mcs/mcs/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Authors:
   5 //     Ravi Pratap (ravi@ximian.com)
   6 //     Miguel de Icaza (miguel@ximian.com)
   7 //     Marek Safar (marek.safar@gmail.com)
   8 //
   9 // Licensed under the terms of the GNU GPL
  10 //
  11 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  12 //
  13 //
  14
  15 using System;
  16 using System.Collections;
  17 using System.Reflection;
  18 using System.Reflection.Emit;
  19 using System.Text;
  20
  21 namespace Mono.CSharp {
  22
  23         /// <summary>
  24         ///   Holds Delegates
  25         /// </summary>
  26         public class Delegate : DeclSpace, IMemberContainer
  27         {
  28                 public Expression ReturnType;
  29                 public Parameters      Parameters;
  30
  31                 public ConstructorBuilder ConstructorBuilder;
  32                 public MethodBuilder      InvokeBuilder;
  33                 public MethodBuilder      BeginInvokeBuilder;
  34                 public MethodBuilder      EndInvokeBuilder;
  35
  36                 Type ret_type;
  37
  38                 static string[] attribute_targets = new string [] { "type", "return" };
  39
  40                 Expression instance_expr;
  41                 MethodBase delegate_method;
  42                 ReturnParameter return_attributes;
  43
  44                 MemberCache member_cache;
  45
  46                 const int AllowedModifiers =
  47                         Modifiers.NEW |
  48                         Modifiers.PUBLIC |
  49                         Modifiers.PROTECTED |
  50                         Modifiers.INTERNAL |
  51                         Modifiers.UNSAFE |
  52                         Modifiers.PRIVATE;
  53
  54                 public Delegate (NamespaceEntry ns, DeclSpace parent, Expression type,
  55                                  int mod_flags, MemberName name, Parameters param_list,
  56                                  Attributes attrs)
  57                         : base (ns, parent, name, attrs)
  58
  59                 {
  60                         this.ReturnType = type;
  61                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  62                                                            IsTopLevel ? Modifiers.INTERNAL :
  63                                                            Modifiers.PRIVATE, name.Location);
  64                         Parameters      = param_list;
  65                 }
  66
  67                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  68                 {
  69                         if (a.Target == AttributeTargets.ReturnValue) {
  70                                 if (return_attributes == null)
  71                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  72
  73                                 return_attributes.ApplyAttributeBuilder (a, cb);
  74                                 return;
  75                         }
  76
  77                         base.ApplyAttributeBuilder (a, cb);
  78                 }
  79
  80                 public override TypeBuilder DefineType ()
  81                 {
  82                         if (TypeBuilder != null)
  83                                 return TypeBuilder;
  84
  85                         if (TypeManager.multicast_delegate_type == null && !RootContext.StdLib) {
  86                                 Namespace system = RootNamespace.Global.GetNamespace ("System", true);
  87                                 TypeExpr expr = system.Lookup (this, "MulticastDelegate", Location) as TypeExpr;
  88                                 TypeManager.multicast_delegate_type = expr.Type;
  89                         }
  90
  91                         if (TypeManager.multicast_delegate_type == null)
  92                                 Report.Error (-100, Location, "Internal error: delegate used before " +
  93                                               "System.MulticastDelegate is resolved.  This can only " +
  94                                               "happen during corlib compilation, when using a delegate " +
  95                                               "in any of the `core' classes.  See bug #72015 for details.");
  96
  97                         if (IsTopLevel) {
  98                                 if (TypeManager.NamespaceClash (Name, Location))
  99                                         return null;
 100
 101                                 ModuleBuilder builder = CodeGen.Module.Builder;
 102
 103                                 TypeBuilder = builder.DefineType (
 104                                         Name, TypeAttr, TypeManager.multicast_delegate_type);
 105                         } else {
 106                                 TypeBuilder builder = Parent.TypeBuilder;
 107
 108                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 109                                 TypeBuilder = builder.DefineNestedType (
 110                                         name, TypeAttr, TypeManager.multicast_delegate_type);
 111                         }
 112
 113                         TypeManager.AddUserType (this);
 114
 115 #if GMCS_SOURCE
 116                         if (IsGeneric) {
 117                                 string[] param_names = new string [TypeParameters.Length];
 118                                 for (int i = 0; i < TypeParameters.Length; i++)
 119                                         param_names [i] = TypeParameters [i].Name;
 120
 121                                 GenericTypeParameterBuilder[] gen_params;
 122                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 123
 124                                 int offset = CountTypeParameters - CurrentTypeParameters.Length;
 125                                 for (int i = offset; i < gen_params.Length; i++)
 126                                         CurrentTypeParameters [i - offset].Define (gen_params [i]);
 127
 128                                 foreach (TypeParameter type_param in CurrentTypeParameters) {
 129                                         if (!type_param.Resolve (this))
 130                                                 return null;
 131                                 }
 132
 133                                 Expression current = new SimpleName (
