multi_buffer.rs

   1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt};
   4use anyhow::Result;
   5use clock::ReplicaId;
   6use collections::{HashMap, HashSet};
   7use gpui::{AppContext, Entity, ModelContext, ModelHandle, Task};
   8use language::{
   9    Buffer, BufferChunks, BufferSnapshot, Chunk, DiagnosticEntry, Event, File, Language, Outline,
  10    OutlineItem, Selection, ToOffset as _, ToPoint as _, TransactionId,
  11};
  12use std::{
  13    cell::{Ref, RefCell},
  14    cmp, fmt, io,
  15    iter::{self, FromIterator},
  16    ops::{Range, Sub},
  17    str,
  18    sync::Arc,
  19    time::{Duration, Instant},
  20};
  21use sum_tree::{Bias, Cursor, SumTree};
  22use text::{
  23    locator::Locator,
  24    rope::TextDimension,
  25    subscription::{Subscription, Topic},
  26    AnchorRangeExt as _, Edit, Point, PointUtf16, TextSummary,
  27};
  28use theme::SyntaxTheme;
  29use util::post_inc;
  30
  31const NEWLINES: &'static [u8] = &[b'\n'; u8::MAX as usize];
  32
  33pub type ExcerptId = Locator;
  34
  35pub struct MultiBuffer {
  36    snapshot: RefCell<MultiBufferSnapshot>,
  37    buffers: RefCell<HashMap<usize, BufferState>>,
  38    subscriptions: Topic,
  39    singleton: bool,
  40    replica_id: ReplicaId,
  41    history: History,
  42}
  43
  44struct History {
  45    next_transaction_id: usize,
  46    undo_stack: Vec<Transaction>,
  47    redo_stack: Vec<Transaction>,
  48    transaction_depth: usize,
  49    group_interval: Duration,
  50}
  51
  52struct Transaction {
  53    id: usize,
  54    buffer_transactions: HashSet<(usize, text::TransactionId)>,
  55    first_edit_at: Instant,
  56    last_edit_at: Instant,
  57}
  58
  59pub trait ToOffset: 'static + fmt::Debug {
  60    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
  61}
  62
  63pub trait ToPoint: 'static + fmt::Debug {
  64    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
  65}
  66
  67struct BufferState {
  68    buffer: ModelHandle<Buffer>,
  69    last_version: clock::Global,
  70    last_parse_count: usize,
  71    last_selections_update_count: usize,
  72    last_diagnostics_update_count: usize,
  73    excerpts: Vec<ExcerptId>,
  74    _subscriptions: [gpui::Subscription; 2],
  75}
  76
  77#[derive(Clone, Default)]
  78pub struct MultiBufferSnapshot {
  79    excerpts: SumTree<Excerpt>,
  80    parse_count: usize,
  81    diagnostics_update_count: usize,
  82    is_dirty: bool,
  83    has_conflict: bool,
  84}
  85
  86pub struct ExcerptProperties<'a, T> {
  87    pub buffer: &'a ModelHandle<Buffer>,
  88    pub range: Range<T>,
  89}
  90
  91#[derive(Clone)]
  92struct Excerpt {
  93    id: ExcerptId,
  94    buffer_id: usize,
  95    buffer: BufferSnapshot,
  96    range: Range<text::Anchor>,
  97    max_buffer_row: u32,
  98    text_summary: TextSummary,
  99    has_trailing_newline: bool,
 100}
 101
 102#[derive(Clone, Debug, Default)]
 103struct ExcerptSummary {
 104    excerpt_id: ExcerptId,
 105    max_buffer_row: u32,
 106    text: TextSummary,
 107}
 108
 109pub struct MultiBufferRows<'a> {
 110    buffer_row_range: Range<u32>,
 111    excerpts: Cursor<'a, Excerpt, Point>,
 112}
 113
 114pub struct MultiBufferChunks<'a> {
 115    range: Range<usize>,
 116    excerpts: Cursor<'a, Excerpt, usize>,
 117    excerpt_chunks: Option<ExcerptChunks<'a>>,
 118    theme: Option<&'a SyntaxTheme>,
 119}
 120
 121pub struct MultiBufferBytes<'a> {
 122    range: Range<usize>,
 123    excerpts: Cursor<'a, Excerpt, usize>,
 124    excerpt_bytes: Option<ExcerptBytes<'a>>,
 125    chunk: &'a [u8],
 126}
 127
 128struct ExcerptChunks<'a> {
 129    content_chunks: BufferChunks<'a>,
 130    footer_height: usize,
 131}
 132
 133struct ExcerptBytes<'a> {
 134    content_bytes: language::rope::Bytes<'a>,
 135    footer_height: usize,
 136}
 137
 138impl MultiBuffer {
 139    pub fn new(replica_id: ReplicaId) -> Self {
 140        Self {
 141            snapshot: Default::default(),
 142            buffers: Default::default(),
 143            subscriptions: Default::default(),
 144            singleton: false,
 145            replica_id,
 146            history: History {
 147                next_transaction_id: Default::default(),
 148                undo_stack: Default::default(),
 149                redo_stack: Default::default(),
 150                transaction_depth: 0,
 151                group_interval: Duration::from_millis(300),
 152            },
 153        }
 154    }
 155
 156    pub fn singleton(buffer: ModelHandle<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 157        let mut this = Self::new(buffer.read(cx).replica_id());
 158        this.singleton = true;
 159        this.push_excerpt(
 160            ExcerptProperties {
 161                buffer: &buffer,
 162                range: text::Anchor::min()..text::Anchor::max(),
 163            },
 164            cx,
 165        );
 166        this
 167    }
 168
 169    #[cfg(any(test, feature = "test-support"))]
 170    pub fn build_simple(text: &str, cx: &mut gpui::MutableAppContext) -> ModelHandle<Self> {
 171        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
 172        cx.add_model(|cx| Self::singleton(buffer, cx))
 173    }
 174
 175    #[cfg(any(test, feature = "test-support"))]
 176    pub fn build_random(
 177        mut rng: &mut impl rand::Rng,
 178        cx: &mut gpui::MutableAppContext,
 179    ) -> ModelHandle<Self> {
 180        use rand::prelude::*;
 181        use std::env;
 182        use text::RandomCharIter;
 183
 184        let max_excerpts = env::var("MAX_EXCERPTS")
 185            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
 186            .unwrap_or(5);
 187        let excerpts = rng.gen_range(1..=max_excerpts);
 188
 189        cx.add_model(|cx| {
 190            let mut multibuffer = MultiBuffer::new(0);
 191            let mut buffers = Vec::new();
 192            for _ in 0..excerpts {
 193                let buffer_handle = if rng.gen() || buffers.is_empty() {
 194                    let text = RandomCharIter::new(&mut rng).take(10).collect::<String>();
 195                    buffers.push(cx.add_model(|cx| Buffer::new(0, text, cx)));
 196                    let buffer = buffers.last().unwrap();
 197                    log::info!(
 198                        "Creating new buffer {} with text: {:?}",
 199                        buffer.id(),
 200                        buffer.read(cx).text()
 201                    );
 202                    buffers.last().unwrap()
 203                } else {
 204                    buffers.choose(rng).unwrap()
 205                };
 206
 207                let buffer = buffer_handle.read(cx);
 208                let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
 209                let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
 210                let header_height = rng.gen_range(0..=5);
 211                log::info!(
 212                    "Inserting excerpt from buffer {} with header height {} and range {:?}: {:?}",
 213                    buffer_handle.id(),
 214                    header_height,
 215                    start_ix..end_ix,
 216                    &buffer.text()[start_ix..end_ix]
 217                );
 218
 219                multibuffer.push_excerpt(
 220                    ExcerptProperties {
 221                        buffer: buffer_handle,
 222                        range: start_ix..end_ix,
 223                    },
 224                    cx,
 225                );
 226            }
 227            multibuffer
 228        })
 229    }
 230
 231    pub fn replica_id(&self) -> ReplicaId {
 232        self.replica_id
 233    }
 234
 235    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 236        self.sync(cx);
 237        self.snapshot.borrow().clone()
 238    }
 239
 240    pub fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 241        self.sync(cx);
 242        self.snapshot.borrow()
 243    }
 244
 245    pub fn as_singleton(&self) -> Option<ModelHandle<Buffer>> {
 246        if self.singleton {
 247            return Some(
 248                self.buffers
 249                    .borrow()
 250                    .values()
 251                    .next()
 252                    .unwrap()
 253                    .buffer
 254                    .clone(),
 255            );
 256        } else {
 257            None
 258        }
 259    }
 260
 261    pub fn subscribe(&mut self) -> Subscription {
 262        self.subscriptions.subscribe()
 263    }
 264
 265    pub fn edit<I, S, T>(&mut self, ranges: I, new_text: T, cx: &mut ModelContext<Self>)
 266    where
 267        I: IntoIterator<Item = Range<S>>,
 268        S: ToOffset,
 269        T: Into<String>,
 270    {
 271        self.edit_internal(ranges, new_text, false, cx)
 272    }
 273
 274    pub fn edit_with_autoindent<I, S, T>(
 275        &mut self,
 276        ranges: I,
 277        new_text: T,
 278        cx: &mut ModelContext<Self>,
 279    ) where
 280        I: IntoIterator<Item = Range<S>>,
 281        S: ToOffset,
 282        T: Into<String>,
 283    {
 284        self.edit_internal(ranges, new_text, true, cx)
 285    }
 286
 287    pub fn edit_internal<I, S, T>(
 288        &mut self,
 289        ranges_iter: I,
 290        new_text: T,
 291        autoindent: bool,
 292        cx: &mut ModelContext<Self>,
 293    ) where
 294        I: IntoIterator<Item = Range<S>>,
 295        S: ToOffset,
 296        T: Into<String>,
 297    {
 298        if let Some(buffer) = self.as_singleton() {
 299            let snapshot = self.read(cx);
 300            let ranges = ranges_iter
 301                .into_iter()
 302                .map(|range| range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot));
 303            return buffer.update(cx, |buffer, cx| {
 304                if autoindent {
 305                    buffer.edit_with_autoindent(ranges, new_text, cx)
 306                } else {
 307                    buffer.edit(ranges, new_text, cx)
 308                }
 309            });
 310        }
 311
 312        let snapshot = self.read(cx);
 313        let mut buffer_edits: HashMap<usize, Vec<(Range<usize>, bool)>> = Default::default();
 314        let mut cursor = snapshot.excerpts.cursor::<usize>();
 315        for range in ranges_iter {
 316            let start = range.start.to_offset(&snapshot);
 317            let end = range.end.to_offset(&snapshot);
 318            cursor.seek(&start, Bias::Right, &());
 319            if cursor.item().is_none() && start == *cursor.start() {
 320                cursor.prev(&());
 321            }
 322            let start_excerpt = cursor.item().expect("start offset out of bounds");
 323            let start_overshoot = start - cursor.start();
 324            let buffer_start =
 325                start_excerpt.range.start.to_offset(&start_excerpt.buffer) + start_overshoot;
 326
 327            cursor.seek(&end, Bias::Right, &());
 328            if cursor.item().is_none() && end == *cursor.start() {
 329                cursor.prev(&());
 330            }
 331            let end_excerpt = cursor.item().expect("end offset out of bounds");
 332            let end_overshoot = end - cursor.start();
 333            let buffer_end = end_excerpt.range.start.to_offset(&end_excerpt.buffer) + end_overshoot;
 334
 335            if start_excerpt.id == end_excerpt.id {
 336                buffer_edits
 337                    .entry(start_excerpt.buffer_id)
 338                    .or_insert(Vec::new())
 339                    .push((buffer_start..buffer_end, true));
 340            } else {
 341                let start_excerpt_range =
 342                    buffer_start..start_excerpt.range.end.to_offset(&start_excerpt.buffer);
 343                let end_excerpt_range =
 344                    end_excerpt.range.start.to_offset(&end_excerpt.buffer)..buffer_end;
 345                buffer_edits
 346                    .entry(start_excerpt.buffer_id)
 347                    .or_insert(Vec::new())
 348                    .push((start_excerpt_range, true));
 349                buffer_edits
 350                    .entry(end_excerpt.buffer_id)
 351                    .or_insert(Vec::new())
 352                    .push((end_excerpt_range, false));
 353
 354                cursor.seek(&start, Bias::Right, &());
 355                cursor.next(&());
 356                while let Some(excerpt) = cursor.item() {
 357                    if excerpt.id == end_excerpt.id {
 358                        break;
 359                    }
 360                    buffer_edits
 361                        .entry(excerpt.buffer_id)
 362                        .or_insert(Vec::new())
 363                        .push((excerpt.range.to_offset(&excerpt.buffer), false));
 364                    cursor.next(&());
 365                }
 366            }
 367        }
 368
 369        let new_text = new_text.into();
 370        for (buffer_id, mut edits) in buffer_edits {
 371            edits.sort_unstable_by_key(|(range, _)| range.start);
 372            self.buffers.borrow()[&buffer_id]
 373                .buffer
 374                .update(cx, |buffer, cx| {
 375                    let mut edits = edits.into_iter().peekable();
 376                    let mut insertions = Vec::new();
 377                    let mut deletions = Vec::new();
 378                    while let Some((mut range, mut is_insertion)) = edits.next() {
 379                        while let Some((next_range, next_is_insertion)) = edits.peek() {
 380                            if range.end >= next_range.start {
 381                                range.end = cmp::max(next_range.end, range.end);
 382                                is_insertion |= *next_is_insertion;
 383                                edits.next();
 384                            } else {
 385                                break;
 386                            }
 387                        }
 388
 389                        if is_insertion {
 390                            insertions.push(
 391                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 392                            );
 393                        } else if !range.is_empty() {
 394                            deletions.push(
 395                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 396                            );
 397                        }
 398                    }
 399
 400                    if autoindent {
 401                        buffer.edit_with_autoindent(deletions, "", cx);
 402                        buffer.edit_with_autoindent(insertions, new_text.clone(), cx);
 403                    } else {
 404                        buffer.edit(deletions, "", cx);
 405                        buffer.edit(insertions, new_text.clone(), cx);
 406                    }
 407                })
 408        }
 409    }
 410
 411    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 412        self.start_transaction_at(Instant::now(), cx)
 413    }
 414
 415    pub(crate) fn start_transaction_at(
 416        &mut self,
 417        now: Instant,
 418        cx: &mut ModelContext<Self>,
 419    ) -> Option<TransactionId> {
 420        if let Some(buffer) = self.as_singleton() {
 421            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 422        }
 423
 424        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 425            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 426        }
 427        self.history.start_transaction(now)
 428    }
 429
 430    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 431        self.end_transaction_at(Instant::now(), cx)
 432    }
 433
 434    pub(crate) fn end_transaction_at(
 435        &mut self,
 436        now: Instant,
 437        cx: &mut ModelContext<Self>,
 438    ) -> Option<TransactionId> {
 439        if let Some(buffer) = self.as_singleton() {
 440            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 441        }
 442
 443        let mut buffer_transactions = HashSet::default();
 444        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 445            if let Some(transaction_id) =
 446                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 447            {
 448                buffer_transactions.insert((buffer.id(), transaction_id));
 449            }
 450        }
 451
 452        if self.history.end_transaction(now, buffer_transactions) {
 453            let transaction_id = self.history.group().unwrap();
 454            Some(transaction_id)
 455        } else {
 456            None
 457        }
 458    }
 459
 460    pub fn set_active_selections(
 461        &mut self,
 462        selections: &[Selection<Anchor>],
 463        cx: &mut ModelContext<Self>,
 464    ) {
 465        let mut selections_by_buffer: HashMap<usize, Vec<Selection<text::Anchor>>> =
 466            Default::default();
 467        let snapshot = self.read(cx);
 468        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 469        for selection in selections {
 470            cursor.seek(&Some(&selection.start.excerpt_id), Bias::Left, &());
 471            while let Some(excerpt) = cursor.item() {
 472                if excerpt.id > selection.end.excerpt_id {
 473                    break;
 474                }
 475
 476                let mut start = excerpt.range.start.clone();
 477                let mut end = excerpt.range.end.clone();
 478                if excerpt.id == selection.start.excerpt_id {
 479                    start = selection.start.text_anchor.clone();
 480                }
 481                if excerpt.id == selection.end.excerpt_id {
 482                    end = selection.end.text_anchor.clone();
 483                }
 484                selections_by_buffer
 485                    .entry(excerpt.buffer_id)
 486                    .or_default()
 487                    .push(Selection {
 488                        id: selection.id,
 489                        start,
 490                        end,
 491                        reversed: selection.reversed,
 492                        goal: selection.goal,
 493                    });
 494
 495                cursor.next(&());
 496            }
 497        }
 498
 499        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 500            if !selections_by_buffer.contains_key(buffer_id) {
 501                buffer_state
 502                    .buffer
 503                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 504            }
 505        }
 506
 507        for (buffer_id, mut selections) in selections_by_buffer {
 508            self.buffers.borrow()[&buffer_id]
 509                .buffer
 510                .update(cx, |buffer, cx| {
 511                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer).unwrap());
 512                    let mut selections = selections.into_iter().peekable();
 513                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 514                        let mut selection = selections.next()?;
 515                        while let Some(next_selection) = selections.peek() {
 516                            if selection
 517                                .end
 518                                .cmp(&next_selection.start, buffer)
 519                                .unwrap()
 520                                .is_ge()
 521                            {
 522                                let next_selection = selections.next().unwrap();
 523                                if next_selection
 524                                    .end
 525                                    .cmp(&selection.end, buffer)
 526                                    .unwrap()
 527                                    .is_ge()
 528                                {
 529                                    selection.end = next_selection.end;
 530                                }
 531                            } else {
 532                                break;
 533                            }
 534                        }
 535                        Some(selection)
 536                    }));
 537                    buffer.set_active_selections(merged_selections, cx);
 538                });
 539        }
 540    }
 541
 542    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
 543        for buffer in self.buffers.borrow().values() {
 544            buffer
 545                .buffer
 546                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 547        }
 548    }
 549
 550    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 551        if let Some(buffer) = self.as_singleton() {
 552            return buffer.update(cx, |buffer, cx| buffer.undo(cx));
 553        }
 554
 555        while let Some(transaction) = self.history.pop_undo() {
 556            let mut undone = false;
 557            for (buffer_id, buffer_transaction_id) in &transaction.buffer_transactions {
 558                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 559                    undone |= buffer.update(cx, |buf, cx| {
 560                        buf.undo_transaction(*buffer_transaction_id, cx)
 561                    });
 562                }
 563            }
 564
 565            if undone {
 566                return Some(transaction.id);
 567            }
 568        }
 569
 570        None
 571    }
 572
 573    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 574        if let Some(buffer) = self.as_singleton() {
 575            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
 576        }
 577
 578        while let Some(transaction) = self.history.pop_redo() {
 579            let mut redone = false;
 580            for (buffer_id, buffer_transaction_id) in &transaction.buffer_transactions {
 581                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 582                    redone |= buffer.update(cx, |buf, cx| {
 583                        buf.redo_transaction(*buffer_transaction_id, cx)
 584                    });
 585                }
 586            }
 587
 588            if redone {
 589                return Some(transaction.id);
 590            }
 591        }
 592
 593        None
 594    }
 595
 596    pub fn push_excerpt<O>(
 597        &mut self,
 598        props: ExcerptProperties<O>,
 599        cx: &mut ModelContext<Self>,
 600    ) -> ExcerptId
 601    where
 602        O: text::ToOffset,
 603    {
 604        self.insert_excerpt_after(&ExcerptId::max(), props, cx)
 605    }
 606
 607    pub fn insert_excerpt_after<O>(
 608        &mut self,
 609        prev_excerpt_id: &ExcerptId,
 610        props: ExcerptProperties<O>,
 611        cx: &mut ModelContext<Self>,
 612    ) -> ExcerptId
 613    where
 614        O: text::ToOffset,
 615    {
 616        assert_eq!(self.history.transaction_depth, 0);
 617        self.sync(cx);
 618
 619        let buffer_snapshot = props.buffer.read(cx).snapshot();
 620        let range = buffer_snapshot.anchor_before(&props.range.start)
 621            ..buffer_snapshot.anchor_after(&props.range.end);
 622        let mut snapshot = self.snapshot.borrow_mut();
 623        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 624        let mut new_excerpts = cursor.slice(&Some(prev_excerpt_id), Bias::Right, &());
 625
 626        let mut prev_id = ExcerptId::min();
 627        let edit_start = new_excerpts.summary().text.bytes;
 628        new_excerpts.update_last(
 629            |excerpt| {
 630                excerpt.has_trailing_newline = true;
 631                prev_id = excerpt.id.clone();
 632            },
 633            &(),
 634        );
 635
 636        let mut next_id = ExcerptId::max();
 637        if let Some(next_excerpt) = cursor.item() {
 638            next_id = next_excerpt.id.clone();
 639        }
 640
 641        let id = ExcerptId::between(&prev_id, &next_id);
 642
 643        let mut buffers = self.buffers.borrow_mut();
 644        let buffer_state = buffers
 645            .entry(props.buffer.id())
 646            .or_insert_with(|| BufferState {
 647                last_version: buffer_snapshot.version().clone(),
 648                last_parse_count: buffer_snapshot.parse_count(),
 649                last_selections_update_count: buffer_snapshot.selections_update_count(),
 650                last_diagnostics_update_count: buffer_snapshot.diagnostics_update_count(),
 651                excerpts: Default::default(),
 652                _subscriptions: [
 653                    cx.observe(&props.buffer, |_, _, cx| cx.notify()),
 654                    cx.subscribe(&props.buffer, Self::on_buffer_event),
 655                ],
 656                buffer: props.buffer.clone(),
 657            });
 658        if let Err(ix) = buffer_state.excerpts.binary_search(&id) {
 659            buffer_state.excerpts.insert(ix, id.clone());
 660        }
 661
 662        let excerpt = Excerpt::new(
 663            id.clone(),
 664            props.buffer.id(),
 665            buffer_snapshot,
 666            range,
 667            cursor.item().is_some(),
 668        );
 669        new_excerpts.push(excerpt, &());
 670        let edit_end = new_excerpts.summary().text.bytes;
 671
 672        new_excerpts.push_tree(cursor.suffix(&()), &());
 673        drop(cursor);
 674        snapshot.excerpts = new_excerpts;
 675
 676        self.subscriptions.publish_mut([Edit {
 677            old: edit_start..edit_start,
 678            new: edit_start..edit_end,
 679        }]);
 680
 681        cx.notify();
 682        id
 683    }
 684
 685    pub fn excerpt_ids_for_buffer(&self, buffer: &ModelHandle<Buffer>) -> Vec<ExcerptId> {
 686        self.buffers
 687            .borrow()
 688            .get(&buffer.id())
 689            .map_or(Vec::new(), |state| state.excerpts.clone())
 690    }
 691
 692    pub fn excerpted_buffers<'a, T: ToOffset>(
 693        &'a self,
 694        range: Range<T>,
 695        cx: &AppContext,
 696    ) -> Vec<(ModelHandle<Buffer>, Range<usize>)> {
 697        let snapshot = self.snapshot(cx);
 698        let start = range.start.to_offset(&snapshot);
 699        let end = range.end.to_offset(&snapshot);
 700
 701        let mut result = Vec::new();
 702        let mut cursor = snapshot.excerpts.cursor::<usize>();
 703        cursor.seek(&start, Bias::Right, &());
 704        while let Some(excerpt) = cursor.item() {
 705            if *cursor.start() > end {
 706                break;
 707            }
 708
 709            let mut end_before_newline = cursor.end(&());
 710            if excerpt.has_trailing_newline {
 711                end_before_newline -= 1;
 712            }
 713            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
 714            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
 715            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
 716            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
 717            result.push((buffer, start..end));
 718            cursor.next(&());
 719        }
 720
 721        result
 722    }
 723
 724    pub fn remove_excerpts<'a>(
 725        &mut self,
 726        excerpt_ids: impl IntoIterator<Item = &'a ExcerptId>,
 727        cx: &mut ModelContext<Self>,
 728    ) {
 729        let mut buffers = self.buffers.borrow_mut();
 730        let mut snapshot = self.snapshot.borrow_mut();
 731        let mut new_excerpts = SumTree::new();
 732        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
 733        let mut edits = Vec::new();
 734        let mut excerpt_ids = excerpt_ids.into_iter().peekable();
 735
 736        while let Some(mut excerpt_id) = excerpt_ids.next() {
 737            // Seek to the next excerpt to remove, preserving any preceding excerpts.
 738            new_excerpts.push_tree(cursor.slice(&Some(excerpt_id), Bias::Left, &()), &());
 739            if let Some(mut excerpt) = cursor.item() {
 740                if excerpt.id != *excerpt_id {
 741                    continue;
 742                }
 743                let mut old_start = cursor.start().1;
 744
 745                // Skip over the removed excerpt.
 746                loop {
 747                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
 748                        buffer_state.excerpts.retain(|id| id != excerpt_id);
 749                        if buffer_state.excerpts.is_empty() {
 750                            buffers.remove(&excerpt.buffer_id);
 751                        }
 752                    }
 753                    cursor.next(&());
 754
 755                    // Skip over any subsequent excerpts that are also removed.
 756                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
 757                        if let Some(next_excerpt) = cursor.item() {
 758                            if next_excerpt.id == *next_excerpt_id {
 759                                excerpt = next_excerpt;
 760                                excerpt_id = excerpt_ids.next().unwrap();
 761                                continue;
 762                            }
 763                        }
 764                    }
 765
 766                    break;
 767                }
 768
 769                // When removing the last excerpt, remove the trailing newline from
 770                // the previous excerpt.
 771                if cursor.item().is_none() && old_start > 0 {
 772                    old_start -= 1;
 773                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
 774                }
 775
 776                // Push an edit for the removal of this run of excerpts.
