GenericEventNotify.h

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/*

Copyright (C) 2011-2015 Michael Goffioul

This file is part of Octave.

Octave 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 3 of the License, or (at your
option) any later version.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifndef __GenericEventNotify_h__
#define __GenericEventNotify_h__ 1

#include <QSet>

class QEvent;
class QObject;
class QWidget;

namespace QtHandles
{

class GenericEventNotifyReceiver;

class GenericEventNotifySender
{
public:
  GenericEventNotifySender (void) : m_receivers () { }
  virtual ~GenericEventNotifySender (void) { }

  void addReceiver (GenericEventNotifyReceiver* r)
    { m_receivers.insert (r); }

  void removeReceiver (GenericEventNotifyReceiver* r)
    { m_receivers.remove (r); }

protected:
  bool notifyReceiversBefore (QObject* obj, QEvent* evt);
  void notifyReceiversAfter (QObject* obj, QEvent* evt);

private:
  QSet<GenericEventNotifyReceiver*> m_receivers;
};

class GenericEventNotifyReceiver
{
public:
  GenericEventNotifyReceiver (void) { }
  virtual ~GenericEventNotifyReceiver (void) { }

  virtual bool eventNotifyBefore (QObject* obj, QEvent* evt) = 0;
  virtual void eventNotifyAfter (QObject* obj, QEvent* evt) = 0;
};

inline
bool GenericEventNotifySender::notifyReceiversBefore (QObject* obj,
                                                      QEvent* evt)
{
  foreach (GenericEventNotifyReceiver* r, m_receivers)
    if (r->eventNotifyBefore (obj, evt))
      return true;
  return false;
}

inline
void GenericEventNotifySender::notifyReceiversAfter (QObject* obj,
                                                     QEvent* evt)
{
  foreach (GenericEventNotifyReceiver* r, m_receivers)
    r->eventNotifyAfter (obj, evt);
}

#define DECLARE_GENERICEVENTNOTIFY_SENDER(T,B) \
class T : public B, public GenericEventNotifySender \
{ \
public: \
  T (QWidget* xparent) : B (xparent), GenericEventNotifySender () { } \
  ~ T (void) { } \
\
  bool event (QEvent* evt) \
    { \
      bool result = true; \
      if (! notifyReceiversBefore (this, evt)) \
        result = B::event (evt); \
      notifyReceiversAfter (this, evt); \
      return result; \
    } \
}

};

#endif