 134                                         MemberName.Basename, TypeParameters, Location);
 135                                 current = current.ResolveAsTypeTerminal (this, false);
 136                                 if (current == null)
 137                                         return null;
 138
 139                                 CurrentType = current.Type;
 140                         }
 141 #endif
 142
 143                         return TypeBuilder;
 144                 }
 145
 146                 public override bool Define ()
 147                 {
 148 #if GMCS_SOURCE
 149                         if (IsGeneric) {
 150                                 foreach (TypeParameter type_param in TypeParameters) {
 151                                         if (!type_param.Resolve (this))
 152                                                 return false;
 153                                 }
 154
 155                                 foreach (TypeParameter type_param in TypeParameters) {
 156                                         if (!type_param.DefineType (this))
 157                                                 return false;
 158                                 }
 159
 160                                 foreach (TypeParameter type_param in TypeParameters) {
 161                                         if (!type_param.CheckDependencies ())
 162                                                 return false;
 163                                 }
 164                         }
 165 #endif
 166                         member_cache = new MemberCache (TypeManager.multicast_delegate_type, this);
 167
 168                         // FIXME: POSSIBLY make this static, as it is always constant
 169                         //
 170                         Type [] const_arg_types = new Type [2];
 171                         const_arg_types [0] = TypeManager.object_type;
 172                         const_arg_types [1] = TypeManager.intptr_type;
 173
 174                         const MethodAttributes ctor_mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 175                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 176
 177                         ConstructorBuilder = TypeBuilder.DefineConstructor (ctor_mattr,
 178                                                                             CallingConventions.Standard,
 179                                                                             const_arg_types);
 180
 181                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 182                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 183                         //
 184                         // HACK because System.Reflection.Emit is lame
 185                         //
 186                         Parameter [] fixed_pars = new Parameter [2];
 187                         fixed_pars [0] = new Parameter (TypeManager.object_type, "object",
 188                                                         Parameter.Modifier.NONE, null, Location);
 189                         fixed_pars [1] = new Parameter (TypeManager.intptr_type, "method",
 190                                                         Parameter.Modifier.NONE, null, Location);
 191                         Parameters const_parameters = new Parameters (fixed_pars);
 192                         const_parameters.Resolve (null);
 193
 194                         TypeManager.RegisterMethod (ConstructorBuilder, const_parameters);
 195                         member_cache.AddMember (ConstructorBuilder, this);
 196
 197                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 198
 199                         //
 200                         // Here the various methods like Invoke, BeginInvoke etc are defined
 201                         //
 202                         // First, call the `out of band' special method for
 203                         // defining recursively any types we need:
 204
 205                         if (!Parameters.Resolve (this))
 206                                 return false;
 207
 208                         //
 209                         // Invoke method
 210                         //
 211
 212                         // Check accessibility
 213                         foreach (Type partype in Parameters.Types){
 214                                 if (!IsAccessibleAs (partype)) {
 215                                         Report.SymbolRelatedToPreviousError (partype);
 216                                         Report.Error (59, Location,
 217                                                       "Inconsistent accessibility: parameter type `" +
 218                                                       TypeManager.CSharpName (partype) + "' is less " +
 219                                                           "accessible than delegate `" + GetSignatureForError () + "'");
 220                                         return false;
 221                                 }
 222                         }
 223
 224                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 225                         if (ReturnType == null)
 226                                 return false;
 227
 228                         ret_type = ReturnType.Type;
 229
 230                         if (!IsAccessibleAs (ret_type)) {
 231                                 Report.SymbolRelatedToPreviousError (ret_type);
 232                                 Report.Error (58, Location,
 233                                               "Inconsistent accessibility: return type `" +
 234                                               TypeManager.CSharpName (ret_type) + "' is less " +
 235                                               "accessible than delegate `" + GetSignatureForError () + "'");
 236                                 return false;
 237                         }
 238
 239                         if (RootContext.StdLib && (ret_type == TypeManager.arg_iterator_type || ret_type == TypeManager.typed_reference_type)) {
 240                                 Method.Error1599 (Location, ret_type);
 241                                 return false;
 242                         }
 243
 244                         //
 245                         // We don't have to check any others because they are all
 246                         // guaranteed to be accessible - they are standard types.
