text.rs

   1mod anchor;
   2pub mod locator;
   3#[cfg(any(test, feature = "test-support"))]
   4pub mod network;
   5pub mod operation_queue;
   6mod patch;
   7mod selection;
   8pub mod subscription;
   9#[cfg(test)]
  10mod tests;
  11mod undo_map;
  12
  13pub use anchor::*;
  14use anyhow::{anyhow, Result};
  15pub use clock::ReplicaId;
  16use collections::{HashMap, HashSet};
  17use locator::Locator;
  18use operation_queue::OperationQueue;
  19pub use patch::Patch;
  20use postage::{oneshot, prelude::*};
  21
  22use lazy_static::lazy_static;
  23use regex::Regex;
  24pub use rope::*;
  25pub use selection::*;
  26use std::{
  27    borrow::Cow,
  28    cmp::{self, Ordering, Reverse},
  29    future::Future,
  30    iter::Iterator,
  31    ops::{self, Deref, Range, Sub},
  32    str,
  33    sync::Arc,
  34    time::{Duration, Instant},
  35};
  36pub use subscription::*;
  37pub use sum_tree::Bias;
  38use sum_tree::{FilterCursor, SumTree, TreeMap};
  39use undo_map::UndoMap;
  40use util::ResultExt;
  41
  42#[cfg(any(test, feature = "test-support"))]
  43use util::RandomCharIter;
  44
  45lazy_static! {
  46    static ref LINE_SEPARATORS_REGEX: Regex = Regex::new("\r\n|\r|\u{2028}|\u{2029}").unwrap();
  47}
  48
  49pub type TransactionId = clock::Lamport;
  50
  51pub struct Buffer {
  52    snapshot: BufferSnapshot,
  53    history: History,
  54    deferred_ops: OperationQueue<Operation>,
  55    deferred_replicas: HashSet<ReplicaId>,
  56    pub lamport_clock: clock::Lamport,
  57    subscriptions: Topic,
  58    edit_id_resolvers: HashMap<clock::Lamport, Vec<oneshot::Sender<()>>>,
  59    wait_for_version_txs: Vec<(clock::Global, oneshot::Sender<()>)>,
  60}
  61
  62#[derive(Clone)]
  63pub struct BufferSnapshot {
  64    replica_id: ReplicaId,
  65    remote_id: u64,
  66    visible_text: Rope,
  67    deleted_text: Rope,
  68    line_ending: LineEnding,
  69    undo_map: UndoMap,
  70    fragments: SumTree<Fragment>,
  71    insertions: SumTree<InsertionFragment>,
  72    pub version: clock::Global,
  73}
  74
  75#[derive(Clone, Debug)]
  76pub struct HistoryEntry {
  77    transaction: Transaction,
  78    first_edit_at: Instant,
  79    last_edit_at: Instant,
  80    suppress_grouping: bool,
  81}
  82
  83#[derive(Clone, Debug)]
  84pub struct Transaction {
  85    pub id: TransactionId,
  86    pub edit_ids: Vec<clock::Lamport>,
  87    pub start: clock::Global,
  88}
  89
  90impl HistoryEntry {
  91    pub fn transaction_id(&self) -> TransactionId {
  92        self.transaction.id
  93    }
  94}
  95
  96struct History {
  97    base_text: Rope,
  98    operations: TreeMap<clock::Lamport, Operation>,
  99    insertion_slices: HashMap<clock::Lamport, Vec<InsertionSlice>>,
 100    undo_stack: Vec<HistoryEntry>,
 101    redo_stack: Vec<HistoryEntry>,
 102    transaction_depth: usize,
 103    group_interval: Duration,
 104}
 105
 106#[derive(Clone, Debug)]
 107struct InsertionSlice {
 108    insertion_id: clock::Lamport,
 109    range: Range<usize>,
 110}
 111
 112impl History {
 113    pub fn new(base_text: Rope) -> Self {
 114        Self {
 115            base_text,
 116            operations: Default::default(),
 117            insertion_slices: Default::default(),
 118            undo_stack: Vec::new(),
 119            redo_stack: Vec::new(),
 120            transaction_depth: 0,
 121            // Don't group transactions in tests unless we opt in, because it's a footgun.
 122            #[cfg(any(test, feature = "test-support"))]
 123            group_interval: Duration::ZERO,
 124            #[cfg(not(any(test, feature = "test-support")))]
 125            group_interval: Duration::from_millis(300),
 126        }
 127    }
 128
 129    fn push(&mut self, op: Operation) {
 130        self.operations.insert(op.timestamp(), op);
 131    }
 132
 133    fn start_transaction(
 134        &mut self,
 135        start: clock::Global,
 136        now: Instant,
 137        clock: &mut clock::Lamport,
 138    ) -> Option<TransactionId> {
 139        self.transaction_depth += 1;
 140        if self.transaction_depth == 1 {
 141            let id = clock.tick();
 142            self.undo_stack.push(HistoryEntry {
 143                transaction: Transaction {
 144                    id,
 145                    start,
 146                    edit_ids: Default::default(),
 147                },
 148                first_edit_at: now,
 149                last_edit_at: now,
 150                suppress_grouping: false,
 151            });
 152            Some(id)
 153        } else {
 154            None
 155        }
 156    }
 157
 158    fn end_transaction(&mut self, now: Instant) -> Option<&HistoryEntry> {
 159        assert_ne!(self.transaction_depth, 0);
 160        self.transaction_depth -= 1;
 161        if self.transaction_depth == 0 {
 162            if self
 163                .undo_stack
 164                .last()
 165                .unwrap()
 166                .transaction
 167                .edit_ids
 168                .is_empty()
 169            {
 170                self.undo_stack.pop();
 171                None
 172            } else {
 173                self.redo_stack.clear();
 174                let entry = self.undo_stack.last_mut().unwrap();
 175                entry.last_edit_at = now;
 176                Some(entry)
 177            }
 178        } else {
 179            None
 180        }
 181    }
 182
 183    fn group(&mut self) -> Option<TransactionId> {
 184        let mut count = 0;
 185        let mut entries = self.undo_stack.iter();
 186        if let Some(mut entry) = entries.next_back() {
 187            while let Some(prev_entry) = entries.next_back() {
 188                if !prev_entry.suppress_grouping
 189                    && entry.first_edit_at - prev_entry.last_edit_at <= self.group_interval
 190                {
 191                    entry = prev_entry;
 192                    count += 1;
 193                } else {
 194                    break;
 195                }
 196            }
 197        }
 198        self.group_trailing(count)
 199    }
 200
 201    fn group_until(&mut self, transaction_id: TransactionId) {
 202        let mut count = 0;
 203        for entry in self.undo_stack.iter().rev() {
 204            if entry.transaction_id() == transaction_id {
 205                self.group_trailing(count);
 206                break;
 207            } else if entry.suppress_grouping {
 208                break;
 209            } else {
 210                count += 1;
 211            }
 212        }
 213    }
 214
 215    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
 216        let new_len = self.undo_stack.len() - n;
 217        let (entries_to_keep, entries_to_merge) = self.undo_stack.split_at_mut(new_len);
 218        if let Some(last_entry) = entries_to_keep.last_mut() {
 219            for entry in &*entries_to_merge {
 220                for edit_id in &entry.transaction.edit_ids {
 221                    last_entry.transaction.edit_ids.push(*edit_id);
 222                }
 223            }
 224
 225            if let Some(entry) = entries_to_merge.last_mut() {
 226                last_entry.last_edit_at = entry.last_edit_at;
 227            }
 228        }
 229
 230        self.undo_stack.truncate(new_len);
 231        self.undo_stack.last().map(|e| e.transaction.id)
 232    }
 233
 234    fn finalize_last_transaction(&mut self) -> Option<&Transaction> {
 235        self.undo_stack.last_mut().map(|entry| {
 236            entry.suppress_grouping = true;
 237            &entry.transaction
 238        })
 239    }
 240
 241    fn push_transaction(&mut self, transaction: Transaction, now: Instant) {
 242        assert_eq!(self.transaction_depth, 0);
 243        self.undo_stack.push(HistoryEntry {
 244            transaction,
 245            first_edit_at: now,
 246            last_edit_at: now,
 247            suppress_grouping: false,
 248        });
 249        self.redo_stack.clear();
 250    }
 251
 252    fn push_undo(&mut self, op_id: clock::Lamport) {
 253        assert_ne!(self.transaction_depth, 0);
 254        if let Some(Operation::Edit(_)) = self.operations.get(&op_id) {
 255            let last_transaction = self.undo_stack.last_mut().unwrap();
 256            last_transaction.transaction.edit_ids.push(op_id);
 257        }
 258    }
 259
 260    fn pop_undo(&mut self) -> Option<&HistoryEntry> {
 261        assert_eq!(self.transaction_depth, 0);
 262        if let Some(entry) = self.undo_stack.pop() {
 263            self.redo_stack.push(entry);
 264            self.redo_stack.last()
 265        } else {
 266            None
 267        }
 268    }
 269
 270    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&HistoryEntry> {
 271        assert_eq!(self.transaction_depth, 0);
 272
 273        let entry_ix = self
 274            .undo_stack
 275            .iter()
 276            .rposition(|entry| entry.transaction.id == transaction_id)?;
 277        let entry = self.undo_stack.remove(entry_ix);
 278        self.redo_stack.push(entry);
 279        self.redo_stack.last()
 280    }
 281
 282    fn remove_from_undo_until(&mut self, transaction_id: TransactionId) -> &[HistoryEntry] {
 283        assert_eq!(self.transaction_depth, 0);
 284
 285        let redo_stack_start_len = self.redo_stack.len();
 286        if let Some(entry_ix) = self
 287            .undo_stack
 288            .iter()
 289            .rposition(|entry| entry.transaction.id == transaction_id)
 290        {
 291            self.redo_stack
 292                .extend(self.undo_stack.drain(entry_ix..).rev());
 293        }
 294        &self.redo_stack[redo_stack_start_len..]
 295    }
 296
 297    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
 298        assert_eq!(self.transaction_depth, 0);
 299        if let Some(entry_ix) = self
 300            .undo_stack
 301            .iter()
 302            .rposition(|entry| entry.transaction.id == transaction_id)
 303        {
 304            Some(self.undo_stack.remove(entry_ix).transaction)
 305        } else if let Some(entry_ix) = self
 306            .redo_stack
 307            .iter()
 308            .rposition(|entry| entry.transaction.id == transaction_id)
 309        {
 310            Some(self.redo_stack.remove(entry_ix).transaction)
 311        } else {
 312            None
 313        }
 314    }
 315
 316    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
 317        let entry = self
 318            .undo_stack
 319            .iter_mut()
 320            .rfind(|entry| entry.transaction.id == transaction_id)
 321            .or_else(|| {
 322                self.redo_stack
 323                    .iter_mut()
 324                    .rfind(|entry| entry.transaction.id == transaction_id)
 325            })?;
 326        Some(&mut entry.transaction)
 327    }
 328
 329    fn merge_transactions(&mut self, transaction: TransactionId, destination: TransactionId) {
 330        if let Some(transaction) = self.forget(transaction) {
 331            if let Some(destination) = self.transaction_mut(destination) {
 332                destination.edit_ids.extend(transaction.edit_ids);
 333            }
 334        }
 335    }
 336
 337    fn pop_redo(&mut self) -> Option<&HistoryEntry> {
 338        assert_eq!(self.transaction_depth, 0);
 339        if let Some(entry) = self.redo_stack.pop() {
 340            self.undo_stack.push(entry);
 341            self.undo_stack.last()
 342        } else {
 343            None
 344        }
 345    }
 346
 347    fn remove_from_redo(&mut self, transaction_id: TransactionId) -> &[HistoryEntry] {
 348        assert_eq!(self.transaction_depth, 0);
 349
 350        let undo_stack_start_len = self.undo_stack.len();
 351        if let Some(entry_ix) = self
 352            .redo_stack
 353            .iter()
 354            .rposition(|entry| entry.transaction.id == transaction_id)
 355        {
 356            self.undo_stack
 357                .extend(self.redo_stack.drain(entry_ix..).rev());
 358        }
 359        &self.undo_stack[undo_stack_start_len..]
