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1 | /* |
2 | * Distributed under the Boost Software License, Version 1.0.(See accompanying | |
3 | * file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) | |
4 | * | |
5 | * See http://www.boost.org/libs/iostreams for documentation. | |
6 | ||
7 | * File: boost/iostreams/detail/execute.hpp | |
8 | * Date: Thu Dec 06 13:21:54 MST 2007 | |
9 | * Copyright: 2007-2008 CodeRage, LLC | |
10 | * Author: Jonathan Turkanis | |
11 | * Contact: turkanis at coderage dot com | |
12 | ||
13 | * Defines the overloaded function template | |
14 | * boost::iostreams::detail::execute_all() and the function template | |
15 | * boost::iostreams::detail::execute_foreach(). | |
16 | * | |
17 | * execute_all() invokes a primary operation and performs a sequence of cleanup | |
18 | * operations, returning the result of the primary operation if no exceptions | |
19 | * are thrown. If one of the operations throws an exception, performs the | |
20 | * remaining operations and rethrows the initial exception. | |
21 | * | |
22 | * execute_foreach() is a variant of std::foreach which invokes a function | |
23 | * object for each item in a sequence, catching all execptions and rethrowing | |
24 | * the first caught exception after the function object has been invoked on each | |
25 | * item. | |
26 | */ | |
27 | ||
28 | #ifndef BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED | |
29 | #define BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED | |
30 | ||
31 | #if defined(_MSC_VER) | |
32 | # pragma once | |
33 | #endif | |
34 | ||
35 | #include <boost/config.hpp> | |
36 | #include <boost/detail/workaround.hpp> | |
37 | #include <boost/iostreams/detail/config/limits.hpp> // MAX_EXECUTE_ARITY | |
38 | #include <boost/preprocessor/arithmetic/dec.hpp> | |
39 | #include <boost/preprocessor/cat.hpp> | |
40 | #include <boost/preprocessor/iteration/local.hpp> | |
41 | #include <boost/preprocessor/repetition/enum_params.hpp> | |
42 | #include <boost/preprocessor/repetition/enum_binary_params.hpp> | |
43 | #include <boost/preprocessor/punctuation/comma_if.hpp> | |
44 | #include <boost/utility/result_of.hpp> | |
45 | ||
46 | namespace boost { namespace iostreams { namespace detail { | |
47 | ||
48 | // Helper for class template execute_traits. | |
49 | template<typename Result> | |
50 | struct execute_traits_impl { | |
51 | typedef Result result_type; | |
52 | template<typename Op> | |
53 | static Result execute(Op op) { return op(); } | |
54 | }; | |
55 | ||
56 | // Specialization for void return. For simplicity, execute() returns int | |
57 | // for operations returning void. This could be avoided with additional work. | |
58 | template<> | |
59 | struct execute_traits_impl<void> { | |
60 | typedef int result_type; | |
61 | template<typename Op> | |
62 | static int execute(Op op) { op(); return 0; } | |
63 | }; | |
64 | ||
65 | // Deduces the result type of Op and allows uniform treatment of operations | |
66 | // returning void and non-void. | |
67 | template< typename Op, | |
68 | typename Result = // VC6.5 workaround. | |
69 | #if !defined(BOOST_NO_RESULT_OF) && \ | |
70 | !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x592)) | |
71 | typename boost::result_of<Op()>::type | |
72 | #else | |
73 | BOOST_DEDUCED_TYPENAME Op::result_type | |
74 | #endif | |
75 | > | |
76 | struct execute_traits | |
77 | : execute_traits_impl<Result> | |
78 | { }; | |
79 | ||
80 | // Implementation with no cleanup operations. | |
81 | template<typename Op> | |
82 | typename execute_traits<Op>::result_type | |
83 | execute_all(Op op) | |
84 | { | |
85 | return execute_traits<Op>::execute(op); | |
86 | } | |
87 | ||
88 | // Implementation with one or more cleanup operations | |
89 | #define BOOST_PP_LOCAL_MACRO(n) \ | |
90 | template<typename Op, BOOST_PP_ENUM_PARAMS(n, typename C)> \ | |
91 | typename execute_traits<Op>::result_type \ | |
92 | execute_all(Op op, BOOST_PP_ENUM_BINARY_PARAMS(n, C, c)) \ | |
93 | { \ | |
94 | typename execute_traits<Op>::result_type r; \ | |
95 | try { \ | |
96 | r = boost::iostreams::detail::execute_all( \ | |
97 | op BOOST_PP_COMMA_IF(BOOST_PP_DEC(n)) \ | |
98 | BOOST_PP_ENUM_PARAMS(BOOST_PP_DEC(n), c) \ | |
99 | ); \ | |
100 | } catch (...) { \ | |
101 | try { \ | |
102 | BOOST_PP_CAT(c, BOOST_PP_DEC(n))(); \ | |
103 | } catch (...) { } \ | |
104 | throw; \ | |
105 | } \ | |
106 | BOOST_PP_CAT(c, BOOST_PP_DEC(n))(); \ | |
107 | return r; \ | |
108 | } \ | |
109 | /**/ | |
110 | ||
111 | #define BOOST_PP_LOCAL_LIMITS (1, BOOST_IOSTREAMS_MAX_EXECUTE_ARITY) | |
112 | #include BOOST_PP_LOCAL_ITERATE() | |
113 | #undef BOOST_PP_LOCAL_MACRO | |
114 | ||
115 | template<class InIt, class Op> | |
116 | Op execute_foreach(InIt first, InIt last, Op op) | |
117 | { | |
118 | if (first == last) | |
119 | return op; | |
120 | try { | |
121 | op(*first); | |
122 | } catch (...) { | |
123 | try { | |
124 | ++first; | |
125 | boost::iostreams::detail::execute_foreach(first, last, op); | |
126 | } catch (...) { } | |
127 | throw; | |
128 | } | |
129 | ++first; | |
130 | return boost::iostreams::detail::execute_foreach(first, last, op); | |
131 | } | |
132 | ||
133 | } } } // End namespaces detail, iostreams, boost. | |
134 | ||
135 | #endif // #ifndef BOOST_IOSTREAMS_DETAIL_EXECUTE_HPP_INCLUDED |