mcs/class/corlib/System/Delegate.cs

   1 //
   2 // System.Delegate.cs
   3 //
   4 // Authors:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Daniel Stodden (stodden@in.tum.de)
   7 //   Dietmar Maurer (dietmar@ximian.com)
   8 //
   9 // (C) Ximian, Inc.  http://www.ximian.com
  10 //
  11
  12 //
  13 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using System.Reflection;
  36 using System.Runtime.Remoting;
  37 using System.Runtime.Serialization;
  38 using System.Runtime.CompilerServices;
  39 using System.Runtime.InteropServices;
  40
  41 namespace System
  42 {
  43         /* Contains the rarely used fields of Delegate */
  44         class DelegateData {
  45                 public Type target_type;
  46                 public string method_name;
  47         }
  48
  49         [ClassInterface (ClassInterfaceType.AutoDual)]
  50         [System.Runtime.InteropServices.ComVisible (true)]
  51         [Serializable]
  52         public abstract class Delegate : ICloneable, ISerializable
  53         {
  54                 #region Sync with object-internals.h
  55 #pragma warning disable 169, 414, 649
  56                 private IntPtr method_ptr;
  57                 private IntPtr invoke_impl;
  58                 private object m_target;
  59                 private IntPtr method;
  60                 private IntPtr delegate_trampoline;
  61                 private IntPtr method_code;
  62                 private MethodInfo method_info;
  63
  64                 // Keep a ref of the MethodInfo passed to CreateDelegate.
  65                 // Used to keep DynamicMethods alive.
  66                 private MethodInfo original_method_info;
  67
  68                 private DelegateData data;
  69 #pragma warning restore 169, 414, 649
  70                 #endregion
  71
  72                 protected Delegate (object target, string method)
  73                 {
  74                         if (target == null)
  75                                 throw new ArgumentNullException ("target");
  76
  77                         if (method == null)
  78                                 throw new ArgumentNullException ("method");
  79
  80                         this.m_target = target;
  81                         this.data = new DelegateData ();
  82                         this.data.method_name = method;
  83                 }
  84
  85                 protected Delegate (Type target, string method)
  86                 {
  87                         if (target == null)
  88                                 throw new ArgumentNullException ("target");
  89
  90                         if (method == null)
  91                                 throw new ArgumentNullException ("method");
  92
  93                         this.data = new DelegateData ();
  94                         this.data.method_name = method;
  95                         this.data.target_type = target;
  96                 }
  97
  98                 public MethodInfo Method {
  99                         get {
 100                                 if (method_info != null) {
 101                                         return method_info;
 102                                 } else {
 103                                         if (method != IntPtr.Zero) {
 104                                                 method_info = (MethodInfo)MethodBase.GetMethodFromHandleNoGenericCheck (new RuntimeMethodHandle (method));
 105                                         }
 106                                         return method_info;
 107                                 }
 108                         }
 109                 }
 110
 111                 public object Target {
 112                         get {
 113                                 return m_target;
 114                         }
 115                 }
 116
 117                 //
 118                 // Methods
 119                 //
 120
 121                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 122                 internal static extern Delegate CreateDelegate_internal (Type type, object target, MethodInfo info, bool throwOnBindFailure);
 123
 124                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 125                 internal extern void SetMulticastInvoke ();
 126
 127                 private static bool arg_type_match (Type delArgType, Type argType) {
 128                         bool match = delArgType == argType;
 129
 130                         // Delegate contravariance
 131                         if (!match) {
 132                                 if (!argType.IsValueType && argType.IsAssignableFrom (delArgType))
 133                                         match = true;
 134                         }
 135
 136                         return match;
 137                 }
 138
 139                 private static bool return_type_match (Type delReturnType, Type returnType) {
 140                         bool returnMatch = returnType == delReturnType;
 141
 142                         if (!returnMatch) {
 143                                 // Delegate covariance
 144                                 if (!returnType.IsValueType && delReturnType.IsAssignableFrom (returnType))
 145                                         returnMatch = true;
 146                         }
 147
 148                         return returnMatch;
 149                 }
 150
 151                 public static Delegate CreateDelegate (Type type, object firstArgument, MethodInfo method, bool throwOnBindFailure)
 152                 {
 153                         // The name of the parameter changed in 2.0
 154                         object target = firstArgument;
 155
 156                         if (type == null)
 157                                 throw new ArgumentNullException ("type");
 158
 159                         if (method == null)
 160                                 throw new ArgumentNullException ("method");
 161
 162                         if (!type.IsSubclassOf (typeof (MulticastDelegate)))
 163                                 throw new ArgumentException ("type is not a subclass of Multicastdelegate");
 164
 165                         MethodInfo invoke = type.GetMethod ("Invoke");
 166
 167                         if (!return_type_match (invoke.ReturnType, method.ReturnType))
 168                                 if (throwOnBindFailure)
 169                                         throw new ArgumentException ("method return type is incompatible");
 170                                 else
 171                                         return null;
 172
 173                         ParameterInfo[] delargs = invoke.GetParameters ();
 174                         ParameterInfo[] args = method.GetParameters ();
 175
 176                         bool argLengthMatch;
 177
 178                         if (target != null) {
 179                                 // delegate closed over target
 180                                 if (!method.IsStatic)
 181                                         // target is passed as this
 182                                         argLengthMatch = (args.Length == delargs.Length);
 183                                 else
 184                                         // target is passed as the first argument to the static method
 185                                         argLengthMatch = (args.Length == delargs.Length + 1);
 186                         } else {
 187                                 if (!method.IsStatic)
 188                                         //
 189                                         // Net 2.0 feature. The first argument of the delegate is passed
 190                                         // as the 'this' argument to the method.
