1mod anchor;
   2
   3pub use anchor::{Anchor, AnchorRangeExt};
   4use anyhow::Result;
   5use clock::ReplicaId;
   6use collections::{Bound, HashMap, HashSet};
   7use gpui::{AppContext, Entity, ModelContext, ModelHandle, Task};
   8pub use language::Completion;
   9use language::{
  10    char_kind, Buffer, BufferChunks, BufferSnapshot, CharKind, Chunk, DiagnosticEntry, Event, File,
  11    IndentSize, Language, OffsetRangeExt, Outline, OutlineItem, Selection, ToOffset as _,
  12    ToPoint as _, ToPointUtf16 as _, TransactionId,
  13};
  14use settings::Settings;
  15use smallvec::SmallVec;
  16use std::{
  17    cell::{Ref, RefCell},
  18    cmp, fmt, io,
  19    iter::{self, FromIterator},
  20    mem,
  21    ops::{Range, RangeBounds, Sub},
  22    str,
  23    sync::Arc,
  24    time::{Duration, Instant},
  25};
  26use sum_tree::{Bias, Cursor, SumTree};
  27use text::{
  28    locator::Locator,
  29    rope::TextDimension,
  30    subscription::{Subscription, Topic},
  31    Edit, Point, PointUtf16, TextSummary,
  32};
  33use theme::SyntaxTheme;
  34use util::post_inc;
  35
  36const NEWLINES: &'static [u8] = &[b'\n'; u8::MAX as usize];
  37
  38pub type ExcerptId = Locator;
  39
  40pub struct MultiBuffer {
  41    snapshot: RefCell<MultiBufferSnapshot>,
  42    buffers: RefCell<HashMap<usize, BufferState>>,
  43    used_excerpt_ids: SumTree<ExcerptId>,
  44    next_excerpt_key: usize,
  45    subscriptions: Topic,
  46    singleton: bool,
  47    replica_id: ReplicaId,
  48    history: History,
  49    title: Option<String>,
  50}
  51
  52#[derive(Clone)]
  53struct History {
  54    next_transaction_id: TransactionId,
  55    undo_stack: Vec<Transaction>,
  56    redo_stack: Vec<Transaction>,
  57    transaction_depth: usize,
  58    group_interval: Duration,
  59}
  60
  61#[derive(Clone)]
  62struct Transaction {
  63    id: TransactionId,
  64    buffer_transactions: HashMap<usize, text::TransactionId>,
  65    first_edit_at: Instant,
  66    last_edit_at: Instant,
  67    suppress_grouping: bool,
  68}
  69
  70pub trait ToOffset: 'static + fmt::Debug {
  71    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
  72}
  73
  74pub trait ToPoint: 'static + fmt::Debug {
  75    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
  76}
  77
  78pub trait ToPointUtf16: 'static + fmt::Debug {
  79    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
  80}
  81
  82struct BufferState {
  83    buffer: ModelHandle<Buffer>,
  84    last_version: clock::Global,
  85    last_parse_count: usize,
  86    last_selections_update_count: usize,
  87    last_diagnostics_update_count: usize,
  88    last_file_update_count: usize,
  89    excerpts: Vec<ExcerptId>,
  90    _subscriptions: [gpui::Subscription; 2],
  91}
  92
  93#[derive(Clone, Default)]
  94pub struct MultiBufferSnapshot {
  95    singleton: bool,
  96    excerpts: SumTree<Excerpt>,
  97    parse_count: usize,
  98    diagnostics_update_count: usize,
  99    trailing_excerpt_update_count: usize,
 100    edit_count: usize,
 101    is_dirty: bool,
 102    has_conflict: bool,
 103}
 104
 105pub struct ExcerptBoundary {
 106    pub id: ExcerptId,
 107    pub key: usize,
 108    pub row: u32,
 109    pub buffer: BufferSnapshot,
 110    pub range: ExcerptRange<text::Anchor>,
 111    pub starts_new_buffer: bool,
 112}
 113
 114#[derive(Clone)]
 115struct Excerpt {
 116    id: ExcerptId,
 117    key: usize,
 118    buffer_id: usize,
 119    buffer: BufferSnapshot,
 120    range: ExcerptRange<text::Anchor>,
 121    max_buffer_row: u32,
 122    text_summary: TextSummary,
 123    has_trailing_newline: bool,
 124}
 125
 126#[derive(Clone, Debug, Eq, PartialEq)]
 127pub struct ExcerptRange<T> {
 128    pub context: Range<T>,
 129    pub primary: Option<Range<T>>,
 130}
 131
 132#[derive(Clone, Debug, Default)]
 133struct ExcerptSummary {
 134    excerpt_id: ExcerptId,
 135    max_buffer_row: u32,
 136    text: TextSummary,
 137}
 138
 139pub struct MultiBufferRows<'a> {
 140    buffer_row_range: Range<u32>,
 141    excerpts: Cursor<'a, Excerpt, Point>,
 142}
 143
 144pub struct MultiBufferChunks<'a> {
 145    range: Range<usize>,
 146    excerpts: Cursor<'a, Excerpt, usize>,
 147    excerpt_chunks: Option<ExcerptChunks<'a>>,
 148    language_aware: bool,
 149}
 150
 151pub struct MultiBufferBytes<'a> {
 152    range: Range<usize>,
 153    excerpts: Cursor<'a, Excerpt, usize>,
 154    excerpt_bytes: Option<ExcerptBytes<'a>>,
 155    chunk: &'a [u8],
 156}
 157
 158struct ExcerptChunks<'a> {
 159    content_chunks: BufferChunks<'a>,
 160    footer_height: usize,
 161}
 162
 163struct ExcerptBytes<'a> {
 164    content_bytes: language::rope::Bytes<'a>,
 165    footer_height: usize,
 166}
 167
 168impl MultiBuffer {
 169    pub fn new(replica_id: ReplicaId) -> Self {
 170        Self {
 171            snapshot: Default::default(),
 172            buffers: Default::default(),
 173            used_excerpt_ids: Default::default(),
 174            next_excerpt_key: Default::default(),
 175            subscriptions: Default::default(),
 176            singleton: false,
 177            replica_id,
 178            history: History {
 179                next_transaction_id: Default::default(),
 180                undo_stack: Default::default(),
 181                redo_stack: Default::default(),
 182                transaction_depth: 0,
 183                group_interval: Duration::from_millis(300),
 184            },
 185            title: Default::default(),
 186        }
 187    }
 188
 189    pub fn clone(&self, new_cx: &mut ModelContext<Self>) -> Self {
 190        let mut buffers = HashMap::default();
 191        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 192            buffers.insert(
 193                *buffer_id,
 194                BufferState {
 195                    buffer: buffer_state.buffer.clone(),
 196                    last_version: buffer_state.last_version.clone(),
 197                    last_parse_count: buffer_state.last_parse_count,
 198                    last_selections_update_count: buffer_state.last_selections_update_count,
 199                    last_diagnostics_update_count: buffer_state.last_diagnostics_update_count,
 200                    last_file_update_count: buffer_state.last_file_update_count,
 201                    excerpts: buffer_state.excerpts.clone(),
 202                    _subscriptions: [
 203                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 204                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 205                    ],
 206                },
 207            );
 208        }
 209        Self {
 210            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 211            buffers: RefCell::new(buffers),
 212            used_excerpt_ids: self.used_excerpt_ids.clone(),
 213            next_excerpt_key: self.next_excerpt_key,
 214            subscriptions: Default::default(),
 215            singleton: self.singleton,
 216            replica_id: self.replica_id,
 217            history: self.history.clone(),
 218            title: self.title.clone(),
 219        }
 220    }
 221
 222    pub fn with_title(mut self, title: String) -> Self {
 223        self.title = Some(title);
 224        self
 225    }
 226
 227    pub fn singleton(buffer: ModelHandle<Buffer>, cx: &mut ModelContext<Self>) -> Self {
 228        let mut this = Self::new(buffer.read(cx).replica_id());
 229        this.singleton = true;
 230        this.push_excerpts(
 231            buffer,
 232            [ExcerptRange {
 233                context: text::Anchor::MIN..text::Anchor::MAX,
 234                primary: None,
 235            }],
 236            cx,
 237        );
 238        this.snapshot.borrow_mut().singleton = true;
 239        this
 240    }
 241
 242    pub fn replica_id(&self) -> ReplicaId {
 243        self.replica_id
 244    }
 245
 246    pub fn snapshot(&self, cx: &AppContext) -> MultiBufferSnapshot {
 247        self.sync(cx);
 248        self.snapshot.borrow().clone()
 249    }
 250
 251    pub(crate) fn read(&self, cx: &AppContext) -> Ref<MultiBufferSnapshot> {
 252        self.sync(cx);
 253        self.snapshot.borrow()
 254    }
 255
 256    pub fn as_singleton(&self) -> Option<ModelHandle<Buffer>> {
 257        if self.singleton {
 258            return Some(
 259                self.buffers
 260                    .borrow()
 261                    .values()
 262                    .next()
 263                    .unwrap()
 264                    .buffer
 265                    .clone(),
 266            );
 267        } else {
 268            None
 269        }
 270    }
 271
 272    pub fn is_singleton(&self) -> bool {
 273        self.singleton
 274    }
 275
 276    pub fn subscribe(&mut self) -> Subscription {
 277        self.subscriptions.subscribe()
 278    }
 279
 280    pub fn is_dirty(&self, cx: &AppContext) -> bool {
 281        self.read(cx).is_dirty()
 282    }
 283
 284    pub fn has_conflict(&self, cx: &AppContext) -> bool {
 285        self.read(cx).has_conflict()
 286    }
 287
 288    pub fn len(&self, cx: &AppContext) -> usize {
 289        self.read(cx).len()
 290    }
 291
 292    pub fn symbols_containing<T: ToOffset>(
 293        &self,
 294        offset: T,
 295        theme: Option<&SyntaxTheme>,
 296        cx: &AppContext,
 297    ) -> Option<(usize, Vec<OutlineItem<Anchor>>)> {
 298        self.read(cx).symbols_containing(offset, theme)
 299    }
 300
 301    pub fn edit<I, S, T>(&mut self, edits: I, cx: &mut ModelContext<Self>)
 302    where
 303        I: IntoIterator<Item = (Range<S>, T)>,
 304        S: ToOffset,
 305        T: Into<Arc<str>>,
 306    {
 307        self.edit_internal(edits, false, cx)
 308    }
 309
 310    pub fn edit_with_autoindent<I, S, T>(&mut self, edits: I, cx: &mut ModelContext<Self>)
 311    where
 312        I: IntoIterator<Item = (Range<S>, T)>,
 313        S: ToOffset,
 314        T: Into<Arc<str>>,
 315    {
 316        self.edit_internal(edits, true, cx)
 317    }
 318
 319    pub fn edit_internal<I, S, T>(
 320        &mut self,
 321        edits: I,
 322        autoindent: bool,
 323        cx: &mut ModelContext<Self>,
 324    ) where
 325        I: IntoIterator<Item = (Range<S>, T)>,
 326        S: ToOffset,
 327        T: Into<Arc<str>>,
 328    {
 329        if self.buffers.borrow().is_empty() {
 330            return;
 331        }
 332
 333        let snapshot = self.read(cx);
 334        let edits = edits.into_iter().map(|(range, new_text)| {
 335            let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 336            if range.start > range.end {
 337                mem::swap(&mut range.start, &mut range.end);
 338            }
 339            (range, new_text)
 340        });
 341
 342        if let Some(buffer) = self.as_singleton() {
 343            return buffer.update(cx, |buffer, cx| {
 344                if autoindent {
 345                    let language_name = buffer.language().map(|language| language.name());
 346                    let settings = cx.global::<Settings>();
 347                    let indent_size = if settings.hard_tabs(language_name.as_deref()) {
 348                        IndentSize::tab()
 349                    } else {
 350                        IndentSize::spaces(settings.tab_size(language_name.as_deref()))
 351                    };
 352                    buffer.edit_with_autoindent(edits, indent_size, cx);
 353                } else {
 354                    buffer.edit(edits, cx);
 355                }
 356            });
 357        }
 358
 359        let mut buffer_edits: HashMap<usize, Vec<(Range<usize>, Arc<str>, bool)>> =
 360            Default::default();
 361        let mut cursor = snapshot.excerpts.cursor::<usize>();
 362        for (range, new_text) in edits {
 363            let new_text: Arc<str> = new_text.into();
 364            cursor.seek(&range.start, Bias::Right, &());
 365            if cursor.item().is_none() && range.start == *cursor.start() {
 366                cursor.prev(&());
 367            }
 368            let start_excerpt = cursor.item().expect("start offset out of bounds");
 369            let start_overshoot = range.start - cursor.start();
 370            let buffer_start = start_excerpt
 371                .range
 372                .context
 373                .start
 374                .to_offset(&start_excerpt.buffer)
 375                + start_overshoot;
 376
 377            cursor.seek(&range.end, Bias::Right, &());
 378            if cursor.item().is_none() && range.end == *cursor.start() {
 379                cursor.prev(&());
 380            }
 381            let end_excerpt = cursor.item().expect("end offset out of bounds");
 382            let end_overshoot = range.end - cursor.start();
 383            let buffer_end = end_excerpt
 384                .range
 385                .context
 386                .start
 387                .to_offset(&end_excerpt.buffer)
 388                + end_overshoot;
 389
 390            if start_excerpt.id == end_excerpt.id {
 391                buffer_edits
 392                    .entry(start_excerpt.buffer_id)
 393                    .or_insert(Vec::new())
 394                    .push((buffer_start..buffer_end, new_text, true));
 395            } else {
 396                let start_excerpt_range = buffer_start
 397                    ..start_excerpt
 398                        .range
 399                        .context
 400                        .end
 401                        .to_offset(&start_excerpt.buffer);
 402                let end_excerpt_range = end_excerpt
 403                    .range
 404                    .context
 405                    .start
 406                    .to_offset(&end_excerpt.buffer)
 407                    ..buffer_end;
 408                buffer_edits
 409                    .entry(start_excerpt.buffer_id)
 410                    .or_insert(Vec::new())
 411                    .push((start_excerpt_range, new_text.clone(), true));
 412                buffer_edits
 413                    .entry(end_excerpt.buffer_id)
 414                    .or_insert(Vec::new())
 415                    .push((end_excerpt_range, new_text.clone(), false));
 416
 417                cursor.seek(&range.start, Bias::Right, &());
 418                cursor.next(&());
 419                while let Some(excerpt) = cursor.item() {
 420                    if excerpt.id == end_excerpt.id {
 421                        break;
 422                    }
 423                    buffer_edits
 424                        .entry(excerpt.buffer_id)
 425                        .or_insert(Vec::new())
 426                        .push((
 427                            excerpt.range.context.to_offset(&excerpt.buffer),
 428                            new_text.clone(),
 429                            false,
 430                        ));
 431                    cursor.next(&());
 432                }
 433            }
 434        }
 435
 436        for (buffer_id, mut edits) in buffer_edits {
 437            edits.sort_unstable_by_key(|(range, _, _)| range.start);
 438            self.buffers.borrow()[&buffer_id]
 439                .buffer
 440                .update(cx, |buffer, cx| {
 441                    let mut edits = edits.into_iter().peekable();
 442                    let mut insertions = Vec::new();
 443                    let mut deletions = Vec::new();
 444                    let empty_str: Arc<str> = "".into();
 445                    while let Some((mut range, new_text, mut is_insertion)) = edits.next() {
 446                        while let Some((next_range, _, next_is_insertion)) = edits.peek() {
 447                            if range.end >= next_range.start {
 448                                range.end = cmp::max(next_range.end, range.end);
 449
 450                                is_insertion |= *next_is_insertion;
 451                                edits.next();
 452                            } else {
 453                                break;
 454                            }
 455                        }
 456
 457                        if is_insertion {
 458                            insertions.push((
 459                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 460                                new_text.clone(),
 461                            ));
 462                        } else if !range.is_empty() {
 463                            deletions.push((
 464                                buffer.anchor_before(range.start)..buffer.anchor_before(range.end),
 465                                empty_str.clone(),
 466                            ));
 467                        }
 468                    }
 469                    let language_name = buffer.language().map(|l| l.name());
 470
 471                    if autoindent {
 472                        let settings = cx.global::<Settings>();
 473                        let indent_size = if settings.hard_tabs(language_name.as_deref()) {
 474                            IndentSize::tab()
 475                        } else {
 476                            IndentSize::spaces(settings.tab_size(language_name.as_deref()))
 477                        };
 478
 479                        buffer.edit_with_autoindent(deletions, indent_size, cx);
 480                        buffer.edit_with_autoindent(insertions, indent_size, cx);
 481                    } else {
 482                        buffer.edit(deletions, cx);
 483                        buffer.edit(insertions, cx);
 484                    }
 485                })
 486        }
 487    }
 488
 489    pub fn start_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 490        self.start_transaction_at(Instant::now(), cx)
 491    }
 492
 493    pub(crate) fn start_transaction_at(
 494        &mut self,
 495        now: Instant,
 496        cx: &mut ModelContext<Self>,
 497    ) -> Option<TransactionId> {
 498        if let Some(buffer) = self.as_singleton() {
 499            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 500        }
 501
 502        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 503            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
 504        }
 505        self.history.start_transaction(now)
 506    }
 507
 508    pub fn end_transaction(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 509        self.end_transaction_at(Instant::now(), cx)
 510    }
 511
 512    pub(crate) fn end_transaction_at(
 513        &mut self,
 514        now: Instant,
 515        cx: &mut ModelContext<Self>,
 516    ) -> Option<TransactionId> {
 517        if let Some(buffer) = self.as_singleton() {
 518            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
 519        }
 520
 521        let mut buffer_transactions = HashMap::default();
 522        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 523            if let Some(transaction_id) =
 524                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
 525            {
 526                buffer_transactions.insert(buffer.id(), transaction_id);
 527            }
 528        }
 529
 530        if self.history.end_transaction(now, buffer_transactions) {
 531            let transaction_id = self.history.group().unwrap();
 532            Some(transaction_id)
 533        } else {
 534            None
 535        }
 536    }
 537
 538    pub fn finalize_last_transaction(&mut self, cx: &mut ModelContext<Self>) {
 539        self.history.finalize_last_transaction();
 540        for BufferState { buffer, .. } in self.buffers.borrow().values() {
 541            buffer.update(cx, |buffer, _| {
 542                buffer.finalize_last_transaction();
 543            });
 544        }
 545    }
 546
 547    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T)
 548    where
 549        T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
 550    {
 551        self.history
 552            .push_transaction(buffer_transactions, Instant::now());
 553        self.history.finalize_last_transaction();
 554    }
 555
 556    pub fn set_active_selections(
 557        &mut self,
 558        selections: &[Selection<Anchor>],
 559        line_mode: bool,
 560        cx: &mut ModelContext<Self>,
 561    ) {
 562        let mut selections_by_buffer: HashMap<usize, Vec<Selection<text::Anchor>>> =
 563            Default::default();
