lib.rs

   1mod anchor;
   2mod operation_queue;
   3mod point;
   4mod point_utf16;
   5#[cfg(any(test, feature = "test-support"))]
   6pub mod random_char_iter;
   7pub mod rope;
   8mod selection;
   9#[cfg(test)]
  10mod tests;
  11
  12pub use anchor::*;
  13use anyhow::{anyhow, Result};
  14use clock::ReplicaId;
  15use operation_queue::OperationQueue;
  16pub use point::*;
  17pub use point_utf16::*;
  18#[cfg(any(test, feature = "test-support"))]
  19pub use random_char_iter::*;
  20use rope::TextDimension;
  21pub use rope::{Chunks, Rope, TextSummary};
  22use rpc::proto;
  23pub use selection::*;
  24use std::{
  25    cmp::{self, Reverse},
  26    convert::TryFrom,
  27    iter::Iterator,
  28    ops::{self, Range},
  29    str,
  30    sync::Arc,
  31    time::{Duration, Instant},
  32};
  33pub use sum_tree::Bias;
  34use sum_tree::{FilterCursor, SumTree};
  35
  36#[cfg(any(test, feature = "test-support"))]
  37#[derive(Clone, Default)]
  38struct DeterministicState;
  39
  40#[cfg(any(test, feature = "test-support"))]
  41impl std::hash::BuildHasher for DeterministicState {
  42    type Hasher = seahash::SeaHasher;
  43
  44    fn build_hasher(&self) -> Self::Hasher {
  45        seahash::SeaHasher::new()
  46    }
  47}
  48
  49#[cfg(any(test, feature = "test-support"))]
  50type HashMap<K, V> = std::collections::HashMap<K, V, DeterministicState>;
  51
  52#[cfg(any(test, feature = "test-support"))]
  53type HashSet<T> = std::collections::HashSet<T, DeterministicState>;
  54
  55#[cfg(not(any(test, feature = "test-support")))]
  56type HashMap<K, V> = std::collections::HashMap<K, V>;
  57
  58#[cfg(not(any(test, feature = "test-support")))]
  59type HashSet<T> = std::collections::HashSet<T>;
  60
  61#[derive(Clone)]
  62pub struct Buffer {
  63    fragments: SumTree<Fragment>,
  64    visible_text: Rope,
  65    deleted_text: Rope,
  66    pub version: clock::Global,
  67    last_edit: clock::Local,
  68    undo_map: UndoMap,
  69    history: History,
  70    selections: HashMap<SelectionSetId, SelectionSet>,
  71    deferred_ops: OperationQueue,
  72    deferred_replicas: HashSet<ReplicaId>,
  73    replica_id: ReplicaId,
  74    remote_id: u64,
  75    local_clock: clock::Local,
  76    lamport_clock: clock::Lamport,
  77}
  78
  79#[derive(Clone, Debug)]
  80pub struct Transaction {
  81    start: clock::Global,
  82    end: clock::Global,
  83    edits: Vec<clock::Local>,
  84    ranges: Vec<Range<FullOffset>>,
  85    selections_before: HashMap<SelectionSetId, Arc<AnchorRangeMap<SelectionState>>>,
  86    selections_after: HashMap<SelectionSetId, Arc<AnchorRangeMap<SelectionState>>>,
  87    first_edit_at: Instant,
  88    last_edit_at: Instant,
  89}
  90
  91impl Transaction {
  92    pub fn starting_selection_set_ids<'a>(&'a self) -> impl Iterator<Item = SelectionSetId> + 'a {
  93        self.selections_before.keys().copied()
  94    }
  95
  96    fn push_edit(&mut self, edit: &EditOperation) {
  97        self.edits.push(edit.timestamp.local());
  98        self.end.observe(edit.timestamp.local());
  99
 100        let mut other_ranges = edit.ranges.iter().peekable();
 101        let mut new_ranges = Vec::new();
 102        let insertion_len = edit.new_text.as_ref().map_or(0, |t| t.len());
 103        let mut delta = 0;
 104
 105        for mut self_range in self.ranges.iter().cloned() {
 106            self_range.start += delta;
 107            self_range.end += delta;
 108
 109            while let Some(other_range) = other_ranges.peek() {
 110                let mut other_range = (*other_range).clone();
 111                other_range.start += delta;
 112                other_range.end += delta;
 113
 114                if other_range.start <= self_range.end {
 115                    other_ranges.next().unwrap();
 116                    delta += insertion_len;
 117
 118                    if other_range.end < self_range.start {
 119                        new_ranges.push(other_range.start..other_range.end + insertion_len);
 120                        self_range.start += insertion_len;
 121                        self_range.end += insertion_len;
 122                    } else {
 123                        self_range.start = cmp::min(self_range.start, other_range.start);
 124                        self_range.end = cmp::max(self_range.end, other_range.end) + insertion_len;
 125                    }
 126                } else {
 127                    break;
 128                }
 129            }
 130
 131            new_ranges.push(self_range);
 132        }
 133
 134        for other_range in other_ranges {
 135            new_ranges.push(other_range.start + delta..other_range.end + delta + insertion_len);
 136            delta += insertion_len;
 137        }
 138
 139        self.ranges = new_ranges;
 140    }
 141}
 142
 143#[derive(Clone)]
 144pub struct History {
 145    // TODO: Turn this into a String or Rope, maybe.
 146    pub base_text: Arc<str>,
 147    ops: HashMap<clock::Local, EditOperation>,
 148    undo_stack: Vec<Transaction>,
 149    redo_stack: Vec<Transaction>,
 150    transaction_depth: usize,
 151    group_interval: Duration,
 152}
 153
 154impl History {
 155    pub fn new(base_text: Arc<str>) -> Self {
 156        Self {
 157            base_text,
 158            ops: Default::default(),
 159            undo_stack: Vec::new(),
 160            redo_stack: Vec::new(),
 161            transaction_depth: 0,
 162            group_interval: Duration::from_millis(300),
 163        }
 164    }
 165
 166    fn push(&mut self, op: EditOperation) {
 167        self.ops.insert(op.timestamp.local(), op);
 168    }
 169
 170    fn start_transaction(
 171        &mut self,
 172        start: clock::Global,
 173        selections_before: HashMap<SelectionSetId, Arc<AnchorRangeMap<SelectionState>>>,
 174        now: Instant,
 175    ) {
 176        self.transaction_depth += 1;
 177        if self.transaction_depth == 1 {
 178            self.undo_stack.push(Transaction {
 179                start: start.clone(),
 180                end: start,
 181                edits: Vec::new(),
 182                ranges: Vec::new(),
 183                selections_before,
 184                selections_after: Default::default(),
 185                first_edit_at: now,
 186                last_edit_at: now,
 187            });
 188        }
 189    }
 190
 191    fn end_transaction(
 192        &mut self,
 193        selections_after: HashMap<SelectionSetId, Arc<AnchorRangeMap<SelectionState>>>,
 194        now: Instant,
 195    ) -> Option<&Transaction> {
 196        assert_ne!(self.transaction_depth, 0);
 197        self.transaction_depth -= 1;
 198        if self.transaction_depth == 0 {
 199            if self.undo_stack.last().unwrap().ranges.is_empty() {
 200                self.undo_stack.pop();
 201                None
 202            } else {
 203                let transaction = self.undo_stack.last_mut().unwrap();
 204                transaction.selections_after = selections_after;
 205                transaction.last_edit_at = now;
 206                Some(transaction)
 207            }
 208        } else {
 209            None
 210        }
 211    }
 212
 213    fn group(&mut self) {
 214        let mut new_len = self.undo_stack.len();
 215        let mut transactions = self.undo_stack.iter_mut();
 216
 217        if let Some(mut transaction) = transactions.next_back() {
 218            while let Some(prev_transaction) = transactions.next_back() {
 219                if transaction.first_edit_at - prev_transaction.last_edit_at <= self.group_interval
 220                    && transaction.start == prev_transaction.end
 221                {
 222                    transaction = prev_transaction;
 223                    new_len -= 1;
 224                } else {
 225                    break;
 226                }
 227            }
 228        }
 229
 230        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
 231        if let Some(last_transaction) = transactions_to_keep.last_mut() {
 232            for transaction in &*transactions_to_merge {
 233                for edit_id in &transaction.edits {
 234                    last_transaction.push_edit(&self.ops[edit_id]);
 235                }
 236            }
 237
 238            if let Some(transaction) = transactions_to_merge.last_mut() {
 239                last_transaction.last_edit_at = transaction.last_edit_at;
 240                last_transaction
 241                    .selections_after
 242                    .extend(transaction.selections_after.drain());
 243                last_transaction.end = transaction.end.clone();
 244            }
 245        }
 246
 247        self.undo_stack.truncate(new_len);
 248    }
 249
 250    fn push_undo(&mut self, edit_id: clock::Local) {
 251        assert_ne!(self.transaction_depth, 0);
 252        let last_transaction = self.undo_stack.last_mut().unwrap();
 253        last_transaction.push_edit(&self.ops[&edit_id]);
 254    }
 255
 256    fn pop_undo(&mut self) -> Option<&Transaction> {
 257        assert_eq!(self.transaction_depth, 0);
 258        if let Some(transaction) = self.undo_stack.pop() {
 259            self.redo_stack.push(transaction);
 260            self.redo_stack.last()
 261        } else {
 262            None
 263        }
 264    }
 265
 266    fn pop_redo(&mut self) -> Option<&Transaction> {
 267        assert_eq!(self.transaction_depth, 0);
 268        if let Some(transaction) = self.redo_stack.pop() {
 269            self.undo_stack.push(transaction);
 270            self.undo_stack.last()
 271        } else {
 272            None
 273        }
 274    }
 275}
 276
 277#[derive(Clone, Default, Debug)]
 278struct UndoMap(HashMap<clock::Local, Vec<(clock::Local, u32)>>);
 279
 280impl UndoMap {
 281    fn insert(&mut self, undo: &UndoOperation) {
 282        for (edit_id, count) in &undo.counts {
 283            self.0.entry(*edit_id).or_default().push((undo.id, *count));
 284        }
 285    }
 286
 287    fn is_undone(&self, edit_id: clock::Local) -> bool {
 288        self.undo_count(edit_id) % 2 == 1
 289    }
 290
 291    fn was_undone(&self, edit_id: clock::Local, version: &clock::Global) -> bool {
 292        let undo_count = self
 293            .0
 294            .get(&edit_id)
 295            .unwrap_or(&Vec::new())
 296            .iter()
 297            .filter(|(undo_id, _)| version.observed(*undo_id))
 298            .map(|(_, undo_count)| *undo_count)
 299            .max()
 300            .unwrap_or(0);
 301        undo_count % 2 == 1
 302    }
 303
 304    fn undo_count(&self, edit_id: clock::Local) -> u32 {
 305        self.0
 306            .get(&edit_id)
 307            .unwrap_or(&Vec::new())
 308            .iter()
 309            .map(|(_, undo_count)| *undo_count)
 310            .max()
 311            .unwrap_or(0)
 312    }
 313}
 314
 315struct Edits<'a, D: TextDimension<'a>, F: FnMut(&FragmentSummary) -> bool> {
 316    visible_cursor: rope::Cursor<'a>,
 317    deleted_cursor: rope::Cursor<'a>,
 318    fragments_cursor: Option<FilterCursor<'a, F, Fragment, FragmentTextSummary>>,
 319    undos: &'a UndoMap,
 320    since: &'a clock::Global,
 321    old_end: D,
 322    new_end: D,
 323}
 324
 325#[derive(Clone, Debug, Default, Eq, PartialEq)]
 326pub struct Edit<D> {
 327    pub old: Range<D>,
 328    pub new: Range<D>,
 329}
 330
 331impl<D1, D2> Edit<(D1, D2)> {
 332    pub fn flatten(self) -> (Edit<D1>, Edit<D2>) {
 333        (
 334            Edit {
 335                old: self.old.start.0..self.old.end.0,
 336                new: self.new.start.0..self.new.end.0,
 337            },
 338            Edit {
 339                old: self.old.start.1..self.old.end.1,
 340                new: self.new.start.1..self.new.end.1,