 191                                         //
 192                                         argLengthMatch = (args.Length + 1 == delargs.Length);
 193                                 else {
 194                                         argLengthMatch = (args.Length == delargs.Length);
 195
 196                                         if (!argLengthMatch)
 197                                                 // closed over a null reference
 198                                                 argLengthMatch = args.Length == delargs.Length + 1;
 199                                 }
 200                         }
 201                         if (!argLengthMatch)
 202                                 if (throwOnBindFailure)
 203                                         throw new ArgumentException ("method argument length mismatch");
 204                                 else
 205                                         return null;
 206
 207                         bool argsMatch;
 208                         if (target != null) {
 209                                 if (!method.IsStatic) {
 210                                         argsMatch = arg_type_match (target.GetType (), method.DeclaringType);
 211                                         for (int i = 0; i < args.Length; i++)
 212                                                 argsMatch &= arg_type_match (delargs [i].ParameterType, args [i].ParameterType);
 213                                 } else {
 214                                         argsMatch = arg_type_match (target.GetType (), args [0].ParameterType);
 215                                         for (int i = 1; i < args.Length; i++)
 216                                                 argsMatch &= arg_type_match (delargs [i - 1].ParameterType, args [i].ParameterType);
 217                                 }
 218                         } else {
 219                                 if (!method.IsStatic) {
 220                                         // The first argument should match this
 221                                         argsMatch = arg_type_match (delargs [0].ParameterType, method.DeclaringType);
 222                                         for (int i = 0; i < args.Length; i++)
 223                                                 argsMatch &= arg_type_match (delargs [i + 1].ParameterType, args [i].ParameterType);
 224                                 } else {
 225                                         if (delargs.Length + 1 == args.Length) {
 226                                                 // closed over a null reference
 227                                                 argsMatch = !args [0].ParameterType.IsValueType;
 228                                                 for (int i = 0; i < delargs.Length; i++)
 229                                                         argsMatch &= arg_type_match (delargs [i].ParameterType, args [i + 1].ParameterType);
 230                                         } else {
 231                                                 argsMatch = true;
 232                                                 for (int i = 0; i < args.Length; i++)
 233                                                         argsMatch &= arg_type_match (delargs [i].ParameterType, args [i].ParameterType);
 234                                         }
 235                                 }
 236                         }
 237
 238                         if (!argsMatch)
 239                                 if (throwOnBindFailure)
 240                                         throw new ArgumentException ("method arguments are incompatible");
 241                                 else
 242                                         return null;
 243
 244                         Delegate d = CreateDelegate_internal (type, target, method, throwOnBindFailure);
 245                         if (d != null)
 246                                 d.original_method_info = method;
 247                         return d;
 248                 }
 249
 250                 public static Delegate CreateDelegate (Type type, object firstArgument, MethodInfo method) {
 251                         return CreateDelegate (type, firstArgument, method, true);
 252                 }
 253
 254                 public static Delegate CreateDelegate (Type type, MethodInfo method, bool throwOnBindFailure)
 255                 {
 256                         return CreateDelegate (type, null, method, throwOnBindFailure);
 257                 }
 258
 259                 public static Delegate CreateDelegate (Type type, MethodInfo method) {
 260                         return CreateDelegate (type, method, true);
 261                 }
 262
 263                 public static Delegate CreateDelegate (Type type, object target, string method)
 264                 {
 265                         return CreateDelegate(type, target, method, false);
 266                 }
 267
 268                 static MethodInfo GetCandidateMethod (Type type, Type target, string method, BindingFlags bflags, bool ignoreCase, bool throwOnBindFailure)
 269                 {
 270                         if (type == null)
 271                                 throw new ArgumentNullException ("type");
 272
 273                         if (method == null)
 274                                 throw new ArgumentNullException ("method");
 275
 276                         if (!type.IsSubclassOf (typeof (MulticastDelegate)))
 277                                 throw new ArgumentException ("type is not subclass of MulticastDelegate.");
 278
 279                         MethodInfo invoke = type.GetMethod ("Invoke");
 280                         ParameterInfo [] delargs = invoke.GetParameters ();
 281                         Type[] delargtypes = new Type [delargs.Length];
 282
 283                         for (int i=0; i<delargs.Length; i++)
 284                                 delargtypes [i] = delargs [i].ParameterType;
 285
 286                         /*
 287                          * FIXME: we should check the caller has reflection permission
 288                          * or if it lives in the same assembly...
