multi_buffer.rs

   1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt};
   4use anyhow::{anyhow, Result};
   5use clock::ReplicaId;
   6use collections::{BTreeMap, Bound, HashMap, HashSet};
   7use futures::{channel::mpsc, SinkExt};
   8use git::diff::DiffHunk;
   9use gpui::{AppContext, EventEmitter, Model, ModelContext};
  10pub use language::Completion;
  11use language::{
  12    char_kind,
  13    language_settings::{language_settings, LanguageSettings},
  14    AutoindentMode, Buffer, BufferChunks, BufferSnapshot, Capability, CharKind, Chunk, CursorShape,
  15    DiagnosticEntry, File, IndentSize, Language, LanguageScope, OffsetRangeExt, OffsetUtf16,
  16    Outline, OutlineItem, Point, PointUtf16, Selection, TextDimension, ToOffset as _,
  17    ToOffsetUtf16 as _, ToPoint as _, ToPointUtf16 as _, TransactionId, Unclipped,
  18};
  19use std::{
  20    borrow::Cow,
  21    cell::{Ref, RefCell},
  22    cmp, fmt,
  23    future::Future,
  24    io,
  25    iter::{self, FromIterator},
  26    mem,
  27    ops::{Range, RangeBounds, Sub},
  28    str,
  29    sync::Arc,
  30    time::{Duration, Instant},
  31};
  32use sum_tree::{Bias, Cursor, SumTree};
  33use text::{
  34    locator::Locator,
  35    subscription::{Subscription, Topic},
  36    BufferId, Edit, TextSummary,
  37};
  38use theme::SyntaxTheme;
  39use util::post_inc;
  40
  41#[cfg(any(test, feature = "test-support"))]
  42use gpui::Context;
  43
  44const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  45
  46#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  47pub struct ExcerptId(usize);
  48
  49pub struct MultiBuffer {
  50    snapshot: RefCell<MultiBufferSnapshot>,
  51    buffers: RefCell<HashMap<BufferId, BufferState>>,
  52    next_excerpt_id: usize,
  53    subscriptions: Topic,
  54    singleton: bool,
  55    replica_id: ReplicaId,
  56    history: History,
  57    title: Option<String>,
  58    capability: Capability,
  59}
  60
  61#[derive(Clone, Debug, PartialEq, Eq)]
  62pub enum Event {
  63    ExcerptsAdded {
  64        buffer: Model<Buffer>,
  65        predecessor: ExcerptId,
  66        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  67    },
  68    ExcerptsRemoved {
  69        ids: Vec<ExcerptId>,
  70    },
  71    ExcerptsEdited {
  72        ids: Vec<ExcerptId>,
  73    },
  74    Edited {
  75        singleton_buffer_edited: bool,
  76    },
  77    TransactionUndone {
  78        transaction_id: TransactionId,
  79    },
  80    Reloaded,
  81    DiffBaseChanged,
  82    LanguageChanged,
  83    CapabilityChanged,
  84    Reparsed,
  85    Saved,
  86    FileHandleChanged,
  87    Closed,
  88    DirtyChanged,
  89    DiagnosticsUpdated,
  90}
  91
  92#[derive(Clone)]
  93struct History {
  94    next_transaction_id: TransactionId,
  95    undo_stack: Vec<Transaction>,
  96    redo_stack: Vec<Transaction>,
  97    transaction_depth: usize,
  98    group_interval: Duration,
  99}
 100
 101#[derive(Clone)]
 102struct Transaction {
 103    id: TransactionId,
 104    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 105    first_edit_at: Instant,
 106    last_edit_at: Instant,
 107    suppress_grouping: bool,
 108}
 109
 110pub trait ToOffset: 'static + fmt::Debug {
 111    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 112}
 113
 114pub trait ToOffsetUtf16: 'static + fmt::Debug {
 115    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 116}
 117
 118pub trait ToPoint: 'static + fmt::Debug {
 119    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 120}
 121
 122pub trait ToPointUtf16: 'static + fmt::Debug {
 123    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 124}
 125
 126struct BufferState {
 127    buffer: Model<Buffer>,
 128    last_version: clock::Global,
 129    last_parse_count: usize,
 130    last_selections_update_count: usize,
 131    last_diagnostics_update_count: usize,
 132    last_file_update_count: usize,
 133    last_git_diff_update_count: usize,
 134    excerpts: Vec<Locator>,
 135    _subscriptions: [gpui::Subscription; 2],
 136}
 137
 138#[derive(Clone, Default)]
 139pub struct MultiBufferSnapshot {
 140    singleton: bool,
 141    excerpts: SumTree<Excerpt>,
 142    excerpt_ids: SumTree<ExcerptIdMapping>,
 143    parse_count: usize,
 144    diagnostics_update_count: usize,
 145    trailing_excerpt_update_count: usize,
 146    git_diff_update_count: usize,
 147    edit_count: usize,
 148    is_dirty: bool,
 149    has_conflict: bool,
 150}
 151
 152pub struct ExcerptBoundary {
 153    pub id: ExcerptId,
 154    pub row: u32,
 155    pub buffer: BufferSnapshot,
 156    pub range: ExcerptRange<text::Anchor>,
 157    pub starts_new_buffer: bool,
 158}
 159
 160#[derive(Clone)]
 161struct Excerpt {
 162    id: ExcerptId,
 163    locator: Locator,
 164    buffer_id: BufferId,
 165    buffer: BufferSnapshot,
 166    range: ExcerptRange<text::Anchor>,
 167    max_buffer_row: u32,
 168    text_summary: TextSummary,
 169    has_trailing_newline: bool,
 170}
 171
 172#[derive(Clone, Debug)]
 173struct ExcerptIdMapping {
 174    id: ExcerptId,
 175    locator: Locator,
 176}
 177
 178#[derive(Clone, Debug, Eq, PartialEq)]
 179pub struct ExcerptRange<T> {
 180    pub context: Range<T>,
 181    pub primary: Option<Range<T>>,
 182}
 183
 184#[derive(Clone, Debug, Default)]
 185struct ExcerptSummary {
 186    excerpt_id: ExcerptId,
 187    excerpt_locator: Locator,
 188    max_buffer_row: u32,
 189    text: TextSummary,
 190}
 191
 192#[derive(Clone)]
 193pub struct MultiBufferRows<'a> {
 194    buffer_row_range: Range<u32>,
 195    excerpts: Cursor<'a, Excerpt, Point>,
 196}
 197
 198pub struct MultiBufferChunks<'a> {
 199    range: Range<usize>,
 200    excerpts: Cursor<'a, Excerpt, usize>,
 201    excerpt_chunks: Option<ExcerptChunks<'a>>,
 202    language_aware: bool,
 203}
 204
 205pub struct MultiBufferBytes<'a> {
 206    range: Range<usize>,
 207    excerpts: Cursor<'a, Excerpt, usize>,
 208    excerpt_bytes: Option<ExcerptBytes<'a>>,
 209    chunk: &'a [u8],
 210}
 211
 212pub struct ReversedMultiBufferBytes<'a> {
 213    range: Range<usize>,
 214    excerpts: Cursor<'a, Excerpt, usize>,
 215    excerpt_bytes: Option<ExcerptBytes<'a>>,
 216    chunk: &'a [u8],
 217}
 218
 219struct ExcerptChunks<'a> {
 220    content_chunks: BufferChunks<'a>,
 221    footer_height: usize,
 222}
 223
 224struct ExcerptBytes<'a> {
 225    content_bytes: text::Bytes<'a>,
 226    footer_height: usize,
 227}
 228
 229impl MultiBuffer {
 230    pub fn new(replica_id: ReplicaId, capability: Capability) -> Self {
 231        Self {
 232            snapshot: Default::default(),
 233            buffers: Default::default(),
 234            next_excerpt_id: 1,
 235            subscriptions: Default::default(),
 236            singleton: false,
 237            capability,
 238            replica_id,
 239            history: History {
 240                next_transaction_id: Default::default(),
 241                undo_stack: Default::default(),
 242                redo_stack: Default::default(),
 243                transaction_depth: 0,
 244                group_interval: Duration::from_millis(300),
 245            },
 246            title: Default::default(),
 247        }
 248    }
 249
 250    pub fn clone(&self, new_cx: &mut ModelContext<Self>) -> Self {
 251        let mut buffers = HashMap::default();
 252        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 253            buffers.insert(
 254                *buffer_id,
 255                BufferState {
 256                    buffer: buffer_state.buffer.clone(),
 257                    last_version: buffer_state.last_version.clone(),
 258                    last_parse_count: buffer_state.last_parse_count,
 259                    last_selections_update_count: buffer_state.last_selections_update_count,
 260                    last_diagnostics_update_count: buffer_state.last_diagnostics_update_count,
 261                    last_file_update_count: buffer_state.last_file_update_count,
 262                    last_git_diff_update_count: buffer_state.last_git_diff_update_count,
 263                    excerpts: buffer_state.excerpts.clone(),
 264                    _subscriptions: [
 265                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 266                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 267                    ],
 268                },
 269            );
 270        }
 271        Self {
 272            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 273            buffers: RefCell::new(buffers),
 274            next_excerpt_id: 1,
 275            subscriptions: Default::default(),
 276            singleton: self.singleton,
 277            capability: self.capability,
 278            replica_id: self.replica_id,
 279            history: self.history.clone(),
 280            title: self.title.clone(),
 281        }
 282    }
 283
 284    pub fn with_title(mut self, title: String) -> Self {
 285        self.title = Some(title);
 286        self
 287    }
 288
 289    pub fn read_only(&self) -> bool {
 290        self.capability == Capability::ReadOnly
 291    }
 292
 293    pub fn singleton(buffer: Model<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 294        let mut this = Self::new(buffer.read(cx).replica_id(), buffer.read(cx).capability());
 295        this.singleton = true;
 296        this.push_excerpts(
 297            buffer,
 298            [ExcerptRange {
 299                context: text::Anchor::MIN..text::Anchor::MAX,
 300                primary: None,
 301            }],
 302            cx,
 303        );
 304        this.snapshot.borrow_mut().singleton = true;
 305        this
 306    }
 307
 308    pub fn replica_id(&self) -> ReplicaId {
 309        self.replica_id
 310    }
 311
 312    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 313        self.sync(cx);
 314        self.snapshot.borrow().clone()
 315    }
 316
 317    pub fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 318        self.sync(cx);
 319        self.snapshot.borrow()
 320    }
 321
 322    pub fn as_singleton(&self) -> Option<Model<Buffer>> {
 323        if self.singleton {
 324            return Some(
 325                self.buffers
 326                    .borrow()
 327                    .values()
 328                    .next()
 329                    .unwrap()
 330                    .buffer
 331                    .clone(),
 332            );
 333        } else {
 334            None
 335        }
 336    }
 337
 338    pub fn is_singleton(&self) -> bool {
 339        self.singleton
 340    }
 341
 342    pub fn subscribe(&mut self) -> Subscription {
 343        self.subscriptions.subscribe()
 344    }
 345
 346    pub fn is_dirty(&self, cx: &AppContext) -> bool {
 347        self.read(cx).is_dirty()
 348    }
 349
 350    pub fn has_conflict(&self, cx: &AppContext) -> bool {
 351        self.read(cx).has_conflict()
 352    }
 353
 354    // The `is_empty` signature doesn't match what clippy expects
 355    #[allow(clippy::len_without_is_empty)]
 356    pub fn len(&self, cx: &AppContext) -> usize {
 357        self.read(cx).len()
 358    }
 359
 360    pub fn is_empty(&self, cx: &AppContext) -> bool {
 361        self.len(cx) != 0
 362    }
 363
 364    pub fn symbols_containing<T: ToOffset>(
 365        &self,
 366        offset: T,
 367        theme: Option<&SyntaxTheme>,
 368        cx: &AppContext,
 369    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 370        self.read(cx).symbols_containing(offset, theme)
 371    }
 372
 373    pub fn edit<I, S, T>(
 374        &mut self,
 375        edits: I,
 376        mut autoindent_mode: Option<AutoindentMode>,
 377        cx: &mut ModelContext<Self>,
 378    ) where
 379        I: IntoIterator<Item = (Range<S>, T)>,
 380        S: ToOffset,
 381        T: Into<Arc<str>>,
 382    {
 383        if self.buffers.borrow().is_empty() {
 384            return;
 385        }
 386
 387        let snapshot = self.read(cx);
 388        let edits = edits.into_iter().map(|(range, new_text)| {
 389            let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 390            if range.start > range.end {
 391                mem::swap(&mut range.start, &mut range.end);
 392            }
 393            (range, new_text)
 394        });
 395
 396        if let Some(buffer) = self.as_singleton() {
 397            return buffer.update(cx, |buffer, cx| {
 398                buffer.edit(edits, autoindent_mode, cx);
 399            });
 400        }
 401
 402        let original_indent_columns = match &mut autoindent_mode {
 403            Some(AutoindentMode::Block {
 404                original_indent_columns,
 405            }) => mem::take(original_indent_columns),
 406            _ => Default::default(),
 407        };
 408
 409        struct BufferEdit {
 410            range: Range<usize>,
 411            new_text: Arc<str>,
 412            is_insertion: bool,
 413            original_indent_column: u32,
 414        }
 415        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 416        let mut edited_excerpt_ids = Vec::new();
 417        let mut cursor = snapshot.excerpts.cursor::<usize>();
 418        for (ix, (range, new_text)) in edits.enumerate() {
 419            let new_text: Arc<str> = new_text.into();
 420            let original_indent_column = original_indent_columns.get(ix).copied().unwrap_or(0);
 421            cursor.seek(&range.start, Bias::Right, &());
 422            if cursor.item().is_none() && range.start == *cursor.start() {
 423                cursor.prev(&());
 424            }
 425            let start_excerpt = cursor.item().expect("start offset out of bounds");
 426            let start_overshoot = range.start - cursor.start();
 427            let buffer_start = start_excerpt
 428                .range
 429                .context
 430                .start
 431                .to_offset(&start_excerpt.buffer)
 432                + start_overshoot;
 433            edited_excerpt_ids.push(start_excerpt.id);
 434
 435            cursor.seek(&range.end, Bias::Right, &());
 436            if cursor.item().is_none() && range.end == *cursor.start() {
 437                cursor.prev(&());
 438            }
 439            let end_excerpt = cursor.item().expect("end offset out of bounds");
 440            let end_overshoot = range.end - cursor.start();
 441            let buffer_end = end_excerpt
 442                .range
 443                .context
 444                .start
 445                .to_offset(&end_excerpt.buffer)
 446                + end_overshoot;
 447
 448            if start_excerpt.id == end_excerpt.id {
 449                buffer_edits
 450                    .entry(start_excerpt.buffer_id)
 451                    .or_insert(Vec::new())
 452                    .push(BufferEdit {
 453                        range: buffer_start..buffer_end,
 454                        new_text,
 455                        is_insertion: true,
 456                        original_indent_column,
 457                    });
 458            } else {
 459                edited_excerpt_ids.push(end_excerpt.id);
 460                let start_excerpt_range = buffer_start
 461                    ..start_excerpt
 462                        .range
 463                        .context
 464                        .end
 465                        .to_offset(&start_excerpt.buffer);
 466                let end_excerpt_range = end_excerpt
 467                    .range
 468                    .context
 469                    .start
 470                    .to_offset(&end_excerpt.buffer)
 471                    ..buffer_end;
 472                buffer_edits
 473                    .entry(start_excerpt.buffer_id)
 474                    .or_insert(Vec::new())
 475                    .push(BufferEdit {
 476                        range: start_excerpt_range,
 477                        new_text: new_text.clone(),
 478                        is_insertion: true,
 479                        original_indent_column,
 480                    });
 481                buffer_edits
 482                    .entry(end_excerpt.buffer_id)
 483                    .or_insert(Vec::new())
 484                    .push(BufferEdit {
 485                        range: end_excerpt_range,
 486                        new_text: new_text.clone(),
 487                        is_insertion: false,
 488                        original_indent_column,
 489                    });
 490
 491                cursor.seek(&range.start, Bias::Right, &());
 492                cursor.next(&());
 493                while let Some(excerpt) = cursor.item() {
 494                    if excerpt.id == end_excerpt.id {
 495                        break;
 496                    }
 497                    buffer_edits
 498                        .entry(excerpt.buffer_id)
 499                        .or_insert(Vec::new())
 500                        .push(BufferEdit {
 501                            range: excerpt.range.context.to_offset(&excerpt.buffer),
 502                            new_text: new_text.clone(),
 503                            is_insertion: false,
 504                            original_indent_column,
 505                        });
 506                    edited_excerpt_ids.push(excerpt.id);
 507                    cursor.next(&());
 508                }
 509            }
 510        }
 511
 512        drop(cursor);
 513        drop(snapshot);
 514        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 515        fn tail(
 516            this: &mut MultiBuffer,
 517            buffer_edits: HashMap<BufferId, Vec<BufferEdit>>,
 518            autoindent_mode: Option<AutoindentMode>,
 519            edited_excerpt_ids: Vec<ExcerptId>,
 520            cx: &mut ModelContext<MultiBuffer>,
 521        ) {
 522            for (buffer_id, mut edits) in buffer_edits {
 523                edits.sort_unstable_by_key(|edit| edit.range.start);
 524                this.buffers.borrow()[&buffer_id]
 525                    .buffer
 526                    .update(cx, |buffer, cx| {
 527                        let mut edits = edits.into_iter().peekable();
 528                        let mut insertions = Vec::new();
 529                        let mut original_indent_columns = Vec::new();
 530                        let mut deletions = Vec::new();
 531                        let empty_str: Arc<str> = "".into();
 532                        while let Some(BufferEdit {
 533                            mut range,
 534                            new_text,
 535                            mut is_insertion,
 536                            original_indent_column,
 537                        }) = edits.next()
 538                        {
 539                            while let Some(BufferEdit {
 540                                range: next_range,
 541                                is_insertion: next_is_insertion,
 542                                ..