 564        let snapshot = self.read(cx);
 565        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 566        for selection in selections {
 567            cursor.seek(&Some(&selection.start.excerpt_id), Bias::Left, &());
 568            while let Some(excerpt) = cursor.item() {
 569                if excerpt.id > selection.end.excerpt_id {
 570                    break;
 571                }
 572
 573                let mut start = excerpt.range.context.start.clone();
 574                let mut end = excerpt.range.context.end.clone();
 575                if excerpt.id == selection.start.excerpt_id {
 576                    start = selection.start.text_anchor.clone();
 577                }
 578                if excerpt.id == selection.end.excerpt_id {
 579                    end = selection.end.text_anchor.clone();
 580                }
 581                selections_by_buffer
 582                    .entry(excerpt.buffer_id)
 583                    .or_default()
 584                    .push(Selection {
 585                        id: selection.id,
 586                        start,
 587                        end,
 588                        reversed: selection.reversed,
 589                        goal: selection.goal,
 590                    });
 591
 592                cursor.next(&());
 593            }
 594        }
 595
 596        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 597            if !selections_by_buffer.contains_key(buffer_id) {
 598                buffer_state
 599                    .buffer
 600                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 601            }
 602        }
 603
 604        for (buffer_id, mut selections) in selections_by_buffer {
 605            self.buffers.borrow()[&buffer_id]
 606                .buffer
 607                .update(cx, |buffer, cx| {
 608                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
 609                    let mut selections = selections.into_iter().peekable();
 610                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
 611                        let mut selection = selections.next()?;
 612                        while let Some(next_selection) = selections.peek() {
 613                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
 614                                let next_selection = selections.next().unwrap();
 615                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
 616                                    selection.end = next_selection.end;
 617                                }
 618                            } else {
 619                                break;
 620                            }
 621                        }
 622                        Some(selection)
 623                    }));
 624                    buffer.set_active_selections(merged_selections, line_mode, cx);
 625                });
 626        }
 627    }
 628
 629    pub fn remove_active_selections(&mut self, cx: &mut ModelContext<Self>) {
 630        for buffer in self.buffers.borrow().values() {
 631            buffer
 632                .buffer
 633                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
 634        }
 635    }
 636
 637    pub fn undo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 638        if let Some(buffer) = self.as_singleton() {
 639            return buffer.update(cx, |buffer, cx| buffer.undo(cx));
 640        }
 641
 642        while let Some(transaction) = self.history.pop_undo() {
 643            let mut undone = false;
 644            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 645                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 646                    undone |= buffer.update(cx, |buffer, cx| {
 647                        let undo_to = *buffer_transaction_id;
 648                        if let Some(entry) = buffer.peek_undo_stack() {
 649                            *buffer_transaction_id = entry.transaction_id();
 650                        }
 651                        buffer.undo_to_transaction(undo_to, cx)
 652                    });
 653                }
 654            }
 655
 656            if undone {
 657                return Some(transaction.id);
 658            }
 659        }
 660
 661        None
 662    }
 663
 664    pub fn redo(&mut self, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
 665        if let Some(buffer) = self.as_singleton() {
 666            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
 667        }
 668
 669        while let Some(transaction) = self.history.pop_redo() {
 670            let mut redone = false;
 671            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
 672                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(&buffer_id) {
 673                    redone |= buffer.update(cx, |buffer, cx| {
 674                        let redo_to = *buffer_transaction_id;
 675                        if let Some(entry) = buffer.peek_redo_stack() {
 676                            *buffer_transaction_id = entry.transaction_id();
 677                        }
 678                        buffer.redo_to_transaction(redo_to, cx)
 679                    });
 680                }
 681            }
 682
 683            if redone {
 684                return Some(transaction.id);
 685            }
 686        }
 687
 688        None
 689    }
 690
 691    pub fn push_excerpts<O>(
 692        &mut self,
 693        buffer: ModelHandle<Buffer>,
 694        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
 695        cx: &mut ModelContext<Self>,
 696    ) -> Vec<ExcerptId>
 697    where
 698        O: text::ToOffset,
 699    {
 700        self.insert_excerpts_after(&ExcerptId::max(), buffer, ranges, cx)
 701    }
 702
 703    pub fn push_excerpts_with_context_lines<O>(
 704        &mut self,
 705        buffer: ModelHandle<Buffer>,
 706        ranges: Vec<Range<O>>,
 707        context_line_count: u32,
 708        cx: &mut ModelContext<Self>,
 709    ) -> Vec<Range<Anchor>>
 710    where
 711        O: text::ToPoint + text::ToOffset,
 712    {
 713        let buffer_id = buffer.id();
 714        let buffer_snapshot = buffer.read(cx).snapshot();
 715        let max_point = buffer_snapshot.max_point();
 716
 717        let mut range_counts = Vec::new();
 718        let mut excerpt_ranges = Vec::new();
 719        let mut range_iter = ranges
 720            .iter()
 721            .map(|range| {
 722                range.start.to_point(&buffer_snapshot)..range.end.to_point(&buffer_snapshot)
 723            })
 724            .peekable();
 725        while let Some(range) = range_iter.next() {
 726            let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
 727            let mut excerpt_end =
 728                Point::new(range.end.row + 1 + context_line_count, 0).min(max_point);
 729            let mut ranges_in_excerpt = 1;
 730
 731            while let Some(next_range) = range_iter.peek() {
 732                if next_range.start.row <= excerpt_end.row + context_line_count {
 733                    excerpt_end =
 734                        Point::new(next_range.end.row + 1 + context_line_count, 0).min(max_point);
 735                    ranges_in_excerpt += 1;
 736                    range_iter.next();
 737                } else {
 738                    break;
 739                }
 740            }
 741
 742            excerpt_ranges.push(ExcerptRange {
 743                context: excerpt_start..excerpt_end,
 744                primary: Some(range),
 745            });
 746            range_counts.push(ranges_in_excerpt);
 747        }
 748
 749        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
 750
 751        let mut anchor_ranges = Vec::new();
 752        let mut ranges = ranges.into_iter();
 753        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
 754            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
 755                let start = Anchor {
 756                    buffer_id: Some(buffer_id),
 757                    excerpt_id: excerpt_id.clone(),
 758                    text_anchor: buffer_snapshot.anchor_after(range.start),
 759                };
 760                let end = Anchor {
 761                    buffer_id: Some(buffer_id),
 762                    excerpt_id: excerpt_id.clone(),
 763                    text_anchor: buffer_snapshot.anchor_after(range.end),
 764                };
 765                start..end
 766            }))
 767        }
 768        anchor_ranges
 769    }
 770
 771    pub fn insert_excerpts_after<O>(
 772        &mut self,
 773        prev_excerpt_id: &ExcerptId,
 774        buffer: ModelHandle<Buffer>,
 775        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
 776        cx: &mut ModelContext<Self>,
 777    ) -> Vec<ExcerptId>
 778    where
 779        O: text::ToOffset,
 780    {
 781        assert_eq!(self.history.transaction_depth, 0);
 782        let mut ranges = ranges.into_iter().peekable();
 783        if ranges.peek().is_none() {
 784            return Default::default();
 785        }
 786
 787        self.sync(cx);
 788
 789        let buffer_id = buffer.id();
 790        let buffer_snapshot = buffer.read(cx).snapshot();
 791
 792        let mut buffers = self.buffers.borrow_mut();
 793        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| BufferState {
 794            last_version: buffer_snapshot.version().clone(),
 795            last_parse_count: buffer_snapshot.parse_count(),
 796            last_selections_update_count: buffer_snapshot.selections_update_count(),
 797            last_diagnostics_update_count: buffer_snapshot.diagnostics_update_count(),
 798            last_file_update_count: buffer_snapshot.file_update_count(),
 799            excerpts: Default::default(),
 800            _subscriptions: [
 801                cx.observe(&buffer, |_, _, cx| cx.notify()),
 802                cx.subscribe(&buffer, Self::on_buffer_event),
 803            ],
 804            buffer,
 805        });
 806
 807        let mut snapshot = self.snapshot.borrow_mut();
 808        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 809        let mut new_excerpts = cursor.slice(&Some(prev_excerpt_id), Bias::Right, &());
 810
 811        let edit_start = new_excerpts.summary().text.bytes;
 812        new_excerpts.update_last(
 813            |excerpt| {
 814                excerpt.has_trailing_newline = true;
 815            },
 816            &(),
 817        );
 818
 819        let mut used_cursor = self.used_excerpt_ids.cursor::<Locator>();
 820        used_cursor.seek(prev_excerpt_id, Bias::Right, &());
 821        let mut prev_id = if let Some(excerpt_id) = used_cursor.prev_item() {
 822            excerpt_id.clone()
 823        } else {
 824            ExcerptId::min()
 825        };
 826        let next_id = if let Some(excerpt_id) = used_cursor.item() {
 827            excerpt_id.clone()
 828        } else {
 829            ExcerptId::max()
 830        };
 831        drop(used_cursor);
 832
 833        let mut ids = Vec::new();
 834        while let Some(range) = ranges.next() {
 835            let id = ExcerptId::between(&prev_id, &next_id);
 836            if let Err(ix) = buffer_state.excerpts.binary_search(&id) {
 837                buffer_state.excerpts.insert(ix, id.clone());
 838            }
 839            let range = ExcerptRange {
 840                context: buffer_snapshot.anchor_before(&range.context.start)
 841                    ..buffer_snapshot.anchor_after(&range.context.end),
 842                primary: range.primary.map(|primary| {
 843                    buffer_snapshot.anchor_before(&primary.start)
 844                        ..buffer_snapshot.anchor_after(&primary.end)
 845                }),
 846            };
 847            let excerpt = Excerpt::new(
 848                id.clone(),
 849                post_inc(&mut self.next_excerpt_key),
 850                buffer_id,
 851                buffer_snapshot.clone(),
 852                range,
 853                ranges.peek().is_some() || cursor.item().is_some(),
 854            );
 855            new_excerpts.push(excerpt, &());
 856            prev_id = id.clone();
 857            ids.push(id);
 858        }
 859        self.used_excerpt_ids.edit(
 860            ids.iter().cloned().map(sum_tree::Edit::Insert).collect(),
 861            &(),
 862        );
 863
 864        let edit_end = new_excerpts.summary().text.bytes;
 865
 866        let suffix = cursor.suffix(&());
 867        let changed_trailing_excerpt = suffix.is_empty();
 868        new_excerpts.push_tree(suffix, &());
 869        drop(cursor);
 870        snapshot.excerpts = new_excerpts;
 871        if changed_trailing_excerpt {
 872            snapshot.trailing_excerpt_update_count += 1;
 873        }
 874
 875        self.subscriptions.publish_mut([Edit {
 876            old: edit_start..edit_start,
 877            new: edit_start..edit_end,
 878        }]);
 879        cx.emit(Event::Edited);
 880        cx.notify();
 881        ids
 882    }
 883
 884    pub fn clear(&mut self, cx: &mut ModelContext<Self>) {
 885        self.sync(cx);
 886        self.buffers.borrow_mut().clear();
 887        let mut snapshot = self.snapshot.borrow_mut();
 888        let prev_len = snapshot.len();
 889        snapshot.excerpts = Default::default();
 890        snapshot.trailing_excerpt_update_count += 1;
 891        snapshot.is_dirty = false;
 892        snapshot.has_conflict = false;
 893
 894        self.subscriptions.publish_mut([Edit {
 895            old: 0..prev_len,
 896            new: 0..0,
 897        }]);
 898        cx.emit(Event::Edited);
 899        cx.notify();
 900    }
 901
 902    pub fn excerpts_for_buffer(
 903        &self,
 904        buffer: &ModelHandle<Buffer>,
 905        cx: &AppContext,
 906    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
 907        let mut excerpts = Vec::new();
 908        let snapshot = self.read(cx);
 909        let buffers = self.buffers.borrow();
 910        let mut cursor = snapshot.excerpts.cursor::<Option<&ExcerptId>>();
 911        for excerpt_id in buffers
 912            .get(&buffer.id())
 913            .map(|state| &state.excerpts)
 914            .into_iter()
 915            .flatten()
 916        {
 917            cursor.seek_forward(&Some(excerpt_id), Bias::Left, &());
 918            if let Some(excerpt) = cursor.item() {
 919                if excerpt.id == *excerpt_id {
 920                    excerpts.push((excerpt.id.clone(), excerpt.range.clone()));
 921                }
 922            }
 923        }
 924
 925        excerpts
 926    }
 927
 928    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
 929        self.buffers
 930            .borrow()
 931            .values()
 932            .flat_map(|state| state.excerpts.iter().cloned())
 933            .collect()
 934    }
 935
 936    pub fn excerpt_containing(
 937        &self,
 938        position: impl ToOffset,
 939        cx: &AppContext,
 940    ) -> Option<(ModelHandle<Buffer>, Range<text::Anchor>)> {
 941        let snapshot = self.read(cx);
 942        let position = position.to_offset(&snapshot);
 943
 944        let mut cursor = snapshot.excerpts.cursor::<usize>();
 945        cursor.seek(&position, Bias::Right, &());
 946        cursor.item().map(|excerpt| {
 947            (
 948                self.buffers
 949                    .borrow()
 950                    .get(&excerpt.buffer_id)
 951                    .unwrap()
 952                    .buffer
 953                    .clone(),
 954                excerpt.range.context.clone(),
 955            )
 956        })
 957    }
 958
 959    // If point is at the end of the buffer, the last excerpt is returned
 960    pub fn point_to_buffer_offset<'a, T: ToOffset>(
 961        &'a self,
 962        point: T,
 963        cx: &AppContext,
 964    ) -> Option<(ModelHandle<Buffer>, usize)> {
 965        let snapshot = self.read(cx);
 966        let offset = point.to_offset(&snapshot);
 967        let mut cursor = snapshot.excerpts.cursor::<usize>();
 968        cursor.seek(&offset, Bias::Right, &());
 969        if cursor.item().is_none() {
 970            cursor.prev(&());
 971        }
 972
 973        cursor.item().map(|excerpt| {
 974            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
 975            let buffer_point = excerpt_start + offset - *cursor.start();
 976            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
 977
 978            (buffer, buffer_point)
 979        })
 980    }
 981
 982    pub fn range_to_buffer_ranges<'a, T: ToOffset>(
 983        &'a self,
 984        range: Range<T>,
 985        cx: &AppContext,
 986    ) -> Vec<(ModelHandle<Buffer>, Range<usize>)> {
 987        let snapshot = self.read(cx);
 988        let start = range.start.to_offset(&snapshot);
 989        let end = range.end.to_offset(&snapshot);
 990
 991        let mut result = Vec::new();
 992        let mut cursor = snapshot.excerpts.cursor::<usize>();
 993        cursor.seek(&start, Bias::Right, &());
 994        while let Some(excerpt) = cursor.item() {
 995            if *cursor.start() > end {
 996                break;
 997            }
 998
 999            let mut end_before_newline = cursor.end(&());
1000            if excerpt.has_trailing_newline {
1001                end_before_newline -= 1;
1002            }
1003            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1004            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
1005            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
1006            let buffer = self.buffers.borrow()[&excerpt.buffer_id].buffer.clone();
1007            result.push((buffer, start..end));
1008            cursor.next(&());
1009        }
1010
1011        result
1012    }
1013
1014    pub fn remove_excerpts<'a>(
1015        &mut self,
1016        excerpt_ids: impl IntoIterator<Item = &'a ExcerptId>,
1017        cx: &mut ModelContext<Self>,
1018    ) {
1019        self.sync(cx);
1020        let mut buffers = self.buffers.borrow_mut();
1021        let mut snapshot = self.snapshot.borrow_mut();
1022        let mut new_excerpts = SumTree::new();
1023        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
1024        let mut edits = Vec::new();
1025        let mut excerpt_ids = excerpt_ids.into_iter().peekable();
1026
1027        while let Some(mut excerpt_id) = excerpt_ids.next() {
1028            // Seek to the next excerpt to remove, preserving any preceding excerpts.
1029            new_excerpts.push_tree(cursor.slice(&Some(excerpt_id), Bias::Left, &()), &());
1030            if let Some(mut excerpt) = cursor.item() {
1031                if excerpt.id != *excerpt_id {
1032                    continue;
1033                }
1034                let mut old_start = cursor.start().1;
1035
1036                // Skip over the removed excerpt.
1037                loop {
1038                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
1039                        buffer_state.excerpts.retain(|id| id != excerpt_id);
1040                        if buffer_state.excerpts.is_empty() {
1041                            buffers.remove(&excerpt.buffer_id);
1042                        }
1043                    }
1044                    cursor.next(&());
1045
1046                    // Skip over any subsequent excerpts that are also removed.
1047                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
1048                        if let Some(next_excerpt) = cursor.item() {
1049                            if next_excerpt.id == *next_excerpt_id {
1050                                excerpt = next_excerpt;
1051                                excerpt_id = excerpt_ids.next().unwrap();
1052                                continue;
1053                            }
1054                        }
1055                    }
1056
1057                    break;
1058                }
1059
1060                // When removing the last excerpt, remove the trailing newline from
1061                // the previous excerpt.
1062                if cursor.item().is_none() && old_start > 0 {
1063                    old_start -= 1;
1064                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
1065                }
1066
1067                // Push an edit for the removal of this run of excerpts.
