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 #if NET_2_0
  39         public sealed class ExecutionContext : ISerializable {
  40 #else
  41         internal sealed class ExecutionContext : ISerializable {
  42 #endif
  43 #if !NET_2_1 || MONOTOUCH
  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 !NET_2_1 || MONOTOUCH
  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 !NET_2_1 || MONOTOUCH
  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                 [MonoTODO]
  92                 [ReflectionPermission (SecurityAction.Demand, MemberAccess = true)]
  93                 public void GetObjectData (SerializationInfo info, StreamingContext context)
  94                 {
  95                         if (info == null)
  96                                 throw new ArgumentNullException ("info");
  97                         throw new NotImplementedException ();
  98                 }
  99
 100                 // internal stuff
 101 #if !NET_2_1 || MONOTOUCH
 102                 internal SecurityContext SecurityContext {
 103                         get {
 104                                 if (_sc == null)
 105                                         _sc = new SecurityContext ();
 106                                 return _sc;
 107                         }
 108                         set { _sc = value; }
 109                 }
 110 #endif
 111                 internal bool FlowSuppressed {
 112                         get { return _suppressFlow; }
 113                         set { _suppressFlow = value; }
 114                 }
 115
 116                 // Note: Previous to version 2.0 only the CompressedStack and (sometimes!) the WindowsIdentity
 117                 // were propagated to new threads. This is why ExecutionContext is internal in before NET_2_0.
 118                 // It also means that all newer context classes should be here (i.e. inside the #if NET_2_0).
 119
 120                 public static bool IsFlowSuppressed ()
 121                 {
 122                         return Thread.CurrentThread.ExecutionContext.FlowSuppressed;
 123                 }
 124
 125                 public static void RestoreFlow ()
 126                 {
 127                         ExecutionContext ec = Thread.CurrentThread.ExecutionContext;
 128                         if (!ec.FlowSuppressed)
 129                                 throw new InvalidOperationException ();
 130
 131                         ec.FlowSuppressed = false;
 132                 }
 133 #if NET_2_0 && (!NET_2_1 || MONOTOUCH)
 134                 [MonoTODO ("only the SecurityContext is considered")]
 135                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 136                 public static void Run (ExecutionContext executionContext, ContextCallback callback, object state)
 137                 {
 138                         if (executionContext == null) {
 139                                 throw new InvalidOperationException (Locale.GetText (
 140                                         "Null ExecutionContext"));
 141                         }
 142
 143                         // FIXME: supporting more than one context (the SecurityContext)
 144                         // will requires a rewrite of this method
 145
 146                         SecurityContext.Run (executionContext.SecurityContext, callback, state);
 147                 }
 148 #endif
 149 #if !NET_2_1 || MONOTOUCH
 150                 public static AsyncFlowControl SuppressFlow ()
 151                 {
 152                         Thread t = Thread.CurrentThread;
 153                         t.ExecutionContext.FlowSuppressed = true;
 154                         return new AsyncFlowControl (t, AsyncFlowControlType.Execution);
 155                 }
 156 #endif
 157         }
 158 }