 341            },
 342        )
 343    }
 344}
 345
 346#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 347struct InsertionTimestamp {
 348    replica_id: ReplicaId,
 349    local: clock::Seq,
 350    lamport: clock::Seq,
 351}
 352
 353impl InsertionTimestamp {
 354    fn local(&self) -> clock::Local {
 355        clock::Local {
 356            replica_id: self.replica_id,
 357            value: self.local,
 358        }
 359    }
 360
 361    fn lamport(&self) -> clock::Lamport {
 362        clock::Lamport {
 363            replica_id: self.replica_id,
 364            value: self.lamport,
 365        }
 366    }
 367}
 368
 369#[derive(Eq, PartialEq, Clone, Debug)]
 370struct Fragment {
 371    timestamp: InsertionTimestamp,
 372    len: usize,
 373    visible: bool,
 374    deletions: HashSet<clock::Local>,
 375    max_undos: clock::Global,
 376}
 377
 378#[derive(Eq, PartialEq, Clone, Debug)]
 379pub struct FragmentSummary {
 380    text: FragmentTextSummary,
 381    max_version: clock::Global,
 382    min_insertion_version: clock::Global,
 383    max_insertion_version: clock::Global,
 384}
 385
 386#[derive(Copy, Default, Clone, Debug, PartialEq, Eq)]
 387struct FragmentTextSummary {
 388    visible: usize,
 389    deleted: usize,
 390}
 391
 392impl<'a> sum_tree::Dimension<'a, FragmentSummary> for FragmentTextSummary {
 393    fn add_summary(&mut self, summary: &'a FragmentSummary, _: &Option<clock::Global>) {
 394        self.visible += summary.text.visible;
 395        self.deleted += summary.text.deleted;
 396    }
 397}
 398
 399#[derive(Clone, Debug, Eq, PartialEq)]
 400pub enum Operation {
 401    Edit(EditOperation),
 402    Undo {
 403        undo: UndoOperation,
 404        lamport_timestamp: clock::Lamport,
 405    },
 406    UpdateSelections {
 407        set_id: SelectionSetId,
 408        selections: Arc<AnchorRangeMap<SelectionState>>,
 409        lamport_timestamp: clock::Lamport,
 410    },
 411    RemoveSelections {
 412        set_id: SelectionSetId,
 413        lamport_timestamp: clock::Lamport,
 414    },
 415    SetActiveSelections {
 416        set_id: Option<SelectionSetId>,
 417        lamport_timestamp: clock::Lamport,
 418    },
 419    #[cfg(test)]
 420    Test(clock::Lamport),
 421}
 422
 423#[derive(Clone, Debug, Eq, PartialEq)]
 424pub struct EditOperation {
 425    timestamp: InsertionTimestamp,
 426    version: clock::Global,
 427    ranges: Vec<Range<FullOffset>>,
 428    new_text: Option<String>,
 429}
 430
 431#[derive(Clone, Debug, Eq, PartialEq)]
 432pub struct UndoOperation {
 433    id: clock::Local,
 434    counts: HashMap<clock::Local, u32>,
 435    ranges: Vec<Range<FullOffset>>,
 436    version: clock::Global,
 437}
 438
 439impl Buffer {
 440    pub fn new(replica_id: u16, remote_id: u64, history: History) -> Buffer {
 441        let mut fragments = SumTree::new();
 442
 443        let visible_text = Rope::from(history.base_text.as_ref());
 444        if visible_text.len() > 0 {
 445            fragments.push(
 446                Fragment {
 447                    timestamp: Default::default(),
 448                    len: visible_text.len(),
 449                    visible: true,
 450                    deletions: Default::default(),
 451                    max_undos: Default::default(),
 452                },
 453                &None,
 454            );
 455        }
 456
 457        Buffer {
 458            visible_text,
 459            deleted_text: Rope::new(),
 460            fragments,
 461            version: clock::Global::new(),
 462            last_edit: clock::Local::default(),
 463            undo_map: Default::default(),
 464            history,
 465            selections: HashMap::default(),
 466            deferred_ops: OperationQueue::new(),
 467            deferred_replicas: HashSet::default(),
 468            replica_id,
 469            remote_id,
 470            local_clock: clock::Local::new(replica_id),
 471            lamport_clock: clock::Lamport::new(replica_id),
 472        }
 473    }
 474
 475    pub fn from_proto(replica_id: u16, message: proto::Buffer) -> Result<Self> {
 476        let mut buffer = Buffer::new(replica_id, message.id, History::new(message.content.into()));
 477        let ops = message
 478            .history
 479            .into_iter()
 480            .map(|op| Operation::Edit(op.into()));
 481        buffer.apply_ops(ops)?;
 482        buffer.selections = message
 483            .selections
 484            .into_iter()
 485            .map(|set| {
 486                let set = SelectionSet::try_from(set)?;
 487                Result::<_, anyhow::Error>::Ok((set.id, set))
 488            })
 489            .collect::<Result<_, _>>()?;
 490        Ok(buffer)
 491    }
 492
 493    pub fn to_proto(&self) -> proto::Buffer {
 494        let ops = self.history.ops.values().map(Into::into).collect();
 495        proto::Buffer {
 496            id: self.remote_id,
 497            content: self.history.base_text.to_string(),
 498            history: ops,
 499            selections: self.selections.iter().map(|(_, set)| set.into()).collect(),
 500        }
 501    }
 502
 503    pub fn version(&self) -> clock::Global {
 504        self.version.clone()
 505    }
 506
 507    pub fn snapshot(&self) -> Snapshot {
 508        Snapshot {
 509            visible_text: self.visible_text.clone(),
 510            deleted_text: self.deleted_text.clone(),
 511            undo_map: self.undo_map.clone(),
 512            fragments: self.fragments.clone(),
 513            version: self.version.clone(),
 514        }
 515    }
 516
 517    pub fn content<'a>(&'a self) -> Content<'a> {
 518        self.into()
 519    }
 520
 521    pub fn as_rope(&self) -> &Rope {
 522        &self.visible_text
 523    }
 524
 525    pub fn text_summary_for_range(&self, range: Range<usize>) -> TextSummary {
 526        self.content().text_summary_for_range(range)
 527    }
 528
 529    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
 530        self.anchor_at(position, Bias::Left)
 531    }
 532
 533    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
 534        self.anchor_at(position, Bias::Right)
 535    }
 536
 537    pub fn anchor_at<T: ToOffset>(&self, position: T, bias: Bias) -> Anchor {
 538        self.content().anchor_at(position, bias)
 539    }
 540
 541    pub fn anchor_range_set<E>(&self, entries: E) -> AnchorRangeSet
 542    where
 543        E: IntoIterator<Item = Range<(usize, Bias)>>,
 544    {
 545        self.content().anchor_range_set(entries)
 546    }
 547
 548    pub fn point_for_offset(&self, offset: usize) -> Result<Point> {
 549        self.content().point_for_offset(offset)
 550    }
 551
 552    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
 553        self.content().clip_point(point, bias)
 554    }
 555
 556    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
 557        self.visible_text.clip_offset(offset, bias)
 558    }
 559
 560    pub fn replica_id(&self) -> ReplicaId {
 561        self.local_clock.replica_id
 562    }
 563
 564    pub fn remote_id(&self) -> u64 {
 565        self.remote_id
 566    }
 567
 568    pub fn text_summary(&self) -> TextSummary {
 569        self.visible_text.summary()
 570    }
 571
 572    pub fn len(&self) -> usize {
 573        self.content().len()
 574    }
 575
 576    pub fn line_len(&self, row: u32) -> u32 {
 577        self.content().line_len(row)
 578    }
 579
 580    pub fn max_point(&self) -> Point {
 581        self.visible_text.max_point()
 582    }
 583
 584    pub fn row_count(&self) -> u32 {
 585        self.max_point().row + 1
 586    }
 587
 588    pub fn text(&self) -> String {
 589        self.text_for_range(0..self.len()).collect()
 590    }
 591
 592    pub fn text_for_range<'a, T: ToOffset>(&'a self, range: Range<T>) -> Chunks<'a> {
 593        self.content().text_for_range(range)
 594    }
 595
 596    pub fn chars(&self) -> impl Iterator<Item = char> + '_ {
 597        self.chars_at(0)
 598    }
 599
 600    pub fn chars_at<'a, T: 'a + ToOffset>(
 601        &'a self,
 602        position: T,
 603    ) -> impl Iterator<Item = char> + 'a {
 604        self.content().chars_at(position)
 605    }
 606
 607    pub fn reversed_chars_at<'a, T: 'a + ToOffset>(
 608        &'a self,
 609        position: T,
 610    ) -> impl Iterator<Item = char> + 'a {
 611        self.content().reversed_chars_at(position)
 612    }
 613
 614    pub fn chars_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = char> + '_ {
 615        self.text_for_range(range).flat_map(str::chars)
 616    }
 617
 618    pub fn bytes_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = u8> + '_ {
 619        let offset = position.to_offset(self);
 620        self.visible_text.bytes_at(offset)
 621    }
 622
 623    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
 624    where
 625        T: ToOffset,
 626    {
 627        let position = position.to_offset(self);
 628        position == self.clip_offset(position, Bias::Left)
 629            && self
 630                .bytes_at(position)
 631                .take(needle.len())
 632                .eq(needle.bytes())
 633    }
 634
 635    pub fn deferred_ops_len(&self) -> usize {
 636        self.deferred_ops.len()
 637    }
 638
 639    pub fn edit<R, I, S, T>(&mut self, ranges: R, new_text: T) -> EditOperation
 640    where
 641        R: IntoIterator<IntoIter = I>,
 642        I: ExactSizeIterator<Item = Range<S>>,
 643        S: ToOffset,
 644        T: Into<String>,
 645    {
 646        let new_text = new_text.into();
 647        let new_text_len = new_text.len();
 648        let new_text = if new_text_len > 0 {
 649            Some(new_text)
 650        } else {
 651            None
 652        };
 653
 654        self.start_transaction(None).unwrap();
 655        let timestamp = InsertionTimestamp {
 656            replica_id: self.replica_id,
 657            local: self.local_clock.tick().value,
 658            lamport: self.lamport_clock.tick().value,
 659        };
 660        let edit = self.apply_local_edit(ranges.into_iter(), new_text, timestamp);
 661
 662        self.history.push(edit.clone());
 663        self.history.push_undo(edit.timestamp.local());
 664        self.last_edit = edit.timestamp.local();
 665        self.version.observe(edit.timestamp.local());
 666        self.end_transaction(None);
 667        edit
 668    }
 669
 670    fn apply_local_edit<S: ToOffset>(
 671        &mut self,
 672        ranges: impl ExactSizeIterator<Item = Range<S>>,
 673        new_text: Option<String>,
 674        timestamp: InsertionTimestamp,
 675    ) -> EditOperation {
 676        let mut edit = EditOperation {
 677            timestamp,
 678            version: self.version(),
 679            ranges: Vec::with_capacity(ranges.len()),
 680            new_text: None,
 681        };
 682
 683        let mut ranges = ranges
 684            .map(|range| range.start.to_offset(&*self)..range.end.to_offset(&*self))
 685            .peekable();
 686
 687        let mut new_ropes =
 688            RopeBuilder::new(self.visible_text.cursor(0), self.deleted_text.cursor(0));
 689        let mut old_fragments = self.fragments.cursor::<FragmentTextSummary>();
 690        let mut new_fragments =
 691            old_fragments.slice(&ranges.peek().unwrap().start, Bias::Right, &None);
 692        new_ropes.push_tree(new_fragments.summary().text);
 693
 694        let mut fragment_start = old_fragments.start().visible;
 695        for range in ranges {
 696            let fragment_end = old_fragments.end(&None).visible;
 697
 698            // If the current fragment ends before this range, then jump ahead to the first fragment
 699            // that extends past the start of this range, reusing any intervening fragments.
 700            if fragment_end < range.start {
 701                // If the current fragment has been partially consumed, then consume the rest of it
 702                // and advance to the next fragment before slicing.
 703                if fragment_start > old_fragments.start().visible {
 704                    if fragment_end > fragment_start {
 705                        let mut suffix = old_fragments.item().unwrap().clone();
 706                        suffix.len = fragment_end - fragment_start;
 707                        new_ropes.push_fragment(&suffix, suffix.visible);
 708                        new_fragments.push(suffix, &None);
 709                    }
 710                    old_fragments.next(&None);
 711                }
 712
 713                let slice = old_fragments.slice(&range.start, Bias::Right, &None);
 714                new_ropes.push_tree(slice.summary().text);
 715                new_fragments.push_tree(slice, &None);
 716                fragment_start = old_fragments.start().visible;
 717            }
 718
 719            let full_range_start = FullOffset(range.start + old_fragments.start().deleted);
 720
 721            // Preserve any portion of the current fragment that precedes this range.
 722            if fragment_start < range.start {
 723                let mut prefix = old_fragments.item().unwrap().clone();
 724                prefix.len = range.start - fragment_start;
 725                new_ropes.push_fragment(&prefix, prefix.visible);
 726                new_fragments.push(prefix, &None);
 727                fragment_start = range.start;
 728            }
 729
 730            // Insert the new text before any existing fragments within the range.
 731            if let Some(new_text) = new_text.as_deref() {
 732                new_ropes.push_str(new_text);
 733                new_fragments.push(
 734                    Fragment {
 735                        timestamp,
 736                        len: new_text.len(),
 737                        deletions: Default::default(),
 738                        max_undos: Default::default(),
 739                        visible: true,
 740                    },
 741                    &None,
 742                );
 743            }
 744
 745            // Advance through every fragment that intersects this range, marking the intersecting
 746            // portions as deleted.
 747            while fragment_start < range.end {
 748                let fragment = old_fragments.item().unwrap();
 749                let fragment_end = old_fragments.end(&None).visible;
 750                let mut intersection = fragment.clone();
 751                let intersection_end = cmp::min(range.end, fragment_end);
 752                if fragment.visible {
 753                    intersection.len = intersection_end - fragment_start;
 754                    intersection.deletions.insert(timestamp.local());
 755                    intersection.visible = false;
 756                }
 757                if intersection.len > 0 {
 758                    new_ropes.push_fragment(&intersection, fragment.visible);
 759                    new_fragments.push(intersection, &None);
 760                    fragment_start = intersection_end;
 761                }
 762                if fragment_end <= range.end {
 763                    old_fragments.next(&None);
 764                }
 765            }
 766
 767            let full_range_end = FullOffset(range.end + old_fragments.start().deleted);
 768            edit.ranges.push(full_range_start..full_range_end);
 769        }
 770
 771        // If the current fragment has been partially consumed, then consume the rest of it
 772        // and advance to the next fragment before slicing.
 773        if fragment_start > old_fragments.start().visible {
 774            let fragment_end = old_fragments.end(&None).visible;
 775            if fragment_end > fragment_start {
 776                let mut suffix = old_fragments.item().unwrap().clone();
 777                suffix.len = fragment_end - fragment_start;
 778                new_ropes.push_fragment(&suffix, suffix.visible);
 779                new_fragments.push(suffix, &None);
 780            }
 781            old_fragments.next(&None);
 782        }
 783
 784        let suffix = old_fragments.suffix(&None);
 785        new_ropes.push_tree(suffix.summary().text);
 786        new_fragments.push_tree(suffix, &None);
 787        let (visible_text, deleted_text) = new_ropes.finish();
 788        drop(old_fragments);
 789
 790        self.fragments = new_fragments;
 791        self.visible_text = visible_text;
 792        self.deleted_text = deleted_text;
 793        edit.new_text = new_text;
 794        edit
 795    }
 796
 797    pub fn apply_ops<I: IntoIterator<Item = Operation>>(&mut self, ops: I) -> Result<()> {
 798        let mut deferred_ops = Vec::new();
 799        for op in ops {
 800            if self.can_apply_op(&op) {
 801                self.apply_op(op)?;
 802            } else {
 803                self.deferred_replicas.insert(op.replica_id());
 804                deferred_ops.push(op);
 805            }
 806        }
 807        self.deferred_ops.insert(deferred_ops);
 808        self.flush_deferred_ops()?;
 809        Ok(())
 810    }
 811
 812    fn apply_op(&mut self, op: Operation) -> Result<()> {
 813        match op {
 814            Operation::Edit(edit) => {
 815                if !self.version.observed(edit.timestamp.local()) {
 816                    self.apply_remote_edit(
 817                        &edit.version,
 818                        &edit.ranges,
 819                        edit.new_text.as_deref(),
 820                        edit.timestamp,
 821                    );
 822                    self.version.observe(edit.timestamp.local());
 823                    self.history.push(edit);
 824                }
 825            }
 826            Operation::Undo {
 827                undo,
 828                lamport_timestamp,
 829            } => {
 830                if !self.version.observed(undo.id) {
 831                    self.apply_undo(&undo)?;
 832                    self.version.observe(undo.id);
 833                    self.lamport_clock.observe(lamport_timestamp);
 834                }
 835            }
 836            Operation::UpdateSelections {
 837                set_id,
 838                selections,
 839                lamport_timestamp,
 840            } => {
 841                if let Some(set) = self.selections.get_mut(&set_id) {
 842                    set.selections = selections;
 843                } else {
 844                    self.selections.insert(
 845                        set_id,
 846                        SelectionSet {
 847                            id: set_id,
 848                            selections,
 849                            active: false,
 850                        },
 851                    );
 852                }
 853                self.lamport_clock.observe(lamport_timestamp);
 854            }
 855            Operation::RemoveSelections {
 856                set_id,
 857                lamport_timestamp,
 858            } => {
 859                self.selections.remove(&set_id);
 860                self.lamport_clock.observe(lamport_timestamp);
 861            }
 862            Operation::SetActiveSelections {
 863                set_id,
 864                lamport_timestamp,
 865            } => {
 866                for (id, set) in &mut self.selections {
 867                    if id.replica_id == lamport_timestamp.replica_id {
 868                        if Some(*id) == set_id {
 869                            set.active = true;
 870                        } else {
 871                            set.active = false;
 872                        }
 873                    }
 874                }
 875                self.lamport_clock.observe(lamport_timestamp);
 876            }
 877            #[cfg(test)]
 878            Operation::Test(_) => {}
 879        }
 880        Ok(())
 881    }
 882
 883    fn apply_remote_edit(
 884        &mut self,
 885        version: &clock::Global,
 886        ranges: &[Range<FullOffset>],
 887        new_text: Option<&str>,
 888        timestamp: InsertionTimestamp,
 889    ) {
 890        if ranges.is_empty() {
 891            return;
 892        }
 893
 894        let cx = Some(version.clone());
 895        let mut new_ropes =
 896            RopeBuilder::new(self.visible_text.cursor(0), self.deleted_text.cursor(0));
 897        let mut old_fragments = self.fragments.cursor::<VersionedFullOffset>();
 898        let mut new_fragments = old_fragments.slice(
 899            &VersionedFullOffset::Offset(ranges[0].start),
 900            Bias::Left,
 901            &cx,
 902        );
 903        new_ropes.push_tree(new_fragments.summary().text);
 904
 905        let mut fragment_start = old_fragments.start().full_offset();
 906        for range in ranges {
 907            let fragment_end = old_fragments.end(&cx).full_offset();
 908
 909            // If the current fragment ends before this range, then jump ahead to the first fragment
 910            // that extends past the start of this range, reusing any intervening fragments.
 911            if fragment_end < range.start {
 912                // If the current fragment has been partially consumed, then consume the rest of it
 913                // and advance to the next fragment before slicing.
 914                if fragment_start > old_fragments.start().full_offset() {
 915                    if fragment_end > fragment_start {
 916                        let mut suffix = old_fragments.item().unwrap().clone();
 917                        suffix.len = fragment_end.0 - fragment_start.0;
 918                        new_ropes.push_fragment(&suffix, suffix.visible);
 919                        new_fragments.push(suffix, &None);
 920                    }
 921                    old_fragments.next(&cx);
 922                }
 923
 924                let slice =
 925                    old_fragments.slice(&VersionedFullOffset::Offset(range.start), Bias::Left, &cx);
 926                new_ropes.push_tree(slice.summary().text);
 927                new_fragments.push_tree(slice, &None);
 928                fragment_start = old_fragments.start().full_offset();
 929            }
 930
 931            // If we are at the end of a non-concurrent fragment, advance to the next one.
 932            let fragment_end = old_fragments.end(&cx).full_offset();
 933            if fragment_end == range.start && fragment_end > fragment_start {
 934                let mut fragment = old_fragments.item().unwrap().clone();
 935                fragment.len = fragment_end.0 - fragment_start.0;
 936                new_ropes.push_fragment(&fragment, fragment.visible);
 937                new_fragments.push(fragment, &None);
 938                old_fragments.next(&cx);
 939                fragment_start = old_fragments.start().full_offset();
 940            }
 941
 942            // Skip over insertions that are concurrent to this edit, but have a lower lamport
 943            // timestamp.
 944            while let Some(fragment) = old_fragments.item() {
 945                if fragment_start == range.start
 946                    && fragment.timestamp.lamport() > timestamp.lamport()
 947                {
 948                    new_ropes.push_fragment(fragment, fragment.visible);
 949                    new_fragments.push(fragment.clone(), &None);
 950                    old_fragments.next(&cx);
 951                    debug_assert_eq!(fragment_start, range.start);
 952                } else {
 953                    break;
 954                }
 955            }
 956            debug_assert!(fragment_start <= range.start);
 957
 958            // Preserve any portion of the current fragment that precedes this range.
 959            if fragment_start < range.start {
 960                let mut prefix = old_fragments.item().unwrap().clone();
 961                prefix.len = range.start.0 - fragment_start.0;
 962                fragment_start = range.start;
 963                new_ropes.push_fragment(&prefix, prefix.visible);
 964                new_fragments.push(prefix, &None);
 965            }
 966
 967            // Insert the new text before any existing fragments within the range.
 968            if let Some(new_text) = new_text {
 969                new_ropes.push_str(new_text);
 970                new_fragments.push(
 971                    Fragment {
 972                        timestamp,
 973                        len: new_text.len(),
 974                        deletions: Default::default(),
 975                        max_undos: Default::default(),
 976                        visible: true,
 977                    },
 978                    &None,
 979                );
 980            }
 981
 982            // Advance through every fragment that intersects this range, marking the intersecting
 983            // portions as deleted.