 543                            }) = edits.peek()
 544                            {
 545                                if range.end >= next_range.start {
 546                                    range.end = cmp::max(next_range.end, range.end);
 547                                    is_insertion |= *next_is_insertion;
 548                                    edits.next();
 549                                } else {
 550                                    break;
 551                                }
 552                            }
 553
 554                            if is_insertion {
 555                                original_indent_columns.push(original_indent_column);
 556                                insertions.push((
 557                                    buffer.anchor_before(range.start)
 558                                        ..buffer.anchor_before(range.end),
 559                                    new_text.clone(),
 560                                ));
 561                            } else if !range.is_empty() {
 562                                deletions.push((
 563                                    buffer.anchor_before(range.start)
 564                                        ..buffer.anchor_before(range.end),
 565                                    empty_str.clone(),
 566                                ));
 567                            }
 568                        }
 569
 570                        let deletion_autoindent_mode =
 571                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 572                                Some(AutoindentMode::Block {
 573                                    original_indent_columns: Default::default(),
 574                                })
 575                            } else {
 576                                None
 577                            };
 578                        let insertion_autoindent_mode =
 579                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 580                                Some(AutoindentMode::Block {
 581                                    original_indent_columns,
 582                                })
 583                            } else {
 584                                None
 585                            };
 586
 587                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 588                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 589                    })
 590            }
 591
 592            cx.emit(Event::ExcerptsEdited {
 593                ids: edited_excerpt_ids,
 594            });
 595        }
 596        tail(self, buffer_edits, autoindent_mode, edited_excerpt_ids, cx);
 597    }
 598
 599    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 600        self.start_transaction_at(Instant::now(), cx)
 601    }
 602
 603    pub fn start_transaction_at(
 604        &mut self,
 605        now: Instant,
 606        cx: &mut ModelContext<Self>,
 607    ) -> Option<TransactionId> {
 608        if let Some(buffer) = self.as_singleton() {
 609            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 610        }
 611
 612        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 613            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 614        }
 615        self.history.start_transaction(now)
 616    }
 617
 618    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 619        self.end_transaction_at(Instant::now(), cx)
 620    }
 621
 622    pub fn end_transaction_at(
 623        &mut self,
 624        now: Instant,
 625        cx: &mut ModelContext<Self>,
 626    ) -> Option<TransactionId> {
 627        if let Some(buffer) = self.as_singleton() {
 628            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 629        }
 630
 631        let mut buffer_transactions = HashMap::default();
 632        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 633            if let Some(transaction_id) =
 634                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 635            {
 636                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
 637            }
 638        }
 639
 640        if self.history.end_transaction(now, buffer_transactions) {
 641            let transaction_id = self.history.group().unwrap();
 642            Some(transaction_id)
 643        } else {
 644            None
 645        }
 646    }
 647
 648    pub fn merge_transactions(
 649        &mut self,
 650        transaction: TransactionId,
 651        destination: TransactionId,
 652        cx: &mut ModelContext<Self>,
 653    ) {
 654        if let Some(buffer) = self.as_singleton() {
 655            buffer.update(cx, |buffer, _| {
 656                buffer.merge_transactions(transaction, destination)
 657            });
 658        } else {
 659            if let Some(transaction) = self.history.forget(transaction) {
 660                if let Some(destination) = self.history.transaction_mut(destination) {
 661                    for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
 662                        if let Some(destination_buffer_transaction_id) =
 663                            destination.buffer_transactions.get(&buffer_id)
 664                        {
 665                            if let Some(state) = self.buffers.borrow().get(&buffer_id) {
 666                                state.buffer.update(cx, |buffer, _| {
 667                                    buffer.merge_transactions(
 668                                        buffer_transaction_id,
 669                                        *destination_buffer_transaction_id,
 670                                    )
 671                                });
 672                            }
 673                        } else {
 674                            destination
 675                                .buffer_transactions
 676                                .insert(buffer_id, buffer_transaction_id);
 677                        }
 678                    }
 679                }
 680            }
 681        }
 682    }
 683
 684    pub fn finalize_last_transaction(&mut self, cx: &mut ModelContext<Self>) {
 685        self.history.finalize_last_transaction();
 686        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 687            buffer.update(cx, |buffer, _| {
 688                buffer.finalize_last_transaction();
 689            });
 690        }
 691    }
 692
 693    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &mut ModelContext<Self>)
 694    where
 695        T: IntoIterator<Item = (&'a Model<Buffer>, &'a language::Transaction)>,
 696    {
 697        self.history
 698            .push_transaction(buffer_transactions, Instant::now(), cx);
 699        self.history.finalize_last_transaction();
 700    }
 701
 702    pub fn group_until_transaction(
 703        &mut self,
 704        transaction_id: TransactionId,
 705        cx: &mut ModelContext<Self>,
 706    ) {
 707        if let Some(buffer) = self.as_singleton() {
 708            buffer.update(cx, |buffer, _| {
 709                buffer.group_until_transaction(transaction_id)
 710            });
 711        } else {
 712            self.history.group_until(transaction_id);
 713        }
 714    }
 715
 716    pub fn set_active_selections(
 717        &mut self,
 718        selections: &[Selection<Anchor>],
 719        line_mode: bool,
 720        cursor_shape: CursorShape,
 721        cx: &mut ModelContext<Self>,
 722    ) {
 723        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
 724            Default::default();
 725        let snapshot = self.read(cx);
 726        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
 727        for selection in selections {
 728            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
 729            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
 730
 731            cursor.seek(&Some(start_locator), Bias::Left, &());
 732            while let Some(excerpt) = cursor.item() {
 733                if excerpt.locator > *end_locator {
 734                    break;
 735                }
 736
 737                let mut start = excerpt.range.context.start;
 738                let mut end = excerpt.range.context.end;
 739                if excerpt.id == selection.start.excerpt_id {
 740                    start = selection.start.text_anchor;
 741                }
 742                if excerpt.id == selection.end.excerpt_id {
 743                    end = selection.end.text_anchor;
 744                }
 745                selections_by_buffer
 746                    .entry(excerpt.buffer_id)
 747                    .or_default()
 748                    .push(Selection {
 749                        id: selection.id,
 750                        start,
 751                        end,
 752                        reversed: selection.reversed,
 753                        goal: selection.goal,
 754                    });
 755
 756                cursor.next(&());
 757            }
 758        }
 759
 760        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 761            if !selections_by_buffer.contains_key(buffer_id) {
 762                buffer_state
 763                    .buffer
 764                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 765            }
 766        }
 767
 768        for (buffer_id, mut selections) in selections_by_buffer {
 769            self.buffers.borrow()[&buffer_id]
 770                .buffer
 771                .update(cx, |buffer, cx| {
 772                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
 773                    let mut selections = selections.into_iter().peekable();
 774                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 775                        let mut selection = selections.next()?;
 776                        while let Some(next_selection) = selections.peek() {
 777                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
 778                                let next_selection = selections.next().unwrap();
 779                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
 780                                    selection.end = next_selection.end;
 781                                }
 782                            } else {
 783                                break;
 784                            }
 785                        }
 786                        Some(selection)
 787                    }));
 788                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
 789                });
 790        }
 791    }
 792
 793    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
 794        for buffer in self.buffers.borrow().values() {
 795            buffer
 796                .buffer
 797                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 798        }
 799    }
 800
 801    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 802        let mut transaction_id = None;
 803        if let Some(buffer) = self.as_singleton() {
 804            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
 805        } else {
 806            while let Some(transaction) = self.history.pop_undo() {
 807                let mut undone = false;
 808                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 809                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
 810                        undone |= buffer.update(cx, |buffer, cx| {
 811                            let undo_to = *buffer_transaction_id;
 812                            if let Some(entry) = buffer.peek_undo_stack() {
 813                                *buffer_transaction_id = entry.transaction_id();
 814                            }
 815                            buffer.undo_to_transaction(undo_to, cx)
 816                        });
 817                    }
 818                }
 819
 820                if undone {
 821                    transaction_id = Some(transaction.id);
 822                    break;
 823                }
 824            }
 825        }
 826
 827        if let Some(transaction_id) = transaction_id {
 828            cx.emit(Event::TransactionUndone { transaction_id });
 829        }
 830
 831        transaction_id
 832    }
 833
 834    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 835        if let Some(buffer) = self.as_singleton() {
 836            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
 837        }
 838
 839        while let Some(transaction) = self.history.pop_redo() {
 840            let mut redone = false;
 841            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 842                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
 843                    redone |= buffer.update(cx, |buffer, cx| {
 844                        let redo_to = *buffer_transaction_id;
 845                        if let Some(entry) = buffer.peek_redo_stack() {
 846                            *buffer_transaction_id = entry.transaction_id();
 847                        }
 848                        buffer.redo_to_transaction(redo_to, cx)
 849                    });
 850                }
 851            }
 852
 853            if redone {
 854                return Some(transaction.id);
 855            }
 856        }
 857
 858        None
 859    }
 860
 861    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut ModelContext<Self>) {
 862        if let Some(buffer) = self.as_singleton() {
 863            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
 864        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
 865            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
 866                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
 867                    buffer.update(cx, |buffer, cx| {
 868                        buffer.undo_transaction(*transaction_id, cx)
 869                    });
 870                }
 871            }
 872        }
 873    }
 874
 875    pub fn stream_excerpts_with_context_lines(
 876        &mut self,
 877        buffer: Model<Buffer>,
 878        ranges: Vec<Range<text::Anchor>>,
 879        context_line_count: u32,
 880        cx: &mut ModelContext<Self>,
 881    ) -> mpsc::Receiver<Range<Anchor>> {
 882        let (buffer_id, buffer_snapshot) =
 883            buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
 884
 885        let (mut tx, rx) = mpsc::channel(256);
 886        cx.spawn(move |this, mut cx| async move {
 887            let mut excerpt_ranges = Vec::new();
 888            let mut range_counts = Vec::new();
 889            cx.background_executor()
 890                .scoped(|scope| {
 891                    scope.spawn(async {
 892                        let (ranges, counts) =
 893                            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
 894                        excerpt_ranges = ranges;
 895                        range_counts = counts;
 896                    });
 897                })
 898                .await;
 899
 900            let mut ranges = ranges.into_iter();
 901            let mut range_counts = range_counts.into_iter();
 902            for excerpt_ranges in excerpt_ranges.chunks(100) {
 903                let excerpt_ids = match this.update(&mut cx, |this, cx| {
 904                    this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
 905                }) {
 906                    Ok(excerpt_ids) => excerpt_ids,
 907                    Err(_) => return,
 908                };
 909
 910                for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.by_ref())
 911                {
 912                    for range in ranges.by_ref().take(range_count) {
 913                        let start = Anchor {
 914                            buffer_id: Some(buffer_id),
 915                            excerpt_id: excerpt_id.clone(),
 916                            text_anchor: range.start,
 917                        };
 918                        let end = Anchor {
 919                            buffer_id: Some(buffer_id),
 920                            excerpt_id: excerpt_id.clone(),
 921                            text_anchor: range.end,
 922                        };
 923                        if tx.send(start..end).await.is_err() {
 924                            break;
 925                        }
 926                    }
 927                }
 928            }
 929        })
 930        .detach();
 931
 932        rx
 933    }
 934
 935    pub fn push_excerpts<O>(
 936        &mut self,
 937        buffer: Model<Buffer>,
 938        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
 939        cx: &mut ModelContext<Self>,
 940    ) -> Vec<ExcerptId>
 941    where
 942        O: text::ToOffset,
 943    {
 944        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
 945    }
 946
 947    pub fn push_excerpts_with_context_lines<O>(
 948        &mut self,
 949        buffer: Model<Buffer>,
 950        ranges: Vec<Range<O>>,
 951        context_line_count: u32,
 952        cx: &mut ModelContext<Self>,
 953    ) -> Vec<Range<Anchor>>
 954    where
 955        O: text::ToPoint + text::ToOffset,
 956    {
 957        let buffer_id = buffer.read(cx).remote_id();
 958        let buffer_snapshot = buffer.read(cx).snapshot();
 959        let (excerpt_ranges, range_counts) =
 960            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
 961
 962        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
 963
 964        let mut anchor_ranges = Vec::new();
 965        let mut ranges = ranges.into_iter();
 966        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
 967            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
 968                let start = Anchor {
 969                    buffer_id: Some(buffer_id),
 970                    excerpt_id: excerpt_id.clone(),
 971                    text_anchor: buffer_snapshot.anchor_after(range.start),
 972                };
 973                let end = Anchor {
 974                    buffer_id: Some(buffer_id),
 975                    excerpt_id: excerpt_id.clone(),
 976                    text_anchor: buffer_snapshot.anchor_after(range.end),
 977                };
 978                start..end
 979            }))
 980        }
 981        anchor_ranges
 982    }
 983
 984    pub fn insert_excerpts_after<O>(
 985        &mut self,
 986        prev_excerpt_id: ExcerptId,
 987        buffer: Model<Buffer>,
 988        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
 989        cx: &mut ModelContext<Self>,
 990    ) -> Vec<ExcerptId>
 991    where
 992        O: text::ToOffset,
 993    {
 994        let mut ids = Vec::new();
 995        let mut next_excerpt_id = self.next_excerpt_id;
 996        self.insert_excerpts_with_ids_after(
 997            prev_excerpt_id,
 998            buffer,
 999            ranges.into_iter().map(|range| {
1000                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1001                ids.push(id);
1002                (id, range)
1003            }),
1004            cx,
1005        );
1006        ids
1007    }
1008
1009    pub fn insert_excerpts_with_ids_after<O>(
1010        &mut self,
1011        prev_excerpt_id: ExcerptId,
1012        buffer: Model<Buffer>,
1013        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1014        cx: &mut ModelContext<Self>,
1015    ) where
1016        O: text::ToOffset,
1017    {
1018        assert_eq!(self.history.transaction_depth, 0);
1019        let mut ranges = ranges.into_iter().peekable();
1020        if ranges.peek().is_none() {
1021            return Default::default();
1022        }
1023
1024        self.sync(cx);
1025
1026        let buffer_id = buffer.read(cx).remote_id();
1027        let buffer_snapshot = buffer.read(cx).snapshot();
1028
1029        let mut buffers = self.buffers.borrow_mut();
1030        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
1031            last_version: buffer_snapshot.version().clone(),
1032            last_parse_count: buffer_snapshot.parse_count(),
1033            last_selections_update_count: buffer_snapshot.selections_update_count(),
1034            last_diagnostics_update_count: buffer_snapshot.diagnostics_update_count(),
1035            last_file_update_count: buffer_snapshot.file_update_count(),
1036            last_git_diff_update_count: buffer_snapshot.git_diff_update_count(),
1037            excerpts: Default::default(),
1038            _subscriptions: [
1039                cx.observe(&buffer, |_, _, cx| cx.notify()),
1040                cx.subscribe(&buffer, Self::on_buffer_event),
1041            ],
1042            buffer: buffer.clone(),
1043        });
1044
1045        let mut snapshot = self.snapshot.borrow_mut();
1046
1047        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1048        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1049        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
1050        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1051        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1052
1053        let edit_start = new_excerpts.summary().text.len;
1054        new_excerpts.update_last(
1055            |excerpt| {
1056                excerpt.has_trailing_newline = true;
1057            },
1058            &(),
1059        );
1060
1061        let next_locator = if let Some(excerpt) = cursor.item() {
1062            excerpt.locator.clone()
1063        } else {
1064            Locator::max()
1065        };
1066
1067        let mut excerpts = Vec::new();
1068        while let Some((id, range)) = ranges.next() {
1069            let locator = Locator::between(&prev_locator, &next_locator);
1070            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
1071                buffer_state.excerpts.insert(ix, locator.clone());
1072            }
1073            let range = ExcerptRange {
1074                context: buffer_snapshot.anchor_before(&range.context.start)
1075                    ..buffer_snapshot.anchor_after(&range.context.end),
1076                primary: range.primary.map(|primary| {
1077                    buffer_snapshot.anchor_before(&primary.start)
1078                        ..buffer_snapshot.anchor_after(&primary.end)
1079                }),
1080            };
1081            if id.0 >= self.next_excerpt_id {
1082                self.next_excerpt_id = id.0 + 1;
1083            }
1084            excerpts.push((id, range.clone()));
1085            let excerpt = Excerpt::new(
1086                id,
1087                locator.clone(),
1088                buffer_id,
1089                buffer_snapshot.clone(),
1090                range,
1091                ranges.peek().is_some() || cursor.item().is_some(),
1092            );
1093            new_excerpts.push(excerpt, &());
1094            prev_locator = locator.clone();
1095            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
1096        }
1097
1098        let edit_end = new_excerpts.summary().text.len;
1099
1100        let suffix = cursor.suffix(&());
1101        let changed_trailing_excerpt = suffix.is_empty();
1102        new_excerpts.append(suffix, &());
1103        drop(cursor);
1104        snapshot.excerpts = new_excerpts;
1105        snapshot.excerpt_ids = new_excerpt_ids;
1106        if changed_trailing_excerpt {
1107            snapshot.trailing_excerpt_update_count += 1;
1108        }
1109
1110        self.subscriptions.publish_mut([Edit {
1111            old: edit_start..edit_start,
1112            new: edit_start..edit_end,
1113        }]);
1114        cx.emit(Event::Edited {
1115            singleton_buffer_edited: false,
1116        });
1117        cx.emit(Event::ExcerptsAdded {
1118            buffer,
1119            predecessor: prev_excerpt_id,
1120            excerpts,
1121        });
1122        cx.notify();
1123    }
1124
1125    pub fn clear(&mut self, cx: &mut ModelContext<Self>) {
1126        self.sync(cx);
1127        let ids = self.excerpt_ids();
1128        self.buffers.borrow_mut().clear();
1129        let mut snapshot = self.snapshot.borrow_mut();
1130        let prev_len = snapshot.len();
1131        snapshot.excerpts = Default::default();
1132        snapshot.trailing_excerpt_update_count += 1;
1133        snapshot.is_dirty = false;
1134        snapshot.has_conflict = false;
1135
1136        self.subscriptions.publish_mut([Edit {
1137            old: 0..prev_len,
1138            new: 0..0,
1139        }]);
1140        cx.emit(Event::Edited {
1141            singleton_buffer_edited: false,
1142        });
1143        cx.emit(Event::ExcerptsRemoved { ids });
1144        cx.notify();
1145    }
1146
1147    pub fn excerpts_for_buffer(
1148        &self,
1149        buffer: &Model<Buffer>,
1150        cx: &AppContext,
1151    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
1152        let mut excerpts = Vec::new();
1153        let snapshot = self.read(cx);
1154        let buffers = self.buffers.borrow();
1155        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
1156        for locator in buffers
1157            .get(&buffer.read(cx).remote_id())
1158            .map(|state| &state.excerpts)
1159            .into_iter()
1160            .flatten()
1161        {
1162            cursor.seek_forward(&Some(locator), Bias::Left, &());
1163            if let Some(excerpt) = cursor.item() {
1164                if excerpt.locator == *locator {
1165                    excerpts.push((excerpt.id.clone(), excerpt.range.clone()));
1166                }
1167            }
1168        }
1169
1170        excerpts
1171    }
1172
1173    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
1174        self.snapshot
1175            .borrow()
1176            .excerpts
1177            .iter()
1178            .map(|entry| entry.id)
1179            .collect()
1180    }
1181
1182    pub fn excerpt_containing(
1183        &self,
1184        position: impl ToOffset,
1185        cx: &AppContext,
1186    ) -> Option<(ExcerptId, Model<Buffer>, Range<text::Anchor>)> {
1187        let snapshot = self.read(cx);
1188        let position = position.to_offset(&snapshot);
1189
1190        let mut cursor = snapshot.excerpts.cursor::<usize>();
1191        cursor.seek(&position, Bias::Right, &());
1192        cursor
1193            .item()
1194            .or_else(|| snapshot.excerpts.last())
1195            .map(|excerpt| {
1196                (
1197                    excerpt.id.clone(),
1198                    self.buffers
1199                        .borrow()
1200                        .get(&excerpt.buffer_id)
1201                        .unwrap()
1202                        .buffer
1203                        .clone(),
1204                    excerpt.range.context.clone(),
1205                )
1206            })
1207    }
1208
1209    // If point is at the end of the buffer, the last excerpt is returned
1210    pub fn point_to_buffer_offset<T: ToOffset>(
1211        &self,
1212        point: T,
1213        cx: &AppContext,
1214    ) -> Option<(Model<Buffer>, usize, ExcerptId)> {
1215        let snapshot = self.read(cx);
1216        let offset = point.to_offset(&snapshot);
1217        let mut cursor = snapshot.excerpts.cursor::<usize>();
1218        cursor.seek(&offset, Bias::Right, &());
1219        if cursor.item().is_none() {
1220            cursor.prev(&());
1221        }
1222
1223        cursor.item().map(|excerpt| {
1224            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1225            let buffer_point = excerpt_start + offset - *cursor.start();
1226            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
1227
1228            (buffer, buffer_point, excerpt.id)
1229        })
1230    }
1231
1232    pub fn range_to_buffer_ranges<T: ToOffset>(
1233        &self,
1234        range: Range<T>,
1235        cx: &AppContext,
1236    ) -> Vec<(Model<Buffer>, Range<usize>, ExcerptId)> {
1237        let snapshot = self.read(cx);
1238        let start = range.start.to_offset(&snapshot);
1239        let end = range.end.to_offset(&snapshot);
1240
1241        let mut result = Vec::new();
1242        let mut cursor = snapshot.excerpts.cursor::<usize>();
1243        cursor.seek(&start, Bias::Right, &());
1244        if cursor.item().is_none() {
1245            cursor.prev(&());
1246        }
1247
1248        while let Some(excerpt) = cursor.item() {
1249            if *cursor.start() > end {
1250                break;
1251            }
1252
1253            let mut end_before_newline = cursor.end(&());
1254            if excerpt.has_trailing_newline {
1255                end_before_newline -= 1;
1256            }
1257            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1258            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
1259            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
1260            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
1261            result.push((buffer, start..end, excerpt.id));
1262            cursor.next(&());
1263        }
1264
1265        result
1266    }
1267
1268    pub fn remove_excerpts(
1269        &mut self,
1270        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
1271        cx: &mut ModelContext<Self>,
1272    ) {
1273        self.sync(cx);
1274        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
1275        if ids.is_empty() {
1276            return;
1277        }
1278
1279        let mut buffers = self.buffers.borrow_mut();
1280        let mut snapshot = self.snapshot.borrow_mut();
1281        let mut new_excerpts = SumTree::new();
1282        let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, usize)>();
1283        let mut edits = Vec::new();
1284        let mut excerpt_ids = ids.iter().copied().peekable();
1285
1286        while let Some(excerpt_id) = excerpt_ids.next() {
1287            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1288            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
1289            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1290
1291            if let Some(mut excerpt) = cursor.item() {
1292                if excerpt.id != excerpt_id {
1293                    continue;
1294                }
1295                let mut old_start = cursor.start().1;
1296
1297                // Skip over the removed excerpt.
1298                'remove_excerpts: loop {
1299                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
1300                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
1301                        if buffer_state.excerpts.is_empty() {
1302                            buffers.remove(&excerpt.buffer_id);
1303                        }
1304                    }
1305                    cursor.next(&());
1306
1307                    // Skip over any subsequent excerpts that are also removed.
1308                    while let Some(&next_excerpt_id) = excerpt_ids.peek() {
1309                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
1310                        if let Some(next_excerpt) = cursor.item() {
1311                            if next_excerpt.locator == *next_locator {
1312                                excerpt_ids.next();
1313                                excerpt = next_excerpt;
1314                                continue 'remove_excerpts;
1315                            }
1316                        }
1317                        break;
1318                    }
1319
1320                    break;
1321                }
1322
1323                // When removing the last excerpt, remove the trailing newline from
1324                // the previous excerpt.
1325                if cursor.item().is_none() && old_start > 0 {
1326                    old_start -= 1;
1327                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
1328                }
1329
1330                // Push an edit for the removal of this run of excerpts.
1331                let old_end = cursor.start().1;
1332                let new_start = new_excerpts.summary().text.len;
1333                edits.push(Edit {
1334                    old: old_start..old_end,
1335                    new: new_start..new_start,
1336                });
1337            }
1338        }
1339        let suffix = cursor.suffix(&());
1340        let changed_trailing_excerpt = suffix.is_empty();
1341        new_excerpts.append(suffix, &());
1342        drop(cursor);
1343        snapshot.excerpts = new_excerpts;
1344
1345        if changed_trailing_excerpt {
1346            snapshot.trailing_excerpt_update_count += 1;
1347        }
1348
1349        self.subscriptions.publish_mut(edits);
1350        cx.emit(Event::Edited {
1351            singleton_buffer_edited: false,
1352        });
1353        cx.emit(Event::ExcerptsRemoved { ids });
1354        cx.notify();
1355    }
1356
1357    pub fn wait_for_anchors<'a>(
1358        &self,
1359        anchors: impl 'a + Iterator<Item = Anchor>,
1360        cx: &mut ModelContext<Self>,
1361    ) -> impl 'static + Future<Output = Result<()>> {
1362        let borrow = self.buffers.borrow();
1363        let mut error = None;
1364        let mut futures = Vec::new();
1365        for anchor in anchors {
1366            if let Some(buffer_id) = anchor.buffer_id {
1367                if let Some(buffer) = borrow.get(&buffer_id) {
1368                    buffer.buffer.update(cx, |buffer, _| {
1369                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
1370                    });
1371                } else {
1372                    error = Some(anyhow!(
1373                        "buffer {buffer_id} is not part of this multi-buffer"
1374                    ));
1375                    break;
1376                }
1377            }
1378        }
1379        async move {
1380            if let Some(error) = error {
1381                Err(error)?;
1382            }
1383            for future in futures {
1384                future.await?;
1385            }
1386            Ok(())
1387        }
1388    }
1389
1390    pub fn text_anchor_for_position<T: ToOffset>(
1391        &self,
1392        position: T,
1393        cx: &AppContext,
1394    ) -> Option<(Model<Buffer>, language::Anchor)> {
1395        let snapshot = self.read(cx);
1396        let anchor = snapshot.anchor_before(position);
1397        let buffer = self
1398            .buffers
1399            .borrow()
1400            .get(&anchor.buffer_id?)?
