AsyncInitable


Object Hierarchy:

Object hierarchy for AsyncInitable

Description:

[ Version ( since = "2.22" ) ]
public interface AsyncInitable : Object

This is the asynchronous version of Initable; it behaves the same in all ways except that initialization is asynchronous.

For more details see the descriptions on Initable.

A class may implement both the Initable and AsyncInitable 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 new_async directly, or indirectly via a foo_thing_new_async wrapper. This will call init_async under the cover, 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);

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;
}

All known implementing classes:

Namespace: GLib
Package: gio-2.0

Content:

Static methods:

Methods:

Inherited Members: