multi_buffer.rs

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