multi_buffer.rs

   1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt};
   4use anyhow::Result;
   5use clock::ReplicaId;
   6use collections::{Bound, HashMap};
   7use gpui::{AppContext, Entity, ModelContext, ModelHandle, Task};
   8pub use language::Completion;
   9use language::{
  10    Buffer, BufferChunks, BufferSnapshot, Chunk, DiagnosticEntry, Event, File, Language, Outline,
  11    OutlineItem, Selection, ToOffset as _, ToPoint as _, ToPointUtf16 as _, TransactionId,
  12};
  13use std::{
  14    cell::{Ref, RefCell},
  15    cmp, fmt, io,
  16    iter::{self, FromIterator},
  17    ops::{Range, RangeBounds, Sub},
  18    str,
  19    sync::Arc,
  20    time::{Duration, Instant},
  21};
  22use sum_tree::{Bias, Cursor, SumTree};
  23use text::{
  24    locator::Locator,
  25    rope::TextDimension,
  26    subscription::{Subscription, Topic},
  27    AnchorRangeExt as _, Edit, Point, PointUtf16, TextSummary,
  28};
  29use theme::SyntaxTheme;
  30
  31const NEWLINES: &'static [u8] = &[b'\n'; u8::MAX as usize];
  32
  33pub type ExcerptId = Locator;
  34
  35pub struct MultiBuffer {
  36    snapshot: RefCell<MultiBufferSnapshot>,
  37    buffers: RefCell<HashMap<usize, BufferState>>,
  38    subscriptions: Topic,
  39    singleton: bool,
  40    replica_id: ReplicaId,
  41    history: History,
  42    title: Option<String>,
  43}
  44
  45struct History {
  46    next_transaction_id: TransactionId,
  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: TransactionId,
  63    buffer_transactions: HashMap<usize, text::TransactionId>,
  64    first_edit_at: Instant,
  65    last_edit_at: Instant,
  66    suppress_grouping: bool,
  67}
  68
  69pub trait ToOffset: 'static + fmt::Debug {
  70    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
  71}
  72
  73pub trait ToPoint: 'static + fmt::Debug {
  74    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
  75}
  76
  77pub trait ToPointUtf16: 'static + fmt::Debug {
  78    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
  79}
  80
  81struct BufferState {
  82    buffer: ModelHandle<Buffer>,
  83    last_version: clock::Global,
  84    last_parse_count: usize,
  85    last_selections_update_count: usize,
  86    last_diagnostics_update_count: usize,
  87    last_file_update_count: usize,
  88    excerpts: Vec<ExcerptId>,
  89    _subscriptions: [gpui::Subscription; 2],
  90}
  91
  92#[derive(Clone, Default)]
  93pub struct MultiBufferSnapshot {
  94    singleton: bool,
  95    excerpts: SumTree<Excerpt>,
  96    parse_count: usize,
  97    diagnostics_update_count: usize,
  98    trailing_excerpt_update_count: usize,
  99    is_dirty: bool,
 100    has_conflict: bool,
 101}
 102
 103pub struct ExcerptBoundary {
 104    pub row: u32,
 105    pub buffer: BufferSnapshot,
 106    pub range: Range<text::Anchor>,
 107    pub starts_new_buffer: bool,
 108}
 109
 110#[derive(Clone)]
 111struct Excerpt {
 112    id: ExcerptId,
 113    buffer_id: usize,
 114    buffer: BufferSnapshot,
 115    range: Range<text::Anchor>,
 116    max_buffer_row: u32,
 117    text_summary: TextSummary,
 118    has_trailing_newline: bool,
 119}
 120
 121#[derive(Clone, Debug, Default)]
 122struct ExcerptSummary {
 123    excerpt_id: ExcerptId,
 124    max_buffer_row: u32,
 125    text: TextSummary,
 126}
 127
 128pub struct MultiBufferRows<'a> {
 129    buffer_row_range: Range<u32>,
 130    excerpts: Cursor<'a, Excerpt, Point>,
 131}
 132
 133pub struct MultiBufferChunks<'a> {
 134    range: Range<usize>,
 135    excerpts: Cursor<'a, Excerpt, usize>,
 136    excerpt_chunks: Option<ExcerptChunks<'a>>,
 137    language_aware: bool,
 138}
 139
 140pub struct MultiBufferBytes<'a> {
 141    range: Range<usize>,
 142    excerpts: Cursor<'a, Excerpt, usize>,
 143    excerpt_bytes: Option<ExcerptBytes<'a>>,
 144    chunk: &'a [u8],
 145}
 146
 147struct ExcerptChunks<'a> {
 148    content_chunks: BufferChunks<'a>,
 149    footer_height: usize,
 150}
 151
 152struct ExcerptBytes<'a> {
 153    content_bytes: language::rope::Bytes<'a>,
 154    footer_height: usize,
 155}
 156
 157impl MultiBuffer {
 158    pub fn new(replica_id: ReplicaId) -> Self {
 159        Self {
 160            snapshot: Default::default(),
 161            buffers: Default::default(),
 162            subscriptions: Default::default(),
 163            singleton: false,
 164            replica_id,
 165            history: History {
 166                next_transaction_id: Default::default(),
 167                undo_stack: Default::default(),
 168                redo_stack: Default::default(),
 169                transaction_depth: 0,
 170                group_interval: Duration::from_millis(300),
 171            },
 172            title: Default::default(),
 173        }
 174    }
 175
 176    pub fn with_title(mut self, title: String) -> Self {
 177        self.title = Some(title);
 178        self
 179    }
 180
 181    pub fn singleton(buffer: ModelHandle<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 182        let mut this = Self::new(buffer.read(cx).replica_id());
 183        this.singleton = true;
 184        this.push_excerpts(buffer, [text::Anchor::min()..text::Anchor::max()], cx);
 185        this.snapshot.borrow_mut().singleton = true;
 186        this
 187    }
 188
 189    #[cfg(any(test, feature = "test-support"))]
 190    pub fn build_simple(text: &str, cx: &mut gpui::MutableAppContext) -> ModelHandle<Self> {
 191        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
 192        cx.add_model(|cx| Self::singleton(buffer, cx))
 193    }
 194
 195    #[cfg(any(test, feature = "test-support"))]
 196    pub fn build_random(
 197        rng: &mut impl rand::Rng,
 198        cx: &mut gpui::MutableAppContext,
 199    ) -> ModelHandle<Self> {
 200        cx.add_model(|cx| {
 201            let mut multibuffer = MultiBuffer::new(0);
 202            let mutation_count = rng.gen_range(1..=5);
 203            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
 204            multibuffer
 205        })
 206    }
 207
 208    pub fn replica_id(&self) -> ReplicaId {
 209        self.replica_id
 210    }
 211
 212    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 213        self.sync(cx);
 214        self.snapshot.borrow().clone()
 215    }
 216
 217    pub fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 218        self.sync(cx);
 219        self.snapshot.borrow()
 220    }
 221
 222    pub fn as_singleton(&self) -> Option<ModelHandle<Buffer>> {
 223        if self.singleton {
 224            return Some(
 225                self.buffers
 226                    .borrow()
 227                    .values()
 228                    .next()
 229                    .unwrap()
 230                    .buffer
 231                    .clone(),
 232            );
 233        } else {
 234            None
 235        }
 236    }
 237
 238    pub fn is_singleton(&self) -> bool {
 239        self.singleton
 240    }
 241
 242    pub fn subscribe(&mut self) -> Subscription {
 243        self.subscriptions.subscribe()
 244    }
 245
 246    pub fn edit<I, S, T>(&mut self, ranges: I, new_text: T, cx: &mut ModelContext<Self>)
 247    where
 248        I: IntoIterator<Item = Range<S>>,
 249        S: ToOffset,
 250        T: Into<String>,
 251    {
 252        self.edit_internal(ranges, new_text, false, cx)
 253    }
 254
 255    pub fn edit_with_autoindent<I, S, T>(
 256        &mut self,
 257        ranges: I,
 258        new_text: T,
 259        cx: &mut ModelContext<Self>,
 260    ) where
 261        I: IntoIterator<Item = Range<S>>,
 262        S: ToOffset,
 263        T: Into<String>,
 264    {
 265        self.edit_internal(ranges, new_text, true, cx)
 266    }
 267
 268    pub fn edit_internal<I, S, T>(
 269        &mut self,
 270        ranges_iter: I,
 271        new_text: T,
 272        autoindent: bool,
 273        cx: &mut ModelContext<Self>,
 274    ) where
 275        I: IntoIterator<Item = Range<S>>,
 276        S: ToOffset,
 277        T: Into<String>,
 278    {
 279        if self.buffers.borrow().is_empty() {
 280            return;
 281        }
 282
 283        if let Some(buffer) = self.as_singleton() {
 284            let snapshot = self.read(cx);
 285            let ranges = ranges_iter
 286                .into_iter()
 287                .map(|range| range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot));
 288            return buffer.update(cx, |buffer, cx| {
 289                if autoindent {
 290                    buffer.edit_with_autoindent(ranges, new_text, cx);
 291                } else {
 292                    buffer.edit(ranges, new_text, cx);
 293                }
 294            });
 295        }
 296
 297        let snapshot = self.read(cx);
 298        let mut buffer_edits: HashMap<usize, Vec<(Range<usize>, bool)>> = Default::default();
 299        let mut cursor = snapshot.excerpts.cursor::<usize>();
 300        for range in ranges_iter {
 301            let start = range.start.to_offset(&snapshot);
 302            let end = range.end.to_offset(&snapshot);
 303            cursor.seek(&start, Bias::Right, &());
 304            if cursor.item().is_none() && start == *cursor.start() {
 305                cursor.prev(&());
 306            }
 307            let start_excerpt = cursor.item().expect("start offset out of bounds");
 308            let start_overshoot = start - cursor.start();
 309            let buffer_start =
 310                start_excerpt.range.start.to_offset(&start_excerpt.buffer) + start_overshoot;
 311
 312            cursor.seek(&end, Bias::Right, &());
 313            if cursor.item().is_none() && end == *cursor.start() {
 314                cursor.prev(&());
 315            }
 316            let end_excerpt = cursor.item().expect("end offset out of bounds");
 317            let end_overshoot = end - cursor.start();
 318            let buffer_end = end_excerpt.range.start.to_offset(&end_excerpt.buffer) + end_overshoot;
 319
 320            if start_excerpt.id == end_excerpt.id {
 321                buffer_edits
 322                    .entry(start_excerpt.buffer_id)
 323                    .or_insert(Vec::new())
 324                    .push((buffer_start..buffer_end, true));
 325            } else {
 326                let start_excerpt_range =
 327                    buffer_start..start_excerpt.range.end.to_offset(&start_excerpt.buffer);
 328                let end_excerpt_range =
 329                    end_excerpt.range.start.to_offset(&end_excerpt.buffer)..buffer_end;
 330                buffer_edits
 331                    .entry(start_excerpt.buffer_id)
 332                    .or_insert(Vec::new())
 333                    .push((start_excerpt_range, true));
 334                buffer_edits
 335                    .entry(end_excerpt.buffer_id)
 336                    .or_insert(Vec::new())
 337                    .push((end_excerpt_range, false));
 338
 339                cursor.seek(&start, Bias::Right, &());
 340                cursor.next(&());
 341                while let Some(excerpt) = cursor.item() {
 342                    if excerpt.id == end_excerpt.id {
 343                        break;
 344                    }
 345                    buffer_edits
 346                        .entry(excerpt.buffer_id)
 347                        .or_insert(Vec::new())
 348                        .push((excerpt.range.to_offset(&excerpt.buffer), false));
 349                    cursor.next(&());
 350                }
 351            }
 352        }
 353
 354        let new_text = new_text.into();
 355        for (buffer_id, mut edits) in buffer_edits {
 356            edits.sort_unstable_by_key(|(range, _)| range.start);
 357            self.buffers.borrow()[&buffer_id]
 358                .buffer
 359                .update(cx, |buffer, cx| {
 360                    let mut edits = edits.into_iter().peekable();
 361                    let mut insertions = Vec::new();
 362                    let mut deletions = Vec::new();
 363                    while let Some((mut range, mut is_insertion)) = edits.next() {
 364                        while let Some((next_range, next_is_insertion)) = edits.peek() {
 365                            if range.end >= next_range.start {
 366                                range.end = cmp::max(next_range.end, range.end);
 367                                is_insertion |= *next_is_insertion;
 368                                edits.next();
 369                            } else {
 370                                break;
 371                            }
 372                        }
 373
 374                        if is_insertion {
 375                            insertions.push(
 376                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 377                            );
 378                        } else if !range.is_empty() {
 379                            deletions.push(
 380                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 381                            );
 382                        }
 383                    }
 384
 385                    if autoindent {
 386                        buffer.edit_with_autoindent(deletions, "", cx);
 387                        buffer.edit_with_autoindent(insertions, new_text.clone(), cx);
 388                    } else {
 389                        buffer.edit(deletions, "", cx);
 390                        buffer.edit(insertions, new_text.clone(), cx);
 391                    }
 392                })
 393        }
 394    }
 395
 396    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 397        self.start_transaction_at(Instant::now(), cx)
 398    }
 399
 400    pub(crate) fn start_transaction_at(
 401        &mut self,
 402        now: Instant,
 403        cx: &mut ModelContext<Self>,
 404    ) -> Option<TransactionId> {
 405        if let Some(buffer) = self.as_singleton() {
 406            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 407        }
 408
 409        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 410            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 411        }
 412        self.history.start_transaction(now)
 413    }
 414
 415    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 416        self.end_transaction_at(Instant::now(), cx)
 417    }
 418
 419    pub(crate) fn end_transaction_at(
 420        &mut self,
 421        now: Instant,
 422        cx: &mut ModelContext<Self>,
 423    ) -> Option<TransactionId> {
 424        if let Some(buffer) = self.as_singleton() {
 425            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 426        }
 427
 428        let mut buffer_transactions = HashMap::default();
 429        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 430            if let Some(transaction_id) =
 431                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 432            {
 433                buffer_transactions.insert(buffer.id(), transaction_id);
 434            }
 435        }
 436
 437        if self.history.end_transaction(now, buffer_transactions) {
 438            let transaction_id = self.history.group().unwrap();
 439            Some(transaction_id)
 440        } else {
 441            None
 442        }
 443    }
 444
 445    pub fn finalize_last_transaction(&mut self, cx: &mut ModelContext<Self>) {
 446        self.history.finalize_last_transaction();
 447        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 448            buffer.update(cx, |buffer, _| {
 449                buffer.finalize_last_transaction();
 450            });
 451        }
 452    }
 453
 454    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T)
 455    where
 456        T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
 457    {
 458        self.history
 459            .push_transaction(buffer_transactions, Instant::now());
 460        self.history.finalize_last_transaction();
 461    }
 462
 463    pub fn set_active_selections(
 464        &mut self,
 465        selections: &[Selection<Anchor>],
 466        cx: &mut ModelContext<Self>,
 467    ) {
 468        let mut selections_by_buffer: HashMap<usize, Vec<Selection<text::Anchor>>> =
 469            Default::default();
 470        let snapshot = self.read(cx);
 471        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 472        for selection in selections {
 473            cursor.seek(&Some(&selection.start.excerpt_id), Bias::Left, &());
 474            while let Some(excerpt) = cursor.item() {
 475                if excerpt.id > selection.end.excerpt_id {
 476                    break;
 477                }
 478
 479                let mut start = excerpt.range.start.clone();
