MXS-1725 Replace macros with function

The macros MXS_SESSION_ROUTE_QUERY and MXS_SESSION_ROUTE_REPLY
are now defined in terms of functions that do the actual stuff.

Incidentally, the function session_route_reply() existed already
but was not used. Now slightly rewritten so that it does not simply
ignore misuse.

include/maxscale/session.h

@@ -198,22 +198,42 @@ typedef struct session
     skygw_chk_t             ses_chk_tail;
 } MXS_SESSION;
 
+
+/**
+ * Function to be used by protocol module for routing incoming data
+ * to the first component in the pipeline of filters and a router.
+ *
+ * @param session  The session.
+ * @param buffer   A buffer.
+ *
+ * @return True, if the routing should continue, false otherwise.
+ */
+bool session_route_query(MXS_SESSION *session, GWBUF *buffer);
+
+/**
+ * Function to be used by the router module to route the replies to
+ * the first element in the pipeline of filters and a protocol.
+ *
+ * @param session  The session.
+ * @param buffer   A buffer.
+ *
+ * @return True, if the routing should continue, false otherwise.
+ */
+bool session_route_reply(MXS_SESSION *session, GWBUF *buffer);
+
 /**
  * A convenience macro that can be used by the protocol modules to route
  * the incoming data to the first element in the pipeline of filters and
  * routers.
  */
-#define MXS_SESSION_ROUTE_QUERY(sess, buf)                          \
-    ((sess)->head.routeQuery)((sess)->head.instance,            \
-                              (sess)->head.session, (buf))
+#define MXS_SESSION_ROUTE_QUERY(sess, buf) session_route_query(sess, buf)
+
 /**
  * A convenience macro that can be used by the router modules to route
  * the replies to the first element in the pipeline of filters and
  * the protocol.
  */
-#define MXS_SESSION_ROUTE_REPLY(sess, buf)                          \
-    ((sess)->tail.clientReply)((sess)->tail.instance,           \
-                               (sess)->tail.session, (buf))
+#define MXS_SESSION_ROUTE_REPLY(sess, buf) session_route_reply(sess, buf)
 
 /**
  * Allocate a new session for a new client of the specified service.

server/core/session.cc

@@ -702,30 +702,47 @@ session_get_remote(const MXS_SESSION *session)
     return NULL;
 }
 
-bool session_route_query(MXS_SESSION* ses, GWBUF* buf)
+bool session_route_query(MXS_SESSION* session, GWBUF* buffer)
 {
-    bool succp;
+    ss_dassert(session);
+    ss_dassert(session->head.routeQuery);
+    ss_dassert(session->head.instance);
+    ss_dassert(session->head.session);
 
-    if (ses->head.routeQuery == NULL ||
-        ses->head.instance == NULL ||
-        ses->head.session == NULL)
-    {
-        succp = false;
-        goto return_succp;
-    }
+    bool rv;
 
-    if (ses->head.routeQuery(ses->head.instance, ses->head.session, buf) == 1)
+    if (session->head.routeQuery(session->head.instance, session->head.session, buffer) == 1)
     {
-        succp = true;
+        rv = true;
     }
     else
     {
-        succp = false;
+        rv = false;
     }
-return_succp:
-    return succp;
+
+    return rv;
 }
 
+bool session_route_reply(MXS_SESSION *session, GWBUF *buffer)
+{
+    ss_dassert(session);
+    ss_dassert(session->tail.clientReply);
+    ss_dassert(session->tail.instance);
+    ss_dassert(session->tail.session);
+
+    bool rv;
+
+    if (session->tail.clientReply(session->tail.instance, session->tail.session, buffer) == 1)
+    {
+        rv = true;
+    }
+    else
+    {
+        rv = false;
+    }
+
+    return rv;
+}
 
 /**
  * Return the username of the user connected to the client side of the