Index: ps/trunk/source/network/NetClient.cpp
===================================================================
--- ps/trunk/source/network/NetClient.cpp
+++ ps/trunk/source/network/NetClient.cpp
@@ -391,7 +391,7 @@
 {
 	// Handle non-FSM messages first
 
-	Status status = m_Session->GetFileTransferer().HandleMessageReceive(message);
+	Status status = m_Session->GetFileTransferer().HandleMessageReceive(*message);
 	if (status == INFO::OK)
 		return true;
 	if (status != INFO::SKIPPED)
Index: ps/trunk/source/network/NetFileTransfer.h
===================================================================
--- ps/trunk/source/network/NetFileTransfer.h
+++ ps/trunk/source/network/NetFileTransfer.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2016 Wildfire Games.
+/* Copyright (C) 2019 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -21,6 +21,9 @@
 #include <map>
 
 class CNetMessage;
+class CFileTransferResponseMessage;
+class CFileTransferDataMessage;
+class CFileTransferAckMessage;
 class CNetClientSession;
 class CNetServerSession;
 class INetSession;
@@ -84,7 +87,7 @@
 	 * Returns INFO::OK if the message is handled successfully,
 	 * or ERR::FAIL if handled unsuccessfully.
 	 */
-	Status HandleMessageReceive(const CNetMessage* message);
+	Status HandleMessageReceive(const CNetMessage& message);
 
 	/**
 	 * Registers a file-receiving task.
@@ -105,6 +108,10 @@
 	void Poll();
 
 private:
+	Status OnFileTransferResponse(const CFileTransferResponseMessage& message);
+	Status OnFileTransferData(const CFileTransferDataMessage& message);
+	Status OnFileTransferAck(const CFileTransferAckMessage& message);
+
 	/**
 	 * Asynchronous file-sending task.
 	 */
@@ -121,10 +128,10 @@
 
 	u32 m_NextRequestID;
 
-	typedef std::map<u32, shared_ptr<CNetFileReceiveTask>> FileReceiveTasksMap;
+	using FileReceiveTasksMap = std::map<u32, shared_ptr<CNetFileReceiveTask> >;
 	FileReceiveTasksMap m_FileReceiveTasks;
 
-	typedef std::map<u32, CNetFileSendTask> FileSendTasksMap;
+	using FileSendTasksMap = std::map<u32, CNetFileSendTask>;
 	FileSendTasksMap m_FileSendTasks;
 
 	double m_LastProgressReportTime;
Index: ps/trunk/source/network/NetFileTransfer.cpp
===================================================================
--- ps/trunk/source/network/NetFileTransfer.cpp
+++ ps/trunk/source/network/NetFileTransfer.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2016 Wildfire Games.
+/* Copyright (C) 2019 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -24,107 +24,119 @@
 #include "network/NetSession.h"
 #include "ps/CLogger.h"
 
-Status CNetFileTransferer::HandleMessageReceive(const CNetMessage* message)
+Status CNetFileTransferer::HandleMessageReceive(const CNetMessage& message)
 {
-	if (message->GetType() == NMT_FILE_TRANSFER_RESPONSE)
+	switch (message.GetType())
 	{
-		CFileTransferResponseMessage* respMessage = (CFileTransferResponseMessage*)message;
+	case NMT_FILE_TRANSFER_RESPONSE:
+		return OnFileTransferResponse(static_cast<const CFileTransferResponseMessage&>(message));
 
-		if (m_FileReceiveTasks.find(respMessage->m_RequestID) == m_FileReceiveTasks.end())
-		{
-			LOGERROR("Net transfer: Unsolicited file transfer response (id=%d)", (int)respMessage->m_RequestID);
-			return ERR::FAIL;
-		}
-
-		if (respMessage->m_Length == 0 || respMessage->m_Length > MAX_FILE_TRANSFER_SIZE)
-		{
-			LOGERROR("Net transfer: Invalid size for file transfer response (length=%d)", (int)respMessage->m_Length);
-			return ERR::FAIL;
-		}
-
-		shared_ptr<CNetFileReceiveTask> task = m_FileReceiveTasks[respMessage->m_RequestID];
+	case NMT_FILE_TRANSFER_DATA:
+		return OnFileTransferData(static_cast<const CFileTransferDataMessage&>(message));
 
