public TurtlesimPublish(string topic, IMessageDispatcher messageDispatcher)
{
InitializeComponent();
Loaded += TurtlesimPublish_Loaded;
Closing += TurtlesimPublish_Closing;
_publisher = new Publisher <Twist>(topic, messageDispatcher, new RosMessageTypeAttributeHelper());
_viewModel = new TurtlesimPublishViewModel(topic, MIN_STEP, MAX_STEP);
}
public static void WaitForAnySubscriber(this IRosPublisher publisher, CancellationToken token = default)
{
if (publisher == null)
{
throw new ArgumentNullException(nameof(publisher));
}
Task.Run(() => publisher.WaitForAnySubscriberAsync(token), token).WaitAndRethrow();
}
public static void WaitForAnySubscriber(this IRosPublisher publisher, int timeoutInMs)
{
using CancellationTokenSource tokenSource = new(timeoutInMs);
try
{
publisher.WaitForAnySubscriber(tokenSource.Token);
}
catch (OperationCanceledException)
{
throw new TimeoutException("Wait for subscriber timed out");
}
}
public static async Task WaitForAnySubscriberAsync(this IRosPublisher publisher,
CancellationToken token = default)
{
if (publisher == null)
{
throw new ArgumentNullException(nameof(publisher));
}
if (publisher.NumSubscribers != 0)
{
return;
}
using var linkedSource = CancellationTokenSource.CreateLinkedTokenSource(token, publisher.CancellationToken);
while (publisher.NumSubscribers == 0)
{
await Task.Delay(200, linkedSource.Token);
}
}
private async void TurtlesimPublish_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
await _publisher.UnadvertiseAsync();
_publisher = null;
}
