1use super::Operation;
  2use std::{fmt::Debug, ops::Add};
  3use sum_tree::{Cursor, Dimension, Edit, Item, KeyedItem, SumTree, Summary};
  4
  5#[derive(Clone, Debug)]
  6pub struct OperationQueue(SumTree<Operation>);
  7
  8#[derive(Clone, Copy, Debug, Default, Eq, Ord, PartialEq, PartialOrd)]
  9pub struct OperationKey(clock::Lamport);
 10
 11#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
 12pub struct OperationSummary {
 13    pub key: OperationKey,
 14    pub len: usize,
 15}
 16
 17impl OperationKey {
 18    pub fn new(timestamp: clock::Lamport) -> Self {
 19        Self(timestamp)
 20    }
 21}
 22
 23impl OperationQueue {
 24    pub fn new() -> Self {
 25        OperationQueue(SumTree::new())
 26    }
 27
 28    pub fn len(&self) -> usize {
 29        self.0.summary().len
 30    }
 31
 32    pub fn insert(&mut self, mut ops: Vec<Operation>) {
 33        ops.sort_by_key(|op| op.lamport_timestamp());
 34        ops.dedup_by_key(|op| op.lamport_timestamp());
 35        self.0
 36            .edit(ops.into_iter().map(Edit::Insert).collect(), &());
 37    }
 38
 39    pub fn drain(&mut self) -> Self {
 40        let clone = self.clone();
 41        self.0 = SumTree::new();
 42        clone
 43    }
 44
 45    pub fn cursor(&self) -> Cursor<Operation, ()> {
 46        self.0.cursor()
 47    }
 48}
 49
 50impl Summary for OperationSummary {
 51    type Context = ();
 52
 53    fn add_summary(&mut self, other: &Self, _: &()) {
 54        assert!(self.key < other.key);
 55        self.key = other.key;
 56        self.len += other.len;
 57    }
 58}
 59
 60impl<'a> Add<&'a Self> for OperationSummary {
 61    type Output = Self;
 62
 63    fn add(self, other: &Self) -> Self {
 64        assert!(self.key < other.key);
 65        OperationSummary {
 66            key: other.key,
 67            len: self.len + other.len,
 68        }
 69    }
 70}
 71
 72impl<'a> Dimension<'a, OperationSummary> for OperationKey {
 73    fn add_summary(&mut self, summary: &OperationSummary, _: &()) {
 74        assert!(*self <= summary.key);
 75        *self = summary.key;
 76    }
 77}
 78
 79impl Item for Operation {
 80    type Summary = OperationSummary;
 81
 82    fn summary(&self) -> Self::Summary {
 83        OperationSummary {
 84            key: OperationKey::new(self.lamport_timestamp()),
 85            len: 1,
 86        }
 87    }
 88}
 89
 90impl KeyedItem for Operation {
 91    type Key = OperationKey;
 92
 93    fn key(&self) -> Self::Key {
 94        OperationKey::new(self.lamport_timestamp())
 95    }
 96}
 97
 98#[cfg(test)]
 99mod tests {
100    use super::*;
101
102    #[test]
103    fn test_len() {
104        let mut clock = clock::Lamport::new(0);
105
106        let mut queue = OperationQueue::new();
107        assert_eq!(queue.len(), 0);
108
109        queue.insert(vec![
110            Operation::Test(clock.tick()),
111            Operation::Test(clock.tick()),
112        ]);
113        assert_eq!(queue.len(), 2);
114
115        queue.insert(vec![Operation::Test(clock.tick())]);
116        assert_eq!(queue.len(), 3);
117
118        drop(queue.drain());
119        assert_eq!(queue.len(), 0);
120
121        queue.insert(vec![Operation::Test(clock.tick())]);
122        assert_eq!(queue.len(), 1);
123    }
124
125    #[derive(Clone, Debug, Eq, PartialEq)]
126    struct TestOperation(clock::Lamport);
127}