 480                let mut end = excerpt.range.end.clone();
 481                if excerpt.id == selection.start.excerpt_id {
 482                    start = selection.start.text_anchor.clone();
 483                }
 484                if excerpt.id == selection.end.excerpt_id {
 485                    end = selection.end.text_anchor.clone();
 486                }
 487                selections_by_buffer
 488                    .entry(excerpt.buffer_id)
 489                    .or_default()
 490                    .push(Selection {
 491                        id: selection.id,
 492                        start,
 493                        end,
 494                        reversed: selection.reversed,
 495                        goal: selection.goal,
 496                    });
 497
 498                cursor.next(&());
 499            }
 500        }
 501
 502        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 503            if !selections_by_buffer.contains_key(buffer_id) {
 504                buffer_state
 505                    .buffer
 506                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 507            }
 508        }
 509
 510        for (buffer_id, mut selections) in selections_by_buffer {
 511            self.buffers.borrow()[&buffer_id]
 512                .buffer
 513                .update(cx, |buffer, cx| {
 514                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer).unwrap());
 515                    let mut selections = selections.into_iter().peekable();
 516                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 517                        let mut selection = selections.next()?;
 518                        while let Some(next_selection) = selections.peek() {
 519                            if selection
 520                                .end
 521                                .cmp(&next_selection.start, buffer)
 522                                .unwrap()
 523                                .is_ge()
 524                            {
 525                                let next_selection = selections.next().unwrap();
 526                                if next_selection
 527                                    .end
 528                                    .cmp(&selection.end, buffer)
 529                                    .unwrap()
 530                                    .is_ge()
 531                                {
 532                                    selection.end = next_selection.end;
 533                                }
 534                            } else {
 535                                break;
 536                            }
 537                        }
 538                        Some(selection)
 539                    }));
 540                    buffer.set_active_selections(merged_selections, cx);
 541                });
 542        }
 543    }
 544
 545    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
 546        for buffer in self.buffers.borrow().values() {
 547            buffer
 548                .buffer
 549                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 550        }
 551    }
 552
 553    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 554        if let Some(buffer) = self.as_singleton() {
 555            return buffer.update(cx, |buffer, cx| buffer.undo(cx));
 556        }
 557
 558        while let Some(transaction) = self.history.pop_undo() {
 559            let mut undone = false;
 560            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 561                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 562                    undone |= buffer.update(cx, |buffer, cx| {
 563                        let undo_to = *buffer_transaction_id;
 564                        if let Some(entry) = buffer.peek_undo_stack() {
 565                            *buffer_transaction_id = entry.transaction_id();
 566                        }
 567                        buffer.undo_to_transaction(undo_to, cx)
 568                    });
 569                }
 570            }
 571
 572            if undone {
 573                return Some(transaction.id);
 574            }
 575        }
 576
 577        None
 578    }
 579
 580    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 581        if let Some(buffer) = self.as_singleton() {
 582            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
 583        }
 584
 585        while let Some(transaction) = self.history.pop_redo() {
 586            let mut redone = false;
 587            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 588                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 589                    redone |= buffer.update(cx, |buffer, cx| {
 590                        let redo_to = *buffer_transaction_id;
 591                        if let Some(entry) = buffer.peek_redo_stack() {
 592                            *buffer_transaction_id = entry.transaction_id();
 593                        }
 594                        buffer.redo_to_transaction(redo_to, cx)
 595                    });
 596                }
 597            }
 598
 599            if redone {
 600                return Some(transaction.id);
 601            }
 602        }
 603
 604        None
 605    }
 606
 607    pub fn push_excerpts<O>(
 608        &mut self,
 609        buffer: ModelHandle<Buffer>,
 610        ranges: impl IntoIterator<Item = Range<O>>,
 611        cx: &mut ModelContext<Self>,
 612    ) -> Vec<ExcerptId>
 613    where
 614        O: text::ToOffset,
 615    {
 616        self.insert_excerpts_after(&ExcerptId::max(), buffer, ranges, cx)
 617    }
 618
 619    pub fn push_excerpts_with_context_lines<O>(
 620        &mut self,
 621        buffer: ModelHandle<Buffer>,
 622        ranges: Vec<Range<O>>,
 623        context_line_count: u32,
 624        cx: &mut ModelContext<Self>,
 625    ) -> Vec<Range<Anchor>>
 626    where
 627        O: text::ToPoint + text::ToOffset,
 628    {
 629        let buffer_id = buffer.id();
 630        let buffer_snapshot = buffer.read(cx).snapshot();
 631        let max_point = buffer_snapshot.max_point();
 632
 633        let mut range_counts = Vec::new();
 634        let mut excerpt_ranges = Vec::new();
 635        let mut range_iter = ranges
 636            .iter()
 637            .map(|range| {
 638                range.start.to_point(&buffer_snapshot)..range.end.to_point(&buffer_snapshot)
 639            })
 640            .peekable();
 641        while let Some(range) = range_iter.next() {
 642            let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
 643            let mut excerpt_end =
 644                Point::new(range.end.row + 1 + context_line_count, 0).min(max_point);
 645            let mut ranges_in_excerpt = 1;
 646
 647            while let Some(next_range) = range_iter.peek() {
 648                if next_range.start.row <= excerpt_end.row + context_line_count {
 649                    excerpt_end =
 650                        Point::new(next_range.end.row + 1 + context_line_count, 0).min(max_point);
 651                    ranges_in_excerpt += 1;
 652                    range_iter.next();
 653                } else {
 654                    break;
 655                }
 656            }
 657
 658            excerpt_ranges.push(excerpt_start..excerpt_end);
 659            range_counts.push(ranges_in_excerpt);
 660        }
 661
 662        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
 663
 664        let mut anchor_ranges = Vec::new();
 665        let mut ranges = ranges.into_iter();
 666        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
 667            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
 668                let start = Anchor {
 669                    buffer_id,
 670                    excerpt_id: excerpt_id.clone(),
 671                    text_anchor: buffer_snapshot.anchor_after(range.start),
 672                };
 673                let end = Anchor {
 674                    buffer_id,
 675                    excerpt_id: excerpt_id.clone(),
 676                    text_anchor: buffer_snapshot.anchor_after(range.end),
 677                };
 678                start..end
 679            }))
 680        }
 681        anchor_ranges
 682    }
 683
 684    pub fn insert_excerpts_after<O>(
 685        &mut self,
 686        prev_excerpt_id: &ExcerptId,
 687        buffer: ModelHandle<Buffer>,
 688        ranges: impl IntoIterator<Item = Range<O>>,
 689        cx: &mut ModelContext<Self>,
 690    ) -> Vec<ExcerptId>
 691    where
 692        O: text::ToOffset,
 693    {
 694        assert_eq!(self.history.transaction_depth, 0);
 695        self.sync(cx);
 696
 697        let buffer_id = buffer.id();
 698        let buffer_snapshot = buffer.read(cx).snapshot();
 699
 700        let mut buffers = self.buffers.borrow_mut();
 701        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
 702            last_version: buffer_snapshot.version().clone(),
 703            last_parse_count: buffer_snapshot.parse_count(),
 704            last_selections_update_count: buffer_snapshot.selections_update_count(),
 705            last_diagnostics_update_count: buffer_snapshot.diagnostics_update_count(),
 706            last_file_update_count: buffer_snapshot.file_update_count(),
 707            excerpts: Default::default(),
 708            _subscriptions: [
 709                cx.observe(&buffer, |_, _, cx| cx.notify()),
 710                cx.subscribe(&buffer, Self::on_buffer_event),
 711            ],
 712            buffer,
 713        });
 714
 715        let mut snapshot = self.snapshot.borrow_mut();
 716        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 717        let mut new_excerpts = cursor.slice(&Some(prev_excerpt_id), Bias::Right, &());
 718
 719        let mut prev_id = ExcerptId::min();
 720        let edit_start = new_excerpts.summary().text.bytes;
 721        new_excerpts.update_last(
 722            |excerpt| {
 723                excerpt.has_trailing_newline = true;
 724                prev_id = excerpt.id.clone();
 725            },
 726            &(),
 727        );
 728
 729        let mut next_id = ExcerptId::max();
 730        if let Some(next_excerpt) = cursor.item() {
 731            next_id = next_excerpt.id.clone();
 732        }
 733
 734        let mut ids = Vec::new();
 735        let mut ranges = ranges.into_iter().peekable();
 736        while let Some(range) = ranges.next() {
 737            let id = ExcerptId::between(&prev_id, &next_id);
 738            if let Err(ix) = buffer_state.excerpts.binary_search(&id) {
 739                buffer_state.excerpts.insert(ix, id.clone());
 740            }
 741            let range = buffer_snapshot.anchor_before(&range.start)
 742                ..buffer_snapshot.anchor_after(&range.end);
 743            let excerpt = Excerpt::new(
 744                id.clone(),
 745                buffer_id,
 746                buffer_snapshot.clone(),
 747                range,
 748                ranges.peek().is_some() || cursor.item().is_some(),
 749            );
 750            new_excerpts.push(excerpt, &());
 751            prev_id = id.clone();
 752            ids.push(id);
 753        }
 754
 755        let edit_end = new_excerpts.summary().text.bytes;
 756
 757        let suffix = cursor.suffix(&());
 758        let changed_trailing_excerpt = suffix.is_empty();
 759        new_excerpts.push_tree(suffix, &());
 760        drop(cursor);
 761        snapshot.excerpts = new_excerpts;
 762        if changed_trailing_excerpt {
 763            snapshot.trailing_excerpt_update_count += 1;
 764        }
 765
 766        self.subscriptions.publish_mut([Edit {
 767            old: edit_start..edit_start,
 768            new: edit_start..edit_end,
 769        }]);
 770
 771        cx.notify();
 772        ids
 773    }
 774
 775    pub fn excerpt_ids_for_buffer(&self, buffer: &ModelHandle<Buffer>) -> Vec<ExcerptId> {
 776        self.buffers
 777            .borrow()
 778            .get(&buffer.id())
 779            .map_or(Vec::new(), |state| state.excerpts.clone())
 780    }
 781
 782    pub fn excerpt_containing(
 783        &self,
 784        position: impl ToOffset,
 785        cx: &AppContext,
 786    ) -> Option<(ModelHandle<Buffer>, Range<text::Anchor>)> {
 787        let snapshot = self.read(cx);
 788        let position = position.to_offset(&snapshot);
 789
 790        let mut cursor = snapshot.excerpts.cursor::<usize>();
 791        cursor.seek(&position, Bias::Right, &());
 792        cursor.item().map(|excerpt| {
 793            (
 794                self.buffers
 795                    .borrow()
 796                    .get(&excerpt.buffer_id)
 797                    .unwrap()
 798                    .buffer
 799                    .clone(),
 800                excerpt.range.clone(),
 801            )
 802        })
 803    }
 804
 805    pub fn range_to_buffer_ranges<'a, T: ToOffset>(
 806        &'a self,
 807        range: Range<T>,
 808        cx: &AppContext,
 809    ) -> Vec<(ModelHandle<Buffer>, Range<usize>)> {
 810        let snapshot = self.read(cx);
 811        let start = range.start.to_offset(&snapshot);
 812        let end = range.end.to_offset(&snapshot);
 813
 814        let mut result = Vec::new();
 815        let mut cursor = snapshot.excerpts.cursor::<usize>();
 816        cursor.seek(&start, Bias::Right, &());
 817        while let Some(excerpt) = cursor.item() {
 818            if *cursor.start() > end {
 819                break;
 820            }
 821
 822            let mut end_before_newline = cursor.end(&());
 823            if excerpt.has_trailing_newline {
 824                end_before_newline -= 1;
 825            }
 826            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
 827            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
 828            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
 829            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
 830            result.push((buffer, start..end));
 831            cursor.next(&());
 832        }
 833
 834        result
 835    }
 836
 837    pub fn remove_excerpts<'a>(
 838        &mut self,
 839        excerpt_ids: impl IntoIterator<Item = &'a ExcerptId>,
 840        cx: &mut ModelContext<Self>,
 841    ) {
 842        let mut buffers = self.buffers.borrow_mut();
 843        let mut snapshot = self.snapshot.borrow_mut();
 844        let mut new_excerpts = SumTree::new();
 845        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
 846        let mut edits = Vec::new();
 847        let mut excerpt_ids = excerpt_ids.into_iter().peekable();
 848
 849        while let Some(mut excerpt_id) = excerpt_ids.next() {
 850            // Seek to the next excerpt to remove, preserving any preceding excerpts.
 851            new_excerpts.push_tree(cursor.slice(&Some(excerpt_id), Bias::Left, &()), &());
 852            if let Some(mut excerpt) = cursor.item() {
 853                if excerpt.id != *excerpt_id {
 854                    continue;
 855                }
 856                let mut old_start = cursor.start().1;
 857
 858                // Skip over the removed excerpt.
 859                loop {
 860                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
 861                        buffer_state.excerpts.retain(|id| id != excerpt_id);
 862                        if buffer_state.excerpts.is_empty() {
 863                            buffers.remove(&excerpt.buffer_id);
 864                        }
 865                    }
 866                    cursor.next(&());
 867
 868                    // Skip over any subsequent excerpts that are also removed.
 869                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
 870                        if let Some(next_excerpt) = cursor.item() {
 871                            if next_excerpt.id == *next_excerpt_id {
 872                                excerpt = next_excerpt;
 873                                excerpt_id = excerpt_ids.next().unwrap();
 874                                continue;
 875                            }
 876                        }
 877                    }
 878
 879                    break;
 880                }
 881
 882                // When removing the last excerpt, remove the trailing newline from
 883                // the previous excerpt.
 884                if cursor.item().is_none() && old_start > 0 {
 885                    old_start -= 1;
 886                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
 887                }
 888
 889                // Push an edit for the removal of this run of excerpts.
