mcs/class/System/System.Threading/Semaphore.cs

   1 //
   2 // System.Threading.Semaphore.cs
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // Copyright (C) 2005 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 using System.Runtime.ConstrainedExecution;
  30 using System.Runtime.InteropServices;
  31 using System.Security.AccessControl;
  32 using System.Security.Permissions;
  33 using System.Runtime.CompilerServices;
  34 using System.IO;
  35
  36 namespace System.Threading {
  37
  38         [ComVisible (false)]
  39         public sealed class Semaphore : WaitHandle {
  40
  41                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  42                 private static extern IntPtr CreateSemaphore_internal (
  43                         int initialCount, int maximumCount, string name,
  44                         out bool createdNew);
  45
  46                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  47                 private static extern int ReleaseSemaphore_internal (
  48                         IntPtr handle, int releaseCount, out bool fail);
  49
  50                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  51                 private static extern IntPtr OpenSemaphore_internal (string name, SemaphoreRights rights, out MonoIOError error);
  52
  53                 private Semaphore (IntPtr handle)
  54                 {
  55                         Handle = handle;
  56                 }
  57
  58                 public Semaphore (int initialCount, int maximumCount)
  59                         : this (initialCount, maximumCount, null)
  60                 {
  61                 }
  62
  63                 public Semaphore (int initialCount, int maximumCount, string name)
  64                 {
  65                         if (initialCount < 0)
  66                                 throw new ArgumentOutOfRangeException ("initialCount", "< 0");
  67                         if (maximumCount < 1)
  68                                 throw new ArgumentOutOfRangeException ("maximumCount", "< 1");
  69                         if (initialCount > maximumCount)
  70                                 throw new ArgumentException ("initialCount > maximumCount");
  71
  72                         bool created;
  73
  74                         Handle = CreateSemaphore_internal (initialCount,
  75                                                            maximumCount, name,
  76                                                            out created);
  77                 }
  78
  79                 public Semaphore (int initialCount, int maximumCount, string name, out bool createdNew)
  80                         : this (initialCount, maximumCount, name, out createdNew, null)
  81                 {
  82                 }
  83
  84                 [MonoTODO ("CreateSemaphore_internal does not support access control, semaphoreSecurity is ignored")]
  85                 public Semaphore (int initialCount, int maximumCount, string name, out bool createdNew,
  86                         SemaphoreSecurity semaphoreSecurity)
  87                 {
  88                         if (initialCount < 0)
  89                                 throw new ArgumentOutOfRangeException ("initialCount", "< 0");
  90                         if (maximumCount < 1)
  91                                 throw new ArgumentOutOfRangeException ("maximumCount", "< 1");
  92                         if (initialCount > maximumCount)
  93                                 throw new ArgumentException ("initialCount > maximumCount");
  94
  95                         Handle = CreateSemaphore_internal (initialCount,
  96                                                            maximumCount, name,
  97                                                            out createdNew);
  98                 }
  99
 100                 public SemaphoreSecurity GetAccessControl ()
 101                 {
 102                         return new SemaphoreSecurity (SafeWaitHandle,
 103                                                       AccessControlSections.Owner |
 104                                                       AccessControlSections.Group |
 105                                                       AccessControlSections.Access);
 106                 }
 107
 108                 [PrePrepareMethod]
 109                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.Success)]
 110                 public int Release ()
 111                 {
 112                         return (Release (1));
 113                 }
 114
 115                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.Success)]
 116                 public int Release (int releaseCount)
 117                 {
 118                         if (releaseCount < 1)
 119                                 throw new ArgumentOutOfRangeException ("releaseCount");
 120
 121                         int ret;
 122                         bool fail;
 123
 124                         ret = ReleaseSemaphore_internal (Handle, releaseCount,
 125                                                          out fail);
 126
 127                         if (fail) {
 128                                 throw new SemaphoreFullException ();
 129                         }
 130
 131                         return (ret);
 132                 }
 133
 134                 public void SetAccessControl (SemaphoreSecurity semaphoreSecurity)
 135                 {
 136                         if (semaphoreSecurity == null)
 137                                 throw new ArgumentNullException ("semaphoreSecurity");
 138
 139                         semaphoreSecurity.PersistModifications (SafeWaitHandle);
 140                 }
 141
 142                 // static methods
 143
 144 #if !MOBILE
 145                 public static Semaphore OpenExisting (string name)
 146                 {
 147                         return OpenExisting (name, SemaphoreRights.Synchronize | SemaphoreRights.Modify);
 148                 }
 149
 150                 public static Semaphore OpenExisting (string name, SemaphoreRights rights)
 151                 {
 152                         if (name == null)
 153                                 throw new ArgumentNullException ("name");
 154                         if ((name.Length ==0) || (name.Length > 260))
 155                                 throw new ArgumentException ("name", Locale.GetText ("Invalid length [1-260]."));
 156
 157                         MonoIOError error;
 158                         IntPtr handle = OpenSemaphore_internal (name, rights,
 159                                                                 out error);
 160                         if (handle == (IntPtr)null) {
 161                                 if (error == MonoIOError.ERROR_FILE_NOT_FOUND) {
 162                                         throw new WaitHandleCannotBeOpenedException (Locale.GetText ("Named Semaphore handle does not exist: ") + name);
 163                                 } else if (error == MonoIOError.ERROR_ACCESS_DENIED) {
 164                                         throw new UnauthorizedAccessException ();
 165                                 } else {
 166                                         throw new IOException (Locale.GetText ("Win32 IO error: ") + error.ToString ());
 167                                 }
 168                         }
 169
 170                         return(new Semaphore (handle));
 171                 }
 172
 173                 [SecurityPermissionAttribute (SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
 174                 public static bool TryOpenExisting (string name, out Semaphore result)
 175                 {
 176                         return TryOpenExisting (name, SemaphoreRights.Synchronize | SemaphoreRights.Modify, out result);
 177                 }
 178
 179                 [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
 180                 public static bool TryOpenExisting (string name, SemaphoreRights rights, out Semaphore result)
 181                 {
 182                         if (name == null)
 183                                 throw new ArgumentNullException ("name");
 184                         if ((name.Length == 0) || (name.Length > 260))
 185                                 throw new ArgumentException ("name", Locale.GetText ("Invalid length [1-260]."));
 186
 187                         MonoIOError error;
 188                         IntPtr handle = OpenSemaphore_internal (name, rights, out error);
 189
 190                         if (handle == (IntPtr)null) {
 191                                 result = null;
 192                                 return false;
 193                         }
 194
 195                         result = new Semaphore (handle);
 196                         return true;
 197                 }
 198 #else
 199                 public static Semaphore OpenExisting (string name)
 200                 {
 201                         throw new NotSupportedException ();
 202                 }
 203
 204                 public static Semaphore OpenExisting (string name, SemaphoreRights rights)
 205                 {
 206                         throw new NotSupportedException ();
 207                 }
 208
 209                 public static bool TryOpenExisting (string name, out Semaphore result)
 210                 {
 211                         throw new NotSupportedException ();
 212                 }
 213
 214                 public static bool TryOpenExisting (string name, SemaphoreRights rights, out Semaphore result)
 215                 {
 216                         throw new NotSupportedException ();
 217                 }
 218 #endif
 219         }
 220 }
 221