 360    }
 361}
 362
 363struct Edits<'a, D: TextDimension, F: FnMut(&FragmentSummary) -> bool> {
 364    visible_cursor: rope::Cursor<'a>,
 365    deleted_cursor: rope::Cursor<'a>,
 366    fragments_cursor: Option<FilterCursor<'a, F, Fragment, FragmentTextSummary>>,
 367    undos: &'a UndoMap,
 368    since: &'a clock::Global,
 369    old_end: D,
 370    new_end: D,
 371    range: Range<(&'a Locator, usize)>,
 372    buffer_id: u64,
 373}
 374
 375#[derive(Clone, Debug, Default, Eq, PartialEq)]
 376pub struct Edit<D> {
 377    pub old: Range<D>,
 378    pub new: Range<D>,
 379}
 380
 381impl<D> Edit<D>
 382where
 383    D: Sub<D, Output = D> + PartialEq + Copy,
 384{
 385    pub fn old_len(&self) -> D {
 386        self.old.end - self.old.start
 387    }
 388
 389    pub fn new_len(&self) -> D {
 390        self.new.end - self.new.start
 391    }
 392
 393    pub fn is_empty(&self) -> bool {
 394        self.old.start == self.old.end && self.new.start == self.new.end
 395    }
 396}
 397
 398impl<D1, D2> Edit<(D1, D2)> {
 399    pub fn flatten(self) -> (Edit<D1>, Edit<D2>) {
 400        (
 401            Edit {
 402                old: self.old.start.0..self.old.end.0,
 403                new: self.new.start.0..self.new.end.0,
 404            },
 405            Edit {
 406                old: self.old.start.1..self.old.end.1,
 407                new: self.new.start.1..self.new.end.1,
 408            },
 409        )
 410    }
 411}
 412
 413#[derive(Eq, PartialEq, Clone, Debug)]
 414pub struct Fragment {
 415    pub id: Locator,
 416    pub timestamp: clock::Lamport,
 417    pub insertion_offset: usize,
 418    pub len: usize,
 419    pub visible: bool,
 420    pub deletions: HashSet<clock::Lamport>,
 421    pub max_undos: clock::Global,
 422}
 423
 424#[derive(Eq, PartialEq, Clone, Debug)]
 425pub struct FragmentSummary {
 426    text: FragmentTextSummary,
 427    max_id: Locator,
 428    max_version: clock::Global,
 429    min_insertion_version: clock::Global,
 430    max_insertion_version: clock::Global,
 431}
 432
 433#[derive(Copy, Default, Clone, Debug, PartialEq, Eq)]
 434struct FragmentTextSummary {
 435    visible: usize,
 436    deleted: usize,
 437}
 438
 439impl<'a> sum_tree::Dimension<'a, FragmentSummary> for FragmentTextSummary {
 440    fn add_summary(&mut self, summary: &'a FragmentSummary, _: &Option<clock::Global>) {
 441        self.visible += summary.text.visible;
 442        self.deleted += summary.text.deleted;
 443    }
 444}
 445
 446#[derive(Eq, PartialEq, Clone, Debug)]
 447struct InsertionFragment {
 448    timestamp: clock::Lamport,
 449    split_offset: usize,
 450    fragment_id: Locator,
 451}
 452
 453#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
 454struct InsertionFragmentKey {
 455    timestamp: clock::Lamport,
 456    split_offset: usize,
 457}
 458
 459#[derive(Clone, Debug, Eq, PartialEq)]
 460pub enum Operation {
 461    Edit(EditOperation),
 462    Undo(UndoOperation),
 463}
 464
 465#[derive(Clone, Debug, Eq, PartialEq)]
 466pub struct EditOperation {
 467    pub timestamp: clock::Lamport,
 468    pub version: clock::Global,
 469    pub ranges: Vec<Range<FullOffset>>,
 470    pub new_text: Vec<Arc<str>>,
 471}
 472
 473#[derive(Clone, Debug, Eq, PartialEq)]
 474pub struct UndoOperation {
 475    pub timestamp: clock::Lamport,
 476    pub version: clock::Global,
 477    pub counts: HashMap<clock::Lamport, u32>,
 478}
 479
 480impl Buffer {
 481    pub fn new(replica_id: u16, remote_id: u64, mut base_text: String) -> Buffer {
 482        let line_ending = LineEnding::detect(&base_text);
 483        LineEnding::normalize(&mut base_text);
 484
 485        let history = History::new(Rope::from(base_text.as_ref()));
 486        let mut fragments = SumTree::new();
 487        let mut insertions = SumTree::new();
 488
 489        let mut lamport_clock = clock::Lamport::new(replica_id);
 490        let mut version = clock::Global::new();
 491
 492        let visible_text = history.base_text.clone();
 493        if !visible_text.is_empty() {
 494            let insertion_timestamp = clock::Lamport {
 495                replica_id: 0,
 496                value: 1,
 497            };
 498            lamport_clock.observe(insertion_timestamp);
 499            version.observe(insertion_timestamp);
 500            let fragment_id = Locator::between(&Locator::min(), &Locator::max());
 501            let fragment = Fragment {
 502                id: fragment_id,
 503                timestamp: insertion_timestamp,
 504                insertion_offset: 0,
 505                len: visible_text.len(),
 506                visible: true,
 507                deletions: Default::default(),
 508                max_undos: Default::default(),
 509            };
 510            insertions.push(InsertionFragment::new(&fragment), &());
 511            fragments.push(fragment, &None);
 512        }
 513
 514        Buffer {
 515            snapshot: BufferSnapshot {
 516                replica_id,
 517                remote_id,
 518                visible_text,
 519                deleted_text: Rope::new(),
 520                line_ending,
 521                fragments,
 522                insertions,
 523                version,
 524                undo_map: Default::default(),
 525            },
 526            history,
 527            deferred_ops: OperationQueue::new(),
 528            deferred_replicas: HashSet::default(),
 529            lamport_clock,
 530            subscriptions: Default::default(),
 531            edit_id_resolvers: Default::default(),
 532            wait_for_version_txs: Default::default(),
 533        }
 534    }
 535
 536    pub fn version(&self) -> clock::Global {
 537        self.version.clone()
 538    }
 539
 540    pub fn snapshot(&self) -> BufferSnapshot {
 541        self.snapshot.clone()
 542    }
 543
 544    pub fn replica_id(&self) -> ReplicaId {
 545        self.lamport_clock.replica_id
 546    }
 547
 548    pub fn remote_id(&self) -> u64 {
 549        self.remote_id
 550    }
 551
 552    pub fn deferred_ops_len(&self) -> usize {
 553        self.deferred_ops.len()
 554    }
 555
 556    pub fn transaction_group_interval(&self) -> Duration {
 557        self.history.group_interval
 558    }
 559
 560    pub fn edit<R, I, S, T>(&mut self, edits: R) -> Operation
 561    where
 562        R: IntoIterator<IntoIter = I>,
 563        I: ExactSizeIterator<Item = (Range<S>, T)>,
 564        S: ToOffset,
 565        T: Into<Arc<str>>,
 566    {
 567        let edits = edits
 568            .into_iter()
 569            .map(|(range, new_text)| (range, new_text.into()));
 570
 571        self.start_transaction();
 572        let timestamp = self.lamport_clock.tick();
 573        let operation = Operation::Edit(self.apply_local_edit(edits, timestamp));
 574
 575        self.history.push(operation.clone());
 576        self.history.push_undo(operation.timestamp());
 577        self.snapshot.version.observe(operation.timestamp());
 578        self.end_transaction();
 579        operation
 580    }
 581
 582    fn apply_local_edit<S: ToOffset, T: Into<Arc<str>>>(
 583        &mut self,
 584        edits: impl ExactSizeIterator<Item = (Range<S>, T)>,
 585        timestamp: clock::Lamport,
 586    ) -> EditOperation {
 587        let mut edits_patch = Patch::default();
 588        let mut edit_op = EditOperation {
 589            timestamp,
 590            version: self.version(),
 591            ranges: Vec::with_capacity(edits.len()),
 592            new_text: Vec::with_capacity(edits.len()),
 593        };
 594        let mut new_insertions = Vec::new();
 595        let mut insertion_offset = 0;
 596        let mut insertion_slices = Vec::new();
 597
 598        let mut edits = edits
 599            .map(|(range, new_text)| (range.to_offset(&*self), new_text))
 600            .peekable();
 601
 602        let mut new_ropes =
 603            RopeBuilder::new(self.visible_text.cursor(0), self.deleted_text.cursor(0));
 604        let mut old_fragments = self.fragments.cursor::<FragmentTextSummary>();
 605        let mut new_fragments =
 606            old_fragments.slice(&edits.peek().unwrap().0.start, Bias::Right, &None);
 607        new_ropes.append(new_fragments.summary().text);
 608
 609        let mut fragment_start = old_fragments.start().visible;
 610        for (range, new_text) in edits {
 611            let new_text = LineEnding::normalize_arc(new_text.into());
 612            let fragment_end = old_fragments.end(&None).visible;
 613
 614            // If the current fragment ends before this range, then jump ahead to the first fragment
 615            // that extends past the start of this range, reusing any intervening fragments.
 616            if fragment_end < range.start {
 617                // If the current fragment has been partially consumed, then consume the rest of it
 618                // and advance to the next fragment before slicing.
 619                if fragment_start > old_fragments.start().visible {
 620                    if fragment_end > fragment_start {
 621                        let mut suffix = old_fragments.item().unwrap().clone();
 622                        suffix.len = fragment_end - fragment_start;
 623                        suffix.insertion_offset += fragment_start - old_fragments.start().visible;
 624                        new_insertions.push(InsertionFragment::insert_new(&suffix));
 625                        new_ropes.push_fragment(&suffix, suffix.visible);
 626                        new_fragments.push(suffix, &None);
 627                    }
 628                    old_fragments.next(&None);
 629                }
 630
 631                let slice = old_fragments.slice(&range.start, Bias::Right, &None);
 632                new_ropes.append(slice.summary().text);
 633                new_fragments.append(slice, &None);
 634                fragment_start = old_fragments.start().visible;
 635            }
 636
 637            let full_range_start = FullOffset(range.start + old_fragments.start().deleted);
 638
 639            // Preserve any portion of the current fragment that precedes this range.
 640            if fragment_start < range.start {
 641                let mut prefix = old_fragments.item().unwrap().clone();
 642                prefix.len = range.start - fragment_start;
 643                prefix.insertion_offset += fragment_start - old_fragments.start().visible;
 644                prefix.id = Locator::between(&new_fragments.summary().max_id, &prefix.id);
 645                new_insertions.push(InsertionFragment::insert_new(&prefix));
 646                new_ropes.push_fragment(&prefix, prefix.visible);
 647                new_fragments.push(prefix, &None);
 648                fragment_start = range.start;
 649            }
 650
 651            // Insert the new text before any existing fragments within the range.
 652            if !new_text.is_empty() {
 653                let new_start = new_fragments.summary().text.visible;
 654
 655                let fragment = Fragment {
 656                    id: Locator::between(
 657                        &new_fragments.summary().max_id,
 658                        old_fragments
 659                            .item()
 660                            .map_or(&Locator::max(), |old_fragment| &old_fragment.id),
 661                    ),
 662                    timestamp,
 663                    insertion_offset,
 664                    len: new_text.len(),
 665                    deletions: Default::default(),
 666                    max_undos: Default::default(),
 667                    visible: true,
 668                };
 669                edits_patch.push(Edit {
 670                    old: fragment_start..fragment_start,
 671                    new: new_start..new_start + new_text.len(),
 672                });
 673                insertion_slices.push(fragment.insertion_slice());
 674                new_insertions.push(InsertionFragment::insert_new(&fragment));
 675                new_ropes.push_str(new_text.as_ref());
 676                new_fragments.push(fragment, &None);
 677                insertion_offset += new_text.len();
 678            }
 679
 680            // Advance through every fragment that intersects this range, marking the intersecting
 681            // portions as deleted.
