lru-cache-map

A cache that holds a limited number of key-value pairs.

This is a mirror of mozilla/sccache/lru-cache, which is derived from contain-rs/lru-cache.

lib.rs:

A cache that holds a limited number of key-value pairs. When the capacity of the cache is exceeded, the least-recently-used (where "used" means a look-up or putting the pair into the cache) pair is automatically removed.

Examples

#
let mut cache = LruCache::new(2);

cache.insert(1, 10);
cache.insert(2, 20);
cache.insert(3, 30);
assert!(cache.get_mut(&1).is_none());
assert_eq!(*cache.get_mut(&2).unwrap(), 20);
assert_eq!(*cache.get_mut(&3).unwrap(), 30);

cache.insert(2, 22);
assert_eq!(*cache.get_mut(&2).unwrap(), 22);

cache.insert(6, 60);
assert!(cache.get_mut(&3).is_none());

cache.set_capacity(1);
assert!(cache.get_mut(&2).is_none());

The cache can also be limited by an arbitrary metric calculated from its key-value pairs, see LruCache::with_meter for more information. Custom metrics can be written by implementing the Meter trait.