multi_buffer.rs

   1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt};
   4use anyhow::Result;
   5use clock::ReplicaId;
   6use collections::{Bound, HashMap, HashSet};
   7use gpui::{AppContext, Entity, ModelContext, ModelHandle, Task};
   8pub use language::Completion;
   9use language::{
  10    Buffer, BufferChunks, BufferSnapshot, Chunk, DiagnosticEntry, Event, File, Language, Outline,
  11    OutlineItem, Selection, ToOffset as _, ToPoint as _, ToPointUtf16 as _, TransactionId,
  12};
  13use std::{
  14    cell::{Ref, RefCell},
  15    cmp, fmt, io,
  16    iter::{self, FromIterator},
  17    ops::{Range, RangeBounds, Sub},
  18    str,
  19    sync::Arc,
  20    time::{Duration, Instant},
  21};
  22use sum_tree::{Bias, Cursor, SumTree};
  23use text::{
  24    locator::Locator,
  25    rope::TextDimension,
  26    subscription::{Subscription, Topic},
  27    AnchorRangeExt as _, Edit, Point, PointUtf16, TextSummary,
  28};
  29use theme::SyntaxTheme;
  30
  31const NEWLINES: &'static [u8] = &[b'\n'; u8::MAX as usize];
  32
  33pub type ExcerptId = Locator;
  34
  35pub struct MultiBuffer {
  36    snapshot: RefCell<MultiBufferSnapshot>,
  37    buffers: RefCell<HashMap<usize, BufferState>>,
  38    subscriptions: Topic,
  39    singleton: bool,
  40    replica_id: ReplicaId,
  41    history: History,
  42}
  43
  44struct History {
  45    next_transaction_id: TransactionId,
  46    undo_stack: Vec<Transaction>,
  47    redo_stack: Vec<Transaction>,
  48    transaction_depth: usize,
  49    group_interval: Duration,
  50}
  51
  52#[derive(Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Debug)]
  53pub enum CharKind {
  54    Newline,
  55    Punctuation,
  56    Whitespace,
  57    Word,
  58}
  59
  60struct Transaction {
  61    id: TransactionId,
  62    buffer_transactions: HashSet<(usize, text::TransactionId)>,
  63    first_edit_at: Instant,
  64    last_edit_at: Instant,
  65}
  66
  67pub trait ToOffset: 'static + fmt::Debug {
  68    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
  69}
  70
  71pub trait ToPoint: 'static + fmt::Debug {
  72    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
  73}
  74
  75pub trait ToPointUtf16: 'static + fmt::Debug {
  76    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
  77}
  78
  79struct BufferState {
  80    buffer: ModelHandle<Buffer>,
  81    last_version: clock::Global,
  82    last_parse_count: usize,
  83    last_selections_update_count: usize,
  84    last_diagnostics_update_count: usize,
  85    last_file_update_count: usize,
  86    excerpts: Vec<ExcerptId>,
  87    _subscriptions: [gpui::Subscription; 2],
  88}
  89
  90#[derive(Clone, Default)]
  91pub struct MultiBufferSnapshot {
  92    singleton: bool,
  93    excerpts: SumTree<Excerpt>,
  94    parse_count: usize,
  95    diagnostics_update_count: usize,
  96    trailing_excerpt_update_count: usize,
  97    is_dirty: bool,
  98    has_conflict: bool,
  99}
 100
 101pub struct ExcerptBoundary {
 102    pub row: u32,
 103    pub buffer: BufferSnapshot,
 104    pub range: Range<text::Anchor>,
 105    pub starts_new_buffer: bool,
 106}
 107
 108#[derive(Clone)]
 109struct Excerpt {
 110    id: ExcerptId,
 111    buffer_id: usize,
 112    buffer: BufferSnapshot,
 113    range: Range<text::Anchor>,
 114    max_buffer_row: u32,
 115    text_summary: TextSummary,
 116    has_trailing_newline: bool,
 117}
 118
 119#[derive(Clone, Debug, Default)]
 120struct ExcerptSummary {
 121    excerpt_id: ExcerptId,
 122    max_buffer_row: u32,
 123    text: TextSummary,
 124}
 125
 126pub struct MultiBufferRows<'a> {
 127    buffer_row_range: Range<u32>,
 128    excerpts: Cursor<'a, Excerpt, Point>,
 129}
 130
 131pub struct MultiBufferChunks<'a> {
 132    range: Range<usize>,
 133    excerpts: Cursor<'a, Excerpt, usize>,
 134    excerpt_chunks: Option<ExcerptChunks<'a>>,
 135    language_aware: bool,
 136}
 137
 138pub struct MultiBufferBytes<'a> {
 139    range: Range<usize>,
 140    excerpts: Cursor<'a, Excerpt, usize>,
 141    excerpt_bytes: Option<ExcerptBytes<'a>>,
 142    chunk: &'a [u8],
 143}
 144
 145struct ExcerptChunks<'a> {
 146    content_chunks: BufferChunks<'a>,
 147    footer_height: usize,
 148}
 149
 150struct ExcerptBytes<'a> {
 151    content_bytes: language::rope::Bytes<'a>,
 152    footer_height: usize,
 153}
 154
 155impl MultiBuffer {
 156    pub fn new(replica_id: ReplicaId) -> Self {
 157        Self {
 158            snapshot: Default::default(),
 159            buffers: Default::default(),
 160            subscriptions: Default::default(),
 161            singleton: false,
 162            replica_id,
 163            history: History {
 164                next_transaction_id: Default::default(),
 165                undo_stack: Default::default(),
 166                redo_stack: Default::default(),
 167                transaction_depth: 0,
 168                group_interval: Duration::from_millis(300),
 169            },
 170        }
 171    }
 172
 173    pub fn singleton(buffer: ModelHandle<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 174        let mut this = Self::new(buffer.read(cx).replica_id());
 175        this.singleton = true;
 176        this.push_excerpts(buffer, [text::Anchor::min()..text::Anchor::max()], cx);
 177        this.snapshot.borrow_mut().singleton = true;
 178        this
 179    }
 180
 181    #[cfg(any(test, feature = "test-support"))]
 182    pub fn build_simple(text: &str, cx: &mut gpui::MutableAppContext) -> ModelHandle<Self> {
 183        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
 184        cx.add_model(|cx| Self::singleton(buffer, cx))
 185    }
 186
 187    #[cfg(any(test, feature = "test-support"))]
 188    pub fn build_random(
 189        rng: &mut impl rand::Rng,
 190        cx: &mut gpui::MutableAppContext,
 191    ) -> ModelHandle<Self> {
 192        cx.add_model(|cx| {
 193            let mut multibuffer = MultiBuffer::new(0);
 194            let mutation_count = rng.gen_range(1..=5);
 195            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
 196            multibuffer
 197        })
 198    }
 199
 200    pub fn replica_id(&self) -> ReplicaId {
 201        self.replica_id
 202    }
 203
 204    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 205        self.sync(cx);
 206        self.snapshot.borrow().clone()
 207    }
 208
 209    pub fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 210        self.sync(cx);
 211        self.snapshot.borrow()
 212    }
 213
 214    pub fn as_singleton(&self) -> Option<ModelHandle<Buffer>> {
 215        if self.singleton {
 216            return Some(
 217                self.buffers
 218                    .borrow()
 219                    .values()
 220                    .next()
 221                    .unwrap()
 222                    .buffer
 223                    .clone(),
 224            );
 225        } else {
 226            None
 227        }
 228    }
 229
 230    pub fn subscribe(&mut self) -> Subscription {
 231        self.subscriptions.subscribe()
 232    }
 233
 234    pub fn edit<I, S, T>(&mut self, ranges: I, new_text: T, cx: &mut ModelContext<Self>)
 235    where
 236        I: IntoIterator<Item = Range<S>>,
 237        S: ToOffset,
 238        T: Into<String>,
 239    {
 240        self.edit_internal(ranges, new_text, false, cx)
 241    }
 242
 243    pub fn edit_with_autoindent<I, S, T>(
 244        &mut self,
 245        ranges: I,
 246        new_text: T,
 247        cx: &mut ModelContext<Self>,
 248    ) where
 249        I: IntoIterator<Item = Range<S>>,
 250        S: ToOffset,
 251        T: Into<String>,
 252    {
 253        self.edit_internal(ranges, new_text, true, cx)
 254    }
 255
 256    pub fn edit_internal<I, S, T>(
 257        &mut self,
 258        ranges_iter: I,
 259        new_text: T,
 260        autoindent: bool,
 261        cx: &mut ModelContext<Self>,
 262    ) where
 263        I: IntoIterator<Item = Range<S>>,
 264        S: ToOffset,
 265        T: Into<String>,
 266    {
 267        if self.buffers.borrow().is_empty() {
 268            return;
 269        }
 270
 271        if let Some(buffer) = self.as_singleton() {
 272            let snapshot = self.read(cx);
 273            let ranges = ranges_iter
 274                .into_iter()
 275                .map(|range| range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot));
 276            return buffer.update(cx, |buffer, cx| {
 277                if autoindent {
 278                    buffer.edit_with_autoindent(ranges, new_text, cx);
 279                } else {
 280                    buffer.edit(ranges, new_text, cx);
 281                }
 282            });
 283        }
 284
 285        let snapshot = self.read(cx);
 286        let mut buffer_edits: HashMap<usize, Vec<(Range<usize>, bool)>> = Default::default();
 287        let mut cursor = snapshot.excerpts.cursor::<usize>();
 288        for range in ranges_iter {
 289            let start = range.start.to_offset(&snapshot);
 290            let end = range.end.to_offset(&snapshot);
 291            cursor.seek(&start, Bias::Right, &());
 292            if cursor.item().is_none() && start == *cursor.start() {
 293                cursor.prev(&());
 294            }
 295            let start_excerpt = cursor.item().expect("start offset out of bounds");
 296            let start_overshoot = start - cursor.start();
 297            let buffer_start =
 298                start_excerpt.range.start.to_offset(&start_excerpt.buffer) + start_overshoot;
 299
 300            cursor.seek(&end, Bias::Right, &());
 301            if cursor.item().is_none() && end == *cursor.start() {
 302                cursor.prev(&());
 303            }
 304            let end_excerpt = cursor.item().expect("end offset out of bounds");
 305            let end_overshoot = end - cursor.start();
 306            let buffer_end = end_excerpt.range.start.to_offset(&end_excerpt.buffer) + end_overshoot;
 307
 308            if start_excerpt.id == end_excerpt.id {
 309                buffer_edits
 310                    .entry(start_excerpt.buffer_id)
 311                    .or_insert(Vec::new())
 312                    .push((buffer_start..buffer_end, true));
 313            } else {
 314                let start_excerpt_range =
 315                    buffer_start..start_excerpt.range.end.to_offset(&start_excerpt.buffer);
 316                let end_excerpt_range =
 317                    end_excerpt.range.start.to_offset(&end_excerpt.buffer)..buffer_end;
 318                buffer_edits
 319                    .entry(start_excerpt.buffer_id)
 320                    .or_insert(Vec::new())
 321                    .push((start_excerpt_range, true));
 322                buffer_edits
 323                    .entry(end_excerpt.buffer_id)
 324                    .or_insert(Vec::new())
 325                    .push((end_excerpt_range, false));
 326
 327                cursor.seek(&start, Bias::Right, &());
 328                cursor.next(&());
 329                while let Some(excerpt) = cursor.item() {
 330                    if excerpt.id == end_excerpt.id {
 331                        break;
 332                    }
 333                    buffer_edits
 334                        .entry(excerpt.buffer_id)
 335                        .or_insert(Vec::new())
 336                        .push((excerpt.range.to_offset(&excerpt.buffer), false));
 337                    cursor.next(&());
 338                }
 339            }
 340        }
 341
 342        let new_text = new_text.into();
 343        for (buffer_id, mut edits) in buffer_edits {
 344            edits.sort_unstable_by_key(|(range, _)| range.start);
 345            self.buffers.borrow()[&buffer_id]
 346                .buffer
 347                .update(cx, |buffer, cx| {
 348                    let mut edits = edits.into_iter().peekable();
 349                    let mut insertions = Vec::new();
 350                    let mut deletions = Vec::new();
 351                    while let Some((mut range, mut is_insertion)) = edits.next() {
 352                        while let Some((next_range, next_is_insertion)) = edits.peek() {
 353                            if range.end >= next_range.start {
 354                                range.end = cmp::max(next_range.end, range.end);
 355                                is_insertion |= *next_is_insertion;
 356                                edits.next();
 357                            } else {
 358                                break;
 359                            }
 360                        }
 361
 362                        if is_insertion {
 363                            insertions.push(
 364                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 365                            );
 366                        } else if !range.is_empty() {
 367                            deletions.push(
 368                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 369                            );
 370                        }
 371                    }
 372
 373                    if autoindent {
 374                        buffer.edit_with_autoindent(deletions, "", cx);
 375                        buffer.edit_with_autoindent(insertions, new_text.clone(), cx);
 376                    } else {
 377                        buffer.edit(deletions, "", cx);
 378                        buffer.edit(insertions, new_text.clone(), cx);
 379                    }
 380                })
 381        }
 382    }
 383
 384    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 385        self.start_transaction_at(Instant::now(), cx)
 386    }
 387
 388    pub(crate) fn start_transaction_at(
 389        &mut self,
 390        now: Instant,
 391        cx: &mut ModelContext<Self>,
 392    ) -> Option<TransactionId> {
 393        if let Some(buffer) = self.as_singleton() {
 394            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 395        }
 396
 397        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 398            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 399        }
 400        self.history.start_transaction(now)
 401    }
 402
 403    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 404        self.end_transaction_at(Instant::now(), cx)
 405    }
 406
 407    pub(crate) fn end_transaction_at(
 408        &mut self,
 409        now: Instant,
 410        cx: &mut ModelContext<Self>,
 411    ) -> Option<TransactionId> {
 412        if let Some(buffer) = self.as_singleton() {
