icinga2/lib/base/shared.hpp

102 lines
1.7 KiB
C++

/* Icinga 2 | (c) 2019 Icinga GmbH | GPLv2+ */
#ifndef SHARED_H
#define SHARED_H
#include "base/atomic.hpp"
#include <boost/smart_ptr/intrusive_ptr.hpp>
#include <cstdint>
#include <utility>
namespace icinga
{
template<class T>
class Shared;
template<class T>
inline void intrusive_ptr_add_ref(Shared<T> *object)
{
object->m_References.fetch_add(1);
}
template<class T>
inline void intrusive_ptr_release(Shared<T> *object)
{
if (object->m_References.fetch_sub(1) == 1u) {
delete object;
}
}
/**
* Seemless wrapper for any class to create shared pointers of.
* Saves a memory allocation compared to std::shared_ptr.
*
* @ingroup base
*/
template<class T>
class Shared : public T
{
friend void intrusive_ptr_add_ref<>(Shared<T> *object);
friend void intrusive_ptr_release<>(Shared<T> *object);
public:
typedef boost::intrusive_ptr<Shared> Ptr;
/**
* Like std::make_shared, but for this class.
*
* @param args Constructor arguments
*
* @return Ptr
*/
template<class... Args>
static inline
Ptr Make(Args&&... args)
{
return new Shared(std::forward<Args>(args)...);
}
inline Shared(const Shared& origin) : Shared((const T&)origin)
{
}
inline Shared(Shared&& origin) : Shared((T&&)origin)
{
}
template<class... Args>
inline Shared(Args&&... args) : T(std::forward<Args>(args)...), m_References(0)
{
}
inline Shared& operator=(const Shared& rhs)
{
return operator=((const T&)rhs);
}
inline Shared& operator=(Shared&& rhs)
{
return operator=((T&&)rhs);
}
inline Shared& operator=(const T& rhs)
{
T::operator=(rhs);
return *this;
}
inline Shared& operator=(T&& rhs)
{
T::operator=(std::move(rhs));
return *this;
}
private:
Atomic<uint_fast64_t> m_References;
};
}
#endif /* SHARED_H */