4770            }
4771        }
4772        position
4773    }
4774
4775    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4776        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4777            excerpt_id = *replacement;
4778        }
4779        excerpt_id
4780    }
4781
4782    pub fn summaries_for_anchors<'a, MBD, I>(&'a self, anchors: I) -> Vec<MBD>
4783    where
4784        MBD: MultiBufferDimension
4785            + Ord
4786            + Sub<Output = MBD::TextDimension>
4787            + AddAssign<MBD::TextDimension>,
4788        MBD::TextDimension: Sub<Output = MBD::TextDimension> + Ord,
4789        I: 'a + IntoIterator<Item = &'a Anchor>,
4790    {
4791        let mut anchors = anchors.into_iter().peekable();
4792        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
4793        let mut diff_transforms_cursor = self
4794            .diff_transforms
4795            .cursor::<Dimensions<ExcerptDimension<MBD>, OutputDimension<MBD>>>(());
4796        diff_transforms_cursor.next();
4797
4798        let mut summaries = Vec::new();
4799        while let Some(anchor) = anchors.peek() {
4800            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4801
4802            let excerpt_anchors = anchors.peeking_take_while(|anchor| {
4803                self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id
4804            });
4805
4806            let locator = self.excerpt_locator_for_id(excerpt_id);
4807            cursor.seek_forward(locator, Bias::Left);
4808            if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
4809                cursor.prev();
4810            }
4811
4812            let excerpt_start_position = MBD::from_summary(&cursor.start().text);
4813            if let Some(excerpt) = cursor.item() {
4814                if excerpt.id != excerpt_id && excerpt_id != ExcerptId::max() {
4815                    let position = self.resolve_summary_for_anchor(
4816                        &Anchor::min(),
4817                        excerpt_start_position,
4818                        &mut diff_transforms_cursor,
4819                    );
4820                    summaries.extend(excerpt_anchors.map(|_| position));
4821                    continue;
4822                }
4823                let excerpt_buffer_start = excerpt
4824                    .range
4825                    .context
4826                    .start
4827                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4828                let excerpt_buffer_end = excerpt
4829                    .range
4830                    .context
4831                    .end
4832                    .summary::<MBD::TextDimension>(&excerpt.buffer);
4833                for (buffer_summary, anchor) in excerpt
4834                    .buffer
4835                    .summaries_for_anchors_with_payload::<MBD::TextDimension, _, _>(
4836                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4837                    )
4838                {
4839                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4840                    let mut position = excerpt_start_position;
4841                    if summary > excerpt_buffer_start {
4842                        position += summary - excerpt_buffer_start;
4843                    }
4844
4845                    if position > diff_transforms_cursor.start().0.0 {
4846                        diff_transforms_cursor
4847                            .seek_forward(&ExcerptDimension(position), Bias::Left);
4848                    }
4849
4850                    summaries.push(self.resolve_summary_for_anchor(
4851                        anchor,
4852                        position,
4853                        &mut diff_transforms_cursor,
4854                    ));
4855                }
4856            } else {
4857                diff_transforms_cursor
4858                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
4859                let position = self.resolve_summary_for_anchor(
4860                    &Anchor::max(),
4861                    excerpt_start_position,
4862                    &mut diff_transforms_cursor,
4863                );
4864                summaries.extend(excerpt_anchors.map(|_| position));
4865            }
4866        }
4867
4868        summaries
4869    }
4870
4871    pub fn dimensions_from_points<'a, MBD>(
4872        &'a self,
4873        points: impl 'a + IntoIterator<Item = Point>,
4874    ) -> impl 'a + Iterator<Item = MBD>
4875    where
4876        MBD: MultiBufferDimension + Sub + AddAssign<<MBD as Sub>::Output>,
4877    {
4878        let mut cursor = self.cursor::<DimensionPair<Point, MBD>, Point>();
4879        cursor.seek(&DimensionPair {
4880            key: Point::default(),
4881            value: None,
4882        });
4883        let mut points = points.into_iter();
4884        iter::from_fn(move || {
4885            let point = points.next()?;
4886
4887            cursor.seek_forward(&DimensionPair {
4888                key: point,
4889                value: None,
4890            });
4891
4892            if let Some(region) = cursor.region() {
4893                let overshoot = point - region.range.start.key;
4894                let buffer_point = region.buffer_range.start + overshoot;
4895                let mut position = region.range.start.value.unwrap();
4896                position.add_text_dim(
4897                    &region
4898                        .buffer
4899                        .text_summary_for_range(region.buffer_range.start..buffer_point),
4900                );
4901                if point == region.range.end.key && region.has_trailing_newline {
4902                    position.add_mb_text_summary(&MBTextSummary::from(TextSummary::newline()));
4903                }
4904                Some(position)
4905            } else {
4906                Some(MBD::from_summary(&self.text_summary()))
4907            }
4908        })
4909    }
4910
4911    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4912    where
4913        I: 'a + IntoIterator<Item = &'a Anchor>,
4914    {
4915        let mut anchors = anchors.into_iter().enumerate().peekable();
4916        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
4917        cursor.next();
4918
4919        let mut result = Vec::new();
4920
4921        while let Some((_, anchor)) = anchors.peek() {
4922            let old_excerpt_id = anchor.excerpt_id;
4923
4924            // Find the location where this anchor's excerpt should be.
4925            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4926            cursor.seek_forward(&Some(old_locator), Bias::Left);
4927
4928            let next_excerpt = cursor.item();
4929            let prev_excerpt = cursor.prev_item();
4930
4931            // Process all of the anchors for this excerpt.
4932            while let Some((anchor_ix, &anchor)) =
4933                anchors.next_if(|(_, anchor)| anchor.excerpt_id == old_excerpt_id)
4934            {
4935                let mut anchor = anchor;
4936
4937                // Leave min and max anchors unchanged if invalid or
4938                // if the old excerpt still exists at this location
4939                let mut kept_position = next_excerpt
4940                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
4941                    || old_excerpt_id == ExcerptId::max()
4942                    || old_excerpt_id == ExcerptId::min();
4943
4944                // If the old excerpt no longer exists at this location, then attempt to
4945                // find an equivalent position for this anchor in an adjacent excerpt.
4946                if !kept_position {
4947                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
4948                        if excerpt.contains(&anchor) {
4949                            anchor.excerpt_id = excerpt.id;
4950                            kept_position = true;
4951                            break;
4952                        }
4953                    }
4954                }
4955
4956                // If there's no adjacent excerpt that contains the anchor's position,
4957                // then report that the anchor has lost its position.
4958                if !kept_position {
4959                    anchor = if let Some(excerpt) = next_excerpt {
4960                        let mut text_anchor = excerpt
4961                            .range
4962                            .context
4963                            .start
4964                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4965                        if text_anchor
4966                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
4967                            .is_gt()
4968                        {
4969                            text_anchor = excerpt.range.context.end;
4970                        }
4971                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4972                    } else if let Some(excerpt) = prev_excerpt {
4973                        let mut text_anchor = excerpt
4974                            .range
4975                            .context
4976                            .end
4977                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
4978                        if text_anchor
4979                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
4980                            .is_lt()
4981                        {
4982                            text_anchor = excerpt.range.context.start;
4983                        }
4984                        Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor)
4985                    } else if anchor.text_anchor.bias == Bias::Left {
4986                        Anchor::min()
4987                    } else {
4988                        Anchor::max()
4989                    };
4990                }
4991
4992                result.push((anchor_ix, anchor, kept_position));
4993            }
4994        }
4995        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
4996        result
4997    }
4998
4999    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5000        self.anchor_at(position, Bias::Left)
5001    }
5002
5003    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5004        self.anchor_at(position, Bias::Right)
5005    }
5006
5007    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5008        let offset = position.to_offset(self);
5009
5010        // Find the given position in the diff transforms. Determine the corresponding
5011        // offset in the excerpts, and whether the position is within a deleted hunk.
5012        let mut diff_transforms = self
5013            .diff_transforms
5014            .cursor::<Dimensions<MultiBufferOffset, ExcerptOffset>>(());
5015        diff_transforms.seek(&offset, Bias::Right);
5016
5017        if offset == diff_transforms.start().0
5018            && bias == Bias::Left
5019            && let Some(prev_item) = diff_transforms.prev_item()
5020            && let DiffTransform::DeletedHunk { .. } = prev_item
5021        {
5022            diff_transforms.prev();
5023        }
5024        let offset_in_transform = offset - diff_transforms.start().0;
5025        let mut excerpt_offset = diff_transforms.start().1;
5026        let mut diff_base_anchor = None;
5027        if let Some(DiffTransform::DeletedHunk {
5028            buffer_id,
5029            base_text_byte_range,
5030            has_trailing_newline,
5031            ..
5032        }) = diff_transforms.item()
5033        {
5034            let diff = self.diffs.get(buffer_id).expect("missing diff");
5035            if offset_in_transform > base_text_byte_range.len() {
5036                debug_assert!(*has_trailing_newline);
5037                bias = Bias::Right;
5038            } else {
5039                diff_base_anchor = Some(
5040                    diff.base_text()
5041                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5042                );
5043                bias = Bias::Left;
5044            }
5045        } else {
5046            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5047        };
5048
5049        let mut excerpts = self
5050            .excerpts
5051            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(());
5052        excerpts.seek(&excerpt_offset, Bias::Right);
5053        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5054            excerpts.prev();
5055        }
5056        if let Some(excerpt) = excerpts.item() {
5057            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5058            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5059                overshoot -= 1;
5060                bias = Bias::Right;
5061            }
5062
5063            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5064            let text_anchor =
5065                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5066            let anchor = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, text_anchor);
5067            match diff_base_anchor {
5068                Some(diff_base_anchor) => anchor.with_diff_base_anchor(diff_base_anchor),
5069                None => anchor,
5070            }
5071        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5072            Anchor::min()
5073        } else {
5074            Anchor::max()
5075        }
5076    }
5077
5078    /// Wraps the [`text::Anchor`] in a [`multi_buffer::Anchor`] if this multi-buffer is a singleton.
5079    pub fn as_singleton_anchor(&self, text_anchor: text::Anchor) -> Option<Anchor> {
5080        let (excerpt, buffer, _) = self.as_singleton()?;
5081        Some(Anchor::in_buffer(*excerpt, buffer, text_anchor))
5082    }
5083
5084    /// Returns an anchor for the given excerpt and text anchor,
5085    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5086    pub fn anchor_range_in_excerpt(
5087        &self,
5088        excerpt_id: ExcerptId,
5089        text_anchor: Range<text::Anchor>,
5090    ) -> Option<Range<Anchor>> {
5091        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5092        let excerpt = self.excerpt(excerpt_id)?;
5093
5094        Some(
5095            self.anchor_in_excerpt_(excerpt, text_anchor.start)?
5096                ..self.anchor_in_excerpt_(excerpt, text_anchor.end)?,
5097        )
5098    }
5099
5100    /// Returns an anchor for the given excerpt and text anchor,
5101    /// Returns [`None`] if the excerpt_id is no longer valid or the text anchor range is out of excerpt's bounds.
