multi_buffer.rs

   1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{Result, anyhow};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  17use itertools::Itertools;
  18use language::{
  19    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  20    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  21    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  22    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  23    Unclipped,
  24    language_settings::{IndentGuideSettings, LanguageSettings, language_settings},
  25};
  26
  27use rope::DimensionPair;
  28use smallvec::SmallVec;
  29use smol::future::yield_now;
  30use std::{
  31    any::type_name,
  32    borrow::Cow,
  33    cell::{Cell, Ref, RefCell},
  34    cmp, fmt,
  35    future::Future,
  36    io,
  37    iter::{self, FromIterator},
  38    mem,
  39    ops::{Range, RangeBounds, Sub},
  40    path::{Path, PathBuf},
  41    rc::Rc,
  42    str,
  43    sync::Arc,
  44    time::{Duration, Instant},
  45};
  46use sum_tree::{Bias, Cursor, Dimension, Dimensions, SumTree, Summary, TreeMap};
  47use text::{
  48    BufferId, Edit, LineIndent, TextSummary,
  49    locator::Locator,
  50    subscription::{Subscription, Topic},
  51};
  52use theme::SyntaxTheme;
  53use util::post_inc;
  54
  55const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  56
  57#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  58pub struct ExcerptId(usize);
  59
  60/// One or more [`Buffers`](Buffer) being edited in a single view.
  61///
  62/// See <https://zed.dev/features#multi-buffers>
  63pub struct MultiBuffer {
  64    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  65    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  66    snapshot: RefCell<MultiBufferSnapshot>,
  67    /// Contains the state of the buffers being edited
  68    buffers: RefCell<HashMap<BufferId, BufferState>>,
  69    // only used by consumers using `set_excerpts_for_buffer`
  70    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  71    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  72    diffs: HashMap<BufferId, DiffState>,
  73    // all_diff_hunks_expanded: bool,
  74    subscriptions: Topic,
  75    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  76    singleton: bool,
  77    history: History,
  78    title: Option<String>,
  79    capability: Capability,
  80    buffer_changed_since_sync: Rc<Cell<bool>>,
  81}
  82
  83#[derive(Clone, Debug, PartialEq, Eq)]
  84pub enum MultiOrSingleBufferOffsetRange {
  85    Single(Range<usize>),
  86    Multi(Range<usize>),
  87}
  88
  89#[derive(Clone, Debug, PartialEq, Eq)]
  90pub enum Event {
  91    ExcerptsAdded {
  92        buffer: Entity<Buffer>,
  93        predecessor: ExcerptId,
  94        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  95    },
  96    ExcerptsRemoved {
  97        ids: Vec<ExcerptId>,
  98        removed_buffer_ids: Vec<BufferId>,
  99    },
 100    ExcerptsExpanded {
 101        ids: Vec<ExcerptId>,
 102    },
 103    ExcerptsEdited {
 104        excerpt_ids: Vec<ExcerptId>,
 105        buffer_ids: Vec<BufferId>,
 106    },
 107    DiffHunksToggled,
 108    Edited {
 109        singleton_buffer_edited: bool,
 110        edited_buffer: Option<Entity<Buffer>>,
 111    },
 112    TransactionUndone {
 113        transaction_id: TransactionId,
 114    },
 115    Reloaded,
 116    LanguageChanged(BufferId),
 117    Reparsed(BufferId),
 118    Saved,
 119    FileHandleChanged,
 120    DirtyChanged,
 121    DiagnosticsUpdated,
 122    BufferDiffChanged,
 123}
 124
 125/// A diff hunk, representing a range of consequent lines in a multibuffer.
 126#[derive(Debug, Clone, PartialEq, Eq)]
 127pub struct MultiBufferDiffHunk {
 128    /// The row range in the multibuffer where this diff hunk appears.
 129    pub row_range: Range<MultiBufferRow>,
 130    /// The buffer ID that this hunk belongs to.
 131    pub buffer_id: BufferId,
 132    /// The range of the underlying buffer that this hunk corresponds to.
 133    pub buffer_range: Range<text::Anchor>,
 134    /// The excerpt that contains the diff hunk.
 135    pub excerpt_id: ExcerptId,
 136    /// The range within the buffer's diff base that this hunk corresponds to.
 137    pub diff_base_byte_range: Range<usize>,
 138    /// Whether or not this hunk also appears in the 'secondary diff'.
 139    pub secondary_status: DiffHunkSecondaryStatus,
 140}
 141
 142impl MultiBufferDiffHunk {
 143    pub fn status(&self) -> DiffHunkStatus {
 144        let kind = if self.buffer_range.start == self.buffer_range.end {
 145            DiffHunkStatusKind::Deleted
 146        } else if self.diff_base_byte_range.is_empty() {
 147            DiffHunkStatusKind::Added
 148        } else {
 149            DiffHunkStatusKind::Modified
 150        };
 151        DiffHunkStatus {
 152            kind,
 153            secondary: self.secondary_status,
 154        }
 155    }
 156
 157    pub fn is_created_file(&self) -> bool {
 158        self.diff_base_byte_range == (0..0)
 159            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 160    }
 161
 162    pub fn multi_buffer_range(&self) -> Range<Anchor> {
 163        let start = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.start);
 164        let end = Anchor::in_buffer(self.excerpt_id, self.buffer_id, self.buffer_range.end);
 165        start..end
 166    }
 167}
 168
 169#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 170pub struct PathKey {
 171    namespace: u32,
 172    path: Arc<Path>,
 173}
 174
 175impl PathKey {
 176    pub fn namespaced(namespace: u32, path: Arc<Path>) -> Self {
 177        Self { namespace, path }
 178    }
 179
 180    pub fn for_buffer(buffer: &Entity<Buffer>, cx: &App) -> Self {
 181        if let Some(file) = buffer.read(cx).file() {
 182            Self::namespaced(1, Arc::from(file.full_path(cx)))
 183        } else {
 184            Self::namespaced(0, Arc::from(PathBuf::from(buffer.entity_id().to_string())))
 185        }
 186    }
 187
 188    pub fn path(&self) -> &Arc<Path> {
 189        &self.path
 190    }
 191}
 192
 193pub type MultiBufferPoint = Point;
 194type ExcerptOffset = TypedOffset<Excerpt>;
 195type ExcerptPoint = TypedPoint<Excerpt>;
 196
 197#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 198#[serde(transparent)]
 199pub struct MultiBufferRow(pub u32);
 200
 201impl MultiBufferRow {
 202    pub const MIN: Self = Self(0);
 203    pub const MAX: Self = Self(u32::MAX);
 204}
 205
 206impl std::ops::Add<usize> for MultiBufferRow {
 207    type Output = Self;
 208
 209    fn add(self, rhs: usize) -> Self::Output {
 210        MultiBufferRow(self.0 + rhs as u32)
 211    }
 212}
 213
 214#[derive(Clone)]
 215struct History {
 216    next_transaction_id: TransactionId,
 217    undo_stack: Vec<Transaction>,
 218    redo_stack: Vec<Transaction>,
 219    transaction_depth: usize,
 220    group_interval: Duration,
 221}
 222
 223#[derive(Clone)]
 224struct Transaction {
 225    id: TransactionId,
 226    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 227    first_edit_at: Instant,
 228    last_edit_at: Instant,
 229    suppress_grouping: bool,
 230}
 231
 232pub trait ToOffset: 'static + fmt::Debug {
 233    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 234}
 235
 236pub trait ToOffsetUtf16: 'static + fmt::Debug {
 237    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 238}
 239
 240pub trait ToPoint: 'static + fmt::Debug {
 241    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 242}
 243
 244pub trait ToPointUtf16: 'static + fmt::Debug {
 245    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 246}
 247
 248struct BufferState {
 249    buffer: Entity<Buffer>,
 250    last_version: clock::Global,
 251    last_non_text_state_update_count: usize,
 252    excerpts: Vec<Locator>,
 253    _subscriptions: [gpui::Subscription; 2],
 254}
 255
 256struct DiffState {
 257    diff: Entity<BufferDiff>,
 258    _subscription: gpui::Subscription,
 259}
 260
 261impl DiffState {
 262    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 263        DiffState {
 264            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 265                BufferDiffEvent::DiffChanged { changed_range } => {
 266                    if let Some(changed_range) = changed_range.clone() {
 267                        this.buffer_diff_changed(diff, changed_range, cx)
 268                    }
 269                    cx.emit(Event::BufferDiffChanged);
 270                }
 271                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 272                _ => {}
 273            }),
 274            diff,
 275        }
 276    }
 277}
 278
 279/// The contents of a [`MultiBuffer`] at a single point in time.
 280#[derive(Clone, Default)]
 281pub struct MultiBufferSnapshot {
 282    singleton: bool,
 283    excerpts: SumTree<Excerpt>,
 284    excerpt_ids: SumTree<ExcerptIdMapping>,
 285    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 286    diff_transforms: SumTree<DiffTransform>,
 287    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 288    trailing_excerpt_update_count: usize,
 289    all_diff_hunks_expanded: bool,
 290    non_text_state_update_count: usize,
 291    edit_count: usize,
 292    is_dirty: bool,
 293    has_deleted_file: bool,
 294    has_conflict: bool,
 295    show_headers: bool,
 296}
 297
 298#[derive(Debug, Clone)]
 299enum DiffTransform {
 300    BufferContent {
 301        summary: TextSummary,
 302        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 303    },
 304    DeletedHunk {
 305        summary: TextSummary,
 306        buffer_id: BufferId,
 307        hunk_info: DiffTransformHunkInfo,
 308        base_text_byte_range: Range<usize>,
 309        has_trailing_newline: bool,
 310    },
 311}
 312
 313#[derive(Clone, Copy, Debug)]
 314struct DiffTransformHunkInfo {
 315    excerpt_id: ExcerptId,
 316    hunk_start_anchor: text::Anchor,
 317    hunk_secondary_status: DiffHunkSecondaryStatus,
 318}
 319
 320impl Eq for DiffTransformHunkInfo {}
 321
 322impl PartialEq for DiffTransformHunkInfo {
 323    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 324        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 325    }
 326}
 327
 328impl std::hash::Hash for DiffTransformHunkInfo {
 329    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 330        self.excerpt_id.hash(state);
 331        self.hunk_start_anchor.hash(state);
 332    }
 333}
 334
 335#[derive(Clone)]
 336pub struct ExcerptInfo {
 337    pub id: ExcerptId,
 338    pub buffer: BufferSnapshot,
 339    pub buffer_id: BufferId,
 340    pub range: ExcerptRange<text::Anchor>,
 341    pub end_row: MultiBufferRow,
 342}
 343
 344impl std::fmt::Debug for ExcerptInfo {
 345    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 346        f.debug_struct(type_name::<Self>())
 347            .field("id", &self.id)
 348            .field("buffer_id", &self.buffer_id)
 349            .field("path", &self.buffer.file().map(|f| f.path()))
 350            .field("range", &self.range)
 351            .finish()
 352    }
 353}
 354
 355/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 356#[derive(Debug)]
 357pub struct ExcerptBoundary {
 358    pub prev: Option<ExcerptInfo>,
 359    pub next: ExcerptInfo,
 360    /// The row in the `MultiBuffer` where the boundary is located
 361    pub row: MultiBufferRow,
 362}
 363
 364impl ExcerptBoundary {
 365    pub fn starts_new_buffer(&self) -> bool {
 366        match (self.prev.as_ref(), &self.next) {
 367            (None, _) => true,
 368            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 369        }
 370    }
 371}
 372
 373#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 374pub struct ExpandInfo {
 375    pub direction: ExpandExcerptDirection,
 376    pub excerpt_id: ExcerptId,
 377}
 378
 379#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 380pub struct RowInfo {
 381    pub buffer_id: Option<BufferId>,
 382    pub buffer_row: Option<u32>,
 383    pub multibuffer_row: Option<MultiBufferRow>,
 384    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 385    pub expand_info: Option<ExpandInfo>,
 386}
 387
 388/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 389#[derive(Clone)]
 390struct Excerpt {
 391    /// The unique identifier for this excerpt
 392    id: ExcerptId,
 393    /// The location of the excerpt in the [`MultiBuffer`]
 394    locator: Locator,
 395    /// The buffer being excerpted
 396    buffer_id: BufferId,
 397    /// A snapshot of the buffer being excerpted
 398    buffer: BufferSnapshot,
 399    /// The range of the buffer to be shown in the excerpt
 400    range: ExcerptRange<text::Anchor>,
 401    /// The last row in the excerpted slice of the buffer
 402    max_buffer_row: BufferRow,
 403    /// A summary of the text in the excerpt
 404    text_summary: TextSummary,
 405    has_trailing_newline: bool,
 406}
 407
 408/// A public view into an `Excerpt` in a [`MultiBuffer`].
 409///
 410/// Contains methods for getting the [`Buffer`] of the excerpt,
 411/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 412#[derive(Clone)]
 413pub struct MultiBufferExcerpt<'a> {
 414    excerpt: &'a Excerpt,
 415    diff_transforms: sum_tree::Cursor<'a, DiffTransform, DiffTransforms<usize>>,
 416    offset: usize,
 417    excerpt_offset: ExcerptDimension<usize>,
 418    buffer_offset: usize,
 419}
 420
 421#[derive(Clone, Debug)]
 422struct ExcerptIdMapping {
 423    id: ExcerptId,
 424    locator: Locator,
 425}
 426
 427/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 428/// These ranges are relative to the buffer itself
 429#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 430pub struct ExcerptRange<T> {
 431    /// The full range of text to be shown in the excerpt.
 432    pub context: Range<T>,
 433    /// The primary range of text to be highlighted in the excerpt.
 434    /// In a multi-buffer search, this would be the text that matched the search
 435    pub primary: Range<T>,
 436}
 437
 438impl<T: Clone> ExcerptRange<T> {
 439    pub fn new(context: Range<T>) -> Self {
 440        Self {
 441            context: context.clone(),
 442            primary: context,
 443        }
 444    }
 445}
 446
 447#[derive(Clone, Debug, Default)]
 448pub struct ExcerptSummary {
 449    excerpt_id: ExcerptId,
 450    /// The location of the last [`Excerpt`] being summarized
 451    excerpt_locator: Locator,
 452    widest_line_number: u32,
 453    text: TextSummary,
 454}
 455
 456#[derive(Debug, Clone)]
 457pub struct DiffTransformSummary {
 458    input: TextSummary,
 459    output: TextSummary,
 460}
 461
 462#[derive(Clone)]
 463pub struct MultiBufferRows<'a> {
 464    point: Point,
 465    is_empty: bool,
 466    is_singleton: bool,
 467    cursor: MultiBufferCursor<'a, Point>,
 468}
 469
 470pub struct MultiBufferChunks<'a> {
 471    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 472    diff_transforms: Cursor<'a, DiffTransform, Dimensions<usize, ExcerptOffset>>,
 473    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 474    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 475    buffer_chunk: Option<Chunk<'a>>,
 476    range: Range<usize>,
 477    excerpt_offset_range: Range<ExcerptOffset>,
 478    excerpt_chunks: Option<ExcerptChunks<'a>>,
 479    language_aware: bool,
 480}
 481
 482pub struct ReversedMultiBufferChunks<'a> {
 483    cursor: MultiBufferCursor<'a, usize>,
 484    current_chunks: Option<rope::Chunks<'a>>,
 485    start: usize,
 486    offset: usize,
 487}
 488
 489pub struct MultiBufferBytes<'a> {
 490    range: Range<usize>,
 491    cursor: MultiBufferCursor<'a, usize>,
 492    excerpt_bytes: Option<text::Bytes<'a>>,
 493    has_trailing_newline: bool,
 494    chunk: &'a [u8],
 495}
 496
 497pub struct ReversedMultiBufferBytes<'a> {
 498    range: Range<usize>,
 499    chunks: ReversedMultiBufferChunks<'a>,
 500    chunk: &'a [u8],
 501}
 502
 503#[derive(Clone)]
 504struct DiffTransforms<D> {
 505    output_dimension: OutputDimension<D>,
 506    excerpt_dimension: ExcerptDimension<D>,
 507}
 508
 509impl<'a, D: TextDimension> Dimension<'a, DiffTransformSummary> for DiffTransforms<D> {
 510    fn zero(cx: &<DiffTransformSummary as sum_tree::Summary>::Context) -> Self {
 511        Self {
 512            output_dimension: OutputDimension::zero(cx),
 513            excerpt_dimension: <ExcerptDimension<D> as Dimension<'a, DiffTransformSummary>>::zero(
 514                cx,
 515            ),
 516        }
 517    }
 518
 519    fn add_summary(
 520        &mut self,
 521        summary: &'a DiffTransformSummary,
 522        cx: &<DiffTransformSummary as sum_tree::Summary>::Context,
 523    ) {
 524        self.output_dimension.add_summary(summary, cx);
 525        self.excerpt_dimension.add_summary(summary, cx);
 526    }
 527}
 528
 529#[derive(Clone)]
 530struct MultiBufferCursor<'a, D: TextDimension> {
 531    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 532    diff_transforms: Cursor<'a, DiffTransform, DiffTransforms<D>>,
 533    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 534    cached_region: Option<MultiBufferRegion<'a, D>>,
 535}
 536
 537#[derive(Clone)]
 538struct MultiBufferRegion<'a, D: TextDimension> {
 539    buffer: &'a BufferSnapshot,
 540    is_main_buffer: bool,
 541    diff_hunk_status: Option<DiffHunkStatus>,
 542    excerpt: &'a Excerpt,
 543    buffer_range: Range<D>,
 544    range: Range<D>,
 545    has_trailing_newline: bool,
 546}
 547
 548struct ExcerptChunks<'a> {
 549    excerpt_id: ExcerptId,
 550    content_chunks: BufferChunks<'a>,
 551    footer_height: usize,
 552}
 553
 554#[derive(Debug)]
 555struct BufferEdit {
 556    range: Range<usize>,
 557    new_text: Arc<str>,
 558    is_insertion: bool,
 559    original_indent_column: Option<u32>,
 560    excerpt_id: ExcerptId,
 561}
 562
 563#[derive(Clone, Copy, Debug, PartialEq)]
 564enum DiffChangeKind {
 565    BufferEdited,
 566    DiffUpdated { base_changed: bool },
 567    ExpandOrCollapseHunks { expand: bool },
 568}
 569
 570#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 571pub enum ExpandExcerptDirection {
 572    Up,
 573    Down,
 574    UpAndDown,
 575}
 576
 577impl ExpandExcerptDirection {
 578    pub fn should_expand_up(&self) -> bool {
 579        match self {
 580            ExpandExcerptDirection::Up => true,
 581            ExpandExcerptDirection::Down => false,
 582            ExpandExcerptDirection::UpAndDown => true,
 583        }
 584    }
 585
 586    pub fn should_expand_down(&self) -> bool {
 587        match self {
 588            ExpandExcerptDirection::Up => false,
 589            ExpandExcerptDirection::Down => true,
 590            ExpandExcerptDirection::UpAndDown => true,
 591        }
 592    }
 593}
 594
 595#[derive(Clone, Debug, PartialEq)]
 596pub struct IndentGuide {
 597    pub buffer_id: BufferId,
 598    pub start_row: MultiBufferRow,
 599    pub end_row: MultiBufferRow,
 600    pub depth: u32,
 601    pub tab_size: u32,
 602    pub settings: IndentGuideSettings,
 603}
 604
 605impl IndentGuide {
 606    pub fn indent_level(&self) -> u32 {
 607        self.depth * self.tab_size
 608    }
 609}
 610
 611impl MultiBuffer {
 612    pub fn new(capability: Capability) -> Self {
 613        Self {
 614            snapshot: RefCell::new(MultiBufferSnapshot {
 615                show_headers: true,
 616                ..MultiBufferSnapshot::default()
 617            }),
 618            buffers: RefCell::default(),
 619            diffs: HashMap::default(),
 620            subscriptions: Topic::default(),
 621            singleton: false,
 622            capability,
 623            title: None,
 624            excerpts_by_path: Default::default(),
 625            paths_by_excerpt: Default::default(),
 626            buffer_changed_since_sync: Default::default(),
 627            history: History {
 628                next_transaction_id: clock::Lamport::default(),
 629                undo_stack: Vec::new(),
 630                redo_stack: Vec::new(),
 631                transaction_depth: 0,
 632                group_interval: Duration::from_millis(300),
 633            },
 634        }
 635    }
 636
 637    pub fn without_headers(capability: Capability) -> Self {
 638        Self {
 639            snapshot: Default::default(),
 640            buffers: Default::default(),
 641            excerpts_by_path: Default::default(),
 642            paths_by_excerpt: Default::default(),
 643            diffs: HashMap::default(),
 644            subscriptions: Default::default(),
 645            singleton: false,
 646            capability,
 647            buffer_changed_since_sync: Default::default(),
 648            history: History {
 649                next_transaction_id: Default::default(),
 650                undo_stack: Default::default(),
 651                redo_stack: Default::default(),
 652                transaction_depth: 0,
 653                group_interval: Duration::from_millis(300),
 654            },
 655            title: Default::default(),
 656        }
 657    }
 658
 659    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 660        let mut buffers = HashMap::default();
 661        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 662        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 663            buffer_state.buffer.update(new_cx, |buffer, _| {
 664                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 665            });
 666            buffers.insert(
 667                *buffer_id,
 668                BufferState {
 669                    buffer: buffer_state.buffer.clone(),
 670                    last_version: buffer_state.last_version.clone(),
 671                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 672                    excerpts: buffer_state.excerpts.clone(),
 673                    _subscriptions: [
 674                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 675                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 676                    ],
 677                },
 678            );
 679        }
 680        let mut diff_bases = HashMap::default();
 681        for (buffer_id, diff) in self.diffs.iter() {
 682            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 683        }
 684        Self {
 685            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 686            buffers: RefCell::new(buffers),
 687            excerpts_by_path: Default::default(),
 688            paths_by_excerpt: Default::default(),
 689            diffs: diff_bases,
 690            subscriptions: Default::default(),
 691            singleton: self.singleton,
 692            capability: self.capability,
 693            history: self.history.clone(),
 694            title: self.title.clone(),
 695            buffer_changed_since_sync,
 696        }
 697    }
 698
 699    pub fn with_title(mut self, title: String) -> Self {
 700        self.title = Some(title);
 701        self
 702    }
 703
 704    pub fn read_only(&self) -> bool {
 705        self.capability == Capability::ReadOnly
 706    }
 707
 708    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 709        let mut this = Self::new(buffer.read(cx).capability());
 710        this.singleton = true;
 711        this.push_excerpts(
 712            buffer,
 713            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 714            cx,
 715        );
 716        this.snapshot.borrow_mut().singleton = true;
 717        this
 718    }
 719
 720    /// Returns an up-to-date snapshot of the MultiBuffer.
 721    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 722        self.sync(cx);
 723        self.snapshot.borrow().clone()
 724    }
 725
 726    pub fn read(&self, cx: &App) -> Ref<'_, MultiBufferSnapshot> {
 727        self.sync(cx);
 728        self.snapshot.borrow()
 729    }
 730
 731    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 732        if self.singleton {
 733            Some(
 734                self.buffers
 735                    .borrow()
 736                    .values()
 737                    .next()
 738                    .unwrap()
 739                    .buffer
 740                    .clone(),
 741            )
 742        } else {
 743            None
 744        }
 745    }
 746
 747    pub fn is_singleton(&self) -> bool {
 748        self.singleton
 749    }
 750
 751    pub fn subscribe(&mut self) -> Subscription {
 752        self.subscriptions.subscribe()
 753    }
 754
 755    pub fn is_dirty(&self, cx: &App) -> bool {
 756        self.read(cx).is_dirty()
 757    }
 758
 759    pub fn has_deleted_file(&self, cx: &App) -> bool {
 760        self.read(cx).has_deleted_file()
 761    }
 762
 763    pub fn has_conflict(&self, cx: &App) -> bool {
 764        self.read(cx).has_conflict()
 765    }
 766
 767    // The `is_empty` signature doesn't match what clippy expects
 768    #[allow(clippy::len_without_is_empty)]
 769    pub fn len(&self, cx: &App) -> usize {
 770        self.read(cx).len()
 771    }
 772
 773    pub fn is_empty(&self) -> bool {
 774        self.buffers.borrow().is_empty()
 775    }
 776
 777    pub fn symbols_containing<T: ToOffset>(
 778        &self,
 779        offset: T,
 780        theme: Option<&SyntaxTheme>,
 781        cx: &App,
 782    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 783        self.read(cx).symbols_containing(offset, theme)
 784    }
 785
 786    pub fn edit<I, S, T>(
 787        &self,
 788        edits: I,
 789        autoindent_mode: Option<AutoindentMode>,
 790        cx: &mut Context<Self>,
 791    ) where
 792        I: IntoIterator<Item = (Range<S>, T)>,
 793        S: ToOffset,
 794        T: Into<Arc<str>>,
 795    {
 796        let snapshot = self.read(cx);
 797        let edits = edits
 798            .into_iter()
 799            .map(|(range, new_text)| {
 800                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 801                if range.start > range.end {
 802                    mem::swap(&mut range.start, &mut range.end);
 803                }
 804                (range, new_text.into())
 805            })
 806            .collect::<Vec<_>>();
 807
 808        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 809
 810        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 811        fn edit_internal(
 812            this: &MultiBuffer,
 813            snapshot: Ref<MultiBufferSnapshot>,
 814            edits: Vec<(Range<usize>, Arc<str>)>,
 815            mut autoindent_mode: Option<AutoindentMode>,
 816            cx: &mut Context<MultiBuffer>,
 817        ) {
 818            if this.read_only() || this.buffers.borrow().is_empty() {
 819                return;
 820            }
 821
 822            let original_indent_columns = match &mut autoindent_mode {
 823                Some(AutoindentMode::Block {
 824                    original_indent_columns,
 825                }) => mem::take(original_indent_columns),
 826                _ => Default::default(),
 827            };
 828
 829            let (buffer_edits, edited_excerpt_ids) =
 830                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 831            drop(snapshot);
 832
 833            let mut buffer_ids = Vec::with_capacity(buffer_edits.len());
 834            for (buffer_id, mut edits) in buffer_edits {
 835                buffer_ids.push(buffer_id);
 836                edits.sort_by_key(|edit| edit.range.start);
 837                this.buffers.borrow()[&buffer_id]
 838                    .buffer
 839                    .update(cx, |buffer, cx| {
 840                        let mut edits = edits.into_iter().peekable();
 841                        let mut insertions = Vec::new();
 842                        let mut original_indent_columns = Vec::new();
 843                        let mut deletions = Vec::new();
 844                        let empty_str: Arc<str> = Arc::default();
 845                        while let Some(BufferEdit {
 846                            mut range,
 847                            mut new_text,
 848                            mut is_insertion,
 849                            original_indent_column,
 850                            excerpt_id,
 851                        }) = edits.next()
 852                        {
 853                            while let Some(BufferEdit {
 854                                range: next_range,
 855                                is_insertion: next_is_insertion,
 856                                new_text: next_new_text,
 857                                excerpt_id: next_excerpt_id,
 858                                ..
