/// <summary>
/// Create a message fiber instance
/// </summary>
public MessageFiberBase()
{
RunInternalWaitCallback = RunInternal;
m_SyncContext = new FiberSyncContext(this);
tail = lastTale = new MessageNodeBase()
{
Next = Blocked
};
}
internal void EnqueueInternal(MessageNodeBase newTail)
{
var oldTail = Atomic.Swap(ref tail, newTail);
//if oldtail is null or tailing is failed
if (!TryTail(oldTail, newTail))
{
//statis is a single object in heap, no further allocation with object[]
ThreadPool.QueueUserWorkItem(RunInternalWaitCallback, newTail);
}
}
void RunInternal(object obj)
{
var messageNode = (MessageNodeBase)obj;
//because it's thread specific value, we dont need to set
//null everytime.
CurrentIFiber = this;
var cachedContext = SynchronizationContext.Current;
SynchronizationContext.SetSynchronizationContext(m_SyncContext);
do
{
//restore blocked, let it can be recycle
lastTale.PushToPool();
//remember last tale to be continued
lastTale = messageNode;
try
{
InvokeMessage(messageNode);
}
catch (Exception e)
{
HandleException(e);
}
//if next is null, then it successfully replace it's Next to Blocked
//otherwise messagenode is what recently trytail'ed
messageNode = GetNext(messageNode);
}while (messageNode != null);
SynchronizationContext.SetSynchronizationContext(cachedContext);
//now we're done is this thread pool thread,
CurrentIFiber = null;
}
internal override void InvokeMessage(MessageNodeBase message)
{
message.Invoke();
}
internal abstract void InvokeMessage(MessageNodeBase message);
//get next node and mark it as blocked
//if it's not null, we dont need to execute exchange function
static MessageNodeBase GetNext(MessageNodeBase prev)
{
return(Atomic.Swap(ref prev.Next, Blocked));
}
//if next is already blocked, then previous actions are already executed.
static bool TryTail(MessageNodeBase prev, MessageNodeBase next)
{
return(Atomic.SwapIfSame(ref prev.Next, next, null));
}