iox-eclipse-iceoryx#591 Added void_t to type_traits

Signed-off-by: Hintz Martin (XC-AD/ESW1-J1) <[email protected]>
boschglobal · Mar 3, 2021 · f0f24b4 · f0f24b4
1 parent b411f5e
commit f0f24b4
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Showing 3 changed files with 42 additions and 1 deletion.
diff --git a/iceoryx_utils/include/iceoryx_utils/cxx/type_traits.hpp b/iceoryx_utils/include/iceoryx_utils/cxx/type_traits.hpp
@@ -72,6 +72,9 @@ template <typename T1, typename T2>
 using not_same = typename std::
     integral_constant<bool, !bool(std::is_same<typename std::decay<T1>::type, typename std::decay<T2>::type>::value)>;
 
+/// @brief Maps a sequence of any types to the type void
+template <typename...>
+using void_t = void;
 } // namespace cxx
 } // namespace iox
 

diff --git a/iceoryx_utils/include/iceoryx_utils/internal/cxx/expected.inl b/iceoryx_utils/include/iceoryx_utils/internal/cxx/expected.inl
@@ -29,7 +29,7 @@ struct HasInvalidStateMember : std::false_type
 {
 };
 template <typename T>
-struct HasInvalidStateMember<T, std::void_t<decltype(T::INVALID_STATE)>> : std::true_type
+struct HasInvalidStateMember<T, iox::cxx::void_t<decltype(T::INVALID_STATE)>> : std::true_type
 {
 };
 template <typename... T>

diff --git a/iceoryx_utils/test/moduletests/test_cxx_type_traits.cpp b/iceoryx_utils/test/moduletests/test_cxx_type_traits.cpp
@@ -59,3 +59,41 @@ TEST(TypeTraitsTest, NotSameIsFalse)
     auto sut = not_same<int, int>::value;
     EXPECT_FALSE(sut);
 }
+
+namespace iox
+{
+namespace cxx
+{
+namespace test
+{
+template <typename, typename = void>
+struct has_mytype_as_member : std::false_type
+{
+};
+
+template <typename T>
+struct has_mytype_as_member<T, void_t<typename T::myType>> : std::true_type
+{
+};
+} // namespace test
+} // namespace cxx
+} // namespace iox
+
+TEST(TypeTraitsTest, NoTypeAsMemberIsFalse)
+{
+    struct Sut
+    {
+    };
+
+    EXPECT_FALSE(iox::cxx::test::has_mytype_as_member<Sut>::value);
+}
+
+TEST(TypeTraitsTest, MyTypeAsMemberIsTrue)
+{
+    struct Sut
+    {
+        using myType = int;
+    };
+
+    EXPECT_TRUE(iox::cxx::test::has_mytype_as_member<Sut>::value);
+}