/*
  NODEOPERATION.hpp  -  Specify how the nodes call each other and how processing is organized
 
  Copyright (C)         Lumiera.org
    2008,               Hermann Vosseler <Ichthyostega@web.de>
 
  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 of the
  License, 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 this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
*/


#ifndef ENGINE_NODEOPERATION_H
#define ENGINE_NODEOPERATION_H


#include "proc/engine/procnode.hpp"




namespace engine {
  
  
  
  /**
   * Adapter to shield the ProcNode from the actual buffer management,
   * allowing the processing function within ProcNode to use logical
   * buffer IDs. StateAdapter is created on the stack for each pull()
   * call, using setup/wiring data preconfigured by the builder.
   * Its job is to provide the actual implementation of the Cache
   * push / fetch and recursive downcall to render the source frames.
   */
  class StateAdapter
    : public State
    {
      State& parent_;
      State& current_;
      
    protected:
      StateAdapter (State& callingProcess, WiringDescriptor const&) 
        : parent_ (callingProcess),
          current_(callingProcess.getCurrentImplementation())
        { }
      
      friend class ProcNode; // both are sharing implementation details...
      
      
      virtual State& getCurrentImplementation () { return current_; }
      
      /** contains the details of Cache query and recursive calls
       *  to the predecessor node(s), eventually followed by the 
       *  ProcNode::process() callback
       */
      void retrieve();
    };
  
  
  
} // namespace engine
#endif