class/System.Core/System.IO.MemoryMappedFiles/MemoryMappedViewStream.cs

   1 //
   2 // MemoryMappedViewStream.cs
   3 //
   4 // Authors:
   5 //      Zoltan Varga (vargaz@gmail.com)
   6 //
   7 // Copyright (C) 2009, Novell, Inc (http://www.novell.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 #if NET_4_0
  30
  31 using System;
  32 using System.IO;
  33 using Mono.Unix.Native;
  34
  35 namespace System.IO.MemoryMappedFiles
  36 {
  37         public sealed class MemoryMappedViewStream : UnmanagedMemoryStream {
  38                 IntPtr mmap_addr;
  39                 ulong mmap_size;
  40                 object monitor;
  41                 int fd;
  42
  43                 internal MemoryMappedViewStream (int fd, long offset, long size, MemoryMappedFileAccess access) {
  44                         this.fd = fd;
  45                         monitor = new Object ();
  46                         if (MonoUtil.IsUnix)
  47                                 CreateStreamPosix (fd, offset, size, access);
  48                         else
  49                                 throw new NotImplementedException ("Not implemented on windows.");
  50                 }
  51
  52                 unsafe void CreateStreamPosix (int fd, long offset, long size, MemoryMappedFileAccess access)
  53                 {
  54                         int offset_diff;
  55                         mmap_size = (ulong) size;
  56                         MemoryMappedFile.MapPosix (fd, offset, ref size, access, out mmap_addr, out offset_diff);
  57                         FileAccess faccess;
  58
  59                         switch (access) {
  60                         case MemoryMappedFileAccess.ReadWrite:
  61                                 faccess = FileAccess.ReadWrite;
  62                                 break;
  63                         case MemoryMappedFileAccess.Read:
  64                                 faccess = FileAccess.Read;
  65                                 break;
  66                         case MemoryMappedFileAccess.Write:
  67                                 faccess = FileAccess.Write;
  68                                 break;
  69                         default:
  70                                 throw new NotImplementedException ("access mode " + access + " not supported.");
  71                         }
  72                         Initialize ((byte*)mmap_addr + offset_diff, size, size, faccess);
  73                 }
  74
  75                 protected override void Dispose (bool disposing)
  76                 {
  77                         base.Dispose (disposing);
  78                         lock (monitor) {
  79                                 if (mmap_addr != (IntPtr)(-1)) {
  80                                         MemoryMappedFile.UnmapPosix (mmap_addr, mmap_size);
  81                                         mmap_addr = (IntPtr)(-1);
  82                                 }
  83                         }
  84                 }
  85
  86                 public override void Flush ()
  87                 {
  88                         if (MonoUtil.IsUnix)
  89                                 Syscall.fsync (fd);
  90                         else
  91                                 throw new NotImplementedException ("Not implemented on Windows");
  92                 }
  93         }
  94 }
  95
  96 #endif