 890                let old_end = cursor.start().1;
 891                let new_start = new_excerpts.summary().text.bytes;
 892                edits.push(Edit {
 893                    old: old_start..old_end,
 894                    new: new_start..new_start,
 895                });
 896            }
 897        }
 898        let suffix = cursor.suffix(&());
 899        let changed_trailing_excerpt = suffix.is_empty();
 900        new_excerpts.push_tree(suffix, &());
 901        drop(cursor);
 902        snapshot.excerpts = new_excerpts;
 903        if changed_trailing_excerpt {
 904            snapshot.trailing_excerpt_update_count += 1;
 905        }
 906
 907        self.subscriptions.publish_mut(edits);
 908        cx.notify();
 909    }
 910
 911    pub fn text_anchor_for_position<'a, T: ToOffset>(
 912        &'a self,
 913        position: T,
 914        cx: &AppContext,
 915    ) -> (ModelHandle<Buffer>, language::Anchor) {
 916        let snapshot = self.read(cx);
 917        let anchor = snapshot.anchor_before(position);
 918        (
 919            self.buffers.borrow()[&anchor.buffer_id].buffer.clone(),
 920            anchor.text_anchor,
 921        )
 922    }
 923
 924    fn on_buffer_event(
 925        &mut self,
 926        _: ModelHandle<Buffer>,
 927        event: &Event,
 928        cx: &mut ModelContext<Self>,
 929    ) {
 930        cx.emit(event.clone());
 931    }
 932
 933    pub fn format(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
 934        let mut format_tasks = Vec::new();
 935        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 936            format_tasks.push(buffer.update(cx, |buffer, cx| buffer.format(cx)));
 937        }
 938
 939        cx.spawn(|_, _| async move {
 940            for format in format_tasks {
 941                format.await?;
 942            }
 943            Ok(())
 944        })
 945    }
 946
 947    pub fn save(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
 948        let mut save_tasks = Vec::new();
 949        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 950            save_tasks.push(buffer.update(cx, |buffer, cx| buffer.save(cx)));
 951        }
 952
 953        cx.spawn(|_, _| async move {
 954            for save in save_tasks {
 955                save.await?;
 956            }
 957            Ok(())
 958        })
 959    }
 960
 961    pub fn is_completion_trigger<T>(&self, position: T, text: &str, cx: &AppContext) -> bool
 962    where
 963        T: ToOffset,
 964    {
 965        let mut chars = text.chars();
 966        let char = if let Some(char) = chars.next() {
 967            char
 968        } else {
 969            return false;
 970        };
 971        if chars.next().is_some() {
 972            return false;
 973        }
 974
 975        if char.is_alphanumeric() || char == '_' {
 976            return true;
 977        }
 978
 979        let snapshot = self.snapshot(cx);
 980        let anchor = snapshot.anchor_before(position);
 981        let buffer = self.buffers.borrow()[&anchor.buffer_id].buffer.clone();
 982        buffer
 983            .read(cx)
 984            .completion_triggers()
 985            .iter()
 986            .any(|string| string == text)
 987    }
 988
 989    pub fn language<'a>(&self, cx: &'a AppContext) -> Option<&'a Arc<Language>> {
 990        self.buffers
 991            .borrow()
 992            .values()
 993            .next()
 994            .and_then(|state| state.buffer.read(cx).language())
 995    }
 996
 997    pub fn file<'a>(&self, cx: &'a AppContext) -> Option<&'a dyn File> {
 998        self.as_singleton()?.read(cx).file()
 999    }
1000
1001    pub fn title(&self, cx: &AppContext) -> String {
1002        if let Some(title) = self.title.clone() {
1003            title
1004        } else if let Some(file) = self.file(cx) {
1005            file.file_name(cx).to_string_lossy().into()
1006        } else {
1007            "untitled".into()
1008        }
1009    }
1010
1011    #[cfg(test)]
1012    pub fn is_parsing(&self, cx: &AppContext) -> bool {
1013        self.as_singleton().unwrap().read(cx).is_parsing()
1014    }
1015
1016    fn sync(&self, cx: &AppContext) {
1017        let mut snapshot = self.snapshot.borrow_mut();
1018        let mut excerpts_to_edit = Vec::new();
1019        let mut reparsed = false;
1020        let mut diagnostics_updated = false;
1021        let mut is_dirty = false;
1022        let mut has_conflict = false;
1023        let mut buffers = self.buffers.borrow_mut();
1024        for buffer_state in buffers.values_mut() {
1025            let buffer = buffer_state.buffer.read(cx);
1026            let version = buffer.version();
1027            let parse_count = buffer.parse_count();
1028            let selections_update_count = buffer.selections_update_count();
1029            let diagnostics_update_count = buffer.diagnostics_update_count();
1030            let file_update_count = buffer.file_update_count();
1031
1032            let buffer_edited = version.changed_since(&buffer_state.last_version);
1033            let buffer_reparsed = parse_count > buffer_state.last_parse_count;
1034            let buffer_selections_updated =
1035                selections_update_count > buffer_state.last_selections_update_count;
1036            let buffer_diagnostics_updated =
1037                diagnostics_update_count > buffer_state.last_diagnostics_update_count;
1038            let buffer_file_updated = file_update_count > buffer_state.last_file_update_count;
1039            if buffer_edited
1040                || buffer_reparsed
1041                || buffer_selections_updated
1042                || buffer_diagnostics_updated
1043                || buffer_file_updated
1044            {
1045                buffer_state.last_version = version;
1046                buffer_state.last_parse_count = parse_count;
1047                buffer_state.last_selections_update_count = selections_update_count;
1048                buffer_state.last_diagnostics_update_count = diagnostics_update_count;
1049                buffer_state.last_file_update_count = file_update_count;
1050                excerpts_to_edit.extend(
1051                    buffer_state
1052                        .excerpts
1053                        .iter()
1054                        .map(|excerpt_id| (excerpt_id, buffer_state.buffer.clone(), buffer_edited)),
1055                );
1056            }
1057
1058            reparsed |= buffer_reparsed;
1059            diagnostics_updated |= buffer_diagnostics_updated;
1060            is_dirty |= buffer.is_dirty();
1061            has_conflict |= buffer.has_conflict();
1062        }
1063        if reparsed {
1064            snapshot.parse_count += 1;
1065        }
1066        if diagnostics_updated {
1067            snapshot.diagnostics_update_count += 1;
1068        }
1069        snapshot.is_dirty = is_dirty;
1070        snapshot.has_conflict = has_conflict;
1071
1072        excerpts_to_edit.sort_unstable_by_key(|(excerpt_id, _, _)| *excerpt_id);
1073
1074        let mut edits = Vec::new();
1075        let mut new_excerpts = SumTree::new();
1076        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
1077
1078        for (id, buffer, buffer_edited) in excerpts_to_edit {
1079            new_excerpts.push_tree(cursor.slice(&Some(id), Bias::Left, &()), &());
1080            let old_excerpt = cursor.item().unwrap();
1081            let buffer_id = buffer.id();
1082            let buffer = buffer.read(cx);
1083
1084            let mut new_excerpt;
1085            if buffer_edited {
1086                edits.extend(
1087                    buffer
1088                        .edits_since_in_range::<usize>(
1089                            old_excerpt.buffer.version(),
1090                            old_excerpt.range.clone(),
1091                        )
1092                        .map(|mut edit| {
1093                            let excerpt_old_start = cursor.start().1;
1094                            let excerpt_new_start = new_excerpts.summary().text.bytes;
1095                            edit.old.start += excerpt_old_start;
1096                            edit.old.end += excerpt_old_start;
1097                            edit.new.start += excerpt_new_start;
1098                            edit.new.end += excerpt_new_start;
1099                            edit
1100                        }),
1101                );
1102
1103                new_excerpt = Excerpt::new(
1104                    id.clone(),
1105                    buffer_id,
1106                    buffer.snapshot(),
1107                    old_excerpt.range.clone(),
1108                    old_excerpt.has_trailing_newline,
1109                );
1110            } else {
1111                new_excerpt = old_excerpt.clone();
1112                new_excerpt.buffer = buffer.snapshot();
1113            }
1114
1115            new_excerpts.push(new_excerpt, &());
1116            cursor.next(&());
1117        }
1118        new_excerpts.push_tree(cursor.suffix(&()), &());
1119
1120        drop(cursor);
1121        snapshot.excerpts = new_excerpts;
1122
1123        self.subscriptions.publish(edits);
1124    }
1125}
1126
1127#[cfg(any(test, feature = "test-support"))]
1128impl MultiBuffer {
1129    pub fn randomly_edit(
1130        &mut self,
1131        rng: &mut impl rand::Rng,
1132        count: usize,
1133        cx: &mut ModelContext<Self>,
1134    ) {
1135        use text::RandomCharIter;
1136
1137        let snapshot = self.read(cx);
1138        let mut old_ranges: Vec<Range<usize>> = Vec::new();
1139        for _ in 0..count {
1140            let last_end = old_ranges.last().map_or(0, |last_range| last_range.end + 1);
1141            if last_end > snapshot.len() {
1142                break;
1143            }
1144            let end_ix = snapshot.clip_offset(rng.gen_range(0..=last_end), Bias::Right);
1145            let start_ix = snapshot.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1146            old_ranges.push(start_ix..end_ix);
1147        }
1148        let new_text_len = rng.gen_range(0..10);
1149        let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1150        log::info!("mutating multi-buffer at {:?}: {:?}", old_ranges, new_text);
1151        drop(snapshot);
1152
1153        self.edit(old_ranges.iter().cloned(), new_text.as_str(), cx);
1154    }
1155
1156    pub fn randomly_edit_excerpts(
1157        &mut self,
1158        rng: &mut impl rand::Rng,
1159        mutation_count: usize,
1160        cx: &mut ModelContext<Self>,
1161    ) {
1162        use rand::prelude::*;
1163        use std::env;
1164        use text::RandomCharIter;
1165
1166        let max_excerpts = env::var("MAX_EXCERPTS")
1167            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
1168            .unwrap_or(5);
1169
1170        let mut buffers = Vec::new();
1171        for _ in 0..mutation_count {
1172            let excerpt_ids = self
1173                .buffers
1174                .borrow()
1175                .values()
1176                .flat_map(|b| &b.excerpts)
1177                .cloned()
1178                .collect::<Vec<_>>();
1179            if excerpt_ids.len() == 0 || (rng.gen() && excerpt_ids.len() < max_excerpts) {
1180                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
1181                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
1182                    buffers.push(cx.add_model(|cx| Buffer::new(0, text, cx)));
1183                    let buffer = buffers.last().unwrap();
1184                    log::info!(
1185                        "Creating new buffer {} with text: {:?}",
1186                        buffer.id(),
1187                        buffer.read(cx).text()
1188                    );
1189                    buffers.last().unwrap().clone()
1190                } else {
1191                    self.buffers
1192                        .borrow()
1193                        .values()
1194                        .choose(rng)
1195                        .unwrap()
1196                        .buffer
1197                        .clone()
1198                };
1199
1200                let buffer = buffer_handle.read(cx);
1201                let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
1202                let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1203                log::info!(
1204                    "Inserting excerpt from buffer {} and range {:?}: {:?}",
1205                    buffer_handle.id(),
1206                    start_ix..end_ix,
1207                    &buffer.text()[start_ix..end_ix]
1208                );
1209
1210                let excerpt_id = self.push_excerpts(buffer_handle.clone(), [start_ix..end_ix], cx);
1211                log::info!("Inserted with id: {:?}", excerpt_id);
1212            } else {
1213                let remove_count = rng.gen_range(1..=excerpt_ids.len());
1214                let mut excerpts_to_remove = excerpt_ids
1215                    .choose_multiple(rng, remove_count)
1216                    .cloned()
1217                    .collect::<Vec<_>>();
1218                excerpts_to_remove.sort();
1219                log::info!("Removing excerpts {:?}", excerpts_to_remove);
1220                self.remove_excerpts(&excerpts_to_remove, cx);
1221            }
1222        }
1223    }
1224
1225    pub fn randomly_mutate(
1226        &mut self,
1227        rng: &mut impl rand::Rng,
1228        mutation_count: usize,
1229        cx: &mut ModelContext<Self>,
1230    ) {
1231        if rng.gen_bool(0.7) || self.singleton {
1232            self.randomly_edit(rng, mutation_count, cx);
1233        } else {
1234            self.randomly_edit_excerpts(rng, mutation_count, cx);
1235        }
1236    }
1237}
1238
1239impl Entity for MultiBuffer {
1240    type Event = language::Event;
1241}
1242
1243impl MultiBufferSnapshot {
1244    pub fn text(&self) -> String {
1245        self.chunks(0..self.len(), false)
1246            .map(|chunk| chunk.text)
1247            .collect()
1248    }
1249
1250    pub fn reversed_chars_at<'a, T: ToOffset>(
1251        &'a self,
1252        position: T,
1253    ) -> impl Iterator<Item = char> + 'a {
1254        let mut offset = position.to_offset(self);
1255        let mut cursor = self.excerpts.cursor::<usize>();
1256        cursor.seek(&offset, Bias::Left, &());
1257        let mut excerpt_chunks = cursor.item().map(|excerpt| {
1258            let end_before_footer = cursor.start() + excerpt.text_summary.bytes;
1259            let start = excerpt.range.start.to_offset(&excerpt.buffer);
1260            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
1261            excerpt.buffer.reversed_chunks_in_range(start..end)
1262        });
1263        iter::from_fn(move || {
1264            if offset == *cursor.start() {
1265                cursor.prev(&());
1266                let excerpt = cursor.item()?;
1267                excerpt_chunks = Some(
1268                    excerpt
1269                        .buffer
1270                        .reversed_chunks_in_range(excerpt.range.clone()),
1271                );
1272            }
1273
1274            let excerpt = cursor.item().unwrap();
1275            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
1276                offset -= 1;
1277                Some("\n")
1278            } else {
1279                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
1280                offset -= chunk.len();
1281                Some(chunk)
1282            }
1283        })
1284        .flat_map(|c| c.chars().rev())
1285    }
1286
1287    pub fn chars_at<'a, T: ToOffset>(&'a self, position: T) -> impl Iterator<Item = char> + 'a {
1288        let offset = position.to_offset(self);
1289        self.text_for_range(offset..self.len())
1290            .flat_map(|chunk| chunk.chars())
1291    }
1292
1293    pub fn text_for_range<'a, T: ToOffset>(
1294        &'a self,
1295        range: Range<T>,
1296    ) -> impl Iterator<Item = &'a str> {
1297        self.chunks(range, false).map(|chunk| chunk.text)
1298    }
1299
1300    pub fn is_line_blank(&self, row: u32) -> bool {
1301        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1302            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1303    }
1304
1305    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1306    where
1307        T: ToOffset,
1308    {
1309        let position = position.to_offset(self);
1310        position == self.clip_offset(position, Bias::Left)
1311            && self
1312                .bytes_in_range(position..self.len())
1313                .flatten()
1314                .copied()
1315                .take(needle.len())
1316                .eq(needle.bytes())
1317    }
1318
1319    pub fn surrounding_word<T: ToOffset>(&self, start: T) -> (Range<usize>, Option<CharKind>) {
1320        let mut start = start.to_offset(self);
1321        let mut end = start;
1322        let mut next_chars = self.chars_at(start).peekable();
1323        let mut prev_chars = self.reversed_chars_at(start).peekable();
1324        let word_kind = cmp::max(
1325            prev_chars.peek().copied().map(char_kind),
1326            next_chars.peek().copied().map(char_kind),
1327        );
1328
1329        for ch in prev_chars {
1330            if Some(char_kind(ch)) == word_kind {
1331                start -= ch.len_utf8();
1332            } else {
1333                break;
1334            }
1335        }
1336
1337        for ch in next_chars {
1338            if Some(char_kind(ch)) == word_kind {
1339                end += ch.len_utf8();
1340            } else {
1341                break;
1342            }
1343        }
1344
1345        (start..end, word_kind)
1346    }
1347
1348    fn as_singleton(&self) -> Option<&Excerpt> {
1349        if self.singleton {
1350            self.excerpts.iter().next()
1351        } else {
1352            None
1353        }
1354    }
1355
1356    pub fn len(&self) -> usize {
1357        self.excerpts.summary().text.bytes
1358    }
1359
1360    pub fn max_buffer_row(&self) -> u32 {
1361        self.excerpts.summary().max_buffer_row
1362    }
1363
1364    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
1365        if let Some(excerpt) = self.as_singleton() {
1366            return excerpt.buffer.clip_offset(offset, bias);