1068                let old_end = cursor.start().1;
1069                let new_start = new_excerpts.summary().text.bytes;
1070                edits.push(Edit {
1071                    old: old_start..old_end,
1072                    new: new_start..new_start,
1073                });
1074            }
1075        }
1076        let suffix = cursor.suffix(&());
1077        let changed_trailing_excerpt = suffix.is_empty();
1078        new_excerpts.push_tree(suffix, &());
1079        drop(cursor);
1080        snapshot.excerpts = new_excerpts;
1081        if changed_trailing_excerpt {
1082            snapshot.trailing_excerpt_update_count += 1;
1083        }
1084
1085        self.subscriptions.publish_mut(edits);
1086        cx.emit(Event::Edited);
1087        cx.notify();
1088    }
1089
1090    pub fn text_anchor_for_position<'a, T: ToOffset>(
1091        &'a self,
1092        position: T,
1093        cx: &AppContext,
1094    ) -> Option<(ModelHandle<Buffer>, language::Anchor)> {
1095        let snapshot = self.read(cx);
1096        let anchor = snapshot.anchor_before(position);
1097        let buffer = self
1098            .buffers
1099            .borrow()
1100            .get(&anchor.buffer_id?)?
1101            .buffer
1102            .clone();
1103        Some((buffer, anchor.text_anchor))
1104    }
1105
1106    fn on_buffer_event(
1107        &mut self,
1108        _: ModelHandle<Buffer>,
1109        event: &Event,
1110        cx: &mut ModelContext<Self>,
1111    ) {
1112        cx.emit(event.clone());
1113    }
1114
1115    pub fn all_buffers(&self) -> HashSet<ModelHandle<Buffer>> {
1116        self.buffers
1117            .borrow()
1118            .values()
1119            .map(|state| state.buffer.clone())
1120            .collect()
1121    }
1122
1123    pub fn buffer(&self, buffer_id: usize) -> Option<ModelHandle<Buffer>> {
1124        self.buffers
1125            .borrow()
1126            .get(&buffer_id)
1127            .map(|state| state.buffer.clone())
1128    }
1129
1130    pub fn save(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
1131        let mut save_tasks = Vec::new();
1132        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1133            save_tasks.push(buffer.update(cx, |buffer, cx| buffer.save(cx)));
1134        }
1135
1136        cx.spawn(|_, _| async move {
1137            for save in save_tasks {
1138                save.await?;
1139            }
1140            Ok(())
1141        })
1142    }
1143
1144    pub fn is_completion_trigger<T>(&self, position: T, text: &str, cx: &AppContext) -> bool
1145    where
1146        T: ToOffset,
1147    {
1148        let mut chars = text.chars();
1149        let char = if let Some(char) = chars.next() {
1150            char
1151        } else {
1152            return false;
1153        };
1154        if chars.next().is_some() {
1155            return false;
1156        }
1157
1158        if char.is_alphanumeric() || char == '_' {
1159            return true;
1160        }
1161
1162        let snapshot = self.snapshot(cx);
1163        let anchor = snapshot.anchor_before(position);
1164        anchor
1165            .buffer_id
1166            .and_then(|buffer_id| {
1167                let buffer = self.buffers.borrow().get(&buffer_id)?.buffer.clone();
1168                Some(
1169                    buffer
1170                        .read(cx)
1171                        .completion_triggers()
1172                        .iter()
1173                        .any(|string| string == text),
1174                )
1175            })
1176            .unwrap_or(false)
1177    }
1178
1179    pub fn language_at<'a, T: ToOffset>(
1180        &self,
1181        point: T,
1182        cx: &'a AppContext,
1183    ) -> Option<&'a Arc<Language>> {
1184        self.point_to_buffer_offset(point, cx)
1185            .and_then(|(buffer, _)| buffer.read(cx).language())
1186    }
1187
1188    pub fn files<'a>(&'a self, cx: &'a AppContext) -> SmallVec<[&'a dyn File; 2]> {
1189        let buffers = self.buffers.borrow();
1190        buffers
1191            .values()
1192            .filter_map(|buffer| buffer.buffer.read(cx).file())
1193            .collect()
1194    }
1195
1196    pub fn title(&self, cx: &AppContext) -> String {
1197        if let Some(title) = self.title.clone() {
1198            return title;
1199        }
1200
1201        if let Some(buffer) = self.as_singleton() {
1202            if let Some(file) = buffer.read(cx).file() {
1203                return file.file_name(cx).to_string_lossy().into();
1204            }
1205        }
1206
1207        "untitled".into()
1208    }
1209
1210    #[cfg(test)]
1211    pub fn is_parsing(&self, cx: &AppContext) -> bool {
1212        self.as_singleton().unwrap().read(cx).is_parsing()
1213    }
1214
1215    fn sync(&self, cx: &AppContext) {
1216        let mut snapshot = self.snapshot.borrow_mut();
1217        let mut excerpts_to_edit = Vec::new();
1218        let mut reparsed = false;
1219        let mut diagnostics_updated = false;
1220        let mut is_dirty = false;
1221        let mut has_conflict = false;
1222        let mut edited = false;
1223        let mut buffers = self.buffers.borrow_mut();
1224        for buffer_state in buffers.values_mut() {
1225            let buffer = buffer_state.buffer.read(cx);
1226            let version = buffer.version();
1227            let parse_count = buffer.parse_count();
1228            let selections_update_count = buffer.selections_update_count();
1229            let diagnostics_update_count = buffer.diagnostics_update_count();
1230            let file_update_count = buffer.file_update_count();
1231
1232            let buffer_edited = version.changed_since(&buffer_state.last_version);
1233            let buffer_reparsed = parse_count > buffer_state.last_parse_count;
1234            let buffer_selections_updated =
1235                selections_update_count > buffer_state.last_selections_update_count;
1236            let buffer_diagnostics_updated =
1237                diagnostics_update_count > buffer_state.last_diagnostics_update_count;
1238            let buffer_file_updated = file_update_count > buffer_state.last_file_update_count;
1239            if buffer_edited
1240                || buffer_reparsed
1241                || buffer_selections_updated
1242                || buffer_diagnostics_updated
1243                || buffer_file_updated
1244            {
1245                buffer_state.last_version = version;
1246                buffer_state.last_parse_count = parse_count;
1247                buffer_state.last_selections_update_count = selections_update_count;
1248                buffer_state.last_diagnostics_update_count = diagnostics_update_count;
1249                buffer_state.last_file_update_count = file_update_count;
1250                excerpts_to_edit.extend(
1251                    buffer_state
1252                        .excerpts
1253                        .iter()
1254                        .map(|excerpt_id| (excerpt_id, buffer_state.buffer.clone(), buffer_edited)),
1255                );
1256            }
1257
1258            edited |= buffer_edited;
1259            reparsed |= buffer_reparsed;
1260            diagnostics_updated |= buffer_diagnostics_updated;
1261            is_dirty |= buffer.is_dirty();
1262            has_conflict |= buffer.has_conflict();
1263        }
1264        if edited {
1265            snapshot.edit_count += 1;
1266        }
1267        if reparsed {
1268            snapshot.parse_count += 1;
1269        }
1270        if diagnostics_updated {
1271            snapshot.diagnostics_update_count += 1;
1272        }
1273        snapshot.is_dirty = is_dirty;
1274        snapshot.has_conflict = has_conflict;
1275
1276        excerpts_to_edit.sort_unstable_by_key(|(excerpt_id, _, _)| *excerpt_id);
1277
1278        let mut edits = Vec::new();
1279        let mut new_excerpts = SumTree::new();
1280        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
1281
1282        for (id, buffer, buffer_edited) in excerpts_to_edit {
1283            new_excerpts.push_tree(cursor.slice(&Some(id), Bias::Left, &()), &());
1284            let old_excerpt = cursor.item().unwrap();
1285            let buffer_id = buffer.id();
1286            let buffer = buffer.read(cx);
1287
1288            let mut new_excerpt;
1289            if buffer_edited {
1290                edits.extend(
1291                    buffer
1292                        .edits_since_in_range::<usize>(
1293                            old_excerpt.buffer.version(),
1294                            old_excerpt.range.context.clone(),
1295                        )
1296                        .map(|mut edit| {
1297                            let excerpt_old_start = cursor.start().1;
1298                            let excerpt_new_start = new_excerpts.summary().text.bytes;
1299                            edit.old.start += excerpt_old_start;
1300                            edit.old.end += excerpt_old_start;
1301                            edit.new.start += excerpt_new_start;
1302                            edit.new.end += excerpt_new_start;
1303                            edit
1304                        }),
1305                );
1306
1307                new_excerpt = Excerpt::new(
1308                    id.clone(),
1309                    old_excerpt.key,
1310                    buffer_id,
1311                    buffer.snapshot(),
1312                    old_excerpt.range.clone(),
1313                    old_excerpt.has_trailing_newline,
1314                );
1315            } else {
1316                new_excerpt = old_excerpt.clone();
1317                new_excerpt.buffer = buffer.snapshot();
1318            }
1319
1320            new_excerpts.push(new_excerpt, &());
1321            cursor.next(&());
1322        }
1323        new_excerpts.push_tree(cursor.suffix(&()), &());
1324
1325        drop(cursor);
1326        snapshot.excerpts = new_excerpts;
1327
1328        self.subscriptions.publish(edits);
1329    }
1330}
1331
1332#[cfg(any(test, feature = "test-support"))]
1333impl MultiBuffer {
1334    pub fn build_simple(text: &str, cx: &mut gpui::MutableAppContext) -> ModelHandle<Self> {
1335        let buffer = cx.add_model(|cx| Buffer::new(0, text, cx));
1336        cx.add_model(|cx| Self::singleton(buffer, cx))
1337    }
1338
1339    pub fn build_random(
1340        rng: &mut impl rand::Rng,
1341        cx: &mut gpui::MutableAppContext,
1342    ) -> ModelHandle<Self> {
1343        cx.add_model(|cx| {
1344            let mut multibuffer = MultiBuffer::new(0);
1345            let mutation_count = rng.gen_range(1..=5);
1346            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
1347            multibuffer
1348        })
1349    }
1350
1351    pub fn randomly_edit(
1352        &mut self,
1353        rng: &mut impl rand::Rng,
1354        edit_count: usize,
1355        cx: &mut ModelContext<Self>,
1356    ) {
1357        use text::RandomCharIter;
1358
1359        let snapshot = self.read(cx);
1360        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
1361        let mut last_end = None;
1362        for _ in 0..edit_count {
1363            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
1364                break;
1365            }
1366
1367            let new_start = last_end.map_or(0, |last_end| last_end + 1);
1368            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
1369            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
1370            last_end = Some(end);
1371
1372            let mut range = start..end;
1373            if rng.gen_bool(0.2) {
1374                mem::swap(&mut range.start, &mut range.end);
1375            }
1376
1377            let new_text_len = rng.gen_range(0..10);
1378            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1379
1380            edits.push((range, new_text.into()));
1381        }
1382        log::info!("mutating multi-buffer with {:?}", edits);
1383        drop(snapshot);
1384
1385        self.edit(edits, cx);
1386    }
1387
1388    pub fn randomly_edit_excerpts(
1389        &mut self,
1390        rng: &mut impl rand::Rng,
1391        mutation_count: usize,
1392        cx: &mut ModelContext<Self>,
1393    ) {
1394        use rand::prelude::*;
1395        use std::env;
1396        use text::RandomCharIter;
1397
1398        let max_excerpts = env::var("MAX_EXCERPTS")
1399            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
1400            .unwrap_or(5);
1401
1402        let mut buffers = Vec::new();
1403        for _ in 0..mutation_count {
1404            if rng.gen_bool(0.05) {
1405                log::info!("Clearing multi-buffer");
1406                self.clear(cx);
1407                continue;
1408            }
1409
1410            let excerpt_ids = self
1411                .buffers
1412                .borrow()
1413                .values()
1414                .flat_map(|b| &b.excerpts)
1415                .cloned()
1416                .collect::<Vec<_>>();
1417            if excerpt_ids.len() == 0 || (rng.gen() && excerpt_ids.len() < max_excerpts) {
1418                let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
1419                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
1420                    buffers.push(cx.add_model(|cx| Buffer::new(0, text, cx)));
1421                    let buffer = buffers.last().unwrap();
1422                    log::info!(
1423                        "Creating new buffer {} with text: {:?}",
1424                        buffer.id(),
1425                        buffer.read(cx).text()
1426                    );
1427                    buffers.last().unwrap().clone()
1428                } else {
1429                    self.buffers
1430                        .borrow()
1431                        .values()
1432                        .choose(rng)
1433                        .unwrap()
1434                        .buffer
1435                        .clone()
1436                };
1437
1438                let buffer = buffer_handle.read(cx);
1439                let buffer_text = buffer.text();
1440                let ranges = (0..rng.gen_range(0..5))
1441                    .map(|_| {
1442                        let end_ix =
1443                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
1444                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
1445                        ExcerptRange {
1446                            context: start_ix..end_ix,
1447                            primary: None,
1448                        }
1449                    })
1450                    .collect::<Vec<_>>();
1451                log::info!(
1452                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
1453                    buffer_handle.id(),
1454                    ranges,
1455                    ranges
1456                        .iter()
1457                        .map(|range| &buffer_text[range.context.clone()])
1458                        .collect::<Vec<_>>()
1459                );
1460
1461                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
1462                log::info!("Inserted with id: {:?}", excerpt_id);
1463            } else {
1464                let remove_count = rng.gen_range(1..=excerpt_ids.len());
1465                let mut excerpts_to_remove = excerpt_ids
1466                    .choose_multiple(rng, remove_count)
1467                    .cloned()
1468                    .collect::<Vec<_>>();
1469                excerpts_to_remove.sort();
1470                log::info!("Removing excerpts {:?}", excerpts_to_remove);
1471                self.remove_excerpts(&excerpts_to_remove, cx);
1472            }
1473        }
1474    }
1475
1476    pub fn randomly_mutate(
1477        &mut self,
1478        rng: &mut impl rand::Rng,
1479        mutation_count: usize,
1480        cx: &mut ModelContext<Self>,
1481    ) {
1482        use rand::prelude::*;
1483
1484        if rng.gen_bool(0.7) || self.singleton {
1485            let buffer = self
1486                .buffers
1487                .borrow()
1488                .values()
1489                .choose(rng)
1490                .map(|state| state.buffer.clone());
1491
1492            if rng.gen() && buffer.is_some() {
1493                buffer.unwrap().update(cx, |buffer, cx| {
1494                    if rng.gen() {
1495                        buffer.randomly_edit(rng, mutation_count, cx);
1496                    } else {
1497                        buffer.randomly_undo_redo(rng, cx);
1498                    }
1499                });
1500            } else {
1501                self.randomly_edit(rng, mutation_count, cx);
1502            }
1503        } else {
1504            self.randomly_edit_excerpts(rng, mutation_count, cx);
1505        }
1506    }
1507}
1508
1509impl Entity for MultiBuffer {
1510    type Event = language::Event;
1511}
1512
1513impl MultiBufferSnapshot {
1514    pub fn text(&self) -> String {
1515        self.chunks(0..self.len(), false)
1516            .map(|chunk| chunk.text)
1517            .collect()
1518    }
1519
1520    pub fn reversed_chars_at<'a, T: ToOffset>(
1521        &'a self,
1522        position: T,
1523    ) -> impl Iterator<Item = char> + 'a {
1524        let mut offset = position.to_offset(self);
1525        let mut cursor = self.excerpts.cursor::<usize>();
1526        cursor.seek(&offset, Bias::Left, &());
1527        let mut excerpt_chunks = cursor.item().map(|excerpt| {
1528            let end_before_footer = cursor.start() + excerpt.text_summary.bytes;
1529            let start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1530            let end = start + (cmp::min(offset, end_before_footer) - cursor.start());
1531            excerpt.buffer.reversed_chunks_in_range(start..end)
1532        });
1533        iter::from_fn(move || {
1534            if offset == *cursor.start() {
1535                cursor.prev(&());
1536                let excerpt = cursor.item()?;
1537                excerpt_chunks = Some(
1538                    excerpt
1539                        .buffer
1540                        .reversed_chunks_in_range(excerpt.range.context.clone()),
1541                );
1542            }
1543
1544            let excerpt = cursor.item().unwrap();
1545            if offset == cursor.end(&()) && excerpt.has_trailing_newline {
1546                offset -= 1;
1547                Some("\n")
1548            } else {
1549                let chunk = excerpt_chunks.as_mut().unwrap().next().unwrap();
1550                offset -= chunk.len();
1551                Some(chunk)
1552            }
1553        })
1554        .flat_map(|c| c.chars().rev())
1555    }
1556
1557    pub fn chars_at<'a, T: ToOffset>(&'a self, position: T) -> impl Iterator<Item = char> + 'a {
1558        let offset = position.to_offset(self);
1559        self.text_for_range(offset..self.len())
1560            .flat_map(|chunk| chunk.chars())
1561    }
1562
1563    pub fn text_for_range<'a, T: ToOffset>(
1564        &'a self,
1565        range: Range<T>,
1566    ) -> impl Iterator<Item = &'a str> {
1567        self.chunks(range, false).map(|chunk| chunk.text)
1568    }
1569
1570    pub fn is_line_blank(&self, row: u32) -> bool {
1571        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1572            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1573    }
1574
1575    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1576    where
1577        T: ToOffset,
1578    {
1579        let position = position.to_offset(self);
1580        position == self.clip_offset(position, Bias::Left)
1581            && self
1582                .bytes_in_range(position..self.len())
1583                .flatten()
1584                .copied()
1585                .take(needle.len())
1586                .eq(needle.bytes())
1587    }
1588
1589    pub fn surrounding_word<T: ToOffset>(&self, start: T) -> (Range<usize>, Option<CharKind>) {
1590        let mut start = start.to_offset(self);
1591        let mut end = start;
1592        let mut next_chars = self.chars_at(start).peekable();
1593        let mut prev_chars = self.reversed_chars_at(start).peekable();
1594        let word_kind = cmp::max(
1595            prev_chars.peek().copied().map(char_kind),
1596            next_chars.peek().copied().map(char_kind),
1597        );
1598
1599        for ch in prev_chars {
1600            if Some(char_kind(ch)) == word_kind && ch != '\n' {
1601                start -= ch.len_utf8();
1602            } else {
1603                break;
1604            }
1605        }
1606
1607        for ch in next_chars {
1608            if Some(char_kind(ch)) == word_kind && ch != '\n' {
