multi_buffer.rs

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