1367        }
1368
1369        let mut cursor = self.excerpts.cursor::<usize>();
1370        cursor.seek(&offset, Bias::Right, &());
1371        let overshoot = if let Some(excerpt) = cursor.item() {
1372            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1373            let buffer_offset = excerpt
1374                .buffer
1375                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
1376            buffer_offset.saturating_sub(excerpt_start)
1377        } else {
1378            0
1379        };
1380        cursor.start() + overshoot
1381    }
1382
1383    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1384        if let Some(excerpt) = self.as_singleton() {
1385            return excerpt.buffer.clip_point(point, bias);
1386        }
1387
1388        let mut cursor = self.excerpts.cursor::<Point>();
1389        cursor.seek(&point, Bias::Right, &());
1390        let overshoot = if let Some(excerpt) = cursor.item() {
1391            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1392            let buffer_point = excerpt
1393                .buffer
1394                .clip_point(excerpt_start + (point - cursor.start()), bias);
1395            buffer_point.saturating_sub(excerpt_start)
1396        } else {
1397            Point::zero()
1398        };
1399        *cursor.start() + overshoot
1400    }
1401
1402    pub fn clip_point_utf16(&self, point: PointUtf16, bias: Bias) -> PointUtf16 {
1403        if let Some(excerpt) = self.as_singleton() {
1404            return excerpt.buffer.clip_point_utf16(point, bias);
1405        }
1406
1407        let mut cursor = self.excerpts.cursor::<PointUtf16>();
1408        cursor.seek(&point, Bias::Right, &());
1409        let overshoot = if let Some(excerpt) = cursor.item() {
1410            let excerpt_start = excerpt
1411                .buffer
1412                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1413            let buffer_point = excerpt
1414                .buffer
1415                .clip_point_utf16(excerpt_start + (point - cursor.start()), bias);
1416            buffer_point.saturating_sub(excerpt_start)
1417        } else {
1418            PointUtf16::zero()
1419        };
1420        *cursor.start() + overshoot
1421    }
1422
1423    pub fn bytes_in_range<'a, T: ToOffset>(&'a self, range: Range<T>) -> MultiBufferBytes<'a> {
1424        let range = range.start.to_offset(self)..range.end.to_offset(self);
1425        let mut excerpts = self.excerpts.cursor::<usize>();
1426        excerpts.seek(&range.start, Bias::Right, &());
1427
1428        let mut chunk = &[][..];
1429        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
1430            let mut excerpt_bytes = excerpt
1431                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
1432            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
1433            Some(excerpt_bytes)
1434        } else {
1435            None
1436        };
1437
1438        MultiBufferBytes {
1439            range,
1440            excerpts,
1441            excerpt_bytes,
1442            chunk,
1443        }
1444    }
1445
1446    pub fn buffer_rows<'a>(&'a self, start_row: u32) -> MultiBufferRows<'a> {
1447        let mut result = MultiBufferRows {
1448            buffer_row_range: 0..0,
1449            excerpts: self.excerpts.cursor(),
1450        };
1451        result.seek(start_row);
1452        result
1453    }
1454
1455    pub fn chunks<'a, T: ToOffset>(
1456        &'a self,
1457        range: Range<T>,
1458        language_aware: bool,
1459    ) -> MultiBufferChunks<'a> {
1460        let range = range.start.to_offset(self)..range.end.to_offset(self);
1461        let mut chunks = MultiBufferChunks {
1462            range: range.clone(),
1463            excerpts: self.excerpts.cursor(),
1464            excerpt_chunks: None,
1465            language_aware,
1466        };
1467        chunks.seek(range.start);
1468        chunks
1469    }
1470
1471    pub fn offset_to_point(&self, offset: usize) -> Point {
1472        if let Some(excerpt) = self.as_singleton() {
1473            return excerpt.buffer.offset_to_point(offset);
1474        }
1475
1476        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1477        cursor.seek(&offset, Bias::Right, &());
1478        if let Some(excerpt) = cursor.item() {
1479            let (start_offset, start_point) = cursor.start();
1480            let overshoot = offset - start_offset;
1481            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1482            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1483            let buffer_point = excerpt
1484                .buffer
1485                .offset_to_point(excerpt_start_offset + overshoot);
1486            *start_point + (buffer_point - excerpt_start_point)
1487        } else {
1488            self.excerpts.summary().text.lines
1489        }
1490    }
1491
1492    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
1493        if let Some(excerpt) = self.as_singleton() {
1494            return excerpt.buffer.offset_to_point_utf16(offset);
1495        }
1496
1497        let mut cursor = self.excerpts.cursor::<(usize, PointUtf16)>();
1498        cursor.seek(&offset, Bias::Right, &());
1499        if let Some(excerpt) = cursor.item() {
1500            let (start_offset, start_point) = cursor.start();
1501            let overshoot = offset - start_offset;
1502            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1503            let excerpt_start_point = excerpt.range.start.to_point_utf16(&excerpt.buffer);
1504            let buffer_point = excerpt
1505                .buffer
1506                .offset_to_point_utf16(excerpt_start_offset + overshoot);
1507            *start_point + (buffer_point - excerpt_start_point)
1508        } else {
1509            self.excerpts.summary().text.lines_utf16
1510        }
1511    }
1512
1513    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
1514        if let Some(excerpt) = self.as_singleton() {
1515            return excerpt.buffer.point_to_point_utf16(point);
1516        }
1517
1518        let mut cursor = self.excerpts.cursor::<(Point, PointUtf16)>();
1519        cursor.seek(&point, Bias::Right, &());
1520        if let Some(excerpt) = cursor.item() {
1521            let (start_offset, start_point) = cursor.start();
1522            let overshoot = point - start_offset;
1523            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1524            let excerpt_start_point_utf16 = excerpt.range.start.to_point_utf16(&excerpt.buffer);
1525            let buffer_point = excerpt
1526                .buffer
1527                .point_to_point_utf16(excerpt_start_point + overshoot);
1528            *start_point + (buffer_point - excerpt_start_point_utf16)
1529        } else {
1530            self.excerpts.summary().text.lines_utf16
1531        }
1532    }
1533
1534    pub fn point_to_offset(&self, point: Point) -> usize {
1535        if let Some(excerpt) = self.as_singleton() {
1536            return excerpt.buffer.point_to_offset(point);
1537        }
1538
1539        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
1540        cursor.seek(&point, Bias::Right, &());
1541        if let Some(excerpt) = cursor.item() {
1542            let (start_point, start_offset) = cursor.start();
1543            let overshoot = point - start_point;
1544            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1545            let excerpt_start_point = excerpt.range.start.to_point(&excerpt.buffer);
1546            let buffer_offset = excerpt
1547                .buffer
1548                .point_to_offset(excerpt_start_point + overshoot);
1549            *start_offset + buffer_offset - excerpt_start_offset
1550        } else {
1551            self.excerpts.summary().text.bytes
1552        }
1553    }
1554
1555    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
1556        if let Some(excerpt) = self.as_singleton() {
1557            return excerpt.buffer.point_utf16_to_offset(point);
1558        }
1559
1560        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
1561        cursor.seek(&point, Bias::Right, &());
1562        if let Some(excerpt) = cursor.item() {
1563            let (start_point, start_offset) = cursor.start();
1564            let overshoot = point - start_point;
1565            let excerpt_start_offset = excerpt.range.start.to_offset(&excerpt.buffer);
1566            let excerpt_start_point = excerpt
1567                .buffer
1568                .offset_to_point_utf16(excerpt.range.start.to_offset(&excerpt.buffer));
1569            let buffer_offset = excerpt
1570                .buffer
1571                .point_utf16_to_offset(excerpt_start_point + overshoot);
1572            *start_offset + (buffer_offset - excerpt_start_offset)
1573        } else {
1574            self.excerpts.summary().text.bytes
1575        }
1576    }
1577
1578    pub fn indent_column_for_line(&self, row: u32) -> u32 {
1579        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
1580            buffer
1581                .indent_column_for_line(range.start.row)
1582                .min(range.end.column)
1583                .saturating_sub(range.start.column)
1584        } else {
1585            0
1586        }
1587    }
1588
1589    pub fn line_len(&self, row: u32) -> u32 {
1590        if let Some((_, range)) = self.buffer_line_for_row(row) {
1591            range.end.column - range.start.column
1592        } else {
1593            0
1594        }
1595    }
1596
1597    fn buffer_line_for_row(&self, row: u32) -> Option<(&BufferSnapshot, Range<Point>)> {
1598        let mut cursor = self.excerpts.cursor::<Point>();
1599        cursor.seek(&Point::new(row, 0), Bias::Right, &());
1600        if let Some(excerpt) = cursor.item() {
1601            let overshoot = row - cursor.start().row;
1602            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer);
1603            let excerpt_end = excerpt.range.end.to_point(&excerpt.buffer);
1604            let buffer_row = excerpt_start.row + overshoot;
1605            let line_start = Point::new(buffer_row, 0);
1606            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
1607            return Some((
1608                &excerpt.buffer,
1609                line_start.max(excerpt_start)..line_end.min(excerpt_end),
1610            ));
1611        }
1612        None
1613    }
1614
1615    pub fn max_point(&self) -> Point {
1616        self.text_summary().lines
1617    }
1618
1619    pub fn text_summary(&self) -> TextSummary {
1620        self.excerpts.summary().text
1621    }
1622
1623    pub fn text_summary_for_range<'a, D, O>(&'a self, range: Range<O>) -> D
1624    where
1625        D: TextDimension,
1626        O: ToOffset,
1627    {
1628        let mut summary = D::default();
1629        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
1630        let mut cursor = self.excerpts.cursor::<usize>();
1631        cursor.seek(&range.start, Bias::Right, &());
1632        if let Some(excerpt) = cursor.item() {
1633            let mut end_before_newline = cursor.end(&());
1634            if excerpt.has_trailing_newline {
1635                end_before_newline -= 1;
1636            }
1637
1638            let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1639            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
1640            let end_in_excerpt =
1641                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
1642            summary.add_assign(
1643                &excerpt
1644                    .buffer
1645                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
1646            );
1647
1648            if range.end > end_before_newline {
1649                summary.add_assign(&D::from_text_summary(&TextSummary {
1650                    bytes: 1,
1651                    lines: Point::new(1 as u32, 0),
1652                    lines_utf16: PointUtf16::new(1 as u32, 0),
1653                    first_line_chars: 0,
1654                    last_line_chars: 0,
1655                    longest_row: 0,
1656                    longest_row_chars: 0,
1657                }));
1658            }
1659
1660            cursor.next(&());
1661        }
1662
1663        if range.end > *cursor.start() {
1664            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
1665                &range.end,
1666                Bias::Right,
1667                &(),
1668            )));
1669            if let Some(excerpt) = cursor.item() {
1670                range.end = cmp::max(*cursor.start(), range.end);
1671
1672                let excerpt_start = excerpt.range.start.to_offset(&excerpt.buffer);
1673                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
1674                summary.add_assign(
1675                    &excerpt
1676                        .buffer
1677                        .text_summary_for_range(excerpt_start..end_in_excerpt),
1678                );
1679            }
1680        }
1681
1682        summary
1683    }
1684
1685    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
1686    where
1687        D: TextDimension + Ord + Sub<D, Output = D>,
1688    {
1689        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1690        cursor.seek(&Some(&anchor.excerpt_id), Bias::Left, &());
1691        if cursor.item().is_none() {
1692            cursor.next(&());
1693        }
1694
1695        let mut position = D::from_text_summary(&cursor.start().text);
1696        if let Some(excerpt) = cursor.item() {
1697            if excerpt.id == anchor.excerpt_id && excerpt.buffer_id == anchor.buffer_id {
1698                let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1699                let excerpt_buffer_end = excerpt.range.end.summary::<D>(&excerpt.buffer);
1700                let buffer_position = cmp::min(
1701                    excerpt_buffer_end,
1702                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
1703                );
1704                if buffer_position > excerpt_buffer_start {
1705                    position.add_assign(&(buffer_position - excerpt_buffer_start));
1706                }
1707            }
1708        }
1709        position
1710    }
1711
1712    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
1713    where
1714        D: TextDimension + Ord + Sub<D, Output = D>,
1715        I: 'a + IntoIterator<Item = &'a Anchor>,
1716    {
1717        if let Some(excerpt) = self.as_singleton() {
1718            return excerpt
1719                .buffer
1720                .summaries_for_anchors(anchors.into_iter().map(|a| &a.text_anchor))
1721                .collect();
1722        }
1723
1724        let mut anchors = anchors.into_iter().peekable();
1725        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1726        let mut summaries = Vec::new();
1727        while let Some(anchor) = anchors.peek() {
1728            let excerpt_id = &anchor.excerpt_id;
1729            let buffer_id = anchor.buffer_id;
1730            let excerpt_anchors = iter::from_fn(|| {
1731                let anchor = anchors.peek()?;
1732                if anchor.excerpt_id == *excerpt_id && anchor.buffer_id == buffer_id {
1733                    Some(&anchors.next().unwrap().text_anchor)
1734                } else {
1735                    None
1736                }
1737            });
1738
1739            cursor.seek_forward(&Some(excerpt_id), Bias::Left, &());
1740            if cursor.item().is_none() {
1741                cursor.next(&());
1742            }
1743
1744            let position = D::from_text_summary(&cursor.start().text);
1745            if let Some(excerpt) = cursor.item() {
1746                if excerpt.id == *excerpt_id && excerpt.buffer_id == buffer_id {
1747                    let excerpt_buffer_start = excerpt.range.start.summary::<D>(&excerpt.buffer);
1748                    let excerpt_buffer_end = excerpt.range.end.summary::<D>(&excerpt.buffer);
1749                    summaries.extend(
1750                        excerpt
1751                            .buffer
1752                            .summaries_for_anchors::<D, _>(excerpt_anchors)
1753                            .map(move |summary| {
1754                                let summary = cmp::min(excerpt_buffer_end.clone(), summary);
1755                                let mut position = position.clone();
1756                                let excerpt_buffer_start = excerpt_buffer_start.clone();
1757                                if summary > excerpt_buffer_start {
1758                                    position.add_assign(&(summary - excerpt_buffer_start));
1759                                }
1760                                position
1761                            }),
1762                    );
1763                    continue;
1764                }
1765            }
1766
1767            summaries.extend(excerpt_anchors.map(|_| position.clone()));
1768        }
1769
1770        summaries
1771    }
1772
1773    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
1774    where
1775        I: 'a + IntoIterator<Item = &'a Anchor>,
1776    {
1777        let mut anchors = anchors.into_iter().enumerate().peekable();
1778        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1779        let mut result = Vec::new();
1780        while let Some((_, anchor)) = anchors.peek() {
1781            let old_excerpt_id = &anchor.excerpt_id;
1782
1783            // Find the location where this anchor's excerpt should be.
1784            cursor.seek_forward(&Some(old_excerpt_id), Bias::Left, &());
1785            if cursor.item().is_none() {
1786                cursor.next(&());
1787            }
1788
1789            let next_excerpt = cursor.item();
1790            let prev_excerpt = cursor.prev_item();
1791
1792            // Process all of the anchors for this excerpt.
1793            while let Some((_, anchor)) = anchors.peek() {
1794                if anchor.excerpt_id != *old_excerpt_id {
1795                    break;
1796                }
1797                let mut kept_position = false;
1798                let (anchor_ix, anchor) = anchors.next().unwrap();
1799                let mut anchor = anchor.clone();
1800
1801                // Leave min and max anchors unchanged.