 859                            }) = edits.peek()
 860                            {
 861                                if range.end >= next_range.start {
 862                                    range.end = cmp::max(next_range.end, range.end);
 863                                    is_insertion |= *next_is_insertion;
 864                                    if excerpt_id == *next_excerpt_id {
 865                                        new_text = format!("{new_text}{next_new_text}").into();
 866                                    }
 867                                    edits.next();
 868                                } else {
 869                                    break;
 870                                }
 871                            }
 872
 873                            if is_insertion {
 874                                original_indent_columns.push(original_indent_column);
 875                                insertions.push((
 876                                    buffer.anchor_before(range.start)
 877                                        ..buffer.anchor_before(range.end),
 878                                    new_text.clone(),
 879                                ));
 880                            } else if !range.is_empty() {
 881                                deletions.push((
 882                                    buffer.anchor_before(range.start)
 883                                        ..buffer.anchor_before(range.end),
 884                                    empty_str.clone(),
 885                                ));
 886                            }
 887                        }
 888
 889                        let deletion_autoindent_mode =
 890                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 891                                Some(AutoindentMode::Block {
 892                                    original_indent_columns: Default::default(),
 893                                })
 894                            } else {
 895                                autoindent_mode.clone()
 896                            };
 897                        let insertion_autoindent_mode =
 898                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 899                                Some(AutoindentMode::Block {
 900                                    original_indent_columns,
 901                                })
 902                            } else {
 903                                autoindent_mode.clone()
 904                            };
 905
 906                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 907                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 908                    })
 909            }
 910
 911            cx.emit(Event::ExcerptsEdited {
 912                excerpt_ids: edited_excerpt_ids,
 913                buffer_ids,
 914            });
 915        }
 916    }
 917
 918    fn convert_edits_to_buffer_edits(
 919        &self,
 920        edits: Vec<(Range<usize>, Arc<str>)>,
 921        snapshot: &MultiBufferSnapshot,
 922        original_indent_columns: &[Option<u32>],
 923    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 924        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 925        let mut edited_excerpt_ids = Vec::new();
 926        let mut cursor = snapshot.cursor::<usize>();
 927        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 928            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 929
 930            cursor.seek(&range.start);
 931            let mut start_region = cursor.region().expect("start offset out of bounds");
 932            if !start_region.is_main_buffer {
 933                cursor.next();
 934                if let Some(region) = cursor.region() {
 935                    start_region = region;
 936                } else {
 937                    continue;
 938                }
 939            }
 940
 941            if range.end < start_region.range.start {
 942                continue;
 943            }
 944
 945            if range.end > start_region.range.end {
 946                cursor.seek_forward(&range.end);
 947            }
 948            let mut end_region = cursor.region().expect("end offset out of bounds");
 949            if !end_region.is_main_buffer {
 950                cursor.prev();
 951                if let Some(region) = cursor.region() {
 952                    end_region = region;
 953                } else {
 954                    continue;
 955                }
 956            }
 957
 958            if range.start > end_region.range.end {
 959                continue;
 960            }
 961
 962            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 963            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 964            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 965                .min(start_region.buffer_range.end);
 966            let buffer_end =
 967                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 968
 969            if start_region.excerpt.id == end_region.excerpt.id {
 970                if start_region.is_main_buffer {
 971                    edited_excerpt_ids.push(start_region.excerpt.id);
 972                    buffer_edits
 973                        .entry(start_region.buffer.remote_id())
 974                        .or_default()
 975                        .push(BufferEdit {
 976                            range: buffer_start..buffer_end,
 977                            new_text,
 978                            is_insertion: true,
 979                            original_indent_column,
 980                            excerpt_id: start_region.excerpt.id,
 981                        });
 982                }
 983            } else {
 984                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 985                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 986                if start_region.is_main_buffer {
 987                    edited_excerpt_ids.push(start_region.excerpt.id);
 988                    buffer_edits
 989                        .entry(start_region.buffer.remote_id())
 990                        .or_default()
 991                        .push(BufferEdit {
 992                            range: start_excerpt_range,
 993                            new_text: new_text.clone(),
 994                            is_insertion: true,
 995                            original_indent_column,
 996                            excerpt_id: start_region.excerpt.id,
 997                        });
 998                }
 999                if end_region.is_main_buffer {
1000                    edited_excerpt_ids.push(end_region.excerpt.id);
1001                    buffer_edits
1002                        .entry(end_region.buffer.remote_id())
1003                        .or_default()
1004                        .push(BufferEdit {
1005                            range: end_excerpt_range,
1006                            new_text: new_text.clone(),
1007                            is_insertion: false,
1008                            original_indent_column,
1009                            excerpt_id: end_region.excerpt.id,
1010                        });
1011                }
1012
1013                cursor.seek(&range.start);
1014                cursor.next_excerpt();
1015                while let Some(region) = cursor.region() {
1016                    if region.excerpt.id == end_region.excerpt.id {
1017                        break;
1018                    }
1019                    if region.is_main_buffer {
1020                        edited_excerpt_ids.push(region.excerpt.id);
1021                        buffer_edits
1022                            .entry(region.buffer.remote_id())
1023                            .or_default()
1024                            .push(BufferEdit {
1025                                range: region.buffer_range,
1026                                new_text: new_text.clone(),
1027                                is_insertion: false,
1028                                original_indent_column,
1029                                excerpt_id: region.excerpt.id,
1030                            });
1031                    }
1032                    cursor.next_excerpt();
1033                }
1034            }
1035        }
1036        (buffer_edits, edited_excerpt_ids)
1037    }
1038
1039    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1040    where
1041        I: IntoIterator<Item = Range<S>>,
1042        S: ToOffset,
1043    {
1044        let snapshot = self.read(cx);
1045        let empty = Arc::<str>::from("");
1046        let edits = ranges
1047            .into_iter()
1048            .map(|range| {
1049                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1050                if range.start > range.end {
1051                    mem::swap(&mut range.start, &mut range.end);
1052                }
1053                (range, empty.clone())
1054            })
1055            .collect::<Vec<_>>();
1056
1057        return autoindent_ranges_internal(self, snapshot, edits, cx);
1058
1059        fn autoindent_ranges_internal(
1060            this: &MultiBuffer,
1061            snapshot: Ref<MultiBufferSnapshot>,
1062            edits: Vec<(Range<usize>, Arc<str>)>,
1063            cx: &mut Context<MultiBuffer>,
1064        ) {
1065            if this.read_only() || this.buffers.borrow().is_empty() {
1066                return;
1067            }
1068
1069            let (buffer_edits, edited_excerpt_ids) =
1070                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1071            drop(snapshot);
1072
1073            let mut buffer_ids = Vec::new();
1074            for (buffer_id, mut edits) in buffer_edits {
1075                buffer_ids.push(buffer_id);
1076                edits.sort_unstable_by_key(|edit| edit.range.start);
1077
1078                let mut ranges: Vec<Range<usize>> = Vec::new();
1079                for edit in edits {
1080                    if let Some(last_range) = ranges.last_mut()
1081                        && edit.range.start <= last_range.end
1082                    {
1083                        last_range.end = last_range.end.max(edit.range.end);
1084                        continue;
1085                    }
1086                    ranges.push(edit.range);
1087                }
1088
1089                this.buffers.borrow()[&buffer_id]
1090                    .buffer
1091                    .update(cx, |buffer, cx| {
1092                        buffer.autoindent_ranges(ranges, cx);
1093                    })
1094            }
1095
1096            cx.emit(Event::ExcerptsEdited {
1097                excerpt_ids: edited_excerpt_ids,
1098                buffer_ids,
1099            });
1100        }
1101    }
1102
1103    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1104    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1105    // Panics if the given position is invalid.
1106    pub fn insert_empty_line(
1107        &mut self,
1108        position: impl ToPoint,
1109        space_above: bool,
1110        space_below: bool,
1111        cx: &mut Context<Self>,
1112    ) -> Point {
1113        let multibuffer_point = position.to_point(&self.read(cx));
1114        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1115        self.start_transaction(cx);
1116        let empty_line_start = buffer.update(cx, |buffer, cx| {
1117            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1118        });
1119        self.end_transaction(cx);
1120        multibuffer_point + (empty_line_start - buffer_point)
1121    }
1122
1123    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1124        self.start_transaction_at(Instant::now(), cx)
1125    }
1126
1127    pub fn start_transaction_at(
1128        &mut self,
1129        now: Instant,
1130        cx: &mut Context<Self>,
1131    ) -> Option<TransactionId> {
1132        if let Some(buffer) = self.as_singleton() {
1133            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1134        }
1135
1136        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1137            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1138        }
1139        self.history.start_transaction(now)
1140    }
1141
1142    pub fn last_transaction_id(&self, cx: &App) -> Option<TransactionId> {
1143        if let Some(buffer) = self.as_singleton() {
1144            buffer
1145                .read(cx)
1146                .peek_undo_stack()
1147                .map(|history_entry| history_entry.transaction_id())
1148        } else {
1149            let last_transaction = self.history.undo_stack.last()?;
1150            Some(last_transaction.id)
1151        }
1152    }
1153
1154    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1155        self.end_transaction_at(Instant::now(), cx)
1156    }
1157
1158    pub fn end_transaction_at(
1159        &mut self,
1160        now: Instant,
1161        cx: &mut Context<Self>,
1162    ) -> Option<TransactionId> {
1163        if let Some(buffer) = self.as_singleton() {
1164            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1165        }
1166
1167        let mut buffer_transactions = HashMap::default();
1168        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1169            if let Some(transaction_id) =
1170                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1171            {
1172                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1173            }
1174        }
1175
1176        if self.history.end_transaction(now, buffer_transactions) {
1177            let transaction_id = self.history.group().unwrap();
1178            Some(transaction_id)
1179        } else {
1180            None
1181        }
1182    }
1183
1184    pub fn edited_ranges_for_transaction<D>(
1185        &self,
1186        transaction_id: TransactionId,
1187        cx: &App,
1188    ) -> Vec<Range<D>>
1189    where
1190        D: TextDimension + Ord + Sub<D, Output = D>,
1191    {
1192        let Some(transaction) = self.history.transaction(transaction_id) else {
1193            return Vec::new();
1194        };
1195
1196        let mut ranges = Vec::new();
1197        let snapshot = self.read(cx);
1198        let buffers = self.buffers.borrow();
1199        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1200
1201        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1202            let Some(buffer_state) = buffers.get(buffer_id) else {
1203                continue;
1204            };
1205
1206            let buffer = buffer_state.buffer.read(cx);
1207            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1208                for excerpt_id in &buffer_state.excerpts {
1209                    cursor.seek(excerpt_id, Bias::Left);
1210                    if let Some(excerpt) = cursor.item()
1211                        && excerpt.locator == *excerpt_id
1212                    {
1213                        let excerpt_buffer_start = excerpt.range.context.start.summary::<D>(buffer);
1214                        let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1215                        let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1216                        if excerpt_range.contains(&range.start)
1217                            && excerpt_range.contains(&range.end)
1218                        {
1219                            let excerpt_start = D::from_text_summary(&cursor.start().text);
1220
1221                            let mut start = excerpt_start;
1222                            start.add_assign(&(range.start - excerpt_buffer_start));
1223                            let mut end = excerpt_start;
1224                            end.add_assign(&(range.end - excerpt_buffer_start));
1225
1226                            ranges.push(start..end);
1227                            break;
1228                        }
1229                    }
1230                }
1231            }
1232        }
1233
1234        ranges.sort_by_key(|range| range.start);
1235        ranges
1236    }
1237
1238    pub fn merge_transactions(
1239        &mut self,
1240        transaction: TransactionId,
1241        destination: TransactionId,
1242        cx: &mut Context<Self>,
1243    ) {
1244        if let Some(buffer) = self.as_singleton() {
1245            buffer.update(cx, |buffer, _| {
1246                buffer.merge_transactions(transaction, destination)
1247            });
1248        } else if let Some(transaction) = self.history.forget(transaction)
1249            && let Some(destination) = self.history.transaction_mut(destination)
1250        {
1251            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1252                if let Some(destination_buffer_transaction_id) =
1253                    destination.buffer_transactions.get(&buffer_id)
1254                {
1255                    if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1256                        state.buffer.update(cx, |buffer, _| {
1257                            buffer.merge_transactions(
1258                                buffer_transaction_id,
1259                                *destination_buffer_transaction_id,
1260                            )
1261                        });
1262                    }
1263                } else {
1264                    destination
1265                        .buffer_transactions
1266                        .insert(buffer_id, buffer_transaction_id);
1267                }
1268            }
1269        }
1270    }
1271
1272    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1273        self.history.finalize_last_transaction();
1274        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1275            buffer.update(cx, |buffer, _| {
1276                buffer.finalize_last_transaction();
1277            });
1278        }
1279    }
1280
1281    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1282    where
1283        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1284    {
1285        self.history
1286            .push_transaction(buffer_transactions, Instant::now(), cx);
1287        self.history.finalize_last_transaction();
1288    }
1289
1290    pub fn group_until_transaction(
1291        &mut self,
1292        transaction_id: TransactionId,
1293        cx: &mut Context<Self>,
1294    ) {
1295        if let Some(buffer) = self.as_singleton() {
1296            buffer.update(cx, |buffer, _| {
1297                buffer.group_until_transaction(transaction_id)
1298            });
1299        } else {
1300            self.history.group_until(transaction_id);
1301        }
1302    }
1303
1304    pub fn set_active_selections(
1305        &self,
1306        selections: &[Selection<Anchor>],
1307        line_mode: bool,
1308        cursor_shape: CursorShape,
1309        cx: &mut Context<Self>,
1310    ) {
1311        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1312            Default::default();
1313        let snapshot = self.read(cx);
1314        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1315        for selection in selections {
1316            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1317            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1318
1319            cursor.seek(&Some(start_locator), Bias::Left);
1320            while let Some(excerpt) = cursor.item() {
1321                if excerpt.locator > *end_locator {
1322                    break;
1323                }
1324
1325                let mut start = excerpt.range.context.start;
1326                let mut end = excerpt.range.context.end;
1327                if excerpt.id == selection.start.excerpt_id {
1328                    start = selection.start.text_anchor;
1329                }
1330                if excerpt.id == selection.end.excerpt_id {
1331                    end = selection.end.text_anchor;
1332                }
1333                selections_by_buffer
1334                    .entry(excerpt.buffer_id)
1335                    .or_default()
1336                    .push(Selection {
1337                        id: selection.id,
1338                        start,
1339                        end,
1340                        reversed: selection.reversed,
1341                        goal: selection.goal,
1342                    });
1343
1344                cursor.next();
1345            }
1346        }
1347
1348        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1349            if !selections_by_buffer.contains_key(buffer_id) {
1350                buffer_state
1351                    .buffer
1352                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1353            }
1354        }
1355
1356        for (buffer_id, mut selections) in selections_by_buffer {
1357            self.buffers.borrow()[&buffer_id]
1358                .buffer
1359                .update(cx, |buffer, cx| {
1360                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1361                    let mut selections = selections.into_iter().peekable();
1362                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1363                        let mut selection = selections.next()?;
1364                        while let Some(next_selection) = selections.peek() {
1365                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1366                                let next_selection = selections.next().unwrap();
1367                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1368                                    selection.end = next_selection.end;
1369                                }
1370                            } else {
1371                                break;
1372                            }
1373                        }
1374                        Some(selection)
1375                    }));
1376                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1377                });
1378        }
1379    }
1380
1381    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1382        for buffer in self.buffers.borrow().values() {
1383            buffer
1384                .buffer
1385                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1386        }
1387    }
1388
1389    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1390        let mut transaction_id = None;
1391        if let Some(buffer) = self.as_singleton() {
1392            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1393        } else {
1394            while let Some(transaction) = self.history.pop_undo() {
1395                let mut undone = false;
1396                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1397                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1398                        undone |= buffer.update(cx, |buffer, cx| {
1399                            let undo_to = *buffer_transaction_id;
1400                            if let Some(entry) = buffer.peek_undo_stack() {
1401                                *buffer_transaction_id = entry.transaction_id();
1402                            }
1403                            buffer.undo_to_transaction(undo_to, cx)
1404                        });
1405                    }
1406                }
1407
1408                if undone {
1409                    transaction_id = Some(transaction.id);
1410                    break;
1411                }
1412            }
1413        }
1414
1415        if let Some(transaction_id) = transaction_id {
1416            cx.emit(Event::TransactionUndone { transaction_id });
1417        }
1418
1419        transaction_id
1420    }
1421
1422    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1423        if let Some(buffer) = self.as_singleton() {
1424            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1425        }
1426
1427        while let Some(transaction) = self.history.pop_redo() {
1428            let mut redone = false;
1429            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1430                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1431                    redone |= buffer.update(cx, |buffer, cx| {
1432                        let redo_to = *buffer_transaction_id;
1433                        if let Some(entry) = buffer.peek_redo_stack() {
1434                            *buffer_transaction_id = entry.transaction_id();
1435                        }
1436                        buffer.redo_to_transaction(redo_to, cx)
1437                    });
1438                }
1439            }
1440
1441            if redone {
1442                return Some(transaction.id);
1443            }
1444        }
1445
1446        None
1447    }
1448
1449    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1450        if let Some(buffer) = self.as_singleton() {
1451            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1452        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1453            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1454                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1455                    buffer.update(cx, |buffer, cx| {
1456                        buffer.undo_transaction(*transaction_id, cx)
1457                    });
1458                }
1459            }
1460        }
1461    }
1462
1463    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1464        if let Some(buffer) = self.as_singleton() {
1465            buffer.update(cx, |buffer, _| {
1466                buffer.forget_transaction(transaction_id);
1467            });
1468        } else if let Some(transaction) = self.history.forget(transaction_id) {
1469            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1470                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1471                    state.buffer.update(cx, |buffer, _| {
1472                        buffer.forget_transaction(buffer_transaction_id);
1473                    });
1474                }
1475            }
1476        }
1477    }
1478
1479    pub fn push_excerpts<O>(
1480        &mut self,
1481        buffer: Entity<Buffer>,
1482        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1483        cx: &mut Context<Self>,
1484    ) -> Vec<ExcerptId>
1485    where
1486        O: text::ToOffset,
1487    {
1488        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1489    }
1490
1491    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1492        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1493        let snapshot = self.snapshot(cx);
1494        let excerpt = snapshot.excerpt(*excerpt_id)?;
1495        Some(Anchor::in_buffer(
1496            *excerpt_id,
1497            excerpt.buffer_id,
1498            excerpt.range.context.start,
1499        ))
1500    }
1501
1502    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1503        self.excerpts_by_path.keys()
1504    }
1505
1506    fn expand_excerpts_with_paths(
1507        &mut self,
1508        ids: impl IntoIterator<Item = ExcerptId>,
1509        line_count: u32,
1510        direction: ExpandExcerptDirection,
1511        cx: &mut Context<Self>,
1512    ) {
1513        let grouped = ids
1514            .into_iter()
1515            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1516            .into_iter()
1517            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1518            .collect::<Vec<_>>();
1519        let snapshot = self.snapshot(cx);
1520
1521        for (path, ids) in grouped.into_iter() {
1522            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1523                continue;
1524            };
1525
1526            let ids_to_expand = HashSet::from_iter(ids);
1527            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1528                let excerpt = snapshot.excerpt(*excerpt_id)?;
1529
1530                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1531                if ids_to_expand.contains(excerpt_id) {
1532                    match direction {
1533                        ExpandExcerptDirection::Up => {
1534                            context.start.row = context.start.row.saturating_sub(line_count);
1535                            context.start.column = 0;
1536                        }
1537                        ExpandExcerptDirection::Down => {
1538                            context.end.row =
1539                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1540                            context.end.column = excerpt.buffer.line_len(context.end.row);
1541                        }
1542                        ExpandExcerptDirection::UpAndDown => {
1543                            context.start.row = context.start.row.saturating_sub(line_count);
1544                            context.start.column = 0;
1545                            context.end.row =
1546                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1547                            context.end.column = excerpt.buffer.line_len(context.end.row);
1548                        }
1549                    }
1550                }
1551
1552                Some(ExcerptRange {
1553                    context,
1554                    primary: excerpt.range.primary.to_point(&excerpt.buffer),
1555                })
1556            });
1557            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1558            for range in expanded_ranges {
1559                if let Some(last_range) = merged_ranges.last_mut()
1560                    && last_range.context.end >= range.context.start
1561                {
1562                    last_range.context.end = range.context.end;
1563                    continue;
1564                }
1565                merged_ranges.push(range)
1566            }
1567            let Some(excerpt_id) = excerpt_ids.first() else {
1568                continue;
1569            };
1570            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1571                continue;
1572            };
1573
1574            let Some(buffer) = self
1575                .buffers
1576                .borrow()
1577                .get(buffer_id)
1578                .map(|b| b.buffer.clone())
1579            else {
1580                continue;
1581            };
1582
1583            let buffer_snapshot = buffer.read(cx).snapshot();
1584            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1585        }
1586    }
1587
1588    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1589    pub fn set_excerpts_for_path(
1590        &mut self,
1591        path: PathKey,
1592        buffer: Entity<Buffer>,
1593        ranges: impl IntoIterator<Item = Range<Point>>,
1594        context_line_count: u32,
1595        cx: &mut Context<Self>,
1596    ) -> (Vec<Range<Anchor>>, bool) {
1597        let buffer_snapshot = buffer.read(cx).snapshot();
1598        let excerpt_ranges = build_excerpt_ranges(ranges, context_line_count, &buffer_snapshot);
1599
1600        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1601        self.set_merged_excerpt_ranges_for_path(
1602            path,
1603            buffer,
1604            excerpt_ranges,
1605            &buffer_snapshot,
1606            new,
1607            counts,
1608            cx,
1609        )
1610    }
1611
1612    pub fn set_excerpt_ranges_for_path(
1613        &mut self,
1614        path: PathKey,
1615        buffer: Entity<Buffer>,
1616        buffer_snapshot: &BufferSnapshot,
1617        excerpt_ranges: Vec<ExcerptRange<Point>>,
1618        cx: &mut Context<Self>,
1619    ) -> (Vec<Range<Anchor>>, bool) {
1620        let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1621        self.set_merged_excerpt_ranges_for_path(
1622            path,
1623            buffer,
1624            excerpt_ranges,
1625            buffer_snapshot,
1626            new,
1627            counts,
1628            cx,
1629        )
1630    }
1631
1632    pub fn set_anchored_excerpts_for_path(
1633        &self,
1634        buffer: Entity<Buffer>,
1635        ranges: Vec<Range<text::Anchor>>,
1636        context_line_count: u32,
1637        cx: &mut Context<Self>,
1638    ) -> Task<Vec<Range<Anchor>>> {
1639        let buffer_snapshot = buffer.read(cx).snapshot();
1640        let path_key = PathKey::for_buffer(&buffer, cx);
1641        cx.spawn(async move |multi_buffer, cx| {
1642            let snapshot = buffer_snapshot.clone();
1643            let (excerpt_ranges, new, counts) = cx
1644                .background_spawn(async move {
1645                    let ranges = ranges.into_iter().map(|range| range.to_point(&snapshot));
1646                    let excerpt_ranges =
1647                        build_excerpt_ranges(ranges, context_line_count, &snapshot);
1648                    let (new, counts) = Self::merge_excerpt_ranges(&excerpt_ranges);
1649                    (excerpt_ranges, new, counts)
1650                })
1651                .await;
1652
1653            multi_buffer
1654                .update(cx, move |multi_buffer, cx| {
1655                    let (ranges, _) = multi_buffer.set_merged_excerpt_ranges_for_path(
1656                        path_key,
1657                        buffer,
1658                        excerpt_ranges,
1659                        &buffer_snapshot,
1660                        new,
1661                        counts,
1662                        cx,
1663                    );
1664                    ranges
1665                })
1666                .ok()
1667                .unwrap_or_default()
1668        })
1669    }
1670
1671    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1672    fn set_merged_excerpt_ranges_for_path(
1673        &mut self,
1674        path: PathKey,
1675        buffer: Entity<Buffer>,
1676        ranges: Vec<ExcerptRange<Point>>,
1677        buffer_snapshot: &BufferSnapshot,
1678        new: Vec<ExcerptRange<Point>>,
1679        counts: Vec<usize>,
1680        cx: &mut Context<Self>,
1681    ) -> (Vec<Range<Anchor>>, bool) {
1682        let (excerpt_ids, added_a_new_excerpt) =
1683            self.update_path_excerpts(path, buffer, buffer_snapshot, new, cx);
1684
1685        let mut result = Vec::new();
1686        let mut ranges = ranges.into_iter();
1687        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(counts.into_iter()) {
1688            for range in ranges.by_ref().take(range_count) {
1689                let range = Anchor::range_in_buffer(
1690                    excerpt_id,
1691                    buffer_snapshot.remote_id(),
1692                    buffer_snapshot.anchor_before(&range.primary.start)
1693                        ..buffer_snapshot.anchor_after(&range.primary.end),
1694                );
1695                result.push(range)
1696            }
1697        }
1698        (result, added_a_new_excerpt)
1699    }
1700
1701    fn merge_excerpt_ranges<'a>(
1702        expanded_ranges: impl IntoIterator<Item = &'a ExcerptRange<Point>> + 'a,
1703    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1704        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1705        let mut counts: Vec<usize> = Vec::new();
1706        for range in expanded_ranges {
1707            if let Some(last_range) = merged_ranges.last_mut() {
1708                debug_assert!(
1709                    last_range.context.start <= range.context.start,
1710                    "Last range: {last_range:?} Range: {range:?}"
1711                );
1712                if last_range.context.end >= range.context.start
1713                    || last_range.context.end.row + 1 == range.context.start.row
1714                {
1715                    last_range.context.end = range.context.end.max(last_range.context.end);
1716                    *counts.last_mut().unwrap() += 1;
1717                    continue;
1718                }
1719            }
1720            merged_ranges.push(range.clone());
1721            counts.push(1);
1722        }
1723        (merged_ranges, counts)
1724    }
1725
1726    fn update_path_excerpts(
1727        &mut self,
1728        path: PathKey,
1729        buffer: Entity<Buffer>,
1730        buffer_snapshot: &BufferSnapshot,
1731        new: Vec<ExcerptRange<Point>>,
1732        cx: &mut Context<Self>,
1733    ) -> (Vec<ExcerptId>, bool) {
1734        let mut insert_after = self
1735            .excerpts_by_path
1736            .range(..path.clone())
1737            .next_back()
1738            .map(|(_, value)| *value.last().unwrap())
1739            .unwrap_or(ExcerptId::min());
1740
1741        let existing = self
1742            .excerpts_by_path
1743            .get(&path)
1744            .cloned()
1745            .unwrap_or_default();
1746
1747        let mut new_iter = new.into_iter().peekable();
1748        let mut existing_iter = existing.into_iter().peekable();
1749
1750        let mut excerpt_ids = Vec::new();
1751        let mut to_remove = Vec::new();
1752        let mut to_insert: Vec<(ExcerptId, ExcerptRange<Point>)> = Vec::new();
1753        let mut added_a_new_excerpt = false;
1754        let snapshot = self.snapshot(cx);
1755
1756        let mut next_excerpt_id =
1757            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1758                last_entry.id.0 + 1
1759            } else {
1760                1
1761            };
1762
1763        let mut next_excerpt_id = move || ExcerptId(post_inc(&mut next_excerpt_id));
1764
1765        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1766        excerpts_cursor.next();
1767
1768        loop {
1769            let new = new_iter.peek();
1770            let existing = if let Some(existing_id) = existing_iter.peek() {
1771                let locator = snapshot.excerpt_locator_for_id(*existing_id);
1772                excerpts_cursor.seek_forward(&Some(locator), Bias::Left);
1773                if let Some(excerpt) = excerpts_cursor.item() {
1774                    if excerpt.buffer_id != buffer_snapshot.remote_id() {
1775                        to_remove.push(*existing_id);
1776                        existing_iter.next();
1777                        continue;
1778                    }
1779                    Some((
1780                        *existing_id,
1781                        excerpt.range.context.to_point(buffer_snapshot),
1782                    ))
1783                } else {
1784                    None
1785                }
1786            } else {
1787                None
1788            };
1789
1790            if let Some((last_id, last)) = to_insert.last_mut() {
1791                if let Some(new) = new
1792                    && last.context.end >= new.context.start
1793                {
1794                    last.context.end = last.context.end.max(new.context.end);
1795                    excerpt_ids.push(*last_id);
1796                    new_iter.next();
1797                    continue;
1798                }
1799                if let Some((existing_id, existing_range)) = &existing
1800                    && last.context.end >= existing_range.start
1801                {
1802                    last.context.end = last.context.end.max(existing_range.end);
1803                    to_remove.push(*existing_id);
1804                    self.snapshot
1805                        .borrow_mut()
1806                        .replaced_excerpts
1807                        .insert(*existing_id, *last_id);
1808                    existing_iter.next();
1809                    continue;
1810                }
1811            }
1812
1813            match (new, existing) {
1814                (None, None) => break,
1815                (None, Some((existing_id, _))) => {
1816                    existing_iter.next();
1817                    to_remove.push(existing_id);
1818                    continue;
1819                }
1820                (Some(_), None) => {
1821                    added_a_new_excerpt = true;
1822                    let new_id = next_excerpt_id();
1823                    excerpt_ids.push(new_id);
1824                    to_insert.push((new_id, new_iter.next().unwrap()));
1825                    continue;
1826                }
1827                (Some(new), Some((_, existing_range))) => {
1828                    if existing_range.end < new.context.start {
1829                        let existing_id = existing_iter.next().unwrap();
1830                        to_remove.push(existing_id);
1831                        continue;
1832                    } else if existing_range.start > new.context.end {
1833                        let new_id = next_excerpt_id();
1834                        excerpt_ids.push(new_id);
1835                        to_insert.push((new_id, new_iter.next().unwrap()));
1836                        continue;
1837                    }
1838
1839                    if existing_range.start == new.context.start
1840                        && existing_range.end == new.context.end
1841                    {
1842                        self.insert_excerpts_with_ids_after(
1843                            insert_after,
1844                            buffer.clone(),
1845                            mem::take(&mut to_insert),
1846                            cx,
1847                        );
1848                        insert_after = existing_iter.next().unwrap();
1849                        excerpt_ids.push(insert_after);
1850                        new_iter.next();
1851                    } else {
1852                        let existing_id = existing_iter.next().unwrap();
1853                        let new_id = next_excerpt_id();
1854                        self.snapshot
1855                            .borrow_mut()
1856                            .replaced_excerpts
1857                            .insert(existing_id, new_id);
1858                        to_remove.push(existing_id);
1859                        let mut range = new_iter.next().unwrap();
1860                        range.context.start = range.context.start.min(existing_range.start);
1861                        range.context.end = range.context.end.max(existing_range.end);
1862                        excerpt_ids.push(new_id);
1863                        to_insert.push((new_id, range));
1864                    }
1865                }
1866            };
1867        }
1868
1869        self.insert_excerpts_with_ids_after(insert_after, buffer, to_insert, cx);
1870        self.remove_excerpts(to_remove, cx);
1871        if excerpt_ids.is_empty() {
1872            self.excerpts_by_path.remove(&path);
1873        } else {
1874            for excerpt_id in &excerpt_ids {
1875                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1876            }
1877            self.excerpts_by_path
1878                .insert(path, excerpt_ids.iter().dedup().cloned().collect());
1879        }
1880
1881        (excerpt_ids, added_a_new_excerpt)
1882    }
1883
1884    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1885        self.excerpts_by_path.keys().cloned()
1886    }
1887
1888    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1889        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1890            self.remove_excerpts(to_remove, cx)
1891        }
1892    }
1893
1894    pub fn insert_excerpts_after<O>(
1895        &mut self,
1896        prev_excerpt_id: ExcerptId,
1897        buffer: Entity<Buffer>,
1898        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1899        cx: &mut Context<Self>,
1900    ) -> Vec<ExcerptId>
1901    where
1902        O: text::ToOffset,
1903    {
1904        let mut ids = Vec::new();
1905        let mut next_excerpt_id =
1906            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1907                last_entry.id.0 + 1
1908            } else {
1909                1
1910            };
1911        self.insert_excerpts_with_ids_after(
1912            prev_excerpt_id,
1913            buffer,
1914            ranges.into_iter().map(|range| {
1915                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1916                ids.push(id);
1917                (id, range)
1918            }),
1919            cx,
1920        );
1921        ids
1922    }
1923
1924    pub fn insert_excerpts_with_ids_after<O>(
1925        &mut self,
1926        prev_excerpt_id: ExcerptId,
1927        buffer: Entity<Buffer>,
1928        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1929        cx: &mut Context<Self>,
1930    ) where
1931        O: text::ToOffset,
1932    {
1933        assert_eq!(self.history.transaction_depth, 0);
1934        let mut ranges = ranges.into_iter().peekable();
1935        if ranges.peek().is_none() {
1936            return Default::default();
1937        }
1938
1939        self.sync(cx);
1940
1941        let buffer_snapshot = buffer.read(cx).snapshot();
1942        let buffer_id = buffer_snapshot.remote_id();
1943
1944        let mut buffers = self.buffers.borrow_mut();
1945        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1946            self.buffer_changed_since_sync.replace(true);
1947            buffer.update(cx, |buffer, _| {
1948                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1949            });
1950            BufferState {
1951                last_version: buffer_snapshot.version().clone(),
1952                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1953                excerpts: Default::default(),
1954                _subscriptions: [
1955                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1956                    cx.subscribe(&buffer, Self::on_buffer_event),
