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        self.excerpts_by_path.clear();
2045        self.paths_by_excerpt.clear();
2046        let mut snapshot = self.snapshot.borrow_mut();
2047        let start = ExcerptOffset::new(0);
2048        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
2049        snapshot.excerpts = Default::default();
2050        snapshot.trailing_excerpt_update_count += 1;
2051        snapshot.is_dirty = false;
2052        snapshot.has_deleted_file = false;
2053        snapshot.has_conflict = false;
2054        snapshot.replaced_excerpts.clear();
2055
2056        self.sync_diff_transforms(
2057            &mut snapshot,
2058            vec![Edit {
2059                old: start..prev_len,
2060                new: start..start,
2061            }],
2062            DiffChangeKind::BufferEdited,
2063        );
2064        cx.emit(Event::Edited {
2065            singleton_buffer_edited: false,
2066            edited_buffer: None,
2067        });
2068        cx.emit(Event::ExcerptsRemoved { ids });
2069        cx.notify();
2070    }
2071
2072    pub fn excerpts_for_buffer(
2073        &self,
2074        buffer_id: BufferId,
2075        cx: &App,
2076    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2077        let mut excerpts = Vec::new();
2078        let snapshot = self.read(cx);
2079        let buffers = self.buffers.borrow();
2080        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2081        for locator in buffers
2082            .get(&buffer_id)
2083            .map(|state| &state.excerpts)
2084            .into_iter()
2085            .flatten()
2086        {
2087            cursor.seek_forward(&Some(locator), Bias::Left, &());
2088            if let Some(excerpt) = cursor.item() {
2089                if excerpt.locator == *locator {
2090                    excerpts.push((excerpt.id, excerpt.range.clone()));
2091                }
2092            }
2093        }
2094
2095        excerpts
2096    }
2097
2098    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2099        let snapshot = self.read(cx);
2100        let buffers = self.buffers.borrow();
2101        let mut excerpts = snapshot
2102            .excerpts
2103            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
2104        let mut diff_transforms = snapshot
2105            .diff_transforms
2106            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
2107        diff_transforms.next(&());
2108        let locators = buffers
2109            .get(&buffer_id)
2110            .into_iter()
2111            .flat_map(|state| &state.excerpts);
2112        let mut result = Vec::new();
2113        for locator in locators {
2114            excerpts.seek_forward(&Some(locator), Bias::Left, &());
2115            if let Some(excerpt) = excerpts.item() {
2116                if excerpt.locator == *locator {
2117                    let excerpt_start = excerpts.start().1.clone();
2118                    let excerpt_end =
2119                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2120
2121                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
2122                    let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
2123                    let start = diff_transforms.start().1.0 + overshoot;
2124
2125                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
2126                    let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
2127                    let end = diff_transforms.start().1.0 + overshoot;
2128
2129                    result.push(start..end)
2130                }
2131            }
2132        }
2133        result
2134    }
2135
2136    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2137        self.snapshot
2138            .borrow()
2139            .excerpts
2140            .iter()
2141            .map(|entry| entry.buffer_id)
2142            .collect()
2143    }
2144
2145    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2146        self.snapshot
2147            .borrow()
2148            .excerpts
2149            .iter()
2150            .map(|entry| entry.id)
2151            .collect()
2152    }
2153
2154    pub fn excerpt_containing(
2155        &self,
2156        position: impl ToOffset,
2157        cx: &App,
2158    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2159        let snapshot = self.read(cx);
2160        let offset = position.to_offset(&snapshot);
2161
2162        let mut cursor = snapshot.cursor::<usize>();
2163        cursor.seek(&offset);
2164        cursor
2165            .excerpt()
2166            .or_else(|| snapshot.excerpts.last())
2167            .map(|excerpt| {
2168                (
2169                    excerpt.id,
2170                    self.buffers
2171                        .borrow()
2172                        .get(&excerpt.buffer_id)
2173                        .unwrap()
2174                        .buffer
2175                        .clone(),
2176                    excerpt.range.context.clone(),
2177                )
2178            })
2179    }
2180
2181    // If point is at the end of the buffer, the last excerpt is returned
2182    pub fn point_to_buffer_offset<T: ToOffset>(
2183        &self,
2184        point: T,
2185        cx: &App,
2186    ) -> Option<(Entity<Buffer>, usize)> {
2187        let snapshot = self.read(cx);
2188        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2189        Some((
2190            self.buffers
2191                .borrow()
2192                .get(&buffer.remote_id())?
2193                .buffer
2194                .clone(),
2195            offset,
2196        ))
2197    }
2198
2199    // If point is at the end of the buffer, the last excerpt is returned
2200    pub fn point_to_buffer_point<T: ToPoint>(
2201        &self,
2202        point: T,
2203        cx: &App,
2204    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2205        let snapshot = self.read(cx);
2206        let (buffer, point, is_main_buffer) =
2207            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2208        Some((
2209            self.buffers
2210                .borrow()
2211                .get(&buffer.remote_id())?
2212                .buffer
2213                .clone(),
2214            point,
2215            is_main_buffer,
2216        ))
2217    }
2218
2219    pub fn buffer_point_to_anchor(
2220        &self,
2221        buffer: &Entity<Buffer>,
2222        point: Point,
2223        cx: &App,
2224    ) -> Option<Anchor> {
2225        let mut found = None;
2226        let snapshot = buffer.read(cx).snapshot();
2227        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2228            let start = range.context.start.to_point(&snapshot);
2229            let end = range.context.end.to_point(&snapshot);
2230            if start <= point && point < end {
2231                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2232                break;
2233            }
2234            if point < start {
2235                found = Some((start, excerpt_id));
2236            }
2237            if point > end {
2238                found = Some((end, excerpt_id));
2239            }
2240        }
2241
2242        found.map(|(point, excerpt_id)| {
2243            let text_anchor = snapshot.anchor_after(point);
2244            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2245        })
2246    }
2247
2248    pub fn remove_excerpts(
2249        &mut self,
2250        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2251        cx: &mut Context<Self>,
2252    ) {
2253        self.sync(cx);
2254        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2255        if ids.is_empty() {
2256            return;
2257        }
2258
2259        let mut buffers = self.buffers.borrow_mut();
2260        let mut snapshot = self.snapshot.borrow_mut();
2261        let mut new_excerpts = SumTree::default();
2262        let mut cursor = snapshot
2263            .excerpts
2264            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2265        let mut edits = Vec::new();
2266        let mut excerpt_ids = ids.iter().copied().peekable();
2267        let mut removed_buffer_ids = Vec::new();
2268
2269        while let Some(excerpt_id) = excerpt_ids.next() {
2270            self.paths_by_excerpt.remove(&excerpt_id);
2271            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2272            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2273            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2274
2275            if let Some(mut excerpt) = cursor.item() {
2276                if excerpt.id != excerpt_id {
2277                    continue;
2278                }
2279                let mut old_start = cursor.start().1;
2280
2281                // Skip over the removed excerpt.
2282                'remove_excerpts: loop {
2283                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2284                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2285                        if buffer_state.excerpts.is_empty() {
2286                            log::debug!(
2287                                "removing buffer and diff for buffer {}",
2288                                excerpt.buffer_id
2289                            );
2290                            buffers.remove(&excerpt.buffer_id);
2291                            removed_buffer_ids.push(excerpt.buffer_id);
2292                        }
2293                    }
2294                    cursor.next(&());
2295
2296                    // Skip over any subsequent excerpts that are also removed.
2297                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2298                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2299                        if let Some(next_excerpt) = cursor.item() {
2300                            if next_excerpt.locator == *next_locator {
2301                                excerpt_ids.next();
2302                                excerpt = next_excerpt;
2303                                continue 'remove_excerpts;
2304                            }
2305                        }
2306                    }
2307
2308                    break;
2309                }
2310
2311                // When removing the last excerpt, remove the trailing newline from
2312                // the previous excerpt.
2313                if cursor.item().is_none() && old_start.value > 0 {
2314                    old_start.value -= 1;
2315                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2316                }
2317
2318                // Push an edit for the removal of this run of excerpts.
2319                let old_end = cursor.start().1;
2320                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2321                edits.push(Edit {
2322                    old: old_start..old_end,
2323                    new: new_start..new_start,
2324                });
2325            }
2326        }
2327        let suffix = cursor.suffix(&());
2328        let changed_trailing_excerpt = suffix.is_empty();
2329        new_excerpts.append(suffix, &());
2330        drop(cursor);
2331        snapshot.excerpts = new_excerpts;
2332        for buffer_id in removed_buffer_ids {
2333            self.diffs.remove(&buffer_id);
2334            snapshot.diffs.remove(&buffer_id);
2335        }
2336
2337        if changed_trailing_excerpt {
2338            snapshot.trailing_excerpt_update_count += 1;
2339        }
2340
2341        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2342        self.buffer_changed_since_sync.replace(true);
2343        cx.emit(Event::Edited {
2344            singleton_buffer_edited: false,
2345            edited_buffer: None,
2346        });
2347        cx.emit(Event::ExcerptsRemoved { ids });
2348        cx.notify();
2349    }
2350
2351    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2352        &self,
2353        anchors: Anchors,
2354        cx: &mut Context<Self>,
2355    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2356        let borrow = self.buffers.borrow();
2357        let mut error = None;
2358        let mut futures = Vec::new();
2359        for anchor in anchors {
2360            if let Some(buffer_id) = anchor.buffer_id {
2361                if let Some(buffer) = borrow.get(&buffer_id) {
2362                    buffer.buffer.update(cx, |buffer, _| {
2363                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2364                    });
2365                } else {
2366                    error = Some(anyhow!(
2367                        "buffer {buffer_id} is not part of this multi-buffer"
2368                    ));
2369                    break;
2370                }
2371            }
2372        }
2373        async move {
2374            if let Some(error) = error {
2375                Err(error)?;
2376            }
2377            for future in futures {
2378                future.await?;
2379            }
2380            Ok(())
2381        }
2382    }
2383
2384    pub fn text_anchor_for_position<T: ToOffset>(
2385        &self,
2386        position: T,
2387        cx: &App,
2388    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2389        let snapshot = self.read(cx);
2390        let anchor = snapshot.anchor_before(position);
2391        let buffer = self
2392            .buffers
2393            .borrow()
2394            .get(&anchor.buffer_id?)?
2395            .buffer
2396            .clone();
2397        Some((buffer, anchor.text_anchor))
2398    }
2399
2400    fn on_buffer_event(
2401        &mut self,
2402        buffer: Entity<Buffer>,
2403        event: &language::BufferEvent,
2404        cx: &mut Context<Self>,
2405    ) {
2406        cx.emit(match event {
2407            language::BufferEvent::Edited => Event::Edited {
2408                singleton_buffer_edited: true,
2409                edited_buffer: Some(buffer.clone()),
2410            },
2411            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2412            language::BufferEvent::Saved => Event::Saved,
2413            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2414            language::BufferEvent::Reloaded => Event::Reloaded,
2415            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2416            language::BufferEvent::LanguageChanged => {
2417                Event::LanguageChanged(buffer.read(cx).remote_id())
2418            }
2419            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2420            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2421            language::BufferEvent::Closed => Event::Closed,
2422            language::BufferEvent::Discarded => Event::Discarded,
2423            language::BufferEvent::CapabilityChanged => {
2424                self.capability = buffer.read(cx).capability();
2425                Event::CapabilityChanged
2426            }
2427            language::BufferEvent::Operation { .. } => return,
2428        });
2429    }
2430
2431    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2432        self.sync(cx);
2433        let mut snapshot = self.snapshot.borrow_mut();
2434        let diff = diff.read(cx);
2435        let buffer_id = diff.buffer_id;
2436        let diff = diff.snapshot(cx);
2437        snapshot.diffs.insert(buffer_id, diff);
2438    }
2439
2440    fn buffer_diff_changed(
2441        &mut self,
2442        diff: Entity<BufferDiff>,
2443        range: Range<text::Anchor>,
2444        cx: &mut Context<Self>,
2445    ) {
2446        self.sync(cx);
2447        self.buffer_changed_since_sync.replace(true);
2448
2449        let diff = diff.read(cx);
2450        let buffer_id = diff.buffer_id;
2451        let buffers = self.buffers.borrow();
2452        let Some(buffer_state) = buffers.get(&buffer_id) else {
2453            eprintln!("no buffer");
2454            return;
2455        };
2456
2457        let buffer = buffer_state.buffer.read(cx);
2458        let diff_change_range = range.to_offset(buffer);
2459
2460        let new_diff = diff.snapshot(cx);
2461        let mut snapshot = self.snapshot.borrow_mut();
2462        let base_text_changed = snapshot
2463            .diffs
2464            .get(&buffer_id)
2465            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2466
2467        snapshot.diffs.insert(buffer_id, new_diff);
2468
2469        let mut excerpt_edits = Vec::new();
2470        for locator in &buffer_state.excerpts {
2471            let mut cursor = snapshot
2472                .excerpts
2473                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2474            cursor.seek_forward(&Some(locator), Bias::Left, &());
2475            if let Some(excerpt) = cursor.item() {
2476                if excerpt.locator == *locator {
2477                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2478                    if diff_change_range.end < excerpt_buffer_range.start
2479                        || diff_change_range.start > excerpt_buffer_range.end
2480                    {
2481                        continue;
2482                    }
2483                    let excerpt_start = cursor.start().1;
2484                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2485                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2486                        diff_change_range
2487                            .start
2488                            .saturating_sub(excerpt_buffer_range.start),
2489                    );
2490                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2491                        diff_change_range
2492                            .end
2493                            .saturating_sub(excerpt_buffer_range.start),
2494                    );
2495                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2496                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2497                    excerpt_edits.push(Edit {
2498                        old: edit_start..edit_end,
2499                        new: edit_start..edit_end,
2500                    });
2501                }
2502            }
2503        }
2504
2505        self.sync_diff_transforms(
2506            &mut snapshot,
2507            excerpt_edits,
2508            DiffChangeKind::DiffUpdated {
2509                base_changed: base_text_changed,
2510            },
2511        );
2512        cx.emit(Event::Edited {
2513            singleton_buffer_edited: false,
2514            edited_buffer: None,
2515        });
2516    }
2517
2518    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2519        self.buffers
2520            .borrow()
2521            .values()
2522            .map(|state| state.buffer.clone())
2523            .collect()
2524    }
2525
2526    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2527        self.buffers
2528            .borrow()
2529            .get(&buffer_id)
2530            .map(|state| state.buffer.clone())
2531    }
2532
2533    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2534        self.point_to_buffer_offset(point, cx)
2535            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2536    }
2537
2538    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2539        let buffer_id = self
2540            .snapshot
2541            .borrow()
2542            .excerpts
2543            .first()
2544            .map(|excerpt| excerpt.buffer.remote_id());
2545        buffer_id
2546            .and_then(|buffer_id| self.buffer(buffer_id))
2547            .map(|buffer| {
2548                let buffer = buffer.read(cx);
2549                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2550            })
2551            .unwrap_or_else(move || self.language_settings_at(0, cx))
2552    }
2553
2554    pub fn language_settings_at<'a, T: ToOffset>(
2555        &'a self,
2556        point: T,
2557        cx: &'a App,
2558    ) -> Cow<'a, LanguageSettings> {
2559        let mut language = None;
2560        let mut file = None;
2561        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2562            let buffer = buffer.read(cx);
2563            language = buffer.language_at(offset);
2564            file = buffer.file();
2565        }
2566        language_settings(language.map(|l| l.name()), file, cx)
2567    }
2568
2569    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2570        self.buffers
2571            .borrow()
2572            .values()
2573            .for_each(|state| f(&state.buffer))
2574    }
2575
2576    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2577        if let Some(title) = self.title.as_ref() {
2578            return title.into();
2579        }
2580
2581        if let Some(buffer) = self.as_singleton() {
2582            if let Some(file) = buffer.read(cx).file() {
2583                return file.file_name(cx).to_string_lossy();
2584            }
2585        }
2586
2587        "untitled".into()
2588    }
2589
2590    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2591        self.title = Some(title);
2592        cx.notify();
2593    }
2594
2595    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2596    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2597        for buffer_state in self.buffers.borrow().values() {
2598            buffer_state
2599                .buffer
2600                .update(cx, |buffer, _cx| buffer.refresh_preview());
2601        }
2602    }
2603
2604    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2605    pub fn preserve_preview(&self, cx: &App) -> bool {
2606        self.buffers
2607            .borrow()
2608            .values()
2609            .all(|state| state.buffer.read(cx).preserve_preview())
2610    }
2611
2612    #[cfg(any(test, feature = "test-support"))]
2613    pub fn is_parsing(&self, cx: &App) -> bool {
2614        self.as_singleton().unwrap().read(cx).is_parsing()
2615    }
2616
2617    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2618        let buffer_id = diff.read(cx).buffer_id;
2619        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2620        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2621    }
2622
2623    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2624        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2625    }
2626
2627    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2628        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2629    }
2630
2631    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2632        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2633    }
2634
2635    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2636        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2637        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2638    }
2639
2640    pub fn all_diff_hunks_expanded(&self) -> bool {
2641        self.snapshot.borrow().all_diff_hunks_expanded
2642    }
2643
2644    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2645        self.read(cx)
2646            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2647            .nth(1)
2648            .is_some()
2649    }
2650
2651    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2652        let snapshot = self.read(cx);
2653        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2654        let offset_range = range.to_offset(&snapshot);
2655        cursor.seek(&offset_range.start, Bias::Left, &());
2656        while let Some(item) = cursor.item() {
2657            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2658                break;
2659            }
2660            if item.hunk_info().is_some() {
2661                return true;
2662            }
2663            cursor.next(&());
2664        }
2665        false
2666    }
2667
2668    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2669        let snapshot = self.read(cx);
2670        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2671        for range in ranges {
2672            let range = range.to_point(&snapshot);
2673            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2674            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2675            let start = start.saturating_sub(1);
2676            let end = snapshot.len().min(end + 1);
2677            cursor.seek(&start, Bias::Right, &());
2678            while let Some(item) = cursor.item() {
2679                if *cursor.start() >= end {
2680                    break;
2681                }
2682                if item.hunk_info().is_some() {
2683                    return true;
