pointer.h

/* This file is part of the KDE libraries
    Copyright (C) 2005, 2006 Ian Reinhart Geiser <[email protected]>
    Copyright (C) 2005, 2006 Matt Broadstone <[email protected]>
    Copyright (C) 2005, 2006 Richard J. Moore <[email protected]>
    Copyright (C) 2005, 2006 Erik L. Bunce <[email protected]>
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.
 
    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/
 
#ifndef POINTER_H
#define POINTER_H
 
#include <algorithm>
#include <typeinfo>
#include <QVariant>
 
namespace KJSEmbed
{
 
struct PointerBase {
public:
    virtual ~PointerBase()
    {
        ;
    }
    virtual void cleanup() = 0;
    virtual const std::type_info &type() const = 0;
    virtual void *voidStar() = 0;
};
 
template<typename ValueType>
struct Pointer : public PointerBase {
public:
    Pointer(ValueType *value) : ptr(value)
    {
//         qDebug("new pointer %s %0x", typeid(ValueType).name(), value);
    }
    ~Pointer() override
    {
 
    }
    void cleanup() override
    {
//         qDebug("delete pointer %s %0x", typeid(ValueType).name(), ptr );
        delete ptr;
        ptr = nullptr;
    }
    const std::type_info &type() const override
    {
        return typeid(ValueType);
    }
 
    void *voidStar() override
    {
        return (void *)ptr;
    }
 
    ValueType *ptr;
};
 
template<typename ValueType>
struct Value : public PointerBase {
public:
    Value(ValueType val) : value(val)
    {
        //qDebug("new value %s", typeid(ValueType).name());
    }
    ~Value() override
    {
        //qDebug("delete value");
    }
 
    void cleanup() override
    {
 
    }
 
    const std::type_info &type() const override
    {
        return typeid(ValueType);
    }
 
    void *voidStar() override
    {
        return (void *)&value;
    }
 
    ValueType value;
};
 
struct NullPtr : public PointerBase {
    NullPtr() : ptr(nullptr)
    {
        ;
    }
    ~NullPtr() override
    {
        ;
    }
    void cleanup() override
    {
        ;
    }
 
    const std::type_info &type() const override
    {
        return typeid(NullPtr);
    }
 
    void *voidStar() override
    {
        return &ptr;
    }
 
    void *ptr;
 
};
 
template<typename ValueType>
ValueType *pointer_cast(PointerBase *pointer)
{
//    qDebug("pointers %s %s", typeid(ValueType).name(), pointer->type().name() );
    if (typeid(ValueType) != pointer->type()) {
        return nullptr;
    }
    Pointer<ValueType> *upcast = static_cast< Pointer<ValueType> *>(pointer);
    return upcast->ptr;
}
 
}
 
Q_DECLARE_METATYPE(KJSEmbed::PointerBase *)
 
#endif