 413            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 414        }
 415
 416        let mut buffer_transactions = HashSet::default();
 417        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 418            if let Some(transaction_id) =
 419                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 420            {
 421                buffer_transactions.insert((buffer.id(), transaction_id));
 422            }
 423        }
 424
 425        if self.history.end_transaction(now, buffer_transactions) {
 426            let transaction_id = self.history.group().unwrap();
 427            Some(transaction_id)
 428        } else {
 429            None
 430        }
 431    }
 432
 433    pub fn finalize_last_transaction(&mut self, cx: &mut ModelContext<Self>) {
 434        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 435            buffer.update(cx, |buffer, _| {
 436                buffer.finalize_last_transaction();
 437            });
 438        }
 439    }
 440
 441    pub fn set_active_selections(
 442        &mut self,
 443        selections: &[Selection<Anchor>],
 444        cx: &mut ModelContext<Self>,
 445    ) {
 446        let mut selections_by_buffer: HashMap<usize, Vec<Selection<text::Anchor>>> =
 447            Default::default();
 448        let snapshot = self.read(cx);
 449        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 450        for selection in selections {
 451            cursor.seek(&Some(&selection.start.excerpt_id), Bias::Left, &());
 452            while let Some(excerpt) = cursor.item() {
 453                if excerpt.id > selection.end.excerpt_id {
 454                    break;
 455                }
 456
 457                let mut start = excerpt.range.start.clone();
 458                let mut end = excerpt.range.end.clone();
 459                if excerpt.id == selection.start.excerpt_id {
 460                    start = selection.start.text_anchor.clone();
 461                }
 462                if excerpt.id == selection.end.excerpt_id {
 463                    end = selection.end.text_anchor.clone();
 464                }
 465                selections_by_buffer
 466                    .entry(excerpt.buffer_id)
 467                    .or_default()
 468                    .push(Selection {
 469                        id: selection.id,
 470                        start,
 471                        end,
 472                        reversed: selection.reversed,
 473                        goal: selection.goal,
 474                    });
 475
 476                cursor.next(&());
 477            }
 478        }
 479
 480        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 481            if !selections_by_buffer.contains_key(buffer_id) {
 482                buffer_state
 483                    .buffer
 484                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 485            }
 486        }
 487
 488        for (buffer_id, mut selections) in selections_by_buffer {
 489            self.buffers.borrow()[&buffer_id]
 490                .buffer
 491                .update(cx, |buffer, cx| {
 492                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer).unwrap());
 493                    let mut selections = selections.into_iter().peekable();
 494                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 495                        let mut selection = selections.next()?;
 496                        while let Some(next_selection) = selections.peek() {
 497                            if selection
 498                                .end
 499                                .cmp(&next_selection.start, buffer)
 500                                .unwrap()
 501                                .is_ge()
 502                            {
 503                                let next_selection = selections.next().unwrap();
 504                                if next_selection
 505                                    .end
 506                                    .cmp(&selection.end, buffer)
 507                                    .unwrap()
 508                                    .is_ge()
 509                                {
 510                                    selection.end = next_selection.end;
 511                                }
 512                            } else {
 513                                break;
 514                            }
 515                        }
 516                        Some(selection)
 517                    }));
 518                    buffer.set_active_selections(merged_selections, cx);
 519                });
 520        }
 521    }
 522
 523    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
 524        for buffer in self.buffers.borrow().values() {
 525            buffer
 526                .buffer
 527                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 528        }
 529    }
 530
 531    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 532        if let Some(buffer) = self.as_singleton() {
 533            return buffer.update(cx, |buffer, cx| buffer.undo(cx));
 534        }
 535
 536        while let Some(transaction) = self.history.pop_undo() {
 537            let mut undone = false;
 538            for (buffer_id, buffer_transaction_id) in &transaction.buffer_transactions {
 539                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 540                    undone |= buffer.update(cx, |buf, cx| {
 541                        buf.undo_transaction(*buffer_transaction_id, cx)
 542                    });
 543                }
 544            }
 545
 546            if undone {
 547                return Some(transaction.id);
 548            }
 549        }
 550
 551        None
 552    }
 553
 554    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 555        if let Some(buffer) = self.as_singleton() {
 556            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
 557        }
 558
 559        while let Some(transaction) = self.history.pop_redo() {
 560            let mut redone = false;
 561            for (buffer_id, buffer_transaction_id) in &transaction.buffer_transactions {
 562                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 563                    redone |= buffer.update(cx, |buf, cx| {
 564                        buf.redo_transaction(*buffer_transaction_id, cx)
 565                    });
 566                }
 567            }
 568
 569            if redone {
 570                return Some(transaction.id);
 571            }
 572        }
 573
 574        None
 575    }
 576
 577    pub fn push_excerpts<O>(
 578        &mut self,
 579        buffer: ModelHandle<Buffer>,
 580        ranges: impl IntoIterator<Item = Range<O>>,
 581        cx: &mut ModelContext<Self>,
 582    ) -> Vec<ExcerptId>
 583    where
 584        O: text::ToOffset,
 585    {
 586        self.insert_excerpts_after(&ExcerptId::max(), buffer, ranges, cx)
 587    }
 588
 589    pub fn insert_excerpts_after<O>(
 590        &mut self,
 591        prev_excerpt_id: &ExcerptId,
 592        buffer: ModelHandle<Buffer>,
 593        ranges: impl IntoIterator<Item = Range<O>>,
 594        cx: &mut ModelContext<Self>,
 595    ) -> Vec<ExcerptId>
 596    where
 597        O: text::ToOffset,
 598    {
 599        assert_eq!(self.history.transaction_depth, 0);
 600        self.sync(cx);
 601
 602        let buffer_id = buffer.id();
 603        let buffer_snapshot = buffer.read(cx).snapshot();
 604
 605        let mut buffers = self.buffers.borrow_mut();
 606        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
 607            last_version: buffer_snapshot.version().clone(),
 608            last_parse_count: buffer_snapshot.parse_count(),
 609            last_selections_update_count: buffer_snapshot.selections_update_count(),
 610            last_diagnostics_update_count: buffer_snapshot.diagnostics_update_count(),
 611            last_file_update_count: buffer_snapshot.file_update_count(),
 612            excerpts: Default::default(),
 613            _subscriptions: [
 614                cx.observe(&buffer, |_, _, cx| cx.notify()),
 615                cx.subscribe(&buffer, Self::on_buffer_event),
 616            ],
 617            buffer,
 618        });
 619
 620        let mut snapshot = self.snapshot.borrow_mut();
 621        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 622        let mut new_excerpts = cursor.slice(&Some(prev_excerpt_id), Bias::Right, &());
 623
 624        let mut prev_id = ExcerptId::min();
 625        let edit_start = new_excerpts.summary().text.bytes;
 626        new_excerpts.update_last(
 627            |excerpt| {
 628                excerpt.has_trailing_newline = true;
 629                prev_id = excerpt.id.clone();
 630            },
 631            &(),
 632        );
 633
 634        let mut next_id = ExcerptId::max();
 635        if let Some(next_excerpt) = cursor.item() {
 636            next_id = next_excerpt.id.clone();
 637        }
 638
 639        let mut ids = Vec::new();
 640        let mut ranges = ranges.into_iter().peekable();
 641        while let Some(range) = ranges.next() {
 642            let id = ExcerptId::between(&prev_id, &next_id);
 643            if let Err(ix) = buffer_state.excerpts.binary_search(&id) {
 644                buffer_state.excerpts.insert(ix, id.clone());
 645            }
 646            let range = buffer_snapshot.anchor_before(&range.start)
 647                ..buffer_snapshot.anchor_after(&range.end);
 648            let excerpt = Excerpt::new(
 649                id.clone(),
 650                buffer_id,
 651                buffer_snapshot.clone(),
 652                range,
 653                ranges.peek().is_some() || cursor.item().is_some(),
 654            );
 655            new_excerpts.push(excerpt, &());
 656            prev_id = id.clone();
 657            ids.push(id);
 658        }
 659
 660        let edit_end = new_excerpts.summary().text.bytes;
 661
 662        let suffix = cursor.suffix(&());
 663        let changed_trailing_excerpt = suffix.is_empty();
 664        new_excerpts.push_tree(suffix, &());
 665        drop(cursor);
 666        snapshot.excerpts = new_excerpts;
 667        if changed_trailing_excerpt {
 668            snapshot.trailing_excerpt_update_count += 1;
 669        }
 670
 671        self.subscriptions.publish_mut([Edit {
 672            old: edit_start..edit_start,
 673            new: edit_start..edit_end,
 674        }]);
 675
 676        cx.notify();
 677        ids
 678    }
 679
 680    pub fn excerpt_ids_for_buffer(&self, buffer: &ModelHandle<Buffer>) -> Vec<ExcerptId> {
 681        self.buffers
 682            .borrow()
 683            .get(&buffer.id())
 684            .map_or(Vec::new(), |state| state.excerpts.clone())
 685    }
 686
 687    pub fn excerpted_buffers<'a, T: ToOffset>(
 688        &'a self,
 689        range: Range<T>,
 690        cx: &AppContext,
 691    ) -> Vec<(ModelHandle<Buffer>, Range<usize>)> {
 692        let snapshot = self.snapshot(cx);
 693        let start = range.start.to_offset(&snapshot);
 694        let end = range.end.to_offset(&snapshot);
 695
 696        let mut result = Vec::new();
 697        let mut cursor = snapshot.excerpts.cursor::<usize>();
 698        cursor.seek(&start, Bias::Right, &());
 699        while let Some(excerpt) = cursor.item() {
 700            if *cursor.start() > end {
 701                break;
 702            }
 703
 704            let mut end_before_newline = cursor.end(&());
 705            if excerpt.has_trailing_newline {
 706                end_before_newline -= 1;
 707            }
 708            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
 709            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
 710            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
 711            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
 712            result.push((buffer, start..end));
 713            cursor.next(&());
 714        }
 715
 716        result
 717    }
 718
 719    pub fn remove_excerpts<'a>(
 720        &mut self,
 721        excerpt_ids: impl IntoIterator<Item = &'a ExcerptId>,
 722        cx: &mut ModelContext<Self>,
 723    ) {
 724        let mut buffers = self.buffers.borrow_mut();
 725        let mut snapshot = self.snapshot.borrow_mut();
 726        let mut new_excerpts = SumTree::new();
 727        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
 728        let mut edits = Vec::new();
 729        let mut excerpt_ids = excerpt_ids.into_iter().peekable();
 730
 731        while let Some(mut excerpt_id) = excerpt_ids.next() {
 732            // Seek to the next excerpt to remove, preserving any preceding excerpts.
 733            new_excerpts.push_tree(cursor.slice(&Some(excerpt_id), Bias::Left, &()), &());
 734            if let Some(mut excerpt) = cursor.item() {
 735                if excerpt.id != *excerpt_id {
 736                    continue;
 737                }
 738                let mut old_start = cursor.start().1;
 739
 740                // Skip over the removed excerpt.
 741                loop {
 742                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
 743                        buffer_state.excerpts.retain(|id| id != excerpt_id);
 744                        if buffer_state.excerpts.is_empty() {
 745                            buffers.remove(&excerpt.buffer_id);
 746                        }
 747                    }
 748                    cursor.next(&());
 749
 750                    // Skip over any subsequent excerpts that are also removed.
 751                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
 752                        if let Some(next_excerpt) = cursor.item() {
 753                            if next_excerpt.id == *next_excerpt_id {
 754                                excerpt = next_excerpt;
 755                                excerpt_id = excerpt_ids.next().unwrap();
 756                                continue;
 757                            }
 758                        }
 759                    }
 760
 761                    break;
 762                }
 763
 764                // When removing the last excerpt, remove the trailing newline from
 765                // the previous excerpt.
 766                if cursor.item().is_none() && old_start > 0 {
 767                    old_start -= 1;
 768                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
 769                }
 770
 771                // Push an edit for the removal of this run of excerpts.
