mcs/class/Mono.Profiler.Log/Mono.Profiler.Log/LogStream.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 using System;
   6 using System.IO;
   7
   8 namespace Mono.Profiler.Log {
   9
  10         public class LogStream : Stream {
  11
  12                 public Stream BaseStream { get; }
  13
  14                 public virtual bool EndOfStream => BaseStream.Position == BaseStream.Length;
  15
  16                 public override bool CanRead => true;
  17
  18                 public override bool CanSeek => false;
  19
  20                 public override bool CanWrite => false;
  21
  22                 public override long Length => throw new NotSupportedException ();
  23
  24                 public override long Position {
  25                         get => throw new NotSupportedException ();
  26                         set => throw new NotSupportedException ();
  27                 }
  28
  29                 readonly byte[] _byteBuffer = new byte [1];
  30
  31                 public LogStream (Stream baseStream)
  32                 {
  33                         if (baseStream == null)
  34                                 throw new ArgumentNullException (nameof (baseStream));
  35
  36                         if (!baseStream.CanRead)
  37                                 throw new ArgumentException ("Stream does not support reading.", nameof (baseStream));
  38
  39                         BaseStream = baseStream;
  40                 }
  41
  42                 protected override void Dispose (bool disposing)
  43                 {
  44                         if (disposing)
  45                                 BaseStream.Dispose ();
  46                 }
  47
  48                 public override void Flush ()
  49                 {
  50                         throw new NotSupportedException ();
  51                 }
  52
  53                 public override int ReadByte ()
  54                 {
  55                         // The base method on Stream is extremely inefficient in that it
  56                         // allocates a 1-byte array for every call. Simply use a private
  57                         // buffer instead.
  58                         return Read (_byteBuffer, 0, sizeof (byte)) == 0 ? -1 : _byteBuffer [0];
  59                 }
  60
  61                 public override int Read (byte[] buffer, int offset, int count)
  62                 {
  63                         return BaseStream.Read (buffer, offset, count);
  64                 }
  65
  66                 public override long Seek (long offset, SeekOrigin origin)
  67                 {
  68                         throw new NotSupportedException ();
  69                 }
  70
  71                 public override void SetLength (long value)
  72                 {
  73                         throw new NotSupportedException ();
  74                 }
  75
  76                 public override void Write (byte[] buffer, int offset, int count)
  77                 {
  78                         throw new NotSupportedException ();
  79                 }
  80         }
  81 }