Replace generated isInputType functions with concepts

Author: wravery

include/graphqlservice/GraphQLService.h

@@ -592,19 +592,22 @@ enum class [[nodiscard]] TypeModifier {
 	List,
 };
 
-// Specialized to return true for all INPUT_OBJECT types.
+// These types are used as scalar arguments even though they are represented with a class.
 template <typename Type>
-[[nodiscard]] constexpr bool isInputType() noexcept
-{
-	return false;
-}
+concept ScalarArgumentClass = std::is_same_v<Type, std::string> || std::is_same_v<Type,
+	response::IdType> || std::is_same_v<Type, response::Value>;
 
-// Special-case an innermost nullable INPUT_OBJECT type.
+// Any non-scalar class used in an argument is a generated INPUT_OBJECT type.
+template <typename Type>
+concept InputArgumentClass = std::is_class_v<Type> && !ScalarArgumentClass<Type>;
+
+// Test if there are any non-None modifiers left.
 template <TypeModifier... Other>
-[[nodiscard]] constexpr bool onlyNoneModifiers() noexcept
-{
-	return (... && (Other == TypeModifier::None));
-}
+concept OnlyNoneModifiers = (... && (Other == TypeModifier::None));
+
+// Special-case an innermost nullable INPUT_OBJECT type.
+template <typename Type, TypeModifier... Other>
+concept InputArgumentUniquePtr = InputArgumentClass<Type> && OnlyNoneModifiers<Other...>;
 
 // Extract individual arguments with chained type modifiers which add nullable or list wrappers.
 // If the argument is not optional, use require and let it throw a schema_exception when the
@@ -619,8 +622,8 @@ struct ModifiedArgument
 	{
 		// Peel off modifiers until we get to the underlying type.
 		using type = typename std::conditional_t<TypeModifier::Nullable == Modifier,
-			typename std::conditional_t<isInputType<U>() && onlyNoneModifiers<Other...>(),
-				std::unique_ptr<U>, std::optional<typename ArgumentTraits<U, Other...>::type>>,
+			typename std::conditional_t<InputArgumentUniquePtr<U, Other...>, std::unique_ptr<U>,
+				std::optional<typename ArgumentTraits<U, Other...>::type>>,
 			typename std::conditional_t<TypeModifier::List == Modifier,
 				std::vector<typename ArgumentTraits<U, Other...>::type>, U>>;
 	};
@@ -699,7 +702,7 @@ struct ModifiedArgument
 
 		auto result = require<Other...>(name, arguments);
 
-		if constexpr (isInputType<Type>() && onlyNoneModifiers<Other...>())
+		if constexpr (InputArgumentUniquePtr<Type, Other...>)
 		{
 			return std::make_unique<decltype(result)>(std::move(result));
 		}
@@ -768,7 +771,7 @@ struct ModifiedArgument
 
 		if (nullableValue)
 		{
-			if constexpr (isInputType<Type>() && onlyNoneModifiers<Other...>())
+			if constexpr (InputArgumentUniquePtr<Type, Other...>)
 			{
 				// Special case duplicating the std::unique_ptr.
 				result = std::make_unique<Type>(Type { *nullableValue });

samples/learn/schema/StarWarsSchema.h

@@ -109,16 +109,6 @@ void AddMutationDetails(const std::shared_ptr<schema::ObjectType>& typeMutation,
 std::shared_ptr<schema::Schema> GetSchema();
 
 } // namespace learn
-
-namespace service {
-
-template <>
-[[nodiscard]] constexpr bool isInputType<learn::ReviewInput>() noexcept
-{
-	return true;
-}
-
-} // namespace service
 } // namespace graphql
 
 #endif // STARWARSSCHEMA_H

samples/today/nointrospection/TodaySchema.h

@@ -282,64 +282,6 @@ void AddExpensiveDetails(const std::shared_ptr<schema::ObjectType>& typeExpensiv
 std::shared_ptr<schema::Schema> GetSchema();
 
 } // namespace today
-
-namespace service {
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::CompleteTaskInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::ThirdNestedInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::FourthNestedInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::IncludeNullableSelfInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::IncludeNonNullableListSelfInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::StringOperationFilterInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::SecondNestedInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::ForwardDeclaredInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::FirstNestedInput>() noexcept
-{
-	return true;
-}
-
-} // namespace service
 } // namespace graphql
 
 #endif // TODAYSCHEMA_H

samples/today/schema/TodaySchema.h

@@ -282,64 +282,6 @@ void AddExpensiveDetails(const std::shared_ptr<schema::ObjectType>& typeExpensiv
 std::shared_ptr<schema::Schema> GetSchema();
 
 } // namespace today
-
-namespace service {
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::CompleteTaskInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::ThirdNestedInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::FourthNestedInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::IncludeNullableSelfInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::IncludeNonNullableListSelfInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::StringOperationFilterInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::SecondNestedInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::ForwardDeclaredInput>() noexcept
-{
-	return true;
-}
-
-template <>
-[[nodiscard]] constexpr bool isInputType<today::FirstNestedInput>() noexcept
-{
-	return true;
-}
-
-} // namespace service
 } // namespace graphql
 
 #endif // TODAYSCHEMA_H

samples/validation/schema/ValidationSchema.h

@@ -158,16 +158,6 @@ void AddArgumentsDetails(const std::shared_ptr<schema::ObjectType>& typeArgument
 std::shared_ptr<schema::Schema> GetSchema();
 
 } // namespace validation
-
-namespace service {
-
-template <>
-[[nodiscard]] constexpr bool isInputType<validation::ComplexInput>() noexcept
-{
-	return true;
-}
-
-} // namespace service
 } // namespace graphql
 
 #endif // VALIDATIONSCHEMA_H

src/SchemaGenerator.cpp

@@ -645,32 +645,6 @@ GRAPHQLSERVICE_EXPORT )cpp" << _loader.getSchemaNamespace()
 )cpp";
 	}
 
-	if (!_loader.getInputTypes().empty())
-	{
-		if (schemaNamespace.exit())
-		{
-			headerFile << std::endl;
-		}
-
-		if (serviceNamespace.enter())
-		{
-			headerFile << std::endl;
-		}
-
-		for (const auto& inputType : _loader.getInputTypes())
-		{
-			headerFile << R"cpp(template <>
-[[nodiscard]] constexpr bool isInputType<)cpp"
-					   << _loader.getSchemaNamespace() << R"cpp(::)cpp" << inputType.cppType
-					   << R"cpp(>() noexcept
-{
-	return true;
-}
-
-)cpp";
-		}
-	}
-
 	return true;
 }