Struct Cache

pub struct Cache { /* private fields */ }

Implementations

impl Cache

pub fn drop()

Drops the global cache instance and clears all in-memory entries, locks, and file locks.

After calling this, Cache::instance will return an error until Cache::new is called again.

pub fn instance() -> Result<Self, Box<dyn Error>>

Returns the globally initialized Cache instance if it exists.

Errors

Returns an error if Cache::new has not been called yet.

Example

let cache = cache_ro::Cache::instance().unwrap();

pub fn new(config: CacheConfig) -> Result<Self, Box<dyn Error>>

Creates and initializes a new global Cache instance.

If persistence is enabled in the provided CacheConfig, the directory will be created and any persisted entries will be loaded into memory.

This will also start a background thread to periodically clean up expired entries.

Errors

Returns an error if:

• A cache instance already exists.
• The persistence directory cannot be created.

Example

let cache = cache_ro::Cache::new(Default::default()).unwrap();

pub fn set<V: Serialize>( &self, key: &str, value: V, ttl: Duration, ) -> Result<(), Box<dyn Error>>

Stores a value in the cache with a specified TTL (time-to-live).

If persistence is enabled, the value will also be saved to disk.

Arguments

• key - Cache key.
• value - Serializable value to store.
• ttl - Expiration duration.

Errors

Returns an error if serialization or persistence fails.

pub fn get<V: for<'de> Deserialize<'de>>(&self, key: &str) -> Option<V>

Retrieves and deserializes a value from the cache if it has not expired.

Type Parameters

• V - Type to deserialize into.

Arguments

• key - Cache key.

Returns

Some(value) if the entry exists and is valid, otherwise None.

pub fn expire(&self, key: &str) -> Option<Duration>

Returns the remaining TTL for a given cache key.

Returns

Some(duration) if the entry exists and is not expired, otherwise None.

pub fn remove(&self, key: &str) -> Result<(), Box<dyn Error>>

Removes an entry from the cache.

If persistence is enabled, the removal is also reflected on disk.

Errors

Returns an error if persistence fails.

pub fn clear(&self) -> Result<(), Box<dyn Error>>

Clears all entries from the cache (in memory and on disk if persistent).

Errors

Returns an error if persistent files cannot be deleted.

pub fn len(&self) -> usize

Returns the number of entries currently stored in memory.

pub fn is_empty(&self) -> bool

Checks whether the cache contains no entries.

pub fn memory_usage(&self) -> usize

Trait Implementations

impl Clone for Cache

fn clone(&self) -> Cache

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.