protocol: Messages must now be created from a MessageTemplate

It shouldn't have been possible to create a Message manually.

include/ki/protocol/dml/Message.h

@@ -1,4 +1,5 @@
 #pragma once
+#include "MessageHeader.h"
 #include "../../util/Serializable.h"
 #include "../../dml/Record.h"
 #include <iostream>
@@ -9,48 +10,40 @@ namespace protocol
 {
 namespace dml
 {
+	class MessageTemplate;
+
 	class Message final : public util::Serializable
 	{
 	public:
-		Message(uint8_t service_id = 0, uint8_t type = 0);
+		Message(const MessageTemplate *message_template = nullptr);
 		virtual ~Message();
 
-		uint8_t get_service_id() const;
-		void set_service_id(uint8_t service_id);
-
-		uint8_t get_type() const;
-		void set_type(uint8_t type);
+		const MessageTemplate *get_template() const;
+		void set_template(const MessageTemplate *message_template);
 
 		ki::dml::Record *get_record();
 		const ki::dml::Record *get_record() const;
 
-		/**
-		 * Sets the record to a copy of the specified record.
-		 */
-		void set_record(const ki::dml::Record &record);
+		ki::dml::FieldBase *get_field(std::string name);
+		const ki::dml::FieldBase *get_field(std::string name) const;
 
-		/**
-		 * If raw data is present, then this uses the specified record 
-		 * to parse the raw DML message payload into a new Record.
-		 * If raw data is not present, this is equivalent to set_record.
-		 * 
-		 * If the raw data is parsed successfully, the internal raw 
-		 * data is cleared, and calls to get_record will return a valid
-		 * Record pointer.
-		 * 
-		 * However, if the raw data is not parsed successfully, then
-		 * calls to get_record will still return nullptr.
-		 */
-		void use_template_record(const ki::dml::Record &record);
+		uint8_t get_service_id() const;
+		uint8_t get_type() const;
+		uint16_t get_message_size() const;
+		std::string get_handler() const;
+		uint8_t get_access_level() const;
 
 		void write_to(std::ostream &ostream) const override final;
 		void read_from(std::istream &istream) override final;
 		size_t get_size() const override final;
 	private:
-		uint8_t m_service_id;
-		uint8_t m_type;
-		std::vector<char> m_raw_data;
+		const MessageTemplate *m_template;
 		ki::dml::Record *m_record;
+
+		// This is used to store raw data when a Message is
+		// constructed without a MessageTemplate.
+		MessageHeader m_header;
+		std::vector<char> m_raw_data;
 	};
 }
 }

include/ki/protocol/dml/MessageBuilder.h

@@ -1,42 +0,0 @@
-#pragma once
-#include "Message.h"
-#include "ki/protocol/exception.h"
-#include <string>
-#include <sstream>
-
-namespace ki
-{
-namespace protocol
-{
-namespace dml
-{
-	class MessageBuilder
-	{
-	public:
-		MessageBuilder(uint8_t service_id = 0, uint8_t type = 0);
-
-		MessageBuilder &set_service_id(uint8_t service_id);
-		MessageBuilder &set_message_type(uint8_t type);
-		MessageBuilder &use_template_record(const ki::dml::Record &record);
-
-		template <typename ValueT>
-		MessageBuilder &set_field_value(std::string name, ValueT value)
-		{
-			auto *field = m_message->get_record()->get_field<ValueT>(name);
-			if (!field)
-			{
-				std::ostringstream oss;
-				oss << "No field with name " << name << " exists with specified type.";
-				throw value_error(oss.str());
-			}
-			field->set_value(value);
-			return *this;
-		}
-
-		Message *get_message() const;
-	private:
-		Message *m_message;
-	};
-}
-}
-}