 682            while fragment_start < range.end {
 683                let fragment = old_fragments.item().unwrap();
 684                let fragment_end = old_fragments.end(&None).visible;
 685                let mut intersection = fragment.clone();
 686                let intersection_end = cmp::min(range.end, fragment_end);
 687                if fragment.visible {
 688                    intersection.len = intersection_end - fragment_start;
 689                    intersection.insertion_offset += fragment_start - old_fragments.start().visible;
 690                    intersection.id =
 691                        Locator::between(&new_fragments.summary().max_id, &intersection.id);
 692                    intersection.deletions.insert(timestamp);
 693                    intersection.visible = false;
 694                }
 695                if intersection.len > 0 {
 696                    if fragment.visible && !intersection.visible {
 697                        let new_start = new_fragments.summary().text.visible;
 698                        edits_patch.push(Edit {
 699                            old: fragment_start..intersection_end,
 700                            new: new_start..new_start,
 701                        });
 702                        insertion_slices.push(intersection.insertion_slice());
 703                    }
 704                    new_insertions.push(InsertionFragment::insert_new(&intersection));
 705                    new_ropes.push_fragment(&intersection, fragment.visible);
 706                    new_fragments.push(intersection, &None);
 707                    fragment_start = intersection_end;
 708                }
 709                if fragment_end <= range.end {
 710                    old_fragments.next(&None);
 711                }
 712            }
 713
 714            let full_range_end = FullOffset(range.end + old_fragments.start().deleted);
 715            edit_op.ranges.push(full_range_start..full_range_end);
 716            edit_op.new_text.push(new_text);
 717        }
 718
 719        // If the current fragment has been partially consumed, then consume the rest of it
 720        // and advance to the next fragment before slicing.
 721        if fragment_start > old_fragments.start().visible {
 722            let fragment_end = old_fragments.end(&None).visible;
 723            if fragment_end > fragment_start {
 724                let mut suffix = old_fragments.item().unwrap().clone();
 725                suffix.len = fragment_end - fragment_start;
 726                suffix.insertion_offset += fragment_start - old_fragments.start().visible;
 727                new_insertions.push(InsertionFragment::insert_new(&suffix));
 728                new_ropes.push_fragment(&suffix, suffix.visible);
 729                new_fragments.push(suffix, &None);
 730            }
 731            old_fragments.next(&None);
 732        }
 733
 734        let suffix = old_fragments.suffix(&None);
 735        new_ropes.append(suffix.summary().text);
 736        new_fragments.append(suffix, &None);
 737        let (visible_text, deleted_text) = new_ropes.finish();
 738        drop(old_fragments);
 739
 740        self.snapshot.fragments = new_fragments;
 741        self.snapshot.insertions.edit(new_insertions, &());
 742        self.snapshot.visible_text = visible_text;
 743        self.snapshot.deleted_text = deleted_text;
 744        self.subscriptions.publish_mut(&edits_patch);
 745        self.history
 746            .insertion_slices
 747            .insert(timestamp, insertion_slices);
 748        edit_op
 749    }
 750
 751    pub fn set_line_ending(&mut self, line_ending: LineEnding) {
 752        self.snapshot.line_ending = line_ending;
 753    }
 754
 755    pub fn apply_ops<I: IntoIterator<Item = Operation>>(&mut self, ops: I) -> Result<()> {
 756        let mut deferred_ops = Vec::new();
 757        for op in ops {
 758            self.history.push(op.clone());
 759            if self.can_apply_op(&op) {
 760                self.apply_op(op)?;
 761            } else {
 762                self.deferred_replicas.insert(op.replica_id());
 763                deferred_ops.push(op);
 764            }
 765        }
 766        self.deferred_ops.insert(deferred_ops);
 767        self.flush_deferred_ops()?;
 768        Ok(())
 769    }
 770
 771    fn apply_op(&mut self, op: Operation) -> Result<()> {
 772        match op {
 773            Operation::Edit(edit) => {
 774                if !self.version.observed(edit.timestamp) {
 775                    self.apply_remote_edit(
 776                        &edit.version,
 777                        &edit.ranges,
 778                        &edit.new_text,
 779                        edit.timestamp,
 780                    );
 781                    self.snapshot.version.observe(edit.timestamp);
 782                    self.lamport_clock.observe(edit.timestamp);
 783                    self.resolve_edit(edit.timestamp);
 784                }
 785            }
 786            Operation::Undo(undo) => {
 787                if !self.version.observed(undo.timestamp) {
 788                    self.apply_undo(&undo)?;
 789                    self.snapshot.version.observe(undo.timestamp);
 790                    self.lamport_clock.observe(undo.timestamp);
 791                }
 792            }
 793        }
 794        self.wait_for_version_txs.retain_mut(|(version, tx)| {
 795            if self.snapshot.version().observed_all(version) {
 796                tx.try_send(()).ok();
 797                false
 798            } else {
 799                true
 800            }
 801        });
 802        Ok(())
 803    }
 804
 805    fn apply_remote_edit(
 806        &mut self,
 807        version: &clock::Global,
 808        ranges: &[Range<FullOffset>],
 809        new_text: &[Arc<str>],
 810        timestamp: clock::Lamport,
 811    ) {
 812        if ranges.is_empty() {
 813            return;
 814        }
 815
 816        let edits = ranges.iter().zip(new_text.iter());
 817        let mut edits_patch = Patch::default();
 818        let mut insertion_slices = Vec::new();
 819        let cx = Some(version.clone());
 820        let mut new_insertions = Vec::new();
 821        let mut insertion_offset = 0;
 822        let mut new_ropes =
 823            RopeBuilder::new(self.visible_text.cursor(0), self.deleted_text.cursor(0));
 824        let mut old_fragments = self.fragments.cursor::<(VersionedFullOffset, usize)>();
 825        let mut new_fragments = old_fragments.slice(
 826            &VersionedFullOffset::Offset(ranges[0].start),
 827            Bias::Left,
 828            &cx,
 829        );
 830        new_ropes.append(new_fragments.summary().text);
 831
 832        let mut fragment_start = old_fragments.start().0.full_offset();
 833        for (range, new_text) in edits {
 834            let fragment_end = old_fragments.end(&cx).0.full_offset();
 835
 836            // If the current fragment ends before this range, then jump ahead to the first fragment
 837            // that extends past the start of this range, reusing any intervening fragments.
 838            if fragment_end < range.start {
 839                // If the current fragment has been partially consumed, then consume the rest of it
 840                // and advance to the next fragment before slicing.
 841                if fragment_start > old_fragments.start().0.full_offset() {
 842                    if fragment_end > fragment_start {
 843                        let mut suffix = old_fragments.item().unwrap().clone();
 844                        suffix.len = fragment_end.0 - fragment_start.0;
 845                        suffix.insertion_offset +=
 846                            fragment_start - old_fragments.start().0.full_offset();
 847                        new_insertions.push(InsertionFragment::insert_new(&suffix));
 848                        new_ropes.push_fragment(&suffix, suffix.visible);
 849                        new_fragments.push(suffix, &None);
 850                    }
 851                    old_fragments.next(&cx);
 852                }
 853
 854                let slice =
 855                    old_fragments.slice(&VersionedFullOffset::Offset(range.start), Bias::Left, &cx);
 856                new_ropes.append(slice.summary().text);
 857                new_fragments.append(slice, &None);
 858                fragment_start = old_fragments.start().0.full_offset();
 859            }
 860
 861            // If we are at the end of a non-concurrent fragment, advance to the next one.
 862            let fragment_end = old_fragments.end(&cx).0.full_offset();
 863            if fragment_end == range.start && fragment_end > fragment_start {
 864                let mut fragment = old_fragments.item().unwrap().clone();
 865                fragment.len = fragment_end.0 - fragment_start.0;
 866                fragment.insertion_offset += fragment_start - old_fragments.start().0.full_offset();
 867                new_insertions.push(InsertionFragment::insert_new(&fragment));
 868                new_ropes.push_fragment(&fragment, fragment.visible);
 869                new_fragments.push(fragment, &None);
 870                old_fragments.next(&cx);
 871                fragment_start = old_fragments.start().0.full_offset();
 872            }
 873
 874            // Skip over insertions that are concurrent to this edit, but have a lower lamport
 875            // timestamp.
 876            while let Some(fragment) = old_fragments.item() {
 877                if fragment_start == range.start && fragment.timestamp > timestamp {
 878                    new_ropes.push_fragment(fragment, fragment.visible);
 879                    new_fragments.push(fragment.clone(), &None);
 880                    old_fragments.next(&cx);
 881                    debug_assert_eq!(fragment_start, range.start);
 882                } else {
 883                    break;
 884                }
 885            }
 886            debug_assert!(fragment_start <= range.start);
 887
 888            // Preserve any portion of the current fragment that precedes this range.
 889            if fragment_start < range.start {
 890                let mut prefix = old_fragments.item().unwrap().clone();
 891                prefix.len = range.start.0 - fragment_start.0;
 892                prefix.insertion_offset += fragment_start - old_fragments.start().0.full_offset();
 893                prefix.id = Locator::between(&new_fragments.summary().max_id, &prefix.id);
 894                new_insertions.push(InsertionFragment::insert_new(&prefix));
 895                fragment_start = range.start;
 896                new_ropes.push_fragment(&prefix, prefix.visible);
 897                new_fragments.push(prefix, &None);
 898            }
 899
 900            // Insert the new text before any existing fragments within the range.
 901            if !new_text.is_empty() {
 902                let mut old_start = old_fragments.start().1;
 903                if old_fragments.item().map_or(false, |f| f.visible) {
 904                    old_start += fragment_start.0 - old_fragments.start().0.full_offset().0;
 905                }
 906                let new_start = new_fragments.summary().text.visible;
 907                let fragment = Fragment {
 908                    id: Locator::between(
 909                        &new_fragments.summary().max_id,
 910                        old_fragments
 911                            .item()
 912                            .map_or(&Locator::max(), |old_fragment| &old_fragment.id),
 913                    ),
 914                    timestamp,
 915                    insertion_offset,
 916                    len: new_text.len(),
 917                    deletions: Default::default(),
 918                    max_undos: Default::default(),
 919                    visible: true,
 920                };
 921                edits_patch.push(Edit {
 922                    old: old_start..old_start,
 923                    new: new_start..new_start + new_text.len(),
 924                });
 925                insertion_slices.push(fragment.insertion_slice());
 926                new_insertions.push(InsertionFragment::insert_new(&fragment));
 927                new_ropes.push_str(new_text);
 928                new_fragments.push(fragment, &None);
 929                insertion_offset += new_text.len();
 930            }
 931
 932            // Advance through every fragment that intersects this range, marking the intersecting
 933            // portions as deleted.
 934            while fragment_start < range.end {
 935                let fragment = old_fragments.item().unwrap();
 936                let fragment_end = old_fragments.end(&cx).0.full_offset();
 937                let mut intersection = fragment.clone();
 938                let intersection_end = cmp::min(range.end, fragment_end);
 939                if fragment.was_visible(version, &self.undo_map) {
 940                    intersection.len = intersection_end.0 - fragment_start.0;
 941                    intersection.insertion_offset +=
 942                        fragment_start - old_fragments.start().0.full_offset();
 943                    intersection.id =
 944                        Locator::between(&new_fragments.summary().max_id, &intersection.id);
 945                    intersection.deletions.insert(timestamp);
 946                    intersection.visible = false;
 947                    insertion_slices.push(intersection.insertion_slice());
 948                }
 949                if intersection.len > 0 {
 950                    if fragment.visible && !intersection.visible {
 951                        let old_start = old_fragments.start().1
 952                            + (fragment_start.0 - old_fragments.start().0.full_offset().0);
 953                        let new_start = new_fragments.summary().text.visible;
 954                        edits_patch.push(Edit {
 955                            old: old_start..old_start + intersection.len,
 956                            new: new_start..new_start,
 957                        });
 958                    }
 959                    new_insertions.push(InsertionFragment::insert_new(&intersection));
 960                    new_ropes.push_fragment(&intersection, fragment.visible);
 961                    new_fragments.push(intersection, &None);
 962                    fragment_start = intersection_end;
 963                }
 964                if fragment_end <= range.end {
 965                    old_fragments.next(&cx);
 966                }
 967            }
 968        }
 969
 970        // If the current fragment has been partially consumed, then consume the rest of it
 971        // and advance to the next fragment before slicing.
