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Add examples for GAsyncInitiable and GSimpleAsyncResult
Bug 602417
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@ -45,6 +45,100 @@
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* directly, or indirectly via a foo_thing_new_async() wrapper. This will call
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* g_async_initable_init_async() under the cover, calling back with %NULL and
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* a set %GError on failure.
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*
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* A typical implementation might look something like this:
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*
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* |[
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* enum {
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* NOT_INITIALIZED,
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* INITIALIZING,
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* INITIALIZED
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* };
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*
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* static void
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* _foo_ready_cb (Foo *self)
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* {
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* GList *l;
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*
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* self->priv->state = INITIALIZED;
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*
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* for (l = self->priv->init_results; l != NULL; l = l->next)
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* {
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* GSimpleAsyncResult *simple = l->data;
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*
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* if (!self->priv->success)
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* g_simple_async_result_set_error (simple, ...);
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*
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* g_simple_async_result_complete (simple);
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* g_object_unref (simple);
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* }
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*
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* g_list_free (self->priv->init_results);
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* self->priv->init_results = NULL;
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* }
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*
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* static void
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* foo_init_async (GAsyncInitable *initable,
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* int io_priority,
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* GCancellable *cancellable,
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* GAsyncReadyCallback callback,
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* gpointer user_data)
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* {
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* Foo *self = FOO (initable);
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* GSimpleAsyncResult *simple;
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*
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* simple = g_simple_async_result_new (G_OBJECT (initable)
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* callback,
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* user_data,
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* foo_init_async);
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*
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* switch (self->priv->state)
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* {
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* case NOT_INITIALIZED:
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* _foo_get_ready (self);
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* self->priv->init_results = g_list_append (self->priv->init_results,
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* simple);
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* self->priv->state = INITIALIZING;
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* break;
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* case INITIALIZING:
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* self->priv->init_results = g_list_append (self->priv->init_results,
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* simple);
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* break;
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* case INITIALIZED:
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* if (!self->priv->success)
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* g_simple_async_result_set_error (simple, ...);
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*
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* g_simple_async_result_complete_in_idle (simple);
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* g_object_unref (simple);
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* break;
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* }
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* }
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*
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* static gboolean
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* foo_init_finish (GAsyncInitable *initable,
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* GAsyncResult *result,
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* GError **error)
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* {
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* g_return_val_if_fail (g_simple_async_result_is_valid (result,
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* G_OBJECT (initable), foo_init_async), FALSE);
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*
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* if (g_simple_async_result_propagate_error (G_SIMPLE_ASYNC_RESULT (result),
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* error))
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* return FALSE;
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*
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* return TRUE;
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* }
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*
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* static void
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* foo_async_initable_iface_init (gpointer g_iface,
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* gpointer data)
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* {
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* GAsyncInitableIface *iface = g_iface;
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*
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* iface->init_async = foo_init_async;
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* iface->init_finish = foo_init_finish;
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* }
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* ]|
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*/
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static void g_async_initable_real_init_async (GAsyncInitable *initable,
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@ -109,7 +109,109 @@
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* g_simple_async_result_get_op_res_gssize() are
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* provided, getting the operation's result as a gpointer, gboolean, and
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* gssize, respectively.
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**/
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*
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* For the details of the requirements implementations must respect, see
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* #GAsyncResult. A typical implementation of an asynchronous operation
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* using GSimpleAsyncResult looks something like this:
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*
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* |[
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* static void
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* baked_cb (Cake *cake,
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* gpointer user_data)
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* {
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* /* In this example, this callback is not given a reference to the cake, so
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* * the GSimpleAsyncResult has to take a reference to it.
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* */
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* GSimpleAsyncResult *result = user_data;
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*
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* if (cake == NULL)
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* g_simple_async_result_set_error (result,
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* BAKER_ERRORS,
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* BAKER_ERROR_NO_FLOUR,
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* "Go to the supermarket");
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* else
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* g_simple_async_result_set_op_res_gpointer (result,
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* g_object_ref (cake),
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* g_object_unref);
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*
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*
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* /* In this example, we assume that baked_cb is called as a callback from
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* * the mainloop, so it's safe to complete the operation synchronously here.
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* * If, however, _baker_prepare_cake () might call its callback without
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* * first returning to the mainloop — inadvisable, but some APIs do so —
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* * we would need to use g_simple_async_result_complete_in_idle().
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* */
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* g_simple_async_result_complete (result);
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* g_object_unref (result);
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* }
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*
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* void
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* baker_bake_cake_async (Baker *self,
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* guint radius,
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* GAsyncReadyCallback callback,
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* gpointer user_data)
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* {
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* GSimpleAsyncResult *simple;
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* Cake *cake;
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*
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* if (radius < 3)
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* {
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* g_simple_async_report_error_in_idle (G_OBJECT (self),
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* callback,
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* user_data,
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* BAKER_ERRORS,
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* BAKER_ERROR_TOO_SMALL,
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* "%ucm radius cakes are silly",
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* radius);
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* return;
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* }
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*
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* simple = g_simple_async_result_new (G_OBJECT (self),
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* callback,
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* user_data,
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* baker_bake_cake_async);
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* cake = _baker_get_cached_cake (self, radius);
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*
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* if (cake != NULL)
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* {
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* g_simple_async_result_set_op_res_gpointer (simple,
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* g_object_ref (cake),
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* g_object_unref);
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* g_simple_async_result_complete_in_idle (simple);
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* g_object_unref (simple);
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* /* Drop the reference returned by _baker_get_cached_cake(); the
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* * GSimpleAsyncResult has taken its own reference.
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* */
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* g_object_unref (cake);
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* return;
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* }
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*
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* _baker_prepare_cake (self, radius, baked_cb, user_data);
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* }
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*
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* Cake *
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* baker_bake_cake_finish (Baker *self,
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* GAsyncResult *result,
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* GError **error)
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* {
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* GSimpleAsyncResult *simple;
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* Cake *cake;
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*
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* g_return_val_if_fail (g_simple_async_result_is_valid (result,
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* G_OBJECT (self),
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* baker_bake_cake_async),
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* NULL);
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*
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* simple = (GSimpleAsyncResult *) result;
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*
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* if (g_simple_async_result_propagate_error (simple, error))
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* return NULL;
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*
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* cake = CAKE (g_simple_async_result_get_op_res_gpointer (simple));
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* return g_object_ref (cake);
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* }
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* ]|
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*/
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static void g_simple_async_result_async_result_iface_init (GAsyncResultIface *iface);
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