/// <summary>
/// Will at least try to process all queued system messages: in case of
/// failure simply drop and go on to the next, because there is nothing to
/// restart here (failure is in <see cref="ActorCell"/> somewhere …). In case the mailbox
/// becomes closed (because of processing a <see cref="Terminate"/> message), dump all
/// already dequeued message to deadLetters.
/// </summary>
private void ProcessAllSystemMessages()
{
Exception interruption = null;
var messageList = SystemDrain(SystemMessageList.LNil);
while (messageList.NonEmpty && !IsClosed())
{
var msg = messageList.Head;
messageList = messageList.Tail;
msg.Unlink();
DebugPrint("{0} processing system message {1} with {2}", Actor.Self, msg, string.Join(",", Actor.GetChildren()));
// we know here that SystemInvoke ensures that only "fatal" exceptions get rethrown
#if UNSAFE_THREADING
try
{
Actor.SystemInvoke(msg);
}
catch (ThreadInterruptedException ex)
// thrown only if thread is explicitly interrupted, which should never happen
{
interruption = ex;
}
catch (ThreadAbortException ex) // can be thrown if dispatchers shutdown / application terminates / etc
{
interruption = ex;
}
#else
Actor.SystemInvoke(msg);
#endif
// don't ever execute normal message when system message present!
if (messageList.IsEmpty && !IsClosed())
{
messageList = SystemDrain(SystemMessageList.LNil);
}
}
/*
* if we closed the mailbox, we must dump the remaining system messages
* to deadLetters (this is essential for DeathWatch)
*/
var dlm = Actor.Dispatcher.Mailboxes.DeadLetterMailbox;
while (messageList.NonEmpty)
{
var msg = messageList.Head;
messageList = messageList.Tail;
msg.Unlink();
try
{
dlm.SystemEnqueue(Actor.Self, msg);
}
#if UNSAFE_THREADING
catch (ThreadInterruptedException ex)
// thrown only if thread is explicitly interrupted, which should never happen
{
interruption = ex;
}
catch (ThreadAbortException ex) // can be thrown if dispatchers shutdown / application terminates / etc
{
interruption = ex;
}
#endif
catch (Exception ex)
{
Actor.System.EventStream.Publish(new Error(ex, GetType().FullName, GetType(), $"error while enqueuing {msg} to deadletters: {ex.Message}"));
}
}
// if we got an interruption while handling system messages, rethrow it
if (interruption != null)
{
// no need to clear interrupted flag in CLR, unlike JVM
throw interruption;
}
}