mcs/mcs/delegate.cs

   1 //\r
   2 // delegate.cs: Delegate Handler\r
   3 //\r
   4 // Author: Ravi Pratap (ravi@ximian.com)\r
   5 //\r
   6 // Licensed under the terms of the GNU GPL\r
   7 //\r
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)\r
   9 //\r
  10 //\r
  11 \r
  12 using System;\r
  13 using System.Collections;\r
  14 using System.Reflection;\r
  15 using System.Reflection.Emit;\r
  16 using System.Text;\r
  17 \r
  18 namespace Mono.CSharp {\r
  19 \r
  20         /// <summary>\r
  21         ///   Holds Delegates\r
  22         /// </summary>\r
  23         public class Delegate : MemberCore {\r
  24                 public readonly string ReturnType;\r
  25                 public Parameters      Parameters;\r
  26                 public Attributes      OptAttributes;\r
  27                 public TypeBuilder     TypeBuilder;\r
  28 \r
  29                 public ConstructorBuilder ConstructorBuilder;\r
  30                 public MethodBuilder      InvokeBuilder;\r
  31                 public MethodBuilder      BeginInvokeBuilder;\r
  32                 public MethodBuilder      EndInvokeBuilder;\r
  33                 \r
  34                 Type [] param_types;\r
  35                 Type ret_type;\r
  36                 \r
  37                 Expression instance_expr;\r
  38                 MethodBase delegate_method;\r
  39         \r
  40                 const int AllowedModifiers =\r
  41                         Modifiers.NEW |\r
  42                         Modifiers.PUBLIC |\r
  43                         Modifiers.PROTECTED |\r
  44                         Modifiers.INTERNAL |\r
  45                         Modifiers.PRIVATE;\r
  46 \r
  47                 public Delegate (string type, int mod_flags, string name, Parameters param_list,\r
  48                                  Attributes attrs, Location l)\r
  49                         : base (name, l)\r
  50                 {\r
  51                         this.ReturnType = type;\r
  52                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags, Modifiers.PUBLIC);\r
  53                         Parameters      = param_list;\r
  54                         OptAttributes   = attrs;\r
  55                 }\r
  56 \r
  57                 public void DefineDelegate (object parent_builder)\r
  58                 {\r
  59                         TypeAttributes attr;\r
  60                         string name = Name.Substring (1 + Name.LastIndexOf ('.'));\r
  61                         \r
  62                         if (parent_builder is ModuleBuilder) {\r
  63                                 ModuleBuilder builder = (ModuleBuilder) parent_builder;\r
  64                                 attr = TypeAttributes.Public | TypeAttributes.Class | TypeAttributes.Sealed;\r
  65 \r
  66                                 TypeBuilder = builder.DefineType (\r
  67                                         name, attr, TypeManager.multicast_delegate_type);\r
  68                         } else {\r
  69                                 // FIXME: We could just use TypeBuilder here.\r
  70                                 TypeBuilder builder = (System.Reflection.Emit.TypeBuilder) parent_builder;\r
  71                                 attr = TypeAttributes.NestedPublic | TypeAttributes.Class |\r
  72                                         TypeAttributes.Sealed;\r
  73 \r
  74                                 TypeBuilder = builder.DefineNestedType (\r
  75                                         name, attr, TypeManager.multicast_delegate_type);\r
  76                         }\r
  77 \r
  78                         RootContext.TypeManager.AddDelegateType (Name, TypeBuilder, this);\r
  79                 }\r
  80 \r
  81                 public override bool Define (TypeContainer parent)\r
  82                 {\r
  83                         MethodAttributes mattr;\r
  84                         int i;\r
  85                         \r
  86                         // FIXME: POSSIBLY make this static, as it is always constant\r
  87                         // \r
  88                         Type [] const_arg_types = new Type [2];\r
  89                         const_arg_types [0] = TypeManager.object_type;\r
  90                         const_arg_types [1] = TypeManager.intptr_type;\r
  91 \r
  92                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |\r
  93                                 MethodAttributes.HideBySig | MethodAttributes.Public;\r
  94 \r
  95                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,\r
  96                                                                             CallingConventions.Standard,\r
  97                                                                             const_arg_types);\r
  98 \r
  99                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");\r
 100                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");\r
 101                         //\r
 102                         // HACK because System.Reflection.Emit is lame\r
 103                         //\r
 104                         //\r
 105                         // FIXME: POSSIBLY make these static, as they are always the same\r
 106                         Parameter [] fixed_pars = new Parameter [2];\r
 107                         fixed_pars [0] = new Parameter (null, null, Parameter.Modifier.NONE, null);\r
 108                         fixed_pars [1] = new Parameter (null, null, Parameter.Modifier.NONE, null);\r
 109                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);\r
 110                         \r
 111                         TypeManager.RegisterMethod (\r
 112                                 ConstructorBuilder,\r
 113                                 new InternalParameters (const_arg_types, const_parameters),\r
 114                                 const_arg_types);\r
 115                                 \r
 116                         \r
 117                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 118                         \r
