Struct DynamicCacheLocal

pub struct DynamicCacheLocal<K, V, S = RandomState> { /* private fields */ }

A cache that will only hold onto items that have been requested more than once in recent memory. Single-use items are not held at all. Once an item is requested twice, it is cached until all memory of seeing a request has expired. The length of the memory is adjustable, and must be set at initialization.

Implementations

impl<K: Clone + Eq + Hash, V, S> DynamicCacheLocal<K, V, S>

pub fn with_hasher( mem_len: usize, hash_builder: S, ) -> DynamicCacheLocal<K, V, S>

Create and initialize a new cache, using the given hash builder to hash keys. The same warnings given for HashMap::with_hasher apply here.

impl<K: Clone + Eq + Hash, V> DynamicCacheLocal<K, V>

pub fn new(mem_len: usize) -> Self

Create and initialize a new cache.

pub fn get(&mut self, key: &K) -> Option<Arc<V>>

Attempt to retrieve a value from the cache. This updates the cache’s memory of what values have been requested.

pub fn pop(&mut self, key: &K) -> Option<Arc<V>>

Attempt to remove a value from the cache.

This will remove the value itself from the cache, but doesn’t change the cache’s stored request history. This means that any new [get_or_insert] calls will re-load the value into the cache.

pub fn insert(&mut self, key: &K, v: V) -> Arc<V>

Insert a value into the cache. If the value is already present, an Arc<V> of the stored value is returned. If the value is not stored but has been requested more than once, then it is stored and returned. If the value is not stored and hasn’t been requested more than once, it is not stored and is simply returned, wrapped as an Arc<V>.

pub fn get_or_insert<F: FnOnce() -> V>(&mut self, key: &K, f: F) -> Arc<V>

Fetch an item via the cache, potentially filling in the cache on a miss via the function f.

pub fn size(&self) -> usize

Get the number of items currently stored in the cache.

pub fn mem_len(&self) -> usize

Get the length of the cache’s recent request memory.

pub fn set_mem_len(&mut self, new_len: usize)

Change the length of the cache’s recent request memory. Some contents of the cache may be removed immediately if the new memory length is shorter than the old memory length.

pub fn clear_cache(&mut self)

Clear out all stored values and all memory in the cache.

pub fn hits(&self) -> u64

Get the number of hits this cache has seen.

pub fn misses(&self) -> u64

Get the number of misses this cache has seen.

pub fn reset_metrics(&mut self)

Reset the cache hit/miss metrics.

Trait Implementations

impl<K: Debug, V: Debug, S> Debug for DynamicCacheLocal<K, V, S>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.