2684                }
2685                cursor.next(&());
2686            }
2687        }
2688        false
2689    }
2690
2691    pub fn expand_or_collapse_diff_hunks_inner(
2692        &mut self,
2693        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2694        expand: bool,
2695        cx: &mut Context<Self>,
2696    ) {
2697        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2698            return;
2699        }
2700        self.sync(cx);
2701        let mut snapshot = self.snapshot.borrow_mut();
2702        let mut excerpt_edits = Vec::new();
2703        for (range, end_excerpt_id) in ranges {
2704            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2705                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2706                    continue;
2707                }
2708                let start = Anchor::in_buffer(
2709                    diff_hunk.excerpt_id,
2710                    diff_hunk.buffer_id,
2711                    diff_hunk.buffer_range.start,
2712                );
2713                let end = Anchor::in_buffer(
2714                    diff_hunk.excerpt_id,
2715                    diff_hunk.buffer_id,
2716                    diff_hunk.buffer_range.end,
2717                );
2718                let start = snapshot.excerpt_offset_for_anchor(&start);
2719                let end = snapshot.excerpt_offset_for_anchor(&end);
2720                excerpt_edits.push(text::Edit {
2721                    old: start..end,
2722                    new: start..end,
2723                });
2724            }
2725        }
2726
2727        self.sync_diff_transforms(
2728            &mut snapshot,
2729            excerpt_edits,
2730            DiffChangeKind::ExpandOrCollapseHunks { expand },
2731        );
2732        cx.emit(Event::DiffHunksToggled);
2733        cx.emit(Event::Edited {
2734            singleton_buffer_edited: false,
2735            edited_buffer: None,
2736        });
2737    }
2738
2739    pub fn expand_or_collapse_diff_hunks(
2740        &mut self,
2741        ranges: Vec<Range<Anchor>>,
2742        expand: bool,
2743        cx: &mut Context<Self>,
2744    ) {
2745        let snapshot = self.snapshot.borrow().clone();
2746        let ranges = ranges.iter().map(move |range| {
2747            let end_excerpt_id = range.end.excerpt_id;
2748            let range = range.to_point(&snapshot);
2749            let mut peek_end = range.end;
2750            if range.end.row < snapshot.max_row().0 {
2751                peek_end = Point::new(range.end.row + 1, 0);
2752            };
2753            (range.start..peek_end, end_excerpt_id)
2754        });
2755        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2756    }
2757
2758    pub fn resize_excerpt(
2759        &mut self,
2760        id: ExcerptId,
2761        range: Range<text::Anchor>,
2762        cx: &mut Context<Self>,
2763    ) {
2764        self.sync(cx);
2765
2766        let mut snapshot = self.snapshot.borrow_mut();
2767        let locator = snapshot.excerpt_locator_for_id(id);
2768        let mut new_excerpts = SumTree::default();
2769        let mut cursor = snapshot
2770            .excerpts
2771            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2772        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2773
2774        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2775        new_excerpts.append(prefix, &());
2776
2777        let mut excerpt = cursor.item().unwrap().clone();
2778        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2779
2780        excerpt.range.context.start = range.start;
2781        excerpt.range.context.end = range.end;
2782        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2783
2784        excerpt.text_summary = excerpt
2785            .buffer
2786            .text_summary_for_range(excerpt.range.context.clone());
2787
2788        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2789        let old_start_offset = cursor.start().1;
2790        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2791        let edit = Edit {
2792            old: old_start_offset..old_start_offset + old_text_len,
2793            new: new_start_offset..new_start_offset + new_text_len,
2794        };
2795
2796        if let Some(last_edit) = edits.last_mut() {
2797            if last_edit.old.end == edit.old.start {
2798                last_edit.old.end = edit.old.end;
2799                last_edit.new.end = edit.new.end;
2800            } else {
2801                edits.push(edit);
2802            }
2803        } else {
2804            edits.push(edit);
2805        }
2806
2807        new_excerpts.push(excerpt, &());
2808
2809        cursor.next(&());
2810
2811        new_excerpts.append(cursor.suffix(&()), &());
2812
2813        drop(cursor);
2814        snapshot.excerpts = new_excerpts;
2815
2816        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2817        cx.emit(Event::Edited {
2818            singleton_buffer_edited: false,
2819            edited_buffer: None,
2820        });
2821        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2822        cx.notify();
2823    }
2824
2825    pub fn expand_excerpts(
2826        &mut self,
2827        ids: impl IntoIterator<Item = ExcerptId>,
2828        line_count: u32,
2829        direction: ExpandExcerptDirection,
2830        cx: &mut Context<Self>,
2831    ) {
2832        if line_count == 0 {
2833            return;
2834        }
2835        self.sync(cx);
2836        if !self.excerpts_by_path.is_empty() {
2837            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2838            return;
2839        }
2840        let mut snapshot = self.snapshot.borrow_mut();
2841
2842        let ids = ids.into_iter().collect::<Vec<_>>();
2843        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2844        let mut new_excerpts = SumTree::default();
2845        let mut cursor = snapshot
2846            .excerpts
2847            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2848        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2849
2850        for locator in &locators {
2851            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2852            new_excerpts.append(prefix, &());
2853
2854            let mut excerpt = cursor.item().unwrap().clone();
2855            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2856
2857            let up_line_count = if direction.should_expand_up() {
2858                line_count
2859            } else {
2860                0
2861            };
2862
2863            let start_row = excerpt
2864                .range
2865                .context
2866                .start
2867                .to_point(&excerpt.buffer)
2868                .row
2869                .saturating_sub(up_line_count);
2870            let start_point = Point::new(start_row, 0);
2871            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2872
2873            let down_line_count = if direction.should_expand_down() {
2874                line_count
2875            } else {
2876                0
2877            };
2878
2879            let mut end_point = excerpt.buffer.clip_point(
2880                excerpt.range.context.end.to_point(&excerpt.buffer)
2881                    + Point::new(down_line_count, 0),
2882                Bias::Left,
2883            );
2884            end_point.column = excerpt.buffer.line_len(end_point.row);
2885            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2886            excerpt.max_buffer_row = end_point.row;
2887
2888            excerpt.text_summary = excerpt
2889                .buffer
2890                .text_summary_for_range(excerpt.range.context.clone());
2891
2892            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2893            let old_start_offset = cursor.start().1;
2894            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2895            let edit = Edit {
2896                old: old_start_offset..old_start_offset + old_text_len,
2897                new: new_start_offset..new_start_offset + new_text_len,
2898            };
2899
2900            if let Some(last_edit) = edits.last_mut() {
2901                if last_edit.old.end == edit.old.start {
2902                    last_edit.old.end = edit.old.end;
2903                    last_edit.new.end = edit.new.end;
2904                } else {
2905                    edits.push(edit);
2906                }
2907            } else {
2908                edits.push(edit);
2909            }
2910
2911            new_excerpts.push(excerpt, &());
2912
2913            cursor.next(&());
2914        }
2915
2916        new_excerpts.append(cursor.suffix(&()), &());
2917
2918        drop(cursor);
2919        snapshot.excerpts = new_excerpts;
2920
2921        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2922        cx.emit(Event::Edited {
2923            singleton_buffer_edited: false,
2924            edited_buffer: None,
2925        });
2926        cx.emit(Event::ExcerptsExpanded { ids });
2927        cx.notify();
2928    }
2929
2930    fn sync(&self, cx: &App) {
2931        let changed = self.buffer_changed_since_sync.replace(false);
2932        if !changed {
2933            return;
2934        }
2935
2936        let mut snapshot = self.snapshot.borrow_mut();
2937        let mut excerpts_to_edit = Vec::new();
2938        let mut non_text_state_updated = false;
2939        let mut is_dirty = false;
2940        let mut has_deleted_file = false;
2941        let mut has_conflict = false;
2942        let mut edited = false;
2943        let mut buffers = self.buffers.borrow_mut();
2944        for buffer_state in buffers.values_mut() {
2945            let buffer = buffer_state.buffer.read(cx);
2946            let version = buffer.version();
2947            let non_text_state_update_count = buffer.non_text_state_update_count();
2948
2949            let buffer_edited = version.changed_since(&buffer_state.last_version);
2950            let buffer_non_text_state_updated =
2951                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2952            if buffer_edited || buffer_non_text_state_updated {
2953                buffer_state.last_version = version;
2954                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2955                excerpts_to_edit.extend(
2956                    buffer_state
2957                        .excerpts
2958                        .iter()
2959                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2960                );
2961            }
2962
2963            edited |= buffer_edited;
2964            non_text_state_updated |= buffer_non_text_state_updated;
2965            is_dirty |= buffer.is_dirty();
2966            has_deleted_file |= buffer
2967                .file()
2968                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2969            has_conflict |= buffer.has_conflict();
2970        }
2971        if edited {
2972            snapshot.edit_count += 1;
2973        }
2974        if non_text_state_updated {
2975            snapshot.non_text_state_update_count += 1;
2976        }
2977        snapshot.is_dirty = is_dirty;
2978        snapshot.has_deleted_file = has_deleted_file;
2979        snapshot.has_conflict = has_conflict;
2980
2981        for (id, diff) in self.diffs.iter() {
2982            if snapshot.diffs.get(&id).is_none() {
2983                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
2984            }
2985        }
2986
2987        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
2988
2989        let mut edits = Vec::new();
2990        let mut new_excerpts = SumTree::default();
2991        let mut cursor = snapshot
2992            .excerpts
2993            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2994
2995        for (locator, buffer, buffer_edited) in excerpts_to_edit {
2996            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2997            let old_excerpt = cursor.item().unwrap();
2998            let buffer = buffer.read(cx);
2999            let buffer_id = buffer.remote_id();
3000
3001            let mut new_excerpt;
3002            if buffer_edited {
3003                edits.extend(
3004                    buffer
3005                        .edits_since_in_range::<usize>(
3006                            old_excerpt.buffer.version(),
3007                            old_excerpt.range.context.clone(),
3008                        )
3009                        .map(|edit| {
3010                            let excerpt_old_start = cursor.start().1;
3011                            let excerpt_new_start =
3012                                ExcerptOffset::new(new_excerpts.summary().text.len);
3013                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3014                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3015                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3016                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3017                            Edit {
3018                                old: old_start..old_end,
3019                                new: new_start..new_end,
3020                            }
3021                        }),
3022                );
3023
3024                new_excerpt = Excerpt::new(
3025                    old_excerpt.id,
3026                    locator.clone(),
3027                    buffer_id,
3028                    buffer.snapshot(),
3029                    old_excerpt.range.clone(),
3030                    old_excerpt.has_trailing_newline,
3031                );
3032            } else {
3033                new_excerpt = old_excerpt.clone();
3034                new_excerpt.buffer = buffer.snapshot();
3035            }
3036
3037            new_excerpts.push(new_excerpt, &());
3038            cursor.next(&());
3039        }
3040        new_excerpts.append(cursor.suffix(&()), &());
3041
3042        drop(cursor);
3043        snapshot.excerpts = new_excerpts;
3044
3045        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3046    }
3047
3048    fn sync_diff_transforms(
3049        &self,
3050        snapshot: &mut MultiBufferSnapshot,
3051        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3052        change_kind: DiffChangeKind,
3053    ) {
3054        if excerpt_edits.is_empty() {
3055            return;
3056        }
3057
3058        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3059        let mut old_diff_transforms = snapshot
3060            .diff_transforms
3061            .cursor::<(ExcerptOffset, usize)>(&());
3062        let mut new_diff_transforms = SumTree::default();
3063        let mut old_expanded_hunks = HashSet::default();
3064        let mut output_edits = Vec::new();
3065        let mut output_delta = 0_isize;
3066        let mut at_transform_boundary = true;
3067        let mut end_of_current_insert = None;
3068
3069        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3070        while let Some(edit) = excerpt_edits.next() {
3071            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
3072            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3073                excerpts.prev(&());
3074            }
3075
3076            // Keep any transforms that are before the edit.
3077            if at_transform_boundary {
3078                at_transform_boundary = false;
3079                let transforms_before_edit =
3080                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
3081                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3082                if let Some(transform) = old_diff_transforms.item() {
3083                    if old_diff_transforms.end(&()).0 == edit.old.start
3084                        && old_diff_transforms.start().0 < edit.old.start
3085                    {
3086                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3087                        old_diff_transforms.next(&());
3088                    }
3089                }
3090            }
3091
3092            // Compute the start of the edit in output coordinates.
3093            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3094            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3095            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3096
3097            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3098                &edit,
3099                &mut excerpts,
3100                &mut old_diff_transforms,
3101                &mut new_diff_transforms,
3102                &mut end_of_current_insert,
3103                &mut old_expanded_hunks,
3104                &snapshot,
3105                change_kind,
3106            );
3107
3108            // Compute the end of the edit in output coordinates.
3109            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3110            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3111            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3112            let edit_new_end =
3113                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3114            let output_edit = Edit {
3115                old: edit_old_start..edit_old_end,
3116                new: edit_new_start..edit_new_end,
3117            };
3118
3119            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3120            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3121            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3122                output_edits.push(output_edit);
3123            }
3124
3125            // If this is the last edit that intersects the current diff transform,
3126            // then recreate the content up to the end of this transform, to prepare
3127            // for reusing additional slices of the old transforms.
3128            if excerpt_edits.peek().map_or(true, |next_edit| {
3129                next_edit.old.start >= old_diff_transforms.end(&()).0
3130            }) {
3131                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3132                    && match old_diff_transforms.item() {
3133                        Some(DiffTransform::BufferContent {
3134                            inserted_hunk_info: Some(hunk),
3135                            ..
3136                        }) => excerpts.item().is_some_and(|excerpt| {
3137                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3138                        }),
3139                        _ => true,
3140                    };
3141
3142                let mut excerpt_offset = edit.new.end;
3143                if !keep_next_old_transform {
3144                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
3145                    old_diff_transforms.next(&());
3146                }
3147
3148                old_expanded_hunks.clear();
3149                self.push_buffer_content_transform(
3150                    &snapshot,
3151                    &mut new_diff_transforms,
3152                    excerpt_offset,
3153                    end_of_current_insert,
3154                );
3155                at_transform_boundary = true;
3156            }
3157        }
3158
3159        // Keep any transforms that are after the last edit.
3160        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
3161
3162        // Ensure there's always at least one buffer content transform.
3163        if new_diff_transforms.is_empty() {
3164            new_diff_transforms.push(
3165                DiffTransform::BufferContent {
3166                    summary: Default::default(),
3167                    inserted_hunk_info: None,
3168                },
3169                &(),
3170            );
3171        }
3172
3173        self.subscriptions.publish(output_edits);
3174        drop(old_diff_transforms);
3175        drop(excerpts);
3176        snapshot.diff_transforms = new_diff_transforms;
3177        snapshot.edit_count += 1;
3178
3179        #[cfg(any(test, feature = "test-support"))]
3180        snapshot.check_invariants();
3181    }
3182
3183    fn recompute_diff_transforms_for_edit(
3184        &self,
3185        edit: &Edit<TypedOffset<Excerpt>>,
3186        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3187        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
3188        new_diff_transforms: &mut SumTree<DiffTransform>,
3189        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3190        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3191        snapshot: &MultiBufferSnapshot,
3192        change_kind: DiffChangeKind,
3193    ) -> bool {
3194        log::trace!(
3195            "recomputing diff transform for edit {:?} => {:?}",
3196            edit.old.start.value..edit.old.end.value,
3197            edit.new.start.value..edit.new.end.value
3198        );
3199
3200        // Record which hunks were previously expanded.
3201        while let Some(item) = old_diff_transforms.item() {
3202            if let Some(hunk_info) = item.hunk_info() {
3203                log::trace!(
3204                    "previously expanded hunk at {}",
3205                    old_diff_transforms.start().0
3206                );
3207                old_expanded_hunks.insert(hunk_info);
3208            }
3209            if old_diff_transforms.end(&()).0 > edit.old.end {
3210                break;
3211            }
3212            old_diff_transforms.next(&());
3213        }
3214
3215        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3216        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3217        if old_expanded_hunks.is_empty()
3218            && change_kind == DiffChangeKind::BufferEdited
3219            && !all_diff_hunks_expanded
3220        {
3221            return false;
3222        }
3223
3224        // Visit each excerpt that intersects the edit.
3225        let mut did_expand_hunks = false;
3226        while let Some(excerpt) = excerpts.item() {
3227            // Recompute the expanded hunks in the portion of the excerpt that
3228            // intersects the edit.
3229            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3230                let buffer = &excerpt.buffer;
3231                let excerpt_start = *excerpts.start();
3232                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3233                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3234                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3235                let edit_buffer_start =
3236                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3237                let edit_buffer_end =
3238                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3239                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3240                let edit_anchor_range =
3241                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3242
3243                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3244                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3245                        continue;
3246                    }
3247
3248                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3249                    if hunk_buffer_range.start < excerpt_buffer_start {
3250                        log::trace!("skipping hunk that starts before excerpt");
3251                        continue;
3252                    }
3253
3254                    let hunk_info = DiffTransformHunkInfo {
3255                        excerpt_id: excerpt.id,
3256                        hunk_start_anchor: hunk.buffer_range.start,
3257                        hunk_secondary_status: hunk.secondary_status,
3258                    };
3259
3260                    let hunk_excerpt_start = excerpt_start
3261                        + ExcerptOffset::new(
3262                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3263                        );
3264                    let hunk_excerpt_end = excerpt_end.min(
3265                        excerpt_start
3266                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3267                    );
3268
3269                    self.push_buffer_content_transform(
3270                        snapshot,
3271                        new_diff_transforms,
3272                        hunk_excerpt_start,
3273                        *end_of_current_insert,
3274                    );
3275
3276                    // For every existing hunk, determine if it was previously expanded
3277                    // and if it should currently be expanded.