1802                if *old_excerpt_id == ExcerptId::max() || *old_excerpt_id == ExcerptId::min() {
1803                    kept_position = true;
1804                }
1805                // If the old excerpt still exists at this location, then leave
1806                // the anchor unchanged.
1807                else if next_excerpt.map_or(false, |excerpt| {
1808                    excerpt.id == *old_excerpt_id && excerpt.contains(&anchor)
1809                }) {
1810                    kept_position = true;
1811                }
1812                // If the old excerpt no longer exists at this location, then attempt to
1813                // find an equivalent position for this anchor in an adjacent excerpt.
1814                else {
1815                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
1816                        if excerpt.contains(&anchor) {
1817                            anchor.excerpt_id = excerpt.id.clone();
1818                            kept_position = true;
1819                            break;
1820                        }
1821                    }
1822                }
1823                // If there's no adjacent excerpt that contains the anchor's position,
1824                // then report that the anchor has lost its position.
1825                if !kept_position {
1826                    anchor = if let Some(excerpt) = next_excerpt {
1827                        let mut text_anchor = excerpt
1828                            .range
1829                            .start
1830                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
1831                        if text_anchor
1832                            .cmp(&excerpt.range.end, &excerpt.buffer)
1833                            .unwrap()
1834                            .is_gt()
1835                        {
1836                            text_anchor = excerpt.range.end.clone();
1837                        }
1838                        Anchor {
1839                            buffer_id: excerpt.buffer_id,
1840                            excerpt_id: excerpt.id.clone(),
1841                            text_anchor,
1842                        }
1843                    } else if let Some(excerpt) = prev_excerpt {
1844                        let mut text_anchor = excerpt
1845                            .range
1846                            .end
1847                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
1848                        if text_anchor
1849                            .cmp(&excerpt.range.start, &excerpt.buffer)
1850                            .unwrap()
1851                            .is_lt()
1852                        {
1853                            text_anchor = excerpt.range.start.clone();
1854                        }
1855                        Anchor {
1856                            buffer_id: excerpt.buffer_id,
1857                            excerpt_id: excerpt.id.clone(),
1858                            text_anchor,
1859                        }
1860                    } else if anchor.text_anchor.bias == Bias::Left {
1861                        Anchor::min()
1862                    } else {
1863                        Anchor::max()
1864                    };
1865                }
1866
1867                result.push((anchor_ix, anchor, kept_position));
1868            }
1869        }
1870        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self).unwrap());
1871        result
1872    }
1873
1874    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
1875        self.anchor_at(position, Bias::Left)
1876    }
1877
1878    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
1879        self.anchor_at(position, Bias::Right)
1880    }
1881
1882    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
1883        let offset = position.to_offset(self);
1884        if let Some(excerpt) = self.as_singleton() {
1885            return Anchor {
1886                buffer_id: excerpt.buffer_id,
1887                excerpt_id: excerpt.id.clone(),
1888                text_anchor: excerpt.buffer.anchor_at(offset, bias),
1889            };
1890        }
1891
1892        let mut cursor = self.excerpts.cursor::<(usize, Option<&ExcerptId>)>();
1893        cursor.seek(&offset, Bias::Right, &());
1894        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
1895            cursor.prev(&());
1896        }
1897        if let Some(excerpt) = cursor.item() {
1898            let mut overshoot = offset.saturating_sub(cursor.start().0);
1899            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
1900                overshoot -= 1;
1901                bias = Bias::Right;
1902            }
1903
1904            let buffer_start = excerpt.range.start.to_offset(&excerpt.buffer);
1905            let text_anchor =
1906                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
1907            Anchor {
1908                buffer_id: excerpt.buffer_id,
1909                excerpt_id: excerpt.id.clone(),
1910                text_anchor,
1911            }
1912        } else if offset == 0 && bias == Bias::Left {
1913            Anchor::min()
1914        } else {
1915            Anchor::max()
1916        }
1917    }
1918
1919    pub fn anchor_in_excerpt(&self, excerpt_id: ExcerptId, text_anchor: text::Anchor) -> Anchor {
1920        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
1921        cursor.seek(&Some(&excerpt_id), Bias::Left, &());
1922        if let Some(excerpt) = cursor.item() {
1923            if excerpt.id == excerpt_id {
1924                let text_anchor = excerpt.clip_anchor(text_anchor);
1925                drop(cursor);
1926                return Anchor {
1927                    buffer_id: excerpt.buffer_id,
1928                    excerpt_id,
1929                    text_anchor,
1930                };
1931            }
1932        }
1933        panic!("excerpt not found");
1934    }
1935
1936    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
1937        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
1938            true
1939        } else if let Some((buffer_id, buffer_snapshot)) =
1940            self.buffer_snapshot_for_excerpt(&anchor.excerpt_id)
1941        {
1942            anchor.buffer_id == buffer_id && buffer_snapshot.can_resolve(&anchor.text_anchor)
1943        } else {
1944            false
1945        }
1946    }
1947
1948    pub fn excerpt_boundaries_in_range<'a, R, T>(
1949        &'a self,
1950        range: R,
1951    ) -> impl Iterator<Item = ExcerptBoundary> + 'a
1952    where
1953        R: RangeBounds<T>,
1954        T: ToOffset,
1955    {
1956        let start_offset;
1957        let start = match range.start_bound() {
1958            Bound::Included(start) => {
1959                start_offset = start.to_offset(self);
1960                Bound::Included(start_offset)
1961            }
1962            Bound::Excluded(start) => {
1963                start_offset = start.to_offset(self);
1964                Bound::Excluded(start_offset)
1965            }
1966            Bound::Unbounded => {
1967                start_offset = 0;
1968                Bound::Unbounded
1969            }
1970        };
1971        let end = match range.end_bound() {
1972            Bound::Included(end) => Bound::Included(end.to_offset(self)),
1973            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
1974            Bound::Unbounded => Bound::Unbounded,
1975        };
1976        let bounds = (start, end);
1977
1978        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1979        cursor.seek(&start_offset, Bias::Right, &());
1980        if cursor.item().is_none() {
1981            cursor.prev(&());
1982        }
1983        if !bounds.contains(&cursor.start().0) {
1984            cursor.next(&());
1985        }
1986
1987        let mut prev_buffer_id = cursor.prev_item().map(|excerpt| excerpt.buffer_id);
1988        std::iter::from_fn(move || {
1989            if self.singleton {
1990                None
1991            } else if bounds.contains(&cursor.start().0) {
1992                let excerpt = cursor.item()?;
1993                let starts_new_buffer = Some(excerpt.buffer_id) != prev_buffer_id;
1994                let boundary = ExcerptBoundary {
1995                    row: cursor.start().1.row,
1996                    buffer: excerpt.buffer.clone(),
1997                    range: excerpt.range.clone(),
1998                    starts_new_buffer,
1999                };
2000
2001                prev_buffer_id = Some(excerpt.buffer_id);
2002                cursor.next(&());
2003                Some(boundary)
2004            } else {
2005                None
2006            }
2007        })
2008    }
2009
2010    pub fn parse_count(&self) -> usize {
2011        self.parse_count
2012    }
2013
2014    pub fn enclosing_bracket_ranges<T: ToOffset>(
2015        &self,
2016        range: Range<T>,
2017    ) -> Option<(Range<usize>, Range<usize>)> {
2018        let range = range.start.to_offset(self)..range.end.to_offset(self);
2019
2020        let mut cursor = self.excerpts.cursor::<usize>();
2021        cursor.seek(&range.start, Bias::Right, &());
2022        let start_excerpt = cursor.item();
2023
2024        cursor.seek(&range.end, Bias::Right, &());
2025        let end_excerpt = cursor.item();
2026
2027        start_excerpt
2028            .zip(end_excerpt)
2029            .and_then(|(start_excerpt, end_excerpt)| {
2030                if start_excerpt.id != end_excerpt.id {
2031                    return None;
2032                }
2033
2034                let excerpt_buffer_start =
2035                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
2036                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
2037
2038                let start_in_buffer =
2039                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
2040                let end_in_buffer =
2041                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
2042                let (mut start_bracket_range, mut end_bracket_range) = start_excerpt
2043                    .buffer
2044                    .enclosing_bracket_ranges(start_in_buffer..end_in_buffer)?;
2045
2046                if start_bracket_range.start >= excerpt_buffer_start
2047                    && end_bracket_range.end < excerpt_buffer_end
2048                {
2049                    start_bracket_range.start =
2050                        cursor.start() + (start_bracket_range.start - excerpt_buffer_start);
2051                    start_bracket_range.end =
2052                        cursor.start() + (start_bracket_range.end - excerpt_buffer_start);
2053                    end_bracket_range.start =
2054                        cursor.start() + (end_bracket_range.start - excerpt_buffer_start);
2055                    end_bracket_range.end =
2056                        cursor.start() + (end_bracket_range.end - excerpt_buffer_start);
2057                    Some((start_bracket_range, end_bracket_range))
2058                } else {
2059                    None
2060                }
2061            })
2062    }
2063
2064    pub fn diagnostics_update_count(&self) -> usize {
2065        self.diagnostics_update_count
2066    }
2067
2068    pub fn trailing_excerpt_update_count(&self) -> usize {
2069        self.trailing_excerpt_update_count
2070    }
2071
2072    pub fn language(&self) -> Option<&Arc<Language>> {
2073        self.excerpts
2074            .iter()
2075            .next()
2076            .and_then(|excerpt| excerpt.buffer.language())
2077    }
2078
2079    pub fn is_dirty(&self) -> bool {
2080        self.is_dirty
2081    }
2082
2083    pub fn has_conflict(&self) -> bool {
2084        self.has_conflict
2085    }
2086
2087    pub fn diagnostic_group<'a, O>(
2088        &'a self,
2089        group_id: usize,
2090    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
2091    where
2092        O: text::FromAnchor + 'a,
2093    {
2094        self.as_singleton()
2095            .into_iter()
2096            .flat_map(move |excerpt| excerpt.buffer.diagnostic_group(group_id))
2097    }
2098
2099    pub fn diagnostics_in_range<'a, T, O>(
2100        &'a self,
2101        range: Range<T>,
2102    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
2103    where
2104        T: 'a + ToOffset,
2105        O: 'a + text::FromAnchor,
2106    {
2107        self.as_singleton().into_iter().flat_map(move |excerpt| {
2108            excerpt
2109                .buffer
2110                .diagnostics_in_range(range.start.to_offset(self)..range.end.to_offset(self))
2111        })
2112    }
2113
2114    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
2115        let range = range.start.to_offset(self)..range.end.to_offset(self);
2116
2117        let mut cursor = self.excerpts.cursor::<usize>();
2118        cursor.seek(&range.start, Bias::Right, &());
2119        let start_excerpt = cursor.item();
2120
2121        cursor.seek(&range.end, Bias::Right, &());
2122        let end_excerpt = cursor.item();
2123
2124        start_excerpt
2125            .zip(end_excerpt)
2126            .and_then(|(start_excerpt, end_excerpt)| {
2127                if start_excerpt.id != end_excerpt.id {
2128                    return None;
2129                }
2130
2131                let excerpt_buffer_start =
2132                    start_excerpt.range.start.to_offset(&start_excerpt.buffer);
2133                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
2134
2135                let start_in_buffer =
2136                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
2137                let end_in_buffer =
2138                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
2139                let mut ancestor_buffer_range = start_excerpt
2140                    .buffer
2141                    .range_for_syntax_ancestor(start_in_buffer..end_in_buffer)?;
2142                ancestor_buffer_range.start =
2143                    cmp::max(ancestor_buffer_range.start, excerpt_buffer_start);
2144                ancestor_buffer_range.end = cmp::min(ancestor_buffer_range.end, excerpt_buffer_end);
2145
2146                let start = cursor.start() + (ancestor_buffer_range.start - excerpt_buffer_start);
2147                let end = cursor.start() + (ancestor_buffer_range.end - excerpt_buffer_start);
2148                Some(start..end)
2149            })
2150    }
2151
2152    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
2153        let excerpt = self.as_singleton()?;
2154        let outline = excerpt.buffer.outline(theme)?;
2155        Some(Outline::new(
2156            outline
2157                .items
2158                .into_iter()
2159                .map(|item| OutlineItem {
2160                    depth: item.depth,
2161                    range: self.anchor_in_excerpt(excerpt.id.clone(), item.range.start)
2162                        ..self.anchor_in_excerpt(excerpt.id.clone(), item.range.end),
2163                    text: item.text,
2164                    highlight_ranges: item.highlight_ranges,
2165                    name_ranges: item.name_ranges,
2166                })
2167                .collect(),
2168        ))
2169    }
2170
2171    fn buffer_snapshot_for_excerpt<'a>(
2172        &'a self,
2173        excerpt_id: &'a ExcerptId,
2174    ) -> Option<(usize, &'a BufferSnapshot)> {
2175        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2176        cursor.seek(&Some(excerpt_id), Bias::Left, &());
2177        if let Some(excerpt) = cursor.item() {
2178            if excerpt.id == *excerpt_id {
2179                return Some((excerpt.buffer_id, &excerpt.buffer));
2180            }
2181        }
2182        None
2183    }
2184
2185    pub fn remote_selections_in_range<'a>(
2186        &'a self,
2187        range: &'a Range<Anchor>,
2188    ) -> impl 'a + Iterator<Item = (ReplicaId, Selection<Anchor>)> {
2189        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2190        cursor.seek(&Some(&range.start.excerpt_id), Bias::Left, &());
2191        cursor
2192            .take_while(move |excerpt| excerpt.id <= range.end.excerpt_id)
2193            .flat_map(move |excerpt| {
2194                let mut query_range = excerpt.range.start.clone()..excerpt.range.end.clone();
2195                if excerpt.id == range.start.excerpt_id {
2196                    query_range.start = range.start.text_anchor.clone();
2197                }
2198                if excerpt.id == range.end.excerpt_id {
2199                    query_range.end = range.end.text_anchor.clone();
2200                }
2201
2202                excerpt
2203                    .buffer
2204                    .remote_selections_in_range(query_range)
2205                    .flat_map(move |(replica_id, selections)| {
2206                        selections.map(move |selection| {
2207                            let mut start = Anchor {
2208                                buffer_id: excerpt.buffer_id,
2209                                excerpt_id: excerpt.id.clone(),
2210                                text_anchor: selection.start.clone(),
2211                            };
2212                            let mut end = Anchor {
2213                                buffer_id: excerpt.buffer_id,
2214                                excerpt_id: excerpt.id.clone(),
2215                                text_anchor: selection.end.clone(),
2216                            };
2217                            if range.start.cmp(&start, self).unwrap().is_gt() {
2218                                start = range.start.clone();
2219                            }
2220                            if range.end.cmp(&end, self).unwrap().is_lt() {