5102    pub fn anchor_in_excerpt(
5103        &self,
5104        excerpt_id: ExcerptId,
5105        text_anchor: text::Anchor,
5106    ) -> Option<Anchor> {
5107        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5108        let excerpt = self.excerpt(excerpt_id)?;
5109        self.anchor_in_excerpt_(excerpt, text_anchor)
5110    }
5111
5112    fn anchor_in_excerpt_(&self, excerpt: &Excerpt, text_anchor: text::Anchor) -> Option<Anchor> {
5113        match text_anchor.buffer_id {
5114            Some(buffer_id) if buffer_id == excerpt.buffer_id => (),
5115            Some(_) => return None,
5116            None if text_anchor == text::Anchor::MAX || text_anchor == text::Anchor::MIN => {
5117                return Some(Anchor::in_buffer(
5118                    excerpt.id,
5119                    excerpt.buffer_id,
5120                    text_anchor,
5121                ));
5122            }
5123            None => return None,
5124        }
5125
5126        let context = &excerpt.range.context;
5127        if context.start.cmp(&text_anchor, &excerpt.buffer).is_gt()
5128            || context.end.cmp(&text_anchor, &excerpt.buffer).is_lt()
5129        {
5130            return None;
5131        }
5132
5133        Some(Anchor::in_buffer(
5134            excerpt.id,
5135            excerpt.buffer_id,
5136            text_anchor,
5137        ))
5138    }
5139
5140    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5141        Some(self.excerpt(excerpt_id)?.range.context.clone())
5142    }
5143
5144    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5145        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5146            true
5147        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5148            excerpt.buffer.can_resolve(&anchor.text_anchor)
5149        } else {
5150            false
5151        }
5152    }
5153
5154    pub fn excerpts(
5155        &self,
5156    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5157        self.excerpts
5158            .iter()
5159            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5160    }
5161
5162    fn cursor<'a, MBD, BD>(&'a self) -> MultiBufferCursor<'a, MBD, BD>
5163    where
5164        MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
5165        BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
5166    {
5167        let excerpts = self.excerpts.cursor(());
5168        let diff_transforms = self.diff_transforms.cursor(());
5169        MultiBufferCursor {
5170            excerpts,
5171            diff_transforms,
5172            diffs: &self.diffs,
5173            cached_region: None,
5174        }
5175    }
5176
5177    pub fn excerpt_before(&self, excerpt_id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5178        let start_locator = self.excerpt_locator_for_id(excerpt_id);
5179        let mut excerpts = self
5180            .excerpts
5181            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<MultiBufferOffset>>>(());
5182        excerpts.seek(&Some(start_locator), Bias::Left);
5183        excerpts.prev();
5184
5185        let mut diff_transforms = self
5186            .diff_transforms
5187            .cursor::<DiffTransforms<MultiBufferOffset>>(());
5188        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5189        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5190            diff_transforms.next();
5191        }
5192
5193        let excerpt = excerpts.item()?;
5194        Some(MultiBufferExcerpt {
5195            excerpt,
5196            offset: diff_transforms.start().output_dimension.0,
5197            buffer_offset: BufferOffset(excerpt.range.context.start.to_offset(&excerpt.buffer)),
5198            excerpt_offset: excerpts.start().1.0,
5199            diff_transforms,
5200        })
5201    }
5202
5203    pub fn excerpt_boundaries_in_range<R, T>(
5204        &self,
5205        range: R,
5206    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5207    where
5208        R: RangeBounds<T>,
5209        T: ToOffset,
5210    {
5211        let start_offset;
5212        let start = match range.start_bound() {
5213            Bound::Included(start) => {
5214                start_offset = start.to_offset(self);
5215                Bound::Included(start_offset)
5216            }
5217            Bound::Excluded(_) => {
5218                panic!("not supported")
5219            }
5220            Bound::Unbounded => {
5221                start_offset = MultiBufferOffset::ZERO;
5222                Bound::Unbounded
5223            }
5224        };
5225        let end = match range.end_bound() {
5226            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5227            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5228            Bound::Unbounded => Bound::Unbounded,
5229        };
5230        let bounds = (start, end);
5231        let mut cursor = self.cursor::<DimensionPair<MultiBufferOffset, Point>, BufferOffset>();
5232        cursor.seek(&DimensionPair {
5233            key: start_offset,
5234            value: None,
5235        });
5236
5237        if cursor
5238            .region()
5239            .is_some_and(|region| bounds.contains(&region.range.start.key))
5240        {
5241            cursor.prev_excerpt();
5242        } else {
5243            cursor.seek_to_start_of_current_excerpt();
5244        }
5245        let mut prev_region = cursor.region();
5246
5247        cursor.next_excerpt();
5248
5249        iter::from_fn(move || {
5250            loop {
5251                if self.singleton {
5252                    return None;
5253                }
5254
5255                let next_region = cursor.region()?;
5256                cursor.next_excerpt();
5257                if !bounds.contains(&next_region.range.start.key) {
5258                    prev_region = Some(next_region);
5259                    continue;
5260                }
5261
5262                let next_region_start = next_region.range.start.value.unwrap();
5263                let next_region_end = if let Some(region) = cursor.region() {
5264                    region.range.start.value.unwrap()
5265                } else {
5266                    self.max_point()
5267                };
5268
5269                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5270                    id: region.excerpt.id,
5271                    buffer: region.excerpt.buffer.clone(),
5272                    buffer_id: region.excerpt.buffer_id,
5273                    range: region.excerpt.range.clone(),
5274                    end_row: MultiBufferRow(next_region_start.row),
5275                });
5276
5277                let next = ExcerptInfo {
5278                    id: next_region.excerpt.id,
5279                    buffer: next_region.excerpt.buffer.clone(),
5280                    buffer_id: next_region.excerpt.buffer_id,
5281                    range: next_region.excerpt.range.clone(),
5282                    end_row: if next_region.excerpt.has_trailing_newline {
5283                        MultiBufferRow(next_region_end.row - 1)
5284                    } else {
5285                        MultiBufferRow(next_region_end.row)
5286                    },
5287                };
5288
5289                let row = MultiBufferRow(next_region_start.row);
5290
5291                prev_region = Some(next_region);
5292
5293                return Some(ExcerptBoundary { row, prev, next });
5294            }
5295        })
5296    }
5297
5298    pub fn edit_count(&self) -> usize {
5299        self.edit_count
5300    }
5301
5302    pub fn non_text_state_update_count(&self) -> usize {
5303        self.non_text_state_update_count
5304    }
5305
5306    /// Returns the smallest enclosing bracket ranges containing the given range or
5307    /// None if no brackets contain range or the range is not contained in a single
5308    /// excerpt
5309    ///
5310    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5311    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5312        &self,
5313        range: Range<T>,
5314        range_filter: Option<
5315            &dyn Fn(&BufferSnapshot, Range<BufferOffset>, Range<BufferOffset>) -> bool,
5316        >,
5317    ) -> Option<(Range<MultiBufferOffset>, Range<MultiBufferOffset>)> {
5318        let range = range.start.to_offset(self)..range.end.to_offset(self);
5319        let mut excerpt = self.excerpt_containing(range.clone())?;
5320        let buffer = excerpt.buffer();
5321        let excerpt_buffer_range = excerpt.buffer_range();
5322
5323        // Filter to ranges contained in the excerpt
5324        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5325            excerpt_buffer_range.contains(&BufferOffset(open.start))
5326                && excerpt_buffer_range.contains(&BufferOffset(close.end))
5327                && range_filter.is_none_or(|filter| {
5328                    filter(
5329                        buffer,
5330                        BufferOffset(open.start)..BufferOffset(close.end),
5331                        BufferOffset(close.start)..BufferOffset(close.end),
5332                    )
5333                })
5334        };
5335
5336        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5337            excerpt.map_range_to_buffer(range),
5338            Some(&range_filter),
5339        )?;
5340
5341        Some((
5342            excerpt.map_range_from_buffer(BufferOffset(open.start)..BufferOffset(open.end)),
5343            excerpt.map_range_from_buffer(BufferOffset(close.start)..BufferOffset(close.end)),
5344        ))
5345    }
5346
5347    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5348    /// not contained in a single excerpt
5349    pub fn enclosing_bracket_ranges<T: ToOffset>(
5350        &self,
5351        range: Range<T>,
5352    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5353    {
5354        let range = range.start.to_offset(self)..range.end.to_offset(self);
5355        let mut excerpt = self.excerpt_containing(range.clone())?;
5356
5357        Some(
5358            excerpt
5359                .buffer()
5360                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5361                .filter_map(move |pair| {
5362                    let open_range =
5363                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5364                    let close_range =
5365                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5366                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5367                        Some((
5368                            excerpt.map_range_from_buffer(open_range),
5369                            excerpt.map_range_from_buffer(close_range),
5370                        ))
5371                    } else {
5372                        None
5373                    }
5374                }),
5375        )
5376    }
5377
5378    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5379    /// not contained in a single excerpt
5380    pub fn text_object_ranges<T: ToOffset>(
5381        &self,
5382        range: Range<T>,
5383        options: TreeSitterOptions,
5384    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, TextObject)> + '_ {
5385        let range = range.start.to_offset(self)..range.end.to_offset(self);
5386        self.excerpt_containing(range.clone())
5387            .map(|mut excerpt| {
5388                excerpt
5389                    .buffer()
5390                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5391                    .filter_map(move |(range, text_object)| {
5392                        let range = BufferOffset(range.start)..BufferOffset(range.end);
5393                        if excerpt.contains_buffer_range(range.clone()) {
5394                            Some((excerpt.map_range_from_buffer(range), text_object))
5395                        } else {
5396                            None
5397                        }
5398                    })
5399            })
5400            .into_iter()
5401            .flatten()
5402    }
5403
5404    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5405    /// not contained in a single excerpt
5406    pub fn bracket_ranges<T: ToOffset>(
5407        &self,
5408        range: Range<T>,
5409    ) -> Option<impl Iterator<Item = (Range<MultiBufferOffset>, Range<MultiBufferOffset>)> + '_>
5410    {
5411        let range = range.start.to_offset(self)..range.end.to_offset(self);
5412        let mut excerpt = self.excerpt_containing(range.clone())?;
5413
5414        Some(
5415            excerpt
5416                .buffer()
5417                .bracket_ranges(excerpt.map_range_to_buffer(range))
5418                .filter_map(move |pair| {
5419                    let open_range =
5420                        BufferOffset(pair.open_range.start)..BufferOffset(pair.open_range.end);
5421                    let close_range =
5422                        BufferOffset(pair.close_range.start)..BufferOffset(pair.close_range.end);
5423                    if excerpt.contains_buffer_range(open_range.start..close_range.end) {
5424                        Some((
5425                            excerpt.map_range_from_buffer(open_range),
5426                            excerpt.map_range_from_buffer(close_range),
5427                        ))
5428                    } else {
5429                        None
5430                    }
5431                }),
5432        )
5433    }
5434
5435    pub fn redacted_ranges<'a, T: ToOffset>(
5436        &'a self,
5437        range: Range<T>,
5438        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5439    ) -> impl Iterator<Item = Range<MultiBufferOffset>> + 'a {
5440        let range = range.start.to_offset(self)..range.end.to_offset(self);
5441        self.lift_buffer_metadata(range, move |buffer, range| {
5442            if redaction_enabled(buffer.file()) {
5443                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5444            } else {
5445                None
5446            }
5447        })
5448        .map(|(range, _, _)| range)
5449    }
5450
5451    pub fn runnable_ranges(
5452        &self,
5453        range: Range<Anchor>,
5454    ) -> impl Iterator<Item = (Range<MultiBufferOffset>, language::RunnableRange)> + '_ {
5455        let range = range.start.to_offset(self)..range.end.to_offset(self);
5456        self.lift_buffer_metadata(range, move |buffer, range| {
5457            Some(
5458                buffer
5459                    .runnable_ranges(range.clone())
5460                    .filter(move |runnable| {
5461                        runnable.run_range.start >= range.start
5462                            && runnable.run_range.end < range.end
5463                    })
5464                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5465            )
5466        })
5467        .map(|(run_range, runnable, _)| (run_range, runnable))
5468    }
5469
5470    pub fn line_indents(
5471        &self,
5472        start_row: MultiBufferRow,
5473        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5474    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5475        let max_point = self.max_point();
5476        let mut cursor = self.cursor::<Point, Point>();
5477        cursor.seek(&Point::new(start_row.0, 0));
5478        iter::from_fn(move || {
5479            let mut region = cursor.region()?;
5480            while !buffer_filter(&region.excerpt.buffer) {
5481                cursor.next();
5482                region = cursor.region()?;
5483            }
5484            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5485            let buffer_start_row =
5486                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5487
5488            let buffer_end_row = if region.is_main_buffer
5489                && (region.has_trailing_newline || region.range.end == max_point)
5490            {
5491                region.buffer_range.end.row
5492            } else {
5493                region.buffer_range.end.row.saturating_sub(1)
5494            };
5495
5496            let line_indents = region
5497                .buffer
5498                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5499            cursor.next();
5500            Some(line_indents.map(move |(buffer_row, indent)| {
5501                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5502                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5503            }))
5504        })
5505        .flatten()
5506    }
5507
5508    pub fn reversed_line_indents(
5509        &self,
5510        end_row: MultiBufferRow,
5511        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5512    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5513        let max_point = self.max_point();
5514        let mut cursor = self.cursor::<Point, Point>();
5515        cursor.seek(&Point::new(end_row.0, 0));
5516        iter::from_fn(move || {
5517            let mut region = cursor.region()?;
5518            while !buffer_filter(&region.excerpt.buffer) {
5519                cursor.prev();
5520                region = cursor.region()?;
5521            }
5522
5523            let buffer_start_row = region.buffer_range.start.row;
5524            let buffer_end_row = if region.is_main_buffer
5525                && (region.has_trailing_newline || region.range.end == max_point)
5526            {
5527                region.buffer_range.end.row + 1
5528            } else {
5529                region.buffer_range.end.row
5530            };
5531
5532            let overshoot = end_row.0 - region.range.start.row;
5533            let buffer_end_row =
5534                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5535
5536            let line_indents = region
5537                .buffer
5538                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5539            cursor.prev();
5540            Some(line_indents.map(move |(buffer_row, indent)| {
5541                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5542                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5543            }))
5544        })
5545        .flatten()
5546    }
5547
5548    pub async fn enclosing_indent(
5549        &self,
5550        mut target_row: MultiBufferRow,
5551    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5552        let max_row = MultiBufferRow(self.max_point().row);
5553        if target_row >= max_row {
5554            return None;
5555        }
5556
5557        let mut target_indent = self.line_indent_for_row(target_row);
5558
5559        // If the current row is at the start of an indented block, we want to return this
5560        // block as the enclosing indent.