1957                ],
1958                buffer: buffer.clone(),
1959            }
1960        });
1961
1962        let mut snapshot = self.snapshot.borrow_mut();
1963
1964        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1965        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1966        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1967        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right);
1968        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1969
1970        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1971        new_excerpts.update_last(
1972            |excerpt| {
1973                excerpt.has_trailing_newline = true;
1974            },
1975            &(),
1976        );
1977
1978        let next_locator = if let Some(excerpt) = cursor.item() {
1979            excerpt.locator.clone()
1980        } else {
1981            Locator::max()
1982        };
1983
1984        let mut excerpts = Vec::new();
1985        while let Some((id, range)) = ranges.next() {
1986            let locator = Locator::between(&prev_locator, &next_locator);
1987            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1988                buffer_state.excerpts.insert(ix, locator.clone());
1989            }
1990            let range = ExcerptRange {
1991                context: buffer_snapshot.anchor_before(&range.context.start)
1992                    ..buffer_snapshot.anchor_after(&range.context.end),
1993                primary: buffer_snapshot.anchor_before(&range.primary.start)
1994                    ..buffer_snapshot.anchor_after(&range.primary.end),
1995            };
1996            excerpts.push((id, range.clone()));
1997            let excerpt = Excerpt::new(
1998                id,
1999                locator.clone(),
2000                buffer_id,
2001                buffer_snapshot.clone(),
2002                range,
2003                ranges.peek().is_some() || cursor.item().is_some(),
2004            );
2005            new_excerpts.push(excerpt, &());
2006            prev_locator = locator.clone();
2007
2008            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
2009                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
2010            }
2011            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
2012        }
2013
2014        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
2015
2016        let suffix = cursor.suffix();
2017        let changed_trailing_excerpt = suffix.is_empty();
2018        new_excerpts.append(suffix, &());
2019        drop(cursor);
2020        snapshot.excerpts = new_excerpts;
2021        snapshot.excerpt_ids = new_excerpt_ids;
2022        if changed_trailing_excerpt {
2023            snapshot.trailing_excerpt_update_count += 1;
2024        }
2025
2026        self.sync_diff_transforms(
2027            &mut snapshot,
2028            vec![Edit {
2029                old: edit_start..edit_start,
2030                new: edit_start..edit_end,
2031            }],
2032            DiffChangeKind::BufferEdited,
2033        );
2034        cx.emit(Event::Edited {
2035            singleton_buffer_edited: false,
2036            edited_buffer: None,
2037        });
2038        cx.emit(Event::ExcerptsAdded {
2039            buffer,
2040            predecessor: prev_excerpt_id,
2041            excerpts,
2042        });
2043        cx.notify();
2044    }
2045
2046    pub fn clear(&mut self, cx: &mut Context<Self>) {
2047        self.sync(cx);
2048        let ids = self.excerpt_ids();
2049        let removed_buffer_ids = self
2050            .buffers
2051            .borrow_mut()
2052            .drain()
2053            .map(|(id, _)| id)
2054            .collect();
2055        self.excerpts_by_path.clear();
2056        self.paths_by_excerpt.clear();
2057        let mut snapshot = self.snapshot.borrow_mut();
2058        let start = ExcerptOffset::new(0);
2059        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
2060        snapshot.excerpts = Default::default();
2061        snapshot.trailing_excerpt_update_count += 1;
2062        snapshot.is_dirty = false;
2063        snapshot.has_deleted_file = false;
2064        snapshot.has_conflict = false;
2065        snapshot.replaced_excerpts.clear();
2066
2067        self.sync_diff_transforms(
2068            &mut snapshot,
2069            vec![Edit {
2070                old: start..prev_len,
2071                new: start..start,
2072            }],
2073            DiffChangeKind::BufferEdited,
2074        );
2075        cx.emit(Event::Edited {
2076            singleton_buffer_edited: false,
2077            edited_buffer: None,
2078        });
2079        cx.emit(Event::ExcerptsRemoved {
2080            ids,
2081            removed_buffer_ids,
2082        });
2083        cx.notify();
2084    }
2085
2086    pub fn excerpts_for_buffer(
2087        &self,
2088        buffer_id: BufferId,
2089        cx: &App,
2090    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2091        let mut excerpts = Vec::new();
2092        let snapshot = self.read(cx);
2093        let buffers = self.buffers.borrow();
2094        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2095        for locator in buffers
2096            .get(&buffer_id)
2097            .map(|state| &state.excerpts)
2098            .into_iter()
2099            .flatten()
2100        {
2101            cursor.seek_forward(&Some(locator), Bias::Left);
2102            if let Some(excerpt) = cursor.item()
2103                && excerpt.locator == *locator
2104            {
2105                excerpts.push((excerpt.id, excerpt.range.clone()));
2106            }
2107        }
2108
2109        excerpts
2110    }
2111
2112    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2113        let snapshot = self.read(cx);
2114        let buffers = self.buffers.borrow();
2115        let mut excerpts = snapshot
2116            .excerpts
2117            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(&());
2118        let mut diff_transforms = snapshot
2119            .diff_transforms
2120            .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(&());
2121        diff_transforms.next();
2122        let locators = buffers
2123            .get(&buffer_id)
2124            .into_iter()
2125            .flat_map(|state| &state.excerpts);
2126        let mut result = Vec::new();
2127        for locator in locators {
2128            excerpts.seek_forward(&Some(locator), Bias::Left);
2129            if let Some(excerpt) = excerpts.item()
2130                && excerpt.locator == *locator
2131            {
2132                let excerpt_start = excerpts.start().1.clone();
2133                let excerpt_end = ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2134
2135                diff_transforms.seek_forward(&excerpt_start, Bias::Left);
2136                let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
2137                let start = diff_transforms.start().1.0 + overshoot;
2138
2139                diff_transforms.seek_forward(&excerpt_end, Bias::Right);
2140                let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
2141                let end = diff_transforms.start().1.0 + overshoot;
2142
2143                result.push(start..end)
2144            }
2145        }
2146        result
2147    }
2148
2149    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2150        self.snapshot
2151            .borrow()
2152            .excerpts
2153            .iter()
2154            .map(|entry| entry.buffer_id)
2155            .collect()
2156    }
2157
2158    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2159        self.snapshot
2160            .borrow()
2161            .excerpts
2162            .iter()
2163            .map(|entry| entry.id)
2164            .collect()
2165    }
2166
2167    pub fn excerpt_containing(
2168        &self,
2169        position: impl ToOffset,
2170        cx: &App,
2171    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2172        let snapshot = self.read(cx);
2173        let offset = position.to_offset(&snapshot);
2174
2175        let mut cursor = snapshot.cursor::<usize>();
2176        cursor.seek(&offset);
2177        cursor
2178            .excerpt()
2179            .or_else(|| snapshot.excerpts.last())
2180            .map(|excerpt| {
2181                (
2182                    excerpt.id,
2183                    self.buffers
2184                        .borrow()
2185                        .get(&excerpt.buffer_id)
2186                        .unwrap()
2187                        .buffer
2188                        .clone(),
2189                    excerpt.range.context.clone(),
2190                )
2191            })
2192    }
2193
2194    pub fn buffer_for_anchor(&self, anchor: Anchor, cx: &App) -> Option<Entity<Buffer>> {
2195        if let Some(buffer_id) = anchor.buffer_id {
2196            self.buffer(buffer_id)
2197        } else {
2198            let (_, buffer, _) = self.excerpt_containing(anchor, cx)?;
2199            Some(buffer)
2200        }
2201    }
2202
2203    // If point is at the end of the buffer, the last excerpt is returned
2204    pub fn point_to_buffer_offset<T: ToOffset>(
2205        &self,
2206        point: T,
2207        cx: &App,
2208    ) -> Option<(Entity<Buffer>, usize)> {
2209        let snapshot = self.read(cx);
2210        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2211        Some((
2212            self.buffers
2213                .borrow()
2214                .get(&buffer.remote_id())?
2215                .buffer
2216                .clone(),
2217            offset,
2218        ))
2219    }
2220
2221    // If point is at the end of the buffer, the last excerpt is returned
2222    pub fn point_to_buffer_point<T: ToPoint>(
2223        &self,
2224        point: T,
2225        cx: &App,
2226    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2227        let snapshot = self.read(cx);
2228        let (buffer, point, is_main_buffer) =
2229            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2230        Some((
2231            self.buffers
2232                .borrow()
2233                .get(&buffer.remote_id())?
2234                .buffer
2235                .clone(),
2236            point,
2237            is_main_buffer,
2238        ))
2239    }
2240
2241    pub fn buffer_point_to_anchor(
2242        &self,
2243        buffer: &Entity<Buffer>,
2244        point: Point,
2245        cx: &App,
2246    ) -> Option<Anchor> {
2247        let mut found = None;
2248        let snapshot = buffer.read(cx).snapshot();
2249        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2250            let start = range.context.start.to_point(&snapshot);
2251            let end = range.context.end.to_point(&snapshot);
2252            if start <= point && point < end {
2253                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2254                break;
2255            }
2256            if point < start {
2257                found = Some((start, excerpt_id));
2258            }
2259            if point > end {
2260                found = Some((end, excerpt_id));
2261            }
2262        }
2263
2264        found.map(|(point, excerpt_id)| {
2265            let text_anchor = snapshot.anchor_after(point);
2266            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2267        })
2268    }
2269
2270    pub fn remove_excerpts(
2271        &mut self,
2272        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2273        cx: &mut Context<Self>,
2274    ) {
2275        self.sync(cx);
2276        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2277        if ids.is_empty() {
2278            return;
2279        }
2280
2281        let mut buffers = self.buffers.borrow_mut();
2282        let mut snapshot = self.snapshot.borrow_mut();
2283        let mut new_excerpts = SumTree::default();
2284        let mut cursor = snapshot
2285            .excerpts
2286            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2287        let mut edits = Vec::new();
2288        let mut excerpt_ids = ids.iter().copied().peekable();
2289        let mut removed_buffer_ids = Vec::new();
2290
2291        while let Some(excerpt_id) = excerpt_ids.next() {
2292            self.paths_by_excerpt.remove(&excerpt_id);
2293            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2294            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2295            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), &());
2296
2297            if let Some(mut excerpt) = cursor.item() {
2298                if excerpt.id != excerpt_id {
2299                    continue;
2300                }
2301                let mut old_start = cursor.start().1;
2302
2303                // Skip over the removed excerpt.
2304                'remove_excerpts: loop {
2305                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2306                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2307                        if buffer_state.excerpts.is_empty() {
2308                            log::debug!(
2309                                "removing buffer and diff for buffer {}",
2310                                excerpt.buffer_id
2311                            );
2312                            buffers.remove(&excerpt.buffer_id);
2313                            removed_buffer_ids.push(excerpt.buffer_id);
2314                        }
2315                    }
2316                    cursor.next();
2317
2318                    // Skip over any subsequent excerpts that are also removed.
2319                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2320                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2321                        if let Some(next_excerpt) = cursor.item()
2322                            && next_excerpt.locator == *next_locator
2323                        {
2324                            excerpt_ids.next();
2325                            excerpt = next_excerpt;
2326                            continue 'remove_excerpts;
2327                        }
2328                    }
2329
2330                    break;
2331                }
2332
2333                // When removing the last excerpt, remove the trailing newline from
2334                // the previous excerpt.
2335                if cursor.item().is_none() && old_start.value > 0 {
2336                    old_start.value -= 1;
2337                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2338                }
2339
2340                // Push an edit for the removal of this run of excerpts.
2341                let old_end = cursor.start().1;
2342                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2343                edits.push(Edit {
2344                    old: old_start..old_end,
2345                    new: new_start..new_start,
2346                });
2347            }
2348        }
2349        let suffix = cursor.suffix();
2350        let changed_trailing_excerpt = suffix.is_empty();
2351        new_excerpts.append(suffix, &());
2352        drop(cursor);
2353        snapshot.excerpts = new_excerpts;
2354        for buffer_id in &removed_buffer_ids {
2355            self.diffs.remove(buffer_id);
2356            snapshot.diffs.remove(buffer_id);
2357        }
2358
2359        if changed_trailing_excerpt {
2360            snapshot.trailing_excerpt_update_count += 1;
2361        }
2362
2363        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2364        self.buffer_changed_since_sync.replace(true);
2365        cx.emit(Event::Edited {
2366            singleton_buffer_edited: false,
2367            edited_buffer: None,
2368        });
2369        cx.emit(Event::ExcerptsRemoved {
2370            ids,
2371            removed_buffer_ids,
2372        });
2373        cx.notify();
2374    }
2375
2376    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2377        &self,
2378        anchors: Anchors,
2379        cx: &mut Context<Self>,
2380    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2381        let borrow = self.buffers.borrow();
2382        let mut error = None;
2383        let mut futures = Vec::new();
2384        for anchor in anchors {
2385            if let Some(buffer_id) = anchor.buffer_id {
2386                if let Some(buffer) = borrow.get(&buffer_id) {
2387                    buffer.buffer.update(cx, |buffer, _| {
2388                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2389                    });
2390                } else {
2391                    error = Some(anyhow!(
2392                        "buffer {buffer_id} is not part of this multi-buffer"
2393                    ));
2394                    break;
2395                }
2396            }
2397        }
2398        async move {
2399            if let Some(error) = error {
2400                Err(error)?;
2401            }
2402            for future in futures {
2403                future.await?;
2404            }
2405            Ok(())
2406        }
2407    }
2408
2409    pub fn text_anchor_for_position<T: ToOffset>(
2410        &self,
2411        position: T,
2412        cx: &App,
2413    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2414        let snapshot = self.read(cx);
2415        let anchor = snapshot.anchor_before(position);
2416        let buffer = self
2417            .buffers
2418            .borrow()
2419            .get(&anchor.buffer_id?)?
2420            .buffer
2421            .clone();
2422        Some((buffer, anchor.text_anchor))
2423    }
2424
2425    fn on_buffer_event(
2426        &mut self,
2427        buffer: Entity<Buffer>,
2428        event: &language::BufferEvent,
2429        cx: &mut Context<Self>,
2430    ) {
2431        use language::BufferEvent;
2432        cx.emit(match event {
2433            BufferEvent::Edited => Event::Edited {
2434                singleton_buffer_edited: true,
2435                edited_buffer: Some(buffer),
2436            },
2437            BufferEvent::DirtyChanged => Event::DirtyChanged,
2438            BufferEvent::Saved => Event::Saved,
2439            BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2440            BufferEvent::Reloaded => Event::Reloaded,
2441            BufferEvent::LanguageChanged => Event::LanguageChanged(buffer.read(cx).remote_id()),
2442            BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2443            BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2444            BufferEvent::CapabilityChanged => {
2445                self.capability = buffer.read(cx).capability();
2446                return;
2447            }
2448            BufferEvent::Operation { .. } | BufferEvent::ReloadNeeded => return,
2449        });
2450    }
2451
2452    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2453        self.sync(cx);
2454        let mut snapshot = self.snapshot.borrow_mut();
2455        let diff = diff.read(cx);
2456        let buffer_id = diff.buffer_id;
2457        let diff = diff.snapshot(cx);
2458        snapshot.diffs.insert(buffer_id, diff);
2459    }
2460
2461    fn buffer_diff_changed(
2462        &mut self,
2463        diff: Entity<BufferDiff>,
2464        range: Range<text::Anchor>,
2465        cx: &mut Context<Self>,
2466    ) {
2467        self.sync(cx);
2468        self.buffer_changed_since_sync.replace(true);
2469
2470        let diff = diff.read(cx);
2471        let buffer_id = diff.buffer_id;
2472        let buffers = self.buffers.borrow();
2473        let Some(buffer_state) = buffers.get(&buffer_id) else {
2474            return;
2475        };
2476
2477        let buffer = buffer_state.buffer.read(cx);
2478        let diff_change_range = range.to_offset(buffer);
2479
2480        let new_diff = diff.snapshot(cx);
2481        let mut snapshot = self.snapshot.borrow_mut();
2482        let base_text_changed = snapshot
2483            .diffs
2484            .get(&buffer_id)
2485            .is_none_or(|old_diff| !new_diff.base_texts_eq(old_diff));
2486
2487        snapshot.diffs.insert(buffer_id, new_diff);
2488
2489        let mut excerpt_edits = Vec::new();
2490        for locator in &buffer_state.excerpts {
2491            let mut cursor = snapshot
2492                .excerpts
2493                .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2494            cursor.seek_forward(&Some(locator), Bias::Left);
2495            if let Some(excerpt) = cursor.item()
2496                && excerpt.locator == *locator
2497            {
2498                let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2499                if diff_change_range.end < excerpt_buffer_range.start
2500                    || diff_change_range.start > excerpt_buffer_range.end
2501                {
2502                    continue;
2503                }
2504                let excerpt_start = cursor.start().1;
2505                let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2506                let diff_change_start_in_excerpt = ExcerptOffset::new(
2507                    diff_change_range
2508                        .start
2509                        .saturating_sub(excerpt_buffer_range.start),
2510                );
2511                let diff_change_end_in_excerpt = ExcerptOffset::new(
2512                    diff_change_range
2513                        .end
2514                        .saturating_sub(excerpt_buffer_range.start),
2515                );
2516                let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2517                let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2518                excerpt_edits.push(Edit {
2519                    old: edit_start..edit_end,
2520                    new: edit_start..edit_end,
2521                });
2522            }
2523        }
2524
2525        self.sync_diff_transforms(
2526            &mut snapshot,
2527            excerpt_edits,
2528            DiffChangeKind::DiffUpdated {
2529                base_changed: base_text_changed,
2530            },
2531        );
2532        cx.emit(Event::Edited {
2533            singleton_buffer_edited: false,
2534            edited_buffer: None,
2535        });
2536    }
2537
2538    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2539        self.buffers
2540            .borrow()
2541            .values()
2542            .map(|state| state.buffer.clone())
2543            .collect()
2544    }
2545
2546    pub fn all_buffer_ids(&self) -> Vec<BufferId> {
2547        self.buffers.borrow().keys().copied().collect()
2548    }
2549
2550    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2551        self.buffers
2552            .borrow()
2553            .get(&buffer_id)
2554            .map(|state| state.buffer.clone())
2555    }
2556
2557    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2558        self.point_to_buffer_offset(point, cx)
2559            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2560    }
2561
2562    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2563        let buffer_id = self
2564            .snapshot
2565            .borrow()
2566            .excerpts
2567            .first()
2568            .map(|excerpt| excerpt.buffer.remote_id());
2569        buffer_id
2570            .and_then(|buffer_id| self.buffer(buffer_id))
2571            .map(|buffer| {
2572                let buffer = buffer.read(cx);
2573                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2574            })
2575            .unwrap_or_else(move || self.language_settings_at(0, cx))
2576    }
2577
2578    pub fn language_settings_at<'a, T: ToOffset>(
2579        &'a self,
2580        point: T,
2581        cx: &'a App,
2582    ) -> Cow<'a, LanguageSettings> {
2583        let mut language = None;
2584        let mut file = None;
2585        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2586            let buffer = buffer.read(cx);
2587            language = buffer.language_at(offset);
2588            file = buffer.file();
2589        }
2590        language_settings(language.map(|l| l.name()), file, cx)
2591    }
2592
2593    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2594        self.buffers
2595            .borrow()
2596            .values()
2597            .for_each(|state| f(&state.buffer))
2598    }
2599
2600    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2601        if let Some(title) = self.title.as_ref() {
2602            return title.into();
2603        }
2604
2605        if let Some(buffer) = self.as_singleton() {
2606            let buffer = buffer.read(cx);
2607
2608            if let Some(file) = buffer.file() {
2609                return file.file_name(cx).to_string_lossy();
2610            }
2611
2612            if let Some(title) = self.buffer_content_title(buffer) {
2613                return title;
2614            }
2615        };
2616
2617        "untitled".into()
2618    }
2619
2620    fn buffer_content_title(&self, buffer: &Buffer) -> Option<Cow<'_, str>> {
2621        let mut is_leading_whitespace = true;
2622        let mut count = 0;
2623        let mut prev_was_space = false;
2624        let mut title = String::new();
2625
2626        for ch in buffer.snapshot().chars() {
2627            if is_leading_whitespace && ch.is_whitespace() {
2628                continue;
2629            }
2630
2631            is_leading_whitespace = false;
2632
2633            if ch == '\n' || count >= 40 {
2634                break;
2635            }
2636
2637            if ch.is_whitespace() {
2638                if !prev_was_space {
2639                    title.push(' ');
2640                    count += 1;
2641                    prev_was_space = true;
2642                }
2643            } else {
2644                title.push(ch);
2645                count += 1;
2646                prev_was_space = false;
2647            }
2648        }
2649
2650        let title = title.trim_end().to_string();
2651
2652        if title.is_empty() {
2653            return None;
2654        }
2655
2656        Some(title.into())
2657    }
2658
2659    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2660        self.title = Some(title);
2661        cx.notify();
2662    }
2663
2664    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2665    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2666        for buffer_state in self.buffers.borrow().values() {
2667            buffer_state
2668                .buffer
2669                .update(cx, |buffer, _cx| buffer.refresh_preview());
2670        }
2671    }
2672
2673    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2674    pub fn preserve_preview(&self, cx: &App) -> bool {
2675        self.buffers
2676            .borrow()
2677            .values()
2678            .all(|state| state.buffer.read(cx).preserve_preview())
2679    }
2680
2681    #[cfg(any(test, feature = "test-support"))]
2682    pub fn is_parsing(&self, cx: &App) -> bool {
2683        self.as_singleton().unwrap().read(cx).is_parsing()
2684    }
2685
2686    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2687        let buffer_id = diff.read(cx).buffer_id;
2688        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2689        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2690    }
2691
2692    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2693        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2694    }
2695
2696    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2697        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2698    }
2699
2700    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2701        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2702    }
2703
2704    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2705        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2706        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2707    }
2708
2709    pub fn all_diff_hunks_expanded(&self) -> bool {
2710        self.snapshot.borrow().all_diff_hunks_expanded
2711    }
2712
2713    pub fn set_all_diff_hunks_collapsed(&mut self, cx: &mut Context<Self>) {
2714        self.snapshot.borrow_mut().all_diff_hunks_expanded = false;
2715        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], false, cx);
2716    }
2717
2718    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2719        self.read(cx)
2720            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2721            .nth(1)
2722            .is_some()
2723    }
2724
2725    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2726        let snapshot = self.read(cx);
2727        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2728        let offset_range = range.to_offset(&snapshot);
2729        cursor.seek(&offset_range.start, Bias::Left);
2730        while let Some(item) = cursor.item() {
2731            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2732                break;
2733            }
2734            if item.hunk_info().is_some() {
2735                return true;
2736            }
2737            cursor.next();
2738        }
2739        false
2740    }
2741
2742    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2743        let snapshot = self.read(cx);
2744        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2745        for range in ranges {
2746            let range = range.to_point(&snapshot);
2747            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2748            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2749            let start = start.saturating_sub(1);
2750            let end = snapshot.len().min(end + 1);
2751            cursor.seek(&start, Bias::Right);
2752            while let Some(item) = cursor.item() {
2753                if *cursor.start() >= end {
2754                    break;
2755                }
2756                if item.hunk_info().is_some() {
2757                    return true;
2758                }
2759                cursor.next();
2760            }
2761        }
2762        false
2763    }
2764
2765    pub fn expand_or_collapse_diff_hunks_inner(
2766        &mut self,
2767        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2768        expand: bool,
2769        cx: &mut Context<Self>,
2770    ) {
2771        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2772            return;
2773        }
2774        self.sync(cx);
2775        let mut snapshot = self.snapshot.borrow_mut();
2776        let mut excerpt_edits = Vec::new();
2777        let mut last_hunk_row = None;
2778        for (range, end_excerpt_id) in ranges {
2779            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2780                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2781                    continue;
2782                }
2783                if last_hunk_row.is_some_and(|row| row >= diff_hunk.row_range.start) {
2784                    continue;
2785                }
2786                let start = Anchor::in_buffer(
2787                    diff_hunk.excerpt_id,
2788                    diff_hunk.buffer_id,
2789                    diff_hunk.buffer_range.start,
2790                );
2791                let end = Anchor::in_buffer(
2792                    diff_hunk.excerpt_id,
2793                    diff_hunk.buffer_id,
2794                    diff_hunk.buffer_range.end,
2795                );
2796                let start = snapshot.excerpt_offset_for_anchor(&start);
2797                let end = snapshot.excerpt_offset_for_anchor(&end);
2798                last_hunk_row = Some(diff_hunk.row_range.start);
2799                excerpt_edits.push(text::Edit {
2800                    old: start..end,
2801                    new: start..end,
2802                });
2803            }
2804        }
2805
2806        self.sync_diff_transforms(
2807            &mut snapshot,
2808            excerpt_edits,
2809            DiffChangeKind::ExpandOrCollapseHunks { expand },
2810        );
2811        cx.emit(Event::DiffHunksToggled);
2812        cx.emit(Event::Edited {
2813            singleton_buffer_edited: false,
2814            edited_buffer: None,
2815        });
2816    }
2817
2818    pub fn expand_or_collapse_diff_hunks(
2819        &mut self,
2820        ranges: Vec<Range<Anchor>>,
2821        expand: bool,
2822        cx: &mut Context<Self>,
2823    ) {
2824        let snapshot = self.snapshot.borrow().clone();
2825        let ranges = ranges.iter().map(move |range| {
2826            let end_excerpt_id = range.end.excerpt_id;
2827            let range = range.to_point(&snapshot);
2828            let mut peek_end = range.end;
2829            if range.end.row < snapshot.max_row().0 {
2830                peek_end = Point::new(range.end.row + 1, 0);
2831            };
2832            (range.start..peek_end, end_excerpt_id)
2833        });
2834        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2835    }
2836
2837    pub fn resize_excerpt(
2838        &mut self,
2839        id: ExcerptId,
2840        range: Range<text::Anchor>,
2841        cx: &mut Context<Self>,
2842    ) {
2843        self.sync(cx);
2844
2845        let mut snapshot = self.snapshot.borrow_mut();
2846        let locator = snapshot.excerpt_locator_for_id(id);
2847        let mut new_excerpts = SumTree::default();
2848        let mut cursor = snapshot
2849            .excerpts
2850            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2851        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2852
2853        let prefix = cursor.slice(&Some(locator), Bias::Left);
2854        new_excerpts.append(prefix, &());
2855
2856        let mut excerpt = cursor.item().unwrap().clone();
2857        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2858
2859        excerpt.range.context.start = range.start;
2860        excerpt.range.context.end = range.end;
2861        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2862
2863        excerpt.text_summary = excerpt
2864            .buffer
2865            .text_summary_for_range(excerpt.range.context.clone());
2866
2867        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2868        let old_start_offset = cursor.start().1;
2869        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2870        let edit = Edit {
2871            old: old_start_offset..old_start_offset + old_text_len,
2872            new: new_start_offset..new_start_offset + new_text_len,
2873        };
2874
2875        if let Some(last_edit) = edits.last_mut() {
2876            if last_edit.old.end == edit.old.start {
2877                last_edit.old.end = edit.old.end;
2878                last_edit.new.end = edit.new.end;
2879            } else {
2880                edits.push(edit);
2881            }
2882        } else {
2883            edits.push(edit);
2884        }
2885
2886        new_excerpts.push(excerpt, &());
2887
2888        cursor.next();
2889
2890        new_excerpts.append(cursor.suffix(), &());
2891
2892        drop(cursor);
2893        snapshot.excerpts = new_excerpts;
2894
2895        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2896        cx.emit(Event::Edited {
2897            singleton_buffer_edited: false,
2898            edited_buffer: None,
2899        });
2900        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2901        cx.notify();
2902    }
2903
2904    pub fn expand_excerpts(
2905        &mut self,
2906        ids: impl IntoIterator<Item = ExcerptId>,
2907        line_count: u32,
2908        direction: ExpandExcerptDirection,
2909        cx: &mut Context<Self>,
2910    ) {
2911        if line_count == 0 {
2912            return;
2913        }
2914        self.sync(cx);
2915        if !self.excerpts_by_path.is_empty() {
2916            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2917            return;
2918        }
2919        let mut snapshot = self.snapshot.borrow_mut();
2920
2921        let ids = ids.into_iter().collect::<Vec<_>>();
2922        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2923        let mut new_excerpts = SumTree::default();
2924        let mut cursor = snapshot
2925            .excerpts
2926            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
2927        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2928
2929        for locator in &locators {
2930            let prefix = cursor.slice(&Some(locator), Bias::Left);
2931            new_excerpts.append(prefix, &());
2932
2933            let mut excerpt = cursor.item().unwrap().clone();
2934            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2935
2936            let up_line_count = if direction.should_expand_up() {
2937                line_count
2938            } else {
2939                0
2940            };
2941
2942            let start_row = excerpt
2943                .range
2944                .context
2945                .start
2946                .to_point(&excerpt.buffer)
2947                .row
2948                .saturating_sub(up_line_count);
2949            let start_point = Point::new(start_row, 0);
2950            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2951
2952            let down_line_count = if direction.should_expand_down() {
2953                line_count
2954            } else {
2955                0
2956            };
2957
2958            let mut end_point = excerpt.buffer.clip_point(
2959                excerpt.range.context.end.to_point(&excerpt.buffer)
2960                    + Point::new(down_line_count, 0),
2961                Bias::Left,
2962            );
2963            end_point.column = excerpt.buffer.line_len(end_point.row);
2964            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2965            excerpt.max_buffer_row = end_point.row;
2966
2967            excerpt.text_summary = excerpt
2968                .buffer
2969                .text_summary_for_range(excerpt.range.context.clone());
2970
2971            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2972            let old_start_offset = cursor.start().1;
2973            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2974            let edit = Edit {
2975                old: old_start_offset..old_start_offset + old_text_len,
2976                new: new_start_offset..new_start_offset + new_text_len,
2977            };
2978
2979            if let Some(last_edit) = edits.last_mut() {
2980                if last_edit.old.end == edit.old.start {
2981                    last_edit.old.end = edit.old.end;
2982                    last_edit.new.end = edit.new.end;
2983                } else {
2984                    edits.push(edit);
2985                }
2986            } else {
2987                edits.push(edit);
2988            }
2989
2990            new_excerpts.push(excerpt, &());
2991
2992            cursor.next();
2993        }
2994
2995        new_excerpts.append(cursor.suffix(), &());
2996
2997        drop(cursor);
2998        snapshot.excerpts = new_excerpts;
2999
3000        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3001        cx.emit(Event::Edited {
3002            singleton_buffer_edited: false,
3003            edited_buffer: None,
3004        });
3005        cx.emit(Event::ExcerptsExpanded { ids });
3006        cx.notify();
3007    }
3008
3009    fn sync(&self, cx: &App) {
3010        let changed = self.buffer_changed_since_sync.replace(false);
3011        if !changed {
3012            return;
3013        }
3014
3015        let mut snapshot = self.snapshot.borrow_mut();
3016        let mut excerpts_to_edit = Vec::new();
3017        let mut non_text_state_updated = false;
3018        let mut is_dirty = false;
3019        let mut has_deleted_file = false;
3020        let mut has_conflict = false;
3021        let mut edited = false;
3022        let mut buffers = self.buffers.borrow_mut();
3023        for buffer_state in buffers.values_mut() {
3024            let buffer = buffer_state.buffer.read(cx);
3025            let version = buffer.version();
3026            let non_text_state_update_count = buffer.non_text_state_update_count();
3027
3028            let buffer_edited = version.changed_since(&buffer_state.last_version);
3029            let buffer_non_text_state_updated =
3030                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
3031            if buffer_edited || buffer_non_text_state_updated {
3032                buffer_state.last_version = version;
3033                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
3034                excerpts_to_edit.extend(
3035                    buffer_state
3036                        .excerpts
3037                        .iter()
3038                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
3039                );
3040            }
3041
3042            edited |= buffer_edited;
3043            non_text_state_updated |= buffer_non_text_state_updated;
3044            is_dirty |= buffer.is_dirty();
3045            has_deleted_file |= buffer
3046                .file()
3047                .is_some_and(|file| file.disk_state() == DiskState::Deleted);
3048            has_conflict |= buffer.has_conflict();
3049        }
3050        if edited {
3051            snapshot.edit_count += 1;
3052        }
3053        if non_text_state_updated {
3054            snapshot.non_text_state_update_count += 1;
3055        }
3056        snapshot.is_dirty = is_dirty;
3057        snapshot.has_deleted_file = has_deleted_file;
3058        snapshot.has_conflict = has_conflict;
3059
3060        for (id, diff) in self.diffs.iter() {
3061            if snapshot.diffs.get(id).is_none() {
3062                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
3063            }
3064        }
3065
3066        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3067
3068        let mut edits = Vec::new();
3069        let mut new_excerpts = SumTree::default();
3070        let mut cursor = snapshot
3071            .excerpts
3072            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
3073
3074        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3075            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left), &());
3076            let old_excerpt = cursor.item().unwrap();
3077            let buffer = buffer.read(cx);
3078            let buffer_id = buffer.remote_id();
3079
3080            let mut new_excerpt;
3081            if buffer_edited {
3082                edits.extend(
3083                    buffer
3084                        .edits_since_in_range::<usize>(
3085                            old_excerpt.buffer.version(),
3086                            old_excerpt.range.context.clone(),
3087                        )
3088                        .map(|edit| {
3089                            let excerpt_old_start = cursor.start().1;
3090                            let excerpt_new_start =
3091                                ExcerptOffset::new(new_excerpts.summary().text.len);
3092                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3093                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3094                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3095                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3096                            Edit {
3097                                old: old_start..old_end,
3098                                new: new_start..new_end,
3099                            }
3100                        }),
3101                );
3102
3103                new_excerpt = Excerpt::new(
3104                    old_excerpt.id,
3105                    locator.clone(),
3106                    buffer_id,
3107                    buffer.snapshot(),
3108                    old_excerpt.range.clone(),
3109                    old_excerpt.has_trailing_newline,
3110                );
3111            } else {
3112                new_excerpt = old_excerpt.clone();
3113                new_excerpt.buffer = buffer.snapshot();
3114            }
3115
3116            new_excerpts.push(new_excerpt, &());
3117            cursor.next();
3118        }
3119        new_excerpts.append(cursor.suffix(), &());
3120
3121        drop(cursor);
3122        snapshot.excerpts = new_excerpts;
3123
3124        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3125    }
3126
3127    fn sync_diff_transforms(
3128        &self,
3129        snapshot: &mut MultiBufferSnapshot,
3130        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3131        change_kind: DiffChangeKind,
3132    ) {
3133        if excerpt_edits.is_empty() {
3134            return;
3135        }
3136
3137        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3138        let mut old_diff_transforms = snapshot
3139            .diff_transforms
3140            .cursor::<Dimensions<ExcerptOffset, usize>>(&());
3141        let mut new_diff_transforms = SumTree::default();
3142        let mut old_expanded_hunks = HashSet::default();
3143        let mut output_edits = Vec::new();
3144        let mut output_delta = 0_isize;
3145        let mut at_transform_boundary = true;
3146        let mut end_of_current_insert = None;
3147
3148        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3149        while let Some(edit) = excerpt_edits.next() {
3150            excerpts.seek_forward(&edit.new.start, Bias::Right);
3151            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3152                excerpts.prev();
3153            }
3154
3155            // Keep any transforms that are before the edit.
