internal void BuildNodeList(int level, DispatcherNode[] nodeList, string[] keyParts)
{
// find/create subnode
nodeList[_Level] = this;
DispatcherNode subNode;
_ChildIndexLock.Enter();
try
{
if (!_ChildIndex.TryGetValue(keyParts[_Level], out subNode))
{
subNode = new DispatcherNode(_Dispatcher, _Level + 1, this);
_ChildIndex.Add(keyParts[_Level], subNode);
}
}
finally
{
_ChildIndexLock.Leave();
}
nodeList[_Level + 1] = subNode;
if (level > (_Level + 1))
{
subNode.BuildNodeList(level, nodeList, keyParts);
}
}
// constructors
internal DispatcherNode(Dispatcher Dispatcher, int level, DispatcherNode parent)
{
_Dispatcher = Dispatcher;
if (level < 0)
{
throw new ArgumentException("Invalid", nameof(level));
}
_Level = level;
if ((level == 0) && (parent != null))
{
throw new ArgumentException("Invalid", nameof(parent));
}
if ((level > 0) && (parent == null))
{
throw new ArgumentNullException(nameof(parent));
}
_Parent = parent;
}
private void ProcessNode(DispatcherItem completedItem)
{
long threadsInTree = IncThreadsInTree();
try
{
if (completedItem != null)
{
// completed item cleanup
DecThreadsInTree();
long debugN = Interlocked.Decrement(ref _ThisNodeRunning);
Debug.Assert(debugN == 0);
_Parent?.DecChildrenRunning();
completedItem = null;
}
bool looping = true;
while (looping)
{
looping = false;
// ensure that at least one pass through the dequeuing logic occurs
_Queue.Locked((queue) =>
{
// we have the queue
// we can dispatch the head of the queue if:
// a) the item is for this level, AND this tree is not running;
// or b) the item is for a lower level, AND this node is not running.
if (queue.Count > 0)
{
DispatcherItem workItem = queue.Peek();
Debug.Assert(workItem.Level >= _Level);
if ((workItem.Level == _Level) &&
(Interlocked.Add(ref _ThisNodeRunning, 0) == 0) &&
(Interlocked.Add(ref _ChildrenRunning, 0) == 0))
{
// item is for this level
// dispatch it to the threadpool
queue.Dequeue();
long debugN = Interlocked.Increment(ref _ThisNodeRunning);
Debug.Assert(debugN == 1);
IncThreadsInTree();
ThreadPool.QueueUserWorkItem(CallbackWrapper, workItem);
}
if ((workItem.Level > _Level) &&
(Interlocked.Add(ref _ThisNodeRunning, 0) == 0))
{
// item is for lower level
// enqueue it to the child
queue.Dequeue();
Interlocked.Increment(ref _ChildrenRunning);
DispatcherNode childNode = workItem.NodeList[_Level + 1];
childNode.Enqueue(workItem);
// dequeue next
looping = true;
}
}
});
} // while looping
}
finally
{
threadsInTree = DecThreadsInTree();
}
if ((threadsInTree == 0) && (_Parent != null))
{
// we are the last thread in this tree - handoff to parent
ThreadPool.QueueUserWorkItem(_Parent.AsyncProcessNode, null);
}
}