 247                         //
 248
 249                         CallingConventions cc = Parameters.CallingConvention;
 250
 251                         const MethodAttributes mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual | MethodAttributes.NewSlot;
 252
 253                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 254                                                                   mattr,
 255                                                                   cc,
 256                                                                   ret_type,
 257                                                                   Parameters.Types);
 258
 259                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 260
 261                         TypeManager.RegisterMethod (InvokeBuilder, Parameters);
 262                         member_cache.AddMember (InvokeBuilder, this);
 263
 264                         //
 265                         // BeginInvoke
 266                         //
 267
 268                         Parameters async_parameters = Parameters.MergeGenerated (Parameters,
 269                                 new Parameter (TypeManager.asynccallback_type, "callback", Parameter.Modifier.NONE, null, Location),
 270                                 new Parameter (TypeManager.object_type, "object", Parameter.Modifier.NONE, null, Location));
 271
 272                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 273                                 mattr, cc, TypeManager.iasyncresult_type, async_parameters.Types);
 274
 275                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 276                         TypeManager.RegisterMethod (BeginInvokeBuilder, async_parameters);
 277                         member_cache.AddMember (BeginInvokeBuilder, this);
 278
 279                         //
 280                         // EndInvoke is a bit more interesting, all the parameters labeled as
 281                         // out or ref have to be duplicated here.
 282                         //
 283
 284                         //
 285                         // Define parameters, and count out/ref parameters
 286                         //
 287                         Parameters end_parameters;
 288                         int out_params = 0;
 289
 290                         foreach (Parameter p in Parameters.FixedParameters) {
 291                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 292                                         ++out_params;
 293                         }
 294
 295                         if (out_params > 0) {
 296                                 Type [] end_param_types = new Type [out_params];
 297                                 Parameter [] end_params = new Parameter [out_params ];
 298
 299                                 int param = 0;
 300                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 301                                         Parameter p = Parameters.FixedParameters [i];
 302                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 303                                                 continue;
 304
 305                                         end_param_types [param] = p.ExternalType();
 306                                         end_params [param] = p;
 307                                         ++param;
 308                                 }
 309                                 end_parameters = Parameters.CreateFullyResolved (end_params, end_param_types);
 310                         }
 311                         else {
 312                                 end_parameters = Parameters.EmptyReadOnlyParameters;
 313                         }
 314
 315                         end_parameters = Parameters.MergeGenerated (end_parameters,
 316                                 new Parameter (TypeManager.iasyncresult_type, "result", Parameter.Modifier.NONE, null, Location));
 317
 318                         //
 319                         // Create method, define parameters, register parameters with type system
 320                         //
 321                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_parameters.Types);
 322                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 323
 324                         end_parameters.ApplyAttributes (EndInvokeBuilder);
 325                         TypeManager.RegisterMethod (EndInvokeBuilder, end_parameters);
 326                         member_cache.AddMember (EndInvokeBuilder, this);
 327
 328                         return true;
 329                 }
 330
 331                 public override void Emit ()
 332                 {
 333                         Parameters.ApplyAttributes (InvokeBuilder);
 334
 335                         Parameters p = (Parameters)TypeManager.GetParameterData (BeginInvokeBuilder);
 336                         p.ApplyAttributes (BeginInvokeBuilder);
 337
 338                         if (OptAttributes != null) {
 339                                 OptAttributes.Emit ();
 340                         }
 341
 342                         base.Emit ();
 343                 }
 344
 345                 protected override TypeAttributes TypeAttr {
 346                         get {
 347                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 348                                         TypeAttributes.Class | TypeAttributes.Sealed |
 349                                         base.TypeAttr;
 350                         }
 351                 }
 352
 353                 public override string[] ValidAttributeTargets {
