Struct cache::CacheHandle

pub struct CacheHandle<V>(/* private fields */);

A handle to a cache entry that might still be generating.

Implementations

impl<V: Any + Send + Sync> CacheHandle<V>

pub fn map<V2: Send + Sync + Any>( &self, map_fn: impl ValueMapFn<V, V2> ) -> CacheHandle<V2>

Maps an existing CacheHandle to a CacheHandle of a different type.

Example

use std::sync::{Arc, Mutex};
use cache::{mem::TypeCache, error::Error, CacheableWithState};

let mut cache = TypeCache::new();

fn generate_fn(tuple: &(u64, u64)) -> u64 {
    tuple.0 + tuple.1
}

let handle = cache.generate((5, 6), generate_fn);
assert_eq!(*handle.get(), 11);

// Does not call `generate_fn` again as the result has been cached.
let mapped_handle = handle.map(|res| res.map(|sum| *sum > 50));
assert_eq!(*mapped_handle.get(), false);

impl<V> CacheHandle<V>

pub fn try_get(&self) -> ArcResult<&V>

Blocks on the cache entry, returning the result once it is ready.

Returns an error if one was returned by the generator.

pub fn poll(&self) -> Option<ArcResult<&V>>

Checks whether the underlying entry is ready.

Returns the entry if available, otherwise returns None.

pub fn get(&self) -> &V

Blocks on the cache entry, returning its output.

Panics

Panics if the generator failed to run or an internal error was thrown by the cache.

impl<V: Debug> CacheHandle<V>

pub fn get_err(&self) -> Arc<Error>

Blocks on the cache entry, returning the error thrown by the cache.

Panics

Panics if no error was thrown by the cache.

impl<V, E> CacheHandle<Result<V, E>>

pub fn try_inner(&self) -> Result<&V, TryInnerError<'_, E>>

Blocks on the cache entry, returning the inner result.

Returns an error if the generator panicked or threw an error, or if the cache threw an error.

impl<V, E: Debug> CacheHandle<Result<V, E>>

pub fn unwrap_inner(&self) -> &V

Blocks on the cache entry, returning its output.

Panics

Panics if the generator panicked or threw an error, or if an internal error was thrown by the cache.

impl<V: Debug, E> CacheHandle<Result<V, E>>

pub fn unwrap_err_inner(&self) -> &E

Blocks on the cache entry, returning the error returned by the generator.

Panics

Panics if the generator panicked or an internal error was thrown by the cache. Also panics if the generator did not return an error.

Trait Implementations

impl<V> Clone for CacheHandle<V>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<V> Debug for CacheHandle<V>

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

Formats the value using the given formatter.