Consolidate get_lowest_layer in type_traits.hpp

fix #347
2017-07-20 08:12:16 -07:00
parent 4edd797611
commit f097f401cb
10 changed files with 105 additions and 113 deletions
@@ -14,7 +14,7 @@
 #include <beast/core/error.hpp>
 #include <beast/core/stream_concepts.hpp>
 #include <beast/core/multi_buffer.hpp>
-#include <beast/core/detail/get_lowest_layer.hpp>
+#include <beast/core/detail/type_traits.hpp>
 #include <boost/asio/buffer.hpp>
 #include <boost/asio/io_service.hpp>
 #include <cstdint>
@@ -13,39 +13,6 @@
 namespace beast {
 namespace detail {

-template<class T>
-class has_lowest_layer
-{
-    template<class U, class R =
-        typename U::lowest_layer_type>
-    static std::true_type check(int);
-    template<class>
-    static std::false_type check(...);
-    using type = decltype(check<T>(0));
-public:
-    static bool constexpr value = type::value;
-};
-
-template<class T, bool B>
-struct maybe_get_lowest_layer
-{
-    using type = T;
-};
-
-template<class T>
-struct maybe_get_lowest_layer<T, true>
-{
-    using type = typename T::lowest_layer_type;
-};
-
-// If T has a nested type lowest_layer_type,
-// returns that, else returns T.
-template<class T>
-struct get_lowest_layer
-{
-    using type = typename maybe_get_lowest_layer<T,
-        has_lowest_layer<T>::value>::type;
-};

 } // detail
 } // beast
@@ -127,6 +127,39 @@ struct is_invocable<C, R(A...)>
 };
 /** @} */

+template<class T>
+class has_lowest_layer
+{
+    template<class U, class R =
+        typename U::lowest_layer_type>
+    static std::true_type check(int);
+    template<class>
+    static std::false_type check(...);
+    using type = decltype(check<T>(0));
+public:
+    static bool constexpr value = type::value;
+};
+
+template<class T, bool B>
+struct maybe_get_lowest_layer
+{
+    using type = T;
+};
+
+template<class T>
+struct maybe_get_lowest_layer<T, true>
+{
+    using type = typename T::lowest_layer_type;
+};
+
+// Returns T::lowest_layer_type if it exists, else T
+template<class T>
+struct get_lowest_layer
+{
+    using type = typename maybe_get_lowest_layer<T,
+        has_lowest_layer<T>::value>::type;
+};
+
 } // detail
 } // beast

@@ -17,7 +17,7 @@
 #include <beast/core/async_result.hpp>
 #include <beast/core/buffered_read_stream.hpp>
 #include <beast/core/string_view.hpp>
-#include <beast/core/detail/get_lowest_layer.hpp>
+#include <beast/core/detail/type_traits.hpp>
 #include <boost/asio.hpp>
 #include <algorithm>
 #include <cstdint>