include/ki/protocol/dml/MessageHeader.h

@@ -0,0 +1,37 @@
+#pragma once
+#include "../../util/Serializable.h"
+#include <iostream>
+
+namespace ki
+{
+namespace protocol
+{
+namespace dml
+{
+	class MessageHeader : public util::Serializable
+	{
+	public:
+		MessageHeader(uint8_t service_id = 0,
+			uint8_t type = 0, uint16_t size = 0);
+		virtual ~MessageHeader() = default;
+
+		uint8_t get_service_id() const;
+		void set_service_id(uint8_t service_id);
+
+		uint8_t get_type() const;
+		void set_type(uint8_t type);
+
+		uint16_t get_message_size() const;
+		void set_message_size(uint16_t size);
+
+		void write_to(std::ostream &ostream) const override final;
+		void read_from(std::istream &istream) override final;
+		size_t get_size() const override final;
+	private:
+		uint8_t m_service_id;
+		uint8_t m_type;
+		uint16_t m_size;
+	};
+}
+}
+}

include/ki/protocol/dml/MessageManager.h

@@ -1,6 +1,6 @@
 #pragma once
+#include "Message.h"
 #include "MessageModule.h"
-#include "MessageBuilder.h"
 #include "../../dml/Record.h"
 #include <string>
 
@@ -20,10 +20,10 @@ namespace dml
 		const MessageModule *get_module(uint8_t service_id) const;
 		const MessageModule *get_module(const std::string &protocol_type) const;
 
-		MessageBuilder &build_message(uint8_t service_id, uint8_t message_type) const;
-		MessageBuilder &build_message(uint8_t service_id, const std::string &message_name) const;
-		MessageBuilder &build_message(const std::string &protocol_type, uint8_t message_type) const;
-		MessageBuilder &build_message(const std::string &protocol_type, const std::string &message_name) const;
+		Message *create_message(uint8_t service_id, uint8_t message_type) const;
+		Message *create_message(uint8_t service_id, const std::string &message_name) const;
+		Message *create_message(const std::string &protocol_type, uint8_t message_type) const;
+		Message *create_message(const std::string &protocol_type, const std::string &message_name) const;
 
 		/**
 		 * If the DML message header cannot be read, then a nullptr

include/ki/protocol/dml/MessageModule.h

@@ -1,4 +1,5 @@
 #pragma once
+#include "Message.h"
 #include "MessageTemplate.h"
 #include <cstdint>
 #include <string>
@@ -33,8 +34,8 @@ namespace dml
 
 		void sort_lookup();
 
-		MessageBuilder &build_message(uint8_t message_type) const;
-		MessageBuilder &build_message(std::string message_name) const;
+		Message *create_message(uint8_t message_type) const;
+		Message *create_message(std::string message_name) const;
 	private:
 		uint8_t m_service_id;
 		std::string m_protocol_type;

include/ki/protocol/dml/MessageTemplate.h

@@ -1,6 +1,6 @@
 #pragma once
 #include "../../dml/Record.h"
-#include "MessageBuilder.h"
+#include "Message.h"
 #include <string>
 
 namespace ki
@@ -25,10 +25,16 @@ namespace dml
 		uint8_t get_service_id() const;
 		void set_service_id(uint8_t service_id);
 
+		std::string get_handler() const;
+		void set_handler(std::string handler);
+
+		uint8_t get_access_level() const;
+		void set_access_level(uint8_t access_level);
+
 		const ki::dml::Record &get_record() const;
 		void set_record(ki::dml::Record *record);
 
-		MessageBuilder &build_message() const;
+		Message *create_message() const;
 	private:
 		std::string m_name;
 		uint8_t m_type;

src/protocol/CMakeLists.txt

@@ -5,7 +5,7 @@ target_sources(${PROJECT_NAME}
 		${PROJECT_SOURCE_DIR}/src/protocol/control/SessionAccept.cpp
 		${PROJECT_SOURCE_DIR}/src/protocol/control/SessionOffer.cpp
 		${PROJECT_SOURCE_DIR}/src/protocol/dml/Message.cpp
-		${PROJECT_SOURCE_DIR}/src/protocol/dml/MessageBuilder.cpp
+		${PROJECT_SOURCE_DIR}/src/protocol/dml/MessageHeader.cpp
 		${PROJECT_SOURCE_DIR}/src/protocol/dml/MessageManager.cpp
 		${PROJECT_SOURCE_DIR}/src/protocol/dml/MessageModule.cpp
 		${PROJECT_SOURCE_DIR}/src/protocol/dml/MessageTemplate.cpp

