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//
// libavg - Media Playback Engine.
// Copyright (C) 2003-2014 Ulrich von Zadow
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser 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
// 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// Current versions can be found at www.libavg.de
//
#ifndef _Signal_H_
#define _Signal_H_
#include "../api.h"
#include "Exception.h"
#include <list>
namespace avg {
// Simple implementation of a signal/slot mechanism.
// Might need to be replaced by boost::signal when things get more complicated.
template <class LISTENEROBJ>
class AVG_TEMPLATE_API Signal {
public:
typedef void (LISTENEROBJ::*ListenerFunc)() ;
Signal(ListenerFunc pFunc);
virtual ~Signal();
void connect(LISTENEROBJ* pListener);
void disconnect(LISTENEROBJ* pListener);
void emit();
int getNumListeners() const;
private:
ListenerFunc m_pFunc;
std::list<LISTENEROBJ*> m_Listeners;
typedef typename std::list<LISTENEROBJ*>::iterator ListenerIterator;
LISTENEROBJ* m_pCurrentListener;
bool m_bKillCurrentListener;
};
template<class LISTENEROBJ>
Signal<LISTENEROBJ>::Signal(ListenerFunc pFunc)
: m_pFunc(pFunc),
m_pCurrentListener(0),
m_bKillCurrentListener(false)
{
}
template<class LISTENEROBJ>
Signal<LISTENEROBJ>::~Signal()
{
}
template<class LISTENEROBJ>
void Signal<LISTENEROBJ>::connect(LISTENEROBJ* pListener)
{
ListenerIterator it;
it = find(m_Listeners.begin(), m_Listeners.end(), pListener);
// If the listener is already connected, something is wrong, unless we're
// deleting it at this very moment.
AVG_ASSERT(it == m_Listeners.end() ||
(*it == m_pCurrentListener && m_bKillCurrentListener));
m_Listeners.push_back(pListener);
}
template<class LISTENEROBJ>
void Signal<LISTENEROBJ>::disconnect(LISTENEROBJ* pListener)
{
if (m_pCurrentListener == pListener) {
m_bKillCurrentListener = true;
} else {
ListenerIterator it;
it = find(m_Listeners.begin(), m_Listeners.end(), pListener);
AVG_ASSERT(it != m_Listeners.end());
m_Listeners.erase(it);
}
}
template<class LISTENEROBJ>
void Signal<LISTENEROBJ>::emit()
{
ListenerIterator it;
for (it=m_Listeners.begin(); it != m_Listeners.end();) {
m_pCurrentListener = *it;
((*it)->*m_pFunc)(); // This is the actual call to the listener.
if (m_bKillCurrentListener) {
it = m_Listeners.erase(it);
m_bKillCurrentListener = false;
} else {
++it;
}
}
m_pCurrentListener = 0;
}
template<class LISTENEROBJ>
int Signal<LISTENEROBJ>::getNumListeners() const
{
return m_Listeners.size();
}
}
#endif
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