command-mutation.hpp

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/*
  COMMAND-MUTATION.hpp  -  functor encapsulating the actual operation of steam-Command

  Copyright (C)         Lumiera.org
    2009,               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 CONTROL_COMMAND_MUTATION_H
#define CONTROL_COMMAND_MUTATION_H

#include "lib/error.hpp"
#include "steam/control/command-closure.hpp"
#include "steam/control/memento-tie.hpp"



namespace steam {
namespace control {
  namespace err = lumiera::error;
  
  
  class Mutation
    {
      const CmdFunctor func_;
      
    public:
      template<typename SIG>
      Mutation (function<SIG> const& func)
        : func_(func)
        { }
      
      
      
      void
      operator() (CmdClosure& clo)
        {
          if (!clo)
            throw err::State{"Lifecycle error: function arguments not ready"
                            , LERR_(UNBOUND_ARGUMENTS)};
          clo.invoke (func_);
        }
    };
  
  
  
  
  
  
  
  
  
  class UndoMutation
    : public Mutation
    {
      Mutation captureMemento_;
      
    public:
      template<typename SIG, typename MEM>
      UndoMutation (MementoTie<SIG,MEM> & mementoHolder)
        : Mutation (mementoHolder.tieUndoFunc())
        , captureMemento_(mementoHolder.tieCaptureFunc())
        { }
      
      
      Mutation&
      captureState (CmdClosure& clo)
        {
          if (!clo)
            throw err::State{"need additional function arguments to be able to capture UNDO state"
                            , LERR_(UNBOUND_ARGUMENTS)};
          
          captureMemento_(clo);
          return *this;
        }
      
      
    };
  
  
}} // namespace steam::control
#endif