Function
GioDBusMessageFilterFunction
since: 2.26
Declaration
GDBusMessage*
(* GDBusMessageFilterFunction) (
GDBusConnection* connection,
GDBusMessage* message,
gboolean incoming,
gpointer user_data
)
Description [src]
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.
Available since: 2.26
Parameters
connection-
Type:
GDBusConnectionA
GDBusConnection.The data is owned by the caller of the function. message-
Type:
GDBusMessageA locked
GDBusMessagethat the filter function takes ownership of.The called function takes ownership of the data, and is responsible for freeing it. incoming-
Type:
gbooleanTRUEif it is a message received from the other peer,FALSEif it is a message to be sent to the other peer. user_data-
Type:
gpointerUser data passed when adding the filter.
The argument can be NULL.The data is owned by the caller of the function.
Return value
Type: GDBusMessage
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.
| The caller of the function takes ownership of the data, and is responsible for freeing it. |
The return value can be NULL. |