Struct dyn_cache::CacheMiss

pub struct CacheMiss<'k, Key: ?Sized, Scope, Input, Output, H = DefaultHashBuilder> { /* fields omitted */ }

The result of a failed attempt to retrieve a value from the cache. Initialize a full CacheEntry for storage with CacheMiss::init.

use dyn_cache::local::LocalCache;
let mut cache = LocalCache::default();
let (scope, arg) = (&'a', &1);

let miss = cache.get(scope, arg).expect_err("first access will always be a miss");

Implementations

impl<'k, Key: ?Sized, Scope, Input, Output, H> CacheMiss<'k, Key, Scope, Input, Output, H>

pub fn init<R>(
    self,
    query: impl FnOnce(&Input) -> (Output, R)
) -> (CacheEntry<'k, Key, Scope, Input, Output, H>, R)

Prepare the cache miss to be populated by running query(arg), returning a separate value. The value returned (R) is typically derived in some way from the stored Output.

let (entry, result): (_, Vec<usize>) = miss.init(|&n| {
    let v: Vec<usize> = vec![n; n];
    (v.clone(), v)
});
cache.store(entry);
assert_eq!(result, vec![1usize]);

Trait Implementations

impl<'k, Key: Clone + ?Sized, Scope: Clone, Input: Clone, Output: Clone, H: Clone> Clone for CacheMiss<'k, Key, Scope, Input, Output, H>

fn clone(&self) -> CacheMiss<'k, Key, Scope, Input, Output, H>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'k, Key: ?Sized, Scope, Input, Output, H> Debug for CacheMiss<'k, Key, Scope, Input, Output, H> where
    Key: Debug,
    Scope: Debug,
    Input: Debug, 

fn fmt(&self, f: &mut Formatter) -> FmtResult

Formats the value using the given formatter.

impl<'k, Key: Eq + ?Sized, Scope: Eq, Input: Eq, Output: Eq, H: Eq> Eq for CacheMiss<'k, Key, Scope, Input, Output, H>

impl<'k, Key: PartialEq + ?Sized, Scope: PartialEq, Input: PartialEq, Output: PartialEq, H: PartialEq> PartialEq<CacheMiss<'k, Key, Scope, Input, Output, H>> for CacheMiss<'k, Key, Scope, Input, Output, H>

fn eq(&self, other: &CacheMiss<'k, Key, Scope, Input, Output, H>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &CacheMiss<'k, Key, Scope, Input, Output, H>) -> bool

This method tests for !=.

impl<'k, Key: ?Sized, Scope, Input, Output, H> StructuralEq for CacheMiss<'k, Key, Scope, Input, Output, H>

impl<'k, Key: ?Sized, Scope, Input, Output, H> StructuralPartialEq for CacheMiss<'k, Key, Scope, Input, Output, H>