async Task <INode <TState, TCost> > GetNodeAsync()
{
//System.Console.WriteLine($"{Thread.CurrentThread.ManagedThreadId}: GetNodeAsync: 1.");
await ConsumerLock.WaitAsync();
bool hasconsumerlock = true;
try
{
Monitor.Enter(ProducerLock);
while (Nodes.Count <= 0)
{
Monitor.Exit(ProducerLock);
List <Task> MonitoredTasks = new List <Task>(WorkerTasks);
if (MonitoredTasks.Count == 0)
{
throw new QueueExhaustedException();
}
ConsumerLock.Release();
hasconsumerlock = false;
await Task.WhenAny(MonitoredTasks);
await ConsumerLock.WaitAsync();
hasconsumerlock = true;
Monitor.Enter(ProducerLock);
}
var myitem = Nodes[0];
Nodes.RemoveAt(0);
VisitedStates.Add(myitem.State, myitem.AccumulatedCost);
Monitor.Exit(ProducerLock);
return(myitem);
}
finally
{
if (hasconsumerlock)
{
ConsumerLock.Release();
}
}
}
public bool Add(INode <TState, TCost> node)
{
lock (ProducerLock)
{
if (VisitedStates.TryGetValue(node.State, out var oldcost))
{
if (Comparer.Compare(node.AccumulatedCost, oldcost) < 0)
{
VisitedStates.Remove(node.State); //re-open, found better path.
}
else
{
return(false);
}
}
for (var i = 0; i < Nodes.Count; i++)
{
if (Comparer.Compare(node.TotalCost, Nodes[i].TotalCost) < 0)
{
Nodes.Insert(i++, node);
for (; i < Nodes.Count; i++)
{
if (Nodes[i].Equals(node))
{
Nodes.RemoveAt(i--);
}
}
return(true);
}
if (Nodes[i].Equals(node))
{
return(false); //Already present with better priority
}
}
Nodes.Add(node);
return(true);
}
}
public async Task <TRet> PerformWorkerOperationAsync <TRet>(Func <INode <TState, TCost>, Task <TRet> > acquiredoperations)
{
//System.Console.WriteLine($"{Thread.CurrentThread.ManagedThreadId}: Getting node.");
INode <TState, TCost> myitem;
await ConsumerLock.WaitAsync();
bool hasconsumerlock = true;
try
{
Monitor.Enter(ProducerLock);
while (Nodes.Count <= 0)
{
Monitor.Exit(ProducerLock);
List <Task> MonitoredTasks = new List <Task>(WorkerTasks);
if (MonitoredTasks.Count == 0)
{
throw new QueueExhaustedException();
}
ConsumerLock.Release();
hasconsumerlock = false;
await Task.WhenAny(MonitoredTasks);
await ConsumerLock.WaitAsync();
hasconsumerlock = true;
Monitor.Enter(ProducerLock);
}
myitem = Nodes[0];
Nodes.RemoveAt(0);
VisitedStates.Add(myitem.State, myitem.AccumulatedCost);
Monitor.Exit(ProducerLock);
}
catch (Exception)
{
if (hasconsumerlock)
{
ConsumerLock.Release();
}
throw;
}
//Still has consumerlock
TaskCompletionSource <int> holder = new TaskCompletionSource <int>();
async Task <TRet> Worker(INode <TState, TCost> n)
{
await holder.Task;
return(await acquiredoperations(n));
}
var t = Worker(myitem);
var cleanuptask = t.ContinueWith(async x =>
{
await ConsumerLock.WaitAsync();
WorkerTasks.Remove(x);
ConsumerLock.Release();
});
WorkerTasks.Add(t);
ConsumerLock.Release();
holder.SetResult(0); //release hold
await cleanuptask;
return(await t);
}
