tools: print "pad-added", "pad-removed" and "no-more-pads" signals for elements with...

It's often not obvious to people that elements like e.g. uridecodebin
(or demuxers) automatically support the standard signals of the
GstElement class, so let's print the useful pad-related ones for
elements with sometimes pads.

diff --git a/tools/gst-inspect.c b/tools/gst-inspect.c
index a43e8ac..c86285e 100644 (file)
--- a/tools/gst-inspect.c
+++ b/tools/gst-inspect.c
@@ -880,13 +880,19 @@ print_pad_info (GstElement * element)
   }
 }
 
-#if 0
-static gint
-compare_signal_names (GSignalQuery * a, GSignalQuery * b)
+static gboolean
+has_sometimes_template (GstElement * element)
 {
-  return strcmp (a->signal_name, b->signal_name);
+  GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
+  GList *l;
+
+  for (l = klass->padtemplates; l != NULL; l = l->next) {
+    if (GST_PAD_TEMPLATE (l->data)->presence == GST_PAD_SOMETIMES)
+      return TRUE;
+  }
+
+  return FALSE;
 }
-#endif
 
 static void
 print_signal_info (GstElement * element)
@@ -901,6 +907,22 @@ print_signal_info (GstElement * element)
 
   for (k = 0; k < 2; k++) {
     found_signals = NULL;
+
+    /* For elements that have sometimes pads, also list a few useful GstElement
+     * signals. Put these first, so element-specific ones come later. */
+    if (k == 0 && has_sometimes_template (element)) {
+      query = g_new0 (GSignalQuery, 1);
+      g_signal_query (g_signal_lookup ("pad-added", GST_TYPE_ELEMENT), query);
+      found_signals = g_slist_append (found_signals, query);
+      query = g_new0 (GSignalQuery, 1);
+      g_signal_query (g_signal_lookup ("pad-removed", GST_TYPE_ELEMENT), query);
+      found_signals = g_slist_append (found_signals, query);
+      query = g_new0 (GSignalQuery, 1);
+      g_signal_query (g_signal_lookup ("no-more-pads", GST_TYPE_ELEMENT),
+          query);
+      found_signals = g_slist_append (found_signals, query);
+    }
+
     for (type = G_OBJECT_TYPE (element); type; type = g_type_parent (type)) {
       if (type == GST_TYPE_ELEMENT || type == GST_TYPE_OBJECT)
         break;