1609                end += ch.len_utf8();
1610            } else {
1611                break;
1612            }
1613        }
1614
1615        (start..end, word_kind)
1616    }
1617
1618    pub fn as_singleton(&self) -> Option<(&ExcerptId, usize, &BufferSnapshot)> {
1619        if self.singleton {
1620            self.excerpts
1621                .iter()
1622                .next()
1623                .map(|e| (&e.id, e.buffer_id, &e.buffer))
1624        } else {
1625            None
1626        }
1627    }
1628
1629    pub fn len(&self) -> usize {
1630        self.excerpts.summary().text.bytes
1631    }
1632
1633    pub fn max_buffer_row(&self) -> u32 {
1634        self.excerpts.summary().max_buffer_row
1635    }
1636
1637    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
1638        if let Some((_, _, buffer)) = self.as_singleton() {
1639            return buffer.clip_offset(offset, bias);
1640        }
1641
1642        let mut cursor = self.excerpts.cursor::<usize>();
1643        cursor.seek(&offset, Bias::Right, &());
1644        let overshoot = if let Some(excerpt) = cursor.item() {
1645            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1646            let buffer_offset = excerpt
1647                .buffer
1648                .clip_offset(excerpt_start + (offset - cursor.start()), bias);
1649            buffer_offset.saturating_sub(excerpt_start)
1650        } else {
1651            0
1652        };
1653        cursor.start() + overshoot
1654    }
1655
1656    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1657        if let Some((_, _, buffer)) = self.as_singleton() {
1658            return buffer.clip_point(point, bias);
1659        }
1660
1661        let mut cursor = self.excerpts.cursor::<Point>();
1662        cursor.seek(&point, Bias::Right, &());
1663        let overshoot = if let Some(excerpt) = cursor.item() {
1664            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
1665            let buffer_point = excerpt
1666                .buffer
1667                .clip_point(excerpt_start + (point - cursor.start()), bias);
1668            buffer_point.saturating_sub(excerpt_start)
1669        } else {
1670            Point::zero()
1671        };
1672        *cursor.start() + overshoot
1673    }
1674
1675    pub fn clip_point_utf16(&self, point: PointUtf16, bias: Bias) -> PointUtf16 {
1676        if let Some((_, _, buffer)) = self.as_singleton() {
1677            return buffer.clip_point_utf16(point, bias);
1678        }
1679
1680        let mut cursor = self.excerpts.cursor::<PointUtf16>();
1681        cursor.seek(&point, Bias::Right, &());
1682        let overshoot = if let Some(excerpt) = cursor.item() {
1683            let excerpt_start = excerpt
1684                .buffer
1685                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
1686            let buffer_point = excerpt
1687                .buffer
1688                .clip_point_utf16(excerpt_start + (point - cursor.start()), bias);
1689            buffer_point.saturating_sub(excerpt_start)
1690        } else {
1691            PointUtf16::zero()
1692        };
1693        *cursor.start() + overshoot
1694    }
1695
1696    pub fn bytes_in_range<'a, T: ToOffset>(&'a self, range: Range<T>) -> MultiBufferBytes<'a> {
1697        let range = range.start.to_offset(self)..range.end.to_offset(self);
1698        let mut excerpts = self.excerpts.cursor::<usize>();
1699        excerpts.seek(&range.start, Bias::Right, &());
1700
1701        let mut chunk = &[][..];
1702        let excerpt_bytes = if let Some(excerpt) = excerpts.item() {
1703            let mut excerpt_bytes = excerpt
1704                .bytes_in_range(range.start - excerpts.start()..range.end - excerpts.start());
1705            chunk = excerpt_bytes.next().unwrap_or(&[][..]);
1706            Some(excerpt_bytes)
1707        } else {
1708            None
1709        };
1710
1711        MultiBufferBytes {
1712            range,
1713            excerpts,
1714            excerpt_bytes,
1715            chunk,
1716        }
1717    }
1718
1719    pub fn buffer_rows<'a>(&'a self, start_row: u32) -> MultiBufferRows<'a> {
1720        let mut result = MultiBufferRows {
1721            buffer_row_range: 0..0,
1722            excerpts: self.excerpts.cursor(),
1723        };
1724        result.seek(start_row);
1725        result
1726    }
1727
1728    pub fn chunks<'a, T: ToOffset>(
1729        &'a self,
1730        range: Range<T>,
1731        language_aware: bool,
1732    ) -> MultiBufferChunks<'a> {
1733        let range = range.start.to_offset(self)..range.end.to_offset(self);
1734        let mut chunks = MultiBufferChunks {
1735            range: range.clone(),
1736            excerpts: self.excerpts.cursor(),
1737            excerpt_chunks: None,
1738            language_aware,
1739        };
1740        chunks.seek(range.start);
1741        chunks
1742    }
1743
1744    pub fn offset_to_point(&self, offset: usize) -> Point {
1745        if let Some((_, _, buffer)) = self.as_singleton() {
1746            return buffer.offset_to_point(offset);
1747        }
1748
1749        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
1750        cursor.seek(&offset, Bias::Right, &());
1751        if let Some(excerpt) = cursor.item() {
1752            let (start_offset, start_point) = cursor.start();
1753            let overshoot = offset - start_offset;
1754            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
1755            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
1756            let buffer_point = excerpt
1757                .buffer
1758                .offset_to_point(excerpt_start_offset + overshoot);
1759            *start_point + (buffer_point - excerpt_start_point)
1760        } else {
1761            self.excerpts.summary().text.lines
1762        }
1763    }
1764
1765    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
1766        if let Some((_, _, buffer)) = self.as_singleton() {
1767            return buffer.offset_to_point_utf16(offset);
1768        }
1769
1770        let mut cursor = self.excerpts.cursor::<(usize, PointUtf16)>();
1771        cursor.seek(&offset, Bias::Right, &());
1772        if let Some(excerpt) = cursor.item() {
1773            let (start_offset, start_point) = cursor.start();
1774            let overshoot = offset - start_offset;
1775            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
1776            let excerpt_start_point = excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
1777            let buffer_point = excerpt
1778                .buffer
1779                .offset_to_point_utf16(excerpt_start_offset + overshoot);
1780            *start_point + (buffer_point - excerpt_start_point)
1781        } else {
1782            self.excerpts.summary().text.lines_utf16
1783        }
1784    }
1785
1786    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
1787        if let Some((_, _, buffer)) = self.as_singleton() {
1788            return buffer.point_to_point_utf16(point);
1789        }
1790
1791        let mut cursor = self.excerpts.cursor::<(Point, PointUtf16)>();
1792        cursor.seek(&point, Bias::Right, &());
1793        if let Some(excerpt) = cursor.item() {
1794            let (start_offset, start_point) = cursor.start();
1795            let overshoot = point - start_offset;
1796            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
1797            let excerpt_start_point_utf16 =
1798                excerpt.range.context.start.to_point_utf16(&excerpt.buffer);
1799            let buffer_point = excerpt
1800                .buffer
1801                .point_to_point_utf16(excerpt_start_point + overshoot);
1802            *start_point + (buffer_point - excerpt_start_point_utf16)
1803        } else {
1804            self.excerpts.summary().text.lines_utf16
1805        }
1806    }
1807
1808    pub fn point_to_offset(&self, point: Point) -> usize {
1809        if let Some((_, _, buffer)) = self.as_singleton() {
1810            return buffer.point_to_offset(point);
1811        }
1812
1813        let mut cursor = self.excerpts.cursor::<(Point, usize)>();
1814        cursor.seek(&point, Bias::Right, &());
1815        if let Some(excerpt) = cursor.item() {
1816            let (start_point, start_offset) = cursor.start();
1817            let overshoot = point - start_point;
1818            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
1819            let excerpt_start_point = excerpt.range.context.start.to_point(&excerpt.buffer);
1820            let buffer_offset = excerpt
1821                .buffer
1822                .point_to_offset(excerpt_start_point + overshoot);
1823            *start_offset + buffer_offset - excerpt_start_offset
1824        } else {
1825            self.excerpts.summary().text.bytes
1826        }
1827    }
1828
1829    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
1830        if let Some((_, _, buffer)) = self.as_singleton() {
1831            return buffer.point_utf16_to_offset(point);
1832        }
1833
1834        let mut cursor = self.excerpts.cursor::<(PointUtf16, usize)>();
1835        cursor.seek(&point, Bias::Right, &());
1836        if let Some(excerpt) = cursor.item() {
1837            let (start_point, start_offset) = cursor.start();
1838            let overshoot = point - start_point;
1839            let excerpt_start_offset = excerpt.range.context.start.to_offset(&excerpt.buffer);
1840            let excerpt_start_point = excerpt
1841                .buffer
1842                .offset_to_point_utf16(excerpt.range.context.start.to_offset(&excerpt.buffer));
1843            let buffer_offset = excerpt
1844                .buffer
1845                .point_utf16_to_offset(excerpt_start_point + overshoot);
1846            *start_offset + (buffer_offset - excerpt_start_offset)
1847        } else {
1848            self.excerpts.summary().text.bytes
1849        }
1850    }
1851
1852    pub fn indent_size_for_line(&self, row: u32) -> IndentSize {
1853        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
1854            let mut size = buffer.indent_size_for_line(range.start.row);
1855            size.len = size
1856                .len
1857                .min(range.end.column)
1858                .saturating_sub(range.start.column);
1859            size
1860        } else {
1861            IndentSize::spaces(0)
1862        }
1863    }
1864
1865    pub fn line_len(&self, row: u32) -> u32 {
1866        if let Some((_, range)) = self.buffer_line_for_row(row) {
1867            range.end.column - range.start.column
1868        } else {
1869            0
1870        }
1871    }
1872
1873    pub fn buffer_line_for_row(&self, row: u32) -> Option<(&BufferSnapshot, Range<Point>)> {
1874        let mut cursor = self.excerpts.cursor::<Point>();
1875        cursor.seek(&Point::new(row, 0), Bias::Right, &());
1876        if let Some(excerpt) = cursor.item() {
1877            let overshoot = row - cursor.start().row;
1878            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer);
1879            let excerpt_end = excerpt.range.context.end.to_point(&excerpt.buffer);
1880            let buffer_row = excerpt_start.row + overshoot;
1881            let line_start = Point::new(buffer_row, 0);
1882            let line_end = Point::new(buffer_row, excerpt.buffer.line_len(buffer_row));
1883            return Some((
1884                &excerpt.buffer,
1885                line_start.max(excerpt_start)..line_end.min(excerpt_end),
1886            ));
1887        }
1888        None
1889    }
1890
1891    pub fn max_point(&self) -> Point {
1892        self.text_summary().lines
1893    }
1894
1895    pub fn text_summary(&self) -> TextSummary {
1896        self.excerpts.summary().text.clone()
1897    }
1898
1899    pub fn text_summary_for_range<'a, D, O>(&'a self, range: Range<O>) -> D
1900    where
1901        D: TextDimension,
1902        O: ToOffset,
1903    {
1904        let mut summary = D::default();
1905        let mut range = range.start.to_offset(self)..range.end.to_offset(self);
1906        let mut cursor = self.excerpts.cursor::<usize>();
1907        cursor.seek(&range.start, Bias::Right, &());
1908        if let Some(excerpt) = cursor.item() {
1909            let mut end_before_newline = cursor.end(&());
1910            if excerpt.has_trailing_newline {
1911                end_before_newline -= 1;
1912            }
1913
1914            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1915            let start_in_excerpt = excerpt_start + (range.start - cursor.start());
1916            let end_in_excerpt =
1917                excerpt_start + (cmp::min(end_before_newline, range.end) - cursor.start());
1918            summary.add_assign(
1919                &excerpt
1920                    .buffer
1921                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
1922            );
1923
1924            if range.end > end_before_newline {
1925                summary.add_assign(&D::from_text_summary(&TextSummary {
1926                    bytes: 1,
1927                    lines: Point::new(1 as u32, 0),
1928                    lines_utf16: PointUtf16::new(1 as u32, 0),
1929                    first_line_chars: 0,
1930                    last_line_chars: 0,
1931                    longest_row: 0,
1932                    longest_row_chars: 0,
1933                }));
1934            }
1935
1936            cursor.next(&());
1937        }
1938
1939        if range.end > *cursor.start() {
1940            summary.add_assign(&D::from_text_summary(&cursor.summary::<_, TextSummary>(
1941                &range.end,
1942                Bias::Right,
1943                &(),
1944            )));
1945            if let Some(excerpt) = cursor.item() {
1946                range.end = cmp::max(*cursor.start(), range.end);
1947
1948                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
1949                let end_in_excerpt = excerpt_start + (range.end - cursor.start());
1950                summary.add_assign(
1951                    &excerpt
1952                        .buffer
1953                        .text_summary_for_range(excerpt_start..end_in_excerpt),
1954                );
1955            }
1956        }
1957
1958        summary
1959    }
1960
1961    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
1962    where
1963        D: TextDimension + Ord + Sub<D, Output = D>,
1964    {
1965        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
1966        cursor.seek(&Some(&anchor.excerpt_id), Bias::Left, &());
1967        if cursor.item().is_none() {
1968            cursor.next(&());
1969        }
1970
1971        let mut position = D::from_text_summary(&cursor.start().text);
1972        if let Some(excerpt) = cursor.item() {
1973            if excerpt.id == anchor.excerpt_id {
1974                let excerpt_buffer_start =
1975                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
1976                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
1977                let buffer_position = cmp::min(
1978                    excerpt_buffer_end,
1979                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
1980                );
1981                if buffer_position > excerpt_buffer_start {
1982                    position.add_assign(&(buffer_position - excerpt_buffer_start));
1983                }
1984            }
1985        }
1986        position
1987    }
1988
1989    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
1990    where
1991        D: TextDimension + Ord + Sub<D, Output = D>,
1992        I: 'a + IntoIterator<Item = &'a Anchor>,
1993    {
1994        if let Some((_, _, buffer)) = self.as_singleton() {
1995            return buffer
1996                .summaries_for_anchors(anchors.into_iter().map(|a| &a.text_anchor))
1997                .collect();
1998        }
1999
2000        let mut anchors = anchors.into_iter().peekable();
2001        let mut cursor = self.excerpts.cursor::<ExcerptSummary>();
2002        let mut summaries = Vec::new();
2003        while let Some(anchor) = anchors.peek() {
2004            let excerpt_id = &anchor.excerpt_id;
2005            let excerpt_anchors = iter::from_fn(|| {
2006                let anchor = anchors.peek()?;
2007                if anchor.excerpt_id == *excerpt_id {
2008                    Some(&anchors.next().unwrap().text_anchor)
2009                } else {
2010                    None
2011                }
2012            });
2013
2014            cursor.seek_forward(&Some(excerpt_id), Bias::Left, &());
2015            if cursor.item().is_none() {
2016                cursor.next(&());
2017            }
2018
2019            let position = D::from_text_summary(&cursor.start().text);
2020            if let Some(excerpt) = cursor.item() {
2021                if excerpt.id == *excerpt_id {
2022                    let excerpt_buffer_start =
2023                        excerpt.range.context.start.summary::<D>(&excerpt.buffer);
2024                    let excerpt_buffer_end =
2025                        excerpt.range.context.end.summary::<D>(&excerpt.buffer);
2026                    summaries.extend(
2027                        excerpt
2028                            .buffer
2029                            .summaries_for_anchors::<D, _>(excerpt_anchors)
2030                            .map(move |summary| {
2031                                let summary = cmp::min(excerpt_buffer_end.clone(), summary);
2032                                let mut position = position.clone();
2033                                let excerpt_buffer_start = excerpt_buffer_start.clone();
2034                                if summary > excerpt_buffer_start {
2035                                    position.add_assign(&(summary - excerpt_buffer_start));
2036                                }
2037                                position
2038                            }),
2039                    );
2040                    continue;
2041                }
2042            }
2043
2044            summaries.extend(excerpt_anchors.map(|_| position.clone()));
2045        }
2046
2047        summaries
2048    }
2049
2050    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
2051    where
2052        I: 'a + IntoIterator<Item = &'a Anchor>,
2053    {
2054        let mut anchors = anchors.into_iter().enumerate().peekable();
2055        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2056        let mut result = Vec::new();
2057        while let Some((_, anchor)) = anchors.peek() {
2058            let old_excerpt_id = &anchor.excerpt_id;
2059
2060            // Find the location where this anchor's excerpt should be.
2061            cursor.seek_forward(&Some(old_excerpt_id), Bias::Left, &());
2062            if cursor.item().is_none() {
2063                cursor.next(&());
2064            }
2065
2066            let next_excerpt = cursor.item();
2067            let prev_excerpt = cursor.prev_item();
2068
2069            // Process all of the anchors for this excerpt.
2070            while let Some((_, anchor)) = anchors.peek() {
2071                if anchor.excerpt_id != *old_excerpt_id {
2072                    break;
2073                }
2074                let mut kept_position = false;
2075                let (anchor_ix, anchor) = anchors.next().unwrap();
2076                let mut anchor = anchor.clone();
2077
2078                // Leave min and max anchors unchanged.
2079                if *old_excerpt_id == ExcerptId::max() || *old_excerpt_id == ExcerptId::min() {
2080                    kept_position = true;
2081                }
2082                // If the old excerpt still exists at this location, then leave
2083                // the anchor unchanged.
2084                else if next_excerpt.map_or(false, |excerpt| {
2085                    excerpt.id == *old_excerpt_id && excerpt.contains(&anchor)
2086                }) {
2087                    kept_position = true;
2088                }
2089                // If the old excerpt no longer exists at this location, then attempt to
2090                // find an equivalent position for this anchor in an adjacent excerpt.
2091                else {
2092                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
2093                        if excerpt.contains(&anchor) {
2094                            anchor.excerpt_id = excerpt.id.clone();
2095                            kept_position = true;
2096                            break;
2097                        }
2098                    }
2099                }
2100                // If there's no adjacent excerpt that contains the anchor's position,
2101                // then report that the anchor has lost its position.