 972        if fragment_start > old_fragments.start().0.full_offset() {
 973            let fragment_end = old_fragments.end(&cx).0.full_offset();
 974            if fragment_end > fragment_start {
 975                let mut suffix = old_fragments.item().unwrap().clone();
 976                suffix.len = fragment_end.0 - fragment_start.0;
 977                suffix.insertion_offset += fragment_start - old_fragments.start().0.full_offset();
 978                new_insertions.push(InsertionFragment::insert_new(&suffix));
 979                new_ropes.push_fragment(&suffix, suffix.visible);
 980                new_fragments.push(suffix, &None);
 981            }
 982            old_fragments.next(&cx);
 983        }
 984
 985        let suffix = old_fragments.suffix(&cx);
 986        new_ropes.append(suffix.summary().text);
 987        new_fragments.append(suffix, &None);
 988        let (visible_text, deleted_text) = new_ropes.finish();
 989        drop(old_fragments);
 990
 991        self.snapshot.fragments = new_fragments;
 992        self.snapshot.visible_text = visible_text;
 993        self.snapshot.deleted_text = deleted_text;
 994        self.snapshot.insertions.edit(new_insertions, &());
 995        self.history
 996            .insertion_slices
 997            .insert(timestamp, insertion_slices);
 998        self.subscriptions.publish_mut(&edits_patch)
 999    }
1000
1001    fn fragment_ids_for_edits<'a>(
1002        &'a self,
1003        edit_ids: impl Iterator<Item = &'a clock::Lamport>,
1004    ) -> Vec<&'a Locator> {
1005        // Get all of the insertion slices changed by the given edits.
1006        let mut insertion_slices = Vec::new();
1007        for edit_id in edit_ids {
1008            if let Some(slices) = self.history.insertion_slices.get(edit_id) {
1009                insertion_slices.extend_from_slice(slices)
1010            }
1011        }
1012        insertion_slices
1013            .sort_unstable_by_key(|s| (s.insertion_id, s.range.start, Reverse(s.range.end)));
1014
1015        // Get all of the fragments corresponding to these insertion slices.
1016        let mut fragment_ids = Vec::new();
1017        let mut insertions_cursor = self.insertions.cursor::<InsertionFragmentKey>();
1018        for insertion_slice in &insertion_slices {
1019            if insertion_slice.insertion_id != insertions_cursor.start().timestamp
1020                || insertion_slice.range.start > insertions_cursor.start().split_offset
1021            {
1022                insertions_cursor.seek_forward(
1023                    &InsertionFragmentKey {
1024                        timestamp: insertion_slice.insertion_id,
1025                        split_offset: insertion_slice.range.start,
1026                    },
1027                    Bias::Left,
1028                    &(),
1029                );
1030            }
1031            while let Some(item) = insertions_cursor.item() {
1032                if item.timestamp != insertion_slice.insertion_id
1033                    || item.split_offset >= insertion_slice.range.end
1034                {
1035                    break;
1036                }
1037                fragment_ids.push(&item.fragment_id);
1038                insertions_cursor.next(&());
1039            }
1040        }
1041        fragment_ids.sort_unstable();
1042        fragment_ids
1043    }
1044
1045    fn apply_undo(&mut self, undo: &UndoOperation) -> Result<()> {
1046        self.snapshot.undo_map.insert(undo);
1047
1048        let mut edits = Patch::default();
1049        let mut old_fragments = self.fragments.cursor::<(Option<&Locator>, usize)>();
1050        let mut new_fragments = SumTree::new();
1051        let mut new_ropes =
1052            RopeBuilder::new(self.visible_text.cursor(0), self.deleted_text.cursor(0));
1053
1054        for fragment_id in self.fragment_ids_for_edits(undo.counts.keys()) {
1055            let preceding_fragments = old_fragments.slice(&Some(fragment_id), Bias::Left, &None);
1056            new_ropes.append(preceding_fragments.summary().text);
1057            new_fragments.append(preceding_fragments, &None);
1058
1059            if let Some(fragment) = old_fragments.item() {
1060                let mut fragment = fragment.clone();
1061                let fragment_was_visible = fragment.visible;
1062
1063                fragment.visible = fragment.is_visible(&self.undo_map);
1064                fragment.max_undos.observe(undo.timestamp);
1065
1066                let old_start = old_fragments.start().1;
1067                let new_start = new_fragments.summary().text.visible;
1068                if fragment_was_visible && !fragment.visible {
1069                    edits.push(Edit {
1070                        old: old_start..old_start + fragment.len,
1071                        new: new_start..new_start,
1072                    });
1073                } else if !fragment_was_visible && fragment.visible {
1074                    edits.push(Edit {
1075                        old: old_start..old_start,
1076                        new: new_start..new_start + fragment.len,
1077                    });
1078                }
1079                new_ropes.push_fragment(&fragment, fragment_was_visible);
1080                new_fragments.push(fragment, &None);
1081
1082                old_fragments.next(&None);
1083            }
1084        }
1085
1086        let suffix = old_fragments.suffix(&None);
1087        new_ropes.append(suffix.summary().text);
1088        new_fragments.append(suffix, &None);
1089
1090        drop(old_fragments);
1091        let (visible_text, deleted_text) = new_ropes.finish();
1092        self.snapshot.fragments = new_fragments;
1093        self.snapshot.visible_text = visible_text;
1094        self.snapshot.deleted_text = deleted_text;
1095        self.subscriptions.publish_mut(&edits);
1096        Ok(())
1097    }
1098
1099    fn flush_deferred_ops(&mut self) -> Result<()> {
1100        self.deferred_replicas.clear();
1101        let mut deferred_ops = Vec::new();
1102        for op in self.deferred_ops.drain().iter().cloned() {
1103            if self.can_apply_op(&op) {
1104                self.apply_op(op)?;
1105            } else {
1106                self.deferred_replicas.insert(op.replica_id());
1107                deferred_ops.push(op);
1108            }
1109        }
1110        self.deferred_ops.insert(deferred_ops);
1111        Ok(())
1112    }
1113
1114    fn can_apply_op(&self, op: &Operation) -> bool {
1115        if self.deferred_replicas.contains(&op.replica_id()) {
1116            false
1117        } else {
1118            self.version.observed_all(match op {
1119                Operation::Edit(edit) => &edit.version,
1120                Operation::Undo(undo) => &undo.version,
1121            })
1122        }
1123    }
1124
1125    pub fn peek_undo_stack(&self) -> Option<&HistoryEntry> {
1126        self.history.undo_stack.last()
1127    }
1128
1129    pub fn peek_redo_stack(&self) -> Option<&HistoryEntry> {
1130        self.history.redo_stack.last()
1131    }
1132
1133    pub fn start_transaction(&mut self) -> Option<TransactionId> {
1134        self.start_transaction_at(Instant::now())
1135    }
1136
1137    pub fn start_transaction_at(&mut self, now: Instant) -> Option<TransactionId> {
1138        self.history
1139            .start_transaction(self.version.clone(), now, &mut self.lamport_clock)
1140    }
1141
1142    pub fn end_transaction(&mut self) -> Option<(TransactionId, clock::Global)> {
1143        self.end_transaction_at(Instant::now())
1144    }
1145
1146    pub fn end_transaction_at(&mut self, now: Instant) -> Option<(TransactionId, clock::Global)> {
1147        if let Some(entry) = self.history.end_transaction(now) {
1148            let since = entry.transaction.start.clone();
1149            let id = self.history.group().unwrap();
1150            Some((id, since))
1151        } else {
1152            None
1153        }
1154    }
1155
1156    pub fn finalize_last_transaction(&mut self) -> Option<&Transaction> {
1157        self.history.finalize_last_transaction()
1158    }
1159
1160    pub fn group_until_transaction(&mut self, transaction_id: TransactionId) {
1161        self.history.group_until(transaction_id);
1162    }
1163
1164    pub fn base_text(&self) -> &Rope {
1165        &self.history.base_text
1166    }
1167
1168    pub fn operations(&self) -> &TreeMap<clock::Lamport, Operation> {
1169        &self.history.operations
1170    }
1171
1172    pub fn undo(&mut self) -> Option<(TransactionId, Operation)> {
1173        if let Some(entry) = self.history.pop_undo() {
1174            let transaction = entry.transaction.clone();
1175            let transaction_id = transaction.id;
1176            let op = self.undo_or_redo(transaction).unwrap();
1177            Some((transaction_id, op))
1178        } else {
1179            None
1180        }
1181    }
1182
1183    pub fn undo_transaction(&mut self, transaction_id: TransactionId) -> Option<Operation> {
1184        let transaction = self
1185            .history
1186            .remove_from_undo(transaction_id)?
1187            .transaction
1188            .clone();
1189        self.undo_or_redo(transaction).log_err()
1190    }
1191
1192    #[allow(clippy::needless_collect)]
1193    pub fn undo_to_transaction(&mut self, transaction_id: TransactionId) -> Vec<Operation> {
1194        let transactions = self
1195            .history
1196            .remove_from_undo_until(transaction_id)
1197            .iter()
1198            .map(|entry| entry.transaction.clone())
1199            .collect::<Vec<_>>();
1200
1201        transactions
1202            .into_iter()
1203            .map(|transaction| self.undo_or_redo(transaction).unwrap())
1204            .collect()
1205    }
1206
1207    pub fn forget_transaction(&mut self, transaction_id: TransactionId) {
1208        self.history.forget(transaction_id);
1209    }
1210
1211    pub fn merge_transactions(&mut self, transaction: TransactionId, destination: TransactionId) {
1212        self.history.merge_transactions(transaction, destination);
1213    }
1214
1215    pub fn redo(&mut self) -> Option<(TransactionId, Operation)> {
1216        if let Some(entry) = self.history.pop_redo() {
1217            let transaction = entry.transaction.clone();
1218            let transaction_id = transaction.id;
1219            let op = self.undo_or_redo(transaction).unwrap();
1220            Some((transaction_id, op))
1221        } else {
1222            None
1223        }
1224    }
1225
1226    #[allow(clippy::needless_collect)]
1227    pub fn redo_to_transaction(&mut self, transaction_id: TransactionId) -> Vec<Operation> {
1228        let transactions = self
1229            .history
1230            .remove_from_redo(transaction_id)
1231            .iter()
1232            .map(|entry| entry.transaction.clone())
1233            .collect::<Vec<_>>();
1234
1235        transactions
1236            .into_iter()
1237            .map(|transaction| self.undo_or_redo(transaction).unwrap())
1238            .collect()
1239    }
1240
1241    fn undo_or_redo(&mut self, transaction: Transaction) -> Result<Operation> {
1242        let mut counts = HashMap::default();
1243        for edit_id in transaction.edit_ids {
1244            counts.insert(edit_id, self.undo_map.undo_count(edit_id) + 1);
1245        }
1246
1247        let undo = UndoOperation {
1248            timestamp: self.lamport_clock.tick(),
1249            version: self.version(),
1250            counts,
1251        };
1252        self.apply_undo(&undo)?;
1253        self.snapshot.version.observe(undo.timestamp);
1254        let operation = Operation::Undo(undo);
1255        self.history.push(operation.clone());
1256        Ok(operation)
1257    }
1258
1259    pub fn push_transaction(&mut self, transaction: Transaction, now: Instant) {
1260        self.history.push_transaction(transaction, now);
1261        self.history.finalize_last_transaction();
1262    }
1263
1264    pub fn edited_ranges_for_transaction<'a, D>(
1265        &'a self,
1266        transaction: &'a Transaction,
1267    ) -> impl 'a + Iterator<Item = Range<D>>
1268    where
1269        D: TextDimension,
1270    {
1271        // get fragment ranges
1272        let mut cursor = self.fragments.cursor::<(Option<&Locator>, usize)>();
1273        let offset_ranges = self
1274            .fragment_ids_for_edits(transaction.edit_ids.iter())
1275            .into_iter()
1276            .filter_map(move |fragment_id| {
1277                cursor.seek_forward(&Some(fragment_id), Bias::Left, &None);
1278                let fragment = cursor.item()?;
1279                let start_offset = cursor.start().1;
1280                let end_offset = start_offset + if fragment.visible { fragment.len } else { 0 };
1281                Some(start_offset..end_offset)
1282            });
1283
1284        // combine adjacent ranges
1285        let mut prev_range: Option<Range<usize>> = None;
1286        let disjoint_ranges = offset_ranges
1287            .map(Some)
1288            .chain([None])
1289            .filter_map(move |range| {
1290                if let Some((range, prev_range)) = range.as_ref().zip(prev_range.as_mut()) {
1291                    if prev_range.end == range.start {
1292                        prev_range.end = range.end;
1293                        return None;
1294                    }
1295                }
1296                let result = prev_range.clone();
1297                prev_range = range;
1298                result
1299            });
1300
1301        // convert to the desired text dimension.