1401            .buffer
1402            .clone();
1403        Some((buffer, anchor.text_anchor))
1404    }
1405
1406    fn on_buffer_event(
1407        &mut self,
1408        buffer: Model<Buffer>,
1409        event: &language::Event,
1410        cx: &mut ModelContext<Self>,
1411    ) {
1412        cx.emit(match event {
1413            language::Event::Edited => Event::Edited {
1414                singleton_buffer_edited: true,
1415            },
1416            language::Event::DirtyChanged => Event::DirtyChanged,
1417            language::Event::Saved => Event::Saved,
1418            language::Event::FileHandleChanged => Event::FileHandleChanged,
1419            language::Event::Reloaded => Event::Reloaded,
1420            language::Event::DiffBaseChanged => Event::DiffBaseChanged,
1421            language::Event::LanguageChanged => Event::LanguageChanged,
1422            language::Event::Reparsed => Event::Reparsed,
1423            language::Event::DiagnosticsUpdated => Event::DiagnosticsUpdated,
1424            language::Event::Closed => Event::Closed,
1425            language::Event::CapabilityChanged => {
1426                self.capability = buffer.read(cx).capability();
1427                Event::CapabilityChanged
1428            }
1429
1430            //
1431            language::Event::Operation(_) => return,
1432        });
1433    }
1434
1435    pub fn all_buffers(&self) -> HashSet<Model<Buffer>> {
1436        self.buffers
1437            .borrow()
1438            .values()
1439            .map(|state| state.buffer.clone())
1440            .collect()
1441    }
1442
1443    pub fn buffer(&self, buffer_id: BufferId) -> Option<Model<Buffer>> {
1444        self.buffers
1445            .borrow()
1446            .get(&buffer_id)
1447            .map(|state| state.buffer.clone())
1448    }
1449
1450    pub fn is_completion_trigger(&self, position: Anchor, text: &str, cx: &AppContext) -> bool {
1451        let mut chars = text.chars();
1452        let char = if let Some(char) = chars.next() {
1453            char
1454        } else {
1455            return false;
1456        };
1457        if chars.next().is_some() {
1458            return false;
1459        }
1460
1461        let snapshot = self.snapshot(cx);
1462        let position = position.to_offset(&snapshot);
1463        let scope = snapshot.language_scope_at(position);
1464        if char_kind(&scope, char) == CharKind::Word {
1465            return true;
1466        }
1467
1468        let anchor = snapshot.anchor_before(position);
1469        anchor
1470            .buffer_id
1471            .and_then(|buffer_id| {
1472                let buffer = self.buffers.borrow().get(&buffer_id)?.buffer.clone();
1473                Some(
1474                    buffer
1475                        .read(cx)
1476                        .completion_triggers()
1477                        .iter()
1478                        .any(|string| string == text),
1479                )
1480            })
1481            .unwrap_or(false)
1482    }
1483
1484    pub fn language_at<'a, T: ToOffset>(
1485        &self,
1486        point: T,
1487        cx: &'a AppContext,
1488    ) -> Option<Arc<Language>> {
1489        self.point_to_buffer_offset(point, cx)
1490            .and_then(|(buffer, offset, _)| buffer.read(cx).language_at(offset))
1491    }
1492
1493    pub fn settings_at<'a, T: ToOffset>(
1494        &self,
1495        point: T,
1496        cx: &'a AppContext,
1497    ) -> &'a LanguageSettings {
1498        let mut language = None;
1499        let mut file = None;
1500        if let Some((buffer, offset, _)) = self.point_to_buffer_offset(point, cx) {
1501            let buffer = buffer.read(cx);
1502            language = buffer.language_at(offset);
1503            file = buffer.file();
1504        }
1505        language_settings(language.as_ref(), file, cx)
1506    }
1507
1508    pub fn for_each_buffer(&self, mut f: impl FnMut(&Model<Buffer>)) {
1509        self.buffers
1510            .borrow()
1511            .values()
1512            .for_each(|state| f(&state.buffer))
1513    }
1514
1515    pub fn title<'a>(&'a self, cx: &'a AppContext) -> Cow<'a, str> {
1516        if let Some(title) = self.title.as_ref() {
1517            return title.into();
1518        }
1519
1520        if let Some(buffer) = self.as_singleton() {
1521            if let Some(file) = buffer.read(cx).file() {
1522                return file.file_name(cx).to_string_lossy();
1523            }
1524        }
1525
1526        "untitled".into()
1527    }
1528
1529    #[cfg(any(test, feature = "test-support"))]
1530    pub fn is_parsing(&self, cx: &AppContext) -> bool {
1531        self.as_singleton().unwrap().read(cx).is_parsing()
1532    }
1533
1534    fn sync(&self, cx: &AppContext) {
1535        let mut snapshot = self.snapshot.borrow_mut();
1536        let mut excerpts_to_edit = Vec::new();
1537        let mut reparsed = false;
1538        let mut diagnostics_updated = false;
1539        let mut git_diff_updated = false;
1540        let mut is_dirty = false;
1541        let mut has_conflict = false;
1542        let mut edited = false;
1543        let mut buffers = self.buffers.borrow_mut();
1544        for buffer_state in buffers.values_mut() {
1545            let buffer = buffer_state.buffer.read(cx);
1546            let version = buffer.version();
1547            let parse_count = buffer.parse_count();
1548            let selections_update_count = buffer.selections_update_count();
1549            let diagnostics_update_count = buffer.diagnostics_update_count();
1550            let file_update_count = buffer.file_update_count();
1551            let git_diff_update_count = buffer.git_diff_update_count();
1552
1553            let buffer_edited = version.changed_since(&buffer_state.last_version);
1554            let buffer_reparsed = parse_count > buffer_state.last_parse_count;
1555            let buffer_selections_updated =
1556                selections_update_count > buffer_state.last_selections_update_count;
1557            let buffer_diagnostics_updated =
1558                diagnostics_update_count > buffer_state.last_diagnostics_update_count;
1559            let buffer_file_updated = file_update_count > buffer_state.last_file_update_count;
1560            let buffer_git_diff_updated =
1561                git_diff_update_count > buffer_state.last_git_diff_update_count;
1562            if buffer_edited
1563                || buffer_reparsed
1564                || buffer_selections_updated
1565                || buffer_diagnostics_updated
1566                || buffer_file_updated
1567                || buffer_git_diff_updated
1568            {
1569                buffer_state.last_version = version;
1570                buffer_state.last_parse_count = parse_count;
1571                buffer_state.last_selections_update_count = selections_update_count;
1572                buffer_state.last_diagnostics_update_count = diagnostics_update_count;
1573                buffer_state.last_file_update_count = file_update_count;
1574                buffer_state.last_git_diff_update_count = git_diff_update_count;
1575                excerpts_to_edit.extend(
1576                    buffer_state
1577                        .excerpts
1578                        .iter()
1579                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
1580                );
1581            }
1582
1583            edited |= buffer_edited;
1584            reparsed |= buffer_reparsed;
1585            diagnostics_updated |= buffer_diagnostics_updated;
1586            git_diff_updated |= buffer_git_diff_updated;
1587            is_dirty |= buffer.is_dirty();
1588            has_conflict |= buffer.has_conflict();
1589        }
1590        if edited {
1591            snapshot.edit_count += 1;
1592        }
1593        if reparsed {
1594            snapshot.parse_count += 1;
1595        }
1596        if diagnostics_updated {
1597            snapshot.diagnostics_update_count += 1;
1598        }
1599        if git_diff_updated {
1600            snapshot.git_diff_update_count += 1;
1601        }
1602        snapshot.is_dirty = is_dirty;
1603        snapshot.has_conflict = has_conflict;
1604
1605        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
1606
1607        let mut edits = Vec::new();
1608        let mut new_excerpts = SumTree::new();
1609        let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, usize)>();
1610
1611        for (locator, buffer, buffer_edited) in excerpts_to_edit {
1612            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
1613            let old_excerpt = cursor.item().unwrap();
1614            let buffer = buffer.read(cx);
1615            let buffer_id = buffer.remote_id();
1616
1617            let mut new_excerpt;
1618            if buffer_edited {
1619                edits.extend(
1620                    buffer
1621                        .edits_since_in_range::<usize>(
1622                            old_excerpt.buffer.version(),
1623                            old_excerpt.range.context.clone(),
1624                        )
1625                        .map(|mut edit| {
1626                            let excerpt_old_start = cursor.start().1;
1627                            let excerpt_new_start = new_excerpts.summary().text.len;
1628                            edit.old.start += excerpt_old_start;
1629                            edit.old.end += excerpt_old_start;
1630                            edit.new.start += excerpt_new_start;
1631                            edit.new.end += excerpt_new_start;
1632                            edit
1633                        }),
1634                );
1635
1636                new_excerpt = Excerpt::new(
1637                    old_excerpt.id,
1638                    locator.clone(),
1639                    buffer_id,
1640                    buffer.snapshot(),
1641                    old_excerpt.range.clone(),
1642                    old_excerpt.has_trailing_newline,
1643                );
1644            } else {
1645                new_excerpt = old_excerpt.clone();
1646                new_excerpt.buffer = buffer.snapshot();
1647            }
1648
1649            new_excerpts.push(new_excerpt, &());
1650            cursor.next(&());
1651        }
1652        new_excerpts.append(cursor.suffix(&()), &());
1653
1654        drop(cursor);
1655        snapshot.excerpts = new_excerpts;
1656
1657        self.subscriptions.publish(edits);
1658    }
1659}
1660
1661#[cfg(any(test, feature = "test-support"))]
1662impl MultiBuffer {
1663    pub fn build_simple(text: &str, cx: &mut gpui::AppContext) -> Model<Self> {
1664        let buffer = cx
1665            .new_model(|cx| Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), text));
1666        cx.new_model(|cx| Self::singleton(buffer, cx))
1667    }
1668
1669    pub fn build_multi<const COUNT: usize>(
1670        excerpts: [(&str, Vec<Range<Point>>); COUNT],
1671        cx: &mut gpui::AppContext,
1672    ) -> Model<Self> {
1673        let multi = cx.new_model(|_| Self::new(0, Capability::ReadWrite));
1674        for (text, ranges) in excerpts {
1675            let buffer = cx.new_model(|cx| {
1676                Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), text)
1677            });
1678            let excerpt_ranges = ranges.into_iter().map(|range| ExcerptRange {
1679                context: range,
1680                primary: None,
1681            });
1682            multi.update(cx, |multi, cx| {
1683                multi.push_excerpts(buffer, excerpt_ranges, cx)
1684            });
1685        }
1686
1687        multi
1688    }
1689
1690    pub fn build_from_buffer(buffer: Model<Buffer>, cx: &mut gpui::AppContext) -> Model<Self> {
1691        cx.new_model(|cx| Self::singleton(buffer, cx))
1692    }
1693
1694    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::AppContext) -> Model<Self> {
1695        cx.new_model(|cx| {
1696            let mut multibuffer = MultiBuffer::new(0, Capability::ReadWrite);
1697            let mutation_count = rng.gen_range(1..=5);
1698            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
1699            multibuffer
1700        })
1701    }
1702
1703    pub fn randomly_edit(
1704        &mut self,
1705        rng: &mut impl rand::Rng,
1706        edit_count: usize,
1707        cx: &mut ModelContext<Self>,
1708    ) {
1709        use util::RandomCharIter;
1710
1711        let snapshot = self.read(cx);
1712        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
1713        let mut last_end = None;
1714        for _ in 0..edit_count {
1715            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
1716                break;
1717            }
1718
1719            let new_start = last_end.map_or(0, |last_end| last_end + 1);
1720            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
1721            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
1722            last_end = Some(end);
1723
1724            let mut range = start..end;
1725            if rng.gen_bool(0.2) {
1726                mem::swap(&mut range.start, &mut range.end);
1727            }
1728
1729            let new_text_len = rng.gen_range(0..10);
1730            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1731
1732            edits.push((range, new_text.into()));
1733        }
1734        log::info!("mutating multi-buffer with {:?}", edits);
1735        drop(snapshot);
1736
1737        self.edit(edits, None, cx);
1738    }
1739
1740    pub fn randomly_edit_excerpts(
1741        &mut self,
1742        rng: &mut impl rand::Rng,
1743        mutation_count: usize,
1744        cx: &mut ModelContext<Self>,
1745    ) {
1746        use rand::prelude::*;
1747        use std::env;
1748        use util::RandomCharIter;
1749
1750        let max_excerpts = env::var("MAX_EXCERPTS")
1751            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
1752            .unwrap_or(5);
1753
1754        let mut buffers = Vec::new();
1755        for _ in 0..mutation_count {
1756            if rng.gen_bool(0.05) {
1757                log::info!("Clearing multi-buffer");
1758                self.clear(cx);
1759                continue;
1760            }
1761
1762            let excerpt_ids = self.excerpt_ids();
1763            if excerpt_ids.is_empty() || (rng.gen() && excerpt_ids.len() < max_excerpts) {
1764                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
1765                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
1766                    buffers.push(cx.new_model(|cx| {
1767                        Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), text)
1768                    }));
1769                    let buffer = buffers.last().unwrap().read(cx);
1770                    log::info!(
1771                        "Creating new buffer {} with text: {:?}",
1772                        buffer.remote_id(),
1773                        buffer.text()
1774                    );
1775                    buffers.last().unwrap().clone()
1776                } else {
1777                    self.buffers
1778                        .borrow()
1779                        .values()
1780                        .choose(rng)
1781                        .unwrap()
1782                        .buffer
1783                        .clone()
1784                };
1785
1786                let buffer = buffer_handle.read(cx);
1787                let buffer_text = buffer.text();
1788                let ranges = (0..rng.gen_range(0..5))
1789                    .map(|_| {
1790                        let end_ix =
1791                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
1792                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1793                        ExcerptRange {
1794                            context: start_ix..end_ix,
1795                            primary: None,
1796                        }
1797                    })
1798                    .collect::<Vec<_>>();
1799                log::info!(
1800                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
1801                    buffer_handle.read(cx).remote_id(),
1802                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
1803                    ranges
1804                        .iter()
1805                        .map(|r| &buffer_text[r.context.clone()])
1806                        .collect::<Vec<_>>()
1807                );
1808
1809                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
1810                log::info!("Inserted with ids: {:?}", excerpt_id);
1811            } else {
1812                let remove_count = rng.gen_range(1..=excerpt_ids.len());
1813                let mut excerpts_to_remove = excerpt_ids
1814                    .choose_multiple(rng, remove_count)
1815                    .cloned()
1816                    .collect::<Vec<_>>();
1817                let snapshot = self.snapshot.borrow();
1818                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &*snapshot));
1819                drop(snapshot);
1820                log::info!("Removing excerpts {:?}", excerpts_to_remove);
1821                self.remove_excerpts(excerpts_to_remove, cx);
1822            }
1823        }
1824    }
1825
1826    pub fn randomly_mutate(
1827        &mut self,
1828        rng: &mut impl rand::Rng,
1829        mutation_count: usize,
1830        cx: &mut ModelContext<Self>,
1831    ) {
1832        use rand::prelude::*;
1833
1834        if rng.gen_bool(0.7) || self.singleton {
1835            let buffer = self
1836                .buffers
1837                .borrow()
1838                .values()
1839                .choose(rng)
1840                .map(|state| state.buffer.clone());
1841
1842            if let Some(buffer) = buffer {
1843                buffer.update(cx, |buffer, cx| {
1844                    if rng.gen() {
1845                        buffer.randomly_edit(rng, mutation_count, cx);
1846                    } else {
1847                        buffer.randomly_undo_redo(rng, cx);
1848                    }
1849                });
1850            } else {
1851                self.randomly_edit(rng, mutation_count, cx);
1852            }
1853        } else {
1854            self.randomly_edit_excerpts(rng, mutation_count, cx);
1855        }
1856
1857        self.check_invariants(cx);
1858    }
1859
1860    fn check_invariants(&self, cx: &mut ModelContext<Self>) {
1861        let snapshot = self.read(cx);
1862        let excerpts = snapshot.excerpts.items(&());
1863        let excerpt_ids = snapshot.excerpt_ids.items(&());
1864
1865        for (ix, excerpt) in excerpts.iter().enumerate() {
1866            if ix == 0 {
1867                if excerpt.locator <= Locator::min() {
1868                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
1869                }
1870            } else {
1871                if excerpt.locator <= excerpts[ix - 1].locator {
1872                    panic!("excerpts are out-of-order: {:?}", excerpts);
1873                }
1874            }
1875        }
1876
1877        for (ix, entry) in excerpt_ids.iter().enumerate() {
1878            if ix == 0 {
1879                if entry.id.cmp(&ExcerptId::min(), &*snapshot).is_le() {
1880                    panic!("invalid first excerpt id {:?}", entry.id);
1881                }
1882            } else {
1883                if entry.id <= excerpt_ids[ix - 1].id {
1884                    panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
1885                }
1886            }
1887        }
1888    }
1889}
1890
1891impl EventEmitter<Event> for MultiBuffer {}
1892
1893impl MultiBufferSnapshot {
1894    pub fn text(&self) -> String {
1895        self.chunks(0..self.len(), false)
1896            .map(|chunk| chunk.text)
1897            .collect()
1898    }
1899
1900    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
1901        let mut offset = position.to_offset(self);
1902        let mut cursor = self.excerpts.cursor::<usize>();
1903        cursor.seek(&offset, Bias::Left, &());
1904        let mut excerpt_chunks = cursor.item().map(|excerpt| {
1905            let end_before_footer = cursor.start() + excerpt.text_summary.len;
1906            let start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1907            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
1908            excerpt.buffer.reversed_chunks_in_range(start..end)
1909        });
1910        iter::from_fn(move || {
1911            if offset == *cursor.start() {
1912                cursor.prev(&());
1913                let excerpt = cursor.item()?;
1914                excerpt_chunks = Some(
1915                    excerpt
1916                        .buffer
1917                        .reversed_chunks_in_range(excerpt.range.context.clone()),
1918                );
1919            }
1920
1921            let excerpt = cursor.item().unwrap();
1922            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
1923                offset -= 1;
1924                Some("\n")
1925            } else {
1926                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
1927                offset -= chunk.len();
1928                Some(chunk)
1929            }
1930        })
1931        .flat_map(|c| c.chars().rev())
1932    }
1933
1934    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
1935        let offset = position.to_offset(self);
1936        self.text_for_range(offset..self.len())
1937            .flat_map(|chunk| chunk.chars())
1938    }
1939
1940    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
1941        self.chunks(range, false).map(|chunk| chunk.text)
1942    }
1943
1944    pub fn is_line_blank(&self, row: u32) -> bool {
1945        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1946            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1947    }
1948
1949    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1950    where
1951        T: ToOffset,
1952    {
1953        let position = position.to_offset(self);
1954        position == self.clip_offset(position, Bias::Left)
1955            && self
1956                .bytes_in_range(position..self.len())
1957                .flatten()
1958                .copied()
1959                .take(needle.len())
1960                .eq(needle.bytes())
1961    }
1962
1963    pub fn surrounding_word<T: ToOffset>(&self, start: T) -> (Range<usize>, Option<CharKind>) {
1964        let mut start = start.to_offset(self);
1965        let mut end = start;
1966        let mut next_chars = self.chars_at(start).peekable();
1967        let mut prev_chars = self.reversed_chars_at(start).peekable();
1968
1969        let scope = self.language_scope_at(start);
1970        let kind = |c| char_kind(&scope, c);
1971        let word_kind = cmp::max(
1972            prev_chars.peek().copied().map(kind),
1973            next_chars.peek().copied().map(kind),
1974        );
1975
1976        for ch in prev_chars {
1977            if Some(kind(ch)) == word_kind && ch != '\n' {
1978                start -= ch.len_utf8();
1979            } else {
1980                break;
1981            }
1982        }
1983
1984        for ch in next_chars {
1985            if Some(kind(ch)) == word_kind && ch != '\n' {
1986                end += ch.len_utf8();
1987            } else {
1988                break;
1989            }
1990        }
1991
1992        (start..end, word_kind)
1993    }
1994
1995    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
1996        if self.singleton {
1997            self.excerpts
1998                .iter()
1999                .next()
2000                .map(|e| (&e.id, e.buffer_id, &e.buffer))
2001        } else {
2002            None
2003        }
2004    }
2005
2006    pub fn len(&self) -> usize {
2007        self.excerpts.summary().text.len
2008    }
2009
2010    pub fn is_empty(&self) -> bool {
2011        self.excerpts.summary().text.len == 0
2012    }
2013
2014    pub fn max_buffer_row(&self) -> u32 {
2015        self.excerpts.summary().max_buffer_row
2016    }
2017
2018    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
2019        if let Some((_, _, buffer)) = self.as_singleton() {
2020            return buffer.clip_offset(offset, bias);
2021        }
2022
2023        let mut cursor = self.excerpts.cursor::<usize>();
2024        cursor.seek(&offset, Bias::Right, &());
2025        let overshoot = if let Some(excerpt) = cursor.item() {
2026            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2027            let buffer_offset = excerpt
2028                .buffer
2029                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
2030            buffer_offset.saturating_sub(excerpt_start)
2031        } else {
2032            0
2033        };
2034        cursor.start() + overshoot
2035    }
2036
2037    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
2038        if let Some((_, _, buffer)) = self.as_singleton() {
2039            return buffer.clip_point(point, bias);
2040        }
2041
2042        let mut cursor = self.excerpts.cursor::<Point>();
2043        cursor.seek(&point, Bias::Right, &());
2044        let overshoot = if let Some(excerpt) = cursor.item() {
2045            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
2046            let buffer_point = excerpt
2047                .buffer