5561        if !target_indent.is_line_empty() && target_row < max_row {
5562            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5563            if !next_line_indent.is_line_empty()
5564                && target_indent.raw_len() < next_line_indent.raw_len()
5565            {
5566                target_indent = next_line_indent;
5567                target_row.0 += 1;
5568            }
5569        }
5570
5571        const SEARCH_ROW_LIMIT: u32 = 25000;
5572        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5573        const YIELD_INTERVAL: u32 = 100;
5574
5575        let mut accessed_row_counter = 0;
5576
5577        // If there is a blank line at the current row, search for the next non indented lines
5578        if target_indent.is_line_empty() {
5579            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5580            let end =
5581                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5582
5583            let mut non_empty_line_above = None;
5584            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5585                if row < start {
5586                    break;
5587                }
5588                accessed_row_counter += 1;
5589                if accessed_row_counter == YIELD_INTERVAL {
5590                    accessed_row_counter = 0;
5591                    yield_now().await;
5592                }
5593                if !indent.is_line_empty() {
5594                    non_empty_line_above = Some((row, indent));
5595                    break;
5596                }
5597            }
5598
5599            let mut non_empty_line_below = None;
5600            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5601                if row > end {
5602                    break;
5603                }
5604                accessed_row_counter += 1;
5605                if accessed_row_counter == YIELD_INTERVAL {
5606                    accessed_row_counter = 0;
5607                    yield_now().await;
5608                }
5609                if !indent.is_line_empty() {
5610                    non_empty_line_below = Some((row, indent));
5611                    break;
5612                }
5613            }
5614
5615            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5616                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5617                    if above_indent.raw_len() >= below_indent.raw_len() {
5618                        (above_row, above_indent)
5619                    } else {
5620                        (below_row, below_indent)
5621                    }
5622                }
5623                (Some(above), None) => above,
5624                (None, Some(below)) => below,
5625                _ => return None,
5626            };
5627
5628            target_indent = indent;
5629            target_row = row;
5630        }
5631
5632        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5633        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5634
5635        let mut start_indent = None;
5636        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5637            if row < start {
5638                break;
5639            }
5640            accessed_row_counter += 1;
5641            if accessed_row_counter == YIELD_INTERVAL {
5642                accessed_row_counter = 0;
5643                yield_now().await;
5644            }
5645            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5646                start_indent = Some((row, indent));
5647                break;
5648            }
5649        }
5650        let (start_row, start_indent_size) = start_indent?;
5651
5652        let mut end_indent = (end, None);
5653        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5654            if row > end {
5655                break;
5656            }
5657            accessed_row_counter += 1;
5658            if accessed_row_counter == YIELD_INTERVAL {
5659                accessed_row_counter = 0;
5660                yield_now().await;
5661            }
5662            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5663                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5664                break;
5665            }
5666        }
5667        let (end_row, end_indent_size) = end_indent;
5668
5669        let indent = if let Some(end_indent_size) = end_indent_size {
5670            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5671                start_indent_size
5672            } else {
5673                end_indent_size
5674            }
5675        } else {
5676            start_indent_size
5677        };
5678
5679        Some((start_row..end_row, indent))
5680    }
5681
5682    pub fn indent_guides_in_range<T: ToPoint>(
5683        &self,
5684        range: Range<T>,
5685        ignore_disabled_for_language: bool,
5686        cx: &App,
5687    ) -> impl Iterator<Item = IndentGuide> {
5688        let range = range.start.to_point(self)..range.end.to_point(self);
5689        let start_row = MultiBufferRow(range.start.row);
5690        let end_row = MultiBufferRow(range.end.row);
5691
5692        let mut row_indents = self.line_indents(start_row, |buffer| {
5693            let settings =
5694                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5695            settings.indent_guides.enabled || ignore_disabled_for_language
5696        });
5697
5698        let mut result = Vec::new();
5699        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5700
5701        let mut prev_settings = None;
5702        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5703            if first_row > end_row {
5704                break;
5705            }
5706            let current_depth = indent_stack.len() as u32;
5707
5708            // Avoid retrieving the language settings repeatedly for every buffer row.
5709            if let Some((prev_buffer_id, _)) = &prev_settings
5710                && prev_buffer_id != &buffer.remote_id()
5711            {
5712                prev_settings.take();
5713            }
5714            let settings = &prev_settings
5715                .get_or_insert_with(|| {
5716                    (
5717                        buffer.remote_id(),
5718                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5719                    )
5720                })
5721                .1;
5722            let tab_size = settings.tab_size.get();
5723
5724            // When encountering empty, continue until found useful line indent
5725            // then add to the indent stack with the depth found
5726            let mut found_indent = false;
5727            let mut last_row = first_row;
5728            if line_indent.is_line_blank() {
5729                while !found_indent {
5730                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5731                        break;
5732                    };
5733                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5734                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5735                        break;
5736                    }
5737
5738                    if new_line_indent.is_line_blank() {
5739                        continue;
5740                    }
5741                    last_row = target_row.min(end_row);
5742                    line_indent = new_line_indent;
5743                    found_indent = true;
5744                    break;
5745                }
5746            } else {
5747                found_indent = true
5748            }
5749
5750            let depth = if found_indent {
5751                line_indent.len(tab_size) / tab_size
5752            } else {
5753                0
5754            };
5755
5756            match depth.cmp(&current_depth) {
5757                cmp::Ordering::Less => {
5758                    for _ in 0..(current_depth - depth) {
5759                        let mut indent = indent_stack.pop().unwrap();
5760                        if last_row != first_row {
5761                            // In this case, we landed on an empty row, had to seek forward,
5762                            // and discovered that the indent we where on is ending.
5763                            // This means that the last display row must
5764                            // be on line that ends this indent range, so we
5765                            // should display the range up to the first non-empty line
5766                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5767                        }
5768
5769                        result.push(indent)
5770                    }
5771                }
5772                cmp::Ordering::Greater => {
5773                    for next_depth in current_depth..depth {
5774                        indent_stack.push(IndentGuide {
5775                            buffer_id: buffer.remote_id(),
5776                            start_row: first_row,
5777                            end_row: last_row,
5778                            depth: next_depth,
5779                            tab_size,
5780                            settings: settings.indent_guides.clone(),
5781                        });
5782                    }
5783                }
5784                _ => {}
5785            }
5786
5787            for indent in indent_stack.iter_mut() {
5788                indent.end_row = last_row;
5789            }
5790        }
5791
5792        result.extend(indent_stack);
5793        result.into_iter()
5794    }
5795
5796    pub fn trailing_excerpt_update_count(&self) -> usize {
5797        self.trailing_excerpt_update_count
5798    }
5799
5800    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5801        self.point_to_buffer_offset(point)
5802            .and_then(|(buffer, _)| buffer.file())
5803    }
5804
5805    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5806        self.point_to_buffer_offset(point)
5807            .and_then(|(buffer, offset)| buffer.language_at(offset))
5808    }
5809
5810    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5811        self.excerpts
5812            .first()
5813            .map(|excerpt| &excerpt.buffer)
5814            .map(|buffer| {
5815                language_settings(
5816                    buffer.language().map(|language| language.name()),
5817                    buffer.file(),
5818                    cx,
5819                )
5820            })
5821            .unwrap_or_else(move || self.language_settings_at(MultiBufferOffset::ZERO, cx))
5822    }
5823
5824    pub fn language_settings_at<'a, T: ToOffset>(
5825        &'a self,
5826        point: T,
5827        cx: &'a App,
5828    ) -> Cow<'a, LanguageSettings> {
5829        let mut language = None;
5830        let mut file = None;
5831        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5832            language = buffer.language_at(offset);
5833            file = buffer.file();
5834        }
5835        language_settings(language.map(|l| l.name()), file, cx)
5836    }
5837
5838    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5839        self.point_to_buffer_offset(point)
5840            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5841    }
5842
5843    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5844        self.point_to_buffer_offset(point)
5845            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5846            .unwrap_or_default()
5847    }
5848
5849    pub fn language_indent_size_at<T: ToOffset>(
5850        &self,
5851        position: T,
5852        cx: &App,
5853    ) -> Option<IndentSize> {
5854        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5855        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5856    }
5857
5858    pub fn is_dirty(&self) -> bool {
5859        self.is_dirty
5860    }
5861
5862    pub fn has_deleted_file(&self) -> bool {
5863        self.has_deleted_file
5864    }
5865
5866    pub fn has_conflict(&self) -> bool {
5867        self.has_conflict
5868    }
5869
5870    pub fn has_diagnostics(&self) -> bool {
5871        self.excerpts
5872            .iter()
5873            .any(|excerpt| excerpt.buffer.has_diagnostics())
5874    }
5875
5876    pub fn diagnostic_group(
5877        &self,
5878        buffer_id: BufferId,
5879        group_id: usize,
5880    ) -> impl Iterator<Item = DiagnosticEntryRef<'_, Point>> + '_ {
5881        self.lift_buffer_metadata::<Point, _, _>(
5882            Point::zero()..self.max_point(),
5883            move |buffer, range| {
5884                if buffer.remote_id() != buffer_id {
5885                    return None;
5886                };
5887                Some(
5888                    buffer
5889                        .diagnostics_in_range(range, false)
5890                        .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
5891                        .map(move |DiagnosticEntryRef { diagnostic, range }| (range, diagnostic)),
5892                )
5893            },
5894        )
5895        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5896    }
5897
5898    pub fn diagnostics_in_range<'a, MBD>(
5899        &'a self,
5900        range: Range<MBD>,
5901    ) -> impl Iterator<Item = DiagnosticEntryRef<'a, MBD>> + 'a
5902    where
5903        MBD::TextDimension: 'a
5904            + text::ToOffset
5905            + text::FromAnchor
5906            + Sub<Output = MBD::TextDimension>
5907            + fmt::Debug
5908            + ops::Add<Output = MBD::TextDimension>
5909            + ops::AddAssign
5910            + Ord,
5911        MBD: MultiBufferDimension
5912            + Ord
5913            + Sub<Output = MBD::TextDimension>
5914            + ops::Add<MBD::TextDimension, Output = MBD>
5915            + ops::AddAssign<MBD::TextDimension>
5916            + 'a,
5917    {
5918        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
5919            Some(
5920                buffer
5921                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5922                    .map(|entry| (entry.range, entry.diagnostic)),
5923            )
