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.
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.
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.