Chris@16: /*
Chris@16:  * Distributed under the Boost Software License, Version 1.0.(See accompanying 
Chris@16:  * file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
Chris@16:  * 
Chris@16:  * See http://www.boost.org/libs/iostreams for documentation.
Chris@16: 
Chris@16:  * File:        boost/iostreams/detail/execute.hpp
Chris@16:  * Date:        Thu Dec 06 13:21:54 MST 2007
Chris@16:  * Copyright:   2007-2008 CodeRage, LLC
Chris@16:  * Author:      Jonathan Turkanis
Chris@16:  * Contact:     turkanis at coderage dot com
Chris@16: 
Chris@16:  * Defines the overloaded function template 
Chris@16:  * boost::iostreams::detail::execute_all() and the function template 
Chris@16:  * boost::iostreams::detail::execute_foreach().
Chris@16:  *
Chris@16:  * execute_all() invokes a primary operation and performs a sequence of cleanup 
Chris@16:  * operations, returning the result of the primary operation if no exceptions
Chris@16:  * are thrown. If one of the operations throws an exception, performs the
Chris@16:  * remaining operations and rethrows the initial exception.
Chris@16:  *
Chris@16:  * execute_foreach() is a variant of std::foreach which invokes a function 
Chris@16:  * object for each item in a sequence, catching all execptions and rethrowing
Chris@16:  * the first caught exception after the function object has been invoked on each
Chris@16:  * item.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED
Chris@16: #define BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@16: # pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@16: #include <boost/detail/workaround.hpp>
Chris@16: #include <boost/iostreams/detail/config/limits.hpp>   // MAX_EXECUTE_ARITY
Chris@16: #include <boost/preprocessor/arithmetic/dec.hpp>
Chris@16: #include <boost/preprocessor/cat.hpp>
Chris@16: #include <boost/preprocessor/iteration/local.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_params.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_binary_params.hpp>
Chris@16: #include <boost/preprocessor/punctuation/comma_if.hpp>
Chris@16: #include <boost/utility/result_of.hpp>
Chris@16: 
Chris@16: namespace boost { namespace iostreams { namespace detail {
Chris@16: 
Chris@16: // Helper for class template execute_traits.
Chris@16: template<typename Result>
Chris@16: struct execute_traits_impl {
Chris@16:     typedef Result result_type;
Chris@16:     template<typename Op>
Chris@16:     static Result execute(Op op) { return op(); }
Chris@16: };
Chris@16: 
Chris@16: // Specialization for void return. For simplicity, execute() returns int 
Chris@16: // for operations returning void. This could be avoided with additional work.
Chris@16: template<>
Chris@16: struct execute_traits_impl<void> {
Chris@16:     typedef int result_type;
Chris@16:     template<typename Op>
Chris@16:     static int execute(Op op) { op(); return 0; }
Chris@16: };
Chris@16: 
Chris@16: // Deduces the result type of Op and allows uniform treatment of operations 
Chris@16: // returning void and non-void.
Chris@16: template< typename Op, 
Chris@16:           typename Result = // VC6.5 workaround.
Chris@16:               #if !defined(BOOST_NO_RESULT_OF) && \
Chris@16:                   !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x592))
Chris@16:                   typename boost::result_of<Op()>::type
Chris@16:               #else
Chris@16:                   BOOST_DEDUCED_TYPENAME Op::result_type
Chris@16:               #endif
Chris@16:           >
Chris@16: struct execute_traits 
Chris@16:     : execute_traits_impl<Result>
Chris@16:     { };
Chris@16: 
Chris@16: // Implementation with no cleanup operations.
Chris@16: template<typename Op>
Chris@16: typename execute_traits<Op>::result_type 
Chris@16: execute_all(Op op) 
Chris@16: { 
Chris@16:     return execute_traits<Op>::execute(op);
Chris@16: }
Chris@16: 
Chris@16: // Implementation with one or more cleanup operations
Chris@16: #define BOOST_PP_LOCAL_MACRO(n) \
Chris@16:    template<typename Op, BOOST_PP_ENUM_PARAMS(n, typename C)> \
Chris@16:    typename execute_traits<Op>::result_type \
Chris@16:    execute_all(Op op, BOOST_PP_ENUM_BINARY_PARAMS(n, C, c)) \
Chris@16:    { \
Chris@16:        typename execute_traits<Op>::result_type r; \
Chris@16:        try { \
Chris@16:            r = boost::iostreams::detail::execute_all( \
Chris@16:                    op BOOST_PP_COMMA_IF(BOOST_PP_DEC(n)) \
Chris@16:                    BOOST_PP_ENUM_PARAMS(BOOST_PP_DEC(n), c) \
Chris@16:                ); \
Chris@16:        } catch (...) { \
Chris@16:            try { \
Chris@16:                BOOST_PP_CAT(c, BOOST_PP_DEC(n))(); \
Chris@16:            } catch (...) { } \
Chris@16:            throw; \
Chris@16:        } \
Chris@16:        BOOST_PP_CAT(c, BOOST_PP_DEC(n))(); \
Chris@16:        return r; \
Chris@16:    } \
Chris@16:    /**/
Chris@16: 
Chris@16: #define BOOST_PP_LOCAL_LIMITS (1, BOOST_IOSTREAMS_MAX_EXECUTE_ARITY)
Chris@16: #include BOOST_PP_LOCAL_ITERATE()
Chris@16: #undef BOOST_PP_LOCAL_MACRO
Chris@16: 
Chris@16: template<class InIt, class Op>
Chris@16: Op execute_foreach(InIt first, InIt last, Op op)
Chris@16: {
Chris@16:     if (first == last)
Chris@16:         return op;
Chris@16:     try {
Chris@16:         op(*first);
Chris@16:     } catch (...) {
Chris@16:         try {
Chris@16:             ++first;
Chris@16:             boost::iostreams::detail::execute_foreach(first, last, op);
Chris@16:         } catch (...) { }
Chris@16:         throw;
Chris@16:     }
Chris@16:     ++first;
Chris@16:     return boost::iostreams::detail::execute_foreach(first, last, op);
Chris@16: }
Chris@16: 
Chris@16: } } } // End namespaces detail, iostreams, boost.
Chris@16: 
Chris@16: #endif // #ifndef BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED