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