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 #if NET_4_0
  43            , IDisposable
  44 #endif
  45         {
  46                 internal struct Switcher
  47                 {
  48                         readonly ExecutionContext ec;
  49                         readonly LogicalCallContext _lcc;
  50                         readonly bool _suppressFlow;
  51                         readonly bool _capture;
  52                         readonly Dictionary<string, object> local_data;
  53                         readonly bool copy_on_write;
  54
  55                         public Switcher (ExecutionContext ec)
  56                         {
  57                                 this.ec = ec;
  58                                 this._lcc = ec._lcc;
  59                                 this._suppressFlow = ec._suppressFlow;
  60                                 this._capture = ec._capture;
  61                                 this.local_data = ec.local_data;
  62                                 this.copy_on_write = ec.CopyOnWrite;
  63                         }
  64
  65                         public bool IsEmpty {
  66                                 get {
  67                                         return ec == null;
  68                                 }
  69                         }
  70
  71                         public void Restore (ExecutionContext ec)
  72                         {
  73                                 ec._lcc = this._lcc;
  74                                 ec._suppressFlow = this._suppressFlow;
  75                                 ec._capture = this._capture;
  76                                 ec.local_data = this.local_data;
  77                                 ec.CopyOnWrite = this.copy_on_write;
  78                         }
  79                 }
  80
  81 #if !MOBILE
  82                 private SecurityContext _sc;
  83 #endif
  84                 private LogicalCallContext _lcc;
  85                 private bool _suppressFlow;
  86                 private bool _capture;
  87                 Dictionary<string, object> local_data;
  88
  89                 internal ExecutionContext ()
  90                 {
  91                 }
  92
  93                 private ExecutionContext (ExecutionContext ec)
  94                 {
  95                         CloneData (ec);
  96
  97                         _suppressFlow = ec._suppressFlow;
  98                         _capture = true;
  99                 }
 100
 101                 void CloneData (ExecutionContext ec)
 102                 {
 103 #if !MOBILE
 104                         if (ec._sc != null)
 105                                 _sc = new SecurityContext (ec._sc);
 106 #endif
 107                         if (ec._lcc != null)
 108                                 _lcc = (LogicalCallContext) ec._lcc.Clone ();
 109                 }
 110
 111                 [MonoTODO]
 112                 internal ExecutionContext (SerializationInfo info, StreamingContext context)
 113                 {
 114                         throw new NotImplementedException ();
 115                 }
 116
 117                 public static ExecutionContext Capture ()
 118                 {
 119                         return Capture (true, false);
 120                 }
 121
 122                 internal static ExecutionContext Capture (bool captureSyncContext, bool nullOnEmpty)
 123                 {
 124                         var thread = Thread.CurrentThread;
 125                         if (nullOnEmpty && !thread.HasExecutionContext)
 126                                 return null;
 127
 128                         var ec = thread.ExecutionContext;
 129                         if (ec.FlowSuppressed)
 130                                 return null;
 131
 132                         if (nullOnEmpty
 133 #if !MOBILE
 134                          && ec._sc == null
 135 #endif
 136                                 && (ec._lcc == null || !ec._lcc.HasInfo))
 137                                 return null;
 138
 139                         ExecutionContext capture = new ExecutionContext (ec);
 140 #if !MOBILE
 141                         if (SecurityManager.SecurityEnabled)
 142                                 capture.SecurityContext = SecurityContext.Capture ();
 143 #endif
 144                         return capture;
 145                 }
 146
 147                 public ExecutionContext CreateCopy ()
 148                 {
 149                         if (!_capture)
 150                                 throw new InvalidOperationException ();
 151
 152                         return new ExecutionContext (this);
 153                 }
 154
 155 #if NET_4_0
 156                 public void Dispose ()
 157                 {
 158 #if !MOBILE
 159                         if (_sc != null)
 160                                 _sc.Dispose ();
 161 #endif
 162                 }
 163 #endif
 164
 165                 [MonoTODO]
 166                 [ReflectionPermission (SecurityAction.Demand, MemberAccess = true)]
 167                 public void GetObjectData (SerializationInfo info, StreamingContext context)
 168                 {
 169                         if (info == null)
