Struct gio::AsyncInitable

#[repr(transparent)]
pub struct AsyncInitable { /* private fields */ }

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 AsyncInitableExt::init_async() under the cover, calling back with None and a set GError on failure.

A typical implementation might look something like this:

⚠️ 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;
}

Implements

AsyncInitableExt

Implementations

impl AsyncInitable

pub fn new_async<O: Sized + IsClass + IsA<Object> + IsA<AsyncInitable>, P: IsA<Cancellable>, Q: FnOnce(Result<O, Error>) + 'static>( properties: &[(&str, &dyn ToValue)], io_priority: Priority, cancellable: Option<&P>, callback: Q )

Helper function for constructing AsyncInitable object. This is similar to glib::Object::new() but also initializes the object asynchronously.

When the initialization is finished, callback will be called. You can then call g_async_initable_new_finish() to get the new object and check for any errors.

object_type

a GType supporting AsyncInitable.

io_priority

the [I/O priority][io-priority] of the operation

cancellable

optional Cancellable object, None to ignore.

callback

a GAsyncReadyCallback to call when the initialization is finished

first_property_name

the name of the first property, or None if no properties

pub fn new_future<O: Sized + IsClass + IsA<Object> + IsA<AsyncInitable>>( properties: &[(&str, &dyn ToValue)], io_priority: Priority ) -> Pin<Box_<dyn Future<Output = Result<O, Error>> + 'static>>

pub fn with_type<P: IsA<Cancellable>, Q: FnOnce(Result<Object, Error>) + 'static>( type_: Type, properties: &[(&str, &dyn ToValue)], io_priority: Priority, cancellable: Option<&P>, callback: Q )

pub fn with_type_future( type_: Type, properties: &[(&str, &dyn ToValue)], io_priority: Priority ) -> Pin<Box_<dyn Future<Output = Result<Object, Error>> + 'static>>

impl AsyncInitable

pub const NONE: Option<&'static AsyncInitable> = None

Trait Implementations

impl Clone for AsyncInitable

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AsyncInitable

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for AsyncInitable

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for AsyncInitable

fn hash<H>(&self, state: &mut H)where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for AsyncInitable

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl<OT: ObjectType> PartialEq<OT> for AsyncInitable

fn eq(&self, other: &OT) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for AsyncInitable

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for AsyncInitable

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for AsyncInitable

impl IsA<AsyncInitable> for DBusConnection

impl IsA<AsyncInitable> for DBusProxy