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