2102                if !kept_position {
2103                    anchor = if let Some(excerpt) = next_excerpt {
2104                        let mut text_anchor = excerpt
2105                            .range
2106                            .context
2107                            .start
2108                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2109                        if text_anchor
2110                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
2111                            .is_gt()
2112                        {
2113                            text_anchor = excerpt.range.context.end.clone();
2114                        }
2115                        Anchor {
2116                            buffer_id: Some(excerpt.buffer_id),
2117                            excerpt_id: excerpt.id.clone(),
2118                            text_anchor,
2119                        }
2120                    } else if let Some(excerpt) = prev_excerpt {
2121                        let mut text_anchor = excerpt
2122                            .range
2123                            .context
2124                            .end
2125                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
2126                        if text_anchor
2127                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
2128                            .is_lt()
2129                        {
2130                            text_anchor = excerpt.range.context.start.clone();
2131                        }
2132                        Anchor {
2133                            buffer_id: Some(excerpt.buffer_id),
2134                            excerpt_id: excerpt.id.clone(),
2135                            text_anchor,
2136                        }
2137                    } else if anchor.text_anchor.bias == Bias::Left {
2138                        Anchor::min()
2139                    } else {
2140                        Anchor::max()
2141                    };
2142                }
2143
2144                result.push((anchor_ix, anchor, kept_position));
2145            }
2146        }
2147        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
2148        result
2149    }
2150
2151    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
2152        self.anchor_at(position, Bias::Left)
2153    }
2154
2155    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
2156        self.anchor_at(position, Bias::Right)
2157    }
2158
2159    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
2160        let offset = position.to_offset(self);
2161        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
2162            return Anchor {
2163                buffer_id: Some(buffer_id),
2164                excerpt_id: excerpt_id.clone(),
2165                text_anchor: buffer.anchor_at(offset, bias),
2166            };
2167        }
2168
2169        let mut cursor = self.excerpts.cursor::<(usize, Option<&ExcerptId>)>();
2170        cursor.seek(&offset, Bias::Right, &());
2171        if cursor.item().is_none() && offset == cursor.start().0 && bias == Bias::Left {
2172            cursor.prev(&());
2173        }
2174        if let Some(excerpt) = cursor.item() {
2175            let mut overshoot = offset.saturating_sub(cursor.start().0);
2176            if excerpt.has_trailing_newline && offset == cursor.end(&()).0 {
2177                overshoot -= 1;
2178                bias = Bias::Right;
2179            }
2180
2181            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
2182            let text_anchor =
2183                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
2184            Anchor {
2185                buffer_id: Some(excerpt.buffer_id),
2186                excerpt_id: excerpt.id.clone(),
2187                text_anchor,
2188            }
2189        } else if offset == 0 && bias == Bias::Left {
2190            Anchor::min()
2191        } else {
2192            Anchor::max()
2193        }
2194    }
2195
2196    pub fn anchor_in_excerpt(&self, excerpt_id: ExcerptId, text_anchor: text::Anchor) -> Anchor {
2197        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2198        cursor.seek(&Some(&excerpt_id), Bias::Left, &());
2199        if let Some(excerpt) = cursor.item() {
2200            if excerpt.id == excerpt_id {
2201                let text_anchor = excerpt.clip_anchor(text_anchor);
2202                drop(cursor);
2203                return Anchor {
2204                    buffer_id: Some(excerpt.buffer_id),
2205                    excerpt_id,
2206                    text_anchor,
2207                };
2208            }
2209        }
2210        panic!("excerpt not found");
2211    }
2212
2213    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
2214        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
2215            true
2216        } else if let Some(excerpt) = self.excerpt(&anchor.excerpt_id) {
2217            excerpt.buffer.can_resolve(&anchor.text_anchor)
2218        } else {
2219            false
2220        }
2221    }
2222
2223    pub fn excerpt_boundaries_in_range<'a, R, T>(
2224        &'a self,
2225        range: R,
2226    ) -> impl Iterator<Item = ExcerptBoundary> + 'a
2227    where
2228        R: RangeBounds<T>,
2229        T: ToOffset,
2230    {
2231        let start_offset;
2232        let start = match range.start_bound() {
2233            Bound::Included(start) => {
2234                start_offset = start.to_offset(self);
2235                Bound::Included(start_offset)
2236            }
2237            Bound::Excluded(start) => {
2238                start_offset = start.to_offset(self);
2239                Bound::Excluded(start_offset)
2240            }
2241            Bound::Unbounded => {
2242                start_offset = 0;
2243                Bound::Unbounded
2244            }
2245        };
2246        let end = match range.end_bound() {
2247            Bound::Included(end) => Bound::Included(end.to_offset(self)),
2248            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
2249            Bound::Unbounded => Bound::Unbounded,
2250        };
2251        let bounds = (start, end);
2252
2253        let mut cursor = self.excerpts.cursor::<(usize, Point)>();
2254        cursor.seek(&start_offset, Bias::Right, &());
2255        if cursor.item().is_none() {
2256            cursor.prev(&());
2257        }
2258        if !bounds.contains(&cursor.start().0) {
2259            cursor.next(&());
2260        }
2261
2262        let mut prev_buffer_id = cursor.prev_item().map(|excerpt| excerpt.buffer_id);
2263        std::iter::from_fn(move || {
2264            if self.singleton {
2265                None
2266            } else if bounds.contains(&cursor.start().0) {
2267                let excerpt = cursor.item()?;
2268                let starts_new_buffer = Some(excerpt.buffer_id) != prev_buffer_id;
2269                let boundary = ExcerptBoundary {
2270                    id: excerpt.id.clone(),
2271                    key: excerpt.key,
2272                    row: cursor.start().1.row,
2273                    buffer: excerpt.buffer.clone(),
2274                    range: excerpt.range.clone(),
2275                    starts_new_buffer,
2276                };
2277
2278                prev_buffer_id = Some(excerpt.buffer_id);
2279                cursor.next(&());
2280                Some(boundary)
2281            } else {
2282                None
2283            }
2284        })
2285    }
2286
2287    pub fn edit_count(&self) -> usize {
2288        self.edit_count
2289    }
2290
2291    pub fn parse_count(&self) -> usize {
2292        self.parse_count
2293    }
2294
2295    pub fn enclosing_bracket_ranges<T: ToOffset>(
2296        &self,
2297        range: Range<T>,
2298    ) -> Option<(Range<usize>, Range<usize>)> {
2299        let range = range.start.to_offset(self)..range.end.to_offset(self);
2300
2301        let mut cursor = self.excerpts.cursor::<usize>();
2302        cursor.seek(&range.start, Bias::Right, &());
2303        let start_excerpt = cursor.item();
2304
2305        cursor.seek(&range.end, Bias::Right, &());
2306        let end_excerpt = cursor.item();
2307
2308        start_excerpt
2309            .zip(end_excerpt)
2310            .and_then(|(start_excerpt, end_excerpt)| {
2311                if start_excerpt.id != end_excerpt.id {
2312                    return None;
2313                }
2314
2315                let excerpt_buffer_start = start_excerpt
2316                    .range
2317                    .context
2318                    .start
2319                    .to_offset(&start_excerpt.buffer);
2320                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
2321
2322                let start_in_buffer =
2323                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
2324                let end_in_buffer =
2325                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
2326                let (mut start_bracket_range, mut end_bracket_range) = start_excerpt
2327                    .buffer
2328                    .enclosing_bracket_ranges(start_in_buffer..end_in_buffer)?;
2329
2330                if start_bracket_range.start >= excerpt_buffer_start
2331                    && end_bracket_range.end < excerpt_buffer_end
2332                {
2333                    start_bracket_range.start =
2334                        cursor.start() + (start_bracket_range.start - excerpt_buffer_start);
2335                    start_bracket_range.end =
2336                        cursor.start() + (start_bracket_range.end - excerpt_buffer_start);
2337                    end_bracket_range.start =
2338                        cursor.start() + (end_bracket_range.start - excerpt_buffer_start);
2339                    end_bracket_range.end =
2340                        cursor.start() + (end_bracket_range.end - excerpt_buffer_start);
2341                    Some((start_bracket_range, end_bracket_range))
2342                } else {
2343                    None
2344                }
2345            })
2346    }
2347
2348    pub fn diagnostics_update_count(&self) -> usize {
2349        self.diagnostics_update_count
2350    }
2351
2352    pub fn trailing_excerpt_update_count(&self) -> usize {
2353        self.trailing_excerpt_update_count
2354    }
2355
2356    pub fn language(&self) -> Option<&Arc<Language>> {
2357        self.excerpts
2358            .iter()
2359            .next()
2360            .and_then(|excerpt| excerpt.buffer.language())
2361    }
2362
2363    pub fn is_dirty(&self) -> bool {
2364        self.is_dirty
2365    }
2366
2367    pub fn has_conflict(&self) -> bool {
2368        self.has_conflict
2369    }
2370
2371    pub fn diagnostic_group<'a, O>(
2372        &'a self,
2373        group_id: usize,
2374    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
2375    where
2376        O: text::FromAnchor + 'a,
2377    {
2378        self.as_singleton()
2379            .into_iter()
2380            .flat_map(move |(_, _, buffer)| buffer.diagnostic_group(group_id))
2381    }
2382
2383    pub fn diagnostics_in_range<'a, T, O>(
2384        &'a self,
2385        range: Range<T>,
2386        reversed: bool,
2387    ) -> impl Iterator<Item = DiagnosticEntry<O>> + 'a
2388    where
2389        T: 'a + ToOffset,
2390        O: 'a + text::FromAnchor,
2391    {
2392        self.as_singleton()
2393            .into_iter()
2394            .flat_map(move |(_, _, buffer)| {
2395                buffer.diagnostics_in_range(
2396                    range.start.to_offset(self)..range.end.to_offset(self),
2397                    reversed,
2398                )
2399            })
2400    }
2401
2402    pub fn range_for_syntax_ancestor<T: ToOffset>(&self, range: Range<T>) -> Option<Range<usize>> {
2403        let range = range.start.to_offset(self)..range.end.to_offset(self);
2404
2405        let mut cursor = self.excerpts.cursor::<usize>();
2406        cursor.seek(&range.start, Bias::Right, &());
2407        let start_excerpt = cursor.item();
2408
2409        cursor.seek(&range.end, Bias::Right, &());
2410        let end_excerpt = cursor.item();
2411
2412        start_excerpt
2413            .zip(end_excerpt)
2414            .and_then(|(start_excerpt, end_excerpt)| {
2415                if start_excerpt.id != end_excerpt.id {
2416                    return None;
2417                }
2418
2419                let excerpt_buffer_start = start_excerpt
2420                    .range
2421                    .context
2422                    .start
2423                    .to_offset(&start_excerpt.buffer);
2424                let excerpt_buffer_end = excerpt_buffer_start + start_excerpt.text_summary.bytes;
2425
2426                let start_in_buffer =
2427                    excerpt_buffer_start + range.start.saturating_sub(*cursor.start());
2428                let end_in_buffer =
2429                    excerpt_buffer_start + range.end.saturating_sub(*cursor.start());
2430                let mut ancestor_buffer_range = start_excerpt
2431                    .buffer
2432                    .range_for_syntax_ancestor(start_in_buffer..end_in_buffer)?;
2433                ancestor_buffer_range.start =
2434                    cmp::max(ancestor_buffer_range.start, excerpt_buffer_start);
2435                ancestor_buffer_range.end = cmp::min(ancestor_buffer_range.end, excerpt_buffer_end);
2436
2437                let start = cursor.start() + (ancestor_buffer_range.start - excerpt_buffer_start);
2438                let end = cursor.start() + (ancestor_buffer_range.end - excerpt_buffer_start);
2439                Some(start..end)
2440            })
2441    }
2442
2443    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
2444        let (excerpt_id, _, buffer) = self.as_singleton()?;
2445        let outline = buffer.outline(theme)?;
2446        Some(Outline::new(
2447            outline
2448                .items
2449                .into_iter()
2450                .map(|item| OutlineItem {
2451                    depth: item.depth,
2452                    range: self.anchor_in_excerpt(excerpt_id.clone(), item.range.start)
2453                        ..self.anchor_in_excerpt(excerpt_id.clone(), item.range.end),
2454                    text: item.text,
2455                    highlight_ranges: item.highlight_ranges,
2456                    name_ranges: item.name_ranges,
2457                })
2458                .collect(),
2459        ))
2460    }
2461
2462    pub fn symbols_containing<T: ToOffset>(
2463        &self,
2464        offset: T,
2465        theme: Option<&SyntaxTheme>,
2466    ) -> Option<(usize, Vec<OutlineItem<Anchor>>)> {
2467        let anchor = self.anchor_before(offset);
2468        let excerpt_id = anchor.excerpt_id();
2469        let excerpt = self.excerpt(excerpt_id)?;
2470        Some((
2471            excerpt.buffer_id,
2472            excerpt
2473                .buffer
2474                .symbols_containing(anchor.text_anchor, theme)
2475                .into_iter()
2476                .flatten()
2477                .map(|item| OutlineItem {
2478                    depth: item.depth,
2479                    range: self.anchor_in_excerpt(excerpt_id.clone(), item.range.start)
2480                        ..self.anchor_in_excerpt(excerpt_id.clone(), item.range.end),
2481                    text: item.text,
2482                    highlight_ranges: item.highlight_ranges,
2483                    name_ranges: item.name_ranges,
2484                })
2485                .collect(),
2486        ))
2487    }
2488
2489    fn excerpt<'a>(&'a self, excerpt_id: &'a ExcerptId) -> Option<&'a Excerpt> {
2490        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2491        cursor.seek(&Some(excerpt_id), Bias::Left, &());
2492        if let Some(excerpt) = cursor.item() {
2493            if excerpt.id == *excerpt_id {
2494                return Some(excerpt);
2495            }
2496        }
2497        None
2498    }
2499
2500    pub fn remote_selections_in_range<'a>(
2501        &'a self,
2502        range: &'a Range<Anchor>,
2503    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, Selection<Anchor>)> {
2504        let mut cursor = self.excerpts.cursor::<Option<&ExcerptId>>();
2505        cursor.seek(&Some(&range.start.excerpt_id), Bias::Left, &());
2506        cursor
2507            .take_while(move |excerpt| excerpt.id <= range.end.excerpt_id)
2508            .flat_map(move |excerpt| {
2509                let mut query_range =
2510                    excerpt.range.context.start.clone()..excerpt.range.context.end.clone();
2511                if excerpt.id == range.start.excerpt_id {
2512                    query_range.start = range.start.text_anchor.clone();
2513                }
2514                if excerpt.id == range.end.excerpt_id {
2515                    query_range.end = range.end.text_anchor.clone();
2516                }
2517
2518                excerpt
2519                    .buffer
2520                    .remote_selections_in_range(query_range)
2521                    .flat_map(move |(replica_id, line_mode, selections)| {
2522                        selections.map(move |selection| {
2523                            let mut start = Anchor {
2524                                buffer_id: Some(excerpt.buffer_id),
2525                                excerpt_id: excerpt.id.clone(),
2526                                text_anchor: selection.start.clone(),
2527                            };
2528                            let mut end = Anchor {
2529                                buffer_id: Some(excerpt.buffer_id),
2530                                excerpt_id: excerpt.id.clone(),
2531                                text_anchor: selection.end.clone(),
2532                            };
2533                            if range.start.cmp(&start, self).is_gt() {
2534                                start = range.start.clone();
2535                            }
2536                            if range.end.cmp(&end, self).is_lt() {
2537                                end = range.end.clone();
2538                            }
2539
2540                            (
2541                                replica_id,
2542                                line_mode,
2543                                Selection {
2544                                    id: selection.id,
2545                                    start,
2546                                    end,
2547                                    reversed: selection.reversed,
2548                                    goal: selection.goal,
2549                                },
2550                            )
2551                        })
2552                    })
2553            })
2554    }
2555}
2556
2557#[cfg(any(test, feature = "test-support"))]
2558impl MultiBufferSnapshot {
2559    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
2560        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
2561        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
2562        start..end
2563    }
2564}
2565
2566impl History {
2567    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
2568        self.transaction_depth += 1;
2569        if self.transaction_depth == 1 {
2570            let id = self.next_transaction_id.tick();
2571            self.undo_stack.push(Transaction {
2572                id,
2573                buffer_transactions: Default::default(),
2574                first_edit_at: now,
2575                last_edit_at: now,
2576                suppress_grouping: false,
2577            });
2578            Some(id)
2579        } else {
2580            None
2581        }
2582    }
2583
2584    fn end_transaction(
2585        &mut self,
2586        now: Instant,
2587        buffer_transactions: HashMap<usize, TransactionId>,
2588    ) -> bool {
2589        assert_ne!(self.transaction_depth, 0);
2590        self.transaction_depth -= 1;
2591        if self.transaction_depth == 0 {
2592            if buffer_transactions.is_empty() {
2593                self.undo_stack.pop();
2594                false
2595            } else {
2596                self.redo_stack.clear();
2597                let transaction = self.undo_stack.last_mut().unwrap();
2598                transaction.last_edit_at = now;
2599                for (buffer_id, transaction_id) in buffer_transactions {
2600                    transaction
2601                        .buffer_transactions
2602                        .entry(buffer_id)
2603                        .or_insert(transaction_id);
2604                }
2605                true
2606            }
2607        } else {
2608            false
2609        }
2610    }
2611
2612    fn push_transaction<'a, T>(&mut self, buffer_transactions: T, now: Instant)