2048                .clip_point(excerpt_start + (point - cursor.start()), bias);
2049            buffer_point.saturating_sub(excerpt_start)
2050        } else {
2051            Point::zero()
2052        };
2053        *cursor.start() + overshoot
2054    }
2055
2056    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
2057        if let Some((_, _, buffer)) = self.as_singleton() {
2058            return buffer.clip_offset_utf16(offset, bias);
2059        }
2060
2061        let mut cursor = self.excerpts.cursor::<OffsetUtf16>();
2062        cursor.seek(&offset, Bias::Right, &());
2063        let overshoot = if let Some(excerpt) = cursor.item() {
2064            let excerpt_start = excerpt.range.context.start.to_offset_utf16(&excerpt.buffer);
2065            let buffer_offset = excerpt
2066                .buffer
2067                .clip_offset_utf16(excerpt_start + (offset - cursor.start()), bias);
2068            OffsetUtf16(buffer_offset.0.saturating_sub(excerpt_start.0))
2069        } else {
2070            OffsetUtf16(0)
2071        };
2072        *cursor.start() + overshoot
2073    }
2074
2075    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
2076        if let Some((_, _, buffer)) = self.as_singleton() {
2077            return buffer.clip_point_utf16(point, bias);
2078        }
2079
2080        let mut cursor = self.excerpts.cursor::<PointUtf16>();
2081        cursor.seek(&point.0, Bias::Right, &());
2082        let overshoot = if let Some(excerpt) = cursor.item() {
2083            let excerpt_start = excerpt
2084                .buffer
2085                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
2086            let buffer_point = excerpt
2087                .buffer
2088                .clip_point_utf16(Unclipped(excerpt_start + (point.0 - cursor.start())), bias);
2089            buffer_point.saturating_sub(excerpt_start)
2090        } else {
2091            PointUtf16::zero()
2092        };
2093        *cursor.start() + overshoot
2094    }
2095
2096    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
2097        let range = range.start.to_offset(self)..range.end.to_offset(self);
2098        let mut excerpts = self.excerpts.cursor::<usize>();
2099        excerpts.seek(&range.start, Bias::Right, &());
2100
2101        let mut chunk = &[][..];
2102        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
2103            let mut excerpt_bytes = excerpt
2104                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
2105            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
2106            Some(excerpt_bytes)
2107        } else {
2108            None
2109        };
2110        MultiBufferBytes {
2111            range,
2112            excerpts,
2113            excerpt_bytes,
2114            chunk,
2115        }
2116    }
2117
2118    pub fn reversed_bytes_in_range<T: ToOffset>(
2119        &self,
2120        range: Range<T>,
2121    ) -> ReversedMultiBufferBytes {
2122        let range = range.start.to_offset(self)..range.end.to_offset(self);
2123        let mut excerpts = self.excerpts.cursor::<usize>();
2124        excerpts.seek(&range.end, Bias::Left, &());
2125
2126        let mut chunk = &[][..];
2127        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
2128            let mut excerpt_bytes = excerpt.reversed_bytes_in_range(
2129                range.start - excerpts.start()..range.end - excerpts.start(),
2130            );
2131            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
2132            Some(excerpt_bytes)
2133        } else {
2134            None
2135        };
2136
2137        ReversedMultiBufferBytes {
2138            range,
2139            excerpts,
2140            excerpt_bytes,
2141            chunk,
2142        }
2143    }
2144
2145    pub fn buffer_rows(&self, start_row: u32) -> MultiBufferRows {
2146        let mut result = MultiBufferRows {
2147            buffer_row_range: 0..0,
2148            excerpts: self.excerpts.cursor(),
2149        };
2150        result.seek(start_row);
2151        result
2152    }
2153
2154    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
2155        let range = range.start.to_offset(self)..range.end.to_offset(self);
2156        let mut chunks = MultiBufferChunks {
2157            range: range.clone(),
2158            excerpts: self.excerpts.cursor(),
2159            excerpt_chunks: None,
2160            language_aware,
2161        };
2162        chunks.seek(range.start);
2163        chunks
2164    }
2165
2166    pub fn offset_to_point(&self, offset: usize) -> Point {
2167        if let Some((_, _, buffer)) = self.as_singleton() {
2168            return buffer.offset_to_point(offset);
2169        }
2170
2171        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
2172        cursor.seek(&offset, Bias::Right, &());
2173        if let Some(excerpt) = cursor.item() {
2174            let (start_offset, start_point) = cursor.start();
2175            let overshoot = offset - start_offset;
2176            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2177            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2178            let buffer_point = excerpt
2179                .buffer
2180                .offset_to_point(excerpt_start_offset + overshoot);
2181            *start_point + (buffer_point - excerpt_start_point)
2182        } else {
2183            self.excerpts.summary().text.lines
2184        }
2185    }
2186
2187    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
2188        if let Some((_, _, buffer)) = self.as_singleton() {
2189            return buffer.offset_to_point_utf16(offset);
2190        }
2191
2192        let mut cursor = self.excerpts.cursor::<(usize, PointUtf16)>();
2193        cursor.seek(&offset, Bias::Right, &());
2194        if let Some(excerpt) = cursor.item() {
2195            let (start_offset, start_point) = cursor.start();
2196            let overshoot = offset - start_offset;
2197            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2198            let excerpt_start_point = excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
2199            let buffer_point = excerpt
2200                .buffer
2201                .offset_to_point_utf16(excerpt_start_offset + overshoot);
2202            *start_point + (buffer_point - excerpt_start_point)
2203        } else {
2204            self.excerpts.summary().text.lines_utf16()
2205        }
2206    }
2207
2208    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
2209        if let Some((_, _, buffer)) = self.as_singleton() {
2210            return buffer.point_to_point_utf16(point);
2211        }
2212
2213        let mut cursor = self.excerpts.cursor::<(Point, PointUtf16)>();
2214        cursor.seek(&point, Bias::Right, &());
2215        if let Some(excerpt) = cursor.item() {
2216            let (start_offset, start_point) = cursor.start();
2217            let overshoot = point - start_offset;
2218            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2219            let excerpt_start_point_utf16 =
2220                excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
2221            let buffer_point = excerpt
2222                .buffer
2223                .point_to_point_utf16(excerpt_start_point + overshoot);
2224            *start_point + (buffer_point - excerpt_start_point_utf16)
2225        } else {
2226            self.excerpts.summary().text.lines_utf16()
2227        }
2228    }
2229
2230    pub fn point_to_offset(&self, point: Point) -> usize {
2231        if let Some((_, _, buffer)) = self.as_singleton() {
2232            return buffer.point_to_offset(point);
2233        }
2234
2235        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
2236        cursor.seek(&point, Bias::Right, &());
2237        if let Some(excerpt) = cursor.item() {
2238            let (start_point, start_offset) = cursor.start();
2239            let overshoot = point - start_point;
2240            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2241            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
2242            let buffer_offset = excerpt
2243                .buffer
2244                .point_to_offset(excerpt_start_point + overshoot);
2245            *start_offset + buffer_offset - excerpt_start_offset
2246        } else {
2247            self.excerpts.summary().text.len
2248        }
2249    }
2250
2251    pub fn offset_utf16_to_offset(&self, offset_utf16: OffsetUtf16) -> usize {
2252        if let Some((_, _, buffer)) = self.as_singleton() {
2253            return buffer.offset_utf16_to_offset(offset_utf16);
2254        }
2255
2256        let mut cursor = self.excerpts.cursor::<(OffsetUtf16, usize)>();
2257        cursor.seek(&offset_utf16, Bias::Right, &());
2258        if let Some(excerpt) = cursor.item() {
2259            let (start_offset_utf16, start_offset) = cursor.start();
2260            let overshoot = offset_utf16 - start_offset_utf16;
2261            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2262            let excerpt_start_offset_utf16 =
2263                excerpt.buffer.offset_to_offset_utf16(excerpt_start_offset);
2264            let buffer_offset = excerpt
2265                .buffer
2266                .offset_utf16_to_offset(excerpt_start_offset_utf16 + overshoot);
2267            *start_offset + (buffer_offset - excerpt_start_offset)
2268        } else {
2269            self.excerpts.summary().text.len
2270        }
2271    }
2272
2273    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
2274        if let Some((_, _, buffer)) = self.as_singleton() {
2275            return buffer.offset_to_offset_utf16(offset);
2276        }
2277
2278        let mut cursor = self.excerpts.cursor::<(usize, OffsetUtf16)>();
2279        cursor.seek(&offset, Bias::Right, &());
2280        if let Some(excerpt) = cursor.item() {
2281            let (start_offset, start_offset_utf16) = cursor.start();
2282            let overshoot = offset - start_offset;
2283            let excerpt_start_offset_utf16 =
2284                excerpt.range.context.start.to_offset_utf16(&excerpt.buffer);
2285            let excerpt_start_offset = excerpt
2286                .buffer
2287                .offset_utf16_to_offset(excerpt_start_offset_utf16);
2288            let buffer_offset_utf16 = excerpt
2289                .buffer
2290                .offset_to_offset_utf16(excerpt_start_offset + overshoot);
2291            *start_offset_utf16 + (buffer_offset_utf16 - excerpt_start_offset_utf16)
2292        } else {
2293            self.excerpts.summary().text.len_utf16
2294        }
2295    }
2296
2297    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
2298        if let Some((_, _, buffer)) = self.as_singleton() {
2299            return buffer.point_utf16_to_offset(point);
2300        }
2301
2302        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
2303        cursor.seek(&point, Bias::Right, &());
2304        if let Some(excerpt) = cursor.item() {
2305            let (start_point, start_offset) = cursor.start();
2306            let overshoot = point - start_point;
2307            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
2308            let excerpt_start_point = excerpt
2309                .buffer
2310                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
2311            let buffer_offset = excerpt
2312                .buffer
2313                .point_utf16_to_offset(excerpt_start_point + overshoot);
2314            *start_offset + (buffer_offset - excerpt_start_offset)
2315        } else {
2316            self.excerpts.summary().text.len
2317        }
2318    }
2319
2320    pub fn point_to_buffer_offset<T: ToOffset>(
2321        &self,
2322        point: T,
2323    ) -> Option<(&BufferSnapshot, usize)> {
2324        let offset = point.to_offset(self);
2325        let mut cursor = self.excerpts.cursor::<usize>();
2326        cursor.seek(&offset, Bias::Right, &());
2327        if cursor.item().is_none() {
2328            cursor.prev(&());
2329        }
2330
2331        cursor.item().map(|excerpt| {
2332            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2333            let buffer_point = excerpt_start + offset - *cursor.start();
2334            (&excerpt.buffer, buffer_point)
2335        })
2336    }
2337
2338    pub fn suggested_indents(
2339        &self,
2340        rows: impl IntoIterator<Item = u32>,
2341        cx: &AppContext,
2342    ) -> BTreeMap<u32, IndentSize> {
2343        let mut result = BTreeMap::new();
2344
2345        let mut rows_for_excerpt = Vec::new();
2346        let mut cursor = self.excerpts.cursor::<Point>();
2347        let mut rows = rows.into_iter().peekable();
2348        let mut prev_row = u32::MAX;
2349        let mut prev_language_indent_size = IndentSize::default();
2350
2351        while let Some(row) = rows.next() {
2352            cursor.seek(&Point::new(row, 0), Bias::Right, &());
2353            let excerpt = match cursor.item() {
2354                Some(excerpt) => excerpt,
2355                _ => continue,
2356            };
2357
2358            // Retrieve the language and indent size once for each disjoint region being indented.
2359            let single_indent_size = if row.saturating_sub(1) == prev_row {
2360                prev_language_indent_size
2361            } else {
2362                excerpt
2363                    .buffer
2364                    .language_indent_size_at(Point::new(row, 0), cx)
2365            };
2366            prev_language_indent_size = single_indent_size;
2367            prev_row = row;
2368
2369            let start_buffer_row = excerpt.range.context.start.to_point(&excerpt.buffer).row;
2370            let start_multibuffer_row = cursor.start().row;
2371
2372            rows_for_excerpt.push(row);
2373            while let Some(next_row) = rows.peek().copied() {
2374                if cursor.end(&()).row > next_row {
2375                    rows_for_excerpt.push(next_row);
2376                    rows.next();
2377                } else {
2378                    break;
2379                }
2380            }
2381
2382            let buffer_rows = rows_for_excerpt
2383                .drain(..)
2384                .map(|row| start_buffer_row + row - start_multibuffer_row);
2385            let buffer_indents = excerpt
2386                .buffer
2387                .suggested_indents(buffer_rows, single_indent_size);
2388            let multibuffer_indents = buffer_indents
2389                .into_iter()
2390                .map(|(row, indent)| (start_multibuffer_row + row - start_buffer_row, indent));
2391            result.extend(multibuffer_indents);
2392        }
2393
2394        result
2395    }
2396
2397    pub fn indent_size_for_line(&self, row: u32) -> IndentSize {
2398        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
2399            let mut size = buffer.indent_size_for_line(range.start.row);
2400            size.len = size
2401                .len
2402                .min(range.end.column)
2403                .saturating_sub(range.start.column);
2404            size
2405        } else {
2406            IndentSize::spaces(0)
2407        }
2408    }
2409
2410    pub fn prev_non_blank_row(&self, mut row: u32) -> Option<u32> {
2411        while row > 0 {
2412            row -= 1;
2413            if !self.is_line_blank(row) {
2414                return Some(row);
2415            }
2416        }
2417        None
2418    }
2419
2420    pub fn line_len(&self, row: u32) -> u32 {
2421        if let Some((_, range)) = self.buffer_line_for_row(row) {
2422            range.end.column - range.start.column
2423        } else {
2424            0
2425        }
2426    }
2427
2428    pub fn buffer_line_for_row(&self, row: u32) -> Option<(&BufferSnapshot, Range<Point>)> {
2429        let mut cursor = self.excerpts.cursor::<Point>();
2430        let point = Point::new(row, 0);
2431        cursor.seek(&point, Bias::Right, &());
2432        if cursor.item().is_none() && *cursor.start() == point {
2433            cursor.prev(&());
2434        }
2435        if let Some(excerpt) = cursor.item() {
2436            let overshoot = row - cursor.start().row;
2437            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
2438            let excerpt_end = excerpt.range.context.end.to_point(&excerpt.buffer);
2439            let buffer_row = excerpt_start.row + overshoot;
2440            let line_start = Point::new(buffer_row, 0);
2441            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
2442            return Some((
2443                &excerpt.buffer,
2444                line_start.max(excerpt_start)..line_end.min(excerpt_end),
2445            ));
2446        }
2447        None
2448    }
2449
2450    pub fn max_point(&self) -> Point {
2451        self.text_summary().lines
2452    }
2453
2454    pub fn text_summary(&self) -> TextSummary {
2455        self.excerpts.summary().text.clone()
2456    }
2457
2458    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
2459    where
2460        D: TextDimension,
2461        O: ToOffset,
2462    {
2463        let mut summary = D::default();
2464        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
2465        let mut cursor = self.excerpts.cursor::<usize>();
2466        cursor.seek(&range.start, Bias::Right, &());
2467        if let Some(excerpt) = cursor.item() {
2468            let mut end_before_newline = cursor.end(&());
2469            if excerpt.has_trailing_newline {
2470                end_before_newline -= 1;
2471            }
2472
2473            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2474            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
2475            let end_in_excerpt =
2476                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
2477            summary.add_assign(
2478                &excerpt
2479                    .buffer
2480                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
2481            );
2482
2483            if range.end > end_before_newline {
2484                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
2485            }
2486
2487            cursor.next(&());
2488        }
2489
2490        if range.end > *cursor.start() {
2491            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
2492                &range.end,
2493                Bias::Right,
2494                &(),
2495            )));
2496            if let Some(excerpt) = cursor.item() {
2497                range.end = cmp::max(*cursor.start(), range.end);
2498
2499                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2500                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
2501                summary.add_assign(
2502                    &excerpt
2503                        .buffer
2504                        .text_summary_for_range(excerpt_start..end_in_excerpt),
2505                );
2506            }
2507        }
2508
2509        summary
2510    }
2511
2512    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
2513    where
2514        D: TextDimension + Ord + Sub<D, Output = D>,
2515    {
2516        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
2517        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
2518
2519        cursor.seek(locator, Bias::Left, &());
2520        if cursor.item().is_none() {
2521            cursor.next(&());
2522        }
2523
2524        let mut position = D::from_text_summary(&cursor.start().text);
2525        if let Some(excerpt) = cursor.item() {
2526            if excerpt.id == anchor.excerpt_id {
2527                let excerpt_buffer_start =
2528                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
2529                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
2530                let buffer_position = cmp::min(
2531                    excerpt_buffer_end,
2532                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
2533                );
2534                if buffer_position > excerpt_buffer_start {
2535                    position.add_assign(&(buffer_position - excerpt_buffer_start));
2536                }
2537            }
2538        }
2539        position
2540    }
2541
2542    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
2543    where
2544        D: TextDimension + Ord + Sub<D, Output = D>,
2545        I: 'a + IntoIterator<Item = &'a Anchor>,
2546    {
2547        if let Some((_, _, buffer)) = self.as_singleton() {
2548            return buffer
2549                .summaries_for_anchors(anchors.into_iter().map(|a| &a.text_anchor))
2550                .collect();
2551        }
2552
2553        let mut anchors = anchors.into_iter().peekable();
2554        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
2555        let mut summaries = Vec::new();
2556        while let Some(anchor) = anchors.peek() {
2557            let excerpt_id = anchor.excerpt_id;
2558            let excerpt_anchors = iter::from_fn(|| {
2559                let anchor = anchors.peek()?;
2560                if anchor.excerpt_id == excerpt_id {
2561                    Some(&anchors.next().unwrap().text_anchor)
2562                } else {
2563                    None
2564                }
2565            });
2566
2567            let locator = self.excerpt_locator_for_id(excerpt_id);
2568            cursor.seek_forward(locator, Bias::Left, &());
2569            if cursor.item().is_none() {
2570                cursor.next(&());
2571            }
2572
2573            let position = D::from_text_summary(&cursor.start().text);
2574            if let Some(excerpt) = cursor.item() {
2575                if excerpt.id == excerpt_id {
2576                    let excerpt_buffer_start =
2577                        excerpt.range.context.start.summary::<D>(&excerpt.buffer);
2578                    let excerpt_buffer_end =
2579                        excerpt.range.context.end.summary::<D>(&excerpt.buffer);
2580                    summaries.extend(
2581                        excerpt
2582                            .buffer
2583                            .summaries_for_anchors::<D, _>(excerpt_anchors)
2584                            .map(move |summary| {
2585                                let summary = cmp::min(excerpt_buffer_end.clone(), summary);
2586                                let mut position = position.clone();
2587                                let excerpt_buffer_start = excerpt_buffer_start.clone();
2588                                if summary > excerpt_buffer_start {
2589                                    position.add_assign(&(summary - excerpt_buffer_start));
2590                                }
2591                                position
2592                            }),
2593                    );
2594                    continue;
2595                }
2596            }
2597
2598            summaries.extend(excerpt_anchors.map(|_| position.clone()));
2599        }
2600
2601        summaries
2602    }
2603
2604    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
2605    where
2606        I: 'a + IntoIterator<Item = &'a Anchor>,
2607    {
2608        let mut anchors = anchors.into_iter().enumerate().peekable();
2609        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
2610        cursor.next(&());
2611
2612        let mut result = Vec::new();
2613
2614        while let Some((_, anchor)) = anchors.peek() {
2615            let old_excerpt_id = anchor.excerpt_id;
2616
2617            // Find the location where this anchor's excerpt should be.
2618            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
2619            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
2620
2621            if cursor.item().is_none() {
2622                cursor.next(&());
2623            }
2624
2625            let next_excerpt = cursor.item();
2626            let prev_excerpt = cursor.prev_item();
2627
2628            // Process all of the anchors for this excerpt.
2629            while let Some((_, anchor)) = anchors.peek() {
2630                if anchor.excerpt_id != old_excerpt_id {
2631                    break;
2632                }
2633                let (anchor_ix, anchor) = anchors.next().unwrap();
2634                let mut anchor = *anchor;
2635
2636                // Leave min and max anchors unchanged if invalid or
2637                // if the old excerpt still exists at this location
2638                let mut kept_position = next_excerpt
2639                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
2640                    || old_excerpt_id == ExcerptId::max()
2641                    || old_excerpt_id == ExcerptId::min();
2642
2643                // If the old excerpt no longer exists at this location, then attempt to
2644                // find an equivalent position for this anchor in an adjacent excerpt.
2645                if !kept_position {
2646                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
2647                        if excerpt.contains(&anchor) {
2648                            anchor.excerpt_id = excerpt.id.clone();
2649                            kept_position = true;
2650                            break;
2651                        }
2652                    }
2653                }
2654
2655                // If there's no adjacent excerpt that contains the anchor's position,
2656                // then report that the anchor has lost its position.