1302        let mut position = D::default();
1303        let mut rope_cursor = self.visible_text.cursor(0);
1304        disjoint_ranges.map(move |range| {
1305            position.add_assign(&rope_cursor.summary(range.start));
1306            let start = position.clone();
1307            position.add_assign(&rope_cursor.summary(range.end));
1308            let end = position.clone();
1309            start..end
1310        })
1311    }
1312
1313    pub fn subscribe(&mut self) -> Subscription {
1314        self.subscriptions.subscribe()
1315    }
1316
1317    pub fn wait_for_edits(
1318        &mut self,
1319        edit_ids: impl IntoIterator<Item = clock::Lamport>,
1320    ) -> impl 'static + Future<Output = Result<()>> {
1321        let mut futures = Vec::new();
1322        for edit_id in edit_ids {
1323            if !self.version.observed(edit_id) {
1324                let (tx, rx) = oneshot::channel();
1325                self.edit_id_resolvers.entry(edit_id).or_default().push(tx);
1326                futures.push(rx);
1327            }
1328        }
1329
1330        async move {
1331            for mut future in futures {
1332                if future.recv().await.is_none() {
1333                    Err(anyhow!("gave up waiting for edits"))?;
1334                }
1335            }
1336            Ok(())
1337        }
1338    }
1339
1340    pub fn wait_for_anchors(
1341        &mut self,
1342        anchors: impl IntoIterator<Item = Anchor>,
1343    ) -> impl 'static + Future<Output = Result<()>> {
1344        let mut futures = Vec::new();
1345        for anchor in anchors {
1346            if !self.version.observed(anchor.timestamp)
1347                && anchor != Anchor::MAX
1348                && anchor != Anchor::MIN
1349            {
1350                let (tx, rx) = oneshot::channel();
1351                self.edit_id_resolvers
1352                    .entry(anchor.timestamp)
1353                    .or_default()
1354                    .push(tx);
1355                futures.push(rx);
1356            }
1357        }
1358
1359        async move {
1360            for mut future in futures {
1361                if future.recv().await.is_none() {
1362                    Err(anyhow!("gave up waiting for anchors"))?;
1363                }
1364            }
1365            Ok(())
1366        }
1367    }
1368
1369    pub fn wait_for_version(&mut self, version: clock::Global) -> impl Future<Output = Result<()>> {
1370        let mut rx = None;
1371        if !self.snapshot.version.observed_all(&version) {
1372            let channel = oneshot::channel();
1373            self.wait_for_version_txs.push((version, channel.0));
1374            rx = Some(channel.1);
1375        }
1376        async move {
1377            if let Some(mut rx) = rx {
1378                if rx.recv().await.is_none() {
1379                    Err(anyhow!("gave up waiting for version"))?;
1380                }
1381            }
1382            Ok(())
1383        }
1384    }
1385
1386    pub fn give_up_waiting(&mut self) {
1387        self.edit_id_resolvers.clear();
1388        self.wait_for_version_txs.clear();
1389    }
1390
1391    fn resolve_edit(&mut self, edit_id: clock::Lamport) {
1392        for mut tx in self
1393            .edit_id_resolvers
1394            .remove(&edit_id)
1395            .into_iter()
1396            .flatten()
1397        {
1398            tx.try_send(()).ok();
1399        }
1400    }
1401}
1402
1403#[cfg(any(test, feature = "test-support"))]
1404impl Buffer {
1405    pub fn edit_via_marked_text(&mut self, marked_string: &str) {
1406        let edits = self.edits_for_marked_text(marked_string);
1407        self.edit(edits);
1408    }
1409
1410    pub fn edits_for_marked_text(&self, marked_string: &str) -> Vec<(Range<usize>, String)> {
1411        let old_text = self.text();
1412        let (new_text, mut ranges) = util::test::marked_text_ranges(marked_string, false);
1413        if ranges.is_empty() {
1414            ranges.push(0..new_text.len());
1415        }
1416
1417        assert_eq!(
1418            old_text[..ranges[0].start],
1419            new_text[..ranges[0].start],
1420            "invalid edit"
1421        );
1422
1423        let mut delta = 0;
1424        let mut edits = Vec::new();
1425        let mut ranges = ranges.into_iter().peekable();
1426
1427        while let Some(inserted_range) = ranges.next() {
1428            let new_start = inserted_range.start;
1429            let old_start = (new_start as isize - delta) as usize;
1430
1431            let following_text = if let Some(next_range) = ranges.peek() {
1432                &new_text[inserted_range.end..next_range.start]
1433            } else {
1434                &new_text[inserted_range.end..]
1435            };
1436
1437            let inserted_len = inserted_range.len();
1438            let deleted_len = old_text[old_start..]
1439                .find(following_text)
1440                .expect("invalid edit");
1441
1442            let old_range = old_start..old_start + deleted_len;
1443            edits.push((old_range, new_text[inserted_range].to_string()));
1444            delta += inserted_len as isize - deleted_len as isize;
1445        }
1446
1447        assert_eq!(
1448            old_text.len() as isize + delta,
1449            new_text.len() as isize,
1450            "invalid edit"
1451        );
1452
1453        edits
1454    }
1455
1456    pub fn check_invariants(&self) {
1457        // Ensure every fragment is ordered by locator in the fragment tree and corresponds
1458        // to an insertion fragment in the insertions tree.
1459        let mut prev_fragment_id = Locator::min();
1460        for fragment in self.snapshot.fragments.items(&None) {
1461            assert!(fragment.id > prev_fragment_id);
1462            prev_fragment_id = fragment.id.clone();
1463
1464            let insertion_fragment = self
1465                .snapshot
1466                .insertions
1467                .get(
1468                    &InsertionFragmentKey {
1469                        timestamp: fragment.timestamp,
1470                        split_offset: fragment.insertion_offset,
1471                    },
1472                    &(),
1473                )
1474                .unwrap();
1475            assert_eq!(
1476                insertion_fragment.fragment_id, fragment.id,
1477                "fragment: {:?}\ninsertion: {:?}",
1478                fragment, insertion_fragment
1479            );
1480        }
1481
1482        let mut cursor = self.snapshot.fragments.cursor::<Option<&Locator>>();
1483        for insertion_fragment in self.snapshot.insertions.cursor::<()>() {
1484            cursor.seek(&Some(&insertion_fragment.fragment_id), Bias::Left, &None);
1485            let fragment = cursor.item().unwrap();
1486            assert_eq!(insertion_fragment.fragment_id, fragment.id);
1487            assert_eq!(insertion_fragment.split_offset, fragment.insertion_offset);
1488        }
1489
1490        let fragment_summary = self.snapshot.fragments.summary();
1491        assert_eq!(
1492            fragment_summary.text.visible,
1493            self.snapshot.visible_text.len()
1494        );
1495        assert_eq!(
1496            fragment_summary.text.deleted,
1497            self.snapshot.deleted_text.len()
1498        );
1499
1500        assert!(!self.text().contains("\r\n"));
1501    }
1502
1503    pub fn set_group_interval(&mut self, group_interval: Duration) {
1504        self.history.group_interval = group_interval;
1505    }
1506
1507    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
1508        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
1509        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
1510        start..end
1511    }
1512
1513    pub fn get_random_edits<T>(
1514        &self,
1515        rng: &mut T,
1516        edit_count: usize,
1517    ) -> Vec<(Range<usize>, Arc<str>)>
1518    where
1519        T: rand::Rng,
1520    {
1521        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
1522        let mut last_end = None;
1523        for _ in 0..edit_count {
1524            if last_end.map_or(false, |last_end| last_end >= self.len()) {
1525                break;
1526            }
1527            let new_start = last_end.map_or(0, |last_end| last_end + 1);
1528            let range = self.random_byte_range(new_start, rng);
1529            last_end = Some(range.end);
1530
1531            let new_text_len = rng.gen_range(0..10);
1532            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
1533
1534            edits.push((range, new_text.into()));
1535        }
1536        edits
1537    }
1538
1539    #[allow(clippy::type_complexity)]
1540    pub fn randomly_edit<T>(
1541        &mut self,
1542        rng: &mut T,
1543        edit_count: usize,
1544    ) -> (Vec<(Range<usize>, Arc<str>)>, Operation)
1545    where
1546        T: rand::Rng,
1547    {
1548        let mut edits = self.get_random_edits(rng, edit_count);
1549        log::info!("mutating buffer {} with {:?}", self.replica_id, edits);
1550
1551        let op = self.edit(edits.iter().cloned());
1552        if let Operation::Edit(edit) = &op {
1553            assert_eq!(edits.len(), edit.new_text.len());
1554            for (edit, new_text) in edits.iter_mut().zip(&edit.new_text) {
1555                edit.1 = new_text.clone();
1556            }
1557        } else {
1558            unreachable!()
1559        }
1560
1561        (edits, op)
1562    }
1563
1564    pub fn randomly_undo_redo(&mut self, rng: &mut impl rand::Rng) -> Vec<Operation> {
1565        use rand::prelude::*;
1566
1567        let mut ops = Vec::new();
1568        for _ in 0..rng.gen_range(1..=5) {
1569            if let Some(entry) = self.history.undo_stack.choose(rng) {
1570                let transaction = entry.transaction.clone();
1571                log::info!(
1572                    "undoing buffer {} transaction {:?}",
1573                    self.replica_id,
1574                    transaction
1575                );
1576                ops.push(self.undo_or_redo(transaction).unwrap());
1577            }
1578        }
1579        ops
1580    }
1581}
1582
1583impl Deref for Buffer {
1584    type Target = BufferSnapshot;
1585
1586    fn deref(&self) -> &Self::Target {
1587        &self.snapshot
1588    }
1589}
1590
1591impl BufferSnapshot {
1592    pub fn as_rope(&self) -> &Rope {
1593        &self.visible_text
1594    }
1595
1596    pub fn remote_id(&self) -> u64 {
1597        self.remote_id
1598    }
1599
1600    pub fn replica_id(&self) -> ReplicaId {
1601        self.replica_id
1602    }
1603
1604    pub fn row_count(&self) -> u32 {
1605        self.max_point().row + 1
1606    }
1607
1608    pub fn len(&self) -> usize {
1609        self.visible_text.len()
1610    }
1611
1612    pub fn is_empty(&self) -> bool {
1613        self.len() == 0
1614    }
1615
1616    pub fn chars(&self) -> impl Iterator<Item = char> + '_ {
1617        self.chars_at(0)
1618    }
1619
1620    pub fn chars_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = char> + '_ {
1621        self.text_for_range(range).flat_map(str::chars)
1622    }
1623
1624    pub fn reversed_chars_for_range<T: ToOffset>(
1625        &self,
1626        range: Range<T>,
1627    ) -> impl Iterator<Item = char> + '_ {
1628        self.reversed_chunks_in_range(range)
1629            .flat_map(|chunk| chunk.chars().rev())
1630    }
1631
1632    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
1633    where
1634        T: ToOffset,
1635    {
1636        let position = position.to_offset(self);
1637        position == self.clip_offset(position, Bias::Left)
1638            && self
1639                .bytes_in_range(position..self.len())
1640                .flatten()
1641                .copied()
1642                .take(needle.len())
1643                .eq(needle.bytes())
1644    }
1645
1646    pub fn common_prefix_at<T>(&self, position: T, needle: &str) -> Range<T>
1647    where
1648        T: ToOffset + TextDimension,
1649    {
1650        let offset = position.to_offset(self);
1651        let common_prefix_len = needle
1652            .char_indices()
1653            .map(|(index, _)| index)
1654            .chain([needle.len()])
1655            .take_while(|&len| len <= offset)
1656            .filter(|&len| {
1657                let left = self
1658                    .chars_for_range(offset - len..offset)
1659                    .flat_map(char::to_lowercase);
1660                let right = needle[..len].chars().flat_map(char::to_lowercase);
1661                left.eq(right)
1662            })
1663            .last()
1664            .unwrap_or(0);
1665        let start_offset = offset - common_prefix_len;
1666        let start = self.text_summary_for_range(0..start_offset);
1667        start..position
1668    }
1669
1670    pub fn text(&self) -> String {
1671        self.visible_text.to_string()
1672    }
1673
1674    pub fn line_ending(&self) -> LineEnding {
1675        self.line_ending
1676    }
1677
1678    pub fn deleted_text(&self) -> String {
1679        self.deleted_text.to_string()
1680    }
1681
1682    pub fn fragments(&self) -> impl Iterator<Item = &Fragment> {
1683        self.fragments.iter()
1684    }
1685
1686    pub fn text_summary(&self) -> TextSummary {
1687        self.visible_text.summary()
1688    }
1689
1690    pub fn max_point(&self) -> Point {
1691        self.visible_text.max_point()
1692    }
1693
1694    pub fn max_point_utf16(&self) -> PointUtf16 {
1695        self.visible_text.max_point_utf16()
1696    }
1697
1698    pub fn point_to_offset(&self, point: Point) -> usize {
1699        self.visible_text.point_to_offset(point)
1700    }
1701
1702    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
1703        self.visible_text.point_utf16_to_offset(point)
1704    }
1705
1706    pub fn unclipped_point_utf16_to_offset(&self, point: Unclipped<PointUtf16>) -> usize {
1707        self.visible_text.unclipped_point_utf16_to_offset(point)
1708    }
1709
1710    pub fn unclipped_point_utf16_to_point(&self, point: Unclipped<PointUtf16>) -> Point {
1711        self.visible_text.unclipped_point_utf16_to_point(point)
1712    }
1713
1714    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
1715        self.visible_text.offset_utf16_to_offset(offset)
1716    }
1717
1718    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
1719        self.visible_text.offset_to_offset_utf16(offset)
1720    }
1721
1722    pub fn offset_to_point(&self, offset: usize) -> Point {
1723        self.visible_text.offset_to_point(offset)
1724    }
1725
1726    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
1727        self.visible_text.offset_to_point_utf16(offset)
1728    }
1729
1730    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
1731        self.visible_text.point_to_point_utf16(point)
1732    }
1733
1734    pub fn version(&self) -> &clock::Global {
1735        &self.version
1736    }
1737
1738    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
1739        let offset = position.to_offset(self);
1740        self.visible_text.chars_at(offset)
1741    }
1742
1743    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
1744        let offset = position.to_offset(self);
1745        self.visible_text.reversed_chars_at(offset)
1746    }
1747
1748    pub fn reversed_chunks_in_range<T: ToOffset>(&self, range: Range<T>) -> rope::Chunks {
1749        let range = range.start.to_offset(self)..range.end.to_offset(self);
1750        self.visible_text.reversed_chunks_in_range(range)
1751    }
1752
1753    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> rope::Bytes<'_> {
1754        let start = range.start.to_offset(self);
1755        let end = range.end.to_offset(self);
1756        self.visible_text.bytes_in_range(start..end)
1757    }
1758
1759    pub fn reversed_bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> rope::Bytes<'_> {
1760        let start = range.start.to_offset(self);
1761        let end = range.end.to_offset(self);
1762        self.visible_text.reversed_bytes_in_range(start..end)
1763    }
1764
1765    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> Chunks<'_> {
1766        let start = range.start.to_offset(self);
1767        let end = range.end.to_offset(self);
1768        self.visible_text.chunks_in_range(start..end)
1769    }
1770
1771    pub fn line_len(&self, row: u32) -> u32 {
1772        let row_start_offset = Point::new(row, 0).to_offset(self);
1773        let row_end_offset = if row >= self.max_point().row {
1774            self.len()
1775        } else {
1776            Point::new(row + 1, 0).to_offset(self) - 1
1777        };
1778        (row_end_offset - row_start_offset) as u32
1779    }
1780
1781    pub fn is_line_blank(&self, row: u32) -> bool {
1782        self.text_for_range(Point::new(row, 0)..Point::new(row, self.line_len(row)))
1783            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
1784    }
1785
1786    pub fn text_summary_for_range<D, O: ToOffset>(&self, range: Range<O>) -> D
1787    where
1788        D: TextDimension,
1789    {
1790        self.visible_text
1791            .cursor(range.start.to_offset(self))
1792            .summary(range.end.to_offset(self))
1793    }
1794
1795    pub fn summaries_for_anchors<'a, D, A>(&'a self, anchors: A) -> impl 'a + Iterator<Item = D>
1796    where
1797        D: 'a + TextDimension,
1798        A: 'a + IntoIterator<Item = &'a Anchor>,
1799    {
1800        let anchors = anchors.into_iter();
1801        self.summaries_for_anchors_with_payload::<D, _, ()>(anchors.map(|a| (a, ())))
1802            .map(|d| d.0)
1803    }
1804
1805    pub fn summaries_for_anchors_with_payload<'a, D, A, T>(
1806        &'a self,
1807        anchors: A,
1808    ) -> impl 'a + Iterator<Item = (D, T)>
1809    where
1810        D: 'a + TextDimension,
1811        A: 'a + IntoIterator<Item = (&'a Anchor, T)>,
1812    {
1813        let anchors = anchors.into_iter();
1814        let mut insertion_cursor = self.insertions.cursor::<InsertionFragmentKey>();
1815        let mut fragment_cursor = self.fragments.cursor::<(Option<&Locator>, usize)>();
1816        let mut text_cursor = self.visible_text.cursor(0);
1817        let mut position = D::default();
1818
1819        anchors.map(move |(anchor, payload)| {
1820            if *anchor == Anchor::MIN {
1821                return (D::default(), payload);
1822            } else if *anchor == Anchor::MAX {
1823                return (D::from_text_summary(&self.visible_text.summary()), payload);
1824            }
1825
1826            let anchor_key = InsertionFragmentKey {
1827                timestamp: anchor.timestamp,
1828                split_offset: anchor.offset,
1829            };
1830            insertion_cursor.seek(&anchor_key, anchor.bias, &());
1831            if let Some(insertion) = insertion_cursor.item() {
1832                let comparison = sum_tree::KeyedItem::key(insertion).cmp(&anchor_key);
1833                if comparison == Ordering::Greater
1834                    || (anchor.bias == Bias::Left
1835                        && comparison == Ordering::Equal
1836                        && anchor.offset > 0)
1837                {
1838                    insertion_cursor.prev(&());
1839                }
1840            } else {
1841                insertion_cursor.prev(&());
1842            }
1843            let insertion = insertion_cursor.item().expect("invalid insertion");
1844            assert_eq!(insertion.timestamp, anchor.timestamp, "invalid insertion");
1845
1846            fragment_cursor.seek_forward(&Some(&insertion.fragment_id), Bias::Left, &None);
1847            let fragment = fragment_cursor.item().unwrap();
1848            let mut fragment_offset = fragment_cursor.start().1;
1849            if fragment.visible {
1850                fragment_offset += anchor.offset - insertion.split_offset;
1851            }
1852
1853            position.add_assign(&text_cursor.summary(fragment_offset));
1854            (position.clone(), payload)
1855        })
1856    }
1857
1858    fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
1859    where
1860        D: TextDimension,
1861    {
1862        if *anchor == Anchor::MIN {
1863            D::default()
1864        } else if *anchor == Anchor::MAX {
1865            D::from_text_summary(&self.visible_text.summary())
1866        } else {
1867            let anchor_key = InsertionFragmentKey {
1868                timestamp: anchor.timestamp,
1869                split_offset: anchor.offset,
1870            };
1871            let mut insertion_cursor = self.insertions.cursor::<InsertionFragmentKey>();
1872            insertion_cursor.seek(&anchor_key, anchor.bias, &());
1873            if let Some(insertion) = insertion_cursor.item() {
1874                let comparison = sum_tree::KeyedItem::key(insertion).cmp(&anchor_key);
1875                if comparison == Ordering::Greater
1876                    || (anchor.bias == Bias::Left
1877                        && comparison == Ordering::Equal
1878                        && anchor.offset > 0)
1879                {
1880                    insertion_cursor.prev(&());
1881                }
1882            } else {
1883                insertion_cursor.prev(&());
1884            }
1885            let insertion = insertion_cursor.item().expect("invalid insertion");
1886            assert_eq!(insertion.timestamp, anchor.timestamp, "invalid insertion");
1887
1888            let mut fragment_cursor = self.fragments.cursor::<(Option<&Locator>, usize)>();
1889            fragment_cursor.seek(&Some(&insertion.fragment_id), Bias::Left, &None);
1890            let fragment = fragment_cursor.item().unwrap();
1891            let mut fragment_offset = fragment_cursor.start().1;
1892            if fragment.visible {
1893                fragment_offset += anchor.offset - insertion.split_offset;
1894            }
1895            self.text_summary_for_range(0..fragment_offset)
1896        }
1897    }
1898
1899    fn fragment_id_for_anchor(&self, anchor: &Anchor) -> &Locator {
1900        if *anchor == Anchor::MIN {
1901            Locator::min_ref()
1902        } else if *anchor == Anchor::MAX {
1903            Locator::max_ref()
1904        } else {
1905            let anchor_key = InsertionFragmentKey {
1906                timestamp: anchor.timestamp,
1907                split_offset: anchor.offset,
1908            };
1909            let mut insertion_cursor = self.insertions.cursor::<InsertionFragmentKey>();
1910            insertion_cursor.seek(&anchor_key, anchor.bias, &());
1911            if let Some(insertion) = insertion_cursor.item() {
1912                let comparison = sum_tree::KeyedItem::key(insertion).cmp(&anchor_key);
1913                if comparison == Ordering::Greater
1914                    || (anchor.bias == Bias::Left
1915                        && comparison == Ordering::Equal
1916                        && anchor.offset > 0)
1917                {
1918                    insertion_cursor.prev(&());
1919                }
1920            } else {
1921                insertion_cursor.prev(&());
1922            }
1923            let insertion = insertion_cursor.item().expect("invalid insertion");
1924            debug_assert_eq!(insertion.timestamp, anchor.timestamp, "invalid insertion");
1925            &insertion.fragment_id
1926        }
1927    }
1928
1929    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
1930        self.anchor_at(position, Bias::Left)
1931    }
1932
1933    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
1934        self.anchor_at(position, Bias::Right)
1935    }
1936
1937    pub fn anchor_at<T: ToOffset>(&self, position: T, bias: Bias) -> Anchor {
1938        self.anchor_at_offset(position.to_offset(self), bias)
1939    }
1940
1941    fn anchor_at_offset(&self, offset: usize, bias: Bias) -> Anchor {
1942        if bias == Bias::Left && offset == 0 {
1943            Anchor::MIN
1944        } else if bias == Bias::Right && offset == self.len() {
1945            Anchor::MAX
1946        } else {
1947            let mut fragment_cursor = self.fragments.cursor::<usize>();
1948            fragment_cursor.seek(&offset, bias, &None);
1949            let fragment = fragment_cursor.item().unwrap();
1950            let overshoot = offset - *fragment_cursor.start();