-		task->m_Length = respMessage->m_Length;
-		task->m_Buffer.reserve(respMessage->m_Length);
+	case NMT_FILE_TRANSFER_ACK:
+		return OnFileTransferAck(static_cast<const CFileTransferAckMessage&>(message));
 
-		LOGMESSAGERENDER("Downloading data over network (%d KB) - please wait...", (int)(task->m_Length/1024));
-		m_LastProgressReportTime = timer_Time();
+	default:
+		return INFO::SKIPPED;
+	}
+}
 
-		return INFO::OK;
+Status CNetFileTransferer::OnFileTransferResponse(const CFileTransferResponseMessage& message)
+{
+	const FileReceiveTasksMap::iterator it = m_FileReceiveTasks.find(message.m_RequestID);
+	if (it == m_FileReceiveTasks.end())
+	{
+		LOGERROR("Net transfer: Unsolicited file transfer response (id=%lu)", message.m_RequestID);
+		return ERR::FAIL;
 	}
-	else if (message->GetType() == NMT_FILE_TRANSFER_DATA)
+
+	if (message.m_Length == 0 || message.m_Length > MAX_FILE_TRANSFER_SIZE)
 	{
-		CFileTransferDataMessage* dataMessage = (CFileTransferDataMessage*)message;
+		LOGERROR("Net transfer: Invalid size for file transfer response (length=%lu)", message.m_Length);
+		return ERR::FAIL;
+	}
 
-		if (m_FileReceiveTasks.find(dataMessage->m_RequestID) == m_FileReceiveTasks.end())
-		{
-			LOGERROR("Net transfer: Unsolicited file transfer data (id=%d)", (int)dataMessage->m_RequestID);
-			return ERR::FAIL;
-		}
+	CNetFileReceiveTask& task = *it->second;
 
-		shared_ptr<CNetFileReceiveTask> task = m_FileReceiveTasks[dataMessage->m_RequestID];
+	task.m_Length = message.m_Length;
+	task.m_Buffer.reserve(message.m_Length);
 
-		task->m_Buffer += dataMessage->m_Data;
+	LOGMESSAGERENDER("Downloading data over network (%lu KB) - please wait...", task.m_Length / 1024);
+	m_LastProgressReportTime = timer_Time();
 
-		if (task->m_Buffer.size() > task->m_Length)
-		{
-			LOGERROR("Net transfer: Invalid size for file transfer data (length=%d actual=%d)", (int)task->m_Length, (int)task->m_Buffer.size());
-			return ERR::FAIL;
-		}
+	return INFO::OK;
+}
 
-		CFileTransferAckMessage ackMessage;
-		ackMessage.m_RequestID = task->m_RequestID;
-		ackMessage.m_NumPackets = 1; // TODO: would be nice to send a single ack for multiple packets at once
-		m_Session->SendMessage(&ackMessage);
+Status CNetFileTransferer::OnFileTransferData(const CFileTransferDataMessage& message)
+{
+	FileReceiveTasksMap::iterator it = m_FileReceiveTasks.find(message.m_RequestID);
+	if (it == m_FileReceiveTasks.end())
+	{
+		LOGERROR("Net transfer: Unsolicited file transfer data (id=%lu)", message.m_RequestID);
+		return ERR::FAIL;
+	}
 
-		if (task->m_Buffer.size() == task->m_Length)
-		{
-			LOGMESSAGERENDER("Download completed");
+	CNetFileReceiveTask& task = *it->second;
 
-			task->OnComplete();
-			m_FileReceiveTasks.erase(dataMessage->m_RequestID);
-			return INFO::OK;
-		}
+	task.m_Buffer += message.m_Data;
 
-		// TODO: should report progress using proper GUI
+	if (task.m_Buffer.size() > task.m_Length)
+	{
+		LOGERROR("Net transfer: Invalid size for file transfer data (length=%lu actual=%zu)", task.m_Length, task.m_Buffer.size());
+		return ERR::FAIL;
+	}
 
