- Added _LOCKED_STATE element flag

Original commit message from CVS:
- Added _LOCKED_STATE element flag
- parent bin does not perform state changes on _LOCKED_STATE elements

gst/gstbin.c

@@ -431,6 +431,12 @@ gst_bin_add_func (GstBin *bin, GstElement *element)
   GstElementState state;
   GstScheduler *sched;
 
+  /* the element must not already have a parent */
+  g_return_if_fail (GST_ELEMENT_PARENT (element) == NULL);
+
+  /* must be not be in PLAYING state in order to modify bin */
+  g_return_if_fail (GST_STATE (bin) != GST_STATE_PLAYING);
+
   /* then check to see if the element's name is already taken in the bin */
   if (gst_object_check_uniqueness (bin->children, 
 	                           GST_ELEMENT_NAME (element)) == FALSE)
@@ -485,12 +491,6 @@ gst_bin_add (GstBin *bin, GstElement *element)
   GST_DEBUG (GST_CAT_PARENTAGE, "adding element \"%s\" to bin \"%s\"",
 	     GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
 
-  /* the element must not already have a parent */
-  g_return_if_fail (GST_ELEMENT_PARENT (element) == NULL);
-
-  /* must be not be in PLAYING state in order to modify bin */
-  g_return_if_fail (GST_STATE (bin) != GST_STATE_PLAYING);
-
   bclass = GST_BIN_GET_CLASS (bin);
 
   if (bclass->add_element) {
@@ -694,6 +694,9 @@ gst_bin_change_state (GstElement * element)
     child = GST_ELEMENT (children->data);
     children = g_list_next (children);
 
+    if (GST_FLAG_IS_SET (child, GST_ELEMENT_LOCKED_STATE))
+      continue;
+
     old_child_state = GST_STATE (child);
 
     switch (gst_element_set_state (child, pending)) {

gst/gstelement.h

@@ -108,6 +108,9 @@ typedef enum {
   GST_ELEMENT_SCHEDULER_PRIVATE1,
   GST_ELEMENT_SCHEDULER_PRIVATE2,
 
+  /* ignore state changes from parent */
+  GST_ELEMENT_LOCKED_STATE,
+
   /* use some padding for future expansion */
   GST_ELEMENT_FLAG_LAST		= GST_OBJECT_FLAG_LAST + 16
 } GstElementFlags;
@@ -292,18 +295,20 @@ GList*			gst_element_get_pad_template_list	(GstElement *element);
 GstPadTemplate*		gst_element_get_compatible_pad_template (GstElement *element, GstPadTemplate *compattempl);
 
 gboolean		gst_element_link		(GstElement *src, GstElement *dest);
-gboolean		gst_element_link_many 	(GstElement *element_1, GstElement *element_2, ...);
+gboolean		gst_element_link_many 		(GstElement *element_1, 
+							 GstElement *element_2, ...);
 gboolean		gst_element_link_filtered 	(GstElement *src, GstElement *dest,
 							 GstCaps *filtercaps);
 void			gst_element_unlink 		(GstElement *src, GstElement *dest);
-void			gst_element_unlink_many 	(GstElement *element_1, GstElement *element_2, ...);
+void			gst_element_unlink_many 	(GstElement *element_1, 
+							 GstElement *element_2, ...);
 
-gboolean		gst_element_link_pads	(GstElement *src, const gchar *srcpadname,
+gboolean		gst_element_link_pads		(GstElement *src, const gchar *srcpadname,
 							 GstElement *dest, const gchar *destpadname);
-gboolean		gst_element_link_pads_filtered (GstElement *src, const gchar *srcpadname,
+gboolean		gst_element_link_pads_filtered 	(GstElement *src, const gchar *srcpadname,
 							 GstElement *dest, const gchar *destpadname,
 							 GstCaps *filtercaps);
-void			gst_element_unlink_pads	(GstElement *src, const gchar *srcpadname,
+void			gst_element_unlink_pads		(GstElement *src, const gchar *srcpadname,
 							 GstElement *dest, const gchar *destpadname);
 
 const GstEventMask*	gst_element_get_event_masks	(GstElement *element);