public void TryDelivery(QueueEntry head)
{
// TODO: check link credit to determine if we can deliver
if (!HasCreditToDeliver())
{
return;
}
lock (syncRoot)
{
var next = head.GetNextValidEntry();
while (next != null)
{
if (next.IsAvailable)
{
// TODO: FILTER out entries we don't care about
if (queue.TryAcquire(next, this))
{
break; // if not acquired, we'll try again with the next one
}
}
// loop until we get an available entry to deliver
// or null
next = next.GetNextValidEntry();
}
if (next == null)
{
return; // nothing to deliver
}
if (next != null)
{
// message acquired and ready to be delivered
OnMessageAquired(next);
}
}
}
public void WriteArchived(ConcurrentQueue queue, QueueEntry entry)
{
buffer.Enqueue(
string.Format("Queue {0} Archived {1} DateTime {2} TTL {3} DeliveryCount {4}", queue.QueueID, entry.SeqNum, entry.EnqueueDateTime, entry.TTL, entry.DeliveryCount));
flushSignal.Set();
}
/// <summary>
/// Wraps up call to Interlocked.CompareExchange to compare & swap a new
/// "next" QueueEntry pointer.
///
/// Returns true if the compare & swap succeeded, false other.
/// </summary>
public bool CompareAndSwapNext(QueueEntry n_next, QueueEntry p_next)
{
return(Interlocked.CompareExchange(ref next, n_next, p_next) == p_next);
}
/// <summary>
/// Compares the sequence number of this QueueEntry to another QueueEntry for ordering purposes.
/// </summary>
public int CompareTo(QueueEntry item)
{
// TODO: sequence number wrapping
return(SeqNum > item.SeqNum ? 1 : SeqNum < item.SeqNum ? -1 : 0);
}
protected abstract void OnMessageAquired(QueueEntry next);
public bool TryAcquire(QueueEntry entry, Consumer consumer)
{
return(entry.TryAcquire(consumer));
}
public void Archive(QueueEntry entry)
{
entry.Archive();
logWriter.WriteArchived(this, entry);
queueList.OnEntryArchived(entry);
}
public void Release(QueueEntry entry, bool incrementDeliveryCount)
{
entry.Release(incrementDeliveryCount);
messageDeliveryPumpSignal.Set(); // new message available, signal to pump to consumers
}