/// <summary>
/// This method is used to post calls to the parent engine by the Localnode class
/// </summary>
internal void PostMessageToParent(LocalCallDescriptor callDescriptor, bool waitForCompletion)
{
nodeCommandQueue.Enqueue(callDescriptor);
try
{
if (waitForCompletion)
{
// We should not be on the running on the callback writer thread
ErrorUtilities.VerifyThrow(Thread.CurrentThread != writerThread, "Should never call this function from the writer thread");
// We need to block until the event we posted has been processed, but if the writer thread
// exit due to an error the shared memory is no longer valid so there is no way to send the message
while (!writerThreadHasExited && nodeCommandQueue.Count > 0)
{
nodeCommandQueue.QueueEmptyEvent.WaitOne(1000, false);
// Check if the communication threads are supposed to exit
if (exitCommunicationThreads.WaitOne(0, false))
{
break;
}
}
}
}
catch (Exception e)
{
// Clear the current queue since something in the queue has caused a problem
nodeCommandQueue.Clear();
// Try to send the exception back to the parent
localNode.ReportNonFatalCommunicationError(e);
}
}
/// <summary>
/// Given a non-void call descriptor, calls it and retrieves the return value.
/// </summary>
/// <param name="callDescriptor"></param>
/// <returns></returns>
private object GetReplyForCallDescriptor(LocalCallDescriptor callDescriptor)
{
// ReplyFromParentArrived is a TLS field, so initialize it if it's empty
if (replyFromParentArrived == null)
{
replyFromParentArrived = new ManualResetEvent(false);
}
replyFromParentArrived.Reset();
int requestingCallNumber = callDescriptor.CallNumber;
ReplyData replyData = new ReplyData();
replyData.waitEvent = replyFromParentArrived;
// Register our wait event for the call id
lock (repliesFromParent)
{
repliesFromParent[requestingCallNumber] = replyData;
}
nodeCommandQueue.Enqueue(callDescriptor);
replyFromParentArrived.WaitOne();
LocalCallDescriptor reply = null;
// Unregister the wait event
lock (repliesFromParent)
{
// Get the reply
reply = replyData.reply;
ErrorUtilities.VerifyThrow(reply != null, "We must have a reply if the wait event was set");
repliesFromParent.Remove(requestingCallNumber);
}
return(reply.GetReplyData());
}