2221                                end = range.end.clone();
2222                            }
2223
2224                            (
2225                                replica_id,
2226                                Selection {
2227                                    id: selection.id,
2228                                    start,
2229                                    end,
2230                                    reversed: selection.reversed,
2231                                    goal: selection.goal,
2232                                },
2233                            )
2234                        })
2235                    })
2236            })
2237    }
2238}
2239
2240impl History {
2241    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
2242        self.transaction_depth += 1;
2243        if self.transaction_depth == 1 {
2244            let id = self.next_transaction_id.tick();
2245            self.undo_stack.push(Transaction {
2246                id,
2247                buffer_transactions: Default::default(),
2248                first_edit_at: now,
2249                last_edit_at: now,
2250                suppress_grouping: false,
2251            });
2252            Some(id)
2253        } else {
2254            None
2255        }
2256    }
2257
2258    fn end_transaction(
2259        &mut self,
2260        now: Instant,
2261        buffer_transactions: HashMap<usize, TransactionId>,
2262    ) -> bool {
2263        assert_ne!(self.transaction_depth, 0);
2264        self.transaction_depth -= 1;
2265        if self.transaction_depth == 0 {
2266            if buffer_transactions.is_empty() {
2267                self.undo_stack.pop();
2268                false
2269            } else {
2270                let transaction = self.undo_stack.last_mut().unwrap();
2271                transaction.last_edit_at = now;
2272                for (buffer_id, transaction_id) in buffer_transactions {
2273                    transaction
2274                        .buffer_transactions
2275                        .entry(buffer_id)
2276                        .or_insert(transaction_id);
2277                }
2278                true
2279            }
2280        } else {
2281            false
2282        }
2283    }
2284
2285    fn push_transaction<'a, T>(&mut self, buffer_transactions: T, now: Instant)
2286    where
2287        T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
2288    {
2289        assert_eq!(self.transaction_depth, 0);
2290        self.undo_stack.push(Transaction {
2291            id: self.next_transaction_id.tick(),
2292            buffer_transactions: buffer_transactions
2293                .into_iter()
2294                .map(|(buffer, transaction)| (buffer.id(), transaction.id))
2295                .collect(),
2296            first_edit_at: now,
2297            last_edit_at: now,
2298            suppress_grouping: false,
2299        });
2300    }
2301
2302    fn finalize_last_transaction(&mut self) {
2303        if let Some(transaction) = self.undo_stack.last_mut() {
2304            transaction.suppress_grouping = true;
2305        }
2306    }
2307
2308    fn pop_undo(&mut self) -> Option<&mut Transaction> {
2309        assert_eq!(self.transaction_depth, 0);
2310        if let Some(transaction) = self.undo_stack.pop() {
2311            self.redo_stack.push(transaction);
2312            self.redo_stack.last_mut()
2313        } else {
2314            None
2315        }
2316    }
2317
2318    fn pop_redo(&mut self) -> Option<&mut Transaction> {
2319        assert_eq!(self.transaction_depth, 0);
2320        if let Some(transaction) = self.redo_stack.pop() {
2321            self.undo_stack.push(transaction);
2322            self.undo_stack.last_mut()
2323        } else {
2324            None
2325        }
2326    }
2327
2328    fn group(&mut self) -> Option<TransactionId> {
2329        let mut new_len = self.undo_stack.len();
2330        let mut transactions = self.undo_stack.iter_mut();
2331
2332        if let Some(mut transaction) = transactions.next_back() {
2333            while let Some(prev_transaction) = transactions.next_back() {
2334                if !prev_transaction.suppress_grouping
2335                    && transaction.first_edit_at - prev_transaction.last_edit_at
2336                        <= self.group_interval
2337                {
2338                    transaction = prev_transaction;
2339                    new_len -= 1;
2340                } else {
2341                    break;
2342                }
2343            }
2344        }
2345
2346        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
2347        if let Some(last_transaction) = transactions_to_keep.last_mut() {
2348            if let Some(transaction) = transactions_to_merge.last() {
2349                last_transaction.last_edit_at = transaction.last_edit_at;
2350            }
2351            for to_merge in transactions_to_merge {
2352                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
2353                    last_transaction
2354                        .buffer_transactions
2355                        .entry(*buffer_id)
2356                        .or_insert(*transaction_id);
2357                }
2358            }
2359        }
2360
2361        self.undo_stack.truncate(new_len);
2362        self.undo_stack.last().map(|t| t.id)
2363    }
2364}
2365
2366impl Excerpt {
2367    fn new(
2368        id: ExcerptId,
2369        buffer_id: usize,
2370        buffer: BufferSnapshot,
2371        range: Range<text::Anchor>,
2372        has_trailing_newline: bool,
2373    ) -> Self {
2374        Excerpt {
2375            id,
2376            max_buffer_row: range.end.to_point(&buffer).row,
2377            text_summary: buffer.text_summary_for_range::<TextSummary, _>(range.to_offset(&buffer)),
2378            buffer_id,
2379            buffer,
2380            range,
2381            has_trailing_newline,
2382        }
2383    }
2384
2385    fn chunks_in_range<'a>(
2386        &'a self,
2387        range: Range<usize>,
2388        language_aware: bool,
2389    ) -> ExcerptChunks<'a> {
2390        let content_start = self.range.start.to_offset(&self.buffer);
2391        let chunks_start = content_start + range.start;
2392        let chunks_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2393
2394        let footer_height = if self.has_trailing_newline
2395            && range.start <= self.text_summary.bytes
2396            && range.end > self.text_summary.bytes
2397        {
2398            1
2399        } else {
2400            0
2401        };
2402
2403        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
2404
2405        ExcerptChunks {
2406            content_chunks,
2407            footer_height,
2408        }
2409    }
2410
2411    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
2412        let content_start = self.range.start.to_offset(&self.buffer);
2413        let bytes_start = content_start + range.start;
2414        let bytes_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2415        let footer_height = if self.has_trailing_newline
2416            && range.start <= self.text_summary.bytes
2417            && range.end > self.text_summary.bytes
2418        {
2419            1
2420        } else {
2421            0
2422        };
2423        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
2424
2425        ExcerptBytes {
2426            content_bytes,
2427            footer_height,
2428        }
2429    }
2430
2431    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
2432        if text_anchor
2433            .cmp(&self.range.start, &self.buffer)
2434            .unwrap()
2435            .is_lt()
2436        {
2437            self.range.start.clone()
2438        } else if text_anchor
2439            .cmp(&self.range.end, &self.buffer)
2440            .unwrap()
2441            .is_gt()
2442        {
2443            self.range.end.clone()
2444        } else {
2445            text_anchor
2446        }
2447    }
2448
2449    fn contains(&self, anchor: &Anchor) -> bool {
2450        self.buffer_id == anchor.buffer_id
2451            && self
2452                .range
2453                .start
2454                .cmp(&anchor.text_anchor, &self.buffer)
2455                .unwrap()
2456                .is_le()
2457            && self
2458                .range
2459                .end
2460                .cmp(&anchor.text_anchor, &self.buffer)
2461                .unwrap()
2462                .is_ge()
2463    }
2464}
2465
2466impl fmt::Debug for Excerpt {
2467    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2468        f.debug_struct("Excerpt")
2469            .field("id", &self.id)
2470            .field("buffer_id", &self.buffer_id)
2471            .field("range", &self.range)
2472            .field("text_summary", &self.text_summary)
2473            .field("has_trailing_newline", &self.has_trailing_newline)
2474            .finish()
2475    }
2476}
2477
2478impl sum_tree::Item for Excerpt {
2479    type Summary = ExcerptSummary;
2480
2481    fn summary(&self) -> Self::Summary {
2482        let mut text = self.text_summary.clone();
2483        if self.has_trailing_newline {
2484            text += TextSummary::from("\n");
2485        }
2486        ExcerptSummary {
2487            excerpt_id: self.id.clone(),
2488            max_buffer_row: self.max_buffer_row,
2489            text,
2490        }
2491    }
2492}
2493
2494impl sum_tree::Summary for ExcerptSummary {
2495    type Context = ();
2496
2497    fn add_summary(&mut self, summary: &Self, _: &()) {
2498        debug_assert!(summary.excerpt_id > self.excerpt_id);
2499        self.excerpt_id = summary.excerpt_id.clone();
2500        self.text.add_summary(&summary.text, &());
2501        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
2502    }
2503}
2504
2505impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
2506    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2507        *self += &summary.text;
2508    }
2509}
2510
2511impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
2512    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2513        *self += summary.text.bytes;
2514    }
2515}
2516
2517impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
2518    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2519        Ord::cmp(self, &cursor_location.text.bytes)
2520    }
2521}
2522
2523impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Option<&'a ExcerptId> {
2524    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2525        Ord::cmp(self, &Some(&cursor_location.excerpt_id))
2526    }
2527}
2528
2529impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
2530    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2531        *self += summary.text.lines;
2532    }
2533}
2534
2535impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
2536    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2537        *self += summary.text.lines_utf16
2538    }
2539}
2540
2541impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a ExcerptId> {
2542    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2543        *self = Some(&summary.excerpt_id);
2544    }
2545}
2546
2547impl<'a> MultiBufferRows<'a> {
2548    pub fn seek(&mut self, row: u32) {
2549        self.buffer_row_range = 0..0;
2550
2551        self.excerpts
2552            .seek_forward(&Point::new(row, 0), Bias::Right, &());
2553        if self.excerpts.item().is_none() {
2554            self.excerpts.prev(&());
2555
2556            if self.excerpts.item().is_none() && row == 0 {
2557                self.buffer_row_range = 0..1;
2558                return;
2559            }
2560        }
2561
2562        if let Some(excerpt) = self.excerpts.item() {
2563            let overshoot = row - self.excerpts.start().row;
2564            let excerpt_start = excerpt.range.start.to_point(&excerpt.buffer).row;
2565            self.buffer_row_range.start = excerpt_start + overshoot;
2566            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
2567        }
2568    }
2569}
2570
2571impl<'a> Iterator for MultiBufferRows<'a> {
2572    type Item = Option<u32>;
2573
2574    fn next(&mut self) -> Option<Self::Item> {
2575        loop {
2576            if !self.buffer_row_range.is_empty() {
2577                let row = Some(self.buffer_row_range.start);
2578                self.buffer_row_range.start += 1;
2579                return Some(row);
2580            }
2581            self.excerpts.item()?;
2582            self.excerpts.next(&());
2583            let excerpt = self.excerpts.item()?;
2584            self.buffer_row_range.start = excerpt.range.start.to_point(&excerpt.buffer).row;
2585            self.buffer_row_range.end =
2586                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
2587        }
2588    }
2589}
2590
2591impl<'a> MultiBufferChunks<'a> {
2592    pub fn offset(&self) -> usize {
2593        self.range.start
2594    }
2595
2596    pub fn seek(&mut self, offset: usize) {
2597        self.range.start = offset;
2598        self.excerpts.seek(&offset, Bias::Right, &());
2599        if let Some(excerpt) = self.excerpts.item() {
2600            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2601                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
2602                self.language_aware,
2603            ));
2604        } else {
2605            self.excerpt_chunks = None;
2606        }
2607    }
2608}
2609
2610impl<'a> Iterator for MultiBufferChunks<'a> {
2611    type Item = Chunk<'a>;
2612
2613    fn next(&mut self) -> Option<Self::Item> {
2614        if self.range.is_empty() {
2615            None
2616        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
2617            self.range.start += chunk.text.len();
2618            Some(chunk)
2619        } else {
2620            self.excerpts.next(&());
2621            let excerpt = self.excerpts.item()?;
2622            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2623                0..self.range.end - self.excerpts.start(),
2624                self.language_aware,
2625            ));
2626            self.next()
2627        }
2628    }
2629}
2630
2631impl<'a> MultiBufferBytes<'a> {
2632    fn consume(&mut self, len: usize) {
2633        self.range.start += len;
2634        self.chunk = &self.chunk[len..];
2635
2636        if !self.range.is_empty() && self.chunk.is_empty() {
2637            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
2638                self.chunk = chunk;
2639            } else {
2640                self.excerpts.next(&());
2641                if let Some(excerpt) = self.excerpts.item() {
2642                    let mut excerpt_bytes =
2643                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
2644                    self.chunk = excerpt_bytes.next().unwrap();
2645                    self.excerpt_bytes = Some(excerpt_bytes);
2646                }
2647            }
2648        }
2649    }
2650}
2651
2652impl<'a> Iterator for MultiBufferBytes<'a> {
2653    type Item = &'a [u8];
2654
2655    fn next(&mut self) -> Option<Self::Item> {
2656        let chunk = self.chunk;
2657        if chunk.is_empty() {
2658            None
2659        } else {
2660            self.consume(chunk.len());
2661            Some(chunk)
2662        }
2663    }
2664}
2665
2666impl<'a> io::Read for MultiBufferBytes<'a> {
2667    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
2668        let len = cmp::min(buf.len(), self.chunk.len());
2669        buf[..len].copy_from_slice(&self.chunk[..len]);
2670        if len > 0 {
2671            self.consume(len);
2672        }
2673        Ok(len)
2674    }
2675}
2676
2677impl<'a> Iterator for ExcerptBytes<'a> {
2678    type Item = &'a [u8];
2679
2680    fn next(&mut self) -> Option<Self::Item> {
2681        if let Some(chunk) = self.content_bytes.next() {
2682            if !chunk.is_empty() {
2683                return Some(chunk);
2684            }
2685        }
2686
2687        if self.footer_height > 0 {
2688            let result = &NEWLINES[..self.footer_height];
2689            self.footer_height = 0;
2690            return Some(result);
2691        }
2692
2693        None
2694    }
2695}
2696
2697impl<'a> Iterator for ExcerptChunks<'a> {
2698    type Item = Chunk<'a>;
2699
2700    fn next(&mut self) -> Option<Self::Item> {
2701        if let Some(chunk) = self.content_chunks.next() {
2702            return Some(chunk);
2703        }
2704
2705        if self.footer_height > 0 {
2706            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
2707            self.footer_height = 0;
2708            return Some(Chunk {
2709                text,
2710                ..Default::default()
2711            });
2712        }
2713
2714        None
2715    }
2716}
2717
2718impl ToOffset for Point {
2719    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2720        snapshot.point_to_offset(*self)
2721    }
2722}
2723
2724impl ToOffset for PointUtf16 {
2725    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2726        snapshot.point_utf16_to_offset(*self)
2727    }
2728}
2729
2730impl ToOffset for usize {
2731    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
2732        assert!(*self <= snapshot.len(), "offset is out of range");
2733        *self
2734    }
2735}
2736
2737impl ToPoint for usize {
2738    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
2739        snapshot.offset_to_point(*self)
2740    }
2741}
2742
2743impl ToPoint for Point {
2744    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
2745        *self
2746    }
2747}
2748
2749impl ToPointUtf16 for usize {
2750    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
2751        snapshot.offset_to_point_utf16(*self)
2752    }
