Addition of the structure for the read write query splitter routing module. This is

in a seperate directory to the others as it is likely to be a complex routing module.

modules/routing/readwritesplit/router.c

@@ -0,0 +1,160 @@
+/*
+ * This file is distributed as part of the SkySQL Gateway.  It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright SkySQL Ab 2013
+ */
+#include <stdio.h>
+#include <router.h>
+
+/**
+ * @file router.c	The entry points for the read/write query splitting
+ * router module.
+ *
+ * This file contains the entry points that comprise the API to the read write
+ * query splitting router.
+ *
+ */
+static char *version_str = "V1.0.0";
+
+static	ROUTER	*createInstance(SERVICE *service, char **options);
+static	void	*newSession(ROUTER *instance, SESSION *session);
+static	void 	closeSession(ROUTER *instance, void *session);
+static	int	routeQuery(ROUTER *instance, void *session, GWBUF *queue);
+static	void	diagnostic(ROUTER *instance, DCB *dcb);
+
+static ROUTER_OBJECT MyObject = { createInstance, newSession, closeSession, routeQuery, diagnostic };
+
+/**
+ * Implementation of the mandatory version entry point
+ *
+ * @return version string of the module
+ */
+char *
+version()
+{
+	return version_str;
+}
+
+/**
+ * The module initialisation routine, called when the module
+ * is first loaded.
+ */
+void
+ModuleInit()
+{
+	fprintf(stderr, "Initialse read/writer splitting query router module.\n");
+}
+
+/**
+ * The module entry point routine. It is this routine that
+ * must populate the structure that is referred to as the
+ * "module object", this is a structure with the set of
+ * external entry points for this module.
+ *
+ * @return The module object
+ */
+ROUTER_OBJECT *
+GetModuleObject()
+{
+	fprintf(stderr, "Returing test router module object.\n");
+	return &MyObject;
+}
+
+/**
+ * Create an instance of the router for a particular service
+ * within the gateway.
+ *
+ * The job of ths entry point is to create the service wide data needed
+ * for the query router. This is information needed to route queries that
+ * is not related to any individual client session, exmaples of data that
+ * might be stored in the ROUTER object for a particular query router are
+ * connections counts, last used connection etc so that balancing may
+ * take place.
+ * 
+ * @param service	The service this router is being create for
+ * @param options	The options for this query router
+ *
+ * @return The instance data for this new instance
+ */
+static	ROUTER	*
+createInstance(SERVICE *service, char **options)
+{
+	return NULL;
+}
+
+/**
+ * Associate a new session with this instance of the router.
+ *
+ * The session is used to store all the data required for a particular
+ * client connection.
+ *
+ * @param instance	The router instance data
+ * @param session	The session itself
+ * @return Session specific data for this session
+ */
+static	void	*
+newSession(ROUTER *instance, SESSION *session)
+{
+	return NULL;
+}
+
+/**
+ * Close a session with the router, this is the mechanism
+ * by which a router may cleanup data structure etc.
+ *
+ * @param instance	The router instance data
+ * @param session	The session being closed
+ */
+static	void 	
+closeSession(ROUTER *instance, void *session)
+{
+}
+
+
+/**
+ * The main routing entry, this is called with every packet that is
+ * received and has to be forwarded to the backend database.
+ *
+ * The routeQuery will make the routing decision based on the contents
+ * of the instance, session and the query itself in the queue. The
+ * data in the queue may not represent a complete query, it represents
+ * the data that has been received. The query router itself is responsible
+ * for buffering the partial query, a later call to the query router will
+ * contain the remainder, or part thereof of the query.
+ *
+ * @param instance	The query router instance
+ * @param session	The session assoicated with the client
+ * @param queue		Gateway buffer queue with the packets received
+ *
+ * @return The number of queries forwarded
+ */
+static	int	
+routeQuery(ROUTER *instance, void *session, GWBUF *queue)
+{
+	return 0;
+}
+
+/**
+ * Diagnostics routine
+ *
+ * Print query router statistics to the DCB passed in
+ *
+ * @param	instance	The router instance
+ * @param	dcb		The DCB for diagnostic output
+ */
+static	void
+diagnostic(ROUTER *instance, DCB *dcb)
+{
+}