 354                         get {
 355                                 return attribute_targets;
 356                         }
 357                 }
 358
 359                 //TODO: duplicate
 360                 protected override bool VerifyClsCompliance ()
 361                 {
 362                         if (!base.VerifyClsCompliance ()) {
 363                                 return false;
 364                         }
 365
 366                         Parameters.VerifyClsCompliance ();
 367
 368                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 369                                 Report.Error (3002, Location, "Return type of `{0}' is not CLS-compliant", GetSignatureForError ());
 370                         }
 371                         return true;
 372                 }
 373
 374
 375                 public static ConstructorInfo GetConstructor (Type container_type, Type delegate_type)
 376                 {
 377                         Type dt = delegate_type;
 378 #if GMCS_SOURCE
 379                         Type[] g_args = null;
 380                         if (delegate_type.IsGenericType) {
 381                                 g_args = delegate_type.GetGenericArguments ();
 382                                 delegate_type = delegate_type.GetGenericTypeDefinition ();
 383                         }
 384 #endif
 385
 386                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 387                         if (d != null) {
 388 #if GMCS_SOURCE
 389                                 if (g_args != null)
 390                                         return TypeBuilder.GetConstructor (dt, d.ConstructorBuilder);
 391 #endif
 392                                 return d.ConstructorBuilder;
 393                         }
 394
 395                         Expression ml = Expression.MemberLookup (container_type,
 396                                 null, dt, ConstructorInfo.ConstructorName, MemberTypes.Constructor,
 397                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly, Location.Null);
 398
 399                         MethodGroupExpr mg = ml as MethodGroupExpr;
 400                         if (mg == null) {
 401                                 Report.Error (-100, Location.Null, "Internal error: could not find delegate constructor!");
 402                                 // FIXME: null will cause a crash later
 403                                 return null;
 404                         }
 405
 406                         return (ConstructorInfo) mg.Methods[0];
 407                 }
 408
 409                 //
 410                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 411                 // to extract the signature of a delegate.
 412                 //
 413                 public static MethodInfo GetInvokeMethod (Type container_type, Type delegate_type)
 414                 {
 415                         Type dt = delegate_type;
 416 #if GMCS_SOURCE
 417                         Type[] g_args = null;
 418                         if (delegate_type.IsGenericType) {
 419                                 g_args = delegate_type.GetGenericArguments ();
 420                                 delegate_type = delegate_type.GetGenericTypeDefinition ();
 421                         }
 422 #endif
 423                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 424                         if (d != null) {
 425 #if GMCS_SOURCE
 426                                 if (g_args != null) {
 427                                         MethodInfo invoke = TypeBuilder.GetMethod (dt, d.InvokeBuilder);
 428 #if MS_COMPATIBLE
 429                                         Parameters p = (Parameters) d.Parameters.InflateTypes (g_args, g_args);
 430                                         TypeManager.RegisterMethod (invoke, p);
 431 #endif
 432                                         return invoke;
 433                                 }
 434 #endif
 435                                 return d.InvokeBuilder;
 436                         }
 437
 438                         Expression ml = Expression.MemberLookup (container_type, null, dt,
 439                                 "Invoke", Location.Null);
 440
 441                         MethodGroupExpr mg = ml as MethodGroupExpr;
 442                         if (mg == null) {
 443                                 Report.Error (-100, Location.Null, "Internal error: could not find Invoke method!");
 444                                 // FIXME: null will cause a crash later
 445                                 return null;
 446                         }
 447
 448                         return (MethodInfo) mg.Methods[0];
 449                 }
 450
 451                 public static bool IsTypeCovariant (Expression a, Type b)
 452                 {
 453                         Type a_type = a.Type;
 454                         if (a_type == b)
 455                                 return true;
 456
 457                         if (RootContext.Version == LanguageVersion.ISO_1)
 458                                 return false;
 459
 460                         if (a.Type.IsValueType)
 461                                 return false;
 462
 463                         return Convert.ImplicitReferenceConversionCore (
 464                                 a, b);
 465                 }
 466
 467                 /// <summary>
 468                 ///  Verifies whether the method in question is compatible with the delegate
 469                 ///  Returns the method itself if okay and null if not.