3156            if at_transform_boundary {
3157                at_transform_boundary = false;
3158                let transforms_before_edit = old_diff_transforms.slice(&edit.old.start, Bias::Left);
3159                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3160                if let Some(transform) = old_diff_transforms.item()
3161                    && old_diff_transforms.end().0 == edit.old.start
3162                    && old_diff_transforms.start().0 < edit.old.start
3163                {
3164                    self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3165                    old_diff_transforms.next();
3166                }
3167            }
3168
3169            // Compute the start of the edit in output coordinates.
3170            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3171            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3172            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3173
3174            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3175                &edit,
3176                &mut excerpts,
3177                &mut old_diff_transforms,
3178                &mut new_diff_transforms,
3179                &mut end_of_current_insert,
3180                &mut old_expanded_hunks,
3181                snapshot,
3182                change_kind,
3183            );
3184
3185            // Compute the end of the edit in output coordinates.
3186            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3187            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3188            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3189            let edit_new_end =
3190                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3191            let output_edit = Edit {
3192                old: edit_old_start..edit_old_end,
3193                new: edit_new_start..edit_new_end,
3194            };
3195
3196            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3197            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3198            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3199                output_edits.push(output_edit);
3200            }
3201
3202            // If this is the last edit that intersects the current diff transform,
3203            // then recreate the content up to the end of this transform, to prepare
3204            // for reusing additional slices of the old transforms.
3205            if excerpt_edits
3206                .peek()
3207                .is_none_or(|next_edit| next_edit.old.start >= old_diff_transforms.end().0)
3208            {
3209                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3210                    && match old_diff_transforms.item() {
3211                        Some(DiffTransform::BufferContent {
3212                            inserted_hunk_info: Some(hunk),
3213                            ..
3214                        }) => excerpts.item().is_some_and(|excerpt| {
3215                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3216                        }),
3217                        _ => true,
3218                    };
3219
3220                let mut excerpt_offset = edit.new.end;
3221                if !keep_next_old_transform {
3222                    excerpt_offset += old_diff_transforms.end().0 - edit.old.end;
3223                    old_diff_transforms.next();
3224                }
3225
3226                old_expanded_hunks.clear();
3227                self.push_buffer_content_transform(
3228                    snapshot,
3229                    &mut new_diff_transforms,
3230                    excerpt_offset,
3231                    end_of_current_insert,
3232                );
3233                at_transform_boundary = true;
3234            }
3235        }
3236
3237        // Keep any transforms that are after the last edit.
3238        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix());
3239
3240        // Ensure there's always at least one buffer content transform.
3241        if new_diff_transforms.is_empty() {
3242            new_diff_transforms.push(
3243                DiffTransform::BufferContent {
3244                    summary: Default::default(),
3245                    inserted_hunk_info: None,
3246                },
3247                &(),
3248            );
3249        }
3250
3251        self.subscriptions.publish(output_edits);
3252        drop(old_diff_transforms);
3253        drop(excerpts);
3254        snapshot.diff_transforms = new_diff_transforms;
3255        snapshot.edit_count += 1;
3256
3257        #[cfg(any(test, feature = "test-support"))]
3258        snapshot.check_invariants();
3259    }
3260
3261    fn recompute_diff_transforms_for_edit(
3262        &self,
3263        edit: &Edit<TypedOffset<Excerpt>>,
3264        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3265        old_diff_transforms: &mut Cursor<DiffTransform, Dimensions<TypedOffset<Excerpt>, usize>>,
3266        new_diff_transforms: &mut SumTree<DiffTransform>,
3267        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3268        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3269        snapshot: &MultiBufferSnapshot,
3270        change_kind: DiffChangeKind,
3271    ) -> bool {
3272        log::trace!(
3273            "recomputing diff transform for edit {:?} => {:?}",
3274            edit.old.start.value..edit.old.end.value,
3275            edit.new.start.value..edit.new.end.value
3276        );
3277
3278        // Record which hunks were previously expanded.
3279        while let Some(item) = old_diff_transforms.item() {
3280            if let Some(hunk_info) = item.hunk_info() {
3281                log::trace!(
3282                    "previously expanded hunk at {}",
3283                    old_diff_transforms.start().0
3284                );
3285                old_expanded_hunks.insert(hunk_info);
3286            }
3287            if old_diff_transforms.end().0 > edit.old.end {
3288                break;
3289            }
3290            old_diff_transforms.next();
3291        }
3292
3293        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3294        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3295        if old_expanded_hunks.is_empty()
3296            && change_kind == DiffChangeKind::BufferEdited
3297            && !all_diff_hunks_expanded
3298        {
3299            return false;
3300        }
3301
3302        // Visit each excerpt that intersects the edit.
3303        let mut did_expand_hunks = false;
3304        while let Some(excerpt) = excerpts.item() {
3305            // Recompute the expanded hunks in the portion of the excerpt that
3306            // intersects the edit.
3307            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3308                let buffer = &excerpt.buffer;
3309                let excerpt_start = *excerpts.start();
3310                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3311                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3312                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3313                let edit_buffer_start =
3314                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3315                let edit_buffer_end =
3316                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3317                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3318                let edit_anchor_range =
3319                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3320
3321                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3322                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3323                        continue;
3324                    }
3325
3326                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3327                    if hunk_buffer_range.start < excerpt_buffer_start {
3328                        log::trace!("skipping hunk that starts before excerpt");
3329                        continue;
3330                    }
3331
3332                    let hunk_info = DiffTransformHunkInfo {
3333                        excerpt_id: excerpt.id,
3334                        hunk_start_anchor: hunk.buffer_range.start,
3335                        hunk_secondary_status: hunk.secondary_status,
3336                    };
3337
3338                    let hunk_excerpt_start = excerpt_start
3339                        + ExcerptOffset::new(
3340                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3341                        );
3342                    let hunk_excerpt_end = excerpt_end.min(
3343                        excerpt_start
3344                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3345                    );
3346
3347                    self.push_buffer_content_transform(
3348                        snapshot,
3349                        new_diff_transforms,
3350                        hunk_excerpt_start,
3351                        *end_of_current_insert,
3352                    );
3353
3354                    // For every existing hunk, determine if it was previously expanded
3355                    // and if it should currently be expanded.
3356                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3357                    let should_expand_hunk = match &change_kind {
3358                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3359                            was_previously_expanded || all_diff_hunks_expanded
3360                        }
3361                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3362                            let intersects = hunk_buffer_range.is_empty()
3363                                || hunk_buffer_range.end > edit_buffer_start;
3364                            if *expand {
3365                                intersects || was_previously_expanded || all_diff_hunks_expanded
3366                            } else {
3367                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3368                            }
3369                        }
3370                        _ => was_previously_expanded || all_diff_hunks_expanded,
3371                    };
3372
3373                    if should_expand_hunk {
3374                        did_expand_hunks = true;
3375                        log::trace!(
3376                            "expanding hunk {:?}, excerpt:{:?}",
3377                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3378                            excerpt.id
3379                        );
3380
3381                        if !hunk.diff_base_byte_range.is_empty()
3382                            && hunk_buffer_range.start >= edit_buffer_start
3383                            && hunk_buffer_range.start <= excerpt_buffer_end
3384                        {
3385                            let base_text = diff.base_text();
3386                            let mut text_cursor =
3387                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3388                            let mut base_text_summary =
3389                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3390
3391                            let mut has_trailing_newline = false;
3392                            if base_text_summary.last_line_chars > 0 {
3393                                base_text_summary += TextSummary::newline();
3394                                has_trailing_newline = true;
3395                            }
3396
3397                            new_diff_transforms.push(
3398                                DiffTransform::DeletedHunk {
3399                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3400                                    summary: base_text_summary,
3401                                    buffer_id: excerpt.buffer_id,
3402                                    hunk_info,
3403                                    has_trailing_newline,
3404                                },
3405                                &(),
3406                            );
3407                        }
3408
3409                        if !hunk_buffer_range.is_empty() {
3410                            *end_of_current_insert =
3411                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3412                        }
3413                    }
3414                }
3415            }
3416
3417            if excerpts.end() <= edit.new.end {
3418                excerpts.next();
3419            } else {
3420                break;
3421            }
3422        }
3423
3424        did_expand_hunks || !old_expanded_hunks.is_empty()
3425    }
3426
3427    fn append_diff_transforms(
3428        &self,
3429        new_transforms: &mut SumTree<DiffTransform>,
3430        subtree: SumTree<DiffTransform>,
3431    ) {
3432        if let Some(DiffTransform::BufferContent {
3433            inserted_hunk_info,
3434            summary,
3435        }) = subtree.first()
3436            && self.extend_last_buffer_content_transform(
3437                new_transforms,
3438                *inserted_hunk_info,
3439                *summary,
3440            )
3441        {
3442            let mut cursor = subtree.cursor::<()>(&());
3443            cursor.next();
3444            cursor.next();
3445            new_transforms.append(cursor.suffix(), &());
3446            return;
3447        }
3448        new_transforms.append(subtree, &());
3449    }
3450
3451    fn push_diff_transform(
3452        &self,
3453        new_transforms: &mut SumTree<DiffTransform>,
3454        transform: DiffTransform,
3455    ) {
3456        if let DiffTransform::BufferContent {
3457            inserted_hunk_info: inserted_hunk_anchor,
3458            summary,
3459        } = transform
3460            && self.extend_last_buffer_content_transform(
3461                new_transforms,
3462                inserted_hunk_anchor,
3463                summary,
3464            )
3465        {
3466            return;
3467        }
3468        new_transforms.push(transform, &());
3469    }
3470
3471    fn push_buffer_content_transform(
3472        &self,
3473        old_snapshot: &MultiBufferSnapshot,
3474        new_transforms: &mut SumTree<DiffTransform>,
3475        end_offset: ExcerptOffset,
3476        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3477    ) {
3478        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3479            (end_offset.min(insertion_end_offset), Some(hunk_info))
3480        });
3481        let unchanged_region = [(end_offset, None)];
3482
3483        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3484        {
3485            let start_offset = new_transforms.summary().excerpt_len();
3486            if end_offset <= start_offset {
3487                continue;
3488            }
3489            let summary_to_add = old_snapshot
3490                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3491
3492            if !self.extend_last_buffer_content_transform(
3493                new_transforms,
3494                inserted_hunk_info,
3495                summary_to_add,
3496            ) {
3497                new_transforms.push(
3498                    DiffTransform::BufferContent {
3499                        summary: summary_to_add,
3500                        inserted_hunk_info,
3501                    },
3502                    &(),
3503                )
3504            }
3505        }
3506    }
3507
3508    fn extend_last_buffer_content_transform(
3509        &self,
3510        new_transforms: &mut SumTree<DiffTransform>,
3511        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3512        summary_to_add: TextSummary,
3513    ) -> bool {
3514        let mut did_extend = false;
3515        new_transforms.update_last(
3516            |last_transform| {
3517                if let DiffTransform::BufferContent {
3518                    summary,
3519                    inserted_hunk_info: inserted_hunk_anchor,
3520                } = last_transform
3521                    && *inserted_hunk_anchor == new_inserted_hunk_info
3522                {
3523                    *summary += summary_to_add;
3524                    did_extend = true;
3525                }
3526            },
3527            &(),
3528        );
3529        did_extend
3530    }
3531}
3532
3533fn build_excerpt_ranges(
3534    ranges: impl IntoIterator<Item = Range<Point>>,
3535    context_line_count: u32,
3536    buffer_snapshot: &BufferSnapshot,
3537) -> Vec<ExcerptRange<Point>> {
3538    ranges
3539        .into_iter()
3540        .map(|range| {
3541            let start_row = range.start.row.saturating_sub(context_line_count);
3542            let start = Point::new(start_row, 0);
3543            let end_row = (range.end.row + context_line_count).min(buffer_snapshot.max_point().row);
3544            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
3545            ExcerptRange {
3546                context: start..end,
3547                primary: range,
3548            }
3549        })
3550        .collect()
3551}
3552
3553#[cfg(any(test, feature = "test-support"))]
3554impl MultiBuffer {
3555    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3556        let buffer = cx.new(|cx| Buffer::local(text, cx));
3557        cx.new(|cx| Self::singleton(buffer, cx))
3558    }
3559
3560    pub fn build_multi<const COUNT: usize>(
3561        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3562        cx: &mut gpui::App,
3563    ) -> Entity<Self> {
3564        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3565        for (text, ranges) in excerpts {
3566            let buffer = cx.new(|cx| Buffer::local(text, cx));
3567            let excerpt_ranges = ranges.into_iter().map(ExcerptRange::new);
3568            multi.update(cx, |multi, cx| {
3569                multi.push_excerpts(buffer, excerpt_ranges, cx)
3570            });
3571        }
3572
3573        multi
3574    }
3575
3576    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3577        cx.new(|cx| Self::singleton(buffer, cx))
3578    }
3579
3580    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3581        cx.new(|cx| {
3582            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3583            let mutation_count = rng.gen_range(1..=5);
3584            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3585            multibuffer
3586        })
3587    }
3588
3589    pub fn randomly_edit(
3590        &mut self,
3591        rng: &mut impl rand::Rng,
3592        edit_count: usize,
3593        cx: &mut Context<Self>,
3594    ) {
3595        use util::RandomCharIter;
3596
3597        let snapshot = self.read(cx);
3598        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3599        let mut last_end = None;
3600        for _ in 0..edit_count {
3601            if last_end.is_some_and(|last_end| last_end >= snapshot.len()) {
3602                break;
3603            }
3604
3605            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3606            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3607            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3608            last_end = Some(end);
3609
3610            let mut range = start..end;
3611            if rng.gen_bool(0.2) {
3612                mem::swap(&mut range.start, &mut range.end);
3613            }
3614
3615            let new_text_len = rng.gen_range(0..10);
3616            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3617
3618            edits.push((range, new_text.into()));
3619        }
3620        log::info!("mutating multi-buffer with {:?}", edits);
3621        drop(snapshot);
3622
3623        self.edit(edits, None, cx);
3624    }
3625
3626    pub fn randomly_edit_excerpts(
3627        &mut self,
3628        rng: &mut impl rand::Rng,
3629        mutation_count: usize,
3630        cx: &mut Context<Self>,
3631    ) {
3632        use rand::prelude::*;
3633        use std::env;
3634        use util::RandomCharIter;
3635
3636        let max_excerpts = env::var("MAX_EXCERPTS")
3637            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3638            .unwrap_or(5);
3639
3640        let mut buffers = Vec::new();
3641        for _ in 0..mutation_count {
3642            if rng.gen_bool(0.05) {
3643                log::info!("Clearing multi-buffer");
3644                self.clear(cx);
3645                continue;
3646            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3647                let ids = self.excerpt_ids();
3648                let mut excerpts = HashSet::default();
3649                for _ in 0..rng.gen_range(0..ids.len()) {
3650                    excerpts.extend(ids.choose(rng).copied());
3651                }
3652
3653                let line_count = rng.gen_range(0..5);
3654
3655                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3656
3657                self.expand_excerpts(
3658                    excerpts.iter().cloned(),
3659                    line_count,
3660                    ExpandExcerptDirection::UpAndDown,
3661                    cx,
3662                );
3663                continue;
3664            }
3665
3666            let excerpt_ids = self.excerpt_ids();
3667            if excerpt_ids.is_empty() || (rng.r#gen() && excerpt_ids.len() < max_excerpts) {
3668                let buffer_handle = if rng.r#gen() || self.buffers.borrow().is_empty() {
3669                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3670                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3671                    let buffer = buffers.last().unwrap().read(cx);
3672                    log::info!(
3673                        "Creating new buffer {} with text: {:?}",
3674                        buffer.remote_id(),
3675                        buffer.text()
3676                    );
3677                    buffers.last().unwrap().clone()
3678                } else {
3679                    self.buffers
3680                        .borrow()
3681                        .values()
3682                        .choose(rng)
3683                        .unwrap()
3684                        .buffer
3685                        .clone()
3686                };
3687
3688                let buffer = buffer_handle.read(cx);
3689                let buffer_text = buffer.text();
3690                let ranges = (0..rng.gen_range(0..5))
3691                    .map(|_| {
3692                        let end_ix =
3693                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3694                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3695                        ExcerptRange::new(start_ix..end_ix)
3696                    })
3697                    .collect::<Vec<_>>();
3698                log::info!(
3699                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3700                    buffer_handle.read(cx).remote_id(),
3701                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3702                    ranges
3703                        .iter()
3704                        .map(|r| &buffer_text[r.context.clone()])
3705                        .collect::<Vec<_>>()
3706                );
3707
3708                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3709                log::info!("Inserted with ids: {:?}", excerpt_id);
3710            } else {
3711                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3712                let mut excerpts_to_remove = excerpt_ids
3713                    .choose_multiple(rng, remove_count)
3714                    .cloned()
3715                    .collect::<Vec<_>>();
3716                let snapshot = self.snapshot.borrow();
3717                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3718                drop(snapshot);
3719                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3720                self.remove_excerpts(excerpts_to_remove, cx);
3721            }
3722        }
3723    }
3724
3725    pub fn randomly_mutate(
3726        &mut self,
3727        rng: &mut impl rand::Rng,
3728        mutation_count: usize,
3729        cx: &mut Context<Self>,
3730    ) {
3731        use rand::prelude::*;
3732
3733        if rng.gen_bool(0.7) || self.singleton {
3734            let buffer = self
3735                .buffers
3736                .borrow()
3737                .values()
3738                .choose(rng)
3739                .map(|state| state.buffer.clone());
3740
3741            if let Some(buffer) = buffer {
3742                buffer.update(cx, |buffer, cx| {
3743                    if rng.r#gen() {
3744                        buffer.randomly_edit(rng, mutation_count, cx);
3745                    } else {
3746                        buffer.randomly_undo_redo(rng, cx);
3747                    }
3748                });
3749            } else {
3750                self.randomly_edit(rng, mutation_count, cx);
3751            }
3752        } else {
3753            self.randomly_edit_excerpts(rng, mutation_count, cx);
3754        }
3755
3756        self.check_invariants(cx);
3757    }
3758
3759    fn check_invariants(&self, cx: &App) {
3760        self.read(cx).check_invariants();
3761    }
3762}
3763
3764impl EventEmitter<Event> for MultiBuffer {}
3765
3766impl MultiBufferSnapshot {
3767    pub fn text(&self) -> String {
3768        self.chunks(0..self.len(), false)
3769            .map(|chunk| chunk.text)
3770            .collect()
3771    }
3772
3773    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3774        self.reversed_chunks_in_range(0..position.to_offset(self))
3775            .flat_map(|c| c.chars().rev())
3776    }
3777
3778    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks<'_> {
3779        let mut cursor = self.cursor::<usize>();
3780        cursor.seek(&range.end);
3781        let current_chunks = cursor.region().as_ref().map(|region| {
3782            let start_overshoot = range.start.saturating_sub(region.range.start);
3783            let end_overshoot = range.end - region.range.start;
3784            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3785            let start = region.buffer_range.start + start_overshoot;
3786            region.buffer.reversed_chunks_in_range(start..end)
3787        });
3788        ReversedMultiBufferChunks {
3789            cursor,
3790            current_chunks,
3791            start: range.start,
3792            offset: range.end,
3793        }
3794    }
3795
3796    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3797        let offset = position.to_offset(self);
3798        self.text_for_range(offset..self.len())
3799            .flat_map(|chunk| chunk.chars())
3800    }
3801
3802    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3803        self.chunks(range, false).map(|chunk| chunk.text)
3804    }
3805
3806    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3807        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3808            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3809    }
3810
3811    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3812    where
3813        T: ToOffset,
3814    {
3815        let position = position.to_offset(self);
3816        position == self.clip_offset(position, Bias::Left)
3817            && self
3818                .bytes_in_range(position..self.len())
3819                .flatten()
3820                .copied()
3821                .take(needle.len())
3822                .eq(needle.bytes())
3823    }
3824
3825    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3826        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3827    }
3828
3829    pub fn diff_hunks_in_range<T: ToPoint>(
3830        &self,
3831        range: Range<T>,
3832    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3833        let query_range = range.start.to_point(self)..range.end.to_point(self);
3834        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3835            let diff = self.diffs.get(&buffer.remote_id())?;
3836            let buffer_start = buffer.anchor_before(buffer_range.start);
3837            let buffer_end = buffer.anchor_after(buffer_range.end);
3838            Some(
3839                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3840                    .filter_map(|hunk| {
3841                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3842                            return None;
3843                        }
3844                        Some((hunk.range.clone(), hunk))
3845                    }),
3846            )
3847        })
3848        .filter_map(move |(range, hunk, excerpt)| {
3849            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3850            {
3851                return None;
3852            }
3853            let end_row = if range.end.column == 0 {
3854                range.end.row
3855            } else {
3856                range.end.row + 1
3857            };
3858            Some(MultiBufferDiffHunk {
3859                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3860                buffer_id: excerpt.buffer_id,
3861                excerpt_id: excerpt.id,
3862                buffer_range: hunk.buffer_range.clone(),
3863                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3864                secondary_status: hunk.secondary_status,
3865            })
3866        })
3867    }
3868
3869    pub fn excerpt_ids_for_range<T: ToOffset>(
3870        &self,
3871        range: Range<T>,
3872    ) -> impl Iterator<Item = ExcerptId> + '_ {
3873        let range = range.start.to_offset(self)..range.end.to_offset(self);
3874        let mut cursor = self.cursor::<usize>();
3875        cursor.seek(&range.start);
3876        std::iter::from_fn(move || {
3877            let region = cursor.region()?;
3878            if region.range.start >= range.end {
3879                return None;
3880            }
3881            cursor.next_excerpt();
3882            Some(region.excerpt.id)
3883        })
3884    }
3885
3886    pub fn buffer_ids_for_range<T: ToOffset>(
3887        &self,
3888        range: Range<T>,
3889    ) -> impl Iterator<Item = BufferId> + '_ {
3890        let range = range.start.to_offset(self)..range.end.to_offset(self);
3891        let mut cursor = self.cursor::<usize>();
3892        cursor.seek(&range.start);
3893        std::iter::from_fn(move || {
3894            let region = cursor.region()?;
3895            if region.range.start > range.end
3896                || region.range.start == range.end && region.range.start > range.start
3897            {
3898                return None;
3899            }
3900            cursor.next_excerpt();
3901            Some(region.excerpt.buffer_id)
3902        })
3903    }
3904
3905    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3906        &self,
3907        ranges: impl Iterator<Item = Range<T>>,
3908    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3909        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3910    }
3911
3912    pub fn range_to_buffer_ranges<T: ToOffset>(
3913        &self,
3914        range: Range<T>,
3915    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3916        let start = range.start.to_offset(self);
3917        let end = range.end.to_offset(self);
3918
3919        let mut cursor = self.cursor::<usize>();
3920        cursor.seek(&start);
3921
3922        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3923        while let Some(region) = cursor.region() {
3924            if region.range.start > end {
3925                break;
3926            }
3927            if region.is_main_buffer {
3928                let start_overshoot = start.saturating_sub(region.range.start);
3929                let end_overshoot = end.saturating_sub(region.range.start);
3930                let start = region
3931                    .buffer_range
3932                    .end
3933                    .min(region.buffer_range.start + start_overshoot);
3934                let end = region
3935                    .buffer_range
3936                    .end
3937                    .min(region.buffer_range.start + end_overshoot);
3938                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3939                    *excerpt_id == region.excerpt.id && prev_range.end == start
3940                }) {
3941                    prev.1.end = end;
3942                } else {
3943                    result.push((region.buffer, start..end, region.excerpt.id));
3944                }
3945            }
3946            cursor.next();
3947        }
3948        result
3949    }
3950
3951    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3952        &self,
3953        range: Range<T>,
3954    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3955        let start = range.start.to_offset(self);
3956        let end = range.end.to_offset(self);
3957
3958        let mut cursor = self.cursor::<usize>();
3959        cursor.seek(&start);
3960
3961        std::iter::from_fn(move || {
3962            let region = cursor.region()?;
3963            if region.range.start > end {
3964                return None;
3965            }
3966            let start_overshoot = start.saturating_sub(region.range.start);
3967            let end_overshoot = end.saturating_sub(region.range.start);
3968            let start = region
3969                .buffer_range
3970                .end
3971                .min(region.buffer_range.start + start_overshoot);
3972            let end = region
3973                .buffer_range
3974                .end
3975                .min(region.buffer_range.start + end_overshoot);
3976
3977            let region_excerpt_id = region.excerpt.id;
3978            let deleted_hunk_anchor = if region.is_main_buffer {
3979                None
3980            } else {
3981                Some(self.anchor_before(region.range.start))
3982            };
3983            let result = (
3984                region.buffer,
3985                start..end,
3986                region_excerpt_id,
3987                deleted_hunk_anchor,
3988            );
3989            cursor.next();
3990            Some(result)
3991        })
3992    }
3993
3994    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3995    /// coordinates.
