luabind/copy_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_COPY_POLICY_HPP_INCLUDED
  25 #define LUABIND_COPY_POLICY_HPP_INCLUDED
  26
  27 #include <luabind/config.hpp>
  28
  29 #include <boost/type_traits/is_pointer.hpp>
  30 #include <boost/type_traits/is_reference.hpp>
  31 #include <luabind/detail/policy.hpp>
  32
  33 namespace luabind { namespace detail {
  34
  35         struct copy_pointer_to
  36         {
  37                 template<class T>
  38                 void apply(lua_State* L, const T* ptr)
  39                 {
  40                         if (ptr == 0)
  41                         {
  42                                 lua_pushnil(L);
  43                                 return;
  44                         }
  45
  46                         class_registry* registry = class_registry::get_registry(L);
  47
  48                         class_rep* crep = registry->find_class(LUABIND_TYPEID(T));
  49
  50                         // if you get caught in this assert you are trying
  51                         // to use an unregistered type
  52                         assert(crep && "you are trying to use an unregistered type");
  53
  54                         T* copied_obj = new T(*ptr);
  55
  56                         // create the struct to hold the object
  57                         void* obj = lua_newuserdata(L, sizeof(object_rep));
  58                         // we send 0 as destructor since we know it will never be called
  59                         new(obj) object_rep(copied_obj, crep, object_rep::owner, delete_s<T>::apply);
  60
  61                         // set the meta table
  62                         detail::getref(L, crep->metatable_ref());
  63                         lua_setmetatable(L, -2);
  64                 }
  65         };
  66
  67         struct copy_reference_to
  68         {
  69                 template<class T>
  70                 void apply(lua_State* L, const T& ref)
  71                 {
  72                         class_registry* registry = class_registry::get_registry(L);
  73                         class_rep* crep = registry->find_class(LUABIND_TYPEID(T));
  74
  75                         // if you get caught in this assert you are trying
  76                         // to use an unregistered type
  77                         assert(crep && "you are trying to use an unregistered type");
  78
  79                         T* copied_obj = new T(ref);
  80
  81                         // create the struct to hold the object
  82                         void* obj = lua_newuserdata(L, sizeof(object_rep));
  83                         // we send 0 as destructor since we know it will never be called
  84                         new(obj) object_rep(copied_obj, crep, object_rep::owner, delete_s<T>::apply);
  85
  86                         // set the meta table
  87                         detail::getref(L, crep->metatable_ref());
  88                         lua_setmetatable(L, -2);
  89                 }
  90         };
  91
  92         template<int N>
  93         struct copy_policy : conversion_policy<N>
  94         {
  95                 struct only_accepts_pointers_or_references {};
  96                 struct only_converts_from_cpp_to_lua {};
  97
  98                 static void precall(lua_State*, const index_map&) {}
  99                 static void postcall(lua_State*, const index_map&) {}
 100
 101                 template<class T, class Direction>
 102                 struct apply
 103                 {
 104                         typedef typename boost::mpl::if_<boost::is_same<Direction, cpp_to_lua>
 105                                         , typename boost::mpl::if_<boost::is_pointer<T>
 106                                                 ,       copy_pointer_to
 107                                                 ,       typename boost::mpl::if_<boost::is_reference<T>
 108                                                                 ,       copy_reference_to
 109                                                                 ,       only_accepts_pointers_or_references>::type>::type
 110                                         , only_converts_from_cpp_to_lua>::type type;
 111                 };
 112         };
 113 }}
 114
 115 namespace luabind
 116 {
 117         template<int N>
 118         detail::policy_cons<detail::copy_policy<N>, detail::null_type>
 119         copy(LUABIND_PLACEHOLDER_ARG(N))
 120         {
 121                 return detail::policy_cons<detail::copy_policy<N>, detail::null_type>();
 122         }
 123 }
 124
 125 #endif // LUABIND_COPY_POLICY_HPP_INCLUDED
 126