 119                         // Here the various methods like Invoke, BeginInvoke etc are defined\r
 120 \r
 121                         //\r
 122                         // Invoke method\r
 123                         //\r
 124                         param_types = Parameters.GetParameterInfo (parent);\r
 125                         if (param_types == null)\r
 126                                 return false;\r
 127 \r
 128                         // Check accessibility\r
 129                         foreach (Type partype in param_types)\r
 130                                 if (!TypeContainer.AsAccessible (partype, ModFlags))\r
 131                                         return false;\r
 132                         \r
 133                         ret_type = RootContext.LookupType (parent, ReturnType, false, Location);\r
 134                         if (ret_type == null)\r
 135                                 return false;\r
 136 \r
 137                         if (!TypeContainer.AsAccessible (ret_type, ModFlags))\r
 138                                 return false;\r
 139 \r
 140                         //\r
 141                         // We don't have to check any others because they are all\r
 142                         // guaranteed to be accessible - they are standard types.\r
 143                         //\r
 144                         \r
 145                         CallingConventions cc = Parameters.GetCallingConvention ();\r
 146 \r
 147                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;\r
 148 \r
 149                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke", \r
 150                                                                   mattr,                     \r
 151                                                                   cc,\r
 152                                                                   ret_type,                  \r
 153                                                                   param_types);\r
 154 \r
 155                         for (i = 0 ; i < param_types.Length; i++) {\r
 156                                 Parameter p = Parameters.FixedParameters [i];\r
 157                                 string name = p.Name;\r
 158                                 ParameterBuilder pb = InvokeBuilder.DefineParameter (i+1, p.Attributes, name); \r
 159                         }\r
 160                         \r
 161                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 162 \r
 163                         TypeManager.RegisterMethod (InvokeBuilder,\r
 164                                                     new InternalParameters (parent, Parameters),\r
 165                                                     param_types);\r
 166 \r
 167                         //\r
 168                         // BeginInvoke\r
 169                         //\r
 170                         int params_num = param_types.Length;\r
 171                         Type [] async_param_types = new Type [params_num + 2];\r
 172 \r
 173                         param_types.CopyTo (async_param_types, 0);\r
 174 \r
 175                         async_param_types [params_num] = TypeManager.asynccallback_type;\r
 176                         async_param_types [params_num + 1] = TypeManager.object_type;\r
 177 \r
 178                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual |\r
 179                                 MethodAttributes.NewSlot;\r
 180                         \r
 181                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",\r
 182                                                                        mattr,\r
 183                                                                        cc,\r
 184                                                                        TypeManager.iasyncresult_type,\r
 185                                                                        async_param_types);\r
 186 \r
 187                         for (i = 0 ; i < param_types.Length; i++) {\r
 188                                 Parameter p = Parameters.FixedParameters [i];\r
 189                                 string name = p.Name;\r
 190                                 BeginInvokeBuilder.DefineParameter (i + 1, p.Attributes, name); \r
 191                         }\r
 192                         \r
 193                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");\r
 194                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");\r
 195                         \r
 196                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 197 \r
 198                         Parameter [] async_params = new Parameter [params_num + 2];\r
 199                         if (params_num > 0)\r
 200                                 Parameters.FixedParameters.CopyTo (async_params, 0);\r
 201 \r
 202                         async_params [params_num] = new Parameter ("System.AsyncCallback", "callback",\r
 203                                                                    Parameter.Modifier.NONE, null);\r
 204                         async_params [params_num + 1] = new Parameter ("System.IAsyncResult", "object",\r
 205                                                                    Parameter.Modifier.NONE, null);\r
 206 \r
 207                         TypeManager.RegisterMethod (BeginInvokeBuilder,\r
 208                                                     new InternalParameters (\r
 209                                                             parent,\r
 210                                                             new Parameters (async_params, null, Location)),\r
 211                                                     async_param_types);\r
 212 \r
 213                         //\r
 214                         // EndInvoke\r
 215                         //\r
 216                         Type [] end_param_types = new Type [1];\r
 217                         end_param_types [0] = TypeManager.iasyncresult_type;\r
 218                         \r
 219                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke",\r