 777                let old_end = cursor.start().1;
 778                let new_start = new_excerpts.summary().text.bytes;
 779                edits.push(Edit {
 780                    old: old_start..old_end,
 781                    new: new_start..new_start,
 782                });
 783            }
 784        }
 785        new_excerpts.push_tree(cursor.suffix(&()), &());
 786        drop(cursor);
 787        snapshot.excerpts = new_excerpts;
 788        self.subscriptions.publish_mut(edits);
 789        cx.notify();
 790    }
 791
 792    fn on_buffer_event(
 793        &mut self,
 794        _: ModelHandle<Buffer>,
 795        event: &Event,
 796        cx: &mut ModelContext<Self>,
 797    ) {
 798        cx.emit(event.clone());
 799    }
 800
 801    pub fn format(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
 802        let mut format_tasks = Vec::new();
 803        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 804            format_tasks.push(buffer.update(cx, |buffer, cx| buffer.format(cx)));
 805        }
 806
 807        cx.spawn(|_, _| async move {
 808            for format in format_tasks {
 809                format.await?;
 810            }
 811            Ok(())
 812        })
 813    }
 814
 815    pub fn save(&mut self, cx: &mut ModelContext<Self>) -> Result<Task<Result<()>>> {
 816        let mut save_tasks = Vec::new();
 817        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 818            save_tasks.push(buffer.update(cx, |buffer, cx| buffer.save(cx))?);
 819        }
 820
 821        Ok(cx.spawn(|_, _| async move {
 822            for save in save_tasks {
 823                save.await?;
 824            }
 825            Ok(())
 826        }))
 827    }
 828
 829    pub fn language<'a>(&self, cx: &'a AppContext) -> Option<&'a Arc<Language>> {
 830        self.buffers
 831            .borrow()
 832            .values()
 833            .next()
 834            .and_then(|state| state.buffer.read(cx).language())
 835    }
 836
 837    pub fn file<'a>(&self, cx: &'a AppContext) -> Option<&'a dyn File> {
 838        self.as_singleton()?.read(cx).file()
 839    }
 840
 841    #[cfg(test)]
 842    pub fn is_parsing(&self, cx: &AppContext) -> bool {
 843        self.as_singleton().unwrap().read(cx).is_parsing()
 844    }
 845
 846    fn sync(&self, cx: &AppContext) {
 847        let mut snapshot = self.snapshot.borrow_mut();
 848        let mut excerpts_to_edit = Vec::new();
 849        let mut reparsed = false;
 850        let mut diagnostics_updated = false;
 851        let mut is_dirty = false;
 852        let mut has_conflict = false;
 853        let mut buffers = self.buffers.borrow_mut();
 854        for buffer_state in buffers.values_mut() {
 855            let buffer = buffer_state.buffer.read(cx);
 856            let version = buffer.version();
 857            let parse_count = buffer.parse_count();
 858            let selections_update_count = buffer.selections_update_count();
 859            let diagnostics_update_count = buffer.diagnostics_update_count();
 860
 861            let buffer_edited = version.changed_since(&buffer_state.last_version);
 862            let buffer_reparsed = parse_count > buffer_state.last_parse_count;
 863            let buffer_selections_updated =
 864                selections_update_count > buffer_state.last_selections_update_count;
 865            let buffer_diagnostics_updated =
 866                diagnostics_update_count > buffer_state.last_diagnostics_update_count;
 867            if buffer_edited
 868                || buffer_reparsed
 869                || buffer_selections_updated
 870                || buffer_diagnostics_updated
 871            {
 872                buffer_state.last_version = version;
 873                buffer_state.last_parse_count = parse_count;
 874                buffer_state.last_selections_update_count = selections_update_count;
 875                buffer_state.last_diagnostics_update_count = diagnostics_update_count;
 876                excerpts_to_edit.extend(
 877                    buffer_state
 878                        .excerpts
 879                        .iter()
 880                        .map(|excerpt_id| (excerpt_id, buffer_state.buffer.clone(), buffer_edited)),
 881                );
 882            }
 883
 884            reparsed |= buffer_reparsed;
 885            diagnostics_updated |= buffer_diagnostics_updated;
 886            is_dirty |= buffer.is_dirty();
 887            has_conflict |= buffer.has_conflict();
 888        }
 889        if reparsed {
 890            snapshot.parse_count += 1;
 891        }
 892        if diagnostics_updated {
 893            snapshot.diagnostics_update_count += 1;
 894        }
 895        snapshot.is_dirty = is_dirty;
 896        snapshot.has_conflict = has_conflict;
 897
 898        excerpts_to_edit.sort_unstable_by_key(|(excerpt_id, _, _)| *excerpt_id);
 899
 900        let mut edits = Vec::new();
 901        let mut new_excerpts = SumTree::new();
 902        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
 903
 904        for (id, buffer, buffer_edited) in excerpts_to_edit {
 905            new_excerpts.push_tree(cursor.slice(&Some(id), Bias::Left, &()), &());
 906            let old_excerpt = cursor.item().unwrap();
 907            let buffer_id = buffer.id();
 908            let buffer = buffer.read(cx);
 909
 910            let mut new_excerpt;
 911            if buffer_edited {
 912                edits.extend(
 913                    buffer
 914                        .edits_since_in_range::<usize>(
 915                            old_excerpt.buffer.version(),
 916                            old_excerpt.range.clone(),
 917                        )
 918                        .map(|mut edit| {
 919                            let excerpt_old_start = cursor.start().1;
 920                            let excerpt_new_start = new_excerpts.summary().text.bytes;
 921                            edit.old.start += excerpt_old_start;
 922                            edit.old.end += excerpt_old_start;
 923                            edit.new.start += excerpt_new_start;
 924                            edit.new.end += excerpt_new_start;
 925                            edit
 926                        }),
 927                );
 928
 929                new_excerpt = Excerpt::new(
 930                    id.clone(),
 931                    buffer_id,
 932                    buffer.snapshot(),
 933                    old_excerpt.range.clone(),
 934                    old_excerpt.has_trailing_newline,
 935                );
 936            } else {
 937                new_excerpt = old_excerpt.clone();
 938                new_excerpt.buffer = buffer.snapshot();
 939            }
 940
 941            new_excerpts.push(new_excerpt, &());
 942            cursor.next(&());
 943        }
 944        new_excerpts.push_tree(cursor.suffix(&()), &());
 945
 946        drop(cursor);
 947        snapshot.excerpts = new_excerpts;
 948
 949        self.subscriptions.publish(edits);
 950    }
 951}
 952
 953#[cfg(any(test, feature = "test-support"))]
 954impl MultiBuffer {
 955    pub fn randomly_edit(
 956        &mut self,
 957        rng: &mut impl rand::Rng,
 958        count: usize,
 959        cx: &mut ModelContext<Self>,
 960    ) {
 961        use text::RandomCharIter;
 962
 963        let snapshot = self.read(cx);
 964        let mut old_ranges: Vec<Range<usize>> = Vec::new();
 965        for _ in 0..count {
 966            let last_end = old_ranges.last().map_or(0, |last_range| last_range.end + 1);
 967            if last_end > snapshot.len() {
 968                break;
 969            }
 970            let end_ix = snapshot.clip_offset(rng.gen_range(0..=last_end), Bias::Right);
 971            let start_ix = snapshot.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
 972            old_ranges.push(start_ix..end_ix);
 973        }
 974        let new_text_len = rng.gen_range(0..10);
 975        let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
 976        log::info!("mutating multi-buffer at {:?}: {:?}", old_ranges, new_text);
 977        drop(snapshot);
 978
 979        self.edit(old_ranges.iter().cloned(), new_text.as_str(), cx);
 980    }
 981}
 982
 983impl Entity for MultiBuffer {
 984    type Event = language::Event;
 985}
 986
 987impl MultiBufferSnapshot {
 988    pub fn text(&self) -> String {
 989        self.chunks(0..self.len(), None)
 990            .map(|chunk| chunk.text)
 991            .collect()
 992    }
 993
 994    pub fn reversed_chars_at<'a, T: ToOffset>(
 995        &'a self,
 996        position: T,
 997    ) -> impl Iterator<Item = char> + 'a {
 998        let mut offset = position.to_offset(self);
 999        let mut cursor = self.excerpts.cursor::<usize>();
1000        cursor.seek(&offset, Bias::Left, &());
1001        let mut excerpt_chunks = cursor.item().map(|excerpt| {
1002            let end_before_footer = cursor.start() + excerpt.text_summary.bytes;
1003            let start = excerpt.range.start.to_offset(&excerpt.buffer);
1004            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
1005            excerpt.buffer.reversed_chunks_in_range(start..end)
1006        });
1007        iter::from_fn(move || {
1008            if offset == *cursor.start() {
1009                cursor.prev(&());
1010                let excerpt = cursor.item()?;
1011                excerpt_chunks = Some(
1012                    excerpt
1013                        .buffer
1014                        .reversed_chunks_in_range(excerpt.range.clone()),
1015                );
1016            }
1017
1018            let excerpt = cursor.item().unwrap();
1019            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
1020                offset -= 1;
1021                Some("\n")
1022            } else {
1023                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
1024                offset -= chunk.len();
1025                Some(chunk)
1026            }
1027        })
1028        .flat_map(|c| c.chars().rev())
1029    }
1030
1031    pub fn chars_at<'a, T: ToOffset>(&'a self, position: T) -> impl Iterator<Item = char> + 'a {
1032        let offset = position.to_offset(self);
1033        self.text_for_range(offset..self.len())
1034            .flat_map(|chunk| chunk.chars())
1035    }
1036
1037    pub fn text_for_range<'a, T: ToOffset>(
1038        &'a self,
1039        range: Range<T>,
1040    ) -> impl Iterator<Item = &'a str> {
1041        self.chunks(range, None).map(|chunk| chunk.text)
1042    }
1043
1044    pub fn is_line_blank(&self, row: u32) -> bool {
1045        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1046            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1047    }
1048
1049    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1050    where
1051        T: ToOffset,
1052    {
1053        let position = position.to_offset(self);
1054        position == self.clip_offset(position, Bias::Left)
1055            && self
1056                .bytes_in_range(position..self.len())
1057                .flatten()
1058                .copied()
1059                .take(needle.len())
1060                .eq(needle.bytes())
1061    }
1062
1063    fn as_singleton(&self) -> Option<&BufferSnapshot> {
1064        let mut excerpts = self.excerpts.iter();
1065        let buffer = excerpts.next().map(|excerpt| &excerpt.buffer);
1066        if excerpts.next().is_none() {
1067            buffer
1068        } else {
1069            None
1070        }
1071    }
1072
1073    pub fn len(&self) -> usize {
1074        self.excerpts.summary().text.bytes
1075    }
1076
1077    pub fn max_buffer_row(&self) -> u32 {
1078        self.excerpts.summary().max_buffer_row
1079    }
1080
1081    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
1082        let mut cursor = self.excerpts.cursor::<usize>();
1083        cursor.seek(&offset, Bias::Right, &());
1084        let overshoot = if let Some(excerpt) = cursor.item() {
1085            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1086            let buffer_offset = excerpt
1087                .buffer
1088                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
1089            buffer_offset.saturating_sub(excerpt_start)
1090        } else {
1091            0
1092        };
1093        cursor.start() + overshoot
1094    }
1095
1096    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1097        let mut cursor = self.excerpts.cursor::<Point>();
1098        cursor.seek(&point, Bias::Right, &());
1099        let overshoot = if let Some(excerpt) = cursor.item() {
1100            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1101            let buffer_point = excerpt
1102                .buffer
1103                .clip_point(excerpt_start + (point - cursor.start()), bias);
1104            buffer_point.saturating_sub(excerpt_start)
1105        } else {
1106            Point::zero()
1107        };
1108        *cursor.start() + overshoot
1109    }
1110
1111    pub fn clip_point_utf16(&self, point: PointUtf16, bias: Bias) -> PointUtf16 {
1112        let mut cursor = self.excerpts.cursor::<PointUtf16>();
1113        cursor.seek(&point, Bias::Right, &());
1114        let overshoot = if let Some(excerpt) = cursor.item() {
1115            let excerpt_start = excerpt
1116                .buffer
1117                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1118            let buffer_point = excerpt
1119                .buffer
1120                .clip_point_utf16(excerpt_start + (point - cursor.start()), bias);
1121            buffer_point.saturating_sub(excerpt_start)
1122        } else {
1123            PointUtf16::zero()
1124        };
1125        *cursor.start() + overshoot
1126    }
1127
1128    pub fn bytes_in_range<'a, T: ToOffset>(&'a self, range: Range<T>) -> MultiBufferBytes<'a> {
1129        let range = range.start.to_offset(self)..range.end.to_offset(self);