src/protocol/dml/Message.cpp

@@ -1,4 +1,5 @@
 #include "ki/protocol/dml/Message.h"
+#include "ki/protocol/dml/MessageTemplate.h"
 #include "ki/protocol/exception.h"
 
 namespace ki
@@ -7,11 +8,13 @@ namespace protocol
 {
 namespace dml
 {
-	Message::Message(uint8_t service_id, uint8_t type)
+	Message::Message(const MessageTemplate *message_template)
 	{
-		m_service_id = service_id;
-		m_type = type;
-		m_record = nullptr;
+		m_template = message_template;
+		if (m_template)
+			m_record = new ki::dml::Record(m_template->get_record());
+		else
+			m_record = nullptr;
 	}
 
 	Message::~Message()
@@ -19,24 +22,72 @@ namespace dml
 		delete m_record;
 	}
 
-	uint8_t Message::get_service_id() const
+	const MessageTemplate *Message::get_template() const
 	{
-		return m_service_id;
+		return m_template;
 	}
 
-	void Message::set_service_id(uint8_t service_id)
+	void Message::set_template(const MessageTemplate *message_template)
 	{
-		m_service_id = service_id;
+		m_template = message_template;
+		if (!m_template)
+			return;
+
+		m_record = new ki::dml::Record(message_template->get_record());
+		if (!m_raw_data.empty())
+		{
+			std::istringstream iss(std::string(m_raw_data.data(), m_raw_data.size()));
+			try
+			{
+				m_record->read_from(iss);
+				m_raw_data.clear();
+			}
+			catch (ki::dml::parse_error &e)
+			{
+				delete m_record;
+				m_template = nullptr;
+				m_record = nullptr;
+
+				std::ostringstream oss;
+				oss << "Error reading DML message payload: " << e.what();
+				throw parse_error(oss.str());
+			}
+		}
+	}
+
+	uint8_t Message::get_service_id() const
+	{
+		if (m_template)
+			return m_template->get_service_id();
+		return m_header.get_service_id();
 	}
 
 	uint8_t Message::get_type() const
 	{
-		return m_type;
+		if (m_template)
+			return m_template->get_type();
+		return m_header.get_type();
 	}
 
-	void Message::set_type(uint8_t type)
+	uint16_t Message::get_message_size() const
 	{
-		m_type = type;
+		if (m_record)
+			return m_record->get_size();
+		return m_raw_data.size();
+	}
+
+	std::string Message::get_handler() const
+	{
+		if (m_template)
+			return m_template->get_handler();
+		return "";
+	}
+
+	uint8_t Message::get_access_level() const
+	{
+		if (m_template)
+			return m_template->get_access_level();
+		return 0;
 	}
 
 	ki::dml::Record *Message::get_record()
@@ -49,82 +100,69 @@ namespace dml
 		return m_record;
 	}
 
-	void Message::set_record(const ki::dml::Record &record)
+	ki::dml::FieldBase* Message::get_field(std::string name)
 	{
-		m_record = new ki::dml::Record(record);
+		if  (m_record)
+			return m_record->get_field(name);
+		return nullptr;
 	}
 
-	void Message::use_template_record(const ki::dml::Record &record)
+	const ki::dml::FieldBase* Message::get_field(std::string name) const
 	{
-		set_record(record);
-		if (!m_raw_data.empty())
-		{
-			std::istringstream iss(std::string(m_raw_data.data(), m_raw_data.size()));
-			try
-			{
-				m_record->read_from(iss);
-				m_raw_data.clear();
-			}
-			catch (ki::dml::parse_error &e)
-			{
-				delete m_record;
-				m_record = nullptr;
-
-				std::ostringstream oss;
-				oss << "Error reading DML message payload: " << e.what();
-				throw parse_error(oss.str());
-			}
-		}
+		if (m_record)
+			return m_record->get_field(name);
+		return nullptr;
 	}
 
 	void Message::write_to(std::ostream &ostream) const
 	{
-		ki::dml::Record record;
-		record.add_field<ki::dml::UBYT>("m_service_id")->set_value(m_service_id);
-		record.add_field<ki::dml::UBYT>("m_type")->set_value(m_type);
-		auto *size_field = record.add_field<ki::dml::USHRT>("size");
-		if (m_record)
-			size_field->set_value(m_record->get_size() + 4);
+		// Write the header
+		if (m_template)
+		{
+			MessageHeader header(
+				get_service_id(), get_type(), get_message_size());
+			header.write_to(ostream);
+		}
 		else
-			size_field->set_value(m_raw_data.size() + 4);
-		record.write_to(ostream);
+			m_header.write_to(ostream);
 
