event-widget: add convenient API to query dates

Simply it is faster not to allocate memory when there is no need of it

src/gcal-event-widget.c

@@ -910,6 +910,23 @@ gcal_event_widget_get_date (GcalEventWidget *event)
   return dt;
 }
 
+/**
+ * gcal_event_widget_peek_start_date:
+ * @event:
+ *
+ * Return the starting date of the event.
+ *
+ * Returns: (Transfer none): An {@link icaltimetype} instance
+ **/
+const icaltimetype*
+gcal_event_widget_peek_start_date (GcalEventWidget *event)
+{
+  GcalEventWidgetPrivate *priv;
+  priv = gcal_event_widget_get_instance_private (event);
+
+  return priv->dt_start;
+}
+
 /**
  * gcal_event_widget_set_end_date:
  * @event: a #GcalEventWidget
@@ -942,6 +959,23 @@ gcal_event_widget_get_end_date (GcalEventWidget *event)
   return dt;
 }
 
+/**
+ * gcal_event_widget_peek_end_date:
+ * @event:
+ *
+ * Return the end date of the event.
+ *
+ * Returns: (Transfer none): An {@link icaltimetype} instance
+ **/
+const icaltimetype*
+gcal_event_widget_peek_end_date (GcalEventWidget *event)
+{
+  GcalEventWidgetPrivate *priv;
+  priv = gcal_event_widget_get_instance_private (event);
+
+  return priv->dt_end;
+}
+
 void
 gcal_event_widget_set_summary (GcalEventWidget *event,
                                gchar           *summary)

src/gcal-event-widget.h

@@ -75,11 +75,15 @@ void          gcal_event_widget_set_date                   (GcalEventWidget    *
 
 icaltimetype* gcal_event_widget_get_date                   (GcalEventWidget    *event);
 
+const icaltimetype* gcal_event_widget_peek_start_date            (GcalEventWidget    *event);
+
 void          gcal_event_widget_set_end_date               (GcalEventWidget    *event,
                                                             const icaltimetype *date);
 
 icaltimetype* gcal_event_widget_get_end_date               (GcalEventWidget    *event);
 
+const icaltimetype* gcal_event_widget_peek_end_date              (GcalEventWidget    *event);
+
 void          gcal_event_widget_set_summary                (GcalEventWidget    *event,
                                                             gchar              *summary);