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c8dccd9905
More relaxed memory_order = less safety guarantees = faster execution. This is safe because std::shared_ptr does the same. See also: https://en.cppreference.com/w/cpp/atomic/memory_order "Typical use for relaxed memory ordering is incrementing counters, such as the reference counters of std::shared_ptr, since this only requires atomicity, but not ordering or synchronization (note that decrementing the std::shared_ptr counters requires acquire-release synchronization with the destructor)."
74 lines
1.3 KiB
C++
74 lines
1.3 KiB
C++
/* Icinga 2 | (c) 2019 Icinga GmbH | GPLv2+ */
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#ifndef SHARED_OBJECT_H
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#define SHARED_OBJECT_H
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#include "base/atomic.hpp"
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#include "base/object.hpp"
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#include <cstdint>
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namespace icinga
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{
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class SharedObject;
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inline void intrusive_ptr_add_ref(SharedObject *object);
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inline void intrusive_ptr_release(SharedObject *object);
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/**
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* Seamless and polymorphistic base for any class to create shared pointers of.
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* Saves a memory allocation compared to std::shared_ptr.
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*
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* @ingroup base
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*/
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class SharedObject
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{
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friend void intrusive_ptr_add_ref(SharedObject *object);
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friend void intrusive_ptr_release(SharedObject *object);
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protected:
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inline SharedObject() : m_References(0)
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{
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}
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inline SharedObject(const SharedObject&) : SharedObject()
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{
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}
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inline SharedObject(SharedObject&&) : SharedObject()
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{
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}
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inline SharedObject& operator=(const SharedObject&)
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{
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return *this;
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}
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inline SharedObject& operator=(SharedObject&&)
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{
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return *this;
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}
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inline virtual
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~SharedObject() = default;
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private:
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Atomic<uint_fast64_t> m_References;
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};
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inline void intrusive_ptr_add_ref(SharedObject *object)
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{
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object->m_References.fetch_add(1, std::memory_order_relaxed);
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}
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inline void intrusive_ptr_release(SharedObject *object)
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{
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if (object->m_References.fetch_sub(1, std::memory_order_acq_rel) == 1u) {
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delete object;
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}
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}
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}
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#endif /* SHARED_OBJECT_H */
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