 289                          */
 290
 291                         /*
 292                          * since we need to walk the inheritance chain anyway to
 293                          * find private methods, adjust the bindingflags to ignore
 294                          * inherited methods
 295                          */
 296                         BindingFlags flags = BindingFlags.ExactBinding |
 297                                 BindingFlags.Public | BindingFlags.NonPublic |
 298                                 BindingFlags.DeclaredOnly | bflags;
 299
 300                         if (ignoreCase)
 301                                 flags |= BindingFlags.IgnoreCase;
 302
 303                         MethodInfo info = null;
 304
 305                         for (Type targetType = target; targetType != null; targetType = targetType.BaseType) {
 306                                 MethodInfo mi = targetType.GetMethod (method, flags,
 307                                         null, delargtypes, new ParameterModifier [0]);
 308                                 if (mi != null && return_type_match (invoke.ReturnType, mi.ReturnType)) {
 309                                         info = mi;
 310                                         break;
 311                                 }
 312                         }
 313
 314                         if (info == null) {
 315                                 if (throwOnBindFailure)
 316                                         throw new ArgumentException ("Couldn't bind to method '" + method + "'.");
 317                                 else
 318                                         return null;
 319                         }
 320
 321                         return info;
 322                 }
 323
 324                 public static Delegate CreateDelegate (Type type, Type target, string method, bool ignoreCase, bool throwOnBindFailure)
 325                 {
 326                         if (target == null)
 327                                 throw new ArgumentNullException ("target");
 328
 329                         MethodInfo info = GetCandidateMethod (type, target, method,
 330                                 BindingFlags.Static, ignoreCase, throwOnBindFailure);
 331                         if (info == null)
 332                                 return null;
 333
 334                         return CreateDelegate_internal (type, null, info, throwOnBindFailure);
 335                 }
 336
 337                 public static Delegate CreateDelegate (Type type, Type target, string method) {
 338                         return CreateDelegate (type, target, method, false, true);
 339                 }
 340
 341                 public static Delegate CreateDelegate (Type type, Type target, string method, bool ignoreCase) {
 342                         return CreateDelegate (type, target, method, ignoreCase, true);
 343                 }
 344
 345                 public static Delegate CreateDelegate (Type type, object target, string method, bool ignoreCase, bool throwOnBindFailure)
 346                 {
 347                         if (target == null)
 348                                 throw new ArgumentNullException ("target");
 349
 350                         MethodInfo info = GetCandidateMethod (type, target.GetType (), method,
 351                                 BindingFlags.Instance, ignoreCase, throwOnBindFailure);
 352                         if (info == null)
 353                                 return null;
 354
 355                         return CreateDelegate_internal (type, target, info, throwOnBindFailure);
 356                 }
 357
 358                 public static Delegate CreateDelegate (Type type, object target, string method, bool ignoreCase) {
 359                         return CreateDelegate (type, target, method, ignoreCase, true);
 360                 }
 361
 362                 public object DynamicInvoke (params object[] args)
 363                 {
 364                         return DynamicInvokeImpl (args);
 365                 }
 366
 367                 protected virtual object DynamicInvokeImpl (object[] args)
 368                 {
 369                         if (Method == null) {
 370                                 Type[] mtypes = new Type [args.Length];
 371                                 for (int i = 0; i < args.Length; ++i) {
 372                                         mtypes [i] = args [i].GetType ();
 373                                 }
 374                                 method_info = m_target.GetType ().GetMethod (data.method_name, mtypes);
 375                         }
 376
 377                         if ((m_target != null) && Method.IsStatic) {
 378                                 // The delegate is bound to m_target
 379                                 if (args != null) {
 380                                         object[] newArgs = new object [args.Length + 1];
 381                                         args.CopyTo (newArgs, 1);
 382                                         newArgs [0] = m_target;
 383                                         args = newArgs;
 384                                 } else {
 385                                         args = new object [] { m_target };
 386                                 }
 387                                 return Method.Invoke (null, args);
 388                         }
 389
 390                         return Method.Invoke (m_target, args);
 391                 }
 392
 393                 public virtual object Clone ()
 394                 {
 395                         return MemberwiseClone ();
 396                 }
 397
 398                 public override bool Equals (object obj)
