txmap 2.2.2

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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71

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

pub(crate) struct RemoveIfOp<'tx, K, V, KEYS, PARAMS, STATE>
where
    K: Hash + Eq,
{
    pub key_selector: Box<dyn TxKeySelector<TxKey<K>, KEYS> + 'tx>,
    #[allow(clippy::type_complexity)]
    pub condition: Box<dyn Fn(&K, &V, &PARAMS, &mut STATE) -> bool + 'tx>,
}

impl<'tx, K, V, L, KEYS, PARAMS, STATE> OpTrait<K, V, L, KEYS, PARAMS, STATE>
    for RemoveIfOp<'tx, K, V, KEYS, PARAMS, STATE>
where
    K: 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.get(keys).shard_index.bitmask(),
        )
    }
    fn apply(
        &self,
        lock_guards: &mut LockGuards<'_, K, V, L>,
        keys: &KEYS,
        params: &PARAMS,
        state: &mut STATE,
    ) {
        let key = self.key_selector.get(keys);

        if (key.shard_index.bitmask() & lock_guards.write_bitmask) != BitMask::ZERO {
            let value_ref = lock_guards
                .write
                .get(key.shard_index.0)
                .expect(MISSING_LOCK_GUARD_ERROR)
                .find(key.hash_code.0, |entry| entry.0 == key.key)
                .map(|(_key, value)| value);
            if let Some(v) = value_ref
                && (self.condition)(&key.key, v, params, state)
            {
                lock_guards.remove_entry(key);
            }
        } else {
            let value_ref = lock_guards
                .read
                .get(key.shard_index.0)
                .expect(MISSING_LOCK_GUARD_ERROR)
                .find(key.hash_code.0, |entry| entry.0 == key.key)
                .map(|(_key, value)| value);
            if let Some(v) = value_ref
                && (self.condition)(&key.key, v, params, state)
            {
                lock_guards.remove_entry(key);
            }
        }
    }
}