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;
  38 using System.Collections.Generic;
  39
  40 namespace System.Threading {
  41         [Serializable]
  42         public sealed partial class ExecutionContext : ISerializable
  43            , IDisposable
  44         {
  45                 internal struct Switcher
  46                 {
  47                         readonly ExecutionContext ec;
  48                         readonly LogicalCallContext _lcc;
  49                         readonly bool _suppressFlow;
  50                         readonly bool _capture;
  51                         readonly Dictionary<string, object> local_data;
  52                         readonly bool copy_on_write;
  53
  54                         public Switcher (ExecutionContext ec)
  55                         {
  56                                 this.ec = ec;
  57                                 this._lcc = ec._lcc;
  58                                 this._suppressFlow = ec._suppressFlow;
  59                                 this._capture = ec._capture;
  60                                 this.local_data = ec.local_data;
  61                                 this.copy_on_write = ec.CopyOnWrite;
  62                         }
  63
  64                         public bool IsEmpty {
  65                                 get {
  66                                         return ec == null;
  67                                 }
  68                         }
  69
  70                         public void Restore (ExecutionContext ec)
  71                         {
  72                                 ec._lcc = this._lcc;
  73                                 ec._suppressFlow = this._suppressFlow;
  74                                 ec._capture = this._capture;
  75                                 ec.local_data = this.local_data;
  76                                 ec.CopyOnWrite = this.copy_on_write;
  77                         }
  78                 }
  79
  80 #if !MOBILE
  81                 private SecurityContext _sc;
  82 #endif
  83                 private LogicalCallContext _lcc;
  84                 private bool _suppressFlow;
  85                 private bool _capture;
  86                 Dictionary<string, object> local_data;
  87
  88                 internal ExecutionContext ()
  89                 {
  90                 }
  91
  92                 private ExecutionContext (ExecutionContext ec)
  93                 {
  94                         CloneData (ec);
  95
  96                         _suppressFlow = ec._suppressFlow;
  97                         _capture = true;
  98                 }
  99
 100                 void CloneData (ExecutionContext ec)
 101                 {
 102 #if !MOBILE
 103                         if (ec._sc != null)
 104                                 _sc = new SecurityContext (ec._sc);
 105 #endif
 106                         if (ec._lcc != null)
 107                                 _lcc = (LogicalCallContext) ec._lcc.Clone ();
 108                 }
 109
 110                 [MonoTODO]
 111                 internal ExecutionContext (SerializationInfo info, StreamingContext context)
 112                 {
 113                         throw new NotImplementedException ();
 114                 }
 115
 116                 public static ExecutionContext Capture ()
 117                 {
 118                         return Capture (true, false);
 119                 }
 120
 121                 internal static ExecutionContext Capture (bool captureSyncContext, bool nullOnEmpty)
 122                 {
 123                         var thread = Thread.CurrentThread;
 124                         if (nullOnEmpty && !thread.HasExecutionContext)
 125                                 return null;
 126
 127                         var ec = thread.ExecutionContext;
 128                         if (ec.FlowSuppressed)
 129                                 return null;
 130
 131                         if (nullOnEmpty
 132 #if !MOBILE
 133                          && ec._sc == null
 134 #endif
 135                                 && (ec._lcc == null || !ec._lcc.HasInfo))
 136                                 return null;
 137
 138                         ExecutionContext capture = new ExecutionContext (ec);
 139 #if !MOBILE
 140                         if (SecurityManager.SecurityEnabled)
 141                                 capture.SecurityContext = SecurityContext.Capture ();
 142 #endif
 143                         return capture;
 144                 }
 145
 146                 public ExecutionContext CreateCopy ()
 147                 {
 148                         if (!_capture)
 149                                 throw new InvalidOperationException ();
 150
 151                         return new ExecutionContext (this);
 152                 }
 153
 154                 public void Dispose ()
 155                 {
 156 #if !MOBILE
 157                         if (_sc != null)
 158                                 _sc.Dispose ();
 159 #endif
 160                 }
 161
 162                 [MonoTODO]
 163                 [ReflectionPermission (SecurityAction.Demand, MemberAccess = true)]
 164                 public void GetObjectData (SerializationInfo info, StreamingContext context)
 165                 {
 166                         if (info == null)
 167                                 throw new ArgumentNullException ("info");
 168                         throw new NotImplementedException ();
 169                 }
 170
 171                 // internal stuff
