private CancellationTokenRegistration Register(Action<Object> callback, Object state, bool useSynchronizationContext, bool useExecutionContext)
{
StackCrawlMark stackMark = StackCrawlMark.LookForMyCaller;
if (callback == null)
throw new ArgumentNullException("callback");
if (CanBeCanceled == false)
{
return new CancellationTokenRegistration(); // nothing to do for tokens than can never reach the canceled state. Give them a dummy registration.
}
// Capture sync/execution contexts if required.
// Note: Only capture sync/execution contexts if IsCancellationRequested = false
// as we know that if it is true that the callback will just be called synchronously.
SynchronizationContext capturedSyncContext = null;
ExecutionContext capturedExecutionContext = null;
if (!IsCancellationRequested)
{
if (useSynchronizationContext)
capturedSyncContext = SynchronizationContext.Current;
if (useExecutionContext)
capturedExecutionContext = ExecutionContext.Capture(
ref stackMark, ExecutionContext.CaptureOptions.OptimizeDefaultCase); // ideally we'd also use IgnoreSyncCtx, but that could break compat
}
// Register the callback with the source.
return m_source.InternalRegister(callback, state, capturedSyncContext, capturedExecutionContext);
}
public CancellationTokenRegistration Register(Action <Object> callback, Object state, bool useSynchronizationContext, bool useExecutionContext)
{
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
if (CanBeCanceled == false)
{
return(new CancellationTokenRegistration()); // nothing to do for tokens than can never reach the canceled state. Give them a dummy registration.
}
// Capture sync/execution contexts if required.
// Note: Only capture sync/execution contexts if IsCancellationRequested = false
// as we know that if it is true that the callback will just be called synchronously.
SynchronizationContext capturedSyncContext = null;
ExecutionContext capturedExecutionContext = null;
if (!IsCancellationRequested)
{
if (useSynchronizationContext)
{
capturedSyncContext = SynchronizationContext.Current;
}
if (useExecutionContext)
{
capturedExecutionContext = ExecutionContext.Capture();
}
}
// Register the callback with the source.
return(m_source.InternalRegister(callback, state, capturedSyncContext, capturedExecutionContext));
}
private CancellationTokenRegistration PrivateRegister(Action <Object> callback, Object state)
{
if (callback == null)
{
throw new ArgumentNullException("callback");
}
if (CanBeCanceled == false)
{
return(new CancellationTokenRegistration()); // nothing to do for tokens than can never reach the canceled state. Give them a dummy registration.
}
// Register the callback with the source.
return(m_source.InternalRegister(callback, state, null, null));
}