 399                 {
 400                         Delegate d = obj as Delegate;
 401
 402                         if (d == null)
 403                                 return false;
 404
 405                         // Do not compare method_ptr, since it can point to a trampoline
 406                         if (d.m_target == m_target && d.method == method) {
 407                                 if (d.data != null || data != null) {
 408                                         /* Uncommon case */
 409                                         if (d.data != null && data != null)
 410                                                 return (d.data.target_type == data.target_type && d.data.method_name == data.method_name);
 411                                         else
 412                                                 return false;
 413                                 }
 414                                 return true;
 415                         }
 416
 417                         return false;
 418                 }
 419
 420                 public override int GetHashCode ()
 421                 {
 422                         return method.GetHashCode () ^ (m_target != null ? m_target.GetHashCode () : 0);
 423                 }
 424
 425                 protected virtual MethodInfo GetMethodImpl ()
 426                 {
 427                         return Method;
 428                 }
 429
 430                 // This is from ISerializable
 431                 public virtual void GetObjectData (SerializationInfo info, StreamingContext context)
 432                 {
 433                         DelegateSerializationHolder.GetDelegateData (this, info, context);
 434                 }
 435
 436                 public virtual Delegate[] GetInvocationList()
 437                 {
 438                         return new Delegate[] { this };
 439                 }
 440
 441                 /// <symmary>
 442                 ///   Returns a new MulticastDelegate holding the
 443                 ///   concatenated invocation lists of MulticastDelegates a and b
 444                 /// </symmary>
 445                 public static Delegate Combine (Delegate a, Delegate b)
 446                 {
 447                         if (a == null) {
 448                                 if (b == null)
 449                                         return null;
 450                                 return b;
 451                         } else
 452                                 if (b == null)
 453                                         return a;
 454
 455                         if (a.GetType () != b.GetType ())
 456                                 throw new ArgumentException (Locale.GetText ("Incompatible Delegate Types."));
 457
 458                         return a.CombineImpl (b);
 459                 }
 460
 461                 /// <symmary>
 462                 ///   Returns a new MulticastDelegate holding the
 463                 ///   concatenated invocation lists of an Array of MulticastDelegates
 464                 /// </symmary>
 465                 [System.Runtime.InteropServices.ComVisible (true)]
 466                 public static Delegate Combine (params Delegate[] delegates)
 467                 {
 468                         if (delegates == null)
 469                                 return null;
 470
 471                         Delegate retval = null;
 472
 473                         foreach (Delegate next in delegates)
 474                                 retval = Combine (retval, next);
 475
 476                         return retval;
 477                 }
 478
 479                 protected virtual Delegate CombineImpl (Delegate d)
 480                 {
 481                         throw new MulticastNotSupportedException (String.Empty);
 482                 }
 483
 484                 public static Delegate Remove (Delegate source, Delegate value)
 485                 {
 486                         if (source == null)
 487                                 return null;
 488
 489                         return source.RemoveImpl (value);
 490                 }
 491
 492                 protected virtual Delegate RemoveImpl (Delegate d)
 493                 {
 494                         if (this.Equals (d))
 495                                 return null;
 496
 497                         return this;
 498                 }
 499
 500                 public static Delegate RemoveAll (Delegate source, Delegate value)
 501                 {
 502                         Delegate tmp = source;
 503                         while ((source = Delegate.Remove (source, value)) != tmp)
 504                                 tmp = source;
 505
 506                         return tmp;
 507                 }
 508
 509                 public static bool operator == (Delegate d1, Delegate d2)
 510                 {
 511                         if ((object)d1 == null) {
 512                                 if ((object)d2 == null)
 513                                         return true;
 514                                 return false;
 515                         } else if ((object) d2 == null)
 516                                 return false;
 517
 518                         return d1.Equals (d2);
 519                 }
 520
 521                 public static bool operator != (Delegate d1, Delegate d2)
 522                 {
 523                         return !(d1 == d2);
 524                 }
 525
 526                 internal bool IsTransparentProxy ()
 527                 {
 528                         return RemotingServices.IsTransparentProxy (m_target);
 529                 }
 530         }
 531 }