 470                 /// </summary>
 471                 public static MethodBase VerifyMethod (Type container_type, Type delegate_type,
 472                                                        MethodGroupExpr old_mg, MethodBase mb,
 473                                                        Location loc)
 474                 {
 475                         MethodInfo invoke_mb = GetInvokeMethod (container_type, delegate_type);
 476                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 477
 478 #if GMCS_SOURCE
 479                         if (old_mg.type_arguments == null &&
 480                             !TypeManager.InferTypeArguments (invoke_pd, ref mb))
 481                                 return null;
 482 #endif
 483
 484                         ParameterData pd = TypeManager.GetParameterData (mb);
 485
 486                         if (invoke_pd.Count != pd.Count)
 487                                 return null;
 488
 489                         for (int i = pd.Count; i > 0; ) {
 490                                 i--;
 491
 492                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 493                                 Type pd_type = pd.ParameterType (i);
 494                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 495                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 496
 497                                 invoke_pd_type_mod &= ~Parameter.Modifier.PARAMS;
 498                                 pd_type_mod &= ~Parameter.Modifier.PARAMS;
 499
 500                                 if (invoke_pd_type_mod != pd_type_mod)
 501                                         return null;
 502
 503                                 if (invoke_pd_type == pd_type)
 504                                         continue;
 505
 506                                 //if (!IsTypeCovariant (invoke_pd_type, pd_type))
 507                                 //      return null;
 508
 509                                 if (RootContext.Version == LanguageVersion.ISO_1)
 510                                         return null;
 511                         }
 512
 513                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 514                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 515                         if (invoke_mb_retval == mb_retval)
 516                                 return mb;
 517
 518                         //if (!IsTypeCovariant (mb_retval, invoke_mb_retval))
 519                         //      return null;
 520
 521                         if (RootContext.Version == LanguageVersion.ISO_1)
 522                                 return null;
 523
 524                         return mb;
 525                 }
 526
 527                 // <summary>
 528                 //  Verifies whether the invocation arguments are compatible with the
 529                 //  delegate's target method
 530                 // </summary>
 531                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 532                                                         ArrayList args, Location loc)
 533                 {
 534                         int arg_count;
 535
 536                         if (args == null)
 537                                 arg_count = 0;
 538                         else
 539                                 arg_count = args.Count;
 540
 541                         Expression ml = Expression.MemberLookup (
 542                                 ec.ContainerType, delegate_type, "Invoke", loc);
 543
 544                         MethodGroupExpr me = ml as MethodGroupExpr;
 545                         if (me == null) {
 546                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 547                                 return false;
 548                         }
 549
 550                         MethodBase mb = GetInvokeMethod (ec.ContainerType, delegate_type);
 551                         ParameterData pd = TypeManager.GetParameterData (mb);
 552
 553                         int pd_count = pd.Count;
 554
 555                         bool params_method = pd.HasParams;
 556                         bool is_params_applicable = false;
 557                         me.DelegateType = delegate_type;
 558                         bool is_applicable = me.IsApplicable (ec, args, arg_count, ref mb, ref is_params_applicable) == 0;
 559
 560                         if (!is_applicable && !params_method && arg_count != pd_count) {
 561                                 Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 562                                         TypeManager.CSharpName (delegate_type), arg_count.ToString ());
 563                                 return false;
 564                         }
 565
 566                         return me.VerifyArgumentsCompat (
 567                                         ec, ref args, arg_count, mb,
 568                                         is_params_applicable || (!is_applicable && params_method),
 569                                         false, loc);
 570                 }
 571
 572                 public static string FullDelegateDesc (MethodBase invoke_method)
 573                 {
 574                         return TypeManager.GetFullNameSignature (invoke_method).Replace (".Invoke", "");
 575                 }
 576
 577                 public override MemberCache MemberCache {
 578                         get {
 579                                 return member_cache;
 580                         }
 581                 }
 582
 583                 public Expression InstanceExpression {
 584                         get {
 585                                 return instance_expr;
 586                         }
 587                         set {
 588                                 instance_expr = value;
 589                         }
 590                 }
 591
 592                 public MethodBase TargetMethod {
 593                         get {
 594                                 return delegate_method;
 595                         }
 596                         set {
 597                                 delegate_method = value;
 598                         }
 599                 }
 600
 601                 public Type TargetReturnType {
 602                         get {
 603                                 return ret_type;
 604                         }
 605                 }
 606
 607                 public override AttributeTargets AttributeTargets {
 608                         get {
 609                                 return AttributeTargets.Delegate;
 610                         }
 611                 }
 612
 613                 //
 614                 //   Represents header string for documentation comment.
