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 !MOONLIGHT
  40                 private SecurityContext _sc;
  41 #endif
  42                 private bool _suppressFlow;
  43                 private bool _capture;
  44
  45                 internal ExecutionContext ()
  46                 {
  47                 }
  48
  49                 internal ExecutionContext (ExecutionContext ec)
  50                 {
  51 #if !MOONLIGHT
  52                         if (ec._sc != null)
  53                                 _sc = new SecurityContext (ec._sc);
  54 #endif
  55                         _suppressFlow = ec._suppressFlow;
  56                         _capture = true;
  57                 }
  58
  59                 [MonoTODO]
  60                 internal ExecutionContext (SerializationInfo info, StreamingContext context)
  61                 {
  62                         throw new NotImplementedException ();
  63                 }
  64
  65                 public static ExecutionContext Capture ()
  66                 {
  67                         ExecutionContext ec = Thread.CurrentThread.ExecutionContext;
  68                         if (ec.FlowSuppressed)
  69                                 return null;
  70
  71                         ExecutionContext capture = new ExecutionContext (ec);
  72 #if !MOONLIGHT
  73                         if (SecurityManager.SecurityEnabled)
  74                                 capture.SecurityContext = SecurityContext.Capture ();
  75 #endif
  76                         return capture;
  77                 }
  78
  79                 public ExecutionContext CreateCopy ()
  80                 {
  81                         if (!_capture)
  82                                 throw new InvalidOperationException ();
  83
  84                         return new ExecutionContext (this);
  85                 }
  86
  87                 [MonoTODO]
  88                 [ReflectionPermission (SecurityAction.Demand, MemberAccess = true)]
  89                 public void GetObjectData (SerializationInfo info, StreamingContext context)
  90                 {
  91                         if (info == null)
  92                                 throw new ArgumentNullException ("info");
  93                         throw new NotImplementedException ();
  94                 }
  95
  96                 // internal stuff
  97 #if !MOONLIGHT
  98                 internal SecurityContext SecurityContext {
  99                         get {
 100                                 if (_sc == null)
 101                                         _sc = new SecurityContext ();
 102                                 return _sc;
 103                         }
 104                         set { _sc = value; }
 105                 }
 106 #endif
 107                 internal bool FlowSuppressed {
 108                         get { return _suppressFlow; }
 109                         set { _suppressFlow = value; }
 110                 }
 111
 112                 // Note: Previous to version 2.0 only the CompressedStack and (sometimes!) the WindowsIdentity
 113                 // were propagated to new threads. This is why ExecutionContext is internal in before NET_2_0.
 114                 // It also means that all newer context classes should be here (i.e. inside the #if NET_2_0).
 115
 116                 public static bool IsFlowSuppressed ()
 117                 {
 118                         return Thread.CurrentThread.ExecutionContext.FlowSuppressed;
 119                 }
 120
 121                 public static void RestoreFlow ()
 122                 {
 123                         ExecutionContext ec = Thread.CurrentThread.ExecutionContext;
 124                         if (!ec.FlowSuppressed)
 125                                 throw new InvalidOperationException ();
 126
 127                         ec.FlowSuppressed = false;
 128                 }
 129
 130 #if !MOONLIGHT
 131                 [MonoTODO ("only the SecurityContext is considered")]
 132                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 133                 public static void Run (ExecutionContext executionContext, ContextCallback callback, object state)
 134                 {
 135                         if (executionContext == null) {
 136                                 throw new InvalidOperationException (Locale.GetText (
 137                                         "Null ExecutionContext"));
 138                         }
 139
 140                         // FIXME: supporting more than one context (the SecurityContext)
 141                         // will requires a rewrite of this method
 142
 143                         SecurityContext.Run (executionContext.SecurityContext, callback, state);
 144                 }
 145
 146                 public static AsyncFlowControl SuppressFlow ()
 147                 {
 148                         Thread t = Thread.CurrentThread;
 149                         t.ExecutionContext.FlowSuppressed = true;
 150                         return new AsyncFlowControl (t, AsyncFlowControlType.Execution);
 151                 }
 152 #endif
 153         }
 154 }