Module: Gio::AsyncInitable
- Defined in:
- (unknown)
Overview
This is the asynchronous version of #GInitable; 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 GAsync::Initable 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 g_async_initable_new_async() directly, or indirectly via a foo_thing_new_async() wrapper. This will call g_async_initable_init_async() under the cover, calling back with nil 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;
}
Instance Method Summary collapse
- #init_async(initable, io_priority, cancellable, callback, user_data) ⇒ nil
-
#init_finish(initable, res) ⇒ TrueClass
will return false and set error appropriately if present.
-
#new_finish(res) ⇒ GObject::Object
Finishes the async construction for the various g_async_initable_new calls, returning the created object or nil on error.
Instance Method Details
#init_async(initable, io_priority, cancellable, callback, user_data) ⇒ nil
#init_finish(initable, res) ⇒ TrueClass
will return false and set error appropriately if present.
#new_finish(res) ⇒ GObject::Object
Finishes the async construction for the various g_async_initable_new calls, returning the created object or nil on error.