 772                let old_end = cursor.start().1;
 773                let new_start = new_excerpts.summary().text.bytes;
 774                edits.push(Edit {
 775                    old: old_start..old_end,
 776                    new: new_start..new_start,
 777                });
 778            }
 779        }
 780        let suffix = cursor.suffix(&());
 781        let changed_trailing_excerpt = suffix.is_empty();
 782        new_excerpts.push_tree(suffix, &());
 783        drop(cursor);
 784        snapshot.excerpts = new_excerpts;
 785        if changed_trailing_excerpt {
 786            snapshot.trailing_excerpt_update_count += 1;
 787        }
 788
 789        self.subscriptions.publish_mut(edits);
 790        cx.notify();
 791    }
 792
 793    pub fn text_anchor_for_position<'a, T: ToOffset>(
 794        &'a self,
 795        position: T,
 796        cx: &AppContext,
 797    ) -> (ModelHandle<Buffer>, language::Anchor) {
 798        let snapshot = self.read(cx);
 799        let anchor = snapshot.anchor_before(position);
 800        (
 801            self.buffers.borrow()[&anchor.buffer_id].buffer.clone(),
 802            anchor.text_anchor,
 803        )
 804    }
 805
 806    fn on_buffer_event(
 807        &mut self,
 808        _: ModelHandle<Buffer>,
 809        event: &Event,
 810        cx: &mut ModelContext<Self>,
 811    ) {
 812        cx.emit(event.clone());
 813    }
 814
 815    pub fn format(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
 816        let mut format_tasks = Vec::new();
 817        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 818            format_tasks.push(buffer.update(cx, |buffer, cx| buffer.format(cx)));
 819        }
 820
 821        cx.spawn(|_, _| async move {
 822            for format in format_tasks {
 823                format.await?;
 824            }
 825            Ok(())
 826        })
 827    }
 828
 829    pub fn save(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
 830        let mut save_tasks = Vec::new();
 831        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 832            save_tasks.push(buffer.update(cx, |buffer, cx| buffer.save(cx)));
 833        }
 834
 835        cx.spawn(|_, _| async move {
 836            for save in save_tasks {
 837                save.await?;
 838            }
 839            Ok(())
 840        })
 841    }
 842
 843    pub fn is_completion_trigger<T>(&self, position: T, text: &str, cx: &AppContext) -> bool
 844    where
 845        T: ToOffset,
 846    {
 847        let mut chars = text.chars();
 848        let char = if let Some(char) = chars.next() {
 849            char
 850        } else {
 851            return false;
 852        };
 853        if chars.next().is_some() {
 854            return false;
 855        }
 856
 857        if char.is_alphanumeric() || char == '_' {
 858            return true;
 859        }
 860
 861        let snapshot = self.snapshot(cx);
 862        let anchor = snapshot.anchor_before(position);
 863        let buffer = self.buffers.borrow()[&anchor.buffer_id].buffer.clone();
 864        buffer
 865            .read(cx)
 866            .completion_triggers()
 867            .iter()
 868            .any(|string| string == text)
 869    }
 870
 871    pub fn language<'a>(&self, cx: &'a AppContext) -> Option<&'a Arc<Language>> {
 872        self.buffers
 873            .borrow()
 874            .values()
 875            .next()
 876            .and_then(|state| state.buffer.read(cx).language())
 877    }
 878
 879    pub fn file<'a>(&self, cx: &'a AppContext) -> Option<&'a dyn File> {
 880        self.as_singleton()?.read(cx).file()
 881    }
 882
 883    #[cfg(test)]
 884    pub fn is_parsing(&self, cx: &AppContext) -> bool {
 885        self.as_singleton().unwrap().read(cx).is_parsing()
 886    }
 887
 888    fn sync(&self, cx: &AppContext) {
 889        let mut snapshot = self.snapshot.borrow_mut();
 890        let mut excerpts_to_edit = Vec::new();
 891        let mut reparsed = false;
 892        let mut diagnostics_updated = false;
 893        let mut is_dirty = false;
 894        let mut has_conflict = false;
 895        let mut buffers = self.buffers.borrow_mut();
 896        for buffer_state in buffers.values_mut() {
 897            let buffer = buffer_state.buffer.read(cx);
 898            let version = buffer.version();
 899            let parse_count = buffer.parse_count();
 900            let selections_update_count = buffer.selections_update_count();
 901            let diagnostics_update_count = buffer.diagnostics_update_count();
 902            let file_update_count = buffer.file_update_count();
 903
 904            let buffer_edited = version.changed_since(&buffer_state.last_version);
 905            let buffer_reparsed = parse_count > buffer_state.last_parse_count;
 906            let buffer_selections_updated =
 907                selections_update_count > buffer_state.last_selections_update_count;
 908            let buffer_diagnostics_updated =
 909                diagnostics_update_count > buffer_state.last_diagnostics_update_count;
 910            let buffer_file_updated = file_update_count > buffer_state.last_file_update_count;
 911            if buffer_edited
 912                || buffer_reparsed
 913                || buffer_selections_updated
 914                || buffer_diagnostics_updated
 915                || buffer_file_updated
 916            {
 917                buffer_state.last_version = version;
 918                buffer_state.last_parse_count = parse_count;
 919                buffer_state.last_selections_update_count = selections_update_count;
 920                buffer_state.last_diagnostics_update_count = diagnostics_update_count;
 921                buffer_state.last_file_update_count = file_update_count;
 922                excerpts_to_edit.extend(
 923                    buffer_state
 924                        .excerpts
 925                        .iter()
 926                        .map(|excerpt_id| (excerpt_id, buffer_state.buffer.clone(), buffer_edited)),
 927                );
 928            }
 929
 930            reparsed |= buffer_reparsed;
 931            diagnostics_updated |= buffer_diagnostics_updated;
 932            is_dirty |= buffer.is_dirty();
 933            has_conflict |= buffer.has_conflict();
 934        }
 935        if reparsed {
 936            snapshot.parse_count += 1;
 937        }
 938        if diagnostics_updated {
 939            snapshot.diagnostics_update_count += 1;
 940        }
 941        snapshot.is_dirty = is_dirty;
 942        snapshot.has_conflict = has_conflict;
 943
 944        excerpts_to_edit.sort_unstable_by_key(|(excerpt_id, _, _)| *excerpt_id);
 945
 946        let mut edits = Vec::new();
 947        let mut new_excerpts = SumTree::new();
 948        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
 949
 950        for (id, buffer, buffer_edited) in excerpts_to_edit {
 951            new_excerpts.push_tree(cursor.slice(&Some(id), Bias::Left, &()), &());
 952            let old_excerpt = cursor.item().unwrap();
 953            let buffer_id = buffer.id();
 954            let buffer = buffer.read(cx);
 955
 956            let mut new_excerpt;
 957            if buffer_edited {
 958                edits.extend(
 959                    buffer
 960                        .edits_since_in_range::<usize>(
 961                            old_excerpt.buffer.version(),
 962                            old_excerpt.range.clone(),
 963                        )
 964                        .map(|mut edit| {
 965                            let excerpt_old_start = cursor.start().1;
 966                            let excerpt_new_start = new_excerpts.summary().text.bytes;
 967                            edit.old.start += excerpt_old_start;
 968                            edit.old.end += excerpt_old_start;
 969                            edit.new.start += excerpt_new_start;
 970                            edit.new.end += excerpt_new_start;
 971                            edit
 972                        }),
 973                );
 974
 975                new_excerpt = Excerpt::new(
 976                    id.clone(),
 977                    buffer_id,
 978                    buffer.snapshot(),
 979                    old_excerpt.range.clone(),
 980                    old_excerpt.has_trailing_newline,
 981                );
 982            } else {
 983                new_excerpt = old_excerpt.clone();
 984                new_excerpt.buffer = buffer.snapshot();
 985            }
 986
 987            new_excerpts.push(new_excerpt, &());
 988            cursor.next(&());
 989        }
 990        new_excerpts.push_tree(cursor.suffix(&()), &());
 991
 992        drop(cursor);
 993        snapshot.excerpts = new_excerpts;
 994
 995        self.subscriptions.publish(edits);
 996    }
 997}
 998
 999#[cfg(any(test, feature = "test-support"))]
1000impl MultiBuffer {
1001    pub fn randomly_edit(
1002        &mut self,
1003        rng: &mut impl rand::Rng,
1004        count: usize,
1005        cx: &mut ModelContext<Self>,
1006    ) {
1007        use text::RandomCharIter;
1008
1009        let snapshot = self.read(cx);
1010        let mut old_ranges: Vec<Range<usize>> = Vec::new();
1011        for _ in 0..count {
1012            let last_end = old_ranges.last().map_or(0, |last_range| last_range.end + 1);
1013            if last_end > snapshot.len() {
1014                break;
1015            }
1016            let end_ix = snapshot.clip_offset(rng.gen_range(0..=last_end), Bias::Right);
1017            let start_ix = snapshot.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1018            old_ranges.push(start_ix..end_ix);
1019        }
1020        let new_text_len = rng.gen_range(0..10);
1021        let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1022        log::info!("mutating multi-buffer at {:?}: {:?}", old_ranges, new_text);
1023        drop(snapshot);
1024
1025        self.edit(old_ranges.iter().cloned(), new_text.as_str(), cx);
1026    }
1027
1028    pub fn randomly_edit_excerpts(
1029        &mut self,
1030        rng: &mut impl rand::Rng,
1031        mutation_count: usize,
1032        cx: &mut ModelContext<Self>,
1033    ) {
1034        use rand::prelude::*;
1035        use std::env;
1036        use text::RandomCharIter;
1037
1038        let max_excerpts = env::var("MAX_EXCERPTS")
1039            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
1040            .unwrap_or(5);
1041
1042        let mut buffers = Vec::new();
1043        for _ in 0..mutation_count {
1044            let excerpt_ids = self
1045                .buffers
1046                .borrow()
1047                .values()
1048                .flat_map(|b| &b.excerpts)
1049                .cloned()
1050                .collect::<Vec<_>>();
1051            if excerpt_ids.len() == 0 || (rng.gen() && excerpt_ids.len() < max_excerpts) {
1052                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
1053                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
1054                    buffers.push(cx.add_model(|cx| Buffer::new(0, text, cx)));
1055                    let buffer = buffers.last().unwrap();
1056                    log::info!(
1057                        "Creating new buffer {} with text: {:?}",
1058                        buffer.id(),
1059                        buffer.read(cx).text()
1060                    );
1061                    buffers.last().unwrap().clone()
1062                } else {
1063                    self.buffers
1064                        .borrow()
1065                        .values()
1066                        .choose(rng)
1067                        .unwrap()
1068                        .buffer
1069                        .clone()
1070                };
1071
1072                let buffer = buffer_handle.read(cx);
1073                let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
1074                let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1075                log::info!(
1076                    "Inserting excerpt from buffer {} and range {:?}: {:?}",
1077                    buffer_handle.id(),
1078                    start_ix..end_ix,
1079                    &buffer.text()[start_ix..end_ix]
1080                );
1081
1082                let excerpt_id = self.push_excerpts(buffer_handle.clone(), [start_ix..end_ix], cx);
1083                log::info!("Inserted with id: {:?}", excerpt_id);
1084            } else {
1085                let remove_count = rng.gen_range(1..=excerpt_ids.len());
1086                let mut excerpts_to_remove = excerpt_ids
1087                    .choose_multiple(rng, remove_count)
1088                    .cloned()
1089                    .collect::<Vec<_>>();
1090                excerpts_to_remove.sort();
1091                log::info!("Removing excerpts {:?}", excerpts_to_remove);
1092                self.remove_excerpts(&excerpts_to_remove, cx);
1093            }
1094        }
1095    }
1096
1097    pub fn randomly_mutate(
1098        &mut self,
1099        rng: &mut impl rand::Rng,
1100        mutation_count: usize,
1101        cx: &mut ModelContext<Self>,
1102    ) {
1103        if rng.gen_bool(0.7) || self.singleton {
1104            self.randomly_edit(rng, mutation_count, cx);
1105        } else {
1106            self.randomly_edit_excerpts(rng, mutation_count, cx);
1107        }
1108    }
1109}
1110
1111impl Entity for MultiBuffer {
1112    type Event = language::Event;
1113}
1114
1115impl MultiBufferSnapshot {
1116    pub fn text(&self) -> String {
1117        self.chunks(0..self.len(), false)
1118            .map(|chunk| chunk.text)
1119            .collect()
1120    }
1121
1122    pub fn reversed_chars_at<'a, T: ToOffset>(
1123        &'a self,
1124        position: T,
1125    ) -> impl Iterator<Item = char> + 'a {
1126        let mut offset = position.to_offset(self);
1127        let mut cursor = self.excerpts.cursor::<usize>();
1128        cursor.seek(&offset, Bias::Left, &());
1129        let mut excerpt_chunks = cursor.item().map(|excerpt| {
1130            let end_before_footer = cursor.start() + excerpt.text_summary.bytes;
1131            let start = excerpt.range.start.to_offset(&excerpt.buffer);
1132            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
1133            excerpt.buffer.reversed_chunks_in_range(start..end)
1134        });
1135        iter::from_fn(move || {
1136            if offset == *cursor.start() {
1137                cursor.prev(&());
1138                let excerpt = cursor.item()?;
1139                excerpt_chunks = Some(
1140                    excerpt
1141                        .buffer
1142                        .reversed_chunks_in_range(excerpt.range.clone()),
1143                );
1144            }
1145
1146            let excerpt = cursor.item().unwrap();
1147            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
1148                offset -= 1;
1149                Some("\n")
1150            } else {
1151                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
1152                offset -= chunk.len();
1153                Some(chunk)
1154            }
1155        })
1156        .flat_map(|c| c.chars().rev())
1157    }
1158
1159    pub fn chars_at<'a, T: ToOffset>(&'a self, position: T) -> impl Iterator<Item = char> + 'a {
1160        let offset = position.to_offset(self);
1161        self.text_for_range(offset..self.len())
1162            .flat_map(|chunk| chunk.chars())
1163    }
1164
1165    pub fn text_for_range<'a, T: ToOffset>(
1166        &'a self,
1167        range: Range<T>,
1168    ) -> impl Iterator<Item = &'a str> {
1169        self.chunks(range, false).map(|chunk| chunk.text)
1170    }
1171
1172    pub fn is_line_blank(&self, row: u32) -> bool {
1173        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1174            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1175    }
1176
1177    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1178    where
1179        T: ToOffset,
1180    {
1181        let position = position.to_offset(self);
1182        position == self.clip_offset(position, Bias::Left)
1183            && self
1184                .bytes_in_range(position..self.len())
1185                .flatten()
1186                .copied()
1187                .take(needle.len())
1188                .eq(needle.bytes())
1189    }
1190
1191    pub fn surrounding_word<T: ToOffset>(&self, start: T) -> (Range<usize>, Option<CharKind>) {
1192        let mut start = start.to_offset(self);
1193        let mut end = start;
1194        let mut next_chars = self.chars_at(start).peekable();
1195        let mut prev_chars = self.reversed_chars_at(start).peekable();
1196        let word_kind = cmp::max(
1197            prev_chars.peek().copied().map(char_kind),
1198            next_chars.peek().copied().map(char_kind),
1199        );
1200
1201        for ch in prev_chars {
1202            if Some(char_kind(ch)) == word_kind {
1203                start -= ch.len_utf8();
1204            } else {
1205                break;
1206            }
1207        }
1208
1209        for ch in next_chars {
1210            if Some(char_kind(ch)) == word_kind {
1211                end += ch.len_utf8();
1212            } else {
1213                break;
1214            }
1215        }
1216
1217        (start..end, word_kind)
1218    }
1219
1220    fn as_singleton(&self) -> Option<&Excerpt> {
1221        if self.singleton {
1222            self.excerpts.iter().next()
1223        } else {
1224            None
1225        }
1226    }
1227
1228    pub fn len(&self) -> usize {
1229        self.excerpts.summary().text.bytes
1230    }
1231
1232    pub fn max_buffer_row(&self) -> u32 {
1233        self.excerpts.summary().max_buffer_row
1234    }
1235
1236    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
1237        if let Some(excerpt) = self.as_singleton() {
1238            return excerpt.buffer.clip_offset(offset, bias);
1239        }
1240
1241        let mut cursor = self.excerpts.cursor::<usize>();
1242        cursor.seek(&offset, Bias::Right, &());
1243        let overshoot = if let Some(excerpt) = cursor.item() {
1244            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1245            let buffer_offset = excerpt
1246                .buffer
1247                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
1248            buffer_offset.saturating_sub(excerpt_start)