 984            while fragment_start < range.end {
 985                let fragment = old_fragments.item().unwrap();
 986                let fragment_end = old_fragments.end(&cx).full_offset();
 987                let mut intersection = fragment.clone();
 988                let intersection_end = cmp::min(range.end, fragment_end);
 989                if fragment.was_visible(version, &self.undo_map) {
 990                    intersection.len = intersection_end.0 - fragment_start.0;
 991                    intersection.deletions.insert(timestamp.local());
 992                    intersection.visible = false;
 993                }
 994                if intersection.len > 0 {
 995                    new_ropes.push_fragment(&intersection, fragment.visible);
 996                    new_fragments.push(intersection, &None);
 997                    fragment_start = intersection_end;
 998                }
 999                if fragment_end <= range.end {
1000                    old_fragments.next(&cx);
1001                }
1002            }
1003        }
1004
1005        // If the current fragment has been partially consumed, then consume the rest of it
1006        // and advance to the next fragment before slicing.
1007        if fragment_start > old_fragments.start().full_offset() {
1008            let fragment_end = old_fragments.end(&cx).full_offset();
1009            if fragment_end > fragment_start {
1010                let mut suffix = old_fragments.item().unwrap().clone();
1011                suffix.len = fragment_end.0 - fragment_start.0;
1012                new_ropes.push_fragment(&suffix, suffix.visible);
1013                new_fragments.push(suffix, &None);
1014            }
1015            old_fragments.next(&cx);
1016        }
1017
1018        let suffix = old_fragments.suffix(&cx);
1019        new_ropes.push_tree(suffix.summary().text);
1020        new_fragments.push_tree(suffix, &None);
1021        let (visible_text, deleted_text) = new_ropes.finish();
1022        drop(old_fragments);
1023
1024        self.fragments = new_fragments;
1025        self.visible_text = visible_text;
1026        self.deleted_text = deleted_text;
1027        self.local_clock.observe(timestamp.local());
1028        self.lamport_clock.observe(timestamp.lamport());
1029    }
1030
1031    fn apply_undo(&mut self, undo: &UndoOperation) -> Result<()> {
1032        self.undo_map.insert(undo);
1033
1034        let mut cx = undo.version.clone();
1035        for edit_id in undo.counts.keys().copied() {
1036            cx.observe(edit_id);
1037        }
1038        let cx = Some(cx);
1039
1040        let mut old_fragments = self.fragments.cursor::<VersionedFullOffset>();
1041        let mut new_fragments = old_fragments.slice(
1042            &VersionedFullOffset::Offset(undo.ranges[0].start),
1043            Bias::Right,
1044            &cx,
1045        );
1046        let mut new_ropes =
1047            RopeBuilder::new(self.visible_text.cursor(0), self.deleted_text.cursor(0));
1048        new_ropes.push_tree(new_fragments.summary().text);
1049
1050        for range in &undo.ranges {
1051            let mut end_offset = old_fragments.end(&cx).full_offset();
1052
1053            if end_offset < range.start {
1054                let preceding_fragments = old_fragments.slice(
1055                    &VersionedFullOffset::Offset(range.start),
1056                    Bias::Right,
1057                    &cx,
1058                );
1059                new_ropes.push_tree(preceding_fragments.summary().text);
1060                new_fragments.push_tree(preceding_fragments, &None);
1061            }
1062
1063            while end_offset <= range.end {
1064                if let Some(fragment) = old_fragments.item() {
1065                    let mut fragment = fragment.clone();
1066                    let fragment_was_visible = fragment.visible;
1067
1068                    if fragment.was_visible(&undo.version, &self.undo_map)
1069                        || undo.counts.contains_key(&fragment.timestamp.local())
1070                    {
1071                        fragment.visible = fragment.is_visible(&self.undo_map);
1072                        fragment.max_undos.observe(undo.id);
1073                    }
1074                    new_ropes.push_fragment(&fragment, fragment_was_visible);
1075                    new_fragments.push(fragment, &None);
1076
1077                    old_fragments.next(&cx);
1078                    if end_offset == old_fragments.end(&cx).full_offset() {
1079                        let unseen_fragments = old_fragments.slice(
1080                            &VersionedFullOffset::Offset(end_offset),
1081                            Bias::Right,
1082                            &cx,
1083                        );
1084                        new_ropes.push_tree(unseen_fragments.summary().text);
1085                        new_fragments.push_tree(unseen_fragments, &None);
1086                    }
1087                    end_offset = old_fragments.end(&cx).full_offset();
1088                } else {
1089                    break;
1090                }
1091            }
1092        }
1093
1094        let suffix = old_fragments.suffix(&cx);
1095        new_ropes.push_tree(suffix.summary().text);
1096        new_fragments.push_tree(suffix, &None);
1097
1098        drop(old_fragments);
1099        let (visible_text, deleted_text) = new_ropes.finish();
1100        self.fragments = new_fragments;
1101        self.visible_text = visible_text;
1102        self.deleted_text = deleted_text;
1103        Ok(())
1104    }
1105
1106    fn flush_deferred_ops(&mut self) -> Result<()> {
1107        self.deferred_replicas.clear();
1108        let mut deferred_ops = Vec::new();
1109        for op in self.deferred_ops.drain().cursor().cloned() {
1110            if self.can_apply_op(&op) {
1111                self.apply_op(op)?;
1112            } else {
1113                self.deferred_replicas.insert(op.replica_id());
1114                deferred_ops.push(op);
1115            }
1116        }
1117        self.deferred_ops.insert(deferred_ops);
1118        Ok(())
1119    }
1120
1121    fn can_apply_op(&self, op: &Operation) -> bool {
1122        if self.deferred_replicas.contains(&op.replica_id()) {
1123            false
1124        } else {
1125            match op {
1126                Operation::Edit(edit) => self.version >= edit.version,
1127                Operation::Undo { undo, .. } => self.version >= undo.version,
1128                Operation::UpdateSelections { selections, .. } => {
1129                    self.version >= *selections.version()
1130                }
1131                Operation::RemoveSelections { .. } => true,
1132                Operation::SetActiveSelections { set_id, .. } => {
1133                    set_id.map_or(true, |set_id| self.selections.contains_key(&set_id))
1134                }
1135                #[cfg(test)]
1136                Operation::Test(_) => true,
1137            }
1138        }
1139    }
1140
1141    pub fn peek_undo_stack(&self) -> Option<&Transaction> {
1142        self.history.undo_stack.last()
1143    }
1144
1145    pub fn start_transaction(
1146        &mut self,
1147        selection_set_ids: impl IntoIterator<Item = SelectionSetId>,
1148    ) -> Result<()> {
1149        self.start_transaction_at(selection_set_ids, Instant::now())
1150    }
1151
1152    pub fn start_transaction_at(
1153        &mut self,
1154        selection_set_ids: impl IntoIterator<Item = SelectionSetId>,
1155        now: Instant,
1156    ) -> Result<()> {
1157        let selections = selection_set_ids
1158            .into_iter()
1159            .map(|set_id| {
1160                let set = self
1161                    .selections
1162                    .get(&set_id)
1163                    .expect("invalid selection set id");
1164                (set_id, set.selections.clone())
1165            })
1166            .collect();
1167        self.history
1168            .start_transaction(self.version.clone(), selections, now);
1169        Ok(())
1170    }
1171
1172    pub fn end_transaction(&mut self, selection_set_ids: impl IntoIterator<Item = SelectionSetId>) {
1173        self.end_transaction_at(selection_set_ids, Instant::now());
1174    }
1175
1176    pub fn end_transaction_at(
1177        &mut self,
1178        selection_set_ids: impl IntoIterator<Item = SelectionSetId>,
1179        now: Instant,
1180    ) -> Option<clock::Global> {
1181        let selections = selection_set_ids
1182            .into_iter()
1183            .map(|set_id| {
1184                let set = self
1185                    .selections
1186                    .get(&set_id)
1187                    .expect("invalid selection set id");
1188                (set_id, set.selections.clone())
1189            })
1190            .collect();
1191
1192        if let Some(transaction) = self.history.end_transaction(selections, now) {
1193            let since = transaction.start.clone();
1194            self.history.group();
1195            Some(since)
1196        } else {
1197            None
1198        }
1199    }
1200
1201    pub fn remove_peer(&mut self, replica_id: ReplicaId) {
1202        self.selections
1203            .retain(|set_id, _| set_id.replica_id != replica_id)
1204    }
1205
1206    pub fn undo(&mut self) -> Vec<Operation> {
1207        let mut ops = Vec::new();
1208        if let Some(transaction) = self.history.pop_undo().cloned() {
1209            let selections = transaction.selections_before.clone();
1210            ops.push(self.undo_or_redo(transaction).unwrap());
1211            for (set_id, selections) in selections {
1212                ops.extend(self.restore_selection_set(set_id, selections));
1213            }
1214        }
1215        ops
1216    }
1217
1218    pub fn redo(&mut self) -> Vec<Operation> {
1219        let mut ops = Vec::new();
1220        if let Some(transaction) = self.history.pop_redo().cloned() {
1221            let selections = transaction.selections_after.clone();
1222            ops.push(self.undo_or_redo(transaction).unwrap());
1223            for (set_id, selections) in selections {
1224                ops.extend(self.restore_selection_set(set_id, selections));
1225            }
1226        }
1227        ops
1228    }
1229
1230    fn undo_or_redo(&mut self, transaction: Transaction) -> Result<Operation> {
1231        let mut counts = HashMap::default();
1232        for edit_id in transaction.edits {
1233            counts.insert(edit_id, self.undo_map.undo_count(edit_id) + 1);
1234        }
1235
1236        let undo = UndoOperation {
1237            id: self.local_clock.tick(),
1238            counts,
1239            ranges: transaction.ranges,
1240            version: transaction.start.clone(),
1241        };
1242        self.apply_undo(&undo)?;
1243        self.version.observe(undo.id);
1244
1245        Ok(Operation::Undo {
1246            undo,
1247            lamport_timestamp: self.lamport_clock.tick(),
1248        })
1249    }
1250
1251    pub fn selection_set(&self, set_id: SelectionSetId) -> Result<&SelectionSet> {
1252        self.selections
1253            .get(&set_id)
1254            .ok_or_else(|| anyhow!("invalid selection set id {:?}", set_id))
1255    }
1256
1257    pub fn selection_sets(&self) -> impl Iterator<Item = (&SelectionSetId, &SelectionSet)> {
1258        self.selections.iter()
1259    }
1260
1261    fn build_selection_anchor_range_map<T: ToOffset>(
1262        &self,
1263        selections: &[Selection<T>],
1264    ) -> Arc<AnchorRangeMap<SelectionState>> {
1265        Arc::new(
1266            self.content()
1267                .anchor_range_map(selections.iter().map(|selection| {
1268                    let start = selection.start.to_offset(self);
1269                    let end = selection.end.to_offset(self);
