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