+		// Write the payload
 		if (m_record)
-			record.write_to(ostream);
+			m_record->write_to(ostream);
 		else
 			ostream.write(m_raw_data.data(), m_raw_data.size());
 	}
 
 	void Message::read_from(std::istream &istream)
 	{
-		ki::dml::Record record;
-		auto *service_id_field = record.add_field<ki::dml::UBYT>("ServiceID");
-		auto *message_type_field = record.add_field<ki::dml::UBYT>("MsgType");
-		auto *size_field = record.add_field<ki::dml::USHRT>("Length");
-		try
+		m_header.read_from(istream);
+		if (m_template)
 		{
-			record.read_from(istream);
-		}
-		catch (ki::dml::parse_error &e)
-		{
-			std::ostringstream oss;
-			oss << "Error reading DML message header: " << e.what();
-			throw parse_error(oss.str());
-		}
+			// Check for mismatches between the header and template
+			if (m_header.get_service_id() != m_template->get_service_id())
+				throw value_error("ServiceID mismatch between MessageHeader and assigned template.");
+			if (m_header.get_type() != m_template->get_type())
+				throw value_error("Message Type mismatch between MessageHeader and assigned template.");
 
-		m_service_id = service_id_field->get_value();
-		m_type = message_type_field->get_value();
-		const ki::dml::USHRT size = size_field->get_value() - 4;
-		m_raw_data.resize(size);
-		istream.read(m_raw_data.data(), size);
-		if (istream.fail())
-			throw parse_error("Not enough data was available to read DML message payload.");
+			// Read the payload into the record
+			m_record->read_from(istream);
+		}
+		else
+		{
+			// We don't have a template for the record structure, so
+			// just read the raw data into a buffer.
+			const auto size = m_header.get_message_size();
+			m_raw_data.resize(size);
+			istream.read(m_raw_data.data(), size);
+			if (istream.fail())
+				throw parse_error("Not enough data was available to read DML message payload.");
+		}
 	}
 
 	size_t Message::get_size() const
 	{
 		if (m_record)
-			return 4 + m_record->get_size();
+			return m_header.get_size() + m_record->get_size();
 		return 4 + m_raw_data.size();
 	}
 }

src/protocol/dml/MessageBuilder.cpp

@@ -1,38 +0,0 @@
-#include "ki/protocol/dml/MessageBuilder.h"
-
-namespace ki
-{
-namespace protocol
-{
-namespace dml
-{
-	MessageBuilder::MessageBuilder(uint8_t service_id, uint8_t type)
-	{
-		m_message = new Message(service_id, type);
-	}
-
-	MessageBuilder &MessageBuilder::set_service_id(uint8_t service_id)
-	{
-		m_message->set_service_id(service_id);
-		return *this;
-	}
-
-	MessageBuilder &MessageBuilder::set_message_type(uint8_t type)
-	{
-		m_message->set_type(type);
-		return *this;
-	}
-
-	MessageBuilder &MessageBuilder::use_template_record(const ki::dml::Record& record)
-	{
-		m_message->set_record(record);
-		return *this;
-	}
-
-	Message *MessageBuilder::get_message() const
-	{
-		return m_message;
-	}
-}
-}
-}

