mcs/class/System.Net.Http/System.Net.Http/StreamContent.cs

   1 //
   2 // StreamContent.cs
   3 //
   4 // Authors:
   5 //      Marek Safar  <marek.safar@gmail.com>
   6 //
   7 // Copyright (C) 2011 Xamarin Inc (http://www.xamarin.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System.IO;
  30 using System.Threading;
  31 using System.Threading.Tasks;
  32
  33 namespace System.Net.Http
  34 {
  35         public class StreamContent : HttpContent
  36         {
  37                 readonly Stream content;
  38                 readonly int bufferSize;
  39                 readonly CancellationToken cancellationToken;
  40                 readonly long startPosition;
  41                 bool contentCopied;
  42
  43                 public StreamContent (Stream content)
  44                         : this (content, 16 * 1024)
  45                 {
  46                 }
  47
  48                 public StreamContent (Stream content, int bufferSize)
  49                 {
  50                         if (content == null)
  51                                 throw new ArgumentNullException ("content");
  52
  53                         if (bufferSize <= 0)
  54                                 throw new ArgumentOutOfRangeException ("bufferSize");
  55
  56                         this.content = content;
  57                         this.bufferSize = bufferSize;
  58
  59                         if (content.CanSeek) {
  60                                 startPosition = content.Position;
  61                         }
  62                 }
  63
  64                 //
  65                 // Workarounds for poor .NET API
  66                 // Instead of having SerializeToStreamAsync with CancellationToken as public API. Only LoadIntoBufferAsync
  67                 // called internally from the send worker can be cancelled and user cannot see/do it
  68                 //
  69                 internal StreamContent (Stream content, CancellationToken cancellationToken)
  70                         : this (content)
  71                 {
  72                         // We don't own the token so don't worry about disposing it
  73                         this.cancellationToken = cancellationToken;
  74                 }
  75
  76                 protected override Task<Stream> CreateContentReadStreamAsync ()
  77                 {
  78                         return Task.FromResult (content);
  79                 }
  80
  81                 protected override void Dispose (bool disposing)
  82                 {
  83                         if (disposing) {
  84                                 content.Dispose ();
  85                         }
  86
  87                         base.Dispose (disposing);
  88                 }
  89
  90                 protected internal override Task SerializeToStreamAsync (Stream stream, TransportContext context)
  91                 {
  92                         if (contentCopied) {
  93                                 if (!content.CanSeek) {
  94                                         throw new InvalidOperationException ("The stream was already consumed. It cannot be read again.");
  95                                 }
  96
  97                                 content.Seek (startPosition, SeekOrigin.Begin);
  98                         } else {
  99                                 contentCopied = true;
 100                         }
 101
 102                         return content.CopyToAsync (stream, bufferSize, cancellationToken);
 103                 }
 104
 105                 protected internal override bool TryComputeLength (out long length)
 106                 {
 107                         if (!content.CanSeek) {
 108                                 length = 0;
 109                                 return false;
 110                         }
 111                         length = content.Length - startPosition;
 112                         return true;
 113                 }
 114         }
 115 }