2753}
2754
2755impl ToPointUtf16 for Point {
2756    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
2757        snapshot.point_to_point_utf16(*self)
2758    }
2759}
2760
2761impl ToPointUtf16 for PointUtf16 {
2762    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
2763        *self
2764    }
2765}
2766
2767pub fn char_kind(c: char) -> CharKind {
2768    if c == '\n' {
2769        CharKind::Newline
2770    } else if c.is_whitespace() {
2771        CharKind::Whitespace
2772    } else if c.is_alphanumeric() || c == '_' {
2773        CharKind::Word
2774    } else {
2775        CharKind::Punctuation
2776    }
2777}
2778
2779#[cfg(test)]
2780mod tests {
2781    use super::*;
2782    use gpui::MutableAppContext;
2783    use language::{Buffer, Rope};
2784    use rand::prelude::*;
2785    use std::env;
2786    use text::{Point, RandomCharIter};
2787    use util::test::sample_text;
2788
2789    #[gpui::test]
2790    fn test_singleton_multibuffer(cx: &mut MutableAppContext) {
2791        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2792        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
2793
2794        let snapshot = multibuffer.read(cx).snapshot(cx);
2795        assert_eq!(snapshot.text(), buffer.read(cx).text());
2796
2797        assert_eq!(
2798            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2799            (0..buffer.read(cx).row_count())
2800                .map(Some)
2801                .collect::<Vec<_>>()
2802        );
2803
2804        buffer.update(cx, |buffer, cx| buffer.edit([1..3], "XXX\n", cx));
2805        let snapshot = multibuffer.read(cx).snapshot(cx);
2806
2807        assert_eq!(snapshot.text(), buffer.read(cx).text());
2808        assert_eq!(
2809            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2810            (0..buffer.read(cx).row_count())
2811                .map(Some)
2812                .collect::<Vec<_>>()
2813        );
2814    }
2815
2816    #[gpui::test]
2817    fn test_remote_multibuffer(cx: &mut MutableAppContext) {
2818        let host_buffer = cx.add_model(|cx| Buffer::new(0, "a", cx));
2819        let guest_buffer = cx.add_model(|cx| {
2820            let message = host_buffer.read(cx).to_proto();
2821            Buffer::from_proto(1, message, None, cx).unwrap()
2822        });
2823        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
2824        let snapshot = multibuffer.read(cx).snapshot(cx);
2825        assert_eq!(snapshot.text(), "a");
2826
2827        guest_buffer.update(cx, |buffer, cx| buffer.edit([1..1], "b", cx));
2828        let snapshot = multibuffer.read(cx).snapshot(cx);
2829        assert_eq!(snapshot.text(), "ab");
2830
2831        guest_buffer.update(cx, |buffer, cx| buffer.edit([2..2], "c", cx));
2832        let snapshot = multibuffer.read(cx).snapshot(cx);
2833        assert_eq!(snapshot.text(), "abc");
2834    }
2835
2836    #[gpui::test]
2837    fn test_excerpt_buffer(cx: &mut MutableAppContext) {
2838        let buffer_1 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
2839        let buffer_2 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'g'), cx));
2840        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
2841
2842        let subscription = multibuffer.update(cx, |multibuffer, cx| {
2843            let subscription = multibuffer.subscribe();
2844            multibuffer.push_excerpts(buffer_1.clone(), [Point::new(1, 2)..Point::new(2, 5)], cx);
2845            assert_eq!(
2846                subscription.consume().into_inner(),
2847                [Edit {
2848                    old: 0..0,
2849                    new: 0..10
2850                }]
2851            );
2852
2853            multibuffer.push_excerpts(buffer_1.clone(), [Point::new(3, 3)..Point::new(4, 4)], cx);
2854            multibuffer.push_excerpts(buffer_2.clone(), [Point::new(3, 1)..Point::new(3, 3)], cx);
2855            assert_eq!(
2856                subscription.consume().into_inner(),
2857                [Edit {
2858                    old: 10..10,
2859                    new: 10..22
2860                }]
2861            );
2862
2863            subscription
2864        });
2865
2866        let snapshot = multibuffer.read(cx).snapshot(cx);
2867        assert_eq!(
2868            snapshot.text(),
2869            concat!(
2870                "bbbb\n",  // Preserve newlines
2871                "ccccc\n", //
2872                "ddd\n",   //
2873                "eeee\n",  //
2874                "jj"       //
2875            )
2876        );
2877        assert_eq!(
2878            snapshot.buffer_rows(0).collect::<Vec<_>>(),
2879            [Some(1), Some(2), Some(3), Some(4), Some(3)]
2880        );
2881        assert_eq!(
2882            snapshot.buffer_rows(2).collect::<Vec<_>>(),
2883            [Some(3), Some(4), Some(3)]
2884        );
2885        assert_eq!(snapshot.buffer_rows(4).collect::<Vec<_>>(), [Some(3)]);
2886        assert_eq!(snapshot.buffer_rows(5).collect::<Vec<_>>(), []);
2887
2888        assert_eq!(
2889            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
2890            &[
2891                (0, "bbbb\nccccc".to_string(), true),
2892                (2, "ddd\neeee".to_string(), false),
2893                (4, "jj".to_string(), true),
2894            ]
2895        );
2896        assert_eq!(
2897            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
2898            &[(0, "bbbb\nccccc".to_string(), true)]
2899        );
2900        assert_eq!(
2901            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
2902            &[]
2903        );
2904        assert_eq!(
2905            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
2906            &[]
2907        );
2908        assert_eq!(
2909            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
2910            &[(2, "ddd\neeee".to_string(), false)]
2911        );
2912        assert_eq!(
2913            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
2914            &[(2, "ddd\neeee".to_string(), false)]
2915        );
2916        assert_eq!(
2917            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
2918            &[(2, "ddd\neeee".to_string(), false)]
2919        );
2920        assert_eq!(
2921            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
2922            &[(4, "jj".to_string(), true)]
2923        );
2924        assert_eq!(
2925            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
2926            &[]
2927        );
2928
2929        buffer_1.update(cx, |buffer, cx| {
2930            buffer.edit(
2931                [
2932                    Point::new(0, 0)..Point::new(0, 0),
2933                    Point::new(2, 1)..Point::new(2, 3),
2934                ],
2935                "\n",
2936                cx,
2937            );
2938        });
2939
2940        let snapshot = multibuffer.read(cx).snapshot(cx);
2941        assert_eq!(
2942            snapshot.text(),
2943            concat!(
2944                "bbbb\n", // Preserve newlines
2945                "c\n",    //
2946                "cc\n",   //
2947                "ddd\n",  //
2948                "eeee\n", //
2949                "jj"      //
2950            )
2951        );
2952
2953        assert_eq!(
2954            subscription.consume().into_inner(),
2955            [Edit {
2956                old: 6..8,
2957                new: 6..7
2958            }]
2959        );
2960
2961        let snapshot = multibuffer.read(cx).snapshot(cx);
2962        assert_eq!(
2963            snapshot.clip_point(Point::new(0, 5), Bias::Left),
2964            Point::new(0, 4)
2965        );
2966        assert_eq!(
2967            snapshot.clip_point(Point::new(0, 5), Bias::Right),
2968            Point::new(0, 4)
2969        );
2970        assert_eq!(
2971            snapshot.clip_point(Point::new(5, 1), Bias::Right),
2972            Point::new(5, 1)
2973        );
2974        assert_eq!(
2975            snapshot.clip_point(Point::new(5, 2), Bias::Right),
2976            Point::new(5, 2)
2977        );
2978        assert_eq!(
2979            snapshot.clip_point(Point::new(5, 3), Bias::Right),
2980            Point::new(5, 2)
2981        );
2982
2983        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
2984            let buffer_2_excerpt_id = multibuffer.excerpt_ids_for_buffer(&buffer_2)[0].clone();
2985            multibuffer.remove_excerpts(&[buffer_2_excerpt_id], cx);
2986            multibuffer.snapshot(cx)
2987        });
2988
2989        assert_eq!(
2990            snapshot.text(),
2991            concat!(
2992                "bbbb\n", // Preserve newlines
2993                "c\n",    //
2994                "cc\n",   //
2995                "ddd\n",  //
2996                "eeee",   //
2997            )
2998        );
2999
3000        fn boundaries_in_range(
3001            range: Range<Point>,
3002            snapshot: &MultiBufferSnapshot,
3003        ) -> Vec<(u32, String, bool)> {
3004            snapshot
3005                .excerpt_boundaries_in_range(range)
3006                .map(|boundary| {
3007                    (
3008                        boundary.row,
3009                        boundary
3010                            .buffer
3011                            .text_for_range(boundary.range)
3012                            .collect::<String>(),
3013                        boundary.starts_new_buffer,
3014                    )
3015                })
3016                .collect::<Vec<_>>()
3017        }
3018    }
3019
3020    #[gpui::test]
3021    fn test_excerpts_with_context_lines(cx: &mut MutableAppContext) {
3022        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(20, 3, 'a'), cx));
3023        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3024        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
3025            multibuffer.push_excerpts_with_context_lines(
3026                buffer.clone(),
3027                vec![
3028                    Point::new(3, 2)..Point::new(4, 2),
3029                    Point::new(7, 1)..Point::new(7, 3),
3030                    Point::new(15, 0)..Point::new(15, 0),
3031                ],
3032                2,
3033                cx,
3034            )
3035        });
3036
3037        let snapshot = multibuffer.read(cx).snapshot(cx);
3038        assert_eq!(
3039            snapshot.text(),
3040            "bbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\n\nnnn\nooo\nppp\nqqq\nrrr\n"
3041        );
3042
3043        assert_eq!(
3044            anchor_ranges
3045                .iter()
3046                .map(|range| range.to_point(&snapshot))
3047                .collect::<Vec<_>>(),
3048            vec![
3049                Point::new(2, 2)..Point::new(3, 2),
3050                Point::new(6, 1)..Point::new(6, 3),
3051                Point::new(12, 0)..Point::new(12, 0)
3052            ]
3053        );
3054    }
3055
3056    #[gpui::test]
3057    fn test_empty_excerpt_buffer(cx: &mut MutableAppContext) {
3058        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3059
3060        let snapshot = multibuffer.read(cx).snapshot(cx);
3061        assert_eq!(snapshot.text(), "");
3062        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), &[Some(0)]);
3063        assert_eq!(snapshot.buffer_rows(1).collect::<Vec<_>>(), &[]);
3064    }
3065
3066    #[gpui::test]
3067    fn test_singleton_multibuffer_anchors(cx: &mut MutableAppContext) {
3068        let buffer = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3069        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
3070        let old_snapshot = multibuffer.read(cx).snapshot(cx);
3071        buffer.update(cx, |buffer, cx| {
3072            buffer.edit([0..0], "X", cx);
3073            buffer.edit([5..5], "Y", cx);
3074        });
3075        let new_snapshot = multibuffer.read(cx).snapshot(cx);
3076
3077        assert_eq!(old_snapshot.text(), "abcd");
3078        assert_eq!(new_snapshot.text(), "XabcdY");
3079
3080        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
3081        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
3082        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
3083        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
3084    }
3085
3086    #[gpui::test]
3087    fn test_multibuffer_anchors(cx: &mut MutableAppContext) {
3088        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3089        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "efghi", cx));
3090        let multibuffer = cx.add_model(|cx| {
3091            let mut multibuffer = MultiBuffer::new(0);
3092            multibuffer.push_excerpts(buffer_1.clone(), [0..4], cx);
3093            multibuffer.push_excerpts(buffer_2.clone(), [0..5], cx);
3094            multibuffer
3095        });
3096        let old_snapshot = multibuffer.read(cx).snapshot(cx);
3097
3098        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
3099        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
3100        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
3101        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
3102        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
3103        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
3104
3105        buffer_1.update(cx, |buffer, cx| {
3106            buffer.edit([0..0], "W", cx);
3107            buffer.edit([5..5], "X", cx);
3108        });
3109        buffer_2.update(cx, |buffer, cx| {
3110            buffer.edit([0..0], "Y", cx);
3111            buffer.edit([6..0], "Z", cx);
3112        });
3113        let new_snapshot = multibuffer.read(cx).snapshot(cx);
3114
3115        assert_eq!(old_snapshot.text(), "abcd\nefghi");
3116        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
3117
3118        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
3119        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
3120        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
3121        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
3122        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
3123        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
3124        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
3125        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
3126        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
3127        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
3128    }
3129
3130    #[gpui::test]
3131    fn test_multibuffer_resolving_anchors_after_replacing_their_excerpts(
3132        cx: &mut MutableAppContext,
3133    ) {
3134        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3135        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "ABCDEFGHIJKLMNOP", cx));
3136        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3137
3138        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
3139        // Add an excerpt from buffer 1 that spans this new insertion.
3140        buffer_1.update(cx, |buffer, cx| buffer.edit([4..4], "123", cx));
3141        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
3142            multibuffer
3143                .push_excerpts(buffer_1.clone(), [0..7], cx)
3144                .pop()
3145                .unwrap()
3146        });
3147
3148        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
3149        assert_eq!(snapshot_1.text(), "abcd123");
3150
3151        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
3152        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
3153            multibuffer.remove_excerpts([&excerpt_id_1], cx);
3154            let mut ids = multibuffer
3155                .push_excerpts(buffer_2.clone(), [0..4, 6..10, 12..16], cx)
3156                .into_iter();
3157            (ids.next().unwrap(), ids.next().unwrap())
3158        });
3159        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
3160        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
3161
3162        // The old excerpt id has been reused.
3163        assert_eq!(excerpt_id_2, excerpt_id_1);
3164
3165        // Resolve some anchors from the previous snapshot in the new snapshot.
3166        // Although there is still an excerpt with the same id, it is for
3167        // a different buffer, so we don't attempt to resolve the old text
3168        // anchor in the new buffer.
3169        assert_eq!(
3170            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
3171            0
3172        );
3173        assert_eq!(
3174            snapshot_2.summaries_for_anchors::<usize, _>(&[
3175                snapshot_1.anchor_before(2),
3176                snapshot_1.anchor_after(3)
3177            ]),
3178            vec![0, 0]
3179        );
3180        let refresh =
3181            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
3182        assert_eq!(
3183            refresh,
3184            &[
3185                (0, snapshot_2.anchor_before(0), false),
3186                (1, snapshot_2.anchor_after(0), false),
3187            ]
3188        );
3189
3190        // Replace the middle excerpt with a smaller excerpt in buffer 2,
3191        // that intersects the old excerpt.
3192        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
3193            multibuffer.remove_excerpts([&excerpt_id_3], cx);
3194            multibuffer
3195                .insert_excerpts_after(&excerpt_id_3, buffer_2.clone(), [5..8], cx)
3196                .pop()
3197                .unwrap()
3198        });
3199
3200        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
3201        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
3202        assert_ne!(excerpt_id_5, excerpt_id_3);
3203
3204        // Resolve some anchors from the previous snapshot in the new snapshot.
