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
72
73
74
75
|
use core::hash::{BuildHasher, Hash};
use super::{Equivalent, IndexMap};
pub struct PrivateMarker {}
/// Opt-in mutable access to keys.
///
/// These methods expose `&mut K`, mutable references to the key as it is stored
/// in the map.
/// You are allowed to modify the keys in the hashmap **if the modification
/// does not change the key’s hash and equality**.
///
/// If keys are modified erroneously, you can no longer look them up.
/// This is sound (memory safe) but a logical error hazard (just like
/// implementing PartialEq, Eq, or Hash incorrectly would be).
///
/// `use` this trait to enable its methods for `IndexMap`.
pub trait MutableKeys {
type Key;
type Value;
/// Return item index, mutable reference to key and value
fn get_full_mut2<Q: ?Sized>(
&mut self,
key: &Q,
) -> Option<(usize, &mut Self::Key, &mut Self::Value)>
where
Q: Hash + Equivalent<Self::Key>;
/// Scan through each key-value pair in the map and keep those where the
/// closure `keep` returns `true`.
///
/// The elements are visited in order, and remaining elements keep their
/// order.
///
/// Computes in **O(n)** time (average).
fn retain2<F>(&mut self, keep: F)
where
F: FnMut(&mut Self::Key, &mut Self::Value) -> bool;
/// This method is not useful in itself – it is there to “seal” the trait
/// for external implementation, so that we can add methods without
/// causing breaking changes.
fn __private_marker(&self) -> PrivateMarker;
}
/// Opt-in mutable access to keys.
///
/// See [`MutableKeys`](trait.MutableKeys.html) for more information.
impl<K, V, S> MutableKeys for IndexMap<K, V, S>
where
K: Eq + Hash,
S: BuildHasher,
{
type Key = K;
type Value = V;
fn get_full_mut2<Q: ?Sized>(&mut self, key: &Q) -> Option<(usize, &mut K, &mut V)>
where
Q: Hash + Equivalent<K>,
{
self.get_full_mut2_impl(key)
}
fn retain2<F>(&mut self, keep: F)
where
F: FnMut(&mut K, &mut V) -> bool,
{
self.retain_mut(keep)
}
fn __private_marker(&self) -> PrivateMarker {
PrivateMarker {}
}
}
|
