File indexing completed on 2024-05-05 17:50:04

 /*
    Copyright (C) 2018 Andreas Hartmetz <ahartmetz@gmail.com>
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library 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
    Library General Public License for more details.
 
    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LGPL.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
 
    Alternatively, this file is available under the Mozilla Public License
    Version 1.1.  You may obtain a copy of the License at
    http://www.mozilla.org/MPL/
 */
 
 #ifndef IIOEVENTFORWARDER_H
 #define IIOEVENTFORWARDER_H
 
 #include "iioeventlistener.h"
 #include "iioeventsource.h"
 
 // How to use:
 // - construct with upstream source as constructor argument
 // - connect listener: addIoListener(listener)
 // - use a reimplementation of handleIoReady() to observe I/O
 // - listener will remove itself automatically when it closes the I/O channel, which also causes
 //   the forwarder to remove itself from the source (see removeIoListenerInternal() implementation)
 // - it is possible to start over at this point, if needed (connect listener, etc)
 // NOTE: This connects one source to ONE listener, not one to many like a generic IIoEventSource does.
 //       More is not needed for the use cases of this class (Connection and Server).
 class IIoEventForwarder : public IIoEventListener, public IIoEventSource
 {
 public:
     IIoEventForwarder(IIoEventSource *upstreamSource)
        : m_upstream(upstreamSource) {}
 
     // IO::Status IIOEventListener::handleIoReady(IO::RW rw) override;
     // not overridden - users of this class reimplement it to spy on and/or intercept I/O events!
 
     // IIOEventListener
     FileDescriptor fileDescriptor() const override;
 
     // This only works due to the one-to-one limitation explained above.
     IIoEventListener *downstreamListener();
 
 protected:
     // IIOEventSource
     void addIoListenerInternal(IIoEventListener *iol, uint32 ioRw) override;
     void removeIoListenerInternal(IIoEventListener *iol) override;
     void updateIoInterestInternal(IIoEventListener *iol, uint32 ioRw) override;
 
 private:
     IIoEventSource *m_upstream = nullptr;
     IIoEventListener *m_downstream = nullptr;
 };
 
 #endif // IIOEVENTFORWARDER_H