3278                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3279                    let should_expand_hunk = match &change_kind {
3280                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3281                            was_previously_expanded || all_diff_hunks_expanded
3282                        }
3283                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3284                            let intersects = hunk_buffer_range.is_empty()
3285                                || hunk_buffer_range.end > edit_buffer_start;
3286                            if *expand {
3287                                intersects || was_previously_expanded || all_diff_hunks_expanded
3288                            } else {
3289                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3290                            }
3291                        }
3292                        _ => was_previously_expanded || all_diff_hunks_expanded,
3293                    };
3294
3295                    if should_expand_hunk {
3296                        did_expand_hunks = true;
3297                        log::trace!(
3298                            "expanding hunk {:?}, excerpt:{:?}",
3299                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3300                            excerpt.id
3301                        );
3302
3303                        if !hunk.diff_base_byte_range.is_empty()
3304                            && hunk_buffer_range.start >= edit_buffer_start
3305                            && hunk_buffer_range.start <= excerpt_buffer_end
3306                        {
3307                            let base_text = diff.base_text();
3308                            let mut text_cursor =
3309                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3310                            let mut base_text_summary =
3311                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3312
3313                            let mut has_trailing_newline = false;
3314                            if base_text_summary.last_line_chars > 0 {
3315                                base_text_summary += TextSummary::newline();
3316                                has_trailing_newline = true;
3317                            }
3318
3319                            new_diff_transforms.push(
3320                                DiffTransform::DeletedHunk {
3321                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3322                                    summary: base_text_summary,
3323                                    buffer_id: excerpt.buffer_id,
3324                                    hunk_info,
3325                                    has_trailing_newline,
3326                                },
3327                                &(),
3328                            );
3329                        }
3330
3331                        if !hunk_buffer_range.is_empty() {
3332                            *end_of_current_insert =
3333                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3334                        }
3335                    }
3336                }
3337            }
3338
3339            if excerpts.end(&()) <= edit.new.end {
3340                excerpts.next(&());
3341            } else {
3342                break;
3343            }
3344        }
3345
3346        did_expand_hunks || !old_expanded_hunks.is_empty()
3347    }
3348
3349    fn append_diff_transforms(
3350        &self,
3351        new_transforms: &mut SumTree<DiffTransform>,
3352        subtree: SumTree<DiffTransform>,
3353    ) {
3354        if let Some(DiffTransform::BufferContent {
3355            inserted_hunk_info,
3356            summary,
3357        }) = subtree.first()
3358        {
3359            if self.extend_last_buffer_content_transform(
3360                new_transforms,
3361                *inserted_hunk_info,
3362                *summary,
3363            ) {
3364                let mut cursor = subtree.cursor::<()>(&());
3365                cursor.next(&());
3366                cursor.next(&());
3367                new_transforms.append(cursor.suffix(&()), &());
3368                return;
3369            }
3370        }
3371        new_transforms.append(subtree, &());
3372    }
3373
3374    fn push_diff_transform(
3375        &self,
3376        new_transforms: &mut SumTree<DiffTransform>,
3377        transform: DiffTransform,
3378    ) {
3379        if let DiffTransform::BufferContent {
3380            inserted_hunk_info: inserted_hunk_anchor,
3381            summary,
3382        } = transform
3383        {
3384            if self.extend_last_buffer_content_transform(
3385                new_transforms,
3386                inserted_hunk_anchor,
3387                summary,
3388            ) {
3389                return;
3390            }
3391        }
3392        new_transforms.push(transform, &());
3393    }
3394
3395    fn push_buffer_content_transform(
3396        &self,
3397        old_snapshot: &MultiBufferSnapshot,
3398        new_transforms: &mut SumTree<DiffTransform>,
3399        end_offset: ExcerptOffset,
3400        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3401    ) {
3402        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3403            (end_offset.min(insertion_end_offset), Some(hunk_info))
3404        });
3405        let unchanged_region = [(end_offset, None)];
3406
3407        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3408        {
3409            let start_offset = new_transforms.summary().excerpt_len();
3410            if end_offset <= start_offset {
3411                continue;
3412            }
3413            let summary_to_add = old_snapshot
3414                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3415
3416            if !self.extend_last_buffer_content_transform(
3417                new_transforms,
3418                inserted_hunk_info,
3419                summary_to_add,
3420            ) {
3421                new_transforms.push(
3422                    DiffTransform::BufferContent {
3423                        summary: summary_to_add,
3424                        inserted_hunk_info,
3425                    },
3426                    &(),
3427                )
3428            }
3429        }
3430    }
3431
3432    fn extend_last_buffer_content_transform(
3433        &self,
3434        new_transforms: &mut SumTree<DiffTransform>,
3435        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3436        summary_to_add: TextSummary,
3437    ) -> bool {
3438        let mut did_extend = false;
3439        new_transforms.update_last(
3440            |last_transform| {
3441                if let DiffTransform::BufferContent {
3442                    summary,
3443                    inserted_hunk_info: inserted_hunk_anchor,
3444                } = last_transform
3445                {
3446                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3447                        *summary += summary_to_add;
3448                        did_extend = true;
3449                    }
3450                }
3451            },
3452            &(),
3453        );
3454        did_extend
3455    }
3456}
3457
3458#[cfg(any(test, feature = "test-support"))]
3459impl MultiBuffer {
3460    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3461        let buffer = cx.new(|cx| Buffer::local(text, cx));
3462        cx.new(|cx| Self::singleton(buffer, cx))
3463    }
3464
3465    pub fn build_multi<const COUNT: usize>(
3466        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3467        cx: &mut gpui::App,
3468    ) -> Entity<Self> {
3469        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3470        for (text, ranges) in excerpts {
3471            let buffer = cx.new(|cx| Buffer::local(text, cx));
3472            let excerpt_ranges = ranges
3473                .into_iter()
3474                .map(|range| ExcerptRange::new(range.clone()));
3475            multi.update(cx, |multi, cx| {
3476                multi.push_excerpts(buffer, excerpt_ranges, cx)
3477            });
3478        }
3479
3480        multi
3481    }
3482
3483    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3484        cx.new(|cx| Self::singleton(buffer, cx))
3485    }
3486
3487    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3488        cx.new(|cx| {
3489            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3490            let mutation_count = rng.gen_range(1..=5);
3491            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3492            multibuffer
3493        })
3494    }
3495
3496    pub fn randomly_edit(
3497        &mut self,
3498        rng: &mut impl rand::Rng,
3499        edit_count: usize,
3500        cx: &mut Context<Self>,
3501    ) {
3502        use util::RandomCharIter;
3503
3504        let snapshot = self.read(cx);
3505        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3506        let mut last_end = None;
3507        for _ in 0..edit_count {
3508            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3509                break;
3510            }
3511
3512            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3513            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3514            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3515            last_end = Some(end);
3516
3517            let mut range = start..end;
3518            if rng.gen_bool(0.2) {
3519                mem::swap(&mut range.start, &mut range.end);
3520            }
3521
3522            let new_text_len = rng.gen_range(0..10);
3523            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3524
3525            edits.push((range, new_text.into()));
3526        }
3527        log::info!("mutating multi-buffer with {:?}", edits);
3528        drop(snapshot);
3529
3530        self.edit(edits, None, cx);
3531    }
3532
3533    pub fn randomly_edit_excerpts(
3534        &mut self,
3535        rng: &mut impl rand::Rng,
3536        mutation_count: usize,
3537        cx: &mut Context<Self>,
3538    ) {
3539        use rand::prelude::*;
3540        use std::env;
3541        use util::RandomCharIter;
3542
3543        let max_excerpts = env::var("MAX_EXCERPTS")
3544            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3545            .unwrap_or(5);
3546
3547        let mut buffers = Vec::new();
3548        for _ in 0..mutation_count {
3549            if rng.gen_bool(0.05) {
3550                log::info!("Clearing multi-buffer");
3551                self.clear(cx);
3552                continue;
3553            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3554                let ids = self.excerpt_ids();
3555                let mut excerpts = HashSet::default();
3556                for _ in 0..rng.gen_range(0..ids.len()) {
3557                    excerpts.extend(ids.choose(rng).copied());
3558                }
3559
3560                let line_count = rng.gen_range(0..5);
3561
3562                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3563
3564                self.expand_excerpts(
3565                    excerpts.iter().cloned(),
3566                    line_count,
3567                    ExpandExcerptDirection::UpAndDown,
3568                    cx,
3569                );
3570                continue;
3571            }
3572
3573            let excerpt_ids = self.excerpt_ids();
3574            if excerpt_ids.is_empty() || (rng.r#gen() && excerpt_ids.len() < max_excerpts) {
3575                let buffer_handle = if rng.r#gen() || self.buffers.borrow().is_empty() {
3576                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3577                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3578                    let buffer = buffers.last().unwrap().read(cx);
3579                    log::info!(
3580                        "Creating new buffer {} with text: {:?}",
3581                        buffer.remote_id(),
3582                        buffer.text()
3583                    );
3584                    buffers.last().unwrap().clone()
3585                } else {
3586                    self.buffers
3587                        .borrow()
3588                        .values()
3589                        .choose(rng)
3590                        .unwrap()
3591                        .buffer
3592                        .clone()
3593                };
3594
3595                let buffer = buffer_handle.read(cx);
3596                let buffer_text = buffer.text();
3597                let ranges = (0..rng.gen_range(0..5))
3598                    .map(|_| {
3599                        let end_ix =
3600                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3601                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3602                        ExcerptRange::new(start_ix..end_ix)
3603                    })
3604                    .collect::<Vec<_>>();
3605                log::info!(
3606                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3607                    buffer_handle.read(cx).remote_id(),
3608                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3609                    ranges
3610                        .iter()
3611                        .map(|r| &buffer_text[r.context.clone()])
3612                        .collect::<Vec<_>>()
3613                );
3614
3615                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3616                log::info!("Inserted with ids: {:?}", excerpt_id);
3617            } else {
3618                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3619                let mut excerpts_to_remove = excerpt_ids
3620                    .choose_multiple(rng, remove_count)
3621                    .cloned()
3622                    .collect::<Vec<_>>();
3623                let snapshot = self.snapshot.borrow();
3624                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3625                drop(snapshot);
3626                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3627                self.remove_excerpts(excerpts_to_remove, cx);
3628            }
3629        }
3630    }
3631
3632    pub fn randomly_mutate(
3633        &mut self,
3634        rng: &mut impl rand::Rng,
3635        mutation_count: usize,
3636        cx: &mut Context<Self>,
3637    ) {
3638        use rand::prelude::*;
3639
3640        if rng.gen_bool(0.7) || self.singleton {
3641            let buffer = self
3642                .buffers
3643                .borrow()
3644                .values()
3645                .choose(rng)
3646                .map(|state| state.buffer.clone());
3647
3648            if let Some(buffer) = buffer {
3649                buffer.update(cx, |buffer, cx| {
3650                    if rng.r#gen() {
3651                        buffer.randomly_edit(rng, mutation_count, cx);
3652                    } else {
3653                        buffer.randomly_undo_redo(rng, cx);
3654                    }
3655                });
3656            } else {
3657                self.randomly_edit(rng, mutation_count, cx);
3658            }
3659        } else {
3660            self.randomly_edit_excerpts(rng, mutation_count, cx);
3661        }
3662
3663        self.check_invariants(cx);
3664    }
3665
3666    fn check_invariants(&self, cx: &App) {
3667        self.read(cx).check_invariants();
3668    }
3669}
3670
3671impl EventEmitter<Event> for MultiBuffer {}
3672
3673impl MultiBufferSnapshot {
3674    pub fn text(&self) -> String {
3675        self.chunks(0..self.len(), false)
3676            .map(|chunk| chunk.text)
3677            .collect()
3678    }
3679
3680    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3681        self.reversed_chunks_in_range(0..position.to_offset(self))
3682            .flat_map(|c| c.chars().rev())
3683    }
3684
3685    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3686        let mut cursor = self.cursor::<usize>();
3687        cursor.seek(&range.end);
3688        let current_chunks = cursor.region().as_ref().map(|region| {
3689            let start_overshoot = range.start.saturating_sub(region.range.start);
3690            let end_overshoot = range.end - region.range.start;
3691            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3692            let start = region.buffer_range.start + start_overshoot;
3693            region.buffer.reversed_chunks_in_range(start..end)
3694        });
3695        ReversedMultiBufferChunks {
3696            cursor,
3697            current_chunks,
3698            start: range.start,
3699            offset: range.end,
3700        }
3701    }
3702
3703    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3704        let offset = position.to_offset(self);
3705        self.text_for_range(offset..self.len())
3706            .flat_map(|chunk| chunk.chars())
3707    }
3708
3709    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3710        self.chunks(range, false).map(|chunk| chunk.text)
3711    }
3712
3713    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3714        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3715            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3716    }
3717
3718    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3719    where
3720        T: ToOffset,
3721    {
3722        let position = position.to_offset(self);
3723        position == self.clip_offset(position, Bias::Left)
3724            && self
3725                .bytes_in_range(position..self.len())
3726                .flatten()
3727                .copied()
3728                .take(needle.len())
3729                .eq(needle.bytes())
3730    }
3731
3732    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3733        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3734    }
3735
3736    pub fn diff_hunks_in_range<T: ToPoint>(
3737        &self,
3738        range: Range<T>,
3739    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3740        let query_range = range.start.to_point(self)..range.end.to_point(self);
3741        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3742            let diff = self.diffs.get(&buffer.remote_id())?;
3743            let buffer_start = buffer.anchor_before(buffer_range.start);
3744            let buffer_end = buffer.anchor_after(buffer_range.end);
3745            Some(
3746                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3747                    .filter_map(|hunk| {
3748                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3749                            return None;
3750                        }
3751                        Some((hunk.range.clone(), hunk))
3752                    }),
3753            )
3754        })
3755        .filter_map(move |(range, hunk, excerpt)| {
3756            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3757            {
3758                return None;
3759            }
3760            let end_row = if range.end.column == 0 {
3761                range.end.row
3762            } else {
3763                range.end.row + 1
3764            };
3765            Some(MultiBufferDiffHunk {
3766                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3767                buffer_id: excerpt.buffer_id,
3768                excerpt_id: excerpt.id,
3769                buffer_range: hunk.buffer_range.clone(),
3770                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3771                secondary_status: hunk.secondary_status,
3772            })
3773        })
3774    }
3775
3776    pub fn excerpt_ids_for_range<T: ToOffset>(
3777        &self,
3778        range: Range<T>,
3779    ) -> impl Iterator<Item = ExcerptId> + '_ {
3780        let range = range.start.to_offset(self)..range.end.to_offset(self);
3781        let mut cursor = self.cursor::<usize>();
3782        cursor.seek(&range.start);
3783        std::iter::from_fn(move || {
3784            let region = cursor.region()?;
3785            if region.range.start >= range.end {
3786                return None;
3787            }
3788            cursor.next_excerpt();
3789            Some(region.excerpt.id)
3790        })
3791    }
3792
3793    pub fn buffer_ids_for_range<T: ToOffset>(
3794        &self,
3795        range: Range<T>,
3796    ) -> impl Iterator<Item = BufferId> + '_ {
3797        let range = range.start.to_offset(self)..range.end.to_offset(self);
3798        let mut cursor = self.cursor::<usize>();
3799        cursor.seek(&range.start);
3800        std::iter::from_fn(move || {
3801            let region = cursor.region()?;
3802            if region.range.start > range.end
3803                || region.range.start == range.end && region.range.start > range.start
3804            {
3805                return None;
3806            }
3807            cursor.next_excerpt();
3808            Some(region.excerpt.buffer_id)
3809        })
3810    }
3811
3812    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3813        &self,
3814        ranges: impl Iterator<Item = Range<T>>,
3815    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3816        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3817    }
3818
3819    pub fn range_to_buffer_ranges<T: ToOffset>(
3820        &self,
3821        range: Range<T>,
3822    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3823        let start = range.start.to_offset(&self);
3824        let end = range.end.to_offset(&self);
3825
3826        let mut cursor = self.cursor::<usize>();
3827        cursor.seek(&start);
3828
3829        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3830        while let Some(region) = cursor.region() {
3831            if region.range.start > end {
3832                break;
3833            }
3834            if region.is_main_buffer {
3835                let start_overshoot = start.saturating_sub(region.range.start);
3836                let end_overshoot = end.saturating_sub(region.range.start);
3837                let start = region
3838                    .buffer_range
3839                    .end
3840                    .min(region.buffer_range.start + start_overshoot);
3841                let end = region
3842                    .buffer_range
3843                    .end
3844                    .min(region.buffer_range.start + end_overshoot);
3845                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3846                    *excerpt_id == region.excerpt.id && prev_range.end == start
3847                }) {
3848                    prev.1.end = end;
3849                } else {
3850                    result.push((region.buffer, start..end, region.excerpt.id));
3851                }
3852            }
3853            cursor.next();
3854        }
3855        result
3856    }
3857
3858    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3859        &self,
3860        range: Range<T>,
3861    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3862        let start = range.start.to_offset(&self);
3863        let end = range.end.to_offset(&self);
3864
3865        let mut cursor = self.cursor::<usize>();
3866        cursor.seek(&start);
3867
3868        std::iter::from_fn(move || {
3869            let region = cursor.region()?;
3870            if region.range.start > end {
3871                return None;
3872            }
3873            let start_overshoot = start.saturating_sub(region.range.start);
3874            let end_overshoot = end.saturating_sub(region.range.start);
3875            let start = region
3876                .buffer_range
3877                .end
3878                .min(region.buffer_range.start + start_overshoot);
3879            let end = region
3880                .buffer_range
3881                .end
3882                .min(region.buffer_range.start + end_overshoot);
3883
3884            let region_excerpt_id = region.excerpt.id;
3885            let deleted_hunk_anchor = if region.is_main_buffer {
3886                None
3887            } else {
3888                Some(self.anchor_before(region.range.start))
3889            };
3890            let result = (
3891                region.buffer,
3892                start..end,
3893                region_excerpt_id,
3894                deleted_hunk_anchor,
3895            );
3896            cursor.next();
3897            Some(result)
3898        })
3899    }
3900
3901    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3902    /// coordinates.
3903    ///
3904    /// The given callback will be called for every excerpt intersecting the given range. It will
3905    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3906    /// The callback should return an iterator of metadata items from that buffer, each paired
3907    /// with a buffer range.
3908    ///
3909    /// The returned iterator yields each of these metadata items, paired with its range in
3910    /// multi-buffer coordinates.
3911    fn lift_buffer_metadata<'a, D, M, I>(
3912        &'a self,
3913        query_range: Range<D>,
3914        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3915    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3916    where
3917        I: Iterator<Item = (Range<D>, M)> + 'a,
3918        D: TextDimension + Ord + Sub<D, Output = D>,
3919    {
3920        let max_position = D::from_text_summary(&self.text_summary());
3921        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3922        let mut cursor = self.cursor::<D>();
3923
3924        // Find the excerpt and buffer offset where the given range ends.
3925        cursor.seek(&query_range.end);
3926        let mut range_end = None;
3927        while let Some(region) = cursor.region() {
3928            if region.is_main_buffer {
3929                let mut buffer_end = region.buffer_range.start;
3930                let overshoot = if query_range.end > region.range.start {
3931                    query_range.end - region.range.start
3932                } else {
3933                    D::default()
3934                };
3935                buffer_end.add_assign(&overshoot);
3936                range_end = Some((region.excerpt.id, buffer_end));
3937                break;
3938            }
3939            cursor.next();
3940        }
3941
3942        cursor.seek(&query_range.start);
3943
3944        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3945            if region.range.start > D::zero(&()) {
3946                cursor.prev()
3947            }
3948        }
3949
3950        iter::from_fn(move || {
3951            loop {
3952                let excerpt = cursor.excerpt()?;
3953
3954                // If we have already retrieved metadata for this excerpt, continue to use it.
3955                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3956                    .as_mut()
3957                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3958                {
3959                    Some(metadata)
3960                }
3961                // Otherwise, compute the intersection of the input range with the excerpt's range,
3962                // and retrieve the metadata for the resulting range.
3963                else {
3964                    let region = cursor.region()?;
3965                    let mut buffer_start;
3966                    if region.is_main_buffer {
3967                        buffer_start = region.buffer_range.start;
3968                        if query_range.start > region.range.start {
3969                            let overshoot = query_range.start - region.range.start;
3970                            buffer_start.add_assign(&overshoot);
3971                        }
3972                        buffer_start = buffer_start.min(region.buffer_range.end);
3973                    } else {
3974                        buffer_start = cursor.main_buffer_position()?;
3975                    };
3976                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
3977                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
3978                        if excerpt.id == end_excerpt_id {
3979                            buffer_end = buffer_end.min(end_buffer_offset);
3980                        }
3981                    }
3982
3983                    if let Some(iterator) =
3984                        get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
3985                    {
3986                        Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
3987                    } else {
3988                        None
3989                    }
3990                };
3991
3992                // Visit each metadata item.
3993                if let Some((metadata_buffer_range, metadata)) =
3994                    metadata_iter.and_then(Iterator::next)
3995                {
3996                    // Find the multibuffer regions that contain the start and end of
3997                    // the metadata item's range.
3998                    if metadata_buffer_range.start > D::default() {
3999                        while let Some(region) = cursor.region() {
4000                            if region.is_main_buffer
4001                                && (region.buffer_range.end >= metadata_buffer_range.start
4002                                    || cursor.is_at_end_of_excerpt())
4003                            {
4004                                break;
4005                            }
4006                            cursor.next();
4007                        }
4008                    }
4009                    let start_region = cursor.region()?;
4010                    while let Some(region) = cursor.region() {
4011                        if region.is_main_buffer
4012                            && (region.buffer_range.end > metadata_buffer_range.end
4013                                || cursor.is_at_end_of_excerpt())
4014                        {
4015                            break;
4016                        }
4017                        cursor.next();
4018                    }
4019                    let end_region = cursor.region();
4020
4021                    // Convert the metadata item's range into multibuffer coordinates.
4022                    let mut start_position = start_region.range.start;
4023                    let region_buffer_start = start_region.buffer_range.start;
4024                    if start_region.is_main_buffer
4025                        && metadata_buffer_range.start > region_buffer_start
4026                    {
4027                        start_position
4028                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4029                        start_position = start_position.min(start_region.range.end);
4030                    }
4031
4032                    let mut end_position = max_position;
4033                    if let Some(end_region) = &end_region {
4034                        end_position = end_region.range.start;
4035                        debug_assert!(end_region.is_main_buffer);
4036                        let region_buffer_start = end_region.buffer_range.start;
4037                        if metadata_buffer_range.end > region_buffer_start {
4038                            end_position
4039                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4040                        }
4041                        end_position = end_position.min(end_region.range.end);
4042                    }
4043
4044                    if start_position <= query_range.end && end_position >= query_range.start {
4045                        return Some((start_position..end_position, metadata, excerpt));
4046                    }
4047                }
4048                // When there are no more metadata items for this excerpt, move to the next excerpt.