1951            Anchor {
1952                timestamp: fragment.timestamp,
1953                offset: fragment.insertion_offset + overshoot,
1954                bias,
1955                buffer_id: Some(self.remote_id),
1956            }
1957        }
1958    }
1959
1960    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
1961        *anchor == Anchor::MIN
1962            || *anchor == Anchor::MAX
1963            || (Some(self.remote_id) == anchor.buffer_id && self.version.observed(anchor.timestamp))
1964    }
1965
1966    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
1967        self.visible_text.clip_offset(offset, bias)
1968    }
1969
1970    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1971        self.visible_text.clip_point(point, bias)
1972    }
1973
1974    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
1975        self.visible_text.clip_offset_utf16(offset, bias)
1976    }
1977
1978    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
1979        self.visible_text.clip_point_utf16(point, bias)
1980    }
1981
1982    pub fn edits_since<'a, D>(
1983        &'a self,
1984        since: &'a clock::Global,
1985    ) -> impl 'a + Iterator<Item = Edit<D>>
1986    where
1987        D: TextDimension + Ord,
1988    {
1989        self.edits_since_in_range(since, Anchor::MIN..Anchor::MAX)
1990    }
1991
1992    pub fn anchored_edits_since<'a, D>(
1993        &'a self,
1994        since: &'a clock::Global,
1995    ) -> impl 'a + Iterator<Item = (Edit<D>, Range<Anchor>)>
1996    where
1997        D: TextDimension + Ord,
1998    {
1999        self.anchored_edits_since_in_range(since, Anchor::MIN..Anchor::MAX)
2000    }
2001
2002    pub fn edits_since_in_range<'a, D>(
2003        &'a self,
2004        since: &'a clock::Global,
2005        range: Range<Anchor>,
2006    ) -> impl 'a + Iterator<Item = Edit<D>>
2007    where
2008        D: TextDimension + Ord,
2009    {
2010        self.anchored_edits_since_in_range(since, range)
2011            .map(|item| item.0)
2012    }
2013
2014    pub fn anchored_edits_since_in_range<'a, D>(
2015        &'a self,
2016        since: &'a clock::Global,
2017        range: Range<Anchor>,
2018    ) -> impl 'a + Iterator<Item = (Edit<D>, Range<Anchor>)>
2019    where
2020        D: TextDimension + Ord,
2021    {
2022        let fragments_cursor = if *since == self.version {
2023            None
2024        } else {
2025            let mut cursor = self
2026                .fragments
2027                .filter(move |summary| !since.observed_all(&summary.max_version));
2028            cursor.next(&None);
2029            Some(cursor)
2030        };
2031        let mut cursor = self
2032            .fragments
2033            .cursor::<(Option<&Locator>, FragmentTextSummary)>();
2034
2035        let start_fragment_id = self.fragment_id_for_anchor(&range.start);
2036        cursor.seek(&Some(start_fragment_id), Bias::Left, &None);
2037        let mut visible_start = cursor.start().1.visible;
2038        let mut deleted_start = cursor.start().1.deleted;
2039        if let Some(fragment) = cursor.item() {
2040            let overshoot = range.start.offset - fragment.insertion_offset;
2041            if fragment.visible {
2042                visible_start += overshoot;
2043            } else {
2044                deleted_start += overshoot;
2045            }
2046        }
2047        let end_fragment_id = self.fragment_id_for_anchor(&range.end);
2048
2049        Edits {
2050            visible_cursor: self.visible_text.cursor(visible_start),
2051            deleted_cursor: self.deleted_text.cursor(deleted_start),
2052            fragments_cursor,
2053            undos: &self.undo_map,
2054            since,
2055            old_end: Default::default(),
2056            new_end: Default::default(),
2057            range: (start_fragment_id, range.start.offset)..(end_fragment_id, range.end.offset),
2058            buffer_id: self.remote_id,
2059        }
2060    }
2061}
2062
2063struct RopeBuilder<'a> {
2064    old_visible_cursor: rope::Cursor<'a>,
2065    old_deleted_cursor: rope::Cursor<'a>,
2066    new_visible: Rope,
2067    new_deleted: Rope,
2068}
2069
2070impl<'a> RopeBuilder<'a> {
2071    fn new(old_visible_cursor: rope::Cursor<'a>, old_deleted_cursor: rope::Cursor<'a>) -> Self {
2072        Self {
2073            old_visible_cursor,
2074            old_deleted_cursor,
2075            new_visible: Rope::new(),
2076            new_deleted: Rope::new(),
2077        }
2078    }
2079
2080    fn append(&mut self, len: FragmentTextSummary) {
2081        self.push(len.visible, true, true);
2082        self.push(len.deleted, false, false);
2083    }
2084
2085    fn push_fragment(&mut self, fragment: &Fragment, was_visible: bool) {
2086        debug_assert!(fragment.len > 0);
2087        self.push(fragment.len, was_visible, fragment.visible)
2088    }
2089
2090    fn push(&mut self, len: usize, was_visible: bool, is_visible: bool) {
2091        let text = if was_visible {
2092            self.old_visible_cursor
2093                .slice(self.old_visible_cursor.offset() + len)
2094        } else {
2095            self.old_deleted_cursor
2096                .slice(self.old_deleted_cursor.offset() + len)
2097        };
2098        if is_visible {
2099            self.new_visible.append(text);
2100        } else {
2101            self.new_deleted.append(text);
2102        }
2103    }
2104
2105    fn push_str(&mut self, text: &str) {
2106        self.new_visible.push(text);
2107    }
2108
2109    fn finish(mut self) -> (Rope, Rope) {
2110        self.new_visible.append(self.old_visible_cursor.suffix());
2111        self.new_deleted.append(self.old_deleted_cursor.suffix());
2112        (self.new_visible, self.new_deleted)
2113    }
2114}
2115
2116impl<'a, D: TextDimension + Ord, F: FnMut(&FragmentSummary) -> bool> Iterator for Edits<'a, D, F> {
2117    type Item = (Edit<D>, Range<Anchor>);
2118
2119    fn next(&mut self) -> Option<Self::Item> {
2120        let mut pending_edit: Option<Self::Item> = None;
2121        let cursor = self.fragments_cursor.as_mut()?;
2122
2123        while let Some(fragment) = cursor.item() {
2124            if fragment.id < *self.range.start.0 {
2125                cursor.next(&None);
2126                continue;
2127            } else if fragment.id > *self.range.end.0 {
2128                break;
2129            }
2130
2131            if cursor.start().visible > self.visible_cursor.offset() {
2132                let summary = self.visible_cursor.summary(cursor.start().visible);
2133                self.old_end.add_assign(&summary);
2134                self.new_end.add_assign(&summary);
2135            }
2136
2137            if pending_edit
2138                .as_ref()
2139                .map_or(false, |(change, _)| change.new.end < self.new_end)
2140            {
2141                break;
2142            }
2143
2144            let start_anchor = Anchor {
2145                timestamp: fragment.timestamp,
2146                offset: fragment.insertion_offset,
2147                bias: Bias::Right,
2148                buffer_id: Some(self.buffer_id),
2149            };
2150            let end_anchor = Anchor {
2151                timestamp: fragment.timestamp,
2152                offset: fragment.insertion_offset + fragment.len,
2153                bias: Bias::Left,
2154                buffer_id: Some(self.buffer_id),
2155            };
2156
2157            if !fragment.was_visible(self.since, self.undos) && fragment.visible {
2158                let mut visible_end = cursor.end(&None).visible;
2159                if fragment.id == *self.range.end.0 {
2160                    visible_end = cmp::min(
2161                        visible_end,
2162                        cursor.start().visible + (self.range.end.1 - fragment.insertion_offset),
2163                    );
2164                }
2165
2166                let fragment_summary = self.visible_cursor.summary(visible_end);
2167                let mut new_end = self.new_end.clone();
2168                new_end.add_assign(&fragment_summary);
2169                if let Some((edit, range)) = pending_edit.as_mut() {
2170                    edit.new.end = new_end.clone();
2171                    range.end = end_anchor;
2172                } else {
2173                    pending_edit = Some((
2174                        Edit {
2175                            old: self.old_end.clone()..self.old_end.clone(),
2176                            new: self.new_end.clone()..new_end.clone(),
2177                        },
2178                        start_anchor..end_anchor,
2179                    ));
2180                }
2181
2182                self.new_end = new_end;
2183            } else if fragment.was_visible(self.since, self.undos) && !fragment.visible {
2184                let mut deleted_end = cursor.end(&None).deleted;
2185                if fragment.id == *self.range.end.0 {
2186                    deleted_end = cmp::min(
2187                        deleted_end,
2188                        cursor.start().deleted + (self.range.end.1 - fragment.insertion_offset),
2189                    );
2190                }
2191
2192                if cursor.start().deleted > self.deleted_cursor.offset() {
2193                    self.deleted_cursor.seek_forward(cursor.start().deleted);
2194                }
2195                let fragment_summary = self.deleted_cursor.summary(deleted_end);
2196                let mut old_end = self.old_end.clone();
2197                old_end.add_assign(&fragment_summary);
2198                if let Some((edit, range)) = pending_edit.as_mut() {
2199                    edit.old.end = old_end.clone();
2200                    range.end = end_anchor;
2201                } else {
2202                    pending_edit = Some((
2203                        Edit {
2204                            old: self.old_end.clone()..old_end.clone(),
2205                            new: self.new_end.clone()..self.new_end.clone(),
2206                        },
2207                        start_anchor..end_anchor,
2208                    ));
2209                }
2210
2211                self.old_end = old_end;
2212            }
2213
2214            cursor.next(&None);
2215        }
2216
2217        pending_edit
2218    }
2219}
2220
2221impl Fragment {
2222    fn insertion_slice(&self) -> InsertionSlice {
2223        InsertionSlice {
2224            insertion_id: self.timestamp,
2225            range: self.insertion_offset..self.insertion_offset + self.len,
2226        }
2227    }
2228
2229    fn is_visible(&self, undos: &UndoMap) -> bool {
2230        !undos.is_undone(self.timestamp) && self.deletions.iter().all(|d| undos.is_undone(*d))
2231    }
2232
2233    fn was_visible(&self, version: &clock::Global, undos: &UndoMap) -> bool {
2234        (version.observed(self.timestamp) && !undos.was_undone(self.timestamp, version))
2235            && self
2236                .deletions
2237                .iter()
2238                .all(|d| !version.observed(*d) || undos.was_undone(*d, version))
2239    }
2240}
2241
2242impl sum_tree::Item for Fragment {
2243    type Summary = FragmentSummary;
2244
2245    fn summary(&self) -> Self::Summary {
2246        let mut max_version = clock::Global::new();
2247        max_version.observe(self.timestamp);
2248        for deletion in &self.deletions {
2249            max_version.observe(*deletion);
2250        }
2251        max_version.join(&self.max_undos);
2252
2253        let mut min_insertion_version = clock::Global::new();
2254        min_insertion_version.observe(self.timestamp);
2255        let max_insertion_version = min_insertion_version.clone();
2256        if self.visible {
2257            FragmentSummary {
2258                max_id: self.id.clone(),
2259                text: FragmentTextSummary {
2260                    visible: self.len,
2261                    deleted: 0,
2262                },
2263                max_version,
2264                min_insertion_version,
2265                max_insertion_version,
2266            }
2267        } else {
2268            FragmentSummary {
2269                max_id: self.id.clone(),
