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#if !defined(GUICALLBACK_H)
#define GUICALLBACK_H
/*
* Copyright (C) 2005-2008 Team XBMC
* http://www.xbmc.org
*
* 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 2, 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 XBMC; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
* http://www.gnu.org/copyleft/gpl.html
*
*/
#include "assert.h"
#include "memory.h"
#ifndef __GNUC__
#pragma warning( disable : 4786 )
#endif
////////////////////////////////////////////////////////////////////////////////////////////////
// NOTE FROM RUNTiME: An Event holds a weak reference to class method, it acts similar to a //
// C# delegate method E.g. instantiate an Event and assign it an EventHandler, whenever the //
// Event is fired the EventHandler is executed. //
// - There is a 2nd variant of Event called a Callback, this only differs in that a Callback //
// can return a value after the CallbackHandler has been executed. //
// - There is a nasty memcpy that gets us over the compiler restriction that prevents us from //
// casting between two different method pointers, not the cleanest solution granted, but it's //
// the only way I know how to get around this limitation. //
////////////////////////////////////////////////////////////////////////////////////////////////
template <class Cookie>
class GUIEvent
{
public:
typedef void (GUIEvent::*MethodPtr)(Cookie);
GUIEvent()
{
m_pInstance = NULL;
m_pMethod = NULL;
}
// Assign an EventHandler (EventHandler's are derived from Event)
GUIEvent<Cookie> &operator=(GUIEvent<Cookie> &aEvent)
{
if (&aEvent)
{
m_pInstance = aEvent.m_pInstance;
m_pMethod = aEvent.m_pMethod;
}
else
{
GUIEvent();
}
return *this;
}
// Are the class instance and method pointers initialised?
bool HasAHandler()
{
return (m_pInstance && m_pMethod);
}
// Execute the associated class method
void Fire(Cookie aCookie)
{
if (HasAHandler())
{
(m_pInstance->*m_pMethod)(aCookie);
}
else
{
// Event is uninitialized, no handler has been assigned
assert(0);
}
}
MethodPtr m_pMethod;
protected:
GUIEvent* m_pInstance;
};
template <class Class, class Cookie>
class GUIEventHandler : public GUIEvent<Cookie>
{
public:
typedef void (Class::*MethodPtr)(Cookie);
GUIEventHandler(Class* pInstance, MethodPtr aMethodPtr)
{
GUIEvent<Cookie>::m_pInstance = (GUIEvent<Cookie>*) ((LPVOID) pInstance);
#ifndef _LINUX
// Its dirty but it works!
memcpy(&m_pMethod, &aMethodPtr, sizeof(GUIEvent<Cookie>::m_pMethod));
#else
// Well, GCC doesn't like that dirty stuff... here's another version of the same thing
// but even dirtier *grin*
#define my_offsetof(TYPE, MEMBER) \
((size_t)((char *)&(((TYPE *)0x10)->MEMBER) - (char*)0x10))
void* target = (void*) (((char*) this) + my_offsetof(GUIEvent<Cookie>, m_pMethod));
memcpy(target, &aMethodPtr, sizeof(GUIEvent<Cookie>::m_pMethod));
#endif
}
};
// Callbacks are identical to Events except that a Callback returns a result value
template <class Result, class Cookie>
class Callback
{
public:
typedef Result (Callback::*MethodPtr)(Cookie);
Callback()
{
m_pInstance = NULL;
m_pMethod = NULL;
}
// Assign a CallbackHandler (CallbackHandler's are derived from Callback)
Callback<Result, Cookie> &operator=(Callback<Result, Cookie> &aCallback)
{
if (&aCallback)
{
m_pInstance = aCallback.m_pInstance;
m_pMethod = aCallback.m_pMethod;
}
else
{
Callback();
}
return *this;
}
// Are the class instance and method pointers initialised?
bool HasAHandler()
{
return (m_pInstance && m_pMethod);
}
// Execute the associated class method and return the result
Result Fire(Cookie aCookie)
{
if (HasAHandler())
{
return (m_pInstance->*m_pMethod)(aCookie);
}
// Callback is uninitialized, no handler has been assigned
assert(0);
return 0;
}
protected:
Callback* m_pInstance;
MethodPtr m_pMethod;
};
template <class Class, class Result, class Cookie>
class CallbackHandler : public Callback<Result, Cookie>
{
public:
typedef Result (Class::*MethodPtr)(Cookie);
CallbackHandler (Class* pInstance, MethodPtr aMethodPtr)
{
Callback<Result, Cookie>::m_pInstance = (Callback<Result, Cookie>*) ((LPVOID) pInstance);
// Its dirty but it works!
memcpy(&Callback<Result, Cookie>::m_pMethod, &aMethodPtr, sizeof(Callback<Result, Cookie>::m_pMethod));
}
};
#endif // GUICALLBACK_H
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