4049                else {
4050                    current_excerpt_metadata.take();
4051                    if let Some((end_excerpt_id, _)) = range_end {
4052                        if excerpt.id == end_excerpt_id {
4053                            return None;
4054                        }
4055                    }
4056                    cursor.next_excerpt();
4057                }
4058            }
4059        })
4060    }
4061
4062    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4063        let offset = position.to_offset(self);
4064
4065        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4066        cursor.seek(&DimensionPair {
4067            key: offset,
4068            value: None,
4069        });
4070        cursor.seek_to_start_of_current_excerpt();
4071        let excerpt = cursor.excerpt()?;
4072
4073        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4074        let current_position = self
4075            .anchor_before(offset)
4076            .text_anchor
4077            .to_offset(&excerpt.buffer);
4078        let excerpt_end = excerpt
4079            .buffer
4080            .anchor_before(excerpt_end.min(current_position));
4081
4082        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4083            for hunk in diff.hunks_intersecting_range_rev(
4084                excerpt.range.context.start..excerpt_end,
4085                &excerpt.buffer,
4086            ) {
4087                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4088                if hunk_end >= current_position {
4089                    continue;
4090                }
4091                let start =
4092                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4093                        .to_point(&self);
4094                return Some(MultiBufferRow(start.row));
4095            }
4096        }
4097
4098        loop {
4099            cursor.prev_excerpt();
4100            let excerpt = cursor.excerpt()?;
4101
4102            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4103                continue;
4104            };
4105            let mut hunks =
4106                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4107            let Some(hunk) = hunks.next() else {
4108                continue;
4109            };
4110            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4111                .to_point(&self);
4112            return Some(MultiBufferRow(start.row));
4113        }
4114    }
4115
4116    pub fn has_diff_hunks(&self) -> bool {
4117        self.diffs.values().any(|diff| !diff.is_empty())
4118    }
4119
4120    pub fn surrounding_word<T: ToOffset>(
4121        &self,
4122        start: T,
4123        for_completion: bool,
4124    ) -> (Range<usize>, Option<CharKind>) {
4125        let mut start = start.to_offset(self);
4126        let mut end = start;
4127        let mut next_chars = self.chars_at(start).peekable();
4128        let mut prev_chars = self.reversed_chars_at(start).peekable();
4129
4130        let classifier = self
4131            .char_classifier_at(start)
4132            .for_completion(for_completion);
4133
4134        let word_kind = cmp::max(
4135            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4136            next_chars.peek().copied().map(|c| classifier.kind(c)),
4137        );
4138
4139        for ch in prev_chars {
4140            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4141                start -= ch.len_utf8();
4142            } else {
4143                break;
4144            }
4145        }
4146
4147        for ch in next_chars {
4148            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4149                end += ch.len_utf8();
4150            } else {
4151                break;
4152            }
4153        }
4154
4155        (start..end, word_kind)
4156    }
4157
4158    pub fn is_singleton(&self) -> bool {
4159        self.singleton
4160    }
4161
4162    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4163        if self.singleton {
4164            self.excerpts
4165                .iter()
4166                .next()
4167                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4168        } else {
4169            None
4170        }
4171    }
4172
4173    pub fn len(&self) -> usize {
4174        self.diff_transforms.summary().output.len
4175    }
4176
4177    pub fn is_empty(&self) -> bool {
4178        self.excerpts.summary().text.len == 0
4179    }
4180
4181    pub fn widest_line_number(&self) -> u32 {
4182        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4183        self.excerpts.summary().widest_line_number + 1
4184    }
4185
4186    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
4187        let range = range.start.to_offset(self)..range.end.to_offset(self);
4188        let mut excerpts = self.cursor::<usize>();
4189        excerpts.seek(&range.start);
4190
4191        let mut chunk;
4192        let mut has_trailing_newline;
4193        let excerpt_bytes;
4194        if let Some(region) = excerpts.region() {
4195            let mut bytes = region.buffer.bytes_in_range(
4196                region.buffer_range.start + range.start - region.range.start
4197                    ..(region.buffer_range.start + range.end - region.range.start)
4198                        .min(region.buffer_range.end),
4199            );
4200            chunk = bytes.next().unwrap_or(&[][..]);
4201            excerpt_bytes = Some(bytes);
4202            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4203            if chunk.is_empty() && has_trailing_newline {
4204                chunk = b"\n";
4205                has_trailing_newline = false;
4206            }
4207        } else {
4208            chunk = &[][..];
4209            excerpt_bytes = None;
4210            has_trailing_newline = false;
4211        };
4212
4213        MultiBufferBytes {
4214            range,
4215            cursor: excerpts,
4216            excerpt_bytes,
4217            has_trailing_newline,
4218            chunk,
4219        }
4220    }
4221
4222    pub fn reversed_bytes_in_range<T: ToOffset>(
4223        &self,
4224        range: Range<T>,
4225    ) -> ReversedMultiBufferBytes {
4226        let range = range.start.to_offset(self)..range.end.to_offset(self);
4227        let mut chunks = self.reversed_chunks_in_range(range.clone());
4228        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4229        ReversedMultiBufferBytes {
4230            range,
4231            chunks,
4232            chunk,
4233        }
4234    }
4235
4236    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4237        let mut cursor = self.cursor::<Point>();
4238        cursor.seek(&Point::new(start_row.0, 0));
4239        let mut result = MultiBufferRows {
4240            point: Point::new(0, 0),
4241            is_empty: self.excerpts.is_empty(),
4242            is_singleton: self.is_singleton(),
4243            cursor,
4244        };
4245        result.seek(start_row);
4246        result
4247    }
4248
4249    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4250        let mut chunks = MultiBufferChunks {
4251            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4252            range: 0..0,
4253            excerpts: self.excerpts.cursor(&()),
4254            diff_transforms: self.diff_transforms.cursor(&()),
4255            diffs: &self.diffs,
4256            diff_base_chunks: None,
4257            excerpt_chunks: None,
4258            buffer_chunk: None,
4259            language_aware,
4260        };
4261        let range = range.start.to_offset(self)..range.end.to_offset(self);
4262        chunks.seek(range);
4263        chunks
4264    }
4265
4266    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4267        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4268    }
4269
4270    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4271        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4272    }
4273
4274    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4275        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4276    }
4277
4278    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4279        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4280            buffer.clip_point_utf16(Unclipped(point), bias)
4281        })
4282    }
4283
4284    pub fn offset_to_point(&self, offset: usize) -> Point {
4285        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4286    }
4287
4288    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4289        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4290    }
4291
4292    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4293        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4294    }
4295
4296    pub fn point_to_offset(&self, point: Point) -> usize {
4297        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4298    }
4299
4300    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4301        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4302    }
4303
4304    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4305        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4306    }
4307
4308    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4309        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4310    }
4311
4312    fn clip_dimension<D>(
4313        &self,
4314        position: D,
4315        bias: Bias,
4316        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4317    ) -> D
4318    where
4319        D: TextDimension + Ord + Sub<D, Output = D>,
4320    {
4321        let mut cursor = self.cursor();
4322        cursor.seek(&position);
4323        if let Some(region) = cursor.region() {
4324            if position >= region.range.end {
4325                return region.range.end;
4326            }
4327            let overshoot = position - region.range.start;
4328            let mut buffer_position = region.buffer_range.start;
4329            buffer_position.add_assign(&overshoot);
4330            let clipped_buffer_position =
4331                clip_buffer_position(&region.buffer, buffer_position, bias);
4332            let mut position = region.range.start;
4333            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4334            position
4335        } else {
4336            D::from_text_summary(&self.text_summary())
4337        }
4338    }
4339
4340    fn convert_dimension<D1, D2>(
4341        &self,
4342        key: D1,
4343        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4344    ) -> D2
4345    where
4346        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4347        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4348    {
4349        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4350        cursor.seek(&DimensionPair { key, value: None });
4351        if let Some(region) = cursor.region() {
4352            if key >= region.range.end.key {
4353                return region.range.end.value.unwrap();
4354            }
4355            let start_key = region.range.start.key;
4356            let start_value = region.range.start.value.unwrap();
4357            let buffer_start_key = region.buffer_range.start.key;
4358            let buffer_start_value = region.buffer_range.start.value.unwrap();
4359            let mut buffer_key = buffer_start_key;
4360            buffer_key.add_assign(&(key - start_key));
4361            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4362            let mut result = start_value;
4363            result.add_assign(&(buffer_value - buffer_start_value));
4364            result
4365        } else {
4366            D2::from_text_summary(&self.text_summary())
4367        }
4368    }
4369
4370    pub fn point_to_buffer_offset<T: ToOffset>(
4371        &self,
4372        point: T,
4373    ) -> Option<(&BufferSnapshot, usize)> {
4374        let offset = point.to_offset(self);
4375        let mut cursor = self.cursor::<usize>();
4376        cursor.seek(&offset);
4377        let region = cursor.region()?;
4378        let overshoot = offset - region.range.start;
4379        let buffer_offset = region.buffer_range.start + overshoot;
4380        if buffer_offset == region.buffer.len() + 1
4381            && region.has_trailing_newline
4382            && !region.is_main_buffer
4383        {
4384            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4385        } else if buffer_offset > region.buffer.len() {
4386            return None;
4387        }
4388        Some((region.buffer, buffer_offset))
4389    }
4390
4391    pub fn point_to_buffer_point(
4392        &self,
4393        point: Point,
4394    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4395        let mut cursor = self.cursor::<Point>();
4396        cursor.seek(&point);
4397        let region = cursor.region()?;
4398        let overshoot = point - region.range.start;
4399        let buffer_point = region.buffer_range.start + overshoot;
4400        let excerpt = cursor.excerpt()?;
4401        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4402            && region.has_trailing_newline
4403            && !region.is_main_buffer
4404        {
4405            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4406        } else if buffer_point > region.buffer.max_point() {
4407            return None;
4408        }
4409        Some((region.buffer, buffer_point, excerpt.id))
4410    }
4411
4412    pub fn suggested_indents(
4413        &self,
4414        rows: impl IntoIterator<Item = u32>,
4415        cx: &App,
4416    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4417        let mut result = BTreeMap::new();
4418
4419        let mut rows_for_excerpt = Vec::new();
4420        let mut cursor = self.cursor::<Point>();
4421        let mut rows = rows.into_iter().peekable();
4422        let mut prev_row = u32::MAX;
4423        let mut prev_language_indent_size = IndentSize::default();
4424
4425        while let Some(row) = rows.next() {
4426            cursor.seek(&Point::new(row, 0));
4427            let Some(region) = cursor.region() else {
4428                continue;
4429            };
4430
4431            // Retrieve the language and indent size once for each disjoint region being indented.
4432            let single_indent_size = if row.saturating_sub(1) == prev_row {
4433                prev_language_indent_size
4434            } else {
4435                region
4436                    .buffer
4437                    .language_indent_size_at(Point::new(row, 0), cx)
4438            };
4439            prev_language_indent_size = single_indent_size;
4440            prev_row = row;
4441
4442            let start_buffer_row = region.buffer_range.start.row;
4443            let start_multibuffer_row = region.range.start.row;
4444            let end_multibuffer_row = region.range.end.row;
4445
4446            rows_for_excerpt.push(row);
4447            while let Some(next_row) = rows.peek().copied() {
4448                if end_multibuffer_row > next_row {
4449                    rows_for_excerpt.push(next_row);
4450                    rows.next();
4451                } else {
4452                    break;
4453                }
4454            }
4455
4456            let buffer_rows = rows_for_excerpt
4457                .drain(..)
4458                .map(|row| start_buffer_row + row - start_multibuffer_row);
4459            let buffer_indents = region
4460                .buffer
4461                .suggested_indents(buffer_rows, single_indent_size);
4462            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4463                (
4464                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4465                    indent,
4466                )
4467            });
4468            result.extend(multibuffer_indents);
4469        }
4470
4471        result
4472    }
4473
4474    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4475        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4476            let mut size = buffer.indent_size_for_line(range.start.row);
4477            size.len = size
4478                .len
4479                .min(range.end.column)
4480                .saturating_sub(range.start.column);
4481            size
4482        } else {
4483            IndentSize::spaces(0)
4484        }
4485    }
4486
4487    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4488        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4489            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4490        } else {
4491            LineIndent::spaces(0)
4492        }
4493    }
4494
4495    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4496        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4497
4498        if self.language_settings(cx).extend_comment_on_newline {
4499            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4500                let delimiters = language_scope.line_comment_prefixes();
4501                for delimiter in delimiters {
4502                    if *self
4503                        .chars_at(Point::new(row.0, indent.len() as u32))
4504                        .take(delimiter.chars().count())
4505                        .collect::<String>()
4506                        .as_str()
4507                        == **delimiter
4508                    {
4509                        indent.push_str(&delimiter);
4510                        break;
4511                    }
4512                }
4513            }
4514        }
4515
4516        indent
4517    }
4518
4519    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4520    where
4521        T: ToOffset,
4522    {
4523        for char in self.reversed_chars_at(position) {
4524            if !char.is_whitespace() {
4525                return false;
4526            }
4527            if char == '\n' {
4528                return true;
4529            }
4530        }
4531        return true;
4532    }
4533
4534    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4535        while row.0 > 0 {
4536            row.0 -= 1;
4537            if !self.is_line_blank(row) {
4538                return Some(row);
4539            }
4540        }
4541        None
4542    }
4543
4544    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4545        if let Some((_, range)) = self.buffer_line_for_row(row) {
4546            range.end.column - range.start.column
4547        } else {
4548            0
4549        }
4550    }
4551
4552    pub fn buffer_line_for_row(
4553        &self,
4554        row: MultiBufferRow,
4555    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4556        let mut cursor = self.cursor::<Point>();
4557        let point = Point::new(row.0, 0);
4558        cursor.seek(&point);
4559        let region = cursor.region()?;
4560        let overshoot = point.min(region.range.end) - region.range.start;
4561        let buffer_point = region.buffer_range.start + overshoot;
4562        if buffer_point.row > region.buffer_range.end.row {
4563            return None;
4564        }
4565        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4566        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4567            .min(region.buffer_range.end);
4568        Some((region.buffer, line_start..line_end))
4569    }
4570
4571    pub fn max_point(&self) -> Point {
4572        self.text_summary().lines
4573    }
4574
4575    pub fn max_row(&self) -> MultiBufferRow {
4576        MultiBufferRow(self.text_summary().lines.row)
4577    }
4578
4579    pub fn text_summary(&self) -> TextSummary {
4580        self.diff_transforms.summary().output
4581    }
4582
4583    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4584    where
4585        D: TextDimension,
4586        O: ToOffset,
4587    {
4588        let range = range.start.to_offset(self)..range.end.to_offset(self);
4589        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4590        cursor.seek(&range.start, Bias::Right, &());
4591
4592        let Some(first_transform) = cursor.item() else {
4593            return D::from_text_summary(&TextSummary::default());
4594        };
4595
4596        let diff_transform_start = cursor.start().0;
4597        let diff_transform_end = cursor.end(&()).0;
4598        let diff_start = range.start;
4599        let start_overshoot = diff_start - diff_transform_start;
4600        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4601
4602        let mut result = match first_transform {
4603            DiffTransform::BufferContent { .. } => {
4604                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4605                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4606                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4607            }
4608            DiffTransform::DeletedHunk {
4609                buffer_id,
4610                base_text_byte_range,
4611                has_trailing_newline,
4612                ..
4613            } => {
4614                let buffer_start = base_text_byte_range.start + start_overshoot;
4615                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4616                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4617                    panic!("{:?} is in non-existent deleted hunk", range.start)
4618                };
4619
4620                let include_trailing_newline =
4621                    *has_trailing_newline && range.end >= diff_transform_end;
4622                if include_trailing_newline {
4623                    buffer_end -= 1;
4624                }
4625
4626                let mut summary =
4627                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4628
4629                if include_trailing_newline {
4630                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4631                }
4632
4633                summary
4634            }
4635        };
4636        if range.end < diff_transform_end {
4637            return result;
4638        }
4639
4640        cursor.next(&());
4641        result.add_assign(&D::from_text_summary(&cursor.summary(
4642            &range.end,
4643            Bias::Right,
4644            &(),
4645        )));
4646
4647        let Some(last_transform) = cursor.item() else {
4648            return result;
4649        };
4650
4651        let overshoot = range.end - cursor.start().0;
4652        let suffix = match last_transform {
4653            DiffTransform::BufferContent { .. } => {
4654                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4655                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4656            }
4657            DiffTransform::DeletedHunk {
4658                base_text_byte_range,
4659                buffer_id,
4660                has_trailing_newline,
4661                ..
4662            } => {
4663                let buffer_end = base_text_byte_range.start + overshoot;
4664                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4665                    panic!("{:?} is in non-existent deleted hunk", range.end)
4666                };
4667
4668                let mut suffix = base_text
4669                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4670                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4671                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4672                }
4673                suffix
4674            }
4675        };
4676
4677        result.add_assign(&suffix);
4678        result
4679    }
4680
4681    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4682    where
4683        D: TextDimension,
4684    {
4685        // let mut range = range.start..range.end;
4686        let mut summary = D::zero(&());
4687        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4688        cursor.seek(&range.start, Bias::Right, &());
4689        if let Some(excerpt) = cursor.item() {
4690            let mut end_before_newline = cursor.end(&());
4691            if excerpt.has_trailing_newline {
4692                end_before_newline -= ExcerptOffset::new(1);
4693            }
4694
4695            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4696            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4697            let end_in_excerpt =
4698                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4699            summary.add_assign(
4700                &excerpt
4701                    .buffer
4702                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4703            );
4704
4705            if range.end > end_before_newline {
4706                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4707            }
4708
4709            cursor.next(&());
4710        }
4711
4712        if range.end > *cursor.start() {
4713            summary.add_assign(
4714                &cursor
4715                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4716                    .0,
4717            );
4718            if let Some(excerpt) = cursor.item() {
4719                range.end = cmp::max(*cursor.start(), range.end);
4720
4721                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4722                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4723                summary.add_assign(
4724                    &excerpt
4725                        .buffer
4726                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4727                );
4728            }
4729        }
4730
4731        summary
4732    }
4733
4734    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4735    where
4736        D: TextDimension + Ord + Sub<D, Output = D>,
4737    {
4738        self.summaries_for_anchors([anchor])[0]
4739    }
4740
4741    fn resolve_summary_for_anchor<D>(
4742        &self,
4743        anchor: &Anchor,
4744        excerpt_position: D,
4745        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4746    ) -> D
4747    where
4748        D: TextDimension + Ord + Sub<D, Output = D>,
4749    {
4750        loop {
4751            let transform_end_position = diff_transforms.end(&()).0.0;
4752            let at_transform_end =
4753                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4754            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4755                diff_transforms.next(&());
4756                continue;
4757            }
4758
4759            let mut position = diff_transforms.start().1.0;
4760            match diff_transforms.item() {
4761                Some(DiffTransform::DeletedHunk {
4762                    buffer_id,
4763                    base_text_byte_range,
4764                    ..
4765                }) => {
4766                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4767                        if let Some(base_text) =
4768                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4769                        {
4770                            if base_text.can_resolve(&diff_base_anchor) {
4771                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4772                                if base_text_offset >= base_text_byte_range.start
4773                                    && base_text_offset <= base_text_byte_range.end
4774                                {
4775                                    let position_in_hunk = base_text
4776                                        .text_summary_for_range::<D, _>(
4777                                            base_text_byte_range.start..base_text_offset,
4778                                        );
4779                                    position.add_assign(&position_in_hunk);
4780                                } else if at_transform_end {
4781                                    diff_transforms.next(&());
4782                                    continue;
4783                                }
4784                            }
4785                        }
4786                    }
4787                }
4788                _ => {
4789                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4790                        diff_transforms.next(&());
4791                        continue;
4792                    }
4793                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4794                    position.add_assign(&overshoot);
4795                }
4796            }
4797
4798            return position;
4799        }
4800    }
4801
4802    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4803        let mut cursor = self
4804            .excerpts
4805            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4806        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4807
4808        cursor.seek(&Some(locator), Bias::Left, &());
4809        if cursor.item().is_none() {
4810            cursor.next(&());
4811        }
4812
4813        let mut position = cursor.start().1;
4814        if let Some(excerpt) = cursor.item() {
4815            if excerpt.id == anchor.excerpt_id {
4816                let excerpt_buffer_start = excerpt
4817                    .buffer
4818                    .offset_for_anchor(&excerpt.range.context.start);
4819                let excerpt_buffer_end =
4820                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4821                let buffer_position = cmp::min(
4822                    excerpt_buffer_end,
4823                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4824                );
4825                if buffer_position > excerpt_buffer_start {
4826                    position.value += buffer_position - excerpt_buffer_start;
4827                }
4828            }
4829        }
4830        position
4831    }
4832
4833    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4834        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4835            excerpt_id = *replacement;
4836        }
4837        return excerpt_id;
4838    }
4839
4840    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4841    where
4842        D: TextDimension + Ord + Sub<D, Output = D>,
4843        I: 'a + IntoIterator<Item = &'a Anchor>,
4844    {
4845        let mut anchors = anchors.into_iter().peekable();
4846        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4847        let mut diff_transforms_cursor = self
4848            .diff_transforms
4849            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4850        diff_transforms_cursor.next(&());
4851
4852        let mut summaries = Vec::new();
4853        while let Some(anchor) = anchors.peek() {
4854            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4855            let excerpt_anchors = iter::from_fn(|| {
4856                let anchor = anchors.peek()?;
4857                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4858                    Some(anchors.next().unwrap())
4859                } else {
4860                    None
4861                }
4862            });
4863
4864            let locator = self.excerpt_locator_for_id(excerpt_id);
4865            cursor.seek_forward(locator, Bias::Left, &());
4866            if cursor.item().is_none() {
4867                cursor.next(&());
4868            }
4869
4870            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4871            if let Some(excerpt) = cursor.item() {
4872                if excerpt.id != excerpt_id {
4873                    let position = self.resolve_summary_for_anchor(
4874                        &Anchor::min(),
4875                        excerpt_start_position,
4876                        &mut diff_transforms_cursor,
4877                    );
4878                    summaries.extend(excerpt_anchors.map(|_| position));
4879                    continue;
4880                }
4881                let excerpt_buffer_start =
4882                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4883                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4884                for (buffer_summary, anchor) in excerpt
4885                    .buffer
4886                    .summaries_for_anchors_with_payload::<D, _, _>(
4887                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4888                    )
4889                {
4890                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4891                    let mut position = excerpt_start_position;
4892                    if summary > excerpt_buffer_start {
4893                        position.add_assign(&(summary - excerpt_buffer_start));
4894                    }
4895
4896                    if position > diff_transforms_cursor.start().0.0 {
4897                        diff_transforms_cursor.seek_forward(
4898                            &ExcerptDimension(position),
4899                            Bias::Left,
4900                            &(),
4901                        );
4902                    }
4903
4904                    summaries.push(self.resolve_summary_for_anchor(
4905                        anchor,
4906                        position,
4907                        &mut diff_transforms_cursor,
4908                    ));
4909                }
4910            } else {
4911                diff_transforms_cursor.seek_forward(
4912                    &ExcerptDimension(excerpt_start_position),
4913                    Bias::Left,
4914                    &(),
4915                );
4916                let position = self.resolve_summary_for_anchor(
4917                    &Anchor::max(),
4918                    excerpt_start_position,
4919                    &mut diff_transforms_cursor,
4920                );
4921                summaries.extend(excerpt_anchors.map(|_| position));
4922            }
4923        }
4924
4925        summaries
4926    }
4927
4928    pub fn dimensions_from_points<'a, D>(
4929        &'a self,
4930        points: impl 'a + IntoIterator<Item = Point>,
4931    ) -> impl 'a + Iterator<Item = D>
4932    where
4933        D: TextDimension + Sub<D, Output = D>,
4934    {
4935        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4936        cursor.seek(&DimensionPair {
4937            key: Point::default(),
4938            value: None,
4939        });
4940        let mut points = points.into_iter();
4941        iter::from_fn(move || {
4942            let point = points.next()?;
4943
4944            cursor.seek_forward(&DimensionPair {
4945                key: point,
4946                value: None,
4947            });
4948
4949            if let Some(region) = cursor.region() {
4950                let overshoot = point - region.range.start.key;
4951                let buffer_point = region.buffer_range.start.key + overshoot;
4952                let mut position = region.range.start.value.unwrap();
4953                position.add_assign(
4954                    &region
4955                        .buffer
4956                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4957                );
4958                if point == region.range.end.key && region.has_trailing_newline {
4959                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4960                }
4961                return Some(position);
4962            } else {
4963                return Some(D::from_text_summary(&self.text_summary()));
4964            }
4965        })
4966    }
4967
4968    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4969    where
4970        I: 'a + IntoIterator<Item = &'a Anchor>,
4971    {
4972        let mut anchors = anchors.into_iter().enumerate().peekable();
4973        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4974        cursor.next(&());
4975
4976        let mut result = Vec::new();
4977
4978        while let Some((_, anchor)) = anchors.peek() {
4979            let old_excerpt_id = anchor.excerpt_id;
4980
4981            // Find the location where this anchor's excerpt should be.