2613    where
2614        T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
2615    {
2616        assert_eq!(self.transaction_depth, 0);
2617        let transaction = Transaction {
2618            id: self.next_transaction_id.tick(),
2619            buffer_transactions: buffer_transactions
2620                .into_iter()
2621                .map(|(buffer, transaction)| (buffer.id(), transaction.id))
2622                .collect(),
2623            first_edit_at: now,
2624            last_edit_at: now,
2625            suppress_grouping: false,
2626        };
2627        if !transaction.buffer_transactions.is_empty() {
2628            self.undo_stack.push(transaction);
2629            self.redo_stack.clear();
2630        }
2631    }
2632
2633    fn finalize_last_transaction(&mut self) {
2634        if let Some(transaction) = self.undo_stack.last_mut() {
2635            transaction.suppress_grouping = true;
2636        }
2637    }
2638
2639    fn pop_undo(&mut self) -> Option<&mut Transaction> {
2640        assert_eq!(self.transaction_depth, 0);
2641        if let Some(transaction) = self.undo_stack.pop() {
2642            self.redo_stack.push(transaction);
2643            self.redo_stack.last_mut()
2644        } else {
2645            None
2646        }
2647    }
2648
2649    fn pop_redo(&mut self) -> Option<&mut Transaction> {
2650        assert_eq!(self.transaction_depth, 0);
2651        if let Some(transaction) = self.redo_stack.pop() {
2652            self.undo_stack.push(transaction);
2653            self.undo_stack.last_mut()
2654        } else {
2655            None
2656        }
2657    }
2658
2659    fn group(&mut self) -> Option<TransactionId> {
2660        let mut new_len = self.undo_stack.len();
2661        let mut transactions = self.undo_stack.iter_mut();
2662
2663        if let Some(mut transaction) = transactions.next_back() {
2664            while let Some(prev_transaction) = transactions.next_back() {
2665                if !prev_transaction.suppress_grouping
2666                    && transaction.first_edit_at - prev_transaction.last_edit_at
2667                        <= self.group_interval
2668                {
2669                    transaction = prev_transaction;
2670                    new_len -= 1;
2671                } else {
2672                    break;
2673                }
2674            }
2675        }
2676
2677        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
2678        if let Some(last_transaction) = transactions_to_keep.last_mut() {
2679            if let Some(transaction) = transactions_to_merge.last() {
2680                last_transaction.last_edit_at = transaction.last_edit_at;
2681            }
2682            for to_merge in transactions_to_merge {
2683                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
2684                    last_transaction
2685                        .buffer_transactions
2686                        .entry(*buffer_id)
2687                        .or_insert(*transaction_id);
2688                }
2689            }
2690        }
2691
2692        self.undo_stack.truncate(new_len);
2693        self.undo_stack.last().map(|t| t.id)
2694    }
2695}
2696
2697impl Excerpt {
2698    fn new(
2699        id: ExcerptId,
2700        key: usize,
2701        buffer_id: usize,
2702        buffer: BufferSnapshot,
2703        range: ExcerptRange<text::Anchor>,
2704        has_trailing_newline: bool,
2705    ) -> Self {
2706        Excerpt {
2707            id,
2708            key,
2709            max_buffer_row: range.context.end.to_point(&buffer).row,
2710            text_summary: buffer
2711                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
2712            buffer_id,
2713            buffer,
2714            range,
2715            has_trailing_newline,
2716        }
2717    }
2718
2719    fn chunks_in_range<'a>(
2720        &'a self,
2721        range: Range<usize>,
2722        language_aware: bool,
2723    ) -> ExcerptChunks<'a> {
2724        let content_start = self.range.context.start.to_offset(&self.buffer);
2725        let chunks_start = content_start + range.start;
2726        let chunks_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2727
2728        let footer_height = if self.has_trailing_newline
2729            && range.start <= self.text_summary.bytes
2730            && range.end > self.text_summary.bytes
2731        {
2732            1
2733        } else {
2734            0
2735        };
2736
2737        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
2738
2739        ExcerptChunks {
2740            content_chunks,
2741            footer_height,
2742        }
2743    }
2744
2745    fn bytes_in_range(&self, range: Range<usize>) -> ExcerptBytes {
2746        let content_start = self.range.context.start.to_offset(&self.buffer);
2747        let bytes_start = content_start + range.start;
2748        let bytes_end = content_start + cmp::min(range.end, self.text_summary.bytes);
2749        let footer_height = if self.has_trailing_newline
2750            && range.start <= self.text_summary.bytes
2751            && range.end > self.text_summary.bytes
2752        {
2753            1
2754        } else {
2755            0
2756        };
2757        let content_bytes = self.buffer.bytes_in_range(bytes_start..bytes_end);
2758
2759        ExcerptBytes {
2760            content_bytes,
2761            footer_height,
2762        }
2763    }
2764
2765    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
2766        if text_anchor
2767            .cmp(&self.range.context.start, &self.buffer)
2768            .is_lt()
2769        {
2770            self.range.context.start.clone()
2771        } else if text_anchor
2772            .cmp(&self.range.context.end, &self.buffer)
2773            .is_gt()
2774        {
2775            self.range.context.end.clone()
2776        } else {
2777            text_anchor
2778        }
2779    }
2780
2781    fn contains(&self, anchor: &Anchor) -> bool {
2782        Some(self.buffer_id) == anchor.buffer_id
2783            && self
2784                .range
2785                .context
2786                .start
2787                .cmp(&anchor.text_anchor, &self.buffer)
2788                .is_le()
2789            && self
2790                .range
2791                .context
2792                .end
2793                .cmp(&anchor.text_anchor, &self.buffer)
2794                .is_ge()
2795    }
2796}
2797
2798impl fmt::Debug for Excerpt {
2799    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2800        f.debug_struct("Excerpt")
2801            .field("id", &self.id)
2802            .field("buffer_id", &self.buffer_id)
2803            .field("range", &self.range)
2804            .field("text_summary", &self.text_summary)
2805            .field("has_trailing_newline", &self.has_trailing_newline)
2806            .finish()
2807    }
2808}
2809
2810impl sum_tree::Item for Excerpt {
2811    type Summary = ExcerptSummary;
2812
2813    fn summary(&self) -> Self::Summary {
2814        let mut text = self.text_summary.clone();
2815        if self.has_trailing_newline {
2816            text += TextSummary::from("\n");
2817        }
2818        ExcerptSummary {
2819            excerpt_id: self.id.clone(),
2820            max_buffer_row: self.max_buffer_row,
2821            text,
2822        }
2823    }
2824}
2825
2826impl sum_tree::Summary for ExcerptSummary {
2827    type Context = ();
2828
2829    fn add_summary(&mut self, summary: &Self, _: &()) {
2830        debug_assert!(summary.excerpt_id > self.excerpt_id);
2831        self.excerpt_id = summary.excerpt_id.clone();
2832        self.text.add_summary(&summary.text, &());
2833        self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
2834    }
2835}
2836
2837impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for TextSummary {
2838    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2839        *self += &summary.text;
2840    }
2841}
2842
2843impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for usize {
2844    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2845        *self += summary.text.bytes;
2846    }
2847}
2848
2849impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for usize {
2850    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2851        Ord::cmp(self, &cursor_location.text.bytes)
2852    }
2853}
2854
2855impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, ExcerptSummary> for Option<&'a ExcerptId> {
2856    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
2857        Ord::cmp(self, &Some(&cursor_location.excerpt_id))
2858    }
2859}
2860
2861impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Point {
2862    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2863        *self += summary.text.lines;
2864    }
2865}
2866
2867impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for PointUtf16 {
2868    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2869        *self += summary.text.lines_utf16
2870    }
2871}
2872
2873impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a ExcerptId> {
2874    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
2875        *self = Some(&summary.excerpt_id);
2876    }
2877}
2878
2879impl<'a> MultiBufferRows<'a> {
2880    pub fn seek(&mut self, row: u32) {
2881        self.buffer_row_range = 0..0;
2882
2883        self.excerpts
2884            .seek_forward(&Point::new(row, 0), Bias::Right, &());
2885        if self.excerpts.item().is_none() {
2886            self.excerpts.prev(&());
2887
2888            if self.excerpts.item().is_none() && row == 0 {
2889                self.buffer_row_range = 0..1;
2890                return;
2891            }
2892        }
2893
2894        if let Some(excerpt) = self.excerpts.item() {
2895            let overshoot = row - self.excerpts.start().row;
2896            let excerpt_start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
2897            self.buffer_row_range.start = excerpt_start + overshoot;
2898            self.buffer_row_range.end = excerpt_start + excerpt.text_summary.lines.row + 1;
2899        }
2900    }
2901}
2902
2903impl<'a> Iterator for MultiBufferRows<'a> {
2904    type Item = Option<u32>;
2905
2906    fn next(&mut self) -> Option<Self::Item> {
2907        loop {
2908            if !self.buffer_row_range.is_empty() {
2909                let row = Some(self.buffer_row_range.start);
2910                self.buffer_row_range.start += 1;
2911                return Some(row);
2912            }
2913            self.excerpts.item()?;
2914            self.excerpts.next(&());
2915            let excerpt = self.excerpts.item()?;
2916            self.buffer_row_range.start = excerpt.range.context.start.to_point(&excerpt.buffer).row;
2917            self.buffer_row_range.end =
2918                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
2919        }
2920    }
2921}
2922
2923impl<'a> MultiBufferChunks<'a> {
2924    pub fn offset(&self) -> usize {
2925        self.range.start
2926    }
2927
2928    pub fn seek(&mut self, offset: usize) {
2929        self.range.start = offset;
2930        self.excerpts.seek(&offset, Bias::Right, &());
2931        if let Some(excerpt) = self.excerpts.item() {
2932            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2933                self.range.start - self.excerpts.start()..self.range.end - self.excerpts.start(),
2934                self.language_aware,
2935            ));
2936        } else {
2937            self.excerpt_chunks = None;
2938        }
2939    }
2940}
2941
2942impl<'a> Iterator for MultiBufferChunks<'a> {
2943    type Item = Chunk<'a>;
2944
2945    fn next(&mut self) -> Option<Self::Item> {
2946        if self.range.is_empty() {
2947            None
2948        } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
2949            self.range.start += chunk.text.len();
2950            Some(chunk)
2951        } else {
2952            self.excerpts.next(&());
2953            let excerpt = self.excerpts.item()?;
2954            self.excerpt_chunks = Some(excerpt.chunks_in_range(
2955                0..self.range.end - self.excerpts.start(),
2956                self.language_aware,
2957            ));
2958            self.next()
2959        }
2960    }
2961}
2962
2963impl<'a> MultiBufferBytes<'a> {
2964    fn consume(&mut self, len: usize) {
2965        self.range.start += len;
2966        self.chunk = &self.chunk[len..];
2967
2968        if !self.range.is_empty() && self.chunk.is_empty() {
2969            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
2970                self.chunk = chunk;
2971            } else {
2972                self.excerpts.next(&());
2973                if let Some(excerpt) = self.excerpts.item() {
2974                    let mut excerpt_bytes =
2975                        excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());
2976                    self.chunk = excerpt_bytes.next().unwrap();
2977                    self.excerpt_bytes = Some(excerpt_bytes);
2978                }
2979            }
2980        }
2981    }
2982}
2983
2984impl<'a> Iterator for MultiBufferBytes<'a> {
2985    type Item = &'a [u8];
2986
2987    fn next(&mut self) -> Option<Self::Item> {
2988        let chunk = self.chunk;
2989        if chunk.is_empty() {
2990            None
2991        } else {
2992            self.consume(chunk.len());
2993            Some(chunk)
2994        }
2995    }
2996}
2997
2998impl<'a> io::Read for MultiBufferBytes<'a> {
2999    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
3000        let len = cmp::min(buf.len(), self.chunk.len());
3001        buf[..len].copy_from_slice(&self.chunk[..len]);
3002        if len > 0 {
3003            self.consume(len);
3004        }
3005        Ok(len)
3006    }
3007}
3008
3009impl<'a> Iterator for ExcerptBytes<'a> {
3010    type Item = &'a [u8];
3011
3012    fn next(&mut self) -> Option<Self::Item> {
3013        if let Some(chunk) = self.content_bytes.next() {
3014            if !chunk.is_empty() {
3015                return Some(chunk);
3016            }
3017        }
3018
3019        if self.footer_height > 0 {
3020            let result = &NEWLINES[..self.footer_height];
3021            self.footer_height = 0;
3022            return Some(result);
3023        }
3024
3025        None
3026    }
3027}
3028
3029impl<'a> Iterator for ExcerptChunks<'a> {
3030    type Item = Chunk<'a>;
3031
3032    fn next(&mut self) -> Option<Self::Item> {
3033        if let Some(chunk) = self.content_chunks.next() {
3034            return Some(chunk);
3035        }
3036
3037        if self.footer_height > 0 {
3038            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
3039            self.footer_height = 0;
3040            return Some(Chunk {
3041                text,
3042                ..Default::default()
3043            });
3044        }
3045
3046        None
3047    }
3048}
3049
3050impl ToOffset for Point {
3051    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
3052        snapshot.point_to_offset(*self)
3053    }
3054}
3055
3056impl ToOffset for PointUtf16 {
3057    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
3058        snapshot.point_utf16_to_offset(*self)
3059    }
3060}
3061
3062impl ToOffset for usize {
3063    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
3064        assert!(*self <= snapshot.len(), "offset is out of range");
3065        *self
3066    }
3067}
3068
3069impl ToPoint for usize {
3070    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
3071        snapshot.offset_to_point(*self)
3072    }
3073}
3074
3075impl ToPoint for Point {
3076    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
3077        *self
3078    }
3079}
3080
3081impl ToPointUtf16 for usize {
3082    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
3083        snapshot.offset_to_point_utf16(*self)
3084    }
3085}
3086
3087impl ToPointUtf16 for Point {
3088    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
3089        snapshot.point_to_point_utf16(*self)
3090    }
3091}
3092
3093impl ToPointUtf16 for PointUtf16 {
3094    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
3095        *self
3096    }
3097}
3098
3099#[cfg(test)]
3100mod tests {
3101    use super::*;
3102    use gpui::MutableAppContext;
3103    use language::{Buffer, Rope};
3104    use rand::prelude::*;
3105    use std::{env, rc::Rc};
3106    use text::{Point, RandomCharIter};
3107    use util::test::sample_text;
3108
3109    #[gpui::test]
3110    fn test_singleton_multibuffer(cx: &mut MutableAppContext) {
3111        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
3112        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
3113
3114        let snapshot = multibuffer.read(cx).snapshot(cx);
3115        assert_eq!(snapshot.text(), buffer.read(cx).text());
3116
3117        assert_eq!(
3118            snapshot.buffer_rows(0).collect::<Vec<_>>(),
3119            (0..buffer.read(cx).row_count())
3120                .map(Some)
3121                .collect::<Vec<_>>()
3122        );
3123
3124        buffer.update(cx, |buffer, cx| buffer.edit([(1..3, "XXX\n")], cx));
3125        let snapshot = multibuffer.read(cx).snapshot(cx);
3126
3127        assert_eq!(snapshot.text(), buffer.read(cx).text());
3128        assert_eq!(
3129            snapshot.buffer_rows(0).collect::<Vec<_>>(),
3130            (0..buffer.read(cx).row_count())
3131                .map(Some)
3132                .collect::<Vec<_>>()
3133        );
3134    }
3135
3136    #[gpui::test]
3137    fn test_remote_multibuffer(cx: &mut MutableAppContext) {
3138        let host_buffer = cx.add_model(|cx| Buffer::new(0, "a", cx));
3139        let guest_buffer = cx.add_model(|cx| {
3140            let message = host_buffer.read(cx).to_proto();
3141            Buffer::from_proto(1, message, None, cx).unwrap()
3142        });
3143        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(guest_buffer.clone(), cx));
3144        let snapshot = multibuffer.read(cx).snapshot(cx);
3145        assert_eq!(snapshot.text(), "a");
3146
3147        guest_buffer.update(cx, |buffer, cx| buffer.edit([(1..1, "b")], cx));
3148        let snapshot = multibuffer.read(cx).snapshot(cx);
3149        assert_eq!(snapshot.text(), "ab");
3150
3151        guest_buffer.update(cx, |buffer, cx| buffer.edit([(2..2, "c")], cx));
3152        let snapshot = multibuffer.read(cx).snapshot(cx);
3153        assert_eq!(snapshot.text(), "abc");
3154    }
3155
3156    #[gpui::test]
3157    fn test_excerpt_buffer(cx: &mut MutableAppContext) {
3158        let buffer_1 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'a'), cx));
3159        let buffer_2 = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6, 'g'), cx));
3160        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3161
3162        let events = Rc::new(RefCell::new(Vec::<Event>::new()));
3163        multibuffer.update(cx, |_, cx| {
3164            let events = events.clone();
3165            cx.subscribe(&multibuffer, move |_, _, event, _| {
3166                events.borrow_mut().push(event.clone())
3167            })
3168            .detach();
3169        });
3170
3171        let subscription = multibuffer.update(cx, |multibuffer, cx| {
3172            let subscription = multibuffer.subscribe();
3173            multibuffer.push_excerpts(
3174                buffer_1.clone(),
3175                [ExcerptRange {
3176                    context: Point::new(1, 2)..Point::new(2, 5),
3177                    primary: None,
3178                }],
3179                cx,
3180            );
3181            assert_eq!(
3182                subscription.consume().into_inner(),
3183                [Edit {
3184                    old: 0..0,
3185                    new: 0..10
3186                }]
3187            );
3188
3189            multibuffer.push_excerpts(
3190                buffer_1.clone(),
3191                [ExcerptRange {
3192                    context: Point::new(3, 3)..Point::new(4, 4),
3193                    primary: None,
3194                }],
3195                cx,
3196            );
3197            multibuffer.push_excerpts(
3198                buffer_2.clone(),
3199                [ExcerptRange {
3200                    context: Point::new(3, 1)..Point::new(3, 3),
3201                    primary: None,
3202                }],
3203                cx,
3204            );
3205            assert_eq!(
3206                subscription.consume().into_inner(),
3207                [Edit {
3208                    old: 10..10,
3209                    new: 10..22
3210                }]
3211            );
3212
3213            subscription
3214        });
3215
3216        // Adding excerpts emits an edited event.
