// SPDX-FileCopyrightText: 2019 Icinga GmbH <https://icinga.com>
// SPDX-License-Identifier: GPL-2.0-or-later

#ifndef SHARED_OBJECT_H
#define SHARED_OBJECT_H

#include "base/atomic.hpp"
#include "base/object.hpp"
#include <cstdint>

namespace icinga
{

class SharedObject;

inline void intrusive_ptr_add_ref(const SharedObject *object);
inline void intrusive_ptr_release(const SharedObject *object);

/**
 * Seamless and polymorphistic base for any class to create shared pointers of.
 * Saves a memory allocation compared to std::shared_ptr.
 *
 * @ingroup base
 */
class SharedObject
{
	friend void intrusive_ptr_add_ref(const SharedObject *object);
	friend void intrusive_ptr_release(const SharedObject *object);

protected:
	inline SharedObject() : m_References(0)
	{
	}

	SharedObject(const SharedObject&) = delete;
	SharedObject& operator=(const SharedObject&) = delete;

	inline virtual
	~SharedObject() = default;

private:
	mutable Atomic<uint_fast64_t> m_References;
};

inline void intrusive_ptr_add_ref(const SharedObject *object)
{
	object->m_References.fetch_add(1);
}

inline void intrusive_ptr_release(const SharedObject *object)
{
	if (object->m_References.fetch_sub(1) == 1u) {
		delete object;
	}
}

}

#endif /* SHARED_OBJECT_H */
