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

   1 //
   2 // MemoryMappedViewAccessor.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 System.Collections.Generic;
  34 using Microsoft.Win32.SafeHandles;
  35 using Mono.Unix.Native;
  36
  37 namespace System.IO.MemoryMappedFiles
  38 {
  39         public sealed class MemoryMappedViewAccessor : UnmanagedMemoryAccessor, IDisposable {
  40                 int file_handle;
  41                 IntPtr mmap_addr;
  42                 SafeMemoryMappedViewHandle handle;
  43
  44                 internal MemoryMappedViewAccessor (int file_handle, long offset, long size, MemoryMappedFileAccess access)
  45                 {
  46                         this.file_handle = file_handle;
  47                         if (MonoUtil.IsUnix)
  48                                 CreatePosix (offset, size, access);
  49                         else
  50                                 throw new NotImplementedException ("Not implemented on windows.");
  51                 }
  52
  53                 static FileAccess ToFileAccess (MemoryMappedFileAccess access)
  54                 {
  55                         switch (access){
  56                         case MemoryMappedFileAccess.CopyOnWrite:
  57                         case MemoryMappedFileAccess.ReadWrite:
  58                         case MemoryMappedFileAccess.ReadWriteExecute:
  59                                 return FileAccess.ReadWrite;
  60                                 break;
  61
  62                         case MemoryMappedFileAccess.Write:
  63                                 return FileAccess.Write;
  64
  65                         case MemoryMappedFileAccess.ReadExecute:
  66                         case MemoryMappedFileAccess.Read:
  67                         default:
  68                                 return FileAccess.Read;
  69                         }
  70                 }
  71
  72                 unsafe void CreatePosix (long offset, long size, MemoryMappedFileAccess access)
  73                 {
  74                         int offset_diff;
  75
  76                         MemoryMappedFile.MapPosix (file_handle, offset, ref size, access, out mmap_addr, out offset_diff);
  77
  78                         handle = new SafeMemoryMappedViewHandle ((IntPtr)((long)mmap_addr + offset_diff), size);
  79                         Initialize (handle, 0, size, ToFileAccess (access));
  80                 }
  81
  82                 public SafeMemoryMappedViewHandle SafeMemoryMappedViewHandle {
  83                         get {
  84                                 return handle;
  85                         }
  86                 }
  87
  88                 protected override void Dispose (bool disposing)
  89                 {
  90                         base.Dispose (disposing);
  91                 }
  92
  93                 void IDisposable.Dispose () {
  94                         Dispose (true);
  95                 }
  96
  97                 public void Flush ()
  98                 {
  99                         if (MonoUtil.IsUnix)
 100                                 Syscall.fsync (file_handle);
 101                         else
 102                                 throw new NotImplementedException ("Not implemented on Windows");
 103                 }
 104         }
 105 }
 106
 107 #endif