spk::CachedData< TType > Class Template Reference

Lazily generates and caches a value with optional custom destructor. More...

#include <spk_cached_data.hpp>

Collaboration diagram for spk::CachedData< TType >:

Public Types
using	value_type = TType
	Stored value type.
using	Generator = std::function<TType()>
	Callable used to lazily produce the cached value.
using	Destructor = std::function<void(TType &)>
	Optional cleanup function invoked when the cache is cleared.

Public Member Functions
	CachedData (Generator p_generator, Destructor p_destructor=nullptr)
	Builds a cache with a generator and optional destructor.
	~CachedData ()
	Destroys any cached value using the destructor callback if set.
	CachedData (const CachedData &)=delete
CachedData &	operator= (const CachedData &)=delete
	CachedData (CachedData &&p_other)=delete
CachedData &	operator= (CachedData &&p_other)=delete
TType &	get ()
	Retrieves the cached value, generating it on first access.
const TType &	get () const
	Retrieves the cached value, generating it on first access.
TType &	operator* ()
	Dereferences to the cached value, generating if needed.
const TType &	operator* () const
	Dereferences to the cached value, generating if needed.
TType *	operator-> ()
	Member access to the cached value, generating if needed.
const TType *	operator-> () const
	Member access to the cached value, generating if needed.
	operator TType & ()
	Implicitly converts to a mutable reference.
	operator const TType & () const
	Implicitly converts to a const reference.
void	release () const
	Releases the cached value by invoking destructor if provided.
void	configure (Generator p_generator, Destructor p_destructor=nullptr)
	Replaces the generator/destructor pair and clears any cached value.
void	set (const TType &p_value)
	Stores a value directly, bypassing the generator.
void	set (TType &&p_value)
	Stores a value directly, bypassing the generator (move overload).
std::optional< TType >	take ()
	Moves the cached value out of the cache without invoking the destructor.
bool	isCached () const
	Checks if a value is currently cached.
TType &	refresh ()
	Drops the cached value and regenerates it.

Detailed Description

template<typename TType>
class spk::CachedData< TType >

Lazily generates and caches a value with optional custom destructor.

Template Parameters

TType

cached value type (non-void).

spk::CachedData<std::string> blob([]{ return loadLarge(); });
auto &value = blob.get();
blob.release(); // free

Constructor & Destructor Documentation

CachedData()

template<typename TType>

spk::CachedData< TType >::CachedData ( Generator p_generator, Destructor p_destructor = nullptr )

inlineexplicit

Builds a cache with a generator and optional destructor.

Parameters

p_generator	Function to produce the value on demand.
p_destructor	Optional cleanup function for the value.

Member Function Documentation

configure()

template<typename TType>

void spk::CachedData< TType >::configure ( Generator p_generator, Destructor p_destructor = nullptr )

inline

Replaces the generator/destructor pair and clears any cached value.

Parameters

p_generator	New generator used to rebuild the value on demand.
p_destructor	Optional destructor for the cached value.

get() [1/2]

template<typename TType>

TType & spk::CachedData< TType >::get ( )

inline

Retrieves the cached value, generating it on first access.

Returns

Mutable reference to the cached value.

Here is the caller graph for this function:

get() [2/2]

template<typename TType>

const TType & spk::CachedData< TType >::get ( ) const

inline

Retrieves the cached value, generating it on first access.

Returns

Constant reference to the cached value.

isCached()

template<typename TType>

bool spk::CachedData< TType >::isCached ( ) const

inline

Checks if a value is currently cached.

Returns

true when data exists.

operator const TType &()

template<typename TType>

spk::CachedData< TType >::operator const TType & ( ) const

inline

Implicitly converts to a const reference.

Returns

Const reference to the value.

operator TType &()

template<typename TType>

spk::CachedData< TType >::operator TType & ( )

inline

Implicitly converts to a mutable reference.

Returns

Reference to the value.

operator*() [1/2]

template<typename TType>

TType & spk::CachedData< TType >::operator* ( )

inline

Dereferences to the cached value, generating if needed.

Returns

Mutable reference to the value.

operator*() [2/2]

template<typename TType>

const TType & spk::CachedData< TType >::operator* ( ) const

inline

Dereferences to the cached value, generating if needed.

Returns

Const reference to the value.

operator->() [1/2]

template<typename TType>

TType * spk::CachedData< TType >::operator-> ( )

inline

Member access to the cached value, generating if needed.

Returns

Pointer to the value.

operator->() [2/2]

template<typename TType>

const TType * spk::CachedData< TType >::operator-> ( ) const

inline

Member access to the cached value, generating if needed.

Returns

Const pointer to the value.

refresh()

template<typename TType>

TType & spk::CachedData< TType >::refresh ( )

inline

Drops the cached value and regenerates it.

Returns

Reference to the new value.

set() [1/2]

template<typename TType>

void spk::CachedData< TType >::set ( const TType & p_value )

inline

Stores a value directly, bypassing the generator.

Parameters

p_value

Value to cache.

set() [2/2]

template<typename TType>

void spk::CachedData< TType >::set ( TType && p_value )

inline

Stores a value directly, bypassing the generator (move overload).

Parameters

p_value

Value to cache.

take()

template<typename TType>

std::optional< TType > spk::CachedData< TType >::take ( )

inline

Moves the cached value out of the cache without invoking the destructor.

Returns

Optional containing the moved value if it was cached.

---

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

• includes/structure/design_pattern/spk_cached_data.hpp