3205        // The anchor in the middle excerpt snaps to the beginning of the
3206        // excerpt, since it is not
3207        let anchors = [
3208            snapshot_2.anchor_before(0),
3209            snapshot_2.anchor_after(2),
3210            snapshot_2.anchor_after(6),
3211            snapshot_2.anchor_after(14),
3212        ];
3213        assert_eq!(
3214            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
3215            &[0, 2, 9, 13]
3216        );
3217
3218        let new_anchors = snapshot_3.refresh_anchors(&anchors);
3219        assert_eq!(
3220            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
3221            &[(0, true), (1, true), (2, true), (3, true)]
3222        );
3223        assert_eq!(
3224            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
3225            &[0, 2, 7, 13]
3226        );
3227    }
3228
3229    #[gpui::test(iterations = 100)]
3230    fn test_random_multibuffer(cx: &mut MutableAppContext, mut rng: StdRng) {
3231        let operations = env::var("OPERATIONS")
3232            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
3233            .unwrap_or(10);
3234
3235        let mut buffers: Vec<ModelHandle<Buffer>> = Vec::new();
3236        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3237        let mut excerpt_ids = Vec::new();
3238        let mut expected_excerpts = Vec::<(ModelHandle<Buffer>, Range<text::Anchor>)>::new();
3239        let mut anchors = Vec::new();
3240        let mut old_versions = Vec::new();
3241
3242        for _ in 0..operations {
3243            match rng.gen_range(0..100) {
3244                0..=19 if !buffers.is_empty() => {
3245                    let buffer = buffers.choose(&mut rng).unwrap();
3246                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
3247                }
3248                20..=29 if !expected_excerpts.is_empty() => {
3249                    let mut ids_to_remove = vec![];
3250                    for _ in 0..rng.gen_range(1..=3) {
3251                        if expected_excerpts.is_empty() {
3252                            break;
3253                        }
3254
3255                        let ix = rng.gen_range(0..expected_excerpts.len());
3256                        ids_to_remove.push(excerpt_ids.remove(ix));
3257                        let (buffer, range) = expected_excerpts.remove(ix);
3258                        let buffer = buffer.read(cx);
3259                        log::info!(
3260                            "Removing excerpt {}: {:?}",
3261                            ix,
3262                            buffer
3263                                .text_for_range(range.to_offset(&buffer))
3264                                .collect::<String>(),
3265                        );
3266                    }
3267                    ids_to_remove.sort_unstable();
3268                    multibuffer.update(cx, |multibuffer, cx| {
3269                        multibuffer.remove_excerpts(&ids_to_remove, cx)
3270                    });
3271                }
3272                30..=39 if !expected_excerpts.is_empty() => {
3273                    let multibuffer = multibuffer.read(cx).read(cx);
3274                    let offset =
3275                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
3276                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
3277                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
3278                    anchors.push(multibuffer.anchor_at(offset, bias));
3279                    anchors.sort_by(|a, b| a.cmp(&b, &multibuffer).unwrap());
3280                }
3281                40..=44 if !anchors.is_empty() => {
3282                    let multibuffer = multibuffer.read(cx).read(cx);
3283
3284                    anchors = multibuffer
3285                        .refresh_anchors(&anchors)
3286                        .into_iter()
3287                        .map(|a| a.1)
3288                        .collect();
3289
3290                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
3291                    // overshoot its boundaries.
3292                    let mut cursor = multibuffer.excerpts.cursor::<Option<&ExcerptId>>();
3293                    for anchor in &anchors {
3294                        if anchor.excerpt_id == ExcerptId::min()
3295                            || anchor.excerpt_id == ExcerptId::max()
3296                        {
3297                            continue;
3298                        }
3299
3300                        cursor.seek_forward(&Some(&anchor.excerpt_id), Bias::Left, &());
3301                        let excerpt = cursor.item().unwrap();
3302                        assert_eq!(excerpt.id, anchor.excerpt_id);
3303                        assert!(excerpt.contains(anchor));
3304                    }
3305                }
3306                _ => {
3307                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
3308                        let base_text = RandomCharIter::new(&mut rng).take(10).collect::<String>();
3309                        buffers.push(cx.add_model(|cx| Buffer::new(0, base_text, cx)));
3310                        buffers.last().unwrap()
3311                    } else {
3312                        buffers.choose(&mut rng).unwrap()
3313                    };
3314
3315                    let buffer = buffer_handle.read(cx);
3316                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3317                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3318                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
3319                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
3320                    let prev_excerpt_id = excerpt_ids
3321                        .get(prev_excerpt_ix)
3322                        .cloned()
3323                        .unwrap_or(ExcerptId::max());
3324                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
3325
3326                    log::info!(
3327                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
3328                        excerpt_ix,
3329                        expected_excerpts.len(),
3330                        buffer_handle.id(),
3331                        buffer.text(),
3332                        start_ix..end_ix,
3333                        &buffer.text()[start_ix..end_ix]
3334                    );
3335
3336                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
3337                        multibuffer
3338                            .insert_excerpts_after(
3339                                &prev_excerpt_id,
3340                                buffer_handle.clone(),
3341                                [start_ix..end_ix],
3342                                cx,
3343                            )
3344                            .pop()
3345                            .unwrap()
3346                    });
3347
3348                    excerpt_ids.insert(excerpt_ix, excerpt_id);
3349                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
3350                }
3351            }
3352
3353            if rng.gen_bool(0.3) {
3354                multibuffer.update(cx, |multibuffer, cx| {
3355                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
3356                })
3357            }
3358
3359            let snapshot = multibuffer.read(cx).snapshot(cx);
3360
3361            let mut excerpt_starts = Vec::new();
3362            let mut expected_text = String::new();
3363            let mut expected_buffer_rows = Vec::new();
3364            for (buffer, range) in &expected_excerpts {
3365                let buffer = buffer.read(cx);
3366                let buffer_range = range.to_offset(buffer);
3367
3368                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
3369                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
3370                expected_text.push('\n');
3371
3372                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
3373                    ..=buffer.offset_to_point(buffer_range.end).row;
3374                for row in buffer_row_range {
3375                    expected_buffer_rows.push(Some(row));
3376                }
3377            }
3378            // Remove final trailing newline.
3379            if !expected_excerpts.is_empty() {
3380                expected_text.pop();
3381            }
3382
3383            // Always report one buffer row
3384            if expected_buffer_rows.is_empty() {
3385                expected_buffer_rows.push(Some(0));
3386            }
3387
3388            assert_eq!(snapshot.text(), expected_text);
3389            log::info!("MultiBuffer text: {:?}", expected_text);
3390
3391            assert_eq!(
3392                snapshot.buffer_rows(0).collect::<Vec<_>>(),
3393                expected_buffer_rows,
3394            );
3395
3396            for _ in 0..5 {
3397                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
3398                assert_eq!(
3399                    snapshot.buffer_rows(start_row as u32).collect::<Vec<_>>(),
3400                    &expected_buffer_rows[start_row..],
3401                    "buffer_rows({})",
3402                    start_row
3403                );
3404            }
3405
3406            assert_eq!(
3407                snapshot.max_buffer_row(),
3408                expected_buffer_rows
3409                    .into_iter()
3410                    .filter_map(|r| r)
3411                    .max()
3412                    .unwrap()
3413            );
3414
3415            let mut excerpt_starts = excerpt_starts.into_iter();
3416            for (buffer, range) in &expected_excerpts {
3417                let buffer_id = buffer.id();
3418                let buffer = buffer.read(cx);
3419                let buffer_range = range.to_offset(buffer);
3420                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
3421                let buffer_start_point_utf16 =
3422                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
3423
3424                let excerpt_start = excerpt_starts.next().unwrap();
3425                let mut offset = excerpt_start.bytes;
3426                let mut buffer_offset = buffer_range.start;
3427                let mut point = excerpt_start.lines;
3428                let mut buffer_point = buffer_start_point;
3429                let mut point_utf16 = excerpt_start.lines_utf16;
3430                let mut buffer_point_utf16 = buffer_start_point_utf16;
3431                for ch in buffer
3432                    .snapshot()
3433                    .chunks(buffer_range.clone(), false)
3434                    .flat_map(|c| c.text.chars())
3435                {
3436                    for _ in 0..ch.len_utf8() {
3437                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
3438                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
3439                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
3440                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
3441                        assert_eq!(
3442                            left_offset,
3443                            excerpt_start.bytes + (buffer_left_offset - buffer_range.start),
3444                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
3445                            offset,
3446                            buffer_id,
3447                            buffer_offset,
3448                        );
3449                        assert_eq!(
3450                            right_offset,
3451                            excerpt_start.bytes + (buffer_right_offset - buffer_range.start),
3452                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
3453                            offset,
3454                            buffer_id,
3455                            buffer_offset,
3456                        );
3457
3458                        let left_point = snapshot.clip_point(point, Bias::Left);
3459                        let right_point = snapshot.clip_point(point, Bias::Right);
3460                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
3461                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
3462                        assert_eq!(
3463                            left_point,
3464                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
3465                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
3466                            point,
3467                            buffer_id,
3468                            buffer_point,
3469                        );
3470                        assert_eq!(
3471                            right_point,
3472                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
3473                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
3474                            point,
3475                            buffer_id,
3476                            buffer_point,
3477                        );
3478
3479                        assert_eq!(
3480                            snapshot.point_to_offset(left_point),
3481                            left_offset,
3482                            "point_to_offset({:?})",
3483                            left_point,
3484                        );
3485                        assert_eq!(
3486                            snapshot.offset_to_point(left_offset),
3487                            left_point,
3488                            "offset_to_point({:?})",
3489                            left_offset,
3490                        );
3491
3492                        offset += 1;
3493                        buffer_offset += 1;
3494                        if ch == '\n' {
3495                            point += Point::new(1, 0);
3496                            buffer_point += Point::new(1, 0);
3497                        } else {
3498                            point += Point::new(0, 1);
3499                            buffer_point += Point::new(0, 1);
3500                        }
3501                    }
3502
3503                    for _ in 0..ch.len_utf16() {
3504                        let left_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Left);
3505                        let right_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Right);
3506                        let buffer_left_point_utf16 =
3507                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Left);
3508                        let buffer_right_point_utf16 =
3509                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Right);
3510                        assert_eq!(
3511                            left_point_utf16,
3512                            excerpt_start.lines_utf16
3513                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
3514                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
3515                            point_utf16,
3516                            buffer_id,
3517                            buffer_point_utf16,
3518                        );
3519                        assert_eq!(
3520                            right_point_utf16,
3521                            excerpt_start.lines_utf16
3522                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
3523                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
3524                            point_utf16,
3525                            buffer_id,
3526                            buffer_point_utf16,
3527                        );
3528
3529                        if ch == '\n' {
3530                            point_utf16 += PointUtf16::new(1, 0);
3531                            buffer_point_utf16 += PointUtf16::new(1, 0);
3532                        } else {
3533                            point_utf16 += PointUtf16::new(0, 1);
3534                            buffer_point_utf16 += PointUtf16::new(0, 1);
3535                        }
3536                    }
3537                }
3538            }
3539
3540            for (row, line) in expected_text.split('\n').enumerate() {
3541                assert_eq!(
3542                    snapshot.line_len(row as u32),
3543                    line.len() as u32,
3544                    "line_len({}).",
3545                    row
3546                );
3547            }
3548
3549            let text_rope = Rope::from(expected_text.as_str());
3550            for _ in 0..10 {
3551                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3552                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3553
3554                let text_for_range = snapshot
3555                    .text_for_range(start_ix..end_ix)
3556                    .collect::<String>();
3557                assert_eq!(
3558                    text_for_range,
3559                    &expected_text[start_ix..end_ix],
3560                    "incorrect text for range {:?}",
3561                    start_ix..end_ix
3562                );
3563
3564                let excerpted_buffer_ranges = multibuffer
3565                    .read(cx)
3566                    .range_to_buffer_ranges(start_ix..end_ix, cx);
3567                let excerpted_buffers_text = excerpted_buffer_ranges
3568                    .into_iter()
3569                    .map(|(buffer, buffer_range)| {
3570                        buffer
3571                            .read(cx)
3572                            .text_for_range(buffer_range)
3573                            .collect::<String>()
3574                    })
3575                    .collect::<Vec<_>>()
3576                    .join("\n");
3577                assert_eq!(excerpted_buffers_text, text_for_range);
3578
3579                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
3580                assert_eq!(
3581                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
3582                    expected_summary,
3583                    "incorrect summary for range {:?}",
3584                    start_ix..end_ix
3585                );
3586            }
3587
3588            // Anchor resolution
3589            for (anchor, resolved_offset) in anchors
3590                .iter()
3591                .zip(snapshot.summaries_for_anchors::<usize, _>(&anchors))
3592            {
3593                assert!(resolved_offset <= snapshot.len());
3594                assert_eq!(
3595                    snapshot.summary_for_anchor::<usize>(anchor),
3596                    resolved_offset
3597                );
3598            }
3599
3600            for _ in 0..10 {
3601                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3602                assert_eq!(
3603                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
3604                    expected_text[..end_ix].chars().rev().collect::<String>(),
3605                );
3606            }
3607
3608            for _ in 0..10 {
3609                let end_ix = rng.gen_range(0..=text_rope.len());
3610                let start_ix = rng.gen_range(0..=end_ix);
3611                assert_eq!(
3612                    snapshot
3613                        .bytes_in_range(start_ix..end_ix)
3614                        .flatten()
3615                        .copied()
3616                        .collect::<Vec<_>>(),
3617                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
3618                    "bytes_in_range({:?})",
3619                    start_ix..end_ix,
3620                );
3621            }
3622        }
3623
3624        let snapshot = multibuffer.read(cx).snapshot(cx);
3625        for (old_snapshot, subscription) in old_versions {
3626            let edits = subscription.consume().into_inner();
3627
3628            log::info!(
3629                "applying subscription edits to old text: {:?}: {:?}",
3630                old_snapshot.text(),
3631                edits,
3632            );
3633
3634            let mut text = old_snapshot.text();
3635            for edit in edits {
3636                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
3637                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
3638            }
3639            assert_eq!(text.to_string(), snapshot.text());
3640        }
3641    }
3642
3643    #[gpui::test]
3644    fn test_history(cx: &mut MutableAppContext) {
3645        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "1234", cx));
3646        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "5678", cx));
3647        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3648        let group_interval = multibuffer.read(cx).history.group_interval;
3649        multibuffer.update(cx, |multibuffer, cx| {
3650            multibuffer.push_excerpts(buffer_1.clone(), [0..buffer_1.read(cx).len()], cx);
3651            multibuffer.push_excerpts(buffer_2.clone(), [0..buffer_2.read(cx).len()], cx);
3652        });
3653
3654        let mut now = Instant::now();
3655
3656        multibuffer.update(cx, |multibuffer, cx| {
3657            multibuffer.start_transaction_at(now, cx);
3658            multibuffer.edit(
3659                [
3660                    Point::new(0, 0)..Point::new(0, 0),
3661                    Point::new(1, 0)..Point::new(1, 0),
3662                ],
3663                "A",
3664                cx,
3665            );
3666            multibuffer.edit(
3667                [
3668                    Point::new(0, 1)..Point::new(0, 1),
3669                    Point::new(1, 1)..Point::new(1, 1),
3670                ],
3671                "B",
3672                cx,
3673            );
3674            multibuffer.end_transaction_at(now, cx);
3675            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3676
3677            now += 2 * group_interval;
3678            multibuffer.start_transaction_at(now, cx);
3679            multibuffer.edit([2..2], "C", cx);
3680            multibuffer.end_transaction_at(now, cx);
3681            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3682
3683            multibuffer.undo(cx);
3684            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3685
3686            multibuffer.undo(cx);
3687            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3688
3689            multibuffer.redo(cx);
3690            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3691
3692            multibuffer.redo(cx);
3693            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3694
3695            buffer_1.update(cx, |buffer_1, cx| buffer_1.undo(cx));
3696            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3697
3698            multibuffer.undo(cx);
3699            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
3700
3701            multibuffer.redo(cx);
3702            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3703
3704            multibuffer.redo(cx);
3705            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3706
3707            multibuffer.undo(cx);
3708            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
3709
3710            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
3711            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
3712
3713            multibuffer.undo(cx);
3714            assert_eq!(multibuffer.read(cx).text(), "C1234\n5678");
3715        });
3716    }
3717}