4982            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
4983            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
4984
4985            if cursor.item().is_none() {
4986                cursor.next(&());
4987            }
4988
4989            let next_excerpt = cursor.item();
4990            let prev_excerpt = cursor.prev_item();
4991
4992            // Process all of the anchors for this excerpt.
4993            while let Some((_, anchor)) = anchors.peek() {
4994                if anchor.excerpt_id != old_excerpt_id {
4995                    break;
4996                }
4997                let (anchor_ix, anchor) = anchors.next().unwrap();
4998                let mut anchor = *anchor;
4999
5000                // Leave min and max anchors unchanged if invalid or
5001                // if the old excerpt still exists at this location
5002                let mut kept_position = next_excerpt
5003                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
5004                    || old_excerpt_id == ExcerptId::max()
5005                    || old_excerpt_id == ExcerptId::min();
5006
5007                // If the old excerpt no longer exists at this location, then attempt to
5008                // find an equivalent position for this anchor in an adjacent excerpt.
5009                if !kept_position {
5010                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5011                        if excerpt.contains(&anchor) {
5012                            anchor.excerpt_id = excerpt.id;
5013                            kept_position = true;
5014                            break;
5015                        }
5016                    }
5017                }
5018
5019                // If there's no adjacent excerpt that contains the anchor's position,
5020                // then report that the anchor has lost its position.
5021                if !kept_position {
5022                    anchor = if let Some(excerpt) = next_excerpt {
5023                        let mut text_anchor = excerpt
5024                            .range
5025                            .context
5026                            .start
5027                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5028                        if text_anchor
5029                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5030                            .is_gt()
5031                        {
5032                            text_anchor = excerpt.range.context.end;
5033                        }
5034                        Anchor {
5035                            buffer_id: Some(excerpt.buffer_id),
5036                            excerpt_id: excerpt.id,
5037                            text_anchor,
5038                            diff_base_anchor: None,
5039                        }
5040                    } else if let Some(excerpt) = prev_excerpt {
5041                        let mut text_anchor = excerpt
5042                            .range
5043                            .context
5044                            .end
5045                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5046                        if text_anchor
5047                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5048                            .is_lt()
5049                        {
5050                            text_anchor = excerpt.range.context.start;
5051                        }
5052                        Anchor {
5053                            buffer_id: Some(excerpt.buffer_id),
5054                            excerpt_id: excerpt.id,
5055                            text_anchor,
5056                            diff_base_anchor: None,
5057                        }
5058                    } else if anchor.text_anchor.bias == Bias::Left {
5059                        Anchor::min()
5060                    } else {
5061                        Anchor::max()
5062                    };
5063                }
5064
5065                result.push((anchor_ix, anchor, kept_position));
5066            }
5067        }
5068        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5069        result
5070    }
5071
5072    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5073        self.anchor_at(position, Bias::Left)
5074    }
5075
5076    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5077        self.anchor_at(position, Bias::Right)
5078    }
5079
5080    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5081        let offset = position.to_offset(self);
5082
5083        // Find the given position in the diff transforms. Determine the corresponding
5084        // offset in the excerpts, and whether the position is within a deleted hunk.
5085        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
5086        diff_transforms.seek(&offset, Bias::Right, &());
5087
5088        if offset == diff_transforms.start().0 && bias == Bias::Left {
5089            if let Some(prev_item) = diff_transforms.prev_item() {
5090                match prev_item {
5091                    DiffTransform::DeletedHunk { .. } => {
5092                        diff_transforms.prev(&());
5093                    }
5094                    _ => {}
5095                }
5096            }
5097        }
5098        let offset_in_transform = offset - diff_transforms.start().0;
5099        let mut excerpt_offset = diff_transforms.start().1;
5100        let mut diff_base_anchor = None;
5101        if let Some(DiffTransform::DeletedHunk {
5102            buffer_id,
5103            base_text_byte_range,
5104            has_trailing_newline,
5105            ..
5106        }) = diff_transforms.item()
5107        {
5108            let diff = self.diffs.get(buffer_id).expect("missing diff");
5109            if offset_in_transform > base_text_byte_range.len() {
5110                debug_assert!(*has_trailing_newline);
5111                bias = Bias::Right;
5112            } else {
5113                diff_base_anchor = Some(
5114                    diff.base_text()
5115                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5116                );
5117                bias = Bias::Left;
5118            }
5119        } else {
5120            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5121        };
5122
5123        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5124            return Anchor {
5125                buffer_id: Some(buffer_id),
5126                excerpt_id: *excerpt_id,
5127                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5128                diff_base_anchor,
5129            };
5130        }
5131
5132        let mut excerpts = self
5133            .excerpts
5134            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
5135        excerpts.seek(&excerpt_offset, Bias::Right, &());
5136        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5137            excerpts.prev(&());
5138        }
5139        if let Some(excerpt) = excerpts.item() {
5140            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5141            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
5142                overshoot -= 1;
5143                bias = Bias::Right;
5144            }
5145
5146            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5147            let text_anchor =
5148                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5149            Anchor {
5150                buffer_id: Some(excerpt.buffer_id),
5151                excerpt_id: excerpt.id,
5152                text_anchor,
5153                diff_base_anchor,
5154            }
5155        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5156            Anchor::min()
5157        } else {
5158            Anchor::max()
5159        }
5160    }
5161
5162    /// Returns an anchor for the given excerpt and text anchor,
5163    /// returns None if the excerpt_id is no longer valid.
5164    pub fn anchor_in_excerpt(
5165        &self,
5166        excerpt_id: ExcerptId,
5167        text_anchor: text::Anchor,
5168    ) -> Option<Anchor> {
5169        let locator = self.excerpt_locator_for_id(excerpt_id);
5170        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5171        cursor.seek(locator, Bias::Left, &());
5172        if let Some(excerpt) = cursor.item() {
5173            if excerpt.id == excerpt_id {
5174                let text_anchor = excerpt.clip_anchor(text_anchor);
5175                drop(cursor);
5176                return Some(Anchor {
5177                    buffer_id: Some(excerpt.buffer_id),
5178                    excerpt_id,
5179                    text_anchor,
5180                    diff_base_anchor: None,
5181                });
5182            }
5183        }
5184        None
5185    }
5186
5187    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5188        Some(self.excerpt(excerpt_id)?.range.context.clone())
5189    }
5190
5191    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5192        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5193            true
5194        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5195            excerpt.buffer.can_resolve(&anchor.text_anchor)
5196        } else {
5197            false
5198        }
5199    }
5200
5201    pub fn excerpts(
5202        &self,
5203    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5204        self.excerpts
5205            .iter()
5206            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5207    }
5208
5209    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
5210        let excerpts = self.excerpts.cursor(&());
5211        let diff_transforms = self.diff_transforms.cursor(&());
5212        MultiBufferCursor {
5213            excerpts,
5214            diff_transforms,
5215            diffs: &self.diffs,
5216            cached_region: None,
5217        }
5218    }
5219
5220    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5221        let start_locator = self.excerpt_locator_for_id(id);
5222        let mut excerpts = self
5223            .excerpts
5224            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5225        excerpts.seek(&Some(start_locator), Bias::Left, &());
5226        excerpts.prev(&());
5227
5228        let mut diff_transforms = self
5229            .diff_transforms
5230            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5231        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5232        if diff_transforms.end(&()).1 < excerpts.start().1 {
5233            diff_transforms.next(&());
5234        }
5235
5236        let excerpt = excerpts.item()?;
5237        Some(MultiBufferExcerpt {
5238            excerpt,
5239            offset: diff_transforms.start().0.0,
5240            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5241            excerpt_offset: excerpts.start().1.clone(),
5242            diff_transforms,
5243        })
5244    }
5245
5246    pub fn excerpt_boundaries_in_range<R, T>(
5247        &self,
5248        range: R,
5249    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5250    where
5251        R: RangeBounds<T>,
5252        T: ToOffset,
5253    {
5254        let start_offset;
5255        let start = match range.start_bound() {
5256            Bound::Included(start) => {
5257                start_offset = start.to_offset(self);
5258                Bound::Included(start_offset)
5259            }
5260            Bound::Excluded(_) => {
5261                panic!("not supported")
5262            }
5263            Bound::Unbounded => {
5264                start_offset = 0;
5265                Bound::Unbounded
5266            }
5267        };
5268        let end = match range.end_bound() {
5269            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5270            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5271            Bound::Unbounded => Bound::Unbounded,
5272        };
5273        let bounds = (start, end);
5274
5275        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5276        cursor.seek(&DimensionPair {
5277            key: start_offset,
5278            value: None,
5279        });
5280
5281        if cursor
5282            .region()
5283            .is_some_and(|region| bounds.contains(&region.range.start.key))
5284        {
5285            cursor.prev_excerpt();
5286        } else {
5287            cursor.seek_to_start_of_current_excerpt();
5288        }
5289        let mut prev_region = cursor.region();
5290
5291        cursor.next_excerpt();
5292
5293        iter::from_fn(move || {
5294            loop {
5295                if self.singleton {
5296                    return None;
5297                }
5298
5299                let next_region = cursor.region()?;
5300                cursor.next_excerpt();
5301                if !bounds.contains(&next_region.range.start.key) {
5302                    prev_region = Some(next_region);
5303                    continue;
5304                }
5305
5306                let next_region_start = next_region.range.start.value.unwrap();
5307                let next_region_end = if let Some(region) = cursor.region() {
5308                    region.range.start.value.unwrap()
5309                } else {
5310                    self.max_point()
5311                };
5312
5313                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5314                    id: region.excerpt.id,
5315                    buffer: region.excerpt.buffer.clone(),
5316                    buffer_id: region.excerpt.buffer_id,
5317                    range: region.excerpt.range.clone(),
5318                    end_row: MultiBufferRow(next_region_start.row),
5319                });
5320
5321                let next = ExcerptInfo {
5322                    id: next_region.excerpt.id,
5323                    buffer: next_region.excerpt.buffer.clone(),
5324                    buffer_id: next_region.excerpt.buffer_id,
5325                    range: next_region.excerpt.range.clone(),
5326                    end_row: if next_region.excerpt.has_trailing_newline {
5327                        MultiBufferRow(next_region_end.row - 1)
5328                    } else {
5329                        MultiBufferRow(next_region_end.row)
5330                    },
5331                };
5332
5333                let row = MultiBufferRow(next_region_start.row);
5334
5335                prev_region = Some(next_region);
5336
5337                return Some(ExcerptBoundary { row, prev, next });
5338            }
5339        })
5340    }
5341
5342    pub fn edit_count(&self) -> usize {
5343        self.edit_count
5344    }
5345
5346    pub fn non_text_state_update_count(&self) -> usize {
5347        self.non_text_state_update_count
5348    }
5349
5350    /// Returns the smallest enclosing bracket ranges containing the given range or
5351    /// None if no brackets contain range or the range is not contained in a single
5352    /// excerpt
5353    ///
5354    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5355    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5356        &self,
5357        range: Range<T>,
5358        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5359    ) -> Option<(Range<usize>, Range<usize>)> {
5360        let range = range.start.to_offset(self)..range.end.to_offset(self);
5361        let mut excerpt = self.excerpt_containing(range.clone())?;
5362        let buffer = excerpt.buffer();
5363        let excerpt_buffer_range = excerpt.buffer_range();
5364
5365        // Filter to ranges contained in the excerpt
5366        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5367            excerpt_buffer_range.contains(&open.start)
5368                && excerpt_buffer_range.contains(&close.end)
5369                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5370        };
5371
5372        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5373            excerpt.map_range_to_buffer(range),
5374            Some(&range_filter),
5375        )?;
5376
5377        Some((
5378            excerpt.map_range_from_buffer(open),
5379            excerpt.map_range_from_buffer(close),
5380        ))
5381    }
5382
5383    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5384    /// not contained in a single excerpt
5385    pub fn enclosing_bracket_ranges<T: ToOffset>(
5386        &self,
5387        range: Range<T>,
5388    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5389        let range = range.start.to_offset(self)..range.end.to_offset(self);
5390        let mut excerpt = self.excerpt_containing(range.clone())?;
5391
5392        Some(
5393            excerpt
5394                .buffer()
5395                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5396                .filter_map(move |pair| {
5397                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5398                        Some((
5399                            excerpt.map_range_from_buffer(pair.open_range),
5400                            excerpt.map_range_from_buffer(pair.close_range),
5401                        ))
5402                    } else {
5403                        None
5404                    }
5405                }),
5406        )
5407    }
5408
5409    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5410    /// not contained in a single excerpt
5411    pub fn text_object_ranges<T: ToOffset>(
5412        &self,
5413        range: Range<T>,
5414        options: TreeSitterOptions,
5415    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5416        let range = range.start.to_offset(self)..range.end.to_offset(self);
5417        self.excerpt_containing(range.clone())
5418            .map(|mut excerpt| {
5419                excerpt
5420                    .buffer()
5421                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5422                    .filter_map(move |(range, text_object)| {
5423                        if excerpt.contains_buffer_range(range.clone()) {
5424                            Some((excerpt.map_range_from_buffer(range), text_object))
5425                        } else {
5426                            None
5427                        }
5428                    })
5429            })
5430            .into_iter()
5431            .flatten()
5432    }
5433
5434    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5435    /// not contained in a single excerpt
5436    pub fn bracket_ranges<T: ToOffset>(
5437        &self,
5438        range: Range<T>,
5439    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5440        let range = range.start.to_offset(self)..range.end.to_offset(self);
5441        let mut excerpt = self.excerpt_containing(range.clone())?;
5442
5443        Some(
5444            excerpt
5445                .buffer()
5446                .bracket_ranges(excerpt.map_range_to_buffer(range))
5447                .filter_map(move |pair| {
5448                    let buffer_range = pair.open_range.start..pair.close_range.end;
5449                    if excerpt.contains_buffer_range(buffer_range) {
5450                        Some((
5451                            excerpt.map_range_from_buffer(pair.open_range),
5452                            excerpt.map_range_from_buffer(pair.close_range),
5453                        ))
5454                    } else {
5455                        None
5456                    }
5457                }),
5458        )
5459    }
5460
5461    pub fn redacted_ranges<'a, T: ToOffset>(
5462        &'a self,
5463        range: Range<T>,
5464        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5465    ) -> impl Iterator<Item = Range<usize>> + 'a {
5466        let range = range.start.to_offset(self)..range.end.to_offset(self);
5467        self.lift_buffer_metadata(range, move |buffer, range| {
5468            if redaction_enabled(buffer.file()) {
5469                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5470            } else {
5471                None
5472            }
5473        })
5474        .map(|(range, _, _)| range)
5475    }
5476
5477    pub fn runnable_ranges(
5478        &self,
5479        range: Range<Anchor>,
5480    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5481        let range = range.start.to_offset(self)..range.end.to_offset(self);
5482        self.lift_buffer_metadata(range, move |buffer, range| {
5483            Some(
5484                buffer
5485                    .runnable_ranges(range.clone())
5486                    .filter(move |runnable| {
5487                        runnable.run_range.start >= range.start
5488                            && runnable.run_range.end < range.end
5489                    })
5490                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5491            )
5492        })
5493        .map(|(run_range, runnable, _)| language::RunnableRange {
5494            run_range,
5495            ..runnable
5496        })
5497    }
5498
5499    pub fn line_indents(
5500        &self,
5501        start_row: MultiBufferRow,
5502        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5503    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5504        let max_point = self.max_point();
5505        let mut cursor = self.cursor::<Point>();
5506        cursor.seek(&Point::new(start_row.0, 0));
5507        iter::from_fn(move || {
5508            let mut region = cursor.region()?;
5509            while !buffer_filter(&region.excerpt.buffer) {
5510                cursor.next();
5511                region = cursor.region()?;
5512            }
5513            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5514            let buffer_start_row =
5515                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5516
5517            let buffer_end_row = if region.is_main_buffer
5518                && (region.has_trailing_newline || region.range.end == max_point)
5519            {
5520                region.buffer_range.end.row
5521            } else {
5522                region.buffer_range.end.row.saturating_sub(1)
5523            };
5524
5525            let line_indents = region
5526                .buffer
5527                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5528            cursor.next();
5529            return Some(line_indents.map(move |(buffer_row, indent)| {
5530                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5531                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5532            }));
5533        })
5534        .flatten()
5535    }
5536
5537    pub fn reversed_line_indents(
5538        &self,
5539        end_row: MultiBufferRow,
5540        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5541    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5542        let max_point = self.max_point();
5543        let mut cursor = self.cursor::<Point>();
5544        cursor.seek(&Point::new(end_row.0, 0));
5545        iter::from_fn(move || {
5546            let mut region = cursor.region()?;
5547            while !buffer_filter(&region.excerpt.buffer) {
5548                cursor.prev();
5549                region = cursor.region()?;
5550            }
5551
5552            let buffer_start_row = region.buffer_range.start.row;
5553            let buffer_end_row = if region.is_main_buffer
5554                && (region.has_trailing_newline || region.range.end == max_point)
5555            {
5556                region.buffer_range.end.row + 1
5557            } else {
5558                region.buffer_range.end.row
5559            };
5560
5561            let overshoot = end_row.0 - region.range.start.row;
5562            let buffer_end_row =
5563                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5564
5565            let line_indents = region
5566                .buffer
5567                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5568            cursor.prev();
5569            return Some(line_indents.map(move |(buffer_row, indent)| {
5570                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5571                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5572            }));
5573        })
5574        .flatten()
5575    }
5576
5577    pub async fn enclosing_indent(
5578        &self,
5579        mut target_row: MultiBufferRow,
5580    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5581        let max_row = MultiBufferRow(self.max_point().row);
5582        if target_row >= max_row {
5583            return None;
5584        }
5585
5586        let mut target_indent = self.line_indent_for_row(target_row);
5587
5588        // If the current row is at the start of an indented block, we want to return this
5589        // block as the enclosing indent.
5590        if !target_indent.is_line_empty() && target_row < max_row {
5591            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5592            if !next_line_indent.is_line_empty()
5593                && target_indent.raw_len() < next_line_indent.raw_len()
5594            {
5595                target_indent = next_line_indent;
5596                target_row.0 += 1;
5597            }
5598        }
5599
5600        const SEARCH_ROW_LIMIT: u32 = 25000;
5601        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5602        const YIELD_INTERVAL: u32 = 100;
5603
5604        let mut accessed_row_counter = 0;
5605
5606        // If there is a blank line at the current row, search for the next non indented lines
5607        if target_indent.is_line_empty() {
5608            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5609            let end =
5610                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5611
5612            let mut non_empty_line_above = None;
5613            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5614                if row < start {
5615                    break;
5616                }
5617                accessed_row_counter += 1;
5618                if accessed_row_counter == YIELD_INTERVAL {
5619                    accessed_row_counter = 0;
5620                    yield_now().await;
5621                }
5622                if !indent.is_line_empty() {
5623                    non_empty_line_above = Some((row, indent));
5624                    break;
5625                }
5626            }
5627
5628            let mut non_empty_line_below = None;
5629            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5630                if row > end {
5631                    break;
5632                }
5633                accessed_row_counter += 1;
5634                if accessed_row_counter == YIELD_INTERVAL {
5635                    accessed_row_counter = 0;
5636                    yield_now().await;
5637                }
5638                if !indent.is_line_empty() {
5639                    non_empty_line_below = Some((row, indent));
5640                    break;
5641                }
5642            }
5643
5644            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5645                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5646                    if above_indent.raw_len() >= below_indent.raw_len() {
5647                        (above_row, above_indent)
5648                    } else {
5649                        (below_row, below_indent)
5650                    }
5651                }
5652                (Some(above), None) => above,
5653                (None, Some(below)) => below,
5654                _ => return None,
5655            };
5656
5657            target_indent = indent;
5658            target_row = row;
5659        }
5660
5661        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5662        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5663
5664        let mut start_indent = None;
5665        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5666            if row < start {
5667                break;
5668            }
5669            accessed_row_counter += 1;
5670            if accessed_row_counter == YIELD_INTERVAL {
5671                accessed_row_counter = 0;
5672                yield_now().await;
5673            }
5674            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5675                start_indent = Some((row, indent));
5676                break;
5677            }
5678        }
5679        let (start_row, start_indent_size) = start_indent?;
5680
5681        let mut end_indent = (end, None);
5682        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5683            if row > end {
5684                break;
5685            }
5686            accessed_row_counter += 1;
5687            if accessed_row_counter == YIELD_INTERVAL {
5688                accessed_row_counter = 0;
5689                yield_now().await;
5690            }
5691            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5692                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5693                break;
5694            }
5695        }
5696        let (end_row, end_indent_size) = end_indent;
5697
5698        let indent = if let Some(end_indent_size) = end_indent_size {
5699            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5700                start_indent_size
5701            } else {
5702                end_indent_size
5703            }
5704        } else {
5705            start_indent_size
5706        };
5707
5708        Some((start_row..end_row, indent))
5709    }
5710
5711    pub fn indent_guides_in_range<T: ToPoint>(
5712        &self,
5713        range: Range<T>,
5714        ignore_disabled_for_language: bool,
5715        cx: &App,
5716    ) -> impl Iterator<Item = IndentGuide> {
5717        let range = range.start.to_point(self)..range.end.to_point(self);
5718        let start_row = MultiBufferRow(range.start.row);
5719        let end_row = MultiBufferRow(range.end.row);
5720
5721        let mut row_indents = self.line_indents(start_row, |buffer| {
5722            let settings =
5723                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5724            settings.indent_guides.enabled || ignore_disabled_for_language
5725        });
5726
5727        let mut result = Vec::new();
5728        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5729
5730        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5731            if first_row > end_row {
5732                break;
5733            }
5734            let current_depth = indent_stack.len() as u32;
5735
5736            let settings =
5737                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5738            let tab_size = settings.tab_size.get() as u32;
5739
5740            // When encountering empty, continue until found useful line indent
5741            // then add to the indent stack with the depth found
5742            let mut found_indent = false;
5743            let mut last_row = first_row;
5744            if line_indent.is_line_empty() {
5745                while !found_indent {
5746                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5747                        break;
5748                    };
5749                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5750                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5751                        break;
5752                    }
5753
5754                    if new_line_indent.is_line_empty() {
5755                        continue;
5756                    }
5757                    last_row = target_row.min(end_row);
5758                    line_indent = new_line_indent;
5759                    found_indent = true;
5760                    break;
5761                }
5762            } else {
5763                found_indent = true
5764            }
5765
5766            let depth = if found_indent {
5767                line_indent.len(tab_size) / tab_size
5768                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5769            } else {
5770                current_depth
5771            };
5772
5773            match depth.cmp(&current_depth) {
5774                cmp::Ordering::Less => {
5775                    for _ in 0..(current_depth - depth) {
5776                        let mut indent = indent_stack.pop().unwrap();
5777                        if last_row != first_row {
5778                            // In this case, we landed on an empty row, had to seek forward,
5779                            // and discovered that the indent we where on is ending.
5780                            // This means that the last display row must
5781                            // be on line that ends this indent range, so we
5782                            // should display the range up to the first non-empty line
5783                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5784                        }
5785
5786                        result.push(indent)
5787                    }
5788                }
5789                cmp::Ordering::Greater => {
5790                    for next_depth in current_depth..depth {
5791                        indent_stack.push(IndentGuide {
5792                            buffer_id: buffer.remote_id(),
5793                            start_row: first_row,
5794                            end_row: last_row,
5795                            depth: next_depth,
5796                            tab_size,
5797                            settings: settings.indent_guides,
5798                        });
5799                    }
5800                }
5801                _ => {}
5802            }
5803
5804            for indent in indent_stack.iter_mut() {
5805                indent.end_row = last_row;
5806            }
5807        }
5808
5809        result.extend(indent_stack);
5810        result.into_iter()
5811    }
5812
5813    pub fn trailing_excerpt_update_count(&self) -> usize {
5814        self.trailing_excerpt_update_count
5815    }
5816
5817    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5818        self.point_to_buffer_offset(point)
5819            .and_then(|(buffer, _)| buffer.file())
5820    }
5821
5822    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5823        self.point_to_buffer_offset(point)
5824            .and_then(|(buffer, offset)| buffer.language_at(offset))
5825    }
5826
5827    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5828        self.excerpts
5829            .first()
5830            .map(|excerpt| &excerpt.buffer)
5831            .map(|buffer| {
5832                language_settings(
5833                    buffer.language().map(|language| language.name()),
5834                    buffer.file(),
5835                    cx,
5836                )
5837            })
5838            .unwrap_or_else(move || self.language_settings_at(0, cx))
5839    }
5840
5841    pub fn language_settings_at<'a, T: ToOffset>(
5842        &'a self,
5843        point: T,
5844        cx: &'a App,
5845    ) -> Cow<'a, LanguageSettings> {
5846        let mut language = None;
5847        let mut file = None;
5848        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5849            language = buffer.language_at(offset);
5850            file = buffer.file();
5851        }
5852        language_settings(language.map(|l| l.name()), file, cx)
5853    }
5854
5855    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5856        self.point_to_buffer_offset(point)
5857            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5858    }
5859
5860    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5861        self.point_to_buffer_offset(point)
5862            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5863            .unwrap_or_default()
5864    }
5865
5866    pub fn language_indent_size_at<T: ToOffset>(
5867        &self,
5868        position: T,
5869        cx: &App,
5870    ) -> Option<IndentSize> {
5871        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5872        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5873    }
5874
5875    pub fn is_dirty(&self) -> bool {
5876        self.is_dirty
5877    }
5878
5879    pub fn has_deleted_file(&self) -> bool {
5880        self.has_deleted_file
5881    }
5882
5883    pub fn has_conflict(&self) -> bool {
5884        self.has_conflict
5885    }
5886
5887    pub fn has_diagnostics(&self) -> bool {
5888        self.excerpts
5889            .iter()
5890            .any(|excerpt| excerpt.buffer.has_diagnostics())
5891    }
5892
5893    pub fn diagnostic_group(
5894        &self,
5895        buffer_id: BufferId,
5896        group_id: usize,
5897    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5898        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5899            if buffer.remote_id() != buffer_id {
5900                return None;
5901            };
5902            Some(
5903                buffer
5904                    .diagnostic_group(group_id)
5905                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5906            )
5907        })
5908        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5909    }
5910
5911    pub fn diagnostics_in_range<'a, T>(
5912        &'a self,
5913        range: Range<T>,
5914    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5915    where
5916        T: 'a
5917            + text::ToOffset
5918            + text::FromAnchor
5919            + TextDimension
5920            + Ord
5921            + Sub<T, Output = T>
5922            + fmt::Debug,
5923    {
5924        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5925            Some(
5926                buffer
5927                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5928                    .map(|entry| (entry.range, entry.diagnostic)),
5929            )
5930        })
5931        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5932    }
5933
5934    pub fn syntax_ancestor<T: ToOffset>(
5935        &self,
5936        range: Range<T>,
5937    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5938        let range = range.start.to_offset(self)..range.end.to_offset(self);
5939        let mut excerpt = self.excerpt_containing(range.clone())?;
5940        let node = excerpt
5941            .buffer()
5942            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5943        let node_range = node.byte_range();
5944        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5945            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5946        } else {
5947            MultiOrSingleBufferOffsetRange::Single(node_range)
5948        };
5949        Some((node, range))
5950    }
5951
5952    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5953        let (excerpt_id, _, buffer) = self.as_singleton()?;
5954        let outline = buffer.outline(theme)?;
5955        Some(Outline::new(
5956            outline
5957                .items
5958                .into_iter()
5959                .flat_map(|item| {
5960                    Some(OutlineItem {
5961                        depth: item.depth,
5962                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5963                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5964                        text: item.text,
5965                        highlight_ranges: item.highlight_ranges,
5966                        name_ranges: item.name_ranges,
5967                        body_range: item.body_range.and_then(|body_range| {
5968                            Some(
5969                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5970                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5971                            )
5972                        }),
5973                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5974                            Some(
5975                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
5976                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
5977                            )
5978                        }),
5979                    })
5980                })
5981                .collect(),
5982        ))
5983    }
5984
5985    pub fn symbols_containing<T: ToOffset>(
5986        &self,
5987        offset: T,
5988        theme: Option<&SyntaxTheme>,
5989    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
5990        let anchor = self.anchor_before(offset);
5991        let excerpt_id = anchor.excerpt_id;
5992        let excerpt = self.excerpt(excerpt_id)?;
5993        Some((
5994            excerpt.buffer_id,
5995            excerpt
5996                .buffer
5997                .symbols_containing(anchor.text_anchor, theme)
5998                .into_iter()
5999                .flatten()
6000                .flat_map(|item| {
6001                    Some(OutlineItem {
6002                        depth: item.depth,
6003                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6004                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6005                        text: item.text,
6006                        highlight_ranges: item.highlight_ranges,
6007                        name_ranges: item.name_ranges,
6008                        body_range: item.body_range.and_then(|body_range| {
6009                            Some(
6010                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6011                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6012                            )
6013                        }),
6014                        annotation_range: item.annotation_range.and_then(|body_range| {
6015                            Some(
6016                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6017                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6018                            )
6019                        }),
6020                    })
6021                })
6022                .collect(),
6023        ))
6024    }
6025
6026    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6027        if id == ExcerptId::min() {
6028            Locator::min_ref()
6029        } else if id == ExcerptId::max() {
6030            Locator::max_ref()
6031        } else {
6032            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6033            cursor.seek(&id, Bias::Left, &());
6034            if let Some(entry) = cursor.item() {
6035                if entry.id == id {
6036                    return &entry.locator;
6037                }
6038            }
6039            panic!("invalid excerpt id {:?}", id)
6040        }
6041    }
6042
6043    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6044    fn excerpt_locators_for_ids(
6045        &self,
6046        ids: impl IntoIterator<Item = ExcerptId>,
6047    ) -> SmallVec<[Locator; 1]> {
6048        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6049        sorted_ids.sort_unstable();
6050        let mut locators = SmallVec::new();
6051
6052        while sorted_ids.last() == Some(&ExcerptId::max()) {
6053            sorted_ids.pop();
6054            if let Some(mapping) = self.excerpt_ids.last() {
6055                locators.push(mapping.locator.clone());
6056            }
6057        }
6058
6059        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6060        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6061            sorted_ids.next();
6062            if let Some(mapping) = self.excerpt_ids.first() {
6063                locators.push(mapping.locator.clone());
6064            }
6065        }
6066
6067        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6068        for id in sorted_ids {
6069            if cursor.seek_forward(&id, Bias::Left, &()) {
6070                locators.push(cursor.item().unwrap().locator.clone());
6071            } else {
6072                panic!("invalid excerpt id {:?}", id);
6073            }
6074        }
6075
6076        locators.sort_unstable();
6077        locators
6078    }
6079
6080    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6081        Some(self.excerpt(excerpt_id)?.buffer_id)
6082    }
6083
6084    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6085        Some(&self.excerpt(excerpt_id)?.buffer)
6086    }
6087
6088    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6089        let mut cursor = self
6090            .excerpts
6091            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
6092        let locator = self.excerpt_locator_for_id(excerpt_id);
6093        if cursor.seek(&Some(locator), Bias::Left, &()) {
6094            let start = cursor.start().1.clone();
6095            let end = cursor.end(&()).1;
6096            let mut diff_transforms = self
6097                .diff_transforms
6098                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
6099            diff_transforms.seek(&start, Bias::Left, &());
6100            let overshoot = start.0 - diff_transforms.start().0.0;
6101            let start = diff_transforms.start().1.0 + overshoot;
6102            diff_transforms.seek(&end, Bias::Right, &());
6103            let overshoot = end.0 - diff_transforms.start().0.0;
6104            let end = diff_transforms.start().1.0 + overshoot;
6105            Some(start..end)
6106        } else {
6107            None
6108        }
6109    }
6110
6111    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6112        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6113        let locator = self.excerpt_locator_for_id(excerpt_id);
6114        if cursor.seek(&Some(locator), Bias::Left, &()) {
6115            if let Some(excerpt) = cursor.item() {
6116                return Some(excerpt.range.context.clone());
6117            }
6118        }
6119        None
6120    }
6121
6122    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6123        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6124        let locator = self.excerpt_locator_for_id(excerpt_id);
6125        cursor.seek(&Some(locator), Bias::Left, &());
6126        if let Some(excerpt) = cursor.item() {
6127            if excerpt.id == excerpt_id {
6128                return Some(excerpt);
6129            }
6130        }
6131        None
6132    }
6133
6134    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6135    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
6136        let range = range.start.to_offset(self)..range.end.to_offset(self);
6137        let mut cursor = self.cursor::<usize>();
6138        cursor.seek(&range.start);
6139
6140        let start_excerpt = cursor.excerpt()?;
6141        if range.end != range.start {
6142            cursor.seek_forward(&range.end);
6143            if cursor.excerpt()?.id != start_excerpt.id {
6144                return None;
6145            }
6146        }
6147
6148        cursor.seek_to_start_of_current_excerpt();
6149        let region = cursor.region()?;
6150        let offset = region.range.start;
6151        let buffer_offset = region.buffer_range.start;
6152        let excerpt_offset = cursor.excerpts.start().clone();
6153        Some(MultiBufferExcerpt {
6154            diff_transforms: cursor.diff_transforms,
6155            excerpt: start_excerpt,
6156            offset,
6157            buffer_offset,
6158            excerpt_offset,
6159        })
6160    }
6161
6162    pub fn selections_in_range<'a>(
6163        &'a self,
6164        range: &'a Range<Anchor>,
6165        include_local: bool,
6166    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6167        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6168        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6169        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6170        cursor.seek(start_locator, Bias::Left, &());
6171        cursor
6172            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6173            .flat_map(move |excerpt| {
6174                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6175                if excerpt.id == range.start.excerpt_id {
6176                    query_range.start = range.start.text_anchor;
6177                }
6178                if excerpt.id == range.end.excerpt_id {
6179                    query_range.end = range.end.text_anchor;
6180                }
6181
6182                excerpt
6183                    .buffer
6184                    .selections_in_range(query_range, include_local)
6185                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6186                        selections.map(move |selection| {
6187                            let mut start = Anchor {
6188                                buffer_id: Some(excerpt.buffer_id),
6189                                excerpt_id: excerpt.id,
6190                                text_anchor: selection.start,
6191                                diff_base_anchor: None,
6192                            };
6193                            let mut end = Anchor {
6194                                buffer_id: Some(excerpt.buffer_id),
6195                                excerpt_id: excerpt.id,
6196                                text_anchor: selection.end,
6197                                diff_base_anchor: None,
6198                            };
6199                            if range.start.cmp(&start, self).is_gt() {
6200                                start = range.start;
6201                            }
6202                            if range.end.cmp(&end, self).is_lt() {
6203                                end = range.end;
6204                            }
6205
6206                            (
6207                                replica_id,
6208                                line_mode,
6209                                cursor_shape,
6210                                Selection {
6211                                    id: selection.id,
6212                                    start,
6213                                    end,
6214                                    reversed: selection.reversed,
6215                                    goal: selection.goal,
6216                                },
6217                            )
6218                        })
6219                    })
6220            })
6221    }
6222
6223    pub fn show_headers(&self) -> bool {
6224        self.show_headers
6225    }
6226
6227    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6228        self.diffs.get(&buffer_id)
6229    }
6230}
6231
6232#[cfg(any(test, feature = "test-support"))]
6233impl MultiBufferSnapshot {
6234    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6235        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6236        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6237        start..end
6238    }
6239
6240    #[cfg(any(test, feature = "test-support"))]
6241    fn check_invariants(&self) {
6242        let excerpts = self.excerpts.items(&());
6243        let excerpt_ids = self.excerpt_ids.items(&());
6244
6245        for (ix, excerpt) in excerpts.iter().enumerate() {
6246            if ix == 0 {
6247                if excerpt.locator <= Locator::min() {
6248                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6249                }
6250            } else if excerpt.locator <= excerpts[ix - 1].locator {
6251                panic!("excerpts are out-of-order: {:?}", excerpts);
6252            }
6253        }
6254
6255        for (ix, entry) in excerpt_ids.iter().enumerate() {
6256            if ix == 0 {
6257                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6258                    panic!("invalid first excerpt id {:?}", entry.id);
6259                }
6260            } else if entry.id <= excerpt_ids[ix - 1].id {
6261                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6262            }
6263        }
6264
6265        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6266            panic!(
6267                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6268                self.excerpts.summary().text.len,
6269                self.diff_transforms.summary().input,
6270                self.diff_transforms.items(&()),
6271            );
6272        }
6273
6274        let mut prev_transform: Option<&DiffTransform> = None;
6275        for item in self.diff_transforms.iter() {
6276            if let DiffTransform::BufferContent {
6277                summary,
6278                inserted_hunk_info,
6279            } = item
6280            {
6281                if let Some(DiffTransform::BufferContent {
6282                    inserted_hunk_info: prev_inserted_hunk_info,
6283                    ..
