log/kv/
key.rs

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1//! Structured keys.
2
3use std::borrow::Borrow;
4use std::fmt;
5
6/// A type that can be converted into a [`Key`](struct.Key.html).
7pub trait ToKey {
8    /// Perform the conversion.
9    fn to_key(&self) -> Key;
10}
11
12impl<'a, T> ToKey for &'a T
13where
14    T: ToKey + ?Sized,
15{
16    fn to_key(&self) -> Key {
17        (**self).to_key()
18    }
19}
20
21impl<'k> ToKey for Key<'k> {
22    fn to_key(&self) -> Key {
23        Key { key: self.key }
24    }
25}
26
27impl ToKey for str {
28    fn to_key(&self) -> Key {
29        Key::from_str(self)
30    }
31}
32
33/// A key in a key-value.
34// These impls must only be based on the as_str() representation of the key
35// If a new field (such as an optional index) is added to the key they must not affect comparison
36#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
37pub struct Key<'k> {
38    key: &'k str,
39}
40
41impl<'k> Key<'k> {
42    /// Get a key from a borrowed string.
43    pub fn from_str(key: &'k str) -> Self {
44        Key { key }
45    }
46
47    /// Get a borrowed string from this key.
48    pub fn as_str(&self) -> &str {
49        self.key
50    }
51}
52
53impl<'k> fmt::Display for Key<'k> {
54    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
55        self.key.fmt(f)
56    }
57}
58
59impl<'k> AsRef<str> for Key<'k> {
60    fn as_ref(&self) -> &str {
61        self.as_str()
62    }
63}
64
65impl<'k> Borrow<str> for Key<'k> {
66    fn borrow(&self) -> &str {
67        self.as_str()
68    }
69}
70
71impl<'k> From<&'k str> for Key<'k> {
72    fn from(s: &'k str) -> Self {
73        Key::from_str(s)
74    }
75}
76
77#[cfg(feature = "std")]
78mod std_support {
79    use super::*;
80
81    use std::borrow::Cow;
82
83    impl ToKey for String {
84        fn to_key(&self) -> Key {
85            Key::from_str(self)
86        }
87    }
88
89    impl<'a> ToKey for Cow<'a, str> {
90        fn to_key(&self) -> Key {
91            Key::from_str(self)
92        }
93    }
94}
95
96#[cfg(feature = "kv_sval")]
97mod sval_support {
98    use super::*;
99
100    use sval::Value;
101    use sval_ref::ValueRef;
102
103    impl<'a> Value for Key<'a> {
104        fn stream<'sval, S: sval::Stream<'sval> + ?Sized>(
105            &'sval self,
106            stream: &mut S,
107        ) -> sval::Result {
108            self.key.stream(stream)
109        }
110    }
111
112    impl<'a> ValueRef<'a> for Key<'a> {
113        fn stream_ref<S: sval::Stream<'a> + ?Sized>(&self, stream: &mut S) -> sval::Result {
114            self.key.stream(stream)
115        }
116    }
117}
118
119#[cfg(feature = "kv_serde")]
120mod serde_support {
121    use super::*;
122
123    use serde::{Serialize, Serializer};
124
125    impl<'a> Serialize for Key<'a> {
126        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
127        where
128            S: Serializer,
129        {
130            self.key.serialize(serializer)
131        }
132    }
133}
134
135#[cfg(test)]
136mod tests {
137    use super::*;
138
139    #[test]
140    fn key_from_string() {
141        assert_eq!("a key", Key::from_str("a key").as_str());
142    }
143}
log/kv/key.rs

log/kv/
key.rs
