LockFreeListWindow Find(LockFreeNode node)
{
if (head == null || node == null)
{
return null;
}
LockFreeNode previous = null;
LockFreeNode current = head;
while (current != null && !current.Equals(node))
{
if (current.GetNext() == null)
{
return null;
}
previous = current;
current = current.GetNext();
}
if(current == null)
{
return null;
}
return new LockFreeListWindow(previous, current);
}
public void Add(LockFreeNode node)
{
if(node == null)
{
return;
}
if(node.IsLogicallyRemoved)
{
node.IsLogicallyRemoved = false;
}
while(true)
{
if(Contains(node))
{
return;
}
node.SetNext(head);
if(Interlocked.CompareExchange(ref head, node, node.GetNext()) != head)
{
return;
}
}
}
public bool Contains(LockFreeNode node)
{
if (node == null)
{
return false;
}
LockFreeListWindow window = Find(node);
if(window == null)
{
return false;
}
if (window.Current.IsLogicallyRemoved)
{
return false;
}
return true;
}
public void Remove(LockFreeNode node)
{
if(node == null)
{
return;
}
while(true)
{
LockFreeListWindow window = Find(node);
if(window == null)
{
return;
}
window.Current.IsLogicallyRemoved = true;
if(window.Previous == null)
{
if(Interlocked.CompareExchange(ref head, window.Current.GetNext(), window.Current) == window.Current)
{
return;
}
}
else
{
if(window.Previous.IsLogicallyRemoved)
{
continue;
}
if (Interlocked.CompareExchange(ref window.Previous.GetRefNext(), window.Current.GetNext(), window.Current) == window.Current)
{
return;
}
}
}
}