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 (!Parent.AsAccessible (partype, ModFlags)) {
 215                                         Report.Error (59, Location,
 216                                                       "Inconsistent accessibility: parameter type `" +
 217                                                       TypeManager.CSharpName (partype) + "' is less " +
 218                                                       "accessible than delegate `" + Name + "'");
 219                                         return false;
 220                                 }
 221                         }
 222
 223                         ReturnType = ReturnType.ResolveAsTypeTerminal (this, false);
 224                         if (ReturnType == null)
 225                                 return false;
 226
 227                         ret_type = ReturnType.Type;
 228
 229                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 230                                 Report.Error (58, Location,
 231                                               "Inconsistent accessibility: return type `" +
 232                                               TypeManager.CSharpName (ret_type) + "' is less " +
 233                                               "accessible than delegate `" + Name + "'");
 234                                 return false;
 235                         }
 236
 237                         if (RootContext.StdLib && (ret_type == TypeManager.arg_iterator_type || ret_type == TypeManager.typed_reference_type)) {
 238                                 Method.Error1599 (Location, ret_type);
 239                                 return false;
 240                         }
 241
 242                         //
 243                         // We don't have to check any others because they are all
 244                         // guaranteed to be accessible - they are standard types.
 245                         //
 246
 247                         CallingConventions cc = Parameters.CallingConvention;
 248
 249                         const MethodAttributes mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual | MethodAttributes.NewSlot;
 250
 251                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 252                                                                   mattr,
 253                                                                   cc,
 254                                                                   ret_type,
 255                                                                   Parameters.Types);
 256
 257                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 258
 259                         TypeManager.RegisterMethod (InvokeBuilder, Parameters);
 260                         member_cache.AddMember (InvokeBuilder, this);
 261
 262                         //
 263                         // BeginInvoke
 264                         //
 265
 266                         Parameters async_parameters = Parameters.MergeGenerated (Parameters,
 267                                 new Parameter (TypeManager.asynccallback_type, "callback", Parameter.Modifier.NONE, null, Location),
 268                                 new Parameter (TypeManager.object_type, "object", Parameter.Modifier.NONE, null, Location));
 269
 270                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 271                                 mattr, cc, TypeManager.iasyncresult_type, async_parameters.Types);
 272
 273                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 274                         TypeManager.RegisterMethod (BeginInvokeBuilder, async_parameters);
 275                         member_cache.AddMember (BeginInvokeBuilder, this);
 276
 277                         //
 278                         // EndInvoke is a bit more interesting, all the parameters labeled as
 279                         // out or ref have to be duplicated here.
 280                         //
 281
 282                         //
 283                         // Define parameters, and count out/ref parameters
 284                         //
 285                         Parameters end_parameters;
 286                         int out_params = 0;
 287
 288                         foreach (Parameter p in Parameters.FixedParameters) {
 289                                 if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 290                                         ++out_params;
 291                         }
 292
 293                         if (out_params > 0) {
 294                                 Type [] end_param_types = new Type [out_params];
 295                                 Parameter [] end_params = new Parameter [out_params ];
 296
 297                                 int param = 0;
 298                                 for (int i = 0; i < Parameters.FixedParameters.Length; ++i) {
 299                                         Parameter p = Parameters.FixedParameters [i];
 300                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 301                                                 continue;
 302
 303                                         end_param_types [param] = p.ExternalType();
 304                                         end_params [param] = p;
 305                                         ++param;
 306                                 }
 307                                 end_parameters = Parameters.CreateFullyResolved (end_params, end_param_types);
 308                         }
 309                         else {
 310                                 end_parameters = Parameters.EmptyReadOnlyParameters;
 311                         }
 312
 313                         end_parameters = Parameters.MergeGenerated (end_parameters,
 314                                 new Parameter (TypeManager.iasyncresult_type, "result", Parameter.Modifier.NONE, null, Location));
 315
 316                         //
 317                         // Create method, define parameters, register parameters with type system
 318                         //
 319                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_parameters.Types);
 320                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 321
 322                         end_parameters.ApplyAttributes (EndInvokeBuilder);
 323                         TypeManager.RegisterMethod (EndInvokeBuilder, end_parameters);
 324                         member_cache.AddMember (EndInvokeBuilder, this);
 325
 326                         return true;
 327                 }
 328