 220                                                                      mattr,\r
 221                                                                      cc,\r
 222                                                                      ret_type,\r
 223                                                                      end_param_types);\r
 224                         EndInvokeBuilder.DefineParameter (1, ParameterAttributes.None, "result");\r
 225                         \r
 226                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 227 \r
 228                         Parameter [] end_params = new Parameter [1];\r
 229                         end_params [0] = new Parameter ("System.IAsyncResult", "result",\r
 230                                                         Parameter.Modifier.NONE, null);\r
 231 \r
 232                         TypeManager.RegisterMethod (EndInvokeBuilder,\r
 233                                                     new InternalParameters (\r
 234                                                             parent,\r
 235                                                             new Parameters (end_params, null, Location)),\r
 236                                                     end_param_types);\r
 237 \r
 238                         return true;\r
 239                 }\r
 240 \r
 241                 /// <summary>\r
 242                 ///  Verifies whether the method in question is compatible with the delegate\r
 243                 ///  Returns the method itself if okay and null if not.\r
 244                 /// </summary>\r
 245                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,\r
 246                                                        Location loc)\r
 247                 {\r
 248                         ParameterData pd = Invocation.GetParameterData (mb);\r
 249 \r
 250                         Expression ml = Expression.MemberLookup (\r
 251                                 ec, delegate_type, "Invoke", loc);\r
 252 \r
 253                         if (!(ml is MethodGroupExpr)) {\r
 254                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 255                                 return null;\r
 256                         }\r
 257 \r
 258                         MethodBase invoke_mb = ((MethodGroupExpr) ml).Methods [0];\r
 259 \r
 260                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);\r
 261 \r
 262                         bool mismatch = false;\r
 263                         for (int i = pd.Count; i > 0; ) {\r
 264                                 i--;\r
 265 \r
 266                                 if (invoke_pd.ParameterType (i) == pd.ParameterType (i))\r
 267                                         continue;\r
 268                                 else {\r
 269                                         mismatch = true;\r
 270                                         break;\r
 271                                 }\r
 272                         }\r
 273 \r
 274                         if (mismatch) {\r
 275                                 Report.Error (\r
 276                                         123, loc, "Method '" + Invocation.FullMethodDesc (mb) +\r
 277                                         "' does not match delegate '" +\r
 278                                         FullDelegateDesc (delegate_type, invoke_mb, invoke_pd) + "'");\r
 279                                 return null;\r
 280                         }\r
 281 \r
 282                         if (((MethodInfo) invoke_mb).ReturnType == ((MethodInfo) mb).ReturnType)\r
 283                                 return mb;\r
 284                         else\r
 285                                 mismatch = true;\r
 286 \r
 287                         if (mismatch) {\r
 288                                 Report.Error (123, loc, "Method '" + Invocation.FullMethodDesc (mb) +\r
 289                                               "' does not match delegate '" +\r
 290                                               FullDelegateDesc (delegate_type, invoke_mb, invoke_pd) + "'");\r
 291                                 return null;\r
 292                         }\r
 293 \r
 294                         return null;\r
 295                 }\r
 296 \r
 297                 // <summary>\r
 298                 //  Verifies whether the invocation arguments are compatible with the\r
 299                 //  delegate's target method\r
 300                 // </summary>\r
 301                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type, ArrayList args,\r
 302                                                         Location loc)\r
 303                 {\r
 304                         int arg_count;\r
 305 \r
 306                         if (args == null)\r
 307                                 arg_count = 0;\r
 308                         else\r
 309                                 arg_count = args.Count;\r
 310 \r
 311                         Expression ml = Expression.MemberLookup (\r
 312                                 ec, delegate_type, "Invoke", loc);\r
 313                         \r
 314                         if (!(ml is MethodGroupExpr)) {\r
 315                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 316                                 return false;\r
 317                         }\r
 318                         \r
 319                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];\r
 320 \r
 321                         ParameterData pd = Invocation.GetParameterData (mb);\r
 322                         \r
 323                         if (pd.Count != arg_count) {\r
 324                                 Report.Error (1593, loc,\r
 325                                               "Delegate '" + delegate_type.ToString ()\r
 326                                               + "' does not take '" + arg_count + "' arguments");\r
 327                                 return false;\r
 328                         }\r
 329 \r
 330                         for (int i = arg_count; i > 0;) {\r
 331                                 i--;\r
