Creating out of source doc files

1 files changed, 56 insertions, 0 deletions

diff --git a/modules/remote/c++/remote.hpp b/modules/remote/c++/remote.hpp
index 83e6042..62d79c9 100644
--- a/modules/remote/c++/remote.hpp
+++ b/modules/remote/c++/remote.hpp
@@ -5,6 +5,7 @@
 
 #include <forstio/codec/data.hpp>
 #include <forstio/codec/interface.hpp>
+#include <forstio/codec/schema_hash.hpp>
 
 #include <variant>
 
@@ -99,6 +100,61 @@ struct tmpl_group_to_data_client_std_tuple<tmpl_group<T...>, Encoding, Remote> {
 	using type = std::tuple<data_client<T,Encoding,Remote>...>;
 };
 }
+/**
+ * Identifier of an interface function on the wire.
+ *
+ * Keyed on the member name instead of the member index, so reordering an
+ * interface doesn't silently rebind calls between versions.
+ */
+template<string_literal Lit>
+struct rpc_function_id {
+	static constexpr uint32_t value = hash_literal<Lit>::apply(0u);
+};
+
+namespace impl {
+/**
+ * Translates a runtime function id back into the compile time member name
+ * of an interface.
+ *
+ * Needed by every backend where the called function arrives as data instead
+ * of as a template argument.
+ */
+template<typename Iface>
+struct iface_dispatch {
+	static_assert(always_false<Iface>, "Expecting an Interface Type");
+};
+
+template<typename... T, string_literal... Names>
+struct iface_dispatch<schema::Interface<schema::Member<T,Names>...>> {
+	template<typename Ret, uint64_t i, typename Func>
+	static Ret apply_ele(uint32_t func_id, Func& func){
+		if constexpr ( i < sizeof...(Names) ){
+			constexpr string_literal Lit = parameter_key_pack_type<i, Names...>::literal;
+
+			if(func_id == rpc_function_id<Lit>::value){
+				return func.template operator()<Lit>();
+			}
+
+			return apply_ele<Ret, i+1u>(func_id, func);
+		} else {
+			(void) func_id;
+			(void) func;
+			return make_error<err::not_found>("No interface member with this function id");
+		}
+	}
+
+	/**
+	 * Calls func.operator()<Name>() for the member matching the id.
+	 * The return type has to be provided, since there is no member to
+	 * deduce it from if the id doesn't match anything.
+	 */
+	template<typename Ret, typename Func>
+	static Ret apply(uint32_t func_id, Func&& func){
+		return apply_ele<Ret, 0u>(func_id, func);
+	}
+};
+}
+
 template<typename Remote>
 class i_rpc_server {
 protected: