Bug 1440 - Add clutter_get_current_event_time()

The clutter_get_current_event_time() is a global function for
retrieving the timestamp of the current event being propagated
by Clutter. Such function avoids the need to propagate the
timestamp from within user code.

clutter/clutter-event.c

@@ -529,3 +529,25 @@ clutter_events_pending (void)
   return g_queue_is_empty (context->events_queue) == FALSE;
 }
 
+/**
+ * clutter_get_current_event_time:
+ *
+ * Retrieves the timestamp of the last event, if there is an
+ * event or if the event has a timestamp.
+ *
+ * Return value: the event timestamp, or %CLUTTER_CURRENT_TIME
+ *
+ * Since: 1.0
+ */
+guint32
+clutter_get_current_event_time (void)
+{
+  ClutterMainContext *context = clutter_context_get_default ();
+
+  g_return_val_if_fail (context != NULL, FALSE);
+
+  if (context->last_event_time != 0)
+    return context->last_event_time;
+
+  return CLUTTER_CURRENT_TIME;
+}

clutter/clutter-event.h

@@ -466,6 +466,8 @@ guint32             clutter_keysym_to_unicode   (guint               keyval);
 
 ClutterStage*       clutter_event_get_stage     (ClutterEvent       *event);
 
+guint32             clutter_get_current_event_time (void);
+
 G_END_DECLS
 
 #endif /* __CLUTTER_EVENT_H__ */

clutter/clutter-main.c

@@ -1957,6 +1957,8 @@ clutter_do_event (ClutterEvent *event)
 
   CLUTTER_TIMESTAMP (EVENT, "Event received");
 
+  context->last_event_time = clutter_event_get_time (event);
+
   switch (event->type)
     {
       case CLUTTER_NOTHING:

clutter/clutter-private.h

@@ -131,6 +131,8 @@ struct _ClutterMainContext
 
   GSList              *input_devices;   /* For extra input devices, i.e
                                            MultiTouch */
+
+  guint32 last_event_time;
 };
 
 #define CLUTTER_CONTEXT()	(clutter_context_get_default ())