5924        })
5925        .map(|(range, diagnostic, _)| DiagnosticEntryRef { diagnostic, range })
5926    }
5927
5928    pub fn diagnostics_with_buffer_ids_in_range<'a, MBD>(
5929        &'a self,
5930        range: Range<MBD>,
5931    ) -> impl Iterator<Item = (BufferId, DiagnosticEntryRef<'a, MBD>)> + 'a
5932    where
5933        MBD: MultiBufferDimension
5934            + Ord
5935            + Sub<Output = MBD::TextDimension>
5936            + ops::Add<MBD::TextDimension, Output = MBD>
5937            + ops::AddAssign<MBD::TextDimension>,
5938        MBD::TextDimension: Sub<Output = MBD::TextDimension>
5939            + ops::Add<Output = MBD::TextDimension>
5940            + text::ToOffset
5941            + text::FromAnchor
5942            + AddAssign<MBD::TextDimension>
5943            + Ord,
5944    {
5945        self.lift_buffer_metadata::<MBD, _, _>(range, move |buffer, buffer_range| {
5946            Some(
5947                buffer
5948                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5949                    .map(|entry| (entry.range, entry.diagnostic)),
5950            )
5951        })
5952        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntryRef { diagnostic, range }))
5953    }
5954
5955    pub fn syntax_ancestor<T: ToOffset>(
5956        &self,
5957        range: Range<T>,
5958    ) -> Option<(tree_sitter::Node<'_>, Range<MultiBufferOffset>)> {
5959        let range = range.start.to_offset(self)..range.end.to_offset(self);
5960        let mut excerpt = self.excerpt_containing(range.clone())?;
5961        let node = excerpt
5962            .buffer()
5963            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5964        let node_range = node.byte_range();
5965        let node_range = BufferOffset(node_range.start)..BufferOffset(node_range.end);
5966        if !excerpt.contains_buffer_range(node_range.clone()) {
5967            return None;
5968        };
5969        Some((node, excerpt.map_range_from_buffer(node_range)))
5970    }
5971
5972    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5973        let (excerpt_id, _, buffer) = self.as_singleton()?;
5974        let outline = buffer.outline(theme);
5975        Some(Outline::new(
5976            outline
5977                .items
5978                .into_iter()
5979                .flat_map(|item| {
5980                    Some(OutlineItem {
5981                        depth: item.depth,
5982                        range: self.anchor_range_in_excerpt(*excerpt_id, item.range)?,
5983                        source_range_for_text: self
5984                            .anchor_range_in_excerpt(*excerpt_id, item.source_range_for_text)?,
5985                        text: item.text,
5986                        highlight_ranges: item.highlight_ranges,
5987                        name_ranges: item.name_ranges,
5988                        body_range: item.body_range.and_then(|body_range| {
5989                            self.anchor_range_in_excerpt(*excerpt_id, body_range)
5990                        }),
5991                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5992                            self.anchor_range_in_excerpt(*excerpt_id, annotation_range)
5993                        }),
5994                    })
5995                })
5996                .collect(),
5997        ))
5998    }
5999
6000    pub fn symbols_containing<T: ToOffset>(
6001        &self,
6002        offset: T,
6003        theme: Option<&SyntaxTheme>,
6004    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6005        let anchor = self.anchor_before(offset);
6006        let excerpt_id = anchor.excerpt_id;
6007        let excerpt = self.excerpt(excerpt_id)?;
6008        let buffer_id = excerpt.buffer_id;
6009        Some((
6010            buffer_id,
6011            excerpt
6012                .buffer
6013                .symbols_containing(anchor.text_anchor, theme)
6014                .into_iter()
6015                .flat_map(|item| {
6016                    Some(OutlineItem {
6017                        depth: item.depth,
6018                        source_range_for_text: Anchor::range_in_buffer(
6019                            excerpt_id,
6020                            buffer_id,
6021                            item.source_range_for_text,
6022                        ),
6023                        range: Anchor::range_in_buffer(excerpt_id, buffer_id, item.range),
6024                        text: item.text,
6025                        highlight_ranges: item.highlight_ranges,
6026                        name_ranges: item.name_ranges,
6027                        body_range: item.body_range.map(|body_range| {
6028                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
6029                        }),
6030                        annotation_range: item.annotation_range.map(|body_range| {
6031                            Anchor::range_in_buffer(excerpt_id, buffer_id, body_range)
6032                        }),
6033                    })
6034                })
6035                .collect(),
6036        ))
6037    }
6038
6039    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6040        if id == ExcerptId::min() {
6041            Locator::min_ref()
6042        } else if id == ExcerptId::max() {
6043            Locator::max_ref()
6044        } else {
6045            let (_, _, item) = self.excerpt_ids.find::<ExcerptId, _>((), &id, Bias::Left);
6046            if let Some(entry) = item
6047                && entry.id == id
6048            {
6049                return &entry.locator;
6050            }
6051            panic!("invalid excerpt id {id:?}")
6052        }
6053    }
6054
6055    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6056    fn excerpt_locators_for_ids(
6057        &self,
6058        ids: impl IntoIterator<Item = ExcerptId>,
6059    ) -> SmallVec<[Locator; 1]> {
6060        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6061        sorted_ids.sort_unstable();
6062        sorted_ids.dedup();
6063        let mut locators = SmallVec::new();
6064
6065        while sorted_ids.last() == Some(&ExcerptId::max()) {
6066            sorted_ids.pop();
6067            locators.push(Locator::max());
6068        }
6069
6070        let mut sorted_ids = sorted_ids.into_iter().peekable();
6071        locators.extend(
6072            sorted_ids
6073                .peeking_take_while(|excerpt| *excerpt == ExcerptId::min())
6074                .map(|_| Locator::min()),
6075        );
6076
6077        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(());
6078        for id in sorted_ids {
6079            if cursor.seek_forward(&id, Bias::Left) {
6080                locators.push(cursor.item().unwrap().locator.clone());
6081            } else {
6082                panic!("invalid excerpt id {:?}", id);
6083            }
6084        }
6085
6086        locators.sort_unstable();
6087        locators
6088    }
6089
6090    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6091        Some(self.excerpt(excerpt_id)?.buffer_id)
6092    }
6093
6094    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6095        Some(&self.excerpt(excerpt_id)?.buffer)
6096    }
6097
6098    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6099        let mut cursor = self
6100            .excerpts
6101            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(());
6102        let locator = self.excerpt_locator_for_id(excerpt_id);
6103        let mut sought_exact = cursor.seek(&Some(locator), Bias::Left);
6104        if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6105            sought_exact = true;
6106            cursor.prev();
6107        } else if excerpt_id == ExcerptId::min() {
6108            sought_exact = true;
6109        }
6110        if sought_exact {
6111            let start = cursor.start().1;
6112            let end = cursor.end().1;
6113            let mut diff_transforms = self
6114                .diff_transforms
6115                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(());
6116            diff_transforms.seek(&start, Bias::Left);
6117            let overshoot = start.0 - diff_transforms.start().0.0;
6118            let start = diff_transforms.start().1.0 + overshoot;
6119            diff_transforms.seek(&end, Bias::Right);
6120            let overshoot = end.0 - diff_transforms.start().0.0;
6121            let end = diff_transforms.start().1.0 + overshoot;
6122            Some(start..end)
6123        } else {
6124            None
6125        }
6126    }
6127
6128    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6129        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(());
6130        let locator = self.excerpt_locator_for_id(excerpt_id);
6131        cursor.seek(&Some(locator), Bias::Left);
6132        if let Some(excerpt) = cursor.item()
6133            && excerpt.id == excerpt_id
6134        {
6135            return Some(excerpt);
6136        } else if cursor.item().is_none() && excerpt_id == ExcerptId::max() {
6137            cursor.prev();
6138            return cursor.item();
6139        }
6140        None
6141    }
6142
6143    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6144    pub fn excerpt_containing<T: ToOffset>(
6145        &self,
6146        range: Range<T>,
6147    ) -> Option<MultiBufferExcerpt<'_>> {
6148        let range = range.start.to_offset(self)..range.end.to_offset(self);
6149        let mut cursor = self.cursor::<MultiBufferOffset, BufferOffset>();
6150        cursor.seek(&range.start);
6151
6152        let start_excerpt = cursor.excerpt()?;
6153        if range.end != range.start {
6154            cursor.seek_forward(&range.end);
6155            if cursor.excerpt()?.id != start_excerpt.id {
6156                return None;
6157            }
6158        }
6159
6160        cursor.seek_to_start_of_current_excerpt();
6161        let region = cursor.region()?;
6162        let offset = region.range.start;
6163        let buffer_offset = start_excerpt.buffer_start_offset();
6164        let excerpt_offset = cursor.excerpts.start().0;
6165        Some(MultiBufferExcerpt {
6166            diff_transforms: cursor.diff_transforms,
6167            excerpt: start_excerpt,
6168            offset,
6169            buffer_offset,
6170            excerpt_offset,
6171        })
6172    }
6173
6174    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6175        if let Some(id) = anchor.buffer_id {
6176            return Some(id);
6177        }
6178        let excerpt = self.excerpt_containing(anchor..anchor)?;
6179        Some(excerpt.buffer_id())
6180    }
6181
6182    pub fn selections_in_range<'a>(
6183        &'a self,
6184        range: &'a Range<Anchor>,
6185        include_local: bool,
6186    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6187        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(());
6188        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6189        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6190        cursor.seek(start_locator, Bias::Left);
6191        cursor
6192            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6193            .flat_map(move |excerpt| {
6194                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6195                if excerpt.id == range.start.excerpt_id {
6196                    query_range.start = range.start.text_anchor;
6197                }
6198                if excerpt.id == range.end.excerpt_id {
6199                    query_range.end = range.end.text_anchor;
6200                }
6201
6202                excerpt
6203                    .buffer
6204                    .selections_in_range(query_range, include_local)
6205                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6206                        selections.map(move |selection| {
6207                            let mut start =
6208                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.start);
6209                            let mut end =
6210                                Anchor::in_buffer(excerpt.id, excerpt.buffer_id, selection.end);
6211                            if range.start.cmp(&start, self).is_gt() {
6212                                start = range.start;
6213                            }
6214                            if range.end.cmp(&end, self).is_lt() {
6215                                end = range.end;
6216                            }
6217
6218                            (
6219                                replica_id,
6220                                line_mode,
6221                                cursor_shape,
6222                                Selection {
6223                                    id: selection.id,
6224                                    start,
6225                                    end,
6226                                    reversed: selection.reversed,
6227                                    goal: selection.goal,
6228                                },
6229                            )
6230                        })
6231                    })
6232            })
6233    }
6234
6235    pub fn show_headers(&self) -> bool {
6236        self.show_headers
6237    }
6238
6239    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6240        self.diffs.get(&buffer_id)
6241    }
6242
6243    /// Visually annotates a position or range with the `Debug` representation of a value. The
6244    /// callsite of this function is used as a key - previous annotations will be removed.
6245    #[cfg(debug_assertions)]
6246    #[track_caller]
6247    pub fn debug<V, R>(&self, ranges: &R, value: V)
6248    where
6249        R: debug::ToMultiBufferDebugRanges,
6250        V: std::fmt::Debug,
6251    {
6252        self.debug_with_key(std::panic::Location::caller(), ranges, value);
6253    }
6254
6255    /// Visually annotates a position or range with the `Debug` representation of a value. Previous
6256    /// debug annotations with the same key will be removed. The key is also used to determine the
6257    /// annotation's color.
6258    #[cfg(debug_assertions)]
6259    #[track_caller]
6260    pub fn debug_with_key<K, R, V>(&self, key: &K, ranges: &R, value: V)
6261    where
6262        K: std::hash::Hash + 'static,
6263        R: debug::ToMultiBufferDebugRanges,
6264        V: std::fmt::Debug,
6265    {
6266        let text_ranges = ranges
6267            .to_multi_buffer_debug_ranges(self)
6268            .into_iter()
6269            .flat_map(|range| {
6270                self.range_to_buffer_ranges(range).into_iter().map(
6271                    |(buffer, range, _excerpt_id)| {
6272                        buffer.anchor_after(range.start)..buffer.anchor_before(range.end)
6273                    },
6274                )
6275            })
6276            .collect();
6277        text::debug::GlobalDebugRanges::with_locked(|debug_ranges| {
6278            debug_ranges.insert(key, text_ranges, format!("{value:?}").into())
6279        });
6280    }
6281}
6282
6283#[cfg(any(test, feature = "test-support"))]
6284impl MultiBufferSnapshot {
6285    pub fn random_byte_range(
6286        &self,
6287        start_offset: MultiBufferOffset,
6288        rng: &mut impl rand::Rng,
6289    ) -> Range<MultiBufferOffset> {
6290        let end = self.clip_offset(rng.random_range(start_offset..=self.len()), Bias::Right);
6291        let start = self.clip_offset(rng.random_range(start_offset..=end), Bias::Right);
6292        start..end
6293    }
6294
6295    #[cfg(any(test, feature = "test-support"))]
6296    fn check_invariants(&self) {
6297        let excerpts = self.excerpts.items(());
6298        let excerpt_ids = self.excerpt_ids.items(());
6299
6300        for (ix, excerpt) in excerpts.iter().enumerate() {
6301            if ix == 0 {
6302                if excerpt.locator <= Locator::min() {
6303                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6304                }
6305            } else if excerpt.locator <= excerpts[ix - 1].locator {
6306                panic!("excerpts are out-of-order: {:?}", excerpts);
6307            }
6308        }
6309
6310        for (ix, entry) in excerpt_ids.iter().enumerate() {
6311            if ix == 0 {
6312                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6313                    panic!("invalid first excerpt id {:?}", entry.id);
6314                }
6315            } else if entry.id <= excerpt_ids[ix - 1].id {
6316                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6317            }
6318        }
6319
6320        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6321            panic!(
6322                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6323                self.excerpts.summary().text,
6324                self.diff_transforms.summary().input,
6325                self.diff_transforms.items(()),
6326            );
6327        }
6328
6329        let mut prev_transform: Option<&DiffTransform> = None;
6330        for item in self.diff_transforms.iter() {
6331            if let DiffTransform::BufferContent {
6332                summary,
6333                inserted_hunk_info,
6334            } = item
6335            {
6336                if let Some(DiffTransform::BufferContent {
6337                    inserted_hunk_info: prev_inserted_hunk_info,
6338                    ..
6339                }) = prev_transform
6340                    && *inserted_hunk_info == *prev_inserted_hunk_info
6341                {
6342                    panic!(
6343                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6344                        self.diff_transforms.items(())
6345                    );
6346                }
6347                if summary.len == MultiBufferOffset(0) && !self.is_empty() {
6348                    panic!("empty buffer content transform");
6349                }
6350            }
6351            prev_transform = Some(item);
6352        }
6353    }
6354}
6355
6356impl<'a, MBD, BD> MultiBufferCursor<'a, MBD, BD>
6357where
6358    MBD: MultiBufferDimension + Ord + Sub + ops::AddAssign<<MBD as Sub>::Output>,
6359    BD: TextDimension + AddAssign<<MBD as Sub>::Output>,
6360{
6361    fn seek(&mut self, position: &MBD) {
6362        self.cached_region.take();
6363        self.diff_transforms
6364            .seek(&OutputDimension(*position), Bias::Right);
6365        if self.diff_transforms.item().is_none()
6366            && *position == self.diff_transforms.start().output_dimension.0
6367        {
6368            self.diff_transforms.prev();
6369        }
6370
6371        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6372        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6373            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6374            excerpt_position.0 += overshoot;
6375        }
6376
6377        self.excerpts.seek(&excerpt_position, Bias::Right);
6378        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6379            self.excerpts.prev();
6380        }
6381    }
6382
6383    fn seek_forward(&mut self, position: &MBD) {
6384        self.cached_region.take();
6385        self.diff_transforms
6386            .seek_forward(&OutputDimension(*position), Bias::Right);
6387        if self.diff_transforms.item().is_none()
6388            && *position == self.diff_transforms.start().output_dimension.0
6389        {
6390            self.diff_transforms.prev();
6391        }
6392
6393        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6394        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension;
6395        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6396            excerpt_position.0 += overshoot;
6397        }
6398
6399        self.excerpts.seek_forward(&excerpt_position, Bias::Right);
6400        if self.excerpts.item().is_none() && excerpt_position == *self.excerpts.start() {
6401            self.excerpts.prev();
6402        }
6403    }
6404
6405    fn next_excerpt(&mut self) {
6406        self.excerpts.next();
6407        self.seek_to_start_of_current_excerpt();
6408    }
6409
6410    fn prev_excerpt(&mut self) {
6411        self.excerpts.prev();
6412        self.seek_to_start_of_current_excerpt();
6413    }
6414
6415    fn seek_to_start_of_current_excerpt(&mut self) {
6416        self.cached_region.take();
6417        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6418        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6419            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6420            && self.diff_transforms.next_item().is_some()
6421        {
6422            self.diff_transforms.next();
6423        }
6424    }
6425
6426    fn next(&mut self) {
6427        self.cached_region.take();
6428        match self
6429            .diff_transforms
6430            .end()
6431            .excerpt_dimension
6432            .cmp(&self.excerpts.end())
6433        {
6434            cmp::Ordering::Less => self.diff_transforms.next(),
6435            cmp::Ordering::Greater => self.excerpts.next(),
6436            cmp::Ordering::Equal => {
6437                self.diff_transforms.next();
6438                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6439                    || self.diff_transforms.item().is_none()
6440                {
6441                    self.excerpts.next();
6442                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6443                    self.diff_transforms.item()
6444                    && self
6445                        .excerpts
6446                        .item()
6447                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6448                {
6449                    self.excerpts.next();
6450                }
6451            }
6452        }
6453    }
6454
6455    fn prev(&mut self) {
6456        self.cached_region.take();
6457        match self
6458            .diff_transforms
6459            .start()
6460            .excerpt_dimension
6461            .cmp(self.excerpts.start())
6462        {
6463            cmp::Ordering::Less => self.excerpts.prev(),
6464            cmp::Ordering::Greater => self.diff_transforms.prev(),
6465            cmp::Ordering::Equal => {
6466                self.diff_transforms.prev();
6467                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6468                    || self.diff_transforms.item().is_none()
6469                {
6470                    self.excerpts.prev();
6471                }
6472            }
6473        }
6474    }
6475
6476    fn region(&mut self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6477        if self.cached_region.is_none() {
6478            self.cached_region = self.build_region();
6479        }
6480        self.cached_region.clone()
6481    }
6482
6483    fn is_at_start_of_excerpt(&mut self) -> bool {
6484        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6485            return false;
6486        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6487            return true;
6488        }
6489
6490        self.diff_transforms.prev();
6491        let prev_transform = self.diff_transforms.item();
6492        self.diff_transforms.next();
6493
6494        prev_transform.is_none_or(|next_transform| {
6495            matches!(next_transform, DiffTransform::BufferContent { .. })
6496        })
6497    }
6498
6499    fn is_at_end_of_excerpt(&mut self) -> bool {
6500        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6501            return false;
6502        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6503            || self.diff_transforms.item().is_none()
6504        {
6505            return true;
6506        }
6507
6508        let next_transform = self.diff_transforms.next_item();
6509        next_transform.is_none_or(|next_transform| match next_transform {
6510            DiffTransform::BufferContent { .. } => true,
6511            DiffTransform::DeletedHunk { hunk_info, .. } => self
6512                .excerpts
6513                .item()
6514                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6515        })
6516    }
6517
6518    fn main_buffer_position(&self) -> Option<BD> {
6519        let excerpt = self.excerpts.item()?;
6520        let buffer = &excerpt.buffer;
6521        let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6522        let mut buffer_start = buffer_context_start;
6523        let overshoot = self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6524        buffer_start += overshoot.0;
6525        Some(buffer_start)
6526    }
6527
6528    fn build_region(&self) -> Option<MultiBufferRegion<'a, MBD, BD>> {
6529        let excerpt = self.excerpts.item()?;
6530        match self.diff_transforms.item()? {
6531            DiffTransform::DeletedHunk {
6532                buffer_id,
6533                base_text_byte_range,
6534                has_trailing_newline,
6535                hunk_info,
6536                ..
6537            } => {
6538                let diff = self.diffs.get(buffer_id)?;
6539                let buffer = diff.base_text();
6540                let mut rope_cursor = buffer.as_rope().cursor(0);
6541                let buffer_start = rope_cursor.summary::<BD>(base_text_byte_range.start);
6542                let buffer_range_len = rope_cursor.summary::<BD>(base_text_byte_range.end);
6543                let mut buffer_end = buffer_start;
6544                TextDimension::add_assign(&mut buffer_end, &buffer_range_len);
6545                let start = self.diff_transforms.start().output_dimension.0;
6546                let end = self.diff_transforms.end().output_dimension.0;
6547                Some(MultiBufferRegion {
6548                    buffer,
6549                    excerpt,
6550                    has_trailing_newline: *has_trailing_newline,
6551                    is_main_buffer: false,
6552                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6553                        hunk_info.hunk_secondary_status,
6554                    )),
6555                    buffer_range: buffer_start..buffer_end,
6556                    range: start..end,
6557                })
6558            }
6559            DiffTransform::BufferContent {
6560                inserted_hunk_info, ..