3996    ///
3997    /// The given callback will be called for every excerpt intersecting the given range. It will
3998    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3999    /// The callback should return an iterator of metadata items from that buffer, each paired
4000    /// with a buffer range.
4001    ///
4002    /// The returned iterator yields each of these metadata items, paired with its range in
4003    /// multi-buffer coordinates.
4004    fn lift_buffer_metadata<'a, D, M, I>(
4005        &'a self,
4006        query_range: Range<D>,
4007        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
4008    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
4009    where
4010        I: Iterator<Item = (Range<D>, M)> + 'a,
4011        D: TextDimension + Ord + Sub<D, Output = D>,
4012    {
4013        let max_position = D::from_text_summary(&self.text_summary());
4014        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
4015        let mut cursor = self.cursor::<D>();
4016
4017        // Find the excerpt and buffer offset where the given range ends.
4018        cursor.seek(&query_range.end);
4019        let mut range_end = None;
4020        while let Some(region) = cursor.region() {
4021            if region.is_main_buffer {
4022                let mut buffer_end = region.buffer_range.start;
4023                let overshoot = if query_range.end > region.range.start {
4024                    query_range.end - region.range.start
4025                } else {
4026                    D::default()
4027                };
4028                buffer_end.add_assign(&overshoot);
4029                range_end = Some((region.excerpt.id, buffer_end));
4030                break;
4031            }
4032            cursor.next();
4033        }
4034
4035        cursor.seek(&query_range.start);
4036
4037        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer)
4038            && region.range.start > D::zero(&())
4039        {
4040            cursor.prev()
4041        }
4042
4043        iter::from_fn(move || {
4044            loop {
4045                let excerpt = cursor.excerpt()?;
4046
4047                // If we have already retrieved metadata for this excerpt, continue to use it.
4048                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
4049                    .as_mut()
4050                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
4051                {
4052                    Some(metadata)
4053                }
4054                // Otherwise, compute the intersection of the input range with the excerpt's range,
4055                // and retrieve the metadata for the resulting range.
4056                else {
4057                    let region = cursor.region()?;
4058                    let mut buffer_start;
4059                    if region.is_main_buffer {
4060                        buffer_start = region.buffer_range.start;
4061                        if query_range.start > region.range.start {
4062                            let overshoot = query_range.start - region.range.start;
4063                            buffer_start.add_assign(&overshoot);
4064                        }
4065                        buffer_start = buffer_start.min(region.buffer_range.end);
4066                    } else {
4067                        buffer_start = cursor.main_buffer_position()?;
4068                    };
4069                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4070                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end
4071                        && excerpt.id == end_excerpt_id
4072                    {
4073                        buffer_end = buffer_end.min(end_buffer_offset);
4074                    }
4075
4076                    get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end).map(|iterator| {
4077                        &mut current_excerpt_metadata.insert((excerpt.id, iterator)).1
4078                    })
4079                };
4080
4081                // Visit each metadata item.
4082                if let Some((metadata_buffer_range, metadata)) =
4083                    metadata_iter.and_then(Iterator::next)
4084                {
4085                    // Find the multibuffer regions that contain the start and end of
4086                    // the metadata item's range.
4087                    if metadata_buffer_range.start > D::default() {
4088                        while let Some(region) = cursor.region() {
4089                            if region.is_main_buffer
4090                                && (region.buffer_range.end >= metadata_buffer_range.start
4091                                    || cursor.is_at_end_of_excerpt())
4092                            {
4093                                break;
4094                            }
4095                            cursor.next();
4096                        }
4097                    }
4098                    let start_region = cursor.region()?;
4099                    while let Some(region) = cursor.region() {
4100                        if region.is_main_buffer
4101                            && (region.buffer_range.end > metadata_buffer_range.end
4102                                || cursor.is_at_end_of_excerpt())
4103                        {
4104                            break;
4105                        }
4106                        cursor.next();
4107                    }
4108                    let end_region = cursor.region();
4109
4110                    // Convert the metadata item's range into multibuffer coordinates.
4111                    let mut start_position = start_region.range.start;
4112                    let region_buffer_start = start_region.buffer_range.start;
4113                    if start_region.is_main_buffer
4114                        && metadata_buffer_range.start > region_buffer_start
4115                    {
4116                        start_position
4117                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4118                        start_position = start_position.min(start_region.range.end);
4119                    }
4120
4121                    let mut end_position = max_position;
4122                    if let Some(end_region) = &end_region {
4123                        end_position = end_region.range.start;
4124                        debug_assert!(end_region.is_main_buffer);
4125                        let region_buffer_start = end_region.buffer_range.start;
4126                        if metadata_buffer_range.end > region_buffer_start {
4127                            end_position
4128                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4129                        }
4130                        end_position = end_position.min(end_region.range.end);
4131                    }
4132
4133                    if start_position <= query_range.end && end_position >= query_range.start {
4134                        return Some((start_position..end_position, metadata, excerpt));
4135                    }
4136                }
4137                // When there are no more metadata items for this excerpt, move to the next excerpt.
4138                else {
4139                    current_excerpt_metadata.take();
4140                    if let Some((end_excerpt_id, _)) = range_end
4141                        && excerpt.id == end_excerpt_id
4142                    {
4143                        return None;
4144                    }
4145                    cursor.next_excerpt();
4146                }
4147            }
4148        })
4149    }
4150
4151    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4152        let offset = position.to_offset(self);
4153
4154        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4155        cursor.seek(&DimensionPair {
4156            key: offset,
4157            value: None,
4158        });
4159        cursor.seek_to_start_of_current_excerpt();
4160        let excerpt = cursor.excerpt()?;
4161
4162        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4163        let current_position = self
4164            .anchor_before(offset)
4165            .text_anchor
4166            .to_offset(&excerpt.buffer);
4167        let excerpt_end = excerpt
4168            .buffer
4169            .anchor_before(excerpt_end.min(current_position));
4170
4171        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4172            for hunk in diff.hunks_intersecting_range_rev(
4173                excerpt.range.context.start..excerpt_end,
4174                &excerpt.buffer,
4175            ) {
4176                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4177                if hunk_end >= current_position {
4178                    continue;
4179                }
4180                let start =
4181                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4182                        .to_point(self);
4183                return Some(MultiBufferRow(start.row));
4184            }
4185        }
4186
4187        loop {
4188            cursor.prev_excerpt();
4189            let excerpt = cursor.excerpt()?;
4190
4191            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4192                continue;
4193            };
4194            let mut hunks =
4195                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4196            let Some(hunk) = hunks.next() else {
4197                continue;
4198            };
4199            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4200                .to_point(self);
4201            return Some(MultiBufferRow(start.row));
4202        }
4203    }
4204
4205    pub fn has_diff_hunks(&self) -> bool {
4206        self.diffs.values().any(|diff| !diff.is_empty())
4207    }
4208
4209    pub fn is_inside_word<T: ToOffset>(&self, position: T, for_completion: bool) -> bool {
4210        let position = position.to_offset(self);
4211        let classifier = self
4212            .char_classifier_at(position)
4213            .for_completion(for_completion);
4214        let next_char_kind = self.chars_at(position).next().map(|c| classifier.kind(c));
4215        let prev_char_kind = self
4216            .reversed_chars_at(position)
4217            .next()
4218            .map(|c| classifier.kind(c));
4219        prev_char_kind.zip(next_char_kind) == Some((CharKind::Word, CharKind::Word))
4220    }
4221
4222    pub fn surrounding_word<T: ToOffset>(
4223        &self,
4224        start: T,
4225        for_completion: bool,
4226    ) -> (Range<usize>, Option<CharKind>) {
4227        let mut start = start.to_offset(self);
4228        let mut end = start;
4229        let mut next_chars = self.chars_at(start).peekable();
4230        let mut prev_chars = self.reversed_chars_at(start).peekable();
4231
4232        let classifier = self
4233            .char_classifier_at(start)
4234            .for_completion(for_completion);
4235
4236        let word_kind = cmp::max(
4237            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4238            next_chars.peek().copied().map(|c| classifier.kind(c)),
4239        );
4240
4241        for ch in prev_chars {
4242            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4243                start -= ch.len_utf8();
4244            } else {
4245                break;
4246            }
4247        }
4248
4249        for ch in next_chars {
4250            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4251                end += ch.len_utf8();
4252            } else {
4253                break;
4254            }
4255        }
4256
4257        (start..end, word_kind)
4258    }
4259
4260    pub fn char_kind_before<T: ToOffset>(
4261        &self,
4262        start: T,
4263        for_completion: bool,
4264    ) -> Option<CharKind> {
4265        let start = start.to_offset(self);
4266        let classifier = self
4267            .char_classifier_at(start)
4268            .for_completion(for_completion);
4269        self.reversed_chars_at(start)
4270            .next()
4271            .map(|ch| classifier.kind(ch))
4272    }
4273
4274    pub fn is_singleton(&self) -> bool {
4275        self.singleton
4276    }
4277
4278    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4279        if self.singleton {
4280            self.excerpts
4281                .iter()
4282                .next()
4283                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4284        } else {
4285            None
4286        }
4287    }
4288
4289    pub fn len(&self) -> usize {
4290        self.diff_transforms.summary().output.len
4291    }
4292
4293    pub fn is_empty(&self) -> bool {
4294        self.excerpts.summary().text.len == 0
4295    }
4296
4297    pub fn widest_line_number(&self) -> u32 {
4298        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4299        self.excerpts.summary().widest_line_number + 1
4300    }
4301
4302    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes<'_> {
4303        let range = range.start.to_offset(self)..range.end.to_offset(self);
4304        let mut excerpts = self.cursor::<usize>();
4305        excerpts.seek(&range.start);
4306
4307        let mut chunk;
4308        let mut has_trailing_newline;
4309        let excerpt_bytes;
4310        if let Some(region) = excerpts.region() {
4311            let mut bytes = region.buffer.bytes_in_range(
4312                region.buffer_range.start + range.start - region.range.start
4313                    ..(region.buffer_range.start + range.end - region.range.start)
4314                        .min(region.buffer_range.end),
4315            );
4316            chunk = bytes.next().unwrap_or(&[][..]);
4317            excerpt_bytes = Some(bytes);
4318            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4319            if chunk.is_empty() && has_trailing_newline {
4320                chunk = b"\n";
4321                has_trailing_newline = false;
4322            }
4323        } else {
4324            chunk = &[][..];
4325            excerpt_bytes = None;
4326            has_trailing_newline = false;
4327        };
4328
4329        MultiBufferBytes {
4330            range,
4331            cursor: excerpts,
4332            excerpt_bytes,
4333            has_trailing_newline,
4334            chunk,
4335        }
4336    }
4337
4338    pub fn reversed_bytes_in_range<T: ToOffset>(
4339        &self,
4340        range: Range<T>,
4341    ) -> ReversedMultiBufferBytes<'_> {
4342        let range = range.start.to_offset(self)..range.end.to_offset(self);
4343        let mut chunks = self.reversed_chunks_in_range(range.clone());
4344        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4345        ReversedMultiBufferBytes {
4346            range,
4347            chunks,
4348            chunk,
4349        }
4350    }
4351
4352    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows<'_> {
4353        let mut cursor = self.cursor::<Point>();
4354        cursor.seek(&Point::new(start_row.0, 0));
4355        let mut result = MultiBufferRows {
4356            point: Point::new(0, 0),
4357            is_empty: self.excerpts.is_empty(),
4358            is_singleton: self.is_singleton(),
4359            cursor,
4360        };
4361        result.seek(start_row);
4362        result
4363    }
4364
4365    pub fn chunks<T: ToOffset>(
4366        &self,
4367        range: Range<T>,
4368        language_aware: bool,
4369    ) -> MultiBufferChunks<'_> {
4370        let mut chunks = MultiBufferChunks {
4371            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4372            range: 0..0,
4373            excerpts: self.excerpts.cursor(&()),
4374            diff_transforms: self.diff_transforms.cursor(&()),
4375            diffs: &self.diffs,
4376            diff_base_chunks: None,
4377            excerpt_chunks: None,
4378            buffer_chunk: None,
4379            language_aware,
4380        };
4381        let range = range.start.to_offset(self)..range.end.to_offset(self);
4382        chunks.seek(range);
4383        chunks
4384    }
4385
4386    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4387        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4388    }
4389
4390    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4391        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4392    }
4393
4394    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4395        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4396    }
4397
4398    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4399        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4400            buffer.clip_point_utf16(Unclipped(point), bias)
4401        })
4402    }
4403
4404    pub fn offset_to_point(&self, offset: usize) -> Point {
4405        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4406    }
4407
4408    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4409        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4410    }
4411
4412    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4413        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4414    }
4415
4416    pub fn point_to_offset(&self, point: Point) -> usize {
4417        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4418    }
4419
4420    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4421        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4422    }
4423
4424    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4425        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4426    }
4427
4428    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4429        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4430    }
4431
4432    fn clip_dimension<D>(
4433        &self,
4434        position: D,
4435        bias: Bias,
4436        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4437    ) -> D
4438    where
4439        D: TextDimension + Ord + Sub<D, Output = D>,
4440    {
4441        let mut cursor = self.cursor();
4442        cursor.seek(&position);
4443        if let Some(region) = cursor.region() {
4444            if position >= region.range.end {
4445                return region.range.end;
4446            }
4447            let overshoot = position - region.range.start;
4448            let mut buffer_position = region.buffer_range.start;
4449            buffer_position.add_assign(&overshoot);
4450            let clipped_buffer_position =
4451                clip_buffer_position(region.buffer, buffer_position, bias);
4452            let mut position = region.range.start;
4453            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4454            position
4455        } else {
4456            D::from_text_summary(&self.text_summary())
4457        }
4458    }
4459
4460    fn convert_dimension<D1, D2>(
4461        &self,
4462        key: D1,
4463        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4464    ) -> D2
4465    where
4466        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4467        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4468    {
4469        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4470        cursor.seek(&DimensionPair { key, value: None });
4471        if let Some(region) = cursor.region() {
4472            if key >= region.range.end.key {
4473                return region.range.end.value.unwrap();
4474            }
4475            let start_key = region.range.start.key;
4476            let start_value = region.range.start.value.unwrap();
4477            let buffer_start_key = region.buffer_range.start.key;
4478            let buffer_start_value = region.buffer_range.start.value.unwrap();
4479            let mut buffer_key = buffer_start_key;
4480            buffer_key.add_assign(&(key - start_key));
4481            let buffer_value = convert_buffer_dimension(region.buffer, buffer_key);
4482            let mut result = start_value;
4483            result.add_assign(&(buffer_value - buffer_start_value));
4484            result
4485        } else {
4486            D2::from_text_summary(&self.text_summary())
4487        }
4488    }
4489
4490    pub fn point_to_buffer_offset<T: ToOffset>(
4491        &self,
4492        point: T,
4493    ) -> Option<(&BufferSnapshot, usize)> {
4494        let offset = point.to_offset(self);
4495        let mut cursor = self.cursor::<usize>();
4496        cursor.seek(&offset);
4497        let region = cursor.region()?;
4498        let overshoot = offset - region.range.start;
4499        let buffer_offset = region.buffer_range.start + overshoot;
4500        if buffer_offset == region.buffer.len() + 1
4501            && region.has_trailing_newline
4502            && !region.is_main_buffer
4503        {
4504            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4505        } else if buffer_offset > region.buffer.len() {
4506            return None;
4507        }
4508        Some((region.buffer, buffer_offset))
4509    }
4510
4511    pub fn point_to_buffer_point(
4512        &self,
4513        point: Point,
4514    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4515        let mut cursor = self.cursor::<Point>();
4516        cursor.seek(&point);
4517        let region = cursor.region()?;
4518        let overshoot = point - region.range.start;
4519        let buffer_point = region.buffer_range.start + overshoot;
4520        let excerpt = cursor.excerpt()?;
4521        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4522            && region.has_trailing_newline
4523            && !region.is_main_buffer
4524        {
4525            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4526        } else if buffer_point > region.buffer.max_point() {
4527            return None;
4528        }
4529        Some((region.buffer, buffer_point, excerpt.id))
4530    }
4531
4532    pub fn suggested_indents(
4533        &self,
4534        rows: impl IntoIterator<Item = u32>,
4535        cx: &App,
4536    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4537        let mut result = BTreeMap::new();
4538
4539        let mut rows_for_excerpt = Vec::new();
4540        let mut cursor = self.cursor::<Point>();
4541        let mut rows = rows.into_iter().peekable();
4542        let mut prev_row = u32::MAX;
4543        let mut prev_language_indent_size = IndentSize::default();
4544
4545        while let Some(row) = rows.next() {
4546            cursor.seek(&Point::new(row, 0));
4547            let Some(region) = cursor.region() else {
4548                continue;
4549            };
4550
4551            // Retrieve the language and indent size once for each disjoint region being indented.
4552            let single_indent_size = if row.saturating_sub(1) == prev_row {
4553                prev_language_indent_size
4554            } else {
4555                region
4556                    .buffer
4557                    .language_indent_size_at(Point::new(row, 0), cx)
4558            };
4559            prev_language_indent_size = single_indent_size;
4560            prev_row = row;
4561
4562            let start_buffer_row = region.buffer_range.start.row;
4563            let start_multibuffer_row = region.range.start.row;
4564            let end_multibuffer_row = region.range.end.row;
4565
4566            rows_for_excerpt.push(row);
4567            while let Some(next_row) = rows.peek().copied() {
4568                if end_multibuffer_row > next_row {
4569                    rows_for_excerpt.push(next_row);
4570                    rows.next();
4571                } else {
4572                    break;
4573                }
4574            }
4575
4576            let buffer_rows = rows_for_excerpt
4577                .drain(..)
4578                .map(|row| start_buffer_row + row - start_multibuffer_row);
4579            let buffer_indents = region
4580                .buffer
4581                .suggested_indents(buffer_rows, single_indent_size);
4582            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4583                (
4584                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4585                    indent,
4586                )
4587            });
4588            result.extend(multibuffer_indents);
4589        }
4590
4591        result
4592    }
4593
4594    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4595        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4596            let mut size = buffer.indent_size_for_line(range.start.row);
4597            size.len = size
4598                .len
4599                .min(range.end.column)
4600                .saturating_sub(range.start.column);
4601            size
4602        } else {
4603            IndentSize::spaces(0)
4604        }
4605    }
4606
4607    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4608        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4609            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4610        } else {
4611            LineIndent::spaces(0)
4612        }
4613    }
4614
4615    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4616        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4617
4618        if self.language_settings(cx).extend_comment_on_newline
4619            && let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0))
4620        {
4621            let delimiters = language_scope.line_comment_prefixes();
4622            for delimiter in delimiters {
4623                if *self
4624                    .chars_at(Point::new(row.0, indent.len() as u32))
4625                    .take(delimiter.chars().count())
4626                    .collect::<String>()
4627                    .as_str()
4628                    == **delimiter
4629                {
4630                    indent.push_str(delimiter);
4631                    break;
4632                }
4633            }
4634        }
4635
4636        indent
4637    }
4638
4639    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4640    where
4641        T: ToOffset,
4642    {
4643        for char in self.reversed_chars_at(position) {
4644            if !char.is_whitespace() {
4645                return false;
4646            }
4647            if char == '\n' {
4648                return true;
4649            }
4650        }
4651        true
4652    }
4653
4654    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4655        while row.0 > 0 {
4656            row.0 -= 1;
4657            if !self.is_line_blank(row) {
4658                return Some(row);
4659            }
4660        }
4661        None
4662    }
4663
4664    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4665        if let Some((_, range)) = self.buffer_line_for_row(row) {
4666            range.end.column - range.start.column
4667        } else {
4668            0
4669        }
4670    }
4671
4672    pub fn buffer_line_for_row(
4673        &self,
4674        row: MultiBufferRow,
4675    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4676        let mut cursor = self.cursor::<Point>();
4677        let point = Point::new(row.0, 0);
4678        cursor.seek(&point);
4679        let region = cursor.region()?;
4680        let overshoot = point.min(region.range.end) - region.range.start;
4681        let buffer_point = region.buffer_range.start + overshoot;
4682        if buffer_point.row > region.buffer_range.end.row {
4683            return None;
4684        }
4685        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4686        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4687            .min(region.buffer_range.end);
4688        Some((region.buffer, line_start..line_end))
4689    }
4690
4691    pub fn max_point(&self) -> Point {
4692        self.text_summary().lines
4693    }
4694
4695    pub fn max_row(&self) -> MultiBufferRow {
4696        MultiBufferRow(self.text_summary().lines.row)
4697    }
4698
4699    pub fn text_summary(&self) -> TextSummary {
4700        self.diff_transforms.summary().output
4701    }
4702
4703    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4704    where
4705        D: TextDimension,
4706        O: ToOffset,
4707    {
4708        let range = range.start.to_offset(self)..range.end.to_offset(self);
4709        let mut cursor = self
4710            .diff_transforms
4711            .cursor::<Dimensions<usize, ExcerptOffset>>(&());
4712        cursor.seek(&range.start, Bias::Right);
4713
4714        let Some(first_transform) = cursor.item() else {
4715            return D::from_text_summary(&TextSummary::default());
4716        };
4717
4718        let diff_transform_start = cursor.start().0;
4719        let diff_transform_end = cursor.end().0;
4720        let diff_start = range.start;
4721        let start_overshoot = diff_start - diff_transform_start;
4722        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4723
4724        let mut result = match first_transform {
4725            DiffTransform::BufferContent { .. } => {
4726                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4727                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4728                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4729            }
4730            DiffTransform::DeletedHunk {
4731                buffer_id,
4732                base_text_byte_range,
4733                has_trailing_newline,
4734                ..
4735            } => {
4736                let buffer_start = base_text_byte_range.start + start_overshoot;
4737                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4738                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4739                    panic!("{:?} is in non-existent deleted hunk", range.start)
4740                };
4741
4742                let include_trailing_newline =
4743                    *has_trailing_newline && range.end >= diff_transform_end;
4744                if include_trailing_newline {
4745                    buffer_end -= 1;
4746                }
4747
4748                let mut summary =
4749                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4750
4751                if include_trailing_newline {
4752                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4753                }
4754
4755                summary
4756            }
4757        };
4758        if range.end < diff_transform_end {
4759            return result;
4760        }
4761
4762        cursor.next();
4763        result.add_assign(&D::from_text_summary(
4764            &cursor.summary(&range.end, Bias::Right),
4765        ));
4766
4767        let Some(last_transform) = cursor.item() else {
4768            return result;
4769        };
4770
4771        let overshoot = range.end - cursor.start().0;
4772        let suffix = match last_transform {
4773            DiffTransform::BufferContent { .. } => {
4774                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4775                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4776            }
4777            DiffTransform::DeletedHunk {
4778                base_text_byte_range,
4779                buffer_id,
4780                has_trailing_newline,
4781                ..
4782            } => {
4783                let buffer_end = base_text_byte_range.start + overshoot;
4784                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4785                    panic!("{:?} is in non-existent deleted hunk", range.end)
4786                };
4787
4788                let mut suffix = base_text
4789                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4790                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4791                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4792                }
4793                suffix
4794            }
4795        };
4796
4797        result.add_assign(&suffix);
4798        result
4799    }
4800
4801    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4802    where
4803        D: TextDimension,
4804    {
4805        // let mut range = range.start..range.end;
4806        let mut summary = D::zero(&());
4807        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4808        cursor.seek(&range.start, Bias::Right);
4809        if let Some(excerpt) = cursor.item() {
4810            let mut end_before_newline = cursor.end();
4811            if excerpt.has_trailing_newline {
4812                end_before_newline -= ExcerptOffset::new(1);
4813            }
4814
4815            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4816            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4817            let end_in_excerpt =
4818                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4819            summary.add_assign(
4820                &excerpt
4821                    .buffer
4822                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4823            );
4824
4825            if range.end > end_before_newline {
4826                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4827            }
4828
4829            cursor.next();
4830        }
4831
4832        if range.end > *cursor.start() {
4833            summary.add_assign(
4834                &cursor
4835                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right)
4836                    .0,
4837            );
4838            if let Some(excerpt) = cursor.item() {
4839                range.end = cmp::max(*cursor.start(), range.end);
4840
4841                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4842                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4843                summary.add_assign(
4844                    &excerpt
4845                        .buffer
4846                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4847                );
4848            }
4849        }
4850
4851        summary
4852    }
4853
4854    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4855    where
4856        D: TextDimension + Ord + Sub<D, Output = D>,
4857    {
4858        self.summaries_for_anchors([anchor])[0]
4859    }
4860
4861    fn resolve_summary_for_anchor<D>(
4862        &self,
4863        anchor: &Anchor,
4864        excerpt_position: D,
4865        diff_transforms: &mut Cursor<
4866            DiffTransform,
4867            Dimensions<ExcerptDimension<D>, OutputDimension<D>>,
4868        >,
4869    ) -> D
4870    where
4871        D: TextDimension + Ord + Sub<D, Output = D>,
4872    {
4873        loop {
4874            let transform_end_position = diff_transforms.end().0.0;
4875            let at_transform_end =
4876                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4877            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4878                diff_transforms.next();
4879                continue;
4880            }
4881
4882            let mut position = diff_transforms.start().1.0;
4883            match diff_transforms.item() {
4884                Some(DiffTransform::DeletedHunk {
4885                    buffer_id,
4886                    base_text_byte_range,
4887                    ..