 329                 public override void Emit ()
 330                 {
 331                         Parameters.ApplyAttributes (InvokeBuilder);
 332
 333                         Parameters p = (Parameters)TypeManager.GetParameterData (BeginInvokeBuilder);
 334                         p.ApplyAttributes (BeginInvokeBuilder);
 335
 336                         if (OptAttributes != null) {
 337                                 OptAttributes.Emit ();
 338                         }
 339
 340                         base.Emit ();
 341                 }
 342
 343                 protected override TypeAttributes TypeAttr {
 344                         get {
 345                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 346                                         TypeAttributes.Class | TypeAttributes.Sealed |
 347                                         base.TypeAttr;
 348                         }
 349                 }
 350
 351                 public override string[] ValidAttributeTargets {
 352                         get {
 353                                 return attribute_targets;
 354                         }
 355                 }
 356
 357                 //TODO: duplicate
 358                 protected override bool VerifyClsCompliance ()
 359                 {
 360                         if (!base.VerifyClsCompliance ()) {
 361                                 return false;
 362                         }
 363
 364                         Parameters.VerifyClsCompliance ();
 365
 366                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 367                                 Report.Error (3002, Location, "Return type of `{0}' is not CLS-compliant", GetSignatureForError ());
 368                         }
 369                         return true;
 370                 }
 371
 372
 373                 public static ConstructorInfo GetConstructor (Type container_type, Type delegate_type)
 374                 {
 375                         Type dt = delegate_type;
 376 #if GMCS_SOURCE
 377                         Type[] g_args = null;
 378                         if (delegate_type.IsGenericType) {
 379                                 g_args = delegate_type.GetGenericArguments ();
 380                                 delegate_type = delegate_type.GetGenericTypeDefinition ();
 381                         }
 382 #endif
 383
 384                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 385                         if (d != null) {
 386 #if GMCS_SOURCE
 387                                 if (g_args != null)
 388                                         return TypeBuilder.GetConstructor (dt, d.ConstructorBuilder);
 389 #endif
 390                                 return d.ConstructorBuilder;
 391                         }
 392
 393                         Expression ml = Expression.MemberLookup (container_type,
 394                                 null, dt, ConstructorInfo.ConstructorName, MemberTypes.Constructor,
 395                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly, Location.Null);
 396
 397                         MethodGroupExpr mg = ml as MethodGroupExpr;
 398                         if (mg == null) {
 399                                 Report.Error (-100, Location.Null, "Internal error: could not find delegate constructor!");
 400                                 // FIXME: null will cause a crash later
 401                                 return null;
 402                         }
 403
 404                         return (ConstructorInfo) mg.Methods[0];
 405                 }
 406
 407                 //
 408                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 409                 // to extract the signature of a delegate.
 410                 //
 411                 public static MethodInfo GetInvokeMethod (Type container_type, Type delegate_type)
 412                 {
 413                         Type dt = delegate_type;
 414 #if GMCS_SOURCE
 415                         Type[] g_args = null;
 416                         if (delegate_type.IsGenericType) {
 417                                 g_args = delegate_type.GetGenericArguments ();
 418                                 delegate_type = delegate_type.GetGenericTypeDefinition ();
 419                         }
 420 #endif
 421                         Delegate d = TypeManager.LookupDelegate (delegate_type);
 422                         if (d != null) {
 423 #if GMCS_SOURCE
 424                                 if (g_args != null) {
 425                                         MethodInfo invoke = TypeBuilder.GetMethod (dt, d.InvokeBuilder);
 426 #if MS_COMPATIBLE
 427                                         Parameters p = (Parameters) d.Parameters.InflateTypes (g_args, g_args);
 428                                         TypeManager.RegisterMethod (invoke, p);
 429 #endif
 430                                         return invoke;
 431                                 }
 432 #endif
 433                                 return d.InvokeBuilder;
 434                         }
 435
 436                         Expression ml = Expression.MemberLookup (container_type, null, dt,
 437                                 "Invoke", Location.Null);
 438
 439                         MethodGroupExpr mg = ml as MethodGroupExpr;
 440                         if (mg == null) {
 441                                 Report.Error (-100, Location.Null, "Internal error: could not find Invoke method!");
 442                                 // FIXME: null will cause a crash later
 443                                 return null;
 444                         }
 445
 446                         return (MethodInfo) mg.Methods[0];
 447                 }
 448
 449                 public static bool IsTypeCovariant (Expression a, Type b)
 450                 {
 451                         Type a_type = a.Type;
 452                         if (a_type == b)
 453                                 return true;
 454
 455                         if (RootContext.Version == LanguageVersion.ISO_1)
 456                                 return false;
 457
 458                         if (a.Type.IsValueType)
 459                                 return false;
 460
 461                         return Convert.ImplicitReferenceConversionCore (
 462                                 a, b);
 463                 }
 464
 465                 /// <summary>
 466                 ///  Verifies whether the method in question is compatible with the delegate
 467                 ///  Returns the method itself if okay and null if not.