1249        } else {
1250            0
1251        };
1252        cursor.start() + overshoot
1253    }
1254
1255    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1256        if let Some(excerpt) = self.as_singleton() {
1257            return excerpt.buffer.clip_point(point, bias);
1258        }
1259
1260        let mut cursor = self.excerpts.cursor::<Point>();
1261        cursor.seek(&point, Bias::Right, &());
1262        let overshoot = if let Some(excerpt) = cursor.item() {
1263            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1264            let buffer_point = excerpt
1265                .buffer
1266                .clip_point(excerpt_start + (point - cursor.start()), bias);
1267            buffer_point.saturating_sub(excerpt_start)
1268        } else {
1269            Point::zero()
1270        };
1271        *cursor.start() + overshoot
1272    }
1273
1274    pub fn clip_point_utf16(&self, point: PointUtf16, bias: Bias) -> PointUtf16 {
1275        if let Some(excerpt) = self.as_singleton() {
1276            return excerpt.buffer.clip_point_utf16(point, bias);
1277        }
1278
1279        let mut cursor = self.excerpts.cursor::<PointUtf16>();
1280        cursor.seek(&point, Bias::Right, &());
1281        let overshoot = if let Some(excerpt) = cursor.item() {
1282            let excerpt_start = excerpt
1283                .buffer
1284                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1285            let buffer_point = excerpt
1286                .buffer
1287                .clip_point_utf16(excerpt_start + (point - cursor.start()), bias);
1288            buffer_point.saturating_sub(excerpt_start)
1289        } else {
1290            PointUtf16::zero()
1291        };
1292        *cursor.start() + overshoot
1293    }
1294
1295    pub fn bytes_in_range<'a, T: ToOffset>(&'a self, range: Range<T>) -> MultiBufferBytes<'a> {
1296        let range = range.start.to_offset(self)..range.end.to_offset(self);
1297        let mut excerpts = self.excerpts.cursor::<usize>();
1298        excerpts.seek(&range.start, Bias::Right, &());
1299
1300        let mut chunk = &[][..];
1301        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
1302            let mut excerpt_bytes = excerpt
1303                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
1304            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
1305            Some(excerpt_bytes)
1306        } else {
1307            None
1308        };
1309
1310        MultiBufferBytes {
1311            range,
1312            excerpts,
1313            excerpt_bytes,
1314            chunk,
1315        }
1316    }
1317
1318    pub fn buffer_rows<'a>(&'a self, start_row: u32) -> MultiBufferRows<'a> {
1319        let mut result = MultiBufferRows {
1320            buffer_row_range: 0..0,
1321            excerpts: self.excerpts.cursor(),
1322        };
1323        result.seek(start_row);
1324        result
1325    }
1326
1327    pub fn chunks<'a, T: ToOffset>(
1328        &'a self,
1329        range: Range<T>,
1330        language_aware: bool,
1331    ) -> MultiBufferChunks<'a> {
1332        let range = range.start.to_offset(self)..range.end.to_offset(self);
1333        let mut chunks = MultiBufferChunks {
1334            range: range.clone(),
1335            excerpts: self.excerpts.cursor(),
1336            excerpt_chunks: None,
1337            language_aware,
1338        };
1339        chunks.seek(range.start);
1340        chunks
1341    }
1342
1343    pub fn offset_to_point(&self, offset: usize) -> Point {
1344        if let Some(excerpt) = self.as_singleton() {
1345            return excerpt.buffer.offset_to_point(offset);
1346        }
1347
1348        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1349        cursor.seek(&offset, Bias::Right, &());
1350        if let Some(excerpt) = cursor.item() {
1351            let (start_offset, start_point) = cursor.start();
1352            let overshoot = offset - start_offset;
1353            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1354            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1355            let buffer_point = excerpt
1356                .buffer
1357                .offset_to_point(excerpt_start_offset + overshoot);
1358            *start_point + (buffer_point - excerpt_start_point)
1359        } else {
1360            self.excerpts.summary().text.lines
1361        }
1362    }
1363
1364    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
1365        if let Some(excerpt) = self.as_singleton() {
1366            return excerpt.buffer.offset_to_point_utf16(offset);
1367        }
1368
1369        let mut cursor = self.excerpts.cursor::<(usize, PointUtf16)>();
1370        cursor.seek(&offset, Bias::Right, &());
1371        if let Some(excerpt) = cursor.item() {
1372            let (start_offset, start_point) = cursor.start();
1373            let overshoot = offset - start_offset;
1374            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1375            let excerpt_start_point = excerpt.range.start.to_point_utf16(&excerpt.buffer);
1376            let buffer_point = excerpt
1377                .buffer
1378                .offset_to_point_utf16(excerpt_start_offset + overshoot);
1379            *start_point + (buffer_point - excerpt_start_point)
1380        } else {
1381            self.excerpts.summary().text.lines_utf16
1382        }
1383    }
1384
1385    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
1386        if let Some(excerpt) = self.as_singleton() {
1387            return excerpt.buffer.point_to_point_utf16(point);
1388        }
1389
1390        let mut cursor = self.excerpts.cursor::<(Point, PointUtf16)>();
1391        cursor.seek(&point, Bias::Right, &());
1392        if let Some(excerpt) = cursor.item() {
1393            let (start_offset, start_point) = cursor.start();
1394            let overshoot = point - start_offset;
1395            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1396            let excerpt_start_point_utf16 = excerpt.range.start.to_point_utf16(&excerpt.buffer);
1397            let buffer_point = excerpt
1398                .buffer
1399                .point_to_point_utf16(excerpt_start_point + overshoot);
1400            *start_point + (buffer_point - excerpt_start_point_utf16)
1401        } else {
1402            self.excerpts.summary().text.lines_utf16
1403        }
1404    }
1405
1406    pub fn point_to_offset(&self, point: Point) -> usize {
1407        if let Some(excerpt) = self.as_singleton() {
1408            return excerpt.buffer.point_to_offset(point);
1409        }
1410
1411        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
1412        cursor.seek(&point, Bias::Right, &());
1413        if let Some(excerpt) = cursor.item() {
1414            let (start_point, start_offset) = cursor.start();
1415            let overshoot = point - start_point;
1416            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1417            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1418            let buffer_offset = excerpt
1419                .buffer
1420                .point_to_offset(excerpt_start_point + overshoot);
1421            *start_offset + buffer_offset - excerpt_start_offset
1422        } else {
1423            self.excerpts.summary().text.bytes
1424        }
1425    }
1426
1427    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
1428        if let Some(excerpt) = self.as_singleton() {
1429            return excerpt.buffer.point_utf16_to_offset(point);
1430        }
1431
1432        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
1433        cursor.seek(&point, Bias::Right, &());
1434        if let Some(excerpt) = cursor.item() {
1435            let (start_point, start_offset) = cursor.start();
1436            let overshoot = point - start_point;
1437            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1438            let excerpt_start_point = excerpt
1439                .buffer
1440                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1441            let buffer_offset = excerpt
1442                .buffer
1443                .point_utf16_to_offset(excerpt_start_point + overshoot);
1444            *start_offset + (buffer_offset - excerpt_start_offset)
1445        } else {
1446            self.excerpts.summary().text.bytes
1447        }
1448    }
1449
1450    pub fn indent_column_for_line(&self, row: u32) -> u32 {
1451        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
1452            buffer
1453                .indent_column_for_line(range.start.row)
1454                .min(range.end.column)
1455                .saturating_sub(range.start.column)
1456        } else {
1457            0
1458        }
1459    }
1460
1461    pub fn line_len(&self, row: u32) -> u32 {
1462        if let Some((_, range)) = self.buffer_line_for_row(row) {
1463            range.end.column - range.start.column
1464        } else {
1465            0
1466        }
1467    }
1468
1469    fn buffer_line_for_row(&self, row: u32) -> Option<(&BufferSnapshot, Range<Point>)> {
1470        let mut cursor = self.excerpts.cursor::<Point>();
1471        cursor.seek(&Point::new(row, 0), Bias::Right, &());
1472        if let Some(excerpt) = cursor.item() {
1473            let overshoot = row - cursor.start().row;
1474            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1475            let excerpt_end = excerpt.range.end.to_point(&excerpt.buffer);
1476            let buffer_row = excerpt_start.row + overshoot;
1477            let line_start = Point::new(buffer_row, 0);
1478            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
1479            return Some((
1480                &excerpt.buffer,
1481                line_start.max(excerpt_start)..line_end.min(excerpt_end),
1482            ));
1483        }
1484        None
1485    }
1486
1487    pub fn max_point(&self) -> Point {
1488        self.text_summary().lines
1489    }
1490
1491    pub fn text_summary(&self) -> TextSummary {
1492        self.excerpts.summary().text
1493    }
1494
1495    pub fn text_summary_for_range<'a, D, O>(&'a self, range: Range<O>) -> D
1496    where
1497        D: TextDimension,
1498        O: ToOffset,
1499    {
1500        let mut summary = D::default();
1501        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
1502        let mut cursor = self.excerpts.cursor::<usize>();
1503        cursor.seek(&range.start, Bias::Right, &());
1504        if let Some(excerpt) = cursor.item() {
1505            let mut end_before_newline = cursor.end(&());
1506            if excerpt.has_trailing_newline {
1507                end_before_newline -= 1;
1508            }
1509
1510            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1511            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
1512            let end_in_excerpt =
1513                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
1514            summary.add_assign(
1515                &excerpt
1516                    .buffer
1517                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
1518            );
1519
1520            if range.end > end_before_newline {
1521                summary.add_assign(&D::from_text_summary(&TextSummary {
1522                    bytes: 1,
1523                    lines: Point::new(1 as u32, 0),
1524                    lines_utf16: PointUtf16::new(1 as u32, 0),
1525                    first_line_chars: 0,
1526                    last_line_chars: 0,
1527                    longest_row: 0,
1528                    longest_row_chars: 0,
1529                }));
1530            }
1531
1532            cursor.next(&());
1533        }
1534
1535        if range.end > *cursor.start() {
1536            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
1537                &range.end,
1538                Bias::Right,
1539                &(),
1540            )));
1541            if let Some(excerpt) = cursor.item() {
1542                range.end = cmp::max(*cursor.start(), range.end);
1543
1544                let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1545                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
1546                summary.add_assign(
1547                    &excerpt
1548                        .buffer
1549                        .text_summary_for_range(excerpt_start..end_in_excerpt),
1550                );
1551            }
1552        }
1553
1554        summary
1555    }
1556
1557    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
1558    where
1559        D: TextDimension + Ord + Sub<D, Output = D>,
1560    {
1561        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1562        cursor.seek(&Some(&anchor.excerpt_id), Bias::Left, &());
1563        if cursor.item().is_none() {
1564            cursor.next(&());
1565        }
1566
1567        let mut position = D::from_text_summary(&cursor.start().text);
1568        if let Some(excerpt) = cursor.item() {
1569            if excerpt.id == anchor.excerpt_id && excerpt.buffer_id == anchor.buffer_id {
1570                let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1571                let excerpt_buffer_end = excerpt.range.end.summary::<D>(&excerpt.buffer);
1572                let buffer_position = cmp::min(
1573                    excerpt_buffer_end,
1574                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
1575                );
1576                if buffer_position > excerpt_buffer_start {
1577                    position.add_assign(&(buffer_position - excerpt_buffer_start));
1578                }
1579            }
1580        }
1581        position
1582    }
1583
1584    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
1585    where
1586        D: TextDimension + Ord + Sub<D, Output = D>,
1587        I: 'a + IntoIterator<Item = &'a Anchor>,
1588    {
1589        if let Some(excerpt) = self.as_singleton() {
1590            return excerpt
1591                .buffer
1592                .summaries_for_anchors(anchors.into_iter().map(|a| &a.text_anchor))
1593                .collect();
1594        }
1595
1596        let mut anchors = anchors.into_iter().peekable();
1597        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1598        let mut summaries = Vec::new();
1599        while let Some(anchor) = anchors.peek() {
1600            let excerpt_id = &anchor.excerpt_id;
1601            let buffer_id = anchor.buffer_id;
1602            let excerpt_anchors = iter::from_fn(|| {
1603                let anchor = anchors.peek()?;
1604                if anchor.excerpt_id == *excerpt_id && anchor.buffer_id == buffer_id {
1605                    Some(&anchors.next().unwrap().text_anchor)
1606                } else {
1607                    None
1608                }
1609            });
1610
1611            cursor.seek_forward(&Some(excerpt_id), Bias::Left, &());
1612            if cursor.item().is_none() {
1613                cursor.next(&());
1614            }
1615
1616            let position = D::from_text_summary(&cursor.start().text);
1617            if let Some(excerpt) = cursor.item() {
1618                if excerpt.id == *excerpt_id && excerpt.buffer_id == buffer_id {
1619                    let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1620                    let excerpt_buffer_end = excerpt.range.end.summary::<D>(&excerpt.buffer);
1621                    summaries.extend(
1622                        excerpt
1623                            .buffer
1624                            .summaries_for_anchors::<D, _>(excerpt_anchors)
1625                            .map(move |summary| {
1626                                let summary = cmp::min(excerpt_buffer_end.clone(), summary);
1627                                let mut position = position.clone();
1628                                let excerpt_buffer_start = excerpt_buffer_start.clone();
1629                                if summary > excerpt_buffer_start {
1630                                    position.add_assign(&(summary - excerpt_buffer_start));
1631                                }
1632                                position
1633                            }),
1634                    );
1635                    continue;
1636                }
1637            }
1638
1639            summaries.extend(excerpt_anchors.map(|_| position.clone()));
1640        }
1641
1642        summaries
1643    }
1644
1645    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
1646    where
1647        I: 'a + IntoIterator<Item = &'a Anchor>,
1648    {
1649        let mut anchors = anchors.into_iter().enumerate().peekable();
1650        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1651        let mut result = Vec::new();
1652        while let Some((_, anchor)) = anchors.peek() {
1653            let old_excerpt_id = &anchor.excerpt_id;
1654
1655            // Find the location where this anchor's excerpt should be.
1656            cursor.seek_forward(&Some(old_excerpt_id), Bias::Left, &());
1657            if cursor.item().is_none() {
1658                cursor.next(&());
1659            }
1660
1661            let next_excerpt = cursor.item();
1662            let prev_excerpt = cursor.prev_item();
1663
1664            // Process all of the anchors for this excerpt.
1665            while let Some((_, anchor)) = anchors.peek() {
1666                if anchor.excerpt_id != *old_excerpt_id {
1667                    break;
1668                }
1669                let mut kept_position = false;
1670                let (anchor_ix, anchor) = anchors.next().unwrap();
1671                let mut anchor = anchor.clone();
1672
1673                // Leave min and max anchors unchanged.
1674                if *old_excerpt_id == ExcerptId::max() || *old_excerpt_id == ExcerptId::min() {
1675                    kept_position = true;
1676                }
1677                // If the old excerpt still exists at this location, then leave
1678                // the anchor unchanged.
1679                else if next_excerpt.map_or(false, |excerpt| {
1680                    excerpt.id == *old_excerpt_id && excerpt.contains(&anchor)
1681                }) {
1682                    kept_position = true;
1683                }
1684                // If the old excerpt no longer exists at this location, then attempt to
1685                // find an equivalent position for this anchor in an adjacent excerpt.
