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