public IAsyncResult BeginAdd(Message msg, ulong id, AsyncCallback cb, object state)
{
try
{
this.rwLock.EnterWriteLock();
this.PurgeExpired();
var cmsg = new CachedMessage(msg.SignalKey, msg.Value, msg.Created, id);
if (this.messageIndex.Count + 1 < CapacityLimit)
{
// add and complete
this.AddToCache(cmsg);
return new CompletedAsyncResult(cb, state);
}
else
{
// move the 'Add' operation to pending until we've got room to
// add the item and complete once the item has been dequeued
// calling Complete on the AR
var addAsyncResult = new AddAsyncResult(cb, state);
this.pendingAdds.EnqueueAndDispatch(cmsg, addAsyncResult.Complete);
return addAsyncResult;
}
}
finally
{
this.rwLock.ExitWriteLock();
}
}
void AddToCache(CachedMessage msg)
{
try
{
this.rwLock.EnterWriteLock();
this.messageIndex.Add(msg.Id, msg);
}
finally
{
this.rwLock.ExitWriteLock();
}
// swap the pending gets queue so that we can drain the old
// one and re-enqueue what we can't service right now
var copiedPendingNotifications = Interlocked.Exchange(ref this.pendingNotifications, new InputQueue<NotificationRegistration>());
for (; ; )
{
NotificationRegistration notificationRegistration;
if (copiedPendingNotifications.Dequeue(TimeSpan.Zero, out notificationRegistration))
{
if (!notificationRegistration.Cancelled)
{
if (notificationRegistration.EventKey.Equals(msg.SignalKey))
{
SimpleIOThreadScheduler.ScheduleCallback(
(pg) => ((NotificationRegistration)pg).Callback(),
(e) => true,
notificationRegistration);
}
else
{
this.pendingNotifications.EnqueueWithoutDispatch(notificationRegistration, null);
}
}
}
else
{
break;
}
}
}