1686                else {
1687                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
1688                        if excerpt.contains(&anchor) {
1689                            anchor.excerpt_id = excerpt.id.clone();
1690                            kept_position = true;
1691                            break;
1692                        }
1693                    }
1694                }
1695                // If there's no adjacent excerpt that contains the anchor's position,
1696                // then report that the anchor has lost its position.
1697                if !kept_position {
1698                    anchor = if let Some(excerpt) = next_excerpt {
1699                        let mut text_anchor = excerpt
1700                            .range
1701                            .start
1702                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
1703                        if text_anchor
1704                            .cmp(&excerpt.range.end, &excerpt.buffer)
1705                            .unwrap()
1706                            .is_gt()
1707                        {
1708                            text_anchor = excerpt.range.end.clone();
1709                        }
1710                        Anchor {
1711                            buffer_id: excerpt.buffer_id,
1712                            excerpt_id: excerpt.id.clone(),
1713                            text_anchor,
1714                        }
1715                    } else if let Some(excerpt) = prev_excerpt {
1716                        let mut text_anchor = excerpt
1717                            .range
1718                            .end
1719                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
1720                        if text_anchor
1721                            .cmp(&excerpt.range.start, &excerpt.buffer)
1722                            .unwrap()
1723                            .is_lt()
1724                        {
1725                            text_anchor = excerpt.range.start.clone();
1726                        }
1727                        Anchor {
1728                            buffer_id: excerpt.buffer_id,
1729                            excerpt_id: excerpt.id.clone(),
1730                            text_anchor,
1731                        }
1732                    } else if anchor.text_anchor.bias == Bias::Left {
1733                        Anchor::min()
1734                    } else {
1735                        Anchor::max()
1736                    };
1737                }
1738
1739                result.push((anchor_ix, anchor, kept_position));
1740            }
1741        }
1742        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self).unwrap());
1743        result
1744    }
1745
1746    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
1747        self.anchor_at(position, Bias::Left)
1748    }
1749
1750    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
1751        self.anchor_at(position, Bias::Right)
1752    }
1753
1754    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
1755        let offset = position.to_offset(self);
1756        if let Some(excerpt) = self.as_singleton() {
1757            return Anchor {
1758                buffer_id: excerpt.buffer_id,
1759                excerpt_id: excerpt.id.clone(),
1760                text_anchor: excerpt.buffer.anchor_at(offset, bias),
1761            };
1762        }
1763
1764        let mut cursor = self.excerpts.cursor::<(usize, Option<&ExcerptId>)>();
1765        cursor.seek(&offset, Bias::Right, &());
1766        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
1767            cursor.prev(&());
1768        }
1769        if let Some(excerpt) = cursor.item() {
1770            let mut overshoot = offset.saturating_sub(cursor.start().0);
1771            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
1772                overshoot -= 1;
1773                bias = Bias::Right;
1774            }
1775
1776            let buffer_start = excerpt.range.start.to_offset(&excerpt.buffer);
1777            let text_anchor =
1778                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
1779            Anchor {
1780                buffer_id: excerpt.buffer_id,
1781                excerpt_id: excerpt.id.clone(),
1782                text_anchor,
1783            }
1784        } else if offset == 0 && bias == Bias::Left {
1785            Anchor::min()
1786        } else {
1787            Anchor::max()
1788        }
1789    }
1790
1791    pub fn anchor_in_excerpt(&self, excerpt_id: ExcerptId, text_anchor: text::Anchor) -> Anchor {
1792        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1793        cursor.seek(&Some(&excerpt_id), Bias::Left, &());
1794        if let Some(excerpt) = cursor.item() {
1795            if excerpt.id == excerpt_id {
1796                let text_anchor = excerpt.clip_anchor(text_anchor);
1797                drop(cursor);
1798                return Anchor {
1799                    buffer_id: excerpt.buffer_id,
1800                    excerpt_id,
1801                    text_anchor,
1802                };
1803            }
1804        }
1805        panic!("excerpt not found");
1806    }
1807
1808    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
1809        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
1810            true
1811        } else if let Some((buffer_id, buffer_snapshot)) =
1812            self.buffer_snapshot_for_excerpt(&anchor.excerpt_id)
1813        {
1814            anchor.buffer_id == buffer_id && buffer_snapshot.can_resolve(&anchor.text_anchor)
1815        } else {
1816            false
1817        }
1818    }
1819
1820    pub fn excerpt_boundaries_in_range<'a, R, T>(
1821        &'a self,
1822        range: R,
1823    ) -> impl Iterator<Item = ExcerptBoundary> + 'a
1824    where
1825        R: RangeBounds<T>,
1826        T: ToOffset,
1827    {
1828        let start_offset;
1829        let start = match range.start_bound() {
1830            Bound::Included(start) => {
1831                start_offset = start.to_offset(self);
1832                Bound::Included(start_offset)
1833            }
1834            Bound::Excluded(start) => {
1835                start_offset = start.to_offset(self);
1836                Bound::Excluded(start_offset)
1837            }
1838            Bound::Unbounded => {
1839                start_offset = 0;
1840                Bound::Unbounded
1841            }
1842        };
1843        let end = match range.end_bound() {
1844            Bound::Included(end) => Bound::Included(end.to_offset(self)),
1845            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
1846            Bound::Unbounded => Bound::Unbounded,
1847        };
1848        let bounds = (start, end);
1849
1850        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1851        cursor.seek(&start_offset, Bias::Right, &());
1852        if cursor.item().is_none() {
1853            cursor.prev(&());
1854        }
1855        if !bounds.contains(&cursor.start().0) {
1856            cursor.next(&());
1857        }
1858
1859        let mut prev_buffer_id = cursor.prev_item().map(|excerpt| excerpt.buffer_id);
1860        std::iter::from_fn(move || {
1861            if self.singleton {
1862                None
1863            } else if bounds.contains(&cursor.start().0) {
1864                let excerpt = cursor.item()?;
1865                let starts_new_buffer = Some(excerpt.buffer_id) != prev_buffer_id;
1866                let boundary = ExcerptBoundary {
1867                    row: cursor.start().1.row,
1868                    buffer: excerpt.buffer.clone(),
1869                    range: excerpt.range.clone(),
1870                    starts_new_buffer,
1871                };
1872
1873                prev_buffer_id = Some(excerpt.buffer_id);
1874                cursor.next(&());
1875                Some(boundary)
1876            } else {
1877                None
1878            }
1879        })
1880    }
1881
1882    pub fn parse_count(&self) -> usize {
1883        self.parse_count
1884    }
1885
1886    pub fn enclosing_bracket_ranges<T: ToOffset>(
1887        &self,
1888        range: Range<T>,
1889    ) -> Option<(Range<usize>, Range<usize>)> {
1890        let range = range.start.to_offset(self)..range.end.to_offset(self);
1891
1892        let mut cursor = self.excerpts.cursor::<usize>();
1893        cursor.seek(&range.start, Bias::Right, &());
1894        let start_excerpt = cursor.item();
1895
1896        cursor.seek(&range.end, Bias::Right, &());
1897        let end_excerpt = cursor.item();
1898
1899        start_excerpt
1900            .zip(end_excerpt)
1901            .and_then(|(start_excerpt, end_excerpt)| {
1902                if start_excerpt.id != end_excerpt.id {
1903                    return None;
1904                }
1905
1906                let excerpt_buffer_start =
1907                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
1908                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
1909
1910                let start_in_buffer =
1911                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
1912                let end_in_buffer =
1913                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
1914                let (mut start_bracket_range, mut end_bracket_range) = start_excerpt
1915                    .buffer
1916                    .enclosing_bracket_ranges(start_in_buffer..end_in_buffer)?;
1917
1918                if start_bracket_range.start >= excerpt_buffer_start
1919                    && end_bracket_range.end < excerpt_buffer_end
1920                {
1921                    start_bracket_range.start =
1922                        cursor.start() + (start_bracket_range.start - excerpt_buffer_start);
1923                    start_bracket_range.end =
1924                        cursor.start() + (start_bracket_range.end - excerpt_buffer_start);
1925                    end_bracket_range.start =
1926                        cursor.start() + (end_bracket_range.start - excerpt_buffer_start);
1927                    end_bracket_range.end =
1928                        cursor.start() + (end_bracket_range.end - excerpt_buffer_start);
1929                    Some((start_bracket_range, end_bracket_range))
1930                } else {
1931                    None
1932                }
1933            })
1934    }
1935
1936    pub fn diagnostics_update_count(&self) -> usize {
1937        self.diagnostics_update_count
1938    }
1939
1940    pub fn trailing_excerpt_update_count(&self) -> usize {
1941        self.trailing_excerpt_update_count
1942    }
1943
1944    pub fn language(&self) -> Option<&Arc<Language>> {
1945        self.excerpts
1946            .iter()
1947            .next()
1948            .and_then(|excerpt| excerpt.buffer.language())
1949    }
1950
1951    pub fn is_dirty(&self) -> bool {
1952        self.is_dirty
1953    }
1954
1955    pub fn has_conflict(&self) -> bool {
1956        self.has_conflict
1957    }
1958
1959    pub fn diagnostic_group<'a, O>(
1960        &'a self,
1961        group_id: usize,
1962    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
1963    where
1964        O: text::FromAnchor + 'a,
1965    {
1966        self.as_singleton()
1967            .into_iter()
1968            .flat_map(move |excerpt| excerpt.buffer.diagnostic_group(group_id))
1969    }
1970
1971    pub fn diagnostics_in_range<'a, T, O>(
1972        &'a self,
1973        range: Range<T>,
1974    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
1975    where
1976        T: 'a + ToOffset,
1977        O: 'a + text::FromAnchor,
1978    {
1979        self.as_singleton().into_iter().flat_map(move |excerpt| {
1980            excerpt
1981                .buffer
1982                .diagnostics_in_range(range.start.to_offset(self)..range.end.to_offset(self))
1983        })
1984    }
1985
1986    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
1987        let range = range.start.to_offset(self)..range.end.to_offset(self);
1988
1989        let mut cursor = self.excerpts.cursor::<usize>();
1990        cursor.seek(&range.start, Bias::Right, &());
1991        let start_excerpt = cursor.item();
1992
1993        cursor.seek(&range.end, Bias::Right, &());
1994        let end_excerpt = cursor.item();
1995
1996        start_excerpt
1997            .zip(end_excerpt)
1998            .and_then(|(start_excerpt, end_excerpt)| {
1999                if start_excerpt.id != end_excerpt.id {
2000                    return None;
2001                }
2002
2003                let excerpt_buffer_start =
2004                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
2005                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
2006
2007                let start_in_buffer =
2008                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
2009                let end_in_buffer =
2010                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
2011                let mut ancestor_buffer_range = start_excerpt
2012                    .buffer
2013                    .range_for_syntax_ancestor(start_in_buffer..end_in_buffer)?;
2014                ancestor_buffer_range.start =
2015                    cmp::max(ancestor_buffer_range.start, excerpt_buffer_start);
2016                ancestor_buffer_range.end = cmp::min(ancestor_buffer_range.end, excerpt_buffer_end);
2017
2018                let start = cursor.start() + (ancestor_buffer_range.start - excerpt_buffer_start);
2019                let end = cursor.start() + (ancestor_buffer_range.end - excerpt_buffer_start);
2020                Some(start..end)
2021            })
2022    }
2023
2024    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
2025        let excerpt = self.as_singleton()?;
2026        let outline = excerpt.buffer.outline(theme)?;
2027        Some(Outline::new(
2028            outline
2029                .items
2030                .into_iter()
2031                .map(|item| OutlineItem {
2032                    depth: item.depth,
2033                    range: self.anchor_in_excerpt(excerpt.id.clone(), item.range.start)
2034                        ..self.anchor_in_excerpt(excerpt.id.clone(), item.range.end),
2035                    text: item.text,
2036                    highlight_ranges: item.highlight_ranges,
2037                    name_ranges: item.name_ranges,
2038                })
2039                .collect(),
2040        ))
2041    }
2042
2043    fn buffer_snapshot_for_excerpt<'a>(
2044        &'a self,
2045        excerpt_id: &'a ExcerptId,
2046    ) -> Option<(usize, &'a BufferSnapshot)> {
2047        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2048        cursor.seek(&Some(excerpt_id), Bias::Left, &());
2049        if let Some(excerpt) = cursor.item() {
2050            if excerpt.id == *excerpt_id {
2051                return Some((excerpt.buffer_id, &excerpt.buffer));
2052            }
2053        }
2054        None
2055    }
2056
2057    pub fn remote_selections_in_range<'a>(
2058        &'a self,
2059        range: &'a Range<Anchor>,
2060    ) -> impl 'a + Iterator<Item = (ReplicaId, Selection<Anchor>)> {
2061        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2062        cursor.seek(&Some(&range.start.excerpt_id), Bias::Left, &());
2063        cursor
2064            .take_while(move |excerpt| excerpt.id <= range.end.excerpt_id)
2065            .flat_map(move |excerpt| {
2066                let mut query_range = excerpt.range.start.clone()..excerpt.range.end.clone();
2067                if excerpt.id == range.start.excerpt_id {
2068                    query_range.start = range.start.text_anchor.clone();
2069                }
2070                if excerpt.id == range.end.excerpt_id {
2071                    query_range.end = range.end.text_anchor.clone();
2072                }
2073
2074                excerpt
2075                    .buffer
2076                    .remote_selections_in_range(query_range)
2077                    .flat_map(move |(replica_id, selections)| {
2078                        selections.map(move |selection| {
2079                            let mut start = Anchor {
2080                                buffer_id: excerpt.buffer_id,
2081                                excerpt_id: excerpt.id.clone(),
2082                                text_anchor: selection.start.clone(),
2083                            };
2084                            let mut end = Anchor {
2085                                buffer_id: excerpt.buffer_id,
2086                                excerpt_id: excerpt.id.clone(),
2087                                text_anchor: selection.end.clone(),
2088                            };
2089                            if range.start.cmp(&start, self).unwrap().is_gt() {
2090                                start = range.start.clone();
2091                            }
2092                            if range.end.cmp(&end, self).unwrap().is_lt() {
2093                                end = range.end.clone();
2094                            }
2095
2096                            (
2097                                replica_id,
2098                                Selection {
2099                                    id: selection.id,
2100                                    start,
2101                                    end,
2102                                    reversed: selection.reversed,
2103                                    goal: selection.goal,
2104                                },
2105                            )
2106                        })
2107                    })
2108            })
2109    }
2110}
2111
2112impl History {
2113    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
2114        self.transaction_depth += 1;
2115        if self.transaction_depth == 1 {
2116            let id = self.next_transaction_id.tick();
