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 //  Marek Safar (marek.safar@gmail.com)
   8 //
   9 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  10 // Copyright (C) 2014 Xamarin Inc (http://www.xamarin.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Runtime.InteropServices;
  33 using System.Runtime.Serialization;
  34 using System.Security;
  35 using System.Security.Permissions;
  36 using System.Runtime.Remoting.Messaging;
  37 using System.Collections.Generic;
  38
  39 namespace System.Threading {
  40         [Serializable]
  41         public sealed partial class ExecutionContext : ISerializable
  42            , IDisposable
  43         {
  44                 internal struct Switcher
  45                 {
  46                         readonly ExecutionContext ec;
  47                         readonly LogicalCallContext _lcc;
  48                         readonly bool _suppressFlow;
  49                         readonly bool _capture;
  50                         readonly Dictionary<string, object> local_data;
  51                         readonly bool copy_on_write;
  52
  53                         public Switcher (ExecutionContext ec)
  54                         {
  55                                 this.ec = ec;
  56                                 this._lcc = ec._lcc;
  57                                 this._suppressFlow = ec._suppressFlow;
  58                                 this._capture = ec._capture;
  59                                 this.local_data = ec.local_data;
  60                                 this.copy_on_write = ec.CopyOnWrite;
  61                         }
  62
  63                         public bool IsEmpty {
  64                                 get {
  65                                         return ec == null;
  66                                 }
  67                         }
  68
  69                         public void Restore (ExecutionContext ec)
  70                         {
  71                                 ec._lcc = this._lcc;
  72                                 ec._suppressFlow = this._suppressFlow;
  73                                 ec._capture = this._capture;
  74                                 ec.local_data = this.local_data;
  75                                 ec.CopyOnWrite = this.copy_on_write;
  76                         }
  77                 }
  78
  79 #if !MOBILE
  80                 private SecurityContext _sc;
  81 #endif
  82                 private LogicalCallContext _lcc;
  83                 private bool _suppressFlow;
  84                 private bool _capture;
  85                 Dictionary<string, object> local_data;
  86
  87                 internal ExecutionContext ()
  88                 {
  89                 }
  90
  91                 private ExecutionContext (ExecutionContext ec)
  92                 {
  93                         CloneData (ec);
  94
  95                         _suppressFlow = ec._suppressFlow;
  96                         _capture = true;
  97                 }
  98
  99                 void CloneData (ExecutionContext ec)
 100                 {
 101 #if !MOBILE
 102                         if (ec._sc != null)
 103                                 _sc = new SecurityContext (ec._sc);
 104 #endif
 105                         if (ec._lcc != null)
 106                                 _lcc = (LogicalCallContext) ec._lcc.Clone ();
 107                 }
 108
 109                 [MonoTODO]
 110                 internal ExecutionContext (SerializationInfo info, StreamingContext context)
 111                 {
 112                         throw new NotImplementedException ();
 113                 }
 114
 115                 public static ExecutionContext Capture ()
 116                 {
 117                         return Capture (true, false);
 118                 }
 119
 120                 internal static ExecutionContext Capture (bool captureSyncContext, bool nullOnEmpty)
 121                 {
 122                         var thread = Thread.CurrentThread;
 123                         if (nullOnEmpty && !thread.HasExecutionContext)
 124                                 return null;
 125
 126                         var ec = thread.ExecutionContext;
 127                         if (ec.FlowSuppressed)
 128                                 return null;
 129
 130                         if (nullOnEmpty
 131 #if !MOBILE
 132                          && ec._sc == null
 133 #endif
 134                                 && (ec._lcc == null || !ec._lcc.HasInfo))
 135                                 return null;
 136
 137                         ExecutionContext capture = new ExecutionContext (ec);
 138 #if !MOBILE
 139                         if (SecurityManager.SecurityEnabled)
 140                                 capture.SecurityContext = SecurityContext.Capture ();
 141 #endif
 142                         return capture;
 143                 }
 144
 145                 public ExecutionContext CreateCopy ()
 146                 {
 147                         if (!_capture)
 148                                 throw new InvalidOperationException ();
 149
 150                         return new ExecutionContext (this);
 151                 }
 152
 153                 public void Dispose ()
 154                 {
 155 #if !MOBILE
 156                         if (_sc != null)
 157                                 _sc.Dispose ();
 158 #endif
 159                 }
 160
 161                 [MonoTODO]
 162                 [ReflectionPermission (SecurityAction.Demand, MemberAccess = true)]