1270                    let range = (start, Bias::Left)..(end, Bias::Left);
1271                    let state = SelectionState {
1272                        id: selection.id,
1273                        reversed: selection.reversed,
1274                        goal: selection.goal,
1275                    };
1276                    (range, state)
1277                })),
1278        )
1279    }
1280
1281    pub fn update_selection_set<T: ToOffset>(
1282        &mut self,
1283        set_id: SelectionSetId,
1284        selections: &[Selection<T>],
1285    ) -> Result<Operation> {
1286        let selections = self.build_selection_anchor_range_map(selections);
1287        let set = self
1288            .selections
1289            .get_mut(&set_id)
1290            .ok_or_else(|| anyhow!("invalid selection set id {:?}", set_id))?;
1291        set.selections = selections.clone();
1292        Ok(Operation::UpdateSelections {
1293            set_id,
1294            selections,
1295            lamport_timestamp: self.lamport_clock.tick(),
1296        })
1297    }
1298
1299    pub fn restore_selection_set(
1300        &mut self,
1301        set_id: SelectionSetId,
1302        selections: Arc<AnchorRangeMap<SelectionState>>,
1303    ) -> Result<Operation> {
1304        let set = self
1305            .selections
1306            .get_mut(&set_id)
1307            .ok_or_else(|| anyhow!("invalid selection set id {:?}", set_id))?;
1308        set.selections = selections.clone();
1309        Ok(Operation::UpdateSelections {
1310            set_id,
1311            selections,
1312            lamport_timestamp: self.lamport_clock.tick(),
1313        })
1314    }
1315
1316    pub fn add_selection_set<T: ToOffset>(&mut self, selections: &[Selection<T>]) -> Operation {
1317        let selections = self.build_selection_anchor_range_map(selections);
1318        let set_id = self.lamport_clock.tick();
1319        self.selections.insert(
1320            set_id,
1321            SelectionSet {
1322                id: set_id,
1323                selections: selections.clone(),
1324                active: false,
1325            },
1326        );
1327        Operation::UpdateSelections {
1328            set_id,
1329            selections,
1330            lamport_timestamp: set_id,
1331        }
1332    }
1333
1334    pub fn set_active_selection_set(
1335        &mut self,
1336        set_id: Option<SelectionSetId>,
1337    ) -> Result<Operation> {
1338        if let Some(set_id) = set_id {
1339            assert_eq!(set_id.replica_id, self.replica_id());
1340        }
1341
1342        for (id, set) in &mut self.selections {
1343            if id.replica_id == self.local_clock.replica_id {
1344                if Some(*id) == set_id {
1345                    set.active = true;
1346                } else {
1347                    set.active = false;
1348                }
1349            }
1350        }
1351
1352        Ok(Operation::SetActiveSelections {
1353            set_id,
1354            lamport_timestamp: self.lamport_clock.tick(),
1355        })
1356    }
1357
1358    pub fn remove_selection_set(&mut self, set_id: SelectionSetId) -> Result<Operation> {
1359        self.selections
1360            .remove(&set_id)
1361            .ok_or_else(|| anyhow!("invalid selection set id {:?}", set_id))?;
1362        Ok(Operation::RemoveSelections {
1363            set_id,
1364            lamport_timestamp: self.lamport_clock.tick(),
1365        })
1366    }
1367
1368    pub fn edits_since<'a, D>(
1369        &'a self,
1370        since: &'a clock::Global,
1371    ) -> impl 'a + Iterator<Item = Edit<D>>
1372    where
1373        D: 'a + TextDimension<'a> + Ord,
1374    {
1375        self.content().edits_since(since)
1376    }
1377}
1378
1379#[cfg(any(test, feature = "test-support"))]
1380impl Buffer {
1381    fn random_byte_range(&mut self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
1382        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
1383        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
1384        start..end
1385    }
1386
1387    pub fn randomly_edit<T>(
1388        &mut self,
1389        rng: &mut T,
1390        old_range_count: usize,
1391    ) -> (Vec<Range<usize>>, String, Operation)
1392    where
1393        T: rand::Rng,
1394    {
1395        let mut old_ranges: Vec<Range<usize>> = Vec::new();
1396        for _ in 0..old_range_count {
1397            let last_end = old_ranges.last().map_or(0, |last_range| last_range.end + 1);
1398            if last_end > self.len() {
1399                break;
1400            }
1401            old_ranges.push(self.random_byte_range(last_end, rng));
1402        }
1403        let new_text_len = rng.gen_range(0..10);
1404        let new_text: String = crate::random_char_iter::RandomCharIter::new(&mut *rng)
1405            .take(new_text_len)
1406            .collect();
1407        log::info!(
1408            "mutating buffer {} at {:?}: {:?}",
1409            self.replica_id,
1410            old_ranges,
1411            new_text
1412        );
1413        let op = self.edit(old_ranges.iter().cloned(), new_text.as_str());
1414        (old_ranges, new_text, Operation::Edit(op))
1415    }
1416
1417    pub fn randomly_mutate<T>(&mut self, rng: &mut T) -> Vec<Operation>
1418    where
1419        T: rand::Rng,
1420    {
1421        use rand::prelude::*;
1422
1423        let mut ops = vec![self.randomly_edit(rng, 5).2];
1424
1425        // Randomly add, remove or mutate selection sets.
1426        let replica_selection_sets = &self
1427            .selection_sets()
1428            .map(|(set_id, _)| *set_id)
1429            .filter(|set_id| self.replica_id == set_id.replica_id)
1430            .collect::<Vec<_>>();
1431        let set_id = replica_selection_sets.choose(rng);
1432        if set_id.is_some() && rng.gen_bool(1.0 / 6.0) {
1433            ops.push(self.remove_selection_set(*set_id.unwrap()).unwrap());
1434        } else {
1435            let mut ranges = Vec::new();
1436            for _ in 0..5 {
1437                ranges.push(self.random_byte_range(0, rng));
1438            }
1439            let new_selections = self.selections_from_ranges(ranges).unwrap();
1440
1441            let op = if set_id.is_none() || rng.gen_bool(1.0 / 5.0) {
1442                self.add_selection_set(&new_selections)
1443            } else {
1444                self.update_selection_set(*set_id.unwrap(), &new_selections)
1445                    .unwrap()
1446            };
1447            ops.push(op);
1448        }
1449
1450        ops
1451    }
1452
1453    pub fn randomly_undo_redo(&mut self, rng: &mut impl rand::Rng) -> Vec<Operation> {
1454        use rand::prelude::*;
1455
1456        let mut ops = Vec::new();
1457        for _ in 0..rng.gen_range(1..=5) {
1458            if let Some(transaction) = self.history.undo_stack.choose(rng).cloned() {
1459                log::info!(
1460                    "undoing buffer {} transaction {:?}",
1461                    self.replica_id,
1462                    transaction
1463                );
1464                ops.push(self.undo_or_redo(transaction).unwrap());
1465            }
1466        }
1467        ops
1468    }
1469
1470    fn selections_from_ranges<I>(&self, ranges: I) -> Result<Vec<Selection<usize>>>
1471    where
1472        I: IntoIterator<Item = Range<usize>>,
1473    {
1474        use std::sync::atomic::{self, AtomicUsize};
1475
1476        static NEXT_SELECTION_ID: AtomicUsize = AtomicUsize::new(0);
1477
1478        let mut ranges = ranges.into_iter().collect::<Vec<_>>();
1479        ranges.sort_unstable_by_key(|range| range.start);
1480
1481        let mut selections = Vec::<Selection<usize>>::with_capacity(ranges.len());
1482        for mut range in ranges {
1483            let mut reversed = false;
1484            if range.start > range.end {
1485                reversed = true;
1486                std::mem::swap(&mut range.start, &mut range.end);
1487            }
1488
1489            if let Some(selection) = selections.last_mut() {
1490                if selection.end >= range.start {
1491                    selection.end = range.end;
1492                    continue;
1493                }
1494            }
1495
1496            selections.push(Selection {
1497                id: NEXT_SELECTION_ID.fetch_add(1, atomic::Ordering::SeqCst),
1498                start: range.start,
1499                end: range.end,
1500                reversed,
1501                goal: SelectionGoal::None,
1502            });
1503        }
1504        Ok(selections)
1505    }
1506
1507    pub fn selection_ranges<'a>(&'a self, set_id: SelectionSetId) -> Result<Vec<Range<usize>>> {
1508        Ok(self
1509            .selection_set(set_id)?
1510            .offset_selections(self)
1511            .map(move |selection| {
1512                if selection.reversed {
1513                    selection.end..selection.start
1514                } else {
1515                    selection.start..selection.end
1516                }
1517            })
1518            .collect())
1519    }
1520
1521    pub fn all_selection_ranges<'a>(
1522        &'a self,
1523    ) -> impl 'a + Iterator<Item = (SelectionSetId, Vec<Range<usize>>)> {
1524        self.selections
1525            .keys()
1526            .map(move |set_id| (*set_id, self.selection_ranges(*set_id).unwrap()))
1527    }
1528}
1529
1530#[derive(Clone)]
1531pub struct Snapshot {
1532    visible_text: Rope,
1533    deleted_text: Rope,
1534    undo_map: UndoMap,
1535    fragments: SumTree<Fragment>,
1536    version: clock::Global,
1537}
1538
1539impl Snapshot {
1540    pub fn as_rope(&self) -> &Rope {
1541        &self.visible_text
1542    }
1543
1544    pub fn len(&self) -> usize {
1545        self.visible_text.len()
1546    }
1547
1548    pub fn line_len(&self, row: u32) -> u32 {
1549        self.content().line_len(row)
1550    }
1551
1552    pub fn indent_column_for_line(&self, row: u32) -> u32 {
1553        self.content().indent_column_for_line(row)
1554    }
1555
1556    pub fn text(&self) -> Rope {
1557        self.visible_text.clone()
1558    }
1559
1560    pub fn text_summary(&self) -> TextSummary {
1561        self.visible_text.summary()
1562    }
1563
1564    pub fn max_point(&self) -> Point {
1565        self.visible_text.max_point()
1566    }
1567
1568    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> Chunks {
1569        let range = range.start.to_offset(self)..range.end.to_offset(self);
1570        self.visible_text.chunks_in_range(range)
1571    }
1572
1573    pub fn text_summary_for_range<T>(&self, range: Range<T>) -> TextSummary
1574    where
1575        T: ToOffset,
1576    {
1577        let range = range.start.to_offset(self.content())..range.end.to_offset(self.content());
1578        self.content().text_summary_for_range(range)
1579    }
1580
1581    pub fn point_for_offset(&self, offset: usize) -> Result<Point> {
1582        self.content().point_for_offset(offset)
1583    }
1584
1585    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
1586        self.visible_text.clip_offset(offset, bias)
1587    }
1588
1589    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1590        self.visible_text.clip_point(point, bias)
1591    }
1592
1593    pub fn to_offset(&self, point: Point) -> usize {
1594        self.visible_text.point_to_offset(point)
1595    }
1596
1597    pub fn to_point(&self, offset: usize) -> Point {
1598        self.visible_text.offset_to_point(offset)
1599    }
1600
1601    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
1602        self.content().anchor_at(position, Bias::Left)
1603    }
1604
1605    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
1606        self.content().anchor_at(position, Bias::Right)
1607    }
1608
1609    pub fn edits_since<'a, D>(
1610        &'a self,
1611        since: &'a clock::Global,
1612    ) -> impl 'a + Iterator<Item = Edit<D>>