2117            self.undo_stack.push(Transaction {
2118                id,
2119                buffer_transactions: Default::default(),
2120                first_edit_at: now,
2121                last_edit_at: now,
2122            });
2123            Some(id)
2124        } else {
2125            None
2126        }
2127    }
2128
2129    fn end_transaction(
2130        &mut self,
2131        now: Instant,
2132        buffer_transactions: HashSet<(usize, TransactionId)>,
2133    ) -> bool {
2134        assert_ne!(self.transaction_depth, 0);
2135        self.transaction_depth -= 1;
2136        if self.transaction_depth == 0 {
2137            if buffer_transactions.is_empty() {
2138                self.undo_stack.pop();
2139                false
2140            } else {
2141                let transaction = self.undo_stack.last_mut().unwrap();
2142                transaction.last_edit_at = now;
2143                transaction.buffer_transactions.extend(buffer_transactions);
2144                true
2145            }
2146        } else {
2147            false
2148        }
2149    }
2150
2151    fn pop_undo(&mut self) -> Option<&Transaction> {
2152        assert_eq!(self.transaction_depth, 0);
2153        if let Some(transaction) = self.undo_stack.pop() {
2154            self.redo_stack.push(transaction);
2155            self.redo_stack.last()
2156        } else {
2157            None
2158        }
2159    }
2160
2161    fn pop_redo(&mut self) -> Option<&Transaction> {
2162        assert_eq!(self.transaction_depth, 0);
2163        if let Some(transaction) = self.redo_stack.pop() {
2164            self.undo_stack.push(transaction);
2165            self.undo_stack.last()
2166        } else {
2167            None
2168        }
2169    }
2170
2171    fn group(&mut self) -> Option<TransactionId> {
2172        let mut new_len = self.undo_stack.len();
2173        let mut transactions = self.undo_stack.iter_mut();
2174
2175        if let Some(mut transaction) = transactions.next_back() {
2176            while let Some(prev_transaction) = transactions.next_back() {
2177                if transaction.first_edit_at - prev_transaction.last_edit_at <= self.group_interval
2178                {
2179                    transaction = prev_transaction;
2180                    new_len -= 1;
2181                } else {
2182                    break;
2183                }
2184            }
2185        }
2186
2187        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
2188        if let Some(last_transaction) = transactions_to_keep.last_mut() {
2189            if let Some(transaction) = transactions_to_merge.last() {
2190                last_transaction.last_edit_at = transaction.last_edit_at;
2191            }
2192        }
2193
2194        self.undo_stack.truncate(new_len);
2195        self.undo_stack.last().map(|t| t.id)
2196    }
2197}
2198
2199impl Excerpt {
2200    fn new(
2201        id: ExcerptId,
2202        buffer_id: usize,
2203        buffer: BufferSnapshot,
2204        range: Range<text::Anchor>,
2205        has_trailing_newline: bool,
2206    ) -> Self {
2207        Excerpt {
2208            id,
2209            max_buffer_row: range.end.to_point(&buffer).row,
2210            text_summary: buffer.text_summary_for_range::<TextSummary, _>(range.to_offset(&buffer)),
2211            buffer_id,
2212            buffer,
2213            range,
2214            has_trailing_newline,
2215        }
2216    }
2217
2218    fn chunks_in_range<'a>(
2219        &'a self,
2220        range: Range<usize>,
2221        language_aware: bool,
2222    ) -> ExcerptChunks<'a> {
2223        let content_start = self.range.start.to_offset(&self.buffer);
2224        let chunks_start = content_start + range.start;
2225        let chunks_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2226
2227        let footer_height = if self.has_trailing_newline
2228            && range.start <= self.text_summary.bytes
2229            && range.end > self.text_summary.bytes
2230        {
2231            1
2232        } else {
2233            0
2234        };
2235
2236        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
2237
2238        ExcerptChunks {
2239            content_chunks,
2240            footer_height,
2241        }
2242    }
2243
2244    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
2245        let content_start = self.range.start.to_offset(&self.buffer);
2246        let bytes_start = content_start + range.start;
2247        let bytes_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2248        let footer_height = if self.has_trailing_newline
2249            && range.start <= self.text_summary.bytes
2250            && range.end > self.text_summary.bytes
2251        {
2252            1
2253        } else {
2254            0
2255        };
2256        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
2257
2258        ExcerptBytes {
2259            content_bytes,
2260            footer_height,
2261        }
2262    }
2263
2264    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
2265        if text_anchor
2266            .cmp(&self.range.start, &self.buffer)
2267            .unwrap()
2268            .is_lt()
2269        {
2270            self.range.start.clone()
2271        } else if text_anchor
2272            .cmp(&self.range.end, &self.buffer)
2273            .unwrap()
2274            .is_gt()
2275        {
2276            self.range.end.clone()
2277        } else {
2278            text_anchor
2279        }
2280    }
2281
2282    fn contains(&self, anchor: &Anchor) -> bool {
2283        self.buffer_id == anchor.buffer_id
2284            && self
2285                .range
2286                .start
2287                .cmp(&anchor.text_anchor, &self.buffer)
2288                .unwrap()
2289                .is_le()
2290            && self
2291                .range
2292                .end
2293                .cmp(&anchor.text_anchor, &self.buffer)
2294                .unwrap()
2295                .is_ge()
2296    }
2297}
2298
2299impl fmt::Debug for Excerpt {
2300    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2301        f.debug_struct("Excerpt")
2302            .field("id", &self.id)
2303            .field("buffer_id", &self.buffer_id)
2304            .field("range", &self.range)
2305            .field("text_summary", &self.text_summary)
2306            .field("has_trailing_newline", &self.has_trailing_newline)
2307            .finish()
2308    }
2309}
2310
2311impl sum_tree::Item for Excerpt {
2312    type Summary = ExcerptSummary;
2313
2314    fn summary(&self) -> Self::Summary {
2315        let mut text = self.text_summary.clone();
2316        if self.has_trailing_newline {
2317            text += TextSummary::from("\n");
2318        }
2319        ExcerptSummary {
2320            excerpt_id: self.id.clone(),
2321            max_buffer_row: self.max_buffer_row,
2322            text,
2323        }
2324    }
2325}
2326
2327impl sum_tree::Summary for ExcerptSummary {
2328    type Context = ();
2329
2330    fn add_summary(&mut self, summary: &Self, _: &()) {
2331        debug_assert!(summary.excerpt_id > self.excerpt_id);
2332        self.excerpt_id = summary.excerpt_id.clone();
2333        self.text.add_summary(&summary.text, &());
2334        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
2335    }
2336}
2337
2338impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
2339    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2340        *self += &summary.text;
2341    }
2342}
2343
2344impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
2345    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2346        *self += summary.text.bytes;
2347    }
2348}
2349
2350impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
2351    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2352        Ord::cmp(self, &cursor_location.text.bytes)
2353    }
2354}
2355
2356impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Option<&'a ExcerptId> {
2357    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2358        Ord::cmp(self, &Some(&cursor_location.excerpt_id))
2359    }
2360}
2361
2362impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
2363    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2364        *self += summary.text.lines;
2365    }
2366}
2367
2368impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
2369    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2370        *self += summary.text.lines_utf16
2371    }
2372}
2373
2374impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a ExcerptId> {
2375    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2376        *self = Some(&summary.excerpt_id);
2377    }
2378}
2379
2380impl<'a> MultiBufferRows<'a> {
2381    pub fn seek(&mut self, row: u32) {
2382        self.buffer_row_range = 0..0;
2383
2384        self.excerpts
2385            .seek_forward(&Point::new(row, 0), Bias::Right, &());
2386        if self.excerpts.item().is_none() {
2387            self.excerpts.prev(&());
2388
2389            if self.excerpts.item().is_none() && row == 0 {
2390                self.buffer_row_range = 0..1;
2391                return;
2392            }
2393        }
2394
2395        if let Some(excerpt) = self.excerpts.item() {
2396            let overshoot = row - self.excerpts.start().row;
2397            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer).row;
2398            self.buffer_row_range.start = excerpt_start + overshoot;
2399            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
2400        }
2401    }
2402}
2403
2404impl<'a> Iterator for MultiBufferRows<'a> {
2405    type Item = Option<u32>;
2406
2407    fn next(&mut self) -> Option<Self::Item> {
2408        loop {
2409            if !self.buffer_row_range.is_empty() {
2410                let row = Some(self.buffer_row_range.start);
2411                self.buffer_row_range.start += 1;
2412                return Some(row);
2413            }
2414            self.excerpts.item()?;
2415            self.excerpts.next(&());
2416            let excerpt = self.excerpts.item()?;
2417            self.buffer_row_range.start = excerpt.range.start.to_point(&excerpt.buffer).row;
2418            self.buffer_row_range.end =
2419                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
2420        }
2421    }
2422}
2423
2424impl<'a> MultiBufferChunks<'a> {
2425    pub fn offset(&self) -> usize {
2426        self.range.start
2427    }
2428
2429    pub fn seek(&mut self, offset: usize) {
2430        self.range.start = offset;
2431        self.excerpts.seek(&offset, Bias::Right, &());
2432        if let Some(excerpt) = self.excerpts.item() {
2433            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2434                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
2435                self.language_aware,
2436            ));
2437        } else {
2438            self.excerpt_chunks = None;
2439        }
2440    }
2441}
2442
2443impl<'a> Iterator for MultiBufferChunks<'a> {
2444    type Item = Chunk<'a>;
2445
2446    fn next(&mut self) -> Option<Self::Item> {
2447        if self.range.is_empty() {
2448            None
2449        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
2450            self.range.start += chunk.text.len();
2451            Some(chunk)
2452        } else {
2453            self.excerpts.next(&());
2454            let excerpt = self.excerpts.item()?;
2455            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2456                0..self.range.end - self.excerpts.start(),
2457                self.language_aware,
2458            ));
2459            self.next()
2460        }
2461    }
2462}
2463
2464impl<'a> MultiBufferBytes<'a> {
2465    fn consume(&mut self, len: usize) {
2466        self.range.start += len;
2467        self.chunk = &self.chunk[len..];
2468
2469        if !self.range.is_empty() && self.chunk.is_empty() {
2470            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
2471                self.chunk = chunk;
2472            } else {
2473                self.excerpts.next(&());
2474                if let Some(excerpt) = self.excerpts.item() {
2475                    let mut excerpt_bytes =
2476                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
2477                    self.chunk = excerpt_bytes.next().unwrap();
2478                    self.excerpt_bytes = Some(excerpt_bytes);
2479                }
2480            }
2481        }
2482    }
2483}
2484
2485impl<'a> Iterator for MultiBufferBytes<'a> {
2486    type Item = &'a [u8];
2487
2488    fn next(&mut self) -> Option<Self::Item> {
2489        let chunk = self.chunk;
2490        if chunk.is_empty() {
2491            None
2492        } else {
2493            self.consume(chunk.len());
2494            Some(chunk)
2495        }
2496    }
2497}
2498
2499impl<'a> io::Read for MultiBufferBytes<'a> {
2500    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
2501        let len = cmp::min(buf.len(), self.chunk.len());
2502        buf[..len].copy_from_slice(&self.chunk[..len]);
2503        if len > 0 {
2504            self.consume(len);
2505        }
2506        Ok(len)
2507    }
2508}
2509
2510impl<'a> Iterator for ExcerptBytes<'a> {
2511    type Item = &'a [u8];
2512
2513    fn next(&mut self) -> Option<Self::Item> {
2514        if let Some(chunk) = self.content_bytes.next() {
2515            if !chunk.is_empty() {
2516                return Some(chunk);
2517            }
2518        }
2519
2520        if self.footer_height > 0 {
2521            let result = &NEWLINES[..self.footer_height];
2522            self.footer_height = 0;
2523            return Some(result);
2524        }
2525
2526        None
2527    }
2528}
2529
2530impl<'a> Iterator for ExcerptChunks<'a> {
2531    type Item = Chunk<'a>;
2532
2533    fn next(&mut self) -> Option<Self::Item> {
2534        if let Some(chunk) = self.content_chunks.next() {
2535            return Some(chunk);
2536        }
2537
2538        if self.footer_height > 0 {
2539            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
2540            self.footer_height = 0;
2541            return Some(Chunk {
2542                text,
2543                ..Default::default()
2544            });
2545        }
2546
2547        None
2548    }
2549}
2550
2551impl ToOffset for Point {
2552    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2553        snapshot.point_to_offset(*self)
2554    }
2555}
2556
2557impl ToOffset for PointUtf16 {
2558    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2559        snapshot.point_utf16_to_offset(*self)
2560    }
2561}
2562
2563impl ToOffset for usize {
2564    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2565        assert!(*self <= snapshot.len(), "offset is out of range");
2566        *self
2567    }
2568}
2569
2570impl ToPoint for usize {
2571    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
2572        snapshot.offset_to_point(*self)
2573    }
2574}
2575
2576impl ToPoint for Point {
2577    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
2578        *self
2579    }
2580}
2581
2582impl ToPointUtf16 for usize {
2583    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
2584        snapshot.offset_to_point_utf16(*self)
2585    }
2586}
2587
2588impl ToPointUtf16 for Point {
2589    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
2590        snapshot.point_to_point_utf16(*self)
2591    }
2592}
2593
2594impl ToPointUtf16 for PointUtf16 {
2595    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
2596        *self
2597    }
2598}
2599
2600pub fn char_kind(c: char) -> CharKind {
2601    if c == '\n' {
2602        CharKind::Newline
2603    } else if c.is_whitespace() {
2604        CharKind::Whitespace
2605    } else if c.is_alphanumeric() || c == '_' {
2606        CharKind::Word
2607    } else {
2608        CharKind::Punctuation
2609    }
2610}
2611
2612#[cfg(test)]
2613mod tests {
2614    use super::*;
2615    use gpui::MutableAppContext;
2616    use language::{Buffer, Rope};
2617    use rand::prelude::*;
2618    use std::env;
2619    use text::{Point, RandomCharIter};
2620    use util::test::sample_text;
2621
2622    #[gpui::test]
2623    fn test_singleton_multibuffer(cx: &mut MutableAppContext) {
2624        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2625        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
2626
2627        let snapshot = multibuffer.read(cx).snapshot(cx);
2628        assert_eq!(snapshot.text(), buffer.read(cx).text());
2629
2630        assert_eq!(
2631            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2632            (0..buffer.read(cx).row_count())
2633                .map(Some)
2634                .collect::<Vec<_>>()
2635        );
2636
2637        buffer.update(cx, |buffer, cx| buffer.edit([1..3], "XXX\n", cx));
2638        let snapshot = multibuffer.read(cx).snapshot(cx);
2639
2640        assert_eq!(snapshot.text(), buffer.read(cx).text());
2641        assert_eq!(
2642            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2643            (0..buffer.read(cx).row_count())
2644                .map(Some)
2645                .collect::<Vec<_>>()
2646        );
2647    }
2648
2649    #[gpui::test]
2650    fn test_remote_multibuffer(cx: &mut MutableAppContext) {
2651        let host_buffer = cx.add_model(|cx| Buffer::new(0, "a", cx));
2652        let guest_buffer = cx.add_model(|cx| {
2653            let message = host_buffer.read(cx).to_proto();
2654            Buffer::from_proto(1, message, None, cx).unwrap()
2655        });
2656        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
2657        let snapshot = multibuffer.read(cx).snapshot(cx);
2658        assert_eq!(snapshot.text(), "a");
2659
2660        guest_buffer.update(cx, |buffer, cx| buffer.edit([1..1], "b", cx));
2661        let snapshot = multibuffer.read(cx).snapshot(cx);
