txmap 2.2.0

A concurrent transactional hash map for Rust with fine-grained locking, internal mutability and composable transactions
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

use crate::{
    key::TxKey,
    lock_guards::LockGuards,
    lock_policies::lock_policy::LockPolicy,
    new_types::BitMask,
    prepared::{ops::op_trait::OpTrait, schema::TxKeySelector},
};
use std::hash::Hash;

pub(crate) struct MoveValueOp<'tx, K, KEYS>
where
    K: Hash + Eq,
{
    pub key_selector_from: Box<dyn TxKeySelector<TxKey<K>, KEYS> + 'tx>,
    pub key_selector_to: Box<dyn TxKeySelector<TxKey<K>, KEYS> + 'tx>,
}

impl<'tx, K, V, L, KEYS, PARAMS, STATE> OpTrait<K, V, L, KEYS, PARAMS, STATE>
    for MoveValueOp<'tx, K, KEYS>
where
    K: Clone + Hash + Eq + 'tx,
    V: 'tx,
    L: LockPolicy + 'tx,
    KEYS: 'tx,
    PARAMS: 'tx,
    STATE: Default + 'tx,
{
    fn read_write_bitmasks(&self, keys: &KEYS) -> (BitMask, BitMask) {
        (
            BitMask::ZERO,
            self.key_selector_from.get(keys).shard_index.bitmask()
                | self.key_selector_to.get(keys).shard_index.bitmask(),
        )
    }
    fn apply(
        &self,
        lock_guards: &mut LockGuards<'_, K, V, L>,
        keys: &KEYS,
        _: &PARAMS,
        _: &mut STATE,
    ) {
        let key_from = self.key_selector_from.get(keys);
        let key_to = self.key_selector_to.get(keys);
        let removed = lock_guards.remove_entry(key_from);
        if let Some(entry) = removed {
            lock_guards.insert(key_to, entry.1);
        } else {
            lock_guards.remove_entry(key_to);
        }
    }
}