3217        assert_eq!(
3218            events.borrow().as_slice(),
3219            &[Event::Edited, Event::Edited, Event::Edited]
3220        );
3221
3222        let snapshot = multibuffer.read(cx).snapshot(cx);
3223        assert_eq!(
3224            snapshot.text(),
3225            concat!(
3226                "bbbb\n",  // Preserve newlines
3227                "ccccc\n", //
3228                "ddd\n",   //
3229                "eeee\n",  //
3230                "jj"       //
3231            )
3232        );
3233        assert_eq!(
3234            snapshot.buffer_rows(0).collect::<Vec<_>>(),
3235            [Some(1), Some(2), Some(3), Some(4), Some(3)]
3236        );
3237        assert_eq!(
3238            snapshot.buffer_rows(2).collect::<Vec<_>>(),
3239            [Some(3), Some(4), Some(3)]
3240        );
3241        assert_eq!(snapshot.buffer_rows(4).collect::<Vec<_>>(), [Some(3)]);
3242        assert_eq!(snapshot.buffer_rows(5).collect::<Vec<_>>(), []);
3243
3244        assert_eq!(
3245            boundaries_in_range(Point::new(0, 0)..Point::new(4, 2), &snapshot),
3246            &[
3247                (0, "bbbb\nccccc".to_string(), true),
3248                (2, "ddd\neeee".to_string(), false),
3249                (4, "jj".to_string(), true),
3250            ]
3251        );
3252        assert_eq!(
3253            boundaries_in_range(Point::new(0, 0)..Point::new(2, 0), &snapshot),
3254            &[(0, "bbbb\nccccc".to_string(), true)]
3255        );
3256        assert_eq!(
3257            boundaries_in_range(Point::new(1, 0)..Point::new(1, 5), &snapshot),
3258            &[]
3259        );
3260        assert_eq!(
3261            boundaries_in_range(Point::new(1, 0)..Point::new(2, 0), &snapshot),
3262            &[]
3263        );
3264        assert_eq!(
3265            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
3266            &[(2, "ddd\neeee".to_string(), false)]
3267        );
3268        assert_eq!(
3269            boundaries_in_range(Point::new(1, 0)..Point::new(4, 0), &snapshot),
3270            &[(2, "ddd\neeee".to_string(), false)]
3271        );
3272        assert_eq!(
3273            boundaries_in_range(Point::new(2, 0)..Point::new(3, 0), &snapshot),
3274            &[(2, "ddd\neeee".to_string(), false)]
3275        );
3276        assert_eq!(
3277            boundaries_in_range(Point::new(4, 0)..Point::new(4, 2), &snapshot),
3278            &[(4, "jj".to_string(), true)]
3279        );
3280        assert_eq!(
3281            boundaries_in_range(Point::new(4, 2)..Point::new(4, 2), &snapshot),
3282            &[]
3283        );
3284
3285        buffer_1.update(cx, |buffer, cx| {
3286            let text = "\n";
3287            buffer.edit(
3288                [
3289                    (Point::new(0, 0)..Point::new(0, 0), text),
3290                    (Point::new(2, 1)..Point::new(2, 3), text),
3291                ],
3292                cx,
3293            );
3294        });
3295
3296        let snapshot = multibuffer.read(cx).snapshot(cx);
3297        assert_eq!(
3298            snapshot.text(),
3299            concat!(
3300                "bbbb\n", // Preserve newlines
3301                "c\n",    //
3302                "cc\n",   //
3303                "ddd\n",  //
3304                "eeee\n", //
3305                "jj"      //
3306            )
3307        );
3308
3309        assert_eq!(
3310            subscription.consume().into_inner(),
3311            [Edit {
3312                old: 6..8,
3313                new: 6..7
3314            }]
3315        );
3316
3317        let snapshot = multibuffer.read(cx).snapshot(cx);
3318        assert_eq!(
3319            snapshot.clip_point(Point::new(0, 5), Bias::Left),
3320            Point::new(0, 4)
3321        );
3322        assert_eq!(
3323            snapshot.clip_point(Point::new(0, 5), Bias::Right),
3324            Point::new(0, 4)
3325        );
3326        assert_eq!(
3327            snapshot.clip_point(Point::new(5, 1), Bias::Right),
3328            Point::new(5, 1)
3329        );
3330        assert_eq!(
3331            snapshot.clip_point(Point::new(5, 2), Bias::Right),
3332            Point::new(5, 2)
3333        );
3334        assert_eq!(
3335            snapshot.clip_point(Point::new(5, 3), Bias::Right),
3336            Point::new(5, 2)
3337        );
3338
3339        let snapshot = multibuffer.update(cx, |multibuffer, cx| {
3340            let (buffer_2_excerpt_id, _) =
3341                multibuffer.excerpts_for_buffer(&buffer_2, cx)[0].clone();
3342            multibuffer.remove_excerpts(&[buffer_2_excerpt_id], cx);
3343            multibuffer.snapshot(cx)
3344        });
3345
3346        assert_eq!(
3347            snapshot.text(),
3348            concat!(
3349                "bbbb\n", // Preserve newlines
3350                "c\n",    //
3351                "cc\n",   //
3352                "ddd\n",  //
3353                "eeee",   //
3354            )
3355        );
3356
3357        fn boundaries_in_range(
3358            range: Range<Point>,
3359            snapshot: &MultiBufferSnapshot,
3360        ) -> Vec<(u32, String, bool)> {
3361            snapshot
3362                .excerpt_boundaries_in_range(range)
3363                .map(|boundary| {
3364                    (
3365                        boundary.row,
3366                        boundary
3367                            .buffer
3368                            .text_for_range(boundary.range.context)
3369                            .collect::<String>(),
3370                        boundary.starts_new_buffer,
3371                    )
3372                })
3373                .collect::<Vec<_>>()
3374        }
3375    }
3376
3377    #[gpui::test]
3378    fn test_excerpts_with_context_lines(cx: &mut MutableAppContext) {
3379        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(20, 3, 'a'), cx));
3380        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3381        let anchor_ranges = multibuffer.update(cx, |multibuffer, cx| {
3382            multibuffer.push_excerpts_with_context_lines(
3383                buffer.clone(),
3384                vec![
3385                    Point::new(3, 2)..Point::new(4, 2),
3386                    Point::new(7, 1)..Point::new(7, 3),
3387                    Point::new(15, 0)..Point::new(15, 0),
3388                ],
3389                2,
3390                cx,
3391            )
3392        });
3393
3394        let snapshot = multibuffer.read(cx).snapshot(cx);
3395        assert_eq!(
3396            snapshot.text(),
3397            "bbb\nccc\nddd\neee\nfff\nggg\nhhh\niii\njjj\n\nnnn\nooo\nppp\nqqq\nrrr\n"
3398        );
3399
3400        assert_eq!(
3401            anchor_ranges
3402                .iter()
3403                .map(|range| range.to_point(&snapshot))
3404                .collect::<Vec<_>>(),
3405            vec![
3406                Point::new(2, 2)..Point::new(3, 2),
3407                Point::new(6, 1)..Point::new(6, 3),
3408                Point::new(12, 0)..Point::new(12, 0)
3409            ]
3410        );
3411    }
3412
3413    #[gpui::test]
3414    fn test_empty_excerpt_buffer(cx: &mut MutableAppContext) {
3415        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3416
3417        let snapshot = multibuffer.read(cx).snapshot(cx);
3418        assert_eq!(snapshot.text(), "");
3419        assert_eq!(snapshot.buffer_rows(0).collect::<Vec<_>>(), &[Some(0)]);
3420        assert_eq!(snapshot.buffer_rows(1).collect::<Vec<_>>(), &[]);
3421    }
3422
3423    #[gpui::test]
3424    fn test_singleton_multibuffer_anchors(cx: &mut MutableAppContext) {
3425        let buffer = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3426        let multibuffer = cx.add_model(|cx| MultiBuffer::singleton(buffer.clone(), cx));
3427        let old_snapshot = multibuffer.read(cx).snapshot(cx);
3428        buffer.update(cx, |buffer, cx| {
3429            buffer.edit([(0..0, "X")], cx);
3430            buffer.edit([(5..5, "Y")], cx);
3431        });
3432        let new_snapshot = multibuffer.read(cx).snapshot(cx);
3433
3434        assert_eq!(old_snapshot.text(), "abcd");
3435        assert_eq!(new_snapshot.text(), "XabcdY");
3436
3437        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
3438        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
3439        assert_eq!(old_snapshot.anchor_before(4).to_offset(&new_snapshot), 5);
3440        assert_eq!(old_snapshot.anchor_after(4).to_offset(&new_snapshot), 6);
3441    }
3442
3443    #[gpui::test]
3444    fn test_multibuffer_anchors(cx: &mut MutableAppContext) {
3445        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3446        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "efghi", cx));
3447        let multibuffer = cx.add_model(|cx| {
3448            let mut multibuffer = MultiBuffer::new(0);
3449            multibuffer.push_excerpts(
3450                buffer_1.clone(),
3451                [ExcerptRange {
3452                    context: 0..4,
3453                    primary: None,
3454                }],
3455                cx,
3456            );
3457            multibuffer.push_excerpts(
3458                buffer_2.clone(),
3459                [ExcerptRange {
3460                    context: 0..5,
3461                    primary: None,
3462                }],
3463                cx,
3464            );
3465            multibuffer
3466        });
3467        let old_snapshot = multibuffer.read(cx).snapshot(cx);
3468
3469        assert_eq!(old_snapshot.anchor_before(0).to_offset(&old_snapshot), 0);
3470        assert_eq!(old_snapshot.anchor_after(0).to_offset(&old_snapshot), 0);
3471        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
3472        assert_eq!(Anchor::min().to_offset(&old_snapshot), 0);
3473        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
3474        assert_eq!(Anchor::max().to_offset(&old_snapshot), 10);
3475
3476        buffer_1.update(cx, |buffer, cx| {
3477            buffer.edit([(0..0, "W")], cx);
3478            buffer.edit([(5..5, "X")], cx);
3479        });
3480        buffer_2.update(cx, |buffer, cx| {
3481            buffer.edit([(0..0, "Y")], cx);
3482            buffer.edit([(6..6, "Z")], cx);
3483        });
3484        let new_snapshot = multibuffer.read(cx).snapshot(cx);
3485
3486        assert_eq!(old_snapshot.text(), "abcd\nefghi");
3487        assert_eq!(new_snapshot.text(), "WabcdX\nYefghiZ");
3488
3489        assert_eq!(old_snapshot.anchor_before(0).to_offset(&new_snapshot), 0);
3490        assert_eq!(old_snapshot.anchor_after(0).to_offset(&new_snapshot), 1);
3491        assert_eq!(old_snapshot.anchor_before(1).to_offset(&new_snapshot), 2);
3492        assert_eq!(old_snapshot.anchor_after(1).to_offset(&new_snapshot), 2);
3493        assert_eq!(old_snapshot.anchor_before(2).to_offset(&new_snapshot), 3);
3494        assert_eq!(old_snapshot.anchor_after(2).to_offset(&new_snapshot), 3);
3495        assert_eq!(old_snapshot.anchor_before(5).to_offset(&new_snapshot), 7);
3496        assert_eq!(old_snapshot.anchor_after(5).to_offset(&new_snapshot), 8);
3497        assert_eq!(old_snapshot.anchor_before(10).to_offset(&new_snapshot), 13);
3498        assert_eq!(old_snapshot.anchor_after(10).to_offset(&new_snapshot), 14);
3499    }
3500
3501    #[gpui::test]
3502    fn test_multibuffer_resolving_anchors_after_replacing_their_excerpts(
3503        cx: &mut MutableAppContext,
3504    ) {
3505        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "abcd", cx));
3506        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "ABCDEFGHIJKLMNOP", cx));
3507        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3508
3509        // Create an insertion id in buffer 1 that doesn't exist in buffer 2.
3510        // Add an excerpt from buffer 1 that spans this new insertion.
3511        buffer_1.update(cx, |buffer, cx| buffer.edit([(4..4, "123")], cx));
3512        let excerpt_id_1 = multibuffer.update(cx, |multibuffer, cx| {
3513            multibuffer
3514                .push_excerpts(
3515                    buffer_1.clone(),
3516                    [ExcerptRange {
3517                        context: 0..7,
3518                        primary: None,
3519                    }],
3520                    cx,
3521                )
3522                .pop()
3523                .unwrap()
3524        });
3525
3526        let snapshot_1 = multibuffer.read(cx).snapshot(cx);
3527        assert_eq!(snapshot_1.text(), "abcd123");
3528
3529        // Replace the buffer 1 excerpt with new excerpts from buffer 2.
3530        let (excerpt_id_2, excerpt_id_3) = multibuffer.update(cx, |multibuffer, cx| {
3531            multibuffer.remove_excerpts([&excerpt_id_1], cx);
3532            let mut ids = multibuffer
3533                .push_excerpts(
3534                    buffer_2.clone(),
3535                    [
3536                        ExcerptRange {
3537                            context: 0..4,
3538                            primary: None,
3539                        },
3540                        ExcerptRange {
3541                            context: 6..10,
3542                            primary: None,
3543                        },
3544                        ExcerptRange {
3545                            context: 12..16,
3546                            primary: None,
3547                        },
3548                    ],
3549                    cx,
3550                )
3551                .into_iter();
3552            (ids.next().unwrap(), ids.next().unwrap())
3553        });
3554        let snapshot_2 = multibuffer.read(cx).snapshot(cx);
3555        assert_eq!(snapshot_2.text(), "ABCD\nGHIJ\nMNOP");
3556
3557        // The old excerpt id doesn't get reused.
3558        assert_ne!(excerpt_id_2, excerpt_id_1);
3559
3560        // Resolve some anchors from the previous snapshot in the new snapshot.
3561        // Although there is still an excerpt with the same id, it is for
3562        // a different buffer, so we don't attempt to resolve the old text
3563        // anchor in the new buffer.
3564        assert_eq!(
3565            snapshot_2.summary_for_anchor::<usize>(&snapshot_1.anchor_before(2)),
3566            0
3567        );
3568        assert_eq!(
3569            snapshot_2.summaries_for_anchors::<usize, _>(&[
3570                snapshot_1.anchor_before(2),
3571                snapshot_1.anchor_after(3)
3572            ]),
3573            vec![0, 0]
3574        );
3575        let refresh =
3576            snapshot_2.refresh_anchors(&[snapshot_1.anchor_before(2), snapshot_1.anchor_after(3)]);
3577        assert_eq!(
3578            refresh,
3579            &[
3580                (0, snapshot_2.anchor_before(0), false),
3581                (1, snapshot_2.anchor_after(0), false),
3582            ]
3583        );
3584
3585        // Replace the middle excerpt with a smaller excerpt in buffer 2,
3586        // that intersects the old excerpt.
3587        let excerpt_id_5 = multibuffer.update(cx, |multibuffer, cx| {
3588            multibuffer.remove_excerpts([&excerpt_id_3], cx);
3589            multibuffer
3590                .insert_excerpts_after(
3591                    &excerpt_id_3,
3592                    buffer_2.clone(),
3593                    [ExcerptRange {
3594                        context: 5..8,
3595                        primary: None,
3596                    }],
3597                    cx,
3598                )
3599                .pop()
3600                .unwrap()
3601        });
3602
3603        let snapshot_3 = multibuffer.read(cx).snapshot(cx);
3604        assert_eq!(snapshot_3.text(), "ABCD\nFGH\nMNOP");
3605        assert_ne!(excerpt_id_5, excerpt_id_3);
3606
3607        // Resolve some anchors from the previous snapshot in the new snapshot.
3608        // The anchor in the middle excerpt snaps to the beginning of the
3609        // excerpt, since it is not
3610        let anchors = [
3611            snapshot_2.anchor_before(0),
3612            snapshot_2.anchor_after(2),
3613            snapshot_2.anchor_after(6),
3614            snapshot_2.anchor_after(14),
3615        ];
3616        assert_eq!(
3617            snapshot_3.summaries_for_anchors::<usize, _>(&anchors),
3618            &[0, 2, 5, 13]
3619        );
3620
3621        let new_anchors = snapshot_3.refresh_anchors(&anchors);
3622        assert_eq!(
3623            new_anchors.iter().map(|a| (a.0, a.2)).collect::<Vec<_>>(),
3624            &[(0, true), (1, true), (2, true), (3, true)]
3625        );
3626        assert_eq!(
3627            snapshot_3.summaries_for_anchors::<usize, _>(new_anchors.iter().map(|a| &a.1)),
3628            &[0, 2, 7, 13]
3629        );
3630    }
3631
3632    #[gpui::test(iterations = 100)]
3633    fn test_random_multibuffer(cx: &mut MutableAppContext, mut rng: StdRng) {
3634        let operations = env::var("OPERATIONS")
3635            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
3636            .unwrap_or(10);
3637
3638        let mut buffers: Vec<ModelHandle<Buffer>> = Vec::new();
3639        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
3640        let mut excerpt_ids = Vec::new();
3641        let mut expected_excerpts = Vec::<(ModelHandle<Buffer>, Range<text::Anchor>)>::new();
3642        let mut anchors = Vec::new();
3643        let mut old_versions = Vec::new();
3644
3645        for _ in 0..operations {
3646            match rng.gen_range(0..100) {
3647                0..=19 if !buffers.is_empty() => {
3648                    let buffer = buffers.choose(&mut rng).unwrap();
3649                    buffer.update(cx, |buf, cx| buf.randomly_edit(&mut rng, 5, cx));
3650                }
3651                20..=29 if !expected_excerpts.is_empty() => {
3652                    let mut ids_to_remove = vec![];
3653                    for _ in 0..rng.gen_range(1..=3) {
3654                        if expected_excerpts.is_empty() {
3655                            break;
3656                        }
3657
3658                        let ix = rng.gen_range(0..expected_excerpts.len());
3659                        ids_to_remove.push(excerpt_ids.remove(ix));
3660                        let (buffer, range) = expected_excerpts.remove(ix);
3661                        let buffer = buffer.read(cx);
3662                        log::info!(
3663                            "Removing excerpt {}: {:?}",
3664                            ix,
3665                            buffer
3666                                .text_for_range(range.to_offset(&buffer))
3667                                .collect::<String>(),
3668                        );
3669                    }
3670                    ids_to_remove.sort_unstable();
3671                    multibuffer.update(cx, |multibuffer, cx| {
3672                        multibuffer.remove_excerpts(&ids_to_remove, cx)
3673                    });
3674                }
3675                30..=39 if !expected_excerpts.is_empty() => {
3676                    let multibuffer = multibuffer.read(cx).read(cx);
3677                    let offset =
3678                        multibuffer.clip_offset(rng.gen_range(0..=multibuffer.len()), Bias::Left);
3679                    let bias = if rng.gen() { Bias::Left } else { Bias::Right };
3680                    log::info!("Creating anchor at {} with bias {:?}", offset, bias);
3681                    anchors.push(multibuffer.anchor_at(offset, bias));
3682                    anchors.sort_by(|a, b| a.cmp(&b, &multibuffer));
3683                }
3684                40..=44 if !anchors.is_empty() => {
3685                    let multibuffer = multibuffer.read(cx).read(cx);
3686                    let prev_len = anchors.len();
3687                    anchors = multibuffer
3688                        .refresh_anchors(&anchors)
3689                        .into_iter()
3690                        .map(|a| a.1)
3691                        .collect();
3692
3693                    // Ensure the newly-refreshed anchors point to a valid excerpt and don't
3694                    // overshoot its boundaries.
