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