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