//Listing 12.9 Producer/consumer using TPL Dataflow
public static async Task CompressAndEncrypt(
Stream streamSource, Stream streamDestination,
int maxDegreeOfParallelism = 4,
long chunkSize = 1048576, CancellationTokenSource cts = null)
{
cts = cts ?? new CancellationTokenSource(); //#A
var compressorOptions = new ExecutionDataflowBlockOptions
{
MaxDegreeOfParallelism = maxDegreeOfParallelism,
BoundedCapacity = 20,
CancellationToken = cts.Token
}; //#B
var inputBuffer = new BufferBlock <CompressingDetails>(
new DataflowBlockOptions
{
CancellationToken = cts.Token,
BoundedCapacity = 20
}); //#B
var compressor = new TransformBlock <CompressingDetails, CompressedDetails>(
async details =>
{
var compressedData = await IOUtils.Compress(details.Bytes); //#C
return(details.ToCompressedDetails(compressedData)); //#D
}, compressorOptions);
var encryptor = new TransformBlock <CompressedDetails, EncryptDetails>(
async details =>
{
byte[] data = IOUtils.CombineByteArrays(details.CompressedDataSize, details.ChunkSize, details.Bytes); //#E
var encryptedData = await IOUtils.Encrypt(data); //#F
return(details.ToEncryptDetails(encryptedData)); //#D
}, compressorOptions);
var asOrderedAgent = Agent.Start((new Dictionary <int, EncryptDetails>(), 0),
async((Dictionary <int, EncryptDetails>, int)state, EncryptDetails msg) =>
{ //#G
(Dictionary <int, EncryptDetails> details, int lastIndexProc) = state;
details.Add(msg.Sequence, msg);
while (details.ContainsKey(lastIndexProc + 1))
{
msg = details[lastIndexProc + 1];
await streamDestination.WriteAsync(msg.EncryptedDataSize, 0, msg.EncryptedDataSize.Length);
await streamDestination.WriteAsync(msg.Bytes, 0, msg.Bytes.Length); //#H
lastIndexProc = msg.Sequence;
details.Remove(lastIndexProc); //#I
}
return(details, lastIndexProc);
}, cts);
