luabind/adopt_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_ADOPT_POLICY_HPP_INCLUDED
  25 #define LUABIND_ADOPT_POLICY_HPP_INCLUDED
  26
  27 #include <luabind/config.hpp>
  28 #include <luabind/wrapper_base.hpp>
  29 #include <luabind/detail/policy.hpp>
  30 #include <luabind/back_reference_fwd.hpp>
  31 #include <luabind/wrapper_base.hpp>
  32 #include <boost/type_traits/is_polymorphic.hpp>
  33
  34 namespace luabind { namespace detail
  35 {
  36     template <class T>
  37     void adjust_backref_ownership(T* ptr, mpl::true_)
  38     {
  39         if (wrap_base* p = dynamic_cast<wrap_base*>(ptr))
  40         {
  41             wrapped_self_t& wrapper = wrap_access::ref(*p);
  42             wrapper.get(wrapper.state());
  43             wrapper.m_strong_ref.set(wrapper.state());
  44         }
  45     }
  46
  47     inline void adjust_backref_ownership(void*, mpl::false_)
  48     {}
  49
  50         template <class Pointer, class Direction = lua_to_cpp>
  51     struct adopt_pointer : pointer_converter
  52         {
  53                 typedef adopt_pointer type;
  54
  55         int const consumed_args(...)
  56         {
  57             return 1;
  58         }
  59
  60                 template<class T>
  61                 T* apply(lua_State* L, by_pointer<T>, int index)
  62                 {
  63             T* ptr = pointer_converter::apply(
  64                 L, LUABIND_DECORATE_TYPE(T*), index);
  65
  66             object_rep* obj = static_cast<object_rep*>(
  67                 lua_touserdata(L, index));
  68             obj->release();
  69
  70             adjust_backref_ownership(ptr, boost::is_polymorphic<T>());
  71
  72             return ptr;
  73                 }
  74
  75                 template<class T>
  76                 int match(lua_State* L, by_pointer<T>, int index)
  77                 {
  78             return pointer_converter::match(
  79                 L, LUABIND_DECORATE_TYPE(T*), index);
  80                 }
  81
  82                 template<class T>
  83                 void converter_postcall(lua_State*, T, int) {}
  84         };
  85
  86     template <class Pointer, class T>
  87     struct pointer_or_default
  88     {
  89         typedef Pointer type;
  90     };
  91
  92     template <class T>
  93     struct pointer_or_default<void, T>
  94     {
  95         typedef std::auto_ptr<T> type;
  96     };
  97
  98         template <class Pointer>
  99         struct adopt_pointer<Pointer, cpp_to_lua>
 100         {
 101                 typedef adopt_pointer type;
 102
 103                 template<class T>
 104                 void apply(lua_State* L, T* ptr)
 105                 {
 106                         if (ptr == 0)
 107                         {
 108                                 lua_pushnil(L);
 109                                 return;
 110                         }
 111
 112                         // if there is a back_reference, then the
 113                         // ownership will be removed from the
 114                         // back reference and put on the lua stack.
 115                         if (luabind::move_back_reference(L, ptr))
 116                                 return;
 117
 118             typedef typename pointer_or_default<Pointer, T>::type
 119                 pointer_type;
 120
 121             make_instance(L, pointer_type(ptr));
 122                 }
 123         };
 124
 125         template <int N, class Pointer = void>
 126         struct adopt_policy : conversion_policy<N>
 127         {
 128 //              BOOST_STATIC_CONSTANT(int, index = N);
 129
 130                 static void precall(lua_State*, const index_map&) {}
 131                 static void postcall(lua_State*, const index_map&) {}
 132
 133                 struct only_accepts_nonconst_pointers {};
 134
 135                 template<class T, class Direction>
 136                 struct apply
 137                 {
 138                         typedef luabind::detail::is_nonconst_pointer<T> is_nonconst_p;
 139                         typedef typename boost::mpl::if_<
 140                 is_nonconst_p
 141               , adopt_pointer<Pointer, Direction>
 142               , only_accepts_nonconst_pointers
 143             >::type type;
 144                 };
 145         };
 146
 147 }}
 148
 149 namespace luabind
 150 {
 151         template<int N>
 152         detail::policy_cons<detail::adopt_policy<N>, detail::null_type>
 153         adopt(LUABIND_PLACEHOLDER_ARG(N))
 154         {
 155                 return detail::policy_cons<detail::adopt_policy<N>, detail::null_type>();
 156         }
 157
 158     template <class Pointer, int N>
 159     detail::policy_cons<detail::adopt_policy<N, Pointer>, detail::null_type>
 160     adopt(LUABIND_PLACEHOLDER_ARG(N))
 161     {
 162         return detail::policy_cons<detail::adopt_policy<N, Pointer>, detail::null_type>();
 163     }
 164 }
 165
 166 #endif // LUABIND_ADOPT_POLICY_HPP_INCLUDE
 167