2270                text: FragmentTextSummary {
2271                    visible: 0,
2272                    deleted: self.len,
2273                },
2274                max_version,
2275                min_insertion_version,
2276                max_insertion_version,
2277            }
2278        }
2279    }
2280}
2281
2282impl sum_tree::Summary for FragmentSummary {
2283    type Context = Option<clock::Global>;
2284
2285    fn add_summary(&mut self, other: &Self, _: &Self::Context) {
2286        self.max_id.assign(&other.max_id);
2287        self.text.visible += &other.text.visible;
2288        self.text.deleted += &other.text.deleted;
2289        self.max_version.join(&other.max_version);
2290        self.min_insertion_version
2291            .meet(&other.min_insertion_version);
2292        self.max_insertion_version
2293            .join(&other.max_insertion_version);
2294    }
2295}
2296
2297impl Default for FragmentSummary {
2298    fn default() -> Self {
2299        FragmentSummary {
2300            max_id: Locator::min(),
2301            text: FragmentTextSummary::default(),
2302            max_version: clock::Global::new(),
2303            min_insertion_version: clock::Global::new(),
2304            max_insertion_version: clock::Global::new(),
2305        }
2306    }
2307}
2308
2309impl sum_tree::Item for InsertionFragment {
2310    type Summary = InsertionFragmentKey;
2311
2312    fn summary(&self) -> Self::Summary {
2313        InsertionFragmentKey {
2314            timestamp: self.timestamp,
2315            split_offset: self.split_offset,
2316        }
2317    }
2318}
2319
2320impl sum_tree::KeyedItem for InsertionFragment {
2321    type Key = InsertionFragmentKey;
2322
2323    fn key(&self) -> Self::Key {
2324        sum_tree::Item::summary(self)
2325    }
2326}
2327
2328impl InsertionFragment {
2329    fn new(fragment: &Fragment) -> Self {
2330        Self {
2331            timestamp: fragment.timestamp,
2332            split_offset: fragment.insertion_offset,
2333            fragment_id: fragment.id.clone(),
2334        }
2335    }
2336
2337    fn insert_new(fragment: &Fragment) -> sum_tree::Edit<Self> {
2338        sum_tree::Edit::Insert(Self::new(fragment))
2339    }
2340}
2341
2342impl sum_tree::Summary for InsertionFragmentKey {
2343    type Context = ();
2344
2345    fn add_summary(&mut self, summary: &Self, _: &()) {
2346        *self = *summary;
2347    }
2348}
2349
2350#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
2351pub struct FullOffset(pub usize);
2352
2353impl ops::AddAssign<usize> for FullOffset {
2354    fn add_assign(&mut self, rhs: usize) {
2355        self.0 += rhs;
2356    }
2357}
2358
2359impl ops::Add<usize> for FullOffset {
2360    type Output = Self;
2361
2362    fn add(mut self, rhs: usize) -> Self::Output {
2363        self += rhs;
2364        self
2365    }
2366}
2367
2368impl ops::Sub for FullOffset {
2369    type Output = usize;
2370
2371    fn sub(self, rhs: Self) -> Self::Output {
2372        self.0 - rhs.0
2373    }
2374}
2375
2376impl<'a> sum_tree::Dimension<'a, FragmentSummary> for usize {
2377    fn add_summary(&mut self, summary: &FragmentSummary, _: &Option<clock::Global>) {
2378        *self += summary.text.visible;
2379    }
2380}
2381
2382impl<'a> sum_tree::Dimension<'a, FragmentSummary> for FullOffset {
2383    fn add_summary(&mut self, summary: &FragmentSummary, _: &Option<clock::Global>) {
2384        self.0 += summary.text.visible + summary.text.deleted;
2385    }
2386}
2387
2388impl<'a> sum_tree::Dimension<'a, FragmentSummary> for Option<&'a Locator> {
2389    fn add_summary(&mut self, summary: &'a FragmentSummary, _: &Option<clock::Global>) {
2390        *self = Some(&summary.max_id);
2391    }
2392}
2393
2394impl<'a> sum_tree::SeekTarget<'a, FragmentSummary, FragmentTextSummary> for usize {
2395    fn cmp(
2396        &self,
2397        cursor_location: &FragmentTextSummary,
2398        _: &Option<clock::Global>,
2399    ) -> cmp::Ordering {
2400        Ord::cmp(self, &cursor_location.visible)
2401    }
2402}
2403
2404#[derive(Copy, Clone, Debug, Eq, PartialEq)]
2405enum VersionedFullOffset {
2406    Offset(FullOffset),
2407    Invalid,
2408}
2409
2410impl VersionedFullOffset {
2411    fn full_offset(&self) -> FullOffset {
2412        if let Self::Offset(position) = self {
2413            *position
2414        } else {
2415            panic!("invalid version")
2416        }
2417    }
2418}
2419
2420impl Default for VersionedFullOffset {
2421    fn default() -> Self {
2422        Self::Offset(Default::default())
2423    }
2424}
2425
2426impl<'a> sum_tree::Dimension<'a, FragmentSummary> for VersionedFullOffset {
2427    fn add_summary(&mut self, summary: &'a FragmentSummary, cx: &Option<clock::Global>) {
2428        if let Self::Offset(offset) = self {
2429            let version = cx.as_ref().unwrap();
2430            if version.observed_all(&summary.max_insertion_version) {
2431                *offset += summary.text.visible + summary.text.deleted;
2432            } else if version.observed_any(&summary.min_insertion_version) {
2433                *self = Self::Invalid;
2434            }
2435        }
2436    }
2437}
2438
2439impl<'a> sum_tree::SeekTarget<'a, FragmentSummary, Self> for VersionedFullOffset {
2440    fn cmp(&self, cursor_position: &Self, _: &Option<clock::Global>) -> cmp::Ordering {
2441        match (self, cursor_position) {
2442            (Self::Offset(a), Self::Offset(b)) => Ord::cmp(a, b),
2443            (Self::Offset(_), Self::Invalid) => cmp::Ordering::Less,
2444            (Self::Invalid, _) => unreachable!(),
2445        }
2446    }
2447}
2448
2449impl Operation {
2450    fn replica_id(&self) -> ReplicaId {
2451        operation_queue::Operation::lamport_timestamp(self).replica_id
2452    }
2453
2454    pub fn timestamp(&self) -> clock::Lamport {
2455        match self {
2456            Operation::Edit(edit) => edit.timestamp,
2457            Operation::Undo(undo) => undo.timestamp,
2458        }
2459    }
2460
2461    pub fn as_edit(&self) -> Option<&EditOperation> {
2462        match self {
2463            Operation::Edit(edit) => Some(edit),
2464            _ => None,
2465        }
2466    }
2467
2468    pub fn is_edit(&self) -> bool {
2469        matches!(self, Operation::Edit { .. })
2470    }
2471}
2472
2473impl operation_queue::Operation for Operation {
2474    fn lamport_timestamp(&self) -> clock::Lamport {
2475        match self {
2476            Operation::Edit(edit) => edit.timestamp,
2477            Operation::Undo(undo) => undo.timestamp,
2478        }
2479    }
2480}
2481
2482pub trait ToOffset {
2483    fn to_offset(&self, snapshot: &BufferSnapshot) -> usize;
2484}
2485
2486impl ToOffset for Point {
2487    fn to_offset(&self, snapshot: &BufferSnapshot) -> usize {
2488        snapshot.point_to_offset(*self)
2489    }
2490}
2491
2492impl ToOffset for usize {
2493    fn to_offset(&self, snapshot: &BufferSnapshot) -> usize {
2494        assert!(
2495            *self <= snapshot.len(),
2496            "offset {} is out of range, max allowed is {}",
2497            self,
2498            snapshot.len()
2499        );
2500        *self
2501    }
2502}
2503
2504impl ToOffset for Anchor {
2505    fn to_offset(&self, snapshot: &BufferSnapshot) -> usize {
2506        snapshot.summary_for_anchor(self)
2507    }
2508}
2509
2510impl<'a, T: ToOffset> ToOffset for &'a T {
2511    fn to_offset(&self, content: &BufferSnapshot) -> usize {
2512        (*self).to_offset(content)
2513    }
2514}
2515
2516impl ToOffset for PointUtf16 {
2517    fn to_offset(&self, snapshot: &BufferSnapshot) -> usize {
2518        snapshot.point_utf16_to_offset(*self)
2519    }
2520}
2521
2522impl ToOffset for Unclipped<PointUtf16> {
2523    fn to_offset(&self, snapshot: &BufferSnapshot) -> usize {
2524        snapshot.unclipped_point_utf16_to_offset(*self)
2525    }
2526}
2527
2528pub trait ToPoint {
2529    fn to_point(&self, snapshot: &BufferSnapshot) -> Point;
2530}
2531
2532impl ToPoint for Anchor {
2533    fn to_point(&self, snapshot: &BufferSnapshot) -> Point {
2534        snapshot.summary_for_anchor(self)
2535    }
2536}
2537
2538impl ToPoint for usize {
2539    fn to_point(&self, snapshot: &BufferSnapshot) -> Point {
2540        snapshot.offset_to_point(*self)
2541    }
2542}
2543
2544impl ToPoint for Point {
2545    fn to_point(&self, _: &BufferSnapshot) -> Point {
2546        *self
2547    }
2548}
2549
2550impl ToPoint for Unclipped<PointUtf16> {
2551    fn to_point(&self, snapshot: &BufferSnapshot) -> Point {
2552        snapshot.unclipped_point_utf16_to_point(*self)
2553    }
2554}
2555
2556pub trait ToPointUtf16 {
2557    fn to_point_utf16(&self, snapshot: &BufferSnapshot) -> PointUtf16;
2558}
2559
2560impl ToPointUtf16 for Anchor {
2561    fn to_point_utf16(&self, snapshot: &BufferSnapshot) -> PointUtf16 {
2562        snapshot.summary_for_anchor(self)
2563    }
2564}
2565
2566impl ToPointUtf16 for usize {
2567    fn to_point_utf16(&self, snapshot: &BufferSnapshot) -> PointUtf16 {
2568        snapshot.offset_to_point_utf16(*self)
2569    }
2570}
2571
2572impl ToPointUtf16 for PointUtf16 {
2573    fn to_point_utf16(&self, _: &BufferSnapshot) -> PointUtf16 {
2574        *self
2575    }
2576}
2577
2578impl ToPointUtf16 for Point {
2579    fn to_point_utf16(&self, snapshot: &BufferSnapshot) -> PointUtf16 {
2580        snapshot.point_to_point_utf16(*self)
2581    }
2582}
2583
2584pub trait ToOffsetUtf16 {
2585    fn to_offset_utf16(&self, snapshot: &BufferSnapshot) -> OffsetUtf16;
2586}
2587
2588impl ToOffsetUtf16 for Anchor {
2589    fn to_offset_utf16(&self, snapshot: &BufferSnapshot) -> OffsetUtf16 {
2590        snapshot.summary_for_anchor(self)
2591    }
2592}
2593
2594impl ToOffsetUtf16 for usize {
2595    fn to_offset_utf16(&self, snapshot: &BufferSnapshot) -> OffsetUtf16 {
2596        snapshot.offset_to_offset_utf16(*self)
2597    }
2598}
2599
2600impl ToOffsetUtf16 for OffsetUtf16 {
2601    fn to_offset_utf16(&self, _snapshot: &BufferSnapshot) -> OffsetUtf16 {
2602        *self
2603    }
2604}
2605
2606pub trait FromAnchor {
2607    fn from_anchor(anchor: &Anchor, snapshot: &BufferSnapshot) -> Self;
2608}
2609
2610impl FromAnchor for Point {
2611    fn from_anchor(anchor: &Anchor, snapshot: &BufferSnapshot) -> Self {
2612        snapshot.summary_for_anchor(anchor)
2613    }
2614}
2615
2616impl FromAnchor for PointUtf16 {
2617    fn from_anchor(anchor: &Anchor, snapshot: &BufferSnapshot) -> Self {
2618        snapshot.summary_for_anchor(anchor)
2619    }
2620}
2621
2622impl FromAnchor for usize {
2623    fn from_anchor(anchor: &Anchor, snapshot: &BufferSnapshot) -> Self {
2624        snapshot.summary_for_anchor(anchor)
2625    }
2626}
2627
2628#[derive(Clone, Copy, Debug, PartialEq)]
2629pub enum LineEnding {
2630    Unix,
2631    Windows,
2632}
2633
2634impl Default for LineEnding {
2635    fn default() -> Self {
2636        #[cfg(unix)]
2637        return Self::Unix;
2638
2639        #[cfg(not(unix))]
2640        return Self::CRLF;
2641    }
2642}
2643
2644impl LineEnding {
2645    pub fn as_str(&self) -> &'static str {
2646        match self {
2647            LineEnding::Unix => "\n",
2648            LineEnding::Windows => "\r\n",
2649        }
2650    }
2651
2652    pub fn detect(text: &str) -> Self {
2653        let mut max_ix = cmp::min(text.len(), 1000);
2654        while !text.is_char_boundary(max_ix) {
2655            max_ix -= 1;
2656        }
2657
2658        if let Some(ix) = text[..max_ix].find(&['\n']) {
2659            if ix > 0 && text.as_bytes()[ix - 1] == b'\r' {
2660                Self::Windows
2661            } else {
2662                Self::Unix
2663            }
2664        } else {
2665            Self::default()
2666        }
2667    }
2668
2669    pub fn normalize(text: &mut String) {
2670        if let Cow::Owned(replaced) = LINE_SEPARATORS_REGEX.replace_all(text, "\n") {
2671            *text = replaced;
2672        }
2673    }
2674
2675    pub fn normalize_arc(text: Arc<str>) -> Arc<str> {
2676        if let Cow::Owned(replaced) = LINE_SEPARATORS_REGEX.replace_all(&text, "\n") {
2677            replaced.into()
2678        } else {
2679            text
2680        }
2681    }
2682}