/// <summary>Returns an item, blocking if not ready</summary>
/// <remarks>returns <see cref="Maybe{T}.None()"/> without blocking if the channel is closed</remarks>
public Maybe <T> Recv()
{
Waiter <T> r;
lock (sync) {
if (!items.Empty)
{
var value = items.Dequeue();
Debug.Print("Thread {0}, {1} Recv, removed item from itemq", Thread.CurrentThread.ManagedThreadId, GetType());
MoveSendQToItemQ();
return(Maybe <T> .Some(value));
}
Waiter <T> s = senders.Dequeue();
if (s != null)
{
Debug.Print("Thread {0}, {1} Recv, waking sender", Thread.CurrentThread.ManagedThreadId, GetType());
var mv = s.Value;
s.Wakeup();
return(mv);
}
if (closed)
{
Debug.Print("Thread {0}, {1} Recv, Channel is closed", Thread.CurrentThread.ManagedThreadId, GetType());
return(Maybe <T> .None());
}
r = WaiterPool <T> .Get();
receivers.Enqueue(r);
}
// wait for a sender to signal it has sent
Debug.Print("Thread {0}, {1} Recv, waiting", Thread.CurrentThread.ManagedThreadId, GetType());
r.WaitOne();
Debug.Print("Thread {0}, {1} Recv, woke up", Thread.CurrentThread.ManagedThreadId, GetType());
var v = r.Value;
WaiterPool <T> .Put(r);
return(v);
}
/// <summary>Send a value, adds it to the item queue or blocks until the queue is no longer full</summary>
public void Send(T v)
{
Waiter <T> s;
lock (sync) {
if (closed)
{
throw new ClosedChannelException("You cannot send on a closed Channel");
}
if (items.Empty)
{
Waiter <T> wr = receivers.Dequeue();
if (wr != null)
{
wr.Value = Maybe <T> .Some(v);
Debug.Print("Thread {0}, {1} Send({2}), SetItem succeeded", Thread.CurrentThread.ManagedThreadId, GetType(), wr.Value);
wr.Wakeup();
return;
}
}
if (!items.Full)
{
Debug.Print("Thread {0}, {1} Send({2}), spare capacity, adding to itemq", Thread.CurrentThread.ManagedThreadId, GetType(), v);
items.Enqueue(v);
return;
}
// at capacity, queue our waiter until some capacity is freed up by a recv
s = WaiterPool <T> .Get(v);
senders.Enqueue(s);
}
// wait for the receiver to wake us up
Debug.Print("Thread {0}, {1} Send({2}), waiting ", Thread.CurrentThread.ManagedThreadId, GetType(), v);
s.WaitOne();
Debug.Print("Thread {0}, {1} Send({2}), woke up after waiting ", Thread.CurrentThread.ManagedThreadId, GetType(), v);
WaiterPool <T> .Put(s);
}
void IChannel.ReleaseWaiter(IWaiter h)
{
WaiterPool <T> .Put((Waiter <T>) h);
}
/// <summary>Gets a waiter for use in RecvSelect</summary>
IWaiter IChannel.GetWaiter()
{
return(WaiterPool <T> .Get());
}