1130        let mut excerpts = self.excerpts.cursor::<usize>();
1131        excerpts.seek(&range.start, Bias::Right, &());
1132
1133        let mut chunk = &[][..];
1134        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
1135            let mut excerpt_bytes = excerpt
1136                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
1137            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
1138            Some(excerpt_bytes)
1139        } else {
1140            None
1141        };
1142
1143        MultiBufferBytes {
1144            range,
1145            excerpts,
1146            excerpt_bytes,
1147            chunk,
1148        }
1149    }
1150
1151    pub fn buffer_rows<'a>(&'a self, start_row: u32) -> MultiBufferRows<'a> {
1152        let mut result = MultiBufferRows {
1153            buffer_row_range: 0..0,
1154            excerpts: self.excerpts.cursor(),
1155        };
1156        result.seek(start_row);
1157        result
1158    }
1159
1160    pub fn chunks<'a, T: ToOffset>(
1161        &'a self,
1162        range: Range<T>,
1163        theme: Option<&'a SyntaxTheme>,
1164    ) -> MultiBufferChunks<'a> {
1165        let range = range.start.to_offset(self)..range.end.to_offset(self);
1166        let mut chunks = MultiBufferChunks {
1167            range: range.clone(),
1168            excerpts: self.excerpts.cursor(),
1169            excerpt_chunks: None,
1170            theme,
1171        };
1172        chunks.seek(range.start);
1173        chunks
1174    }
1175
1176    pub fn offset_to_point(&self, offset: usize) -> Point {
1177        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1178        cursor.seek(&offset, Bias::Right, &());
1179        if let Some(excerpt) = cursor.item() {
1180            let (start_offset, start_point) = cursor.start();
1181            let overshoot = offset - start_offset;
1182            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1183            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1184            let buffer_point = excerpt
1185                .buffer
1186                .offset_to_point(excerpt_start_offset + overshoot);
1187            *start_point + (buffer_point - excerpt_start_point)
1188        } else {
1189            self.excerpts.summary().text.lines
1190        }
1191    }
1192
1193    pub fn point_to_offset(&self, point: Point) -> usize {
1194        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
1195        cursor.seek(&point, Bias::Right, &());
1196        if let Some(excerpt) = cursor.item() {
1197            let (start_point, start_offset) = cursor.start();
1198            let overshoot = point - start_point;
1199            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1200            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1201            let buffer_offset = excerpt
1202                .buffer
1203                .point_to_offset(excerpt_start_point + overshoot);
1204            *start_offset + buffer_offset - excerpt_start_offset
1205        } else {
1206            self.excerpts.summary().text.bytes
1207        }
1208    }
1209
1210    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
1211        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
1212        cursor.seek(&point, Bias::Right, &());
1213        if let Some(excerpt) = cursor.item() {
1214            let (start_point, start_offset) = cursor.start();
1215            let overshoot = point - start_point;
1216            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1217            let excerpt_start_point = excerpt
1218                .buffer
1219                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1220            let buffer_offset = excerpt
1221                .buffer
1222                .point_utf16_to_offset(excerpt_start_point + overshoot);
1223            *start_offset + (buffer_offset - excerpt_start_offset)
1224        } else {
1225            self.excerpts.summary().text.bytes
1226        }
1227    }
1228
1229    pub fn indent_column_for_line(&self, row: u32) -> u32 {
1230        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
1231            buffer
1232                .indent_column_for_line(range.start.row)
1233                .min(range.end.column)
1234                .saturating_sub(range.start.column)
1235        } else {
1236            0
1237        }
1238    }
1239
1240    pub fn line_len(&self, row: u32) -> u32 {
1241        if let Some((_, range)) = self.buffer_line_for_row(row) {
1242            range.end.column - range.start.column
1243        } else {
1244            0
1245        }
1246    }
1247
1248    fn buffer_line_for_row(&self, row: u32) -> Option<(&BufferSnapshot, Range<Point>)> {
1249        let mut cursor = self.excerpts.cursor::<Point>();
1250        cursor.seek(&Point::new(row, 0), Bias::Right, &());
1251        if let Some(excerpt) = cursor.item() {
1252            let overshoot = row - cursor.start().row;
1253            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1254            let excerpt_end = excerpt.range.end.to_point(&excerpt.buffer);
1255            let buffer_row = excerpt_start.row + overshoot;
1256            let line_start = Point::new(buffer_row, 0);
1257            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
1258            return Some((
1259                &excerpt.buffer,
1260                line_start.max(excerpt_start)..line_end.min(excerpt_end),
1261            ));
1262        }
1263        None
1264    }
1265
1266    pub fn max_point(&self) -> Point {
1267        self.text_summary().lines
1268    }
1269
1270    pub fn text_summary(&self) -> TextSummary {
1271        self.excerpts.summary().text
1272    }
1273
1274    pub fn text_summary_for_range<'a, D, O>(&'a self, range: Range<O>) -> D
1275    where
1276        D: TextDimension,
1277        O: ToOffset,
1278    {
1279        let mut summary = D::default();
1280        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
1281        let mut cursor = self.excerpts.cursor::<usize>();
1282        cursor.seek(&range.start, Bias::Right, &());
1283        if let Some(excerpt) = cursor.item() {
1284            let mut end_before_newline = cursor.end(&());
1285            if excerpt.has_trailing_newline {
1286                end_before_newline -= 1;
1287            }
1288
1289            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1290            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
1291            let end_in_excerpt =
1292                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
1293            summary.add_assign(
1294                &excerpt
1295                    .buffer
1296                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
1297            );
1298
1299            if range.end > end_before_newline {
1300                summary.add_assign(&D::from_text_summary(&TextSummary {
1301                    bytes: 1,
1302                    lines: Point::new(1 as u32, 0),
1303                    lines_utf16: PointUtf16::new(1 as u32, 0),
1304                    first_line_chars: 0,
1305                    last_line_chars: 0,
1306                    longest_row: 0,
1307                    longest_row_chars: 0,
1308                }));
1309            }
1310
1311            cursor.next(&());
1312        }
1313
1314        if range.end > *cursor.start() {
1315            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
1316                &range.end,
1317                Bias::Right,
1318                &(),
1319            )));
1320            if let Some(excerpt) = cursor.item() {
1321                range.end = cmp::max(*cursor.start(), range.end);
1322
1323                let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1324                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
1325                summary.add_assign(
1326                    &excerpt
1327                        .buffer
1328                        .text_summary_for_range(excerpt_start..end_in_excerpt),
1329                );
1330            }
1331        }
1332
1333        summary
1334    }
1335
1336    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
1337    where
1338        D: TextDimension + Ord + Sub<D, Output = D>,
1339    {
1340        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1341        cursor.seek(&Some(&anchor.excerpt_id), Bias::Left, &());
1342        if cursor.item().is_none() {
1343            cursor.next(&());
1344        }
1345
1346        let mut position = D::from_text_summary(&cursor.start().text);
1347        if let Some(excerpt) = cursor.item() {
1348            if excerpt.id == anchor.excerpt_id && excerpt.buffer_id == anchor.buffer_id {
1349                let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1350                let buffer_position = anchor.text_anchor.summary::<D>(&excerpt.buffer);
1351                if buffer_position > excerpt_buffer_start {
1352                    position.add_assign(&(buffer_position - excerpt_buffer_start));
1353                }
1354            }
1355        }
1356        position
1357    }
1358
1359    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
1360    where
1361        D: TextDimension + Ord + Sub<D, Output = D>,
1362        I: 'a + IntoIterator<Item = &'a Anchor>,
1363    {
1364        let mut anchors = anchors.into_iter().peekable();
1365        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1366        let mut summaries = Vec::new();
1367        while let Some(anchor) = anchors.peek() {
1368            let excerpt_id = &anchor.excerpt_id;
1369            let buffer_id = anchor.buffer_id;
1370            let excerpt_anchors = iter::from_fn(|| {
1371                let anchor = anchors.peek()?;
1372                if anchor.excerpt_id == *excerpt_id && anchor.buffer_id == buffer_id {
1373                    Some(&anchors.next().unwrap().text_anchor)
1374                } else {
1375                    None
1376                }
1377            });
1378
1379            cursor.seek_forward(&Some(excerpt_id), Bias::Left, &());
1380            if cursor.item().is_none() {
1381                cursor.next(&());
1382            }
1383
1384            let position = D::from_text_summary(&cursor.start().text);
1385            if let Some(excerpt) = cursor.item() {
1386                if excerpt.id == *excerpt_id && excerpt.buffer_id == buffer_id {
1387                    let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1388                    summaries.extend(
1389                        excerpt
1390                            .buffer
1391                            .summaries_for_anchors::<D, _>(excerpt_anchors)
1392                            .map(move |summary| {
1393                                let mut position = position.clone();
1394                                let excerpt_buffer_start = excerpt_buffer_start.clone();
1395                                if summary > excerpt_buffer_start {
1396                                    position.add_assign(&(summary - excerpt_buffer_start));
1397                                }
1398                                position
1399                            }),
1400                    );
1401                    continue;
1402                }
1403            }
1404
1405            summaries.extend(excerpt_anchors.map(|_| position.clone()));
1406        }
1407
1408        summaries
1409    }
1410
1411    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
1412    where
1413        I: 'a + IntoIterator<Item = &'a Anchor>,
1414    {
1415        let mut anchors = anchors.into_iter().enumerate().peekable();
1416        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1417        let mut result = Vec::new();
1418        while let Some((_, anchor)) = anchors.peek() {
1419            let old_excerpt_id = &anchor.excerpt_id;
1420
1421            // Find the location where this anchor's excerpt should be.
1422            cursor.seek_forward(&Some(old_excerpt_id), Bias::Left, &());
1423            if cursor.item().is_none() {
1424                cursor.next(&());
1425            }
1426
1427            let next_excerpt = cursor.item();
1428            let prev_excerpt = cursor.prev_item();
1429
1430            // Process all of the anchors for this excerpt.
1431            while let Some((_, anchor)) = anchors.peek() {
1432                if anchor.excerpt_id != *old_excerpt_id {
1433                    break;
1434                }
1435                let mut kept_position = false;
1436                let (anchor_ix, anchor) = anchors.next().unwrap();
1437                let mut anchor = anchor.clone();
1438
1439                // Leave min and max anchors unchanged.
1440                if *old_excerpt_id == ExcerptId::max() || *old_excerpt_id == ExcerptId::min() {
1441                    kept_position = true;
1442                }
1443                // If the old excerpt still exists at this location, then leave
1444                // the anchor unchanged.
1445                else if next_excerpt.map_or(false, |excerpt| {
1446                    excerpt.id == *old_excerpt_id && excerpt.buffer_id == anchor.buffer_id
1447                }) {
1448                    kept_position = true;
1449                }
1450                // If the old excerpt no longer exists at this location, then attempt to
1451                // find an equivalent position for this anchor in an adjacent excerpt.
1452                else {
1453                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
1454                        if excerpt.contains(&anchor) {
1455                            anchor.excerpt_id = excerpt.id.clone();
1456                            kept_position = true;
1457                            break;
1458                        }
1459                    }
1460                }
1461                // If there's no adjacent excerpt that contains the anchor's position,
1462                // then report that the anchor has lost its position.
