// Transform
public static async Task Transform <TIn, TOut>(
this ChannelReader <TIn> reader,
ChannelWriter <TOut> writer,
Func <TIn, TOut> transformer,
ChannelCompletionMode channelCompletionMode = ChannelCompletionMode.CompleteAndPropagateError,
CancellationToken cancellationToken = default)
{
try {
while (await reader.WaitToReadAsync(cancellationToken).ConfigureAwait(false))
{
if (reader.TryRead(out var item))
{
var newItem = transformer.Invoke(item);
await writer.WriteAsync(newItem, cancellationToken).ConfigureAwait(false);
}
}
if ((channelCompletionMode & ChannelCompletionMode.Complete) != 0)
{
writer.TryComplete();
}
}
catch (OperationCanceledException) {
throw;
}
catch (Exception e) {
if (channelCompletionMode == ChannelCompletionMode.CompleteAndPropagateError)
{
writer.TryComplete(e);
}
else
{
throw;
}
}
}
public static async Task Copy <T>(
this ChannelReader <T> reader,
ChannelWriter <T> writer,
ChannelCompletionMode channelCompletionMode,
CancellationToken cancellationToken = default)
{
try {
while (await reader.WaitToReadAsync(cancellationToken).ConfigureAwait(false))
{
while (reader.TryRead(out var value))
{
await writer.WriteAsync(value, cancellationToken).ConfigureAwait(false);
}
}
if ((channelCompletionMode & ChannelCompletionMode.PropagateCompletion) != 0)
{
writer.TryComplete();
}
}
catch (OperationCanceledException oce) {
if ((channelCompletionMode & ChannelCompletionMode.PropagateCancellation) != 0)
{
writer.TryComplete(oce);
}
throw;
}
catch (Exception e) {
if ((channelCompletionMode & ChannelCompletionMode.PropagateError) != 0)
{
writer.TryComplete(e);
}
throw;
}
}
public static async Task CopyTo <T>(this IAsyncEnumerable <T> source,
ChannelWriter <T> writer,
ChannelCompletionMode channelCompletionMode,
CancellationToken cancellationToken = default)
{
try {
await foreach (var item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
{
await writer.WriteAsync(item, cancellationToken).ConfigureAwait(false);
}
if ((channelCompletionMode & ChannelCompletionMode.Complete) != 0)
{
writer.TryComplete();
}
}
catch (OperationCanceledException) {
throw;
}
catch (Exception e) {
if (channelCompletionMode == ChannelCompletionMode.CompleteAndPropagateError)
{
writer.TryComplete(e);
}
else
{
throw;
}
}
}
public static Task Connect <T1, T2>(
this Channel <T1> channel1, Channel <T2> channel2,
Func <T1, T2> adapter12, Func <T2, T1> adapter21,
ChannelCompletionMode channelCompletionMode,
CancellationToken cancellationToken = default)
=> Task.WhenAll(
Task.Run(() => channel1.Reader.Transform(
channel2, adapter12, channelCompletionMode, cancellationToken), CancellationToken.None),
Task.Run(() => channel2.Reader.Transform(
channel1, adapter21, channelCompletionMode, cancellationToken), CancellationToken.None)
);
public static Task Connect <T>(
this Channel <T> channel1,
Channel <T> channel2,
ChannelCompletionMode channelCompletionMode,
CancellationToken cancellationToken = default)
=> Task.WhenAll(
Task.Run(() => channel1.Reader.Copy(
channel2, channelCompletionMode, cancellationToken), CancellationToken.None),
Task.Run(() => channel2.Reader.Copy(
channel1, channelCompletionMode, cancellationToken), CancellationToken.None)
);
// ConcurrentTransform
public static async Task ConcurrentTransform <TIn, TOut>(
this ChannelReader <TIn> reader,
ChannelWriter <TOut> writer,
Func <TIn, TOut> transformer,
int concurrencyLevel = -1,
ChannelCompletionMode channelCompletionMode = ChannelCompletionMode.CompleteAndPropagateError,
CancellationToken cancellationToken = default)
{
if (concurrencyLevel < 0)
{
concurrencyLevel = HardwareInfo.GetProcessorCountFactor();
}
var semaphore = new SemaphoreSlim(concurrencyLevel, concurrencyLevel);
Exception?error = null;
async Task Worker()
{
try {
for (;;)
{
await semaphore !.WaitAsync(cancellationToken).ConfigureAwait(false);
try {
if (!await reader.WaitToReadAsync(cancellationToken).ConfigureAwait(false))
{
break;
}
if (!reader.TryRead(out var item))
{
continue;
}
var newItem = transformer.Invoke(item);
await writer.WriteAsync(newItem, cancellationToken).ConfigureAwait(false);
}
finally {
semaphore.Release();
}
}
}
catch (OperationCanceledException) {
throw;
}
catch (Exception e) {
if (channelCompletionMode == ChannelCompletionMode.CompleteAndPropagateError)
{
error = e;
}
else
{
throw;
}
}
}
var workers = new Task[concurrencyLevel];
for (var i = 0; i < concurrencyLevel; i++)
{
workers[i] = Task.Run(Worker, cancellationToken);
}
await Task.WhenAll(workers).ConfigureAwait(false);
if ((channelCompletionMode & ChannelCompletionMode.Complete) != 0)
{
writer.TryComplete(error);
}
}
