add deserializer

demo/main.cpp

@@ -1,18 +1,27 @@
 #include "demo.pb.h"
 #include <iostream>
 #include "message_serializer.h"
+#include "message_deserializer.h"
 
 int main()
 {
   demo::demo_message_int dmi;
   dmi.set_data(100);
-  std::cout << dmi.data() << std::endl;
-  std::string dmi_serialized = proto::message_serializer::serialize(dmi);
-
+
   demo::demo_message_string dms;
   dms.set_data("hello world");
+
+  std::cout << dmi.data() << std::endl;
   std::cout << dms.data() << std::endl;  
+
+  std::string dmi_serialized = proto::message_serializer::serialize(dmi);
   std::string dms_serialized = proto::message_serializer::serialize(dms);
+
+  auto dmi_deserialized = proto::message_deserializer::deserialize(dmi_serialized.c_str(), dmi_serialized.length());
+  auto dms_deserialized = proto::message_deserializer::deserialize(dms_serialized.c_str(), dms_serialized.length());
+
+  std::cout << std::dynamic_pointer_cast<demo::demo_message_int>(dmi_deserialized)->data() << std::endl;
+  std::cout << std::dynamic_pointer_cast<demo::demo_message_string>(dms_deserialized)->data() << std::endl;
 
   return 0;
 }

src/CMakeLists.txt

@@ -8,6 +8,8 @@ include_directories(../proto/)
 set(LIB_PROTO_MESSAGE_SRC    
     message_serializer.h
     message_serializer.cpp        
+    message_deserializer.h
+    message_deserializer.cpp        
 )
 
 add_library(lib_proto_message ${LIB_PROTO_MESSAGE_SRC})

src/message_deserializer.cpp

@@ -0,0 +1,32 @@
+#include "message_deserializer.h"
+
+namespace proto {
+    std::shared_ptr<google::protobuf::Message> message_deserializer::deserialize(const char* buf, size_t length) {
+        proto::proto_message proto_message;
+        proto_message.ParseFromArray(buf, length);
+
+        auto message = create_message(proto_message.type());
+
+        if(message){
+            message->ParseFromString(proto_message.payload());
+        }
+
+        return message;
+    }
+
+    std::shared_ptr<google::protobuf::Message> message_deserializer::create_message(const std::string& type_name) {
+        std::shared_ptr<google::protobuf::Message> message = nullptr;
+        auto descriptor = google::protobuf::DescriptorPool::generated_pool()->FindMessageTypeByName(type_name);
+
+        if(descriptor) {
+            auto prototype = google::protobuf::MessageFactory::generated_factory()->GetPrototype(descriptor);
+
+            if(prototype) {
+                message = std::shared_ptr<google::protobuf::Message>(prototype->New());
+            }
+        }
+
+        return message;
+    }
+
+} // proto

src/message_deserializer.h

@@ -0,0 +1,25 @@
+#ifndef MESSAGE_DESERIALIZER_H_
+#define MESSAGE_DESERIALIZER_H_
+
+#include "proto_message.pb.h"
+#include <string>
+#include <memory>
+
+// forward declaration
+namespace google {
+    namespace protobuf {
+        class Message;
+    }
+}
+
+namespace proto {
+    class message_deserializer {
+    public:
+        static std::shared_ptr<google::protobuf::Message> deserialize(const char* buf, size_t length);
+
+    private:
+        static std::shared_ptr<google::protobuf::Message> create_message(const std::string& type_name);
+    };
+} // proto
+
+#endif // MESSAGE_DESERIALIZER_H_