6284                }) = prev_transform
6285                {
6286                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6287                        panic!(
6288                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6289                            self.diff_transforms.items(&())
6290                        );
6291                    }
6292                }
6293                if summary.len == 0 && !self.is_empty() {
6294                    panic!("empty buffer content transform");
6295                }
6296            }
6297            prev_transform = Some(item);
6298        }
6299    }
6300}
6301
6302impl<'a, D> MultiBufferCursor<'a, D>
6303where
6304    D: TextDimension + Ord + Sub<D, Output = D>,
6305{
6306    fn seek(&mut self, position: &D) {
6307        self.cached_region.take();
6308        self.diff_transforms
6309            .seek(&OutputDimension(*position), Bias::Right, &());
6310        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6311            self.diff_transforms.prev(&());
6312        }
6313
6314        let mut excerpt_position = self.diff_transforms.start().1.0;
6315        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6316            let overshoot = *position - self.diff_transforms.start().0.0;
6317            excerpt_position.add_assign(&overshoot);
6318        }
6319
6320        self.excerpts
6321            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6322        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6323            self.excerpts.prev(&());
6324        }
6325    }
6326
6327    fn seek_forward(&mut self, position: &D) {
6328        self.cached_region.take();
6329        self.diff_transforms
6330            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6331        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6332            self.diff_transforms.prev(&());
6333        }
6334
6335        let overshoot = *position - self.diff_transforms.start().0.0;
6336        let mut excerpt_position = self.diff_transforms.start().1.0;
6337        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6338            excerpt_position.add_assign(&overshoot);
6339        }
6340
6341        self.excerpts
6342            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6343        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6344            self.excerpts.prev(&());
6345        }
6346    }
6347
6348    fn next_excerpt(&mut self) {
6349        self.excerpts.next(&());
6350        self.seek_to_start_of_current_excerpt();
6351    }
6352
6353    fn prev_excerpt(&mut self) {
6354        self.excerpts.prev(&());
6355        self.seek_to_start_of_current_excerpt();
6356    }
6357
6358    fn seek_to_start_of_current_excerpt(&mut self) {
6359        self.cached_region.take();
6360        self.diff_transforms
6361            .seek(self.excerpts.start(), Bias::Left, &());
6362        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6363            && self.diff_transforms.start().1 < *self.excerpts.start()
6364            && self.diff_transforms.next_item().is_some()
6365        {
6366            self.diff_transforms.next(&());
6367        }
6368    }
6369
6370    fn next(&mut self) {
6371        self.cached_region.take();
6372        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6373            cmp::Ordering::Less => self.diff_transforms.next(&()),
6374            cmp::Ordering::Greater => self.excerpts.next(&()),
6375            cmp::Ordering::Equal => {
6376                self.diff_transforms.next(&());
6377                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6378                    || self.diff_transforms.item().is_none()
6379                {
6380                    self.excerpts.next(&());
6381                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6382                    self.diff_transforms.item()
6383                {
6384                    if self
6385                        .excerpts
6386                        .item()
6387                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6388                    {
6389                        self.excerpts.next(&());
6390                    }
6391                }
6392            }
6393        }
6394    }
6395
6396    fn prev(&mut self) {
6397        self.cached_region.take();
6398        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6399            cmp::Ordering::Less => self.excerpts.prev(&()),
6400            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6401            cmp::Ordering::Equal => {
6402                self.diff_transforms.prev(&());
6403                if self.diff_transforms.start().1 < *self.excerpts.start()
6404                    || self.diff_transforms.item().is_none()
6405                {
6406                    self.excerpts.prev(&());
6407                }
6408            }
6409        }
6410    }
6411
6412    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6413        if self.cached_region.is_none() {
6414            self.cached_region = self.build_region();
6415        }
6416        self.cached_region.clone()
6417    }
6418
6419    fn is_at_start_of_excerpt(&mut self) -> bool {
6420        if self.diff_transforms.start().1 > *self.excerpts.start() {
6421            return false;
6422        } else if self.diff_transforms.start().1 < *self.excerpts.start() {
6423            return true;
6424        }
6425
6426        self.diff_transforms.prev(&());
6427        let prev_transform = self.diff_transforms.item();
6428        self.diff_transforms.next(&());
6429
6430        prev_transform.map_or(true, |next_transform| {
6431            matches!(next_transform, DiffTransform::BufferContent { .. })
6432        })
6433    }
6434
6435    fn is_at_end_of_excerpt(&mut self) -> bool {
6436        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6437            return false;
6438        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6439            || self.diff_transforms.item().is_none()
6440        {
6441            return true;
6442        }
6443
6444        let next_transform = self.diff_transforms.next_item();
6445        next_transform.map_or(true, |next_transform| match next_transform {
6446            DiffTransform::BufferContent { .. } => true,
6447            DiffTransform::DeletedHunk { hunk_info, .. } => self
6448                .excerpts
6449                .item()
6450                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6451        })
6452    }
6453
6454    fn main_buffer_position(&self) -> Option<D> {
6455        let excerpt = self.excerpts.item()?;
6456        let buffer = &excerpt.buffer;
6457        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6458        let mut buffer_start = buffer_context_start;
6459        let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6460        buffer_start.add_assign(&overshoot);
6461        Some(buffer_start)
6462    }
6463
6464    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6465        let excerpt = self.excerpts.item()?;
6466        match self.diff_transforms.item()? {
6467            DiffTransform::DeletedHunk {
6468                buffer_id,
6469                base_text_byte_range,
6470                has_trailing_newline,
6471                hunk_info,
6472                ..
6473            } => {
6474                let diff = self.diffs.get(&buffer_id)?;
6475                let buffer = diff.base_text();
6476                let mut rope_cursor = buffer.as_rope().cursor(0);
6477                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6478                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6479                let mut buffer_end = buffer_start;
6480                buffer_end.add_assign(&buffer_range_len);
6481                let start = self.diff_transforms.start().0.0;
6482                let end = self.diff_transforms.end(&()).0.0;
6483                return Some(MultiBufferRegion {
6484                    buffer,
6485                    excerpt,
6486                    has_trailing_newline: *has_trailing_newline,
6487                    is_main_buffer: false,
6488                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6489                        hunk_info.hunk_secondary_status,
6490                    )),
6491                    buffer_range: buffer_start..buffer_end,
6492                    range: start..end,
6493                });
6494            }
6495            DiffTransform::BufferContent {
6496                inserted_hunk_info, ..
6497            } => {
6498                let buffer = &excerpt.buffer;
6499                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6500
6501                let mut start = self.diff_transforms.start().0.0;
6502                let mut buffer_start = buffer_context_start;
6503                if self.diff_transforms.start().1 < *self.excerpts.start() {
6504                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1.0;
6505                    start.add_assign(&overshoot);
6506                } else {
6507                    let overshoot = self.diff_transforms.start().1.0 - self.excerpts.start().0;
6508                    buffer_start.add_assign(&overshoot);
6509                }
6510
6511                let mut end;
6512                let mut buffer_end;
6513                let has_trailing_newline;
6514                if self.diff_transforms.end(&()).1.0 < self.excerpts.end(&()).0 {
6515                    let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6516                    end = self.diff_transforms.end(&()).0.0;
6517                    buffer_end = buffer_context_start;
6518                    buffer_end.add_assign(&overshoot);
6519                    has_trailing_newline = false;
6520                } else {
6521                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1.0;
6522                    end = self.diff_transforms.start().0.0;
6523                    end.add_assign(&overshoot);
6524                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6525                    has_trailing_newline = excerpt.has_trailing_newline;
6526                };
6527
6528                Some(MultiBufferRegion {
6529                    buffer,
6530                    excerpt,
6531                    has_trailing_newline,
6532                    is_main_buffer: true,
6533                    diff_hunk_status: inserted_hunk_info
6534                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6535                    buffer_range: buffer_start..buffer_end,
6536                    range: start..end,
6537                })
6538            }
6539        }
6540    }
6541
6542    fn excerpt(&self) -> Option<&'a Excerpt> {
6543        self.excerpts.item()
6544    }
6545}
6546
6547impl History {
6548    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6549        self.transaction_depth += 1;
6550        if self.transaction_depth == 1 {
6551            let id = self.next_transaction_id.tick();
6552            self.undo_stack.push(Transaction {
6553                id,
6554                buffer_transactions: Default::default(),
6555                first_edit_at: now,
6556                last_edit_at: now,
6557                suppress_grouping: false,
6558            });
6559            Some(id)
6560        } else {
6561            None
6562        }
6563    }
6564
6565    fn end_transaction(
6566        &mut self,
6567        now: Instant,
6568        buffer_transactions: HashMap<BufferId, TransactionId>,
6569    ) -> bool {
6570        assert_ne!(self.transaction_depth, 0);
6571        self.transaction_depth -= 1;
6572        if self.transaction_depth == 0 {
6573            if buffer_transactions.is_empty() {
6574                self.undo_stack.pop();
6575                false
6576            } else {
6577                self.redo_stack.clear();
6578                let transaction = self.undo_stack.last_mut().unwrap();
6579                transaction.last_edit_at = now;
6580                for (buffer_id, transaction_id) in buffer_transactions {
6581                    transaction
6582                        .buffer_transactions
6583                        .entry(buffer_id)
6584                        .or_insert(transaction_id);
6585                }
6586                true
6587            }
6588        } else {
6589            false
6590        }
6591    }
6592
6593    fn push_transaction<'a, T>(
6594        &mut self,
6595        buffer_transactions: T,
6596        now: Instant,
6597        cx: &Context<MultiBuffer>,
6598    ) where
6599        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6600    {
6601        assert_eq!(self.transaction_depth, 0);
6602        let transaction = Transaction {
6603            id: self.next_transaction_id.tick(),
6604            buffer_transactions: buffer_transactions
6605                .into_iter()
6606                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6607                .collect(),
6608            first_edit_at: now,
6609            last_edit_at: now,
6610            suppress_grouping: false,
6611        };
6612        if !transaction.buffer_transactions.is_empty() {
6613            self.undo_stack.push(transaction);
6614            self.redo_stack.clear();
6615        }
6616    }
6617
6618    fn finalize_last_transaction(&mut self) {
6619        if let Some(transaction) = self.undo_stack.last_mut() {
6620            transaction.suppress_grouping = true;
6621        }
6622    }
6623
6624    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6625        if let Some(ix) = self
6626            .undo_stack
6627            .iter()
6628            .rposition(|transaction| transaction.id == transaction_id)
6629        {
6630            Some(self.undo_stack.remove(ix))
6631        } else if let Some(ix) = self
6632            .redo_stack
6633            .iter()
6634            .rposition(|transaction| transaction.id == transaction_id)
6635        {
6636            Some(self.redo_stack.remove(ix))
6637        } else {
6638            None
6639        }
6640    }
6641
6642    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6643        self.undo_stack
6644            .iter()
6645            .find(|transaction| transaction.id == transaction_id)
6646            .or_else(|| {
6647                self.redo_stack
6648                    .iter()
6649                    .find(|transaction| transaction.id == transaction_id)
6650            })
6651    }
6652
6653    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6654        self.undo_stack
6655            .iter_mut()
6656            .find(|transaction| transaction.id == transaction_id)
6657            .or_else(|| {
6658                self.redo_stack
6659                    .iter_mut()
6660                    .find(|transaction| transaction.id == transaction_id)
6661            })
6662    }
6663
6664    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6665        assert_eq!(self.transaction_depth, 0);
6666        if let Some(transaction) = self.undo_stack.pop() {
6667            self.redo_stack.push(transaction);
6668            self.redo_stack.last_mut()
6669        } else {
6670            None
6671        }
6672    }
6673
6674    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6675        assert_eq!(self.transaction_depth, 0);
6676        if let Some(transaction) = self.redo_stack.pop() {
6677            self.undo_stack.push(transaction);
6678            self.undo_stack.last_mut()
6679        } else {
6680            None
6681        }
6682    }
6683
6684    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6685        let ix = self
6686            .undo_stack
6687            .iter()
6688            .rposition(|transaction| transaction.id == transaction_id)?;
6689        let transaction = self.undo_stack.remove(ix);
6690        self.redo_stack.push(transaction);
6691        self.redo_stack.last()
6692    }
6693
6694    fn group(&mut self) -> Option<TransactionId> {
6695        let mut count = 0;
6696        let mut transactions = self.undo_stack.iter();
6697        if let Some(mut transaction) = transactions.next_back() {
6698            while let Some(prev_transaction) = transactions.next_back() {
6699                if !prev_transaction.suppress_grouping
6700                    && transaction.first_edit_at - prev_transaction.last_edit_at
6701                        <= self.group_interval
6702                {
6703                    transaction = prev_transaction;
6704                    count += 1;
6705                } else {
6706                    break;
6707                }
6708            }
6709        }
6710        self.group_trailing(count)
6711    }
6712
6713    fn group_until(&mut self, transaction_id: TransactionId) {
6714        let mut count = 0;
6715        for transaction in self.undo_stack.iter().rev() {
6716            if transaction.id == transaction_id {
6717                self.group_trailing(count);
6718                break;
6719            } else if transaction.suppress_grouping {
6720                break;
6721            } else {
6722                count += 1;
6723            }
6724        }
6725    }
6726
6727    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6728        let new_len = self.undo_stack.len() - n;
6729        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6730        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6731            if let Some(transaction) = transactions_to_merge.last() {
6732                last_transaction.last_edit_at = transaction.last_edit_at;
6733            }
6734            for to_merge in transactions_to_merge {
6735                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6736                    last_transaction
6737                        .buffer_transactions
6738                        .entry(*buffer_id)
6739                        .or_insert(*transaction_id);
6740                }
6741            }
6742        }
6743
6744        self.undo_stack.truncate(new_len);
6745        self.undo_stack.last().map(|t| t.id)
6746    }
6747}
6748
6749impl Excerpt {
6750    fn new(
6751        id: ExcerptId,
6752        locator: Locator,
6753        buffer_id: BufferId,
6754        buffer: BufferSnapshot,
6755        range: ExcerptRange<text::Anchor>,
6756        has_trailing_newline: bool,
6757    ) -> Self {
6758        Excerpt {
6759            id,
6760            locator,
6761            max_buffer_row: range.context.end.to_point(&buffer).row,
6762            text_summary: buffer
6763                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6764            buffer_id,
6765            buffer,
6766            range,
6767            has_trailing_newline,
6768        }
6769    }
6770
6771    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6772        let content_start = self.range.context.start.to_offset(&self.buffer);
6773        let chunks_start = content_start + range.start;
6774        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6775
6776        let footer_height = if self.has_trailing_newline
6777            && range.start <= self.text_summary.len
6778            && range.end > self.text_summary.len
6779        {
6780            1
6781        } else {
6782            0
6783        };
6784
6785        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6786
6787        ExcerptChunks {
6788            excerpt_id: self.id,
6789            content_chunks,
6790            footer_height,
6791        }
6792    }
6793
6794    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6795        let content_start = self.range.context.start.to_offset(&self.buffer);
6796        let chunks_start = content_start + range.start;
6797        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6798        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6799        excerpt_chunks.footer_height = if self.has_trailing_newline
6800            && range.start <= self.text_summary.len
6801            && range.end > self.text_summary.len
6802        {
6803            1
6804        } else {
6805            0
6806        };
6807    }
6808
6809    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6810        if text_anchor
6811            .cmp(&self.range.context.start, &self.buffer)
6812            .is_lt()
6813        {
6814            self.range.context.start
6815        } else if text_anchor
6816            .cmp(&self.range.context.end, &self.buffer)
6817            .is_gt()
6818        {
6819            self.range.context.end
6820        } else {
6821            text_anchor
6822        }
6823    }
6824
6825    fn contains(&self, anchor: &Anchor) -> bool {
6826        Some(self.buffer_id) == anchor.buffer_id
6827            && self
6828                .range
6829                .context
6830                .start
6831                .cmp(&anchor.text_anchor, &self.buffer)
6832                .is_le()
6833            && self
6834                .range
6835                .context
6836                .end
6837                .cmp(&anchor.text_anchor, &self.buffer)
6838                .is_ge()
6839    }
6840
6841    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6842    fn buffer_start_offset(&self) -> usize {
6843        self.range.context.start.to_offset(&self.buffer)
6844    }
6845
6846    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6847    fn buffer_end_offset(&self) -> usize {
6848        self.buffer_start_offset() + self.text_summary.len
6849    }
6850}
6851
6852impl<'a> MultiBufferExcerpt<'a> {
6853    pub fn id(&self) -> ExcerptId {
6854        self.excerpt.id
6855    }
6856
6857    pub fn buffer_id(&self) -> BufferId {
6858        self.excerpt.buffer_id
6859    }
6860
6861    pub fn start_anchor(&self) -> Anchor {
6862        Anchor {
6863            buffer_id: Some(self.excerpt.buffer_id),
6864            excerpt_id: self.excerpt.id,
6865            text_anchor: self.excerpt.range.context.start,
6866            diff_base_anchor: None,
6867        }
6868    }
6869
6870    pub fn end_anchor(&self) -> Anchor {
6871        Anchor {
6872            buffer_id: Some(self.excerpt.buffer_id),
6873            excerpt_id: self.excerpt.id,
6874            text_anchor: self.excerpt.range.context.end,
6875            diff_base_anchor: None,
6876        }
6877    }
6878
6879    pub fn buffer(&self) -> &'a BufferSnapshot {
6880        &self.excerpt.buffer
6881    }
6882
6883    pub fn buffer_range(&self) -> Range<usize> {
6884        self.buffer_offset
6885            ..self
6886                .excerpt
6887                .range
6888                .context
6889                .end
6890                .to_offset(&self.excerpt.buffer.text)
6891    }
6892
6893    pub fn start_offset(&self) -> usize {
6894        self.offset
6895    }
6896
6897    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6898    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6899        self.map_range_to_buffer(offset..offset).start
6900    }
6901
6902    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6903    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6904        self.diff_transforms
6905            .seek(&OutputDimension(range.start), Bias::Right, &());
6906        let start = self.map_offset_to_buffer_internal(range.start);
6907        let end = if range.end > range.start {
6908            self.diff_transforms
6909                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6910            self.map_offset_to_buffer_internal(range.end)
6911        } else {
6912            start
6913        };
6914        start..end
6915    }
6916
6917    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6918        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6919        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6920            excerpt_offset.0 += offset - self.diff_transforms.start().0.0;
6921        };
6922        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6923        self.buffer_offset + offset_in_excerpt
6924    }
6925
6926    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6927    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6928        self.map_range_from_buffer(buffer_offset..buffer_offset)
6929            .start
6930    }
6931
6932    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6933    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6934        if buffer_range.start < self.buffer_offset {
6935            log::warn!(
6936                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6937            );
6938            return buffer_range;
6939        }
6940        let overshoot = buffer_range.start - self.buffer_offset;
6941        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6942        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6943        if excerpt_offset.0 < self.diff_transforms.start().1.0 {
6944            log::warn!(
6945                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6946            );
6947            return buffer_range;
6948        }
6949        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
6950        let start = self.diff_transforms.start().0.0 + overshoot;
6951
6952        let end = if buffer_range.end > buffer_range.start {
6953            let overshoot = buffer_range.end - self.buffer_offset;
6954            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6955            self.diff_transforms
6956                .seek_forward(&excerpt_offset, Bias::Right, &());
6957            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
6958            self.diff_transforms.start().0.0 + overshoot
6959        } else {
6960            start
6961        };
6962
6963        start..end
6964    }
6965
6966    /// Returns true if the entirety of the given range is in the buffer's excerpt
6967    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6968        range.start >= self.excerpt.buffer_start_offset()
6969            && range.end <= self.excerpt.buffer_end_offset()
6970    }
6971
6972    pub fn max_buffer_row(&self) -> u32 {
6973        self.excerpt.max_buffer_row
6974    }
6975}
6976
6977impl ExcerptId {
6978    pub fn min() -> Self {
6979        Self(0)
6980    }
6981
6982    pub fn max() -> Self {
6983        Self(usize::MAX)
6984    }
6985
6986    pub fn to_proto(&self) -> u64 {
6987        self.0 as _
6988    }
6989
6990    pub fn from_proto(proto: u64) -> Self {
6991        Self(proto as _)
6992    }
6993
6994    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
6995        let a = snapshot.excerpt_locator_for_id(*self);
6996        let b = snapshot.excerpt_locator_for_id(*other);
6997        a.cmp(b).then_with(|| self.0.cmp(&other.0))
6998    }
6999}
7000
7001impl From<ExcerptId> for usize {
7002    fn from(val: ExcerptId) -> Self {
7003        val.0
7004    }
7005}
7006
7007impl fmt::Debug for Excerpt {
7008    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7009        f.debug_struct("Excerpt")
7010            .field("id", &self.id)
7011            .field("locator", &self.locator)
7012            .field("buffer_id", &self.buffer_id)
7013            .field("range", &self.range)
7014            .field("text_summary", &self.text_summary)
7015            .field("has_trailing_newline", &self.has_trailing_newline)
7016            .finish()
7017    }
7018}
7019
7020impl sum_tree::Item for Excerpt {
7021    type Summary = ExcerptSummary;
7022
7023    fn summary(&self, _cx: &()) -> Self::Summary {
7024        let mut text = self.text_summary;
7025        if self.has_trailing_newline {
7026            text += TextSummary::from("\n");
7027        }
7028        ExcerptSummary {
7029            excerpt_id: self.id,
7030            excerpt_locator: self.locator.clone(),
7031            widest_line_number: self.max_buffer_row,
7032            text,
7033        }
7034    }
7035}
7036
7037impl sum_tree::Item for ExcerptIdMapping {
7038    type Summary = ExcerptId;
7039
7040    fn summary(&self, _cx: &()) -> Self::Summary {
7041        self.id
7042    }
7043}
7044
7045impl sum_tree::KeyedItem for ExcerptIdMapping {
7046    type Key = ExcerptId;
7047
7048    fn key(&self) -> Self::Key {
7049        self.id
7050    }
7051}
7052
7053impl DiffTransform {
7054    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7055        match self {
7056            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7057            DiffTransform::BufferContent {
7058                inserted_hunk_info, ..
