Add support for conversion between Lua and rvalue references.

With C++11, boost::make_shared and std::make_shared use rvalue references to forward constructor arguments without copying. If the macro BOOST_HAS_RVALUE_REFS is defined, let the type trait is_nonconst_reference evaluate to true only for lvalue references. Use value_converter for rvalue reference types. Add specialisations for rvalue references of default_converter of number types, bool, std::string and boost::shared_ptr. Note that support of rvalue references requires Boost ≥ 1.44.0. Conflicts: luabind/detail/decorate_type.hpp luabind/detail/typetraits.hpp
Oberon00 · Jun 30, 2013 · 950e1e3 · 950e1e3
1 parent ca8ce7b
commit 950e1e3
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diff --git a/luabind/detail/decorate_type.hpp b/luabind/detail/decorate_type.hpp
@@ -92,6 +92,18 @@ namespace luabind { namespace detail
     template<class T>
     by_const_reference<T> decorated_type<const T&>::t;
 
+#ifdef BOOST_HAS_RVALUE_REFS
+    template<class T>
+    struct decorated_type<T&&>
+    {
+        static by_value<T> t;
+        static inline by_value<T>& get() { return /*by_value<T>()*/t; }
+    };
+
+    template<class T>
+    by_value<T> decorated_type<T&&>::t;
+#endif
+
     #define LUABIND_DECORATE_TYPE(t) luabind::detail::decorated_type<t>::get()
 
 #else

diff --git a/luabind/detail/policy.hpp b/luabind/detail/policy.hpp
@@ -674,6 +674,46 @@ lua_Number as_lua_number(T v)
     return static_cast<lua_Number>(v);
 }
 
+#ifdef BOOST_HAS_RVALUE_REFS
+
+# define LUABIND_NUMBER_CONVERTER(type, kind) \
+    template <> \
+struct default_converter<type> \
+  : native_converter_base<type> \
+{ \
+    int compute_score(lua_State* L, int index) \
+    { \
+        return lua_type(L, index) == LUA_TNUMBER ? 0 : -1; \
+    }; \
+    \
+    type from(lua_State* L, int index) \
+    { \
+        return static_cast<type>(BOOST_PP_CAT(lua_to, kind)(L, index)); \
+    } \
+    \
+    void to(lua_State* L, type const& value) \
+    { \
+        BOOST_PP_CAT(lua_push, kind)(L, BOOST_PP_CAT(as_lua_, kind)(value)); \
+    } \
+}; \
+\
+template <> \
+struct default_converter<type const> \
+  : default_converter<type> \
+{}; \
+\
+template <> \
+struct default_converter<type const&> \
+  : default_converter<type> \
+{}; \
+\
+template <> \
+struct default_converter<type&&> \
+  : default_converter<type> \
+{};
+
+#else
+
 # define LUABIND_NUMBER_CONVERTER(type, kind) \
     template <> \
 struct default_converter<type> \
@@ -705,6 +745,8 @@ struct default_converter<type const&> \
   : default_converter<type> \
 {};
 
+#endif
+
 LUABIND_NUMBER_CONVERTER(char, integer)
 LUABIND_NUMBER_CONVERTER(signed char, integer)
 LUABIND_NUMBER_CONVERTER(unsigned char, integer)
@@ -752,6 +794,13 @@ struct default_converter<bool const&>
   : default_converter<bool>
 {};
 
+#ifdef BOOST_HAS_RVALUE_REFS
+template <>
+struct default_converter<bool&&>
+  : default_converter<bool>
+{};
+#endif
+
 template <>
 struct default_converter<std::string>
   : native_converter_base<std::string>
@@ -782,6 +831,13 @@ struct default_converter<std::string const&>
   : default_converter<std::string>
 {};
 
+#ifdef BOOST_HAS_RVALUE_REFS
+template <>
+struct default_converter<std::string&&>
+  : default_converter<std::string>
+{};
+#endif
+
 template <>
 struct default_converter<char const*>
 {

diff --git a/luabind/detail/typetraits.hpp b/luabind/detail/typetraits.hpp
@@ -107,7 +107,11 @@ namespace luabind { namespace detail
     {
         enum
         {
+#ifdef BOOST_HAS_RVALUE_REFS
+            value = boost::is_lvalue_reference<T>::value && !is_const_reference<T>::value
+#else
             value = boost::is_reference<T>::value && !is_const_reference<T>::value
+#endif
         };
         typedef boost::mpl::bool_<value> type;
     };

diff --git a/luabind/shared_ptr_converter.hpp b/luabind/shared_ptr_converter.hpp
@@ -81,6 +81,13 @@ struct default_converter<boost::shared_ptr<T> const&>
   : default_converter<boost::shared_ptr<T> >
 {};
 
+#ifdef BOOST_HAS_RVALUE_REFS
+template <class T>
+struct default_converter<boost::shared_ptr<T>&&>
+  : default_converter<boost::shared_ptr<T> >
+{};
+#endif
+
 } // namespace luabind
 
 #endif // LUABIND_SHARED_PTR_CONVERTER_090211_HPP