src/protocol/dml/MessageHeader.cpp

@@ -0,0 +1,88 @@
+#include "ki/protocol/dml/MessageHeader.h"
+#include "ki/dml/Record.h"
+#include "ki/protocol/exception.h"
+
+namespace ki
+{
+namespace protocol
+{
+namespace dml
+{
+	MessageHeader::MessageHeader(const uint8_t service_id,
+		const uint8_t type, const uint16_t size)
+	{
+		m_service_id = service_id;
+		m_type = type;
+		m_size = size;
+	}
+
+	uint8_t MessageHeader::get_service_id() const
+	{
+		return m_service_id;
+	}
+
+	void MessageHeader::set_service_id(const uint8_t service_id)
+	{
+		m_service_id = service_id;
+	}
+
+	uint8_t MessageHeader::get_type() const
+	{
+		return m_type;
+	}
+
+	void MessageHeader::set_type(const uint8_t type)
+	{
+		m_type = type;
+	}
+
+	uint16_t MessageHeader::get_message_size() const
+	{
+		return m_size;
+	}
+
+	void MessageHeader::set_message_size(const uint16_t size)
+	{
+		m_size = size;
+	}
+
+	void MessageHeader::write_to(std::ostream& ostream) const
+	{
+		ki::dml::Record record;
+		record.add_field<ki::dml::UBYT>("m_service_id")->set_value(m_service_id);
+		record.add_field<ki::dml::UBYT>("m_type")->set_value(m_type);
+		record.add_field<ki::dml::USHRT>("m_size")->set_value(m_size + 4);
+		record.write_to(ostream);
+	}
+
+	void MessageHeader::read_from(std::istream& istream)
+	{
+		ki::dml::Record record;
+		const auto *service_id = record.add_field<ki::dml::UBYT>("m_service_id");
+		const auto *type = record.add_field<ki::dml::UBYT>("m_type");
+		const auto size = record.add_field<ki::dml::USHRT>("m_size");
+
+		try
+		{
+			record.read_from(istream);
+		}
+		catch (ki::dml::parse_error &e)
+		{
+			std::ostringstream oss;
+			oss << "Error reading MessageHeader: " << e.what();
+			throw parse_error(oss.str());
+		}
+
+		m_service_id = service_id->get_value();
+		m_type = type->get_value();
+		m_size = size->get_value() - 4;
+	}
+
+	size_t MessageHeader::get_size() const
+	{
+		return sizeof(ki::dml::UBYT) + sizeof(ki::dml::UBYT) +
+			sizeof(ki::dml::USHRT);
+	}
+}
+}
+}

src/protocol/dml/MessageManager.cpp

@@ -1,4 +1,5 @@
 #include "ki/protocol/dml/MessageManager.h"
+#include "ki/protocol/dml/MessageHeader.h"
 #include "ki/protocol/exception.h"
 #include "ki/dml/Record.h"
 #include "ki/util/ValueBytes.h"
@@ -155,7 +156,7 @@ namespace dml
 		return nullptr;
 	}
 
-	MessageBuilder &MessageManager::build_message(uint8_t service_id, uint8_t message_type) const
+	Message *MessageManager::create_message(uint8_t service_id, uint8_t message_type) const
 	{
 		auto *message_module = get_module(service_id);
 		if (!message_module)
@@ -165,10 +166,10 @@ namespace dml
 			throw value_error(oss.str());
 		}
 
-		return message_module->build_message(message_type);
+		return message_module->create_message(message_type);
 	}
 
-	MessageBuilder& MessageManager::build_message(uint8_t service_id, const std::string& message_name) const
+	Message *MessageManager::create_message(uint8_t service_id, const std::string& message_name) const
 	{
 		auto *message_module = get_module(service_id);
 		if (!message_module)
@@ -178,10 +179,10 @@ namespace dml
 			throw value_error(oss.str());
 		}
 
-		return message_module->build_message(message_name);
+		return message_module->create_message(message_name);
 	}
 
-	MessageBuilder& MessageManager::build_message(const std::string& protocol_type, uint8_t message_type) const
+	Message *MessageManager::create_message(const std::string& protocol_type, uint8_t message_type) const
 	{
 		auto *message_module = get_module(protocol_type);
 		if (!message_module)
@@ -191,10 +192,10 @@ namespace dml
 			throw value_error(oss.str());
 		}
 
-		return message_module->build_message(message_type);
+		return message_module->create_message(message_type);
 	}
 