1613    where
1614        D: 'a + TextDimension<'a> + Ord,
1615    {
1616        self.content().edits_since(since)
1617    }
1618
1619    pub fn version(&self) -> &clock::Global {
1620        &self.version
1621    }
1622
1623    pub fn content(&self) -> Content {
1624        self.into()
1625    }
1626}
1627
1628#[derive(Clone)]
1629pub struct Content<'a> {
1630    visible_text: &'a Rope,
1631    deleted_text: &'a Rope,
1632    undo_map: &'a UndoMap,
1633    fragments: &'a SumTree<Fragment>,
1634    version: &'a clock::Global,
1635}
1636
1637impl<'a> From<&'a Snapshot> for Content<'a> {
1638    fn from(snapshot: &'a Snapshot) -> Self {
1639        Self {
1640            visible_text: &snapshot.visible_text,
1641            deleted_text: &snapshot.deleted_text,
1642            undo_map: &snapshot.undo_map,
1643            fragments: &snapshot.fragments,
1644            version: &snapshot.version,
1645        }
1646    }
1647}
1648
1649impl<'a> From<&'a Buffer> for Content<'a> {
1650    fn from(buffer: &'a Buffer) -> Self {
1651        Self {
1652            visible_text: &buffer.visible_text,
1653            deleted_text: &buffer.deleted_text,
1654            undo_map: &buffer.undo_map,
1655            fragments: &buffer.fragments,
1656            version: &buffer.version,
1657        }
1658    }
1659}
1660
1661impl<'a> From<&'a mut Buffer> for Content<'a> {
1662    fn from(buffer: &'a mut Buffer) -> Self {
1663        Self {
1664            visible_text: &buffer.visible_text,
1665            deleted_text: &buffer.deleted_text,
1666            undo_map: &buffer.undo_map,
1667            fragments: &buffer.fragments,
1668            version: &buffer.version,
1669        }
1670    }
1671}
1672
1673impl<'a> From<&'a Content<'a>> for Content<'a> {
1674    fn from(content: &'a Content) -> Self {
1675        Self {
1676            visible_text: &content.visible_text,
1677            deleted_text: &content.deleted_text,
1678            undo_map: &content.undo_map,
1679            fragments: &content.fragments,
1680            version: &content.version,
1681        }
1682    }
1683}
1684
1685impl<'a> Content<'a> {
1686    fn max_point(&self) -> Point {
1687        self.visible_text.max_point()
1688    }
1689
1690    fn len(&self) -> usize {
1691        self.fragments.extent::<usize>(&None)
1692    }
1693
1694    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + 'a {
1695        let offset = position.to_offset(self);
1696        self.visible_text.chars_at(offset)
1697    }
1698
1699    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + 'a {
1700        let offset = position.to_offset(self);
1701        self.visible_text.reversed_chars_at(offset)
1702    }
1703
1704    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> Chunks<'a> {
1705        let start = range.start.to_offset(self);
1706        let end = range.end.to_offset(self);
1707        self.visible_text.chunks_in_range(start..end)
1708    }
1709
1710    fn line_len(&self, row: u32) -> u32 {
1711        let row_start_offset = Point::new(row, 0).to_offset(self);
1712        let row_end_offset = if row >= self.max_point().row {
1713            self.len()
1714        } else {
1715            Point::new(row + 1, 0).to_offset(self) - 1
1716        };
1717        (row_end_offset - row_start_offset) as u32
1718    }
1719
1720    pub fn indent_column_for_line(&self, row: u32) -> u32 {
1721        let mut result = 0;
1722        for c in self.chars_at(Point::new(row, 0)) {
1723            if c == ' ' {
1724                result += 1;
1725            } else {
1726                break;
1727            }
1728        }
1729        result
1730    }
1731
1732    fn summary_for_anchor(&self, anchor: &Anchor) -> TextSummary {
1733        let cx = Some(anchor.version.clone());
1734        let mut cursor = self.fragments.cursor::<(VersionedFullOffset, usize)>();
1735        cursor.seek(
1736            &VersionedFullOffset::Offset(anchor.full_offset),
1737            anchor.bias,
1738            &cx,
1739        );
1740        let overshoot = if cursor.item().map_or(false, |fragment| fragment.visible) {
1741            anchor.full_offset - cursor.start().0.full_offset()
1742        } else {
1743            0
1744        };
1745        self.text_summary_for_range(0..cursor.start().1 + overshoot)
1746    }
1747
1748    fn text_summary_for_range(&self, range: Range<usize>) -> TextSummary {
1749        self.visible_text.cursor(range.start).summary(range.end)
1750    }
1751
1752    fn summaries_for_anchors<T>(
1753        &self,
1754        map: &'a AnchorMap<T>,
1755    ) -> impl Iterator<Item = (TextSummary, &'a T)> {
1756        let cx = Some(map.version.clone());
1757        let mut summary = TextSummary::default();
1758        let mut rope_cursor = self.visible_text.cursor(0);
1759        let mut cursor = self.fragments.cursor::<(VersionedFullOffset, usize)>();
1760        map.entries.iter().map(move |((offset, bias), value)| {
1761            cursor.seek_forward(&VersionedFullOffset::Offset(*offset), *bias, &cx);
1762            let overshoot = if cursor.item().map_or(false, |fragment| fragment.visible) {
1763                *offset - cursor.start().0.full_offset()
1764            } else {
1765                0
1766            };
1767            summary += rope_cursor.summary::<TextSummary>(cursor.start().1 + overshoot);
1768            (summary.clone(), value)
1769        })
1770    }
1771
1772    fn summaries_for_anchor_ranges<T>(
1773        &self,
1774        map: &'a AnchorRangeMap<T>,
1775    ) -> impl Iterator<Item = (Range<TextSummary>, &'a T)> {
1776        let cx = Some(map.version.clone());
1777        let mut summary = TextSummary::default();
1778        let mut rope_cursor = self.visible_text.cursor(0);
1779        let mut cursor = self.fragments.cursor::<(VersionedFullOffset, usize)>();
1780        map.entries.iter().map(move |(range, value)| {
1781            let Range {
1782                start: (start_offset, start_bias),
1783                end: (end_offset, end_bias),
1784            } = range;
1785
1786            cursor.seek_forward(
1787                &VersionedFullOffset::Offset(*start_offset),
1788                *start_bias,
1789                &cx,
1790            );
1791            let overshoot = if cursor.item().map_or(false, |fragment| fragment.visible) {
1792                *start_offset - cursor.start().0.full_offset()
1793            } else {
1794                0
1795            };
1796            summary += rope_cursor.summary::<TextSummary>(cursor.start().1 + overshoot);
1797            let start_summary = summary.clone();
1798
1799            cursor.seek_forward(&VersionedFullOffset::Offset(*end_offset), *end_bias, &cx);
1800            let overshoot = if cursor.item().map_or(false, |fragment| fragment.visible) {
1801                *end_offset - cursor.start().0.full_offset()
1802            } else {
1803                0
1804            };
1805            summary += rope_cursor.summary::<TextSummary>(cursor.start().1 + overshoot);
1806            let end_summary = summary.clone();
1807
1808            (start_summary..end_summary, value)
1809        })
1810    }
1811
1812    fn anchor_at<T: ToOffset>(&self, position: T, bias: Bias) -> Anchor {
1813        Anchor {
1814            full_offset: position.to_full_offset(self, bias),
1815            bias,
1816            version: self.version.clone(),
1817        }
1818    }
1819
1820    pub fn anchor_map<T, E>(&self, entries: E) -> AnchorMap<T>
1821    where
1822        E: IntoIterator<Item = ((usize, Bias), T)>,
1823    {
1824        let version = self.version.clone();
1825        let mut cursor = self.fragments.cursor::<FragmentTextSummary>();
1826        let entries = entries
1827            .into_iter()
1828            .map(|((offset, bias), value)| {
1829                cursor.seek_forward(&offset, bias, &None);
1830                let full_offset = FullOffset(cursor.start().deleted + offset);
1831                ((full_offset, bias), value)
1832            })
1833            .collect();
1834
1835        AnchorMap { version, entries }
1836    }
1837
1838    pub fn anchor_range_map<T, E>(&self, entries: E) -> AnchorRangeMap<T>
1839    where
1840        E: IntoIterator<Item = (Range<(usize, Bias)>, T)>,
1841    {
1842        let version = self.version.clone();
1843        let mut cursor = self.fragments.cursor::<FragmentTextSummary>();
1844        let entries = entries
1845            .into_iter()
1846            .map(|(range, value)| {
1847                let Range {
1848                    start: (start_offset, start_bias),
1849                    end: (end_offset, end_bias),
1850                } = range;
1851                cursor.seek_forward(&start_offset, start_bias, &None);
1852                let full_start_offset = FullOffset(cursor.start().deleted + start_offset);
1853                cursor.seek_forward(&end_offset, end_bias, &None);
1854                let full_end_offset = FullOffset(cursor.start().deleted + end_offset);
1855                (
1856                    (full_start_offset, start_bias)..(full_end_offset, end_bias),
1857                    value,
1858                )
1859            })
1860            .collect();
1861
1862        AnchorRangeMap { version, entries }
1863    }
1864
1865    pub fn anchor_set<E>(&self, entries: E) -> AnchorSet
1866    where
1867        E: IntoIterator<Item = (usize, Bias)>,
1868    {
1869        AnchorSet(self.anchor_map(entries.into_iter().map(|range| (range, ()))))
1870    }
1871
1872    pub fn anchor_range_set<E>(&self, entries: E) -> AnchorRangeSet
1873    where
1874        E: IntoIterator<Item = Range<(usize, Bias)>>,
1875    {
1876        AnchorRangeSet(self.anchor_range_map(entries.into_iter().map(|range| (range, ()))))
1877    }
1878
1879    pub fn anchor_range_multimap<T, E, O>(
1880        &self,
1881        start_bias: Bias,
1882        end_bias: Bias,
1883        entries: E,
1884    ) -> AnchorRangeMultimap<T>
1885    where
1886        T: Clone,
1887        E: IntoIterator<Item = (Range<O>, T)>,
1888        O: ToOffset,
1889    {
1890        let mut entries = entries
1891            .into_iter()
1892            .map(|(range, value)| AnchorRangeMultimapEntry {
1893                range: FullOffsetRange {
1894                    start: range.start.to_full_offset(self, start_bias),
1895                    end: range.end.to_full_offset(self, end_bias),
1896                },
1897                value,
1898            })
1899            .collect::<Vec<_>>();
1900        entries.sort_unstable_by_key(|i| (i.range.start, Reverse(i.range.end)));
1901        AnchorRangeMultimap {
1902            entries: SumTree::from_iter(entries, &()),
1903            version: self.version.clone(),
1904            start_bias,
1905            end_bias,
1906        }
1907    }
1908
1909    fn full_offset_for_anchor(&self, anchor: &Anchor) -> FullOffset {
1910        let cx = Some(anchor.version.clone());
1911        let mut cursor = self
1912            .fragments
1913            .cursor::<(VersionedFullOffset, FragmentTextSummary)>();
1914        cursor.seek(
1915            &VersionedFullOffset::Offset(anchor.full_offset),
1916            anchor.bias,
1917            &cx,
1918        );
1919        let overshoot = if cursor.item().is_some() {
1920            anchor.full_offset - cursor.start().0.full_offset()
1921        } else {
1922            0
1923        };
1924        let summary = cursor.start().1;
1925        FullOffset(summary.visible + summary.deleted + overshoot)
1926    }
1927
1928    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
1929        self.visible_text.clip_point(point, bias)
1930    }
1931
1932    pub fn clip_point_utf16(&self, point: PointUtf16, bias: Bias) -> PointUtf16 {
1933        self.visible_text.clip_point_utf16(point, bias)
1934    }
1935
