micro_moka/unsync/
builder.rs

1use super::Cache;
2
3use std::{
4    collections::hash_map::RandomState,
5    hash::{BuildHasher, Hash},
6    marker::PhantomData,
7};
8
9/// Builds a [`Cache`][cache-struct] with various configuration knobs.
10///
11/// [cache-struct]: ./struct.Cache.html
12///
13/// # Examples
14///
15/// ```rust
16/// use micro_moka::unsync::Cache;
17///
18/// let mut cache = Cache::builder()
19///     // Max 10,000 elements
20///     .max_capacity(10_000)
21///     // Create the cache.
22///     .build();
23///
24/// cache.insert(0, "zero");
25/// cache.get(&0);
26/// ```
27///
28#[must_use]
29pub struct CacheBuilder<K, V, C> {
30    max_capacity: Option<u64>,
31    initial_capacity: Option<usize>,
32    cache_type: PhantomData<C>,
33    _marker: PhantomData<(K, V)>,
34}
35
36impl<K, V> Default for CacheBuilder<K, V, Cache<K, V, RandomState>>
37where
38    K: Eq + Hash,
39{
40    fn default() -> Self {
41        Self {
42            max_capacity: None,
43            initial_capacity: None,
44            cache_type: Default::default(),
45            _marker: Default::default(),
46        }
47    }
48}
49
50impl<K, V> CacheBuilder<K, V, Cache<K, V, RandomState>>
51where
52    K: Eq + Hash,
53{
54    /// Construct a new `CacheBuilder` that will be used to build a `Cache` holding
55    /// up to `max_capacity` entries.
56    pub fn new(max_capacity: u64) -> Self {
57        Self {
58            max_capacity: Some(max_capacity),
59            ..Default::default()
60        }
61    }
62
63    /// Builds a `Cache<K, V>`.
64    pub fn build(self) -> Cache<K, V, RandomState> {
65        let build_hasher = RandomState::default();
66        Cache::with_everything(self.max_capacity, self.initial_capacity, build_hasher)
67    }
68
69    /// Builds a `Cache<K, V, S>`, with the given `hasher`.
70    pub fn build_with_hasher<S>(self, hasher: S) -> Cache<K, V, S>
71    where
72        S: BuildHasher + Clone,
73    {
74        Cache::with_everything(self.max_capacity, self.initial_capacity, hasher)
75    }
76}
77
78impl<K, V, C> CacheBuilder<K, V, C> {
79    /// Sets the max capacity of the cache.
80    pub fn max_capacity(self, max_capacity: u64) -> Self {
81        Self {
82            max_capacity: Some(max_capacity),
83            ..self
84        }
85    }
86
87    /// Sets the initial capacity (number of entries) of the cache.
88    pub fn initial_capacity(self, number_of_entries: usize) -> Self {
89        Self {
90            initial_capacity: Some(number_of_entries),
91            ..self
92        }
93    }
94}
95
96#[cfg(test)]
97mod tests {
98    use super::CacheBuilder;
99
100    #[test]
101    fn build_cache() {
102        // Cache<char, String>
103        let mut cache = CacheBuilder::<char, String, _>::new(100).build();
104        let policy = cache.policy();
105
106        assert_eq!(policy.max_capacity(), Some(100));
107
108        cache.insert('a', "Alice".to_string());
109        assert_eq!(cache.get(&'a'), Some(&"Alice".to_string()));
110    }
111}
micro_moka/unsync/builder.rs

micro_moka/unsync/
builder.rs