1463                if !kept_position {
1464                    anchor = if let Some(excerpt) = next_excerpt {
1465                        Anchor {
1466                            buffer_id: excerpt.buffer_id,
1467                            excerpt_id: excerpt.id.clone(),
1468                            text_anchor: excerpt
1469                                .buffer
1470                                .anchor_at(&excerpt.range.start, anchor.text_anchor.bias),
1471                        }
1472                    } else if let Some(excerpt) = prev_excerpt {
1473                        Anchor {
1474                            buffer_id: excerpt.buffer_id,
1475                            excerpt_id: excerpt.id.clone(),
1476                            text_anchor: excerpt
1477                                .buffer
1478                                .anchor_at(&excerpt.range.end, anchor.text_anchor.bias),
1479                        }
1480                    } else if anchor.text_anchor.bias == Bias::Left {
1481                        Anchor::min()
1482                    } else {
1483                        Anchor::max()
1484                    };
1485                }
1486
1487                result.push((anchor_ix, anchor, kept_position));
1488            }
1489        }
1490        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self).unwrap());
1491        result
1492    }
1493
1494    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
1495        self.anchor_at(position, Bias::Left)
1496    }
1497
1498    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
1499        self.anchor_at(position, Bias::Right)
1500    }
1501
1502    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
1503        let offset = position.to_offset(self);
1504        let mut cursor = self.excerpts.cursor::<(usize, Option<&ExcerptId>)>();
1505        cursor.seek(&offset, Bias::Right, &());
1506        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
1507            cursor.prev(&());
1508        }
1509        if let Some(excerpt) = cursor.item() {
1510            let mut overshoot = offset.saturating_sub(cursor.start().0);
1511            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
1512                overshoot -= 1;
1513                bias = Bias::Right;
1514            }
1515
1516            let buffer_start = excerpt.range.start.to_offset(&excerpt.buffer);
1517            let text_anchor =
1518                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
1519            Anchor {
1520                buffer_id: excerpt.buffer_id,
1521                excerpt_id: excerpt.id.clone(),
1522                text_anchor,
1523            }
1524        } else if offset == 0 && bias == Bias::Left {
1525            Anchor::min()
1526        } else {
1527            Anchor::max()
1528        }
1529    }
1530
1531    pub fn anchor_in_excerpt(&self, excerpt_id: ExcerptId, text_anchor: text::Anchor) -> Anchor {
1532        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1533        cursor.seek(&Some(&excerpt_id), Bias::Left, &());
1534        if let Some(excerpt) = cursor.item() {
1535            if excerpt.id == excerpt_id {
1536                let text_anchor = excerpt.clip_anchor(text_anchor);
1537                drop(cursor);
1538                return Anchor {
1539                    buffer_id: excerpt.buffer_id,
1540                    excerpt_id,
1541                    text_anchor,
1542                };
1543            }
1544        }
1545        panic!("excerpt not found");
1546    }
1547
1548    pub fn range_contains_excerpt_boundary<T: ToOffset>(&self, range: Range<T>) -> bool {
1549        let start = range.start.to_offset(self);
1550        let end = range.end.to_offset(self);
1551        let mut cursor = self.excerpts.cursor::<(usize, Option<&ExcerptId>)>();
1552        cursor.seek(&start, Bias::Right, &());
1553        let start_id = cursor
1554            .item()
1555            .or_else(|| cursor.prev_item())
1556            .map(|excerpt| &excerpt.id);
1557        cursor.seek_forward(&end, Bias::Right, &());
1558        let end_id = cursor
1559            .item()
1560            .or_else(|| cursor.prev_item())
1561            .map(|excerpt| &excerpt.id);
1562        start_id != end_id
1563    }
1564
1565    pub fn parse_count(&self) -> usize {
1566        self.parse_count
1567    }
1568
1569    pub fn enclosing_bracket_ranges<T: ToOffset>(
1570        &self,
1571        range: Range<T>,
1572    ) -> Option<(Range<usize>, Range<usize>)> {
1573        let range = range.start.to_offset(self)..range.end.to_offset(self);
1574
1575        let mut cursor = self.excerpts.cursor::<usize>();
1576        cursor.seek(&range.start, Bias::Right, &());
1577        let start_excerpt = cursor.item();
1578
1579        cursor.seek(&range.end, Bias::Right, &());
1580        let end_excerpt = cursor.item();
1581
1582        start_excerpt
1583            .zip(end_excerpt)
1584            .and_then(|(start_excerpt, end_excerpt)| {
1585                if start_excerpt.id != end_excerpt.id {
1586                    return None;
1587                }
1588
1589                let excerpt_buffer_start =
1590                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
1591                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
1592
1593                let start_in_buffer =
1594                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
1595                let end_in_buffer =
1596                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
1597                let (mut start_bracket_range, mut end_bracket_range) = start_excerpt
1598                    .buffer
1599                    .enclosing_bracket_ranges(start_in_buffer..end_in_buffer)?;
1600
1601                if start_bracket_range.start >= excerpt_buffer_start
1602                    && end_bracket_range.end < excerpt_buffer_end
1603                {
1604                    start_bracket_range.start =
1605                        cursor.start() + (start_bracket_range.start - excerpt_buffer_start);
1606                    start_bracket_range.end =
1607                        cursor.start() + (start_bracket_range.end - excerpt_buffer_start);
1608                    end_bracket_range.start =
1609                        cursor.start() + (end_bracket_range.start - excerpt_buffer_start);
1610                    end_bracket_range.end =
1611                        cursor.start() + (end_bracket_range.end - excerpt_buffer_start);
1612                    Some((start_bracket_range, end_bracket_range))
1613                } else {
1614                    None
1615                }
1616            })
1617    }
1618
1619    pub fn diagnostics_update_count(&self) -> usize {
1620        self.diagnostics_update_count
1621    }
1622
1623    pub fn language(&self) -> Option<&Arc<Language>> {
1624        self.excerpts
1625            .iter()
1626            .next()
1627            .and_then(|excerpt| excerpt.buffer.language())
1628    }
1629
1630    pub fn is_dirty(&self) -> bool {
1631        self.is_dirty
1632    }
1633
1634    pub fn has_conflict(&self) -> bool {
1635        self.has_conflict
1636    }
1637
1638    pub fn diagnostic_group<'a, O>(
1639        &'a self,
1640        group_id: usize,
1641    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
1642    where
1643        O: text::FromAnchor + 'a,
1644    {
1645        self.as_singleton()
1646            .into_iter()
1647            .flat_map(move |buffer| buffer.diagnostic_group(group_id))
1648    }
1649
1650    pub fn diagnostics_in_range<'a, T, O>(
1651        &'a self,
1652        range: Range<T>,
1653    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
1654    where
1655        T: 'a + ToOffset,
1656        O: 'a + text::FromAnchor,
1657    {
1658        self.as_singleton().into_iter().flat_map(move |buffer| {
1659            buffer.diagnostics_in_range(range.start.to_offset(self)..range.end.to_offset(self))
1660        })
1661    }
1662
1663    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
1664        let range = range.start.to_offset(self)..range.end.to_offset(self);
1665
1666        let mut cursor = self.excerpts.cursor::<usize>();
1667        cursor.seek(&range.start, Bias::Right, &());
1668        let start_excerpt = cursor.item();
1669
1670        cursor.seek(&range.end, Bias::Right, &());
1671        let end_excerpt = cursor.item();
1672
1673        start_excerpt
1674            .zip(end_excerpt)
1675            .and_then(|(start_excerpt, end_excerpt)| {
1676                if start_excerpt.id != end_excerpt.id {
1677                    return None;
1678                }
1679
1680                let excerpt_buffer_start =
1681                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
1682                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
1683
1684                let start_in_buffer =
1685                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
1686                let end_in_buffer =
1687                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
1688                let mut ancestor_buffer_range = start_excerpt
1689                    .buffer
1690                    .range_for_syntax_ancestor(start_in_buffer..end_in_buffer)?;
1691                ancestor_buffer_range.start =
1692                    cmp::max(ancestor_buffer_range.start, excerpt_buffer_start);
1693                ancestor_buffer_range.end = cmp::min(ancestor_buffer_range.end, excerpt_buffer_end);
1694
1695                let start = cursor.start() + (ancestor_buffer_range.start - excerpt_buffer_start);
1696                let end = cursor.start() + (ancestor_buffer_range.end - excerpt_buffer_start);
1697                Some(start..end)
1698            })
1699    }
1700
1701    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
1702        let buffer = self.as_singleton()?;
1703        let outline = buffer.outline(theme)?;
1704        let excerpt_id = &self.excerpts.iter().next().unwrap().id;
1705        Some(Outline::new(
1706            outline
1707                .items
1708                .into_iter()
1709                .map(|item| OutlineItem {
1710                    depth: item.depth,
1711                    range: self.anchor_in_excerpt(excerpt_id.clone(), item.range.start)
1712                        ..self.anchor_in_excerpt(excerpt_id.clone(), item.range.end),
1713                    text: item.text,
1714                    highlight_ranges: item.highlight_ranges,
1715                })
1716                .collect(),
1717        ))
1718    }
1719
1720    fn buffer_snapshot_for_excerpt<'a>(
1721        &'a self,
1722        excerpt_id: &'a ExcerptId,
1723    ) -> Option<(usize, &'a BufferSnapshot)> {
1724        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1725        cursor.seek(&Some(excerpt_id), Bias::Left, &());
1726        if let Some(excerpt) = cursor.item() {
1727            if excerpt.id == *excerpt_id {
1728                return Some((excerpt.buffer_id, &excerpt.buffer));
1729            }
1730        }
1731        None
1732    }
1733
1734    pub fn remote_selections_in_range<'a>(
1735        &'a self,
1736        range: &'a Range<Anchor>,
1737    ) -> impl 'a + Iterator<Item = (ReplicaId, Selection<Anchor>)> {
1738        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1739        cursor.seek(&Some(&range.start.excerpt_id), Bias::Left, &());
1740        cursor
1741            .take_while(move |excerpt| excerpt.id <= range.end.excerpt_id)
1742            .flat_map(move |excerpt| {
1743                let mut query_range = excerpt.range.start.clone()..excerpt.range.end.clone();
1744                if excerpt.id == range.start.excerpt_id {
1745                    query_range.start = range.start.text_anchor.clone();
1746                }
1747                if excerpt.id == range.end.excerpt_id {
1748                    query_range.end = range.end.text_anchor.clone();
1749                }
1750
1751                excerpt
1752                    .buffer
1753                    .remote_selections_in_range(query_range)
1754                    .flat_map(move |(replica_id, selections)| {
1755                        selections.map(move |selection| {
1756                            let mut start = Anchor {
1757                                buffer_id: excerpt.buffer_id,
1758                                excerpt_id: excerpt.id.clone(),
1759                                text_anchor: selection.start.clone(),
1760                            };
1761                            let mut end = Anchor {
1762                                buffer_id: excerpt.buffer_id,
1763                                excerpt_id: excerpt.id.clone(),
1764                                text_anchor: selection.end.clone(),
1765                            };
1766                            if range.start.cmp(&start, self).unwrap().is_gt() {
1767                                start = range.start.clone();
1768                            }
1769                            if range.end.cmp(&end, self).unwrap().is_lt() {
1770                                end = range.end.clone();
1771                            }
1772
1773                            (
1774                                replica_id,
1775                                Selection {
1776                                    id: selection.id,
1777                                    start,
1778                                    end,
1779                                    reversed: selection.reversed,
1780                                    goal: selection.goal,
1781                                },
1782                            )
1783                        })
1784                    })
1785            })
1786    }
1787}
1788
1789impl History {
1790    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
1791        self.transaction_depth += 1;
1792        if self.transaction_depth == 1 {
1793            let id = post_inc(&mut self.next_transaction_id);
1794            self.undo_stack.push(Transaction {
1795                id,
1796                buffer_transactions: Default::default(),
1797                first_edit_at: now,
1798                last_edit_at: now,
1799            });
1800            Some(id)
1801        } else {
1802            None
1803        }
1804    }
1805
1806    fn end_transaction(
1807        &mut self,
1808        now: Instant,
1809        buffer_transactions: HashSet<(usize, TransactionId)>,
1810    ) -> bool {
1811        assert_ne!(self.transaction_depth, 0);
1812        self.transaction_depth -= 1;
1813        if self.transaction_depth == 0 {
1814            if buffer_transactions.is_empty() {
1815                self.undo_stack.pop();
1816                false
1817            } else {
1818                let transaction = self.undo_stack.last_mut().unwrap();
1819                transaction.last_edit_at = now;
1820                transaction.buffer_transactions.extend(buffer_transactions);
1821                true
1822            }
1823        } else {
1824            false
1825        }
1826    }
1827
1828    fn pop_undo(&mut self) -> Option<&Transaction> {
1829        assert_eq!(self.transaction_depth, 0);
1830        if let Some(transaction) = self.undo_stack.pop() {
1831            self.redo_stack.push(transaction);
1832            self.redo_stack.last()
1833        } else {
1834            None
1835        }
1836    }
1837
1838    fn pop_redo(&mut self) -> Option<&Transaction> {
1839        assert_eq!(self.transaction_depth, 0);
1840        if let Some(transaction) = self.redo_stack.pop() {
1841            self.undo_stack.push(transaction);
1842            self.undo_stack.last()
1843        } else {
1844            None
1845        }
1846    }
1847
1848    fn group(&mut self) -> Option<TransactionId> {
1849        let mut new_len = self.undo_stack.len();
1850        let mut transactions = self.undo_stack.iter_mut();
1851
1852        if let Some(mut transaction) = transactions.next_back() {
1853            while let Some(prev_transaction) = transactions.next_back() {
1854                if transaction.first_edit_at - prev_transaction.last_edit_at <= self.group_interval
1855                {
1856                    transaction = prev_transaction;
1857                    new_len -= 1;
1858                } else {
1859                    break;
1860                }
1861            }
1862        }
1863
1864        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
1865        if let Some(last_transaction) = transactions_to_keep.last_mut() {
1866            if let Some(transaction) = transactions_to_merge.last() {
1867                last_transaction.last_edit_at = transaction.last_edit_at;
1868            }
1869        }
1870
1871        self.undo_stack.truncate(new_len);
1872        self.undo_stack.last().map(|t| t.id)
1873    }
1874}
1875
1876impl Excerpt {
1877    fn new(
1878        id: ExcerptId,
1879        buffer_id: usize,
1880        buffer: BufferSnapshot,
1881        range: Range<text::Anchor>,
1882        has_trailing_newline: bool,
1883    ) -> Self {
1884        Excerpt {
1885            id,
1886            max_buffer_row: range.end.to_point(&buffer).row,
1887            text_summary: buffer.text_summary_for_range::<TextSummary, _>(range.to_offset(&buffer)),
1888            buffer_id,
1889            buffer,
1890            range,
