[Path] Make object paths stable across restarts

Fix issue #114: <https://github.com/01org/dleyna-renderer/issues/114>

Root paths for servers were builded using an incremental counter,
based of the discovery order made by GSSDP:

Results were of this form:

/com/intel/dLeynaRenderer/server/0
/com/intel/dLeynaRenderer/server/1

Object paths were builded on these root paths:

/com/intel/dLeynaRenderer/server/0/xxxxxxxxxx

There is no persistence between restarts of dleyna because we can't
assign the same index to the same server.

To fix this issue, we replace the volatile part of the root path, id the index,
by a non volatile and unique part, id the server udn.

The server udn is a string of this form: "uuid:<uuid string>"
<uuid string> is defined by RFC 4122(<http://www.ietf.org/rfc/rfc4122.txt>
and it's composed only with hex digit and char '-'

To make the path compatible with dbus and 'reversible':
1 - remove the prefix 'uuid:'
2 - convert '-' char to '_' char

Result is of the form below:

/com/intel/dLeynaRenderer/server/99951d71_23d5_5525_94eb_a4aa78a98211

This path is stable accross dleyna restart and identify uniquely a
server. This can be sued to save object path and to use them after
multiple restart of the server and dLeyna.

Signed-off-by: Ludovic Ferrandis <ludovic.ferrandis@intel.com>

3 files changed, 12 insertions, 9 deletions

diff --git a/libdleyna/renderer/device.c b/libdleyna/renderer/device.c
index d5aa82c..f2766e1 100644
--- a/libdleyna/renderer/device.c
+++ b/libdleyna/renderer/device.c
@@ -820,18 +820,26 @@ dlr_device_t *dlr_device_new(
 			dleyna_connector_id_t connection,
 			GUPnPDeviceProxy *proxy,
 			const gchar *ip_address,
-			guint counter,
+			const char *udn,
 			const dleyna_connector_dispatch_cb_t *dispatch_table,
 			const dleyna_task_queue_key_t *queue_id)
 {
 	dlr_device_t *dev;
 	gchar *new_path;
+	gchar *uuid;
 	dlr_device_context_t *context;
 
 	DLEYNA_LOG_DEBUG("New Device on %s", ip_address);
 
-	new_path = g_strdup_printf("%s/%u", DLEYNA_SERVER_PATH, counter);
+	/* Strip 'uuid:' string prefix if exists and replace unauthorized
+	 * dbus path char from uuid string */
+	uuid = strchr(udn, ':');
+	uuid = g_strdup(uuid ? uuid + 1 : udn);
+	uuid = g_strdelimit(uuid, "-", '_');
+
+	new_path = g_strdup_printf("%s/%s", DLEYNA_SERVER_PATH, uuid);
 	DLEYNA_LOG_DEBUG("Server Path %s", new_path);
+	g_free(uuid);
 
 	dev = g_new0(dlr_device_t, 1);
 
diff --git a/libdleyna/renderer/device.h b/libdleyna/renderer/device.h
index 70692f3..dd39081 100644
--- a/libdleyna/renderer/device.h
+++ b/libdleyna/renderer/device.h
@@ -101,7 +101,7 @@ dlr_device_t *dlr_device_new(
 			dleyna_connector_id_t connection,
 			GUPnPDeviceProxy *proxy,
 			const gchar *ip_address,
-			guint counter,
+			const char *udn,
 			const dleyna_connector_dispatch_cb_t *dispatch_table,
 			const dleyna_task_queue_key_t *queue_id);
 
diff --git a/libdleyna/renderer/upnp.c b/libdleyna/renderer/upnp.c
index fefc340..bd9a688 100644
--- a/libdleyna/renderer/upnp.c
+++ b/libdleyna/renderer/upnp.c
@@ -45,7 +45,6 @@ struct dlr_upnp_t_ {
 	void *user_data;
 	GHashTable *server_udn_map;
 	GHashTable *server_uc_map;
-	guint counter;
 	dlr_host_service_t *host_service;
 };
 
@@ -186,14 +185,10 @@ static void prv_server_available_cb(GUPnPControlPoint *cp,
 		queue_id = prv_create_device_queue(&priv_t);
 
 		device = dlr_device_new(upnp->connection, proxy, ip_address,
-					upnp->counter,
-					upnp->interface_info,
-					queue_id);
+					udn, upnp->interface_info, queue_id);
 
 		prv_update_device_context(priv_t, upnp, udn, device, ip_address,
 					  queue_id);
-
-		upnp->counter++;
 	} else {
 		DLEYNA_LOG_DEBUG("Device Found");