module Gio::AsyncInitable

Overview

GAsyncInitable is an interface for asynchronously initializable objects.

This is the asynchronous version of 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 Gio::AsyncInitable#new_async directly, or indirectly via a foo_thing_new_async() wrapper. This will call 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:

WARNING ⚠️ The following code is in c ⚠️

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;
}

Direct including types

• Gio::DBusConnection
• Gio::DBusObjectManagerClient
• Gio::DBusProxy

Defined in:

lib/gi-crystal/src/auto/gio-2.0/async_initable.cr

Constructors

• .cast(obj : GObject::Object) : self

  Cast a GObject::Object to self, throws a TypeCastError if the cast can't be made.

Class Method Summary

• .cast?(obj : GObject::Object) : self | Nil
• .g_type : UInt64
• .newv_async(object_type : UInt64, n_parameters : UInt32, parameters : GObject::Parameter, io_priority : Int32, cancellable : Gio::Cancellable | Nil, &callback : Gio::AsyncReadyCallback) : Nil

  DEPRECATED

Instance Method Summary

• #init_async(io_priority : Int32, cancellable : Gio::Cancellable | Nil, &callback : Gio::AsyncReadyCallback) : Nil
• #init_finish(res : Gio::AsyncResult) : Bool
• #new_finish(res : Gio::AsyncResult) : GObject::Object
• #to_unsafe

Constructor Detail

Class Method Detail

Instance Method Detail