 468                 /// </summary>
 469                 public static MethodBase VerifyMethod (Type container_type, Type delegate_type,
 470                                                        MethodGroupExpr old_mg, MethodBase mb,
 471                                                        Location loc)
 472                 {
 473                         MethodInfo invoke_mb = GetInvokeMethod (container_type, delegate_type);
 474                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 475
 476 #if GMCS_SOURCE
 477                         if (!old_mg.HasTypeArguments &&
 478                             !TypeManager.InferTypeArguments (invoke_pd, ref mb))
 479                                 return null;
 480 #endif
 481
 482                         ParameterData pd = TypeManager.GetParameterData (mb);
 483
 484                         if (invoke_pd.Count != pd.Count)
 485                                 return null;
 486
 487                         for (int i = pd.Count; i > 0; ) {
 488                                 i--;
 489
 490                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 491                                 Type pd_type = pd.ParameterType (i);
 492                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 493                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 494
 495                                 invoke_pd_type_mod &= ~Parameter.Modifier.PARAMS;
 496                                 pd_type_mod &= ~Parameter.Modifier.PARAMS;
 497
 498                                 if (invoke_pd_type_mod != pd_type_mod)
 499                                         return null;
 500
 501                                 if (invoke_pd_type == pd_type)
 502                                         continue;
 503
 504                                 //if (!IsTypeCovariant (invoke_pd_type, pd_type))
 505                                 //      return null;
 506
 507                                 if (RootContext.Version == LanguageVersion.ISO_1)
 508                                         return null;
 509                         }
 510
 511                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 512                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 513                         if (invoke_mb_retval == mb_retval)
 514                                 return mb;
 515
 516                         //if (!IsTypeCovariant (mb_retval, invoke_mb_retval))
 517                         //      return null;
 518
 519                         if (RootContext.Version == LanguageVersion.ISO_1)
 520                                 return null;
 521
 522                         return mb;
 523                 }
 524
 525                 // <summary>
 526                 //  Verifies whether the invocation arguments are compatible with the
 527                 //  delegate's target method
 528                 // </summary>
 529                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 530                                                         ArrayList args, Location loc)
 531                 {
 532                         int arg_count;
 533
 534                         if (args == null)
 535                                 arg_count = 0;
 536                         else
 537                                 arg_count = args.Count;
 538
 539                         Expression ml = Expression.MemberLookup (
 540                                 ec.ContainerType, delegate_type, "Invoke", loc);
 541
 542                         MethodGroupExpr me = ml as MethodGroupExpr;
 543                         if (me == null) {
 544                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 545                                 return false;
 546                         }
 547
 548                         MethodBase mb = GetInvokeMethod (ec.ContainerType, delegate_type);
 549                         ParameterData pd = TypeManager.GetParameterData (mb);
 550
 551                         int pd_count = pd.Count;
 552
 553                         bool params_method = pd.HasParams;
 554                         bool is_params_applicable = false;
 555                         me.DelegateType = delegate_type;
 556                         bool is_applicable = me.IsApplicable (ec, args, arg_count, ref mb) == 0;
 557
 558                         if (!is_applicable && params_method &&
 559                             me.IsParamsMethodApplicable (ec, args, arg_count, ref mb))
 560                                 is_applicable = is_params_applicable = true;
 561
 562                         if (!is_applicable && !params_method && arg_count != pd_count) {
 563                                 Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 564                                         TypeManager.CSharpName (delegate_type), arg_count.ToString ());
 565                                 return false;
 566                         }
 567
 568                         return me.VerifyArgumentsCompat (
 569                                         ec, args, arg_count, mb,
 570                                         is_params_applicable || (!is_applicable && params_method),
 571                                         false, loc);
 572                 }
 573
 574                 public static string FullDelegateDesc (MethodBase invoke_method)
 575                 {
 576                         return TypeManager.GetFullNameSignature (invoke_method).Replace (".Invoke", "");
 577                 }
 578
 579                 public override MemberCache MemberCache {
 580                         get {
 581                                 return member_cache;
 582                         }
 583                 }
 584
 585                 public Expression InstanceExpression {
 586                         get {
 587                                 return instance_expr;
 588                         }
 589                         set {
 590                                 instance_expr = value;
 591                         }
 592                 }
 593
 594                 public MethodBase TargetMethod {
 595                         get {
 596                                 return delegate_method;
 597                         }
 598                         set {
 599                                 delegate_method = value;
 600                         }
 601                 }
 602
 603                 public Type TargetReturnType {
 604                         get {
 605                                 return ret_type;
 606                         }
 607                 }
 608
 609                 public override AttributeTargets AttributeTargets {
 610                         get {
 611                                 return AttributeTargets.Delegate;
 612                         }
 613                 }
 614
 615                 //
 616                 //   Represents header string for documentation comment.