1936    fn point_for_offset(&self, offset: usize) -> Result<Point> {
1937        if offset <= self.len() {
1938            Ok(self.text_summary_for_range(0..offset).lines)
1939        } else {
1940            Err(anyhow!("offset out of bounds"))
1941        }
1942    }
1943
1944    pub fn edits_since<D>(&self, since: &'a clock::Global) -> impl 'a + Iterator<Item = Edit<D>>
1945    where
1946        D: 'a + TextDimension<'a> + Ord,
1947    {
1948        let fragments_cursor = if since == self.version {
1949            None
1950        } else {
1951            Some(self.fragments.filter(
1952                move |summary| summary.max_version.changed_since(since),
1953                &None,
1954            ))
1955        };
1956
1957        Edits {
1958            visible_cursor: self.visible_text.cursor(0),
1959            deleted_cursor: self.deleted_text.cursor(0),
1960            fragments_cursor,
1961            undos: &self.undo_map,
1962            since,
1963            old_end: Default::default(),
1964            new_end: Default::default(),
1965        }
1966    }
1967}
1968
1969struct RopeBuilder<'a> {
1970    old_visible_cursor: rope::Cursor<'a>,
1971    old_deleted_cursor: rope::Cursor<'a>,
1972    new_visible: Rope,
1973    new_deleted: Rope,
1974}
1975
1976impl<'a> RopeBuilder<'a> {
1977    fn new(old_visible_cursor: rope::Cursor<'a>, old_deleted_cursor: rope::Cursor<'a>) -> Self {
1978        Self {
1979            old_visible_cursor,
1980            old_deleted_cursor,
1981            new_visible: Rope::new(),
1982            new_deleted: Rope::new(),
1983        }
1984    }
1985
1986    fn push_tree(&mut self, len: FragmentTextSummary) {
1987        self.push(len.visible, true, true);
1988        self.push(len.deleted, false, false);
1989    }
1990
1991    fn push_fragment(&mut self, fragment: &Fragment, was_visible: bool) {
1992        debug_assert!(fragment.len > 0);
1993        self.push(fragment.len, was_visible, fragment.visible)
1994    }
1995
1996    fn push(&mut self, len: usize, was_visible: bool, is_visible: bool) {
1997        let text = if was_visible {
1998            self.old_visible_cursor
1999                .slice(self.old_visible_cursor.offset() + len)
2000        } else {
2001            self.old_deleted_cursor
2002                .slice(self.old_deleted_cursor.offset() + len)
2003        };
2004        if is_visible {
2005            self.new_visible.append(text);
2006        } else {
2007            self.new_deleted.append(text);
2008        }
2009    }
2010
2011    fn push_str(&mut self, text: &str) {
2012        self.new_visible.push(text);
2013    }
2014
2015    fn finish(mut self) -> (Rope, Rope) {
2016        self.new_visible.append(self.old_visible_cursor.suffix());
2017        self.new_deleted.append(self.old_deleted_cursor.suffix());
2018        (self.new_visible, self.new_deleted)
2019    }
2020}
2021
2022impl<'a, D: TextDimension<'a> + Ord, F: FnMut(&FragmentSummary) -> bool> Iterator
2023    for Edits<'a, D, F>
2024{
2025    type Item = Edit<D>;
2026
2027    fn next(&mut self) -> Option<Self::Item> {
2028        let mut pending_edit: Option<Edit<D>> = None;
2029        let cursor = self.fragments_cursor.as_mut()?;
2030
2031        while let Some(fragment) = cursor.item() {
2032            let summary = self.visible_cursor.summary(cursor.start().visible);
2033            self.old_end.add_assign(&summary);
2034            self.new_end.add_assign(&summary);
2035            if pending_edit
2036                .as_ref()
2037                .map_or(false, |change| change.new.end < self.new_end)
2038            {
2039                break;
2040            }
2041
2042            if !fragment.was_visible(&self.since, &self.undos) && fragment.visible {
2043                let fragment_summary = self.visible_cursor.summary(cursor.end(&None).visible);
2044                let mut new_end = self.new_end.clone();
2045                new_end.add_assign(&fragment_summary);
2046                if let Some(pending_edit) = pending_edit.as_mut() {
2047                    pending_edit.new.end = new_end.clone();
2048                } else {
2049                    pending_edit = Some(Edit {
2050                        old: self.old_end.clone()..self.old_end.clone(),
2051                        new: self.new_end.clone()..new_end.clone(),
2052                    });
2053                }
2054
2055                self.new_end = new_end;
2056            } else if fragment.was_visible(&self.since, &self.undos) && !fragment.visible {
2057                self.deleted_cursor.seek_forward(cursor.start().deleted);
2058                let fragment_summary = self.deleted_cursor.summary(cursor.end(&None).deleted);
2059                let mut old_end = self.old_end.clone();
2060                old_end.add_assign(&fragment_summary);
2061                if let Some(pending_edit) = pending_edit.as_mut() {
2062                    pending_edit.old.end = old_end.clone();
2063                } else {
2064                    pending_edit = Some(Edit {
2065                        old: self.old_end.clone()..old_end.clone(),
2066                        new: self.new_end.clone()..self.new_end.clone(),
2067                    });
2068                }
2069
2070                self.old_end = old_end;
2071            }
2072
2073            cursor.next(&None);
2074        }
2075
2076        pending_edit
2077    }
2078}
2079
2080impl Fragment {
2081    fn is_visible(&self, undos: &UndoMap) -> bool {
2082        !undos.is_undone(self.timestamp.local())
2083            && self.deletions.iter().all(|d| undos.is_undone(*d))
2084    }
2085
2086    fn was_visible(&self, version: &clock::Global, undos: &UndoMap) -> bool {
2087        (version.observed(self.timestamp.local())
2088            && !undos.was_undone(self.timestamp.local(), version))
2089            && self
2090                .deletions
2091                .iter()
2092                .all(|d| !version.observed(*d) || undos.was_undone(*d, version))
2093    }
2094}
2095
2096impl sum_tree::Item for Fragment {
2097    type Summary = FragmentSummary;
2098
2099    fn summary(&self) -> Self::Summary {
2100        let mut max_version = clock::Global::new();
2101        max_version.observe(self.timestamp.local());
2102        for deletion in &self.deletions {
2103            max_version.observe(*deletion);
2104        }
2105        max_version.join(&self.max_undos);
2106
2107        let mut min_insertion_version = clock::Global::new();
2108        min_insertion_version.observe(self.timestamp.local());
2109        let max_insertion_version = min_insertion_version.clone();
2110        if self.visible {
2111            FragmentSummary {
2112                text: FragmentTextSummary {
2113                    visible: self.len,
2114                    deleted: 0,
2115                },
2116                max_version,
2117                min_insertion_version,
2118                max_insertion_version,
2119            }
2120        } else {
2121            FragmentSummary {
2122                text: FragmentTextSummary {
2123                    visible: 0,
2124                    deleted: self.len,
2125                },
2126                max_version,
2127                min_insertion_version,
2128                max_insertion_version,
2129            }
2130        }
2131    }
2132}
2133
2134impl sum_tree::Summary for FragmentSummary {
2135    type Context = Option<clock::Global>;
2136
2137    fn add_summary(&mut self, other: &Self, _: &Self::Context) {
2138        self.text.visible += &other.text.visible;
2139        self.text.deleted += &other.text.deleted;
2140        self.max_version.join(&other.max_version);
2141        self.min_insertion_version
2142            .meet(&other.min_insertion_version);
2143        self.max_insertion_version
2144            .join(&other.max_insertion_version);
2145    }
2146}
2147
2148impl Default for FragmentSummary {
2149    fn default() -> Self {
2150        FragmentSummary {
2151            text: FragmentTextSummary::default(),
2152            max_version: clock::Global::new(),
2153            min_insertion_version: clock::Global::new(),
2154            max_insertion_version: clock::Global::new(),
2155        }
2156    }
2157}
2158
2159#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
2160pub struct FullOffset(usize);
2161
2162impl FullOffset {
2163    const MAX: Self = FullOffset(usize::MAX);
2164
2165    fn to_proto(self) -> u64 {
2166        self.0 as u64
2167    }
2168
2169    fn from_proto(value: u64) -> Self {
2170        Self(value as usize)
2171    }
2172}
2173
2174impl ops::AddAssign<usize> for FullOffset {
2175    fn add_assign(&mut self, rhs: usize) {
2176        self.0 += rhs;
2177    }
2178}
2179
2180impl ops::Add<usize> for FullOffset {
2181    type Output = Self;
2182
2183    fn add(mut self, rhs: usize) -> Self::Output {
2184        self += rhs;
2185        self
2186    }
2187}
2188
2189impl ops::Sub for FullOffset {
2190    type Output = usize;
2191
2192    fn sub(self, rhs: Self) -> Self::Output {
2193        self.0 - rhs.0
2194    }
2195}
2196
2197impl<'a> sum_tree::Dimension<'a, FragmentSummary> for usize {
2198    fn add_summary(&mut self, summary: &FragmentSummary, _: &Option<clock::Global>) {
2199        *self += summary.text.visible;
2200    }
2201}
2202
2203impl<'a> sum_tree::Dimension<'a, FragmentSummary> for FullOffset {
2204    fn add_summary(&mut self, summary: &FragmentSummary, _: &Option<clock::Global>) {
2205        self.0 += summary.text.visible + summary.text.deleted;
2206    }
2207}
2208
2209impl<'a> sum_tree::SeekTarget<'a, FragmentSummary, FragmentTextSummary> for usize {
2210    fn cmp(
2211        &self,
2212        cursor_location: &FragmentTextSummary,
2213        _: &Option<clock::Global>,
2214    ) -> cmp::Ordering {
2215        Ord::cmp(self, &cursor_location.visible)
2216    }
2217}
2218
2219#[derive(Copy, Clone, Debug, Eq, PartialEq)]
2220enum VersionedFullOffset {
2221    Offset(FullOffset),
2222    Invalid,
2223}
2224
2225impl VersionedFullOffset {
2226    fn full_offset(&self) -> FullOffset {
2227        if let Self::Offset(position) = self {
2228            *position
2229        } else {
2230            panic!("invalid version")
2231        }
2232    }
2233}
2234
2235impl Default for VersionedFullOffset {
2236    fn default() -> Self {
2237        Self::Offset(Default::default())
2238    }
2239}
2240
2241impl<'a> sum_tree::Dimension<'a, FragmentSummary> for VersionedFullOffset {
2242    fn add_summary(&mut self, summary: &'a FragmentSummary, cx: &Option<clock::Global>) {
2243        if let Self::Offset(offset) = self {
2244            let version = cx.as_ref().unwrap();
2245            if *version >= summary.max_insertion_version {
2246                *offset += summary.text.visible + summary.text.deleted;
2247            } else if !summary
2248                .min_insertion_version
2249                .iter()
2250                .all(|t| !version.observed(*t))
2251            {
2252                *self = Self::Invalid;
2253            }
2254        }
2255    }
2256}
2257
2258impl<'a> sum_tree::SeekTarget<'a, FragmentSummary, Self> for VersionedFullOffset {
2259    fn cmp(&self, cursor_position: &Self, _: &Option<clock::Global>) -> cmp::Ordering {
2260        match (self, cursor_position) {
2261            (Self::Offset(a), Self::Offset(b)) => Ord::cmp(a, b),
2262            (Self::Offset(_), Self::Invalid) => cmp::Ordering::Less,
2263            (Self::Invalid, _) => unreachable!(),
2264        }
2265    }
2266}
2267
2268impl Operation {
2269    fn replica_id(&self) -> ReplicaId {
2270        self.lamport_timestamp().replica_id
2271    }
2272
2273    fn lamport_timestamp(&self) -> clock::Lamport {
2274        match self {
2275            Operation::Edit(edit) => edit.timestamp.lamport(),
2276            Operation::Undo {
2277                lamport_timestamp, ..