2657                if !kept_position {
2658                    anchor = if let Some(excerpt) = next_excerpt {
2659                        let mut text_anchor = excerpt
2660                            .range
2661                            .context
2662                            .start
2663                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2664                        if text_anchor
2665                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
2666                            .is_gt()
2667                        {
2668                            text_anchor = excerpt.range.context.end;
2669                        }
2670                        Anchor {
2671                            buffer_id: Some(excerpt.buffer_id),
2672                            excerpt_id: excerpt.id.clone(),
2673                            text_anchor,
2674                        }
2675                    } else if let Some(excerpt) = prev_excerpt {
2676                        let mut text_anchor = excerpt
2677                            .range
2678                            .context
2679                            .end
2680                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2681                        if text_anchor
2682                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
2683                            .is_lt()
2684                        {
2685                            text_anchor = excerpt.range.context.start;
2686                        }
2687                        Anchor {
2688                            buffer_id: Some(excerpt.buffer_id),
2689                            excerpt_id: excerpt.id.clone(),
2690                            text_anchor,
2691                        }
2692                    } else if anchor.text_anchor.bias == Bias::Left {
2693                        Anchor::min()
2694                    } else {
2695                        Anchor::max()
2696                    };
2697                }
2698
2699                result.push((anchor_ix, anchor, kept_position));
2700            }
2701        }
2702        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
2703        result
2704    }
2705
2706    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
2707        self.anchor_at(position, Bias::Left)
2708    }
2709
2710    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
2711        self.anchor_at(position, Bias::Right)
2712    }
2713
2714    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
2715        let offset = position.to_offset(self);
2716        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
2717            return Anchor {
2718                buffer_id: Some(buffer_id),
2719                excerpt_id: excerpt_id.clone(),
2720                text_anchor: buffer.anchor_at(offset, bias),
2721            };
2722        }
2723
2724        let mut cursor = self.excerpts.cursor::<(usize, Option<ExcerptId>)>();
2725        cursor.seek(&offset, Bias::Right, &());
2726        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
2727            cursor.prev(&());
2728        }
2729        if let Some(excerpt) = cursor.item() {
2730            let mut overshoot = offset.saturating_sub(cursor.start().0);
2731            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
2732                overshoot -= 1;
2733                bias = Bias::Right;
2734            }
2735
2736            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2737            let text_anchor =
2738                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
2739            Anchor {
2740                buffer_id: Some(excerpt.buffer_id),
2741                excerpt_id: excerpt.id.clone(),
2742                text_anchor,
2743            }
2744        } else if offset == 0 && bias == Bias::Left {
2745            Anchor::min()
2746        } else {
2747            Anchor::max()
2748        }
2749    }
2750
2751    pub fn anchor_in_excerpt(&self, excerpt_id: ExcerptId, text_anchor: text::Anchor) -> Anchor {
2752        let locator = self.excerpt_locator_for_id(excerpt_id);
2753        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
2754        cursor.seek(locator, Bias::Left, &());
2755        if let Some(excerpt) = cursor.item() {
2756            if excerpt.id == excerpt_id {
2757                let text_anchor = excerpt.clip_anchor(text_anchor);
2758                drop(cursor);
2759                return Anchor {
2760                    buffer_id: Some(excerpt.buffer_id),
2761                    excerpt_id,
2762                    text_anchor,
2763                };
2764            }
2765        }
2766        panic!("excerpt not found");
2767    }
2768
2769    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
2770        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
2771            true
2772        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
2773            excerpt.buffer.can_resolve(&anchor.text_anchor)
2774        } else {
2775            false
2776        }
2777    }
2778
2779    pub fn excerpts(
2780        &self,
2781    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
2782        self.excerpts
2783            .iter()
2784            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
2785    }
2786
2787    pub fn excerpt_boundaries_in_range<R, T>(
2788        &self,
2789        range: R,
2790    ) -> impl Iterator<Item = ExcerptBoundary> + '_
2791    where
2792        R: RangeBounds<T>,
2793        T: ToOffset,
2794    {
2795        let start_offset;
2796        let start = match range.start_bound() {
2797            Bound::Included(start) => {
2798                start_offset = start.to_offset(self);
2799                Bound::Included(start_offset)
2800            }
2801            Bound::Excluded(start) => {
2802                start_offset = start.to_offset(self);
2803                Bound::Excluded(start_offset)
2804            }
2805            Bound::Unbounded => {
2806                start_offset = 0;
2807                Bound::Unbounded
2808            }
2809        };
2810        let end = match range.end_bound() {
2811            Bound::Included(end) => Bound::Included(end.to_offset(self)),
2812            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
2813            Bound::Unbounded => Bound::Unbounded,
2814        };
2815        let bounds = (start, end);
2816
2817        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
2818        cursor.seek(&start_offset, Bias::Right, &());
2819        if cursor.item().is_none() {
2820            cursor.prev(&());
2821        }
2822        if !bounds.contains(&cursor.start().0) {
2823            cursor.next(&());
2824        }
2825
2826        let mut prev_buffer_id = cursor.prev_item().map(|excerpt| excerpt.buffer_id);
2827        std::iter::from_fn(move || {
2828            if self.singleton {
2829                None
2830            } else if bounds.contains(&cursor.start().0) {
2831                let excerpt = cursor.item()?;
2832                let starts_new_buffer = Some(excerpt.buffer_id) != prev_buffer_id;
2833                let boundary = ExcerptBoundary {
2834                    id: excerpt.id.clone(),
2835                    row: cursor.start().1.row,
2836                    buffer: excerpt.buffer.clone(),
2837                    range: excerpt.range.clone(),
2838                    starts_new_buffer,
2839                };
2840
2841                prev_buffer_id = Some(excerpt.buffer_id);
2842                cursor.next(&());
2843                Some(boundary)
2844            } else {
2845                None
2846            }
2847        })
2848    }
2849
2850    pub fn edit_count(&self) -> usize {
2851        self.edit_count
2852    }
2853
2854    pub fn parse_count(&self) -> usize {
2855        self.parse_count
2856    }
2857
2858    /// Returns the smallest enclosing bracket ranges containing the given range or
2859    /// None if no brackets contain range or the range is not contained in a single
2860    /// excerpt
2861    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
2862        &self,
2863        range: Range<T>,
2864    ) -> Option<(Range<usize>, Range<usize>)> {
2865        let range = range.start.to_offset(self)..range.end.to_offset(self);
2866
2867        // Get the ranges of the innermost pair of brackets.
2868        let mut result: Option<(Range<usize>, Range<usize>)> = None;
2869
2870        let Some(enclosing_bracket_ranges) = self.enclosing_bracket_ranges(range.clone()) else {
2871            return None;
2872        };
2873
2874        for (open, close) in enclosing_bracket_ranges {
2875            let len = close.end - open.start;
2876
2877            if let Some((existing_open, existing_close)) = &result {
2878                let existing_len = existing_close.end - existing_open.start;
2879                if len > existing_len {
2880                    continue;
2881                }
2882            }
2883
2884            result = Some((open, close));
2885        }
2886
2887        result
2888    }
2889
2890    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
2891    /// not contained in a single excerpt
2892    pub fn enclosing_bracket_ranges<'a, T: ToOffset>(
2893        &'a self,
2894        range: Range<T>,
2895    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + 'a> {
2896        let range = range.start.to_offset(self)..range.end.to_offset(self);
2897
2898        self.bracket_ranges(range.clone()).map(|range_pairs| {
2899            range_pairs
2900                .filter(move |(open, close)| open.start <= range.start && close.end >= range.end)
2901        })
2902    }
2903
2904    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
2905    /// not contained in a single excerpt
2906    pub fn bracket_ranges<'a, T: ToOffset>(
2907        &'a self,
2908        range: Range<T>,
2909    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + 'a> {
2910        let range = range.start.to_offset(self)..range.end.to_offset(self);
2911        let excerpt = self.excerpt_containing(range.clone());
2912        excerpt.map(|(excerpt, excerpt_offset)| {
2913            let excerpt_buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2914            let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
2915
2916            let start_in_buffer = excerpt_buffer_start + range.start.saturating_sub(excerpt_offset);
2917            let end_in_buffer = excerpt_buffer_start + range.end.saturating_sub(excerpt_offset);
2918
2919            excerpt
2920                .buffer
2921                .bracket_ranges(start_in_buffer..end_in_buffer)
2922                .filter_map(move |(start_bracket_range, end_bracket_range)| {
2923                    if start_bracket_range.start < excerpt_buffer_start
2924                        || end_bracket_range.end > excerpt_buffer_end
2925                    {
2926                        return None;
2927                    }
2928
2929                    let mut start_bracket_range = start_bracket_range.clone();
2930                    start_bracket_range.start =
2931                        excerpt_offset + (start_bracket_range.start - excerpt_buffer_start);
2932                    start_bracket_range.end =
2933                        excerpt_offset + (start_bracket_range.end - excerpt_buffer_start);
2934
2935                    let mut end_bracket_range = end_bracket_range.clone();
2936                    end_bracket_range.start =
2937                        excerpt_offset + (end_bracket_range.start - excerpt_buffer_start);
2938                    end_bracket_range.end =
2939                        excerpt_offset + (end_bracket_range.end - excerpt_buffer_start);
2940                    Some((start_bracket_range, end_bracket_range))
2941                })
2942        })
2943    }
2944
2945    pub fn diagnostics_update_count(&self) -> usize {
2946        self.diagnostics_update_count
2947    }
2948
2949    pub fn git_diff_update_count(&self) -> usize {
2950        self.git_diff_update_count
2951    }
2952
2953    pub fn trailing_excerpt_update_count(&self) -> usize {
2954        self.trailing_excerpt_update_count
2955    }
2956
2957    pub fn file_at<'a, T: ToOffset>(&'a self, point: T) -> Option<&'a Arc<dyn File>> {
2958        self.point_to_buffer_offset(point)
2959            .and_then(|(buffer, _)| buffer.file())
2960    }
2961
2962    pub fn language_at<'a, T: ToOffset>(&'a self, point: T) -> Option<&'a Arc<Language>> {
2963        self.point_to_buffer_offset(point)
2964            .and_then(|(buffer, offset)| buffer.language_at(offset))
2965    }
2966
2967    pub fn settings_at<'a, T: ToOffset>(
2968        &'a self,
2969        point: T,
2970        cx: &'a AppContext,
2971    ) -> &'a LanguageSettings {
2972        let mut language = None;
2973        let mut file = None;
2974        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
2975            language = buffer.language_at(offset);
2976            file = buffer.file();
2977        }
2978        language_settings(language, file, cx)
2979    }
2980
2981    pub fn language_scope_at<'a, T: ToOffset>(&'a self, point: T) -> Option<LanguageScope> {
2982        self.point_to_buffer_offset(point)
2983            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
2984    }
2985
2986    pub fn language_indent_size_at<T: ToOffset>(
2987        &self,
2988        position: T,
2989        cx: &AppContext,
2990    ) -> Option<IndentSize> {
2991        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
2992        Some(buffer_snapshot.language_indent_size_at(offset, cx))
2993    }
2994
2995    pub fn is_dirty(&self) -> bool {
2996        self.is_dirty
2997    }
2998
2999    pub fn has_conflict(&self) -> bool {
3000        self.has_conflict
3001    }
3002
3003    pub fn diagnostic_group<'a, O>(
3004        &'a self,
3005        group_id: usize,
3006    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
3007    where
3008        O: text::FromAnchor + 'a,
3009    {
3010        self.as_singleton()
3011            .into_iter()
3012            .flat_map(move |(_, _, buffer)| buffer.diagnostic_group(group_id))
3013    }
3014
3015    pub fn diagnostics_in_range<'a, T, O>(
3016        &'a self,
3017        range: Range<T>,
3018        reversed: bool,
3019    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
3020    where
3021        T: 'a + ToOffset,
3022        O: 'a + text::FromAnchor + Ord,
3023    {
3024        self.as_singleton()
3025            .into_iter()
3026            .flat_map(move |(_, _, buffer)| {
3027                buffer.diagnostics_in_range(
3028                    range.start.to_offset(self)..range.end.to_offset(self),
3029                    reversed,
3030                )
3031            })
3032    }
3033
3034    pub fn has_git_diffs(&self) -> bool {
3035        for excerpt in self.excerpts.iter() {
3036            if excerpt.buffer.has_git_diff() {
3037                return true;
3038            }
3039        }
3040        false
3041    }
3042
3043    pub fn git_diff_hunks_in_range_rev<'a>(
3044        &'a self,
3045        row_range: Range<u32>,
3046    ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
3047        let mut cursor = self.excerpts.cursor::<Point>();
3048
3049        cursor.seek(&Point::new(row_range.end, 0), Bias::Left, &());
3050        if cursor.item().is_none() {
3051            cursor.prev(&());
3052        }
3053
3054        std::iter::from_fn(move || {
3055            let excerpt = cursor.item()?;
3056            let multibuffer_start = *cursor.start();
3057            let multibuffer_end = multibuffer_start + excerpt.text_summary.lines;
3058            if multibuffer_start.row >= row_range.end {
3059                return None;
3060            }
3061
3062            let mut buffer_start = excerpt.range.context.start;
3063            let mut buffer_end = excerpt.range.context.end;
3064            let excerpt_start_point = buffer_start.to_point(&excerpt.buffer);
3065            let excerpt_end_point = excerpt_start_point + excerpt.text_summary.lines;
3066
3067            if row_range.start > multibuffer_start.row {
3068                let buffer_start_point =
3069                    excerpt_start_point + Point::new(row_range.start - multibuffer_start.row, 0);
3070                buffer_start = excerpt.buffer.anchor_before(buffer_start_point);
3071            }
3072
3073            if row_range.end < multibuffer_end.row {
3074                let buffer_end_point =
3075                    excerpt_start_point + Point::new(row_range.end - multibuffer_start.row, 0);
3076                buffer_end = excerpt.buffer.anchor_before(buffer_end_point);
3077            }
3078
3079            let buffer_hunks = excerpt
3080                .buffer
3081                .git_diff_hunks_intersecting_range_rev(buffer_start..buffer_end)
3082                .filter_map(move |hunk| {
3083                    let start = multibuffer_start.row
3084                        + hunk
3085                            .buffer_range
3086                            .start
3087                            .saturating_sub(excerpt_start_point.row);
3088                    let end = multibuffer_start.row
3089                        + hunk
3090                            .buffer_range
3091                            .end
3092                            .min(excerpt_end_point.row + 1)
3093                            .saturating_sub(excerpt_start_point.row);
3094
3095                    Some(DiffHunk {
3096                        buffer_range: start..end,
3097                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3098                    })
3099                });
3100
3101            cursor.prev(&());
3102
3103            Some(buffer_hunks)
3104        })
3105        .flatten()
3106    }
3107
3108    pub fn git_diff_hunks_in_range<'a>(
3109        &'a self,
3110        row_range: Range<u32>,
3111    ) -> impl 'a + Iterator<Item = DiffHunk<u32>> {
3112        let mut cursor = self.excerpts.cursor::<Point>();
3113
3114        cursor.seek(&Point::new(row_range.start, 0), Bias::Right, &());
3115
3116        std::iter::from_fn(move || {
3117            let excerpt = cursor.item()?;
3118            let multibuffer_start = *cursor.start();
3119            let multibuffer_end = multibuffer_start + excerpt.text_summary.lines;
3120            if multibuffer_start.row >= row_range.end {
3121                return None;
3122            }
3123
3124            let mut buffer_start = excerpt.range.context.start;
3125            let mut buffer_end = excerpt.range.context.end;
3126            let excerpt_start_point = buffer_start.to_point(&excerpt.buffer);
3127            let excerpt_end_point = excerpt_start_point + excerpt.text_summary.lines;
3128
3129            if row_range.start > multibuffer_start.row {
3130                let buffer_start_point =
3131                    excerpt_start_point + Point::new(row_range.start - multibuffer_start.row, 0);
3132                buffer_start = excerpt.buffer.anchor_before(buffer_start_point);
3133            }
3134
3135            if row_range.end < multibuffer_end.row {
3136                let buffer_end_point =
3137                    excerpt_start_point + Point::new(row_range.end - multibuffer_start.row, 0);
3138                buffer_end = excerpt.buffer.anchor_before(buffer_end_point);
3139            }
3140
3141            let buffer_hunks = excerpt
3142                .buffer
3143                .git_diff_hunks_intersecting_range(buffer_start..buffer_end)
3144                .filter_map(move |hunk| {
3145                    let start = multibuffer_start.row
3146                        + hunk
3147                            .buffer_range
3148                            .start
3149                            .saturating_sub(excerpt_start_point.row);
3150                    let end = multibuffer_start.row
3151                        + hunk
3152                            .buffer_range
3153                            .end
3154                            .min(excerpt_end_point.row + 1)
3155                            .saturating_sub(excerpt_start_point.row);
3156
3157                    Some(DiffHunk {
3158                        buffer_range: start..end,
3159                        diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3160                    })
3161                });
3162
3163            cursor.next(&());
3164
3165            Some(buffer_hunks)
3166        })
3167        .flatten()
3168    }
3169
3170    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
3171        let range = range.start.to_offset(self)..range.end.to_offset(self);
3172
3173        self.excerpt_containing(range.clone())
3174            .and_then(|(excerpt, excerpt_offset)| {
3175                let excerpt_buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
3176                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3177
3178                let start_in_buffer =
3179                    excerpt_buffer_start + range.start.saturating_sub(excerpt_offset);
3180                let end_in_buffer = excerpt_buffer_start + range.end.saturating_sub(excerpt_offset);
3181                let mut ancestor_buffer_range = excerpt
3182                    .buffer
3183                    .range_for_syntax_ancestor(start_in_buffer..end_in_buffer)?;
3184                ancestor_buffer_range.start =
3185                    cmp::max(ancestor_buffer_range.start, excerpt_buffer_start);
3186                ancestor_buffer_range.end = cmp::min(ancestor_buffer_range.end, excerpt_buffer_end);
3187
3188                let start = excerpt_offset + (ancestor_buffer_range.start - excerpt_buffer_start);
3189                let end = excerpt_offset + (ancestor_buffer_range.end - excerpt_buffer_start);
3190                Some(start..end)
3191            })
3192    }
3193
3194    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
3195        let (excerpt_id, _, buffer) = self.as_singleton()?;
3196        let outline = buffer.outline(theme)?;
3197        Some(Outline::new(
3198            outline
3199                .items
3200                .into_iter()
3201                .map(|item| OutlineItem {
3202                    depth: item.depth,
3203                    range: self.anchor_in_excerpt(excerpt_id.clone(), item.range.start)
3204                        ..self.anchor_in_excerpt(excerpt_id.clone(), item.range.end),
3205                    text: item.text,
3206                    highlight_ranges: item.highlight_ranges,
3207                    name_ranges: item.name_ranges,
3208                })
3209                .collect(),
3210        ))
3211    }
3212
3213    pub fn symbols_containing<T: ToOffset>(
3214        &self,
3215        offset: T,
3216        theme: Option<&SyntaxTheme>,
3217    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
3218        let anchor = self.anchor_before(offset);
3219        let excerpt_id = anchor.excerpt_id;
3220        let excerpt = self.excerpt(excerpt_id)?;
3221        Some((
3222            excerpt.buffer_id,
3223            excerpt
3224                .buffer
3225                .symbols_containing(anchor.text_anchor, theme)
3226                .into_iter()
3227                .flatten()
3228                .map(|item| OutlineItem {
3229                    depth: item.depth,
3230                    range: self.anchor_in_excerpt(excerpt_id, item.range.start)
3231                        ..self.anchor_in_excerpt(excerpt_id, item.range.end),
3232                    text: item.text,
3233                    highlight_ranges: item.highlight_ranges,
3234                    name_ranges: item.name_ranges,
3235                })
3236                .collect(),
3237        ))
3238    }
3239
3240    fn excerpt_locator_for_id<'a>(&'a self, id: ExcerptId) -> &'a Locator {
3241        if id == ExcerptId::min() {
3242            Locator::min_ref()
3243        } else if id == ExcerptId::max() {
3244            Locator::max_ref()
3245        } else {
3246            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>();
3247            cursor.seek(&id, Bias::Left, &());
3248            if let Some(entry) = cursor.item() {
3249                if entry.id == id {
3250                    return &entry.locator;
3251                }
3252            }
3253            panic!("invalid excerpt id {:?}", id)
3254        }
3255    }
3256
3257    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
3258        Some(self.excerpt(excerpt_id)?.buffer_id)
3259    }
3260
3261    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
3262        Some(&self.excerpt(excerpt_id)?.buffer)
3263    }
3264
3265    fn excerpt<'a>(&'a self, excerpt_id: ExcerptId) -> Option<&'a Excerpt> {
3266        let mut cursor = self.excerpts.cursor::<Option<&Locator>>();
3267        let locator = self.excerpt_locator_for_id(excerpt_id);
3268        cursor.seek(&Some(locator), Bias::Left, &());
3269        if let Some(excerpt) = cursor.item() {
3270            if excerpt.id == excerpt_id {
3271                return Some(excerpt);
3272            }
3273        }
3274        None
3275    }
3276
3277    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
3278    fn excerpt_containing<'a, T: ToOffset>(
3279        &'a self,
3280        range: Range<T>,
3281    ) -> Option<(&'a Excerpt, usize)> {
3282        let range = range.start.to_offset(self)..range.end.to_offset(self);
3283
3284        let mut cursor = self.excerpts.cursor::<usize>();
3285        cursor.seek(&range.start, Bias::Right, &());
3286        let start_excerpt = cursor.item();
3287
3288        if range.start == range.end {
3289            return start_excerpt.map(|excerpt| (excerpt, *cursor.start()));
3290        }
3291
3292        cursor.seek(&range.end, Bias::Right, &());
3293        let end_excerpt = cursor.item();
3294
3295        start_excerpt
3296            .zip(end_excerpt)
3297            .and_then(|(start_excerpt, end_excerpt)| {
3298                if start_excerpt.id != end_excerpt.id {
3299                    return None;
3300                }
3301
3302                Some((start_excerpt, *cursor.start()))
3303            })
3304    }
3305
3306    pub fn remote_selections_in_range<'a>(
3307        &'a self,
3308        range: &'a Range<Anchor>,
3309    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
3310        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
3311        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
3312        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
3313        cursor.seek(start_locator, Bias::Left, &());
3314        cursor
3315            .take_while(move |excerpt| excerpt.locator <= *end_locator)
3316            .flat_map(move |excerpt| {
3317                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
3318                if excerpt.id == range.start.excerpt_id {
3319                    query_range.start = range.start.text_anchor;
3320                }
3321                if excerpt.id == range.end.excerpt_id {
3322                    query_range.end = range.end.text_anchor;
3323                }
3324
3325                excerpt
3326                    .buffer
3327                    .remote_selections_in_range(query_range)
3328                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
3329                        selections.map(move |selection| {
3330                            let mut start = Anchor {
3331                                buffer_id: Some(excerpt.buffer_id),
3332                                excerpt_id: excerpt.id.clone(),
3333                                text_anchor: selection.start,
3334                            };
3335                            let mut end = Anchor {
3336                                buffer_id: Some(excerpt.buffer_id),
3337                                excerpt_id: excerpt.id.clone(),
3338                                text_anchor: selection.end,
3339                            };
3340                            if range.start.cmp(&start, self).is_gt() {
3341                                start = range.start.clone();
3342                            }
3343                            if range.end.cmp(&end, self).is_lt() {
3344                                end = range.end.clone();
3345                            }
3346
3347                            (
3348                                replica_id,
3349                                line_mode,
3350                                cursor_shape,
3351                                Selection {
3352                                    id: selection.id,
3353                                    start,
3354                                    end,
3355                                    reversed: selection.reversed,
3356                                    goal: selection.goal,
3357                                },
3358                            )
3359                        })
3360                    })
3361            })
3362    }
3363}
3364
3365#[cfg(any(test, feature = "test-support"))]
3366impl MultiBufferSnapshot {
3367    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
3368        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
3369        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
3370        start..end
3371    }
3372}
3373
3374impl History {
3375    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
3376        self.transaction_depth += 1;
3377        if self.transaction_depth == 1 {
3378            let id = self.next_transaction_id.tick();
3379            self.undo_stack.push(Transaction {
3380                id,
3381                buffer_transactions: Default::default(),
3382                first_edit_at: now,
3383                last_edit_at: now,
3384                suppress_grouping: false,
3385            });
3386            Some(id)
3387        } else {
3388            None
3389        }
3390    }
3391
3392    fn end_transaction(
3393        &mut self,
3394        now: Instant,
3395        buffer_transactions: HashMap<BufferId, TransactionId>,
3396    ) -> bool {
3397        assert_ne!(self.transaction_depth, 0);
3398        self.transaction_depth -= 1;
3399        if self.transaction_depth == 0 {
