/// <summary>
/// Reads from any of the specified channels
/// </summary>
/// <param name="callback">The method to call when the read completes, or null.</param>
/// <param name="requests">The list of requests</param>
/// <param name="timeout">The maximum time to wait for a value to read.</param>
/// <param name="priority">The priority used to select a channel, if multiple channels have a value that can be read.</param>
/// <param name="cancelToken">The cancellation token</param>
/// <typeparam name="T">The channel data type.</typeparam>
private static Task <MultisetRequest <T> > ReadOrWriteAnyAsync <T>(Action <object> callback, IEnumerable <MultisetRequest <T> > requests, TimeSpan timeout, MultiChannelPriority priority, CancellationToken cancelToken = default(CancellationToken))
{
// This method could also use the untyped version,
// but using the type version is faster as there are no reflection
// or boxing/typecasting required
var tcs = new TaskCompletionSource <MultisetRequest <T> >();
// We only accept the first offer
var offer = new SingleOffer <MultisetRequest <T> >(tcs, timeout == Timeout.Infinite ? Timeout.InfiniteDateTime : DateTime.Now + timeout, cancelToken);
offer.SetCommitCallback(callback);
switch (priority)
{
case MultiChannelPriority.Fair:
throw new InvalidOperationException(string.Format("Construct a {0} or {1} object to use fair multichannel operations", typeof(MultiChannelSetRead <>).Name, typeof(MultiChannelSetWrite <>).Name));
case MultiChannelPriority.Random:
requests = Shuffle(requests);
break;
default:
// Use the order the input has
break;
}
// Keep a map of awaitable items
// and register the intent to read from a channel in order
var tasks = new Dictionary <Task, MultisetRequest <T> >();
foreach (var c in requests)
{
// Timeout is handled by offer instance
if (c.IsRead)
{
tasks[c.ReadChannel.ReadAsync(offer)] = c;
}
else
{
tasks[c.WriteChannel.WriteAsync(c.Value, offer)] = c;
}
// Fast exit to avoid littering the channels if we are done
if (offer.IsTaken)
{
break;
}
}
offer.ProbePhaseComplete();
if (tasks.Count == 0)
{
tcs.TrySetException(new InvalidOperationException("List of channels was empty"));
return(tcs.Task);
}
tasks.Keys.WhenAnyNonCancelled().ContinueWith(item => Task.Run(() =>
{
if (item.IsCanceled)
{
tcs.TrySetCanceled();
return;
}
else if (item.IsFaulted)
{
tcs.TrySetException(item.Exception);
return;
}
var n = item.Result;
if (offer.AtomicIsFirst())
{
// Figure out which item was found
if (n.IsCanceled)
{
tcs.SetCanceled();
}
else if (n.IsFaulted)
{
// Unwrap aggregate exceptions
if (n.Exception is AggregateException && (n.Exception as AggregateException).Flatten().InnerExceptions.Count == 1)
{
tcs.SetException(n.Exception.InnerException);
}
else
{
tcs.SetException(n.Exception);
}
}
else
{
var orig = tasks[n];
if (orig.IsRead)
{
tcs.SetResult(new MultisetRequest <T>(((Task <T>)n).Result, orig.ReadChannel, null, true));
}
else
{
tcs.SetResult(new MultisetRequest <T>(default(T), null, orig.WriteChannel, false));
}
}
}
}));
return(tcs.Task);
}
/// <summary>
/// Reads or writes any of the specified requests
/// </summary>
/// <param name="callback">The method to call when the read completes, or null.</param>
/// <param name="requests">The list of requests.</param>
/// <param name="timeout">The maximum time to wait for a value to read.</param>
/// <param name="priority">The priority used to select a channel, if multiple channels have a value that can be read.</param>
public static Task <IMultisetRequestUntyped> ReadOrWriteAnyAsync(Action <object> callback, IEnumerable <IMultisetRequestUntyped> requests, TimeSpan timeout, MultiChannelPriority priority)
{
var tcs = new TaskCompletionSource <IMultisetRequestUntyped>();
// We only accept the first offer
var offer = new SingleOffer <IMultisetRequestUntyped>(tcs, timeout == Timeout.Infinite ? Timeout.InfiniteDateTime : DateTime.Now + timeout);
offer.SetCommitCallback(callback);
switch (priority)
{
case MultiChannelPriority.Fair:
throw new Exception(string.Format("Construct a {0} or {1} object to use fair multichannel operations", typeof(MultiChannelSetRead <>).Name, typeof(MultiChannelSetWrite <>).Name));
case MultiChannelPriority.Random:
requests = MultiChannelAccess.Shuffle(requests);
break;
default:
// Use the order the input has
break;
}
// Keep a map of awaitable items
var tasks = new Dictionary <Task, IMultisetRequestUntyped>();
// Then we register the intent to read from a channel in order
foreach (var c in requests)
{
// Timeout is handled by offer instance
if (c.IsRead)
{
tasks[c.Channel.ReadAsync(Timeout.Infinite, offer)] = c;
}
else
{
tasks[c.Channel.WriteAsync(c.Value, Timeout.Infinite, offer)] = c;
}
// Fast exit to avoid littering the channels if we are done
if (offer.IsTaken)
{
break;
}
}
offer.ProbePhaseComplete();
if (tasks.Count == 0)
{
tcs.TrySetException(new InvalidOperationException("List of channels was empty"));
return(tcs.Task);
}
tasks.Keys.WhenAnyNonCancelled().ContinueWith(item => Task.Run(() =>
{
if (item.IsCanceled)
{
tcs.TrySetCanceled();
return;
}
else if (item.IsFaulted)
{
tcs.TrySetException(item.Exception);
return;
}
if (offer.AtomicIsFirst())
{
var n = item.Result;
// Figure out which item was found
if (n.IsCanceled)
{
tcs.SetCanceled();
}
else if (n.IsFaulted)
{
// Unwrap aggregate exceptions
if (n.Exception is AggregateException && (n.Exception as AggregateException).Flatten().InnerExceptions.Count == 1)
{
tcs.SetException(n.Exception.InnerException);
}
else
{
tcs.SetException(n.Exception);
}
}
else
{
var orig = tasks[n];
if (orig.IsRead)
{
orig.Value = ((Task <object>)n).Result;
tcs.SetResult(orig);
}
else
{
orig.Value = null;
tcs.SetResult(orig);
}
}
}
}));
return(tcs.Task);
}