 617                 //
 618                 public override string DocCommentHeader {
 619                         get { return "T:"; }
 620                 }
 621
 622                 #region IMemberContainer Members
 623
 624                 string IMemberContainer.Name
 625                 {
 626                         get { throw new NotImplementedException (); }
 627                 }
 628
 629                 Type IMemberContainer.Type
 630                 {
 631                         get { throw new NotImplementedException (); }
 632                 }
 633
 634                 MemberCache IMemberContainer.BaseCache
 635                 {
 636                         get { throw new NotImplementedException (); }
 637                 }
 638
 639                 bool IMemberContainer.IsInterface {
 640                         get {
 641                                 return false;
 642                         }
 643                 }
 644
 645                 MemberList IMemberContainer.GetMembers (MemberTypes mt, BindingFlags bf)
 646                 {
 647                         throw new NotImplementedException ();
 648                 }
 649
 650                 #endregion
 651         }
 652
 653         //
 654         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 655         //
 656         public abstract class DelegateCreation : Expression, MethodGroupExpr.IErrorHandler
 657         {
 658                 protected ConstructorInfo constructor_method;
 659                 protected MethodBase delegate_method;
 660                 // We keep this to handle IsBase only
 661                 protected MethodGroupExpr method_group;
 662                 protected Expression delegate_instance_expression;
 663
 664                 ArrayList CreateDelegateMethodArguments (MethodInfo invoke_method)
 665                 {
 666                         ParameterData pd = TypeManager.GetParameterData (invoke_method);
 667                         ArrayList delegate_arguments = new ArrayList (pd.Count);
 668                         for (int i = 0; i < pd.Count; ++i) {
 669                                 Argument.AType atype_modifier;
 670                                 Type atype = pd.Types [i];
 671                                 switch (pd.ParameterModifier (i)) {
 672                                         case Parameter.Modifier.REF:
 673                                                 atype_modifier = Argument.AType.Ref;
 674                                                 atype = atype.GetElementType ();
 675                                                 break;
 676                                         case Parameter.Modifier.OUT:
 677                                                 atype_modifier = Argument.AType.Out;
 678                                                 atype = atype.GetElementType ();
 679                                                 break;
 680                                         case Parameter.Modifier.ARGLIST:
 681                                                 // TODO: investigate and test
 682                                                 throw new NotImplementedException ();
 683                                         default:
 684                                                 atype_modifier = Argument.AType.Expression;
 685                                                 break;
 686                                 }
 687                                 delegate_arguments.Add (new Argument (new TypeExpression (atype, loc), atype_modifier));
 688                         }
 689                         return delegate_arguments;
 690                 }
 691
 692                 public override Expression DoResolve (EmitContext ec)
 693                 {
 694                         constructor_method = Delegate.GetConstructor (ec.ContainerType, type);
 695
 696                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.ContainerType, type);
 697                         method_group.DelegateType = type;
 698                         method_group.CustomErrorHandler = this;
 699                         method_group = method_group.OverloadResolve (ec, CreateDelegateMethodArguments (invoke_method), 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                         if (method_group.InstanceExpression != null)
 718                                 delegate_instance_expression = method_group.InstanceExpression;
 719                         else if (!ec.IsStatic)
 720                                 delegate_instance_expression = ec.GetThis (loc);
 721
 722                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 723                                 delegate_instance_expression = new BoxedCast (
 724                                         delegate_instance_expression, TypeManager.object_type);
 725
 726                         eclass = ExprClass.Value;
 727                         return this;
 728                 }
 729
 730                 public override void Emit (EmitContext ec)
 731                 {
 732                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 733                                 ec.ig.Emit (OpCodes.Ldnull);
 734                         else
 735                                 delegate_instance_expression.Emit (ec);
 736
 737                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 738                                 ec.ig.Emit (OpCodes.Dup);
 739                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 740                         } else
 741                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 742                         ec.ig.Emit (OpCodes.Newobj, constructor_method);
 743                 }
 744
 745                 void Error_ConversionFailed (EmitContext ec, MethodBase method, Expression return_type)
 746                 {
 747                         MethodInfo invoke_method = Delegate.GetInvokeMethod (ec.ContainerType, type);
 748                         string member_name = delegate_instance_expression != null ?