2662        assert_eq!(snapshot.text(), "ab");
2663
2664        guest_buffer.update(cx, |buffer, cx| buffer.edit([2..2], "c", cx));
2665        let snapshot = multibuffer.read(cx).snapshot(cx);
2666        assert_eq!(snapshot.text(), "abc");
2667    }
2668
2669    #[gpui::test]
2670    fn test_excerpt_buffer(cx: &mut MutableAppContext) {
2671        let buffer_1 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2672        let buffer_2 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'g'), cx));
2673        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2674
2675        let subscription = multibuffer.update(cx, |multibuffer, cx| {
2676            let subscription = multibuffer.subscribe();
2677            multibuffer.push_excerpts(buffer_1.clone(), [Point::new(1, 2)..Point::new(2, 5)], cx);
2678            assert_eq!(
2679                subscription.consume().into_inner(),
2680                [Edit {
2681                    old: 0..0,
2682                    new: 0..10
2683                }]
2684            );
2685
2686            multibuffer.push_excerpts(buffer_1.clone(), [Point::new(3, 3)..Point::new(4, 4)], cx);
2687            multibuffer.push_excerpts(buffer_2.clone(), [Point::new(3, 1)..Point::new(3, 3)], cx);
2688            assert_eq!(
2689                subscription.consume().into_inner(),
2690                [Edit {
2691                    old: 10..10,
2692                    new: 10..22
2693                }]
2694            );
2695
2696            subscription
2697        });
2698
2699        let snapshot = multibuffer.read(cx).snapshot(cx);
2700        assert_eq!(
2701            snapshot.text(),
2702            concat!(
2703                "bbbb\n",  // Preserve newlines
2704                "ccccc\n", //
2705                "ddd\n",   //
2706                "eeee\n",  //
2707                "jj"       //
2708            )
2709        );
2710        assert_eq!(
2711            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2712            [Some(1), Some(2), Some(3), Some(4), Some(3)]
2713        );
2714        assert_eq!(
2715            snapshot.buffer_rows(2).collect::<Vec<_>>(),
2716            [Some(3), Some(4), Some(3)]
2717        );
2718        assert_eq!(snapshot.buffer_rows(4).collect::<Vec<_>>(), [Some(3)]);
2719        assert_eq!(snapshot.buffer_rows(5).collect::<Vec<_>>(), []);
2720
2721        assert_eq!(
2722            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
2723            &[
2724                (0, "bbbb\nccccc".to_string(), true),
2725                (2, "ddd\neeee".to_string(), false),
2726                (4, "jj".to_string(), true),
2727            ]
2728        );
2729        assert_eq!(
2730            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
2731            &[(0, "bbbb\nccccc".to_string(), true)]
2732        );
2733        assert_eq!(
2734            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
2735            &[]
2736        );
2737        assert_eq!(
2738            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
2739            &[]
2740        );
2741        assert_eq!(
2742            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
2743            &[(2, "ddd\neeee".to_string(), false)]
2744        );
2745        assert_eq!(
2746            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
2747            &[(2, "ddd\neeee".to_string(), false)]
2748        );
2749        assert_eq!(
2750            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
2751            &[(2, "ddd\neeee".to_string(), false)]
2752        );
2753        assert_eq!(
2754            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
2755            &[(4, "jj".to_string(), true)]
2756        );
2757        assert_eq!(
2758            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
2759            &[]
2760        );
2761
2762        buffer_1.update(cx, |buffer, cx| {
2763            buffer.edit(
2764                [
2765                    Point::new(0, 0)..Point::new(0, 0),
2766                    Point::new(2, 1)..Point::new(2, 3),
2767                ],
2768                "\n",
2769                cx,
2770            );
2771        });
2772
2773        let snapshot = multibuffer.read(cx).snapshot(cx);
2774        assert_eq!(
2775            snapshot.text(),
2776            concat!(
2777                "bbbb\n", // Preserve newlines
2778                "c\n",    //
2779                "cc\n",   //
2780                "ddd\n",  //
2781                "eeee\n", //
2782                "jj"      //
2783            )
2784        );
2785
2786        assert_eq!(
2787            subscription.consume().into_inner(),
2788            [Edit {
2789                old: 6..8,
2790                new: 6..7
2791            }]
2792        );
2793
2794        let snapshot = multibuffer.read(cx).snapshot(cx);
2795        assert_eq!(
2796            snapshot.clip_point(Point::new(0, 5), Bias::Left),
2797            Point::new(0, 4)
2798        );
2799        assert_eq!(
2800            snapshot.clip_point(Point::new(0, 5), Bias::Right),
2801            Point::new(0, 4)
2802        );
2803        assert_eq!(
2804            snapshot.clip_point(Point::new(5, 1), Bias::Right),
2805            Point::new(5, 1)
2806        );
2807        assert_eq!(
2808            snapshot.clip_point(Point::new(5, 2), Bias::Right),
2809            Point::new(5, 2)
2810        );
2811        assert_eq!(
2812            snapshot.clip_point(Point::new(5, 3), Bias::Right),
2813            Point::new(5, 2)
2814        );
2815
2816        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
2817            let buffer_2_excerpt_id = multibuffer.excerpt_ids_for_buffer(&buffer_2)[0].clone();
2818            multibuffer.remove_excerpts(&[buffer_2_excerpt_id], cx);
2819            multibuffer.snapshot(cx)
2820        });
2821
2822        assert_eq!(
2823            snapshot.text(),
2824            concat!(
2825                "bbbb\n", // Preserve newlines
2826                "c\n",    //
2827                "cc\n",   //
2828                "ddd\n",  //
2829                "eeee",   //
2830            )
2831        );
2832
2833        fn boundaries_in_range(
2834            range: Range<Point>,
2835            snapshot: &MultiBufferSnapshot,
2836        ) -> Vec<(u32, String, bool)> {
2837            snapshot
2838                .excerpt_boundaries_in_range(range)
2839                .map(|boundary| {
2840                    (
2841                        boundary.row,
2842                        boundary
2843                            .buffer
2844                            .text_for_range(boundary.range)
2845                            .collect::<String>(),
2846                        boundary.starts_new_buffer,
2847                    )
2848                })
2849                .collect::<Vec<_>>()
2850        }
2851    }
2852
2853    #[gpui::test]
2854    fn test_empty_excerpt_buffer(cx: &mut MutableAppContext) {
2855        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2856
2857        let snapshot = multibuffer.read(cx).snapshot(cx);
2858        assert_eq!(snapshot.text(), "");
2859        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), &[Some(0)]);
2860        assert_eq!(snapshot.buffer_rows(1).collect::<Vec<_>>(), &[]);
2861    }
2862
2863    #[gpui::test]
2864    fn test_singleton_multibuffer_anchors(cx: &mut MutableAppContext) {
2865        let buffer = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
2866        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
2867        let old_snapshot = multibuffer.read(cx).snapshot(cx);
2868        buffer.update(cx, |buffer, cx| {
2869            buffer.edit([0..0], "X", cx);
2870            buffer.edit([5..5], "Y", cx);
2871        });
2872        let new_snapshot = multibuffer.read(cx).snapshot(cx);
2873
2874        assert_eq!(old_snapshot.text(), "abcd");
2875        assert_eq!(new_snapshot.text(), "XabcdY");
2876
2877        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
2878        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
2879        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
2880        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
2881    }
2882
2883    #[gpui::test]
2884    fn test_multibuffer_anchors(cx: &mut MutableAppContext) {
2885        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
2886        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "efghi", cx));
2887        let multibuffer = cx.add_model(|cx| {
2888            let mut multibuffer = MultiBuffer::new(0);
2889            multibuffer.push_excerpts(buffer_1.clone(), [0..4], cx);
2890            multibuffer.push_excerpts(buffer_2.clone(), [0..5], cx);
2891            multibuffer
2892        });
2893        let old_snapshot = multibuffer.read(cx).snapshot(cx);
2894
2895        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
2896        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
2897        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
2898        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
2899        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
2900        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
2901
2902        buffer_1.update(cx, |buffer, cx| {
2903            buffer.edit([0..0], "W", cx);
2904            buffer.edit([5..5], "X", cx);
2905        });
2906        buffer_2.update(cx, |buffer, cx| {
2907            buffer.edit([0..0], "Y", cx);
2908            buffer.edit([6..0], "Z", cx);
2909        });
2910        let new_snapshot = multibuffer.read(cx).snapshot(cx);
2911
2912        assert_eq!(old_snapshot.text(), "abcd\nefghi");
2913        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
2914
2915        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
2916        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
2917        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
2918        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
2919        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
2920        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
2921        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
2922        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
2923        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
2924        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
2925    }
2926
2927    #[gpui::test]
2928    fn test_multibuffer_resolving_anchors_after_replacing_their_excerpts(
2929        cx: &mut MutableAppContext,
2930    ) {
2931        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
2932        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "ABCDEFGHIJKLMNOP", cx));
2933        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2934
2935        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
2936        // Add an excerpt from buffer 1 that spans this new insertion.
2937        buffer_1.update(cx, |buffer, cx| buffer.edit([4..4], "123", cx));
2938        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
2939            multibuffer
2940                .push_excerpts(buffer_1.clone(), [0..7], cx)
2941                .pop()
2942                .unwrap()
2943        });
2944
2945        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
2946        assert_eq!(snapshot_1.text(), "abcd123");
2947
2948        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
2949        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
2950            multibuffer.remove_excerpts([&excerpt_id_1], cx);
2951            let mut ids = multibuffer
2952                .push_excerpts(buffer_2.clone(), [0..4, 6..10, 12..16], cx)
2953                .into_iter();
2954            (ids.next().unwrap(), ids.next().unwrap())
2955        });
2956        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
2957        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
2958
2959        // The old excerpt id has been reused.
2960        assert_eq!(excerpt_id_2, excerpt_id_1);
2961
2962        // Resolve some anchors from the previous snapshot in the new snapshot.
2963        // Although there is still an excerpt with the same id, it is for
2964        // a different buffer, so we don't attempt to resolve the old text
2965        // anchor in the new buffer.
2966        assert_eq!(
2967            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
2968            0
2969        );
2970        assert_eq!(
2971            snapshot_2.summaries_for_anchors::<usize, _>(&[
2972                snapshot_1.anchor_before(2),
2973                snapshot_1.anchor_after(3)
2974            ]),
2975            vec![0, 0]
2976        );
2977        let refresh =
2978            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
2979        assert_eq!(
2980            refresh,
2981            &[
2982                (0, snapshot_2.anchor_before(0), false),
2983                (1, snapshot_2.anchor_after(0), false),
2984            ]
2985        );
2986
2987        // Replace the middle excerpt with a smaller excerpt in buffer 2,
2988        // that intersects the old excerpt.
2989        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
2990            multibuffer.remove_excerpts([&excerpt_id_3], cx);
2991            multibuffer
2992                .insert_excerpts_after(&excerpt_id_3, buffer_2.clone(), [5..8], cx)
2993                .pop()
2994                .unwrap()
2995        });
2996
2997        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
2998        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
2999        assert_ne!(excerpt_id_5, excerpt_id_3);
3000
3001        // Resolve some anchors from the previous snapshot in the new snapshot.
3002        // The anchor in the middle excerpt snaps to the beginning of the
3003        // excerpt, since it is not
3004        let anchors = [
3005            snapshot_2.anchor_before(0),
3006            snapshot_2.anchor_after(2),
3007            snapshot_2.anchor_after(6),
3008            snapshot_2.anchor_after(14),
3009        ];
3010        assert_eq!(
3011            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
3012            &[0, 2, 9, 13]
3013        );
3014
3015        let new_anchors = snapshot_3.refresh_anchors(&anchors);
3016        assert_eq!(
3017            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
3018            &[(0, true), (1, true), (2, true), (3, true)]
3019        );
3020        assert_eq!(
3021            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
3022            &[0, 2, 7, 13]
3023        );
3024    }
3025
3026    #[gpui::test(iterations = 100)]
3027    fn test_random_multibuffer(cx: &mut MutableAppContext, mut rng: StdRng) {
3028        let operations = env::var("OPERATIONS")
3029            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
3030            .unwrap_or(10);
3031
3032        let mut buffers: Vec<ModelHandle<Buffer>> = Vec::new();
3033        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3034        let mut excerpt_ids = Vec::new();
3035        let mut expected_excerpts = Vec::<(ModelHandle<Buffer>, Range<text::Anchor>)>::new();
3036        let mut anchors = Vec::new();
3037        let mut old_versions = Vec::new();
3038
3039        for _ in 0..operations {
3040            match rng.gen_range(0..100) {
3041                0..=19 if !buffers.is_empty() => {
3042                    let buffer = buffers.choose(&mut rng).unwrap();
3043                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
3044                }
3045                20..=29 if !expected_excerpts.is_empty() => {
3046                    let mut ids_to_remove = vec![];
3047                    for _ in 0..rng.gen_range(1..=3) {
3048                        if expected_excerpts.is_empty() {
3049                            break;
3050                        }
3051
3052                        let ix = rng.gen_range(0..expected_excerpts.len());
3053                        ids_to_remove.push(excerpt_ids.remove(ix));
3054                        let (buffer, range) = expected_excerpts.remove(ix);
3055                        let buffer = buffer.read(cx);
3056                        log::info!(
3057                            "Removing excerpt {}: {:?}",
3058                            ix,
3059                            buffer
3060                                .text_for_range(range.to_offset(&buffer))
3061                                .collect::<String>(),
3062                        );
3063                    }
3064                    ids_to_remove.sort_unstable();
3065                    multibuffer.update(cx, |multibuffer, cx| {
3066                        multibuffer.remove_excerpts(&ids_to_remove, cx)
3067                    });
3068                }
3069                30..=39 if !expected_excerpts.is_empty() => {
3070                    let multibuffer = multibuffer.read(cx).read(cx);
3071                    let offset =
3072                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
3073                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
3074                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
3075                    anchors.push(multibuffer.anchor_at(offset, bias));
3076                    anchors.sort_by(|a, b| a.cmp(&b, &multibuffer).unwrap());
3077                }
3078                40..=44 if !anchors.is_empty() => {
3079                    let multibuffer = multibuffer.read(cx).read(cx);
3080
3081                    anchors = multibuffer
3082                        .refresh_anchors(&anchors)
3083                        .into_iter()
3084                        .map(|a| a.1)
3085                        .collect();
3086
3087                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
3088                    // overshoot its boundaries.