-		// Report the download status occassionally
-		double t = timer_Time();
-		if (t > m_LastProgressReportTime + 0.5)
-		{
-			LOGMESSAGERENDER("Downloading data: %.1f%% of %d KB", 100.f*task->m_Buffer.size()/task->m_Length, (int)(task->m_Length/1024));
-			m_LastProgressReportTime = t;
-		}
+	CFileTransferAckMessage ackMessage;
+	ackMessage.m_RequestID = task.m_RequestID;
+	ackMessage.m_NumPackets = 1; // TODO: would be nice to send a single ack for multiple packets at once
+	m_Session->SendMessage(&ackMessage);
+
+	if (task.m_Buffer.size() == task.m_Length)
+	{
+		LOGMESSAGERENDER("Download completed");
 
+		task.OnComplete();
+		m_FileReceiveTasks.erase(message.m_RequestID);
 		return INFO::OK;
 	}
-	else if (message->GetType() == NMT_FILE_TRANSFER_ACK)
-	{
-		CFileTransferAckMessage* ackMessage = (CFileTransferAckMessage*)message;
 
-		if (m_FileSendTasks.find(ackMessage->m_RequestID) == m_FileSendTasks.end())
-		{
-			LOGERROR("Net transfer: Unsolicited file transfer ack (id=%d)", (int)ackMessage->m_RequestID);
-			return ERR::FAIL;
-		}
+	// TODO: should report progress using proper GUI
 
-		CNetFileSendTask& task = m_FileSendTasks[ackMessage->m_RequestID];
+	// Report the download status occassionally
+	double t = timer_Time();
+	if (t > m_LastProgressReportTime + 0.5)
+	{
+		LOGMESSAGERENDER("Downloading data: %.1f%% of %lu KB", 100.f * task.m_Buffer.size() / task.m_Length, task.m_Length / 1024);
+		m_LastProgressReportTime = t;
+	}
 
-		if (ackMessage->m_NumPackets > task.packetsInFlight)
-		{
-			LOGERROR("Net transfer: Invalid num packets for file transfer ack (num=%d inflight=%d)",
-				(int)ackMessage->m_NumPackets, (int)task.packetsInFlight);
-			return ERR::FAIL;
-		}
+	return INFO::OK;
+}
 
-		task.packetsInFlight -= ackMessage->m_NumPackets;
+Status CNetFileTransferer::OnFileTransferAck(const CFileTransferAckMessage& message)
+{
+	FileSendTasksMap::iterator it = m_FileSendTasks.find(message.m_RequestID);
+	if (it == m_FileSendTasks.end())
+	{
+		LOGERROR("Net transfer: Unsolicited file transfer ack (id=%lu)", message.m_RequestID);
+		return ERR::FAIL;
+	}
 
-		return INFO::OK;
+	CNetFileSendTask& task = it->second;
+
+	if (message.m_NumPackets > task.packetsInFlight)
+	{
+		LOGERROR("Net transfer: Invalid num packets for file transfer ack (num=%lu inflight=%lu)",
+			message.m_NumPackets, task.packetsInFlight);
+		return ERR::FAIL;
 	}
 
-	return INFO::SKIPPED;
-}
+	task.packetsInFlight -= message.m_NumPackets;
 
+	return INFO::OK;
+
+}
 
 void CNetFileTransferer::StartTask(const shared_ptr<CNetFileReceiveTask>& task)
 {
Index: ps/trunk/source/network/NetServer.cpp
===================================================================
--- ps/trunk/source/network/NetServer.cpp
+++ ps/trunk/source/network/NetServer.cpp
@@ -621,7 +621,7 @@
 void CNetServerWorker::HandleMessageReceive(const CNetMessage* message, CNetServerSession* session)
 {
 	// Handle non-FSM messages first
-	Status status = session->GetFileTransferer().HandleMessageReceive(message);
+	Status status = session->GetFileTransferer().HandleMessageReceive(*message);
 	if (status != INFO::SKIPPED)
 		return;