 332                                 Expression conv;\r
 333                                 Argument a = (Argument) args [i];\r
 334                                 Expression a_expr = a.Expr;\r
 335                                 \r
 336                                 if (pd.ParameterType (i) != a_expr.Type) {\r
 337                                         \r
 338                                         conv = Expression.ConvertImplicitStandard (ec, a_expr, pd.ParameterType (i), loc);\r
 339 \r
 340                                         if (conv == null) {\r
 341                                                 Report.Error (1594, loc,\r
 342                                                               "Delegate '" + delegate_type.ToString () +\r
 343                                                               "' has some invalid arguments.");\r
 344 \r
 345                                                 Report.Error (1503, loc,\r
 346                                                        "Argument " + (i+1) +\r
 347                                                        ": Cannot convert from '" +\r
 348                                                        TypeManager.CSharpName (a_expr.Type)\r
 349                                                        + "' to '" + TypeManager.CSharpName (pd.ParameterType (i)) + "'");\r
 350                                                 return false;\r
 351                                         }\r
 352 \r
 353                                         if (a_expr != conv)\r
 354                                                 a.Expr = conv;\r
 355                                 }\r
 356                         }\r
 357 \r
 358                         return true;\r
 359                 }\r
 360 \r
 361                 /// <summary>\r
 362                 ///  Verifies whether the delegate in question is compatible with this one in\r
 363                 ///  order to determine if instantiation from the same is possible.\r
 364                 /// </summary>\r
 365                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)\r
 366                 {\r
 367                         Expression ml = Expression.MemberLookup (\r
 368                                 ec, delegate_type, "Invoke", loc);\r
 369                         \r
 370                         if (!(ml is MethodGroupExpr)) {\r
 371                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 372                                 return false;\r
 373                         }\r
 374                         \r
 375                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];\r
 376                         ParameterData pd = Invocation.GetParameterData (mb);\r
 377 \r
 378                         Expression probe_ml = Expression.MemberLookup (\r
 379                                 ec, delegate_type, "Invoke", loc);\r
 380                         \r
 381                         if (!(probe_ml is MethodGroupExpr)) {\r
 382                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 383                                 return false;\r
 384                         }\r
 385                         \r
 386                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];\r
 387                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);\r
 388                         \r
 389                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)\r
 390                                 return false;\r
 391 \r
 392                         if (pd.Count != probe_pd.Count)\r
 393                                 return false;\r
 394 \r
 395                         for (int i = pd.Count; i > 0; ) {\r
 396                                 i--;\r
 397 \r
 398                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||\r
 399                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))\r
 400                                         return false;\r
 401                         }\r
 402                         \r
 403                         return true;\r
 404                 }\r
 405                 \r
 406                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)\r
 407                 {\r
 408                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));\r
 409                         \r
 410                         sb.Append (" " + del_type.ToString ());\r
 411                         sb.Append (" (");\r
 412 \r
 413                         int length = pd.Count;\r
 414                         \r
 415                         for (int i = length; i > 0; ) {\r
 416                                 i--;\r
 417                                 \r
 418                                 sb.Append (TypeManager.CSharpName (pd.ParameterType (length - i - 1)));\r
 419                                 if (i != 0)\r
 420                                         sb.Append (", ");\r
 421                         }\r
 422                         \r
 423                         sb.Append (")");\r
 424                         return sb.ToString ();\r
 425                         \r
 426                 }\r
 427                 \r
 428                 // Hack around System.Reflection as found everywhere else\r
 429                 public MemberInfo [] FindMembers (MemberTypes mt, BindingFlags bf, MemberFilter filter, object criteria)\r
 430                 {\r
 431                         ArrayList members = new ArrayList ();\r
 432 \r
 433                         if ((mt & MemberTypes.Method) != 0) {\r
 434                                 if (filter (ConstructorBuilder, criteria))\r
 435                                         members.Add (ConstructorBuilder);\r
 436 \r
 437                                 if (filter (InvokeBuilder, criteria))\r
 438                                         members.Add (InvokeBuilder);\r
 439 \r
 440                                 if (filter (BeginInvokeBuilder, criteria))\r
 441                                         members.Add (BeginInvokeBuilder);\r
 442 \r
