Commit 28a4fff7 authored by Will Thompson's avatar Will Thompson 🌓 Committed by Matthias Clasen

Add examples for GAsyncInitiable and GSimpleAsyncResult

Bug 602417
parent 7a32e34f
......@@ -45,6 +45,100 @@
* directly, or indirectly via a foo_thing_new_async() wrapper. This will call
* g_async_initable_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)
* {
* GSimpleAsyncResult *simple = l->data;
*
* if (!self->priv->success)
* g_simple_async_result_set_error (simple, ...);
*
* g_simple_async_result_complete (simple);
* g_object_unref (simple);
* }
*
* 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);
* GSimpleAsyncResult *simple;
*
* simple = g_simple_async_result_new (G_OBJECT (initable)
* callback,
* user_data,
* foo_init_async);
*
* switch (self->priv->state)
* {
* case NOT_INITIALIZED:
* _foo_get_ready (self);
* self->priv->init_results = g_list_append (self->priv->init_results,
* simple);
* self->priv->state = INITIALIZING;
* break;
* case INITIALIZING:
* self->priv->init_results = g_list_append (self->priv->init_results,
* simple);
* break;
* case INITIALIZED:
* if (!self->priv->success)
* g_simple_async_result_set_error (simple, ...);
*
* g_simple_async_result_complete_in_idle (simple);
* g_object_unref (simple);
* break;
* }
* }
*
* static gboolean
* foo_init_finish (GAsyncInitable *initable,
* GAsyncResult *result,
* GError **error)
* {
* g_return_val_if_fail (g_simple_async_result_is_valid (result,
* G_OBJECT (initable), foo_init_async), FALSE);
*
* if (g_simple_async_result_propagate_error (G_SIMPLE_ASYNC_RESULT (result),
* error))
* return FALSE;
*
* return TRUE;
* }
*
* 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;
* }
* ]|
*/
static void g_async_initable_real_init_async (GAsyncInitable *initable,
......
......@@ -109,7 +109,109 @@
* g_simple_async_result_get_op_res_gssize() are
* provided, getting the operation's result as a gpointer, gboolean, and
* gssize, respectively.
**/
*
* For the details of the requirements implementations must respect, see
* #GAsyncResult. A typical implementation of an asynchronous operation
* using GSimpleAsyncResult looks something like this:
*
* |[
* static void
* baked_cb (Cake *cake,
* gpointer user_data)
* {
* /* In this example, this callback is not given a reference to the cake, so
* * the GSimpleAsyncResult has to take a reference to it.
* */
* GSimpleAsyncResult *result = user_data;
*
* if (cake == NULL)
* g_simple_async_result_set_error (result,
* BAKER_ERRORS,
* BAKER_ERROR_NO_FLOUR,
* "Go to the supermarket");
* else
* g_simple_async_result_set_op_res_gpointer (result,
* g_object_ref (cake),
* g_object_unref);
*
*
* /* In this example, we assume that baked_cb is called as a callback from
* * the mainloop, so it's safe to complete the operation synchronously here.
* * If, however, _baker_prepare_cake () might call its callback without
* * first returning to the mainloop — inadvisable, but some APIs do so —
* * we would need to use g_simple_async_result_complete_in_idle().
* */
* g_simple_async_result_complete (result);
* g_object_unref (result);
* }
*
* void
* baker_bake_cake_async (Baker *self,
* guint radius,
* GAsyncReadyCallback callback,
* gpointer user_data)
* {
* GSimpleAsyncResult *simple;
* Cake *cake;
*
* if (radius < 3)
* {
* g_simple_async_report_error_in_idle (G_OBJECT (self),
* callback,
* user_data,
* BAKER_ERRORS,
* BAKER_ERROR_TOO_SMALL,
* "%ucm radius cakes are silly",
* radius);
* return;
* }
*
* simple = g_simple_async_result_new (G_OBJECT (self),
* callback,
* user_data,
* baker_bake_cake_async);
* cake = _baker_get_cached_cake (self, radius);
*
* if (cake != NULL)
* {
* g_simple_async_result_set_op_res_gpointer (simple,
* g_object_ref (cake),
* g_object_unref);
* g_simple_async_result_complete_in_idle (simple);
* g_object_unref (simple);
* /&ast; Drop the reference returned by _baker_get_cached_cake(); the
* &ast; GSimpleAsyncResult has taken its own reference.
* &ast;/
* g_object_unref (cake);
* return;
* }
*
* _baker_prepare_cake (self, radius, baked_cb, user_data);
* }
*
* Cake *
* baker_bake_cake_finish (Baker *self,
* GAsyncResult *result,
* GError **error)
* {
* GSimpleAsyncResult *simple;
* Cake *cake;
*
* g_return_val_if_fail (g_simple_async_result_is_valid (result,
* G_OBJECT (self),
* baker_bake_cake_async),
* NULL);
*
* simple = (GSimpleAsyncResult *) result;
*
* if (g_simple_async_result_propagate_error (simple, error))
* return NULL;
*
* cake = CAKE (g_simple_async_result_get_op_res_gpointer (simple));
* return g_object_ref (cake);
* }
* ]|
*/
static void g_simple_async_result_async_result_iface_init (GAsyncResultIface *iface);
......
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