6561            } => {
6562                let buffer = &excerpt.buffer;
6563                let buffer_context_start = excerpt.range.context.start.summary::<BD>(buffer);
6564
6565                let mut start = self.diff_transforms.start().output_dimension.0;
6566                let mut buffer_start = buffer_context_start;
6567                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6568                    let overshoot =
6569                        *self.excerpts.start() - self.diff_transforms.start().excerpt_dimension;
6570                    start += overshoot.0;
6571                } else {
6572                    let overshoot =
6573                        self.diff_transforms.start().excerpt_dimension - *self.excerpts.start();
6574                    buffer_start += overshoot.0;
6575                }
6576
6577                let mut end;
6578                let mut buffer_end;
6579                let has_trailing_newline;
6580                if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6581                    let overshoot =
6582                        self.diff_transforms.end().excerpt_dimension - *self.excerpts.start();
6583                    end = self.diff_transforms.end().output_dimension.0;
6584                    buffer_end = buffer_context_start;
6585                    buffer_end += overshoot.0;
6586                    has_trailing_newline = false;
6587                } else {
6588                    let overshoot =
6589                        self.excerpts.end() - self.diff_transforms.start().excerpt_dimension;
6590                    end = self.diff_transforms.start().output_dimension.0;
6591                    end += overshoot.0;
6592                    buffer_end = excerpt.range.context.end.summary::<BD>(buffer);
6593                    has_trailing_newline = excerpt.has_trailing_newline;
6594                };
6595
6596                Some(MultiBufferRegion {
6597                    buffer,
6598                    excerpt,
6599                    has_trailing_newline,
6600                    is_main_buffer: true,
6601                    diff_hunk_status: inserted_hunk_info
6602                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6603                    buffer_range: buffer_start..buffer_end,
6604                    range: start..end,
6605                })
6606            }
6607        }
6608    }
6609
6610    fn excerpt(&self) -> Option<&'a Excerpt> {
6611        self.excerpts.item()
6612    }
6613}
6614
6615impl Excerpt {
6616    fn new(
6617        id: ExcerptId,
6618        locator: Locator,
6619        buffer_id: BufferId,
6620        buffer: BufferSnapshot,
6621        range: ExcerptRange<text::Anchor>,
6622        has_trailing_newline: bool,
6623    ) -> Self {
6624        Excerpt {
6625            id,
6626            locator,
6627            max_buffer_row: range.context.end.to_point(&buffer).row,
6628            text_summary: buffer
6629                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6630            buffer_id,
6631            buffer,
6632            range,
6633            has_trailing_newline,
6634        }
6635    }
6636
6637    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6638        let content_start = self.range.context.start.to_offset(&self.buffer);
6639        let chunks_start = content_start + range.start;
6640        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6641
6642        let has_footer = self.has_trailing_newline
6643            && range.start <= self.text_summary.len
6644            && range.end > self.text_summary.len;
6645
6646        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6647
6648        ExcerptChunks {
6649            excerpt_id: self.id,
6650            content_chunks,
6651            has_footer,
6652        }
6653    }
6654
6655    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6656        let content_start = self.range.context.start.to_offset(&self.buffer);
6657        let chunks_start = content_start + range.start;
6658        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6659        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6660        excerpt_chunks.has_footer = self.has_trailing_newline
6661            && range.start <= self.text_summary.len
6662            && range.end > self.text_summary.len;
6663    }
6664
6665    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6666        if text_anchor
6667            .cmp(&self.range.context.start, &self.buffer)
6668            .is_lt()
6669        {
6670            self.range.context.start
6671        } else if text_anchor
6672            .cmp(&self.range.context.end, &self.buffer)
6673            .is_gt()
6674        {
6675            self.range.context.end
6676        } else {
6677            text_anchor
6678        }
6679    }
6680
6681    fn contains(&self, anchor: &Anchor) -> bool {
6682        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
6683            && self
6684                .range
6685                .context
6686                .start
6687                .cmp(&anchor.text_anchor, &self.buffer)
6688                .is_le()
6689            && self
6690                .range
6691                .context
6692                .end
6693                .cmp(&anchor.text_anchor, &self.buffer)
6694                .is_ge()
6695    }
6696
6697    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6698    fn buffer_start_offset(&self) -> BufferOffset {
6699        BufferOffset(self.range.context.start.to_offset(&self.buffer))
6700    }
6701
6702    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6703    fn buffer_end_offset(&self) -> BufferOffset {
6704        self.buffer_start_offset() + self.text_summary.len
6705    }
6706}
6707
6708impl<'a> MultiBufferExcerpt<'a> {
6709    pub fn id(&self) -> ExcerptId {
6710        self.excerpt.id
6711    }
6712
6713    pub fn buffer_id(&self) -> BufferId {
6714        self.excerpt.buffer_id
6715    }
6716
6717    pub fn start_anchor(&self) -> Anchor {
6718        Anchor::in_buffer(
6719            self.excerpt.id,
6720            self.excerpt.buffer_id,
6721            self.excerpt.range.context.start,
6722        )
6723    }
6724
6725    pub fn end_anchor(&self) -> Anchor {
6726        Anchor::in_buffer(
6727            self.excerpt.id,
6728            self.excerpt.buffer_id,
6729            self.excerpt.range.context.end,
6730        )
6731    }
6732
6733    pub fn buffer(&self) -> &'a BufferSnapshot {
6734        &self.excerpt.buffer
6735    }
6736
6737    pub fn buffer_range(&self) -> Range<BufferOffset> {
6738        self.buffer_offset
6739            ..BufferOffset(
6740                self.excerpt
6741                    .range
6742                    .context
6743                    .end
6744                    .to_offset(&self.excerpt.buffer.text),
6745            )
6746    }
6747
6748    pub fn start_offset(&self) -> MultiBufferOffset {
6749        self.offset
6750    }
6751
6752    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6753    pub fn map_offset_to_buffer(&mut self, offset: MultiBufferOffset) -> BufferOffset {
6754        self.map_range_to_buffer(offset..offset).start
6755    }
6756
6757    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6758    pub fn map_range_to_buffer(&mut self, range: Range<MultiBufferOffset>) -> Range<BufferOffset> {
6759        self.diff_transforms
6760            .seek(&OutputDimension(range.start), Bias::Right);
6761        let start = self.map_offset_to_buffer_internal(range.start);
6762        let end = if range.end > range.start {
6763            self.diff_transforms
6764                .seek_forward(&OutputDimension(range.end), Bias::Right);
6765            self.map_offset_to_buffer_internal(range.end)
6766        } else {
6767            start
6768        };
6769        start..end
6770    }
6771
6772    fn map_offset_to_buffer_internal(&self, offset: MultiBufferOffset) -> BufferOffset {
6773        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension;
6774        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6775            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
6776        };
6777        let offset_in_excerpt = excerpt_offset.0.0.saturating_sub(self.excerpt_offset.0);
6778        self.buffer_offset + offset_in_excerpt
6779    }
6780
6781    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6782    pub fn map_offset_from_buffer(&mut self, buffer_offset: BufferOffset) -> MultiBufferOffset {
6783        self.map_range_from_buffer(buffer_offset..buffer_offset)
6784            .start
6785    }
6786
6787    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6788    pub fn map_range_from_buffer(
6789        &mut self,
6790        buffer_range: Range<BufferOffset>,
6791    ) -> Range<MultiBufferOffset> {
6792        if buffer_range.start < self.buffer_offset {
6793            log::warn!(
6794                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6795            );
6796            return self.offset..self.offset;
6797        }
6798        let overshoot = buffer_range.start - self.buffer_offset;
6799        let excerpt_offset = self.excerpt_offset + overshoot;
6800        let excerpt_seek_dim = ExcerptDimension(excerpt_offset);
6801        self.diff_transforms.seek(&excerpt_seek_dim, Bias::Right);
6802        if excerpt_offset < self.diff_transforms.start().excerpt_dimension.0 {
6803            log::warn!(
6804                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6805            );
6806            return self.offset..self.offset;
6807        }
6808        let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension.0;
6809        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
6810
6811        let end = if buffer_range.end > buffer_range.start {
6812            let overshoot = buffer_range.end - self.buffer_offset;
6813            let excerpt_offset = self.excerpt_offset + overshoot;
6814            let excerpt_seek_dim = ExcerptDimension(excerpt_offset);
6815            self.diff_transforms
6816                .seek_forward(&excerpt_seek_dim, Bias::Right);
6817            let overshoot = excerpt_offset - self.diff_transforms.start().excerpt_dimension.0;
6818            self.diff_transforms.start().output_dimension.0 + overshoot
6819        } else {
6820            start
6821        };
6822
6823        start..end
6824    }
6825
6826    /// Returns true if the entirety of the given range is in the buffer's excerpt
6827    pub fn contains_buffer_range(&self, range: Range<BufferOffset>) -> bool {
6828        range.start >= self.excerpt.buffer_start_offset()
6829            && range.end <= self.excerpt.buffer_end_offset()
6830    }
6831
6832    pub fn max_buffer_row(&self) -> u32 {
6833        self.excerpt.max_buffer_row
6834    }
6835}
6836
6837impl ExcerptId {
6838    pub fn min() -> Self {
6839        Self(0)
6840    }
6841
6842    pub fn max() -> Self {
6843        Self(u32::MAX)
6844    }
6845
6846    pub fn to_proto(self) -> u64 {
6847        self.0 as _
6848    }
6849
6850    pub fn from_proto(proto: u64) -> Self {
6851        Self(proto as _)
6852    }
6853
6854    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6855        let a = snapshot.excerpt_locator_for_id(*self);
6856        let b = snapshot.excerpt_locator_for_id(*other);
6857        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6858    }
6859}
6860
6861impl From<ExcerptId> for usize {
6862    fn from(val: ExcerptId) -> Self {
6863        val.0 as usize
6864    }
6865}
6866
6867impl fmt::Debug for Excerpt {
6868    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
6869        f.debug_struct("Excerpt")
6870            .field("id", &self.id)
6871            .field("locator", &self.locator)
6872            .field("buffer_id", &self.buffer_id)
6873            .field("range", &self.range)
6874            .field("text_summary", &self.text_summary)
6875            .field("has_trailing_newline", &self.has_trailing_newline)
6876            .finish()
6877    }
6878}
6879
6880impl sum_tree::Item for Excerpt {
6881    type Summary = ExcerptSummary;
6882
6883    fn summary(&self, _cx: ()) -> Self::Summary {
6884        let mut text = self.text_summary;
6885        if self.has_trailing_newline {
6886            text += TextSummary::from("\n");
6887        }
6888        ExcerptSummary {
6889            excerpt_id: self.id,
6890            excerpt_locator: self.locator.clone(),
6891            widest_line_number: self.max_buffer_row,
6892            text: text.into(),
6893        }
6894    }
6895}
6896
6897impl sum_tree::Item for ExcerptIdMapping {
6898    type Summary = ExcerptId;
6899
6900    fn summary(&self, _cx: ()) -> Self::Summary {
6901        self.id
6902    }
6903}
6904
6905impl sum_tree::KeyedItem for ExcerptIdMapping {
6906    type Key = ExcerptId;
6907
6908    fn key(&self) -> Self::Key {
6909        self.id
6910    }
6911}
6912
6913impl DiffTransform {
6914    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
6915        match self {
6916            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
6917            DiffTransform::BufferContent {
6918                inserted_hunk_info, ..