 615                 //
 616                 public override string DocCommentHeader {
 617                         get { return "T:"; }
 618                 }
 619
 620                 #region IMemberContainer Members
 621
 622                 string IMemberContainer.Name
 623                 {
 624                         get { throw new NotImplementedException (); }
 625                 }
 626
 627                 Type IMemberContainer.Type
 628                 {
 629                         get { throw new NotImplementedException (); }
 630                 }
 631
 632                 MemberCache IMemberContainer.BaseCache
 633                 {
 634                         get { throw new NotImplementedException (); }
 635                 }
 636
 637                 bool IMemberContainer.IsInterface {
 638                         get {
 639                                 return false;
 640                         }
 641                 }
 642
 643                 MemberList IMemberContainer.GetMembers (MemberTypes mt, BindingFlags bf)
 644                 {
 645                         throw new NotImplementedException ();
 646                 }
 647
 648                 #endregion
 649         }
 650
 651         //
 652         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 653         //
 654         public abstract class DelegateCreation : Expression, MethodGroupExpr.IErrorHandler
 655         {
 656                 protected ConstructorInfo constructor_method;
 657                 protected MethodBase delegate_method;
 658                 // We keep this to handle IsBase only
 659                 protected MethodGroupExpr method_group;
 660                 protected Expression delegate_instance_expression;
 661
 662                 ArrayList CreateDelegateMethodArguments (MethodInfo invoke_method)
 663                 {
 664                         ParameterData pd = TypeManager.GetParameterData (invoke_method);
 665                         ArrayList delegate_arguments = new ArrayList (pd.Count);
 666                         for (int i = 0; i < pd.Count; ++i) {
 667                                 Argument.AType atype_modifier;
 668                                 Type atype = pd.Types [i];
 669                                 switch (pd.ParameterModifier (i)) {
 670                                         case Parameter.Modifier.REF:
 671                                                 atype_modifier = Argument.AType.Ref;
 672                                                 atype = atype.GetElementType ();
 673                                                 break;
 674                                         case Parameter.Modifier.OUT:
 675                                                 atype_modifier = Argument.AType.Out;
 676                                                 atype = atype.GetElementType ();
 677                                                 break;
 678                                         case Parameter.Modifier.ARGLIST:
 679                                                 // __arglist is not valid
 680                                                 throw new InternalErrorException ("__arglist modifier");
 681                                         default:
 682                                                 atype_modifier = Argument.AType.Expression;
 683                                                 break;
 684                                 }
 685                                 delegate_arguments.Add (new Argument (new TypeExpression (atype, loc), atype_modifier));
 686                         }
 687                         return delegate_arguments;
 688                 }
 689
 690                 public override Expression DoResolve (EmitContext ec)
 691                 {
 692                         constructor_method = Delegate.GetConstructor (ec.ContainerType, type);
 693
 694                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.ContainerType, type);
 695                         method_group.DelegateType = type;
 696                         method_group.CustomErrorHandler = this;
 697
 698                         ArrayList arguments = CreateDelegateMethodArguments (invoke_method);
 699                         method_group = method_group.OverloadResolve (ec, ref arguments, false, loc);
 700                         if (method_group == null)
 701                                 return null;
 702
 703                         delegate_method = (MethodInfo) method_group;
 704                         if (method_group is ExtensionMethodGroupExpr) {
 705                                 ParameterData p = TypeManager.GetParameterData (delegate_method);
 706                                 if (p.ExtensionMethodType.IsValueType) {
 707                                         Report.Error (1113, loc, "Extension method `{0}' of value type `{1}' cannot be used to create delegates",
 708                                                 TypeManager.CSharpSignature (delegate_method), TypeManager.CSharpName (p.ExtensionMethodType));
 709                                 }
 710                         }
 711
 712                         Expression ret_expr = new TypeExpression (((MethodInfo) delegate_method).ReturnType, loc);
 713                         if (!Delegate.IsTypeCovariant (ret_expr, (invoke_method.ReturnType))) {
 714                                 Error_ConversionFailed (ec, delegate_method, ret_expr);
 715                         }
 716
 717                         DoResolveInstanceExpression (ec);
 718                         eclass = ExprClass.Value;
 719                         return this;
 720                 }
 721
 722                 void DoResolveInstanceExpression (EmitContext ec)
 723                 {
 724                         //
 725                         // Argument is another delegate
 726                         //
 727                         if (delegate_instance_expression != null)
 728                                 return;
 729
 730                         if (method_group.InstanceExpression != null)
 731                                 delegate_instance_expression = method_group.InstanceExpression;
 732                         else if (!ec.IsStatic)
 733                                 delegate_instance_expression = ec.GetThis (loc);
 734
 735                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 736                                 delegate_instance_expression = new BoxedCast (
 737                                         delegate_instance_expression, TypeManager.object_type);
 738                 }
 739
 740                 public override void Emit (EmitContext ec)
 741                 {
 742                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 743                                 ec.ig.Emit (OpCodes.Ldnull);
 744                         else
 745                                 delegate_instance_expression.Emit (ec);
 746
 747                         if (!delegate_method.DeclaringType.IsSealed && delegate_method.IsVirtual && !method_group.IsBase) {
 748                                 ec.ig.Emit (OpCodes.Dup);
 749                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 750                         } else
 751                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 752                         ec.ig.Emit (OpCodes.Newobj, constructor_method);
 753                 }
 754
 755                 void Error_ConversionFailed (EmitContext ec, MethodBase method, Expression return_type)
 756                 {
 757                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.ContainerType, type);
 758                         string member_name = delegate_instance_expression != null ?