 749                                 Delegate.FullDelegateDesc (method) :
 750                                 TypeManager.GetFullNameSignature (method);
 751
 752                         Report.SymbolRelatedToPreviousError (type);
 753                         Report.SymbolRelatedToPreviousError (method);
 754                         if (RootContext.Version == LanguageVersion.ISO_1) {
 755                                 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",
 756                                         TypeManager.CSharpName (((MethodInfo) method).ReturnType), member_name,
 757                                         TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 758                                 return;
 759                         }
 760                         if (return_type == null) {
 761                                 Report.Error (123, loc, "A method or delegate `{0}' parameters do not match delegate `{1}' parameters",
 762                                         member_name, Delegate.FullDelegateDesc (invoke_method));
 763                                 return;
 764                         }
 765
 766                         Report.Error (407, loc, "A method or delegate `{0} {1}' return type does not match delegate `{2} {3}' return type",
 767                                 return_type.GetSignatureForError (), member_name,
 768                                 TypeManager.CSharpName (invoke_method.ReturnType), Delegate.FullDelegateDesc (invoke_method));
 769                 }
 770
 771                 public static MethodBase ImplicitStandardConversionExists (MethodGroupExpr mg, Type target_type)
 772                 {
 773                         foreach (MethodInfo mi in mg.Methods){
 774                                 MethodBase mb = Delegate.VerifyMethod (mg.DeclaringType, target_type, mg, mi, Location.Null);
 775                                 if (mb != null)
 776                                         return mb;
 777                         }
 778                         return null;
 779                 }
 780
 781                 #region IErrorHandler Members
 782
 783                 public bool NoExactMatch (EmitContext ec, MethodBase method)
 784                 {
 785                         if (TypeManager.IsGenericMethod (method))
 786                                 return false;
 787
 788                         Error_ConversionFailed (ec, method, null);
 789                         return true;
 790                 }
 791
 792                 #endregion
 793         }
 794
 795         //
 796         // Created from the conversion code
 797         //
 798         public class ImplicitDelegateCreation : DelegateCreation
 799         {
 800                 ImplicitDelegateCreation (Type t, MethodGroupExpr mg, Location l)
 801                 {
 802                         type = t;
 803                         this.method_group = mg;
 804                         loc = l;
 805                 }
 806
 807                 static public Expression Create (EmitContext ec, MethodGroupExpr mge,
 808                                                  Type target_type, Location loc)
 809                 {
 810                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, mge, loc);
 811                         return d.DoResolve (ec);
 812                 }
 813         }
 814
 815         //
 816         // A delegate-creation-expression, invoked from the `New' class
 817         //
 818         public class NewDelegate : DelegateCreation
 819         {
 820                 public ArrayList Arguments;
 821
 822                 //
 823                 // This constructor is invoked from the `New' expression
 824                 //
 825                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 826                 {
 827                         this.type = type;
 828                         this.Arguments = Arguments;
 829                         this.loc  = loc;
 830                 }
 831
 832                 public override Expression DoResolve (EmitContext ec)
 833                 {
 834                         if (Arguments == null) {
 835                                 Error_InvalidDelegateArgument ();
 836                                 return null;
 837                         }
 838
 839                         Argument a = (Argument) Arguments [0];
 840                         if (!a.ResolveMethodGroup (ec))
 841                                 return null;
 842
 843                         Expression e = a.Expr;
 844                         if (e is AnonymousMethodExpression && RootContext.Version != LanguageVersion.ISO_1) {
 845                                 AnonymousMethod am = ((AnonymousMethodExpression) e).Compatible (ec, type);
 846                                 if (am == null)
 847                                         return null;
 848                                 return am.Resolve (ec);
 849                         }
 850
 851                         method_group = e as MethodGroupExpr;
 852                         if (method_group == null) {
 853                                 if (!TypeManager.IsDelegateType (e.Type)) {
 854                                         Report.Error (149, loc, "Method name expected");
 855                                         return null;
 856                                 }
 857
 858                                 //
 859                                 // An argument is not a method but another delegate
