public override void Take()
{
if (PreCheck())
{
return;
}
WaitNode w = new WaitNode();
w.DoWait(this);
}
internal WaitNode GetSignallee()
{
lock (this)
{
WaitNode w = Queue.Extract();
if (w == null)
{
++Permits; // if none, inc permits for new arrivals
}
return(w);
}
}
public override void Insert(WaitNode node)
{
if (tail_ == null)
{
head_ = tail_ = node;
}
else
{
tail_.Next = node;
tail_ = node;
}
}
public override bool Take(TimeSpan timeout)
{
if (PreCheck())
{
return(true);
}
if (timeout.TotalMilliseconds <= 0)
{
return(false);
}
WaitNode w = new WaitNode();
return(w.DoTimedWait(this, timeout));
}
public override void Release()
{
while (true)
{
WaitNode w = GetSignallee();
if (w == null)
{
return; // no one to signal
}
if (w.Signal())
{
return; // notify if still waiting, else skip
}
}
}
internal bool ReCheck(WaitNode w)
{
lock (this)
{
bool pass = (Permits > 0);
if (pass)
{
--Permits;
}
else
{
Queue.Insert(w);
}
return(pass);
}
}
public override WaitNode Extract()
{
if (head_ == null)
{
return(null);
}
else
{
WaitNode w = head_;
head_ = w.Next;
if (head_ == null)
{
tail_ = null;
}
w.Next = null;
return(w);
}
}
public abstract void Insert(WaitNode node);