 759                                 Delegate.FullDelegateDesc (method) :
 760                                 TypeManager.GetFullNameSignature (method);
 761
 762                         Report.SymbolRelatedToPreviousError (type);
 763                         Report.SymbolRelatedToPreviousError (method);
 764                         if (RootContext.Version == LanguageVersion.ISO_1) {
 765                                 Report.Error (410, loc, "A method or delegate `{0} {1}' parameters and return type must be same as delegate `{2} {3}' parameters and return type",
 766                                         TypeManager.CSharpName (((MethodInfo) method).ReturnType), member_name,
 767                                         TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 768                                 return;
 769                         }
 770                         if (return_type == null) {
 771                                 Report.Error (123, loc, "A method or delegate `{0}' parameters do not match delegate `{1}' parameters",
 772                                         member_name, Delegate.FullDelegateDesc (invoke_method));
 773                                 return;
 774                         }
 775
 776                         Report.Error (407, loc, "A method or delegate `{0} {1}' return type does not match delegate `{2} {3}' return type",
 777                                 return_type.GetSignatureForError (), member_name,
 778                                 TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 779                 }
 780
 781                 public static MethodBase ImplicitStandardConversionExists (MethodGroupExpr mg, Type target_type)
 782                 {
 783                         foreach (MethodInfo mi in mg.Methods){
 784                                 MethodBase mb = Delegate.VerifyMethod (mg.DeclaringType, target_type, mg, mi, Location.Null);
 785                                 if (mb != null)
 786                                         return mb;
 787                         }
 788                         return null;
 789                 }
 790
 791                 #region IErrorHandler Members
 792
 793                 public bool NoExactMatch (EmitContext ec, MethodBase method)
 794                 {
 795                         if (TypeManager.IsGenericMethod (method))
 796                                 return false;
 797
 798                         Error_ConversionFailed (ec, method, null);
 799                         return true;
 800                 }
 801
 802                 #endregion
 803         }
 804
 805         //
 806         // Created from the conversion code
 807         //
 808         public class ImplicitDelegateCreation : DelegateCreation
 809         {
 810                 ImplicitDelegateCreation (Type t, MethodGroupExpr mg, Location l)
 811                 {
 812                         type = t;
 813                         this.method_group = mg;
 814                         loc = l;
 815                 }
 816
 817                 static public Expression Create (EmitContext ec, MethodGroupExpr mge,
 818                                                  Type target_type, Location loc)
 819                 {
 820                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, mge, loc);
 821                         return d.DoResolve (ec);
 822                 }
 823         }
 824
 825         //
 826         // A delegate-creation-expression, invoked from the `New' class
 827         //
 828         public class NewDelegate : DelegateCreation
 829         {
 830                 public ArrayList Arguments;
 831
 832                 //
 833                 // This constructor is invoked from the `New' expression
 834                 //
 835                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 836                 {
 837                         this.type = type;
 838                         this.Arguments = Arguments;
 839                         this.loc  = loc;
 840                 }
 841
 842                 public override Expression DoResolve (EmitContext ec)
 843                 {
 844                         if (Arguments == null) {
 845                                 Error_InvalidDelegateArgument ();
 846                                 return null;
 847                         }
 848
 849                         Argument a = (Argument) Arguments [0];
 850                         if (!a.ResolveMethodGroup (ec))
 851                                 return null;
 852
 853                         Expression e = a.Expr;
 854                         if (e is AnonymousMethodExpression && RootContext.Version != LanguageVersion.ISO_1) {
 855                                 e = ((AnonymousMethodExpression) e).Compatible (ec, type);
 856                                 if (e == null)
 857                                         return null;
 858                                 return e.Resolve (ec);
 859                         }
 860
 861                         method_group = e as MethodGroupExpr;
 862                         if (method_group == null) {
 863                                 if (!TypeManager.IsDelegateType (e.Type)) {
 864                                         Report.Error (149, loc, "Method name expected");
 865                                         return null;
 866                                 }
 867
 868                                 //
 869                                 // An argument is not a method but another delegate