 170                                 throw new ArgumentNullException ("info");
 171                         throw new NotImplementedException ();
 172                 }
 173
 174                 // internal stuff
 175
 176                 internal LogicalCallContext LogicalCallContext {
 177                         get {
 178                                 if (_lcc == null)
 179                                         _lcc = new LogicalCallContext ();
 180                                 return _lcc;
 181                         }
 182                         set {
 183                                 _lcc = value;
 184                         }
 185                 }
 186
 187                 internal Dictionary<string, object> DataStore {
 188                         get {
 189                                 if (local_data == null)
 190                                         local_data = new Dictionary<string, object> ();
 191                                 return local_data;
 192                         }
 193                         set {
 194                                 local_data = value;
 195                         }
 196                 }
 197
 198 #if !MOBILE
 199                 internal SecurityContext SecurityContext {
 200                         get {
 201                                 if (_sc == null)
 202                                         _sc = new SecurityContext ();
 203                                 return _sc;
 204                         }
 205                         set { _sc = value; }
 206                 }
 207 #endif
 208
 209                 internal bool FlowSuppressed {
 210                         get { return _suppressFlow; }
 211                         set { _suppressFlow = value; }
 212                 }
 213
 214                 internal bool CopyOnWrite { get; set; }
 215
 216                 public static bool IsFlowSuppressed ()
 217                 {
 218                         return Current.FlowSuppressed;
 219                 }
 220
 221                 public static void RestoreFlow ()
 222                 {
 223                         ExecutionContext ec = Current;
 224                         if (!ec.FlowSuppressed)
 225                                 throw new InvalidOperationException ();
 226
 227                         ec.FlowSuppressed = false;
 228                 }
 229
 230                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 231                 public static void Run (ExecutionContext executionContext, ContextCallback callback, object state)
 232                 {
 233                         if (executionContext == null) {
 234                                 throw new InvalidOperationException (Locale.GetText (
 235                                         "Null ExecutionContext"));
 236                         }
 237
 238                         var prev = Current;
 239                         try {
 240                                 Thread.CurrentThread.ExecutionContext = executionContext;
 241                                 callback (state);
 242                         } finally {
 243                                 Thread.CurrentThread.ExecutionContext = prev;
 244                         }
 245                 }
 246
 247                 public static AsyncFlowControl SuppressFlow ()
 248                 {
 249                         Thread t = Thread.CurrentThread;
 250                         t.ExecutionContext.FlowSuppressed = true;
 251                         return new AsyncFlowControl (t, AsyncFlowControlType.Execution);
 252                 }
 253
 254                 internal static LogicalCallContext CreateLogicalCallContext (bool createEmpty)
 255                 {
 256                         var lcc = Current._lcc;
 257                         if (lcc == null) {
 258                                 if (createEmpty)
 259                                         lcc = new LogicalCallContext ();
 260
 261                                 return lcc;
 262                         }
 263
 264                         return (LogicalCallContext) lcc.Clone ();
 265                 }
 266
 267                 internal void FreeNamedDataSlot (string name)
 268                 {
 269                         if (_lcc != null)
 270                                 _lcc.FreeNamedDataSlot (name);
 271
 272                         if (local_data != null)
 273                                 local_data.Remove (name);
 274                 }
 275
 276                 internal static ExecutionContext Current {
 277                         get {
 278                                 return Thread.CurrentThread.ExecutionContext;
 279                         }
 280                 }
 281
 282                 internal static ExecutionContext GetCurrentWritable ()
 283                 {
 284                         var current = Thread.CurrentThread.ExecutionContext;
 285                         if (current.CopyOnWrite) {
 286                                 current.CopyOnWrite = false;
 287                                 current.CloneData (current);
 288                         }
 289
 290                         return current;
 291                 }
 292         }
 293 }