Struct Cache 

pub struct Cache { /* private fields */ }

A write-through cache in front of a backing Storage.

Reads consult the in-memory LRU first and fall back to the backend on a miss (populating the cache). Writes update both the cache and the backend so the cache never serves stale data for keys it owns.

Implementations

impl Cache

pub fn new(inner: Arc<dyn Storage>, capacity: usize) -> Self

Wrap inner with an LRU cache of the given capacity.

A capacity of 0 is treated as 1 (LRU requires non-zero capacity).

pub fn len(&self) -> usize

Number of entries currently cached.

pub fn is_empty(&self) -> bool

Whether the cache holds no entries.

Trait Implementations

impl Storage for Cache

fn save<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, key: &'life1 str, value: &'life2 Value, ) -> Pin<Box<dyn Future<Output = StorageResult<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait,

Persist value under key, overwriting any existing entry.

fn load<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = StorageResult<Option<Value>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Load the value stored under key, or None if absent.

fn delete<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = StorageResult<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Remove key. Removing a missing key is a no-op (not an error).

fn list<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = StorageResult<Vec<String>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

List all keys currently present.