Diligent::LRUCache< KeyType, DataType, KeyHasher > Class Template Reference

A thread-safe and exception-safe LRU cache. More...

#include <LRUCache.hpp>

Public Member Functions
template<typename InitDataType>
DataType	Get (const KeyType &Key, InitDataType &&InitData) noexcept(false)
void	SetMaxSize (size_t MaxSize)
	Sets the maximum cache size.
size_t	GetCurrSize () const
	Returns the current cache size.

Detailed Description

template<typename KeyType, typename DataType, typename KeyHasher = std::hash<KeyType>>
class Diligent::LRUCache< KeyType, DataType, KeyHasher >

A thread-safe and exception-safe LRU cache.

Usage example:

struct CacheData
{
    RefCntAutoPtr<IDataBlob> pData;
};
LRUCache<std::string, CacheData> Cache;
Cache.SetMaxSize(32768);
auto Data = Cache.Get("DataKey",
                      [](CacheData& Data, size_t& Size) //
                      {
                          // Create the data and return its size.
                          // May throw an exception in case of an error.
                          Data.pData = pData;
                          Size       = pData->GetSize();
                      });

The Get() method returns the data by value, as the copy kept by the cache may be released immediately after the method finishes.

If the data is not found, it is atomically initialized by the provided initializer function. If the data is found, the initializer function is not called.

Member Function Documentation

Get()

template<typename KeyType, typename DataType, typename KeyHasher = std::hash<KeyType>>

template<typename InitDataType>

DataType Diligent::LRUCache< KeyType, DataType, KeyHasher >::Get ( const KeyType & Key, InitDataType && InitData )

inline

Finds the data in the cache and returns it. If the data is not found, it is atomically created using the provided initializer.

Parameters

[in]	Key	- The data key.
[in]	InitData	- Initializer function that is called if the data is not found in the cache.

Returns

Data with the specified key, either retrieved from the cache or initialized with the InitData function.

Remarks

InitData function may throw in case of an error.