3089                    let mut cursor = multibuffer.excerpts.cursor::<Option<&ExcerptId>>();
3090                    for anchor in &anchors {
3091                        if anchor.excerpt_id == ExcerptId::min()
3092                            || anchor.excerpt_id == ExcerptId::max()
3093                        {
3094                            continue;
3095                        }
3096
3097                        cursor.seek_forward(&Some(&anchor.excerpt_id), Bias::Left, &());
3098                        let excerpt = cursor.item().unwrap();
3099                        assert_eq!(excerpt.id, anchor.excerpt_id);
3100                        assert!(excerpt.contains(anchor));
3101                    }
3102                }
3103                _ => {
3104                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
3105                        let base_text = RandomCharIter::new(&mut rng).take(10).collect::<String>();
3106                        buffers.push(cx.add_model(|cx| Buffer::new(0, base_text, cx)));
3107                        buffers.last().unwrap()
3108                    } else {
3109                        buffers.choose(&mut rng).unwrap()
3110                    };
3111
3112                    let buffer = buffer_handle.read(cx);
3113                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3114                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3115                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
3116                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
3117                    let prev_excerpt_id = excerpt_ids
3118                        .get(prev_excerpt_ix)
3119                        .cloned()
3120                        .unwrap_or(ExcerptId::max());
3121                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
3122
3123                    log::info!(
3124                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
3125                        excerpt_ix,
3126                        expected_excerpts.len(),
3127                        buffer_handle.id(),
3128                        buffer.text(),
3129                        start_ix..end_ix,
3130                        &buffer.text()[start_ix..end_ix]
3131                    );
3132
3133                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
3134                        multibuffer
3135                            .insert_excerpts_after(
3136                                &prev_excerpt_id,
3137                                buffer_handle.clone(),
3138                                [start_ix..end_ix],
3139                                cx,
3140                            )
3141                            .pop()
3142                            .unwrap()
3143                    });
3144
3145                    excerpt_ids.insert(excerpt_ix, excerpt_id);
3146                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
3147                }
3148            }
3149
3150            if rng.gen_bool(0.3) {
3151                multibuffer.update(cx, |multibuffer, cx| {
3152                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
3153                })
3154            }
3155
3156            let snapshot = multibuffer.read(cx).snapshot(cx);
3157
3158            let mut excerpt_starts = Vec::new();
3159            let mut expected_text = String::new();
3160            let mut expected_buffer_rows = Vec::new();
3161            for (buffer, range) in &expected_excerpts {
3162                let buffer = buffer.read(cx);
3163                let buffer_range = range.to_offset(buffer);
3164
3165                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
3166                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
3167                expected_text.push('\n');
3168
3169                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
3170                    ..=buffer.offset_to_point(buffer_range.end).row;
3171                for row in buffer_row_range {
3172                    expected_buffer_rows.push(Some(row));
3173                }
3174            }
3175            // Remove final trailing newline.
3176            if !expected_excerpts.is_empty() {
3177                expected_text.pop();
3178            }
3179
3180            // Always report one buffer row
3181            if expected_buffer_rows.is_empty() {
3182                expected_buffer_rows.push(Some(0));
3183            }
3184
3185            assert_eq!(snapshot.text(), expected_text);
3186            log::info!("MultiBuffer text: {:?}", expected_text);
3187
3188            assert_eq!(
3189                snapshot.buffer_rows(0).collect::<Vec<_>>(),
3190                expected_buffer_rows,
3191            );
3192
3193            for _ in 0..5 {
3194                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
3195                assert_eq!(
3196                    snapshot.buffer_rows(start_row as u32).collect::<Vec<_>>(),
3197                    &expected_buffer_rows[start_row..],
3198                    "buffer_rows({})",
3199                    start_row
3200                );
3201            }
3202
3203            assert_eq!(
3204                snapshot.max_buffer_row(),
3205                expected_buffer_rows
3206                    .into_iter()
3207                    .filter_map(|r| r)
3208                    .max()
3209                    .unwrap()
3210            );
3211
3212            let mut excerpt_starts = excerpt_starts.into_iter();
3213            for (buffer, range) in &expected_excerpts {
3214                let buffer_id = buffer.id();
3215                let buffer = buffer.read(cx);
3216                let buffer_range = range.to_offset(buffer);
3217                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
3218                let buffer_start_point_utf16 =
3219                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
3220
3221                let excerpt_start = excerpt_starts.next().unwrap();
3222                let mut offset = excerpt_start.bytes;
3223                let mut buffer_offset = buffer_range.start;
3224                let mut point = excerpt_start.lines;
3225                let mut buffer_point = buffer_start_point;
3226                let mut point_utf16 = excerpt_start.lines_utf16;
3227                let mut buffer_point_utf16 = buffer_start_point_utf16;
3228                for ch in buffer
3229                    .snapshot()
3230                    .chunks(buffer_range.clone(), false)
3231                    .flat_map(|c| c.text.chars())
3232                {
3233                    for _ in 0..ch.len_utf8() {
3234                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
3235                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
3236                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
3237                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
3238                        assert_eq!(
3239                            left_offset,
3240                            excerpt_start.bytes + (buffer_left_offset - buffer_range.start),
3241                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
3242                            offset,
3243                            buffer_id,
3244                            buffer_offset,
3245                        );
3246                        assert_eq!(
3247                            right_offset,
3248                            excerpt_start.bytes + (buffer_right_offset - buffer_range.start),
3249                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
3250                            offset,
3251                            buffer_id,
3252                            buffer_offset,
3253                        );
3254
3255                        let left_point = snapshot.clip_point(point, Bias::Left);
3256                        let right_point = snapshot.clip_point(point, Bias::Right);
3257                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
3258                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
3259                        assert_eq!(
3260                            left_point,
3261                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
3262                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
3263                            point,
3264                            buffer_id,
3265                            buffer_point,
3266                        );
3267                        assert_eq!(
3268                            right_point,
3269                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
3270                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
3271                            point,
3272                            buffer_id,
3273                            buffer_point,
3274                        );
3275
3276                        assert_eq!(
3277                            snapshot.point_to_offset(left_point),
3278                            left_offset,
3279                            "point_to_offset({:?})",
3280                            left_point,
3281                        );
3282                        assert_eq!(
3283                            snapshot.offset_to_point(left_offset),
3284                            left_point,
3285                            "offset_to_point({:?})",
3286                            left_offset,
3287                        );
3288
3289                        offset += 1;
3290                        buffer_offset += 1;
3291                        if ch == '\n' {
3292                            point += Point::new(1, 0);
3293                            buffer_point += Point::new(1, 0);
3294                        } else {
3295                            point += Point::new(0, 1);
3296                            buffer_point += Point::new(0, 1);
3297                        }
3298                    }
3299
3300                    for _ in 0..ch.len_utf16() {
3301                        let left_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Left);
3302                        let right_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Right);
3303                        let buffer_left_point_utf16 =
3304                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Left);
3305                        let buffer_right_point_utf16 =
3306                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Right);
3307                        assert_eq!(
3308                            left_point_utf16,
3309                            excerpt_start.lines_utf16
3310                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
3311                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
3312                            point_utf16,
3313                            buffer_id,
3314                            buffer_point_utf16,
3315                        );
3316                        assert_eq!(
3317                            right_point_utf16,
3318                            excerpt_start.lines_utf16
3319                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
3320                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
3321                            point_utf16,
3322                            buffer_id,
3323                            buffer_point_utf16,
3324                        );
3325
3326                        if ch == '\n' {
3327                            point_utf16 += PointUtf16::new(1, 0);
3328                            buffer_point_utf16 += PointUtf16::new(1, 0);
3329                        } else {
3330                            point_utf16 += PointUtf16::new(0, 1);
3331                            buffer_point_utf16 += PointUtf16::new(0, 1);
3332                        }
3333                    }
3334                }
3335            }
3336
3337            for (row, line) in expected_text.split('\n').enumerate() {
3338                assert_eq!(
3339                    snapshot.line_len(row as u32),
3340                    line.len() as u32,
3341                    "line_len({}).",
3342                    row
3343                );
3344            }
3345
3346            let text_rope = Rope::from(expected_text.as_str());
3347            for _ in 0..10 {
3348                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3349                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3350
3351                let text_for_range = snapshot
3352                    .text_for_range(start_ix..end_ix)
3353                    .collect::<String>();
3354                assert_eq!(
3355                    text_for_range,
3356                    &expected_text[start_ix..end_ix],
3357                    "incorrect text for range {:?}",
3358                    start_ix..end_ix
3359                );
3360
3361                let excerpted_buffer_ranges =
3362                    multibuffer.read(cx).excerpted_buffers(start_ix..end_ix, cx);
3363                let excerpted_buffers_text = excerpted_buffer_ranges
3364                    .into_iter()
3365                    .map(|(buffer, buffer_range)| {
3366                        buffer
3367                            .read(cx)
3368                            .text_for_range(buffer_range)
3369                            .collect::<String>()
3370                    })
3371                    .collect::<Vec<_>>()
3372                    .join("\n");
3373                assert_eq!(excerpted_buffers_text, text_for_range);
3374
3375                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
3376                assert_eq!(
3377                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
3378                    expected_summary,
3379                    "incorrect summary for range {:?}",
3380                    start_ix..end_ix
3381                );
3382            }
3383
3384            // Anchor resolution
3385            for (anchor, resolved_offset) in anchors
3386                .iter()
3387                .zip(snapshot.summaries_for_anchors::<usize, _>(&anchors))
3388            {
3389                assert!(resolved_offset <= snapshot.len());
3390                assert_eq!(
3391                    snapshot.summary_for_anchor::<usize>(anchor),
3392                    resolved_offset
3393                );
3394            }
3395
3396            for _ in 0..10 {
3397                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3398                assert_eq!(
3399                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
3400                    expected_text[..end_ix].chars().rev().collect::<String>(),
3401                );
3402            }
3403
3404            for _ in 0..10 {
3405                let end_ix = rng.gen_range(0..=text_rope.len());
3406                let start_ix = rng.gen_range(0..=end_ix);
3407                assert_eq!(
3408                    snapshot
3409                        .bytes_in_range(start_ix..end_ix)
3410                        .flatten()
3411                        .copied()
3412                        .collect::<Vec<_>>(),
3413                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
3414                    "bytes_in_range({:?})",
3415                    start_ix..end_ix,
3416                );
3417            }
3418        }
3419
3420        let snapshot = multibuffer.read(cx).snapshot(cx);
3421        for (old_snapshot, subscription) in old_versions {
3422            let edits = subscription.consume().into_inner();
3423
3424            log::info!(
3425                "applying subscription edits to old text: {:?}: {:?}",
3426                old_snapshot.text(),
3427                edits,
3428            );
3429
3430            let mut text = old_snapshot.text();
3431            for edit in edits {
3432                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
3433                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
3434            }
3435            assert_eq!(text.to_string(), snapshot.text());
3436        }
3437    }
3438
3439    #[gpui::test]
3440    fn test_history(cx: &mut MutableAppContext) {
3441        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "1234", cx));
3442        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "5678", cx));
3443        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3444        let group_interval = multibuffer.read(cx).history.group_interval;
3445        multibuffer.update(cx, |multibuffer, cx| {
3446            multibuffer.push_excerpts(buffer_1.clone(), [0..buffer_1.read(cx).len()], cx);
3447            multibuffer.push_excerpts(buffer_2.clone(), [0..buffer_2.read(cx).len()], cx);
3448        });
3449
3450        let mut now = Instant::now();
3451
3452        multibuffer.update(cx, |multibuffer, cx| {
3453            multibuffer.start_transaction_at(now, cx);
3454            multibuffer.edit(
3455                [
3456                    Point::new(0, 0)..Point::new(0, 0),
3457                    Point::new(1, 0)..Point::new(1, 0),
3458                ],
3459                "A",
3460                cx,
3461            );
3462            multibuffer.edit(
3463                [
3464                    Point::new(0, 1)..Point::new(0, 1),
3465                    Point::new(1, 1)..Point::new(1, 1),
3466                ],
3467                "B",
3468                cx,
3469            );
3470            multibuffer.end_transaction_at(now, cx);
3471            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3472
3473            now += 2 * group_interval;
3474            multibuffer.start_transaction_at(now, cx);
3475            multibuffer.edit([2..2], "C", cx);
3476            multibuffer.end_transaction_at(now, cx);
3477            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3478
3479            multibuffer.undo(cx);
3480            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3481
3482            multibuffer.undo(cx);
3483            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3484
3485            multibuffer.redo(cx);
3486            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3487
3488            multibuffer.redo(cx);
3489            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3490
3491            buffer_1.update(cx, |buffer_1, cx| buffer_1.undo(cx));
3492            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3493
3494            multibuffer.undo(cx);
3495            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3496
3497            multibuffer.redo(cx);
3498            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3499
3500            multibuffer.redo(cx);
3501            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3502
3503            multibuffer.undo(cx);
3504            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3505
3506            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
3507            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3508
3509            multibuffer.undo(cx);
3510            assert_eq!(multibuffer.read(cx).text(), "C1234\n5678");
3511        });
3512    }
3513}