AsyncInitable
GAsyncInitable is an interface for asynchronously initializable objects.
This is the asynchronous version of iface@Gio.Initable; it behaves the same in all ways except that initialization is asynchronous. For more details see the descriptions on GInitable.
A class may implement both the GInitable and GAsyncInitable interfaces.
Users of objects implementing this are not intended to use the interface method directly; instead it will be used automatically in various ways. For C applications you generally just call func@Gio.AsyncInitable.new_async directly, or indirectly via a foo_thing_new_async() wrapper. This will call method@Gio.AsyncInitable.init_async under the covers, calling back with NULL and a set GError on failure.
A typical implementation might look something like this:
enum {
NOT_INITIALIZED,
INITIALIZING,
INITIALIZED
};
static void
_foo_ready_cb (Foo *self)
{
GList *l;
self->priv->state = INITIALIZED;
for (l = self->priv->init_results; l != NULL; l = l->next)
{
GTask *task = l->data;
if (self->priv->success)
g_task_return_boolean (task, TRUE);
else
g_task_return_new_error (task, ...);
g_object_unref (task);
}
g_list_free (self->priv->init_results);
self->priv->init_results = NULL;
}
static void
foo_init_async (GAsyncInitable *initable,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
Foo *self = FOO (initable);
GTask *task;
task = g_task_new (initable, cancellable, callback, user_data);
g_task_set_name (task, G_STRFUNC);
switch (self->priv->state)
{
case NOT_INITIALIZED:
_foo_get_ready (self);
self->priv->init_results = g_list_append (self->priv->init_results,
task);
self->priv->state = INITIALIZING;
break;
case INITIALIZING:
self->priv->init_results = g_list_append (self->priv->init_results,
task);
break;
case INITIALIZED:
if (!self->priv->success)
g_task_return_new_error (task, ...);
else
g_task_return_boolean (task, TRUE);
g_object_unref (task);
break;
}
}
static gboolean
foo_init_finish (GAsyncInitable *initable,
GAsyncResult *result,
GError **error)
{
g_return_val_if_fail (g_task_is_valid (result, initable), FALSE);
return g_task_propagate_boolean (G_TASK (result), error);
}
static void
foo_async_initable_iface_init (gpointer g_iface,
gpointer data)
{
GAsyncInitableIface *iface = g_iface;
iface->init_async = foo_init_async;
iface->init_finish = foo_init_finish;
}Since
2.22
Inheritors
Functions
Starts asynchronous initialization of the object implementing the interface. This must be done before any real use of the object after initial construction. If the object also implements #GInitable you can optionally call g_initable_init() instead.
Finishes asynchronous initialization and returns the result. See g_async_initable_init_async().
Finishes the async construction for the various g_async_initable_new calls, returning the created object or null on error.