Codechange: [Network] split CloseSocket and CloseConnection more clearly (#9261)

* Codechange: [Network] split CloseSocket and CloseConnection more clearly

- CloseSocket now closes the actual OS socket.
- CloseConnection frees up the resources to just before CloseSocket.
- dtors call CloseSocket / CloseConnection where needed.

src/network/core/tcp.cpp

@@ -29,24 +29,45 @@ NetworkTCPSocketHandler::NetworkTCPSocketHandler(SOCKET s) :
 
 NetworkTCPSocketHandler::~NetworkTCPSocketHandler()
 {
-	/* Virtual functions get called statically in destructors, so make it explicit to remove any confusion. */
-	this->NetworkTCPSocketHandler::CloseConnection();
-
-	if (this->sock != INVALID_SOCKET) closesocket(this->sock);
-	this->sock = INVALID_SOCKET;
+	this->EmptyPacketQueue();
+	this->CloseSocket();
 }
 
-NetworkRecvStatus NetworkTCPSocketHandler::CloseConnection(bool error)
+/**
+ * Free all pending and partially received packets.
+ */
+void NetworkTCPSocketHandler::EmptyPacketQueue()
 {
-	this->writable = false;
-	NetworkSocketHandler::CloseConnection(error);
-
-	/* Free all pending and partially received packets */
 	while (this->packet_queue != nullptr) {
 		delete Packet::PopFromQueue(&this->packet_queue);
 	}
 	delete this->packet_recv;
 	this->packet_recv = nullptr;
+}
+
+/**
+ * Close the actual socket of the connection.
+ * Please make sure CloseConnection is called before CloseSocket, as
+ * otherwise not all resources might be released.
+ */
+void NetworkTCPSocketHandler::CloseSocket()
+{
+	if (this->sock != INVALID_SOCKET) closesocket(this->sock);
+	this->sock = INVALID_SOCKET;
+}
+
+/**
+ * This will put this socket handler in a close state. It will not
+ * actually close the OS socket; use CloseSocket for this.
+ * @param error Whether we quit under an error condition or not.
+ * @return new status of the connection.
+ */
+NetworkRecvStatus NetworkTCPSocketHandler::CloseConnection(bool error)
+{
+	this->MarkClosed();
+	this->writable = false;
+
+	this->EmptyPacketQueue();
 
 	return NETWORK_RECV_STATUS_OKAY;
 }