7059            } => *inserted_hunk_info,
7060        }
7061    }
7062}
7063
7064impl sum_tree::Item for DiffTransform {
7065    type Summary = DiffTransformSummary;
7066
7067    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7068        match self {
7069            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7070                input: *summary,
7071                output: *summary,
7072            },
7073            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7074                input: TextSummary::default(),
7075                output: *summary,
7076            },
7077        }
7078    }
7079}
7080
7081impl DiffTransformSummary {
7082    fn excerpt_len(&self) -> ExcerptOffset {
7083        ExcerptOffset::new(self.input.len)
7084    }
7085}
7086
7087impl sum_tree::Summary for DiffTransformSummary {
7088    type Context = ();
7089
7090    fn zero(_: &Self::Context) -> Self {
7091        DiffTransformSummary {
7092            input: TextSummary::default(),
7093            output: TextSummary::default(),
7094        }
7095    }
7096
7097    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7098        self.input += &summary.input;
7099        self.output += &summary.output;
7100    }
7101}
7102
7103impl sum_tree::Summary for ExcerptId {
7104    type Context = ();
7105
7106    fn zero(_cx: &()) -> Self {
7107        Default::default()
7108    }
7109
7110    fn add_summary(&mut self, other: &Self, _: &()) {
7111        *self = *other;
7112    }
7113}
7114
7115impl sum_tree::Summary for ExcerptSummary {
7116    type Context = ();
7117
7118    fn zero(_cx: &()) -> Self {
7119        Default::default()
7120    }
7121
7122    fn add_summary(&mut self, summary: &Self, _: &()) {
7123        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7124        self.excerpt_locator = summary.excerpt_locator.clone();
7125        self.text.add_summary(&summary.text, &());
7126        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7127    }
7128}
7129
7130impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7131    fn zero(_cx: &()) -> Self {
7132        Default::default()
7133    }
7134
7135    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7136        self.value += summary.text.len;
7137    }
7138}
7139
7140impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7141    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7142        Ord::cmp(&self.value, &cursor_location.text.len)
7143    }
7144}
7145
7146impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7147    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7148        Ord::cmp(&Some(self), cursor_location)
7149    }
7150}
7151
7152impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7153    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7154        Ord::cmp(self, &cursor_location.excerpt_locator)
7155    }
7156}
7157
7158impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7159    fn zero(_cx: &()) -> Self {
7160        Default::default()
7161    }
7162
7163    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7164        self.value += summary.text.lines;
7165    }
7166}
7167
7168impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7169    for ExcerptDimension<D>
7170{
7171    fn zero(_: &()) -> Self {
7172        ExcerptDimension(D::default())
7173    }
7174
7175    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7176        self.0.add_assign(&D::from_text_summary(&summary.text))
7177    }
7178}
7179
7180impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7181    fn zero(_cx: &()) -> Self {
7182        Default::default()
7183    }
7184
7185    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7186        *self = Some(&summary.excerpt_locator);
7187    }
7188}
7189
7190impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7191    fn zero(_cx: &()) -> Self {
7192        Default::default()
7193    }
7194
7195    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7196        *self = Some(summary.excerpt_id);
7197    }
7198}
7199
7200#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7201struct ExcerptDimension<T>(T);
7202
7203#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7204struct OutputDimension<T>(T);
7205
7206impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7207    fn zero(_: &()) -> Self {
7208        ExcerptOffset::new(0)
7209    }
7210
7211    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7212        self.value += summary.input.len;
7213    }
7214}
7215
7216impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7217    fn zero(_: &()) -> Self {
7218        ExcerptPoint::new(0, 0)
7219    }
7220
7221    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7222        self.value += summary.input.lines;
7223    }
7224}
7225
7226impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7227    for ExcerptDimension<D>
7228{
7229    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7230        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7231    }
7232}
7233
7234impl<D: TextDimension + Ord>
7235    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7236    for ExcerptDimension<D>
7237{
7238    fn cmp(
7239        &self,
7240        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7241        _: &(),
7242    ) -> cmp::Ordering {
7243        Ord::cmp(&self.0, &cursor_location.1.0)
7244    }
7245}
7246
7247impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7248    fn zero(_: &()) -> Self {
7249        ExcerptDimension(D::default())
7250    }
7251
7252    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7253        self.0.add_assign(&D::from_text_summary(&summary.input))
7254    }
7255}
7256
7257impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7258    fn zero(_: &()) -> Self {
7259        OutputDimension(D::default())
7260    }
7261
7262    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7263        self.0.add_assign(&D::from_text_summary(&summary.output))
7264    }
7265}
7266
7267impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7268    fn zero(_: &()) -> Self {
7269        TextSummary::default()
7270    }
7271
7272    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7273        *self += summary.output
7274    }
7275}
7276
7277impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7278    fn zero(_: &()) -> Self {
7279        0
7280    }
7281
7282    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7283        *self += summary.output.len
7284    }
7285}
7286
7287impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7288    fn zero(_: &()) -> Self {
7289        Point::new(0, 0)
7290    }
7291
7292    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7293        *self += summary.output.lines
7294    }
7295}
7296
7297impl MultiBufferRows<'_> {
7298    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7299        self.point = Point::new(row, 0);
7300        self.cursor.seek(&self.point);
7301    }
7302}
7303
7304impl Iterator for MultiBufferRows<'_> {
7305    type Item = RowInfo;
7306
7307    fn next(&mut self) -> Option<Self::Item> {
7308        if self.is_empty && self.point.row == 0 {
7309            self.point += Point::new(1, 0);
7310            return Some(RowInfo {
7311                buffer_id: None,
7312                buffer_row: Some(0),
7313                multibuffer_row: Some(MultiBufferRow(0)),
7314                diff_status: None,
7315                expand_info: None,
7316            });
7317        }
7318
7319        let mut region = self.cursor.region()?;
7320        while self.point >= region.range.end {
7321            self.cursor.next();
7322            if let Some(next_region) = self.cursor.region() {
7323                region = next_region;
7324            } else {
7325                if self.point == self.cursor.diff_transforms.end(&()).0.0 {
7326                    let multibuffer_row = MultiBufferRow(self.point.row);
7327                    let last_excerpt = self
7328                        .cursor
7329                        .excerpts
7330                        .item()
7331                        .or(self.cursor.excerpts.prev_item())?;
7332                    let last_row = last_excerpt
7333                        .range
7334                        .context
7335                        .end
7336                        .to_point(&last_excerpt.buffer)
7337                        .row;
7338
7339                    let first_row = last_excerpt
7340                        .range
7341                        .context
7342                        .start
7343                        .to_point(&last_excerpt.buffer)
7344                        .row;
7345
7346                    let expand_info = if self.is_singleton {
7347                        None
7348                    } else {
7349                        let needs_expand_up = first_row == last_row
7350                            && last_row > 0
7351                            && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7352                        let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7353
7354                        if needs_expand_up && needs_expand_down {
7355                            Some(ExpandExcerptDirection::UpAndDown)
7356                        } else if needs_expand_up {
7357                            Some(ExpandExcerptDirection::Up)
7358                        } else if needs_expand_down {
7359                            Some(ExpandExcerptDirection::Down)
7360                        } else {
7361                            None
7362                        }
7363                        .map(|direction| ExpandInfo {
7364                            direction,
7365                            excerpt_id: last_excerpt.id,
7366                        })
7367                    };
7368                    self.point += Point::new(1, 0);
7369                    return Some(RowInfo {
7370                        buffer_id: Some(last_excerpt.buffer_id),
7371                        buffer_row: Some(last_row),
7372                        multibuffer_row: Some(multibuffer_row),
7373                        diff_status: None,
7374                        expand_info,
7375                    });
7376                } else {
7377                    return None;
7378                }
7379            };
7380        }
7381
7382        let overshoot = self.point - region.range.start;
7383        let buffer_point = region.buffer_range.start + overshoot;
7384        let expand_info = if self.is_singleton {
7385            None
7386        } else {
7387            let needs_expand_up = self.point.row == region.range.start.row
7388                && self.cursor.is_at_start_of_excerpt()
7389                && buffer_point.row > 0;
7390            let needs_expand_down = (region.excerpt.has_trailing_newline
7391                && self.point.row + 1 == region.range.end.row
7392                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7393                && self.cursor.is_at_end_of_excerpt()
7394                && buffer_point.row < region.buffer.max_point().row;
7395
7396            if needs_expand_up && needs_expand_down {
7397                Some(ExpandExcerptDirection::UpAndDown)
7398            } else if needs_expand_up {
7399                Some(ExpandExcerptDirection::Up)
7400            } else if needs_expand_down {
7401                Some(ExpandExcerptDirection::Down)
7402            } else {
7403                None
7404            }
7405            .map(|direction| ExpandInfo {
7406                direction,
7407                excerpt_id: region.excerpt.id,
7408            })
7409        };
7410
7411        let result = Some(RowInfo {
7412            buffer_id: Some(region.buffer.remote_id()),
7413            buffer_row: Some(buffer_point.row),
7414            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7415            diff_status: region
7416                .diff_hunk_status
7417                .filter(|_| self.point < region.range.end),
7418            expand_info,
7419        });
7420        self.point += Point::new(1, 0);
7421        result
7422    }
7423}
7424
7425impl<'a> MultiBufferChunks<'a> {
7426    pub fn offset(&self) -> usize {
7427        self.range.start
7428    }
7429
7430    pub fn seek(&mut self, range: Range<usize>) {
7431        self.diff_transforms.seek(&range.end, Bias::Right, &());
7432        let mut excerpt_end = self.diff_transforms.start().1;
7433        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7434            let overshoot = range.end - self.diff_transforms.start().0;
7435            excerpt_end.value += overshoot;
7436        }
7437
7438        self.diff_transforms.seek(&range.start, Bias::Right, &());
7439        let mut excerpt_start = self.diff_transforms.start().1;
7440        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7441            let overshoot = range.start - self.diff_transforms.start().0;
7442            excerpt_start.value += overshoot;
7443        }
7444
7445        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7446        self.buffer_chunk.take();
7447        self.range = range;
7448    }
7449
7450    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7451        self.excerpt_offset_range = new_range.clone();
7452        self.excerpts.seek(&new_range.start, Bias::Right, &());
7453        if let Some(excerpt) = self.excerpts.item() {
7454            let excerpt_start = *self.excerpts.start();
7455            if let Some(excerpt_chunks) = self
7456                .excerpt_chunks
7457                .as_mut()
7458                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7459            {
7460                excerpt.seek_chunks(
7461                    excerpt_chunks,
7462                    (self.excerpt_offset_range.start - excerpt_start).value
7463                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7464                );
7465            } else {
7466                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7467                    (self.excerpt_offset_range.start - excerpt_start).value
7468                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7469                    self.language_aware,
7470                ));
7471            }
7472        } else {
7473            self.excerpt_chunks = None;
7474        }
7475    }
7476
7477    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7478        loop {
7479            if self.excerpt_offset_range.is_empty() {
7480                return None;
7481            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7482                self.excerpt_offset_range.start.value += chunk.text.len();
7483                return Some(chunk);
7484            } else {
7485                self.excerpts.next(&());
7486                let excerpt = self.excerpts.item()?;
7487                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7488                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7489                    self.language_aware,
7490                ));
7491            }
7492        }
7493    }
7494}
7495
7496impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7497    type Item = &'a str;
7498
7499    fn next(&mut self) -> Option<Self::Item> {
7500        let mut region = self.cursor.region()?;
7501        if self.offset == region.range.start {
7502            self.cursor.prev();
7503            region = self.cursor.region()?;
7504            let start_overshoot = self.start.saturating_sub(region.range.start);
7505            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7506                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7507            ));
7508        }
7509
7510        if self.offset == region.range.end && region.has_trailing_newline {
7511            self.offset -= 1;
7512            Some("\n")
7513        } else {
7514            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7515            self.offset -= chunk.len();
7516            Some(chunk)
7517        }
7518    }
7519}
7520
7521impl<'a> Iterator for MultiBufferChunks<'a> {
7522    type Item = Chunk<'a>;
7523
7524    fn next(&mut self) -> Option<Chunk<'a>> {
7525        if self.range.start >= self.range.end {
7526            return None;
7527        }
7528        if self.range.start == self.diff_transforms.end(&()).0 {
7529            self.diff_transforms.next(&());
7530        }
7531
7532        let diff_transform_start = self.diff_transforms.start().0;
7533        let diff_transform_end = self.diff_transforms.end(&()).0;
7534        debug_assert!(self.range.start < diff_transform_end);
7535
7536        let diff_transform = self.diff_transforms.item()?;
7537        match diff_transform {
7538            DiffTransform::BufferContent { .. } => {
7539                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7540                    chunk
7541                } else {
7542                    let chunk = self.next_excerpt_chunk().unwrap();
7543                    self.buffer_chunk.insert(chunk)
7544                };
7545
7546                let chunk_end = self.range.start + chunk.text.len();
7547                let diff_transform_end = diff_transform_end.min(self.range.end);
7548
7549                if diff_transform_end < chunk_end {
7550                    let (before, after) =
7551                        chunk.text.split_at(diff_transform_end - self.range.start);
7552                    self.range.start = diff_transform_end;
7553                    chunk.text = after;
7554                    Some(Chunk {
7555                        text: before,
7556                        ..chunk.clone()
7557                    })
7558                } else {
7559                    self.range.start = chunk_end;
7560                    self.buffer_chunk.take()
7561                }
7562            }
7563            DiffTransform::DeletedHunk {
7564                buffer_id,
7565                base_text_byte_range,
7566                has_trailing_newline,
7567                ..
7568            } => {
7569                let base_text_start =
7570                    base_text_byte_range.start + self.range.start - diff_transform_start;
7571                let base_text_end =
7572                    base_text_byte_range.start + self.range.end - diff_transform_start;
7573                let base_text_end = base_text_end.min(base_text_byte_range.end);
7574
7575                let mut chunks = if let Some((_, mut chunks)) = self
7576                    .diff_base_chunks
7577                    .take()
7578                    .filter(|(id, _)| id == buffer_id)
7579                {
7580                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7581                    {
7582                        chunks.seek(base_text_start..base_text_end);
7583                    }
7584                    chunks
7585                } else {
7586                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7587                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7588                };
7589
7590                let chunk = if let Some(chunk) = chunks.next() {
7591                    self.range.start += chunk.text.len();
7592                    self.diff_base_chunks = Some((*buffer_id, chunks));
7593                    chunk
7594                } else {
7595                    debug_assert!(has_trailing_newline);
7596                    self.range.start += "\n".len();
7597                    Chunk {
7598                        text: "\n",
7599                        ..Default::default()
7600                    }
7601                };
7602                Some(chunk)
7603            }
7604        }
7605    }
7606}
7607
7608impl MultiBufferBytes<'_> {
7609    fn consume(&mut self, len: usize) {
7610        self.range.start += len;
7611        self.chunk = &self.chunk[len..];
7612
7613        if !self.range.is_empty() && self.chunk.is_empty() {
7614            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7615                self.chunk = chunk;
7616            } else if self.has_trailing_newline {
7617                self.has_trailing_newline = false;
7618                self.chunk = b"\n";
7619            } else {
7620                self.cursor.next();
7621                if let Some(region) = self.cursor.region() {
7622                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7623                        region.buffer_range.start
7624                            ..(region.buffer_range.start + self.range.end - region.range.start)
7625                                .min(region.buffer_range.end),
7626                    );
7627                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7628                    self.excerpt_bytes = Some(excerpt_bytes);
7629                    self.has_trailing_newline =
7630                        region.has_trailing_newline && self.range.end >= region.range.end;
7631                    if self.chunk.is_empty() && self.has_trailing_newline {
7632                        self.has_trailing_newline = false;
7633                        self.chunk = b"\n";
7634                    }
7635                }
7636            }
7637        }
7638    }
7639}
7640
7641impl<'a> Iterator for MultiBufferBytes<'a> {
7642    type Item = &'a [u8];
7643
7644    fn next(&mut self) -> Option<Self::Item> {
7645        let chunk = self.chunk;
7646        if chunk.is_empty() {
7647            None
7648        } else {
7649            self.consume(chunk.len());
7650            Some(chunk)
7651        }
7652    }
7653}
7654
7655impl io::Read for MultiBufferBytes<'_> {
7656    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7657        let len = cmp::min(buf.len(), self.chunk.len());
7658        buf[..len].copy_from_slice(&self.chunk[..len]);
7659        if len > 0 {
7660            self.consume(len);
7661        }
7662        Ok(len)
7663    }
7664}
7665
7666impl io::Read for ReversedMultiBufferBytes<'_> {
7667    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7668        let len = cmp::min(buf.len(), self.chunk.len());
7669        buf[..len].copy_from_slice(&self.chunk[..len]);
7670        buf[..len].reverse();
7671        if len > 0 {
7672            self.range.end -= len;
7673            self.chunk = &self.chunk[..self.chunk.len() - len];
7674            if !self.range.is_empty() && self.chunk.is_empty() {
7675                if let Some(chunk) = self.chunks.next() {
7676                    self.chunk = chunk.as_bytes();
7677                }
7678            }
7679        }
7680        Ok(len)
7681    }
7682}
7683
7684impl<'a> Iterator for ExcerptChunks<'a> {
7685    type Item = Chunk<'a>;
7686
7687    fn next(&mut self) -> Option<Self::Item> {
7688        if let Some(chunk) = self.content_chunks.next() {
7689            return Some(chunk);
7690        }
7691
7692        if self.footer_height > 0 {
7693            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7694            self.footer_height = 0;
7695            return Some(Chunk {
7696                text,
7697                ..Default::default()
7698            });
7699        }
7700
7701        None
7702    }
7703}
7704
7705impl ToOffset for Point {
7706    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7707        snapshot.point_to_offset(*self)
7708    }
7709}
7710
7711impl ToOffset for usize {
7712    #[track_caller]
7713    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7714        assert!(*self <= snapshot.len(), "offset is out of range");
7715        *self
7716    }
7717}
7718
7719impl ToOffset for OffsetUtf16 {
7720    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7721        snapshot.offset_utf16_to_offset(*self)
7722    }
7723}
7724
7725impl ToOffset for PointUtf16 {
7726    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7727        snapshot.point_utf16_to_offset(*self)
7728    }
7729}
7730
7731impl ToOffsetUtf16 for OffsetUtf16 {
7732    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7733        *self
7734    }
7735}
7736
7737impl ToOffsetUtf16 for usize {
7738    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7739        snapshot.offset_to_offset_utf16(*self)
7740    }
7741}
7742
7743impl ToPoint for usize {
7744    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7745        snapshot.offset_to_point(*self)
7746    }
7747}
7748
7749impl ToPoint for Point {
7750    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7751        *self
7752    }
7753}
7754
7755impl ToPointUtf16 for usize {
7756    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7757        snapshot.offset_to_point_utf16(*self)
7758    }
7759}
7760
7761impl ToPointUtf16 for Point {
7762    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7763        snapshot.point_to_point_utf16(*self)
7764    }
7765}
7766
7767impl ToPointUtf16 for PointUtf16 {
7768    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7769        *self
7770    }
7771}
7772
7773impl From<ExcerptId> for EntityId {
7774    fn from(id: ExcerptId) -> Self {
7775        EntityId::from(id.0 as u64)
7776    }
7777}
7778
7779pub fn build_excerpt_ranges<T>(
7780    buffer: &BufferSnapshot,
7781    ranges: &[Range<T>],
7782    context_line_count: u32,
7783) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7784where
7785    T: text::ToPoint,
7786{
7787    let max_point = buffer.max_point();
7788    let mut range_counts = Vec::new();
7789    let mut excerpt_ranges = Vec::new();
7790    let mut range_iter = ranges
7791        .iter()
7792        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7793        .peekable();
7794    while let Some(range) = range_iter.next() {
7795        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7796        let row = (range.end.row + context_line_count).min(max_point.row);
7797        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7798
7799        let mut ranges_in_excerpt = 1;
7800
7801        while let Some(next_range) = range_iter.peek() {
7802            if next_range.start.row <= excerpt_end.row + context_line_count {
7803                let row = (next_range.end.row + context_line_count).min(max_point.row);
7804                excerpt_end = Point::new(row, buffer.line_len(row));
7805
7806                ranges_in_excerpt += 1;
7807                range_iter.next();
7808            } else {
7809                break;
7810            }
7811        }
7812
7813        excerpt_ranges.push(ExcerptRange {
7814            context: excerpt_start..excerpt_end,
7815            primary: range,
7816        });
7817        range_counts.push(ranges_in_excerpt);
7818    }
7819
7820    (excerpt_ranges, range_counts)
7821}