mcs/class/corlib/System.Threading/ExecutionContext.cs

   1 //
   2 // System.Threading.ExecutionContext.cs
   3 //
   4 // Authors:
   5 //      Lluis Sanchez (lluis@novell.com)
   6 //      Sebastien Pouliot  <sebastien@ximian.com>
   7 //
   8 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System.Runtime.InteropServices;
  31 using System.Runtime.Serialization;
  32 using System.Security;
  33 using System.Security.Permissions;
  34
  35 namespace System.Threading {
  36
  37         [Serializable]
  38         public sealed class ExecutionContext : ISerializable
  39 #if NET_4_0
  40                 , IDisposable
  41 #endif
  42         {
  43 #if !MOONLIGHT
  44                 private SecurityContext _sc;
  45 #endif
  46                 private bool _suppressFlow;
  47                 private bool _capture;
  48
  49                 internal ExecutionContext ()
  50                 {
  51                 }
  52
  53                 internal ExecutionContext (ExecutionContext ec)
  54                 {
  55 #if !MOONLIGHT
  56                         if (ec._sc != null)
  57                                 _sc = new SecurityContext (ec._sc);
  58 #endif
  59                         _suppressFlow = ec._suppressFlow;
  60                         _capture = true;
  61                 }
  62
  63                 [MonoTODO]
  64                 internal ExecutionContext (SerializationInfo info, StreamingContext context)
  65                 {
  66                         throw new NotImplementedException ();
  67                 }
  68
  69                 public static ExecutionContext Capture ()
  70                 {
  71                         ExecutionContext ec = Thread.CurrentThread.ExecutionContext;
  72                         if (ec.FlowSuppressed)
  73                                 return null;
  74
  75                         ExecutionContext capture = new ExecutionContext (ec);
  76 #if !MOONLIGHT
  77                         if (SecurityManager.SecurityEnabled)
  78                                 capture.SecurityContext = SecurityContext.Capture ();
  79 #endif
  80                         return capture;
  81                 }
  82
  83                 public ExecutionContext CreateCopy ()
  84                 {
  85                         if (!_capture)
  86                                 throw new InvalidOperationException ();
  87
  88                         return new ExecutionContext (this);
  89                 }
  90
  91 #if NET_4_0
  92                 public void Dispose ()
  93                 {
  94                         if (_sc != null)
  95                                 _sc.Dispose ();
  96                 }
  97 #endif
  98
  99                 [MonoTODO]
 100                 [ReflectionPermission (SecurityAction.Demand, MemberAccess = true)]
 101                 public void GetObjectData (SerializationInfo info, StreamingContext context)
 102                 {
 103                         if (info == null)
 104                                 throw new ArgumentNullException ("info");
 105                         throw new NotImplementedException ();
 106                 }
 107
 108                 // internal stuff
 109 #if !MOONLIGHT
 110                 internal SecurityContext SecurityContext {
 111                         get {
 112                                 if (_sc == null)
 113                                         _sc = new SecurityContext ();
 114                                 return _sc;
 115                         }
 116                         set { _sc = value; }
 117                 }
 118 #endif
 119                 internal bool FlowSuppressed {
 120                         get { return _suppressFlow; }
 121                         set { _suppressFlow = value; }
 122                 }
 123
 124                 // Note: Previous to version 2.0 only the CompressedStack and (sometimes!) the WindowsIdentity
 125                 // were propagated to new threads. This is why ExecutionContext is internal in before NET_2_0.
 126                 // It also means that all newer context classes should be here (i.e. inside the #if NET_2_0).
 127
 128                 public static bool IsFlowSuppressed ()
 129                 {
 130                         return Thread.CurrentThread.ExecutionContext.FlowSuppressed;
 131                 }
 132
 133                 public static void RestoreFlow ()
 134                 {
 135                         ExecutionContext ec = Thread.CurrentThread.ExecutionContext;
 136                         if (!ec.FlowSuppressed)
 137                                 throw new InvalidOperationException ();
 138
 139                         ec.FlowSuppressed = false;
 140                 }
 141
 142 #if !MOONLIGHT
 143                 [MonoTODO ("only the SecurityContext is considered")]
 144                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 145                 public static void Run (ExecutionContext executionContext, ContextCallback callback, object state)
 146                 {
 147                         if (executionContext == null) {
 148                                 throw new InvalidOperationException (Locale.GetText (
 149                                         "Null ExecutionContext"));
 150                         }
 151
 152                         // FIXME: supporting more than one context (the SecurityContext)
 153                         // will requires a rewrite of this method
 154
 155                         SecurityContext.Run (executionContext.SecurityContext, callback, state);
 156                 }
 157
 158                 public static AsyncFlowControl SuppressFlow ()
 159                 {
 160                         Thread t = Thread.CurrentThread;
 161                         t.ExecutionContext.FlowSuppressed = true;
 162                         return new AsyncFlowControl (t, AsyncFlowControlType.Execution);
 163                 }
 164 #endif
 165         }
 166 }