1891            has_trailing_newline,
1892        }
1893    }
1894
1895    fn chunks_in_range<'a>(
1896        &'a self,
1897        range: Range<usize>,
1898        theme: Option<&'a SyntaxTheme>,
1899    ) -> ExcerptChunks<'a> {
1900        let content_start = self.range.start.to_offset(&self.buffer);
1901        let chunks_start = content_start + range.start;
1902        let chunks_end = content_start + cmp::min(range.end, self.text_summary.bytes);
1903
1904        let footer_height = if self.has_trailing_newline
1905            && range.start <= self.text_summary.bytes
1906            && range.end > self.text_summary.bytes
1907        {
1908            1
1909        } else {
1910            0
1911        };
1912
1913        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, theme);
1914
1915        ExcerptChunks {
1916            content_chunks,
1917            footer_height,
1918        }
1919    }
1920
1921    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
1922        let content_start = self.range.start.to_offset(&self.buffer);
1923        let bytes_start = content_start + range.start;
1924        let bytes_end = content_start + cmp::min(range.end, self.text_summary.bytes);
1925        let footer_height = if self.has_trailing_newline
1926            && range.start <= self.text_summary.bytes
1927            && range.end > self.text_summary.bytes
1928        {
1929            1
1930        } else {
1931            0
1932        };
1933        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
1934
1935        ExcerptBytes {
1936            content_bytes,
1937            footer_height,
1938        }
1939    }
1940
1941    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
1942        if text_anchor
1943            .cmp(&self.range.start, &self.buffer)
1944            .unwrap()
1945            .is_lt()
1946        {
1947            self.range.start.clone()
1948        } else if text_anchor
1949            .cmp(&self.range.end, &self.buffer)
1950            .unwrap()
1951            .is_gt()
1952        {
1953            self.range.end.clone()
1954        } else {
1955            text_anchor
1956        }
1957    }
1958
1959    fn contains(&self, anchor: &Anchor) -> bool {
1960        self.buffer_id == anchor.buffer_id
1961            && self
1962                .range
1963                .start
1964                .cmp(&anchor.text_anchor, &self.buffer)
1965                .unwrap()
1966                .is_le()
1967            && self
1968                .range
1969                .end
1970                .cmp(&anchor.text_anchor, &self.buffer)
1971                .unwrap()
1972                .is_ge()
1973    }
1974}
1975
1976impl fmt::Debug for Excerpt {
1977    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1978        f.debug_struct("Excerpt")
1979            .field("id", &self.id)
1980            .field("buffer_id", &self.buffer_id)
1981            .field("range", &self.range)
1982            .field("text_summary", &self.text_summary)
1983            .field("has_trailing_newline", &self.has_trailing_newline)
1984            .finish()
1985    }
1986}
1987
1988impl sum_tree::Item for Excerpt {
1989    type Summary = ExcerptSummary;
1990
1991    fn summary(&self) -> Self::Summary {
1992        let mut text = self.text_summary.clone();
1993        if self.has_trailing_newline {
1994            text += TextSummary::from("\n");
1995        }
1996        ExcerptSummary {
1997            excerpt_id: self.id.clone(),
1998            max_buffer_row: self.max_buffer_row,
1999            text,
2000        }
2001    }
2002}
2003
2004impl sum_tree::Summary for ExcerptSummary {
2005    type Context = ();
2006
2007    fn add_summary(&mut self, summary: &Self, _: &()) {
2008        debug_assert!(summary.excerpt_id > self.excerpt_id);
2009        self.excerpt_id = summary.excerpt_id.clone();
2010        self.text.add_summary(&summary.text, &());
2011        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
2012    }
2013}
2014
2015impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
2016    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2017        *self += &summary.text;
2018    }
2019}
2020
2021impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
2022    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2023        *self += summary.text.bytes;
2024    }
2025}
2026
2027impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
2028    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2029        Ord::cmp(self, &cursor_location.text.bytes)
2030    }
2031}
2032
2033impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Option<&'a ExcerptId> {
2034    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2035        Ord::cmp(self, &Some(&cursor_location.excerpt_id))
2036    }
2037}
2038
2039impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
2040    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2041        *self += summary.text.lines;
2042    }
2043}
2044
2045impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
2046    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2047        *self += summary.text.lines_utf16
2048    }
2049}
2050
2051impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a ExcerptId> {
2052    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2053        *self = Some(&summary.excerpt_id);
2054    }
2055}
2056
2057impl<'a> MultiBufferRows<'a> {
2058    pub fn seek(&mut self, row: u32) {
2059        self.buffer_row_range = 0..0;
2060
2061        self.excerpts
2062            .seek_forward(&Point::new(row, 0), Bias::Right, &());
2063        if self.excerpts.item().is_none() {
2064            self.excerpts.prev(&());
2065
2066            if self.excerpts.item().is_none() && row == 0 {
2067                self.buffer_row_range = 0..1;
2068                return;
2069            }
2070        }
2071
2072        if let Some(excerpt) = self.excerpts.item() {
2073            let overshoot = row - self.excerpts.start().row;
2074            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer).row;
2075            self.buffer_row_range.start = excerpt_start + overshoot;
2076            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
2077        }
2078    }
2079}
2080
2081impl<'a> Iterator for MultiBufferRows<'a> {
2082    type Item = Option<u32>;
2083
2084    fn next(&mut self) -> Option<Self::Item> {
2085        loop {
2086            if !self.buffer_row_range.is_empty() {
2087                let row = Some(self.buffer_row_range.start);
2088                self.buffer_row_range.start += 1;
2089                return Some(row);
2090            }
2091            self.excerpts.item()?;
2092            self.excerpts.next(&());
2093            let excerpt = self.excerpts.item()?;
2094            self.buffer_row_range.start = excerpt.range.start.to_point(&excerpt.buffer).row;
2095            self.buffer_row_range.end =
2096                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
2097        }
2098    }
2099}
2100
2101impl<'a> MultiBufferChunks<'a> {
2102    pub fn offset(&self) -> usize {
2103        self.range.start
2104    }
2105
2106    pub fn seek(&mut self, offset: usize) {
2107        self.range.start = offset;
2108        self.excerpts.seek(&offset, Bias::Right, &());
2109        if let Some(excerpt) = self.excerpts.item() {
2110            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2111                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
2112                self.theme,
2113            ));
2114        } else {
2115            self.excerpt_chunks = None;
2116        }
2117    }
2118}
2119
2120impl<'a> Iterator for MultiBufferChunks<'a> {
2121    type Item = Chunk<'a>;
2122
2123    fn next(&mut self) -> Option<Self::Item> {
2124        if self.range.is_empty() {
2125            None
2126        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
2127            self.range.start += chunk.text.len();
2128            Some(chunk)
2129        } else {
2130            self.excerpts.next(&());
2131            let excerpt = self.excerpts.item()?;
2132            self.excerpt_chunks = Some(
2133                excerpt.chunks_in_range(0..self.range.end - self.excerpts.start(), self.theme),
2134            );
2135            self.next()
2136        }
2137    }
2138}
2139
2140impl<'a> MultiBufferBytes<'a> {
2141    fn consume(&mut self, len: usize) {
2142        self.range.start += len;
2143        self.chunk = &self.chunk[len..];
2144
2145        if !self.range.is_empty() && self.chunk.is_empty() {
2146            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
2147                self.chunk = chunk;
2148            } else {
2149                self.excerpts.next(&());
2150                if let Some(excerpt) = self.excerpts.item() {
2151                    let mut excerpt_bytes =
2152                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
2153                    self.chunk = excerpt_bytes.next().unwrap();
2154                    self.excerpt_bytes = Some(excerpt_bytes);
2155                }
2156            }
2157        }
2158    }
2159}
2160
2161impl<'a> Iterator for MultiBufferBytes<'a> {
2162    type Item = &'a [u8];
2163
2164    fn next(&mut self) -> Option<Self::Item> {
2165        let chunk = self.chunk;
2166        if chunk.is_empty() {
2167            None
2168        } else {
2169            self.consume(chunk.len());
2170            Some(chunk)
2171        }
2172    }
2173}
2174
2175impl<'a> io::Read for MultiBufferBytes<'a> {
2176    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
2177        let len = cmp::min(buf.len(), self.chunk.len());
2178        buf[..len].copy_from_slice(&self.chunk[..len]);
2179        if len > 0 {
2180            self.consume(len);
2181        }
2182        Ok(len)
2183    }
2184}
2185
2186impl<'a> Iterator for ExcerptBytes<'a> {
2187    type Item = &'a [u8];
2188
2189    fn next(&mut self) -> Option<Self::Item> {
2190        if let Some(chunk) = self.content_bytes.next() {
2191            if !chunk.is_empty() {
2192                return Some(chunk);
2193            }
2194        }
2195
2196        if self.footer_height > 0 {
2197            let result = &NEWLINES[..self.footer_height];
2198            self.footer_height = 0;
2199            return Some(result);
2200        }
2201
2202        None
2203    }
2204}
2205
2206impl<'a> Iterator for ExcerptChunks<'a> {
2207    type Item = Chunk<'a>;
2208
2209    fn next(&mut self) -> Option<Self::Item> {
2210        if let Some(chunk) = self.content_chunks.next() {
2211            return Some(chunk);
2212        }
2213
2214        if self.footer_height > 0 {
2215            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
2216            self.footer_height = 0;
2217            return Some(Chunk {
2218                text,
2219                ..Default::default()
2220            });
2221        }
2222
2223        None
2224    }
2225}
2226
2227impl ToOffset for Point {
2228    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2229        snapshot.point_to_offset(*self)
2230    }
2231}
2232
2233impl ToOffset for PointUtf16 {
2234    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2235        snapshot.point_utf16_to_offset(*self)
2236    }
2237}
2238
2239impl ToOffset for usize {
2240    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2241        assert!(*self <= snapshot.len(), "offset is out of range");
2242        *self
2243    }
2244}
2245
2246impl ToPoint for usize {
2247    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
2248        snapshot.offset_to_point(*self)
2249    }
2250}
2251
2252impl ToPoint for Point {
2253    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
2254        *self
2255    }
2256}
2257
2258#[cfg(test)]
2259mod tests {
2260    use super::*;
2261    use gpui::MutableAppContext;
2262    use language::{Buffer, Rope};
2263    use rand::prelude::*;
2264    use std::env;
2265    use text::{Point, RandomCharIter};
2266    use util::test::sample_text;
2267
2268    #[gpui::test]
2269    fn test_singleton_multibuffer(cx: &mut MutableAppContext) {
2270        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2271        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
2272
2273        let snapshot = multibuffer.read(cx).snapshot(cx);
2274        assert_eq!(snapshot.text(), buffer.read(cx).text());
2275
2276        assert_eq!(
2277            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2278            (0..buffer.read(cx).row_count())
2279                .map(Some)
2280                .collect::<Vec<_>>()
2281        );
2282
2283        buffer.update(cx, |buffer, cx| buffer.edit([1..3], "XXX\n", cx));
2284        let snapshot = multibuffer.read(cx).snapshot(cx);
2285
2286        assert_eq!(snapshot.text(), buffer.read(cx).text());
2287        assert_eq!(
2288            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2289            (0..buffer.read(cx).row_count())
2290                .map(Some)
2291                .collect::<Vec<_>>()
2292        );
2293    }
2294
2295    #[gpui::test]
2296    fn test_remote_multibuffer(cx: &mut MutableAppContext) {
2297        let host_buffer = cx.add_model(|cx| Buffer::new(0, "a", cx));
2298        let guest_buffer = cx.add_model(|cx| {
2299            let message = host_buffer.read(cx).to_proto();
2300            Buffer::from_proto(1, message, None, cx).unwrap()
2301        });
2302        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
2303        let snapshot = multibuffer.read(cx).snapshot(cx);
2304        assert_eq!(snapshot.text(), "a");
2305
2306        guest_buffer.update(cx, |buffer, cx| buffer.edit([1..1], "b", cx));
2307        let snapshot = multibuffer.read(cx).snapshot(cx);
2308        assert_eq!(snapshot.text(), "ab");
2309
2310        guest_buffer.update(cx, |buffer, cx| buffer.edit([2..2], "c", cx));
2311        let snapshot = multibuffer.read(cx).snapshot(cx);
2312        assert_eq!(snapshot.text(), "abc");
2313    }
2314
2315    #[gpui::test]
2316    fn test_excerpt_buffer(cx: &mut MutableAppContext) {
2317        let buffer_1 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2318        let buffer_2 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'g'), cx));
2319        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2320
2321        let subscription = multibuffer.update(cx, |multibuffer, cx| {
2322            let subscription = multibuffer.subscribe();
2323            multibuffer.push_excerpt(
2324                ExcerptProperties {
2325                    buffer: &buffer_1,
2326                    range: Point::new(1, 2)..Point::new(2, 5),
2327                },
2328                cx,
2329            );
2330            assert_eq!(
2331                subscription.consume().into_inner(),
2332                [Edit {
2333                    old: 0..0,
2334                    new: 0..10
2335                }]
2336            );
2337
2338            multibuffer.push_excerpt(
2339                ExcerptProperties {
2340                    buffer: &buffer_1,
2341                    range: Point::new(3, 3)..Point::new(4, 4),
2342                },
2343                cx,
2344            );
2345            multibuffer.push_excerpt(
2346                ExcerptProperties {
2347                    buffer: &buffer_2,
2348                    range: Point::new(3, 1)..Point::new(3, 3),
2349                },
2350                cx,
2351            );
2352            assert_eq!(
2353                subscription.consume().into_inner(),
2354                [Edit {
2355                    old: 10..10,
2356                    new: 10..22
2357                }]
2358            );
2359
2360            subscription
2361        });
2362
2363        let snapshot = multibuffer.read(cx).snapshot(cx);
2364        assert_eq!(
2365            snapshot.text(),
2366            concat!(
2367                "bbbb\n",  // Preserve newlines
2368                "ccccc\n", //
2369                "ddd\n",   //
2370                "eeee\n",  //
2371                "jj"       //
2372            )
2373        );
2374        assert_eq!(
2375            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2376            [Some(1), Some(2), Some(3), Some(4), Some(3)]
2377        );
2378        assert_eq!(
2379            snapshot.buffer_rows(2).collect::<Vec<_>>(),
2380            [Some(3), Some(4), Some(3)]
2381        );
2382        assert_eq!(snapshot.buffer_rows(4).collect::<Vec<_>>(), [Some(3)]);
2383        assert_eq!(snapshot.buffer_rows(5).collect::<Vec<_>>(), []);
2384        assert!(!snapshot.range_contains_excerpt_boundary(Point::new(1, 0)..Point::new(1, 5)));
2385        assert!(snapshot.range_contains_excerpt_boundary(Point::new(1, 0)..Point::new(2, 0)));
2386        assert!(snapshot.range_contains_excerpt_boundary(Point::new(1, 0)..Point::new(4, 0)));
2387        assert!(!snapshot.range_contains_excerpt_boundary(Point::new(2, 0)..Point::new(3, 0)));
2388        assert!(!snapshot.range_contains_excerpt_boundary(Point::new(4, 0)..Point::new(4, 2)));
2389        assert!(!snapshot.range_contains_excerpt_boundary(Point::new(4, 2)..Point::new(4, 2)));
2390
2391        buffer_1.update(cx, |buffer, cx| {
2392            buffer.edit(
2393                [
2394                    Point::new(0, 0)..Point::new(0, 0),
2395                    Point::new(2, 1)..Point::new(2, 3),
2396                ],
2397                "\n",
