referencecounted.h

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/*
Copyright (C) 2001-2006, William Joseph.
All Rights Reserved.

This file is part of GtkRadiant.

GtkRadiant is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

GtkRadiant 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#if !defined(INCLUDED_GENERIC_REFERENCECOUNTED_H)
#define INCLUDED_GENERIC_REFERENCECOUNTED_H


#include <algorithm>

template<typename Type>
class IncRefDecRefCounter {
public:
    void increment(Type& value) {
        value.IncRef();
    }
    void decrement(Type& value) {
        value.DecRef();
    }
};

template < typename Type, typename Counter = IncRefDecRefCounter<Type> >
class SmartPointer : public Counter {
    Type* m_value;
public:

    SmartPointer(const SmartPointer& other)
            : m_value(other.m_value) {
        Counter::increment(*m_value);
    }
    explicit SmartPointer(Type* value)
            : m_value(value) {
        Counter::increment(*m_value);
    }
    ~SmartPointer() {
        Counter::decrement(*m_value);
    }
    SmartPointer& operator=(const SmartPointer& other) {
        SmartPointer temp(other);
        temp.swap(*this);
        return *this;
    }
    SmartPointer& operator=(Type* value) {
        SmartPointer temp(value);
        temp.swap(*this);
        return *this;
    }
    void swap(SmartPointer& other) {
        std::swap(m_value, other.m_value);
    }

    operator Type*() const {
        return m_value;
    }
    Type& operator*() const {
        return *m_value;
    }
    Type* operator->() const {
        return m_value;
    }
    Type* get() const {
        return m_value;
    }
};

template<typename Type>
inline bool operator<(const SmartPointer<Type>& self, const SmartPointer<Type>& other) {
    return self.get() < other.get();
}
template<typename Type>
inline bool operator==(const SmartPointer<Type>& self, const SmartPointer<Type>& other) {
    return self.get() == other.get();
}
template<typename Type>
inline bool operator!=(const SmartPointer<Type>& self, const SmartPointer<Type>& other) {
    return !::operator==(self, other);
}

namespace std {
template<typename Type>
inline void swap(SmartPointer<Type>& self, SmartPointer<Type>& other) {
    self.swap(other);
}
}


template < typename Type, typename Counter = IncRefDecRefCounter<Type> >
class SmartReference : public Counter {
    Type* m_value;
public:

    SmartReference(const SmartReference& other)
            : m_value(other.m_value) {
        Counter::increment(*m_value);
    }
    explicit SmartReference(Type& value)
            : m_value(&value) {
        Counter::increment(*m_value);
    }
    ~SmartReference() {
        Counter::decrement(*m_value);
    }
    SmartReference& operator=(const SmartReference& other) {
        SmartReference temp(other);
        temp.swap(*this);
        return *this;
    }
    SmartReference& operator=(Type& value) {
        SmartReference temp(value);
        temp.swap(*this);
        return *this;
    }
    void swap(SmartReference& other) {
        std::swap(m_value, other.m_value);
    }

    operator Type&() const {
        return *m_value;
    }
    Type& get() const {
        return *m_value;
    }
    Type* get_pointer() const {
        return m_value;
    }
};

template<typename Type>
inline bool operator<(const SmartReference<Type>& self, const SmartReference<Type>& other) {
    return self.get() < other.get();
}
template<typename Type>
inline bool operator==(const SmartReference<Type>& self, const SmartReference<Type>& other) {
    return self.get() == other.get();
}
template<typename Type>
inline bool operator!=(const SmartReference<Type>& self, const SmartReference<Type>& other) {
    return !::operator==(self, other);
}

namespace std {
template<typename Type>
inline void swap(SmartReference<Type>& self, SmartReference<Type>& other) {
    self.swap(other);
}
}

#endif