4888                }) => {
4889                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor
4890                        && let Some(base_text) =
4891                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4892                        && base_text.can_resolve(diff_base_anchor)
4893                    {
4894                        let base_text_offset = diff_base_anchor.to_offset(base_text);
4895                        if base_text_offset >= base_text_byte_range.start
4896                            && base_text_offset <= base_text_byte_range.end
4897                        {
4898                            let position_in_hunk = base_text.text_summary_for_range::<D, _>(
4899                                base_text_byte_range.start..base_text_offset,
4900                            );
4901                            position.add_assign(&position_in_hunk);
4902                        } else if at_transform_end {
4903                            diff_transforms.next();
4904                            continue;
4905                        }
4906                    }
4907                }
4908                _ => {
4909                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4910                        diff_transforms.next();
4911                        continue;
4912                    }
4913                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4914                    position.add_assign(&overshoot);
4915                }
4916            }
4917
4918            return position;
4919        }
4920    }
4921
4922    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4923        let mut cursor = self
4924            .excerpts
4925            .cursor::<Dimensions<Option<&Locator>, ExcerptOffset>>(&());
4926        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4927
4928        cursor.seek(&Some(locator), Bias::Left);
4929        if cursor.item().is_none() {
4930            cursor.next();
4931        }
4932
4933        let mut position = cursor.start().1;
4934        if let Some(excerpt) = cursor.item()
4935            && excerpt.id == anchor.excerpt_id
4936        {
4937            let excerpt_buffer_start = excerpt
4938                .buffer
4939                .offset_for_anchor(&excerpt.range.context.start);
4940            let excerpt_buffer_end = excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4941            let buffer_position = cmp::min(
4942                excerpt_buffer_end,
4943                excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4944            );
4945            if buffer_position > excerpt_buffer_start {
4946                position.value += buffer_position - excerpt_buffer_start;
4947            }
4948        }
4949        position
4950    }
4951
4952    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4953        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4954            excerpt_id = *replacement;
4955        }
4956        excerpt_id
4957    }
4958
4959    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4960    where
4961        D: TextDimension + Ord + Sub<D, Output = D>,
4962        I: 'a + IntoIterator<Item = &'a Anchor>,
4963    {
4964        let mut anchors = anchors.into_iter().peekable();
4965        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4966        let mut diff_transforms_cursor = self
4967            .diff_transforms
4968            .cursor::<Dimensions<ExcerptDimension<D>, OutputDimension<D>>>(&());
4969        diff_transforms_cursor.next();
4970
4971        let mut summaries = Vec::new();
4972        while let Some(anchor) = anchors.peek() {
4973            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4974            let excerpt_anchors = iter::from_fn(|| {
4975                let anchor = anchors.peek()?;
4976                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4977                    Some(anchors.next().unwrap())
4978                } else {
4979                    None
4980                }
4981            });
4982
4983            let locator = self.excerpt_locator_for_id(excerpt_id);
4984            cursor.seek_forward(locator, Bias::Left);
4985            if cursor.item().is_none() {
4986                cursor.next();
4987            }
4988
4989            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4990            if let Some(excerpt) = cursor.item() {
4991                if excerpt.id != excerpt_id {
4992                    let position = self.resolve_summary_for_anchor(
4993                        &Anchor::min(),
4994                        excerpt_start_position,
4995                        &mut diff_transforms_cursor,
4996                    );
4997                    summaries.extend(excerpt_anchors.map(|_| position));
4998                    continue;
4999                }
5000                let excerpt_buffer_start =
5001                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
5002                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
5003                for (buffer_summary, anchor) in excerpt
5004                    .buffer
5005                    .summaries_for_anchors_with_payload::<D, _, _>(
5006                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
5007                    )
5008                {
5009                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
5010                    let mut position = excerpt_start_position;
5011                    if summary > excerpt_buffer_start {
5012                        position.add_assign(&(summary - excerpt_buffer_start));
5013                    }
5014
5015                    if position > diff_transforms_cursor.start().0.0 {
5016                        diff_transforms_cursor
5017                            .seek_forward(&ExcerptDimension(position), Bias::Left);
5018                    }
5019
5020                    summaries.push(self.resolve_summary_for_anchor(
5021                        anchor,
5022                        position,
5023                        &mut diff_transforms_cursor,
5024                    ));
5025                }
5026            } else {
5027                diff_transforms_cursor
5028                    .seek_forward(&ExcerptDimension(excerpt_start_position), Bias::Left);
5029                let position = self.resolve_summary_for_anchor(
5030                    &Anchor::max(),
5031                    excerpt_start_position,
5032                    &mut diff_transforms_cursor,
5033                );
5034                summaries.extend(excerpt_anchors.map(|_| position));
5035            }
5036        }
5037
5038        summaries
5039    }
5040
5041    pub fn dimensions_from_points<'a, D>(
5042        &'a self,
5043        points: impl 'a + IntoIterator<Item = Point>,
5044    ) -> impl 'a + Iterator<Item = D>
5045    where
5046        D: TextDimension + Sub<D, Output = D>,
5047    {
5048        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
5049        cursor.seek(&DimensionPair {
5050            key: Point::default(),
5051            value: None,
5052        });
5053        let mut points = points.into_iter();
5054        iter::from_fn(move || {
5055            let point = points.next()?;
5056
5057            cursor.seek_forward(&DimensionPair {
5058                key: point,
5059                value: None,
5060            });
5061
5062            if let Some(region) = cursor.region() {
5063                let overshoot = point - region.range.start.key;
5064                let buffer_point = region.buffer_range.start.key + overshoot;
5065                let mut position = region.range.start.value.unwrap();
5066                position.add_assign(
5067                    &region
5068                        .buffer
5069                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
5070                );
5071                if point == region.range.end.key && region.has_trailing_newline {
5072                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
5073                }
5074                Some(position)
5075            } else {
5076                Some(D::from_text_summary(&self.text_summary()))
5077            }
5078        })
5079    }
5080
5081    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
5082    where
5083        I: 'a + IntoIterator<Item = &'a Anchor>,
5084    {
5085        let mut anchors = anchors.into_iter().enumerate().peekable();
5086        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5087        cursor.next();
5088
5089        let mut result = Vec::new();
5090
5091        while let Some((_, anchor)) = anchors.peek() {
5092            let old_excerpt_id = anchor.excerpt_id;
5093
5094            // Find the location where this anchor's excerpt should be.
5095            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5096            cursor.seek_forward(&Some(old_locator), Bias::Left);
5097
5098            if cursor.item().is_none() {
5099                cursor.next();
5100            }
5101
5102            let next_excerpt = cursor.item();
5103            let prev_excerpt = cursor.prev_item();
5104
5105            // Process all of the anchors for this excerpt.
5106            while let Some((_, anchor)) = anchors.peek() {
5107                if anchor.excerpt_id != old_excerpt_id {
5108                    break;
5109                }
5110                let (anchor_ix, anchor) = anchors.next().unwrap();
5111                let mut anchor = *anchor;
5112
5113                // Leave min and max anchors unchanged if invalid or
5114                // if the old excerpt still exists at this location
5115                let mut kept_position = next_excerpt
5116                    .is_some_and(|e| e.id == old_excerpt_id && e.contains(&anchor))
5117                    || old_excerpt_id == ExcerptId::max()
5118                    || old_excerpt_id == ExcerptId::min();
5119
5120                // If the old excerpt no longer exists at this location, then attempt to
5121                // find an equivalent position for this anchor in an adjacent excerpt.
5122                if !kept_position {
5123                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5124                        if excerpt.contains(&anchor) {
5125                            anchor.excerpt_id = excerpt.id;
5126                            kept_position = true;
5127                            break;
5128                        }
5129                    }
5130                }
5131
5132                // If there's no adjacent excerpt that contains the anchor's position,
5133                // then report that the anchor has lost its position.
5134                if !kept_position {
5135                    anchor = if let Some(excerpt) = next_excerpt {
5136                        let mut text_anchor = excerpt
5137                            .range
5138                            .context
5139                            .start
5140                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5141                        if text_anchor
5142                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5143                            .is_gt()
5144                        {
5145                            text_anchor = excerpt.range.context.end;
5146                        }
5147                        Anchor {
5148                            buffer_id: Some(excerpt.buffer_id),
5149                            excerpt_id: excerpt.id,
5150                            text_anchor,
5151                            diff_base_anchor: None,
5152                        }
5153                    } else if let Some(excerpt) = prev_excerpt {
5154                        let mut text_anchor = excerpt
5155                            .range
5156                            .context
5157                            .end
5158                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5159                        if text_anchor
5160                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5161                            .is_lt()
5162                        {
5163                            text_anchor = excerpt.range.context.start;
5164                        }
5165                        Anchor {
5166                            buffer_id: Some(excerpt.buffer_id),
5167                            excerpt_id: excerpt.id,
5168                            text_anchor,
5169                            diff_base_anchor: None,
5170                        }
5171                    } else if anchor.text_anchor.bias == Bias::Left {
5172                        Anchor::min()
5173                    } else {
5174                        Anchor::max()
5175                    };
5176                }
5177
5178                result.push((anchor_ix, anchor, kept_position));
5179            }
5180        }
5181        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5182        result
5183    }
5184
5185    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5186        self.anchor_at(position, Bias::Left)
5187    }
5188
5189    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5190        self.anchor_at(position, Bias::Right)
5191    }
5192
5193    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5194        let offset = position.to_offset(self);
5195
5196        // Find the given position in the diff transforms. Determine the corresponding
5197        // offset in the excerpts, and whether the position is within a deleted hunk.
5198        let mut diff_transforms = self
5199            .diff_transforms
5200            .cursor::<Dimensions<usize, ExcerptOffset>>(&());
5201        diff_transforms.seek(&offset, Bias::Right);
5202
5203        if offset == diff_transforms.start().0
5204            && bias == Bias::Left
5205            && let Some(prev_item) = diff_transforms.prev_item()
5206            && let DiffTransform::DeletedHunk { .. } = prev_item
5207        {
5208            diff_transforms.prev();
5209        }
5210        let offset_in_transform = offset - diff_transforms.start().0;
5211        let mut excerpt_offset = diff_transforms.start().1;
5212        let mut diff_base_anchor = None;
5213        if let Some(DiffTransform::DeletedHunk {
5214            buffer_id,
5215            base_text_byte_range,
5216            has_trailing_newline,
5217            ..
5218        }) = diff_transforms.item()
5219        {
5220            let diff = self.diffs.get(buffer_id).expect("missing diff");
5221            if offset_in_transform > base_text_byte_range.len() {
5222                debug_assert!(*has_trailing_newline);
5223                bias = Bias::Right;
5224            } else {
5225                diff_base_anchor = Some(
5226                    diff.base_text()
5227                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5228                );
5229                bias = Bias::Left;
5230            }
5231        } else {
5232            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5233        };
5234
5235        let mut excerpts = self
5236            .excerpts
5237            .cursor::<Dimensions<ExcerptOffset, Option<ExcerptId>>>(&());
5238        excerpts.seek(&excerpt_offset, Bias::Right);
5239        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5240            excerpts.prev();
5241        }
5242        if let Some(excerpt) = excerpts.item() {
5243            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5244            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end().0 {
5245                overshoot -= 1;
5246                bias = Bias::Right;
5247            }
5248
5249            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5250            let text_anchor =
5251                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5252            Anchor {
5253                buffer_id: Some(excerpt.buffer_id),
5254                excerpt_id: excerpt.id,
5255                text_anchor,
5256                diff_base_anchor,
5257            }
5258        } else {
5259            let mut anchor = if excerpt_offset.is_zero() && bias == Bias::Left {
5260                Anchor::min()
5261            } else {
5262                Anchor::max()
5263            };
5264            // TODO this is a hack, remove it
5265            if let Some((excerpt_id, _, _)) = self.as_singleton() {
5266                anchor.excerpt_id = *excerpt_id;
5267            }
5268            anchor
5269        }
5270    }
5271
5272    /// Returns an anchor for the given excerpt and text anchor,
5273    /// returns None if the excerpt_id is no longer valid.
5274    pub fn anchor_in_excerpt(
5275        &self,
5276        excerpt_id: ExcerptId,
5277        text_anchor: text::Anchor,
5278    ) -> Option<Anchor> {
5279        let excerpt_id = self.latest_excerpt_id(excerpt_id);
5280        let locator = self.excerpt_locator_for_id(excerpt_id);
5281        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5282        cursor.seek(locator, Bias::Left);
5283        if let Some(excerpt) = cursor.item()
5284            && excerpt.id == excerpt_id
5285        {
5286            let text_anchor = excerpt.clip_anchor(text_anchor);
5287            drop(cursor);
5288            return Some(Anchor {
5289                buffer_id: Some(excerpt.buffer_id),
5290                excerpt_id,
5291                text_anchor,
5292                diff_base_anchor: None,
5293            });
5294        }
5295        None
5296    }
5297
5298    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5299        Some(self.excerpt(excerpt_id)?.range.context.clone())
5300    }
5301
5302    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5303        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5304            true
5305        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5306            excerpt.buffer.can_resolve(&anchor.text_anchor)
5307        } else {
5308            false
5309        }
5310    }
5311
5312    pub fn excerpts(
5313        &self,
5314    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5315        self.excerpts
5316            .iter()
5317            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5318    }
5319
5320    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<'_, D> {
5321        let excerpts = self.excerpts.cursor(&());
5322        let diff_transforms = self.diff_transforms.cursor(&());
5323        MultiBufferCursor {
5324            excerpts,
5325            diff_transforms,
5326            diffs: &self.diffs,
5327            cached_region: None,
5328        }
5329    }
5330
5331    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5332        let start_locator = self.excerpt_locator_for_id(id);
5333        let mut excerpts = self
5334            .excerpts
5335            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<usize>>>(&());
5336        excerpts.seek(&Some(start_locator), Bias::Left);
5337        excerpts.prev();
5338
5339        let mut diff_transforms = self.diff_transforms.cursor::<DiffTransforms<usize>>(&());
5340        diff_transforms.seek(&excerpts.start().1, Bias::Left);
5341        if diff_transforms.end().excerpt_dimension < excerpts.start().1 {
5342            diff_transforms.next();
5343        }
5344
5345        let excerpt = excerpts.item()?;
5346        Some(MultiBufferExcerpt {
5347            excerpt,
5348            offset: diff_transforms.start().output_dimension.0,
5349            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5350            excerpt_offset: excerpts.start().1.clone(),
5351            diff_transforms,
5352        })
5353    }
5354
5355    pub fn excerpt_boundaries_in_range<R, T>(
5356        &self,
5357        range: R,
5358    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5359    where
5360        R: RangeBounds<T>,
5361        T: ToOffset,
5362    {
5363        let start_offset;
5364        let start = match range.start_bound() {
5365            Bound::Included(start) => {
5366                start_offset = start.to_offset(self);
5367                Bound::Included(start_offset)
5368            }
5369            Bound::Excluded(_) => {
5370                panic!("not supported")
5371            }
5372            Bound::Unbounded => {
5373                start_offset = 0;
5374                Bound::Unbounded
5375            }
5376        };
5377        let end = match range.end_bound() {
5378            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5379            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5380            Bound::Unbounded => Bound::Unbounded,
5381        };
5382        let bounds = (start, end);
5383
5384        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5385        cursor.seek(&DimensionPair {
5386            key: start_offset,
5387            value: None,
5388        });
5389
5390        if cursor
5391            .region()
5392            .is_some_and(|region| bounds.contains(&region.range.start.key))
5393        {
5394            cursor.prev_excerpt();
5395        } else {
5396            cursor.seek_to_start_of_current_excerpt();
5397        }
5398        let mut prev_region = cursor.region();
5399
5400        cursor.next_excerpt();
5401
5402        iter::from_fn(move || {
5403            loop {
5404                if self.singleton {
5405                    return None;
5406                }
5407
5408                let next_region = cursor.region()?;
5409                cursor.next_excerpt();
5410                if !bounds.contains(&next_region.range.start.key) {
5411                    prev_region = Some(next_region);
5412                    continue;
5413                }
5414
5415                let next_region_start = next_region.range.start.value.unwrap();
5416                let next_region_end = if let Some(region) = cursor.region() {
5417                    region.range.start.value.unwrap()
5418                } else {
5419                    self.max_point()
5420                };
5421
5422                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5423                    id: region.excerpt.id,
5424                    buffer: region.excerpt.buffer.clone(),
5425                    buffer_id: region.excerpt.buffer_id,
5426                    range: region.excerpt.range.clone(),
5427                    end_row: MultiBufferRow(next_region_start.row),
5428                });
5429
5430                let next = ExcerptInfo {
5431                    id: next_region.excerpt.id,
5432                    buffer: next_region.excerpt.buffer.clone(),
5433                    buffer_id: next_region.excerpt.buffer_id,
5434                    range: next_region.excerpt.range.clone(),
5435                    end_row: if next_region.excerpt.has_trailing_newline {
5436                        MultiBufferRow(next_region_end.row - 1)
5437                    } else {
5438                        MultiBufferRow(next_region_end.row)
5439                    },
5440                };
5441
5442                let row = MultiBufferRow(next_region_start.row);
5443
5444                prev_region = Some(next_region);
5445
5446                return Some(ExcerptBoundary { row, prev, next });
5447            }
5448        })
5449    }
5450
5451    pub fn edit_count(&self) -> usize {
5452        self.edit_count
5453    }
5454
5455    pub fn non_text_state_update_count(&self) -> usize {
5456        self.non_text_state_update_count
5457    }
5458
5459    /// Returns the smallest enclosing bracket ranges containing the given range or
5460    /// None if no brackets contain range or the range is not contained in a single
5461    /// excerpt
5462    ///
5463    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5464    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5465        &self,
5466        range: Range<T>,
5467        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5468    ) -> Option<(Range<usize>, Range<usize>)> {
5469        let range = range.start.to_offset(self)..range.end.to_offset(self);
5470        let mut excerpt = self.excerpt_containing(range.clone())?;
5471        let buffer = excerpt.buffer();
5472        let excerpt_buffer_range = excerpt.buffer_range();
5473
5474        // Filter to ranges contained in the excerpt
5475        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5476            excerpt_buffer_range.contains(&open.start)
5477                && excerpt_buffer_range.contains(&close.end)
5478                && range_filter.is_none_or(|filter| filter(buffer, open, close))
5479        };
5480
5481        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5482            excerpt.map_range_to_buffer(range),
5483            Some(&range_filter),
5484        )?;
5485
5486        Some((
5487            excerpt.map_range_from_buffer(open),
5488            excerpt.map_range_from_buffer(close),
5489        ))
5490    }
5491
5492    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5493    /// not contained in a single excerpt
5494    pub fn enclosing_bracket_ranges<T: ToOffset>(
5495        &self,
5496        range: Range<T>,
5497    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5498        let range = range.start.to_offset(self)..range.end.to_offset(self);
5499        let mut excerpt = self.excerpt_containing(range.clone())?;
5500
5501        Some(
5502            excerpt
5503                .buffer()
5504                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5505                .filter_map(move |pair| {
5506                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5507                        Some((
5508                            excerpt.map_range_from_buffer(pair.open_range),
5509                            excerpt.map_range_from_buffer(pair.close_range),
5510                        ))
5511                    } else {
5512                        None
5513                    }
5514                }),
5515        )
5516    }
5517
5518    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5519    /// not contained in a single excerpt
5520    pub fn text_object_ranges<T: ToOffset>(
5521        &self,
5522        range: Range<T>,
5523        options: TreeSitterOptions,
5524    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5525        let range = range.start.to_offset(self)..range.end.to_offset(self);
5526        self.excerpt_containing(range.clone())
5527            .map(|mut excerpt| {
5528                excerpt
5529                    .buffer()
5530                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5531                    .filter_map(move |(range, text_object)| {
5532                        if excerpt.contains_buffer_range(range.clone()) {
5533                            Some((excerpt.map_range_from_buffer(range), text_object))
5534                        } else {
5535                            None
5536                        }
5537                    })
5538            })
5539            .into_iter()
5540            .flatten()
5541    }
5542
5543    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5544    /// not contained in a single excerpt
5545    pub fn bracket_ranges<T: ToOffset>(
5546        &self,
5547        range: Range<T>,
5548    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5549        let range = range.start.to_offset(self)..range.end.to_offset(self);
5550        let mut excerpt = self.excerpt_containing(range.clone())?;
5551
5552        Some(
5553            excerpt
5554                .buffer()
5555                .bracket_ranges(excerpt.map_range_to_buffer(range))
5556                .filter_map(move |pair| {
5557                    let buffer_range = pair.open_range.start..pair.close_range.end;
5558                    if excerpt.contains_buffer_range(buffer_range) {
5559                        Some((
5560                            excerpt.map_range_from_buffer(pair.open_range),
5561                            excerpt.map_range_from_buffer(pair.close_range),
5562                        ))
5563                    } else {
5564                        None
5565                    }
5566                }),
5567        )
5568    }
5569
5570    pub fn redacted_ranges<'a, T: ToOffset>(
5571        &'a self,
5572        range: Range<T>,
5573        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5574    ) -> impl Iterator<Item = Range<usize>> + 'a {
5575        let range = range.start.to_offset(self)..range.end.to_offset(self);
5576        self.lift_buffer_metadata(range, move |buffer, range| {
5577            if redaction_enabled(buffer.file()) {
5578                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5579            } else {
5580                None
5581            }
5582        })
5583        .map(|(range, _, _)| range)
5584    }
5585
5586    pub fn runnable_ranges(
5587        &self,
5588        range: Range<Anchor>,
5589    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5590        let range = range.start.to_offset(self)..range.end.to_offset(self);
5591        self.lift_buffer_metadata(range, move |buffer, range| {
5592            Some(
5593                buffer
5594                    .runnable_ranges(range.clone())
5595                    .filter(move |runnable| {
5596                        runnable.run_range.start >= range.start
5597                            && runnable.run_range.end < range.end
5598                    })
5599                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5600            )
5601        })
5602        .map(|(run_range, runnable, _)| language::RunnableRange {
5603            run_range,
5604            ..runnable
5605        })
5606    }
5607
5608    pub fn line_indents(
5609        &self,
5610        start_row: MultiBufferRow,
5611        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5612    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5613        let max_point = self.max_point();
5614        let mut cursor = self.cursor::<Point>();
5615        cursor.seek(&Point::new(start_row.0, 0));
5616        iter::from_fn(move || {
5617            let mut region = cursor.region()?;
5618            while !buffer_filter(&region.excerpt.buffer) {
5619                cursor.next();
5620                region = cursor.region()?;
5621            }
5622            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5623            let buffer_start_row =
5624                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5625
5626            let buffer_end_row = if region.is_main_buffer
5627                && (region.has_trailing_newline || region.range.end == max_point)
5628            {
5629                region.buffer_range.end.row
5630            } else {
5631                region.buffer_range.end.row.saturating_sub(1)
5632            };
5633
5634            let line_indents = region
5635                .buffer
5636                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5637            cursor.next();
5638            Some(line_indents.map(move |(buffer_row, indent)| {
5639                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5640                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5641            }))
5642        })
5643        .flatten()
5644    }
5645
5646    pub fn reversed_line_indents(
5647        &self,
5648        end_row: MultiBufferRow,
5649        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5650    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5651        let max_point = self.max_point();
5652        let mut cursor = self.cursor::<Point>();
5653        cursor.seek(&Point::new(end_row.0, 0));
5654        iter::from_fn(move || {
5655            let mut region = cursor.region()?;
5656            while !buffer_filter(&region.excerpt.buffer) {
5657                cursor.prev();
5658                region = cursor.region()?;
5659            }
5660
5661            let buffer_start_row = region.buffer_range.start.row;
5662            let buffer_end_row = if region.is_main_buffer
5663                && (region.has_trailing_newline || region.range.end == max_point)
5664            {
5665                region.buffer_range.end.row + 1
5666            } else {
5667                region.buffer_range.end.row
5668            };
5669
5670            let overshoot = end_row.0 - region.range.start.row;
5671            let buffer_end_row =
5672                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5673
5674            let line_indents = region
5675                .buffer
5676                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5677            cursor.prev();
5678            Some(line_indents.map(move |(buffer_row, indent)| {
5679                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5680                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5681            }))
5682        })
5683        .flatten()
5684    }
5685
5686    pub async fn enclosing_indent(
5687        &self,
5688        mut target_row: MultiBufferRow,
5689    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5690        let max_row = MultiBufferRow(self.max_point().row);
5691        if target_row >= max_row {
5692            return None;
5693        }
5694
5695        let mut target_indent = self.line_indent_for_row(target_row);
5696
5697        // If the current row is at the start of an indented block, we want to return this
5698        // block as the enclosing indent.
5699        if !target_indent.is_line_empty() && target_row < max_row {
5700            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5701            if !next_line_indent.is_line_empty()
5702                && target_indent.raw_len() < next_line_indent.raw_len()
5703            {
5704                target_indent = next_line_indent;
5705                target_row.0 += 1;
5706            }
5707        }
5708
5709        const SEARCH_ROW_LIMIT: u32 = 25000;
5710        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5711        const YIELD_INTERVAL: u32 = 100;
5712
5713        let mut accessed_row_counter = 0;
5714
5715        // If there is a blank line at the current row, search for the next non indented lines
5716        if target_indent.is_line_empty() {
5717            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5718            let end =
5719                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5720
5721            let mut non_empty_line_above = None;
5722            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5723                if row < start {
5724                    break;
5725                }
5726                accessed_row_counter += 1;
5727                if accessed_row_counter == YIELD_INTERVAL {
5728                    accessed_row_counter = 0;
5729                    yield_now().await;
5730                }
5731                if !indent.is_line_empty() {
5732                    non_empty_line_above = Some((row, indent));
5733                    break;
5734                }
5735            }
5736
5737            let mut non_empty_line_below = None;
5738            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5739                if row > end {
5740                    break;
5741                }
5742                accessed_row_counter += 1;
5743                if accessed_row_counter == YIELD_INTERVAL {
5744                    accessed_row_counter = 0;
5745                    yield_now().await;
5746                }
5747                if !indent.is_line_empty() {
5748                    non_empty_line_below = Some((row, indent));
5749                    break;
5750                }
5751            }
5752
5753            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5754                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5755                    if above_indent.raw_len() >= below_indent.raw_len() {
5756                        (above_row, above_indent)
5757                    } else {
5758                        (below_row, below_indent)
5759                    }
5760                }
5761                (Some(above), None) => above,
5762                (None, Some(below)) => below,
5763                _ => return None,
5764            };
5765
5766            target_indent = indent;
5767            target_row = row;
5768        }
5769
5770        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5771        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5772
5773        let mut start_indent = None;
5774        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5775            if row < start {
5776                break;
5777            }
5778            accessed_row_counter += 1;
5779            if accessed_row_counter == YIELD_INTERVAL {
5780                accessed_row_counter = 0;
5781                yield_now().await;
5782            }
5783            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5784                start_indent = Some((row, indent));
5785                break;
5786            }
5787        }
5788        let (start_row, start_indent_size) = start_indent?;
5789
5790        let mut end_indent = (end, None);
5791        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5792            if row > end {
5793                break;
5794            }
5795            accessed_row_counter += 1;
5796            if accessed_row_counter == YIELD_INTERVAL {
5797                accessed_row_counter = 0;
5798                yield_now().await;
5799            }
5800            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5801                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5802                break;
5803            }
5804        }
5805        let (end_row, end_indent_size) = end_indent;
5806
5807        let indent = if let Some(end_indent_size) = end_indent_size {
5808            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5809                start_indent_size
5810            } else {
5811                end_indent_size
5812            }
5813        } else {
5814            start_indent_size
5815        };
5816
5817        Some((start_row..end_row, indent))
5818    }
5819
5820    pub fn indent_guides_in_range<T: ToPoint>(
5821        &self,
5822        range: Range<T>,
5823        ignore_disabled_for_language: bool,
5824        cx: &App,
5825    ) -> impl Iterator<Item = IndentGuide> {
5826        let range = range.start.to_point(self)..range.end.to_point(self);
5827        let start_row = MultiBufferRow(range.start.row);
5828        let end_row = MultiBufferRow(range.end.row);
5829
5830        let mut row_indents = self.line_indents(start_row, |buffer| {
5831            let settings =
5832                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5833            settings.indent_guides.enabled || ignore_disabled_for_language
5834        });
5835
5836        let mut result = Vec::new();
5837        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5838
5839        let mut prev_settings = None;
5840        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5841            if first_row > end_row {
5842                break;
5843            }
5844            let current_depth = indent_stack.len() as u32;
5845
5846            // Avoid retrieving the language settings repeatedly for every buffer row.
5847            if let Some((prev_buffer_id, _)) = &prev_settings
5848                && prev_buffer_id != &buffer.remote_id()
5849            {
5850                prev_settings.take();
5851            }
5852            let settings = &prev_settings
5853                .get_or_insert_with(|| {
5854                    (
5855                        buffer.remote_id(),
5856                        language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx),
5857                    )
5858                })
5859                .1;
5860            let tab_size = settings.tab_size.get();
5861
5862            // When encountering empty, continue until found useful line indent
5863            // then add to the indent stack with the depth found
5864            let mut found_indent = false;
5865            let mut last_row = first_row;
5866            if line_indent.is_line_blank() {
5867                while !found_indent {
5868                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5869                        break;
5870                    };
5871                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5872                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5873                        break;
5874                    }
5875
5876                    if new_line_indent.is_line_blank() {
5877                        continue;
5878                    }
5879                    last_row = target_row.min(end_row);
5880                    line_indent = new_line_indent;
5881                    found_indent = true;
5882                    break;
5883                }
5884            } else {
5885                found_indent = true
5886            }
5887
5888            let depth = if found_indent {
5889                line_indent.len(tab_size) / tab_size
5890            } else {
5891                0
5892            };
5893
5894            match depth.cmp(&current_depth) {
5895                cmp::Ordering::Less => {
5896                    for _ in 0..(current_depth - depth) {
5897                        let mut indent = indent_stack.pop().unwrap();
5898                        if last_row != first_row {
5899                            // In this case, we landed on an empty row, had to seek forward,
5900                            // and discovered that the indent we where on is ending.
