Allow to detect which node gave current configuration

This feature used in libcouchbase to judge about healthness of REST
connection.

Change-Id: Ie6370ca2d6e7313228965870d70d419e6b79a0f5
Reviewed-on: http://review.couchbase.org/30833
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>

include/libvbucket/vbucket.h

@@ -254,6 +254,14 @@ extern "C" {
     LIBVBUCKET_PUBLIC_API
     const char *vbucket_config_get_rest_api_server(VBUCKET_CONFIG_HANDLE vb, int i);
 
+    /**
+     * Check if the server was used for configuration
+     *
+     * @return non-zero for configuration node
+     */
+    LIBVBUCKET_PUBLIC_API
+    int vbucket_config_is_config_node(VBUCKET_CONFIG_HANDLE h, int i);
+
     /**
      * Get the distribution type. Currently can be or "vbucket" (for
      * eventually persisted nodes) either "ketama" (for plain memcached

src/vbucket.c

@@ -36,6 +36,8 @@ struct server_st {
     char *authority;        /* host:port */
     char *rest_api_authority;
     char *couchdb_api_base;
+    int config_node;        /* non-zero if server struct describes node,
+                               which is listening */
 };
 
 struct vbucket_st {
@@ -253,6 +255,10 @@ static int update_server_info(struct vbucket_config_st *vb, cJSON *config) {
                     }
                     vb->servers[idx].rest_api_authority = value;
                 }
+                json = cJSON_GetObjectItem(node, "thisNode");
+                if (json != NULL && json->type == cJSON_True) {
+                    vb->servers[idx].config_node = 1;
+                }
             }
         }
     }
@@ -672,6 +678,10 @@ const char *vbucket_config_get_rest_api_server(VBUCKET_CONFIG_HANDLE vb, int i)
     return vb->servers[i].rest_api_authority;
 }
 
+int vbucket_config_is_config_node(VBUCKET_CONFIG_HANDLE vb, int i) {
+    return vb->servers[i].config_node;
+}
+
 VBUCKET_DISTRIBUTION_TYPE vbucket_config_get_distribution_type(VBUCKET_CONFIG_HANDLE vb) {
     return vb->distribution;
 }