2398                cx,
2399            );
2400        });
2401
2402        let snapshot = multibuffer.read(cx).snapshot(cx);
2403        assert_eq!(
2404            snapshot.text(),
2405            concat!(
2406                "bbbb\n", // Preserve newlines
2407                "c\n",    //
2408                "cc\n",   //
2409                "ddd\n",  //
2410                "eeee\n", //
2411                "jj"      //
2412            )
2413        );
2414
2415        assert_eq!(
2416            subscription.consume().into_inner(),
2417            [Edit {
2418                old: 6..8,
2419                new: 6..7
2420            }]
2421        );
2422
2423        let snapshot = multibuffer.read(cx).snapshot(cx);
2424        assert_eq!(
2425            snapshot.clip_point(Point::new(0, 5), Bias::Left),
2426            Point::new(0, 4)
2427        );
2428        assert_eq!(
2429            snapshot.clip_point(Point::new(0, 5), Bias::Right),
2430            Point::new(0, 4)
2431        );
2432        assert_eq!(
2433            snapshot.clip_point(Point::new(5, 1), Bias::Right),
2434            Point::new(5, 1)
2435        );
2436        assert_eq!(
2437            snapshot.clip_point(Point::new(5, 2), Bias::Right),
2438            Point::new(5, 2)
2439        );
2440        assert_eq!(
2441            snapshot.clip_point(Point::new(5, 3), Bias::Right),
2442            Point::new(5, 2)
2443        );
2444
2445        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
2446            let buffer_2_excerpt_id = multibuffer.excerpt_ids_for_buffer(&buffer_2)[0].clone();
2447            multibuffer.remove_excerpts(&[buffer_2_excerpt_id], cx);
2448            multibuffer.snapshot(cx)
2449        });
2450
2451        assert_eq!(
2452            snapshot.text(),
2453            concat!(
2454                "bbbb\n", // Preserve newlines
2455                "c\n",    //
2456                "cc\n",   //
2457                "ddd\n",  //
2458                "eeee",   //
2459            )
2460        );
2461    }
2462
2463    #[gpui::test]
2464    fn test_empty_excerpt_buffer(cx: &mut MutableAppContext) {
2465        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2466
2467        let snapshot = multibuffer.read(cx).snapshot(cx);
2468        assert_eq!(snapshot.text(), "");
2469        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), &[Some(0)]);
2470        assert_eq!(snapshot.buffer_rows(1).collect::<Vec<_>>(), &[]);
2471    }
2472
2473    #[gpui::test]
2474    fn test_singleton_multibuffer_anchors(cx: &mut MutableAppContext) {
2475        let buffer = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
2476        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
2477        let old_snapshot = multibuffer.read(cx).snapshot(cx);
2478        buffer.update(cx, |buffer, cx| {
2479            buffer.edit([0..0], "X", cx);
2480            buffer.edit([5..5], "Y", cx);
2481        });
2482        let new_snapshot = multibuffer.read(cx).snapshot(cx);
2483
2484        assert_eq!(old_snapshot.text(), "abcd");
2485        assert_eq!(new_snapshot.text(), "XabcdY");
2486
2487        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
2488        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
2489        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
2490        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
2491    }
2492
2493    #[gpui::test]
2494    fn test_multibuffer_anchors(cx: &mut MutableAppContext) {
2495        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
2496        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "efghi", cx));
2497        let multibuffer = cx.add_model(|cx| {
2498            let mut multibuffer = MultiBuffer::new(0);
2499            multibuffer.push_excerpt(
2500                ExcerptProperties {
2501                    buffer: &buffer_1,
2502                    range: 0..4,
2503                },
2504                cx,
2505            );
2506            multibuffer.push_excerpt(
2507                ExcerptProperties {
2508                    buffer: &buffer_2,
2509                    range: 0..5,
2510                },
2511                cx,
2512            );
2513            multibuffer
2514        });
2515        let old_snapshot = multibuffer.read(cx).snapshot(cx);
2516
2517        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
2518        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
2519        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
2520        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
2521        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
2522        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
2523
2524        buffer_1.update(cx, |buffer, cx| {
2525            buffer.edit([0..0], "W", cx);
2526            buffer.edit([5..5], "X", cx);
2527        });
2528        buffer_2.update(cx, |buffer, cx| {
2529            buffer.edit([0..0], "Y", cx);
2530            buffer.edit([6..0], "Z", cx);
2531        });
2532        let new_snapshot = multibuffer.read(cx).snapshot(cx);
2533
2534        assert_eq!(old_snapshot.text(), "abcd\nefghi");
2535        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
2536
2537        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
2538        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
2539        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
2540        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
2541        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
2542        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
2543        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
2544        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
2545        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
2546        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
2547    }
2548
2549    #[gpui::test]
2550    fn test_multibuffer_resolving_anchors_after_replacing_their_excerpts(
2551        cx: &mut MutableAppContext,
2552    ) {
2553        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
2554        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "ABCDEFGHIJKLMNOP", cx));
2555        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2556
2557        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
2558        // Add an excerpt from buffer 1 that spans this new insertion.
2559        buffer_1.update(cx, |buffer, cx| buffer.edit([4..4], "123", cx));
2560        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
2561            multibuffer.push_excerpt(
2562                ExcerptProperties {
2563                    buffer: &buffer_1,
2564                    range: 0..7,
2565                },
2566                cx,
2567            )
2568        });
2569
2570        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
2571        assert_eq!(snapshot_1.text(), "abcd123");
2572
2573        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
2574        let (excerpt_id_2, excerpt_id_3, _) = multibuffer.update(cx, |multibuffer, cx| {
2575            multibuffer.remove_excerpts([&excerpt_id_1], cx);
2576            (
2577                multibuffer.push_excerpt(
2578                    ExcerptProperties {
2579                        buffer: &buffer_2,
2580                        range: 0..4,
2581                    },
2582                    cx,
2583                ),
2584                multibuffer.push_excerpt(
2585                    ExcerptProperties {
2586                        buffer: &buffer_2,
2587                        range: 6..10,
2588                    },
2589                    cx,
2590                ),
2591                multibuffer.push_excerpt(
2592                    ExcerptProperties {
2593                        buffer: &buffer_2,
2594                        range: 12..16,
2595                    },
2596                    cx,
2597                ),
2598            )
2599        });
2600        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
2601        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
2602
2603        // The old excerpt id has been reused.
2604        assert_eq!(excerpt_id_2, excerpt_id_1);
2605
2606        // Resolve some anchors from the previous snapshot in the new snapshot.
2607        // Although there is still an excerpt with the same id, it is for
2608        // a different buffer, so we don't attempt to resolve the old text
2609        // anchor in the new buffer.
2610        assert_eq!(
2611            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
2612            0
2613        );
2614        assert_eq!(
2615            snapshot_2.summaries_for_anchors::<usize, _>(&[
2616                snapshot_1.anchor_before(2),
2617                snapshot_1.anchor_after(3)
2618            ]),
2619            vec![0, 0]
2620        );
2621        let refresh =
2622            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
2623        assert_eq!(
2624            refresh,
2625            &[
2626                (0, snapshot_2.anchor_before(0), false),
2627                (1, snapshot_2.anchor_after(0), false),
2628            ]
2629        );
2630
2631        // Replace the middle excerpt with a smaller excerpt in buffer 2,
2632        // that intersects the old excerpt.
2633        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
2634            multibuffer.remove_excerpts([&excerpt_id_3], cx);
2635            multibuffer.insert_excerpt_after(
2636                &excerpt_id_3,
2637                ExcerptProperties {
2638                    buffer: &buffer_2,
2639                    range: 5..8,
2640                },
2641                cx,
2642            )
2643        });
2644
2645        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
2646        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
2647        assert_ne!(excerpt_id_5, excerpt_id_3);
2648
2649        // Resolve some anchors from the previous snapshot in the new snapshot.
2650        // The anchor in the middle excerpt snaps to the beginning of the
2651        // excerpt, since it is not
2652        let anchors = [
2653            snapshot_2.anchor_before(0),
2654            snapshot_2.anchor_after(2),
2655            snapshot_2.anchor_after(6),
2656            snapshot_2.anchor_after(14),
2657        ];
2658        assert_eq!(
2659            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
2660            &[0, 2, 9, 13]
2661        );
2662
2663        let new_anchors = snapshot_3.refresh_anchors(&anchors);
2664        assert_eq!(
2665            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
2666            &[(0, true), (1, true), (2, true), (3, true)]
2667        );
2668        assert_eq!(
2669            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
2670            &[0, 2, 7, 13]
2671        );
2672    }
2673
2674    #[gpui::test(iterations = 100)]
2675    fn test_random_multibuffer(cx: &mut MutableAppContext, mut rng: StdRng) {
2676        let operations = env::var("OPERATIONS")
2677            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
2678            .unwrap_or(10);
2679
2680        let mut buffers: Vec<ModelHandle<Buffer>> = Vec::new();
2681        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2682        let mut excerpt_ids = Vec::new();
2683        let mut expected_excerpts = Vec::<(ModelHandle<Buffer>, Range<text::Anchor>)>::new();
2684        let mut anchors = Vec::new();
2685        let mut old_versions = Vec::new();
2686
2687        for _ in 0..operations {
2688            match rng.gen_range(0..100) {
2689                0..=19 if !buffers.is_empty() => {
2690                    let buffer = buffers.choose(&mut rng).unwrap();
2691                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
2692                }
2693                20..=29 if !expected_excerpts.is_empty() => {
2694                    let mut ids_to_remove = vec![];
2695                    for _ in 0..rng.gen_range(1..=3) {
2696                        if expected_excerpts.is_empty() {
2697                            break;
2698                        }
2699
2700                        let ix = rng.gen_range(0..expected_excerpts.len());
2701                        ids_to_remove.push(excerpt_ids.remove(ix));
2702                        let (buffer, range) = expected_excerpts.remove(ix);
2703                        let buffer = buffer.read(cx);
2704                        log::info!(
2705                            "Removing excerpt {}: {:?}",
2706                            ix,
2707                            buffer
2708                                .text_for_range(range.to_offset(&buffer))
2709                                .collect::<String>(),
2710                        );
2711                    }
2712                    ids_to_remove.sort_unstable();
2713                    multibuffer.update(cx, |multibuffer, cx| {
2714                        multibuffer.remove_excerpts(&ids_to_remove, cx)
2715                    });
2716                }
2717                30..=39 if !expected_excerpts.is_empty() => {
2718                    let multibuffer = multibuffer.read(cx).read(cx);
2719                    let offset =
2720                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
2721                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
2722                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
2723                    anchors.push(multibuffer.anchor_at(offset, bias));
2724                    anchors.sort_by(|a, b| a.cmp(&b, &multibuffer).unwrap());
2725                }
2726                40..=44 if !anchors.is_empty() => {
2727                    let multibuffer = multibuffer.read(cx).read(cx);
2728                    anchors = multibuffer
2729                        .refresh_anchors(&anchors)
2730                        .into_iter()
2731                        .map(|a| a.1)
2732                        .collect();
2733                }
2734                _ => {
2735                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
2736                        let base_text = RandomCharIter::new(&mut rng).take(10).collect::<String>();
2737                        buffers.push(cx.add_model(|cx| Buffer::new(0, base_text, cx)));
2738                        buffers.last().unwrap()
2739                    } else {
2740                        buffers.choose(&mut rng).unwrap()
2741                    };
2742
2743                    let buffer = buffer_handle.read(cx);
2744                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
2745                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
2746                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
2747                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
2748                    let prev_excerpt_id = excerpt_ids
2749                        .get(prev_excerpt_ix)
2750                        .cloned()
2751                        .unwrap_or(ExcerptId::max());
2752                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
2753
2754                    log::info!(
2755                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
2756                        excerpt_ix,
2757                        expected_excerpts.len(),
2758                        buffer_handle.id(),
2759                        buffer.text(),
2760                        start_ix..end_ix,
2761                        &buffer.text()[start_ix..end_ix]
2762                    );
2763
2764                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
2765                        multibuffer.insert_excerpt_after(
2766                            &prev_excerpt_id,
2767                            ExcerptProperties {
2768                                buffer: &buffer_handle,
2769                                range: start_ix..end_ix,
2770                            },
2771                            cx,
2772                        )
2773                    });
2774
2775                    excerpt_ids.insert(excerpt_ix, excerpt_id);
2776                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
2777                }
2778            }
2779
2780            if rng.gen_bool(0.3) {
2781                multibuffer.update(cx, |multibuffer, cx| {
2782                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
2783                })
2784            }
2785
2786            let snapshot = multibuffer.read(cx).snapshot(cx);
2787
2788            let mut excerpt_starts = Vec::new();
2789            let mut expected_text = String::new();
2790            let mut expected_buffer_rows = Vec::new();
2791            for (buffer, range) in &expected_excerpts {
2792                let buffer = buffer.read(cx);
2793                let buffer_range = range.to_offset(buffer);
2794
2795                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
2796                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
2797                expected_text.push('\n');
2798
2799                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
2800                    ..=buffer.offset_to_point(buffer_range.end).row;
2801                for row in buffer_row_range {
2802                    expected_buffer_rows.push(Some(row));
2803                }
2804            }
2805            // Remove final trailing newline.