2278            } => *lamport_timestamp,
2279            Operation::UpdateSelections {
2280                lamport_timestamp, ..
2281            } => *lamport_timestamp,
2282            Operation::RemoveSelections {
2283                lamport_timestamp, ..
2284            } => *lamport_timestamp,
2285            Operation::SetActiveSelections {
2286                lamport_timestamp, ..
2287            } => *lamport_timestamp,
2288            #[cfg(test)]
2289            Operation::Test(lamport_timestamp) => *lamport_timestamp,
2290        }
2291    }
2292
2293    pub fn is_edit(&self) -> bool {
2294        match self {
2295            Operation::Edit { .. } => true,
2296            _ => false,
2297        }
2298    }
2299}
2300
2301impl<'a> Into<proto::Operation> for &'a Operation {
2302    fn into(self) -> proto::Operation {
2303        proto::Operation {
2304            variant: Some(match self {
2305                Operation::Edit(edit) => proto::operation::Variant::Edit(edit.into()),
2306                Operation::Undo {
2307                    undo,
2308                    lamport_timestamp,
2309                } => proto::operation::Variant::Undo(proto::operation::Undo {
2310                    replica_id: undo.id.replica_id as u32,
2311                    local_timestamp: undo.id.value,
2312                    lamport_timestamp: lamport_timestamp.value,
2313                    ranges: undo
2314                        .ranges
2315                        .iter()
2316                        .map(|r| proto::Range {
2317                            start: r.start.to_proto(),
2318                            end: r.end.to_proto(),
2319                        })
2320                        .collect(),
2321                    counts: undo
2322                        .counts
2323                        .iter()
2324                        .map(|(edit_id, count)| proto::operation::UndoCount {
2325                            replica_id: edit_id.replica_id as u32,
2326                            local_timestamp: edit_id.value,
2327                            count: *count,
2328                        })
2329                        .collect(),
2330                    version: From::from(&undo.version),
2331                }),
2332                Operation::UpdateSelections {
2333                    set_id,
2334                    selections,
2335                    lamport_timestamp,
2336                } => proto::operation::Variant::UpdateSelections(
2337                    proto::operation::UpdateSelections {
2338                        replica_id: set_id.replica_id as u32,
2339                        local_timestamp: set_id.value,
2340                        lamport_timestamp: lamport_timestamp.value,
2341                        version: selections.version().into(),
2342                        selections: selections
2343                            .raw_entries()
2344                            .iter()
2345                            .map(|(range, state)| proto::Selection {
2346                                id: state.id as u64,
2347                                start: range.start.0.to_proto(),
2348                                end: range.end.0.to_proto(),
2349                                reversed: state.reversed,
2350                            })
2351                            .collect(),
2352                    },
2353                ),
2354                Operation::RemoveSelections {
2355                    set_id,
2356                    lamport_timestamp,
2357                } => proto::operation::Variant::RemoveSelections(
2358                    proto::operation::RemoveSelections {
2359                        replica_id: set_id.replica_id as u32,
2360                        local_timestamp: set_id.value,
2361                        lamport_timestamp: lamport_timestamp.value,
2362                    },
2363                ),
2364                Operation::SetActiveSelections {
2365                    set_id,
2366                    lamport_timestamp,
2367                } => proto::operation::Variant::SetActiveSelections(
2368                    proto::operation::SetActiveSelections {
2369                        replica_id: lamport_timestamp.replica_id as u32,
2370                        local_timestamp: set_id.map(|set_id| set_id.value),
2371                        lamport_timestamp: lamport_timestamp.value,
2372                    },
2373                ),
2374                #[cfg(test)]
2375                Operation::Test(_) => unimplemented!(),
2376            }),
2377        }
2378    }
2379}
2380
2381impl<'a> Into<proto::operation::Edit> for &'a EditOperation {
2382    fn into(self) -> proto::operation::Edit {
2383        let ranges = self
2384            .ranges
2385            .iter()
2386            .map(|range| proto::Range {
2387                start: range.start.to_proto(),
2388                end: range.end.to_proto(),
2389            })
2390            .collect();
2391        proto::operation::Edit {
2392            replica_id: self.timestamp.replica_id as u32,
2393            local_timestamp: self.timestamp.local,
2394            lamport_timestamp: self.timestamp.lamport,
2395            version: From::from(&self.version),
2396            ranges,
2397            new_text: self.new_text.clone(),
2398        }
2399    }
2400}
2401
2402impl TryFrom<proto::Operation> for Operation {
2403    type Error = anyhow::Error;
2404
2405    fn try_from(message: proto::Operation) -> Result<Self, Self::Error> {
2406        Ok(
2407            match message
2408                .variant
2409                .ok_or_else(|| anyhow!("missing operation variant"))?
2410            {
2411                proto::operation::Variant::Edit(edit) => Operation::Edit(edit.into()),
2412                proto::operation::Variant::Undo(undo) => Operation::Undo {
2413                    lamport_timestamp: clock::Lamport {
2414                        replica_id: undo.replica_id as ReplicaId,
2415                        value: undo.lamport_timestamp,
2416                    },
2417                    undo: UndoOperation {
2418                        id: clock::Local {
2419                            replica_id: undo.replica_id as ReplicaId,
2420                            value: undo.local_timestamp,
2421                        },
2422                        counts: undo
2423                            .counts
2424                            .into_iter()
2425                            .map(|c| {
2426                                (
2427                                    clock::Local {
2428                                        replica_id: c.replica_id as ReplicaId,
2429                                        value: c.local_timestamp,
2430                                    },
2431                                    c.count,
2432                                )
2433                            })
2434                            .collect(),
2435                        ranges: undo
2436                            .ranges
2437                            .into_iter()
2438                            .map(|r| FullOffset::from_proto(r.start)..FullOffset::from_proto(r.end))
2439                            .collect(),
2440                        version: undo.version.into(),
2441                    },
2442                },
2443                proto::operation::Variant::UpdateSelections(message) => {
2444                    let version = message.version.into();
2445                    let entries = message
2446                        .selections
2447                        .iter()
2448                        .map(|selection| {
2449                            let range = (FullOffset::from_proto(selection.start), Bias::Left)
2450                                ..(FullOffset::from_proto(selection.end), Bias::Right);
2451                            let state = SelectionState {
2452                                id: selection.id as usize,
2453                                reversed: selection.reversed,
2454                                goal: SelectionGoal::None,
2455                            };
2456                            (range, state)
2457                        })
2458                        .collect();
2459                    let selections = AnchorRangeMap::from_raw(version, entries);
2460
2461                    Operation::UpdateSelections {
2462                        set_id: clock::Lamport {
2463                            replica_id: message.replica_id as ReplicaId,
2464                            value: message.local_timestamp,
2465                        },
2466                        lamport_timestamp: clock::Lamport {
2467                            replica_id: message.replica_id as ReplicaId,
2468                            value: message.lamport_timestamp,
2469                        },
2470                        selections: Arc::from(selections),
2471                    }
2472                }
2473                proto::operation::Variant::RemoveSelections(message) => {
2474                    Operation::RemoveSelections {
2475                        set_id: clock::Lamport {
2476                            replica_id: message.replica_id as ReplicaId,
2477                            value: message.local_timestamp,
2478                        },
2479                        lamport_timestamp: clock::Lamport {
2480                            replica_id: message.replica_id as ReplicaId,
2481                            value: message.lamport_timestamp,
2482                        },
2483                    }
2484                }
2485                proto::operation::Variant::SetActiveSelections(message) => {
2486                    Operation::SetActiveSelections {
2487                        set_id: message.local_timestamp.map(|value| clock::Lamport {
2488                            replica_id: message.replica_id as ReplicaId,
2489                            value,
2490                        }),
2491                        lamport_timestamp: clock::Lamport {
2492                            replica_id: message.replica_id as ReplicaId,
2493                            value: message.lamport_timestamp,
2494                        },
2495                    }
2496                }
2497            },
2498        )
2499    }
2500}
2501
2502impl From<proto::operation::Edit> for EditOperation {
2503    fn from(edit: proto::operation::Edit) -> Self {
2504        let ranges = edit
2505            .ranges
2506            .into_iter()
2507            .map(|range| FullOffset::from_proto(range.start)..FullOffset::from_proto(range.end))
2508            .collect();
2509        EditOperation {
2510            timestamp: InsertionTimestamp {
2511                replica_id: edit.replica_id as ReplicaId,
2512                local: edit.local_timestamp,
2513                lamport: edit.lamport_timestamp,
2514            },
2515            version: edit.version.into(),
2516            ranges,
2517            new_text: edit.new_text,
2518        }
2519    }
2520}
2521
2522pub trait ToOffset {
2523    fn to_offset<'a>(&self, content: impl Into<Content<'a>>) -> usize;
2524
2525    fn to_full_offset<'a>(&self, content: impl Into<Content<'a>>, bias: Bias) -> FullOffset {
2526        let content = content.into();
2527        let offset = self.to_offset(&content);
2528        let mut cursor = content.fragments.cursor::<FragmentTextSummary>();
2529        cursor.seek(&offset, bias, &None);
2530        FullOffset(offset + cursor.start().deleted)
2531    }
2532}
2533
2534impl ToOffset for Point {
2535    fn to_offset<'a>(&self, content: impl Into<Content<'a>>) -> usize {
2536        content.into().visible_text.point_to_offset(*self)
2537    }
2538}
2539
2540impl ToOffset for PointUtf16 {
2541    fn to_offset<'a>(&self, content: impl Into<Content<'a>>) -> usize {
2542        content.into().visible_text.point_utf16_to_offset(*self)
2543    }
2544}
2545
2546impl ToOffset for usize {
2547    fn to_offset<'a>(&self, content: impl Into<Content<'a>>) -> usize {
2548        assert!(*self <= content.into().len(), "offset is out of range");
2549        *self
2550    }
2551}
2552
2553impl ToOffset for Anchor {
2554    fn to_offset<'a>(&self, content: impl Into<Content<'a>>) -> usize {
2555        content.into().summary_for_anchor(self).bytes
2556    }
2557}
2558
2559impl<'a> ToOffset for &'a Anchor {
2560    fn to_offset<'b>(&self, content: impl Into<Content<'b>>) -> usize {
2561        content.into().summary_for_anchor(self).bytes
2562    }
2563}
2564
2565pub trait ToPoint {
2566    fn to_point<'a>(&self, content: impl Into<Content<'a>>) -> Point;
2567}
2568
2569impl ToPoint for Anchor {
2570    fn to_point<'a>(&self, content: impl Into<Content<'a>>) -> Point {
2571        content.into().summary_for_anchor(self).lines
2572    }
2573}
2574
2575impl ToPoint for usize {
2576    fn to_point<'a>(&self, content: impl Into<Content<'a>>) -> Point {
2577        content.into().visible_text.offset_to_point(*self)
2578    }
2579}
2580
2581impl ToPoint for Point {
2582    fn to_point<'a>(&self, _: impl Into<Content<'a>>) -> Point {
2583        *self
2584    }
2585}
2586
2587pub trait FromAnchor {
2588    fn from_anchor<'a>(anchor: &Anchor, content: &Content<'a>) -> Self;
2589}
2590
2591impl FromAnchor for Point {
2592    fn from_anchor<'a>(anchor: &Anchor, content: &Content<'a>) -> Self {
2593        anchor.to_point(content)
2594    }
2595}
2596
2597impl FromAnchor for usize {
2598    fn from_anchor<'a>(anchor: &Anchor, content: &Content<'a>) -> Self {
2599        anchor.to_offset(content)
2600    }
2601}