 163                 public void GetObjectData (SerializationInfo info, StreamingContext context)
 164                 {
 165                         if (info == null)
 166                                 throw new ArgumentNullException ("info");
 167                         throw new NotImplementedException ();
 168                 }
 169
 170                 // internal stuff
 171
 172                 internal LogicalCallContext LogicalCallContext {
 173                         get {
 174                                 if (_lcc == null)
 175                                         _lcc = new LogicalCallContext ();
 176                                 return _lcc;
 177                         }
 178                         set {
 179                                 _lcc = value;
 180                         }
 181                 }
 182
 183                 internal Dictionary<string, object> DataStore {
 184                         get {
 185                                 if (local_data == null)
 186                                         local_data = new Dictionary<string, object> ();
 187                                 return local_data;
 188                         }
 189                         set {
 190                                 local_data = value;
 191                         }
 192                 }
 193
 194 #if !MOBILE
 195                 internal SecurityContext SecurityContext {
 196                         get {
 197                                 if (_sc == null)
 198                                         _sc = new SecurityContext ();
 199                                 return _sc;
 200                         }
 201                         set { _sc = value; }
 202                 }
 203 #endif
 204
 205                 internal bool FlowSuppressed {
 206                         get { return _suppressFlow; }
 207                         set { _suppressFlow = value; }
 208                 }
 209
 210                 internal bool CopyOnWrite { get; set; }
 211
 212                 public static bool IsFlowSuppressed ()
 213                 {
 214                         return Current.FlowSuppressed;
 215                 }
 216
 217                 public static void RestoreFlow ()
 218                 {
 219                         ExecutionContext ec = Current;
 220                         if (!ec.FlowSuppressed)
 221                                 throw new InvalidOperationException ();
 222
 223                         ec.FlowSuppressed = false;
 224                 }
 225
 226                 internal static void Run(ExecutionContext executionContext, ContextCallback callback, Object state, bool preserveSyncCtx)
 227                 {
 228                         Run (executionContext, callback, state);
 229                 }
 230
 231                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 232                 public static void Run (ExecutionContext executionContext, ContextCallback callback, object state)
 233                 {
 234                         if (executionContext == null) {
 235                                 throw new InvalidOperationException (Locale.GetText (
 236                                         "Null ExecutionContext"));
 237                         }
 238
 239                         var prev = Current;
 240                         try {
 241                                 Thread.CurrentThread.ExecutionContext = executionContext;
 242                                 callback (state);
 243                         } finally {
 244                                 Thread.CurrentThread.ExecutionContext = prev;
 245                         }
 246                 }
 247
 248                 public static AsyncFlowControl SuppressFlow ()
 249                 {
 250                         Thread t = Thread.CurrentThread;
 251                         t.ExecutionContext.FlowSuppressed = true;
 252                         return new AsyncFlowControl (t, AsyncFlowControlType.Execution);
 253                 }
 254
 255                 internal static LogicalCallContext CreateLogicalCallContext (bool createEmpty)
 256                 {
 257                         var lcc = Current._lcc;
 258                         if (lcc == null) {
 259                                 if (createEmpty)
 260                                         lcc = new LogicalCallContext ();
 261
 262                                 return lcc;
 263                         }
 264
 265                         return (LogicalCallContext) lcc.Clone ();
 266                 }
 267
 268                 internal void FreeNamedDataSlot (string name)
 269                 {
 270                         if (_lcc != null)
 271                                 _lcc.FreeNamedDataSlot (name);
 272
 273                         if (local_data != null)
 274                                 local_data.Remove (name);
 275                 }
 276
 277                 internal static ExecutionContext Current {
 278                         get {
 279                                 return Thread.CurrentThread.ExecutionContext;
 280                         }
 281                 }
 282
 283                 internal static ExecutionContext GetCurrentWritable ()
 284                 {
 285                         var current = Thread.CurrentThread.ExecutionContext;
 286                         if (current.CopyOnWrite) {
 287                                 current.CopyOnWrite = false;
 288                                 current.CloneData (current);
 289                         }
 290
 291                         return current;
 292                 }
 293         }
 294 }