6919            } => *inserted_hunk_info,
6920        }
6921    }
6922}
6923
6924impl sum_tree::Item for DiffTransform {
6925    type Summary = DiffTransformSummary;
6926
6927    fn summary(&self, _: <Self::Summary as sum_tree::Summary>::Context<'_>) -> Self::Summary {
6928        match self {
6929            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
6930                input: *summary,
6931                output: *summary,
6932            },
6933            &DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
6934                input: MBTextSummary::default(),
6935                output: summary.into(),
6936            },
6937        }
6938    }
6939}
6940
6941impl DiffTransformSummary {
6942    fn excerpt_len(&self) -> ExcerptOffset {
6943        ExcerptOffset::new(self.input.len.0)
6944    }
6945}
6946
6947impl sum_tree::ContextLessSummary for DiffTransformSummary {
6948    fn zero() -> Self {
6949        DiffTransformSummary {
6950            input: MBTextSummary::default(),
6951            output: MBTextSummary::default(),
6952        }
6953    }
6954
6955    fn add_summary(&mut self, other: &Self) {
6956        self.input += other.input;
6957        self.output += other.output;
6958    }
6959}
6960
6961impl sum_tree::ContextLessSummary for ExcerptId {
6962    fn zero() -> Self {
6963        Self(0)
6964    }
6965
6966    fn add_summary(&mut self, summary: &Self) {
6967        *self = cmp::max(*self, *summary);
6968    }
6969}
6970
6971impl sum_tree::ContextLessSummary for ExcerptSummary {
6972    fn zero() -> Self {
6973        Self::default()
6974    }
6975
6976    fn add_summary(&mut self, summary: &Self) {
6977        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
6978        self.excerpt_locator = summary.excerpt_locator.clone();
6979        self.text += summary.text;
6980        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
6981    }
6982}
6983
6984impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
6985    fn zero(_cx: ()) -> Self {
6986        Default::default()
6987    }
6988
6989    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
6990        self.value += summary.text.len.0;
6991    }
6992}
6993impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for MultiBufferOffset {
6994    fn zero((): ()) -> Self {
6995        Default::default()
6996    }
6997
6998    fn add_summary(&mut self, summary: &'a ExcerptSummary, (): ()) {
6999        *self += summary.text.len;
7000    }
7001}
7002
7003impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for MultiBufferOffsetUtf16 {
7004    fn zero((): ()) -> Self {
7005        Default::default()
7006    }
7007
7008    fn add_summary(&mut self, summary: &'a ExcerptSummary, (): ()) {
7009        self.0 += summary.text.len_utf16;
7010    }
7011}
7012impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
7013    fn zero((): ()) -> Self {
7014        Default::default()
7015    }
7016
7017    fn add_summary(&mut self, summary: &'a ExcerptSummary, (): ()) {
7018        TextDimension::add_assign(self, &summary.text.lines_utf16())
7019    }
7020}
7021
7022impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7023    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7024        Ord::cmp(&self.value, &cursor_location.text.len.0)
7025    }
7026}
7027
7028impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7029    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: ()) -> cmp::Ordering {
7030        Ord::cmp(&Some(self), cursor_location)
7031    }
7032}
7033
7034impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7035    fn cmp(&self, cursor_location: &ExcerptSummary, _: ()) -> cmp::Ordering {
7036        Ord::cmp(self, &cursor_location.excerpt_locator)
7037    }
7038}
7039
7040impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7041    fn zero(_cx: ()) -> Self {
7042        Default::default()
7043    }
7044
7045    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7046        self.value += summary.text.lines;
7047    }
7048}
7049
7050impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
7051    fn zero(_cx: ()) -> Self {
7052        Default::default()
7053    }
7054
7055    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7056        TextDimension::add_assign(self, &summary.text.lines);
7057    }
7058}
7059
7060impl<'a, MBD: MultiBufferDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7061    for ExcerptDimension<MBD>
7062{
7063    fn zero(_: ()) -> Self {
7064        ExcerptDimension(MBD::default())
7065    }
7066
7067    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7068        MultiBufferDimension::add_mb_text_summary(&mut self.0, &summary.text)
7069    }
7070}
7071
7072impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7073    fn zero(_cx: ()) -> Self {
7074        Default::default()
7075    }
7076
7077    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7078        *self = Some(&summary.excerpt_locator);
7079    }
7080}
7081
7082impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7083    fn zero(_cx: ()) -> Self {
7084        Default::default()
7085    }
7086
7087    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: ()) {
7088        *self = Some(summary.excerpt_id);
7089    }
7090}
7091
7092#[derive(Copy, Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7093struct ExcerptDimension<T>(T);
7094
7095impl<R, T: ops::Sub> ops::Sub for ExcerptDimension<T>
7096where
7097    T: ops::Sub<Output = R>,
7098{
7099    type Output = ExcerptDimension<R>;
7100
7101    fn sub(self, other: Self) -> Self::Output {
7102        ExcerptDimension(self.0 - other.0)
7103    }
7104}
7105
7106impl<T> AddAssign for ExcerptDimension<T>
7107where
7108    T: AddAssign,
7109{
7110    fn add_assign(&mut self, other: Self) {
7111        self.0 += other.0;
7112    }
7113}
7114
7115#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7116struct OutputDimension<T>(T);
7117
7118impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffset {
7119    fn zero(_: ()) -> Self {
7120        MultiBufferOffset::ZERO
7121    }
7122
7123    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7124        *self += summary.output.len;
7125    }
7126}
7127
7128impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for MultiBufferOffsetUtf16 {
7129    fn zero(_: ()) -> Self {
7130        MultiBufferOffsetUtf16(OffsetUtf16(0))
7131    }
7132
7133    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7134        self.0 += summary.output.len_utf16;
7135    }
7136}
7137
7138impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7139    fn zero(_: ()) -> Self {
7140        ExcerptOffset::new(0)
7141    }
7142
7143    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7144        self.value += summary.input.len.0;
7145    }
7146}
7147
7148impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7149    fn zero(_: ()) -> Self {
7150        ExcerptPoint::new(0, 0)
7151    }
7152
7153    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7154        self.value += summary.input.lines;
7155    }
7156}
7157
7158impl<MBD> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7159    for ExcerptDimension<MBD>
7160where
7161    MBD: MultiBufferDimension + Ord,
7162{
7163    fn cmp(&self, cursor_location: &DiffTransformSummary, _: ()) -> cmp::Ordering {
7164        Ord::cmp(&self.0, &MBD::from_summary(&cursor_location.input))
7165    }
7166}
7167
7168impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7169    for ExcerptDimension<MBD>
7170where
7171    MBD: MultiBufferDimension + Ord,
7172{
7173    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7174        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7175    }
7176}
7177
7178impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7179    for ExcerptDimension<MBD>
7180{
7181    fn zero(_: ()) -> Self {
7182        ExcerptDimension(MBD::default())
7183    }
7184
7185    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7186        self.0.add_mb_text_summary(&summary.input)
7187    }
7188}
7189
7190impl<'a, MBD> sum_tree::SeekTarget<'a, DiffTransformSummary, DiffTransforms<MBD>>
7191    for OutputDimension<MBD>
7192where
7193    MBD: MultiBufferDimension + Ord,
7194{
7195    fn cmp(&self, cursor_location: &DiffTransforms<MBD>, _: ()) -> cmp::Ordering {
7196        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7197    }
7198}
7199
7200impl<'a, MBD: MultiBufferDimension> sum_tree::Dimension<'a, DiffTransformSummary>
7201    for OutputDimension<MBD>
7202{
7203    fn zero(_: ()) -> Self {
7204        OutputDimension(MBD::default())
7205    }
7206
7207    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7208        self.0.add_mb_text_summary(&summary.output)
7209    }
7210}
7211
7212impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7213    fn zero(_: ()) -> Self {
7214        Point::new(0, 0)
7215    }
7216
7217    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7218        *self += summary.output.lines
7219    }
7220}
7221
7222impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for PointUtf16 {
7223    fn zero(_: ()) -> Self {
7224        PointUtf16::new(0, 0)
7225    }
7226
7227    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: ()) {
7228        *self += summary.output.lines_utf16()
7229    }
7230}
7231
7232impl MultiBufferRows<'_> {
7233    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7234        self.point = Point::new(row, 0);
7235        self.cursor.seek(&self.point);
7236    }
7237}
7238
7239impl Iterator for MultiBufferRows<'_> {
7240    type Item = RowInfo;
7241
7242    fn next(&mut self) -> Option<Self::Item> {
7243        if self.is_empty && self.point.row == 0 {
7244            self.point += Point::new(1, 0);
7245            return Some(RowInfo {
7246                buffer_id: None,
7247                buffer_row: Some(0),
7248                multibuffer_row: Some(MultiBufferRow(0)),
7249                diff_status: None,
7250                expand_info: None,
7251                wrapped_buffer_row: None,
7252            });
7253        }
7254
7255        let mut region = self.cursor.region()?;
7256        while self.point >= region.range.end {
7257            self.cursor.next();
7258            if let Some(next_region) = self.cursor.region() {
7259                region = next_region;
7260            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7261                let multibuffer_row = MultiBufferRow(self.point.row);
7262                let last_excerpt = self
7263                    .cursor
7264                    .excerpts
7265                    .item()
7266                    .or(self.cursor.excerpts.prev_item())?;
7267                let last_row = last_excerpt
7268                    .range
7269                    .context
7270                    .end
7271                    .to_point(&last_excerpt.buffer)
7272                    .row;
7273
7274                let first_row = last_excerpt
7275                    .range
7276                    .context
7277                    .start
7278                    .to_point(&last_excerpt.buffer)
7279                    .row;
7280
7281                let expand_info = if self.is_singleton {
7282                    None
7283                } else {
7284                    let needs_expand_up = first_row == last_row
7285                        && last_row > 0
7286                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7287                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7288
7289                    if needs_expand_up && needs_expand_down {
7290                        Some(ExpandExcerptDirection::UpAndDown)
7291                    } else if needs_expand_up {
7292                        Some(ExpandExcerptDirection::Up)
7293                    } else if needs_expand_down {
7294                        Some(ExpandExcerptDirection::Down)
7295                    } else {
7296                        None
7297                    }
7298                    .map(|direction| ExpandInfo {
7299                        direction,
7300                        excerpt_id: last_excerpt.id,
7301                    })
7302                };
7303                self.point += Point::new(1, 0);
7304                return Some(RowInfo {
7305                    buffer_id: Some(last_excerpt.buffer_id),
7306                    buffer_row: Some(last_row),
7307                    multibuffer_row: Some(multibuffer_row),
7308                    diff_status: None,
7309                    wrapped_buffer_row: None,
7310                    expand_info,
7311                });
7312            } else {
7313                return None;
7314            };
7315        }
7316
7317        let overshoot = self.point - region.range.start;
7318        let buffer_point = region.buffer_range.start + overshoot;
7319        let expand_info = if self.is_singleton {
7320            None
7321        } else {
7322            let needs_expand_up = self.point.row == region.range.start.row
7323                && self.cursor.is_at_start_of_excerpt()
7324                && buffer_point.row > 0;
7325            let needs_expand_down = (region.excerpt.has_trailing_newline
7326                && self.point.row + 1 == region.range.end.row
7327                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7328                && self.cursor.is_at_end_of_excerpt()
7329                && buffer_point.row < region.buffer.max_point().row;
7330
7331            if needs_expand_up && needs_expand_down {
7332                Some(ExpandExcerptDirection::UpAndDown)
7333            } else if needs_expand_up {
7334                Some(ExpandExcerptDirection::Up)
7335            } else if needs_expand_down {
7336                Some(ExpandExcerptDirection::Down)
7337            } else {
7338                None
7339            }
7340            .map(|direction| ExpandInfo {
7341                direction,
7342                excerpt_id: region.excerpt.id,
7343            })
7344        };
7345
7346        let result = Some(RowInfo {
7347            buffer_id: Some(region.buffer.remote_id()),
7348            buffer_row: Some(buffer_point.row),
7349            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7350            diff_status: region
7351                .diff_hunk_status
7352                .filter(|_| self.point < region.range.end),
7353            expand_info,
7354            wrapped_buffer_row: None,
7355        });
7356        self.point += Point::new(1, 0);
7357        result
7358    }
7359}
7360
7361impl<'a> MultiBufferChunks<'a> {
7362    pub fn offset(&self) -> MultiBufferOffset {
7363        self.range.start
7364    }
7365
7366    pub fn seek(&mut self, range: Range<MultiBufferOffset>) {
7367        self.diff_transforms.seek(&range.end, Bias::Right);
7368        let mut excerpt_end = self.diff_transforms.start().1;
7369        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7370            let overshoot = range.end - self.diff_transforms.start().0;
7371            excerpt_end.value += overshoot;
7372        }
7373
7374        self.diff_transforms.seek(&range.start, Bias::Right);
7375        let mut excerpt_start = self.diff_transforms.start().1;
7376        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7377            let overshoot = range.start - self.diff_transforms.start().0;
7378            excerpt_start.value += overshoot;
7379        }
7380
7381        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7382        self.buffer_chunk.take();
7383        self.range = range;
7384    }
7385
7386    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7387        self.excerpt_offset_range = new_range.clone();
7388        self.excerpts.seek(&new_range.start, Bias::Right);
7389        if let Some(excerpt) = self.excerpts.item() {
7390            let excerpt_start = *self.excerpts.start();
7391            if let Some(excerpt_chunks) = self
7392                .excerpt_chunks
7393                .as_mut()
7394                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7395            {
7396                excerpt.seek_chunks(
7397                    excerpt_chunks,
7398                    (self.excerpt_offset_range.start - excerpt_start).value
7399                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7400                );
7401            } else {
7402                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7403                    (self.excerpt_offset_range.start - excerpt_start).value
7404                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7405                    self.language_aware,
7406                ));
7407            }
7408        } else {
7409            self.excerpt_chunks = None;
7410        }
7411    }
7412
7413    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7414        loop {
7415            if self.excerpt_offset_range.is_empty() {
7416                return None;
7417            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7418                self.excerpt_offset_range.start.value += chunk.text.len();
7419                return Some(chunk);
7420            } else {
7421                self.excerpts.next();
7422                let excerpt = self.excerpts.item()?;
7423                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7424                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7425                    self.language_aware,
7426                ));
7427            }
7428        }
7429    }
7430}
7431
7432impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7433    type Item = &'a str;
7434
7435    fn next(&mut self) -> Option<Self::Item> {
7436        let mut region = self.cursor.region()?;
7437        if self.offset == region.range.start {
7438            self.cursor.prev();
7439            region = self.cursor.region()?;
7440            let start_overshoot = self.start.saturating_sub(region.range.start);
7441            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7442                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7443            ));
7444        }
7445
7446        if self.offset == region.range.end && region.has_trailing_newline {
7447            self.offset -= 1;
7448            Some("\n")
7449        } else {
7450            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7451            self.offset -= chunk.len();
7452            Some(chunk)
7453        }
7454    }
7455}
7456
7457impl<'a> Iterator for MultiBufferChunks<'a> {
7458    type Item = Chunk<'a>;
7459
7460    fn next(&mut self) -> Option<Chunk<'a>> {
7461        if self.range.start >= self.range.end {
7462            return None;
7463        }
7464        if self.range.start == self.diff_transforms.end().0 {
7465            self.diff_transforms.next();
7466        }
7467
7468        let diff_transform_start = self.diff_transforms.start().0;
7469        let diff_transform_end = self.diff_transforms.end().0;
7470        debug_assert!(
7471            self.range.start < diff_transform_end,
7472            "{:?} < {:?} of ({1:?}..{2:?})",
7473            self.range.start,
7474            diff_transform_end,
7475            diff_transform_start
7476        );
7477
7478        let diff_transform = self.diff_transforms.item()?;
7479        match diff_transform {
7480            DiffTransform::BufferContent { .. } => {
7481                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7482                    chunk
7483                } else {
7484                    let chunk = self.next_excerpt_chunk().unwrap();
7485                    self.buffer_chunk.insert(chunk)
7486                };
7487
7488                let chunk_end = self.range.start + chunk.text.len();
7489                let diff_transform_end = diff_transform_end.min(self.range.end);
7490
7491                if diff_transform_end < chunk_end {
7492                    let split_idx = diff_transform_end - self.range.start;
7493                    let (before, after) = chunk.text.split_at(split_idx);
7494                    self.range.start = diff_transform_end;
7495                    let mask = 1u128.unbounded_shl(split_idx as u32).wrapping_sub(1);
7496                    let chars = chunk.chars & mask;
7497                    let tabs = chunk.tabs & mask;
7498
7499                    chunk.text = after;
7500                    chunk.chars = chunk.chars >> split_idx;
7501                    chunk.tabs = chunk.tabs >> split_idx;
7502
7503                    Some(Chunk {
7504                        text: before,
7505                        chars,
7506                        tabs,
7507                        ..chunk.clone()
7508                    })
7509                } else {
7510                    self.range.start = chunk_end;
7511                    self.buffer_chunk.take()
7512                }
7513            }
7514            DiffTransform::DeletedHunk {
7515                buffer_id,
7516                base_text_byte_range,
7517                has_trailing_newline,
7518                ..
