Imported Upstream version 5.16.0.100

Former-commit-id: 38faa55fb9669e35e7d8448b15c25dc447f25767

mcs/class/System/System.Net/ContentDecodeStream.cs

@@ -0,0 +1,92 @@
+//
+// ContentDecodeStream.cs
+//
+// Author:
+//       Martin Baulig <mabaul@microsoft.com>
+//
+// Copyright (c) 2018 Xamarin Inc. (http://www.xamarin.com)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+using System;
+using System.IO;
+using System.IO.Compression;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace System.Net
+{
+	class ContentDecodeStream : WebReadStream
+	{
+		internal enum Mode
+		{
+			GZip,
+			Deflate
+		}
+
+		public static ContentDecodeStream Create (
+			WebOperation operation, Stream innerStream, Mode mode)
+		{
+			Stream decodeStream;
+			if (mode == Mode.GZip)
+				decodeStream = new GZipStream (innerStream, CompressionMode.Decompress);
+			else
+				decodeStream = new DeflateStream (innerStream, CompressionMode.Decompress);
+			return new ContentDecodeStream (operation, decodeStream, innerStream);
+		}
+
+		Stream OriginalInnerStream {
+			get;
+		}
+
+		ContentDecodeStream (WebOperation operation, Stream decodeStream,
+		                     Stream originalInnerStream)
+			: base (operation, decodeStream)
+		{
+			/*
+			 * We pass the GZipStream/DeflateStream to the base .ctor,
+			 * so it can Dispose() it when we're done.
+			 * 
+			 * Save the original inner stream here for FinishReading().
+			 */
+			OriginalInnerStream = originalInnerStream;
+		}
+
+		protected override Task<int> ProcessReadAsync (
+			byte[] buffer, int offset, int size,
+			CancellationToken cancellationToken)
+		{
+			return InnerStream.ReadAsync (buffer, offset, size, cancellationToken);
+		}
+
+		internal override Task FinishReading (CancellationToken cancellationToken)
+		{
+			/*
+			 * Call FinishReading() on the original inner stream.
+			 * 
+			 * Since GZipStream/DeflateStream knows the exact number of
+			 * bytes that it wants to receive from it, it may not have
+			 * read the chunk trailer yet.
+			 */
+			if (OriginalInnerStream is WebReadStream innerReadStream)
+				return innerReadStream.FinishReading (cancellationToken);
+			return Task.CompletedTask;
+		}
+	}
+}
+