-	MessageBuilder& MessageManager::build_message(const std::string& protocol_type, const std::string& message_name) const
+	Message *MessageManager::create_message(const std::string& protocol_type, const std::string& message_name) const
 	{
 		auto *message_module = get_module(protocol_type);
 		if (!message_module)
@@ -204,35 +205,47 @@ namespace dml
 			throw value_error(oss.str());
 		}
 
-		return message_module->build_message(message_name);
+		return message_module->create_message(message_name);
 	}
 
 	const Message *MessageManager::message_from_binary(std::istream& istream) const
 	{
-		// Read the message header and raw payload
-		Message *message = new Message();
+		// Read the message header
+		MessageHeader header;
 		try
 		{
-			message->read_from(istream);
+			header.read_from(istream);
 		}
 		catch (parse_error &e)
 		{
-			delete message;
 			return nullptr;
 		}
 
 		// Get the message module that uses the specified service id
-		auto *message_module = get_module(message->get_service_id());
+		auto *message_module = get_module(header.get_service_id());
 		if (!message_module)
-			return message;
+			return nullptr;
 
 		// Get the message template for this message type
-		auto *message_template = message_module->get_message_template(message->get_type());
+		auto *message_template = message_module->get_message_template(header.get_type());
 		if (!message_template)
-			return message;
+			return nullptr;
 
-		// Parse the raw payload with the template
-		message->use_template_record(message_template->get_record());
+		// Make sure that the size specified is enough to read this message
+		if (header.get_message_size() < message_template->get_record().get_size())
+			return nullptr;
+
+		// Create a new Message from the template
+		auto *message = new Message(message_template);
+		try
+		{
+			message->get_record()->read_from(istream);
+		}
+		catch (ki::dml::parse_error &e)
+		{
+			delete message;
+			return nullptr;
+		}
 		return message;
 	}
 }

src/protocol/dml/MessageModule.cpp

@@ -139,7 +139,7 @@ namespace dml
 		}
 	}
 
-	MessageBuilder& MessageModule::build_message(uint8_t message_type) const
+	Message *MessageModule::create_message(uint8_t message_type) const
 	{
 		auto *message_template = get_message_template(message_type);
 		if (!message_template)
@@ -150,10 +150,10 @@ namespace dml
 			throw value_error(oss.str());
 		}
 
-		return message_template->build_message();
+		return message_template->create_message();
 	}
 
-	MessageBuilder &MessageModule::build_message(std::string message_name) const
+	Message *MessageModule::create_message(std::string message_name) const
 	{
 		auto *message_template = get_message_template(message_name);
 		if (!message_template)
@@ -164,7 +164,7 @@ namespace dml
 			throw value_error(oss.str());
 		}
 
-		return message_template->build_message();
+		return message_template->create_message();
 	}
 }
 }

src/protocol/dml/MessageTemplate.cpp

@@ -50,6 +50,32 @@ namespace dml
 		m_service_id = service_id;
 	}
 
+	std::string MessageTemplate::get_handler() const
+	{
+		const auto field = m_record->get_field<ki::dml::STR>("_MsgHandler");
+		if (field)
+			return field->get_value();
+		return m_name;
+	}
+
+	void MessageTemplate::set_handler(std::string handler)
+	{
+		m_record->add_field<ki::dml::STR>("_MsgHandler")->set_value(handler);
+	}
+
+	uint8_t MessageTemplate::get_access_level() const
+	{
+		const auto field = m_record->get_field<ki::dml::UBYT>("_MsgAccessLvl");
+		if (field)
+			return field->get_value();
+		return 0;
+	}
+
+	void MessageTemplate::set_access_level(uint8_t access_level)
+	{
+		m_record->add_field<ki::dml::UBYT>("_MsgAccessLvl")->set_value(access_level);
+	}
+
 	const ki::dml::Record& MessageTemplate::get_record() const
 	{
 		return *m_record;
@@ -60,12 +86,9 @@ namespace dml
 		m_record = record;
 	}
 
-	MessageBuilder &MessageTemplate::build_message() const
+	Message *MessageTemplate::create_message() const
 	{
-		return MessageBuilder()
-			.set_message_type(m_type)
-			.set_service_id(m_service_id)
-			.use_template_record(*m_record);
+		return new Message(this);
 	}
 }
 }