Package ch.bailu.gtk.gio

Interface DBusConnection.OnDBusMessageFilterFunction

Enclosing class:
DBusConnection
Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public static interface DBusConnection.OnDBusMessageFilterFunction

  • Method Details

    • onDBusMessageFilterFunction

      DBusMessage onDBusMessageFilterFunction(CallbackHandler __self, @Nonnull DBusConnection connection, @Nonnull DBusMessage message, boolean incoming, @Nullable Pointer user_data)
      Signature for function used in g_dbus_connection_add_filter().

      A filter function is passed a #GDBusMessage and expected to return
      a #GDBusMessage too. Passive filter functions that don't modify the
      message can simply return the @message object: 
       static GDBusMessage *
 passive_filter (GDBusConnection *connection
                 GDBusMessage    *message,
                 gboolean         incoming,
                 gpointer         user_data)
 {
   // inspect @message
   return message;
 }

      Filter functions that wants to drop a message can simply return %NULL: 
       static GDBusMessage *
 drop_filter (GDBusConnection *connection
              GDBusMessage    *message,
              gboolean         incoming,
              gpointer         user_data)
 {
   if (should_drop_message)
     {
       g_object_unref (message);
       message = NULL;
     }
   return message;
 }

      Finally, a filter function may modify a message by copying it: 
       static GDBusMessage *
 modifying_filter (GDBusConnection *connection
                   GDBusMessage    *message,
                   gboolean         incoming,
                   gpointer         user_data)
 {
   GDBusMessage *copy;
   GError *error;
 
   error = NULL;
   copy = g_dbus_message_copy (message, &error);
   // handle @error being set
   g_object_unref (message);
 
   // modify @copy
 
   return copy;
 }

      If the returned #GDBusMessage is different from @message and cannot
      be sent on @connection (it could use features, such as file
      descriptors, not compatible with @connection), then a warning is
      logged to standard error. Applications can
      check this ahead of time using g_dbus_message_to_blob() passing a
      #GDBusCapabilityFlags value obtained from @connection.
      Parameters:
      connection - A #GDBusConnection.
      message - A locked #GDBusMessage that the filter function takes ownership of.
      incoming - %TRUE if it is a message received from the other peer, %FALSE if it is a message to be sent to the other peer.
      user_data - User data passed when adding the filter.
      Returns:
      A #GDBusMessage that will be freed with g_object_unref() or %NULL to drop the message. Passive filter functions can simply return the passed @message object.