Chris@16: #ifndef BOOST_STATECHART_RESULT_HPP_INCLUDED
Chris@16: #define BOOST_STATECHART_RESULT_HPP_INCLUDED
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: // Copyright 2002-2010 Andreas Huber Doenni
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompany-
Chris@16: // ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: #include <boost/assert.hpp>
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: namespace statechart
Chris@16: {
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: enum reaction_result
Chris@16: {
Chris@16:   no_reaction,
Chris@16:   do_forward_event,
Chris@16:   do_discard_event,
Chris@16:   do_defer_event,
Chris@16:   consumed
Chris@16: };
Chris@16: 
Chris@16: struct result_utility;
Chris@16: 
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: class safe_reaction_result
Chris@16: {
Chris@16:   public:
Chris@16:     //////////////////////////////////////////////////////////////////////////
Chris@16:     safe_reaction_result( const safe_reaction_result & other ) :
Chris@16:       reactionResult_( other.reactionResult_ )
Chris@16:     {
Chris@16:       // This assert fails when an attempt is made to make multiple copies of
Chris@16:       // a result value. This makes little sense, given the requirement that
Chris@16:       // an obtained result value must be returned out of the react function.
Chris@16:       BOOST_ASSERT( reactionResult_ != consumed );
Chris@16:       other.reactionResult_ = consumed;
Chris@16:     }
Chris@16: 
Chris@16:     ~safe_reaction_result()
Chris@16:     {
Chris@16:       // This assert fails when an obtained result value is not returned out
Chris@16:       // of the react() function. This can happen if the user accidentally
Chris@16:       // makes more than one call to reaction functions inside react() or
Chris@16:       // accidentally makes one or more calls to reaction functions outside
Chris@16:       // react()
Chris@16:       BOOST_ASSERT( reactionResult_ == consumed );
Chris@16:     }
Chris@16: 
Chris@16:   private:
Chris@16:     //////////////////////////////////////////////////////////////////////////
Chris@16:     safe_reaction_result( reaction_result reactionResult ) :
Chris@16:       reactionResult_( reactionResult )
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     operator reaction_result() const
Chris@16:     {
Chris@16:       const reaction_result val = reactionResult_;
Chris@16:       reactionResult_ = consumed;
Chris@16:       return val;
Chris@16:     }
Chris@16: 
Chris@16:     safe_reaction_result & operator=( const safe_reaction_result & );
Chris@16: 
Chris@16:     mutable reaction_result reactionResult_;
Chris@16: 
Chris@16:     friend struct result_utility;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: #ifdef NDEBUG
Chris@16:   typedef detail::reaction_result result;
Chris@16: #else
Chris@16:   typedef detail::safe_reaction_result result;
Chris@16: #endif
Chris@16: 
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: struct result_utility
Chris@16: {
Chris@16:   static ::boost::statechart::result make_result( reaction_result value )
Chris@16:   {
Chris@16:     return value;
Chris@16:   }
Chris@16: 
Chris@16:   static reaction_result get_result( ::boost::statechart::result value )
Chris@16:   {
Chris@16:     return value;
Chris@16:   }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace statechart
Chris@16: } // namespace boost
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: #endif