 443                                 if (filter (EndInvokeBuilder, criteria))\r
 444                                         members.Add (EndInvokeBuilder);\r
 445                         }\r
 446 \r
 447                         int count = members.Count;\r
 448 \r
 449                         if (count > 0) {\r
 450                                 MemberInfo [] mi = new MemberInfo [count];\r
 451                                 members.CopyTo (mi, 0);\r
 452                                 return mi;\r
 453                         }\r
 454 \r
 455                         return null;\r
 456                 }\r
 457                 \r
 458                 public void CloseDelegate ()\r
 459                 {\r
 460                         TypeBuilder.CreateType ();\r
 461                 }\r
 462                 \r
 463                 public Expression InstanceExpression {\r
 464                         get {\r
 465                                 return instance_expr;\r
 466                         }\r
 467                         set {\r
 468                                 instance_expr = value;\r
 469                         }\r
 470                 }\r
 471 \r
 472                 public MethodBase TargetMethod {\r
 473                         get {\r
 474                                 return delegate_method;\r
 475                         }\r
 476                         set {\r
 477                                 delegate_method = value;\r
 478                         }\r
 479                 }\r
 480 \r
 481                 public Type TargetReturnType {\r
 482                         get {\r
 483                                 return ret_type;\r
 484                         }\r
 485                 }\r
 486 \r
 487                 public Type [] ParameterTypes {\r
 488                         get {\r
 489                                 return param_types;\r
 490                         }\r
 491                 }\r
 492                 \r
 493         }\r
 494 \r
 495         public class NewDelegate : Expression {\r
 496 \r
 497                 public ArrayList Arguments;\r
 498 \r
 499                 MethodBase constructor_method;\r
 500                 MethodBase delegate_method;\r
 501                 Expression delegate_instance_expr;\r
 502 \r
 503                 Location Location;\r
 504                 \r
 505                 public NewDelegate (Type type, ArrayList Arguments, Location loc)\r
 506                 {\r
 507                         this.type = type;\r
 508                         this.Arguments = Arguments;\r
 509                         this.Location  = loc; \r
 510                 }\r
 511 \r
 512                 public override Expression DoResolve (EmitContext ec)\r
 513                 {\r
 514                         if (Arguments == null) {\r
 515                                 Report.Error (-11, Location,\r
 516                                               "Delegate creation expression takes only one argument");\r
 517                                 return null;\r
 518                         }\r
 519                         \r
 520                         if (Arguments.Count != 1) {\r
 521                                 Report.Error (-11, Location,\r
 522                                               "Delegate creation expression takes only one argument");\r
 523                                 return null;\r
 524                         }\r
 525 \r
 526                         Expression ml = Expression.MemberLookup (\r
 527                                 ec, type, ".ctor", Location);\r
 528 \r
 529                         if (!(ml is MethodGroupExpr)) {\r
 530                                 Report.Error (-100, Location, "Internal error : Could not find delegate constructor!");\r
 531                                 return null;\r
 532                         }\r
 533 \r
 534                         constructor_method = ((MethodGroupExpr) ml).Methods [0];\r
 535                         \r
 536                         Argument a = (Argument) Arguments [0];\r
 537                         \r
 538                         if (!a.Resolve (ec, Location))\r
 539                                 return null;\r
 540                         \r
 541                         Expression e = a.Expr;\r
 542 \r
 543                         if (e is MethodGroupExpr) {\r
 544                                 MethodGroupExpr mg = (MethodGroupExpr) e;\r
 545 \r
 546                                 if (mg.Methods.Length > 1) {\r
 547                                         Report.Error (-14, Location, "Ambiguous method reference in delegate creation");\r
 548                                         return null;\r
 549                                 }\r
 550                                 \r
 551                                 delegate_method  = Delegate.VerifyMethod (ec, type, mg.Methods [0], Location);\r
 552                                 \r
 553                                 if (delegate_method == null)\r
 554                                         return null;\r
 555 \r
 556                                 if (mg.InstanceExpression != null)\r
 557                                         delegate_instance_expr = mg.InstanceExpression.Resolve (ec);\r
 558                                 else {\r
 559                                         if (!ec.IsStatic)\r
 560                                                 delegate_instance_expr = ec.This;\r
 561                                         else\r
 562                                                 delegate_instance_expr = null;\r
 563                                 }\r
 564 \r
 565                                 if (delegate_instance_expr != null)\r
 566                                         if (delegate_instance_expr.Type.IsValueType)\r
 567                                                 delegate_instance_expr = new BoxedCast (delegate_instance_expr);\r
 568                                 \r
 569                                 eclass = ExprClass.Value;\r
 570                                 return this;\r
 571                         }\r