2806            if !expected_excerpts.is_empty() {
2807                expected_text.pop();
2808            }
2809
2810            // Always report one buffer row
2811            if expected_buffer_rows.is_empty() {
2812                expected_buffer_rows.push(Some(0));
2813            }
2814
2815            assert_eq!(snapshot.text(), expected_text);
2816            log::info!("MultiBuffer text: {:?}", expected_text);
2817
2818            assert_eq!(
2819                snapshot.buffer_rows(0).collect::<Vec<_>>(),
2820                expected_buffer_rows,
2821            );
2822
2823            for _ in 0..5 {
2824                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
2825                assert_eq!(
2826                    snapshot.buffer_rows(start_row as u32).collect::<Vec<_>>(),
2827                    &expected_buffer_rows[start_row..],
2828                    "buffer_rows({})",
2829                    start_row
2830                );
2831            }
2832
2833            assert_eq!(
2834                snapshot.max_buffer_row(),
2835                expected_buffer_rows
2836                    .into_iter()
2837                    .filter_map(|r| r)
2838                    .max()
2839                    .unwrap()
2840            );
2841
2842            let mut excerpt_starts = excerpt_starts.into_iter();
2843            for (buffer, range) in &expected_excerpts {
2844                let buffer_id = buffer.id();
2845                let buffer = buffer.read(cx);
2846                let buffer_range = range.to_offset(buffer);
2847                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
2848                let buffer_start_point_utf16 =
2849                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
2850
2851                let excerpt_start = excerpt_starts.next().unwrap();
2852                let mut offset = excerpt_start.bytes;
2853                let mut buffer_offset = buffer_range.start;
2854                let mut point = excerpt_start.lines;
2855                let mut buffer_point = buffer_start_point;
2856                let mut point_utf16 = excerpt_start.lines_utf16;
2857                let mut buffer_point_utf16 = buffer_start_point_utf16;
2858                for ch in buffer
2859                    .snapshot()
2860                    .chunks(buffer_range.clone(), None)
2861                    .flat_map(|c| c.text.chars())
2862                {
2863                    for _ in 0..ch.len_utf8() {
2864                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
2865                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
2866                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
2867                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
2868                        assert_eq!(
2869                            left_offset,
2870                            excerpt_start.bytes + (buffer_left_offset - buffer_range.start),
2871                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
2872                            offset,
2873                            buffer_id,
2874                            buffer_offset,
2875                        );
2876                        assert_eq!(
2877                            right_offset,
2878                            excerpt_start.bytes + (buffer_right_offset - buffer_range.start),
2879                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
2880                            offset,
2881                            buffer_id,
2882                            buffer_offset,
2883                        );
2884
2885                        let left_point = snapshot.clip_point(point, Bias::Left);
2886                        let right_point = snapshot.clip_point(point, Bias::Right);
2887                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
2888                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
2889                        assert_eq!(
2890                            left_point,
2891                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
2892                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
2893                            point,
2894                            buffer_id,
2895                            buffer_point,
2896                        );
2897                        assert_eq!(
2898                            right_point,
2899                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
2900                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
2901                            point,
2902                            buffer_id,
2903                            buffer_point,
2904                        );
2905
2906                        assert_eq!(
2907                            snapshot.point_to_offset(left_point),
2908                            left_offset,
2909                            "point_to_offset({:?})",
2910                            left_point,
2911                        );
2912                        assert_eq!(
2913                            snapshot.offset_to_point(left_offset),
2914                            left_point,
2915                            "offset_to_point({:?})",
2916                            left_offset,
2917                        );
2918
2919                        offset += 1;
2920                        buffer_offset += 1;
2921                        if ch == '\n' {
2922                            point += Point::new(1, 0);
2923                            buffer_point += Point::new(1, 0);
2924                        } else {
2925                            point += Point::new(0, 1);
2926                            buffer_point += Point::new(0, 1);
2927                        }
2928                    }
2929
2930                    for _ in 0..ch.len_utf16() {
2931                        let left_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Left);
2932                        let right_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Right);
2933                        let buffer_left_point_utf16 =
2934                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Left);
2935                        let buffer_right_point_utf16 =
2936                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Right);
2937                        assert_eq!(
2938                            left_point_utf16,
2939                            excerpt_start.lines_utf16
2940                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
2941                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
2942                            point_utf16,
2943                            buffer_id,
2944                            buffer_point_utf16,
2945                        );
2946                        assert_eq!(
2947                            right_point_utf16,
2948                            excerpt_start.lines_utf16
2949                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
2950                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
2951                            point_utf16,
2952                            buffer_id,
2953                            buffer_point_utf16,
2954                        );
2955
2956                        if ch == '\n' {
2957                            point_utf16 += PointUtf16::new(1, 0);
2958                            buffer_point_utf16 += PointUtf16::new(1, 0);
2959                        } else {
2960                            point_utf16 += PointUtf16::new(0, 1);
2961                            buffer_point_utf16 += PointUtf16::new(0, 1);
2962                        }
2963                    }
2964                }
2965            }
2966
2967            for (row, line) in expected_text.split('\n').enumerate() {
2968                assert_eq!(
2969                    snapshot.line_len(row as u32),
2970                    line.len() as u32,
2971                    "line_len({}).",
2972                    row
2973                );
2974            }
2975
2976            let text_rope = Rope::from(expected_text.as_str());
2977            for _ in 0..10 {
2978                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
2979                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
2980
2981                let text_for_range = snapshot
2982                    .text_for_range(start_ix..end_ix)
2983                    .collect::<String>();
2984                assert_eq!(
2985                    text_for_range,
2986                    &expected_text[start_ix..end_ix],
2987                    "incorrect text for range {:?}",
2988                    start_ix..end_ix
2989                );
2990
2991                let excerpted_buffer_ranges =
2992                    multibuffer.read(cx).excerpted_buffers(start_ix..end_ix, cx);
2993                let excerpted_buffers_text = excerpted_buffer_ranges
2994                    .into_iter()
2995                    .map(|(buffer, buffer_range)| {
2996                        buffer
2997                            .read(cx)
2998                            .text_for_range(buffer_range)
2999                            .collect::<String>()
3000                    })
3001                    .collect::<Vec<_>>()
3002                    .join("\n");
3003                assert_eq!(excerpted_buffers_text, text_for_range);
3004
3005                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
3006                assert_eq!(
3007                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
3008                    expected_summary,
3009                    "incorrect summary for range {:?}",
3010                    start_ix..end_ix
3011                );
3012            }
3013
3014            // Anchor resolution
3015            for (anchor, resolved_offset) in anchors
3016                .iter()
3017                .zip(snapshot.summaries_for_anchors::<usize, _>(&anchors))
3018            {
3019                assert_eq!(
3020                    snapshot.summary_for_anchor::<usize>(anchor),
3021                    resolved_offset
3022                );
3023            }
3024
3025            for _ in 0..10 {
3026                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3027                assert_eq!(
3028                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
3029                    expected_text[..end_ix].chars().rev().collect::<String>(),
3030                );
3031            }
3032
3033            for _ in 0..10 {
3034                let end_ix = rng.gen_range(0..=text_rope.len());
3035                let start_ix = rng.gen_range(0..=end_ix);
3036                assert_eq!(
3037                    snapshot
3038                        .bytes_in_range(start_ix..end_ix)
3039                        .flatten()
3040                        .copied()
3041                        .collect::<Vec<_>>(),
3042                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
3043                    "bytes_in_range({:?})",
3044                    start_ix..end_ix,
3045                );
3046            }
3047        }
3048
3049        let snapshot = multibuffer.read(cx).snapshot(cx);
3050        for (old_snapshot, subscription) in old_versions {
3051            let edits = subscription.consume().into_inner();
3052
3053            log::info!(
3054                "applying subscription edits to old text: {:?}: {:?}",
3055                old_snapshot.text(),
3056                edits,
3057            );
3058
3059            let mut text = old_snapshot.text();
3060            for edit in edits {
3061                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
3062                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
3063            }
3064            assert_eq!(text.to_string(), snapshot.text());
3065        }
3066    }
3067
3068    #[gpui::test]
3069    fn test_history(cx: &mut MutableAppContext) {
3070        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "1234", cx));
3071        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "5678", cx));
3072        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3073        let group_interval = multibuffer.read(cx).history.group_interval;
3074        multibuffer.update(cx, |multibuffer, cx| {
3075            multibuffer.push_excerpt(
3076                ExcerptProperties {
3077                    buffer: &buffer_1,
3078                    range: 0..buffer_1.read(cx).len(),
3079                },
3080                cx,
3081            );
3082            multibuffer.push_excerpt(
3083                ExcerptProperties {
3084                    buffer: &buffer_2,
3085                    range: 0..buffer_2.read(cx).len(),
3086                },
3087                cx,
3088            );
3089        });
3090
3091        let mut now = Instant::now();
3092
3093        multibuffer.update(cx, |multibuffer, cx| {
3094            multibuffer.start_transaction_at(now, cx);
3095            multibuffer.edit(
3096                [
3097                    Point::new(0, 0)..Point::new(0, 0),
3098                    Point::new(1, 0)..Point::new(1, 0),
3099                ],
3100                "A",
3101                cx,
3102            );
3103            multibuffer.edit(
3104                [
3105                    Point::new(0, 1)..Point::new(0, 1),
3106                    Point::new(1, 1)..Point::new(1, 1),
3107                ],
3108                "B",
3109                cx,
3110            );
3111            multibuffer.end_transaction_at(now, cx);
3112            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3113
3114            now += 2 * group_interval;
3115            multibuffer.start_transaction_at(now, cx);
3116            multibuffer.edit([2..2], "C", cx);
3117            multibuffer.end_transaction_at(now, cx);
3118            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3119
3120            multibuffer.undo(cx);
3121            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3122
3123            multibuffer.undo(cx);
3124            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3125
3126            multibuffer.redo(cx);
3127            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3128
3129            multibuffer.redo(cx);
3130            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3131
3132            buffer_1.update(cx, |buffer_1, cx| buffer_1.undo(cx));
3133            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3134
3135            multibuffer.undo(cx);
3136            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3137
3138            multibuffer.redo(cx);
3139            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3140
3141            multibuffer.redo(cx);
3142            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3143
3144            multibuffer.undo(cx);
3145            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3146
3147            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
3148            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3149
3150            multibuffer.undo(cx);
3151            assert_eq!(multibuffer.read(cx).text(), "C1234\n5678");
3152        });
3153    }
3154}