3400            if buffer_transactions.is_empty() {
3401                self.undo_stack.pop();
3402                false
3403            } else {
3404                self.redo_stack.clear();
3405                let transaction = self.undo_stack.last_mut().unwrap();
3406                transaction.last_edit_at = now;
3407                for (buffer_id, transaction_id) in buffer_transactions {
3408                    transaction
3409                        .buffer_transactions
3410                        .entry(buffer_id)
3411                        .or_insert(transaction_id);
3412                }
3413                true
3414            }
3415        } else {
3416            false
3417        }
3418    }
3419
3420    fn push_transaction<'a, T>(
3421        &mut self,
3422        buffer_transactions: T,
3423        now: Instant,
3424        cx: &mut ModelContext<MultiBuffer>,
3425    ) where
3426        T: IntoIterator<Item = (&'a Model<Buffer>, &'a language::Transaction)>,
3427    {
3428        assert_eq!(self.transaction_depth, 0);
3429        let transaction = Transaction {
3430            id: self.next_transaction_id.tick(),
3431            buffer_transactions: buffer_transactions
3432                .into_iter()
3433                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
3434                .collect(),
3435            first_edit_at: now,
3436            last_edit_at: now,
3437            suppress_grouping: false,
3438        };
3439        if !transaction.buffer_transactions.is_empty() {
3440            self.undo_stack.push(transaction);
3441            self.redo_stack.clear();
3442        }
3443    }
3444
3445    fn finalize_last_transaction(&mut self) {
3446        if let Some(transaction) = self.undo_stack.last_mut() {
3447            transaction.suppress_grouping = true;
3448        }
3449    }
3450
3451    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
3452        if let Some(ix) = self
3453            .undo_stack
3454            .iter()
3455            .rposition(|transaction| transaction.id == transaction_id)
3456        {
3457            Some(self.undo_stack.remove(ix))
3458        } else if let Some(ix) = self
3459            .redo_stack
3460            .iter()
3461            .rposition(|transaction| transaction.id == transaction_id)
3462        {
3463            Some(self.redo_stack.remove(ix))
3464        } else {
3465            None
3466        }
3467    }
3468
3469    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
3470        self.undo_stack
3471            .iter_mut()
3472            .find(|transaction| transaction.id == transaction_id)
3473            .or_else(|| {
3474                self.redo_stack
3475                    .iter_mut()
3476                    .find(|transaction| transaction.id == transaction_id)
3477            })
3478    }
3479
3480    fn pop_undo(&mut self) -> Option<&mut Transaction> {
3481        assert_eq!(self.transaction_depth, 0);
3482        if let Some(transaction) = self.undo_stack.pop() {
3483            self.redo_stack.push(transaction);
3484            self.redo_stack.last_mut()
3485        } else {
3486            None
3487        }
3488    }
3489
3490    fn pop_redo(&mut self) -> Option<&mut Transaction> {
3491        assert_eq!(self.transaction_depth, 0);
3492        if let Some(transaction) = self.redo_stack.pop() {
3493            self.undo_stack.push(transaction);
3494            self.undo_stack.last_mut()
3495        } else {
3496            None
3497        }
3498    }
3499
3500    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
3501        let ix = self
3502            .undo_stack
3503            .iter()
3504            .rposition(|transaction| transaction.id == transaction_id)?;
3505        let transaction = self.undo_stack.remove(ix);
3506        self.redo_stack.push(transaction);
3507        self.redo_stack.last()
3508    }
3509
3510    fn group(&mut self) -> Option<TransactionId> {
3511        let mut count = 0;
3512        let mut transactions = self.undo_stack.iter();
3513        if let Some(mut transaction) = transactions.next_back() {
3514            while let Some(prev_transaction) = transactions.next_back() {
3515                if !prev_transaction.suppress_grouping
3516                    && transaction.first_edit_at - prev_transaction.last_edit_at
3517                        <= self.group_interval
3518                {
3519                    transaction = prev_transaction;
3520                    count += 1;
3521                } else {
3522                    break;
3523                }
3524            }
3525        }
3526        self.group_trailing(count)
3527    }
3528
3529    fn group_until(&mut self, transaction_id: TransactionId) {
3530        let mut count = 0;
3531        for transaction in self.undo_stack.iter().rev() {
3532            if transaction.id == transaction_id {
3533                self.group_trailing(count);
3534                break;
3535            } else if transaction.suppress_grouping {
3536                break;
3537            } else {
3538                count += 1;
3539            }
3540        }
3541    }
3542
3543    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
3544        let new_len = self.undo_stack.len() - n;
3545        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
3546        if let Some(last_transaction) = transactions_to_keep.last_mut() {
3547            if let Some(transaction) = transactions_to_merge.last() {
3548                last_transaction.last_edit_at = transaction.last_edit_at;
3549            }
3550            for to_merge in transactions_to_merge {
3551                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
3552                    last_transaction
3553                        .buffer_transactions
3554                        .entry(*buffer_id)
3555                        .or_insert(*transaction_id);
3556                }
3557            }
3558        }
3559
3560        self.undo_stack.truncate(new_len);
3561        self.undo_stack.last().map(|t| t.id)
3562    }
3563}
3564
3565impl Excerpt {
3566    fn new(
3567        id: ExcerptId,
3568        locator: Locator,
3569        buffer_id: BufferId,
3570        buffer: BufferSnapshot,
3571        range: ExcerptRange<text::Anchor>,
3572        has_trailing_newline: bool,
3573    ) -> Self {
3574        Excerpt {
3575            id,
3576            locator,
3577            max_buffer_row: range.context.end.to_point(&buffer).row,
3578            text_summary: buffer
3579                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
3580            buffer_id,
3581            buffer,
3582            range,
3583            has_trailing_newline,
3584        }
3585    }
3586
3587    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
3588        let content_start = self.range.context.start.to_offset(&self.buffer);
3589        let chunks_start = content_start + range.start;
3590        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
3591
3592        let footer_height = if self.has_trailing_newline
3593            && range.start <= self.text_summary.len
3594            && range.end > self.text_summary.len
3595        {
3596            1
3597        } else {
3598            0
3599        };
3600
3601        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
3602
3603        ExcerptChunks {
3604            content_chunks,
3605            footer_height,
3606        }
3607    }
3608
3609    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
3610        let content_start = self.range.context.start.to_offset(&self.buffer);
3611        let bytes_start = content_start + range.start;
3612        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
3613        let footer_height = if self.has_trailing_newline
3614            && range.start <= self.text_summary.len
3615            && range.end > self.text_summary.len
3616        {
3617            1
3618        } else {
3619            0
3620        };
3621        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
3622
3623        ExcerptBytes {
3624            content_bytes,
3625            footer_height,
3626        }
3627    }
3628
3629    fn reversed_bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
3630        let content_start = self.range.context.start.to_offset(&self.buffer);
3631        let bytes_start = content_start + range.start;
3632        let bytes_end = content_start + cmp::min(range.end, self.text_summary.len);
3633        let footer_height = if self.has_trailing_newline
3634            && range.start <= self.text_summary.len
3635            && range.end > self.text_summary.len
3636        {
3637            1
3638        } else {
3639            0
3640        };
3641        let content_bytes = self.buffer.reversed_bytes_in_range(bytes_start..bytes_end);
3642
3643        ExcerptBytes {
3644            content_bytes,
3645            footer_height,
3646        }
3647    }
3648
3649    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
3650        if text_anchor
3651            .cmp(&self.range.context.start, &self.buffer)
3652            .is_lt()
3653        {
3654            self.range.context.start
3655        } else if text_anchor
3656            .cmp(&self.range.context.end, &self.buffer)
3657            .is_gt()
3658        {
3659            self.range.context.end
3660        } else {
3661            text_anchor
3662        }
3663    }
3664
3665    fn contains(&self, anchor: &Anchor) -> bool {
3666        Some(self.buffer_id) == anchor.buffer_id
3667            && self
3668                .range
3669                .context
3670                .start
3671                .cmp(&anchor.text_anchor, &self.buffer)
3672                .is_le()
3673            && self
3674                .range
3675                .context
3676                .end
3677                .cmp(&anchor.text_anchor, &self.buffer)
3678                .is_ge()
3679    }
3680}
3681
3682impl ExcerptId {
3683    pub fn min() -> Self {
3684        Self(0)
3685    }
3686
3687    pub fn max() -> Self {
3688        Self(usize::MAX)
3689    }
3690
3691    pub fn to_proto(&self) -> u64 {
3692        self.0 as _
3693    }
3694
3695    pub fn from_proto(proto: u64) -> Self {
3696        Self(proto as _)
3697    }
3698
3699    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
3700        let a = snapshot.excerpt_locator_for_id(*self);
3701        let b = snapshot.excerpt_locator_for_id(*other);
3702        a.cmp(b).then_with(|| self.0.cmp(&other.0))
3703    }
3704}
3705
3706impl Into<usize> for ExcerptId {
3707    fn into(self) -> usize {
3708        self.0
3709    }
3710}
3711
3712impl fmt::Debug for Excerpt {
3713    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
3714        f.debug_struct("Excerpt")
3715            .field("id", &self.id)
3716            .field("locator", &self.locator)
3717            .field("buffer_id", &self.buffer_id)
3718            .field("range", &self.range)
3719            .field("text_summary", &self.text_summary)
3720            .field("has_trailing_newline", &self.has_trailing_newline)
3721            .finish()
3722    }
3723}
3724
3725impl sum_tree::Item for Excerpt {
3726    type Summary = ExcerptSummary;
3727
3728    fn summary(&self) -> Self::Summary {
3729        let mut text = self.text_summary.clone();
3730        if self.has_trailing_newline {
3731            text += TextSummary::from("\n");
3732        }
3733        ExcerptSummary {
3734            excerpt_id: self.id,
3735            excerpt_locator: self.locator.clone(),
3736            max_buffer_row: self.max_buffer_row,
3737            text,
3738        }
3739    }
3740}
3741
3742impl sum_tree::Item for ExcerptIdMapping {
3743    type Summary = ExcerptId;
3744
3745    fn summary(&self) -> Self::Summary {
3746        self.id
3747    }
3748}
3749
3750impl sum_tree::KeyedItem for ExcerptIdMapping {
3751    type Key = ExcerptId;
3752
3753    fn key(&self) -> Self::Key {
3754        self.id
3755    }
3756}
3757
3758impl sum_tree::Summary for ExcerptId {
3759    type Context = ();
3760
3761    fn add_summary(&mut self, other: &Self, _: &()) {
3762        *self = *other;
3763    }
3764}
3765
3766impl sum_tree::Summary for ExcerptSummary {
3767    type Context = ();
3768
3769    fn add_summary(&mut self, summary: &Self, _: &()) {
3770        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
3771        self.excerpt_locator = summary.excerpt_locator.clone();
3772        self.text.add_summary(&summary.text, &());
3773        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
3774    }
3775}
3776
3777impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
3778    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3779        *self += &summary.text;
3780    }
3781}
3782
3783impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
3784    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3785        *self += summary.text.len;
3786    }
3787}
3788
3789impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
3790    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
3791        Ord::cmp(self, &cursor_location.text.len)
3792    }
3793}
3794
3795impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
3796    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
3797        Ord::cmp(&Some(self), cursor_location)
3798    }
3799}
3800
3801impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Locator {
3802    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
3803        Ord::cmp(self, &cursor_location.excerpt_locator)
3804    }
3805}
3806
3807impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for OffsetUtf16 {
3808    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3809        *self += summary.text.len_utf16;
3810    }
3811}
3812
3813impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
3814    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3815        *self += summary.text.lines;
3816    }
3817}
3818
3819impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
3820    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3821        *self += summary.text.lines_utf16()
3822    }
3823}
3824
3825impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
3826    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3827        *self = Some(&summary.excerpt_locator);
3828    }
3829}
3830
3831impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
3832    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
3833        *self = Some(summary.excerpt_id);
3834    }
3835}
3836
3837impl<'a> MultiBufferRows<'a> {
3838    pub fn seek(&mut self, row: u32) {
3839        self.buffer_row_range = 0..0;
3840
3841        self.excerpts
3842            .seek_forward(&Point::new(row, 0), Bias::Right, &());
3843        if self.excerpts.item().is_none() {
3844            self.excerpts.prev(&());
3845
3846            if self.excerpts.item().is_none() && row == 0 {
3847                self.buffer_row_range = 0..1;
3848                return;
3849            }
3850        }
3851
3852        if let Some(excerpt) = self.excerpts.item() {
3853            let overshoot = row - self.excerpts.start().row;
3854            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
3855            self.buffer_row_range.start = excerpt_start + overshoot;
3856            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
3857        }
3858    }
3859}
3860
3861impl<'a> Iterator for MultiBufferRows<'a> {
3862    type Item = Option<u32>;
3863
3864    fn next(&mut self) -> Option<Self::Item> {
3865        loop {
3866            if !self.buffer_row_range.is_empty() {
3867                let row = Some(self.buffer_row_range.start);
3868                self.buffer_row_range.start += 1;
3869                return Some(row);
3870            }
3871            self.excerpts.item()?;
3872            self.excerpts.next(&());
3873            let excerpt = self.excerpts.item()?;
3874            self.buffer_row_range.start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
3875            self.buffer_row_range.end =
3876                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
3877        }
3878    }
3879}
3880
3881impl<'a> MultiBufferChunks<'a> {
3882    pub fn offset(&self) -> usize {
3883        self.range.start
3884    }
3885
3886    pub fn seek(&mut self, offset: usize) {
3887        self.range.start = offset;
3888        self.excerpts.seek(&offset, Bias::Right, &());
3889        if let Some(excerpt) = self.excerpts.item() {
3890            self.excerpt_chunks = Some(excerpt.chunks_in_range(
3891                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
3892                self.language_aware,
3893            ));
3894        } else {
3895            self.excerpt_chunks = None;
3896        }
3897    }
3898}
3899
3900impl<'a> Iterator for MultiBufferChunks<'a> {
3901    type Item = Chunk<'a>;
3902
3903    fn next(&mut self) -> Option<Self::Item> {
3904        if self.range.is_empty() {
3905            None
3906        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
3907            self.range.start += chunk.text.len();
3908            Some(chunk)
3909        } else {
3910            self.excerpts.next(&());
3911            let excerpt = self.excerpts.item()?;
3912            self.excerpt_chunks = Some(excerpt.chunks_in_range(
3913                0..self.range.end - self.excerpts.start(),
3914                self.language_aware,
3915            ));
3916            self.next()
3917        }
3918    }
3919}
3920
3921impl<'a> MultiBufferBytes<'a> {
3922    fn consume(&mut self, len: usize) {
3923        self.range.start += len;
3924        self.chunk = &self.chunk[len..];
3925
3926        if !self.range.is_empty() && self.chunk.is_empty() {
3927            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
3928                self.chunk = chunk;
3929            } else {
3930                self.excerpts.next(&());
3931                if let Some(excerpt) = self.excerpts.item() {
3932                    let mut excerpt_bytes =
3933                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
3934                    self.chunk = excerpt_bytes.next().unwrap();
3935                    self.excerpt_bytes = Some(excerpt_bytes);
3936                }
3937            }
3938        }
3939    }
3940}
3941
3942impl<'a> Iterator for MultiBufferBytes<'a> {
3943    type Item = &'a [u8];
3944
3945    fn next(&mut self) -> Option<Self::Item> {
3946        let chunk = self.chunk;
3947        if chunk.is_empty() {
3948            None
3949        } else {
3950            self.consume(chunk.len());
3951            Some(chunk)
3952        }
3953    }
3954}
3955
3956impl<'a> io::Read for MultiBufferBytes<'a> {
3957    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
3958        let len = cmp::min(buf.len(), self.chunk.len());
3959        buf[..len].copy_from_slice(&self.chunk[..len]);
3960        if len > 0 {
3961            self.consume(len);
3962        }
3963        Ok(len)
3964    }
3965}
3966
3967impl<'a> ReversedMultiBufferBytes<'a> {
3968    fn consume(&mut self, len: usize) {
3969        self.range.end -= len;
3970        self.chunk = &self.chunk[..self.chunk.len() - len];
3971
3972        if !self.range.is_empty() && self.chunk.is_empty() {
3973            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
3974                self.chunk = chunk;
3975            } else {
3976                self.excerpts.next(&());
3977                if let Some(excerpt) = self.excerpts.item() {
3978                    let mut excerpt_bytes =
3979                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
3980                    self.chunk = excerpt_bytes.next().unwrap();
3981                    self.excerpt_bytes = Some(excerpt_bytes);
3982                }
3983            }
3984        }
3985    }
3986}
3987
3988impl<'a> io::Read for ReversedMultiBufferBytes<'a> {
3989    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
3990        let len = cmp::min(buf.len(), self.chunk.len());
3991        buf[..len].copy_from_slice(&self.chunk[..len]);
3992        buf[..len].reverse();
3993        if len > 0 {
3994            self.consume(len);
3995        }
3996        Ok(len)
3997    }
3998}
3999impl<'a> Iterator for ExcerptBytes<'a> {
4000    type Item = &'a [u8];
4001
4002    fn next(&mut self) -> Option<Self::Item> {
4003        if let Some(chunk) = self.content_bytes.next() {
4004            if !chunk.is_empty() {
4005                return Some(chunk);
4006            }
4007        }
4008
4009        if self.footer_height > 0 {
4010            let result = &NEWLINES[..self.footer_height];
4011            self.footer_height = 0;
4012            return Some(result);
4013        }
4014
4015        None
4016    }
4017}
4018
4019impl<'a> Iterator for ExcerptChunks<'a> {
4020    type Item = Chunk<'a>;
4021
4022    fn next(&mut self) -> Option<Self::Item> {
4023        if let Some(chunk) = self.content_chunks.next() {
4024            return Some(chunk);
4025        }
4026
4027        if self.footer_height > 0 {
4028            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
4029            self.footer_height = 0;
4030            return Some(Chunk {
4031                text,
4032                ..Default::default()
4033            });
4034        }
4035
4036        None
4037    }
4038}
4039
4040impl ToOffset for Point {
4041    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4042        snapshot.point_to_offset(*self)
4043    }
4044}
4045
4046impl ToOffset for usize {
4047    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4048        assert!(*self <= snapshot.len(), "offset is out of range");
4049        *self
4050    }
4051}
4052
4053impl ToOffset for OffsetUtf16 {
4054    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4055        snapshot.offset_utf16_to_offset(*self)
4056    }
4057}
4058
4059impl ToOffset for PointUtf16 {
4060    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
4061        snapshot.point_utf16_to_offset(*self)
4062    }
4063}
4064
4065impl ToOffsetUtf16 for OffsetUtf16 {
4066    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4067        *self
4068    }
4069}
4070
4071impl ToOffsetUtf16 for usize {
4072    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
4073        snapshot.offset_to_offset_utf16(*self)
4074    }
4075}
4076
4077impl ToPoint for usize {
4078    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
4079        snapshot.offset_to_point(*self)
4080    }
4081}
4082
4083impl ToPoint for Point {
4084    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
4085        *self
4086    }
4087}
4088
4089impl ToPointUtf16 for usize {
4090    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4091        snapshot.offset_to_point_utf16(*self)
4092    }
4093}
4094
4095impl ToPointUtf16 for Point {
4096    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
4097        snapshot.point_to_point_utf16(*self)
4098    }
4099}
4100
4101impl ToPointUtf16 for PointUtf16 {
4102    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
4103        *self
4104    }
4105}
4106
4107fn build_excerpt_ranges<T>(
4108    buffer: &BufferSnapshot,
4109    ranges: &[Range<T>],
4110    context_line_count: u32,
4111) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
4112where
4113    T: text::ToPoint,
4114{
4115    let max_point = buffer.max_point();
4116    let mut range_counts = Vec::new();
4117    let mut excerpt_ranges = Vec::new();
4118    let mut range_iter = ranges
4119        .iter()
4120        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
4121        .peekable();
4122    while let Some(range) = range_iter.next() {
4123        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
4124        let mut excerpt_end = Point::new(range.end.row + 1 + context_line_count, 0).min(max_point);
4125        let mut ranges_in_excerpt = 1;
4126
4127        while let Some(next_range) = range_iter.peek() {
4128            if next_range.start.row <= excerpt_end.row + context_line_count {
4129                excerpt_end =
4130                    Point::new(next_range.end.row + 1 + context_line_count, 0).min(max_point);
4131                ranges_in_excerpt += 1;
4132                range_iter.next();
4133            } else {
4134                break;
4135            }
4136        }
4137
4138        excerpt_ranges.push(ExcerptRange {
4139            context: excerpt_start..excerpt_end,
4140            primary: Some(range),
4141        });
4142        range_counts.push(ranges_in_excerpt);
4143    }
4144
4145    (excerpt_ranges, range_counts)
4146}
4147
4148#[cfg(test)]
4149mod tests {
4150    use super::*;
4151    use futures::StreamExt;
4152    use gpui::{AppContext, Context, TestAppContext};
4153    use language::{Buffer, Rope};
4154    use parking_lot::RwLock;
4155    use rand::prelude::*;
4156    use settings::SettingsStore;
4157    use std::env;
4158    use util::test::sample_text;
4159
4160    #[gpui::test]
4161    fn test_singleton(cx: &mut AppContext) {
4162        let buffer = cx.new_model(|cx| {
4163            Buffer::new(
4164                0,
4165                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4166                sample_text(6, 6, 'a'),
4167            )
4168        });
4169        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
4170
4171        let snapshot = multibuffer.read(cx).snapshot(cx);
4172        assert_eq!(snapshot.text(), buffer.read(cx).text());
4173
4174        assert_eq!(
4175            snapshot.buffer_rows(0).collect::<Vec<_>>(),
4176            (0..buffer.read(cx).row_count())
4177                .map(Some)
4178                .collect::<Vec<_>>()
4179        );
4180
4181        buffer.update(cx, |buffer, cx| buffer.edit([(1..3, "XXX\n")], None, cx));
4182        let snapshot = multibuffer.read(cx).snapshot(cx);
4183
4184        assert_eq!(snapshot.text(), buffer.read(cx).text());
4185        assert_eq!(
4186            snapshot.buffer_rows(0).collect::<Vec<_>>(),
4187            (0..buffer.read(cx).row_count())
4188                .map(Some)
4189                .collect::<Vec<_>>()
4190        );
4191    }
4192
4193    #[gpui::test]
4194    fn test_remote(cx: &mut AppContext) {
4195        let host_buffer =
4196            cx.new_model(|cx| Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "a"));
4197        let guest_buffer = cx.new_model(|cx| {
4198            let state = host_buffer.read(cx).to_proto();
4199            let ops = cx
4200                .background_executor()
4201                .block(host_buffer.read(cx).serialize_ops(None, cx));
4202            let mut buffer = Buffer::from_proto(1, Capability::ReadWrite, state, None).unwrap();
4203            buffer
4204                .apply_ops(
4205                    ops.into_iter()
4206                        .map(|op| language::proto::deserialize_operation(op).unwrap()),
4207                    cx,
4208                )
4209                .unwrap();
4210            buffer
4211        });
4212        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
4213        let snapshot = multibuffer.read(cx).snapshot(cx);
4214        assert_eq!(snapshot.text(), "a");
4215
4216        guest_buffer.update(cx, |buffer, cx| buffer.edit([(1..1, "b")], None, cx));
4217        let snapshot = multibuffer.read(cx).snapshot(cx);
4218        assert_eq!(snapshot.text(), "ab");
4219
4220        guest_buffer.update(cx, |buffer, cx| buffer.edit([(2..2, "c")], None, cx));
4221        let snapshot = multibuffer.read(cx).snapshot(cx);
4222        assert_eq!(snapshot.text(), "abc");
4223    }
4224
4225    #[gpui::test]
4226    fn test_excerpt_boundaries_and_clipping(cx: &mut AppContext) {
4227        let buffer_1 = cx.new_model(|cx| {
4228            Buffer::new(
4229                0,
4230                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4231                sample_text(6, 6, 'a'),
4232            )
4233        });
4234        let buffer_2 = cx.new_model(|cx| {
4235            Buffer::new(
4236                0,
4237                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4238                sample_text(6, 6, 'g'),
4239            )
4240        });
4241        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4242
4243        let events = Arc::new(RwLock::new(Vec::<Event>::new()));
4244        multibuffer.update(cx, |_, cx| {
4245            let events = events.clone();
4246            cx.subscribe(&multibuffer, move |_, _, event, _| {
4247                if let Event::Edited { .. } = event {
4248                    events.write().push(event.clone())
4249                }
4250            })
4251            .detach();
4252        });
4253
4254        let subscription = multibuffer.update(cx, |multibuffer, cx| {
4255            let subscription = multibuffer.subscribe();
4256            multibuffer.push_excerpts(
4257                buffer_1.clone(),
4258                [ExcerptRange {
4259                    context: Point::new(1, 2)..Point::new(2, 5),
4260                    primary: None,
4261                }],
4262                cx,
4263            );
4264            assert_eq!(
4265                subscription.consume().into_inner(),
4266                [Edit {
4267                    old: 0..0,
4268                    new: 0..10
4269                }]
4270            );
4271
4272            multibuffer.push_excerpts(
4273                buffer_1.clone(),
4274                [ExcerptRange {
4275                    context: Point::new(3, 3)..Point::new(4, 4),
4276                    primary: None,
4277                }],
4278                cx,
4279            );
4280            multibuffer.push_excerpts(
4281                buffer_2.clone(),
4282                [ExcerptRange {
4283                    context: Point::new(3, 1)..Point::new(3, 3),
4284                    primary: None,
4285                }],
4286                cx,
4287            );
4288            assert_eq!(
4289                subscription.consume().into_inner(),
4290                [Edit {
4291                    old: 10..10,
4292                    new: 10..22
4293                }]
4294            );
4295
4296            subscription
4297        });
4298
4299        // Adding excerpts emits an edited event.