 572 \r
 573                         Type e_type = e.Type;\r
 574 \r
 575                         if (!TypeManager.IsDelegateType (e_type)) {\r
 576                                 Report.Error (-12, Location, "Cannot create a delegate from something " +\r
 577                                               "not a delegate or a method.");\r
 578                                 return null;\r
 579                         }\r
 580 \r
 581                         // This is what MS' compiler reports. We could always choose\r
 582                         // to be more verbose and actually give delegate-level specifics\r
 583                         \r
 584                         if (!Delegate.VerifyDelegate (ec, type, e_type, Location)) {\r
 585                                 Report.Error (29, Location, "Cannot implicitly convert type '" + e_type + "' " +\r
 586                                               "to type '" + type + "'");\r
 587                                 return null;\r
 588                         }\r
 589 \r
 590                         Expression invoke_method = Expression.MemberLookup (\r
 591                                 ec, e_type, "Invoke", MemberTypes.Method,\r
 592                                 Expression.AllBindingFlags, Location);\r
 593 \r
 594                         if (invoke_method == null) {\r
 595                                 Report.Error (-200, Location, "Internal error ! COuld not find Invoke method!");\r
 596                                 return null;\r
 597                         }\r
 598                                 \r
 599                         delegate_instance_expr = e;\r
 600                         delegate_method        = ((MethodGroupExpr) invoke_method).Methods [0];\r
 601                         \r
 602                         eclass = ExprClass.Value;\r
 603                         return this;\r
 604                 }\r
 605                 \r
 606                 public override void Emit (EmitContext ec)\r
 607                 {\r
 608                         if (delegate_instance_expr == null)\r
 609                                 ec.ig.Emit (OpCodes.Ldnull);\r
 610                         else\r
 611                                 delegate_instance_expr.Emit (ec);\r
 612                         \r
 613                         ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);\r
 614                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);\r
 615                 }\r
 616         }\r
 617 \r
 618         public class DelegateInvocation : ExpressionStatement {\r
 619 \r
 620                 public Expression InstanceExpr;\r
 621                 public ArrayList  Arguments;\r
 622                 public Location   Location;\r
 623 \r
 624                 MethodBase method;\r
 625                 \r
 626                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)\r
 627                 {\r
 628                         this.InstanceExpr = instance_expr;\r
 629                         this.Arguments = args;\r
 630                         this.Location = loc;\r
 631                 }\r
 632 \r
 633                 public override Expression DoResolve (EmitContext ec)\r
 634                 {\r
 635                         Type del_type = InstanceExpr.Type;\r
 636 \r
 637                         if (del_type == null)\r
 638                                 return null;\r
 639                         \r
 640                         if (Arguments != null){\r
 641                                 for (int i = Arguments.Count; i > 0;){\r
 642                                         --i;\r
 643                                         Argument a = (Argument) Arguments [i];\r
 644                                         \r
 645                                         if (!a.Resolve (ec, Location))\r
 646                                                 return null;\r
 647                                 }\r
 648                         }\r
 649                         \r
 650                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, Location))\r
 651                                 return null;\r
 652 \r
 653                         Expression ml = Expression.MemberLookup (ec, del_type, "Invoke", Location);\r
 654                         \r
 655                         if (!(ml is MethodGroupExpr)) {\r
 656                                 Report.Error (-100, Location, "Internal error : could not find Invoke method!");\r
 657                                 return null;\r
 658                         }\r
 659                         \r
 660                         method = ((MethodGroupExpr) ml).Methods [0];\r
 661                         \r
 662                         type = ((MethodInfo) method).ReturnType;\r
 663                         \r
 664                         eclass = ExprClass.Value;\r
 665                         \r
 666                         return this;\r
 667                 }\r
 668 \r
 669                 public override void Emit (EmitContext ec)\r
 670                 {\r
 671                         Delegate del = TypeManager.LookupDelegate (InstanceExpr.Type);\r
 672 \r
 673                         //\r
 674                         // Invocation on delegates call the virtual Invoke member\r
 675                         // so we are always `instance' calls\r
 676                         //\r
 677                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments);\r
 678                 }\r
 679 \r
 680                 public override void EmitStatement (EmitContext ec)\r
 681                 {\r
 682                         Emit (ec);\r
 683                         // \r
 684                         // Pop the return value if there is one\r
 685                         //\r
 686                         if (method is MethodInfo){\r
 687                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)\r
 688                                         ec.ig.Emit (OpCodes.Pop);\r
 689                         }\r
 690                 }\r
 691 \r
 692         }\r
 693 }\r