refactor message serializer to allow access to eg contacts

src/fragment_store/message_serializer.hpp

@@ -0,0 +1,85 @@
+#pragma once
+
+#include <entt/core/type_info.hpp>
+#include <entt/container/dense_map.hpp>
+
+#include <solanaceae/message3/registry_message_model.hpp>
+
+#include <nlohmann/json_fwd.hpp>
+
+struct MessageSerializerCallbacks {
+	using Registry = Message3Registry;
+	using Handle = Message3Handle;
+
+	Contact3Registry& cr;
+
+	// nlohmann
+	// json/msgpack
+	using serialize_json_fn = bool(*)(MessageSerializerCallbacks& msc, const Handle h, nlohmann::json& out);
+	entt::dense_map<entt::id_type, serialize_json_fn> _serl_json;
+
+	using deserialize_json_fn = bool(*)(MessageSerializerCallbacks& msc, Handle h, const nlohmann::json& in);
+	entt::dense_map<entt::id_type, deserialize_json_fn> _deserl_json;
+
+	template<typename T>
+	static bool component_get_json(MessageSerializerCallbacks&, const Handle h, nlohmann::json& j) {
+		if (h.template all_of<T>()) {
+			if constexpr (!std::is_empty_v<T>) {
+				j = h.template get<T>();
+			}
+			return true;
+		}
+
+		return false;
+	}
+
+	template<typename T>
+	static bool component_emplace_or_replace_json(MessageSerializerCallbacks&, Handle h, const nlohmann::json& j) {
+		if constexpr (std::is_empty_v<T>) {
+			h.template emplace_or_replace<T>(); // assert empty json?
+		} else {
+			h.template emplace_or_replace<T>(static_cast<T>(j));
+		}
+		return true;
+	}
+
+	void registerSerializerJson(serialize_json_fn fn, const entt::type_info& type_info) {
+		_serl_json[type_info.hash()] = fn;
+	}
+
+	template<typename CompType>
+	void registerSerializerJson(
+		serialize_json_fn fn = component_get_json<CompType>,
+		const entt::type_info& type_info = entt::type_id<CompType>()
+	) {
+		registerSerializerJson(fn, type_info);
+	}
+
+	void registerDeSerializerJson(deserialize_json_fn fn, const entt::type_info& type_info) {
+		_deserl_json[type_info.hash()] = fn;
+	}
+
+	template<typename CompType>
+	void registerDeSerializerJson(
+		deserialize_json_fn fn = component_emplace_or_replace_json<CompType>,
+		const entt::type_info& type_info = entt::type_id<CompType>()
+	) {
+		registerDeSerializerJson(fn, type_info);
+	}
+};
+
+// fwd
+namespace Message::Components {
+struct ContactFrom;
+struct ContactTo;
+}
+
+// make specializations known
+template<>
+bool MessageSerializerCallbacks::component_get_json<Message::Components::ContactFrom>(MessageSerializerCallbacks& msc, const Handle h, nlohmann::json& j);
+template<>
+bool MessageSerializerCallbacks::component_emplace_or_replace_json<Message::Components::ContactFrom>(MessageSerializerCallbacks& msc, Handle h, const nlohmann::json& j);
+template<>
+bool MessageSerializerCallbacks::component_get_json<Message::Components::ContactTo>(MessageSerializerCallbacks& msc, const Handle h, nlohmann::json& j);
+template<>
+bool MessageSerializerCallbacks::component_emplace_or_replace_json<Message::Components::ContactTo>(MessageSerializerCallbacks& msc, Handle h, const nlohmann::json& j);