4300        assert_eq!(
4301            events.read().as_slice(),
4302            &[
4303                Event::Edited {
4304                    singleton_buffer_edited: false
4305                },
4306                Event::Edited {
4307                    singleton_buffer_edited: false
4308                },
4309                Event::Edited {
4310                    singleton_buffer_edited: false
4311                }
4312            ]
4313        );
4314
4315        let snapshot = multibuffer.read(cx).snapshot(cx);
4316        assert_eq!(
4317            snapshot.text(),
4318            concat!(
4319                "bbbb\n",  // Preserve newlines
4320                "ccccc\n", //
4321                "ddd\n",   //
4322                "eeee\n",  //
4323                "jj"       //
4324            )
4325        );
4326        assert_eq!(
4327            snapshot.buffer_rows(0).collect::<Vec<_>>(),
4328            [Some(1), Some(2), Some(3), Some(4), Some(3)]
4329        );
4330        assert_eq!(
4331            snapshot.buffer_rows(2).collect::<Vec<_>>(),
4332            [Some(3), Some(4), Some(3)]
4333        );
4334        assert_eq!(snapshot.buffer_rows(4).collect::<Vec<_>>(), [Some(3)]);
4335        assert_eq!(snapshot.buffer_rows(5).collect::<Vec<_>>(), []);
4336
4337        assert_eq!(
4338            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
4339            &[
4340                (0, "bbbb\nccccc".to_string(), true),
4341                (2, "ddd\neeee".to_string(), false),
4342                (4, "jj".to_string(), true),
4343            ]
4344        );
4345        assert_eq!(
4346            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
4347            &[(0, "bbbb\nccccc".to_string(), true)]
4348        );
4349        assert_eq!(
4350            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
4351            &[]
4352        );
4353        assert_eq!(
4354            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
4355            &[]
4356        );
4357        assert_eq!(
4358            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4359            &[(2, "ddd\neeee".to_string(), false)]
4360        );
4361        assert_eq!(
4362            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
4363            &[(2, "ddd\neeee".to_string(), false)]
4364        );
4365        assert_eq!(
4366            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
4367            &[(2, "ddd\neeee".to_string(), false)]
4368        );
4369        assert_eq!(
4370            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
4371            &[(4, "jj".to_string(), true)]
4372        );
4373        assert_eq!(
4374            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
4375            &[]
4376        );
4377
4378        buffer_1.update(cx, |buffer, cx| {
4379            let text = "\n";
4380            buffer.edit(
4381                [
4382                    (Point::new(0, 0)..Point::new(0, 0), text),
4383                    (Point::new(2, 1)..Point::new(2, 3), text),
4384                ],
4385                None,
4386                cx,
4387            );
4388        });
4389
4390        let snapshot = multibuffer.read(cx).snapshot(cx);
4391        assert_eq!(
4392            snapshot.text(),
4393            concat!(
4394                "bbbb\n", // Preserve newlines
4395                "c\n",    //
4396                "cc\n",   //
4397                "ddd\n",  //
4398                "eeee\n", //
4399                "jj"      //
4400            )
4401        );
4402
4403        assert_eq!(
4404            subscription.consume().into_inner(),
4405            [Edit {
4406                old: 6..8,
4407                new: 6..7
4408            }]
4409        );
4410
4411        let snapshot = multibuffer.read(cx).snapshot(cx);
4412        assert_eq!(
4413            snapshot.clip_point(Point::new(0, 5), Bias::Left),
4414            Point::new(0, 4)
4415        );
4416        assert_eq!(
4417            snapshot.clip_point(Point::new(0, 5), Bias::Right),
4418            Point::new(0, 4)
4419        );
4420        assert_eq!(
4421            snapshot.clip_point(Point::new(5, 1), Bias::Right),
4422            Point::new(5, 1)
4423        );
4424        assert_eq!(
4425            snapshot.clip_point(Point::new(5, 2), Bias::Right),
4426            Point::new(5, 2)
4427        );
4428        assert_eq!(
4429            snapshot.clip_point(Point::new(5, 3), Bias::Right),
4430            Point::new(5, 2)
4431        );
4432
4433        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
4434            let (buffer_2_excerpt_id, _) =
4435                multibuffer.excerpts_for_buffer(&buffer_2, cx)[0].clone();
4436            multibuffer.remove_excerpts([buffer_2_excerpt_id], cx);
4437            multibuffer.snapshot(cx)
4438        });
4439
4440        assert_eq!(
4441            snapshot.text(),
4442            concat!(
4443                "bbbb\n", // Preserve newlines
4444                "c\n",    //
4445                "cc\n",   //
4446                "ddd\n",  //
4447                "eeee",   //
4448            )
4449        );
4450
4451        fn boundaries_in_range(
4452            range: Range<Point>,
4453            snapshot: &MultiBufferSnapshot,
4454        ) -> Vec<(u32, String, bool)> {
4455            snapshot
4456                .excerpt_boundaries_in_range(range)
4457                .map(|boundary| {
4458                    (
4459                        boundary.row,
4460                        boundary
4461                            .buffer
4462                            .text_for_range(boundary.range.context)
4463                            .collect::<String>(),
4464                        boundary.starts_new_buffer,
4465                    )
4466                })
4467                .collect::<Vec<_>>()
4468        }
4469    }
4470
4471    #[gpui::test]
4472    fn test_excerpt_events(cx: &mut AppContext) {
4473        let buffer_1 = cx.new_model(|cx| {
4474            Buffer::new(
4475                0,
4476                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4477                sample_text(10, 3, 'a'),
4478            )
4479        });
4480        let buffer_2 = cx.new_model(|cx| {
4481            Buffer::new(
4482                0,
4483                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4484                sample_text(10, 3, 'm'),
4485            )
4486        });
4487
4488        let leader_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4489        let follower_multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4490        let follower_edit_event_count = Arc::new(RwLock::new(0));
4491
4492        follower_multibuffer.update(cx, |_, cx| {
4493            let follower_edit_event_count = follower_edit_event_count.clone();
4494            cx.subscribe(
4495                &leader_multibuffer,
4496                move |follower, _, event, cx| match event.clone() {
4497                    Event::ExcerptsAdded {
4498                        buffer,
4499                        predecessor,
4500                        excerpts,
4501                    } => follower.insert_excerpts_with_ids_after(predecessor, buffer, excerpts, cx),
4502                    Event::ExcerptsRemoved { ids } => follower.remove_excerpts(ids, cx),
4503                    Event::Edited { .. } => {
4504                        *follower_edit_event_count.write() += 1;
4505                    }
4506                    _ => {}
4507                },
4508            )
4509            .detach();
4510        });
4511
4512        leader_multibuffer.update(cx, |leader, cx| {
4513            leader.push_excerpts(
4514                buffer_1.clone(),
4515                [
4516                    ExcerptRange {
4517                        context: 0..8,
4518                        primary: None,
4519                    },
4520                    ExcerptRange {
4521                        context: 12..16,
4522                        primary: None,
4523                    },
4524                ],
4525                cx,
4526            );
4527            leader.insert_excerpts_after(
4528                leader.excerpt_ids()[0],
4529                buffer_2.clone(),
4530                [
4531                    ExcerptRange {
4532                        context: 0..5,
4533                        primary: None,
4534                    },
4535                    ExcerptRange {
4536                        context: 10..15,
4537                        primary: None,
4538                    },
4539                ],
4540                cx,
4541            )
4542        });
4543        assert_eq!(
4544            leader_multibuffer.read(cx).snapshot(cx).text(),
4545            follower_multibuffer.read(cx).snapshot(cx).text(),
4546        );
4547        assert_eq!(*follower_edit_event_count.read(), 2);
4548
4549        leader_multibuffer.update(cx, |leader, cx| {
4550            let excerpt_ids = leader.excerpt_ids();
4551            leader.remove_excerpts([excerpt_ids[1], excerpt_ids[3]], cx);
4552        });
4553        assert_eq!(
4554            leader_multibuffer.read(cx).snapshot(cx).text(),
4555            follower_multibuffer.read(cx).snapshot(cx).text(),
4556        );
4557        assert_eq!(*follower_edit_event_count.read(), 3);
4558
4559        // Removing an empty set of excerpts is a noop.
4560        leader_multibuffer.update(cx, |leader, cx| {
4561            leader.remove_excerpts([], cx);
4562        });
4563        assert_eq!(
4564            leader_multibuffer.read(cx).snapshot(cx).text(),
4565            follower_multibuffer.read(cx).snapshot(cx).text(),
4566        );
4567        assert_eq!(*follower_edit_event_count.read(), 3);
4568
4569        // Adding an empty set of excerpts is a noop.
4570        leader_multibuffer.update(cx, |leader, cx| {
4571            leader.push_excerpts::<usize>(buffer_2.clone(), [], cx);
4572        });
4573        assert_eq!(
4574            leader_multibuffer.read(cx).snapshot(cx).text(),
4575            follower_multibuffer.read(cx).snapshot(cx).text(),
4576        );
4577        assert_eq!(*follower_edit_event_count.read(), 3);
4578
4579        leader_multibuffer.update(cx, |leader, cx| {
4580            leader.clear(cx);
4581        });
4582        assert_eq!(
4583            leader_multibuffer.read(cx).snapshot(cx).text(),
4584            follower_multibuffer.read(cx).snapshot(cx).text(),
4585        );
4586        assert_eq!(*follower_edit_event_count.read(), 4);
4587    }
4588
4589    #[gpui::test]
4590    fn test_push_excerpts_with_context_lines(cx: &mut AppContext) {
4591        let buffer = cx.new_model(|cx| {
4592            Buffer::new(
4593                0,
4594                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4595                sample_text(20, 3, 'a'),
4596            )
4597        });
4598        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4599        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
4600            multibuffer.push_excerpts_with_context_lines(
4601                buffer.clone(),
4602                vec![
4603                    Point::new(3, 2)..Point::new(4, 2),
4604                    Point::new(7, 1)..Point::new(7, 3),
4605                    Point::new(15, 0)..Point::new(15, 0),
4606                ],
4607                2,
4608                cx,
4609            )
4610        });
4611
4612        let snapshot = multibuffer.read(cx).snapshot(cx);
4613        assert_eq!(
4614            snapshot.text(),
4615            "bbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\n\nnnn\nooo\nppp\nqqq\nrrr\n"
4616        );
4617
4618        assert_eq!(
4619            anchor_ranges
4620                .iter()
4621                .map(|range| range.to_point(&snapshot))
4622                .collect::<Vec<_>>(),
4623            vec![
4624                Point::new(2, 2)..Point::new(3, 2),
4625                Point::new(6, 1)..Point::new(6, 3),
4626                Point::new(12, 0)..Point::new(12, 0)
4627            ]
4628        );
4629    }
4630
4631    #[gpui::test]
4632    async fn test_stream_excerpts_with_context_lines(cx: &mut TestAppContext) {
4633        let buffer = cx.new_model(|cx| {
4634            Buffer::new(
4635                0,
4636                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4637                sample_text(20, 3, 'a'),
4638            )
4639        });
4640        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4641        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
4642            let snapshot = buffer.read(cx);
4643            let ranges = vec![
4644                snapshot.anchor_before(Point::new(3, 2))..snapshot.anchor_before(Point::new(4, 2)),
4645                snapshot.anchor_before(Point::new(7, 1))..snapshot.anchor_before(Point::new(7, 3)),
4646                snapshot.anchor_before(Point::new(15, 0))
4647                    ..snapshot.anchor_before(Point::new(15, 0)),
4648            ];
4649            multibuffer.stream_excerpts_with_context_lines(buffer.clone(), ranges, 2, cx)
4650        });
4651
4652        let anchor_ranges = anchor_ranges.collect::<Vec<_>>().await;
4653
4654        let snapshot = multibuffer.update(cx, |multibuffer, cx| multibuffer.snapshot(cx));
4655        assert_eq!(
4656            snapshot.text(),
4657            "bbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\n\nnnn\nooo\nppp\nqqq\nrrr\n"
4658        );
4659
4660        assert_eq!(
4661            anchor_ranges
4662                .iter()
4663                .map(|range| range.to_point(&snapshot))
4664                .collect::<Vec<_>>(),
4665            vec![
4666                Point::new(2, 2)..Point::new(3, 2),
4667                Point::new(6, 1)..Point::new(6, 3),
4668                Point::new(12, 0)..Point::new(12, 0)
4669            ]
4670        );
4671    }
4672
4673    #[gpui::test]
4674    fn test_empty_multibuffer(cx: &mut AppContext) {
4675        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4676
4677        let snapshot = multibuffer.read(cx).snapshot(cx);
4678        assert_eq!(snapshot.text(), "");
4679        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), &[Some(0)]);
4680        assert_eq!(snapshot.buffer_rows(1).collect::<Vec<_>>(), &[]);
4681    }
4682
4683    #[gpui::test]
4684    fn test_singleton_multibuffer_anchors(cx: &mut AppContext) {
4685        let buffer = cx.new_model(|cx| {
4686            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "abcd")
4687        });
4688        let multibuffer = cx.new_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
4689        let old_snapshot = multibuffer.read(cx).snapshot(cx);
4690        buffer.update(cx, |buffer, cx| {
4691            buffer.edit([(0..0, "X")], None, cx);
4692            buffer.edit([(5..5, "Y")], None, cx);
4693        });
4694        let new_snapshot = multibuffer.read(cx).snapshot(cx);
4695
4696        assert_eq!(old_snapshot.text(), "abcd");
4697        assert_eq!(new_snapshot.text(), "XabcdY");
4698
4699        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
4700        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
4701        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
4702        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
4703    }
4704
4705    #[gpui::test]
4706    fn test_multibuffer_anchors(cx: &mut AppContext) {
4707        let buffer_1 = cx.new_model(|cx| {
4708            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "abcd")
4709        });
4710        let buffer_2 = cx.new_model(|cx| {
4711            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "efghi")
4712        });
4713        let multibuffer = cx.new_model(|cx| {
4714            let mut multibuffer = MultiBuffer::new(0, Capability::ReadWrite);
4715            multibuffer.push_excerpts(
4716                buffer_1.clone(),
4717                [ExcerptRange {
4718                    context: 0..4,
4719                    primary: None,
4720                }],
4721                cx,
4722            );
4723            multibuffer.push_excerpts(
4724                buffer_2.clone(),
4725                [ExcerptRange {
4726                    context: 0..5,
4727                    primary: None,
4728                }],
4729                cx,
4730            );
4731            multibuffer
4732        });
4733        let old_snapshot = multibuffer.read(cx).snapshot(cx);
4734
4735        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
4736        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
4737        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
4738        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
4739        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
4740        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
4741
4742        buffer_1.update(cx, |buffer, cx| {
4743            buffer.edit([(0..0, "W")], None, cx);
4744            buffer.edit([(5..5, "X")], None, cx);
4745        });
4746        buffer_2.update(cx, |buffer, cx| {
4747            buffer.edit([(0..0, "Y")], None, cx);
4748            buffer.edit([(6..6, "Z")], None, cx);
4749        });
4750        let new_snapshot = multibuffer.read(cx).snapshot(cx);
4751
4752        assert_eq!(old_snapshot.text(), "abcd\nefghi");
4753        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
4754
4755        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
4756        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
4757        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
4758        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
4759        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
4760        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
4761        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
4762        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
4763        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
4764        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
4765    }
4766
4767    #[gpui::test]
4768    fn test_resolving_anchors_after_replacing_their_excerpts(cx: &mut AppContext) {
4769        let buffer_1 = cx.new_model(|cx| {
4770            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "abcd")
4771        });
4772        let buffer_2 = cx.new_model(|cx| {
4773            Buffer::new(
4774                0,
4775                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4776                "ABCDEFGHIJKLMNOP",
4777            )
4778        });
4779        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4780
4781        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
4782        // Add an excerpt from buffer 1 that spans this new insertion.
