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590ad7a740
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)."
59 lines
1.3 KiB
C++
59 lines
1.3 KiB
C++
// SPDX-FileCopyrightText: 2019 Icinga GmbH <https://icinga.com>
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// SPDX-License-Identifier: GPL-2.0-or-later
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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(const SharedObject *object);
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inline void intrusive_ptr_release(const 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(const SharedObject *object);
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friend void intrusive_ptr_release(const 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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SharedObject(const SharedObject&) = delete;
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SharedObject& operator=(const SharedObject&) = delete;
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inline virtual
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~SharedObject() = default;
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private:
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mutable Atomic<uint_fast64_t> m_References;
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};
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inline void intrusive_ptr_add_ref(const 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(const 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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