// auxiliary method: grant access to the first waiting writer
private void GrantAccessToAWaitingWriter()
{
if (writeReqQueue.Count > 0)
{
LinkedListNode <bool> reqNode = writeReqQueue.First;
reqNode.Value = true; // set request.done to true
state = -1; // exclusive lock was taken
writeReqQueue.RemoveFirst();
MonitorEx.Pulse(monitor, reqNode); // notify the waiting writer
}
}
// send a message to the queue
public void Send(T sentMsg)
{
lock (monitor) {
UpdateStateOnSend(sentMsg);
if (reqQueue.Count > 0)
{
Request request = reqQueue.First.Value;
reqQueue.RemovestFirst();
request.receivedMsg = ReceiveSideEffect();
request.done = true;
// notify waiting thread on its private condition variable
MonitorEx.Pulse(monitor, request);
}
}
}
// perform the possible pending acquires
private void PerformPossibleAcquires()
{
while (reqQueue.Count > 0)
{
Request request = reqQueue.First.Value;
if (!CanAcquire(request.acquires))
{
break;
}
// remove request from queue and satisfy it
reqQueue.RemoveFirst();
AcquireSideEffect(request.acquires);
request.done = true;
MonitorEx.Pulse(monitor, request); // *specific thread notification*
}
}
// send a message to the queue (optimized)
public void SendOptimized(T sentMsg)
{
lock (monitor) {
if (reqQueue.Count > 0)
{
// deliver the message directly to a blocked thread
Request request = reqQueue.First.Value;
reqQueue.Remove(request);
request.receivedMsg = sentMsg;
request.done = true;
// notify waiting thread on its private conditions variable
MonitorEx.Pulse(monitor, request);
}
else
{
// no receiving thread, so the message is left in the respective queue
UpdateStateDueToSend(sentMsg);
}
}
}