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