3695                    assert_eq!(anchors.len(), prev_len);
3696                    let mut cursor = multibuffer.excerpts.cursor::<Option<&ExcerptId>>();
3697                    for anchor in &anchors {
3698                        if anchor.excerpt_id == ExcerptId::min()
3699                            || anchor.excerpt_id == ExcerptId::max()
3700                        {
3701                            continue;
3702                        }
3703
3704                        cursor.seek_forward(&Some(&anchor.excerpt_id), Bias::Left, &());
3705                        let excerpt = cursor.item().unwrap();
3706                        assert_eq!(excerpt.id, anchor.excerpt_id);
3707                        assert!(excerpt.contains(anchor));
3708                    }
3709                }
3710                _ => {
3711                    let buffer_handle = if buffers.is_empty() || rng.gen_bool(0.4) {
3712                        let base_text = RandomCharIter::new(&mut rng).take(10).collect::<String>();
3713                        buffers.push(cx.add_model(|cx| Buffer::new(0, base_text, cx)));
3714                        buffers.last().unwrap()
3715                    } else {
3716                        buffers.choose(&mut rng).unwrap()
3717                    };
3718
3719                    let buffer = buffer_handle.read(cx);
3720                    let end_ix = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3721                    let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3722                    let anchor_range = buffer.anchor_before(start_ix)..buffer.anchor_after(end_ix);
3723                    let prev_excerpt_ix = rng.gen_range(0..=expected_excerpts.len());
3724                    let prev_excerpt_id = excerpt_ids
3725                        .get(prev_excerpt_ix)
3726                        .cloned()
3727                        .unwrap_or(ExcerptId::max());
3728                    let excerpt_ix = (prev_excerpt_ix + 1).min(expected_excerpts.len());
3729
3730                    log::info!(
3731                        "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
3732                        excerpt_ix,
3733                        expected_excerpts.len(),
3734                        buffer_handle.id(),
3735                        buffer.text(),
3736                        start_ix..end_ix,
3737                        &buffer.text()[start_ix..end_ix]
3738                    );
3739
3740                    let excerpt_id = multibuffer.update(cx, |multibuffer, cx| {
3741                        multibuffer
3742                            .insert_excerpts_after(
3743                                &prev_excerpt_id,
3744                                buffer_handle.clone(),
3745                                [ExcerptRange {
3746                                    context: start_ix..end_ix,
3747                                    primary: None,
3748                                }],
3749                                cx,
3750                            )
3751                            .pop()
3752                            .unwrap()
3753                    });
3754
3755                    excerpt_ids.insert(excerpt_ix, excerpt_id);
3756                    expected_excerpts.insert(excerpt_ix, (buffer_handle.clone(), anchor_range));
3757                }
3758            }
3759
3760            if rng.gen_bool(0.3) {
3761                multibuffer.update(cx, |multibuffer, cx| {
3762                    old_versions.push((multibuffer.snapshot(cx), multibuffer.subscribe()));
3763                })
3764            }
3765
3766            let snapshot = multibuffer.read(cx).snapshot(cx);
3767
3768            let mut excerpt_starts = Vec::new();
3769            let mut expected_text = String::new();
3770            let mut expected_buffer_rows = Vec::new();
3771            for (buffer, range) in &expected_excerpts {
3772                let buffer = buffer.read(cx);
3773                let buffer_range = range.to_offset(buffer);
3774
3775                excerpt_starts.push(TextSummary::from(expected_text.as_str()));
3776                expected_text.extend(buffer.text_for_range(buffer_range.clone()));
3777                expected_text.push('\n');
3778
3779                let buffer_row_range = buffer.offset_to_point(buffer_range.start).row
3780                    ..=buffer.offset_to_point(buffer_range.end).row;
3781                for row in buffer_row_range {
3782                    expected_buffer_rows.push(Some(row));
3783                }
3784            }
3785            // Remove final trailing newline.
3786            if !expected_excerpts.is_empty() {
3787                expected_text.pop();
3788            }
3789
3790            // Always report one buffer row
3791            if expected_buffer_rows.is_empty() {
3792                expected_buffer_rows.push(Some(0));
3793            }
3794
3795            assert_eq!(snapshot.text(), expected_text);
3796            log::info!("MultiBuffer text: {:?}", expected_text);
3797
3798            assert_eq!(
3799                snapshot.buffer_rows(0).collect::<Vec<_>>(),
3800                expected_buffer_rows,
3801            );
3802
3803            for _ in 0..5 {
3804                let start_row = rng.gen_range(0..=expected_buffer_rows.len());
3805                assert_eq!(
3806                    snapshot.buffer_rows(start_row as u32).collect::<Vec<_>>(),
3807                    &expected_buffer_rows[start_row..],
3808                    "buffer_rows({})",
3809                    start_row
3810                );
3811            }
3812
3813            assert_eq!(
3814                snapshot.max_buffer_row(),
3815                expected_buffer_rows
3816                    .into_iter()
3817                    .filter_map(|r| r)
3818                    .max()
3819                    .unwrap()
3820            );
3821
3822            let mut excerpt_starts = excerpt_starts.into_iter();
3823            for (buffer, range) in &expected_excerpts {
3824                let buffer_id = buffer.id();
3825                let buffer = buffer.read(cx);
3826                let buffer_range = range.to_offset(buffer);
3827                let buffer_start_point = buffer.offset_to_point(buffer_range.start);
3828                let buffer_start_point_utf16 =
3829                    buffer.text_summary_for_range::<PointUtf16, _>(0..buffer_range.start);
3830
3831                let excerpt_start = excerpt_starts.next().unwrap();
3832                let mut offset = excerpt_start.bytes;
3833                let mut buffer_offset = buffer_range.start;
3834                let mut point = excerpt_start.lines;
3835                let mut buffer_point = buffer_start_point;
3836                let mut point_utf16 = excerpt_start.lines_utf16;
3837                let mut buffer_point_utf16 = buffer_start_point_utf16;
3838                for ch in buffer
3839                    .snapshot()
3840                    .chunks(buffer_range.clone(), false)
3841                    .flat_map(|c| c.text.chars())
3842                {
3843                    for _ in 0..ch.len_utf8() {
3844                        let left_offset = snapshot.clip_offset(offset, Bias::Left);
3845                        let right_offset = snapshot.clip_offset(offset, Bias::Right);
3846                        let buffer_left_offset = buffer.clip_offset(buffer_offset, Bias::Left);
3847                        let buffer_right_offset = buffer.clip_offset(buffer_offset, Bias::Right);
3848                        assert_eq!(
3849                            left_offset,
3850                            excerpt_start.bytes + (buffer_left_offset - buffer_range.start),
3851                            "clip_offset({:?}, Left). buffer: {:?}, buffer offset: {:?}",
3852                            offset,
3853                            buffer_id,
3854                            buffer_offset,
3855                        );
3856                        assert_eq!(
3857                            right_offset,
3858                            excerpt_start.bytes + (buffer_right_offset - buffer_range.start),
3859                            "clip_offset({:?}, Right). buffer: {:?}, buffer offset: {:?}",
3860                            offset,
3861                            buffer_id,
3862                            buffer_offset,
3863                        );
3864
3865                        let left_point = snapshot.clip_point(point, Bias::Left);
3866                        let right_point = snapshot.clip_point(point, Bias::Right);
3867                        let buffer_left_point = buffer.clip_point(buffer_point, Bias::Left);
3868                        let buffer_right_point = buffer.clip_point(buffer_point, Bias::Right);
3869                        assert_eq!(
3870                            left_point,
3871                            excerpt_start.lines + (buffer_left_point - buffer_start_point),
3872                            "clip_point({:?}, Left). buffer: {:?}, buffer point: {:?}",
3873                            point,
3874                            buffer_id,
3875                            buffer_point,
3876                        );
3877                        assert_eq!(
3878                            right_point,
3879                            excerpt_start.lines + (buffer_right_point - buffer_start_point),
3880                            "clip_point({:?}, Right). buffer: {:?}, buffer point: {:?}",
3881                            point,
3882                            buffer_id,
3883                            buffer_point,
3884                        );
3885
3886                        assert_eq!(
3887                            snapshot.point_to_offset(left_point),
3888                            left_offset,
3889                            "point_to_offset({:?})",
3890                            left_point,
3891                        );
3892                        assert_eq!(
3893                            snapshot.offset_to_point(left_offset),
3894                            left_point,
3895                            "offset_to_point({:?})",
3896                            left_offset,
3897                        );
3898
3899                        offset += 1;
3900                        buffer_offset += 1;
3901                        if ch == '\n' {
3902                            point += Point::new(1, 0);
3903                            buffer_point += Point::new(1, 0);
3904                        } else {
3905                            point += Point::new(0, 1);
3906                            buffer_point += Point::new(0, 1);
3907                        }
3908                    }
3909
3910                    for _ in 0..ch.len_utf16() {
3911                        let left_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Left);
3912                        let right_point_utf16 = snapshot.clip_point_utf16(point_utf16, Bias::Right);
3913                        let buffer_left_point_utf16 =
3914                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Left);
3915                        let buffer_right_point_utf16 =
3916                            buffer.clip_point_utf16(buffer_point_utf16, Bias::Right);
3917                        assert_eq!(
3918                            left_point_utf16,
3919                            excerpt_start.lines_utf16
3920                                + (buffer_left_point_utf16 - buffer_start_point_utf16),
3921                            "clip_point_utf16({:?}, Left). buffer: {:?}, buffer point_utf16: {:?}",
3922                            point_utf16,
3923                            buffer_id,
3924                            buffer_point_utf16,
3925                        );
3926                        assert_eq!(
3927                            right_point_utf16,
3928                            excerpt_start.lines_utf16
3929                                + (buffer_right_point_utf16 - buffer_start_point_utf16),
3930                            "clip_point_utf16({:?}, Right). buffer: {:?}, buffer point_utf16: {:?}",
3931                            point_utf16,
3932                            buffer_id,
3933                            buffer_point_utf16,
3934                        );
3935
3936                        if ch == '\n' {
3937                            point_utf16 += PointUtf16::new(1, 0);
3938                            buffer_point_utf16 += PointUtf16::new(1, 0);
3939                        } else {
3940                            point_utf16 += PointUtf16::new(0, 1);
3941                            buffer_point_utf16 += PointUtf16::new(0, 1);
3942                        }
3943                    }
3944                }
3945            }
3946
3947            for (row, line) in expected_text.split('\n').enumerate() {
3948                assert_eq!(
3949                    snapshot.line_len(row as u32),
3950                    line.len() as u32,
3951                    "line_len({}).",
3952                    row
3953                );
3954            }
3955
3956            let text_rope = Rope::from(expected_text.as_str());
3957            for _ in 0..10 {
3958                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
3959                let start_ix = text_rope.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3960
3961                let text_for_range = snapshot
3962                    .text_for_range(start_ix..end_ix)
3963                    .collect::<String>();
3964                assert_eq!(
3965                    text_for_range,
3966                    &expected_text[start_ix..end_ix],
3967                    "incorrect text for range {:?}",
3968                    start_ix..end_ix
3969                );
3970
3971                let excerpted_buffer_ranges = multibuffer
3972                    .read(cx)
3973                    .range_to_buffer_ranges(start_ix..end_ix, cx);
3974                let excerpted_buffers_text = excerpted_buffer_ranges
3975                    .into_iter()
3976                    .map(|(buffer, buffer_range)| {
3977                        buffer
3978                            .read(cx)
3979                            .text_for_range(buffer_range)
3980                            .collect::<String>()
3981                    })
3982                    .collect::<Vec<_>>()
3983                    .join("\n");
3984                assert_eq!(excerpted_buffers_text, text_for_range);
3985
3986                let expected_summary = TextSummary::from(&expected_text[start_ix..end_ix]);
3987                assert_eq!(
3988                    snapshot.text_summary_for_range::<TextSummary, _>(start_ix..end_ix),
3989                    expected_summary,
3990                    "incorrect summary for range {:?}",
3991                    start_ix..end_ix
3992                );
3993            }
3994
3995            // Anchor resolution
3996            let summaries = snapshot.summaries_for_anchors::<usize, _>(&anchors);
3997            assert_eq!(anchors.len(), summaries.len());
3998            for (anchor, resolved_offset) in anchors.iter().zip(summaries) {
3999                assert!(resolved_offset <= snapshot.len());
4000                assert_eq!(
4001                    snapshot.summary_for_anchor::<usize>(anchor),
4002                    resolved_offset
4003                );
4004            }
4005
4006            for _ in 0..10 {
4007                let end_ix = text_rope.clip_offset(rng.gen_range(0..=text_rope.len()), Bias::Right);
4008                assert_eq!(
4009                    snapshot.reversed_chars_at(end_ix).collect::<String>(),
4010                    expected_text[..end_ix].chars().rev().collect::<String>(),
4011                );
4012            }
4013
4014            for _ in 0..10 {
4015                let end_ix = rng.gen_range(0..=text_rope.len());
4016                let start_ix = rng.gen_range(0..=end_ix);
4017                assert_eq!(
4018                    snapshot
4019                        .bytes_in_range(start_ix..end_ix)
4020                        .flatten()
4021                        .copied()
4022                        .collect::<Vec<_>>(),
4023                    expected_text.as_bytes()[start_ix..end_ix].to_vec(),
4024                    "bytes_in_range({:?})",
4025                    start_ix..end_ix,
4026                );
4027            }
4028        }
4029
4030        let snapshot = multibuffer.read(cx).snapshot(cx);
4031        for (old_snapshot, subscription) in old_versions {
4032            let edits = subscription.consume().into_inner();
4033
4034            log::info!(
4035                "applying subscription edits to old text: {:?}: {:?}",
4036                old_snapshot.text(),
4037                edits,
4038            );
4039
4040            let mut text = old_snapshot.text();
4041            for edit in edits {
4042                let new_text: String = snapshot.text_for_range(edit.new.clone()).collect();
4043                text.replace_range(edit.new.start..edit.new.start + edit.old.len(), &new_text);
4044            }
4045            assert_eq!(text.to_string(), snapshot.text());
4046        }
4047    }
4048
4049    #[gpui::test]
4050    fn test_history(cx: &mut MutableAppContext) {
4051        cx.set_global(Settings::test(cx));
4052        let buffer_1 = cx.add_model(|cx| Buffer::new(0, "1234", cx));
4053        let buffer_2 = cx.add_model(|cx| Buffer::new(0, "5678", cx));
4054        let multibuffer = cx.add_model(|_| MultiBuffer::new(0));
4055        let group_interval = multibuffer.read(cx).history.group_interval;
4056        multibuffer.update(cx, |multibuffer, cx| {
4057            multibuffer.push_excerpts(
4058                buffer_1.clone(),
4059                [ExcerptRange {
4060                    context: 0..buffer_1.read(cx).len(),
4061                    primary: None,
4062                }],
4063                cx,
4064            );
4065            multibuffer.push_excerpts(
4066                buffer_2.clone(),
4067                [ExcerptRange {
4068                    context: 0..buffer_2.read(cx).len(),
4069                    primary: None,
4070                }],
4071                cx,
4072            );
4073        });
4074
4075        let mut now = Instant::now();
4076
4077        multibuffer.update(cx, |multibuffer, cx| {
4078            multibuffer.start_transaction_at(now, cx);
4079            multibuffer.edit(
4080                [
4081                    (Point::new(0, 0)..Point::new(0, 0), "A"),
4082                    (Point::new(1, 0)..Point::new(1, 0), "A"),
4083                ],
4084                cx,
4085            );
4086            multibuffer.edit(
4087                [
4088                    (Point::new(0, 1)..Point::new(0, 1), "B"),
4089                    (Point::new(1, 1)..Point::new(1, 1), "B"),
4090                ],
4091                cx,
4092            );
4093            multibuffer.end_transaction_at(now, cx);
4094            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
4095
4096            // Edit buffer 1 through the multibuffer
4097            now += 2 * group_interval;
4098            multibuffer.start_transaction_at(now, cx);
4099            multibuffer.edit([(2..2, "C")], cx);
4100            multibuffer.end_transaction_at(now, cx);
4101            assert_eq!(multibuffer.read(cx).text(), "ABC1234\nAB5678");
4102
4103            // Edit buffer 1 independently
4104            buffer_1.update(cx, |buffer_1, cx| {
4105                buffer_1.start_transaction_at(now);
4106                buffer_1.edit([(3..3, "D")], cx);
4107                buffer_1.end_transaction_at(now, cx);
4108
4109                now += 2 * group_interval;
4110                buffer_1.start_transaction_at(now);
4111                buffer_1.edit([(4..4, "E")], cx);
4112                buffer_1.end_transaction_at(now, cx);
4113            });
4114            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
4115
4116            // An undo in the multibuffer undoes the multibuffer transaction
4117            // and also any individual buffer edits that have occured since
4118            // that transaction.
4119            multibuffer.undo(cx);
4120            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
4121
4122            multibuffer.undo(cx);
4123            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
4124
4125            multibuffer.redo(cx);
4126            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
4127
4128            multibuffer.redo(cx);
4129            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\nAB5678");
4130
4131            // Undo buffer 2 independently.
4132            buffer_2.update(cx, |buffer_2, cx| buffer_2.undo(cx));
4133            assert_eq!(multibuffer.read(cx).text(), "ABCDE1234\n5678");
4134
4135            // An undo in the multibuffer undoes the components of the
4136            // the last multibuffer transaction that are not already undone.
4137            multibuffer.undo(cx);
4138            assert_eq!(multibuffer.read(cx).text(), "AB1234\n5678");
4139
4140            multibuffer.undo(cx);
4141            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
4142
4143            multibuffer.redo(cx);
4144            assert_eq!(multibuffer.read(cx).text(), "AB1234\nAB5678");
4145
4146            buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
4147            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
4148
4149            // Redo stack gets cleared after an edit.
4150            now += 2 * group_interval;
4151            multibuffer.start_transaction_at(now, cx);
4152            multibuffer.edit([(0..0, "X")], cx);
4153            multibuffer.end_transaction_at(now, cx);
4154            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
4155            multibuffer.redo(cx);
4156            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
4157            multibuffer.undo(cx);
4158            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
4159            multibuffer.undo(cx);
4160            assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
4161        });
4162    }
4163}