 870                                 //
 871                                 delegate_instance_expression = e;
 872                                 method_group = new MethodGroupExpr (new MemberInfo [] {
 873                                         Delegate.GetInvokeMethod (ec.ContainerType, e.Type) }, e.Type, loc);
 874                         }
 875
 876                         if (base.DoResolve (ec) == null)
 877                                 return null;
 878
 879                         if (TypeManager.IsNullableType (method_group.DeclaringType)) {
 880                                 Report.Error (1728, loc, "Cannot use method `{0}' as delegate creation expression because it is member of Nullable type",
 881                                         TypeManager.GetFullNameSignature (delegate_method));
 882                         }
 883
 884                         if (Invocation.IsMethodExcluded (delegate_method)) {
 885                                 Report.SymbolRelatedToPreviousError (delegate_method);
 886                                 Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
 887                                         TypeManager.CSharpSignature (delegate_method));
 888                         }
 889
 890                         return this;
 891                 }
 892
 893                 void Error_InvalidDelegateArgument ()
 894                 {
 895                         Report.Error (149, loc, "Method name expected");
 896                 }
 897         }
 898
 899         public class DelegateInvocation : ExpressionStatement {
 900
 901                 readonly Expression InstanceExpr;
 902                 readonly ArrayList  Arguments;
 903
 904                 MethodBase method;
 905
 906                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 907                 {
 908                         this.InstanceExpr = instance_expr;
 909                         this.Arguments = args;
 910                         this.loc = loc;
 911                 }
 912
 913                 public override Expression DoResolve (EmitContext ec)
 914                 {
 915                         if (InstanceExpr is EventExpr) {
 916
 917                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 918
 919                                 Expression ml = MemberLookup (
 920                                         ec.ContainerType, ec.ContainerType, ei.Name,
 921                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 922
 923                                 if (ml == null) {
 924                                         //
 925                                         // If this is the case, then the Event does not belong
 926                                         // to this Type and so, according to the spec
 927                                         // cannot be accessed directly
 928                                         //
 929                                         // Note that target will not appear as an EventExpr
 930                                         // in the case it is being referenced within the same type container;
 931                                         // it will appear as a FieldExpr in that case.
 932                                         //
 933
 934                                         Assign.error70 (ei, loc);
 935                                         return null;
 936                                 }
 937                         }
 938
 939
 940                         Type del_type = InstanceExpr.Type;
 941                         if (del_type == null)
 942                                 return null;
 943
 944                         if (Arguments != null){
 945                                 foreach (Argument a in Arguments){
 946                                         if (!a.Resolve (ec, loc))
 947                                                 return null;
 948                                 }
 949                         }
 950
 951                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 952                                 return null;
 953
 954                         method = Delegate.GetInvokeMethod (ec.ContainerType, del_type);
 955                         type = ((MethodInfo) method).ReturnType;
 956                         eclass = ExprClass.Value;
 957
 958                         return this;
 959                 }
 960
 961                 public override void Emit (EmitContext ec)
 962                 {
 963                         //
 964                         // Invocation on delegates call the virtual Invoke member
 965                         // so we are always `instance' calls
 966                         //
 967                         Invocation.EmitCall (ec, false, InstanceExpr, method, Arguments, loc);
 968                 }
 969
 970                 public override void EmitStatement (EmitContext ec)
 971                 {
 972                         Emit (ec);
 973                         //
 974                         // Pop the return value if there is one
 975                         //
 976                         if (method is MethodInfo){
 977                                 Type ret = ((MethodInfo)method).ReturnType;
 978                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
 979                                         ec.ig.Emit (OpCodes.Pop);
 980                         }
 981                 }
 982
 983         }
 984 }