Struct FallbackCache

pub struct FallbackCache<Primary, Fallback> {
    primary: Primary,
    fallback: Fallback,
}

FallbackCache is a combinator for the ModuleCache trait that enables the chaining of two caching strategies together, typically via ModuleCache::with_fallback().

All operations are attempted using primary cache first, and if that fails, falls back to using the fallback cache. By chaining different caches together with FallbackCache, you can create a caching hierarchy tailored to your application’s specific needs, balancing performance, resource usage, and persistence.

A key assumption of FallbackCache is that all operations on the fallback implementation will be significantly slower than the primary one.

Cache Promotion

Whenever there is a cache miss on the primary cache and the fallback is able to load a module, that module is automatically added to the primary cache to improve the speed of future lookups.

This “cache promotion” strategy helps keep frequently accessed modules in the faster primary cache.

Fields

primary: Primary

fallback: Fallback

Implementations

impl<Primary, Fallback> FallbackCache<Primary, Fallback>

pub(crate) fn new(primary: Primary, fallback: Fallback) -> Self

pub fn primary(&self) -> &Primary

pub fn primary_mut(&mut self) -> &mut Primary

pub fn fallback(&self) -> &Fallback

pub fn fallback_mut(&mut self) -> &mut Fallback

pub fn into_inner(self) -> (Primary, Fallback)

Trait Implementations

impl<Primary: Clone, Fallback: Clone> Clone for FallbackCache<Primary, Fallback>

fn clone(&self) -> FallbackCache<Primary, Fallback>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<Primary: Debug, Fallback: Debug> Debug for FallbackCache<Primary, Fallback>

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

Formats the value using the given formatter.

impl<Primary: Hash, Fallback: Hash> Hash for FallbackCache<Primary, Fallback>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<Primary, Fallback> ModuleCache for FallbackCache<Primary, Fallback>

where Primary: ModuleCache + Send + Sync, Fallback: ModuleCache + Send + Sync,

fn load<'life0, 'life1, 'async_trait>( &'life0 self, key: ModuleHash, engine: &'life1 Engine, ) -> Pin<Box<dyn Future<Output = Result<Module, CacheError>> + Send + 'async_trait>>

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

Load a module based on its hash.

fn contains<'life0, 'life1, 'async_trait>( &'life0 self, key: ModuleHash, engine: &'life1 Engine, ) -> Pin<Box<dyn Future<Output = Result<bool, CacheError>> + Send + 'async_trait>>

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

Check if a module is present in the cache.

fn save<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, key: ModuleHash, engine: &'life1 Engine, module: &'life2 Module, ) -> Pin<Box<dyn Future<Output = Result<(), CacheError>> + Send + 'async_trait>>

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

Save a module so it can be retrieved with ModuleCache::load() at a later time.

fn with_fallback<C>(self, other: C) -> FallbackCache<Self, C>

where Self: Sized, C: ModuleCache,

Chain a second ModuleCache that will be used as a fallback if lookups on the primary cache fail.

impl<Primary: PartialEq, Fallback: PartialEq> PartialEq for FallbackCache<Primary, Fallback>

fn eq(&self, other: &FallbackCache<Primary, Fallback>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<Primary: Eq, Fallback: Eq> Eq for FallbackCache<Primary, Fallback>

impl<Primary, Fallback> StructuralPartialEq for FallbackCache<Primary, Fallback>