private Tuple <ITargetBlock <Assembly>, Task <DiscoveredParts> > CreateAssemblyDiscoveryBlockChain(IProgress <DiscoveryProgress> progress, CancellationToken cancellationToken)
{
var progressFilter = new ProgressFilter(progress);
var tuple = this.CreateDiscoveryBlockChain(false, progressFilter, cancellationToken);
var exceptions = new List <PartDiscoveryException>();
var assemblyBlock = new TransformManyBlock <Assembly, Type>(
a =>
{
IReadOnlyCollection <Type> types;
try
{
// Fully realize any enumerable now so that we can catch the exception rather than
// leave it to dataflow to catch it.
types = this.GetTypes(a).ToList();
}
catch (ReflectionTypeLoadException ex)
{
var partDiscoveryException = new PartDiscoveryException(string.Format(CultureInfo.CurrentCulture, Strings.ReflectionTypeLoadExceptionWhileEnumeratingTypes, a.Location), ex)
{
AssemblyPath = a.Location
};
lock (exceptions)
{
exceptions.Add(partDiscoveryException);
}
types = ex.Types.Where(t => t != null).ToList();
}
catch (Exception ex)
{
var partDiscoveryException = new PartDiscoveryException(string.Format(CultureInfo.CurrentCulture, Strings.UnableToEnumerateTypes, a.Location), ex)
{
AssemblyPath = a.Location
};
lock (exceptions)
{
exceptions.Add(partDiscoveryException);
}
return(Enumerable.Empty <Type>());
}
progressFilter.OnDiscoveredMoreTypes(types.Count);
return(types);
},
new ExecutionDataflowBlockOptions
{
MaxDegreeOfParallelism = Debugger.IsAttached ? 1 : Environment.ProcessorCount,
CancellationToken = cancellationToken,
});
assemblyBlock.LinkTo(tuple.Item1, new DataflowLinkOptions {
PropagateCompletion = true
});
var tcs = new TaskCompletionSource <DiscoveredParts>();
Task.Run(async delegate
{
try
{
var parts = await tuple.Item2.ConfigureAwait(false);
tcs.SetResult(parts.Merge(new DiscoveredParts(Enumerable.Empty <ComposablePartDefinition>(), exceptions)));
}
catch (Exception ex)
{
tcs.SetException(ex);
}
});
return(Tuple.Create <ITargetBlock <Assembly>, Task <DiscoveredParts> >(assemblyBlock, tcs.Task));
}