Struct Cache

pub struct Cache<T> { /* private fields */ }

This is a lock-free concurrent cache. It stores only the most up-to-date value.

Implementations

impl<T> Cache<T>

pub fn new(value: T, version: usize) -> Self

pub fn value( &self, version: usize, f: impl FnOnce() -> T, ) -> Result<CacheValueType<T>, impl FnOnce() -> T>

Tries to retrieve value for the specified version. Returns a result either containing a cached value, or an f (which is guaranteed to be not invoked by function call in this case). If requested version corresponds to the value currently stored in cache - the value is returned. If requested version is older None will be returned. If requested version is newer, the new value will be computed and stored by calling f, and then returned, unless the value is being currently updated - in this case None will be returned. If None is returned it is guaranteed that f was not called.