private async Task CopyToAsyncCore(Stream destination, byte[] buffer, CancellationToken cancellationToken)
{
_state.PinReceiveBuffer(buffer);
CancellationTokenRegistration ctr = cancellationToken.Register(s => ((WinHttpResponseStream)s !).CancelPendingResponseStreamReadOperation(), this);
_state.AsyncReadInProgress = true;
try
{
// Loop until there's no more data to be read
while (true)
{
// Query for data available
lock (_state.Lock)
{
if (!Interop.WinHttp.WinHttpQueryDataAvailable(_requestHandle, IntPtr.Zero))
{
throw new IOException(SR.net_http_io_read, WinHttpException.CreateExceptionUsingLastError(nameof(Interop.WinHttp.WinHttpQueryDataAvailable)));
}
}
int bytesAvailable = await _state.LifecycleAwaitable;
if (bytesAvailable == 0)
{
ReadResponseTrailers();
break;
}
Debug.Assert(bytesAvailable > 0);
// Read the available data
cancellationToken.ThrowIfCancellationRequested();
lock (_state.Lock)
{
if (!Interop.WinHttp.WinHttpReadData(_requestHandle, Marshal.UnsafeAddrOfPinnedArrayElement(buffer, 0), (uint)Math.Min(bytesAvailable, buffer.Length), IntPtr.Zero))
{
throw new IOException(SR.net_http_io_read, WinHttpException.CreateExceptionUsingLastError(nameof(Interop.WinHttp.WinHttpReadData)));
}
}
int bytesRead = await _state.LifecycleAwaitable;
if (bytesRead == 0)
{
ReadResponseTrailers();
break;
}
Debug.Assert(bytesRead > 0);
// Write that data out to the output stream
#if NETSTANDARD2_1 || NETCOREAPP
await destination.WriteAsync(buffer.AsMemory(0, bytesRead), cancellationToken).ConfigureAwait(false);
#else
await destination.WriteAsync(buffer, 0, bytesRead, cancellationToken).ConfigureAwait(false);
#endif
}
}
finally
{
_state.AsyncReadInProgress = false;
ctr.Dispose();
ArrayPool <byte> .Shared.Return(buffer);
}
// Leaving buffer pinned as it is in ReadAsync. It'll get unpinned when another read
// request is made with a different buffer or when the state is cleared.
}
public override Task <int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken token)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException("offset");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (count > buffer.Length - offset)
{
throw new ArgumentException("buffer");
}
if (token.IsCancellationRequested)
{
return(Task.FromCanceled <int>(token));
}
CheckDisposed();
if (_state.TcsReadFromResponseStream != null && !_state.TcsReadFromResponseStream.Task.IsCompleted)
{
throw new InvalidOperationException(SR.net_http_no_concurrent_io_allowed);
}
// TODO (Issue 2505): replace with PinnableBufferCache.
if (!_cachedReceivePinnedBuffer.IsAllocated || _cachedReceivePinnedBuffer.Target != buffer)
{
if (_cachedReceivePinnedBuffer.IsAllocated)
{
_cachedReceivePinnedBuffer.Free();
}
_cachedReceivePinnedBuffer = GCHandle.Alloc(buffer, GCHandleType.Pinned);
}
_state.TcsReadFromResponseStream =
new TaskCompletionSource <int>(TaskCreationOptions.RunContinuationsAsynchronously);
_state.TcsQueryDataAvailable =
new TaskCompletionSource <int>(TaskCreationOptions.RunContinuationsAsynchronously);
_state.TcsQueryDataAvailable.Task.ContinueWith((previousTask) =>
{
if (previousTask.IsFaulted)
{
_state.TcsReadFromResponseStream.TrySetException(previousTask.Exception.InnerException);
}
else if (previousTask.IsCanceled || token.IsCancellationRequested)
{
_state.TcsReadFromResponseStream.TrySetCanceled(token);
}
else
{
int bytesToRead;
int bytesAvailable = previousTask.Result;
if (bytesAvailable > count)
{
bytesToRead = count;
}
else
{
bytesToRead = bytesAvailable;
}
lock (_state.Lock)
{
if (!Interop.WinHttp.WinHttpReadData(
_state.RequestHandle,
Marshal.UnsafeAddrOfPinnedArrayElement(buffer, offset),
(uint)bytesToRead,
IntPtr.Zero))
{
_state.TcsReadFromResponseStream.TrySetException(
new IOException(SR.net_http_io_read, WinHttpException.CreateExceptionUsingLastError()));
}
}
}
},
CancellationToken.None, TaskContinuationOptions.None, TaskScheduler.Default);
// TODO: Issue #2165. Register callback on cancellation token to cancel WinHTTP operation.
lock (_state.Lock)
{
if (!Interop.WinHttp.WinHttpQueryDataAvailable(_state.RequestHandle, IntPtr.Zero))
{
_state.TcsReadFromResponseStream.TrySetException(
new IOException(SR.net_http_io_read, WinHttpException.CreateExceptionUsingLastError()));
}
}
return(_state.TcsReadFromResponseStream.Task);
}
