private static Task <TResult> WhenAllCore <TResult>(IEnumerable <Task> tasks, Action <Task[], TaskCompletionSource <TResult> > setResultAction)
{
if (tasks == null)
{
throw new ArgumentNullException("tasks");
}
TaskCompletionSource <TResult> tcs = new TaskCompletionSource <TResult>();
Task[] tasks1 = tasks as Task[] ?? tasks.ToArray <Task>();
if (tasks1.Length == 0)
{
setResultAction(tasks1, tcs);
}
else
{
Task.Factory.ContinueWhenAll(tasks1, (Action <Task[]>)(completedTasks =>
{
List <Exception> targetList = (List <Exception>)null;
bool flag = false;
foreach (Task completedTask in completedTasks)
{
if (completedTask.IsFaulted)
{
TaskEx.AddPotentiallyUnwrappedExceptions(ref targetList, (Exception)completedTask.Exception);
}
else if (completedTask.IsCanceled)
{
flag = true;
}
}
if (targetList != null && targetList.Count > 0)
{
tcs.TrySetException((IEnumerable <Exception>)targetList);
}
else if (flag)
{
tcs.TrySetCanceled();
}
else
{
setResultAction(completedTasks, tcs);
}
}), CancellationToken.None, TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
}
return(tcs.Task);
}