private static async Task RunLoopAsync <T>(
EnumeratorInfo <T> enumerator,
T item,
int index,
ConcurrentQueue <Exception> exceptions,
Func <T, int, CancellationToken, Task> func,
CancellationToken cancelToken)
{
do
{
if (exceptions.Count > 0)
{
return;
}
try
{
await func(item, index, cancelToken).ConfigureAwait(false);
}
catch (Exception ex)
{
exceptions.Enqueue(ex);
return;
}
}while (enumerator.TryGetNext(out item, out index));
}
public static async Task WhenAll <T>(
this IEnumerable <T> enumerable,
CancellationToken cancelToken,
Func <T, int, CancellationToken, Task> func,
int?maxParallelization = null)
{
if (enumerable == null)
{
throw new ArgumentNullException(nameof(enumerable));
}
if (func == null)
{
throw new ArgumentNullException(nameof(func));
}
var exceptions = new ConcurrentQueue <Exception>();
var maxCount = maxParallelization ?? Environment.ProcessorCount;
var tasks = new List <Task>(maxCount);
using (var enumerator = new EnumeratorInfo <T>(enumerable))
{
for (var i = 0; i < maxCount; i++)
{
T item;
int index;
if (!enumerator.TryGetNext(out item, out index))
{
break;
}
var task = RunLoopAsync(enumerator, item, index, exceptions, func, cancelToken);
tasks.Add(task);
}
await Task.WhenAll(tasks).ConfigureAwait(false);
}
if (exceptions.Count > 0)
{
throw new AggregateException(exceptions);
}
}