5901                            // This means that the last display row must
5902                            // be on line that ends this indent range, so we
5903                            // should display the range up to the first non-empty line
5904                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5905                        }
5906
5907                        result.push(indent)
5908                    }
5909                }
5910                cmp::Ordering::Greater => {
5911                    for next_depth in current_depth..depth {
5912                        indent_stack.push(IndentGuide {
5913                            buffer_id: buffer.remote_id(),
5914                            start_row: first_row,
5915                            end_row: last_row,
5916                            depth: next_depth,
5917                            tab_size,
5918                            settings: settings.indent_guides,
5919                        });
5920                    }
5921                }
5922                _ => {}
5923            }
5924
5925            for indent in indent_stack.iter_mut() {
5926                indent.end_row = last_row;
5927            }
5928        }
5929
5930        result.extend(indent_stack);
5931        result.into_iter()
5932    }
5933
5934    pub fn trailing_excerpt_update_count(&self) -> usize {
5935        self.trailing_excerpt_update_count
5936    }
5937
5938    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5939        self.point_to_buffer_offset(point)
5940            .and_then(|(buffer, _)| buffer.file())
5941    }
5942
5943    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5944        self.point_to_buffer_offset(point)
5945            .and_then(|(buffer, offset)| buffer.language_at(offset))
5946    }
5947
5948    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5949        self.excerpts
5950            .first()
5951            .map(|excerpt| &excerpt.buffer)
5952            .map(|buffer| {
5953                language_settings(
5954                    buffer.language().map(|language| language.name()),
5955                    buffer.file(),
5956                    cx,
5957                )
5958            })
5959            .unwrap_or_else(move || self.language_settings_at(0, cx))
5960    }
5961
5962    pub fn language_settings_at<'a, T: ToOffset>(
5963        &'a self,
5964        point: T,
5965        cx: &'a App,
5966    ) -> Cow<'a, LanguageSettings> {
5967        let mut language = None;
5968        let mut file = None;
5969        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5970            language = buffer.language_at(offset);
5971            file = buffer.file();
5972        }
5973        language_settings(language.map(|l| l.name()), file, cx)
5974    }
5975
5976    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5977        self.point_to_buffer_offset(point)
5978            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5979    }
5980
5981    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5982        self.point_to_buffer_offset(point)
5983            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5984            .unwrap_or_default()
5985    }
5986
5987    pub fn language_indent_size_at<T: ToOffset>(
5988        &self,
5989        position: T,
5990        cx: &App,
5991    ) -> Option<IndentSize> {
5992        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5993        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5994    }
5995
5996    pub fn is_dirty(&self) -> bool {
5997        self.is_dirty
5998    }
5999
6000    pub fn has_deleted_file(&self) -> bool {
6001        self.has_deleted_file
6002    }
6003
6004    pub fn has_conflict(&self) -> bool {
6005        self.has_conflict
6006    }
6007
6008    pub fn has_diagnostics(&self) -> bool {
6009        self.excerpts
6010            .iter()
6011            .any(|excerpt| excerpt.buffer.has_diagnostics())
6012    }
6013
6014    pub fn diagnostic_group(
6015        &self,
6016        buffer_id: BufferId,
6017        group_id: usize,
6018    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
6019        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, range| {
6020            if buffer.remote_id() != buffer_id {
6021                return None;
6022            };
6023            Some(
6024                buffer
6025                    .diagnostics_in_range(range, false)
6026                    .filter(move |diagnostic| diagnostic.diagnostic.group_id == group_id)
6027                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
6028            )
6029        })
6030        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6031    }
6032
6033    pub fn diagnostics_in_range<'a, T>(
6034        &'a self,
6035        range: Range<T>,
6036    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
6037    where
6038        T: 'a
6039            + text::ToOffset
6040            + text::FromAnchor
6041            + TextDimension
6042            + Ord
6043            + Sub<T, Output = T>
6044            + fmt::Debug,
6045    {
6046        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6047            Some(
6048                buffer
6049                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6050                    .map(|entry| (entry.range, entry.diagnostic)),
6051            )
6052        })
6053        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
6054    }
6055
6056    pub fn diagnostics_with_buffer_ids_in_range<'a, T>(
6057        &'a self,
6058        range: Range<T>,
6059    ) -> impl Iterator<Item = (BufferId, DiagnosticEntry<T>)> + 'a
6060    where
6061        T: 'a
6062            + text::ToOffset
6063            + text::FromAnchor
6064            + TextDimension
6065            + Ord
6066            + Sub<T, Output = T>
6067            + fmt::Debug,
6068    {
6069        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
6070            Some(
6071                buffer
6072                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
6073                    .map(|entry| (entry.range, entry.diagnostic)),
6074            )
6075        })
6076        .map(|(range, diagnostic, b)| (b.buffer_id, DiagnosticEntry { diagnostic, range }))
6077    }
6078
6079    pub fn syntax_ancestor<T: ToOffset>(
6080        &self,
6081        range: Range<T>,
6082    ) -> Option<(tree_sitter::Node<'_>, MultiOrSingleBufferOffsetRange)> {
6083        let range = range.start.to_offset(self)..range.end.to_offset(self);
6084        let mut excerpt = self.excerpt_containing(range.clone())?;
6085        let node = excerpt
6086            .buffer()
6087            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
6088        let node_range = node.byte_range();
6089        let range = if excerpt.contains_buffer_range(node_range.clone()) {
6090            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
6091        } else {
6092            MultiOrSingleBufferOffsetRange::Single(node_range)
6093        };
6094        Some((node, range))
6095    }
6096
6097    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
6098        let (excerpt_id, _, buffer) = self.as_singleton()?;
6099        let outline = buffer.outline(theme)?;
6100        Some(Outline::new(
6101            outline
6102                .items
6103                .into_iter()
6104                .flat_map(|item| {
6105                    Some(OutlineItem {
6106                        depth: item.depth,
6107                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
6108                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
6109                        text: item.text,
6110                        highlight_ranges: item.highlight_ranges,
6111                        name_ranges: item.name_ranges,
6112                        body_range: item.body_range.and_then(|body_range| {
6113                            Some(
6114                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
6115                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
6116                            )
6117                        }),
6118                        annotation_range: item.annotation_range.and_then(|annotation_range| {
6119                            Some(
6120                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
6121                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
6122                            )
6123                        }),
6124                    })
6125                })
6126                .collect(),
6127        ))
6128    }
6129
6130    pub fn symbols_containing<T: ToOffset>(
6131        &self,
6132        offset: T,
6133        theme: Option<&SyntaxTheme>,
6134    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6135        let anchor = self.anchor_before(offset);
6136        let excerpt_id = anchor.excerpt_id;
6137        let excerpt = self.excerpt(excerpt_id)?;
6138        Some((
6139            excerpt.buffer_id,
6140            excerpt
6141                .buffer
6142                .symbols_containing(anchor.text_anchor, theme)
6143                .into_iter()
6144                .flatten()
6145                .flat_map(|item| {
6146                    Some(OutlineItem {
6147                        depth: item.depth,
6148                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6149                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6150                        text: item.text,
6151                        highlight_ranges: item.highlight_ranges,
6152                        name_ranges: item.name_ranges,
6153                        body_range: item.body_range.and_then(|body_range| {
6154                            Some(
6155                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6156                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6157                            )
6158                        }),
6159                        annotation_range: item.annotation_range.and_then(|body_range| {
6160                            Some(
6161                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6162                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6163                            )
6164                        }),
6165                    })
6166                })
6167                .collect(),
6168        ))
6169    }
6170
6171    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6172        if id == ExcerptId::min() {
6173            Locator::min_ref()
6174        } else if id == ExcerptId::max() {
6175            Locator::max_ref()
6176        } else {
6177            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6178            cursor.seek(&id, Bias::Left);
6179            if let Some(entry) = cursor.item()
6180                && entry.id == id
6181            {
6182                return &entry.locator;
6183            }
6184            panic!("invalid excerpt id {id:?}")
6185        }
6186    }
6187
6188    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6189    fn excerpt_locators_for_ids(
6190        &self,
6191        ids: impl IntoIterator<Item = ExcerptId>,
6192    ) -> SmallVec<[Locator; 1]> {
6193        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6194        sorted_ids.sort_unstable();
6195        let mut locators = SmallVec::new();
6196
6197        while sorted_ids.last() == Some(&ExcerptId::max()) {
6198            sorted_ids.pop();
6199            if let Some(mapping) = self.excerpt_ids.last() {
6200                locators.push(mapping.locator.clone());
6201            }
6202        }
6203
6204        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6205        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6206            sorted_ids.next();
6207            if let Some(mapping) = self.excerpt_ids.first() {
6208                locators.push(mapping.locator.clone());
6209            }
6210        }
6211
6212        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6213        for id in sorted_ids {
6214            if cursor.seek_forward(&id, Bias::Left) {
6215                locators.push(cursor.item().unwrap().locator.clone());
6216            } else {
6217                panic!("invalid excerpt id {:?}", id);
6218            }
6219        }
6220
6221        locators.sort_unstable();
6222        locators
6223    }
6224
6225    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6226        Some(self.excerpt(excerpt_id)?.buffer_id)
6227    }
6228
6229    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6230        Some(&self.excerpt(excerpt_id)?.buffer)
6231    }
6232
6233    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6234        let mut cursor = self
6235            .excerpts
6236            .cursor::<Dimensions<Option<&Locator>, ExcerptDimension<Point>>>(&());
6237        let locator = self.excerpt_locator_for_id(excerpt_id);
6238        if cursor.seek(&Some(locator), Bias::Left) {
6239            let start = cursor.start().1.clone();
6240            let end = cursor.end().1;
6241            let mut diff_transforms = self
6242                .diff_transforms
6243                .cursor::<Dimensions<ExcerptDimension<Point>, OutputDimension<Point>>>(&());
6244            diff_transforms.seek(&start, Bias::Left);
6245            let overshoot = start.0 - diff_transforms.start().0.0;
6246            let start = diff_transforms.start().1.0 + overshoot;
6247            diff_transforms.seek(&end, Bias::Right);
6248            let overshoot = end.0 - diff_transforms.start().0.0;
6249            let end = diff_transforms.start().1.0 + overshoot;
6250            Some(start..end)
6251        } else {
6252            None
6253        }
6254    }
6255
6256    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6257        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6258        let locator = self.excerpt_locator_for_id(excerpt_id);
6259        if cursor.seek(&Some(locator), Bias::Left)
6260            && let Some(excerpt) = cursor.item()
6261        {
6262            return Some(excerpt.range.context.clone());
6263        }
6264        None
6265    }
6266
6267    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6268        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6269        let locator = self.excerpt_locator_for_id(excerpt_id);
6270        cursor.seek(&Some(locator), Bias::Left);
6271        if let Some(excerpt) = cursor.item()
6272            && excerpt.id == excerpt_id
6273        {
6274            return Some(excerpt);
6275        }
6276        None
6277    }
6278
6279    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6280    pub fn excerpt_containing<T: ToOffset>(
6281        &self,
6282        range: Range<T>,
6283    ) -> Option<MultiBufferExcerpt<'_>> {
6284        let range = range.start.to_offset(self)..range.end.to_offset(self);
6285        let mut cursor = self.cursor::<usize>();
6286        cursor.seek(&range.start);
6287
6288        let start_excerpt = cursor.excerpt()?;
6289        if range.end != range.start {
6290            cursor.seek_forward(&range.end);
6291            if cursor.excerpt()?.id != start_excerpt.id {
6292                return None;
6293            }
6294        }
6295
6296        cursor.seek_to_start_of_current_excerpt();
6297        let region = cursor.region()?;
6298        let offset = region.range.start;
6299        let buffer_offset = start_excerpt.buffer_start_offset();
6300        let excerpt_offset = cursor.excerpts.start().clone();
6301        Some(MultiBufferExcerpt {
6302            diff_transforms: cursor.diff_transforms,
6303            excerpt: start_excerpt,
6304            offset,
6305            buffer_offset,
6306            excerpt_offset,
6307        })
6308    }
6309
6310    pub fn buffer_id_for_anchor(&self, anchor: Anchor) -> Option<BufferId> {
6311        if let Some(id) = anchor.buffer_id {
6312            return Some(id);
6313        }
6314        let excerpt = self.excerpt_containing(anchor..anchor)?;
6315        Some(excerpt.buffer_id())
6316    }
6317
6318    pub fn selections_in_range<'a>(
6319        &'a self,
6320        range: &'a Range<Anchor>,
6321        include_local: bool,
6322    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6323        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6324        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6325        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6326        cursor.seek(start_locator, Bias::Left);
6327        cursor
6328            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6329            .flat_map(move |excerpt| {
6330                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6331                if excerpt.id == range.start.excerpt_id {
6332                    query_range.start = range.start.text_anchor;
6333                }
6334                if excerpt.id == range.end.excerpt_id {
6335                    query_range.end = range.end.text_anchor;
6336                }
6337
6338                excerpt
6339                    .buffer
6340                    .selections_in_range(query_range, include_local)
6341                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6342                        selections.map(move |selection| {
6343                            let mut start = Anchor {
6344                                buffer_id: Some(excerpt.buffer_id),
6345                                excerpt_id: excerpt.id,
6346                                text_anchor: selection.start,
6347                                diff_base_anchor: None,
6348                            };
6349                            let mut end = Anchor {
6350                                buffer_id: Some(excerpt.buffer_id),
6351                                excerpt_id: excerpt.id,
6352                                text_anchor: selection.end,
6353                                diff_base_anchor: None,
6354                            };
6355                            if range.start.cmp(&start, self).is_gt() {
6356                                start = range.start;
6357                            }
6358                            if range.end.cmp(&end, self).is_lt() {
6359                                end = range.end;
6360                            }
6361
6362                            (
6363                                replica_id,
6364                                line_mode,
6365                                cursor_shape,
6366                                Selection {
6367                                    id: selection.id,
6368                                    start,
6369                                    end,
6370                                    reversed: selection.reversed,
6371                                    goal: selection.goal,
6372                                },
6373                            )
6374                        })
6375                    })
6376            })
6377    }
6378
6379    pub fn show_headers(&self) -> bool {
6380        self.show_headers
6381    }
6382
6383    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6384        self.diffs.get(&buffer_id)
6385    }
6386}
6387
6388#[cfg(any(test, feature = "test-support"))]
6389impl MultiBufferSnapshot {
6390    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6391        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6392        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6393        start..end
6394    }
6395
6396    #[cfg(any(test, feature = "test-support"))]
6397    fn check_invariants(&self) {
6398        let excerpts = self.excerpts.items(&());
6399        let excerpt_ids = self.excerpt_ids.items(&());
6400
6401        for (ix, excerpt) in excerpts.iter().enumerate() {
6402            if ix == 0 {
6403                if excerpt.locator <= Locator::min() {
6404                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6405                }
6406            } else if excerpt.locator <= excerpts[ix - 1].locator {
6407                panic!("excerpts are out-of-order: {:?}", excerpts);
6408            }
6409        }
6410
6411        for (ix, entry) in excerpt_ids.iter().enumerate() {
6412            if ix == 0 {
6413                if entry.id.cmp(&ExcerptId::min(), self).is_le() {
6414                    panic!("invalid first excerpt id {:?}", entry.id);
6415                }
6416            } else if entry.id <= excerpt_ids[ix - 1].id {
6417                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6418            }
6419        }
6420
6421        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6422            panic!(
6423                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6424                self.excerpts.summary().text.len,
6425                self.diff_transforms.summary().input,
6426                self.diff_transforms.items(&()),
6427            );
6428        }
6429
6430        let mut prev_transform: Option<&DiffTransform> = None;
6431        for item in self.diff_transforms.iter() {
6432            if let DiffTransform::BufferContent {
6433                summary,
6434                inserted_hunk_info,
6435            } = item
6436            {
6437                if let Some(DiffTransform::BufferContent {
6438                    inserted_hunk_info: prev_inserted_hunk_info,
6439                    ..
6440                }) = prev_transform
6441                    && *inserted_hunk_info == *prev_inserted_hunk_info
6442                {
6443                    panic!(
6444                        "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6445                        self.diff_transforms.items(&())
6446                    );
6447                }
6448                if summary.len == 0 && !self.is_empty() {
6449                    panic!("empty buffer content transform");
6450                }
6451            }
6452            prev_transform = Some(item);
6453        }
6454    }
6455}
6456
6457impl<'a, D> MultiBufferCursor<'a, D>
6458where
6459    D: TextDimension + Ord + Sub<D, Output = D>,
6460{
6461    fn seek(&mut self, position: &D) {
6462        self.cached_region.take();
6463        self.diff_transforms
6464            .seek(&OutputDimension(*position), Bias::Right);
6465        if self.diff_transforms.item().is_none()
6466            && *position == self.diff_transforms.start().output_dimension.0
6467        {
6468            self.diff_transforms.prev();
6469        }
6470
6471        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6472        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6473            let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6474            excerpt_position.add_assign(&overshoot);
6475        }
6476
6477        self.excerpts
6478            .seek(&ExcerptDimension(excerpt_position), Bias::Right);
6479        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6480            self.excerpts.prev();
6481        }
6482    }
6483
6484    fn seek_forward(&mut self, position: &D) {
6485        self.cached_region.take();
6486        self.diff_transforms
6487            .seek_forward(&OutputDimension(*position), Bias::Right);
6488        if self.diff_transforms.item().is_none()
6489            && *position == self.diff_transforms.start().output_dimension.0
6490        {
6491            self.diff_transforms.prev();
6492        }
6493
6494        let overshoot = *position - self.diff_transforms.start().output_dimension.0;
6495        let mut excerpt_position = self.diff_transforms.start().excerpt_dimension.0;
6496        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6497            excerpt_position.add_assign(&overshoot);
6498        }
6499
6500        self.excerpts
6501            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right);
6502        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6503            self.excerpts.prev();
6504        }
6505    }
6506
6507    fn next_excerpt(&mut self) {
6508        self.excerpts.next();
6509        self.seek_to_start_of_current_excerpt();
6510    }
6511
6512    fn prev_excerpt(&mut self) {
6513        self.excerpts.prev();
6514        self.seek_to_start_of_current_excerpt();
6515    }
6516
6517    fn seek_to_start_of_current_excerpt(&mut self) {
6518        self.cached_region.take();
6519        self.diff_transforms.seek(self.excerpts.start(), Bias::Left);
6520        if self.diff_transforms.end().excerpt_dimension == *self.excerpts.start()
6521            && self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6522            && self.diff_transforms.next_item().is_some()
6523        {
6524            self.diff_transforms.next();
6525        }
6526    }
6527
6528    fn next(&mut self) {
6529        self.cached_region.take();
6530        match self
6531            .diff_transforms
6532            .end()
6533            .excerpt_dimension
6534            .cmp(&self.excerpts.end())
6535        {
6536            cmp::Ordering::Less => self.diff_transforms.next(),
6537            cmp::Ordering::Greater => self.excerpts.next(),
6538            cmp::Ordering::Equal => {
6539                self.diff_transforms.next();
6540                if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6541                    || self.diff_transforms.item().is_none()
6542                {
6543                    self.excerpts.next();
6544                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6545                    self.diff_transforms.item()
6546                    && self
6547                        .excerpts
6548                        .item()
6549                        .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id)
6550                {
6551                    self.excerpts.next();
6552                }
6553            }
6554        }
6555    }
6556
6557    fn prev(&mut self) {
6558        self.cached_region.take();
6559        match self
6560            .diff_transforms
6561            .start()
6562            .excerpt_dimension
6563            .cmp(self.excerpts.start())
6564        {
6565            cmp::Ordering::Less => self.excerpts.prev(),
6566            cmp::Ordering::Greater => self.diff_transforms.prev(),
6567            cmp::Ordering::Equal => {
6568                self.diff_transforms.prev();
6569                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start()
6570                    || self.diff_transforms.item().is_none()
6571                {
6572                    self.excerpts.prev();
6573                }
6574            }
6575        }
6576    }
6577
6578    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6579        if self.cached_region.is_none() {
6580            self.cached_region = self.build_region();
6581        }
6582        self.cached_region.clone()
6583    }
6584
6585    fn is_at_start_of_excerpt(&mut self) -> bool {
6586        if self.diff_transforms.start().excerpt_dimension > *self.excerpts.start() {
6587            return false;
6588        } else if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6589            return true;
6590        }
6591
6592        self.diff_transforms.prev();
6593        let prev_transform = self.diff_transforms.item();
6594        self.diff_transforms.next();
6595
6596        prev_transform.is_none_or(|next_transform| {
6597            matches!(next_transform, DiffTransform::BufferContent { .. })
6598        })
6599    }
6600
6601    fn is_at_end_of_excerpt(&mut self) -> bool {
6602        if self.diff_transforms.end().excerpt_dimension < self.excerpts.end() {
6603            return false;
6604        } else if self.diff_transforms.end().excerpt_dimension > self.excerpts.end()
6605            || self.diff_transforms.item().is_none()
6606        {
6607            return true;
6608        }
6609
6610        let next_transform = self.diff_transforms.next_item();
6611        next_transform.is_none_or(|next_transform| match next_transform {
6612            DiffTransform::BufferContent { .. } => true,
6613            DiffTransform::DeletedHunk { hunk_info, .. } => self
6614                .excerpts
6615                .item()
6616                .is_some_and(|excerpt| excerpt.id != hunk_info.excerpt_id),
6617        })
6618    }
6619
6620    fn main_buffer_position(&self) -> Option<D> {
6621        let excerpt = self.excerpts.item()?;
6622        let buffer = &excerpt.buffer;
6623        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6624        let mut buffer_start = buffer_context_start;
6625        let overshoot = self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6626        buffer_start.add_assign(&overshoot);
6627        Some(buffer_start)
6628    }
6629
6630    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6631        let excerpt = self.excerpts.item()?;
6632        match self.diff_transforms.item()? {
6633            DiffTransform::DeletedHunk {
6634                buffer_id,
6635                base_text_byte_range,
6636                has_trailing_newline,
6637                hunk_info,
6638                ..
6639            } => {
6640                let diff = self.diffs.get(buffer_id)?;
6641                let buffer = diff.base_text();
6642                let mut rope_cursor = buffer.as_rope().cursor(0);
6643                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6644                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6645                let mut buffer_end = buffer_start;
6646                buffer_end.add_assign(&buffer_range_len);
6647                let start = self.diff_transforms.start().output_dimension.0;
6648                let end = self.diff_transforms.end().output_dimension.0;
6649                Some(MultiBufferRegion {
6650                    buffer,
6651                    excerpt,
6652                    has_trailing_newline: *has_trailing_newline,
6653                    is_main_buffer: false,
6654                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6655                        hunk_info.hunk_secondary_status,
6656                    )),
6657                    buffer_range: buffer_start..buffer_end,
6658                    range: start..end,
6659                })
6660            }
6661            DiffTransform::BufferContent {
6662                inserted_hunk_info, ..