 860                                 //
 861                                 delegate_instance_expression = e;
 862                                 method_group = new MethodGroupExpr (new MemberInfo [] {
 863                                         Delegate.GetInvokeMethod (ec.ContainerType, e.Type) }, e.Type, loc);
 864                         }
 865
 866                         if (base.DoResolve (ec) == null)
 867                                 return null;
 868
 869                         if (TypeManager.IsNullableType (method_group.DeclaringType)) {
 870                                 Report.Error (1728, loc, "Cannot use method `{0}' as delegate creation expression because it is member of Nullable type",
 871                                         TypeManager.GetFullNameSignature (delegate_method));
 872                         }
 873
 874                         if (Invocation.IsMethodExcluded (delegate_method)) {
 875                                 Report.SymbolRelatedToPreviousError (delegate_method);
 876                                 Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
 877                                         TypeManager.CSharpSignature (delegate_method));
 878                         }
 879
 880                         return this;
 881                 }
 882
 883                 void Error_InvalidDelegateArgument ()
 884                 {
 885                         Report.Error (149, loc, "Method name expected");
 886                 }
 887         }
 888
 889         public class DelegateInvocation : ExpressionStatement {
 890
 891                 readonly Expression InstanceExpr;
 892                 readonly ArrayList  Arguments;
 893
 894                 MethodBase method;
 895
 896                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 897                 {
 898                         this.InstanceExpr = instance_expr;
 899                         this.Arguments = args;
 900                         this.loc = loc;
 901                 }
 902
 903                 public override Expression DoResolve (EmitContext ec)
 904                 {
 905                         if (InstanceExpr is EventExpr) {
 906
 907                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 908
 909                                 Expression ml = MemberLookup (
 910                                         ec.ContainerType, ec.ContainerType, ei.Name,
 911                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 912
 913                                 if (ml == null) {
 914                                         //
 915                                         // If this is the case, then the Event does not belong
 916                                         // to this Type and so, according to the spec
 917                                         // cannot be accessed directly
 918                                         //
 919                                         // Note that target will not appear as an EventExpr
 920                                         // in the case it is being referenced within the same type container;
 921                                         // it will appear as a FieldExpr in that case.
 922                                         //
 923
 924                                         Assign.error70 (ei, loc);
 925                                         return null;
 926                                 }
 927                         }
 928
 929
 930                         Type del_type = InstanceExpr.Type;
 931                         if (del_type == null)
 932                                 return null;
 933
 934                         if (Arguments != null){
 935                                 foreach (Argument a in Arguments){
 936                                         if (!a.Resolve (ec, loc))
 937                                                 return null;
 938                                 }
 939                         }
 940
 941                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 942                                 return null;
 943
 944                         method = Delegate.GetInvokeMethod (ec.ContainerType, del_type);
 945                         type = ((MethodInfo) method).ReturnType;
 946                         eclass = ExprClass.Value;
 947
 948                         return this;
 949                 }
 950
 951                 public override void Emit (EmitContext ec)
 952                 {
 953                         //
 954                         // Invocation on delegates call the virtual Invoke member
 955                         // so we are always `instance' calls
 956                         //
 957                         Invocation.EmitCall (ec, false, InstanceExpr, method, Arguments, loc);
 958                 }
 959
 960                 public override void EmitStatement (EmitContext ec)
 961                 {
 962                         Emit (ec);
 963                         //
 964                         // Pop the return value if there is one
 965                         //
 966                         if (method is MethodInfo){
 967                                 Type ret = ((MethodInfo)method).ReturnType;
 968                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
 969                                         ec.ig.Emit (OpCodes.Pop);
 970                         }
 971                 }
 972
 973         }
 974 }