gdp: Hide the GstStructure in GstEvent

Hide the GstStructure of the event in the implementation specific part so that
we can change it.
Add methods to check and make the event writable.
Add a new method to get a writable GstStructure of the element.
Avoid directly accising the event structure.

diff --git a/gst/gdp/dataprotocol.c b/gst/gdp/dataprotocol.c
index 728b3f5..b1cda55 100644 (file)
--- a/gst/gdp/dataprotocol.c
+++ b/gst/gdp/dataprotocol.c
@@ -394,6 +394,7 @@ gst_dp_packet_from_event_1_0 (const GstEvent * event, GstDPHeaderFlag flags,
   guint8 *h;
   guint32 pl_length;            /* length of payload */
   guchar *string = NULL;
+  const GstStructure *structure;
 
   g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
   g_return_val_if_fail (length, FALSE);
@@ -403,8 +404,9 @@ gst_dp_packet_from_event_1_0 (const GstEvent * event, GstDPHeaderFlag flags,
   *length = GST_DP_HEADER_LENGTH;
   h = g_malloc0 (GST_DP_HEADER_LENGTH);
 
-  if (event->structure) {
-    string = (guchar *) gst_structure_to_string (event->structure);
+  structure = gst_event_get_structure ((GstEvent *) event);
+  if (structure) {
+    string = (guchar *) gst_structure_to_string (structure);
     GST_LOG ("event %p has structure, string %s", event, string);
     pl_length = strlen ((gchar *) string) + 1;  /* include trailing 0 */
   } else {