4783        buffer_1.update(cx, |buffer, cx| buffer.edit([(4..4, "123")], None, cx));
4784        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
4785            multibuffer
4786                .push_excerpts(
4787                    buffer_1.clone(),
4788                    [ExcerptRange {
4789                        context: 0..7,
4790                        primary: None,
4791                    }],
4792                    cx,
4793                )
4794                .pop()
4795                .unwrap()
4796        });
4797
4798        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
4799        assert_eq!(snapshot_1.text(), "abcd123");
4800
4801        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
4802        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
4803            multibuffer.remove_excerpts([excerpt_id_1], cx);
4804            let mut ids = multibuffer
4805                .push_excerpts(
4806                    buffer_2.clone(),
4807                    [
4808                        ExcerptRange {
4809                            context: 0..4,
4810                            primary: None,
4811                        },
4812                        ExcerptRange {
4813                            context: 6..10,
4814                            primary: None,
4815                        },
4816                        ExcerptRange {
4817                            context: 12..16,
4818                            primary: None,
4819                        },
4820                    ],
4821                    cx,
4822                )
4823                .into_iter();
4824            (ids.next().unwrap(), ids.next().unwrap())
4825        });
4826        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
4827        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
4828
4829        // The old excerpt id doesn't get reused.
4830        assert_ne!(excerpt_id_2, excerpt_id_1);
4831
4832        // Resolve some anchors from the previous snapshot in the new snapshot.
4833        // The current excerpts are from a different buffer, so we don't attempt to
4834        // resolve the old text anchor in the new buffer.
4835        assert_eq!(
4836            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
4837            0
4838        );
4839        assert_eq!(
4840            snapshot_2.summaries_for_anchors::<usize, _>(&[
4841                snapshot_1.anchor_before(2),
4842                snapshot_1.anchor_after(3)
4843            ]),
4844            vec![0, 0]
4845        );
4846
4847        // Refresh anchors from the old snapshot. The return value indicates that both
4848        // anchors lost their original excerpt.
4849        let refresh =
4850            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
4851        assert_eq!(
4852            refresh,
4853            &[
4854                (0, snapshot_2.anchor_before(0), false),
4855                (1, snapshot_2.anchor_after(0), false),
4856            ]
4857        );
4858
4859        // Replace the middle excerpt with a smaller excerpt in buffer 2,
4860        // that intersects the old excerpt.
4861        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
4862            multibuffer.remove_excerpts([excerpt_id_3], cx);
4863            multibuffer
4864                .insert_excerpts_after(
4865                    excerpt_id_2,
4866                    buffer_2.clone(),
4867                    [ExcerptRange {
4868                        context: 5..8,
4869                        primary: None,
4870                    }],
4871                    cx,
4872                )
4873                .pop()
4874                .unwrap()
4875        });
4876
4877        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
4878        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
4879        assert_ne!(excerpt_id_5, excerpt_id_3);
4880
4881        // Resolve some anchors from the previous snapshot in the new snapshot.
4882        // The third anchor can't be resolved, since its excerpt has been removed,
4883        // so it resolves to the same position as its predecessor.
4884        let anchors = [
4885            snapshot_2.anchor_before(0),
4886            snapshot_2.anchor_after(2),
4887            snapshot_2.anchor_after(6),
4888            snapshot_2.anchor_after(14),
4889        ];
4890        assert_eq!(
4891            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
4892            &[0, 2, 9, 13]
4893        );
4894
4895        let new_anchors = snapshot_3.refresh_anchors(&anchors);
4896        assert_eq!(
4897            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
4898            &[(0, true), (1, true), (2, true), (3, true)]
4899        );
4900        assert_eq!(
4901            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
4902            &[0, 2, 7, 13]
4903        );
4904    }
4905
4906    #[gpui::test(iterations = 100)]
4907    fn test_random_multibuffer(cx: &mut AppContext, mut rng: StdRng) {
4908        let operations = env::var("OPERATIONS")
4909            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
4910            .unwrap_or(10);
4911
4912        let mut buffers: Vec<Model<Buffer>> = Vec::new();
4913        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
4914        let mut excerpt_ids = Vec::<ExcerptId>::new();
4915        let mut expected_excerpts = Vec::<(Model<Buffer>, Range<text::Anchor>)>::new();
4916        let mut anchors = Vec::new();
4917        let mut old_versions = Vec::new();
4918
4919        for _ in 0..operations {
4920            match rng.gen_range(0..100) {
4921                0..=19 if !buffers.is_empty() => {
4922                    let buffer = buffers.choose(&mut rng).unwrap();
4923                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
4924                }
4925                20..=29 if !expected_excerpts.is_empty() => {
4926                    let mut ids_to_remove = vec![];
4927                    for _ in 0..rng.gen_range(1..=3) {
4928                        if expected_excerpts.is_empty() {
4929                            break;
4930                        }
4931
4932                        let ix = rng.gen_range(0..expected_excerpts.len());
4933                        ids_to_remove.push(excerpt_ids.remove(ix));
4934                        let (buffer, range) = expected_excerpts.remove(ix);
4935                        let buffer = buffer.read(cx);
4936                        log::info!(
4937                            "Removing excerpt {}: {:?}",
4938                            ix,
4939                            buffer
4940                                .text_for_range(range.to_offset(buffer))
4941                                .collect::<String>(),
4942                        );
4943                    }
4944                    let snapshot = multibuffer.read(cx).read(cx);
4945                    ids_to_remove.sort_unstable_by(|a, b| a.cmp(&b, &snapshot));
4946                    drop(snapshot);
4947                    multibuffer.update(cx, |multibuffer, cx| {
4948                        multibuffer.remove_excerpts(ids_to_remove, cx)
4949                    });
4950                }
4951                30..=39 if !expected_excerpts.is_empty() => {
4952                    let multibuffer = multibuffer.read(cx).read(cx);
4953                    let offset =
4954                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
4955                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
4956                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
4957                    anchors.push(multibuffer.anchor_at(offset, bias));
4958                    anchors.sort_by(|a, b| a.cmp(b, &multibuffer));
4959                }
4960                40..=44 if !anchors.is_empty() => {
4961                    let multibuffer = multibuffer.read(cx).read(cx);
4962                    let prev_len = anchors.len();
4963                    anchors = multibuffer
4964                        .refresh_anchors(&anchors)
4965                        .into_iter()
4966                        .map(|a| a.1)
4967                        .collect();
4968
4969                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
4970                    // overshoot its boundaries.
4971                    assert_eq!(anchors.len(), prev_len);
4972                    for anchor in &anchors {
4973                        if anchor.excerpt_id == ExcerptId::min()
4974                            || anchor.excerpt_id == ExcerptId::max()
4975                        {
4976                            continue;
4977                        }
4978
4979                        let excerpt = multibuffer.excerpt(anchor.excerpt_id).unwrap();
4980                        assert_eq!(excerpt.id, anchor.excerpt_id);
4981                        assert!(excerpt.contains(anchor));
4982                    }
4983                }
4984                _ => {
4985                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
4986                        let base_text = util::RandomCharIter::new(&mut rng)
4987                            .take(10)
4988                            .collect::<String>();
4989                        buffers.push(cx.new_model(|cx| {
4990                            Buffer::new(
4991                                0,
4992                                BufferId::new(cx.entity_id().as_u64()).unwrap(),
4993                                base_text,
4994                            )
4995                        }));
4996                        buffers.last().unwrap()
4997                    } else {
4998                        buffers.choose(&mut rng).unwrap()
4999                    };
5000
5001                    let buffer = buffer_handle.read(cx);
5002                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
5003                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5004                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
5005                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
5006                    let prev_excerpt_id = excerpt_ids
5007                        .get(prev_excerpt_ix)
5008                        .cloned()
5009                        .unwrap_or_else(ExcerptId::max);
5010                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
5011
5012                    log::info!(
5013                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
5014                        excerpt_ix,
5015                        expected_excerpts.len(),
5016                        buffer_handle.read(cx).remote_id(),
5017                        buffer.text(),
5018                        start_ix..end_ix,
5019                        &buffer.text()[start_ix..end_ix]
5020                    );
5021
5022                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
5023                        multibuffer
5024                            .insert_excerpts_after(
5025                                prev_excerpt_id,
5026                                buffer_handle.clone(),
5027                                [ExcerptRange {
5028                                    context: start_ix..end_ix,
5029                                    primary: None,
5030                                }],
5031                                cx,
5032                            )
5033                            .pop()
5034                            .unwrap()
5035                    });
5036
5037                    excerpt_ids.insert(excerpt_ix, excerpt_id);
5038                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
5039                }
5040            }
5041
5042            if rng.gen_bool(0.3) {
5043                multibuffer.update(cx, |multibuffer, cx| {
5044                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
5045                })
5046            }
5047
5048            let snapshot = multibuffer.read(cx).snapshot(cx);
5049
5050            let mut excerpt_starts = Vec::new();
5051            let mut expected_text = String::new();
5052            let mut expected_buffer_rows = Vec::new();
5053            for (buffer, range) in &expected_excerpts {
5054                let buffer = buffer.read(cx);
5055                let buffer_range = range.to_offset(buffer);
5056
5057                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
5058                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
5059                expected_text.push('\n');
5060
5061                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
5062                    ..=buffer.offset_to_point(buffer_range.end).row;
5063                for row in buffer_row_range {
5064                    expected_buffer_rows.push(Some(row));
5065                }
5066            }
5067            // Remove final trailing newline.
5068            if !expected_excerpts.is_empty() {
5069                expected_text.pop();
5070            }
5071
5072            // Always report one buffer row
5073            if expected_buffer_rows.is_empty() {
5074                expected_buffer_rows.push(Some(0));
5075            }
5076
5077            assert_eq!(snapshot.text(), expected_text);
5078            log::info!("MultiBuffer text: {:?}", expected_text);
5079
5080            assert_eq!(
5081                snapshot.buffer_rows(0).collect::<Vec<_>>(),
5082                expected_buffer_rows,
5083            );
5084
5085            for _ in 0..5 {
5086                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
5087                assert_eq!(
5088                    snapshot.buffer_rows(start_row as u32).collect::<Vec<_>>(),
5089                    &expected_buffer_rows[start_row..],
5090                    "buffer_rows({})",
5091                    start_row
5092                );
5093            }
5094
5095            assert_eq!(
5096                snapshot.max_buffer_row(),
5097                expected_buffer_rows.into_iter().flatten().max().unwrap()
5098            );
5099
5100            let mut excerpt_starts = excerpt_starts.into_iter();
5101            for (buffer, range) in &expected_excerpts {
5102                let buffer = buffer.read(cx);
5103                let buffer_id = buffer.remote_id();
5104                let buffer_range = range.to_offset(buffer);
5105                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
5106                let buffer_start_point_utf16 =
5107                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
5108
5109                let excerpt_start = excerpt_starts.next().unwrap();
5110                let mut offset = excerpt_start.len;
5111                let mut buffer_offset = buffer_range.start;
5112                let mut point = excerpt_start.lines;
5113                let mut buffer_point = buffer_start_point;
5114                let mut point_utf16 = excerpt_start.lines_utf16();
5115                let mut buffer_point_utf16 = buffer_start_point_utf16;
5116                for ch in buffer
5117                    .snapshot()
5118                    .chunks(buffer_range.clone(), false)
5119                    .flat_map(|c| c.text.chars())
5120                {
5121                    for _ in 0..ch.len_utf8() {
5122                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
5123                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
5124                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
5125                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
5126                        assert_eq!(
5127                            left_offset,
5128                            excerpt_start.len + (buffer_left_offset - buffer_range.start),
5129                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
5130                            offset,
5131                            buffer_id,
5132                            buffer_offset,
5133                        );
5134                        assert_eq!(
5135                            right_offset,
5136                            excerpt_start.len + (buffer_right_offset - buffer_range.start),
5137                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
5138                            offset,
5139                            buffer_id,
5140                            buffer_offset,
5141                        );
5142
5143                        let left_point = snapshot.clip_point(point, Bias::Left);
5144                        let right_point = snapshot.clip_point(point, Bias::Right);
5145                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
5146                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
5147                        assert_eq!(
5148                            left_point,
5149                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
5150                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
5151                            point,
5152                            buffer_id,
5153                            buffer_point,
5154                        );
5155                        assert_eq!(
5156                            right_point,
5157                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
5158                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
5159                            point,
5160                            buffer_id,
5161                            buffer_point,
5162                        );
5163
5164                        assert_eq!(
5165                            snapshot.point_to_offset(left_point),
5166                            left_offset,
5167                            "point_to_offset({:?})",
5168                            left_point,
5169                        );
5170                        assert_eq!(
5171                            snapshot.offset_to_point(left_offset),
5172                            left_point,
5173                            "offset_to_point({:?})",
5174                            left_offset,
5175                        );
5176
5177                        offset += 1;
5178                        buffer_offset += 1;
5179                        if ch == '\n' {
5180                            point += Point::new(1, 0);
5181                            buffer_point += Point::new(1, 0);
5182                        } else {
5183                            point += Point::new(0, 1);
5184                            buffer_point += Point::new(0, 1);
5185                        }
5186                    }
5187
5188                    for _ in 0..ch.len_utf16() {
5189                        let left_point_utf16 =
5190                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Left);
5191                        let right_point_utf16 =
5192                            snapshot.clip_point_utf16(Unclipped(point_utf16), Bias::Right);
5193                        let buffer_left_point_utf16 =
5194                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Left);
5195                        let buffer_right_point_utf16 =
5196                            buffer.clip_point_utf16(Unclipped(buffer_point_utf16), Bias::Right);
5197                        assert_eq!(
5198                            left_point_utf16,
5199                            excerpt_start.lines_utf16()
5200                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
5201                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
5202                            point_utf16,
5203                            buffer_id,
5204                            buffer_point_utf16,
5205                        );
5206                        assert_eq!(
5207                            right_point_utf16,
5208                            excerpt_start.lines_utf16()
5209                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
5210                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
5211                            point_utf16,
5212                            buffer_id,
5213                            buffer_point_utf16,
5214                        );
5215
5216                        if ch == '\n' {
5217                            point_utf16 += PointUtf16::new(1, 0);
5218                            buffer_point_utf16 += PointUtf16::new(1, 0);
5219                        } else {
5220                            point_utf16 += PointUtf16::new(0, 1);
5221                            buffer_point_utf16 += PointUtf16::new(0, 1);
5222                        }
5223                    }
5224                }
5225            }
5226
5227            for (row, line) in expected_text.split('\n').enumerate() {
5228                assert_eq!(
5229                    snapshot.line_len(row as u32),
5230                    line.len() as u32,
5231                    "line_len({}).",
5232                    row
5233                );
5234            }
5235
5236            let text_rope = Rope::from(expected_text.as_str());
5237            for _ in 0..10 {
5238                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
5239                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
5240
5241                let text_for_range = snapshot
5242                    .text_for_range(start_ix..end_ix)
5243                    .collect::<String>();
5244                assert_eq!(
5245                    text_for_range,
5246                    &expected_text[start_ix..end_ix],
5247                    "incorrect text for range {:?}",
5248                    start_ix..end_ix
5249                );
5250
5251                let excerpted_buffer_ranges = multibuffer
5252                    .read(cx)
5253                    .range_to_buffer_ranges(start_ix..end_ix, cx);
5254                let excerpted_buffers_text = excerpted_buffer_ranges
5255                    .iter()
5256                    .map(|(buffer, buffer_range, _)| {
5257                        buffer
5258                            .read(cx)
5259                            .text_for_range(buffer_range.clone())
5260                            .collect::<String>()
5261                    })
5262                    .collect::<Vec<_>>()
5263                    .join("\n");
5264                assert_eq!(excerpted_buffers_text, text_for_range);
5265                if !expected_excerpts.is_empty() {
5266                    assert!(!excerpted_buffer_ranges.is_empty());
5267                }
5268
5269                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
5270                assert_eq!(
5271                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
5272                    expected_summary,
5273                    "incorrect summary for range {:?}",
5274                    start_ix..end_ix
5275                );
5276            }
5277
5278            // Anchor resolution
5279            let summaries = snapshot.summaries_for_anchors::<usize, _>(&anchors);
5280            assert_eq!(anchors.len(), summaries.len());
5281            for (anchor, resolved_offset) in anchors.iter().zip(summaries) {
5282                assert!(resolved_offset <= snapshot.len());
5283                assert_eq!(
5284                    snapshot.summary_for_anchor::<usize>(anchor),
5285                    resolved_offset
5286                );
5287            }
5288
5289            for _ in 0..10 {
5290                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
5291                assert_eq!(
5292                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
5293                    expected_text[..end_ix].chars().rev().collect::<String>(),
5294                );
5295            }
5296
5297            for _ in 0..10 {
5298                let end_ix = rng.gen_range(0..=text_rope.len());
5299                let start_ix = rng.gen_range(0..=end_ix);
5300                assert_eq!(
5301                    snapshot
5302                        .bytes_in_range(start_ix..end_ix)
5303                        .flatten()
5304                        .copied()
5305                        .collect::<Vec<_>>(),
5306                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
5307                    "bytes_in_range({:?})",
5308                    start_ix..end_ix,
5309                );
5310            }
5311        }
5312
5313        let snapshot = multibuffer.read(cx).snapshot(cx);
5314        for (old_snapshot, subscription) in old_versions {
5315            let edits = subscription.consume().into_inner();
5316
5317            log::info!(
5318                "applying subscription edits to old text: {:?}: {:?}",
5319                old_snapshot.text(),
5320                edits,
5321            );
5322
5323            let mut text = old_snapshot.text();
5324            for edit in edits {
5325                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
5326                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
5327            }
5328            assert_eq!(text.to_string(), snapshot.text());
5329        }
5330    }
5331
5332    #[gpui::test]
5333    fn test_history(cx: &mut AppContext) {
5334        let test_settings = SettingsStore::test(cx);
5335        cx.set_global(test_settings);
5336
5337        let buffer_1 = cx.new_model(|cx| {
5338            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "1234")
5339        });
5340        let buffer_2 = cx.new_model(|cx| {
5341            Buffer::new(0, BufferId::new(cx.entity_id().as_u64()).unwrap(), "5678")
5342        });
5343        let multibuffer = cx.new_model(|_| MultiBuffer::new(0, Capability::ReadWrite));
5344        let group_interval = multibuffer.read(cx).history.group_interval;
5345        multibuffer.update(cx, |multibuffer, cx| {
5346            multibuffer.push_excerpts(
5347                buffer_1.clone(),
5348                [ExcerptRange {
5349                    context: 0..buffer_1.read(cx).len(),
5350                    primary: None,
5351                }],
5352                cx,
5353            );
5354            multibuffer.push_excerpts(
5355                buffer_2.clone(),
5356                [ExcerptRange {
5357                    context: 0..buffer_2.read(cx).len(),
5358                    primary: None,
5359                }],
5360                cx,
5361            );
5362        });
5363
5364        let mut now = Instant::now();
5365
5366        multibuffer.update(cx, |multibuffer, cx| {
5367            let transaction_1 = multibuffer.start_transaction_at(now, cx).unwrap();
5368            multibuffer.edit(
5369                [
5370                    (Point::new(0, 0)..Point::new(0, 0), "A"),
5371                    (Point::new(1, 0)..Point::new(1, 0), "A"),
5372                ],
5373                None,
5374                cx,
5375            );
5376            multibuffer.edit(
5377                [
5378                    (Point::new(0, 1)..Point::new(0, 1), "B"),
5379                    (Point::new(1, 1)..Point::new(1, 1), "B"),
5380                ],
5381                None,
5382                cx,
5383            );
5384            multibuffer.end_transaction_at(now, cx);
5385            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5386
5387            // Edit buffer 1 through the multibuffer
5388            now += 2 * group_interval;
5389            multibuffer.start_transaction_at(now, cx);
5390            multibuffer.edit([(2..2, "C")], None, cx);
5391            multibuffer.end_transaction_at(now, cx);
5392            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
5393
5394            // Edit buffer 1 independently
5395            buffer_1.update(cx, |buffer_1, cx| {
5396                buffer_1.start_transaction_at(now);
5397                buffer_1.edit([(3..3, "D")], None, cx);
5398                buffer_1.end_transaction_at(now, cx);
5399
5400                now += 2 * group_interval;
5401                buffer_1.start_transaction_at(now);
5402                buffer_1.edit([(4..4, "E")], None, cx);
5403                buffer_1.end_transaction_at(now, cx);
5404            });
5405            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
5406
5407            // An undo in the multibuffer undoes the multibuffer transaction
5408            // and also any individual buffer edits that have occurred since
5409            // that transaction.
5410            multibuffer.undo(cx);
5411            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5412
5413            multibuffer.undo(cx);
5414            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5415
5416            multibuffer.redo(cx);
5417            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5418
5419            multibuffer.redo(cx);
5420            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
5421
5422            // Undo buffer 2 independently.
5423            buffer_2.update(cx, |buffer_2, cx| buffer_2.undo(cx));
5424            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\n5678");
5425
5426            // An undo in the multibuffer undoes the components of the
5427            // the last multibuffer transaction that are not already undone.
5428            multibuffer.undo(cx);
5429            assert_eq!(multibuffer.read(cx).text(), "AB1234\n5678");
5430
5431            multibuffer.undo(cx);
5432            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5433
5434            multibuffer.redo(cx);
5435            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
5436
5437            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
5438            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
5439
5440            // Redo stack gets cleared after an edit.
5441            now += 2 * group_interval;
5442            multibuffer.start_transaction_at(now, cx);
5443            multibuffer.edit([(0..0, "X")], None, cx);
5444            multibuffer.end_transaction_at(now, cx);
5445            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5446            multibuffer.redo(cx);
5447            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5448            multibuffer.undo(cx);
5449            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
5450            multibuffer.undo(cx);
5451            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5452
5453            // Transactions can be grouped manually.
5454            multibuffer.redo(cx);
5455            multibuffer.redo(cx);
5456            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5457            multibuffer.group_until_transaction(transaction_1, cx);
5458            multibuffer.undo(cx);
5459            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
5460            multibuffer.redo(cx);
5461            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
5462        });
5463    }
5464}