RunAsync< TResult >()

static Task< TResult > System.Net.Dns.RunAsync< TResult > ( Func< object, ValueStopwatch, TResult > func, object key, CancellationToken cancellationToken )

inlinestaticprivate

Definition at line 605 of file Dns.cs.

    {
        ValueStopwatch stopwatch = NameResolutionTelemetry.Log.BeforeResolution(key);
        Task<TResult> task2 = null;
        lock (s_tasks)
        {
            s_tasks.TryGetValue(key, out var value);
            if (value == null)
            {
                value = Task.CompletedTask;
            }
            task2 = value.ContinueWith(delegate
            {
                try
                {
                    return func(key, stopwatch);
                }
                finally
                {
                    lock (s_tasks)
                    {
                        ((ICollection<KeyValuePair<object, Task>>)s_tasks).Remove(new KeyValuePair<object, Task>(key, task2));
                    }
                }
            }, key, cancellationToken, TaskContinuationOptions.DenyChildAttach, TaskScheduler.Default);
            if (cancellationToken.CanBeCanceled)
            {
                task2.ContinueWith(delegate(Task<TResult> task, object key)
                {
                    lock (s_tasks)
                    {
                        ((ICollection<KeyValuePair<object, Task>>)s_tasks).Remove(new KeyValuePair<object, Task>(key, task));
                    }
                }, key, CancellationToken.None, TaskContinuationOptions.OnlyOnCanceled | TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
            }
            s_tasks[key] = task2;
        }
        return task2;
    }

References System.cancellationToken, System.Threading.Tasks.Task< TResult >.CompletedTask, System.Threading.Tasks.TaskScheduler.Default, System.key, System.Net.NameResolutionTelemetry.Log, System.Threading.CancellationToken.None, System.Collections.Generic.Dictionary< TKey, TValue >.Remove(), System.Net.Dns.s_tasks, System.task, and System.value.