weakPtr.h

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/*
 * i6engine
 * Copyright (2016) Daniel Bonrath, Michael Baer, All rights reserved.
 *
 * This file is part of i6engine; i6engine is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef __I6ENGINE_UTILS_WEAKPTR_H__
#define __I6ENGINE_UTILS_WEAKPTR_H__

#include "i6engine/utils/sharedPtr.h"

namespace i6e {
namespace utils {

        template<typename T, typename Base = T>
        class weakPtr {
        public:
                weakPtr() : _sharedPtrWrapper(std::make_shared<sharedPtrWrapper<Base>>(nullptr)), _ptr(nullptr) {
                }

                weakPtr(const weakPtr & other) : _sharedPtrWrapper(other._sharedPtrWrapper), _ptr(other._ptr) {
                }

                weakPtr(weakPtr && other) : _sharedPtrWrapper(other._sharedPtrWrapper), _ptr(other._ptr) {
                        other._sharedPtrWrapper.reset();
                        other._ptr = nullptr;
                }

                weakPtr(const sharedPtr<T, Base> & other) : _sharedPtrWrapper(other._sharedPtrWrapper), _ptr(other._ptr) {
                }

                template<typename U>
                weakPtr(const sharedPtr<U, T> & other) : _sharedPtrWrapper(other._sharedPtrWrapper), _ptr(other._ptr) {
                }

                template<typename U, typename V>
                weakPtr(const sharedPtr<U, V> & other) : _sharedPtrWrapper(other._sharedPtrWrapper), _ptr(other._ptr) {
                }

                ~weakPtr() {
                }

                const weakPtr & operator=(const weakPtr & other) {
                        if (*this == other) {
                                return *this;
                        }
                        _sharedPtrWrapper = other._sharedPtrWrapper;
                        _ptr = other._ptr;

                        return *this;
                }

                const weakPtr & operator=(weakPtr && other) {
                        if (*this == other) {
                                return *this;
                        }
                        _sharedPtrWrapper = other._sharedPtrWrapper;
                        _ptr = other._ptr;
                        other._sharedPtrWrapper.reset();
                        other._ptr = nullptr;

                        return *this;
                }

                bool operator==(const weakPtr & other) const {
                        return _ptr == other._ptr;
                }

                bool operator==(const T * other) const {
                        return _ptr == other;
                }

                bool operator!=(const weakPtr & other) const {
                        return !(*this == other);
                }

                bool operator!=(const T * other) const {
                        return !(*this == other);
                }

                bool operator<(const weakPtr & other) const {
                        return _ptr < other._ptr;
                }

                sharedPtr<T, Base> get() const {
                        auto p = _sharedPtrWrapper.lock();
                        return sharedPtr<T, Base>((p == nullptr) ? nullptr : _ptr, p);
                }

                bool expired() const {
                        return _sharedPtrWrapper.expired();
                }

        private:
                std::weak_ptr<sharedPtrWrapper<Base>> _sharedPtrWrapper;
                T * _ptr;
        };

} /* namespace utils */
} /* namespace i6e */

#endif /* __I6ENGINE_UTILS_WEAKPTR_H__ */