refactor: split message classes

include/sp/protocol/message/MessageImplOptions.h

@@ -0,0 +1,61 @@
+#pragma once
+
+namespace sp {
+namespace option {
+
+// Provide static numeric ID, to facilitate implementation of GetIdImpl()
+template <std::intmax_t TId>
+struct StaticNumIdImpl {};
+
+// Facilitate implementation of DispatchImpl()
+template <typename TActual>
+struct DispatchImpl {};
+
+// Provide fields of the message, facilitate implementation of
+// ReadImpl(), WriteImpl(), ValidImpl(), etc...
+template <typename TFields>
+struct FieldsImpl {};
+
+}  // namespace option
+
+
+namespace details {
+
+
+
+
+
+template <typename... TOptions>
+class MessageImplParsedOptions;
+
+template <>
+struct MessageImplParsedOptions<> {
+	static const bool HasStaticNumIdImpl = false;
+	static const bool HasDispatchImpl = false;
+	static const bool HasFieldsImpl = false;
+};
+
+
+
+
+
+template <std::intmax_t TId, typename... TOptions>
+struct MessageImplParsedOptions<option::StaticNumIdImpl<TId>, TOptions...> : public MessageImplParsedOptions<TOptions...> {
+	static const bool HasStaticNumIdImpl = true;
+	static const std::intmax_t MsgId = TId;
+};
+
+template <typename TActual, typename... TOptions>
+struct MessageImplParsedOptions<option::DispatchImpl<TActual>, TOptions...> : public MessageImplParsedOptions<TOptions...> {
+	static const bool HasDispatchImpl = true;
+	using ActualMessage = TActual;
+};
+
+template <typename TFields, typename... TOptions>
+struct MessageImplParsedOptions<option::FieldsImpl<TFields>, TOptions...> : public MessageImplParsedOptions<TOptions...> {
+	static const bool HasFieldsImpl = true;
+	using Fields = TFields;
+};
+
+}  // namespace details
+}  // namespace sp