commandFunc.h

/* Copyright (c) 2006-2012, Stefan Eilemann <eile@equalizergraphics.com>
 *
 * This file is part of Collage <https://github.com/Eyescale/Collage>
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License version 2.1 as published
 * by the Free Software Foundation.
 *
 * 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 CO_COMMANDFUNC_H
#define CO_COMMANDFUNC_H

#include <co/types.h>
#include <lunchbox/debug.h>

// If you get a warning in your code, add this before in including this file:
//  #pragma warning( disable: 4407 )
// This warning is 'fixed' by https://github.com/Eyescale/Equalizer/issues/100

namespace co
{
template <typename T>
class CommandFunc
{
public:
    CommandFunc(T* object, bool (T::*func)(ICommand&))
        : _object(object)
        , _func(func)
    {
    }

    template <typename O>
    CommandFunc(const CommandFunc<O>& from)
        : _object(_convertThis<O>(from._object))
        , _func(static_cast<bool (T::*)(ICommand&)>(from._func))
    {
    }

    bool operator()(ICommand& command)
    {
        LBASSERT(_object);
        LBASSERT(_func);
        return (_object->*_func)(command);
    }

    void clear()
    {
        _object = 0;
        _func = 0;
    }
    bool isValid() const { return _object && _func; }
    // Can't make private because copy constructor needs access. Can't
    // declare friend because C++ does not allow generic template friends in
    // template classes.
    // private:
    T* _object;                  
    bool (T::*_func)(ICommand&); 


private:
    template <class F>
    T* _convertThis(F* ptr)
    {
#ifdef _MSC_VER
        // https://github.com/Eyescale/Equalizer/issues/100
        return reinterpret_cast<T*>(ptr);
#else
        return ptr;
#endif
    }
};

template <typename T>
inline std::ostream& operator<<(std::ostream& os, const CommandFunc<T>& func)
{
    if (func.isValid())
        os << "CommandFunc of " << lunchbox::className(func._object);
    else
        os << "NULL CommandFunc";
    return os;
}
}

#endif // CO_COMMANDFUNC_H