7519            } => {
7520                let base_text_start =
7521                    base_text_byte_range.start + (self.range.start - diff_transform_start);
7522                let base_text_end =
7523                    base_text_byte_range.start + (self.range.end - diff_transform_start);
7524                let base_text_end = base_text_end.min(base_text_byte_range.end);
7525
7526                let mut chunks = if let Some((_, mut chunks)) = self
7527                    .diff_base_chunks
7528                    .take()
7529                    .filter(|(id, _)| id == buffer_id)
7530                {
7531                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7532                    {
7533                        chunks.seek(base_text_start..base_text_end);
7534                    }
7535                    chunks
7536                } else {
7537                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7538                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7539                };
7540
7541                let chunk = if let Some(chunk) = chunks.next() {
7542                    self.range.start += chunk.text.len();
7543                    self.diff_base_chunks = Some((*buffer_id, chunks));
7544                    chunk
7545                } else {
7546                    debug_assert!(has_trailing_newline);
7547                    self.range.start += "\n".len();
7548                    Chunk {
7549                        text: "\n",
7550                        chars: 1u128,
7551                        ..Default::default()
7552                    }
7553                };
7554                Some(chunk)
7555            }
7556        }
7557    }
7558}
7559
7560impl MultiBufferBytes<'_> {
7561    fn consume(&mut self, len: usize) {
7562        self.range.start += len;
7563        self.chunk = &self.chunk[len..];
7564
7565        if !self.range.is_empty() && self.chunk.is_empty() {
7566            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7567                self.chunk = chunk;
7568            } else if self.has_trailing_newline {
7569                self.has_trailing_newline = false;
7570                self.chunk = b"\n";
7571            } else {
7572                self.cursor.next();
7573                if let Some(region) = self.cursor.region() {
7574                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7575                        region.buffer_range.start
7576                            ..(region.buffer_range.start + (self.range.end - region.range.start))
7577                                .min(region.buffer_range.end),
7578                    );
7579                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7580                    self.excerpt_bytes = Some(excerpt_bytes);
7581                    self.has_trailing_newline =
7582                        region.has_trailing_newline && self.range.end >= region.range.end;
7583                    if self.chunk.is_empty() && self.has_trailing_newline {
7584                        self.has_trailing_newline = false;
7585                        self.chunk = b"\n";
7586                    }
7587                }
7588            }
7589        }
7590    }
7591}
7592
7593impl<'a> Iterator for MultiBufferBytes<'a> {
7594    type Item = &'a [u8];
7595
7596    fn next(&mut self) -> Option<Self::Item> {
7597        let chunk = self.chunk;
7598        if chunk.is_empty() {
7599            None
7600        } else {
7601            self.consume(chunk.len());
7602            Some(chunk)
7603        }
7604    }
7605}
7606
7607impl io::Read for MultiBufferBytes<'_> {
7608    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7609        let len = cmp::min(buf.len(), self.chunk.len());
7610        buf[..len].copy_from_slice(&self.chunk[..len]);
7611        if len > 0 {
7612            self.consume(len);
7613        }
7614        Ok(len)
7615    }
7616}
7617
7618impl io::Read for ReversedMultiBufferBytes<'_> {
7619    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7620        let len = cmp::min(buf.len(), self.chunk.len());
7621        buf[..len].copy_from_slice(&self.chunk[..len]);
7622        buf[..len].reverse();
7623        if len > 0 {
7624            self.range.end -= len;
7625            self.chunk = &self.chunk[..self.chunk.len() - len];
7626            if !self.range.is_empty()
7627                && self.chunk.is_empty()
7628                && let Some(chunk) = self.chunks.next()
7629            {
7630                self.chunk = chunk.as_bytes();
7631            }
7632        }
7633        Ok(len)
7634    }
7635}
7636
7637impl<'a> Iterator for ExcerptChunks<'a> {
7638    type Item = Chunk<'a>;
7639
7640    fn next(&mut self) -> Option<Self::Item> {
7641        if let Some(chunk) = self.content_chunks.next() {
7642            return Some(chunk);
7643        }
7644
7645        if self.has_footer {
7646            let text = "\n";
7647            let chars = 0b1;
7648            self.has_footer = false;
7649            return Some(Chunk {
7650                text,
7651                chars,
7652                ..Default::default()
7653            });
7654        }
7655
7656        None
7657    }
7658}
7659
7660impl ToOffset for Point {
7661    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7662        snapshot.point_to_offset(*self)
7663    }
7664    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7665        snapshot.point_to_offset_utf16(*self)
7666    }
7667}
7668
7669impl ToOffset for MultiBufferOffset {
7670    #[track_caller]
7671    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7672        assert!(
7673            *self <= snapshot.len(),
7674            "offset {} is greater than the snapshot.len() {}",
7675            self.0,
7676            snapshot.len().0,
7677        );
7678        *self
7679    }
7680    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7681        snapshot.offset_to_offset_utf16(*self)
7682    }
7683}
7684
7685impl ToOffset for MultiBufferOffsetUtf16 {
7686    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7687        snapshot.offset_utf16_to_offset(*self)
7688    }
7689
7690    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7691        *self
7692    }
7693}
7694
7695impl ToOffset for PointUtf16 {
7696    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffset {
7697        snapshot.point_utf16_to_offset(*self)
7698    }
7699    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> MultiBufferOffsetUtf16 {
7700        snapshot.point_utf16_to_offset_utf16(*self)
7701    }
7702}
7703
7704impl ToPoint for MultiBufferOffset {
7705    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7706        snapshot.offset_to_point(*self)
7707    }
7708    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7709        snapshot.offset_to_point_utf16(*self)
7710    }
7711}
7712
7713impl ToPoint for Point {
7714    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7715        *self
7716    }
7717    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7718        snapshot.point_to_point_utf16(*self)
7719    }
7720}
7721
7722impl ToPoint for PointUtf16 {
7723    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7724        snapshot.point_utf16_to_point(*self)
7725    }
7726    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7727        *self
7728    }
7729}
7730
7731impl From<ExcerptId> for EntityId {
7732    fn from(id: ExcerptId) -> Self {
7733        EntityId::from(id.0 as u64)
7734    }
7735}
7736
7737#[cfg(debug_assertions)]
7738pub mod debug {
7739    use super::*;
7740
7741    pub trait ToMultiBufferDebugRanges {
7742        fn to_multi_buffer_debug_ranges(
7743            &self,
7744            snapshot: &MultiBufferSnapshot,
7745        ) -> Vec<Range<MultiBufferOffset>>;
7746    }
7747
7748    impl<T: ToOffset> ToMultiBufferDebugRanges for T {
7749        fn to_multi_buffer_debug_ranges(
7750            &self,
7751            snapshot: &MultiBufferSnapshot,
7752        ) -> Vec<Range<MultiBufferOffset>> {
7753            [self.to_offset(snapshot)].to_multi_buffer_debug_ranges(snapshot)
7754        }
7755    }
7756
7757    impl<T: ToOffset> ToMultiBufferDebugRanges for Range<T> {
7758        fn to_multi_buffer_debug_ranges(
7759            &self,
7760            snapshot: &MultiBufferSnapshot,
7761        ) -> Vec<Range<MultiBufferOffset>> {
7762            [self.start.to_offset(snapshot)..self.end.to_offset(snapshot)]
7763                .to_multi_buffer_debug_ranges(snapshot)
7764        }
7765    }
7766
7767    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<T> {
7768        fn to_multi_buffer_debug_ranges(
7769            &self,
7770            snapshot: &MultiBufferSnapshot,
7771        ) -> Vec<Range<MultiBufferOffset>> {
7772            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7773        }
7774    }
7775
7776    impl<T: ToOffset> ToMultiBufferDebugRanges for Vec<Range<T>> {
7777        fn to_multi_buffer_debug_ranges(
7778            &self,
7779            snapshot: &MultiBufferSnapshot,
7780        ) -> Vec<Range<MultiBufferOffset>> {
7781            self.as_slice().to_multi_buffer_debug_ranges(snapshot)
7782        }
7783    }
7784
7785    impl<T: ToOffset> ToMultiBufferDebugRanges for [T] {
7786        fn to_multi_buffer_debug_ranges(
7787            &self,
7788            snapshot: &MultiBufferSnapshot,
7789        ) -> Vec<Range<MultiBufferOffset>> {
7790            self.iter()
7791                .map(|item| {
7792                    let offset = item.to_offset(snapshot);
7793                    offset..offset
7794                })
7795                .collect()
7796        }
7797    }
7798
7799    impl<T: ToOffset> ToMultiBufferDebugRanges for [Range<T>] {
7800        fn to_multi_buffer_debug_ranges(
7801            &self,
7802            snapshot: &MultiBufferSnapshot,
7803        ) -> Vec<Range<MultiBufferOffset>> {
7804            self.iter()
7805                .map(|range| range.start.to_offset(snapshot)..range.end.to_offset(snapshot))
7806                .collect()
7807        }
7808    }
7809}