1 #region Copyright notice and license 2 // Protocol Buffers - Google's data interchange format 3 // Copyright 2008 Google Inc. All rights reserved. 4 // 5 // Use of this source code is governed by a BSD-style 6 // license that can be found in the LICENSE file or at 7 // https://developers.google.com/open-source/licenses/bsd 8 #endregion 9 10 using System; 11 using System.IO; 12 using System.Threading; 13 using System.Threading.Tasks; 14 15 namespace Google.Protobuf 16 { 17 /// <summary> 18 /// SecuritySafeCritical attribute can not be placed on types with async methods. 19 /// This class has ByteString's async methods so it can be marked with SecuritySafeCritical. 20 /// </summary> 21 internal static class ByteStringAsync 22 { FromStreamAsyncCore(Stream stream, CancellationToken cancellationToken)23 internal static async Task<ByteString> FromStreamAsyncCore(Stream stream, CancellationToken cancellationToken) 24 { 25 int capacity = stream.CanSeek ? checked((int)(stream.Length - stream.Position)) : 0; 26 var memoryStream = new MemoryStream(capacity); 27 // We have to specify the buffer size here, as there's no overload accepting the cancellation token 28 // alone. But it's documented to use 81920 by default if not specified. 29 await stream.CopyToAsync(memoryStream, 81920, cancellationToken); 30 #if NETSTANDARD1_1 31 byte[] bytes = memoryStream.ToArray(); 32 #else 33 // Avoid an extra copy if we can. 34 byte[] bytes = memoryStream.Length == memoryStream.Capacity ? memoryStream.GetBuffer() : memoryStream.ToArray(); 35 #endif 36 return ByteString.AttachBytes(bytes); 37 } 38 } 39 }