luabind/dependency_policy.hpp

   1 // Copyright (c) 2003 Daniel Wallin and Arvid Norberg
   2
   3 // Permission is hereby granted, free of charge, to any person obtaining a
   4 // copy of this software and associated documentation files (the "Software"),
   5 // to deal in the Software without restriction, including without limitation
   6 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
   7 // and/or sell copies of the Software, and to permit persons to whom the
   8 // Software is furnished to do so, subject to the following conditions:
   9
  10 // The above copyright notice and this permission notice shall be included
  11 // in all copies or substantial portions of the Software.
  12
  13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
  14 // ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
  15 // TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
  16 // PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
  17 // SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
  18 // ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  19 // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
  21 // OR OTHER DEALINGS IN THE SOFTWARE.
  22
  23
  24 #ifndef LUABIND_DEPENDENCY_POLICY_HPP_INCLUDED
  25 #define LUABIND_DEPENDENCY_POLICY_HPP_INCLUDED
  26
  27 #include <luabind/config.hpp>
  28 #include <luabind/detail/policy.hpp>
  29
  30 namespace luabind { namespace detail
  31 {
  32         // makes A dependent on B, meaning B will outlive A.
  33         // internally A stores a reference to B
  34         template<int A, int B>
  35         struct dependency_policy
  36         {
  37                 static void postcall(lua_State* L, const index_map& indices)
  38                 {
  39                         int nurse_index = indices[A];
  40                         int patient = indices[B];
  41
  42                         object_rep* nurse = static_cast<object_rep*>(lua_touserdata(L, nurse_index));
  43
  44                         // If the nurse isn't an object_rep, just make this a nop.
  45                         if (nurse == 0)
  46                                 return;
  47
  48                         nurse->add_dependency(L, patient);
  49                 }
  50         };
  51
  52 }}
  53
  54 #if defined (BOOST_MSVC) && (BOOST_MSVC <= 1200)
  55
  56 namespace luabind
  57 {
  58         // most absurd workaround of all time?
  59         namespace detail
  60         {
  61                 template<int N>
  62                 struct size_char_array
  63                 {
  64                         char storage[N + 2];
  65                 };
  66
  67                 template<int N>
  68                 size_char_array<N> deduce_size(LUABIND_PLACEHOLDER_ARG(N));
  69
  70                 template<class T>
  71                 struct get_index_workaround
  72                 {
  73                         static T t;
  74                         BOOST_STATIC_CONSTANT(int, value = sizeof(deduce_size(t)) - 2);
  75                 };
  76         }
  77
  78         template<class A, class B>
  79         detail::policy_cons<detail::dependency_policy<detail::get_index_workaround<A>::value
  80                 , detail::get_index_workaround<B>::value>, detail::null_type> dependency(A,B)
  81         {
  82                 return detail::policy_cons<detail::dependency_policy<
  83                         detail::get_index_workaround<A>::value, detail::get_index_workaround<B>::value>
  84                         , detail::null_type>();
  85         }
  86
  87         template<class A>
  88         detail::policy_cons<detail::dependency_policy<0
  89                 , detail::get_index_workaround<A>::value>, detail::null_type>
  90         return_internal_reference(A)
  91         {
  92                 return detail::policy_cons<detail::dependency_policy<0
  93                         , detail::get_index_workaround<A>::value>, detail::null_type>();
  94         }
  95 }
  96
  97 #else
  98
  99 namespace luabind
 100 {
 101         template<int A, int B>
 102         detail::policy_cons<detail::dependency_policy<A, B>, detail::null_type>
 103         dependency(LUABIND_PLACEHOLDER_ARG(A), LUABIND_PLACEHOLDER_ARG(B))
 104         {
 105                 return detail::policy_cons<detail::dependency_policy<A, B>, detail::null_type>();
 106         }
 107
 108         template<int A>
 109         detail::policy_cons<detail::dependency_policy<0, A>, detail::null_type>
 110         return_internal_reference(LUABIND_PLACEHOLDER_ARG(A))
 111         {
 112                 return detail::policy_cons<detail::dependency_policy<0, A>, detail::null_type>();
 113         }
 114 }
 115
 116 #endif
 117
 118 #endif // LUABIND_DEPENDENCY_POLICY_HPP_INCLUDED
 119