pub trait CancellableExtManual: Sealed + IsA<Cancellable> {
// Provided methods
fn connect_cancelled<F: FnOnce(&Self) + Send + 'static>(
&self,
callback: F,
) -> Option<CancelledHandlerId> { ... }
fn connect_cancelled_local<F: FnOnce(&Self) + 'static>(
&self,
callback: F,
) -> Option<CancelledHandlerId> { ... }
fn disconnect_cancelled(&self, id: CancelledHandlerId) { ... }
fn future(
&self,
) -> Pin<Box<dyn Future<Output = ()> + Send + Sync + 'static>> { ... }
fn set_error_if_cancelled(&self) -> Result<(), Error> { ... }
}
Provided Methods§
Sourcefn connect_cancelled<F: FnOnce(&Self) + Send + 'static>(
&self,
callback: F,
) -> Option<CancelledHandlerId>
fn connect_cancelled<F: FnOnce(&Self) + Send + 'static>( &self, callback: F, ) -> Option<CancelledHandlerId>
Convenience function to connect to the signal::Cancellable::cancelled
signal. Also
handles the race condition that may happen if the cancellable is cancelled right before
connecting. If the operation is cancelled from another thread, callback
will be called
in the thread that cancelled the operation, not the thread that is running the operation.
This may be the main thread, so the callback should not do something that can block.
callback
is called at most once, either directly at the time of the connect if self
is
already cancelled, or when self
is cancelled in some thread.
Since GLib 2.40, the lock protecting self
is not held when callback
is invoked. This
lifts a restriction in place for earlier GLib versions which now makes it easier to write
cleanup code that unconditionally invokes e.g.
CancellableExt::cancel()
.
§Returns
The id of the signal handler or None
if self
has already been cancelled.
Sourcefn connect_cancelled_local<F: FnOnce(&Self) + 'static>(
&self,
callback: F,
) -> Option<CancelledHandlerId>
fn connect_cancelled_local<F: FnOnce(&Self) + 'static>( &self, callback: F, ) -> Option<CancelledHandlerId>
Local variant of Self::connect_cancelled
.
Sourcefn disconnect_cancelled(&self, id: CancelledHandlerId)
fn disconnect_cancelled(&self, id: CancelledHandlerId)
Disconnects a handler from a cancellable instance. Additionally, in the event that a signal
handler is currently running, this call will block until the handler has finished. Calling
this function from a callback registered with Self::connect_cancelled
will therefore
result in a deadlock.
This avoids a race condition where a thread cancels at the same time as the cancellable operation is finished and the signal handler is removed.
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.