ceph/src/boost/boost/local_function/aux_/macro/code_/result.hpp

   1
   2 // Copyright (C) 2009-2012 Lorenzo Caminiti
   3 // Distributed under the Boost Software License, Version 1.0
   4 // (see accompanying file LICENSE_1_0.txt or a copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6 // Home at http://www.boost.org/libs/local_function
   7
   8 #ifndef BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_HPP_
   9 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_HPP_
  10
  11 #include <boost/local_function/aux_/symbol.hpp>
  12 #include <boost/local_function/aux_/preprocessor/traits/decl_returns.hpp>
  13 #include <boost/scope_exit.hpp>
  14 #include <boost/typeof/typeof.hpp>
  15 #include <boost/type_traits/remove_pointer.hpp>
  16 #include <boost/type_traits/function_traits.hpp>
  17 #include <boost/preprocessor/control/iif.hpp>
  18 #include <boost/preprocessor/control/expr_iif.hpp>
  19 #include <boost/preprocessor/list/adt.hpp>
  20 #include <boost/preprocessor/cat.hpp>
  21
  22 // PRIVATE //
  23
  24 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_FUNC_(id) \
  25     /* symbol (not internal) also gives error if missing result type */ \
  26     BOOST_PP_CAT( \
  27   ERROR_missing_result_type_before_the_local_function_parameter_macro_id, \
  28             id)
  29
  30 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_PARAMS_(id) \
  31     BOOST_LOCAL_FUNCTION_AUX_SYMBOL( (deduce_result_params)(id) )
  32
  33 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_TYPE_(id) \
  34     BOOST_LOCAL_FUNCTION_AUX_SYMBOL( (result_type)(id) )
  35
  36 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_INDEX_ \
  37     /* this does not have to be an integral index because ScopeExit uses */ \
  38     /* just as a symbol to concatenate go generate unique symbols (but */ \
  39     /* if it'd ever needed to became integral, the number of function */ \
  40     /* params + 1 as in the macro CONFIG_ARITY_MAX could be used) */ \
  41     result
  42
  43 // User did not explicitly specified result type, deduce it (using Typeof).
  44 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_DEDUCE_( \
  45         id, typename01, decl_traits) \
  46     /* user specified result type here */ \
  47     BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_DECL(id) \
  48     /* tagging, wrapping, etc as from ScopeExit type deduction are */ \
  49     /* necessary within templates (at least on GCC) to work around an */ \
  50     /* compiler internal errors) */ \
  51     BOOST_SCOPE_EXIT_DETAIL_TAG_DECL(0, /* no recursive step r */ \
  52             id, BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_INDEX_, \
  53             BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_FUNC_(id)) \
  54     BOOST_SCOPE_EXIT_DETAIL_CAPTURE_DECL(0, /* no recursive step r */ \
  55             ( id, BOOST_PP_EXPR_IIF(typename01, typename) ), \
  56             BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_INDEX_, \
  57             BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_FUNC_(id)) \
  58     /* extra struct to workaround GCC and other compiler's issues */ \
  59     struct BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_PARAMS_(id) { \
  60         typedef \
  61             BOOST_PP_EXPR_IIF(typename01, typename) \
  62             ::boost::function_traits< \
  63                 BOOST_PP_EXPR_IIF(typename01, typename) \
  64                 ::boost::remove_pointer< \
  65                     BOOST_SCOPE_EXIT_DETAIL_CAPTURE_T(id, \
  66                             BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_INDEX_, \
  67                             BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_FUNC_(id)) \
  68                 >::type \
  69             >::result_type \
  70             BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_TYPE_(id) \
  71         ; \
  72     };
  73
  74 // Use result type as explicitly specified by user (no type deduction needed).
  75 // Precondition: RETURNS(decl_traits) != NIL
  76 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_TYPED_( \
  77         id, typename01, decl_traits) \
  78     /* user specified result type here */ \
  79     struct BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_PARAMS_(id) { \
  80         typedef \
  81             BOOST_PP_LIST_FIRST( \
  82                     BOOST_LOCAL_FUNCTION_AUX_PP_DECL_TRAITS_RETURNS( \
  83                             decl_traits)) \
  84             BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_TYPE_(id) \
  85         ; \
  86     };
  87
  88 // PUBLIC //
  89
  90 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_TYPE(id, typename01) \
  91     BOOST_PP_EXPR_IIF(typename01, typename) \
  92     BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_PARAMS_(id) :: \
  93     BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_TYPE_(id)
  94
  95 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_DECL(id) \
  96     /* result type here */ (*BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_FUNC_(id))();
  97
  98 #define BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT(id, typename01, decl_traits) \
  99     BOOST_PP_IIF(BOOST_PP_LIST_IS_CONS( \
 100             BOOST_LOCAL_FUNCTION_AUX_PP_DECL_TRAITS_RETURNS(decl_traits)), \
 101         BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_TYPED_ \
 102     , \
 103         BOOST_LOCAL_FUNCTION_AUX_CODE_RESULT_DEDUCE_ \
 104     )(id, typename01, decl_traits)
 105
 106 #endif // #include guard
 107