/// <summary>
/// ParallelSelect
/// </summary>
/// <param name="queue"></param>
/// <param name="parallelWorker"></param>
/// <param name="func"></param>
/// <param name="capacity"></param>
/// <typeparam name="T"></typeparam>
/// <typeparam name="U"></typeparam>
/// <returns></returns>
public static IQueueSource <U> ParallelSelect <T, U>(this IQueueSource <T> queue, ParallelWorker parallelWorker, Func <T, Task <U> > func, int?capacity = null)
{
AsyncQueue <U> outQueue = new AsyncQueue <U>(capacity ?? 2);
IdleDetector idleDetector = new IdleDetector();
Func <Task> workPoster = async delegate {
while (true)
{
Optional <T> item = await queue.Dequeue(CancellationToken.None);
if (!item.HasValue)
{
break;
}
T itemValue = item.Value;
idleDetector.Enter();
Task doingWork = await parallelWorker.StartWorkItem
(
async (int workerId) => {
try {
U item2 = await func(itemValue);
await outQueue.Enqueue(item2, CancellationToken.None);
}
finally {
idleDetector.Leave();
}
},
CancellationToken.None
);
}
await idleDetector.WaitForIdle(CancellationToken.None);
outQueue.WriteEof();
};
Task.Run(workPoster);
return(outQueue);
}
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);
}
