object.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef GRIM_OBJECT_H
#define GRIM_OBJECT_H

#include "common/list.h"

namespace Grim {

class SaveGame;

class Pointer;
class Object {
public:
    Object();
    virtual ~Object();

    void reset() { };
    void reference();
    void dereference();

    int32 getId() const;

private:
    void setId(int32 id);
    int _refCount;
    Common::List<Pointer *> _pointers;
    int32 _id;
    static int32 s_id;

    friend class Pointer;
};

class Pointer {
protected:
    virtual ~Pointer() {}

    void addPointer(Object *obj) {
        obj->_pointers.push_back(this);
    }
    void rmPointer(Object *obj) {
        obj->_pointers.remove(this);
    }

    virtual void resetPointer() {}

    friend class Object;
};

template<class T> class ObjectPtr : public Pointer {
public:
    ObjectPtr() :
        _obj(nullptr) {

    }
    ObjectPtr(T *obj) :
        _obj(obj) {
        if (obj) {
            Object *o = (Object *)_obj;
            o->reference();
            addPointer(o);
        }
    }
    ObjectPtr(const ObjectPtr<T> &ptr) : Pointer() {
        _obj = nullptr;
        *this = ptr;
    }
    ~ObjectPtr() {
        if (_obj) {
            Object *o = (Object *)_obj;
            rmPointer(o);
            o->dereference();
        }
    }

    ObjectPtr &operator=(T *obj) {
        if (obj != _obj) {
            if (_obj) {
                rmPointer(_obj);
                _obj->dereference();
                _obj = nullptr;

            }

            if (obj) {
                _obj = obj;
                _obj->reference();
                addPointer(obj);
            }
        }

        return *this;
    }
    ObjectPtr &operator=(const ObjectPtr<T> &ptr) {
        if (_obj != ptr._obj) {
            if (_obj) {
                rmPointer(_obj);
                _obj->dereference();
                _obj = nullptr;

            }

            if (ptr._obj) {
                _obj = ptr._obj;
                _obj->reference();
                addPointer(_obj);
            }
        }

        return *this;
    }
    bool operator==(const ObjectPtr &ptr) const {
        return (_obj == ptr._obj);
    }
    bool operator==(Object *obj) const {
        return (_obj == obj);
    }
    operator bool() const {
        return (_obj);
    }
    bool operator!() const {
        return (!_obj);
    }

    T *object() const {
        return _obj;
    }
    T *operator->() const {
        return _obj;
    }
    T &operator*() const {
        return *_obj;
    }
    operator T*() const {
        return _obj;
    }

protected:
    void resetPointer() override {
        _obj = nullptr;
    }

private:
    T *_obj;
};

}

#endif