cache::NWayLRU< T, U, Hash, Equal > Class Template Reference

Detailed Description

template<typename T, typename U, typename Hash = std::hash<T>, typename Equal = std::equal_to<T>>
class cache::NWayLRU< T, U, Hash, Equal >

Definition at line 20 of file nway_lru_cache.hpp.

Public Member Functions
	NWayLRU (size_t ways, size_t way_size, const Hash &hash=Hash(), const Equal &equal=Equal())
void	Put (const T &key, U value)
template<typename Validator >
std::optional< U >	Get (const T &key, Validator validator)
std::optional< U >	Get (const T &key)
U	GetOr (const T &key, const U &default_value)
void	Invalidate ()
void	InvalidateByKey (const T &key)
template<typename Function >
void	VisitAll (Function func) const
	Iterates over all items. May be slow for big caches.
size_t	GetSize () const
void	UpdateWaySize (size_t way_size)
void	Write (dump::Writer &writer) const
void	Read (dump::Reader &reader)
void	SetDumper (std::shared_ptr< dump::Dumper > dumper)

Constructor & Destructor Documentation

NWayLRU()

template<typename T , typename U , typename Hash = std::hash<T>, typename Equal = std::equal_to<T>>

cache::NWayLRU< T, U, Hash, Eq >::NWayLRU	(	size_t	ways,
		size_t	way_size,
		const Hash &	hash = Hash(),
		const Equal &	equal = Equal() )

Parameters

ways

is the number of ways (a.k.a. shards, internal hash-maps), into which elements are distributed based on their hash. Each shard is protected by an individual mutex. Larger ways means more internal hash-map instances and more memory usage, but less contention. A good starting point is ways=16. If you encounter contention, you can increase ways to something on the order of 256 or whatever your RAM constraints allow.

way_size

is the maximum allowed amount of elements per way. When the size of a way reaches this number, existing elements are deleted according to the LRU policy.

The maximum total number of elements is ways * way_size.

Definition at line 90 of file nway_lru_cache.hpp.

Member Function Documentation

Get() [1/2]

template<typename T , typename U , typename Hash = std::hash<T>, typename Equal = std::equal_to<T>>

std::optional< U > cache::NWayLRU< T, U, Hash, Equal >::Get ( const T & key )

inline

Definition at line 42 of file nway_lru_cache.hpp.

Get() [2/2]

template<typename T , typename U , typename Hash , typename Eq >

template<typename Validator >

std::optional< U > cache::NWayLRU< T, U, Hash, Eq >::Get	(	const T &	key,
		Validator	validator )

Definition at line 111 of file nway_lru_cache.hpp.

GetOr()

template<typename T , typename U , typename Hash , typename Eq >

U cache::NWayLRU< T, U, Hash, Eq >::GetOr	(	const T &	key,
		const U &	default_value )

Definition at line 135 of file nway_lru_cache.hpp.

GetSize()

template<typename T , typename U , typename Hash , typename Eq >

size_t cache::NWayLRU< T, U, Hash, Eq >::GetSize

(

)

const

Definition at line 160 of file nway_lru_cache.hpp.

Invalidate()

template<typename T , typename U , typename Hash , typename Eq >

void cache::NWayLRU< T, U, Hash, Eq >::Invalidate

(

)

Definition at line 142 of file nway_lru_cache.hpp.

InvalidateByKey()

template<typename T , typename U , typename Hash , typename Eq >

void cache::NWayLRU< T, U, Hash, Eq >::InvalidateByKey

(

const T &

key

)

Definition at line 125 of file nway_lru_cache.hpp.

Put()

template<typename T , typename U , typename Hash , typename Eq >

void cache::NWayLRU< T, U, Hash, Eq >::Put	(	const T &	key,
		U	value )

Definition at line 100 of file nway_lru_cache.hpp.

Read()

template<typename T , typename U , typename Hash , typename Equal >

void cache::NWayLRU< T, U, Hash, Equal >::Read

(

dump::Reader &

reader

)

Definition at line 206 of file nway_lru_cache.hpp.

SetDumper()

template<typename T , typename U , typename Hash , typename Equal >

void cache::NWayLRU< T, U, Hash, Equal >::SetDumper

(

std::shared_ptr< dump::Dumper >

dumper

)

The dump::Dumper will be notified of any cache updates. This method is not thread-safe.

Definition at line 228 of file nway_lru_cache.hpp.

UpdateWaySize()

template<typename T , typename U , typename Hash , typename Eq >

void cache::NWayLRU< T, U, Hash, Eq >::UpdateWaySize

(

size_t

way_size

)

For the description of way_size, see the cache::NWayLRU::NWayLRU constructor.

Definition at line 170 of file nway_lru_cache.hpp.

VisitAll()

template<typename T , typename U , typename Hash , typename Eq >

template<typename Function >

void cache::NWayLRU< T, U, Hash, Eq >::VisitAll

(

Function

func

)

const

Iterates over all items. May be slow for big caches.

Definition at line 152 of file nway_lru_cache.hpp.

Write()

template<typename T , typename U , typename Hash , typename Equal >

void cache::NWayLRU< T, U, Hash, Equal >::Write

(

dump::Writer &

writer

)

const

Definition at line 190 of file nway_lru_cache.hpp.

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The documentation for this class was generated from the following file:

• userver/cache/nway_lru_cache.hpp