pub struct TtlCache<K: Eq + Hash, V, S: BuildHasher = RandomState> { /* private fields */ }
Expand description
A time sensitive cache.
Implementations
sourceimpl<K: Eq + Hash, V, S: BuildHasher> TtlCache<K, V, S>
impl<K: Eq + Hash, V, S: BuildHasher> TtlCache<K, V, S>
sourcepub fn with_hasher(capacity: usize, hash_builder: S) -> Self
pub fn with_hasher(capacity: usize, hash_builder: S) -> Self
Creates an empty cache that can hold at most capacity
items
that expire after duration
with the given hash builder.
sourcepub fn contains_key<Q: ?Sized>(&self, key: &Q) -> boolwhere
K: Borrow<Q>,
Q: Hash + Eq,
pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> boolwhere
K: Borrow<Q>,
Q: Hash + Eq,
Check if the cache contains the given key.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(10);
cache.insert(1, "a", Duration::from_secs(30));
assert_eq!(cache.contains_key(&1), true);
sourcepub fn insert(&mut self, k: K, v: V, ttl: Duration) -> Option<V>
pub fn insert(&mut self, k: K, v: V, ttl: Duration) -> Option<V>
Inserts a key-value pair into the cache with an individual ttl for the key. If the key already existed and hasn’t expired, the old value is returned.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(2);
cache.insert(1, "a", Duration::from_secs(20));
cache.insert(2, "b", Duration::from_secs(60));
assert_eq!(cache.get(&1), Some(&"a"));
assert_eq!(cache.get(&2), Some(&"b"));
sourcepub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>where
K: Borrow<Q>,
Q: Hash + Eq,
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>where
K: Borrow<Q>,
Q: Hash + Eq,
Returns a reference to the value corresponding to the given key in the cache, if it contains an unexpired entry.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);
cache.insert(1, "a", duration);
cache.insert(2, "b", duration);
cache.insert(2, "c", duration);
cache.insert(3, "d", duration);
assert_eq!(cache.get(&1), None);
assert_eq!(cache.get(&2), Some(&"c"));
sourcepub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>where
K: Borrow<Q>,
Q: Hash + Eq,
pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>where
K: Borrow<Q>,
Q: Hash + Eq,
Returns a mutable reference to the value corresponding to the given key in the cache, if it contains an unexpired entry.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);
cache.insert(1, "a", duration);
cache.insert(2, "b", duration);
cache.insert(2, "c", duration);
cache.insert(3, "d", duration);
assert_eq!(cache.get_mut(&1), None);
assert_eq!(cache.get_mut(&2), Some(&mut "c"));
sourcepub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>where
K: Borrow<Q>,
Q: Hash + Eq,
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>where
K: Borrow<Q>,
Q: Hash + Eq,
Removes the given key from the cache and returns its corresponding value.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(2);
cache.insert(2, "a", Duration::from_secs(30));
assert_eq!(cache.remove(&1), None);
assert_eq!(cache.remove(&2), Some("a"));
assert_eq!(cache.remove(&2), None);
sourcepub fn capacity(&self) -> usize
pub fn capacity(&self) -> usize
Returns the maximum number of key-value pairs the cache can hold.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache: TtlCache<i32, &str> = TtlCache::new(2);
assert_eq!(cache.capacity(), 2);
sourcepub fn set_capacity(&mut self, capacity: usize)
pub fn set_capacity(&mut self, capacity: usize)
Sets the number of key-value pairs the cache can hold. Removes oldest key-value pairs if necessary.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);
cache.insert(1, "a", duration);
cache.insert(2, "b", duration);
cache.insert(3, "c", duration);
assert_eq!(cache.get(&1), None);
assert_eq!(cache.get(&2), Some(&"b"));
assert_eq!(cache.get(&3), Some(&"c"));
cache.set_capacity(3);
cache.insert(1, "a", duration);
cache.insert(2, "b", duration);
assert_eq!(cache.get(&1), Some(&"a"));
assert_eq!(cache.get(&2), Some(&"b"));
assert_eq!(cache.get(&3), Some(&"c"));
cache.set_capacity(1);
assert_eq!(cache.get(&1), None);
assert_eq!(cache.get(&2), Some(&"b"));
assert_eq!(cache.get(&3), None);
pub fn entry(&mut self, k: K) -> Entry<'_, K, V, S>
sourcepub fn iter(&mut self) -> Iter<'_, K, V>ⓘNotable traits for Iter<'a, K, V>impl<'a, K, V> Iterator for Iter<'a, K, V> type Item = (&'a K, &'a V);
pub fn iter(&mut self) -> Iter<'_, K, V>ⓘNotable traits for Iter<'a, K, V>impl<'a, K, V> Iterator for Iter<'a, K, V> type Item = (&'a K, &'a V);
Returns an iterator over the cache’s key-value pairs in oldest to youngest order.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);
cache.insert(1, 10, duration);
cache.insert(2, 20, duration);
cache.insert(3, 30, duration);
let kvs: Vec<_> = cache.iter().collect();
assert_eq!(kvs, [(&2, &20), (&3, &30)]);
sourcepub fn iter_mut(&mut self) -> IterMut<'_, K, V>ⓘNotable traits for IterMut<'a, K, V>impl<'a, K, V> Iterator for IterMut<'a, K, V> type Item = (&'a K, &'a mut V);
pub fn iter_mut(&mut self) -> IterMut<'_, K, V>ⓘNotable traits for IterMut<'a, K, V>impl<'a, K, V> Iterator for IterMut<'a, K, V> type Item = (&'a K, &'a mut V);
Returns an iterator over the cache’s key-value pairs in oldest to youngest order with mutable references to the values.
Examples
use std::time::Duration;
use ttl_cache::TtlCache;
let mut cache = TtlCache::new(2);
let duration = Duration::from_secs(30);
cache.insert(1, 10, duration);
cache.insert(2, 20, duration);
cache.insert(3, 30, duration);
let mut n = 2;
for (k, v) in cache.iter_mut() {
assert_eq!(*k, n);
assert_eq!(*v, n * 10);
*v *= 10;
n += 1;
}
assert_eq!(n, 4);
assert_eq!(cache.get(&2), Some(&200));
assert_eq!(cache.get(&3), Some(&300));