 172
 173                 internal LogicalCallContext LogicalCallContext {
 174                         get {
 175                                 if (_lcc == null)
 176                                         _lcc = new LogicalCallContext ();
 177                                 return _lcc;
 178                         }
 179                         set {
 180                                 _lcc = value;
 181                         }
 182                 }
 183
 184                 internal Dictionary<string, object> DataStore {
 185                         get {
 186                                 if (local_data == null)
 187                                         local_data = new Dictionary<string, object> ();
 188                                 return local_data;
 189                         }
 190                         set {
 191                                 local_data = value;
 192                         }
 193                 }
 194
 195 #if !MOBILE
 196                 internal SecurityContext SecurityContext {
 197                         get {
 198                                 if (_sc == null)
 199                                         _sc = new SecurityContext ();
 200                                 return _sc;
 201                         }
 202                         set { _sc = value; }
 203                 }
 204 #endif
 205
 206                 internal bool FlowSuppressed {
 207                         get { return _suppressFlow; }
 208                         set { _suppressFlow = value; }
 209                 }
 210
 211                 internal bool CopyOnWrite { get; set; }
 212
 213                 public static bool IsFlowSuppressed ()
 214                 {
 215                         return Current.FlowSuppressed;
 216                 }
 217
 218                 public static void RestoreFlow ()
 219                 {
 220                         ExecutionContext ec = Current;
 221                         if (!ec.FlowSuppressed)
 222                                 throw new InvalidOperationException ();
 223
 224                         ec.FlowSuppressed = false;
 225                 }
 226
 227                 internal static void Run(ExecutionContext executionContext, ContextCallback callback, Object state, bool preserveSyncCtx)
 228                 {
 229                         Run (executionContext, callback, state);
 230                 }
 231
 232                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 233                 public static void Run (ExecutionContext executionContext, ContextCallback callback, object state)
 234                 {
 235                         if (executionContext == null) {
 236                                 throw new InvalidOperationException (Locale.GetText (
 237                                         "Null ExecutionContext"));
 238                         }
 239
 240                         var prev = Current;
 241                         try {
 242                                 Thread.CurrentThread.ExecutionContext = executionContext;
 243                                 callback (state);
 244                         } finally {
 245                                 Thread.CurrentThread.ExecutionContext = prev;
 246                         }
 247                 }
 248
 249                 public static AsyncFlowControl SuppressFlow ()
 250                 {
 251                         Thread t = Thread.CurrentThread;
 252                         t.ExecutionContext.FlowSuppressed = true;
 253                         return new AsyncFlowControl (t, AsyncFlowControlType.Execution);
 254                 }
 255
 256                 internal static LogicalCallContext CreateLogicalCallContext (bool createEmpty)
 257                 {
 258                         var lcc = Current._lcc;
 259                         LogicalCallContext ctx = null;
 260
 261                         if (lcc != null && lcc.HasInfo) {
 262                                 ctx = new LogicalCallContext ();
 263                                 foreach (DictionaryEntry entry in lcc.Datastore) {
 264                                         ctx.SetData ((string)entry.Key, entry.Value);
 265                                 }
 266                         } else if (createEmpty)
 267                                 ctx = new LogicalCallContext ();
 268
 269                         return ctx;
 270                 }
 271
 272                 internal void FreeNamedDataSlot (string name)
 273                 {
 274                         if (_lcc != null)
 275                                 _lcc.FreeNamedDataSlot (name);
 276
 277                         if (local_data != null)
 278                                 local_data.Remove (name);
 279                 }
 280
 281                 internal static ExecutionContext Current {
 282                         get {
 283                                 return Thread.CurrentThread.ExecutionContext;
 284                         }
 285                 }
 286
 287                 internal static ExecutionContext GetCurrentWritable ()
 288                 {
 289                         var current = Thread.CurrentThread.ExecutionContext;
 290                         if (current.CopyOnWrite) {
 291                                 current.CopyOnWrite = false;
 292                                 current.CloneData (current);
 293                         }
 294
 295                         return current;
 296                 }
 297         }
 298 }