6663            } => {
6664                let buffer = &excerpt.buffer;
6665                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6666
6667                let mut start = self.diff_transforms.start().output_dimension.0;
6668                let mut buffer_start = buffer_context_start;
6669                if self.diff_transforms.start().excerpt_dimension < *self.excerpts.start() {
6670                    let overshoot =
6671                        self.excerpts.start().0 - self.diff_transforms.start().excerpt_dimension.0;
6672                    start.add_assign(&overshoot);
6673                } else {
6674                    let overshoot =
6675                        self.diff_transforms.start().excerpt_dimension.0 - self.excerpts.start().0;
6676                    buffer_start.add_assign(&overshoot);
6677                }
6678
6679                let mut end;
6680                let mut buffer_end;
6681                let has_trailing_newline;
6682                if self.diff_transforms.end().excerpt_dimension.0 < self.excerpts.end().0 {
6683                    let overshoot =
6684                        self.diff_transforms.end().excerpt_dimension.0 - self.excerpts.start().0;
6685                    end = self.diff_transforms.end().output_dimension.0;
6686                    buffer_end = buffer_context_start;
6687                    buffer_end.add_assign(&overshoot);
6688                    has_trailing_newline = false;
6689                } else {
6690                    let overshoot =
6691                        self.excerpts.end().0 - self.diff_transforms.start().excerpt_dimension.0;
6692                    end = self.diff_transforms.start().output_dimension.0;
6693                    end.add_assign(&overshoot);
6694                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6695                    has_trailing_newline = excerpt.has_trailing_newline;
6696                };
6697
6698                Some(MultiBufferRegion {
6699                    buffer,
6700                    excerpt,
6701                    has_trailing_newline,
6702                    is_main_buffer: true,
6703                    diff_hunk_status: inserted_hunk_info
6704                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6705                    buffer_range: buffer_start..buffer_end,
6706                    range: start..end,
6707                })
6708            }
6709        }
6710    }
6711
6712    fn excerpt(&self) -> Option<&'a Excerpt> {
6713        self.excerpts.item()
6714    }
6715}
6716
6717impl History {
6718    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6719        self.transaction_depth += 1;
6720        if self.transaction_depth == 1 {
6721            let id = self.next_transaction_id.tick();
6722            self.undo_stack.push(Transaction {
6723                id,
6724                buffer_transactions: Default::default(),
6725                first_edit_at: now,
6726                last_edit_at: now,
6727                suppress_grouping: false,
6728            });
6729            Some(id)
6730        } else {
6731            None
6732        }
6733    }
6734
6735    fn end_transaction(
6736        &mut self,
6737        now: Instant,
6738        buffer_transactions: HashMap<BufferId, TransactionId>,
6739    ) -> bool {
6740        assert_ne!(self.transaction_depth, 0);
6741        self.transaction_depth -= 1;
6742        if self.transaction_depth == 0 {
6743            if buffer_transactions.is_empty() {
6744                self.undo_stack.pop();
6745                false
6746            } else {
6747                self.redo_stack.clear();
6748                let transaction = self.undo_stack.last_mut().unwrap();
6749                transaction.last_edit_at = now;
6750                for (buffer_id, transaction_id) in buffer_transactions {
6751                    transaction
6752                        .buffer_transactions
6753                        .entry(buffer_id)
6754                        .or_insert(transaction_id);
6755                }
6756                true
6757            }
6758        } else {
6759            false
6760        }
6761    }
6762
6763    fn push_transaction<'a, T>(
6764        &mut self,
6765        buffer_transactions: T,
6766        now: Instant,
6767        cx: &Context<MultiBuffer>,
6768    ) where
6769        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6770    {
6771        assert_eq!(self.transaction_depth, 0);
6772        let transaction = Transaction {
6773            id: self.next_transaction_id.tick(),
6774            buffer_transactions: buffer_transactions
6775                .into_iter()
6776                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6777                .collect(),
6778            first_edit_at: now,
6779            last_edit_at: now,
6780            suppress_grouping: false,
6781        };
6782        if !transaction.buffer_transactions.is_empty() {
6783            self.undo_stack.push(transaction);
6784            self.redo_stack.clear();
6785        }
6786    }
6787
6788    fn finalize_last_transaction(&mut self) {
6789        if let Some(transaction) = self.undo_stack.last_mut() {
6790            transaction.suppress_grouping = true;
6791        }
6792    }
6793
6794    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6795        if let Some(ix) = self
6796            .undo_stack
6797            .iter()
6798            .rposition(|transaction| transaction.id == transaction_id)
6799        {
6800            Some(self.undo_stack.remove(ix))
6801        } else if let Some(ix) = self
6802            .redo_stack
6803            .iter()
6804            .rposition(|transaction| transaction.id == transaction_id)
6805        {
6806            Some(self.redo_stack.remove(ix))
6807        } else {
6808            None
6809        }
6810    }
6811
6812    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6813        self.undo_stack
6814            .iter()
6815            .find(|transaction| transaction.id == transaction_id)
6816            .or_else(|| {
6817                self.redo_stack
6818                    .iter()
6819                    .find(|transaction| transaction.id == transaction_id)
6820            })
6821    }
6822
6823    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6824        self.undo_stack
6825            .iter_mut()
6826            .find(|transaction| transaction.id == transaction_id)
6827            .or_else(|| {
6828                self.redo_stack
6829                    .iter_mut()
6830                    .find(|transaction| transaction.id == transaction_id)
6831            })
6832    }
6833
6834    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6835        assert_eq!(self.transaction_depth, 0);
6836        if let Some(transaction) = self.undo_stack.pop() {
6837            self.redo_stack.push(transaction);
6838            self.redo_stack.last_mut()
6839        } else {
6840            None
6841        }
6842    }
6843
6844    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6845        assert_eq!(self.transaction_depth, 0);
6846        if let Some(transaction) = self.redo_stack.pop() {
6847            self.undo_stack.push(transaction);
6848            self.undo_stack.last_mut()
6849        } else {
6850            None
6851        }
6852    }
6853
6854    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6855        let ix = self
6856            .undo_stack
6857            .iter()
6858            .rposition(|transaction| transaction.id == transaction_id)?;
6859        let transaction = self.undo_stack.remove(ix);
6860        self.redo_stack.push(transaction);
6861        self.redo_stack.last()
6862    }
6863
6864    fn group(&mut self) -> Option<TransactionId> {
6865        let mut count = 0;
6866        let mut transactions = self.undo_stack.iter();
6867        if let Some(mut transaction) = transactions.next_back() {
6868            while let Some(prev_transaction) = transactions.next_back() {
6869                if !prev_transaction.suppress_grouping
6870                    && transaction.first_edit_at - prev_transaction.last_edit_at
6871                        <= self.group_interval
6872                {
6873                    transaction = prev_transaction;
6874                    count += 1;
6875                } else {
6876                    break;
6877                }
6878            }
6879        }
6880        self.group_trailing(count)
6881    }
6882
6883    fn group_until(&mut self, transaction_id: TransactionId) {
6884        let mut count = 0;
6885        for transaction in self.undo_stack.iter().rev() {
6886            if transaction.id == transaction_id {
6887                self.group_trailing(count);
6888                break;
6889            } else if transaction.suppress_grouping {
6890                break;
6891            } else {
6892                count += 1;
6893            }
6894        }
6895    }
6896
6897    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6898        let new_len = self.undo_stack.len() - n;
6899        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6900        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6901            if let Some(transaction) = transactions_to_merge.last() {
6902                last_transaction.last_edit_at = transaction.last_edit_at;
6903            }
6904            for to_merge in transactions_to_merge {
6905                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6906                    last_transaction
6907                        .buffer_transactions
6908                        .entry(*buffer_id)
6909                        .or_insert(*transaction_id);
6910                }
6911            }
6912        }
6913
6914        self.undo_stack.truncate(new_len);
6915        self.undo_stack.last().map(|t| t.id)
6916    }
6917}
6918
6919impl Excerpt {
6920    fn new(
6921        id: ExcerptId,
6922        locator: Locator,
6923        buffer_id: BufferId,
6924        buffer: BufferSnapshot,
6925        range: ExcerptRange<text::Anchor>,
6926        has_trailing_newline: bool,
6927    ) -> Self {
6928        Excerpt {
6929            id,
6930            locator,
6931            max_buffer_row: range.context.end.to_point(&buffer).row,
6932            text_summary: buffer
6933                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6934            buffer_id,
6935            buffer,
6936            range,
6937            has_trailing_newline,
6938        }
6939    }
6940
6941    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks<'_> {
6942        let content_start = self.range.context.start.to_offset(&self.buffer);
6943        let chunks_start = content_start + range.start;
6944        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6945
6946        let footer_height = if self.has_trailing_newline
6947            && range.start <= self.text_summary.len
6948            && range.end > self.text_summary.len
6949        {
6950            1
6951        } else {
6952            0
6953        };
6954
6955        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6956
6957        ExcerptChunks {
6958            excerpt_id: self.id,
6959            content_chunks,
6960            footer_height,
6961        }
6962    }
6963
6964    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6965        let content_start = self.range.context.start.to_offset(&self.buffer);
6966        let chunks_start = content_start + range.start;
6967        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6968        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6969        excerpt_chunks.footer_height = if self.has_trailing_newline
6970            && range.start <= self.text_summary.len
6971            && range.end > self.text_summary.len
6972        {
6973            1
6974        } else {
6975            0
6976        };
6977    }
6978
6979    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6980        if text_anchor
6981            .cmp(&self.range.context.start, &self.buffer)
6982            .is_lt()
6983        {
6984            self.range.context.start
6985        } else if text_anchor
6986            .cmp(&self.range.context.end, &self.buffer)
6987            .is_gt()
6988        {
6989            self.range.context.end
6990        } else {
6991            text_anchor
6992        }
6993    }
6994
6995    fn contains(&self, anchor: &Anchor) -> bool {
6996        (anchor.buffer_id == None || anchor.buffer_id == Some(self.buffer_id))
6997            && self
6998                .range
6999                .context
7000                .start
7001                .cmp(&anchor.text_anchor, &self.buffer)
7002                .is_le()
7003            && self
7004                .range
7005                .context
7006                .end
7007                .cmp(&anchor.text_anchor, &self.buffer)
7008                .is_ge()
7009    }
7010
7011    /// The [`Excerpt`]'s start offset in its [`Buffer`]
7012    fn buffer_start_offset(&self) -> usize {
7013        self.range.context.start.to_offset(&self.buffer)
7014    }
7015
7016    /// The [`Excerpt`]'s end offset in its [`Buffer`]
7017    fn buffer_end_offset(&self) -> usize {
7018        self.buffer_start_offset() + self.text_summary.len
7019    }
7020}
7021
7022impl<'a> MultiBufferExcerpt<'a> {
7023    pub fn id(&self) -> ExcerptId {
7024        self.excerpt.id
7025    }
7026
7027    pub fn buffer_id(&self) -> BufferId {
7028        self.excerpt.buffer_id
7029    }
7030
7031    pub fn start_anchor(&self) -> Anchor {
7032        Anchor {
7033            buffer_id: Some(self.excerpt.buffer_id),
7034            excerpt_id: self.excerpt.id,
7035            text_anchor: self.excerpt.range.context.start,
7036            diff_base_anchor: None,
7037        }
7038    }
7039
7040    pub fn end_anchor(&self) -> Anchor {
7041        Anchor {
7042            buffer_id: Some(self.excerpt.buffer_id),
7043            excerpt_id: self.excerpt.id,
7044            text_anchor: self.excerpt.range.context.end,
7045            diff_base_anchor: None,
7046        }
7047    }
7048
7049    pub fn buffer(&self) -> &'a BufferSnapshot {
7050        &self.excerpt.buffer
7051    }
7052
7053    pub fn buffer_range(&self) -> Range<usize> {
7054        self.buffer_offset
7055            ..self
7056                .excerpt
7057                .range
7058                .context
7059                .end
7060                .to_offset(&self.excerpt.buffer.text)
7061    }
7062
7063    pub fn start_offset(&self) -> usize {
7064        self.offset
7065    }
7066
7067    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
7068    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
7069        self.map_range_to_buffer(offset..offset).start
7070    }
7071
7072    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
7073    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
7074        self.diff_transforms
7075            .seek(&OutputDimension(range.start), Bias::Right);
7076        let start = self.map_offset_to_buffer_internal(range.start);
7077        let end = if range.end > range.start {
7078            self.diff_transforms
7079                .seek_forward(&OutputDimension(range.end), Bias::Right);
7080            self.map_offset_to_buffer_internal(range.end)
7081        } else {
7082            start
7083        };
7084        start..end
7085    }
7086
7087    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
7088        let mut excerpt_offset = self.diff_transforms.start().excerpt_dimension.clone();
7089        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7090            excerpt_offset.0 += offset - self.diff_transforms.start().output_dimension.0;
7091        };
7092        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
7093        self.buffer_offset + offset_in_excerpt
7094    }
7095
7096    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
7097    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
7098        self.map_range_from_buffer(buffer_offset..buffer_offset)
7099            .start
7100    }
7101
7102    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
7103    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
7104        if buffer_range.start < self.buffer_offset {
7105            log::warn!(
7106                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7107            );
7108            return buffer_range;
7109        }
7110        let overshoot = buffer_range.start - self.buffer_offset;
7111        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7112        self.diff_transforms.seek(&excerpt_offset, Bias::Right);
7113        if excerpt_offset.0 < self.diff_transforms.start().excerpt_dimension.0 {
7114            log::warn!(
7115                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
7116            );
7117            return buffer_range;
7118        }
7119        let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7120        let start = self.diff_transforms.start().output_dimension.0 + overshoot;
7121
7122        let end = if buffer_range.end > buffer_range.start {
7123            let overshoot = buffer_range.end - self.buffer_offset;
7124            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
7125            self.diff_transforms
7126                .seek_forward(&excerpt_offset, Bias::Right);
7127            let overshoot = excerpt_offset.0 - self.diff_transforms.start().excerpt_dimension.0;
7128            self.diff_transforms.start().output_dimension.0 + overshoot
7129        } else {
7130            start
7131        };
7132
7133        start..end
7134    }
7135
7136    /// Returns true if the entirety of the given range is in the buffer's excerpt
7137    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
7138        range.start >= self.excerpt.buffer_start_offset()
7139            && range.end <= self.excerpt.buffer_end_offset()
7140    }
7141
7142    pub fn max_buffer_row(&self) -> u32 {
7143        self.excerpt.max_buffer_row
7144    }
7145}
7146
7147impl ExcerptId {
7148    pub fn min() -> Self {
7149        Self(0)
7150    }
7151
7152    pub fn max() -> Self {
7153        Self(usize::MAX)
7154    }
7155
7156    pub fn to_proto(self) -> u64 {
7157        self.0 as _
7158    }
7159
7160    pub fn from_proto(proto: u64) -> Self {
7161        Self(proto as _)
7162    }
7163
7164    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7165        let a = snapshot.excerpt_locator_for_id(*self);
7166        let b = snapshot.excerpt_locator_for_id(*other);
7167        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7168    }
7169}
7170
7171impl From<ExcerptId> for usize {
7172    fn from(val: ExcerptId) -> Self {
7173        val.0
7174    }
7175}
7176
7177impl fmt::Debug for Excerpt {
7178    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7179        f.debug_struct("Excerpt")
7180            .field("id", &self.id)
7181            .field("locator", &self.locator)
7182            .field("buffer_id", &self.buffer_id)
7183            .field("range", &self.range)
7184            .field("text_summary", &self.text_summary)
7185            .field("has_trailing_newline", &self.has_trailing_newline)
7186            .finish()
7187    }
7188}
7189
7190impl sum_tree::Item for Excerpt {
7191    type Summary = ExcerptSummary;
7192
7193    fn summary(&self, _cx: &()) -> Self::Summary {
7194        let mut text = self.text_summary;
7195        if self.has_trailing_newline {
7196            text += TextSummary::from("\n");
7197        }
7198        ExcerptSummary {
7199            excerpt_id: self.id,
7200            excerpt_locator: self.locator.clone(),
7201            widest_line_number: self.max_buffer_row,
7202            text,
7203        }
7204    }
7205}
7206
7207impl sum_tree::Item for ExcerptIdMapping {
7208    type Summary = ExcerptId;
7209
7210    fn summary(&self, _cx: &()) -> Self::Summary {
7211        self.id
7212    }
7213}
7214
7215impl sum_tree::KeyedItem for ExcerptIdMapping {
7216    type Key = ExcerptId;
7217
7218    fn key(&self) -> Self::Key {
7219        self.id
7220    }
7221}
7222
7223impl DiffTransform {
7224    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7225        match self {
7226            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7227            DiffTransform::BufferContent {
7228                inserted_hunk_info, ..
7229            } => *inserted_hunk_info,
7230        }
7231    }
7232}
7233
7234impl sum_tree::Item for DiffTransform {
7235    type Summary = DiffTransformSummary;
7236
7237    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7238        match self {
7239            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7240                input: *summary,
7241                output: *summary,
7242            },
7243            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7244                input: TextSummary::default(),
7245                output: *summary,
7246            },
7247        }
7248    }
7249}
7250
7251impl DiffTransformSummary {
7252    fn excerpt_len(&self) -> ExcerptOffset {
7253        ExcerptOffset::new(self.input.len)
7254    }
7255}
7256
7257impl sum_tree::Summary for DiffTransformSummary {
7258    type Context = ();
7259
7260    fn zero(_: &Self::Context) -> Self {
7261        DiffTransformSummary {
7262            input: TextSummary::default(),
7263            output: TextSummary::default(),
7264        }
7265    }
7266
7267    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7268        self.input += &summary.input;
7269        self.output += &summary.output;
7270    }
7271}
7272
7273impl sum_tree::Summary for ExcerptId {
7274    type Context = ();
7275
7276    fn zero(_cx: &()) -> Self {
7277        Default::default()
7278    }
7279
7280    fn add_summary(&mut self, other: &Self, _: &()) {
7281        *self = *other;
7282    }
7283}
7284
7285impl sum_tree::Summary for ExcerptSummary {
7286    type Context = ();
7287
7288    fn zero(_cx: &()) -> Self {
7289        Default::default()
7290    }
7291
7292    fn add_summary(&mut self, summary: &Self, _: &()) {
7293        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7294        self.excerpt_locator = summary.excerpt_locator.clone();
7295        Summary::add_summary(&mut self.text, &summary.text, &());
7296        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7297    }
7298}
7299
7300impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7301    fn zero(_cx: &()) -> Self {
7302        Default::default()
7303    }
7304
7305    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7306        self.value += summary.text.len;
7307    }
7308}
7309
7310impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7311    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7312        Ord::cmp(&self.value, &cursor_location.text.len)
7313    }
7314}
7315
7316impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7317    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7318        Ord::cmp(&Some(self), cursor_location)
7319    }
7320}
7321
7322impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7323    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7324        Ord::cmp(self, &cursor_location.excerpt_locator)
7325    }
7326}
7327
7328impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7329    fn zero(_cx: &()) -> Self {
7330        Default::default()
7331    }
7332
7333    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7334        self.value += summary.text.lines;
7335    }
7336}
7337
7338impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7339    for ExcerptDimension<D>
7340{
7341    fn zero(_: &()) -> Self {
7342        ExcerptDimension(D::default())
7343    }
7344
7345    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7346        self.0.add_assign(&D::from_text_summary(&summary.text))
7347    }
7348}
7349
7350impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7351    fn zero(_cx: &()) -> Self {
7352        Default::default()
7353    }
7354
7355    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7356        *self = Some(&summary.excerpt_locator);
7357    }
7358}
7359
7360impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7361    fn zero(_cx: &()) -> Self {
7362        Default::default()
7363    }
7364
7365    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7366        *self = Some(summary.excerpt_id);
7367    }
7368}
7369
7370#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7371struct ExcerptDimension<T>(T);
7372
7373#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7374struct OutputDimension<T>(T);
7375
7376impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7377    fn zero(_: &()) -> Self {
7378        ExcerptOffset::new(0)
7379    }
7380
7381    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7382        self.value += summary.input.len;
7383    }
7384}
7385
7386impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7387    fn zero(_: &()) -> Self {
7388        ExcerptPoint::new(0, 0)
7389    }
7390
7391    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7392        self.value += summary.input.lines;
7393    }
7394}
7395
7396impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7397    for ExcerptDimension<D>
7398{
7399    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7400        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7401    }
7402}
7403
7404impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7405    for ExcerptDimension<D>
7406{
7407    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7408        Ord::cmp(&self.0, &cursor_location.excerpt_dimension.0)
7409    }
7410}
7411
7412impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7413    fn zero(_: &()) -> Self {
7414        ExcerptDimension(D::default())
7415    }
7416
7417    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7418        self.0.add_assign(&D::from_text_summary(&summary.input))
7419    }
7420}
7421
7422impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransforms<D>>
7423    for OutputDimension<D>
7424{
7425    fn cmp(&self, cursor_location: &DiffTransforms<D>, _: &()) -> cmp::Ordering {
7426        Ord::cmp(&self.0, &cursor_location.output_dimension.0)
7427    }
7428}
7429
7430impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7431    fn zero(_: &()) -> Self {
7432        OutputDimension(D::default())
7433    }
7434
7435    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7436        self.0.add_assign(&D::from_text_summary(&summary.output))
7437    }
7438}
7439
7440impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7441    fn zero(_: &()) -> Self {
7442        TextSummary::default()
7443    }
7444
7445    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7446        *self += summary.output
7447    }
7448}
7449
7450impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7451    fn zero(_: &()) -> Self {
7452        0
7453    }
7454
7455    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7456        *self += summary.output.len
7457    }
7458}
7459
7460impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7461    fn zero(_: &()) -> Self {
7462        Point::new(0, 0)
7463    }
7464
7465    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7466        *self += summary.output.lines
7467    }
7468}
7469
7470impl MultiBufferRows<'_> {
7471    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7472        self.point = Point::new(row, 0);
7473        self.cursor.seek(&self.point);
7474    }
7475}
7476
7477impl Iterator for MultiBufferRows<'_> {
7478    type Item = RowInfo;
7479
7480    fn next(&mut self) -> Option<Self::Item> {
7481        if self.is_empty && self.point.row == 0 {
7482            self.point += Point::new(1, 0);
7483            return Some(RowInfo {
7484                buffer_id: None,
7485                buffer_row: Some(0),
7486                multibuffer_row: Some(MultiBufferRow(0)),
7487                diff_status: None,
7488                expand_info: None,
7489            });
7490        }
7491
7492        let mut region = self.cursor.region()?;
7493        while self.point >= region.range.end {
7494            self.cursor.next();
7495            if let Some(next_region) = self.cursor.region() {
7496                region = next_region;
7497            } else if self.point == self.cursor.diff_transforms.end().output_dimension.0 {
7498                let multibuffer_row = MultiBufferRow(self.point.row);
7499                let last_excerpt = self
7500                    .cursor
7501                    .excerpts
7502                    .item()
7503                    .or(self.cursor.excerpts.prev_item())?;
7504                let last_row = last_excerpt
7505                    .range
7506                    .context
7507                    .end
7508                    .to_point(&last_excerpt.buffer)
7509                    .row;
7510
7511                let first_row = last_excerpt
7512                    .range
7513                    .context
7514                    .start
7515                    .to_point(&last_excerpt.buffer)
7516                    .row;
7517
7518                let expand_info = if self.is_singleton {
7519                    None
7520                } else {
7521                    let needs_expand_up = first_row == last_row
7522                        && last_row > 0
7523                        && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7524                    let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7525
7526                    if needs_expand_up && needs_expand_down {
7527                        Some(ExpandExcerptDirection::UpAndDown)
7528                    } else if needs_expand_up {
7529                        Some(ExpandExcerptDirection::Up)
7530                    } else if needs_expand_down {
7531                        Some(ExpandExcerptDirection::Down)
7532                    } else {
7533                        None
7534                    }
7535                    .map(|direction| ExpandInfo {
7536                        direction,
7537                        excerpt_id: last_excerpt.id,
7538                    })
7539                };
7540                self.point += Point::new(1, 0);
7541                return Some(RowInfo {
7542                    buffer_id: Some(last_excerpt.buffer_id),
7543                    buffer_row: Some(last_row),
7544                    multibuffer_row: Some(multibuffer_row),
7545                    diff_status: None,
7546                    expand_info,
7547                });
7548            } else {
7549                return None;
7550            };
7551        }
7552
7553        let overshoot = self.point - region.range.start;
7554        let buffer_point = region.buffer_range.start + overshoot;
7555        let expand_info = if self.is_singleton {
7556            None
7557        } else {
7558            let needs_expand_up = self.point.row == region.range.start.row
7559                && self.cursor.is_at_start_of_excerpt()
7560                && buffer_point.row > 0;
7561            let needs_expand_down = (region.excerpt.has_trailing_newline
7562                && self.point.row + 1 == region.range.end.row
7563                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7564                && self.cursor.is_at_end_of_excerpt()
7565                && buffer_point.row < region.buffer.max_point().row;
7566
7567            if needs_expand_up && needs_expand_down {
7568                Some(ExpandExcerptDirection::UpAndDown)
7569            } else if needs_expand_up {
7570                Some(ExpandExcerptDirection::Up)
7571            } else if needs_expand_down {
7572                Some(ExpandExcerptDirection::Down)
7573            } else {
7574                None
7575            }
7576            .map(|direction| ExpandInfo {
7577                direction,
7578                excerpt_id: region.excerpt.id,
7579            })
7580        };
7581
7582        let result = Some(RowInfo {
7583            buffer_id: Some(region.buffer.remote_id()),
7584            buffer_row: Some(buffer_point.row),
7585            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7586            diff_status: region
7587                .diff_hunk_status
7588                .filter(|_| self.point < region.range.end),
7589            expand_info,
7590        });
7591        self.point += Point::new(1, 0);
7592        result
7593    }
7594}
7595
7596impl<'a> MultiBufferChunks<'a> {
7597    pub fn offset(&self) -> usize {
7598        self.range.start
7599    }
7600
7601    pub fn seek(&mut self, range: Range<usize>) {
7602        self.diff_transforms.seek(&range.end, Bias::Right);
7603        let mut excerpt_end = self.diff_transforms.start().1;
7604        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7605            let overshoot = range.end - self.diff_transforms.start().0;
7606            excerpt_end.value += overshoot;
7607        }
7608
7609        self.diff_transforms.seek(&range.start, Bias::Right);
7610        let mut excerpt_start = self.diff_transforms.start().1;
7611        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7612            let overshoot = range.start - self.diff_transforms.start().0;
7613            excerpt_start.value += overshoot;
7614        }
7615
7616        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7617        self.buffer_chunk.take();
7618        self.range = range;
7619    }
7620
7621    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7622        self.excerpt_offset_range = new_range.clone();
7623        self.excerpts.seek(&new_range.start, Bias::Right);
7624        if let Some(excerpt) = self.excerpts.item() {
7625            let excerpt_start = *self.excerpts.start();
7626            if let Some(excerpt_chunks) = self
7627                .excerpt_chunks
7628                .as_mut()
7629                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7630            {
7631                excerpt.seek_chunks(
7632                    excerpt_chunks,
7633                    (self.excerpt_offset_range.start - excerpt_start).value
7634                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7635                );
7636            } else {
7637                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7638                    (self.excerpt_offset_range.start - excerpt_start).value
7639                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7640                    self.language_aware,
7641                ));
7642            }
7643        } else {
7644            self.excerpt_chunks = None;
7645        }
7646    }
7647
7648    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7649        loop {
7650            if self.excerpt_offset_range.is_empty() {
7651                return None;
7652            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7653                self.excerpt_offset_range.start.value += chunk.text.len();
7654                return Some(chunk);
7655            } else {
7656                self.excerpts.next();
7657                let excerpt = self.excerpts.item()?;
7658                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7659                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7660                    self.language_aware,
7661                ));
7662            }
7663        }
7664    }
7665}
7666
7667impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7668    type Item = &'a str;
7669
7670    fn next(&mut self) -> Option<Self::Item> {
7671        let mut region = self.cursor.region()?;
7672        if self.offset == region.range.start {
7673            self.cursor.prev();
7674            region = self.cursor.region()?;
7675            let start_overshoot = self.start.saturating_sub(region.range.start);
7676            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7677                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7678            ));
7679        }
7680
7681        if self.offset == region.range.end && region.has_trailing_newline {
7682            self.offset -= 1;
7683            Some("\n")
7684        } else {
7685            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7686            self.offset -= chunk.len();
7687            Some(chunk)
7688        }
7689    }
7690}
7691
7692impl<'a> Iterator for MultiBufferChunks<'a> {
7693    type Item = Chunk<'a>;
7694
7695    fn next(&mut self) -> Option<Chunk<'a>> {
7696        if self.range.start >= self.range.end {
7697            return None;
7698        }
7699        if self.range.start == self.diff_transforms.end().0 {
7700            self.diff_transforms.next();
7701        }
7702
7703        let diff_transform_start = self.diff_transforms.start().0;
7704        let diff_transform_end = self.diff_transforms.end().0;
7705        debug_assert!(self.range.start < diff_transform_end);
7706
7707        let diff_transform = self.diff_transforms.item()?;
7708        match diff_transform {
7709            DiffTransform::BufferContent { .. } => {
7710                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7711                    chunk
7712                } else {
7713                    let chunk = self.next_excerpt_chunk().unwrap();
7714                    self.buffer_chunk.insert(chunk)
7715                };
7716
7717                let chunk_end = self.range.start + chunk.text.len();
7718                let diff_transform_end = diff_transform_end.min(self.range.end);
7719
7720                if diff_transform_end < chunk_end {
7721                    let (before, after) =
7722                        chunk.text.split_at(diff_transform_end - self.range.start);
7723                    self.range.start = diff_transform_end;
7724                    chunk.text = after;
7725                    Some(Chunk {
7726                        text: before,
7727                        ..chunk.clone()
7728                    })
7729                } else {
7730                    self.range.start = chunk_end;
7731                    self.buffer_chunk.take()
7732                }
7733            }
7734            DiffTransform::DeletedHunk {
7735                buffer_id,
7736                base_text_byte_range,
7737                has_trailing_newline,
7738                ..
7739            } => {
7740                let base_text_start =
7741                    base_text_byte_range.start + self.range.start - diff_transform_start;
7742                let base_text_end =
7743                    base_text_byte_range.start + self.range.end - diff_transform_start;
7744                let base_text_end = base_text_end.min(base_text_byte_range.end);
7745
7746                let mut chunks = if let Some((_, mut chunks)) = self
7747                    .diff_base_chunks
7748                    .take()
7749                    .filter(|(id, _)| id == buffer_id)
7750                {
7751                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7752                    {
7753                        chunks.seek(base_text_start..base_text_end);
7754                    }
7755                    chunks
7756                } else {
7757                    let base_buffer = &self.diffs.get(buffer_id)?.base_text();
7758                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7759                };
7760
7761                let chunk = if let Some(chunk) = chunks.next() {
7762                    self.range.start += chunk.text.len();
7763                    self.diff_base_chunks = Some((*buffer_id, chunks));
7764                    chunk
7765                } else {
7766                    debug_assert!(has_trailing_newline);
7767                    self.range.start += "\n".len();
7768                    Chunk {
7769                        text: "\n",
7770                        ..Default::default()
7771                    }
7772                };
7773                Some(chunk)
7774            }
7775        }
7776    }
7777}
7778
7779impl MultiBufferBytes<'_> {
7780    fn consume(&mut self, len: usize) {
7781        self.range.start += len;
7782        self.chunk = &self.chunk[len..];
7783
7784        if !self.range.is_empty() && self.chunk.is_empty() {
7785            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7786                self.chunk = chunk;
7787            } else if self.has_trailing_newline {
7788                self.has_trailing_newline = false;
7789                self.chunk = b"\n";
7790            } else {
7791                self.cursor.next();
7792                if let Some(region) = self.cursor.region() {
7793                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7794                        region.buffer_range.start
7795                            ..(region.buffer_range.start + self.range.end - region.range.start)
7796                                .min(region.buffer_range.end),
7797                    );
7798                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7799                    self.excerpt_bytes = Some(excerpt_bytes);
7800                    self.has_trailing_newline =
7801                        region.has_trailing_newline && self.range.end >= region.range.end;
7802                    if self.chunk.is_empty() && self.has_trailing_newline {
7803                        self.has_trailing_newline = false;
7804                        self.chunk = b"\n";
7805                    }
7806                }
7807            }
7808        }
7809    }
7810}
7811
7812impl<'a> Iterator for MultiBufferBytes<'a> {
7813    type Item = &'a [u8];
7814
7815    fn next(&mut self) -> Option<Self::Item> {
7816        let chunk = self.chunk;
7817        if chunk.is_empty() {
7818            None
7819        } else {
7820            self.consume(chunk.len());
7821            Some(chunk)
7822        }
7823    }
7824}
7825
7826impl io::Read for MultiBufferBytes<'_> {
7827    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7828        let len = cmp::min(buf.len(), self.chunk.len());
7829        buf[..len].copy_from_slice(&self.chunk[..len]);
7830        if len > 0 {
7831            self.consume(len);
7832        }
7833        Ok(len)
7834    }
7835}
7836
7837impl io::Read for ReversedMultiBufferBytes<'_> {
7838    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7839        let len = cmp::min(buf.len(), self.chunk.len());
7840        buf[..len].copy_from_slice(&self.chunk[..len]);
7841        buf[..len].reverse();
7842        if len > 0 {
7843            self.range.end -= len;
7844            self.chunk = &self.chunk[..self.chunk.len() - len];
7845            if !self.range.is_empty()
7846                && self.chunk.is_empty()
7847                && let Some(chunk) = self.chunks.next()
7848            {
7849                self.chunk = chunk.as_bytes();
7850            }
7851        }
7852        Ok(len)
7853    }
7854}
7855
7856impl<'a> Iterator for ExcerptChunks<'a> {
7857    type Item = Chunk<'a>;
7858
7859    fn next(&mut self) -> Option<Self::Item> {
7860        if let Some(chunk) = self.content_chunks.next() {
7861            return Some(chunk);
7862        }
7863
7864        if self.footer_height > 0 {
7865            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7866            self.footer_height = 0;
7867            return Some(Chunk {
7868                text,
7869                ..Default::default()
7870            });
7871        }
7872
7873        None
7874    }
7875}
7876
7877impl ToOffset for Point {
7878    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7879        snapshot.point_to_offset(*self)
7880    }
7881}
7882
7883impl ToOffset for usize {
7884    #[track_caller]
7885    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7886        assert!(
7887            *self <= snapshot.len(),
7888            "offset {} is greater than the snapshot.len() {}",
7889            *self,
7890            snapshot.len(),
7891        );
7892        *self
7893    }
7894}
7895
7896impl ToOffset for OffsetUtf16 {
7897    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7898        snapshot.offset_utf16_to_offset(*self)
7899    }
7900}
7901
7902impl ToOffset for PointUtf16 {
7903    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7904        snapshot.point_utf16_to_offset(*self)
7905    }
7906}
7907
7908impl ToOffsetUtf16 for OffsetUtf16 {
7909    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7910        *self
7911    }
7912}
7913
7914impl ToOffsetUtf16 for usize {
7915    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7916        snapshot.offset_to_offset_utf16(*self)
7917    }
7918}
7919
7920impl ToPoint for usize {
7921    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7922        snapshot.offset_to_point(*self)
7923    }
7924}
7925
7926impl ToPoint for Point {
7927    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7928        *self
7929    }
7930}
7931
7932impl ToPointUtf16 for usize {
7933    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7934        snapshot.offset_to_point_utf16(*self)
7935    }
7936}
7937
7938impl ToPointUtf16 for Point {
7939    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7940        snapshot.point_to_point_utf16(*self)
7941    }
7942}
7943
7944impl ToPointUtf16 for PointUtf16 {
7945    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7946        *self
7947    }
7948}
7949
7950impl From<ExcerptId> for EntityId {
7951    fn from(id: ExcerptId) -> Self {
7952        EntityId::from(id.0 as u64)
7953    }
7954}