1 files changed, 119 insertions, 0 deletions
diff --git a/src/base/Signal.h b/src/base/Signal.h
new file mode 100644
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--- /dev/null
+++ b/src/base/Signal.h
@@ -0,0 +1,119 @@
+//
+//  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