public static Func <Task> ParallelForEach <T>(IQueueSource <T>[] sources, InputPriorities inputPriorities, ParallelWorker parallelWorker, Func <ForEachInfo <T>, Task> processAsync, Func <Task> onCloseAsync, ExceptionCollector ec)
{
Func <Task> t = async delegate()
{
IdleDetector idleDetector = new IdleDetector();
try
{
int sourceCount = sources.Length;
bool[] atEof = new bool[sourceCount];
RoundRobinLoopGenerator loop = new RoundRobinLoopGenerator(sourceCount, inputPriorities);
while (!(atEof.All(e => e)))
{
var ops = Utils.OperationStarters <int, Option <T> >();
loop.ForEach
(
j => { ops = ops.AddIf(!atEof[j], j, Utils.StartableGet <T, Option <T> >(sources[j], a => new Some <T>(a), new None <T>())); }
);
Tuple <int, Option <T> > result = await ops.CompleteAny(ec.CancellationToken);
if (result.Item2.HasValue)
{
int sourceIndex = result.Item1;
T itemValue = result.Item2.Value;
idleDetector.Enter();
await parallelWorker.StartWorkItem
(
async workerId =>
{
try
{
await processAsync(new ForEachInfo <T>(itemValue, sourceIndex, workerId, ec.CancellationToken));
}
catch (Exception exc)
{
ec.Add(exc);
}
finally
{
idleDetector.Leave();
}
},
ec.CancellationToken
);
}
else
{
atEof[result.Item1] = true;
}
}
}
finally
{
if (onCloseAsync != null)
{
try
{
await onCloseAsync();
}
catch (Exception exc)
{
ec.Add(exc);
}
}
}
};
return(t);
}
